JP2006173286A - Optical output detection system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable irregularities in the optical output of an optical source composed of light emitting devices to be easily ascertained. <P>SOLUTION: An optical output detection system includes the optical source composed of light emitting devices; a light conversion member which contains fluorescent material that absorbs a part of light emitted from the light source and emits light having different wavelengths; and an optical output detecting means which is capable of discriminating light emitting devices having different optical outputs from the other light emitting devices. The optical output detection system is capable of discriminating the light emitting devices having different optical outputs from the other light emitting devices, based on an optical output from the light conversion member interposed between the optical output detection means and the above optical source. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light-emitting device in which a plurality of light-emitting elements are mounted, and more particularly to a light output detection system for examining variations in light output of each light-emitting element in a planar light source.

  In recent years, light-emitting elements such as light-emitting diodes and laser diodes have increased in output, and a plurality of light-emitting diodes (LEDs) and laser diodes (LDs) that emit high-power light with a short wavelength such as ultraviolet rays have been mounted. It can be utilized as a light source for curing a photocurable composition.

  For example, many exposure light sources disclosed in Japanese Patent Application Laid-Open No. 2002-303988 are arranged on a mounting substrate provided with conductor wiring for supplying power to the light emitting diodes. The light emitting diode in the present invention is a nitride semiconductor light emitting device having an emission peak wavelength of 200 nm to 400 nm. By using such an exposure light source, a wide range of exposure can be performed using light with uniform illuminance.

  By the way, it is difficult for a light emitting element such as a light emitting diode or a laser diode formed by making a semiconductor wafer into chips to form a uniform film in each region of the semiconductor lamination surface of the semiconductor wafer. Therefore, even in a light-emitting element that is made into a chip, various variations occur for each light-emitting element, such as light-emitting efficiency and light-emission output. Further, such a light emitting element gradually decreases in light emission output as it is used for a long time, but the degree of decrease in light emission output differs for each light emitting element.

JP 2002-303988 A.

  As described above, a light source on which a plurality of light emitting elements are mounted cannot irradiate a predetermined irradiated region with a uniform light intensity due to a decrease in the output of some light emitting elements. There is. Further, when the light output is reduced in some of the plurality of light emitting elements, the unevenness of curing of the photocurable composition occurs, which leads to a decrease in quality of a product formed from the photocurable composition. Therefore, out of the light-emitting elements that make up the light source, immediately detect how much the light output of the mounted light-emitting element is decreasing, and determine when to take measures such as replacing the light source with a new light source. There is a need.

  However, it is extremely difficult to detect how much the light output of the light emitting elements mounted is lowered by observing a light source in which a plurality of light emitting elements are mounted with high density. In addition, it is difficult to recognize the presence or absence of a light emitting element that outputs light with another light emitting element and whose light output has decreased by a certain value or more. In addition, it is necessary to detect a variation in light output safely and reliably for a light source including a light emitting element that emits ultraviolet rays.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for reliably detecting the degree of variation in light output of each light emitting element in a light source composed of a plurality of light emitting elements with simple means.

  In order to achieve the above object, a light output detection system according to the present invention includes a light source comprising a plurality of light emitting elements and a fluorescent material that emits light having a different wavelength by absorbing at least part of the light from the light source. And a light output detection means for detecting light emission of the light conversion member, and an identification means for identifying a light emitting element having a different light output among the plurality of light emitting elements based on an output from the light output detection means It is characterized by providing.

  Thereby, in a light source composed of a plurality of light emitting elements, a light emitting element having a light output different from that of other light emitting elements can be identified, and the degree of variation or the degree of variation of the light output of each light emitting element can be easily confirmed.

  The fluorescent substance includes a plurality of types of phosphors having different emission spectra. Accordingly, it is possible to easily detect the degree of variation in light output of each light emitting element in a light source composed of a plurality of light emitting elements. In other words, since various phosphors have different emission colors and emission intensities depending on the intensity of the output light from the light emitting element, the degree of change in the light output of the light emitting element can be detected by using a light conversion member that combines various phosphors. Can be easily done.

  The light conversion member is preferably formed by molding a resin containing the fluorescent material into a sheet shape. Thereby, it becomes easy to interpose a light conversion member between a light source and a light output detection means. Further, a plurality of types of phosphors having different emission spectra can be used as phosphor sheets containing different light conversion members, and the light output can be detected by appropriately selecting and combining these phosphor sheets.

  The light source includes a nitride semiconductor light emitting element having an emission peak wavelength of 300 nm to 450 nm. Accordingly, it is possible to detect the variation in the light output safely and reliably for the light source including the light emitting element that emits light including ultraviolet rays.

  In addition, the fluorescent material is alkaline earth silicate phosphor, alkaline earth halogen apatite phosphor, alkaline earth borate halogen phosphor, alkaline earth aluminate phosphor, rare earth aluminate phosphor, It has at least one phosphor selected from rare earth oxysulfide phosphors and organic complex phosphors. Thereby, it is possible to identify light emitting elements having different light outputs from other light emitting elements, and to easily detect variations in the light output of each light emitting element.

  The light output detection means is a CCD camera or a light receiving element arranged to correspond to the plurality of light emitting elements. Thereby, even in a light source in which light emitting elements are mounted with high density, it is possible to accurately identify light emitting elements having different light outputs from other light emitting elements, and to accurately detect variations in the light output of each light emitting element.

  The fluorescent material can be a phosphorescent fluorescent material. The phosphorescent phosphor may be at least one phosphor selected from sulfide phosphors, aluminate phosphors, aluminate phosphors containing boron, and oxysulfide phosphors. it can. Accordingly, it is possible to accurately identify a light emitting element having a light output different from that of other light emitting elements, and to accurately detect variations in the light output of each light emitting element.

  The present invention is also a light output detection method for identifying light emitting elements having different light outputs among a plurality of light emitting elements, wherein the light emitting element absorbs at least part of the light from the light emitting elements and emits light having different wavelengths. A light emitting element having a different light output among the plurality of light emitting elements is identified by a light output from the light conversion member containing the substance. Further, the light output from the light conversion member is preferably detected by a CCD camera or a light receiving element arranged to correspond to the plurality of light emitting elements.

  Thereby, in a light source composed of a plurality of light emitting elements, it is possible to identify light emitting elements having different light outputs from other light emitting elements, and to easily check the variation in the light output of each light emitting element.

  The present invention recognizes light emitted from a light source in which a plurality of light emitting elements are arranged by converting the wavelength of the light using a fluorescent material, thereby identifying a light emitting element having a lower light output than other light emitting elements. Can be easily done. Alternatively, in a light source in which a plurality of light emitting elements are arranged, it can be easily confirmed whether there is a light emitting element whose light output is lower than that of other light emitting elements. Therefore, by using the detection system according to the present invention, a light source in which a plurality of light emitting elements are arranged can be used with high reliability.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below illustrates the light output inspection method for embodying the technical idea of the present invention, and the present invention does not limit the light output inspection method to the following. Further, the size and positional relationship of the members shown in the drawings are exaggerated for clarity of explanation.

  It is extremely difficult to detect how much the light output of the mounted light emitting element is reduced by visually observing the irradiation source which is a surface light source in which a plurality of light emitting elements are mounted with high density. It is. In addition, it is necessary to detect a variation in light output safely and reliably for a light source including a light emitting element that emits ultraviolet rays. In order to solve such a problem, the present inventors have conducted various studies, and as a result, have found the means for solving the problems described below and have come to the present invention.

  That is, a light output detection system according to the present invention includes a light source composed of a plurality of light emitting elements, a light conversion member containing a fluorescent material that absorbs at least part of light from the light emitting elements and emits light having a different wavelength, and And a light output detecting means for detecting light emission of the light converting member, and an identifying means for identifying light emitting elements having different light outputs among the plurality of light emitting elements.

  In the light output detection system according to the present invention, the fluorescent substance contained in the light conversion member is fluorescent due to a difference in light output (for example, emission intensity, emission spectrum, or emission peak wavelength) from a light source serving as an excitation energy source. Output, for example, emission intensity, hue, chromaticity, color tone, or light and shade are different. Accordingly, a light-emitting element having a light output different from that of other light-emitting elements also has a fluorescence output whose wavelength is converted from that of the light-emitting element. As a result, in a light source composed of a plurality of light emitting elements, light emitting elements whose light outputs are different from those of other light emitting elements are identified by fluorescence from the corresponding light conversion member, and the variation in light output of each light emitting element can be easily performed. Can be detected. Or the presence or absence of the light emitting element from which the light output fell among the several light emitting elements which comprise a light source to below predetermined value from other light emitting elements is confirmed. It is possible to efficiently take measures such as replacing the light source with a new light source.

