JP2014182165A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat dissipation without adding components.SOLUTION: A back light 12 comprises a long flexible wiring board 26 on which a plurality of light emitting components 22 are mounted and whose first side end 30 and second side end 32 located at both ends in the direction of the width thereof extend in the direction of the length thereof. A plurality of light emitting components 22 are arranged on the flexible wiring substrate 26 so as to be lined up in the direction of the length thereof, displaced toward the second side end 32 in the width direction thereof, with light emitting faces 24 facing toward the first side end 30. The flexible wiring substrate 26 is a multi-layer substrate and has wiring patterns 36 in two or more layers. The wiring patterns 36 in the layers include the wiring pattern 36H in the uppermost layer jointed to the plurality of light emitting components 22. The wiring pattern 36H in the uppermost layer is pulled out in the direction of the length of the flexible wiring substrate 26 from an area overlapping the corresponding light emitting component 22, and also has a portion pulled out further forward than the corresponding light emitting face 24, on the first side end 30 side.

Description

  The present invention relates to a liquid crystal display device.

  In a liquid crystal display device having a sidelight type backlight, a plurality of light emitting diodes are concentrated and mounted on a flexible wiring board in order to make the product compact. For this reason, there is a region where heat of the light emitting diode is concentrated, and the optical sheet is swelled by the heat, and the screen quality may be deteriorated.

  Since a liquid crystal display device for portable use such as a smartphone is further required to have high definition and outdoor visibility after adding a touch panel, further increase in brightness of the backlight is required. For this reason, it is necessary to increase the number of light emitting diodes, and it is necessary to house them in a narrow casing. Therefore, the arrangement of the light emitting diodes becomes dense, and the amount of heat generation must be increased.

Japanese Patent No. 4389921 JP 2010-44116 A

  Japanese Patent Application Laid-Open No. H10-260260 discloses dissipating heat by providing a heat dissipating terminal that is electrically non-conductive with a light emitting element. Patent Document 2 discloses that a side surface portion of a liquid crystal display panel and FPC (Flexible Printed Circuits) are connected by a soft heat conductive adhesive. However, since these parts are added for heat dissipation, the cost increases.

  An object of this invention is to improve heat dissipation, without adding components.

  (1) A liquid crystal display device according to the present invention includes a liquid crystal display panel and a sidelight type backlight, and the backlight includes a plurality of light emitting components each having a light emitting surface, and the plurality of light emitting elements. And a long flexible wiring board having a first side end and a second side end at both ends in the width direction and extending in the length direction. The plurality of light emitting components are attached to the flexible wiring board. The flexible wiring board is arranged in a line in the length direction, is shifted to the second side end side in the width direction, and is arranged with the light emitting surface facing the first side end side. A multilayer substrate having a plurality of wiring patterns, wherein the plurality of wiring patterns include an uppermost wiring pattern bonded to the plurality of light emitting components, and the uppermost wiring patterns are respectively Of the light emitting parts From the region, it said flexible wiring board is pulled out in the longitudinal direction, and having a further portion drawn forward from the light emitting surface on the side of the first side edge. According to the present invention, since the uppermost wiring pattern extends in the direction in which the light emitting surface that easily generates heat faces, the heat dissipation can be improved without adding components.

  (2) In the liquid crystal display device described in (1), the flexible wiring board is in the same layer as the uppermost wiring pattern, but in a separated state, each light emitting component has the first side end. The metal layer may be arranged so as to be adjacent to each other, and the metal layer may be electrically insulated from the plurality of light emitting components.

  (3) In the liquid crystal display device described in (1) or (2), the flexible wiring board includes an insulating layer that covers the wiring pattern of the uppermost layer, and the insulating layer includes the plurality of light emitting components. It may be characterized by having a plurality of openings for electrical connection.

  (4) In the liquid crystal display device described in any one of (1) to (3), the flexible wiring board has a connector at an end in the length direction, and the connector includes the plurality of layers. The wiring pattern may be electrically connected to the plurality of light emitting components.

  (5) In the liquid crystal display device described in (4), the plurality of light emitting components are divided into a plurality of groups, each of the groups includes the same number of the light emitting components, and the wiring patterns of the plurality of layers are The light-emitting components belonging to each one of the groups may be connected in parallel, and the light-emitting components in the same order of arrangement in different groups may be connected in series.

