JP2013089433A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device capable of reducing the difference of gradation in an irradiated region.SOLUTION: The lighting device 1 is provided with a first substrate 2 of a long shape, a second substrate 3 of a long shape which is installed adjacent to a side in a longitudinal direction of the first substrate 2 along the longitudinal direction of the first substrate 2, a plurality of semiconductor light-emitting elements 4 which are installed along the longitudinal direction of the both substrates on the first substrate 2 and the second substrate 3, and a translucent cover 5 of a long shape which is installed along the longitudinal direction of the first substrate 2 and the second substrate 3 so as to cover the plurality of semiconductor light-emitting elements 4. Further, the translucent cover 5 is formed to have a transmittance larger in the periphery part 5b located in the periphery region of the center part 5f1 of the translucent cover 5 than in the center part 5f1 in the cross-section orthogonal to the longitudinal direction.

Description

  The present invention relates to a lighting device including a semiconductor light emitting device.

  In recent years, development of a semiconductor light emitting device and a lighting device using a semiconductor light emitting element such as a light emitting diode (LED) as a light source has been advanced (for example, see Patent Document 1). An illuminating device having a semiconductor light emitting device is excellent in directivity and has a feature that the luminance of the front surface of the semiconductor light emitting device is increased. For this reason, an illumination device in which a plurality of semiconductor light emitting devices are mounted on a flat plate has a region with a large amount of light emitted from the semiconductor light emitting device and a region with a small amount of irradiated light, particularly in a dark place. Differences in gradation are likely to occur due to the occurrence of light and dark.

Japanese Patent Laid-Open No. 7-77942

  An object of this invention is to provide the illuminating device which can reduce the difference in gradation in the irradiated area | region.

  An illumination device according to an embodiment of the present invention includes a long first substrate, a long second substrate provided adjacent to a longitudinal side of the first substrate, and the first substrate. A plurality of light emitting elements provided on the one substrate and the second substrate along the longitudinal direction of both substrates, and on the first substrate and the second substrate so as to cover the plurality of light emitting elements. A translucent cover having a long shape provided along the longitudinal direction, and the translucent cover has a transmissivity of a peripheral portion located in a peripheral region of a central portion in a cross section orthogonal to the longitudinal direction. It is larger than the transmittance of the central portion.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device which can reduce the difference of a gradation in the irradiated area | region can be provided.

It is the general-view perspective view which looked at the illuminating device which concerns on one Embodiment of this invention from diagonally upward to diagonally downward. FIG. 2 is an overview perspective view showing a state where a translucent cover is removed from the lighting device of FIG. 1. FIG. 2 is an overview perspective view of the housing of FIG. 1 as viewed from obliquely upward to obliquely downward. 1 shows a lighting device according to an embodiment of the present invention, and is a cross-sectional view taken along X1-X1 'of FIG. It is a general | schematic perspective view of the illuminating device which decomposed | disassembled a part of illuminating device. It is the general | schematic perspective view which looked at the semiconductor light-emitting element provided on the board | substrate from diagonally upward to diagonally downward. It is the general-view perspective view which looked at a part of reflector from diagonally upward to diagonally downward. It is the general | schematic perspective view which looked at the semiconductor light-emitting device of the illuminating device which concerns on one Embodiment of this invention from diagonally upward to diagonally downward, Comprising: The inside of a semiconductor light-emitting device is shown. FIG. 9 is a cross-sectional view of the semiconductor light emitting device shown in FIG. 8 along X2-X2 ′.

  Embodiments of a lighting device according to the present invention will be described below with reference to the accompanying drawings. In addition, this invention is not limited to the following embodiment.

<Configuration of lighting device>
The lighting device 1 is directly attached to a room such as a ceiling or a wall, or is used outdoors. And the light emitted from the illuminating device 1 can illuminate indoors or outdoors.

  The illuminating device 1 includes a long first substrate 2 and a long first substrate 2 that is provided along the longitudinal side of the first substrate 2 and adjacent to the longitudinal side of the first substrate 2. Two substrates 3, a plurality of light emitting elements 4 provided on the first substrate 2 and the second substrate 3 along the longitudinal direction of both substrates, and the first substrate 2 so as to cover the plurality of light emitting elements 4. And the elongate translucent cover 5 provided along the longitudinal direction on the 2nd board | substrate 3 is provided. Further, the translucent cover 5 has a cross section orthogonal to the longitudinal direction such that the transmittance of the peripheral portion 5f2 located in the peripheral region of the central portion 5f1 of the translucent cover 5 is larger than the transmittance of the central portion 5f1. Is formed.

