JP2015005650A - Wavelength conversion member, light source having wavelength conversion member and vehicle headlamp having light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the luminous efficacy or adjust luminescent color.SOLUTION: A wavelength conversion member 11 includes fluorescent substances 15 and 17 that convert a beam of light from a semiconductor light emitting device 12 into a light beam of a longer wavelength. The wavelength conversion member is formed of a double layered wavelength conversion layer each layer having at least an emission spectrum different from each other. The peak wavelength of the emission spectrum of the wavelength conversion layer gets longer, the layer gets closer to the side to which the light from the semiconductor light emitting device 12 incidents.

Description

  The present invention relates to a wavelength conversion member including a phosphor that converts wavelength of light from a semiconductor light emitting element into light having a longer wavelength, a light source including the wavelength conversion member, and a vehicle headlamp including the light source.

  2. Description of the Related Art Conventionally, a lamp that generates light, a semiconductor light-emitting element that generates light, a phosphor that is provided apart from the semiconductor light-emitting element, and a first that focuses light generated by the semiconductor light-emitting element on the phosphor An optical member and a second optical member having an optical center at a position where the phosphor is provided and irradiating the outside of the lamp with light generated by the phosphor in response to the light collected by the first optical member There was a headlamp provided with (patent document 1).

JP 2005-150041 A

  However, according to the prior art, improvement in luminous efficiency or adjustment of luminous color has been demanded.

  This indication is made in view of the above-mentioned subject, and aims at improving luminous efficiency or adjusting luminous color.

  The wavelength conversion member which concerns on 1 aspect of this indication is a wavelength conversion member provided with the fluorescent substance which wavelength-converts the light from a semiconductor light-emitting device into light of longer wavelength, Comprising: The wavelength which has a different emission spectrum of at least 2 layers The peak wavelength of the emission spectrum of the wavelength conversion layer including the conversion layer is longer for the layer on the side where the light from the semiconductor light emitting element is incident.

  According to the present disclosure, the light emission efficiency can be improved or the light emission color can be adjusted.

It is a block diagram which shows schematic structure of the light source which concerns on 1st Embodiment. It is a block diagram which shows schematic structure of the light source which concerns on 2nd Embodiment. It is a block diagram which shows schematic structure of the light source which concerns on 3rd Embodiment. It is a block diagram which shows schematic structure of the light source which concerns on 4th Embodiment. It is a block diagram which shows schematic structure of the light source which concerns on 5th Embodiment. It is a block diagram which shows schematic structure of the light source which concerns on 6th Embodiment. It is a block diagram which shows schematic structure of the light source which concerns on 7th Embodiment. It is a block diagram which shows schematic structure of the vehicle headlamp which concerns on 8th Embodiment. It is a block diagram which shows schematic structure of the vehicle which concerns on 9th Embodiment.

  The wavelength conversion member according to the first aspect (aspect) of the present disclosure is a wavelength conversion member including a phosphor that converts light from a semiconductor light emitting element into light having a longer wavelength, and the wavelength conversion member includes: It includes at least two wavelength conversion layers having different emission spectra, and the peak wavelength of the emission spectrum of the wavelength conversion layer is longer for the layer on the side where light from the semiconductor light emitting element is incident.

  In the wavelength conversion member according to the second aspect of the present disclosure, in the wavelength conversion member according to the first aspect, at least one of the wavelength conversion layers does not include a resin binder.

  The wavelength conversion member according to the third aspect of the present disclosure is the wavelength conversion member according to the first or second aspect, wherein at least one of the wavelength conversion layers has a thermal conductivity of 10 W / (in addition to the phosphor particles). m · K) or more particles.

  The wavelength conversion member according to the fourth aspect of the present disclosure is the wavelength conversion member according to the third aspect, wherein the wavelength conversion member contains particles having a thermal conductivity of 10 W / (m · K) or more in the wavelength conversion layer. The layer is disposed closest to the semiconductor light emitting device.

  A light source according to a fifth aspect of the present disclosure includes the wavelength conversion member according to any one of the first to fourth aspects.

  The wavelength conversion member according to the sixth aspect of the present disclosure is a wavelength conversion member made of a phosphor that converts the light from the semiconductor light emitting element into light having a longer wavelength, and emits light depending on the position where the excitation light is irradiated. Changes continuously or stepwise.

  A wavelength conversion member according to a seventh aspect of the present disclosure includes the wavelength conversion member according to the sixth aspect, including at least two wavelength conversion layers having different emission spectra, and the ratio of the thicknesses of the different layers is continuous. Different.

  A light source according to the eighth aspect of the present disclosure includes the wavelength conversion member according to the sixth or seventh aspect of the present disclosure, and includes a semiconductor laser as a semiconductor light emitting element.

