WO2022244571A1 - 光走査装置 - Google Patents
光走査装置 Download PDFInfo
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- WO2022244571A1 WO2022244571A1 PCT/JP2022/018037 JP2022018037W WO2022244571A1 WO 2022244571 A1 WO2022244571 A1 WO 2022244571A1 JP 2022018037 W JP2022018037 W JP 2022018037W WO 2022244571 A1 WO2022244571 A1 WO 2022244571A1
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- mirror
- optical
- shielding plate
- optical path
- scanning device
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/005—Diaphragms
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
- G02B2027/0118—Head-up displays characterised by optical features comprising devices for improving the contrast of the display / brillance control visibility
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B2027/0178—Eyeglass type
Definitions
- the present invention relates to an optical scanning device having a MEMS optical deflector.
- Patent Document 1 discloses an optical scanning device including a MEMS optical deflector.
- the optical scanning device is attached to one side temple of a spectacles-type head mount, and directs light from a MEMS optical deflector toward lenses and half mirrors arranged toward the front (front frame) of the spectacles. Scanning light is emitted, and an image is projected on the user's retina by the scanning light reflected by the half mirror.
- a lens and a half mirror are mounted on the temple in addition to the optical scanning device, and the optical scanning device faces the half mirror with the lens interposed therebetween.
- the emitted laser light scans the half mirror along the mirror surface, is reflected by the mirror surface, and projects an image on the retina of the user's eye.
- Patent Document 1 does not disclose the specific positional relationship between the light source, the MEMS optical deflector, and the substrate mounted in the optical scanning device.
- An object of the present invention is to provide an optical scanning device with improved quality of a light beam emitted as scanning light.
- the optical scanning device of the present invention is a substrate; a light source mounted on the substrate and emitting a light beam; a MEMS optical deflector mounted on the substrate, the MEMS optical deflector having a mirror portion whose upper surface side is a mirror surface and an actuator for reciprocally rotating the mirror portion around an axis; at least one optical path generation mirror for generating an optical path for the light beam emitted from the light source to enter the mirror section of the MEMS optical deflector; a condensing lens disposed between an optical path generation mirror on which light emitted from the light source first enters in the optical path; In the optical path, one of the optical path generating mirrors is used as a corresponding optical path generating mirror, and is located upstream of the corresponding optical path generating mirror and in the same direction as the tilting direction of the corresponding optical path generating mirror with respect to the optical axis of the optical path. a first shield plate having a first elliptical aperture disposed thereon; Prepare.
- the shielding plate arranged with the corresponding optical path generating mirror in the optical path has an aperture.
- the light beam can be improved into a light beam with high contrast as a result of cutting the low-brightness area of the periphery of the light beam by the aperture.
- FIG. 1 is a plan view of an optical scanning device; FIG. It is 1B arrow directional view of FIG. 1A.
- FIG. 1C is a view in the direction of arrow 1C of FIG. 1A;
- FIG. 1D is a view in the direction of arrow 1D of FIG. 1A;
- It is a side view of a support frame.
- FIG. 15 is a diagram showing a spectacles-type image display device 155 as an application example of the optical scanning device; 3 is a detailed diagram of the positional relationship of optical elements of an optical scanning device in which optical paths of light beams are arranged;
- FIG. 4B is an arrow view of FIG. 4A.
- FIG. 4C arrow directional view of FIG. 4A.
- FIG. 4D is a 4D arrow view of FIG.
- 1 is a configuration diagram of a main part of an optical scanning device having a concave mirror instead of a plate-like mirror
- FIG. 4 is a diagram showing the shape of a light spot when the projection screen is tilted with respect to the optical axis
- FIG. 2 is a schematic diagram of a main part of an optical scanning device equipped with RGB VCSELs;
- FIG. 1A is a plan view of the optical scanning device 10
- FIG. 1B is a view on arrow 1B of FIG. 1A
- FIG. 1C is a view on arrow 1C of FIG. 1A
- FIG. 1D is a view on arrow 1D of FIG. 1A.
- 1A to 1D show the optical scanning device 10 with the cover 33 (one-dot chain line in FIG. 1B) removed.
- the optical scanning device 10 has a support frame 12 .
- the support frame 12 has an L-shaped cross-sectional contour, and has a bottom plate portion 13a and an upright plate portion 13b that are vertically connected.
- the substrate 15 has a rectangular shape and is placed and fixed on the upper surface of the bottom plate portion 13a.
- a three-axis orthogonal coordinate system is defined.
- the X-axis and Y-axis are defined as axes parallel to the longitudinal direction (parallel to the long sides) and the lateral direction (parallel to the short sides) of the substrate 15, respectively.
- the Z-axis is defined as an axis parallel to the upright direction of the upright plate portion 13 b from the substrate 15 .
