JP2002258314A - Liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device having highly accurate outside dimensions and stuck to a flexible circuit board with excellent conductivity. SOLUTION: The liquid crystal device is provided with a liquid crystal panel 20 constructed by placing a first transparent electrode formed on a surface of a lower glass plate 1 and a second transparent electrode formed on a surface of an upper glass plate 2 opposite to each other, by sealing a gap provided between the lower glass plate 1 and the upper glass plate 2, by injecting a liquid crystal into the gap and by end-sealing the injection port, a flexible printed circuit board FPC 15 connected to the first transparent electrode and the second transparent electrode and guards 32, 33 to prevent a conductive adhesive from protruding to a specified direction on the lower glass plate 1 in the case the lower glass plate 1 and the FPC 15 are stuck together via the conductive adhesive comprising an insulating adhesive with conductive particles mixed therein on an extended part 5 on the lower glass plate 1 exiting from the upper glass plate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device utilizing the optical function of liquid crystal, and more particularly to a liquid crystal panel having a liquid crystal sealed between two transparent substrates having transparent electrodes formed on the surface thereof, and a flexible printed circuit board. And a liquid crystal device bonded with an anisotropic conductive adhesive.

[0002]

2. Description of the Related Art In recent years, liquid crystals have been widely used as display devices, but have also come to be used as devices utilizing the optical functions of liquid crystals. For example, DVD (Digi
In general, an optical pickup of a tal Video Disc has a fixed optical system including a semiconductor laser, a phase beam splitter (PBS) and the like, and a moving optical system including a prism and an objective lens. The light emitted from the semiconductor laser is radiated to the surface of the DVD via a fixed optical system and a moving optical system, and the reflected light is received via the moving optical system and the fixed optical system.

At the time of this light reception, if the DVD has a disc tilt (inclination due to the warpage of the disc), an aberration of the objective lens occurs and an error occurs in the pickup. In order to correct this aberration, there is a moving optical system provided with a liquid crystal device described below. This is based on the fact that the liquid crystal has a function of controlling the phase of light. This liquid crystal device consists of a liquid crystal panel and a flexible printed circuit board (Flexible Printed Circuit) that connects external circuits to the liquid crystal panel.
t, hereinafter referred to as FPC), provided with separated symmetrical pattern electrodes in the liquid crystal panel of one of the substrates constituting the liquid crystal panel, and the liquid crystal is driven in opposite directions by these symmetrical pattern electrodes so that the phase of light is changed. The correction is performed. In the liquid crystal panel, a transparent substrate (referred to as lower glass) having at least a transparent electrode having the symmetric pattern electrode formed on a surface thereof and a transparent substrate (referred to as upper glass) having a second transparent electrode are opposed to each other. A gap is provided and sealing is performed, and liquid crystal is sealed in the gap.
The liquid crystal panel and the FPC have the same width as the upper glass, and an anisotropic conductive adhesive (Anisotoripic Conduct Conductor) at one extension of the lower glass extending on both sides of the upper glass at right angles to the width.
ive Film (hereinafter referred to as ACF).

[0004]

Since this liquid crystal device is used for an optical system, it is required to have an external dimensional accuracy, and the lower glass is connected to the lower glass via an ACF at the extending portion from the upper glass.
When adhering to a PC, if the ACF is excessive, the ACF protrudes outside the lower glass and a projection is generated. Therefore, there is a problem that the outside dimension accuracy range of the liquid crystal device is exceeded. In addition, since the conductive particles contained in the ACF are insufficient, there is a problem in that sufficient conductivity and adhesive strength cannot be ensured between the transparent electrode of the lower glass and the FPC, so that bonding cannot be performed.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a liquid crystal device formed within the accuracy of external dimensions and bonded with sufficient conductivity between the transparent electrode of the lower glass of the liquid crystal panel and the FPC. The purpose is to provide.

[0006]

A liquid crystal device according to the present invention, which achieves the above object, comprises a first substrate having a first electrode formed on a surface thereof and a second substrate having a second electrode formed on a surface thereof. A liquid crystal panel in which a second electrode is opposed to one electrode, a gap is provided and sealed, and a liquid crystal is sealed in the gap;
A flexible printed circuit board connected to the electrodes,
An extension of the first substrate from the second substrate;
When bonding the substrate and the flexible printed circuit board via a conductive adhesive in which conductive particles are mixed into an insulating adhesive, the conductive adhesive does not protrude in a predetermined direction of the first substrate. And a guard for preventing such a situation.

