CN102341748A

CN102341748A - Light guide system with controlled output for light extraction

Info

Publication number: CN102341748A
Application number: CN2009801562709A
Authority: CN
Inventors: 布莱恩·爱德华·理查德森
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-01-02
Filing date: 2009-12-31
Publication date: 2012-02-01
Also published as: KR20110139193A; JP2012514835A; WO2010077367A3; CN102395922A; KR20110139194A; EP2384454A1; JP2012514761A; WO2010077367A2; WO2010077363A1; EP2384455A2

Abstract

A light guide with optics guides light exiting the light guide. This device achieves precise control of reflected light by extracting it from a limited area of the light guide. The configuration of the reflector used for selective extraction determines the characteristics of the output light. The reflector can be located on the side of the light guide opposite the output side.

Description

Light guide system with controlled output for extracting light

Cross Reference to Related Applications

The present application claims priority of U.S. patent application No. 12/319,172 entitled "optical System for Light Guide With Controlled Output" filed on 1/2/2009 and U.S. patent application No. 12/319,171 entitled "TIR Switched Flat Panel Display" filed on 1/2/2009, all of which are incorporated herein by reference.

Technical Field

The present invention relates generally to light display devices and, more particularly, may include an optical system for controlling the direction of propagation of light as it exits a light guide.

Background

Many products require an optical system to spread the light over a large area and to control the direction of the light as it exits the system. Recent improvements in LED performance coupled with simultaneous reduction in production costs have made LEDs a more viable option for many applications. However, many applications, such as LCD backlights, signage with backlights, overhead lights, and automotive lighting, require that the bundled light generated by the LEDs be spread over a larger area while also controlling the direction of the light. These applications require improved optical systems to provide the desired light control.

Displays based on LCD technology have been developed for decades. Many patent documents based on improvements to the basic technology are now available. However, the prior art displays have several disadvantages. The main drawback of the prior art devices is excessive energy consumption. LCD televisions for 65 "diagonal HDTV (high definition television) typically consume about half a kilowatt. This is due to the low efficiency of the technology.

One way to improve the efficiency of an LCD display is to direct as much of the available light from the light source to the area most visible to the viewer. For handheld display devices where power consumption is obviously an important consideration, it is desirable that the angle at which the light is directed to the viewer is narrow.

In a stand-up application such as a television, it is desirable to have the highest intensity segment of light projected in a direction perpendicular to the surface of the display. It is also important to provide a large amount of light to the left and right of the normal. This is desirable for viewers who are not in the optimal viewing position (perpendicular to the screen). It is also desirable in these applications to reduce the amount of light projected at angles greater or less than normal to the screen. If the light, which is normally directed in an off-normal direction, is redirected to a preferred angle, the intensity of the light transmitted in the preferred direction will be greater.

Three sets of prior art documents have proposed controlling the light of LCD type displays. Among these prior art documents, prismatic "brightness enhancement films" (BEFs) are the most common type. An example of a BEF is U.S. Pat. No. 5,467,208 "Liquid Crystal Display" to Shozo Kokawa et al, published 11, 14, 1995. This document discusses the prior art of prismatic films and discloses an improvement over the prior art. One disadvantage of prismatic films is that they have only limited control over the angle of light output. The change in the prism characteristics only makes a slight change in the light output. Prismatic films are also limited to two-dimensional structures. If the application requires control of the light in three dimensions, at least two BEFs must be used.

A second type of prior art is exemplified by Akira Yamaguchi, U.S. patent 6,421,103, "Liquid Crystal Display apparatus", published on 16.7.2002. The Yamaguchi document discloses another means for controlling light as it enters the LED board. This patent discloses a light source, a substrate (not acting as a light guide), an aperture and a reflective region on the substrate. Light is reflected by the reflective surface or passes through the aperture. Light passing through the aperture is captured by the lens to control the direction of the light. Yamaguchi teaches the limitation of output light angle to concentrate more light directly at the viewer of an LCD-type display. The Yamaguchi device provides more control over the output light than is available with BEF devices. However, the Yamaguchi device suffers from its extremely low efficiency. The light must be reflected off the reflective surface multiple times before it exits the aperture. Even when the reflecting surface is made of a material having a high reflectance, the loss of strength is considerable. Thus, while the light control of the invention is superior to that of the BEF device, the efficiency is much lower.