  The fluorescent substance in this embodiment can include a plurality of types of phosphors having different emission spectra. Examples of such phosphors include alkaline earth silicate phosphors, alkaline earth halogen apatite phosphors, alkaline earth borate halogen phosphors, alkaline earth aluminate phosphors, and rare earth aluminate phosphors. It is preferable to use at least one phosphor selected from a phosphor, a rare earth oxysulfide phosphor, or an organic complex phosphor.

  Thus, by using a plurality of types of phosphors as the fluorescent material, it is possible to easily detect the degree of variation in the light output of each light emitting element in the light source composed of a plurality of light emitting elements. That is, the various phosphors described above have different emission colors and emission intensities depending on the emission intensity and emission spectrum of the output light from the light emitting element. Therefore, a light emitting element having a different light output compared to other light emitting elements is identified by fluorescence from a light conversion member in which various phosphors are combined, and a change in light output of the light emitting element (emission intensity, emission peak wavelength or The degree of change in the emission spectrum can be roughly known.

  It is preferable that the light conversion member in this embodiment is a member obtained by molding the light-transmitting member containing the fluorescent material into a sheet shape. The translucent member containing such a fluorescent material is, for example, a translucent inorganic member such as highly light-resistant glass or quartz, or a highly translucent translucent member such as silicone resin, polycarbonate resin, or acrylic resin. It can be a resin. This makes it easy to interpose the light conversion member between the light source and the light output detection means while appropriately adjusting the distance between them. Moreover, it is possible to easily detect the light output by appropriately selecting and combining a plurality of types of phosphors having different emission peak wavelengths into different light conversion members. By appropriately selecting from these various phosphor sheets and outputting fluorescence, not only light emitting elements with different light outputs are identified, but also changes in the light output of the light emitting elements (emission intensity, emission peak wavelength or light emission). The degree of change in the spectrum can be roughly known.

  In addition, by arranging the light emitting surface of the planar light source and the main surface of the phosphor sheet to be substantially parallel, the shortest distance from the light emitting surface of the light emitting element constituting the planar light source to the main surface of the phosphor sheet. It is preferable to make the distance equal for each light emitting element and reduce the optical path length difference. Thereby, it is possible to more accurately identify light emitting elements having different light outputs. Moreover, it is preferable to adjust suitably the space | interval of a light source and a light conversion member so that the fluorescence corresponding to each light emitting element can each be recognized.

  The fluorescent substance in this embodiment can be a phosphorescent fluorescent substance. Since phosphorescent phosphors have a long afterglow time compared to other phosphors, the light output is visually different from other light emitting elements without the need for a highly sensitive CCD camera or light receiving element. It is possible to accurately identify the light emitting elements and accurately detect the variation in the light output of each light emitting element. As such a phosphorescent phosphor, for example, at least one phosphor selected from a sulfide phosphor, an aluminate phosphor, an aluminate phosphor having boron, or an oxysulfide phosphor is used. be able to. Hereinafter, each structural member in this form is explained in full detail.

[Light output detection means, identification means]
The light output detection means in the present embodiment outputs an electric signal or the like in response to the light output of each light emitting element. As such light output detection means, for example, a CCD camera or a light receiving element arranged so as to correspond to a plurality of light emitting elements constituting a light source can be used.

  The identifying means in this embodiment is a means for receiving a light signal output from the light output detecting means and identifying a light emitting element whose light output is outside the allowable range among a plurality of light emitting elements constituting the light source. It is. That is, among the plurality of light emitting elements constituting the light source, the light output having a light output smaller than (or larger than) the other light emitting elements is identified, or among the plurality of light emitting elements, the light output is smaller than the other light emitting elements ( Or the presence or number of light emitting elements). Examples of such identification means include an arithmetic processing device such as a computer. In addition, when using arithmetic processing units, such as a computer, as an identification means in this form, a video monitor etc. can be utilized as a recognition means for displaying the output result visually, for example.

  FIG. 1 is a schematic diagram of a light output detection system in the present embodiment. As an example in which the light output detecting means is a CCD camera, as shown in FIG. 1, there is one in which a CCD camera 50 photographs the state of the light emission distribution of the light conversion member 30. Further, the image signal output from the CCD camera 50 by photographing is transmitted to the image processing apparatus, and the light emitted from the light conversion member is displayed on the image monitor screen as it is for confirmation. Alternatively, the image processing device 70 such as a computer performs predetermined arithmetic processing on the video signal transmitted to the image processing device as image data, and the dot pattern is color-coded for each light emission intensity so that it can be easily recognized by humans. May be visually displayed on the video monitor 60. Here, the allowable value of the difference (light output variation) between the light output of one light-emitting element and the light output of another light-emitting element is stored in advance in the arithmetic processing unit, and compared with the actually measured light output difference. It is also possible to display a light emitting element that exceeds an allowable value. Further, the present invention is not limited to the form in which the recognition means is displayed on the video monitor screen as described above, and the light output is within an allowable range by printing, sound, warning lamp, warning buzzer, etc., or a combination thereof. It is also possible to recognize the presence or absence of a light emitting element that has become outside, or a state in which the number of light emitting elements whose light output is outside the allowable range exceeds a certain number. Thereby, even in a light source in which light emitting elements are mounted with high density, it is possible to accurately identify light emitting elements having different light outputs from those of other light emitting elements. Alternatively, an image taken with a CCD camera or a normal camera is used as a photographic film. By confirming this photographic film, light emitting elements having different light outputs from other light emitting elements can be easily identified by a simple method.

  As an example in which the light output detection means is a light receiving element, the light receiving elements can be arranged in a dot matrix so as to correspond to the arrangement of the light emitting elements. That is, the output voltage of each light receiving element corresponding to each light emitting element is measured, and the light receiving element that exceeds the allowable value compared with the output voltage of the other light receiving elements is specified. Thereby, the light emitting element corresponding to the light receiving element is specified, and the light emitting element whose light output is outside the allowable range can be specified.

  Here, it is preferable to arrange the light emitting surface of the planar light source, the main surface of the light conversion member that is a phosphor sheet, and the light incident surface of the light receiving element to be substantially parallel. Thereby, the shortest distance from the light emitting surface of the light emitting element which comprises a planar light source, the main surface of a fluorescent substance sheet, and the light-incidence surface of a light receiving element is made equal for every light emitting element. In this way, by reducing the difference in optical path length from the light emitting element to the light receiving element for each light emitting element, it is possible to more accurately identify light emitting elements having different light outputs.

  Further, by measuring the output voltage of each light receiving element, it is possible to know how much the light output of the light emitting element corresponding to the light receiving element has changed compared to when the light source started to be used. That is, first, the initial value of the output voltage of the light receiving element corresponding to the light output of each light emitting element is measured in advance. Here, the initial value measured in advance may be stored in storage means (for example, a memory) provided in the arithmetic processing unit 70 such as a computer. Next, at the time of the light output variation inspection of the light source, the output voltage for each light receiving element irradiated with light from the light source is measured. Here, the output voltage for each light receiving element may be directly input to the arithmetic processing unit 70 such as a computer as measurement data. Furthermore, the output voltage of each light receiving element at the time of the inspection of the light source is compared with an initial value measured in advance to confirm the degree of change. Alternatively, a predetermined arithmetic process is performed on the measurement data by an arithmetic processing unit 70 such as a computer, and a dot pattern or the like color-coded for each predetermined change amount is visually displayed on the video monitor 60 so as to be easily recognized by humans. It may be displayed. Thereby, it is also possible to know how much the light output of the light emitting element corresponding to the light receiving element has changed compared to when the light source is used.

  In this way, by using a CCD camera or a light receiving element as the light output detection means, even in a light source in which light emitting elements are mounted at high density, light emitting elements whose light outputs are different from those of other light emitting elements are accurately confirmed, and each light emitting element It is possible to accurately detect the variation in the light output of the element, and to use the light source with high reliability.

  It goes without saying that the light output detection means according to the present embodiment and the identification means for identifying light emitting elements having different light outputs among the plurality of light emitting elements can be combined with those means and visually observed by a human. Yes. Thereby, it is possible to easily detect the variation in the light output of each light emitting element and the presence or absence of the light emitting element whose output is reduced, and the light source can be used with high reliability.

[light source]
FIG. 2 is a schematic perspective view of a light source in the present embodiment. As shown in FIG. 2, the light source in this embodiment is a planar light source in which light emitting elements are arranged in a dot matrix. Here, each light emitting element may be arranged on a support such as a metal package or a ceramic package having high light resistance, or a package in which lead electrodes are insert-molded with a molding resin. Each light emitting element or the light emitting element mounted on the support is electrically connected to a conductor wiring provided on a substrate on which the light emitting element is mounted, and power is supplied from an external power source. For example, the light source includes a plurality of nitride semiconductor light emitting elements having an emission peak wavelength of 300 nm to 450 nm. With respect to a light source composed of a light emitting element that emits light including such ultraviolet rays, the present invention can detect variations in light output safely and reliably.

