Faceted totally internally reflecting lens with individually curved faces on facets

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FACETED TOTALLY INTERNALLY REFLECTING

the Sensitivity to manufacturing error over that of the

LENS WITH INDIVIDUALLY CURVED FACES ON present invention, which redirects radiant energy

FACETS

through itself with only a single reflection.

SUMMARY OF THE INVENTION

BACKGROUND OF THE INVENTION It is a major object of the TIR lens to overcome the This invention relates generally to radiant, particu above-described problems of, and difficulties with, the larly electromagnetic, energy concentration, redirec prior art, and to provide a means to collect and employ tion, and manipulation, and improves over the subject radiant energy in a very cost-effective and efficient matter of U.S. Pat. No. 4,337,759. It more particularly 10 manner, using a new basic tool with applications that concerns apparatus and method for employing a trans include the collection, concentration, redirection, and parent means with elements thereof using Total Internal wavelength separation of radiant energy. Reflection (TIR), alone or in conjunction with refrac The present invention, which improves over the sub tion; such elements acting in concert with purely refrac 15 ject matter of U.S. Pat. No. 4,337,759, is basically char tive elements (as those in a Fresnel lens) and/or metal acterized by the use of a transparent means employing mirrors to redirect radiant energy to or from a predeter elements to redirect radiant energy by means of TIR mined Zone or zones; such redirection having a prede alone, or in conjunction with refraction, such means termined degree of concentration and/or chromatic positioned between the radiant energy source and a dispersion. The zones have sources of light, as in pho toillumination, or radiant energy receiving means for 20 receiver.

common

Each element redirects radiant energy upon a target Zone or zones, during the energy's inter conversion of the redirected energy to thermal, electric, nal passage through chemical, or mechanical forms. Alternatively, a further ray enters through thetheentry element. A properly oriented transparent means is employed, with elements thereof tive face, which redirects it face and strikes the reflec toward the exit face, the having the same design principle (TIR) as above; said three faces comprising the active faces for that ray. In further transparent means acting as a secondary radia 25 addition, the lens means is associated with at least one of tion redirector for the purpose of magnifying the degree the faces for redirecting radiant energy passing between of concentration and/or chromatic dispersion of the the entry and exit faces via the TIR face. radiant energy redirected by the primary transparent Accordingly, the present invention is characterized can S.

The prior art of radiant energy concentration and 30 by the passage of redirected radiant energy entirely through the transmitting body means and out the oppo illumination in general consists of two major types, as exemplified by refractive and reflective astronomical site side from which it entered after transmission via telescopes: a refractive lens positioned in front of a associated lens means. This invention constitutes a third receiver or light source, or a retro-reflective mirror class of radiant energy concentrators that also has appli positioned behind a receiver or light source. The corre 35 cations to other forms of radiant energy redirection sponding devices in the prior art of solar energy con than concentration, such as wavelength separation or centration are the Fresnel lens and the parabolic reflec collimation. Other surfaces of the element may be inac tor, which focus solar energy on a target. Furthermore, tive for the ray of interest (e.g., as in solar energy con there are non-imaging, reflecting concentrators that centration of relatively parallel rays) but may impinge have the advantage of fixed daily (non-tracking) posi upon improperly oriented rays (e.g., diffuse skylight of tion with only seasonal adjustments, but the disadvan off-angle sunlight).

tage of requiring relatively large reflector areas and The TIR elements may be contiguous, forming a delivering only relatively low energy concentrations. transparent cover means, or separated to allow unde Fresnel lenses are devices comprising purely refrac flected light to pass between them, for example to be tive elements, but they have physically inherent limita 45 focused by a mirror upon the back of the target, which tions of redirecting radiant energy that give high is thereby illuminated from all directions. f/ratios and bulky concentrator structure. Moreover, Each element may redirect all of the parallel rays linear Fresnel lenses have, for off-angles in the direction entering it into a single new direction, or split them into of the grooves, focusing errors, that are also inherent in several directions, with or without wavelength separa the laws of refraction, and that limit one-axis tracking 50 tion, which can be controllably achieved by the inde configurations to relatively low concentration. pendent, non-normal angling of the entry face and/or Parabolic reflector concentrators have seen wide the exit face to the parallel rays being redirected, or spread use, but are subject to losses of received radiant achieved by diffraction gratings upon the exit face, energy because the receiver is situated between the which can be implemented by the replicative techniques source and the reflector, which is thereby shaded, pre 55 of binary optics. While TIR alone is limited to incident venting in particular the utilization of large heat engines angles greater than the critical angle and therefore to at the focus. Furthermore, the receiver is exposed to any redirective bend angles less than 180°-2 critical environmental degradation and thermal losses, and the angle (about 96 for acrylic), additional redirection is inclusion of a protective transparent cover means about possible with or without wavelength separation by the the receiver will merely reduce the system's optical 60 above-mentioned, non-normal angling of the entry and efficiency. exit faces. Such large bend angles enable a given diame Another reflecting system has appeared in the litera ter transparent means to be much closer to the target ture, as reported by Rabl in Solar Energy, Vol. 19, No. than a means limited to refraction alone, thereby greatly 5. It employs a retro-reflecting means with elements reducing the necessary support structure. Furthermore, that have two TIR faces to redirect radiant energy out 65 a transparent means employing up to 90° bend angles the same side as it came in. Its only improvement over can utilize a flat mirror extending from the target to the a metal mirror of the same shape is a potentially higher rim of the means, thereby doubling solar concentration reflectivity; but the double internal reflection doubles or doubling intercept efficiency for a light source.

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Since a given acceptance angle (of deviation from a matrix inversion method that assumes quasi-linearity parallelism) produces a proportional requirement for in the neighborhood of the solution hyperspace. This target size, the target can be bisected by the plane of the requires some prior knowledge of this hyperspace so mirror, and result in an actual target of half the original that a starting point for the solution search is within the size, with no decrease in acceptance angle, by insulating quasi-linear regime. This prior knowledge depends the half of the target facing away from the redirected upon whether the facet is triangular or quadrilateral. body means. Conversely, the target can be doubled in The former give wider interfacet slot angles and thus size to give a doubled acceptance angle, and then are easier to make; but the latter add another degree of halved by the mirror back to its original area. This surprising potential for halving thermal losses is unique 10 freedom, enabling a wider choice of overall lens shapes. The angle of this fourth, optically inactive, side of the to the present invention, being unavailable for the para facet would typically be set at the minimum draft angle bolic reflector of 90 rim angle because the plane mirror for pulling the lens from a mold (about 2). In the case would shade the aperture, and also unavailable for the of small lenses with only a few facets, there is also the Fresnel lens because of its far lower rim angle. Unlike possibility of an adjacent facet being larger or smaller the Fresnel lens, chromatic aberration is completely 15 than its neighbors, in order to raise the lens height and independent of bend angle and can have any positive, improve collimation.

zero, or negative values desired for such wavelength The relative facet positions, as determined by the separation applications as solar illumination or bandgap non-interference criterion, determine the overall lens tailored photovoltaic cells. Unlike the parabolic reflec tor, the redirective bend angle of an element is indepen 20 profile, which should be low or high depending upon the application. In a solar concentrator, the lens height dent of its location, greatly adding to design flexibility. should

(Since the parabolic reflector is a smooth continuum, image. Inbeaminimized converging to reduce spot size of the solar or collimating TIR illumination there can be no arbitrary variations in redirective bend system, it is advantageous to have somewhat more lens angle from one spot to a neighboring one.) height, so that the apparent size of the source is reduced The first of the present invention's improvements 25 over the subject matter of U.S. Pat. No. 4,337,759 is the at the central facets, and the output beam is thereby tightened. This consideration does not hold for diverg curvature of the faces of the individual lens elements.

