JP2010250197A - Liquid crystal optical element and pick-up device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable liquid crystal optical element capable of being easily and reliably connected with an external circuit. <P>SOLUTION: A second electrode 309 formed in an extension part of a third substrate 303 is connected with a first electrode 307 formed in an extension part of a second substrate 302 by using electrical conductive paste 306 in a region being different from another region where an FPC connection 305 and the second substrate 302 are mutually connected. As a result, the FPC 305 is connected to the second substrate 302 on one surface only of the second substrate 302. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

    The present invention relates to a liquid crystal optical element including a plurality of stacked substrates and a liquid crystal layer between the substrates, and a pickup device including the same.

  Conventionally, a liquid crystal optical element having a plurality of liquid crystal layers is known. A conventional example of such a liquid crystal optical element will be described with reference to FIG. FIG. 1 is a copy of the drawings in Patent Documents 1, 2, and 3, and shows a cross section of a liquid crystal optical element. In addition, since it demonstrates using the term used in the said patent document, even if it is an equivalent member between each patent document, it may be called differently. Moreover, the member number and hatching are changed for convenience of explanation.

  For example, FIG. 8 of Patent Document 1 shows a multilayer liquid crystal panel (liquid crystal optical element) in which three transparent substrates are laminated. The multilayer liquid crystal panel will be described with reference to FIG. FIG. 1A is a cross-sectional view of a multilayer liquid crystal panel that is a copy of FIG.

  In this multilayer liquid crystal panel, a second transparent substrate 102 and a third transparent substrate 103 are laminated on a first transparent substrate 101. A liquid crystal layer (not shown) is sandwiched between the first transparent substrate 101 and the second transparent substrate 102, and the first transparent substrate 101 extends from the second transparent substrate 102. A plurality of terminal electrodes (not shown) connected to drive electrodes (not shown) for applying a voltage to the liquid crystal layer are formed in the extending portion. Similarly, a liquid crystal layer (not shown) is sandwiched between the second transparent substrate 102 and the third transparent substrate 103, and the extended portion of the second transparent substrate 102 extends from the third transparent substrate 103. Also, a plurality of terminal electrodes (not shown) are formed. The terminal electrode groups formed in the two extending portions are connected by one flexible wiring film 104, and the other end of the flexible wiring film 104 is connected to the circuit side substrate 105.

  The liquid crystal layer is not limited to two layers. For example, Patent Document 2 discloses a liquid crystal display device (liquid crystal optical element) including four substrates and three liquid crystal layers sandwiched between the substrates. Has been. This liquid crystal display device will be described with reference to FIG. FIG. 1B is a cross-sectional view of a liquid crystal display device that is a copy of FIG.

  FIG. 1B shows a cross section of a guest-host liquid crystal display device in which three layers of cyan, yellow, and magenta are stacked. The first substrate 112, the second substrate 114, the third substrate 116, and the fourth substrate 118 are arranged apart from each other, and the periphery between the substrates is sealed by seals 126, 124, and 122. Liquid crystal layers 117, 115, and 113 are sealed in the gaps, respectively. In each of the first substrate 112, the second substrate 114, and the third substrate 116, a gate wiring (not shown) is drawn to the end of the substrate. Each substrate end portion becomes longer in order in the lower substrate, thereby forming a step. A connection pad is provided at each end of the gate wiring. The connection portion 131 of the circuit board 110, the connection pad 133 at the end of the first substrate 112, the connection pad 135 at the end of the second substrate 114, and the connection pad 137 at the end of the third substrate 116 are the common flexible substrate 120. Are electrically connected by bending them along the steps. The flexible substrate 120 has a common wiring (wiring for connecting three gate wirings) corresponding to the gate wiring of each step portion.

