Backlight unit and display device

Abstract

The backlight unit has: an LED substrate having a first main surface and a second main surface opposite to the first main surface; a plurality of LED elements arranged on the first main surface; one or more IC elements for driving arranged on the second main surface; a base arranged on the second main surface of the LED substrate; and one or more IC element covers respectively in direct or indirect contact with corresponding ones of the one or more IC elements for driving, the base having one or more protrusions respectively corresponding to the one or more IC elements for driving, the one or more protrusions respectively having an opening portion exposing the corresponding IC element for driving when viewed from a normal direction of the second main surface, and the IC element cover being fitted with the protrusion.

Description

Technical Field

[0001] The present invention relates to a backlight unit for a display device such as a liquid crystal display device, and a display device having such a backlight unit. Background Technology

[0002] Liquid crystal display devices equipped with backlight units using multiple LED elements are widely used. Previously, cooling of the driver ICs used to drive the LED elements was mostly achieved using heat sinks, as described in Patent Document 1. Furthermore, in the past, in addition to an LED substrate housing multiple LED elements, a driver substrate housing multiple driver ICs for driving the LED elements was often prepared, and these were connected via wiring. However, in recent years, to achieve thinner backlight devices, a (DOB) structure (Driver on Board) has been developed, in which the driver ICs are mounted on the back of the LED substrate. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 11-251496 Summary of the Invention The technical problem to be solved by the present invention

[0004] However, heat sinks are relatively expensive and also have a large size. Furthermore, in a DOB (Device Overhead) structure, a heat dissipation structure that prevents dust intrusion and light leakage is desired.

[0005] The purpose of this invention is to provide a backlight unit having a DOB structure that can reduce dust intrusion and light leakage while efficiently cooling the driving IC components, and a display device having such a backlight unit. Solution for solving the problem

[0006] According to embodiments of the present invention, solutions described in the following items are provided.

[0007] [Project 1] A backlight unit having: The LED substrate has a first main surface and a second main surface opposite to the first main surface; Multiple LED elements are arranged on the first main surface; One or more driver IC components are configured on the second main surface; A base, disposed on the second main surface side of the LED substrate; and One or more IC component covers are in direct or indirect contact with corresponding driving IC components among the one or more driving IC components. The base has one or more protrusions corresponding to each of the one or more driving IC components. Each of the one or more protruding portions has an opening that exposes the corresponding driving IC element when viewed from the normal direction of the second main surface. The IC component cover fits into the protrusion.

[0008] [Item 2] As described in Item 1, the backlight unit has an IC element cover with a recess for the protrusion to be inserted.

[0009] [Item 3] As described in Item 1, the backlight unit has an IC element cover having a protrusion that is embedded in the opening of the protrusion.

[0010] [Item 4] As described in Item 3, when viewed from the normal direction of the second main surface, the protrusion has a square shape.

[0011] [Item 5] As described in Item 3, the convex portion has a generally quadrilateral shape when viewed from the normal direction of the second main surface.

[0012] [Item 6] As described in any one of Items 1 to 5, when viewed from the normal direction of the second main surface, the IC element cover is larger than the protrusion.

[0013] [Item 7] The backlight unit as described in any one of Items 1 to 6, wherein the IC element cover has an extended portion extending in a direction substantially perpendicular to the second main surface.

[0014] [Item 8] The backlight unit as described in any one of Items 1 to 7 further includes a heat sink disposed between the driving IC element and the IC element cover.

[0015] [Item 9] The backlight unit as described in any one of Items 1 to 8 further comprises a heat insulation sheet disposed between the base and the IC component cover.

[0016] [Item 10] As described in Item 9, the heat insulation sheet is a double-sided adhesive sheet.

[0017] [Item 11] As described in any one of Items 1 to 10, the base and the IC component cover are fixed by screws.

[0018] [Item 12] The backlight unit as described in any one of Items 1 to 11, wherein the protrusion is formed by deep drawing.

[0019] [Item 13] The backlight unit as described in any one of items 1 to 11, wherein the protrusion is formed by a semi-punching process.

[0020] [Item 14] The backlight unit as described in any one of Items 3 to 5, wherein the protrusion is formed by a semi-punching process.

[0021] [Item 15] The display device includes: a backlight unit as described in any one of Items 1 to 14; and a display panel disposed on the first main surface side of the LED substrate. Invention Effects

[0022] According to an embodiment of the present invention, a backlight unit having a DOB structure is provided, which can reduce dust intrusion and light leakage, and can efficiently cool the driving IC components, and a display device having such a backlight unit is provided. Attached Figure Description