This curvature may be provided at one, two or all three ing TIR lenses, because only efficiency, and not beam tightness, is required.

of the faces (entry, exit and TIR) and, for example, may constitute a concave entry face, a convex exit face, 30 An important use of facet curvature is in a small TIR and/or a convex TIR face. Radiant energy handling is lens with only a few facets, such as a collimator for a thus improved over a flat-faceted face system, as for light-emitting diode. Molding very small facets may be example in redirection of rays from a line or point undesirable because of difficulties in making the mold. source, within constraints of interior shadowing and Curved facet faces enable relatively large facets to per TIR face slope, to produce either parallel or converging 35 form as accurately as small ones. Lenses for light-emit output beams in a system using multiple faces. Also, ting diodes are of interest for red lamps at the rear of improvements in ray collimation and focusing are real automobiles. In fact, the TIR lens can be incorporated ized; and design freedom is enhanced, since each face into the conventional transparent cover of an LED, can be individually curved or various combination of greatly improving its luminous efficiency. face curvatures can be employed to minimize aberra 40 Further improvements over the subject matter of tions, due to the finite size of the facets. For ease of U.S. Pat. No. 4,337,759 are:

quality control of manufacturing, the curved facet faces A lens that redirects light from a source in order to can form spheres with centers on the axis of rotational focus it on a spot in front of the lens. symmetry of the lens. When an axially symmetric lens is There are two reasons that the TIR lens is superior to made by molding a rigid material, undercut interior 45 conventional ellipsoidal reflectors for this application. faces are precluded, which limits the curvature of those First, the lens and its associated planar back mirror faces. This constraint is not applicable to elastomeric collect all of the output of a light source and focus it. lens materials. The ellipsoidal reflector typically collects only a fourth The facet design of the TIR lens has four degrees of of a source's output.

freedom: the angle of the entry face, the angle of the 50 Second, facet configurations are possible with effi TIR face, the angle of the exit face, and the position of cient focusing power; that is, at the center of the focal the inwardly adjacent facet. A full design solution re spot, the entire lens would appear to be as bright as the quires that four requirements be used to derive these light source itself, a condition known as “full flashing four angles. In many of the designs illustrated below, important for the proper functioning of microfiche and prearranged choices restricted the degrees of freedom. 55 slide projectors. Because of astigmatic aberrations in In general, however, the requirements are: herent in the ellipsoidal reflector, it is never fully a) the redirection of light from source to target; flashed, producing instead a much broader focal spot. b) the full interception of light by the TIR face; Full flashing by the TIR lens is made possible by facet c) the full illumination of the exit face, for maximum ing of the exit so that stairsteps have their “risers' paral thermodynamic efficiency; and lel to inner rays then emerging from the exit face. Then, d) the non-interference of a facet's input and output the full exit face of the facet must be illuminated by light rays by the next facet inwards. from the TIR face, a condition that can be fulfilled by Typically, a TIR lens is generated from the outer curvature of the TIR face.

most, or rim, facet inwards in a facet-by-facet, numeri Furthermore, the exit face can have about the same cally controlled iteration. The four requirements form a 65 refractive bending as the entry face, preventing un set of nonlinear equations in four unknowns to be solved wanted image magnification that broadens the focal for their roots. Because there is no general method of spot. The individual convex curvature on each of the solving such equations, typical computer routines apply facet faces is vital to the success of this design:

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entry-face curvature enables the entire TIR facet to total incident angle that exceeds the critical angle for be utilized, through a slight convergence that pre total internal reflection. Most of the facet designs used vents any light from missing the TIR face; in radially symmetric lenses will, when put into linear TIR-face curvature enables the entire exit face to be lenses, be subject to this whenever the out-of-place illuminated, by preventing any light from striking angle exceeds 40', which encompasses half of all rays the stairstep risers or the adjacent TIR face; and emitted from a Lambertian, or uniformly emitting, exit-face curvature focuses light onto the target, elim Source. This trapping of light within the lens can be inating the effects of finite facet size. remedied by corrugation along the outer face of the This focusing configuration would have two promi lens, which unfortunately nent applications that considerably improve the light 10 extrusion because the crossprecludes section manufacturing by is no longer con utilization efficiency of the prior art: stant. Another method is binary optics outcoupling Imaging projectors for slides, motion pictures, or through microfiche. Current designs use ellipsoidal reflectors lens. miniature stepped patterns on the outside of the that have inherently low intercept efficiency (i.e., the fraction of the source output that actually ends up in the 5 dalAfluorescent more useful lens design would be applied to a toroi lamp. The TIR lens profile would have output image of the device).

The TIR lens of the present invention can be used in the toroidal lamp. Theover its axis of symmetry the circular cross-section of complete lens would be a figure conjunction with an aspheric lens in order to remove of the cosine-4th illumination non-uniformity typical of thanrevolution with its axis being that of the toroid rather the center of the lens profile. The more slender the the prior art. This version of the TIR lens typically has 20 toroidal lamp, the better could its light be controlled by stepped exit faces, with the risers angled parallel to the the converging rays, to ensure spatial continuity of the lens. Presently, there are no reflectors that can col focal cone. The faces of the facets can be curved so as lect the light of such a lamp and put most of it into a to augment the action of the auxiliary lens. forward-going beam. This toroidal TIR lens would be Another advantage of the TIR lens for this applica 25 very useful for battery-powered fluorescent lanterns, tion is that it azimuthally smears out any structure in the which ever, currently cannot provide any focusing whatso source, removing a source of pattern noise that is inher ent in the imaging action of an ellipsoidal reflector. A collimating TIR lens made of silicon. Because of Illumination injector for optical fiber bundles and the high refractive index of this material, the re light pipes. Prior arthere also uses ellipsoidal reflectors. 30 fractive faces of its facets would be somewhat dif The TIR lens would have a focal cone half angle ferently angled than those of a glass lens. The appli matched to the acceptance angle of the target. cation for a silicon lens is for the collimation of Light-gathering means for spectrometers that analyze infrared light and the exclusion of visible light the diffusely emitted light of samples that have been (because silicon absorbs all wavelengths shorter stimulated to produce Raman or fluorescent light. Con 35 than 1.1 micrometers). The purpose of this applica ventional spectrometers typically collect this light with tion is the jamming of the guidance sensors of heat microscope objectives, which also deliver tightly fo seeking, anti-aircraft rockets by focused beams of cused (50 micrometers) laser light to the sample. These pulsating infrared light. The prior art uses much objectives typically have a focal length equal to their less efficient parabolic reflectors in conjunction diameter, so that they subtend about 50 and collect 5% with a silicon window. The silicon TIR lens would of the diffusely emitted output. The converging TIR be an important new kind of infrared luminator, as lens can collect over half of this emission, a factor often found in many night-vision systems. improvement, greatly aiding spectral analysis because The superiority of the present invention can be seen of the greater signal to noise ratio. in its application to prisms with curved cross sections, A TIR lens that redirects light from a source in order 45 arrays of connected linear or toroidal prisms acting in to form a diverging cone of light, as in floodlight concert, redirection of rays from a line or point source, ing applications. For cone angles of 45 or less, this concentration of spherical or plane waves, better colli lens is more efficient than a conventional congru mation than parabolic mirrors, and 0 more efficient ent reflector and much more compact. This diver focusing than ellipsoidal mirrors.

