WO2005098479A1

WO2005098479A1 - Double liquid-crystal aberration correcting element and its manufacturing method

Info

Publication number: WO2005098479A1
Application number: PCT/JP2005/005500
Authority: WO
Inventors: Nobuyoshi Nakagawa; Naoko Yoshida
Original assignee: Binit Corporation
Priority date: 2004-03-31
Filing date: 2005-03-25
Publication date: 2005-10-20
Also published as: KR100803340B1; JPWO2005098479A1; KR20060132935A; CN100409032C; JP4532482B2; CN1938606A

Abstract

A novel double liquid-crystal aberration correcting element smaller and lighter than conventional ones. The double liquid-crystal aberration correcting element (1) is composed of two liquid-crystal aberration correcting elements stacked in the direction of the thickness. Each liquid-crystal aberration correcting element comprises a pair of substrates on one of which a common electrode is provided and on the other of which a segment electrode (21) having a non electrode portion is provided and a liquid crystal interposed between the paired substrates. Holes (30A, 30B, 30C) are made in the thickness direction in each of the substrates, and terminals (31A, 31B, 31C) each connected to one of the common and segment electrodes are provided to the holes respectively. An injection hole (60) through which the liquid crystal is injected is made in one of the substrates. The alignment directions of the liquid crystal of the two liquid-crystal aberration correcting elements during voltage nonapplication are perpendicular to each other.

Description

Double liquid crystal aberration correcting element and method of manufacturing the same

Technical field

[0001] The present invention relates to a liquid crystal aberration correction element used in an optical disc device for correcting a difference that occurs during recording / reproducing with an optical pickup. In particular, a blue-violet semiconductor laser is used as a light source, and is suitably used for a large-capacity next-generation optical disc (Blu-ray disc; BD) having a plurality of recording layers. The present invention belongs to the technical field of double liquid crystal aberration correction element and its manufacturing method.

Background art

Conventionally, various optical disks such as CDs and DVDs are known as information recording media. These optical discs cause aberrations (distortion of the condensed spot) due to thickness shift or warpage due to rotation, so it is required to correct the aberrations and increase the recording / reproducing accuracy.

[0003] As a technique for correcting the aberration, a method of driving a collimator lens by an actuator and a method of using a liquid crystal aberration correction element are known.

The former method has a problem that an optical pickup is complicated because an actuator is required, and it is not possible to cope with high-precision correction.

On the other hand, the liquid crystal aberration correcting element forms the electrodes of the liquid crystal panel in, for example, a concentric ring shape, thereby performing different phase control between the central portion and the outer edge portion of the light beam. Since the liquid crystal aberration correcting element is arranged on the same optical axis together with the objective lens in the optical pickup, it has been desired to reduce the size and weight so that good driving can be obtained.

[0004] In recent years, large-capacity optical discs such as Blu-ray discs (BD) have been developed due to the shortening of the light source wavelength and the high NA of the objective lens. Since this BD will have a plurality of recording layers in the thickness direction in the future, it is necessary to adjust the focal position of the laser to different depths, and since the light source wavelength is short, variations in cover layer thickness and disc The wavefront aberration that occurs when the allowable amount for the inclination is small tends to increase. In order to address this problem, a double liquid crystal aberration correction element has been proposed in which the above-described two elements are combined and the detection accuracy is improved by performing aberration correction on the forward path and the return path. [0005] As a conventional double liquid crystal aberration correction element, for example, (Patent Document 1) discloses a forward path in which emitted light is directed from a light source to a magneto-optical recording medium and a directed path to a magneto-optical recording medium. Two phase correction elements are provided in the optical path shared by the return path, and each phase correction element includes a pair of transparent substrates with transparent electrodes, and a liquid crystal layer is narrow between the pair of transparent substrates. The transparent electrode formed on at least one of the two phase correction elements when a voltage is applied is a split electrode that is split so that the wavefront aberration of the emitted light can be corrected. An example is described in which the orientation directions of the liquid crystal molecules of the liquid crystal layers constituting the two phase correction elements are orthogonal to each other when a voltage having the same retardation value as that of the two phase correction elements is not applied.

In the above conventional device, as shown in FIG. 2 of (Patent Document 1), a substrate on one side of the device is made longer to form an electrode lead portion in that portion, and the electrode lead portion and the control circuit are connected to each other. Are connected by a flexible printed circuit board or the like.

In this case, since a force is applied to the portion where the electrode is drawn out on the glass substrate, if the glass substrate is made thinner, there is a risk of cracking and chipping.Thus, the thickness is limited in terms of strength (0.3 -0.5 mm). Therefore, when the two elements were combined, the overall thickness was increased, and sufficient light weight could not be achieved. In addition, since the substrate on one side is formed longer, the element becomes larger by that amount, and furthermore, the weight balance of the element itself is lost, so that there is a problem that high-precision driving becomes difficult.

[0007] In addition, the liquid crystal aberration correction element is required to achieve a storage temperature range of 40 to 90 ° C and a use temperature range of -20 to 80 ° C, particularly when considering applications such as in-vehicle use. When the temperature changes, the liquid crystal and the substrate expand and contract, and at this time, the expansion rates of the liquid crystal and the substrate are different. Therefore, as described above (Patent Document 1), the substrate is formed long on one side and the terminals are concentrated there. In this case, the entire structure is deformed non-uniformly, and as a result, the obtained correction effect may be adversely affected.

