JP2017098095A - Light emitting device, vehicular lighting fixture, display device and wavelength conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device capable of reducing both blur of a light distribution pattern and color unevenness.SOLUTION: A light emitting device includes: a light source; and a wavelength conversion part for performing wavelength conversion on at least one part of the light emitted from the light source. The wavelength conversion part includes: a base plate 201; and a phosphor layer 50 arranged on the base plate 201. The phosphor layer 50 includes: a first phosphor layer 203; and a second phosphor layer 204. Each of the first and second phosphor layers 203, 204 is constituted in such a manner that phosphor containing plates having predetermined shapes are arrayed in two dimensions on a principal plane with an interval with predetermined width. Phosphor containing plates 205b of the second phosphor layer 204 are arranged so as to cover gaps of phosphor containing plates 205a of the first phosphor layer 203.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light emitting device, and more particularly to a light emitting device including a wavelength conversion unit.

  For example, Patent Documents 1 and 2 disclose light-emitting devices that perform wavelength conversion by causing light emitted from a light-emitting element such as an LED or a semiconductor laser to enter a substrate on which a phosphor layer is disposed and converting a part of the light into fluorescence. Has been.

  Patent Document 1 discloses a phosphor layer in which phosphor particles are dispersed in a translucent binder. A depression is provided in the surface of the binder between the phosphor particles on the surface of the phosphor layer, and a light scattering layer is disposed in this depression. Therefore, light that passes through the binder and is about to be emitted from the surface of the binder is scattered by the light scattering layer, returned to the phosphor particle side, and converted into fluorescence, so that the excitation light emitted from the light emitting element is It is possible to prevent light from being emitted from the surface through only the binder, and color unevenness can be suppressed.

  Patent Document 2 discloses a configuration in which a phosphor plate as a phosphor layer is provided and the phosphor plate is divided into a plurality of regions (partitions) by a partition member. As the partition member, a reflection member containing a metal material is used. With this configuration, the fluorescence emitted in the phosphor plate is repeatedly reflected on the upper and lower surfaces of the phosphor plate, propagates in the phosphor plate, is emitted outwardly from the incident light beam, and is emitted. As the diameter increases, the phenomenon that the fluorescence intensity increases toward the outer peripheral side of the outgoing light beam can be prevented.

JP 2013-197259 A JP 2013-102078 A

  The technique described in Patent Document 1 can improve color unevenness caused by excitation light passing through only a binder and emitted. In addition, due to the refractive index difference between the phosphor particles and the binder, the fluorescence that is going to propagate in the in-plane direction within the phosphor layer is reflected at the interface between the phosphor particles and the binder, so that the fluorescence propagates in the in-plane direction. Thus, the phenomenon of spreading outwards (the blurring of the light distribution pattern) seems to be improved to some extent. However, since the particle diameter of the phosphor particles varies, the thickness of the phosphor varies, which causes uneven color of the fluorescence.

  On the other hand, in the technique described in Patent Document 2, since the phosphor plate is used, the thickness is uniform, and the uneven color of the fluorescence is suppressed. Moreover, since the partition member prevents the propagation of fluorescence in the in-plane direction of the phosphor plate, the bleeding of the light distribution pattern is also improved. However, since the partition member is a reflective material, light is not emitted from the partition member portion on the upper surface of the phosphor plate, and a region corresponding to the partition member is projected darkly, resulting in color unevenness.

  An object of the present invention is to provide a light-emitting device capable of reducing both blurring of a light distribution pattern and color unevenness.

  In order to achieve the above object, the present invention provides a light emitting device having a light source and a wavelength conversion unit that converts the wavelength of at least a part of the light emitted from the light source. The wavelength conversion unit includes a substrate and a phosphor layer disposed on the substrate. The phosphor layer includes a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer. Each of the first and second phosphor layers has a configuration in which phosphor-containing plates having a predetermined shape are two-dimensionally arranged in the main plane with a gap of a predetermined width. The phosphor-containing plate of the second phosphor layer is disposed so as to cover the gap between the phosphor-containing plates of the first phosphor layer.

  According to the present invention, since the phosphor-containing plates are arranged with a gap, it is possible to prevent the fluorescence from propagating in the in-plane direction and reduce the bleeding of the light distribution pattern. In addition, since the phosphor-containing plate of the second phosphor layer is disposed so as to cover the gap between the phosphor-containing plates of the first phosphor layer, the excitation light is prevented from being emitted only through the gap. Color unevenness.