[0023] Figure 1 This is a schematic perspective view of a liquid crystal display device 300 including a backlight unit 100 according to an embodiment of the present invention. Figure 2 This is a schematic exploded perspective view of the liquid crystal display device 300. Figure 3 It is along Figure 1 A schematic cross-sectional view of the OLED display device 100A along line III-III'. Figure 4 This is a schematic perspective view showing the first main surface S1 side of the LED substrate 20. Figure 5 This is a schematic perspective view showing the second main surface S2 side of the LED substrate 20. Figure 6 This is a schematic cross-sectional view of a portion of a backlight unit 100A according to an embodiment of the present invention, including the IC element 24. Figure 7 This is a schematic exploded perspective view of the base 10A of the backlight unit 100A, including the protrusion 10P1. Figure 8 This is a schematic cross-sectional view of a portion of a backlight unit 100B according to an embodiment of the present invention, including an IC element 24. Figure 9 This is a schematic exploded perspective view of the base 10B of the backlight unit 100B, including the protrusion 10P2. Figure 10 This is a schematic cross-sectional view of the portion of the comparative example backlight unit 900A including IC element 24. Figure 11 This is a schematic perspective view of the base 90A of the backlight unit 900A, including the protrusion 90P1. Figure 12This is a schematic cross-sectional view of the portion of the comparative example backlight unit 900B including IC element 24. Figure 13 This is a schematic perspective view of the base 90B of the backlight unit 900B, including the protrusion 90P2. Figure 14 This is a schematic cross-sectional view of the backlight unit 900C of the comparative example, including the IC element 24. Figure 15 This is a schematic exploded perspective view of the base 90C of the backlight unit 900C, including the opening 90a. Figure 16 This is a schematic cross-sectional view of the backlight unit 900D of the comparative example, including the IC element 24. Figure 17 This is a schematic cross-sectional view of a portion of a backlight unit 100C according to an embodiment of the present invention, including an IC element 24. Figure 18 This is a schematic exploded perspective view of the base 10A of the backlight unit 100C, including the protrusion 10P1. Figure 19 This is a schematic cross-sectional view of a portion of a backlight unit 100D according to an embodiment of the present invention, including an IC element 24. Figure 20 This is a schematic exploded perspective view of the base 10A of the backlight unit 100D, including the protrusion 10P1. Figure 21 This is a schematic cross-sectional view of a portion of a backlight unit 100E according to an embodiment of the present invention, including an IC element 24. Figure 22 This is a schematic exploded perspective view of the base 10B of the backlight unit 100E, including the protrusion 10P2. Figure 23 This is a schematic cross-sectional view of a portion of a backlight unit 100F including an IC element 24 according to an embodiment of the present invention. Figure 24 This is a schematic exploded perspective view of the base 10B of the backlight unit 100F, including the protrusion 10P2. Figure 25 This is a schematic cross-sectional view of a portion of a backlight unit 100G according to an embodiment of the present invention, including the IC element 24. Figure 26 This is a schematic exploded perspective view of the base 10C of the backlight unit 100G, including the protrusion 10P1. Figure 27 This is a schematic cross-sectional view of a portion of a backlight unit 100H according to an embodiment of the present invention, including the IC element 24. Figure 28 This is a schematic exploded perspective view of the base 10D of the backlight unit 100H, including the protrusion 10P2. Figure 29 This is a schematic cross-sectional view of a portion of a backlight unit 100I according to an embodiment of the present invention, including an IC element 24. Figure 30 This is a schematic exploded perspective view of the base 10B of the backlight unit 100I, including the protrusion 10P2. Figure 31 This is a schematic cross-sectional view of a portion of a backlight unit 100J according to an embodiment of the present invention, including the IC element 24. Figure 32 This is a schematic exploded perspective view of the base 10B of the backlight unit 100J, including the protrusion 10P2. Figure 33 This is a schematic top view showing an example of an IC element 24 and an electronic component 32 disposed within the opening 10a of the protrusion 10P2. Figure 34 This is a schematic cross-sectional view of the backlight unit 100B having electronic components 32 near the IC element 24. Figure 35A This is a schematic cross-sectional view (left-right direction) of the backlight unit 100I having electronic components 32 near IC element 24. Figure 35B This is a schematic cross-sectional view (vertical direction) of the backlight unit 100I having electronic components 32 near the IC element 24. Figure 36 This is a schematic cross-sectional view of the backlight unit 100J having electronic components 32 near the IC element 24. Figure 37 This is a schematic exploded perspective view of the base 10B of the backlight unit 100K according to an embodiment of the present invention, including the protrusion 10P2. Figure 38 This is a schematic cross-sectional view of the backlight unit 100K, including IC element 24 and electronic components 32. Detailed Implementation

[0024] Hereinafter, a backlight unit and a display device according to embodiments of the present invention will be described. Here, a backlight unit used in a liquid crystal display device will be used as an example to describe the backlight unit of the embodiments of the present invention, but the backlight unit and display device of the embodiments of the present invention are not limited to the examples. The backlight unit of the embodiments of the present invention can also be used, for example, in a display device having a transmissive display panel other than a liquid crystal display panel.

[0025] The backlight unit according to an embodiment of the present invention includes an LED substrate, a plurality of LED elements, one or more driving IC elements (in the following example, a plurality of driving IC elements), a base, and one or more IC element covers (in the following example, a plurality of IC element covers). The LED substrate has a first main surface and a second main surface opposite to the first main surface. The plurality of LED elements are arranged on the first main surface, and one or more driving IC elements are disposed on the second main surface. The base is disposed on the second main surface side of the LED substrate. The one or more IC element covers are respectively disposed in direct or indirect contact with the corresponding driving IC elements among the one or more driving IC elements. The base has one or more protrusions (in the following example, a plurality of protrusions) corresponding to the one or more driving IC elements respectively. The one or more protrusions respectively define the outer edge of the space surrounding the corresponding driving IC element, and the one or more protrusions respectively have an opening that exposes the corresponding driving IC element when viewed from the normal direction of the second main surface of the LED substrate 20.

