JPH09179131A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the gap between both substrates at the periphery of a liquid crystal display element uniform, suppress the generation of display unevenness at the peripheral part, and improve the display quality by nearly equalizing the occupation rate of the area of the wires at the part where a seal material is provided to the area of the seal material on each side of the liquid crystal display element, and making the total numbers of spacers present on the wires uniform respectively. SOLUTION: The seal material 3 at the entire periphery in a frame shape is considered as four divisions on each side of the liquid crystal display element 62 and the total number of spacers present on the wire 1 or 2 at the part on each side where the seal material 3 is provided is made nearly equal. Namely, the width of the seal material 3 is changed by the sides and adjusted so that the occupation rate of the area of the wires at the seal part to the area of the seal material 3 becomes nearly equal. Consequently, the dispersion rate in the seal material 3 is equal, so gap differences are suppressed on the respective sides of the liquid crystal display element 62, i.e., over the entire periphery to obtain a uniform gap, thereby suppressing the generation of display unevenness at the peripheral part of the liquid crystal display element 62.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to two transparent insulating substrates, each having a transparent electrode provided on the opposite surface thereof, superposed at a predetermined interval, and a sealing material including a large number of spacers is provided at an edge between the substrates. The present invention relates to a liquid crystal display device having a liquid crystal display element which is provided in the periphery in a frame shape, and both substrates are attached to each other by the sealing material, and liquid crystal is sealed between both substrates inside the sealing material. The present invention relates to a technique capable of uniforming a space (cell gap) between both substrates in a peripheral portion of an element.

[0002]

2. Description of the Related Art In a liquid crystal display device, for example, two transparent insulating substrates made of glass are superposed on each other with a predetermined gap so that the surfaces on which the transparent pixel electrodes for display and the alignment films are laminated face each other. A frame-shaped sealing material is provided at the edge between the two substrates to bond the two substrates together, and liquid crystal is sealed inside the sealing material between the two substrates from a liquid crystal sealing port provided in a part of the sealing material. Liquid crystal display element (that is, liquid crystal display unit; liquid crystal display panel; LCD: liquid crystal display) provided with polarizing plates on both outer sides of the substrates, and a liquid crystal display element disposed under the liquid crystal display element. A backlight that supplies light, a drive circuit board for the liquid crystal display element arranged outside the outer peripheral portion of the liquid crystal display element, and a frame-shaped body that is a molded product that holds each of these members,
Each of these members is housed, and a metal frame with a liquid crystal display window opened is included.

The liquid crystal display element and the driving circuit board are, for example, a tape carrier package (hereinafter referred to as TCP) on which a semiconductor integrated circuit chip for driving the liquid crystal display element is mounted.
It is electrically connected by. Further, in order to electrically connect the liquid crystal display element and the TCP, the lead-out wiring and the terminal of the transparent pixel electrode are formed at the end portions of the two transparent insulating substrates forming the liquid crystal display element.

Documents describing such a liquid crystal display device include, for example, JP-A-61-214548 and JP-A-2-13765.

The two transparent insulating substrates constituting the liquid crystal display element are stacked with a predetermined gap (cell gap) therebetween. To define this gap, glass, silica, plastic, A large number of small spherical or cylindrical spacers made of polymer, polystyrene or the like are interposed between both substrates. In order to arrange such spacers between the substrates, first, a large number of spacers are mixed with a liquid or gas as a medium from a spray nozzle on the entire surface of one substrate on which an alignment film subjected to an alignment treatment is formed. Sprinkle on. Then, around the edge of one substrate surface, a sealing material containing a large number of spacers having different diameters from the spacer,
It is provided in a frame shape by screen printing or coating with a dispenser. Then, the two substrates are stacked so that their alignment films face each other, and affixed with a sealing material, because a large number of spacers are interposed between the two substrates.
Both substrates are separated by a predetermined distance by the spacer. After that, liquid crystal is sealed between both substrates from a liquid crystal sealing port (a cutout portion of the sealing material) provided in a part of the sealing material, and the liquid crystal sealing port is sealed with resin to manufacture a liquid crystal display element.

