Abstract:
An auto-stereoscopic multi-dimensional display component is applicable for receiving and splitting a backlight source into waveband lights, and the waveband lights can be refracted to different positions of colored pixels. The multi-dimensional display component comprises a color grating element and a light guiding element; wherein the color grating element is configured to split and refract the backlight source, while the light guiding element emits the waveband lights towards the corresponding pixel positions. When the auto-stereoscopic multi-dimensional display component is applied in an image display device, it becomes a device of different dimensions according to its spectroscopical position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 100140604 filed in Taiwan, R.O.C. on Nov. 7, 2011, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a multi-dimensional display component and more particularly to an auto-stereoscopic multi-dimensional display component. 
         [0004]    2. Related Art 
         [0005]    Three-dimensional display technology is flourishing as it is becoming more popular and commercialized. An auto-stereoscopic technology is a type of three-dimensional display technologies, and it provides a convenience that viewers do not need to wear any auxiliary tools to view images presented by the auto-stereoscopic technology. Many are dedicated to researching the technology. 
         [0006]    Most conventional auto-stereoscopic displays use parallactic barrier or lenticular design, and the former employs a periodic grating disposed on a flat display. Because the periodic grating has alternate light transmitting and non-light transmitting vertical stripes, images shown by the display are transmitted to a user&#39;s left and right eyes as left and right images via the grating, and thus a stereo-effect is presented. For the barrier technology, only approximately 22% of the brilliance of the panel remains because half of the entire grating area is occupied by the non-light transmitting vertical stripes. 
         [0007]    The lenticular design of the latter employs the principle of geometrical optics, the left and right images displayed by the panel are respectively focused in the user&#39;s left and right eyes. Even though the problem with the reduced brilliance is improved by this method, problems with crosstalk of images and Moiré effect still exist. 
         [0008]    Even though the auto stereoscopic technology is being researched and developed continuously, the aforementioned problems with brilliance, crosstalk and overlapping patterns still exist. 
       SUMMARY 
       [0009]    According to an embodiment of the disclosure, the auto-stereoscopic multi-dimensional display component is applicable for receiving a backlight source and guiding it to a liquid crystal module, the liquid crystal module has a plurality of pixels, each of the pixels comprises a first sub-pixel, a second sub-pixel and a third sub-pixel, the auto-stereoscopic multi-dimensional display component comprises a color grating and a light guiding element. The color grating is for receiving the backlight source and splits the light from the light source into first, second and third waveband lights according to an optical wavelength of the backlight source. The color grating is disposed in the manner of mirror symmetry by a normal plane where the neighboring pixels are connected. The light guiding element is for receiving and guiding the first, the second and the third waveband lights for making the first guided waveband light pass through the first sub-pixel, the second guided waveband light pass through the second sub-pixel, and the third guided waveband light pass through the third sub-pixel. 
         [0010]    According to an embodiment of the disclosure, an auto-stereoscopic multi-dimensional display is formed by combining the auto-stereoscopic multi-dimensional display component with a backlight module and a liquid crystal module 
         [0011]    The structure and the technical means adopted by the present disclosure to achieve the above and other objects can be best understood by referring to the following detailed description of the embodiments and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present disclosure, and wherein: 
           [0013]      FIG. 1  is a perspective view of a first embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure being applied with a liquid crystal module; 
           [0014]      FIG. 2A  is a partial enlarged view of an auto-stereoscopic multi-dimensional display component of  FIG. 1 ; 
           [0015]      FIG. 2B  is a side view of an auto-stereoscopic multi-dimensional display component of  FIG. 1  being combined with a liquid crystal module; 
           [0016]      FIG. 3A  is an illustration of optical paths of an auto-stereoscopic stereo display effect of a first embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure being applied in a liquid crystal module; 
           [0017]      FIG. 3B  is an illustration of optical paths of a dual-dimensional display effect of a first embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure being applied in a liquid crystal module; 
           [0018]      FIG. 4  is a structural view of a second embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure; 
           [0019]      FIG. 5  is a structural view of a third embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure; and 
           [0020]      FIG. 6  is a structural view of a fourth embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The detailed characteristics and advantages of the disclosure are described in the following embodiments in details, the techniques of the disclosure can be easily understood and embodied by a person of average skill in the art, and the related objects and advantages of the disclosure can be easily understood by a person of average skill in the art by referring to the contents, the claims and the accompanying drawings disclosed in the specifications. 
