JP2015031772A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can have an LCD panel and a backlight surely fixed with a narrower periphery of a display area and can suppress uneven display due to deformation of a sheet and allows improvement in appearance of an end part of the sheet.SOLUTION: An LCD panel 12 has a display area 26 in which images can be displayed in positions spaced from sides 12a and 12b on both sides and an end side 12c by prescribed lengths. A structure 15 has an outer edge extended outward beyond the LCD panel 12 and is arranged to cover the front side of the LCD panel 12. A fixing layer 49 fixes the rear side of the structure 15 to the front side of the LCD panel 12. An outer edge fixing layer 46 fixes the rear side of the structure 15 to a backlight holder 14 in the position of the outer edge. An eaves part 42 projects toward the display area 26 so as not to have a front end thereof located in the display area 26 in a position corresponding to the end side 12c of the LCD panel 12, in the backlight holder 14 and covers the end part of the backlight 13.

Description

  Embodiments described herein relate generally to a liquid crystal display device including a planar light source device that irradiates planar light on at least the back side of a display region of a liquid crystal display element.

  In recent years, smartphones have become widespread and terminal models have been differentiated. As a technique for differentiating such terminal models, introduction of a touch panel or enlargement of the screen is known.

  The introduction of the touch panel shifts the user interface from the conventional button method to the touch sensor method. In this case, generally, a structure such as a touch panel or a decorative board is attached to the display side of the LCD panel which is a liquid crystal display element. If there is a gap, that is, an air layer, between the structure and the LCD panel, the brightness, contrast and chromaticity of the LCD panel of the main body may be reduced due to the refractive index between the structure and the air layer. In addition to this, the thickness of the entire set increases, causing a reduction in size and thickness. In this regard, instead of an air layer between the structure and the LCD panel, connection holding resins and adhesive materials having substantially the same refractive index as glass or acrylic have been developed. Technology that integrates LCD panels with LCD panels has become widespread. As a manufacturing method, a method is generally employed in which the LCD panel and the structure are integrated, and then a backlight is attached to form a module.

  In addition, with regard to the large screen, it is possible to realize a large amount of information display by improving visibility and high definition, contributing to the improvement of convenience, and playing a part in the spread of smartphones and tablet PCs. However, in this case, if the terminal size is increased, it may be difficult to carry and poor operability, and the design may be impaired. In view of this, an increase in the terminal size is prevented by reducing the size of the display area of the LCD panel and reducing the peripheral area, that is, the frame portion, so-called narrow frame.

  On the other hand, when the LCD panel is narrowed, fixing the LCD panel and the backlight which is a planar light source device becomes a problem. In other words, in the case of a conventional wide-frame LCD panel, a substrate on the back side of the LCD panel, or a double-sided tape that is formed in a rectangular frame shape corresponding to the width of the frame portion and attached to the backlight, or Although the outer edge of the polarizing plate and the backlight are fixed, in the case of an LCD panel with a narrow frame, the frame part is narrow, so not only the processing limit of such double-sided tape occurs, but also the adhesive area of the double-sided tape There are also problems such as the fixed area of the reflective sheet of the backlight, the undulation in the reliability test of the optical sheet of the backlight, and the appearance of the edges of these optical sheets. Since the LCD panel is not self-luminous, it is essential to install a backlight. Therefore, a configuration that can securely fix the LCD panel and the backlight to each other is desired.

JP 2010-237493 A

  The problem to be solved by the present invention is that the liquid crystal display element and the planar light source device can be securely fixed while narrowing the periphery of the display area, display unevenness due to deformation of the optical sheet can be suppressed, and the optical sheet An object of the present invention is to provide a liquid crystal display device capable of improving the appearance of the end portion.

