KR20070115882A - Etendue efficient combination of multiple light sources - Google Patents

Abstract

A multi-colored illumination system comprising a beam combiner. The beam combiner comprises two triangular prisms and a filter for transmitting a first light and reflecting a second light, each light having a different wavelength. The beam combiner combines the transmitted first light and the reflected light to provide a combined beam. The six surfaces of each of the triangular prism of the beam combiner is polished, thereby combining the lights without increasing etendue of the multi-colored illumination system.

Description

Etendu-efficient multi-light source coupler {ETENDUE EFFICIENT COMBINATION OF MULTIPLE LIGHT SOURCES}

The present invention relates to an improved system and methodology for providing multicolor illumination without increasing the etendue of the system.

This application claims priority to US Provisional Application No. 60 / 651,079, filed February 9, 2005. This application is partly filed in Serial No. 11 / 240,169, filed September 30, 2005. This is a continuing application of Serial No. 10 / 347,522 filed January 21, 2003 (currently US Pat. No. 6,982,830). This is a continuing application of serial number 09 / 814,970 filed March 23, 2001 (currently US Pat. No. 6,587,269). This claims priority to U.S. Provisional Application No. 60 / 227,312, filed August 24, 2000, and 60 / 246,683, filed November 8, 2000. All of which are referred to by reference throughout this specification.

Liquid crystal displays (hereinafter "LCDs") are known as devices used to control the transmission of polarization energy. The LCD may be transparent or opaque depending on the current applied to the LCD. Because of this function, projection systems often use arrays containing numerous LCDs to form image sources. In particular, the projection system inputs high intensity deflection light energy into an LCD array (also called an image indicator), and the LCD array selectively transmits a predetermined portion of the input light energy to project a desired image. Since a single LCD is relatively small, numerous LCDs can be packed together in an array, thereby forming an image indicator capable of producing high resolution images.

As described above, the projection system must first polarize the input light in the LCD. However, light energy from a light source, such as a light bulb, can have either p- or s-polarized light. LCD projectors typically use only half of the light energy from the light source because such input light rays in an LCD image indicator must be in one direction (ie, p-polarized or s-polarized). However, it is desirable for the projection system to maximize the brightness and intensity of the light output. Accordingly, there have been various methodologies for capturing useless polarization energy, converting the polarized light energy captured, and then redirecting the converted light energy toward the LD image display. This known method of polarization reconstruction involves the use of unwanted parts of the light beam (undesired polarization parts) to the half-wave plate, where the polarization is changed, and then recombined with the original polarized beam to generate an enlarged beam. Unfortunately, implementing this known methodology generally requires an intractable and complex system comprising an array of two-dimensional lens arrays and polarizing beam splitters. In addition, the known methodology can achieve the purpose of a projector to produce high intensity outputs at the expense of a lot of light energy.

Light guide systems have been used to separate white light rays into red (R), blue (B) and green (G) elements using light guides, prisms and beam splitters. If such a system is run in reverse, it is possible to combine a multicolor light source with a specific spectrum without increasing the etendue. Therefore, it is desirable to make a system that provides a multicolor illumination system without increasing etendue.

In response to this need, the present invention uses a waveguide system to perform a polarization recovery function in an LCD projection system. In particular, the waveguide polarization recovery system of the present invention polarizes the input light energy for use in the LCD image display and increases the illumination of the LCD image display by converting the polarization of the useless light energy. The compact polarization recovery waveguide system generally comprises the following optical elements, which are typically completed in a single unit: (1) an input waveguide for inputting unpolarized energy into the system, (2) an output waveguide for removing polarized energy from the system, and (3 A polarization beam splitter that receives light energy from an input waveguide, transmits light energy of a first polarization type and reflects light energy of a second polarization type, and (4) a wavelength plate converting polarization of transmitted or reflected light energy. It includes. In addition, polarization recovery systems generally include one or more mirrors disposed when it is necessary to direct the transmitted and / or reflected light energy to the output waveguide. The input and output waveguides can be shaped as needed for the projection system. For example, either or both of the input waveguide or output waveguide may be tapered up or down as needed to produce the desired image.

In a waveguide polarization recovery system, the input and output waveguides are configured to be in either substantially parallel or substantially perpendicular directions. In the shape where the input and output waveguides are substantially parallel, the output waveguide directly receives the light energy transmitted by the beam splitter. As such, light energy enters and exits the polarization recovery system in substantially the same direction. Alternatively, the input and output waveguides can be positioned substantially perpendicular to each other so that light energy can come from the polarization recovery system in a direction substantially perpendicular to each other in the direction of entry. In the shape of the vertical input and output waveguide, the mirror receives the light energy transmitted by the polarizing beam splitter and redirects this energy 90 degrees toward the output waveguide.

