JP2012079989A - Light source device and lighting fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow sufficiently higher brightness than before, and to prevent color unevenness in an emission point of a phosphor layer.SOLUTION: The light source device includes a solid light source 5 which emits light in a predetermined wavelength among the wavelength region from ultraviolet light to visible light, and a phosphor layer 2 containing at least one kind of phosphor which is excited by the excitation light from the solid light source 5 to emit fluorescence of the wavelength longer than the emission wavelength of the solid light source 5, with the solid light source 5 and the phosphor layer 2 being arranged away from each other in terms of space. The phosphor layer 2 is attached on a light reflecting stage 6 of truncated pyramid shape or truncated cone shape. The light reflecting stage 6 is attached to a light absorbing member 9. The shape and cross sectional area of the beam, which is the excitation light from the solid light source 5 that enters the phosphor layer 2 attached on the light reflecting stage 6, on the incidence surface of the phosphor layer is similar to the shape and area of the entire incidence surface of the phosphor layer.

Description

  The present invention relates to a light source device and an illumination device.

  A light source device combining an optical semiconductor such as an LED and a phosphor layer has been widely used. However, in recent years, the brightness has been increased, and its application range such as general lighting and automobile headlamps has been expanded. It is considered that such light source devices will continue to be widely used in various applications by increasing the luminance.

  As a means for increasing the brightness of a light source device combining such an optical semiconductor and a phosphor layer, it is conceivable to increase the excitation light intensity from the optical semiconductor by supplying a large current to the optical semiconductor. Heat is generated in the phosphor layer, and in the phosphor layer, the fluorescence intensity decreases due to discoloration of the resin component or temperature quenching of the phosphor. Therefore, as a result, the emission intensity is saturated and decreased, and it is difficult to increase the luminance of the light source device that combines the optical semiconductor and the phosphor layer.

  Here, the discoloration of the resin component in the phosphor layer means that the phosphor layer is usually formed into a fixed shape with good reproducibility. This is a phenomenon in which the resin component is discolored when the resin component is heated to about 200 ° C. or higher. Since the resin component is inherently transparent, if the resin component is discolored by heat, it absorbs a part of the excitation light from the optical semiconductor and the fluorescence from the phosphor layer, which prevents high brightness. It was.

  The temperature quenching of the phosphor is a phenomenon in which the fluorescence intensity decreases when the phosphor is heated. If the fluorescence intensity decreases due to temperature quenching, the energy that has not been converted to fluorescence becomes heat, so the amount of heat generated by the phosphor increases, the temperature of the phosphor rises, temperature quenching proceeds, and the fluorescence intensity further decreases. This happens. For this reason, temperature quenching of the phosphors generated by heat has also been a factor that hinders high brightness.

  In order to solve these problems, Patent Document 1 proposes a light source device using a phosphor layer that does not contain a resin. In this case, since the phosphor layer does not contain a resin component, discoloration does not occur, and furthermore, temperature quenching does not occur because the phosphor layer is a ceramic layer of a phosphor with low temperature sensitivity, so that high brightness can be achieved. is there. In addition, as shown in FIG. 1, the phosphor layer 92 is directly bonded to the optical semiconductor 95 to dissipate heat generated in the phosphor layer 92 to the optical semiconductor (solid light source) 95 side.

JP 2006-005367 A

  By the way, in the conventional light source device in which the optical semiconductor 95 and the phosphor layer 92 are directly joined as shown in FIG. 1, the heat of the phosphor layer 92 is intended to be dissipated to the optical semiconductor 95 side. When the excitation light intensity of the optical semiconductor 95 is increased, heat is generated not only in the phosphor layer 92 but also in the optical semiconductor 95, so that the heat generation in the phosphor layer 92 is dissipated from the side of the optical semiconductor 95 that is also generating heat. The efficiency of heat dissipation is not good, and there is a limit to increasing the brightness.

  The inventor of the present application adopts a configuration in which the optical semiconductor and the phosphor layer are spatially separated from each other in the prior application (Japanese Patent Application No. 2009-286397) of the present application in order to achieve a sufficiently high brightness as compared with the prior art. It was.