gence can either be for uniform illumination, or it 50 These and other objects and advantages of the inven can take the appearance of effectively coming from tion, as well as the details of an illustrative embodiment, a virtual source located behind the lens, with ap will be more fully understood from the following speci propriate facet-face curvatures compensating for fication and drawings, in which:

the different distances of the facets from the source.

Two types of linearly symmetric TIR lenses for cy 55 DRAWING DESCRIPTION lindrical sources (such as fluorescent tubes): FIG. 1 is a vertical section in elevation showing one One that confines its output to a relatively narrow form of apparatus embodying the invention; off-axis angle. With the prior art, this is possible FIG. 2 is a vertical section in elevation showing an only with quite deep and bulky reflectors. other form of apparatus embodying the invention; One that reduces its on-axis output and enhances FIG.3 is an enlarged section onlines 3-3 of FIG. 2; the lateral output, in order to produce uniform FIGS. 4a-4e are enlarged sections through elements illuminance on a nearby surface that is being of various configurations;

used for indirect lighting. Such a shape appears FIG. 5 is a view like FIG. 1 showing a portion of a very different from other TIR lenses. solar optical concentrator of somewhat different and Linear TIR lenses have somewhat of a handicap from 65 employed configuration;

sagittal ray internal reflection, whereby rays emitted FIG. 6 is a schematic showing two devices, operating from the linear source at a large out-of-plane angle with in conjunction, one of which is like that of FIG. 1 or 5, the lens cross section will encounter the exit face at a and the other being a collimator;

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FIG. 7 is an enlarged section through a collimator as faces 24 and 14 of the projecting portions of the facets. used in FIG. 6; Faces 24 are inactive surfaces, i.e., do not pass the radia FIGS. 8, 9, 10a, 10b, 11, 13, 14 and 15 are schematics tion. See for example representative rays 25 and 26 in showing different applications of the radiant energy FIG. 1. Ray 25 is redirected by its associated facet al concentrating means; and FIG.11a is an enlargement of 5 most 90 toward the target, near the outer edge 27 of the a portion of FIG. 11 designated at 11a–11a; TIR lens 10. Study of FIGS. 1 and 4 will show that FIGS. 12a and 12b are fragmentary sections showing angle a (the bend angle of the ray) increases for facets modified concentrators; increasing in distance from axis or plane 18; and that FIGS. 16-18 show various curved lens surface ar angle g (the angularity of face 14 relative to a line or rangements; 10 plane parallel to line or plane 18) increases for facets FIGS. 19a–19c. are sections producing light rays of increasing in distance from 18. Also, the entry faces 12 varying angularity, as shown; form stairstep patterns.

FIG.20 is a section of a facet with three curved faces, FIG. 1 further shows a Fresnel lens 29 associated illustrating the general principles of facet design; with TIR lens or body 10, and located at a mid-portion FIG. 21 is a section showing a further modified radi 15 of the latter; thus Fresnel lens 29, which refracts inci ant energy concentrating means for use with a light dent radiant energy toward target 15, is located in the emitting diode; path of rays 30 which are redirected the least, i.e., at the FIG. 22 is a section showing yet another modified smallest angles, toward the target. Lens 29 may be inte radiant energy concentrating means made of silicon to gral with lens 10, for example.

pass infrared (IR) rays; 20 Further, a reflector or mirror surface is shown at 30 FIG. 23 is a section showing a radiant energy trans spaced from and facing the facets at the target side mitting body means, as in FIG. 21a, directing converg thereof. Surface 30 is arranged to reflect stray or diver ing light toward a light pipe; gent radiation from the extreme outward facets toward FIG. 24 is a section showing a radiant energy trans the target. See ray 31 in this regard, and reflection point mitting means, directing diverging light as in a flood 25 31a. This allows target 15 to halve the area exposed to light; heat loss that it would have without surface 30, since FIG. 25 is a section showing a radiant energy trans the bottom non-illuminated half could be well insulated. mitting means, directing light from a layer-stimulated Also shown in FIG. 1 is one form of means to con sample to converge into a spectroscopic analyzer; and trollably tilt the assembly of lenses 10 and 29 and reflec FIG. 26 is a section showing a radiant energy trans 30 tor 30 to cause axis 18 to remain directed toward a mitting means, directing light from a toroidal source. relatively moving source of radiation, as for example DETAILED DESCRIPTION the sun. In that example, a base plate 32 supports reflec tor 30 as well as the dome-shaped lens 10 and 29, via

As described in U.S. Pat. No. 4,337,759, and referring extreme outer edge portion 10a of the body means 10. A to FIG. 1, radiant energy transmitting body means 10, 35 ring gear 33 supports plate 32, and meshes with spur in the shape of a cover or dome, has multiple facets or gear 34. Drive motor 35 rotates gear 34 to controllably elements as at 11, each facet having an entry face to rotate ring gear 33, and control unit 36 controls motor receive impingement of such radiation, an exit face to 35. Unit 36 is responsive to photocells 37 and 38 in such pass energy to the exterior of the body, and an internal manner that the photocells remain directed toward the reflection face angled relative to the entry and exit faces light source. The photocells are suitably carried at 99 by to reflect radiant energy incident on the reflection face the plate 32, as for example near its periphery. toward the exit face. For example, in FIGS. 1 and 4d, a Target 15 may for example comprise a fluid recepta selected facet 11 has, in vertical cross section, an entry cle which is heat conductive, to transmitheat to fluid in face 12 made up of stair-stepped faces 12a and 12b, an the receptacle, as for example water in a pipe. exit face 13 facing the zone of target 15, and an internal 45 In FIGS. 2 and 3, the numerals 100 and 129 designate reflection face 14. Radiant energy, such as light, is rep lenses corresponding to lenses 10 and 29 described resented by rays 16a and 16b entering the body means above. They are elongated in the direction of arrow 149 10 at flat face 12a and normal thereto, and passing inter and are carried by supports indicated at 150 and 151. nally of the facet for reflection by face 14. For this V-shaped shroud 152 has edge portions 152a connected purpose, the face may be silvered at 17. The reflected 50 to the opposite edges of lens body 100, so that the rays 16c then pass toward and through exit face 13, shroud and lenses define an enclosure. A second and normal thereto, and directly toward the target zone. insulative tubular shroud 153 extends within that enclo The body means 10 may consist of solid transparent sure, about a tank 154 which has fixed (non rotatable) material, such as glass or plastic, for example. position. A support for the tank may take the form of The multiple facets 11 shown in FIG. 1 may extend 55 legs indicated at 155 and 156, bearings being provided at annularly about and define a common axis 18; or they 157 and 158 to allow tank and shroud rotation about may extend in parallel relation (normal to the plane of central axis 159, along with the lens assembly. The FIG. 1) at opposite sides of a plane as alternatively shroud 153 is cut-away at locations 160 and 161 to allow represented by 18, and which is normal to the plane of entry of radiant energy from the lens assembly, to be FIG. 1. In either event, corresponding points on the 60 absorbed by the tank, while heated air is prevented from facets define a concave surface, as for example at 21 escaping gap 162 by wipers 163; the enclosure has a (defined by the tips 22 of the facets closest the target), reflecting interior surface 152b. and characterized in that radiant energy passing Cool liquid, such as water, enters the tank via pipe through the exit faces is directed generally toward the 164, is heated therein, and discharges into the tank target zone. Tips 22 are formed at the intersections of 65 lower end at 164a. Warmed liquid slowly flows at 200 the faces 13 and 14. Surface 21 is parabolic. back up the tank, being further heated by contact with The series of facets in FIG. 1 is further characterized the exterior of pipe 164, the liquid leaving the tank at by the existence of tapered gaps 23 between adjacent outlet 165. A sacrificial anode 166 in the water 200 is

