Patent Publication Number: US-2015077443-A1

Title: Three-dimensional display apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a divisional application of and claims the priority benefit of U.S. patent application Ser. No. 13/684,581, filed on Nov. 26, 2012, now allowed. The prior U.S. patent application Ser. No. 13/684,581 is a divisional application of and claims the priority benefit of U.S. patent application Ser. No. 12/496,655, filed on Jul. 02, 2009, now patented. The prior U.S. application Ser. No. 12/496,655 claims the priority benefit of Taiwan application serial no. 98209055, filed on May 22, 2009. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of specification. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention generally relates to a display apparatus; more specifically, to a three-dimensional display apparatus. 
     2. Description of Related Art 
     With recent advancements of display technologies, the research focus has gradually shifted towards devices that can generate three-dimensional (3D) images. 
       FIG. 1A  is an exploded view of a conventional 3D display apparatus. 
     Referring to  FIG. 1A , a conventional 3D display apparatus  100  includes a first panel  110 , a second panel  120  and a cold cathode fluorescent light source  130  (placed in order). Between the first panel  110  and the second panel  120  there is a depth D. 3D image effects are generated due to the image brightness difference between images formed by the first panel  110  and the second panel  120 , coupled with human visual illusion of this scene. Observer P perceives the generated image as if the image is located between the first panel  110  and the second panel  120 . This technology is commonly known as Depth-Fused 3D, or DFD. 
     More specifically, as shown in  FIG. 1A , the image brightness values on the first panel  110  and the second panel  120  are determined by their respective cross-sectional densities. The higher the panel cross-sectional density, the higher the brightness value; conversely, the image brightness value will be lower. Due to the lower image brightness value at a first location A 1  of the first panel  110  with respect to the image brightness value at a second location A 2  of the second panel  120 , the observer P perceives a deeper image there. The perceived image will be located closer to the second panel  120  (farther away from the observer P). Similarly, the image brightness value at a third location A 3  of the first panel  110  is higher than the image brightness value at a fourth location A 4  of the second panel  120 . Therefore, observer P observes a shallower image there, and the perceived image will be located closer to the first panel  110  (closer to the observer P).  FIG. 1B  is a schematic perspective view of the first and second panels of the 3D display found in  FIG. 1A . Referring to  FIG. 1B , the first panel  110  and the second panel  120  each respectively includes a polarizer  111 , 121 , an active device array substrate  113 , 123 , a color filter  115 , 125 , and a substrate  117 , 127 . It should be noted that a light ray L emanating from the cold cathode fluorescent light source  130  travels sequentially through the polarizer  121  of the second panel  120 , the active device array substrate  123 , the color filter  125 , the substrate  127 , the active device array substrate  113  of the first panel  110 , the color filter  115 , the substrate  117 , the polarizer  111 , and then the light ray L enters the eyes of the observer P. 
     The technology aforementioned makes use of two panels (the first panel  110  and the second panel  120 ), where the panel transmittances of the first panel  110  and the second panel  120  are very low, at around 5%. Therefore, brightness value of the light ray L emanating from the cold cathode fluorescent light source  130  will be significantly reduced after the light ray L passes through the first panel  110  and the second panel  120 . In other words, there is a significant difference between the image brightness value the observer P perceives and the original brightness value of the cold cathode fluorescent light source  130 . Hence, when the need to present more brilliant images arises, the cold cathode fluorescent light source  130  must be turned quite bright, hereby significantly increasing the power consumption of the 3D display apparatus  100 . 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides a 3D display apparatus capable of generating quality 3D color images while featuring better panel transmission rate and lower power consumption. 
     The present invention provides a 3D display apparatus including a backlight module, a first panel, a second panel, and a synchronization device. The backlight module has a light emitting side, and the backlight module sequentially emits a plurality of color light. The first panel is disposed at the light emitting side, and the first panel includes a first polarizer and a first liquid crystal substrate. The first polarizer is disposed between the first liquid crystal substrate and the backlight module. The second panel is disposed at the light emitting side, and the first panel is disposed between the backlight module and the second panel. The second panel includes a second liquid crystal substrate and a second polarizer, and the second liquid crystal substrate is disposed between the second polarizer and the first panel. The synchronization device is electrically connected to the backlight module, the first liquid crystal substrate, and the second liquid crystal substrate. During a frame time, the synchronization device synchronously drives the backlight module and the first and second liquid crystal substrates. 
