Abstract:
A projection device having single light valve has a light source, a projection lens, an imaging unit and a beam breaker. Moreover, the imaging unit has a color production device and a valve. When the beam provided by light source propagates to the color production device, the color production device converts the beam into several different color beams in an order. Thereafter, the beams propagate to the beam breaker, and the beam breaker breaks the beam propagating through within a definite time according to the states of imaging unit. Afterwards, the beams that are not broken are converted into images by the light valve in order, and projected on a screen by projection lens. The beam breaker module can enable the projection device having single light to have several situation modes, and maintain the imaging contrast.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention relates to a projection device having single light valve. More particularly, the present invention relates to a projection device having single light valve, which can be operated under various operation modes with the effect of image contrast simultaneously. 
   2. Description of Related Art 
   In recent years, the cathode ray tube (CRT) projection device, which has large volume and is heavy, has been gradually replaced by the products, such as the LCD projection device and digital light processing (DLP) projection device. These products has the characteristics of being light and portable, and can be directly coupled with the digital products, so as to display the image by projection. Under the situation that the manufacturers are continuously developing cheaper and competitive products with additional function, these products can not only be used in company, school, or a public area for briefing, but also gradually be developed as a tool for viewing a movie at home. Wherein, the use in briefing needs high brightness, but the use for view the movie needs high saturation degree. In this consideration, it is a trend to have a projection device, which has capability of both high brightness and high saturation. 
     FIG. 1  is a drawing, schematically illustrating the structure of a conventional projection device having single light valve. In  FIG. 1 , the conventional projection device having single light valve  100  includes a light source  110 , a projection lens  120 , an image unit  130 , and a control unit  150 . Wherein, the light source  110  is used to provide a light beam  112 . In addition, the projection lens  120  is disposed behind the light source  110 , and is on the propagating path of the light beam  112 . 
   In the foregoing projection device having single light valve  100 , the image unit  130  is disposed between the light source  110  and the projection lens  120 , and is on the propagating path of the light beam  112 . The conventional image unit  130  includes a color wheel  132  and a digital micro-lens device  134 , wherein the digital micro-lens device  134  is disposed behind the color wheel  132 , and is on the propagating path of the light beam  112 . The control unit  150  is used to synchronously control the color wheel  132  and the digital micro-lens device  134 . The control unit  150  includes a color wheel driver  156  and a digital micro-lens device driver  152 . Wherein the digital micro-lens device driver  152  is electrically coupled to the digital micro-lens device  134 , and the color wheel driver  156  is electrically coupled to the color wheel  132 . In addition, the digital micro-lens device driver  152  and the color wheel driver  156  of the control unit  150  are used to synchronously control the digital micro-lens device  134  and the color wheel  132 . 
   According to the foregoing descriptions, the light beam  112  provided by the light source  110  propagates to the color wheel  132  of the image unit  130 . And then, the color wheel driver  156  of the control unit  150  controls the color wheel  132  being electrically coupled thereto, so as to sequentially divide the light beam  112  into light beams  112  in different colors. Then, these light beams  112  are sequentially incident to the digital micro-lens device  134  with multiple pixel units, which are controlled by the digital micro-lens device driver  152 , which is electrically coupled therewith, so as to have the displaying states of ON state or Off state. The pixel units with the ON state cause the light beams  112  to be reflected to the projection lens  120 . The pixel units with the OFF state cause the light beams  112  to be deviating off the projection lens  120 . After then, the projection lens  120  projects the light beams (image), which have been processed by the digital micro-lens device  134 , onto the screen S. 
   According to the foregoing descriptions, the conventional projection device having single light valve  100  uses the color wheels  132  with red (R) filtering region, green (G) filtering region, and blue (B) filtering region. However, since the spoke regions between each of the color filtering regions on the color wheel  132  have the noise light, the color saturation of the projected image would get worse. In addition, since the dark image (all of the pixel units of the digital micro-lens device are at OFF state) still has some noise light, the contrast of the projected image is lowered either. 
   In order to increase the image brightness for allowing the projection device having single light valve  100  to have various operation modes with high brightness and high color saturation, the conventional technology needs to use the color wheel  132  with the red filtering region, the green filtering region, the blue filtering region, and the white (W) filtering region for increasing the image brightness, but the color saturation would be reduced in this manner. When the mode with high color saturation is needed, the digital micro-lens device driver  152  does not process a portion or the whole of the light beam that passes through the white filtering region, or does not process a portion or the whole of the light beam that passes through each of the filtering regions, so as to increase the color saturation. In the foregoing methods, under the high brightness mode, the brightness for the white image is the brightness from the R, G, B, and W light beams. The brightness of the dark image is due to the brightness of noise lights from the R, G, B, and W light beams. When under the high color saturation mode, the brightness for the white image is the brightness from the R, G, B, and W light beams and the brightness of the dark image is also due to the brightness of noise lights from the R, G, B, and W light beams. Therefore, the image brightness of white image under the high color saturation mode would decrease, and the noise light from the W light beam still exists in the dark image, and the brightness of the dark image is not changed. As a result, the contrast under the high color saturation mode is reduced. The data is shown in Table 1 for clear comparison on the difference: 
   