  Thus, the following matters are mentioned as an advantage of the light source which consists of a light emitting element. (1) Unlike mercury lamps, the irradiation light itself from the light source does not have heat. Therefore, thermal deformation and thermal deterioration of the irradiated object do not occur. (2) Immediately after the power is turned on, light irradiation can be performed without requiring a waiting time like a mercury lamp. (4) By using a light emitting element, it is possible to reduce the size and power consumption of the apparatus. (5) The light-emitting element has a faster response speed than a mercury lamp and can be irradiated with light by pulse driving. Hereinafter, a semiconductor light-emitting element that can constitute the light source in this embodiment will be described in detail.

(Semiconductor light emitting device)
The semiconductor light emitting element in this embodiment can be a light emitting diode or a laser diode. Here, a light emitting diode (LED chip) will be described as an example of a semiconductor light emitting element. Examples of the semiconductor light-emitting element constituting the LED chip include those using various semiconductors such as ZnSe and GaN. Nitride semiconductors (In _X Al _Y Ga ₁ -1) capable of emitting high-power light with a short wavelength can be _{exemplified. X-YN} , 0≤X, 0≤Y, X + Y≤1) are preferred. Moreover, such short wavelength high output light can efficiently excite the fluorescent substance contained in the light conversion member.

  Examples of the semiconductor structure in the semiconductor light emitting device include a homostructure having a MIS junction, a PIN junction, a pn junction, etc., a heterostructure, or a double hetero configuration. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal. In addition, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film in which a quantum effect is generated can be used.

  When a nitride semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO or the like is preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate by MOCVD or the like. A buffer layer of GaN, AlN, GaAlN or the like is formed on the sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon.

  As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer formed of n-type gallium nitride, a first clad layer formed of n-type aluminum nitride / gallium on a buffer layer, Examples include a double hetero structure in which an active layer formed of indium / gallium nitride, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked. .

  Nitride semiconductors exhibit n-type conductivity without being doped with impurities. When forming a desired n-type nitride semiconductor, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, the p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to reduce resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant.

  The p-type semiconductor layer is provided with a diffusion electrode for spreading the current input to the light emitting element over the entire surface of the p-type semiconductor layer. Furthermore, a p-side pedestal electrode and an n-side pedestal electrode connected to a conductive member such as a bump or a conductive wire are provided on the diffusion electrode and the n-type semiconductor layer, respectively. Here, examples of the material of the bump include Au, Au—Sn eutectic, and lead-free solder. Moreover, as a material of an electroconductive wire, the fine wire which consists of Al, Au, Cu, or the alloy containing them is mentioned, for example.

  The diffusion electrode, the p-side pedestal electrode, and the n-side pedestal electrode are formed by an evaporation method or a sputtering method after exposing the n-type semiconductor by a method such as etching. Further, the shape of the diffusion electrode or the p-side pedestal electrode may be various shapes so that the current spreads uniformly over the entire surface of the light emitting element.

  In this embodiment, the material for the p-side and n-side pedestal electrodes preferably contains at least one of the materials contained in the bumps and conductive wires. That is, when the bump or the conductive wire is made of Au, the material of the p-side and n-side pedestal electrode, particularly the uppermost layer that becomes the bonding surface with the bump or the conductive wire is Au or an alloy containing Au. And For example, the p-side and n-side pedestal electrodes are made of W / Pt / Au or Rh / Pt / Au, and the thickness of each metal is several hundred to several thousand. In this specification, the symbol “A / B” indicates that the metal A and the metal B are sequentially laminated by a method such as sputtering or vapor deposition.

  The diffusion electrode formed on the entire surface of the p-type semiconductor layer is preferably made of a material that reflects light emitted from the light-emitting element toward the light-transmitting substrate of the light-emitting element. For example, Ag, Al, Rh, Rh / Ir can be mentioned. Furthermore, in combination with these materials, or alone, an oxide conductive film such as ITO (complex oxide of indium (In) and tin (Sn)), ZnO, Ni / Au, etc. on the entire surface of the p-type semiconductor. The metal thin film can be formed as a translucent electrode.

  A semiconductor light emitting device according to another embodiment is composed only of a nitride semiconductor layer, and counter electrodes are formed on the upper surface and the lower surface of the semiconductor layer. The semiconductor light emitting element having such a counter electrode is fixed via a conductive adhesive so that one electrode faces the support substrate according to this embodiment. Therefore, one electrode of the light emitting element is electrically connected to the conductor wiring of the support substrate, and the other electrode is connected to the conductor wiring having a polarity different from that of the conductor wiring through the conductive wire. Examples of the material for the conductive adhesive include silver paste, and eutectic materials such as Au—Sn and Ag—Sn.

  Hereinafter, a method for forming a semiconductor light emitting device having such a counter electrode structure will be described. First, after laminating an n-type nitride semiconductor layer and a p-type nitride semiconductor layer in the same manner as the semiconductor element described above, an insulating film is formed on the p-type nitride semiconductor layer other than the p-electrode serving as the first electrode and the p-electrode. Form. On the other hand, a support substrate to be bonded to the semiconductor layer is prepared. Specific materials for the support substrate include Cu—W, Cu—Mo, AlN, Si, SiC, and the like. A structure having an adhesion layer, a barrier layer, and a eutectic layer on the bonding surface is preferable. For example, a metal film such as Ti—Pt—Au or Ti—Pt—AuSn is formed. Such a metal film is alloyed by eutectic and becomes a conductive layer in a later step.

  Next, the surface of the support substrate on which the metal film is formed and the surface of the nitride semiconductor layer face each other, heat is applied while pressing and alloyed, and then an excimer laser is irradiated from the different substrate side or by grinding. Remove the dissimilar substrate. Thereafter, outer peripheral etching is performed by RIE or the like in order to form a nitride semiconductor element, thereby obtaining a nitride semiconductor element in a state where the outer peripheral nitride semiconductor layer is removed. In order to improve the light extraction effect, the exposed surface of the nitride semiconductor may be roughened (dimple processing) by RIE or the like. The cross-sectional shape of the unevenness includes a mesa shape and an inverted mesa shape, and the planar shape includes an island shape, a lattice shape, a rectangular shape, a circular shape, a polygonal shape, and the like. Next, an n electrode as a second electrode is formed on the exposed surface of the nitride semiconductor layer. Examples of the electrode material include Ti / Al / Ni / Au and W / Al / WPt / Au.

[Light conversion member]
The fluorescent substance contained in the light conversion member of the present embodiment absorbs a part of visible light or ultraviolet light emitted from the light emitting element, and emits light having a wavelength different from the wavelength of the absorbed light. is there. In particular, the phosphor of this embodiment refers to a phosphor that emits light that has been wavelength-converted by being excited by at least light emitted from a semiconductor light emitting element, and constitutes a light conversion member together with a binder that fixes the phosphor.

  The light conversion member of this embodiment is arranged at a position where it can receive light output from the light source. In particular, the light conversion member of this embodiment is preferably interposed between the light output detection means and the light source. This is because light emitted from the light conversion member can be output to the light detection means without being affected by light output from the light source. Needless to say, the light output detecting means only needs to be disposed at a position where light emission of the light conversion member can be detected. For example, in the light conversion member that is a phosphor sheet, the light emission on the surface side that is irradiated with light from the light source may be detected by the light output detection means disposed on the light source side. Thereby, it is possible to safely and easily check the variation in the light output of the light emitting element with respect to the light source that irradiates light of short wavelength such as ultraviolet rays.

  As the binder in the light conversion member of this embodiment, for example, a light-transmitting resin such as an epoxy resin or a highly light-resistant silicone resin, or a light-transmitting inorganic material generated by a sol-gel method using a metal alkoxide as a starting material Or it can be made of glass.

  Moreover, the application method of a fluorescent substance and a binder can be made into various formation methods, such as screen printing, inkjet coating, potting, and stencil printing. For example, the light conversion member is formed by applying a fluorescent material and a binder to a plate material made of quartz, glass, or a translucent resin by the above forming method. Or it can also be set as the light conversion member which was contained in translucent resin like glass, an epoxy resin, and a silicone resin with high light resistance, and shape | molded in the sheet form. Hereinafter, the fluorescent substance that can be contained in the light conversion member of this embodiment will be described in detail.

<Aluminum garnet phosphor>
Examples of rare earth aluminate-based phosphors include the following aluminum / garnet phosphors and lutetium / aluminum / garnet phosphors. The aluminum garnet-based phosphor in the present embodiment includes Al and at least one element selected from Y, Lu, Sc, La, Gd, Tb, Eu, and Sm, and one selected from Ga and In. A phosphor that contains two elements and is activated by at least one element selected from rare earth elements, and is a phosphor that emits light when excited by visible light or ultraviolet light emitted from an LED chip.

