JP2009272451A - Surface light source module, back light unit, and liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide a surface light source module capable of simplifying the mounting and removing operations of an LED mounting substrate, increasing the light irradiation efficiency, and efficiently introducing light into a diffusion plate.
An LED mounting substrate 3 on which a large number of LEDs 2 sealed with a transparent lens 12 are mounted is formed with a member that has a plurality of holes at positions corresponding to the positions of the lenses 12 and reflects light at least on the front side. The bottom surface of the substrate was brought into close contact with the surface of the heat dissipation member and fixed by sandwiching the substrate cover 10 with the heat dissipation member 10 formed of a heat conductive metal.
[Selection] Figure 5

Description

  The present invention relates to a surface light source module using a solid light emitting element such as a light emitting diode as a light source and its application device, and is suitable for a backlight unit of a liquid crystal display device, for example.

  In recent years, a light source of a backlight device for a liquid crystal display device has been replaced by a solid light emitting element represented by a light emitting diode (LED) instead of a conventional cold cathode fluorescent lamp. Here, description will be made using an LED as the solid-state light emitting element. This alternative movement is largely due to the fact that LEDs do not contain mercury and are suitable as environmentally friendly light sources, and that the luminous efficiency of LEDs has improved dramatically in recent years. The backlight device using LED as a light source has been used for a liquid crystal display device of a mobile phone or a mobile device having a relatively small display area, but recently, a liquid crystal monitor of a nominal 20-inch type or more, the same 30-inch liquid crystal monitor. The movement to adopt it as a backlight unit incorporated in large-screen display devices such as liquid crystal televisions of the type or larger is also becoming active.

  As backlight units for large-screen liquid crystal display devices, there are a so-called direct type, in which high luminance is easily realized structurally, and an edge light type, in which thinning and cost reduction are easy to realize. In the case of a direct type backlight unit, a surface light source module is formed by mounting a plurality of LEDs on an LED mounting substrate to form a surface light source module, and arranging the plurality of surface light source modules on a heat dissipation member. A light diffusing plate, a diffusing sheet, a lens sheet, and the like are arranged on the surface light emitting unit side of the surface light source module to constitute a backlight unit of the liquid crystal display device.

  FIG. 8 is a schematic diagram for explaining an example of the structure of a surface light source module of a conventional direct-type backlight unit. FIG. 8A is a cross-sectional view taken along the longitudinal direction of the LED mounting substrate, and FIG. FIG. 9 is a top view of the main part of FIG. A plurality of LEDs 2 are arranged and mounted on the upper surface of the LED mounting substrate 3. A plurality of the LED mounting substrates 3 are arranged on the upper surface side of the bottom of the box-shaped heat radiating member 1 whose upper surface is opened, and a reflection sheet 15 is provided between the LEDs 2 to form a surface light source module. The heat dissipating member 1 constitutes the casing of the backlight unit, and various optical compensation sheet laminates for light diffusion and condensing are arranged on the upper surface side. Assembled.

  As described above, in the backlight unit in which the LED mounting substrate 3 (hereinafter also simply referred to as a substrate) mounted with the LED 2 as a light source is accommodated in the heat radiating member 1, particularly on the screen of the liquid crystal display panel when the light emitting area is increased. In order to ensure luminance, it is necessary to increase the number of substrates 3 on which the LEDs 2 are mounted. And in order to dissipate the heat_generation | fever of LED2 which increases with the increase in the number of the board | substrates 3 and to maintain luminous efficiency, it is common to use the above heat radiating members 1 as a housing | casing. Needless to say, a housing may be provided separately from the heat dissipation member 1.

  In order to ensure high-quality video display on a large screen display device, it is required to improve the uniformity of color and brightness on the screen. In order to satisfy this requirement, it is necessary to increase the LED mounting density on the substrate 3 on which the LEDs 2 are mounted. On the other hand, variations in light emission characteristics (luminance characteristics) between the substrates 3 occur due to large variations in the light characteristics of the individual LEDs 2 mounted on the substrate 3. When a large number of substrates 3 with varying light emission characteristics are installed on the heat dissipating member 1 with a high density, there is a problem that the in-plane light emission variation (brightness distribution variation) of the backlight unit becomes large. In order to solve such a variation in luminance distribution, it is necessary to replace the substrate 3.

