WO1996025687A1

WO1996025687A1 - Liquid crystal display element

Info

Publication number: WO1996025687A1
Application number: PCT/JP1996/000347
Authority: WO
Inventors: Masamichi Yamauchi; Yasuhiro Imai
Original assignee: Citizen Watch Co., Ltd.
Priority date: 1995-02-17
Filing date: 1996-02-16
Publication date: 1996-08-22

Abstract

A liquid crystal display element having at least two transparent glass substrates each having in turn a transparent electrode that are disposed such that the transparent electrodes disposed in the respective substrates confront each other with a space given therebetween, wherein liquid crystal is provided in this space, seals being provided so as to prevent the leakage of liquid crystal, and a driving circuit for driving the liquid crystal being disposed on the substrates outside the seals, the liquid crystal display element being characterized in that a first light shielding member having a light absorbing member for absorbing light is provided below the driving circuit via the transparent glass substrate.

Description

Description Liquid crystal display device Technical field

The present invention relates to a liquid crystal display element used for a liquid crystal television, a liquid crystal monitor, a liquid crystal projector, and the like.In particular, the present invention relates to a case where an IC as a drive circuit for driving a liquid crystal display element malfunctions due to light. The present invention relates to a liquid crystal display element that has been prevented. Background art

In recent years, liquid crystal display devices have been used in many fields such as information processing devices, televisions, watches, mobile phones, and the like. Generally, a liquid crystal display element is driven by a static drive method in which all segment electrodes are individually driven, or a multiple drive method in which all the segment electrodes are divided into a plurality of sets and time-division driven. There is a box drive system. Regardless of the driving method, the driving circuit is disposed in the vicinity of the liquid crystal display element in the form of Ic. The drive circuit basically consists of a selection circuit that selects rows and columns of elements arranged in a matrix, a scanning circuit that scans these elements, and a hold circuit that temporarily stores data. Is performed. These circuits have been integrated into IC for further miniaturization. However, smaller circuits are more susceptible to light.

By the way, inevitable light from the liquid crystal display element arrives at the drive circuit. That is, light propagating inside the display element itself and light generated by the backlight.

However, as described above, liquid crystal display devices are used in a great many fields. It may cause problems in actual use because it is used. For example, when the camera flashes directly above the liquid crystal display element, or when the IC as a drive circuit is operated under an electric light or under sunlight. Since such a situation can occur on a daily basis, it is necessary to take measures to prevent malfunctions even against such external light. Disclosure of the invention

An object of the present invention is to provide a liquid crystal display device having an improved display quality by preventing an IC as a drive circuit disposed very close to the liquid crystal display device from malfunctioning due to external light or internal propagation light. To provide.

According to the present invention, a transparent glass substrate provided with at least two transparent electrodes is provided such that the transparent electrodes provided on each substrate face each other and have a gap, In a liquid crystal display device having a structure in which a liquid crystal is provided in this gap and a seal is provided so that the liquid crystal does not leak, and an IC for driving the liquid crystal is provided on a substrate outside the seal. In addition, a first light-blocking member having a light-absorbing member that absorbs light is provided below the IC via the transparent glass substrate.

As a preferred embodiment, a second surface having a light reflecting member for reflecting light on one side and a light absorbing member for absorbing light on the other side below the IC via the transparent glass substrate. O It is characterized by a configuration in which a light shielding member is arranged.

In a further preferred embodiment, the light absorbing member is made of a black nonwoven fabric or a black polyester cross. Further, an adhesive is provided on the surface of the light absorbing member.

Further, the adhesive is composed of a rubber-based material, a silicone-based material, or a resin-based material. Furthermore, the light reflecting member is made of aluminum foil.

In a further preferred embodiment, a third shield covering the IC and its periphery is provided. An optical member is further provided, and the third light shielding member is made of a silicon resin or the same as the first or second light shielding member.

Further, a fourth light-blocking member is further provided around the IC and between the frame having a display window and the transparent glass substrate on the IC side, and the fourth light-blocking member is made of a sponge or rubber-based material. It is made of an elastic material.

