WO2014203479A1

WO2014203479A1 - Light source, and vehicle headlamp equipped with light source

Info

Publication number: WO2014203479A1
Application number: PCT/JP2014/002935
Authority: WO
Inventors: 純久長崎; 白石　誠吾; 森本　廉; 山中　一彦
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2013-06-21
Filing date: 2014-06-03
Publication date: 2014-12-24
Also published as: JP2016154062A

Abstract

This light source (80) includes at least two types of semiconductor laser (84, 85), and a wavelength conversion member (81) which is illuminated by emitted light from the semiconductor lasers, and emits light of converted wavelength. The wavelength conversion member (81) includes at least a blue phosphor and a yellow phosphor (90). The semiconductor lasers (84, 85) may include at least a blue-violet semiconductor laser (84) and a blue semiconductor laser (85).

Description

Light source and vehicle headlamp having light source

The present disclosure relates to a semiconductor light emitting device, and more particularly, to a light source that converts the wavelength of light from a semiconductor laser using a phosphor, 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 conventional technology, there has been a demand for improvement in safety or luminous efficiency particularly when a laser diode is used as a semiconductor light emitting element.

The present disclosure has been made in view of the above problems, and provides a light source capable of improving at least one of safety and luminous efficiency.

A light source according to an aspect of the present disclosure includes at least two types of semiconductor lasers, and a wavelength conversion member that emits wavelength-converted light that is irradiated with light emitted from these semiconductor lasers. At least a blue phosphor and a yellow phosphor.

According to the present disclosure, at least one of safety and luminous efficiency can be improved.

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 vehicle headlamp which concerns on 4th Embodiment. It is a block diagram which shows schematic structure of the vehicle which concerns on 5th Embodiment.

A light source according to the first aspect (aspect) of the present disclosure includes at least two types of semiconductor lasers and a wavelength conversion member that emits wavelength-converted light that is irradiated with light emitted from these semiconductor lasers. The wavelength conversion member includes at least a blue phosphor and a yellow phosphor. In the light source according to the second aspect of the present disclosure, in the light source according to the first aspect, the semiconductor laser includes at least a blue-violet laser and a blue laser.

The light source according to the third aspect of the present disclosure is the light source according to the first or second aspect, wherein the blue phosphor is (Sr _1-x Ba _x ) ₃ MgSi ₂ O ₈ : Eu [where 0 <x < 1]. The light source according to the fourth aspect of the present disclosure is the light source according to any one of the first to third aspects, wherein the blue phosphor includes Sr ₅ (PO ₄ ) ₃ Cl: Eu. In the light source according to any one of the first to fourth aspects according to the fifth aspect of the present disclosure, the blue phosphor includes BaMgAl ₁₀ O ₁₇ : Eu.

The light source according to the sixth aspect of the present disclosure is the light source according to the first to fifth aspects, wherein the yellow phosphor is a phosphor having a garnet structure.

In the light source according to the seventh aspect of the present disclosure, in the light source according to the sixth aspect, the phosphor having a garnet structure is a ceramic sintered body having translucency. The light source according to the eighth aspect of the present disclosure is the light source according to the first to fifth aspects, wherein the yellow phosphor is (Ba _1-y Sr _y ) Si ₂ O ₂ N ₂ : Eu [where 0 ≦ y ≦ 1].

The light source according to the ninth aspect of the present disclosure is the light source according to the first to eighth aspects, in which the wavelength conversion member has at least first and second layers. The first layer is closer to the side on which light from the semiconductor laser is incident than the second layer, and includes a yellow phosphor. The second layer includes a blue phosphor. A vehicle headlamp according to a tenth aspect of the present disclosure includes the light source according to any one of the first to ninth aspects.

(First embodiment)
FIG. 1 shows a schematic configuration of a light source 80 according to the first embodiment of the present disclosure. The light source 80 includes a wavelength conversion member 81 and two or more types of semiconductor

light emitting elements

84 and 85. The semiconductor

light emitting elements

84 and 85 are, for example, an LED, a super luminescent diode (SLD), a laser diode (LD), or the like. In the present embodiment, the case where the semiconductor

light emitting elements

84 and 85 are two types of LDs will be described. Each of the semiconductor

light emitting elements

84 and 85 may be one LD, or may be one in which a plurality of LDs are optically coupled.

The semiconductor light emitting element 84 emits blue-violet light. In the present disclosure, blue-violet light refers to light having a peak wavelength of 380 nm to 420 nm. In the present embodiment, the case where the semiconductor light emitting element 84 emits light having a wavelength of 405 nm will be described. The semiconductor light emitting element 85 emits blue light. In the present disclosure, blue light refers to light having a wavelength of 420 nm or more and 480 nm or less. In the present embodiment, a case where the semiconductor light emitting element 85 emits light having a wavelength of 445 nm will be described.