  However, the inventors of the present application have found a phenomenon in which unevenness occurs in the emission color in the light emitting point on the phosphor layer while examining the configuration in which the optical semiconductor and the phosphor layer are arranged spatially apart. In FIG. 2A, a blue semiconductor laser is used as an optical semiconductor, a YAG phosphor ceramic, which is a yellow phosphor not containing a resin component, is used as a phosphor layer, and excitation light is incident on the surface of the phosphor layer. In the case of using a reflection system that takes out fluorescence using reflection by a reflection surface provided on the side opposite to the side surface (this surface is referred to as a phosphor layer incident surface in the present invention), An outline of the light emission point (light emission pattern) is shown. In addition, the cross-sectional area of the beam on the phosphor layer incident surface 60 of the excitation light from the blue semiconductor laser used here was considerably smaller than the area of the entire phosphor layer incident surface 60. In FIG. 2 (a), the area indicated by the symbol A is the center of the light emitting point (the portion corresponding to the cross-sectional area of the beam of the excitation light from the blue semiconductor laser on the phosphor layer incident surface 60). The region indicated by is the peripheral portion of the light emitting point. Here, the light intensity (brightness) of the beam of the excitation light from the blue semiconductor laser on the phosphor layer incident surface 60 is Lambertian, and is the strongest at the center O of the central portion A of the emission point. At the outer edge AE of the central part A of the light emitting point, the light intensity (brightness, light quantity) is about 50% of the center O of the central part A of the light emitting point, and at the outer edge BE of the peripheral part B of the light emitting point. The light intensity (brightness, light quantity) is about 10% of the center O of the part A. FIG. 2B shows the measurement results of the chromaticity of the central portion A of the light emitting point and the peripheral portion B of the light emitting point. From the result of FIG. 2B, the central portion A of the light emitting point has a sufficient amount of excitation light from the blue semiconductor laser, and is white due to a mixture of a sufficient amount of blue excitation light and yellow fluorescence. On the other hand, the peripheral portion B of the light emitting point has a small amount of excitation light from the blue semiconductor laser (that is, the amount of blue light is small) and exhibits chromaticity on the yellow side with respect to the central portion A of the light emitting point. I understand that.

  When such a light source device having color unevenness within the light emitting point (light emission pattern) is actually used in an illumination device, the illumination light also has color unevenness, which is a serious problem in practice.

  The present invention provides a light source device and an illuminating device that can achieve a sufficiently high luminance as compared with the prior art and can prevent color unevenness in a light emitting point (light emitting pattern) in a phosphor layer. The purpose is to provide.

  In order to achieve the above object, the invention described in claim 1 is excited by a solid light source that emits light of a predetermined wavelength in a wavelength region from ultraviolet light to visible light, and excitation light from the solid light source. A phosphor layer including at least one kind of phosphor that emits fluorescence having a longer wavelength than the emission wavelength of the solid-state light source, and the solid-state light source and the phosphor layer are spatially separated from each other. In the light source device, the phosphor layer is mounted on a truncated pyramid-shaped or truncated cone-shaped light-reflecting pedestal, and the light-reflecting pedestal is mounted on a light-absorbing member. The shape and cross-sectional area of the beam on the phosphor layer incident surface of the excitation light from the solid-state light source incident on the phosphor layer mounted on the reflective pedestal are the shape of the entire phosphor layer incident surface and It is characterized by being approximately equal to the area.

  Further, the invention according to claim 2 is the light source device according to claim 1, wherein the light-reflecting pedestal is such that all of the attachment portion and outer periphery of the phosphor layer are light-reflective, or The phosphor layer is attached to a light-reflective portion, and the outer periphery is covered with a light-absorbing material.

  The invention described in claim 3 is an illumination device characterized in that the light source device described in claim 1 or claim 2 is used.

  According to the first and second aspects of the invention, the solid light source that emits light of a predetermined wavelength in the wavelength region from ultraviolet light to visible light, and the solid that is excited by the excitation light from the solid light source A light source device including a phosphor layer including at least one type of phosphor that emits fluorescence having a wavelength longer than a light emission wavelength of the light source, wherein the solid light source and the phosphor layer are arranged spatially apart from each other The phosphor layer is mounted on a truncated-pyramidal or truncated-cone light reflecting pedestal, and the light reflecting pedestal is mounted on a light-absorbing member; The shape of the beam of the excitation light from the solid-state light source incident on the phosphor layer mounted on the pedestal on the phosphor layer incident surface (the surface of the phosphor layer on which the excitation light is incident) And the cross-sectional area is the shape and area of the entire phosphor layer entrance surface Since approximately equal, it is possible to achieve a sufficiently high brightness as compared with prior art, and it is possible to prevent the color unevenness in the light emitting point (light emission pattern) of the phosphor layer. In addition, since the light-reflecting pedestal is attached to the light-absorbing member, excitation light that is not incident on the phosphor layer (extruded from the phosphor layer) (for example, excitation light that is coherent light from a semiconductor laser) ) Can be absorbed by the light-absorbing member, and the excitation light that has not entered the phosphor layer (extruded from the phosphor layer) is directly projected as illumination light to prevent the danger of harming the human body. Can do.