  The liquid crystal display device of the embodiment includes a liquid crystal display element, a planar light source device, a support frame, a structure, a fixed layer, an outer edge fixed layer, and a flange. The liquid crystal display element is formed in a rectangular shape having both sides and both sides. The liquid crystal display element includes a display area capable of displaying an image at a position separated by a predetermined distance from at least both sides and one end. The planar light source device irradiates at least the back side of the display area with planar light. This planar light source device includes a light guide and a plurality of optical sheets. The light guide is disposed opposite to the back side of the liquid crystal display element. The optical sheet is located on the liquid crystal display element side of the light guide. The support frame supports at least a part of the outer edge portion of the planar light source device. The structure is formed such that the outer edge extends outward from the outer edge of the liquid crystal display element, and is arranged to cover the display side of the liquid crystal display element. The fixing layer fixes the back side of the structure to the display side of the liquid crystal display element. The outer edge fixing layer fixes the back side of the structure to the support frame at the position of the outer edge. The collar portion protrudes toward the display region so that the tip portion is not located in the display region at a position corresponding to one end side of the liquid crystal display element on the support frame, and covers the end portion of the planar light source device. .

FIG. 2 is a cross-sectional view schematically showing an enlarged part of the liquid crystal display device according to one embodiment, where (a) shows a cross section and (b) shows a vertical section. It is a top view which shows a part of liquid crystal display device same as the above.

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

  1 and 2, reference numeral 11 denotes a liquid crystal display device. The liquid crystal display device 11 is used in various terminals such as a mobile phone, a smartphone, a portable game machine, a personal computer, a tablet PC, and a display device for in-vehicle navigation. It is used. The liquid crystal display device 11 includes an LCD panel 12 that is a liquid crystal display element, a backlight 13 that is a planar light source device disposed on the back side of the LCD panel 12, and a support frame that holds the backlight 13. The backlight holder 14 and the structure 15 arranged on the display side of the LCD panel 12 are arranged inside a housing frame, which is a set housing (not shown), and have a rectangular shape in plan view, for example. ing. In the following description, the display side (upper side in FIG. 1) of the LCD panel 12 is the front side, and the opposite side (lower side in FIG. 1) is the back side, that is, the rear side.

  The LCD panel 12 is a transmissive type that transmits planar light from the backlight 13 to display an image, or a transmissive part that transmits planar light from the backlight 13 and a reflective part that reflects incident light from the front side. And a transflective type with an active matrix type. This LCD panel 12 has (one and the other) long sides (one and the other) facing each other (one and the other) sides 12a, 12b and (one and the other) short sides facing each other (the one and the other). It has a quadrangular shape with outer edges defined by the end sides 12c and 12d. In this LCD panel 12, an array substrate 21 as a square substrate and a counter substrate 22 as a square substrate are arranged to face each other with a predetermined gap (cell gap) with the array substrate 21 in front. A liquid crystal layer 23 and a spacer (not shown) that holds a gap between the substrates 21 and 22 are interposed between the substrates 21 and 22 so that the substrates 21 and 22 are bonded to each other, and the front side of the array substrate 21 A polarizing plate 24 and a polarizing plate 25 are attached to the rear side of the counter substrate 22 and a plurality of pixels are arranged in a matrix to form an active area that can display an image, that is, a display region 26 in a square shape. Has been. A rectangular frame-shaped portion of the entire liquid crystal display device 11 located outside the display region 26 is a frame portion 27 that is a peripheral region.

  The array substrate 21 includes a glass substrate, a plurality of wiring portions formed in a grid pattern at positions corresponding to the display region 26 on the glass substrate, pixel electrodes that are formed on the glass substrate and constitute pixels in the display region 26, these It has a thin film transistor (TFT) which is a switching element for driving each pixel electrode. In addition, on the array substrate 21, a drive circuit 28 for driving each thin film transistor is mounted on an external terminal portion 29 extending from the counter substrate 22 toward the end 12d side. The drive circuit 28 may be directly mounted on, for example, a glass substrate, or the flexible printed circuit board (FPC) is electrically connected to the glass substrate while mounted on a separate flexible substrate. May be. The external terminal portion 29 is electrically connected to an external circuit via a flexible printed circuit board (not shown).

  The counter substrate 22 includes a glass substrate, a counter electrode that is a common electrode formed on the glass substrate, a color filter layer, and the like. The common electrode may be formed on the array substrate 21 side depending on the mode of the liquid crystal layer 23. The color filter layer may be formed on the array substrate 21 side.