  In conventional surface light source modules using LEDs, for example, fixing each of the substrates 3 to the heat radiating member 1 by screwing is widely employed. However, since this method requires an extra area for screw holes in each substrate 3, there is a problem that high-density mounting is hindered. Further, when a ceramic substrate is used as the substrate 3, there is a problem that when a screw hole is provided on the substrate, cracks are easily generated in the substrate, so that the product yield is reduced and the cost is increased.

  As another mounting method for installing the substrate 3 on the heat radiating member 1, a method using fixing means such as bonding using an adhesive or bonding using solder to the heat radiating member 1 is also employed. However, when these fixing means are used, the substrate 3 cannot be easily peeled off from the heat radiating member 1, and many work steps are required for replacing the substrate, and the substrate is damaged when the substrate is replaced. There was a drow of occurrence of troubles such as giving. These defects increase the manufacturing cost and ultimately increase the cost of the product. In particular, in a backlight unit used in, for example, a large-screen liquid crystal television, the number of substrates 3 to be mounted increases, so that the influence on the manufacturing cost is great.

  In the backlight device, a reflector (reflector) that reflects light emitted from the LED toward the observer is provided. For example, the emitted light in the side surface direction of the LED is reflected by this reflector, and the light is emitted from the upper surface.

  In many cases, the reflection sheet 15 for effectively using the emitted light of the LED has a structure installed on the surface of the substrate 3 other than the LED mounting portion as described above. However, when the reflective sheet 15 is installed on the substrate 3, the light emitted from the LED 2 is blocked by shifting the positions of the lens (not shown) installed on the substrate 3 and the opening of the reflective sheet. The light emitted from the LED 2 is shielded by bending due to thermal expansion. As a result, the irradiation efficiency of light incident on the diffusion plate (not shown) may be reduced.

  The present invention has been made in order to solve such a technical problem. The object of the present invention is to provide a structure that allows easy mounting and replacement of the LED mounting board on the heat dissipation board (housing), and An object of the present invention is to provide a surface light source module, a backlight unit, and a liquid crystal display device that have improved the irradiation efficiency of light emitted from LEDs.

  The present invention relates to an LED mounting substrate in which a large number of LEDs sealed by a transparent lens member having a semi-cylindrical shape are arranged and mounted on the surface side of a substrate formed of a heat conductive material, and the transparent lens. A substrate cover in which a plurality of holes corresponding to the number of LED mounting substrates is formed at a position corresponding to the position of the lens of the member, and a member that reflects light at least on the front side of the base material is formed or surface-treated, A surface light source integrated by fixing the LED mounting substrate in close contact with the surface of the heat dissipating member by sandwiching the LED mounting substrate between the heat dissipating member formed of a good heat conductive metal and the substrate cover A module. The heat radiating member has a flat surface on which a plurality of LED mounting substrates are arranged. The heat radiating member is preferably a box-shaped member having a low side wall with the flat surface as an inner bottom.

  In the surface light source module of the present invention, the substrate cover may be a thin plate using a metal material such as aluminum or an alloy thereof, copper or an alloy thereof, stainless steel, or the like, or may be heat conductive such as epoxy. Although it may be a curable resin or a thermoplastic resin such as a liquid crystal polymer, it is desirable to use a flexible material that can be bent with a relatively small force. A metal film such as gold, silver, aluminum, or nickel can be formed on the surface as a light reflecting member. In addition to the metal film, a so-called white film having high light reflection characteristics in the visible region, such as a resist film or a metal oxide film, can be used. Further, when a metal plate is employed as the substrate cover, high light reflection characteristics are imparted by subjecting the metal background as it is or by performing a surface treatment such as polishing. Moreover, it is desirable that the substrate cover in the surface light source module of the present invention is fixed to the heat radiating member by means of easy attachment and detachment such as screws or clips at the corners and edge portions.

  In the present invention, the surface light source module is preferably housed in a lower housing having a bottom having good heat radiation performance and an open surface light source emission side, and the surface light source emission side of the surface light source module. An optical compensation sheet laminate such as a diffusion plate, a diffusion sheet, and a lens sheet (prism sheet) is installed on the top, covered with a front frame (upper housing) having a light exit window, and integrated with the lower housing to provide a liquid crystal display device Backlight unit for use. This backlight unit is installed on the back surface of the liquid crystal display panel to obtain a liquid crystal display device.

