JP2013250304A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device in which unevenness of a gap between substrates of a liquid crystal display element is suppressed while securing mechanical strength.SOLUTION: A liquid crystal display element 12 includes a non-facing part 24 on which a driver 28 and a flexible printed board 29 to be electrically connected with a display area are mounted at a position which does not face a counter substrate 22 of an array substrate 21. A lamination part 14 which mutually laminates the liquid crystal display element 12 and a touch panel 13 includes a first lamination part 33 provided by translucent resin by covering a part of the counter substrate 22. The lamination part 14 includes a second lamination part 34 provided by translucent resin with viscosity smaller than that of resin constituting the first lamination part 33 by covering at least the non-facing part 24 of the liquid crystal display element 12.

Description

  Embodiments described herein relate generally to a display device in which a display element and a touch panel are bonded together by a bonding unit.

  2. Description of the Related Art Conventionally, a liquid crystal display device (LCD) with a touch panel used as a multifunctional mobile terminal such as a smartphone is bonded to a liquid crystal display element (liquid crystal panel) that is a display element of the liquid crystal display device. It is comprised by pasting together.

  As such a bonding portion, for example, a so-called air gap method in which a liquid crystal display element and a touch panel are bonded along a peripheral position using a double-sided tape or the like, and a liquid crystal display element using a translucent resin are used. There are two types, a so-called lamination method, in which the entire surface of the touch panel is bonded. In the case of the air gap method, since an air layer exists between the liquid crystal display element and the touch panel, the visibility is reduced due to the reflection that occurs at the interface of the air layer, so the lamination method is adopted especially for high-performance devices. Often done.

JP 2009-25833 A

  In recent years, multi-function mobile terminals have become thinner, which may cause a problem of mechanical strength. For this reason, in the device using the lamination method, for example, it is easy to concentrate on the mounting position of the driver IC of the liquid crystal display element and the flexible substrate (COF) for external connection, for example, the impact when dropping is the weakest structurally. . For this reason, if the amount of resin for bonding is increased in order to increase the mechanical strength at this position, a position where the shrinkage amount of the resin is different in the bonding portion is generated. There is a possibility that gap unevenness between the array substrate and the counter substrate occurs at a position near the mounting position of the IC and the flexible substrate.

  The problem to be solved by the present invention is to provide a display device in which the unevenness of the gap between the substrates of the display elements is suppressed while ensuring the mechanical strength.

  The display device according to the embodiment includes a display element, a touch panel that transmits the display by the display element, and a bonding unit that bonds the display element and the touch panel together. The display element includes one substrate. In addition, the display element is arranged to face a part of the one substrate while maintaining a predetermined gap with respect to the one substrate, and the other element that forms a display region with the one substrate. A substrate is provided. Further, the display element is provided at a position where one substrate does not face the other substrate, and includes a peripheral portion on which a functional member electrically connected to the display region is mounted. The bonding portion includes a first bonding portion that is provided with a light-transmitting resin and is disposed so as to cover at least a part of the other substrate. Furthermore, the bonding portion includes a second bonding portion that is provided with a light-transmitting resin having a viscosity lower than that of the resin that forms the first bonding portion, and is disposed so as to cover at least the peripheral portion of the display element.

It is sectional drawing which shows the display apparatus of one Embodiment. (a) is a top view which shows the display element of a display apparatus same as the above, (b) is sectional drawing which shows a display element.

  Hereinafter, the configuration of an embodiment will be described with reference to FIGS. 1 and 2.

  1 and 2, reference numeral 11 denotes a display device. The display device 11 is a liquid crystal display device mounted on various multifunctional portable terminals such as a smartphone.

  The display device 11 includes a liquid crystal display element (LCD panel) 12 as a display element, a touch panel 13 covering the liquid crystal display element 12, and a bonding portion (lamination) for bonding the liquid crystal display element 12 and the touch panel 13 together. Part) 14 and a protective cover 15 as a protective member covering the touch panel 13.

  The liquid crystal display element 12 is, for example, an active matrix type reflective liquid crystal panel module, and has a square array substrate 21 as one substrate and the other array substrate 21 disposed opposite to the array substrate 21 with a predetermined gap. A rectangular counter substrate 22 as a substrate, a liquid crystal layer 23 that is a light modulation layer interposed between the substrates 21 and 22, and a polarizing plate (not shown) attached to the substrates 21 and 22 respectively. Yes.