     In one embodiment of the present invention, during the frame time, the synchronization device aforementioned coordinates the color light sequentially emitted by the backlight module with the image information generated by the first and second liquid crystal substrates. 
     In one embodiment of the present invention, during the aforementioned frame time, the synchronization device receives a first driving signal from the backlight module and generates a second driving signal and a third driving signal, sends the second signal to the first liquid crystal substrate, and sends the third driving signal to the second liquid crystal substrate. 
     In one embodiment of the present invention, during the aforementioned frame time, the synchronization device receives a first driving signal from the first liquid crystal substrate and generates a second driving signal and a third driving signal, sends the second driving signal to the backlight module, and sends the third driving signal to the second liquid crystal substrate. 
     In one embodiment of the present invention, during the aforementioned frame time, the synchronization device receives a first driving signal from the second liquid crystal substrate and generates a second driving signal and a third driving signal, sends the second driving signal to the backlight module, and sends the third driving signal to the first liquid crystal substrate. In another embodiment of the invention, during the aforementioned frame time, the synchronization device generates a first, second, and third driving signal and synchronously sends the three signals to the backlight module, the first liquid crystal substrate, and the second liquid crystal substrate, respectively. 
     In one embodiment of the present invention, during the aforementioned frame time, the images generated by the first and second liquid crystal substrates are combined to generate a 3D image. 
     In one embodiment of the present invention, the aforementioned first image and second image have unequal image brightness values. 
     In one embodiment of the present invention, the three-dimensional display apparatus further includes a third liquid crystal substrate disposed between the first and second panels. 
     In one embodiment of the present invention, during the frame time, the aforementioned synchronization device coordinates the color light sequentially emitted by the backlight module with the image information displayed by the first, second, and third liquid crystal substrates. 
     In one embodiment of the present invention, during the aforementioned frame time, the synchronization device receives a first driving signal from the first liquid crystal substrate and generates a second, third, and fourth driving signal, sends the second driving signal to the backlight module, sends the third driving signal to the third liquid crystal substrate, and sends the fourth driving signal to the second liquid crystal substrate. 
     In one embodiment of the present invention, during the aforementioned frame time, the images generated by the first, second, and third liquid crystal substrates are combined to generate a 3D image. 
     In one embodiment of the present invention, the image brightness values of the aforementioned first, second, and third images are all unequal. 
     In one embodiment of the present invention, the aforementioned backlight module includes matrix backlight units; each of backlight units includes one red light-emitting diode (LED), one green LED, and one blue LED. 
     In one embodiment of the present invention, the aforementioned first liquid crystal substrate includes the first active device array substrate, a first opposite substrate, and a first liquid crystal layer. The first active device array substrate includes a plurality of matrix first-pixel units, where each of the first-pixel units corresponds to a plurality of backlight units. The first opposite substrate is disposed opposite to the first active device array substrate. The first liquid crystal layer is disposed between the first active device array substrate and the first opposite substrate. 
     In one embodiment of the present invention, the aforementioned second liquid crystal substrate includes a second active device array substrate, a second opposite substrate, and a second liquid crystal layer. The second active device array substrate includes a plurality of matrix second-pixel units, where each of the second-pixel unit has a plurality of corresponding backlight units. The second opposite substrate is disposed opposite to the second active device array substrate. The second liquid crystal layer is disposed between the second active device array substrate and the second opposite substrate. 
     In one embodiment of the present invention, the polarizing direction of the aforementioned first polarizer is substantially perpendicular to the polarizing direction of the aforementioned second polarizer. 