Schematic diagram showing an example of the configuration of the light emitting device according to the first embodiment The figure explaining the cross-section of the wavelength conversion part of 1st embodiment, and the course of excitation light The figure explaining the cross-sectional structure which expanded the area | region A of FIG. 2, and the side reflection of fluorescence 2A is a top view of the wavelength conversion unit in FIG. 2, and FIG. 2B is an enlarged view of a region M in FIG. (A) Sectional drawing of the wavelength conversion part which filled the gap | interval s of 1st embodiment with the binder, (b) is a top view of figure (a). (A) Sectional drawing of the wavelength conversion part provided with the reflecting film between the board | substrate and fluorescent substance layer of 1st embodiment, (b) is a top view of figure (a). The expanded sectional view of the wavelength conversion part provided with the film | membrane on the side surface of the fluorescent substance containing plate of 1st embodiment. The expanded sectional view of the wavelength conversion part provided with the film | membrane of the other example on the side surface of the fluorescent substance containing plate of 1st embodiment. (A) Sectional drawing of wavelength conversion part of 2nd embodiment, (b) is top view of figure (a). The block diagram which shows the structure of the vehicle lamp of 3rd embodiment. The block diagram which shows the structure of the head-up display apparatus of 4th embodiment. (A)-(d) Sectional drawing which shows the manufacturing process of Example 1. FIG.

An embodiment of the present invention will be described.
<First embodiment>
As a first embodiment, a light emitting device will be described with reference to FIG.

  As shown in FIG. 1, the light emitting device 10 of the present embodiment includes a light source 12 and a wavelength conversion unit (wavelength conversion device) 18 that converts the wavelength of at least part of light emitted from the light source 12. As illustrated in FIG. 2, the wavelength conversion unit 18 includes a substrate 201 and a phosphor layer 50 disposed on the substrate 201. The phosphor layer 50 includes a first phosphor layer 203 disposed on the substrate 201 and a second phosphor layer 204 disposed on the first phosphor layer 203.

  The first phosphor layer 203 is configured by two-dimensionally arranging phosphor-containing plates 205a having a predetermined shape. A gap s having a predetermined width is provided between the adjacent phosphor-containing plates 205a. Similarly, the second phosphor layer 204 is configured by two-dimensionally arranging phosphor-containing plates 205b having a predetermined shape. A gap s having a predetermined width is provided between the adjacent phosphor-containing plates 205b. At this time, the phosphor-containing plate 205b is disposed so as to cover the gap s between the phosphor-containing plates 205a of the first phosphor layer 203.

  The phosphor-containing plates 205a and 205b contain a phosphor that emits fluorescence when excited by light from the light source 12 (hereinafter referred to as excitation light).

  The wavelength conversion unit 18 is disposed at a position where the excitation light from the light source 12 is incident substantially in the thickness direction. The diameter of the light beam of the excitation light is smaller than the size in the in-plane direction of the wavelength conversion unit 18, and the wavelength conversion unit 18 converts the wavelength of the irradiation pattern (light distribution pattern) of the light beam of the excitation light and emits it outward. To project. The surface on which the excitation light from the light source 12 is incident on the wavelength conversion unit 18 may be on the substrate 201 side or the surface on the phosphor layer 50 side. As the substrate 201, a substrate that transmits the excitation light emitted from the light source 12 is used.

  The excitation light incident on the substrate 201 passes through the substrate 201 and reaches the first phosphor layer 203, and most of the light enters the phosphor-containing plate 205a as shown in paths C and D in FIG. The part enters the gap s of the first phosphor layer 203 as in the path E. Excitation light (C, D) incident on the phosphor-containing plate 205a excites the contained phosphor. Thereby, inside the phosphor-containing plate 205a of the first phosphor layer 203, fluorescence is emitted from the phosphor in all directions.

  Of the emitted fluorescence, the fluorescence that travels from the inside of the phosphor-containing plate 205a toward the upper second phosphor layer 204 passes through the phosphor-containing plate 205b of the second phosphor layer 204, or the second The light passes through the gap s of the phosphor layer 204 and is emitted to the outside. Fluorescence traveling from the inside toward the lower substrate 201 is partially reflected at the interface with the substrate, travels upward, passes through the second phosphor layer 204, and is emitted.

  On the other hand, among the fluorescence emitted from the phosphors in the phosphor-containing plate 205a, the fluorescence proceeding in the in-plane direction reaches the side surface of the phosphor-containing plate 205a and is reflected on the side surface, as shown in FIG. Returned to the inside of the body-containing plate 205a. Fluorescence directed toward the upper second phosphor layer 204 due to reflection on the side surface passes through the second phosphor layer 204 and is emitted to the outside. A part of the fluorescent light traveling in the direction of the lower substrate 201 is reflected at the interface with the substrate 201 and emitted through the second phosphor layer 204.

