JP2013026163A - Light-emitting device, vehicular headlight and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which is provided with a spot-changing mechanism enabled to change a position or a size of a spot of excitation light in a light-emitting part, in which chromaticity of emission light can be adjusted.SOLUTION: The headlight 1 is provided with light-emitting parts 4 each including a first phosphor cell emitting fluorescence of a first color with receipt of laser light emitted from a laser element 2 and a second phosphor cell emitting fluorescence of a second color with receipt of the laser light, and a support substrate 8 as well as a rail 9 enabled to change a position or a size of a spot of the laser light in the light-emitting part 4.

Description

  The present invention relates to a light emitting device, a lighting device, and a vehicle headlamp that generate emitted light by irradiating phosphor with excitation light.

  In recent years, semiconductor light emitting devices such as light emitting diodes (LEDs) and semiconductor lasers (LDs) are used as excitation light sources, and excitation light generated from these excitation light sources is emitted to light emitting units including phosphors. Research on light-emitting devices that use fluorescence generated by the above as emitted light (for example, illumination light) has become active.

  As an example of such a light emitting device, a white light emitting device described in Patent Document 1 can be given. In this white light emitting device, a red phosphor, a green phosphor, a blue phosphor, and a yellow phosphor are mixed in a sealing material for fixing a purple LED that emits 395 nm purple light. This configuration improves the color rendering properties of the emitted light.

Japanese Patent Laying-Open No. 2004-127988 (released on April 22, 2004)

  However, in the configuration of Patent Document 1, since a plurality of types of phosphors are mixed and sealed, the particle size and particle size distribution of the phosphors differ depending on the type of phosphors. Distribution may be non-uniform. For this reason, there arises a problem that it is difficult to extract light having a target chromaticity. In addition, it is difficult to change the chromaticity of light emitted from a light emitting device after the light emitting device is manufactured.

  In addition, in the structure of patent document 1, since the multistage excitation that another kind of fluorescent substance absorbs and excites fluorescence emitted from a certain fluorescent substance also arises, the problem that luminous efficiency falls also arises.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a light emitting device, a vehicle headlamp, and an illumination device that can adjust the chromaticity of emitted light. .

In order to solve the above problems, a light-emitting device according to the present invention provides
An excitation light source that emits excitation light;
A first phosphor cell that includes a first phosphor that emits fluorescence of a first color in response to excitation light emitted from the excitation light source; and a second that is different from the first color in response to the excitation light. A light emitting unit including a second phosphor cell including a second phosphor that emits color fluorescence,
The excitation light is irradiated as a spot to the light emitting unit,
A spot changing mechanism that can change the position or size of the spot in the light emitting unit is further provided.

  According to said structure, the 1st fluorescent substance cell and the 2nd fluorescent substance cell which are contained in a light emission part emit fluorescence in response to the excitation light radiate | emitted from the excitation light source. The first phosphor cell and the second phosphor cell contain phosphors of different colors and emit fluorescence of different colors.

  Further, by providing the spot changing mechanism, the position or size of the spot of the excitation light irradiated on the first phosphor cell and the second phosphor cell can be changed. By changing the position of the excitation light spot with respect to the light emitting unit, the relative amount of excitation light irradiated to the first phosphor cell and the second phosphor cell changes.

  As a result, the chromaticity of the emitted light emitted from the light emitting device can be adjusted.

  In addition, the first phosphor cell and the second phosphor cell are arranged in the same in-plane direction, and it is preferable that the first and second phosphor cells are irradiated with the excitation light. .

  When the first and second phosphor cells are stacked along the optical axis direction of the excitation light, it is difficult to change the relative amount of the excitation light irradiated to these phosphor cells.

  On the other hand, in the above configuration, since the first and second phosphor cells are arranged in the same in-plane direction, each phosphor cell can be changed by changing the position or size of the excitation light spot. The relative amount of excitation light irradiated can be easily adjusted.

The light emitting unit further includes a third phosphor cell including a third phosphor that emits fluorescence of a third color different from the first and second colors,
The first phosphor absorbs the fluorescence emitted by the second phosphor more efficiently than the fluorescence emitted by the third phosphor,
It is preferable that the third phosphor cell is disposed between the first phosphor cell and the second phosphor cell.

  According to said structure, multistage excitation is suppressed by arrange | positioning 3rd fluorescent substance between 1st fluorescent substance which absorbs the fluorescence which 2nd fluorescent substance emits efficiently, and 2nd fluorescent substance. Can do.

  Moreover, it is preferable that the phosphor cell including the phosphor having the highest temperature resistance among the plurality of types of phosphor cells is disposed at a position closest to the center of the spot.

  According to the above configuration, the phosphor cell including the phosphor having the highest temperature resistance is disposed at a position closest to the center of the spot of the excitation light having the highest power density, thereby improving the luminous efficiency of the entire light emitting unit. Can be increased.

The second phosphor cell is disposed at least at a part of the periphery of the first phosphor cell,
The spot changing mechanism preferably changes the size of the spot.

