JP4430585B2 - Surface light source device - Google Patents

Description

  The present invention relates to a surface light source device, and more particularly to a surface light source device that mixes light from a plurality of light emitting diodes that emit light of different wavelengths.

  A surface light source device using a light emitting diode (LED) is known as a surface light source device for illuminating a display panel such as a liquid crystal panel. As the surface light source device using light emitting diodes, there is an RGB-LED surface light source device that uses a set of three types of light emitting diodes that emit monochromatic light of red (R), green (G), and blue (B). . In such an RGB-LED surface light source device, white light is produced by mixing monochromatic light emitted from three types of light emitting diodes that emit R, G, and B monochromatic light. To be precise, the LED has a wavelength distribution of several tens nm to several hundreds nm centered on a certain wavelength, but is described here as monochromatic light for convenience.

  In the RGB-LED surface light source device, white light is generated by mixing three types of single-color light, so that a sufficient mixing distance is secured from the light-emitting diode that generates the single-color light so that the single-color light is sufficiently mixed. There is a need to. That is, white light with no color unevenness is formed by taking a sufficient mixing distance from a light emitting diode that generates monochromatic light.

  In addition, the RGB-LED surface light source device includes an edge light system in which a high-intensity light-emitting diode lamp is disposed facing the end face of the light guide plate, and a direct-in method in which a high-intensity light-emitting diode lamp is disposed directly under the diffusion plate There is. In the edge light system, a light-emitting diode lamp array in which light-emitting diode lamps are arranged is arranged so as to face the end face of the light guide plate, and light from the light-emitting diode lamp is made incident on the end face of the light guide plate. In the direct method, several rows of light emitting diode lamps are arranged directly below the diffusion plate on the back surface of the display panel, and light is diffused by the diffusion plate, thereby obtaining uniform white light.

  In this specification, the PN junction semiconductor itself is called a light-emitting diode chip, and the light-emitting diode chip is placed on a substrate (heat sink), wired with a lead frame with a lead wire, and sealed with resin. A light-emitting diode module is called a light-emitting diode module, and a light-emitting diode lamp is mounted on a light-emitting diode module to make it easy to enter a light guide plate. A plurality of light emitting diode chips mounted on a single substrate, wired with lead wires between the lead frames, and sealed with resin is called a light emitting diode array module.

  On the other hand, white light emitting diodes may be used in small displays such as mobile phones and PDA displays. In such a small edge light type display, a surface mounted (SMD) type white light emitting diode module is mounted on a flexible substrate corresponding to the length of the end face of the light guide plate at a predetermined interval. A light source for illumination is configured by causing the emitted light to enter the light guide plate.

  On the other hand, surface light sources for lighting such as large monitors require a surface light source device with high brightness and high color rendering in order to increase the display area and reproduce realistic images. Light emitting diode lamps are often used. In such a surface light source device, R (red), G (green), and B (blue) light emitting diode lamps that can be driven with a large current of about 100 to 500 mA and have different emission wavelengths are used. These light-emitting diode lamps have an enhanced chip cooling structure to suppress an increase in junction temperature when driven with a large current. Further, in order to increase the incident efficiency of light emitted from the light emitting diode chip to the light guide plate, a light emitting diode lamp in which a lens is formed on a light emitting diode module sealed with resin is used. Usually, a silicone resin is injected and cured on a light-emitting diode chip to form a light-emitting diode module, which is then placed in an epoxy resin in a lens-shaped mold and cured to produce a light-emitting diode lamp having a lens. The Therefore, this type of light-emitting diode lamp has a size of several mm to 10 mm.

  JP-A-2003-8081 (Patent Document 1), JP-A-2003-8068 (Patent Document 2), and JP-A-2004-133391 (Patent Document 3) use such a light-emitting diode lamp. A surface light source device is described.

JP 2003-8081 A JP 2003-8068 A JP 2004-133391 A

  However, when individual RGB light-emitting diode lamps are used, white light is obtained by mixing (color mixing) light that can be regarded as RGB three types of monochromatic light, so that a sufficient mixing distance for mixing monochromatic light is provided. Must be secured. Therefore, there is a problem that the size and thickness of the periphery (frame) of a display surface such as a display increase.

  On the other hand, white light emitting diode lamps having high color rendering properties have recently been developed by improving phosphors of light emitting diode modules. When such a light emitting diode lamp is used, it is not necessary to secure a mixing distance, but the luminous efficiency is not sufficient and the luminance is insufficient. In addition, the surface light source device using such a white light emitting diode lamp is not as good as the surface light source device using individual light emitting diode lamps for RGB in the color reproduction range.

  In addition, in a surface light source device for a large-sized liquid crystal television, a direct system in which RGB individual light-emitting diode lamps are arranged on the back side of the display surface is employed. In such a surface light source device, linear light sources in which RGB individual light-emitting diode lamps are arranged one-dimensionally immediately below a diffusion plate disposed on the back side of the display surface are arranged in a plurality of rows at a predetermined interval. The light from the light source is mixed in space and diffused by a diffusion plate to achieve uniformity. In this direct system, it is necessary to dispose the light-emitting diode lamp rearward from the diffuser plate or the like in order to sufficiently perform mixing, and as a result, there is a problem that the thickness of the surface light source device is increased.

  In addition, the surface light source devices described in Japanese Patent Application Laid-Open Nos. 2003-8081, 2003-8068, and 2004-133391 use light emitting diode lamps that emit light in the entire circumferential direction. Attempts have been made to shorten the mixing distance. This surface light source device uses RGB individual light emitting diode lamps that emit light in a circumferential direction parallel to the display surface of a display or the like, and diffuses and reflects the light emitted to the opposite side of the light guide plate with a reflector or the like. The light of each color is mixed and incident on the light guide plate.

