JP2013168602A - Light source device and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce color unevenness occurring in the light extraction surface of a phosphor layer while minimizing decrease in light extraction efficiency, in a light source device including a solid light source which emits light by using the light of a predetermined wavelength in the wavelength range of visible light as the excitation light, and a phosphor layer which is excited by the excitation light from the solid light source and emits fluorescent light having a wavelength longer than the emission wavelength of the solid light source.SOLUTION: A phosphor layer 2 is composed of a plurality of types of phosphor having different activator concentrations so that the emission intensity of fluorescent light is weakened from the central portion of irradiation of the excitation light from a solid light source 5 (irradiation spot portion) ST toward the periphery.

Description

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

  Conventionally, for example, in Patent Document 1 and Patent Document 2, as shown in FIG. 1, a blue LED 103 that emits blue light as excitation light, and a yellow phosphor that emits yellow light fluorescence when excited by excitation light from the blue LED 103. And a light source device that is intended to generate white light by mixing colors of excitation light (yellow light) excited by excitation light and excitation light (blue light) transmitted through the yellow phosphor layer 104. ing. In FIG. 1, reference numeral 107 denotes outgoing light (excitation light (blue light), fluorescence (yellow light)) extracted from the light extraction surface 104a of the yellow phosphor layer 104.

JP-A-5-152609 JP-A-7-99345

  By the way, in the configuration of FIG. 1, the blue light from the blue LED 103 is not all aligned in the optical axis direction X and incident on the yellow phosphor layer 104, but has an angular distribution with respect to the optical axis direction X (for example, It enters the yellow phosphor layer 104 with a Lambertian distribution. Therefore, in this case, as shown in FIG. 2, the blue light incident on the yellow phosphor layer 104 has an optical axis longer than the optical path length L1 in the yellow phosphor layer 104 of the blue light incident in the optical axis direction X. The optical path length L2 in the yellow phosphor layer 104 of blue light incident at an angle with respect to the direction X is longer in the optical path length of blue light in the yellow phosphor layer 104. Thus, blue light having an optical path length L2 incident at an angle with respect to the optical axis direction X passes through the yellow phosphor layer 104 longer than blue light having an optical path length L1 incident in the optical axis direction X. Thus, a lot of fluorescence (yellow light) is excited. As a result, as shown in FIG. 3, when viewed from the light extraction surface 104 a of the yellow phosphor layer 104, the central portion C where the blue LED 103 is disposed is bluish white, while the outer peripheral portion R is a ring. The color becomes yellowish white, and color unevenness called a yellow ring occurs.

  The above example is a case where the solid light source (light emitting element) is a blue LED, but when the solid light source is a blue LD (semiconductor laser), as shown in FIG. The light is incident on the yellow phosphor layer 104 in the optical axis direction X, and a part of the light passes through the yellow phosphor layer 104 in the optical axis direction X (the optical path length is L1). The inside of the phosphor layer 104 is guided, and the optical path length is longer than that of L1. As described above, the blue light that is guided through the yellow phosphor layer 104 by reflection, diffusion, or the like is more yellow-colored than the blue light having the optical path length L1 that passes through the yellow phosphor layer 104 substantially in the optical axis direction X. By passing through the layer 104 for a long time, a lot of fluorescence (yellow light) is excited. As a result, even when the solid-state light source is the blue LD 203, the central portion where the blue LD 203 is disposed is a bluish white when viewed from the light extraction surface 104a of the yellow phosphor layer 104, as shown in FIG. On the other hand, the outer peripheral portion becomes yellowish white in a ring shape, and color unevenness called a yellow ring occurs.

  As described above, regardless of whether the solid light source is the blue LED 103 or the blue LD 203, color unevenness called a yellow ring occurs. In the above example, the phosphor layer 104 is a yellow phosphor layer. In this case, when viewed from the light extraction surface 104a of the phosphor layer 104, the outer peripheral portion has a ring-like yellowish white color. However, similar color unevenness occurs when the phosphor layer 104 is a green phosphor layer or a red phosphor layer. That is, when the phosphor layer 104 is a green phosphor layer or a red phosphor layer, the outer peripheral portion has a ring-like greenish white and redish white.