In the liquid crystal device according to the present invention, the predetermined direction is an outer peripheral direction of the first substrate. In the liquid crystal device according to the present invention, the predetermined direction is an inside direction within a predetermined range in the extension of the first substrate. In the liquid crystal device according to the present invention, the guard prevents the conductive adhesive from protruding outside the first substrate from the outer periphery of the flexible printed circuit board, and the inside of the first substrate. The present invention is characterized in that the flexible circuit board is prevented from protruding from the outer periphery of the flexible circuit board facing a predetermined range in the extension portion.

In the liquid crystal device according to the present invention, the guard is provided on the flexible printed circuit board. In the liquid crystal device according to the present invention, the guard is a dummy electrode provided on the flexible printed circuit board.
In the above liquid crystal device of the present invention, the guard is provided with a sealant for sealing the first substrate and the second substrate on the first substrate.

In the liquid crystal device according to the present invention, the guard is formed in such a shape that the conductive adhesive easily flows along the guard during the bonding.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a view showing a liquid crystal device 10 according to one embodiment of the present invention, and FIG.
Is a plan view, (B) is a side view, FIG. 2 is an exploded perspective view of the liquid crystal panel 20 shown in FIG. 1, and FIG. 3 is a schematic perspective view of the lower glass 1 of the liquid crystal panel 20 shown in FIG. And
FIG. 4 is a perspective view of the upper glass 2 of the liquid crystal panel 20 shown in FIG. FIG. 5 is a side view of the liquid crystal panel 20 in which the liquid crystal 4 is sealed between the lower glass 1 and the upper glass 2.

1 to 5, reference numeral 1 denotes a first transparent substrate.
(Lower glass), 2 is a second transparent substrate (upper glass), 3 is a sealing member (sealant), 4 is a liquid crystal, 5 is an extending portion, and 6 is a conductor (whether silver or copper called a silver point is used. Or a conductive adhesive or anisotropic conductive adhesive in which conductive particles are mixed into an insulating resin), 9 is a sealing agent, 10 is a liquid crystal device, 15 is a flexible printed circuit board (FPC), 21, 2
2, 23 are first transparent electrodes, 24 is second transparent electrodes, 2
1 ', 22', 23 ', 25' are lead wires of the FPC 15, 32, 33 are dummy electrodes as guards, 50, 5
Reference numeral 1 denotes a symmetric pattern electrode. In FIG. 1A, a wiring pattern of a lead wire shown in FIG. 6 described later is shown in a see-through manner.

The lower glass 1 and the upper glass 2 have substantially the same width, and the lower glass 1 has extensions extending on both sides of the upper glass 2 in a direction perpendicular to the width. The extension 5 refers to one extension extending from the upper glass 2 on the lower glass 1. LCD panel 20
The liquid crystal 4 is sealed between a lower glass 1 having transparent electrodes 21, 22, 23 and leads 25 formed on the surface and an upper glass 2 having a transparent electrode 24 formed on the surface.
The liquid crystal device 10 includes a liquid crystal panel 20 and an FP
C15.

A liquid crystal panel 20 shown in FIG.
The transparent glass 21, 22 connected to the separated symmetrical pattern electrodes 50, 51, the other transparent electrode 23, and the lower glass 1 which is a transparent substrate formed on the surface and the common terminal shown in FIG. The transparent electrode 24 has the upper glass 2 formed on substantially the entire surface. By applying a voltage to the transparent electrodes 21 and 22 of the symmetric pattern electrodes 50 and 51, the liquid crystals are driven in opposite directions, and the phase correction of light is performed. These transparent electrodes are formed from an indium tin oxide (ITO) film.

