JP2005266596A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin touch panel integrated type liquid crystal display which has high light transmissivity and whose screen display is easy to see, by preventing smearing color and unevenness of display with push pressure at the inputting. <P>SOLUTION: The touch panel integrated type liquid crystal display, equipped with a touch panel having a couple of upper and lower substrates arranged opposite each other and a liquid crystal display panel in one body, has a sealant brought into firm contact with the lower substrate of the touch panel and a display-surface side substrate of the liquid crystal display panel at their outer peripheral parts to stack and support the lower substrate of the touch panel and the display-surface side substrate of the liquid crystal display panel across a slight gap and transparent liquid, which is injected between the lower substrate of the touch panel, and the display-surface side substrate of the liquid crystal display panel sealed with the sealant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a touch panel integrated liquid crystal display device having an input function using a touch panel.

  2. Description of the Related Art Conventionally, a liquid crystal display device having an input function using a touch panel, for example, as shown in FIG. An electrode pattern 27 is formed, and a dot spacer 32 made of an ultraviolet curable resin or the like is formed on the surface of the touch panel back surface side substrate 22 on which the touch panel electrode pattern 27 is formed. The touch panel 36 is manufactured by bonding the substrate 22 to the touch panel electrode pattern 27 with the double-sided adhesive tape 31 or the like facing each other.

  Thereafter, the liquid crystal display panel electrode pattern 28 is formed on the liquid crystal display panel display surface side substrate 23 and the liquid crystal display panel back surface side substrate 24, and the liquid crystal display panel display surface side substrate 23 and the liquid crystal display panel back surface side substrate 24 are formed. The liquid crystal display panel electrode pattern 28 is bonded through a sealing material 29 so as to face each other, and the low molecular liquid crystal material 30 is enclosed, and the liquid crystal display panel display surface side substrate 23 is opposite to the liquid crystal display panel electrode pattern 28. A polarizing plate 25 is pasted, a polarizing plate integrated reflector 26 is pasted on the opposite side of the liquid crystal display panel electrode pattern 28 of the substrate 24 on the back side of the liquid crystal display panel to produce a liquid crystal display panel 37, and the touch panel fabricated as described above. In general, an air layer 38 is provided between the liquid crystal display panel 37 and the liquid crystal display panel 37, and the periphery thereof is bonded and mounted with a double-sided adhesive tape or the like It was.

  As described above, in a conventional liquid crystal display device having an input function using a touch panel, an air layer 38 is provided between the touch panel 36 and the liquid crystal display panel 37 so that no pressing force is applied to the liquid crystal display panel 37. However, since the refractive index of light in the air layer 38 is significantly lower than the refractive index of light in the liquid crystal material 30 and the electrode substrates 21, 22, 23, and 24, only the air layer 38 is laminated. As a result, the light transmittance is attenuated by about 20%, and the contrast is remarkably lowered. Further, an example in which a liquid is sealed between the upper and lower substrates of the touch panel to improve the light transmittance is disclosed, but even if such a liquid sealed touch panel is used, air is interposed between the touch panel 36 and the liquid crystal display panel 37. Due to the presence of the layer 38, there was a limit to improving the light transmittance.

  In addition, a touch panel generally requires a transparent electrode film, specifically an ITO film, to be formed on the opposing surface of a pair of upper and lower substrates at a thin film level. Since a liquid crystal having a refractive index of about 1.5 is used, the liquid to be sealed in the touch panel with a liquid inside is about halfway between the refractive index of the substrate of 1.5 and the refractive index of the ITO film of about 1.9. It was necessary to enclose a liquid having a refractive index, and the problem of limiting the encapsulated liquid was met. Moreover, it is necessary to consider the balance of different refractive indexes of the substrate, the ITO film, and the liquid to be sealed, and there is a limit to improving the light transmittance of the touch panel itself.

  Furthermore, in a liquid-sealed touch panel, a liquid crystal cell that is placed on the bottom surface due to unintended bending or bending of the highly flexible input side substrate due to the difference in the orientation of the touch panel due to the viscosity and weight of the liquid sealed inside There is a problem that the screen of the display device is distorted. This problem in the case where the input side substrate is made of a transparent resin substrate has been remarkable.

  In order to solve such a problem, as shown in FIG. 5 as a first conventional example, a touch panel integrated liquid crystal display in which an adhesive layer 33 is provided and laminated between a touch panel 36 and a liquid crystal display panel 37. An apparatus is disclosed. (For example, refer to Patent Document 1 and Patent Document 2.) This is because an adhesive layer 33 made of a material whose light refractive index is close to that of the liquid crystal material 30 or the electrode substrates 21, 22, 23, 24 is provided between the touch panel 36 and the liquid crystal display panel 37. This is to prevent a decrease in contrast or the like.