- Lp indicates a light beam.
- the course of the light beam Lp means the optical path of the light beam Lp.
- Cl is the optical axis as the central axis of the optical path of the light beam Lp.
- the optical path from VCSEL 17 to MEMS optical deflector 20 is static. Since the light beam Lp is emitted from the MEMS optical deflector 20 as scanning light, the optical path on the downstream side from the MEMS optical deflector 20 becomes dynamic.
- the light beam Lp is emitted from the left side of FIG. 1B, that is, from the negative end of the optical scanning device 10 in the X-axis direction.
- the positive side and the negative side in the Z-axis direction of the substrate 15 are the upper surface and the lower surface, respectively, the positive side and the negative side in the Z-axis direction are appropriately defined as the upper side and the lower side of the optical scanning device 10 .
- the VCSEL 17 and the MEMS optical deflector 20 are mounted on the upper surface of the substrate 15 with the X-axis direction as the alignment direction.
- the VCSEL 17 has an emitting portion 18 on its upper surface, and emits a laser beam from the emitting portion 18 upward in parallel with the Z-axis direction, that is, directly upward.
- the MEMS optical deflector 20 directs the mirror surface of the rotating mirror 21 upward.
- the MEMS optical deflector 20 is a two-dimensional scanning MEMS optical deflector in this embodiment, it may be a one-dimensional scanning MEMS optical deflector.
- Various configurations of the MEMS optical deflector itself are known. Deflectors) is selected.
- the condensing lens 19 (FIG. 1B) is arranged in the vicinity of the exit portion 18 and directly above the exit portion 18 .
- the VCSEL 17 is illustrated as a single unit, but in an actual product, it is enclosed in a package (not shown).
- the package that encloses the VCSEL 17 is made of a transparent material such as quartz glass at a portion through which the light beam from the emitting portion 18 is emitted (eg, Japanese Patent No. 4512330 and Japanese Patent Application Laid-Open No. 2009-027088).
- the condenser lens 19 is fixed (for example, glued) to the inner or outer surface of such a transparent material, or the transparent part itself is processed as a condenser lens, so that the position directly above the emission part 18 is fixed. Hold.
- FIG. 2 is a side view of the support frame 12.
- FIG. 1A to 1D and 2 the support frame 12, plate mirror 23 and rotary mirror 25 will be described.
- the upright plate portion 13b of the support frame 12 has an inclined groove 30 and a through hole 31.
- the inclined groove 30 has a rectangular cross section and opens obliquely rearward upward along the side contour of the standing plate portion 13b.
- the bottom surface of the inclined groove 30 is formed with an inclined surface inclined at 45° with respect to the substrate 15 .
- the through hole 31 is formed as a cylindrical hole penetrating through the standing plate portion 13b in the Y-axis direction.
- the center of the width of the inclined surface (bottom surface) of the inclined groove 30 (length in side view in FIG. 1B) is located at the same position as the emitting portion 18 of the VCSEL 17 .
- the center line Co of the cylindrical hole of the through hole 31 is positioned between the VCSEL 17 and the rotating mirror 21 of the MEMS optical deflector 20 in the X-axis direction.
- the center of the length of the inclined surface of the inclined groove 30 and the center line of the cylindrical hole of the through hole 31 are located at the same position in the Z-axis direction, that is, at the same height from the substrate 15 .
- the plate-like mirror 23 is made of a rectangular plate-like member, and has one end portion adhered to the inclined surface portion of the inclined groove 30 in a cantilevered state with an adhesive member such as resin.
- the plate thickness of the plate-like mirror 23 is set substantially equal to the depth of the inclined groove 30 .
- the plate width of the plate-like mirror 23 (length in side view in FIG. 1B) is slightly shorter than the width of the inclined groove 30 (length in side view in FIG. 1B). Therefore, before one end of the plate-like mirror 23 is adhered to the inclined groove 30, that is, before the one end is fixed, the plate-like mirror 23 is slightly displaceable in the direction of the slope of the bottom surface within the inclined groove 30. In addition, the angle of rotation around the axis parallel to the Y-axis can be changed. Such a change makes it possible to adjust the orientation of the mirror surface of the plate-like mirror 23 when the optical scanning device 10 is manufactured. By bonding one end of the plate-like mirror 23 to the inclined groove 30, it is fixed so that it cannot be displaced.
- the rotary mirror 25 has a flat mirror portion 26 and a cylindrical fitting end portion 27 that is coupled to one end portion of the mirror portion 26 and fits into the through hole 31 .