FIG. 12 is a side sectional view showing an example of the surface light source device having such a structure, and FIG. 13 is a plan side sectional view.
As shown in FIGS. 12 and 13, the surface light source device 130 guides light emitted from the light emitting diode lamps 102, a plurality of light emitting diode lamps 102, a substrate 104 on which the light emitting diode lamps 102 are arranged in a row. And a light guide plate 106. Furthermore, the surface light source device 100 is disposed on the back side of the light guide plate 106, a diffusion film 108 that diffuses and deflects light emitted from the light guide plate 106, a prism sheet 110 disposed on the front surface of the diffusion film 108, and the light guide plate 106. And a diffuse reflection plate 112. Further, the surface light source device 100 includes a reflector 114 that reflects light emitted upward and laterally from the light-emitting diode lamp 102. Further, white dot printing 116 is applied to the back surface of the light guide plate 106, and a mixing layer 118 is attached to the end surface of the side surface. Furthermore, heat radiation fins 120 are attached to the back side of the substrate 104 via heat radiation sheets.

  The light emitting diode lamps 102 include a predetermined number of light emitting diode lamps that emit red, green, and blue monochromatic light, and are disposed over the entire length of both end faces of the light guide plate at predetermined intervals. The light emitting diode lamp 102 is configured to emit light over the entire circumference in a direction parallel to the light guide plate 106.

  In the surface light source device having such a structure, the total length between both end faces of the light guide plate 106 on which light is incident is 300 mm, the thickness is 6 mm, the distance from the center of the light-emitting diode lamp 102 to the light guide plate 106 is 20 mm, and light emission When the distance from the center of the diode lamp to the side reflector 114 is 10 mm, the effective width in which the light guide plate 106 can be used as a uniform white light surface light source is about 100 mm. That is, in the surface light source device having such a structure, the mixing of the light of each color in the section of about 120 mm from the center of the light emitting diode lamp is insufficient, and the color band appears in those sections, and the white light without unevenness is generated. Can't get.

  Further, in the surface light source device having such a structure, there is a problem that much of the light emitted to the opposite side of the light guide plate is reflected and attenuated many times by the reflector on the lens surface and the opposite side of the light guide plate. . Further, from the gap between the light emitting diode lamps, there is a problem that light from a light emitting diode lamp of a specific color is incident on the light guide plate, so that a color band is likely to occur and color unevenness is likely to occur.

  On the other hand, in Japanese Patent Application Laid-Open Nos. 2003-8081, 2003-8068, and 2004-133391, surface light source devices in which light-emitting diode lamps are disposed in insertion holes provided in a light guide plate are also disclosed. Are listed. In this surface light source device, a penetrating insertion hole for inserting a light emitting diode lamp is provided near the end of the light guide plate. The inner diameter of the insertion hole is slightly larger than each light emitting diode lamp to be inserted, and light emitted from the inserted light emitting diode lamp to the entire circumference enters the light guide plate.

FIG. 14 is a side sectional view showing an example of the surface light source device having such a structure, and FIG. 15 is a plan side sectional view.
As shown in FIGS. 14 and 15, the surface light source device 150 includes a plurality of light emitting diode lamps 102, a substrate 104, a light guide plate 152, a diffusion film 108, a prism sheet 110, and a diffuse reflection plate 112. Have. The surface light source device 150 includes a reflector 114, white dot printing 116 is applied to the back surface of the light guide plate 152, and heat radiating fins 120 are attached to the back surface side of the substrate 104.

  Near the end of the light guide plate 152, a plurality of insertion holes 152a through which the respective light emitting diode lamps 102 are inserted are provided in a line. Furthermore, since the light emitting diode lamp 102 emits light over the entire circumference in a direction parallel to the light guide plate 152, most of the light emitted from the light emitting diode lamp 102 enters the light guide plate 152. In this example, the insertion holes 152a aligned in a line are formed at a center with a pitch of 10 mm, and the diameter of the light-emitting diode lamp 102 inserted into the insertion holes 152a is about 7 mm. When the diameter is 8 mm, the interval (gap) between the insertion holes 152a is 2 mm.

  In the surface light source device having such a structure, when the total length between the end faces having the reflectors on both sides of the light guide plate 152 is 360 mm, the thickness is 6 mm, and the distance from the center of the light emitting diode lamp to the side reflector 114 is 15 mm, The effective width in which the light guide plate 152 can be used as a uniform white light surface light source is about 150 mm. That is, in the surface light source device having such a structure, the mixing of the light of each color in the section of about 90 mm from the center of the light emitting diode lamp is insufficient, and the band of the color appears in those sections, and the uneven white light is generated. Can't get.

  That is, in the structure such as the surface light source device 150, color mixing is promoted in the light guide plate 152, and the mixing distance can be shortened. However, the gap between the insertion holes 152a is 1.5 mm or less in the above example. In this case, the number of reflections of the light incident on the light guide plate 152 is very large, and the incident light is attenuated.

  Therefore, an object of the present invention is to provide a surface light source device that can obtain white light having no color unevenness at a short mixing distance and can efficiently emit light emitted from a light emitting diode. Yes.

  In the surface light source device of the present invention, two or more types of light emitting diode chips having different wavelengths are arranged on one substrate, each light emitting diode chip is sealed with a resin, and is closely attached to the back side of the light guide plate. One or more light emitting diode array modules, and light deflecting recesses are formed in alignment on the back side at positions corresponding to the respective light emitting diode chips of the light emitting diode array module. A light guide plate having a plurality of substantially conical grooves formed at positions corresponding to each of the light guide plates, and an end surface of the light guide plate, and a reflector mounted on the row of the substantially conical grooves. It is said.

  In the present invention configured as above, the plurality of light emitting diode chips each emit light of a predetermined wavelength. The light emitted from each light emitting diode chip is deflected and incident into the light guide plate through the sealing resin and the wall surface of the light deflection recess of the light guide plate. Part of the light incident on the light guide plate is reflected by conical grooves provided corresponding to the positions of the light deflection recesses, and propagates in all directions within the light guide plate. In addition, the reflector attached at a predetermined position of the light guide plate diffuses and reflects the light reaching the light guide and directs it toward the center of the light guide plate. Light of each wavelength incident on the light guide plate is mixed in the light guide plate and emitted from the light guide plate in a predetermined direction. That is, in addition to efficiently making the light of the light emitting diode module incident on the light guide plate, it is possible to effectively mix the light of each wavelength with a short mixing distance, and the white light with less color unevenness of the surface light source device, The light can be emitted in a wide area.