U.S. patent No. 5,396,350 to Karl Beeson, published 3, 7, 1995, "Backlighting apparatus. (backlight apparatus...); and Neil Lubart's U.S. patent 7,345,824 "Light Collimating Device", published 3.18.2008; optics for use in a third type of light control of an LED light source arrangement are disclosed. The document of Beeson and Lubart discloses reflective structures on the sides of the light guide. The control range of these reflective structures is limited and not equivalent to the control provided by devices such as Yamaguchi. Furthermore, the reflective structures are positioned very close to the LCD panel, which makes defects in their output readily visible to a viewer of the display.

Disclosure of Invention

Various aspects include a light guide for guiding light. Some embodiments include an optical system for a light guide that controls the angle of the light as it exits the system. It can be used in many applications, from LCDs to overhead lights. LCD displays are the type used in cellular telephones, laptop computers, computer monitors, televisions, and commercial displays. The light guide may transmit light from the light guide at discrete points and/or over the entire area. The output light of the device can be controlled to be parallel, divergent or convergent using the extraction element in conjunction with the reflector. The reflector may be two-dimensional or three-dimensional.

An advantage of the optical system of the present invention is that it accurately controls the angle of the output light.

Another advantage of the optical system of the present invention is that it transmits light more efficiently with respect to energy consumption than the prior art. A further advantage of the optical system of the present invention is that it is simple in construction and therefore simple and economical to manufacture.

These and other objects and advantages of the present invention will become apparent to those skilled in the art in view of the description of the best presently known mode of carrying out the invention as described herein and illustrated in the accompanying drawings.

Drawings

Fig. 1 is a perspective view of a light guide having an optical device of the present invention.

FIG. 2 is an enlarged partial side view of the light guide with optics shown in FIG. 1.

Fig. 3 shows a three-dimensional type reflector.

Fig. 4 shows a two-dimensional type reflector.

FIG. 5 is a cut-away side view of a light guide, LCD, and end reflector.

FIG. 6 is an enlarged partial side view of a different configuration of an optical system.

FIG. 7 is an enlarged side view of another configuration of an optical system.

Fig. 8 shows an optical system using a diverging reflector.

Fig. 9 shows an enlarged side view of another configuration of the optical system.

Fig. 10 shows an embodiment.

Fig. 11 shows an embodiment.

Detailed Description

Referring first to fig. 1, a light guide assembly 1 of the present invention includes a light guide 2 with a planar surface and a plurality of LEDs 3. The LEDs 3 may be located along a surface, such as the lower edge of the light guide 2. The number of colors of the LEDs 3 and the number of sides of the light guide 2 on which the LEDs 3 are located may be related to the size, shape, and use of the light guide 2. The LEDs 3 may be located on more than one side of the light guide 2. The LEDs 3 may require electronics to drive them at the appropriate level. A person skilled in the art of LED driver electronics can design many different circuits to accomplish this task. The embodiment shown in FIG. 1 generally includes 27 LEDs 3, the LEDs 3 being shown substantially equally spaced along the bottom edge of the light guide 2. It should be appreciated that other types of light sources, such as lasers, incandescent light, fluorescent light, or even natural light, may suffice in place of the LED 3.

The light guide 2 is shown in an enlarged side view in fig. 2. Fig. 2 shows a sample of light 17 emitted from LED 3. The upper ray 10 is shown impinging on the upper surface 11 of the light guide 2. When the contact angle or angle of incidence of the light ray 10 with respect to the surface of the light guide 2 is shallow, the light is reflected from the surface of the light guide 2. This reflection can be determined using the following equation:

A＝arcsine(Ns/NIg)

where NIg is the refractive index of the light guide and Ns is the refractive index of the medium outside the light guide. Angle "a" is the angle from the normal to the light guide surface and is defined by Ns and NIg. The angle of incidence may be defined as 90-A.

For air or another low index material, Ns may be 1.35 or less. For a plastic or glass light guide 2, NIg may be 1.5. The angle a for these values may be about 64 °. The maximum angle of incidence at which light may be totally internally reflected may be about 26.

