JP6125776B2 - Floodlight device - Google Patents

Description

  The present invention relates to a light projecting device including a fluorescent member irradiated with excitation light emitted from a semiconductor light emitting element.

  Patent Document 1 discloses a semiconductor light emitting element that emits light, a condensing member that condenses light emitted from the semiconductor light emitting element and irradiates the phosphor, and predetermined light projection of light converted in wavelength by the phosphor A vehicular lamp (light projecting device) including a light projecting member that projects light to a region is disclosed.

  This vehicular lamp can generate high-luminance light from the phosphor by exciting the phosphor particles with a high light density by reducing the irradiation area of the excitation light irradiated on the phosphor. This high luminance light is projected by the light projecting member, and a light projection region with high illuminance can be formed.

JP 2005-150041 A

  However, if the irradiation spot of the excitation light irradiated to the phosphor is further reduced in order to increase the luminance, the particle size of the phosphor particles relative to the irradiation spot becomes relatively large, and multiple types of phosphors that generate fluorescence of different colors When particles are used, there is a problem that color unevenness occurs.

  The present invention has been made to solve the above-described problems, and provides a light projecting device capable of obtaining a light projecting region having high illuminance from a light source having high luminance and suppressing occurrence of color unevenness. With the goal.

  In order to achieve the above object, the present invention is different from the semiconductor light emitting device that emits light, the light collecting member that collects light from the semiconductor light emitting device and emits spot-like excitation light, and the excitation light. A plurality of types of phosphor particles that are converted into color fluorescence, and a fluorescent member that emits fluorescence from a spot-like light emission spot corresponding to the excitation light, and the fluorescence emitted from the fluorescent member is projected onto a predetermined region In a light projecting device comprising a light projecting member, the area of a circle derived based on the median diameter of the phosphor particles in the light emitting spot is 50% or more with respect to the maximum light intensity of the fluorescence emitted from the light emitting spot. It is characterized by being 0.5% or less of the light emitting area having the light intensity of.

  According to this configuration, fluorescence of different colors is emitted from the phosphor particles from the phosphor spots by the excitation light emitted from the light collecting member. At this time, the area of the circle derived based on the median diameter of the phosphor particles in the light emission spot is 0.5 of the light emission area having a light intensity of 50% or more with respect to the maximum light intensity of the fluorescence emitted from the light emission spot. % Or less. As a result, the ratio of the phosphor particles per one emission spot to the emission spot that emits fluorescence becomes relatively small, and color unevenness of the fluorescence emitted from the emission spot is suppressed.

  According to the present invention, in the light projecting device having the above-described configuration, a plurality of spot-like excitation lights are emitted from the light collecting member, and the light emission spots corresponding to the respective excitation lights overlap each other. According to this configuration, by emitting a plurality of excitation lights, a plurality of light emission spots can be obtained, and the brightness of the light is increased. Further, even in the overlapping light emission spots, the area of the circle derived based on the median diameter of the phosphor particles in each light emission spot has a light intensity of 50% or more with respect to the maximum light intensity of the fluorescence emitted from each light emission spot. It becomes 0.5% or less of the area of the light emission spot. Thereby, the phosphor particles can be excited at a high light density in the overlapping light emission spots, and color unevenness of the fluorescence emitted from each light emission spot is suppressed.

  According to the present invention, in the light projecting device configured as described above, the fluorescent member has the light emitting spot formed on a surface irradiated with the excitation light. According to this configuration, since the scattering of excitation light and fluorescence inside the fluorescent member can be suppressed, the light emission spot can be brought close to the area of the irradiation region.

  According to the present invention, in the light projecting device having the above-described configuration, the semiconductor light emitting element is a semiconductor laser element that emits laser light. According to this configuration, the fluorescent member can be irradiated with excitation light having a high light density in a smaller irradiation region.