  According to said structure, the 2nd fluorescent substance cell is arrange | positioned in at least one part of the circumference | surroundings of the 1st fluorescent substance cell, and it irradiates each fluorescent substance cell by changing the magnitude | size of the spot of excitation light The relative amount of excitation light generated can be easily adjusted.

  Moreover, it is preferable that the plurality of types of phosphor cells are arranged in a matrix.

  With the above configuration, color unevenness due to the arrangement of a plurality of phosphor cells that emit different colors of fluorescence can be reduced.

  Moreover, it is preferable that the plurality of types of phosphor cells have a size that is equal to or smaller than a reference value that is defined based on the size of the spot.

  According to said structure, the magnitude | size of the phosphor cell is formed relatively small with respect to the spot of excitation light, and the color nonuniformity which arises by arrange | positioning the phosphor cell of a several color more effectively Can be reduced.

  Moreover, it is preferable that a partition wall that prevents transmission and absorption of light is provided between the phosphor cells of different types.

  According to said structure, since the fluorescence radiate | emitted from the phosphor cell of a certain color is interrupted | blocked by a partition, possibility that the said fluorescence will be absorbed by the phosphor cell of another color can be reduced. As a result, multistage excitation can be suppressed. Moreover, since there is little transmission and absorption of the excitation light by the partition and the fluorescence emitted from the phosphor cell, the fluorescence from the phosphor can be extracted efficiently.

  The partition preferably includes a material having high thermal conductivity.

  With the above configuration, the heat generated by the light emitting unit can be dissipated, and deterioration of the function of the light emitting unit due to heat can be prevented.

In order to solve the above problems, a light-emitting device according to the present invention includes an excitation light source that emits excitation light;
A light emitting unit that emits fluorescence in response to excitation light emitted from the excitation light source,
In addition to the fluorescence, a part of the excitation light is emitted to the outside as emitted light,
The excitation light is irradiated as a spot to the light emitting unit,
It is further characterized by further comprising a spot changing mechanism that can change the relative positional relationship between the light emitting unit and the spot or the size of the spot.

  According to said structure, the fluorescence which the light emission part emitted in response to the excitation light radiate | emitted from the excitation light source, and a part of excitation light are radiate | emitted outside as emitted light (for example, illumination light). The spot change mechanism can change the relative positional relationship between the light emitting part and the spot of the excitation light or the size of the spot of the excitation light, so that the excitation light converted into fluorescence is emitted outside without being converted into fluorescence. The relative amount with the excitation light can be changed. As a result, the chromaticity of the emitted light can be adjusted.

  Moreover, it is preferable that the said light emission part contains the some light emission part arrange | positioned at intervals.

  According to said structure, excitation light is irradiated as a spot with respect to the several light emission part arrange | positioned at intervals. Excitation light applied to the region between the light emitting units is emitted to the outside without being converted into fluorescence. Therefore, it is easy to adjust the ratio of the amount of excitation light emitted to the outside without being converted into fluorescence with respect to the entire amount of excitation light spot by appropriately setting the arrangement interval of the plurality of light emitting units. Can be.

  Further, a vehicle headlamp including the light emitting device and a lighting device including the light emitting device are also included in the technical scope of the present invention.

  As described above, the light emitting device according to the present invention is configured to include the spot changing mechanism that can change the position or size of the spot of the excitation light in the light emitting unit.

  The light-emitting device according to the present invention further includes a spot changing mechanism that can change the relative positional relationship between the light-emitting portion and the spot of the excitation light or the size of the spot.

  Therefore, there is an effect that the chromaticity of the emitted light can be adjusted.

It is sectional drawing which shows schematic structure of the headlamp which concerns on one Embodiment of this invention. (A) is a perspective view which shows the mechanism which changes the position of the light emission part with which the said headlamp is provided, (b) is sectional drawing which expanded and showed a part of support substrate. It is a top view which shows an example of a structure of the light emission part with which the said headlamp is provided. It is side surface sectional drawing which shows the structure of the said light emission part. It is a top view which shows the example of a change of the said light emission part. It is sectional drawing which shows schematic structure of the headlamp which concerns on another embodiment of this invention. It is a top view which shows the structure of the light emission part which can be used suitably for the said headlamp. It is a top view which shows another structure of the light emission part with which the said headlamp is provided. It is a figure for demonstrating the method to pattern phosphor by photolithography. It is a figure for demonstrating the formation method of the partition formed between fluorescent substance cells. It is sectional drawing which shows the structure of the light emission part used when using a part of excitation light as illumination light. It is sectional drawing which shows the structure which provides a scattering part around the several light emission part. It is a figure for demonstrating the manufacturing method of a several light emission part.

[Embodiment 1]
One embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a headlamp (vehicle headlamp) will be described as an example of the light emitting device (illumination device) of the present invention. However, the light-emitting device of the present invention may be applied not only to a headlamp but also to a light-emitting device such as an electronic sign or a traffic light equipped with the light-emitting device, and a lighting device.

  A downlight can be mentioned as an example of the illuminating device of this invention. A downlight is a lighting device installed on the ceiling of a structure such as a house or a vehicle. In addition, the illumination device of the present invention may be realized as a headlamp of a moving object other than a vehicle (for example, a human, a ship, an aircraft, a submersible, a rocket, etc.), a searchlight, a projector, and a downlight It may be realized as a room lighting device other than (such as a stand lamp).