  In the surface light source device of the present invention, two or more types of light emitting diode chips having different wavelengths are arranged on one substrate, each light emitting diode chip is sealed with resin, and is closely arranged on the back side of the light guide plate. One or more light emitting diode array modules, and light deflecting recesses are formed in alignment on the back side at positions corresponding to the respective light emitting diode chips of the light emitting diode array module. A light guide plate formed with elongated grooves having a substantially V-shaped cross section formed so as to extend in parallel to the rows of the light deflection recesses at positions corresponding to the rows of the light deflection plate, an end surface of the light guide plate, and the substantially V-shaped cross section of the light guide plate. And a reflector mounted on the elongated groove.

  In the present invention configured as above, the plurality of light emitting diode chips each emit light of a predetermined wavelength. The light emitted from each light emitting diode chip is deflected and incident into the light guide plate through the sealing resin and the wall surface of the light deflection recess of the light guide plate. Part of the light incident on the light guide plate is reflected by an elongated groove having a V-shaped cross section formed so as to extend in parallel with the row of light deflection recesses, and propagates in all directions in the light guide plate. In addition, the reflector attached at a predetermined position of the light guide plate diffuses and reflects the light reaching the light guide and directs it toward the center of the light guide plate. Light of each wavelength incident on the light guide plate is mixed in the light guide plate and emitted from the light guide plate in a predetermined direction. That is, in addition to efficiently making the light of the light emitting diode module incident on the light guide plate, it is possible to effectively mix the light of each wavelength with a short mixing distance, and the white light with less color unevenness of the surface light source device, The light can be emitted in a wide area.

  In the surface light source device of the present invention, two or more types of light emitting diode chips having different wavelengths are arranged on one substrate, each light emitting diode chip is sealed with resin, and is closely arranged on the back side of the light guide plate. One or more light emitting diode array modules, and a light guide plate in which light deflection recesses are formed in alignment on both the front side and the back side at positions corresponding to the respective light emitting diode chips of the light emitting diode array module And a reflector attached to the end face of the light guide plate.

  In the present invention configured as above, the plurality of light emitting diode chips each emit light of a predetermined wavelength. The light emitted from each light emitting diode chip is deflected and incident into the light guide plate through the sealing resin and the wall surface of the light deflection recess of the light guide plate. A part of the light incident on the light guide plate is reflected by the conical groove provided corresponding to the position of the light deflection recess on the facing side or the deflection recess on the facing side, and propagates in all directions in the light guide plate. Of course, the light deflection recesses may be at the same position or may be shifted. The reflector attached at a predetermined position of the light guide plate diffuses and reflects the light reaching the light guide and directs it toward the center of the light guide plate. Light of each wavelength incident on the light guide plate is mixed in the light guide plate and emitted from the light guide plate in a predetermined direction. That is, the light of the light emitting diode module can be efficiently incident on the light guide plate, and the light emitting diode chips of each wavelength can be spaced by using both surfaces of the light guide plate, and the surface light source device has less color unevenness. White light can be emitted in a wide area.

  In the present invention, in the case of a relatively large light guide plate, a plurality of rows of light deflection recesses, generally conical grooves or elongated grooves having a substantially V-shaped cross section are arranged on both ends or the center of the light guide plate. According to the present invention configured as above, the amount of light can be appropriately increased according to application.

In the present invention, it is preferable to arrange the light emitting diode array modules in a plurality of rows.
In the present invention, preferably, a recess is formed in the substrate of the light emitting diode array module, and a light emitting diode chip is mounted on the bottom surface thereof.
In the present invention, preferably, the light emitting diode array module has a plurality of light emitting diode chip assemblies dispersedly arranged, and the light deflection recesses or the substantially conical shapes are arranged at positions corresponding to the respective assemblies. A light guide plate having grooves is formed.

  According to the present invention configured as described above, light is reflected by the side wall of the concave portion of the substrate, and most of the light from the light emitting diode array module is emitted in the thickness direction of the light guide plate, and is substantially conical groove or substantially V-shaped. The light is reflected from the elongated groove in the cross section and reflected in the surface direction of the light guide plate. That is, the light from the light emitting diode module can be efficiently incident on the light guide plate.

In the present invention, preferably, in the light-emitting diode array module, a collection of light-emitting diode chips is dispersedly arranged, and a light deflection plate or a substantially conical groove is formed at a position corresponding to each of the collection. Have
According to the present invention configured as described above, by mounting a chip with a small area that is efficient with respect to the supplied power at present, it is possible to realize high luminance with the same power and power saving with the same luminance. A method of forming an aggregate with the same chip and a method of forming an aggregate with light-emitting diode chips having two or more different wavelengths are conceivable. In the former case, chips with uniform performance can be arranged, and there is a possibility that chips are connected in parallel. The latter can emit white light having no color unevenness at a very short mixing distance in a wide area.

  According to the surface light source device of the present invention, white light having no color unevenness can be obtained at a short mixing distance, and the light emitted from the light emitting diode can be emitted efficiently.

Next, a surface light source device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, a surface light source device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an enlarged side sectional view showing the vicinity of an end portion of the surface light source device according to the first embodiment of the present invention, and FIG. 2 is a plan side sectional view showing the vicinity of the end portion. FIG. 3 is an enlarged cross-sectional view of a portion to which the light emitting diode module is attached in the surface light source device according to the present embodiment.