  According to the surface light source module of the present invention, a plurality of LED mounting substrates can be simultaneously and easily attached to a heat dissipation member, and one or a plurality of LED mounting substrates are used for correcting luminance distribution, light emission failure, and the like. When replacing the LED mounting board, it is easy to remove and re-install the LED mounting board by removing the board cover. Therefore, the LED mounting board can be replaced with a simple operation. Therefore, the substrate replacement work time can be shortened and the yield of the surface light source module can be improved.

  In addition, since the present invention has a structure in which the LED mounting substrate is sandwiched between the substrate cover and the heat radiating member, the bottom surface of the LED mounting substrate is in close contact with the heat radiating member, and heat dissipation is improved. In addition, heat dissipation can be further improved by inserting a heat dissipation sheet or the like having high thermal conductivity between the LED mounting substrate and the heat dissipation member.

  In addition, since a light reflecting material is formed on the surface of the substrate cover or subjected to light reflection treatment, the light emitted from the LED is efficiently absorbed without being absorbed by the substrate cover (on the optical compensation sheet laminate side). ) And can be introduced into the liquid crystal display panel with high efficiency. As a result, a reflection sheet that has been conventionally provided separately on the LED mounting substrate is not necessary, and the number of members can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1

  FIG. 1 is an exploded perspective view illustrating a configuration example of a liquid crystal display device configured by using a backlight unit configured by the surface light source module of the present invention. In FIG. 1, a surface light source module 13 is configured by a heat radiation member 1, an LED 2, a substrate 3, a substrate cover 10, and a heat radiator (here, a lower housing is configured) 11. Although not shown, the heat conduction efficiency can be improved by inserting a heat dissipation sheet between the heat dissipation member 1 and the substrate 3. A diffusion plate 4, a diffusion sheet 5, a lens sheet (prism sheet) 6, and a diffusion sheet 7 are installed on the upper surface (light emitting surface) side of the surface light source module 13, and the front frame 8 is covered and integrated with the heat radiator 11. The backlight unit 19 is configured. And this backlight unit 19 is installed in the back surface of the liquid crystal display panel 9, and a liquid crystal display device is comprised.

  That is, in the backlight device 19 of the present embodiment, the surface light source is formed by arranging the substrates 3 in which a large number of LEDs 2 are linearly mounted on the bottom surface of the box-shaped heat radiating member 1 having an upper surface serving as a surface light emitting portion. To do. A substrate 3 on which a large number of LEDs 2 are mounted in a straight line may be referred to as an LED mounting substrate 3. A substrate cover 10 is arranged so as to cover a plurality of LED mounting substrates 3 arranged in a row, and a surface light source module 13 is formed. In this embodiment, a large number of LEDs 2 are mounted linearly on the three strips of the substrate. However, the present invention is not limited to this, and it is also possible to mount the LEDs grouped for each emission color.

  Above the substrate cover 10 constituting the surface light source module 13, various optical sheets (optical compensation sheet laminate) 18 for light diffusion and condensing composed of the diffusion plate 4, the diffusion sheet 5, the lens sheet 6, and the diffusion sheet 7. Place. A front frame 8 that is a housing cover that constitutes the upper housing is fitted into the heat radiating member 1 and is fixed integrally with a heat radiator 11 that constitutes the lower housing. Although not shown in the figure, the heat radiator 11 provided on the bottom lower surface side of the heat dissipating member 1 is provided with heat dissipating fins, heat pipes and the like as necessary.

  FIG. 2 is a perspective view for explaining a detailed configuration of the LED mounting substrate 3 in FIG. 1. Mounted on this LED mounting board 3 are a plurality of LEDs 2 that are preferably colored in blue, green, and red, respectively, arranged in a quantity ratio (1: 1: 1) for synthesis to a desired white chromaticity. It is. The electrodes of the respective LEDs 2 are connected to the power supply wiring on the LED mounting substrate 3 by Au wires. In the present embodiment, blue, green, and red three primary color LEDs are mounted on the substrate 3 in order and repeatedly in blue, green, and red. Then, a transparent resin lens 12 formed in a semi-cylindrical shape (may be semi-cylindrical or hemispherical) is covered so as to cover the LED 2.