  As the liquid crystal layer 23, for example, various modes such as a TN mode, an STN mode, a VA (MVA) mode, and an IPS mode can be used.

  The polarizing plates 24 and 25 are optical members formed in a sheet shape, and are arranged so as to selectively transmit or block a predetermined polarization component according to the mode of the liquid crystal layer 23.

  The display area 26 is arranged at a position spaced apart by a predetermined distance of, for example, 0.8 mm or less from the left and right sides 12a and 12b of the LCD panel 12 and the upper end 12c opposite to the external terminal portion 29. Yes.

  The backlight 13 includes a light source (not shown), a rectangular plate-shaped light guide plate 31 that is a light guide that converts light from the light source into planar light, and an optical sheet that is disposed on the front side of the light guide plate 31. As a diffusion sheet 33 and prism sheets 34 and 35 (one and the other), and a reflection sheet 36 disposed on the rear side of the light guide plate 31, and the planar light with respect to the rear side of the LCD panel 12 Irradiate.

  For example, a light emitting diode (LED) or the like is used as the light source, and is disposed to face one end of the light guide plate 31.

  The light guide plate 31 is disposed opposite to the rear side of the LCD panel 12. In this light guide plate 31, one end (the end surface located on the rear side of the external terminal portion 29 on the side 12d side of the LCD panel 12) facing the light source is an incident surface on which light is incident from this light source. The front main surface (one main surface) facing the rear side of the panel 12 is an emission surface 31a from which light is emitted, and a rear main surface (other main surface) opposite to the emission surface 31a. ) Is a refracting surface 31b on which light is reflected (refracted). The light guide plate 31 has an outer edge portion outward from the display region 26 and the outer edge portion of the LCD panel 12 so that at least a region corresponding to the entire display region 26 of the LCD panel 12 can be irradiated with planar light. As a result, the exit surface 31a (and the refracting surface 31b) has a larger area than the display area 26 and the LCD panel 12.

  The diffusion sheet 33 diffuses the light emitted from the light guide plate 31 to the front side, and covers the emission surface 31a of the light guide plate 31 and is directly superimposed on the emission surface 31a.

  The prism sheets 34 and 35 collect the light diffused by the diffusion sheet 33 and are sequentially stacked on the diffusion sheet 33.

  The reflection sheet 36 reflects a part of light leaking from the refracting surface 31b of the light guide plate 31 to the exit surface 31a, and is overlapped so as to cover the refracting surface 31b of the light guide plate 31.

  The diffusion sheet 33 and the prism sheets 34 and 35 are formed so that outer edge portions extend outward from the display region 26 of the LCD panel 12 and the end side 12c of the LCD panel 12, respectively. Further, the reflection sheet 36 is formed such that the outer edge extends to the outside from the display area 26 of the LCD panel 12 and the outer edges (both sides 12a, 12b and the end 12c) of the LCD panel 12. And a larger area than the LCD panel 12.

  The backlight holder 14 is also called a bezel, and supports the light source and the light guide plate 31 with a resin mold that is a support structure integrally formed of a rigid member such as a synthetic resin that does not transmit light. A holder main body part 41 as a support frame main body part and a flange part 42 projecting inward of the holder main body part 41 are provided.

  The holder body 41 corresponds to the sides 12a and 12b of the LCD panel 12, that is, the side walls 41a and 41b (one and the other) spaced apart substantially parallel to the sides 12a and 12b, and the LCD panel A rectangular frame is formed by end wall portions 41c and 41d corresponding to the twelve end sides 12c and 12d, that is, spaced apart substantially parallel to the end sides 12c and 12d (one and the other). The light guide plate 31 of the backlight 13 and the both sides of the sheets 33, 34, and 35 are arranged to face each other along the side walls 41a and 41b. In addition, the holder main body 41 is a rectangular frame-shaped facing portion 44 in which the front portions of the side wall portions 41a and 41b and both end wall portions are opposed to the rear side of the structure 15 at positions outside the LCD panel 12. Further, the rear portions of the side wall portions 41a and 41b and the both end wall portions serve as a rectangular frame-shaped support portion 45 facing the outer edge portion of the reflection sheet 36 of the backlight 13. Further, the structure 15 is fixed (attached) to and supported by the facing portion 44 via the outer edge fixing layer 46, and the outer edge of the reflection sheet 36 is supported by the support portion 45 via the support layer 47. Both sides of the part are fixed (pasted) and supported. Both sides of the support portion 45 protrude toward both sides of the light guide plate 31 and extend toward the display region 26 with respect to both sides 12a and 12b of the LCD panel 12.