If light hits a surface of the light guide 2 at an angle larger than a (or smaller than 90 degrees-a), the light will reflect from the surface with Total Internal Reflection (TIR). If the angle of incidence is greater than 90 degrees-A, at least a portion of the light may pass through the surface (e.g., light guide upper surface 11) and may be refracted. In the embodiment shown, the reflected light 13 continues in a downward direction where the light encounters the window to a reflector disposed on the contact dome 14. Preferably, the contact dome 14 has an index of refraction equal to or greater than that of the light guide 2. If the refractive indices of the light guide 2 and the contact dome 14 are the same, the light 13 propagates from the body of the light guide into the contact dome at substantially all angles of incidence. If the refractive indices are slightly different, the light 13 may be refracted. If the refractive indices are much different and the contact dome 14 has a smaller refractive index, light can be reflected from the "window" region. For most applications, it is not desirable to have any TIR of light in the window where the contact dome 14 is in contact with the light guide 2. Selecting a contact dome 14 having an index of refraction equal to or greater than the light guide 2 may help to pass light from the light guide 2 to the contact dome 14. Selecting a contact dome 14 having the same index of refraction as the light guide body can help return light reflected by the contact dome back into the light guide body.

The upper reflected light 13 continues through the contact dome 14 and hits the reflector 15. In some embodiments, the surface of the reflector 15 may be coated with a reflective material to reflect light. The reflective material may be aluminum, silver, dielectric interference type mirrors, or other reflective materials or methods. If the reflector 15 is configured to have an angle that falls within the TIR formula, the reflector 15 may not be coated. Incident light 13 is reflected from the surface of reflector 15.

In some embodiments, the structure of the reflector 15 is at least partially optically isolated from light coming from the light guide 2, but not from the region of the contact window between the light guide 2 and the contact dome 14. In the configuration shown in fig. 2, the isolation is achieved by providing a slight air gap 16 between the light guide 2 and the structure comprising the reflector 15. (see FIG. 9. Another approach discussed below is to install a layer of low refractive index material between the light guide 2 and the structure of the reflector 15.)

In these cases, an angular dependence of the reflectivity may be created, whereby the lower angle light is reflected from the part of the surface with the air gap, while the contact window transmits substantially all incident light to the contact dome 14.

The shape of the reflector 15 may determine the direction in which light is reflected back into the light guide 2 and thus the characteristics of the output light output through the light guide 2. Fig. 2 shows a substantially elliptical reflector 15. The elliptical reflector 15 focuses light to a point or causes light to exit the reflector 15 at multiple angles. If the reflector 15 is parabolic, the light leaving the light guide 2 may be substantially parallel at the contact window close to the "point source" of the reflector. If an elliptical reflector or a parabolic reflector is chosen, the focal point of the reflector may be located at the contact window where the contact dome 14 and the light guide 2 meet. Many other shapes may be used for the reflector 15, the choice depending on the desired angular output of the light.

Referring now to fig. 3, reflector 15 is shown as a three-dimensional type reflector. The reflector 15 can easily be chosen as a two-dimensional line reflector as shown in fig. 4. Furthermore, the choice of which type of reflector 15 to use depends on the application in question. The user may also select a combination of many reflector shapes and may utilize them in a two-dimensional or three-dimensional type configuration. Both two-dimensional and three-dimensional reflectors are shown as arrays of reflectors 15 in fig. 3 and 4. Those skilled in the art will recognize that many other types of reflector arrays may also be used.

Fig. 5 shows an enlarged side view of the light guide 2, the LED3 and the

end reflectors

20 and 21. Light will often pass from the LED3 through the light guide and not reflect from the contact dome 14 in the open position and thus leave the light guide 2. In that case, the light will propagate through the entire length of the light guide 2. When the light reaches the distal end of the light guide 2, i.e. the end opposite the LED3, the light is reflected at the end reflector 21. This reflection redirects the light in the opposite direction through the light guide 2 back to the original LED 3. Preferably, the end reflector 21 is made of a material having a high reflectance. Interference type or metal reflectors are two possible alternatives for the end reflector 21. A third possibility is an angled retro-reflector.

