JP2009258145A - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element for achieving both of high display quality and cost reduction while providing functions of a touch panel. <P>SOLUTION: The liquid crystal display element includes a liquid crystal display cell 10 and a compensation cell 20 arranged opposite to the liquid crystal display cell 10 in order to improve the optical characteristics of the liquid crystal display cell 10. The compensation cell 20 includes: an upper side compensation glass 21 and a lower side compensation glass 22 which are arranged opposite to each other; an electrostatic capacity type touch panel transparent electrode 23 arranged on an inner surface of the compensation glass 21; a transparent insulating film 24 formed on the touch panel transparent electrode 23; and a first heater transparent electrode 25 formed on the transparent insulating film 24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element having a function as a liquid crystal module and a touch panel.

  This type of liquid crystal display element includes a display liquid crystal panel and a color tone correction liquid crystal panel arranged opposite to the display liquid crystal panel, and the color tone correction liquid crystal panel also serves as a resistive film type touch panel. is there.

  In the color correction liquid crystal panel, two glasses are arranged to face each other with a spacer material in between, and liquid crystal is sealed between the two glasses. Transparent conductive films to be a movable electrode and a fixed electrode of the touch panel are attached to the inner facing surfaces of both glasses.

  In other words, when the surface of the color correction liquid crystal panel is pressed with a finger, the glass is deformed by the pressure, and the movable electrode and the fixed electrode are partially in contact with each other. By doing so, the pressed position on the surface of the color correction liquid crystal panel can be detected (for example, Patent Document 1).

JP-A-3-11514

  However, when the surface of the color correction liquid crystal panel is pressed with a finger, the glass is deformed together with the spacer material and the thickness of the glass is partially reduced. As a result, there is an optical compensation relationship by the color correction liquid crystal panel. There is an essential drawback that it collapses and the display quality is extremely lowered. Further, the gap length between the two glasses is generally about several μm, and there is another drawback that the spacer material for maintaining this is easily deformed due to aging and has low durability. Unless these problems are solved, it is difficult to put them into practical use.

  The present invention was created under the above-described background, and the object of the present invention is to achieve both high display quality and low cost while having the function as a touch panel. The object is to provide a liquid crystal display element.

  In order to solve the above problems, a liquid crystal display element according to the present invention includes a liquid crystal display cell and a compensation cell disposed opposite to the liquid crystal display cell to improve the optical characteristics of the liquid crystal display cell. Is an upper transparent plate and a lower transparent plate that are arranged opposite to each other, a transparent electrode for a capacitive touch panel provided on the inner surface of the upper transparent plate, and a transparent provided on the transparent electrode for the touch panel It has an insulation part and the 1st transparent electrode for heaters provided on this transparent insulation part.

  In the case of this liquid crystal display element, when a finger touches the surface of the upper transparent plate of the compensation cell, a capacitor is formed between the finger and the transparent electrode for a touch panel formed on the inner surface of the upper transparent plate. A weak current is passed through the finger through the capacitor and a change in the current is detected, whereby the position where the finger is touched is detected. As described above, the compensation cell is configured not only to improve the optical characteristics of the liquid crystal display cell but also to function as a touch panel, thereby achieving both high display quality and low cost of the liquid crystal display element. It becomes possible. In addition, the liquid crystal of the liquid crystal display element can be warmed by passing a current through the transparent electrode for the first heater. For this reason, the change in the viscosity of the liquid crystal due to the change in the outside air temperature can be further suppressed, and the display quality of the liquid crystal display element can be improved.

  Further, in the present liquid crystal display element, the first transparent electrode for heater and the transparent electrode for touch panel are integrally provided in the compensation cell via the transparent insulating portion, so that the outer surface of the upper transparent plate of the compensation cell The touch panel transparent plate can be omitted as compared with the case where the touch panel transparent electrode and the touch panel transparent plate are stacked on top. For this reason, it is possible to prevent the display quality from being deteriorated due to the effect of light transmission / reflection, etc. due to the use of the transparent plate for a touch panel or the occurrence of Newton rings. Moreover, since the transparent plate for touch panels is unnecessary, the cost of the liquid crystal display element can be reduced.

  When the compensation cell further includes a second heater transparent electrode provided on the inner surface of the lower transparent plate, the second heater transparent electrode is connected to the first heater transparent electrode via a conductive member. It is preferable that they are connected. In this case, the liquid crystal of the liquid crystal display element can be heated not only by the first heater transparent electrode but also by the second heater transparent electrode. Therefore, the liquid crystal display element can be further improved in display quality.

  As for the compensation cell, for example, liquid crystal is preferably sealed between the upper transparent plate and the lower transparent plate, and the liquid crystal preferably contains 1% or less of a quaternary amine or other antistatic agent.