  The first substrate 2 and the second substrate 3 are mounted in the housing 6. Then, the housing 6 is connected to the outside. The casing 6 is a long base body, and a partition wall 6a is formed therein so that an internal space in which the first substrate 2 is provided and an internal space in which the second substrate 3 is provided are separated. And the housing | casing 6 can provide a some member in each internal space, and the opening edge which the upper part opened on each internal space is formed. Alternatively, the housing 6 may be formed such that the internal space in which the first substrate 2 and the second substrate 3 are provided is a single space. And the housing | casing 6 can provide the 1st board | substrate 2, the 2nd board | substrate 3, and a some member in the bottom part of internal space. The housing 6 is made of, for example, a metal such as aluminum, copper, or stainless steel, or plastic or resin.

  The casing 6 has a length in the longitudinal direction set to, for example, 200 mm to 2000 mm in plan view, and a length in the short direction set to, for example, 15 mm to 50 mm. Further, the casing 6 is set to have a vertical length of, for example, 5 mm or more and 50 mm or less. The thermal conductivity of the housing 6 is set to, for example, 10 W / (m · K) or more and 500 W / (m · K) or less.

  The first substrate 2 is provided in the housing 6. The 1st board | substrate 2 is elongate, Comprising: The several semiconductor light-emitting device 4 is mounted on the main surface. Note that the length of the first substrate 2 in the longitudinal direction in a plan view is set to, for example, 190 mm or more and 1990 mm or less, and the length in the lateral direction is set to, for example, 5 mm or more and 20 mm or less. The length of the first substrate 2 in the vertical direction is set to, for example, 0.5 mm or more and 2 mm or less.

  As the first substrate 2, for example, a printed wiring board made of resin, a resin board such as a flexible wiring board, a metal plate such as a glass board or an aluminum board, or the like can be used. The first substrate 2 can be fixed to the housing 6 via a screw or a bonding material. The second substrate 3 has the same configuration as the first substrate 2.

  The light emitting element 4 is mounted on the first substrate 2 and the second substrate 3. The plurality of light emitting elements 4 are provided along the longitudinal direction of the first substrate 2 and the second substrate 3.

  Each of the light emitting elements 4 includes a chip mounting substrate 41, a light emitting chip 42 provided on the chip mounting substrate 41, a frame body 43 surrounding the light emitting chip 42, and a sealing provided in a region surrounded by the frame body 43. A member 44 and a wavelength conversion member 46 supported by the frame body 43 and connected to the frame body 43 via an adhesive member 45 are provided.

  The light emitting chip 42 is, for example, a light emitting diode, and light is emitted by recombination of electrons and holes in a pn junction in the light emitting chip 42. The chip mounting substrate 41 is provided on the first substrate 2 and the second substrate 3. The chip mounting substrate 41 is joined on the first substrate 2 and the second substrate 3 so as to be electrically connected to each other through, for example, solder or a conductive adhesive. The chip mounting substrate 41 can be made of, for example, a ceramic material such as alumina, mullite, or glass ceramics, or a composite material obtained by mixing a plurality of these materials. The chip mounting substrate 41 may be made of a polymer resin in which metal oxide fine particles are dispersed.

  When the surface of the chip mounting substrate 41 is a diffusing surface, the light emitted from the light emitting chip 42 is applied to the surface of the chip mounting substrate 41 and diffusely reflected. The light emitted from the light emitting chip 42 can be radiated in multiple directions by diffuse reflection, and the light emitted from the light emitting chip 42 can be prevented from being concentrated at a specific location in the housing 6.

  Here, the chip mounting substrate 41 is provided with a wiring conductor, and is electrically connected to the first substrate 2 via the wiring conductor. The wiring conductor is made of a conductive material such as tungsten, molybdenum, manganese, or copper. The wiring conductor is formed by printing a metal paste obtained by adding an organic solvent to a powder such as tungsten on the chip mounting substrate 41 in a predetermined pattern.

  The light emitting chip 42 is mounted on the chip mounting substrate 41. The light emitting chip 42 is electrically connected to a wiring conductor formed on the chip mounting substrate 41 via an adhesive material such as solder or a conductive adhesive, or a bonding wire.