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adapted to corrode, electrolytically suppressing any pingement, about 10% for both cylinders and spheres; corrosion of the tank itself. Also, a back-up heater 167 in but the use of a thin, flexible, inflatable dome for a trans water 200 is supplied with electrical current to heat parent cover means might be worth such a loss, espe water in the tank as when solar radiation is blocked or cially since the untargeted rays would still be redirected non-existent, as at night. An air-gap may be provided at to a locus within the cover means, to assist the pressur 162 between shroud 153 and the tank itself. Sun tracking ization by heating the enclosed air. See FIG. 11 for a mechanism is indicated at 170, to rotate the assembly to non-impinging circular configuration. An alternative maintain the sun's rays incident normally toward the facet style seeks to minimize such impingement losses lenses 100 and 129, i.e., in direction 171 in FIG. 3. by concentrating the rays before they strike the TIR In operation, all radiation directed parallel to arrow 10 face, which can thereby be smaller to reduce said in 171 and striking the lenses 100 and 129 is redirected pingement. Convex and concave entry and exit faces toward the tank, as facilitated by gaps 160 and 161, to will do this, though with some decrement of the cover's heat the liquid in the tank. Also note windows 162 and concentration ratio or acceptance angle, which for 163. Wide angle, i.e., almost 180, collection of the solar some applications is far outweighed by bringing the rays is employed, as described above in FIG.1. The gap 15 transparent redirecting means even closer to the target. walls 153a are reflective, and may have other, curved For the smaller bend angles, difficulties are encoun shapes besides the straight lines shown here, for the tered in the narrowness required of the tunnels or slots purpose of secondary concentration. Stray radiation 23 in FIG. 4d forming the TIR faces of the low bend from the diffuse sources, such as skylight, is absorbed by angle elements. This can be somewhat alleviated by blackening the surface 153a of shroud 153 and of lens 20 raising the profile of the transparent means 310 above support fin at 130. the parabola 321 to widen the slots and tunnels beyond Various geometric configurations of elements and their minimum widths. Another form of such an allevia arrays of elements are possible, wherein various element tion is a backbending exit face, 311 of FIG. 5, so angled configurations have the same relative angles of the three that its refractive redirection opposes the redirection of active faces, but differing deployments within the trans 25 the TIR face, which can thereby have a greater redirec parent means; e.g., the TIR face can be in faceted slots tive bend angle with a less steep slope, giving wider on either side of the body means or on the walls of tunnels or slots.

tunnels within the latter, while the entry faces can be on In FIG. 5, note that ray 330 strikes the exit face 11 faceted steps or even on a completely smooth cover non-normally, so that ray 330a is bent back toward the surface. 30 target. This enables a wider slot 323 than if the exit face In FIG. 4a, tunnel 40 forms TIR face 41, while exit was normal and the TIR face was at a steeper angle. face 42 has stairsteps 42a and 42b. In FIG. 4b, slot 50 is The above-mentioned convex entry face will also widen on the entryside of the body means, having TIR face 51 the slots or tunnels. .

and entry face 54. Exit face 52 has stairsteps 52a and Another method of widening the slots is the faceted 52b. In FIG. 4c, tunnel 60 forms TIR face 61, and entry 35 exit face, shown in FIG. 4e. Here slot 70 has been face 62 and exit face 64 are on smooth continuous sur opened until it nearly impinges upon extreme ray 73b. faces. However, TIR face 61 must be longer than TIR Exit face 74 has miniature stairsteps 74a and 74b, respec faces 41 of FIG. 4a or 51 of FIG. 4b, because of the tively normal to and parallel to reflected ray 73b. Alter refractive bending of ray 63 by entry face 62. In general, natively, a thin, microstructured series of elements of the length of a TIR face relative to facet width 65 is: high refractive index (say n=4) can be embedded in the TIR LENGTH=cos 6/(cosm cosm) where m is the body means to form more favorably shaped elements. incident angle of ray 63a with surface normal 66, 8 The particular manufacturing method and design appli is the angle of the refracted ray 63b with 66, k the cation will determine the place of transition to a Fresnel incident angle of reflected ray 63c with exit surface lens, or alternatively to a window, that passes rays to a normal 67, and A the angle of refracted by 63d with small parabolic reflector below the target, which is 67. The relationships of these angles are given by thereby illuminated from a full circle of directions. Snell's law: sin m=n sin 8, and sin A=n sink Another possible configuration would have the outer where n is the index of refraction of the body means parts of the redirecting means sending radiant energy to material. For contiguous elements to redirect to a target a central target while the inner parts redirected energy all the parallel rays incident upon them, neighboring 50 to outer targets using only large bend angles through elements must be relatively positioned everywhere on out. All these configurations are derivatives of the basic or above a parabola with the target as its focus and a rim method of this invention; upon multiple TIR-transmit slope equal to half the rim angle (i.e., the redirective ting elements, properly placed entry, exit, and TIR bend angle of the outermost elements). faces redirect radiant energy to a predetermined target In FIG. 4d, “extreme' ray 16c must clear tip 22 of the 55 Zone, or into a predetermined target solid angle. inward adjacent facet, while the other extreme ray, 16b, Also usable is a cover means (as at 10 or 110) whose must clear top 27 of slot 23. These clearance conditions focal length can be shorter than any parabolic mirror require that the lens slope angle m be greater than or with concentrations twice as high, but which is free equal to the TER tilt angle, which is geometrically from shading and presents a convex surface with lower equivalent to tangent line 22 being on or above said aerodynamic drag than the concave parabolic mirror. parabola. Note that all of the configurations of FIG. 4 Its target is near the center of gravity and closer to the have the same bend angle a, and except for FIG. 4c the ground than that of the parabolic reflector making fixed same normal entry and exit faces. See for example the receiver means easier to design and maintain. Finally, elements 311 of the "cover' 310 in FIG. 5, above the the nearly 100% reflective efficiency of the TIR faces parabola 321 tangent to the tips 322. See also line 324. 65 give much greater potential for high efficiencies than Those tips below the parabola, such as for a quarter-cir does the parabolic mirror.