  The light source which concerns on the 9th side surface of this indication is a light source which concerns on an 8th side surface, and controls the irradiation position of the excitation light to the wavelength conversion member by a semiconductor laser using a movable mirror.

  The light source which concerns on the 10th side surface of this indication is a light source which concerns on an 8th side surface, and controls the irradiation position of the excitation light to the wavelength conversion member by a semiconductor laser by making a wavelength conversion member movable.

  A light source according to an eleventh aspect of the present disclosure controls the irradiation position of the excitation light to the wavelength conversion member by lighting control of a plurality of semiconductor lasers in the light source according to the eighth aspect.

  A vehicle headlamp according to a twelfth aspect of the present disclosure includes the light source according to any one of the eighth to eleventh aspects.

(First embodiment)
FIG. 1 shows a schematic configuration of a light source 10 according to the first embodiment of the present disclosure. The light source 10 includes a wavelength conversion member 11 and a semiconductor light emitting element 12. The semiconductor light emitting element 12 is, for example, an LED, a super luminescent diode (SLD), or a laser diode (LD). In the present embodiment, the case where the semiconductor light emitting element 12 is an LD will be described. The semiconductor light emitting element 12 may be one LD, or may be one in which a plurality of LDs are optically coupled. The semiconductor light emitting element 12 emits blue-violet light, for example. In the present disclosure, blue-violet light refers to light having a peak wavelength of 380 nm to 420 nm. An incident optical system 19 that guides the light of the semiconductor light emitting element 12 to the wavelength converting member 11 may be provided between the wavelength converting member 11 and the semiconductor light emitting element 12. The incident optical system 19 includes, for example, a lens, a mirror, and / or an optical fiber.

  The wavelength conversion member 11 converts the light from the semiconductor light emitting element 12 into light having a longer wavelength. The wavelength conversion member 11 includes at least two wavelength conversion layers having different emission spectra. The peak wavelength of the emission spectrum of the wavelength conversion layer becomes longer as the wavelength conversion layer is closer to the side on which light from the semiconductor light emitting element 12 is incident, for example. For example, among the peak wavelengths of the emission spectrum of each wavelength conversion layer, the peak wavelength of the emission spectrum of the wavelength conversion layer closest to the side on which the light from the semiconductor light emitting element 12 is incident is the longest wavelength. The peak wavelength of the emission spectrum of the wavelength conversion layer farthest from the light incident side may be the shortest wavelength.

  In the present embodiment, the case where the wavelength conversion member 11 includes a first phosphor layer 13 and a second phosphor layer 14 as wavelength conversion layers will be described. The first phosphor layer 13 includes a plurality of first phosphors 15 that emit light upon receiving light from the semiconductor light emitting element 12, and a binder 16 disposed between the plurality of first phosphors 15. . The second phosphor layer 14 includes a plurality of second phosphors 17 that emit light upon receiving light from the semiconductor light emitting element 12 via the first phosphor layer 13, and a plurality of second phosphors 17. And a binder 18 disposed therebetween. The first phosphor layer 13 is provided at a position closer to the side on which light from the semiconductor light emitting element 12 is incident than the second phosphor layer 14.

  The first phosphor 15 is, for example, a yellow phosphor. In the present disclosure, the yellow phosphor refers to a phosphor having an emission spectrum peak wavelength of 540 nm or more and 590 nm or less. The second phosphor 17 is, for example, a blue phosphor. In the present disclosure, the blue phosphor refers to a phosphor having an emission spectrum peak wavelength of 420 nm or more and 480 nm or less. The binders 16 and 18 are media, such as resin, glass, or a transparent crystal, for example. The binders 16 and 18 may be made of the same material or different materials.

  Next, the operation of the light source 10 will be described. The light emitted from the semiconductor light emitting element 12 passes through the incident optical system 19 and enters the first phosphor layer 13 of the wavelength conversion member 11. By this incident light, the plurality of first phosphors 15 of the first phosphor layer 13 are excited to emit yellow light. A part of the light from the semiconductor light emitting element 12 passes through the first phosphor layer 13 and enters the second phosphor layer 14 of the wavelength conversion member 11. By this incident light, the plurality of second phosphors 17 of the second phosphor layer 14 are excited to emit blue light. These yellow light and blue light are mixed to become white light.

  As described above, according to the first embodiment of the present disclosure, the peak wavelength of the emission spectrum of the wavelength conversion layer is, for example, closer to the wavelength conversion layer closer to the side on which the light from the semiconductor light emitting element 12 is incident. Long wavelength. Therefore, when the side opposite to the side on which the light from the semiconductor light emitting element 12 is incident is the emission side, when the wavelength conversion light from a certain wavelength conversion layer goes to the emission side, the wavelength conversion light is transmitted by another wavelength conversion layer. Absorption can be avoided. Therefore, luminous efficiency is improved. Moreover, the temperature rise of the wavelength conversion element 12 can be suppressed.