The polarization recovery waveguide system of the present invention combines the above listed optical elements into a single small unit. In one embodiment, the waveguide polarization recovery system further enhances total internal reflection to minimize loss of optical energy by the system by further including one or more "gaps" of optically transparent material positioned between the optical elements.

In the field of LED lighting, each LED typically emits a single color. N LEDs (typically N≥2) are used for multicolor use. Typically N LEDs, for example two LEDs, are placed side by side and combined with the same target. By varying the output of each LED, the desired color and brightness can be achieved. In order to combine color in this way, the etendue of a typical lighting system must increase with larger emission area. Thus, in one embodiment of the present invention, a light guide based system combines colors without increasing etendue.

According to one embodiment of the invention, the multicolor illumination system comprises a beam combiner. The beam combiner includes two triangular prisms and a filter that transmits the first light beam and reflects the second light beam, where each light beam has a different wavelength. The beam combiner combines the transmitted and reflected light beams to provide a combined beam. The surface of each of the triangular prisms is polished to combine the light rays without increasing the etendue of the multicolor illumination system.

According to one embodiment of the invention, a multicolor illumination system comprises n (n> 2) beam combiners that combine n + 1 rays and a low refractive index glue or air provided between each beam combiner. Gaps, where each ray has a different wavelength. Each beam combiner includes two triangular prisms and a filter that transmits the combined beam received from the previous beam combiner and reflects new rays previously transmitted or unreflected among the n + 1 rays, the surface of each triangular prism Is polished. The beam combiner combines the transmitted combined beam with the reflected new light beam to provide a new combined beam. The new combined beam is provided to the next beam combiner if the beam combiner is not the last beam combiner and output if the beam combiner is the last beam combiner. The low refractive index glue or air gap between each beam combiner allows the multicolor illumination system to combine all of the rays without increasing the etendue of the multicolor illumination system.

According to one embodiment of the present invention, a multicolor illumination system includes at least two LEDs, a light guide coupled to each LED, an X-cube, and a low refractive index glue or air gap. Two LEDs provide two rays of light with two different wavelengths. The X-cube combines the light rays received from each light guide coupled with the LEDs to provide an output beam. A low refractive index glue or air gap is provided between each light guide and the X-cube to couple the light rays without increasing the etendue of the multicolor illumination system.

According to one embodiment of the invention, the light engine comprises a multicolor illumination system as described above.

According to an embodiment of the present invention, a projection display system projects a light engine as described above, at least one light modulator panel that modulates light rays in accordance with a display signal, and modulated light rays on the display screen. It includes a projection lens.

 According to one embodiment of the invention, a method for multicolor illumination comprises combining a first light beam transmitted by a first filter and a second light beam reflected by the first filter with a first beam combiner to provide a combined beam. And combining the combined beam transmitted by the second filter and the third beam reflected by the second filter with a second beam combiner to provide an output beam, and to combine the beam without increasing etendue. Providing a low refractive index glue or air gap between the first and second beam combiners, wherein each light ray has a different wavelength.

According to one embodiment of the invention, a method for multicolor illumination comprises combining at least two rays of light having two different wavelengths received from corresponding two light guides into an X-cube, without increasing the etendue. Providing a low refractive index glue or air gap between each light guide and the X-cube to couple the light beams.

With reference to the following drawings will be described in detail with respect to the various advantages of the present invention. Like reference numerals denote like elements.

1-4 and 6-10 are schematic diagrams of a waveguide polarization reconstruction system in accordance with various embodiments of the present invention.

5 is a schematic diagram of a small projection apparatus including a polarization recovery system according to an embodiment of the present invention.

11 is a schematic view of a light guide tube including a 90 degree turn without air gaps or low refractive index glue.

Figure 12 is a schematic view of a light pipe including a 90 degree turn with an air gap or low refractive index glue in accordance with one embodiment of the present invention.

13A and 13B are schematic diagrams of a light guide-based multicolor system in accordance with one embodiment of the present invention.

14 is a schematic diagram of a light guide-based multicolor system according to an embodiment of the present invention.

Figure 15 is a schematic diagram of a light guide-based multicolor system including an X-cube according to one embodiment of the present invention.

Figure 16 is a schematic diagram of a light guide-based multicolor system including an X-cube in accordance with an embodiment of the present invention.

17 is a schematic diagram of a light guide-based multicolor system including an array of LEDs in accordance with an embodiment of the present invention.

18 is a schematic diagram of a projection system including the light guide system of the present invention.

19 is a graph showing peak or high intensity regions of blue, green and red light rays.

20 is a graph showing red rays formed by combining three different red rays having different high intensity regions.

According to embodiments of the present invention, the small waveguide polarization restoration system 10 as shown in FIGS. 1 to 4 and 6 to 10 includes an input waveguide 20 and a polarizing beam splitter (PBS). ), 30], the wave plate 40, and the output waveguide 50, and the wave plate may be a half wave plate or a quarter wave plate depending on the configuration. If it is necessary to induce the flow of light rays between the input and output waveguides 20, 50, the waveguide polarization recovery system 10 generally further comprises a mirror 60. In the following, several possible configurations for the waveguide polarization reconstruction system 10 will be described in general, and then the individual components will be discussed in detail.