  In the above-described example, the solid light source is a blue LED or blue LD. However, not only blue light but also a solid light source that emits visible light causes the same color unevenness as described above.

  In the above-described example, the solid light source and the phosphor layer 104 are arranged in contact with each other, but the same applies to the case where the solid light source and the phosphor layer 104 are arranged spatially apart from each other. In this principle, the same color unevenness as described above occurs.

  Such color unevenness seen when the light extraction surface 104a of the phosphor layer 104 is directly viewed is not only undesirable in terms of quality, but also color unevenness on the display surface when the light source device is used for a display device, light When used in precision equipment such as sensors, errors will also occur.

  Therefore, as shown in FIGS. 5A and 5B, a portion where the color unevenness of the light extraction surface 104a of the phosphor layer 104 (the outer peripheral portion R shown in FIG. 3) is covered with the light shielding film 105, and the color unevenness is covered. A method of concealing is also conceivable. 5A is a schematic cross-sectional view, and FIG. 5B is a plan view (viewed from the light extraction surface of the phosphor layer). However, in this case, since the light shielding film 105 covers the light (excitation light, fluorescence), there is a problem that the extraction efficiency is lowered.

  The present invention includes a solid-state light source that emits light having a predetermined wavelength in the visible light wavelength region as excitation light, and fluorescence that is excited by excitation light from the solid-state light source and has a wavelength longer than the emission wavelength of the solid-state light source. Provided are a light source device and a lighting device capable of reducing color unevenness generated on a light extraction surface of the phosphor layer and suppressing a decrease in light extraction efficiency in a light source device including a phosphor layer that emits light The purpose is to do.

In order to achieve the above object, the invention described in claim 1 is a solid-state light source that emits light having a predetermined wavelength in a visible light wavelength region as excitation light, and is excited by excitation light from the solid-state light source. A light source device comprising a phosphor layer that emits fluorescence having a longer wavelength than the emission wavelength of a solid-state light source,
The phosphor layer is composed of a plurality of types of phosphors having different activator concentrations such that the fluorescence emission intensity decreases from the central part of the irradiation of the excitation light from the solid light source toward the periphery. Yes.

  According to a second aspect of the present invention, in the light source device according to the first aspect, the phosphor layer is activated such that the central portion of the irradiation of the excitation light from the solid state light source has a maximum fluorescence emission intensity. It consists of a phosphor with a concentration of the activator, and a phosphor with a higher activator concentration or a phosphor with a lower activator concentration as it goes from the central part to the periphery of the irradiation of the excitation light from the solid light source. It is characterized by being.

  Further, the invention according to claim 3 is the light source device according to claim 1, wherein the phosphor layer has an activator concentration at which the central portion of the irradiation of excitation light from the solid state light source has a maximum fluorescence emission intensity. It is composed of a phosphor with a higher activator concentration, and is composed of a phosphor with a higher activator concentration as it goes from the central part of the irradiation of excitation light from the solid light source toward the periphery. Yes.

  According to a fourth aspect of the present invention, in the light source device according to the first aspect, the phosphor layer has an activator concentration at which the central portion of the irradiation of excitation light from the solid state light source has a maximum fluorescence emission intensity. It is composed of a phosphor with a lower activator concentration, and is composed of a phosphor with a lower activator concentration as it goes from the central part of the irradiation of excitation light from the solid light source toward the periphery. Yes.

  The invention according to claim 5 is an illumination device characterized by using the light source device according to any one of claims 1 to 4.

  According to the first to fifth aspects of the present invention, a solid-state light source that emits light having a predetermined wavelength in the visible light wavelength region as excitation light, and the solid-state light source that is excited by the excitation light from the solid-state light source. A phosphor layer that emits fluorescence having a longer wavelength than the emission wavelength of the light source, wherein the phosphor layer emits fluorescence from the central portion of the irradiation of excitation light from the solid-state light source toward the periphery. Because it is composed of multiple types of phosphors with different activator concentrations that weaken the light emission intensity, it reduces color unevenness that occurs on the light extraction surface of the phosphor layer and suppresses the decrease in light extraction efficiency Can do.