Further, a fifth light-blocking member is provided between the side surface of the IC, the transparent glass substrate, and the frame having the display window, and the fifth light-blocking member is made of a sponge or rubber-based elastic member. It is composed of materials.

Further, a sixth light shielding member is provided between the transparent glass substrate at the end of the first or second light shielding member and the frame having the display window, and the sixth light shielding member is a sponge. It is made of a di- or rubber-based elastic material. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a liquid crystal display device showing a third embodiment of the present invention.

FIG. 4 is an explanatory view in which the first or second light-blocking member of the present invention is actually arranged on the IC around the liquid crystal display element.

FIG. 5 shows a fourth embodiment of the present invention.

FIG. 6 shows a fifth embodiment of the present invention.

FIG. 7A shows a sixth embodiment of the present invention.

FIG. 7 (B) is a detailed configuration diagram of the light shielding member of FIG. 7 (A).

FIG. 8A shows a seventh embodiment of the present invention.

FIG. 8 (B) is a detailed configuration diagram of the light blocking member of FIG. 8 (A). FIG. 9 shows an eighth embodiment of the present invention.

FIGS. 10 (A) to (D) are explanatory diagrams of the effect of the present invention.

Fig. 11 is a partial cross-sectional view of a typical conventional color LCD device.

FIG. 12 is a cross-sectional view of a conventional COG liquid crystal display device. BEST MODE FOR CARRYING OUT THE INVENTION

Prior to the description of the best mode for carrying out the present invention, the related art and its problems will be described below.

FIG. 11 is a partial cross-sectional view of a conventional typical color liquid crystal display device. The conventional liquid crystal display element 110 will be described below.

In FIG. 11, on the surface of one of the transparent substrates, a glass substrate 112, a light-shielding film 111, a color filter 113, and a protective film 111 are formed on a color filter 113. A pixel electrode 115 formed of a transparent conductive film is formed thereon. Further, an alignment layer 116 for aligning liquid crystal molecules is formed on the pixel electrode 115. On the surface of the other transparent glass substrate 117, a pixel electrode 118 formed of a transparent conductive film and an alignment layer 119 are formed thereon, and both substrates are sealed by a seal 150. They are stuck together. The thickness of the liquid crystal 122 (the distance between the opposing alignment films, the space 124 between the liquid crystal display elements 110) is mainly determined by the spacer 120 in the liquid crystal. The spacer 120 is sprayed on one of the substrates substantially uniformly in advance before the two substrates are bonded to each other.

The pixel electrodes 115 are drawn out of the seal 150 as wiring electrodes for driving the liquid crystal. In the seal 150, a spacer 151 in the seal is provided, and together with the spacer 120 in the liquid crystal, the size of the gap 124 between the liquid crystal display elements 110 is determined. I have. The protective film 114 is for protecting the color filter 113 and flattening the surfaces of the color filter 113 and the light shielding film 111.

Conventionally, as a liquid crystal display element, for example, as disclosed in Japanese Utility Model Application Laid-Open No. 6-89336, a liquid crystal in which an IC as a drive circuit for driving the liquid crystal is disposed on a transparent glass substrate is used. There is a display element. In addition, as a method of disposing an IC on the transparent glass substrate, for example, Japanese Utility Model Laid-Open No. 6-89336, Japanese Patent Laid-Open No. Hei 6-112272, Japanese Utility Model Laid-Open No. A method called C 0 G (Chip On Glass) in which an IC (drive circuit chip) is mounted on a transparent glass substrate as disclosed in Japanese Patent No. There is a method in which a logic element is formed by a thin film transistor (TFT), which is disclosed in Japanese Patent Publication No. 17 and has been commercialized, to form a drive circuit.

The present invention can be applied to any of the above-described liquid crystal drive circuit mounting methods. However, since the use of COG has a particularly remarkable effect, the following prior art will be described with respect to the COG method.