  As shown in FIGS. 1 to 3, a surface light source device 1 according to a first embodiment of the present invention includes a plurality of light emitting diode modules 2, a substrate 4 on which the light emitting diode modules 2 are arranged in a row, and a light emitting diode module. 2 has a light guide plate 6 that guides the emitted light. Further, the surface light source device 1 of the present embodiment includes a diffusion film 8 that diffuses and deflects light emitted from the light guide plate 6, a prism sheet 10 disposed on the front surface of the diffusion film 8, and the light guide plate 6. And a diffuse reflection plate 12 disposed on the back side. Moreover, the surface light source device 1 of this embodiment has the reflector 14 which reflects the light radiate | emitted above and the side of the light emitting diode module 2. FIG. In addition, heat radiating fins 18 are attached to the back side of the substrate 4 via heat radiating sheets (not shown).

  The light emitting diode module 2 includes three types of light emitting diode modules that emit light that can be regarded as monochromatic light of red (R), green (G), and blue (B), respectively. Each light emitting diode module 2 is for driving a large current. In the present embodiment, a current of about 300 mA is passed through the light emitting diode module 2. Further, the number of light emitting diode modules 2 of each color is configured to be R: G: B = 1: 2: 1. Moreover, in this embodiment, the diameter of the light emitting diode module 2 is about 5 mm. The detailed configuration of the light emitting diode module 2 will be described later with reference to FIG.

  A plurality of light emitting diode modules 2 are mounted on the substrate 4 in a line at a pitch of 10 mm. The substrate 4 on which the plurality of light emitting diode modules 2 are arranged and arranged constitutes a light emitting diode module array. In this light emitting diode module array, red, green and blue light emitting diode modules are arranged in a predetermined order. In the present embodiment, an aluminum substrate with good heat dissipation is used as the substrate 4 in order to efficiently dissipate the heat generated by each light emitting diode module 2.

  The radiating fins 18 are attached to the back side of the substrate 4 via a radiating sheet (not shown) so that heat conducted from the light emitting diode module 2 to the substrate 4 is efficiently conducted to the radiating fins 18. It is configured. Therefore, the heat generated by each light emitting diode module 2 is dissipated to the outside air through the substrate 4, the heat radiating sheet (not shown), and the heat radiating fins 18.

  The light guide plate 6 is a transparent resin rectangular plate having a length of about 380 mm and a width of about 420 mm, and has a thickness of about 6 mm. A plurality of light-emitting diode insertion recesses 20 for receiving the respective light-emitting diode modules 2 are formed on both side edges of the light guide plate 6 on the back side in the horizontal direction. The plurality of recesses 20 are aligned on a straight line parallel to the vertical side of the light guide plate 6 and are formed at equal intervals over the entire side. Each recess 20 is a cylindrical depression having a diameter of about 5.5 mm and a depth of about 1.5 mm, and is arranged so that the distance between the centers is about 10 mm. Therefore, the minimum distance (gap) between the wall surface of a certain recess 20 and the wall surface of the adjacent recess 20 is about 4.5 mm. In the present embodiment, the light guide plate 6 is made of a transparent polymethyl methacrylate resin (PMMA). Further, the inner wall surface of the recess 20 may be subjected to mat processing or prism processing so that light incident on the light guide plate 6 from each light emitting diode module 2 is easily diffused.

  A plurality of conical grooves 22 are formed at positions on the front side of the light guide plate 6 corresponding to the recesses 20. Each groove 22 is a recess that extends conically from one point on the bottom toward the surface of the light guide plate 6, and is formed one by one corresponding to each recess 20. The conical apex angle of each groove 22 is about 90 °, the diameter of the groove 22 on the surface of the light guide plate 6 is about 5 mm, and the depth of the groove 22 is about 2.5 mm. Each groove 22 is arranged such that the center of each cylindrical recess 20 and the center of each groove 22 are aligned.

Further, white dot printing 16 is applied to the back side of the light guide plate 6. The dot printing 16 diffuses and reflects the light reaching the back surface of the light guide plate 6 so that the luminance of the light emitted from the front surface of the light guide plate 6 is uniform.
The diffusion film 8 is a rectangular thin sheet-like member disposed on the front surface side of the light guide plate 6 substantially in parallel with the light guide plate 6. The diffusion film 8 is configured to diffuse and deflect the light emitted from each light emitting diode module 2 and guided by the light guide plate 6 and emitted.

The prism sheet 10 is a rectangular thin sheet-like member disposed on the front surface side of the diffusion film 8 substantially in parallel with the light guide plate 6. On the front side of this prism sheet 10 (opposite side of the light guide plate 6), a large number of elongated prisms having an isosceles triangular cross section are formed side by side without any gaps, and the light from the diffusion film 8 is directed in the normal direction (see FIG. 1).
The diffuse reflection plate 12 is a rectangular thin sheet-like member disposed on the back side of the light guide plate 6 and substantially parallel to the light guide plate 6. The diffuse reflection plate 12 is configured to diffuse and reflect the light emitted from each light emitting diode module 2, guided by the light guide plate 6, and emitted to the back side of the light guide plate 6.

  The reflector 14 is attached so as to cover the end surface of the side where the plurality of recesses 20 of the light guide plate 6 are formed and the plurality of grooves 22 on the front surface of the light guide plate 6. The reflector 14 is configured to reflect the light guided by the light guide plate 6 and reaching the surface portion of the light guide plate 6 to which the reflector 14 is attached. Thereby, the light reflected by the reflector 14 is directed again into the light guide plate 6 and used as light emitted from the surface light source device 1.

  Next, a detailed configuration of the light emitting diode module 2 will be described with reference to FIG. As shown in FIG. 3, the light-emitting diode module 2 includes a light-emitting diode chip 24 that is a PN junction semiconductor, a heat sink 26 to which the light-emitting diode chip 24 is attached, and 2 for supplying power to the light-emitting diode module 2. Two lead frames 28. Furthermore, the light emitting diode module 2 includes two lead wires 30 that connect the anode and cathode of the light emitting diode chip 24 to each lead frame 28, and a resin 32 that seals the light emitting diode chip 24 and the lead wire 30, respectively. Have As described above, the diameter of the light emitting diode module 2 used in the present embodiment is about 5 mm. Thus, since the light emitting diode module 2 is not provided with a lens or the like, the large current type light emitting diode can be configured to be smaller than the light emitting diode lamp.