1, 3 and 6 illustrate one shape of waveguide polarization recovery system 10 in which the output light energy is substantially parallel to the input light energy. In this embodiment, the input waveguide 20 directs non-polarized input light rays from the light source or LED light source to enter the PBS 30. The illustrated PBS 30 transmits p-polarized light, and the p-polarized portion of the input light energy maintains the same direction as the initial input direction while the s-polarized light is reflected perpendicular to the initial input direction. Half-wave plate 40 is arranged to receive the reflected s-polarized light and convert it to p-polarized light. The mirror 60 then changes the direction of the conversion energy from the half wave plate 40 to the initial input direction. Both the light energy transmitted from the PBS 30 and the light energy converted from the half wave plate 40 are recombined and mixed in the output waveguide. As a result, the output light energy is polarized with a uniform intensity profile. It can be readily seen that the opposite polarization output can be made by using PBS 30 which only transmits s-polarized light.

2, 4 and 7-8 illustrate one embodiment of a waveguide polarization recovery system 10 having another shape where the output light energy is perpendicular to the original input light energy. As in the embodiment of FIG. 1, the input waveguide 20 directs non-polarized input light rays to enter the PBS 30. As shown in FIG. In addition, the PBS 30 performs the same function of transmitting the p-polarized light, and the p-polarized portion of the input light energy is maintained in the same direction as the initial input direction while the s-polarized light is reflected perpendicularly to the initial input direction. do. However, in the shape of FIG. 2, one mirror 60 redirects the transmitted p-polarized portion of the input light energy to the output waveguide 50 by 90 degrees. In addition, the s-polarized light reflected from the PBS 30 propagates once through the quarter wave plate 40 ', and the second mirror 60 then quarters the reflected light energy for another pass. Reflected by the wave plate 40 '. The second pass is also in the direction of the output waveguide 50. Since the reflected s-polarized light passes twice through the quarter wave plate 40 ', as shown, the s-polarized light is p-polarized twice by a mirror and shifted half the wavelength. In addition, both p-polarized outputs will be mixed in the output waveguide to produce a uniform intensity output. The embodiment of Fig. 2 is comprised of only two optical regions, namely the input waveguide 20, the PBS 30, the first region formed through the combination of the quarter wave plate 40 'and the mirror 60, A second region formed through the combination of the input waveguide 50 and the second mirror 60 is required. Thus, the system is simple in design and relatively inexpensive. Also, as will be discussed in detail below, positioning the output light energy perpendicular to the original input light energy has the advantage that the projection system can be made smaller.

Unlike the above shape, in which the wave plate 40 deforms the light energy reflected by the PBS 30, the other shape of the waveguide polarization recovery system 10 deforms the wave plate to modify the light energy transmitted by the PBS 30. Locate it. For example, FIGS. 9 and 10 show the shape in which the half wave plate 40 is positioned to receive light energy transmitted by the PBS 30. In the shape of FIG. 9, the half wave plate 40 is located between the mirror 60 and the output waveguide 50 in an optical image. Half-wave plate 40 receives the transmitted light energy that is first changed in direction by the mirror (60). Similarly, in FIG. 10 a half wave plate 40 is positioned between the PBS 30 and the mirror 60. In this way, the light energy transmitted from the PBS 30 is first repolarized before being redirected toward the output waveguide 50. 9 and 10 are advantageous in that the input light energy passes through the polarization layer of the PBS 30 only once to reduce the optical energy loss of the system 10. In contrast, the shapes of FIGS. 2, 4 and 7-8 require some of the input light energy to pass through the PBS 30 twice.

The various shapes of the waveguide polarization recovery system 10 use the same components as detailed below.

In general, the input waveguide 20 is an integrator that collects light rays from a light source such as an arc lamp and mixes the light rays through a plurality of reflections to produce a more uniform intensity profile in the waveguide polarization recovery system 10. Similarly, output waveguide 50 is generally an integrator that focuses light rays from waveguide polarization recovery system 10 and mixes the light rays through a plurality of reflections to produce a more uniform intensity profile for illumination of an image indicator. The input waveguide 20 and the output waveguide 50 may be, for example, single core fiber melt fiber bundles, fiber bundles, hollow or hollow square or rectangular light guides or homogenizers, which may not be papered or tapered. . In an optical projection system, input waveguide 20 and output waveguide 50 generally have a rectangular cross section corresponding to the shape of an image indicator or finally projected image. The input waveguide 20 and the output waveguide 50 may be made of glass, quartz or plastic depending on the capacity requirements.