  The light emitting chip 42 is formed on a substrate such as sapphire, gallium nitride, aluminum nitride, zinc oxide, silicon carbide, silicon or zirconium diboride by chemical vapor deposition such as metal organic chemical vapor deposition or molecular beam epitaxial growth. And produced by growing a semiconductor layer. The thickness of the light emitting chip 42 is, for example, 30 μm or more and 1000 μm or less.

The light emitting chip 42 includes a first semiconductor layer, a light emitting layer formed on the first semiconductor layer, and a second semiconductor layer formed on the light emitting layer. The first semiconductor layer, the light emitting layer, and the second semiconductor layer are, for example, a group III nitride semiconductor, a group III-V semiconductor such as gallium phosphide or gallium arsenide, or a group III nitride such as gallium nitride, aluminum nitride, or indium nitride. A semiconductor or the like can be used. The thickness of the first semiconductor layer is, for example, 1 μm or more and 5 μm or less. The thickness of the light emitting layer is, for example, 25 nm or more and 150 nm or less. The thickness of the second semiconductor layer is, for example, not less than 50 nm and not more than 600 nm. In addition, the light emitting chip 42 configured as described above can emit excitation light having a wavelength range of, for example, 370 nm to 420 nm.

A frame-like frame body 43 is provided on the chip mounting substrate 41 so as to surround the light emitting element 42 with a space from the light emitting element 42. The frame body 43 is connected to the chip mounting substrate 41 via, for example, solder or an adhesive. The frame 43 is a ceramic material and is made of a porous material such as aluminum oxide, titanium oxide, zirconium oxide, or yttrium oxide. The frame body 43 is made of a porous material, whereby many fine holes are formed on the surface of the frame body 43.

  Further, the frame body 43 is formed so that the inclined inner wall surface expands outward as it goes from the lower end to the upper end. The inner wall surface of the frame 43 functions as a reflection surface for excitation light emitted from the light emitting element 42. When the inner wall surface of the frame body 43 is a diffusion surface, the light emitted from the light emitting element 42 is diffusely reflected on the inner wall surface of the frame body 43. The light emitted from the light emitting element 42 can travel upward without being concentrated at a specific location.

  The inclined inner wall surface of the frame body 43 may be formed with a metal layer made of, for example, tungsten, molybdenum, copper, or silver, and a plated metal layer made of nickel, gold, or the like that covers the metal layer. The plated metal layer has a function of reflecting light emitted from the light emitting element 42. The inclination angle of the inner wall surface of the frame body 43 is set to an angle of 55 ° to 70 ° with respect to the upper surface of the chip mounting substrate 41, for example.

  A region surrounded by the frame body 43 is filled with a sealing member 44. The sealing member 44 has a function of sealing the light emitting element 42 and transmitting light emitted from the light emitting element 42. The sealing member 44 is a region surrounded by the frame body 43 in a state in which the light emitting element 42 is accommodated inside the frame body 43, and is a translucent insulating resin such as a silicone resin, an acrylic resin, or an epoxy resin. Alternatively, a light-transmitting insulating glass can be used.

  The wavelength conversion member 46 is supported by the frame body 43 and provided to face the light emitting element 42 with a space therebetween. The wavelength conversion member 46 is provided on the frame body 43 through a sealing member 44 that seals the light emitting element 42 and a gap.

  The wavelength conversion member 46 is joined to the frame body 43 via the adhesive member 45. The adhesive member 45 is attached from the end portion of the lower surface of the wavelength conversion member 46 to the side surface of the wavelength conversion member 46 and further to the end portion of the upper surface of the wavelength conversion member 46.

  For the adhesive member 45, for example, a thermosetting resin such as a polyimide resin, an acrylic resin, an epoxy resin, a urethane resin, a cyanate resin, a silicone resin, or a bismaleimide triazine resin can be used. The adhesive member 45 may be made of a thermoplastic resin such as a polyether ketone resin, a polyethylene terephthalate resin, or a polyphenylene ether resin.

  As the material of the adhesive member 45, a material having a thermal expansion coefficient between the thermal expansion coefficient of the frame body 43 and the thermal expansion coefficient of the wavelength conversion member 46 may be selected. By selecting such a material as the material of the adhesive member 45, when the frame body 43 and the wavelength conversion member 46 are thermally expanded, they are about to peel off due to the difference in the coefficient of thermal expansion between them. Can be suppressed, and both can be connected well.

