Abstract:
A SLM includes a pixel array. The pixel array contains a plurality of quadrilateral pixels with the same size, wherein an interior angle of each of the quadrilateral pixels is an acute angle. Each of the quadrilateral pixels further contains a first subpixel, a second subpixel, and a third subpixel.

Description:
BACKGROUND OF INVENTION 
   1. Field of the Invention 
   The invention relates to a spatial light modulator (SLM) and a method for color management thereof, and more particularly, to a SLM and a method for color management thereof through adjusting shapes and arrangements of pixels and subpixels. 
   2. Description of the Prior Art 
   SLM is an application of the photoelectric system, which has the advantages of adjusting wavelengths, phases, and polarization of lights, and can be applied to optical signal treatments, amplifying images, and transferring incoherent lights into coherent lights. Accordingly, with the arrival of the digital age, the use of SLMs has become more and more popular in every field. A liquid crystal on silicon (LCOS) display is one kind of SLM that combines the technologies of semiconductors and LCDs. The LCOS display can provide images with high resolution and high lightness. In addition, the LCOS display has a structure simpler than other kinds of SLMs, so that the LCOS display has a potential of low cost and has become popular in the digital projection field. 
   The main structure of an LCOS display includes a light source module, a LCOS panel, and a color separation and combination optical system. Generally speaking, the LCOS display can be divided into three-panel LCOS displays and single-panel LCOS displays according to the type of optical engine. The three-panel type optical engine separates lights generated from light source into red, blue, and green lights through plurality of prisms, projects those lights into three separated LCOS panels respectively, and combines those three lights from LCOS panels to form colored images. The single-panel type optical engine utilizes a color wheel to form red, blue, and green lights sequentially from white lights, and synchronizes the three kinds of lights with single-colored images, the red, blue, and green images, of the LCOS panel formed by driving programs so as to produce color-separated images sequentially. Since human eyes have the persistence of vision, people can see colored images from the projected images. 
   Please refer to  FIG. 1 , which is a schematic diagram of a portion of an LCOS panel  10  according to the prior art. The LCOS panel  10  comprises pluralities of rectangular pixels  12  arranged in a pixel array. When the pixel transistors (not shown) positioned on the substrate of the LCOS panel  10  are opened, the corresponding liquid crystal molecules twist according to driving signals so that light can pass through the liquid crystal materials to create images. Accordingly, a conventional LCOS panel only reflects lights with a single color depending on the driving signals of pixels but cannot provide the functionality of managing colors. 
   On the other hand, in a conventional SLM, the pixels of the pixel array are all rectangular. Please refer to  FIG. 2 , which is an enlarged view of the pixel shown in  FIG. 1 . The conventional pixel  40  has a rectangular shape. Therefore, when the red, blue, and green subpixels are positioned in the conventional pixel  40 , the conventional subpixels have to be designed as rectangular shapes and all have the same size, as the subpixels  42 ,  44 ,  46  show in  FIG. 2 . Taking the subpixel  42  as an example, a dotted line connecting the four vertexes of the rectangular subpixel  42  approximately forms an ellipse. Consequently, the areas of the rectangular subpixels  42 ,  44 ,  46  are not circular, and therefore the conventional subpixels  42 ,  44 ,  46  cannot provide either preferable images or the functionality of color management according to the color and image requirements of manufacturers. 
   SUMMARY OF INVENTION 
   It is therefore a primary objective of the claimed invention to provide an SLM and a method for color management through changing the shapes of pixels and positioning subpixels with different shapes to solve the above-mentioned problem. 
   According to the claimed invention, the present invention SLM comprises a plurality of quadrilateral pixels arranged in a pixel array, wherein each of the quadrilateral pixels has the same size and has an interior angle that is an acute angle. Each of the quadrilateral pixels further comprises a first subpixel, a second subpixel, and a third subpixel. 
   According to the claimed invention, the present invention further provides a method for color management of a SLM. First, a plurality of pixels with the same sizes and shapes are positioned in the SLM, which are arranged in a pixel array, and a first subpixel, a second subpixel, and a third subpixel are positioned in each of the pixels, wherein the first, the second, and the third subpixels represent one of the optical fundamental colors. Then, the shapes of the pixels are adjusted according to a color temperature requirement of the SLM provided that the adjusted shapes of the pixels are all the same, and the shapes and areas of the first, the second, and the third subpixels are then adjusted according to the color temperature requirement of the SLM. After that, a plurality of color filters are positioned in the SLM corresponding to the first, the second, and the third subpixels in the SLM, so that each of the first, the second, and the third subpixels displays one of the optical fundamental colors when the SLM is operating. 