  As a base material of the LED mounting substrate 3, a metal such as a high thermal conductivity aluminum-based or copper-based alloy, ceramics such as aluminum nitride or alumina, or the like is used. 2, D1 is the length of the lens 12 (longitudinal dimension of the LED mounting board 3), D2 is the width of the lens 12 (short side dimension of the LED mounting board 3), D3 is the longitudinal dimension of the LED mounting board 3, D4 indicates the dimension in the short-side direction of the LED mounting substrate 3.

  A reflective portion 21 is formed or surface-treated in the vicinity of the LED 2 mounting portion of the LED mounting substrate 3. This reflection part 21 can be comprised by gold plating, silver plating, aluminum vapor deposition, etc., for example. In addition to the metal film, the reflecting section 21 can also be formed by forming a so-called white film having high light reflection characteristics in the visible region, such as a resist film or a metal oxide film. In addition, as for the reflection part 21, it is desirable to form not only the mounting site | part vicinity of LED2 in the LED mounting board 3, but the whole upper surface of the LED mounting board 3. FIG.

  3 is a diagram for explaining a detailed configuration of the substrate cover 10 in FIG. 1. FIG. 3A is a top view of the substrate cover 10 as viewed from the front frame 8 side (an enlarged view of the main part). (b) is sectional drawing (longitudinal direction) along the AB line | wire of Fig.3 (a). FIG.3 (c) is sectional drawing (short direction) along CD of FIG.3 (a). 3, d1 is a length in the longitudinal direction between the upper ridges of the reflector (inclined surface) 24 facing the lens hole 22 of the substrate cover 10, d2 is a width of the longitudinal opening of the lens hole 22, and d3 is a substrate cover. 10, the length dimension in the short direction between the upper ridge lines of the reflector (inclined surface) 24 facing the lens hole 22, and d4 indicates the width dimension of the opening in the short direction of the lens hole 22.

  The substrate cover 10 may be, for example, a thin plate having thermal conductivity using a metal material such as aluminum or an alloy thereof, copper or an alloy thereof, or stainless steel, a thermosetting resin such as an epoxy resin, or a liquid crystal polymer. A thermoplastic resin such as the above may be used, but a flexible resin that can be bent with a relatively small force is desirable. The material for forming the substrate cover 10 is not limited to the above example.

  In the present embodiment, the diameter of the lens hole 42 penetratingly formed in the substrate cover 10 is formed so as to become narrower from the upper surface side toward the lower surface side. That is, in the longitudinal direction, the lower opening diameter d2 on the lower side of the substrate cover 10 is smaller than the upper opening diameter d1 on the upper side of the substrate cover 10 (d2 <d1). The lower opening diameter d2 is set to be not less than the lens length D1 of the lens 12 shown in FIG. 2 and less than the substrate length D3 (D1 ≦ d2 <D3).

  In the short direction of the lens hole 42, the lower opening diameter d4 on the lower side of the substrate cover 10 is smaller than the upper opening diameter d3 on the upper side of the substrate cover 10 (d4 <d3). The lower opening diameter d4 is set to be not less than the lens length D2 of the lens 12 shown in FIG. 2 and less than the substrate length D4 (D2 ≦ d4 <D4).

  In addition, on the back side of the substrate cover 10, that is, the surface in contact with the LED mounting substrate 3, an inner step 27 that accommodates edge portions of the respective sides of the LED mounting substrate 3 is formed. The longitudinal dimension W1 of the lens hole 42 of the inner step 27 is W1 ≦ D3, and the lateral dimension W2 is W2 ≦ D4. By making the height of the inner step 27 equivalent to or slightly lower than the thickness of the LED mounting substrate 3, the LED mounting substrate 3 can be held firmly.

  With such a configuration, the lens hole 22 of the substrate cover 10 is formed with an inner wall that expands from the lower portion (the LED mounting substrate 3 side) toward the upper portion (the light emitting side). In the present embodiment, a reflector is formed on the inner wall of the lens hole 22 or the surface is light-reflected to form a reflector 24 that is an inclined reflecting surface that functions as a reflecting member or a reflecting part. . That is, the substrate cover 10 having the reflector portion 24 has a reflector function for directing light emitted from the LEDs upward. The reflector portion 24 can be made of a metal film such as gold, silver, aluminum, or nickel.

