Abstract:
The invention discloses a projector apparatus for projecting an image onto a surface, comprising a light source module for generating a single first light path; a light beam homogenizer for inputting first light path to perform beam homogenization over the first light path; an illumination lens set for inputting the homogenized first light path and re-directing the first light path to a second light path, the first light path and the second light path forming an positive angle; a reflection-type image generator for generating said image; a prism set for inputting said second light path and outputting the second light path onto the reflection-type image generator, wherein the reflection-type image generator reflects the second light path and forming a third light path carrying said image, the third light path being reflected by said prism set to forming a fourth light path; an image projection lens set disposed on the fourth light path for projecting said image onto the surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This utility application claims priority to Taiwan application serial number 098129985, filed Sep. 7, 2009, which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This present invention relates to a projector apparatus, and relates to the pico projector apparatus, and particularly relates to the light path arrangement of pico projector apparatus. 
         [0004]    2. Description of the Prior Art 
         [0005]    Nowadays, the projector apparatus has extended its presence in the original business community into the household market or the portable mobile market. In the application of portable mobile market, the volume or size of projector apparatus is a major issue. In particular, reducing the thickness (i.e., height) of light source module and projecting module is the main goal the producers intend to achieve. 
         [0006]    In the state of arts, the light source module employing LED typically implements the dichroic combiner to form a single light path, which does not effectively reduce the size of light source module. In addition, the light beam homogenizer typically takes the form of light pipe, the length of which is also the reason why the size of light source module can not reduce. Furthermore, while employing a typical prism set to illuminate light source to a reflection-type image generator also negatively make a larger size in height (i.e. thickness) direction of the projecting module. 
         [0007]    Therefore, there is a strong need in the marketplace for a more miniaturized projector apparatus or module, that makes the projector apparatus portable or allows feasible implementation within other devices, such as mobile phone. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, one aspect of the invention is to provide a projector apparatus or module of miniaturized size. 
         [0009]    Another aspect of the invention is to provide a pico projecting module to be used with a mobile phone module making a mobile phone embedded with the projector function possible. 
         [0010]    Still another aspect of the invention is to provide a pico projecting module, wherein the light source may be implemented by a single light path design of LED light source. 
         [0011]    The above objectives of the invention may be achieved by a retro total internal reflection telecentric optical configuration or by a total internal reflection telecentric optical configuration 
         [0012]    Specifically, a retro total reflected telecentric optical configuration is provided comprising a prism set, wherein prism set comprising a first prism, the first prism including a main light inputting surface and a main light outputting surface, the main light inputting surface intersects with a vertical reference plane at a first angle, the main light outputting surface intersects with the vertical reference plane at a second angle, the first angle is about 28 (±3) degrees and the second angle is about 32 (±3) degrees. In one respect, this design can meet the need of the reflection-type image generator for irradiation (incidence) angle, and in another respect, this design can reduce the difference in height (thickness, i.e. in Y direction) direction between the prism set and the reflection-type image generator. 
         [0013]    In other words, to accomplish the above mentioned objective, the pico projector apparatus of the invention, which projects an image onto a surface, comprises a light source module, for generating a single first light path; a light beam homogenizer, inputting the first light path, for performing uniformity effect over the light of first light path; an illumination lens set, inputting the first light path going through the uniformity effect, for redirecting the first light path to a second light path, the first light path and the second light path forming a positive angle; a reflection-type image generator for forming the image; a prism set, inputting the second light path, for projecting the second light path onto the reflection-type image generator, wherein, after reflecting the second light path, the reflection-type image generator forms a third light path including the image, and as the third light path is reflected by the prism set, a fourth light path is generated; an image projection lens set, disposed on the fourth light path, for projecting the image onto the surface. 
         [0014]    Other than the first embodiment, the pico projector apparatus of second embodiment of the invention, which projecting an image onto a surface, comprises a light source module for generating a single first light path; a light beam homogenizer, inputting the first light path, for performing uniformity effect over the light of first light path; an illumination lens, inputting the first light path going through the uniformity effect, for further enhance the uniformity and illumination effect on the first light path; a reflection-type image generator forming the image; a prism set, inputting the first light path of enhanced uniformity and illumination effect, for totally reflecting the first light path forming a second light path to illuminate the reflection-type image generator, wherein, after the second light path is reflected, the reflection-type image generator forms a third light path including the image, the third light path passing through the prism set; an image projection lens set, disposed on the third light path, for projecting the image onto the surface. 
         [0015]    The aspect 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, which is illustrated in the following figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         [0016]      FIG. 1  shows the projector apparatus of first embodiment. 