  The light generated in the light emitting diode chip 24 configured as described above is transmitted directly through the sealing resin 32 and directly emitted. The heat generated by the light emitting diode chip 24 is conducted to the substrate 4 through the heat sink 26 and is dissipated. In addition, since no lens or the like is provided around the resin 32, the light generated by the light emitting diode chip 24 is emitted so as to spread almost uniformly in the hemispherical space around the light emitting diode module 2. .

Next, with reference to FIG.1 and FIG.2, the effect | action of the surface light source device 1 by 1st Embodiment of this invention is demonstrated.
First, when a power switch (not shown) of the surface light source device 1 of this embodiment is turned on, a current flows through each light emitting diode module 2, and red, green, and blue monochromatic light is emitted from each light emitting diode module 2. Are emitted respectively. As indicated by arrows in FIG. 2, the light generated by each light emitting diode module 2 is emitted radially. Of the light emitted radially, the light emitted toward the central portion of the light guide plate 6 is directly guided by the light guide plate 6.

  On the other hand, the light emitted from the light emitting diode module 2 toward the end face of the light guide plate 6 is reflected by the reflector 14 attached to the end face of the light guide plate 6 and directed toward the center of the light guide plate 6. A part of the light reflected by the reflector 14 is guided toward the central portion of the light guide plate 6 through a portion between the concave portions 20 of the light guide plate 6.

  As shown in FIG. 1, a part of the light emitted from the light emitting diode module 2 in the direction of the front surface of the light guide plate 6 (upward in FIG. 1) is reflected by the wall surface of the conical groove 22. Are directed radially in the direction substantially parallel to the light guide plate 6 (horizontal direction in FIG. 1). Part of the light reflected by the groove 22 is guided toward the center of the light guide plate 6, and the other part is reflected by the reflector 14 attached to the end face of the light guide plate 6. Further, a part of the light emitted from the light emitting diode module 2 toward the front surface of the light guide plate 6 is reflected by the reflector 14 attached to the front surface side of the light guide plate 6 and returned to the inside of the light guide plate 6 again.

  Monochromatic light of each color emitted from each light emitting diode module 2 is mixed while being guided by the light guide plate 6 to be white light. In particular, in the surface light source device 1 of the present embodiment, since the distance between the concave portions 20 of the light guide plate 6 is long, the distance that the light emitted from each light emitting diode module 2 passes through the inside of the light guide plate 6 is long. Each monochromatic light is effectively mixed. In the present embodiment, the monochromatic light of each color is turned into white light at a mixing distance of about 15 mm to 30 mm from the center of each light emitting diode module 2, so that the effective vertical width that can be used as a surface light source of white light is about 320 mm. It becomes.

While being guided by the light guide plate 6, light is mixed to white light is reflected by the back surface side of the diffuse reflector 12 or dot print 16 of the light guide plate 6, and is emitted from the front surface of the light guide plate 6. White light emitted from the front surface of the light guide plate 6 passes through the diffusion film 8 and the prism sheet 10 and is emitted from the surface light source device 1.

  According to the surface light source device of the first embodiment of the present invention, since the interval between the concave portions for inserting the light emitting diodes is wide with respect to the mounting pitch of the light emitting diodes, the monochromatic light emitted from each light emitting diode is effective. Can be mixed. For this reason, it is possible to ensure a long effective width with respect to the size of the light guide plate.

  In addition, according to the surface light source device of the first embodiment of the present invention, since the conical groove is formed so as to face each light emitting diode module, the light emitted from the light emitting diode module is transmitted to the light guide plate. It can be reflected in a parallel direction. For this reason, even if a light emitting diode module is used, emitted light can be efficiently incident on the light guide plate.

Next, a modification of the surface light source device according to the first embodiment of the present invention will be described with reference to FIG. In this modification, the shape of the bottom surface of the light emitting diode insertion recess into which each light emitting diode module 2 is inserted differs from the shape of the groove formed corresponding to the recess.
As shown in FIG. 4, in this modification, the bottom surface 20a of the recess 20 into which the light emitting diode module 2 is inserted is formed in a hemispherical shape. Moreover, the groove | channel 22a formed corresponding to each recessed part 20 is formed in the morning glory shape where the bus-line of the cone-shaped wall surface was curved. By forming the recess and the groove in the shape as shown in FIG. 4, it is possible to improve the incident efficiency of the light emitted from the light emitting diode module to the light guide plate.

  Next, a surface light source device according to a second embodiment of the present invention will be described with reference to FIG. The surface light source device according to the present embodiment is different from the first embodiment in the shape of the light guide plate and the shape of the groove formed on the front side thereof. Accordingly, here, only the points of the second embodiment of the present invention different from the first embodiment will be described, and the same points will be denoted by the same reference numerals and the description thereof will be omitted. FIG. 5 is an enlarged side sectional view showing the vicinity of the end of the surface light source device according to the second embodiment of the present invention. The surface light source device according to the present embodiment is a one-end edge light type surface light source device using a wedge-shaped light guide plate, which is often used in a notebook computer or the like.

  As shown in FIG. 5, the surface light source device 50 according to the second embodiment of the present invention includes a plurality of light emitting diode modules 2, a substrate 4, a light guide plate 52 that guides light emitted from the light emitting diode modules 2, Have Furthermore, the surface light source device 50 of the present embodiment includes a diffusion film 8, a prism sheet 10, a diffuse reflector 12, and a reflector 14. In addition, heat radiating fins 18 are attached to the back side of the substrate 4 via heat radiating sheets (not shown).