[0026] The IC component cover and the protrusion of the base are fitted together. The IC component cover may have a recess for the protrusion of the base to be inserted, or it may have a protrusion that is inserted into the opening of the protrusion of the base. A driving IC component is housed in the space formed by the second main surface of the LED substrate 20, the protrusion of the base, and the IC component cover fitted with the protrusion. The space formed by the second main surface of the LED substrate 20, the protrusion of the base, and the IC component cover fitted with the protrusion has a degree of airtightness that prevents dust from entering. The base and the IC component cover are made of a metal material with high thermal conductivity, such as aluminum alloy. The protrusion of the base may be formed, for example, by deep drawing or semi-punching. In addition, the protrusion of the IC component cover may be formed, for example, by semi-punching. The driving IC component and the IC component cover may be in direct contact, or they may be in indirect contact, for example, through a heat sink. As long as the structure allows the heat of the driving IC component to be transferred to the IC component cover through contact heat conduction, it is acceptable.

[0027] On the other hand, to reduce direct heat conduction from the base to the IC component cover, a heat insulation sheet can be placed between the base and the IC component cover. The base and IC component cover can be secured, for example, with screws or with double-sided adhesive tape. Of course, both screws and double-sided adhesive tape can also be used simultaneously. The double-sided adhesive tape can also function as the aforementioned heat insulation sheet.

[0028] Hereinafter, a backlight unit and a display device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0029] Figure 1 This is a schematic perspective view of a liquid crystal display device 300 including a backlight unit according to an embodiment of the present invention. Figure 2This is an exploded perspective view of the liquid crystal display device 300. Additionally, Figure 3 It is along Figure 1 A schematic cross-sectional view of the liquid crystal display device 300 with line III-III' in the middle.

[0030] The liquid crystal display device 300 includes a backlight unit 100, a liquid crystal display panel unit (hereinafter referred to as a display panel unit) 200, and an optical element group 40 disposed between the backlight unit 100 and the display panel unit 200.

[0031] The backlight unit 100 includes a base (backlight base) 10, an LED substrate 20, and a reflective sheet 30 disposed on a first main surface of the LED substrate 20. The reflective sheet 30 has holes that expose a plurality of LED elements 22 disposed on the first main surface of the LED substrate 20, and reflects light emitted from the LED elements 22 toward the display panel unit 200, thereby improving light utilization efficiency. Alternatively, the reflective sheet 30 may be omitted.

[0032] The display panel unit 200 includes a liquid crystal display panel (hereinafter referred to as the display panel) 60, a panel base 50 configured to hold the display panel 60, and a bezel 70. Cushioning materials C1 and C2 (see reference 1) are respectively disposed between the display panel 60 and the bezel 70 and between the display panel 60 and the panel base 50. Figure 3 The bezel 70 is configured to cover the display panel 60, the panel base 50, the optical assembly 40, and the backlight unit 100.

[0033] The display panel 60 includes: a liquid crystal cell having a pair of substrates and a liquid crystal layer disposed between the pair of substrates; a polarizing plate disposed on both sides of the liquid crystal cell; and a retardation plate disposed between the liquid crystal cell and the front polarizing plate as needed. The pair of substrates of the liquid crystal cell include a structure for applying a voltage to the liquid crystal layer. The display panel 60 can be a known transmissive liquid crystal display panel.

[0034] Depending on the structure of the display panel 60, the optical element group 40 may include multiple optical elements 42, 44, and 46. The optical element group 40 may include, for example, a light diffuser (sometimes also called a "diffuser") 46, and brightness enhancement films 44 and 42. Alternatively, the optical element group 40 may also have a structure such as a light diffuser / lens / lens / light diffuser. There are no particular limitations on the type and number of optical elements constituting the optical element group 40. Furthermore, the optical element group 40 may be omitted. A buffer material C3 (see reference) is disposed between the optical element group 40 and the panel base 50. Figure 3 When the panel base 50 is made of resin, the cushioning material C3 can be omitted.

[0035] like Figure 2As shown, the base 10 has multiple protrusions 10P. Heat sinks 12 can be disposed on each protrusion 10P. Alternatively, the heat sinks 12 can be omitted.

[0036] Reference Figures 4-7 The structure of the backlight unit 100A according to an embodiment of the present invention will be explained.

[0037] Figure 4 This is a schematic perspective view showing the first main surface S1 side of the LED substrate 20. Figure 5 This is a schematic perspective view showing the second main surface S2 side of the LED substrate 20.