  As a second conventional example, as shown in FIG. 6, a touch panel integrated liquid crystal display device in which a display surface side substrate of a liquid crystal display panel 36 and a lower substrate of a touch panel 37 are configured by a single substrate 34 is disclosed. Has been. (For example, refer to Patent Document 3). This is to reduce the overall thickness of the touch panel integrated liquid crystal display device by configuring the display surface side substrate of the liquid crystal display panel 37 and the lower substrate of the touch panel 36 by a single substrate 34.

  Although not shown as a third conventional example, the display surface side substrate of the liquid crystal display panel 37 and the back surface side substrate of the touch panel 36 are configured by a single substrate 34 as in the second conventional example. A touch panel integrated liquid crystal display device using a ferroelectric polymer liquid crystal material is disclosed. (For example, refer to Patent Document 4). This is to prevent display blur due to stress deformation during touch panel input.

JP 61-131314 (2nd page, FIG. 2) JP-A-10-260395 (page 2-3, FIG. 1) Japanese Unexamined Patent Publication No. Hei 4-243412 (page 2-3, FIG. 1) JP-A-8-234162 (page 3-4, FIG. 1)

  However, in the touch panel integrated liquid crystal display device according to the first conventional example, when input is performed with respect to the touch panel 36 with a pen or the like, stress concentration occurs at a pinpoint. Since a pressing force is also applied to the liquid crystal display panel 37 through the year conception 33, a TN (twisted nematic) mode or a STN (super twisted nematic) mode using a low-molecular liquid crystal material by the pressing force. There is a problem that display blur or color unevenness occurs in the liquid crystal display panel 37 which is a display mode such as the above.

  In the touch panel integrated liquid crystal display device according to the second conventional example, the problem of the gap between the touch panel and the liquid crystal display panel is solved. However, when input is made to the touch panel 36 with a pen or the like, the liquid crystal display Since a pressing force is directly applied to the common substrate 34 which is the upper substrate of the panel 37, when stress concentration still occurs, the TN mode or STN mode using a low-molecular liquid crystal material is caused by the pressing force. There is a problem in that display blur and color unevenness occur on the liquid crystal display panel 37 in the display mode.

  Moreover, in the touch panel integrated liquid crystal display device according to the third conventional example, it is possible to prevent display blurring and color unevenness even when a pressing force is applied, but the liquid crystal material used for the liquid crystal display panel 37 is highly ferroelectric. There is a problem that the range that can be applied as a product is narrowed because it is limited to molecular liquid crystal materials.

(Object of invention)
An object of the present invention has been made in view of the above problems, and is a thin touch panel integrated liquid crystal that prevents the occurrence of uneven color in the display due to the pressing force at the time of input, and has high light transmittance and easy to see the screen display. An object is to provide a display device.

  In order to achieve the above object, a touch panel integrated liquid crystal display device according to the present invention is a touch panel integrated liquid crystal display device integrally including a liquid crystal display panel and a touch panel having a pair of upper and lower substrates opposed to each other. A sealing agent that adheres closely to the outer periphery of the lower substrate and the display surface side substrate of the liquid crystal display panel, and stacks and supports the touch panel lower substrate and the display surface side substrate of the liquid crystal display panel with a slight gap therebetween, A transparent liquid injected between the lower substrate of the touch panel sealed with the sealant and the display surface side substrate of the liquid crystal display panel is provided.

Further, the refractive index of the transparent liquid is approximately equal to the refractive index of the substrate of the touch panel.
The sealing agent has an injection port, and the injection port is sealed after the transparent liquid is injected from the injection port.
The sealing agent is made of an elastic epoxy resin.
In addition, a polarizing plate or a retardation plate is provided on the upper surface of the upper substrate of the touch panel.

  As described above, according to the touch panel integrated liquid crystal display device of the present invention, a thin touch panel integrated liquid crystal display that has no light bleeding and color unevenness due to pressing force at the time of input, has high light transmittance, and is easy to see the screen display. An apparatus can be provided.

The present invention is an idea similar to a liquid-sealed touch panel in the effect of improving the light transmittance, but the liquid-sealed touch panel is limited by the difference between the refractive index of the transparent electrode layer and the refractive index of the upper and lower substrates. In the present invention, the light transmittance can be remarkably improved by enclosing a liquid having a refractive index substantially equal between the liquid crystal panel upper substrate and the touch panel lower substrate having the same refractive index. Since the liquid can be in direct contact with the substrate surface on which the transparent electrode layer is not formed, the same material, for example, glass, is used for the liquid crystal panel upper substrate and the touch panel lower substrate, and a liquid having a refractive index equal to that of the glass is sealed. For example, the light transmittance of this portion can be as close as possible to 100%, and a light transmittance better than that of a liquid-sealed touch panel can be obtained.
Of course, if a liquid-filled touch panel is used in the touch panel integrated liquid crystal display device of the present invention, the light transmittance can be further improved.