  When the antistatic agent is contained in the liquid crystal in the compensation cell as described above, the specific resistance of the liquid crystal becomes low, and even if static electricity is charged on the transparent plate of the compensation cell, the liquid crystal leaks. As a result, the liquid crystal rarely malfunctions due to static electricity. In addition, the content of the antistatic agent does not adversely affect the viscosity or deterioration of the liquid crystal. Therefore, it is possible to further improve the display quality of the liquid crystal display element in this aspect.

  The upper / lower transparent plates are preferably subjected to a rubbing treatment for keeping the molecular orientation of the liquid crystal constant. In this case, since the upper / lower transparent plate is rubbed, the direction of the molecular axis of the liquid crystal is unified, and the liquid crystal malfunctions due to static electricity even when the transparent plate of the compensation cell is charged with static electricity. Is almost gone. In this respect, it is possible to further improve the high display quality of the liquid crystal display element.

  The transparent insulating part is preferably formed of an inorganic or organic material.

  It is preferable that a peripheral electrode for touch panel is formed on the peripheral edge of the transparent electrode for touch panel by conductive paste printing or electroless plating.

  Hereinafter, embodiments of the liquid crystal display element of the present invention will be described with reference to the drawings. 1 is a schematic sectional view of a liquid crystal display element according to an embodiment of the present invention, FIG. 2 is a schematic sectional view of a compensation cell of the element, and FIG. 3 is a schematic sectional view of an upper portion of the compensation cell of the element. And it is a figure which shows the example at the time of a finger touching on the compensation cell.

  A liquid crystal display element 1 shown in FIG. 1 is a DSTN type (Double Layer two-layer type), and the liquid crystal display cell 10 is used to correct a phase shift between the liquid crystal display cell 10 and the light passing through the liquid crystal display cell 10. And a compensation cell 20 arranged opposite to each other. Details of each component will be described below. The liquid crystal display element 1 is a transmission type, and a light source such as a cold cathode tube disposed on the back side of the liquid crystal display cell 10 is not shown.

  The liquid crystal display cell 10 is a well-known STN type (Super Twisted Nematic) liquid crystal display panel in which liquid crystal is sealed between an upper display panel 11 and a lower display panel 12. Therefore, detailed description is omitted. A polarizing plate 40 is attached to the outer surface of the lower display panel 12.

  The compensation cell 20 not only improves the optical characteristics of the liquid crystal display cell 10 as described above but also has a function as a capacitive touch panel, and the front surface of the liquid crystal display cell 10 using the adhesive adhesive 30. Bonded to the side.

  As shown in FIGS. 1 to 3, the compensation cell 20 includes an upper compensation glass 21 (upper transparent plate) and a lower compensation glass 22 (lower transparent plate) that are arranged to face each other, and an inner surface of the upper compensation glass 21. The transparent electrode 23 for the touch panel formed on the transparent electrode 23, the transparent insulating film 24 (transparent insulating portion) formed on the lower surface of the transparent electrode 23 for the touch panel, and the first heater formed on the lower surface of the transparent insulating film 24. A transparent electrode 25, a second heater transparent electrode 26 formed on the inner surface of the lower compensation glass 22, a peripheral portion of the lower surface of the first heater transparent electrode 25, and a second heater transparent electrode 26 A conductive sealing material 27 (conductive member) that bonds the gap between the lower surface of the transparent electrode 23 for the touch panel and the transparent electrode 26 for the second heater, and upper compensation by the main sealing material 28. Glass And a liquid crystal 29 sealed between the 1 and the lower compensation glass 22.

  A polyimide alignment film is applied to the outer surfaces of the upper and lower compensation glasses 21 and 22, respectively. Then, the surface of the polyimide alignment film is rubbed in a certain direction with a cloth such as velvet, thereby performing a rubbing treatment. This is to unify the molecular orientation of the liquid crystal 29 and prevent the liquid crystal 29 from being disturbed by static electricity during touch panel operation. A polarizing plate 40 is stuck on the outer surface of the upper compensation glass 21 thus processed.

  As the liquid crystal 29, a general liquid crystal material such as Merck ZLI-4431 is used. In order to prevent malfunction due to static electricity during touch panel operation, the liquid crystal 29 contains an antistatic agent (not shown) such as a quaternary amine for reducing the specific resistance.

  The content of the antistatic agent in the liquid crystal 29 is about 10 ppm to prevent the static electricity charged on the surface of the compensation glass 21 from leaking to the extent that it does not cause a problem, while not adversely affecting the viscosity or deterioration of the liquid crystal 29 itself. It should be 1% or less. There are various types of materials for the liquid crystal 29, but their basic structures are similar, so a content of about 1% or less is sufficient.

