KR100300538B1 - Tapered multi-layer lighting device - Google Patents

Abstract

The invention relates to an optical device 10 for receiving light and selectively outputting and concentrating light. The wedge layer 12 has an optical refractive index n ₁ , and the upper portion 14, the lower portion 16, and the side surface 18 cross each other to define an inclination angle. The back side 20 spans the top 14 and bottom 16 and side 18. The first layer 28 is bonded to the bottom surface 16 of the layer 12 and has a refractive index of n ₂ . The photorefractive index n ₂ of the first layer 28 causes the light input 24 to be preferentially output into the first layer 28 via the back side 20 of the layer 12. The second layer 30 is coupled to the lower portion 16 of the first layer 28 and optionally outputs light to the periphery. Additional layers such as polarizing layer 216, polarization converting layer 226 and post LCD diffusing layer 230 may be used to enable preferential use of polarized or diffused light through the LCD layer to improve the field of view of the output light. .

Description

[Name of invention]

Taper-shaped multilayer lighting device

[Brief Description of Drawings]

1 shows a wedge-shaped device of the prior art.

2a shows a multi-layer tapered illumination device constructed in accordance with the present invention.

FIG. 2B is an enlarged view of the portion of the wedge layer, the cut layers of the first and second layers combined.

FIG. 2C shows an enlarged form of FIG. 2A, showing a second enlarged cutaway layer.

FIG. 2D is a view of a portion of the coupling portion of the third layer showing the form for determining the brightness. FIG.

FIG. 2E shows a multi-layer wedge device with an inner permeable layer for redirecting light at the bottom.

2f shows a wedge device with a translucent layer on the bottom surface.

2g shows a wedge layer with a cut refractive layer on the bottom surface.

2H shows a wedge layer having a refractive layer on the bottom surface and a cut surface curved thereon.

2I shows a wedge layer with a refractive layer of cut surface with variable cutting angle.

2J shows a single refractive prism coupled to the wedge layer.

2K shows a single refractive prism coupled to the wedge layer and having an integrated lens.

2L shows the cut reflective layer bonded to the wedge device.

2M shows a cut reflective layer bonded to the wedge device with a curved cut angle.

2N shows a flat reflective cut surface on the wedge layer.

2O shows a curved reflective cut surface on the wedge layer.

Fig. 3A shows a multiple layer wedge device with a cut surface curved on the main surface side of the second layer.

3B is an enlarged partial view of the joint of the multiple layers of the wedge device.

4A shows the performance of the calculated brightness at the angle of the asymmetrical angular ranges of illumination.

4b shows the distribution performance of the calculated brightness at angles in a more symmetrical angular range.

4C is a diagram showing the brightness performance calculated at the angle of symmetry of FIG. 4B with the addition of an external diffusion element.

4D is a diagram showing a planar reflective cutting plane without parallel diffuser and an output using full-width at half-maximum brightness (FWHM) = 7 degrees.

4E shows an example of a nearly symmetrical power distribution, measured using a planar cut plane with parallel convex diffusers and a FWHM 34 degree.

4F shows an example of asymmetrical power variance measured using a curved cut plane and FWHM = 32 degrees.

4G shows an example of a curved cut plane and an asymmetrical power distribution measured using FWHM 26 degrees.

4H shows an example of two modes of output variance measured using one cut reflective layer and one cut refractive layer.

4I shows an example of output variance with large tails measured using a diffuse reflective bottom member directing layer and a refractive / inner reflective upper redirecting layer.

FIG. 5A shows a plan view of the disc-shaped light guide, and FIG. 5B shows a sectional view taken along 5B-5B of FIG. 5A.

6A shows a cross-sectional view of a multi-layer tapered lighting device including an air gap layer,

6B shows in cross section another tapered illumination device with a light source / concentrator of compound parabola.

6C shows in cross section another tapered illumination device with a variable parameter profile light source and a convex diffuser.

6D shows in cross section another tapered lighting device having a thickness of a non-forged wedge layer.

7 shows a reflective element arranged concentrically with respect to the light source.

Fig. 8 shows a reflective element arranged around the light source in a state where the center of curvature of the reflector and the center of the light source are arranged at maximum.

9A shows the use of redirection to provide a distribution of nearly similar angles radiated from all parts of the lighting device,

FIG. 9B shows the use of a redirecting layer to improve the overlap of the dispersion at selected target distances by focusing the dispersion at various angles, in particular to vary the angular dispersion emitted from other parts of the lighting device.

10 shows one form of a pair of convex arrays of a lighting device.

11 shows a convex diffusion array and a curved cutaway layer of a lighting device.

12a shows a wedge-shaped lighting device having a diffraction grating or a glog layer of one phase,

12b shows a wedge-shaped lighting device having a pair of refractive cutting surface layers and a diffuser,

12c shows a wedge shaped lighting device having a pair of cut layers,

12d shows a wedge-shaped lighting device with two refractive single cut layers,

12E shows a wedge shaped lighting device having one refractive single cut surface layer and a bottom redirecting layer,

12F shows a lighting device having a cut refractive layer and an upper surface redirecting layer of lower surface refractive and internal reflective layers,

FIG. 12G shows an illumination device having a top refracted / internal reflective cut layer and a bottom refracted / internal reflective cut layer, FIG. 12H shows an illumination with a top refracted / internal reflective cut layer and a bottom refracted / internal reflective cut layer. Showing the device,

12I shows the bottom mirror reflector and the top layer transmission diffraction grating or transmission hologram.

12J shows a lighting device having a bottom mirror reflector and a top refractive cutting layer and a diffuser.

FIG. 12K shows a lighting device with a mirror reflector in the lower layer and a refractive / internal reflective cut layer in the upper layer.

12L shows an illumination device with a lower mirror reflector and a refractive / internal reflective cut layer of an upper layer.

12m shows a lighting device having an internal reflector portion comprising an integral convex diffuser.

12N shows a lighting device with a schematic initial reflector layer portion.

12o shows an illumination device having an eccentric light coupler and focused into a wedge.

12p shows an illumination device having an eccentric light coupler and a diffuser and a schematic or convex reflector.

12q shows a lighting device having a lower mirror or a diffuse reflecting layer and an upper refractive layer,

12r shows an illumination device for generating bat wing light output.

Fig. 13 shows the combination of two integrally formed wedge parts and the use of two light sources.

14 shows a tapered disc lighting device including a cut redirecting layer.

FIG. 15 shows a lighting device operative to provide parallel light output distribution.

16A shows a prior art peripheral mode LCD,

Fig. 16B shows a transflective LCD unit of the prior art.

FIG. 17 shows a lighting device with a truncated redirecting layer and a convex diffuser operating in ambient and active modes.

FIG. 18A shows an illumination device having an array of microprisms with a cutting plane disposed over a diffused backlight, these microprisms having the same angle on both sides and each microprism having a cutting angle that changes gradually with respect to the plane;

FIG. 18B shows that in the array of microprisms shown in FIG. 18A, the sides of each microprism have a different angle that changes again with respect to the cutting plane.

19a shows a lighting device having a polarizing filter layer,

19B shows a lighting device having a plurality of layers including a polarizing filter layer,

19C shows a variation on FIG. 19B with layer refractive indices capable of outputting two polarized lights on one side of the lighting device.

20a shows a lighting device similar to that of FIG. 19b but further comprising a reflector layer,

FIG. 20B shows the same lighting device as in FIG. 20A but shows that the redirecting layer is placed on the same side of the base layer and the polarizing filter,

FIG. 20C shows a variation on FIG. 20B with a second redirecting layer and rearranged n ₂ / filter / redirecting layer.

21a shows a lighting device having a polarization converting layer and a polarization filter layer,

FIG. 21B shows a variation of FIG. 21A with a polarization filter layer and a polarization converting layer on the same side of the base layer.

FIG. 22A shows a lighting device having a polarizing filter layer on one side of the base layer and a polarization converting layer on the other side of the base layer,

FIG. 22B shows a variation on FIG. 22A with filters and conversion layers adjacent to each other on the same side of the base layer.

FIG. 22C shows a modification to the above FIGS. 22A and 22B of the reflector layer.

FIG. 22D shows a modification to FIG. 22C with the conversion layer moved to the other side of the base layer.

FIG. 22E shows another modification to FIG. 22D.

FIG. 23A shows a lighting device having a plurality of layers including a polarizing filter, a conversion layer, a redirecting layer, a reflector, and an LCD layer.

FIG. 23B shows a modification to FIG. 23A.

FIG. 23C shows another modification to FIG. 23A.

24A shows an illumination device with two polarization filter layers for two polarization states.

24B illustrates a modification in which a light redirecting layer is added to FIG. 24A.

FIG. 24C shows another variation on FIG. 24B with a matching layer, a second redirecting layer, and an LCD layer.

FIG. 24D shows another modification to FIGS. 24B and 24C.

FIG. 24E shows a variant with a second conversion layer, two polarizing filter layers and two redirecting layers relative to FIG. 24D.

FIG. 24F shows another variation of the LCD layer on both sides of the base layer with respect to FIG. 24E.

25A shows a general configuration using two polarization filter layers and a polarization conversion layer.

FIG. 25B shows a variant with a second redirecting layer relative to FIG. 25A.

FIG. 26A shows a multi-layered lighting device having a light source coupled to a light angle transformer for spatially and uniformly controlling the light output from the lighting device.

FIG. 26B shows a modification to FIG. 26A.

FIG. 27A shows a lighting device having a truncated redirecting layer, polarization, and polarization converting layer. FIG.

FIG. 27B is a variation of FIG. 27A, wherein the redirecting layer includes a reflective layer having a curved cutting plane for focusing light to a preferred viewing angle zone.

28a shows an illuminating device having a polarizing light filter, a polarizing transducer, a truncated redirecting and diffusing layer,

FIG. 28B shows a variation with two polarization filter layers and two truncated redirecting layers relative to FIG. 28A.

FIG. 28C shows a light source coupled to the lighting device, which is a modification to FIG. 28A.

FIG. 28D is a modification to FIG. 28C.

FIG. 28E is a modification to FIG. 28C.

29A shows a lighting device combining the output of polarized light with an LCD layer.

FIG. 29B is a modification to FIG. 29A.

30A shows a conventional LCD display system,

30B shows a polarization filter layer,

30C shows a multilayer thin film form of a polarizing filter,

30D shows the Brewster stack form of the polarizing filter,

30E shows the birefringent plate and interacting polarized light.

30F shows Euler angles and light vector,

30G shows a backlight providing light parallel to the xz plane,

FIG. 30H details the zone expansion from FIG. 30G.

31a shows a lighting device with a combined birefringence layer,

31B shows the lighting device and the birefringence layer and the added light redirecting layer.

FIG. 31C shows an illumination system similar to FIG. 31B but with an additional polarization converting layer.

FIG. 31D is similar to FIG. 31C but shows that the conversion layer is on the same side of the base layer as the birefringence layer.

FIG. 31E shows a modification in which the conversion layer is directly connected to the base layer in FIG. 31C.

FIG. 31F is similar to FIG. 31D but includes a layer in which the redirecting layer is cut.

FIG. 31G is based on the embodiment of FIG. 31F but includes a matching layer, an LCD layer and a diffusion layer.

FIG. 31H is a modification to FIG. 31G.

32A illustrates an illumination system including an LCD layer and a post LCD diffusion layer for processing unpolarized light,

FIG. 32B is a variation on FIG. 32A,

32C is a variation on FIG. 32B.

Detailed description of the invention

FIELD OF THE INVENTION The present invention generally relates to an illumination device that provides selected illumination, and in particular, the present invention selectively postdiffuses the light output from the liquid crystal display layer and adjusts the polarization to filter the selected polarization. By backlighting, it relates to a tapered lighting device, such as a wedge or disk, which enhances lighting and image output.

For example, various devices exist as illumination devices for liquid crystal display devices. In flat panel liquid crystal display devices, it is important to provide a suitable backlighting while maintaining a small light source. It is known to use wedge optics for general illumination purposes. Light is incident on the large end of the optics and exits from the wedge-shaped optics after internal reflection from the wedge surface until the critical angle of the reflective boundary is reached. However, since these devices were only used to transmit non-parallel illuminated outputs, the transmission of undesirable spatial and angular outputs was often done. For example, some of these devices use white painted layers as diffuse reflectors to generate non-parallel emitted light.

Therefore, it is an object of the present invention to provide an improved optical device and a method of manufacturing the same.

Another object of the present invention is to provide a new three-dimensional lighting device.

It is another object of the present invention to provide an improved multilayer tapered illumination device for optical purposes such as the use of control of polarization.

It is yet another object of the present invention to provide a new tapered illumination device for the control of the transmission and concentration of light.

Another object of the invention is to provide a novel optical device for providing collimated polarized light irradiation from the device.

Another object of the present invention is to provide an improved tapered illumination device having a polarizing filter layer.

It is yet another object of the present invention to provide a novel lighting device that allows the polarization conversion to improve the illumination output from the present invention.

It is a further object of the present invention to provide an improved illumination system that provides a combination of improved illumination over a controlled angular range in the direction of the observer using a combination of polarizing filter layer and light redirecting layer.

It is yet another object of the present invention to provide a novel illumination optics device that enhances illumination from an optical device using a combination of a polarizing filter, a polarization converting layer and a post-LCD diffusion layer.

It is still another object of the present invention to provide an improved illumination optics device in which the LCD layers are disposed adjacent to overlapping post LCD diffuser layers and can provide light distribution control over a wider angle to the viewer without loss of light output or image quality. .

Other objects, features and advantages of the present invention will be readily apparent from the following description taken in conjunction with the accompanying drawings, in which preferred embodiments of the present invention are described below.

Detailed Description of the Preferred Embodiments

A multilayer luminaire device constructed in accordance with one aspect of the present invention is shown in FIG. 2 and is generally indicated at 10. Prior art wedges 11 are shown generally in FIG. 1. In this wedge 11, the light rays in the wedge 11 reflect off the surface until the angle of incidence is less than the critical angle (sin ⁻¹ / n), where n is the refractive index of the wedge 11. Light can exit equally from both the top and bottom surfaces of the wedge 11 and also at the grazing angle.

The multilayer luminaire device 10 (hereinafter referred to as “the device 10”) shown in FIG. 2A includes a support or wedge layer 12 having a characteristic light index of refraction n ₁ . The term "wedge layer" as used herein includes all shapes having converging top and bottom surfaces with wedges in the form of cross sections. The x, y, and z axes are indicated in Figures 2A and 2C and the "y" axis is perpendicular to the paper. Typical useful materials for the wedge layer 12 are glass, polymethyl methacry1ate, polystyrene, polycarbonate, polyvinylchloride, methylmethacrylate / styrene Most transparent materials such as copolymers (NAS), and styrene / acrylo nitrile. The wedge layer 12 of FIG. 2A has a top surface 14, a bottom surface 16, side surfaces 18, an edge 26, and a back surface 20 having a thickness t _o connecting the top and bottom and side surfaces. More). A light source, such as tubular fluorescent light 22, introduces light 24 through the back side 20 into the wedge layer 12. Light 24 is intentionally reflected from the various wedge layer faces towards the edge 26 along the wedge layer 12. Other possible light sources can be used and will be described below. In general, conventional light sources are substantially disturbed and provide uncollimated light, but aggregated and collimated light can be processed by the present invention.

In the case where the faces 14 and 16 are flat, a single tilt angle φ with respect to the linear wedge is defined by the top face 14 and the bottom face 16. In the case of a nonlinear wedge, a continuous angle Φ can be defined, and the nonlinear wedge can be designed to provide control of the desired light output or condensation. Such nonlinear wedges will be described in more detail below.

In FIG. 2A, the first layer 28 is coupled to the gap layer 12 without any air gap, and the first layer 28 has an optical index of refraction of n ₂ and is optically connected to the bottom surface 16. . The first layer 28 can range from a light wavelength of constant thickness to a much larger thickness to achieve the desired function. The final dielectric interface between wedge layer 12 and first layer 28 has a higher critical angle than at the interface between wedge layer 12 and the ambient atmosphere. As will be clarified below, this feature allows for the optional angular output and collimation of the light 24 from the device 10.

In some embodiments, greater than n ₂ , a second layer 30 having an optical index of refraction n ₃ , preferably greater than n ₁ , is connected to the first layer 28. This configuration allows light 24 to leave first layer 28 and enter second layer 30. In the embodiment of FIG. 2A, there is substantially no air gap between the first layer 28 and the second layer. In a preferred form of the invention shown in FIG. 2A, n ₁ is about 1.51 n ₂ <1.5 and n ₃ ≧ n ₁ . Most preferably, n ₁ = 1.5, n ₂ <1.5 (approximately equal to 1) and n ₃ ≧ n ₁ .

In the multilayer configuration for the device 10 shown in FIG. 2, the wedge layer 12 has an angle of incidence 2 ° in relation to the normal of the plane of the bottom surface 16 during the periodic time of each reflection from the top surface 14. Decrease by. When the angle of incidence with the bottom surface 16 is less than the critical angle characteristic of the interface between the wedge layer 12 and the first layer 28, light 24 is coupled to the first layer 28. Therefore, the first layer 28 and associated light interface properties form an angular filter that allows light 24 to pass when the condition θ <θ _c = sin ^-1 (n ₂ / n ₁ ) is satisfied. do. That is, the critical angle described is higher than for the interface between air and the wedge layer 12. Therefore, if the two critical angles differ by more than 6Φ, then almost all of the light 24 is wedge layer 12 and first layer 28 before it can exit wedge layer 12 through top surface 14. Will cross the boundary between them. Thus, if the two critical angles differ by less than Φ, a substantial minute portion of the light (smaller than half) may exit wedge layer 12 through top surface 14. If the two angles differ by more than Φ but less than 6Φ, a substantially less than half, but less than all, amount of light may pass through the wedge layer 12 and the first layer 28 before exiting through the top surface 14. Will cross. Thus, the device 10 may be configured such that the condition θ <θ _c is first satisfied for the bottom surface 16. Next, escape light 24 (light entering the layer 28) will enter the second layer 30 as long as n ₃ &gt; n ₂ , for example. Light 24 is then provided by first layer 28 connected to wedge layer 12 and becomes collimated light 25 in second layer 30 having an appropriate relationship between refractive indices.

