WO2018150942A1

WO2018150942A1 - Light source device and light projecting device

Info

Publication number: WO2018150942A1
Application number: PCT/JP2018/003935
Authority: WO
Inventors: 博隆上野
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-02-15
Filing date: 2018-02-06
Publication date: 2018-08-23
Also published as: JPWO2018150942A1; JP7065267B2

Abstract

Provided are a light source device capable of detecting correctly and with high precision the state of a deflector which causes light to scan across a wavelength converting member, and a light projecting device provided with the same. A light source device (2) is provided with a laser light source, a wavelength converting member (15), an optical deflector (14), and a position detector (19). The laser light source emits laser light. The wavelength converting member (15) converts the wavelength of the laser light into another wavelength, and diffuses the wavelength-converted laser light. The optical deflector (14) causes the laser light to scan in at least one dimension on a surface of incidence of the wavelength converting member (15). The position detector (19) receives laser light that has been specularly reflected at the surface of incidence of the wavelength converting member (15), for the entire scanning range at the surface of incidence of the wavelength converting member (15), and outputs a detection signal corresponding to a light reception position.

Description

Light source device and light projecting device

The present disclosure 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 of 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.

In Patent Document 1 below, the light emitting surface of a phosphor (wavelength conversion member) is scanned with a laser beam by a swingable micromirror to generate an optical image on the light emitting surface, and the generated optical image is converted into an optical system. A vehicle headlamp to be projected onto a road is described. In this vehicle headlamp, an optical sensor is arranged at a position where the laser beam reflected by the light emitting surface is detected at a predetermined swing position of the micromirror, and the position and movement of the micromirror are detected by a signal from the optical sensor. Is done.

Special table 2016-528671

In the above-mentioned Patent Document 1, since the reflected light is incident on the optical sensor only when the tilt angle of the micromirror is at a predetermined angle, the operation state of the micromirror is properly detected in a range other than this angle. I can't. For example, when the reflected light does not enter the optical sensor because the micromirror does not properly respond to the drive signal, the configuration of Patent Document 1 immediately detects this based on the output from the optical sensor. I can't.

In view of such a problem, the present disclosure provides a light source device capable of accurately and accurately detecting a state of a deflector that scans light with respect to a wavelength conversion member, and a light projecting device using the light source device. Objective.

The first aspect of the present disclosure relates to a light source device. The light source device according to the first aspect includes a laser light source, a wavelength conversion member, an optical deflector, and a position detector. The laser light source emits laser light. The wavelength conversion member has an incident surface on the optical path of the laser light, converts the wavelength of the laser light to another wavelength, generates converted light, and diffuses the converted light. The optical deflector scans the laser beam at least one dimension on the incident surface of the wavelength conversion member. The position detector receives the laser beam specularly reflected on the incident surface of the wavelength conversion member with respect to all scanning ranges on the incident surface and outputs a detection signal corresponding to the light receiving position of the laser beam. Here, regular reflection means that excitation light is reflected at the same angle as the incident angle without being absorbed and diffused by the phosphor. Regular reflection is also called direct reflection.

According to the light source device according to this aspect, the detection signal is output from the position detector for the entire scanning range on the incident surface of the wavelength conversion member. Therefore, by monitoring this detection signal, the operation state of the optical deflector can be detected in the entire scanning range. Therefore, the operation state of the optical deflector can be detected accurately and with high accuracy.

The second aspect of the present invention relates to a light projecting device. The light projecting device according to the second 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 this aspect, the same effect as in the first aspect can be achieved.

As described above, according to the light source device and the light projecting device according to the present disclosure, it is possible to accurately and accurately detect the state of the deflector that scans the wavelength conversion member with light.

The effects or significance of the invention according to the present disclosure (hereinafter referred to as the present invention) will be further clarified by 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.

FIG. 1 is a perspective view illustrating a configuration of a light projecting device according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a configuration of the light projecting device according to the first embodiment. FIG. 3A is a perspective view showing the configuration of the optical deflector according to the first embodiment. FIG. 3B is a perspective view in which a part of the optical deflector according to the first embodiment is cut away. FIG. 4A is a side view schematically showing the configuration of the wavelength conversion member according to the first embodiment. FIG. 4B is a plan view schematically showing the configuration of the wavelength conversion member according to the first embodiment. FIG. 5A is a diagram for explaining a configuration of a position detector and a method for generating a position detection signal according to the first embodiment. FIG. 5B is a cross-sectional view schematically showing the configuration of the position detector according to the first embodiment. FIG. 6A is a diagram schematically illustrating the movement of the beam spot on the incident surface of the wavelength conversion member according to the first embodiment. FIG. 6B is a diagram schematically showing the movement of the specularly reflected light spot on the position detector when the beam spot moves as shown in FIG. 6A according to the first embodiment. FIG. 7 is a circuit block diagram illustrating a main circuit configuration of the light source device according to the first embodiment. FIG. 8A is a diagram schematically illustrating the movement of the beam spot on the incident surface of the wavelength conversion member when the mirror swing angle is lower than a predetermined swing angle according to the first embodiment. FIG. 8B is a diagram schematically showing the movement of the specularly reflected light spot on the light receiving surface of the position detector when the beam spot is moved as shown in FIG. 8A according to the first embodiment. FIG. 9 is a timing chart for explaining an interpolation method of the position detection signal when the laser light source is controlled to be extinguished during a predetermined period according to the first embodiment. FIG. 10A is a flowchart illustrating threshold value setting processing for detecting an abnormality of the wavelength conversion member according to the first embodiment. FIG. 10B is a flowchart illustrating a process for detecting an abnormality of the wavelength conversion member according to the first embodiment. FIG. 11A is a partial cross-sectional view illustrating a configuration of a light projecting device according to a first modification of the first embodiment. FIG. 11B is a partial cross-sectional view illustrating a configuration of a light projecting device according to a second modification of the first embodiment. FIG. 12A is a partial cross-sectional view illustrating a configuration of a light projecting device according to a third modification of the first embodiment. FIG. 12B is a partial cross-sectional view illustrating a configuration of a light projecting device according to a third modification of the first embodiment. FIG. 13 is a perspective view showing a configuration of an optical deflector according to the second embodiment. FIG. 14A is a perspective view in which a part of the optical deflector according to the second embodiment is cut away. FIG. 14B is a perspective view in which a part of the optical deflector according to the second embodiment is cut away. FIG. 15A is a diagram schematically illustrating the movement of the beam spot on the incident surface of the wavelength conversion member according to the second embodiment. FIG. 15B is a diagram schematically illustrating the movement of the specularly reflected light spot on the position detector when the beam spot moves as illustrated in FIG. 6A according to the second embodiment. FIG. 16 is a cross-sectional view illustrating a configuration of a light projecting device according to the third embodiment.

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 X-axis direction and the Y-axis direction are the width direction and the depth direction of the light projecting device, respectively, and the Z-axis direction is the height direction of the light projecting device. In the following first and second embodiments, the positive Z-axis direction is the light projection direction in the light projecting device.

<First Embodiment>
FIG. 1 is a perspective view showing a configuration of a light projecting device 1 according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a configuration of the light projecting device 1 according to the first embodiment. FIG. 2 shows a cross-sectional view of the light projecting device 1 cut at a central position in the X-axis direction along a plane parallel to the YZ plane.

1 and 2, the light projecting device 1 includes a light source device 2 that generates light and a projection optical system 3 that projects the 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. Note that the projection optical system 3 does not necessarily have only two

lenses

3a and 3b, and may include other lenses and mirrors, for example. 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 has a configuration in which various members are installed on the base 11. Specifically, a laser light source 12, a collimator lens 13, an optical deflector 14, and a wavelength conversion member 15 are installed on the base 11 as a configuration for generating projection light. The collimator lens 13 is installed on the base 11 via the holder 16.

The laser light source 12 emits laser light in a blue wavelength band (for example, 450 nm) in the positive direction of the Z axis. The laser light source 12 is made of, for example, a semiconductor laser. The wavelength of the laser light emitted from the laser light source 12 can be changed as appropriate. Further, the laser light source 12 does not necessarily emit a laser beam having 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 lens 13 converts the laser light emitted from the laser light source 12 into parallel light. The position of the collimator lens 13 in the optical axis direction may be adjusted so that the laser light emitted from the laser light source 12 becomes convergent light.

