JP2014115313A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device that can suppress generation of display unevenness by suppressing contraction of a middle frame due to a temperature change, and minimizes generation of a display defect arising from a foreign substance generated by contact of the middle frame with a front frame.SOLUTION: The display device comprises: a display panel 2; a rear frame 10 that is disposed on a rear surface side of the display panel 2, and accommodates an optical member; and a backlight unit 3 that has a middle frame 5 anchored to the rear frame 10. The middle frame 5 includes: a display panel holding part 5a that holds an end of the display panel 2; and a cover part 5b that covers a side wall part 10b of the rear frame 10 located to be opposite the display panel holding part 5a from an outer side of the side wall part 10b.

Description

  The present invention relates to a flat panel display device, and more particularly to a structure that suppresses contraction of a middle frame due to a temperature change.

  In a conventional flat panel display device, a display panel such as a liquid crystal panel is positioned and held by a resin frame (middle frame) constituting a part of a backlight unit. By directly or indirectly fixing the resin frame and the front frame, the display panel is sandwiched between the resin frame and the front frame, and the vertical position on the display surface of the display panel is regulated. In addition, the display panel is held by the protrusions provided on the resin frame, so that the display panel is held in a normal position even when subjected to vibration and impact from a direction parallel to the display surface of the display panel. Yes.

  For example, in the display device described in Patent Document 1, a joint portion is provided between the middle frame and the rear frame to suppress movement between the two (first structure), or a joint portion is provided between the front frame and the middle frame. And a structure (second structure) that suppresses movement between the two.

JP 2008-158306 A (FIG. 11)

  In a middle frame made of a resin having a larger linear expansion coefficient than a glass display panel, the amount of expansion / contraction due to a temperature change from room temperature is large. Here, when the display device is used at a low temperature, the first structure described in Patent Document 1 is joined to the rear frame having a smaller linear expansion coefficient than that of the resin, so that the middle frame panel mounting surface Shrinkage on the opposite side is suppressed.

  However, since the shrinkage amount of the frame-shaped middle frame is larger than the shrinkage amount of the glass display panel on the side where the display panel is mounted in the middle frame, the middle frame shrinks and the middle frame display panel holding portion When the display panel is pressed and stress is generated in the display panel, an adverse effect on the display occurs.

  In addition, in the second structure described in Patent Document 1, a junction with a front frame having a smaller linear expansion coefficient than that of resin is provided in the vicinity of the panel mounting surface of the middle frame, so that the display panel holding unit also has a structure. Since the dimensional variation of the middle frame due to shrinkage at a low temperature is suppressed, adverse effects on the display can be avoided.

  However, by providing a joint between the resin middle frame and the metal front frame in the vicinity of the display panel, especially when vibration and impact due to external force occur, a part of the middle frame is scraped off by the front frame. There is a concern that the generated foreign matter may enter the display surface of the display panel and cause a display defect.

  Therefore, the present invention can suppress the occurrence of display unevenness by suppressing the contraction of the middle frame due to a temperature change, and the occurrence of display defects due to foreign matters caused by the contact of the middle frame with the front frame. An object of the present invention is to provide a display device with a small amount of noise.

  A display device according to the present invention includes a display panel, a rear frame that is disposed on the back side of the display panel and that houses an optical member, and a backlight unit that is fixed to the rear frame. The middle frame includes a display panel holding portion that holds an end portion of the display panel, and a cover portion that covers the side wall portion of the rear frame located on the opposite side of the display panel holding portion from the outside of the side wall portion. Is provided.

  According to the present invention, since the cover portion of the middle frame covers the side wall portion of the rear frame from the outside of the side wall portion, the movement of the middle frame is restricted by the rear frame even when the middle frame tends to contract due to temperature change. Thus, shrinkage of the display panel holding part of the middle frame can be suppressed. Thereby, since it can reduce that the display panel holding | maintenance part of a middle frame presses the edge part of a display panel, generation | occurrence | production of the stress in a display panel can be suppressed and generation | occurrence | production of a display nonuniformity can be suppressed by extension.

  In addition, since there is no need to provide a joint between the middle frame and the front frame in the vicinity of the display panel, the occurrence of display defects due to foreign matters caused by contact of the middle frame with the front frame is reduced.