If the light continues to propagate in the light guide 2 without coming into contact with the contact dome 14, the light will reach the starting end of the light guide 2, i.e. the end where the LED3 is located. At this end of the light guide 2, light may impinge on the area between the LEDs 3 or light may impinge on the LEDs 3. When light hits the area between the LEDs 3, the light will be reflected by the end reflector 20. If the light guide 2 has only some LEDs 3, light will almost always reflect off the high reflectivity end reflector 20. In the case where light is reflected from the LED3, the LED3 may absorb a portion of the light, while the remainder of the light will be reflected. The light may propagate up and down the light guide 2 multiple times before it is extracted by the contact dome 14. This may be the case when only some of the contact domes 14 are in contact with a particular light guide assembly 1. If many contact domes 14 are present in the light guide 2, the light will be less likely to generate more than one or two paths along the light guide 2. Even in the case of a large number of reflections due to the light generating multiple paths along the light guide 2, the loss of light will be small. The end reflectors 20, 21 may have a reflection efficiency of 98% or better, and a good quality light guide material absorbs very little light.

In fig. 6, another configuration of the light guide assembly 1 is shown, in which the reflector 15 is hollow, rather than being made of a solid material as is often the case. In this configuration, the contact dome 14 adopts a conical or spherical surface 22, so that when the contact dome is in the open position, the upwardly reflected light 13 passes through the contact dome 14 and continues along a generally straight path toward the surface of the reflector 15. The light guide assembly 1 shown in fig. 6 functions the same as the light guide assembly 1 shown in fig. 2, the only difference being that a hollow reflector 15' is utilized.

Another configuration of the light guide assembly 1 is shown in fig. 7. In the configuration shown in fig. 7, the features of the contact dome 14 are cut into the surface of the light guide 2. In fact, this configuration is the inverse of the configuration shown in FIG. 2. Like the assembly 1 shown in fig. 6, the light guide assembly 1 shown in fig. 7 functions the same as that shown in fig. 2. Ease of manufacture and desired output action may control which reflector configuration is selected for a given application.

Fig. 8 shows a configuration of the light guide assembly 1 in which the output light is divergent as opposed to impinging on the focal point. As described above, the shape of the reflector 15 controls the output action of light. In fig. 8, the shape of the reflector 15 is chosen to scatter the reflected light rays 18 opposite to shining the light towards the focal point. Fig. 9 discloses another method for optically isolating the structure of the reflector 15 from the light guide 2. In the configuration shown in fig. 9, a thin layer 30 of a material of lower refractive index separates the light guide 2 from the structure supporting the reflector 15. The contact dome 14' is simply a hole in the thin layer 30 of lower refractive index.

The thickness of the lower index layer 30 in fig. 9 is not necessarily drawn to scale. In practice, the smaller index layer 30 may be several microns thick. The thin layer 30 may be deposited using a photolithographic process. The reflector 15 and the contact dome 14 "may be molded in direct contact with (e.g., soldered to) the light guide 2 and the lamina 30. A binder may be used as the lower index material 30. The selection of a binder as the lower index of refraction material 30 may be beneficial to the manufacturing process.

Fig. 10 shows an embodiment. Light 1000 may be transmitted through light guide 1010. The light guide 1010 may have a first index of refraction and may include one or more surfaces between the light guide 1010 and another medium (e.g., a solid, liquid, air, or even a vacuum) having a second index of refraction. These surfaces may be generally flat, curved, elongated (e.g., having a dimension much larger than another dimension, such as 10 or even 100 times larger), and other shapes. The light guide 1010 can include a first surface 1020 configured to receive light from a light source (not shown), a second surface 1030 (e.g., from which light can exit the light guide 1010), and a third surface 1040 associated with various light management devices. Light guide 1010 may include one or more fourth surfaces 1050. In some cases, fourth surface 1050 may receive light from a light source. In some cases, fourth surface 1050 may be at least partially mirrored. In some embodiments, the fourth surface 1050 may include a total reflection mirror that may reflect back to the light guide 1010 reflected light from within the light guide 1010 that is incident on the fourth surface 1050.

