JP2019159110A - Light source device and light projection device - Google Patents

Abstract

To provide a light source device capable of detecting a light scan position with high accuracy and a light projection device using the same.SOLUTION: A light source device 2 comprises laser light sources 11a-11c, a wavelength conversion member 18 converting wavelength of a laser beam emitted from the laser light sources 11a-11c into different wavelength and diffusing the light converted in wavelength, an optical deflector 16 making the laser beam emitted from the laser light sources 11a-11c scan on an incidence plane of the wavelength conversion member 18 and a photodetector 21 placed outside a scan range on the incidence plane in a scan direction of the laser beam on the incidence plane and receiving light diffused by the wavelength conversion member 18 to output a detection signal according to the amount of received light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light source device that emits light and a light projecting device using the light source device.

  Conventionally, there has been known a light source device that generates light having a predetermined wavelength by irradiating a wavelength conversion member with light emitted from a laser light source. In this light source device, for example, light that has been subjected to wavelength conversion by the wavelength conversion member and diffused and light that has been diffused without being subjected to wavelength conversion by the wavelength conversion member are combined to generate light of a predetermined color such as white light. Generated. Such a light source device is used, for example, as a light source device for a vehicle headlamp.

  The following Patent Document 1 describes a vehicle headlamp that uses an optical sensor to detect a light scanning position. The vehicle headlamp includes a laser light source, a micromirror, and an optical sensor. The micromirror is swingable around one axis, and deflects the laser beam of the laser light source toward the light emitting surface having the light conversion phosphor. The light image generated on the light emitting surface is projected onto the road via the optical system. The optical sensor is disposed with respect to the light emitting surface so as to detect a secondary laser beam emitted from the light emitting surface at a predetermined swing position of the micromirror.

Japanese translation of PCT National Publication No. 2006-528671

  In the configuration of Patent Document 1, the state of the optical deflector cannot be detected when the micromirror is in a position other than the predetermined swing position. For this reason, the detection accuracy of the light scanning position is lowered.

  In view of such a problem, an object of the present invention is to provide a light source device capable of accurately detecting a light scanning position and a light projecting device using the light source device.

  A first aspect of the present invention relates to a light source device. The light source device according to this aspect includes a laser light source, a wavelength conversion member that converts the wavelength of the laser light emitted from the laser light source into another wavelength and diffuses the wavelength-converted light, and the light emitted from the laser light source. An optical deflector that scans the laser beam on the incident surface of the wavelength conversion member, and the laser beam is disposed outside the scanning range on the incident surface in the scanning direction of the laser light on the incident surface. A photodetector that receives light diffused by the member and outputs a detection signal corresponding to the amount of light received.

  According to the light source device according to this aspect, since the photodetector is arranged outside the scanning range in the scanning direction, when the laser beam scans the incident surface of the wavelength conversion member, the scanning position approaches the photodetector. As a result, the amount of light received by the photodetector gradually increases. Therefore, the scanning position of the laser beam on the incident surface of the wavelength conversion member can be detected for the entire scanning range by the detection signal of the photodetector. Therefore, the light scanning position can be detected with high accuracy.

  A 2nd aspect of this invention is related with a light projector. The light projecting device according to this aspect includes the light source device according to the first aspect and a projection optical system that projects the light diffused by the wavelength conversion member.

  According to the light projecting device according to the present aspect, the same effects as those of the first aspect are achieved. In addition, since the light scanning position can be detected with high accuracy in the light source device, light can be accurately projected onto the target area.

  As described above, according to the light source device and the light projecting device of the present invention, the light scanning position can be detected with high accuracy.

  The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the embodiment described below is merely an example when the present invention is implemented, and the present invention is not limited to what is described in the following embodiment.

FIGS. 1A and 1B are a side view and a plan view, respectively, showing the configuration of the light projecting device according to the embodiment. FIG. 2A is a side view schematically showing the configuration of the wavelength conversion member according to the embodiment. FIG. 2B is a plan view schematically showing the configuration of the wavelength conversion member according to the embodiment. FIG. 3A is a schematic diagram when the wavelength conversion member, the optical filter, the condenser lens, and the photodetector according to the embodiment are viewed in the negative Y-axis direction. FIG. 3B is a graph schematically showing the relationship between the scanning position according to the embodiment and the amount of received light in the yellow wavelength band received by the photodetector. FIG. 4A is a schematic diagram when the wavelength conversion member, the optical filter, the condenser lens, and the photodetector according to Comparative Example 1 are viewed in the negative Y-axis direction. FIG. 4B is a graph schematically showing the relationship between the scanning position according to Comparative Example 1 and the amount of light received in the yellow wavelength band received by the photodetector. FIG. 5A is a schematic diagram when the wavelength conversion member, the optical filter, the condensing lens, and the photodetector according to Comparative Example 2 are viewed in the negative Z-axis direction. FIG. 5B is a graph schematically showing the relationship between the scanning position according to Comparative Example 2 and the amount of light received in the yellow wavelength band received by the photodetector. FIG. 6 is a circuit block diagram illustrating a main circuit configuration of the light source device according to the embodiment. FIG. 7A is a diagram schematically illustrating the movement of the beam spot on the incident surface of the wavelength conversion member when the swing angle of the mirror according to the embodiment is lower than a predetermined swing angle. FIG. 7B is a graph schematically showing the relationship between the scanning position according to the embodiment and the amount of light received in the yellow wavelength band received by the photodetector. FIG. 8A is a diagram schematically illustrating the movement of the beam spot on the incident surface of the wavelength conversion member when the scanning range according to the embodiment is shifted in the negative X-axis direction. FIG. 8B is a graph schematically showing the relationship between the scanning position according to the embodiment and the amount of light received in the yellow wavelength band received by the photodetector. FIG. 9 is a graph schematically showing the relationship between the elapsed time according to the embodiment and the amount of light received in the yellow wavelength band received by the photodetector. Drawing 10 (a)-(c) is a mimetic diagram showing that the state of the wavelength conversion member concerning an embodiment changes. FIG. 10D is a graph schematically illustrating the relationship between the scanning position and the amount of received light when the wavelength conversion member according to the embodiment is in an appropriate state. 10E and 10F are graphs schematically showing the relationship between the scanning position and the amount of received light when the state of the wavelength conversion member according to the embodiment changes. FIG. 11 is a flowchart illustrating a process for detecting an abnormality of the wavelength conversion member according to the embodiment. FIGS. 12A and 12B are a side view and a plan view, respectively, showing the configuration of the light projecting device according to the first modification. FIG. 13A is a schematic diagram when the wavelength conversion member, the optical filter, the condensing lens, and the photodetector according to Modification 2 are viewed in the positive direction of the Z axis. FIG. 13B is a graph schematically illustrating the relationship between the horizontal scanning position and the amount of received light in each scanning line according to the second modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, the X, Y, and Z axes orthogonal to each other are appended to each drawing. The positive Z-axis direction is the direction in which the light projecting device 1 projects light.

  FIGS. 1A and 1B are a side view and a plan view showing the configuration of the light projecting device 1, respectively.

  The light projecting device 1 includes a light source device 2 that generates light, and a projection optical system 3 that projects light generated by the light source device 2. The projection optical system 3 includes two lenses 3a and 3b. The light from the light source device 2 is condensed by these lenses 3a and 3b and projected onto the target area. In addition, the projection optical system 3 does not necessarily need to be comprised from the two lenses 3a and 3b, for example, may be one lens and may be provided with two or more lenses and mirrors. Further, the projection optical system 3 may be configured to condense light from the light source device 2 using a concave mirror.