Either or both of input waveguide 20 and output waveguide 50 have tapered portions that increase or decrease as needed for the projection system. For example, FIGS. 3 and 4 and FIGS. 6 to 10 show waveguides in which the input cross section corresponds to the area of the light source, the output cross section is related to the dimensions of the LCD image indicator, and the input waveguide 20 'is a tapered rod. Embodiments of the polarization recovery system 10 are shown. If it is necessary to minimize stray light in the optical projection system, the final dimensions of the input waveguide 20 can be changed. Similarly, Figure 8 illustrates one embodiment of a waveguide polarization recovery system 10 in which the output waveguide 50 'is tapered as well. Depending on the performance parameters of the PBS 30, the wave plate 40, and the output requirements for the projection system, the polarization reconstruction may be performed at an aperture of a value not equal to the output aperture, so the output waveguide 50 'is tapered. It is advantageous to be. PBS 30 and waveplate 40 perform better at smaller numerical apertures, consequently converting the input optical energy into larger regions with smaller numerical apertures and then outputting the output waveguide 50 '. By converting the light energy back into a larger numerical aperture at, the advantageous increase in performance can be obtained. Overall tapering of the input waveguide 20 and output waveguide 50 may be selected to meet the overall performance requirements of the projection system, and similarly the input and output waveguides may be tapered in either direction.

Waveguide polarization recovery system 10 further includes a PBS 30. PBS 30 is a well known optical element that transmits one polarization energy while reflecting the other. In general, PBS 30 is a rectangular prism with a polarizing coating applied on a diagonal surface and made of an optically transparent material such as plastic or glass. Alternatively, the PBS 30 may include a material that selectively transmits the light energy according to the polarization of the light energy. However, it will be appreciated that many other designs and types of PBS exist and any of these other PBSs can be used in the waveguide polarization recovery system 10 of the present invention. PBS 30 is a well known and commercially useful item and will not be discussed further.

Another component of the waveguide polarization recovery system 10 is the wave plate 40. Wave plate 40 is an optically transparent element that converts the polarization of light energy passing through wave plate 40. Wave plate 40 generally changes the propagation of light rays on one axis, thereby changing the polarization. Wave plate 40 may be either half wavelength or quarter wavelength, depending on the needs of the particular configuration of waveguide polarization recovery system 10. Overall waveplate 40 is a well known and commercially available item and will not be discussed further.

Waveguide polarization recovery system 10 may further include one or more mirrors 60 when it is necessary to induce light energy through waveguide polarization recovery system 10. Mirrors are often known as metal coated glass surfaces or polished metal, but mirror 60 is not limited to this conventional definition for the purposes of the present invention. Instead, the mirror 60 can be thought of as any optical element capable of reflecting or redirecting light energy. For example, mirror 60 is a light guide that captures and redirects light energy using an angle of incidence, such as a prism or a light guide having a pivot that rotates 90 degrees (collectively referred to herein as a prism). Can be replaced. For example, FIGS. 9 and 10 illustrate a waveguide polarization recovery system 10 having a prism that directs or redirects the light energy transmitted by the PBS 30 toward the output waveguide 50. In systems with small apertures, total internal reflection can occur in the prism and consequently no coating is required.

In another preferred embodiment of the present invention, the waveguide polarization recovery system 10 shown in FIGS. 6-10 includes at least one optically transparent material, a low refractive index glue or " gap 70 " Collectively, the specification refers to a gap). The gap 70 may be a pocket of air left between the optical elements. The gap 70 may also be filled with low refractive index epoxy or other transparent material such that total internal reflection still occurs, but assembly of the components will be simple. For example, FIG. 6 shows a shape with a gap 70 between the input waveguide 20 and the PBS 30. This gap 70 is reflected by the diagonal PBS 30 because the total internal reflection from the interface between the PBS 30 and the gap 70 prevents light energy from being lost back to the input waveguide 20 instead. It ensures that the light energy is turned 90 degrees to face the quarter wave plate 40 '. The waveguide polarization recovery system 10 of FIG. 6 also has another gap 70 that promotes total internal reflection between other optical elements. Similarly, FIG. 7 shows a waveguide polarization recovery system 10 in which a gap 70 is added to a polarization recovery system having an output waveguide 50 configured perpendicularly to the tapered input waveguide 20 shown in FIG. 4. Doing. This gap 70 also increases efficiency by promoting total internal reflection between optical elements. As shown in Figures 6 and 7, the gap 70 increases the efficiency of the system while increasing the number of individual components, making the waveguide polarization recovery system 10 more complex.

9 and 10, the gap 70 also functions to enhance the performance of the prism 60 'that acts to direct optical energy toward the output waveguide 60' like a mirror. In particular, the light beams reflected from the hypotenuse of the prism 60 ′ back toward the PBS 30 collide with the interface of the gap 70 to be reflected therein and toward the output waveguide 50 therein. A gap 70 is needed between '). As such, the efficiency of the system can be improved by minimizing losses.