(Second Embodiment)
FIG. 2 shows a schematic configuration of the light source 20 according to the second embodiment of the present disclosure. The same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The light source 20 includes a wavelength conversion member 27 and the semiconductor light emitting element 12. Between the wavelength conversion member 27 and the semiconductor light emitting element 12, an incident optical system 19 that guides the light of the semiconductor light emitting element 12 to the wavelength conversion member 11 may be provided.

  The wavelength conversion member 27 converts the light from the semiconductor light emitting element 12 into light having a longer wavelength. The wavelength conversion member 27 includes the second phosphor layer 14, the third phosphor layer 21, and the fourth phosphor layer 22 as wavelength conversion layers. The third phosphor layer 21 includes a plurality of third phosphors 23 that emit light upon receiving light from the semiconductor light emitting element 12, and a binder 24 disposed between the plurality of third phosphors 23. . The fourth phosphor layer 22 includes a plurality of fourth phosphors 25 that emit light upon receiving light from the semiconductor light emitting element 12 via the third phosphor layer 21, and a plurality of fourth phosphors 25. And a binder 26 disposed therebetween.

  The third phosphor layer 21 is provided at a position closer to the side on which light from the semiconductor light emitting element 12 is incident than the second phosphor layer 14 and the fourth phosphor layer 22. The fourth phosphor layer 22 is provided at a position closer to the side on which the light from the semiconductor light emitting element 12 is incident than the second phosphor layer 14. The third phosphor 21 is, for example, a red phosphor. In the present disclosure, the red phosphor refers to a phosphor having an emission spectrum peak wavelength of 590 nm to 780 nm. The fourth phosphor 22 is, for example, a green phosphor. In the present disclosure, the green phosphor refers to a phosphor having an emission spectrum peak wavelength of 480 nm or more and 540 nm or less. The binders 24 and 26 are media, such as resin, glass, or a transparent crystal, for example. The binders 18, 24 and 26 may be made of the same material or different materials.

  Next, the operation of the light source 20 will be described. The light emitted from the semiconductor light emitting element 12 passes through the incident optical system 19 and enters the third phosphor layer 21 of the wavelength conversion member 27. With this incident light, the plurality of third phosphors 23 of the third phosphor layer 21 are excited to emit red light. A part of the light from the semiconductor light emitting element 12 passes through the third phosphor layer 21 and enters the fourth phosphor layer 22 of the wavelength conversion member 27. With this incident light, the plurality of fourth phosphors 25 of the fourth phosphor layer 22 are excited to emit green light. A part of the light from the semiconductor light emitting element 12 passes through the fourth phosphor layer 22 and enters the second phosphor layer 14 of the wavelength conversion member 27. By this incident light, the plurality of second phosphors 17 of the second phosphor layer 14 are excited to emit blue light. These red light, green light and blue light are mixed to become white light.

  As described above, according to the second embodiment of the present disclosure, in addition to the same effects as those of the first embodiment, since the three types of phosphors 17, 23, and 25 are further included, the broader An emission spectrum is obtained, and the effect of improving color rendering can be obtained. In addition, since red light is emitted, the visibility of the sign is improved when applied to a vehicle headlamp.

(Third embodiment)
FIG. 3 shows a schematic configuration of the light source 30 according to the third embodiment of the present disclosure. The same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The light source 30 includes a wavelength conversion member 31 and the semiconductor light emitting element 12. Between the wavelength conversion member 31 and the semiconductor light emitting element 12, an incident optical system 19 that guides the light of the semiconductor light emitting element 12 to the wavelength conversion member 11 may be provided.

  The wavelength conversion member 31 converts the light from the semiconductor light emitting element 12 into light having a longer wavelength. The wavelength conversion member 31 includes at least two wavelength conversion layers having different emission spectra. The peak wavelength of the emission spectrum of the wavelength conversion layer becomes longer as the wavelength conversion layer is closer to the side on which light from the semiconductor light emitting element 12 is incident, for example. For example, among the peak wavelengths of the emission spectrum of each wavelength conversion layer, the peak wavelength of the emission spectrum of the wavelength conversion layer closest to the side on which the light from the semiconductor light emitting element 12 is incident is the longest, and from the semiconductor light emitting element 12 The peak wavelength of the emission spectrum of the wavelength conversion layer farthest from the light incident side may be the shortest wavelength. At least one of the plurality of wavelength conversion layers does not contain, for example, a resin binder.

  In the present embodiment, the case where the wavelength conversion member 31 includes the second phosphor layer 14 and the phosphor sintered body layer 32 as wavelength conversion layers will be described. The phosphor sintered body layer 32 receives light from the semiconductor light emitting element 12 and emits light. For example, the phosphor sintered body layer 32 has a peak wavelength of an emission spectrum of 540 nm or more and 590 nm or less. The phosphor sintered body layer 32 does not contain a resin binder.

