JPS63218927A - Picture display device - Google Patents

Abstract

PURPOSE:To amplify the circuit of the titled device, and to realize its high integration by using a decoder for a horizontal/vertical scanning circuit of a liquid crystal display device. CONSTITUTION:On a glass substrate 1 by quartz, a picture element 2 is arrayed in a matrix shape, and a vertical/horizontal scanning circuit is constituted of decoders 4, 7 instead of a conventional vertical/horizontal scanning circuit by a D-flip-flop. In such a way, the total number of transistors for constituting the scanning circuit is decreased. Also, the decoders 4, 7 are merely NOR circuit fundamentally, therefore, even if a timing of a pulse is not adjusted completely, it does not occur that the decoders do not operate.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an image display device.

BACKGROUND OF THE INVENTION Liquid crystal display devices, which are a type of conventional image display device, are used in many fields due to their low power consumption and thinness. In particular, active matrix type liquid crystal display devices have come to be used in pocket televisions.

Recently, active matrix type liquid crystal display devices incorporating a shift register, in which the shift register is simultaneously formed on a glass substrate, have been actively researched for further miniaturization.

Hereinafter, an active matrix type liquid crystal display device having a built-in shift register as described above will be described with reference to the drawings.

FIG. 4 shows a configuration diagram of a conventional active matrix (IJ) wax type liquid crystal display device incorporating a built-in shift register.

In FIG. 4, pixels 2 are arranged in a matrix on a glass substrate 1, and each pixel 2 is a thin film transistor (TPT).
) is equipped with switch 3. Furthermore, TPT switch 3
a vertical scanning circuit 14 for driving the readout gate of the
Further, a horizontal scanning circuit 17 for sequentially transferring video signals inputted from the input signal terminal 6 to each signal line 6, and the like are formed on the same glass substrate 1.

The shift registers of the vertical scanning circuit 14 and the horizontal scanning circuit 17 are constituted by static shift registers such as D flip-flops.

Problems to be Solved by the Invention However, when shift registers in vertical scanning circuits and horizontal scanning circuits are constructed using D flip-flops as described above, the circuit becomes complicated and it is difficult to increase the degree of integration. . Furthermore, there is also the problem that the production yield of liquid crystal display devices becomes poor. In addition, there was a problem that the device would not work if the timing of the pulses was incorrectly adjusted.

In view of the above drawbacks, the present invention provides an image display device in which a vertical scanning circuit and a horizontal scanning circuit are configured with simple circuits.

Means for Solving the Problems In order to solve the above problems, in the image display device of the present invention, the vertical scanning circuit and the horizontal scanning circuit are constructed of decoders.

Effect: This configuration reduces the total number of transistors for configuring the scanning circuit. Furthermore, since the decoder is basically a simple N,OR circuit, it will not stop operating even if the timing of the pulses is incorrectly adjusted.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a circuit diagram of an active matrix type liquid crystal display device according to an embodiment of the present invention.

Pixels 2 are arranged in a matrix on a glass substrate 1 made of quartz.
are arranged. The pixel 2 is constructed by inserting liquid crystal between two transparent electrode plates. The pixel 2 includes a thin film transistor (TPT) switch 3 made of polysilicon or amorphous silicon. Furthermore, T.P.
A decoder (vertical direction) 4 for driving the readout gate of the T switch 3, a sample hold circuit 8 for sequentially transferring the video signal input from the input signal terminal 5 to each signal line 6, and a decoder (horizontal direction) direction) 7 is formed on the glass substrate 1.

In particular, in place of the conventional vertical/horizontal scanning circuits 4, 7 using flip-flops, in the present invention, the vertical/horizontal scanning circuits 4, 7 are constructed using decoders.

A circuit diagram of the decoder is shown in FIG. In the embodiment of the present invention, a case will be described in which the number of output signal lines 22 is 256. In this case, if the number of address signal lines 21 is 16, it is possible to sequentially drive 266 output signal lines 22.

By applying appropriate pulses to the address signal line 21, the output signal lines 22 can be sequentially driven. By using this recorder in a vertical scanning circuit and a horizontal scanning circuit, pixels arranged in a matrix can be driven. 2, video signals can be transferred in sequence.

Further, as an embodiment of the present invention, a circuit diagram of a unit of a decoder is shown in FIG. Basically, it is composed of 8 CMOS input NOR circuits.

In particular, since the horizontal scanning decoder 7 requires high-speed operation on the order of I MHz, it is advantageous to configure the NOR circuit with a CMOS circuit. Furthermore, although the electrical characteristics of the thin film transistor 3 are generally unstable, stable operation is possible if the decoder is configured with 4CMO8 circuits.

Further, the n-channel TFT 31 and the p-channel TFT 32 of the 0M08 circuit are formed of a thin film semiconductor such as polysilicon, amorphous silicon, recrystallized silicon, etc. formed on the glass substrate 1.

Furthermore, if the output current or output voltage from the decoder is insufficient, a buffer amplifier 33 may be added. In this embodiment, both the vertical scanning circuit and the horizontal scanning circuit are configured with decoders, but the effect can be obtained even if only one of the scanning circuits is configured with a decoder.

Effects of the Invention As described above, by using a decoder in the horizontal and vertical scanning circuits of a liquid crystal display device, the circuit is simpler than the conventional D flip-flop, and higher integration is possible.
Furthermore, manufacturing yield is also increased.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a decoder according to an embodiment of the present invention, and FIG. 3 is a unit unit of a decoder according to an embodiment of the present invention. FIG. 4 is a circuit diagram of a conventional liquid crystal display device. 1...Glass substrate, 2...Pixel, 3...
...TFT switch, 4...Decoder (vertical scanning circuit), 5...Input signal terminal, 6...
... Signal line, 7 ... Decoder (horizontal scanning circuit), 8 ... Length pull-hold circuit, 21 ...
...address signal line, 22...output signal line,
23... Decoder unit, 31...
. . . n-channel TFT, 32 . . . p-channel TFT, 33 . . . buffer amplifier. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--Crow's description 4 anti-2--one side system 3--TFT screen (indentation) key-decoder (all 1 j ghost ship 5-m-manpower gate) vendor?---Punfu 21-1-Address 21-1-A 22-11 output

Claims (1)

[Claims] An image display device characterized in that pixels are arranged in a matrix on an insulating substrate, and at least one of a vertical scanning circuit and a horizontal scanning circuit that scans the pixels is constituted by a decoder.