JP2013038215A - Wavelength conversion member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion member which accurately and easily adjusts the thickness of a phosphor layer and is excellent in heat radiation performance, which is combined with an LED element fitted in the wavelength conversion member to control the luminescent color and the luminance of a light emitting device and which improves the yield of the light emitting device.SOLUTION: A wavelength conversion member includes: a pair of heat radiation translucent plates which are provided so as to face each other; a spacer disposed between the pair of heat radiation translucent plates; and a phosphor layer including a phosphor formed in a space closed by the pair of heat radiation translucent plates and the spacer.

Description

  The present invention relates to a wavelength conversion member used for a light emitting device including an LED element.

  Conventionally, a light emitting device that emits light of a color different from that of LED elements such as white by combining blue light or ultraviolet light emitting LED elements and various phosphors using a gallium nitride compound semiconductor 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. In particular, recently, LED elements with high output and high brightness have been developed, and their uses are increasingly expanding.

  Such a light-emitting device includes a wavelength conversion member containing a phosphor. For example, the wavelength conversion member includes a transparent resin for sealing an LED element in a concave portion of a base on which the LED element is mounted. After filling and curing, it is formed by injecting a resin composition in which a phosphor is dispersed.

  At this time, since the emission color (color temperature) of the light emitting device changes when the thickness of the wavelength conversion member changes, it is extremely important to control and manage the thickness of the wavelength conversion member.

  In addition, the resin composition in which the phosphor is dispersed is usually prepared by temporarily preparing an amount corresponding to a plurality of light emitting devices, and then injecting the predetermined amount. The phosphor in the resin composition Since the dispersion state changes with time, even in the light emitting devices of the same lot, there are slight variations in the color of the emitted color and the illuminance. Moreover, there are variations in the emission color and illuminance of the LED elements, and this also causes variations in the emission color and illuminance of the light emitting device as the final product. However, when the obtained light-emitting device is used as a light source for an inspection apparatus, even if there is even a slight variation, the reliability of the inspection result is impaired, and the influence is significant.

  Furthermore, the phosphor used in such a light-emitting device is vulnerable to heat, and is thermally deteriorated due to the heat generated by the phosphor itself or the heat transfer from the LED element. When the output of the LED element is increased, the amount of generated heat is also increased. Therefore, in recent years when the output of the LED element is increased, there is an urgent need to solve the decrease in luminous efficiency and luminance of the phosphor due to thermal degradation.

JP 2005-191197 A

  The present invention has been made in view of such a problem, and the thickness of the fluorescent layer can be adjusted accurately and easily, and it has excellent heat dissipation. An object of the present invention is to provide a wavelength conversion member that can control the illuminance and increase the yield of the light emitting device.

  That is, the wavelength conversion member according to the present invention includes a pair of heat radiating light transmitting plates provided to face each other, a spacer interposed between the pair of heat radiating light transmitting plates, the pair of heat radiating light transmitting plates, and the And a fluorescent layer containing a phosphor formed in a space closed by a spacer.

  If it is such, since the distance between two heat-radiating translucent plates can be determined by the spacer, the thickness of the fluorescent layer formed between them can be controlled and managed accurately and easily. . For this reason, it becomes possible to manage the emission color (color temperature) of the light emitting device with good reproducibility.

  In addition, according to the present invention, since the heat of the fluorescent layer can be efficiently released through the two heat dissipating transparent plates surrounding the fluorescent layer and the spacer, the phosphor included in the fluorescent layer It is possible to effectively prevent thermal deterioration such as a decrease in luminous efficiency and luminance.

  Further, according to the present invention, since the wavelength conversion member is prepared in advance and the light emitting device is assembled by combining the wavelength conversion member and the LED element, the wavelength and the light intensity are set in advance, for example, near ultraviolet rays are emitted. Using a reference light source, measure the emission color, illuminance, etc. of the wavelength conversion member, classify and manage a group of wavelength conversion members with variations according to the emission color, illuminance, etc., and have the desired emission color, illuminance, etc. A light emitting device having a desired performance can be manufactured by selecting and combining with a suitable LED element. For this reason, it is possible to suppress variations in the emission color, illuminance, and the like of the obtained light emitting device as much as possible.