  The light source device 2 includes three laser light sources 11a to 11c, three collimator lenses 12a to 12c, two reflecting prisms 13a and 13b, a cylindrical lens 14, a reflecting mirror 15, an optical deflector 16, and a cylindrical mirror. 17, a wavelength conversion member 18, an optical filter 19, a condenser lens 20, and a photodetector 21. The above-mentioned members constituting the light source device 2 are installed on a base (not shown) together with the projection optical system 3.

  Each of the laser light sources 11a to 11c emits a laser beam in a blue wavelength band (for example, 450 nm). The laser light sources 11a to 11c are made of, for example, a semiconductor laser. The laser light sources 11a to 11c are laser light sources of the same model. The wavelength of the laser light emitted from the laser light sources 11a to 11c can be changed as appropriate. The laser light sources 11a to 11c are not necessarily a single-emitter semiconductor laser having a single light-emitting region, and may be, for example, a multi-emitter semiconductor laser having a plurality of light-emitting regions in one light-emitting element. The laser light sources 11a to 11c do not necessarily emit laser light in a single wavelength band, and may be, for example, a multi-emitting semiconductor laser in which a plurality of light emitting elements are mounted on one substrate.

  The collimator lenses 12a to 12c convert the laser beams emitted from the laser light sources 11a to 11c into parallel beams, respectively. The reflecting prisms 13a and 13b reflect the laser light transmitted through the collimator lenses 12b and 12c in the direction toward the cylindrical lens 14, respectively. Instead of the reflecting prisms 13a and 13b, a plate-like reflecting mirror may be used.

  As shown in FIG. 1B, the laser light sources 11b and 11c are arranged so as to face each other. The reflecting prisms 13a and 13b are arranged so that a gap is formed in the direction in which the laser light sources 11b and 11c face each other, that is, in the X-axis direction. The laser light sources 11a to 11c are arranged so that the emission optical axis is included in one plane parallel to the XZ plane.

  The laser light emitted from the laser light source 11a is converted into parallel light by the collimator lens 12a, and then travels toward the cylindrical lens 14 through the gap between the reflecting prisms 13a and 13b. The optical axes of the laser light sources 11b and 11c arranged opposite to each other are bent in a direction parallel to the XZ plane by the reflecting prisms 13a and 13b. Thereby, the laser beams emitted from the laser light sources 11a to 11c are incident on the incident surface of the cylindrical lens 14 at different positions in the X-axis direction.

  With the above configuration, the three laser beams can be brought close to each other without being limited to the package of the laser light sources 11a to 11c and the outer shape of the cap. As a result, the total width of the bundle of three laser beams incident on the cylindrical lens 14 can be reduced. As a result, the optical system after the cylindrical lens 14 can be made compact, and the influence of the aberration of the optical system can be reduced. Further, the size of the mirror 16a of the optical deflector 16 can be reduced, and an increase in the size of the optical deflector 16 and an increase in power consumption can be suppressed.

  The laser light emitted from the laser light source 11 a is incident on the center position of the incident surface of the cylindrical lens 14. The laser beams emitted from the laser light sources 11b and 11c are incident on positions shifted by a predetermined distance from the center position of the incident surface of the cylindrical lens 14 in the X axis positive / negative direction.

  The cylindrical lens 14 has a curved surface whose entrance surface is curved only in a direction parallel to the XZ plane. The incident surface of the cylindrical lens 14 is aspheric, and the exit surface of the cylindrical lens 14 is a plane perpendicular to the Z axis. The exit surface of the cylindrical lens 14 may also be a curved surface curved in a direction parallel to the XZ plane. Alternatively, the incident surface of the cylindrical lens 14 may be a flat surface and the output surface may be a curved surface.

  The cylindrical lens 14 is disposed so that the generatrix of the incident surface is perpendicular to the plane including the optical axes of the three laser beams incident on the incident surface, that is, parallel to the Y-axis direction. The cylindrical lens 14 has convergent power only in the direction in which the three optical axes of the laser light sources 11a to 11c are aligned at the incident position, that is, in the X-axis direction. Laser light emitted from the laser light sources 11 a to 11 c is converged in the scanning direction of the laser light on the incident surface of the wavelength conversion member 18 by the cylindrical lens 14. As will be described later, the beam spots of the three laser beams are substantially integrated into one beam spot by being close to each other on the incident surface of the wavelength conversion member 18.

  The beam spots of the three laser beams may be completely overlapped on the incident surface of the wavelength conversion member 18 or may be slightly shifted in the scanning direction. If the optical axes of the three laser beams incident on the cylindrical lens 14 are all parallel to the Z axis, the beam spots of the three laser beams overlap substantially completely on the incident surface of the wavelength conversion member 18. If the optical axis of the X-axis negative laser beam and the optical axis of the X-axis positive laser beam are inclined in the X-axis positive / negative direction with respect to the Z-axis at the incident position of the cylindrical lens 14, respectively, three lasers The beam spot of light is shifted in the scanning direction on the incident surface of the wavelength conversion member 18. Therefore, by adjusting the layout of the optical system before the cylindrical lens 14, it is possible to adjust the overlapping state of the three laser beam spots on the incident surface of the wavelength conversion member 18.

  The reflection mirror 15 bends the optical axes of the three laser beams transmitted through the cylindrical lens 14 in directions parallel to the YZ plane. The three laser beams are reflected by the reflection mirror 15 and then enter the mirror 16 a of the optical deflector 16. The reflection mirror 15 may be omitted depending on the layout of the optical system from the cylindrical lens 14 to the wavelength conversion member 18. In this case, the three laser beams transmitted through the cylindrical lens 14 are directly incident on the mirror 16 a of the optical deflector 16.

  The optical deflector 16 includes a mirror 16a, and changes the traveling direction of the laser light reflected by the reflection mirror 15 by rotating the mirror 16a about a rotation axis L1 parallel to the Z axis. The incident surface of the mirror 16a is a plane. The mirror 16a is, for example, a high reflectance mirror in which a dielectric multilayer film is formed on a glass plate. The mirror 16a is arranged to be parallel to the XZ plane in the neutral position. The optical deflector 16 is composed of, for example, a MEMS (Micro Electro Mechanical Systems) mirror.

  The cylindrical mirror 17 is a reflecting surface whose incident surface is curved concavely only in a direction parallel to the YZ plane. The incident surface of the cylindrical mirror 17 is a spherical surface, but may be an aspherical surface. The cylindrical mirror 17 is arranged so that the generatrix of the incident surface is parallel to a plane including the optical axes of the three laser beams incident on the incident surface, that is, parallel to the X-axis direction. The cylindrical mirror 17 has a convergence power only in the direction perpendicular to the direction in which the three optical axes of the laser light sources 11a to 11c are aligned at the incident position, that is, in the direction parallel to the YZ plane. The laser light emitted from the laser light sources 11 a to 11 c is converged in a direction perpendicular to the scanning direction of the laser light on the incident surface of the wavelength conversion member 18 by the cylindrical mirror 17.

  Note that, depending on the layout of the optical system from the optical deflector 16 to the wavelength conversion member 18, the cylindrical mirror 17 can be replaced with a transmission type cylindrical lens. In this case, the three laser beams incident on the cylindrical lens are incident on the wavelength conversion member 18 after being subjected to a converging action in a direction parallel to the YZ plane by the cylindrical lens.

