JP2009216786A - Liquid crystal element and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal element capable of restraining to the utmost a seal from entering into an inner area when overlapping two transparent substrates, and to provide a manufacturing method therefor. <P>SOLUTION: A groove is formed along a seal shape in an inner position formed with a frame-like seal, in at least one of the two transparent substrates, in the liquid crystal element layered to be overlapped with the two transparent substrates via the frame-like seal, and arranged with a liquid crystal in the inner area of the frame-like seal, and the frame-like seal is arranged in an area ranging from a position flowing into the groove up to an outside, or an area coating the groove and extended to both sides of an inside and an outside of the groove. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal element and a method for manufacturing the same, and more particularly to a liquid crystal element in which the shape of an inner region of a seal does not become larger than necessary and a method for manufacturing the same.

  Currently, liquid crystal elements are used in various applications, and there is an optical pickup device as an application of the liquid crystal elements. This optical pickup device is used for irradiating an optical disc with laser light emitted from a laser light source, condensing reflected light from the optical disc, reading information on the optical disc, and writing information on the optical disc. . In this optical pickup device, a liquid crystal optical element is used to correct the wavefront aberration of laser light (see, for example, Patent Document 1).

  The external shape of the liquid crystal element used in this optical pickup device is very small, about several millimeters square. In the future, with further miniaturization of the optical pickup device, it is inevitable that a liquid crystal element having a smaller outer shape will be required.

  Therefore, a method for manufacturing a liquid crystal element that can be applied to a liquid crystal element having a small external size has been disclosed (see, for example, Patent Document 2).

  First, here, the configuration of the liquid crystal element described in Patent Document 2 is shown in FIG. FIG. 8A is a cross-sectional view of this conventional liquid crystal element, and FIG. 8B is a plan view of the liquid crystal element.

  As shown in FIGS. 8A and 8B, the conventional liquid crystal element 20 has two transparent substrates 2a and 2b overlapped with a predetermined gap through a frame-shaped seal 3, and the gap In addition, the liquid crystal 4 is arranged in the inner region of the frame-shaped seal 3. Here, in the liquid crystal element 20 having a reduced outer size, the effective diameter 6 is a region where the laser light incident on the element passes through the liquid crystal element 20. The opening diameter of the frame-shaped seal 3 of the liquid crystal element 20 is formed larger than the effective diameter 6, and the distance from the inner wall of the frame-shaped seal 3 to the effective diameter 6 is 7 b.

  Next, a method for manufacturing the conventional liquid crystal element 20 will be described. 9 and 10 are views showing a conventional method for manufacturing a liquid crystal element. 9A shows a seal forming process for forming an ultraviolet curable seal on a transparent substrate, and FIG. 9B shows a liquid crystal dropping process for dropping liquid crystal on the inner area of the seal. 10 (c) shows a process of stacking two transparent substrates, and FIG. 10 (d) shows a process of curing the seal.

  First, in the seal forming step shown in FIG. 9A, a frame-shaped seal 3 made of an ultraviolet curable resin is formed in a closed ring shape on the surface of the transparent substrate 2b by using screen printing or a dispenser coating method.

  Next, in the liquid crystal dropping step shown in FIG. 9B, the liquid crystal 4 is dropped on the inner region of the frame-shaped seal 3.

  Next, in the overlapping step shown in FIG. 10C, the transparent substrate 2a is overlapped with the transparent substrate 2b via the frame-shaped seal 3. At this time, the frame-shaped seal 3 is crushed to a predetermined gap thickness, and the frame-shaped seal 3 spreads inwardly and outwardly from the seal formation location according to the amount of the frame-shaped seal 3 disposed on the transparent substrate 2b. Therefore, the frame-shaped seal 3 has a width wider than the seal width in the seal forming process shown in FIG.

  Finally, in the seal curing step shown in FIG. 10 (d), far ultraviolet or near ultraviolet seal curing light 9 is irradiated through the transparent substrate 2a or the transparent substrate 2b to cure the frame-shaped seal 3. Thus, the conventional liquid crystal element 20 is completed.

Japanese Patent No. 3443226 (page 3, FIG. 1) JP-A-11-109388 (page 3, FIG. 1-3)

  However, when the conventional liquid crystal element 20 shown in FIGS. 8A and 8B is a liquid crystal element with a reduced outer size applied to an optical pickup device, the distance between the effective diameter 6 and the frame-shaped seal 3. The problem arises that 7b becomes very narrow and it is difficult to manufacture this cell. The reason will be described.