   It is an advantage of the claimed invention that the pixels of the SLM have a parallelogram shape or a trapezoid shape, so that each of the subpixels positioned in the pixels can be designed to have a shape similar to a circle so that the SLM can produce display images with preferable colors. Furthermore, the claimed invention provides a method through designing the red, blue, and green subpixels with different shapes and areas to reach the goal of color management of the SLM. 
   These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a schematic diagram of a portion of an LCOS panel according to the prior art. 
       FIG. 2  is an enlarged view of the pixel shown in  FIG. 1 . 
       FIG. 3  is a schematic diagram of a portion of an LCOS panel according to the present invention. 
       FIGS. 4–5  are enlarged views of the pixel shown in  FIG. 3 . 
       FIG. 6  is a section view of the pixel shown in  FIG. 4 . 
       FIG. 7  is an enlarged view of a rectangular pixel. 
       FIG. 8  is an enlarged view of pixels of an SLM of another embodiment according to the present invention. 
       FIG. 9  is a flow chart of a method for color management of an SLM according to the present invention. 
   

   DETAILED DESCRIPTION 
   Please refer to  FIGS. 3–6 .  FIG. 3  is a schematic diagram of a portion of a display panel  20  according to the present invention.  FIGS. 4–5  are enlarged views of one of the pixels shown  22  in  FIG. 3 .  FIG. 6  is a section view of the pixel  22  shown in  FIG. 4 . In this embodiment, the SLM is an LCOS display. As shown in  FIG. 3 , the display panel  20  comprises a plurality of pixels  22  with the same sizes and shapes arranged in a pixel array, and the pixels  22  have a parallelogram shape. 
   Each of the pixels  22  of the present invention SLM comprises three subpixels  24 ,  26 ,  28  representing one of the optical fundamental colors, red, blue, and green. The display panel  20  further comprises a plurality of red, blue, and green color filters  24   a ,  26   a ,  28   a  corresponding to the subpixels  24 ,  26 ,  28  so that each of the subpixels  24 ,  26 ,  28  display one of the optical fundamental colors simultaneously when the present invention SLM is operating. Accordingly, the present invention SLM can display colored images through a single display panel without color wheels or light separation and combination systems. Therefore, the manufacturing cost and SLM volume can be reduced. 
   Referring to  FIG. 6 , the present invention display panel  20  further comprises a semiconductor substrate  34  with pluralities of MOS transistors and pixel electrodes (not shown) thereon, a glass substrate  32  positioned in parallel with and opposite to the semiconductor substrate  34 , a liquid crystal molecule layer  30  positioned between the semiconductor substrate  34  and the glass substrate  32 , a transparent conductive layer  36  positioned on the liquid crystal molecule layer  30 , and a plurality of color filters  24   a ,  26   a ,  28   a  positioned between the transparent conductive layer  36  and the glass substrate  32 . 
   Since the shape of the pixels  22  of the present invention SLM is a parallelogram, the subpixels  24 ,  26 ,  28  positioned in the pixels  22  can be designed as different shapes to fully fill each of the pixels  22 . In the preferable embodiment of the present invention, the subpixels  26  and  28  have triangular shapes, and the subpixel  24  has a hexagon shape. In this design, the subpixels  24 ,  26 ,  28  can have shapes similar to a circular form. As shown in  FIG. 4 , the vertexes of each of the subpixels  24 ,  26 ,  28  are proximately positioned on a corresponding reference circle (as the dotted circles show in  FIG. 4 ), and the centers of the reference circles are positioned in the areas of the corresponding subpixels  24 ,  26 ,  28 . As a result, the subpixels  24 ,  26 ,  28  can supply uniform colors in each of the pixels  22 , and the present invention SLM can display preferable images accordingly. 
   Regarding the conventional pixels, the shapes of the subpixels positioned in the conventional pixels are limited to its rectangular shape. Please refer to  FIG. 7 , which is an enlarged view of a rectangular pixel. The conventional pixel  50  has a rectangular shape that is approximately square, and the shapes of the subpixels  52 ,  54 ,  56  are designed according to the arrangement of the present invention, which are a hexagon and two triangles. However, the shapes of the subpixels  52 ,  54 ,  56  in the rectangular pixel  50  are still similar to ellipses, instead of circles. As a result, comparing  FIG. 2 ,  FIG. 4 , and  FIG. 7 , the subpixels in the parallelogram pixels, such as the subpixels  24 ,  26 ,  28  in the pixel  22  shown in  FIG. 4  of the present invention, have better shapes than that of the subpixels in the rectangular pixel and can create preferable colors and display images. 