  In addition to the metal film, the reflector section 24 can also be formed of a so-called white film having high light reflection characteristics in the visible region, such as a resist film or a metal oxide film. Further, when a metal plate is adopted as the substrate cover 10, the metal background exposed on the inner wall of the formed lens hole 22 can be functioned as the reflector portion 24 as it is or by polishing or the like. is there. The reflector portion 24 is preferably formed of a material having a light reflectance of 30% or more in the entire visible region.

  A surface layer 25 that functions as a reflective layer is formed on the upper surface of the substrate cover 10. The surface layer 25 has a characteristic of reflecting light in the visible region, and can be formed of the same material as that of the reflector portion 24, for example. At this time, the reflector portion 24 and the surface layer 25 can be simultaneously formed in the same process on the substrate cover 10 in which the lens hole 22 and the screw hole 23 are formed. Moreover, it is also possible to form the reflector part 24 and the surface layer 25 by different materials and different processes.

  FIG. 4 is an exploded perspective view for explaining the configuration of the light emitting module 13. The light emitting module 13 includes a plurality of LED mounting boards 3 on which a plurality of LEDs 2 are mounted, a heat dissipation sheet 14 and a lens 12 (not shown) that covers the LEDs 2 between the LED mounting board 3 and the heat dissipation member 1, a board A substrate cover 10 used for fixing 3 is provided. Furthermore, a plurality of screw holes 22 corresponding to the mounting positions of the screws 17 are formed through the heat radiating member 1.

  Further, the substrate cover 10 that functions as a positioning member, a fixing member, or an attachment member for the components of the surface light source module has a plurality of lens holes 22 corresponding to the attachment positions of the lenses 12, that is, the attachment positions of the LEDs 2 on the substrate 3. A plurality of screw holes 23 corresponding to the mounting positions of the screws 17 are formed to penetrate each other.

  Next, a method for manufacturing the light emitting module 13 will be described. First, a plurality of LED mounting boards 3, a heat radiation sheet 14, and a board cover 10 on which a plurality of LEDs 2 are mounted are prepared. Next, the lens 12 provided on the LED mounting substrate 3 is inserted into each lens hole 23 provided in the substrate cover 10. At this time, each lens 12 is inserted from the lower part of the substrate cover 10, that is, the side where the outer diameter of the lens hole 22 is narrow (the side where the surface layer 25 is not formed: the back side).

  At this time, the lens minor diameter D2 of the lens 12 is equal to or smaller than the lower opening diameter d4 of the lens hole 22, and the lens major diameter D1 is equal to or smaller than the lower opening major diameter d2 of the lens hole 42. Therefore, the lens 12 passes through the lens hole 22 from the lower part and protrudes to the upper part of the substrate cover 3. However, the short side (side in the short direction) dimension D4 of the LED mounting board 3 is larger than the lower opening short diameter d4 of the lens hole 22, and the long side (side in the longitudinal direction) dimension D3 of the LED mounting board 3 is Since it is larger than the lower opening major axis d2 of the lens hole 22, the lens 12 cannot pass through the lens hole 22 and is locked by the substrate cover 10. As a result, the LED mounting board 3 is held by the board cover 10.

  Then, the substrate cover 10 is pressed from the lower side by the heat radiating member 1. At this time, the heat radiating sheet 14 is sandwiched between the back surface of the LED mounting substrate 3 (between the heat radiating member 1) and the lens 12 provided on the upper surface of the LED mounting substrate 3 is disposed in each lens hole 42. Thereby, the LED mounting substrate 3 and the heat dissipation sheet 14 are sandwiched between the substrate cover 10 and the heat dissipation member 1. In this state, the LED mounting substrate 3 is fixed by further screwing the substrate cover 10 and the heat radiating member 1 directly into the screw holes 26 of the heat radiating member 1 using the screws 17.

  FIG. 5 is a diagram for explaining an optical path of light emitted from the LED 2 provided in the light emitting module 13. In the present embodiment, the chip of the LED 2 shown in FIG. 5 is one of the red LED that emits red, the green LED that emits green, and the blue LED that emits blue as described above. . Further, as can be seen from FIG. 5, when the lens 12 is fixed on the LED mounting substrate 3 with the substrate cover 10, the upper end position of the reflector portion 24 provided on the substrate cover 10 is lower than the upper end of the LED 2. To position.