  According to the present invention, the phosphor particles that are converted into fluorescence of different colors by the excitation light emitted from the light collecting member are excited to emit fluorescence of a predetermined wavelength from the light emitting spot. The fluorescence emitted from the light emitting spot is projected onto a predetermined area by the light projecting member. At this time, the area of the circle derived based on the median diameter of the phosphor particles in the light emission spot is 0 with respect to the light emission area having a light intensity of 50% or more with respect to the maximum light intensity of the fluorescence emitted from the light emission spot. By setting the ratio to 0.5% or less, the ratio of phosphor particles per one light emitting spot emitting fluorescence is relatively small. Thereby, generation | occurrence | production of the color nonuniformity of the fluorescence light-emitted from a light emission spot can be suppressed. Therefore, even in the case where the irradiation area of the excitation light irradiated to the fluorescent member is reduced to excite the phosphor particles with a high light density and the brightness of the light emitting spot is increased, Occurrence of color unevenness can be suppressed.

Side surface sectional drawing of the light projection apparatus which concerns on 1st Embodiment of this invention. The perspective view which showed the state which irradiated the laser beam to the fluorescent member of the light projection apparatus which concerns on 1st Embodiment of this invention. The enlarged plan view which shows the fluorescent substance particle contained in the fluorescent member of the light projection apparatus which concerns on 1st Embodiment of this invention. The figure explaining the light emission area of the fluorescence radiate | emitted from the fluorescent member of the light projection apparatus which concerns on 1st Embodiment of this invention. Side surface sectional drawing of the light projection member of the light projector which concerns on 1st Embodiment of this invention. The figure for explaining the experiment which was done in order to evaluate the color irregularity of the floodlight Diagram showing the relationship between the median diameter of phosphor particles and the occupation ratio contained in the light emission spot A diagram showing the relationship between the occupancy ratio of phosphor particles contained in the light emission spot and the standard deviation of the color temperature distribution Side surface sectional drawing of the light projection apparatus which concerns on 2nd Embodiment of this invention. The figure explaining the light emission area of the fluorescence radiate | emitted from the fluorescent member of the light projection apparatus which concerns on 2nd Embodiment of this invention. Side surface sectional drawing of the light projection apparatus which concerns on 3rd Embodiment of this invention.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of the light projecting device according to the first embodiment. The floodlight device 1 is used as a headlamp that illuminates the front of a car or the like, for example. The light projecting device 1 includes a semiconductor light emitting element 20, a light collecting member 21, a reflecting plate 29, a fluorescent member 22, a light projecting member 23, a mounting member 24, and a filter member 25.

  The light emitted from the semiconductor light emitting element 20 is collected by the light collecting member 21 and emits spot-like excitation light. The optical path of the excitation light is changed by the reflection plate 29 and enters the light projecting member 23. The incident excitation light is applied to the fluorescent member 22, and the fluorescent member 22 excites the fluorescent light and exits from the light emitting spot 22b. The fluorescence is projected onto a predetermined light projecting area by the light projecting member 23.

  The semiconductor light emitting element 20 is a semiconductor laser element, and emits near-ultraviolet laser light having an emission peak in a wavelength region of 350 nm to 420 nm. The semiconductor light emitting element 20 is not limited to a semiconductor laser element, and a light emitting diode element may be used. However, the semiconductor laser element can irradiate the fluorescent member 22 with higher light density excitation light in a smaller irradiation region than the light emitting diode element. Therefore, it is preferable to use a semiconductor laser element.

  The condensing member 21 condenses the laser light from the semiconductor light emitting element 20 and emits spot-like excitation light. At this time, the condensing member 21 includes an optical fiber 21a which is a light guiding member, and lenses 21b and 21c arranged at both ends of the optical fiber. The optical fiber 21 a guides the laser light emitted from the semiconductor light emitting element 20. The optical fiber 21a has a two-layer structure in which an intermediate core is covered with a clad having a refractive index lower than that of the core. As a result, the laser light incident from the incident end passes through the optical fiber 21a and is emitted from the emission end that is the other end. When the optical fiber 21a is used, the distance between the semiconductor light emitting element 20 and the fluorescent member 22 can be freely set. For this reason, the freedom degree of design becomes large. The fluorescent member 22 may be irradiated with spot-like excitation light using a mirror or a lens instead of the optical fiber 21a.