  The phosphor sintered body layer 32 is provided at a position closer to the side on which the light from the semiconductor light emitting element 12 is incident than the second phosphor layer 14. The phosphor sintered body layer 32 emits yellow light, for example. Here, the yellow light means light having a peak wavelength of 540 nm or more and 590 nm or less.

  Next, the operation of the light source 30 will be described. The light emitted from the semiconductor light emitting element 12 passes through the incident optical system 19 and enters the phosphor sintered body layer 32 of the wavelength conversion member 31. The phosphor sintered body layer 32 is excited by this incident light and emits yellow light. A part of the light from the semiconductor light emitting element 12 passes through the phosphor sintered body layer 32 and enters the second phosphor layer 14 of the wavelength conversion member 31. By this incident light, the plurality of second phosphors 17 of the second phosphor layer 14 are excited to emit blue light. These yellow light and blue light are mixed to become white light.

  In the above description, an example in which one of the plurality of wavelength conversion layers does not include the resin binder has been described. However, the plurality of wavelength conversion layers may not include the resin binder, and all the wavelength conversion layers may be included. The resin binder may not be included. For example, instead of the second phosphor layer 14, a phosphor sintered body layer that emits blue light may be provided.

  As described above, according to the third embodiment of the present disclosure, in addition to the same effects as those of the first embodiment, since the phosphor sintered body layer 32 does not contain a resin binder, it is abrupt. The effect of reducing cracks due to temperature changes can be obtained.

(Fourth embodiment)
FIG. 4 shows a schematic configuration of a light source 40 according to the fourth embodiment of the present disclosure. The same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The light source 40 includes a wavelength conversion member 41 and the semiconductor light emitting element 12. An incident optical system 19 that guides the light of the semiconductor light emitting element 12 to the wavelength converting member 11 may be provided between the wavelength converting member 41 and the semiconductor light emitting element 12.

  The wavelength conversion member 41 converts the light from the semiconductor light emitting element 12 into light having a longer wavelength. The wavelength conversion member 41 includes at least two wavelength conversion layers having different emission spectra. The peak wavelength of the emission spectrum of the wavelength conversion layer becomes longer as the wavelength conversion layer is closer to the side on which the light from the semiconductor light emitting element 12 is incident, for example. For example, among the peak wavelengths of the emission spectrum of each wavelength conversion layer, the peak wavelength of the emission spectrum of the wavelength conversion layer closest to the side on which the light from the semiconductor light emitting element 12 is incident is the longest, and from the semiconductor light emitting element 12 The peak wavelength of the emission spectrum of the wavelength conversion layer farthest from the light incident side may be the shortest wavelength. At least one of the plurality of wavelength conversion layers contains particles (high thermal conductivity particles) having a thermal conductivity of 10 W / (m · K) or more in addition to the phosphor particles. The wavelength conversion layer containing highly thermally conductive particles may be disposed closest to the semiconductor light emitting element among the plurality of wavelength conversion layers.

  The wavelength conversion member 31 includes, for example, the second phosphor layer 14 and the fifth phosphor layer 42 as the wavelength conversion layer. The fifth phosphor layer 42 includes a plurality of fifth phosphors 43 that emit light upon receiving light from the semiconductor light emitting element 12, and highly thermally conductive particles 44 disposed between the plurality of fifth phosphors 43. Have The fifth phosphor layer 42 is provided at a position closer to the side on which the light from the semiconductor light emitting element 12 is incident than the second phosphor layer 14. The fifth phosphor 43 is, for example, a yellow phosphor.

  Next, the operation of the light source 40 will be described. The light emitted from the semiconductor light emitting element 12 passes through the incident optical system 19 and enters the fifth phosphor layer 42 of the wavelength conversion member 41. By this incident light, the plurality of fifth phosphors 43 of the fifth phosphor layer 42 are excited to emit yellow light. The heat generated when the plurality of fifth phosphors 43 emit light is radiated by the high thermal conductive particles 44. A part of the light from the semiconductor light emitting element 12 passes through the fifth phosphor layer 42 and enters the second phosphor layer 14 of the wavelength conversion member 41. By this incident light, the plurality of second phosphors 17 of the second phosphor layer 14 are excited to emit blue light. These yellow light and blue light are mixed to become white light.

  In the above description, an example in which one of a plurality of wavelength conversion layers includes high thermal conductivity particles has been described. However, a plurality of wavelength conversion layers may include high thermal conductivity particles, and all wavelength conversion layers may have high thermal conductivity. It may contain particles.

  As described above, according to the fourth embodiment of the present disclosure, in addition to the same effects as those of the first embodiment, the fifth phosphor layer 42 further includes the high thermal conductive particles 44. The effect of suppressing the temperature rise of the wavelength conversion member 41 can be obtained.