In order to generate an output 24 of light from the device 10, the second layer 30 is light such as the paint layer 33 shown in FIG. 2E or the opposing surface 34 shown in both FIGS. 2B and 3C. Means for scattering. Paint layer 33 may be used to selectively project images or other visual information. The waste layer 33 may contain, for example, particles that are controllably distributed having a refractive index.

By appropriate choice, light can also be redirected through the wedge layer 12 to the atmosphere (see light 29 of FIGS. 2A and 2C) or output directly from the second layer 30 to the atmosphere (of FIG. 2F). Optical 29 ').

In other forms of the invention, there may be multiple other layers associated with the "n" value. In one preferred embodiment of the present invention, the exponent of the lowest exponent layer can replace n ₂ in the equation for the numerical aperture and the output angle (to be described later). These other layers may be interposed, for example, between the wedge layer 12 and the first layer 28, between the first layer 28 and the second layer 30, or the wedge layer 12 or the second layer. It may be an upper layer of layer 30.

In certain embodiments, good geometry causes light to be output to the atmosphere without being reflected back through the wedge layer 12. In another form of this embodiment, shown in FIG. 2G, a refractive layer 38 is shown. Refractive layer 38 may include a flat surface 39 to provide collimated output. A horizontal axis lenticular scatterer 83 is shown in Fig. 2G, which is described in detail below. Scattering layer 83 can be used with any geometry of the present invention, including the wedge layer 12 as shown in FIG. 6A.

In another example, shown in FIG. 2H, the refractive layer 38 may include a curved face 41 to provide an output that is smoothly widened through the desired angular distribution. In another example shown in FIG. 21, refractive layer 38 includes various facets 42. These faces 42 have facets and / or bends that vary with position across the face array to focus the output light in a desired manner. The curved surface can create a smoothly focused area and reveals the entire field of view screen to be illuminated within this area. An application example for computer screen illumination is described. 2J and 2K, a single refractive prism element 43 and a prism element 43 with an integral lens are shown, respectively, for condensing output light.

2L and 2M show a face surface 34 with faces angled and arranged to control the output distribution of light.

In FIGS. 2K and 2L, light is output at focal point “F” and is output through approximately the viewing range 45 in FIG. 2M. 2N and 2O have a reflecting surface 48 and a curved reflecting surface 45 for providing collimated light output or focused light output, respectively.

As shown in FIGS. 2A and 2C, the surface surface 34 optically reflects light 29 through the second layer 30, the first layer 28, and the wedge layer 12 and redirects it to the atmosphere. . If only the refraction of each face is illuminated, the output will alternately appear bright and dark when viewed on a very small scale. Since this pattern is typically not desirable, in the preferred embodiment shown in FIG. 2B, the period of spacing between each of the surface surfaces 34 is large enough to avoid the diffraction effect, but each surface is intended to observe. Small enough not to be detected by The spacing is also chosen to avoid forming a Moire interference pattern with any characteristics of the device to be illuminated, such as a liquid crystal display or CCD (charge coupled device) array. Some irregularities in the spacing can reduce undesirable diffraction moire effects. In a typical black illumination display, interval periods of approximately 0.001-0.003 inches can achieve the desired purpose.

2B and 2C surface surface 34 may be prepared, for example, to control the angular range from which reflected light 29 is typically output from device 10. The minimum distribution of the output angle of the layer 30 has a width approximately equal to Δθ = 2Ψ) [n ₁ ² -n ₂ ² ) / (n ₃ ² -n ₂ ² )] ^1/2 .

Thus, since Ψ can be very small, the device 10 can be a very effective collimator. Thus, for linear plane surface 34, the excitation redirected light 29 is approximately Δθ air = n ₃ Δθ = 2Ψ) (n ₁ ² -n ₂ ² ) / [1- (n ₂ / n ₃ ) ² ] has a minimum angular width of about ^1/2 . As described above, and as shown in FIGS. 2h 2i 2k 2l 2m and 3, the plane geometry exceeds each minimum angle to control each output and also to focus and control the output light. Can be used.

Although various interface output angles may be extended beyond the values given above, this effect can be alleviated by applying an antireflective coating 31 on one or more internal interfaces as shown in FIG. 2B.

The brightness ratio ("BR") of the described embodiment can be determined by reference to FIG. 2D as well as by an etendue match, where BR is Or BR = lighted area / total area.

BR = [1- (n ₂ / n ₃ ) ² ] ^1/2 = 0.4-0.65 (almost transparent dielectric material). For example, the wedge layer 12 may be acrylic (n ₁ = 1.49) and the first layer 28 may be a fluoropolymer (n ₂ = 1.28-1.43) or a Sol-gel (n ₂ = 1.05-1.35). , Fluoride salt (n ₂ = 1.38-1.43) or silicone-based polymer or adhesive (n ₂ = 1.4-1.45), and the second layer 30 is a polycarbonate (n ₃ = 1.59) metalized at the air contacting surface. Polystyrene (n ₃ = 1.59) may be a surface reflector such as foxy (n ₃ = 1.5-1.55) or acrylic (n ₃ = 1.49).

For example, the flat or linear planar surface 34 shown in FIGS. 2B and 2C controls the direction of light output and also accounts for the angular distribution of light Δ θ coupled to the second layer 30 by the angular filtering effect. The incident light 24 can be redirected for near integrity (see, eg, FIG. 4D). For example, in one preferred embodiment shown in FIG. 2L, the surface surface 34 reflects light using a flat surface angle that varies with position to focus the output light.

In FIG. 2M, the surface surface 34 includes a curved surface angle that varies with position to create a focused viewing zone 45 in which the entire screen to be illuminated appears (see, eg, FIGS. 4F and 4G). Also shown is an exemplary liquid crystal display 47 usable in connection with the present invention in the model of FIG. 2M. As also shown in FIGS. 3A and 3B, the curved surface 36 also redirects the incident light 29, but the curved surface increases the final range of each output of the redirected light 29 (FIG. 2D). Comparison with flat surfaces). For example, it is known that a concave trough can produce a real image, and a convex through can generate a virtual image (see for example FIG. 3B). In each case, the image is like a line source that emits light evenly through each desired output range. Thus, such an array of trough-shaped faces 36 can redirect the inflow of collimated light 25 from the first layer 28, and the plurality of line source images can redirect the redirected light 29. Form. By arranging at intervals of the curved surface 36 smaller than the resolution of the human eye, the final array of line sources will appear very uniform to the viewer. As previously described, a selection of about 300 to 500 lines / inch or 0.002 to 0.003 for the period of face spacing provides this result. In the case of a typical LCD display, it was conventionally about 20 inches or more.

Other useful face shapes may include, for example, parabolas, ellipses, hyperbolas, circles, exponents, polynomials, polygons, and combinations thereof. Thus, the user can construct a virtually arbitrary distribution of the average ballics of illumination using different face designs.

For example, a polygonal face can be used to generate an output angular distribution with multiple peaks.

Examples of brightness distributions over various ranges of each output using curved surface reflectors are shown in FIGS. 4A-4C, 4F and 4G. 4C and 4E show the brightness distribution in the case of a reflector having a linear plane, and further include a scattering element 40 (shown in phantom in FIG. 2C). Predicted performance outputs for the various angular ranges are shown (see FIGS. 4A-4C), and these outputs correspond to the Wedge LiHot unit, a trademark of Display Engineering. It is compared to the measured angular output of light for the same commercially available source (labeled "wedge"). The preferred angular range is easily modified to accommodate any specific viewing and collimation requirements up to the lowest angle Δθ (air) described below in the equations Ψ, n ₁ , n ₂ , n ₃ . have. This modification can be accomplished by gradually changing the curvature of the curved facets 36 in the manner described below and shown in FIG. 2M. In addition to the illustrated control of the vertical viewing angle range, modification of the horizontal viewing range can also be achieved by appropriately changing the shape of the curved facets 36. The angular distributions described above in FIGS. 4A-4I are characterized in that the device 10 processes light 24 within a numerical apperture NA (n _l ² -n ₂ ² ) ^1/2 . Indicates when. When light is outside this range, additional techniques may be applied to help control each output range.

9A and 9B further illustrate the use of redirecting means to provide tightly overlapping focused illumination output and loose overlapping, respectively. This concept can be practically applied by considering that a typical portable computer screen 87 has a vertical extent (V) of approximately 150 mm and a typical viewing distance "D" is 500 mm. At a distance "D" located at the normal of the vertical center of the computer screen 87, the observer angles from -8.5 squares measured at the top of the screen 87 to +8.5 measured at the bottom of the screen 87. Will represent another area of the screen 87. However, this deviation in viewing angle can lead to undesirable effects in the use of the system with the screen illumination. The limited angle of illumination for the screen 87 means a limited range of locations from which the viewer can fully see the illuminated screen 87 (see FIG. 9A). By defining the observer position with respect to the angle and distance from the center of the screen 87, the effective angle range is substantially reduced below the nominal illumination range. For example, if the nominal illumination range is ± 12 ° measured at each individual facet, the effective viewing angle is reduced to ± 12 ° in the conventional flat panel shown in FIG. 9A. The resulting illumination between 12 ° -20 ° on either side of the center to the screen 87 will appear non-uniform to the viewer.

The invention described herein can be used to overcome the non-uniformity described above by controlling the orientation of the burr 34. For example, as illustrated in FIG. 2M, as both faces of the face gradually rotate, from 35.6 ° to 33.3 ° with respect to the edge of the face where the flat facet surface defines several layers of the device 10. Change or become parallel. This system atic variation from the top to the bottom of the screen 87 results in the illumination of the redirected output. The end 34 may be combined with a diffuser 83 or the like to generate a variable but controllable distribution of light illumination output. The flat surface 168 may be further combined with the diffuser 170. Thus, as shown in FIG. 9B, the ability to rotate the angular distribution of light at different points on the screen 89 makes it possible to compensate for variations in the viewing angle depending on location. The organizational change in the face 34 further includes a change into focus, which is the output of any faceted redirecting layer. Examples are shown in FIGS. 2I and 2L.

In another embodiment to overcome non-uniformity of illumination, the micro-prism array for the face 34 may be placed over a conventional diffuse backlight 101 (see FIG. 18A). This face 34 is operated by a combination of refraction and total internal reflection such that only a limited angular range is output to the atmosphere through the layer. This angle range depends on the facet angle. In the case of an acrylic film (n = 1.49), the highest brightness is usually obtained using a prism containing an angle of 90-100 degrees, which is represented by an observation angle of approximately ± 35 degrees. Backlights using this combination geometry have a sharp "curtaining" effect that confuses multiple observers. This effect can be improved by rotating the surface 38 from the top to the bottom of the screen to produce a focusing effect (see FIG. 18B). A simple ray-tracing will generate an angle distribution that rotates about 3/2 for a horseboard that is rotated 3 degrees for an included angle in the range of 100 ° to 110 °. In the embodiment shown in FIG. 18, the gradual change in facet face angle may change as a position along the face 34. E.g,

Ψ ₁ = 35˚- (0.133˚ / mm) * x

Ψ ₂ = 35˚ + (0.133˚ / mm) * x

This gradual facet angle change varies approximately 10 degrees across screen 89, resulting in an angular distribution that satisfies the generic constraints outlined above.

Whatever the preferred surface shape is, the surface 34 (see FIG. 2D) is preferably formed by conventional processing such as molding or other known milling processes. The detail about manufacture is demonstrated.

[Nonlinear Wedges]

In another aspect of the invention, the wedge layer 12, which is the primary lightguide, may be other than assumed to be linear. These shapes make it possible to achieve various selective light distributions. Other shapes can be described with respect to the thickness of the wedge layer 12 as a function of the wedge axis “Z” shown in FIGS. 2B and 2C (the coordinate axis from the light input edge to the slightly sharp edge 26). For linear wedges

A (z) = A _o -C

A ₀ = maximum wedge thickness (see FIG. 2A)

C = constant = tanψ (1)

A large range of desirable spatial angular distributions can be obtained with light output power (power connected to the second layer 30). Thus, this light output power is light available for output to the outside air by means of a suitably small faced surface (surface 34 or 35) or by a diffuse reflector 33 (see FIG. 2E) or other means.

For example, if L and M are cosine directions along the x and y axes, respectively, L _o and M _o are the values of L and M at the thick edge (Z = 0). This initial distribution is Lambert within an angular range that is somewhat well defined, with little or no light outside that range. This distribution is particularly important because ideal non-imaging optical elements have a defined Lambert output distribution. The key relationship is approximately the same as A _o L _o and A (z) cos (θ _c ), an invariant adiabatic invariant that implicitly provides the escape position z. To illustrate this concept, suppose we want uniform irradiation so that dp / dz is constant. Assume that the initial phase space uniformly fills the elliptic region described by the following expression.

L ₀ ² / σ ² + M ₀ ² / τ ² = 1 (2)

Where τ is the dimension of the ellipse along the M axis and σ is the dimension of the ellipse along L.

Next, dP / dL = const · [1 − L ² / σ ² ] ^1/2 but dA / dZ [A _o / L _c ] dL _o / d _z where L _c = cosθ _c . Therefore, "1-(L _c A) ² / (A _o σ) ² ] ^1/2 dA = constant time dz. Let σ = L _c in the preferred embodiment. This result is substituted by A / A _o = sin u, so A = A _o sin u and u + 1/2 sin (2u) = (π / 2) (1-z / D), where D is a wedge The length of layer 12.

More generally, if the desired power per unit length is dP / dz, the shape of the desired wedge layer 12 is determined by the following differential equation:

It is noteworthy that in all these cases the power distribution is roughly desired because it is deformed by Fresnel reflections. Even if the wedge device 10 is curved, it may still be useful to define an average angle Ψ if its curvature is not too large, which averages the quality of the system.

In another aspect of the invention, the structure of the above example has an x, y contact surface between two reflective media having indices n1 and n2. Components nM, nN are maintained across the contact surface such that n ₁ M ₁ = n ₂ M ₂ , n ₁ N ₁ = n ₂ N ₂ . The incident angle projected on the x, y plane is given by sinθ _2eff = N / (L ² -N ² ) ^1/2 . Using this relationship, _{Sinθ 2eff} / _{Sinθ 1eff} = (n ₁ / n ₂ ) [1-M ₁ ² ] ^1/2 / [1- (n ₁ / n ₂ ) ² M ₁ ² ) ^{l / 2} = ( n ₁ / n ₂ ) _eff . For example, for n ₁ = 1.49, n ₂ = 1.35, M ₁ = 0.5, the effective index ratio is 1.035 (n ₁ / n ₂ ), which is only slightly larger than the actual index ratio.

[Change of reflectance according to spatial parameter]

In the case of a typical tapered light guide, the wedge layer 12 is narrow along the x axis and along the z axis (see, eg, FIG. 2A). When L, M, and N introduce optical direction cosines (nL, nM, nN), which are structural direction cosines along the x, y, and z axes, n is a refractive index that can vary depending on the spatial position. In the case of light rays transmitted to the wedge layer 12, the movement on the x side is almost periodic, and the amount of Ψ nLdx per cycle is nearly constant as the light propagates along z. It is almost constant as it propagates. This feature is called adiabatic invariance and provides a useful structure for analyzing light guiding properties.

In the first embodiment, the wedge device 10 shown in FIG. 2A has a uniform index in the wedge layer 12, has a width A (z) A _o -Cz and z is tapered linearly. Thereafter, L (z) A (z) becomes approximately constant due to adiabatic constant along the zigzag ray path. When L = L _o and the ray starts at z = 0, (A _o -C · z) L (z) becomes approximately equal to L _o A _o . L = cosθ _c where θ _c is the critical angle = [1- (n ₂ / n ₁ ) ² ] ^1/2 where light rays leak out of the wedge layer 12. Therefore, the conditions for leaving the wedge layer 12 are A _o -C · z = L _o A _o / cosθ _c . This occurs at z = (A _o / C) (1-L _o / cosθ _c ). As a result, the ray density radiated on the z axis is proportional to the density of the ray in the initial direction cosine L _o . For example, the density becomes uniform when the initial distribution of L _o is uniform.

In the second embodiment, the index profile is no longer uniform and is reduced in both the x and z axes. If the degree of reduction in the z-axis is slower than in the x-axis, the ray path is still almost periodic and the adiabatic invariant still applies. As ray 24 propagates along the z-axis, the path in the x, nL space is nearly periodic. Therefore, the maximum of L (z) increases, and some z may reach a threshold for leakage. The z value for leakage depends on the index (n) profile. If this is specified, the analysis proceeds as in the embodiment described above. Thus, for a parabolic index profile, the index profile is -p <xp = n ₁ ² = n ² ₀ [1-2Δ] where | x |> p) n ² (x) = n ² ₀ [ 1-2Δ (x / p) ² ] form. The critical angle at x = 0 is still given by sin ² θ _c = 2Δ = 1− (n ₁ / n ₀ ) ² . If we have n ₀ , the slowly decreasing function of z, the slope θ at x = 0, is slowly increased by the adiabatic instability of Ψ nLdx, and θ _c is decreased, resulting in light leakage. The ray distribution depends on how the index n varies with z.

[Non-Wedge Tapered Structure]

In the most common case, light can be incident on any type of layer (eg, parallelepiped, cylindrical or non-uniform wedge), and the principles described herein apply in the same way. In addition, the refractive index changes as desired in (x, y, z) to reach the proper final result when coupled to the means for outputting light externally.

For example, consider a disc shaped light guide 46 tapering in the radial direction r shown in FIG. 5. Directional cosines in the cylindrical polar coordinates are kr, ke and kz. The light 48 delivered to this light guide 46 satisfies the following relationship:

Φkn _z dz-constant (insulation constant) (4)

nrk _θ = constant (angular momentum conservation) (5)

The adiabatic constant conditions are the same as for the wedge device 10, and the previous discussion with the wedge device 10 applies to the light guide 46. In each kinetic preservation condition, the kθ value needs to be reduced when light is emitted from the source 47 to the outside as the radius is increased. Therefore, light is collimated in the direction of increasing radius. This results in a fundamentally similar feature to the wedge device 10 and allows the light 48 to exit the light 52 at a predetermined angle with the surface collimated along the z direction.