  Since the adhesive member 45 is attached to the end of the lower surface of the wavelength conversion member 46, the area to which the adhesive member 45 is attached is increased, and the frame body 43 and the wavelength conversion member 46 are firmly connected. be able to. As a result, the connection strength between the frame body 43 and the wavelength conversion member 46 can be improved, and bending of the wavelength conversion member 46 is suppressed. And it can suppress effectively that the optical distance between the light emitting element 42 and the wavelength conversion member 46 fluctuates.

The wavelength conversion member 46 emits light when excitation light emitted from the light emitting element 42 enters the inside and the phosphor contained therein is excited. Here, the wavelength conversion member 46 is made of, for example, a translucent resin such as silicone resin, acrylic resin, or epoxy resin, or translucent glass. In the translucent resin or translucent glass, for example, 430 nm or more. 4
Contains blue phosphors that emit fluorescence of 90 nm or less, such as green phosphors that emit fluorescence of 500 nm to 560 nm, such as yellow phosphors that emit fluorescence of 540 nm to 600 nm, such as red phosphors that emit fluorescence of 590 nm to 700 nm Has been. The phosphor is contained so as to be uniformly dispersed in the wavelength conversion member 46. In addition, the thickness of the wavelength conversion member 46 is set to 0.3 mm or more and 3 mm or less, for example.

  Further, the thickness of the end portion of the wavelength conversion member 46 is set to be constant. The thickness of the wavelength conversion member 46 is set to, for example, 0.3 mm or more and 3 mm or less. Here, the constant thickness includes a thickness error of the wavelength conversion member 46 of 0.1 mm or less. By making the thickness of the wavelength conversion member 46 constant, the amount of light excited by the wavelength conversion member 46 can be adjusted to be uniform, and uneven brightness in the wavelength conversion member 46 can be suppressed. it can.

  Next, the reflector 7 provided on the semiconductor light emitting element 4 will be described. In the reflector 7, the claw portion 7 a, which is a part of the reflector 7, is hooked on a part of the housing 6 that protrudes from the inner wall surface of the housing 6, so that the reflector 7 is on the first substrate 2 and the second substrate 3. It is provided so that it may be located in each. In addition, when the reflector 7 is positioned on the first substrate 2 or the second substrate 3, a plurality of light guide holes 7h surrounding each of the plurality of semiconductor light emitting elements 4 in a plan view are formed. The reflector 7 reflects light emitted from the semiconductor light emitting element 4 and is made of a metal material such as aluminum, copper or stainless steel, or a ceramic material such as aluminum oxide, titanium oxide, zirconium oxide or yttrium oxide. Has been. In addition, the reflector 7 may be comprised by vapor-depositing aluminum on the inner wall surface of the reflector 7 which consists of polycarbonate resin shape | molded with the metal mold | die.

  The reflector 7 has a long outer shape when viewed in plan, and is provided with a plurality of light guide holes 7h penetrating in the vertical direction along the longitudinal direction. In the reflector 7, each of the plurality of light guide holes 7 h is arranged corresponding to each of the plurality of semiconductor light emitting elements 4. The light emitted from each semiconductor light emitting element 4 is extracted to the outside through the translucent cover 5 through the light guide hole 7h of the reflector located above the semiconductor light emitting element 4.

  The reflector 7 is inclined so that the inner peripheral surface of the light guide hole 7 h surrounding the semiconductor light emitting element 4 reflects light emitted from the semiconductor light emitting element 4 from below to above. The inner peripheral surface is formed to be inclined with respect to the upper surface of the first substrate 2 or the second substrate 3 at an angle of, for example, 30 ° to 80 °. In addition, the reflector 7 is set so that the vertical length of the reflector 7 is, for example, 5 mm or more and 50 mm or less. The diameter of the inner peripheral surface of the reflector 7 is set to 3 mm or more and 30 mm or less, for example. The thermal conductivity of the reflector 7 is set to, for example, 10 W / (m · K) or more and 500 W / (m · K) or less.