  The lens 21b is an optical member that optically couples the semiconductor light emitting element 20 and the incident end of the optical fiber 21a. The laser light emitted from the semiconductor light emitting element 20 enters the incident end of the optical fiber 21a. The spot diameter and incident angle of excitation light incident on the optical fiber 21 can be controlled through the lens 21b. The lens 21c emits laser light emitted from the emission end of the optical fiber 21a as spot-like excitation light. By passing through the lens 21c, the spot diameter and the incident angle of the excitation light reflected by the reflecting plate 29 and incident on the fluorescent member 22 can be controlled.

  The reflector 29 reflects the excitation light from the light collecting member 21 to the fluorescent member 22. Further, the light projecting member 23 is provided with a window portion 23b. The excitation light reflected by the reflecting plate 29 enters the light projecting member 23 through the window portion 23b. The window portion 23b may be opened or may include a transparent member that can transmit excitation light. Moreover, the window part 23b should just be provided in the range which excitation light passes or permeate | transmits. Note that the fluorescent member 22 may be directly or indirectly irradiated with the excitation light from the lens 21c without using the reflection plate 29.

  The fluorescent member 22 converts the excitation light emitted from the light collecting member 21 into fluorescence and emits it. The light projecting member 23 projects the light by reflecting the fluorescence emitted from the fluorescent member 22 in a predetermined direction (A direction). The attachment member 24 has a base portion 24a and an attachment portion 24b. The light projecting member 23 is fixed to the base portion 24a, and the fluorescent member 22 is attached to the attachment portion 24b. The filter member 25 absorbs or reflects the excitation light emitted from the light collecting member 21 to shield it, and transmits the fluorescence converted in wavelength by the fluorescent member 22 in the A direction. Thereby, it is possible to prevent the excitation light from leaking outside the light projecting member 23. Note that when the excitation light is used as part of the illumination light, the filter member 25 may be omitted.

  FIG. 2 is a perspective view showing a state in which the fluorescent member 22 is irradiated with laser light, and FIG. 3 is an enlarged plan view showing the fluorescent particles contained in the fluorescent member 22 and showing the fluorescent member 22 from above. The fluorescent member 22 has an irradiation surface 22a on which laser light is irradiated. The central portion of the irradiation surface 22a is irradiated with spot-like excitation light condensed through the condensing member 21.

The fluorescent member 22 is formed by dispersing phosphor particles 29 inside a sealing material (not shown). The phosphor particles 29 may be formed by solidifying. The fluorescent member 22 is formed using, for example, two types of phosphor particles 29 that convert blue-violet light (excitation light) into blue light and yellow light and emit the light. Examples of the phosphor particles 29 that convert blue-violet light into blue light include BaMgAl ₁₀ O ₁₇ : Eu and (Sr, Ca, Ba, Mg) 10 (PO ₄ ) 6Cl ₂ : Eu. Examples of the phosphor particles 29 that convert blue-violet light into yellow light include Ca-αSiAlON: Eu. For example, a resin material such as a glass material or a silicone resin is used as the sealing material. As the glass material, low melting glass can be used. The sealing material is preferably highly transparent. In addition, when the laser light emitted from the semiconductor light emitting element 20 has a high output, those having high heat resistance and light resistance are preferable.

  White light is obtained by mixing the fluorescence of the blue light and the yellow light emitted from the fluorescent member 22. The phosphor particles 29 included in the phosphor member 22 only need to include a plurality of phosphor particles 29 that convert excitation light into fluorescence of different colors, such as the center wavelength of the laser light emitted from the semiconductor light emitting element 20, The kind of phosphor particles constituting the fluorescent member 22 can be changed as appropriate.