For illustration purposes, we used a guide material with a constant refractive index. For such a structure, the light rays 48 along the bidirectional cross-section cut along the lines 5B-5B act as in the case of the wedge device 10 corresponding to that described above. Similarly, various additional layers 54 and 56 and other means can be used to achieve the desired light adjusting characteristics. For example, in the case of the disc light guide 46, the preferred face array 56 is a series of circles concentric with the disc 46. Thus, if the cross-section of the face 56 is linear, then the ray 52 emerges in a direction collimating the function of refractive index within a total angle of 2Ψ as in the device 10 described above.

[Tapered Light Emitting Device with Two Layers of Low Index]

In another form of the invention shown in FIG. 6A, the device 10 comprises a first layer 61 having an optical index of refraction n ₁ and a first or upper layer surface 62 condensed to set at least one inclination angle Ψ and A second or lower layer surface 64. The first layer 61 also includes a back surface 65 that leads to the upper layer surface 62 and the lower layer surface 64.

Adjacent to the first layer 61, there are layer means, such as bottom transparent layer means, such as the first intermediate layer 66, which is disposed adjacent or below the lower layer surface 64 and has a refractive index n ₂ . In addition, the layer means are upper transparent layer means and can implement a second intermediate layer 81 of refractive index n ₂ disposed adjacent the upper layer surface 62. One of layers 66 and 81 may be at least an air gap or another gas or transparent dielectric gap.

Air gaps may be established by conventional means, such as external support such as supporting a layer upon stretching (not shown) or disposing a spacer 68 between the first layer 61 and the adjacent light redirecting layer 70. have. Similarly, a spacer 68 may be positioned between the first layer 61 and the second light redirecting layer 70. Otherwise, a solid material can be used in the transparent dielectric for constructing the layers 66 and 81 and can be improved to be structurally complete, strong and easy to assemble. Such solid materials include, for example, sol-gel (n ₂ = 1.05-1.35), flopolymer (n ₂ = 1.28-1.43), prolide salt (n ₂ = 1.38-1.43) or silicon-based polymers and adhesives ( n ₂ = 1.40-1.45). Such solid materials for transparent dielectrics do not need to separate the means for supporting or retaining them, and the NA acceptability is lower because the index is higher than in the case of air gaps.

Layers 66 and 81 transmit light incident from the first layer 61. In this embodiment, some of the light achieves θ _c with respect to the upper layer surface 62, and the light is incident on the layer 81 and processed again by the light redirecting layer 82. The remaining light achieves [theta] _c with respect to the lower layer surface 64, and therefore enters the layer 66 and is processed again by the light redirecting layer 70.

In a preferred embodiment of the present invention (see FIG. 6A), both layers 66 and 81 are present and have similar but significantly different indices n _2a and n _2b , respectively. The index is considered similar when setting thresholds at contact surfaces 62 and 64 that are similar in size to the wedge angle Ψ. E.g,

| arcsin (n _2a / n ₁ ) -arcsin (n _2b / n ₁ ) | <6Ψ (6)

In this case, important portions (but not identical) of light are incident into each layer 66 and 81 and subsequently processed by the redirecting layers 70 and 82 respectively. A larger portion enters into the larger layer of the two refractive indices n _2a and n _2b . The redirecting layer 70 processes only the fragments entering the layer 66. Therefore, the influence of the redirecting layer 70 on the output angular distribution of light can be changed by varying the relationship between the refractive indices n _2a and n _2b .

In another preferred embodiment of the present invention, layers 66 and 81 may be the same transparent material having a refractive index n ₂ <n ₁ . In general, a small value of n ₂ increases the numerical aperture at the light incident surface, thereby improving the efficiency of the device 10. Therefore, the light collection efficiency can be maximized when the layers 66 and 81 are gaps filled with air or other gas (where n ₂ = 1-1.01).

The thicknesses of layers 66 and 81 can be optionally changed to control the output power spatial distribution of device 10 or to improve its visual uniformity. For example, increasing the thickness of layer 81 by 0.002 "-0.030" significantly reduces non-uniformity, which tends to appear at the thick end of device 10. The thicknesses of layers 66 and 81 may vary gently with position to affect the desired spatial distribution of the light output (see FIG. 12L).

In a preferred form of the invention shown in FIG. 6A, the light redirecting layer 70 includes a reflective layer 71 that reflects light through the layer 66 and the first layer 61. Light is output through the upper surface 62 and eventually through the light redirecting layer 82 to the first layer 61 for subsequent processing. Reflective layer 71 may be, for example, a combination of a planar mirror reflector, a partial or total divergent reflector, a faceted reflector, or a polyhedral reflector.

Using a flat mirror reflector. The angular distribution in layer 81 is the narrowest. Therefore, a planar mirror reflector can be used in the design of the light redirecting layer 82 when the desired output angle distribution is monolithic. The diverging reflector or the specular reflector can be used for the layer 71 to achieve a wide range of angular dispersion (see FIGS. 4H and 4I) or to improve the uniformity (see FIG. 4N). Is preferred if has a wide “tails” (see, in particular, FIG. 4I). The reflector may produce a dual shape angular distribution in layer 81 (see FIG. 4H). Therefore, the specular reflector described above is preferred when the desired output angular distribution is of dual form. For example, the bimodal “batwing” distribution is preferred for indoor lighting illuminators because it reduces glare.

In general, the angular surface of layer 71 can be made into a shape capable of controlling the angular distribution of light reflected through layer 66 and first layer 61 for subsequent processing by redirecting layer 82. have. The angle distribution in the device 10 affects the angular distribution of light output from the redirecting layer 82 to the periphery. For example, curved curved surfaces can be used to smoothly expand the angular distribution while providing divergence effects to improve uniformity. The reflective layer 71 may affect the output power spatial distribution and the angular distribution. The reflectivity, specular reflectivity, and geometry of the reflective layer 71 may vary with location to achieve the desired output distribution. For example, as described above, if the inclination of each component of the reflective layer 71 is slightly varied as a function of position, the light output distribution fluctuates significantly.

The light redirecting layer 82 has a refractive index n ₃ > n ₂ and is substantially transparent or translucent. Light in the low index layer 81 enters layer 82 and is redirected towards the periphery. The transmissive redirecting layer 82 is also processed by the reflection of the redirecting layer 71 and then redirects the light transmitted back through the low refractive index layer 66 and the first layer 61. The permeability and geometry of layer 82 may vary with location to affect the output spatial distribution of device 10. In a preferred form of the invention, the redirecting layer 82 comprises a polyhedralized surface in contact with the low refractive index layer 81 as shown in FIG. 6A. Light entering the layer 82 is refracted at one side 84 of the angled face 85 and then totally internally reflected at the second side 86 of each face 85. In one aspect of the invention, the redirecting layer 82 may be made of "Transparent Right-Angle Film" (hereinafter TRAF), a trademark of 3M Corporation sold by 3M Corporation. TRAF operates to redirect the incident light approximately 90 degrees through refraction and total internal reflection, which is desirable in typical LCD backlight applications. The allowable angle of the prior art TRAF is about 21 degrees, which is sufficient to redirect a large portion of the light incident on the low refractive index layer 81. In a further preferred form of the invention, the angle is selected to redirect more of the light 75 incident on the low index of refraction layer 81 through a mechanism that adds total internal reflection to the aforementioned refraction. The corrugated surfaces 84 and 86 or one of them can be made into a shape that can control the output angular distribution. For example, curved curved surfaces can be used to smoothly expand the distribution while providing a light divergence effect to improve uniformity.

In another preferred embodiment, the angular surface of the redirection layer 82 may be gradually varied to compensate for variations in viewing angle depending on location when viewed at typical viewing distances. This compensation effect has been described above with reference to the design of the reflective masking layer in the embodiment shown in FIG. 2M. Similar principles can be applied to the design of any faceted redirecting layer, including refractive layers and refractive / inner-reflective layers. Embodiments in which such progressively varying polyhedralized layers can be used are described, for example, in FIGS. 12E (layer 140), FIG. 12G (layer 152), FIG. 12H (layer 166), FIG. 12K (layer 186), FIG. 12n (layer 210), FIG. 12O (layer 228), and FIG. 12P (layer 246).

In another form of the invention, layers 66 and 81 may have similar but slightly different refractive indices n ₂ and n ₂ ′, respectively. If the critical angle associated with the contact surface between the first layer 61 and the two layers 66 and 81 does not differ by more than the first layer convergence angle, the operating principle of the device 10 is substantially similar.

| arcsin (n ₂ '/ n _l ) -arcsin (n ₂ / n ₁ ) | <Ψ (7)

In this case, therefore, light of substantially the same portion is incident on layers 66 and 81 and subsequently processed in redirecting layers 70 and 82, respectively.

All forms of the invention may further include an output diverging layer 40 shown in dashed lines in FIG. 2C or a transmissive or translucent diverging layer 83 shown in FIG. 6A. In general, the diverging layer 40 may be a surface diverger, a volume diverter, or at least one micro lens array (also known as a “lenticular array”) having at least a portion of a cylinder. The layers 40 and 83 can increase light uniformity or extend the angular distribution around. Lenticular arrays are more beneficial because they have less back-scattering than surface or volume diverters and have sharp output angle cut-off when irradiated by collimating rays. The lenticular array preferentially diverges only portions to travel in the axial direction of each cylindrical micro lens.

In the preferred embodiment shown in FIG. 10, the light redirecting layer 10 uses a flat mask surface 111 so that the output light is highly collimated. The desired output angular distribution can be further controlled by including a lenticular diverter 112 having an appropriate aperture ratio and whose cylinder-type microlenses travel approximately parallel to the y-axis. The lenticular diverter 112 generally emits non-uniformity to travel in the y-axis direction. In this embodiment, a second lenticular diffuser 113 may be included to dissipate non-uniformity that would generally travel in the z-direction. The microlenses of the second lenticular emitter travel approximately parallel to the z-axis (see FIGS. 12H and 12N). The order of positioning of the emitters 112 and 112 can be interchanged without compromising the optical advantage. Similarly, lenticular diverges 112 and 113 may be inverted and concave instead of convex as shown in FIG. 10. Although this change may affect detailed performance, the diverging layers 112 and 113 may still provide the general benefits described above.

In another embodiment shown in FIG. 11, the functionality of both the flat-faceted light redirecting layer (110) and the parallel lenticular diffuser (112) in FIG. Can be performed by the light direction correcting layer 114 with curved surfaces (see, for example, FIGS. 2H, 2M and 3A showing curved surfaces). These curved surface layers control the angle output by modifying the direction of light, having the appropriate surface curvature, and serve as diffusers for non-uniform progression in the general direction of the y axis. By combining these functions within a single layer, many of the components can be reduced, improving thickness, cost and manufacturing efficiency. In this embodiment, a single lenticular diffuser 115 may be included to spread the residual non-uniformity that would otherwise proceed in the normal z-axis direction without the single lenticular diffuser 115. This type of lenticular diffuser microlens runs approximately parallel to the z axis. It should be noted that the lenticular diffuser 115 may be inverted to have a concave curvature rather than the convex curvature shown in FIG. 10. While these changes may affect performance, the layers at 114 and 115 intentionally perform these changes.

In all embodiments using multiple microstructured layers, the facets or lenslet spacings of these layers described above can be selected with a liquid crystal display to have an unreasonable ratio to prevent undesired MAR interactions between the layers. have.

Similar lenticular diffusers are used with non-wedge shaped geometries with wedge (wedge) cross action, providing similar advantages when the diffuser cross-sections are approximately as shown in FIGS. 10 and 11. One example is the tapered disc shown in FIG. In this case, a lenticular diffuser similar to layer 112 in FIG. 10 will have a micro lens whose axes move in concentric circles around the disk rotation axis. A diffuser similar to layer 113 in FIG. 10 and layer 115 in FIG. 11 will have micro lenses whose axes radiate radially from the center side of the disc.

[Light source and coupler]

In a more preferred form of the invention shown in FIGS. 2A and 2B, a masking layer 30 has been included to optically modify the direction of light. The floors 34 may be a floor layer that is joined to or separated from the layer. The detailed operation of this masking layer has been described above. As shown in FIG. 6A, the input masking layer 74 may be located between the light source 76 and the first layer 61. The mask layer 74 may be a prismatic mask array providing a collimating effect for the input light 78 which provides a brighter and more uniform output light 80 around it.

Linear prisms parallel to the y axis can improve uniformity by adjusting the input angle distribution to more closely match the input aperture. Linear prisms parallel to the x-axis can limit the output transverse angle distribution and can also improve the output brightness when used as a fluorescent lamp light source. In other forms of the invention, diffusion of the light source is expected, where the diffuser 79 is used to diffuse a light distribution that diffuses light to improve light uniformity. As the diffuser 79 a lenticular array is preferred, with the cylindrical lenslets parallel to the y axis. Further, diffuser 79 may be a standard surface or volume diffuser, may be a discrete film, or may be collectively coupled to wedge-like layer 61. Multiple prism or diffuser films may be used in combination. This film forms diffuser 79 and the cut layer 74 can be transversely positioned to change its effect.

In another preferred form of the invention, a portion of the total internal use CPC portion 100 (composite parabolic concentric) may be inserted between the light source 76 and the first layer 61 (FIGS. 2L, 12O and 12p). The CPC unit 100 adjusts the input light to more closely approximate the input light to the input aperture ratio. The CPC unit 100 is preferably formed by coalescing with the first layer 61.

Reflecting elements 92 and 94 shown in FIGS. 7 and 8 may be arranged in a form to minimize light through from light source 76 to light-pipe openings, respectively. This is equivalent to minimizing light reflections returned to the light source 76, which partially absorbs the returned light. The light source 76 is typically cylindrical and is surrounded by a transparent glass lid 93, each having a circular cross section as shown in FIGS. 7 and 8. Light sources of this example include fluorescent tubes and incandescents with long filaments. The outer diameter of the light source 76 may be equal to or less than the inner diameter of the glass lid 93. FIG. 7 shows a conventional U-shaped reflector 92 formed by wrapping a mirror reflective polymer film around the light source and bringing it into contact with the wedge-shaped layer 12 at each end of the film. Typically, this reflector element 92 is formed in the form of an arc of a circle on the side of the light source 76 which is roughly opposed to the wedge-shaped layer 12, with the straight portions being approximately each endpoint of the arc and the wedge-shaped layer 12. ). This manner of coupling the reflector element 92 to the wedge-shaped layer 12 may be most easily achieved where there are no sharp corners in the cross section of the reflector element. In general, the light source 76 does not allow contact with either the wedge-like layer 12 or the reflective film to minimize thermal and electrical coupling that may reduce lamp efficiency.

In one embodiment of the present invention shown in FIG. 8, the reflector element 94 can be designed and the light source 76 can be arranged so as to minimize the portion of the light returned to the light source 76 to increase efficiency. In one preferred embodiment, at least one section of reflector element 94 is formed such that at each point a line extending perpendicular to the surface of reflector element 94 abuts the circular cross section of light source 76. The reflector shape accordingly is known as the involute of the light source 76.

Where involutes provide maximum efficiency, other forms may generally be easier to manufacture. Polymeric membranes can easily bend into a gentle curve that includes an almost semicircular arc as described above. In the case where the cross section of the light source 76 and the semi-circular section of the reflector element 92 have the same center as shown in FIG. 7, the semi-circular section of the reflector element 92 returns all incident light to the light source 76. It can be seen that the efficiency is lowered. This inefficiency is a common characteristic of self-absorbing circular light sources and concentric semicircular reflectors. This general characteristic can be derived simply from the principle of ray tracing or asymmetry invariant. Although the reflector element 92 is not perfectly circular, if the cross section of the light source 76 is centered near the center of curvature of the reflector section, each portion of the reflector element 92 returns light to the light source 76. There is a tendency.

In another preferred embodiment, the cross section of the reflector element 94 in FIG. 8 includes one or more nearly circular arcs, the efficiency of which is determined by the light source 76 being away from the center of curvature of the reflector element 94. Increased by centering Ray tracing and experimentation show that these preferred embodiments can be determined using the following rules:

1. The cross section of the reflector element 94 has a maximum at the limit of the x direction length such as the maximum thickness of the wedge layer 12 (or the light pipe);

2. The cross section of the reflector element 94 does not have optically pointed corners;

3. The radius of curvature of the reflector element 94 is made as large as possible; and

4. The light source 76 is placed as far from the wedge layer 12 as possible, but far enough from the reflector element 94 to prevent the worst change in manufacturing.

FIG. 8 shows a light source 76 having an inner diameter of 2 mm, an outer diameter of 3 mm, a thickness of 5 mm of the wedge layer 12 (or a light pipe), and 0.25 at intervals between the outer diameter of the reflector element 94 and the glass lid 93. An example of a coupler that satisfies the design rules described above for manufacturing tolerances that allow mm is shown. In this example of the preferred embodiment, the radius of curvature of the reflector element 94 is 2.5 mm and the center of the light source 76 is located about 0.75 mm away from the opening of the wedge layer 12. Couplers constructed according to this design are about 10-15% brighter compared to the concentric coupler shown in FIG.

The above-described involute and U-shaped reflector elements 92 and 94 are designed to output light to the opening of the wedge layer 12 with angles approaching ± 90 ° with respect to the normal of the opening surface. In another preferred embodiment, the reflector element 94 is shaped to output a debt having an angular distribution closer to the N.A. of the device 10. As shown in FIGS. 6B and 6C, the shapes of reflector element 94 include other geometric shapes such as composite parabolic source reflector 86 and non-imaging illumination source reflector 88. One example of a source reflector 88 is described in US patent application Ser. No. 07 / 732,982, assigned to Applicant, which is described herein by reference.