Further, when manufacturing a conventional device, two substrates having different sizes are opposed to each other, and a liquid crystal is injected and sealed through a gap on a side surface of the substrate. For this reason, it is necessary to manufacture each combination of substrates one by one and process the liquid crystal in each case, and to inject and seal the liquid crystal in each case, resulting in poor production efficiency and high cost. was there. Also, side Therefore, two types of devices having different alignment directions of the liquid crystal molecules with respect to the position of the electrode lead-out portion provided in the above had to be manufactured separately, which was inefficient.

In addition, as described above, since the electrode lead-out portion is provided to protrude to the side of the element, it is necessary to perform a product inspection for each element that has been finally processed, which is inefficient. there were.

[0009] On the other hand, in order to perform good correction, it is ideal to add an opposite phase difference to the generated aberration. However, when the electrode area is concentrically divided as in, for example, (Patent Document 2), there is a problem that the obtained phase difference becomes step-like.

Therefore, there has been a demand for the development of a double liquid crystal aberration correction element capable of linearly correcting the generated aberration.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-319202 (Claim 1, Paragraph 0038, FIG. 2)

Patent Document 2: Japanese Patent Application Laid-Open No. 2002-237077 (Claim 1, Paragraph 0014)

Disclosure of the invention

Problems to be solved by the invention

[0011] Therefore, an object of the present invention is to provide a novel double liquid crystal aberration correction element that can be made smaller and lighter than conventional elements.

It is another object of the present invention to provide a dual liquid crystal aberration correction element capable of linearly correcting aberrations caused by a thickness deviation of an optical disc and thereby improving the recording / reproducing accuracy.

[0012] It is another object of the present invention to provide a double liquid crystal aberration correction element that can maintain the performance of the element without causing non-uniform deformation due to a temperature change.

[0013] It is still another object of the present invention to provide a method of manufacturing a double liquid crystal aberration correction element that is excellent in production efficiency, low in cost, and can perform element inspection efficiently.

Means for solving the problem

[0014] In order to solve the above problems, the present invention comprises two liquid crystal aberration correction elements stacked in the thickness direction, and each of the liquid crystal aberration correction elements has a common electrode on one side and a segment electrode on the other side. Comprising a pair of substrates formed and a liquid crystal sandwiched between the pair of substrates. In each of the pair of substrates, a plurality of holes are drilled in the thickness direction, and the holes are provided with terminals to be connected to the common electrode and the segment electrode. An injection port for injecting liquid crystal is formed on one side of the substrate, and a double liquid crystal aberration compensating element is provided in which the liquid crystal alignment direction when no voltage is applied is orthogonal to the two liquid crystal aberration compensating elements. .

According to the above configuration, the terminal for connecting to the common electrode and the segment electrode, and the liquid crystal injection port are arranged on the surface of the substrate through the hole.

[0016] In the present invention, two liquid crystal aberration correcting elements are also stacked in the thickness direction, and each of the liquid crystal aberration correcting elements has a pair of common electrodes formed on one side and segment electrodes formed on the other side. And a liquid crystal sandwiched between the pair of substrates. In the segment electrode, a plurality of non-electrode portions having no electrode material are sized or arranged according to positions on the segment electrode. The gap is formed by changing the distance or both, and the liquid crystal is non-uniformly aligned when a voltage is applied inside the non-electrode portion. A plurality of holes are formed in each of the pair of substrates in the thickness direction. At the same time, the holes are provided with terminals of the common electrode and the segment electrode to be connected to each other, and an injection port for injecting liquid crystal is formed on one of the pair of substrates. When no voltage is applied The present invention provides a double liquid crystal aberration corrector in which the orientation of the liquid crystal is orthogonal between two liquid crystal aberration correctors.

According to the above configuration, in addition to the above-described functions, an electric field is weakly formed in a central portion of the plurality of non-electrode portions in a direction perpendicular to the electrode, and an electric field is formed at an end portion of the non-electrode portion. Since the electric field is formed in a tilted direction, the liquid crystal molecules are non-uniformly aligned along the distribution of the electric field, thereby obtaining a lens effect in which the refractive index changes continuously around the central force of the non-electrode portion. Therefore, by allowing the light beam to pass through the lens portion, a predetermined phase difference is given and the aberration is corrected. In particular, by changing the size or the arrangement interval of the non-electrode portions, the phase difference obtained in each region is changed, and optimal correction according to aberration is performed as a whole element.

Further, according to the present invention, in the above-described double liquid crystal aberration correction element, the substrate is formed in a square shape, and the liquid crystal is sealed along a circular area of the substrate through which a light beam passes. A liquid crystal injection port and a terminal are provided near a corner portion other than the circular region.

According to the above configuration, the vicinity of the corner of the substrate is effectively used as a space for forming a hole, and the weight balance of the element is improved. Further, when the liquid crystal expands and contracts, the whole liquid crystal is uniformly deformed.

[0020] Further, the present invention provides the dual liquid crystal aberration correction element described above, wherein terminals connected to a common electrode of each of the stacked liquid crystal aberration correction elements are connected to a segment electrode of one of the liquid crystal aberration correction elements. The terminals connected to each other and the terminals connected to the segment electrodes of the other liquid crystal aberration correction element are connected to each other in the thickness direction, and are provided on one substrate located outside the double liquid crystal aberration correction element. It is characterized by being aggregated in each.