  As a result, the fluorescent light traveling in the in-plane direction within the phosphor-containing plate 205a passes through the gap s in the in-plane direction and enters the adjacent phosphor-containing plate 205a, further proceeds in the in-plane direction, and in the in-plane direction. Propagation can be suppressed. Therefore, it is possible to prevent the fluorescence from spreading out to the outer peripheral side in the in-plane direction from the light beam diameter of the excitation light incident on the wavelength conversion unit 18 from the light source 12 and emitted from the wavelength conversion unit 18 to cause bleeding of the light distribution pattern. Can do.

  In addition, the excitation light that has reached the second phosphor layer 204 through the path C in FIG. 2 is incident on the phosphor-containing plate 205b of the second phosphor layer 204, and excites the phosphor in the phosphor-containing plate 205b. Fluorescence is emitted from the phosphor in all directions. Of the emitted fluorescence, the fluorescence that travels upward is emitted to the outside from the upper surface of the phosphor-containing plate 205b. The fluorescence that travels downward is partially reflected at the interface with the first phosphor layer 203 and emitted upward toward the outside. Further, the fluorescence traveling in the in-plane direction is reflected by the side surface as shown in FIG. 3 and returned to the inner side of the phosphor-containing plate 205b. As a result, the fluorescent light traveling in the in-plane direction within the phosphor-containing plate 205b passes through the gap s in the in-plane direction, enters the adjacent phosphor-containing plate 205b, and further propagates in the in-plane direction. Can be suppressed. Therefore, bleeding of the light distribution pattern can be prevented.

  On the other hand, as shown in the path E of FIG. 2, the excitation light that has entered the gap s of the first phosphor layer 203 passes through the gap s, reaches the second phosphor layer 204, and covers the gap s. The fluorescence of the phosphor-containing plate 205b is excited in the same manner as the excitation light that has entered the phosphor-containing plate 205b of the second phosphor layer 204 and has reached the phosphor-containing plate 205b through the path C described above.

  Further, as shown in the path D of FIG. 2, the excitation light that enters the gap s of the second phosphor layer 204 after passing through and passing through the first phosphor layer 203 is emitted to the outside as it is.

  As apparent from the paths D, E, and C of FIG. 2, the excitation light emitted from the light source 12 and incident in the thickness direction of the wavelength conversion unit 18 is at least one of the first and second phosphor layers 203 and 204. Pass through the layers. Therefore, a part of the excitation light (for example, blue light) can be converted into fluorescence (yellow light), and can be emitted as mixed light (white light) of fluorescence and excitation light. Color unevenness in the main plane direction of light can also be suppressed.

  Further, part of the excitation light incident on the first and second phosphor layers 203 and 204 is scattered by the phosphor and proceeds in the in-plane direction, but the side surfaces of the phosphor-containing plates 205a and 205b are similar to the fluorescence. Therefore, it is possible to prevent the light from entering the adjacent phosphor-containing plates 205a and 205b beyond the gap s and propagating in the in-plane direction. Therefore, the excitation light propagates in the in-plane direction to excite the phosphor to generate fluorescence, and the fluorescence is emitted from the upper surface of the phosphor-containing plate 205b, or the propagated excitation light itself becomes fluorescent due to scattering. It can be prevented from being emitted from the upper surface of the body-containing plate 205b, and bleeding of the light distribution pattern of excitation light can be suppressed.

  As described above, by using the wavelength conversion unit 18 of the present embodiment, it is possible to prevent bleeding of the light distribution pattern due to the fluorescence projection pattern spreading outside the projection pattern of the excitation light. Color unevenness of the emitted light can also be prevented.

  The size of the phosphor-containing plates 205a and 205b in the main plane direction (in-plane direction) is preferably smaller than the diameter of the luminous flux of the excitation light incident on the wavelength conversion unit 18 from the light source 12. Thereby, the blur of a light distribution pattern can be suppressed effectively. As the size of the phosphor-containing plates 205a and 205b in the in-plane direction is smaller, the blur of the light distribution pattern can be reduced.

  The thicknesses of the phosphor-containing plates 205a and 205b are not particularly limited, but may be determined according to the required light color after wavelength conversion.

  The shape and arrangement pattern in the in-plane direction of the phosphor-containing plates 205a and 205b can be a desired shape and arrangement pattern. In order to further reduce the color unevenness, it is desirable to design the arrangement pattern so that the area of the gap s is reduced. For example, as shown in FIGS. 4A and 4B, the phosphor-containing plates 205a and 205b whose in-plane direction shape is square can be arranged vertically and horizontally in a matrix. FIGS. 4A and 4B are top views, but are hatched for easy understanding of the structure. The same applies to the other top views in this specification.