<Configuration of headlamp 1>
FIG. 1 is a cross-sectional view showing a schematic configuration of a headlamp 1 according to an embodiment of the present invention. As shown in FIG. 1, the headlamp 1 includes a laser element (excitation light source) 2, a lens 3, a light emitting unit 4, a reflector (reflecting mirror) 5, a metal base 7, a support substrate 8, and a rail (spot changing mechanism) 9. I have.

  In the headlamp 1 of the present embodiment, the light emitting unit 4 containing a fluorescent material is irradiated with laser light as excitation light to generate fluorescence in the light emitting unit 4 and use the fluorescence as illumination light. However, instead of the laser element 2 in the headlamp 1, an LED may be used as an excitation light source.

(Laser element 2)
The laser element 2 is a semiconductor laser that functions as an excitation light source that emits excitation light. A plurality of laser elements 2 may be provided. In this case, laser light as excitation light is oscillated from each of the plurality of laser elements 2. Although only one laser element 2 may be used, it is easier to use a plurality of laser elements 2 in order to obtain a high-power laser beam.

  The laser element 2 may have one light emitting point on one chip, or may have a plurality of light emitting points on one chip. The laser light of the laser element 2 is, for example, near ultraviolet light (for example, 405 nm), but the wavelength of the laser light is not limited to this, and may be appropriately selected according to the type of phosphor included in the light emitting unit 4. Good. A specific example of the combination of the wavelength of the excitation light and the type of phosphor included in the light emitting unit 4 will be described later.

  The laser light emitted from the laser element 2 is irradiated to the light emitting unit 4 as a spot. The arrangement of the laser elements 2 is defined so that this spot is positioned at a substantially focal position of the reflector 5. Further, at least a part of the light emitting unit 4 is disposed at a substantially focal position of the reflector 5. Therefore, the optical path of the fluorescence emitted from the light emitting unit 4 upon receiving the laser light is reflected by the reflecting surface of the reflector 5.

(Lens 3)
The lens 3 is a lens for adjusting the irradiation range of the laser light so that the laser light emitted from the laser element 2 is irradiated to the light emitting unit 4 as a spot having an appropriate size. It is arranged.

(Light emitting part 4)
The light emitting unit 4 is a light emitting element that receives the laser light emitted from the laser element 2 and emits fluorescence (emitted light), and includes a phosphor (fluorescent material) that emits light upon receiving the laser light. The light emitting unit 4 is provided on a support substrate 8 disposed on the surface of the metal base 7 (opposite surface facing the reflecting surface of the reflector 5), and at least a part of the light emitting unit 4 is a focal position of the reflector 5. Placed in.

  FIG. 2A is a perspective view showing a mechanism for changing the position of the light emitting unit 4, and FIG. 2B is a cross-sectional view showing an enlarged part of the support substrate 8. FIG. 3 is a top view illustrating an example of the configuration of the light emitting unit 4. As shown in FIGS. 2A and 3, the light emitting unit 4 receives the excitation light emitted from the laser element 2 and emits red (first color) fluorescence (first phosphor). A red phosphor cell 4R (first phosphor cell) containing blue and a blue phosphor cell 4B (first phosphor cell) containing blue phosphor (second phosphor) that emits blue (second color) fluorescence upon receiving laser light. 2 phosphor cells) and a green phosphor cell 4G (third phosphor cell) including a green phosphor (third phosphor) that emits green (third color) fluorescence upon receiving laser light. Yes.

  In this configuration, the three phosphor cells are arranged radially around one point, and the size of each phosphor cell (especially the area of the upper surface) is adjusted according to the conversion efficiency of each phosphor. White illumination light is generated by mixing the fluorescence emitted from each phosphor cell.

  Each phosphor cell may be one in which the phosphor is dispersed inside the sealing material, or may be one in which the phosphor is solidified. The sealing material of the light emitting unit 4 is, for example, a resin material such as a glass material (inorganic glass or organic-inorganic hybrid glass) or a silicone resin. The sealing material is preferably highly transparent, and when the laser beam has a high output, a material having high heat resistance is preferable.

  FIG. 4 is a side sectional view showing the configuration of the light emitting unit 4. As shown in FIGS. 3 and 4, partition walls 12 are formed at the boundaries between different types of phosphor cells. The partition wall 12 blocks light transmission and includes a metal having a high reflectance. Examples of the metal include Al and Ag. The partition wall 12 is thermally connected to the support substrate 8, and by forming the support substrate 8 and the partition wall 12 from a material having high thermal conductivity, an effect of releasing the heat of the phosphor of the light emitting unit 4 can be obtained. .

(Movement mechanism of light emitting unit 4)
The support substrate 8 is movable along a rail 9 disposed on the surface of the metal base 7. Therefore, the light emitting unit 4 disposed on the support substrate 8 is also movable. Since the optical path of the laser beam emitted from the laser element 2 is fixed with respect to the reflector 5, the relative positional relationship between the laser beam spot and the light emitting unit 4 can be changed by moving the support substrate 8. .