For example, the fluorescent member 22 can be formed by using three types of phosphor particles that convert blue-violet light (excitation light) into red light, green light, and blue light and emit the light. Examples of the phosphor particles 29 that convert blue-violet light into red light include CaAlSiN ₃ : Eu. Examples of the phosphor particles 29 that convert blue-violet light into green light include β-SiAlON: Eu. Examples of the phosphor particles 29 that convert blue-violet light into blue light include BaMgAl ₁₀ O ₁₇ : Eu and (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu. Red light is light having a center wavelength of about 640 nm, for example, and green light is light having a center wavelength of about 520 nm, for example. Blue light is light having a center wavelength of about 450 nm, for example. Further, the excitation light is not limited to blue-violet light but may be blue light. In this case, for example, the fluorescent member 22 can be formed using two types of phosphor particles that are converted from blue light (excitation light) into red light and green light, respectively. Examples of the phosphor particles 29 that convert blue light into red light include CaAlSiN ₃ : Eu. Examples of the phosphor particles 29 that convert blue light into green light include β-SiAlON: Eu.

  In addition, an example in which the excitation light source (semiconductor light emitting element 20) and the fluorescent member 22 are configured to emit white light has been described. However, the excitation light source and the fluorescent member are configured to emit light other than white light. May be.

  Further, it is desirable that the fluorescent member 22 contains phosphor particles 29 at a high density. Thereby, the absorption rate of the excitation light in the fluorescent member 22 can be increased. Therefore, the excitation light can be efficiently converted into fluorescence, and the thickness of the fluorescent member 22 can be reduced. For this reason, the heat dissipation of the fluorescent member 22 is improved, and a high-intensity light source (light emission spot 22b) is realized by the fluorescent member 22. In addition, since the fluorescent particles 29 are contained in the fluorescent member 22 at a high density, the excitation light incident on the irradiation surface 22a of the fluorescent member 22 is easily converted into fluorescence in the vicinity of the surface of the irradiation surface 22a. Thereby, the irradiation area irradiated with excitation light on the irradiation surface 22a and the light emission spot 22b from which the fluorescence is emitted substantially coincide with each other, and the light emission spot 22b can be suppressed from becoming larger than the irradiation area of the excitation light.

FIG. 4 is a view for explaining the emission area of the fluorescence emitted from the fluorescent member 22. 4 shows a side view of the fluorescent member 22, a middle portion shows a top view of the fluorescent member 22, and a lower portion shows the light intensity distribution on the line of the light emission spot 22b. The fluorescence is emitted from the light emission spot 22b on the irradiation surface 22a. At this time, a light emitting region having a light intensity of 50% or more with respect to the maximum light intensity of the fluorescence emitted from the light emitting spot 22b is defined as an effective light emitting region 22c. Effective light emitting region 22c area ratio r = s / L of median diameter of the phosphor particles 29 in the light-emitting spot 22b (d ₅₀₎ area of a circle which is derived from ^{_{s (s = πd 50 2/}} 4) to the emission area L of Is 0.5% or less. At this time, the derived area ratio r = s / L is referred to as an occupation ratio of the phosphor particles 29 included in the light emission spot 22b. That is, by setting the area ratio r = s / L to 0.5% or less, the occupation ratio occupied by one phosphor particle 29 in the light emission spot 22b becomes relatively small. Thereby, the color unevenness of the fluorescence emitted from the light emission spot 22b can be suppressed.

Here, the median diameter (d ₅₀ ) is a group having a large particle diameter and a group having a small particle diameter when the group of phosphor particles 29 in the light emission spot 22b is divided into two based on the particle diameter. This is the particle size of the phosphor particles 29 when the amount is reached.