In another embodiment of the present invention shown in FIGS. 6D, 12L, 12N and 12O, the wedge layer 90 may be non-forged by varying the thickness of the wedge-shaped cross section for various selections of wedge-shaped cross sections. -monotonic). By adjusting this cross section, the light distribution outputted is controlled. In addition, the intrinsic light source effect as well as the photoboundary effect can be combined to give an output light distribution with unwanted anomalies.

Thus, for example, we can compensate for these anomalies by providing a wedge-shaped cross section with a non-linear change in the actual size of the wedge layer 90, typically near the thicker end receiving the input light. This control not only has another degree of freedom to control the light distribution but can also virtually provide any design for compensating for any boundary effect or light source. Moreover, the refractive index can be varied within the wedge layer 90 in the manner described above to modify the distribution of light, and can also compensate for light input abnormalities to provide the desired light distribution output.

[Manufacture of lighting device]

In one form of the invention, the selected adhesives and lighting procedure can be used carefully to make the device 10. For example, the wedge layer 12 having a refractive index n ₁ can be bonded to come into close contact to the first layer 28 having a refractive index of n _2. The adhesive layer 60 (see FIG. 3B) is tightly bonded to the bottom surface 16 of the wedge layer 12. In general, the order of joining the various layers can be in any order given.

When applying layer 12 to layer 28 and other such layers, the manufacturing process preferably includes the formation of inner layer contact surfaces that are substantially smooth contact surfaces. Otherwise, since each contact surface between layers having different refractive indices acts as a reflecting surface with its own characteristic critical angle, these inner layers suitably disposed may degrade performance. If the contact surfaces are substantially gentle, the deterioration effect of the nonuniform surfaces is ignored. Therefore, in the stacking of the various layers of the device 10, adhesives and / or bonding techniques that provide the methodically described smooth contact surface layers should be used. Examples of lamination processes include, without limitation, bonding without additional adhesive layers, applying one layer and then bonding to a second layer with an adhesive, and applying the membrane layer to two adhesive layers (one side of each layer side to be joined together). Include.

In a preferred embodiment, the stacking of layers is done without any additional inner layers whose potential contact surface roughness distorts the light distribution. An example of this geometry for device 10 may be a liquid layer between wedge layer 12 and second layer 30. This method works best if the first layer 29 (liquid layer, etc.) serves as an adhesive layer. Whether in part or in whole, the adhesive can be cured at any time before or after the joining of the various layers of the device 10. As such, the optical contact surface is defined by the bottom surface of the wedge layer 12 and the top surface of the second layer 30.

In another embodiment where a coating is used as the adhesive layer, the first layer 28 may be a coating applied to the second layer 30. Next, the coating film may be laminated to the wedge layer 12 in a second step by applying an adhesive between the coating film and the wedge layer 12. Because the second layer 30 is typically supplied in the form of a continuous film roll, it is desirable to apply a low index coating to the second layer 30 rather than directly to the wedge layer 12. Indeed, coating such continuous rolls is more cost effective than coating discrete pieces. In this way, it is more convenient to control the thickness of the applied low index layer.

In another embodiment, the second layer 30 is made by directly attaching the first layer 28 without using additional adhesive. For example, the second layer 30 may be manufactured by applying a layer of polymer material to the first layer 28 and then molding the material to have a predetermined second layer structure. In another example, the first layer 28 can function as a carrier film during the enbossing of the second layer 30. Using an appropriate temperature during the enbossing process, the second layer 30 can be heat-fused to the first layer 28. This heat-fusing can be achieved using a conventional FEP first layer film by enbossing at nearly 500 ° F. or higher.

In another embodiment using a membrane and two adhesives, the first layer 28 is laminated to the wedge layer 12, or using the adhesive between the two types of contact surfaces, the wedge layer 12 and the second layer ( The film laminated between 30) can be extruded or molded. To minimize the harmful light scattering described above, the adhesive layer should be flat and smooth. The film can be obtained as a low index material in an inexpensive form useful in the industry. This additional adhesive layer can increase the strength by means of a multilayer construction with an adhesive between each of the layers.

With the use of a general adhesive, the performance of the device 10 is optimized when the adhesive index between the wedge layer and the first layer is as close as possible to the index of the first layer 28. When the critical angle at the wedge / adhesive contact surface is as low as possible, light undergoes minimal reflection away from the lower quality film contact surface before exiting the device 10. In addition, the index change at the surface of the first layer film which reduces the roughness effect of the film surface is minimized.

The masks can be made by micro-machined the mold using a master tool. Machining can be carried out by controlling with a diamond tool of the appropriate shape. The master tool can be replicated by known techniques such as electric moulds or moulds.

Each replication step reverses the desired surface shape. At this time, the resulting mold or replica can be used to enboss the desired shape in the second layer 30. Directly controlled surfaces can also be used, but the enbossing method described above is preferred. It should be appreciated that the "milling" process may include chemical etching techniques, ion beam etching, and laser beam etching.

In another mechanical manufacturing method, the face 34 (see FIGS. 2B and 2M, for example) is enbossed or moulded using a hard tool having a reversal of the desired face 34 profile on one surface. It can be produced by a welding process such as. Thus, manufacturing problems are reduced by the materials that machine the appropriate tools. Generally, machined tools are used as templates to form the tools that are actually used in the mold or enbossing process. The tools are typically replicated by an electrical mold. Since the electric mold inverts the surface profile and the electric mold can be formed from other electric molds, any number of such inversions are achieved and the directly machined "master" can have the shape of the mask 3A or its inversion. have.

The tool 34 of the face 34 may be manufactured by single-point diamond machining, where the distance between the cuffing tool and the workpiece is varied to track the desired profile. Diamond cuffing tools should be very sharp, but in general, almost any profile can be generated. Certain designs may also require specific adaptations to match the non-zero radius of the cuffing tool. If curved masks are required, arcs are preferred to facilitate manufacturing. The cuffing tool is moved through the cut substrate and cuts the groove having a similar shape of the tool. It is desirable to machine the entire piece using a single diamond tool. When this method is used to create the "focusing" shape of the mask 34, the variable groove profile must be designed so that various groove profiles can be machined by the same tool. The shape change required can still be achieved by varying the angle of the tool as well as the groove space and depth.

Preferably, the design of the burr 34 satisfies some general limitations.

1. A nearly linear change in the center of the illumination angle distribution as a function of position. A change of 11 ° ± 5.5 ° from the top to the bottom of a typical computer screen is effective.

2. The width of the variable angular distribution of the light output should be nearly proportional to the local illumination to achieve an almost uniform brightness for the observer. The examples provided below show that the spatial distribution is nearly uniform, such that the angular cone has a nearly uniform width.

3. The space between the grooves of the bevels 38 should be large or irregular enough to avoid diffraction effects and should be chosen to avoid moir patterns when used in LCD panels. In practice, these requirements define the allowed spatial variation.

In manufacturing the device 10, for example, the viewing angle depends on the tilt and bending of each of the facets 38. Focusing is accomplished by rotating the horsepower structure as a function of position. Using the example of a 150 mm screen viewed 500 mm apart, the illumination cone can be varied by 17 degrees (ie ± 8.5 degrees) from top to bottom. In the case of a typical material acrylic, FEP, this requires that the mask surface rotates by about 5.7 ° from the top to the bottom of the screen 89 (see FIG. 9B).

The constraints of the design can result from the limitations (1)-(3) combined with the need to machine various curved grooves with a single tool. For example, maintaining a constant angular width (constrain # 1) at a constant cut depth requires a compensating change in groove space or groove depth. Specifically, the linear change in groove space can be reduced to a level where the shape tool that cuts the groove so that a portion of each curved reflector face (see FIG. 2M) is covered by the upper edge of the adjacent face is negligible. . This spatial variation can be quite small to satisfy constraint # 3.

Another manufacturing method may include vapor deposition, sputtering or ion beam deposition of the first layer 28 since the first layer may be very thin as described above. Likewise, second layer 30 may be controllably applied to form the surface layer 30 shown in FIG. 2B (such as masking and layer deposition).

[Wedge Light Guide Plate as Simple Collimator Device]

In the most common embodiment, the wedge layer 12 may function in a combined environment as a simple collimating optical device. The substantially transparent wedge layer 12 has an optical index of refraction n ₁ , and the top surface 14 and the bottom surface 16 converge to establish at least one incident angle Ψ (see FIG. 15). The wedge layer 12 also includes a back side 20 connecting the top face 14 and the bottom face 16. Adjacent to the wedge layer 12 is a transparent first layer 28 having a refractive index n ₂ including an air gap. Adjacent to the first layer 28 is a mirror reflective layer, such as the face 34 of the second layer 30.

Substantially non-collimated light is introduced through the back side 20 by the source 22. Light propagates in the wedge layer 12 with each ray decreasing the angle of incidence to the top and bottom surfaces 14 and 16 until the angle of incidence is less than the critical angle θ _c . Once the angle is less than θ _c , the light beam exits into the atmosphere. Light rays exiting through the bottom surface 16 are reflected back to the wedge layer 12 and then output to the atmosphere. By the above-described angle-filtering effect, the output light is collimated within the cone of the angular width represented by the following equation.

Δθ 2Φ ^1/2 (n ² -1) ^1/4

The region 99 to be illuminated is beyond the end of the wedge layer 12 and is located substantially within a large Δθ of substantially the above defined width.

In another preferred embodiment, the light-redirecting means may be disposed beyond the end of the wedge layer 12 and substantially disposed within the cone Δθ of the above defined width. The light-directing means can be a lens, a planar mirror reflector, or a curved reflector. The light redirecting means reflects or refracts the light in the area to be illuminated. Other details and uses for such redirecting means, such as lens diffusers, will be described below.

In the embodiment of FIG. 6 with two air gaps or transparent dielectric layers, the light redirecting layer is independent, thus making it possible to construct a device with other types of layers. For example, it is desirable to use two transmission redirecting layers whenever light is emitted from both sides of the device 10 or whenever maximum collimation is required. In general, examples of all inventive redirecting layers 82 for two redirecting layers include the examples of FIG. 12, where the letters in parentheses correspond to the appropriate figures in FIG. 12. That is, (a) from two refractive mask layers 124, (c) wedge layer 12 with diffraction grating 120 or hologram 122, (b) diffuser 126 in Figure 12B. Two mask layers 128 having surfaces 120 designed to refract and reflect the light output therein, such surfaces 130 can switch the light output through an angle greater than the angle by refraction alone. (d) two refractive single mask layers 132 (prism), (e) top surface redirecting for wedge layer 12 having refractive single mask layer 134 with curved output surface 136 for focusing. Layer. The bottom surface 138 includes a redirecting layer for refracting and reflecting light using the masking layer 140, the masking angle being changed depending on the position to focus the output light 142 at F, ( f) The bottom redirecting layer 144 consisting of the refractive mirror layer 146 and the bottom redirecting layer consisting of the refractive / inner reflecting layer 148 having a narrow angular output of light, and the diffuser layer 150 smoothing the light output angular distribution. Can be added to widen, (g) the top surface redirecting layer of the refractive / internally reflective mirror layer 152 having a refracting surface 154 convexly curved to widen the output angular distribution, so that the mask angle varies with position, The configuration may further include a transverse lens diffuser 156 that selectively directs the output angle cone to produce a desired field of view at a defined distance, which diffuses non-uniformities that are not eliminated by the curved masking layer 152. The floor redirecting layer includes a refracting / inner reflective masking layer 158 that is convexly curved so that the reflective layer 160 broadens the light output angle distribution in a controlled manner, and (h) widens the output angle distribution in a controlled manner and is uniform. A top redirecting layer comprising a refractive mask layer 162 with a curved mask 164, having a narrow angular output of flat masks 168 and varying with position to focus the output light at a defined distance. The refraction / inner reflective masking layer 166, the parallel lens diffuser 170, having a spherical structure, can be used to smoothly widen the output angular distribution and improve uniformity in a controlled manner. Printed or adhered to the gaseous base, the transverse lens diffuser 172 can be used to diffuse non-uniformities that are not removed by the parallel lens diffuser 170. It is. The combination of the focused flat-mask layer 166 and the diffuser 170 allows to create the desired viewing area at a limited distance, similar to the use of a focused curved mask. Also shown is an LCD component 173 (virtual line) and any other form of illumination device 10 usable with it.

In other structures, one transmissive and one reflective redirecting layer may be combined. These are combinations of the various transmissive redirecting layers and the reflective redirecting layer described above. The reflective redirecting layer may be a specular reflection layer, a partial diffuse reflection layer, a diffuse reflection layer, a faceted layer, or a combination thereof. This structure is desirable when lighting is required on only one side or in some cases where minimum cost is important. Examples of such a structure include: (i) a structure in which the bottommost specular reflector 174 is combined with an upper transmission diffraction grating or transmission flowchart 176; (j) a structure in which the bottom surface reflector 178 is combined with the top surface refractive mirror layer 180, the diffuse reflector 182 (shown in phantom in FIG. 12J), and the embedded image forming layer 171; (k) The bottommost specular reflector 184 is coupled with the top refracting / inner reflecting facet (face) layer 186 and the facet (facet) structure varies with position to focus the output light at a finite distance and is depicted in phantom lines. A structure having a diffuse reflector 188; (l) a structure in which the bottom surface reflector 190 is combined with the top surface refractive / inner reflective masking layer 192 and the curved surface 194 is used to gradually magnify each output of light in a controlled manner and to improve uniformity. There is. The thicknesses of the wedge layer 12 and the top and bottom surface low refractive index layers 196 (eg, air gaps) vary to affect the light output spatial distribution; (m) the bottom reflector 198 is partially specular, partially diffuse reflective to improve uniformity; 12M shows an initial reflector where diffuse reflection can be controlled by the addition of an integrated lenticular diffuse reflector 200; The diffuse reflector 200 is designed to selectively reduce unevenness appearing in the output in the overall y-lateral direction near the thick end; A top redirecting layer is also included that is refractive / internally reflective and has a reflective curve; (n) the lower reflective layer 204 is a partial specular reflection, a partial diffuse reflection layer to improve uniformity; 12N shows an initial reflector 206 that is slightly roughened to reduce specular reflection to selectively reduce unevenness in the output near the thick end 208; A refractive / internally reflective upper redirecting layer 210 with a flat mirror layer 212 is used, and the multi-faceted structure (masked structure) changes to redirect light at a common focal point of a finite distance on each side; Transverse lenticular diffuser 213 is shown in phantom; Parallel lenticular diffuser 214 is used to progressively enlarge the output angular distribution in a controlled manner, converting the focal region of flat mirror layer 212 to a wider preferred viewing field; Lenticular diffuse reflector 213 also improves uniformity; LCD display 216 or other transparent image is shown in phantom lines; (o) In a preferred embodiment, the eccentric coupler 218 uses a uniformity enhanced lenticular diffuse reflector 220 shown in phantom in FIG. 120. The converging taper 222 or CPC (integrated with the wedge layer) converts the output angular distribution so that it more closely matches the input N.A. of the wedge layer 12. The thickness of the wedge layer 12 changes gradually to affect the output spatial distribution to improve uniformity; Lower redirecting layer 224 is a specular or partial diffuse reflection reflector; The upper redirecting layer 226 is a refractive / internal reflecting face (face) layer 228 with a convex reflecting surface 230 to gradually enlarge the output angle in a controlled manner; The face (face) structure varies with position to selectively orient each cone of light from each face to form the desired field of view 232 at a finite distance; Lenticular diffuse reflector 234 is shown in phantom; LCD display 236 or other transparent image is also shown in phantom lines; Since the redirecting and low refractive index layers do not need to cover the high converging portions, it is advantageous that the high converging N.A.-matching portions are combined with the mask (facet) redirecting layer; Thus the input opening (and thus efficiency) of the device 10 increases with a minimum increase in the total thickness of the device; (p) Another preferred embodiment for LCD backlighting uses an eccentric coupler with a uniformly enhanced diffuse reflector, shown in phantom in FIG. 12P; Converging half-taper portion 240 or half-CPC (integrated with wedge layer 12) transforms the combiner output angular distribution to more closely match the input N.A. of wedge layer 12. In addition, a diffuse reflector 239 (virtual line) may be interposed between the light source 217 and the wedge layer 12. The fully cut half-CPC 240 is a simple taper. The bottom reflector 242 of partial specular reflection, partial diffuse reflection is used to improve uniformity. FIG. 12P shows an initial reflector 244 that is slightly roughened or shaped into a series of parallel reflective grooves to reduce specular reflection to selectively reduce unevenness appearing in the output near thicker ends; Upper redirecting layer 246 is a refractive / internally-reflected surface (side) layer 248 having a convex surface 250 that is convex to gradually enlarge the output angle in a controlled manner; The multifaceted (facet) structure varies with position to selectively redirect each cone of light from each face to form a desired field of view at a finite distance; Transverse lenticular diffuser 252 is shown in phantom lines. Also included are LCD displays 254 or other transparent images shown in phantom lines.

Since the redirecting high refractive index layer does not need to cover the high converging portion, it is advantageous that the high converging NA-matching portion (such as half-taper portion 240) is combined with the redirection layer so that the light receiving opening of the device 10 is It is increased without increasing the total thickness. The advantage is also given by the full taper 222 shown in FIG. 12O. However, in contrast, the half-taper portion 240 of 12p provides greater thickness reduction on one side instead of longer in the taper direction for the same N.A.-matching effect. Since the topmost low refractive index layer may be thicker to improve uniformity, it may be desirable to focus the thickness reduction on one side as shown. This structure can be made easier because the lower reflective layer can be integrated into the combiner reflector cavity without having to bend the reflective film around the corners; (q) lower specular or diffuse reflection layer 256 may be combined with single-sided refractive top layer 258 in another embodiment (see FIG. 12Q); (r) for internal lighting, double "bat-wing" angle light distribution is preferred; An upper refractive layer 262 with a face 264 is shown in FIG. 12R, which has a curved front to gradually magnify each output and improve uniformity and the output light is mainly directed to the front quadrant; Lower reflective layer 268 reflects light primarily through the backside of the upper redirecting layer and the output is directed substantially toward the rear quadrant.

