Patent Publication Number: US-8970568-B2

Title: Display device and control method thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority of Taiwan Patent Application No. 101118661, filed on May 25, 2012, the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a display device, and more particularly to a display device comprising a timing controller. 
     2. Description of the Related Art 
     Because cathode ray tubes (CRTs) are inexpensive and provide high definition, they are utilized extensively in televisions and computers. With technological development, new flat-panel displays are continually being developed. When a larger display panel is required, the weight of the flat-panel display does not substantially change when compared to CRT displays. 
     With an increase in the resolution of the display panel, an amount of image data required by the display panel is increased. To access the image data, a conventional method increases the number and bandwidth of memory. Thus, the cost of the flat-panel display is increased. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with an embodiment, a display device comprises a display panel and a timing controller. The display panel displays a first image according to a first output image. The timing controller comprises a receiving unit, a compression unit, a decompression unit and a processing unit. The receiving unit receives a first input image and a second input image and outputs a first processed image and a second processed image. The first input image is the same as the first processed image. The second input image is the same as the second processed image. The compression unit generates a first compressed image according to the first processed image. The receiving unit stores the first compressed image. The decompression unit processes the first compressed image stored in the receiving unit to generate a first decompressed image. The processing unit processes the second processed image and the first decompressed image to generate the first output image. 
     A control method for a display device is provided. An exemplary embodiment of a control method for a display device is described in the following. A first input image and a second input image are received. A first processed image and a second processed image are provided according to the first and the second input images. The first processed image is the same as the first input image. The second processed image is the same as the second input image. A first compressed image is generated according to the first processed image. The first compressed image is stored. The stored first compressed image is decompressed to generate a first decompressed image. The second processed image and the first decompressed image are processed to generate a first output image. The first output image is provided to the display device to display a first image. 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by referring to the following detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a schematic diagram of an exemplary embodiment of a display device; 
         FIGS. 2-4  are schematic diagrams of other exemplary embodiments of a timing controller; 
         FIG. 5  is a schematic diagram of an exemplary embodiment of a control method; and 
         FIG. 6  is a schematic diagram of an exemplary embodiment of step S 502 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
       FIG. 1  is a schematic diagram of an exemplary embodiment of a display device. The display device  100  comprises a display panel  101  and a timing controller (TCON)  102 . The invention does not limit the kind of the display device  100 . In one embodiment, the display device  100  is a personal digital assistant (PDA), a cellular phone, a digital camera (DSC), a television, a global positioning system (GPS), a car display, an avionics display, a digital photo frame, a notebook computer (NB), or a personal computer (PC). 
     The display panel  101  receives an output image S DATA  provided by the timing controller  102  via a flexible printed circuit (FPC)  103  and displays a corresponding image according to the output image S DATA . The invention does not limit the kind and the resolution of the display panel  101 . In one embodiment, the display panel  101  is a self-luminescent panel or a reflective panel. In another embodiment, the display panel  101  is a quad full high definition (QFHS) panel and the resolution of the display panel  101  is 3840×2160. 
     In this embodiment, the display panel  101  comprises scan groups  110  and  120 , a data group  130  and a display region  160 , but the disclosure is not limited thereto. In other embodiments, any circuit structure can be applied in the display panel  101 , as long as the circuit structure is capable of displaying an image in the display region  160 . 
     As shown in  FIG. 1 , the scan group  110  is placed on the left hand side of the display region  160  and comprises gate drivers  111 ˜ 114 . The scan group  120  is placed on the right hand side of the display region  160  and comprises gate drivers  115 ˜ 118 . The gate drivers  111 ˜ 118  provide a plurality of scan signals to pixels in the display region  160 . The invention does not limit the number and the position of the scan groups. In one embodiment, the display panel  101  only comprises a single scan group and is placed on any side of the display region  160 . In another embodiment, the number of the gate drivers is proportional to the number of the pixels in the display region  160 . 
     In this embodiment, the data group  130  comprises source drivers  131 ˜ 154  to provide a plurality of data signals to the pixels in the display region  160 . The invention does not limit the number of the source drivers. In one embodiment, the number of the source drivers relates to the number of the pixels in the display region  160 . 
     The timing controller  102  generates the output image S DATA  to the display panel  101  according to an input image S I . The invention does not limit the format of the input image S I . In one embodiment, the input image S I  is in a low voltage differential signaling (LVDS) format. 