  Further, according to the invention described in claim 3, since the illumination device is characterized in that the light source device described in claim 1 or claim 2 is used, the illumination light can also prevent color unevenness. it can.

It is a figure which shows the conventional light source device. It is a figure for demonstrating the color nonuniformity in a light emission point (light emission pattern). It is a figure which shows the example of 1 structure of the light source device of this invention. FIG. 6 is a diagram for explaining a case where the shape and the cross-sectional area of the excitation light from the solid-state light source incident on the phosphor layer on the phosphor layer incident surface are substantially equal to the shape and area of the entire phosphor layer incident surface. is there. It is a figure which shows the other structural example of the light source device of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIGS. 3A and 3B are diagrams showing a configuration example of the light source device of the present invention. 3A is a front view of the whole, and FIG. 3B is a plan view of a portion where a phosphor layer is provided. Referring to FIG. 3A, the light source device 10 is excited by a solid light source 5 that emits light having a predetermined wavelength in a wavelength region from ultraviolet light to visible light, and excitation light from the solid light source 5. And a phosphor layer 2 containing at least one kind of phosphor that emits fluorescence having a longer wavelength than the emission wavelength of the solid light source 5, and the solid light source 5 and the phosphor layer 2 are arranged spatially separated from each other. ing.

  Here, as shown in FIGS. 3A and 3B, the phosphor layer 2 includes a truncated pyramid-shaped or truncated cone-shaped light-reflecting pedestal 6 (an example of FIGS. 3A and 3B). Then, it is attached on a light reflecting pedestal 6) having a truncated quadrangular pyramid shape, and the light reflecting pedestal 6 is attached to a light absorbing member (light absorbing substrate) 9. The light-reflecting pedestal 6 may be light-reflective on the attachment portion of the phosphor layer 2 and the outer periphery of the truncated pyramid shape or truncated cone shape, or the phosphor layer 2 may be attached. The part is light-reflective, and the part other than the attachment part of the phosphor layer 2 (such as a truncated pyramid shape or an outer periphery of the truncated cone shape) is covered with a light absorbing material (for example, black paint). Also good. In any of the above cases, the light reflective pedestal 6 preferably has a function of dissipating heat generated in the phosphor layer 2, and the light reflective pedestal 6 itself has a thermal conductivity. A large material is used, and the light-reflective base 6 preferably has a solid structure.

  As described above, the light source device 10 basically has the solid light source 5 and the phosphor layer 2 arranged spatially separated in the same manner as the prior application (Japanese Patent Application No. 2009-286397) of the present application. By the reflecting surface (phosphor layer mounting surface of the light-reflecting pedestal 6) provided on the side opposite to the surface (phosphor layer incident surface) on the side where the excitation light from the solid light source 5 is incident among the surfaces of the layer 2 A method of extracting light such as fluorescence using reflection (hereinafter referred to as a reflection method) is employed. Thereby, it is possible to achieve a sufficiently high luminance as compared with the conventional case.

  By the way, in the present invention, the phosphor layer incident surface of the excitation light from the solid light source 5 incident on the phosphor layer 2 mounted on the light reflective pedestal 6 (from the solid light source 5 out of the surfaces of the phosphor layer 2). The shape and the cross-sectional area of the beam on the surface on which the excitation light is incident are substantially the same as the shape and area of the entire phosphor layer incident surface. Here, the shape and the cross-sectional area of the beam on the phosphor layer incident surface of the excitation light from the solid light source 5 incident on the phosphor layer 2 are substantially equal to the shape and area of the entire phosphor layer incident surface. For example, as shown in FIGS. 4A and 4B, the shape of the beam 17 of the excitation light from the solid light source 5 incident on the phosphor layer 2 on the phosphor layer incident surface 16 is the phosphor layer incident surface 16. The shape is almost the same as the whole shape (in the example of FIGS. 4A and 4B, the shape of the beam 17 on the phosphor layer incident surface 16 is substantially rectangular, but the corners are rounded). The cross-sectional area of the beam 17 on the phosphor layer incident surface 16 of the excitation light from the solid light source 5 incident on the phosphor layer 2 is the total area of the phosphor layer incident surface 16. It means that it is in the range of 80% to 120%. Specifically, in the example of FIGS. 4A and 4B, the width BY in the longitudinal direction Y of the beam 17 on the phosphor layer incident surface 16 of the excitation light is equal to the longitudinal direction Y of the entire phosphor layer incident surface 16. 4A, the length BX of the beam 17 in the lateral direction X of the excitation light on the phosphor layer incident surface 16 is the lateral direction of the entire phosphor layer incident surface 16 in FIG. In FIG. 4B, the length BX of the beam 17 in the lateral direction X of the excitation light on the phosphor layer incident surface 16 is equal to the lateral direction X of the entire phosphor layer incident surface 16 in FIG. It is 120% of the length PX.