As is known in the art, the various elements shown in the figures can be used in combination with the elements of the tapered lighting device. Examples of two combination configurations are shown in FIGS. 13 and 14, each drawing also including features unique to the structure shown. As shown in FIG. 13, the two wedges 276 may be combined and integrally formed. This combination can provide higher brightness than a single wedge of the same size because the two light sources can supply light to the same total area. In these devices the brightness increases, but the efficiency is similar because the two light sources require twice the power required for one light source. Redirect film 272 with face 274 may be of a single symmetrical design that receives light from both directions as shown. Alternatively, the redirecting film 272 may have a different design for each shock of the butterfly.

A three-dimensional analysis of tapered disc 270 as shown in FIG. 5 is shown in FIG. 14, cut to show the appearance of the various layers. The redirection layer 280 takes the form of a lens (eg Fresnel lens 280 shown) with the redirection layer 280 directly above the light source 288 overlying the gap in the axis of the light pipe portion 284. . Just below the light source 288 is a reflector 290 disposed to prevent light from leaking and to redirect light into the light pipe portion 284 or through the lens. The reflector is provided with at least one opening to allow passage of the device, such as a wire or light pipe.

[Use of image forming layer or colored layer]

All embodiments of the present invention may include one or more layers having variable transmittance or coloring at least a portion of each output to form an image. The image forming layer may include a still image such as a normal transparent display, or a selection control image such as a liquid crystal display. The image forming or colored layer may be disposed over one of the redirecting layers or may alternatively comprise an intermediate layer between one of the low refractive index layers and the associated redirecting layer, or an internal element of the redirecting layer. For example, the upper image forming layer 129 is shown in phantom in FIGS. 12C and 12G. Examples of the inner image forming layer 171 are shown in Figs. 12H and 12J.

In one preferred embodiment, the image forming layers (such as 129 and 170) are polymer dispersed liquid crystal (PDLC) layers. With proper arrangement of the layers an image or color can be projected from the device into the selection of the output angular distribution. The image or selected color may be substantially absent in the remainder of the output angular distribution.

[Double Reflective Wedges for LCD Panel Lighting]

In some applications, it is desirable to illuminate a single LCD panel selectively by ambient light or active backlighting. In this application the ambient lighting is chosen in a well lit environment to minimize power consumption by the display. Active backlighting is selected when the effective ambient lighting is too low to provide adequate display quality. This optional dual operation mode requires a back lighting device that can efficiently backlight the LCD in the active mode and reflect the ambient light efficiently in the ambient mode.

The most prevalent prior art bi-modal liquid crystal display is a "transflective display 101" as shown in Figure 16B. This approach utilizes a conventional backlight 102 and a transmissive LCD panel 103 and an interlayer 104 that is partially reflective and partially transmissive. To achieve adequate ambient light mode performance, the interlayer typically should have a reflectance of 80-90%. This low transmittance makes the transmissive reflective display 101 inefficient in the active mode of operation.

Another embodiment of the present invention is shown in FIG. This embodiment outperforms prior art transmissive reflective displays in active mode and exhibits significant performance even in ambient light mode. In this embodiment, a wedge layer 12 (refractive index nl) having a bottom surface 16 is bonded to a transparent layer 28, possibly with an air gap, with a refractive index n ₂ <n ₁ . As shown in Fig. 16A, the reflector layer 105 is preferably similar to the reflector used in the conventional LCD panel, for example, used exclusively for the ambient light mode. On the top surface 14 of the wedge layer, a masked redirecting layer 106, such as a lens diffuser 20 having a micro lens, is placed almost parallel to the y axis. The liquid crystal display panel 107 overlies the masked redirecting layer 106. The backside 20 of the wedge layer 106 is coupled to the light source 22.

Because lens redirecting layer 106 and wedge layer 12 are substantially transparent to incident and reflected light, in ambient light mode, device 10 operates in a manner similar to conventional ambient light mode only displays. When the active mode is selected, the light source 22 is activated and the plurality of layers spread light substantially uniformly across the device 10 by the relationship between the refractive index and the convergence angle of the plurality of layers, as described above. This uniform illumination is emitted through the top surface 14 of the wedge layer 12. In the preferred embodiment, the reflector layer 105 is almost mirror like to maximize the performance of the ambient light mode. In a preferred embodiment, the light emitted from the top surface is emitted in large quantities at a grazing angle which is not suitable for transmission by the LCD display panel 107. As noted above, the redirecting layer 106 redirects some of this light by the combination of refraction and total internal reflection. The redirecting layer 106 is preferably designed such that at least 10-20% of the light is redirected at an angle of less than 30 degrees from the LCD normal (typically the highest LCD transmittance within this angle range). Since prior art transmissive displays are considerably inefficient in active mode of operation, it is sufficient to redirect only a portion of the back-illumination at an appropriate angle.

[Processing of Polarized Light]

In another aspect of the invention, the light processed by the optical device 10 has inherent polarization (linear polarization, rotation polarization and elliptic polarization, etc.), which polarization is illumination or polarization from a liquid crystal display ("LCD") system. It can be advantageously used to improve other outputs depending on the use of the light provided. In a system employing an LCD, one type of polarized light 308 needs to be removed and only another type of polarized light transmitted to the LCD layer.

In the example shown in FIG. 30, the conventional polarization layer 312 selectively absorbs one polarization up to an amount corresponding to about half of the light incident from the light source, and the selected polarization passes to the LCD layer 316. Light polarized with appropriate polarization is processed in a desired manner by the liquid crystal and second polarizer 314 to provide the shape of the displayed object. In such a conventional system, about half of the light incident from the light source becomes unnecessary and cannot be used for the purpose of providing the object to the LCD output. As a result, if a means can be found that can utilize both types of polarized light (without removing unnecessary polarization), a substantial gain in efficiency and brightness will be obtained for the liquid crystal display. The present invention is in part directed to this point and the following examples are preferred configurations and methods for achieving this object.

In the most schematic description of the polarization filter, referring to FIG. 30B, the function of the polarization filter layer 307 is to use the incident light 308 composed of two polarization states, type 1 and type 2, to form the polarization state 3 and It is to generate the transmitted light 309 composed of (4) and the reflected light 311 composed of the polarization states 5 and 6. This is associated with reference numerals "first" and "second" below, and states (1), (3) and (5) are called "first polarization 218", and states (2), (4 And (6) are referred to as "second polarization 220". Thus, the forms of states (3) and (5) assume that they have been selected to specify the light that is transmitted and reflected due to the light of the portion incident into the polarization state (1), and states (4) and (6) It is assumed that the polarization state is associated with (2). However, the shape of the polarization state no longer needs to be related in a particular way. For some ranges of incidence angles over some spectral wavelength ranges and some specific selections of input polarization states, the polarization filter layer 307 processes the incident light 308 in accordance with a particular total power relationship and generates output light 309. . If the power Pi is defined in each polarization state i, i = 1,2,3,4,5,6, the condition is as follows.

By definition, the layer exhibiting this property at an appropriate angle and spectral range is in the form of a polarization filter layer 307. In general, the polarization state contemplated may be of any type, such as linear, rotational or elliptical. In the second half, the function of the polarization filter layer 307 will be quantified by the degree of polarization P _T , defined as follows.

From here,

to be. For the lossless layer, the transmittance is associated with the reflectance R by the following equation.

From here,

For the polarization filter layer 307, examples of the layer medium having the above properties are various. Examples include (1) thin film layers prepared by coating, extrusion, or other processes, either birefringent or birefringent, and designed to operate as optical interference coatings, (2) any of the spectral bands of interest "Thick" layers optically thicker than a quarter wavelength in position and acting as Brewster stack even when angle and refractive index do not exactly match Brewster angle conditions, (3) combination of thin and thick film methods, and (4) A layer of at least one type of associative, partially associative or unassociated surface roughness or profile that causes polarization dependent scattering and is produced by methods such as etching, embossing, micro-machining, etc. Examples include, but are not limited to, underlying layers. In general, the aggregation layer formed by one or more types of layers in the above examples is an appropriate polarization filter layer 307 as long as it satisfies the general functional specification described above for the polarization filter layer.

Implementation of the polarization filter layer 307 may be composed of one of a birefringent or non-birefringent layer of a thin film or a thick film. Specific examples and discussion of birefringence layers are provided later.

One embodiment of a thick film-shaped polarizing filter layer 307 is based on the center wavelength 60 of a particular design and the operating angle 3 _inc of a particular design, as shown in FIG. 30C, and based on an isotropic planar layer. do. Layer 313 in this design example includes two types of alternating layers, referred to as high (H) layer 314 and low (L) layer 315, each having optical refractive indices n _H and n _L. . From Snell's law, knowing the angle of incidence, the angle at which light travels in any layer 313 can be found in terms of the refractive index of the layer (n _inc , n _L , n _H ) with respect to the surface normals 3L, 3H. . This is

For P-polarized light 317 incident on the contact surface between two optically isotropic regions, there is a Brewster angle, the angle at which the contact surface reflects zero. These angles (θ _{H / L} , θ _{L / H} ) measured with respect to the surface normal are as follows.

The reflectivity of the contact surface for S polarized light at Brewster's angle can be significant. The layer 313 that transmits the p polarization state differentially can be designed by separating these contact surfaces by an optical thickness of a quarter wavelength. This quarter wavelength thickness t _L , t _H is given by

It can be proved that the H and L refractive indices are related by the design equation.

As an example, consider the following special case:

This means that the design refractive index of the low refractive index layer and the physical thicknesses of the low refractive index layer 314 and the high refractive index layer 315 should be n _L = 1.31, t _L = 145 nm, and t _H = 110 nm, respectively. Can be obtained using sputtered glass and lithium chloride for n _H = 1.5 and n _L = 1.31, respectively. If the design is made consistent with FIG. 30C, the reflectance can be easily calculated by a known Lauard method using the layer 313 surrounded by the refractive index 1.5. Since the outer surface is always an antireflective coating, this consensus assumption is quite common. The reflectances of the various base layers serving as layer 313 are shown in Table 1 below.

Many similar alternative designs exist. More than a single refractive index may be used as part of the thin film structure of layer 313. The surrounding layer need not necessarily be air and the exact number of low and high refractive index layers can also be changed. The carrier or substrate can have different refractive index values. Layer 313 may be changed from quarter wavelength at design angle and wavelength to improve spectral and angular bandwidths. In practice, the feasibility of layer 313 can be a fairly wide band, and Brewster's angle design need not have high precision in refractive index and angle. For example, by changing the refractive index, the s- reflectance and the p-transmittance can be used alternately. The entire system can be flipped without changing functionality.

Modifications of the preferred embodiment include at least two layers of different refractive indices. This arrangement has a relationship where n _H and n _L have a relationship of n _H / n _L > 1.5, minimizing the number of layers required for high polarization selectivity. In addition, optical interference can be improved by using at least one layer having a refractive index n and a thickness t of 50 nm / (n ² -1) ^1/2 <t <350 nm / (n ² -1) ^1/2 . Most preferably used. In the equation given for t _L and t _H in the above description, the wavelength is in the visible light range of 400 nm to 700 nm, the angle of incidence is close to the critical angle, and n sinθ-1 is established, between 1/8 and 1/2 of the light wavelength. This relationship can be derived by noting that the optical interference effect is promoted by a layer having an optical thickness of. Materials and methods for making such layers are known in the art for multilayer dielectric coatings.

The Brewster stack approach differs from the thin film approach described above, except that the layers have a thickness several times the wavelength and tend to function based largely on the incoherent addition of the wave rather than on the interference effect that occurs in the optical interference coating. similar. The design of the polarization filter layer 307 of this type is the same as that of the thin film polarization described above, except that the layer thickness is not important as long as it is optically at least several times the wavelength. The lack of optical thickness suggests that the performance of the Brewster stack implementation should generally be less sensitive to spectral wavelengths and angular changes. The transmittance defined in terms of the transmittances (Ts, Tp) of the s and p polarized light of sets of N-layer pairs in the geometric plane of FIG. 30D can be estimated using the following approximation formula.

The results of applying this formula to the geometry plane with varying number of layer pairs are shown in Table 2.

In general, this type of polarization filter layer 307 requires a much larger refractive index difference and a greater number of layers for the same reflectance. There is no clear boundary between the thin film design and the Brewster stack approach. As thickness increases, the interference effect gradually decreases, and beyond some point depending on the spectral bandwidth of the optical signal, the interference effect becomes smaller than the non-interfering effect. The examples described here are merely interference and non-interfering situations. In extreme cases.

19 illustrates a modification of one form of polarization illuminator system 204. In particular, in FIG. 19B, the system 204 is a wedge-shaped base layer 206 having a cross-sectional area having an optical index of refraction n, and a first surface 208 and a second surface (converging to define at least one inclination angle Φ). 210). The base layer 206 further includes a rear surface 211 that spans the first surface 208 and the second surface 210. Light 212 incident by a source (not shown) through the back surface 211 is reflected from the first and second surfaces and exits through the base layer 216, where the light 212 is the surface 208. And the angle of incidence of the first and second surfaces in the normal direction by the reflections from 210 respectively becomes less than the critical angle 3 _c by the interface characteristics of the first layer means such as the base layer 206 and the layer 214. Until it is relatively reduced. This layer 214 is located beyond the second surface 210 relative to the base layer 206 and includes a layer portion having a refractive index n ₂ less than n ₁ . The first layer 214 has a critical angle 3 _{c that} is an interface characteristic between the base layer 206 and the layer portion having the refractive index n ₂ in the layer 214 with an incident angle of light 212 in the base layer 206. When below, light 212 can be output from base layer 206 and then incident to first layer 214.

This system 204 also includes layer means, such as polarization filter layer 216 (see polarization filter layer 307 in the foregoing description), which preferably polarizes one state compared to the other. In addition to the samples described for the filter layer 307, the polarization filter layer 216, which is a birefringent material as another example, will be described below in the context of a particular embodiment in each subsection. In FIG. 19, incident light 212 includes first polarized light 218 and second polarized light 220. Next, filter layer 216 preferably interacts with light 212 to output light 218 in a first polarization state compared to light 220 in a second polarization state. This filter layer 216 may be positioned past the second surface 210 relative to the base layer 206, and the filter layer 216 may also reflect at least a portion of the light 220. This reflected light 220 is transmitted through both the first layer 214 and the base layer 206 to the medium 207 of refractive index n ₃ , such as air. The other light 218 is output from the base layer 206 of the system 204 with the polarization filter layer 216. In FIG. 19B, light 218 is shown to be output to medium 221 of refractive index n ₄ . In the embodiment of FIG. 19B, the relation between the refractive indices is as follows.

n ₄ ≥ n ₂ and

arcsin (n ₂ / n ₁ ) -2Φ <arcsin (n ₃ / n ₁ ) <arcsin (n ₂ / n ₁ ) + 2Φ (9)

In a preferred embodiment, n ₂ and n ₃ may be atmospheric layers where n is approximately one. The same refractive index equation can be applied to FIG. 19A, where FIG. 19B is a variation thereof and the first layer 214 of refractive index n ₂ is located further from the base layer 206 than the polarization filter layer 216. In the embodiment of FIG. 19B, the first layer 214 is closer to the base layer 206 than to the polarization filter layer 216.

In another embodiment shown in FIG. 19C, the index of refraction is equal to Equation (10) below, resulting in continued internal reflection rather than being emitted through the first surface 208 as shown in FIGS. 19A and 19B. Light 220 of the second polarization state. Thus, the index of refraction n ₃ can be small enough to reduce the angle outside the desired reflectivity range of the light 220 represented by the light 220 d1 filter layer 216. As a result, at least a portion of the light 220 passes through the second surface 210 but is separated at an output relative to the light 218 in the first polarization state. In the example of FIG. 19C, the refractive index has the following relationship.

n ₄ ≥n ₂ and arcsh (n ₃ / n ₂ ) <arcsin (n ₂ / n ₁ ) -4Φ (10)

Very preferably the polarization filter layer 216 outputs light 218 and reflects light 220 when the incident angle is large in the equation.

θ _p = arcsin [1-4Φ ((n ₁ / n ₂ ) ² -1) ^1/2 ] (11)

When the angle of the incident light is less than 3p, the filter layer 216 actually transmits the light in both polarization states (ie, the light 218 and the light 220).

In another embodiment of the present invention, for example shown in FIGS. 20A-20C, the system 204 is a light redirecting means, such as the light reflecting layer 222 shown in FIG. 20A, and more generally shown in FIGS. 20B and 20C. Light redirecting layer 224 as shown. In general, in the apparatus 10 (system 204 of FIG. 20) of the present invention, light redirecting means may be defined with the concept that incident light propagates and deviates from the light redirecting layer 224. Consider the case where light rays propagate parallel to the unit vector r _c in an optical medium having a refractive index n _i . If u is a unit vector orthogonal to the light redirecting layer 224 at the point of incidence of the light rays and orients from the light redirecting layer 224 toward the beginning of the incident light, then the incident light rays interact with the light redirecting layer 224. To deviate from the interaction zone. If the stray light propagates parallel to the distribution of the unit vector r _c in the optical medium having the refractive index n _i , the light redirecting means comprises a layer which processes the incident light, which stray light incident through the operating angle range. It has one of the following characteristics considered.

(1) n _c (r _c xu) is not equal to n _i (r _i xu) for at least 25% of the deviation

(2) r _c = r _i -2 (ur _i ) u (13) for at least 90% of the deviation

The light redirecting layer 224 interacts with (a) the light surface where the light is coarse, (b) the light interacts with the light surface that is different from the incident surface, or (c) the redirecting layer 224 is at an appropriate angle. If the light is diffracted, the light direction is redirected according to the condition of Equation (12). For example, the light redirecting means according to condition (1) may be in a state combined with transmission or reflection, diffraction or non-diffraction, and a prism or texture layer. In addition, the light redirecting layer may be a diffraction grating, a hologram, or a binary optics layer.

