JP3131821B2 - Matrix type display panel drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix type display panel driving device used mainly for a matrix type display panel such as a liquid crystal panel.

[0002]

2. Description of the Related Art A conventional matrix type display panel driving apparatus will be described below with reference to the drawings. FIG. 3 is a block diagram showing a schematic configuration of a conventional matrix type display panel driving device and a liquid crystal panel driven by the driving device.
In the figure, reference numeral 30 denotes a matrix type display panel driving device, 31 denotes a shift register for serially transmitting a sampling start signal for capturing a video signal, and 32 denotes a shift register.
31 is a sampling signal input terminal for inputting a sampling signal, 33 is a shift clock input terminal of the shift register 31, 34 is a video signal input terminal, and 35 is a video signal input terminal 34
A sample-and-hold circuit group that samples the video signal input from the multiplexing circuit based on the sampling signal of the shift register 31 and then holds the sampled signal. , 37 are output control signal input terminals of the buffer circuit group 36, 38 is a liquid crystal panel driven by the matrix type display panel driving device 30, a broken line frame 39 is a display area of the liquid crystal panel 38, and 3A is a place other than the display area 39. 3B is the rescue line 3
A broken data line connected to A, 3C is a normal data line that is not broken, 3D is a driving device for line-sequential scanning of the liquid crystal panel 38, 3D is a scanning electrode for line-sequential scanning of the liquid crystal panel 38. Reference numeral 3F denotes a scanning signal generator for driving the scanning electrode 3E.

FIG. 4 is a timing chart of signals passing through various parts inside the matrix type display panel driving device 30 shown in FIG. 3, where 40 in FIG. 4A is a horizontal synchronizing signal, and 41 in FIG. 42, a sampling start signal 42 of the sample-hold circuit group 35, an output control signal 43 of the buffer circuit group 36, and a normal data line 3C 44 of FIG. Drive voltage waveform, 45 is a broken data line 3B
Is a drive voltage waveform when the rescue process is performed, and shows a voltage waveform changed by the influence of the capacitance component and the resistance component of the rescue line 3A.

[0004] The operation of the conventional liquid crystal matrix type display panel driving device configured as described above will be described. The matrix type display panel driving device 30 drives the liquid crystal panel 38 as follows. First, a sampling start signal 42 input from the sampling signal input terminal 32 is used as a start pulse, and each output pulse of the shift register whose clock is the shift clock input from the shift clock input terminal 33 is input from the video signal input terminal 34. The display period of the video signal 41
35, the output control signal 43 is set high during the blanking period of the horizontal synchronization signal 40 of the video signal 41, and the buffer circuit group is set.
The driving voltage 44 is output from the 36 to the liquid crystal panel 38. In the matrix type display panel driving device 30 having only one system of the sample and hold circuit group 35, when the output control signal 43 is low, the output of the buffer circuit group 36 becomes high impedance, and in the meantime, it is charged when the output control signal 43 is high. The liquid crystal panel 38 is driven by the applied voltage.

Next, in the manufacturing process of the liquid crystal panel 38, for example,
In the case where the source wiring 3B is disconnected from the source wiring in the display area 39 due to the entry of foreign matter or the like, a portion (the scanning electrode 3E or the like on the lower side in FIG. 3) linked to the wiring ahead of the disconnected part is detected. Control becomes impossible, and a linear display error occurs. As means generally used to rescue the disconnected data line 3B, the data line 3B disconnected by the rescue line 3A provided in a place other than the display area 39 of the liquid crystal panel is connected to the matrix type display panel driving device. It is connected to 30 buffer circuits 36 so that the drive voltage 44 can be applied to reduce the display abnormalities and increase the yield.

[0006]

However, in the above-described configuration, since the wiring longer than usual is driven by using the rescue line, the capacitance component and the resistance component are increased as compared with the unbroken data line. As a result, the output waveform is distorted like the drive voltage waveform 45 shown in FIG. 4E, and as a result, there is a problem that a luminance difference occurs between the rescued data line and the normal data line.

The present invention solves such a conventional problem. By independently providing a second buffer circuit group having improved driving capability, the influence of the capacitance component and the resistance component of the rescue wiring can be improved. It is an object of the present invention to provide a matrix-type display panel driving device which prevents the occurrence of a luminance difference due to the above.

[0008]

According to the present invention, there is provided a matrix type display panel in which data lines and scanning lines are arranged in a matrix and having display pixels at intersections thereof, and a video signal for driving the matrix type display panel. A first sample and hold circuit group, a first buffer circuit group connected to each stage output of the first sample and hold circuit group, and an input terminal independent of the first sample and hold circuit group A second sample-and-hold circuit group having a sampling control terminal, and a second buffer connected to an output of the second sample-and-hold circuit group and having a higher driving ability than the first buffer circuit group A rescue line connected to an output of the second buffer circuit; Applying the output of Ffa circuit to an input terminal of said second sample and hold circuits, in which so as to drive the rescue line by the being cooperative to the second buffer circuit.