Further, according to the present invention, in the double liquid crystal aberration correcting element described above, terminals connected to a common electrode of each of the stacked liquid crystal aberration correcting elements are connected to a segment electrode of one of the liquid crystal aberration correcting elements. The terminals connected to each other and the terminals connected to the segment electrodes of the other liquid crystal aberration correction element are connected to each other in the thickness direction, and are provided on one substrate located outside the double liquid crystal aberration correction element. It is characterized by being aggregated in each.

According to the above configuration, the terminals for driving the elements are collectively arranged on one substrate.

[0023] Further, according to the present invention, in the above-described double liquid crystal aberration correction element, a terminal connected to a segment electrode of one liquid crystal aberration correction element and a segment electrode of the other liquid crystal aberration correction element. The terminal is provided near a corner located at a diagonal of the square substrate, and the terminal connected to the common electrode and the liquid crystal injection port are provided near the remaining corner.

According to the above configuration, the position of each terminal is set in consideration of efficiency in manufacturing the element.

[0025] Further, the present invention is the method for manufacturing a double liquid crystal aberration corrector described above, wherein a terminal and an injection port corresponding to a large number of liquid crystal aberration correctors are provided on a substrate serving as a base material. Forming a segment electrode, combining the terminal, injection port, and the substrate on which the segment electrode is formed with a terminal provided at a position facing the substrate and another substrate on which a common electrode is formed, A step of injecting liquid crystal from the injection port after the combination, and a set in which a large number of liquid crystal aberration correction elements manufactured through the above-described steps are arranged, turn over another set obtained through the same steps and turn over. This is a method for manufacturing a double liquid crystal aberration correction element, which comprises a step of stacking layers after rotating each other, and a step of dividing the element into individual double liquid crystal aberration correction elements.

[0026] Further, the present invention is the method for manufacturing a double liquid crystal aberration correction element described above, wherein a step of providing terminals corresponding to a large number of liquid crystal aberration correction elements on a substrate serving as a base material, Forming a common electrode on the substrate on which the terminal and the segment electrode are formed, and providing a terminal and an injection port at a position opposite to the substrate on which the terminal and the segment electrode are formed, and combining another substrate on which the common electrode is formed. A step of injecting liquid crystal from an inlet port, and turning over another set obtained through the same steps with respect to a set in which a large number of liquid crystal aberration correcting elements manufactured through the above steps are arranged. This is a method for manufacturing a double liquid crystal aberration correction element, which comprises a step of laminating after rotation by two degrees, and a step of dividing into individual double liquid crystal aberration correction elements.

[0027] According to the above means, the production of the double liquid crystal aberration correction element proceeds with the state of the base material substrate until the final step. Then, two liquid crystal aberration correction elements of the forward path and the return path in which the liquid crystal orientation directions are orthogonal to each other are manufactured by the same process.

According to the present invention, in the above-described manufacturing method, an inspection wiring commonly connected to each terminal is formed on the surface of the substrate, and a large number of liquid crystal aberration correction elements are arranged. The inspection using the wiring is performed before or after the step of laminating another set with respect to the set of rows, or before or during the step of cutting into individual double liquid crystal aberration correction elements. Features.

[0029] According to the above means, the operation of the elements is checked at once in the state of the base material before being divided into individual elements.

[0030] Further, according to any one of the above-described manufacturing methods, when another set is stacked on a set in which a large number of liquid crystal aberration correction elements are arranged, a light beam is passed in a vacuum. Do It is characterized by being laminated via a sealing material provided in a closed state so as to surround a circular region.

[0031] According to the above means, since the space between the two liquid crystal aberration correction elements is in a vacuum state and there is no adhesive, a high light transmittance is maintained.

Further, according to the present invention, in the manufacturing method according to any one of the above, when another set is stacked on a set in which a large number of liquid crystal aberration correcting elements are arranged, a light beam passes in the atmosphere. The sealing material is laminated via a sealing material provided in a partially opened state and an adhesive provided inside the sealing material so as to surround the circular region.

[0033] According to the above means, the process power for stacking the two liquid crystal aberration correction elements is efficiently performed in the atmosphere. In this case, it is preferable to select an adhesive having a refractive index close to that of the substrate.

The invention's effect

[0034] The dual liquid crystal aberration correction element of the present invention has a hole formed in the surface of the substrate and the hole is used as a terminal. Is not added. Therefore, a thinner substrate can be employed, and as a result, a lighter weight device can be achieved.

Further, by arranging the terminals on the surface of the substrate, the size of the device can be reduced by that much.

Further, when a plurality of non-electrode portions are formed on the segment electrode, the lens effect is reduced by aligning the liquid crystal molecules along a non-uniform electric field distribution formed at the positions of the non-electrode portions. Cause. As a result, aberrations generated due to a deviation in the thickness of the optical disk or the like can be corrected freely.

[0037] In addition, since the liquid crystal is sandwiched in a circle at the center of the square substrate and terminals and the like are provided at the corners of the substrate, the weight balance of the element is excellent, and even if the liquid crystal expands or contracts due to a temperature change, it is improper. Uniform deformation does not occur, and the performance of the element can be maintained.