The light redirecting means redirects the light according to condition (2) in which Equation 13 is a specular reflector. Examples of such light reflector may be a metal coating (eg, the light reflector layer 222 of FIG. 20A may be metal coated), a multilayer dielectric coating, or a combination thereof. In each case, the inner and outer surfaces are preferably smooth and parallel to each other.

20A, one of the preferred embodiments, includes light reflection and reflecting means in the form of a reflector layer 222 that reflects light 220. The reflector layer 222 is a flat light reflector positioned above or below the first side 208 of the base layer 206 and preferably metal coated. Also shown is an interfering layer of refractive index n ₃ located between the base layer 206 and the reflector layer 222. The interference layer 223 may be part of the base layer 206 or a separation layer due to functional interaction between the base layer 206 and the interference layer 223. The refractive index n ₃ of this interference layer 223 can be adjusted to face the interference layer 223 and then affect the resulting light 212 spatial and angular distribution.

As can be seen in FIGS. 20B and 20C, the light redirecting layer 224 may be located at different locations, each layer 224 having a different characteristic and achieving different light output characteristics as required for a particular application. You can do it. Also examples of light redirecting means as well as in specific embodiments are shown in the remaining figures and will be described in detail below.

In another embodiment of polarization illuminator system 204, light conversion means are included and are shown, for example, as polarization conversion layer 226 in FIGS. 21 and 22. In this preferred embodiment, the refraction is n ₄ ≧ n ₂ and must satisfy the condition of equation (9). In these embodiments, the light converting means differs from at least one polarization state (such as light 220) (such as light 218, light 227 in a third polarization state, which is a combination of the first and second states). And a layer for changing to a polarization state.

The polarization converting layer 226 has a function of changing the polarization state to another state by rotating polarization by 90 ° (π / 2). This conversion is also most preferred in the case of inclined incidence. As an example, when the refractive index perpendicular to the optical axis is not related to the direction, this conversion characteristic for uniaxial birefringent materials will be described. Most preferred materials are elongated fluorescent polymer films of this kind and the like. If the text rate differs in all directions, the more general birefringent material can use the following general methods described here. To understand the polarization conversion process, one considers normal incidence.

As shown in FIG. 30E, the plate 229 of birefringent material has a horizontal axis along the vector K and the optical axis is along the vector I (see FIG. 30F). For elongated birefringent membranes, the stretching direction will be along the vector I. The vectors I, J, and K are orthogonal trivalent unit vectors along the x,, and z axes. At normal incidence, the normal waveform is along the vector K. The polarization of the electromagnetic wave can be explained by the displacement vector K. FIG. D 'is called polarization for ordinary light rays, D "is called polarization for abnormal light rays. N' is called normal refractive index, and n" is called ideal refractive index. The optical axis of the birefringent plate 229 may be oriented at an angle of 45 [deg.] ([Pi] / 4) with respect to the incident polarization vector. This vector has two components, D ₀ x = (1/2) D _o coswt and D ₀ y = (1/2) D ₀ coswt. In the birefringent plate 229, the vector D has D ₀ x = (1/2) D ₀ cos (wt-δ ") and D ₀ y = (1/2) D _o cos (wt-δ '), Where δ '= (2 / λ) n'h and δ "= (2 / λ) n" h, where h is the plate thickness. Thus, the generated phase difference is δ'-δ "= | (2 / λ) (n'-n ") | h. In particular, if the appearing light has a polarization vector D at an angle to the initial polarization vector D ', δ'-δ" = (or more generally δ'-δ " = (2m + 1), where m is a predetermined integer, which thickness h should be selected as h = | (2m + 1) / (n "-n ') | λ / 2.

In summary, the thickness h is selected by the above equation and is 45 ° to the incident polarization. In a preferred form of the invention as shown in FIG. 26B, the light crosses the conversion layer 226 and the birefringent plate 229 twice so that the actual thickness is half that specified above. That is, the thickness is a known λ / 4 plate. If there is reflection from the metal mirror 231, both components are further subjected to a phase shift so that the result is unchanged.

In the embodiment, once light is incident at an angle with the conversion layer 226 (see FIG. 26B), it is necessary to split the incident beam into two beams (known birefringent effect), which does not cause difficulties. The reason is that the two beams appear to be parallel to the initial direction, but this is not a problem because each is slightly displaced. The two beams are in close contact with each other and the displacement is less than λ. Angular division is △ θ tan θ _c Δ n / n where θ _c is the critical angle and Δn− (n ″ −n ′), n = (n ″ + n ′) / 2. The displacement is hΔθ _c / cos θ _c = hΔntanθ / cosθ _c . However, by selecting hΔθ _c / cos θ _c = λ / 4, the displacement is automatically less than λ and two light beams can be treated as one.

The geometry of the inclined angle of incidence above the short side shape of the birefringent plate 229 is rather complicated to simplify the materials and introduces an Euler angle as shown in FIG. 30F. The relationship between the (i, j, k) vector three phases and the (I, J, K) vector three phases can be seen from Table 3.

TABLE 1

The normal to the air / plate contact surface is K, the incident wavelength in the normal direction is k, and the optical axis of the plate 229 is I. Rotate the incident polarization DO by 90 _° . Since incident polarization D ₀ is a contact surface, Ψ ₀ = / 2 is obtained because D ₀ coincides with i ₀ . The polarization D 'of normal light is orthogonal to I and K. Therefore, D 'is set along i'. i'x = O. From Table 3, tan Ψ '= cos _Ψ cosθ. The polarization of the extraordinary light beam D "is orthogonal to both D 'and k. Thus, Ψ" = Ψ' ± / 2. Here, if Ψ "= Ψ '/ 2 is selected, tanΨ" = cos _Ψ / cosθ. In order to obtain the desired output, set Ψ to be 45 ° in the D 'and D "directions. Thus, Ψ" = / 2 and tanΨ = cosθ. In a typical case, θ is θ _c Close to 40˚, Ψ = 37˚. In practice, the most complete polarization conversion can be obtained by experimentally adjusting Ψ using the above equations as starting point and guide as incidence angle and wavelength range. Next, the thickness h of the birefringent plate 229 is determined. As in the case of normal incidence, the condition is h = | (2m + 1) (n "-n ') | λ / 2. However, the ideal refractive index n" is dependent on the incident angle θ and the elliptic refractive index is (1 / n ") ² = (1 / n _o ) ² sin ² θ + (1 / n _e ) ² cos ² θ where n ₀ is the normal refractive index and n _e is the ideal refractive index. n _0. Typically, the refractive index difference is less than 0.1 and approximately (n "-n ') (n _e -n _c ) cos ² θ. Further, the optical path length of the inclined angle of incidence is larger than that of the normal incidence angle. The optical path length h at the inclined angle of incidence is greater than the thickness of the plate 229 by the 1 / cosθ factor. Therefore, since the effective refractive index difference is reduced by cos ² θ, the path length is increased by 1 / cos θ so that the thickness required for the inclined incidence is approximately 1 / cos θ larger than that in the normal direction. In practice, using the above equation as a starting point and guide, h is adjusted as the angle of incidence and the wavelength range to obtain the most complete polarization conversion.

In another embodiment, converting one polarization to another polarization state is considered to comprise three steps: (1) separating the differential polarization state into substantially distinct beams at each origin of system 204 and , (2) polarization conversion is performed without affecting the desired polarization, and (3) light output causes light diffusion with an appropriate angle distribution while the polarization characteristic is lost.

As described herein, various methods are used to separate the polarization states differently in the system 204. For example, the low refractive index layer 214 may be birefringent as shown in FIGS. 31A-31C. Layer 214 may be, for example, an oriented fluorescent polymer conversion layer such that two light beams 218 and 220 appearing at every point of system 204 are orthogonally polarized. This can be used if both conditions are met. The first condition should be large enough that the birefringence of layer 214 is sufficient to prevent overlap between the two polarizing beams 218 and 220. These conditions are summarized by equations (15) to (17), where C is at least 1 and preferably greater than 4, and the second condition is that the direction of birefringent orientation (extension direction) of the first layer 214 is almost parallel to the y-axis

Ψ = 1 -1.5 °, the birefringence must be at least 0.03 to 0.05 to satisfy Equation (15-17). In order to measure the birefringence of various fluorescent polymer films, the following data (average refractive index, birefringence) is calculated.

Tefze 1 250 zh: (1.3961, 0.054)

Tefzel 150 zm: (1.3979, 0.046)

Teflon PFA 200 pm: (1.347, .030)

Even if the Fresnel reflectors did not overlap, the wedge layer 206 laminated with 250 zh material generated polarized beams that were separated.

In another embodiment, greater angular separation in polarization can be achieved by using a faceted redirecting layer comprising a high birefringent material.

A third method for separating the polarization states uses a sheet of polymerized beam splitter consisting of an alternating structure of birefringence / transparent layer 427 shown in Figs. 30G and h. This array of layers 427 may be on top of the collimated backlight 428 and polarized by selective total internal reflection. The refractive index of the film of the polymerized layer 429 parallel to the light incident surface is lower than that of the transparent layer 430, and the refractive index perpendicular to the light incident surface is closely matched with respect to the transparent layer 430, so that the backlight 428 [beam The collimated light beam 431 coming from the slanted to the splitter layer 427 is separated: The parallel polarization beam 431 is internally reflected internally, but the vertical component is transmitted.

One example of such an arrangement is the Mylar / Lexan layer. Mylar refractive indices are (1.62752, 1.6398, 1.486). Lexan refractive index is 1.586. Since the complement angle of the critical angle is 20 degrees, the beam splitter layer 427 will act if the angle of incidence angle is less than 20 degrees (in Lexan). However, if the angle deviates, Fresnel reflections reduce the degree of polarization. For example, at 13 degrees, the Fresnel reflection vertical component is 9%.

Another example of this arrangement of layer 427 is a uniaxial nylon / Lexan. Nylon refractive indices are (1.568, 1.529, 1.498). Here, there are two critical angles, the complementary angles of which are 9 degrees and 19 degrees respectively in the vertical and parallel directions. Therefore, the angle of inclination must be within this angle range so that polarization occurs. Taking the same case as the mylar (30 degree angle) for Fresnel reflection, the Fresnel reflection vertical component is only 5% because the refractive index matching is better.

For each of these examples, each beam splitter layer 427 must have an appropriate aspect ratio so that all beams of the beam 431 have exactly one interaction with the film / lexan interface.

In one embodiment, once light in different polarization states is separated into two orthogonal polarization beams at all locations along the backlight 458, means for converting the unwanted polarization into the desired polarization, for example a flat conversion layer [FIG. 31C]. 346 and FIG. 30G 429].

One method of performing polarization conversion is realized by alternating waveplates combined with one lens or lenticular array. In a first method using a single lens, the light beams 218, 220 arrive on the lenses focused on two non-overlapping strips of orthogonal polarized light at the focal plane. The alternating waveplate acts to rotate the polarization of only one of the beams 220 by 90 degrees, with the light appearing to be completely converted to light 218. This may be realized by the presence of a half-wave retarder arranged to capture only light 220 of one polarization. This can be visually confirmed by large lenses, plastic retardation plates and polaroid filters (Polaroid is a registered trademark of Polaroid).

In the second method using the lenticular array, thin sheet-like lenses and alternating waveplate structures (having the same frequency as the lens frequency) are used, with a delay varying by 180 degrees for each lens. For 1mm thick lenticular arrays, each image is about 1 / 5,000th the size, so registration of a lenticular array with waveplates results in stack-up errors of less than 1 / 100th of an inch. It must be accurate enough to prevent it.

Another method of performing polarization conversion is to use a double Fresnel rhombus (DFR), which is another embodiment of a conversion layer, such as layer 346 of FIG. 31C and layer 429 of FIG. 30G. DFR avoids registration problems by selectively delaying by angle instead of location. This DFR causes the light in the first polarization state to receive a total internal reflection result corresponding to 4 × 45 ° = 180 ° of phase shift, while the light in the remaining polarization states only transmits, so that the output light is one at the end. To be fully polarized with the light of the first polarization of the face. The DFR can be constructed, for example, by having four acrylic or lexan films all embossed with 45 degree prisms, all stacked. For the DFR causing the delay, two orthogonal plane polarization beams L and R are generated (by quarter wave plate). If L is transmitted by DFR, the R beam will be converted to L beam by DFR. Finally, the L beam will be converted to the polarized plane by another quarter waveplate that determines the final plane of polarization.

In the preferred embodiment shown in FIG. 21A, the conversion layer 226 is disposed on the opposite side of the base layer 206 relative to the polarization filter layer 216. In the embodiment of FIG. 21B, the conversion layer 226 is disposed on the same side as the polarization filter layer 216. As can be seen with reference to FIGS. 21A and 21B, the conversion layer 226 may convert light 218 and 220 into light 227 in another third polarization state. This light 227 may be, for example, light of a third polarization state or light of a modification or combination of the aforementioned first or second polarization states. The final polarization depends on the response characteristic of the conversion layer 226. Accordingly, the conversion layer 226 may be designed to respond when it is necessary to generate light in a desired output polarization state, and properly position the layer 226 to generate output light in a desired direction having a desired polarization characteristic. You can.

In another form of the invention illustrated in FIGS. 22A-B, the conversion layer 226 is used for other optical purposes. 22, 23, 24e-f, 25-27, 28a and 28c, and 29 all use the conversion layer 226 to convert light 220 in the second polarization state to light 218 in the first polarization state. To illustrate. In addition, elements of the illumination system 204 are arranged such that light to be processed passes through or at least encounters one or more polarization filter layers 216 after passing through the conversion layer 226 at least once. For example, when processing light 220, the placement of these elements may be returned to pass through polarization filter layer 216 after light 220 passes through conversion layer 226. In some cases, the light 220 may encounter the polarization filter layer 216 two or more times before being output as the light 218 in the first polarization state. 22A-E illustrate examples of various configurations for obtaining the desired output. In FIG. 22A, after the light 212 encounters the polarization filter layer 216, the reflected light 220 passes through the conversion layer 226 and is converted into the light 218. This light is then returned to the polarization filter layer 216 via internal reflection. In addition, in FIG. 22B, light 220 passes through conversion layer 226, is converted to light 218, and then returned back to filter layer 216 after being internally reflected. In these cases, n ₃ is sufficiently low to satisfy the relationship between n ₁ , n ₂ , n ₃ in equation (10).

In the embodiment of FIGS. 22C-E, redirection means in the form of a light reflective layer 222 is added to return the light 220 to the polarization filter layer 216. As described above with respect to the embodiment of FIG. 20A, intervening layer 223 has a refractive index n ₃ that can be adjusted to affect the spatial and angular distribution of light encountered with layer 224. In the preferred form of the invention shown in Figs. 22C-22E, the layers of refractive index n ₂ , n ₃ may comprise an air gap, and in the most preferred form of the invention, the layer of refractive index n ₂ is an air gap.

24A-24F illustrate a sequence of configurations starting with one of the polarization filter layers 216 of FIG. 24A and leading to more complex configurations of the illumination system 204.

In FIGS. 24C-24F, light matching means such as one or more light redirecting layers 224, at least one liquid crystal display (LCD) layer 230, and matching layer 232 are added. The matching means act to convert the light output by the assembly of the other layers into a particular polarization state suitable for the additional layer, such as the target device or the LCD layer 230. As such, the matching layer 232 is a special case of the conversion layer 226.

23A-23C illustrate another form of polarized light illumination system 204 in combination with LCD layer 230. In one general form of the embodiment of FIG. 23A, layer 234 is included. In another particular form of the invention, for example, in FIG. 23, the preferred value of n ₂ is about 1 (see, eg, FIGS. 23B and 23C). In certain aspects of FIG. 23A, n ₂ > 1 may be used. As another way, the preferred choice regarding the relationship between the refractive indices is set in equations (9) and (10).

Examples of yet another preferred embodiment are shown in FIGS. 26A and 26B, which includes a cold cathode fluorescent tube (CCFT) light source 236. This embodiment also includes an angle conversion layer 238 that operates to change the angle distribution of the light. Such an angle conversion layer 238 can control the spatial uniformity of the light output from the device 10 by changing the distribution in the xz plane, for example. In a preferred embodiment, the distribution of output light 250 is nearly uniform in terms of spatial distribution at least 90% of the output surface. The angle distribution of the light 212 on the xz plane is approximately ± θ _max with respect to the normal of the back surface 211.

The back surface 211 is approximately perpendicular to at least one of the first surface 208 and the second surface 210. The angle converting layer 238 may be a tapered light pipe portion, a compound parabolic concentrator (CPC), a micro prism film (FIG. 28C), a rough surface layer, or a flow chart. The angle converting layer 238 is most preferably optically coupled to the base layer 206 without the need for intervening air gaps. The angle converting layer 238 can operate to vary the light distribution on the yz plane, preferably narrower, to improve brightness, LCD image quality, viewer privacy, and the like. In addition, in FIG. 26A, an output diffusion layer 248 may be added before the LCD layer 230 to improve the uniformity of the output light 242 provided to the LCD layer 230 and to widen the angle distribution.

In another preferred embodiment of FIG. 26B, the CPC 239 is coupled to a light source 244 that operates to maintain the output light 250 within the proper angular distribution of the xz plane. In addition, a flat prism facet such as facet 247 may be used to control the range of angles outputted by using light turning means such as a prism turning layer such as layer 246. For example, this type of layer and prism facet is shown in FIGS. 28C, d, e and 29A, b, which will be described in detail next. An embodiment as shown in FIG. 28E relates to a prism layer 251 and a facet 253, which add a light diffusing layer 304 after the LCD layer 302 to provide light distribution on a particular surface. Widen. For example, in the most preferred form of this embodiment shown in FIG. 28E, light 242 passes through the LCD layer 302 within a narrow angle range in the xz plane. Thus, elements of the illumination system 204 are configured to assist in the transmission of light 242 through the LCD layer 302 at an angle at which image forming characteristics are optimized. Using the diffusion layer 304 positioned on the other side of the LCD layer 302 relative to the base layer 206, the diffusion layer 304 is used to produce the viewer output light 250 without diffusing the light 250 on the xy plane. The angle distribution can be widened. For example, diffusion layer 304 may be a "parallel" diffuser, which may take the form of a holographic diffuser or a lenticular diffuser having grooves substantially parallel to the y axis. Viewers at a wide range of angles can view images with optimal angular properties for light 242 subsequently transmitted through LCD layer 302 to form light 25. Exemplary configurations using this type of general configuration are shown in FIGS. 28D, e and 29A, B. FIG. 28D, e, and 29A also show that the output light 242 provided to the LCD layer 302 is diffused only on the xy surface to improve uniformity without widening the distribution of the light 242 on the xz surface. It also includes an epitaxial diffuser layer 252. For example, the cross diffuser 252 may be a holographic diffuser or a lenticular diffuser having grooves substantially parallel to the z axis. Next, this will be described in more detail.