  As shown in FIG. 3, the light emitting unit 4 includes three phosphor cells (a red phosphor cell 4R, a green phosphor cell 4G, and a blue phosphor cell 4B) arranged adjacent to each other on the same substrate. The laser light is irradiated as a spot 11 to the array of these three phosphor cells. In other words, the above three types of phosphor cells are arranged in the same in-plane direction, and each phosphor cell is directly irradiated with laser light (without passing through other phosphor cells). The

  By moving the light emitting unit 4, the position of the spot 11 in the light emitting unit 4 is changed, and the ratio of the laser light applied to each phosphor cell with respect to the entire amount of laser light forming the spot 11 is changed. As a result, the amount of fluorescence emitted from each phosphor cell changes, and the chromaticity of the illumination light that is a mixture of these fluorescence changes.

(Specific examples of phosphors)
The kind of fluorescent substance contained in the light emission part 4 is not limited. As phosphors of the light emitting section 4, YAG phosphors, oxynitride phosphors (for example, sialon phosphors), III-V compound semiconductor nanoparticle phosphors (for example, indium phosphorus: InP), nitride phosphors, etc. Can be used. In addition, when a high output (and / or light density) excitation light source such as a laser element is used, it is optimal that the phosphor has high heat resistance against laser light.

  In addition, the law stipulates that the illumination light of the headlamp must be white having a predetermined range of chromaticity. For this reason, the light emitting unit 4 includes a phosphor cell selected so that the illumination light is white.

  For example, as described above, when a red phosphor cell, a green phosphor cell, and a blue phosphor cell are included in the light emitting unit 4 and irradiated with near-ultraviolet (for example, 405 nm) laser light, white light is generated.

In this case, as the red phosphor, Eu-activated CaAlSiN ₃ or Eu-activated (Sr, Ca) AlSiN ₃ can be used.

Further, as the green phosphor, a β sialon phosphor activated with Eu, an α sialon phosphor activated with Ce, or Ba ₃ Si ₆ O ₁₂ N ₂ activated with Eu can be used.

Further, as a blue phosphor, a JEM phosphor activated with Ce, BaMgAl ₁₀ O ₁₇ activated with Eu, or (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ activated with Eu may be used. it can.

  Two types of phosphor cells may be used. For example, the light emitting unit 4 including a blue phosphor cell and a yellow phosphor cell may be realized. In the case of irradiating near-ultraviolet laser light, the above-described phosphor can be used for the blue phosphor, and for example, an α-sialon phosphor activated with Eu can be used for the yellow phosphor.

  However, when the present invention is realized as an illumination device other than the headlamp, the illumination light does not necessarily have to be white, and the combination of the laser light and the phosphor is not limited to the above.

(Reflector 5)
The reflector 5 reflects the fluorescence generated by the light emitting unit 4 and forms a light beam (illumination light) that travels within a predetermined solid angle. That is, the reflector 5 reflects the emitted light emitted from the light emitting unit 4 and projects it to the outside. The reflector 5 may be, for example, a member having a metal thin film formed on the surface thereof or a metal member.

  The reflector 5 has at least a part of a partial curved surface obtained by cutting a curved surface (parabolic curved surface) formed by rotating the parabola with the axis of symmetry of the parabola as a rotational axis by a plane including the rotational axis. It is included in the reflective surface.

  However, the reflector 5 is not limited to the one including a parabolic curved surface, and may be an elliptical mirror or a spherical mirror. That is, the reflector 5 reflects at least a part of a partial curved surface obtained by cutting a curved surface formed by rotating a circle or an ellipse around the axis of symmetry as a rotational axis along a plane including the rotational axis. It may be included in the surface.

  The reflector 5 having such a shape is disposed at a position covering the upper surface of the light emitting unit 4. The upper surface of the light emitting unit 4 is a surface having a portion facing the reflecting surface of the reflector 5.

  The laser element 2 is disposed outside the reflector 5, and the reflector 5 is formed with a window portion 6 that transmits or passes laser light. The window 6 may be an opening or may include a transparent member that can transmit laser light. For example, a transparent member having a filter that transmits laser light and reflects fluorescence from the light emitting section 4 may be provided as the window section 6. In this configuration, the fluorescence of the light emitting unit 4 can be prevented from leaking from the window unit 6.

  When providing a plurality of laser elements 2, one window portion 6 may be provided common to the plurality of laser elements 2, or a plurality of window portions 6 corresponding to each laser element 2 may be provided. May be.

(Metal base 7)
The metal base 7 has a surface (opposing surface) facing the reflecting surface of the reflector 5 and supports the light emitting unit 4 and the support substrate 8 on the facing surface.

  The metal base 7 is made of metal (copper, iron, aluminum, etc.), and therefore has high thermal conductivity, and can efficiently dissipate heat generated by the light emitting unit 4.

  Moreover, it is preferable that the opposing surface of the metal base 7 functions as a reflective surface. When the facing surface is a reflecting surface, the laser light incident from the upper surface of the light emitting unit 4 is converted into fluorescence, and then reflected by the reflecting surface and can be directed to the reflector 5.