  Further, the incident surface of the mirror 16a may be replaced with a cylindrical mirror surface. In this case, the cylindrical mirror 17 is omitted or is a flat reflecting mirror, and the three laser beams incident on the cylindrical lens 14 are converged in a direction parallel to the YZ plane by the cylindrical mirror 16a. After receiving, the light passes through the reflection mirror or directly enters the wavelength conversion member 18 as it is.

  The wavelength conversion member 18 is disposed at a position where the laser beam reflected by the cylindrical mirror 17 is incident. The wavelength conversion member 18 is a rectangular plate-shaped member, and is installed so that the incident surface is parallel to the XY plane. As described above, when the mirror 16a rotates about the rotation axis L1, the wavelength conversion member 18 is scanned in the longitudinal direction (X-axis direction) by the laser beam.

  The wavelength conversion member 18 converts part of the incident laser light into a wavelength different from the blue wavelength band and diffuses it in the Z-axis direction. Other laser light that has not undergone wavelength conversion is diffused in the Z-axis direction by the wavelength conversion member 18. The light of the two types of wavelengths diffused in this way is combined to generate light of a predetermined color. Light of each wavelength is taken into the projection optical system 3 and projected onto the target area.

  In the present embodiment, the wavelength conversion member 18 converts part of the laser light into light in the yellow wavelength band. The diffused light in the yellow wavelength band after wavelength conversion and the scattered light in the blue wavelength band that has not been wavelength-converted are combined to generate white light. In addition, the wavelength after wavelength conversion may not be a yellow wavelength range, and the color of the light produced | generated may be colors other than white.

  In addition, the spread angle of the light in the yellow wavelength band and the light in the blue wavelength band diffused by the wavelength conversion member 18 is an angle close to 180 ° on the entire circumference around the Z axis. Of the light in the yellow wavelength band and the light in the blue wavelength band that diffuses in this way, light of each wavelength in a predetermined angle range from the center is taken into the lenses 3a and 3b and projected onto the target area. Further, part of the diffused light outside the angle range enters the condenser lens 20 through the optical filter 19 disposed on the side of the wavelength conversion member 18 and is collected by the photodetector 21. The In the present embodiment, the optical filter 19, the condenser lens 20, and the photodetector 21 are installed on the X axis negative side of the wavelength conversion member 18. Therefore, of the diffused light outside the angle range, a part of the diffused light on the X axis negative side is directed to the photodetector 21.

  The optical filter 19 is configured to transmit yellow wavelength band light among the light diffused by the wavelength conversion member 18. Further, the transmittance of the optical filter 19 is set so that the amount of light incident on the subsequent photodetector 21 becomes an appropriate level. The condensing lens 20 condenses the light in the yellow wavelength band transmitted through the optical filter 19 on the light receiving surface of the photodetector 21. The photodetector 21 is, for example, a photodiode. The photodetector 21 receives light in the yellow wavelength band collected by the condenser lens 20 on the light receiving surface, and outputs a detection signal corresponding to the received light quantity in the yellow wavelength band. The arrangement of the photodetector 21 and the control based on the detection signal of the photodetector 21 will be described later.

  The optical filter 19 may be configured to transmit only the light in the blue wavelength band among the light diffused by the wavelength conversion member 18 or may be configured to transmit the synthesized white light. . However, when the light receiving element of the photodetector 21 is a silicon substrate, the light in the blue wavelength band is difficult to receive with high sensitivity because the light receiving sensitivity to blue light is lower than that of yellow light. Therefore, as in the embodiment, it is preferable that the optical filter 19 is configured to transmit light in the yellow wavelength band, and the photodetector 21 receives light in the yellow wavelength band.

  FIG. 2A is a side view schematically showing the configuration of the wavelength conversion member 18.

  The wavelength conversion member 18 has a configuration in which a reflective film 102 and a phosphor layer 103 are laminated on the upper surface of the substrate 101.

The substrate 101 is made of, for example, silicon, aluminum nitride ceramic, sapphire glass, or the like. The reflective film 102 is configured by laminating a first reflective film 102a and a second reflective film 102b. The first reflective film 102a is, for example, a metal film such as Ag, an Ag alloy, or Al. The second reflective film 102b also has a function of protecting the first reflective film 102a from oxidation and the like as well as reflection. For example, SiO ₂ , ZnO, ZrO ₂ , Nb ₂ O ₅ , Al ₂ O ₃ , TiO _2. , SiN, AlN, or other dielectric material. The reflective film 102 does not necessarily have to be composed of the first reflective film 102a and the second reflective film 102b, and may be a single layer or a structure in which three or more layers are laminated.

  The phosphor layer 103 is formed by fixing phosphor particles 103a with a binder 103b. The phosphor particles 103a emit fluorescence in the yellow wavelength band when irradiated with laser light in the blue wavelength band emitted from the laser light sources 11a to 11c. For example, (YnGd1-n) 3 (AlmGa1-m) 5O12: Ce (0.5 ≦ n ≦ 1, 0.5 ≦ m ≦ 1) having an average particle diameter of 1 μm to 30 μm is used as the phosphor particles 103a. . Further, as the binder 103b, a transparent material mainly containing silsesquioxane such as polymethylsilsesquioxane is used.

  Furthermore, it is preferable to provide a void 103 c inside the phosphor layer 103. As a result, the laser light that has entered the interior can be more efficiently scattered and taken out from the light source device 2. Further, since the void 103c exists in the vicinity of the second reflective film 102b, it is possible to effectively scatter laser light and fluorescence while reducing energy loss due to the surface of the second reflective film 102b. It is desirable that the phosphor layer 103 further includes a filler 103d for increasing strength and heat resistance.

  Laser light emitted from the laser light sources 11 a to 11 c is irradiated to the excitation region R 1 shown in FIG. 2A, and is scattered and absorbed on the surface or inside of the phosphor layer 103. At this time, a part of the laser light is converted into yellow wavelength band light by the phosphor particles 103 a and emitted from the phosphor layer 103. The other part of the laser light is scattered without being converted into light in the yellow wavelength band, and is emitted from the phosphor layer 103 as light in the blue wavelength band. At this time, since light in each wavelength band is scattered while propagating through the phosphor layer 103, the light is emitted from the light emitting region R2 that is slightly wider than the excitation region R1 and has a different region width depending on the wavelength band.

  FIG. 2B is a plan view schematically showing the configuration of the wavelength conversion member 18.

  The wavelength conversion member 18 has a rectangular shape that is long in the X-axis direction in plan view. The wavelength conversion member 18 is scanned in the X-axis direction with a laser beam when the mirror 16a of the optical deflector 16 is rotated. The mirror 16a is rotated in a predetermined angle range in both directions from a neutral position parallel to the XZ plane. In FIG. 2B, BS indicates one beam spot formed by integrating the laser beams emitted from the laser light sources 11a to 11c as described above. During normal scanning, the beam spot BS reciprocates on the incident surface 18a of the wavelength conversion member 18 within the width W1. That is, the scanning range of the beam spot BS during normal scanning is the range of the width W1.

  For example, a triangular wave drive signal (current) having an amplitude center of zero level is applied to a coil that drives the mirror 16a in the optical deflector 16. Due to the driving force excited in the coil by this driving signal, the mirror 16a rotates around a neutral position with a predetermined rotation width. Thereby, the laser beam (beam spot BS) reciprocates on the incident surface 18a of the wavelength conversion member 18 in the width W1.