  The outer edge fixing layer 46 is formed in a rectangular frame shape by, for example, an adhesive material or a buffer material, and elastically supports the structure 15 with respect to the holder main body 41 (backlight holder 14) at the position of the outer edge. It is like that. The outer edge fixing layer 46 is spaced outward from the LCD panel 12.

  The support layer 47 is, for example, a double-sided tape, and is formed linearly along the side of the support portion 45 of the holder main body 41, and has a width dimension of, for example, about 0.6 mm in the left-right width direction. The support layer 47 integrally fixes the backlight 13 to the backlight holder 14 (holder body 41).

  The collar portion 42 is inward (one of the LCD panels 12) from a position closer to the front side than the middle position in the front-rear direction of the end wall portion 41c of the holder main body portion 41 corresponding to the one side 12c of the LCD panel 12. Projecting vertically toward the end side 12c), the tip is spaced from one end 12c of the LCD panel 12. Therefore, the rear side of the flange part 42 is spaced forward from the support part 45 of the holder main body part 41, and the position of the rear side of the flange part 42 at the position of the inner rear part of the end wall part 41c. In addition, a notch-shaped space 48 is formed. In addition, an outer edge portion of one end of the light guide plate 31 and each of the sheets 33, 34, and 35 of the backlight 13 is fitted in the space portion 48, and the light guide plate 31 and each of the sheets 33 and 34 are provided by the flange portion 42. 35, the front side of the outer edge of one end of 35 is covered. Note that the sheets 33, 34, and 35, particularly the prism sheet 35 positioned at the forefront are not fixed (fixed) to the flange 42.

  The structure 15 is used for touch operation input based on a decorative plate that protects the LCD panel 12 so that the user does not directly touch the LCD panel 12, an image displayed on the display area 26 of the LCD panel 12, and the like. For example, a capacitive touch panel or a resistive touch panel is formed in a square plate shape. The structure 15 is formed in a region that covers at least the entire LCD panel 12 with a fixing layer 49 formed of a synthetic resin such as a translucent ultraviolet (UV) curable resin or an adhesive tape. It is fixed against. Further, the structure 15 has an outer edge portion of the LCD panel 12, that is, an outer edge portion extending outward from both sides 12a and 12b and both end sides 12c and 12d, and an outer edge portion outside the fixed layer 49. At the position, the outer edge fixing layer 46 is elastically bonded and fixed to the facing portion 44 of the backlight holder 14. In the outer edge portion of the structure 15, a light shielding portion 51 that blocks the light and forms the frame portion 27 is formed at a position facing the front sides of the both sides 12a and the end sides 12c of the LCD panel 12. Yes. The light shielding portion 51 is formed from the outer edge portion of the structure 15 over a predetermined width.

  The fixing layer 49 is a connection-holding resin, an adhesive, or the like, and bonds the LCD panel 12 and the structure 15 so as not to generate a gap in the front-rear direction, that is, without a gap. Therefore, no air layer is formed between the LCD panel 12 and the structure 15. For this reason, the LCD panel 12 is fixed to the structure 15 through the fixing layer 49, and the structure 15 is fixed to the backlight holder 14 (holder body 41) through the outer edge fixing layer 46. Therefore, the LCD panel 12 is indirectly fixed to the backlight holder 14 and the backlight 13 held by the backlight holder 14 via the structure 15. Further, the fixed layer 49 has a refractive index that is equal to or approximate to, for example, glass or acrylic. Therefore, the fixed layer 49 prevents the refractive index from changing between the front side of the LCD panel 12 (the polarizing plate 25 or the counter substrate 22) and the structure 15.