Light guide 1010 is characterized by one or more lengths, such as length 1012 and thickness 1014. The length may be selected according to various application specifications (e.g., cell phone screen, home lighting form factor, television size, etc.). The length may be selected according to various material properties (e.g., thickness 1014 may be selected according to the index of refraction of light guide 1014, the angle in light guide 1010 associated with TIR, the specification of the quality of the light used to exit light guide 1010 (e.g., the requirement that the light be within a few degrees of normal to second surface 1030), etc.).

Light from the light source may be transmitted into the light guide 1010 via the first surface 1020. The first surface 1020 may be at least partially reflective (e.g., a half mirror) and may be configured to reflect light reaching the first surface 1020 from within the light guide 1010 back into the light guide 1010. The first surface 1020 may be flat, curved, or otherwise shaped. First surface 1020 may be disposed at an angle 1022 with respect to one or more other surfaces of light guide 1010. The angle 1022 may be between 45 ° and 135 °, between 70 ° and 110 °, and/or between 80 ° and 100 °. In some cases, angle 1022 may be selected according to various predicted angles of internal reflection within light guide 1010.

Light from the light source may be transmitted into the light guide 1010 via the fourth surface 1050. Fourth surface 1050 may be at least partially reflective (e.g., a half mirror) and may be configured to reflect light reaching fourth surface 1050 from within light guide 1010 back into light guide 1010. Fourth surface 1050 may be flat, curved, or otherwise shaped. Fourth surface 1050 may be disposed at an angle 1052 relative to one or more other surfaces of light guide 1010. The angle 1052 may be between 45 ° and 135 °, between 70 ° and 110 °, and/or between 80 ° and 100 °. In some cases, angle 1052 may be selected according to various predicted angles of internal reflection within light guide 1010.

Some surfaces (e.g., first surface 1020 and/or fourth surface 1050) may be configured to reflect light (incident on the surface from within light guide 1010) back into light guide 1010 in one or more preferred directions. In some cases, the surface may reflect light to minimize such undesired transmission of the reflected light out of the light guide 1010. In some cases, the light may be reflected at angles less than an angle of incidence associated with TIR from another surface (such as second surface 1030 and/or third surface 1040).

Some surfaces (e.g., third surface 1040 and/or optionally second surface 1030) may include "mirrors" whose reflectivity depends on the angle of incidence of incident light (e.g., from within light guide 1010). The angular dependence of the reflectivity can be formed by controlling the refractive index on either side of the surface. The angular dependence of the reflectivity can also be formed by other methods, such as nanostructures of the surface, the use of surface coatings, and the like. In some cases, the surface is designed to reflect incident light at a lower angle of incidence (e.g., less than 45 °, less than 30 °, less than 20 °, or even less than 10 °). In some cases, the surface is designed such that incident light can pass through the surface at higher angles of incidence (e.g., normal to the surface, within 2 ° from normal, within 10 ° from normal, and/or within 20 ° from normal).

The surface of the light guide 1010 may include one or more windows 1060. In the example shown in fig. 10, the window 1060 is disposed within the third surface 1040 and light exits the light guide 1010 via the second surface 1030. Some embodiments include tens, hundreds, thousands, millions, or even billions of windows 1060. Certain embodiments include one, two, three, five, or ten windows 1060. Window 1060 can be characterized by one or more dimensions 1062, such as a length, a width, a radius, and/or other dimensions that characterize aspects of window 1060. The features of window 1060 may be "transparent" to substantially all incident light and may transmit light from within the "body" of light guide 1010 to other structures (such as contact domes, reflectors, etc.).

The reflector may take a variety of shapes (parabolic, elliptical, linear, curved, flat, and other shapes). The window may have different reflectors associated with different directions of incident light. For example, the shape of reflector 1070 may be selected based on a preferred reception of light incident from a direction associated with first surface 1020, while reflector 1072 may be selected based on a preferred reception of light incident from a direction associated with fourth surface 1050. A window 1060 is provided for passing light through the window to the one or more reflectors. In the example shown in fig. 10,

reflectors

1070 and 1072 are disposed at positions that reflect incident light. The reflector may be generally a fully reflective mirror (e.g., fully reflective and/or specularly reflective). The reflector may be characterized by one or more dimensions. In the example shown in fig. 10, the reflectors may be characterized by

dimensions

1074, 1076, and 1078, and the features may optionally be other dimensions (e.g., perpendicular to the page).