  As shown in FIGS. 4A and 4B, in order to make the shape of the beam 17 on the phosphor layer incident surface 16 substantially rectangular, the emission of an optical semiconductor (such as a light emitting diode or a semiconductor laser) is performed. This can be realized by providing a collimating lens (not shown) at the mouth and shaping the shape of the light emitted from the optical semiconductor (such as a light emitting diode or a semiconductor laser) (usually a circular shape) with the collimating lens. However, it is difficult to produce a perfect rectangular beam, and usually a substantially rectangular shape such as the beam 17 shown in FIGS. The cross-sectional area of the beam 17 on the phosphor layer incident surface 16 can be adjusted by changing the distance between the exit of the optical semiconductor (such as a light emitting diode or a semiconductor laser) and the collimating lens. . The cross-sectional area of the beam 17 on the phosphor layer incident surface 16 can also be adjusted by adjusting the incident angle of the excitation light to the phosphor layer 2. For example, when the excitation light is incident on the phosphor layer 2 at an incident angle of 90 °, the beam 17 on the phosphor layer incident surface 16 is cut off when incident at an incident angle of 45 °. The area can be increased. Further, the shape and cross-sectional area of the beam 17 on the phosphor layer incident surface 16 can be adjusted by arbitrarily designing the curved surface of the collimating lens. In the present invention, it is assumed that the solid light source 5 includes not only an optical semiconductor (such as a light emitting diode or a semiconductor laser) but also an optical system such as a collimating lens. Further, the cross-sectional area of the beam 17 can be measured by arranging a beam profiler having a CCD camera instead of the phosphor layer 2 and making the beam 17 incident on the profiler.

  Thus, in the present invention, the shape and cross-sectional area of the beam on the phosphor layer incident surface of the excitation light from the solid light source incident on the phosphor layer are substantially equal to the shape and area of the entire phosphor layer incident surface. Thus, excitation light and fluorescence can be extracted from the entire surface of the phosphor layer 2 at substantially the same ratio (excitation light color (for example, blue) and fluorescence color (for example, blue) and fluorescence color (from the entire surface of the phosphor layer 2). As a result, color unevenness in the light emission points (light emission pattern) as shown in FIG. 2A can be suppressed. In other words, when, for example, a blue semiconductor laser is used as the optical semiconductor and a YAG phosphor ceramic, which is a yellow phosphor containing no resin component, is used as the phosphor layer 2, almost the entire phosphor layer 2 has a light emitting point. Since the peripheral part B of the light emitting point can be almost eliminated, almost the entire surface of the phosphor layer 2 emits white light by mixing a sufficient amount of blue excitation light and yellow fluorescence. Thus, the yellow light emission portion can be almost eliminated, and the color unevenness in the light emission point (light emission pattern) as shown in FIG. 2A can be suppressed. As described above, the present invention can be applied to the case where the excitation light color and the fluorescence color are mixed and used.

  In addition, in the above-described configuration, the light reflecting pedestal 6 having a truncated pyramid shape or a truncated cone shape can easily attach the phosphor layer 2 to the top of the truncated cone, thereby improving the product yield. In addition, the heat of the phosphor layer 2 can be radiated (heated) more efficiently. Further, the light reflecting pedestal 6 having a truncated pyramid shape or a truncated cone shape reflects the light incident through the phosphor layer 2 toward the solid light source 5 and does not enter the phosphor layer 2. Further, it also has a role of reflecting the excitation light (excitation light that is coherent light) (extruded from the phosphor layer 2) to the light absorbing member (light absorbing substrate) 9.