In the multilayer liquid crystal optical elements disclosed in Patent Documents 1 and 2, the connection portion of the flexible substrate forms a step. On the other hand, there is a liquid crystal optical element in which a central substrate is extended to secure a connection portion with a flexible substrate. For example, FIG. 4 of Patent Document 3 shows a transmitted light amount variable element (liquid crystal optical element) in which a central substrate is extended and connected to a flexible substrate on both sides of the extended portion. The transmitted light amount variable element will be described with reference to FIG. FIG. 1C is a cross-sectional view of the transmitted light amount variable element which is a copy of FIG.

  The upper half of the transmitted light amount variable element is provided on a pair of transparent substrates 201a and 201b arranged in parallel and the substrate surface of the transparent substrate 201b, and is periodically arranged so that a transparent member having a multilayer structure forms a diffraction grating. An electric field is applied to the liquid crystal 204a and the liquid crystal 204a sandwiched between the multilayer lattice member 203a disposed on the substrate, the pair of transparent substrates 201a and 201b provided with the multilayer lattice member 203a, and the multilayer lattice member 203a. Transparent electrodes 202a and 202b, a seal 205a, and a wiring 206a for applying a voltage having a predetermined waveform between the transparent electrodes 202a and 202b.

  Similarly, the lower half of the transmitted light amount variable element includes a multilayer lattice member 203b, a liquid crystal 204b, transparent electrodes 202c and 202d, and a seal 205b between a pair of transparent substrates 201b and 201c arranged in parallel. A wiring 206b for applying a voltage having a predetermined waveform between the transparent electrodes 202c and 202d is included.

  Here, the longitudinal direction of the upper half multilayer lattice member 203a is orthogonal to the longitudinal direction of the lower half multilayer lattice member 203b. Similarly, the alignment direction of the liquid crystal layer 204a is orthogonal to the alignment direction of the liquid crystal layer 204b. In this way, the upper half adjusts the amount of transmitted light of one linearly polarized light, and the lower half adjusts the amount of transmitted light of the other linearly polarized light orthogonal to one. As a result, the transmitted light amount variable element can handle natural light.

  The multilayer liquid crystal panel and the liquid crystal display device of FIGS. 1A and 1B are connected to the circuit side substrate 105 and the circuit substrate 110 by the single flexible wiring film 104 and the flexible substrate 120. On the other hand, the transmitted light amount variable element in FIG. 1C is connected to an external circuit through two wirings 206a and 206b. In order to simplify the connection structure, these wirings 206a and 206b are desirably formed on a single flexible substrate (hereinafter referred to as FPC).

  Therefore, a method for realizing the connection shown in FIG. 1C with one FPC will be described with reference to FIG. FIG. 2 is a plan view of an FPC shown as a comparative example. The FPC 206 is divided into two forks on the left side, and wiring (not shown) is formed on one surface. When the FPC 206 is bent along the line AB in the drawing, the wiring 206a and the wiring 206b can be opposed to each other. In this state, the wirings 206a and 206b are connected to the electrodes formed on both surfaces of the extended portion of the substrate 201b in FIG.

JP-A-57-62029 (see FIG. 8) Japanese Patent Laid-Open No. 10-260423 (see FIG. 1) WO2006 / 082901 (see FIG. 4)

    As shown in Patent Documents 1 and 2, when the substrate extends stepwise, has an FPC connection region on each step surface, and attempts to connect the external circuit and the electrode of the liquid crystal optical element with one FPC, When the wiring formed on the FPC is disconnected at the sharp corner of the stepped portion, or when the FPC and the electrode are thermocompression bonded at a certain stepped portion, unnecessary heat conduction occurs and the connection on the other stepped portion The finished structure is deformed by heating.

As shown in Patent Document 3, when the FPC and the electrodes of the liquid crystal optical element are connected on both sides of the extended substrate, the FPC shape can be changed from a rectangle even though the FPC can be made into one sheet as in the comparative example. Compared to this, the shape becomes complicated, and the number of FPCs cut out from a large sheet is reduced.

    In the first place, these problems occur because a liquid crystal optical element having a multilayer liquid crystal structure has a plurality of connection regions with external circuits. In addition, since there are a plurality of connection regions, the connection process becomes cumbersome. Accordingly, an object of the present invention has been made in view of the above problems, and an object thereof is to provide a highly reliable liquid crystal optical element that can be easily and reliably connected to an external circuit.