- the diameter of the fitting end portion 27 is slightly smaller than the diameter of the through hole 31 . Therefore, before the fitting end portion 27 is adhered to the through hole 31 , that is, before being fixed, the rotary mirror 25 fits the fitting end portion 27 into the through hole 31 while adjusting the center line of the through hole 31 . , and can be tilted within a predetermined tilt angle range from a state in which the center line of the rotary mirror 25 is aligned with the center line Co (FIG. 1B) of the through hole 31 .
- Such a rotatable and tiltable configuration enables adjustment of the orientation of the mirror surface as the lower surface of the mirror portion 26 during the manufacture of the optical scanning device 10, and then the fitting end portion 27 is adhered with resin or the like. A member is adhered so that it can be fixed so as not to rotate.
- the rotary mirror 21 of the MEMS optical deflector 20 is not positioned directly below the rotary mirror 25 but is positioned on the front side, that is, on the negative side of the rotary mirror 25 in the X-axis direction. there is In other words, the rotating mirror 21 of the MEMS optical deflector 20 is positioned obliquely downward when viewed from the rotating mirror 25 .
- this configuration contributes to making the light beam Lp emitted from the optical scanning device 10 obliquely forward rather than perpendicular to the substrate 15 .
- the optical scanning device 10 is attached to the temple of the eyeglass body as a spectacles-type video display device 155 (smart glasses video scanning device), which will be described as an example of use of the optical scanning device 10 in FIG.
- a spectacles-type video display device 155 smart glasses video scanning device
- FIG. 3 is a diagram showing a spectacles-type image display device 155 as an application example of the optical scanning device 10.
- the glasses-type image display device 155 will be briefly described.
- the spectacles-type image display device 155 includes a spectacles main body 160 and the video generation device 110 detachably attached to the spectacles main body 160 with an attachment member such as a clip 170 .
- the eyeglass body 160 includes left and right temples 161a and 161b, and a front frame 163 that is coupled to the front ends of the left and right temples 161a and 161b at both left and right ends.
- the front frame 163 further includes left and right lens frame portions 164a and 164b, and a bridge 165 connecting the left and right lens frame portions 164a and 164b.
- the optical scanning device 10 is incorporated in the image generating device 110 along the extension direction of the temple 161b of the spectacle body 160 along with other elements (eg, MEMS sensor buffer amplifier and LDD (laser driver)) arranged in a row.
- the optical scanning device 10 is arranged in the forefront, that is, closest to the lens 167 side.
- the light beam Lp (FIG. 1B or FIG. 4A) emitted from the optical scanning device 10 scans the scanning region 172 as the region on the inner surface side of the lens 67 .
- the scanning area 172 is a half mirror, and the light beam Lp is reflected by the scanning area 172 to generate an image on the user's retina as a screen.
- the cover 33 extends along the contour of the upright plate portion 13b above the base plate 15, covers the upright plate portion 13b, and is fixed to the peripheral edge of the bottom plate portion 13a at the lower end side opening peripheral edge. be.
- the cover 33 has a transparent portion 34 at least in a portion where a light beam Lp, which will be described later, is emitted from the optical scanning device 10 as scanning light.
- FIG. 4A is a detailed view of the positional relationship of the optical elements of the optical scanning device 10 in which the optical path of the light beam Lp is arranged;
- FIG. 4B is a view from the arrow 4B in FIG. 4A;
- FIG. 4D is a view on arrow 4D of FIG. 4A, and
- FIG. 4E is a view on arrow 4E of FIG. 4A.
- FIG. 4C is also a view along arrow 4C' in FIG. 4A.
- the arrows 4B-4E and 4C' in FIG. 4A are both located on the optical axis Cl.
- the right side of the drawing is forward in the negative direction of the X axis, and the left side is backward in the positive direction of the X axis.
- the condensing lens 19 and the plate-like mirror 23 are arranged directly above the output section 18 .
- the plate-like mirror 23 faces obliquely downward toward the rotating mirror 25 .
- the shielding plate 41 has an elliptical aperture 42 and is fixed (eg, glued) to the mirror surface of the plate-like mirror 23 .
- the mirror surface of the plate-like mirror 23 allows the light beam Lp to enter and exit only within the range of the elliptical aperture 42 .
- the condenser lens 19 is positioned between the light beam Lp and the plate-like mirror 23 in the optical path of the light beam Lp.
- the light is emitted so as to converge on a predetermined point downstream of 20 (light spot 51 on projection screen 50 in this example).
- the light beam Lp advances to the predetermined point while shrinking in the light radial direction.
- the mirror surface of the mirror portion 26 faces obliquely downward toward the plate-like mirror 23 side.
- the optical axis Cl extends parallel to the substrate 15 between the plate-like mirror 23 and the mirror section 26 .
- the shield plate 45 has an elliptical aperture 46 and is fixed (eg, glued) to the mirror surface of the mirror section 26 .