  Further, in the present invention, when a semiconductor laser is used for the solid light source 5, the excitation light (excitation light that is coherent light) from the solid light source 5 that is not incident on the phosphor layer 2 (that protrudes from the phosphor layer 2) is generated. It is intended to prevent it from being directly projected as illumination light and causing harm to the human body. Specifically, in a reflective light source device using a semiconductor laser as the solid light source 5, the phosphor layer 2 is often provided on a highly reflective light reflective substrate in order to increase the emission intensity. 5 is larger than the area of the phosphor layer incident surface (that is, the sectional area of the beam 17 of the excitation light from the solid light source 5 on the phosphor layer incident surface 16 is When it is in the range of 100% to 120% of the entire area of the layer incident surface 16 (for example, as shown in FIG. 4B), the light does not enter the phosphor layer 2 (extends from the phosphor layer 2). The excitation light is reflected by the light-reflective substrate, and the excitation light, which is coherent light, is projected as it is as illumination light, and there is a danger of harming the human body. Further, even if the cross-sectional area of the excitation light beam from the solid light source 5 and the area of the phosphor layer incident surface are substantially the same or smaller (that is, the phosphor layer incident surface 16 of the excitation light from the solid light source 5). Even if the cross-sectional area of the beam 17 above is in the range of 80% to 100% of the total area of the phosphor layer entrance surface 16 (for example, as shown in FIG. 4A), it is used. When the optical axis is shifted due to external vibrations, a similar phenomenon may occur. Therefore, in the present invention, the light-reflecting pedestal 6 is attached to the light-absorbing member (light-absorbing substrate) 9, and the light-absorbing member (light-absorbing substrate) 9 is substantially provided around the phosphor layer 2. Thus, the excitation light that has not entered the phosphor layer 2 (that protrudes from the phosphor layer 2) is absorbed by the light-absorbing member (light-absorbing substrate) 9 to prevent the above-described danger. ing. At this time, even if the entire outer periphery of the truncated pyramid shape or truncated cone shape of the light reflective pedestal 6 is light reflective, it did not enter the phosphor layer 2 (phosphor layer 2). The excitation light that protrudes from the outer periphery of the truncated pyramid shape or truncated cone shape of the light-reflecting pedestal 6 is reflected toward the light-absorbing member (light-absorbing substrate) 9 to form the light-absorbing member. Since it is absorbed by (light absorbing substrate) 9, there is no problem. Further, when the outer periphery of the truncated pyramid shape or the truncated cone shape is covered with a light absorbing material (for example, black paint), the excitation that did not enter the phosphor layer 2 (extruded from the phosphor layer 2) The light is absorbed by the outer periphery of the truncated pyramid shape or truncated cone shape of the light-reflecting pedestal 6, and a part of the excitation that is not absorbed by the outer periphery of the truncated cone pyramid shape or truncated cone shape of the light-reflecting pedestal 6 Since the light is absorbed by the light absorbing member (light absorbing substrate) 9, the excitation light (excitation light that is coherent light) that is not incident on the phosphor layer 2 (extruded from the phosphor layer 2) remains as it is. It is possible to more reliably prevent projection as illumination light.

  In the present invention, the phosphor layer 2 includes a phosphor that absorbs excitation light and emits fluorescence having a wavelength longer than that of the excitation light. Phosphors include organic substances, inorganic substances, and organic-inorganic composites, but it is desirable to use inorganic phosphors having excellent reliability. The phosphor layer 2 can be formed by a method in which the phosphor is dispersed in a matrix such as resin or glass, or a method that does not substantially contain a resin component made only of an inorganic substance. In order to achieve high brightness, it is preferable to use a phosphor layer that does not substantially contain a resin component for the phosphor layer 2. Here, the phosphor layer substantially free of the resin component means that the resin component normally used for forming the phosphor layer is 5 wt% or less of the phosphor layer. For realizing such a phosphor layer, a phosphor powder dispersed in glass, a glass phosphor in which a luminescent center ion is added to a glass matrix, a phosphor single crystal or a phosphor polycrystal ( Hereinafter, phosphor ceramics). The phosphor ceramic includes a polycrystalline body made of a phosphor and a ceramic having a composition different from that of the phosphor. The phosphor ceramic is a lump of phosphor that is formed by firing a material into an arbitrary shape before firing in the phosphor manufacturing process. Phosphor ceramics may use an organic substance as a binder in the molding process in the manufacturing process. However, since the organic component is burned off by providing a degreasing process after molding, the organic resin component is not included in the phosphor ceramic after firing. Only 5 wt% or less remains. Accordingly, since most of the phosphor layer substantially free of the resin component is composed of only an inorganic substance, discoloration due to heat does not occur. In addition, glass or ceramics made of only an inorganic substance generally has a higher thermal conductivity than a resin, and thus is advantageous in heat dissipation from the phosphor layer to the substrate. In particular, phosphor ceramics are preferable because they generally have higher thermal conductivity than glass and are less expensive to manufacture than single crystals.