     For clarity, only three input images S I1 ˜S I3  and three output images S DATA1 ˜S DATA3  are shown and taken as an example to describe the operation of the timing controller  102 .  FIG. 2  is a schematic diagram of an exemplary embodiment of a timing controller. In this embodiment, the timing controller  102  comprises a receiving unit  201 , a compression unit  202 , a decompression unit  203  and a processing unit  204 . 
     The receiving unit  201  generates processed images S P1 ˜S P3  according to the input images S I1 ˜S I3 . The invention does not limit how the receiving unit  201  generates the processed images S P1 ˜S P3 . In this embodiment, the receiving unit  201  comprises a storage module  205  to store the input images S I1 ˜S I3 . The storage module  205  acquires stored data according to an access signal (not shown) and serves the acquired data as a processed image (e.g. one of the processed images S P1 ˜S P3 ) for the compression unit  202 . In one embodiment, the storage module  205  comprises a dynamic random access memory (DRAM). 
     The compression unit  202  compresses the processed images S P1 ˜S P3  to generate compressed images S PC1 ˜S PC3  and stores the compressed images S PC1 ˜S PC3  to the receiving unit  201 . The decompression unit  203  decompresses the compressed images S PC1 ˜S PC3  stored in the receiving unit  201  to generate decompressed images S PCD1 ˜S PCD3 . In this embodiment, the decompressed image S PCD1  is the same as the input image S I1 , the decompressed image S PCD2  is the same as the input image S I2 , and the decompressed image S PCD3  is the same as the input image S I3 . 
     The processing unit  204  reads and processes the processed images S P1 ˜S P3  provided by the receiving unit  201  to generate output images S DATA1 ˜S DATA3 . The display panel  101  displays three images according to the output images S DATA1 ˜S DATA3 . The invention does not limit how the processing unit  204  processes the processed images S P1 ˜S P3  provided by the receiving unit  201 . In one embodiment, the processing unit  204  processes the processed image S P1  and a first previous image according to an overdriving (OD) procedure to generate the output image S DATA1 , processes the processed image S P2  and a second previous image according to the OD to generate the output image S DATA2 , and processes the processed image S P3  and a third previous image according to the OD procedure to generate the output image S DATA3 . 
     For example, during a first period, the receiving unit  201  receives and stores the input image S I1 . The processing unit  204  reads the input image S I1  stored in the receiving unit  201 , wherein the read result is served as a processed image S P1 . The processing unit  204  processes the processed image S P1  and a decompressed image S PCD0  to generate an output image S DATA1  according to the OD procedure. The display panel  101  displays a first image according to the output image S DATA1 . 
     In one embodiment, the OD procedure requires two images, but no image occurs before the input image S I1 . Thus, the decompression unit  203  decompresses a pre-determined image S PC0  stored in the storage module  205  and provides the decompressed result (i.e. S PCD0 ) to the processing unit  204 . In another embodiment, since no image occurs before the input image S I1 , the processing unit  204  does not execute the OD procedure for the processed image S P1 . 
     When the processing unit  204  processes the processed image S P1 , the compression unit  202  compresses a data segment, which was processed by the processing unit  204  and stores the compressed result to the storage module  205 . Thus, after the processing unit  204  finishes the OD procedure, the compression unit  202  also finishes a compression action for the processed image S P1 . Additionally, since the compressed image S PC1  replaces the input image S I1  stored in the storage module  205 , the bandwidth of the storage module  205  can be reduced and the usable space of the storage module  205  is increased. 
     During a second period, the receiving unit  201  receives and stores the input image S I2 . The processing unit  204  reads the input image S I2  stored in the receiving unit  201 , wherein the read result is served as a processed image S P2 . To execute the OD procedure, the decompression unit  203  reads and decompresses the compressed image S PC1  stored in the storage unit  205  to generate a decompressed image S PCD1 . In one embodiment, the decompressed image S PCD1  is the same as the input image S I1 . 
     The processing unit  204  processes the processed image S P2  and the decompressed image S PCD1  to generate an output image S DATA2  according to the OD procedure. The display panel  101  displays a second image according to the output image S DATA2 . In this embodiment, when the processing unit  204  processes the processed image S P2 , the compression unit  202  compresses a data segment, which was processed by the processing unit  204  and stores the compressed result to the storage module  205 . Thus, after the processing unit  204  finishes the OD procedure, the compression unit  202  also finishes a compression action for the processed image S P2  and generates the compressed image S PC2 . The compressed image S PC2  replaces the input image S I2  stored in the storage module  205 . 