  The fluorescent member 22 is disposed in a region including the focal point F23 of the reflecting surface 23a of the light projecting member 23, and the center of the irradiation surface 22a of the fluorescent member 22 substantially coincides with the focal point F23 of the reflecting surface 23a. However, since the spot area (irradiation area) of the excitation light on the irradiation surface 22a has a certain size, the light emitted from the light projecting member 23 is not completely parallel light. For this reason, the light projection area projected by the light projecting member 23 becomes wide, and the central portion of the light projection area becomes dark.

  Therefore, the light projected from the light projecting member 23 can be made closer to parallel light by narrowing the irradiation area of the excitation light on the irradiation surface 22a to reduce the light emission area of the light emission spot 22c. That is, by reducing the excitation light irradiation area and exciting the fluorescent member 22 with a high light density, the light emission spot 22b becomes a light source with higher luminance. At this time, the light projection area of the light projection member 23 is narrowed, but the illuminance at the center of the light projection area is improved. Therefore, it is possible to illuminate the area that needs to be illuminated brighter than other areas by using the light projecting device 1. At this time, color unevenness of parallel light projected from the light projecting member 23 can be suppressed by relatively reducing the occupation ratio of the phosphor particles 29 per one area with respect to the area of the light emitting spot 22b.

In order to bring the light emitted from the light projecting member 23 closer to parallel light, the light emitting area of the effective light emitting region S is preferably 0.1 mm ² or less, and particularly preferably 0.05 mm ² or less. At this time, the median diameter of the phosphor particles 29 in the light emission spot 22b is preferably 18 μm or less.

  FIG. 5 is a side sectional view of the light projecting member 23. The reflecting surface 23a of the light projecting member 23 is disposed so as to face the irradiation surface 22a of the fluorescent member 22, and converts the light from the fluorescent member 22 into parallel light and reflects it in a predetermined direction (A direction). Moreover, the reflective surface 23a is formed so that a part of paraboloid may be included, for example. Specifically, the reflecting surface 23a is a surface that divides the paraboloid by a plane orthogonal to (intersects) the axis connecting the vertex V23 and the focal point F23, and parallel to the axis connecting the vertex V23 and the focal point F23. It is formed in the shape divided by.

  In addition, although shown about the example which formed the reflective surface 23a of the light projection member 23 by a part of paraboloid, you may form the reflective surface 23a by a part of ellipsoid. In this case, the light emitted from the light projecting device 1 can be easily condensed by positioning the fluorescent member 22 at the focal point of the reflecting surface 23a. Further, the reflecting surface 23a may be formed by a multi-reflector composed of a large number of curved surfaces (for example, a parabolic surface) or a free curved surface reflector provided with a large number of fine planes continuously. The light projecting member 23 may include a parabolic mirror having a closed circular opening or a part thereof. Further, a lens may be used for the light projecting member 23. This lens is an optical system that projects fluorescence in a predetermined light projecting direction by transmitting and refracting the fluorescence.

  The light projecting member 23 is fixed to a base portion 24a made of metal, and the base portion 24a is disposed on a substantially central axis of the reflecting surface 23a. The mounting portion 24b has an inclined surface inclined at a predetermined inclination angle α (for example, 0 ° to 30 °) with respect to the central axis of the reflecting surface 23a, and the fluorescent member 22 is disposed on the inclined surface. Further, the upper surface 24c of the base portion 24a is preferably formed so as to have a function of reflecting light. The attachment member 24 is made of a metal having good thermal conductivity such as Al, and has a function of radiating heat generated in the fluorescent member 22. Further, a heat radiating fin (not shown) may be provided on the lower surface of the mounting member 24. Moreover, although the example which provided the light projection member 23 and the attachment member 24 by the separate body was demonstrated, you may form the light projection member 23 and the attachment member 24 integrally.