References for such spacers include, for example, the '92 Liquid Crystal Display Industrial Yearbook, CMC, pages 176 to 185, pages 289 to 291 and Liquid Crystal Device Handbook, pages 257 to 263.

[0007]

Conventionally, in the manufacturing process of a liquid crystal display element, in order to form a sealing material, for example,
Screen printing is performed using a mask in which a predetermined frame-shaped seal pattern is formed on a stainless steel plate, or application is performed using a dispenser. By the way, the width of the sealing material provided in a frame shape around the edge between both substrates is
For example, it was formed with the same width as the entire circumference of about 0.4 mm.
Further, since the sealing material is crushed by superposing the two substrates, the width of the sealing material after the completion of the liquid crystal display element is about 1.0 mm.

By the way, a lead wire and a terminal for a scanning (common) electrode are provided at one end of a simple matrix type liquid crystal display element, and a data (segment) electrode is provided at an end of two opposite sides. Wiring and terminals are formed. The shape and area of the lead wire and the terminal are the same on the two opposing data electrodes, but are different between the scanning electrode and the data electrode, and the wiring on the side facing the scanning electrode terminal is the same as the other three sides. Is different.

As described above, conventionally, since the width of the sealing material formed on the wiring portion is the same all around, the sealing material is provided for the four sealing materials on each side of the liquid crystal display element. The area of the wiring in the open portion (hereinafter referred to as the seal portion), that is, the occupation ratio of the area of the wiring in the seal portion with respect to the area of the sealing material is different. Therefore, if the number of spacers dispersed per unit area in the seal material, that is, the spacer dispersion rate (dispersion density) is substantially the same, the spacers exist on the wiring of the seal portion that defines the gap in the peripheral portion of the liquid crystal display element. The number of spacers differs for each side. The occupancy rate on the data electrode terminal side facing each other is the same.

As a result, a gap difference occurs on each side of the liquid crystal display element near the sealing material. This is because the gap difference depends on the number of spacers in the seal material for forming the gap, which are present on the wiring. Conventionally, a gap difference of about 0.5 μm occurs between the data electrode terminal side and the scan electrode terminal side. Due to this gap difference, when the liquid crystal display element is turned on, display unevenness occurs in the peripheral portion of the liquid crystal display element (a large gap side looks black and a small gap side looks white), and there is a problem that display quality deteriorates.

An object of the present invention is to provide a liquid crystal display device in which the gap between both substrates in the peripheral portion of a liquid crystal display element is made uniform, the occurrence of display unevenness in the peripheral portion is suppressed, and the display quality can be improved. is there.

[0012]

In order to solve the above-mentioned problems, the present invention provides two transparent insulating substrates with transparent electrodes respectively provided on opposite surfaces thereof and superimposes the two substrates at a predetermined interval. A frame-like sealing material including a number of spacers is provided around the edge between the substrates, the substrates are bonded together by the sealing material, and liquid crystal is sealed between the substrates inside the sealing material. In the liquid crystal display device having the liquid crystal display element, the area of the wiring (transparent electrode lead-out wiring) of the portion where the sealing material is provided with respect to the area of the sealing material on each side of the liquid crystal display element. Of the spacers are made substantially equal to each other, and the total number of the spacers existing on the wiring is made substantially uniform.

Further, in order to make the area ratio of the wiring of the portion where the sealing material is provided substantially equal to the area of the sealing material, the sealing material of each side of the liquid crystal display element should be the sealing material. Adjust the width of the material. In this case, the width of the sealing material is the same on each side. Alternatively, when the width of the sealing material is substantially the same for the sealing material on each side of the liquid crystal display element, at least the area where the sealing material is provided is adjusted by adjusting the width and shape of the wiring. adjust. Further, the wiring includes a dummy electrode.

The spacer in the sealing material, which contributes to the formation of the gap in the peripheral portion of the liquid crystal display element, is the spacer existing on the wiring in the sealing portion. Since the dispersion ratio of the spacers in the sealing material is uniform, the spacers on the wiring of the sealing portion are made equal by occupying the area ratio of the wiring of the sealing portion to the area of the sealing material on each side of the liquid crystal display element. Is equal on each side, and a uniform gap can be formed. In order to make the occupation ratios equal, the width of the sealing material is changed, or at least the width or shape of the wiring of the sealing portion, that is, the area is changed on each side. As described above, in the present invention, the gap difference in the peripheral portion is suppressed and a uniform gap is obtained, so that the occurrence of display unevenness in the peripheral portion can be suppressed and the display quality can be improved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings described below, components having the same function are designated by the same reference numeral, and repeated description thereof will be omitted.

