JP3898721B2 - Light emitting device and lighting device - Google Patents

Description

  The present invention relates to a light-emitting device and a lighting device that radiate light emitted from a light-emitting element to the outside after wavelength conversion with a phosphor.

  A light-emitting device 11 for housing a light-emitting element 14 such as a conventional light-emitting diode (LED) is shown in FIG. As shown in FIG. 4, the light emitting device has a mounting portion 12a for mounting the light emitting element 14 at the center of the upper surface, and electrically connects the inside and outside of the light emitting device 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 for adhering and fixing to the upper surface of the base 12 and accommodating the light emitting element 14 in the center portion It is mainly composed of the formed frame body 13 made of metal, resin, ceramics or the like.

  The substrate 12 is made of an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, ceramics such as glass ceramics, or a resin such as an epoxy resin. When the substrate 12 is made of ceramics, the metallized wiring layer is formed on the upper surface by baking 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, when the base 12 is molded, a lead terminal made of copper (Cu), iron (Fe) -nickel (Ni) alloy or the like protrudes at one end into the base 12. To be fixed.

  The frame 13 is made of a metal such as aluminum (Al) or Fe-Ni-cobalt (Co) alloy, a ceramic such as an alumina sintered body, or a resin such as an epoxy resin. It is formed by molding or the like. Furthermore, a through hole is formed in the central portion of the frame 13 so as to spread outward as it goes upward. To improve the light reflectance of the inner peripheral surface of the through hole, Al or the like is provided on the inner peripheral surface. The metal is deposited by vapor deposition or plating. The frame 13 is bonded to the upper surface of the base 12 by a brazing material such as solder, silver brazing, or a resin adhesive.

  Then, a wiring conductor (not shown) formed on the surface of the substrate 12 and the electrode of the light emitting element 14 are electrically connected via a bonding wire (not shown), and then the phosphor is applied to the surface of the light emitting element 14. After the layer 17 is formed, the inside of the frame 13 is filled with a transparent resin 15 and thermally cured, whereby the light emitted from the light-emitting element 14 is converted by the phosphor layer 17 so that light having a desired wavelength spectrum can be extracted. Can be made with equipment. Further, the light emitting element 14 is selected to include an ultraviolet region having an emission wavelength of 300 to 400 nm, and the color tone is adjusted by adjusting the mixing ratio of phosphor particles of the three primary colors red, blue and green contained in the phosphor layer 17. Can be designed freely.

In general, the phosphor particles are powder, and it is difficult to form the phosphor layer 17 with the phosphor alone. Therefore, the phosphor particles are mixed in a transparent member such as a resin or glass to form the surface of the light emitting element 14. In general, the phosphor layer 17 is applied.
Japanese Patent No. 3052663

  However, in the case of the conventional light emitting device 11, the light emitted to the lower side of the phosphor layer 17 after wavelength conversion by the phosphor layer 17 or the lower side on the upper surface of the phosphor layer 17 after being emitted from the light emitting element The light reflected by the light is repeatedly reflected inside the frame 13 and attenuated, or is absorbed by the base 12 and the light emitting element 14, resulting in a problem that the light loss is remarkably increased.

  Further, the light emitted obliquely upward from the light emitting element 14 is radiated at a large radiation angle outside the light emitting device 11 without being reflected by the frame 13, so the radiation angle is increased and the axial luminous intensity is increased. It had the problem of being low.

  Therefore, the present invention has been completed in view of the above-described conventional problems, and an object thereof is to provide a light emitting device and an illuminating device that improve light extraction efficiency and have high radiated light intensity, high on-axis luminous intensity, and luminance. That is.

The light emitting device of the present invention includes a base, a light emitting element mounted on the base, a first light transmissive member covering the light emitting element, and the first light transmissive member above the first light transmissive member. A second translucent member disposed with a gap with respect to the one translucent member, a translucent material, and light emitted from the light-emitting element contained in the translucent material; A phosphor layer made of a phosphor to be converted and disposed in contact with the upper surface of the second translucent member.

