CN101308632A - Liquid crystal display and driving method - Google Patents

Abstract

A liquid crystal display, used to display one frame in one frame period, including M scanning areas, each scanning area including multiple scanning lines, and each scanning line corresponding to one pixel. Among them, the frame period includes M scanning area periods, corresponding to each scanning area respectively, and the scanning area period of each scanning area includes a black line insertion period and multiple scanning line periods. When the black line insertion period of the S scanning area period among the M scanning area periods, the pixels corresponding to the scanning lines of the (S+N) scanning areas of these scanning areas are all turned to a dark state, and when the scanning line period of the S scanning area period, the scanning lines of the S scanning area are enabled. S is a positive integer less than or equal to M.

Description

Liquid crystal display and driving method

technical field

The present invention relates to a liquid crystal display, and in particular to a liquid crystal display in which a display area of the liquid crystal display is partitioned to insert a black frame in a frame period of a display frame.

Background technique

With the maturity of optoelectronic technology and semiconductor manufacturing technology in recent years, flat panel displays (FlatPanel Display) have flourished, and liquid crystal displays have gradually replaced traditional displays based on their advantages of low voltage operation, no radiation scattering, light weight and small size. The cathode ray tube display has become the mainstream of display products in recent years.

The liquid crystal display mainly includes a liquid crystal display panel (liquid crystal display panel) and a backlight module, wherein the liquid crystal display panel is composed of a color filter substrate (Color Filter substrate, C/F substrate), a thin film transistor array substrate (Thin Film Transistor array substrate, TFT array substrate ) and a liquid crystal layer arranged between the two substrates, and the backlight module is used to provide the surface light source required by the liquid crystal display panel, so that the liquid crystal display can achieve the display effect. Moreover, a plurality of pixel electrodes are disposed on the thin film transistor array substrate, wherein the pixel electrodes can be used to control the rotation of liquid crystal molecules in the liquid crystal display panel to determine the passing amount of light.

When human eyes watch the dynamic images played on the LCD monitor, each digital frame will stay on the display screen for a period of time before changing to the next frame. At this time, the moving objects in the front and rear frames of the digital image do not move continuously display, but in the manner of moving at intervals. However, when the human eye looks at a moving object, it will track the moving position of the object, and the backlight module continues to provide surface light during the frame change process of the liquid crystal display. Therefore, it is easy for the human eye to detect that the object does not move continuously during the frame conversion process (that is, the liquid crystal molecule rotation process), and because the same moving object stays in different positions on the retina in the previous and subsequent frames of the image, smearing occurs. (double image) phenomenon and lead to blurring of the image outline, further adversely affecting the display quality of the liquid crystal display.

In order to solve the above problems, the traditional liquid crystal display has developed the technology of inserting black frames, inserting a completely black frame between two frames, so that the human eye cannot feel the dragging phenomenon between frames, and effectively solves the afterimage problem.

However, traditional liquid crystal displays insert black frames between two frames, which halves the time for each pixel to display a frame, and each pixel turns into a dark state for the other half of the time, which is equivalent to increasing the frame update rate (frame rate) Doubling, so that the time for each pixel to charge to the predetermined value is too short, so that each pixel cannot be charged to the predetermined value within the predetermined time, and an error occurs in the display frame.

Another conventional liquid crystal display is to insert a black frame in the blanking time of the frame period of the scanning frame. FIG. 1 shows a schematic diagram of a frame period of a conventional liquid crystal display screen. In FIG. 1 , for an LCD with 1024 scanning lines, its frame period TF includes 1066 line periods, of which 1024 line periods are scanning line periods, and the other 42 line periods are blank periods T _blank . Each scan line is enabled in each scan line period, for example, in the first scan line period TS1, the first scan line is enabled. When all 1024 scan line periods are over, all pixels of the liquid crystal display are turned into a dark state during a blank period T _blank , that is, after the 1024th scan line is enabled, all pixels are turned into a dark state. Therefore, the display time of the pixels in the 1024th column is the shortest, and the display time of the pixels in the first column is the longest, and the display time of the pixels in each column is not equal, resulting in the lower half of the frame being darker than the upper half.

Contents of the invention

In view of this, the object of the present invention is to provide a driving method for driving a liquid crystal display. The liquid crystal display of the present invention inserts a black frame within the frame time of the display frame, which can effectively solve the problem of afterimages caused by fast dynamic frame changes. The display area of the liquid crystal display of the present invention is divided into several scanning areas, the blank period is allocated to each scanning area, and all the pixels in the scanning area are turned into a dark state in the predetermined scanning time, so as to realize the purpose of inserting black frames, and can Solve the aforementioned problem of inconsistency in the brightness of the upper and lower half of the frame of the traditional liquid crystal display. The liquid crystal display proposed by the present invention can insert black frames within the frame time without increasing the frame update rate. However, those skilled in the art can know that the technique of increasing the frame update rate can also be combined to realize the driving method of the present invention.