The performance of the gap 70 can be better by using an anti-reflection coating on both surfaces so that transmitted light suffers minimal loss.

5 shows a projector 100 using a waveguide polarization recovery system 10. Projector 100 includes a condensing system 110, which, as an example, includes two parabolic reflectors and a retro-reflector that increases output by reflecting light back from itself to light source 120. It includes. The arc light source 120 is positioned to focus on the first parabolic reflector and the tip of the input waveguide 20 is focused on the second parabolic reflector. This condensing system 110 is provided by way of example only and it can be appreciated that numerous other condensing systems are known and can be used. Likewise, the light source 120 may be an arc lamp such as xenon, metal lamp, HID or mercury lamp, and a filament lamp such as a halogen lamp if the system is modified to receive the non-opaque filament of the lamp. Can be.

In the projector 100 shown, the input waveguide 20 is a tapered light guide designed to match the input light collected from the condensing system 110 to fill the optical needs of the LCD image indicator 150. As described in FIG. 4, the light input of the input waveguide 20 is polarized by the PBS 30 and the other polarized light is restored by the quarter wave plate 40 '. The output waveguide 50 then directs the polarized optical energy towards the LCD image indicator 150. In such a case, the output light beam at the output waveguide 50 is then incident to the second PBS 130 having a direction that matches the polarization of the incident light beam to minimize losses. The color wheel 140 or other kind of color section system and the reflective LCD image indicator 150 produce an image projected by the projection lens 160 in a conventional manner. As shown in Fig. 5, the number of optical elements is minimized so that the projector cost is relatively inexpensive.

It will be appreciated that the waveguide polarization recovery system 10 may be used in other types of projection systems. For example, the projector may also use two or three image indicators 150 to form the projected image. Image display 150 may also be a reflective display using silicon liquid crystal (LCOS) technology or some other type of system that requires a polarization system.

Referring to Fig. 11, for example, there are shown light guide tubes 20 and 50 having a turning section that rotates 90 degrees but have no air gap or low refractive index glue and multiple light paths in the light guide tube. Light rays with a somewhat larger angle are lost, which reduces the efficiency of the light pipe system. In accordance with an embodiment of the present invention, light guide system 200 includes light guides 20 and 50 that include glue 70 of air gap or low refractive index, as shown in FIG. The light paths (a) and (c) lost in FIG. 11, for example, are recaptured by total internal reflection and collected by the output light pipe 50 of the light pipe system 200.

According to one embodiment of the present invention, as shown in FIG. 13A, the multicolor system 300 includes a coupler 310, 320, an air gap or low refractive index glue 70, and three light sources, red (R). ), Green (G) and blue (B) light sources. Each input light beam is directly or indirectly connected to the multicolor system 300 via a light guide or lens system 200 (not shown but as shown in FIG. 12). Each beam combiner comprises a filter and two prisms or beam splitters, preferably all sides polished triangular prisms. The first beam combiner 310 with filter A transmits the red light beam R and reflects the green light beam G. It can be seen that filter A is controlled, adjusted or selected to transmit the red light beam R and reflect the green light beam G. The red ray R from the input is transmitted by the first coupler 310 and the green ray G from the other side of the first coupler 310 is reflected. The reflected green rays G come together out of the same plane of the combiner 310 in combination with the transmitted red rays R. The combined red / green rays R, G then enter a second combiner 320 having a filter B that transmits the red and green rays R, G and reflects the blue rays B. FIG. It can be seen that filter B is controlled, adjusted or selected to transmit red and green rays R, G and reflect blue rays B. FIG. As a result, the red / green light continues to pass through the second combiner 320 and the blue light beam B from the blue input is reflected by the second combiner 320. Reflected blue light rays B combine with transmitted red and green light rays R, G, and combined light rays R, G, B come out of multicolor system 300 together. It can be seen that the output intensity and color are controlled according to the amount of light of each color input to the multicolor system 300. In addition, the placement of the light sources is arbitrary and depends on the use of the multicolor system 300. That is, the blue light beam B may be input instead of the green light beam G to the first beam combiner 310 having the filter A adjusted to reflect the blue light beam B instead of the green light beam G. The output beam of the multicolor system 300 of the present invention occupies the same cross section as the individual input beams, thus maintaining the same etendue as a single light source. Efficient coupling of light rays can be obtained by providing an air gap or low refractive index glue 70 between various optical elements such as beam combiners 310 and 320. According to aspects of the present invention, the combined output beam of the multicolor system 300 of the present invention may be used as an optical engine for a fiber optic lighting device or a projection display, for example for a projection display system.