FIG. 12 is a cross-sectional view of a conventional COG liquid crystal display device. In FIG. 12, a pixel electrode 115 is provided on a transparent substrate 112 made of a glass material. The transparent substrate may be a substrate made of a plastic material. Further, a lead electrode 13 1 for connecting a drive circuit and a pixel electrode is provided on the glass substrate 112. An IC 130 as a drive circuit is connected to an end of the lead electrode 13 1. Although not shown, a lead electrode for inputting and outputting signals to and from the liquid crystal display element is provided from another terminal of the IC 130 connected to the lead electrode 13 1. Then, the input / output lead electrodes are connected to the external circuit of the liquid crystal display element using a conductive adhesive or a connector.

The glass substrate 117 also has the same configuration as that of the glass substrate 112, and is provided with a lead electrode for connecting the IC and the pixel electrode 118. The end of the lead electrode is connected to Ic as a drive circuit. These are not shown in the drawing because they are in the depth direction. The substrates 112 and 117 configured as described above are opposed to each other with a certain gap by a spacer 120 in the liquid crystal and a spacer 151 in the seal. Further, a substantially peripheral portion of the substrate is sealed by the seal 150, the liquid crystal is injected into the gap, and the injection port is sealed to form the liquid crystal display element 110.

The conductive layer 13 2 is for reinforcing or lowering the resistance of the lead electrode 13 1. Whether or not to provide the conductive layer 132 may be arbitrarily determined depending on various conditions.

By the way, in the above-mentioned conventional technology, when external light or internally propagating light is applied to the IC as a driving circuit, IC malfunction occurs due to bit inversion or the like inside the IC, and as a result, display quality is reduced. The problem of lowering has been reduced.

Therefore, when the cause of the IC malfunction was investigated in detail, as shown in Fig. 12, light 161 or light 162 propagated inside the transparent glass substrate, and the periphery of the IC bump (lead electrode and It was found that these lights jumped into the IC and caused malfunctions.

That is, generally, a lighting device such as a fluorescent tube, a light guide member, an LED, an EL, a high-brightness lamp, or the like is provided below the liquid crystal panel. As a result, various lights enter the IC, resulting in malfunction due to bit inversion of the internal memory of the IC and the like, and furthermore, a problem of deteriorating the display quality of the liquid crystal display element.

An object of the present invention is to eliminate the above-mentioned cause of the IC malfunction due to external light or internal propagation light and to obtain a liquid crystal display element having good display quality.

FIG. 1 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention. FIG. 2 is a sectional view of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 3 is a sectional view ^{5 of} a liquid crystal display device according to a third embodiment of the present invention.

In the following description, only the light absorbing member will be referred to as a first light blocking member, and a member having a light absorbing member and a light reflecting member will be referred to as a second light blocking member. Also, the same components as those in the conventional technology are denoted by the same reference numerals.

In FIG. 1, which is a first embodiment of the present invention, a pixel electrode 115 is provided on a substrate 112, which is a transparent substrate made of glass or a plastic material, and an IC is connected to the pixel electrode. A lead electrode 1311 is provided, and an end of the lead electrode 13 1 is connected to an IC 13 which is a drive circuit. Although not shown, a lead electrode for inputting / outputting a signal to / from the liquid crystal display element from another terminal of the IC connected to the lead electrode 13 1 is provided. In addition, the input / output lead electrodes are connected to the external circuit of the liquid crystal display element 110 using a conductive adhesive or a connector.

The substrate 1 17 has the same configuration as that of the substrate 1 12 described above. The substrate 1 17 is provided with a lead electrode 14 1 for connecting the IC to the pixel electrode 1 18, and an IC 1 as a drive circuit is provided at an end of the lead electrode 14 1. 40 is connected (see Fig. 4).

The substrates 112 and 117 having the above configuration are opposed to each other with a certain gap by a spacer 120 in the liquid crystal and a spacer 1515 in the seal. Further, a substantially peripheral portion of the substrate is sealed by the seal 150, a liquid crystal is injected into the gap, and the injection port is sealed to form a liquid crystal display element.