    The present invention relates to a liquid crystal optical element in which a liquid crystal layer is sandwiched between each of three or more substrates to be stacked and the liquid crystal layer is driven by energization with an external circuit. One of the two is provided with an extending portion extending outward from the outer edge of the other substrate, and a wiring electrode is provided on a surface of the extending portion exposed to the outside, and at least two extending portions are provided. Each of the wiring electrodes is connected one-to-one by a conductive member.

    The conductive member may be a conductive paste. This facilitates the manufacturing process because the connection between the wiring electrodes is completed by the coating process.

    Further, it is preferable that a connection electrode connected to an external circuit is formed on only one substrate. As a result, the connection between the plurality of wiring electrodes and the external circuit can be integrated in one place, so that the connection process can be simplified.

  Furthermore, the present invention provides a pickup apparatus for condensing a laser beam emitted from a light source onto an optical recording medium and detecting the laser beam reflected by the optical recording medium. A liquid crystal optical element is provided.

    According to the present invention, a plurality of wiring electrodes and an external circuit can be connected at a single location by connecting wiring electrodes between substrates or between the front and back surfaces of a substrate in a region different from the region for external circuit connection. Therefore, a highly reliable liquid crystal optical element that can be easily and reliably connected to an external circuit can be realized.

It is sectional drawing of the liquid crystal optical element shown as a prior art example. It is a top view of FPC shown as a comparative example. 2 is a cross-sectional view and a plan view of the liquid crystal optical element of Embodiment 1. FIG. It is the CD sectional view taken on the line shown in FIG.3 (b). It is a top view which shows the electrode of the liquid crystal optical element of FIG. It is explanatory drawing of the electrode connection process of the liquid crystal optical element of FIG. FIG. 6 is a cross-sectional view and a plan view of a liquid crystal optical element of Embodiment 2. It is sectional drawing and the top view of the liquid crystal optical element of Embodiment 3. It is sectional drawing and the top view of the liquid crystal optical element of Embodiment 4. It is explanatory drawing of the pick-up apparatus of Embodiment 5.

Hereinafter, preferred embodiments of the liquid crystal optical element of the present invention will be described in detail with reference to FIGS. Embodiments 1 to 5 are liquid crystal optical elements that are inserted into an optical system of a pickup device used for reading and writing optical disks such as CDs, DVDs, and BDs. Among various modifications of the liquid crystal optical element for the pickup device, the first to fourth embodiments are two-layer liquid crystal cells, and the upper liquid crystal cell including the first substrate, the second substrate, and the first liquid crystal layer is optical. As a λ / 4 retardation plate that corrects the spherical aberration of the system, and the lower liquid crystal cell including the second substrate, the third substrate, and the second liquid crystal layer converts linearly polarized light into circularly polarized light (and performs reverse conversion). Function. FIG. 10 shows an embodiment in which the liquid crystal optical element of the present invention is applied to a pickup device. In addition, the same code | symbol is attached | subjected to the same or an equivalent element, and the overlapping description is abbreviate | omitted.
(Embodiment 1)

  A first embodiment will be described with reference to FIGS. FIG. 3 is a cross-sectional view (a) and a plan view (b) of the liquid crystal optical element of the first embodiment. FIG. 4 is a cross-sectional view taken along line CD in FIG. FIG. 5 is a plan view showing electrodes of the liquid crystal optical element of FIG. FIG. 6 is an explanatory diagram of a process of connecting the electrodes of the liquid crystal optical element with the isolated conductive member of FIG.