The wavelength conversion member 81 converts the light from the semiconductor

light emitting elements

84 and 85 into light having a longer wavelength. The wavelength conversion member 81 includes at least two wavelength conversion layers having different emission spectra. Each wavelength conversion layer corresponds to any one of the semiconductor light emitting elements, and is arranged side by side so that light from the corresponding semiconductor light emitting element enters without passing through the other wavelength conversion layers. Each wavelength conversion layer may be disposed so as to be in contact with each other, or may be disposed separately.

In the present embodiment, the case where the wavelength conversion member 81 includes the first phosphor layer 82 and the second phosphor layer 83 as the wavelength conversion layer will be described. The first phosphor layer 82 includes a plurality of first phosphors 88 that emit light upon receiving light from the semiconductor light emitting element 84, and a binder 89 disposed between the plurality of first phosphors 88. . The second phosphor layer 83 includes a plurality of second phosphors 90 that emit light upon receiving light from the semiconductor light emitting element 85, and a binder 91 disposed between the plurality of second phosphors 90. . The first phosphor layer 82 and the second phosphor layer 83 are provided side by side so that light from the corresponding semiconductor

light emitting element

84 or 85 enters without passing through the other phosphor layer.

The second phosphor 90 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 90 _{_{_{is, Y 3 Al 5 O 12:}}} Ce ( hereinafter, YAG) may be _{_{_{a, (Ba 1-y Sr y}}} ) Si 2 O 2 N 2: Eu [ where, 0 ≦ y ≦ 1]. The first phosphor 88 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 first phosphor 88 may be Sr ₃ MgSi ₂ O ₈ : Eu (hereinafter, SMS). The first phosphor 88 includes BaMgAl ₁₀ O ₁₇ : Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, and (Sr _1-x Ba _x ) ₃ MgSi ₂ O ₈ : Eu [where 0 <x <1] may be used. The binders 89 and 91 are media, such as resin, glass, or a transparent crystal, for example. The binders 89 and 91 may be made of the same material or different materials.

Between the wavelength conversion member 81 and the semiconductor light emitting element 84, an incident optical system 86 that guides the light of the semiconductor light emitting element 84 to the first phosphor layer 82 may be provided. Between the wavelength conversion member 81 and the semiconductor light emitting element 85, an incident optical system 87 that guides the light of the semiconductor light emitting element 85 to the second phosphor layer 83 may be provided. The incident

optical systems

86 and 87 include, for example, a lens, a mirror, and / or an optical fiber.

Next, the operation of the light source 80 will be described. The light emitted from the semiconductor light emitting element 84 passes through the incident optical system 86 and enters the first phosphor layer 82 of the wavelength conversion member 81. By this incident light, the plurality of first phosphors 88 of the first phosphor layer 82 are excited to emit blue light. Further, the light emitted from the semiconductor light emitting device 85 passes through the incident optical system 87 and enters the second phosphor layer 83 of the wavelength conversion member 81. By this incident light, the plurality of second phosphors 90 of the second phosphor layer 83 are excited to emit yellow 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 blue phosphor and the yellow phosphor are excited by at least two types of semiconductor lasers. Therefore, the luminous efficiency can be improved by using excitation light corresponding to each phosphor. In particular, according to this embodiment, by exciting the blue phosphor in the blue-violet laser (e.g. SMS), yellow phosphor with a blue laser (e.g. _{_{_{YAG, (Ba 1-y Sr}}} y) Si 2 O 2 N 2: Eu [where 0 ≦ y ≦ 1] is excited. The SMS phosphor has a small decrease in light emission efficiency even at high light density excitation of a blue-violet (for example, 405 nm) laser. In addition, the YAG phosphor has a small decrease in light emission efficiency even at high light density excitation of a blue (for example, 445 nm) laser. Also, (Ba _1-y Sr _y ) Si ₂ O ₂ N ₂ : Eu [where 0 ≦ y ≦ 1] is excited by a blue (eg, 445 nm) laser rather than excited by a blue-violet (eg, 405 nm) laser. However, energy loss is reduced due to the difference in energy between blue-violet light and blue light. In the present disclosure, high light density means light density of 0.1 kW / cm ² or more. Therefore, it is possible to suppress a decrease in light emission efficiency even at a high light density. Further, since blue light is obtained by a phosphor, white light can be generated without emitting light from a blue laser to the outside.

(Second Embodiment)
FIG. 2 shows a schematic configuration of the light source 100 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 100 includes a wavelength conversion member 101 and semiconductor

light emitting elements

84 and 85. Incident

optical systems

104 and 105 that guide the light of the semiconductor

light emitting elements

84 and 85 to the wavelength converting member 101 may be provided between the wavelength conversion member 101 and the semiconductor

light emitting elements

84 and 85. The incident

optical systems

104 and 105 may guide the light of the semiconductor

light emitting elements

84 and 85 so that the irradiation positions on the wavelength conversion member 101 overlap, and the semiconductors so that the irradiation positions on the wavelength conversion member 101 do not overlap. The light from the

light emitting elements

84 and 85 may be guided.

