JP2006203262A - Light emitting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting apparatus improved in radiated light intensity, and reducing radiated light intensity unevenness or color unevenness. <P>SOLUTION: The light emitting apparatus includes: a substrate 2, a light emitting element 4 mounted on the substrate 2; and a reflecting member 3 having a first reflecting surface 6 placed on the substrate 2 side and a second reflecting surface 8 placed on the outer side. The light emitting apparatus also includes a translucent member 5 containing fluorescent substance to change a wavelength of light emitted from the light emitting element 4, mounted inside the reflecting member 3, and having a light emitting surface 7 placed below the second reflecting surface 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device that converts the wavelength of light emitted from a light emitting element with a phosphor and emits light to the outside.

  A light-emitting device that emits an arbitrary color by a phosphor that converts light such as near-ultraviolet light and blue light emitted from a light-emitting element 14 such as a conventional light-emitting diode (LED) into light of red, green, blue, yellow, etc. 11 is shown in FIG. In FIG. 2, the light emitting device 11 has a mounting portion 12a for mounting the light emitting element 14 at the center of the upper surface, and the inside and outside of the light emitting device 11 are electrically connected electrically from the mounting portion 12a and its periphery. A base 12 made of an insulator on which a wiring conductor (not shown) made of a lead terminal, metallized wiring, or the like is formed, and a through hole that is bonded and fixed to the upper surface of the base 12 and whose upper opening is larger than the lower opening. In addition, the frame 13 whose inner peripheral surface is a reflection surface that reflects the light emitted from the light emitting element 14, and the light of the light emitting element 14 that is filled in the frame 13 is converted to a long wavelength. It is mainly composed of a translucent member 15 containing a phosphor (not shown) and a light emitting element 14 mounted and fixed on the mounting portion 12a.

  The substrate 12 is made of a ceramic such as an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, a glass ceramic, or a resin such as an epoxy resin. When the substrate 12 is made of ceramics, a wiring conductor (not shown) is formed on the upper surface thereof by firing a metal paste made of tungsten (W), molybdenum (Mo) -manganese (Mn), or the like at a high temperature. When the base 12 is made of resin, lead terminals made of copper (Cu), iron (Fe) -nickel (Ni) alloy, etc. are molded and fixed inside the base 12.

  Further, the frame body 13 has a frame shape in which a through hole having an upper opening larger than a lower opening is formed and a reflection surface for reflecting light is provided on an inner peripheral surface of the through hole. Specifically, it consists of metals such as aluminum (Al) and Fe-Ni-cobalt (Co) alloys, ceramics such as alumina ceramics or resins such as epoxy resins, and molding technologies such as cutting, die molding or extrusion molding. It is formed by.

  Further, the reflecting surface of the frame body 13 is formed by polishing and flattening, or by depositing a metal such as Al on the inner peripheral surface of the frame body 13 by vapor deposition or plating. The frame 13 is joined to the upper surface of the base 12 by a brazing material such as solder, silver (Ag) paste, or a joining material such as a resin adhesive so as to surround the mounting portion 12a on the inner peripheral surface.

  The light emitting element 14 is mounted on the mounting portion 12a with a conductive adhesive (not shown) such as solder or Ag paste.

Then, a wiring conductor (not shown) disposed around the mounting portion 12a is electrically connected to the light emitting element 14 via a bonding wire (not shown), and then an epoxy resin containing a phosphor. A light-transmitting member 15 such as silicone resin or the like is filled in the frame 13 so as to cover the light-emitting element 14 with an injection machine such as a dispenser and thermally cured in an oven, so that the light from the light-emitting element 14 is emitted by the phosphor. The light emitting device 11 can convert the wavelength to the long wavelength side and extract light having a desired wavelength spectrum.
JP-A-10-107325

  However, the conventional light emitting device 11 emits light from the light emitting element 14 in the upward direction and is emitted from the light emitting surface 17 that is the upper surface of the translucent member 15, and is emitted in the lateral direction and the lower direction to form a frame. Since the path length passing through the translucent member 15 is different from the light emitted from the light emitting surface 17 after being reflected by the body 13, there is a problem that unevenness of the emitted light intensity and uneven color are likely to occur on the light emitting surface 17. Was.