- the light beam Lp is incident only within the range of the elliptical aperture 46 on the mirror surface of the mirror portion 26 of the rotary mirror 25 .
- the plate-like mirror 23 has a mirror surface on the lower surface.
- a shielding plate 41 has an elliptical aperture 42 and is fixed to the mirror surface of the plate-like mirror 23 .
- the mirror surface of the plate-like mirror 23 allows the light beam Lp to enter and exit only within the range of the elliptical aperture 42 .
- a light spot 51 is generated on the projection screen 50 as a condensing point of the light beam Lp by the condensing lens 19 .
- the projection screen 50 is located at a predetermined distance from the optical scanning device 10 along the optical path of the light beam Lp. In the optical scanning device 10 installed in the glasses-type image display device 155 (FIG. 3), the projection screen 50 becomes the user's retina.
- the light beam Lp emitted from the emitting portion 18 of the VCSEL 17 is laser light sufficiently weakened so as not to harm human eyes.
- the light beam Lp is emitted from the emitting portion 18 of the VCSEL 17 while spreading radially upward (positive direction in the Z-axis direction) perpendicular to the substrate 15 .
- the light beam Lp advances along the optical path while contracting in the radial direction until it reaches the condensing point of the condensing lens 19 (the light spot 51 in this optical scanning device 10).
- the light beam Lp passes through the elliptical aperture 42 of the shielding plate 41 and reaches the plate-like mirror 23 .
- the elliptical aperture 42 is an ellipse when viewed from the direction perpendicular to the shielding plate 41 (the direction of the normal to the plate-like mirror 23), as shown in FIG. 4B.
- the shielding plate 41 has a surface inclined with respect to the optical axis Cl.
- the long axis of the elliptical aperture 42 overlaps the optical axis Cl of the beam Lp when viewed from the direction perpendicular to the shielding plate 41 (normal direction).
- Da1, Db1 are the major and minor axis dimensions of this ellipse.
- Da1/Db1 is defined as ⁇ 1.
- the elliptical aperture 42 is perpendicular to the shielding plate 41 (normal line It is closer to a perfect circle than viewed from the direction). That is, when the elliptical aperture 42 is viewed from the direction of the optical axis Cl, the ratio of the major axis to the minor axis of the ellipse in FIG. 4C (in FIG. 4C, the elliptical aperture 42 is an ellipse including a perfect circle) is It is a circle closer to 1 than ⁇ 1 (1 ⁇ 1).
- the vertical axis is the long axis and the horizontal axis is the short axis.
- ⁇ 1 is defined as the diameter of a circle (in the case of an ellipse, the average value of the major and minor axes) when viewed along the optical axis Cl.
- the light beam Lp emitted from the emitting portion 18 of the VCSEL 17, passed through the condenser lens 19 and condensed is almost a perfect circle at any position on the optical axis Cl when viewed in the direction of the optical axis Cl. shape (Fig. 4C).
- the light beam Lp generates an elliptical irradiation shape Lp1 at the shielding plate 41 arranged obliquely with respect to the optical axis Cl (FIG. 4B).
- the elliptical aperture 42 is an ellipse that is substantially similar in shape to the illumination shape Lp1 but slightly smaller. Also, the elliptical aperture 42 is included inside the irradiation shape Lp1. By doing so, the light beam Lp retains its original shape close to a perfect circle when viewed from the direction of the optical axis Cl even after being reflected by the plate-like mirror 23 and passing through the elliptical aperture 42. .
- the elliptical aperture 42 substantially similar to the irradiation shape Lp1 is limited to the case where the shielding plate 41 is thin. When the thickness is considered, the shape is slightly deformed from the similar shape. In addition, since the tilt angle of the plate-like mirror 23 is adjusted as described above, the tilt angle of the fixed shielding plate 41 changes, and the exact shape of the irradiation shape Lp1 is determined after the adjustment. For this reason, the relationship between the shape of the elliptical aperture 42 and the illumination shape Lp1 may deviate from similarity, but the direction of the major axis is always the direction of inclination of the shielding plate 41 with respect to the optical axis Cl. Also, the ellipse of the elliptical aperture 42 and the ellipse of the irradiation shape Lp1 have the same intersection point of the long axis and the short axis as the central position (FIG. 4B).
- a predetermined value ⁇ 1 is defined for the illuminance ⁇ in the cross section.
- the irradiation shape Lp1 is defined as a region where the illuminance ⁇ is equal to or greater than a predetermined value ⁇ 2 (0 ⁇ 2 ⁇ 1).
- the predetermined values ⁇ 1 and ⁇ 2 are 0.5 and 0.3 times the maximum value of the illuminance ⁇ , respectively.