  Further, in the liquid filled touch panel, the gap size between the upper and lower substrates, that is, the gap between the liquid filled portions, is restricted in terms of function by the touch panel method and the substrate material. For example, when the input substrate is a film in a resistive touch panel, the substrate interval needs to be controlled to 50 to 150 μm, and when glass is 10 μm. However, since the touch panel integrated liquid crystal display device of the present invention does not have such a restriction, the thickness dimension of the touch panel integrated liquid crystal display device does not increase unnecessarily as long as the pressing force at the time of touch panel input is not transmitted to the liquid crystal panel. Since it is possible to set the size so that liquid can be easily sealed in the range, an effect that it is easy to manufacture can be obtained.

  Furthermore, in the present invention, since the liquid is sealed between the liquid crystal panel upper substrate in which the liquid crystal substance that is liquid from the beginning is sealed and the touch panel upper substrate that is difficult to bend, the difference in posture of the substrate due to the viscosity and weight of the liquid. A touch-panel-integrated liquid crystal display device that does not generate distortion, does not bleed, and is easy to see can be provided.

  Hereinafter, a touch panel integrated liquid crystal display device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view of a touch panel integrated liquid crystal display device according to the present embodiment, FIG. 2 is a diagram for explaining a method for manufacturing the touch panel integrated liquid crystal display device according to the present embodiment, and FIG. 2 (b) is a cross-sectional view taken along the line AA in FIG. 2 (a). 3A and 3B are diagrams for explaining a method of manufacturing the touch panel integrated liquid crystal display device according to the present embodiment. FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along line BB in FIG. It is a schematic diagram showing a cross section. Of the constituent elements of the touch panel integrated liquid crystal display device according to the present embodiment, those similar to the constituent elements of the prior art are assigned the same reference numerals and description thereof is omitted.

  In order to obtain the touch panel 10 as shown in FIG. 1, glass having a thickness of 0.5 mm and a refractive index of 1.5 is used as the lower substrate 12, and ITO having a thickness of 100 nm is used as the transparent electrode 17 on the lower substrate 12. Form. Next, glass having a thickness of 0.2 mm and a refractive index of 1.5 is used as the upper substrate 11 on the input side, and ITO having a thickness of 100 nm is formed on the upper substrate 11 as the transparent electrode 17. After the transparent electrodes 17 formed on the lower substrate 12 and the upper substrate 11 have a predetermined electrode pattern, dot spacers 18 are formed by a photolithography method, and a sealant 16 is formed by a screen printing method. Next, the lower substrate 12 and the upper substrate 11 are bonded together with a predetermined gap. Thereafter, the polarizing plate 15 is attached to the surface of the upper substrate 11 to obtain the touch panel 10.

  The liquid crystal display panel 20 in the present embodiment is different from the liquid crystal display panel 37 in the prior art in that a polarizing plate is not provided on the upper surface of the display surface side substrate 23, and the other configurations are the same, and thus the description thereof is omitted.

  Next, as shown in FIG. 2, the sealant 13 is printed on the periphery of the display surface side substrate 23 of the liquid crystal display panel 20. At this time, an inlet 13 a for injecting the transparent liquid 19 into the sealing agent 13 is provided. The sealing agent 13 is for bonding the display surface side substrate 23 of the liquid crystal display panel 20 and the lower substrate 12 of the touch panel 10, and an epoxy resin adhesive or the like is selected and formed by a method such as screen printing. . A spacer member such as a plastic ball or fiber glass having a required size is dispersed in the sealant 13, and the spacer member serves to hold the display surface side substrate 23 and the lower substrate 12 at a required interval. Is made. Since the sealant 13 used here does not require high moisture resistance, the material of the sealant can be selected widely as long as the liquid sealed inside does not leak. In addition, if an elastic epoxy resin or the like is used as the sealing agent 13, the effect of absorbing impacts and vibrations from the outside, including during input from the touch panel, is further improved.

  Next, the display surface side substrate 23 of the liquid crystal display panel 20 and the lower substrate 12 of the touch panel 10 are overlapped via the sealant 13. Then, the sealing agent 13 is baked by pressurizing and heating for a predetermined time. As a result, the display surface side substrate 23 of the liquid crystal display panel 20 and the lower substrate 12 of the touch panel 10 are bonded together with the sealant 13. At this time, as shown in FIG. 3, a gap d is formed between the display surface side substrate 23 of the liquid crystal display panel 20 and the lower substrate 12 of the touch panel 10. The value of the gap d can be appropriately set in the range of 20 to 100 μm within a range in which the pressing force to the touch panel 10 is not transmitted to the display surface side substrate 23 of the liquid crystal display panel 20.