         [0022]    Secondly, in the drawings of the disclosure, the specific elements are enlarged euphuistically for convenience of descriptions, thus the proportions between each of the elements are not drawn according to their dimensions, so that the shapes of the elements can be clearly shown, and the way the drawings being drawn should not be construed as limitative of the disclosure thereof. 
         [0023]      FIG. 1  is a perspective view of a first embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure being applied with a liquid crystal module. An auto-stereoscopic multi-dimensional display shown in  FIG. 1  comprises a back case  70 , a backlight module  40 , an auto-stereoscopic multi-dimensional display component  80 , a back glass  62 , a liquid crystal module  50 , a front glass  60  and a front case  72 . 
         [0024]    The backlight module  40  generates a backlight source and faces to the auto-stereoscopic multi-dimensional display component  80 . The backlight source can be a collimated light, and its collimated angle (referring to θ 3  in  FIG. 2B ) can be between 0 degree and 20 degrees. The collimated angle herein is an included angle between an axial direction of the backlight source and each of the light beams. The size of the collimated angle depends on the auto-stereoscopic multi-dimensional display component  80  in order to have fine image quality and to reduce the occurrence of crosstalk. The multi-dimension mentioned herein can be, but not limited to dual-dimension, stereoscopy, and above three-dimension. In this embodiment, three-dimensional stereoscopic display is used as an example, and it should not be construed as a limitation to practical applications. When the auto-stereoscopic multi-dimensional display component  80  is applied with the liquid crystal module  50 , an auto-stereoscopic effect can be presented for human eyes, or visual images of different contents can be displayed for human eyes at different positions. 
         [0025]    The liquid crystal module  50  comprises a plurality of pixels, Each of the pixels comprises a first sub-pixel, a second sub-pixel and a third sub-pixel. This will be described in details later. 
         [0026]    The auto-stereoscopic multi-dimensional display component  80  comprises a color grating  10  and a light guiding element  90 . The color grating  10  receives the backlight source and splits it into a first, a second and a third waveband lights according to an optical wavelength of the backlight source (it will be described in details later). The light guiding element  90  receives and guides the first, the second and the third waveband lights, so as to guide the first waveband light through the first sub-pixel, guide the second waveband light through the second sub-pixel, and guide the third waveband light through the third sub-pixel. By the light guiding element  90 , the waveband lights (including the first, the second and the third waveband lights) passed through the adjacent pixels can be converged at a viewer&#39;s left and right eyes at a specific distance from the auto-stereoscopic multi-dimensional display respectively. Therefore, when left and right multi-dimensional (stereo) images are respectively shown in the adjacent pixels of the liquid crystal module  50 , a displaying effect of multi-dimensional (stereo) images can be presented for the viewer. 
         [0027]    A detailed structure of the auto-stereoscopic multi-dimensional display component  80  can be best understood by referring to  FIGS. 2A and 2B .  FIG. 2A  is a partial enlarged view of the auto-stereoscopic multi-dimensional display component  80  of  FIG. 1 .  FIG. 2B  is a side view of the auto-stereoscopic multi-dimensional display component  80  of  FIG. 1  being combined with the liquid crystal module  50 . 
         [0028]    According to this embodiment, the liquid crystal module  50  comprises a plurality of pixels  52  and  54 , for convenience of descriptions, a first pixel  52  and a second pixel  54  are used for descriptions respectively, but it should not be construed as a limitation to the disclosure thereof, as the disclosure further comprises other pixels. The first pixel  52  and the second pixel  54  are disposed adjacent to each other, the first pixel  52  comprises a first sub-pixel  52 R, a second sub-pixel  52 G and a third sub-pixel  52 B. The first sub-pixel  52 R displays the red color (grayscale) of the first pixel  52 , the second sub-pixel  52 G displays the green color (grayscale) of the first pixel  52 , while the third sub-pixel  52 B displays the blue color (grayscale) of the first pixel  52 . By the same token, the second pixel  54  comprises a first sub-pixel  54 R, a second sub-pixel  54 G and a third sub-pixel  54 B. As shown in the drawing, the sub-pixels  52 R,  52 G and  52 B of the first pixel  52  and the sub-pixels  54 R,  54 G and  54 B of the second pixel  54  are disposed in the manner of mirror symmetry, but it should not be construed as a limitation to the disclosure thereof. The disposition of mirror symmetry herein can be referred to using a normal plane  56  (a vertical direction as shown in  FIG. 2B ) where the neighboring pixels such as the first pixel  52  and the second pixel  54  are connected for mirroring of symmetry. 