  The inner peripheral surface of the light guide hole 7h of the reflector 7 is formed so as to expand from the semiconductor light emitting element 4 toward the exit of the light guide hole 7h. Since the region surrounded by the inner peripheral surface of the light guide hole 7h becomes larger toward the exit of the light guide hole 7h, the light emitted from the semiconductor light emitting element 4 can be made difficult to be blocked by the reflector 7, and the semiconductor light emitting element 4 The irradiation area of the light emitted from can be increased. Thereby, the light emitted from the semiconductor light emitting element 4 located below the light guide hole 7h can be reflected by the inner peripheral surface of the light guide hole 7h and spread upward to be taken out with good directivity.

A light transmissive plate 8 is provided at the opening edge of the housing 6. The plate 8 covers the inside of the housing 6 and protects the semiconductor light emitting element 4. The plate body 8 can be fitted to the housing 6 by sliding in the plane direction. The semiconductor light emitting element 4 can be protected from the outside by the housing 6 and the plate body 8. The plate body 8 may be provided so as to be positioned on each of the first substrate 2 and the second substrate 3 in plan view, and integrally covers the first substrate 2 and the second substrate 3 in plan view. It is provided as follows.

  The plate 8 is made of a material that transmits light emitted from the semiconductor light emitting element 4 and is made of a light transmissive material such as resin or glass. Then, the light emitted from the semiconductor light emitting element 4 passes through the plate body 8 and is extracted outside. The plate body 8 is a rectangular plate body, and is provided so as to be positioned on each of the first substrate 2 and the second substrate 3 in plan view. The length is, for example, 20 mm or more and 2000 mm or less, and the length in the short direction in a plan view is set to, for example, 6 mm or more and 23 mm or less. Further, when the plate body 8 is provided so as to cover the first substrate 2 and the second substrate 3 integrally in plan view, the length in the longitudinal direction in plan view is, for example, It is 20 mm or more and 2000 mm or less, and the length in the lateral direction in a plan view is set to, for example, 13 mm or more and 48 mm or less. In addition, the plate body 8 is set to have a vertical length of, for example, 0.5 mm or more and 3 mm or less when viewed in a longitudinal section.

  In the lower part of the housing 6, a wiring groove L is provided for providing the electrical wiring 9 electrically connected to each of the first substrate 2 and the second substrate 3. Since the electrical wiring 9 is provided in the wiring groove L, the semiconductor light emitting element 4 and the electrical wiring 9 are arranged on different surfaces with the bottom surface of the housing 6 in between. As a result, the semiconductor light emitting element 4 does not block the emitted light by the electrical wiring 9 or apply a physical force from the electrical wiring 9, and can operate the lighting device 1 normally. it can. Furthermore, since the heat generated by the semiconductor light emitting element 4 is not directly transmitted to the electric wiring 5, member deterioration of the electric wiring 9 can be effectively suppressed.

  Next, the translucent cover 5 will be described. The translucent cover 5 is provided along the longitudinal direction of the first substrate 2 and the second substrate 3 so as to cover the plurality of semiconductor light emitting elements 4 on the housing 6. The translucent cover 5 is made of a material through which light emitted from the semiconductor light emitting element 4 is transmitted. For example, the translucent cover 5 is made of a light transmissive material such as resin or glass. Then, light emitted from the semiconductor light emitting element 4 passes through the translucent cover 5 and is extracted outside.

  The translucent cover 5 has a long shape in plan view, and a cross section perpendicular to the longitudinal direction is formed so as to be convexly curved upward. Since the translucent cover 5 is formed so as to be convexly convex upward, light extracted outside from the inside of the housing 6 can be spread and advanced so as to radiate. The translucent cover 5 has a length in the longitudinal direction when viewed in plan, for example, set to 200 mm or more and 2000 mm or less, and a length in the lateral direction, for example, set to 15 mm or more and 50 mm or less. . Further, when the translucent cover 5 is viewed in a longitudinal section, the length in the vertical direction in the region surrounded by the translucent cover 5 is set to, for example, 10 mm or more and 100 mm or less. The thickness of the translucent cover 5 is set to 0.5 mm or more and 2 mm or less, for example.