To solve this problem, that by increasing the angle theta ₃ with respect to the upper surface of the base body 12 of the inner peripheral surface of the frame body 13, to reduce the path length difference of light emitted from the light emitting element 14 in all directions There is a way. However, as the angle θ ₃ is increased, the number of times the light of the light emitting element 14 is reflected inside the frame 13 increases, so that the reflection loss of light and the propagation loss within the translucent member 15 increase. Had problems.

Also, reducing the angle theta ₃ in order to reduce the number of reflections of light in the frame body 13 inside area of the light emitting surface 17 is a light emitting device directivity of the emitted light is lower than 11 increases, as a result, In order to improve directivity, it is necessary to attach a condensing member such as an optical lens to the upper surface of the light emitting surface 17, and there is a problem that it is difficult to reduce the size of the light emitting device 11.

  Furthermore, the arithmetic mean roughness of the inner peripheral surface of the frame 13 surrounding the light emitting element 14 is increased in order to increase the ratio of the phosphor irradiated by the light emitted from the light emitting element 14 and efficiently convert the wavelength of the light. When the light from the light emitting element 14 is scattered, the wavelength conversion efficiency is improved and the emitted light intensity is increased, but the light is emitted to the outside of the light emitting device 11 at a desired radiation angle by scattering in the frame 13. Has a problem that directivity tends to be lowered.

  Conversely, when the inner peripheral surface of the frame 13 surrounding the light emitting element 14 is smoothed, the light from the light emitting element 14 is regularly reflected on the inner peripheral surface, and light is emitted at a desired radiation angle, the emitted light Although the directivity of the light emitting element 14 is regularly reflected on the inner peripheral surface, the ratio of the light irradiating the phosphor other than the regular reflection direction is reduced, the wavelength conversion efficiency is reduced, and the light output is reduced. It had the problem that it deteriorated easily.

  Accordingly, the present invention has been devised in view of such conventional problems, and an object of the present invention is to provide a light emitting device that has high radiated light intensity, high directivity, and very little radiated light intensity unevenness and color unevenness. There is to do.

  The light-emitting device of the present invention includes a base, a light-emitting element mounted on the base, a first reflecting surface disposed on the base and surrounding the light-emitting element, and an external surface. A reflecting member having a second reflecting surface disposed on the side, and a phosphor that converts the wavelength of light emitted from the light emitting element, are provided inside the reflecting member, and A translucent member having a light emitting surface located below the second reflecting surface.

  In the light emitting device of the present invention, a first inclination angle of the first reflection surface is different from a second inclination angle of the second reflection surface.

  In the light emitting device of the present invention, the light emitting element is a light emitting diode made of a nitride semiconductor.

  In the light emitting device of the present invention, the phosphor is excited by light emitted from the light emitting element, and emits light in blue, red and green. In the light emitting device of the present invention, the translucent member is a thermosetting resin filled inside the reflective member.

  The light emitting device of the present invention includes a reflecting member having a first reflecting surface arranged on the base side and a second reflecting surface arranged on the outside side, and a light emitting surface located below the second reflecting surface. The translucent member which has.

  With such a configuration, the light emitting device of the present invention can improve light emission luminance and reduce color unevenness.

  Further, the light emitting device of the present invention can further improve the light emission characteristics because the first inclination angle of the first reflection surface is different from the second inclination angle of the second reflection surface.

  In the light-emitting device of the present invention, the light-emitting element is a light-emitting diode made of a nitride semiconductor, so that the light emission efficiency can be improved.

  In the light-emitting device of the present invention, the phosphor is excited by light emitted from the light-emitting element and emits light having a desired emission spectrum and color by emitting light in blue, red, and green. be able to.

  Moreover, the light-emitting device of this invention can improve luminous efficiency, when the said translucent member is the thermosetting resin with which the inner side of the said reflection member was filled.

The light emitting device of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of a light emitting device of the present invention. In this figure, 1 is a light emitting device of the present invention, 2 is a substrate, 3 is a frame (reflective member), 4 is a light emitting element, 5 is a translucent member containing a phosphor, and 6 is an upper surface of the substrate 2. theta ₁ angle first inner peripheral surface forming a (tilt angle) (reflection surface), 8 the second inner peripheral surface forming an angle (inclination angle) of the theta ₂ with respect to the upper surface of the substrate 2 (the reflecting surface), Reference numeral 2 a denotes a mounting portion for the light emitting element 4 of the base 2.