cle 325 with the same slope at the rim, would in this In FIGS. 1 and 5, it will be understood that the ele stairstep configuration suffer some interelement im ments 11 and 311 join together, integrally and continu

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ously, to form a radiant energy transmitting means in rected segments 521b falling on body 520; and second the general form of a cover. The latter has an energy arily redirected segments 521c transmitted by body 520. entry surface (top surface in FIG. 1, for example) and an FIG. 7 shows body 520 in detail, with entry faces 530, exit surface (bottom surface in FIG. 1) lying on opposite exit faces 531, and TIR faces 532. The rays 521c are sides of the cover. The cover causes radiant energy parallel, in this instance, i.e., collimated, so that means leaving the exit surface to have a generally different 520 may be regarded as a collinator. direction than the direction of energy incidence on the The means 550 shown in FIG. 14 is like 10 and 300, entry surface. Also, multiple TIR faces are situated on except that the exit faces 551 are individually angled the exit surface adjacent slots proximate the exit surface, relative to radiant energy passing through them, so as to as referred to above. The entry surface has a faceted 10 cause reflective redirection of the radiant energy. See stairstep configuration. The exit surface of the cover lies beam 552 refracted at face 551. Also in FIG. 14, the exit beyond and further from the target than a parabola (see faces 551 may be considered to refractively redirect 21 and 321). The cover may be constructed of transpar radiant energy in partial opposition to the redirection by ent material, as for example plastic, the TIR faces 553, the latter extending at less steep FIG. 8 schematically shows a means 410 correspond 15 angles (than in FIGS. 1 and 5) so as to widen the slots ing to the means 10 of FIG. 1 or 310 of FIG. 5, or 554. Note also in FIG. 14 that the entry face is smooth equivalent. A target zone is shown at 415. A retro and unfaceted, at 556, and that exit face 551 is parallel to reflector means 412 is spaced behind and facing the refracted ray 552b, giving the maximum backbend and target zone so as to redirect radiant energy upon the 20 the lowest possible slope of entry surface 556, which in target zone. See ray 413. fact is lower than the parabola 321 or the quarter-circle FIG.9 schematically shows a radiant energy source 325 in F.G. 5.

means (as for example a light source) at 430 at the target In FIG. 15, the body means 560 is like that at 10 or zone. Radiant energy emitted by the source means 430 310, except that it utilizes the variation index of refrac tion that varies with the wavelength of the radiant en is redirected by the body means 435 (like 10 or 310) in 25 ergy, reverse relation. See ray 436. so as to constitute a wavelength separating, radiat FIGS. 10a and 10b show two variations of a "uni ing energy redirecting, transmitting body means. Two bend' lens with uniform facets extending annularly apart target zones 561 and 562 are shown, and are spaced about a cylindrical target. In FIG. 10a, all the facets 444 lengthtoseparated, receive different wavelengths of the wave redirected, radiant energy. See inci of conical body means 440 bend rays 443 through 90 dent ray 563 which separates into ray 563a of one wave onto cylindrical target 441. In FIG. 10b, flat body 30 length directed toward target 561, and ray 563b of an means 445 has identical facets 448 bending rays 447 other wavelength directed toward target 562. through 45' upon cylindrical target 446. Also in FIG. 15, either target may be considered as a FIG. 11 and FIG. 11a show a structural means 460 means to convert radiant energy to electricity. One enclosing the space 461 behind the exit face of the cover 35 such means is a photovoltaic means 459 (like 10 or 310), so that pressurization of the located at the target zones in cell.FIGS. Such a device may be

atmosphere of space 461 will hold the flexible cover one target may comprise a photoillumination means means in its distended or circular shape, with center of receiving visible wavelengths; and the other target may curvature at point 426. See target zone 462, pressuriza tion means such as a pump 463 and ray 464. A thin film 40 comprise a thermal receiver receiving invisible wave lengths at zone 561.

465 adheres to the inside of cover means 459, having When a source of radiant energy is placed in zone miniature sawtooth facets 467 as shown in the insert.

FIG. 12a shows a plurality (two for example) of tar path the 562, visible wavelength rays will follow the reverse of rays 563, i.e., be collimated, while the invisible get zones 470 and 471 to receive radiant energy from longer wavelength heat rays will be diverged more the transmitting body means 472 (like 10 or 310). Each 45 outward from the visible beam, so that spotlights on element 473 redirects energy in a plurality of directions, actors toward the target zones. Thus, each element 473 may be greaterwill than not subject them to a heat load several times that of the visible radiation.

like element 10 or 310 described above but have a TIR Certain aspects of FIGS. 1-15 were also discussed in face divided into two sub-faces 474 and 475 at slightly prior U.S. Pat. No. 4,337,759.

different angles to accomplish the reflection of the two 50 FIG. 16 may be considered to correspond generally rays 476 and 477, respectively directed by the faces 474 to FIG. 4a or FIG. 4b, i.e., to present a lens body 600 and 475 toward the two target zones. having an entry face 601, a TIR face 602, and an exit In FIG.12b, TIR face 453 is the exit face for ray 451; face 603 on the body 600. Such faces 601 and 603 may while TIR face 454 is the exit face for ray 452. This be faceted, as in the styles shown in FIGS. 1,3,7,8,9, symmetrical case of twin 60' bends may be varied to 55 10, and 13. Rather than all such faces being flat, face 601 give two different right and left handbends, with differ is convexly curved, away from the body 600, as shown; ing division of the incoming radiant energy. whereas faces 602 and 603 are flat, as previously de In FIG. 13, the cover means 480 (like 10 or 310) has scribed. Diverging entry rays 605 are refracted at 605a different groups of elements redirecting radiant energy for reflection at 605b, and travel at 605c toward face toward different target zones. Thus, the elements at 603. The rays pass through exit face 603 and are in locus 481 direct radiant energy toward target 482; and general refracted to travel externally at 605d, as shown. the elements at locus 483 direct energy toward target If exit face 603 was convexly curved, then rays 605d 484. See rays 485 and 486. could be converging: The curvature of entry face 601 In FIG. 6, cover or body means 510 corresponds to eliminates the divergence and keeps any rays from miss 10 or 310 described above. A secondary radiant energy 65 ing TIR face 602.

redirecting means is provided at 520 to intercept the In FIG. 17, entry face 611 is flat, as is exit face 613; radiant energy from body 510 and to redirect it. See however, TIR face 612 is concave toward the incident rays 521 with segments 521a falling on body 510; redi ray side of that face, as shown. Diverging entry rays 615

