Abstract:
An illumination system suited for projection display applications is disclosed. The illumination system according to this invention includes a red light-emitting diode (R-LED) light source array, a green light-emitting diode (G-LED) light source array, and a blue light-emitting diode (B-LED) light source array. In one preferred embodiment, the R/G/B-LED light source arrays are coupled to different sides of an x-cube component. Light beams emanated from respective light source arrays are combined by the x-cube component, thereby generating a white-light source for display purposes.

Description:
BACKGROUND OF INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to an illumination system, and more particularly, to an illumination system for optical projection apparatuses.  
         [0003]     2. Description of the Prior Art  
         [0004]     Projectors are devices utilizing optical projections to cast images onto large size screens. According to different light valves used, projectors can be roughly classified into categories including Cathode Ray Tube (CRT) projectors, Liquid Crystal Display (LCD) projectors, Digital Light Processing (DLP) projectors, and Liquid Crystal on Silicon (LCoS) projectors. The LCD projectors operate by utilizing light beams to penetrate LCD panels, hence they are also referred to as penetrating projectors. LCoS and DLP projectors on the other hand operate by light reflection principles to produce images, and are hence also referred to as reflective projectors.  
         [0005]     The fundamental principle of the LCoS projectors is essentially similar to that of the LCD projectors, except the light signals controlling the projective image to the frame of the LCoS projectors are adjusted by the LCoS panel. The LCoS panel is formed by utilizing a silicon chip as an electrical circuit substrate and a reflective layer, coating the chip with a liquid crystal layer, and finally packing with a glass panel. In contrast to LCD projectors that utilize a light source to penetrate the LCD for performing various adjustments, hence also referred to as penetrating projectors, the LCoS projectors are reflective projectors that utilize a reflective architecture, in which the light emitted from the light source is not penetrated through the LCoS panel.  
         [0006]     Despite the fact that the light sources utilized by most projectors on the market today are high pressure mercury lamps having the advantage of high brightness, the cost of such lamps are considerably more expensive, much larger in size, and have a much shorter life expectancy. Since the mercury lamps often need to be replaced within a short period of time, the industry is looking for a way to develop a much more suitable solution for replacing the light source of projectors.  
       SUMMARY OF INVENTION  
       [0007]     It is therefore an objective of the present invention to provide an illumination system for optical projection apparatuses for improving the illumination system of the prior art.  
         [0008]     According to the present inventions, an illumination system for projection apparatuses comprises a red light-emitting diode (R-LED) light source array, a green light-emitting diode (G-LED) light source array, and a blue light-emitting diode (B-LED) source array, in which red, green, and blue light beams are emanated from the R/G/B-LED light source arrays via a light combination device for generating a white-light source. Each R/G/B-LED light source array includes a substrate and a plurality of light-emitting diodes fixed on the substrate and the light-emitting diodes are positioned toward the light combination device. The light combination device can be a horizontal crossed prism or an x-cube light combination prism component. Alternatively, the light combination device can also be a horizontal crossed reflector or an x-plate light combination component.  
         [0009]     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]      FIG. 1  is a perspective diagram showing the illumination system for projection apparatuses according to the first embodiment of the present invention.  
         [0011]      FIG. 2  is a three-dimensional diagram showing the light combination device according to the first embodiment of the present invention.  
         [0012]      FIG. 3  is a perspective diagram showing the illumination system for projection apparatuses according to the second embodiment of the present invention.  
         [0013]      FIG. 4  is a three-dimensional diagram showing the light combination device according to the second embodiment of the present invention.  
         [0014]      FIG. 5  is a perspective diagram showing the illumination system for projection apparatuses according to the third embodiment of the present invention.  