  The gap s between the phosphor-containing plates 205a and 205b of the first and second phosphor layers 203 and 204 is preferably filled with a material having a lower refractive index than the phosphor-containing plates 205a and 205b. For example, as shown in FIG. 2, the gap s can be configured to be filled with air, or as shown in FIGS. 5 (a) and 5 (b), than the phosphor-containing plates 205a and 205b. A configuration in which the phosphor is filled with a binder 202 having a low refractive index is also possible. In the case where the gap 202 is filled with the binder 202, the binder 202 is preferably transparent to the excitation light.

  As shown in FIGS. 6A and 6B, the excitation light incident on the phosphor layer 50 from the substrate 201 side passes between the substrate 201 and the phosphor layer 50, and the fluorescence emitted from the phosphor-containing plate. It is also possible to arrange a reflective film 901 that reflects the light. For example, a dichroic mirror can be used as the reflective film 901. As a result, among the fluorescence emitted from the first and second phosphor layers 203 and 204, the fluorescence proceeding to the substrate 201 side can be reflected by the reflective film 901. Therefore, the fluorescence from the upper surface of the second phosphor layer 204 can be reflected. The fluorescence extraction efficiency can be increased.

  Note that the dichroic mirror as the reflective film 901 may be disposed on the excitation light incident surface of the substrate 201 or may be disposed on both surfaces of the substrate 201.

  In order to improve the extraction efficiency of excitation light and fluorescence, the light incident surface and the light exit surface (upper surface and lower surface) of the phosphor-containing plates 205a and 205b are preferably mirror surfaces having no unevenness.

  The side surface of the phosphor-containing plate 205 is also preferably a mirror surface without irregularities in order to efficiently reflect fluorescence.

  Further, as shown in FIG. 7, a film 1001 for increasing the reflectance on the side surfaces of the phosphor-containing plates 205a and 205b can be disposed on the side surfaces of the phosphor-containing plates 205a and 205b. As the film 1001 for increasing the reflectance, a film having a refractive index lower than that of the phosphor-containing plates 205a and 205b can be used for at least light having a fluorescence wavelength. As the film 1001, an optical multilayer film in which a plurality of films having different refractive indexes is stacked can be used. Although FIG. 7 shows the case where the film 1001 is formed on both the phosphor-containing plates 205a and 205b, the film 1001 may be formed on only one of the phosphor-containing plates 205a and 205b. In any of the above examples, the film 1001 is preferably a light-transmitting film. By using the translucent film 1001, even if the film 1001 is formed on the side surface of the phosphor-containing plate 205b, light from the phosphor-containing plate 205a directly below is not blocked.

  In order to prevent scattering of light due to fine irregularities on the side surfaces of the phosphor-containing plates 205a and 205b and to increase the reflectance, the refractive index is equal to or higher than the refractive index of the phosphor-containing plate with respect to the light of the fluorescence wavelength. It is also possible to arrange a film 1002 having a large refractive index as shown in FIG. At this time, the gap s is configured to be filled with a binder 202 having a refractive index lower than that of the phosphor-containing plates 205a and 205b or air. As a result, the fluorescent light traveling in the in-plane direction through the phosphor-containing plates 205a and 205b passes through the side surfaces of the phosphor-containing plates 205a and 205b and is incident on the film 1002, and the interface between the film 1002 and the binder 202 or air. The inside of the phosphor-containing plates 205a and 205b can be returned by being reflected by i. Thereby, even if there are fine irregularities on the side surfaces of the phosphor-containing plates 205a and 205b, the fluorescence can be reflected with high efficiency, so that the phosphor-containing plates 205a and 205b can be easily processed.

  In the above description, the transmission type wavelength conversion unit 18 that causes excitation light emitted from the light source 12 to enter the wavelength conversion unit 18 from the lower surface side of the substrate 201 and emits fluorescence and excitation light from the upper surface side of the phosphor layer 50. However, it is also possible to adopt a configuration of the transmissive wavelength conversion unit 18 that allows excitation light to enter from the upper surface side of the phosphor layer 50 and emit fluorescence and excitation light from the lower surface side of the substrate 201. In addition, the reflection type wavelength conversion unit 18 is configured to allow excitation light to enter from the upper surface side of the phosphor layer 50 and to reflect and emit the excitation light and fluorescence at the interface between the phosphor layer 50 and the substrate 201. Is also possible. In the case of the reflective type, it is desirable to use a light reflective substrate such as a metal as the substrate 201, or arrange a reflective film that reflects both fluorescence and excitation light at the interface between the phosphor layer 50 and the substrate 201. .

The phosphor-containing plates 205a and 205b include phosphor ceramics that do not contain a binding member such as a resin, a phosphor powder dispersed in a binder with glass or resin, or a glass in which a luminescent center ion is added to a glass matrix. A plate made of phosphor or the like can be used. In the case where phosphor powder is dispersed in glass or resin, in order to suppress variation in the amount of fluorescence after wavelength conversion, it is desirable that the phosphor powder is a plate-shaped one that is compressed with high density and has no thickness unevenness. . For example, one or two or more phosphor powders having a predetermined composition are mixed and dispersed in glass containing components such as P ₂ O ₃ , SiO ₂ , B ₂ O ₃ , and Al ₂ O ₃ Can be used.