The light-emitting device of the present invention includes a first light-transmitting member that covers the light-emitting element, a second light-transmitting member that is disposed with a gap with respect to the first light-transmitting member, and the second light-transmitting member. by comprises of a light-transmitting member phosphor layer disposed in contact with the upper surface of, to improve the light extraction efficiency, thereby improving the emission luminance.

  The light emitting device 1 of the present invention will be described in detail below. FIG. 1 and FIG. 5 are sectional views showing various examples of the embodiment of the light emitting device 1 of the present invention. In FIGS. 1 and 5, 2 is a base, 3 is a frame, 4 is a light emitting element, 5 is a first light transmissive member, 6 is a second light transmissive member, and 7 is a phosphor layer. Thus, the light emitting device 1 is configured.

  The substrate 2 in the present invention is made of alumina ceramic, aluminum nitride sintered body, mullite sintered body, ceramic such as glass ceramic, resin such as epoxy resin, or metal, and functions as a support member that supports the light emitting element 4. To do. Moreover, it has the mounting part 2a for mounting the light emitting element 4 on the upper surface.

  When the base 2 is ceramic, a wiring conductor (not shown) for electrically connecting the light emitting element 4 is formed on the mounting portion 2a and its periphery. The wiring conductor is led out to the outer surface of the base 2 and connected to the external electric circuit board, whereby the light emitting element 4 and the external electric circuit board are electrically connected.

  As a method of connecting the light emitting element 4 to the wiring conductor, a method of connecting via wire bonding (not shown) or a flip chip bonding method in which the lower surface of the light emitting element 4 is connected by solder bumps (not shown). The method used is used. Preferably, the connection is made by a flip chip bonding method. Thereby, since the wiring conductor can be provided directly under the light emitting element 4, it is not necessary to provide a space for providing the wiring conductor on the upper surface of the base 2 around the light emitting element 4. Therefore, it is possible to effectively suppress the light emitted from the light emitting element 4 from being absorbed in the space for the wiring conductor of the base body 2 to reduce the intensity of the emitted light, and to reduce the size of the light emitting device 1. .

  When the base 2 is made of ceramic, the wiring conductor is formed of a metallized layer of metal powder such as W, Mo, Cu, silver (Ag), for example. Alternatively, an input / output terminal made of an insulator on which a wiring conductor is formed is provided by being fitted into a through hole provided in the base 2. Moreover, when the base | substrate 2 consists of resin, it forms, for example by embedding lead terminals, such as a Fe-Ni-Co alloy.

  In addition, it is better to deposit a metal with excellent corrosion resistance, such as Ni or gold (Au), with a thickness of about 1 to 20 μm on the exposed surface of the wiring conductor, effectively preventing oxidative corrosion of the wiring conductor. In addition, the connection between the light emitting element 4 and the wiring conductor can be strengthened. Therefore, for example, an Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the exposed surface of the wiring conductor by an electrolytic plating method or an electroless plating method. Is more preferable.

  The frame 3 in the present invention 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 cutting, die molding, extrusion molding, or the like.

  Further, the surface of the inner peripheral surface of the frame 3 should have an arithmetic average roughness Ra of the surface of 0.1 μm or less, whereby the light of the light emitting element 4 is favorably reflected to the upper side of the light emitting device 1. be able to. When Ra exceeds 0.1 μm, it becomes difficult to reflect light upward on the inner peripheral surface of the frame 3 of the light-emitting element 4 and 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.

  In addition, the phosphor layer 7 in the present invention is mixed with, for example, phosphors of three primary colors of red, blue, and green in a translucent member such as an epoxy resin, a silicone resin, an acrylic resin, or glass. It forms by apply | coating or mounting on the upper surface of a 2nd translucent member. Various materials are used as phosphors. For example, red is La2O2S: Eu (Eu-doped La2O2S) phosphor, green is ZnS: Cu, Al phosphor, and blue is (BaMgAl) 10O12: Eu fluorescence. Particulate matter such as body is used. Furthermore, such a phosphor is not limited to one type, and a light having a desired emission spectrum and color can be output by blending a plurality of phosphors at an arbitrary ratio.