It is a principal part perspective view of the backlight unit of the display apparatus which concerns on embodiment. It is a principal part back surface perspective view which shows the fixation structure of a rear frame and a middle frame. It is a principal part back surface perspective view of a middle frame. It is the sectional view on the AA line of FIG. FIG. 10 is a perspective view of main parts of a backlight unit of a display device according to modification example 1; It is a principal part back surface perspective view which shows the fixation structure of a rear frame and a middle frame. It is a principal part back surface perspective view of a middle frame. 14 is a perspective view of a main part of a backlight unit of a display device according to Modification 2. FIG. It is a principal part back surface perspective view which shows the fixation structure of a rear frame and a middle frame. It is a principal part back surface perspective view of a middle frame. It is a disassembled perspective view of a general display apparatus. It is a disassembled perspective view of the backlight unit of a general display apparatus. It is a principal part perspective view of the backlight unit of the display apparatus which concerns on a premise technique. It is the BB sectional view taken on the line of FIG. It is CC sectional view taken on the line of FIG.

<Prerequisite technology>
First, a display device as a premise will be briefly described with reference to FIGS. 11 is an exploded perspective view of a general display device, FIG. 12 is an exploded perspective view of a backlight unit 3 of the general display device, and FIG. 13 is a backlight of the display device according to the base technology. FIG. 14 is a cross-sectional view taken along line BB in FIG. 13, and FIG. 15 is a cross-sectional view taken along line CC in FIG. 13.

  As shown in FIG. 11, the display device includes a front frame 1, a display panel 2, a backlight unit 3, and a frame cover 4. The front frame 1 is formed in a frame shape by, for example, pressing a metal thin plate. A fixing claw (not shown) is formed on the side surface of the front frame 1.

  On the rear side of the front frame 1, a glass display panel 2 on which a control board 2 a is mounted for displaying an image, and a backlight serving as illumination for irradiating light from the opposite side of the display surface of the display panel 2. Unit 3 is arranged. The display panel 2 is attached to the backlight unit 3, and the frame cover 4 is attached to the back side of the control board 2a for the purpose of protecting the control board 2a mounted on the display panel 2.

  Next, the backlight unit 3 will be described. As shown in FIGS. 12 to 15, the backlight unit 3 includes a middle frame 5, an optical sheet 6, a light guide plate 7, a reflection sheet 8, an LED unit 9 having an LED 9 a as a light source, and a rear frame 10. And an insulating sheet 11. The middle frame 5 is formed in a frame shape from a resin material. A rear frame 10 is disposed on the back side of the middle frame 5. The rear frame 10 is formed of a metal material (for example, stainless steel, aluminum, iron, etc.), and includes a bottom plate portion 10a and a side wall portion 10b surrounding the bottom plate portion 10a.

  An optical sheet 6, a light guide plate 7, a reflection sheet 8, and an LED unit 9 are disposed between the middle frame 5 and the rear frame 10, and the optical sheet 6, the light guide plate 7, the reflection sheet 8, and the like. The LED unit 9 is sandwiched between the middle frame 5 and the rear frame 10. In order to guide the light output from the LED unit 9 to the display surface side of the display panel 2, the LED unit 9 is disposed on the side surface of the light guide plate 7. In the light guide plate 7, a light scattering portion (not shown) is formed on the surface opposite to the light exit surface (on the rear frame 10 side) to guide the light to the light exit surface by disturbing the light propagation direction. The light scattering portion functions as a means for extracting light from the light guide plate 7 by disturbing the total reflection condition of light propagating through the light guide plate 7.

  A reflection sheet 8 is disposed on the side opposite to the light exit surface of the light guide plate 7 in order to reflect light effectively. A plurality of optical sheets 6 for effectively using light are arranged on the light exit surface side (middle frame 5 side) of the light guide plate 7. The optical sheet 6 has a configuration in which two lens sheets (not shown) are sandwiched between a polarizing reflection sheet (not shown) and a diffusion sheet (not shown), but neither the polarizing reflection sheet nor the diffusion sheet is used. It is possible and can be optimized in view of required luminance, light distribution characteristics, and the like. In FIG. 13, the optical sheet 6, the light guide plate 7, the reflection sheet 8, and the LED unit 9 are omitted.

  Compared to the glass display panel 2, the resin middle frame 5 has a higher shrinkage due to temperature change. Therefore, when the middle frame 5 contracts, as shown in FIGS. 14 and 15, the display panel holding part 5a of the middle frame 5 holds a part of the peripheral edge of the display panel 2, but the display panel As the holding part 5a moves to the display panel 2 side, the end part of the display panel 2 is pressed. As a result, stress acts on the display panel 2 to cause deformation, resulting in display unevenness.