(Fifth embodiment)
FIG. 5 shows a schematic configuration of a light source 50 according to the fifth embodiment of the present disclosure. The same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The light source 50 includes a wavelength conversion member 51, the semiconductor light emitting element 12, and a mirror 59. The mirror 59 can guide the light from the semiconductor light emitting element 12 to the wavelength conversion member 51 and move the irradiation position on the wavelength conversion member 51. The mirror 59 is, for example, a MEMS mirror. An incident optical system 58 that guides the light of the semiconductor light emitting element 12 to the mirror 59 may be provided between the mirror 59 and the semiconductor light emitting element 12.

  The wavelength conversion member 51 converts the light from the semiconductor light emitting element 12 into light having a longer wavelength. In the wavelength conversion member 51, the emission wavelength changes continuously or stepwise depending on the irradiated position. The wavelength conversion member 51 includes, for example, at least two wavelength conversion layers having different emission spectra. The ratio of the thicknesses of the at least two wavelength conversion layers having different emission spectra differs depending on the position. The ratio of the thicknesses of at least two wavelength conversion layers having emission spectra different from each other may change stepwise depending on the position, or may change continuously. Each wavelength conversion layer may contain a phosphor, and the volume concentration of the phosphor may be constant in each wavelength conversion layer. Furthermore, the volume concentration of the phosphor may be constant in the entire wavelength conversion layer.

  The peak wavelength of the emission spectrum of the wavelength conversion layer may be longer as the wavelength conversion layer is closer to the side on which the light from the semiconductor light emitting element 12 is incident, for example. For example, among the peak wavelengths of the emission spectrum of each wavelength conversion layer, the peak wavelength of the emission spectrum of the wavelength conversion layer closest to the side on which the light from the semiconductor light emitting element 12 is incident is the longest wavelength. The peak wavelength of the emission spectrum of the wavelength conversion layer farthest from the light incident side may be the shortest wavelength. At least one of the plurality of wavelength conversion layers may contain particles (high thermal conductivity particles) having a thermal conductivity of 10 W / (m · K) or more in addition to the phosphor particles. The wavelength conversion layer containing highly thermally conductive particles may be disposed closest to the semiconductor light emitting element among the plurality of wavelength conversion layers. At least one of the plurality of wavelength conversion layers may not contain the resin binder.

  The wavelength conversion member 51 includes, for example, a sixth phosphor layer 52 and a seventh phosphor layer 53 as the wavelength conversion layer. The sixth phosphor layer 52 and the seventh phosphor layer 53 are arranged so as to overlap each other, and the ratio of the thickness perpendicular to the irradiation surface irradiated with the light from the semiconductor light emitting element 12 is the irradiation position. Is provided so as to change continuously. For example, when the irradiation position on the wavelength conversion member 51 is moved in a predetermined direction from a predetermined position, the ratio of the thickness of the seventh phosphor layer 53 to the thickness of the sixth phosphor layer 52 is moved. Increases continuously.

  The sixth phosphor layer 52 includes a plurality of sixth phosphors 54 that emit light upon receiving light from the semiconductor light emitting element 12, and a binder 55 disposed between the plurality of sixth phosphors 54. . The seventh phosphor layer 53 includes a plurality of seventh phosphors 56 that emit light upon receiving light from the semiconductor light emitting element 12 through the sixth phosphor layer 52, and a plurality of seventh phosphors 56. And a binder 57 disposed therebetween.

  The sixth phosphor 54 is, for example, a yellow phosphor. The seventh phosphor 56 is, for example, a blue phosphor. The volume concentration of the sixth phosphor 54 may be constant in the sixth phosphor layer 52. Further, the volume concentration of the seventh phosphor 56 may be constant in the seventh phosphor layer 53. Further, the volume concentration of the sixth phosphor 54 and the volume concentration of the seventh phosphor 56 may be the same. The binders 55 and 57 are media, such as resin, glass, or a transparent crystal, for example. The binders 55 and 57 may be made of the same material or different materials.

  Next, the operation of the light source 50 will be described. The light emitted from the semiconductor light emitting element 12 passes through the incident optical system 58, is reflected by the mirror 59, and enters the sixth phosphor layer 52 of the wavelength conversion member 51. The incident light excites the plurality of sixth phosphors 54 of the sixth phosphor layer 52 to emit yellow light. A part of the light from the semiconductor light emitting element 12 passes through the sixth phosphor layer 52 and enters the seventh phosphor layer 53 of the wavelength conversion member 51. The incident light excites the plurality of seventh phosphors 56 of the seventh phosphor layer 53 to emit blue light. These yellow light and blue light are mixed to become white light.

