JP2003255362A - Cell and its production method and liquid crystal optical element using the cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide small-sized cells made by precisely splitting glass substrate and a production method thereof. <P>SOLUTION: This liquid crystal cell is formed by sticking a pair of substrates with a gap via the seal composed of an outer peripheral seal part for sticking a pair of the substrates, end parts formed by cutting off one part of the outer peripheral seal part and an injection port part which communicates the inside and outside of a pair of the substrates from both of the end parts. This cell is further constituted in such a manner that at least one part of the outer peripheral seal part is split together with a pair of the substrates by the scribe and break method. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell and a method for manufacturing the same, and particularly to a cell in which a glass substrate is optimally cut vertically and a method for manufacturing the same, when a liquid crystal cell is required to be downsized. The present invention relates to a liquid crystal optical element using the cell.

[0002]

2. Description of the Related Art A small liquid crystal cell is manufactured in consideration of mass productivity.
Two large glass substrates are bonded together via a sealant to integrally form a plurality of cells, which are then cut into elongated strip-shaped substrates for liquid crystal injection and sealing. After that, the strip-shaped substrate is cut to manufacture individual liquid crystal cells.

This glass substrate is cut by a scribing process in which a glass cutter made of cemented carbide or diamond is used to make a cut in the surface of the glass substrate and a breaking process in which the substrate is pressure-divided along the vertical cracks generated at this time. A single liquid crystal cell is obtained by cutting.

Next, a method of manufacturing a cell by the conventional scribe break method will be described. 1 (a)-(d)
FIG. 7 is a schematic process cross-sectional view for explaining the conventional scribe / break method. As described above, a large number of cells are formed at one time, but a single cell is shown in an enlarged scale here for ease of explanation.

First, as shown in FIG. 1A, a large-sized glass substrate 1 and a glass substrate 2 each having a transparent electrode 3 made of indium tin oxide (ITO) formed thereon are bonded together by using a sealing material to form a cell. It is formed. Here, the transparent electrode 3 provided on the glass substrate 1 and the glass substrate 2 becomes an active area for operating the liquid crystal 6 injected into the gap. Next, a notch 71 having a predetermined depth is made on the glass substrate 1 with a glass cutter at a predetermined distance from the end of the outer peripheral seal portion 5 formed by the scribing method, and the structure shown in FIG. Get the body. Next, the substrate is turned upside down, and a notch 72 is similarly made in the glass substrate 2 by a scribe method to obtain the structure shown in FIG. 1 (b). Next, an impact force is applied from the opposite side of the notch 71 by the breaking means 8 to extend the crack 9 to obtain the structure of FIG. 1 (c). Further, the substrate is turned upside down, and a tensile stress due to an impact force is applied from the opposite side of the notch 72 by the breaking means to extend the vertical crack. As a result, the liquid crystal cell can be manufactured by cutting the glass substrates 1 and 2 to manufacture the cell of FIG. 1D, injecting the liquid crystal, and sealing the injection port.

The lower part of FIG. 2 is a conceptual cell sectional view for explaining the fractured cross-sectional shape of the glass substrate when only the glass substrate 1 is fractured by the conventional scribe-break method. The cut surface of the glass substrate cut by the conventional scribe-break method is the scribe position (position A) in the glass substrate.
As a reference, the glass substrate is obliquely cut away from the outer peripheral seal portion 5. The cause is the sealing material 5
This is because the glass substrate 1 and the glass substrate 1 are fairly firmly fixed to each other and the stress distribution inside the glass substrate becomes uneven in the depth direction of the glass substrate due to the influence of the adhesive force. Therefore,
By the break means performed after scribing, the crack bends and extends, and the fractured surface of the glass substrate 1 is obliquely fractured. It can be easily inferred that this tendency becomes more remarkable as the position A is closer to the seal 5.