  The light reflective pedestal 6 can be made of a metal substrate, oxide ceramics such as alumina, non-oxide ceramics such as aluminum nitride, etc., and has particularly high light reflection characteristics, heat transfer characteristics, and workability. It is desirable to use a metal substrate.

  In addition, a resin, an organic adhesive, an inorganic adhesive, a low-melting glass, a bonding portion (not shown in FIGS. 3A and 3B) between the phosphor layer 2 and the light-reflecting pedestal 6, Metal brazing can be used. In order to utilize the high reflectance of the light-reflecting pedestal 6, it is desirable that the joint has a high transparency, and it is desirable to use a resin typified by a silicone resin or an inorganic adhesive. On the other hand, since the bonding portion plays a role of dissipating heat from the phosphor layer, a conductive adhesive containing metal brazing or a metal component is desirable if importance is attached to heat transfer characteristics.

  Further, as the light absorbing member (light absorbing substrate) 9, a black member that absorbs excitation light can be used, and a resin or metal that has been subjected to black coating can be used. Further, the light absorbing member (light absorbing substrate) 9 may be configured as shown in FIG. In the example of FIG. 5, the light-absorbing member (light-absorbing substrate) 9 has a bottom portion 9 a, a side portion 9 b, and a ceiling portion 9 c and does not enter the phosphor layer 2 (phosphor layer 2). Even if the excitation light (excitation light that is coherent light) that has protruded from the bottom portion 9a cannot be completely absorbed by the bottom portion 9a, it can be reliably prevented from leaking to the outside by the side portion 9b and the ceiling portion 9c. In the example of FIG. 5, the reflector 11 is provided above the phosphor layer 2. When the reflector 11 is provided, the light utilization efficiency from the phosphor layer 2 can be increased.

  Next, the light source device of the present invention will be described in more detail.

  In the light source device of the present invention, the solid-state light source 5 can be a light emitting diode or a semiconductor laser having an emission wavelength in the range from ultraviolet light to visible light.

More specifically, the solid-state light source 5 may be, for example, a light emitting diode or semiconductor laser that emits near-ultraviolet light having an emission wavelength of about 380 nm to about 400 nm using an InGaN-based material. In this case, the phosphor of the phosphor layer 2 is excited by ultraviolet light having a wavelength of about 380 nm to about 400 nm. For example, a red phosphor is CaAlSiN ₃ : Eu ²⁺ , (Ca, Sr) AlSiN. ₃ : Eu ²⁺ , Ca ₂ Si ₅ N ₈ : Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , KSiF ₆ : Mn ⁴⁺ , KTiF ₆ : Mn ^{4+ and the} like are used as the yellow phosphor. , (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , Ca _x (Si, Al) ₁₂ (O, N) ₁₆ : Eu ^{2+ and the} like are used, and (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , Ba ₃ Si ₆ O ₁₂ N ₂ : Eu ²⁺ , (Si, Al) ₆ (O, N) ₈ : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ^{2+ and the} like are used, and blue BaMgAl ₁₀ O ₁₇ : Eu ²⁺ or the like can be used as the color phosphor.

The solid-state light source 5 may be, for example, a light emitting diode or semiconductor laser that emits blue light having a light emission wavelength of about 460 nm using a GaN-based material. In this case, as the phosphor of the phosphor layer 2, as the wavelength is excited by the blue light of about 440nm to about 470 nm, for example, the red ^{_{phosphor, CaAlSiN 3: Eu 2+, (}} Ca, Sr) AlSiN ₃ : Eu ²⁺ , Ca ₂ Si ₅ N ₈ : Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , KSiF ₆ : Mn ⁴⁺ , KTiF ₆ : Mn ^{4+ and the} like are used as the yellow phosphor. Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , Ca _x (Si, Al) ₁₂ (O, N) ₁₆ : Eu ^2+, etc. ^{_{, Lu 3 Al 5 O 12:}} Ce 3+, (Lu, Y) 3 Al 5 O 12: Ce 3+, Y 3 (Ga, Al) 5 O 12: Ce 3+, Ca 3 Sc 2 Si 3 O 12: _{^{e 3+, CaSc 2 O 4:}} Eu 2+, (Ba, Sr) 2 SiO 4: Eu 2+, Ba 3 Si 6 O 12 N 2: Eu 2+, (Si, Al) 6 (O, N) 8: Eu 2+ Etc. can be used.