  When manufacturing a small liquid crystal element 20 having a small outer size, the inner diameter of the frame-shaped seal 3 varies depending on the amount of application of the frame-shaped seal 3 in the seal forming step shown in FIG. Here, if the application amount of the frame-shaped seal 3 is too small, the transparent substrates 2a and 2b cannot be bonded with sufficient strength. On the other hand, if the application amount of the frame-shaped seal 3 is too large, the frame-shaped seal 3 will enter the inside of the effective diameter 6 in the steps shown in FIGS. 10 (c) and 10 (d). . The application amount of the frame-shaped seal 3 is very difficult to constantly supply in this step, and the spread of the completed frame-shaped seal 3 differs depending on the manufactured liquid crystal element. It will change. Thus, it is apparent that it is very difficult to produce the conventional liquid crystal element 20 that meets the purpose by the conventional manufacturing method.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to provide a liquid crystal element that can suppress the intrusion into the inner region of the seal as much as possible when two transparent substrates are overlapped, and a manufacturing method thereof.

In order to solve the above problems, the liquid crystal element of the present invention employs the following configuration.
The liquid crystal element of the present invention is a liquid crystal element in which two transparent substrates are overlapped via a frame-shaped seal and liquid crystal is arranged in an inner region of the frame-shaped seal. A groove is formed along the seal shape at the inner position where the seal is formed, and the frame-shaped seal covers the area extending from the position where the seal flows into the groove, or the groove, and the inner side of the groove. It arrange | positions in the area | region extended to both the outer sides, It is characterized by the above-mentioned.

  In addition, the liquid crystal element of the present invention is characterized in that the groove is formed on both of the two transparent substrates.

  The groove may be formed at a position where the two transparent substrates face each other.

  The manufacturing method of the liquid crystal element of the present invention is such that one and the other transparent substrates are overlapped with each other through a frame-shaped seal, and the liquid crystal element is disposed on the inner region of the frame-shaped seal. In addition, a groove forming step for forming a groove, a seal forming step for forming a frame-shaped seal in an outer region of the groove formed on the one transparent substrate, and the other transparent substrate on one side via the frame-shaped seal And a substrate overlaying step of curing the frame-shaped seal after the frame-shaped seal is allowed to flow into the groove.

The groove forming step is characterized in that grooves are formed on both the one transparent substrate and the other transparent substrate.

  As in the present invention, even if the outer size is reduced to the extent that a gap between the seal and the effective diameter cannot be secured sufficiently by providing a groove inside the seal and outside the effective diameter, the transparent substrate When the two are stacked, entry into the effective diameter of the seal can be suppressed as much as possible.

  Hereinafter, the liquid crystal element of the present invention will be described in detail with reference to the drawings.

  First, a configuration example of Example 1 of the liquid crystal element 1 of the present invention will be described with reference to FIG. 1A and 1B are a cross-sectional view and a plan view showing the configuration of the liquid crystal element 1 of the present invention. FIG. 1A shows a cross section taken along the line AA in FIG.

  As shown in FIGS. 1A and 1B, the liquid crystal element 1 of the present invention has a configuration in which the liquid crystal 4 is sandwiched between two transparent substrates 2a and 2b via a ring-shaped frame-shaped seal 3. ing. In addition, the transparent substrate 2 b is located outside the effective diameter 6 of the laser light oscillated from the laser light source in the optical pickup device, and the inner side wall of the frame-shaped seal 3 is positioned to enter the annular groove 5. Similarly, a frame-shaped seal 3 is formed. Here, the frame-shaped seal 3 in this figure is formed in a region extending from the position where it flows into the groove 5 to the outside. The liquid crystal element 1 configured as described above can have a configuration in which the effective diameter 6 and the space 7a between the frame-shaped seal 3 are sufficiently secured even if the outer size of the element is reduced. The reason will be described in detail later.

  Next, the manufacturing method of the liquid crystal element 1 of the present invention will be described with reference to FIGS. 2A and 2B are diagrams showing a method for manufacturing the liquid crystal element 1 of the present invention, FIG. 2A is a diagram showing a resist patterning process, FIG. 2B is a diagram showing an etching process, and FIG. (C) is a figure which shows a seal | sticker formation process. FIG. 3D is a diagram showing a liquid crystal dropping step, FIG. 3E is a diagram showing an overlaying step, and FIG. 3F is a diagram showing a seal curing step.

  First, in the resist patterning step shown in FIG. 2A, a resist is applied to the substrate surface of the transparent substrate 2b by spin coating, and then a resist 8 having a ring-shaped slit is formed by photolithography.

  Next, in the etching step shown in FIG. 2B, the transparent substrate 2b is wet-etched with an etching solution of hydrofluoric acid and hydrogen peroxide to form grooves 5 on the outer peripheral portion of the transparent substrate 2b. Thereafter, the resist 8 formed in the resist patterning step is peeled off.