  The light guide plate 52 is a transparent resin rectangular plate having a length of about 250 mm and a width of about 370 mm. Further, the light guide plate 52 has a thickness of about 6 mm at a portion of one side where the light emitting diode module 2 is disposed, and is linearly increased from the one side to the other side. Is decreasing. That is, the back surface of the light guide plate 52 is formed with an inclined plane, and is formed so that the thickness decreases from the side where the light emitting diode module 2 is disposed toward the other side. A plurality of recesses 20 for receiving the respective light emitting diode modules 2 are formed at the edge on one back side of the light guide plate 52. The plurality of recesses 20 are arranged in a straight line and in parallel with one horizontal side of the light guide plate 52 and at equal intervals over the entire side. Each light emitting diode module 2 is arranged at a position of about 15 mm from the end of the light guide plate 52.

A groove 54 having a V-shaped isosceles triangle cross section is formed at a position corresponding to each recess 20 on the front side of the light guide plate 52. The groove 54 is a recess having a cross section that linearly extends from one point at the bottom toward the surface of the light guide plate 6, and extends along one side of the light guide plate 52 (in a direction perpendicular to the paper surface of FIG. 5). ing. The vertical angle of the V-shaped cross section of each groove 54 is about 90 °, the width of the groove 54 on the surface of the light guide plate 52 is about 5 mm, and the depth is about 2.5 mm. Moreover, the groove | channel 54 is extended so that the center of each cylindrical recessed part 20 and the position of the vertex of the groove | channel 54 may correspond.
Further, a white diffuse reflector is employed as the reflector 14.

  A part of the light emitted from the light emitting diode module 2 toward the front surface of the light guide plate 52 (upward in FIG. 5) is reflected by the wall surface of the groove 54 and directed toward both sides of the groove 54. Part of the light reflected by the groove 54 is guided toward the center of the light guide plate 52, and the other part is reflected by the reflector 14 attached to the end face of the light guide plate 52.

  In the present embodiment, the monochromatic light of each color is turned into white light at a mixing distance of about 15 mm to 30 mm from the center of each light emitting diode module 2, so that the effective width (vertical) that can be used as a surface light source of white light is About 220 mm.

According to the surface light source device of the second embodiment of the present invention, since the groove formed in the light guide plate is a linear groove having a triangular cross section, the groove can be easily formed.
Next, a surface light source device according to a third embodiment of the present invention will be described with reference to FIG. The surface light source device according to the present embodiment is different from the first embodiment in that the light emitting diode module is disposed in addition to the edge of the light guide plate. Accordingly, here, only the points of the third embodiment of the present invention different from the first embodiment will be described, and the same points will be denoted by the same reference numerals and the description thereof will be omitted. FIG. 6 is an enlarged side sectional view showing the vicinity of the end of the surface light source device according to the third embodiment of the present invention.

  As shown in FIG. 6, the surface light source device 60 according to the third embodiment of the present invention includes a plurality of light emitting diode modules 2, a substrate 4, a light guide plate 62 that guides light emitted from the light emitting diode modules 2, Have Further, the surface light source device 60 of the present embodiment includes the diffusion film 8, the prism sheet 10, the diffusion reflector 12, the side reflector 64, and the top reflector 66. In addition, heat radiating fins 18 are attached to the back side of the substrate 4 via heat radiating sheets (not shown). In the surface light source device 60 according to the present embodiment, the elongate substrate 4 on which the plurality of light emitting diode modules 2 are mounted is disposed not only on the edge portions on both sides of the light guide plate 62 but also in the center portion. 4 rows are arranged.

The light guide plate 62 is a transparent resin rectangular plate having a length of about 410 mm and a width of about 730 mm. Four rows of recesses 20 for receiving the respective light emitting diode modules 2 are formed on one back side of the light guide plate 62. The row of the recesses 20 is formed over the entire side in parallel with the horizontal side of the light guide plate 62 .

A conical groove 22 is formed at a position corresponding to each recess 20 on the front side of the light guide plate 62. Since the shape of the groove 22 and the position with respect to each recess 20 are the same as in the first embodiment, the description thereof is omitted.
Further, a side reflector 64 is attached to the end face of the light guide plate 62, and is configured to reflect light that has reached the end face of the light guide plate 62. Further, a plurality of elongated top reflectors 66 are respectively attached to the front surface side of the light guide plate 62 so as to cover each row of the light emitting diode modules 2, and the direction from the light emitting diode module 2 to the front surface of the light guide plate 62 ( The light emitted upward (in FIG. 6) is not directly emitted from the light guide plate 62. In addition, a diffusion sheet 68 is provided on the light guide plate instead of a diffusion film for uniformization.

  A part of the light emitted from the light emitting diode module 2 toward the front surface of the light guide plate 62 (upward in FIG. 6) is reflected by the wall surface of the groove 22 and reflected from the groove 22 in the radial direction. Most of the light emitted around the groove 22 is reflected by the top reflector 66. The top reflector 66 on the light guide plate 62 is printed with a density pattern so that the light emitted from the surface light source device 60 does not have uneven brightness or uneven color. The density is such that most is reflected. Further, the light is diffused by the diffusion sheet 68 and the diffusion film 8 to be uniform. This light guide plate increases the amount of diffusing agent, and achieves a uniform light source without applying white printing on the back side, but reduces the amount of diffusing agent to make it uniform on the back surface of the light guide plate. Even better with white dot printing.

  According to the surface light source device of the third embodiment of the present invention, a large area surface light source device used for a large-sized liquid crystal television or the like can be configured.

  Next, a surface light source device according to a fourth embodiment of the present invention will be described with reference to FIG. The surface light source device according to the present embodiment is different from the first embodiment in the structure of the light emitting diode module substrate and the manner of coupling with the light guide plate. Accordingly, only the points of the fourth embodiment of the present invention that are different from the first embodiment will be described here, and the same points will be denoted by the same reference numerals and the description thereof will be omitted. FIG. 7 is an enlarged side sectional view showing the vicinity of the end of the surface light source device according to the fourth embodiment of the present invention.

  As shown in FIG. 7, the surface light source device 70 according to the fourth embodiment of the present invention includes a plurality of light emitting diode array modules 72 and a light guide plate 76 that guides light emitted from the light emitting diode array modules 72. . Furthermore, the surface light source device 70 of the present embodiment includes the diffusion film 8, the prism sheet 10, the diffusion reflection plate 12, and the reflector 14. In addition, heat radiating fins 18 are attached to the back side of the substrate 4 via heat radiating sheets (not shown).

