JP6356454B2 - Optical scanner and vehicle headlamp device - Google Patents

Description

  The present invention relates to an optical scanner including an optical deflector manufactured as a MEMS (Micro Electro Mechanical Systems) device and a vehicle headlamp device.

  An optical scanner equipped with an optical deflector of a MEMS device and a vehicle headlamp device equipped with the same are known (eg, Patent Document 1).

  The optical deflector of the optical scanner in the vehicle headlamp device of Patent Document 1 has a reflection portion, and rotates the reflection portion around two axes orthogonal to each other, and transmits the light from the light source. The light is deflected by reflection at the reflection portion, and the irradiation area in front of the vehicle is scanned by reflected light. The vehicle headlamp device also controls the diameter of the light spot of the scanning light emitted from the optical deflector, the scanning speed of the light spot in the vehicle width direction, the scanning speed of the light spot in the vehicle longitudinal direction, and the amount of light emitted from the laser light source. Thus, various light distribution patterns can be generated for the irradiation region.

  On the other hand, Patent Document 2 discloses a vehicle headlamp device that irradiates the front of a vehicle with scanning light from an optical scanner including the optical deflector, although the optical deflector is not a MEMS device. Also in the vehicle headlamp device, the light deflector of the optical scanner is reciprocally rotated around the axis, and the rotational speed of the reflector and the output of the light source are controlled to provide various light distribution patterns. Is generated.

JP 2013-8480 A JP 2009-48786 A

  For vehicles that reflect light from a light source by a reflector that reciprocates around an axis and uses the reflected light as scanning light, and variously control the light distribution pattern through control of the illuminance etc. of the scanning light In the headlamp device, a fine light distribution pattern is required. For example, in order to obtain a light distribution pattern with resolution equivalent to VGA resolution (640 × 480 pixels) in a projector, a horizontal scanning direction requires a scanning frequency of 18 kHz or more and a deflection angle of about 50 °, and a vertical direction. Requires a scanning frequency of about 60 Hz and a deflection angle of about 30 °.

  When the optical deflector is not an optical deflector of a MEMS device but an optical deflector using a rotation mechanism of a normal machine as in the optical scanner of Patent Document 2, vertical scanning is performed with respect to the scanning frequency and the deflection angle. Although the above values can be secured, it is impossible to achieve the above values for horizontal scanning.

  In the optical deflector of the conventional MEMS device, including the optical deflector of the optical scanner of Patent Document 1, the reflection part is unique. In addition, in order to obtain a desired high-speed resonance frequency, it is difficult to increase the size of the reflecting portion from structural design simulation, and the reflecting portion is limited to a small size of about 1 mmφ. For this reason, the light source that can be used for the conventional MEMS optical deflector is limited to a laser light source having a small spot diameter.

  On the other hand, LEDs (light emitting diodes) have the advantage that they are inexpensive and have high durability compared to laser light sources, and also have the advantage that speckle noise does not occur. However, there is a problem in using it as a light source for the MEMS optical deflector due to the above-mentioned limitations.

In other words, a normal LED that can emit a necessary amount of light as a vehicular headlamp device has a large light source size of about 1 × 4 mm ^2. Therefore, when the solid angle of light emitted from the LED is 3 steradians, Etendue (= light emitting area of light source × divergent solid angle) is about 12 mm ² steradians. On the other hand, when the incident solid angle of the reflecting part with respect to incident light having a reflecting part of 1 mmφ and an incident angle of 30 ° is 3.8 steradians, the etendue of the reflecting part on the incident side (= incidence solid angle × effective area) ) Is about 3 mm ² steradians when the incident angle is 30 °. Therefore, only about 1/4 of the light emitted from the LED can be applied to the reflecting portion, and the remaining about 3/4 cannot hit the reflecting portion and cannot be used as reflected light.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical scanner and a vehicle headlamp device that can ensure the use efficiency of light even for a light source having a large divergence angle while using an optical deflector of a MEMS device. is there.

An optical scanner of the present invention is manufactured as a light source, a MEMS device, an optical deflector that deflects and emits incident light from the light source by reflection at a reflection portion, and the reflection portion is parallel to a first axis. A first actuator that reciprocally rotates around an axis, and that emits reflected light from the reflecting portion as scanning light, wherein the optical deflector surrounds and supports the reflecting portion. One frame body and a second frame body surrounding and supporting the first frame body, wherein the plurality of reflection sections are set to have the same resonance frequency, and The first frame body is arranged inside the first frame body in a line along a second axis line orthogonal to the one axis line, and is reciprocally rotatable around an axis line parallel to the first axis line. The first actuator is supported by the first frame. Serial reciprocally rotated at a resonant frequency, wherein the light source, the direction in which light from the light source, the arrangement of the plurality of reflecting portions of the optical deflector is incident to ensure no and prescribed incident amount to protrude And a plurality of light emitting diodes arranged in a line.

According to the present invention, the plurality of reflecting portions are disposed inside the first frame body in a line along the second axis, and reciprocally rotate around the axis parallel to the first axis at the same resonance frequency. doing. Thereby, even if the light from a light source has a large divergence angle, it can inject into the several reflection part long arranged along the 2nd axis. And the reflected light of a some reflection part is radiate | emitted in the same direction, and is radiate | emitted from an optical scanner as scanning light. As a result, even when a light source having a large divergence angle is used in the optical scanner, it is possible to ensure the light use efficiency in the optical deflector of the MEMS device. According to the present invention, in an optical scanner equipped with an optical deflector of a MEMS device, by using a light emitting diode as a light source, the cost and durability of the light source can be improved and speckle noise can be prevented.