     Based on the above, the 3D display apparatus of the present invention is spared of the poorly transmissive color filters. The 3D display apparatus also replaces the conventional cold cathode fluorescent light source with a backlight module that sequentially emits a plurality of color light. Therefore, the 3D display apparatus of the present invention possesses a higher transmission rate. Furthermore, the 3D display apparatus also includes a synchronization device which, during a frame time, synchronizes the driving of the backlight module and the first and second panels such that the emitted color light from the backlight module can be coordinated with the image information generated by the first and second panels. Consequently, quality color 3D images are generated. 
    
    
     
       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. 1A  is an exploded view of the conventional 3D display apparatus. 
         FIG. 1B  is a schematic perspective view of the first and second panel of the 3D display apparatus in  FIG. 1A . 
         FIG. 2  is an exploded view of an embodiment of the 3D display apparatus of the present invention. 
         FIG. 3  to  FIG. 6  are schematic views that show the driving schemes between components of the 3D display apparatus in  FIG. 2 . 
         FIG. 7  is an exploded view of another embodiment of the 3D display apparatus of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 2  is an exploded view of an embodiment of the 3D display apparatus of the present invention.  FIG. 3  to  FIG. 6  are schematic views that show the driving schemes between components of the 3D display apparatus in  FIG. 2 . In  FIG. 3  to  FIG. 6 , only the backlight module  210 , the first liquid crystal substrate  250 , the second liquid crystal substrate  260 , and the synchronization device  280  of the 3D display apparatus  200  are drawn in order to show the driving schemes between each component. 
     Following,  FIG. 2  and  FIG. 3  are referenced to explain how the 3D display apparatus  200  is built. Referring to  FIG. 2  and  FIG. 3 , this 3D display apparatus  200  includes the backlight module  210 , the first panel  220 , the second panel  230 , and the synchronization device  280 . The backlight module  210  has a light emitting side B, and the backlight module  210  sequentially emits a plurality of color light (not drawn). 
     The first panel  220  is disposed in the light emitting side B, and the first panel  220  includes a first polarizer  240  and a first liquid crystal substrate  250 ; the first polarizer  240  is disposed between the first liquid crystal substrate  250  and the backlight module  210 . The second panel  230  is disposed in the light emitting side B; the first panel  220  is disposed between the backlight module  210  and the second panel  230 . The second panel  230  includes a second liquid crystal substrate  260  and a second polarizer  270 ; the second liquid substrate  260  is disposed between the second polarizer  270  and the first panel  220 . The synchronization device  280  is electrically connected to the backlight module  210 , the first liquid crystal substrate  250 , and the second liquid crystal substrate  260 . During a frame time, the backlight module  210 , the first liquid crystal layer  250 , and the second liquid crystal layer  260  are synchronously driven by the synchronization device  280 . 
     Continuing reference to  FIG. 2 , the backlight module  210  may include matrix backlight units  212 ; each of the backlight units  212  includes one red LED  212   a,  one green LED  212   b,  and one blue LED  212   c.  Hence, the backlight module  210  can sequentially emit red, green, and blue light (not drawn). In particular, in the short span of human visual retention, the rapid switching of red, green, and blue light emitted from the red LED  212   a,  the green LED  212   b,  and the blue LED  212   c,  respectively, results in a color mixing effect. This technique is called the Color Sequential Method. 
     Therefore, the 3D display apparatus  200  of the present invention can omit the use of color filters. However, the present invention does not limit the model of the backlight module  210 ; any backlight module capable of sequentially emitting a plurality of color light is within the scope of the present invention. 
     Referring to  FIG. 2 , the first liquid crystal substrate  250  includes a first active device array substrate  252 , a first opposite substrate  254 , and a first liquid crystal layer  256 . The first active device array substrate  252  includes matrix first-pixel units  252   a ; each of the first-pixel unit  252   a  corresponds to backlight units  212 . The first opposite substrate  254  is disposed opposite to the first active device array substrate  252 . The liquid crystal layer  256  is disposed between the active device array substrate  252  and the opposite substrate  254 . 