  In addition, in this embodiment, although the metal base 7 is comprised with the metal, it is not limited to what consists of metals, You may comprise with the member containing substances (glass, sapphire, etc.) with high heat conductivity other than a metal. .

(Support substrate 8)
As described above, the support substrate 8 is a support member that supports the light emitting unit 4, and moves the light emitting unit 4 relative to the laser beam spot 11.

  The support substrate 8 is movable along a pair of rails 9, and as shown in FIG. 2B, a sandwiching portion having a U-shaped cross section for sandwiching a part of the rail 9 is provided on the support substrate. 8 at the edge. With this configuration, the support substrate 8 is unlikely to come off the rail 9.

  The support substrate 8 is made of metal (copper, iron, aluminum, etc.), and the surface of the support substrate 8 preferably functions as a reflective surface.

  However, in the case where an opening is provided in the metal base 7 and laser light is irradiated from the bottom surface of the light emitting unit 4 through the opening and fluorescence is emitted from the upper surface side of the light emitting unit 4, the support substrate 8 is made transparent. It is set as a member.

(Rail 9)
The rail 9 is a member for moving the support substrate 8 on the opposing surface of the metal base 7. Instead of the rail 9, a groove may be formed on the opposing surface of the metal base 7, and the support substrate 8 may be moved along the groove.

  Further, it is not always necessary to move the support substrate 8 linearly, it may be moved along a curve, or may be rotated. In addition, a drive mechanism for moving the support substrate 8 may be provided, and the headlamp 1 manufacturer may manually move the support substrate 8. In other words, the spot changing mechanism of the present embodiment only needs to be able to change the relative position of the light emitting unit 4 with respect to the laser beam spot 11 (more specifically, the relative position of each phosphor cell with respect to the spot 11). .

(Modification example of the light emitting unit 4)
The overall shape of the light emitting unit 4 is not particularly limited, and may be a rectangular parallelepiped or a cylindrical shape, and the size of the light emitting unit 4 is not particularly limited. Further, the shape, size and arrangement of each phosphor cell are not particularly limited.

  FIG. 5 is a top view showing a modified example of the light emitting unit 4. As shown in FIG. 5, the red phosphor cell 4R, the green phosphor cell 4G, and the blue phosphor cell 4B may be arranged in a line.

  The red phosphor absorbs the fluorescence emitted by the blue phosphor more efficiently than the fluorescence emitted by the green phosphor, and multistage excitation is likely to occur when the red phosphor cell 4R and the blue phosphor cell 4B are brought close to each other. .

  Therefore, the red phosphor cell 4R and the blue phosphor cell 4B that are likely to cause multistage excitation are separated from each other (that is, the green phosphor cell 4G is disposed between them) to suppress multistage excitation. Can do.

  In addition, a phosphor cell containing a phosphor having the highest temperature resistance is arranged in the center of the spot 11 having the highest excitation power density, and a phosphor cell containing a phosphor having a low temperature tolerance is arranged on both sides thereof. Also good. That is, the phosphor cell including the phosphor having the highest temperature resistance among the plurality of types of phosphor cells may be arranged at the position closest to the center of the spot 11. A phosphor with high temperature resistance is, for example, a phosphor with low temperature quenching or a phosphor that is not easily deteriorated by heat. With this configuration, the light emission efficiency of the light emitting unit 4 can be increased.

(Operational effect of the headlamp 1)
In the headlamp 1, the relative positional relationship between the plurality of phosphor cells included in the light emitting unit 4 and the spot 11 of the laser light as the excitation light can be changed. By changing this relative positional relationship, the area where the excitation light strikes each phosphor cell changes, and as a result, the chromaticity of the illumination light changes.

  Therefore, it is possible to easily adjust the chromaticity of the illumination light of the headlamp 1 to a desired one after the headlamp 1 is manufactured. This adjustment may be performed by manually moving the light emitting unit 4. Further, if the light emitting unit 4 is moved by a driving device (such as an electric motor), the user can easily adjust the illumination light of the headlamp 1 to a desired color.

  Even in a method of manufacturing a light emitting unit by mixing a plurality of types of phosphors that emit different fluorescence, chromaticity can be adjusted to some extent. However, in this case, it is difficult to adjust the chromaticity after manufacturing the light emitting part.

  In addition, when a plurality of types of phosphors are mixed, it is difficult to mix these phosphors uniformly. Further, even in the same type of phosphor, the particle size of the phosphor is not the same, and there is a particle size distribution. Therefore, even if a plurality of light emitting units are manufactured by the same manufacturing method, the chromaticities of fluorescence obtained by irradiating the manufactured light emitting units with excitation light are likely to be different from each other, and illumination with a desired chromaticity It is difficult to obtain light stably.

  On the other hand, in the headlamp 1, phosphor cells are formed for the phosphors of different colors, and by changing the irradiation area of the excitation light irradiated to the plurality of types of phosphor cells. The chromaticity is adjusted.