  The light emitting device 1 of the present invention is attached to the base 2 having the mounting portion 2a of the light emitting element 4 on the upper surface and a resin adhesive or brazing material so as to surround the mounting portion 2a on the outer peripheral portion of the upper surface of the base 2 The frame 3 formed, the wiring conductor (not shown) formed from the mounting portion 2a to the outer surface of the base 2, and the mounting portion 2a is mounted with an adhesive or the like and is electrically connected to the wiring conductor with a bonding wire or the like. Light-emitting elements 4 connected to each other, and a translucent member 5 provided inside the frame 3 so as to cover the light-emitting elements 4 and containing a phosphor that converts the wavelength of light emitted from the light-emitting elements 4. is doing.

  The substrate 2 is made of an insulator made of ceramic such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a glass ceramic, or a resin such as an epoxy resin or a liquid crystal polymer. The base 2 has a placement portion 2 a for placing the light emitting element 4 on the upper surface thereof, and functions as a support member that supports the light emitting element 4.

The frame 3 of the present invention comprises a lower first inner peripheral surface 6 and an upper second inner peripheral surface 8 having different inclination angles of the inner peripheral surface, and the first and second inner peripheral surfaces. When the angles formed by the surfaces 6 and 8 and the upper surface of the substrate 2 are θ ₁ and θ ₂ , respectively, θ ₂ > θ ₁ is satisfied. Thereby, the light emitted from the light emitting element 4 in the lateral direction or the downward direction is efficiently reflected upward by the first inner peripheral surface 6 and is radiated well without repeating the reflection in the frame 3. And the emitted light intensity can be made extremely high. Further, light traveling obliquely upward can be effectively reflected by the second inner peripheral surface 8 in the direction of the light emitting axis of the light emitting device 1, and the directivity of the emitted light can be greatly enhanced. As a result, the light emitting device 1 having both high radiation light intensity and high directivity and excellent light emission characteristics is obtained.

  The frame 3 is made of metal such as Al or Fe-Ni-Co alloy, ceramics such as alumina ceramics or resin such as epoxy resin, and is formed by a molding technique such as cutting, die molding or extrusion molding.

In addition, the angle θ ₁ is preferably 30 ° to 45 °, and the angle θ ₂ is preferably 50 ° to 70 °. Thereby, high radiated light intensity and high directivity can be improved more.

  The translucent member 5 of the present invention is preferably filled below the upper end of the first inner peripheral surface 6. As a result, the path length of the light emitted from the light emitting element 4 in all directions through the translucent member 5 can be made close to uniform, and the variation in wavelength conversion efficiency can be effectively suppressed and the radiated light intensity unevenness can be reduced. Color unevenness can be greatly reduced.

  The first and second inner peripheral surfaces 6 and 8 of the present invention have reflection surfaces that can reflect the light of the light emitting element 4 with a high reflectance. Such a reflecting surface is formed by flattening the first and second inner peripheral surfaces 6 and 8 by processing the frame 3 by a method such as cutting, die forming, polishing or the like. Can do. In particular, in order to increase the light reflection efficiency, a high-reflectance metal such as Al, Ag, gold (Au), platinum (Pt), titanium (Ti), chromium (Cr), or Cu is used as the frame 3 for cutting. It is preferable to form the first and second inner peripheral surfaces 6 and 8 by flattening them by processing, molding, polishing or the like.

  Alternatively, the reflecting surface is formed of Al, Ag, Au, etc. on the first and second inner peripheral surfaces 6 and 8 of the frame 3 made of Cu-W alloy, SUS alloy, or ceramics, which are excellent in weather resistance and moisture resistance. You may produce by forming metal thin films, such as metal plating of this, vapor deposition. When the reflecting surface is made of a metal that is easily discolored by oxidation such as Ag or Cu, low melting point glass or sol-gel glass having excellent transmittance from the ultraviolet region to the visible light region, a silicone resin, It is preferable to apply an epoxy resin, whereby the corrosion resistance, chemical resistance, and weather resistance of the first inner peripheral surface 6 and the second inner peripheral surface 8 of the frame 3 can be improved.

  The first inner peripheral surface 6 preferably has an arithmetic average roughness larger than that of the second inner peripheral surface 8. Thereby, the reflected light can be satisfactorily scattered on the first inner peripheral surface 6 to irradiate many phosphors with light, the wavelength conversion efficiency can be further increased, and the light traveling obliquely upward The second inner peripheral surface 8 can efficiently regularly reflect upward without irregular reflection to increase the directivity, and can further improve the emitted light intensity and directivity.

