BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 (Prior Art) illustrates a frame time of a conventional liquid crystal display (LCD);
FIG. 2A shows the structure of a LCD according to a preferred embodiment of the present invention;
FIG. 2B illustrates the structure of the pixel 204 in FIG. 2A;
FIG. 3A illustrates scan sections of the LCD in FIG. 2A;
FIG. 3B illustrates a diagram of the frame time of the LCD in FIG. 3A when the LCD displays a frame;
FIG. 4A illustrates a diagram of time order of the frame time in FIG. 3B;
FIG. 4B illustrates a diagram of another time order of the frame time of the LCD in FIG. 3A; and
FIG. 5 is a flow chart of a driving method according to the preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
A liquid crystal display (LCD) of the present invention inserts a black frame during a frame time a frame displays for solving the double image effect associated with the moving frames. The LCD of the present invention includes a display region divided into several scan sections. Blanking time is distributed to each scan section. Each time all the pixels of one scan section are turned black for inserting the black frame. The LCD of the present invention inserts a black frame without increasing the frame rate.
FIG. 2A shows the structure of the LCD according to one embodiment of the present invention. Each pixel of a display panel 203 is controlled by a scan driver 202 through a scan line and receives data from a data driver 201 through a data line. For example, the pixel 204 of the display panel 203 is controlled by the scan driver 202 through the first scan line S1 and receives the data from the data driver 201 through the data line D1. The rest of the pixels of the display panel 203 are controlled and receive data similarly. The resolution of the preferred embodiment is 1280×1024 as an example. However, the present invention is not limited thereto.
FIG. 2B illustrates the structure of the pixel 204 in FIG. 2A. The pixel 204 includes a transistor 205, a liquid crystal capacitor CLC and a storage capacitor CST. A gate of the transistor 205 is coupled with the first scan line S1. A drain of the transistor 205 is coupled with the data line D1. The liquid crystal capacitor CLC and the storage capacitor CST are connected between a source of the transistor 205 and a common electrode Vcom.
Please referring to FIG. 3A, different sections of the LCD in FIG. 2A are shown in FIG. 3A. The 1024 scan lines of the LCD in FIG. 2A are evenly distributed to 42 scan sections. Each scan section between the first scan section B1 to the 41st scan section B41 has 24 (the integer portion of 1024/42) scan lines. The 42nd scan section has 40 (1024−24×41=40) scan lines. For example, the first scan section B1 includes the first scan line S1 to the 24th scan line S24. The 42nd scan section B42 includes the 985th scan line S985 to the 1024th scan line S1024.
FIG. 3B illustrates the frame time of the LCD in FIG. 3A when the LCD displays a frame. Please referring to FIG. 3B, the LCD displays a frame during the frame time TD. The frame time TD includes 1024 scan-line times TS1˜TS1024 and a blanking time. Each scan line of the display is enabled during one scan-line time. As shown in FIG. 3B, the blanking time is divided into 42 black-frame-inserting times TB1˜TB42 respectively corresponding to the 42 scan line sections B1˜B42. The 1024 scan-line times and the 42 black-frame-inserting times are evenly distributed to the 42 scan-section times. As a result, each time period between the first scan-section time TB1 to the 41st scan-section line period TB41 includes a black-frame-inserting time and 24 (the integer portion of 1024/42) scan-line times. The 42nd scan-section time TB42 includes a black-frame-inserting time and 40 (1024−24×41=40) scan-line times. The length of each scan-line time is the same as that of each black-frame-inserting time. The 24 scan lines of the first scan section B1 to the 41st scan section B41 are enabled during the first scan-section time TB1 to the 41st scan-section time TB41 respectively. The 40 scan lines of the 42nd scan section B42 are enabled during the 42nd scan-section time TB42. The first line time of each scan-section time is the black-frame-inserting time in the present embodiment. However, the black-frame-inserting time can be located in any position during the scan-section time.