  Moreover, in order to suppress the shrinkage of the middle frame 5, there are many cases in which a resin containing glass fiber is employed for the middle frame 5, but the molding of the middle frame 5 is rapidly deteriorated by inserting the glass fiber. There is a problem that burrs are likely to occur in the middle frame 5 after molding. Hereinafter, an embodiment of the present invention that solves these problems will be described.

<Embodiment>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main part perspective view of a backlight unit 3 of a display device according to an embodiment of the present invention, and FIG. 2 is a main part rear perspective view showing a fixing structure of a rear frame 10 and a middle frame 5. 3 is a rear perspective view of the main part of the middle frame 5, and FIG. 4 is a cross-sectional view taken along line AA of FIG.

  The display device according to the embodiment of the present invention includes a front frame 1, a display panel 2, a backlight unit 3, and a frame cover 4, similarly to the configuration of the general display device described above. The backlight unit 3 includes a middle frame 5, an optical sheet 6, a light guide plate 7, a reflection sheet 8, an LED unit 9 that is a light source, a rear frame 10, and an insulating sheet 11. The optical sheet 6, the light guide plate 7, the reflection sheet 8, and the LED unit 9 correspond to optical members, and the optical members are omitted in FIG.

  In the display device according to the embodiment of the present invention, the fixing structure of the rear frame 10 and the middle frame 5 in the backlight unit 3 is different from the presupposed technology. Therefore, a fixing structure between the rear frame 10 and the middle frame 5 will be described. In the embodiment, the same components as those described in the base technology are denoted by the same reference numerals, and description thereof is omitted.

  A circular hole 10c is formed in the peripheral region of the corner of the bottom plate portion 10a of the rear frame 10. A concave surface 10e that is recessed toward the display panel 2 is formed in a region corresponding to the hole 10c in the side wall portion 10b of the rear frame 10, and an engagement hole 10d is formed in the concave surface 10e.

  The middle frame 5 includes a display panel holding part 5a, a cover part 5b, a recessed part 5e, and a protruding part 5f. The display panel holding portion 5a is formed so as to protrude from the peripheral region of the corner portion of the middle frame 5 to the display panel 2 side, and more specifically, the end portion of the display panel 2 (more specifically, the corner at the peripheral portion of the display panel 2). The display area side of the display device is held in the peripheral area) and the optical sheet 6.

  The cover portion 5b is formed on the opposite side of the display panel holding portion 5a (more specifically, from the peripheral region of the corner portion of the middle frame 5 to the opposite side to the display panel 2), and the corner of the rear frame 10 at the side wall portion 10b. This is for covering the concave surface 10e, which is the peripheral region of the part, from the outside of the concave surface 10e. An engagement claw 5c that engages with the engagement hole 10d is formed at a position corresponding to the engagement hole 10d of the side wall 10b of the rear frame 10 on the inner surface of the cover portion 5b.

  The recess 5e is formed in the peripheral region of the corner portion on the back side of the middle frame 5, and a columnar projection 5f protruding toward the rear frame 10 is provided in the recess 5e. The protrusion 5f is engaged with the hole 10c of the bottom plate 10a of the rear frame 10.

  As described above, in the state where the middle frame 5 is fixed to the rear frame 10, the engagement claw 5c of the cover portion 5b is engaged with the engagement hole 10d of the concave surface 10e, and the inner surface of the cover portion 5b contacts the concave surface 10e. doing. Thereby, even when the middle frame 5 contracts due to a temperature change, the movement to the display panel 2 side is restricted by the metal rear frame 10 having a predetermined rigidity and a small linear expansion coefficient, and the display panel holding portion 5a is Since the action of pressing the end portion of the display panel 2 can be reduced, the occurrence of display unevenness can be suppressed. Here, as for the width of the cover portion 5b of the middle frame 5, the end portion of the cover portion 5b has the same width as the end portion of the display panel holding portion 5a, so that the middle frame 5 can be more effectively prevented from contracting. To do.

  In the second structure described in Patent Document 1, when the display device is assembled, a part of the middle frame is shaved due to interference between the connection portions of the middle frame and the front frame when vibration and impact from external force are applied. As a result, foreign matter is generated, and there is a concern that the generated foreign matter may enter the display surface of the display panel. However, as shown in FIG. 4, in the structure of the display device according to the embodiment, the front frame 1 covers the middle frame 5 from the display surface side of the display device. Foreign objects can be prevented from entering the display device.