     
       
             
             
             
             
           
             
             
             
             
           
         
             
                 
               TABLE 1 
             
             
                 
                 
             
             
                 
               Brightness for 
               Brightness for 
                 
             
             
                 
               white image 
               dark image 
               Contrast 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
               High brightness mode 
               1000 (Lux)  
               1 (Lux) 
               1000 
             
             
               High color saturation mode 
               500 (Lux) 
               1 (Lux) 
               500 
             
             
                 
             
           
        
       
     
   
   Therefore, the foregoing projection device cannot be adapted to various operation modes, such as high image brightness or high color saturation, to always provide the better contrast. 
   SUMMARY OF THE INVENTION 
   One of the objects of the invention is to provide a projection device having single light valve, which can be used in various operation modes with consideration of image contrast. 
   For at least achieving the foregoing object, the invention provides a projection device having single light valve, suitable for use to project an image to a screen. The projection device having single light valve includes a light source, a projection lens, an image unit, and a beam breaker module. Wherein, the light source is used to provide a light beam. In addition, the projection lens is disposed behind the light source and is located on the propagation path of the light beam. 
   In the foregoing projection device having single light valve, the image unit is disposed between the light source and the projection lens, and is located on the propagation path of the light beam. This image unit includes a color production device and a light valve. Wherein, the light valve is disposed behind the color production device, and is located on the propagation path of the light beam. In addition, the beam breaker module is disposed between the light source and the screen, and is located on the propagation path of the light beam. Wherein, the beam breaker module is to break the passing light beam within a specific time period, according to the state of the color production device. 
   In the foregoing projection device having single light valve, the color production device includes a color wheel. The color wheel includes, for example, a red filtering region, a green filtering region, and a blue filtering region, or includes a red filtering region, a green filtering region, a blue filtering region, and a white filtering region. In addition, the color wheel can include, for example, a yellow (Y) filtering ring, a magenta (M) filtering region, and a cyan (C) filtering region, or includes a yellow filtering ring, a magenta filtering region, a cyan filtering region, and a white (W) filtering region. 
   In the foregoing projection device having single light valve, the color production device includes, for example, a color drum. The color drum includes, for example, a red filtering region, a green filtering region, and a blue filtering region, or includes a red filtering region, a green filtering region, a blue filtering region, and a white filtering region. In addition, the color drum can include, for example, a yellow (Y) filtering ring, a magenta (M) filtering region, and a cyan (C) filtering region, or includes a yellow filtering ring, a magenta filtering region, a cyan filtering region, and a white (W) filtering region. 
   In the foregoing projection device having single light valve, the light valve includes, for example, a liquid crystal display, a digital micro-lens device, or a reflective-type liquid crystal on silicon (LCOS) display. 
   In the foregoing projection device having single light valve, the beam breaker module is disposed, for example, between the light source and the image unit, in the image unit, between the image unit and the projection lens, in the projection lens, or between the projection lens and the screen. The beam breaker module includes, for example, an optical sensor, a beam breaking part, and an actuator. In addition, the optical sensor is disposed beside the color production device, so as to sense the state of the color production device. Moreover, the beam breaking part is between the light source and the screen, and the actuator is coupled with the beam breaking part. 
   In the foregoing projection device having single light valve, for example, it further includes a control unit to synchronously control the color production device, the light valve and the beam breaker module. The control unit includes, for example, a light valve driver, an actuator driver, and a color production device driver. Wherein, the light valve driver is electrically coupled with the light valve. In addition, the actuator driver and the actuator are electrically coupled, so as to control the beam breaking part. In addition, the color production device driver and the color production device driver are electrically coupled, wherein the light valve driver, the actuator driver and the color production device driver in synchronous use to control the light valve, the beam breaker module, and the color production device. 
   The invention uses the beam breaker module, which is disposed between the light source and the screen, and is on the light propagation path. This beam breaker module can break the light beam within a specific time period, according to the state of the color production device. Therefore, the projection device having single light valve can be used in various operation modes with capability of maintaining the contrast. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
       FIG. 1  is a drawing, schematically illustrating the structure of a conventional projection device having single light valve. 
       FIG. 2  is a drawing, schematically illustrating the structure of a projection device having single light valve, according to an embodiment of the present invention. 
       FIG. 3  is a cross-section view, schematically the structure cutting along the line I-I in  FIG. 2 . 