[0038] like Figure 4 As shown, a plurality of LED elements 22 are disposed on the first main surface S1 of the LED substrate 20, such as Figure 5 As shown, a plurality of driving IC elements (hereinafter referred to as "IC elements") 24 are arranged on the second main surface S2 of the LED substrate 20. Each of the plurality of IC elements 24 drives a plurality of LED elements 22. Here, an example is shown where three IC elements 24 are respectively positioned for 96 LED elements 22, but this is not a limitation. The number and arrangement of the IC elements 24 can vary depending on the number and range of LED elements 22 controlled by each IC element. Additionally, the LED substrate 20 is provided with connectors (not shown) for receiving power and / or signals.

[0039] Figure 6 This is a schematic cross-sectional view of the backlight unit 100A, including the IC element 24. Figure 7 This is a schematic exploded perspective view of the base 10A of the backlight unit 100A, including the protrusion 10P1.

[0040] like Figure 6 As shown, a base 10A is disposed on the second main surface S2 side of the LED substrate 20. An IC element cover 14A1 is disposed on the IC element 24IC disposed on the second main surface S2 of the LED substrate 20, indirect contact with it via a heat sink 12. Alternatively, the heat sink 12 can be omitted, and the IC element cover 14A1 can be disposed in direct contact with the IC element 24. The IC element cover 14A1 is, for example, fixed by a screw 17 in a screw hole 10c provided on a protrusion 10P1 of the base 10A.

[0041] The base 10A has multiple protrusions 10P1 that define the outer edge of the space SP1 surrounding the corresponding IC element 24. Each protrusion 10P1 has an opening 10a that exposes the corresponding IC element 24 when viewed from the normal direction of the second main surface S2, and the IC element cover 14A1 is fitted into the protrusion 10P1. The IC element 24 is housed within the space formed by the second main surface S2 of the LED substrate 20, the protrusions 10P1 of the base 10A, and the IC element cover 14A1 fitted into the protrusions 10P1. The protrusions 10P1 of the base 10A are formed, for example, by deep drawing, and have a side surface that is inclined relative to the second main surface S2.

[0042] The IC component cover 14A1 illustrated here has a protrusion 14p that fits into the opening 10a of the protrusion 10P1. The protrusion 14p has a side surface substantially perpendicular to the second main surface S2, and is fitted into the opening 10a such that this side surface faces the inner side surface of the opening 10a. The IC component cover 14A1 is fitted into the protrusion 10P1 via the protrusion 14p. The protrusion 14p is formed, for example, by a semi-punching process. The IC component cover 14A1 has a relatively simple shape and can be easily manufactured using a stamping process with a die, thus reducing costs compared to using a heat sink.

[0043] The gap in the fitting structure of the protrusion 14p of the IC component cover 14A1 embedded in the opening 10a of the protrusion 10P1 has a portion that is approximately parallel to the second main surface S2 and a portion that is approximately perpendicular to the second main surface S2. Figure 6 The cross-section shown has a stepped shape. Therefore, dust and the like can hardly pass through the gap in the interlocking structure formed by the protrusion 10P1 and the IC component cover 14A1, which has excellent dustproof properties. That is, the space formed by the second main surface S2 of the LED substrate 20, the protrusion 10P1 of the base 10A, and the IC component cover 14A1 that interlocks with the protrusion 10P1 has a degree of airtightness that prevents dust from entering.

[0044] In the backlight unit 100A, a heat sink 12 is disposed between the IC element 24 and the IC element cover 14A1. The heat sink 12 is smaller than the opening 10a and is disposed within the opening 10a. The heat sink 12 contacts the IC element 24 and the IC element cover 14A1, transferring the heat of the IC element 24 to the IC element cover 14A1. The heat sink 12 may be omitted. When the heat sink 12 is omitted, the IC element cover 14A1 is in direct contact with the IC element 24. The IC element cover 14A1 is preferably formed of a metal material with high thermal conductivity (e.g., aluminum alloy). In addition, by studying the shape of the IC element cover 14A1 and increasing its surface area, the heat dissipation effect can be improved. The heat of the IC element cover 14A1 dissipates into the air. The IC element cover 14A1 illustrated here has approximately the same size as the flat upper surface of the protrusion 10P. Of course, to improve heat dissipation, the IC element cover 14A1, etc., can be enlarged in various ways by increasing the surface area, as illustrated later.

[0045] In the backlight unit 100A, a heat insulation sheet 16 is disposed between the base 10 (protrusion 10P1) and the IC component cover 14A1. The base 10 can also be heated by the heat emitted by the LED element 22. When the heat of the base 10 is transferred to the IC component cover 14A1, the heat of the IC element 24 cannot be effectively dissipated. The heat insulation sheet 16 reduces the transfer of heat from the base 10 to the IC component cover 14A1. The heat insulation sheet 16 is, for example, formed of a resin (including rubber or elastomer) with low thermal conductivity.

[0046] like Figure 7 As shown, the IC component cover 14A1 is mounted on the protrusion 10P1 of the base 10A. Figure 7 This is a schematic exploded perspective view of the base 10A including the protrusion 10P1, with the portion of the base 10A other than the protrusion 10P1 omitted.