All the pixels of the 21st scan section are turned black first in the present embodiment as an example to illustrate the method for inserting a black frame according to the present embodiment. FIG. 4A illustrates time order of the frame time in FIG. 3B. First, during the black-frame-inserting time TI1 of the first scan-section time TB1, the pixels corresponding to all the scan lines of the 21st scan section B21 are turned black. Next, during the first scan-line period TS1 of the first scan-section time TB1, the first scan line S1 is enabled. During the second scan-line time TS2 of the first scan-section time TB1, the second scan line S2 is enabled. Then, other scan lines of the first scan section B1 are enabled during the first scan-section time TB1 similarly. Afterwards, during the black-frame-inserting time TI2 of the second scan-section time TB2, all the pixels corresponding to the scan lines of the 22nd scan section B22 are turned black. Later, the above steps are repeated during the second scan-section time TB2 and not described to avoid redundancy.
During the black-frame-inserting time TI22 of the 22nd scan-section time TB22, all the pixels corresponding to the scan lines of the 42nd scan-section B42 are turned black. Thereon, during the black-frame-inserting time TI23 of the 23rd scan-section time TB23, all the pixels corresponding to the scan lines of the first scan section B1 are turned black. During the black-frame-inserting time TI24 of the 24th scan-section time TB24, all the pixels corresponding to the scan lines of the second scan section B2 are turned black. The following steps during the rest of the black-frame-inserting times are similar to the above ones.
In another embodiment, 24 scan lines are in the first scan section to the 26th scan section. 25 scan lines are in the 27th scan section to the 42nd scan section. Each scan-section time of the first scan-section time to the 26th scan-section time includes 24 scan-line times. Each scan-section time of the 27th scan-section time to the 42nd scan-section time includes 25 scan-line times.
The scan-line times are distributed to all the scan-section times evenly in the embodiment of the present invention. Therefore, all the scan lines in each scan section between the first scan section B1 to the 41st section B41 have the same enabling time. The conventional problem that the enabling time of each scan line is different is resolved, and all the portions of the frame have the same brightness.
In the present embodiment, all the scan lines of the 21st scan section B21 are turned black first as an example. However, pixels in any scan section can be turned black first. For example, in another embodiment, the pixels corresponding to the scan lines in the 11th scan section B11 are turned black first. In other words, during the black-frame-inserting time TI1 of the first scan section time, the pixels corresponding to the scan lines in the 11th scan section B11 are turned black. The actions in the rest of the black-frame-inserting time are similar as those above. The steps of inserting other black frames are similar to those above. In FIG. 4A which shows the time order of the frame time, the black-frame-inserting time of each scan-section time is the first line time of each scan-section time. However, the black-frame-inserting time can be located in any position within each scan-section time.
FIG. 4B illustrates another time order of the frame time of the LCD in FIG. 3A. The LCD displays a frame in a frame time TD. The frame time TD includes 1024 scan-line times TS1˜TS1024 and a blanking time. The 1024 scan-line times TS1˜TS1024 are divided into 42 scan-section times, which respectively correspond to the 42 scan sections B1˜B42 of the display. There is a black-frame-inserting time before each scan-section time. As a result, each scan-section time between the first scan-section time TB1′ to the 41st scan-section time TB41′ has 24 (the integer portion of 1024/42) scan-line times. The 42nd scan-section time TB42′ includes 40 (1024−24×41=40) scan-line times. The first black-frame-inserting time TI1′ is before the first scan-section time TB1′. The second black-frame-inserting time TI2′ is before the second scan-section time TB2′. The rest of the black-frame-inserting times are located similarly.
In FIG. 4B, firstly, during the first black-frame-inserting time TI1′, the pixels corresponding to all the scan lines of the 21st scan section B21 are turned black. Next, during the first scan-line time TS1 of the first scan-section time TB1′, the first scan line of the LCD is enabled. During the second scan-line time TS2 of the first scan-section time TB1′, the second scan line S2 is enabled. Afterwards, the steps during the first scan-section time TB1′ are similar to above ones. Thereon, during the second black-frame-inserting time TI2′, the pixels corresponding to all the scan lines of the 22nd scan section B22 are turned black. Later, the steps during the second scan-section time TB2′ are similar to those in the first scan-section time TB1′ and not described redundantly.
