JP2007059216A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device high in heat radiation capability and having high output. <P>SOLUTION: This light emitting device includes: a board 3 with a light emitting diode 4 arranged thereon; a light guide body 5 for guiding light of the light emitting diode 4; a casing 1 having a recessed part for housing the board 3 and the light guide body 5; and an elastic member 8 for applying pressure to the board 3; and characterized in that one-side end 8a of the elastic member 8 presses the board 3 disposed along a side wall of the recessed part toward the side wall from the recessed part side. In addition, the elastic member 8 is a plate material having a shape along the bottom surface of the recessed part, an end 8b thereof formed in a direction different from that of the end 8a pressing the board 3 presses a second side wall formed in a direction different from that of the first side wall along the board 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor light emitting device used for an illumination type switch, a liquid crystal backlight, various illuminations, etc., and particularly to provide a semiconductor light emitting device that emits light with high reliability and high output.

  Nowadays, semiconductor light-emitting devices such as planar light sources using light-emitting diodes (hereinafter sometimes referred to as LEDs) for liquid crystal backlights and the like are utilized by taking advantage of their small size, low power consumption, and vibration. ing. In particular, since LEDs that emit mixed color light including white are developed with one chip and two terminals that can be used for full-color liquid crystals, they are rapidly spreading as light sources for mobile phones and in-vehicle use.

  As an example of such an optical semiconductor device, there is a semiconductor light emitting device disclosed in JP-A-2001-312919. The semiconductor light-emitting device includes a substrate on which the light-emitting diodes are disposed, a light guide that guides light of the incident light-emitting diodes in a predetermined direction, a housing that has a recess that houses the substrate and the light guide, Is provided.

  Such a semiconductor light emitting device has an elastic member for bringing the light emitting surface of the light emitting diode into contact with the end surface of the light guide plate in order to introduce light from the light emitting diode into the light guide plate without leakage. For example, an elastic member is provided between the substrate on which the light emitting diode is disposed and the inner wall surface of the housing that faces the main surface of the substrate. The elastic member presses the light emitting surface of the substrate and the light emitting diode disposed on the substrate toward the end surface of the light guide plate by the elastic force. In addition, the end surface opposite to the end surface of the light guide plate with which the light emitting surface is in contact is in contact with a side wall different from the side wall of the housing on which the substrate is arranged. Such an elastic member can be formed, for example, by projecting a part of a metal flat plate forming the inner wall surface of the concave portion of the housing in the direction of the substrate to form a spring piece.

  By such an elastic member, the light emitting surface of the light emitting diode and the end surface of the light guide plate are brought into contact with each other, so that light from the light emitting diode can be incident on the light guide plate without leakage. Furthermore, by giving the elastic member a predetermined elastic force, it is possible to prevent the substrate or the light guide plate on which the light emitting diodes are arranged from falling off the casing.

JP 2001-312919 A.

  However, since the substrate on which the light emitting diodes are arranged transmits the pressure to the side wall of the housing via the light guide plate, the elastic member as described above cannot sufficiently apply the pressure to the substrate. Therefore, the adhesion between the substrate on which the light emitting diode is disposed and the inner wall surface of the housing on which the substrate is disposed is lowered. Furthermore, if an elastic member is interposed between the substrate and the side wall of the housing, it is not sufficient to radiate heat from the substrate to the housing. For this reason, in the conventional light emitting device, the heat dissipation from the light emitting diode is reduced.

  Further, when a part of the housing is made of an elastic member, the elastic force may be reduced after a long period of use. For example, when the material of the housing is aluminum in order to reduce the weight of the light emitting device, the pressure gradually decreases due to heat released from the light emitting diode to the housing. For this reason, the adhesion between the substrate and the inner wall surface of the housing disposed along the substrate is lowered, and the heat dissipation from the light emitting diode through the substrate is gradually lowered.

  It is also conceivable that the end face of the light guide that is in contact with the light emitting surface is melted due to heat generated by the high output of the light emitting diode. Temporarily, if the light incident end face of the light guide is damaged by heat due to high output and long-term use, it will adversely affect the optical characteristics such as color misregistration and color unevenness, and make it a highly reliable light emitting device I can't.

  Accordingly, an object of the present invention is to provide a highly reliable light-emitting device capable of improving heat dissipation from a light-emitting diode and capable of emitting light with high output.

  In order to achieve the above object, a light emitting device according to the present invention includes a substrate on which a light emitting member is disposed, a light guide that guides light from the light emitting member, and a recess that houses the substrate and the light guide. And a resilient member that presses the substrate disposed along the side wall of the recess against the side wall.