The optical deflector 14 includes a mirror 17 and changes the traveling direction of the laser light that has passed through the collimator lens 13 by rotating the mirror 17 about the rotation axis L1. The incident surface of the mirror 17 is a plane. The mirror 17 is, for example, a high reflectance mirror in which a dielectric multilayer film is formed on a glass plate. In the neutral position, the mirror 17 is disposed so as to be inclined by a predetermined angle in a direction parallel to the YZ plane with respect to a plane parallel to the XZ plane. The rotation axis L1 of the mirror 17 is parallel to the YZ plane and tilted by a predetermined angle with respect to the Z-axis direction. The configuration of the optical deflector 14 will be described later with reference to FIGS. 3A and 3B.

The wavelength conversion member 15 is disposed at a position where the laser beam reflected by the mirror 17 is incident. The wavelength conversion member 15 is a rectangular plate-like member, and is installed on the base 11 so that the incident surface is parallel to the XY plane and the longitudinal direction is parallel to the X axis. As described above, when the mirror 17 rotates about the rotation axis L1, the wavelength conversion member 15 is scanned in the longitudinal direction by the laser light.

The wavelength conversion member 15 converts part of the incident laser light into a wavelength different from the blue wavelength band and diffuses it in the Z-axis direction. The other laser light that has not been wavelength-converted is diffused in the Z-axis direction by the wavelength conversion member 15. 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 first embodiment, the wavelength conversion member 15 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. The configuration of the wavelength conversion member 15 will be described later with reference to FIGS. 4A and 4B.

A circuit board 18 is installed on the lower surface of the base 11. A circuit for controlling the laser light source 12 and the optical deflector 14 is mounted on the circuit board 18. As shown in FIG. 1, the terminal portion of the circuit board 18 is exposed to the outside on the Y axis positive side of the base 11.

Furthermore, in the first embodiment, the position detector 19 is installed at a position for receiving laser light specularly reflected by the incident surface of the wavelength conversion member 15 (hereinafter referred to as “regular reflected light”). The position detector 19 is in a plane parallel to the XZ plane so that when the mirror 17 is in the neutral position, the central axis of the specularly reflected light is perpendicular to the incident surface of the position detector 19. It is installed on the base 11 in a state inclined by a predetermined angle in a direction parallel to the YZ plane.

The position detector 19 receives regular reflection light for all scanning ranges on the incident surface of the wavelength conversion member 15 and outputs a detection signal corresponding to the light receiving position. That is, the position detector 19 has a light receiving surface that is long in the X-axis direction so as to be able to receive regular reflection light for the entire scanning range on the incident surface of the wavelength conversion member 15.

Further, in the regular reflection optical path between the position detector 19 and the wavelength conversion member 15, for example, a band pass filter 31 that removes yellow light converted by the wavelength conversion member and transmits blue light that is regular reflection light; It is desirable to have a neutral density filter 32 for reducing regular reflection light.

The position detector 19 is made of, for example, PSD (Position Sensitive Detector). In addition, the position detector 19 may have a configuration in which a photo detector is arranged on an array, or may be an image pickup device such as a CCD (Charge-Coupled Device).

The configuration of the position detector 19 and the method of generating the position detection signal will be described later with reference to FIGS. 5A and 5B.

3A and 3B are a perspective view showing a configuration of the optical deflector 14 and a perspective view in which a part of the optical deflector 14 is cut away, respectively. FIG. 3B shows a cross section 3b obtained by cutting the optical deflector 14 shown in FIG. 3A along a plane including a straight line IIIB-IIIB passing through the central position in the y-axis direction of the optical deflector 14 along the xz plane. ing.

For convenience, FIGS. 3A and 3B newly show x, y, and z axes in order to explain the configuration of the optical deflector 14. Among these, the x axis is in the same direction as the X axis shown in FIGS. 1 and 2. The x, y, and z axes are obtained by rotating the X, Y, and Z axes shown in FIGS. 1 and 2 around the X axis by a predetermined angle. The y axis corresponds to the short direction of the optical deflector 14, and the z axis corresponds to the height direction of the optical deflector 14. Here, for convenience, the z-axis negative side is defined as the upper side of the optical deflector 14.

3A and 3B, the optical deflector 14 is configured to drive the mirror 17 using electromagnetic force. A component for electromagnetic driving is installed in the housing 101.

The housing 101 has a rectangular parallelepiped shape that is long in the x-axis direction. A rectangular recess 101a is formed on the upper surface of the housing 101 in plan view. The housing 101 has bosses 101b formed on the upper surfaces of the positive and negative edges of the x-axis. The two bosses 101b are disposed at an intermediate position of the housing 101 in the y-axis direction. The housing 101 is made of a metal material having high rigidity.

A frame-shaped leaf spring 102 is installed on the upper surface of the housing 101. The leaf spring 102 has a frame portion 102a, a support portion 102b, two beam portions 102c, and two holes 102d.

Two beam portions 102c are formed so as to extend in parallel to the y-axis direction from the frame portion 102a at an intermediate position in the x-axis direction, and the frame portion 102a and the support portion 102b are connected by these beam portions 102c. . The support portion 102b is rectangular in plan view, and two beam portions 102c are connected to the support portion 102b at an intermediate position in the x-axis direction of the support portion 102b. Similarly to the boss 101b, the x-axis positive side hole 102d is circular in plan view, and the x-axis negative side hole 102d is long in the x-axis direction in plan view. The leaf spring 102 is symmetric in the y-axis direction, and is symmetric in the x-axis direction except for the two holes 102d. The leaf spring 102 is integrally formed of a flexible metal material.

The two holes 102d are provided at positions corresponding to the two bosses 101b, respectively. With the boss 101b fitted in the hole 102d, the leaf spring 102 is fixed to the upper surface of the housing 101 by the four screws 103. The mirror 17 is fixed to the upper surface of the support portion 102b with an adhesive or the like. The mirror 17 is substantially square in plan view. The axis connecting the two beam portions 102c is the rotation axis L1 of the mirror 17.

The laser light from the laser light source 12 is incident on the center position of the mirror 17. That is, the laser light from the laser light source 12 enters the mirror 17 so that the rotation axis L1 and the central axis of the laser light intersect.

The coil 104 is mounted on the lower surface of the support portion 102b. The coil 104 circulates in a shape with rounded rectangular corners in plan view. The coil 104 is installed on the lower surface of the support portion 102b so that the middle position of the long side coincides with the rotation axis L1. The coil 104, the support portion 102b, and the mirror 17 constitute a movable portion of the optical deflector 14.

Two sets of

magnets

105 and 106 are arranged so that the x-axis positive side and x-axis negative side portions of the coil 104 are sandwiched in the x-axis direction, respectively. Magnet 105 and magnet 106 are installed on yoke 107, and yoke 107 is installed on the bottom surface of recess 101 a of housing 101. The

magnets

105 and 106 are permanent magnets having a substantially uniform magnetic flux density on the magnetic pole surface.

The direction of the magnetic field generated by the x-axis

positive magnets

105 and 106 and the direction of the magnetic field generated by the x-axis

negative magnets

105 and 106 are the same. For example, the x-axis positive magnet 105 has the north pole facing the coil 104, and the x-axis negative magnet 105 has the south pole facing the coil 104. The x-axis positive magnet 106 has the south pole facing the coil 104, and the x-axis negative magnet 106 has the north pole opposed to the coil 104. By adjusting the magnetic pole (the direction of the magnetic field) in this way, when a drive signal (current) is applied to the coil 104, the drive force around the rotation axis L1 is excited in the coil 104. As a result, the mirror 17 rotates about the rotation axis L1. Although an electromagnetic optical deflector is used in the present embodiment, any of an electromagnetic type, a piezoelectric type, and an electrostatic type may be used as the optical deflector.

FIG. 4A is a side view schematically showing the configuration of the wavelength conversion member 15.

The wavelength conversion member 15 has a configuration in which a reflective film 202 and a phosphor layer 203 are laminated on the upper surface of a substrate 201.