           [0017]      FIG. 2   a  shows the perspective view of the first prism of the first embodiment. 
           [0018]      FIG. 2   b  shows the right side view of the first prism according to the first embodiment. 
           [0019]      FIG. 2   c  shows the top view of the first prism according to the first embodiment. 
           [0020]      FIG. 3  shows the projector apparatus of the second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Some preferred embodiments and practical applications of this present invention would be explained in the following paragraph, describing the characteristics, spirit and advantages of the invention. 
         [0022]    As shown in  FIG. 1 , the projector apparatus according to the preferred embodiment of the invention is utilized for projecting a image onto a surface, allowing people in front of the surface to view the content of the image. The projector apparatus might constitute a standalone projector, or might constitute a module which is a component of other portable device, e.g., a mobile phone, forming a portable combo machine, e.g., a mobile phone including the projector function. 
         [0023]    In the following recitations, the so-called ┌light path┘ means the path on which the light (with or without image) traveling through and the light per se. The light per se might not include any information, or, due to some image processing operation, e.g., the light is reflected by the reflection-type image generator, might include the information to be projected and displayed. For easy understanding and readability for the figures in this specification, only the main light line on the light path in all figures is shown and other non-main light lines are not shown for brevity. 
         [0024]    As shown in  FIG. 1 , except other components which already or will be in the market, the projector apparatus  100  of this invention comprises a light source module  110  for generating a single first light path L 10 ; a light beam homogenizer  120 , inputting the first light path L 10 , for performing uniformity effect on the light of first light path; an illumination lens set  130 , inputting the first light path L 10  going through the uniformity effect, for redirecting the first light path L 10  to a second light path L 13 , the first light path L 10  intersecting with the second light path L 13  at a positive angle; a reflection-type image generator  160 , for forming the image thereon; a prism set  140 , after inputting the second light path L 13 , projecting the second light path L 13  onto the reflection-type image generator  160 , wherein, after the reflection-type image generator  160  reflects the second light path L 13 , forming a third light path L 15  including the image, the third light path L 15  is totally reflected by the prism set  140  for generating a fourth light path L 17  including the image; an image projection lens set  170  disposed on the fourth light path L 17 , for projecting the mage of fourth light path L 17  onto the surface  180 . 
         [0025]    Under the structure of  FIG. 1 , in some embodiments, the light source module  110  comprises an LED light source  113  ∘ And the LED light source  113  takes the form of RGGB directly forming the single first light path L 10 , as shown in  FIG. 1 . Or, in other embodiments not shown in the drawings, the LED light source separately employs the R light source, the G light source, the B light source, and then via a dichroic combiner, the light source module  110  forming the single first light path L 10  by combining the R light source, G light source and B light source. For instance, the light-combination adopted by the U.S. patent application No. US 2006/0279710 A1, or the U.S. patent application No. US 2006/0164600 A1, or that adopted by the issued U.S. Pat. No. 6,644,814 B2. However, these approaches might result in larger size of projector apparatus. 
         [0026]    Under the structure of  FIG. 1 , in some embodiments, the light source module  110  comprises a light source  113  and a light source distribution modulation module ( 115 ,  117 ), the light source distribution modulation module ( 115 ,  117 ) inputting the light produced by the light source  113  and outputting the first light path L 10 . With regard to distribution of the illumination angle, the first light path L 10  emitting through the light source distribution modulation module ( 115 ,  117 ) has appropriate and evenly distribution, which is the main function of the light source distribution modulation module ( 115 ,  117 ). The preferred embodiments of light source distribution modulation module ( 115 ,  117 ) include the conventional collimator lens. 
         [0027]    Under the structure of  FIG. 1 , in some embodiments, the light beam homogenizer  120  includes a pico lenslet array, the pico lenslet array forming a light inputting surface  1201 , the light inputting surface  1201  is imaged on the reflection-type image generator  160 . As known to persons skilled in this arts, the pico lenslet array includes multiples of pico lens on an same surface and each pico lens typically has identical focal length. 
         [0028]    Under the structure of  FIG. 1 , in some embodiments, the curvature of radius of each pico lens within the pico lenslet array is about smaller than 2, thereby obtaining better light uniformity effect. As the first light path L 10  leaves the light beam homogenizer  120 , it irradiates the illumination lens set  130 , which redirects the first light path L 10  to a second light path L 13 , the first light path L 10  intersects with the second light path L 13  at a positive angle. 
