JP3200536B2 - Liquid crystal display device and liquid crystal driving IC - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having pixels arranged in a matrix and a liquid crystal driving IC.

[0002]

2. Description of the Related Art FIG. 7 shows an element surface of a conventional liquid crystal driving IC.
Is a power and ground terminal required for driving the liquid crystal driving IC, 33 is an input terminal group for inputting a signal of image information data, and 34 is an output terminal group for a signal supplied to a source line of the liquid crystal panel. .

A method for connecting the output terminal group 34 of the chip 31 of the liquid crystal driving IC to a liquid crystal display device is as follows.
T connected to the glass substrate of the liquid crystal panel through the film
AB (Tape Automated Bondin)
g) A mounting method, a COG (Chip On Glass) mounting method of directly mounting a chip on a glass substrate, or the like is generally realized.

On the other hand, image information data is input to an input terminal group 33. In the case of a digital liquid crystal driving IC, a plurality of bit data is input to express a gray scale, and in the case of a color liquid crystal display device, three times as much as three times to express red, green and blue. Bit data is required. In general, when an 8-bit / color configuration, which is generally required to express a natural image without difficulty, is used, a total of 24 data bits are required, and at least 24 bus lines are required. Becomes

[0005]

In recent years, liquid crystal displays for personal computers have tended to increase the number of input data bits in order to express an image close to a natural image. However, as the number of input terminals increases, the pitch between input terminals decreases, and connection to the terminals becomes more difficult.

[0006] Further, as the shift to higher resolution capable of displaying a large amount of information progresses, the frequency of an input signal tends to increase more and more. In both cases of an increase in the number of data bits and an increase in the data frequency, peripheral circuits of the liquid crystal display device become complicated, and unnecessary radiation further increases.
An object of the present invention is to provide a liquid crystal display device and a liquid crystal driving IC that can reduce unnecessary radiation and reduce the number of data signal input terminals in view of such problems.

[0007]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: an array substrate on which a thin film transistor for forming a pixel is formed; and a multi-bit array disposed around the array substrate.
A connector for supplying a signal of image information data, which is an electric signal of the image signal, and a power supply voltage; and a connector connected to the connector.
Converting the electrical signals of the multi-bit and parallel-serial conversion circuit for parallel-serial conversion, and a printed board mounted with a light emitting element for converting into an optical signal by inputting the output signal into an electrical signal by inputting said optical signal A liquid crystal driving IC having a processing circuit for processing a signal of the light receiving element and outputting an electric signal for driving the array substrate, and having an output terminal connected to the array substrate; With
The liquid crystal driving IC is connected by a TAB or COG method, and the light emitting element is arranged at a position facing an element surface of a chip of the liquid crystal driving IC.

A liquid crystal driving IC according to a second aspect is a multi-bit liquid crystal driving IC.
A connector for supplying a signal and power supply voltage of the image information data which is an electrical signal, before being connected to the connector
Serial and parallel-serial conversion circuit for parallel-serial conversion of the electrical signals of the multi-bit, implement a light emitting element for converting into an optical signal by inputting the output signal, and the periphery of the array substrate provided with the thin film transistor forming a pixel A liquid crystal driving IC disposed opposite to a printed circuit board disposed thereon, a light receiving element for inputting an optical signal of the light emitting element and converting it into an electric signal, and an output terminal connected to the array substrate;
A processing circuit provided on a surface of the same chip as the light receiving element, for processing a signal of the light receiving element and outputting an electric signal for driving the array substrate.

[0009]

According to the liquid crystal display device of the present invention, the multi-bit electrical signal is converted from parallel to serial by the parallel / serial conversion circuit, and the output signal is converted into an optical signal by the light emitting element.
Further, the light receiving element of the liquid crystal driving IC converts the signal into an electric signal, processes the electric signal, and outputs an electric signal for driving the array substrate from the output terminal to the array substrate. Therefore, the number of input terminals can be significantly reduced, and unnecessary radiation can be reduced. In addition, since an optical signal input method that does not generate jamming radio waves is used, data with a higher frequency can be input. Also, the data bus wiring required for transmitting a data signal at a high speed by an electric signal can be greatly reduced.