FIGS. 3A and 3B are schematic plan views showing the electrode wirings of the upper electrode substrate and the lower electrode substrate, respectively.

That is, a plurality of data driving element electrodes (also referred to as segment electrodes) are formed in parallel on the surface of a data electrode substrate (also referred to as segment electrode substrate) 12 which is two electrode substrates constituting a liquid crystal display element. Reference numeral 32 denotes a scan drive element electrode (also referred to as a common electrode) 31 formed in parallel on a surface of a scan electrode substrate (also referred to as a common electrode substrate) 11.

These two electrode substrates 11 and 12 are stacked and assembled to complete a simple matrix type liquid crystal display element (see FIG. 4). However, a plurality of electrodes are arranged in parallel on the opposing surfaces of both substrates. The electrodes 31 and 32 intersect each other at right angles when viewed from a direction perpendicular to both substrate surfaces in the completed liquid crystal display element (actually, they do not intersect, and an interlayer insulating film is interposed). Thus, one pixel is formed, that is, an effective display area is formed by the intersecting area.

FIG. 4 is a perspective view of a main part of the liquid crystal display element 62.

In FIG. 4, liquid crystal molecules are twisted between two upper electrode substrates (scan electrode substrate of FIG. 3) 11 and lower electrode substrate (data electrode substrate of FIG. 3) 12 sandwiching the liquid crystal layer 50. In order to align the layers so as to form a structure, the surfaces of the transparent upper and lower electrode substrates 11 and 12 made of glass, which are in contact with the liquid crystal, and the surfaces of the alignment films 21 and 22 made of an organic polymer resin made of polyimide, For example, a method of rubbing in one direction with a cloth, so-called rubbing method is adopted.
The rubbing direction at this time, that is, the rubbing direction, the rubbing direction 66 in the upper electrode substrate 11, the lower electrode substrate 12
In, the rubbing direction 67 is the alignment direction of the liquid crystal molecules. A gap d is formed so that the rubbing directions 66 and 67 of the two upper and lower electrode substrates 11 and 12 thus oriented may intersect each other at about 180 to 360 degrees.
_The two electrode substrates 11 and 12 are faced with each other so that they face each other, that is, a cutout portion for injecting liquid crystal, that is, a liquid crystal filling port 5
When a nematic liquid crystal having a positive dielectric anisotropy and having a predetermined amount of an optical rotatory substance added thereto is sealed by bonding with a frame-shaped sealing material 52 provided with 1, liquid crystal molecules are separated between the electrode substrates. It has a helical molecular arrangement with a twist angle of θ. Reference numerals 31 and 32 respectively denote a transparent upper electrode (scan electrode) and a lower electrode (data electrode) made of, for example, indium oxide or ITO. A member (hereinafter referred to as a birefringent member) that brings about a birefringent effect on the upper side of the upper electrode substrate 11 of the liquid crystal cell 60 configured as described above.
D retardation film ", magazine electronic material February 1991, pp. 37-41) 40, and the upper and lower polarizing plates 1 sandwiching this member 40 and the liquid crystal cell 60.
5, 16 are provided.

The twist angle θ of the liquid crystal molecules in the liquid crystal 50 can take a value in the range of 180 ° to 360 °, preferably 200 ° to 300 °, but in the vicinity of the threshold value of the transmittance-applied voltage curve. The range of 230 to 270 degrees is more preferable from the practical viewpoint of avoiding the phenomenon that the lighting state becomes an orientation that scatters light and maintaining excellent time division characteristics. This condition basically acts to make the response of the liquid crystal molecules to the voltage more sensitive and to realize excellent time division characteristics. In order to obtain excellent display quality, the product Δn of the refractive index anisotropy Δn ₁ of the liquid crystal layer 50 and its thickness d ₁ is used.
₁ · d ₁ is preferably set in the range of 0.5 μm to 1.0 μm, more preferably in the range of 0.6 μm to 0.9 μm.