   In addition, the shapes and sizes of the subpixels in the pixels of the present invention SLM display panel can be changed for meeting the color taste of consumers provided that the adjusted shapes of the three subpixels form each pixel so as to manage the color of the SLM for meeting the color temperature requirement of the SLM. As shown in  FIG. 5 , the pixel  22  has a first side A and a second side B that have an included angle α that is an interior angle of the parallelogram pixel  22 . The SLM manufacturer can change the shape of the parallelogram pixel  22  through adjusting the first side A, the second side B, and their included angle α, so that the color temperature requirement can be met when the subpixels  24 ,  26 ,  28  have preferable shapes accordingly. In the preferable embodiment of the present invention, the pixel  22  is a diamond-shaped pixel. 
   Furthermore, for controlling the color temperature of the present invention SLM, the subpixels  24 ,  26 ,  28  can also be designed to have different areas. For example, the shapes of the subpixels  24 ,  26 ,  28  in the pixel  22  can be adjusted along the direction of the arrows shown in  FIG. 5 . When the SLM manufacturer wants to design an SLM that displays images with a warm color temperature, the SLM manufacturer can design to make the subpixels  24 ,  26 ,  28  have individual preferable areas and shapes through the above-mentioned process and make the red subpixel have the largest area. For example, the SLM manufacturer can position the red color filters corresponding to the subpixel  24  and make the red subpixel  24  have a larger area. For the same reason, the area of the subpixel  24  may be unequal to or larger than the areas of the other two subpixels  26  and  28 . Even more, the subpixel  26  may be still larger than the subpixel  28 . Similarly, the subpixels  24 ,  26 ,  28  can be designed as various shapes to accomplish the object of color management of an SLM by designing the shapes and areas of the subpixels according to the present invention. 
   Please refer to  FIG. 8 , which is an enlarged view of pixels  60  and  80  of an SLM of another embodiment according to the present invention. The pixels  60  and  80  each have trapezoid shapes, which have three triangular subpixels  60   a ,  60   b ,  60   c , and three triangular subpixels  80   a ,  80   b ,  80   c  respectively. In  FIG. 8 , the trapezoid pixels  60  and  80  form a regular hexagon, and all of the subpixels  60   a ,  60   b ,  60   c ,  80   a ,  80   b ,  80   c  are equilateral triangles. Consequently, the subpixels  60   a ,  60   b ,  60   c ,  80   a ,  80   b ,  80   c  all have areas similar to circles for providing preferable displaying colors. In addition, the SLM manufacturers still can adjust the shapes and sizes of the red, blue, and green subpixels according to the color temperature requirement and favorable color tones of the consumers. 
   To conclude the above description, the present invention provides a method for color management so that the SLM manufactures can produce SLMs satisfying the color tastes of consumers. Please refer to  FIG. 9 .  FIG. 9  is a flow chart of a method for color management of an SLM according to the present invention. The method of the present invention comprises the following steps: 
   Step  102 : Position a plurality of pixels with the same sizes and shapes arranged in a pixel array in the SLM. 
   Step  104 : Position a first subpixel, a second subpixel, and a third subpixel in each of the pixels, wherein the first, the second, and the third subpixels represent one of the optical fundamental colors, red, blue, and green. 
   Step  106 : Adjust shapes of the pixels according to a color temperature requirement of the SLM, wherein the adjusted shapes of the pixels are all the same. 
   Step  108 : Adjust shapes and areas of the first, the second, and the third subpixels according to the color temperature requirement of the SLM. 
   Step  110 : Position a plurality of color filters corresponding to the first, the second, and the third subpixels in the SLM, so that the first, the second, and the third subpixels display one of the optical fundamental colors when the SLM is operating. 
   In contrast to the prior art, the present invention provides pixels with shapes besides rectangles in the SLM, and further provides a method to design the arrangement of pixels through adjusting the shapes and sizes of the red, blue, and green subpixels, and adjusting the shapes of the pixels in order to meet the color temperature requirement of the SLM and the color taste of consumers. When the arrangement of the subpixels is changed according to the design, only the patterns of the photomasks for forming the color filters have to be changed. Therefore, the present invention method can be performed without changing fabricating processes. Accordingly, the present invention SLM and method can reach the goal of color management through simple processes without extra processes and costs. 
   Those skilled in the art will readily observe that numerous modifications and alterations of the device 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.