         [0029]    Although the first pixel  52  having three sub-pixels (the sub-pixels  52 R,  52 G,  52 B) and the second pixel  54  also having three sub-pixels (the sub-pixels  54 R,  54 G,  54 B) are taken as an example for descriptions, but it should not be construed as a limitation to the disclosure thereof, four or more than four sub-pixels can also be used in one pixel in other embodiments. 
         [0030]    The auto-stereoscopic multi-dimensional display component  80  comprises the color grating  10 , a convergent element  20  and a refractive element  30 . The aforementioned light guiding element  90  is composed of the convergent element  20  and the refractive element  30 . 
         [0031]    The color grating  10  is disposed in the manner of mirror symmetry by the normal plane  56  where the neighboring pixels such as the first pixel  52  and the second pixel  54  are connected. In detail, the color grating  10  comprises a plurality of micro prism arrays  12  and  14 , wherein the micro prism arrays  12  comprises micro prisms  12   a,    12   b,  and the micro prism arrays  14  comprises micro prisms  14   a,    14   b.  And the adjacent micro prism arrays  12  and  14  are disposed in the manner of mirror symmetry and corresponded to the first pixel  52  and the second pixel  54  respectively. More specifically, the symmetrical mirroring of the adjacent micro prism arrays  12  and  14  can be referred to using the normal plane  56  where the first pixel  52  and the second pixel  54  are connected for mirroring of symmetry. In an embodiment, a period of each of the micro prism arrays  12  and  14  can be between 0.1λ and 10λ, wherein λ is a wavelength of the waveband lights, λ can be a wavelength range of visible light, such as between 380 and 760 nanometers. In this embodiment, a period of each of the micro prism arrays  12  and  14  can be between 40 nm and 10 μm, in other words, a length in a horizontal direction of each of the micro prisms  12   a,    12   b,    14   a  and  14   b  in  FIG. 2B  can be between 40 nm and 10 μm. Furthermore, a period of the color grating  10  can be between 100 nm and 100 μm. 
         [0032]    The color grating  10  receives the backlight source  41  emitted by the backlight module  40  and splits it into first waveband lights  42 R and  44 R, second waveband lights  42 G and  44 G and third waveband lights  42 B and  44 B according to an optical wavelength of the backlight source  41 . Indications of light beams of the waveband lights  42 R,  42 G,  42 B,  44 R,  44 G and  44 B in the drawing are for illustration only and should be construed as limitation to the disclosure thereof. 
         [0033]    An optical wavelength range of the first waveband lights  42 R and  44 R can be, but not limited to, 615 nm and 635 nm. An optical wavelength range of the second waveband lights  42 G and  44 G can be, but not limited to, 515 nm and 535 nm. An optical wavelength range of the third waveband lights  42 B and  44 B can be, but not limited to, 465 nm and 485 nm. As shown in the drawing, the first waveband light  42 R, the second waveband light  42 G and the third waveband light  42 B respectively enters into the convergent element  20  of the light guiding element  90  by travelling along sequentially adjacent first direction, second direction and third direction. An included angle θ 2  between the first direction and the second direction is larger than 0.5 degree and smaller than 30 degrees, an included angle θ 1  between the second direction and the third direction is larger than 0.5 degree and smaller than 30 degrees. The first, second and third directions mentioned herein are referred to main travelling directions (the travelling directions of most of the waveband light beams) of the corresponding waveband lights, but not to travelling directions of all of the corresponding waveband lights. In an embodiment, relationships between the included angles θ 1 , θ 2  and the aforementioned collimated angle θ 3  can be, but not limited to, θ 1 =θ 2 , θ 1 ≦θ 3 . In other words, the included angles θ 1  and θ 2  are also formed by the first waveband light  44 R, the second waveband light  44 G and the third waveband light  44 B, which will not be mentioned herein again. 
         [0034]    The wavelength ranges of the aforementioned waveband lights are not limited to the abovementioned examples, the waveband lights can be waveband lights of cyan, magenta and yellow. 
         [0035]    Each of the waveband lights  42 R,  42 G,  42 B,  44 R,  44 G and  44 B enters into the light guiding element  90  subsequently and are received by the convergent element  20 . 
