JP5709463B2 - Light source device and lighting device - Google Patents

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. FIG. 2A shows a light emitting point (light emission) in a phosphor layer when a blue semiconductor laser is used as an optical semiconductor and a YAG phosphor ceramic, which is a yellow phosphor containing no resin component, is used as a phosphor layer. An outline of the pattern) is shown. The cross-sectional area of the beam on the phosphor layer incident surface (surface on the side of the phosphor layer on which the excitation light is incident) 60 of the excitation light from the blue semiconductor laser used here is the phosphor layer incident It was much smaller than the area of the entire 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 phosphor that emits fluorescence having a wavelength longer than the emission wavelength of the solid-state light source, and the solid-state light source and the phosphor layer are arranged spatially separated from each other The shape and area of the beam on the phosphor layer incident surface of the excitation light from the solid light source incident on the phosphor layer is the shape and area of the entire phosphor layer incident surface. It is characterized by being almost equal to.

  Further, the invention according to claim 2 is the light source device according to claim 1, wherein when the excitation light from the solid light source is incident on the periphery of the phosphor layer, absorption means for absorbing the excitation light, or A diffusing means for diffusing the excitation light is provided.

  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 phosphor layer including at least one kind of phosphor that emits fluorescence having a wavelength longer than the emission wavelength of the light source, and the solid-state light source and the phosphor layer are arranged spatially separated from each other In the light source device, the shape of the beam on the phosphor layer incident surface of the solid state light source incident on the phosphor layer (the surface on the side of the phosphor layer on which the excitation light is incident) and Since the cross-sectional area is substantially equal to the shape and area of the entire incident surface of the phosphor layer, it is possible to achieve a sufficiently high luminance as compared with the conventional case, and the light emitting point (light emitting pattern) in the phosphor layer. Color unevenness inside can be prevented.

  In particular, according to the invention described in claim 2, in the light source device according to claim 1, when the excitation light from the solid-state light source is incident on the periphery of the phosphor layer, absorption means for absorbing the excitation light, Alternatively, since a diffusing means for diffusing the excitation light is provided, it absorbs the excitation light that has not entered the phosphor layer (extruded from the phosphor layer) (for example, excitation light that is coherent light from a semiconductor laser). It can be absorbed by the means, or can be diffused by the diffusing means, and the excitation light that has not entered the phosphor layer (extruded from the phosphor layer) is directly projected as illumination light, causing harm to the human body. Risk can be prevented.

  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. It is a figure which shows the other structural example of the light source device of this invention. It is a figure which shows the other structural example of the light source device of this invention. It is a figure which shows the other structural example of the light source device of this invention. It is a figure which shows the other structural example of the light source device of this invention. It is a figure which shows the other structural example of the light source device of this invention. It is a figure which shows the other structural example of the light source device of this invention. 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. The phosphor layer 2 containing at least one kind of phosphor that emits fluorescence having a wavelength longer than the emission wavelength of the solid-state light source 5 and the surface of the phosphor layer 2 opposite to the surface on which excitation light is incident A light-transmitting substrate 6 provided on the side surface is provided, and the solid light source 5 and the phosphor layer 2 are spatially separated from each other.

  Here, as shown in FIGS. 3A and 3B, the phosphor layer 2 is attached to the light-transmitting substrate 6 by a joint portion 7.

  Thus, this light source device 10 arranges the solid light source 5 and the phosphor layer 2 spatially apart from each other, and the surface of the phosphor layer 2 on the side on which the excitation light from the solid light source 5 is incident ( In the present invention, this surface is referred to as a phosphor layer incident surface), a method of taking out light such as fluorescence by transmitting light such as fluorescence through a light-transmitting substrate 6 provided on the surface opposite to the surface, or Excitation light is incident without providing the light-transmitting substrate 6 (in the following example, the light-transmitting substrate 6 is provided, but the light-transmitting substrate 6 is not necessarily provided in the present invention). A method of directly taking out light such as fluorescence from the side opposite to the side surface (hereinafter referred to as a transmissive method or a transmissive type) is employed, and the solid light source 5 and the phosphor layer 2 are separated spatially. It is possible to achieve sufficiently high brightness compared to the conventional That. More precisely, the transmission type or transmission type light source device emits light from the phosphor layer 2 when the phosphor layer 2 is irradiated with excitation light from the solid light source 5 as shown in FIG. This is a light source device that uses a component that emerges on the side opposite to the solid light source 5 among the fluorescent components to be emitted. At this time, the transmitted component of the excitation light is also used, and it can be used as illumination light together with the fluorescent component. good.