  In the above-described embodiment, the example in which the fluorescent member 22 is directly attached to the attachment portion 24b has been described. However, when the fluorescent member 22 is formed on a support plate (not shown), the support plate is attached to the attachment portion 24b.

  The filter member 25 is fixed to the light projecting member 23 and the attachment member 24, and covers the opening surface at one end of the light projecting member 23 in the axial direction. The filter member 25 shields the excitation light (near ultraviolet light) from the semiconductor light emitting element 20 by absorption or reflection, and transmits the fluorescence emitted from the fluorescent member 22. As the filter member 25, for example, a glass material such as TY-418 manufactured by Isuzu Seiko Glass Co., Ltd. or L42 manufactured by HOYA Corporation can be used.

  Next, the occupation ratio and color unevenness of the phosphor particles 29 included in the light emission spot 22b of the fluorescent member 22 were evaluated. Here, the diameter of the phosphor particles 29 was measured by a laser diffraction scattering particle distribution measurement method. In the laser diffraction / scattering particle distribution measurement method, the particle diameter is measured from the pattern of diffraction / scattered light when laser light is irradiated onto the particle. At this time, the particle diameter of the spherical particles showing the same diffraction / scattered light pattern is the particle diameter of the object to be measured.

  FIG. 6 is a diagram for explaining evaluation of color unevenness. As shown in FIG. 6, the laser light emitted from the semiconductor light emitting element 20 is condensed by the condensing member 21, irradiated with the excitation light to the fluorescent member 22, and the light is emitted from the light emitting spot 22b. The light emitting spot 22b is disposed at the focal point of the light projecting member 23, and the light projecting member 23 reflects the light from the light emitting spot 22b into parallel light and projects it onto the target 30. The emission wavelength of the laser light was 405 nm. The fluorescent member 22 includes a plurality of phosphor particles 29 that excite fluorescence of different colors of blue and yellow. Thereby, the mixed white light is emitted from the light emission spot 22b.

The phosphor particles 29 included in the phosphor member 22 used BaMgAl ₁₀ O ₁₇ : Eu as the phosphor particles 29 that convert excitation light into blue light. Further, Ca-αSiAlON: Eu was used as the phosphor particles 29 for converting the excitation light into yellow light. In addition, a reflector having a diameter of 20 mm was used as the light projecting member 23. Further, the light projecting member 23 is provided with a filter member 25 that transmits the fluorescence converted in wavelength by the fluorescent member 22 and blocks excitation light of 405 nm, and the distance W between the filter member 25 and the target 30 is 5 m.

The color unevenness was evaluated from the relationship between the occupation ratio of the phosphor particles 29 contained in the light emission spot 22b and the standard deviation of the correlated color temperature distribution. In this evaluation, a plurality of fluorescent members 22 having different occupying ratios of the phosphor particles 29 contained in the light emitting spot 22b are prepared, and excitation light is applied to each fluorescent member 22 so that the light emitting area of the effective light emitting region 22c is 0.029 mm ^2. Was irradiated.

  FIG. 7 shows the relationship between the occupation ratio of the phosphor particles 29 contained in the light emission spot 22b and the median diameter. The vertical axis represents the occupation ratio (%) of the phosphor particles 29 contained in the light emission spot 22, and the horizontal axis represents the median diameter (μm) of the phosphor particles 29 contained in the light emission spot 22b. As shown in FIG. 7, as the median diameter of the phosphor particles 29 increases, the occupation ratio of the phosphor particles 29 included in the light emission spot 22b increases.

  The correlated color temperature distribution was determined by measuring the angular distribution of the correlated color temperature of the light projected on the target 30 in the dark room. The measurement angle was measured in 0.5 ° steps in the range of 87.5 ° to 92.5 °. The correlated color temperature varies randomly according to the measurement angle. For this reason, the measurement was performed four times by changing the direction of scanning in only one direction. The standard deviation of the correlated color temperature was derived from the average value of the correlated color temperatures measured four times.