According to one embodiment of the invention, as shown in FIG. 13B, the multicolor system 300 includes a beam combiner 310 and two light sources, a red (R) and a green (G) light source. Each ray input is coupled directly or indirectly to the multicolor system 300 via a light guide or lens system 200 (not shown but as shown in FIG. 12). Each beam combiner includes a filter and two prisms or beam splitters, preferably all sides polished triangular prisms. The first beam combiner 310 with filter A transmits the red light beam R and reflects the green light beam G. It can be seen that filter A is controlled, adjusted or selected to transmit the red light beam R and reflect the green light beam G. The red ray R from the input is transmitted by the first coupler 310 and the green ray G from the other side of the first coupler 310 is reflected. The reflected green rays G come together out of the same plane of the combiner 310 in combination with the transmitted red rays R. It can be seen that the output intensity and color are controlled according to the amount of light of each color input to the multicolor system 300. In addition, the placement of the light sources is arbitrary and depends on the use of the multicolor system 300. That is, the blue light beam B may be input instead of the green light beam G to the first beam combiner 310 having the filter A adjusted to reflect the blue light beam B instead of the green light beam G. The output beam of the multicolor system 300 of the present invention occupies the same cross section as the individual input beams, thus maintaining the same etendue as a single light source. Efficient combination of light rays can be obtained by reflecting polished surfaces of triangular prisms. According to aspects of the present invention, the combined output beam of the multicolor system 300 of the present invention may be used as an optical engine for a fiber optic lighting device or a projection display, for example for a projection display system.

According to one embodiment of the invention, each of the input light sources R, G, B in FIGS. 13A and 13B is an LED light source coupled with a straight or tapered light guide 330 as shown in FIG. Although an upward tapered light guide 330 is shown in FIG. 14, it can be seen that the downward tapered light guide 330 can be used as well. As shown in Fig. 17, it can be seen that the light source may be a plurality of LED light sources or an array I ₁ -In (n ≧ 2) of LED light sources, each providing light rays having different colors or wavelengths. Alternatively, the light source I ₀ may be provided as an input to the beam combiner BC ₁ for transmitting light from the light source I ₀ to the next beam combiner BC _2. Rays or light energy from each of the light source I _j is reflected by the corresponding beam combiner BC _j comprises a filter for F _j and wavelength matching of the light from the light source I _j. Reflected light I _j is transmitted light I ₀ . Combine with I _{j - 1,} and combine beam I ₀ . I _j then enters the next beam combiner BC _{j +1} . Finally, the combined rays I ₀ ... I _n exits beam combiner BC _n and enters straight, upward tapered or downward tapered output light pipe 430. Although not shown, each light source may be coupled in a straight, upward tapered or downward tapered light pipe 330 as shown in FIG.

If improved color is desired as a particular use of the present invention, a plurality of LEDs can be used that generate a variety of colors to cover a wide area with a color coordinate space. In projection display systems, six-color systems have been known to provide sharper and sufficient colors. According to one embodiment of the present invention, the n-color projection display system is provided with n different LED light sources I ₁ ,... Which provide n different color light rays or light rays with n different wavelengths as shown in FIG. 17. , I _n ). Filters F _j is an LED light source is controlled, adjusted or selected to match the wavelength of λ _j I _j to reflect only light having a wavelength λ _j.

According to one exemplary embodiment of the present invention, the brightness of the output light beam can be controlled and increased with the appropriate choice of filter or light source to provide clearer and more intense colors. For example, each filter F _j can be controlled, adjusted or selected to filter out the low intensity portion of the light or light energy from the corresponding light source or LED light source, thereby propagating only the high intensity portion of the light beam to produce a brighter output beam. Can be generated.

According to one exemplary embodiment of the present invention, as shown in Figure 20, a plurality of LED light sources can be used to enhance a single color, for example red. In general, as shown in Fig. 19, each ray has a high intensity region, for example, a red ray has a high intensity region λ _R , and a blue ray has a high intensity region λ _B. For example, three different red rays R1, R2 and R3 having high intensity regions λ _R1 , λ _R2 and λ _R3 , respectively, are input to the X-cube 410 or beam combiner 310, 320, BC _j to provide a single high intensity. Let's combine to form a red beam of light. The corresponding filters F _R1 , F _R2 and F _R3 each filter out the low intensity region of the red rays R1, R2 and R3.