  With reference to FIG. 3A, the lamination state of members in the liquid crystal optical element of Embodiment 1 will be described. A second substrate 302 and a first substrate 301 are sequentially stacked on the third substrate 303. A first liquid crystal layer (not shown) is sandwiched between the first substrate 301 and the second substrate 302. Similarly, a second liquid crystal layer (not shown) is sandwiched between the second substrate 302 and the third substrate 303. The second substrate 302 extends to the left side of the drawing with respect to the first substrate 301. Further, the third substrate 303 extends from the second substrate 302. A plurality of first electrodes (not shown) are formed on the upper surface of the extended portion of the second substrate 302. Similarly, a plurality of second electrodes (not shown) are also formed on the upper surface of the extended portion of the third substrate 303. The first electrode and the second electrode are connected one-to-one by a silver paste 306 (conductive member). On the right side of the figure, the second substrate 302 extends, and connection electrodes (not shown) with external circuits are formed on the upper surface of the extension part, and each connection electrode 308 is connected to the FPC 305 via an anisotropic conductive adhesive 304. Connect to wiring (not shown).

    The connection status of the liquid crystal optical element of Embodiment 1 will be described in more detail with reference to FIG. A silver paste 306 is disposed so as to straddle the extended portion of the third substrate 303 and the extended portion of the second substrate 302. A part of the first electrode 307 is exposed on the right side of the silver paste 306, and the remaining part of the first electrode 307 exists under the silver paste 306. The second electrode 309 is not shown because it is under the silver paste 306. In the extended portion of the second substrate 302 on the right side of the figure, a part of the connection electrode 308 can be seen between the FPC 305 and the first substrate 301. The remaining part of the connection electrode 308 is under the FPC 305.

    The liquid crystal cell structure of the liquid crystal optical element of Embodiment 1 will be described with reference to FIG. FIG. 4 is a cross-sectional view of the main part along the line CD in FIG. 3B, and shows a state before the silver paste 306 is applied or the FPC 305 is bonded. First, the upper liquid crystal cell will be described. A drive electrode 401 is formed on the lower surface of the first transparent substrate 301, and a part of the drive electrode 401 reaches the seal 406 region. On the upper surface of the second substrate 302, a first electrode 307a, a drive electrode 402, and a connection electrode 308b are formed. A first liquid crystal layer 405 is sandwiched in a space surrounded by the first substrate 301, the second substrate 302, and the seal 406. Next, the lower liquid crystal cell will be described. A drive electrode 403 is formed on the lower surface of the second transparent substrate 302, and a part of the drive electrode 403 reaches the seal 408 region. A second electrode 309 a and a drive electrode 404 are formed on the upper surface of the third substrate 303. A second liquid crystal layer 407 is sandwiched in a space surrounded by the second substrate 302, the third substrate 303, and the seal 408. Note that the drive electrode 401 and the connection electrode 308 b are electrically connected by conductive particles (not shown) kneaded in the seal 406. Similarly, the drive electrode 403 and the second electrode 309a are electrically connected by conductive particles (not shown) kneaded in the seal 408.

Each substrate 301, 302, 303 is made of 0.4 mm thick glass, and each electrode 307a,
308a, 309b, 401 to 404 are made of ITO having a thickness of 0.012 μm. The first liquid crystal layer 405 and the second liquid crystal layer 407 are vertically aligned in consideration of temperature characteristics, and have a thickness of 7 to 10 μm and 2 to 4 μm, respectively. A vertical alignment film (not shown) made of polyimide covers the surfaces of the drive electrodes 401 to 404 except for the seals 406 and 408.

    The electrode of this embodiment is demonstrated in FIG. 5, (a), (b), (c), and (d) show electrodes formed on the lower surface of the first substrate 301, the upper surface of the second substrate 302, the lower surface of the second substrate 302, and the upper surface of the third substrate 303, respectively. These are all viewed from the top side.

    In FIG. 5A, the drive electrode 401 has a circular region and a portion protruding from this region. The circular region is a region through which the laser beam of the pickup device passes and behaves as a common electrode (also referred to as a common electrode). The tip of the protruding portion of the drive electrode 401 reaches the seal 406.