     Similarly, the second liquid crystal substrate  260  includes a second active device array substrate  262 , a second opposite substrate  264 , and a second liquid crystal layer  266 . The second active device array substrate  262  includes matrix second-pixel units  262   a;  each of the second-pixel units  262   a  corresponds to backlight units  212 . The second opposite substrate  264  is disposed opposite to the second active device array substrate  262 . The second liquid crystal layer  266  is disposed between the active device array substrate  262  and the second opposite substrate  264 . 
     In addition, the 3D display apparatus  200  of the present invention needs only one set of polarizers, namely the first polarizer  240  and the second polarizer  270  in order to generate quality images. The first polarizer  240  is disposed between the backlight module  210  and the first panel  220 ; the second polarizer  270  is disposed at a side of the second panel  230  away from the first panel  220 . In particular, the polarizing direction of the first polarizer  240  is substantially perpendicular to the polarizing direction of the second polarizer  270 . 
     As shown above, one of the features of the 3D display apparatus  200  of the present invention includes the omission of color filters, thereby improving panel transmission rate of the first panel  220  and the second panel 230 by around 15%. Color images are generated by direct application of the plurality of color light (not drawn) provided by the backlight module  210  of the present invention, in combination with the Color Sequential Method for mixing the emitted color light. By also applying the DFD technique on the first panel  220  and the second panel  230 , high resolution color 3D images are generated. 
     In more detail, if for basis of calculation the acceptable image brightness value for observer P is 200 nits, and the panel transmission rate of the first panel  110  and the second panel  120  of the conventional 3D display apparatus  100  in  FIG. 1A  and FIG. 1B is 5%, then the required brightness value from the cold cathode fluorescent light source  130  is: 
       200 (nits)/(5%*5%)=80,000 (nits) 
     However, the panel transmission rate of the first panel  220  and the second panel  230  of the 3D display apparatus  200  is improved to 15%, so in actuality, the required brightness from the backlight module  210  is only: 
       200 (nits)/(15%*15%)=8,888 (nits) 
     In light of the above-mentioned, the actual brightness required (8,888 nits) from the backlight module  210  of the present invention is about one tenth of the brightness required (80,000 nits) from the conventional cold cathode fluorescent light source  130 . Therefore, there are drastic savings with brightness loss and power consumption to be gained from the backlight module  210 . 
     As shown in  FIG. 3 , during the frame of time, a first image E 1 , generated by the first liquid crystal substrate  250 , and a second image E 2 , generated by the second liquid crystal substrate  260 , are combined to form one 3D image E 3 . In particular, because the brightness of the first image E 1  is not equal to the brightness of the second image E 2 , the 3D image E 3  is generated by the DFD technique. 
     It should be noted that another feature of the 3D display apparatus  200  of the present invention is that, during the frame time, the synchronization device  280  coordinates color light sequentially emitted from the backlight module  210  with the image information generated by the first liquid crystal substrate  250  and the second liquid crystal substrate  260 . In other words, with the control of the synchronization device  280 , this 3D display apparatus  200  can generate quality color 3D images and consequently, avoid problems of untrue colors and unsuccessful generations of 3D images. 
     As shown in  FIG. 3 , during the frame time, the synchronization device  280  receives a first driving signal S 1  from the backlight module  210  and generates a second driving signal S 2  and a third driving signal S 3 , sends the second driving signal S 2  to the first liquid crystal substrate  250 , and sends the third driving signal S 3  to the second liquid crystal substrate  260 . At this time, the backlight module  210  is the actively driven device; the first liquid crystal substrate  250  and the second liquid crystal substrate  260  are passively driven devices. 
     However, the active/passive driving schemes between the backlight module  210 , the first liquid crystal substrate  250 , and the second liquid crystal substrate  260  are not limited to what is shown in  FIG. 3 . For example, alternate driving schemes may be found in  FIG. 4  to  FIG. 6 . 
     Referring to  FIG. 4 , during the frame time, the synchronization device  280  receives a first driving signal H 1  from the first liquid crystal substrate  250  and generates a second driving signal H 2  and a third driving signal H 3 , sends the second driving signal H 2  to the backlight module  210 , and sends the third driving signal H 3  to the second liquid crystal substrate  260 . At this time, the first liquid crystal substrate  250  is the actively driven device; the backlight module  210  and the second liquid crystal substrate  260  are passively driven devices. 