As the phosphors contained in the phosphor-containing plates 205a and 205b, those that are excited by the wavelength of the excitation light emitted from the light source 12 and emit fluorescence of a desired wavelength are used. Specifically, for example, when the wavelength of the excitation light emitted from the light source 12 is from the ultraviolet light to the blue light region, it is absorbed as follows and emits fluorescence of a desired wavelength (red, yellow, green). Can be used. For example, as phosphors emitting red fluorescence, 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 can be used. Examples of phosphors that emit yellow fluorescence include Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , Cax (Si, Al) ₁₂ (O, N) ₁₆ : Eu ^{2+, and the} like. Can be used. The phosphor emitting green ^{_{fluorescence, Lu 3 Al 5 O 12:}} Ce 3+, Y 3 (Ga, Al) 5 O 12: Ce 3+, Ca 3 Sc 2 Si 3 O 12: Ce 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+ and the} like can be used.

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. A nitride-based glass phosphor can be used.

  Further, as the phosphor ceramic, it is particularly desirable to use a phosphor ceramic having translucency. Translucent phosphor ceramics are phosphor ceramics that have become translucent because there are almost no pores or grain boundary impurities that cause light scattering in the sintered body. The conductivity is shown. For this reason, excitation light and fluorescence can be emitted without being lost by diffusion, and heat generated by the phosphor ceramic can be efficiently conducted and diffused to the substrate 201, the air, and the binder 202. Moreover, when using phosphor ceramics that do not exhibit translucency, those having as few pores and impurities as possible are desirable. 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.

  Since the material of the substrate 201 is preferably a transparent material in the case of the transmissive wavelength conversion unit 18, for example, a transparent material of metal oxide such as glass, sapphire, and magnesium oxide can be used. In order to increase the transmittance of the excitation light, the light incident surface and the light exit surface of the substrate 201 are preferably mirror surfaces having no unevenness.

  As shown in FIGS. 5A and 5B, when the gap 202 is filled with the binder 202, for example, a silicone resin or glass can be used.

When the reflective film 901 in FIGS. 6 and 7 is formed of a dichroic mirror, for example, a structure in which a plurality of SiO ₂ layers and TiO ₂ layers are alternately stacked can be used. Each layer thickness is designed to reflect fluorescence and transmit excitation light according to the wavelengths of fluorescence and excitation light.

<Second embodiment>
As a second embodiment, a light emitting device 10 in which the phosphor layer 50 of the wavelength conversion unit 18 has a structure of three or more layers will be described with reference to FIGS.

  In the first embodiment, the wavelength conversion unit 18 in which the phosphor layer 50 having the two-layer structure in which the second phosphor layer 204 is disposed on the first phosphor layer 203 is disposed on the substrate 201 has been described. Is not limited to the phosphor layer 50 having a two-layer structure, and three or more phosphor layers can be laminated as shown in FIGS. 9 (a) and 9 (b). Specifically, for example, as shown in FIG. 9A, the first phosphor layer 203 and the second phosphor layer 204 are arranged in this order from the substrate 201 side, and the third phosphor layer 253 is arranged thereon. . The first and second phosphor layers 203 and 204 have a configuration in which phosphor-containing plates 205a and 205b are two-dimensionally arranged with a gap s as in the first embodiment. The third phosphor layer 253 has a configuration in which phosphor-containing plates 205d are two-dimensionally arranged with a gap s.

  At this time, the first, second, and third phosphor layers 203, 204, and 253 are configured such that the positions of the gaps s are shifted from each other. As a result, as shown in FIG. 9A, the light beams J1 to J6 incident on the phosphor layer 50 from the light source 12 pass through the two or three phosphor layers, and are thus emitted from the phosphor layer 50. Color unevenness of the emitted light can be reduced. Other configurations and effects are the same as those of the first embodiment, and thus description thereof is omitted.

<Third embodiment>
As a third embodiment, a vehicle lamp using the light emitting device 10 of the first and second embodiments will be described with reference to FIG.

  The vehicular lamp in FIG. 10 includes any one of the light emitting devices 10 described in the first embodiment and the second embodiment, and a lens 20 that transmits light emitted from the light emitting device and emits the light to the outside.