  Therefore, there is almost no influence of non-uniformity that occurs when a plurality of types of phosphors are mixed, and the chromaticity can be easily adjusted simply by changing the irradiation position of the excitation light on the light emitting unit 4.

(Example of changing headlamp 1)
In the above-described headlamp 1, the light emitting unit 4 is moved, but the laser element 2 that is an excitation light source may be moved. For example, the optical axis of the laser beam may be changed by changing the angle of the laser element 2, and as a result, the relative position between the spot 11 and the light emitting unit 4 may be changed. In this case, the mechanism for adjusting the angle of the laser element 2 is a spot changing mechanism.

  However, when the spot 11 is moved, the position of the light emitting point changes, and the light emitting point may not be located at the focal position of the reflector 5. Therefore, it is preferable to move the light emitting unit 4 in consideration of efficient light distribution control.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. In addition, about the member similar to Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  FIG. 6 is a cross-sectional view showing the configuration of the headlamp 20 according to the present embodiment. The headlamp 20 is not provided with a mechanism (the support substrate 8 and the rail 9) for moving the light emitting unit 4, and the illumination light is changed by changing the size of the spot 11 of the laser light applied to the light emitting unit 4. Change the chromaticity of. In order to change the size of the spot 11, the headlamp 20 includes a lens position changing mechanism (spot changing mechanism) 21 that changes the position of the lens 3.

  The lens position changing mechanism 21 moves the lens 3 along the optical axis of the laser light emitted from the laser element 2 to change the distance between the laser element 2 and the lens 3. Accordingly, the size of the laser beam spot 11 in the light emitting unit 4 can be changed.

  The light emitting unit 4 shown in FIG. 7 can be suitably used as the light emitting unit 4 of the headlamp 20. FIG. 7 is a top view showing a configuration of the light emitting unit 4 that can be suitably used for the headlamp 20. In the light emitting unit 4 shown in FIG. 7, the green phosphor cell 4G is arranged along the outer periphery of the cylindrical red phosphor cell 4R, and the blue phosphor cell 4B is arranged on the outer side.

  The center of the spot 11 coincides with the center of the upper surface of the red phosphor cell 4R, and by changing the size of the spot 11, the amount of laser light irradiated mainly on the blue phosphor cell 4B is changed. As a result, the chromaticity of the illumination light can be adjusted. As described above, in the headlamp 20, the chromaticity of the illumination light can be adjusted by changing the position of the lens 3 without changing the position of the spot 11 in the light emitting unit 4.

  Further, as shown in FIG. 7, the multistage excitation can be suppressed by separating the red phosphor and the blue phosphor that are likely to cause multistage excitation.

  In addition, a phosphor that is less susceptible to temperature quenching is disposed at the center of the spot 11, and a phosphor that is susceptible to temperature quenching is disposed at a position away from the center, thereby suppressing temperature quenching and increasing the luminous efficiency of the light emitting unit 4. Can be increased.

  The green phosphor cell 4G and the blue phosphor cell 4B are only required to be disposed at least partly around the red phosphor cell 4R, and each of the green phosphor cells 4G does not necessarily need to surround the red phosphor cell 4R in a ring shape. Absent.

  Further, the light emitting unit 4 shown in FIGS. 3 and 5 may be used as the light emitting unit 4 of the headlamp 20. However, when the light emitting unit 4 shown in FIG. 3 is used, the center of the spot 11 is appropriately set so that the chromaticity of the illumination light changes according to the size of the spot 11.

(Modification example of the headlamp 20)
The reflector 5 may have a closed circular opening. In this case, it is only necessary to irradiate the light emitting unit 4 disposed at a substantially focal position of the reflector 5 with the laser light through a laser light incident port formed near the apex of the reflector 5.

  The size of the laser beam spot 11 can be changed by moving the lens 3 disposed in the vicinity of the laser beam entrance by the lens position changing mechanism 21.

[Embodiment 3]
The following will describe another embodiment of the present invention with reference to FIGS. In addition, about the member similar to Embodiment 1-2, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  FIG. 8 is a top view showing still another configuration of the light emitting unit 4. In the light emitting unit 4 shown in FIG. 8, phosphor cells 4R, 4G, and 4B of three colors of R, G, and B are arranged in a matrix in the order of R, G, and B. In this way, the color unevenness of the illumination light can be reduced by finely partitioning the light emitting unit 4 with the phosphor cells of the respective colors. The light emitting unit 4 can be applied to both the headlamp 1 and the headlamp 20.

  Moreover, it is preferable that the partition 12 is formed between each phosphor cell similarly to the above-mentioned embodiment. Moreover, since the particle size of the phosphor is about 10 μm, the size of each phosphor cell is made larger.

When the diameter of the spot 11 is defined by 1 / e ² of the peak intensity of the excitation light, the size of the phosphor cell is 1/30 or less of the diameter of the spot 11 in the case of three colors, and the spot 11 in the case of two colors. More preferably, it is 1/20 or less of the diameter. That is, the plurality of types of phosphor cells have a size that is equal to or smaller than a reference value defined with reference to the size of the spot 11. With this configuration, it is possible to effectively reduce color unevenness caused by arranging a plurality of color phosphor cells.