         [0036]    The convergent element  20  receives and converges the first waveband lights  42 R,  44 R, the second waveband lights  42 G,  44 G and the third waveband lights  42 B,  44 B respectively. The refractive element  30  refracts the first converged waveband lights  42 R′,  44 R′ (indicated by solid lines) so that they pass through the first corresponding sub-pixels  52 R,  54 R respectively, refracts the second converged waveband lights  42 G′,  44 G′ (indicated by broken lines) so that they pass through the second corresponding sub-pixels  52 G,  54 G respectively, and refracts the third converged waveband lights  42 B′,  44 B′ (indicated by dotted lines) so that they pass through the third corresponding sub-pixels  52 B,  54 B respectively. The refracted and converged waveband lights passing through the sub-pixels mentioned herein is not referred to a 100% of the refracted and converged waveband lights is passed through the sub-pixels; and when the embodiment is implemented, an effect of the disclosure can be achieved by allowing a 60% of the refracted and converged waveband lights passing through the sub-pixels by using the light guiding element  90 . 
         [0037]    After the first waveband lights  42 R′,  44 R′, the second waveband lights  42 G′,  44 G′ and the third waveband lights  42 B′,  44 B′ refracted by the refractive element  30  have passed through the first sub-pixels  52 R,  54 R, the second sub-pixels  52 G,  54 G and the third sub-pixels  52 B,  54 B correspondingly and respectively, they are formed as images at locations, such as the viewer&#39;s left and right eyes, which are at a specific distance from the auto-stereoscopic multi-dimensional display; and the adjacent first and second pixels  52  and  54  are formed as images in the viewer&#39;s left and right eyes respectively, so that an effect of multi-dimensional (stereo) images is presented. 
         [0038]    The convergent element  20  comprises a plurality of lenses  22  and  24 . In an embodiment, the lenses can be micro lenses. In this embodiment, the lenses  22  and  24  are convex lenses. Each of the lenses  22  and  24  corresponds to one of the pixels  52  and  54  respectively. In other words, the first lens  22  corresponds to the first pixel  52 , the second lens  24  corresponds to the second pixel  54 . The adjacent first and second lenses  22  and  24  are disposed in such a way that they are mirrored symmetrically. A period of the first and second lenses  22  and  24  on the convergent element  20  can be, but not limited to between 0.1λ and 2000λ. In another embodiment, a period of the first and second lenses  22  and  24  on the convergent element  20  can be between 40 nm to 1 mm. The period of the first and second lenses  22  and  24  herein is referred to a length (i.e. a horizontal length shown in  FIG. 2B ) of a base of the first and second lenses  22  and  24 . Furthermore, the convex lens can be a uni-dimensional lenticular lens, a dual-dimensional convex curved mirror or a dual-dimensional concave curved mirror, wherein a curved surface of the aforementioned curved mirror can be a paraboloid, a sphere, a hyperboloid, a freeform surface, etc. 
         [0039]    Referring to  FIG. 2B  for details, a first middle layer  18  is further disposed between the color grating  10  and the convergent element  20 , the first middle layer  18  can be air or a plastic material, wherein an index of refraction of the plastic material is between 1.0 and 1.45, the plastic material can be such as: an airgel, a fluorinated monomeric composite of fluorinated poly-functional (meth) acrylic esters, nanoporous silica or silsesquioxane, or mesoporous silica, but is not limited to the materials given above. Furthermore, a second middle layer  28  is further disposed between the convergent element  20  and the refractive element  30 , the second middle layer  28  can be air, a maximum distance H (i.e. a maximum height of the second middle layer  28 ) between the convergent element  20  and the refractive element  30  can be between 0.01 mm and 50 mm. 
         [0040]    It can be known from  FIG. 2B  that, the convergent element  20  further comprises a base plate  26 , the first and the second lenses  22  and  24  are disposed on the base plate  26 . The base plate  26  as well as the first and the second lenses  22  and  24  can be made of a same material or different materials, that means an index of refraction of the base plate  26  can be the same as or different from that of the first and second lenses  22  and  24 . The first and the second lenses  22  and  24  can be first and the second lenses  22  and  24  formed by printing on the base plate  26 , but are not limited to them. A material of the base plate  26  as well as the first and second lenses  22  and  24  can be, but not limited to a glass, polycarbonate (PC) or polymethylmethacrylate (PMMA). 