In the example shown in fig. 10, third surface 1040 functions as an angle-dependent mirror by virtue of the reflectivity caused by the different indices of refraction on either side of the surface. Such an implementation may include

reflectors

1070 and 1072 disposed on contact dome 1080 made of the same material as light guide 1010. The reflective portion of the third surface 1040 can include an air gap, while the window 1060 can include an optically transparent junction between the contact dome 1080 and the "body" of the light guide 1010, as described above. Light having a shallow angle of incidence on the third surface 1040 (i.e., having an angle greater than a with respect to normal) may be reflected from the third surface 1040.

Light (e.g., light 1000) passing through window 1060 may be reflected back to a surface (e.g., third surface 1040) by a reflector (e.g., reflector 1070). Such reflection may result in the reflected light 1000 having a larger angle of incidence relative to the third surface 1040 and/or the second surface 1030, which may result in the light passing out of the light guide 1010 (e.g., via the second surface 1030). These angles are schematically illustrated in fig. 10 by means of angles relative to the surface normal that are smaller than the TIR angle a.

Various dimensions may be selected according to application requirements (e.g., 1062, 1070, 1074, 1014, etc.). For example, as the radius 1062 of the circular window 1060 decreases, light passing through the window 1060 may increasingly behave as if reaching the reflector 1070 from a "point source," which may provide for the use of a particular geometry of the reflector 1070 (e.g., parabolic), which results in light exiting the light guide 1010 through the second surface 1030 at an angle substantially perpendicular to the second surface 1030.

Fig. 11 shows an embodiment. Light 1100 may be guided by light guide 1110. Light guide 1110 may include surface 1130 and surface 1140. Surface 1140 may be at least partially reflective and may reflect incident light that arrives at an angle of incidence that is shallower (relative to the surface) or greater (relative to the surface normal) than the angle a associated with TIR.

The surface 1140 may include a window 1160, which may be in optical communication with the reflector 1170. Reflector 1170 may be characterized by dimension 1172. In some embodiments, dimension 1172 may be approximately equal to a pixel size of a display device configured to display light guided by light guide 1110 (e.g., in the range of 10%, 5%, 2%, or even 1% of the pixel size). In some embodiments, the light source provides light that is guided by the light guide 1110. In some cases, each pixel associated with a display device can be associated with a window 1160 and/or a reflector 1170.

Surface 1130 may include "lenses" or other shapes associated with light transmission through surface 1130. In some cases, the shape of the lens may be selected to modify the angle of transmission of light from surface 1130. For example, moderately divergent light can be modified to become parallel and/or perpendicular to a plane associated with light guide 1100.

The above disclosure is not intended to be limiting. Those skilled in the art will readily observe that numerous modifications and variations may be made to the device while retaining the teachings of the invention. Accordingly, the above disclosure should be understood as limited only by the limitations of the following claims.

Claims

1. A light guide 1010 comprising:

a first surface 1020 configured to receive light 1000 from a light source;

second surface 1030; and

A third surface 1040 having a window 1060 in optical communication with a reflector 1070 having a shape configured to reflect at least a portion of the light 1000 from within the light guide 1010 such that at least a portion of the reflected light 1000 The angle transmitted through the second surface 1030 is incident on the reflector 1070 .

2. The light guide 1010 of claim 1 , wherein any one of the first surface 1020 and the third surface 1040 reflects light arriving from within the light guide 1010 at an angle of incidence that is less than the ratio of the angle of incidence to The angle associated with total internal reflection of light passing through the surface within the light guide 1010 is small.

3. The light guide 1010 of any one of the preceding claims, wherein the window is transparent to light reaching the window from any angle.

4. The light guide 1010 of any one of the preceding claims, wherein the first dimension 1012 is more than 100 times larger than the second dimension 1014.

5. The light guide 1010 of any one of the preceding claims, wherein the first dimension associated with the window 1060 is more than 10 times larger than the second dimension associated with the window 1060.

6. The light guide 1010 of any one of the preceding claims, wherein a first dimension associated with reflector 1070 is more than 10 times greater than a second dimension associated with reflector 1070.

7. The light guide 1010 according to any one of claims 5 or 6, wherein the first dimension is more than 100 times larger than the corresponding second dimension.