Further, according to the method for manufacturing a double liquid crystal aberration correcting element of the present invention, the steps of forming the terminals and the step of injecting the liquid crystal are all performed in the state of the base material before being separated into individual elements. As a result, production efficiency is improved and costs can be significantly reduced. In addition, when each element is inspected, the inspection can be performed in the state of the base material, so that high efficiency can be achieved.

Furthermore, two liquid crystal aberration correction elements to be laminated can be manufactured in exactly the same process. By simply turning one of them upside down and rotating it by 90 degrees, a double element in which the liquid crystal orientation directions are orthogonal to each other can be easily manufactured. it can. Therefore, productivity is extremely high and stable quality can be obtained.

Brief Description of Drawings

FIG. 1 is a plan view showing one embodiment of a double liquid crystal aberration correction element according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1.

FIG. 3 is a sectional view taken along line BB of FIG. 1.

FIG. 4 is an enlarged view of a portion S in FIG. 1.

FIG. 5 is a view for explaining an alignment state of liquid crystal when voltage is applied!

FIG. 6 is a flowchart showing a manufacturing process of a double liquid crystal aberration correction element.

FIG. 7 is a flowchart showing a manufacturing process of a double liquid crystal aberration correction element.

FIG. 8 is a diagram showing a state of S103 in a P direction.

FIG. 9 is a sectional view of a terminal portion showing a state of S103.

FIG. 10 is a diagram showing a state of S106 in a P direction.

FIG. 11 is a diagram showing a state of S108 in a P direction.

FIG. 12 is a diagram showing a state of S205 in the Q direction.

FIG. 13 is a view showing the state of S104 in the R direction.

FIG. 14 is a diagram showing a state of S501.

FIG. 15 is a diagram showing a state of S305.

FIG. 16 is a diagram showing a state of S504.

FIG. 17 is a diagram showing another embodiment of the state of S305.

Explanation of symbols

[0040] 1 Double liquid crystal aberration correction element

1A, IB liquid crystal aberration correction element

10, 11 substrates 101 corner

20 Common electrode

21 segment electrode

211 Non-electrode site

30A-30F hole

31A- 31F terminal

40 LCD

50, 51, 51A Seal material

52 adhesive

60 Inlet

61 Sealant

70 Conductive material

80 mask

90 Wiring

100, 110 Base substrate

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described in detail.

FIG. 1 is a plan view of a double liquid crystal aberration correcting element according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a sectional view taken along line BB of FIG. As shown in FIG. 1 and FIG. 3, the double liquid crystal aberration correction element 1 is composed of two liquid crystal difference correction elements 1A and IB having the same constituent power in the thickness direction via a conductive material 70 and a sealing material 51. It is constructed by stacking. The liquid crystal aberration correcting element 1A (similarly to 1B) is schematically configured by sandwiching a liquid crystal 40 between a substrate 10 on which a common electrode 20 is formed and a substrate 11 on which a segment electrode 21 is formed. . A liquid crystal alignment film and a transparent insulating layer generally provided between the common electrode 20 and the liquid crystal 40 and between the segment electrode 21 and the liquid crystal 40, and an antireflection film provided on the substrates 10 and 11 And the like are not shown. Further, the liquid crystal 40 is sealed inside by a seal material 50.

This double liquid crystal aberration correction element 1 allows a light beam to pass through a region where the liquid crystal 40 is provided, At this time, by applying a voltage between the common electrode 20 and the segment electrode 21, an alignment state of the liquid crystal 40, which is different depending on the position in the region, that is, a phase difference is given, thereby correcting light aberration. . At this time, since the liquid crystal aberration correcting elements 1A and IB make the orientation directions of the liquid crystal 40 orthogonal to each other when no voltage is applied, it is possible to satisfactorily correct the aberration in the forward path and the return path.

Here, the configuration of the segment electrode 21 will be described in detail.

In this embodiment, as shown in FIG. 4, which is an enlarged view of a portion S in FIG. 1, a plurality of non-electrode portions 211 having no electrode material are formed in the segment electrode 21 in a hole shape. The size and arrangement interval of the plurality of non-electrode portions 211 are continuously changed according to the positions on the segment electrodes 21. It should be noted that the number of non-electrode portions 211 is small for convenience in FIG. 4. In fact, many non-electrode portions 211 are formed more finely. Then, in this embodiment, along the radial direction r of the segment electrode 21, the size dl of the non-electrode portion 211 is changed from a large diameter to a once small diameter and becomes a large diameter again. A continuous pattern is formed so that the width becomes wider and the distance becomes narrower and then becomes wider again.

When a voltage is applied between the common electrode 20 and the segment electrode 21, the state of the electric field E near the non-electrode portion 211 is as shown in FIG. That is, in the part a where the common electrode 20 and the segment electrode 21 face each other, a strong electric field is formed in the direction perpendicular to the electrode, and in the part b which is the center of the non-electrode part 211, the electric field perpendicular to the electrode is also formed. A weak electric field is formed in the direction. Then, at a portion c near the boundary between the non-electrode portion 211 and the segment electrode 21, the electric field is inclined toward the segment electrode 21.