         [0041]    The refractive element  30  comprises a plurality of adjacent triangular prisms  32  and  34 , the triangular prisms  32  and  34  can be disposed on a back glass  62 , each of the triangular prisms  32  and  34  corresponds to one of the pixels  52  and  54 . As shown in the drawing, the first triangular prism  32  corresponds to the first pixel  52 , and the second triangular prism  34  corresponds to the second pixel  54 . In an embodiment, the first and second triangular prisms  32  and  34  can be a right angled triangular prism, while the first and second triangular prisms  32  and  34  can also be a micro multilateral refractive element in other embodiments. The bases (i.e. a side in a horizontal direction shown in  FIG. 2B ) of the first and the second triangular prisms  32  and  34  are connected with each other, coplanar substantially and facing to the liquid crystal module  50 , and the adjacent first and second triangular prisms  32  and  34  are disposed in such a way that they are mirrored symmetrically by the normal plane  56 . A material of the refractive element  30  can be a polarizing material such as polyvinyl alcohol (PVA) or polymer-dispersed liquid crystal (PDLC) film, but is not limited to them. A period of the first and second triangular prisms  32  and  34  on the refractive element  30  can be between 0.1λ and 2000λ, but is not limited to it; in another embodiment, a period of the first and second triangular prisms  32  and  34  on the refractive element  30  can be between 40 nm and 1 mm. 
         [0042]    Referring to  FIG. 3A , which is an illustration of optical paths of an auto-stereoscopic stereo display effect of a first embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure being applied in a liquid crystal module. The optical paths in  FIG. 3A  are illustrated in a way that red lights are indicated by solid lines, green lights are indicated by broken lines, while blue lights are indicated by dotted lines. Only four adjacent pixels  52 ,  54 ,  52 ′ and  54 ′ are shown in  FIG. 3A ; images presented by the first pixels  52  and  52 ′ are a first portion of a stereo-image, while images presented by the second pixels  54  and  54 ′ are a second portion of the stereo-image. Therefore, after the backlight source  41  is sequentially split, converged and refracted by the color grating  10 , the convergent element  20  and the refractive element  30  sequentially, then the two aforementioned portions of the stereo-image can be projected to a viewer&#39;s left and right eyes  82   a  and  82   b  respectively, thereby, a stereo-perception is created for the viewer. 
         [0043]    Referring to  FIG. 3B , which is an illustration of optical paths of a dual-dimensional display effect of a first embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure being applied in a liquid crystal module. Here, only the four adjacent pixels  52 ,  54 ,  52 ′ and  54 ′ are shown in  FIG. 3B , and thus images presented by the first pixels  52  and  52 ′ are a first image, while images presented by the second pixels  54  and  54 ′ are a second image, therefore the first image and the second image are different from each other, for example, different movies or different programs, but are not limited to them. As shown in  FIG. 3B , after the backlight source  41  is sequentially split, converged and refracted by the color grating  10 , the convergent element  20  and the refractive element  30  sequentially, the two aforementioned portions of the stereo-image can be projected to two viewers&#39; left and right eyes  82   a,    82   b,    84   a  and  84   b  respectively. In this way, the first image is seen by the first viewer (corresponding to the eyes  82   a  and  82   b ), while the second image is seen by the second viewer (corresponding to the eyes  84   a  and  84   b ). Therefore, a dual-dimensional displaying effect can be realized by the auto-stereoscopic multi-dimensional display component. Furthermore, the color grating  10 , the convergent element  20  and the refractive element  30  can be designed applicably by the discloser of the disclosure to be used with the pixels  52 ,  54 ,  52 ′ and  54 ′, thereby more than two images of different pictures can be presented for viewing by many viewers at a same time interval. 
         [0044]    According to the abovementioned descriptions, when the auto-stereoscopic multi-dimensional display component  80  is used with the backlight module  40  and the liquid crystal module  50 , a multi-dimensional visual effect can be provided for the viewers. 
         [0045]    Referring to  FIG. 4 , which is a structural view of a second embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure. As shown in the drawing, an auto-stereoscopic multi-dimensional display component comprises the color grating  10 , a convergent element  20 ′ and the refractive element  30 . The elements in this embodiment are similar to those of the first embodiment, wherein the convergent element  20 ′ comprises a plurality of concave lenses  22 ′ and  24 ′, the concave lenses  22 ′ and  24 ′ are disposed on the base plate  26 , and the color grating  10  is also disposed on the base plate  26 , the color grating  10  and the concave lenses  22 ′ and  24 ′ are disposed on two opposite surfaces of the base plate  26  respectively to form a dual layered structure of films. 