  Next, the irradiation of light by the surface light source module 13 produced in this way will be described in detail with reference to FIG. 1 together with FIG. When a predetermined current flows through the LED 2, the LED 2 emits light. And the light radiate | emitted from LED2 spreads in each direction as shown by the arrow line. Of the emitted light, for example, the light irradiated obliquely upward from the LED 2 passes through the lens 12 and then is directly applied to the diffusion plate 4 described with reference to FIG.

  On the other hand, of the irradiated light, for example, light irradiated in a direction substantially parallel to the plane of the substrate 3 passes through the lens 12 and then enters the reflector portion 24 provided on the substrate cover 10. At this time, as shown in FIG. 3, the reflector portion 24 faces obliquely upward because the lens hole 22 is formed in a positive taper shape. The light incident on the reflector 24 is directed upward, that is, in the direction of irradiating the diffusion plate 4 after being reflected by the reflector 24.

  Further, among the light emitted from these LEDs 2, for example, the light irradiated obliquely downward in FIG. 5 enters the surface of the substrate 3. Here, in the present embodiment, since the reflection portion 21 is formed corresponding to the attachment site of the LED 2 (see FIG. 2), the light incident on the reflection portion 21 on the substrate 3 is reflected by the reflection portion 21. Then, it is directed to irradiate the upper part, that is, the diffusion plate 4.

  In addition, much of the light irradiated on the diffusion plate 4 in this way passes through the diffusion plate 4 while being diffused, and is irradiated toward the front frame 8 side. However, a part of the light is reflected by the diffusion plate 4 and returns to the light emitting module 13 side. At this time, a surface layer 25 having a reflection characteristic with respect to visible light is formed on the surface of the substrate cover 10, and the light reflected from the diffusion plate 4 is reflected by the surface layer 25 and again enters the diffusion plate 4. It will be irradiated towards.

  As described above, in this embodiment, the substrate cover 10 is used to position and fix each substrate 3 on the heat dissipation substrate 1, so that the substrate replacement work for correcting the luminance variation is performed. Easy. In the present embodiment, a plurality of lens holes 22 are provided in the substrate cover 10, and the reflector portion 24 is formed on the inner wall of the lens holes 22. Furthermore, the reflector 24 is formed so as to face obliquely upward by making the inner peripheral edge of the lens hole 22 into a positive taper shape that opens upward. As a result, the light emitted from the LED 2 is transmitted through the lens 12 and then reflected by the reflector unit 24, and the reflected light is irradiated toward the liquid crystal panel 9 through the diffusion plate 4. Therefore, the light irradiation efficiency by the backlight device 19 can be improved.

  Moreover, in this Embodiment, the lower end position of the reflector part 24 was made lower than LED2, so that the light emitted from LED2 and emitted obliquely downward could be reflected upward. Thereby, the light irradiation efficiency of each LED 2 and thus the backlight device 19 can be further increased. Furthermore, in the present embodiment, since the surface layer 25 having a high reflectance is provided on the upper surface of the substrate cover 10, it becomes possible to re-reflect the light reflected from the diffusion plate 4 after coming out of the LED, The light irradiation efficiency of each LED 2 and thus the backlight device 19 can be further increased.

  In the present embodiment, the reflector portion 24 is formed directly on the substrate cover 10 itself. However, the present invention is not limited to this, and the reflector portion 24 is attached to the substrate cover 10 by attaching the member on which the reflector portion 24 is formed. You may make it comprise.

Embodiment 2

  Hereinafter, the backlight unit as Embodiment 2 of the present invention will be described. FIG. 6 is a cross-sectional view showing a configuration of an edge light system which is another example of the backlight unit for explaining the second embodiment of the present invention. The backlight unit of the edge light system includes an LED 2, a substrate 3, a substrate cover 10, a light guide plate 31, a diffusion plate 32, a reflection plate 33, a heat radiating member 1, and a frame 30. The light emitted from the LED 2 as the light source is incident from the side wall of the light guide plate 31, the light from the LED 2 is guided using the light guide plate 31, the optical path is changed in the direction of the diffusion plate 32 in the course of propagation, and the diffusion plate 4 A thin surface light source is realized by diffusing light while controlling uniformity and directivity. The reflecting plate 33 reflects the light leaking from the back surface of the light guide plate 31 and returns it into the light guide plate, thereby improving the light utilization efficiency.