According to the liquid crystal driving IC of the second aspect, since an optical signal is input, an input terminal for electrical connection is not required, connection reliability is improved, and the area of the peripheral circuit portion of the array substrate is reduced. And unnecessary radiation can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory view of a liquid crystal display device in which a liquid crystal driving IC is mounted by TAB, and FIG.
FIG. 3 is an explanatory diagram showing a signal flow of the liquid crystal driving device, and FIG. 4 is an explanatory diagram viewed from the element surface of the liquid crystal driving IC.

A liquid crystal display device (hereinafter, referred to as a TFT liquid crystal panel) has thin film transistors (hereinafter, referred to as TFTs) forming pixels arranged in a matrix, and a liquid crystal driving IC of a liquid crystal driving device is provided in the liquid crystal display device.
Is TAB-mounted. 1 and 2, 11
Is an array substrate having TFTs formed on a glass substrate, 12 is a color filter substrate, 13 is a tape carrier for leading out a wiring group of the array substrate 11, 14 is a liquid crystal driving IC mounted on the tape carrier 13, 15 Denotes a printed circuit board on which a liquid crystal driving device such as a liquid crystal driving IC 14 is mounted. Reference numeral 16 denotes a connector for supplying a signal of image information data and a power supply voltage on the printed circuit board 15, and reference numeral 17 denotes a light emitting element such as a light emitting diode for converting an electric signal into an optical signal.

A signal such as image information data supplied to the connector 16 is transmitted to a parallel / serial conversion circuit 4 on a printed circuit board 15.
3 ( FIG. 4 ), and is supplied to the light emitting element 17 (FIG. 2) below the liquid crystal driving IC 14. At that time, a parallel-serial conversion circuit 43 on the printed circuit board 15, by an electrical signal path is Rushiriaru converted multi-bit (parallel to serial conversion), which simplifies the subsequent circuitry reduces the number of data signals.

In FIG. 3 showing the liquid crystal driving IC 14,
31 is a silicon chip having a processing circuit for processing an input signal and outputting an electric signal for driving a TFT liquid crystal panel, 32 is a power supply and ground terminal necessary for driving a liquid crystal driving IC, 34 Is an output terminal connected to the TFT liquid crystal panel, and 35 is a light receiving element which is an input terminal for converting an optical signal that turns on and off at a high speed into an electric signal.

In FIG. 4, a signal of image information data input to the connector 16 is transmitted via a data bus 41 to
Are supplied to the parallel-serial conversion circuitry 43, the parallel series variable <br/> circuit 43 is provided for each liquid crystal driving IC 14, the signal of the image information data to serial conversion, thereby the number of data lines Can be reduced. In this example,
The 24-bit bus line is set to 3 bits. Parallel direct
The output signal of the column conversion circuit 43 is input to the light emitting elements 17, which are connected to one liquid crystal driving IC 1.
Four are provided for four. The converted optical signal is transmitted to the light receiving element 35 of the liquid crystal driving IC 14 and is converted into an electric signal, and is converted into data necessary for the display operation of the TFT liquid crystal panel. For example, digital-analog conversion, data inversion, sample / Hold and the like, and the array substrate 1
1 is supplied to the upper matrix wiring.

The signal input to the printed circuit board 15 is 8
In the case of 24 bits of bits × 3 (red, green, blue), by mounting three light emitting elements 17 per one liquid crystal driving IC, the signal may be supplied by increasing the frequency by eight times by parallel-serial conversion. Since this high-frequency portion is converted into an optical signal immediately after the parallel-serial conversion, there is almost no need to consider interference such as unnecessary radiation. In the conventional case, the liquid crystal driving IC 14 is
In order to supply a signal to the chip 31 of this example, it was necessary to provide the total number of data bits, that is, 24 input terminals in this embodiment. Since there is no electrical connection of data signals between the chip 31 of the IC for use 14 and the tape carrier and between the tape carrier 13 and the printed circuit board 15, connection reliability is improved and the tape carrier 13 can be made slimmer.

Further, according to the liquid crystal driving IC of this embodiment, since an optical signal is input, an input terminal for electrical connection is not required, connection reliability is improved, and a peripheral circuit portion of a TFT liquid crystal panel is provided. The area can be reduced, and unnecessary radiation can be reduced. FIGS. 5 and 6 show a second embodiment of the present invention. That is, FIG. 5 shows a liquid crystal driving IC,
A TFT liquid crystal panel with TFTs arranged in a matrix
FIG. 6 shows a cross section taken along line CD of FIG. Reference numeral 21 denotes an array substrate having a TFT formed on a glass substrate, reference numeral 22 denotes a color filter substrate, reference numeral 24 denotes a liquid crystal driving IC, and reference numeral 26 denotes a bump for connecting the wiring on the array substrate 21 to the liquid crystal driving IC 24. The bump 26 has a function of electrically connecting the wiring on the array substrate 21 and the IC chip 21. On the other hand, 25 is a printed circuit board, and 27 is a light emitting element for converting an electric signal into an optical signal.