The substrate 201 is made of, for example, silicon or aluminum nitride ceramic.

The reflective film 202 is configured by laminating a first reflective film 202a and a second reflective film 202b. The first reflective film 202a is, for example, a metal film such as Ag, an Ag alloy, or Al. The second reflection film 202b has a function of protecting the first reflection film 202a 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 are used.} , SiN, AlN, or other dielectric material. The reflective film 202 does not necessarily need to be composed of the first reflective film 202a and the second reflective film 202b, and may be a single layer or a structure in which three or more layers are laminated.

The phosphor layer 203 is formed by fixing phosphor particles 203a with a binder 203b. The phosphor particles 203a emit fluorescence in the yellow wavelength band when irradiated with laser light in the blue wavelength band emitted from the laser light source 12. As the phosphor particles 203a, for example, (Y _n Gd _1-n ) ₃ (Al _m Ga _1-m ) ₅ O ₁₂ : Ce (0.5 ≦ n ≦ 1, 0.5) having an average particle diameter of 1 μm to 30 μm. ≦ m ≦ 1) is used. Further, a transparent material mainly containing silsesquioxane such as polymethylsilsesquioxane is used as the binder 203b.

The phosphor layer 203 may further contain Al ₂ O ₃ fine particles having an average particle diameter of 0.1 to 10 μm and a thermal conductivity of 30 W / (m · K) as the _second particles. In this case, 2nd particle | grains are mixed by the ratio of 10 vol% or more and 90 vol% or less with respect to the fluorescent substance particle 203a. For example, as the second particles, silsesquioxane (refractive index 1.5) refractive index difference is large _Al 2 _{O 3} is a material of the binder 203b (refractive index 1.8) is used. With this configuration, the light scattering property inside the phosphor layer 203 can be improved, and the thermal conductivity of the phosphor layer 203 can be increased.

Furthermore, it is preferable to provide a void 203 c inside the phosphor layer 203. In the first embodiment, the phosphor layer 203 is provided with a void 203 c formed near the center of the phosphor layer 203 and a void 203 c formed near the interface between the reflective film 202.

Here, the void 203c formed inside the phosphor layer 203 is configured to have a higher density as it is closer to the reflective film 202. With this configuration, it is possible to more efficiently scatter laser light that has entered the inside and extract it from the light source device 2. In addition, since the void 203c formed near the interface with the reflective film 202 is in contact with the second reflective film 202b, which is a dielectric, it effectively scatters laser light and fluorescence while reducing energy loss due to the metal surface. Can be made.

The arrangement of the void 203c as described above is achieved by configuring the wavelength conversion member 15 using a phosphor paste in which phosphor particles 203a made of YAG: Ce and a binder 203b made of polysilsesquioxane are mixed. Can be easily formed. Specifically, the phosphor particles 203a and the second particles are formed on the substrate 201 (reflection film 202) using a phosphor paste in which polysilsesquioxane is mixed with a binder 203b in which an organic solvent is dissolved. Then, the organic solvent in the paste is vaporized by performing high-temperature annealing at about 200 ° C. At this time, since the organic solvent evaporated from the portion near the substrate 201 of the wavelength conversion member 15 is easily retained, the void 203c can be easily formed in the portion close to the substrate 201. By such a manufacturing method, the high-density void 203c can be easily formed in the vicinity of the reflective film 202.

The phosphor layer 203 further includes a filler 203d for increasing strength and heat resistance. The difference in refractive index between the filler 203d and the binder 203b is also set to be large, similar to the difference in refractive index between the phosphor particles 203a and the binder 203b.

The laser light emitted from the laser light source 12 is irradiated to the excitation region R1 shown in FIG. 4A, and is scattered and absorbed on the surface or inside of the phosphor layer 203. At this time, part of the laser light is converted into light in the yellow wavelength band by the phosphor particles 203 a and emitted from the phosphor layer 203. Further, 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 203 as light in the blue wavelength band. At this time, light in each wavelength band is scattered while propagating through the phosphor layer 203, and thus is emitted from the light emitting region R2 wider than the excitation region R1.

In addition, as described above, the phosphor layer 203 is configured such that the refractive index difference between the binder 203b and the phosphor particle 203a and the refractive index difference between the binder 203b and the filler 203d are both large, thereby scattering light. And propagation of light inside the phosphor layer 203 can be suppressed. As a result, light can be emitted from the light emitting region R2 that is slightly wider than the excitation region R1. In the first embodiment, the void 203c is further arranged in the phosphor layer 203 to enhance light scattering. As a result, the excitation region R1 and the light emission region R2 can be brought closer to each other.

FIG. 4B is a plan view schematically showing the configuration of the wavelength conversion member 15.

The wavelength conversion member 15 has a rectangular shape that is long in the X-axis direction in plan view. The wavelength conversion member 15 is scanned in the X-axis direction with a laser beam when the mirror 17 of the optical deflector 14 is rotated. In FIG. 4B, B1 indicates the beam spot of the laser beam. The beam spot B1 reciprocates on the incident surface 15a of the wavelength conversion member 15 in the width W1.

For example, a triangular wave-shaped drive signal (current) having an amplitude center at zero level is applied to the coil 104. Due to the driving force excited in the coil 104 by this driving signal, the mirror 17 together with the support portion 102b rotates around a neutral position with a predetermined rotation width. Thereby, the laser beam (beam spot B1) reflected by the mirror 17 reciprocates on the incident surface 15a of the wavelength conversion member 15 in the width W1.

The “neutral position” is the position of the mirror 17 when the drive signal (current) is not applied to the coil 104. In the configuration of the first embodiment, as shown in FIG. The position of the mirror 17 when the mirror 102b and the mirror 17 are not rotated in any direction about the rotation axis L1 and is in a state parallel to the xy plane.

In FIG. 4B, the reciprocation of the beam spot B1 is indicated by a straight arrow. However, since the laser light is incident on the wavelength conversion member 15 from an oblique direction, the actual movement locus of the beam spot B1 is X 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 axial center position.

The region of the beam spot B1 on the incident surface 15a corresponds to the excitation region R1 in FIG. 4A. While the beam spot B1 moves on the incident surface 15a of the wavelength conversion member 15, 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 B1 in the positive direction of the Z axis. Radiated.

The light in the two wavelength bands thus radiated is taken in by the projection optical system 3 shown in FIGS. 1 and 2 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.

In the configuration shown in FIG. 2, the active layer of the laser element mounted on the laser light source 12 is parallel to the XZ plane. For this reason, the beam shape of the laser light incident on the collimator lens 13 is an elliptical shape that is long in the Y-axis direction. As a result, as shown in FIG. 4B, the laser beam is irradiated onto the incident surface 15 a of the wavelength conversion member 15 with the beam spot B <b> 1 that is long in the Y-axis direction.

However, the shape of the beam spot B1 is not limited to an ellipse, and may be another shape that is long in the Y-axis direction. In this case, for example, the collimator lens 13 may have an optical action for adjusting the beam shape, or the reflecting surface of the mirror 17 is made a predetermined concave shape so that the beam shape is adjusted on the mirror 17. You may give an optical action.

FIG. 5A is a diagram for explaining a configuration of the position detector 19 and a method of generating a position detection signal. FIG. 5B is a cross-sectional view schematically showing the configuration of the position detector 19.

As shown in FIG. 5B, the position detector 19 has a structure in which a P-type resistance layer serving as a light-receiving surface and a resistance layer is formed on the surface of an N-type high-resistance silicon substrate. Electrodes X1 and X2 for outputting a lateral photocurrent are formed on the resistance layer on the front surface side, and a common electrode X3 is formed on the resistance layer on the back surface side. The photocurrent flowing into the electrodes X1 and X2 is output from the

terminals

19b and 19c.

Next, a method for calculating the irradiation position in the position detector 19 will be described. When the light receiving surface 19a of the position detector 19 is irradiated with specular reflection light (regular reflection light spot RB1), an electric charge proportional to the amount of light is generated at the irradiation position. This charge reaches the resistance layer as a photocurrent, is divided in inverse proportion to the distance to each of the electrodes X1 and X2, and is output from the

terminals

19b and 19c connected to the electrodes X1 and X2.