It is a figure which shows the conventional light source device. It is a figure for demonstrating the generation | occurrence | production mechanism of yellow ring in case a solid light source is blue LED. It is a figure which shows the yellow ring (color nonuniformity) which arises in the conventional light source device. It is a figure for demonstrating the generation | occurrence | production mechanism of yellow ring in case a solid light source is blue LD. It is a figure which shows an example for preventing the yellow ring (color nonuniformity) which arises in the conventional light source device. It is a figure which shows the example of 1 structure of the light source device of this invention. It is a figure which shows the change of the emitted light intensity of the fluorescence from a fluorescent substance by the activator density | concentration of a fluorescent substance. It is a figure which shows the example which changes the activator density | concentration of a fluorescent substance layer. It is a figure which shows the example which changes the activator density | concentration of a fluorescent substance layer. It is a figure which shows an example of the illuminating 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.

  6A and 6B are diagrams showing an example of the configuration of the light source device of the present invention. 6A is a schematic sectional view, and FIG. 6B is a plan view of the phosphor layer. Referring to FIG. 6A, the light source device 10 is excited by a solid light source 5 that emits light having a predetermined wavelength in the wavelength region of visible light as excitation light, and excitation light from the solid light source 5. And a phosphor layer 2 that emits fluorescence having a longer wavelength than the emission wavelength of the solid-state light source 5.

  6A and 6B, the solid light source 5 and the phosphor layer 2 are arranged spatially separated.

  The light source device 10 in FIGS. 6A and 6B is a method for extracting light (excitation light, fluorescence) from the side opposite to the surface on which the excitation light of the phosphor layer 2 is incident (hereinafter referred to as these). Is referred to as a transmission system or transmission type), and the solid light source 5 and the phosphor layer 2 are arranged spatially separated from each other, thereby making it possible to achieve a sufficiently high luminance as compared with the conventional case. Become. More precisely, the transmissive or transmissive light source device is a phosphor when the phosphor layer 2 is irradiated with excitation light from the solid light source 5 as shown in FIGS. 6 (a) and 6 (b). Among the fluorescent components emitted from the layer 2, it is a light source device that uses a component that emerges on the opposite side of the solid light source 5. At this time, the transmitted component of the excitation light is also used, and the fluorescent component and the excitation light are used. The mixed light with the transmitted component can be taken out as outgoing light (illumination light).

  Here, a light emitting diode (LED) having a light emission wavelength in the visible light region, a semiconductor laser (LD), or the like can be used as the solid light source 5.

Specifically, for example, a light emitting diode or a semiconductor laser that emits blue light having a light emission wavelength of about 460 nm using a GaN-based material can be used as the solid light source 5. 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.

  That is, for the phosphor layer 2, a red phosphor, a yellow phosphor, a green phosphor, or a mixture thereof can be used.

Further, as the phosphor layer 2, those phosphor powders dispersed in glass, glass phosphors in which a luminescent center ion is added to a glass matrix, or these phosphor powders are made of resin (for example, silicone resin). ) Or the like dispersed in a binder, or phosphor ceramics that do not contain a binder such as a resin. 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. As the glass phosphor in which the luminescent center ion is added to the glass matrix, an acid such as Ca—Si—Al—O—N or Y—Si—Al—O—N containing Ce ³⁺ or Eu ²⁺ as an activator is used. Nitride glass phosphors may be mentioned. 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. Translucent ceramics show high thermal conductivity because there are almost no pores or impurities that cause thermal diffusion. 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.

  By the way, in the light source device 10 of FIGS. 6A and 6B, if the phosphor layer 2 is formed of the same type of phosphor (for example, one type of phosphor having the same activator concentration), As described above, color unevenness such as a yellow ring occurs on the outer peripheral portion of the light extraction surface 2a of the phosphor layer 2.

  As described above, the reason why the color unevenness occurs as described above is that the optical path length of the excitation light (for example, blue light) from the solid light source 5 in the phosphor layer 2 depends on the excitation light in the phosphor layer 2. This is because the fluorescence increases as it increases from the central part of the irradiation toward the periphery. Therefore, color unevenness such as yellow ring can be reduced by reducing the fluorescence emission intensity as it goes from the central part to the periphery of the irradiation of excitation light in the phosphor layer 2.