The conductive layer 132 is for reinforcing or lowering the resistance of the lead electrode 131, and whether or not it is provided may be arbitrarily determined according to various conditions. In FIG. 1, a second light-blocking member 10 is provided on a substrate surface facing the IC 130 with the substrate 112 interposed therebetween. Shielding member 10 is the surface of the board From the side, an adhesive material, black polyester (light absorbing member), and aluminum foil (light reflecting member) are arranged in this order. However, in actual use, these components are configured as a single sheet with a single layer of eyebrows, improving workability. That is, it is configured as a light-shielding tape having a predetermined width, cut into a predetermined length, and disposed on a substrate surface facing the IC 130 with the substrate 112 interposed therebetween.

According to the configuration shown in FIG. 1, the light propagating through the transparent glass substrate (see 16 1 and 16 2 in FIG. 12) is absorbed by the light absorbing member composed of black polyester, and the IC 13 It is possible to prevent light from entering from the zero substrate surface. On the other hand, light from outside of the IC 130 is totally reflected by the aluminum foil provided on the upper surface of the light shielding member 10, and is prevented from entering the periphery of the IC bump.

Resin-based or rubber-based silicone-based materials can be used as the adhesive forming a part of the light shielding member 10.

As the black polyester constituting the light absorbing member, soft vinyl, polyethylene, glass, paper, or the like can be used as a film-like nonwoven fabric or a cloth.

On the other hand, the light reflecting member may be made of any material such as the above-mentioned aluminum foil, such as white or silver, and may have a sealing effect, and may be made of aluminum or a thin steel plate.

Since the thickness of these light-shielding members is as thin as 0.1 mm to 0.5 mm, they are suitable for liquid crystal display elements that require thinness.

In FIG. 2, which is a second embodiment of the present invention, a first light-shielding member 11 made of a light-absorbing member is provided on a substrate surface facing the IC 130 with the substrate 112 interposed therebetween. ing. The light-blocking member 11 is composed of an adhesive material and a black polyester (light-absorbing member) in this order from the substrate side. In actual use, it is configured as a single sheet to improve workability. . According to the configuration of FIG. 2, light transmitted through the transparent substrate is absorbed by the black polyester, which is a light absorbing member, and can prevent light from entering from the surface of the glass substrate 112 of the IC 130. it can.

In FIG. 3, which is a third embodiment of the present invention, a first light blocking member 12 (light absorbing member) is provided on a surface of the substrate facing the IC 130 with the substrate 112 interposed therebetween. The light-shielding member 12 is made of a black light-absorbing paint applied to the substrate surface, and is obtained by applying a matte paint, a poster color, or a black resin to the substrate.

According to the configuration of FIG. 3, light traveling through the transparent glass substrate is absorbed by the light absorbing member, and light can be prevented from entering from the substrate surface of the IC 130.

In the embodiment of the present invention described above, the light-blocking member 10 (11, 12) is provided at a portion facing the IC 13 with the substrate 1 12 interposed therebetween. As explained, the above I

By arranging a similar light-shielding member in combination with the light-shielding member below C, more stable operation of IC can be obtained.

FIG. 4 is a front view in which the first or second light-blocking member of the present invention is actually arranged on the IC. As shown in the drawing, the light-blocking member 10 (11, 12) is disposed on the back side of the IC 130 as shown by a dotted line. On the other hand, for the IC 140, the light-shielding member 10 (11,

1 2) is installed on the front side. Reference numerals 112 and 117 denote glass substrates, and thin-line portions denote liquid crystal display elements.

FIG. 5 shows a fourth embodiment of the present invention. By covering the IC side with, for example, a silicone resin as a third light-blocking member, external light is reflected on the surface of the glass substrate, and This prevents light from entering the IC element surface on the bump side. As shown, the first or second light-blocking member 10 (11, 12) is provided via the glass substrate 112. Have been. The ICI 30 is covered with a silicone resin 160 as a third light shielding member. Silicon resin 160 has a color that absorbs or reflects light. For example, it is configured by mixing a black pigment or a black powder in a silicon resin.

FIG. 6 shows a fifth embodiment of the present invention. In the example of FIG. 5, the IC side is covered with a silicone resin, but in this example, the light shielding tape 170 (light shielding member) used in FIGS. 1 to 3 is used. 10, 11, and 12) are also arranged on the IC side.