Here, in the position detector 19, the photocurrent output from the

terminals

19b and 19c has a size divided in inverse proportion to the distance from the irradiation position of the regular reflection light to the electrodes X1 and X2. Therefore, it is possible to detect the irradiation position of the regular reflection light in the X-axis direction on the light receiving surface based on the current value of the photocurrent output from the

terminals

19b and 19c.

For example, assume that the specularly reflected light spot RB1 is irradiated to the position detector 19 at the position shown in FIG. 5A. In this case, the horizontal coordinate Px of the irradiation position with respect to the horizontal center position Lmx of the light receiving surface 19a is the current value of the photocurrent output from the electrodes X1 and X2, respectively Ix1, Ix2, and the horizontal electrode When the distance between X1 and X2 is Lx, it is calculated by the following equation.

Thus, by performing the calculation of Expression (1) based on the current values Ix1 and Ix2 of the photocurrent output from the

terminals

19b and 19c of the position detector 19, the specularly reflected light spot RB1 on the light receiving surface 19a is calculated. A position detection signal (coordinate Px) indicating the position can be calculated.

FIG. 6A is a diagram schematically showing the movement of the beam spot B1 on the incident surface 15a of the wavelength conversion member 15. FIG. FIG. 6B is a diagram schematically showing the movement of the regular reflection light spot RB1 on the light receiving surface 19a of the position detector 19 when the beam spot B1 moves as shown in FIG. 6A.

When the beam spot B1 moves on the incident surface 15a of the wavelength conversion member 15 as shown in FIG. 6A, the specularly reflected light spot RB1 moves on the light receiving surface 19a of the position detector 19 as shown in FIG. 6B. To do. Here, the lateral movement position of the specularly reflected light spot RB1 corresponds to each movement position in the X-axis direction of the beam spot B1 on the incident surface 15a on a one-to-one basis. When the beam spot B1 moves in the X axis direction within the range of the width W1, the specularly reflected light spot RB1 moves in the lateral direction on the light receiving surface 19a of the position detector 19 within the range of the width Lw.

Here, the position of the beam spot B1 on the incident surface 15a corresponds to the rotation angle of the mirror 17 in the optical deflector 14. Therefore, the lateral position of the specularly reflected light spot RB1 on the light receiving surface 19a of the position detector 19 with respect to the center position Lmx corresponds to the rotation angle of the optical deflector 14 with respect to the neutral position of the mirror 17. Therefore, not only the scanning position of the beam spot B1 on the incident surface 15a of the wavelength conversion member 15 but also the mirror 17 of the optical deflector 14 is detected by the position detection signal (coordinate Px) calculated based on the above formula (1). The rotation angle can also be detected.

In the first embodiment, based on the position detection signal (coordinate Px) acquired in this way, the optical deflector 14 is set so that the scanning state of the laser light with respect to the incident surface 15a of the wavelength conversion member 15 becomes a predetermined scanning state. Is controlled.

FIG. 7 is a circuit block diagram showing a main circuit configuration of the light source device 2.

As shown in FIG. 7, the light source device 2 includes a controller 301, a laser drive circuit 302, a mirror drive circuit 303, a position detection circuit 304, and an interface 305 as a circuit unit configuration. These circuits are mounted on the circuit board 18 shown in FIGS. A laser light source 12 is further installed on the circuit board 18. The circuit may be configured such that a part or all of each circuit is mounted on a circuit board different from the circuit board 18 and connected to the circuit on the circuit board 18 side with a cable.

The controller 301 includes an arithmetic processing circuit such as a CPU (Central Processing Unit) and a memory, and controls each unit according to a predetermined control program. The laser drive circuit 302 drives the laser light source 12 according to a control signal from the controller 301. The mirror drive circuit 303 drives the mirror 17 of the optical deflector 14 in accordance with a control signal from the controller 301.

The position detection circuit 304 performs the calculation of the above formula (1) based on the detection signal input from the position detector 19, that is, the current output from the

terminals

19b and 19c in FIGS. 5A and 5B. The position detection signal (coordinate Px) obtained by the calculation is output to the controller 301. The interface 305 is an input / output circuit for the controller 301 to transmit / receive signals to / from an external control circuit such as a vehicle-side control circuit.

The controller 301 monitors the scanning state of the laser beam with respect to the incident surface 15a of the wavelength conversion member 15 based on the position detection signal (coordinate Px) input from the position detection circuit 304, and determines whether the scanning state of the laser beam is appropriate as needed. Determine. And when the scanning state of the laser beam with respect to the incident surface 15a of the wavelength conversion member 15 deviates from a predetermined scanning state, the optical deflector 14 is controlled so that the scanning state becomes appropriate.

Hereinafter, a control example of the optical deflector 14 will be described.

FIG. 8A is a diagram schematically showing the movement of the beam spot B1 on the incident surface 15a of the wavelength conversion member 15 when the swing angle of the mirror 17 is lower than a predetermined swing angle. FIG. 8B is a diagram schematically showing the movement of the regular reflection light spot RB1 on the light receiving surface 19a of the position detector 19 when the beam spot B1 moves as shown in FIG. 8A.

For example, the rotation width of the mirror 17 according to the drive signal may be reduced from a predetermined rotation width due to, for example, deterioration of the optical deflector 14 over time. In this case, as shown in FIG. 8A, the movement width of the beam spot B1 on the incident surface 15a of the wavelength conversion member 15 is reduced by ΔW with respect to the predetermined width W1. Thus, when the movement width of the beam spot B1 decreases, the movement width of the regular reflection light spot RB1 on the light receiving surface 19a of the position detector 19 also decreases by ΔL from the predetermined width Lw.

In this case, the controller 301 sends the drive signal amplitude to the mirror drive circuit 303, that is, so that the movement width of the regular reflection light spot RB1 on the light receiving surface 19a of the position detector 19 becomes the predetermined width Lw. Control is performed to increase the amplitude of the drive signal having a triangular waveform centered on the zero level. By this control, the movement width of the beam spot B1 on the incident surface 15a of the wavelength conversion member 15 is matched with the predetermined width W1.

Further, depending on the frequency of the drive signal applied to the optical deflector 14, resonance may occur in the operation of the mirror 17. In this case, for example, the controller 301 measures the time required for the specularly reflected light spot RB1 to move between the boundaries on both sides of the width Lw, and based on the measurement result, the frequency of the reciprocating movement of the specularly reflected light spot RB1. (Period) is acquired. Then, the controller 301 determines that resonance occurs in the operation of the mirror 17 when the acquired frequency (cycle) greatly deviates from the frequency (cycle) of the drive signal of the optical deflector 14. Based on this determination result, the controller 301 changes the frequency of the drive signal so that the frequency (cycle) of the reciprocating movement of the regular reflection light spot RB1 matches the frequency of the drive signal.

The control based on the position detection signal in the controller 301 is not limited to the above control. For example, the controller 301 determines whether or not the movement width of the regular reflection light spot RB1 is shifted laterally from a predetermined width Lw based on the position detection signal, and the movement width of the regular reflection light spot RB1 is a predetermined width. You may perform control which adjusts the drive signal of the optical deflector 14 so that it may match with Lw. Alternatively, when the right-side movement width and the left-side movement width of the regular reflection light spot RB1 are different from the center position Lm, the drive signal of the optical deflector 14 is adjusted so that these movement widths are equal to each other. Control may be performed.

By the way, in the light source device 2, for example, by using a position detection signal as a synchronization signal between the laser and the optical deflector 14 in accordance with a control command from a control circuit on the vehicle side, the laser light source 12 in a predetermined section in the width W1. Control to turn off can be performed. For example, when a vehicle or oncoming vehicle is detected within the range of the headlamp on the vehicle side, control to turn off the position of the preceding vehicle or oncoming vehicle, light is applied only to the human area, etc. The light source device 2 is instructed from the vehicle side to control the so-called spot illumination, in which the region is not irradiated. This instruction is input to the controller 301 via the interface 305 in FIG. In this case, the controller 301 controls the laser drive circuit 302 to turn off the laser light source 12 in a predetermined section in the width W1 in accordance with an instruction from the vehicle side.