Then, when the dielectric anisotropy of the liquid crystal 40 is positive, the liquid crystal molecules are oriented along the electric field E, so that the liquid crystal molecules are arranged perpendicularly to the electrode in the part a, and in the part b. Since the electric field is weak, the state remains parallel to the electrodes, and the portion c is obliquely oriented. That is, the liquid crystal 40 is in a non-uniform alignment state inside the non-electrode portion 211. At this time, since the refractive index for the light passing through the element (extraordinary light) forms a distribution that decreases continuously toward the center of the non-electrode portion 211, the effect of the convex lens on the non-electrode portion 211 is obtained. Will be shown. This can give a phase difference to the passing light it can.

Therefore, when the size and arrangement interval of the non-electrode portions 211 are continuously changed depending on the position on the segment electrode 21, the phase difference obtained at each position is different. By appropriately designing the arrangement pattern, aberration can be linearly corrected as a whole element.

When the applied voltage is changed, the alignment state of the liquid crystal molecules changes accordingly. For example, when the voltage is increased, the liquid crystal molecules are vertically aligned even at the center of the non-electrode portion 211, and conversely, the refractive index increases toward the center of the non-electrode portion 211 so as to exhibit a concave lens effect. Become. In other words, since the phase difference curve obtained for the entire device can be changed by the applied voltage, for example, the correction amount is calculated based on V based on the reproduction (RF) waveform, and the voltage is controlled according to the result. It is also possible to correct the aberrations that occur in real time.

Further, in the example of FIG. 4, the size and the arrangement interval of the non-electrode portions 211 are changed along the radial direction r. By doing so, a phase difference curve that changes concentrically according to the arrangement pattern of the non-electrode portions 211 is obtained, so that spherical aberration generated due to a disc thickness deviation can be favorably corrected. Also, since the size and arrangement interval of the non-electrode portions 211 are continuously changed, the biasing force is not a stepwise discontinuous correction like a conventional aberration correction element in which a segment electrode is divided concentrically. Linear correction is possible.

Further, it is preferable that the arrangement interval of the non-electrode portions 211 be within each area when the segment electrode 21 is concentrically divided (for example, the area M is irregular (random arrangement) in the area. The spacings hi and h2 are slightly different as shown in Fig. 4. This prevents light passing through adjacent non-electrode portions from interfering with each other and disturbing the wavefront. can do.

When it is expected that there is almost no interference effect due to the relationship between the wavelength of light and the arrangement interval, hi and h2 may be the same and arranged regularly.

As a method of forming the non-electrode portions 211, first, an electrode material is formed on the entire surface of the substrate 11, and then a plurality of non-electrode portions 211 are formed in a desired arrangement pattern by a photo process. Is preferably used. In this way, a fine arrangement pattern that changes continuously can be easily created. Alternatively, a method may be used in which the segment electrode 21 is deposited on the substrate 11 by vapor deposition, plating, or the like via a mask.

Next, as the substrates 10 and 11, a transparent substrate such as a glass substrate is used. Further, as the common electrode 20 and the segment electrode 21, a transparent electrode such as ITO on which an indium tin oxide film is formed is appropriately employed.

In this embodiment, holes 30A, 30B, and 30C are formed in the thickness direction of substrate 11, and holes 30D, 30E, and 30F are similarly formed in substrate 10. Each hole is provided with terminals 31A, 31B, 31C, 31D, 31E and 31F for connection to the common electrode 20 and the segment electrode 21, respectively. That is, the terminals 31A and 31D are connected to the segment electrode 21 of the liquid crystal aberration corrector 1A, the terminals 31B and 31E are connected to the common electrode 20, and the terminals 31C and 31F are connected to the segment electrode 21 of the liquid crystal aberration corrector 1B. The terminals facing each other (for example, the terminal 31B and the terminal 31E) are connected via a conductive material 70. Each terminal is formed by plating a metal such as Ni—Au along the inner peripheral surface of the hole.

By arranging the terminals on the surfaces of the substrates 10 and 11 as described above, a biased force is applied to the element as compared with a conventional element in which terminals are collectively arranged on the side of the substrate. Cracks that can easily be broken. Therefore, the substrates 10 and 11 are thinner, for example, 0.2 mm

) Can be performed, and the element can be lightened. More specifically, 40% or more of the conventional level (about 10% of the effect of changing from the conventional terminal to the terminal placed on the surface, and the effect of changing the board thickness from 0.3 mm to 0.2 mm About 33%).

In this embodiment, an injection port 60 for injecting the liquid crystal 40 between the substrates 10 and 11 is formed on the surface of the substrate 11. The shape of the inlet 60 is circular, elliptical, or the like, and is appropriately sealed with the sealing material 61 after the liquid crystal 40 is injected.

In particular, in the example of FIG. 1, all of the terminals 31A to 31F and the liquid crystal injection port 60 are arranged on the surfaces of the substrates 10 and 11, and the opposite terminals are connected to each other in the thickness direction. Since the driving terminals provided on the liquid crystal aberration correcting element 1A are integrated, the production efficiency of the element can be increased as described later.

