JPS5838768B2 - exiyouhiyoujisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display device, and more particularly to a method of coupling a driving circuit and a display device.

In recent years, liquid crystal display devices have been used in display panels of various measuring instruments, including calculators and watches.

A liquid crystal display device is capable of low-voltage, low-power display, and is particularly advantageous for the above-mentioned small portable devices using battery power.

Since the above-mentioned devices are all portable, they need to be made smaller, so the circuitry (IC or LSI) necessary for the device is
It is desirable to arrange a liquid crystal display (often in the form of

In addition, methods for placing the above-mentioned IC on the electrode board include: (1) placing the packaged IC on the electrode board by soldering, etc., (2) placing the IC in a chip form on the circuit wiring section on the electrode board. Although it is possible to electrically connect the IC chip to the circuit wiring section by wire bonding after placing the IC chip on the electrode substrate, the method of directly face-down bonding the IC chip onto the electrode substrate is most desirable in terms of miniaturization and cost reduction.

An object of the present invention is to improve the face-down method of placing an IC chip onto an electrode substrate constituting a liquid crystal display, thereby further improving cost and workability.

FIG. 1 shows a specific example of the present invention, which shows a cross-sectional structure in which an IC chip is face-down bonded to a liquid crystal display.

1 is the above-mentioned glass substrate, and 2 is the lower glass substrate, which may be made of any material such as soda glass, borosilicate glass, lead glass, etc.

3 and 4 are upper and lower polarizing plates, respectively, 5 is a reflecting plate, 6 is a liquid crystal material, and 7 is a transparent conductive film of Sn02 or In2O3, etc., which is deposited or sprayed on a glass substrate 1,
It is formed in 2.

8 is an IC that includes at least a display driving function, a calculation function, a time measurement function, an A-D conversion function, or various measurement functions, etc.
(or LSI), usually C-M in terms of low power consumption.
There are many O8IC, but other P-MO8IC, ED-MO
It may be shifted to SIC, bipolar IC, etc.

9 is a conductive adhesive that serves to electrically connect and adhesively fix the IC 8 and the transparent conductive film 7, and is printed on the electrode substrate 2, the IC chip 8, or both by a screen printing method, a transfer method, etc. After that, the two are assembled together and adhesively cured.

10 is a mold cap for protecting the IC chip 8 from the outside world and is sealed with an adhesive 11.

Reference numeral 12 denotes a printed circuit board which also serves as a connection to a keyboard, a power source, or an external circuit, and is also electrically connected to and adhesively fixed to the liquid crystal display using a conductive adhesive 13.

In the present invention, as the above-mentioned conductive adhesive, commercially available Fortbond (epoxy type) and the like are photosensitive adhesives that are polymerized and cured by ultraviolet rays or visible rays.

A conductive adhesive is completed by mixing silver powder, nickel powder, carbon powder, copper powder, etc. with this, and then adding a solvent such as butyl carbitol acetate to adjust the viscosity so that it is suitable for screen printing.

The mixing ratio used in the present invention is as follows: Ford bond 21% Silver powder (particle size 2 microns) 62%
Normal butyl carbitol acetate 17% mixture ratio, sheet resistance after stencil screen printing of 325 meshes and curing in sunlight 0.2Ω/5q
uare has been obtained.

Normally, most common conductive adhesives are thermosetting at temperatures of 150°C or higher, but these thermosetting adhesives have a short pot life, so screen printing is possible for a short time, making it difficult for mass production processes. It is not suitable for

(2) If heat curing treatment is performed at 150° C. or higher after liquid crystal injection, the liquid crystal will be extremely deteriorated, bubbles will be generated, and alignment will be disturbed, resulting in fatal defects as a display.

■ If the liquid crystal is injected after bonding the IC with heat curing treatment at 150°C or higher, alignment will be disturbed, and display defects after the liquid crystal injection will immediately cause the integrated IC to be considered defective. Since the parts are disposed of, the number of defective parts due to hold-up increases and costs increase.

There are major drawbacks such as:

In the present invention, as mentioned above, since a photosensitive adhesive is used as a component of the conductive adhesive, its effects include: ■ An infinite pot life can be obtained by screen printing in a dark place, making it suitable for mass production. is easy.

■ Since there is no need for heat treatment during curing, it is possible to completely eliminate deterioration of liquid crystal and liquid crystal alignment.

As a result, mass production of liquid crystal display bodies is improved and costs can be reduced.

FIG. 2 shows another specific example of the present invention, in which 14 and 15 are glass substrates, which may be soda glass, borosilicate glass, lead glass, or any other glass substrate.

17 and 18 are polarizing plates, 19 is a reflecting plate, 16 is a liquid crystal material,
Reference numeral 20 denotes a transparent conductive film deposited on the glass substrates 14 and 15, which may be made of any material such as Sn02 or In2O3.

Reference numeral 21 denotes a circuit conductor wiring portion also deposited on the glass substrate 15, which is formed by thick film, thin film, plating, etc. made of silver, palladium, gold, nickel, copper, carbon, platinum, or oxides thereof. has been done.

22 is an IC chip (or LSI chip) that also includes a display driving function, arithmetic function, time measurement function, and other necessary circuit functions depending on various devices. It is electrically connected and adhesively fixed onto the circuit conductor wiring portion 21 via the adhesive layer 23 .

Reference numeral 24 denotes a cap for protecting the IC chip 22 from the outside world, which is also sealed and fixed with an adhesive 25 such as epoxy.

Reference numeral 26 denotes a printed circuit board for electrically connecting the liquid crystal display including the circuit section with external circuit elements (for example, a keyboard, a power supply battery, other circuit parts, etc.). It is electrically connected to the circuit wiring section 21.

In this specific example, since the circuit wiring on the display body is made of thick film, thin film, plating, etc. containing gold, silver, palladium, nickel, carbon, etc., the IC chip (LSI chip)
The reliability of the electrical connection is further improved compared to the transparent conductive films of SnO2 and In2O3.

In addition, the numerous effects mentioned above are similarly recognized.

The above-mentioned liquid crystal displays include D, S, M, display, F,
It can be applied to both E, M0 display (TN display, DAP display), and guest-host display.

Further, a particularly large effect can be obtained in fields such as calculators, watches, measuring instruments, etc., where downsizing, handyness, and cost reduction are important.

[Brief explanation of drawings]

FIG. 1 shows a first specific example of the present invention, in which 1 and 2 are glass substrates, 6 is a liquid crystal, 8 is an IC chip (or LSI chip), and 9 is a glass substrate.
7 is a conductive adhesive including a photosensitive adhesive, and 7 is a transparent conductive film. FIG. 2 shows a second specific example of the present invention, and 21 is a thick film, a thin film,
A circuit wiring part such as a plating film, 22 is an IC chip (or LS
I chip), 23 is a conductive adhesive containing a photosensitive adhesive.

Claims (1)

[Claims] 1 A liquid crystal display body consisting of at least two electrode glasses and a liquid crystal material inserted in a sandwich shape between the two electrode glasses, and a transparent electrode or thick film disposed on the electrode glass plate. A circuit wiring section made of a conductor, a thin film conductor, a plated conductor film, etc., and a display drive or arithmetic function, or both, which are directly face-down bonded onto the circuit wiring section via a conductive adhesive containing at least a photosensitive adhesive. 1. A liquid crystal display device comprising at least an IC chip having a small number of functions.