The upper diagram of FIG. 2 shows the scribe position of the glass substrate 1 (distance A in the lower diagram of FIG. 2) cut by the conventional scribe-break method and the glass substrate 1 actually cut from the scribe position of the glass substrate 1. 3 is a graph showing the relationship between the measured distances to the end faces (distance B in the lower diagram of FIG. 2). Reference numeral 100 in this graph is data obtained by actually measuring the distance A and the distance B after forming the structure shown in the lower diagram of FIG. 2, and reference numeral 102 is the distance A and the distance B.
It is an ideal straight line when are equal. That is, if this ideal straight line is taken, it indicates that the glass substrate 1 is vertically cut by the scribe break method. The horizontal axis in the upper diagram of FIG. 2 is the distance A from the end of the outer peripheral seal portion 5 to the scribe position.
(Unit is μm), and the vertical axis represents the distance B from the end of the outer peripheral seal portion 5 to the end of the glass substrate (cutting dimension, unit: μm).
m) is shown. According to the upper diagram of FIG. 2, in order to manufacture a liquid crystal cell having a vertical fractured surface without being affected by the adhesive force between the seal and the glass substrate, the position A for vertically breaking the glass substrate 1 is sealed. It is necessary to be separated from the end by 170 μm or more, and it is understood that if the position A is cut closer to the seal side than that, the glass substrate is cut obliquely.

Next, as another conventional method, a method of manufacturing a cell by the half-cut dicing break method will be described. 3A to 3D are process cross-sectional views for explaining a cell manufacturing method according to the method.

According to this method, water must be used as a grinding liquid for dicing during processing. But,
Mixing water and impurities into the cell causes defects, so make sure that water and impurities do not enter the cell.
The processing of the glass substrate before liquid crystal injection and sealing is performed by providing an outer ring seal on the outer periphery of the glass substrate 1 and the glass substrate 2 and then forming a grinding groove by half-cutting with a dicing grindstone and then breaking. Must be manufactured. The process will be described step by step.

First, the glass substrate 1 is half-cut dicing with a dicing grindstone, and a grinding groove 81 is inserted.
The structure of (a) is obtained. Here, for the above-mentioned reason, the half cut is essential so that the grinding fluid is not mixed in the cell. Further, an outer ring seal 85 is provided on the outer periphery of the glass substrate 1 and the glass substrate 2 so that the grinding liquid does not enter the cell. Next, the glass substrate is turned upside down, the glass substrate 2 is diced in the same manner as the glass substrate 1, the grinding groove 82 is formed, and the structure shown in FIG. 3B is obtained. Next, an impact force is applied from the opposite side of the grinding groove 81 by the breaking means 8 to cleave the bottom of the grinding groove 81 to obtain the structure of FIG. 3 (c). Next, the glass substrate is turned over, an impact force is applied to the grinding groove 81 by a breaking means, and the glass substrate 2 is also cut to obtain the structure shown in FIG. 3 (d).

[0011]

As is clear from the above description, the scribe-break method has a simple apparatus configuration and can be processed in a short time. In order to cut, a margin of at least the following dimensions is required at the board design stage. That is, the dimensions are at least a seal printing accuracy of about 100 μm on one side, a reproducibility error of the seal width of each cell when forming a large number of cells at a time of about 100 μm, and a positioning error of the scribing device of about 30 μm. The distance required to make the fractured surface vertical is about 170 μm or more. These dimensions (margin in board design) occupy about 400
This size is not negligible in making a small cell having an active area of, for example, about 3 mm.

In the half-cut dicing break method, the width of the half-cut portion formed by dicing is
The grinding wheel width becomes 150 to 300 μm, and FIG.
As is clear from (d), the grinding means after the half-cutting becomes a fractured surface protruding from the glass substrate by the break means. The protrusions not only pose a problem when miniaturizing the cell, but also cause microcracks, which cause the glass substrate to be partially chipped off from the microcracks, resulting in a marked deterioration in cell quality.

As described above, in order to manufacture a small cell by the conventional method, the accuracy of the cell cutting is not sufficient, and the protrusion is always formed on the fractured surface, so that the above problems can be solved. The current situation is not. An object of the present invention is to solve the above problems and provide a small cell in which a glass substrate is accurately cut and a method for manufacturing the same.