  In the optical scanner according to the aspect of the invention, the reflection is performed at a non-resonance frequency lower than the resonance frequency, and is interposed between the third frame surrounding the second frame and the second frame and the third frame. And a second actuator for reciprocatingly rotating the portion around the second axis.

  According to this configuration, the reflected light from the plurality of reflecting portions also scans in a direction corresponding to the direction around the second axis. As a result, in the two-dimensional optical scanner, even when a light source having a large divergence angle is used, it is possible to ensure the light use efficiency in the optical deflector of the MEMS device.

  In the optical scanner according to the aspect of the invention, the first actuator or the second actuator is a piezoelectric actuator provided in the optical deflector, or a coil portion provided in the optical deflector, and disposed outside the optical deflector. It is preferable that the electromagnetic actuator includes a magnet that generates a predetermined magnetic field in the arrangement space of the coil unit.

  According to this configuration, the reflecting portion of the optical deflector can be smoothly reciprocated around the first and second axes using the piezoelectric actuator or the electromagnetic actuator.

  The vehicle headlamp apparatus of the present invention is equipped with the optical scanner and scans an irradiation area with scanning light from the optical scanner.

  According to the vehicle headlamp device of the present invention, the light from the light source is long along the second axis in the optical deflector even when the light from the light source has a large divergence angle, while including the optical deflector of the MEMS device. The light is incident on the plurality of reflective portions arranged side by side and is reflected in the same direction from the plurality of reflective portions. Therefore, in the optical scanner equipped in the vehicle headlamp device, even when a light source having a large light divergence angle is used, the light use efficiency can be ensured.

  In the vehicle headlamp device according to the present invention, the optical scanner includes an imaging member disposed at an imaging position where the light emitted from the optical deflector forms an image, and imaging on the imaging member. It is preferable to include a projection lens that projects onto the irradiation area.

  According to this configuration, the vehicle headlamp device can irradiate the irradiation area with the light distribution pattern generated on the imaging member.

  In the vehicle headlamp device of the present invention, the light emitting diode of the light source emits blue light or ultraviolet light, and the imaging member is a phosphor that converts a part of the blue light into yellow, or ultraviolet light. It is preferable that the phosphor is a phosphor encapsulating plate in which phosphors that convert the wavelength of all of them into blue, green, and red visible light are encapsulated.

  According to this configuration, the addition of a dedicated imaging member can be omitted by using the phosphor encapsulating plate as the imaging member. Further, the scanning light from the projection lens is white that is a mixed color of blue and yellow or visible light including three colors of blue, green, and red, that is, white that is a mixed color of three colors of blue, green, and red, The color of the illumination light of the vehicle headlamp device can be used.

The block diagram of the vehicle headlamp apparatus. The perspective view which looked at the front of an optical deflector from diagonally. (A) is a figure which shows the state of a piezoelectric actuator when the degree of curvature is the minimum, and (b), respectively, when the degree of curvature is the maximum. (A) is when no applied voltage is supplied to the piezoelectric film of any piezoelectric cantilever, (b) is when the applied voltage where the adjacent piezoelectric cantilevers have the opposite phase and the maximum absolute value is supplied. The figure which shows the state of a piezoelectric actuator. The figure which shows the arrangement | positioning relationship of each element in an optical system, and the course of light. (A)-(e) is a figure which shows the various light distribution patterns which a vehicle headlamp apparatus produces | generates. The perspective view of another optical deflector. (A) And (b) is explanatory drawing of the electromagnetic actuator of FIG. 7 when the direction of the electric current in a coil wire is each reverse direction. The perspective view of the optical deflector which deform | transformed the optical deflector of FIG. The block diagram of another vehicle headlamp.

  FIG. 1 is a configuration diagram of a vehicle headlamp device 1. The vehicle headlamp device 1 includes an optical scanner including a control unit 2 and an optical system 3.

  The camera 11 is an infrared camera or a normal color camera, and is originally installed in the vehicle to monitor an object such as a pedestrian in a vehicle collision prevention device or the like, and images the front of the vehicle. Then, a captured image is generated. The vehicle headlamp device 1 controls an orientation pattern (FIG. 6), which will be described later, based on a captured image of a camera 11 provided in a vehicle collision prevention device or the like. The processing of the control unit 2 is not performed by a control unit dedicated to the optical scanner, but is performed by a control device that controls the entire vehicle including the collision prevention device in parallel processing and processing such as collision prevention. Also good.

  The control unit 2 includes at least a controller 10, a memory 12, a light source control unit 13, and an optical deflector control unit 14. The controller 10 calculates a light distribution pattern based on a captured image signal in front of the vehicle from the camera 11, and outputs a control signal for irradiating scanning light to the illumination area in front of the vehicle with the calculated light distribution pattern. Output to the deflector controller 14. The memory 12 includes a ROM that stores data of a program executed by the controller 10 and a predetermined nonvolatile storage device together with a RAM that is used in order for the controller 10 to temporarily store predetermined data when the controller 10 performs an operation. The light source control unit 13 controls on / off switching of the light source 21 of the optical system 3 and the amount of drive power supplied to the light source 21. The optical deflector control unit 14 supplies driving power to the optical deflector 23 of the optical system 3.