FIG. 7 (A) is a sixth embodiment of the present invention, and FIG. 7 (B) is a detailed configuration diagram of the light shielding member of FIG. 7 (A). In this example, a fourth light shielding member 180 is provided between a glass substrate 117 and a frame 210 by a sponge, rubber, or the like. As a result, light (see the arrow) arriving at the IC 130 from outside the frame 210 can be blocked. As shown in FIG. 7B, a light-blocking member 180 having a sponge or rubber-based light-absorbing color is integrally formed in a frame shape.

FIG. 8A is a seventh embodiment of the present invention, and FIG. 8B is a detailed configuration diagram of a light shielding member. This is an example in which a sponge or rubber-based fifth light shielding member 190 is provided on the IC side. As shown, a fifth light-blocking member 190 is provided between the IC 130, the glass substrate 117, and the frame 210.

FIG. 9 shows an eighth embodiment of the present invention, in which a first or second light-shielding member 10 (11, 12) has a sixth light-shielding member 2 made of sponge or rubber. This is an example where 0 is provided. As shown in the figure, a sixth light-shielding member 200 is disposed between the side surface of the first or second light-shielding member 10 (11, 12) and the frame 210. Thus, light arriving at the IC from outside can be blocked.

FIGS. 10 (A) to 10 (D) are diagrams for explaining the effects of the present invention. FIG. 5 is an explanatory diagram of effects of the first embodiment shown in FIGS. In this experiment, it is determined whether the display on the LCD screen is normal (OK) or abnormal (NG) when the camera flash is applied from above the LCD panel. At this time, the distance between the liquid crystal display surface and the flash is changed variously, and the angle is changed to make the determination. In addition, the effect when the size of the light-shielding tape is changed is also determined. The samples used in this experiment were as follows: Sample A: Aluminum vapor deposition on the upper surface, black on the lower surface, thickness 50 a Sample B: black light-shielding tape, thickness 50

Sample C: No light shielding tape

It is. Sample A is a light-shielding tape relating to the second light-shielding member of the present invention, sample B is a light-shielding tape relating to the first light-shielding member of the present invention, and sample C is a conventional light-shielding tape.

(A) is a case where the camera flash is applied directly above the liquid crystal display surface, and the distance from the liquid crystal display surface to the flash is 40, 30, 25, 20, 30. This is the case where it is changed to 15 cm. In the figure, "OK" indicates that the IC operated normally and no abnormality appeared on the liquid crystal display, and "NG" indicates that the IC malfunctioned and an abnormality appeared on the liquid crystal display. As shown in the figure, in Sample A of the present invention, when the flash was approached to 15 cm, the result was NG, and in Sample B, it was NG at 25 cm.In the conventional example of Sample C, it was 30 cm without the light-shielding tape. Is NG.

(B) is a case where the flash is applied at an angle of 45 ° from the liquid crystal display surface. The distance from the liquid crystal display surface to the flash is the same as (A). As shown in the figure, both Sample A and Sample B of the present invention were NG at 20 cm and no difference was observed, whereas Sample C of the prior art was NG at 30 cm.

(C) and (D) are judgments of the effect of changing the size of the light-shielding tape with respect to the sample A of the present invention, and (C) is the effect on the liquid crystal display surface. This is the case where the camera's flash is applied directly above, and (D) is 45 from the liquid crystal display surface. This is the case when flash was applied at an angle of. The distance from the liquid crystal display surface to the flash is the same as in (A).

In the case of (C), if the size is the same as the size of IC, NG is obtained at 25 cm. However, if the size is 0.5 mm or more larger than the size of IC, NG is obtained at 15 cm. On the other hand, in the case of (D), if it is larger than the IC size by 0.7 mm or more, it becomes NG at 15 cm. From these results, when the camera flash is applied directly above the liquid crystal display surface, it is effective if the light-shielding tape size is larger than 0.5 mm, and it is effective at an angle of 45 ° from the liquid crystal display surface. When flash is applied, it is effective if the size of the light-shielding tape is 0.7 mm or more.