  The array substrate 21 and the counter substrate 22 are formed in a thin flat plate shape (flat shape) by forming predetermined functional layers on a light-transmitting insulating substrate such as a glass substrate. Further, the counter substrate 22 has a width dimension substantially equal to that of the array substrate 21 and a longitudinal dimension smaller than that of the array substrate 21. That is, the counter substrate 22 has a smaller area than the array substrate 21.

  Further, the liquid crystal display element 12 has a sealing member (not shown) at the peripheral portion of the array substrate 21 and the counter substrate 22 in a state where the one end side of the counter substrate 22 is aligned with the one end side of the array substrate 21 in the longitudinal direction. It is constituted by pasting together. Therefore, the array substrate 21 includes a non-opposing portion 24 as a peripheral portion that does not face the counter substrate 22 at a position outside the other end portion in the longitudinal direction of the counter substrate 22. That is, in the liquid crystal display element 12, the position of the non-facing portion 24 is recessed from the surface position of the facing substrate 22 (and the polarizing plate), and the flatness is lost by the non-facing portion 24. In other words, the liquid crystal display element 12 is discontinuous with the thickness changing in a step shape at the position of the non-opposing portion 24. In the liquid crystal display element 12, a liquid crystal layer 23 is enclosed in a rectangular region surrounded by a seal member in which the array substrate 21 and the counter substrate 22 are bonded together, and a plurality of pixels (not shown) are matrixed. The display area 27 is configured by forming the shape.

  The display area 27 is entirely covered with, for example, a polarizing plate attached to the counter substrate 22. Each pixel located in the display area 27 is an IC as a functional member mounted on the array substrate 21 using an anisotropic conductive film (ACF) or the like with respect to the terminal pad provided in the non-facing portion 24. It is electrically connected to the driver 28, and is configured to be driven through the driver 28. The driver 28 has a thickness of about 200 to 300 μm, for example, and is substantially flush with the surface (display side surface) side of the counter substrate 22 including the polarizing plate. In addition, the driver 28 is connected as a functional member electrically connected to the array substrate 21 using an anisotropic conductive film or the like at the position of the connection portion 29a with the terminal pad provided in the non-facing portion 24. It is electrically connected to an external circuit by a flexible printed circuit board (FPC) 29, which is a member, and is controlled by this external circuit. This flexible printed circuit board 29 is mounted with a chip element (not shown) on a film-like insulating substrate having flexibility and being thinner than the array substrate 21, the counter substrate 22 and the driver 28, for example, having a thickness of about 100 μm. This is a so-called COF (Chip on film).

  The liquid crystal display element 12 can display an image or the like in the display region 27 by changing the reflectance of incident light for each pixel by driving the pixel by a driver 28 controlled by an external circuit. ing. Further, in the liquid crystal display element 12, a spacer 30 as a thickness difference suppressing member is disposed at a position excluding the driver 28 and the flexible printed board 29 in the non-facing portion 24 of the array substrate 21. The spacer 30 is formed in a film shape having a thickness of about 100 to 200 μm with a resin such as PET, for example, covers the connection portion 29a of the flexible printed circuit board 29 and avoids the driver 28, and substantially the entire non-opposing portion 24. Is pasted. That is, the spacer 30 is formed in a horizontally long rectangular shape in a plan view, and a rectangular notch 30a into which the driver 28 is fitted is formed on a side facing the end of the counter substrate 22. Yes. The spacer 30 allows the liquid crystal display element 12 to have a thickness difference between the position where the array substrate 21 and the counter substrate 22 face each other and the position where the array substrate 21 and the counter substrate 22 do not face each other (the non-opposing portion 24 including the driver 28 and the flexible printed circuit board 29). Then, the thickness difference between the non-opposing portion 24 and the counter substrate 22 side is suppressed, and is substantially zero. In other words, the spacer 30 is configured so that the thickness of the liquid crystal display element 12 is substantially constant throughout the entire area, and the flat area of the liquid crystal display element 12 is improved.

  The touch panel 13 is a capacitive type that detects the touch position of the user by detecting the capacitance that changes due to, for example, the approach or contact of a fingertip, for example, a translucent material such as a glass substrate. A lower transparent conductive film, an oxide film, an upper transparent conductive film, a protective film, and the like are formed on an insulating substrate. Further, the touch panel 13 is formed in the same size and shape (rectangular shape) in a plan view as the liquid crystal display element 12 (array substrate 21 of the liquid crystal display element 12), for example, the liquid crystal display element 12 and one end side are aligned. In this state, the liquid crystal display element 12 is bonded to the liquid crystal display element 12 by the bonding portion 14. In addition, a flexible printed circuit board (FPC) (not shown) is electrically connected to the touch panel 13 and is electrically connected to an external circuit by the flexible printed circuit board. Is controlled.