  The optical system 3 includes a light source 21, a converging lens 22, an optical deflector 23, a convex lens 24, a transmissive phosphor plate 25, and a projection lens 26. The light source 21, the converging lens 22, the light deflector 23, the convex lens 24, and the phosphor plate 25 are housed in a casing 27, and the projection lens 26 is attached to the front opening of the casing 27.

  The light source 21 includes a plurality of (for example, four) LEDs (light emitting diodes) 29 of about 1 mm square arranged in a row and mounted in one package. The package is equipped with a lens for narrowing the radiation angle of the entire LED light to about 5 ° to provide directivity. From the light source 21, horizontally long light (light beam) of 1 mm × 4 mm is emitted through the lens.

  The LED 29 is controlled to be turned on and off by the light source control unit 13 and the amount of light is controlled in accordance with the supply current from the light source control unit 13. The LED 29 emits blue (emission wavelength: 460 nm) or ultraviolet light (e.g., emission wavelength: 380 nm), and the emitted light travels toward the optical deflector 23.

  The converging lens 22 is disposed between the light source 21 and the optical deflector 23. The light from the light source 21 spreads at a radiation angle, but is collected by the converging lens 22 and is incident on the array of the reflecting portions 36 (FIG. 2) of the light deflector 23 with the original light source dimensions. The converging lens 22 is used alone as a convex lens in the illustrated example, but may be used in combination with a collimator lens.

  The light deflector 23 deflects the light incident from the light source 21 by the reflection of the reflecting portion 36 (FIG. 2) and emits the light toward the phosphor plate 25. The detailed structure of the optical deflector 23 will be described later with reference to FIG. Light emitted from the optical deflector 23 reaches the phosphor plate 25 through the convex lens 24 and is imaged on the phosphor plate 25.

  The light source control unit 13 can control the luminance of image formation on the phosphor plate 25 by controlling the light quantity of the LED 29. Thus, the image formation on the phosphor plate 25 becomes a single color of the light emission color (blue or ultraviolet light) of the LED 29 with the brightness adjusted. In the light distribution pattern of FIG. 6 described later, an image formed on the phosphor plate 25 is generated in an irradiation area in front of the vehicle.

  The convex lens 24 is disposed between the light deflector 23 and the phosphor plate 25 so that an image is appropriately formed on the phosphor plate 25 disposed at the imaging position. The convex lens 24 can be omitted.

  The phosphor plate 25 has a flat plate structure in which a predetermined phosphor is enclosed in a transparent glass as a phosphor encapsulating plate, and transmits light from the light deflector 23 toward the projection lens 26.

  The phosphor of the phosphor plate 25 converts incident light into light having a long wavelength and emits it. By changing the type of the phosphor, the wavelength of the incident light and the wavelength of the emitted light can be appropriately selected. For example, a phosphor that converts part of incident light of blue light into yellow light is selected, and blue light that has not been wavelength-converted and yellow light that has been wavelength-converted are mixed to emit white light. it can. Further, a plurality of kinds of phosphors that convert ultraviolet light into three colors of blue, green, and red can be selected, and white light can be emitted by mixing the three colors.

  In addition, as a fluorescent substance which changes blue light into yellow light, there exist some which sintered yellow fluorescent substances, such as YAG (yttrium, aluminum, garnet), for example. The wavelength conversion efficiency of YAG is as high as about 95%.

  FIG. 2 is a perspective view of the front surface of the optical deflector 23 as viewed obliquely. In the optical deflector 23, the side on which light from the light source 21 is incident and reflected is defined as the front side of the optical deflector 23, and the opposite side is defined as the back side of the optical deflector 23. The front and back surfaces of the optical deflector 23 refer to the front and back surfaces of the optical deflector 23, respectively.

  For convenience of description of the structure, a three-axis orthogonal coordinate system of the origin o, x-axis, y-axis, and z-axis is defined in FIG. The x-axis and the y-axis are parallel to the long and short sides of the rectangular outer frame 33, and the z-axis has a positive direction from the back surface to the front surface of the optical deflector 23. In FIG. 2, the three-axis orthogonal coordinate system is illustrated outside the optical deflector 23 for the sake of space, but it is assumed that the origin o of the three-axis orthogonal coordinate system is at the center of the outer frame 33. The structure 23 will be described.

  The optical deflector 23 is manufactured in a symmetric structure with respect to the yz plane by MEMS technology. The optical deflector 23 includes an inner frame 31 (an example of “first frame”), an intermediate frame 32 (an example of “second frame”), and an outer frame 33 (“third frame” in order from the inside to the outside. 1 example) of “body”. The inner frame 31, the middle frame 32, and the outer frame 33 are arranged with their centers aligned with the origin o. The middle frame 32 surrounds the inner frame 31, and the outer frame 33 surrounds the middle frame 32.

  A plurality of (for example, four) reflecting portions 36 are arranged in a line in the x-axis direction in the inner frame 31. Each reflecting portion 36 is coupled to the inner periphery of the inner frame 31 by a torsion bar 37 protruding from both sides in the y-axis direction. The reflection part 36 is formed in a square of 1.5 mm square, for example, when viewed from the front. The value of 1.5 mm is within a dimension that can ensure that the reflecting portion 36 resonates at a desired high-speed resonance frequency Fr (eg, 18 kHz or higher).