  The inventors of the present application focused on the fact that the fluorescence emission intensity from the phosphor changes depending on the concentration of the activator of the phosphor. FIG. 7 is a diagram showing a change in emission intensity of fluorescence from the phosphor depending on the concentration of the activator of the phosphor. Referring to FIG. 7, the emission intensity of the fluorescence from the phosphor usually increases as the activator concentration is increased, and decreases after reaching a maximum value at a certain activator concentration F0.

  The phenomenon in which the fluorescence emission intensity from the phosphor decreases after reaching a maximum value at the activator concentration F0 is called concentration quenching. In general phosphors, the activator concentration is several times that of the base crystal. When added at a mol% or higher, (1) cross relaxation due to resonance transfer occurs between activators, and a part of excitation energy is lost, and (2) excitation migration occurs due to resonance transfer between activators. , This promotes the transition and extinction of excitation to the crystal surface and non-luminescent center, (3) the activator aggregates or forms an ion pair, and changes to non-luminescent center and killer (fluorescence inhibitor), etc. It is known that concentration quenching occurs for this reason.

  As described above, the present invention has been made by paying attention to the fact that the emission intensity of fluorescence from the phosphor changes depending on the concentration of the activator of the phosphor, and the light source device shown in FIGS. 6 (a) and 6 (b). 10, the phosphor layer 2 includes a plurality of types of phosphors having different activator concentrations such that the emission intensity of fluorescence decreases from the central portion (irradiation spot portion) ST of the excitation light irradiation from the solid light source 5 toward the periphery. It consists of

  More specifically, as a first example, the phosphor layer 2 has an activator concentration such that the central portion (irradiation spot portion) ST of the irradiation of excitation light from the solid light source 5 has the maximum fluorescence emission intensity. A phosphor or an activator that is composed of a phosphor having an activator concentration F0 in FIG. 7 and that has a higher activator concentration as it goes from the central portion ST to the periphery of the irradiation of excitation light from the solid light source 5. It can be composed of a phosphor having a low concentration. In this case, the fluorescence emission intensity becomes maximum at the central portion ST of the excitation light irradiation from the solid light source 5, and the fluorescence emission intensity increases from the central portion ST of the excitation light irradiation from the solid light source 5 toward the periphery. Since it becomes weaker, even if a lot of fluorescence is excited from the central part ST of the irradiation of the excitation light toward the periphery, it can be offset and color unevenness such as yellow ring can be reduced.

  Further, as a second example, the phosphor layer 2 has an activation agent concentration (activation of FIG. 7) in which the central portion (irradiation spot portion) ST of the excitation light from the solid light source 5 has the maximum fluorescence emission intensity. Activator concentration (activator concentration F1 in FIG. 7) is higher than the concentration of the activator, and the concentration of the activator increases from the central portion ST of the irradiation of the excitation light from the solid light source 5 toward the periphery. It can be composed of a phosphor having a high value. Also in this case, the fluorescence emission intensity becomes maximum at the central portion ST of the excitation light irradiation from the solid light source 5, and the fluorescence emission intensity increases from the central portion ST of the excitation light irradiation from the solid light source 5 toward the periphery. Since it becomes weaker, even if a lot of fluorescence is excited from the central part ST of the irradiation of the excitation light toward the periphery, it can be offset and color unevenness such as yellow ring can be reduced.

  Further, as a third example, the phosphor layer 2 has an activation agent concentration (activation of FIG. 7) at which the central portion (irradiation spot portion) ST of the excitation light from the solid light source 5 has the maximum fluorescence emission intensity. Activator concentration (activator concentration F2 in FIG. 7) lower than the agent concentration F0), and the concentration of the activator increases from the central portion ST of the irradiation of the excitation light from the solid light source 5 toward the periphery. It can be composed of a phosphor that lowers. Also in this case, the fluorescence emission intensity becomes maximum at the central portion ST of the excitation light irradiation from the solid light source 5, and the fluorescence emission intensity increases from the central portion ST of the excitation light irradiation from the solid light source 5 toward the periphery. Since it becomes weaker, even if a lot of fluorescence is excited from the central part ST of the irradiation of the excitation light toward the periphery, it can be offset and color unevenness such as yellow ring can be reduced.

