JPH10293315A - Transparent substrate sticking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly irradiate a sealing agent intervened between an upper and a lower substrates with an ultraviolet ray without making it transmit through the transparent substrates. SOLUTION: An ultraviolet irradiation device 40 for hardening a sealing agent 4 provided between transparent substrates 1, 2 is composed of an optical fiber bundle and the incidence end includes a light guide 41 facing an ultraviolet radiation lamp, while the outgoing end of the light guide 41 divided into four and made flat is inserted into a slit 42a formed on each side of a square framed holder 42 with a cylindrical lens 43 fitted to each side on the inner side surface of the holder 42 causing the four sides to be irradiated by a fine slit light inward of the holder 42 and the whole sealing agent 4 is hardened by irradiating the surface of the transparent substrates 1, 2 toward the sealing agent 4 intervened between the transparent substrates 1, 2 positioned inside the holder 42 with slit light containing an ultraviolet ray in the direction parallel to the surface of the transparent substrates 1, 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to manufacturing a liquid crystal panel as a display unit of a liquid crystal display device.
The present invention relates to a transparent substrate bonding apparatus for bonding a pair of upper and lower transparent substrates with a certain gap.

[0002]

2. Description of the Related Art A liquid crystal panel as a display portion in a liquid crystal display device has a pair of transparent substrates, and at least one of these transparent substrates has an electronic circuit element such as a transistor and a transparent electrode on at least one of the transparent substrates. A color filter and the like are stacked on the other transparent substrate. Liquid crystal is sealed between the two transparent substrates, a sealant is supplied near the outer peripheral edge portion, and the sealant is irradiated with ultraviolet rays to be cured. Here, the gap between the two transparent substrates must be strictly adjusted. If there is a variation in the size of the gap, inconveniences such as uneven brightness of the screen occur. For this purpose, glass beads having a predetermined particle size are arranged almost entirely between the upper and lower transparent substrates, and the beads are made to function as spacers when the upper and lower transparent substrates are bonded to each other. However, in the case of a small liquid crystal panel, a sealer is filled with a spacer, but generally, a member functioning as a spacer is not sealed in the display portion.

In such a small liquid crystal panel as described above, substrate pressing means for holding a pair of upper and lower transparent substrates by vacuum suction are provided vertically, and one of the transparent substrates is provided near an outer peripheral edge thereof. In a state where the sealant is applied to a predetermined thickness on the part, the two transparent substrates are respectively held by the pressing means, and in a state where they are aligned with each other, the transparent substrates are moved in a direction approaching each other. By displacing, the sealant adheres to the other transparent substrate. Then, by applying a predetermined pressing force between the two transparent substrates, the sealing agent is crushed by a predetermined amount so as to bond together with a predetermined gap secured between the two transparent substrates. Further, in this state, the sealant is cured by irradiating the sealant with ultraviolet rays, so that the two transparent substrates are fixed in a bonded state. Here, the irradiation of the ultraviolet rays is made to pass through either the upper or lower transparent substrate to irradiate the sealant.

[0004]

By the way, when irradiating ultraviolet rays to cure the sealant, the transparent substrate is made to pass through when the ultraviolet rays are irradiated, so that the portion of the transparent substrate to which the ultraviolet rays are irradiated becomes transparent. It must be ensured that the sealing agent is not covered by a pressing means or the like. Generally, in a liquid crystal panel, in order to remove harmful light from a backlight, it is necessary to provide a light shielding portion having a predetermined width in a frame shape near the outer peripheral edges of upper and lower transparent substrates. Therefore, the ultraviolet irradiation part for curing the sealant is located outside the light shielding part on the transparent substrate. Therefore, a transparent portion having a predetermined width must be formed outside the light shielding portion. In addition, at the time of bonding the two transparent substrates, a predetermined pressing force is applied, and the sealing agent is crushed, so that the width of the sealing agent is widened. Dimensions must be set in anticipation of the widening of the width. As described above, when configured as a liquid crystal panel, there is a problem that an extra area is increased by the width of the transparent portion necessary only for curing the sealant, and the liquid crystal panel becomes larger than necessary. Further, there is also a problem that a pressing region when the substrate is pressed by the pressing unit is limited, and the arrangement of each mechanism including the pressing unit is greatly restricted.

The present invention has been made in view of the above points, and an object of the present invention is to directly apply ultraviolet light to a sealant interposed between upper and lower transparent substrates without transmitting the transparent substrates. To be able to irradiate.

