JP2010258093A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device LED which is used suitably as a spot light source. <P>SOLUTION: The light emitting device includes a base having a recess which opens to the upper end face, an LED element mounted on the bottom face of the recess, a translucent member filling the recess, and a wavelength conversion member which is a planar body containing phosphor and is mounted on the upper end face of the base to cover the opening of the recess, wherein the lower surface of the wavelength conversion member is in close proximity to the upper part of the LED element or in tight contact therewith. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an LED light-emitting device that can be suitably used as a point light source.

  Conventionally, light emission that emits light of a color different from that of LED elements such as white by combining LED elements that emit blue light or ultraviolet light with various phosphors using a gallium nitride compound semiconductor An apparatus has been developed (Patent Document 1). Such a light emitting device using an LED element has advantages such as small size, power saving and long life, and is widely used as a light source for display and a light source for illumination.

  Recently, LED elements have been increased in output, but their energy conversion efficiency is not yet sufficient, most of the input electric energy becomes heat, and the amount of generated heat increases with the flowing current.

  In addition, the characteristics of the phosphor depend on the temperature, and as the temperature rises, the light emission efficiency decreases and the luminance decreases. Furthermore, it is also known that the phosphor is deteriorated by heat. For this reason, it is preferable that the LED element and the phosphor are separated from each other because the phosphor is less susceptible to the heat generated by the LED element.

  On the other hand, in a light emitting device that emits light of a color different from the emission color of the LED element by combining the LED element and various phosphors, the phosphor emits light when excited by the light emitted by the LED element. Since the light emitted from the LED element is applied to a wider area of the member as the distance between the member and the phosphor-containing member increases, fluorescence is emitted from the wide area of the member and emitted as light spreading outward. Accordingly, as the LED element and the phosphor-containing member are separated from each other, it becomes difficult to condense or parallelize light emitted from the light emitting device. Therefore, in the light emitting device used as a point light source, the LED element and the phosphor It is preferable that the distance from the member containing is short.

  However, as described above, if the distance between the LED element and the phosphor is short, there is a problem that the phosphor is easily affected by the heat generated by the LED element.

JP-A-7-99345

  The present invention has been made in view of such problems, and it is a main intended problem to provide an LED light-emitting device that can be suitably used as a point light source.

  That is, the light-emitting device according to the present invention includes a base body having a recess opening in the upper end surface, an LED element mounted on the bottom surface of the recess, a translucent member filled in the recess, and a phosphor. A wavelength conversion member that is placed on the upper end surface of the substrate and covers the opening of the recess, and the lower surface of the wavelength conversion member and the upper portion of the LED element are close to each other Or, it is characterized by being close.

  If it is such, since the lower surface of the wavelength conversion member and the upper part of the LED element are close to or in close contact with each other, the light emitted from the LED element irradiates a narrow area of the wavelength conversion member. Since the contained phosphor is excited, fluorescence is emitted from a narrow area of the wavelength conversion member to the outside. For this reason, the light-emitting device according to the present invention works well as a point light source, and the condensing process and the parallelizing process become easy.

  And by making a wavelength conversion member into the plate-shaped body which covers the opening part of a base part crevice, the surface area is increased, heat dissipation is made easy, and the wavelength conversion member by which a wavelength conversion member and an LED element adjoin or contact closely The temperature rise is suppressed, and the luminous efficiency and luminance of the phosphor contained in the phosphor are reduced, and thermal deterioration is prevented.

  In order to position the wavelength conversion member with high accuracy, it is preferable that a protruding member that prevents the wavelength conversion member from moving in the lateral direction is provided on the upper end surface of the base.

  In order to more efficiently dissipate heat from the wavelength conversion member, it is preferable that a translucent heat dissipation member is further placed on the upper surface of the wavelength conversion member.

  In order to suppress the temporal change of the emission color of the light emitting device according to the present invention, it is preferable that the wavelength conversion member is formed by arranging fluorescent regions that emit light of different colors in parallel.

  When the light emitting device according to the present invention emits white light, the LED element emits near-ultraviolet light in order to suppress uneven color tone, and the phosphor emits red light. The phosphor (hereinafter referred to as red phosphor), the phosphor emitting green light (hereinafter referred to as green phosphor), and the phosphor emitting blue light (hereinafter referred to as blue phosphor) are preferable.

  According to the present invention having such a configuration, it is possible to obtain a light-emitting device that acts as a point light source while suppressing changes in phosphor due to heat. For example, the light-emitting device can be used as a light source for a microscope and can be compact. With this lens, the light can be condensed well on the observation object. For this reason, the microscope can be miniaturized by using the light emitting device according to the present invention as a light source.

1 is a schematic perspective view of a light emitting device according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA in FIG. 1. The typical perspective view of the light-emitting device concerning other embodiments. The typical top view of the wavelength conversion member in other embodiments. The typical top view of the wavelength conversion member in other embodiments. FIG. 6 is a schematic cross-sectional view of a light emitting device according to another embodiment.