  By the way, in the present invention, the phosphor layer incident surface of excitation light from the solid light source 5 incident on the phosphor layer 2 attached to the light transmissive substrate 6 (from the solid light source 5 out of the surfaces of the phosphor layer 2). The shape and cross-sectional area of the beam on the surface on the side where the excitation light is incident are set to be substantially equal to 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. Although not shown, 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 same as the length PX in the lateral direction X of the entire phosphor layer incident surface 16. May be.

  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 is the phosphor layer when the phosphor layer 2 is irradiated with the beam 17 of excitation light from an optical semiconductor (such as a light emitting diode or a semiconductor laser). The area of the beam 17 on the incident surface 16 is referred to. The cross-sectional area of the beam 17 on the phosphor layer incident surface 16 changes the distance between the exit of an optical semiconductor (such as a light emitting diode or a semiconductor laser) and the collimating lens. By adjusting, it is possible to adjust. 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. Thereby, for example, even if the shape of the phosphor layer 2 is other than a rectangular shape, the shape of the beam 17 can be arbitrarily adjusted, so that irradiation light having the same shape as the phosphor layer 2 is realized. It becomes possible to do. 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.

  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 transmissive light source device using a semiconductor laser as the solid light source 5, the phosphor layer 2 is provided on the light transmissive substrate 6 having a high transmittance in order to increase the emission intensity. When the beam cross-sectional area of the excitation light is larger than the area of the phosphor layer incident surface (that is, 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 is When the area is in the range of 100% to 120% of the entire area of the surface 16 (for example, as shown in FIG. 4B), the light does not enter the phosphor layer 2 (extrudes from the phosphor layer 2). The excitation light passes through the light-transmitting substrate 6, and the excitation light, which is coherent light, is projected as illumination light as it is, and there is a risk 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. If the optical axis is shifted due to external vibrations, a similar phenomenon may occur.

  Therefore, in the light source device 10 shown in FIGS. 3A and 3B, the absorbing means 9 that absorbs the excitation light when the excitation light from the solid light source 5 is incident is provided around the phosphor layer 2. 3A and 3B, the absorbing means 9 is an absorbing member (for example, a black member) provided on the light-transmitting substrate 6 so as to surround the phosphor layer 2.

  In this way, by providing the absorbing means 9 around the phosphor layer 2, the excitation light that has not entered the phosphor layer 2 (extruded from the phosphor layer 2) is absorbed by the absorbing means 9, and is as described above. Danger can be prevented.

  The absorbing means 9 is not limited to the configuration shown in FIGS. 3A and 3B, and various modifications can be made. For example, the absorbing means 9 can be as shown in FIGS. 5 (a), 5 (b), 6 (a), 6 (b). That is, in the example of FIGS. 5A and 5B, the absorbing means 9 is configured as an absorbing material (for example, a black material) provided in the concave portion of the light-transmitting substrate 6 around the phosphor layer 2. 6 (a) and 6 (b), the absorbing means 9 is an absorbing member (for example, an enclosing member that surrounds the phosphor layer 2 on the light-transmitting substrate 6 and covers a part of the upper surface of the phosphor layer 2). Black member).

  Further, in each of the above-described examples, the excitation light that is coherent light is projected as illumination light and prevents the danger of harming the human body. However, when the excitation light from the solid light source 5 is incident, the excitation light is absorbed. The absorbing means 9 is provided around the phosphor layer 2. Instead of the absorbing means 9, a diffusion means for diffusing the excitation light when the excitation light from the solid light source 5 is incident is provided around the phosphor layer 2. It can also be provided.

  FIGS. 7A and 7B are views showing a light source device 20 in which a diffusing unit 19 is provided instead of the absorbing unit 9 in the configuration of FIGS. 3A and 3B. That is, in the light source device 20 of FIGS. 7A and 7B, the diffusing means 19 that diffuses the excitation light when the excitation light from the solid light source 5 is incident is provided around the phosphor layer 2. 7A and 7B, the diffusing unit 19 is a diffusing member (for example, a white member) provided on the light-transmitting substrate 6 so as to surround the phosphor layer 2.

  As described above, by providing the diffusing unit 19 around the phosphor layer 2, the diffusing unit 19 diffuses the excitation light that has not entered the phosphor layer 2 (extruded from the phosphor layer 2), as described above. Danger can be prevented.

  The diffusing means 19 is not limited to the configuration shown in FIGS. 7A and 7B, and various modifications can be made. For example, the diffusing means 19 can be as shown in FIGS. 8A, 8B, 9A, 9B, 10A, 10B. That is, in the example of FIGS. 8A and 8B, the diffusing unit 19 is configured as a diffusing material (for example, a white material) provided in the concave portion of the light-transmitting substrate 6 around the phosphor layer 2. 9 (a) and 9 (b), the diffusing means 19 is a diffusing member (for example, a part of the phosphor layer 2 that surrounds the phosphor layer 2 and covers a part of the upper surface of the phosphor layer 2). In the example of FIGS. 10A and 10B, the diffusing means 19 is configured as a diffusive microstructure (diffusion surface) provided on the surface of the light transmissive substrate 6. .