The birefringent member 40 acts so as to modulate the polarization state of the light passing through the liquid crystal cell 60, and converts what could be colored display by the liquid crystal cell 60 alone into black and white display. Thus the birefringent member 40 refractive index anisotropy [Delta] n ₂ and is extremely important product [Delta] n ₂ · d ₂ of a thickness d _2, preferably 0.8μm from 0.4 .mu.m, more preferably 0.5μm To a range of 0.7 μm.

Further, since the liquid crystal display element 62 uses the elliptically polarized light due to the birefringence, the axes of the polarizing plates 15 and 16 and the optical axis thereof when the uniaxial transparent birefringent plate is used as the birefringent member 40. And the electrode substrate 11 of the liquid crystal cell 60,
The relationship between the twelve liquid crystal alignment directions 6 and 7 is extremely important.

FIG. 5 is a partially cutaway perspective view of an example of an upper electrode substrate portion of a liquid crystal display device having a color filter.

As shown in FIG. 5, red, green, and blue color filters 33R, 33G, 33B, on the upper electrode substrate 11,
By providing the light shielding film 33D between the filters, multicolor display is possible.

In FIG. 5, each filter 33 is
On the R, 33G, 33B and the light shielding film 33D, a smooth layer 23 made of an insulator is formed to reduce the influence of these irregularities, and then an upper electrode 31 and an alignment film 21 are formed.

FIG. 6 is an exploded perspective view showing a liquid crystal display module 62 in which a liquid crystal display element 62, a drive circuit for driving the liquid crystal display element 62, and a light source are compactly integrated.

The TCP 10 on which the semiconductor IC chip 34 for driving the liquid crystal display element 62 is mounted is provided with a window portion for fitting the liquid crystal display element 62 in the center, and a frame-shaped body printed with a circuit for driving the liquid crystal is formed. It is mounted on the circuit board 35. Printed circuit board 3 fitted with liquid crystal display element 62
5 is fitted into a window of a frame 42 formed of a plastic mold, a metal frame 41 is superimposed on the window, and its claws 43 are bent into cutouts 44 formed in the frame 42 to form a frame 41. Is fixed to the frame 42.

A cold cathode fluorescent tube 36 arranged at the upper and lower ends of the liquid crystal display element 62, a light guide 37 made of an acrylic plate for uniformly irradiating the liquid crystal display cell 60 with light from the cold cathode fluorescent tube 36, A reflector 38 formed by applying white paint to a metal plate and a milky white diffuser plate 39 for diffusing light from the light guide 37 are fitted into the window portion from the back side of the frame-shaped body 42 in the order of FIG. Be done. An inverter power supply circuit (not shown) for turning on the cold cathode fluorescent tubes 36 is provided with a concave portion (not shown) provided on the right rear portion of the frame member 42.
5. ). Diffusing plate 3
9, light guide 37, cold cathode fluorescent tube 36 and reflector 38
The tongue piece 46 provided on the reflection plate 38 is
It is fixed by bending it in the small edge 47 provided in the.

FIG. 7 is a plan view showing a connection state of the printed circuit board 35, the TCP 10 having the driving semiconductor IC chip 34 mounted thereon, and the liquid crystal display element 62 of the liquid crystal display device to which the present invention is applicable. .

FIG. 8 is a block diagram of a laptop personal computer using the liquid crystal display module 63 for the display portion, and FIG. 9 is a diagram showing a state in which the liquid crystal display module 63 is mounted on the laptop personal computer 64. In this laptop personal computer 64, the microprocessor 4
The result calculated in 9 is for each side of driving the liquid crystal display module 63 by the liquid crystal driving semiconductor IC chip 34 through the control LSI 48.

Embodiment 1 FIG. 1 is a simple matrix STN according to Embodiment 1 of the present invention.
(Super twisted nematic) Color liquid crystal display element corner (data electrode terminal-scanning electrode terminal)
FIG.

