JP2008216844A - Flat panel display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat panel display which can have a flexible board fixed surely, while securing thinness and reworkability. <P>SOLUTION: A first liquid coverlay 35 is provided to a foldback part 31 of the flexible board 4 to suppress repulsive force of the flexible board 4 due to a foldback of the foldback part 31 by the first coverlay 35. A second filmy coverlay 36 is provided to a fixation part 32 of the flexible board 4, where a portion of a both-sided tape 28 is fixed to secure fixing strength of a fixing member to the fixing part 32 of the flexible board 4. There is no need to make the both-sided tape 28 unnecessarily thick and increase the fixing strength; while the thickness constitution and reworkability are secured, the flexible board 4 can be fixed surely to a light guide plate 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flat display device including a flexible substrate that protrudes outward from a flat display element.

  Liquid crystal display devices, which are flat display devices, are widely used in the industrial field, and have been increasingly applied to portable terminal applications, taking advantage of their thinness and low power consumption.

  In recent years, with the spread of equipment equipped with a liquid crystal display device, there has been an increasing demand for miniaturization and thinning. There exists a flexible substrate as what implement | achieves this.

Such flexible substrates are mainly drawn out of the liquid crystal panel, which is a liquid crystal display element as a flat display element. However, due to the recent trend toward smaller and thinner products, The structure has been increasing in which the substrate is folded and fixed to the back side of the liquid crystal panel, for example, a light guide plate of a backlight, or a metal frame that covers the liquid crystal panel via a double-sided tape (for example, Patent Document 1).
JP 2001-133756 A

  However, the above-described flat display device has a problem that the liquid crystal panel is lifted or the attached flexible substrate is peeled off due to a strong repulsive force of the folded flexible substrate.

  Moreover, in order to avoid the problem, a strong double-sided tape is required, that is, a thick double-sided tape is required, resulting in problems such as preventing thinning and reducing reworkability.

  As a method of reducing the repulsive force of the flexible substrate, it is possible to use a liquid polyimide coverlay instead of the film-like polyimide coverlay of the flexible substrate. There is a problem that the compatibility with a certain acrylic pressure-sensitive adhesive is not good, and the flexible substrate itself cannot be fixed sufficiently.

  The present invention has been made in view of these points, and an object of the present invention is to provide a flat display device that can securely fix a flexible substrate while ensuring thinness and reworkability.

  The present invention relates to a flat display element, a structure at least partially located on one main surface side of the flat display element, and a base end side electrically connected to the flat display element, outward from the flat display element. A flexible substrate that protrudes, and the flexible substrate is folded to the one main surface side with respect to the flat display element, and is located on the leading end side of the folded portion, and the fixing substrate via the fixing member. A fixing portion fixed to a structure, a liquid first cover lay provided in the folded portion, and a film-like second cover lay provided in the fixing portion to which a part of the fixing member is fixed. It is equipped with.

  Then, a liquid first cover lay is provided at the folded portion of the flexible substrate, and a film-like second cover lay is provided at the fixing portion of the flexible substrate to which a part of the fixing member is fixed.

  According to the present invention, the repulsive force of the flexible substrate due to the folding of the folded portion is suppressed by the liquid first cover lay, and the fixing strength of the fixing member to the fixing portion of the flexible substrate is suppressed to the film-like second cover lay. Therefore, the fixing member can be made thicker than necessary to prevent the fixing strength from increasing, and the flexible substrate can be reliably fixed to the structure while ensuring the thinness and the reworkability.

  Hereinafter, the configuration of a flat display device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  In FIG. 1, reference numeral 1 denotes a transmissive liquid crystal display device as a flat display device. The liquid crystal display device 1 includes a liquid crystal display device (LCD) 2 that is a liquid crystal display element as a flat display element in a plan view. The liquid crystal panel 2 has a rectangular light guide plate 3 in plan view, which is a light guide as a structure disposed on the back side, which is one main surface of the liquid crystal panel 2, and a conductive thermoplastic adhesive (for example) AC) or the like, and a flexible substrate (FPC) 4 connected thereto.

  The liquid crystal panel 2 is, for example, of an active matrix type, and includes an array substrate (not shown) and a counter substrate disposed so as to face the array substrate. As shown in FIG. A liquid crystal layer C is interposed. Further, scanning lines 11 and signal lines 12 are formed in a lattice pattern on the array substrate, and thin film transistors (TFT) 13 as switching elements are arranged at the intersections of the scanning lines 11 and the signal lines 12, respectively. The areas surrounded by the scanning lines 11 and 11 and the signal lines 12 and 12 are the respective pixels 15. Therefore, the pixels 15 are formed in a matrix shape, and a portion where the pixels 15 are arranged is a quadrangular display area for displaying an image. At least a part of the circuit formed on the array substrate is electrically connected to a part of the circuit formed on the flexible substrate 4.

  The light guide plate 3 forms a part of a backlight which is a planar light source device that irradiates planar light on the back side of the liquid crystal panel 2, is formed in a quadrangular shape in plan view, and is formed on the back surface of the liquid crystal panel 2. One main surface side, which is the front surface facing each other, is fixed to the back surface of the liquid crystal panel 2 on the array substrate side by a double-sided tape 22 as a light guide fixing member.

  The flexible substrate 4 includes, for example, a flexible substrate body 25 on which a predetermined circuit for inputting a signal to the liquid crystal panel 2 is formed, and a cover lay portion 26 that protects the predetermined circuit of the flexible substrate body 25. And protrudes from one end of the liquid crystal panel 2.