  An optical deflector 30 is disposed between the light source 12 of the light emitting device 10 and the wavelength conversion unit 18 as an optical scanning unit. The optical deflector 30 deflects the excitation light R emitted from the light source 12 so that the incident position of the excitation light R on the wavelength conversion unit 18 is two-dimensionally formed into a desired pattern on the main plane of the wavelength conversion unit 18. To scan. The wavelength conversion unit 18 converts part of the scanned excitation light R that has been scanned into fluorescence, and mixes and emits the excitation light R that has passed through the wavelength conversion unit 18. The projection lens 20 enlarges and projects the light beam emitted from the wavelength conversion unit 18 in front of the vehicle. Thereby, a two-dimensional image corresponding to the pattern scanned by the optical deflector 30 is projected in front of the vehicle.

  Since the vehicular lamp according to the present embodiment uses any one of the wavelength conversion units 18 described in the first and second embodiments as the wavelength conversion unit 18, bleeding of the light distribution pattern emitted from the wavelength conversion unit 18 is blurred. And color unevenness is reduced. Therefore, it is possible to reduce blur and color unevenness of a two-dimensional image projected from the vehicle lamp to the front of the vehicle.

  As the light source 12, for example, a semiconductor light emitting element such as a laser diode (LD) that emits laser light in a blue region (for example, an emission wavelength of 450 nm) as excitation light can be used. As the phosphor contained in the phosphor layer 50 of the wavelength converter 18, a phosphor that emits yellow fluorescence in response to 450 nm excitation light is used. Thereby, the vehicular lamp can draw a desired pattern with white light in which blue excitation light and yellow fluorescence are mixed, and can project it in front of the vehicle.

  Moreover, it is also possible to project white light using two or more light sources 12 having different wavelengths. For example, a phosphor that includes a first light source 12 that emits blue light and a second light source 12 that emits red light, and a part of the blue light emitted from the first light source 12 is excited by blue light and emits green fluorescence. It is possible to draw a desired pattern of white light and project it in front of the vehicle by converting it into green light by the wavelength conversion unit 18 using and mixing with red light emitted from the second light source 12. In this case, the optical deflector 30 is disposed for each of the first light source 12 and the second light source 12, and the wavelength conversion unit 18 may be disposed only for the blue light emitted from the first light source 12.

  The light source 12 may emit light in the near ultraviolet region (for example, the emission wavelength is 405 nm). In this case, the wavelength conversion unit 18 uses, for example, a phosphor-containing plate that emits three colors of red, green, and blue so that the three colors of fluorescence are mixed. Since near-ultraviolet light is not visible, only white light in which three colors of fluorescence are mixed is visually recognized.

  The light source 12 is not limited to a laser, but may be an LED.

  The optical deflector 30 includes a mirror part (not shown), and a structure in which the excitation light R incident on the mirror part is two-dimensionally scanned by the mirror part swinging can be used. For example, a MEMS (Micro Electro Mechanical Systems) scanner can be used. The driving method of the optical deflector is roughly divided into a piezoelectric method, an electrostatic method, and an electromagnetic method, and any method may be used.

  The light deflector 30 may scan the excitation light with a plurality of types such as a low beam light distribution pattern or a high beam light distribution pattern.

  Although FIG. 10 shows an example in which the wavelength conversion unit 18 is disposed between the optical deflector 30 and the lens 20, the wavelength conversion unit 18 may be disposed between the light source 12 and the optical deflector 30. is there.

<Fourth embodiment>
As a fourth embodiment, a display device that forms an image by projecting light in a desired pattern using any one of the light emitting devices 10 described in the first and second embodiments will be described. As an example, a head-up display (HUD) device 1201 will be described with reference to FIG. The HUD device 1201 incorporates a light emitting device including the light source 12, the optical deflector 30, and the wavelength conversion unit 18. The light emitting device projects a desired pattern onto the front window 1205 of the vehicle. This desired pattern is reflected by the front window 1205 and enters the eyes of the observer 1207. This desired pattern is drawn so as to form a virtual image 1206 on an extension connecting the desired pattern with the observer 1207 (eyes). Therefore, the observer 1207 can visually recognize the scenery in front of the front window 1205 and the image of the virtual image 1206.

  By using any one of the light emitting devices described in the first and second embodiments as the light emitting device of such a HUD 1201 device, it is possible to reduce bleeding and color unevenness of a desired pattern projected on the front window 1205. Therefore, an image with excellent image quality can be displayed.

  In addition, the light-emitting device of this embodiment can be used not only for the vehicle lamp or the HUD device 1201 described above but also for general lighting, street lamps, headlamps, and the like.

<Example 1>
As a first embodiment, a manufacturing method of the wavelength conversion unit 18 of FIGS. 2, 3, and 4 in which the gap s is filled with air will be described with reference to FIG.

  First, the entrance surface and the exit surface of a sapphire wafer having a thickness of 0.5 mm are mirror-finished and cut into a predetermined size (10 mm * 10 mm) to prepare a substrate 201 (not shown).