According to the object of the present invention, a liquid crystal display is proposed to display a frame in a frame period, including M scanning areas, each scanning area includes several scanning lines, each scanning line corresponds to a column of pixels, and M is a positive integer. Wherein, the frame period includes M scanning area periods, respectively corresponding to each scanning area, and the scanning area period of each scanning area includes a plurality of line periods, and these line periods include a black line insertion period and a plurality of scanning line periods. When the black line insertion period of the S scan area period in the M scan area periods, the pixels corresponding to the scan lines of the (S+N) scan area of these scan areas are all turned into a dark state. In the scan line period of the scan area period, the scan lines of the S-th scan area are enabled. S is a positive integer less than or equal to M, and N is a positive integer less than or equal to M.

According to the purpose of the present invention, a kind of driving method is proposed, used in the display, the display has a display area, the display area is divided into M scanning areas, each scanning area includes several scanning lines, and the period of displaying a frame in the display area is a frame Period, the frame period is divided into M scan area periods, corresponding to M scan areas, each scan area period includes a plurality of line periods, the line period includes a black line insertion period and a plurality of scan line periods, the method includes: In the black line inserting period of the S-th scanning area period, the pixels corresponding to the scanning lines of the (S+N)-th scanning area are turned into a dark state. Then, during the scan line period of the S-th scan zone period, the scan lines of the S-th scan zone are enabled. Wherein, M is a positive integer, S is a positive integer less than or equal to M, and N is a positive integer less than or equal to M.

According to the purpose of the present invention, a driving method is proposed to drive a display with frame data, and the display includes a first scanning area and a second scanning area. The driving method includes: driving the second scanning area to a dark state during the first black line insertion period. Afterwards, during the period of the first scanning area, the first scanning area is driven with the first part of the frame data. The first scanning area is driven to a dark state during the second black line insertion period. Finally, during the period of the second scanning area, the second scanning area is driven with the second part of the frame data.

In order to make the above-mentioned objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 shows a schematic diagram of a frame period of a traditional liquid crystal display screen;

Fig. 2A shows the structural diagram of the liquid crystal display of the embodiment of the present invention;

FIG. 2B shows a block diagram of the pixel 204 of FIG. 2A;

FIG. 3A shows a schematic partition diagram of the liquid crystal display of FIG. 2A;

FIG. 3B shows a schematic diagram of a frame period during which the liquid crystal display in FIG. 3A displays a frame;

FIG. 4A shows a schematic timing diagram of the frame period in FIG. 3B;

FIG. 4B shows another timing diagram of the frame period of the liquid crystal display in FIG. 3A;

Fig. 5 shows a flowchart of a driving method according to an embodiment of the present invention.

Detailed ways

The liquid crystal display of the present invention inserts a black frame within the frame time of the display frame, which can effectively solve the problem of residual image caused by fast dynamic frame changes. The display area of the liquid crystal display of the present invention is divided into a plurality of scanning areas, the blank period is allocated to each scanning area, and all pixels in one scanning area are turned into a dark state at a time, so as to achieve the purpose of inserting black frames. The liquid crystal display proposed by the present invention can insert black frames within one frame time without increasing the frame update rate.

FIG. 2A shows a structure diagram of a liquid crystal display according to an embodiment of the present invention. Each pixel of the display panel 203 is controlled by the scan driver 202 via a scan line, and receives data transmitted by the data driver 201 via a data line. For example, the pixels 204 of the display panel 203 are controlled by the scan driver 202 through the first scan line S1, and respectively receive data transmitted by the data driver through the data line D1. The rest of the pixels of the display panel 203 can be deduced by analogy. Wherein, the embodiment of the present invention takes 1280×1024 resolution as an example, and in practical application, the liquid crystal display of the present invention is not limited to this resolution.

FIG. 2B shows a block diagram of the pixel 204 of FIG. 2A. Wherein, the pixel 204 includes a transistor 205 , a liquid crystal capacitor C _LC , and a storage capacitor C _ST . The gate of the transistor 205 is coupled to the first scan line S1, the drain of the transistor 205 is coupled to the data line D1, and the liquid crystal capacitor C _LC and the storage capacitor C _ST are connected between the source of the transistor 205 and the common electrode V _com .