Further, the first and second inner peripheral surfaces 6 and 8 are set to 0.4 μm ≦ a ₁ ≦ 0.8 μm and a ₂ ≦ 0.1 μm when the arithmetic average roughnesses are a ₁ and a ₂ , respectively. Is preferred. For example, when Ra is 0.8 μm <a ₁ , irregular reflection of light occurs more than necessary on the first inner peripheral surface 6 of the frame 3 of the light emitting element 4, and light emitted to the outside of the frame 3 is likely to decrease. Become. In addition, when a ₁ <0.4 μm, the light is regularly reflected by the first inner peripheral surface 6, so that some phosphors are irradiated with strong light, and some phosphors are irradiated with light. Phenomenon is not likely to occur, and it is difficult to efficiently perform wavelength conversion with a phosphor. As a result, the propagation loss of light inside the light emitting device 1 increases, and it becomes difficult to efficiently emit light to the outside of the light emitting device 1.

In addition, when 0.1 μm <a ₂ , it is difficult to regularly reflect light on the second inner peripheral surface 8 of the frame 3 of the light emitting element 4, and it is easy to diffusely reflect inside the light emitting device 1. As a result, the propagation loss of light inside the light emitting device 1 tends to increase, and it becomes difficult to emit light outside the light emitting device 1 at a desired radiation angle.

  The transparent member 5 is filled with an inorganic or organic phosphor that is excited by light from the light emitting element 4 and emits blue, red, green, or the like by recombination of electrons. Thereby, the light which has a desired emission spectrum and color can be output by mix | blending a fluorescent substance in arbitrary ratios.

  The light-emitting element 4 uses a nitride semiconductor in which a buffer layer made of GaN, AlGaN, InGaN or the like, an n-type layer, a light-emitting layer, and a p-type layer are sequentially stacked on a sapphire substrate.

  The translucent member 5 is preferably made of a material having a small refractive index difference from the light emitting element 4 and having a high transmittance with respect to light in the ultraviolet region to the visible light region. For example, the translucent member 5 is made of a transparent resin such as a silicone resin, an epoxy resin, or a urea resin, a low-melting glass, a sol-gel glass, or the like. This effectively suppresses the occurrence of light reflection loss due to the difference in refractive index between the light emitting element 4 and the translucent member 5, and at the desired radiation intensity and angular distribution with high efficiency to the outside of the light emitting device 1. The light emitting device 1 that emits light can be manufactured.

  Thus, in the package of the present invention, the light emitting element 4 is mounted on the mounting portion 2a of the base 2, and the light emitting element 4 is connected to the external electric circuit board via the bonding wire (not shown) and the wiring conductor (not shown). After that, the phosphor or the translucent member 5 in which the phosphor is mixed is filled around the surface or the surface of the light-emitting element 4 and thermally cured. The light emitting device 1 can convert the light having a desired wavelength spectrum and extract the light from the light emitting surface 7.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention. For example, by joining a flat translucent lid to the upper surface of the frame 3 with solder, a resin adhesive, or the like, water resistance to the inside of the light emitting device 1 is improved and long-term reliability is improved.

It is sectional drawing which shows an example of embodiment of the light-emitting device of this invention. It is sectional drawing which shows the conventional light-emitting device.

Explanation of symbols

1: Light emitting device 2: Base 2a: Placement portion 3: Frame body 4: Light emitting element 5: Translucent member 6: First inner peripheral surface 7: Light emitting surface 8: Second inner peripheral surface

Claims (5)

A substrate;
A light emitting device mounted on the substrate;
A reflective member disposed on the base body and surrounding the light emitting element, and having a first reflective surface disposed on the base side and a second reflective surface disposed on the external side;
A light-transmitting light that includes a phosphor that converts the wavelength of light emitted from the light-emitting element, is provided inside the reflective member, and has a light-emitting surface positioned below the second reflective surface. Light-emitting device provided with a conductive member.   The light emitting device according to claim 1, wherein a first inclination angle of the first reflection surface is different from a second inclination angle of the second reflection surface.   The light emitting device according to claim 1, wherein the light emitting element is a light emitting diode made of a nitride semiconductor.   The light-emitting device according to claim 1, wherein the phosphor is excited by light emitted from the light-emitting element and emits blue, red, and green light.   The light-emitting device according to claim 1, wherein the translucent member is a thermosetting resin filled inside the reflective member.

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