Further, in the example of FIG. 1, the light beam passes through holes 30A-30F and liquid crystal injection port 60. Except for the circular area (the area where the segment electrode 21 and the common electrode 20 are formed), it is formed near the corner 101 on the rectangular substrate 11 (10). Further, the seal member 50 is provided in a substantially circular shape so that the liquid crystal 40 is sealed in a circular region through which the light beam passes. With this configuration, the surplus portion of the substrate 11 through which the light beam does not pass can be effectively used as the position of the terminal and the like, and the element can be further reduced in size. In addition, by arranging the terminals and the like in the corner portions 101, the weight balance of the element can be optimized. As a result, high-precision driving becomes possible, and when the liquid crystal expands and contracts due to a temperature change, pressure is applied evenly to the substrate 11, so that non-uniform deformation does not occur and the performance of the element is maintained. be able to.

[0055] It should be noted that in a conventional device using a general liquid crystal (such as a liquid crystal display device), it is required that the frame portion (excess portion of the substrate) be made as narrow as possible with the expansion of the display area. Have been. In addition, since the number of terminals tends to increase in accordance with the high division drive method, etc., the idea of effectively utilizing the corner portions of the substrate can be said to be unique to the present invention.

Note that the arrangement pattern of the plurality of non-electrode portions 211 is not limited to the above embodiment. That is, the size and / or arrangement interval of the non-electrode portions 211 can be appropriately set according to the position on the segment electrode 21 in accordance with the generated aberration and the like. Specifically, for example, contrary to FIG. 4, there is a case where the size of the non-electrode portion is continuously changed from a small diameter to a large diameter or to a small diameter with the central force of the segment electrode 21 also directed toward the periphery. No. Further, the present invention is not limited to the case where the size and the arrangement interval are concentrically changed on the segment electrode 21, but is formed so that, for example, when the segment electrode 21 is divided into left and right regions, different arrangement patterns are formed in each region. You may. In this case, coma caused by the warpage of the disk can be effectively corrected.

Further, in the above-described embodiment, the case where the shape of the plurality of non-electrode portions 211 is circular has been described. However, the present invention is not limited to this. For example, the type of generated aberration, the rubbing direction, and the like are taken into consideration. , Can be different shapes. Specifically, an elliptical shape, a semicircular shape, and the like are given.

In the example of FIG. 1, the pattern of the segment electrode 21 is directly connected to the terminal 31 A. Alternatively, for example, after forming each electrode pattern that also produces a closed circular area force, each electrode and each terminal may be connected by a lead wire or the like.

In the above embodiment, the terminals provided on the substrates 10 and 11 are connected to each other in the thickness direction, and are integrated into the terminals on the uppermost substrate. The case where a plurality of non-electrode portions 211 are formed has been described as an example. However, the present invention is not limited to this case. For example, the present invention can be similarly applied to a case where a segment electrode is concentrically divided into a plurality of regions. Also in this case, the size and weight of the device can be reduced by arranging the terminals on the substrate. Alternatively, the segment electrode may be divided into left and right. In this case, coma generated by warpage of the optical disk can be corrected well.

The double liquid crystal aberration correction element 1 as described above constitutes an optical pickup together with, for example, a laser light source, a polarizer, a 1Z2 wavelength plate, a 1Z4 wavelength plate, an objective lens, a light receiving element, and the like, and is incorporated in an optical disk device. Can be used with

In particular, since the aberration in the forward path and the return path can be corrected, it can be suitably used for a high-density optical disc such as a next-generation BD (Blu-ray Disc) or a multilayer disc.

Next, a method of manufacturing the double liquid crystal aberration correcting element 1 according to the example of FIG. 1 described above will be described with reference to FIGS.

First, the processing steps of the substrate 11 in the liquid crystal correction element 1A will be described in order. FIG. 8 and FIG. 11 show a state in which the force in the P direction in FIG. 2 is viewed. First, as shown in FIGS. 6 and 8, holes 30A, 30B and 30C corresponding to a large number of liquid crystal aberration correcting elements and a liquid crystal injection port 60 are placed at predetermined positions on a substrate 110 serving as a base material. (S101). Subsequently, after an antireflection film (AR film) is formed on the entire surface of the substrate 110 serving as a base material (S102), terminals 31A, 31B, and 31C are provided in the respective holes (S103). As will be described later, the terminals 31A to 31C need to overlap each other when the substrate 110 is turned upside down and rotated by 90 degrees. Therefore, the substrate 110 as a base material is preferably square, and The same number of liquid crystal aberration correction elements are formed vertically and horizontally. When providing each terminal (for example, terminal 31A), as shown in FIG. 9, after forming a mask 80 on a portion other than the hole 30A, forming a metal to be the terminal 31A by plating or the like, This is preferably performed by removing the mask 80.

Subsequently, wiring used for an inspection described later is formed on the side viewed from the R direction in FIG. After that (S104), an electrode material is formed at a predetermined position by vapor deposition or the like (S105), and pattern jung is performed by etching or the like to produce a segment electrode 21 (S106). This state is shown in FIG. Note that the step of providing the terminal and the step of forming a wiring used for inspection may be performed before or after.

Next, a transparent insulating layer is laminated on the side in the P direction as necessary, a liquid crystal alignment film such as PVA is formed, and rubbing is performed (S 107). Further, a sealing material 50 for enclosing the liquid crystal is provided outside the segment electrode 21 by printing or the like (S108). This state is shown in FIG.