  A gap of, for example, 50 μm is formed between the reflecting portions 36 adjacent in the arrangement direction in order to prevent mutual collision. Unlike laser light, LED light has a large divergence angle, so it is considered that the influence of a 50 μm gap on the pattern of irradiated light is very small. Considering the entire four adjacent reflecting portions 36 as a single reflecting portion 36, the four reflecting portions 36 secure a region of the reflecting portion sufficient to reflect the incident LED light and perform a raster scan. Is done.

  Each reflecting portion 36 is reciprocally rotatable around the axis of the torsion bar 37 coupled to each reflecting portion 36 at the same resonance frequency Fr. In general, the resonance frequency of the reflecting portion 36 is determined only by the shape and size of the reflecting portion 36 and the shape and size of the torsion bar 37 that supports the reflecting portion 36 on the inner frame 31. Even if a plurality of reflecting portions 36 are arranged, all the reflecting portions 36 reciprocately rotate around the axis of the torsion bar 37 at the basic resonance frequency.

  The inner piezoelectric actuator 39 (an example of “first actuator”) is disposed on both sides of the inner frame 31 in the x-axis direction, and is coupled to the inner frame 31 and the middle frame 32 at the distal end side and proximal end sides, respectively. doing. Regarding the size and arrangement of the inner piezoelectric actuator 39, the horizontal scanning angle of the reflecting portion 36 (scanning light as reflected light from the reflecting portion 36 was swung to the maximum on the positive side in the x-axis direction with respect to the yz plane. The difference between the deflection angle of the hour and the deflection angle when maximally swinging to the negative side is optimized.

  The piezoelectric films of the inner piezoelectric actuators 39 on both sides in the x-axis direction are supplied with driving voltages having a resonance frequency Fr in opposite phases. As a result, the distal end portions of the inner piezoelectric actuators 39 on both sides are displaced to the opposite sides with respect to the front surface of the middle frame 32 to which the proximal end portions are coupled, and with respect to the short side of the middle frame 32. The inner frame 31 is reciprocally rotated around a short-side direction center line (one example of “first axis”) as a parallel center line. Accordingly, each reflecting portion 36 also reciprocally rotates at the resonance frequency Fr around the axis of the torsion bar 37 coupled to the reflecting portion 36 (an example of “an axis parallel to the first axis”).

  Supplementally, the short-side direction center line of the middle frame 32 is relative to the xz plane as the middle frame 32 reciprocates around the long-side direction center line of the middle frame 32 by the action described later by the outer piezoelectric actuator 40. Increase or decrease the deflection angle as the inclination angle. Therefore, the short-side direction center line of the middle frame 32 is parallel to the y-axis only when the inclination angle with respect to the xz plane becomes 0 °.

  Since the reflecting portion 36 has a predetermined inertia, when the inner frame 31 starts reciprocating rotation around the center line in the short side direction of the middle frame 32, the rotation of the inner frame 31 is common to each reflecting portion 36. An inertial force in the direction of rotation opposite to the direction is generated for a predetermined period. As a result, the reflecting portion 36 starts reciprocating rotation at the same time in the same phase and at the resonance frequency Fr without being in reverse phase. Alternatively, the back surface structure of the reflective portion 36 is slightly asymmetrical (for example, a little heavier on one side) with the short-side direction center line (first axis) in between, so that inertial force is actively used to rotate in phase. Can be moved.

  The outer piezoelectric actuator 40 (an example of “second actuator”) is interposed between the middle frame 32 and the outer frame 33. Specifically, it has a plurality of piezoelectric cantilevers 41 coupled in series in a meander pattern arrangement, the base end is coupled to the short side of the outer frame 33, and the tip is coupled to the short side of the middle frame 32. . The outer piezoelectric actuator 40 reciprocally rotates the inner frame 32 around the x axis at a non-resonant frequency Fs (eg, about 60 Hz).

  FIG. 3 is an explanatory diagram of the operating principle of the piezoelectric actuator 43 manufactured by MEMS. The description of the operating principle for the piezoelectric actuator 43 applies to both the inner piezoelectric actuator 39 and the outer piezoelectric actuator 40. 3A shows a state of the piezoelectric actuator 43 when the degree of curvature of the piezoelectric actuator 43 is minimum, and FIG. 3B shows a state of the piezoelectric actuator 43 when the degree of curvature of the piezoelectric actuator 43 is maximum.

The piezoelectric actuator 43 has a laminated structure of an Si layer 44, an intermediate oxide film layer 45, an Si layer 46, a surface oxide film layer 47, and a PZT (zinc zirconate titanate) layer 48 in order from the bottom. Although not shown, electrode layers are formed above and below the PZT layer 48. Both the intermediate oxide film layer 45 and the surface oxide film layer 47 are made of silicon oxide (SiO ₂ ).

  The Si layer 44, the intermediate oxide film layer 45, and the Si layer 46 constitute a layer of an SOI (Silicon on Insulator) wafer. The SOI wafer is formed by combining a silicon wafer of the Si layer 44 and a silicon wafer of the Si layer 46 with a silicon oxide film. As shown in FIG. The surface oxide film layer 47 is generated by thermally oxidizing the Si layer 46 of the SOI wafer.