  In FIG. 2B, the reciprocating movement of the beam spot BS is indicated by a straight arrow. However, since the laser beam is incident on the wavelength conversion member 18 from an oblique direction, the actual movement locus of the beam spot BS is shown. Is a slightly curved locus in which both ends in the X-axis positive and negative directions are displaced in the Y-axis negative direction with respect to the center position in the X-axis direction.

  The region of the beam spot BS on the incident surface 18a corresponds to the excitation region R1 in FIG. While the beam spot BS moves on the incident surface 18a of the wavelength conversion member 18, the diffused light in the blue wavelength band and the diffused light in the yellow wavelength band from the light emitting region R2 slightly wider than the region of the beam spot BS in the positive direction of the Z axis. Radiated.

  The light of the two wavelength bands emitted in this way is taken in by the projection optical system 3 shown in FIGS. 1A and 1B and projected onto the target area. Accordingly, white light obtained by combining light in the blue wavelength band and light in the yellow wavelength band is projected from the light projecting device 1 onto the target area.

  FIG. 3A is a schematic diagram when the wavelength conversion member 18, the optical filter 19, the condenser lens 20, and the photodetector 21 are viewed in the negative Y-axis direction.

  The photodetector 21 is arranged outside the scanning range on the incident surface 18a in the laser beam scanning direction (X-axis direction). The optical filter 19 and the condensing lens 20 are also arranged outside the scanning range. In other words, the condensing lens 20 is disposed between the scanning range and the photodetector 21, and the optical filter 19 is disposed between the scanning range and the condensing lens 20. The optical filter 19 may be disposed between the condenser lens 20 and the photodetector 21. The optical filter 19, the condensing lens 20, and the photodetector 21 are arranged on the side where the light diffused by the wavelength conversion member 18 is generated, that is, on the incident surface 18a side (Z-axis positive side).

  When the laser beam (beam spot BS) scans the incident surface 18a, the amount of light received by the photodetector 21 gradually increases as the scanning position approaches the photodetector 21. That is, in the scanning direction (X-axis direction), if the scanning position farthest from the photodetector 21 is the position P11 and the scanning position closest to the photodetector 21 is the position P12, the photodetector when the scanning position is the position P11. When the scanning position is at position P12, the amount of light received by the photodetector 21 is maximized.

  The photodetector 21 does not necessarily have to be arranged so that the light receiving surface is parallel to the YZ plane as shown in FIG. 3A, and the light receiving surface is parallel to the YZ plane. You may arrange | position so that it may incline from. In addition, the photodetector 21 may be arranged so that the light receiving surface is parallel to the XZ plane, or may be arranged so that the light receiving surface is parallel to the XY plane. That is, the light detector 21 may be arranged so that the amount of light received by the light detector 21 gradually increases as the scanning position of the laser light approaches the light detector 21. Further, instead of the condensing lens 20, the light transmitted through the optical filter 19 may be condensed on the light receiving surface of the photodetector 21 by a concave mirror, and the light transmitted through the condensing lens 20 may be collected by a mirror. The light may be folded and condensed on the light receiving surface of the photodetector 21.

  FIG. 3B is a graph schematically showing the relationship between the scanning position and the amount of light received in the yellow wavelength band received by the photodetector 21. The horizontal axis of the graph indicates the spot position, that is, the scanning position of the laser beam in the scanning direction. The vertical axis indicates the amount of light received by the photodetector 21.

  As shown in FIG. 3B, the amount of light received by the photodetector 21 is minimized when the scanning position is the position P11, and the amount of light received by the photodetector 21 is maximized when the scanning position is the position P12. Further, as the scanning position approaches the photodetector 21, the amount of diffused light captured by the condenser lens 20 increases, so that the amount of light received by the photodetector 21 gradually increases. Therefore, the scanning position on the incident surface 18 a of the wavelength conversion member 18 can be detected based on the detection signal of the photodetector 21.

  FIG. 4A is a schematic diagram when the wavelength conversion member 18, the optical filter 19, the condenser lens 20, and the photodetector 21 according to Comparative Example 1 are viewed in the negative Y-axis direction. FIG. 4B is a graph schematically illustrating the relationship between the scanning position and the amount of received light according to Comparative Example 1.

  As shown in FIG. 4A, in the first comparative example, the condensing lens 20 is arranged in the scanning range as compared with the configuration of the embodiment shown in FIG. For this reason, as shown in FIG. 4B, the amount of received light increases as the scanning position approaches the position P12, but when the position approaches the position P12 rather than the position P13, the light taken into the condenser lens 20 rapidly decreases. For this reason, the amount of light received by the photodetector 21 also decreases rapidly. In this case, the scanning position cannot be properly detected at a position closer to the position P12 than the position P13. Further, as shown in FIG. 4B, when the amount of received light is A1, two corresponding scanning positions are generated, so that the scanning position cannot be specified based on the amount of received light.

  FIG. 5A is a schematic diagram when the wavelength conversion member 18, the optical filter 19, the condenser lens 20, and the photodetector 21 according to Comparative Example 2 are viewed in the negative Y-axis direction. FIG. 5B is a graph schematically showing the relationship between the scanning position and the amount of received light according to Comparative Example 2.

  As shown in FIG. 5A, in the comparative example 2, the optical filter 19, the condensing lens 20, and the photodetector 21 are scanned in comparison with the configuration of the embodiment shown in FIG. It is arranged outside the negative Y-axis direction of the range. For this reason, as shown in FIG. 5B, the amount of received light increases as the scanning position approaches the position P14 corresponding to the front of the photodetector 21 from the position P11, but the amount of received light increases as the position approaches the position P12 from the position P14. Will decrease. In this case as well, as in the first comparative example, two scanning positions corresponding to one light reception amount are generated, and thus the scanning position cannot be specified based on the light reception amount.

  In the case of Comparative Example 2, the position where the light generated from the position P11 is collected on the light receiving surface of the photodetector 21 and the position where the light generated from the position P12 is collected on the light receiving surface of the photodetector 21. Are greatly separated in the X-axis direction. For this reason, compared with embodiment, the large sized photodetector 21 will be needed.

  Thus, in the configurations of Comparative Examples 1 and 2, the scanning position of the laser beam on the incident surface 18a cannot be detected properly. In contrast, in this embodiment, as shown in FIGS. 3A and 3B, the optical filter 19, the condenser lens 20, and the photodetector 21 are outside the scanning range in the scanning direction of the laser light. Therefore, the scanning position of the laser beam on the incident surface 18a can be properly detected.

  FIG. 6 is a circuit block diagram illustrating a main circuit configuration of the light source device 2.

  The light source device 2 includes a controller 201, laser drive circuits 202a to 202c, a mirror drive circuit 203, a signal processing circuit 204, and an interface 205 as a circuit unit.

  The controller 201 includes an arithmetic processing circuit such as a CPU and a memory, and controls each unit according to a predetermined control program. The laser drive circuits 202a to 202c drive the laser light sources 11a to 11c in accordance with control signals from the controller 201, respectively. The mirror driving circuit 203 drives the mirror 16 a of the optical deflector 16 in accordance with a control signal from the controller 201. The signal processing circuit 204 processes the detection signal output from the photodetector 21.