  The housing frame is made of, for example, synthetic resin or metal, is formed in a rectangular frame shape, and surrounds the outside of the LCD panel 12 in a frame shape.

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

  When assembling the liquid crystal display device 11, first, the LCD panel 12 and the structure 15 manufactured in advance are bonded together by the fixed layer 49.

  Further, the backlight 13 in which the diffusion sheet 33 and the prism sheets 34 and 35 are sequentially stacked on the light emission surface 31a of the light guide plate 31 and the reflection sheet 36 is stacked on the refractive surface 31b of the light guide plate 31 is provided as a backlight holder. 14 and attached to the support portion 45 of the backlight holder 14 by the support layer 47 at both side edges of the reflection sheet 36. In this state, the outer edge portion of one end of the light guide plate 31 and the sheets 33, 34, and 35 is fitted into the space portion 48 and covered with the flange portion 42.

  Then, the outer edge portion of the structure 15 that is integrally bonded to the LCD panel 12 is bonded to the backlight holder 14 via the outer edge fixing layer 46 to form a module. This module is accommodated in a housing frame, for example, and is appropriately connected to an external circuit to complete the liquid crystal display device 11.

  The completed liquid crystal display device 11 converts light from the light source into planar light by the light guide plate 31, and then transmits the planar light to the rear side of the LCD panel 12 via the diffusion sheet 33 and the prism sheets 34 and 35. Irradiate. In the LCD panel 12, the pixel is driven corresponding to the image to be displayed, the polarization direction of the planar light incident through the polarizing plate 25 is converted, and the amount of light transmitted through the polarizing plate 24 (transmission amount) is the pixel. By setting each time, the light passing through the structure 15 is visually recognized by the user as an image.

  Here, when so-called narrowing of the frame portion 27 of the liquid crystal display device 11 is performed, the LCD panel and the backlight are bonded to each other at the frame portion, and the reflection sheet of the backlight is attached to the backlight holder at the frame portion. In the conventional structure to be fixed, a sufficient adhesion area cannot be obtained. In addition, when the adhesion area (adhesion width) between the LCD panel and the backlight is increased, if the adhesion part extends to the end of the prism sheet that is located at the forefront, the end of the prism sheet is Swelling (deformation) occurs when the prism sheet is fixed under the predetermined reliability test and fixed to the backlight holder. Furthermore, in order to prevent such an undulation from interfering with the bonding position between the LCD panel and the backlight, the edge of the prism sheet is separated from the bonding position toward the display area side. This end portion approaches the outer edge portion of the display area, so that a so-called end appearance is seen from the user side. As described above, when the frame is narrowed with the conventional structure, it is possible to secure a bonding area for fixing the LCD panel 12, secure a fixing area for the reflective sheet 36, and sheets 33, 34, 35 (especially the prism sheet 35). ) In the reliability test, and various problems such as improvement in the appearance of the end portions of the light guide plate 31 and the sheets 33, 34, and 35 occur.

  Therefore, in the embodiment described above, the LCD panel 12 is not directly fixed to the backlight 13 (backlight holder 14), but is fixed to the LCD panel 12 through the fixing layer 49 as a single unit. The LCD panel 12 is indirectly fixed to the backlight 13 (backlight holder 14) by fixing the position of the outer edge to the backlight holder 14 (backlight 13) by the outer edge fixing layer 46. Therefore, a narrow frame LCD panel 12 having a display area 26 having an outer edge portion at a position separated by a predetermined distance of, for example, 0.8 mm or less from both sides 12a, 12b and one end side 12c. However, a bonding area for the backlight 13 can be secured by the structure 15 covering the LCD panel 12. That is, the outer edge portion of the structure 15 extends outward from both side edges 12a and 12b and both end edges 12c and 12d, which are outer edge portions of the LCD panel 12. Therefore, the backlight 13 (backlight holder) By arranging the outer edge fixing layer 46 to be fixed to 14), it is possible to effectively use the space and obtain a sufficient adhesion area (adhesion strength).