  The mirror 59 is movably provided, and the irradiation position on the wavelength conversion member 51 can be moved. Since the thickness ratio between the sixth phosphor layer 52 and the seventh phosphor layer 53 varies depending on the irradiation position, the emission color of the wavelength conversion member 51 changes as the irradiation position moves.

  As described above, according to the fifth embodiment of the present disclosure, the wavelength conversion member 51 has a light emission wavelength that changes continuously or stepwise depending on the irradiation position. The emission color can be changed or adjusted. Further, by making the volume concentration of the phosphor constant in the wavelength conversion member, thermal conductivity can be ensured, and damage or the like can be suppressed due to a difference in thermal expansion coefficient.

(Sixth embodiment)
FIG. 6 shows a schematic configuration of a light source 60 according to the sixth embodiment of the present disclosure. The same members as those in the first and fifth embodiments are denoted by the same reference numerals, and the description thereof is omitted. The light source 60 includes a wavelength conversion member 51, the semiconductor light emitting element 12, and a drive unit 61. The drive unit 61 can move the irradiation position on the wavelength conversion member 51 by making the wavelength conversion member 51 movable. The drive unit 61 includes, for example, a motor, and holds the wavelength conversion member 51 movably. The drive unit 61 moves the irradiation position on the wavelength conversion member 51 by moving the wavelength conversion member 51 in a direction parallel to the irradiation surface, for example. Further, the wavelength conversion member 51 may have a disk shape, and the drive unit 61 may move the irradiation position on the wavelength conversion member 51 by rotating the wavelength conversion member 51. An incident optical system 19 that guides the light of the semiconductor light emitting element 12 to the wavelength converting member 51 may be provided between the wavelength converting member 51 and the semiconductor light emitting element 12.

  Next, the operation of the light source 60 will be described. The light emitted from the semiconductor light emitting element 12 passes through the incident optical system 19 and enters the sixth phosphor layer 52 of the wavelength conversion member 51. The incident light excites the plurality of sixth phosphors 54 of the sixth phosphor layer 52 to emit yellow light. A part of the light from the semiconductor light emitting element 12 passes through the sixth phosphor layer 52 and enters the seventh phosphor layer 53 of the wavelength conversion member 51. The incident light excites the plurality of seventh phosphors 56 of the seventh phosphor layer 53 to emit blue light. These yellow light and blue light are mixed to become white light.

  The drive unit 61 can hold the wavelength conversion member 51 movably and move the irradiation position on the wavelength conversion member 51. Since the thickness ratio between the sixth phosphor layer 52 and the seventh phosphor layer 53 varies depending on the irradiation position, the emission color of the wavelength conversion member 51 changes as the irradiation position moves.

  According to the sixth embodiment of the present disclosure, similarly to the fifth embodiment, the emission color can be changed or adjusted, and the volume concentration of the phosphor can be kept constant in the wavelength conversion member. By doing, while ensuring thermal conductivity, damage etc. can be suppressed to a difference in thermal expansion coefficient.

(Seventh embodiment)
FIG. 7 shows a schematic configuration of a light source 70 according to the seventh embodiment of the present disclosure. The same members as those in the sixth embodiment are denoted by the same reference numerals and description thereof is omitted. The light source 70 includes a wavelength conversion member 71, a plurality of semiconductor light emitting elements 12, and a drive unit 72. The semiconductor light emitting element 12 is, for example, an LED, a super luminescent diode (SLD), or a laser diode (LD). In the present embodiment, the case where the semiconductor light emitting element 12 is an LD will be described. The semiconductor light emitting element 12 may be one LD, or may be one in which a plurality of LDs are optically coupled. The semiconductor light emitting element 12 emits blue-violet light, for example.

  In the present embodiment, the case where the plurality of semiconductor light emitting elements 12 all have the same configuration will be described. However, even if some or all of the plurality of semiconductor light emitting elements 12 have different configurations and emit light of different wavelengths. Good. Between the wavelength conversion member 71 and the plurality of semiconductor light emitting elements 12, a plurality of incident optical systems 19 that guide the light of the plurality of semiconductor light emitting elements 12 to the wavelength conversion member 71 may be provided. The incident optical system 19 includes, for example, a lens, a mirror, and / or an optical fiber. The plurality of incident optical systems 19 may all have the same configuration, or some or all of them may have different configurations.

  The drive unit 72 controls on / off of each semiconductor light emitting element 12. The drive unit 72 can move the irradiation position on the wavelength conversion member 51 by, for example, turning on one of the semiconductor light emitting elements 12 and switching the semiconductor light emitting element 12 to be turned on. The driving unit 72 may change the irradiation pattern on the wavelength conversion member 51 by turning on the plurality of semiconductor light emitting elements 12 and switching the combination of the plurality of semiconductor light emitting elements 12 to be turned on. The drive unit 72 may change the light amount by changing the number of semiconductor light emitting elements 12 to be turned on.