TFT liquid crystal panel and liquid crystal driving IC 2
The electric signal supplied to 4 is supplied to the printed circuit board 25 and transmitted to the light emitting element 27. At this time, the data equivalent to 24 bits is converted into 3-bit data by parallel-serial conversion, further converted into an optical signal, and transmitted to each liquid crystal driving IC 24 by a configuration similar to that of the first embodiment. In this case, since the array substrate 21 is a glass substrate, the optical signal passes without attenuation.

A power supply voltage (not shown) or the like supplied to the liquid crystal driving IC 24 is supplied from a printed circuit board 25 to a power supply line on the array substrate 21 using a flexible substrate or the like. It is transmitted to the driving IC 24.

[0020]

According to the liquid crystal display device of the present invention, the multi-bit electrical signal is converted from parallel to serial by the parallel / serial conversion circuit, and the output signal is converted into an optical signal by the light emitting element. Is converted into an electric signal by the light receiving element and processed, and an electric signal for driving the array substrate is output from the output terminal to the array substrate. Therefore, the number of input terminals can be significantly reduced, and unnecessary radiation can be reduced. In addition, because we adopted an optical signal input method that does not emit jamming,
Higher frequency data can be input.
Further, there is an effect that the data bus wiring required for transmitting a data signal at a high speed by an electric signal can be largely reduced.

According to the liquid crystal driving IC of the second aspect, since an optical signal is input, an input terminal for electrical connection is not required, connection reliability is improved, and the area of the peripheral circuit portion of the array substrate is reduced. And unnecessary radiation can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a liquid crystal display device according to a first embodiment of the present invention in which a liquid crystal driving IC is mounted by TAB.

FIG. 2 is a sectional view taken along line AB.

FIG. 3 is an explanatory diagram of a liquid crystal driving IC viewed from an element surface.

FIG. 4 is an explanatory diagram showing a signal flow of the liquid crystal driving device.

FIG. 5 is an explanatory diagram in which a liquid crystal driving IC according to a second embodiment is mounted by COG.

FIG. 6 is a sectional view taken along line CD.

FIG. 7 is an explanatory view of a conventional liquid crystal driving IC viewed from an element surface.

[Explanation of symbols]

Reference Signs List 11 array substrate 14 liquid crystal driving IC 17 light emitting element 24 liquid crystal driving IC 27 light emitting element 34 output terminal 35 light receiving element 43 parallel serial conversion circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G09G 3/00-3/38 G02F 1/133 505-580 H04B 9/00

Claims (2)

(57) [Claims] An array substrate on which a thin film transistor for forming a pixel is formed, and a multi-bit electric signal disposed around the array substrate.
No. and connector for supplying signals and power supply voltage of the image information data is, the parallel-serial conversion circuit connected to the parallel-serial converting an electric signal of the multi-bit in this connector, the optical signal and input the output signal A printed circuit board mounted with a light emitting element for converting the light into an electric signal; and a light receiving element for inputting the light signal and converting the light signal to an electric signal. The electric signal for driving the array board by processing the signal of the light receiving element And a liquid crystal driving IC having an output terminal connected to the array substrate. The liquid crystal driving IC is connected by TAB or COG method, and the light emitting element is the liquid crystal driving IC. A liquid crystal display device arranged at a position facing an element surface of the chip. 2. A connector for supplying a signal of image information data which is a multi-bit electric signal and a power supply voltage,
And a parallel-serial converter for connecting to serial conversion of the electric signal of the multi-bit in this connector, mounted a light emitting element for converting into an optical signal by inputting the output signal, and forming a thin film transistor forming a pixel A liquid crystal driving IC disposed opposite to a printed circuit board disposed around the array substrate, wherein the light receiving element converts an optical signal of the light emitting element into an electric signal, and is connected to the array substrate. A liquid crystal driving IC comprising: an output terminal; and a processing circuit provided on a surface of the same chip as the light receiving element for processing a signal of the light receiving element and outputting an electric signal for driving the array substrate.