  The PZT layer 48 is formed on an SOI wafer by a thin film forming process such as sputtering, ion plating, and sol-gel. Specifically, a PZT layer 48 is formed on the surface oxide film layer 47 of the SOI wafer. Next, the Si layer 44 and the intermediate oxide film layer 45 are removed by etching, leaving one end side of the PZT layer 48 from the back side of the SOI wafer. Thus, one end side of the Si layer 46, the surface oxide film layer 47, and the PZT layer 48 that has not been etched becomes the base end of the piezoelectric actuator 43, and the opposite side of the base end is the free end (working end or front end) of the piezoelectric actuator 43. Become.

  The power source 49 applies direct current or alternating current that increases or decreases at the resonance frequency Fr or the non-resonance frequency Fs to both surfaces of the PZT layer 48. When the applied voltage of the PZT layer 48 is 0 V, the piezoelectric actuator 43 is straightened from the base end to the tip end in a side view. When the absolute value of the applied voltage of the PZT layer 48 is maximized, the piezoelectric actuator 43 is bent to the maximum in a side view. Thus, the piezoelectric actuator 43 moves the tip up and down in the A3 direction with respect to the base end at the resonance frequency Fr or the non-resonance frequency Fs.

  The laminated structure of the Si layer 44 to the surface oxide film layer 47 in FIG. 3 matches the laminated structure of the outer frame 33 in FIG. The inner piezoelectric actuator 39 and the piezoelectric cantilever 41 in FIG. 2 match the laminated structure of the Si layer 46, the surface oxide film layer 47, and the PZT layer 48 (piezoelectric film) of the piezoelectric actuator 43.

  That is, the base ends of the inner piezoelectric actuator 39 and the piezoelectric cantilever 41 are connected to the inner frame 32 and the adjacent piezoelectric cantilever 41 in the meander pattern arrangement, and these connection destinations include the Si layer 44 and the intermediate oxide film layer 45. However, only the Si layer 46 and the surface oxide film layer 47 are provided. Similarly, the inner piezoelectric actuator 39 and the tip of the piezoelectric cantilever 41 are connected to the inner frame 31 and the adjacent piezoelectric cantilever 41 in the meander pattern arrangement, and these connection destinations include the Si layer 44 and the intermediate oxide film layer 45. However, only the Si layer 46 and the surface oxide film layer 47 are provided.

  FIG. 4 is an explanatory view of the action of the outer piezoelectric actuator 40. In FIG. 4, the piezoelectric cantilevers 41 are identified by attaching the symbols of the piezoelectric cantilevers 41 a to 41 d in order from the side closer to the middle frame 32. When the piezoelectric cantilevers 41a to 41d are generically referred to, they are simply referred to as “piezoelectric cantilevers 41”. (A) shows that when the applied voltage is not supplied to the piezoelectric film of any piezoelectric cantilever 41 by the outer piezoelectric actuator 40, (b) shows that the adjacent piezoelectric cantilevers 41 are in reverse phase and have the maximum absolute value. The state of the piezoelectric actuator 43 when the applied voltage is supplied is shown.

  When the piezoelectric cantilever 41 is counted from the side of the middle frame 32, the piezoelectric films of the odd-numbered piezoelectric cantilevers 41a and 41c and the piezoelectric films of the even-numbered piezoelectric cantilevers 41b and 41d apply a reverse-phase driving voltage at the non-resonant frequency Fs. Is done. As a result, as shown in FIG. 4B, the piezoelectric cantilevers 41a and 41c and the piezoelectric cantilevers 41b and 41d are curved with the convex side in the opposite direction, and the displacement amount of the distal end relative to the proximal end of the outer piezoelectric actuator 40 is It becomes equal to the total amount of displacement of the tip with respect to the base end of each piezoelectric cantilever 41.

  As a result, the outer piezoelectric actuators 40 on both sides reciprocally rotate at the non-resonant frequency Fs around the x axis at the coupling end with the middle frame 32. Accordingly, the middle frame 32 reciprocates around the x axis at a non-resonant frequency Fs, and the inner frame 31 rotates around the long-side direction center line of the inner frame 31 (an example of “second axis”). The reflector 36 reciprocally rotates around the center line in the long side direction of the inner frame 31 at the nonresonant frequency Fs.

  Supplementally, during the operation of the outer piezoelectric actuator 40, the long-side direction center line of the inner frame 31 reciprocally rotates around the y axis at the resonance frequency Fr in the xz plane. The long-side direction center line of the inner frame 31 (an example of “second axis”) coincides with the x axis when the normal of the reflecting portion 36 coincides with the z axis.

  FIG. 5 shows the positional relationship between the light source 21, the light deflector 23, and the phosphor plate 25, and the light path. The light deflector 23 is arranged so that the x-axis and the y-axis are associated with the horizontal direction and the vertical direction of the irradiation area of the vehicle headlamp device 1, respectively.

  As described above, the LED light raster-scanned by the light deflector 23 is imaged on the emission surface of the phosphor plate 25 with a specific light distribution pattern. Then, the imaged light on the emission surface of the phosphor plate 25 passes through the projection lens 26 (FIG. 1) not shown in FIG. 5, and then the horizontal scanning angle range A5a and the vertical scanning angle range. The light is emitted in front of the vehicle with a range width of A5b, the corresponding irradiation area is raster scanned, and an image is projected onto the irradiation area.