27a and 27b are other preferred embodiments in which the first layer means of refractive index n ₂ is most preferably not air. This embodiment shows another example of the light redirecting layer 224. Moreover, in FIG. 27A, the medium 254 having the coefficient n ₃ need not be air, but the various coefficients of the system 204 must meet the requirements of equation (10) to obtain the overall internal reflection described above. In FIG. 27B, the medium 254 is air, the light redirecting layer 224 has a small curved surface 256, and the light 245 focuses within the preferred viewing area 258.

28 and 29 preferably use an air gap layer as the first layer means, layer 260, where the light 21 has a critical angle of 3 sigma of the contact surface between the base layer 206 and the air gap layer 260. After achieving a smaller angle of incidence, light enters layer 260. The embodiment of FIG. 28B includes a first redirecting layer 262 between the base layer 206 and the diffusion layer 264, and a second redirecting layer 265 on the other side of the base layer 206. The first redirecting layer 262 includes a refractive / internal reflecting prism, and the second redirecting layer 265 includes a refractive prism 268. Two of the polarizing filter layers 216 are disposed on either side of the base layer 260 and transmit appropriate light 218 or 220 respectively passing through each of the associated light redirecting layers 262 and 265.

28C illustrates a more preferred embodiment in which the light redirecting layer 246 includes a refractive / inner reflective layer having a relatively small prism. The surface angle of each of the prisms 247 may vary in accordance with the above-described size of the redirecting layer 246 in the manner described above. This change in angle allows other cones of light entering the prism 247 to focus on the desired viewing area 258 (see FIG. 27B). The light reflection layer 222 may be a metal coating as described above.

The reflector layer 222 may be applied to the conversion layer 226 by conventional vacuum evaporation techniques or other suitable method. Other layers, such as the redirecting layer 246, can be formed by casting the transparent polymer material directly into the matching layer 232 (FIGS. 24C-F and 28C and d). Polarizing filter layer 216 may be manufactured by conventional methods such as depositing multiple thin layers directly on base layer 211. Also included is each conversion layer 274 that is coupled to the back surface 211 (see FIG. 28C). This angle converter 274 widens the angle distribution of the input light 212 with respect to the base layer 206 to help provide the LCD layer 230 with a more spatially uniform shape of the input light 218. 276). Other states of each conversion layer 274 may be a hologram (not shown) and a coarse surface layer coupled to the backside 211 (or other input surface) without intervening air gaps.

In the preferred embodiment of FIG. 28D, the first prism light redirecting layer 249 is disposed between the base layer 206 and the polarization filter layer 216. This redirecting layer 249 reduces the angle of incidence of light 280 incident on the polarization filter layer 216. The second prism light redirecting layer 282 redirects the light 284 output from the filter layer 216 to the LCD layer 302 to the post diffusion layer 216 which is operated with a parallel diffuser as described above. This embodiment includes a CCFT light source 236 with a reflector 290 having a position subsequent to at least a portion of the involute inner diameter of the light source 236 inner diameter. The other part of the reflector 290 that directly faces the back surface 211 is bent or curved convexly.

In the preferred embodiment of FIG. 28E, the light redirecting layer 251 includes a refractive micro prism 253. The polarization filter layer 296 is disposed adjacent to the conversion layer 298, and the despreading layer 252 is disposed between the redirecting layer 251 and the LCD layer 302. Parallel diffuser 304 allows light to pass through LCD layer 302 at a preferred angle to optimize output light 301 for the best image-forming characteristics (contrast, color, fidelity and response time) of LCD layer 302. Disposed on the light outer side of LCD layer 302 having 242.

The embodiments of FIGS. 29A and 29B illustrate some form of advantages of the invention over the conventional LCD polarizer system 304 shown in FIG. 30A. In FIG. 30A, the conventional back art 306 emits light 308 of polarization with almost the same characteristics. A typical conventional LCD layer arrangement includes a first type of polarizing filter 312 and a second type of polarizing filter 314, with a liquid crystal layer 316 sandwiched therebetween. In such an LCD layer arrangement, the first polarization filter 312 is a second polarization state that does not want to enter the liquid crystal layer 316 in order relative to the LCD layer arrangement 310 to provide a high polarization rate, i.e., an appropriate LCD contrast. Must have a very low transmission of light. In practice, the polarization filter 312 also has a high optical density for a given light in the first p-polarized state. Thus, the resulting loss further exacerbates LCD light transmission and image output. In contrast to this conventional arrangement 310, the present invention provides a very high percentage of the light desired by the LCD layer arrangement 316, enabling the use of the actual partial light of the undesired second polarization and the first polarization. It is also possible to minimize the loss of certain light in the state.

In the embodiment of FIG. 28A, this benefit of processing light 218 and 220 for the LCD layer 316 is achieved by placing the conversion layer 226 adjacent to the base layer 206. The polarization filter layer 216 is disposed adjacent to the conversion layer 226. The light redirecting layer 224 includes a curved micro-prism small plane 318 to widen the angle of the light distribution in the xy plane and to improve the uniformity of the light distribution output from the illumination system 204. Reverse diffuser 320 may be preferably illuminated on light redirecting layer 224 or formed on opposite sides of a single polymer layer (not shown). The polarization filter layer 216 is deposited or deposited directly on the conversion layer 226 which is deposited or deposited directly on the first surface 208 in order.

In the preferred embodiment of FIG. 29A, the treatment of the light 218 and 220 for the LCD layer 302 is advantageously accomplished by the use of the first polarization filter layer 324 and the second polarization filter layer 322. However, the first filter 3240 has a relatively low polarization rate compared to the conventional polarizing filter 312. For example, the polarizing filter layer 324 may have a smaller dye concentration than the conventional filter 312. The difference allows for higher LCD light transmission and allows for the above-described image forming characteristics to be improved This preferred embodiment is an LCD system 330 (combination of layer 324, liquid crystal layer 302 and layer 322). And post diffusion layer 328. Preferably, post diffusion layer 328 is laminated to be integrally formed with second polarization filter layer 322.

In the preferred embodiment of FIG. 29B, the advantage of using only one polarization filter layer 248 that results in a reduced cost and increased light transmission of the illumination system 204 is achieved. In this embodiment, the light passing through the matching layer 232 is preferably at least 90% of the light 218 in the preferred LCD polarization state. Coupling angle transformer 334 in combination with backside 211 reduces the angular width of the light distribution in the YZ plane, which further improves the characteristics of the output light forming the LCD image from dimming system 204. .

[Birefringence Layer of Lighting System]

Birefringent materials can be used to benefit the polarization dimming system described above. In the embodiment shown in FIG. 31A, the first layer 214 has two different optical coefficients n _2q and n _2p less than 1 for light 212 in two different polarization states “a” and “b”. It may be a birefringent material having a coefficient n ₂ having a. This light 212 encounters the layer 214 near each critical angle for these two polarization states.

θ _cα = arcsin (n _2α / n ₁ ) (15)

θ _cβ = arcsin (n _2β / n _l ) (16)

The condition of Equation 10 must be independently satisfied for n ₂ , such as both n _2α and n _2β . Light 212 in the polarized state reduces the angle of incidence by 2Φ for each cyclic reflection from the first surface 208 and the second surface 210 as described above. In this example, n _2α > n _2β , and θ _cα > θ _cβ .

When the amount of the incident angle decreases with respect to the polarization state, both the light 212 of the polarization state is the contact surface between the first critical angle θ smaller the birefringence to light having an incident angle of 2 greater than the critical angle θ _cβ than _cα first layer 214 You can meet with Thus, light 218 in the first polarization state is at least partially transmitted through birefringent first layer 214, while light 220 in the second state is preferentially reflected by longitudinal internal reflection. The reflected second state light 220 and the remaining first state light 218 are continuous to reduce their angle of incidence with frozen reflection. Light 218 in the first polarization state is transmitted at each successive point of contact with the contact surface between the first layer 214 and the second layer 206. The light 220 in the second state is at this contact surface until its angle of _{incidence is} less than the second critical angle θ _cβ at the point at which the second state light 220 is at least partially transmitted through the birefringent first layer 214. Continue to experience total internal reflection. _{Due to} the superiority of the mechanism and coefficients n _2α and n _{2β differences} , the light passing through the birefringent first layer 214 has different angular distributions for the two polarization states “a” and “b”.

The birefringent material may generally comprise a crystalline material having an anisotropic refractive index. Preferred materials are stretched polymer films such as stretched fluorine-added films. Thretching orients the film and produces different refractive indices along that direction. The birefringence values of these stretched fluoropolymer films are given as Δn in the range of 0.030-0.054. Other membranes are PVA (polyvinyl alcohol), polypropylene, polyolefin or polyester (Mylar). Mylar is actually biaxia1, but can also be used to rotate polarization. Common uniaxial birefringent materials are: calcite and quartz. These are not practical as stretching films. For example, the two polarization states are well separated only if the two coefficients are sufficiently different. This condition can be expressed by the following equation (17):

θ _cα ≥ θ _cβ sΦ (17)

Here, s must be at least 1 and preferably greater than 4. This condition uses, for example, the resonance value of uniaxially oriented fluorine copolymer as birefringence layer, acrylic copolymer as base layer 206 and Φ (between 1 and 1½ is revolutionary as notebook computer LCD backlighting). Can be achieved.

FIG. 31B is the same as FIG. 31A, but with the redirecting layer 224 added, the preferred embodiment uses air for layer 207 having a coefficient n ₃ . Light 218 and light 220 are output from the system 204 at different angles.

31C shows another variation of FIGS. 31 and 31B, the redirecting layer 224 includes a reflective layer 340 with a flat cut face. Light 218 and light 220 are directed to a conversion layer 346 that transmits light 218 without substantially changing the polarization thereof, while the polarization layer 346 is light 220 in the desired first polarization state. Convert to light 218. The conversion layer 346 shown in FIG. 31C has a configuration that operates to convert polarization only within the angular range occupied by the light 220. Accordingly, the conversion layer 346 uses the angular separation of the light 218 and light 220 to convert the light 218 into the light 220 without converting the light 218 into the light 220. Perform the conversion to).

In the embodiment of FIGS. 31D and 31E, the reflective form of light 220 is returned to the contact surface of the birefringent first layer 214 and the base layer 206. This is achieved by the superiority of the total internal reflection of the light 220 with at least twice passing through the conversion layer 346 which at least partially converts the light 220 into the light 218 in the first polarization state. Since the light 218 has an incident angle smaller than the first critical angle θ _cα , the light 218 is transmitted through the contact surface between the base layer 206 and the first layer 214. This light 218 can be reflected or transmitted by the redirecting layer 224, depending on the nature of the redirecting layer 224.

Repeatedly transmitted and reflected light is shown virtually in FIGS. 31A and 31E. In addition, in the embodiment of FIG. 31D, the conversion layer 346 is on the same side of the base layer 206 as the birefringent first layer 214. The conversion layer 346 is also disposed between the base layer 206 and the birefringent first layer 214. The embodiment of FIG. 31E shows an example having a birefringent first layer and a conversion layer 346 disposed on opposite sides of the base layer 206 as another variation of FIG. 31D.

In the embodiment of FIG. 31F, the system 204 is similar to the embodiment of FIG. 31D, but the redirecting layer 224 includes a layer 311 of small sides. In the embodiment of FIG. 31G, the system 204 further includes an LCD layer 302, a matching layer 232, where the diffusion layer 304 is at a spatial location after light passes through the LCD layer 302. Is placed. The redirecting layer 224 includes a layer 251 of microprisms with flat sides, and a metal coating 342 with high reflectance for light. Also shown is an angle conversion layer 238 for controlling the spatial dispersion of light output from the system 204. The embodiment of FIG. 31H is similar to the embodiment of FIG. 31G, but the plane angle adjusted by the system 204 to other spatial positions for the redirecting layer 224 to focus the light 250 output to the desired viewing area. Use curved surfaces with Angle converter 238 is illustrated as a CPC.

[Light diffuser after LCD layer processing]

In the embodiments of FIGS. 12N and 12O, the LCD display 216 or 236 outputs light to the viewer. In further advanced examples of these embodiments, a post diffusion layer 350 is disposed in the path of the light 250 output from the LCD layer 302 (see FIGS. 32A and 32B). In the preferred embodiments shown in these figures, the approximate operation is similar to the embodiments shown in FIGS. 26B, 28D, 28E, 29A, 29B, and 31G, but any polarization filter layers 216 Don't have As described above, it is advantageous to inject light in the collimated angle range, preferably substantially perpendicular to the LCD layer 302 to optimize the image output therefrom. The use of post diffusion layer 350 allows output light 253 to provide viewers with an image that does not compromise the contrast of light and the accuracy of color over a wide angular range.

One feature that is preferably controlled in a system comprising a post diffusion layer 350 is the width in the xz-plane of the angular distribution transmitted through the LCD layer 302. Output angle distribution has total width

Smaller is preferred, and it is more preferred that the total width is less than half of this value. In this equation, Δ θ _pd is radians, n _LCD is the average refractive index in the LCD layer 302, p is the repetition period of display pixel rows in the z-direction, and d is the thickness of the LCD layer 302. In a typical LCD used in notebook computers, n _LCD is approximately 1.5, 1 = 0.3 mm, and d = 3 mm. In this example, _{Δθ pd} is preferably 18 degrees or less, and even more preferably the total width is 9 degrees or less. In comparison, Equation (8) calculates the output angular width of the present invention using a flat surface prism redirecting layer, as shown in FIG. 32A (layer 359) or 28B (layer 262). It can be used to In the backlighting system of a typical notebook computer, Φ = 1.3 degrees and n = 1.49. In this example, equation (8) gives an output angle distribution of 18 degrees.

32A illustrates a preferred embodiment of a system 204 with a post diffuser 350 in parallel form disposed to overlap the LCD layer 302. Also included is a holographic angle converter 364 disposed on the back side 211.

In another embodiment shown in FIG. 32B, the refractive / internal reflecting layer 360 includes curved surfaces 362 to narrow the angular distribution in the xz-plane of light incident through the LCD layer 302. As a result, image quality is improved by reducing parallax in the post diffusion layer 350. This embodiment has reflective curved surfaces 362, but as shown in FIG. 32C, flat refractive surfaces may achieve the desired function. In both cases, the curved surfaces 362 preferably have a focal length that is less than the repetition period between the respective surfaces 362. The angular distribution in the xz-plane is preferably narrowed to more than the width given in equation (8), most preferably more than the width given in equation (8). In addition, the plane angles of the redirecting layer 224 are arranged to focus the light output from the other portions of the system 204 onto the desired viewing area. This figure also shows a micro-prism angle conversion layer 274.

FIG. 32C shows a variation of the embodiment of FIG. 32B. The system 204 has an LCD layer arrangement 370 different from the prior art LCD layer arrangement 310 shown in FIG. In particular, a parallel light diffusing layer 372 (diffusion layer, such as a holographic diffuser) is disposed between the LCD layer (layer 316 of FIG. 30) and the second polarization filter layer 322 (layer 314 of FIG. 30). . This arrangement allows the second polarization filter layer 322 to reduce glare that could otherwise be caused by ambient light reflected by the diffusion layer 372. 32C further shows a light redirecting layer 374 that performs an angle narrowing function, such as the reflective curved surfaces 376 shown in FIG. 32B.

While preferred embodiments of the present invention have been disclosed and described above, various modifications and changes can be made by those skilled in the art without departing from the broader scope of the invention specified by the claims given below. You will know clearly.

