JP4587675B2 - Light emitting element storage package and light emitting device - Google Patents

Description

  The present invention relates to a light emitting device that radiates light emitted from a light emitting element 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. 3, the light emitting device 11 includes a base 12 made of an insulator having a mounting portion 12a for mounting the light emitting element 14 at the center of the upper surface, and the outer surface of the light emitting device 11 from the mounting portion 12a and its periphery. And a wiring conductor (not shown) made of a lead terminal, which is electrically connected to the inside and outside of the light emitting device 11, and metallized wiring, and the like, and is bonded and fixed to the upper surface of the base 12, and the upper opening is lower than the lower opening. A frame 13 in which a large through-hole is formed and an inner peripheral surface is a reflection surface 16 that reflects light emitted from the light-emitting element 14, and a translucent member filled in the frame 13 15, a phosphor (not shown) that is contained in the translucent member 15 or is coated on the upper surface of the translucent member 15 and converts the light of the light-emitting element 14 to a long wavelength, and a mounting portion It is mainly composed of a light emitting element 14 mounted and fixed on 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 the lower opening is formed and a reflection surface 16 for reflecting light is provided on the 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, and extrusion molding. It is formed by.

  Further, the reflecting surface 16 of the frame 13 is formed by polishing and flattening, or by depositing a metal such as Al on the inner peripheral surface of the frame 13 by vapor deposition or plating. The frame 13 is bonded to the upper surface of the base 12 by a soldering material such as solder, silver (Ag) paste, or a bonding 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 17 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. An epoxy resin or silicone resin that does not contain a phosphor, or is filled in the frame 13 with a translucent member 15 such as silicone resin or the like so as to cover the light emitting element 14 with an injection machine such as a dispenser, or is thermally cured in an oven. After filling the inside of the frame 13 with a translucent member 15 such as a dispenser so as to cover the light emitting element 14 with an injection machine such as a dispenser and thermally curing it in an oven, the upper surface thereof is coated with a phosphor, thereby the light emitting element The light from 14 can be converted into a longer wavelength side by a phosphor to form a light emitting device 11 having a desired wavelength spectrum.
JP-A-10-107325

  However, in the conventional light emitting device 11, light emitted upward or laterally from the light emitting element 14 is directly or directly reflected by the reflecting surface 16 of the frame 13, and is emitted to the outside. The light emitted in the downward direction is repeatedly reflected between the base 12 and the light emitting element 14, and is absorbed and attenuated by the base 12 and the adhesive 17 without being emitted to the outside. In addition, the problem is that the emitted light intensity is low.

  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 with high radiated light intensity that can efficiently emit light from a light emitting element to the outside. It is in.

The light emitting element storage package according to the present invention includes a translucent submount in which a light emitting element placement portion is formed on an upper main surface, a base on which the submount is placed in a central portion on an upper surface, and the base A frame body joined to surround the submount, the inner peripheral surface of which is a reflective surface that reflects the light emitted from the light emitting element, and between the base and the submount, A phosphor layer containing a phosphor that is provided in a region overlapping with the light emitting element and is excited by light emitted from the light emitting element, and the submount receives light emitted from the light emitting element. made of a translucent material entering, the arithmetic mean of the upper side main surface of the arithmetic average roughness of the lower principal surface of the submount so as to scatter a portion of the light that has entered into the sub-mount the submount greater than the roughness was this The features.

  In the light emitting element storage package of the present invention, preferably, the submount has an arithmetic mean roughness of an upper main surface of 0.1 μm or less.

In the light emitting element storage package according to the present invention, preferably, the phosphor layer is formed with a light reflecting layer on a lower main surface thereof.

  The light-emitting device of the present invention includes the light-emitting element storage package of the present invention, a light-emitting element placed on the mounting portion via a translucent adhesive, and the light-emitting element inside the frame. And a translucent member provided so as to cover it.

  In the light emitting device of the present invention, preferably, the adhesive has a refractive index equal to or smaller than a refractive index of the submount.