In this control, since the regular reflection light does not enter the light receiving surface 19a of the position detector 19 during the period when the laser light source 12 is turned off, the output of the position detection signal is interrupted during this period. Therefore, during the extinguishing period of the laser light source 12, it becomes impossible to detect the scanning state of the laser light on the incident surface 15 a of the wavelength conversion member 15 and the rotation state of the mirror 17.

In order to eliminate such an inconvenience, in the first embodiment, the process of interpolating the position detection signal during the non-lighting period of the laser light source 12 based on the position detection signal acquired during the lighting period of the laser light source 12 includes: This is performed in the controller 301.

FIG. 9 is a timing chart for explaining the interpolation method of the position detection signal when the laser light source 12 is controlled to be extinguished during a predetermined period. Drive signals output from the mirror drive circuit 303 and the laser drive circuit 302 are shown in the uppermost stage and the middle stage of FIG. 9, respectively, and a position detection signal output from the position detection circuit 304 is shown in the lowermost stage of FIG. It is shown. As described above, the optical deflector 14 is supplied with a triangular wave drive signal centered on the zero level as the amplitude.

As shown in FIG. 9, the position detection signal is output from the position detection circuit 304 only during the period (T1-T2, T4-T5, T7-T8, T10-T11) when the laser light source 12 is turned on. . In this case, the controller 301 interpolates similarly the drive signal in the non-lighting period as indicated by the dotted line in the lowermost stage, based on the slope and value of the output drive signal.

For example, the controller 301 obtains a straight line that overlaps the drive signal between the timings T1 and T2 based on the value of the drive signal at the timings T1 and T2 and the slope of the drive signal between the timings T1 and T2. Similarly, the controller 301 obtains a straight line that overlaps the drive signal between timings T4 and T5, a straight line that overlaps the drive signal between timings T7 and T8, and a straight line that overlaps the drive signal between timings T10 and T11. Then, the controller 301 obtains the intersection of these straight lines, and interpolates the position detection signal during the non-lighting period of the laser light source 12 with the line segments up to the intersections of the respective straight lines. The controller 301 executes the above-described control process based on the position detection signal after interpolation thus obtained.

The controller 301 executes a process of determining the state of the wavelength conversion member 15 based on a signal output from the position detector 19 in addition to the various processes described above.

That is, in the wavelength conversion member 15 shown in FIG. 4A, the thickness of the phosphor layer 203 may gradually decrease from the initial thickness due to factors such as continued irradiation with high-power laser light. When the thickness of the phosphor layer 203 is thus reduced, the excited fluorescence is reduced, and light of a desired color is not output. Further, when the phosphor layer 203 disappears completely in a part of the region, almost all of the light irradiated to the region is reflected laterally by the reflective film 202 and is not taken into the projection optical system 3.

As described above, when the thickness of the phosphor layer 203 decreases or the phosphor layer 203 disappears in a part of the region, the color of light generated in the part changes from a desired color, or the The light irradiated to the part is not taken into the projection optical system 3.

Here, when the thickness of the region of the phosphor layer 203 irradiated with the laser light decreases from the initial thickness, the amount of specularly reflected light toward the position detector 19 increases accordingly. When a part of the phosphor layer 203 disappears completely, the laser light applied to this part is reflected by the reflecting film 202 as it is and enters the position detector 19. Therefore, the state of the phosphor layer 203 in the wavelength conversion member 15 can be determined by monitoring the amount of specularly reflected light incident on the position detector 19.

Therefore, in the first embodiment, a light amount signal corresponding to the amount of specularly reflected light incident on the light receiving surface 19a of the position detector 19 is acquired from the signal output from the position detector 19, and the acquired light amount signal is obtained. Based on this, the state of the wavelength conversion member 15 is determined.

Here, the light quantity signal is acquired as a signal obtained by adding the current values Ix1 and Ix2 of the photocurrent output from the

terminals

19b and 19c shown in FIGS. 5A and 5B. Therefore, the position detection circuit 304 shown in FIG. 7 further executes a calculation process for calculating the light amount signal by adding the current values Ix1 and Ix2 of the photocurrent, and the light amount signal acquired by the calculation process is converted to the controller as needed. A configuration for outputting to 301 is also provided.

The controller 301 determines whether or not there is an abnormality in the wavelength conversion member 15 based on the light quantity signal thus acquired. Specifically, the controller 301 determines that an abnormality has occurred in the phosphor layer 203 of the wavelength conversion member 15 when the light amount signal exceeds a predetermined threshold value.

However, since the output of the laser light source 12 gradually decreases due to aging, the amount of specularly reflected light received by the position detector 19 also decreases accordingly. For this reason, the threshold value to be compared with the light amount signal needs to be gradually lowered according to the aging deterioration of the laser light source 12. Therefore, the controller 301 executes processing for updating the threshold value to be compared with the light amount signal based on the total lighting time of the laser light source 12.

FIG. 10A is a flowchart showing a threshold value Dth setting process for detecting an abnormality of the wavelength conversion member 15.

When the light source device 2 is activated, the controller 301 starts measuring the total activation time T of the laser light source 12 (S11). Here, the total activation time T is the total activation time of the laser light source 12 after the laser light source 12 is first activated. The total activation time T is measured only during a period in which the laser light source 12 is in a lighting state after the light source device 2 is activated, and is not measured in a period in which the laser light source 12 is in a non-lighting state.

Next, the controller 301 determines whether or not the total activation time T has reached a preset update time Tc (S12). When the total activation time T reaches the update time Tc (S12: YES), the controller 301 updates the threshold value Dth (S13). When the total activation time T has not reached the update time Tc (S12: NO), the controller 301 skips step S13. The controller 301 repeatedly executes the processes of steps S11 to S13 until the light source device 2 is powered off (S14: YES). When the power supply to the light source device 2 is shut off (S14: YES), the controller 301 ends the measurement of the total activation time T and stores the total activation time T after measurement in the internal memory (S15).

Note that a plurality of update times Tc in step S12 are held in the controller 301 in advance. For example, when four update times Tc are held, the controller 301 first decreases the threshold Dth at the timing when the total activation time T reaches the first update time Tc, and then the total activation time T is The threshold value Dth is further lowered at the timing when the next update time Tc is reached. Thereafter, similarly, the controller 301 decreases the threshold value Dth every time the total activation time T reaches the third and fourth update times Tc.

Here, the threshold value Dth of each update time Tc is set in consideration of, for example, a change in emission power over time, which can occur normally in the laser light source 12. That is, the output power at each update time Tc is set based on a standard change over time, and a predetermined ratio (for example, 1....) Is set to the value of the light amount signal that can be generated when the laser light is emitted with the set output power. A value obtained by multiplying 5) is set as the threshold value Dth at the update time Tc. The threshold value Dth at each update time Tc is held in the internal memory of the controller 301 in advance.

FIG. 10B is a flowchart showing a process for detecting an abnormality of the wavelength conversion member 15 using the threshold value Dth set by the process of FIG. 10A.

When the controller 301 acquires the light amount signal Da from the position detection circuit 304 (S21), the controller 301 determines whether or not the acquired light amount signal Da exceeds the threshold value Dth (S22). Here, when the light amount signal Da exceeds the threshold value Dth (S22: YES), the controller 301 ends the lighting of the laser light source 12, and sets a flag indicating that an abnormality has occurred in the wavelength conversion member 15 (S23). ). In this case, the controller 301 may output a notification signal indicating that an abnormality has occurred in the wavelength conversion member 15 to an external control circuit (for example, a control circuit on the vehicle side) via the interface 305.

On the other hand, when the light quantity signal Da does not exceed the threshold value Dth (S22: NO), the controller 301 skips step S23. The controller 301 repeatedly executes the processes of steps S21 to S23 until the power to the light source device 2 is shut off (S24: YES). When the power supply to the light source device 2 is shut off (S24: YES), the controller 301 ends the abnormality detection process of the wavelength conversion member 15.

<Effect of the first embodiment>
As described above, according to the first embodiment, the following effects are exhibited.