  The thickness of the phosphor layer 7 is preferably 0.1 to 1 mm. Thereby, the wavelength of the light emitted from the light emitting element 4 can be efficiently converted. When the thickness of the phosphor layer 7 is less than 0.1 mm, the ratio of the light emitted from the light emitting element 4 that is transmitted through the phosphor layer 7 without being wavelength-converted by the phosphor layer 7 is increased. Tends to decrease. On the other hand, if the thickness exceeds 1 mm, the light whose wavelength has been converted by the phosphor layer 7 is easily absorbed by the phosphor layer 7 and the intensity of radiated light tends to decrease.

  The first light transmissive member 5 of the present invention is formed so as to cover the light emitting element 4. The first 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 transmissivity with respect to light from the ultraviolet region to the visible light region. The conductive member 5 is made of transparent resin such as silicone resin, epoxy resin, urea resin, low melting point glass, sol-gel glass, or the like. 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 first light transmissive member 5.

  Preferably, the first translucent member is made of a silicone resin. Since the silicone resin does not easily deteriorate with respect to light such as ultraviolet light emitted from the light-emitting element 4, a light-emitting device with high sealing reliability can be provided.

  Moreover, as shown in FIG. 2, the 1st translucent member 5 is good to be hemispherical. Thereby, since the traveling direction of the light emitted from the light emitting element 4 can be orthogonal to the upper surface of the first light transmissive member 5, the light is emitted from the upper surface of the first light transmissive member 5. Light can be efficiently extracted without being totally reflected, and the light emitting device 1 having high radiation light intensity can be obtained.

  In the light emitting device 1 of the present invention, it is preferable that the second light transmissive member 6 is formed on the lower surface of the phosphor layer 7. Thereby, even if the phosphor is exposed on the lower surface of the phosphor layer 7, the emitted phosphor is covered with the second translucent member 6, so that the light emitted from the phosphor is second Light can be fully reflected on the lower surface of the translucent member 6 to allow light to travel upward. Therefore, it is possible to effectively prevent the light from being directly emitted from the phosphor into the gap and absorbed by the substrate 2 or the light emitting element 4, and the light emitting device 1 capable of further improving the light extraction efficiency. it can.

  Such a second translucent member 6 is provided so as to cover the first translucent member 5 with a gap between the second translucent member 5 and the ultraviolet light region to the visible light region. It is good to consist of a thing with the high transmittance | permeability with respect to the light of this. Thus, since the 2nd translucent member 6 is provided so that a clearance gap may be provided between the 1st translucent member and the 1st translucent member may be covered, the 1st translucent member is provided. The light emitted in a wide range from the upper surface of the conductive member 5 can be advanced in the upper direction perpendicular to the base 2 when entering the lower surface of the second light transmissive member 6. Therefore, the optical path length transmitted through the phosphor layer 7 can be approximated in the entire phosphor layer 7 to effectively prevent color unevenness due to the difference in wavelength conversion efficiency, and to the axis of the light emitting device 1. Light can be emitted with high directivity to increase the intensity of emitted light, the on-axis luminous intensity, and the luminance.

  Furthermore, since the lower surface of the second translucent member 6 is in contact with the air layer having a lower refractive index, light emitted from the phosphor in the phosphor layer 7 in the lower direction, or the upper surface of the phosphor layer 7 Most of the light reflected in the lower direction can be totally reflected by the lower surface of the second translucent member 6, and the light is repeatedly reflected inside the frame body 3 to be attenuated, or the base 2 and the light emission. It is possible to effectively prevent the element 4 from being absorbed, and to effectively suppress a decrease in light extraction efficiency.

  Note that the gap between the first translucent member 5 and the phosphor layer 7 or the gap between the first translucent member 5 and the second translucent member 6 is the first translucent member. It is only necessary that the refractive index of the light-transmitting member 5, the second light-transmitting member 6, and the light-transmitting member constituting the phosphor layer is smaller than that of the air layer. For example, it may be a layer of other gas or a layer of a light-transmissive member having a low refractive index.