  The bonding portion 14 is formed using, for example, an acrylic UV curable resin having translucency, and the first bonding portion 33 positioned on the counter substrate 22 and the non-facing portion 24 are provided. And a second bonding portion 34 positioned. The bonded portion 14 as a whole has the same size and shape (rectangular shape) in plan view as the array substrate 21 and the touch panel 13 of the liquid crystal display element 12. In other words, the bonding portion 14 is formed to bond the entire display surface side of the liquid crystal display element 12 and the entire touch panel 13 together.

  The first bonding part 33 is formed in a square shape in plan view covering a position extending from one end of the counter substrate 22 to the vicinity of the other end, and is a part where the position and the touch panel 13 are bonded together.

  Further, the second bonding portion 34 is formed in a quadrangular shape in a plan view covering the position across the non-opposing portion 24 of the liquid crystal display element 12 and the other end side of the counter substrate 22, and a portion where the position and the touch panel 13 are bonded together It is. The second bonding portion 34 is formed continuously with the first bonding portion 33 without a gap.

  Here, the bonded portions 33 and 34 are formed to have substantially equal thicknesses of about 0.1 to 0.3 μm, for example. Further, the area of the first bonding portion 33 is larger than the area of the second bonding portion 34. Furthermore, these bonding portions 33 and 34 are formed of translucent resins having different viscosities (hardness), and the resin forming the second bonding portion 34 is more than the resin forming the first bonding portion 33. The viscosity (hardness) is set relatively small. Specifically, the viscosity of the synthetic resin forming the bonded portions 33 and 34 is, for example, in the range of 3000 to 4500 mPa · s, and the first bonded portion 33 having a relatively high viscosity within this range. One having a relatively low viscosity is used for the second bonding portion 34.

  The protective cover 15 is for protecting the touch panel 13 and the liquid crystal display element 12 from scratches, and is formed in a rectangular flat plate shape using a synthetic resin having translucency. Further, the protective cover 15 has, for example, a quadrangular shape having a longer dimension than the touch panel 13 and the liquid crystal display element 12, and the one end side is aligned with the touch panel 13 and the liquid crystal display element 12 on the surface side of the touch panel 13. It is pasted. The protective cover 15 may be appropriately printed to improve the design.

  Next, the assembly procedure of the one embodiment will be described.

  First, the array substrate 21 and the counter substrate 22 are formed by performing appropriate film formation and etching on the insulating substrate. Next, the substrates 21 and 22 are bonded to each other through a predetermined gap with a liquid crystal material forming the liquid crystal layer 23 interposed therebetween, or are bonded to each other through a predetermined gap, and then the liquid crystal forming the liquid crystal layer 23 Inject (drop) material into the gap. Then, the driver 28 and the flexible printed board 29 are mounted on the terminal pads by using an anisotropic conductive film at the non-facing portion 24 of the array substrate 21. As a result, the driver 28 and the flexible printed circuit board 29 are electrically connected to the pixels in the display area 27.

  Next, a spacer 30 is attached to the non-facing portion 24. At this time, the spacer 30 covers the connection portion 29a of the flexible printed circuit board 29 and absorbs the unevenness generated in the non-opposing portion 24 by sticking the driver 28 to the notch 30a so as to fit the non-opposing portion. The thickness difference between the liquid crystal display element 12 and the counter substrate 22 side is made substantially flat by suppressing the thickness difference between the liquid crystal display element 12 and the counter substrate 22 side. Through these steps, the liquid crystal display element 12 is completed.

  On the other hand, a lower transparent conductive film, an oxide film, an upper transparent conductive film, a protective film, etc. are appropriately formed on an insulating substrate, and an anisotropic conductive film is used to mount a flexible printed circuit board by thermocompression bonding. The touch panel 13 is completed.

  Then, UV curable resins having different viscosities are applied to the counter substrate 22 and the non-opposing portion 24 of the completed liquid crystal display element 12, respectively, and the completed touch panel 13 is aligned and stacked, and then irradiated with ultraviolet rays. As a result, the UV curable resin is cured to form the first bonding portion 33 and the second bonding portion 34. That is, the position of the liquid crystal display element 12 on the counter substrate 22 side is bonded to the touch panel 13 by the first bonding unit 33, and the position including the non-facing portion 24 of the liquid crystal display element 12 is bonded to the touch panel 13.