  The spacer may be integrated with at least one of the heat radiating light transmitting plates. Such a heat-radiating light-transmitting plate has, for example, a recess, and a fluorescent layer can be formed by filling a resin composition in which a phosphor is dispersed therein.

  One of the pair of heat-radiating light-transmitting plates is preferably a long-wavelength transmission filter that reflects ultraviolet rays and short-wavelength visible rays and transmits longer-wavelength visible rays. A long wavelength transmission filter is used for one of the pair of heat radiating light transmission plates, and after assembling the light emitting device, a wavelength conversion member is installed so that the long wavelength transmission filter is located on the light emission surface side, thereby providing an LED element. The ultraviolet rays and short-wavelength visible light emitted from the light and not hitting the phosphor are reflected back to the fluorescent layer side by the long-wavelength transmission filter, and the conversion efficiency into long-wavelength visible light can be improved. In addition, by using a long wavelength transmission filter, harmful near ultraviolet light can be prevented from being emitted outside the light emitting device, and the dielectric multilayer film of the long wavelength transmission filter also functions as an antireflection coating. In addition, visible light having a long wavelength can be efficiently led out of the apparatus.

  The light emitting device obtained by combining the wavelength conversion member and the LED element according to the present invention is also one aspect of the present invention.

  When the light emitting device according to the present invention includes a base body that supports the wavelength conversion member, the spacer and the base body may be integrated.

  According to the present invention having such a configuration, the thickness of the fluorescent layer that affects the emission color (color temperature) of the light emitting device can be easily adjusted with high accuracy. Moreover, according to this invention, the change of the fluorescent substance by a heat | fever can also be suppressed favorably. Furthermore, according to the present invention, by classifying and managing the obtained wavelength conversion member and using it in combination with a suitable LED element, it is easy to control the emission color and illuminance of the light-emitting device, and suppresses variation and high yield. A light emitting device can be manufactured.

It is a longitudinal cross-sectional view of the light-emitting device which concerns on one Embodiment of this invention. It is a top view of the light-emitting device concerning the embodiment. It is a graph which shows the outline | summary of the transmittance | permeability and reflectance of the long wavelength transmission filter in the embodiment. It is a figure which shows the manufacturing process (a)-(c) of the wavelength conversion member in the embodiment. It is a figure which shows the manufacturing process (d)-(f) of the wavelength conversion member in the embodiment. It is a figure which shows the manufacturing process (a)-(b) of the light-emitting device based on the embodiment. It is a figure which shows the manufacturing process (c)-(d) of the light-emitting device concerning the embodiment. It is a longitudinal cross-sectional view of the light-emitting device which concerns on other embodiment. It is a longitudinal cross-sectional view of the light-emitting device which concerns on other 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 this embodiment includes an LED element 3, a sealing member 4 that seals the LED element 3, and a wavelength conversion provided above the sealing member 4. The LED element 3, the sealing member 4, and the wavelength conversion member 5 are accommodated and held in the base 2.

Each part is described in detail below.
The base body 2 has a concave portion opened at the upper end surface, and examples thereof include those formed by molding an insulating material having a high thermal conductivity such as alumina or aluminum nitride.

  An annular ridge portion 21 is formed on the side surface of the concave portion of the base 2, and the wavelength conversion member 5 is placed on the upper end surface of the ridge portion 21. As shown in FIG. 2, the recesses of the base 2 are formed with chamfering holes 22 at the four corners so that the corners do not interfere when the wavelength conversion member 5 is fitted into the recesses. is there. Also, a metal thin film with high reflectivity is formed on the inner surface including the side surface and the bottom surface of the concave portion of the base 2 by applying metal plating such as silver, aluminum, gold, etc., and functions as a reflector. . Then, ultraviolet rays or short-wavelength visible rays reflected downward by the upper heat radiating light transmitting plate 53 made of a long wavelength transmission filter and transmitted through the fluorescent layer 52 and the lower heat radiating light transmitting plate 51 are reflected by the metal thin film. Again, it can be reflected toward the fluorescent layer 52.