  The second light transmissive member 6 is preferably made of a material having a small refractive index difference from the light transmissive member constituting the phosphor layer 7 and having a high transmittance with respect to light from the ultraviolet region to the visible light region. For example, the 2nd translucent member 5 consists of transparent resins, such as a silicone resin, an epoxy resin, and a urea resin, low melting glass, sol-gel glass, etc. Preferably, the same material as the translucent member constituting the phosphor layer 7 may be used. Thereby, light can be transmitted through the interface between the phosphor layer 7 and the second translucent member to reduce light loss, and the phosphor layer 7 and the second translucent member 5 can be reduced. These can be effectively prevented from being peeled off by stress due to a difference in thermal expansion coefficient.

  Preferably, the second light transmissive member 5 is made of silicone resin. Since the silicone resin does not easily deteriorate with respect to light such as ultraviolet light emitted from the light-emitting element 4, a light-emitting device with high sealing reliability can be provided.

  Further, the thickness of the first translucent member 5, the distance (gap width) between the first translucent member 5 and the phosphor layer 7, the first translucent member 5 and the second translucent light. The distance (gap width) from the light transmitting member 6 and the thickness of the second light transmitting member 6 are the same as the interface between the first light transmitting member 5 and the phosphor layer 7 and the first light transmitting member 5 and the first light transmitting member 5. The reflection efficiency at the interface between the two translucent members 6 may be selected appropriately.

  Preferably, as shown in FIG. 5, the distance (gap width) between the upper surface of the first light-transmissive member 5 and the phosphor layer 7, or the upper surface of the first light-transmissive member 5 and the second light-transmissive member. It is preferable that the distance (gap width) with respect to the light transmissive member 6 is smaller than the thickness of the first light transmissive member 5. As a result, the thermal expansion of the light-emitting element 4 is changed by reducing the thermal expansion of the gap and sufficiently absorbing the stress due to the thermal expansion of the gap by the first translucent member 5 to generate stress in the light-emitting element 4. It can prevent well.

  On the other hand, from the viewpoint of reducing light loss, the total thickness of the first light transmissive member 5 and the second light transmissive member 6 (if there is no second light transmissive member 6, the first The thickness of the translucent member 5 is the width of the gap (the distance between the first translucent member 5 and the second translucent member 6 or the first translucent member 5 and the phosphor layer 7. It is better that it is smaller than the interval. Thereby, in the path through which the light emitted from the light emitting element 4 passes until it is emitted to the outside, the ratio of the gap with a small refractive index can be increased, and it is confined in the light emitting device or repeatedly diffusely reflected. In addition, as shown in FIG. 3, glass, sapphire, quartz, or a resin (plastic) such as epoxy resin, silicone resin, acrylic resin, etc. on the upper surface of the frame 3 The lid body 8 made of the transparent member may be placed and fixed. In this case, while protecting the light emitting element 4, the wiring conductor, the bonding wire, the first light transmissive member 5, and the second light transmissive member 6 installed inside the frame 3, the inside of the light emitting device 1 is protected. The light emitting element 4 can be hermetically sealed, and the light emitting element 4 can be operated stably for a long time. Further, by forming the lid 8 in the shape of a lens and adding the function of an optical lens, it is possible to collect or disperse the light and extract the light outside the light emitting device 1 with a desired radiation angle and intensity distribution. .

  In addition, the light emitting device 1 of the present invention is a single light source set in a predetermined arrangement and used as a light source, or a plurality of light emitting devices, for example, a lattice shape, a staggered shape, a radial shape, or a plurality of light emission types. A lighting device according to the present invention can be obtained by installing a light emitting device group of a circular shape or a polygonal shape, which is composed of a plurality of devices, so as to have a predetermined arrangement, such as a concentric group of light emitting device groups. . Thereby, the light extraction efficiency can be improved, and an illuminating device with high radiated light intensity, high on-axis luminous intensity, and luminance can be provided.