       FIGS. 4A-4D  are drawings, schematically illustrating disposing positions of the beam breaking part. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2  is a drawing, schematically illustrating the structure of a projection device having single light valve, according to an embodiment of the present invention. In  FIG. 2 , the invention proposes a projection device having single light valve  200 , which can project an image (not shown) to a screen S. The projection device having single light valve  200  includes a light source  210 , a projection lens  220 , an image unit  230 , and a beam breaker module  240 . In the foregoing projection device having single light valve  200 , the light source  210  can provide a light beam  212 . The projection lens  220  is disposed behind the light source  210 , and is located on the propagation pat of the light beam  212 . In addition, the image unit  230  is disposed between the light source  210  and the projection lens  220 , and is located on die propagation path of the light beam  212 . 
   In the embodiment of the invention, the image unit  230  includes, for example, a color production device  232  and a light valve  234 . Wherein, the light valve  234  is disposed behind the color production device  232 , and is located on the propagation path of the light beam  212 . In addition, the beam breaker module  240  is, for example, disposed between the light source  210  and the screen S, and the beam breaker module  240  can selectively cut in or cut out the propagation path of the light beam. When the beam breaker module  240  cuts in the propagation path of the light beam, the beam breaker module  240  can break the passing light beam within a specific time period according to the state of the color production device  232 . 
   In the foregoing projection device having single light valve  200 , the color production device  232  includes for example a color wheel or a color drum, wherein the color wheel is shown in  FIG. 2 . Moreover, the color wheel (color drum) is composed of several filtering regions in various arrangements, such as a red color filtering region, a green filtering region, and a blue filtering region, or a red color filtering region, a green filtering region, a blue filtering region, and a white filtering region. It can also include a yellow filtering region a magenta filtering region, and a cyan filtering region, or include a yellow filtering region, a magenta filtering region, a cyan filtering region, and a white filtering region. 
   In the foregoing projection device having single light valve  200 , the beam breaker module  240  includes, for example. an optical sensor  242 , a beam breaking part  244  and an actuator  246 . Wherein, the optical sensor  242  is disposed beside the color production device  232 , so as to sense the state of the color production device  232 . Moreover, the beam breaking part  244  can include metal plate or a plate with black coating the surface, so as to reflect or absorb the light beam. The actuator  246  is coupled with the beam breaking part  244 , so as to control the beam breaking part  244  to cut in or cut out from the propagation path of the light beam. The actuator  246  can be a motor or a magnetic switch. 
     FIGS. 4A-4D  are drawings, schematically illustrating disposing positions of the beam breaking part. In  FIG. 2  and  FIGS. 4A-4D , the location of the foregoing beam breaking part  244  is not limited to the way, as shown in  FIG. 2 , disposed in the image unit  230 . The beam breaking part  244  can be disposed between the light source  210  and the screen S. As shown in  FIG. 4A , the beam breaking part  244  can be, for example, disposed between the light source  210  and the image unit  230 .  FIG. 4A  shows the location between the light source  210  and the color production device  232 . In addition, as shown in  FIG. 4B , the beam breaking part  244  can be disposed, for example, between the image unit  230  and the projection lens  220 . As shown in  FIG. 4B , the location is between the light valve  234  and the projection lens  220 . In addition, the light breaking part  244  can, for example, disposed inside the projection lens  220 , as shown in  FIG. 4C , or is disposed between the projection lens  220  and the screen S, as shown in  FIG. 4D . 
   Also referring to  FIG. 2 , the projection device having single light valve  200  of the invention can further include a control unit  250 , so as to synchronously control the color production device  232 , the light valve  234 , and the beam breaker module  240 . The control unit  250  can be, for example, a circuit board, which includes, for example, a light valve driver  252 , an actuator driver  254 , and a color production device driver  256 . Wherein, the light valve driver  252  and the light valve  242  are electrically coupled. In addition, the actuator driver  254  and the actuator  246  are electrically coupled, so as to control the beam breaking part  244 . Moreover, the color production device driver  256  and the color production device  232  are electrically coupled, wherein the light valve driver  252 , the actuator driver  254 , and the color production device driver  256  are used to synchronously control the light valve  234 , the beam breaker module  240 , and the color production device  232 . 