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

  As shown in FIGS. 1 and 2, the light-emitting device 1 according to the present embodiment includes a base 2 having a recess 22 that opens to the upper end surface 21, an LED element 3 mounted on the bottom surface 221 of the recess 22, and a recess A translucent member 4 enriched in 22, a wavelength conversion member 5 placed on the upper end surface 21 of the substrate 2 and covering the opening of the recess 22, and a translucency placed on the upper surface of the wavelength conversion member 5. The heat radiating member 6 is provided.

Each part will be described in detail.
The base 2 has a recess 22 that opens to the upper end surface 21. For example, a base 2 is formed by molding an insulating material having high thermal conductivity such as alumina or aluminum nitride.

  The base body 2 mounts an LED element 3 to be described later on the bottom surface 221 of the recess 22, and a wiring conductor (not shown) for electrically connecting the LED element 3 to the bottom surface 221. Is formed. This wiring conductor is led to the outer surface of the light emitting device 1 through a wiring layer (not shown) formed inside the base 2 and connected to the external electric circuit board, whereby the LED element 3 and the external electric circuit board are connected. Are electrically connected.

  A wavelength conversion member 5 to be described later is placed on the upper end surface 21 of the base 2, but a protruding member 23 having an L-shaped cross section is provided at the corner of the upper end surface 21 of the base 2. The wavelength conversion member 5 is positioned so as to prevent the conversion member 5 from moving in the lateral direction. Further, the heat of the wavelength conversion member 5 placed on the upper end surface 21 of the base 2 is released through the base 2.

  The LED element 3 is formed, for example, by laminating a gallium nitride-based compound semiconductor in the order of an n-type layer, a light emitting layer, and a p-type layer on a sapphire substrate. Such an LED element 3 emits blue light or ultraviolet light. .

  The LED element 3 is flip-chip mounted on the bottom surface 221 of the concave portion 22 using solder bumps, gold bumps, or the like with the gallium nitride compound semiconductor facing down (the bottom surface 221 side of the concave portion 22).

  The translucent member 4 is filled in the concave portion 22 and seals the LED element 3. For example, the translucent member 4 is made of a silicone resin having excellent translucency and heat resistance and having a small difference in refractive index from the LED element 3. It is.

  The wavelength conversion member 5 is a flat plate having an equal thickness and containing the phosphor 51 therein. The wavelength conversion member 5 is placed on the upper end surface 21 of the base 2 and covers the opening of the recess 22. 3 is close to or close to the top. Examples of such a wavelength conversion member 5 include those in which the phosphor 51 is dispersed in a silicone resin that is excellent in translucency and heat resistance and has a small refractive index difference from the translucent member 4. It may be formed into a sheet or film.

  It does not specifically limit as the fluorescent substance 51 which the wavelength conversion member 5 contains, For example, a red fluorescent substance, a green fluorescent substance, a blue fluorescent substance, a yellow fluorescent substance etc. are mentioned.

  The translucent heat radiating member 6 is for releasing the heat of the wavelength conversion member 5, has a plate-like body, and is placed on the upper surface of the wavelength conversion member 5. As such a translucent heat radiating member 6, what consists of material with high heat conductivity, such as sapphire and diamond, and was excellent in translucency is mentioned, for example.

  Among the light emitting devices 1 according to the present embodiment, the LED element 3 that emits near ultraviolet light is used, and the phosphor 51 that uses a red phosphor, a green phosphor, and a blue phosphor is used. White light is emitted by mixing red light, green light, and blue light emitted by the red, green, and blue phosphors excited by the emitted near-ultraviolet light. The near-ultraviolet light emitted from the LED element 3 does not substantially affect the white color that is the emission color of the light-emitting device 1. Therefore, for example, when the LED element 3 emits blue light, and the blue light is configured to be mixed with light emitted from the phosphor 51 included in the wavelength conversion member 5, the light emitting device Although the color unevenness due to the difference in the optical path length is likely to occur on the light emitting surface 1, the LED element 3 emits near-ultraviolet light, and the phosphor 51 is composed of a red phosphor, a green phosphor and a blue phosphor Some light emitting devices 1 are less likely to cause such uneven color tone.

  The LED element 3 that emits near-ultraviolet light is used, and the mixed light emitted from the light emitting device 1 using the red phosphor, the green phosphor, and the blue phosphor as the phosphor 51 is on the Planck locus. The natural white color is very close to sunlight.

  In the light-emitting device 1 according to such an embodiment, the light emitted from the LED element is generated by the wavelength conversion member 5 because the lower surface of the wavelength conversion member 5 and the upper part of the LED element 3 are close to or in close contact with each other. Since a narrow area is irradiated and the phosphors 51 included in the area are excited, fluorescence is emitted from the narrow area of the wavelength conversion member 5 to the outside. For this reason, the light-emitting device according to the present invention works well as a point light source, and the condensing process and the parallelizing process become easy.