  The light emitting element storage package of the present invention includes a translucent submount in which a light emitting element mounting portion is formed on an upper main surface, a base on which the submount is mounted in a central portion of an upper surface, A frame body, the inner peripheral surface of which is joined so as to surround the submount and the inner peripheral surface of which is a reflective surface that reflects the light emitted from the light emitting element, and the submount is an arithmetic average of the upper main surface Since the roughness is smaller than the arithmetic average roughness of the lower main surface, the light emitted from the light emitting element in the lower direction is transmitted through the translucent submount well, and the submount having a large arithmetic average roughness is used. By irregularly reflecting on the lower main surface, it is possible to effectively prevent light from being attenuated by repeating reflection between the light emitting element and the substrate, and to efficiently extract the light to the outside. To increase the intensity of synchrotron radiation It can be.

  In addition, when a phosphor for wavelength conversion of light emitted from the light emitting element is provided so as to cover the light emitting element, light is uniformly irradiated to the entire phosphor by irregularly reflecting the lower main surface of the submount. Therefore, it is possible to effectively prevent the wavelength conversion efficiency of the phosphor from being lowered by irradiating only a part of the phosphors with light, and to significantly improve the wavelength conversion efficiency.

  In the light emitting element storage package of the present invention, it is preferable that the submount has an arithmetic mean roughness of the upper main surface of 0.1 μm or less, so that light emitted from the light emitting element in the lower direction is transmitted to the upper side of the submount. The light can be transmitted well without being scattered on the main surface, and the radiation efficiency can be further improved by suppressing the attenuation of light between the light emitting element and the submount very well.

  In the light emitting element storage package of the present invention, preferably, since the light reflecting layer is formed on the lower main surface of the submount, the light emitted from the light emitting element in the lower direction is favorably reflected. And the emitted light intensity of the light emitting device can be further improved.

  In the light emitting element storage package of the present invention, preferably, the submount is emitted in the lower direction from the light emitting element because the phosphor layer and the light reflecting layer are sequentially formed on the lower main surface thereof. The wavelength of light can be efficiently converted by the phosphor layer on the lower side of the submount, and light having an arbitrary color can be emitted more efficiently.

  Further, it is possible to irradiate the phosphor layer uniformly with light scattered on the lower main surface of the submount, and the wavelength conversion efficiency of the phosphor layer can be increased.

  In addition, the wavelength-converted light is efficiently reflected by reflecting the light, which has been wavelength-converted by the phosphor layer under the submount, by the light-reflecting layer under the phosphor layer and scattering it from the bottom surface of the submount. It can be taken out well and can have a very high intensity of radiated light having a desired wavelength spectrum.

  The light-emitting device of the present invention is provided with the above-described light-emitting element storage package of the present invention, a light-emitting element mounted on the mounting portion via a light-transmitting adhesive, and a light-emitting element covering the inside of the frame. A light emitting device with high radiated light intensity that can efficiently extract the light of the light emitting element using the light emitting element storing package of the present invention to the outside of the package. It can be.

  In the light emitting device of the present invention, it is preferable that the adhesive has a refractive index that is the same as that of the submount or smaller than that of the submount. It is possible to effectively prevent total reflection from occurring at the interface between the agent and the submount, and to efficiently transmit the submount, and to extract light from the light emitting element very efficiently.

  The light emitting element storage package (hereinafter also simply referred to as a package) 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 package of the present invention. In FIG. 1, 2 is a base, 3 is a frame, 8 is a submount, and 9 is a light reflecting layer. These packages are mainly configured, and the light emitting element 4 is attached to the submount 8 of this package via an adhesive 7. The light emitting device 1 is obtained by placing the light transmissive member 5 inside the frame 3 so as to cover the light emitting element 4.

  The package of the present invention includes a translucent submount 8 in which the mounting portion 8a of the light emitting element 4 is formed on the upper main surface, a base 2 on which the submount 8 is mounted in the center of the upper surface, and a base 2 And a frame body 3 having an inner peripheral surface which is joined to surround the submount 8 and is a reflecting surface 6 for reflecting light emitted from the light emitting element 4.

  The submount 8 of the present invention is made of an inorganic compound such as sapphire or glass, a transparent resin, or the like, and transmits light emitted from the light emitting element 4 satisfactorily.

Preferably, the submount 8 is made of sapphire. Thereby, the thermal expansion coefficients of the light emitting element 4 and the submount 8 can be matched, and failure such as cracking of the light emitting element 4 caused by stress generated by the heat generated by the light emitting element 4 and peeling from the substrate 2 can be suppressed. Or it can be reduced. For example, when the light emitting element 4 is made of a gallium nitride compound semiconductor, the thermal expansion coefficient is 5.59 × 10 ⁻⁶ K ⁻¹ , and when the light emitting element 4 is made of a gallium arsenide compound semiconductor, the thermal expansion coefficient is 5.7 × 10 ⁻⁶ K ^−. Whereas it is ¹ , the thermal expansion coefficient of sapphire is 6.7 × 10 ⁻⁶ K ⁻¹ , and the difference in thermal expansion coefficient between the light emitting element 4 and the submount 8 can be made very small.