For example, YAlO ₃ : Ce, Y ₃ Al ₅ O ₁₂ : Ce, Y ₄ Al ₂ O ₉ : Ce, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce, Y ₃ (Al _{0.8 Ga 0.2) 5 O 12: Ce} , Tb 2.95 Ce 0.05 Al 5 O 12, Y 2.90 Ce 0.05 Tb 0.05 Al 5 O 12, Y 2.94 Ce 0.05 Pr _{0.01 Al 5 O 12, Y 2.90} Ce 0.05 Pr 0.05 Al 5 O 12 and the like. Further, in the present embodiment, two or more types of yttrium / aluminum oxide phosphors (hereinafter referred to as “YAG / aluminum garnet phosphors”) containing Y and activated by Ce or Pr and having different compositions. Called "system phosphor"))). In particular, at the time of high luminance and long-term use _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce (0 ≦ x <1,0 ≦ y ≦ 1, where, Re Is at least one element selected from the group consisting of Y, Gd, and La).

_{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce phosphor, for garnet structure, heat, resistant to light and moisture, the peak of the excitation spectrum can be like in the vicinity of 470nm Can do. In addition, the emission peak is in the vicinity of 530 nm, and a broad emission spectrum that extends to 720 nm can be provided.

In the light conversion member of this embodiment, the phosphor may be a mixture of two or more phosphors. That is, speaking the YAG fluorescent material described above, Al, Ga, Y, the content of La and Gd and Sm are two or more kinds of _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O ₁₂ : Ce phosphors can be mixed to increase RGB wavelength components. At present, there are variations in the emission wavelength of the semiconductor light emitting device, so that two or more kinds of phosphors can be mixed and adjusted to obtain a desired white mixed color light or the like. Specifically, by adjusting the amount of phosphors having different chromaticity points in accordance with the emission wavelength of the light emitting element, the arbitrary points on the chromaticity diagram connected between the phosphors and the light emitting element are caused to emit light. be able to.

  Blue light emitted from a light emitting device using a nitride compound semiconductor in the light emitting layer, green light emitted from a phosphor whose body color is yellow to absorb blue light, red light, When mixed color display is performed, a desired white light emission color display can be performed. In order to cause this color mixture, the light emitting device can contain phosphor powder and bulk in various resins such as epoxy resin, acrylic resin or silicone resin, and translucent inorganic materials such as silicon oxide and aluminum oxide. Such phosphors can be used in various ways depending on the application, such as dot-like and layer-like ones that are formed thin enough to transmit light from the light-emitting element. By adjusting the ratio, coating, and filling amount of the phosphor and the translucent inorganic substance and selecting the emission wavelength of the light emitting element, it is possible to provide an arbitrary color tone such as a light bulb color including white.

  In addition, by arranging two or more kinds of phosphors in order with respect to the incident light from the light emitting element, a light emitting device capable of efficiently emitting light can be obtained. That is, on a light emitting element having a reflective member, a color conversion member containing a phosphor that has an absorption wavelength on the long wavelength side and can emit light at a long wavelength, and an absorption wavelength on the longer wavelength side that has a longer wavelength. The reflected light can be used effectively by laminating a color conversion member capable of emitting light at a wavelength.

When a YAG phosphor is used, sufficient light resistance with high efficiency even when it is placed in contact with or close to a light emitting element having an irradiance of (Ee) = 0.1 W · cm ^{−2 to} 1000 W · cm ⁻² The light emitting device can be made to have the property.

  The cerium-activated YAG-based phosphor used in this embodiment and capable of emitting green light has a garnet structure and is resistant to heat, light, and moisture, and the peak wavelength of the excitation absorption spectrum is in the vicinity of 420 nm to 470 nm. Can be made. Also, the emission peak wavelength λp is near 510 nm, and has a broad emission spectrum that extends to the vicinity of 700 nm. On the other hand, the YAG phosphor that emits red light, which is an yttrium-aluminum oxide phosphor activated by cerium, has a garnet structure, is resistant to heat, light and moisture, and has a peak wavelength of 420 nm in the excitation absorption spectrum. To about 470 nm. Further, the emission peak wavelength λp is in the vicinity of 600 nm, and has a broad emission spectrum that extends to the vicinity of 750 nm.

  Of the composition of YAG phosphors with a garnet structure, the emission spectrum is shifted to the short wavelength side by substituting part of Al with Ga, and part of Y of the composition is replaced with Gd and / or La. By doing so, the emission spectrum shifts to the long wavelength side. In this way, it is possible to continuously adjust the emission color by changing the composition. Therefore, an ideal condition for converting white light emission by using blue light emission of the nitride semiconductor is provided such that the intensity on the long wavelength side is continuously changed by the composition ratio of Gd. If the substitution of Y is less than 20%, the green component is large and the red component is small, and if it is 80% or more, the redness component is increased but the luminance is drastically decreased. Similarly, the excitation absorption spectrum is shifted to the short wavelength side by substituting part of Al with Ga in the composition of the YAG phosphor having a garnet structure. By substituting a part of Gd and / or La, the excitation absorption spectrum is shifted to the longer wavelength side. The peak wavelength of the excitation absorption spectrum of the YAG phosphor is preferably on the shorter wavelength side than the peak wavelength of the emission spectrum of the light emitting element. With this configuration, when the current input to the light emitting element is increased, the peak wavelength of the excitation absorption spectrum substantially matches the peak wavelength of the emission spectrum of the light emitting element, so that the excitation efficiency of the phosphor is not reduced. Thus, a light emitting device in which the occurrence of chromaticity deviation is suppressed can be formed.

  The aluminum garnet phosphor can be manufactured by the following method. First, phosphors use oxides or compounds that easily become oxides at high temperatures as raw materials for Y, Gd, Ce, La, Al, Sm, Pr, Tb and Ga, and they are added in a stoichiometric ratio. Mix thoroughly to obtain the raw material. Or a coprecipitated oxide obtained by calcining a solution obtained by coprecipitation of oxalic acid with a solution obtained by dissolving a rare earth element of Y, Gd, Ce, La, Sm, Pr, and Tb in an acid at a stoichiometric ratio with acid; Aluminum and gallium oxide are mixed to obtain a mixed raw material. An appropriate amount of fluoride such as ammonium fluoride is mixed with this as a flux and packed in a crucible, fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a fired product, and then the fired product in water. It can be obtained by ball milling, washing, separating, drying and finally passing through a sieve. Further, in the method for manufacturing a phosphor according to another embodiment, a first firing step in which a mixture composed of a mixture of phosphor materials and a flux is mixed in the atmosphere or in a weak reducing atmosphere, and in a reducing atmosphere. It is preferable to perform the baking in two stages, which includes the second baking step performed in step (b). Here, the weak reducing atmosphere refers to a weak reducing atmosphere set to include at least the amount of oxygen necessary in the reaction process of forming a desired phosphor from the mixed raw material. By performing the first firing step until the formation of the phosphor structure is completed, blackening of the phosphor can be prevented and a decrease in light absorption efficiency can be prevented. In addition, the reducing atmosphere in the second firing step refers to a reducing atmosphere stronger than the weak reducing atmosphere. By firing in two stages in this way, a phosphor with high absorption efficiency at the excitation wavelength can be obtained. Therefore, when a light emitting device is formed with the phosphor thus formed, the amount of the phosphor necessary for obtaining a desired color tone can be reduced, and a light emitting device with high light extraction efficiency can be formed. Can do.

  Aluminum and garnet phosphors activated with two or more types of cerium having different compositions may be mixed or used independently. When the phosphors are arranged independently, it is preferable to arrange the phosphors in the order of the phosphor that easily absorbs and emits light from the light emitting element on the shorter wavelength side, and the phosphor that easily absorbs and emits light on the longer wavelength side. This makes it possible to efficiently absorb and emit light.

  The phosphors in this embodiment are aluminum / garnet phosphors represented by yttrium / aluminum / garnet phosphors and lutetium / aluminum / garnet phosphors, and phosphors capable of emitting red light, particularly nitrides. A combination with a phosphor may be used. These YAG phosphors and nitride phosphors may be mixed and contained in the light conversion member, or may be separately contained in the light conversion member composed of a plurality of layers. Hereinafter, each phosphor will be described in detail.