  Further, on the back side of the backlight unit 3, the projection 5f is inserted and fixed (engaged) in the hole 10c, so that the display panel of the display panel holding unit 5a can be used even when the middle frame 5 contracts due to a temperature change. Movement to the second side is restricted. Thereby, even when the linear expansion coefficients of the optical sheet 6, the light guide plate 7, the reflection sheet 8, and the like are smaller than the linear expansion coefficient of the middle frame 5, the middle sheet 5 to the optical sheet 6, the light guide plate 7, and the reflection sheet 8. And no extra stress is applied.

  When assembling the display device, when the protrusion 5f is inserted and fixed in the hole 10c, the protrusion 5f is formed of resin, so that the protrusion 5f is easily cut off, and the protrusion 5f is scraped off to generate foreign matter. However, since the foreign substance is accommodated in the recess 5e, it is possible to prevent the foreign substance from entering the backlight unit 3. In addition to the assembly of the display device, foreign matter may be generated even in a use environment where vibration and impact are applied. However, as in the case described above, the effect of preventing foreign matter from entering the backlight unit 3 can be obtained.

  As shown in FIG. 1, the outer surface of the cover portion 5 b of the middle frame 5 and the outer surface of the side wall portion 10 b of the rear frame 10 coincide with each other. The cover portion 5b of the middle frame 5 covers the concave surface 10e of the rear frame 10, and the thickness of the cover portion 5b of the middle frame 5 is reduced by denting the concave surface 10e inward from the side wall portion 10b of the rear frame 10. By absorbing, the outer surface of the cover portion 5b of the middle frame 5 and the outer surface of the side wall portion 10b of the rear frame 10 can be matched. The reason for making the outer surfaces of the cover portion 5b and the side wall portion 10b coincide is to reduce the frame size from the display area of the display device to the outer edge of the display device. Thereby, it becomes possible to deal with a display device with a narrow frame. That is, the display device can be downsized.

  As described above, in the display device according to the embodiment, the cover portion 5b of the middle frame 5 covers the concave surface 10e of the side wall portion 10b of the rear frame 10 from the outside of the concave surface 10e. Even when trying to do so, the movement of the middle frame 5 is restricted by the rear frame 10, and the contraction of the display panel holding part 5a of the middle frame 5 can be suppressed. Thereby, since it can reduce that the display panel holding | maintenance part 5a of the middle frame 5 presses the edge part of the display panel 2, generation | occurrence | production of the stress in the display panel 2 can be suppressed, and also generation | occurrence | production of a display nonuniformity is suppressed. be able to.

  Further, since there is no need to provide a joint between the middle frame 5 and the front frame 1 in the vicinity of the display panel 2, the occurrence of display defects due to foreign matters caused by contact of the middle frame 5 with the front frame 1 is reduced.

  Since the engagement hole 10d is formed in the concave surface 10e of the side wall part 10b of the rear frame 10, and the engagement claw 5c that engages with the engagement hole 10d is formed in the cover part 5b of the middle frame 5, the rear frame 10 and the middle The frame 5 is fixed more firmly, and the movement of the middle frame 5 is further restricted by the rear frame 10. Thereby, since it can further reduce that the display panel holding | maintenance part 5a of the middle frame 5 presses the edge part of the display panel 2, generation | occurrence | production of a display nonuniformity is suppressed further.

  On the opposite side of the display surface of the display device, the middle frame 5 is formed with a cylindrical projection 5f, and the rear frame 10 is formed with a hole 10c for engaging the projection 5f. The frame 5 is fixed more firmly, and the movement of the middle frame 5 is further restricted by the rear frame 10. Thereby, since it can further reduce that the display panel holding | maintenance part 5a of the middle frame 5 presses the edge part of the display panel 2, generation | occurrence | production of a display nonuniformity is suppressed further.

  Since the protrusion 5f is formed in the recess 5e provided in the middle frame 5, it is possible to prevent foreign matter generated by the protrusion 5f from being cut into the backlight unit 3. Thereby, contraction of the middle frame 5 due to temperature change can be suppressed, and occurrence of display unevenness can be suppressed.