- the illuminance of the light spot 51 on the projection screen 50 is assumed to be the illuminance generated by converging the incident points of the light rays on the projection screen 50 to the light spot 51 .
- the light beam Lp is cut in the peripheral region in the cross section, in other words, in the radially outer region where the illuminance ⁇ is less than ⁇ 1.
- the area inside the irradiation shape Lp1 and outside the elliptical aperture 42 in FIG. 4B is the area to be cut.
- the light beam Lp immediately after being reflected by the plate-like mirror 23 and emitted from the elliptical aperture 42 becomes a light beam with an illuminance ⁇ of ⁇ 1 or more and a circular cross section.
- the light beam Lp then travels along the optical path towards the rotating mirror 25 .
- the light beam Lp then passes through the elliptical aperture 46 of the shielding plate 45 and reaches the rotating mirror 25 .
- the elliptical aperture 46 is an ellipse when viewed from the direction perpendicular to the shielding plate 45 (the direction of the normal to the rotary mirror 25) from the direction of the optical axis Cl. (Fig. 4D).
- the irradiation shape Lp2 of the irradiation area of the light beam Lp within the elliptical aperture 46 is an ellipse and is generated inside the ellipse of the elliptical aperture 46 .
- the elliptical aperture 46 When viewed in the optical axis direction from the upstream side (plate-shaped mirror 23 side) and the downstream side (MEMS optical deflector 20 side) (FIG. 4E), the elliptical aperture 46 is more circular than it is when viewed from the vertical direction. It is circular, that is, the ratio of the major axis to the minor axis is closer to 1 than ⁇ 2. Let the diameter ⁇ of this circle be ⁇ 2. ⁇ 1> ⁇ 2.
- the shapes of the ellipses are not similar. Therefore, even though the elliptical apertures 42 and 46 are both circular when viewed from the direction of the optical axis Cl, it is possible to set ⁇ 1 ⁇ 2.
- the larger the angle of inclination of the light beam Lp with respect to the optical axis Cl (the direction perpendicular to the optical axis Cl is defined as the angle of inclination 0°), the more elliptical the aperture the shielding plate is arranged. It is preferable to lengthen the major axis of , that is, to increase the dimensional ratio ⁇ .
- the light beam Lp passes through the elliptical aperture 46 and then irradiates the rotary mirror 25 in an irradiation shape Lp2.
- the irradiation shape Lp2 is an elliptical shape that is smaller than the elliptical aperture 46 .
- the light beam Lp generates diffracted light when passing through the elliptical aperture 42 of the shielding plate 41 .
- the diffracted light is weak light that spreads over a wider range than the light beam Lp.
- the shielding plate 45 prevents the diffracted light from being reflected by the rotary mirror 25 .
- the illumination shape Lp2 is smaller than the elliptical aperture 46, and the entirety of the illumination shape Lp2 can be accommodated inside the elliptical aperture 46, thereby preventing further diffracted light from being generated from the shielding plate 45.
- the light beam Lp emitted from the elliptical aperture 46 travels obliquely downward (direction away from the plate-like mirror 23 in the X-axis direction) and reaches the center of the rotating mirror 21 of the MEMS optical deflector 20 .
- the rotating mirror 21 of the MEMS optical deflector 20 rotates around two mutually intersecting axes with non-resonance and resonance, respectively.
- the two axes are parallel to the X-axis and the Y-axis, respectively, when the rotating mirror 21 is stationary.
- the light beam Lp emitted from the rotating mirror 21 becomes scanning light for two-dimensional scanning due to the reciprocating rotation of the rotating mirror 21 about two axes.
- the resonant frequency and the non-resonant frequency are, for example, 14 kHz or higher and 60 Hz, respectively.
- the (non-co-advance side) reciprocating rotation angle of the rotating mirror 21 about the X-axis is smaller than the (co-advancing side) reciprocating rotation angle of the rotating mirror 21 about the Y-axis.
- the reciprocating rotation of the rotatable mirror 21 about the resonance axis and the reciprocating rotation of the rotatable mirror 21 about the non-resonant axis respectively correspond to the horizontal and vertical directions of the projection screen 50, which will be described later. described as.
- the light beam Lp is reflected by the rotating mirror 21 to become scanning light, emitted from the optical scanning device 10 , and scanned on the projection screen 50 outside the optical scanning device 10 .
- a light spot 51 is generated at the irradiation point of the light beam Lp on the projection screen 50 .
- a light spot 51 scanning over the projection screen 50 produces a rectangular image area with long and short sides in the horizontal and vertical directions, respectively.
- the area of the elliptical aperture 42 on the upstream side is larger than that of the elliptical aperture 46 on the downstream side.
- Both the elliptical apertures 42 and 46 are circular when viewed from the upstream side in the direction of the optical axis Cl, but the diameter of this circle is larger for the upstream elliptical aperture 42 than for the downstream elliptical aperture 46. .