According to one embodiment of the present invention, as shown in Figures 15 and 16, the multicolor system 400 uses an X-cube color combiner (i) to combine the beams without increasing the etendue of the multicolor system 400. 410) (or X-cube 410). Each light source (FIG. 16) or LED light source (FIG. 15) is coupled to a straight, upward tapered or downward tapered light pipe 420. The red ray R from the red light source or red LED enters the X-cube 410 through the straight, upward tapered or downward tapered light guide 420 to the first input surface of the X-cube 410. The red ray R is transmitted by the X-cube 410 and exits the output surface of the X-cube 410 and exits to the straight, upward tapered or downward tapered output light guide 430. The green light beam G from the green light source or green LED light source enters the X-cube 410 through the straight, upward tapered or downward tapered light guide 420 to the second input surface of the X-cube 410. . X-cube 410 reflects green light rays (G). The reflected green light beam G, coupled with the transmitted red light beam R, comes out of the same output surface of the X-cube 410 and exits to a straight, upward tapered or downward tapered output light guide 430. The blue light beam B from the blue light source or blue LED light source enters the X-cube 410 through the straight, upward tapered or downward tapered light guide 420 into the third input face of the X-cube 410. . X-cube 410 reflects a blue light ray (B). The reflected blue light beam B, combined with the transmitted red light beam R and the reflected green light beam G, comes out of the same output surface of the X-cube 410 to produce a straight, upward tapered or downward tapered output light guide. Exit to tube 430. The light guides 420, 430 may be, for example, single core fiber melt fiber optic bundles, fiber bundles, hollow or hollow square or rectangular light guides or homogenizers, which may not be papered or tapered upwards or downwards. It can be seen that the output intensity and color are controlled by the amount of light rays of each color input to the multicolor system 400 by the corresponding light source or LED light source. It can also be seen that the placement of the light sources is arbitrary and depends on the use of the multicolor system 400. That is, the red light ray R may be input to the second input surface of the X-cube 410 instead of the green light G that is input to the second input surface of the X-cube 410. The output beam of the multicolor system 400 of the present invention occupies the same cross section as the individual input beams, thus maintaining the same etendue as a single light source. Efficient coupling of light rays can be obtained by providing an air gap or low refractive index glue 70 between the X-cube 410 and various optical elements such as straight, upward tapered or downward tapered light guides 420 and 430. have. According to aspects of the present invention, the combined output beam of the multicolor system 400 of the present invention may be used as an optical engine for a fiber optic lighting device or a projection display, for example a projection display system.

According to one aspect of the present invention, the efficient coupling of the light beams results in an air gap or low refractive index between various optical elements such as light guides 20, 50, 330, prisms and beam combiners 310, 320, BC ₁ -BC _n . It can be obtained by providing a glue 70 of. This air gap or low refractive index glue 70 provides total internal reflection to reflect the light rays back to the multicolor system 300, thereby minimizing or eliminating the loss of light or light energy.

It will be readily apparent to one skilled in the art that other configurations may be made that follow the same concept as the present invention and differ in the position of the light source and the filter set. The order of the two or n colors can be changed. In addition, the entry position of the color LED may be changed.

According to one embodiment of the invention, the method for multicolor illumination comprises a first beam combiner (1) and a second beam (G) transmitted by the first filter A and a second beam (G) reflected by the first filter A. 310 to provide a combined beam, and to combine the combined beam transmitted by the second filter B and the third light beam B reflected by the second filter B with a second beam combiner 320 Providing an output beam and providing a low refractive index glue or air gap between the beam combiners 310, 320 to couple the light beams without increasing the etendue, wherein each light beam has a different wavelength. Has

According to one embodiment of the invention, a method for multicolor illumination comprises combining at least two rays of light having two different wavelengths received from two corresponding light guides 330 into an X-cube 410; Providing a low refractive index glue or air gap between each light pipe 330 and the X-cube 410 to couple the light rays without increasing the etendue.

Referring back to Figure 17, in accordance with one embodiment of the present invention, a schematic diagram of a light beam projection system including a light guide based multicolor system of the present invention is shown. The output from the LED light source 510, for example, any of the multicolor systems described herein, is generated by a projection engine 520 (eg, digital light processing) that generates an image projected by the projection lens 530 in a conventional manner. (DLP), silicon liquid crystals (LCOS), or high temperature polysilicon (HTPs). According to one aspect of the invention, the projection engine 520 includes at least one light modulation panel that modulates light rays in accordance with a display signal, and the projection lens 530 projects the modulated light rays on the display screen.

It is also possible to implement the system generally by using round prisms or filters for round optical fibers.

Solid tapered light guides 330, 420, 430 are shown in FIGS. 14, 15, and 17, but include a compound parabolic concentrator (CPC), a lens, a hollow or hollow square CPC or light guide. Other combination configurations and any other video or non-image system may be used. According to one embodiment of the invention, the tapered light guide has a lens output surface. In addition, according to an embodiment of the present invention, the input portion of the light pipe has a shape to increase the coupling efficiency from the LED light source.

Although the present invention has been described with particular reference to the illustrated embodiments, it will be appreciated that various repetitions, modifications, and adaptations may be made based on the disclosure and may be envisioned within the technical scope of the present invention. The appended claims may be construed to include the embodiments described above, various alternatives, and all equivalents.