The light guide plate 76 is a transparent resin rectangular plate having a thickness of 6 mm, a length of about 370 mm, and a width of about 420 mm. The light emitting diode array module 72 emits light that can be regarded as monochromatic light of 1 mm ² of red (R), green (G), and blue (B) on a 210 mm aluminum substrate. Various types of light emitting diode chips 71 are aligned at intervals of approximately 10 mm. Each light emitting diode chip is for driving a large current, and in this embodiment, a current of about 300 mA is passed through the light emitting diode chip 71. Furthermore, the number of light emitting diode chips 71 of each color is configured to be R (71a): G (71b): B (71c) = 1: 2: 1.

In the present embodiment, two light emitting diode array modules are arranged in close contact with the light guide plate on the back side from the lateral end face of the light guide plate. Further, the substantially conical grooves on the front surface side of the light guide plate have a diameter of 5 mm and a depth of 2.5 mm at the same 10 mm intervals as the light emitting diode chip.

  In the present embodiment, the monochromatic light of each color is converted into white light at a mixing distance of about 10 mm to 20 mm from the center of each light emitting diode array module 72, so that the effective width (vertical) that can be used as a surface light source of white light. Is about 320 mm.

  Next, a surface light source device according to a fifth embodiment of the present invention will be described with reference to FIG. The surface light source device according to the present embodiment differs from the fourth embodiment in the structure and shape of the light emitting diode module substrate and the manner of coupling with the light guide plate. Accordingly, only the points of the fifth embodiment of the present invention different from the fourth embodiment will be described here, and the same points will be denoted by the same reference numerals and the description thereof will be omitted. FIG. 8 is an enlarged side sectional view showing the vicinity of the end of the surface light source device according to the fifth embodiment of the present invention.

  As shown in FIG. 8, the surface light source device 80 according to the fifth embodiment of the present invention includes a plurality of light emitting diode array modules 82 and a light guide plate 86 that guides light emitted from the light emitting diode array modules 82. . Furthermore, the surface light source device 80 of the present embodiment includes the diffusion film 8, the prism sheet 10, the diffusion reflection plate 12, and the reflector 14. In addition, heat radiating fins 18 are attached to the back side of the substrate 4 via heat radiating sheets (not shown).

Next, a detailed configuration of the light emitting diode array module 82 will be described with reference to FIGS. As shown in FIG. 3, the light-emitting diode array module 82 is obtained by mounting a light-emitting diode chip 71, which is a PN junction semiconductor, on an aluminum substrate with good heat dissipation. 9 to 10 are views in which a concave shape is given to the light emitting diode array module substrate, and a light emitting diode chip is arranged on the bottom surface. In FIG. 9, nine 0.3 mm ² chips are mounted in parallel on a 2 mm ² silicon submount substrate, and the submount substrate is mounted on a concave surface processed at an interval of 15 mm on an aluminum substrate. . The concave surface of the aluminum substrate has a bottom surface of about 3 mm, an outer shape of about 5 mm, and a depth of 0.5 mm. That is, the concave side wall serves as a reflector. In this example, after a pattern was formed on an aluminum substrate, a concave-surface processing was performed on the pattern, and a reflector-integrated substrate having a reflector function was used. The number of submount substrates of each color is configured to be R (71a): G (71b): B (71c) = 1: 2: 1. Each light emitting diode chip is designed to flow a drive current of 50 mA.

In FIG. 10, a 1 mm ² chip is directly mounted on a concave surface processed at an interval of 15 mm on an aluminum substrate. The concave surface of the aluminum substrate has a bottom surface of about 2 mm, an outer shape of about 4 mm, and a depth of 0.5 mm. The number of light emitting diode chips 71 of each color is configured to be R (71a): G (71b): B (71c) = 1: 2: 1. Each light emitting diode chip is designed to flow a drive current of 300 mA.
The light guide plate 86 is a transparent resin rectangular plate having a thickness of 6 mm, a length of about 370 mm, and a width of about 420 mm.

In this embodiment, two light emitting diode array modules are arranged on the back side from the lateral end face of the light guide plate. The positions of the chips and submounts of the light emitting diode array module are designed to match the positions of the light deflection recesses 84 of the light guide plate. The substantially conical groove on the front side of the light guide plate is arranged with the same diameter of 5 mm and the depth of 2.5 mm as the light emitting diode chip.

  In the present embodiment, the monochromatic light of each color is converted into white light at a mixing distance of about 10 mm to 20 mm from the center of each light emitting diode array module 72, so that the effective width (vertical) that can be used as a surface light source of white light. Is about 320 mm.

  Next, a surface light source device according to a sixth embodiment of the present invention will be described with reference to FIG. The surface light source device according to the present embodiment is different from the fifth embodiment in the structure and shape of the light emitting diode module substrate and the manner of coupling with the light guide plate. Therefore, here, only the points of the sixth embodiment of the present invention different from the fifth embodiment will be described, and the same points will be denoted by the same reference numerals and description thereof will be omitted. FIG. 11 is an enlarged side sectional view showing the vicinity of the end of the surface light source device according to the fifth embodiment of the present invention.

  As shown in FIG. 11, the surface light source device 90 according to the sixth embodiment of the present invention guides light emitted from the light emitting diode array module 82 and a plurality of light emitting diode array modules 82 arranged on both surfaces of the light guide plate 96. A light guide plate 96 that emits light. Furthermore, the surface light source device 90 of the present embodiment uses the diffusion film 8, the prism sheet 10, the diffuse reflector 12, the reflector 97, and the light emitting diode array module substrate disposed on both surfaces of the light guide plate 96 to radiate fins. And a heat dissipation holding plate 91 for attaching to the heat sink. Moreover, the heat dissipation fin 18 is attached to the heat dissipation holding plate 91 via a heat dissipation sheet (not shown).