  In addition, description of the optical control circuit part etc. which perform optical control of the brightness | luminance of the some mounted LED element, a color gamut, a color tone, etc. is abbreviate | omitted here. In FIG. 6, the light source is provided on one side wall of the light guide plate 31, but the light source is provided also on the side wall opposite to the one side wall of the light guide plate 31, on the three side walls of the light guide plate 31, or on all side walls. Thus, the required luminance can be realized in accordance with the size of the applied liquid crystal display panel.

  FIG. 7 is a cross-sectional view of an essential part for explaining the configuration of the portion of the substrate cover 10 in the edge light system according to Embodiment 2 of the present invention. In FIG. 7, the substrate 3 is fixed and held by being sandwiched between the heat dissipation member 1 and the substrate cover 10. The substrate cover 10 is provided with a notch 16 that can be easily positioned by fitting the side wall of the light incident portion of the light guide plate 52. As described in the first embodiment, since the substrate cover 10 positions the lens 12 provided on the substrate 3, it is possible to correctly position the light guide plate 31 on the straight line of the lens 12. It becomes. Therefore, the light emitted from the lens 12 can be efficiently introduced into the light guide plate 52, the use efficiency of the backlight light obtained through the optical compensation sheet Louis 18 and illuminating the display panel 9 can be improved, and a high-luminance video display can be obtained. Can do.

It is an expansion | deployment perspective view explaining the structural example of the liquid crystal display device comprised using the backlight unit comprised with the surface light source module of this invention. It is a perspective view for demonstrating the detailed structure of the LED mounting board in FIG. It is a figure for demonstrating the detailed structure of the board | substrate cover in FIG. It is an expansion | deployment perspective view for demonstrating the structure of a light emitting module. It is a figure for demonstrating the optical path of the light irradiated from LED provided in the light emitting module. It is sectional drawing which shows the structure of the edge light system which is another example of the backlight apparatus explaining Embodiment 2 of this invention. It is principal part sectional drawing for demonstrating the structure of the part of the board | substrate cover in the edge light system in Embodiment 2 of this invention. It is a schematic diagram explaining the structural example of the surface light source module of the conventional direct type backlight unit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat dissipation member, 2 ... LED, 3 ... Board | substrate (LED mounting board), 4 ... Diffusion plate, 5, 7 ... Diffusion sheet, 6 ... Lens sheet, ... Front frame, 9 ... Liquid crystal display panel, 10 ... Substrate cover, 11 ... Thermal radiator (housing), 12 ... Lens, 13 ... Light emitting module, 14 ... Heat dissipation sheet , 15 ... reflection sheet, 16 ... notch, 17 ... screw, 18 ... optical compensation sheet, 19 ... backlight unit, 21 ... reflection processing section, 22 ... lens Hole, 23 ... Screw hole, 24 ... Reflector part, 25 ... Surface layer, 26 ... Screw hole, 31 ... Light guide plate, 32 ... Diffuser plate, 33 ... Reflector plate .

Claims (12)