As described with reference to FIGS. 6A and 6B, a detection signal is output from the position detector 19 for the entire scanning range (width W1) on the incident surface 15a of the wavelength conversion member 15. Therefore, by monitoring this detection signal, the operation state of the optical deflector 14 can be detected in the entire scanning range (width W1). Therefore, the operating state of the optical deflector 14 can be detected accurately and with high accuracy.

Further, by having the band pass filter 31, it becomes possible to detect signals more accurately by removing unnecessary yellow light as signal light, and by having the neutral density filter 32, the signal light is not saturated. It is possible to adjust the signal amount.

As described with reference to FIGS. 8A and 8B, the controller 301 changes the scanning state of the laser light on the incident surface 15 a of the wavelength conversion member 15 to a predetermined scanning state based on the detection signal from the position detector 19. Thus, the optical deflector 14 is controlled. Thereby, even when the operation of the optical deflector 14 is deteriorated due to aging deterioration or the like, the scanning state of the laser light with respect to the incident surface 15a of the wavelength conversion member 15 can be adjusted to a predetermined scanning state. It can also be used as a synchronizing signal between the laser light source 12 and the optical deflector 14 for determining the lighting position for illumination.

As described with reference to FIG. 9, when the disappearance period occurs in the detection signal from the position detector 19 because the laser light source 12 is in the non-lighting state, the controller 301 disappears based on the detection signal of the lighting period. The detection signal for the period is interpolated, and the optical deflector 14 is controlled based on the detection signal after the interpolation. Thereby, even when the laser light source 12 is controlled not to be turned on, such as spot irradiation, the scanning state of the laser light with respect to the incident surface 15a of the wavelength conversion member 15 can be adjusted to a predetermined scanning state.

As described with reference to FIG. 10A and FIG. 10B, the controller 301 outputs a light amount signal Da corresponding to the amount of laser light (regular reflection light) regularly reflected on the incident surface 15 a of the wavelength conversion member 15 from the position detector 19. Is obtained based on the obtained signal, and the state of the wavelength conversion member 15 is determined based on the obtained light quantity signal Da. Thereby, the abnormality of the wavelength conversion member 15 can be further detected based on the detection signal from the position detector 19 and the controller 301 can appropriately take measures such as stopping the lighting of the laser light source 12.

<Modified example of the first embodiment>
In the light projecting device 1, the configuration for detecting the specularly reflected light can be variously changed in addition to the configuration shown in the first embodiment.

(First change example)
For example, as illustrated in FIG. 11A, in the light source device 2, the position detector 19 is installed on the circuit board 18, and the specularly reflected light that is specularly reflected by the incident surface 15 a of the wavelength conversion member 15 is mirror 20 (light guide member). ) May be guided to the position detector 19. In this case, the base 11 is provided with a hole 11 a for guiding the specularly reflected light reflected by the mirror 20 to the position detector 19. In this configuration, since the position detector 19 is mounted on the circuit board 18, it is not necessary to separately connect the position detector 19 and the circuit board 18 with a cable or the like. Therefore, the configuration of the circuit system can be simplified.

(Second modification)
In the configuration of FIG. 11A, for example, as shown in FIG. 11B, the condensing lens 21 is further attached to the base 11 as a condensing member for condensing the specularly reflected light on the light receiving surface 19a of the position detector 19. It may be installed. In this way, by condensing the specularly reflected light on the light receiving surface 19a, the size of the specularly reflected light spot RB1 can be further reduced. Thereby, the position detection accuracy of the regular reflection light spot RB1 on the light receiving surface 19a can be increased. For this reason, the scanning position of the beam spot B1 on the incident surface 15a of the wavelength conversion member 15 and the rotational position of the mirror 17 can be detected with higher accuracy.

(Third change example)
In this case, as shown in FIG. 12A, the specularly reflected light may be condensed on the light receiving surface 19 a of the position detector 19 by a concave mirror 22 instead of the condenser lens 21. In this configuration, the concave mirror 22 functions as a light guide member that guides the specularly reflected light to the position detector 19 and a light collecting member that condenses the specularly reflected light on the light receiving surface 19 a of the position detector 19. To do. According to this configuration, the condensing lens 21 can be omitted from the configuration of FIG. 11B, so that the configuration can be simplified.

Also in the configuration of the first embodiment, as shown in FIG. 12B, the specularly reflected light that is specularly reflected by the incident surface 15 a of the wavelength conversion member 15 is collected on the light receiving surface 19 a of the position detector 19. The condensing lens 23 may be installed on the base 11. Also in this case, since the position detection accuracy of the regular reflection light spot RB1 on the light receiving surface 19a can be increased, the scanning position of the beam spot B1 on the incident surface 15a of the wavelength conversion member 15 and the rotation position of the mirror 17 are further increased. It can be detected with high accuracy.

<Second Embodiment>
In the first embodiment, the optical deflector 14 is configured to rotate the driven part about one axis. On the other hand, in the second embodiment, the optical deflector 14 is configured so that the mirror 17 can rotate about two rotation axes orthogonal to each other.

In the second embodiment, since the mirror 17 can be driven in two axes, the scanning locus of the laser beam on the incident surface 15a of the wavelength conversion member 15 is different from that in the first embodiment. In the second embodiment, as described later, a plurality of scanning lines are set on the incident surface 15a of the wavelength conversion member 15, and accordingly, the size of the beam spot that scans the incident surface 15a of the wavelength conversion member 15 is It is narrowed down compared to the first embodiment. Other configurations of the light projecting device 1 and the light source device 2 are the same as those in the first embodiment.

Note that the size of the beam spot can be further reduced by adjusting the distance between the laser light source 12 and the collimator lens 13, the numerical aperture of the collimator lens 13, and the like. Further, the collimator lens 13 or the mirror 17 may be further provided with an optical action for adjusting the size and shape of the beam spot.

FIG. 13 is a perspective view showing the configuration of the optical deflector 14 according to the second embodiment. 14A and 14B are perspective views in which a part of the optical deflector 14 according to the second embodiment is cut away. 13, 14 </ b> A, and 14 </ b> B show the same x, y, and z axes as in FIGS. 3A and 3B. FIG. 14A shows a cross section 14a obtained by cutting the optical deflector 14 shown in FIG. 13 along a plane including a straight line XIVA-XIVA passing through the central position in the y-axis direction of the optical deflector 14 along the xz plane. Has been. In FIG. 14B, the optical deflector 14 shown in FIG. 13 in a plane parallel to the yz plane is parallel to the yz plane and includes a straight line XIVB-XIVB passing through the central position in the x-axis direction. A cut section 14b is shown.

Referring to FIG. 13, FIG. 14A, and FIG. 14B, the housing 111 has a rectangular parallelepiped shape that is long in the x-axis direction. On the upper surface of the housing 111, a rectangular recess 111a is formed in plan view. The housing 111 is made of a metal material having high rigidity.

A frame-shaped leaf spring 112 is installed on the upper surface of the housing 111. The leaf spring 112 has an outer frame portion 112a, an inner frame portion 112b, two beam portions 112c, a support portion 112d, and two beam portions 112e. Two beam portions 112c are formed so as to extend in parallel to the x-axis direction from the outer frame portion 112a at an intermediate position in the y-axis direction, and the outer frame portion 112a and the inner frame portion 112b are connected by these beam portions 112c. Has been. Further, at the intermediate position in the x-axis direction, two beam portions 112e are formed so as to extend in parallel to the y-axis direction from the inner frame portion 112b, and the inner frame portion 112b and the support portion 112d are formed by these beam portions 112e. It is connected.

The inner frame portion 112b has a contour with rounded rectangular corners in plan view, and two beam portions 112c are connected to the inner frame portion 112b at an intermediate position in the y-axis direction of the inner frame portion 112b. The support portion 112d has a rectangular outline in plan view, and two beam portions 112e are connected to the support portion 112d at an intermediate position in the x-axis direction of the support portion 112d. The leaf spring 112 has a symmetrical shape in the x-axis direction and the y-axis direction. The leaf spring 112 is integrally formed of a flexible metal material.