  In each of the above examples (for example, in the second example), the concentration of the activator in the AA line of the phosphor layer 2 in FIG. 6B is from the solid light source 5 as shown in FIG. FIG. 6B shows a stepwise change from the central portion (irradiation spot portion) ST of the excitation light irradiation to the periphery (although it becomes higher stepwise in the second example). The activator concentration in the AA line of the phosphor layer 2 can be continuously changed as shown in FIG. 8B (in the second example, it can be continuously increased). 8A and 8B, the concentration of the activator of the phosphor layer 2 is constant in the central portion (irradiation spot portion) ST of the excitation light irradiation. As in the examples of (a) and (b), the concentration of the activator of the phosphor layer 2 may be changed from within the central portion (irradiation spot portion) ST of the excitation light irradiation.

  As described above, in the present invention, the phosphor layer 2 includes a plurality of types of phosphors having different activator concentrations such that the emission intensity of fluorescence decreases from the central portion ST to the periphery of the irradiation of the excitation light from the solid light source 5. Therefore, it is possible to prevent color unevenness such as a yellow ring from occurring in the outer peripheral portion of the light extraction surface 2a of the phosphor layer 2, and also in this case, it is possible to suppress a decrease in light extraction efficiency. .

  In the configuration example described above, the solid light source 5 and the phosphor layer 2 are arranged spatially separated from each other, but the solid light source 5 and the phosphor layer 2 may be arranged in contact with each other. In addition, the phosphor layer 2 is formed of a plurality of types of phosphors having different activator concentrations such that the emission intensity of the fluorescence decreases from the central portion (irradiation spot portion) ST of the excitation light from the solid light source 5 toward the periphery. With this configuration, it is possible to prevent color unevenness such as a yellow ring from occurring in the outer peripheral portion of the light extraction surface 2a of the phosphor layer 2, and to suppress a decrease in light extraction efficiency.

  The light source device 10 can be configured as a lighting device by combining with a predetermined lens system, a mirror, a reflector, or the like. FIG. 10 is a view showing an illumination device that combines the light source device 10 and a lens system. In the illumination device of FIG. 10, the light source device 10 and a lens system 52 that irradiates light from the light source device 10 forward with a predetermined light distribution characteristic are stored in a housing 51. In this illuminating device, by using the light source device 10, it is possible to obtain illumination light that does not cause color unevenness such as yellow ring even when the lens system 52 is used.

  In addition, the light source device 10 of the above-described example, when the excitation light from the solid light source 5 is incident on the phosphor layer 2, the fluorescence from the side opposite to the surface on which the excitation light of the phosphor layer 2 is incident. However, the present invention is not limited to this, and the light source device is of a reflection type (reflection type) (that is, a phosphor). The case of a reflection method (reflection type) in which light such as fluorescence is extracted from the same side as the surface on which the excitation light of the layer 2 is incident is also included in the scope of the present invention. That is, even when the light source device is of a reflective type (reflective type), the phosphor layer 2 is placed on the central portion (irradiation spot) of the excitation light from the solid light source 5 as in the transmissive type (transmissive type). (Part) By comprising a plurality of types of phosphors having different activator concentrations so that the fluorescence emission intensity decreases from the ST toward the periphery, a yellow ring or the like is formed on the outer periphery of the light extraction surface 2a of the phosphor layer 2. Color unevenness can be prevented, and reduction in light extraction efficiency can be suppressed.

  FIGS. 11A and 11B are views (schematic cross-sectional views) showing an example of a light source device that is of a reflection type (reflection type). 11A is a schematic cross-sectional view, and FIG. 11B is a plan view of the phosphor layer. FIGS. 11A and 11B are the same as FIGS. 6A and 6B. The same code | symbol is attached | subjected to the location. In the light source device 20 of FIGS. 11A and 11B, light (fluorescence, excitation light) is provided on the side opposite to the surface on which the excitation light (excitation light from the solid light source 5) of the phosphor layer 2 is incident. ) Is reflected (light (fluorescence, excitation light) is emitted as emitted light to the solid light source 5 side). Here, as the substrate 25, it is possible to use a metal substrate itself or a substrate in which a metal film is arranged on a transparent substrate, for example.