  The elastic member is a plate member having a shape along the bottom surface of the concave portion, and a second end provided in a different direction from the first end pressing the substrate is a first end against which the substrate is pressed. It is preferable to press the second side wall provided in a different direction from the one side wall.

  It is preferable that a substrate on which a light emitting member is disposed is further provided between the second end portion and the second side wall, and the substrate is pressed against the second side wall by the elastic member.

  It is preferable that a substrate on which a light emitting member is disposed is provided between the other end and the second side wall, and the substrate is pressed against the second side wall by the elastic member.

  Preferably, the elastic member is a plate whose cross section is bent in a U shape, and the side wall of the housing along the substrate and the substrate is sandwiched by the elastic member.

  It is preferable that there is a space between the light emitting surface of the light emitting member and the end surface of the light guide facing the light emitting surface.

  It is preferable that the end portion of the elastic member is bent so as to follow the shape of the main surface of the substrate to be contacted or the inner wall surface of the recess.

  The present invention can improve the adhesiveness between the substrate on which the light emitting member is disposed and the housing, and thus the heat dissipation of the light emitting member is improved, and a highly reliable light emitting device capable of high output light emission is provided. Can do.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below illustrates the light emitting device for embodying the technical idea of the present invention, and the present invention does not limit the light emitting device to the following.

  Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention only to a specific description unless otherwise specified. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  1 to 3 are cross-sectional views of the light emitting device of this embodiment. A light emitting device comprising: a substrate on which a light emitting member is disposed; a light guide that guides light of the light emitting member; a housing having a recess that houses the substrate and the light guide; and an elastic member that applies pressure to the substrate. In the device, the present inventor has made various studies in order to obtain a sufficient pressure on the housing of the substrate and to improve the heat dissipation. As a result, the above-mentioned problem is solved by pressing one end of the elastic member along the side wall of the recess toward the side wall from the side of the recess. It came to do. That is, the elastic member according to the present invention is not formed by applying an elastic force to a part of the casing, but is an independent member, and a light guide or the like is provided between the substrate and the side wall of the casing. There is no need to transmit the pressure through the cable. Therefore, the substrate can be more firmly fixed to the side wall of the housing than in the past by directly pressing the substrate from the recess side toward the side wall of the housing.

  As shown in FIG. 1 or FIG. 2, the elastic member of the present embodiment is a plate material having a shape along the bottom surface of the recess of the housing. The elastic member includes a first end that abuts or presses the main surface of the substrate on which the light emitting member is disposed, or another member, and a second end formed in a different orientation. And have. The second end portion presses the second side wall facing the first side wall on which the substrate is disposed in contact with or through another member. Accordingly, the elastic member can easily press the substrate against the side wall of the casing by using the side wall of the concave portion of the casing without using the light guide.

  The elastic member can apply pressure to the side wall of the housing via another member such as a heat radiating member or a cushioning material. The buffer material is, for example, an insulating material such as resin or elastic rubber, and an elastic member made of a conductive material can be insulated from the conductor wiring of the substrate. In addition, stray light emitted from the light emitting diode or light leaking from the light guide can be suppressed. At this time, it is preferable that the buffer material has a light reflecting function by containing a light diffusing material such as silica or alumina, or by using a material having high reflectance.

  By the way, the elastic member of the light emitting device according to the present invention applies a pressure from the recess side toward the side wall forming the recess. Thereby, compared with the conventional light-emitting device which fixes the opening part of the recessed part of a housing | casing using a leaf | plate spring and pinches | interposes a board | substrate from the opening part side, the thickness of a light-emitting device can be reduced in thickness about the elastic member. .

  Note that the elastic member of the present embodiment is not limited to one in which the second end presses the side wall of the housing. That is, the second end portion can be fixed to the bottom surface of the housing. For example, the hook-shaped second end can be hooked into a hole formed on the bottom surface, or can be fixed by a method such as an adhesive or welding. Further, the elastic member of the present embodiment is not limited to the one that presses the main surface of the substrate, and is arranged so as to apply pressure to the substrate by pressing a light emitting member package or the like disposed on the substrate. Also good.

  As shown in FIG. 2, a light emitting device according to another aspect is provided with a first light emitting device disposed on the other side wall facing the first side wall, facing the first substrate disposed along one side wall of the housing. Two substrates are provided. These substrates are pressed against the side wall of the housing 1 by the end 8a and the end 8b of the elastic member 8 from the side where the light emitting member is disposed. Thereby, the elastic member can easily apply pressure to the plurality of substrates with one elastic member using the main surfaces of the plurality of substrates arranged to face each other. That is, in the light emitting device according to the present invention, since the substrate is fixed only by sandwiching the substrate between the end portion of the elastic member and the side wall of the housing, the design of the light emitting device is greatly changed when the substrate is further added. The substrate can be mounted on the housing without need.