As shown in FIGS. 3 and 5, in the liquid crystal panel 20, the surface of the lower glass 1 on which the electrodes 21, 22, and 23 are formed and the surface of the upper glass 2 on which the electrodes 24 are formed are opposed to each other. Then, a gap is provided and sealing is performed with the sealing agent 3, the liquid crystal 4 is injected into the gap, and then the opening 26 is sealed with the sealing agent 9. The lower glass 1 is provided with a lead 25 at a position facing the electrode 24 of the upper glass 2. The lead 25 on the lower glass 1 is connected to the electrode 24 of the upper glass 2 via the conductor 6. I have. Thus, all the electrodes to which the liquid crystal drive signal is to be supplied are all arranged on the lower glass 1.

The liquid crystal device 10 is a flexible printed circuit board connected to an external circuit and the transparent electrodes 21, 22, 23, and 24 disposed on the extension portion 5 of the lower glass 1 of the liquid crystal panel 20 formed as described above. (FPC) 15 and an anisotropic conductive adhesive (ACF) 16 (described later with reference to FIG. 8). The APC is performed between the FPC 15 and the lower glass 1 at the extension 5 of the lower glass 1.
A guard is provided to prevent the ACF 16 from sticking out of the adhesive in a predetermined direction of the lower glass 1, for example, in the outer peripheral direction when the bonding is performed through the adhesive 16. This guard will be described below with reference to FIGS.

FIG. 6 is a schematic diagram showing a first embodiment of the flexible printed circuit board shown in FIG. 1 as viewed from below.
In FIG. 6, (1) and (2) show portions corresponding to the lower glass 1 and the upper glass 2, respectively. The dummy electrodes 32 and 33 shown in FIG. 6 are provided using the electrode wiring of the FPC as the guard. That is, they are provided at the same time when the lead wires 31 of the FPC 15 are provided. The lead wires 31 (21 ', 22', 21 ', 22') of the FPC 15 corresponding to the transparent electrodes 21, 22, 23 and the lead portion 25 of the lower glass 1
23 ', 25'), dummy electrodes 32, 33 as guards are formed on the FPC 15. The dummy electrode 32 prevents the lower glass 1 from protruding in the outer peripheral direction,
A guard provided to keep the external dimensional accuracy of the liquid crystal device 10 within a predetermined range.
Reference numeral 15 denotes a guard provided so that the protrusion does not protrude from the inside of the place, that is, from the end of the lower glass 1. The dummy electrode 33 is a guard provided to prevent the protrusion of the anisotropic conductive adhesive ACF 15 from protruding inward of the lower glass 1, that is, to the upper glass 2 side. In this embodiment, the protrusion is prevented from protruding in a predetermined direction on the outer periphery of the FPC 15 by the dummy electrode 33. A hatched area 34 between the FPC 15 and the upper glass 2 on the lower glass 1 is an area for holding the liquid crystal device 10 when attaching the liquid crystal device 10 to the optical system, or attaching the liquid crystal device 10 to the optical system. This is an area used as a support for fixing. This dummy electrode 33 may not be provided depending on the application. In this embodiment, the dummy electrodes 32 and 33 are used as the guards.
One of the lead wires 31 corresponding to 1, 22, 23 and the lead portion 25 may also be used as a guard. Further, the dummy electrodes 32 and 33 may be provided on the lower glass 1.

FIG. 7 is a schematic diagram showing a second embodiment of the flexible printed circuit board shown in FIG. 1 as viewed from below.
In FIG. 7, (1) and (2) show portions corresponding to the lower glass 1 and the upper glass 2, respectively. The dummy electrodes 132 and 133 shown in FIG. 7 are provided using electrode wiring of an FPC as the guard. That is, the FPC 115
Are provided at the same time when the lead wire 131 is provided. In addition to the transparent electrodes 21, 22, 23 of the lower glass 1 and the lead wires 131 corresponding to the lead portions 25, dummy electrodes 132, 133 as guards are formed on the FPC 115. The dummy electrode 132 shown in FIG.
When the lower glass 5 and the lower glass 1 are bonded via the ACF 16, A
This is a guard provided to form the CF 16 into a shape that is easy to flow along the guard, and to prevent the ACF 16 from protruding from the outer periphery of the lower glass 1. The dummy electrode 133 is
This is a guard provided for the same purpose as the dummy electrode 33 in FIG. The hatched area 134 is the same application area as the area 34 in FIG.