Claims (78)

(2 correction) An optical apparatus for operating on light from a light source and for selectively outputting light to an observer, wherein the optical device has a wedge-shaped cross section, has an optical refractive index of n1, and is defined in one place to define at least one inclination angle Φ. A base layer having a first and a second side, wherein the base layer further comprises a backing over the first and second sides, wherein light reflected therein is at least one of the first and second layer sides. The light is emitted from the base layer when the angle to the normal is reduced such that the angle of incidence is less than the critical angle θ c for the normal; First layer means comprising a layer having a refractive index disposed over said second surface over said second surface with respect to said base layer, wherein said light in said base layer is at said interface between said base layer and said refractive index n2 layer; when having an angle of incidence characteristic less than θ c, makes it possible for the light to be incident on the first layer means after being output from the base layer; And second layer means for preferentially outputting light in a first polarization state relative to a second polarization state, said second layer means being disposed beyond said second face with respect to said base layer, said second layer means also And capable of reflecting at least a portion of the light having the second polarization state. (Correction) The optical device according to claim 1, further comprising light redirecting means for controlling the angular range of the light output from the optical device. (Correction) The optical device according to claim 1, wherein the base layer includes an additional layer bonded thereto. (Correction) The optical device according to claim 1, further comprising light conversion means for converting light in the second polarization state into light in the first polarization state. (Correction) The optical device according to claim 4, wherein the second layer means is disposed opposite the base layer with respect to the changing means. (Twice correction) The apparatus according to claim 4, further comprising light redirecting means for controlling an angular range of light output from the optical device, wherein the second layer means is the same side of the base layer as the light redirecting means. And is disposed closer to the base layer than to the light redirecting means. (Correct) The method of claim 1, wherein at least one of the first and second layer means comprises light conversion means for at least partially converting light in one polarization state into light in another polarization state. Optical device. (Correction) The optical device according to claim 1, further comprising light redirecting means for changing the angle of light output to the observer. 9. An optical apparatus according to claim 8, wherein said light redirecting means further comprises means for controlling the angular range of light output. (Correct) The optical device according to claim 8, further comprising conversion means for at least partially converting light in one polarization state into light in another polarization state. (Correction) The method of claim 1, further comprising at least one intermediate layer disposed between the base layer and the first layer means, wherein the intermediate layer allows at least a portion of the light to pass through, and wherein the first layer means is at least air Optical device comprising a gap. (Correction) The optical device according to claim 10, wherein the conversion means comprises a birefringent layer. (Correction) The method according to claim 1, wherein the first layer means is (a) spaced farther from the second surface than the second layer means, and (b) disposed closer to the second surface than the second layer means. Optical device, characterized in that. (Correction) The optical device according to claim 1, further comprising a liquid crystal display disposed adjacent to the device, wherein light is redirected to the display by the optical device. The optical device according to claim 1, wherein said first layer means comprises an air gap. (Correction) An optical apparatus for acting on light from a light source and selectively outputting light to an observer, the optical device having a wedge-shaped cross section, having an optical refractive index of n ₁ and defining at least one inclination angle? A base layer having a first and a second side, wherein the base layer further comprises a backing over the first and second sides, wherein light reflected therein is at least one of the first and second layer sides. The light is emitted from the base layer when the angle to the normal is reduced such that the angle of incidence is less than the critical angle θ c for the normal; And layer means coupled to the base layer, the layer means for preferentially outputting light in a first polarization state relative to a second polarization state, wherein the layer means may also reflect at least a portion of the light having the second polarization state. Optical device comprising a. The optical device according to claim 16, wherein the layer means comprises a layer of refractive index n ₂ less than n ₁ . 18. The optical device according to claim 17, wherein the layer means is directly bonded to the base layer. 18. The apparatus of claim 17, wherein said layer means comprises an air gap. (Twice correction) The method of claim 17, wherein the layer means comprises light conversion means for at least partially converting light in one polarization state into light in another polarization state, and also controlling the angular output range of light to the observer. Optical redirecting means for acting on the light so as to act on the light. 21. The optical device according to claim 20, wherein the light conversion means and the light redirecting layer means are disposed adjacent to each other. 21. The optical device according to claim 20, wherein the light converting means comprises a birefringent layer. 23. The optical device according to claim 22, wherein the birefringent layer is disposed on one side of the base layer as opposed to the light redirecting layer means. (Twice correction) The method according to claim 17, wherein the layer means includes a birefringent layer, conversion means for converting light in the second polarization state into light in the first polarization state, and an angular output range of light to an observer. Optical redirecting means for acting on the light to control. 25. The optical device according to claim 24, wherein the light redirecting layer means is disposed farther from the base layer than the birefringence layer and the converting means. 27. The optical device according to claim 25, wherein the conversion means is disposed closer to the base layer than to the birefringence layer. (Twice correction) The method according to claim 17, wherein the layer means is also light in the first polarization state transmitted through the first face of the base layer, and the light transmitted through the second face of the base layer. Providing a portion of light in a second polarization state. (Twice Correction) An optical apparatus for acting on light from a light source to selectively output light to an observer, the optical device having a wedge-shaped cross section, having an optical refractive index of n1 and defining at least one inclination angle Φ; A base layer having a second surface, the base layer further comprising a rear surface extending over the first and second surfaces, wherein light reflected therein is angled with respect to a normal to at least one of the first and second layer surfaces The light is emitted from the base layer when the angle of incidence decreases so that the angle of incidence is less than the critical angle θ c with respect to the normal; First layer means comprising an air gap disposed beyond the second surface with respect to the base layer, wherein the light in the base layer has an incident angle characteristic less than the critical angle θ c at an interface between the base layer and the air gap When it is possible for the light to be incident from the base gap after being output from the base layer; Second layer means for preferentially outputting light in a first polarization state relative to a second polarization state, said second layer means being disposed beyond said second surface with respect to said base layer, said second layer means further May reflect at least a portion of light having a second polarization state; And light redirecting means for acting on the light passing through the base layer to enable the light to be output from the device. (Correction) The optical device according to claim 28, wherein the redirecting means includes means for acting on the light passing through the second layer means to control the output angle of the light. (Correction) The optical device according to claim 29, wherein the light redirecting means acts on the reflected light to redirect the reflected light toward the second layer means. (Twice correction) The optical apparatus according to claim 30, wherein the light redirecting means is disposed beyond an upper surface with respect to the base layer. 32. The optical device of claim 31 wherein the light redirecting means comprises at least a reflective layer. (Twice Correction) An optical apparatus for selectively outputting light to an observer by acting on light from a light source, the optical device having a wedge-shaped cross section and having an optical refractive index of n1 and gathered together to define at least one inclination angle Ψ. A base layer having first and second faces, the base layer further comprising a backing over the first and second faces, wherein light reflected therein is normal to at least one of the first and second layer faces The light is emitted from the base layer when the angle to is reduced such that the angle of incidence is less than the critical angle θ c with respect to the normal; First layer means comprising an air gap disposed at least beyond the first surface with respect to the base layer, the angle of incidence of the light in the base layer being less than the critical angle θ c at the interface between the base layer and the air gap layer When having said light, allowing said light to enter said first layer means after being output from said base layer; And second layer means for preferentially outputting light in a first polarization state compared to a second polarization state, said second layer means being disposed beyond said second face with respect to said base layer, said second layer means being air Can include at least a gap and reflect at least a portion of light having the second polarization state; Optical device comprising a. 34. The optical device of claim 33, further comprising a redirecting layer bearing the first layer, wherein the redirecting layer transmits light toward the viewer over a controlled angular range. (Correct) The method of claim 33, wherein the second layer means further comprises conversion means for converting at least a portion of the light of the second polarization state to provide light of the first polarization state to an observer. Optical device. (Correction) The optical device according to claim 33, wherein the light includes at least one of linearly polarized light, circularly polarized light, and elliptical polarized light. 36. The optical device of claim 35, wherein the second layer means converts light in the second polarization state into light in the first polarization state with an efficiency of at least 10%. 34. The optical device of claim 33, wherein the second layer means is transmitted to light having both the first and second polarization states. (Correction) The method according to claim 33, wherein the second layer means generates a change in the angular distribution of the light smaller than 10% as output to the observer for light incident at an angle x with respect to the plane normal, as follows. Optical device made with. Where n ₁ = refractive index of the base layer and n ₂ = refractive index of the first layer means. (Correction) The optical device according to claim 33, further comprising a third layer means disposed between the base layer and the observer and for converting light in one polarization state into light in another polarization state. . (Correction) The optical device according to claim 40, wherein the third layer means further comprises a liquid crystal layer electrically activated to convert the polarization of the light passing from one polarization state to another. (Correction) The air gap layer according to claim 33, wherein an air gap layer is provided between the liquid crystal layer and a separation layer portion forming the third layer means for converting light from the first polarization state to the second polarization state. It further comprises an optical device. (Correction) The optical device according to claim 35, wherein the polarization state converting means is birefringent such that the refractive index is n? 1.4, the thickness is? 5 m, and? N> 0.05. (Correction) The optical device according to claim 33, wherein the birefringent second layer means comprises at least one of a biaxially oriented layer and a short sided oriented layer of birefringent material. (Correction) The optical device according to claim 43, wherein the birefringent second layer means is selected from the group consisting of polyester, acrylic and polycarbonide materials. (Twice correction) An optical device for selectively outputting light to an observer by acting on light from a light source, the optical device having a wedge-shaped cross section and having an optical refractive index of n1 and gathered together to define at least one inclination angle Ψ. A base layer having first and second faces, the base layer further comprising a backing over the first and second faces, wherein light reflected therein is normal to at least one of the first and second layer faces The light is emitted from the base layer when the angle to is reduced such that the angle of incidence is less than the critical angle θ c with respect to the normal; First layer means including an air gap and disposed over at least one of said first and second surfaces relative to said base layer, said first layer means having an optical index of refraction n2 and allowing transmission of light received from said base layer; And conversion layer means for converting light in one polarization state into another polarization state, wherein the conversion layer means is disposed on at least one of the top or the bottom of the base layer. 47. The optical device of claim 46, further comprising light redirecting means present in at least one of the upper and lower portions of the first layer means for selectively redirecting light output from the first layer means. . (Twice correction) The method according to claim 46, further comprising a reflecting layer that is present beyond the second surface with respect to the base layer to reflect light of the second polarization state received from the base layer. Optical device made with. (Correction) The optical device according to claim 46, further comprising second layer means for preferentially transmitting light in one polarization state to light in another polarization state. (Correction) 49. The apparatus of claim 48, further comprising means on the reflective layer for the base layer to rotate light in the second polarization state to provide light in the first polarization state output to an observer. Optical device made with. (Correction) 51. The apparatus according to claim 50, further comprising: third layer means disposed between the first layer and the observer and for converting light in the first polarization state into light having an LCD good polarization state. Optical device made with. The optical device according to claim 51, wherein said third layer means comprises a birefringent layer. (Correction) An optical device for selectively outputting light to an observer by acting on light from a light source, the optical device having a wedge-shaped cross section, having an optical refractive index of n1 and being gathered in one place to define at least one tilt angle Ψ And a base layer having a second surface, the base layer further comprising a back surface extending over the first and second surfaces, wherein light reflected therein is directed to at least one normal of the first and second layer surfaces. The light is emitted from the base layer when the angle is reduced such that the angle of incidence is less than the critical angle θ c with respect to the normal; First layer means comprising an air gap over said first layer and said second layer relative to said base layer, said first layer means being said critical angle at said interface between said base layer and said total means; when having an angle of incidence characteristic less than θ c, enables the light to enter the layer means from the base layer; Light redirecting means for acting on light passing through the base layer and outputting the light towards an observer; And second layer means disposed at a layer position relative to the base layer, the layer beyond the first face and a layer beyond the light redirecting means with respect to the base layer, wherein the second layer means are second relative to a second polarization state. Preferentially transmitting light in one polarization state and preferentially reflecting light in the second polarization state; Optical device comprising a. (Twice correction) 54. The apparatus of claim 53, wherein the second layer means is disposed beyond the first face with respect to the base layer, and the optical device is provided with the second layer means and the first face with respect to the base layer. And other light redirecting means disposed above both. 54. The apparatus of claim 53, wherein the redirecting means comprises at least one of a reflective layer capable of reflecting light and a transmissive layer capable of modifying the angular distribution of light passing therethrough. 54. The apparatus of claim 53, wherein the second layer means is disposed on a first means of the light redirecting means with respect to the base layer, and an air gap is disposed between the base layer and the second layer means. And another air gap is arranged between the two layer means and the second means of the light redirecting means. (Twice correction) An optical device for selectively outputting light to an observer by acting on light from a light source, the optical device having a wedge-shaped cross section and having an optical refractive index of n1 and gathered together to define at least one inclination angle Ψ. A base layer having first and second sides, the base layer further comprising a backing over the first and second surfaces, wherein light reflected therein is at least one of the first and second layer surfaces; The light is emitted from the base layer when the angle for one normal is reduced such that the angle of incidence is less than the critical angle θ c for the normal; A first including an air gap, disposed over at least one of the first surface relative to the base layer and over the base layer surface relative to the base layer, the optical layer having an optical index of refraction n2 and allowing transmission of light received from the base layer Layer means; Second layer means for preferentially transmitting light in a first polarization state relative to a second polarization state, said second layer means being disposed at least over (a) said first surface and said first layer means relative to said base layer; Or (b) allowing reflection of at least a portion of said light disposed over said second face and said first layer means and having said second polarization state; Light redirecting means acting on the light reflected by the second layer means and redirecting back to the second layer means; And third layer means for converting at least a portion of said light in said second polarization state into light in said first polarization state. (Correction) The optical device according to claim 57, wherein the light redirecting means includes a reflecting layer disposed below the second surface of the base layer, and the second layer means is disposed above the base layer. . 59. The optical device according to claim 57, wherein said third layer means is disposed between said second layer means and said light redirecting means. 59. The optical device according to claim 58, wherein the third layer means is disposed between the reflective layer and the second layer means. (Twice correction) The optical apparatus according to claim 60, wherein the third layer means is disposed over the first surface together with the second layer means. (Correction) The optical device according to claim 60, wherein the third layer means is disposed below the second surface together with the reflective layer. 59. The optical device of claim 57, wherein the second layer means comprises a plurality of layers of alternating high or low refractive index material. The optical device according to claim 63, wherein the refractive indices n _H (high refractive index) and n _L (low refractive index) satisfy the following conditions. tan θ _H = n _H / n _L ; tan θ _L = n _L / n _H ; And n ² _H n ² _L n ² _H + n ² _L 65. The optical device of claim 64, wherein the thickness of each of the plurality of layers is about one quarter of the wavelength of light in the layers. 65. The optical device of claim 64, wherein the thickness of each of the plurality of layers is at least twice the wavelength of light in the layers. (Twice Correction) An optical apparatus for acting on light from a light source and selectively outputting light to an observer, wherein the optical device has a wedge-shaped cross section, has an optical refractive index of n1, and is defined so as to define at least one inclination angle Ψ. A base layer having a first and a second side, wherein the base layer further comprises a backing over the first and second side, wherein light reflected therein is at least one of the first and second layer sides The light is emitted from the base layer when the angle for at least one normal is reduced such that the angle of incidence is less than the critical angle θ c for the normal; Layer means for preferentially outputting light in a first polarization state relative to a second polarization state, said layer means comprising first filter layer means for filtering said light to preferentially pass said light in a first polarization state And converting means for converting at least a portion of the light in the second polarization state into the light in the first polarization state; A liquid crystal display layer arranged to receive the light in a first polarization state and output the light to an observer; And light for outputting light to an observer over a wide range of viewing angles without degrading image quality by diffusing the light output from the layer means and the liquid crystal display layer to widen the light with a narrow angular distribution in the plane. And diffusing means. 68. The optical device according to claim 67, wherein said layer means comprises at least one polarizing filter layer and at least one optical polarization converting layer. 68. The optical device of claim 67 wherein the light diffusing means comprises a parallel light diffuser. (Correction) The optical device according to claim 67, wherein the light diffusing means includes a light redirecting layer having a prism face. (Twice Correction) An optical apparatus for selectively outputting light to an observer by acting on light from a light source, the optical device having a wedge-shaped cross section and having an optical refractive index of n1 and gathered together to define at least one inclination angle Ψ. A base layer having first and second sides, the base layer further comprising a backing over the first and second surfaces, wherein light reflected therein is at least one of the first and second layer surfaces; The light exits from the base case when the angle for one normal is reduced such that the angle of incidence is less than the critical angle θ c for the normal; First layer means comprising a layer having a refractive index disposed over said second surface over said second surface with respect to said base layer, wherein said light in said base layer is at said interface between said base layer and said refractive index n2 layer; when having an angle of incidence characteristic less than θ c, makes it possible for the light to be incident on the first layer means after being output from the base layer; An liquid crystal display layer arranged to receive the light in a first polarization state and output the light to an observer; And light diffusing means for diffusing the light output from the layer means and the liquid crystal display layer to widen the light having a narrow angular distribution in a plane, thereby outputting light to an observer over a wide range of viewing angles without degrading image quality. Optical device comprising a. 72. The optical device of claim 71 further comprising at least one of a reflective layer, a light redirecting layer, and a transverse diffuser disposed closer to the base layer than the liquid crystal display layer. (Twice correction) An optical apparatus for acting on light from a light source and selectively outputting light to an observer, wherein the optical device has a wedge-shaped cross section, has an optical refractive index of n1, and is defined in one place to define at least one inclination angle Ψ. A base layer having a first and a second side, wherein the base layer further comprises a backing over the first and second side, wherein light reflected therein is at least one of the first and second layer sides The light exits from the base case when the angle for at least one normal is reduced such that the angle of incidence is less than the critical angle θ c for the normal; First layer means comprising a layer having a refractive index disposed over said second surface over said second surface with respect to said base layer, wherein said light in said base layer is at said interface between said base layer and said refractive index n2 layer; when having an angle of incidence characteristic less than θ c, makes it possible for the light to be incident on the first layer means after being output from the base layer; Second layer means for preferentially outputting light in a first polarization state relative to a second polarization state, said second layer means being disposed beyond said second surface with respect to said base layer, said second layer means further Capable of reflecting at least a portion of the light having a second polarization state—light redirecting means for controlling the angular range of light output from the device; And a liquid crystal display layer arranged to receive the light in the first polarization state and output the light to an observer. 74. The optical device of claim 73, wherein the second layer means comprises at least one of a polarization filter layer and a polarization converting layer. (Twice Correction) An optical apparatus for selectively outputting light to an observer by acting on light from a light source, the optical device having a wedge-shaped cross section and having an optical refractive index of n1 and gathered together to define at least one inclination angle Ψ. A base layer having a first and a second surface, the base layer further comprising a backing over the first and second surfaces, wherein light reflected therein is at least one of the at least one of the first and second layer surfaces The light is emitted from the base layer when the angle for one normal is reduced such that the angle of incidence is less than the critical angle θ c for the normal; Layer means including an air gap, disposed over at least one of said first surface and said second surface relative to said base layer, said layer means having an optical index of refraction n2 and allowing transmission of light received from said base layer; Conversion layer means for converting light in one polarization state into light in another polarization state, wherein the conversion layer means is disposed on at least one of the top or the bottom of the base layer; And a liquid crystal display layer arranged to receive the light in the first polarization state and output the light to an observer. (Correction) The optical apparatus according to claim 75, further comprising light diffusing means for diffusing the light output from the layer means and the liquid crystal display layer to widen the light having a narrow angle distribution selected. 76. The optical device according to claim 75, wherein said layer means comprises at least one polarizing filter layer and at least one optical polarization converting layer. 76. The optical device of claim 75, wherein the light redirecting means comprises at least one of a light redirecting layer disposed above or below the base layer and a light redirecting layer disposed adjacent the back surface.