[0014]

In order to achieve the above object, the present invention basically employs the technique as described below. That is, the first means for solving the above-mentioned problems in the present invention is to provide an outer peripheral seal portion for bonding a pair of substrates, an end portion where a part of the outer peripheral seal portion is cut out, and a pair of end portions. A substrate in which the pair of substrates are bonded together with a gap interposed therebetween through a seal formed of an injection port that communicates the inside and the outside of the substrate, and at least a part of the outer peripheral seal portion together with the pair of substrates is a scribe-break method. It is a structure that is divided by.

A second means is a constitution in which a non-hygroscopic member is applied to at least a part of the sealing surface of the cell in which the seal is cut. A third means is that the non-hygroscopic member is made of an epoxy-based acrylic resin.

Further, a fourth means is to connect the inside and outside of the pair of substrates from the outer peripheral seal portion for bonding the pair of substrates, the end portion where a part of the outer peripheral seal portion is cut out, and the both end portions. The method employs a step of bonding the pair of substrates with a gap therebetween through a seal having a pouring portion, and a manufacturing method of cutting at least a part of the outer peripheral seal portion by a scribe-break method. Also,
A fifth means employs a manufacturing method including a step of applying a non-hygroscopic member to at least a part of the sealing surface of the cell in which the seal has been cut, after the manufacturing method of the fourth means.

Further, a sixth means for forming a liquid crystal optical element using the cell is to apply the cell described in any one of the means 1 to 3.

Here, the "cutting" of the present invention means a scribing process for making a score on the surface of a glass substrate and a process of pressing the substrate along the vertical cracks generated by pressing along the vertical cracks generated at this time. It means a substrate dividing method including a break step of pressure dividing.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A cell of the present invention and a method for manufacturing the same will be described below with reference to the drawings. First, as in the conventional process, as shown in FIG. 4, the glass substrate 1 and the glass substrate 2 are
An electrode is provided for forming a plurality of cells. A quartz plate or the like can be used instead of the glass substrate. In this embodiment mode, the glass substrate is white plate glass having a thickness of 0.4 mm, and the electrodes are formed of ITO.

After that, an alignment film (not shown) of polyimide is formed by a printing method, baked at 100 ° C., and then subjected to an alignment treatment by a rubbing method of rotating and pressing a roll around which a cloth is wound. Thereafter, spacers for maintaining a uniform cell gap are scattered on the glass substrate 1, and a sealant for enclosing the liquid crystal is printed at a predetermined position on the glass substrate 2 with a width of 0.4 to 0.5 mm, for example. . In the embodiment of the present invention, the spacers are made of plastic beads of 5 μm, and the sealing material is made of thermosetting resin.

Next, the glass substrate 1 and the glass substrate 2 are bonded to each other and baked under pressure to form a large number of cells in the same substrate. The pressure is an important condition for determining the thickness unevenness of the completed liquid crystal cell, and here,
It was pressure-fired at 0.5 kg / cm ² . The firing temperature was 150 ° C. in a nitrogen atmosphere. Needless to say, this optimum firing temperature varies depending on the material of the sealing material.

Next, cell division will be described. As shown in FIG. 5, in a glass substrate on which a large number of cells were arranged, cuts were made on the injection port 21 side and the opposite side of the cells with a glass cutter, and scribe lines 22 and scribe lines 23 were provided respectively. At this time, seal the IT
A cut is made based on the position of the scribe mark 24 formed by O. The width of the seal after the pressurization and firing is about 1.5 mm. That is, since the cell is formed by stacking a pair of glass substrates and applying pressure, the seal width at the time of printing (for example, about 0.4 to 0.5 mm) is about 3 to 4 when the cell is completed. This is because the size will be doubled (about 1.5 mm).
Therefore, as a dimension width narrower than that, for example, 0.8 mm
When it is desired to form cells having a seal width of about a certain extent, it is necessary to print the seal-printing step to a size of about 0.2 mm. It is extremely difficult to print a seal with such a narrow width with good reproducibility with the current printing accuracy.