  The type of phosphor that is sealed in the phosphor plate 25 is selected according to the color of the LED light of the LED 29 so that the emitted light from the phosphor plate 25 is legally white. For example, when the LED light of the LED 29 is blue, a part of the blue LED light that has reached the incident surface side of the phosphor plate 25 is converted into long wavelength yellow light by the phosphor of the phosphor plate 25. The remainder passes through the phosphor plate 25 without being wavelength-converted. As a result, white light as mixed color light of blue light and yellow light is emitted from the emission surface of the phosphor plate 25 while maintaining the light distribution pattern.

  FIGS. 6A to 6E show various light distribution patterns generated by the vehicle headlamp device 1. Reference numeral 53 denotes a vertical plane orientation pattern generated on a light distribution evaluation screen disposed in front of the vehicle and facing the vehicle at a predetermined distance. Reference numeral 54 denotes a road orientation pattern generated on the road surface by the vehicle headlamp device 1. Reference numeral 55 denotes a front end line of a vehicle on which the vehicle headlamp device 1 is mounted. Reference numeral 56 denotes a center line of the vehicle width of the vehicle on which the vehicle headlamp device 1 is mounted.

  6 (a) to 6 (e), when the vehicle headlamp device 1 emits scanning light to the front irradiation region, a left vertical plane alignment pattern 53 is generated on the light distribution evaluation screen. A road alignment pattern 54 on the right side is generated on the road. The orientation pattern in FIG. 6 is an orientation pattern on the assumption that the vehicle passes on the left side with respect to the center line of the road and the opposite lane is on the right side of the center line.

  The alignment pattern of FIG. 6A is an alignment pattern by a traveling beam (high beam), and the light source 21 is continuously turned on during the raster scan by the light deflector 23, and the light distribution pattern becomes the brightest.

  The alignment pattern in FIG. 6B is a standard alignment pattern in an urban area using a low beam. In the upper half period of the raster scan, the cut-off pattern is formed by turning off the light source 21.

  In existing vehicle headlamps, two light source bulbs for high beam and low beam are used, or high / low switching is performed using a mechanical light shielding plate. 1, it is possible to easily switch between high and low simply by controlling the lighting timing of one light source 21.

  FIGS. 6C to 6E show various alignment patterns of ADB (light distribution variable headlamp) that cuts the scanning light by only a part of the traveling beam in conjunction with the front detection system using the camera 11. .

  The orientation pattern in FIG. 6C is a light distribution pattern aimed at anti-glare for the driver of the oncoming vehicle 58. The alignment pattern in FIG. 6D is an alignment pattern aimed at anti-glare for the driver of the preceding vehicle 59. (E) is a light distribution pattern aiming at anti-glare of the pedestrian 60 ahead. As described above, the raster scan type variable light distribution vehicle headlamp system that combines the light source 21, the light deflector 23, and the phosphor plate 25 has a very simple and inexpensive configuration and can be arranged for various ADB scenes. It is possible to provide a light pattern.

  FIG. 7 is a perspective view of another optical deflector 63. In the optical deflector 63, the same elements as those of the optical deflector 23 (FIG. 2) are given the reference numerals attached to the elements of the optical deflector 23. In the optical deflector 63, the outer piezoelectric actuator 40 of the optical deflector 23 is replaced with an electromagnetic actuator 64 including a magnet 68 and a coil wire 69 (an example of a “coil part”).

  The inner piezoelectric actuator 39 is manufactured as an element of the optical deflector of the MEMS device. On the other hand, the electromagnetic actuator 64 includes a magnet 68 and a coil wire 69. The coil wire 69 is manufactured as an element of the optical deflector 63 of the MEMS device, and the magnet 68 is manufactured separately from the optical deflector 63. Arranged outside the optical deflector 63.

  Also in FIG. 7, for convenience of explanation, a three-axis orthogonal coordinate system is defined. The origin o of the three-axis orthogonal coordinate system is set at the center of the outer frame 33 as a stationary part, and the x axis and the y axis are defined in directions parallel to the long side and the short side of the outer frame 33.

  The torsion bars 66 are disposed on both sides of the middle frame 32 in the x-axis direction, extend along the x-axis, and are coupled to the middle frame 32 and the outer frame 33 at both ends. The electrode pad 67 is provided on the surface of one short side portion of the outer frame 33. The coil wire 69 is formed so as to go around the surface of the inner frame 32 a plurality of times and to be connected to the electrode pad 67 at both ends via one torsion bar 66.

  The two magnets 68 are disposed on both sides of the optical deflector 63 in the y-axis direction so that the N-pole side and the S-pole side face each other in the y-axis direction. As a result, a magnetic field whose direction is parallel to the y-axis is formed in the arrangement space of the coil wire 69 in the middle frame 32.

  FIG. 8 is an explanatory diagram of the electromagnetic actuator 64 of FIG. In (a) and (b), the direction of the current in the coil wire 69 is different. The two magnets 68 are arranged with the middle frame 32 interposed therebetween so that the N pole and the S pole face each other, and a magnetic field B directed from the N pole to the S pole is generated in the arrangement space of the middle frame 32. As a result, when a current flows through the coil wire 69, Lorentz forces in opposite directions are generated in the two extending portions of the coil wire 69 perpendicular to the direction of the magnetic field B. Rotate around the direction center line.