  Based on the detection signal output from the signal processing circuit 204, the controller 201 calculates a position detection signal using a position detection table corresponding to the graph shown in FIG. The position detection table is stored in advance in the memory in the controller 201.

  Here, the position detection table is a table in which the scanning position of the laser beam on the incident surface 18a of the wavelength conversion member 18 is associated with the output value of the photodetector 21 (signal value from the signal processing circuit 204). In the position detection table, the scanning range from the position P11 to the position P12 shown in FIG. 3B is divided at a predetermined interval to define each scanning position. A signal value (signal value from the signal processing circuit 204) output from the photodetector 21 when there is a laser beam at each scanning position is described in the position detection table in association with each scanning position.

  The controller 201 acquires the scanning position associated with the signal value of the detection signal output from the signal processing circuit 204 from the position detection table, and detects the scanning position of the laser light on the incident surface 18a. When the signal value of the detection signal output from the signal processing circuit 204 is between adjacent signal values on the position detection table, the controller 201 uses, for example, the signal value of the detection signal output from the signal processing circuit 204. The scanning position associated with the closer signal value is acquired as the scanning position of the laser beam on the incident surface 18a. Instead of this, the controller 201 may interpolate adjacent signal values to acquire the scanning position of the laser light on the incident surface 18a.

  In addition, since the outputs of the laser light sources 11a to 11c gradually decrease due to deterioration over time, the amount of light received by the photodetector 21 also decreases accordingly. For this reason, it is necessary to adjust the signal value prescribed | regulated by the position detection table according to aged deterioration of the laser light sources 11a-11c. For example, when the light source device 2 is activated, the controller 201 drives the laser light sources 11a to 11c with the mirror 16a positioned at the neutral position, and acquires the signal value of the detection signal output from the signal processing circuit 204 at that time. To do. Then, the controller 201 compares the acquired signal value with the signal value associated with the scanning position corresponding to the mirror neutral position in the position detection table, and on the position detection table according to the ratio of both signals. The signal values associated with all scanning positions are updated. Based on the position detection table updated in this way, the controller 201 detects the scanning position of the laser beam on the incident surface 18a by the above processing.

  The interface 205 is an input / output circuit for the controller 201 to transmit / receive signals to / from an external control circuit such as a vehicle-side control circuit.

  The controller 201 monitors the scanning state of the laser beam with respect to the incident surface 18a of the wavelength conversion member 18 based on the detection signal input from the signal processing circuit 204, and determines whether the scanning state of the laser beam is appropriate as needed. Then, when the scanning state of the laser light with respect to the incident surface 18a of the wavelength conversion member 18 deviates from the predetermined scanning state, the optical deflector 16 is controlled so that the scanning state becomes appropriate. Hereinafter, a control example of the optical deflector 16 will be described.

  FIG. 7A is a diagram schematically illustrating the movement of the beam spot BS on the incident surface 18a of the wavelength conversion member 18 when the swing angle of the mirror 16a is lower than a predetermined swing angle.

  For example, the rotation width of the mirror 16a corresponding to the drive signal may be reduced from a predetermined rotation width due to aging degradation of the optical deflector 16 or the like. In this case, as shown in FIG. 7A, the movement width of the beam spot BS on the incident surface 18a of the wavelength conversion member 18 is reduced by 2ΔW with respect to the predetermined width W1. That is, the most X-axis negative position of the scanning position is from P11 to P21, and the most X-axis positive position of the scanning position is from P12 to P22. Thus, when the movement width of the beam spot BS decreases, the amount of light received by the photodetector 21 also changes accordingly. Specifically, as shown in FIG. 7B, the minimum amount of received light increases from A11 to A21 and the maximum amount of received light decreases from A12 to A22 compared to before the movement width decreases. To do. The scanning position when the amount of received light is A21 corresponds to P21, and the scanning position when the amount of received light is A22 corresponds to P22.

  In this case, the controller 201 sets the amplitude of the drive signal, that is, the zero level as the center of the amplitude for the mirror drive circuit 203 so that the minimum received light amount is A11 and the maximum received light amount is A12. Control is performed to increase the amplitude of the triangular drive signal. By this control, the movement width of the beam spot BS on the incident surface 18a of the wavelength conversion member 18 is matched with the predetermined width W1.

  FIG. 8A is a diagram schematically illustrating the movement of the beam spot BS on the incident surface 18a of the wavelength conversion member 18 when the scanning range is shifted in the negative X-axis direction.

  As shown in FIG. 8A, the scanning range by the beam spot BS may be offset by ΔW in the negative X-axis direction due to deterioration of the optical deflector 16 over time. In this case, the most X-axis negative position of the scanning position is from P11 to P23, and the most X-axis positive position of the scanning position is from P12 to P22. As a result, as shown in FIG. 8B, the minimum amount of received light decreases from A11 to A23 and the maximum amount of received light decreases from A12 to A22 as compared to before the scan range changes. The scanning position when the amount of received light is A23 corresponds to P23. Also in this case, the controller 201 controls the mirror drive circuit 203 so that the minimum received light amount is A11 and the maximum received light amount is A12. By this control, the offset of the scanning range on the incident surface 18a of the wavelength conversion member 18 is corrected.

  Furthermore, the controller 201 acquires the operating frequency of the mirror 16a by acquiring the time ΔT corresponding to one cycle of scanning of the beam spot BS.

  FIG. 9 is a graph schematically showing the relationship between the elapsed time and the amount of light received in the yellow wavelength band received by the photodetector 21.

  When the mirror 16a is driven, as shown in FIG. 9, the amount of light received by the photodetector 21 changes between A11 and A12 over time. The period in which the amount of received light increases from A11 to A12 and the period in which the amount of received light decreases from A12 to A11 each correspond to the scanning time required for scanning in one direction, and two consecutive scanning times are one of the mirror 16a. Corresponds to period driving. The time during which the amount of received light decreases from A12 to A11 and then increases again to A12, or the time during which the amount of received light increases from A11 to A12 and then decreases again to A11 is the time ΔT corresponding to one cycle. It is.

  Based on the detection signal of the photodetector 21, the controller 201 acquires, as ΔT, the time until the received light amount returns from A11 to A11 again, or the time until the received light amount returns from A12 to A12 again, as ΔT. The operating frequency of the optical deflector 16 is acquired. Then, the controller 201 controls the mirror drive circuit 203 so that the acquired operating frequency becomes a desired operating frequency. Thereby, even if the operating frequency changes due to external factors such as disturbance and temperature change, the optical deflector 16 can be controlled so as to have an appropriate operating frequency.

  In the present embodiment, in addition to the control of the optical deflector 16 as described above, the controller 201 executes a process for determining the state of the wavelength conversion member 18 based on the detection signal of the photodetector 21.

  10A to 10C are schematic views showing that the state of the wavelength conversion member 18 changes. FIG. 10A is a diagram illustrating a state in which the phosphor layer 103 is appropriate, and FIG. 10B is a diagram illustrating a state in which a part of the thickness of the phosphor layer 103 is moderately reduced. FIG. 10C shows a state in which the thickness of a part of the phosphor layer 103 is greatly reduced.