A heat dissipating member having a flat surface;
A surface light source module comprising a plurality of solid-state light-emitting element mounting substrates mounted with a plurality of solid-state light-emitting elements and disposed on the flat surface of the heat dissipation member,
The solid-state light-emitting element mounting substrate has a semi-cylindrical lens that covers the plurality of solid-state light-emitting elements and directs light emitted from the solid-state light-emitting element to the side opposite to the solid-state light-emitting element mounting substrate.
A plurality of lens holes having a major axis and a minor axis corresponding to the long side and the short side of the planar shape of the lens are formed at each mounting position of the lens, and the lens is inserted into each of the plurality of lens holes. And having a substrate cover that covers the top surface of the plurality of solid state light emitting device mounting substrates,
The substrate cover has a light reflecting member on an inner wall surface of the plurality of lens holes and a surface opposite to the solid light emitting element mounting substrate,
A surface light source module, wherein the solid light emitting element mounting substrate is fixed to the heat dissipating member by sandwiching the plurality of solid light emitting element mounting substrates between the substrate cover and the heat dissipating member. In claim 1,
The plurality of lens holes formed in the substrate cover are larger than the maximum major axis of the lens at any major axis, and are larger than the maximum minor axis of the lens at any minor axis of the plurality of holes. A surface light source module. In claim 1,
Inner walls of the plurality of lens holes formed in the substrate cover are positive tapered surfaces,
The surface light source module, wherein the light reflecting member is disposed on the positive tapered surface formed on the inner wall. In claim 1,
With the solid light emitting element mounting substrate attached to the heat dissipation member with the substrate cover, the upper end of the positive taper surface is fixed to be equal to or less than the height of the lens mounted on the solid light emitting element mounting substrate. A characteristic surface light source module. In claim 1,
A surface light source module comprising a heat radiation sheet between the solid light emitting element mounting substrate and the heat radiation member. A backlight unit having a surface light source module and an optical compensation sheet laminate disposed on a light exit surface of the surface light source module,
The surface light source module includes a heat dissipating member having a flat surface, and a plurality of solid light emitting element mounting substrates mounted on the flat surface of the heat dissipating member by mounting a plurality of solid light emitting elements.
The solid-state light-emitting element mounting substrate has a semi-cylindrical lens that covers the plurality of solid-state light-emitting elements and directs light emitted from the solid-state light-emitting element to the side opposite to the solid-state light-emitting element mounting substrate.
A plurality of lens holes having a major axis and a minor axis corresponding to the long side and the short side of the planar shape of the lens are formed at each mounting position of the lens, and the lens is inserted into each of the plurality of lens holes. And having a substrate cover that covers the top surface of the plurality of solid state light emitting device mounting substrates,
The substrate cover has a light reflecting member on an inner wall surface of the plurality of lens holes and a surface opposite to the solid light emitting element mounting substrate,
By sandwiching the plurality of solid state light emitting element mounting substrates between the substrate cover and the heat dissipating member, the solid state light emitting element mounting substrate is fixed integrally with the heat dissipating member,
The optical compensation sheet laminate includes a diffusion plate that covers the substrate cover, and a diffusion sheet and a lens sheet stacked on the diffusion plate. A backlight unit having a surface light source module provided with a light guide plate, and an optical compensation sheet laminate disposed on a light exit surface of the surface light source module,
The surface light source module includes a heat dissipating member having a flat surface, and a plurality of solid light emitting element mounting substrates mounted on the flat surface of the heat dissipating member by mounting a plurality of solid light emitting elements.
The solid-state light-emitting element mounting substrate includes a semi-cylindrical lens that covers the plurality of solid-state light-emitting elements and directs light emitted from the solid-state light-emitting elements toward a side wall of the light guide plate,
A plurality of lens holes having a major axis and a minor axis corresponding to the long side and the short side of the planar shape of the lens are formed at each mounting position of the lens, and the lens is inserted into each of the plurality of lens holes. And having a substrate cover that covers the upper surface of the plurality of solid state light emitting device mounting substrates,
The substrate cover has a light reflecting member on an inner wall surface of the plurality of lens holes and a surface opposite to the solid light emitting element mounting substrate,
By sandwiching the plurality of solid state light emitting element mounting substrates between the substrate cover and the heat dissipating member, the solid state light emitting element mounting substrate is fixed integrally with the heat dissipating member,
The light guide plate is made of a transparent plate, has a light diffusion plate on the light exit surface of the transparent plate, and has a reflector on the opposite surface of the light exit surface,
It is configured by attaching the light emitting surface of the substrate cover to the side wall of the light guide plate,
The optical compensation sheet laminate includes a diffusion plate that covers the substrate cover, and a diffusion sheet and a lens sheet stacked on the diffusion plate. In claim 6 or 7,
The plurality of lens holes formed in the substrate cover are larger than the maximum major axis of the lens at any major axis, and are larger than the maximum minor axis of the lens at any minor axis of the plurality of holes. Backlight unit characterized by In claim 6 or 7,
Inner walls of the plurality of lens holes formed in the substrate cover are positive tapered surfaces,
The backlight unit, wherein the light reflecting member is disposed on the positive tapered surface formed on the inner wall. In claim 6 or 7,
With the solid light emitting element mounting substrate attached to the heat dissipation member with the substrate cover, the upper end of the positive taper surface is fixed to be equal to or less than the height of the lens mounted on the solid light emitting element mounting substrate. Characteristic backlight unit. In claim 6 or 7,
A backlight unit comprising a heat dissipation sheet between the solid light emitting element mounting substrate and the heat dissipation member. A liquid crystal display device having a liquid crystal display panel and a backlight unit that illuminates the liquid crystal display panel in a planar shape from the back,
The liquid crystal display device according to claim 6, wherein the backlight unit has the configuration according to claim 6.