During the 22nd black-frame-inserting time TI22′, the pixels corresponding to all the scan lines of the 42nd scan section B42 are turned black. Then, during the 23rd black-frame-inserting time TI23′, the pixels corresponding to all the scan lines of the first scan section B1 are turned black. During the 24th black-frame-inserting time TI24′, the pixels corresponding to all the scan lines of the second scan section B2 are turned black. Subsequently, the steps during the other black-frame-inserting times are similar to above ones.
In FIG. 4B, each black-frame-inserting time is located before one scan-section time as an example. However, each black-frame-inserting time can be located after one scan-section time. Furthermore, the pixels corresponding to all the scan lines of the 21st scan section B21 are turned black first as an example in the present embodiment. However, the pixels corresponding to any scan section can be turned black first. For example, in another embodiment, the pixels corresponding to all the scan lines of the 11th scan section B11 are turned black first. During the first black-frame-inserting time, all the pixels corresponding to the scan lines of the 11th scan section are turned black. The steps during other black-frame-inserting times are similar to above ones.
The LCD of the present invention is a normally white LCD or a normally black LCD. The LCD includes a scan driver for driving the scan lines of the scan sections. The scan driver includes a first shift register and a second shift register. The first shift register is for controlling the black-frame-inserting times. The second shift register is for controlling the scan-line times. The number of the scan lines in each scan section is not necessarily the same.
FIG. 5 is a flow chart of a driving method according to the embodiment of the present invention. The driving method of the present invention is for a LCD. The LCD includes a display region divided into M scan sections. Each scan section includes several scan lines. The display region displays a frame in a frame time. The frame time is divided into several scan-section times corresponding to the scan sections. Each scan-section time includes a black-frame-inserting time and several scan-line times. First, in step 400, during the black-frame-inserting time of the Sth scan-section time, determine whether (S+N) is greater than M. N is an integer between 1 and M. When it is false, then the method goes to a step 410. When it is true, then the method goes to a step 440. In step 410, the pixels corresponding to all the scan lines of the (S+N)th scan section are turned black. In the step 440, all the pixels of the (S+N-M)th scan section are turned black. Next, in step 420, during the scan-line time of the Sth scan section time, enable the scan lines of the Sth scan section in order. In step 430, it is determined whether the pixels of all the scan sections are all turned black already. When it is true, the method ends. When it is false, the method goes to step 450. In step 450, S is increased by 1. In other words, the above steps are repeated in the next scan-section time until all the pixels of the scan sections are turned black.
For example, in the above mentioned flow chart, M is equal to 42, and N is equal to 20. During the first scan-section time (that is, S is equal to 1), the step 400 is false. Therefore, during the black-frame-inserting time of the first scan-section time, the pixels corresponding to all the scan lines in the 21st scan section are turned black. During the scan-line times of the first scan-section time, the scan lines of the first scan section are enabled. During the 23rd scan-section time, the step 400 is true. In other words, the 21st to the 42nd scan section are turned black already. The first 20 scan sections are needed to be turned black. Therefore, during the black-frame-inserting time of the 23rd scan-section time, the pixels corresponding to all the scan lines of the first scan section are turned black.
The black-frame-inserting time is the first line time of each scan-section time. However, the black-frame-inserting time can be located in any position within each scan-section time.
A black frame is inserted during the blanking time of the frame time when the LCD displays a frame. The display region of the LCD is divided into several scan sections. The blanking time is distributed to each scan section evenly. Each time the pixels in one scan section are turned black for inserting the black frame without increasing the frame rate. The problem of the conventional LCD that the lower portion of the frame is darker than the upper portion is resolved.
While the invention has been described by way of example and in terms of an embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Patent Application
20080012791