<Lutetium, aluminum, garnet phosphor>
The lutetium / aluminum / garnet phosphor is a general formula (Lu _1-ab R _a M _b ) ₃ (Al _1-c Ga _c ) ₅ O ₁₂ (provided that R is at least one element in which Ce is essential). The above rare earth elements, M is at least one element selected from Sc, Y, La, and Gd, and 0.0001 ≦ a ≦ 0.5, 0 ≦ b ≦ 0.5, 0.0001 ≦ a + b <1, 0 ≦ c ≦ 0.8.) For example, the composition formula is (Lu _0.99 Ce _0.01 ) ₃ Al ₅ O ₁₂ , (Lu _0.90 Ce _0.10 ) ₃ Al ₅ O ₁₂ , (Lu _0.99 Ce _0.01 ) ₃ (Al a phosphor represented by _0.5 Ga _{0.5) 5} O _12.

  The lutetium / aluminum / garnet phosphor (hereinafter sometimes referred to as “LAG phosphor”) is obtained as follows. As a phosphor raw material, a lutetium compound, a rare earth element R compound, a rare earth element M compound, an aluminum compound, and a gallium compound are used, and each compound is weighed and mixed so as to have the ratio of the above general formula, or these are mixed. Flux is added to the phosphor material and mixed to obtain a material mixture. After filling this raw material mixture into a crucible, it is fired at 1200 to 1600 ° C. in a reducing atmosphere, and after cooling, the phosphor of the present invention represented by the above general formula is obtained by dispersion treatment.

  As the phosphor raw material, an oxide or a compound such as a carbonate or hydroxide that becomes an oxide by thermal decomposition is preferably used. Moreover, the coprecipitate which contains all or one part of each metal element which comprises fluorescent substance as a fluorescent substance raw material can also be used. For example, when an aqueous solution such as alkali or carbonate is added to an aqueous solution containing these elements, a coprecipitate can be obtained, which can be used after being dried or thermally decomposed. Moreover, as a flux, a fluoride, a borate, etc. are preferable, and it adds in 0.01-1.0 weight part with respect to 100 weight part of fluorescent substance raw materials. The firing atmosphere is preferably a reducing atmosphere in which the activator cerium is not oxidized. A mixed gas atmosphere of hydrogen and nitrogen having a hydrogen concentration of 3.0% by volume or less is more preferable. The firing temperature is preferably 1200 to 1600 ° C., and a phosphor having a target center particle diameter can be obtained. More preferably, it is 1300-1500 degreeC.

  In the above general formula, R is an activator and is at least one or more rare earth elements essential for Ce, specifically, Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lr. R may be Ce alone, but may contain Ce and at least one element selected from rare earth elements other than Ce. This is because rare earth elements other than Ce act as coactivators. Here, it is preferable that Ce contains 70 mol% or more of Ce with respect to the total amount of R. The a value (R amount) is preferably 0.0001 ≦ a ≦ 0.5. If the value is less than 0.0001, the light emission luminance is lowered, and if it exceeds 0.5, the light emission luminance is lowered by concentration quenching. More preferably, 0.001 ≦ a ≦ 0.4, and still more preferably 0.005 ≦ a ≦ 0.2. The b value (M amount) is preferably 0 ≦ b ≦ 0.5, more preferably 0 ≦ b ≦ 0.4, and still more preferably 0 ≦ b ≦ 0.3. For example, when M is Y and the b value exceeds 0.5, the emission luminance due to excitation of long-wavelength ultraviolet light to short-wavelength visible light, particularly 360 to 410 nm is extremely lowered. The c value (Ga content) is preferably 0 ≦ c ≦ 0.8, more preferably 0 ≦ c ≦ 0.5, and still more preferably 0 ≦ c ≦ 0.3. When the c value exceeds 0.8, the emission wavelength shifts to a short wavelength, and the emission luminance decreases.

  The center particle size of the LAG phosphor is preferably in the range of 1 to 100 μm, more preferably in the range of 5 to 50 μm, and still more preferably in the range of 5 to 15 μm. Phosphors smaller than 1 μm tend to form aggregates. On the other hand, the phosphor having a particle size in the range of 5 to 50 μm has high light absorptivity and conversion efficiency, and easily forms a light conversion member. As described above, the mass productivity of the light-emitting device is improved by including a phosphor having a large particle diameter and having optically excellent characteristics. Moreover, it is preferable that the fluorescent substance which has the said center particle size value is contained frequently, and 20%-50% of frequency values are preferable. By using a phosphor having a small variation in particle size in this way, a light emitting device having a favorable color tone with more suppressed color unevenness can be obtained.

  Since the lutetium / aluminum / garnet phosphor is efficiently excited and emitted by ultraviolet rays or visible light in the wavelength region of 300 nm to 550 nm, it can be effectively used as a phosphor contained in the light conversion member. Furthermore, by using a plurality of types of LAG phosphors having different composition formulas or LAG phosphors together with other phosphors, the emission color of the light emitting device can be variously changed. A conventional light emitting device that emits white light by mixing blue light emitted from a semiconductor light emitting element and light emitted from a phosphor emitting yellow light by absorbing the light emitted from the light emitting element. Since part of the light is used through transmission, there is an advantage that the structure itself can be simplified and the output can be easily improved. On the other hand, since the light emitting device emits light by mixing two colors, the color rendering properties are not sufficient, and improvement is required. Therefore, a light emitting device that emits white color mixed light using a LAG phosphor can improve its color rendering as compared with a conventional light emitting device. In addition, since the LAG phosphor has excellent temperature characteristics as compared with the YAG phosphor, a light emitting device with little deterioration and color shift can be obtained.

<Nitride phosphor>
The nitride-based phosphor in the present embodiment includes N and at least one element selected from Be, Mg, Ca, Sr, Ba, and Zn, and C, Si, Ge, Sn, Ti, Zr, And at least one element selected from Hf, and a phosphor activated by at least one element selected from rare earth elements. In addition, the nitride-based phosphor in the present embodiment refers to a phosphor that emits light when excited by absorbing visible light, ultraviolet light, and light emitted from the YAG-based phosphor emitted from the LED chip.

For _{example, Sr 2 Si 5 N 8:} Eu, Pr, Ba 2 Si 5 N 8: Eu, Pr, Mg 2 Si 5 N 8: Eu, Pr, Zn 2 Si 5 N 8: Eu, Pr, SrSi 7 N 10 _{: Eu, Pr, BaSi 7 N} 10: Eu, Ce, MgSi 7 N 10: Eu, Ce, ZnSi 7 N 10: Eu, Ce, Sr 2 Ge 5 N 8: Eu, Ce, Ba 2 Ge 5 N 8: _{Eu, Pr, Mg 2 Ge 5} N 8: Eu, Pr, Zn 2 Ge 5 N 8: Eu, Pr, SrGe 7 N 10: Eu, Ce, BaGe 7 N 10: Eu, Pr, MgGe 7 N 10: Eu , Pr, ZnGe ₇ N ₁₀ : Eu, Ce, Sr _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Pr, Ba _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Ce, Mg _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Pr, Zn _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Ce, Sr _0.8 Ca _0.2 Si ₇ N ₁₀ : Eu, La, Ba _0.8 Ca _0.2 Si ₇ N ₁₀ : Eu, La, Mg _0.8 Ca _0.2 Si ₇ N ₁₀ : Eu, Nd, Zn _0.8 Ca _0.2 Si ₇ N ₁₀ : Eu, Nd, Sr _0.8 Ca _{0. 2} Ge ₇ N ₁₀ : Eu, Tb, Ba _0.8 Ca _0.2 Ge ₇ N ₁₀ : Eu, Tb, Mg _0.8 Ca _0.2 Ge ₇ N ₁₀ : Eu, Pr, Zn _0.8 Ca _{0 .2 Ge 7 N 10: Eu,} Pr, Sr 0.8 Ca 0.2 Si 6 GeN 10: Eu, Pr, Ba 0.8 Ca 0.2 Si 6 GeN 10: Eu, Pr, Mg 0.8 Ca _0.2 Si ₆ GeN ₁₀ : Eu, Y, Zn _0.8 Ca _{0. 2} Si ₆ GeN ₁₀ : Eu, Y, Sr ₂ Si ₅ N ₈ : Pr, Ba ₂ Si ₅ N ₈ : Pr, Sr ₂ Si ₅ N ₈ : Tb, BaGe ₇ N ₁₀ : Ce, etc. It is not limited. The rare earth element contained in the nitride phosphor preferably contains at least one of Y, La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, and Lu. , Sm, Tm, Yb may be contained. These rare earth elements are mixed in the raw material in the state of oxide, imide, amide, etc. in addition to simple substances. When Mn is used, the particle size can be increased, and the emission luminance can be improved.