62 is a liquid crystal display element, 11 is a scanning (common) electrode substrate, 12 is a data (segment) electrode substrate,
31 is a scan drive element electrode, 32 is a data drive element electrode,
Reference numeral 1 is a scan electrode terminal, 2 is a data electrode terminal, 3 is a sealing material, 4a, 4b and 4c are dummy electrodes provided to make the cell gap uniform, S ₁ is a width of the sealing material on the scanning electrode terminal side, and S _{2 is} Is the width of the sealing material on the data electrode terminal side.

In this embodiment, the seal material 3 is provided by screen printing between the transparent insulating substrate 12 with the data electrodes and the transparent insulating substrate 11 with the scanning electrodes. In the present embodiment, the frame-shaped sealing material 3 around the entire circumference is used as the liquid crystal display element 62.
For each side, the wiring is divided into four parts. Regarding the sealing material 3 on each side, the wiring 1 or 2 at the portion where the sealing material 3 is provided.
Spacers existing above (not shown; for example, diameter 8-9 μ
occupancy of the wiring area of the seal portion with respect to the area of the seal material 3 (total area of wiring in the seal portion divided into four / area of the seal material) The width of the sealing material 3 was changed and adjusted for each side so that the respective values were substantially equal. That is, for example, the sealing material width S ₁ on the scanning electrode terminal side
Is about 0.34 mm, the sealing material width S _{2 on the two} data electrode terminal sides facing each other is about 0.4 mm, and the sealing port (not shown here) on the side opposite to the scanning electrode terminal 1 is on the side. It was formed to about 0.36 mm. As a result, since the spacers in the sealing material 3 have the same dispersion ratio (for example, 300 pieces / 1 mm ² ), generation of a gap difference is suppressed on each side of the liquid crystal display element 62, that is, the entire circumference, and a uniform gap is obtained.
The occurrence of display unevenness in the peripheral portion of the liquid crystal display element 62 is suppressed,
The display quality in the peripheral area was improved. Further, in the present embodiment, since only the pattern change of the seal pattern mask in screen printing is required, the implementation is very easy.

Second Embodiment FIG. 2 is a simple matrix STN according to a second embodiment of the present invention.
It is a plan view of a corner portion (data electrode terminal-scanning electrode terminal portion) of the color liquid crystal display element.

In the present embodiment, the sealing material 3 having a uniform width of about 0.4 mm is formed between the transparent insulating substrate 12 with the data electrodes and the transparent insulating substrate 11 with the scanning electrodes by screen printing or by coating with a dispenser. It is provided in. In this embodiment, regarding the sealing material 3 on each side of the liquid crystal display element 62, the wiring 1 at the portion where the sealing material 3 is provided
2 so that the total number of spacers (not shown) existing above 2 is substantially equal to each other, that is, the occupation ratio of the wiring area of the seal portion to the area of the sealing material 3 is substantially equal to each other. As described above, at least the dummy electrodes 4a, 4b, 4c of the portion where the sealing material 3 is provided
The width, shape, or area of the lead-out wiring 1 or 2 including the above was changed and adjusted. That is, for example, the occupancy rate on the scan electrode terminal side is about 74.6%, the occupancy rate on the data electrode terminal side is about 64.3%, and the filling port on the side opposite to the scan electrode terminal 1 (see FIG. 4).
The occupancy rate on the side of 51) was about 70.7%. As a result, since the spacers in the sealing material 3 have the same dispersion rate, a uniform gap is obtained on each side of the liquid crystal display element 62, and the occurrence of display unevenness in the peripheral portion of the liquid crystal display element 62 is suppressed, and the peripheral portion is suppressed. The display quality in was improved. Further, in the present embodiment, the width of the sealing material 3 is the same all around, which is advantageous when the sealing material 3 is formed using a dispenser. In the present embodiment, when adjusting the area occupancy of the wiring, the shape is devised as shown in the lower left part of FIG. 2 so that the resistance of each lead wiring becomes equal. The occupancy rate is usually about 60 to 70%, and the difference in occupancy rate on each side of the liquid crystal display element 62 is preferably within about 5%.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. . For example, on the surfaces of the transparent insulating substrates 11 and 12 where the sealing material 3 is provided, wiring (transparent electrode lead-out wiring, dummy electrode) is usually formed on either substrate surface, but the cell gap is uniform. For the purpose of, for example, in the portion where the sealing material 3 is provided, wiring may be provided on one substrate surface and a dummy electrode may be formed on the other opposing substrate surface according to the shape of the wiring. Of course, the present invention can be applied to the case. in this case,
On each side of the liquid crystal display element 62, the occupation ratio of the area of the seal portion wiring and the dummy electrode overlapped with respect to the area of the seal material 3 is made substantially uniform, and the wiring portions on both substrate surfaces of the seal portion are respectively made. And the total number of spacers existing between the dummy electrodes is made substantially uniform. Further, in the first embodiment shown in FIG. 1, the width of the sealing material 3 is made equal on each side, but it is not always necessary to do so. Further, in the above-mentioned embodiment, an example of application to a simple matrix type liquid crystal display device is shown, but the present invention is not limited to this and is also applicable to an active matrix type liquid crystal display device using a thin film transformer or the like as a switching element. is there.