  The wavelength converting member 71 converts the light from the semiconductor light emitting element 12 into light having a longer wavelength. In the wavelength conversion member 71, the emission wavelength changes continuously or stepwise depending on the irradiated position. The wavelength conversion member 71 includes, for example, at least two wavelength conversion layers having different emission spectra. The ratio of the thicknesses of the at least two wavelength conversion layers having different emission spectra differs depending on the position. The ratio of the thicknesses of at least two wavelength conversion layers having emission spectra different from each other may change stepwise depending on the position, or may change continuously. Each wavelength conversion layer may contain a phosphor, and the volume concentration of the phosphor may be constant in each wavelength conversion layer. Furthermore, the volume concentration of the phosphor may be constant in the entire wavelength conversion layer.

  The peak wavelength of the emission spectrum of the wavelength conversion layer may be longer as the wavelength conversion layer is closer to the side on which the light from the semiconductor light emitting element 12 is incident, for example. For example, among the peak wavelengths of the emission spectrum of each wavelength conversion layer, the peak wavelength of the emission spectrum of the wavelength conversion layer closest to the side on which the light from the semiconductor light emitting element 12 is incident is the longest, and from the semiconductor light emitting element 12 The peak wavelength of the emission spectrum of the wavelength conversion layer farthest from the light incident side may be the shortest wavelength. At least one of the plurality of wavelength conversion layers may contain particles (high thermal conductivity particles) having a thermal conductivity of 10 W / (m · K) or more in addition to the phosphor particles. The wavelength conversion layer containing highly thermally conductive particles may be disposed closest to the semiconductor light emitting element among the plurality of wavelength conversion layers. At least one of the plurality of wavelength conversion layers may not contain the resin binder.

  The wavelength conversion member 71 includes, for example, a seventh phosphor layer 53, an eighth phosphor layer 73, and a ninth phosphor layer 74 as wavelength conversion layers. The seventh phosphor layer 53, the eighth phosphor layer 73, and the ninth phosphor layer 74 are arranged so as to overlap with each other and are perpendicular to the irradiation surface irradiated with the light from the semiconductor light emitting element 12. The thickness ratio is continuously changed depending on the irradiation position. For example, when the irradiation position on the wavelength conversion member 71 is moved from a predetermined position in a predetermined direction, the eighth phosphor layer 73 and the ninth fluorescence with respect to the thickness of the seventh phosphor layer 53 are moved. The thickness ratio of the body layer 74 increases continuously.

  The eighth phosphor layer 73 includes a plurality of eighth phosphors 75 that emit light upon receiving light from the semiconductor light emitting element 12, and a binder 76 disposed between the plurality of eighth phosphors 75. . The ninth phosphor layer 74 includes a plurality of ninth phosphors 77 that emit light upon receiving light from the semiconductor light emitting element 12 via the eighth phosphor layer 73, and a plurality of ninth phosphors 77. And a binder 78 disposed therebetween.

  The eighth phosphor 75 is, for example, a red phosphor. The ninth phosphor 77 is, for example, a green phosphor. The phosphor volume concentrations of the seventh phosphor layer 53, the eighth phosphor layer 73, and the ninth phosphor layer 74 may be constant in each layer, or may be constant in all layers. May be. The binders 76 and 78 are media, such as resin, glass, or a transparent crystal, for example. The binders 57, 76 and 78 may be made of the same material or different materials.

  Next, the operation of the light source 70 will be described. The light emitted from the plurality of semiconductor light emitting elements 12 or any one of them passes through the corresponding incident optical system 19 and enters the eighth phosphor layer 73 of the wavelength conversion member 71. By this incident light, the plurality of eighth phosphors 75 of the eighth phosphor layer 73 are excited to emit red light. A part of the light from the semiconductor light emitting element 12 passes through the eighth phosphor layer 73 and enters the ninth phosphor layer 74 of the wavelength conversion member 71. The incident light excites the plurality of ninth phosphors 77 of the ninth phosphor layer 74 to emit green light. A part of the light from the semiconductor light emitting element 12 passes through the ninth phosphor layer 74 and enters the seventh phosphor layer 53 of the wavelength conversion member 71. The incident light excites the plurality of seventh phosphors 56 of the seventh phosphor layer 53 to emit blue light. These red light, green light and blue light are mixed to become white light.

  In the above, the case where the wavelength conversion member has three phosphor layers has been described, but instead of this, a wavelength conversion member having two phosphor layers is used as in the fifth and sixth embodiments. Also good. In the fifth and sixth embodiments, instead of the wavelength conversion member having two phosphor layers, a wavelength conversion member having three phosphor layers may be used as in the present embodiment.