  As shown in FIG. 4, when the lighting device 1 is viewed in a vertical cross section, the light emitted from the pair of semiconductor light emitting elements 4 travels upward through the respective plate bodies 8. The light traveling upward from each plate body 8 tends to concentrate on the central portion 5 f 1 of the translucent cover 5. When a plurality of semiconductor light emitting elements 4 are arranged on a line on the first substrate 2 and the second substrate 3, the light from the plurality of semiconductor light emitting elements 4 overlaps and concentrates in the central portion 5 f 1 of the translucent cover 5. To do. Further, the semiconductor light emitting element 4 is excellent in directivity, and the upper luminance as the front surface of the semiconductor light emitting element 4 is increased. Therefore, the illumination device in which a plurality of semiconductor light emitting elements 4 are mounted on a flat plate has a region irradiated with light reflected from the inner peripheral surface of the light guide hole 7h of the reflector 7 from the semiconductor light emitting elements 4 in a dark place. A gradation difference is likely to appear between the region where the semiconductor light emitting elements 4 are gathered and the surrounding region.

  The translucent cover 5 is a part of the housing 6 that shields the internal space in which the first substrate 2 is provided and the internal space in which the second substrate 3 is provided at a position overlapping the central portion 5f1 of the translucent cover 5 in plan view. The partition wall 6a which is a part is located, and the plurality of semiconductor light emitting elements 4 are not arranged. By not disposing the semiconductor light emitting element 4 in the region overlapping the central portion 5f1 of the translucent cover 5, the difference in gradation can be suppressed by suppressing the amount of light extracted outside from the location where light tends to gather.

In the translucent cover 5, the peripheral portion 5f2 located in the peripheral region of the central portion 5f1 of the translucent cover 5 is set to have a larger transmittance than the central portion 5f1. The central portion 5f1 refers to a range from 5 mm to 50 mm from the center of the translucent cover 5 in plan view. The peripheral part 5f2 is an area excluding the central part 5f1. The transmittance of the central portion 5f1 is set to, for example, 50% or more and 90% or less. The transmittance of the peripheral portion 5f2 is set to 90% or more and 99% or less, for example. The transmittance can be measured by calculating the ratio of the total transmitted light flux to the parallel incident light flux of the test piece made of the transparent cover 5 using the method of JIS K7361-1 translated from ISO13468-1.

  The translucent cover 5 makes the peripheral part 5f2 from the central part 5f1 out of the central part 5f1 by making the transmissivity of the peripheral part 5f2 larger than the transmissivity of the central part 5f1. Can easily emit light to the outside. As a result, in the area illuminated by the light emitted from the illumination device 1, the gradation difference between the central part of the irradiation area and the peripheral part of the irradiation area can be reduced, and unevenness in illuminance can be suppressed. In addition, it is possible to create a light environment with excellent visibility.

  The translucent cover 5 is connected to the upper part of the housing 6 via a bonding material 10. The bonding material 10 is made of a material such as an epoxy resin, an acrylic resin, or a silicone resin, for example. The bonding material 10 can reduce the amount of heat transferred from the housing 6 through the bonding material 10 to the translucent cover 5 by selecting a material having a lower thermal conductivity than the translucent cover 5. It is possible to suppress the optical cover 5 from being thermally deformed, and it is possible to suppress a decrease in the transmittance of the translucent cover 5 due to heat. As a result, it is possible to make it difficult to shift the location of the translucent cover 5 with respect to the semiconductor light emitting element 4, to radiate light from the translucent cover 5 in a desired external direction, and to illuminate for a long period of time. 1 can be operated normally.

  Here, the method of making the transmittance of the central portion 5f1 smaller than the transmittance of the peripheral portion 5f2 can be realized by making the refractive index of the central portion 5f1 larger than the refractive index of the peripheral portion 5f2. By using, for example, an epoxy resin as the material constituting the central portion 5f1 and using, for example, a silicone resin as the material constituting the peripheral portion 5f2, the refractive index of the central portion 5f1 is 1.51, and the refractive index of the peripheral portion 5f2 is 1. 41. The refractive index of the central portion 5f1 is set to 1.45 or more and 1.55 or less, for example. The refractive index of the peripheral portion 5f2 is set to 1.4 or more and 1.5 or less, for example. Here, by making the refractive index of the central portion 5f1 larger than the refractive index of the peripheral portion 5f2, the light extracted outward from the inside of the housing 6 travels from the central portion 5f1 toward the peripheral portion 5f2. It can be made easy. As a result, when viewed in plan, the transmittance of the central portion 5f1 can be made smaller than the transmittance of the peripheral portion 5f2.