  (6) In the liquid crystal display device according to (5), the plurality of layers of wiring patterns include connection wiring extending in the length direction of the flexible wiring board, and at least one other than the wiring pattern of the uppermost layer. The wiring pattern of the layer may include at least a part of the connection wiring.

  (7) In the liquid crystal display device described in (6), the wiring pattern in the uppermost layer includes a part of the connection wiring, and the part of the connection wiring included in the wiring pattern in the uppermost layer. May pass through a region adjacent to the light emitting component of the group closest to the connector on the first side end side.

  (8) In the liquid crystal display device described in (7), the part of the connection wiring included in the wiring pattern in the uppermost layer may include the group other than the group closest to the connector. The light-emitting component may pass through a region adjacent to the first side end on the first side end side.

It is a top view which shows the backlight of the liquid crystal display device which concerns on embodiment of this invention. It is an expanded sectional view along the II-II line of the backlight shown in FIG. It is a top view of a flexible wiring board. It is an enlarged view which shows the uppermost layer of the part shown by IV of the flexible wiring board shown in FIG. It is a figure which shows the lower layer of the part shown by IV of the flexible wiring board shown in FIG. It is an enlarged view which shows the uppermost layer of the part shown by V of the flexible wiring board shown in FIG. It is a figure which shows the lower layer of the part shown by V of the flexible wiring board shown in FIG. It is a circuit diagram of the uppermost wiring pattern. It is a circuit diagram of a lower layer wiring pattern. It is a circuit diagram of the whole wiring pattern of multiple layers.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a plan view showing a backlight of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view taken along line II-II of the backlight shown in FIG.

  The liquid crystal display device has a liquid crystal display panel 10 as indicated by phantom lines in FIG. The backlight 12 illuminates the liquid crystal display panel 10 from the back. The backlight 12 includes a light guide plate 14. The surface of the light guide plate 14 faces the back surface of the liquid crystal display panel 10. An optical sheet 16 is disposed between the liquid crystal display panel 10 and the light guide plate 14. The optical sheet 16 includes a diffusion sheet and a prism sheet. A reflection sheet 18 is disposed under the light guide plate 14 (on the side opposite to the optical sheet 16). The backlight 12 includes a metal frame 20, for example. The frame 20 houses the light guide plate 14 inside.

  The backlight 12 includes a plurality of light emitting components 22. The light emitting component 22 is, for example, a light emitting diode. The light emitting component 22 is a point light source for introducing light into the light guide plate 14. Light from the point light source is converted into a surface light source by the light guide plate 14 and irradiated onto the liquid crystal display panel 10. The light emitting component 22 has a light emitting surface 24, and the light emitting surface 24 faces the end surface of the light guide plate 14. The backlight 12 is a sidelight system.

  The backlight 12 includes a flexible wiring board 26. The light emitting component 22 is mounted on the flexible wiring board 26, and heat of the light emitting component 22 is transmitted to the flexible wiring board 26. In order to dissipate the heat, a heat radiating material 28 is provided outside the flexible wiring board 26.

  FIG. 3 is a plan view of the flexible wiring board 26. The flexible wiring board 26 has a long shape, and the first side end 30 and the second side end 32 at both ends in the width direction extend in the length direction. The flexible wiring board 26 has a connector 34 at an end in the length direction. The flexible wiring board 26 is a multilayer board.

  4A is an enlarged view showing the uppermost layer of the portion indicated by IV of the flexible wiring board 26 shown in FIG. 4B is a diagram showing a lower layer of a portion indicated by IV of the flexible wiring board 26 shown in FIG.

  FIG. 5A is an enlarged view showing the uppermost layer of the portion indicated by V of the flexible wiring board 26 shown in FIG. FIG. 5B is a diagram illustrating a lower layer of a portion indicated by V of the flexible wiring board 26 illustrated in FIG. 3.

  The flexible wiring board 26 includes a plurality of wiring patterns 36. In this embodiment, the multi-layer wiring pattern 36 is the uppermost wiring pattern 36H shown in FIGS. 4A and 5A and the lower wiring pattern 36L shown in FIGS. 4B and 5B, both of which are formed on both sides of the substrate. Has been. The uppermost wiring pattern 36H and the lower wiring pattern 36L are electrically connected through a through hole 38. The connector 34 is electrically connected to a plurality of layers of wiring patterns 36.