Please refer to FIG. 3A , which shows a schematic partition diagram of the liquid crystal display in FIG. 2A . The 1024 scanning lines of the liquid crystal display of Fig. 2A are evenly distributed to 42 scanning areas, so that the first scanning area B1 to the 41st scanning area B41 all have 24 (rounding up to 1024/42) scanning lines, and the 42nd scanning area B42 has 40 (1024-24×41=40) scanning lines. For example, the first scan area B1 includes the first scan line S1 to the twenty-fourth scan line S24 . The 42nd scan area B42 includes the 985th scan line S985 to the 1024th scan line S1024 .

Please refer to FIG. 3B , which shows a schematic diagram of a frame period during which the liquid crystal display in FIG. 3A displays a frame. The liquid crystal display displays a frame in a frame period T _D , and the frame period T _D includes 1024 scanning line periods TS1 ~ TS1024, and blanking time (blanking time), each scanning line of the display is in one of the scanning line periods Enabled internally, the blank period is divided into 42 black line insertion periods. As shown in FIG. 3B , the frame period T _D is divided into 42 scanning area periods TB1 - TB42 , which respectively correspond to the 42 scanning areas B1 - B42 of the display area of the display. The 1024 scanning line periods and 42 black line inserting periods are evenly distributed to these 42 scanning area periods, so that the first scanning area period TB1 to the 41st scanning area period TB41 all include a black line inserting period and 24 (for 1024/ 42 is an integer) scan line periods, and the 42nd scan area period TB42 includes a black line insertion period and 40 (1024−24×41=40) scan line periods. Wherein, the time length of each scanning line period is equal to that of each black line inserting period. The 24 scan lines from the first scan area B1 to the 41st scan area B41 are respectively enabled in the 24 scan line periods from the first scan area period TB1 to the 41st scan area period TB41 . The 40 scan lines included in the 42nd scan area B42 are respectively enabled in the 40 scan line periods of the 42nd scan area period TB42. Please note that the first line period of each scanning area period in this embodiment is the black line insertion period. In practical applications, for each scanning area period, the black line insertion period can be located at the any position.

In this embodiment, the black frame insertion method of the liquid crystal display in this embodiment is described by taking all the pixels in the 21st scanning area as an example to turn to the dark state first. FIG. 4A shows a schematic timing diagram of the frame period in FIG. 3B. When the liquid crystal display scans a frame, firstly, when the black line insertion period TI1 is located in the first scanning period TB1 , the pixels corresponding to all the scanning lines in the 21st scanning zone B21 are turned into a dark state. Next, when the first scan line period TS1 is located in the first scan area period TB1, the first scan line S1 is enabled. The second scan line S2 is enabled when it is located in the next scan line period TS2 of the first scan period TB1. Afterwards, all actions in the first scanning period TB1 can be deduced by analogy. Next, when the black line insertion period TI2 is located in the second scanning period TB2, the pixels corresponding to all the scanning lines in the 22nd scanning zone B22 are turned into a dark state. Afterwards, all actions in the second scanning period TB2 are the same as those in the first scanning period TB1 , and will not be repeated here.

When the black line insertion period TI22 is located in the 22nd scanning period TB22 , all pixels corresponding to the scanning lines of the 42nd scanning zone B42 are turned into a dark state. Next, when the black line insertion period TI23 is located in the 23rd scanning period TB23 , all the pixels corresponding to the scanning lines in the first scanning zone B1 are turned into a dark state. When the black line insertion period TI24 is located in the 24th scanning period TB24, all the pixels corresponding to the scanning lines of the second scanning zone B2 are turned into a dark state. After that, all the actions of inserting black frames can be deduced by analogy.

In another embodiment, each of the 1st to 26th scanning areas has 24 scanning lines, and each of the 27th to 42nd scanning areas has 25 scanning lines. Each of the 1st to 26th scanning area periods includes 24 scanning line periods, and each of the 27th to 42nd scanning area periods includes 25 scanning line periods.

The liquid crystal display of the present invention evenly distributes the scanning line period to each scanning area period, so that the sum of the enabling time of the scanning line in the first scanning area B1 and the enabling time of the scanning line in the 41st scanning area B41 are all equal, which can be effectively Solve the problem that in traditional liquid crystal displays, the enabling time of each scanning line is not equal, resulting in the problem that the lower half of the frame is darker than the upper half.