  Furthermore, since sapphire has a heat conductivity of 27 J / m · s · ° C. and excellent heat dissipation, heat generated from the light-emitting element 4 can be transferred to the substrate 2 effectively to effectively suppress the temperature rise of the light-emitting element 4. Therefore, it is possible to effectively suppress the lattice distortion existing in the light emitting element 4 from being increased by the heat generated in the light emitting element 4. As a result, deterioration of the light emission efficiency of the light emitting element 4 can be effectively suppressed.

  In the submount 8 of the present invention, the arithmetic average roughness of the upper main surface is smaller than the arithmetic average roughness of the lower main surface. Thereby, light emitted from the light emitting element 4 in the lower direction is transmitted through the translucent submount 8 and diffusely reflected on the lower main surface of the submount 8 having a large arithmetic average roughness, thereby emitting light. By repeating the reflection between the element 4 and the substrate 2, it is possible to effectively prevent the light from being attenuated, and the light can be efficiently extracted to the outside. Can be high. Further, when the phosphor for converting the wavelength of light emitted from the light emitting element 4 is provided so as to cover the light emitting element 4 by a method such as containing the light transmitting member 5, the lower main part of the submount 8. By irregularly reflecting on the surface, it is possible to irradiate light uniformly over the entire phosphor, effectively preventing only a part of the phosphor from being irradiated with light and reducing the wavelength conversion efficiency of the phosphor, Wavelength conversion efficiency can be significantly improved.

  The arithmetic average roughness of the lower main surface of the submount 8 is preferably 4 to 10 times the arithmetic average roughness of the upper main surface. Thereby, the light emitted in the downward direction from the light emitting element 4 can be taken out very efficiently to the outside, and the radiation efficiency of the light emitting device 1 can be increased to increase the emitted light intensity extremely.

  The submount 8 preferably has an arithmetic average roughness of the upper main surface of 0.1 μm or less. As a result, light emitted downward from the light emitting element 4 can be transmitted well without being scattered by the upper main surface of the submount 8, and light is attenuated between the light emitting element 4 and the submount 8. Therefore, it is possible to improve radiation efficiency more effectively.

  The arithmetic average roughness of the upper and lower main surfaces of the submount 8 can be set to a desired value by a method such as polishing or etching.

  The submount 8 preferably has a light reflecting layer 9 formed on the lower main surface thereof. Thereby, the light emitted in the downward direction from the light emitting element 4 can be favorably reflected, and the emitted light intensity of the light emitting device 1 can be further improved.

  The light reflecting layer 9 can efficiently reflect the light emitted from the light emitting element 4, and examples thereof include a material having a high light reflectance such as a metal such as aluminum or silver, or a ceramic such as white. It is done. More preferably, it is a metal having a high light reflectivity and a high thermal conductivity. When the light reflecting layer 9 is made of metal, the lower main surface of the submount 8 is dispersed by a method such as vapor deposition, plating, metallization, brazing, or the powdered metal that becomes the light reflecting layer 9 in an organic solvent. It can be manufactured by a method in which the organic solvent is removed after applying the object to the lower main surface of the submount 8.

  In addition, as shown in FIG. 2, the submount 8 is preferably formed with a phosphor layer 10 and a light reflecting layer 9 sequentially formed on the lower main surface thereof. Thereby, the light emitted from the light emitting element 4 in the lower direction can be efficiently wavelength-converted by the phosphor layer 10 on the lower side of the submount, and light having an arbitrary color can be emitted more efficiently. it can.

Moreover, it is possible to irradiate the phosphor layer 10 uniformly with light scattered on the lower main surface of the submount 8, and to increase the wavelength conversion efficiency of the phosphor layer 10 .

Further, the light whose wavelength is converted by the lower phosphor layer 10 of the submount 8, by scattering at the lower surface of the submount 8 is reflected by the light reflecting layer 9 on the lower side of the phosphor layer 10, the wavelength conversion by light can be efficiently extracted to the outside has, it is assumed very high emitted light intensity having a desired wavelength spectrum.