  Due to factors such as the continued irradiation of high-power laser light, the thickness of part of the phosphor layer 103 in the wavelength conversion member 18 gradually decreases from the initial thickness, or part of the phosphor layer 103 due to external factors. Can be deficient. When the thickness of the phosphor layer 103 is reduced or lost in this way, the excited fluorescence is reduced, and light of a desired color is not output. Further, when the phosphor layer 103 disappears completely in a part of the region, almost all of the light irradiated to the region is reflected laterally by the reflection film 102 and is not taken into the projection optical system 3. In addition, depending on the optical configuration, the phosphor layer 103 disappears, so that laser light is emitted in the positive direction of the Z axis, and high-power dangerous light may be emitted to the outside.

  That is, in the state of FIG. 10A, the diffused light 32 including the blue wavelength band light 32 a and the yellow wavelength band light 32 b is appropriately generated based on the laser light 31 irradiated on the wavelength conversion member 18. In the state of FIG. 10B, since a part of the phosphor layer 103 is reduced, the yellow wavelength band light 32 b diffusing based on the laser light 31 is reduced. At this time, the laser light 31 is less likely to be converted into light in the yellow wavelength band than in the state of FIG. 10A, so the light 32 a in the blue wavelength band that diffuses based on the laser light 31 slightly increases. . In the state of FIG. 10C, since a part of the phosphor layer 103 has substantially disappeared, most of the laser light 31 is reflected by the reflective film 102, and as a result, the blue color diffuses based on the laser light 31. The wavelength band light 32a and the yellow wavelength band light 32b are significantly reduced. In this case, particularly the light 32b in the yellow wavelength band is greatly reduced.

  As described above, when the thickness of the phosphor layer 103 decreases or the phosphor layer 103 disappears in a part of the region, the color of the light generated in the part changes from a desired color, or The light irradiated to the part is not taken into the projection optical system 3.

  FIGS. 10D to 10F are graphs schematically showing the relationship between the scanning position and the amount of received light of the yellow wavelength band light 32 b received by the photodetector 21. The graphs of FIGS. 10D to 10F correspond to the wavelength conversion member 18 in the state illustrated in FIGS. 10A to 10C, respectively.

  10B and 10C, the phosphor layer 103 is reduced or missing in the vicinity of the scanning position P31. As described above, the light 32b in the yellow wavelength band decreases as the phosphor layer 103 decreases. For this reason, when the amount of decrease in the phosphor layer 103 is small as shown in FIG. 10B, as shown in FIG. 10E, a slightly falling portion occurs in the curve indicating the amount of received light. As shown in FIG. 10C, when the amount of decrease in the phosphor layer 103 is large, a portion of the curve indicating the amount of received light falls greatly. Therefore, it is possible to determine the state of the wavelength conversion member 18 (phosphor layer 103) by determining how much falling occurs in the curve based on the detection signal of the photodetector 21.

  When the optical filter 19 is configured to selectively transmit the light 32a in the blue wavelength band, the photodetector 21 outputs a detection signal based on the light 32a in the blue wavelength band. In this case, if the amount of decrease in the phosphor layer 103 is small as shown in FIG. 10 (b), a slightly rising portion occurs in the curve indicating the amount of received light, and the phosphor layer as shown in FIG. 10 (c). When the amount of decrease 103 is large, a falling portion occurs in the curve indicating the amount of received light. Therefore, the state of the wavelength conversion member 18 (phosphor layer 103) can be determined by determining how much rising or falling occurs in the curve based on the detection signal of the photodetector 21.

  When the optical filter 19 is not disposed, or when the optical filter 19 is configured to selectively transmit both the light 32a in the blue wavelength band and the light 32b in the yellow wavelength band, the photodetector 21 is A detection signal based on light in one wavelength band (the entire diffused light) is output. In this case, if the amount of decrease in the phosphor layer 103 is small as shown in FIG. 10B, a slightly falling portion occurs in the curve indicating the amount of received light, and the phosphor as shown in FIG. 10C. When the amount of decrease in the layer 103 is large, a portion that falls significantly in the curve indicating the amount of received light occurs. Therefore, it is possible to determine the state of the wavelength conversion member 18 (phosphor layer 103) by determining how much falling occurs in the curve based on the detection signal of the photodetector 21.

  In the curve of the amount of received light based on the light 32b in the yellow wavelength band, the determination of how much the fall has occurred is made based on the fall amount ΔA. Specifically, as shown in FIGS. 10E and 10F, in the curve of the received light amount (detection signal of the photodetector 21), the value of the received light amount at the left boundary of the falling portion and the falling portion The difference from the minimum value of the amount of received light is acquired as the fall amount ΔA, and the state of the wavelength conversion member 18 is determined by comparing the fall amount ΔA with a predetermined threshold Ath.

  FIG. 11 is a flowchart showing a process for detecting an abnormality of the wavelength conversion member 18.

  Based on the detection signal output from the signal processing circuit 204, the controller 201 acquires a detection signal curve corresponding to scanning in one direction of the scanning range (S11). For example, the controller 201 acquires curve data of the detection signal by acquiring the value of the detection signal at a predetermined time interval (sampling period) in scanning in one direction of the scanning range. The controller 201 acquires the fall amount ΔA described above from the curve of the detection signal acquired in step S11 (S12). Subsequently, the controller 201 reads the threshold value Ath stored in the internal memory of the controller 201 in advance, and determines whether the falling amount ΔA acquired in step S12 exceeds the threshold value Ath (S13). Here, the threshold value Ath is set to a value that is higher than a noise component that can be superimposed on the curve and that can appropriately detect that an abnormality (decrease or disappearance) has occurred in the wavelength conversion member 18.

  When the falling amount ΔA exceeds the threshold value Ath (S13: YES), the controller 201 ends the lighting of the laser light sources 11a to 11c and sets a flag indicating that an abnormality has occurred in the wavelength conversion member 18 ( S14). In this case, the controller 201 may output a notification signal indicating that an abnormality has occurred in the wavelength conversion member 18 to an external control circuit (for example, a vehicle-side control circuit) via the interface 205.

  If there are a plurality of falling edges in the detection signal curve, in step S12, the controller 201 acquires a plurality of falling amounts ΔA corresponding to the plurality of falling edges, respectively. In step S13, the controller 201 determines whether each fall amount ΔA exceeds the threshold value Ath. If one or more fall amounts ΔA exceed the threshold value Ath, the process proceeds to step S14.

  On the other hand, when the falling amount ΔA does not exceed the threshold value Ath (S13: NO), the controller 201 skips step S14. The controller 201 repeatedly executes the processes of steps S11 to S14 until the power to the light source device 2 is shut off (S15: YES). When the power to the light source device 2 is shut off (S15: YES), the controller 201 ends the abnormality detection process of the wavelength conversion member 18.

  Note that the method for determining the state of the wavelength conversion member 18 (phosphor layer 103) based on the detection signal of the photodetector 21 is not limited to the method described with reference to FIGS. Absent. In the above method, the fall amount ΔA is acquired as a parameter value corresponding to the deterioration of the wavelength conversion member 18. For example, the number of falling branch points or the number of rising branch points in the scanning range in one direction is used as the parameter value. Alternatively, the number of peaks in a scanning range in one direction may be acquired as a parameter value. In this case, when one or more of these parameter values are present, it is detected that an abnormality has occurred in the wavelength conversion member 18. In addition, the difference between the received light amount at the position of the falling peak and the expected value of the received light amount at this position may be acquired as the parameter value. Also in this case, as in the above method, when the parameter value exceeds a predetermined threshold, it is detected that an abnormality has occurred in the wavelength conversion member 18. The parameter value may be a value that can detect the abnormality of the wavelength conversion member 18 based on the detection signal of the photodetector 21.