  The LED element 3 emits ultraviolet rays or short-wavelength visible light, and has a radiation peak at 360 to 430 nm, for example. Such an LED element 3 is formed, for example, by laminating a gallium nitride compound semiconductor in the order of an n-type layer, a light emitting layer, and a p-type layer on a sapphire substrate or a gallium nitride substrate.

  The LED element 3 is flip-chip mounted on the substrate 31 using solder bumps, gold bumps or the like (not shown) with the gallium nitride compound semiconductor facing down. The LED element 3 may be connected to a wiring conductor provided on the substrate 31 using wire bonding. In the present embodiment, a plurality (9) of LED elements 3 are mounted. However, the number of LED elements 3 is not limited to this, and can be appropriately changed according to the purpose and application.

  The substrate 31 is made of an insulating material having high thermal conductivity such as ceramics such as alumina or aluminum nitride. For example, a silver pattern for electrically connecting the LED element 3 to the upper surface of the substrate 31 is used. A wiring conductor (not shown) 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 body 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.

  The sealing member 4 is for sealing the LED element 3. In order to efficiently extract light from the LED element 3 to the sealing member 4, the sealing member 4 is excellent in translucency and heat resistance, and the LED element 3. The refractive index difference is preferably made of a transparent resin such as a silicone resin.

  The wavelength conversion member 5 is a laminated body in which a fluorescent layer 52 is sandwiched between a lower heat transmissive plate 51 and an upper heat transmissive plate 53 together with a spacer S.

  The fluorescent layer 52 contains the fluorescent substance 521 inside. For example, the fluorescent substance 521 is contained in a matrix made of a silicone resin, a fluororesin, a low-melting glass, etc. having excellent translucency and heat resistance. Examples are dispersed.

  The phosphor 521 contained in the phosphor layer 52 is not particularly limited, and examples thereof include a red phosphor, a green phosphor, a blue phosphor, and a yellow phosphor. Among these, when the red phosphor, the green phosphor, and the blue phosphor are used in combination, the light emitting device 1 that emits white light can be configured.

  The spacer S is made of a metal having high thermal conductivity such as copper or aluminum, and has a flat plate shape provided with a through hole S1 for forming the fluorescent layer 52.

  The lower heat-radiating light-transmitting plate 51 is disposed below the fluorescent layer 52 and is made of a material having high heat conductivity and excellent light-transmitting properties such as crystal, sapphire, diamond, and aluminum nitride. . The lower heat radiating translucent plate 51 made of such a material secures translucency by evaporating, for example, a metal having excellent thermal conductivity such as copper or aluminum on the surface thereof in a line shape or a lattice shape. However, the thermal conductivity can be further improved.

  The upper heat dissipating translucent plate 53 is a long wavelength transmission filter (high pass filter) that reflects ultraviolet rays and short wavelength visible rays and selectively transmits long wavelength visible rays, and is superimposed on the fluorescent layer 52. Is provided. As such an upper heat dissipating light transmitting plate 53, for example, as shown in FIG. 3, the one having a dielectric multilayer film in which the light reflectance and transmittance are reversed with the vicinity of 430 nm as a boundary is used. Can do. Such a dielectric multilayer film is formed, for example, by attaching a film material to a substrate made of glass, quartz, sapphire, or the like. The upper heat dissipating translucent plate 53 may be arranged so that either side of the surface is in contact with the fluorescent layer 52, for example, a substrate side surface (a surface on which the dielectric multilayer film is not formed). By disposing the upper heat radiating light transmitting plate 53 so as to be in contact with the fluorescent layer 52, the dielectric multilayer film of the upper heat radiating light transmitting plate 53 also functions as an anti-reflection coating, so that long wavelength visible light is efficiently used. Can be derived externally. In this case, if the substrate of the dielectric multilayer film is made of a material having excellent thermal conductivity such as quartz or sapphire, the heat generated from the fluorescent layer 52 (phosphor 521) is efficiently applied to the base 2. It can also be transmitted to the outside of the light emitting device 1. In addition, as described above, metal with excellent thermal conductivity such as copper and aluminum is deposited on the surface of the substrate in a line shape or a lattice shape, thereby improving the thermal conductivity of the substrate while ensuring translucency. Can be made. However, for example, if attention is paid to the heat dissipation of the dielectric multilayer film, the surface on which the dielectric multilayer film is formed may be in contact with the fluorescent layer 52.