(Manufacturing method of the light emission part 4)
Next, an example of a method for manufacturing the light emitting unit 4 will be described. The manufacturing method described here can be applied not only to the light emitting unit 4 shown in FIG. 8 but also to the light emitting unit 4 of FIGS. 3 and 5.

<Photolithography method>
First, a method for patterning a phosphor by photolithography will be described.

  FIG. 9 is a diagram for explaining a method of patterning a phosphor by photolithography. In this method, first, a resist layer 32 is formed on a substrate 31. The substrate 31 may be a support substrate 8 (a reflective plate or a transparent substrate) or a metal base 7.

  Then, the resist layer 32 in the region 33 where the red phosphor cell 4R is to be formed is removed by exposure and development using a photomask.

  Next, the red phosphor cell 4R is formed on the substrate 31 by deposition of the red phosphor by electrophoresis or application of the red phosphor using a dispenser.

  Thereafter, by removing the resist layer 32, the substrate 31 in which the red phosphor cell 4R is formed in the desired region 33 is obtained.

  Similar processing is performed for the green phosphor cell 4G and the blue phosphor cell 4B.

<Screen printing method>
A screen mask is prepared in advance, and a target phosphor layer is formed on the substrate 31 through the opening of the screen mask.

<Inkjet method>
A phosphor is applied onto the substrate 31 from an inkjet head. In this method, phosphors can be applied directly without requiring a mask, and the amount of phosphors to be used can be suppressed.

<Method for Forming Partition Wall 12>
The partition wall 12 can be formed by, for example, a photolithography method. FIG. 10 is a diagram for explaining a method of forming the partition wall 12.

  First, a resist layer 32 is formed on the substrate 31.

  Then, using a photomask, exposure and development are performed only on the portion where the partition wall 12 is formed.

  Next, portions other than the resist layer 32 are removed by etching.

  Further, the resist layer 32 is completely removed with a solvent.

  Note that the barrier ribs 12 are formed on the substrate 31 first, and then the phosphor layer is formed.

[Embodiment 4]
The following will describe another embodiment of the present invention with reference to FIGS. In addition, about the member similar to Embodiment 1-3, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the present embodiment, blue (450 nm) or so-called blue laser light having a peak wavelength in the wavelength range of 440 nm to 490 nm is used as excitation light. On the other hand, the light emitting unit 4 includes a yellow phosphor (or green and red phosphors). Part of the blue excitation light is emitted to the outside as illumination light, and white illumination light is generated by mixing the blue excitation light and yellow (or green and red) fluorescence. Other configurations are the same as those of the headlamp 1 and the headlamp 20.

  FIG. 11 is a top view showing a configuration of the light emitting unit 4 applied to the present embodiment. As shown in FIG. 11, the light emitting unit 4 in the present embodiment is a set of a plurality of light emitting units 41 arranged at intervals. Each light emitting unit 41 includes a yellow phosphor (or green and red phosphor). The number, arrangement, and interval of the light emitting units 41 are not particularly limited.

  When the light emitting unit 41 is applied to the headlamp 1, the light emitting unit 41 may be formed on the support substrate 8. When the light emitting unit 41 is applied to the headlamp 20, the light emitting unit 41 may be directly formed on the metal base 7, or the light emitting unit 41 is formed on another substrate and the substrate is formed on the metal base 7. You may arrange in.

  When blue excitation light and yellow fluorescence are used, YAG phosphor or Eu-activated α sialon phosphor can be used as the yellow phosphor.

In addition, when blue excitation light and green and red phosphors are used, a β sialon phosphor activated with Eu as a green phosphor, Ca ₃ Sc ₂ Si ₃ O ₁₂ activated with Ce, and CaSc activated with Ce. ₂ O ₄ or Ba ₃ Si ₆ O ₁₂ N ₂ activated with Eu can be used. Further, as the red phosphor, CaAlSiN ₃ activated with Eu and (Sr, Ca) AlSiN ₃ activated with Eu can be used.

(Principle of chromaticity adjustment)
When using the light emission part 41, a part of excitation light is utilized as illumination light. By changing the relative positions of the plurality of light emitting units 41 and the spots 11, the ratio between the excitation light converted into fluorescence and the excitation light emitted outside as illumination light without being converted into fluorescence changes. As a result, the chromaticity of the illumination light changes.

(Realization of eye safe)
The blue excitation light applied to the light emitting unit 41 may be light emitted from an LED or laser light emitted from a laser element.

  When using laser light as blue excitation light, it is preferable to scatter the laser light from the viewpoint of eye-safety. FIG. 12 is a cross-sectional view showing a configuration in which the scattering portion 42 is provided around the light emitting portion 41.

The scattering unit 42 includes fine particles therein, and scatters the laser light by irregularly reflecting the received laser light by the fine particles. The base material of the scattering part 42 can be comprised with resin materials, such as glass material (inorganic glass, organic-inorganic hybrid glass), a silicone resin, for example. Low melting glass may be used as the glass material. For example, the scattering portion 42 may be made of inorganic glass containing TiO ₂ fine particles at a weight ratio of 30%.