     During a third period, the receiving unit  201  receives and stores the input image S I3 . The processing unit  204  reads the input image S I3  stored in the receiving unit  201 , wherein the read result is served as a processed image S P3 . The decompression unit  203  reads and decompresses the compressed image S PC2  stored in the storage unit  205  to generate a decompressed image S PCD2 . In one embodiment, the decompressed image S PCD2  is the same as the input image S I2 . 
     The processing unit  204  processes the processed image S P3  and the decompressed image S PCD2  to generate an output image S DATA3  according to the OD procedure. The display panel  101  displays a third image according to the output image S DATA3 . When the processing unit  204  processes the processed image S P3 , the compression unit  202  compresses a data segment, which was processed by the processing unit  204  and stores the compressed result to the storage module  205 . Thus, after the processing unit  204  finishes the OD procedure, the compression unit  202  also finishes a compression action for the processed image S P3  and generates the compressed image S PC3 . The compressed image S PC3  replaces the input image S I3  stored in the storage module  205 . 
     In this embodiment, since the processing unit  204  executes the OD procedure for two images, a response speed of the display panel  101  is quick. Furthermore, since the OD procedure does not require the previous image to have high completeness, when the compression unit  202  compresses the previous image and stores the compressed result to the storage module  205 , the OD efficiency can be maintained and the bandwidth of the storage module  205  can be reduced. 
       FIG. 3  is a schematic diagram of another exemplary embodiment of the timing controller.  FIG. 3  is similar to  FIG. 2  except for the addition of an adjustment unit  306 . Since the receiving unit  301 , the compression unit  302 , the decompression unit  303  and the processing unit  304  are the same as the receiving unit  201 , the compression unit  202 , the decompression unit  203  and the processing unit  204 , the descriptions of the receiving unit  301 , the compression unit  302 , the decompression unit  303  and the processing unit  304  are omitted for brevity. 
     In this embodiment, the adjustment unit  306  adjusts the processed images S P1 ˜S P3  to generate adjusted data S A1 ˜S A3  according to reference values S REF1 ˜S REF3 . The compression unit  302  compresses the adjusted data S A1 ˜S A3  to generate compressed images S AC1 ˜S AC3  and stores the compressed images S AC1 ˜S AC3  to the receiving unit  301 . The decompression unit  303  reads and decompresses the compressed images S AC1 ˜S AC3  stored in the receiving unit  301  to generate decompressed images S ACD1 ˜S ACD3 . 
     The invention does not limit the source of the reference values S REF1 ˜S REF3 . In one embodiment, the reference values S REF1 ˜S REF3  are pre-determined. In another embodiment, the reference values S REF1 ˜S REF3  are decompressed images. For example, each of the reference values S REF1 ˜S REF3  is a previous image. 
     The adjustment unit  306  adjusts a present image according to a previous image. In this embodiment, the decompressed image S ACD1  is served as a previous image and the same as the input image S I1 . For example, the adjustment unit  306  adjusts the processed image S P2  served as a present image according to the decompressed image S ACD1  served as a previous image and provides the adjusted result to the compression unit  302 . 
     Similarly, the adjustment unit  306  adjusts the processed image S P3  served as a present image according to the decompressed image S ACD2  served as a previous image and provides the adjusted result to the compression unit  302 . The invention does not limit how the adjustment unit  306  adjusts the processed images S P1 ˜S P3 . In one embodiment, the adjustment unit  306  processes the reference value S REF1  and the processed image S P1  to generate the adjusted data S A1  according to the OD procedure, processes the reference value S REF2  and the processed image S P2  to generate the adjusted data S A2  according to the OD procedure, and processes the reference value S REF3  and the processed image S P3  to generate the adjusted data S A3  according to the OD procedure. 
       FIG. 4  is a schematic diagram of another exemplary embodiment of the timing controller.  FIG. 4  is similar to  FIG. 3  with the exception that the receiving unit  401  comprises a compression module  407 , a storage module  408  and a decompression unit  409 . 
     The compression module  407  compresses the input images S I1 ˜S I3  to generate compressed images S C1 ˜S C3 . The invention does not limit the compression rates of the compression module  407  and the compression unit  202  or  302 . In one embodiment, the compression rate of the compression module  407  is higher than, less than or equal to the compression rate of the compression unit  202  or  302 . 
     The storage module  408  stores the compressed images S C1 ˜S C3 . In this embodiment, the storage module  408  further stores the compressed images S AC1 ˜S AC3  generated by the compression unit  402 . Since the storage module  408  stores the compressed images, the bandwidth of the storage module  408  can be reduced. 