In particular, this phosphor is composed of Sr—Ca—Si—N: Eu, Ca—Si—N: Eu, Sr—Si—N: Eu, Sr—Ca—Si—O—N: Eu, Ca to which Mn is added. —Si—O—N: Eu, Sr—Si—O—N: Eu-based silicon nitride. The basic constituent elements of this phosphor are represented by the general formula L _X Si _Y N _{(2 / 3X + 4 / 3Y)} : Eu or L _X Si _Y O _Z N _{(2 / 3X + 4 / 3Y-2 / 3Z)} : Eu (L is Sr, Ca, or any one of Sr and Ca.) In the general formula, X and Y are preferably X = 2, Y = 5, or X = 1, Y = 7, but any can be used. Specifically, the basic constituent elements, Mn is added _{(Sr X Ca 1-X)} 2 Si 5 N 8: Eu, Sr 2 Si 5 N 8: Eu, Ca 2 Si 5 N 8: Eu, Sr _{X Ca 1-X Si 7 N} 10: Eu, SrSi 7 N 10: Eu, CaSi 7 N 10: it is preferable to use a phosphor represented by Eu, during the composition of the phosphor, Mg, At least one selected from the group consisting of Sr, Ca, Ba, Zn, B, Al, Cu, Mn, Cr and Ni may be contained. L is any one of Sr, Ca, Sr and Ca. The mixing ratio of Sr and Ca can be changed as desired. By using Si for the composition of the phosphor, it is possible to provide an inexpensive phosphor with good crystallinity.

This phosphor uses Eu ²⁺ as an activator with respect to the base alkaline earth metal silicon nitride. Mn as an additive promotes diffusion of Eu ²⁺ and improves luminous efficiency such as luminous luminance, energy efficiency, and quantum efficiency. Mn is contained in the raw material, or Mn alone or a Mn compound is contained in the manufacturing process and fired together with the raw material.

  The phosphor includes Mg, Ga, In, Li, Na, K, Re, Mo, Fe, Sr, Ca, Ba, Zn, B, Al, Cu, in the basic constituent element or together with the basic constituent element. It contains at least one selected from the group consisting of Mn, Cr, O and Ni. These elements have actions such as increasing the particle diameter and increasing the luminance of light emission. Further, B, Al, Mg, Cr and Ni have an effect that afterglow can be suppressed.

  Such a nitride-based phosphor absorbs part of the light emitted by the light emitting element and emits light in the yellow to red region. Light emission using a nitride-based phosphor together with a YAG-based phosphor to emit warm white-colored light by mixing the light emitted by the light-emitting element and the yellow to red light by the nitride-based phosphor Providing the device. The phosphor added in addition to the nitride phosphor preferably contains an aluminum garnet phosphor. This is because it can be adjusted to a desired chromaticity by containing an aluminum / garnet phosphor. For example, a yttrium / aluminum oxide phosphor activated with cerium absorbs a part of the light emitting element light and emits light in a yellow region. Here, the light emitted by the light emitting element and the yellow light of the yttrium / aluminum oxide phosphor emit white mixed color light by mixing colors. Therefore, this yttrium / aluminum oxide phosphor and phosphor emitting red light are mixed together in a light-transmitting light conversion member, and the wavelength is converted by blue light emitted from the light emitting element or phosphor. In combination with blue light, a light emitting device that emits white light can be provided. Particularly preferred is a white light emitting device whose chromaticity is located on the locus of black body radiation in the chromaticity diagram. However, in order to provide a light emitting device having a desired color temperature, the amount of phosphor of the yttrium / aluminum oxide phosphor and the amount of phosphor of red light emission can be appropriately changed. This light-emitting device that emits white-based mixed color light improves the special color rendering index R9. A white light emitting device consisting only of a combination of a conventional blue light emitting element and a yttrium aluminum oxide fluorescent material activated with cerium has a special color rendering index R9 of almost 0 at a color temperature of Tcp = 4600K, which is reddish. Insufficient ingredients. For this reason, increasing the special color rendering index R9 has been a problem to be solved. However, in the present invention, the special color rendering index near the color temperature Tcp = 4600K is obtained by using the phosphor emitting red light together with the yttrium aluminum oxide phosphor. R9 can be increased to around 40.

Next, the phosphor according to the present invention: is described a method of manufacturing the _{((Sr X Ca 1-X} ) 2 Si 5 N 8 Eu), but is not limited to this manufacturing method. The phosphor contains Mn and O.

The raw materials Sr and Ca are preferably used alone, but compounds such as imide compounds and amide compounds can also be used. The raw materials Sr and Ca may contain B, Al, Cu, Mg, Mn, MnO, Mn ₂ O ₃ , Al ₂ O ₃ and the like. The raw materials Sr and Ca are pulverized in a glove box in an argon atmosphere. Sr and Ca obtained by pulverization preferably have an average particle diameter of about 0.1 μm to 15 μm, but are not limited to this range. In order to improve the mixed state, at least one of the metal Ca, the metal Sr, and the metal Eu can be alloyed, nitrided, pulverized, and used as a raw material.

The raw material Si is preferably a simple substance, but a nitride compound, an imide compound, an amide compound, or the like can also be used. For example, Si ₃ N ₄ , Si (NH ₂ ) ₂ , Mg ₂ Si, or the like. The purity of the raw material Si is preferably 3N or more, but Al ₂ O ₃ , Mg, metal borides (Co ₃ B, Ni ₃ B, CrB), manganese oxide, H ₃ BO ₃ , B ₂ O ₃ , Compounds such as Cu ₂ O and CuO may be contained. Si is also pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere in the same manner as the raw materials Sr and Ca. The average particle size of the Si compound is preferably about 0.1 μm to 15 μm.

  Next, Sr and Ca are nitrided in a nitrogen atmosphere. Sr and Ca may be mixed and nitrided, or may be individually nitrided. Thereby, a nitride of Sr and Ca can be obtained. Further, the raw material Si is nitrided in a nitrogen atmosphere. Thereby, silicon nitride is obtained.

Sr, Ca or Sr—Ca nitride is pulverized. Sr, Ca, and Sr—Ca nitrides are pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere.
Similarly, Si nitride is pulverized. Similarly, the Eu compound Eu ₂ O ₃ is pulverized. Europium oxide is used as the Eu compound, but metal europium, europium nitride, and the like can also be used. In addition, as the raw material Z, an imide compound or an amide compound can be used. Europium oxide is preferably highly purified, but commercially available products can also be used. The average particle size of the alkaline earth metal nitride, silicon nitride and europium oxide after pulverization is preferably about 0.1 μm to 15 μm.

The raw material may contain at least one selected from the group consisting of Mg, Sr, Ca, Ba, Zn, B, Al, Cu, Mn, Cr, O, and Ni. In addition, the above elements such as Mg, Zn, and B can be mixed by adjusting the blending amount in the following mixing step. These compounds can be added alone to the raw material, but are usually added in the form of compounds. Such compounds include H ₃ BO ₃ , Cu ₂ O ₃ , MgCl ₂ , MgO · CaO, Al ₂ O ₃ , metal borides (CrB, Mg ₃ B ₂ , AlB ₂ , MnB), B ₂ O ₃ , Cu ₂ O, CuO, and the like.

After the pulverization, Sr, Ca, Sr—Ca nitride, Si nitride, and Eu compound Eu ₂ O ₃ are mixed, and Mn is added. Since these mixtures are easily oxidized, they are mixed in a glove box in an Ar atmosphere or a nitrogen atmosphere.

Finally, a mixture of Sr, Ca, Sr—Ca nitride, Si nitride, and Eu compound Eu ₂ O ₃ is fired in an ammonia atmosphere. A phosphor represented by (Sr _X Ca _1-X ) ₂ Si ₅ N ₈ : Eu to which Mn is added can be obtained by firing. However, the composition of the target phosphor can be changed by changing the blending ratio of each raw material.

For firing, a tubular furnace, a small furnace, a high-frequency furnace, a metal furnace, or the like can be used. The firing temperature can be in the range of 1200 to 1700 ° C, but the firing temperature is preferably 1400 to 1700 ° C. It is preferable to use a one-step baking in which the temperature is gradually raised and the baking is performed at 1200 to 1500 ° C. for several hours, but the first baking is performed at 800 to 1000 ° C. and the heating is gradually started from 1200. Two-stage firing (multi-stage firing) in which the second stage firing is performed at 1500 ° C. can also be used. The phosphor material is preferably fired using a boron nitride (BN) crucible or boat. Besides the crucible made of boron nitride, a crucible made of alumina (Al ₂ O ₃ ) can also be used.

By using the above manufacturing method, it is possible to obtain a target phosphor. In the embodiment of the present invention, a nitride-based phosphor is used as the phosphor that emits reddish light. In the present invention, the above-described YAG-based phosphor can emit red light. It is also possible to provide a light emitting device including a simple phosphor. Such a phosphor capable of emitting red light is a phosphor that emits light when excited by light having a wavelength of 400 to 600 nm. For example, Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu. CaS: Eu, SrS: Eu, ZnS: Mn, ZnCdS: Ag, Al, ZnCdS: Cu, Al and the like. Thus, by using a phosphor capable of emitting red light together with a YAG phosphor, it is possible to improve the color rendering properties of the light emitting device.