The plate spring 112 is fixed to the upper surface of the housing 111 with four screws 113 in a state where the outer frame portion 112 a is placed on the upper surface of the housing 111. The mirror 17 is fixed to the upper surface of the support portion 112d with an adhesive or the like. The mirror 17 is substantially square in plan view. The axis connecting the two beam portions 112e becomes the rotation axis L1 of the mirror 17 for scanning the laser beam in the longitudinal direction of the wavelength conversion member 15 as in the first embodiment. In addition, the axis connecting the two beam portions 112c becomes the rotation axis L2 of the mirror 17 for changing the scanning line of the laser beam in the wavelength conversion member 15.

Note that, as in the first embodiment, the laser light from the laser light source 12 enters the center position of the mirror 17. That is, the laser light from the laser light source 12 is incident on the mirror 17 so that the central axis of the laser light passes through the position where the rotation axes L1 and L2 intersect.

The coil 114 is attached to the lower surface of the support portion 112d. The coil 114 circulates in a shape with rounded rectangular corners in plan view. The coil 114 is installed on the lower surface of the support portion 112d so that the middle position of the long side coincides with the rotation axis L1. The coil 114, the support part 112 d, and the mirror 17 constitute a first movable part of the optical deflector 14.

Two sets of

magnets

115 and 116 are arranged so as to sandwich the coil 114 in the x-axis direction. The

magnets

115 and 116 are installed on the yoke 117, and the yoke 117 is installed on the bottom surface of the recess 111 a of the housing 111. The method of adjusting the magnetic poles of each set of

magnets

115 and 116 is the same as that of the

magnets

105 and 106 shown in FIGS. 3A and 3B.

Furthermore, a coil 118 is attached to the lower surface of the inner frame portion 112b. The coil 118 has the same shape as the inner frame portion 112b in plan view. The coil 118 is installed on the lower surface of the inner frame portion 112b so that the intermediate position of the short side coincides with the rotation axis L2. The coil 118 and the inner frame portion 112b constitute a second movable portion of the optical deflector 14.

Magnets 119 are arranged on the y-axis positive side and the y-axis negative side with respect to the coil 114, respectively. These magnets 119 are installed on the yoke 117. Further, these two magnets 119 are installed on the yoke 117 so that the magnetic poles facing the coil 118 are different from each other. The magnet 119 is a permanent magnet having a substantially uniform magnetic flux density on the magnetic pole surface.

By adjusting the magnetic poles of the two magnets 119 in this way, when a drive signal (current) is applied to the coil 118, the inner frame portion 112b rotates about the rotation axis L2, and according to the magnitude of the drive signal. The inner frame portion 112b is inclined by the angle. That is, the inner frame portion 112b is inclined from the neutral position shown in FIG. 13 by an angle at which the elastic restoring force generated in the beam portion 112c and the electromagnetic force excited by the coil 118 are balanced. At this time, the mirror 17 rotates together with the support portion 112d as the inner frame portion 112b rotates.

The support portion 112d rotates about the rotation axis L1 by applying a drive signal (current) to the coil 114 as in the configuration of FIGS. 3A and 3B. As the support portion 112d rotates, the mirror 17 rotates about the rotation axis L1. As described above, according to the optical deflector 14 of the second embodiment, the drive signal (current) is independently applied to the

coils

114 and 118, whereby the mirror 17 is individually moved about the rotation axes L 1 and L 2. Can be rotated.

FIG. 15A is a diagram schematically showing a scanning state of the laser light in the wavelength conversion member 15.

As shown in FIG. 15A, in the second embodiment, a plurality of scanning lines SL1 are set on the incident surface 15a of the wavelength conversion member 15. In the example of FIG. 15A, three scanning lines SL1 are set on the incident surface 15a. However, the number of scanning lines SL1 is not limited to this.

In addition, here, the beam spot B2 is narrowed down more than in the case of the first embodiment, and the shape of the beam spot B2 is adjusted to be circular. Such adjustment of the size and shape of the beam spot B2 is realized, for example, by giving the collimator lens 13 an optical action for converging the laser beam in a circular shape on the incident surface 15a of the wavelength conversion member 15. In addition, such an optical action may be imparted to the reflecting surface of the mirror 17. In this case, the reflecting surface of the mirror 17 is adjusted to a concave shape that can impart such an optical action to the laser light.

The laser beam spot B2 is positioned at the start position on the X-axis positive side of the second-stage scan line SL1 after the uppermost scan line SL1 is moved to the end position in the X-axis positive direction. Thereafter, the beam spot B2 is positioned at the X axis negative start position of the third scanning line SL1 after the second scanning line SL1 is moved to the end position in the X axis negative direction. Similarly, when the beam spot B2 moves to the end position on the X axis positive side of the third-stage scanning line SL1, the beam spot B2 is positioned at the start position of the second-stage scanning line SL1. Thereafter, the beam spot B2 is positioned at the start position on the X-axis negative side of the first-stage scan line SL1 after the second-stage scan line SL1 is moved to the end position in the X-axis negative direction. Thereafter, the same scanning is repeated for the three scanning lines SL1.

The movement of the beam spot B2 along the scanning line SL1 is performed by rotating the mirror 17 about the rotation axis L1 shown in FIG. The scan line SL1 is changed by rotating and tilting the mirror 17 about the rotation axis L2 shown in FIG. The optical deflector 14 is controlled by the control circuit mounted on the circuit board 18 of FIG. 1 so that the beam spot B2 scans the incident surface 15a of the wavelength conversion member 15 as described above.

Note that during the period in which the beam spot B2 moves from the end position of one scan line SL1 to the start position of the next scan line SL1, the emission of the laser light from the laser light source 12 is stopped. That is, the feed lines TL1 and TL2 in FIG. 15A indicate the movement trajectory of the beam spot B2 when laser light is emitted, and in actual control, the laser light source 12 in the feed lines TL1 and TL2 is shown. Is controlled to be turned off.

The laser beam scanning method for the incident surface 15a of the wavelength conversion member 15 is not limited to the above. For example, the incident surface 15a of the wavelength conversion member 15 is scanned with a laser beam so that the beam spot B2 jumps back and forth along each scanning line SL1 and then jumps to the start position of the next scanning line SL1. May be.

In the configuration of the second embodiment, the position detector 19 is replaced with a two-dimensional detection position detector 19 ′ shown in FIG. 15B so that the scanning position of the beam spot B2 in each scanning line SL1 can be detected. It is done. Here, in addition to the structure of the position detector 19 of the first embodiment, the position detector 19 ′ is a pair for outputting a photocurrent in the vertical direction to the resistance layer on the surface side shown in FIG. 5B. The electrodes are formed at the vertical edges, and the photocurrents flowing into these electrodes are output from the

terminals

19d and 19e, respectively.

In this position detector 19 ', the vertical coordinate Py of the irradiation position with the vertical center position Lmy of the light receiving surface 19a as a reference is calculated by the following equation. Here, Iy1 and Iy2 are current values of photocurrents output from the

terminals

19d and 19e, and Ly is a distance between the electrodes in the vertical direction.

Thus, the specularly reflected light spot RB2 on the light receiving surface 19a is obtained by performing the calculation of the equation (2) based on the current values Iy1 and Iy2 of the photocurrent output from the

terminals

19d and 19e of the position detector 19 ′. A position detection signal (coordinate Py) indicating the position in the vertical direction can be calculated. In this case as well, the position detection signal (coordinate Px) indicating the lateral position of the regular reflection light spot RB2 on the light receiving surface 19a can be calculated based on the above equation (1).

When the beam spot B1 moves on the incident surface 15a of the wavelength converting member 15 as shown in FIG. 15A, the specularly reflected light spot RB2 moves along the light receiving surface 19a of the position detector 19 ′ as shown in FIG. 15B. Move to. The position of the beam spot B1 on the incident surface 15a and the position of the specularly reflected light spot RB1 on the light receiving surface 19a correspond one-to-one. Therefore, also in this case, the position of the beam spot B1 on the incident surface 15a and the rotation position of the mirror 17 can be detected by the two types of position detection signals calculated by the above formulas (1) and (2).

In the second embodiment, the position detection circuit 304 acquires two types of position detection signals indicating the positions of the regular reflection light spot RB2 in the horizontal direction and the vertical direction based on the above formulas (1) and (2). These position detection signals are output to the controller 301 as needed. Further, the position detection circuit 304 adds the current values Ix1, Ix2, Iy1, and Iy2 of the photocurrents output from the terminals 19b to 19e to acquire a light amount signal, and outputs the acquired light amount signal to the controller 301.