Dicing is performed to a predetermined size of a phosphor plate (phosphor: YAG: Ce ³⁺ ) having a thickness of 0.05 mm (for example, 0.09 mm * 0.09 mm square) to prepare phosphor-containing plates 205a and 205b. Before dicing, the incident surface and the exit surface of the excitation light may be mirror finished.

  A silicone resin to be the bonding layer 1202 (see FIG. 3) is dropped onto a predetermined position of the cut sapphire substrate 201 using a dispenser (FIG. 12A). The amount of the silicone resin is adjusted so that the thickness of the bonding layer 1202 after curing is as thin as possible (for example, 1 μm or less). A phosphor-containing plate 205a for the first phosphor layer 203 is placed on the dropped silicone resin at a predetermined pitch d1 (d1 = 0.1 mm) by a die bonder or the like as shown in FIGS. 4A and 4B. (FIG. 12B). Thereafter, the silicone resin is cured (for example, at a curing condition of 150 ° C. for 4 hours), and the bonding layer 1202 is formed. As a result, the first phosphor layer 203 on which the phosphor-containing plates 205a are mounted in a matrix with a gap s of 0.01 mm is formed.

  Next, using a dispenser, a silicone resin that becomes the bonding layer 1202 is dropped onto a predetermined position on the plurality of phosphor-containing plates 205a arranged in a matrix (FIG. 12C). Using a die bonder or the like, the phosphor-containing plate 205b is mounted in a matrix at a pitch d1 (d1 = 0.1 mm) on the dropped silicone resin (FIG. 12 (d)). At this time, as shown in FIG. 4B, the side a2 and the side b2 of the corresponding phosphor-containing plate 205b are d2 and d3, respectively, with respect to the side a1 of the phosphor-containing plate 205a and the side b1 orthogonal thereto. It mounts so that it may shift (for example, d2 = d3 = 0.05 mm). Thereafter, the silicone resin is cured (for example, at a curing condition of 150 ° C. for 4 hours), and the bonding layer 1202 is formed. Thus, the phosphor-containing plate 205b is disposed so as to cover the gap s of the first phosphor layer 203, and the second phosphor layer 204 having a gap s of 0.01 mm is formed between the phosphor-containing plates 205b. Is done.

  As described above, the wavelength conversion unit 18 of FIGS. 2 to 4 in which the gap s is filled with air can be manufactured.

  In the manufacturing method described above, a method of dropping the silicone resin as the bonding layer 1202 onto the substrate 201 and the phosphor-containing plate 205a is used. However, the excitation light incident on the phosphor-containing plate 205a and the phosphor-containing plate 205b is incident. Silicone resin may be applied to the surface and bonded to the substrate 201 and the emission surface of the phosphor plate containing 205a.

<Example 2>
As a second embodiment, a method of manufacturing the wavelength conversion unit 18 in FIG. 5 in which the gap s is filled with the binder 202 will be described.

  The manufacturing method of the wavelength conversion unit 18 in FIG. 5 is almost the same as the manufacturing method of Example 1, but after the step of FIG. 12B, a silicone resin is dropped into the gap s of the phosphor-containing plate 205a. And then cured. Similarly, after the step of FIG. 12D, silicone resin is dropped and filled in the gap s of the phosphor-containing plate 205b, and then cured. Other steps are the same as those in the first embodiment.

  Thereby, the wavelength conversion unit 18 of FIG. 5 in which the gap s is filled with the binder 202 can be manufactured.

  In addition, when the fluorescent substance plate 205 is YAG (refractive index 1.8), as a material of the binder 202, the silicone resin of refractive index 1.4 can be used. The binder 202 and the bonding layer 1202 can be made of the same material or different materials.

<Example 3>
As Example 3, a manufacturing method of the wavelength conversion unit 18 of FIG. 6 provided with the reflective film 901 between the first phosphor layer 203 and the substrate 201 will be described.

The manufacturing method of the wavelength conversion unit 18 of FIG. 6 is almost the same as the manufacturing method of Example 1, but before the step of FIG. 12A, SiO ₂ is deposited on the upper surface of the sapphire substrate 201 by vapor phase growth or the like. A plurality of pairs of films and TiO ₂ films are alternately stacked with a predetermined thickness, and a dichroic mirror layer is formed as the reflective film 901. The predetermined film thickness is designed to reflect fluorescence and transmit excitation light. Other steps are the same as those in the first embodiment. Thereby, the wavelength conversion part 18 of FIG. 6 can be manufactured.

<Example 4>
As Example 4, a method of manufacturing the wavelength conversion unit 18 of FIG. 7 provided with the film 1001 on the side surfaces of the phosphor-containing plates 205a and 205b will be described.