  As described above, according to the seventh embodiment of the present disclosure, in addition to the same effects as those of the fifth and sixth embodiments, a wavelength conversion member having three phosphor layers is used. The same effect as in the second embodiment can be obtained.

(Eighth embodiment)
FIG. 8 shows a schematic configuration of a vehicle headlamp 120 according to the eighth embodiment of the present disclosure. The vehicle headlamp 120 according to the present embodiment emits light from any one of the light sources 10, 20, 30, 40, 50, 60 and 70 of the first to seventh embodiments and guides light from the light source forward. And an optical system 122. You may provide the wavelength cut filter 121 which absorbs or reflects so that the blue-violet light from the semiconductor light-emitting device of a light source may not come outside. The emission optical system 122 is, for example, a reflector. The emission optical system 122 includes, for example, a metal film such as Al or Ag, or an Al film having a protective film formed on the surface. The vehicle headlamp 120 may be a so-called reflector type or a projector type. In the present disclosure, the vehicle includes an automobile, a two-wheeled vehicle, and a special vehicle.

  According to the eighth embodiment, the effects of the first to seventh embodiments can be obtained in the vehicle headlamp.

(Ninth embodiment)
FIG. 12 shows a schematic configuration of a vehicle 130 according to the ninth embodiment of the present disclosure. The vehicle 130 includes the vehicle headlamp 120 and the power supply source 131 according to the eighth embodiment. The vehicle 130 may have a generator 132 that is rotationally driven by a drive source such as an engine and generates electric power. The power generated by the generator 132 is stored in the power supply source 131. The power supply source 131 is a secondary battery that can be charged and discharged. The vehicle headlight 120 is turned on by power from the power supply source 131. The vehicle 130 is, for example, an automobile, a motorcycle, or a special vehicle. Furthermore, the vehicle 130 may be an engine vehicle, an electric vehicle, or a hybrid vehicle.

  According to the ninth embodiment, the effects of the first to seventh embodiments can be obtained in the vehicle.

  The first to ninth embodiments can be appropriately combined.

  The wavelength conversion member of this indication can be used for light sources, such as special lighting, a head up display, a projector, and a vehicular headlamp, for example.

10, 20, 30, 40, 50, 60, 70 Light source 11, 27, 31, 41, 51, 71 Wavelength converting member 12, 84, 85 Semiconductor light emitting element 13, 14, 21, 22, 42, 52, 53, 73, 74 Phosphor layer 15, 17, 23, 25, 43, 54, 56, 75, 77 Phosphor 16, 18, 24, 26, 55, 57, 76, 78 Binder 19, 58 Incident optical system 32 Phosphor Sintered body layer 44 High thermal conductivity particle 59 Mirror 62, 72 Drive unit 120 Vehicle headlamp 121 Wavelength cut filter 122 Emission optical system 130 Vehicle 131 Power supply source 132 Generator

Claims (12)

  A wavelength conversion member comprising a phosphor that converts light from a semiconductor light emitting element into light having a longer wavelength, wherein the wavelength conversion member includes at least two wavelength conversion layers having different emission spectra, The wavelength conversion member in which the peak wavelength of the emission spectrum of the wavelength conversion layer is longer in the layer on the side where light from the semiconductor light emitting element is incident.   The wavelength conversion member according to claim 1, wherein at least one of the wavelength conversion layers does not contain a resin binder.   The wavelength conversion member according to claim 1 or 2, wherein at least one of the wavelength conversion layers contains particles having a thermal conductivity of 10 W / (m · K) or more in addition to the phosphor particles.   The wavelength conversion member according to claim 3, wherein a wavelength conversion layer containing particles having a thermal conductivity of 10 W / (m · K) or more is disposed closest to the semiconductor light emitting element among the wavelength conversion layers.   The light source which comprises the wavelength conversion member of any one of Claims 1-4.   A wavelength conversion member made of a phosphor that converts light from a semiconductor light emitting element into light having a longer wavelength, and the emission color changes continuously or stepwise depending on the position where the excitation light is irradiated.   The wavelength conversion member according to claim 6, comprising at least two wavelength conversion layers having different emission spectra, wherein the ratio of the thicknesses of the different layers is continuously different.   A light source comprising the wavelength conversion member according to claim 6 or 7 and comprising a semiconductor laser as a semiconductor light emitting device.   The light source according to claim 8, wherein the irradiation position of the excitation light to the wavelength conversion member by the semiconductor laser is controlled using a movable mirror.   The light source according to claim 8, wherein the irradiation position of the excitation light to the wavelength conversion member by the semiconductor laser is controlled by making the wavelength conversion member movable.   The light source according to claim 8, wherein the irradiation position of the excitation light to the wavelength conversion member is controlled by lighting control of a plurality of semiconductor lasers.   A vehicle headlamp comprising the light source according to any one of claims 5 and 8-11.

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