In this embodiment, the pixels corresponding to all the scanning lines in the 21st scanning area B21 are first turned to the dark state as an example. state. For example, in another embodiment, the pixels corresponding to all the scanning lines in the 11th scanning area B11 first turn to the dark state, that is, when the black line insertion period TI1 in the 1st scanning area period, the pixels in the 11th scanning area B11 All the pixels corresponding to the scan line are turned into a dark state, and the rest of the operations of inserting black frames are the same as above. And in the timing diagram of the frame period shown in FIG. 4A , the black line insertion period of each scanning area period is the first line period of each scanning area period. In practical application, the black line inserting period of each scanning area period can be at any position of each scanning area period.

FIG. 4B shows another timing diagram of the frame period of the liquid crystal display in FIG. 3A . The liquid crystal display displays a frame in a frame period _TD , and the frame period _TD includes 1024 scan line periods TS1˜TS1024 and a blank period. The 1024 scan line periods TS1 - TS1024 are divided into 42 scan zone periods, respectively corresponding to the 42 scan zones B1 - B42 of the display area of the display. Before each scanning period, there is a black line period. So that the first scanning period TB1' to the 41st scanning period TB41' all include 24 (round up 1024/42) scanning line periods, and the 42nd scanning period TB42' includes 40 (1024-24×41=40) scan line period. Before the first scanning period TB1' is the first black line insertion period TI1', before the second scanning period TB2' is the second black line insertion period TI2', and the relationship between the rest of the scanning period and the black line period is analogous .

In FIG. 4B , when the liquid crystal display scans a frame, first, when it is in the first black line insertion period TI1', the pixels corresponding to all the scanning lines in the 21st scanning area B21 are turned into a dark state. Next, when it is in the first scan line period TS1 of the first scan area period TB1', the first scan line S1 of the liquid crystal display is enabled. When the next scan line period TS2 of the first scan area period TB1' is located, the second scan line S2 is enabled. Afterwards, all actions in the first scanning period TB1' can be deduced by analogy. Next, when it is in the second black line insertion period TI2', the pixels corresponding to all the scanning lines in the 22nd scanning area B22 are turned into a dark state. Afterwards, all actions of the second scanning period TB2' are the same as those of the first scanning period TB1, and will not be repeated here.

When it is in the 22nd black line insertion period TI22', all the pixels corresponding to the scan lines in the 42nd scan area B42 are turned into a dark state. Next, when it is in the 23rd black line insertion period TI23', all the pixels corresponding to the scanning lines in the first scanning area B1 are turned into a dark state. When it is in the 24th black line insertion period TI24', all the pixels corresponding to the scanning lines in the second scanning area B2 are turned into a dark state. After that, all the actions of inserting black frames can be deduced by analogy.

In FIG. 4B , it is taken as an example that each black line inserting period is arranged before each scanning area period. In practical application, each black line inserting period may also be arranged after each scanning area period. In addition, in this embodiment, the pixels corresponding to all scanning lines in the 21st scanning area B21 are first turned into a dark state as an example. In practical applications, the pixels corresponding to any scanning area in the 42 scanning areas can be first turned into dark state. For example, in another embodiment, the pixels corresponding to all the scanning lines in the eleventh scanning area B11 are first turned into a dark state, that is, when the first black line insertion period TI1' is located, the scanning lines in the eleventh scanning area B11 All the corresponding pixels are turned into a dark state, and other operations of inserting a black frame are the same as above.

The liquid crystal display of the present invention can be a normally white (normally white) or normal black (normally black) display. The liquid crystal display includes a scan driver for driving the scan lines in the scan areas, the scan driver includes a first shift register and a second shift register, the first shift register is used to control the black line insertion period, the second shift register The bit register is used to control the scan line period. The number of scanning lines contained in each scanning area of the liquid crystal display is not necessarily equal.

Fig. 5 shows a flowchart of a driving method in one frame according to an embodiment of the present invention. The driving method of the present invention is used in a liquid crystal display, and the display area of the liquid crystal display has M scanning areas, and each scanning area includes several scanning lines. The period in which a frame is displayed in the display area is a frame period, and the frame period is divided into a plurality of scanning area periods, respectively corresponding to each scanning area, and each scanning area period includes a black line insertion period and a plurality of scanning line periods. Firstly, in step 400, when the black insertion period of the S-th scanning area located in the M scanning areas, it is judged whether (S+N) is greater than M, and N is a positive integer between 1 and M. If no, the method proceeds to step 410; if yes, the method proceeds to step 440. In step 410, the pixels corresponding to all the scan lines in the (S+N)th scan area are turned into a dark state. In step 440, all the pixels in the (S+N-M)th scanning area of the M scanning areas are turned into a dark state. Next, in step 420, when the scanning line period of the S-th scanning area is located, the scanning lines of the S-th scanning area are enabled sequentially. In step 430, it is determined whether all the pixels in the scanning area have switched to the dark state. If yes, it means that a black frame has been inserted in one frame period, and the method ends; In step 450, S is incremented by 1, that is, the above-mentioned steps of the method are repeated in the next scanning area period until all pixels in the scanning area have switched to the dark state.