The wavelength conversion member 101 converts the light from the semiconductor

light emitting elements

84 and 85 into light having a longer wavelength. The wavelength conversion member 101 includes at least two wavelength conversion layers having different emission spectra. The plurality of wavelength conversion layers are provided so that at least a part thereof overlaps. The wavelength conversion member 101 includes a third phosphor layer 102 and a fourth phosphor layer 103 as a wavelength conversion layer. The third phosphor layer 102 mainly includes a plurality of third phosphors 106 that emit light upon receiving light from the semiconductor light emitting element 85, and a binder 107 disposed between the plurality of third phosphors 106. Have The fourth phosphor layer 103 mainly includes a plurality of fourth phosphors 108 that emit light upon receiving light from the semiconductor light emitting element 84, and a binder 109 disposed between the plurality of fourth phosphors 108. Have

In the present embodiment, an example will be described in which the third phosphor layer 102 is provided at a position farther from the side on which light from the semiconductor

light emitting elements

84 and 85 is incident than the fourth phosphor layer 103. However, on the contrary, the third phosphor layer 102 is provided at a position closer to the side on which light from the semiconductor

light emitting elements

84 and 85 is incident than the fourth phosphor layer 103. Also good. The third phosphor 106 is, for example, a yellow phosphor. The fourth phosphor 108 is, for example, a blue phosphor. The

binders

107 and 109 are media, such as resin, glass, or a transparent crystal, for example. The

binders

107 and 109 may be made of the same material or different materials.

Next, the operation of the light source 100 will be described. Light emitted from the semiconductor light emitting element 84 passes through the incident optical system 104 and enters the fourth phosphor layer 103 of the wavelength conversion member 101. By this incident light, the plurality of fourth phosphors 108 in the fourth phosphor layer 103 are excited to emit blue light. A part of the light from the semiconductor light emitting element 85 passes through the fourth phosphor layer 103 and enters the third phosphor layer 102 of the wavelength conversion member 101. The incident light excites the plurality of third phosphors 106 of the third phosphor layer 102 to emit yellow light. These blue light and yellow light are mixed to become white light.

According to the second embodiment of the present disclosure, as in the first embodiment, a blue phosphor (for example, SMS) is mainly excited with a blue-violet laser, and a yellow phosphor (for example, with a blue laser), for example. YAG, (Ba _1-y Sr _y ) Si ₂ O ₂ N ₂ : Eu [provided that 0 ≦ y ≦ 1] is excited. Therefore, it is possible to suppress a decrease in light emission efficiency even at a high light density. Further, since blue light is obtained by a phosphor, white light can be generated without emitting light from a blue laser to the outside.

(Third embodiment)
FIG. 3 shows a schematic configuration of the light source 110 according to the third embodiment of the present disclosure. The same members as those in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted. The light source 110 includes a wavelength conversion member 111 and semiconductor

light emitting elements

84 and 85. Incident

optical systems

104 and 105 that guide the light of the semiconductor

light emitting elements

84 and 85 to the wavelength converting member 111 may be provided between the wavelength conversion member 111 and the semiconductor

light emitting elements

84 and 85. The incident

optical systems

104 and 105 may guide the light of the semiconductor

light emitting elements

84 and 85 so that the irradiation positions on the wavelength conversion member 111 overlap, and the semiconductors so that the irradiation positions on the wavelength conversion member 111 do not overlap. The light from the

light emitting elements

84 and 85 may be guided.

The wavelength conversion member 111 converts the light from the semiconductor

light emitting elements

84 and 85 into light having a longer wavelength. The wavelength conversion member 111 includes at least two wavelength conversion layers having different emission spectra. The plurality of wavelength conversion layers are provided so that at least a part thereof overlaps. 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 111 has the fourth phosphor layer 103 and the phosphor sintered body layer 112 as the wavelength conversion layer will be described. The phosphor sintered body layer 112 mainly receives light from the semiconductor light emitting element 85 and emits light. For example, the phosphor sintered body layer 112 has a peak wavelength of an emission spectrum of 540 nm or more and 590 nm or less. The phosphor sintered body layer 112 does not contain a resin binder. The phosphor sintered body layer 112 is, for example, a transparent YAG sintered body.

In the present embodiment, an example in which the phosphor sintered body layer 112 is provided at a position closer to the side on which light from the semiconductor

light emitting elements

84 and 85 is incident than the fourth phosphor layer 103 will be described. However, on the contrary, the phosphor sintered body layer 112 is provided at a position farther from the side on which the light from the semiconductor

light emitting elements

84 and 85 is incident than the fourth phosphor layer 103. Also good.