     The decompression module  409  decompresses the compressed images S C1 ˜S C3  stored in the storage module  408  to generate decompressed images S DC1 ˜S DC3 , serves the decompressed images S DC1 ˜S DC3  as the processed images S P1 ˜S P3  and provides the processed images S P1 ˜S P3  to the processing unit  404 . In one embodiment, the processed image S P1  is the same as the input image S I1 , the processed image S P2  is the same as the input image S I2 , and the processed image S P3  is the same as the input image S I3 . 
       FIG. 5  is a schematic diagram of an exemplary embodiment of a control method. The control method is applied for a display device to display an image. First, a first input image and a second input image are received (step S 501 ). The invention does not limit the format of the first and the second input images. In one embodiment, the first and the second input images are in an LVDS format. 
     A first processed image and a second processed image are provided according to the first and the second input images (step S 502 ). In this embodiment, the first processed image is the same as the first input image, and the second processed image is the same as the second input image. The invention does not limit how the first and the second processed images are provided according to the first and the second input images. In one embodiment, the first and the second input images are stored and served as the first and the second processed images. 
       FIG. 6  is a schematic diagram of an exemplary embodiment of step S 502 . First, the first and the second input images are compressed to generate a first compressed image and a second compressed image (step S 601 ). Thee first and the second compressed images are stored in a memory (step S 602 ). Since the stored images are compressed, the memory does not consume more storage space to store the images. Thus, the bandwidth of the memory is reduced. 
     The first and the second compressed images stored in the memory are decompressed to generate a first decompressed image and a second decompressed image (step S 603 ). The first and the second decompressed images are served as the first and the second processed images, respectively (step S 604 ). 
     Refer to  FIG. 5 , step S 503  generates a first compressed image according to the first processed image. In this embodiment, step S 503  directly compresses the first processed image. In other embodiments, the first processed image is adjusted according to a reference value and the adjusted result is compressed to generate a first compressed image. Additionally, the invention does not limit the compression rates of steps S 503  and S 601 . For example, the compression rate of step S 503  is less than, higher than, or equal to the compression rate of step S 601 . 
     In other embodiments, the first compressed image in step S 503  is the same as or different from the first compressed image in step S 601 . Furthermore, the first processed image is processed according to an OD procedure and then compressed to generate the first compressed image. 
     The first compressed image is stored (step S 504 ). In one embodiment, a memory (e.g. DRAM) is utilized to store the first compressed image. In other embodiments, other storage medium is utilized to store the first compressed image. Additionally, the first and the second input images in step S 501  or the first and the second compressed images in step S 602  is stored in the DRAM. 
     The first compressed image is decompressed to generate a first decompressed image (step S 505 ). The invention does not limit the decompression rates of steps S 505  and S 603 . In one embodiment, the decompression rates of steps S 505  and S 603  are the same. 
     The second processed image and the first decompressed image are processed to generate a first output image (step S 506 ) and then the first output image is provided to the display device to display an image (step S 507 ). The invention does not limit the kind of the display device. In one embodiment, the display device has a self-luminescent panel or a reflective panel. 
     Additionally, in one embodiment, step S 506  is to process the second processed image and the first decompressed image according to an OD procedure, but the disclosure is not limited thereto. In other embodiments, the second processed image and the first decompressed image are processed according to other image procedures. 
     Furthermore, assume the display device is required to display another image. The second processed image is compressed and the compressed result is stored in the DRAM to replace the stored second processed image. 
     Next, a third input image is received. A third processed image is generated according to the third input image. At this time, the compressed result stored in the DRAM is decompressed and the decompressed result and the third processed image are processed to generate a second output image according to the OD procedure. The display device displays another image according to the second output image. 
     In other embodiment, before compressing the second processed image, the second processed image is adjusted to generate adjusted data according to a reference value. Then the adjusted data is compressed. The invention does not limit the source of the reference value. In one embodiment, the reference value is the first decompressed image. 
     In addition, the invention does not limit how the second processed image is adjusted according to a reference value. In one embodiment, the reference value and the second processed image are processed according to an OD procedure and the processed result is served as adjusted data. 
     In summary, since the previous image is compressed, the display device does not require a memory with large storage space and the bandwidth of the memory can be reduced. Furthermore, after decompressing an image, the decompressed result (i.e. the previous image) and the present image are processed according to the OD procedure such that the display device speedily displays images. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.