Page 26

pass through face 611 and travel at 615a, within body Inwardly adjacent facet 704 provides three limiting 610, for reflection at 615b, at different points and angles, points that act analogously to pupils of conventional for travel at 615c toward face 613. The rays pass optical systems: tip 704t defines upper ray 701, while through that face, and are in general refracted, and travel externally at 615d, as shown. The curvature of 5 both cleared notch 704n and outer exit face 704o must be by lower ray 702. The convex curvature of the TIR face 612 has made rays 615d parallel, while entry face restricting the amount of exit face 613 that is used, en defining rays706byaccommodates assuring that the divergence of the upper ray 701 does not abling the entire lens to have a higher profile. miss TIR face 708 and that lower ray 702 does miss In FIG. 18, entry face 621 is flat, as is TIR face 622; notch 704n.

however, exit face 623 is concave away from the body 10 For the sake of diagrammatic clarity, exit face 707 is 620, i.e., away from TIR face 622, as shown. Entry rays relatively close to TIR face 708. A thicker lens with a 625, which may be parallel, pass through face 621 and travel at 625a, within body 620, for reflection at 625b at more distant exit face would employ convex curvature different points and angles, for travel at 625c toward (as on the TIR face 708c) to assure that the defining rays face 623. The rays then pass through that face and are in 15 do not miss the edges of exit face 707. If they did miss, general refracted to travel externally at 625d, as shown. they would not be lost, since they would totally inter Exit face 623 is fully flashed, as would be desirable for nally reflect on riser faces 709 or 710, and enter the lens a converging TIR lens. output with only modest angular errors. Riser face 709 Other possibilities are as follows: is angled to just clear lower ray 702 after it has left the 20 lens. Optically inactive face 711 is kept at a minimum draft angle determined by the manufacturing method flat COWSex Concave (for injection molds, it is typically 2 off the mold-pull

entry face ing direction). Face 711 assists maximizing of lens pro exit face file by enabling entry face 706 to be angled more down

TIR face X 25 ward than is the case with lens 650 of FIG. 19a, where there is a straight line between a facet tip and the notch entry face of the inwardly adjacent facet.

exit face

In summary, a unique determination of the four angu

C larities of the facet (three for its faces and one for the entry face X 30 lens profile) requires four conditions: (1) overall bend exit face angle; (2) upper ray falling on the TIR face; (3) lower TR face ray clearing notch of the inwardly adjacent face; and (4) lower ray clearing the outer edge of exit facet of the

In FIGS. 19a, 19b and 19c, the bodies 650, 660 and inwardly adjacent facet. The curvatures of the three 670 are closely similar to body 740 shown and described 35 optically mined:

active faces of the facet are individually deter in FIG. 21. The angularities of the annular facets are slightly varied, so that the body 660 produces colli of(1) entry-face curvature helps to maximize the slope the lens profile line, by allowing the tip of the in mated light rays 664; body 650 produces converging light rays at 654; and a body 670 produces diverging wardly adjacent facet to rise while keeping the higher light rays 674. The light source in each case is shown at 40 upper ray from missing the TIR face (this reduces the 680. In each case, the top surface 659, 669, and 679 of divergence of the output light of the inner facets of the the lens is circularly curved in the section shown, or lens by increasing their height above the source); spherically curved for an annular lens. (2) TIR-face curvature also helps to maximize lens In FIG. 20, lens body 700 acts as a converging TIR slope by allow the notch of the inwardly adjacent facet lens, in the same manner as lens 650 in FIG. 19a. Its 45 to rise; in addition, TIR-face curvature enables the exit performance is superior because of its full flashing, face to be fully flashed, an important characteristic for which gives more effective focusing, and higher profile, several illumination applications; and which leads to smaller angular magnification of the (3) exit-face curvature minimizes the size of the focal light source, and a smaller focal spot. Upper light ray spot of converging TIR lenses, and minimizes the beam 701 and lower light ray 702 are the defining rays for the 50 divergence of collimating TIR lenses. calculation of the angles of the boundaries of facet 703 Non-circular profiles of these curved faces may be and of the position of inwardly adjacent facet 704. The selected in order to provide uniform illumination by the slope of lens profile line 705 is to be maximized. The facet.

defining rays are generally diverging, but can come In addition, all the facets of the lens could be designed from different parts of the light source; for example, 55 to have the same size focal spot, which would then be upper ray 701 comes from the bottom of the light uniformly illuminated. This discussion of FIG. 20 may source, while lower ray 702 comes from the top of the be considered an important aspect of the invention, light source, so that they constitute the extreme rays of improving over or not suggested by, subject matter of all light emitted by the source. U.S. Pat. No. 4,337,759.

If the facet-defining upper and lower rays are not the 60 In FIG. 21, the axis of the annular, radiant energy extreme rays of the light source, then some fraction of transmitting body 740 appears at 751. The body has its output light will be redirected by the lens into the multiple annular facets 742 to 746 which are generally output rays. Such a case may occur if there is a tradeoff concentrically arranged, but having tips 742d to 746d between this fraction and the tightness of the focusing, progressively closer to plane 750 normal to axis 751. to be resolved by the particular application of the lens. 65 Face 742a of facet 742 is convex toward face 742b; and Facet 703 is defined by notch 703n (shown here as a face 742b is concave toward face 742a in the section fillet), tip 703t, upper point 703u of entry face 706, and shown. This relationship obtains for other facets, as on exit face 707, outer point 706o and inner point 706i. shown. A light-emitting diode (LED) 758 is located at

Page 27

the intersection of plane 750 with axis 751 and emits In FIG. 25, lens body 850 is the same as that of FIG. light rays toward the body 740. Ray 753 passes through 21a, except that the central refractive means has been face 742a, is refracted toward TIR face 742b and is replaced by microscope objective 854, which can slide reflected toward and passes through upper flat face 748. axially inside the lens to focus on sample 851. Charac See also ray 752 passing through face 743a, reflecting at teristic diffuse (i.e., in all directions) emission 856 from TIR face 743b, and passing through upper face 748a, sample 851 is collected by lens 850 and focused on ana angled as shown. All rays passing upwardly beyond lyzer entrance slit 852. Collimated laser beam 855 is faces 748 and 748a are collimated. The transverse width reflected by mirror 853 into objective 854 and focused of the body 740 may be from 0.12 to one inch, for exam 10 on sample 851. Mirror 853 is removable in order to use ple, and the transparent body 740 may consist of molded microscope objective 854 to view sample 851 and ex plastic material. A refractive section without facets actly adjust its position. Lens body 850 could extend appears at 719. Smaller ratios of lens diameter to LED downward below sample 851 to collect even more of size may have outermost facets large, and successively the diffuse emission. Sample 851 may be a glass capil inward facets smaller, in order to have a higher lens 5 lary containing a gas or liquid, a gold hemisphere profile and better collimation curved facets are neces coated with a sample substance, an integrated circuit on sary for. a production line (checking material composition or In FIG. 22, the radiant energy transmitting body 760 contamination), or a biological tissue sample. may have the same general construction as shown in In FIG. 26, lens body 860 has a cross-section with FIGS. 20 and 21. The lens body 760 consists of silicon, 20 axis 863, in order to accommodate toroidal (typically or a similar material, for passing infrared rays, but fluorescent) light source 861. Beneath this lamp is annu blocking visible light rays, while transmitting infrared lar involute reflector 862, with disc-shaped, planar mir rays. An arc lamp radiant energy source is shown at ror section 864 inside it and annulus mirror 865 outside 764, at the same position as the LED in FIG. 20. A it. Annular lens 866 refracts ray 868, which was re reflector surface 765 may be employed to extend in 25 flected from involute 862. Ray 869 is exactly analogous plane 766 corresponding to plane 750 in FIG. 21 with a to ray 820 in FIG. 24. Ray 867 is redirected by facet parabolic section 762. The infrared rays emanating at 870. The overall device of lamp, lens, and reflector 767 are typically collimated but may be divergent or comprise a compact floodlamp that offers much nar convergent, as in FIGS. 19a and 19c. Note that unfa rower divergence and much higher efficiency than ceted central section 770 refracts rays, as shown. The 30 possible with the prior art of reflector design. arc light source at 764 may be produced by anode and Referring again to FIG. 17, the lens is defined by TIR cathode elements 764a and 764b. Top exit surface 759 is face 612; the TIR face and one of the entry and exit circularly curved in the section shown; but the lens may faces (for example face 64) located at the opposite side have external, stairstep faceting. Protective transparent of a facet. In FIG. 16 the lens means is defined by face envelope 769 keeps outside air away from the arc. 35 601 and the TIR face at 602; and in FIG. 18 the lens In FIG. 23, the body means 780 may have the same or means is defined by the other face 623, the one face by similar construction as that of FIG. 19a, for producing 621, and TIR face by face 622. Curved face 623, in FIG. and directing convergent light at 781 into the entrance 18, can be regarded as having a cusp at its intersection end 782 of a light pipe 783. The lens has an upwardly with the lens means 623 on the next adjacent element. convex arcuate upper exit surface or face 785, an en We claim:

trance face or faces 786, and a TIR face or faces 787. 1. A radiant energy redirecting system comprising Faces 786 and 787 taper downwardly toward plane 790, a) a radiant energy transmitting body means, corresponding to plane 710 in FIG. 21. A central light b) said means comprising multiple elements, each of source 788 is positioned in the manner of the LED in which acts as a radiant energy redirecting module, FIG. 21. A planar back mirror 789 extends in plane 790 45 having on its cross-sectional perimeter an entry corresponding to plane 710 and faces upwardly. This face to receive incidence of said energy into the device may input up to 80% of the light into pipe 783, interior of said perimeter, an exit face to pass said rather than 10% of the light as via a conventional ellip energy to the exterior of said perimeter in a direc soidal reflector. tion towards the reverse side of the body from the In FIG. 24, the body means 800 may have the same or 50 side of said incidence, and a Totally internally Re similar construction as that of FIG. 21c. Circularly flecting face angled relative to said entry and exit curved top surface 801 is curved downwardly. The lens faces to redirect towards said exit face the radiant axis, in the case of an annular set of facets, is indicated energy incident from said entry face, at 802. Facets are seen from 803 to 812. A typical annu c) said body means generally redirecting incident lar facet 809 has an entrance face 809a and a TIR face 55 radiant energy towards a predetermined target 809b. Note ray 820 path passing through face 809a and Zone situated apart from and on the reverse side of face 801, and totally reflected at face 809b. In the sec said body relative to the side of said incidence, tion shown, each of the faces 809a and 809b is flat. All d) and lens means defined by said Totally Internally entry faces have draft in the direction 822, for ease of Reflecting face, molding. The lens is transparent and may consist of 60 e) the Totally Internally Reflecting face and one of molded plastic material. the entry face and exit face located at opposite sides A light source 825 is located on axis 802, and just of a facet defined by the module. above the plane 826, is within the confines of the hollow 2. The system of claim 1 wherein the Totally Inter lens, as in the above examples; and the rays 827 emanat nally Reflecting face is a body boundary, so that the ing from face 802 diverge, as in a floodlight application. 65 index of refraction “n” of the substance of said transpar The circular section half-angle subtended by the surface ent body means at said boundary gives total internal 801 is typically less than 45" and greater than 25, and is reflection of all radiant energy whose incident angle typically about 35. with the normal of said boundary at the point of inci

Page 28

dence exceeds Brewster's angle, which equals the in atmosphere of said enclosed space will help hold verse sine of the reciprocal of “n”. said cover means in said circular shape. 3. The system of claim 1 wherein said perimeters of 20. The system of combination of claim 11 wherein said elements project from said cross section to extend said entry surface is smooth and unfaceted, containing linearly, in parallel relation, said entry faces facing said 5 thereupon said individually angled entry faces, so rela incident radiant energy, said exit faces facing said target tively positioned as to smoothly be a part of said entry ZO6. surface.

4. The system of claim 1 wherein said perimeters of 21. The system of claim 1 wherein there is a plurality said elements project from said cross section to extend of target zones to receive redirected radiant energy annularly about, and define a common axis, said entry O from said transmitting body means.

faces facing said incident radiant energy, said exit faces 22. The system of claim 21 wherein each element facing said target zone. redirects radiant energy in a plurality of directions, 5. The system of claim 1 including a Fresnel lens towards said target zones.

associated with said body means and located in a mid 23. The system of claim 21 wherein different groups portion of said body means so as to redirect radiant 15 of elements redirect radiant energy towards different energy through relatively small angles toward the tar target Zones.

get Zone. 24. The system of claim 21 wherein secondary radiant 6. The system of claim 1 including a retro-reflecting energy redirecting means are provided to intercept said redirected radiant energy from said transmitting body means spaced behind and facing said target zone so as to 20 IleanS.

redirect radiant energy upon said target Zone.

7. The system of claim 1 including a radiant energy 25. The system of claim 1 wherein the entry and/or redirecting means situated at said target Zone. exit faces are individually angled relative to the radiant 8. The system of claim 1 including a radiant energy energy passing through them so as to cause refractive absorbing fluid receptacle at said target zone. redirection of said radiant energy. 9. The system of claim 8 including means to convey 25 26. The system of claim 25 wherein the radiant en relatively cool fluid into said receptacle and relatively ergy transmitting body means has an index of refraction hot fluid out of said receptacle. varying with the wavelength of said radiant energy so 10. The system of claim 8 including thermally insulat as to constitute a wavelength separating radiant energy ing means about said receptacle, said means having a 30 redirecting27. The transmitting body means.

system of combination of claim 26 wherein radiation entrance situated about said target Zone so that redirected radiant energy is absorbed by said recepta the target zones are spaced apart to receive different wavelengths of the wavelength-separated redirected cle.

11. The system of claim 1 wherein said elements join radiant 28. The energy.

system of claim 1 including means to control contiguously to form a radiant energy transmitting 35 lably tilt said body to cause said entry faces to remain cover means with an entry surface and an exit surface properly inclined relative to an angularly moving lying on opposed sides of said cover means, which source of radiant energy, such as the sun. cover means causes radiant energy leaving the exit 29. The system of claim 1 wherein said Totally Inter surface to have a generally different direction that it did nally Reflecting face is convex toward radiant energy at incidence upon said entry surface. incident thereon.