  Further, it is not necessary to put glass fibers for suppressing expansion and contraction due to temperature changes in the middle frame 5, and effects such as extending the life of the molding die and suppressing the occurrence of burrs in the middle frame 5 can be obtained. Thereby, the yield of the display device can be improved. In the above embodiment, the structure for fixing the rear frame 10 and the middle frame 5 in the backlight unit 3 is provided in the peripheral region of the corner of the backlight unit 3, but the present invention is not limited to this. The position and the number of the fixing structures can be arbitrarily determined.

<Modification 1>
The shape of the protrusion is not limited to a cylindrical shape, and may be another shape. For example, as shown in FIGS. 5 to 7, the protrusion may be formed in an oval shape when viewed from the back side of the middle frame 5. FIG. 5 is a main part perspective view of the backlight unit 3 of the display device according to the modification 1. FIG. 6 is a main part rear perspective view showing a fixing structure between the rear frame 10 and the middle frame 5. 7 is a rear perspective view of the main part of the middle frame 5.

  In the first modification, a protrusion 5g is formed on the rear frame 10 side of the middle frame 5, and the protrusion 5g is formed in an oval shape when viewed from the back side of the middle frame 5 (opposite to the display surface of the display device). Has been. The bottom plate portion 10a of the rear frame 10 is formed with an oblong hole portion 10f into which the protruding portion 5g can be engaged.

  As described above, the elongated frame-shaped protrusion 5g is formed on the middle frame 5 as viewed from the back side of the middle frame 5, and therefore, compared with the case of the first embodiment, the protrusion 5g and the hole 10f The contact area increases. As a result, the strength for preventing the protrusion 5g from breaking can be increased, and the rear frame 10 and the middle frame 5 are more firmly fixed, and the rear frame 10 further restricts the movement of the middle frame 5. The

<Modification 2>
For example, as shown in FIGS. 8 to 10, the protrusion may be formed in an L shape when viewed from the back side of the middle frame 5. FIG. 8 is a perspective view of main parts of the backlight unit 3 of the display device according to the second modification, and FIG. 9 is a rear perspective view of main parts showing a fixing structure between the rear frame 10 and the middle frame 5. 10 is a rear perspective view of the main part of the middle frame 5.

  In the second modification, a protrusion 5h is formed on the rear frame 10 side of the middle frame 5, and the protrusion 5h is formed in an L shape when viewed from the back side of the middle frame 5 (opposite to the display surface of the display device). Has been. The bottom plate portion 10a of the rear frame 10 is formed with an L-shaped hole 10g with which the protrusion 5h can be engaged.

  As described above, since the middle frame 5 is formed with the L-shaped projection 5h when viewed from the back side of the middle frame 5, the projection 5h and the hole 10g are compared with the case of the first embodiment. The contact area increases. As a result, the strength for preventing the protrusion 5h from breaking can be increased, and the rear frame 10 and the middle frame 5 are more firmly fixed, and the rear frame 10 further restricts the movement of the middle frame 5. The

  In the present invention, the embodiments can be appropriately modified and omitted within the scope of the invention.

  2 Display panel, 3 Backlight unit, 5 Middle frame, 5a Display panel holding part, 5b Cover part, 5c Engaging claw, 5e Recessed part, 5f, 5g, 5h Projection part, 6 Optical sheet, 7 Light guide plate, 8 Reflecting sheet 9 LED unit, 10 rear frame, 10c, 10f, 10g hole, 10d engagement hole, 10e concave surface.

Claims (5)

A display panel;
A backlight unit disposed on the back side of the display panel and having an optical member and a middle frame fixed to the rear frame;
With
The middle frame includes a display panel holding portion that holds an end portion of the display panel, and a cover portion that covers the side wall portion of the rear frame located on the opposite side of the display panel holding portion from the outside of the side wall portion. , Display device. An engagement hole is formed in the side wall portion of the rear frame,
The display device according to claim 1, wherein an engagement claw that engages with the engagement hole is formed in the cover portion of the middle frame. On the opposite side of the display surface of the display device, a projection is formed on the middle frame,
The display device according to claim 1, wherein a hole portion with which the protrusion is engaged is formed in the rear frame.   The display device according to claim 3, wherein the protrusion is formed in a recess provided in the middle frame.   5. The display device according to claim 3, wherein the protrusion is formed in a cylindrical shape, an oval shape or an L shape when viewed from the opposite side of the display surface of the display device.

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