As the phosphor layer 2, a phosphor in which these phosphor powders are dispersed in glass, a glass phosphor in which a luminescent center ion is added to a glass matrix, a phosphor ceramic not including a binding member such as a resin, or the like is used. Can do. As a specific example of the phosphor powder dispersed in glass, the phosphor powder having the composition listed above is contained in a glass containing components such as P ₂ O ₃ , SiO ₂ , B ₂ O ₃ , and Al ₂ O _3. Are dispersed. Examples of glass phosphors in which a luminescent center ion is added to a glass matrix include Ca—Si—Al—O—N and Y—Si—Al—O—N systems in which Ce ³⁺ or Eu ²⁺ is added as an activator. Examples thereof include oxynitride glass phosphors. Examples of the phosphor ceramic include a sintered body having a phosphor composition having the composition listed above and substantially not including a resin component. Among these, it is desirable to use a phosphor ceramic having translucency. This is a phosphor ceramic that has translucency because there are almost no pores or impurities at grain boundaries that cause light scattering in the sintered body. Since pores and impurities can also prevent thermal diffusion, translucent ceramics exhibit high thermal conductivity. For this reason, when it uses as a fluorescent substance layer, it can take out from a fluorescent substance layer, and can utilize it, without losing excitation light and fluorescence by diffusion, Furthermore, the heat | fever which generate | occur | produced in the fluorescent substance layer can be dissipated efficiently. Even a sintered body that does not show translucency is desirable to have as few pores and impurities as possible. As an index for evaluating the remaining amount of pores, the value of specific gravity of the phosphor ceramic can be used, and it is desirable that the value is 95% or more with respect to the theoretical value by which the value is calculated.

Here, a method for producing a phosphor ceramic having translucency will be described by taking as an example a Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor that is a yellow-excited phosphor emitting blue light. The phosphor ceramic is manufactured through a starting material mixing step, a forming step, a firing step, and a processing step. As starting materials, yttrium oxide, cerium oxide, alumina, and the like, oxides of constituent elements of Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor, carbonates, nitrates, sulfates and the like that become oxides after firing are used. The particle size of the starting material is preferably a submicron size. These raw materials are weighed so as to have a stoichiometric ratio. At this time, for the purpose of improving the transmittance of the ceramic after firing, it is also possible to add a compound such as calcium or silicon. The weighed raw materials are sufficiently dispersed and mixed by a wet ball mill using water or an organic solvent. Next, the mixture is formed into a predetermined shape. As the molding method, a uniaxial pressing method, a cold isostatic pressing method, a slip casting method, an injection molding method, or the like can be used. The obtained molded body is fired at 1600 to 1800 ° C. Thus, translucent ^{_{Y 3 Al 5 O 12: Ce}} 3+ phosphor ceramic can be obtained.

  The phosphor ceramic produced as described above is polished to a thickness of several tens to several hundreds of μm using an automatic polishing apparatus and the like, and is further rounded by dicing or scribing using a diamond cutter or laser. Cut out to a board of any shape such as a square, fan or ring.

  Here, phosphor ceramics have a high refractive index with respect to air, and there are few things that cause scattering such as pores inside, and light is guided inside the ceramics. The light emission component emitted from the side surface increases, and the light emission component emitted in the front direction decreases. In order to solve this problem, the light emission component emitted in the front direction can be increased by providing an uneven light extraction structure by etching on the ceramic surface, mounting a lens, or providing a reflective layer on the side surface. Is also possible.

  The light-reflecting pedestal 6 can be made of a metal substrate, oxide ceramics, non-oxidized ceramics, etc., but it is desirable to use a metal substrate having particularly high light reflection characteristics, heat transfer characteristics, and workability. . As the metal, simple substances such as Al, Cu, Ti, Si, Ag, Au, Ni, Mo, W, Fe, Pd, and alloys containing them can be used. Further, the surface of the light reflective pedestal 6 may be coated for the purpose of increasing reflection and preventing corrosion. The shape of the pedestal 6 is preferably a pyramid shape or a cone shape so that the excitation light does not fly in the direction of the illumination light no matter which direction the excitation light protrudes from the phosphor layer 2. Moreover, since these shapes are flared from the top of the pedestal 6 to which the phosphor layer 2 is attached (the top of the top of the wharf) to the bottom of the pedestal 6, the heat from the phosphor layer 2 is also dissipated. Ideal shape.