[0047] A heat sink 12 is arranged to contact the IC component (not shown) exposed within the opening 10a of the protrusion 10P1. A heat insulation sheet 16, having an opening 16a and a screw opening 16c, is arranged to match the opening 10a and screw hole 10c of the protrusion 10P1. Next, an IC component cover 14A1 is mounted by fitting the protrusion 14p into the opening 10a. At this time, the IC component cover 14A1 can be easily positioned using the fitting structure with the opening 10a. The opening 10a and the protrusion 14p are preferably generally rectangular (quadrilaterals with all interior angles of 90°) to match the shape of the IC component 24 (generally rectangular). If it is generally rectangular, the orientation in the plane parallel to the second main surface S2 is also restricted compared to, for example, a circle, thus enabling efficient positioning. Furthermore, a generally rectangular shape includes, for example, a rectangle with rounded corners.

[0048] Next, screws 17 are passed through the screw opening 14c of the IC component cover 14A1 and the screw opening 16c of the heat insulation plate 16, and screws 17 are tightened into the screw holes 10c of the protrusion 10P1 of the base 10A to fix the IC component cover 14A1 to the protrusion 10P1 of the base 10A. Compared with a heat sink, the IC component cover 14A1 can be easily removed using screws 17, which is also an advantage.

[0049] The number, density, and current of the LED elements 22 are determined based on the brightness required by the backlight unit 100A. Consequently, the heat generation of the LED elements 22 and the IC elements 24 differs. Depending on the required heat dissipation performance, the heat sink 12 and / or the heat insulation sheet 16 can be omitted.

[0050] Next, refer to Figure 8 and Figure 9 The structure of another backlight unit 100B according to an embodiment of the present invention will be described. Figure 8 This is a schematic cross-sectional view of the backlight unit 100B, including the IC element 24. Figure 9 This is a schematic exploded perspective view of the base 10B of the backlight unit 100B, including the protrusion 10P2.

[0051] The shape of the protrusion 10P2 of the base 10B of the backlight unit 100B is similar to... Figure 6 and Figure 7 The shape of the protrusion 10P1 on the base 10A of the backlight unit 100A shown is different. In the following figures, constituent elements with substantially the same function are shown with the same reference numerals, and descriptions are sometimes omitted.

[0052] Protrusion 10P1 has a side surface inclined relative to the second main surface S2, while protrusion 10P2 has a side surface substantially perpendicular to the second main surface S2. Protrusion 10P2 can be formed, for example, by a half-punching process. Therefore, the width Y of protrusion 10P2 can be smaller than the width X of protrusion 10P1. In this case, for example... Figure 8 As shown, the size of the protrusion 10P2 is approximately equal to the size of the IC component cover 14A1.

[0053] Thus, the area of ​​protrusion 10P2 can be smaller than the area of ​​protrusion 10P1. That is, the area of ​​the space SP2 defined by protrusion 10P2 can be smaller than the area of ​​the space SP1 defined by protrusion 10P1 (see reference). Figure 6 The area of ​​space SP2 is small. For example, if the area of ​​space SP2 is small... Figure 8 Like the LED element 22(L) on the left side, the number of LED elements 22 arranged opposite to the space SP2 via the LED substrate 20 can be reduced. Figure 8The LED element 22(L) on the left side of the LED substrate 20, which indirectly contacts the base 10B, is more difficult to dissipate heat. Therefore, it is preferable to... Figure 8 The number of LED elements 22 arranged as in the left-hand LED element 22(L) is small.

[0054] like Figure 9 As shown, the IC component cover 14A1 is mounted on the protrusion 10P2 of the base 10B. The mounting sequence is as follows: Figure 7 The explanation is the same, so it is omitted here.

[0055] Furthermore, depending on the structure of the base plate, sometimes semi-punching is not possible to ensure sufficient height. For example, when the aluminum plate forming the base is thin, or when the height of electronic components (such as capacitors or resistors) positioned around IC components or surrounding components is large, semi-punching is sometimes not feasible. In such cases, deep drawing is used, for example, with reference to... Figure 6 as well as Figure 7 The structure described is sufficient.

[0056] Next, refer to Figures 10-16 This section describes the structure of the portion of the backlight unit containing the IC element 24 in the comparative example.

[0057] Next, refer to Figure 10 and Figure 11 This illustrates the backlight unit 900A of the comparative example. Figure 10 This is a schematic cross-sectional view of the backlight unit 900A, including the IC element 24. Figure 11 This is a schematic perspective view of the base 90A, including the protrusion 90P1. The backlight unit 900A has a simple structure in which the IC element 24 is covered only by the protrusion 90P1 formed in the base 90A through a deep drawing process. Due to the heat generated by the LED element 22, the LED substrate 20 is heated, and via the LED substrate 20, the base 90A is also heated. Furthermore, since the IC element 24 also generates heat, the space SP9a surrounding the IC element 24 becomes hotter than the ambient temperature, potentially causing malfunctions of the IC element 24. In other words, the backlight unit 900A may not have sufficient heat dissipation characteristics.