  The phosphor capable of emitting red light typified by the aluminum garnet phosphor and the nitride phosphor formed as described above is included in the light conversion member consisting of one layer around the light emitting element. Two or more types may exist, and one type or two or more types may exist in the light conversion member which consists of two layers, respectively. With such a configuration, it is possible to obtain mixed color light by mixing light from different types of phosphors. In this case, it is preferable that the average particle diameters and shapes of the phosphors are similar in order to better mix the light emitted from the phosphors and reduce color unevenness. Also, considering that the nitride-based phosphor absorbs part of the light that has been wavelength-converted by the YAG-based phosphor, the nitride-based phosphor is disposed closer to the light emitting element than the YAG-based phosphor. It is preferable to form the light conversion member as described above. With this configuration, a part of the light wavelength-converted by the YAG phosphor is not absorbed by the nitride phosphor, and the YAG phosphor and the nitride phosphor are mixed. Compared with the case where it contains, the color rendering property of mixed-color light can be improved.

<Oxynitride phosphor>
In addition to the fluorescent material described above, the fluorescent material in the present embodiment can further contain an oxynitride phosphor represented by the following general formula.
_{L x M y O z N {} (2 / 3x + (4/3) y- (2/3) z}: R
However, L has at least one element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn, and M is from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. Having at least one element selected. N is nitrogen, O is oxygen, and R is a rare earth element. x, y, and z satisfy the following numerical values.
x = 2, 4.5 ≦ y ≦ 6, 0.01 <z <1.5
Or x = 1, 6.5 ≦ y ≦ 7.5, 0.01 <z <1.5
Or x = 1, 1.5 ≦ y ≦ 2.5, 1.5 ≦ z ≦ 2.5
Hereinafter, although the manufacturing method of oxynitride fluorescent substance is demonstrated, it cannot be overemphasized that it is not limited to this manufacturing method. First, L nitride, M nitride and oxide, and an oxide of rare earth element are mixed as raw materials so as to obtain a predetermined blending ratio. By changing the blending ratio of each raw material, the composition of the target phosphor can be changed.

Next, the mixture of the above raw materials is put into a crucible and fired. For firing, a tubular furnace, a small furnace, a high-frequency furnace, a metal furnace, or the like can be used. The firing temperature is not particularly limited, but the firing is preferably performed in the range of 1200 to 1700 ° C, more preferably 1400 to 1700 ° C. The phosphor material is preferably fired using a boron nitride (BN) crucible and boat. Besides the crucible made of boron nitride, a crucible made of alumina (Al ₂ O ₃ ) can also be used. Moreover, it is preferable to perform baking in a reducing atmosphere. The reducing atmosphere is a nitrogen atmosphere, a nitrogen-hydrogen atmosphere, an ammonia atmosphere, an inert gas atmosphere such as argon, or the like. By using the above manufacturing method, the target oxynitride phosphor can be obtained.

<Alkaline earth metal silicate>
The light-emitting device in this embodiment mode uses alkaline earth activated by europium as a phosphor that absorbs part of light emitted from a light-emitting element and emits light having a wavelength different from the wavelength of the absorbed light. It can also have a metal silicate. The alkaline earth metal silicate can be a light-emitting device that emits warm color mixed light using blue light as excitation light. The alkaline earth metal silicate is preferably an alkaline earth metal orthosilicate represented by the following general formula.
(2-x-y) SrO · x (Ba, Ca) O · (1-a-b-c-d) SiO 2 · aP 2 O 5 bAl 2 O 3 cB 2 O 3 dGeO 2: yEu 2+ ( Equation Medium, 0 <x <1.6, 0.005 <y <0.5, 0 <a, b, c, d <0.5.)
(2-x-y) BaO · x (Sr, Ca) O · (1-a-b-c-d) SiO 2 · aP 2 O 5 bAl 2 O 3 cB 2 O 3 dGeO 2: yEu 2+ ( Equation (Inside, 0.01 <x <1.6, 0.005 <y <0.5, 0 <a, b, c, d <0.5.)
Here, preferably, at least one of the values of a, b, c and d is greater than 0.01.

The light-emitting device in the present embodiment is a phosphor composed of an alkaline earth metal salt. In addition to the alkaline earth metal silicate described above, alkaline earth metal aluminate or Y activated by europium and / or manganese is used. (V, P, Si) O ₄ : Eu, or an alkaline earth metal-magnesium-disilicate represented by the following formula:

Me (3-xy) MgSi ₂ O ₃ : xEu, yMn (wherein 0.005 <x <0.5, 0.005 <y <0.5, Me represents Ba and / or Sr and / or Or Ca.)
Next, the manufacturing process of the phosphor made of alkaline earth metal silicate in the present embodiment will be described.

  For the production of alkaline earth metal silicates, the stoichiometric amounts of the starting materials alkaline earth metal carbonate, silicon dioxide and europium oxide are intimately mixed according to the selected composition, and the phosphor is produced. In a conventional solid reaction, the desired phosphor is converted at a temperature of 1100 ° C. and 1400 ° C. under a reducing atmosphere. At this time, it is preferable to add less than 0.2 mol of ammonium chloride or other halide. If necessary, part of silicon can be replaced with germanium, boron, aluminum, and phosphorus, and part of europium can be replaced with manganese.

One of the phosphors as described above, ie, alkaline earth metal aluminates activated with europium and / or manganese, Y (V, P, Si) O ₄ : Eu, Y ₂ O ₂ S: Eu ³⁺ By combining one or these phosphors, an emission color having a desired color temperature and high color reproducibility can be obtained.

<Phosphorescent phosphor>
The phosphorescent phosphor in this embodiment is, for example, at least one phosphorescent phosphor selected from a sulfide phosphor, an aluminate phosphor, an aluminate phosphor having boron, or an oxysulfide phosphor. It can be a body. Hereinafter, the phosphorescent fluorescent material will be described in detail.

  (1) A sulfide-based phosphor is composed of at least one element M selected from the group consisting of Mg, Ca, Ba, Sr, Zn and Cd, and S from Cu, Mn, Eu, Cl and Ag. A fluorescent material activated by at least one element M ′ selected from the group consisting of:

  (2) Aluminate phosphors are at least one element M selected from the group consisting of Mg, Ca, Ba, Sr and Zn, O, Al, Eu, Pr, Nd, Dy. , A fluorescent material activated with at least one element Q selected from the group consisting of Er and Ho.

  (3) The aluminate-based phosphor having boron is at least one element M selected from the group consisting of Mg, Ca, Ba, Sr and Zn, O, Al, and B, and Eu. , A phosphor having a boron activated with at least one element Q selected from the group consisting of Pr, Nd, Dy, Er and Ho.

  (4) The oxysulfide-based fluorescent material includes at least one element Ln selected from the group consisting of Y, La, Gd, and Lu, O, and S, Eu, Mg, Ti, Nb, and Ta. And a fluorescent material activated with at least one element M selected from the group consisting of Ga.

  Although the manufacturing method of the luminous fluorescent substance in this form is not specifically limited, For example, it can manufacture as follows.

1. Preparation of Raw Material Mixture Compounds described later are mixed so that each constituent element has a predetermined composition ratio to obtain a raw material mixture of a fluorescent material. The compound used for the raw material mixture of the fluorescent substance is selected according to the elements constituting the target composition.

  The mixing method is not particularly limited, for example, a method of mixing powdery compounds as they are to obtain a raw material mixture; mixing in a slurry form using water and / or an organic solvent, and then drying to obtain a raw material mixture Method: A method in which an aqueous solution of the above-mentioned compound is mixed and precipitated, and the resulting precipitate is dried to obtain a raw material mixture; a method in which these are used in combination. Below, the compound used for the raw material mixture of a luminous fluorescent substance is illustrated.

(Sulphide fluorescent materials)
The compounds of Mg, Ca, Ba, Sr, Zn, Cd, Cu, Mn, Eu, Cl, Ag, and S are not particularly limited. For example, metals, oxides, and the like can be easily converted into sulfides by reacting with S. Possible compounds are mentioned.

(In the case of aluminate phosphor)
The compounds of Mg, Ca, Ba, Sr, Zn, Eu, Pr, Nd, Dy, Er, Ho, and B are not particularly limited, and examples thereof include oxides and compounds that easily become oxides at high temperatures. .

(For oxysulfide phosphors)
The compounds of Y, La, Gd, Lu, Eu, Mg, Ti, Nb, Ta, and Ga are not particularly limited, but can easily become oxysulfides by reacting with S such as oxides and carbonates. Compounds.

2. The raw material mixture is fired and ground, and then the raw material mixture is fired. The firing temperature, time, atmosphere, and the like are not particularly limited, and can be appropriately determined according to the purpose.