  Since the coil wire 69 is supplied with alternating current having a non-resonant frequency Fs through the electrode pad 67, the direction of the current in the coil wire 69 is alternately reversed at the non-resonant frequency Fs. As a result, the arrangement of the reflecting portions 36 reciprocally rotates around the long-side direction center line of the middle frame 32 at the non-resonant frequency Fs, so that the scanning light as the reflected light of the reflecting portion 36 has the non-resonant frequency Fs. The light is emitted at a vertical scanning frequency.

  FIG. 9 is a perspective view of an optical deflector 75 obtained by modifying the optical deflector 63 (FIG. 7) of FIG. In the optical deflector 75, the same elements as those of the optical deflector 63 are denoted by the reference numerals attached to the elements of the optical deflector 63. In the optical deflector 75, the inner piezoelectric actuator 39 of the optical deflector 63 is replaced with an electromagnetic actuator 79 including a coil wire 78 and a magnet 80. The coil wire 78 is manufactured as an element of the optical deflector 75 as a MEMS device, while the magnet 80 is disposed outside the optical deflector 75.

  The torsion bars 76 are disposed on both sides of the inner frame 31 in the y-axis direction, and are coupled to the inner frame 31 and the middle frame 32 at both ends. The two electrode pads 77 are formed on the surface of one long side portion of the middle frame 32. The coil wire 78 is formed on the surface of the inner frame 31 so as to circulate the inner frame 31 a plurality of times, and is connected to electrode pads 77 at both ends via one torsion bar 76. The electrode pad 77 is connected to an electrode pad (not shown) of the outer frame 33 through an internal wiring formed under the coil wire 69 in the optical deflector 63.

  The two magnets 80 are disposed in the x-axis direction with the optical deflector 75 interposed therebetween, and the N pole and the S pole are opposed to each other. As a result, a magnetic field from the N pole to the S pole in a direction parallel to the x axis is generated in the arrangement space of the inner frame 31. As a result, when a current flows through the coil wire 78, Lorentz forces in opposite directions are generated in the two extending portions of the coil wire 78 extending in a direction perpendicular to the direction of the magnetic field. The middle frame 32 is rotated around the center line in the short side direction.

  Since the alternating current having the resonance frequency Fr is supplied to the coil wire 78 through the electrode pad 77, the direction of the current in the coil wire 78 is reversed at the resonance frequency Fr. As a result, the arrangement of the reflectors 36 reciprocates around the short-side direction center line (the axis of the torsion bar 76) of the middle frame 32, and the reflected light from the reflectors 36 is used as the horizontal scanning light to the resonance frequency Fr. Exit with

  FIG. 10 is a configuration diagram of the vehicle headlamp device 91. In the vehicle headlamp device 91, the same elements as those of the vehicle headlamp device 1 (FIG. 1) are denoted by the reference numerals attached to the elements of the vehicle headlamp device 1. In the vehicle headlamp device 91, the optical system 3 of the vehicle headlamp device 1 is replaced with an optical system 93, and the phosphor plate 25 of the optical system 3 is replaced with an imaging device 96.

  The imaging device 96 includes a reflective phosphor plate 97 and a heat sink 98 bonded to the back surface of the phosphor plate 97. The reflective phosphor plate 97 is formed with a highly reflective film such as aluminum or silver on the back surface. The optical deflector 23 emits reflected light toward the phosphor plate 97, and the reflected light is imaged on the phosphor plate 97. The phosphor plate 97 converts the wavelength of incident light from the optical deflector 23 and reflects it toward the projection lens 26.

  The phosphor generates heat when converting blue light or ultraviolet light into long-wavelength visible light, and this heat reduces the life of the phosphor. In the vehicle headlamp device 91, the heat dissipation of the phosphor plate 97 is improved by the heat sink 98, so that the lifetime of the phosphor in the phosphor plate 97 can be prevented from being reduced.

  Compared with the light emitted from the vehicle headlamp provided with an optical system in which the phosphor is directly sealed in the light source 21 to form a white light source, the amount of light emitted from the vehicle headlight device 91 is the convergence lens 22. However, the amount of light that can be realized as a vehicle headlamp was obtained.

  The results of the performance test on the optical deflector manufactured as an example will be described as follows.

(First embodiment)
In the optical deflector 23, a voltage of 10 V was applied to the inner piezoelectric actuator 39, and a voltage of 40 V was applied to the piezoelectric cantilever 41 of the outer piezoelectric actuator 40. As a result, it was possible to obtain an optical scanning angle of 48 ° as the horizontal scanning angle (scanning angle around the y-axis) and 28 ° as the vertical scanning angle (scanning angle around the x-axis). The outer piezoelectric actuator 40 was driven in a non-resonant mode.

(Second embodiment)
A vehicle headlamp device using a biaxial optical deflector 63 (FIG. 7) by a combination of resonance driving by the inner piezoelectric actuator 39 and non-resonance driving by the electromagnetic actuator 64 shown in FIG. 7 was manufactured. The non-resonant drive electromagnetic actuator 64 has good rectilinear movement and the number of effective scanning lines is slightly increased as compared with the case of driving by the outer piezoelectric actuator 40 (Example 1). Thereby, the resolution of the light distribution pattern was improved. Further, the position of the vehicle in the vertical direction is offset using the stationary position holding characteristic of the electromagnetic actuator 64, and the aiming adjustment becomes easy.