         [0015]      FIG. 6  is a three-dimensional diagram showing the light combination device according to the third embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0016]     Please refer to  FIG. 1 .  FIG. 1  is a perspective diagram showing the illumination system  10  for projection apparatuses according to the first embodiment of the present invention. According to the first embodiment of the present invention, the illumination system for projection apparatuses comprises a red light-emitting diode (R-LED) light source array  12 , a green light-emitting diode (G-LED) light source array  14 , and a blue light-emitting diode (B-LED) source array  16 , in which red, green, and blue light beams are emanated from the R/G/B-LED light source arrays  12 ,  14 ,  16  and combined via a light combination device  20  for generating a white-light source. As shown in  FIG. 1 , the R-LED light source array  12  includes a curved substrate  121  and a plurality of R-LEDs  122  fixed on the curved substrate  121 . The G-LED light source array  14  includes a curved substrate  141  and a plurality of G-LEDs  142  fixed on the curved substrate  141 . The B-LED light source array  16  includes a curved substrate  161  and a plurality of B-LEDs  162  fixed on the curved substrate  161 . All of the light-emitting diodes listed are positioned toward the light combination device.  
         [0017]     According to the first embodiment of the present invention, the curved substrates  121 ,  141 , and  161  are mirror substrates with equal curvatures positioned in a corresponding manner around the light combination device  20 , where the maximum light intensity axial of the R-LED  122  is roughly pointed toward the center of the light combination device  20 . It should be noted that the substrates  121 ,  141 , and  161  of the R/G/B-LED light source arrays  12 ,  14 ,  16  of the illumination system  10  can also be flat substrates instead of curved substrates. Alternatively, a similar effect can be achieved by changing the arrangement of the light-emitting diodes  122  such as tilting the diodes at an angle, thereby causing the maximum light intensity axial to point toward the center of the light combination device  20 . In addition, the curved substrates  121 ,  141 , and  161  should also be comprised of heat radiating materials.  
         [0018]     According to the first embodiment of the present invention, the light combination device  20  can be a traditional horizontal crossed prism or a so-called “X-Cube” light combination prism component. Please refer to  FIG. 2 .  FIG. 2  is a three-dimensional diagram showing the light combination device  20  according to the first embodiment of the present invention. By using the X-Cube light combination prism component as an example, the X-Cube light combination prism component includes a light converting surface  211  that enables the reflection of blue light beams and the penetration of green light beams and a light converting surface  212  that enables the reflection of red light beams and the penetration of green light beams. By combining the red, green, and blue light beams emanated from the R/G/B-LED light source arrays  12 ,  14 ,  16  via the light combination device  20 , a white light beam  30  is generated and transmitted back to a polarity conversion and energy recycling system  50 , which can be a combination of lens array and PCS or a recyclable light pipe device. After exiting from the polarity conversion and energy recycling system  50 , the polarized beams are transmitted through the lens group and an optical engine  60  and are finally projected to a screen by the projection lens (not shown).  
         [0019]     Please refer to  FIG. 3  and  FIG. 4 .  FIG. 3  is a perspective diagram showing the illumination system  10   a  for projection apparatuses and  FIG. 4  is a three-dimensional diagram showing the light combination device  20   a.  According to the second embodiment of the present invention, red, green, and blue light beams are emanated from the R/G/B-LED light source arrays  12 ,  14 ,  16  and combined to form a white-light source by the light combination device  20   a.  As shown in  FIG. 3 , the R-LED light source array  12  includes a curved substrate  121  and a plurality of R-LEDs  122  fixed on the curved substrate  121 . The G-LED light source array  14  includes a curved substrate  141  and a plurality of G-LEDs  142  fixed on the curved substrate  141 . The B-LED light source array  16  includes a curved substrate  161  and a plurality of B-LEDs  162  fixed on the curved substrate  161 .  
         [0020]     According to the second embodiment of the present invention, the curved substrates  121 ,  141 , and  161  are mirror substrates with equal curvatures positioned in a corresponding manner around the light combination device  20   a,  where the maximum light intensity axial of the R-LED  122  is roughly pointed toward the center of the light combination device  20   a.  It should be noted that the substrates  121 ,  141 , and  161  of the R/G/B-LED light source arrays  12 ,  14 ,  16  of illumination system  10   a  can also be flat substrates instead of curved substrates. Alternatively, a similar effect can be achieved by changing the arrangement of the light-emitting diodes  122  such as tilting the diodes at an angle, thereby causing the maximum light intensity axial to point toward the center of the light combination device  20   a.    