  Moreover, resin, an organic adhesive agent, an inorganic adhesive agent, low melting glass, brazing etc. can be used for joining to the fluorescent substance layer 2 and the base 6. FIG. In particular, in order to utilize the reflectance of the light reflective substrate, it is desirable to use a resin or an inorganic adhesive having a high excitation light transmittance. These are obtained by applying a resin or an inorganic adhesive on the light-reflective top of the pedestal 6 (light-reflective wharf top), placing the phosphor layer 2 thereon, and heating in a curing furnace. Can be glued. Brazing is desirable when it is desired to improve heat dissipation. The ceramic and metal can be joined by first forming a metal film on the ceramic side and brazing the metal film and the metal substrate. The metal film can be formed on the ceramic by a vacuum deposition method, a sputtering method, a refractory metal method, or the like. The refractory metal method is a method in which an organic binder containing metal fine particles is applied to the surface of a ceramic and heated to 1000 to 1700 ° C. in a reducing atmosphere containing water vapor and hydrogen. For the metal film formed at this time, a simple substance or an alloy containing Si, Nb, Ti, Zr, Mo, Ni, Mn, W, Fe, Pt, Al, Au, Pd, Ta, Cu, or the like is used. As the brazing material, a brazing material containing Ag, Cu, Zn, Ni, Sn, Ti, Mn, In, Bi, or the like can be used. If necessary, the oxide film on the joining surface of the metal film and the metal can be removed by flux, a brazing material is placed on the joining surface, heated to 200 to 800 ° C., and cooled to be joined. Moreover, in order to prevent destruction of the joint surface due to the difference in the thermal expansion coefficient between the ceramic and the metal after joining, the joining may be performed by interposing a substance having an intermediate thermal expansion coefficient between the ceramic and the metal.

  Further, the light absorbing member (light absorbing substrate) 9 can be made of black-coated metal, ceramics, black resin, or the like. In particular, it is desirable to use a metal member having excellent workability. The light-absorbing member (light-absorbing substrate) 9 is disposed at the lower part (bottom) of the light-reflecting pedestal 6 in order to attach the light-reflecting pedestal 6 as shown in FIGS. 3 (a) and 3 (b). As shown in FIG. 5, in addition to the bottom portion 9 a, the side portion 9 b and the ceiling portion 9 c that surround the light reflective pedestal 6 may be arranged.

  In addition, resin, an organic adhesive agent, an inorganic adhesive agent, low melting glass, brazing etc. can be used for joining of the light-reflecting base 6 and the light-absorbing member (light-absorbing substrate) 9. In addition, the light reflective pedestal 6 and the light absorbing member (light absorbing substrate) 9 are integrally formed of the same material, and for example, only the light reflective pedestal 6 is subjected to a reflective surface treatment to obtain a light absorbing member (light absorbing member). Absorbent surface treatment such as black coating may be applied to the absorbent substrate 9.

  Further, by combining the above-described light source device of the present invention with a predetermined lens system, a mirror, a reflector, or the like (in combination with the reflector 11 in the example of FIG. 5), sufficiently high brightness can be obtained compared to the conventional case. It is possible to provide an illuminating device in which the illumination light has almost no color unevenness.

  The present invention can be used for automotive lighting such as headlamps, projectors, and general lighting.

2 Phosphor layer 5 Solid light source 6 Light reflective base 9 Light absorbing member (light absorbing substrate)
10 Light source device

Claims (3)

A solid-state light source that emits light of a predetermined wavelength in a wavelength region from ultraviolet light to visible light, and at least emits fluorescence having a wavelength longer than the emission wavelength of the solid-state light source when excited by excitation light from the solid-state light source A phosphor layer including one type of phosphor, wherein the solid-state light source and the phosphor layer are spatially separated from each other, and the phosphor layer has a truncated pyramid shape Or it is attached on the light-reflecting pedestal having a truncated cone shape, and the light-reflecting pedestal is attached to a light-absorbing member and is incident on the phosphor layer attached on the light-reflecting pedestal. The light source device, wherein a shape and a cross-sectional area of a beam of excitation light from the solid-state light source on a phosphor layer incident surface are substantially equal to a shape and an area of the entire phosphor layer incident surface. 2. The light source device according to claim 1, wherein the light-reflecting pedestal is light-reflective at all of the attachment portion and outer periphery of the phosphor layer, or the attachment portion of the phosphor layer is light-reflective. A light source device characterized in that the outer periphery is covered with a light-absorbing material. An illumination device using the light source device according to claim 1.

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