- the shaping effect of the cross section of the light beam Lp can be enhanced.
- the contrast between the light spot 51 and its surroundings can be increased more than the one-step edge cut.
- the shielding plates 41 and 45 are attached to the plate-like mirror 23 and the rotating mirror 25 by bonding or the like.
- the projection screen 50 is a plane perpendicular to the optical axis Cl with the MEMS optical deflector 20 stopped.
- the light spot 51 is designed so that the ratio of the long axis to the short axis approaches 1, with a perfect circle being ideal.
- the projection screen 50 may have a surface inclined with respect to the optical axis Cl in a state where the MEMS optical deflector 20 is stopped depending on the application and arrangement of members.
- the retina corresponds to the projection screen 50, and the optical axis Cl of the light beam Lp with the MEMS optical deflector 20 stopped is tilted with respect to the assumed position of the retina. It is also possible that the optical scanning device 10 is placed at a position where it will be used.
- the formed light spot 51 is deformed into a shape extending in the direction of inclination of the optical axis Cl of the light beam Lp.
- Such deformation of the light spot 51 due to the position of the projection screen 50 may also occur in other applications such as projectors.
- a wall perpendicular to the plane on which the projector is placed can be assumed as the projection screen 50 .
- the light beam Lp emitted from the optical scanning device 10 has a cross-sectional shape perpendicular to the optical axis Cl toward the projection screen 50 assumed in advance. It is preferable to form an elliptical shape having a long axis in a direction perpendicular to the direction.
- FIG. 6 is a diagram showing the shape of the light spot 51 when the projection screen 50 is tilted with respect to the optical axis Cl.
- the tilt angle of the projection screen 50 is defined as 0° when the screen surface of the projection screen 50 is perpendicular to the optical axis Cl of the light beam Lp.
- the light beam Lp whose cross section perpendicular to the optical axis Cl is elliptical, becomes a perfect circle on the projection screen 50 . Even if the light beam Lp does not form an exact circle, the ratio of the major axis to the minor axis of the light spot 51 on the projection screen 50 can be brought close to one.
- a cross-sectional shape of the light beam Lp perpendicular to the optical axis Cl is called a cross-sectional shape.
- the cross-sectional shape of the light beam Lp can be shaped by adjusting the shapes of the elliptical aperture 42 of the shielding plate 41 and the elliptical aperture 46 of the shielding plate 45 .
- the contrast of the light spot 51 on the projection screen 50 is increased by cutting the periphery of the light beam Lp with the elliptical apertures 42,46. As a result, the quality of video viewed by the user can be improved.
- the diameter of the cross section of the light beam Lp is narrowed by the condensing by the condenser lens 19 (FIG. 4A). You may make it so. It should be noted that the condensing lens 19 is also used when parallel light is used.
- the number of VCSELs 17 is not limited to one, and for example, VCSELs 17 of three colors of RGB may be used side by side.
- a plate-like mirror 23 is arranged for each VCSEL 17 . Further, since the plate-like mirror 23 is a dichroic mirror, each VCSEL 17 can be aligned.
- shielding plates 41 and 45 are used, at least one shielding plate is sufficient in the present invention.
- FIG. 7 is a schematic diagram of the main part of the optical scanning device 61 equipped with VCSELs 17R, G, and B of RGB.
- the VCSELs 17R, G, B are mounted in a row in the X-axis direction on a common substrate 15 (FIG. 1A).
- a condensing lens 19 and a dichroic mirror 65 are arranged directly above each of the VCSELs 17R, G, and B so as to face each other.
- the light beam Lp is directed parallel to the substrate 15 toward the rotating mirror 25 , cut at the periphery by the elliptical aperture 46 of the shielding plate 45 , and then directed toward the MEMS optical deflector 20 .
- the optical scanning device 61 does not have the shielding plate 41 .
- the elliptical aperture 46 of the shielding plate 45 is smaller than the irradiation area of the light beam Lp on the shielding plate 45, and has the same function as the elliptical aperture 42 in the embodiment of FIG. 4 for shaping the light beam Lp.
- FIG. 5 is a configuration diagram of the main part of the optical scanning device 10 having a concave mirror 53 instead of the plate-like mirror 23.
- the concave mirror 53 is fixed (eg, glued) to the shielding plate 41 at its peripheral edge so as to face the elliptical aperture 42 from the upper surface side of the shielding plate 41 .
- the concave mirror 53 can also be manufactured by integral molding with the shielding plate 41 using a predetermined mold, for example.
- one end of the shielding plate 41 is extended toward the inclined groove 30 ( FIG. 2 etc.) and directly fixed to the inclined groove 30 .