  The firing temperature is preferably 800 ° C. or higher. If the firing temperature is too low, unreacted raw materials may remain in the fluorescent material and the original characteristics of the fluorescent material may not be utilized, but such a problem does not occur within the above range. Moreover, it is preferable that a calcination temperature is 1600 degrees C or less. If the firing temperature is too high, the particle size of the fluorescent material may become too large and the characteristics may deteriorate. However, such a problem does not occur within the above range.

  In general, the firing time is preferably about 1 to 20 hours. If the firing time is too short, the diffusion reaction between the raw material particles hardly proceeds, and if the firing time is too long, the firing after the diffusion reaction is almost completed is wasted, and coarse particles are formed by sintering. In some cases, such a problem does not occur within the above range.

Examples of the firing atmosphere include air, oxygen gas, a mixed gas of these with an inert gas such as nitrogen gas and argon gas, an atmosphere in which the oxygen concentration (oxygen partial pressure) is controlled, a weak oxidizing atmosphere, and a reducing atmosphere. . Here, the reducing atmosphere is a nitrogen atmosphere, a hydrogen atmosphere, a nitrogen-hydrogen atmosphere, an ammonia atmosphere, an inert gas atmosphere such as argon, or the like. Among them, a reducing atmosphere such as H ₂ and N ₂ is preferable.

  After firing, if desired, the powder may be pulverized using a rough mortar, ball mill, vibration mill, pin mill, jet mill or the like to obtain a powder having a desired particle size. It may be passed through a sieve. The phosphorescent phosphor of this embodiment can be obtained by the manufacturing method described above.

<Other phosphors>
In the present embodiment, a phosphor that emits light by being excited by light in the ultraviolet to visible region can be used as the phosphor. Specific examples include the following phosphors.
(1) Eu, Mn or alkaline earth halogen apatite phosphor activated with Eu and Mn; for example, M ₅ (PO ₄ ) ₃ (Cl, Br): Eu (where M is Sr, Ca, Ba, Phosphors such as at least one selected from Mg), Ca ₁₀ (PO ₄ ) ₆ ClBr: Mn, Eu.
(2) Eu, Mn or alkaline earth aluminate phosphor activated by Eu and Mn; for example, BaMg ₂ Al ₁₆ O ₂₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn, Sr ₄ Al ₁₄ Phosphors such as O ₂₅ : Eu, SrAl ₂ O ₄ : Eu, CaAl ₂ O ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn and the like.
(3) A rare earth oxysulfide phosphor activated with Eu; for example, a phosphor such as La ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, or Gd ₂ O ₂ S: Eu.
(4) (Zn, Cd) S: Cu, Zn ₂ GeO ₄ : Mn, 3.5 MgO · 0.5 MgF ₂ · GeO ₂ : Mn, Mg ₆ As ₂ O ₁₁ : Mn, (Mg, Ca, Sr, Ba _{) Ga 2 S 4: Eu,} Ca 10 (PO 4) 6 FCl: Sb, Mn
Hereinafter, an embodiment of the optical output detection system according to the present invention will be described in detail. Needless to say, the present invention is not limited to the following examples.

  FIG. 1 is a schematic explanatory diagram of a light output detection system according to the present embodiment. FIG. 2 is a schematic perspective view of a light source in the present embodiment.

  The light output detection system 10 according to the present embodiment includes a light source 40 composed of a plurality of light emitting diodes, and a light conversion member containing a fluorescent material that emits light having different wavelengths by absorbing at least a part of light from the light emitting diodes. 30, a CCD camera 50 that detects the light output from the light conversion member 30, an arithmetic processing unit 60 that serves as an identification means for identifying a light emitting diode whose light output is outside the allowable range among the plurality of light emitting elements, and its calculation And a video monitor 70 for displaying the output result of the processing device 60. Further, the light conversion member 30 is a phosphor sheet having a thickness of several millimeters so that it can be interposed between the light source 40 and the CCD camera 50.

  The light conversion member 30 in this embodiment is obtained by applying phosphors having different emission colors according to the light output from the light emitting diode 20 to a transparent sheet made of a translucent resin. Further, as shown in FIG. 2, the light source 40 in this embodiment is formed by arranging light emitting diodes 20 that irradiate ultraviolet rays having a wavelength of 365 nm in a dot matrix at intervals of 1 mm. Hereinafter, a method of using the light output detection system in the present embodiment will be described in detail.

  First, the light conversion member 30 is interposed between the light irradiation side of the light source 40 and the CCD camera 50. Here, the light conversion member 30 is preferably arranged so that the shortest distance from the light emitting surface of each light emitting diode 20 constituting the light source 40 to the light conversion member 30 is substantially equal. Thereby, the optical path length difference of the light emitted from each light emitting diode 20 can be reduced and more accurate identification can be performed.

  Next, electric power is supplied to the light source 40, and the light conversion member 30 is irradiated with light from the light source 40. At this time, fluorescence is emitted from each position of the light conversion member 30 corresponding to each light emitting element. Furthermore, the light conversion member 30 that emits fluorescence upon receiving light irradiation from the light source 40 is photographed by the CCD camera 50 from the opposite side to the light source 40.

  Finally, the result of photographing is output to the video monitor 70 to confirm the density distribution of the fluorescence, and the light emitting diodes whose light output is lower than the permissible value from other light emitting diodes are identified. Alternatively, it is confirmed that there is a light emitting diode in the light source whose light output has dropped below a predetermined allowable value.

  In this embodiment, a CCD camera is used as the light output detecting means 50 and the light emitting diode whose output is reduced is accurately detected. Needless to say, visual detection is also possible.

  The light conversion member in this example is obtained by applying a mixture of livestock phosphors having different light emission intensities depending on the light output from the light emitting diodes on a transparent sheet made of a light transmitting resin.

  A light conversion member is arranged on the light emission observation surface side of the light source 40 similar to that in the above-described first embodiment, and the output state of each light emitting diode is visually grasped from the shade of afterglow color of the livestock phosphor. Identify light emitting diodes whose light output is lower than other light emitting diodes.

  The light output detection system according to the present embodiment can easily grasp the output state of each light emitting diode without requiring a CCD camera as in the first embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be used as an inspection method for a light source in a field using a light source in which a plurality of light emitting elements are arranged, for example, in a technical field such as curing of a photocurable resin, exposure, and a sensor.

FIG. 1 is a schematic explanatory diagram of a light output detection system in an embodiment of the present invention. FIG. 2 is a perspective view of a light source in the light output detection system according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Light output detection system 20 ... Light emitting element 30 ... Light conversion member 40 ... Light source 50 ... Light output detection means 60 ... Arithmetic processing unit 70 ... Video monitor

Claims (10)

A light source comprising a plurality of light emitting elements;
A light conversion member containing a fluorescent material that absorbs at least part of the light from the light source and emits light having a different wavelength; and
A light output detecting means for detecting light emission of the light converting member;
An optical output detection system comprising: an identification unit that identifies a light emitting element having a different optical output among the plurality of light emitting elements based on an output from the optical output detection unit. The light output detection system according to claim 1, wherein the fluorescent material includes a plurality of types of phosphors having different emission spectra. The light output detection system according to claim 1, wherein the light conversion member is formed by forming a light transmissive member containing the fluorescent material into a sheet shape. 4. The light output detection system according to claim 1, wherein the light source includes a nitride semiconductor light emitting element having an emission peak wavelength of 300 nm to 450 nm. The fluorescent material includes alkaline earth silicate phosphor, alkaline earth halogen apatite phosphor, alkaline earth borate halogen phosphor, alkaline earth aluminate phosphor, rare earth aluminate phosphor, rare earth acid 5. The light output detection system according to claim 1, further comprising at least one phosphor selected from sulfide phosphors, nitride phosphors, oxynitride phosphors, and organic complex phosphors. 6. The light output detection system according to claim 1, wherein the light output detection means is a CCD camera or a light receiving element arranged to correspond to the plurality of light emitting elements. The light output detection system according to claim 1, wherein the fluorescent material is a phosphorescent fluorescent material. The phosphorescent phosphor comprises at least one phosphor selected from a sulfide phosphor, an aluminate phosphor, an aluminate phosphor containing boron, or an oxysulfide phosphor. The light output detection system described in 1. A light output detection method for identifying light emitting elements having different light outputs among a plurality of light emitting elements,
By light output from the light conversion member containing a fluorescent material that absorbs at least part of the light from the light emitting element and emits light having a different wavelength,
A light output detection method comprising: identifying light emitting elements having different light outputs among the plurality of light emitting elements. The light output detection method according to claim 9, wherein the light output from the light conversion member is detected by a CCD camera or a light receiving element arranged to correspond to the plurality of light emitting elements.

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