Next, the operation of the light source 110 will be described. The light emitted from the semiconductor light emitting element 85 passes through the incident optical system 105 and enters the phosphor sintered body layer 112. This incident light excites the phosphor sintered body layer 112 to emit yellow light. Part of the light from the semiconductor light emitting element 84 passes through the phosphor sintered body layer 112 and enters the fourth phosphor layer 103. By this incident light, the plurality of fourth phosphors 108 in the fourth phosphor layer 103 are excited to emit blue light. These blue light and yellow light are mixed to become white light.

According to the third embodiment of the present disclosure, in addition to the same effects as those of the first and second embodiments, the phosphor sintered body layer 112 does not contain a resin binder. The effect of reducing cracks due to the above can be obtained. Further, according to the third embodiment of the present disclosure, the layer including the yellow phosphor is provided at a position closer to the side on which the excitation light is incident than the layer including the blue phosphor. Therefore, when light is extracted from the side containing the yellow phosphor, it is possible to reduce the yellow light from being absorbed by the blue phosphor.

(Fourth embodiment)
FIG. 4 shows a schematic configuration of a vehicle headlamp 120 according to the fourth embodiment of the present disclosure. The vehicle headlamp 120 of this embodiment includes any one of the

light sources

80, 100, and 110 of the first to third embodiments, and an emission optical system 122 that guides light from the light source forward. 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 fourth embodiment, the effects of the first to third embodiments can be obtained in the vehicle headlamp.

(Fifth embodiment)
FIG. 5 shows a schematic configuration of a vehicle 130 according to the fifth embodiment of the present disclosure. The vehicle 130 includes the vehicle headlamp 120 and the power supply source 131 according to the fourth 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 headlamp 120 is turned on by the 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 fifth embodiment, the effects of the first to third embodiments can be obtained in the vehicle.

The first to fifth embodiments can be appropriately combined.

(Other embodiments)
The wavelength conversion member may be rotated by making the wavelength conversion member into a wheel shape, providing the fin for receiving the airflow in the wavelength conversion member, and feeding air into the wavelength conversion member. When the wavelength conversion member rotates, the irradiation position by the semiconductor light emitting element (for example, a semiconductor laser) moves. Furthermore, the wavelength conversion member and other portions may be separated by a glass wall or the like, and the wavelength conversion member may be rotated by sending air into the glass wall. The wavelength conversion member and the light emitting end of the optical fiber and other portions may be separated by a glass wall or the like, and the wavelength conversion member may be rotated by feeding air into the glass wall.

According to this embodiment, since the irradiation position moves, heat generation is dispersed, and the wavelength conversion member can be suppressed. Therefore, light emission efficiency can be increased.

The light source of the present disclosure can be used for, for example, special lighting, a head-up display, a projector, and a vehicle headlamp.

80, 100, 110

Light source

81, 101, 111

Wavelength converting member

84, 85 Semiconductor

light emitting device

82, 83, 102, 103

Phosphor layer

88, 90, 106, 108

Phosphor

89, 91, 107, 109

Binder

86, 87 , 104, 105 Incident optical system 112 Phosphor sintered body layer 120 Vehicle headlamp 121 Wavelength cut filter 122 Emitting optical system 130 Vehicle 131 Power supply source 132 Generator

Claims

At least two types of semiconductor lasers;
A wavelength conversion member that emits light that is irradiated with light emitted from the at least two types of semiconductor lasers and wavelength-converted; and
With
The wavelength conversion member is a light source including at least a blue phosphor and a yellow phosphor.
The light source according to claim 1, wherein the semiconductor laser includes at least a blue-violet laser and a blue laser.
The light source according to claim 1, wherein the blue phosphor contains (Sr 1-x Ba x ) 3 MgSi 2 O 8 : Eu [where 0 <x <1].
The light source according to any one of claims 1 to 3, wherein the blue phosphor contains Sr 5 (PO 4 ) 3 Cl: Eu.
The light source according to any one of claims 1 to 4, wherein the blue phosphor contains BaMgAl 10 O 17 : Eu.
The light source according to any one of claims 1 to 5, wherein the yellow phosphor is a phosphor having a garnet structure.
The light source according to claim 6, wherein the phosphor having a garnet structure is a ceramic sintered body having translucency.
The yellow phosphor, (Ba 1-y Sr y ) Si 2 O 2 N 2: Eu [ where, 0 ≦ y ≦ 1] light source according to any one of claims 1 to 5 containing.
The wavelength conversion member has at least first and second layers,
The first layer is closer to the side on which light from the semiconductor laser is incident than the second layer, and includes a yellow phosphor.
The light source according to any one of claims 1 to 8, wherein the second layer contains the blue phosphor.
A vehicle headlamp comprising the light source according to any one of claims 1 to 9.