  FIG. 8 shows the relationship between the standard deviation of the color temperature distribution and the occupation ratio of the phosphor particles 29 included in the light emission spot 22b. The vertical axis represents the standard deviation (K) of the color temperature distribution, and the horizontal axis represents the occupation ratio (%) of the phosphor particles 29 per particle contained in the light emission spot 22b. As shown in FIG. 8, when the occupation ratio of the phosphor particles 29 included in the light emission spot 22b exceeds 0.53%, the standard deviation of the color temperature distribution increases rapidly. For this reason, it was confirmed that the color unevenness is eliminated by setting the occupation ratio of the phosphor particles 29 included in the light emission spot 22b to 0.5% or less.

  According to the present embodiment, the phosphor particles 29 that are converted into fluorescence of different colors are excited by the excitation light emitted from the light collecting member 21, and the fluorescent light having a predetermined wavelength is emitted from the light emission spot 22b. The fluorescence emitted from the light emitting spot 22b is reflected by the light projecting member 23 and projected in a predetermined direction (A direction). At this time, based on the median diameter of the phosphor particles 29 in the light emission spot 22b with respect to the light emission area L of the effective light emission spot 22c having a light intensity of 50% or more with respect to the maximum light intensity of the fluorescence emitted from the light emission spot 22b. By setting the area of the circle derived in this way to 0.5% or less, the ratio of the phosphor particles 29 to one light emitting spot 22b that emits fluorescence becomes relatively small. Thereby, generation | occurrence | production of the color nonuniformity of the fluorescence light-emitted from the light emission spot 22b can be suppressed. Therefore, even when the phosphor particle 29 is excited with a high light density by reducing the irradiation area of the excitation light that irradiates the fluorescent member 22, and the light emitting spot 22b is used as a light source with high luminance, the light projecting member 23 projects the light. The occurrence of color unevenness can be suppressed in the projected area.

  In addition, since the fluorescent member 22 has the region irradiated with the excitation light and the light emission spot 22b formed on the same surface, the excitation light and the fluorescence scattered inside the fluorescent member 22 are small. For this reason, the light emission spot can be brought close to the area of the irradiation region. Therefore, it is possible to reduce the irradiation area of the excitation light irradiated to the fluorescent member 22 and emit the fluorescence from the light emitting spot 22b with a high light density.

  Further, by using a semiconductor laser element that emits laser light as the semiconductor light emitting element 20, the fluorescent member 22 can be irradiated with excitation light having a high light density in a smaller irradiation region. For this reason, it is possible to easily obtain a light source having high luminance in the light emission spot 22b of the fluorescent member 22.

Second Embodiment
FIG. 9 is a side sectional view of the light projecting device according to the second embodiment, and FIG. 10 is a diagram for explaining the emission area of the fluorescence emitted from the fluorescent member according to the second embodiment. The upper part of FIG. 10 is a side view of the fluorescent member 22, the middle part is a top view of the fluorescent member 22, and the lower part shows the light intensity distribution on the line of the light emission spot 22b. In addition, the same part as 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description. In contrast to the first embodiment, in the second embodiment, the laser beams emitted from the plurality of semiconductor light emitting elements 20 are condensed by the respective condensing members 21 and emitted to the fluorescent member 22, and light emission spots corresponding to the respective excitation lights. 22b overlap each other. In FIG. 10, two light emission spots 22b are overlapped, but three or more light emission spots 22b may be overlapped. Moreover, although the condensing lens is used for the condensing member 21, you may use an optical fiber. In addition, one window portion 23b is provided for the three semiconductor elements 20, but may be provided separately.