  The touch panel transparent electrode 23 is a transparent conductive film formed by sputtering on substantially the entire region on the inner surface of the upper compensation glass 21. Indium tin oxide (ITO) is used as the material for the transparent electrode 23 for the touch panel.

  In addition, a plurality of touch panel peripheral electrodes 231 are formed on the peripheral edge of the lower surface of the touch panel transparent electrode 23.

  The touch panel peripheral electrode 231 is a single-layer or multi-layer low-resistance metal film formed by electroless Ni plating, silver paste printing, or the like on the peripheral portion of the touch panel transparent electrode 23. Ni, Ag, Al, Mo / Cr, etc. are used as the material of this metal film. Note that after the metal film is formed on the touch panel transparent electrode 23, the touch panel peripheral electrode 231 may be selectively etched.

  The touch panel peripheral electrode 231 is connected to a power source (not shown), and an alternating voltage of the same potential is applied to the touch panel transparent electrode 23 from both sides in the X and Y axis directions. For this reason, when the finger does not touch the upper compensation glass 21, no current flows through the touch panel transparent electrode 23.

  As shown in FIG. 3, when the finger touches the upper compensation glass 21, a capacitor is formed between the finger and the transparent electrode 23 for the touch panel, and the capacitance thereof changes. At this time, a weak current flows through the finger from both sides of the transparent electrode 23 for touch panel in the X and Y axis directions. The change of each current is detected by detection means (not shown), so that the X and Y axis positions where the finger touches the upper compensation glass 21 are detected. In FIG. 3, the polarizing plate 40 is not shown.

  The transparent insulating film 24 is formed in the central region of the lower surface of the touch panel transparent electrode 23. As the material of the transparent insulating film 24, an inorganic material such as silicon dioxide (SIO2) or an organic material such as acrylic is used.

  When the transparent insulating film 24 is silicon dioxide, it is formed in the central region by a physical method such as a vacuum deposition method or an ion plating method. When the transparent insulating film 24 is acrylic, it is formed in the central region by contact coating such as a spinner (rotary coating), roll coater, bar coater or the like or non-contact coating such as a slit coater.

  The first heater transparent electrode 25 is a transparent electrode film formed by sputtering over substantially the entire lower surface of the transparent insulating film 24. As the material for the first heater transparent electrode 25, ITO is used in the same manner as the touch panel transparent electrode 23.

  The conductive sealing material 27 includes a spacer and an adhesive for bonding the spacer to the first and second heater transparent electrodes 25 and 26. That is, the first and second heater transparent electrodes 25 and 26 are electrically connected to each other by being bonded to the spacer first and second heater transparent electrodes 25 and 26 with an adhesive.

  The second heater transparent electrode 26 is a transparent electrode film formed by sputtering over substantially the entire inner surface of the lower filling glass 22. As the material for the second heater transparent electrode 26, ITO is used in the same manner as the touch panel transparent electrode 23.

  The peripheral portion of the second heater transparent electrode 26 is connected to a power source. That is, the current output from the power source flows to the second heater transparent electrode 26, the conductive sealing material 27, and the first heater transparent electrode 25, and the first and second heater transparent electrodes 25, 26 Fever.

  The liquid crystal 29 of the compensation cell 20 and the liquid crystal of the liquid crystal display cell 10 are heated by the heat generated by the first and second heater transparent electrodes 25 and 26. For this reason, the change of the viscosity of the liquid crystal 29 of the compensation cell 20 and the liquid crystal of the liquid crystal display cell 10 due to the change of the outside air temperature is suppressed.

  In addition, when an electric current is passed through the first and second heater transparent electrodes 25 and 26, a transparent insulating film 24 is interposed between the first heater transparent electrode 25 and the touch panel transparent electrode 23. Therefore, the current flowing through the first heater transparent electrode 25 does not affect the touch panel transparent electrode 23.

  In the case of the liquid crystal display element 1 described above, when the upper compensation glass 21 of the compensation cell 20 is touched with a finger, a capacitor is formed between the finger and the transparent electrode 23 for the touch panel formed on the inner surface of the upper compensation glass 21. It is formed. The position where the finger is touched is detected by detecting a change in the current flowing through the finger via the capacitor. Thus, since the compensation cell 20 not only improves the optical characteristics of the liquid crystal display cell 10 but also functions as a touch panel, it is possible to achieve both high display quality and low cost of the liquid crystal display element 1. It becomes possible. In addition, the first and second heater transparent electrodes 25 and 26 generate heat, and the liquid crystal 29 in the compensation cell 20 and the liquid crystal in the liquid crystal display cell 10 are warmed, so that the liquid crystal 29 and the liquid crystal display cell 10 in the compensation cell 20 are heated. Since it can suppress that the viscosity of a liquid crystal changes with the influence of external temperature, the high display quality of the liquid crystal display element 1 can be achieved also in this point.