    The liquid crystal optical element for correcting spherical aberration is such that the entire drive electrode has a circular drive electrode and a plurality of annular drive electrodes arranged concentrically. In FIG. 5B, the drive electrode 402c having a circular shape and two drive electrodes 402a and 402b having an annular shape are illustrated in a simplified manner. In the drawing, the right side of the upper surface of the second substrate 302 is an FPC connection region, and the connection electrodes 308a to 308f are arranged vertically. The connection electrode 308a is connected to the first electrode 307a so as to cross the substrate. The left end of the connection electrode 308b reaches the seal 406 region. The connection electrodes 308c, d, e are connected to the drive electrodes 402a, b, c, respectively. The connection electrode 308f is also connected to the first electrode 307b so as to cross the substrate.

    In FIG. 5C, the drive electrode 403 has a rectangular region and a portion protruding from this region. The rectangular area includes an area through which the laser beam of the pickup device passes, and the drive electrode 403 reaches the seal 408 at the tip of the protrusion.

    In FIG. 5D, the rectangular drive electrode 404 is connected to the second electrode 309b. There is a second electrode 309a at the top of the figure.

    When the second liquid crystal layer 407 functions as a phase difference plate, the amount of phase difference is determined by the voltage applied to the liquid crystal layer, so two electrodes (drive electrodes 403 and 404) for driving the liquid crystal layer 407 may be used. In other words, there are two terminals (second electrodes 309a and b) to which a drive signal is input. Further, the rectangular area of the drive electrode 403 and the rectangular area of the drive electrode 404 have the same shape.

    In a state where the liquid crystal cell is assembled, the connection electrode 308b is connected to the tip of the protrusion of the drive electrode 401 via the seal 406, and the tip of the protrusion of the drive electrode 403 is connected to the second electrode 309a via the seal 408. . A pair of the first electrode 307 a and the second electrode 309 a is connected by a silver paste 306. Similarly, a pair of the first electrode 307 b and the second electrode 309 b is connected by a silver paste 306.

    As described above, all the drive electrodes 401, 402 a to 403, 404 are connected by the vertical conduction by the seals 406 and 408 and the conduction between the first electrodes 307 a and b and the second electrodes 309 a and b by the silver paste 306. Connection electrodes 308a-f are connected.

In FIG. 6, a method of applying the silver paste 306 in this embodiment will be described. FIG. 6A shows the liquid crystal cell before the silver paste is applied as viewed from the side. In FIG. 6B, the silver paste 602 is pushed out from the dispenser 601 to the extended portion of the third substrate 303. The liquid crystal cell is moved to the left before the silver paste 602 is completely extruded. Since the dispenser 601 that has to control the exact amount of extrusion becomes a complicated mechanism, the dispenser 6
It is easier to move the liquid crystal cell than to move 01. When all the silver paste 602 is pushed out from the dispenser 601, the shape becomes such that the silver paste 306 straddles the extended portion of the second substrate 302 and the extended portion of the third substrate 303 as shown in FIG.
(Embodiment 2)

  Other embodiments 2 to 4 will be described with reference to FIGS. These Embodiments 2 to 4 are also liquid crystal optical elements for the pickup device, and members such as a drive electrode, a first liquid crystal layer, a second liquid crystal layer, and a silver paste coating method related to the internal structure of the liquid crystal cell are the same as those of the first embodiment. Since it is basically equivalent, only the appearance will be described.

  A second embodiment will be described with reference to FIG. FIG. 7 is a cross-sectional view (a) and a plan view (b) of the liquid crystal optical element of the second embodiment. As in the first embodiment, a second substrate 702 and a first substrate 701 are sequentially stacked on a third substrate 703, and a first liquid crystal layer (not shown) is interposed between the first substrate 701 and the second substrate 702. The second liquid crystal layer (not shown) is sandwiched between the second substrate 702 and the third substrate 703 (the same applies to the third to fifth embodiments).