[0058] Next, refer to Figure 12 and Figure 13 This illustrates the backlight unit 900B of the comparative example. Figure 12 This is a schematic cross-sectional view of the backlight unit 900B, including the IC element 24. Figure 13This is a schematic perspective view of the portion of the base 90B including the protrusion 90P2. The backlight unit 900B has a hole 90h formed in the protrusion 90P2 of the base 90B by a deep drawing process. A heat sink 12 is disposed on the IC element 24 so that the base 90B indirectly contacts the IC element 24 via the heat sink 12. Although the heat sink 12 can be confirmed to be disposed via the hole 90h, if the heat sink 12 is not disposed correctly, it cannot be repositioned without removing the LED substrate 20 from the base 90B. In contrast, in the backlight unit 100A or 100B according to the above-described embodiment of the present invention, the heat sink 12 can be disposed with the LED substrate 20 mounted on the base 10A or 10B.

[0059] Next, refer to Figure 14 and Figure 15 This illustrates the backlight unit 900C of the comparative example. Figure 14 This is a schematic cross-sectional view of the backlight unit 900C, including the IC element 24. Figure 15 This is a schematic exploded perspective view of the base 90A, including the opening 90a. The base 90C of the backlight unit 900C has an opening 90a that exposes the IC component 24. In the backlight unit 900C, with the LED substrate 20 mounted on the base 90C, a heat sink 12 can be configured; however, an adhesive (including a bonding agent) is needed to mount the heat sink 12 onto the IC component 24, raising concerns about the reliability of the bonding. Furthermore, dust may enter the gap between the LED substrate 20 and the base 90C through the opening 90a. Additionally, light leakage may occur from the opening 90a.

[0060] Next, refer to Figure 16 This section describes the comparative example of the backlight unit 900D. The backlight unit 900D and... Figure 8 The difference between the backlight unit 100B and the one shown lies in the structure of the IC component cover 94A. The IC component cover 14A1 of the backlight unit 100B has a structure with a protrusion 14p and an opening 10a that embeds into the protrusion 10P2 of the base 10B. However, the IC component cover 94A of the backlight unit 900D is a parallel flat plate and does not form an interlocking structure with the protrusion 10P2 of the base 10B. Therefore, when mounting the IC component cover 94A on the base 10B, it is impossible to use the opening 10a for positioning, reducing workability, or requiring an additional positioning structure.

[0061] Furthermore, in the backlight unit 100B, since the protrusion 10P2 and the protrusion 14p of the IC component cover 14A1 form a fitting structure, the gap between the protrusion 10P2 and the IC component cover 14A1 is... Figure 8The cross-section shown has a stepped shape. In contrast, in the backlight unit 900D, since the protrusion 10P2 and the IC component cover 94A do not form a fitting structure, the gap between the protrusion 10P2 and the IC component cover 94A is... Figure 16 The cross-section shown is straight, which reduces the effectiveness of dust intrusion.

[0062] As can be understood from a comparison with backlight units 900A to 900D, backlight units 100A and 100B according to embodiments of the present invention have various advantages.

[0063] Next, the structure of a backlight unit according to another embodiment of the present invention will be described. As illustrated below, backlight units 100A and 100B can maintain the above-described effects and can be modified in various ways.

[0064] Next, refer to Figures 17-24 An example illustrating the deformation of the IC component cover.

[0065] First, refer to Figure 17 and Figure 18 This describes the IC element cover 14A2 of another backlight unit 100C according to an embodiment of the present invention. Figure 17 This is a schematic cross-sectional view of the backlight unit 100C, including the IC element 24. Figure 18 This is a schematic exploded perspective view of the base 10A of the backlight unit 100C, including the protrusion 10P1. The backlight unit 100C, in addition to the IC component cover 14A2, can also be connected to... Figure 6 The backlight unit 100A shown is substantially the same; therefore, structural elements with the same function are indicated by the same reference numerals, and descriptions are omitted.

[0066] The backlight unit 100C has an IC component cover 14A2 with an extended portion 14A2e around the IC component cover 14A1 of the backlight unit 100A. That is, the surface area of ​​the IC component cover 14A2 is larger than that of the IC component cover 14A1, resulting in excellent heat dissipation.

[0067] Next, refer to Figure 19 and Figure 20 This describes the IC element cover 14A3 of another backlight unit 100D according to an embodiment of the present invention. Figure 19 This is a schematic cross-sectional view of the backlight unit 100D, including the IC element 24. Figure 20 This is a schematic exploded perspective view of the base 10A of the backlight unit 100D, including the protrusion 10P1. The backlight unit 100D, in addition to the IC component cover 14A3, can also be connected to... Figure 6 The backlight unit 100A shown is essentially the same.

[0068] The IC component cover 14A3 of the backlight unit 100D has an extension portion 14A3e extending in a direction substantially perpendicular to the second main surface S2 around the periphery of the IC component cover 14A1 of the backlight unit 100A. The thickness of the extension portion 14A3e is, for example, the same as the thickness of the IC component cover 14A1, and the length of the extension portion 14A3e is greater than the thickness of the IC component cover 14A1. That is, the surface area of ​​the IC component cover 14A3 is larger than that of the IC component cover 14A1, and the surface area is larger than that of the IC component cover 14A2, thus resulting in better heat dissipation.