  A light emitting device according to another aspect of the present invention is a plate member in which a cross section of the elastic member is bent in a U shape, and the side wall of the concave portion along the substrate is sandwiched by the elastic member. It is preferable. Thereby, the space | interval of the edge part of an elastic member can be made smaller than the elastic member arrange | positioned along the bottom face of a housing | casing, and a bigger press can be obtained. Therefore, the board | substrate with which the light emitting member is arrange | positioned is firmly fixed by the side wall of a housing | casing, and can improve the heat dissipation of a light-emitting device.

  As shown in FIG. 1 or FIG. 3, it is preferable that there is a space between the light emitting surface of the light emitting member and the end surface of the light guide facing the light emitting surface. Thereby, the end surface of the light guide is not melted by the heat radiation of the light emitting member, and a highly reliable light emitting device can be obtained.

  As shown in FIG. 1 or FIG. 3, it is preferable that the end of the elastic member is bent so as to follow the shape of the main surface of the substrate to be contacted or the side wall of the recess. Thereby, sufficient elastic force can be obtained and a press can be more effectively applied to each member. Hereinafter, each structure of this form is explained in full detail.

(Light emitting member)
The light emitting member in this embodiment refers to a member that emits light that can be incident on a light guide, such as a semiconductor light emitting element such as a light emitting diode or a semiconductor laser, a cold cathode ray tube, or a light source selected and combined variously. In this specification, although a light emitting diode is demonstrated, it is not limited to this. The light emitting diode can be variously selected depending on the dominant wavelength of light emitted from the semiconductor layer. In particular, a light-emitting diode that emits white mixed light is preferably used. Such light emitting diodes include a combination of light emitting diodes that emit RGB colors, a light emitting diode including a semiconductor light emitting element, and a phosphor that emits light excited by light emitted from the semiconductor light emitting element. There are various types. A semiconductor light emitting device capable of emitting blue light can emit light with high brightness by using, for example, a gallium nitride compound semiconductor.

  In addition, the light emitting diode in this embodiment includes a package having a recess. The electrode exposed in the recess and the LED chip disposed in the recess are electrically connected by a conductive wire such as a gold wire or a conductive paste such as an Ag-containing epoxy resin. A surface mount type light emitting diode sealed with a light transmitting resin such as an epoxy resin is formed in the package.

  The package used in this embodiment is preferably one in which an LED chip can be disposed at the bottom of the recess, and various resins such as epoxy resin, silicone resin, acrylic resin, PBT (polybutylene terephthalate), liquid crystal polymer, and aromatic nylon are used. And is preferably formed. In particular, in order to efficiently extract light from the LED chip, it is preferable that the package appropriately mix calcium carbonate, aluminum oxide, or titanium oxide in the various resins. This is because a package with high reflectance can be configured.

  The package may be a ceramic package obtained by laminating and firing ceramic green sheets. Since the ceramic package is superior in heat resistance and light resistance as compared to a package made of a resin material, a high-output and highly reliable semiconductor light-emitting device can be obtained. In the ceramic package having a recess, the inner wall surface of the recess is preferably a reflection surface made of a metal material having a high light reflectance. Thereby, since the light from the light emitting element is not absorbed by the ceramic, a light emitting diode having excellent light extraction efficiency can be obtained.

  The package is preferably filled with an LED chip and a translucent resin electrically connected to the lead electrode. Here, the translucent resin that covers the LED chip may contain a fluorescent material as necessary.

The fluorescent material used in the present embodiment converts the wavelength of the LED chip light. That is, the fluorescent material absorbs at least a part of the light of the LED chip and emits light having a different wavelength. Here, the phosphor is preferably a phosphor that converts light from the LED chip to a longer wavelength side. When light from the LED chip is high-energy short-wavelength visible light, organic phosphors such as perylene derivatives, ZnCdS: Cu, and YAG: Ce (a kind of aluminum oxide phosphor) (for example, YAlO ₃ : Ce). , Y ₃ Al ₅ O ₁₂ : Ce), and inorganic phosphors such as nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ activated by Eu and / or Cr. In particular, the YAG: Ce phosphor absorbs part of the blue light from the LED chip depending on its content and emits yellow light that is a complementary color. Can be formed relatively easily.