  In such a light-emitting device 1, ultraviolet rays or short-wavelength visible rays that have passed through the fluorescent layer 52 without hitting the phosphor 521 are reflected by the upper heat-transmitting light-transmitting plate 53, and again pass through the fluorescent layer 52. proceed. For this reason, since the probability that ultraviolet rays or short-wavelength visible light hits the phosphor 521 is improved, more ultraviolet rays or short-wavelength visible light is converted into long-wavelength visible light, and as a result, light emission from the light emitting device 1 The amount increases. Further, among the long-wavelength visible light emitted from the phosphor 521, the backward light traveling toward the LED element 3 is reflected by the reflector (metal thin film) formed on the inner surface of the concave portion of the substrate 2 to change the traveling direction. Then, the light passes through the upper heat radiating light-transmitting plate 53, passes through the light-emitting device 1, and is emitted to the outside of the light emitting device 1, so that the extraction efficiency of visible light having a long wavelength is also improved. For this reason, according to the light emitting device 1, ultraviolet rays and short-wavelength visible light can be efficiently converted into long-wavelength visible light, and the converted visible light can be efficiently taken out of the light-emitting device 1. it can.

  Moreover, although the silicone resin etc. which comprise the sealing member 4 and the fluorescent layer 52 have a high gas permeability, in this embodiment, the upper heat-radiating light-transmitting plate 53 suppresses the entry of gas and moisture into the recesses of the base 2. Therefore, corrosion of the metal thin film formed on the inner surface of the concave portion of the base 2 due to oxidation, sulfurization, chlorination, or the like can be prevented.

  Next, a method for manufacturing the light emitting device 1 according to the present embodiment will be described with reference to FIGS.

  When manufacturing the light emitting device 1 according to this embodiment, the wavelength conversion member 5 is prepared in advance.

  First, a large number of through-holes having a size corresponding to a plurality of spacers S are formed on a large substrate having a size corresponding to a plurality of lower heat-transmitting light-transmitting plates 51 (or upper heat-transmitting light-transmitting plates 53). The metal plates provided with S1 are stacked and arranged (FIG. 4A). Here, when the wavelength conversion member 5 is disposed on the upper end surface of the protruding portion 21 by the spacer S, the upper end surface of the base 2 and the upper surface of the upper heat radiating light transmitting plate 53 are substantially flush with each other. Further, the height of the wavelength conversion member 5 is adjusted.

  Next, a predetermined amount of the resin composition 52 in which the phosphor 521 is dispersed is filled in the through-hole S1 (FIGS. 4B to 4C).

  After that, a large substrate having a size corresponding to a plurality of upper heat radiating light transmitting plates 53 (or lower heat radiating light transmitting plates 51) is placed on the spacer S in an overlapping manner (FIG. 5D).

  Then, if necessary, the resin composition 52 is cured by heating or the like, whereby the fluorescent layer 52 is sandwiched together with the spacer S between the lower heat transmissive plate 51 and the upper heat transmissive plate 53. A laminate in which a plurality of wavelength conversion members 5 are integrated can be obtained (FIG. 5E).

  A plurality of wavelength conversion members 5 can be produced at one time by cutting the laminate in which the plurality of wavelength conversion members 5 obtained in this way are integrated and separating one by one (FIG. 5). (F)).

  And the light-emitting device 1 which concerns on this embodiment is assembled as follows using the obtained wavelength conversion member 5. FIG.