  Further, in the present liquid crystal display element 1, the first heater transparent electrode 25 and the touch panel transparent electrode 23 are integrally provided in the compensation cell 10 via the transparent insulating film 24. For this reason, compared with the case where a touch panel is comprised separately from the compensation cell 20 and laminated | stacked on the said compensation cell 20, the transparent plate for touch panels provided on the transparent electrode for touch panels is not required. Therefore, it is possible to prevent the display quality from being deteriorated due to the effect of light transmission / reflection, etc. due to the use of the transparent plate for touch panel or the occurrence of Newton rings. Moreover, since the transparent plate for touch panels is unnecessary, the cost of the liquid crystal display element 1 can be reduced.

  Further, the liquid crystal 29 of the compensation cell 20 contains the antistatic agent, and as described above, is hardly affected by static electricity. Therefore, the high display quality of the liquid crystal display element 1 is maintained, and high performance can be achieved.

  In addition, about the liquid crystal display element 1 of an above-described structure, it is not limited to the said embodiment, A design change is possible arbitrarily as long as it suits the meaning of a claim. Details will be described below.

  Although the liquid crystal display cell is of STN type, it can be similarly applied to a CSTN type (Color Super-Twist Nematic) or the like, and a reflective type may be used.

  For the compensation cell, the upper transparent plate and the lower transparent plate arranged opposite to each other, the transparent electrode for the capacitive touch panel provided on the inner surface of the upper transparent plate, and the transparent cell for the touch panel The design can be arbitrarily changed as long as the transparent insulating portion provided and the first transparent electrode for heater provided on the transparent insulating portion are provided.

  Therefore, the second transparent electrode for a heater and the conductive member can be omitted. In this case, a power source may be directly connected to the peripheral portion of the first heater transparent electrode.

  The transparent plate of the compensation cell is a compensation glass, but the design can be arbitrarily changed as long as it is a transparent plate. For example, a film substrate can be used.

  Although polyimide alignment films are applied to the outer surfaces of the upper and lower compensation glasses 21 and 22 and rubbed, respectively, whether or not this is performed is arbitrary. The liquid crystal 29 preferably contains 1% or less of a quaternary amine or other antistatic agent, but is not limited thereto.

  In addition, about the shape and material of each structural member of the said liquid crystal display element, a design change is arbitrarily possible as long as the same function is realizable.

It is typical sectional drawing of the liquid crystal display element which concerns on embodiment of this invention. It is a typical sectional view of a compensation cell of the element. It is a typical sectional view of the upper part of the compensation cell of the element, and is a figure showing an example when a finger touches the compensation cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 10 Liquid crystal display cell 11 Upper display glass 12 Lower display glass 20 Compensation cell 21 Upper compensation glass (upper transparent plate)
22 Lower compensation glass (lower transparent plate)
23 Transparent electrode for touch panel 24 Transparent insulating film 25 Transparent electrode for first heater 26 Transparent electrode for second heater 29 Liquid crystal

Claims (6)

A liquid crystal display cell;
In order to improve the optical characteristics of the liquid crystal display cell, a compensation cell disposed opposite to the liquid crystal display cell,
An upper transparent plate and a lower transparent plate in which the compensation cells are arranged to face each other;
A transparent electrode for a capacitive touch panel provided on the inner surface of the upper transparent plate;
A transparent insulating portion provided on the transparent electrode for the touch panel;
A liquid crystal display element comprising: a first heater transparent electrode provided on the transparent insulating portion. The liquid crystal display element according to claim 1,
The compensation cell further has a second transparent electrode for heater provided on the inner surface of the lower transparent plate,
The liquid crystal display element, wherein the second heater transparent electrode is connected to the first heater transparent electrode through a conductive member. The liquid crystal display element according to claim 1,
A liquid crystal display device, wherein a liquid crystal sealed between an upper transparent plate and a lower transparent plate contains 1% or less of a quaternary amine or other antistatic agent. The liquid crystal display element according to claim 1,
A liquid crystal display element, wherein the upper / lower transparent plates are each subjected to a rubbing treatment for making the molecular orientation of the liquid crystal constant. The liquid crystal display element according to claim 1,
The liquid crystal display element, wherein the transparent insulating portion is formed of an inorganic or organic material. The liquid crystal display element according to claim 1,
A liquid crystal display element, wherein a peripheral electrode for a touch panel is formed on a peripheral portion of the transparent electrode for a touch panel by conductive paste printing or electroless plating.

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