Further, as a method of making the transmittance of the central portion 5f1 smaller than the transmittance of the peripheral portion 5f2, the central portion 5f1 is made to contain a diffusing material for diffusing transmitted light, so that the transparency of the central portion 5f1 is increased. This can be realized by lowering the transparency of 5f2. By making the central part 5f1 contain more diffusing material than the peripheral part 5f2, the absorbance of the central part 5f1 is made larger than the absorbance of the peripheral part 5f2, and the central part 5f1 can absorb light more easily than the peripheral part 5f2. Thus, the transmittance of the peripheral portion 5f2 can be made larger than the transmittance of the central portion 5f1.
The material constituting the central portion 5f1 is, for example, an epoxy resin containing a diffusing material, and the material constituting the peripheral portion 5f2 is, for example, an epoxy resin having a smaller content than the central portion 5f1, thereby allowing the transmittance of the central portion 5f1 to be increased. 85%, and the transmittance of the peripheral portion 5f2 is 95%. The transmittance of the central portion 5f1 is set to, for example, 50% or more and 90% or less. The transmittance of the peripheral portion 5f2 is set to 90% or more and 98% or less, for example. The diffusion material is made of, for example, titanium oxide, aluminum oxide, barium sulfate, calcium carbonate, or the like.

  According to this embodiment, by making the transmittance of the peripheral portion 5f2 of the translucent cover 5 larger than the transmittance of the central portion 5f1, a gradation that tends to occur at the boundary between the central portion and the peripheral portion in the irradiation region is obtained. It is possible to provide the lighting device 1 that can reduce the difference and can make the gradation of the irradiation region more natural.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. When the internal space is formed as a single space, the first substrate 2 and the second substrate 3 that are integrally formed may be installed and fixed on the bottom surface of the housing 6. The first substrate 2 and the second substrate 3 that are integrally formed are integrally formed with the respective light guide holes 7h so as to surround the semiconductor light emitting elements 4 mounted in a plurality of rows on the upper surface. The reflector 7 is installed and fixed. As a result, the process of installing and fixing the first board 2 and the second board 3 to the housing 6 and the process of installing and fixing the reflector 7 to each of the first board 2 and the second board 3 are omitted, and the manufacturing lead time is eliminated. Can be shortened and the manufacturing cost can be reduced. The central portion 5f1 may be formed in parallel to the light emitting surface of the semiconductor light emitting element 4. As a result, the light emitted from the light emitting surface of the semiconductor light emitting element 4 is refracted outward on the upper surface of the central portion 5f1, and the gradation difference that tends to occur at the boundary between the central portion and the peripheral portion in the irradiation region is reduced. Therefore, it is possible to provide the lighting device 1 that can make the gradation of the irradiation region more natural. In addition, the plate body 8 does not need to be installed and fixed to the housing 6, the lighting device 1 can be normally operated, and the manufacturing cost of the lighting device 1 can be suppressed. Further, the transparent cover 5 may be installed and fixed to the housing 6 by inserting a flange formed at an end portion in the longitudinal direction into a groove formed along the longitudinal direction of the inner peripheral surface of the housing 6. The peeling of the transparent cover 5 that occurs with the deterioration of the bonding strength due to the aging deterioration of the bonding material 10 is suppressed, and the lighting device 1 can be operated normally over a long period of time.

<Manufacturing method of lighting device>
Here, a method of manufacturing the lighting device shown in FIG. 1 will be described. First, a plurality of semiconductor light emitting elements 4 are prepared. When the chip mounting substrate 41 and the frame body 43 are made of, for example, an aluminum oxide sintered body, an organic binder, a plasticizer, a solvent, or the like is added to and mixed with the aluminum oxide raw material powder to obtain a mixture.

  In the chip mounting substrate 41, the mixture is formed into a sheet-like ceramic green sheet. The frame body 43 is filled with the mixture in the mold and dried, and the chip mounting substrate 41 and the frame body 43 before sintering are taken out. .

  Moreover, a high melting point metal powder such as tungsten or molybdenum is prepared, and an organic binder, a plasticizer, a solvent, or the like is added to and mixed with the powder to obtain a metal paste. And it prints with a predetermined pattern on the ceramic green sheet used as the chip | tip mounting board | substrate 41 taken out, a several ceramic green sheet is laminated | stacked, it bakes, and it cut | disconnects to a predetermined shape. The frame body 43 is formed by sintering at a desired temperature.