  Next, by the seal forming step shown in FIG. 2C, a ring-shaped, ultraviolet curable frame-shaped seal 3 is formed on the surface of the transparent substrate 2b by the dispenser coating method or the screen printing method, Form in the outer area. At this time, the frame-shaped seal 3 is formed in the uncured state along the groove 5.

  Next, in the liquid crystal dropping step shown in FIG. 3D, the liquid crystal 4 is dropped from the upper part of the transparent substrate 2b into the inner region of the ring-shaped frame-shaped seal 3 by the dispenser coating method.

Next, the transparent substrate 2b and the transparent substrate 2a in which the liquid crystal 4 is dropped on the inner region of the frame-shaped seal 3 by the overlapping process shown in FIG. Overlapping in a vacuum state. Thereafter, the pressure is returned to atmospheric pressure, and the transparent substrates 2a and 2b are compressed to form a predetermined inter-substrate gap. Here, the frame-shaped seal 3 is crushed by the transparent substrate 2a and the transparent substrate 2b, and the frame-shaped seal 3 spreads to the outer region where the frame-shaped seal 3 is formed, but the inner side where the frame-shaped seal 3 is formed. Since the groove 5 is formed in the region, the frame-shaped seal 3 flows into the groove. Therefore, compared to the outward spread of the frame-shaped seal 3, the spread to the inner region can be suppressed as much as possible.

Next, in the seal curing step shown in FIG. 3 (f), far ultraviolet or about ² to 3 [J / cm ² ] from the outer surface of the transparent substrate 1a while pressing the superimposed transparent substrates 2a and 2b. By irradiating the seal curing light 9 in the near-ultraviolet wavelength band, the oligomer component of the resin material of the frame-shaped seal 3 is cross-linked and cured, and the transparent substrates 2a and 2b are firmly bonded and fixed, and the target liquid crystal element 1 is completed.

  In the above description, the grooves 5 are provided in the transparent substrate 2b, but may be provided in the transparent substrate 2a. Moreover, although the formation location of the frame-shaped seal | sticker 3 was made into the outer area | region of the groove | channel 5, since the spreading to the inner area | region of the frame-shaped seal | sticker 3 should just be suppressed by the said superimposition process, as shown in FIG. In the seal forming step, the frame-shaped seal 3 may be formed at a position where the frame-shaped seal 3 is engaged with the groove 5.

  Further, in the above description, the liquid crystal element 1 finally obtained in FIG. 3F is moved from the position where the liquid crystal element 1 flows into the groove 5 (the position where the outer side from the inner edge of the groove 5 is filled with the frame-shaped seal 3) to the outer side. In the example shown in FIG. 5A, the frame-shaped seal 3 does not fill the entire groove 5 and the finally formed liquid crystal element is partially grooved as shown in FIG. It is good also as a form with which the frame-shaped seal | sticker 3 fills 5 parts.

  Further, as shown in FIG. 5 (b), the frame-shaped seal 3 fills the entire groove 5, and the frame-shaped seal 3 further extends to the inside thereof, and is formed in a region extending both inside and outside the groove. It is good also as a form.

  Further, as shown in FIG. 5C, if the frame-shaped seal 3 is inserted into the groove 5, the frame-shaped seal 3 is displaced with respect to the groove 5 (from the center of the effective diameter 6 to the inside of the frame-shaped seal 3. May be formed in different forms).

  By adopting any one of the configurations described above, the frame-shaped seal 3 formed in the seal-forming process is caused to flow into the groove 5 in the inner region in the overlapping process, so that the frame-shaped seal 3 spreads outside. Compared to, the inward spread can be suppressed as much as possible. Therefore, by reducing the outer size of the liquid crystal element 1, the frame-shaped seal into the effective diameter 6 can be obtained even when the space 7 a (see FIG. 1) between the frame-shaped seal 3 and the effective diameter 6 cannot be secured sufficiently. Thus, the liquid crystal element 1 in which the penetration of 3 is suppressed as much as possible can be obtained.

  Next, another configuration example of the liquid crystal element of the present invention will be described with reference to FIG. FIG. 6 is a drawing showing the configuration of the liquid crystal element of this example.

  As shown in FIG. 6, in the liquid crystal element 1 of Example 2, the groove | channel distribute | arranged only to one transparent substrate of the liquid crystal element shown in Example 1 is provided in both the transparent substrate 2a and the transparent substrate 2b. In the following description, the same elements of the liquid crystal element shown in the first embodiment are given the same reference numerals, and redundant descriptions are omitted.

  As shown in FIG. 6A, in the liquid crystal element 1 shown in this embodiment, grooves 15a and 15b are arranged at positions where the transparent substrates 2a and 2b face each other.