  As described above, by providing the absorbing means 9 or the diffusing means 19 around the phosphor layer 2, excitation light from the solid light source 5 that has not entered the phosphor layer 2 (extruded from the phosphor layer 2) ( Excitation light that is coherent light) is projected as illumination light and can be prevented from harming the human body.

  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.

  Further, it is desirable to use a light transmissive substrate 6 having a transmittance with respect to excitation light of 85% or more, particularly 90% or more. The light-transmitting substrate 6 also serves to dissipate the heat dissipated from the phosphor layer 2 to the outside and to serve as a support substrate for the phosphor layer 2. For this reason, high light transmission characteristics and heat transfer characteristics are required. The light transmissive substrate 6 may be made of plastic, glass, translucent ceramic made of single crystal or polycrystal, etc., but particularly single crystal translucent such as sapphire having both light transmissive characteristics and heat transfer characteristics. It is desirable to use a ceramic.

  In addition, a resin, an organic adhesive, an inorganic adhesive, a low-melting glass, or the like can be used for the bonding portion 7 between the phosphor layer 2 and the light transmissive substrate 6. In order to utilize the transmittance of the light-transmitting substrate 6, it is desirable that the joint portion has high transparency, and it is desirable to use a resin typified by a silicone resin or an inorganic adhesive.

  The absorbing means 9 may be anything that can absorb excitation light, such as black resin, or a colored filter member that absorbs at least excitation light (a filter in which a dye that absorbs at least excitation light is mixed in plastic), or the like. Can be used. Here, the black resin is obtained by dispersing black powder in a transparent resin. As the transparent resin, a silicone resin, an epoxy resin, a silicon epoxy resin, or the like can be used. As the black powder, metal powder, ceramic black pigments, organic black pigments, and the like can be used. First, a resin and black powder are kneaded, placed around or on the phosphor layer 2 on the light-transmitting substrate 6 by using a method such as printing or dispensing, and cured as it is in a curing furnace. In this way, a configuration as shown in FIGS. 3A and 3B can be realized. If a concave portion is provided in the light-transmitting substrate 6 first, the configuration as shown in FIGS. 5A and 5B can be realized by the same method. Furthermore, a configuration as shown in FIGS. 6A and 6B covering a part of the upper surface of the phosphor layer 2 can be realized. In addition, when a filter in which a dye that absorbs at least excitation light is mixed in plastic is used as the absorption means 9, for example, when blue light is used as the excitation light, a yellow filter can be used as the absorption means 9.

  Further, the diffusing means 19 may be any means that can diffuse the excitation light, and there are two cases, that is, when an additional member such as a white resin is used and when a diffusible fine structure is provided on the surface of the light transmissive substrate 6. Can be broadly divided. When using an additional member such as a white resin, it is further divided into a method of dispersing a white powder in a transparent resin and a case of using a white plate-like ceramic not containing a resin component. In the case of a method of dispersing white powder in a transparent resin, a silicone resin or the like can be used as the transparent resin. Further, as the white powder, ceramic powder such as aluminum oxide, zirconium oxide, and magnesium oxide can be used. In the production method, first, a resin and white powder are kneaded, arranged around the phosphor layer 2 on the light-transmitting substrate 6 using a method such as printing or dispensing, and cured as it is in a curing furnace. In this way, a configuration as shown in FIGS. 7A and 7B can be realized. If a concave portion is provided in the light-transmitting substrate 6 first, the configuration shown in FIGS. 8A and 8B can be realized by the same method. Furthermore, a configuration as shown in FIGS. 9A and 9B covering a part of the upper surface of the phosphor layer 2 can be realized. Moreover, when using the white plate-shaped ceramics which do not contain a resin component for the spreading | diffusion means 19, white plate-shaped ceramics can be produced in the procedure similar to fluorescent substance ceramics. The difference from phosphor ceramics is that no luminescent center ions are included in the material and that the pores are left to be baked in order to have diffusibility. The finished plate-like ceramic may be finished into an arbitrary shape by cutting and polishing, and may be attached to the light-transmitting substrate 6 using a resin or an adhesive. Further, when the diffusing unit 19 is configured by providing a diffusive fine structure on the surface of the light transmissive substrate 6, the fine structure provided on the light transmissive substrate 6 only needs to be able to diffuse excitation light, and the shape and the like are particularly limited. Not. For example, the fine structure provided on the light-transmitting substrate 6 may be provided as a precise periodic structure by etching, or may be provided by polishing using abrasive grains. In any case, as the diffusing means 19, a diffusible fine structure can be provided on the surface of the light-transmitting substrate 6 as shown in FIGS. 10 (a) and 10 (b).