From the above experimental results, in (A), the effect is inferior to that of sample A because the light from the front (flash light) penetrates the black tape of sample B because the effect is remarkable in sample A. In this case, the effect gradually appears as the thickness of the light-shielding tape is increased, but there is a hindrance when incorporating it into a module in actual use, and the thickness is limited.

In (B), since the flash light impinges obliquely, the light often propagates inside the liquid crystal display element. In this case, since the light propagating inside the glass of the liquid crystal display element is made black to absorb the light, the difference between sample A and sample B is hardly observed.

Furthermore, for (C) and (D), a remarkable effect can be obtained if the size of the light-shielding tape is 0.7 mm or more with respect to the IC size.

The present invention provides a transparent glass substrate by disposing a light-shielding member on the bump side of an IC via a glass substrate, and further adding a light-shielding member such as silicon resin to the IC side. To the bump side of the IC In addition to preventing light from entering, it also has the effect of preventing light from directly entering the bump-side surface of the IC. This eliminates the cause of IC malfunction and has the effect of obtaining a liquid crystal display device with good display quality. Industrial applicability

According to the present invention, it is possible to prevent the IC as a drive circuit disposed near the liquid crystal display element from malfunctioning due to external light or internal propagation light and to improve the display quality. It is very effective in various application fields, such as liquid crystal televisions, liquid crystal monitors, liquid crystal projectors, etc., that use, and has great industrial applicability.

Claims

The scope of the claims

1. A transparent glass substrate on which at least two transparent electrodes are disposed is disposed such that the transparent electrodes disposed on each substrate face each other with a gap, and a liquid crystal is disposed in the gap. A liquid crystal display element having a configuration in which a seal is provided so as not to leak liquid crystal and a drive circuit for driving liquid crystal is provided on the substrate outside the seal. A liquid crystal display device comprising: a first light-blocking member having a light-absorbing member for absorbing light disposed below a drive circuit.

2. A transparent glass substrate on which at least two transparent electrodes are disposed is disposed such that the transparent electrodes disposed on each substrate face each other with a gap, and a liquid crystal is disposed in the gap. A liquid crystal display element having a configuration in which a seal is provided so as not to leak liquid crystal and a drive circuit for driving liquid crystal is provided on the substrate outside the seal. A liquid crystal display having a configuration in which one surface has a light reflecting member for reflecting light and the other surface has a second light shielding member having a light absorbing member for absorbing light, below the drive circuit. Display element.

3. The liquid crystal display device according to claim 1, wherein the light absorbing member is made of a black nonwoven fabric.

3. The liquid crystal display device according to claim 1, wherein the light absorbing member is made of black polyester cross.

5. The liquid crystal display device according to claim 1, wherein an adhesive is provided on a surface of the light absorbing member.

6. The liquid crystal display device according to claim 5, wherein the adhesive is made of a rubber-based material, a silicone-based material, or a resin-based material.

7. The liquid crystal display device according to claim 2, wherein the light reflecting member is made of aluminum foil.

8. The liquid crystal display device according to claim 1, further comprising a third light blocking member that covers the drive circuit and its periphery.

9. The liquid crystal display device according to claim 8, wherein the third light shielding member is made of a silicon-based resin.

10. The liquid crystal display device according to claim 8, wherein the third light-blocking member is formed of the same material as the first or second light-blocking member.

11. A fourth light-shielding member is further provided around the drive circuit and between a frame having a display window and a transparent glass substrate on the drive circuit side. Or the liquid crystal display element according to 2.

12. The liquid crystal display device according to claim 11, wherein the fourth light-blocking member is made of a sponge or a rubber-based elastic material.

13. The claim 1 or 2, wherein a fifth light-blocking member is provided between a side surface of the drive circuit, a transparent glass substrate, and a frame having a display window. Liquid crystal display element.

14. The liquid crystal display device according to claim 13, wherein the fifth light shielding member is made of a sponge or a rubber-based elastic material.

15. A sixth light-blocking member is provided between a transparent glass substrate at an end of the first or second light-blocking member and a frame having a display window. 3. The liquid crystal display device according to 2.

16. The liquid crystal display device according to claim 15, wherein the sixth light shielding member is made of a sponge or a rubber-based elastic material.