     Referring to  FIG. 5 , during the frame time, the synchronization device  280  receives a first driving signal L 1  from the second liquid crystal substrate  260  and generates the second driving signal L 2  and the third driving signal L 3 , sends the second driving signal L 2  to the backlight module  210 , and sends the third driving signal L 3  to the first liquid crystal substrate  250 . At this time, the second liquid crystal substrate  260  is the actively driven device; the backlight module  210  and the first liquid crystal substrate  250  are passively driven devices. 
     During the frame time,  FIG. 6  shows that the synchronization device  280  can synchronously generate a first driving signal T 1 , a second driving signal T 2 , and a third driving signal T 3  and send the signals to the backlight module  210 , the first liquid crystal substrate  250 , and the second liquid crystal board  260 , respectively. At this time, the synchronization device  280  is the actively driven device; the backlight module  210 , the first liquid crystal substrate  250  and the second liquid crystal substrate  260  are the passively driven devices. Based on the above, any driving schemes capable of coordinating the driving of the backlight module  210 , the first liquid crystal substrate  250 , and the second liquid crystal substrate  260  is within the realm of this invention. 
       FIG. 7  is an exploded view of another embodiment of the 3D display apparatus of the present invention. Referring to  FIG. 7 , the same components are given the same numbering. Different from the aforementioned 3D display apparatus  200  in  FIG. 2  and  FIG. 3 , this 3D display apparatus  300  includes an additional third liquid crystal substrate  310  disposed between the first liquid crystal substrate  250  and the second liquid crystal substrate  260 . In other words, more than two liquid crystal substrates can be used to generate color 3D images. 
     As shown in the embodiment of  FIG. 7 , during the frame time, the synchronization device  280  coordinates color light sequentially emitted from the backlight module  210  with the image information displayed by the first liquid crystal substrate  250 , the second liquid crystal substrate  260 , and the third liquid crystal substrate  310 . 
     More specifically, during the frame time, the first image F 1  generated by the first liquid crystal substrate  250 , the second image F 2  generated by the second liquid crystal substrate  260 , and the third image F 3  generated by the third liquid crystal substrate  310  can be combined to generate a 3D image F 4 . In particular, due to the brightness difference between the first image F 1 , the second image F 2 , and the third image F 3 , the DFD technique can be applied to generate a 3D image F 4 . Here, the present invention does not set any limitations on the number of liquid crystal substrates, and therefore the designer has the option to change the number of substrates based on the desired depth of the 3D images. 
     To illustrate further, an example of the driving scheme between each component of this 3D display apparatus  300  is as follows. During the frame time, the synchronization device  280  receives a first driving signal J 1  from the first liquid crystal substrate  250  and generates a second driving signal J 2 , a third driving signal J 3 , and a fourth driving signal J 4 , sends the second driving signal J 2  to the backlight module  210 , sends the third driving signal J 3  to the third liquid crystal substrate  310 , and sends the fourth driving signal J 4  to the second liquid crystal substrate  260 . Here, the present invention does not set any limitations on the active/passive driving schemes between the backlight module  210  and the liquid crystal substrates  250 ,  260 , and  310 . 
     In summary, the 3D display apparatus in the present invention has at least the following advantages: 
     This 3D display apparatus avoids the use of color filters, placed by a backlight module that sequentially emits a plurality of color light for the display of color images, and such arrangement results in the increase of the panel transmission rate. 
     Consequently, brightness degradation is minimized and power consumption of the backlight module is decreased. In addition, problems such as untrue colors and unsuccessful generations of 3D images are avoided with the application of the synchronization device. During the frame time, the synchronization device synchronously drives the backlight module along with a plurality of liquid crystal substrates, coordinating color light sequentially emitted from the backlight module with the image information generated by the liquid crystal substrates. 
     Although the invention has been described with reference to the embodiments thereof, it will be apparent to one of the ordinary skills in the art that modifications to the described embodiments may be made without departing from the spirit of the invention. Accordingly, the scope of the invention will be defined by the attached claims not by the above detailed description.