  Even when the light source device is configured as a reflection type (reflection type) as in the light source device 20 of FIGS. 11A and 11B, the phosphor layer 2 is excited with the excitation light from the solid light source 5. Of the light extraction surface 2a of the phosphor layer 2 by comprising a plurality of types of phosphors having different activator concentrations such that the fluorescence emission intensity decreases from the central portion (irradiation spot portion) ST toward the periphery. It is possible to prevent color unevenness such as a yellow ring from occurring on the outer peripheral portion, and to suppress a decrease in light extraction efficiency.

  Moreover, the illumination device as shown in FIG. 10 can also be configured by using a light source device 20 of a reflection system (reflection type) as shown in FIGS.

  Next, examples of the present invention will be described.

In this embodiment, the reflection type (reflection type) light source device 20 as shown in FIGS. 11A and 11B is used, and a blue semiconductor laser having a peak wavelength of 445 nm is used as the solid light source 5. To do. The irradiation spot of the excitation light (blue light) from the solid light source 5 is adjusted by a collimator lens (not shown) so that the irradiation spot in the phosphor layer 2 is 0.9 mm, and the excitation light (blue light) from the solid light source 5 is fluorescent. The body layer 2 is irradiated at an incident angle of 60 °. The phosphor layer 2 emits yellow phosphor Y ₃ Al ₅ O ₁₂ : Ce ³⁺ within a range of 0.8 mm in diameter from the center where the diameter is 2.0 mm, the thickness is 200 μm, and the chromaticity x is about 0.370. Activator concentration (Ce concentration) is 1.0 mol%, and concentration quenching occurs in a region of 0.8-1.0 mm from the center where chromaticity x changes from about 0.370 to about 0.440. The activator concentration (Ce concentration) at which the emission of the yellow phosphor Y ₃ Al ₅ O ₁₂ : Ce ³⁺ is slightly weakened is set to 2.0 mol%, and the region outside it is further yellow phosphor Y ₃ Al ₅ O ₁₂ : Ce ^The activator concentration (Ce concentration) at which ³⁺ emission is weakened is 3.0 mol%. In this way, when the phosphor layer 2 is made of a yellow phosphor and blue light is emitted as the excitation light from the solid light source 5, the excitation light (blue light) and fluorescence ( In this example, the activator is such that the emission intensity of the fluorescence (yellow light) decreases from the center of the phosphor layer 2 to the periphery of the phosphor layer 2 toward the periphery. Since the density is changed (increased), yellowing can be prevented from occurring in white light as emitted light. That is, the change in chromaticity can be reduced.

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

2 phosphor layer 5 solid light source 10, 20 light source device 25 substrate having reflection surface 51 housing 52 lens system ST central portion (irradiation spot portion) of excitation light irradiation

Claims (5)

A solid-state light source that emits light having a predetermined wavelength in the wavelength region of visible light as excitation light, and a phosphor that is excited by excitation light from the solid-state light source and emits fluorescence having a longer wavelength than the emission wavelength of the solid-state light source A light source device comprising a layer,
The phosphor layer is composed of a plurality of types of phosphors having different activator concentrations such that the emission intensity of fluorescence decreases from the central part of the irradiation of excitation light from the solid-state light source toward the periphery. Light source device. 2. The light source device according to claim 1, wherein the phosphor layer is formed of a phosphor having an activator concentration such that a central portion of irradiation of excitation light from the solid light source has a maximum fluorescence emission intensity. 3. The light source device is characterized in that it is composed of a phosphor whose activator concentration increases as it goes from the central part of the irradiation of excitation light from the solid light source to the periphery, or a phosphor whose activator concentration decreases. . 2. The light source device according to claim 1, wherein the phosphor layer is a phosphor having an activator concentration higher than an activator concentration at which a central portion of excitation light irradiation from the solid light source has a maximum fluorescence emission intensity. A light source device comprising: a phosphor having a concentration of an activator that increases from a central portion of the irradiation of excitation light from the solid-state light source toward the periphery. 2. The light source device according to claim 1, wherein the phosphor layer is a phosphor having an activator concentration lower than an activator concentration at which a central portion of irradiation of excitation light from the solid light source has a maximum fluorescence emission intensity. A light source device comprising: a phosphor having a concentration of an activator that decreases from a central portion of the irradiation of excitation light from the solid light source toward the periphery. An illumination device, wherein the light source device according to any one of claims 1 to 4 is used.

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