On the other hand, with respect to another substrate (substrate 10 side) to be opposed, as shown in FIG. 12 viewed from the Q direction in FIG. After forming holes 30D, 31E, 30F in the device (S201), forming an AR film (S202), providing terminals 31D, 31E, 31F (S203), depositing electrode materials, etc. (S204) Is performed to form the common electrode 20 (S205). In addition, a liquid crystal alignment film is formed and rubbing is performed (S206), and a conductive material for connecting to each terminal of the substrate 110 to be opposed is provided by printing or the like (S207). In some cases, the injection port 60 can be formed on the substrate 10 side, or the sealing material 50 can be printed on the substrate 10 side and the conductive material can be printed on the substrate 11 side.

Then, the substrate 110 and the substrate 100 on which the terminals and the like as described above are formed are combined to face each other (S301). This step is performed by bonding with an adhesive through a spacer.

Subsequently, the liquid crystal is injected into the inside of the sealing material 50 from the injection port 60 (S302), and sealed by a sealing material. Then, an operation test of the element is performed using the terminals arranged on the substrate 110 serving as a base material (S303). At this time, since the wiring 90 is previously formed on the substrate 110 as shown in FIG. 13 (S104), a 100% inspection is performed at once using the wiring 90. NG marking is performed on the parts that failed the inspection (S304).

Through the above steps (S101-S303), a set in which a large number of liquid crystal aberration correction elements 1A are arranged is obtained. Then, another set (in which the liquid crystal aberration correction elements 1B are arranged) manufactured through the same steps (S101 to S303) is laminated on this set (S501). At this time, as shown in FIG. 14, another set is turned upside down in the Z direction and rotated by 90 degrees in the X direction, and the substrate 100 side of the set in which the liquid crystal aberration correction elements 1A are arranged is connected to the liquid crystal aberration correction device. Element 1 By laminating the substrate 100 side of the set in which B is arranged, the common terminals and the corresponding segment terminals are combined, and a state in which the orientation directions of the liquid crystals are orthogonal is obtained.

When stacking the sets, the seal material 51 and the conductive material 70 are printed in advance between the sets (S305, S401). The sealing material 51 and the conductive material 70 may be provided on the liquid crystal aberration correction element 1A side, respectively, or may be provided on the opposite liquid crystal aberration correction element 1B side.

[0069] As shown in Fig. 15, the sealing material 51 can be provided in a closed state so as to surround a circular area through which a light beam passes. In this case, the work of laminating the sets needs to be performed in a vacuum so that the lamination state is not impaired by the expansion of the gas confined inside the sealing material 51. It is preferable that the sealing material 51 is in a closed state and the inside is vacuum, because dust and the like do not enter the inside and the light transmittance can be increased.

After the sets are stacked, the operation of the double liquid crystal aberration correction element is inspected using the terminals arranged on the substrate 110 serving as the base material (S502). Also at this time, as in the case described above, the 100% inspection can be performed at once using the wiring 90 formed on the substrate 110. NG marking is performed on the part that failed as a result of the inspection (S503).

Finally, as shown in FIG. 16, the substrate serving as a base material is cut into individual double liquid crystal aberration correction elements 1 using a dicer or the like (S 504), and the inspection process of a single product (S 505) is performed. After that, it is shipped (S507). In addition, the element which failed in the inspection of the single item is transferred to a discarding or repairing force or a regeneration process (S506).

When laminating the sets, instead of the sealing material 51 shown in FIG. 15, a seal provided in a partially open state so as to surround a circular region through which a light beam passes as shown in FIG. Material 51A may be interposed. In this case, an adhesive 52 is provided inside the sealing material 51A, and the sets are adhered to each other by the adhesive 52. In the example of FIG. 17, since the work of stacking the sets can be performed in the atmosphere, there is an advantage that the production efficiency is high.

According to the above-described manufacturing method, the formation of each terminal and electrode, the step of injecting liquid crystal, and the like are all performed in the state of the base material before being separated into individual elements, so that the production efficiency is extremely high. High costs can also be significantly reduced. Easily accommodates production scale expansion Noh.

In particular, the two liquid crystal aberration correcting elements to be laminated are manufactured in the same process rather than separately, and only one of them needs to be turned upside down and rotated 90 degrees, greatly improving the overall production efficiency.

Furthermore, the inspection process performed after injecting and sealing the liquid crystal can be performed simultaneously in the state of the base material, which is extremely useful in industry.

Claims

The scope of the claims

[1] Consisting of two liquid crystal aberration correction elements stacked in the thickness direction, each of the liquid crystal aberration correction elements has a pair of substrates each having a common electrode force on one side and a segment electrode formed on the other side, and the pair of substrates And a plurality of holes formed in each of the pair of substrates in a thickness direction, and a terminal connected to one of the common electrode and the segment electrode is formed in the hole. An injection hole for injecting liquid crystal is formed in one of the pair of substrates, and a double liquid crystal in which the orientation direction of the liquid crystal when no voltage is applied is orthogonal to the two liquid crystal difference correction elements. Aberration correction element.