Therefore, in the present invention, as described below, after a seal having a width of 1.5 mm is formed once, a position separated by 170 μm or more from the outer shape of the seal, which has been a problem in forming a miniaturized cell. It was possible to form a miniaturized cell by cleaving the glass substrate directly above the seal instead of cleaving the glass substrate. The process will be described in detail below.

6 (a) to 6 (d) are schematic process sectional views for explaining the cleaving of the glass substrate on which the cell is formed according to the present invention. FIG. 6A is a cross-sectional view of the cell at a stage where the glass substrate 1 located right above the outer peripheral seal portion 5 in the cell is scribed and the notch 71 is made unlike the conventional process. The notch 71 is located at a position 0.8 mm from the outermost portion of the electrode 3 that drives the liquid crystal, and corresponds to almost the central portion of the outer peripheral seal portion 5. The scribe conditions vary greatly depending on the material of the substrate to be cleaved, but in the present embodiment, a carbide wheel is used as the glass cutter, the cutting depth is 0.2 mm, and the pressing pressure of the glass cutter using the air cylinder is It was performed at 0.2 kg / cm ² .

Next, as shown in FIG. 6B, the bonded glass substrate is turned upside down, and the glass substrate 2 is also scribed right above the outer peripheral seal portion in accordance with the scribe mark.
Make a notch 72. The scribe conditions are the same as for the first glass substrate.

Next, as shown in FIG. 6C, the notch 7
An impact force is applied from the side opposite to 1 by the breaking means 8 to extend the crack 9 in the glass substrate 1.

Next, as shown in FIG. 6 (d), the bonded substrates are turned upside down, and an impact force is applied by a breaking means from the side opposite to the notch 72 to make the glass substrate 1 and the glass substrate 2
And cleave at the same time.

When this cell is used as a liquid crystal cell, a strip-shaped substrate in which a plurality of cells for injecting and sealing liquid crystal are arranged in a line is obtained as shown in FIG. A liquid crystal is injected into this strip-shaped substrate by a vacuum injection method and sealed with a UV-curable sealing agent. Then, based on the position of a scribe mark (not shown) arranged so as to cut the sealed portion of the cells arranged in a line, a cut is made along the scribe line 25 in the glass substrate. The scribe conditions may be the same as the above-mentioned conditions. Note that a plurality of strip-shaped substrates may be arranged and scribed at the same time. Subsequent break conditions are the same as in the step of manufacturing the strip-shaped substrate, and a small liquid crystal cell can be obtained from a large-sized substrate formed in a large number. Further, in the above-mentioned process, the method of injecting the liquid crystal after forming the strip-shaped substrate is shown, but the liquid crystal may be injected after breaking the strip-shaped substrate into a single piece.

(Example 1) Next, an optical pickup of a DVD will be described as an application example using the liquid crystal cell of the present invention as a liquid crystal optical element with reference to FIG. FIG. 8 is a block diagram showing the overall configuration of an optical pickup when the liquid crystal cell of the present invention is used as a liquid crystal optical element. The optical pickup shown in FIG. 8 includes a laser light source 31, a collimator lens 32, a polarization beam splitter 33, a liquid crystal cell 34 as aberration correction means, a quarter-wave plate 35, an objective lens 36, a condenser lens 38, and a light receiver. And 39. In FIG. 8, the laser light emitted from the laser light source 31 enters the liquid crystal cell 34 after passing through the polarization beam splitter 33. The liquid crystal cell 34 is a light modulation element having a function of modulating a laser beam passing through the cell to correct aberration. After that, the light passes through the quarter-wave plate 35 and is focused on the disk 37 by the objective lens 36. The light beam reflected by the disk 37 passes through the objective lens 36 and the quarter-wave plate 35 again, has its optical path changed by the polarization beam splitter 33, and is converged by the light receiver 39 through the condenser lens 38. .