  Next, silicon oil having a refractive index of 1.4 is injected from the inlet as a transparent liquid 19 by a vacuum injection method. The transparent liquid 19 is not particularly limited as long as it has a refractive index equivalent to that of a liquid crystal display panel or touch panel substrate (around 1.5), such as a benzene ring-based liquid crystal material having a refractive index of 1.45. It is possible to use without being done. Thereafter, the inlet 13 a is sealed with a sealant 14. As the sealant 14 for sealing the injection port 13a, a photocurable adhesive such as an acrylic resin is used. This realizes a touch panel integrated liquid crystal display device in which a transparent liquid having a refractive index of about 1.5 is sealed between the display surface side substrate 23 of the liquid crystal display panel 20 and the lower substrate 12 of the touch panel 10.

As described above, according to the touch panel integrated liquid crystal display device in the present embodiment, the transparent liquid having a refractive index substantially equal to the substrate material of the liquid crystal display panel or the touch panel is applied to the display surface side substrate 23 of the liquid crystal display panel 20 and the touch panel 10. By enclosing between the lower substrate 12, high light transmittance can be obtained. Further, if the thickness of the transparent liquid to be sealed is 50 μm or more, the deflection of the touch panel is not transmitted to the liquid crystal display panel. Therefore, the touch panel is composed of the upper substrate 11 having a thickness of 0.2 mm and the lower substrate having a thickness of 0.5 mm. Can be used, and a touch panel integrated liquid crystal display device having a very thin and high light transmittance can be realized.
Moreover, since a polarizing plate, a phase difference plate, and the like are attached to the surface of the upper substrate 11 of the touch panel, it is possible to prevent the glass from being broken and scattered.

It is sectional drawing of the touchscreen integrated liquid crystal display device in embodiment of this invention. 2A and 2B are views for explaining a method of manufacturing a touch panel integrated liquid crystal display device according to an embodiment of the present invention, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along line AA in FIG. is there. 3A and 3B are diagrams for explaining a method of manufacturing a touch panel integrated liquid crystal display device according to an embodiment of the present invention, in which FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along line BB in FIG. is there. It is sectional drawing of the touchscreen integrated liquid crystal display device in a prior art. It is sectional drawing of the touchscreen integrated liquid crystal display device in a 1st prior art. It is sectional drawing of the touchscreen integrated liquid crystal display device in a 2nd prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Touch panel 11 Upper substrate 12 Lower substrate 13 Sealant 14 Sealant 15 Polarizer 16 Sealant 17 Transparent electrode 18 Dot spacer 19 Transparent liquid 20 Liquid crystal display panel 21 Touch panel display surface side substrate 22 Touch panel rear surface side substrate 23 Liquid crystal display panel display Surface side substrate 24 Liquid crystal display panel back side substrate 25 Polarizing plate 26 Polarizing plate 27 Touch panel electrode pattern 28 Liquid crystal display panel electrode pattern 29 Sealing material 30 Low molecular liquid crystal material 31 Double-sided adhesive tape 32 Dot spacer 33 Adhesive layer 34 Liquid crystal display panel Display-side substrate and touch-panel back-side substrate combined use 35 Ferroelectric polymer liquid crystal material 36 Touch panel 37 Liquid crystal display panel 38 Air layer

Claims (5)

In a touch panel integrated liquid crystal display device integrally including a touch panel having a pair of upper and lower substrates disposed opposite to each other and a liquid crystal display panel,
The bottom substrate of the touch panel and the display surface side substrate of the liquid crystal display panel are in close contact with each other, and the bottom substrate of the touch panel and the display surface side substrate of the liquid crystal display panel are stacked and supported with a slight gap. A touch panel integrated liquid crystal display comprising: a sealing agent for sealing; and a transparent liquid injected between a lower substrate of the touch panel sealed by the sealing agent and a display surface side substrate of the liquid crystal display panel apparatus.   2. The touch panel integrated liquid crystal display device according to claim 1, wherein a refractive index of the transparent liquid is substantially equal to a refractive index of a substrate of the touch panel.   2. The touch panel integrated liquid crystal display device according to claim 1, wherein the sealing agent has an inlet, and the inlet is sealed after the transparent liquid is injected from the inlet.   4. The touch panel integrated liquid crystal display device according to claim 1, wherein the sealant is made of an elastic epoxy resin.   3. The touch panel integrated liquid crystal display device according to claim 1, further comprising a polarizing plate or a retardation plate on an upper surface of the upper substrate of the touch panel.

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