  In addition, since light emission by electron recombination of the light emitting element 4 made of a semiconductor is used, it is possible to achieve lower power consumption and longer life than a conventional lighting device using discharge, and a small size that generates less heat. It can be set as the illuminating device. As a result, fluctuations in the center wavelength of the light generated from the light emitting element 4 can be suppressed, and light can be emitted with a stable radiant light intensity and radiant light angle (light distribution distribution) over a long period of time. It can be set as the illuminating device by which the color nonuniformity in the surface and the bias of illuminance distribution were suppressed.

  In addition, the light emitting device 1 of the present invention is installed in a predetermined arrangement as a light source, and a reflection jig, an optical lens, a light diffusing plate, or the like optically designed in an arbitrary shape is installed around the light emitting device 1 It can be set as the illuminating device which can radiate | emit light of arbitrary light distribution.

  For example, a plurality of light emitting devices 1 are arranged in a plurality of rows on the light emitting device driving circuit board 10 as shown in the plan view and the cross-sectional view shown in FIGS. 6 and 7, and are optically designed in an arbitrary shape around the light emitting device 1. In the case of an illuminating device in which the reflecting jig 9 is installed, in a plurality of light emitting devices 1 arranged on one adjacent row, an arrangement in which the interval between the adjacent light emitting devices 1 is not the shortest, so-called zigzag shape It is preferable that That is, when the light-emitting devices 1 are arranged in a grid, the light-emitting devices 1 serving as light sources are arranged on a straight line, so that glare is strong, and such a lighting device enters human vision. Thus, discomfort and eye damage are likely to occur, but by forming a staggered pattern, glare is suppressed and discomfort and damage to the eyes of the human eye can be reduced. Furthermore, since the distance between the adjacent light emitting devices 1 is increased, thermal interference between the adjacent light emitting devices 1 is effectively suppressed, and heat in the light emitting device driving circuit board 10 on which the light emitting device 1 is mounted is reduced. Clouding is suppressed and heat is efficiently dissipated outside the light emitting device 1. As a result, it is possible to manufacture a long-life lighting device with stable optical characteristics over a long period of time with little obstacles to human eyes.

  In addition, the lighting device is a concentric arrangement of a circular or polygonal light-emitting device group consisting of a plurality of light-emitting devices 1 on the light-emitting device drive circuit board 10 as shown in the plan view and the sectional view shown in FIGS. In the case of the illuminating device formed in a plurality of groups, it is preferable to increase the number of the light emitting devices 1 arranged in one circular or polygonal light emitting device 1 group toward the outer peripheral side from the center side of the illuminating device. Thereby, more light-emitting devices 1 can be arranged while keeping the interval between the light-emitting devices 1 moderately, and the illuminance of the illumination device can be further improved. Moreover, the density of the light-emitting device 1 in the central part of the lighting device can be lowered to suppress heat accumulation in the central part of the light-emitting device drive circuit board 10. Therefore, the temperature distribution in the light emitting device driving circuit board 10 becomes uniform, heat is efficiently transmitted to the external electric circuit board and the heat sink on which the lighting device is installed, and the temperature rise of the light emitting device 1 can be suppressed. As a result, the light emitting device 1 can operate stably over a long period of time, and a long-life lighting device can be manufactured.

  Examples of such lighting devices include general lighting fixtures, chandelier lighting fixtures, residential lighting fixtures, office lighting fixtures, store lighting, display lighting fixtures, street lighting fixtures, used indoors and outdoors. Guide light fixtures and signaling devices, stage and studio lighting fixtures, advertising lights, lighting poles, underwater lighting lights, strobe lights, spotlights, security lights embedded in power poles, emergency lighting fixtures, flashlights, Examples include electronic bulletin boards and the like, backlights for dimmers, automatic flashers, displays and the like, moving image devices, ornaments, illuminated switches, optical sensors, medical lights, in-vehicle lights, and the like.

  It should be noted that the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the present invention.

  Further, the lighting device of the present invention is not limited to one in which a plurality of light emitting devices 1 are installed in a predetermined arrangement, but may be one in which one light emitting device 1 is installed in a predetermined arrangement.