[0006]

In order to achieve the above-mentioned object, the present invention is directed to a method in which a pair of upper and lower transparent substrates in which liquid crystal is sealed are placed near an outer peripheral edge with a certain gap therebetween. Pressing means for clamping the transparent substrate by irradiating ultraviolet rays to the provided sealant to cure the two transparent substrates, and clamping the upper and lower transparent substrates from above and below, while adjusting the gap between the upper and lower transparent substrates, An ultraviolet irradiation means for irradiating ultraviolet rays between the transparent substrates held by the pressurizing means is provided.

Here, as a specific configuration of the ultraviolet irradiation means, a slit for projecting light is provided on each side of a rectangular frame-shaped member, and the exit end of a light guide made of an optical fiber is provided in each of these slits. It is preferable to face the light guide, and if a condenser lens is provided in front of the light emitting end of the light guide, the directivity of the irradiated ultraviolet light is improved, and the irradiation efficiency of the ultraviolet light to the sealant is increased. . Further, the pressure means can be provided with a gap adjusting means for one of the transparent substrates, and the gap adjusting means is constituted by a plurality of adjusting projections abutting on the transparent substrate. It is preferable to adopt a configuration in which the substrate is vacuum-adsorbed to the transparent substrate and can be displaced in a direction approaching and separating from the transparent substrate. In order to perform the gap adjustment, it is necessary to detect the gap between the two transparent substrates. However, this gap detection means can be constituted by an interferometer unit, and this interferometer unit is provided on the side facing the gap adjustment means. You can do so.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 shows two transparent substrates 1 and 2 constituting a liquid crystal panel. The lower transparent substrate 1 has a large number of electrodes 3 drawn out on the surface side thereof, and at least a portion where the electrodes 3 are drawn out has a size protruding from the end of the upper transparent substrate 2.
Note that the lower substrate 1 may be configured to protrude in three directions. A liquid crystal panel is formed by bonding the two transparent substrates 1 and 2, and a sealing agent 4 is used for the bonding. As the sealant 4, an epoxy resin-based ultraviolet-curing type is used. This sealant 4 is applied in a frame shape around the outer periphery of one transparent substrate, for example, the transparent substrate 1, and is partially applied. An opening 4a for enclosing the liquid crystal is formed.

In bonding the transparent substrates 1 and 2, the transparent substrates 1 and 2 are image-recognized with reference to alignment marks (not shown) formed on the outer peripheral portions of the transparent substrates 1 and 2. And the relative position is adjusted. This positioning may be performed at the bonding stage. However, after the mutual positioning is performed at the positioning station, the transparent substrates 1 and 2 are temporarily fixed via the sealing agent 4 and are then carried into the bonding station. Then, bonding can be performed.

FIG. 2 shows a schematic configuration of an entire bonding apparatus for bonding the transparent substrates 1 and 2. As is apparent from this figure, the upper pressing means 10 has a pair of upper and lower pressing means 10 and 11.
A pad 12 made of an elastic member such as rubber is adhered to the lower surface of the device, and a pad 13 is adhered to the upper surface of the lower pressing means 11. These pads 12,1
Numerals 3 are in contact with positions substantially corresponding to each other in the vicinity of the outer periphery of the transparent substrates 1 and 2, preferably in contact with the position where the sealant 4 is applied, so that pressure can be applied from above and below. Then, the transparent substrates 1 and 2 are pressed by the upper and lower pressing means 10 and 11 in a direction approaching each other. However, the sealing agent 4 contains beads functioning as spacers. 2 are kept separated by the thickness of the beads.

In the state where the pressure is applied by the pressing means 10 and 11 as described above, the gap is adjusted first. This gap adjustment is for adjusting the gap between the portions of the transparent substrates 1 and 2 inside the portion filled with the sealant 4, that is, the portion where the liquid crystal is sealed, to be constant. For this purpose, the sealing agent 4 of the transparent substrate 1 is applied to the lower pressing means 11.
A predetermined number of gap adjusting means 20 are provided so as to cover almost the entire inside of the portion surrounded by. This gap adjusting means 20 has, for example, the configuration shown in FIG. In the figure, reference numeral 21 denotes an operating part, which has a substantially spherical tip and is disposed so as to protrude from the upper surface of the pressing means 11 by a predetermined length. A large-diameter stopper portion 21a is continuously provided at the base end of 21. Further, an actuator 22 made of a piezoelectric element or the like is fixedly provided on the stopper portion 21a. The actuator 22 is fixedly provided on a bottom surface of the recessed portion 23 provided in the pressurizing means 11. I have. Therefore, by applying a voltage to the actuator 22, the operating piece 21 can be displaced in the vertical direction.