In FIG. 7, the second substrate 702 extends to the left with respect to the first substrate 701 and the third substrate 703. Two first electrodes 707 are formed on the upper surface of the extended portion of the second substrate 702, and similarly, two second electrodes (not shown) are formed on the lower surface of the extended portion of the second substrate 702. Yes. A pair of the first electrode 707 and the second electrode is connected by a silver paste 706. On the right side of the drawing, the second substrate 702 extends, and a plurality of connection electrodes 708 are formed on the upper surface of the extension part, and each connection electrode 708 is connected to the FPC 705 via an anisotropic conductive adhesive 704 (not shown). Connect with.
(Embodiment 3)

Embodiment 3 will be described with reference to FIG. FIG. 8 is a cross-sectional view (a) and a plan view (b) of the liquid crystal optical element of the third embodiment. In FIG. 8, the second substrate 802 extends to the right side of the drawing with respect to the first substrate 801, and the third substrate 803 extends with respect to the second substrate 802. Two first electrodes 807 and connection electrodes 808 are formed on the upper surface of the extended portion of the second base 802. Similarly, two second electrodes (not shown) are formed on the upper surface of the extended portion of the third substrate 803. Is formed. A pair of the first electrode 807 and the second electrode is connected by a silver paste 806. On the upper surface of the extended portion of the second substrate 802, each connection electrode 808 is connected to a wiring (not shown) of the FPC 805 through an anisotropic conductive adhesive 804.
(Embodiment 4)

  A fourth embodiment will be described with reference to FIG. FIG. 9 is a cross-sectional view (a) and a plan view (b) of the liquid crystal optical element of the fourth embodiment. In FIG. 9, the second substrate 902 extends to the right side of the drawing with respect to the first substrate 901 and the third substrate 903. Two first electrodes 907 and a plurality of connection electrodes 908 are formed on the upper surface of the extended portion of the second substrate 902, and two second electrodes (not shown) are formed on the lower surface of the extended portion of the second substrate 902. Is formed. A pair of the first electrode 907 and the second electrode is connected by a silver paste 906 applied to a side orthogonal to the FPC connection region. On the upper surface of the extended portion of the second substrate 902, each connection electrode 908 is connected to the wiring (not shown) of the FPC 905 through the anisotropic conductive adhesive 904.

  As described above, in the liquid crystal optical elements according to the first to fourth embodiments of the present invention, the connection step with the external circuit is only required, and thus the connection process is extremely easy. In addition, since it is not necessary to use FPC, an adverse effect on other parts during thermocompression bonding, disconnection of wiring, or the like does not occur, and a highly reliable element can be realized.

  In addition, by using a conductive paste as the conductive member, a coating process is sufficient instead of a connection process such as FPC, which facilitates manufacturing.

Furthermore, by forming the connection electrode connected to the external circuit only on one substrate, the connection with the external circuit can be consolidated in one place, so that the connection process can be simplified (Embodiment 5).

    In FIG. 10, an example in which any one of the liquid crystal optical elements of Embodiments 1 to 4 is applied to a pickup device will be described. FIG. 10 is an explanatory diagram of an optical system of a pickup device including an optical disk. A laser beam 12 (broken line) emitted from the light source 11 is formed into a cylindrical shape by a collimator lens 13. The laser beam 12 passes through the polarization beam splitter 16 and enters the liquid crystal optical element 17. When passing through the liquid crystal optical element 17, the laser beam 12 first undergoes spherical aberration correction in the first liquid crystal layer and changes its wavefront, and then passes through the second liquid crystal layer corresponding to the λ / 4 phase difference plate to pass through the circularly polarized light. Then exit. The circularly polarized laser beam 12 is spotted on an optical disk (optical recording medium) 19 by an objective lens 18. When the laser beam 12 is reflected from the optical disk 19, the rotation direction of the circularly polarized light is reversed, and the laser beam 12 returns to the linearly polarized light by the second liquid crystal layer corresponding to the λ / 4 retardation plate. At this time (return path), the linear polarization direction of the laser beam 12 is orthogonal to the forward linear polarization direction, so that it passes through the first liquid crystal layer and is reflected by the polarization beam splitter 16. Finally, the laser beam 12 is collected by the lens 14 and enters the analyzer 15.