  At this time, even in the overlapping light emission spots 22b, the maximum fluorescence light emitted from each light emission spot 22b is the area of a circle derived based on the median diameter of the phosphor particles 29 in each light emission spot 22b excited by each excitation light. The light emission area having a light intensity of 50% or more with respect to the intensity is 0.5% or less. Accordingly, the phosphor particles 29 can be excited at a high light density in the overlapping light emission spots 22b, and color unevenness of the fluorescence emitted from each light emission spot 22b is suppressed. Therefore, a brighter light source using a single excitation source can be obtained.

<Third Embodiment>
FIG. 11 is a side sectional view of the light projecting device according to the third embodiment. In addition, the same part as 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description. In contrast to the first embodiment, in the third embodiment, the irradiation surface 22a on which the excitation light of the fluorescent member 22 is irradiated and the surface including the light emission spot 22b from which the fluorescence is emitted are arranged to face each other. That is, in the fluorescent member 22 of the third embodiment, light is extracted from the emission surface opposite to the irradiation surface 22a irradiated with the excitation light.

  At this time, the area of a circle derived on the basis of the median diameter of the phosphor particles in the light emission spot with respect to the light emission area having a light intensity of 50% or more with respect to the maximum light intensity of the fluorescence emitted from the light emission spot 22b. By setting it to 0.5% or less, it is possible to suppress the occurrence of uneven color of emitted fluorescence. However, in the light projecting device 1 of the present embodiment, excitation light and fluorescence are scattered inside the fluorescent member 22, and the light emission spot 22b becomes larger than the irradiation region of the excitation light. For this reason, the irradiation area | region of excitation light and the light emission spot 22b do not correspond. Therefore, in order to realize a high-intensity light source by reducing the light emitting spot 22b, the reflection type light projecting device 1 having the light emitting spot 22b on the surface irradiated with the excitation light as in the light projecting device 1 of the first embodiment. Is more preferable.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  Moreover, in the said embodiment, although the example which used the light projector of this invention for the headlamp of a motor vehicle was shown, this invention is not restricted to this. You may use the light projection apparatus of this invention for the headlamp of an airplane, a ship, a robot, a motorcycle or a bicycle, and another moving body.

  Moreover, although the example which converted excitation light into visible light was shown in the said embodiment, this invention is not limited to this, You may convert excitation light into light other than visible light. For example, when the excitation light is converted into infrared light, it can also be applied to a night illumination device of a security CCD camera.

DESCRIPTION OF SYMBOLS 1 Light projection apparatus 20 Semiconductor light-emitting element 21 Condensing member 22 Fluorescence member 22a Irradiation surface 22b Light emission spot 23 Light projection member 23a Reflection surface 24 Mounting member 24a Upper surface 24b Mounting part 25 Filter member 29 Phosphor particle F23 Focus V23 Vertex

Claims (4)

A semiconductor light emitting device that emits light, a light collecting member that collects light from the semiconductor light emitting device and emits spot-like excitation light, and a plurality of types of fluorescence that converts the excitation light into fluorescent light of different colors In a light projecting device comprising a fluorescent member that includes body particles and emits fluorescence from a spot-like light emission spot corresponding to the excitation light, and a light projecting member that projects fluorescence emitted from the fluorescent member to a predetermined region,
The median diameter of the phosphor particles in the light emission spot is 10 μm or more, and the area of a circle derived based on the median diameter of the phosphor particles in the light emission spot is the maximum fluorescence light emitted from the light emission spot projecting light Ri Do to 0.5% or less of the light-emitting area of the effective light emitting area having 50% or more of the light intensity relative to intensity, the light-emitting area of the effective light-emitting region, characterized in that it is 0.1 mm ² or less apparatus.   The light projecting device according to claim 1, wherein a plurality of spot-like excitation lights are emitted from the light collecting member, and the light emission spots corresponding to the respective excitation lights overlap each other.   The light projecting device according to claim 1, wherein the light emitting spot is formed on a surface of the fluorescent member on which the excitation light is irradiated.   The light projecting apparatus according to claim 1, wherein the semiconductor light emitting element is a semiconductor laser element that emits laser light.

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