  In addition, the light guide plate 31 of the backlight 13 and the outer edge portion of one end of the sheets 33, 34, and 35 protrude from the backlight holder 14 toward the display region 26 so that the tip portion is not located in the display region 26. Therefore, these parts are not visually recognized from the user side, the edge appearance (irregular reflection) can be prevented and the appearance of the edges can be improved, and the seats 33, 34, and 35 can be prevented from falling off. Can be prevented by 42. That is, in the case of the liquid crystal display device 11 having a narrow frame portion 27, it is not easy to greatly extend the outer edge portion of the light guide plate 31 of the backlight 13 and one end of the sheets 33, 34, 35 to the outside of the display region 26. By providing the collar portion 42 on the backlight holder 14 and covering these portions, the outer edge portion of the light guide plate 31 of the backlight 13 and one end of the sheets 33, 34, and 35 are extended to the outside without unnecessarily extending. Visibility can be reliably prevented.

  Further, since the sheets 33, 34, 35, in particular, the prism sheet 35 positioned at the forefront are not directly fixed to the backlight holder 14 (the flange portion 42), the sheet 33 is subjected to a predetermined reliability test. , 34, 35 (especially the prism sheet 35) can be prevented from swelling (deformation), and display unevenness of the liquid crystal display device 11 due to this swell can be suppressed.

  Then, by fixing the reflection sheet 36 of the backlight 13 to the backlight holder 14 at positions corresponding to the both sides 12a and 12b of the LCD panel 12, the area of the support layer 47 for fixing the reflection sheet 36 is reduced. Even the framed liquid crystal display device 11 can be widely used, and the reflection sheet 36 can be more securely fixed to the backlight holder 14.

  As described above, the liquid crystal display device 11 secures an adhesive area for fixing the LCD panel 12 (adhesive area between the backlight 13 and the structure 15 by the outer edge fixing layer 46) while supporting a narrow frame. In addition, it is possible to secure a fixed region (area of the support layer 47) of the reflection sheet 36, to prevent the sheets 33, 34, and 35 (particularly, the prism sheet 35) from swelling under the reliability test, and to guide the light guide plate 31 and the sheet The appearance of the end portions of 33, 34, and 35 can be improved, and the product performance required for the liquid crystal display device can be surely satisfied.

  In the above embodiment, the optical sheet is not limited to the diffusion sheet 33 and the prism sheets 34 and 35, and the number of sheets is not limited to three as long as it is plural.

  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 Liquid crystal display
12 LCD panel as a liquid crystal display element
12a, 12b side
12c, 12d edge
13 Backlight, a planar light source device
14 Backlight holder as support frame
15 Structure
26 Display area
31 Light guide plate as light guide
33 Diffusion sheet as an optical sheet
34, 35 Prism sheet as optical sheet
36 Reflective sheet
42 Buttocks
46 Outer edge fixing layer
49 Fixed layer

Claims (2)

A liquid crystal display element having a display area that is formed in a quadrilateral shape having both sides and both sides, and that can display an image at a position separated from the both sides and one end by a predetermined distance;
A light guide disposed opposite to the back side of the liquid crystal display element, and a plurality of optical sheets positioned on the liquid crystal display element side of the light guide, and irradiates at least the back side of the display area with planar light A planar light source device,
A support frame that supports at least part of the outer edge of the planar light source device;
A structure in which an outer edge portion is formed to extend outward from an outer edge portion of the liquid crystal display element, and is disposed so as to cover the display side of the liquid crystal display element;
A fixing layer for fixing the back side of the structure to the display side of the liquid crystal display element;
An outer edge fixing layer for fixing the back side of the structure to the support frame at the position of the outer edge,
The tip of the planar light source device protrudes toward the display region so that the tip of the support frame does not lie in the display region at a position corresponding to one edge of the liquid crystal display element. A liquid crystal display device comprising: a covering collar portion. The liquid crystal display device according to claim 1, wherein the planar light source device includes a reflection sheet that is fixed to the back side of the support frame at positions corresponding to both sides of the liquid crystal display element.

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