     FIG. 3  is a cross-section view, schematically illustrating the structure cutting along the line I-I in  FIG. 2 . In  FIGS. 2 and 3 , when the beam breaker module  240  cuts in the propagation path of the light beam, the light beam  212  provided from the light source  210  propagates to the color production device  232  of the image unit  230 . The color production device  232  can be, for example, a color wheel having a red filtering region R, a green filtering region G, a blue filtering region B, and a white filtering region W. Then, the color production device driver  256  of the control unit  250  synchronously controls the color production device  232  being electrically coupled thereto, so as to divide the light beam  212  into light beams with different color in an order, such as the light beams  212  in the order of a red light, a green light, a blue light, and a white light. In addition, the optical sensor  242  being disposed beside the color production device  232  would sense the state of the color production device  232 , and a synchronous signal, which represents the state of the color production device  232 , is sent back to the control unit  250 . Then, these light beams  212  are sequentially propagating to the beam breaking part  244 . At this moment, the control unit  250  controls the actuator  246  by the actuator driver  254 , according to the synchronous signal sent from the optical sensor  242 , so as to further control the beam breaking part  244  to break the passing light beam  212  Within a specific period. In the embodiment, for example, the passing light beam  212 , which has passed through the white filtering region W, can be broken. Or, for example, the noise light caused by the interfacing region E between the filtering regions can be broken, so as to improve the color saturation level of the image. In the embodiment, it can break the light beam  212  passing the white filtering region W and the noise light caused by the interfacing region E between the filtering regions, so as to both improving the color saturation level of the image and the contrast. After then, the light beams without being broken would enter a light valve  234 . The light valve  234  includes, for example, a liquid crystal display (LCD), a digital micro-lens device (DMD), or a reflective-type LCOS. In the embodiment, a DMD with multiple pixel units is taken as an example as the light valve  232  for description. The pixel units of the light valve  232  are synchronously controlled byte electrically coupled light valve driver  252 , so as to respectively have the ON states or the OFF states. The pixel unit with the ON state would cause the light beam  212  to be reflected to the projection lens  220 . The pixel unit with OFF state would cause the light beam  212  to be off the projection lens  220 . After then, the projection lens  220  projects the light beam  212  (image), which has been processed by the light valve  232 , to the screen S. 
   When the beam breaker module  240  cuts out the propagation path of the light beam, the manner for displaying image on the screen S can be referred to  FIG. 1 , the light beam  112  provided from the light source  110  propagates to the color wheel  132 . Then, the color wheel driver  156  of the control unit  150  controls the color wheel  132 , which is electrically coupled thereto. As a result, the light beam  212  is divided into several light beams  212  in different color by an order. Then, the light beams  212  sequentially enter the DMD  134  with multiple pixel units. The pixel units are controlled by the DMD driver  152  being electrically coupled thereto, so as to have the ON state and the OFF state. The pixel unit with the ON state would cause the light beam  112  to be reflected to the projection lens  120 . The pixel unit with OFF state would cause the light beam  112  to be off the projection lens  120 . After then, the projection lens  120  projects the light beam  112  (image), which has been processed by the light valve  132 , to the screen S. 
   In the embodiment, the beam breaker module  240  is used, so that the projection device having single light valve  200  can be used in various operation modes with high contrast, such as high brightness mode (briefing mode) and the high contrast mode (vide mode). When it needs the image with high brightness, for example, in briefing, the projection device having single light valve  200  can be switched to the high brightness mode. In this mode, the beam breaker module  240  would cut out from the propagation path of the light beam, so as to allow all of the red, green, blue and white light beam  212  to pass, and thereby to have high brightness for the projected image (not shown). In addition, when an image needs high color saturation level and high contrast, such as in viewing the movie, the projection device having single light valve  200  is switched to high contrast mode. In this mode, the beam breaker module  240  would cut in the propagation path of the light beam, so as to break the passing light beam within a specific time period. For example, it breaks the light beam  212  passing through the white filtering region W and the noise light caused by the interfacing region E between the filtering regions. This method can let the image be purely produced by the red light, green light, or blue light, whereby the image color saturation level can be improved, and, even though the brightness of the white image in this mode is reduced, the noise light due to the interfacing region E between the filtering regions can be broken. This can reduce the brightness of the dark image, so that the image contrast can be maintained. The data is shown in the following Table 2 to show the contrast. 
   
     
       
             
             
             
             
           
             
             
             
             
           
         
             
                 
               TABLE 2 
             
             
                 
                 
             
             
                 
               Brightness for 
               Brightness for 
                 
             
             
                 
               white image 
               dark image 
               Contrast 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
               Hight brightness mode 
               1000 (Lux)  
               1 (Lux) 
               1000 
             
             
               High color saturation mode 
               500 (Lux) 
               0.5 (Lux)   
               1000 
             
             
                 
             
           
        
       
     
   
   In summary, the projection device having single light valve of the invention uses a beam breaker module, which can selectively cut in or cut out from the propagation path of the light beam, and can cut in the propagation path of the light beam to break the passing light beam within a specific time period according to the state of the color production device. As a result, it allows the projection device having single light valve to adapt to various operation modes with the consideration of image contrast at the same time. 
   It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.