FIG. 8 is a diagram showing a state in which the lower glass 1 of the liquid crystal panel 20 shown in FIG. 1 and the flexible printed circuit board 15 are connected. A liquid crystal panel 2 in which a liquid crystal 4 is sealed between a lower glass 1 and an upper glass 2 with a sealant 3 on a base 70.
Place 0. The lower glass 1 and the FPC 15 are connected by heating and pressing by the head 71 via the ACF 16 which is an anisotropic conductive adhesive.

FIG. 9 is a view showing a process of producing the liquid crystal device 10 shown in FIG. In the first step, in order to simultaneously produce nxm liquid crystal panels, indium tin oxide (IT) as a solid electrode for each liquid crystal panel is formed on the surface of the upper glass.
O) A film is formed, an insulating film is coated with SiO ₂ , an alignment film is formed, and alignment processing is performed. In the second step, n × m
(N rows and m columns) of the liquid crystal panel, the IT as a pattern electrode for each liquid crystal panel is formed on the surface of the lower glass.
An O film is formed, an alignment film is formed, and an alignment process is performed. In the third step, a sealant is seal-printed on the surface of the lower glass, and spacers (particles of about 7 to 8 μm) are sprayed. here,
In the first and second embodiments, since the guard is provided on the FPC, no sealant for guard is provided. In the third embodiment, a sealant for guard is provided on the lower glass 1. When a guard is provided with a sealant, the guard is formed in the same state as in the first and second embodiments. In the fourth step, the upper glass created in the first step and the lower glass created in the second step are thermocompression-bonded or crimped, and then cut into n strip cells. In the fifth step, liquid crystal is injected into each cell and sealed with a sealing agent to obtain n liquid crystal panels. Here, a cell refers to a state in which liquid crystal is not injected into a liquid crystal panel.

In the sixth step, the n obtained in the fifth step
Each liquid crystal panel is cut into individual liquid crystal panels. In the seventh step, the FPC on which the pattern electrode, the common electrode, and the dummy electrode for guard are formed is adhered to the lower glass of the liquid crystal panel with the anisotropic conductive adhesive ACF as described above to establish electrical continuity. Here, in the first and second embodiments, the guard dummy electrode is provided on the FPC, and in the third embodiment, the sealant is provided on the lower glass for guard. Then, the lower glass and the FPC are heat-pressed via the ACF.

FIG. 10 is a view showing an embodiment of the lower glass in the liquid crystal device 10 according to the second embodiment of the present invention. FIG.
As shown in (3), in the third embodiment, the above-described guard is configured by providing a sealant 41 for sealing the lower glass 1 and the upper glass 2 on the lower glass 1 when the lower glass 1 is formed. When the FPC 15 and the lower glass 1 are bonded to each other via the ACF 16 at the extension 24 of the lower glass 1, the sealant 42 on the lower glass 1
Is a guard provided to prevent the outer periphery of the outer periphery from protruding in a predetermined direction. This sealant 42 may not be provided depending on the application.

FIG. 11 shows a DVD equipped with the liquid crystal device of the present invention.
FIG. 2 is a schematic configuration diagram of an optical pickup of FIG. An optical pickup 100 shown in FIG. 11 includes a semiconductor laser 101, a collimating lens (not shown), and a phase beam splitter (P
BS) 102, detection lens 103 and light receiving element 104
And a movable optical system 110 including a prism 106, a liquid crystal device 107, a λ / 4 plate 108, an objective lens 109, and the like. The moving optical system 110 moves in the radial direction of the DVD 111 to optically pick up the entire recording area of the rotating DVD 111. Light emitted from the semiconductor laser 101 is transmitted through a collimating lens, a PBS 102, a prism 106, a liquid crystal device 107,
DV via the λ / 4 plate 108 and the objective lens 109
D111 is emitted to the surface of D111 and the reflected light is
09, λ / 4 plate 108, liquid crystal device 107, prism 10
6, light is received by the light receiving element 104 via the PBS 102 and the detection lens 103.

The liquid crystal device 107 utilizes the fact that the liquid crystal has a function of controlling the phase of light,
If the disc 111 has a disc tilt (inclination due to the warpage of the disc), an aberration of the objective lens 108 occurs and an error occurs in the pickup. Therefore, the objective lens 108 is provided to correct this aberration. As described above, according to the present invention, there is provided a liquid crystal device formed within the range of the external dimension accuracy and bonded with sufficient conductivity between the transparent electrode of the lower glass of the liquid crystal panel and the FPC. it can.