  The uppermost wiring pattern 36 </ b> H has a plurality of joint portions 40 (terminals) for electrical joining with the plurality of light emitting components 42. The uppermost wiring pattern 36 </ b> H is covered with an insulating layer 42. The insulating layer 42 has a plurality of openings 44 for exposing the plurality of joints 40. The uppermost wiring pattern 36H is drawn from the joint portion 40 in the length direction of the flexible wiring board 26 (left and right in FIGS. 4A and 5A), and further on the first side end 30 side (in FIGS. 4A and 5A). Pulled upward).

  The flexible wiring board 26 has a metal layer 46. The metal layer 46 is in the same layer as the uppermost wiring pattern 36H but is separated. The metal layer 46 is disposed adjacent to the joint 40 on the first side end 30 side.

  As shown in FIGS. 4B and 5B, the multi-layer wiring pattern 36 includes connection wirings 48 extending in the length direction of the flexible wiring board 26. Specifically, at least one wiring pattern 36L other than the uppermost layer has a connection wiring 48L. Further, as shown in FIG. 5B, the uppermost wiring pattern 36 </ b> H also has connection wiring 48 </ b> H extending in the length direction of the flexible wiring board 26.

  As shown in phantom lines in FIGS. 4A and 5A, a plurality of light emitting components 22 are mounted on the flexible wiring board 26. The plurality of light emitting components 22 are arranged in a line in the length direction of the flexible wiring board 26. The plurality of light emitting components 22 are displaced from the second side end 32 in the width direction of the flexible wiring board 26. The plurality of light emitting components 22 are arranged with the light emitting surface 24 facing the first side end 30 side of the flexible wiring board 26.

  The plurality of light emitting components 22 are bonded to the plurality of bonding portions 40 of the uppermost wiring pattern 36H. The joint 40 and the light emitting component 22 are electrically connected through the opening 44 formed in the insulating layer 42. One light emitting component 22 has a pair of electrodes (not shown), and one electrode is joined to one joint 40. The plurality of light emitting components 22 are electrically connected to the connector 34 by a plurality of wiring patterns 36.

  FIG. 6 is a circuit diagram of the uppermost wiring pattern 36H. FIG. 7 is a circuit diagram of the lower wiring pattern 36L. Since the uppermost wiring pattern 36 </ b> H and the lower wiring pattern 36 </ b> L are connected through the through hole 38, a circuit is configured by the entire wiring pattern 36 of the plurality of layers.

FIG. 8 is a circuit diagram of the entire multi-layer wiring pattern 36. The plurality of light emitting components 22 mounted on the flexible wiring board 26 are divided into a plurality of groups G _{1 to} G ₅ . In the arrangement shown in FIG. 6, the plurality of light emitting components 22 are divided into a plurality of groups G _{1 to} G ₅ for each of the same number (six) in order from the leftmost light emitting component 22. Each of the groups G _{1 to} G ₅ includes the same number (six) of light emitting components 22.

As shown in FIG. 8, the light emitting components 22 belonging to the same group G _{1 to} G ₅ (any one) are connected in parallel. As shown in FIGS. 6 and 7, the parallel connection is achieved by the uppermost wiring pattern 36 </ b> H and the lower wiring pattern 36 </ b> L connected by the through hole 38.

As shown in FIG. 8, the light emitting components 22 in the same order of arrangement in different groups G _{1 to} G ₅ (plural) are connected in series. For example, in each of the different groups G _{1 to} G ₅ shown in FIG. 6, the leftmost light-emitting components 22 _{G 1 to} 22 _{G 5} (five) are the uppermost wiring pattern 36 H connected by the through hole 38 and the lower layer wiring pattern 36 H. The wiring patterns 36L are connected in series.

As can be seen with reference to FIG. 6, FIG. 4A in which the portion indicated by IV in FIG. 3 is enlarged shows the light-emitting component 22 of the group G ₁ farthest from the connector 34, and the portion indicated by V in FIG. the enlarged view 5A, the light emitting part 22 nearest group G ₅ to the connector 34 is shown.

As shown in FIG. 5A, the connection wiring 48H included in the uppermost layer of the wiring pattern 36H is a light emitting part 22 nearest group G ₅ to the connector 34, passing through the area adjacent the side of the first side edge 30. The connection wiring 48H included in the uppermost wiring pattern 36H is not formed in the region shown in FIG. 4A. That is, the connection wiring 48 </ b> H included in the uppermost wiring pattern 36 </ b> H is adjacent to the light emitting components 22 of the remaining groups G _{1 to} G ₄ excluding the group G ₅ closest to the connector 34 on the first side end 30 side. The area does not pass.