         [0046]    Referring to  FIG. 5 , which is a structural view of a third embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure. An auto-stereoscopic multi-dimensional display component of the third embodiment comprises the color grating  10  and the convergent element  20 . The difference between the third embodiment and the first embodiment lie in that, the refractive element  30  is omitted in the third embodiment. The refractive element  30  provides a suitable refracting capability for the light guiding element  90 . In other words, by a disposition of the refractive element  30  in the first embodiment, distances between the liquid crystal module  50  and the color grating  10 , the convergent element  20  are shorter than those in the third embodiment. 
         [0047]    In the third embodiment, the convergent element  20  receives and converges the first, the second and the third waveband lights  42 R,  44 R,  42 G,  44 G,  42 B and  44 B, so that the first converged waveband lights  42 R and  44 R pass through the first corresponding sub-pixels  52 R and  54 R respectively, the second converged waveband lights  42 G and  44 G pass through the second corresponding sub-pixels  52 G and  54 G respectively, and the third converged waveband lights  42 B and  44 B pass through the third corresponding sub-pixels  52 B and  54 B respectively. The included angles  01  and  02  between the first waveband lights  42 R and  44 R, the second waveband lights  42 G and  44 G and the third waveband lights  42 B and  44 B after split by the color grating  10  can be less than 1 degree. The color grating  10  comprises a plurality of micro prism arrays, and a period of each of the micro prism arrays is between 6 microns and 60 microns. 
         [0048]    Referring to  FIG. 6 , which is a structural view of a fourth embodiment of an auto-stereoscopic multi-dimensional display component according to the disclosure. An auto-stereoscopic multi-dimensional display component of the fourth embodiment comprises the color grating  10  and a light guiding element  90 ′. The light guiding element  90 ′ integrates the convergent element  20  and the refractive element  30  in the first embodiment into a single element. The light guiding element  90 ′ comprises a plurality of freeform micro composite lenses  92  and  94 . Each of the micro composite lenses  92  and  94  corresponds to one of the pixels  52  and  54 ; each of the micro composite lenses  92  and  94  receives and converges the first waveband lights  42 R and  44 R, the second waveband lights  42 G and  44 G and the third waveband lights  42 B and  44 B correspondingly, so that the first converged waveband lights  42 R′ and  44 R′ pass through the first corresponding sub-pixels  52 R and  54 R, the second converged waveband lights  42 G′ and  44 G′ pass through the second corresponding sub-pixels  52 G and  54 G, and the third converged waveband lights  42 B′ and  44 B′ pass through the third corresponding sub-pixels  52 B and  54 B. 
         [0049]    The aforementioned freeform micro composite lenses  92  and  94  can be designed based on requirements of convergence and refraction. In this embodiment, each of the freeform micro composite lenses  92  and  94  corresponds to one of the pixels  52  and  54  respectively; each of the freeform micro composite lenses  92  and  94  receives and converges the first, the second and the third waveband lights  42 R,  44 R,  42 G,  44 G,  42 B and  44 B, so that the first converged waveband lights  42 R and  44 R pass through the first corresponding sub-pixels  52 R and  54 R respectively, the second converged waveband lights  42 G and  44 G pass through the second corresponding sub-pixels  52 G and  54 G respectively, and the third converged waveband lights  42 B and  44 B pass through the third corresponding sub-pixels  52 B and  54 B respectively. 
         [0050]    Take the micro composite lens  94  for an example, it is roughly triangular and has three sides  940 ,  942  and  944 , wherein the base  940  is a flat side, the first slant side  942  and the second slant side  944  are curved sides, the first slant side  942  and the second slant side  944  intersects at an apex, a horizontal distance (i.e. a distance the first slant side  942  projected to the base  940 ) from the apex to another end of the first slant side  942  is L 1 , a horizontal distance (i.e. a distance the second slant side  944  projected to the base  940 ) from the apex to another end of the second slant side  944  is L 2 , a vertical distance (height) from the apex to the base  940  is L 3 , wherein L 1 :L 2 :L 3  is approximately 45:1:10, and a radius of curvature of the first slant side  942  is approximately 4250 microns, a length (L 1 +L 2 ) of the base  940  is approximately 190 microns, a radius of curvature of the second slant side  944  is approximately 4246 microns. 
         [0051]    Note that the specifications relating to the above embodiments should be construed as exemplary rather than as limitative of the disclosure, with many variations and modifications being readily attainable by a person of average skill in the art without departing from the spirit or scope thereof as defined by the appended claims and their legal equivalents.