(substrate)
The substrate is for mounting and fixing and arranging the light emitting member, and is provided with conductor wiring for supplying power to the light emitting member. For example, it can be suitably formed by a glass epoxy substrate on which a conductive pattern made of copper foil or the like is formed, or a metal body bonded with an insulating resin. Or it can be set as the board | substrate with high heat dissipation by which conductor wiring was given to the metal material which consists of aluminum and copper via the insulating material. In this embodiment, in order to apply the elastic force from the elastic member uniformly to the substrate, a material having a relatively high strength is preferable, and a plate material made of a metal material is preferable. Moreover, it is preferable that a mounting board | substrate is closely_contact | adhered and arrange | positioned through a heat conductive member like a heat dissipation sheet.

(Light guide)
The light guide in this embodiment can guide the light from the light emitting member incident from a part of the end surface by utilizing the internal reflection, and can emit light in a desired shape from a predetermined light emitting surface. Is. Therefore, depending on the desired shape of the light emitting surface, various shapes such as a pointer for a meter needle and a plate shape usable as a liquid crystal backlight light source can be taken. The light guide has translucency in order to efficiently emit light from the light emitting diode or light obtained by wavelength conversion of the light from the light emitting surface. As a material for such a light guide, various materials such as acrylic resin, epoxy resin, and glass are preferably exemplified.

(Casing)
The housing in this embodiment is a member that houses and holds at least a substrate on which a light emitting member is disposed and a light guide. As the case, various types such as resins and metals containing various light diffusing agents are preferably mentioned. In particular, in consideration of heat dissipation and light reflection of a light emitting diode that generates heat, metals such as nickel, iron, copper, and aluminum, and various alloys such as stainless steel are more preferably used. The size and shape of the housing can be variously selected according to the size and shape of the light guide, the light emitting diode, and the substrate.

(Elastic member)
The elastic member in this embodiment is a member that presses the substrate on which the light emitting member is disposed in the direction of the side wall from the concave portion side of the housing. Therefore, an elastic member such as a rubber, a spring (including a leaf spring or a spring-like member) or a resin having various elasticity can be provided separately to form an elastic member. Note that the end of the leaf spring-like elastic member is bent by a predetermined size in a direction corresponding to the outside of the concave portion of the casing, so that a predetermined elastic force is applied before being placed in the casing. Can be kept. Thereby, a heat radiating member and a shock absorbing material can be easily interposed between the side wall of the housing and the end of the elastic member.

  The elastic member itself is formed of a highly reflective material, or the surface of the elastic member is covered with a highly reflective material. As such a highly reflective material, for example, silver, aluminum, rhodium or the like is selected. Thereby, the light extraction efficiency of the light emitting device can be improved. The elastic member may be disposed on the light emission observation surface side of the light guide by providing an opening to the extent that light emission is observed. However, in order to improve the light extraction efficiency from the light emitting device, the light guide It is preferable to arrange it on the back side (main surface opposite to the emission observation surface). In particular, when the elastic member is disposed on the back side of the light guide, it is preferable to use such an elastic member as the reflecting member. Thereby, a member such as a reflection sheet that reflects light incident on the light guide toward the emission observation surface can be replaced with an elastic member. Therefore, the number of parts of the light-emitting device can be reduced, and a light-emitting device with high mass productivity can be obtained.

  Moreover, the shape which hold | maintains a light guide can be provided in the edge part of an elastic member. For example, the light guide is held by its elastic force as a spring piece in which a part of an elastic member made of a metal flat plate is cut out. Thereby, the light guide can be stably fixed without dropping from the housing.

  Examples according to the present invention will be described in detail below. Needless to say, the present invention is not limited to the following examples.

  FIG. 1 is a cross-sectional view of the light emitting device according to this example. In the light emitting device according to this example, a substrate 3 on which a light emitting diode is mounted is disposed along the side wall of the recess 6 of the housing 1, and the main surface of the substrate 3 on the light emitting diode side is an elastic member 8. Is pressed by the end 8a. The elastic member 8 is a metal flat plate that is bent along the bottom shape of the recess 6 on the back side of the light guide 5. One end 8a of the elastic member 8 is bent along the main surface of the substrate 3 on which the light emitting diodes are arranged. The other end 8b of the elastic member 8 is bent and brought into contact with the side wall on the other side of the side wall on which the substrate 3 is disposed.

  The light guide plate 5 is disposed in the concave portion of the housing 1 above the elastic member 8 so that the end surface thereof faces the light emitting surface of the light emitting diode. The elastic member 8 is disposed along a gap formed between the light guide 5 and the bottom surface of the housing 1.