  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, the phosphor of the phosphor layer 2 is excited by blue light having a wavelength of about 440 nm to about 470 nm. For example, the red phosphor includes 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 of manufacturing a phosphor ceramic having translucency will be described by taking as an example a Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor which is a blue-excited yellow light-emitting phosphor. 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-transmitting substrate 6 can be made of light-transmitting ceramics made of plastic, glass, single crystal or polycrystal, and in particular, light-transmitting ceramics having both light transmission characteristics and heat transfer characteristics are used. It is desirable to do. The translucent ceramics include aluminum oxide, YAG, yttrium oxide, magnesium oxide, and the like, and each includes a single crystal and a polycrystalline. Among these, it is desirable to use single crystal aluminum oxide (sapphire) that has both high transmittance and high thermal conductivity.

  In addition, a resin, an organic adhesive, an inorganic adhesive, a low-melting glass, or the like can be used for the joint 7 between the phosphor layer 2 and the light-transmitting substrate 6. Among these, in order to make use of the transmittance of the light transmissive substrate 6, it is desirable to use a resin or an inorganic adhesive having a high transmittance for excitation light. When using these, it can adhere | attach by apply | coating resin or an inorganic adhesive agent on the transparent substrate 6, arrange | positioning the fluorescent substance layer 2 on it, and heating in a curing furnace.

  Further, in the transmissive light source device of each configuration example described above, light such as fluorescence is efficiently extracted (extraction of light such as fluorescence) to the surface of the light transmissive substrate 6 opposite to the solid light source 5. An antireflection film made of a multilayer film (for increasing the amount) may be provided. Further, in order to extract the light emitting component guided through the light transmissive substrate 6, a reflective layer may be provided around the absorbing means 9 or the diffusing means 19 on the surface of the light transmissive substrate 6 on the solid light source 5 side. . FIG. 11 shows an example in which an antireflection film 31 and a reflection layer 32 are provided on the light transmissive substrate 6 in the light source device of FIG. FIG. 12 shows an example in which the light transmissive substrate 6 is provided with an antireflection film 31 and a reflection layer 32 in the light source device of FIG. Thus, by providing the light-transmissive substrate 6 with the antireflection film 31 and / or the reflective layer 32, light such as fluorescence can be extracted more efficiently in the transmissive light source device.

  In addition, by combining the above-described light source device of the present invention with a predetermined lens system, a mirror, a reflector, or the like, it is possible to achieve a sufficiently high brightness as compared with the prior art, and the illumination light can be colored. A lighting device with almost no unevenness can be provided.

  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-Transparent Substrate 9 Absorbing Means 19 Diffusing Means 10, 20 Light Source Device 31 Antireflection Film 32 Reflective Layer

Claims (3)

A solid-state light source that emits light of a predetermined wavelength in a wavelength region from ultraviolet light to visible light;
A phosphor layer including at least one type of phosphor that is excited by excitation light from the solid light source and emits fluorescence having a longer wavelength than the emission wavelength of the solid light source, and the solid light source and the phosphor layer include A transmissive light source device arranged spatially apart,
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 that is incident on the phosphor layer is substantially rather equal to the shape and area of the entire phosphor layer incident surface,
Around the phosphor layer, there is provided an absorption means for absorbing the excitation light when the excitation light from the solid light source is incident, or a diffusion means for diffusing the excitation light,
The absorbing means is composed of at least one of a black resin or a filter member containing a dye that absorbs excitation light,
The diffusion means is composed of at least one of a white resin, a pore-containing white ceramic, or a diffusive microstructure.
The light source device, wherein the absorbing means or the diffusing means is arranged in non-contact with the phosphor . The light source device according to claim 1, wherein the phosphor layer is attached on a light transmissive substrate,
The light source device, wherein the absorbing means or the diffusing means is formed in a recess formed in the light transmissive substrate . The light source device according to claim 1 or 2 , wherein the phosphor layer is attached on a light-transmitting substrate.
The absorbing means or the diffusing means is formed on a surface of the light transmissive substrate on the solid light source side,
On the surface of the light transmissive substrate on the solid light source side, a reflection layer is formed around the absorbing means or the diffusing means,
A light source device, wherein an antireflection film is formed on a surface of the light transmissive substrate opposite to the solid light source .

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