A through hole 24 penetrating vertically is formed in the center of the operating portion piece 21, and a through hole 25 is similarly provided in the actuator 22.
Reference numerals 4 and 25 are formed in the pressurizing means 11 and communicate with a suction passage 26 connected to a negative pressure source. Therefore, the transparent substrate 1 can be sucked by applying a negative pressure to the suction passage 26 while the operating portion 21 is in contact with the transparent substrate 1. Then, in this state, the actuator 22
When the voltage applied to the transparent substrate 2 is changed, the operating portion piece 21 pushes the transparent substrate 1 upward or downward, thereby adjusting the gap between the transparent substrate 2 and the transparent substrate 2. The actuating members 21 constituting the gap adjusting means 20 are regularly arranged at an inner portion where the sealant 4 is applied, whereby the gap between the transparent substrate 1 and the transparent substrate 2 is partially formed. Even if they are different, they are configured so that they can be adjusted to be uniform.

In order to operate the gap adjusting means 20 to adjust the gap, the gap must be detected in advance. For this purpose, the upper pressurizing means 10 is formed in a frame shape, and an interferometer 30 is fixedly provided therein. As shown in FIG. 4, the interferometer 30 has a laser light source 31 and a condenser lens 32 for condensing the laser light from the laser light source 31.
The light condensed in 2 passes through the pinhole 33 to remove harmful light. The light passing through the pinhole 33 diverges while being diverged.
4 and is reflected by the reflection surface 34 of the beam splitter 34 to be converted into a parallel light beam by the collimator lens 35. A part of the parallel light from the collimator lens 35 is reflected on the upper transparent substrate 2, and the light transmitted through the transparent substrate 2 is reflected on the surface of the transparent substrate 1.
The light reflected on the surface of the transparent substrate 2 and the light reflected on the surface of the transparent substrate 1 pass through the beam splitter 34 while mutually interfering with each other. The apparatus is configured to be captured by an imaging unit 37 via the imaging unit 37 so that interference fringes can be photographed by the imaging unit 37.

On the basis of the interference fringe information obtained by the imaging means 37, if an interference fringe is generated at a central portion, for example,
It is detected that the uniformity of the gap has been impaired, such as whether the gap at the center is narrower or wider. Therefore, the operating portion 21 of the gap adjusting means 20 located at the center is driven by the actuator 22 so that the tip of the operating portion 21 abuts on the transparent substrate 1 to slightly push up this portion. As a result, whether the gap is widened or narrowed is determined depending on whether the number of interference fringes is reduced or increased. Therefore, when the gap is wide, the transparent substrate 1 is pushed up by the operating piece 21, and when the gap is narrow, the transparent substrate 1 is sucked and pulled down by the operating piece 21 when the gap is narrow, thereby forming a predetermined gap. Is adjusted as follows. When the interference fringes partially appear, the gap is adjusted by pushing up or down by the operating piece 21 located at or near the site where the interference fringes appear. When the above operation is performed and the interference fringes are substantially eliminated from the image obtained by the imaging unit 37, the gap between the transparent substrates 1 and 2 is in a uniform state as a whole. Let it cure.

In order to cure the sealant 4, an ultraviolet irradiation device 40 shown in FIG. 5 is used. The ultraviolet irradiation device 40 has a light guide 41 made of an optical fiber bundle, and the incident end of the light guide 41 faces the ultraviolet irradiation lamp, though not shown, and the emission end is divided into four parts. It is flattened and inserted through slits 42a formed on each side of the rectangular frame-shaped holder 42. Further, a cylindrical lens 43 is mounted on each side of the inner surface of the holder 42, so that narrow slit light is irradiated on the four sides inward of the holder 42.

By configuring the ultraviolet irradiation device 40 as described above, the transparent substrates 1 and 2 are positioned inside the holder 42, and the ultraviolet light is emitted from the light guide 41 toward the sealing agent 4 interposed therebetween. The slit light can be emitted from a direction parallel to the surfaces of the transparent substrates 1 and 2. As a result, the sealant 4 is directly irradiated with ultraviolet rays and cured, so that the transparent substrates 1 and 2 are assembled in a state where they are fixed to each other. Moreover, since the light emitting end of the light guide 41 is flattened and the light is condensed by the cylindrical lens 43, the directivity of the ultraviolet rays to the sealant 4 is extremely high, and the ultraviolet rays are effectively and efficiently applied to the sealant 4. UV light can be irradiated. The ultraviolet rays penetrate inward from the surface of the sealant 4 facing the light guide 41, so that the sealant 4
The whole is cured smoothly.