  First, as shown in FIGS. 6A to 6B, the transparent resin 4 is filled in the concave portion of the base body 2 so as to bulge from the upper end surface of the protrusion 21. Thereafter, as shown in FIGS. 7C to 7D, the wavelength conversion member 5 prepared in advance is disposed on the upper end surface of the protrusion 21 so that the peripheral edge thereof is placed. Then, the overflowing transparent resin 4 oozes out between the upper end surface of the protruding portion 21 and the lower surface of the wavelength conversion member 5 and functions as an adhesive that bonds the base 2 and the wavelength conversion member 5 together.

  According to the light emitting device 1 according to the present embodiment, since the distance between the lower and upper heat transmissive plates 51 and 53 is determined by the spacer S, the thickness of the fluorescent layer 52 formed therebetween is reduced. Easy to control and manage with high accuracy. For this reason, the light emission color (color temperature) of the light emitting device 1 can be managed with good reproducibility.

  In the present embodiment, since the fluorescent layer 52 is formed in a space closed by the lower and upper heat-transmitting light-transmitting plates 51 and 53 and the spacer S, the spacer S and the lower and upper heat-transmitting transparent plates are formed. The heat generated from the fluorescent layer 52 can be efficiently transmitted to the substrate 2 through the optical plates 51 and 53 and released. For this reason, it is possible to effectively prevent thermal degradation such as a decrease in luminous efficiency and luminance of the phosphor 521 included in the phosphor layer 52.

  Furthermore, in this embodiment, since the wavelength conversion member 5 is manufactured as a separate body from the base 2 on which the LED element 3 is mounted, the light emitting device 1 is manufactured by combining them, so a reference light source is used. Analyzing the emission color, illuminance, etc. of the wavelength conversion member 5, classifying and managing a group of wavelength conversion members 5 with variations according to the emission color, illuminance, etc., selecting those having the desired emission color, illuminance, etc. By combining with a suitable LED element 3, it is possible to obtain the light emitting device 1 having the expected performance.

  The present invention is not limited to the above embodiment.

  For example, as shown in FIG. 8, the spacer S is integrated with the lower or upper heat-transmitting light-transmitting plates 51 and 53, and the lower or upper heat-transmitting light-transmitting plates 51 and 53 are formed with recesses. The side peripheral wall surrounding the recess may function as the spacer S. In the embodiment shown in FIG. 8, the spacer S is integrated with the lower heat radiating light transmitting plate 51, but may be integrated with the upper heat radiating light transmitting plate 53.

  Further, as shown in FIG. 9, the spacer S may be integrated with the base body 2, and a protrusion that functions as the spacer S may be formed on the inner peripheral surface of the recess of the base body 2. Further, the base 2 may be divided into a lower base 2A on which the LED element 3 is mounted and an upper base 2B that holds the wavelength conversion member 5.

  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.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device 2 ... Base | substrate 3 ... LED element 4 ... Sealing member 5 ... Wavelength conversion member 51 ... Lower heat-radiating translucent plate 52 ... Fluorescent layer 53 ...・ Upper heat transmissive translucent plate S ・ ・ ・ Spacer

Claims (5)

A pair of heat-dissipating translucent plates provided opposite to each other;
A spacer interposed between the pair of heat radiating light transmitting plates;
A wavelength conversion member comprising: a fluorescent layer containing a phosphor formed in a space closed by the pair of heat radiating light transmitting plates and the spacer.   The wavelength conversion member according to claim 1, wherein the spacer is integrated with at least one of the heat radiating light transmitting plates.   3. The wavelength conversion member according to claim 1, wherein one of the pair of heat-radiating light-transmitting plates is a long-wavelength transmission filter that reflects ultraviolet light and short-wavelength visible light and transmits longer-wavelength visible light.   The light-emitting device provided with the wavelength conversion member of Claim 1, 2, or 3, and an LED element. A substrate for supporting the wavelength conversion member;
The light-emitting device according to claim 4, wherein the spacer and the base are integrated.