  Part of the laser light incident on the scattering unit 42 excites the phosphor of the light emitting unit 41 as excitation light, and the other part exits from the scattering unit 42 and becomes illumination light. Since the laser light that has not excited the phosphor is scattered by the scattering portion 42, its coherency is reduced, and the size of the light emitting portion that is a point light source is apparently enlarged. As a result, eye safe can be realized.

  It is not always necessary to cover the light emitting part 41 with the scattering part 42, and the scattering part 42 may be formed between the plurality of light emitting parts 41.

  Further, it is not always necessary to arrange a member that scatters laser light in the vicinity of the light emitting portion 41, and a diffuser plate may be provided in the opening of the reflector 5. By diffusing laser light with this diffusion plate, the light density on the diffusion plate can be lowered to a value safe for the human eye. Therefore, when the headlamp 1 is viewed from the outside, the diffuser plate can function as a safe “apparent light source” having a low light density.

  The diffusion plate can be made of a light-transmitting material such as polycarbonate, glass, or acrylic.

  Further, by using such a diffusion plate and / or the scattering portion 42, an effect of reducing color unevenness caused by using a phosphor cell containing phosphors of a plurality of colors can be obtained. Therefore, you may apply a diffuser plate and / or the scattering part 42 to the headlamp 1 and the headlamp 20 provided with the light emission part 4 shown in FIG. 3 or FIG.

(Method for manufacturing light emitting unit 41)
Next, the manufacturing method of the light emission part 41 is demonstrated. FIG. 13 is a diagram for explaining a method of manufacturing the light emitting unit 41. First, the phosphor layer 34 is formed on the substrate 31.

  Next, a resist layer 32 is formed on the phosphor layer 34. Then, the resist layer 32 in the region where the light emitting portion 41 is not formed is removed by exposing and developing using a photomask.

  Then, after etching the phosphor layer 34 not masked by the resist layer 32, the resist layer 32 is entirely removed.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be applied to a light emitting device, a lighting device, particularly a headlamp for a vehicle or the like, and can adjust the chromaticity of emitted light.

1 Headlamp (light emitting device, lighting device, vehicle headlamp)
2 Laser element (excitation light source)
4 Light Emitting Unit 4B Blue Phosphor Cell 4G Green Phosphor Cell 4R Red Phosphor Cell 8 Support Substrate (Spot Change Mechanism)
9 rails (spot changing mechanism)
11 Spot 12 Bulkhead 20 Headlamp (light emitting device, lighting device, vehicle headlamp)
21 Lens position change mechanism (spot change mechanism)
41 Light emitting part 42 Scattering part

Claims (13)

An excitation light source that emits excitation light;
A first phosphor cell that includes a first phosphor that emits fluorescence of a first color in response to excitation light emitted from the excitation light source; and a second that is different from the first color in response to the excitation light. A light emitting unit including a second phosphor cell including a second phosphor that emits color fluorescence,
The excitation light is irradiated as a spot to the light emitting unit,
A light-emitting device, further comprising a spot changing mechanism that makes it possible to change the position or size of the spot in the light-emitting unit.   The first phosphor cell and the second phosphor cell are arranged in the same in-plane direction, and the excitation light is irradiated to the first and second phosphor cells. The light emitting device according to claim 1. The light emitting unit further includes a third phosphor cell including a third phosphor that emits fluorescence of a third color different from the first and second colors,
The first phosphor absorbs the fluorescence emitted by the second phosphor more efficiently than the fluorescence emitted by the third phosphor,
The light emitting device according to claim 1 or 2, wherein the third phosphor cell is disposed between the first phosphor cell and the second phosphor cell.   The phosphor cell including a phosphor having the highest temperature resistance among the plurality of types of phosphor cells is disposed at a position closest to the center of the spot. Light emitting device. The second phosphor cell is disposed on at least a part of the periphery of the first phosphor cell,
The light-emitting device according to claim 1, wherein the spot changing mechanism changes a size of the spot.   The light emitting device according to claim 1, wherein the plurality of types of phosphor cells are arranged in a matrix.   The light emitting device according to claim 6, wherein the plurality of types of phosphor cells have a size equal to or smaller than a reference value defined with reference to the size of the spot.   The light emitting device according to any one of claims 1 to 7, wherein a partition wall that prevents transmission and absorption of light is provided between the phosphor cells of different types.   The light emitting device according to claim 8, wherein the partition wall includes a material having high thermal conductivity. An excitation light source that emits excitation light;
A light emitting unit that emits fluorescence in response to excitation light emitted from the excitation light source,
In addition to the fluorescence, a part of the excitation light is emitted to the outside as emitted light,
The excitation light is irradiated as a spot to the light emitting unit,
A light-emitting device, further comprising a spot changing mechanism capable of changing a relative positional relationship between the light-emitting unit and the spot or a size of the spot.   The light emitting device according to claim 10, wherein the light emitting unit includes a plurality of light emitting units arranged at intervals.   A vehicle headlamp comprising the light-emitting device according to claim 1.   An illuminating device comprising the light emitting device according to claim 1.

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