  The flexible substrate main body 25 is formed in a thin film shape using, for example, a synthetic resin such as polyimide, and one end that is the base end side is connected to the liquid crystal panel 2 and the other end that is the front end side is connected to the liquid crystal panel 2. On the other hand, it has a free end shape, and the front end side of this free end shape is folded back to the back side which is one main surface so as to straddle the incident surface 3 a which is the side surface of the light guide plate 3. It is fixed to the back surface 3b by a double-sided tape 28 as a fixing member. Therefore, the flexible substrate body 25 is formed with a folded portion 31 that is curved in a substantially arc shape toward the liquid crystal panel 2 and a fixing portion 32 that is fixed by the double-sided tape 28. The flexible substrate body 25 is mounted with an LED or the like as a light source (not shown) at a position facing the incident surface 3a of the light guide plate 3 in a state of being folded back to the back side of the light guide plate 3. The light guide plate 3 constitutes the backlight.

  The cover lay part 26 is formed in a thin film shape, for example, than the flexible substrate body 25, and the inner surface side of the flexible substrate body 25 in the folded state extends from the vicinity of the proximal end side of the flexible substrate body 25 to the distal end side. Is formed. The cover lay portion 26 is provided with a liquid first cover lay 35 at a portion corresponding to the folded portion 31 of the flexible substrate body 25 and at a portion corresponding to the fixing portion 32 of the flexible substrate body 25. A film-like second cover lay 36 is provided.

  The first cover lay 35 is formed of, for example, liquid polyimide, and works in a vertical direction in FIG. 1 in which the repulsive force at the folded portion 31, that is, the folded flexible substrate body 25 tries to return due to elasticity. Repulsive force, in other words, a force to widen the gap between the flexible substrate body 25, the light guide plate 3 and the liquid crystal panel 2 (the light guide plate 3 and the liquid crystal panel 2 are pushed upward in the figure) Force).

  The second cover lay 36 is formed of polyimide, for example, and the double-sided tape 28 is fixed between the second cover lay 36 and the light guide plate 3.

  Next, the operation of the above embodiment will be described.

  When the liquid crystal display device 2 is assembled, for example, the flexible substrate 4 is attached to the light guide plate 3 in a state where the back side of the liquid crystal panel 2 to which the flexible substrate 4 is connected is bonded to the front surface of the light guide plate 3 by the double-sided tape 22. It is folded so as to straddle the incident surface 3a, and is fixed to the back surface 3b of the light guide plate 3 by the double-sided tape 28.

  At this time, the liquid first cover lay 35 is provided at the folded portion 31 of the flexible substrate 4, thereby suppressing the repulsive force of the flexible substrate 4 caused by folding of the folded portion 31 and fixing a part of the double-sided tape 28. By providing a film-like second cover lay 36 on the fixing portion 32 of the flexible substrate 4 to be used, a general adhesive material for the second cover lay 36 and the double-sided tape 28 to the fixing portion 32 of the flexible substrate 4 is used. The compatibility with a certain acrylic pressure-sensitive adhesive is better than the compatibility between the acrylic pressure-sensitive adhesive and liquid polyimide, and the fixing strength of the double-sided tape 28 to the flexible substrate 4 can be secured.

  As a result, the repulsive force of the flexible substrate 4 is reduced, and the double-sided tape 28 is thickened more than necessary, so that the fixing strength is not increased. Even if the fixing strength of the tape 28 is relatively small, a sufficient fixing force can be obtained, and the flexible substrate 4 can be securely fixed to the back surface 3b of the light guide plate 3, thus ensuring ease of reworking, that is, reworkability. In addition, the flexible substrate 4 can be securely fixed to the light guide plate 3.

  And since it can fix reliably, suppressing the repulsive force of the flexible substrate 4 in this way, the liquid crystal panel 2 does not float up by the repulsive force of the flexible substrate 4, or the flexible substrate 4 does not peel off, but a liquid crystal display The manufacturability of the device 1 can be improved.

  In each of the above embodiments, depending on the structure of the liquid crystal display device 1, the flexible substrate 4 may be fixed to, for example, a metal frame as a structure covering the liquid crystal panel 2 instead of the light guide plate 3. Even in this case, the same effects as those of the above-described embodiment can be obtained.

  Therefore, as the flat display device, other than the transmissive liquid crystal display device 1, for example, a reflective or transflective liquid crystal display device or the like can be used, and other than the liquid crystal display device, for example, an organic EL is used. The same can be applied to a flat display device or the like.

It is a longitudinal cross-sectional view which shows the flat display apparatus of one embodiment of this invention. It is a circuit diagram which shows a part of flat display apparatus same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device as a flat display device 2 Liquid crystal panel as a flat display element 3 Light guide plate which is a light guide as a structure 4 Flexible substrate
28 Double-sided tape as a fixing member
31 Folding part
32 Adhering part
35 First coverlay
36 Second coverlay

Claims (2)

A flat display element;
A structure in which at least a part is located on one main surface side of the flat display element;
The base end side is electrically connected to the flat display element, and comprises a flexible substrate protruding outward from the flat display element,
The flexible substrate is
A folded portion folded to the one main surface side with respect to the flat display element;
Located on the front end side of the folded portion, a fixing portion fixed to the structure via a fixing member,
A liquid first cover lay provided in the folded portion;
A flat display device, comprising: a film-like second cover lay provided at the fixing portion to which a part of the fixing member is fixed. The flat display device according to claim 1, wherein the structure is a light guide attached to one main surface side of the flat display element.

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