[0069] Next, refer to Figure 21 , Figure 22 , Figure 23 and Figure 24 Other backlight units 100E and 100F according to embodiments of the present invention are described below. Figure 21 This is a schematic cross-sectional view of the backlight unit 100E, including the IC element 24. Figure 22 This is a schematic exploded perspective view of the base 10B of the backlight unit 100E, including the protrusion 10P2. Figure 23 This is a schematic cross-sectional view of the backlight unit 100F, including the IC element 24. Figure 24 This is a schematic exploded perspective view of the base 10B of the backlight unit 100F, including the protrusion 10P2. Figure 21 and Figure 22 The backlight unit 100E shown, except for the IC component cover 14A2, can be connected with... Figure 8 The backlight unit shown is the same as 100B. Figure 23 and Figure 24 The backlight unit 100F shown, except for the IC component cover 14A3, can be connected with... Figure 8 The backlight unit 100B shown is identical. Backlight units 100E and 100F each have an IC component cover 14A2 (see reference). Figure 21 ) and IC component cover 14A3 (refer to Figure 23 Therefore, as mentioned above, it has excellent heat dissipation characteristics.

[0070] IC component covers 14A2 and 14A3 can be formed, for example, by stamping aluminum plates, thus offering superior mass production capabilities, lower cost, and easier installation compared to heat sinks.

[0071] Next, refer to Figure 25 , Figure 26 , Figure 27 and Figure 28 This section describes other backlight units 100G and 100H according to embodiments of the present invention. Figure 25 This is a schematic cross-sectional view of the backlight unit 100G, including the IC element 24. Figure 26 This is a schematic exploded perspective view of the base 10C of the backlight unit 100G, including the protrusion 10P1. Figure 27 This is a schematic cross-sectional view of the backlight unit 100H, including the IC element 24. Figure 28 This is a schematic exploded perspective view of the base 10D of the backlight unit 100H, including the protrusion 10P2.

[0072] Backlight units 100G and 100H are respectively replaced by adhesive layer 15. Figure 6 The backlight unit 100A shown is Figure 8 The backlight unit 100B shown depicts a structure where the IC component cover 14A1 is fixed with screws. The adhesive layer 15 is, for example, double-sided tape. The adhesive layer 15 also functions as a heat insulation sheet in the backlight units 100A and 100B. The bases 10C and 10D of the backlight units 100G and 100H, respectively, and the IC component covers 14A4 and 14A5, do not have holes for screws, thus reducing the size of the structure used to fix the IC component covers 14A4 and 14A5. Using the adhesive layer 15 also reduces costs.

[0073] Next, refer to Figure 29 and Figure 30 The structure of other backlight units 100 according to embodiments of the present invention will be explained. Figure 29 This is a schematic cross-sectional view of the backlight unit 100I, including the IC element 24. Figure 30 This is a schematic exploded perspective view of the base 10B of the backlight unit 100I, including the protrusion 10P2. The backlight unit 100I, in addition to the IC component cover 14A6, can also be connected to... Figure 8 The backlight unit 100B shown is essentially the same.

[0074] The IC element cover 14A6 of the backlight unit 100I differs from the quadrilateral protrusion 14p of the IC element cover 14A1 of the backlight unit 100B; it has a U-shaped protrusion 14A6p. The outer peripheral surface of the protrusion 14A6p fits into the opening 10a of the protrusion 10P2 of the base 10B. The U-shaped protrusion 14A6p forms a recess 14A6C, which increases the space in the thickness direction compared to the quadrilateral protrusion 14p. Furthermore, the recess 14A6c formed on the opposite side of the protrusion 14A6p can be formed incidentally during the stamping process of the protrusion 14A6p, but is not structurally necessary. Figure 29 The heat sink 12 shown has a cross-sectional shape. The heat sink 12 is obtained, for example, by flattening a flexible heat sink or by overlapping two heat sinks of different sizes.

[0075] Next, refer to Figure 31 and Figure 32 The structure of another backlight unit 100J according to an embodiment of the present invention will be described. Figure 31 This is a schematic cross-sectional view of the backlight unit 100J, including the IC element 24. Figure 32 This is a schematic exploded perspective view of the base 10B of the backlight unit 100J, including the protrusion 10P2. The backlight unit 100J, in addition to the IC component cover 14A7, can also be connected to... Figure 8 The backlight unit 100B shown is essentially the same.

[0076] The backlight unit 100J has an IC component cover 14A7 with an extended portion 14A7e and a recess 14A7C that is embedded in the protrusion 10P2 of the base 10B. In other words, the IC component cover 14A7 has a protrusion 14A7p that protrudes in the opposite direction to the example described above (protrusions 14p and 14A6p). By adopting such a structure, similar to the backlight unit 100I, the space in the thickness direction can be increased. In addition, the thickness of the heat sink 12 that contacts the IC component cover 14A7 and the IC component 24 is changed.

[0077] Reference Figure 33 , Figure 34 , Figure 35A , Figure 35B and Figure 36 This illustrates the advantages of its backlight units 100I and 100J. Figure 33 This is a schematic top view showing an example of an IC element 24 and an electronic component 32 disposed within the opening 10a of the protrusion 10P2. Figure 34 This is a schematic cross-sectional view of the backlight unit 100B described above, where electronic components 32 are located near the IC element 24. Figure 35A and Figure 35B This is a schematic cross-sectional view of the backlight unit 100I having electronic components 32 near the IC element 24. Figure 35A It is a cross-sectional view in the left-right direction. Figure 35B It is a cross-sectional view in the vertical direction. Figure 36 This is a schematic cross-sectional view of the backlight unit 100J with electronic components 32 near the IC element 24. Additionally, in Figure 34 , Figure 35A and Figure 36 In the cross-sectional view, electronic component 32 is shown superimposed.