         [0021]     As shown in  FIG. 4 , the light combination device  20   a  can be a traditional horizontal crossed prism or a so-called “X-Plate” light combination prism component. By using the X-Plate light combination prism component as an example, the X-Plate light combination prism component includes a light converting surface  211  that enables the reflection of blue light beams and the penetration of green light beams and a light converting surface  212  that enables the reflection of red light beams and the penetration of green light beams. By combining the red, green, and blue light beams emanated from the R/G/B-LED light source arrays  12 ,  14 ,  16  via the light combination device  20   a,  a white light beam  30  is generated and transmitted back to a polarity conversion and energy recycling system  50 , which can be a combination of a lens array and PCS or a recyclable light pipe device. After exiting from the polarity conversion and energy recycling system  50 , the polarized beams are transmitted through the lens group and an optical engine  60  and are finally projected to a screen by the projection lens (not shown).  
         [0022]     Please refer to  FIG. 5  and  FIG. 6 .  FIG. 5  is a perspective diagram showing the illumination system  10   b  for projection apparatuses and  FIG. 6  is a three-dimensional diagram showing the light combination device  20   b.  According to the third embodiment of the present invention, red, green, and blue light beams are emanated from the R/G/B-LED light source arrays  12 ,  14 ,  16  and combined to form a white-light source by the light combination device  20   b.  As shown in  FIG. 5 , the R-LED light source array  12  includes a curved substrate  121  and a plurality of R-LEDs  122  fixed on the curved substrate  121 . The G-LED light source array  14  includes a curved substrate  141  and a plurality of G-LEDs  142  fixed on the curved substrate  141 . The B-LED light source array  16  includes a curved substrate  161  and a plurality of B-LEDs  162  fixed on the curved substrate  161 .  
         [0023]     According to the third embodiment of the present invention, the curved substrates  121 ,  141 , and  161  are mirror substrates with equal curvatures positioned in a corresponding manner around the light combination device  20   b,  where the maximum light intensity axial of the R-LED  122  is roughly pointed toward the center of the light combination device  20   b.  It should be noted that the substrates  121 ,  141 , and  161  of the R/G/B-LED light source arrays  12 ,  14 ,  16  of illumination system  10   b  can also be flat substrates instead of curved substrates. Alternatively, a similar effect can be achieved by changing the arrangement of the light-emitting diodes  122  such as tilting the diodes at an angle, thereby causing the maximum light intensity axial to point toward the center of the light combination device  20   b.    
         [0024]     As shown in  FIG. 6 , the light combination device  20   a  can be a traditional horizontal crossed prism or a so-called “X-Plate” light combination prism component. By using the X-Plate light combination prism component as an example, the X-Plate light combination prism component includes a light converting surface  211  that enables the reflection of blue light beams and the penetration of green light beams and a light converting surface  212  that enables the reflection of red light beams and the penetration of green light beams. By combining the red, green, and blue light beams emanated from the R/G/B-LED light source arrays  12 ,  14 ,  16  via the light combination device  20   a,  a white light beam  30  is generated and transmitted back to a polarity conversion and energy recycling system  50 , which can be a combination of lens array and PCS or a recyclable light pipe device. After exiting from the polarity conversion and energy recycling system  50 , the polarized beams are transmitted through the lens group and an optical engine  60  and finally projected to a screen by the projection lens (not shown).  
         [0025]     According to the present invention, the light source can be applied to illumination systems with various kinds of light valves. In addition, the corresponding location of the R-LED source array, the G-LED source array, and the B-LED source array can be adjusted according to the reflective property of the light combination device, which is unattainable by the prior art. Also, the substrate surface regarding to the arrangements of the LED source array can also be selected from different curving surfaces such as parabolic, elliptical, spherical, or non-spherical according to the dispersion angle of the single LED light source.  
         [0026]     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.