The controller 301 determines the scanning state of the beam spot B2 for each scanning line SL1 based on the two types of position detection signals calculated by the above formulas (1) and (2), and the beam spot B2 performs predetermined scanning. The optical deflector 14 is controlled so as to appropriately scan the incident surface 15a of the wavelength conversion member 15 according to the line SL1. Further, the controller 301 performs wavelength conversion based on the light amount signal obtained by adding the current values Ix1, Ix2, Iy1, and Iy2 of the photocurrents output from the terminals 19b to 19e, as in the first embodiment. A process for detecting an abnormality of the member 15 is executed.

According to the configuration of the second embodiment, as in the first embodiment, from the position detector 19 with respect to the entire scanning range (width W1, scanning line SL1) on the incident surface 15a of the wavelength conversion member 15. Since the detection signal is output, the operation state of the optical deflector 14 can be detected in the entire scanning range (width W1, scanning line SL1) by monitoring the detection signal. Therefore, the operating state of the optical deflector 14 can be detected accurately and with high accuracy.

Further, according to the configuration of the second embodiment, since the wavelength conversion member 15 is scanned along the plurality of scanning lines SL1 with the more narrow beam spot B2, for example, white light is emitted on the light emitting region R2. The region where the light emission is stopped and the region where the white light is emitted can be set more finely. For this reason, when the white light generated from the light source device 2 is projected onto the target area by the projection optical system 3, the area where the white light projection is stopped or the area where the white light projection is performed on the target area is more Can be set in detail. Therefore, for example, when the light projecting device 1 is incorporated in the headlight of the vehicle, the white light irradiation region and the non-irradiation region are set more finely according to the position of the oncoming vehicle and the position of the pedestrian. be able to.

In the second embodiment, the configuration of each modified example shown in FIGS. 11A to 12B can be applied as appropriate.

<Third Embodiment>
In the first embodiment and the second embodiment, the reflective wavelength conversion member 15 is used. On the other hand, in the third embodiment, a transmissive wavelength conversion member 15 is used.

In the transmissive wavelength conversion member 15, the substrate 201 shown in FIG. 4A is formed of a material having excellent light transmittance, and the reflective film 202 transmits laser light in the blue wavelength band and reflects fluorescence in the yellow wavelength band. Changed to dichroic membrane. Laser light is incident from the lower surface of the substrate 201 opposite to the phosphor layer 203.

FIG. 16 is a cross-sectional view showing the configuration of the light projecting device 1 according to the third embodiment.

16, the wavelength conversion member 15 is installed on the base 11 so as to face the mirror 17 from the Y axis negative side. Further, the tilt angle of the mirror 17 is adjusted so that the wavelength conversion member 15 can be irradiated with laser light. A position detector 19 is installed at a position where the regular reflection light regularly reflected by the wavelength conversion member 15 is incident. Similar to the first embodiment, the position detector 19 is arranged so that the specularly reflected light can be received in the entire scanning range on the incident surface 15 a of the wavelength conversion member 15.

In the configuration of FIG. 16, the wavelength conversion member 15 is scanned with laser light as the mirror 17 rotates. By this scanning, diffused light in the yellow wavelength band and diffused light in the blue wavelength band are emitted from the Y axis negative side of the wavelength conversion member 15, and these diffused lights are taken into the

lenses

3 a and 3 b of the projection optical system 3. Thus, white light is emitted from the projection optical system 3. At this time, based on the detection signal output from the position detector 19, the controller 301 monitors the scanning state of the laser beam with respect to the incident surface 15a of the wavelength conversion member 15 as in the first embodiment. The controller 301 controls the optical deflector 14 so that the scanning state of the laser light with respect to the incident surface 15a of the wavelength conversion member 15 becomes a predetermined scanning state.

Also in the third embodiment, the same effect as in the first embodiment can be obtained. Also in the third embodiment, the configuration of the second embodiment or the configuration of each modification shown in FIGS. 11A to 12B can be applied as appropriate.

<Other changes>
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

For example, the shape of the

leaf springs

102 and 112 is not necessarily limited to the shape shown in the first embodiment and the second embodiment. For example, in FIG. The region of the frame portion 102a other than the region sandwiched between the screws 103 may be omitted.

Further, the shape of the mirror 17 does not necessarily have to be a square in a plan view, and may be a rectangle or a circle in a plan view. The shape of the support portion 102b can also be changed as appropriate.

Further, the type of the phosphor particles 203a included in the phosphor layer 203 of the wavelength conversion member 15 is not necessarily one type. For example, a plurality of types that generate fluorescence with different wavelengths by the laser light from the laser light source 12 are used. Phosphor particles 203 a may be included in the phosphor layer 203. In this case, light of a predetermined color is generated by the diffused light of the fluorescence generated from each type of phosphor particles 203a and the diffused light of the laser light that has not been wavelength-converted by the phosphor particles 203a.

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.

The light source device and the light projecting device of the present disclosure can accurately and accurately detect the state of a deflector that scans light with respect to a wavelength conversion member. For example, as a light source device for a vehicle headlamp It is very useful.

DESCRIPTION OF SYMBOLS 1 Light projector 2 Light source device 3 Projection

optical system

3b, 14a, 14b Section 12 Laser light source 14 Optical deflector 15 Wavelength conversion member 15a Incident surface 17 Mirror (light guide member)
18 Circuit board 19, 19 'Position detector 20 Mirror (light guide member)
21 Condensing lens (Condensing member)
22 Concave mirror (light guide member, condensing member)
23 Condensing lens (Condensing member)
31 Band pass filter 32 Neutral filter 301 Controller

Claims

A laser light source for emitting laser light;
A wavelength converting member that has an incident surface on the optical path of the laser light, converts the wavelength of the laser light to another wavelength, generates converted light, and diffuses the converted light;
An optical deflector for scanning the laser beam at least one dimension on the incident surface;
The laser beam specularly reflected on the incident surface is received with respect to all scanning ranges on the incident surface, and a position detector that outputs a detection signal corresponding to the light receiving position of the laser beam is provided.
A light source device characterized by that.
The light source device according to claim 1,
A band-pass filter that removes the converted light and transmits the specularly reflected laser light in the optical path of the specularly reflected laser light;
A light source device characterized by that.
The light source device according to claim 1,
A neutral density filter for reducing the specularly reflected laser light in the optical path of the specularly reflected laser light;
A light source device characterized by that.
In the light source device according to any one of claims 1 to 3,
A condensing member for condensing the laser light specularly reflected on the incident surface of the wavelength conversion member on a light receiving surface of the position detector;
A light source device characterized by that.
In the light source device according to any one of claims 1 to 4,
The position detector is installed on the circuit board at a position different from the traveling direction of the laser beam specularly reflected by the incident surface,
A light guide member for guiding the specularly reflected laser light to the position detector;
A light source device characterized by that.
The light source device according to claim 5,
The light guide member further includes a function of condensing the laser light regularly reflected on the incident surface onto a light receiving surface of the position detector,
A light source device characterized by that.
The light source device according to any one of claims 1 to 6,
A controller for controlling the optical deflector;
The controller controls the optical deflector based on a detection signal from the position detector so that a scanning state of the laser light with respect to the incident surface of the wavelength conversion member becomes a predetermined scanning state.
A light source device characterized by that.
The light source device according to claim 7.
The controller detects the disappearance period based on the detection signal of the lighting period of the laser light source when the disappearance period occurs in the detection signal from the position detector because the laser light source is in a non-lighting state. Interpolating a signal, and controlling the optical deflector based on the detection signal after the interpolation,
A light source device characterized by that.
In the light source device according to any one of claims 1 to 8,
The controller acquires a light amount signal corresponding to the light amount of the laser light specularly reflected on the incident surface of the wavelength conversion member based on a signal from the position detector, and based on the acquired light amount signal, Determining the state of the wavelength conversion member;
A light source device characterized by that.
The light source device according to any one of claims 1 to 9,
A projection optical system for projecting the light diffused by the wavelength conversion member,
A light projection device characterized by that.