The embodiments of the present invention have been described above with reference to a liquid crystal device for correcting aberrations of an objective lens. However, the present invention is applicable to a liquid crystal television receiver and a liquid crystal panel for a telephone if the adhesive is to be prevented from protruding. It can also be applied to panels such as a liquid crystal printer and a liquid crystal monitor, and an effect can be obtained. Further, the present invention can be applied to a reflection type liquid crystal panel, and the electrode at that time may be a reflection electrode. If a color filter or a protective film is used in the liquid crystal device, the effect of the present invention can be obtained even if these members are used as a guard.

[Brief description of the drawings]

FIG. 1 is a view showing a liquid crystal device according to an embodiment of the present invention, wherein (A) is a plan view and (B) is a side view.

FIG. 2 is an exploded perspective view of the liquid crystal panel shown in FIG.

FIG. 3 is a schematic perspective view of a lower glass of the liquid crystal panel shown in FIG.

4 is a perspective view of an upper glass of the liquid crystal panel shown in FIG. 2 as viewed from a surface facing a lower glass.

FIG. 5 is a side view of the liquid crystal panel shown in FIG.

FIG. 6 is a schematic view showing a first embodiment of the flexible printed circuit board shown in FIG. 1 as viewed from below.

FIG. 7 is a schematic diagram showing a second embodiment of the flexible printed circuit board shown in FIG. 1 as viewed from below.

8 is a diagram showing a state in which the liquid crystal panel shown in FIG. 1 is connected to a flexible printed circuit board.

FIG. 9 is a diagram showing a process of manufacturing the liquid crystal device shown in FIG.

FIG. 10 is a view showing an example of a lower glass in the liquid crystal device according to the second embodiment of the present invention.

FIG. 11 is a schematic configuration diagram of a DVD optical pickup including the liquid crystal device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st transparent substrate 2 ... 2nd transparent substrate 3 ... Seal member (sealant) 4 ... Liquid crystal 5 ... Extension part 6 ... Conductor (silver point) 9 ... Sealant 10 ... Liquid crystal device 15 ... Flexible printed circuit Substrate (FPC) 16 ... Anisotropic conductive adhesive (ACF) 20 ... Liquid crystal panel 21, 22, 23 ... First transparent electrode 24 ... Second transparent electrode

Claims (8)

[Claims] 1. A first substrate having a first electrode formed on a surface thereof and a second substrate having a second electrode formed on a surface thereof are sealed by providing a gap between the first electrode and the second electrode. A liquid crystal panel having liquid crystal sealed in the gap; a flexible printed circuit board connected to the first electrode and the second electrode; and an extension of the first substrate from the second substrate, First
When bonding the substrate and the flexible printed circuit board via a conductive adhesive in which conductive particles are mixed into an insulating adhesive, the conductive adhesive does not protrude in a predetermined direction of the first substrate. A liquid crystal device comprising: 2. The liquid crystal device according to claim 1, wherein the predetermined direction is an outer peripheral direction of the first substrate. 3. The liquid crystal device according to claim 1, wherein the predetermined direction is an inside direction within a predetermined range in the extension of the first substrate. 4. The guard prevents the conductive adhesive from sticking out of the outer periphery of the flexible printed circuit board outside the first substrate, and prevents the conductive adhesive from extending outside the first substrate. The liquid crystal device according to any one of claims 1 to 3, wherein the liquid crystal device is prevented from protruding from an outer periphery of the flexible circuit board facing a predetermined range in the protrusion. 5. The liquid crystal device according to claim 1, wherein the guard is provided on the flexible printed circuit board. 6. The liquid crystal device according to claim 5, wherein the guard is a dummy electrode provided on the flexible printed circuit board. 7. The guard according to claim 1, wherein the guard is provided between the first substrate and the second substrate.
The liquid crystal device according to any one of claims 1 to 4, wherein a sealant for sealing with the substrate is provided on the first substrate. 8. The liquid crystal device according to claim 1, wherein the guard is formed in a shape in which the conductive adhesive easily flows along the guard during the bonding.