[0038]

As described above, according to the present invention,
The gap between both substrates in the peripheral portion of the liquid crystal display element becomes uniform, so that the occurrence of display unevenness in the peripheral portion can be suppressed and the display quality can be improved.

[Brief description of the drawings]

FIG. 1 is a simple matrix STN according to a first embodiment of the present invention.
It is a plan view of a corner portion (data electrode terminal-scanning electrode terminal portion) of the color liquid crystal display element.

FIG. 2 is a simple matrix STN according to a second embodiment of the present invention.
It is a plan view of a corner portion of a color liquid crystal display element.

3A and 3B are schematic plan views showing electrode wirings of an upper electrode substrate and a lower electrode substrate, respectively.

FIG. 4 is an exploded perspective view of an example of a liquid crystal display element to which the present invention can be applied.

FIG. 5 is a partially cutaway perspective view of an example of an upper electrode substrate portion of a color liquid crystal display device to which the present invention is applicable.

FIG. 6 is an exploded perspective view of an example of a liquid crystal display module to which the present invention can be applied.

FIG. 7 is a TCP in which a printed circuit board and a driving semiconductor IC chip are mounted in a liquid crystal display device to which the present invention is applicable.
FIG. 3 is a plan view showing a connection state with the liquid crystal display element.

8 is a block diagram of an example of a laptop personal computer in which the liquid crystal display module of FIG. 6 is mounted as a display unit.

9 is a perspective view of an example of the laptop computer of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scan electrode terminal, 2 ... Data electrode terminal, 3 ... Seal material, 4a, 4b, 4c ... Dummy electrode, 11 ... Scan (common) electrode substrate, 12 ... Data (segment) electrode substrate,
31 ... Scan electrode, 32 ... Data electrode, 62 ... Liquid crystal display element, S ₁ ... Width of sealing material on scanning electrode terminal side, S ₂ ... Width of sealing material on data electrode terminal side.

Claims (5)

[Claims] 1. A transparent electrode is provided on each of opposing surfaces of two transparent insulating substrates, the two substrates are overlapped with a predetermined space therebetween, and a sealing material including a large number of spacers is provided around an edge between the two substrates. A liquid crystal display device having a liquid crystal display element, which is provided in a frame shape on the substrate, is bonded to the both substrates by the sealing material, and liquid crystal is sealed between the both substrates inside the sealing material. In the liquid crystal display device, the occupying ratio of the area of the wiring of the portion where the sealing material is provided to the area of the sealing material of the sealing material on each side is substantially equal. 2. The liquid crystal display device according to claim 1, wherein a width of the sealing material is adjusted with respect to the sealing material on each side of the liquid crystal display element so that the occupancy rates are substantially equal to each other. 3. The liquid crystal display device according to claim 2, wherein the width of the sealing material is equal on each side. 4. With respect to the sealing material on each side of the liquid crystal display element, the widths of the sealing materials are substantially the same, and at least the area of the wiring at the portion where the sealing material is provided is adjusted, A liquid crystal display device, wherein the occupancy ratios are substantially equal to each other. 5. The liquid crystal display device according to claim 1, wherein the wiring includes a dummy electrode.