As described above, the ultraviolet rays are irradiated directly from the space between the transparent substrates 1 and 2 toward the sealant 4 without passing through the transparent substrate. Can irradiate ultraviolet rays without interference. Therefore, the pressurizing means 10 and 11 can be arranged at positions where the sealant 4 on the transparent substrates 1 and 2 is covered, and a uniform pressing force can be applied to the entire sealant 4. As a result of this pressurization, the sealant 4 is squashed and spreads, but the sealant 4 spreads in a substantially uniform width to make the inside of the liquid crystal sealed uniformly and completely. be able to.

Further, when a liquid crystal panel is configured, its display surface is limited to remove harmful light due to reflection of illumination light from a backlight. For this,
A light-shielding portion is provided at a portion on the outer peripheral side of the transparent substrates 1 and 2. However, when the sealant 4 is irradiated with ultraviolet rays through the transparent substrate, the transparent portion must be formed outside the light-shielding portion. Must. However, since the ultraviolet rays are directly applied to the sealant 4, the transparent substrates 1, 2
There is no need to provide a transparent portion on the outer peripheral side of the light-emitting device, and the light-shielding portions 5 and 6 can be formed up to the outer peripheral edge as shown in FIG. Therefore, the liquid crystal panel as a whole can be reduced in size, and the amount of the sealant 4 applied can be increased to further improve the sealing property inside the liquid crystal.

[0019]

As described above, according to the present invention, in a state where the gap between the upper and lower transparent substrates is adjusted, the upper and lower sides are clamped from above and below by the pressing means, and are substantially parallel to the surface of the transparent substrate from the ultraviolet irradiation means. Irradiate with ultraviolet light in a certain direction,
Because it was configured to directly cure the sealant with ultraviolet light,
Ultraviolet rays can be directly radiated to the sealing agent interposed between the upper and lower transparent substrates without passing through the transparent substrate, and the sealing agent is effectively and efficiently cured without being interfered by other members or the transparent substrate. It has effects such as being able to do.

[Brief description of the drawings]

FIG. 1 is an external view showing upper and lower transparent substrates constituting a liquid crystal panel.

FIG. 2 is an apparatus configuration diagram for adjusting a gap between upper and lower transparent substrates and curing a sealant with ultraviolet rays.

FIG. 3 is a cross-sectional view illustrating a configuration of a gap adjusting mechanism.

FIG. 4 is an explanatory diagram of a configuration of an interferometer for performing gap detection.

FIG. 5 is a schematic configuration diagram of an ultraviolet irradiation device.

[Explanation of symbols]

Reference Signs List 1, 2 Transparent substrate 4 Sealant 10, 11 Pressurizing means 20 Gap adjusting means 21 Actuating piece 22 Actuator 30 Interferometer 40 Ultraviolet irradiation device 41 Light guide 42 Holder 43 Cylindrical lens

Claims (5)

[Claims] 1. A pair of upper and lower transparent substrates in which liquid crystal is sealed between the pair of transparent substrates by irradiating ultraviolet rays to a sealant provided in the vicinity of an outer peripheral edge of the pair of transparent substrates with a predetermined gap therebetween. In a state in which the gap between the upper and lower transparent substrates is adjusted, pressing means for clamping from above and below, and irradiating ultraviolet rays toward the gap between the two transparent substrates held by the pressing means A transparent substrate bonding apparatus, comprising: 2. The ultraviolet irradiating means is provided with slits for projecting light on each side of a rectangular frame-shaped member so that each of the slits faces an emission end of a light guide made of an optical fiber. 2. The apparatus for bonding transparent substrates according to claim 1, wherein a condensing lens is provided in front of an emission end of the light guide to condense light toward a sealant between the transparent substrates. 3. The apparatus according to claim 1, wherein said pressurizing means is provided with a gap adjusting means for one of the transparent substrates. 4. The gap adjusting means comprises a plurality of adjustment projections abutting on the transparent substrate, and the adjustment projections are vacuum-adsorbed to the transparent substrate and moved in a direction of approaching and separating from the transparent substrate. 4. The apparatus for bonding transparent substrates according to claim 3, wherein the apparatus is configured to be displaceable. 5. The transparent substrate according to claim 3, wherein an interferometer unit is provided on a side facing said gap adjusting means in order to detect a gap between said transparent substrates. Laminating device.