[0078] like Figure 33 As shown, electronic components (e.g., capacitors or resistors) 32 are sometimes arranged near IC element 24. The height of the electronic component 32 (the length in the normal direction of the second main surface S2) is sometimes greater than that of IC element 24. Thus, for example, as Figure 34 As shown, in the structure of the backlight unit 100B, there may be a situation where the electronic component 32 cannot be accommodated. In this case, as in the backlight unit 100A, forming the protrusion 10P1 by deep drawing, for example, can ensure sufficient height space. However, as mentioned above, the protrusion 10P1 formed by deep drawing is larger than the protrusion 10P2 formed by semi-punching (the projected area when viewed from the normal direction of the second main surface S2 is larger). Therefore, as... Figure 35A , Figure 35B and Figure 36 As shown, if a structure similar to that of backlight units 100I and 100J is adopted, it can be ensured that there is enough space to accommodate the electronic components 32.

[0079] In backlight units 100I and 100J, recesses 14A6C and 14A7C are formed respectively to ensure sufficient space to accommodate IC component 24 and electronic components 32. Alternatively, as shown... Figure 37 and Figure 38 As shown in the backlight unit 100K, only the height of the space housing the electronic components 32 is increased.

[0080] Figure 37 This is a schematic exploded perspective view of the base 10B of the backlight unit 100K, including the protrusion 10P2, while also showing the IC element 24 and electronic components 32 exposed at the opening 10a. Figure 38 This is a schematic cross-sectional view of the backlight unit 100K, including IC element 24 and electronic components 32. Figure 37 A cross-sectional view in the vertical direction.

[0081] The IC component cover 14A8 has a protrusion 14A8p that is embedded into the opening 10a of the base 10B. The protrusion 14A8p has a recess 14A8C at a position opposite to the electronic component 32, ensuring that there is sufficient space to accommodate the electronic component 32.

[0082] The structure of the backlight unit according to the above-described embodiments of the present invention can be appropriately combined, replaced, or modified. The backlight unit according to the embodiments of the present invention has a DOB structure, which can reduce dust intrusion and light leakage, and efficiently cool the driving IC components. The backlight unit according to the embodiments of the present invention can also be used, for example, in display devices equipped with transmissive display panels such as liquid crystal display panels.

Claims

1. A backlight unit, characterized in that, have: The LED substrate has a first main surface and a second main surface opposite to the first main surface; Multiple LED elements are arranged on the first main surface; One or more driver IC components are configured on the second main surface; A base, disposed on the second main surface side of the LED substrate; and One or more IC component covers are in direct or indirect contact with corresponding driving IC components among the one or more driving IC components. The base has one or more protrusions corresponding to each of the one or more driving IC components. Each of the one or more protruding portions has an opening that exposes the corresponding driving IC element when viewed from the normal direction of the second main surface. The IC component cover fits into the protrusion.

2. The backlight unit as described in claim 1, characterized in that, The IC component cover has a recess for the protrusion to be inserted.

3. The backlight unit as described in claim 1, characterized in that, The IC component cover has a protrusion that is embedded within the opening of the protrusion.

4. The backlight unit as described in claim 3, characterized in that, When viewed from the normal direction of the second main surface, the protrusion has a square shape.

5. The backlight unit as described in claim 3, characterized in that, When viewed from the normal direction of the second main surface, the protrusion has a generally quadrilateral shape.

6. The backlight unit as described in any one of claims 1 to 5, characterized in that, When viewed from the normal direction of the second main surface, the IC component cover is larger than the protrusion.

7. The backlight unit as described in any one of claims 1 to 5, characterized in that, The IC component cover has an extension portion extending in a direction substantially perpendicular to the second main surface.

8. The backlight unit as described in any one of claims 1 to 5, characterized in that, It also has a heat sink disposed between the driving IC element and the IC element cover.

9. The backlight unit as described in any one of claims 1 to 5, characterized in that, It also has a heat insulation sheet disposed between the base and the IC component cover.

10. The backlight unit as described in claim 9, characterized in that, The heat insulation sheet is a double-sided adhesive sheet.

11. The backlight unit as described in any one of claims 1 to 5 and 10, characterized in that, The base and the IC component cover are secured with screws.

12. The backlight unit as described in any one of claims 1 to 5 and 10, characterized in that, The protrusion is formed by deep drawing.

13. The backlight unit as described in any one of claims 1 to 5 and 10, characterized in that, The protrusion is formed by a semi-punching process.

14. The backlight unit as described in any one of claims 3 to 5, characterized in that, The protrusion is formed by a semi-punching process.

15. A display device, characterized in that, include: The backlight unit according to any one of claims 1 to 14; as well as The display panel is disposed on the first main surface side of the LED substrate.

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