For example, M in the above-mentioned method flow chart is 42, and N is 20. When it is located in the first scanning area period (that is, S is 1), step 400 is no, so when it is located in the black line insertion period of the first scanning area period, the The pixels corresponding to all the scan lines in the 21st scan area are turned into a dark state. When it is in the scanning line period of the first scanning area, the scanning lines of the first scanning area are enabled. When it is in the 23rd scanning area period, step 400 is yes, indicating that the last 22 scanning areas of the 42 scanning areas have been converted to the dark state, and the first 20 scanning areas must be converted to the dark state. Therefore, when the black line is inserted in the 23rd scanning area, the pixels corresponding to all the scanning lines in the 1st scanning area are turned into a dark state.

The black line insertion period of each scanning area period in the above embodiment is the first line period of each scanning area period. In practical application, the black line inserting period of each scanning area period can be at any position of each scanning area period.

The liquid crystal display of the present invention utilizes the blank time in the frame time of displaying a frame to insert a black frame, divides the display area of the liquid crystal display into multiple scanning areas, and distributes the blank time equally to each scanning area. By turning the pixels in one scanning area into a dark state at a time, the effect of inserting a black frame is realized without increasing the frame update rate, and it can solve the problem that the lower half of the frame of a traditional liquid crystal display is darker than the upper half.

In summary, although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. A liquid crystal display, used to display one frame in one frame period, comprising: M scanning areas, each of which includes a plurality of scanning lines, each of which corresponds to a column of pixels, and M is a positive integer; Wherein, the frame period includes M scanning area periods, respectively corresponding to the scanning areas, and the scanning area period of each scanning area includes a plurality of line periods, and the line periods include a black line insertion period and a plurality of Scanning line period; when the black line insertion period is located in the S scan zone period in the scan zone periods, the pixels corresponding to the scan lines in the (S+N) scan zone of the scan zones Turning into a dark state, when these scan lines are located in the S scan area period, the scan lines in the S scan area are enabled; S is a positive integer less than or equal to M, and N is less than or equal to A positive integer equal to M. 2. The liquid crystal display as claimed in claim 1, wherein when (S+N) is greater than M, when the black line insertion period is located in the Sth scanning area, the said (S+N-M) scanning area The pixel corresponding to the scan line turns to dark state. 3. The liquid crystal display as claimed in claim 1, wherein the f-th line period among the line periods is the black line insertion period, and f is a positive integer. 4. The liquid crystal display as claimed in claim 1, wherein the time lengths of the line periods of the scanning zone periods of each of the scanning zones are equal. 5. The liquid crystal display as claimed in claim 1, wherein each black line insertion period is a part of a blanking time. 6. The liquid crystal display as claimed in claim 1, wherein the number of the scanning lines included in each of the scanning areas is equal. 7. The liquid crystal display as claimed in claim 1, wherein the numbers of the scanning lines contained in each of the scanning areas are not equal. 8. The liquid crystal display as claimed in claim 1, wherein the liquid crystal display comprises a scan driver for driving the scan lines of the scan areas, the scan driver comprising: The first shift register is used to control the black line insertion periods; and The second shift register is used to control the scan line periods. 9. A driving method for driving a display, the display has a display area, the display area is divided into M scanning areas, each of the scanning areas includes a plurality of scanning lines, and the display area displays a period of one frame as a frame Period, the frame period is divided into M scanning area periods, respectively corresponding to these scanning areas, each of the scanning area periods includes a plurality of line periods, and these line periods include a black line insertion period and a plurality of scan lines time period, the method includes: During the black line insertion period of the Sth scanning area period of the scanning areas, the pixels corresponding to the scanning lines of the (S+N)th scanning area of the scanning areas are turned into a dark state; and Enabling the scan lines of the S scan area during the scan line periods of the S scan area; Wherein, M is a positive integer, S is a positive integer less than or equal to M, and N is a positive integer less than or equal to M. 10. A driving method for driving a display with frame data, the display comprising a first scanning area and a second scanning area, the driving method comprising: driving the second scanning area to a dark state during the first black line insertion period; During the period of the first scanning area, driving the first scanning area with the first part of the frame data; driving the first scanning area to a dark state during the second black line insertion period; and During the period of the second scanning area, the second scanning area is driven by the second part of the frame data.

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