The optical pickup applied to this DVD is required to be particularly small, and in order to realize the small optical pickup, it is necessary to make the outer shape of the liquid crystal cell as small as possible. Therefore, if the present invention is applied to the liquid crystal cell used for this optical pickup, the miniaturization of the liquid crystal cell can be easily achieved.

Next, the structure of a specific embodiment of the liquid crystal cell according to the present invention will be described with reference to FIG. FIG. 9 (upper diagram) is a diagram of the liquid crystal cell viewed from the laser light irradiation direction.
FIG. 9 (lower diagram) is a schematic cross-sectional view taken along the line AA of FIG. 9 (upper diagram), and particularly shows the cell gap, the spacer material, and the conductive particles in an enlarged manner.

The liquid crystal cell shown in FIG. 9 includes a transparent first glass substrate 13 and a transparent second glass substrate 15, respectively. The first glass substrate 13 has the first transparent electrode 12 and the external terminal electrode 43, and the second glass substrate 15 is provided with the second transparent electrode 14. An aberration correction pattern 60 for correcting the aberration by modulating the laser light by the first transparent electrode 12 and the second transparent electrode 14 is formed. The first transparent electrode 12 and the second
An alignment film (not shown) was provided on the transparent electrode 14 of, and the alignment directions of the alignment films were parallel to each other.

The glass substrate 13 and the second substrate thus configured
Glass substrate 15 of the first transparent electrode 12 and the second transparent electrode 12
The transparent electrodes 14 are placed in parallel with each other and are bonded by a sealing material. Further, this liquid crystal cell has an outer peripheral seal portion 5 formed of a sealant, and injection ports 5a and 5b for communicating the inside and the outside of the pair of glass substrates from both ends of the outer peripheral seal portion 5. In addition, a spacer 16 is mixed in the outer peripheral seal portion 5 so that the glass substrate 1
3 and the second glass substrate 15 were adhered to each other while keeping a predetermined gap.

In addition, the first glass substrate 13 and the second glass substrate 13 are formed from the liquid crystal inlet formed by the pair of inlets 5a and 5b.
The nematic liquid crystal 11 was sealed in the space between the glass substrate 15 and the injection port was sealed with the sealing agent 94.

In the embodiment of the present invention, in order to reduce the width in the vertical direction of the liquid crystal cell of FIG. 9 (upper diagram), the upper and lower opposite sides of the outer peripheral seal portion 5 are sealed with the first glass substrate. 13 and the second glass substrate 15 are “cut”. In this way, the step of cleaving the outer peripheral seal portion 5 can reduce the seal width and, as a result, the width of the liquid crystal optical element.

Further, as described above, since the outer peripheral seal portion 5 is formed by the screen printing method, it is difficult to form a thin seal. That is, it is difficult to form a seal having a narrow width of about 0.5 to 0.8 mm from the accuracy of the apparatus if the side surface of the seal formed by the screen printing method is accurately linear. Therefore, in order to reduce the width of the liquid crystal optical element, the glass substrate 13 and the second
A small liquid crystal optical element was obtained by breaking the seal together with the glass substrate 15.

In the embodiment of the present invention, the sealing agent 94 for sealing the liquid crystal inlet formed by the pair of inlets 5a and 5b is moved to one side so as not to enter the effective diameter 95. It was possible to form a liquid crystal cell of further miniaturization.

(Embodiment 2) The outer peripheral seal portion 5 of the liquid crystal cell used as an optical element also uses a sealant having moisture resistance, similar to the seal of a normal liquid crystal panel.
However, in order to reduce the size of the liquid crystal optical element, that is, to reduce the width of the liquid crystal optical element, a part of the outer peripheral seal portion 5 is used.
If the width of the outer peripheral seal portion 5 is reduced too much, the moisture permeation resistance may decrease. In that case, it is desirable to apply a non-moisture absorbing member made of an epoxy-based acrylic member to the fractured surface of the seal (not shown) to improve the moisture permeation resistance.

[0039]

As is apparent from the above description, according to the present invention, a cell having a good outer shape accuracy is obtained by cutting at least a part of the outer peripheral seal portion for bonding a pair of substrates by the scribe break method. It was possible to provide the manufacturing method.