The manufacturing method of the wavelength conversion unit 18 in FIG. 7 is almost the same as the manufacturing method of Example 3, but before the step of FIG. 12A, the vapor phase growth method is applied to the side surfaces of the phosphor-containing plates 205a and 205b. A plurality of sets of SiO ₂ films and TiO ₂ films are alternately stacked with a predetermined film thickness to form a film 1001. At this time, it is desirable to mask the phosphor-containing plates 205a and 205b so that they are not formed on the upper and lower surfaces. Other steps are the same as those in Example 3. Thereby, the wavelength conversion part 18 of FIG. 7 can be manufactured.

DESCRIPTION OF SYMBOLS 10 ... Light-emitting device, 12 ... Light source, 18 ... Wavelength conversion part (wavelength conversion apparatus), 20 ... Lens, 30 ... Optical deflector (light scanning part), 50 ... Fluorescence Body layer, 201 ... substrate, 203 ... first phosphor layer, 204 ... second phosphor layer, 205a, 205b ... phosphor-containing plate, 253 ... third phosphor layer, 901 ... Reflective film, 1001 ... Film, 1002 ... Film, 1201 ... Head-up display device (display device), 1202 ... Bonding layer

Claims (12)

A light source, and a wavelength conversion unit that converts the wavelength of at least part of the light emitted from the light source,
The wavelength conversion unit includes a substrate and a phosphor layer disposed on the substrate,
The phosphor layer includes a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer, and the first and second phosphor layers Each has a configuration in which phosphor-containing plates having a predetermined shape are two-dimensionally arranged in a main plane with a gap of a predetermined width, and the phosphor-containing plate of the second phosphor layer has the first fluorescence. A light emitting device, wherein the light emitting device is disposed so as to cover a gap between the phosphor-containing plates of the body layer.   2. The light emitting device according to claim 1, wherein a size of the phosphor-containing plate in the principal plane direction is smaller than a diameter of a light beam incident on the wavelength conversion unit from the light source. .   3. The light-emitting device according to claim 1, wherein the gap between the phosphor-containing plates of the first and second phosphor layers is filled with a substance having a lower refractive index than the phosphor-containing plate. A light emitting device characterized by comprising:   4. The light-emitting device according to claim 1, wherein a side surface of the phosphor-containing plate of the first and second phosphor layers has a refractive index lower than that of the phosphor-containing plate. A light-emitting device in which a film is disposed.   The light-emitting device according to any one of claims 1 to 3, wherein light emitted from the light source is provided on a side surface of the phosphor-containing plate of the first and second phosphor layers, and A light-emitting device, comprising: a reflection film that reflects at least a part of fluorescence emitted from the phosphor-containing plate when light emitted from a light source enters.   2. The light-emitting device according to claim 1, wherein a side surface of the phosphor-containing plate of the first and second phosphor layers has a refractive index equal to or greater than a refractive index of the phosphor-containing plate. And the gap is filled with a material having a lower refractive index than the phosphor-containing plate.   7. The light-emitting device according to claim 1, wherein light emitted from the light source is incident on the wavelength conversion unit from a lower surface side of the substrate and is contained in the phosphor-containing plate. The phosphor is excited by the light to emit fluorescence, and the fluorescence is emitted from the upper surface of the phosphor layer.   The light-emitting device according to claim 7, wherein excitation light incident on the phosphor layer from the substrate side passes between the substrate and the phosphor layer, and the fluorescence emitted by the phosphor-containing plate is emitted. A light-emitting device, wherein a reflective film that reflects light is disposed.   9. The light emitting device according to claim 1, wherein a position where a light beam emitted from the light source is incident on the wavelength conversion unit is scanned between the light source and the wavelength conversion unit. A light emitting device characterized in that an optical scanning unit is arranged. A vehicle lamp having a light emitting device and a lens that transmits light emitted from the light emitting device and emits the light to the outside,
The vehicular lamp, wherein the light-emitting device is the light-emitting device according to any one of claims 1 to 9.   10. A display device that forms an image by projecting light onto a desired pattern from the light emitting device, wherein the light emitting device is the light emitting device according to any one of claims 1 to 9. . A wavelength conversion device that includes a substrate and a phosphor layer disposed on the substrate, and converts the wavelength of at least part of incident light,
The phosphor layer includes a first phosphor layer disposed on the substrate and a second phosphor layer disposed on the first phosphor layer, and the first and second phosphor layers Each has a configuration in which phosphor-containing plates having a predetermined shape are two-dimensionally arranged in a main plane with a gap of a predetermined width, and the phosphor-containing plate of the second phosphor layer has the first fluorescence. A wavelength conversion device, which is disposed so as to cover a gap between the phosphor-containing plates in the body layer.

Images