Next, after the light emitting element 42 is electrically mounted on the wiring pattern on the chip mounting substrate 41 via solder, the frame body 43 is placed on the substrate via an adhesive such as acrylic resin so as to surround the light emitting element 42. Glue. Then, the sealing member 44 is formed by filling the region surrounded by the frame body 43 with, for example, a silicone resin and curing the silicone resin.

  Next, the wavelength conversion member 46 is prepared. The wavelength conversion member 46 can be produced by mixing a phosphor with an uncured resin and using a sheet forming technique such as a doctor blade method, a die coater method, an extrusion method, a spin coating method, or a dip method. Further, for example, the wavelength conversion member 46 can be obtained by filling the mold with the uncured wavelength conversion member 46 and curing it.

  And the semiconductor light emitting element 4 is producible by adhere | attaching the prepared wavelength conversion member 46 on the frame 43 through the adhesive member 45 which consists of resin, for example.

  Furthermore, the elongate 1st board | substrate 2 and the 2nd board | substrate 3 are prepared. As the first substrate 2 and the second substrate 3, for example, a printed wiring board can be used. A plurality of semiconductor light emitting elements 4 can be electrically mounted on the first substrate 2 and the second substrate 3 via solder.

  Next, the housing | casing 6, the reflector 7, and the translucent cover 5 are prepared. The housing 6 is made of aluminum, and is integrally formed in a desired shape by, for example, molding.

  The reflector 7 is made of polycarbonate, for example, and is formed into a desired shape by an extrusion method. For the reflector 7, for example, an aluminum material is used to form a vapor deposition film on the inner peripheral surface of the light guide hole 7h, so that the surface of the reflector 7 can be made a reflective surface that easily reflects light.

  The translucent cover 5 is molded by an acrylic resin containing a diffusion material whose center portion 5f1 is made of calcium carbonate. Then, after the peripheral portion 5f2 is molded with an acrylic resin that does not contain a diffusing material, the central portion 5f1 and the peripheral portion 5f2 can be bonded to each other with an adhesive made of a transparent acrylic resin so as to be formed into a desired shape. .

  And the 1st board | substrate 2 and the 2nd board | substrate 3 which mounted the semiconductor light-emitting device 4 are mounted in the housing | casing 6, and the reflector 7 is provided on each board | substrate. Furthermore, the illuminating device 1 can be produced by providing the plate body 8 on the reflector 7 and further bonding the translucent cover 5 on the housing 6 via the bonding material 10.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 1st board | substrate 3 2nd board | substrate 4 Semiconductor light-emitting device 41 Chip mounting board | substrate 42 Light-emitting device 43 Frame 44 Sealing member 45 Adhesive member 46 Wavelength conversion member 5 Translucent cover 5f1 Center part 5f2 Peripheral part 6 Case 6a Bulkhead 7 Reflector 7a Claw part 7h Light guide hole 8 Plate body 9 Electrical wiring 10 Bonding material L Wiring groove

Claims (6)

A long first substrate;
An elongated second substrate provided adjacently along a longitudinal side of the first substrate;
A plurality of light emitting elements respectively provided on the first substrate and the second substrate along the longitudinal direction of both substrates;
An elongate translucent cover provided along the longitudinal direction on the first substrate and the second substrate so as to cover the plurality of light emitting elements;
The translucent cover is an illuminating device characterized in that, in a cross section perpendicular to the longitudinal direction, the transmittance of a peripheral portion located in a peripheral region of the central portion is larger than the transmittance of the central portion. The lighting device according to claim 1,
The lighting device according to claim 1, wherein the plurality of light emitting elements are not arranged at a position overlapping the central portion of the translucent cover in a plan view. The lighting device according to claim 1 or 2,
The illuminating device, wherein the translucent cover is convexly curved upward in a cross section orthogonal to the longitudinal direction. A lighting device according to any one of claims 1 to 3,
An illuminating device, wherein a reflector having a plurality of light guide holes surrounding each of the plurality of light emitting elements is provided on the first substrate and the second substrate. A lighting device according to any one of claims 1 to 4,
The light-emitting device according to claim 1, wherein the translucent cover has a refractive index at the central portion larger than a refractive index at the peripheral portion. A lighting device according to any one of claims 1 to 4,
The light-transmitting cover includes a diffusing material for diffusing transmitted light in the central portion.

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