  Thus, in this embodiment, since the grooves 15a and 15b are provided in both the transparent substrates 2a and 2b, the volume of the groove into which the frame-shaped seal 3 can flow is doubled, and the frame-shaped seal 3 The spread to the inner area can be suppressed.

  It should be noted that the positional relationship between the grooves 15a and 15b does not have to be opposed to each other as shown in FIG. 6 (a), and as shown in FIG. 6 (b), if it is outside the effective diameter 6, The grooves 15a and 15b may be arranged at positions that do not face each other. 6A and 6B can also be manufactured by the same method as shown in the first embodiment.

  Next, still another configuration example of the liquid crystal element of the present invention will be described with reference to FIG. FIG. 7 is a drawing showing the configuration of the liquid crystal element of this example.

  As shown in FIG. 7, in the liquid crystal element 1 of Example 3, the shape of the frame-shaped seal 3 is not the closed shape shown in Examples 1 and 2, but a shape having a sealing port 10. Except for the point that the hole 10 is blocked by the sealing agent 11 and the grooves 15a and 15b formed in the transparent substrates 2a and 2b are not in a closed ring shape, the configuration is the same as that of the second embodiment.

  Further, in the liquid crystal element 1 in this embodiment, a frame-shaped seal 3 having a sealing opening 10 is applied to a transparent substrate 2a, and the transparent substrate 2a and another transparent substrate 2b are overlapped with each other and sealed in a vacuum apparatus. By injecting liquid crystal from the port 10 and closing the sealing port 10 with the sealing agent 11, the target liquid crystal element 1 can be obtained.

  Thus, even when the frame-shaped seal 3 is not in a closed ring shape as in the third embodiment, the frame-shaped seal 3 is applied to the transparent substrate 2a and then overlapped with another transparent substrate 2b. The seal 3 flows into the grooves 15a and 15b, and the spread of the frame-shaped seal 3 to the inner region inside the effective diameter 6 can be suppressed.

  And like Example 2, the liquid crystal element 1 which suppressed that the frame-shaped seal | sticker 3 spreads in the effective diameter 6 when a board | substrate is piled up can be provided.

It is the top view and sectional drawing which show the structural example of the liquid crystal element of this invention. It is process drawing which showed the manufacturing method of the liquid crystal element of this invention. FIG. 3 is a process diagram illustrating a manufacturing method continued from FIG. 2. It is the top view and sectional drawing which show the modification of the seal | sticker application | coating of this invention. It is the top view and sectional drawing which show the modification of the liquid crystal element of this invention. It is the top view and sectional drawing which show the structural example of the liquid crystal element concerning Example 2 of this invention. It is the top view and sectional drawing which show the structural example of the liquid crystal element concerning Example 3 of this invention. It is the top view and sectional drawing which show the outline of the conventional liquid crystal element. It is process drawing which shows the manufacturing method of the conventional liquid crystal element. FIG. 10 is a process diagram illustrating the manufacturing method continued from FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal element 2a, 2b Transparent substrate 3 Frame-shaped seal 4 Liquid crystal 5, 5a, 5b, 15a, 15b Groove 6 Effective diameter 7a, 7b Space | interval 8 Resist 9 Seal hardening light 10 Sealing port 11 Sealing agent

Claims (5)

In a liquid crystal element in which two transparent substrates are overlapped via a frame-shaped seal and liquid crystal is arranged in the inner region of the frame-shaped seal,
On at least one of the two transparent substrates, a groove is formed along the seal shape at an inner position where the frame-shaped seal is formed,
The frame-shaped seal is disposed in a region extending from the position where it flows into the groove to the outside, or in a region covering the groove and extending both inside and outside the groove. Liquid crystal element. The liquid crystal element according to claim 1, wherein the groove is formed in both of the two transparent substrates. The liquid crystal element according to claim 2, wherein the groove is formed at a position where the two transparent substrates face each other. In a method for manufacturing a liquid crystal element in which one and the other transparent substrates are overlapped via a frame-shaped seal, and a liquid crystal is arranged in an inner region of the frame-shaped seal,
A groove forming step of forming a groove on the surface of the one transparent substrate;
A seal forming step of forming the frame-shaped seal in an outer region of the groove formed in the one transparent substrate;
A substrate overlaying step of superimposing the other transparent substrate on the one transparent substrate via the frame-shaped seal, allowing the frame-shaped seal to flow into the groove, and then curing the frame-shaped seal; A method for producing a liquid crystal element, comprising: The method for manufacturing a liquid crystal element according to claim 4, wherein the groove forming step is a step of forming the groove on both the one transparent substrate and the other transparent substrate.

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