  The uppermost wiring pattern 36H is drawn out in the length direction of the flexible wiring board 26 (left-right direction in FIGS. 4A and 5A) from the region overlapping with each light emitting component 22, and further emits light toward the first side end 30. It has a portion drawn forward from the surface 24.

  According to the present embodiment, since the uppermost wiring pattern 36H extends in the direction in which the light emitting surface 24 that easily generates heat faces, the heat dissipation can be improved without adding components. The metal layer 46 is disposed adjacent to each light emitting component 22 on the first side end 30 side. The metal layer 46 also contributes to improving heat dissipation. The metal layer 46 is electrically insulated from the plurality of light emitting components 22.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the configuration described in the embodiment can be replaced with substantially the same configuration, a configuration that exhibits the same operational effects, or a configuration that can achieve the same purpose.

  DESCRIPTION OF SYMBOLS 10 Liquid crystal display panel, 12 Backlight, 14 Light guide plate, 16 Optical sheet, 18 Reflective sheet, 20 Frame, 22 Light emitting component, 24 Light emitting surface, 26 Flexible wiring board, 28 Heat radiation material, 30 1st side edge, 32 2nd Side end, 34 connector, 36 Multiple layer wiring pattern, 36H Top layer wiring pattern, 36L Lower layer wiring pattern, 38 Through hole, 40 Junction, 42 Insulating layer, 44 Opening, 46 Metal layer, 48 Connection wiring, 48H Connection wiring, 48L connection wiring.

Claims (8)

A liquid crystal display panel;
Sidelight type backlight,
Have
The backlight includes a plurality of light emitting components each having a light emitting surface, and a long shape in which the plurality of light emitting components are mounted and first and second side ends at both ends in the width direction extend in the length direction. A flexible wiring board, and
The plurality of light emitting components are arranged in a line in the length direction on the flexible wiring board, are shifted to the second side end side in the width direction, and the light emission is on the first side end side. Placed face up,
The flexible wiring board is a multilayer board, and has a plurality of layers of wiring patterns,
The plurality of layers of wiring patterns include an uppermost layer wiring pattern bonded to the plurality of light emitting components,
The uppermost wiring pattern is drawn out in the length direction of the flexible wiring board from a region overlapping with each of the light emitting components, and is further drawn forward from the light emitting surface to the first side end side. A liquid crystal display device comprising: The liquid crystal display device according to claim 1,
The flexible wiring board includes a metal layer arranged to be adjacent to each light emitting component on the first side end side in the same layer as the uppermost wiring pattern but separated.
The liquid crystal display device, wherein the metal layer is electrically insulated from the plurality of light emitting components. The liquid crystal display device according to claim 1 or 2,
The flexible wiring board has an insulating layer covering the uppermost wiring pattern,
The liquid crystal display device, wherein the insulating layer has a plurality of openings for electrical connection with the plurality of light emitting components. In the liquid crystal display device according to any one of claims 1 to 3,
The flexible wiring board has a connector at an end in the length direction,
The liquid crystal display device, wherein the connector is electrically connected to the plurality of light emitting components by the plurality of wiring patterns. The liquid crystal display device according to claim 4,
The plurality of light emitting components are divided into a plurality of groups, and each of the groups includes the same number of the light emitting components,
The plurality of layers of wiring patterns are characterized in that the light emitting components belonging to each one of the groups are connected in parallel, and the light emitting components in the same order of arrangement in different groups are connected in series. Display device. The liquid crystal display device according to claim 5, wherein the plurality of layers of wiring patterns include a connection wiring extending in the length direction of the flexible wiring board,
The liquid crystal display device, wherein the wiring pattern of at least one layer other than the wiring pattern of the uppermost layer includes at least a part of the connection wiring. The liquid crystal display device according to claim 6,
The wiring pattern of the uppermost layer includes a part of the connection wiring,
The part of the connection wiring included in the wiring pattern in the uppermost layer passes through a region adjacent to the light emitting component of the group closest to the connector on the first side end side. Display device. The liquid crystal display device according to claim 7,
The part of the connection wiring included in the wiring pattern in the uppermost layer includes a region adjacent to the light emitting component of the remaining group except the group closest to the connector on the first side end side. A liquid crystal display device characterized by being avoided.

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