  Moreover, by making the wavelength conversion member 5 into a plate-like body that covers the opening of the base 2 recess 22, the surface area is increased to facilitate heat dissipation, and the wavelength conversion member 5 and the LED element 3 are close to or in close contact with each other. The temperature rise of the wavelength conversion member 5 due to the above is suppressed, and the luminous efficiency and luminance of the phosphor 51 contained therein are reduced, and thermal deterioration is prevented.

  Furthermore, by placing the translucent heat radiating member 6 on the wavelength conversion member 5, it becomes possible to efficiently release heat from the wavelength conversion member 5, and the phosphor 51 included in the wavelength conversion member 5 can be released. It is possible to more effectively prevent a decrease in luminous efficiency and luminance and thermal deterioration.

  The present invention is not limited to the above embodiment.

  For example, the protruding member 23 may have a rectangular cross section as shown in FIG.

  Further, the wavelength conversion member 5 does not have to have the phosphors 51 emitting light of different colors uniformly dispersed, and is provided with fluorescent regions emitting light of different colors in parallel. Also good. That is, for example, as shown in FIG. 4, a red fluorescent region R containing a red phosphor, a green fluorescent region G containing a green phosphor, and a blue fluorescent region B containing a blue phosphor are arranged in the horizontal direction. If it is provided, the blue light emitted from the blue phosphor and the green light emitted from the green phosphor are not absorbed by the other phosphors 51, so that the energy conversion efficiency can be increased, and the wavelength In the conversion member 5, when the red fluorescent region R, the green fluorescent region G, and the blue fluorescent region B are laminated in the thickness direction in this order from the lower surface, the red phosphor closer to the LED element 3 deteriorates faster, The light emission color of the light emitting device 1 is likely to change. However, when the fluorescent regions are arranged in parallel in the horizontal direction, the light emission color of the light emitting device 1 changes because it is difficult for the phosphor 51 to deteriorate. Hateful.

  Further, the mode in which the red fluorescent region R, the green fluorescent region G, and the blue fluorescent region B are arranged side by side is not limited to that shown in FIG. 4, but as shown in FIG. 5, the red fluorescent region R, the green fluorescent region G, and Blue fluorescent regions B may be provided radially.

  Further, as shown in FIG. 5, particles such as alumina, aluminum nitride, silicon carbide, aluminum, copper, silver, gold, carbon, sapphire, and diamond are dispersed around the periphery of the wavelength conversion member 5. The formed heat dissipation area H may be formed. Thus, if the heat dissipation area H is formed at the periphery of the wavelength conversion member 5, the heat of the wavelength conversion member 5 can be released more efficiently.

  Further, in order to block out the ultraviolet light emitted from the LED element 3 without being absorbed by the phosphor 51, the UV cut is applied on the wavelength conversion member 5 or the translucent heat radiating member 6. A filter or the like may be provided.

  Further, the inner wall surface of the recess 22 may function as a reflector by providing a metal thin film having a high reflectance on the inner wall surface of the recess 22 of the base 2.

  Furthermore, the translucent heat radiating member 6 may function as a convex lens, as shown in FIG.

  Further, the LED element 3 may be connected to a wiring conductor provided on the base 2 using wire bonding.

  In addition, the present invention is not limited to the above-described embodiments, and may be configured by appropriately combining some or all of the various configurations described above without departing from the spirit of the present invention.

  Thus, according to this invention, the LED light-emitting device which acts as a point light source, suppressing the change of the fluorescent substance by a heat | fever can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device 2 ... Base | substrate 3 ... LED element 4 ... Translucent member 5 ... Wavelength conversion member 6 ... Translucent heat dissipation member

Claims (5)

A base body having a recess opening in the upper end surface;
LED elements mounted on the bottom surface of the recess,
A translucent member filled in the recess;
A plate-like body containing a phosphor, and a wavelength conversion member that is placed on the upper end surface of the substrate and covers the opening of the recess, and
The light emitting device, wherein a lower surface of the wavelength conversion member and an upper portion of the LED element are close to or in close contact with each other.   The light emitting device according to claim 1, wherein a projecting member that prevents lateral movement of the wavelength conversion member is provided on an upper end surface of the base.   The light emitting device according to claim 1, further comprising a light transmissive heat radiating member placed on an upper surface of the wavelength conversion member.   4. The light emitting device according to claim 1, wherein the wavelength conversion member is formed by arranging fluorescent regions emitting light of different colors in parallel. The LED element emits near ultraviolet light,
5. The light emitting device according to claim 1, wherein the phosphor is a phosphor that emits red light, a phosphor that emits green light, and a phosphor that emits blue light.