[2] Two liquid crystal aberration correction elements stacked in the thickness direction, each of the liquid crystal aberration correction elements having a common electrode force on one side, a pair of substrates having a segment electrode formed on the other side, and the pair of substrates A plurality of non-electrode portions in which no electrode material is present are formed on the segment electrode by changing the size and / or the spacing between them depending on the position on the segment electrode; The liquid crystal is non-uniformly aligned when a voltage is applied inside the electrode portion, and a plurality of holes are formed in the thickness direction in each of the pair of substrates, and the common electrode and the segment are formed in the holes. A terminal connected to one of the electrodes is provided, an injection port for injecting liquid crystal is formed in one of the pair of substrates, and the alignment direction of the liquid crystal when no voltage is applied is two. Double crystal aberration correcting element formed by orthogonal AkiraOsamu difference correction element.

3. The double liquid crystal aberration correction device according to claim 2, wherein the substrate is formed in a quadrangular shape, and the liquid crystal is sealed along a circular region of the substrate through which a light beam passes, and near a corner other than the circular region. A dual liquid crystal aberration correction element, further comprising a liquid crystal injection port and a terminal.

[4] In the double liquid crystal aberration correcting element according to claim 2, terminals connected to a common electrode of each of the stacked liquid crystal aberration correcting elements, and terminals connected to a segment electrode of one of the liquid crystal aberration correcting elements. And the terminals connected to the segment electrodes of the other liquid crystal aberration correction element are connected to each other in the thickness direction, and are combined into terminals provided on one substrate located outside the double liquid crystal aberration correction element. A dual liquid crystal aberration correction element.

[5] In the double liquid crystal aberration correction element according to claim 3, terminals connected to a common electrode of each of the stacked liquid crystal aberration correction elements, and terminals connected to a segment electrode of one of the liquid crystal aberration correction elements. The terminals connected to the segment electrodes of the other liquid crystal aberration correction element are connected to each other in the thickness direction, and are collected on the terminal provided on one outermost substrate of the dual liquid crystal aberration correction element. A dual liquid crystal aberration correction element, characterized in that:

[6] In the double liquid crystal aberration correction element according to claim 5, the terminal connected to the segment electrode of one liquid crystal aberration correction element and the terminal connected to the segment electrode of the other liquid crystal aberration correction element include: Double liquid crystal aberration correction characterized in that it is provided near a corner located at a diagonal of a square substrate, and a terminal connected to a common electrode and a liquid crystal injection port are provided near the remaining corner. element.

7. The method for producing a double liquid crystal aberration correction element according to claim 6, wherein a step of providing terminals and injection ports corresponding to a large number of liquid crystal aberration correction elements on a substrate serving as a base material, A step of forming a contact electrode, a step of providing a terminal at a position facing the substrate on which the terminal, the injection port, and the segment electrode are formed, and combining another substrate on which a common electrode is formed. For a set in which a plurality of liquid crystal aberration correcting elements manufactured through the steps of injecting the liquid crystal and the above-described steps are arranged, another set obtained through the same steps is turned upside down and rotated 90 degrees. A method for manufacturing a double liquid crystal aberration correction element, comprising the steps of: laminating the liquid crystal aberration correction element by means of a liquid crystal aberration correction element;

[8] The method for producing a double liquid crystal aberration correcting element according to claim 6, wherein a step of providing terminals corresponding to a large number of liquid crystal aberration correcting elements on a substrate serving as a base material; After the combination, a step of providing a terminal and an injection port at a position facing the substrate on which the terminal and the segment electrode are formed, and combining another substrate on which a common electrode is formed. A step of injecting liquid crystal and a set in which a large number of liquid crystal aberration correcting elements manufactured through the above-described steps are arranged, and another set obtained through the same steps is turned upside down and rotated by 90 degrees. A dual liquid crystal aberration corrector comprising the steps of: Construction method.

[9] The manufacturing method according to claim 7 or 8, wherein a wiring for inspection connected to each terminal is formed on the surface of the substrate, and a plurality of liquid crystal aberration correction elements are arranged. On the other hand, before the step of laminating another set or before the step of separating into individual double liquid crystal aberration correcting elements, the inspection is performed using the wiring at one or both of the times. Manufacturing method of double liquid crystal aberration correction element.

[10] In the manufacturing method according to claim 7 or 8, when another set is stacked on the set in which a large number of liquid crystal aberration correction elements are arranged, a circular region through which a light beam passes is placed in a vacuum. A method for manufacturing a double liquid crystal aberration correction element, comprising laminating via a sealing material provided in a closed state.

[11] In the manufacturing method according to claim 9, when another set is stacked on a set in which a large number of liquid crystal aberration correction elements are arranged, the set is closed in a vacuum so as to surround a circular region through which a light beam passes. A method for manufacturing a double liquid crystal aberration correction element, comprising laminating via a sealing material provided in an inclined state.

[12] In the manufacturing method according to claim 7 or 8, when another set is stacked on the set in which a large number of liquid crystal aberration correcting elements are arranged, a circular region through which a light beam passes in the atmosphere is surrounded. A method for manufacturing a double liquid crystal aberration correction element, comprising: laminating a sealing material provided in a partially opened state and an adhesive provided inside the sealing material.

[13] In the manufacturing method according to claim 9, when another set is stacked on the set in which a large number of liquid crystal aberration correction elements are arranged, one set is formed so as to surround a circular area through which a light beam passes in the atmosphere. A method for manufacturing a double liquid crystal aberration correction element, comprising: laminating via a sealing material provided in a partially opened state and an adhesive provided inside the sealing material.