         [0029]    The illumination lens set  130  mainly includes the illumination lens  131 ,  135  and direction guidance  133  (including, but not limited to, the reflection mirror). As known to persons skilled in the arts, the illumination lens  131 ,  135  mainly function to perform evenness effect on the distribution of light source illumination intensity, and also minimize the unevenness of low illumination intensity of light source. The embodiment for illumination lens  131  or illumination lens  135  might use the conventional condenser lens, which makes the main light line parallel to the light axis of projector apparatus and minimizes the deviation. The direction guidance  133  functions to redirect the first light path L 10  to a second light path L 13 . 
         [0030]    Under the structure of  FIG. 1 , in some embodiments, the prism set  140  includes a first prism  141 , wherein the first prism  141  includes a main light inputting surface S B  and a main light outputting surface S D , as shown in  FIGS. 2   a             2   b              2   c . The positive angle between the main light inputting surface S B  and a vertical reference plane S R  is a first angle, the positive angle between the main light outputting surface S D  and the vertical reference plane S R  is a second angle, the first angle is about 28 degree (±3 degree), and the second angle is about 32 degree (±3 degree), in order to meet the requirement of the reflection-type image generator  160  as to the light incidence angle. Under the structure of  FIG. 1 , in some embodiments, the prism set  140  includes a second prism  143 , wherein the second prism  143  is a total internal reflection prism. Since the second light path L 13  first penetrates the first prism  141 , then the second light path L 13  is reflected by the reflection-type image generator  160  obtaining the projection information reflected to form the third light path L 15 , the third light path L 15  is then totally reflected by the second prism  140  to form the fourth light path L 17 , the configuration on which this prism set  140  is applied is therefore named as retro total internal reflection telecentric optical configuration. 
         [0031]    As shown in the embodiment of  FIGS. 2   a             2   b             2   c  for the first prism  141 , the light enters through the inputting surface SB, outputs from the outputting surface SD, the disclosed design parameters of this first prism  141  (and/or the second prism  143 ) are only a preferred embodiment. Other different parameters, which also meet requirement of the reflection-type image generator  160  as to the light incidence angle, on one hand, and, on the other hand, might reduce the height (thickness, i.e., in Y direction) difference between the prism set  140  and the reflection-type image generator  160 , might be chosen. 
         [0032]    Looking back to  FIG. 1 , for some embodiments, the reflection-type image generator  160  includes a digital micromirrors device (DMD). A field lens  150  is typically arranged on the front side of the reflection-type image generator  160  which mainly functions to increase the viewing angle. 
         [0033]    The third light path L 15  including the projection information is totally reflected by the second prism  143  forming the fourth light path L 17 . This fourth light path L 17  passes through the image projection lens set  170 , and the information are projected onto the surface  180 . The image projection lens set  170   a  typically includes multiple lens of various functions to achieve magnification and projection functions. 
         [0034]    Due to the provision of embodiments shown in FIGS.  1             FIG. 2   a             FIG. 2   b             FIG. 2   c , the above invention objectives are achieved. Through simulations and experiments, as 0.22 inch DMD is used in configuration of the subject invention, the size of the projector apparatus can be lowered to 21.5 mm (X-lengthwise direction)*6.5 mm (Y-thickness direction)*20 mm (Z-widthwise direction), the total size is smaller than 3 cc, and still achieve level of 10 lm/W light efficiency. 
         [0035]    The second embodiment is described hereinafter. 
         [0036]    As shown in  FIG. 3 , except other components which already or will be in the projector apparatus market, the projector apparatus  300  of second embodiment includes a light source module  310  for generating a single first light path L 30 ; a light beam homogenizer  320 ; an illumination lens  330 ; a reflection-type image generator  360 ; and an image projection lens set  370 . 
         [0037]    The light beam homogenizer  320  inputs the first light path L 30  for performing uniformity effect over the first light path L 30 . The illumination lens  330  inputs the first light path L 30  having been performed the uniformity effect, for further enhancing the uniformity and illumination effect over the first light path L 30 . The reflection-type image generator  360  is used to form the image, and the prism set  340  functions to input the first light path L 30  of enhanced uniformity illumination effect. The first light path L 30  is then totally reflected forming a second light path L 33  illuminating reflection-type image generator  360 , the first light path L 30  and the second light path L 33  forms a positive angle. The reflection-type image generator  360  reflects the second light path L 33 , forming a third light path L 37  including the image, and the third light path L 37  passes through the prism set  340 . The image projection lens set  370  is disposed on the third light path L 37  for projecting the image onto the surface  380 . 
         [0038]    Under the structure of  FIG. 3 , in some embodiments, the light source module  310  includes a LED light source  313 . The LED light source  313  may take form of RGGB to directly form the single first light path L 30 , as shown in  FIG. 1 . 