According to the present invention, it is hard to be affected by the capacitance component and the resistance component of the rescue wiring, and the occurrence of a luminance difference can be prevented.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a matrix type display panel driving device and a liquid crystal panel driven by the same according to an embodiment of the present invention. In the figure, 1 is a matrix type display panel driving device of the present invention, 2 is a shift register for serially transmitting a sampling signal for taking in a video signal, 3 is a sampling signal input terminal for inputting a sampling start signal to the shift register 2, and 4 is A shift clock input terminal 5 of the shift register 2, a video signal input terminal 5, a video signal input from the video signal input terminal 5, a first sample and hold that samples the video signal based on the sampling signal of the shift register 2, and then holds the sampled video signal A first buffer circuit group 7 for transmitting a video signal captured by the first sample and hold circuit group 6 to a liquid crystal panel described later; an output control signal input terminal of the first buffer circuit group 7; 9 is a second sample and hold circuit independent of the first sample and hold circuit group 6 , 10 second sample-and-hold circuit group 9 high first driving capability than the buffer circuit group 7 leading to the second buffer circuit group, the sampling signal input terminal of the second sample-and-hold circuit group 9 11, 12
Converts the video signal from the first buffer circuit group 7 into the second sample and hold circuit group 9 during rescue processing.
Is a liquid crystal panel driven by the matrix-type display panel driving device 1;
Is a display area of the liquid crystal panel 13, and 15A and 15B are display areas.
A rescue line arranged at a position other than 14; 16 is a disconnected data line connected to the rescue lines 15A and 15B; 17 is a normal data line which is not disconnected; and 18 is a line for scanning the liquid crystal panel 13 line by line. A driving device 19 is a scanning electrode for line-sequentially scanning the liquid crystal panel 13, and a scanning signal generator 20 drives the scanning electrode 19.

FIG. 2 is a timing chart of signals passing through various parts of the matrix type display panel driving device 1 shown in FIG. 1. In FIG. 2A, reference numeral 21 denotes a horizontal synchronizing signal, and FIG. The signal 23 in FIG. 3C is a sampling signal of the first sample and hold circuit group 6, the reference numeral 24 in FIG. 4D is the output control signal of the first buffer circuit group 7, and the reference numeral 25 in FIG. The sampling number of the second sample-hold circuit group 9 and 26 in FIG.

Next, the operation of the liquid crystal matrix type display panel driving apparatus of the present invention configured as described above will be described. The normal operation is the same as that of the conventional device. First, a shift register using the sampling signal 23 input from the sampling signal input terminal 3 as a start pulse and the shift clock input from the shift clock input terminal 4 as a clock is used. The display period of the video signal 22 input from the video signal input terminal 5 by each output pulse is taken into the first sample and hold circuit group 6, and the output control signal 24 is output during the blanking period of the horizontal synchronizing signal 21 of the video signal 22. To a high level to output a drive voltage waveform 26 from the first buffer circuit group 7 to the liquid crystal panel 13. Here, when a disconnection occurs in the data line 16, the data line 16 is connected to the output terminal of the second buffer circuit group 10 having increased driving capability through a long rescue line 15B arranged on the liquid crystal panel 13. At the same time, the output of the first buffer circuit group 7 for driving the disconnected data line 16 is output to the liquid crystal panel 13.
The short rescue line 15A is applied to the input terminal of the second sample and hold circuit group 9 via the short rescue line 15A.

The second sample and hold circuit group 9 samples the drive voltage of the first buffer circuit group 7 while the sampling signal 25 input from the sampling signal input terminal 11 is high, and increases the drive capability. Through the second buffer circuit group 10 and the rescue line 15B, the side of the disconnected data line 16 that is not connected to the driving device is driven. Since the second buffer circuit group 10 has a sufficiently high driving capability, it can sufficiently charge the long rescue line 15B. Therefore, as shown in the driving voltage waveform 26 of FIG. Can be made the same as the drive voltage waveform of the data line 17 without disconnection.

According to the present embodiment, a buffer circuit having an increased driving capability is arranged in front of the rescue line, thereby driving the rescue line. The voltage level does not change, and the occurrence of a situation where the rescued data line has a different luminance than the other data lines is prevented.

In this embodiment, a matrix type display panel using liquid crystal has been described as an example.
Of course, the present invention can be applied to other matrix type display panel display devices.

[0016]

As described above, during the rescue processing, the rescue line is driven by the buffer circuit having a higher driving capability, independent of the circuit of the video input signal forming the image. The driving voltage can be continuously output without making the output of the buffer circuit high impedance even during signal input. For this reason, it is possible to prevent a waveform from being changed or a voltage level from being changed due to a capacitance component or a resistance of the rescue line, so that the rescued data line has a different luminance than other data lines. This has the advantageous effect of eliminating points.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a matrix type display panel driving device of the present invention.

FIG. 2 is a timing chart of signals in an embodiment of a matrix type display panel driving device of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of an example of a conventional matrix type display panel driving device.

FIG. 4 is a timing chart of signals in a conventional matrix display panel driving device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Matrix type display panel drive device, 2 ... Shift register, 3 ... Sampling signal input terminal, 4 ... Shift clock input terminal, 5 ... Video signal input terminal, 6 ...
A first sample-hold circuit group, 7: a first buffer circuit group, 8: an output control signal input terminal, 9: a second sample-hold circuit group, 10: a second buffer circuit group,
11… Sampling signal input terminal, 12… Input terminal,
13: LCD panel, 14: Display area, 15A, 15B: Rescue line, 16: Disconnected data line, 17:
Normal data line, 18 ... Drive device, 19 ... Scan electrode, 20 ... Scan signal generator.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G09G 3/36 G02F 1/133 G09G 3/20

Claims (1)

(57) [Claims] 1. A matrix display panel having data lines and scanning lines arranged in a matrix and having display pixels at intersections thereof, and a first sample hold for converting a video signal into a driving voltage for the matrix display panel. A circuit group, a first buffer circuit group connected to each stage output of the first sample and hold circuit group, and an input terminal independent of the first sample and hold circuit group. A second sample and hold circuit group, a second buffer circuit group connected to an output of the second sample and hold circuit group, and having a higher driving capability than the first buffer circuit group; A rescue line connected to an output of the buffer circuit, wherein during a rescue process of the data line, the output of the first buffer A matrix type display panel driving device, wherein the rescue line is driven by the second buffer circuit associated with the input terminal of a sample-hold circuit group.