The light guide plate 96 is a transparent resin rectangular plate having a thickness of 6 mm, a length of about 360 mm, and a width of about 420 mm. Further, in the present embodiment, the light emitting diode array module 82 has 0.75 mm ² chips mounted directly on a concave surface processed at 15 mm intervals on an aluminum substrate. The concave surface of the aluminum substrate has a bottom surface of about 2 mm, an outer shape of about 4 mm, and a depth of 0.5 mm. The number of light emitting diode chips 71 of each color is configured to be R (71a): G (71b): B (71c) = 1: 2: 1. Each light emitting diode chip is designed to flow a drive current of 150 mA. It arrange | positions so that a light deflection recessed part may oppose on both surfaces of a light-guide plate. The colors of the light emitting diode chips facing each other are shifted so as to facilitate mixing.

  In the present embodiment, the monochromatic light of each color is turned into white light at a mixing distance of about 10 mm to 20 mm from the center of each light emitting diode array module 82, so that it has an effective width (vertical) that can be used as a surface light source of white light. Is about 320 mm.

  As mentioned above, although preferable embodiment of this invention was described, a various change can be added to the embodiment mentioned above within the range of the technical idea described in the claim. In the third embodiment described above, the light emitting diode modules for each color are arranged in one row. However, in order to increase the amount of light, the light emitting diode modules for each color can be alternately arranged in two rows. . In this case, it is preferable to arrange green light emitting diode module rows that are easily mixed on the inside and red and blue light emitting diode module rows on the outside. Further, in the fifth embodiment, the frame can be further reduced by arranging light-emitting diode chip assemblies (white light emission as a whole) of each color at regular intervals.

It is side surface sectional drawing of the surface light source device by 1st Embodiment of this invention. It is a plane side sectional view of the surface light source device by a 1st embodiment of the present invention. It is an expanded sectional view of the part to which the light emitting diode module is attached of the surface light source device by 1st Embodiment of this invention. It is an expanded sectional view of the part in which the light emitting diode module is attached in the modification of the surface light source device of 1st Embodiment of this invention. It is side surface sectional drawing of the surface light source device by 2nd Embodiment of this invention. It is side surface sectional drawing of the surface light source device by 3rd Embodiment of this invention. It is side surface sectional drawing of the surface light source device by 4th Embodiment of this invention. It is side surface sectional drawing of the surface light source device by 5th Embodiment of this invention. It is a top view of the light emitting diode array module of the surface light source device by 5th Embodiment of this invention. It is a top view of the light emitting diode array module of the surface light source device by 5th Embodiment of this invention. It is side surface sectional drawing of the surface light source device by 6th Embodiment of this invention. It is side surface sectional drawing which shows an example of a surface light source device. It is a plane side sectional view showing an example of a surface light source device. It is side surface sectional drawing which shows another example of a surface light source device. It is a plane side sectional view showing other examples of a surface light source device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface light source device by 1st Embodiment of this invention 2 Light emitting diode module 4 Board | substrate 6 Light guide plate 8 Diffusion film 10 Prism sheet 12 Diffuse reflection board 14 Reflector 16 Dot printing 18 Radiation fin 20 Concave part 22 Groove 24 Light emitting diode chip 26 Heat sink 28 Lead frame 30 Lead wire 32 Resin 50 Surface light source device according to the second embodiment of the present invention 52 Light guide plate 54 Groove 60 Surface light source device according to the third embodiment of the present invention 62 Light guide plate 64 Side reflector 66 Top reflector 68 Diffusion film 70 Surface light source device according to the fourth embodiment of the invention 71 Light emitting diode chip 72 Light emitting diode array module 73 Light emitting diode array module sealing resin 77 Groove 80 Surface light source device according to the fifth embodiment of the present invention 82 Light emitting diode Ray module 83 light emitting diode array module sealing resin 84 optical deflector recess 86 a third embodiment according to the surface light source device 91 radiating holding plate 96 light guide plate 97 reflector of the light guide plate 90 present invention

Claims (5)

One or more light emitting diode arrays in which a plurality of light emitting diode chips having two or more different wavelengths are arranged on one substrate, each light emitting diode chip is sealed with resin, and is arranged in close contact with the back side of the light guide plate Module,
Light deflection recesses are formed at positions corresponding to the respective light-emitting diode chips of the light-emitting diode array module in alignment with the back side, and a plurality of substantially conical shapes are formed at positions corresponding to the light deflection recesses on the front side. A light guide plate with grooves,
A surface light source device comprising: an end face of the light guide plate; and a reflector mounted on the row of the substantially conical grooves. One or more light emitting diode arrays in which two or more types of light emitting diode chips having different wavelengths are arranged on a single substrate, each light emitting diode chip is sealed with resin, and is closely attached to the back side of the light guide plate Module,
Light deflection recesses are formed at positions corresponding to the respective light emitting diode chips of the light emitting diode array module in alignment with the back side, and the rows of the light deflection recesses are positioned at positions corresponding to the rows of the light deflection recesses on the front side. A light guide plate formed with an elongated groove having a substantially V-shaped cross section formed so as to extend in parallel with
Having an end face of the light guide plate and a reflector mounted on the elongated groove having the substantially V-shaped cross section;
A surface light source device. One or more light emitting diode arrays in which two or more types of light emitting diode chips having different wavelengths are arranged on a single substrate, each light emitting diode chip is sealed with resin, and is closely attached to the back side of the light guide plate Module,
A light guide plate in which light deflection recesses are formed in alignment on both the front side and the back side at positions corresponding to the respective light emitting diode chips of the light emitting diode array module;
And a reflector attached to an end face of the light guide plate. A plurality of the light emitting diode array modules are arranged,
The surface light source device according to claim 3 . The light emitting diode array module has a plurality of light emitting diode chip assemblies dispersedly arranged, and has a light guide plate in which the light deflection recesses or the substantially conical grooves are formed at positions corresponding to the respective assemblies. ,
What Re one wherein the surface light source device according to claims 1 to 4.

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