8. The light guide 1010 of any one of claims 1 to 5, wherein the window 1060 is circular.

9. The light guide 1010 of any one of the preceding claims, wherein at least a portion of the curvature of the reflector 1070 is characterized by a parabolic shape.

10. The light guide 1010 of any one of the preceding claims, wherein at least a portion of the curvature of the reflector 1070 is characterized by an ellipse.

11. The light guide 1010 of any one of the preceding claims, wherein at least a portion of the curvature of the reflector 1070 is characterized by being flat.

12. The light guide 1010 of any preceding claim, wherein the first dimension 1078 associated with the reflector 1070 is more than 10 times smaller than the first dimension 1012 associated with the light guide 1010.

13. The light guide 1010 of any one of the preceding claims, wherein the first dimension 1074 associated with the reflector 1070 is within 10 times the first dimension 1014 associated with the light guide 1010.

14. The light guide 1010 of any one of the preceding claims, further comprising two or more windows 1060 in corresponding optical communication with a reflector 1070 having a structure configured to reflect The shape of at least a portion of light 1000 that is incident on said reflector 1070 from within light guide 1010 at an angle such that at least a portion of reflected light 1000 is transmitted through said second surface 1030 .

15. The light guide 1010 of any one of the preceding claims, wherein the reflector 1070 comprises a first portion having a first shape and a second portion having a second shape.

16. The light guide 1010 of any one of the preceding claims, wherein any surface includes an interface with a region having the second refractive index.

17. The light guide 1010 of claim 16, wherein the second index of refraction is less than the first index of refraction.

18. The light guide 1010 according to any one of the preceding claims, wherein the light transmitted via the second surface 1030 is transmitted at an angle within 20° of the normal to the second surface 1030.

19. The light guide 1010 of claim 18, wherein the angle is within 10° of the normal.

20. The light guide 1010 of claim 19, wherein the angle is within 5° of the normal.

21. A light guide 1010 as claimed in any one of the preceding claims, wherein the dimensions are selected to be approximately equal to the pixel size associated with a display screen comprising the light guide 1010.

22. A light guide system comprising:

light source; and

A light guide according to any one of the preceding claims.

23. A display device comprising a light guide according to any one of claims 1 to 21.

24. A method of guiding light comprising using a light guide according to any one of claims 1 to 21.

25. A method of manufacturing a light guide, the method comprising:

forming the first body from a material having a first index of refraction;

attaching one or more second bodies to the first body, each second body having:

second refractive index;

an optically transparent connection to said first body formed by a window of contact between said first and second bodies; and

A reflector having a shape configured to transmit at least a portion of light from the first body through the window into the second body such that reflected light passes through the first body The transmitted incident angle is reflected back into the first body.

26. The method of claim 25, wherein the first and second indices of refraction are the same.

27. A light guiding system comprising:

light guides in which light propagates by total internal reflection,

at least one optical element providing selective extraction of light from the light guide, and

at least one reflector in the optical element at least partially optically isolated from the light guide except for a window between the optical element and the light guide; wherein,

When light is extracted from the light guide, the light shines in a predetermined direction and pattern.

28. The light guide system of claim 27, wherein:

Extraction of light is initiated by bringing the optical element into physical contact with the light guide.

29. The light guide system of claim 27, wherein:

The configuration of the reflector controls the predetermined direction and pattern.

30. The light guide system of claim 29, wherein:

The reflector is a hollow element.

31. The light guide system of claim 27, wherein:

The contact portion of the optical element is integral with the body to the light guide.

32. The light guide system of claim 27, wherein:

The reflector is shaped to diverge the output light.

33. The light guide system of claim 27, wherein:

The optical isolation is achieved by an air gap.

34. The light guide system of claim 27, wherein:

Said optical isolation is achieved by a thin layer of material with a low refractive index.

35. The light guide system of claim 27, wherein:

Light reflected from the reflector passes through the light guide after exiting the reflector.

36. The light guide system of claim 27, wherein:

The reflector is a two-dimensional reflector.

37. The light guide system of claim 27, wherein:

The reflector is a three-dimensional reflector.

38. A method of manufacturing a display device comprising the method of claim 25.