         [0039]    Or, in embodiments not shown in the drawings, the LED light source separately employs the R light source, the G light source, the B light source, and then via a dichroic combiner, the light source module  310  forming the single first light path L 30  by combining the R light source, G light source and B light source. For instance, the light-combination adopted by the U.S. patent application No. US 2006/0279710 A1, or the U.S. patent application No. US 2006/0164600 A1, or that adopted by the issued U.S. Pat. No. 6,644,814 B2. However, these approaches might result in larger size of projector apparatus. 
         [0040]    Under the structure of  FIG. 3 , in some embodiments, the light source module  310  includes a light source  313  and a light source distribution modulation module ( 315 ,  317 ), light source distribution modulation module ( 315 ,  317 ) inputting the light generated by the light source  313  and outputting the first light path L 30 . In regard to the distribution of illumination angle, the first light path L 30  emitting from the light source distribution modulation module ( 315 ,  317 ) has appropriate and evenly distribution, which is the main function of the light source distribution modulation module ( 315 ,  317 ). The embodiments of light source distribution modulation module ( 315 ,  317 ) include the conventional collimator lens. 
         [0041]    Under the structure of  FIG. 3 , in some embodiments, the light beam homogenizer  320  includes a pico lenslet array, the pico lenslet array forms a light inputting surface  3201  which is imaged on the reflection-type image generator  360 . 
         [0042]    Under the structure of  FIG. 3 , in some embodiments, the curvature of radius of each pico lens of the pico lenslet array is about smaller than 2 in order to a better uniformity effect. 
         [0043]    As the first light path L 30  leaves the light beam homogenizer  320 , it irradiates the illumination lens set  330 . The illumination lens set  330  mainly includes the illumination lens  331 ,  333 . As known to persons skilled in the arts, the illumination lens  331 ,  333  mainly function to perform evenness effect on the distribution of light source illumination intensity, and also minimize the unevenness of low illumination intensity of light source. The embodiment for illumination lens  331  or illumination lens  333  might use the conventional condenser lens, which makes the main light line parallel to the light axis of projector apparatus and minimizes the deviation. 
         [0044]    Under the structure of  FIG. 3 , in some embodiments, the prism set  340  includes a first prism  341 , wherein first prism  341  includes a main light inputting surface S B a  and a main light outputting surface S D , as shown in  FIGS. 2   a             2   b             2   c . The positive angle between the main light inputting surface S B  and a vertical reference plane S R  is a first angle, the positive angle between the main light outputting surface S D  and the vertical reference plane S R  is a second angle, the first angle is about 28 degree (±3 degree), and the second angle is about 32 degree (±3 degree), in order to meet the requirement of the reflection-type image generator  360  as to the light incidence angle. The first prism  341  functions as a total internal reflection prism. Since first light path L 30  is first reflected by the first prism  341 , then reflected by the reflection-type image generator  360  for obtaining the projection information to form the third light path L 37 , the configuration of this prism set  340  in  FIG. 3  is therefore named as total internal reflection (TIR) telecentric optical configuration. However, the first prism  341  may implement other conventional type prisms that are different from that shown in  FIGS. 2   a             2   b             2   c.    
         [0045]    The design parameters of first prism  341  (and/or second prism  343 ) mainly, on one hand, to meet requirement of illumination angle of the reflection-type image generator  360 , and, on the other hand, to reduce the difference of height (thickness) (i.e., in Y direction) between the prism set  341  and the reflection-type image generator  360 . Under the configuration of  FIG. 3 , in some embodiments, the reflection-type image generator  360  includes a digital micromirrors device (DMD). A field lens  350 , which functions to increase the viewing angle, is typically provided on the front side of the reflection-type image generator  360 . 
         [0046]    The third light path L 37  including the projection information is totally reflected by the prism set  340 , and then it passes through image projection lens set  370 , and the information are projected onto the surface  380 . The image projection lens set  370   a  typically includes multiple lens of various functions to achieve magnification and projection functions. 
         [0047]    Due to the provision of embodiments shown in FIGS.  3             FIG. 2   a             FIG. 2   b             FIG. 2   c , the above invention objectives are achieved. Through simulations and experiments, as 0.22 inch DMD is used in configuration of the subject invention, the size of the projector apparatus can be lowered to 21.5 mm (X-lengthwise direction)*6.5 mm (Y-thickness direction)*20 mm (Z-widthwise direction), the total size is smaller than 3 cc, and still achieve level of 10 lm/W light efficiency. 
         [0048]    With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.