  Thereafter, the protective cover 15 is attached to the touch panel 13, and the display device 11 is completed.

  Then, a first bonding portion 33 that covers a part of the counter substrate 22 and bonds the counter substrate 22 to the touch panel 13 is formed of a translucent resin and covers the non-opposing portion 24 of the liquid crystal display element 12. The second bonding portion 34 for bonding the non-facing portion 24 to the touch panel 13 is formed of a translucent resin having a viscosity lower than that of the resin forming the first bonding portion 33. Therefore, the impact applied when the display device 11 is dropped or the like can be absorbed by the second bonding portion 34 more than the first bonding portion 33, and the non-opposing portion 24 (the driver 28 and the flexible printed circuit board 29) that is structurally weak. The connection portion 29a) can be reliably protected by the second bonding portion 34, and the mechanical strength can be improved.

  In addition, the first bonding portion 33 that bonds the flat counter substrate 22 side to the touch panel 13, and the second bonding portion 34 that bonds the non-opposing portion 24 side that tends to be uneven are bonded to the touch panel 13. The thickness of the resin tends to be different, and the difference in shrinkage due to the difference in the resin thickness tends to occur. Therefore, by making the viscosity of the resin forming the second bonding portion 34 smaller than the viscosity of the resin forming the first bonding portion 33, the first bonding portion 33 side and the second bonding portion 34 side are used. The difference in the shrinkage amount of the resin can be alleviated and the occurrence of tension (warpage) in the liquid crystal display element 12 can be suppressed, so that unevenness in the gap between the substrates 21 and 22 of the liquid crystal display element 12 can be suppressed. Unevenness of the display image in the display area 27 due to the unevenness of the gap can be suppressed.

  Furthermore, by sticking the spacer 30 to the non-opposing portion 24 and suppressing the thickness difference between the non-opposing portion 24 and the counter substrate 22 side, the flatness of the bonding surface by the bonding portion 14 is improved and the second The amount of resin used for the bonding portion 34 can be suppressed. Therefore, even when the display device 11 is thinned by dispersing the impact applied when the display device 11 is dropped, the mechanical strength can be further improved, and the resin is cured when the second bonding portion 34 is formed. The amount of shrinkage at the time can be reduced, and the difference in the amount of resin shrinkage at the position of the first bonding portion 33 and the second bonding portion 34 can be further suppressed, so that tension is applied to the liquid crystal display element 12. It is possible to more reliably suppress the occurrence of unevenness in the gap between the substrates 21 and 22 of the liquid crystal display element 12.

  In the above-described embodiment, the liquid crystal display element 12 may be a transmissive or transflective type that displays an image by dropping light from the back side, for example. In this case, the planar light source device (backlight) is arranged on the side opposite to the touch panel 13, that is, on the back side of the liquid crystal display element 12.

  The bonding unit 14 may include an appropriate bonding unit in addition to the first bonding unit 33 and the second bonding unit 34. That is, the bonding part 14 can be formed of at least two types of translucent resins having different viscosities.

  Although one embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

11 Display device
12 Liquid crystal display elements as display elements
13 Touch panel
14 Bonding part
21 Array substrate as one substrate
22 Counter substrate as the other substrate
24 Non-opposing part as peripheral part
27 Display area
28 Driver as a functional member
29 Flexible printed circuit boards as functional components
30 Spacer as thickness difference suppression member
33 First bonding part
34 Second bonding part

Claims (2)

A display device comprising: a display element; a touch panel that transmits the display by the display element; and a bonding unit that bonds the display element and the touch panel together.
The display element is
One substrate,
The other substrate which is disposed to face a part of the one substrate while maintaining a predetermined gap with respect to the one substrate, and forms a display area with the one substrate;
A peripheral portion provided with a functional member that is provided at a position not facing the other substrate of the one substrate and is electrically connected to the display region;
The bonding part is
A first bonding portion that is provided with a light-transmitting resin and is arranged to cover at least a part of the other substrate;
A second bonding portion that is provided with a light-transmitting resin having a viscosity lower than that of the resin that forms the first bonding portion, and is disposed so as to cover at least the peripheral portion of the display element. Display device. The display device according to claim 1, wherein the display element includes a thickness difference suppressing member that suppresses a thickness difference between the peripheral portion and the other substrate side.

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