12. The system of claim 11 wherein multiple Totally 30. The system of claim 1 wherein the body means is Internally Reflecting faces are situated on facets defined annular.

by said entry surface. 31. The system of claim 1 wherein the system has 13. The system of claim 11 wherein multiple Totally multiple facets spaced at increasing lateral distances Internally Reflecting faces are situated adjacent slots. 45 from a longitudinal axis defined by said body means, proximate said exit surface. said facets having varying spacings from a plane normal 14. The system of combination of claim 13 wherein to said axis.

said exit faces refractively redirect radiant energy in partial opposition to the redirection by the Totally In and32.entry The system of claim 31 wherein one of said exit ternally Reflecting faces which lie at a less steep relative 50 other of saidfaces of each element is on a facet, and the exit and entry faces is on a surface subtend angle so as to widen said slots in said faceted exit sur ing all of the facets, said TIR face also located at the face. facet.

15. The system of claim 11 wherein the Totally Inter 33. The system of claim 32 wherein said surface is nally Reflecting faces are situated on walls adjacent concave toward said facets. voids extending within the interior of said radiant en 55 34. The system of claim 33 wherein said surface in a ergy transmitting body means. section that contains said longitudinal axis defines a 16. The system of claim 11 wherein the entry surface circular line.

has a faceted stairstep configuration.

17. The system of claim 11 wherein the outer edges of said35.circularThe system of claim 34 wherein said surface in line subtends an angle between 25 and 45.

said exit surface lie on a parabola whose geometric 60 36. The system of claim 1 wherein said facet faces focus is in the target Zone. have draft in a direction away from said surface. 18. The system of claim 11 wherein said exit surface 37. The system of claim 1 wherein said body means of said cover means lies beyond and further from the has a central portion about which said entry, exit and target than said parabola. Totally Internally Reflective faces extend, said central 19. The system of claim 11 wherein 65 portion comprising a microscope objective. a) said cover means forms a circular shape, 38. The system of claim 37 wherein said objective is b) and including structural means enclosing the space adjustably movable along an axis about which said faces behind the exit surface so that pressurization of the extend.

Page 29

39. The system of claim 1 wherein said entry, exit and 42. A radiant energy redirecting system comprising Totally Internally Reflective faces extend about an axis, a) a radiant energy transmitting body means, said Totally Internally Reflective face having curvature b) said means comprising multiple elements, each of in planes that include said axis and that intersect said which acts as a radiant energy redirecting module, faces. having on its cross-sectional perimeter an entry 40. A radiant energy redirecting system comprising face to receive incidence of said energy into the a) a radiant energy transmitting body means, interior of said perimeter, an exit face to pass said b) said means comprising multiple elements, each of energy to the exterior of said perimeter in a direc which acts as a radiant energy redirecting module, tion towards the reverse side of the body from the having on its cross-sectional perimeter an entry 10 side of said incidence, and a Totally internally Re face to receive incidence of said energy into the flecting face angled relative to said entry and exit interior of said perimeter, an exit face to pass said faces to redirect towards said exit face the radiant energy to the exterior of said perimeter in a direc energy incident from said entry face, tion towards the reverse side of the body from the c) said body means generally redirecting incident side of said incidence, and a Totally Internally 15 radiant energy towards a predetermined target Reflecting face angled relative to said entry and zone situated apart from and on the reverse side of exit faces to redirect towards said exit face the said body relative to the side of said incidence, radiant energy incident from said entry face, d) the Totally Internally Reflecting face and one of c) said body means generally redirecting incident the entry face and exit face located at oppositesides radiant energy for travel towards a predetermined 20 of a facet defined by the module, target zone situated apart from and on the reverse e) said lens means defined by said one of the entry and side of said body relative to the side of said inci exit faces.

dence, said entry faces defining a first set and said 43. The system of claim 42 wherein said entry face is exit faces defining a second set, the faces of one of convex away from said body means.

the sets being variably angled relative to one an 25 44. The system of claim 42 wherein the system has other, and with angularity that progressively in multiple facets spaced at increasing lateral distances creases for successive elements, relative to the tar from a longitudinal axis defined by said body means, get Zone, said facets having varying spacings from a plane normal d) and elements forming tapered gaps there between, to said axis.

said gaps having apices, the body being continuous 30 45. The system of claim 44 wherein one of said exit and uninterrupted everywhere along straight lines and entry faces of each element is on a facet, and the joining successive of said apices, other of said exit and entry faces is on a surface subtend e) and lens means defined by said Totally Internally ing all of the facets, said TIR face also located at the Reflecting face. facet.

41. A radiant energy redirecting system comprising 35 46. The system of claim 45 wherein said surface is a) a radiant energy transmitting body means, concave toward said facets.

b) said means comprising multiple elements, each of 47. The system of claim 46 wherein said surface in a which acts as a radiant energy redirecting module, section that contains said longitudinal axis defines a having on its cross-sectional perimeter an entry circular line.

face to receive incidence of said energy into the 48. A radiant energy redirecting system comprising interior of said perimeter, and exit face to pass said a) a radiant energy transmitting body means, energy to the exterior of said perimeter in a direc b) said means comprising multiple elements, each of tion towards the reverse side of the body from the which acts as a radiant energy redirecting module, side of said incidence, and a Totally Internally having on its cross-sectional perimeter an entry Reflecting face angled relative to said entry and 45 face to receive incidence of said energy into the exit faces to redirect towards said exit face the interior of said perimeter, an exit face to pass said radiant energy incident from said entry face, energy to the exterior of said perimeter in a direc c) said body means generally redirecting incident tion towards the reverse side of the body from the radiant energy for travel towards a predetermined side of said incidence, and a Totally internally Re target zone situated apart from and on the reverse 50 flecting face angled relative to said entry and exit side of said body relative to the side of said inci faces to redirect towards said exit face the radiant dence, said entry faces defining a first set and said energy incident from said entry face, exit faces defining a second set, the faces of one of c) said body means generally redirecting incident the sets being variably angled relative to one an radiant energy towards a predetermined target other, and with angularity that progressively in 55 zone situated apart from and on the reverse side of creases for successive elements, relative to the tar said body relative to the side of said incidence, get Zone, d) the Totally Internally Reflecting face and one of d) and elements forming tapered gaps there between, the entry face and exit face located at oppositesides said gaps having apices, the body being continuous of a facet defined by the module, and uninterrupted everywhere along straight lines e) the lens means being defined by the other of said joining successive of said apices, in planes normal entry and exit faces having for each element, a cusp to said faces, at its intersection with the lens means on the next e) said entry surface being smooth and unfaceted, adjacent element.

containing thereupon said individually angled 49. The system of claim 48 wherein said exit face is entry faces, so relatively positioned as to smoothly 65 convex toward said body means.

be a part of said entry surface, 50. The system of claim 48 wherein the system has f) and lens means defined by said Totally Internally multiple facets spaced at increasing lateral distances Reflecting face. from a longitudinal axis defined by said body means,

Page 30

said facets having varying spacings from a plane normal ing all of the facets, said TIR face also located at the facet.

to said axis. 52. The system of claim 51 wherein said surface is concave toward said facets.

51. The system of claim 50 wherein one of said exit 5 53. The system of claim 52 wherein said surface in a section that contains said longitudinal axis defines a and entry faces of each element is on a facet, and the circular line.

other of said exit and entry faces is on a surface subtend k s k k