Further, by cutting at least a part of an outer peripheral seal portion of a liquid crystal optical element manufactured by adhering two transparent substrates having transparent electrodes and the like through a seal with a gap, a small liquid crystal optical element. The device could be provided.

[Brief description of drawings]

FIG. 1 is a schematic process cross-sectional view for explaining a conventional cell manufacturing method by a scribe-break method.

FIG. 2 is a graph in which the aiming position of a scribe and the distance actually cut when actually cut by the conventional scribe-break method are measured, and the sectional shape of the cell when only the glass substrate is cut by the method. It is a cell schematic sectional drawing for explaining.

FIG. 3 is a process cross-sectional view for explaining a cell manufacturing method by a conventional half-cut dicing break method.

FIG. 4 is a perspective view of a substrate for explaining a stage where a transparent electrode and a seal are formed on a glass substrate according to the embodiment of the present invention.

FIG. 5 is a perspective view of a substrate for explaining cell division according to the embodiment of the present invention.

FIG. 6 is a process cross-sectional view for explaining the cleaving of the glass substrate according to the embodiment of the present invention.

FIG. 7 is a perspective view of a substrate for explaining the formation of a liquid crystal cell according to the embodiment of the present invention.

FIG. 8 is a schematic diagram of a device configuration when the liquid crystal cell of the present invention in Example 1 is applied to an optical pickup using a liquid crystal optical element.

9A and 9B are a plan view and a cross-sectional view for explaining the configuration of the liquid crystal optical element of the present invention in Example 1.

[Explanation of symbols]

1, 2 glass substrate 5 Perimeter seal part 5a, 5b inlet part 8 break means 9 crack 11 nematic liquid crystal 12 First transparent electrode 13 First glass substrate 14 Second transparent electrode 15 Second glass substrate 21 Inlet 22,23 scribe line 24 scribe marks 31 laser light source 32 Collimating lens 33 Polarizing beam splitter 34 Liquid crystal cell 35 1/4 wave plate 36 Objective lens 37 discs 38 Condensing lens 39 light receiver 43 External connection terminal 60 Aberration correction pattern 71,72 notches 94 Sealing agent 95 effective diameter

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H089 HA14 HA17 KA01 KA10 LA02                       LA12 LA13 LA16 LA18 LA21                       LA22 LA41 MA03Y MA03Z                       NA55 PA13 QA02 QA12 QA13                       QA16 TA01 TA06 UA05 UA09                 2H090 JA11 JB02 JB03 JB11 JC02                       JC12 JD12 JD15 LA03                 4G015 FA03 FA04 FB02 FC01 FC10                       FC14

Claims (6)

[Claims] 1. A seal composed of an outer peripheral seal portion for bonding a pair of substrates, an end portion in which a part of the outer peripheral seal portion is cut out, and an injection port portion for communicating the inside and the outside of the pair of substrates from the both end portions. A cell in which the pair of substrates are bonded to each other with a gap interposed therebetween, wherein at least a part of the outer peripheral seal portion is cut together with the pair of substrates by a scribe-break method. 2. The liquid crystal cell according to claim 1, wherein a non-hygroscopic member is applied to at least a part of the sealing surface of the cell where the seal is cut. 3. The cell according to claim 2, wherein the non-hygroscopic member is an epoxy-based acrylic resin. 4. An outer peripheral seal portion for bonding a pair of substrates, a terminal portion in which a part of the outer peripheral seal portion is cut out, and an injection port portion for communicating the inside and outside of the pair of substrates from the both terminal portions. And a step of bonding the pair of substrates with a gap therebetween with a seal, and a step of cleaving at least a part of the outer peripheral seal portion by a scribe-break method. 5. The cell manufacturing method according to claim 4, further comprising a step of applying a non-hygroscopic member to at least a part of a seal surface of the cell obtained by breaking the seal. Method. 6. A liquid crystal optical element comprising the cell according to any one of claims 1 to 3.