(Third embodiment)
A vehicle headlamp apparatus using a two-axis optical deflector 75 of the type driven by electromagnetic actuators 64 and 79 on both axes shown in FIG. Since the driving force of the reflection portion 36 has increased, it has become possible to design the resonance portion to be 18 kHz by increasing the thickness of the reflection portion 36. As a result, the dynamic surface distortion of the reflecting portion 36 is reduced, and the resolution of the light distribution pattern is improved. Using this, it became easy to display arrows and numbers on the road surface as well as simple light and dark patterns. Of course, it is needless to say that aiming and road surface information display can be supported by a combination of other actuators.

  The vehicle headlamp devices 1 and 91 are particularly effective in application to an ADB vehicle headlamp device.

  Although the embodiment of the present invention has been described, the optical scanner of the present invention is not limited to the application of a vehicular lamp. The present invention can be applied to any optical scanner that uses a light source having a large divergence angle.

  In the embodiment, the two-axis driving optical scanner (two-dimensional scanner) has been described. However, the present invention can also be applied to a one-axis driving optical scanner (one-dimensional scanner). In that case, the outer piezoelectric actuator 40 that causes the outer frame 33 and the reflecting portion 36 to oscillate in a non-resonant manner is omitted. Scanning in the scanning direction in which the reflecting portion 36 is reciprocally rotated around the second axis cannot be performed. However, by overlapping with light from another light source having a light distribution as shown in FIG. As in (e) to (e), it is possible to irradiate only a part of the region with no light.

  In the embodiment, the LED 29 is used as the light source 21, but a wide light source other than the LED may be used, or a laser light source may be used.

  In the embodiment, the number of LEDs 29 of the light source 21 is equal to the number of reflecting portions 36 of the optical deflector 23, but the present invention may not be equal. The number of both is appropriately selected so that the light from the LED 29 of the light source 21 enters the array of the reflecting portions 36 of the light deflector 23 without protruding and with a desired amount of incident light.

  In the embodiment, the phosphor plate 25 also serves as an imaging member. However, the imaging member may be provided separately from the phosphor plate 25.

DESCRIPTION OF SYMBOLS 1,91 ... Vehicle headlamp device, 21 ... Light source, 22 ... Converging lens, 23, 63, 75, 85 ... Optical deflector, 25, 97 ... Phosphor plate ( (Imaging member or phosphor enclosing plate), 26... Projection lens, 29... LED, 31... Inner frame (first frame), 32. ... outer frame (third frame), 36 ... reflecting part, 39 ... inner piezoelectric actuator (first actuator), 40 ... outer piezoelectric actuator (second actuator), 64 ... electromagnetic Actuator (second actuator), 76 ... Electromagnetic actuator (first actuator), 68, 80 ... Magnet, 69, 78 ... Coil wire, 98 ... Heat sink.

Claims (6)

A light source;
An optical deflector that is manufactured as a MEMS device and deflects and emits incident light from the light source by reflection at a reflection unit;
A first actuator that reciprocally rotates the reflecting portion around an axis parallel to the first axis;
An optical scanner that emits reflected light from the reflecting section as scanning light,
The optical deflector is
A first frame that surrounds and supports the reflective portion;
A second frame that surrounds and supports the first frame,
The reflection part is a plurality,
The plurality of reflecting portions are set to have the same resonance frequency, and are arranged in a line along the second axis perpendicular to the first axis inside the first frame body. It is supported by the first frame body so as to be reciprocally rotatable around an axis parallel to the axis,
The first actuator reciprocates the first frame at the resonance frequency,
The light source has a plurality of light emitting elements arranged in a line in a direction in which light from the light source does not protrude from the array of the plurality of reflecting portions of the optical deflector and ensures a predetermined incident amount. An optical scanner comprising a diode. The optical scanner according to claim 1.
A third frame surrounding the second frame;
A second actuator interposed between the second frame and the third frame and configured to reciprocately rotate the reflecting portion around the second axis at a non-resonant frequency lower than the resonance frequency. A featured optical scanner. The optical scanner according to claim 2.
The first actuator or the second actuator is a piezoelectric actuator provided in the optical deflector, or a coil part provided in the optical deflector, and an arrangement of the coil part provided outside the optical deflector. An optical scanner comprising: an electromagnetic actuator including a magnet that generates a predetermined magnetic field in space. A vehicle headlamp device comprising the optical scanner according to any one of claims 1 to 3 and scanning an irradiation region with scanning light from the optical scanner. The vehicle headlamp device according to claim 4 ,
The optical scanner is
An imaging member disposed at an imaging position where the emitted light from the optical deflector is imaged;
A vehicular headlamp device comprising: a projection lens that projects an image formed on the imaging member onto an irradiation region. In the vehicle headlamp device according to claim 5 ,
The light emitting diode of the light source emits blue light or ultraviolet light,
The imaging member is a phosphor encapsulating a phosphor that converts a part of blue light into yellow, or a phosphor that converts all ultraviolet light into three colors of visible light of blue, green, and red. A vehicle headlamp device characterized by being a plate.