  Examples of the light emitting device 1 of the present invention will be described below.

  First, an alumina ceramic substrate to be the base 2 was prepared. The base 2 was a rectangular parallelepiped having a width of 8 mm, a depth of 8 mm, and a thickness of 0.5 mm.

  Further, a wiring conductor was formed from the mounting portion 2 a on which the light emitting element 4 of the base 2 is mounted to the outer surface of the base 2. The wiring conductor of the mounting portion 2a was formed into a circular pad having a diameter of 0.1 mm by a metallized layer made of Mo—Mn powder, and a Ni plating layer having a thickness of 3 μm was deposited on the surface thereof. Moreover, the wiring conductor inside the base body 2 was formed by an electrical connection portion made of a through conductor, a so-called through hole. This through hole was also formed of a metallized conductor made of Mo-Mn powder, like the wiring conductor of the mounting portion 2a.

  Further, the base 2 and the frame 3 are bonded with an adhesive, and then the first light-transmissive member 5 made of an epoxy resin having a refractive index of 1.76 is disposed inside the frame 3 so as to cover the light emitting element 4. Is placed in a hemispherical shape with a radius of 0.4 mm, and a gap of 1.1 mm is provided in the height direction from the hemispherical zenith, and the thickness is made of a silicone resin with a refractive index of 1.41 above it. A plate-shaped second light-transmissive member 6 having a thickness of 0.1 mm was adhered to the inside of the frame 3 so as to cover the first light-transmissive member 5. Then, on the upper surface of the second translucent member 6, a phosphor made of La2O2S: Eu for red, ZnS: Cu, Al for green, and (BaMgAl) 10O12: Eu for blue is used as a translucent member made of silicone resin. The light emitting device 1 of the present invention was configured by covering the phosphor layer 7 contained.

  On the other hand, as a comparative example, the same structure as the light emitting device 1 of the present invention was configured except that the frame 3 was filled with the first translucent member 5 with a thickness of 1.5 mm. .

  When the total luminous flux was measured for the light emitting device 1 of the present invention thus manufactured and the comparative example, the total luminous flux of the light emitting device 1 of the present invention was increased by about 10% with respect to the comparative example. It has been found that the light emitting device 1 of the invention is superior.

  It should be noted that the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the present invention.

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 other example of embodiment of the light-emitting device of this invention. It is sectional drawing of the conventional light-emitting device. It is sectional drawing which shows the other example of embodiment of the light-emitting device of this invention. It is a top view which shows an example of embodiment of the illuminating device of this invention. It is sectional drawing of the illuminating device of FIG. It is a top view which shows the other example of embodiment of the illuminating device of this invention. It is sectional drawing of the illuminating device of FIG.

Explanation of symbols

1: Light-emitting device 2: Base 2a: Mounting portion 3: Frame body 4: Light-emitting element 5: First light-transmitting member 6: Second light-transmitting member 7: Phosphor layer 8: Lid

Claims (8)

A substrate;
A light emitting device mounted on the substrate;
A first light transmissive member covering the light emitting element;
A second translucent member disposed above the first translucent member with a gap with respect to the first translucent member;
Becomes the light emitted from the light emitting element are contained in the transparent material and the light-transmitting material and a fluorescent material for wavelength-converting, disposed in contact with an upper surface of the second translucent member fluorescence A light emitting device comprising a body layer.   The light emitting device according to claim 1, wherein the second translucent member is made of a silicone resin.   The light-emitting device according to claim 1, wherein the phosphor emits red light, green light, and blue light.   The light-emitting device according to claim 1, wherein the translucent material of the phosphor layer is a silicone resin.   The light emitting device according to claim 1, wherein the first light transmissive member is made of a silicone resin that transmits ultraviolet light and visible light.   The light emitting device according to claim 1, wherein the first translucent member is hemispherical.   The light emitting device according to claim 1, wherein the light emitting element is a light emitting diode.   8. A lighting device, wherein the light emitting device according to claim 1 is used as a light source.

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