    Although Embodiments 1 to 4 have a two-layer liquid crystal cell configuration composed of three substrates, the method of the present invention can be applied to a multilayer liquid crystal cell composed of four or more substrates. In addition, the liquid crystal optical element of the present invention is not limited to the pickup device because it can be easily connected to an external circuit as a multilayer cell.

    Further, in the above embodiment, the wiring electrodes of the two extending portions are connected in a one-to-one relationship. However, the wiring electrodes of the three or more extending portions may be connected, and a multi-layered liquid crystal Applicable even to cells.

    In addition, the liquid crystal layer functioning as the retardation plate included in the first to fourth embodiments changes the applied voltage to be a λ / 4 wavelength plate for each of the CD laser wavelength, the DVD laser wavelength, and the BD laser wavelength. . That is, the optical system shown in FIG. 10 can cope with these three types of optical disks. Thus, although the function is improved, the connection by silver paste is completed at two places. Thus, when the liquid layer optical element of the present invention is applied to a pickup device, the practicality is increased by a simple method.

    In the first to fourth embodiments, the first liquid crystal layer is a spherical aberration correction element. However, the first liquid crystal layer may be an element that corrects astigmatism and coma aberration, and may be an element that simultaneously corrects these aberrations. When combining a plurality of types of corrections, the drive electrode on the first substrate side is divided. A Fresnel lens may also be incorporated. These lead to an increase in the number of drive electrodes, but if the liquid crystal layer and connection electrodes that require a large number of drive electrodes are arranged on the same substrate surface, the drive electrodes and connection electrodes can be connected without using silver paste, so that the wiring structure Simplify.

Moreover, although silver paste was used in Embodiments 1-4, as the conductive member, a conductive paste in which carbon black or copper particles are dispersed in a resin, or a conductive tape may be used. Further, although a dispenser (air dispenser) is used for applying the silver paste, an ink jet (jet dispenser), brush painting, or the like may be used. If the silver paste is exposed, it may be adversely affected by moisture. In this case, it is preferable to protect the silver paste with silicone or the like. A plurality of or singular first electrodes and a plurality of or singular second electrodes may be connected as a pair by a single conductive member. In the case of a three-layer cell, the third electrode, the first electrode, and the second electrode may be connected by a single conductive member. Alternatively, a through hole may be provided in the substrate extension, and a conductive member may be pushed into the through hole to connect the first electrode and the second electrode.

301, 701, 801, 901 ... first substrate,
302, 702, 802, 902 ... second substrate,
303,703,803,903 ... 3rd board | substrate,
304, 704, 804, 904 ... anisotropic conductive adhesive,
305,705,805,905 ... FPC,
306,706,806,906 ... silver paste (conductive member),
307, 307a-b, 707, 807, 907 ... first electrode (wiring electrode),
308, 308a-f, 708, 808, 908 ... connection electrodes,
309, 309a-b ... second electrode (wiring electrode),
401-404, 402a-c ... drive electrode, 405 ... first liquid crystal layer, 406, 408 ... seal, 407 ... second liquid crystal layer.

Claims (4)

In a liquid crystal optical element in which a liquid crystal layer is sandwiched in each gap between three or more substrates to be stacked, and the liquid crystal layer is driven by energization with an external circuit,
One of the two substrates facing each other across the liquid crystal layer is provided with an extending portion that extends outward from the outer edge of the other substrate.
A wiring electrode is provided on the surface exposed to the outside in the extended portion,
The liquid crystal optical element, wherein the wiring electrodes of at least two of the extending portions are connected one to one by a conductive member.   The liquid crystal optical element according to claim 1, wherein the conductive member is a conductive paste.   The liquid crystal optical element according to claim 1, wherein a connection electrode connected to the external circuit is formed only on one of the substrates to be laminated. In a pickup device for condensing a laser beam emitted from a light source onto an optical recording medium and detecting the laser beam reflected by the optical recording medium,
A pickup apparatus comprising the liquid crystal optical element according to claim 1 on an optical path of the laser beam.

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