  Such a phosphor layer 10 is excited by light from the light-emitting element 4 on a translucent member made of, for example, a transparent resin such as silicone resin, epoxy resin, or urea resin, low-melting glass, sol-gel glass, or the like. Those containing inorganic or organic phosphors that emit blue, red, green, etc. light upon recombination.

  The submount 8 is bonded to the upper surface of the base 2 via a bonding material such as a resin adhesive or a brazing material. When the light reflecting layer 9 is formed on the lower main surface of the submount 8, a known resin adhesive, brazing material, or the like is used as a bonding material for bonding the submount 8 and the substrate 2. Further, when the light reflecting layer 9 is not formed on the lower main surface of the submount 8, the submount 8 is transmitted through the submount 8 by making the bonding material for bonding the submount 8 and the base 2 light-reflective. The reflected light can be reflected well by the bonding material. As such a light-reflective bonding material, a transparent resin containing metal particles or ceramic particles having high light reflectance can be used.

  The submount 8 is made of the same material as that of the substrate constituting the lower part of the light emitting element 4 or a member whose thermal expansion coefficient and refractive index are matched with those of the substrate constituting the lower part of the light emitting element 4. It is preferable to use it. Thereby, the refractive index of the substrate constituting the lower part of the light emitting element 4 and the refractive index of the submount 8 can be matched, light from the lower surface of the light emitting element 4 can be taken out efficiently, and thermal expansion with the light emitting element 4 can be achieved. Coefficients can be matched, and failures such as cracks in the light emitting element 4 caused by stress generated by heat generated by the light emitting element 4 and peeling from the submount 8 can be suppressed or reduced. Furthermore, it is possible to effectively suppress an increase in lattice distortion of the light emitting element 4 and to reduce deterioration in light emission efficiency.

The adhesive 7 for mounting and fixing the light emitting element 4 on the submount 8 is translucent. Preferably, the adhesive 7 is equal to or smaller than the refractive index of the submount 8. Thereby, it is possible to effectively prevent the light emitted from the light emitting element 4 in the downward direction from being totally reflected at the interface between the adhesive 7 and the submount 8 and efficiently transmit the light through the submount 8. Light from the light emitting element 4 can be extracted very efficiently. That is, assuming that the refractive index of the adhesive 7 is n ₁ and the refractive index of the submount 8 is n ₂ , total reflection may occur at the interface between the submount 8 and the adhesive 7 if n ₁ > n _2. It becomes high and luminous efficiency falls easily.

Preferably, the adhesive 7 has the same refractive index as that of the substrate constituting the lower part of the light emitting element 4 or higher than that of the substrate constituting the lower part of the light emitting element 4. Thereby, it is possible to effectively prevent the light emitted downward from the light emitting element 4 from being totally reflected at the interface between the adhesive 7 and the substrate of the light emitting element 4 and efficiently transmit the adhesive 7. The light from the light emitting element 4 can be extracted very efficiently. That is, the refractive index of the adhesive 7 n _1, the refractive index of the substrate of the lower portion of the light-emitting element 4 when the n _3, at the interface of n 1 _{<n 3} If the light emitting element 4 and the adhesive 7 The possibility that total reflection occurs increases, and the light emission efficiency tends to decrease.

  The substrate 2 is made of ceramics such as alumina ceramics, aluminum nitride sintered bodies, mullite sintered bodies, glass ceramics, metals such as Fe-Ni-Co alloys and Cu-W, or resins such as epoxy resins. Become.

  The frame 3 is made of ceramics such as alumina ceramics, aluminum nitride sintered bodies, mullite sintered bodies, glass ceramics, metals such as aluminum, silver, Fe-Ni-Co alloys, Cu-W, or epoxy. It consists of resin such as resin. The frame 3 is bonded to the base 2 by a bonding material such as a brazing material or a resin adhesive.

  Further, the inner peripheral surface of the frame 3 is a reflecting surface 6. When the frame 3 is made of a highly reflective metal, the reflective surface 6 has the inner peripheral surface made the reflective surface 6 by forming the frame 3 by pressing, cutting, casting, or the like. It is produced in a state. Alternatively, it can be formed by depositing a metal having a high reflectance on the inner peripheral surface of the frame 3 by plating or vapor deposition.