  The back surface opposite to the main surface of the substrate on which the light emitting diodes are arranged faces the side wall of the housing 1 through the heat radiating member 2. Thus, the heat dissipation of the light emitting device can be improved by using the heat dissipation member. In addition, a buffer material 7 is interposed between the end 8 a of the elastic member 8 and the main surface of the substrate 3. The buffer material 7 is an insulating material, and can insulate the elastic member 8 made of a conductive material from the conductor wiring of the substrate 3.

  In the light emitting device of this embodiment, the elastic member 8 applies pressure to the substrate from the concave portion side of the housing 3 in which the elastic member 8 is disposed toward the side wall. Thereby, since the board | substrate 3 closely_contact | adheres to the side wall of the housing | casing 3 through the heat radiating member 2, the heat dissipation from the board | substrate 3 to the housing | casing 1 can be improved.

  FIG. 2 is a cross-sectional view of the light emitting device according to this example. The light emitting device of this embodiment includes another substrate 3 ′ on which a light emitting diode 4 ′ is disposed so as to face the substrate 3 of the first embodiment. The light emitting surface of the light emitting diode 4 ′ disposed on the substrate 3 ′ is opposed to an end surface different from the end surface where the light emitting surface of the light emitting diode 4 faces. In this way, by making light incident on the single light guide 5 from the end faces in a plurality of directions, it is possible to obtain a light emitting device with higher output and uniform light emission.

  The elastic member 8 according to the present embodiment has end portions 8a and end portions 8b that press the main surfaces of the substrate 3 and the substrate 3 ′, respectively. A pressing toward the side wall of the recess is applied from the arranged side. As described above, the elastic member according to the present invention can flexibly cope with a light emitting device having a plurality of substrates without particularly changing the design.

  FIG. 3 is a cross-sectional view of the light emitting device according to this example. The elastic member 9 of the present embodiment is a plate material having a U-shaped cross section corresponding to the shape of the side surface of the substrate 3 and the upper portion of the side wall of the housing 1. One end portion of the elastic member 9 presses the main surface of the substrate 3 on the side where the light emitting diode is disposed via the cushioning material 7, and the other end portion contacts the side wall from the outer wall side of the housing. And press. That is, the elastic member sandwiches the substrate 3 and the upper portion of the side wall of the housing with a predetermined elastic force.

  The elastic member 9 in the present embodiment can be reduced in size as compared with the elastic member 8 disposed along the bottom of the concave portion of the housing. That is, the elastic member 9 can make the interval between the end portions in contact with the side walls of the substrate or the housing smaller than the elastic member 8. Therefore, the light emitting device according to the present example can maintain a stronger elastic force than that of the above example when used at a high output for a long time. Thereby, the board | substrate 3 can be firmly fixed to the side wall of the housing | casing 1, and it can be set as the light-emitting device with high heat dissipation.

  INDUSTRIAL APPLICABILITY The present invention can be used as a planar light source such as a liquid crystal backlight as a semiconductor light-emitting device that is resistant to vibration and is thinned, miniaturized, and reduced in power consumption.

FIG. 1 is a sectional view of a light emitting device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a light emitting device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a light emitting device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Radiating member 3, 3 '... Board | substrate 4, 4' ... Light-emitting member 5 ... Light guide 6 ... Concave part 7 ... Buffer material 8, 9 ... elastic members 8a, 8b ... ends of elastic members

Claims (6)

A substrate on which a light emitting member is disposed;
A light guide for guiding the light of the light emitting member;
A housing having a recess for housing the substrate and the light guide;
A light emitting device comprising: an elastic member that presses a substrate disposed along the side wall of the recess against the side wall.   The elastic member is a plate member having a shape along the bottom surface of the recess, and the second end provided in a different direction from the first end pressing the substrate is pressed against the substrate. The light-emitting device of Claim 1 which presses the 2nd side wall provided in the direction different from a 1st side wall.   The board | substrate with which the light emitting member is arrange | positioned between said 2nd edge part and said 2nd side wall is further provided, The board | substrate is pressed by said 2nd side wall with the said elastic member. The light-emitting device of description.   2. The light emitting device according to claim 1, wherein the elastic member is a plate member whose cross section is bent in a U shape, and the side wall of the housing along the substrate and the substrate is held by the elastic member. apparatus.   5. The light emitting device according to claim 1, wherein the light emitting device has a space between a light emitting surface of the light emitting member and an end surface of the light guide facing the light emitting surface. 6. The light emitting device according to claim 1, wherein an end portion of the elastic member is bent so as to follow a shape of a main surface of the substrate to be contacted or a side wall of the recess.

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