<Effect of embodiment>
As mentioned above, according to this embodiment, the following effects are produced.

  The photodetector 21 is disposed outside the scanning range in the scanning direction of the laser light on the incident surface 18a. For this reason, when the laser beam scans the incident surface 18 a of the wavelength conversion member 18, the amount of light received by the photodetector 21 gradually increases as the scanning position approaches the photodetector 21. Therefore, the scanning position of the laser beam on the incident surface 18a of the wavelength conversion member 18 can be detected for the entire scanning range by the detection signal of the photodetector 21. Therefore, the light scanning position can be detected with high accuracy.

  As described with reference to Comparative Example 2 in FIGS. 5A and 5B, when the photodetector 21 is disposed inside the scanning range in the scanning direction of the laser light, the scanning position of the laser light. Cannot be identified. On the other hand, when the photodetector 21 is arranged outside the scanning range in the scanning direction of the laser light as in this embodiment, the scanning position of the laser light can be detected for the entire scanning range. Further, the size of the photodetector 21 can be reduced as compared with the comparative example 2.

  A condensing lens 20 is disposed between the scanning range and the light detector 21, and a part of the light diffused by the wavelength conversion member 18 is condensed on the light receiving surface of the light detector 21 by the condensing lens 20. . Thereby, the amount of light received by the photodetector 21 is increased, so that the resolution when detecting the scanning position can be increased. Therefore, the scanning position can be detected with higher accuracy. Moreover, since the light-receiving surface of the photodetector 21 can be reduced, the light source device 2 can be reduced in size. Furthermore, since the light condensed by the condensing lens 20 can be turned back by a mirror, the degree of freedom in optical arrangement can be increased.

  As described with reference to Comparative Example 1 in FIGS. 4A and 4B, when the condenser lens 20 is disposed within the scanning range, the scanning position of the laser beam can be detected over the entire scanning range. Disappear. On the other hand, when the condensing lens 20 is arranged outside the scanning range as in the present embodiment, the scanning position of the laser beam can be properly detected for the entire scanning range.

  An optical filter 19 is disposed between the scanning range and the photodetector 21, and the light diffused by the wavelength conversion member 18 is selectively transmitted by the optical filter 19. Thereby, since it can suppress that the light which does not go through the wavelength conversion members 18, such as external light, injects into the photodetector 21, the scanning position of light can be detected accurately.

  The controller 201 controls the optical deflector 16 based on the detection signal of the photodetector 21 so that the scanning state of the laser light with respect to the incident surface 18a of the wavelength conversion member 18 becomes a predetermined scanning state. Specifically, as described with reference to FIGS. 7A to 8B, the controller 201 makes the scanning state appropriate when the scanning state of the laser beam deviates from the predetermined scanning state. The optical deflector 16 is controlled. Further, the controller 201 appropriately maintains the operating frequency of the optical deflector 16 as described with reference to FIG. In this way, when the optical deflector 16 is controlled so that the scanning state of the laser light becomes a predetermined scanning state, for example, the laser light sources 11a to 11c and the optical deflector 16 are synchronized and projected in the target region. It is possible to accurately set the light turn-off position and the light turn-on position for spot illumination.

  The controller 201 acquires the fall amount ΔA as a parameter value corresponding to the deterioration of the wavelength conversion member 18 based on the detection signal of the photodetector 21, and the state of the wavelength conversion member 18 based on the acquired fall amount ΔA. Determine. Accordingly, as described with reference to FIGS. 10A to 11, the abnormality of the wavelength conversion member 18 can be detected, and measures such as stopping the lighting of the laser light sources 11 a to 11 c according to the detection of the abnormality are performed. Can take.

<Modification 1>
In the above embodiment, the reflective wavelength conversion member 18 is used. On the other hand, in the first modification, the transmission type wavelength conversion member 18 is used. In the transmissive wavelength conversion member 18, the substrate 101 shown in FIG. 2A is formed of a material having excellent light transmittance, and the reflective film 102 is omitted. The laser light is incident from the lower surface (Z-axis negative surface) of the substrate 101 opposite to the phosphor layer 103.

  12A and 12B are a side view and a plan view, respectively, showing the configuration of the light projecting device 1 according to the first modification.

  12A and 12B, the tilt angle of the mirror 16a is adjusted so that the wavelength conversion member 18 can be irradiated with laser light. The diffused light including the light in the blue wavelength band and the light in the yellow wavelength band is emitted from the wavelength conversion member 18 by the laser light applied to the wavelength conversion member 18 on the Z axis positive side and the Z axis negative side of the wavelength conversion member 18. It occurs in both. Diffused light generated on the Z axis positive side of the wavelength conversion member 18 is projected onto the target area by the projection optical system 3 as in the above embodiment.

  The optical filter 19, the condensing lens 20, and the photodetector 21 are configured in the same manner as in the above embodiment, and are disposed outside the scanning range in the scanning direction of the laser light on the incident surface 18a, as in the above embodiment. ing. Here, the optical filter 19, the condensing lens 20, and the photodetector 21 are arranged on the Z-axis negative side of the wavelength conversion member 18. With this configuration, the photodetector 21 receives light in the yellow wavelength band diffused to the Z axis negative side of the wavelength conversion member 18. Therefore, also in the first modification, the scanning position of the laser beam on the incident surface 18a of the wavelength conversion member 18 can be detected for the entire scanning range by the detection signal of the photodetector 21. Therefore, the light scanning position can be detected with high accuracy.

  The optical filter 19, the condenser lens 20, and the photodetector 21 may be disposed on the Z axis positive side of the wavelength conversion member 18. In this case, the photodetector 21 receives light in the yellow wavelength band diffused to the Z axis positive side of the wavelength conversion member 18. Thus, when the optical filter 19, the condensing lens 20, and the photodetector 21 are arranged on the Z-axis positive side of the wavelength conversion member 18, particularly from the Z-axis negative side of the wavelength conversion member 18, There is no need to produce diffuse light in the yellow wavelength band. Therefore, in this case, in the wavelength conversion member 18, the substrate 101 shown in FIG. 2A is formed of a material having excellent light transmittance, and the reflective film 102 transmits light in the blue wavelength band, and in the yellow wavelength band. It may be configured by changing to a dichroic film that reflects light. Thereby, the light of the yellow wavelength band taken in by the projection optical system 3 can be enhanced.

  However, when the optical filter 19, the condenser lens 20, and the photodetector 21 are arranged on the positive side of the Z axis of the wavelength conversion member 18, the optical filter is applied to the diffused light from the wavelength conversion member 18 toward the projection optical system 3. 19 and the condensing lens 20 are easily hooked, and the arrangement of these members becomes difficult. Therefore, from this point, the optical filter 19, the condensing lens 20, and the photodetector 21 are arranged on the Z-axis negative side of the wavelength conversion member 18 as shown in FIGS. 12 (a) and 12 (b). That is preferable.

<Modification 2>
In the above embodiment, the optical deflector 16 has a configuration in which the mirror 16a is rotated about one axis by the rotation axis L1. On the other hand, in the second modification, the optical deflector 16 is configured so that the mirror 16a can rotate about two rotation axes orthogonal to each other. That is, the optical deflector 16 of the second modification causes the laser light to scan two-dimensionally on the incident surface 18 a of the wavelength conversion member 18.