  Furthermore, the reflective surface 6 of the frame 3 preferably has an arithmetic average roughness Ra of the surface of 0.1 μm or less, so that the light of the light emitting element 4 can be favorably reflected to the upper side of the light emitting device 1. . When Ra exceeds 0.1 μm, it is difficult for regular reflection of light by the reflection surface 6 of the frame 3 of the light emitting element 4 and random reflection within the light emitting device 1. As a result, the propagation loss of light inside the light emitting device 1 tends to be large, and it becomes difficult to emit light to the outside of the light emitting device 1 at a desired radiation angle.

  Also. 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. Thereby, it is possible to effectively suppress 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 to achieve a desired radiation intensity with high efficiency outside the light emitting device 1. The light emitting device 1 capable of emitting light with an angular distribution can be manufactured. As such a translucent member 5, it consists of transparent resin, such as a silicone resin, an epoxy resin, and a urea resin, low melting glass, sol-gel glass, etc., for example.

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

  For example, the light emitting element 4 is formed by sequentially stacking a buffer layer, an n-type layer, a light-emitting layer, and a p-type layer made of a semiconductor such as GaN, AlGaN, InGaN, or GaAs on a sapphire substrate.

  Thus, the package and the light emitting device 1 of the present invention are provided in the package by mounting the light emitting element 4 on the mounting portion 8a of the submount 8 and by wire bonding or flip chip mounting using solder balls. The light emitting element 4 and the external electric circuit board are electrically connected by being electrically connected to a wiring conductor (not shown) made of a lead terminal, metallized wiring or the like that electrically connects the inside and outside of the light emitting device 1. It can be made to conduct. Then, the phosphor or the translucent member 5 in which the phosphor is mixed is filled around and on the surface of the light-emitting element 4 and cured by heat or the like, so that the wavelength of the light of the light-emitting element 4 is converted by the phosphor to a desired wavelength spectrum. Thus, the light emitting device 1 capable of extracting light having a light intensity is obtained.

  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, an optical lens capable of arbitrarily condensing or diffusing light emitted from the light emitting element 4 on the upper surface of the frame body 3, or a flat translucent lid body with solder or adhesive By joining, light can be emitted at a desired radiation angle, and the water resistance to the inside of the light emitting device 1 is improved, and long-term reliability is improved.

  Further, the inner peripheral surface of the frame 3 may have a flat (straight) cross-sectional shape, or may have a curved shape such as an arc shape. In the case of the circular arc shape, the light of the light emitting element 4 can be uniformly reflected, and light with high directivity can be uniformly emitted to the outside.

  Furthermore, although the example which covered the light emitting element 4 with the translucent member 5 with which the inner side of the frame 3 was filled was shown, the translucent member 5 is made into a plate-shaped member so that the upper surface of the frame 3 may be covered with the light emitting element 4. May be attached to.

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 other 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 body 3: Frame body 4: Light-emitting element 6: Reflecting surface 7: Adhesive 8: Submount 8a: Mounting portion 9: Light reflecting layer

Claims (5)

A translucent submount having a light emitting element mounting portion formed on the upper main surface;
A base on which the submount is placed at the center of the upper surface;
A frame body that is joined to the upper surface of the substrate so as to surround the submount, and whose inner peripheral surface is a reflective surface that reflects the light emitted from the light emitting element ;
A phosphor layer provided between the substrate and the submount and in a region overlapping with the light emitting element, and containing a phosphor excited by light emitted from the light emitting element ,
The submount is made of a translucent material into which light emitted from the light emitting element enters, and the arithmetic average roughness of the lower main surface of the submount is scattered so as to scatter a part of the light that has entered the submount. package for housing a light-emitting element, characterized in that larger than the arithmetic mean roughness of the top side main surface of the submount.   2. The light emitting element storage package according to claim 1, wherein the submount has an arithmetic mean roughness of an upper main surface of 0.1 μm or less. 3. The light emitting element storage package according to claim 1, wherein a light reflecting layer is formed on a lower main surface of the phosphor layer . The light emitting element storage package according to any one of claims 1 to 3 , the light emitting element placed on the placement portion via a light-transmitting adhesive, and the light emission inside the frame body A light-emitting device comprising: a light-transmitting member provided to cover the element. The light emitting device according to claim 4 , wherein the adhesive has a refractive index equal to or smaller than a refractive index of the submount.

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