Claims (26)

Multicolor lighting system with beam combiner, The beam combiner comprises two triangular prisms and a filter that transmits the first light beam and reflects the second light beam, Each ray has a different wavelength, The beam combiner is operable to combine the first transmitted light beam and the reflected light beam to provide a combined beam, The surface of each of the two triangular prisms is polished to combine the light rays without increasing the etendue of the multicolored illumination system. 2. The apparatus of claim 1, wherein n beam combiners that combine n + 1 rays (n is greater than 2) are provided between each beam combiner to increase the etendue of the multicolor illumination system. Further comprising a low refractive index glue or air gap that combines all, Each said ray has a different wavelength, Each beam combiner comprises two triangular prisms and a filter that transmits the combined beam received from the previous beam combiner and reflects new rays previously transmitted or unreflected among the n + 1 rays; The surface of each of the triangular prisms is polished, and each beam combiner combines the transmitted combining beam with the reflected new light beam, so that if each beam combiner is not the last beam combiner, a new combining beam is added to the next beam combiner. Or output the new combined beam if each beam combiner is the last beam combiner. 3. The multicolor illumination system of claim 2, further comprising n light sources for generating n light rays each having a different wavelength. 4. The multicolor lighting system of claim 3, wherein each light source is an LED or an array of LEDs. The multicolor illumination system of claim 1, further comprising an output light guide positioned to receive a substantial portion of the combined beam. 6. The multicolor illumination system of claim 5, wherein the output light guide is one of a straight light guide, an upward tapered light guide, or a downward tapered light guide. 6. The multicolor illumination system of claim 5, further comprising a low refractive index glue or air gap between the output light guide and the beam combiner. 5. The multicolor lighting system of claim 4, further comprising a light guide coupled with each LED or array of LEDs. 10. The multicolor illumination system of claim 8, wherein the light guide is one of a straight light guide, an upward tapered light guide or a downward tapered light guide. 2. The apparatus of claim 1, wherein n beam combiners combining n beams (n is greater than 2) are provided between each beam combiner to reduce all of the beams without increasing the etendue of the multicolor illumination system. Further comprising a low refractive index glue or air gap to bond, Each said ray has a different wavelength, Each beam combiner comprises two triangular prisms and a filter that transmits the combined beam received from a previous beam combiner and reflects new rays previously transmitted or unreflected among the n rays, the two triangular prisms Each surface is polished and each beam combiner combines the transmitted combined beam with the reflected new light beam to provide a new combined beam to the next beam combiner if the respective beam combiner is not the last beam combiner. Or output the new combined beam when each beam combiner is the last beam combiner, wherein each ray has a different wavelength. An optical engine for a projection display system comprising the multicolor illumination system of claim 2. The light engine of claim 11, wherein the light engine is one of digital light processing (DLP), silicon liquid crystal (LCOS), or high temperature polysilicon (HTP). 12. A projection display system comprising a light engine for a projection display system of claim 11, at least one light modulation panel for modulating light rays in accordance with a display signal, and a projection lens for projecting the modulated light rays on a display screen. An optical engine for a projection display system comprising the multicolor illumination system of claim 1. Is a multicolor lighting system, At least two LEDs or arrays of LEDs that provide two light beams having two different wavelengths, A light guide coupled with each LED or array of LEDs, An X-cube that combines the light rays received from each light guide coupled with the LED to provide an output beam, A low refractive index glue or air gap between the respective light guide and the X-cube that couples the light beams without increasing the etendue of the multicolored illumination system. 16. The multicolor illumination system of claim 15, further comprising n LEDs or arrays of LEDs providing n light rays (n is greater than 2), wherein each light ray has a different wavelength. 16. The multicolor lighting system of claim 15, further comprising an output light pipe positioned to receive a substantial portion of the output beam. 18. The multicolor illumination system of claim 17, wherein the output light guide is one of a straight light guide, an upward tapered light guide, or a downward tapered light guide. 19. The multicolor illumination system of claim 18, further comprising a low refractive index glue or air gap between the output light guide and the X-cube. 16. The multicolor illumination system of claim 15, wherein each light guide is one of a straight light guide, an upward tapered light guide, or a downward tapered light guide. An optical engine for a projection display system comprising the multicolor illumination system of claim 16. The light engine of claim 21, wherein the light engine is one of digital light processing (DLP), silicon liquid crystal (LCOS), or high temperature polysilicon (HTP). 23. A projection display system comprising a light engine for a projection display system of claim 22, at least one light modulation panel for modulating light rays in accordance with a display signal, and a projection lens for projecting the modulated light rays on a display screen. A light engine for a projection display system comprising the multicolor illumination system of claim 15. Combining the first light beam transmitted by the first filter and the second light beam reflected by the first filter by a first beam combiner to provide a combined beam, Combining the combined beam transmitted by the second filter and the third beam reflected by the second filter by a second beam combiner to provide an output beam; Providing a low refractive index glue or air gap between the first and second beam combiners to couple the light rays without increasing etendue, Wherein each light beam has a different wavelength. Combining by X-cube at least two light rays having two different wavelengths received from corresponding two light guides, Providing a low refractive index glue or air gap between each light guide and the X-cube that combines the light beam without increasing etendue.

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