- a VCSEL 17 is used as a light source.
- the light source of the present invention is not limited to the VCSEL 17, and other than the VCSEL 17, for example, an edge emitting laser can be selected.
- the VCSEL 17 emits light directly above the optical axis Cl.
- the light source does not have to emit the light beam upward (for example, right above).
- the plurality of optical path generation mirrors direct the light beam emitted from the light source to the mirror portion of the MEMS optical deflector. It is sufficient that an optical path is generated so as to make it incident.
- the shielding plates 41 and 45 are attached to the plate-like mirror 23 and the rotating mirror 25 as corresponding optical path generating mirrors.
- the shielding plate can also be arranged on the optical path upstream of the corresponding optical path generating mirror and away from the corresponding optical path generating mirror. In that case, the shielding plate arranged on the upstream side of the corresponding optical path generating mirror on the optical path and away from the corresponding optical path generating mirror must be disposed so as not to interfere with the optical path on the downstream side of the corresponding optical path generating mirror. .
- the shielding plates 41 and 45 are arranged parallel to the plate-like mirror 23 and the rotating mirror 25 as corresponding optical path generating mirrors.
- the concave mirror 53 in FIG. 5 has a curved mirror surface, the concept of parallelism to the shielding plate 41 cannot be defined.
- the normal line is set at the intersection of the incident side optical axis Cl and the shielding plate and the optical path generation mirror, and the shielding plate with respect to the incident side optical axis Cl and the normal to the optical path generation mirror are defined as the tilt angles of the shield plate and the optical path generation mirror.
- the tilt angle of the shield plate and the optical path generation mirror at that time is 0° when the tilt angle of the plane perpendicular to the light beam Lp at the intersection is defined as 0°.
- Optical scanning device 17... VCSEL, 19... Condensing lens, 20... MEMS optical deflector, 21... Rotary mirror, 23... Plate-like mirror (optical path generating mirror), 25... rotating mirror (optical path generating mirror), 41, 45... shielding plate, 42, 46... oval aperture, 53... concave mirror (optical path generating mirror).
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Abstract
Description
基板と、
前記基板上に実装され、光ビームを出射する光源と、
上面側がミラー面であるミラー部及び前記ミラー部を軸の回りに往復回動させるアクチュエータを有し、前記基板に実装されるMEMS光偏向器と、
前記光源から出射された前記光ビームが前記MEMS光偏向器の前記ミラー部に入射する光路を生成する少なくとも1つの光路生成ミラーと、
前記光路において前記光源からの出射光が最初に入射する光路生成ミラーとの間に配置される集光レンズと、
前記光路において前記光路生成ミラーのいずれかを対応光路生成ミラーとして前記対応光路生成ミラーの上流側にかつ前記光路の光軸に対して前記対応光路生成ミラーの傾斜する方向と同一の傾斜する方向で配置される第1の楕円形アパーチャを有する第1の遮蔽板と、
を備える。
図1Aは光走査装置10の平面図、図1Bは図1Aの1B矢視図、図1Cは図1Aの1C矢視図、図1Dは図1Aの1D矢視図である。なお、図1A-図1Dは、カバー33(図1Bの一点鎖線)を取り外した状態で光走査装置10を示している。