  In the second modification, since the mirror 16a can be driven in two axes, the scanning trajectory of the laser beam on the incident surface 18a of the wavelength conversion member 18 is different from that in the above embodiment. In the second modification, as shown in FIG. 13A, a plurality of scanning lines LN1 to LN3 are set on the incident surface 18a, and accordingly, the size of the beam spot that scans the incident surface 18a is the same as that in the above embodiment. Compared to the Y-axis direction.

  The scanning range of the second modification has a spread in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction). The horizontal direction is the main scanning direction of the laser light on the incident surface 18a, and the vertical direction is the sub-scanning direction of the laser light on the incident surface 18a. When scanning starts from the upper left of the scanning range, the beam spot is scanned in the negative direction of the X axis along the scanning line LN1, and then scanned in the positive direction of the X axis along the scanning line LN2, to the scanning line LN3. Along the negative direction of the X-axis, and is positioned at the lower right of the scanning range. Thereafter, the beam spot is scanned in the positive direction of the X axis along the scanning line LN2, and returned to the upper left of the scanning range.

  As shown in FIG. 13A, the optical filter 19, the condensing lens 20, and the photodetector 21 are configured in the same manner as in the above embodiment, and in the horizontal scanning direction on the incident surface 18a, as in the above embodiment. Are arranged outside the horizontal scanning range. Further, these configurations are arranged at the end of the vertical scanning range in the vertical scanning direction on the incident surface 18a. Specifically, the optical filter 19, the condensing lens 20, and the photodetector 21 are arranged on the extension line of the uppermost scanning line LN1.

  FIG. 13B is a graph schematically showing the relationship between the scanning position and the amount of light received by the light 32 b in the yellow wavelength band received by the photodetector 21. In the graph, curves C11 to C13 correspond to the scanning lines LN1 to LN3, respectively.

  As in the above embodiment, the amount of light received by each scanning line is minimized at the position P11 farthest from the photodetector 21 in the horizontal scanning direction, and the position of each scanning line is measured at the position P12 closest to the photodetector 21 in the horizontal scanning direction. Received light is maximized. Therefore, in each scanning line, the laser light irradiation position in the horizontal scanning direction can be grasped as in the above embodiment, so that the light scanning position in the horizontal direction can be detected with high accuracy.

  Further, since the photodetector 21 is disposed at the end of the scanning range in the vertical direction, the curves C11 to C13 are arranged so that the amount of received light decreases in this order. Therefore, by determining the magnitude of the detection signal of the photodetector 21, it is possible to grasp which scanning line the laser beam is scanning. Further, similarly to the above-described embodiment, it is possible to control the operating frequency of the optical deflector 16 and the offset of the scanning range.

  Further, due to aging degradation of the optical deflector 16, the swing width of the mirror 16a in the vertical scanning direction may be reduced. In this case, the interval between the three scanning lines LN1 to LN3 in the vertical scanning direction is narrowed. As a result, in the graph shown in FIG. 13B, the interval between the curve C11 and the curve C12, and the curve C12 and the curve C13 The interval of becomes shorter. Therefore, by comparing the detection signals of the photodetector 21 obtained by scanning each scanning line, it can be understood how much the width of the scanning range in the vertical scanning direction is narrowed. The controller 201 assigns the drive signal in the vertical direction to the mirror drive circuit 203 so that the difference in detection signal based on each scan line becomes a desired difference at a predetermined horizontal scan position (for example, neutral position). Control to increase the width. By this control, the scanning range in the vertical scanning direction can be adjusted to a desired width.

  Also in the second modification example, as in the above-described embodiment, when a part of the wavelength conversion member 18 is reduced or missing, a part of the received light amount of the curves C11, C12, and C13 is reduced, so that the wavelength conversion member 18 The state can be determined.

<Other changes>
The configurations of the light projecting device 1 and the light source device 2 can be variously changed in addition to the configurations shown in the embodiment and the modified examples.

  For example, in the above-described embodiment and modification, the number of laser light sources arranged in the light source device 2 is not limited to three, and may be two or less or four or more.

  In the above embodiment and the modification, the optical system of the light source device 2 may be configured such that a plurality of beam spots are arranged on the incident surface 18a of the wavelength conversion member 18 in a direction perpendicular to the scanning direction.

  Moreover, in the said embodiment and modification, the kind of fluorescent substance particle 103a contained in the fluorescent substance layer 103 of the wavelength conversion member 18 does not necessarily need to be one kind, for example, the laser beam from the laser light sources 11a-11c The phosphor layer 103 may include a plurality of types of phosphor particles 103a that generate fluorescence having different wavelengths. In this case, light of a predetermined color is generated by the diffused light of the fluorescence generated from each kind of phosphor particles 103a and the diffused light of the laser light that has not been wavelength-converted by the phosphor particles 103a.

  In the above embodiment, the optical filter 19 may be installed on the light receiving surface of the photodetector 21 or may be formed integrally with the condenser lens 20.

  In the above embodiment, the scanning direction of the projection light in the target area is not necessarily the horizontal direction, and the vertical direction may be the scanning direction of the projection light depending on the required irradiation conditions.

  Further, the controller 201, the laser drive circuits 202a to 202c, the mirror drive circuit 203, the signal processing circuit 204, and the interface 205 may not be integrated with the light source device 2.

  In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

DESCRIPTION OF SYMBOLS 1 ... Projection apparatus 2 ... Light source device 3 ... Projection optical system 11a-11c ... Laser light source 16 ... Optical deflector 18 ... Wavelength conversion member 18a ... Incident surface 19 ... Optical filter 20 ... Condensing lens (condensing member)
21 ... Photodetector 201 ... Controller

Claims (7)

A laser light source;
A wavelength conversion member that converts the wavelength of the laser light emitted from the laser light source into another wavelength and diffuses the wavelength-converted light;
An optical deflector that scans the laser light emitted from the laser light source on an incident surface of the wavelength conversion member;
Light that is disposed outside the scanning range on the incident surface in the scanning direction of the laser light on the incident surface, receives light diffused by the wavelength conversion member, and outputs a detection signal corresponding to the amount of light received A detector,
A light source device characterized by that. The light source device according to claim 1,
A condensing member that is disposed between the scanning range and the photodetector and condenses the light diffused by the wavelength conversion member on a light receiving surface of the photodetector;
A light source device characterized by that. The light source device according to claim 1 or 2,
An optical filter disposed between the scanning range and the photodetector and transmitting light diffused by the wavelength conversion member;
A light source device characterized by that. In the light source device according to any one of claims 1 to 3,
A controller that controls the optical deflector based on a detection signal of the photodetector so that a scanning state of the laser light with respect to the incident surface of the wavelength conversion member is a predetermined scanning state;
A light source device characterized by that. In the light source device according to any one of claims 1 to 4,
A controller that acquires a parameter value corresponding to deterioration of the wavelength conversion member based on a detection signal of the photodetector, and that determines a state of the wavelength conversion member based on the acquired parameter value;
A light source device characterized by that. The light source device according to any one of claims 1 to 5,
The optical deflector causes the laser light emitted from the laser light source to scan two-dimensionally on the incident surface of the wavelength conversion member,
The photodetector is disposed outside the scanning range on the incident surface in the main scanning direction of the laser light on the incident surface.
A light source device characterized by that. The light source device according to any one of claims 1 to 6,
A projection optical system for projecting the light diffused by the wavelength conversion member,
A light projection device characterized by that.

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