図4Aは、光ビームLpの光路の配設される光走査装置10の光学素子の位置関係の詳細図、図4Bは図4Aの4B矢視図、図4Cは図4Aの4C矢視図、図4Dは図4Aの4D矢視図、図4Eは図4Aの4E矢視図である。図4Cは、図4Aの矢視4C‘図でもある。なお、図4Aの矢視4B-4E及び矢視4C’は、いずれも光軸Cl上に位置する。
光ビームLpは、VCSEL17の出射部18から基板15に対して垂直で上向き(Z軸方向の正の向き)に径方向に広がりつつ、出射する。光ビームLpは、集光レンズ19を通過した後は、集光レンズ19の集光点(この光走査装置10では光スポット51)に達するまで径方向に縮小しつつ、光路に沿って進む。光ビームLpは、集光レンズ19の通過後、遮蔽板41の楕円形アパーチャ42を通過して、板状ミラー23に達する。
図5は、板状ミラー23に代えて凹面ミラー53を有する光走査装置10の主要部の構成図である。凹面ミラー53は、遮蔽板41の上面側から楕円形アパーチャ42に臨むように、遮蔽板41に周縁において固着(例:接着)されている。凹面ミラー53は、例えば、所定の型枠を用いて遮蔽板41と一体成型で製造することもできる。板状ミラー23に代えて凹面ミラー53を用いる場合、遮蔽板41の一端部が傾斜溝30(図2等)の方に延長されて、傾斜溝30に直接、固着される。
実施形態の光走査装置10では、光源としてVCSEL17が用いられている。本発明の光源は、VCSEL17に限定されず、VCSEL17以外にも例えば端面発光レーザ(Edge Emitting Laser)を選択することもできる。
Claims (7)
- 基板と、
前記基板上に実装され、光ビームを出射する光源と、
上面側がミラー面であるミラー部及び前記ミラー部を軸の回りに往復回動させるアクチュエータを有し、前記基板に実装されるMEMS光偏向器と、
前記光源から出射された前記光ビームが前記MEMS光偏向器の前記ミラー部に入射する光路を生成する少なくとも1つの光路生成ミラーと、
前記光路において前記光源からの出射光が最初に入射する光路生成ミラーとの間に配置される集光レンズと、
前記光路において前記光路生成ミラーのいずれかを対応光路生成ミラーとして前記対応光路生成ミラーの上流側にかつ前記光路の光軸に対して前記対応光路生成ミラーの傾斜する方向と同一の傾斜する方向で配置される第1の楕円形アパーチャを有する第1の遮蔽板と、
を備えることを特徴とする光走査装置。 - 請求項1記載の光走査装置において、
前記第1の遮蔽板は、前記対応光路生成ミラーに取り付けられ、
前記第1の遮蔽板の前記第1の楕円形アパーチャは、前記光路において前記対応光路生成ミラーに対して下流側から前記光軸方向から見たときに、前記第1の遮蔽板を垂直方向から見たときよりも長軸と短軸の比が1に近い円形であることを特徴とする光走査装置。 - 請求項1又は2記載の光走査装置において、
さらに、前記光路上に前記第1の遮蔽板より下流側に、第2の楕円形アパーチャを有する第2の遮蔽板を備え、
各遮蔽板における楕円形アパーチャの長軸と短軸との比は、相互に相違していることを特徴とする光走査装置。 - 請求項3記載の光走査装置において、
前記第2の遮蔽板の前記楕円形アパーチャのアパーチャ面積は、前記第1の遮蔽板の前記楕円形アパーチャのアパーチャ面積より小さいことを特徴とする光走査装置。 - 請求項1~4のいずれか1項に記載の光走査装置において、
前記光路生成ミラーの少なくとも1つは、凹面ミラーであることを特徴とする光走査装置。 - 請求項1又は2記載の光走査装置において、
さらに、前記光路上の前記第1の遮蔽板より下流側に第2のアパーチャを有する第2の遮蔽板が配設され、
前記第1の遮蔽板に対して前記光ビームは、前記第1の楕円形アパーチャよりも大きな照射領域を形成し、
前記第2の遮蔽板は、前記光ビームが第2のアパーチャの内側を通過する位置に配置されていることを特徴とする光走査装置。 - 光ビームを出射する光源と、
上面側がミラー面であるミラー部及び前記ミラー部を軸の回りに往復回動させるアクチュエータを有するMEMS光偏向器と、
前記光源から出射された前記光ビームが前記MEMS光偏向器の前記ミラー部に入射する光路に配置される第1のアパーチャを有する第1の遮蔽板と、
前記光路上で前記第1の遮蔽板より下流側に配置される第2のアパーチャを有する第2の遮蔽板と、
を備え、
前記第1の遮蔽板に対して前記光ビームは、前記第1のアパーチャよりも大きな照射領域を形成し、
前記第2の遮蔽板は、前記光ビームが第2のアパーチャの内側を通過する位置に配置されていることを特徴とする光走査装置。
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JP2017207630A (ja) | 2016-05-18 | 2017-11-24 | スタンレー電気株式会社 | 光偏向器 |
JP2018116219A (ja) * | 2017-01-20 | 2018-07-26 | 株式会社Qdレーザ | 画像投影装置 |
JP2019211705A (ja) * | 2018-06-07 | 2019-12-12 | 株式会社リコー | 光学装置、映像表示装置、及び検眼装置 |
JP6734532B2 (ja) | 2016-04-22 | 2020-08-05 | ミツミ電機株式会社 | 表示装置 |
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US5347121A (en) * | 1992-12-18 | 1994-09-13 | Spectra-Physics Scanning Systems, Inc. | Variable focus optical system for data reading |
JP4512330B2 (ja) | 2002-07-12 | 2010-07-28 | 株式会社リコー | 複合光学素子、及び光トランシーバー |
JP2009027088A (ja) | 2007-07-23 | 2009-02-05 | Fuji Xerox Co Ltd | 半導体発光装置 |
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JP6734532B2 (ja) | 2016-04-22 | 2020-08-05 | ミツミ電機株式会社 | 表示装置 |
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JP2018116219A (ja) * | 2017-01-20 | 2018-07-26 | 株式会社Qdレーザ | 画像投影装置 |
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