JP2012252068A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a scanning field angle without decreasing image resolution and ranging accuracy and without increasing magnitude of a driving signal.SOLUTION: An optical scanner comprises: first scanning means 2 that comprises a first movable plate 2c including a first light reflecting surface 2a, is arranged so that a reflection point of the first light reflecting surface 2a, when projected to a reference plane including an ellipse, coincides with one focus F1 of the ellipse, and reflects and scans incident light entering the first reflecting surface 2a by oscillation of the first movable plate 2c; an elliptical mirror 4 that includes a reflecting surface 4a which is curved along the arc of the ellipse on the long axis side, and reflects incident light from the first scanning means 2; second scanning means 3 that comprises a second movable plate 3c including a second light reflecting surface 3a, and that is arranged so that a reflection point of the second light reflecting surface 3a, when projected to the reference plane, coincides with the other focus F2 between the focus F1 and the elliptical mirror 4 and so as to be located opposite to the first scanning means 2 with respect to the reference plane; and driving means 5 that supplies driving signals to each scanning means.

Description

  The present invention relates to an optical scanning device that two-dimensionally scans incident light within a target region.

  2. Description of the Related Art Conventionally, an optical scanning device that performs two-dimensional scanning with laser light within a target region is known. As this type of optical scanning device, for example, there is an optical scanning device configured to include a scanning unit configured by a two-dimensional galvanometer mirror or the like and a driving unit that drives the scanning unit to swing (for example, Patent Document 1). reference). This drive means applies two drive signals having frequencies near the resonance frequency around two swing axes (x-axis and y-axis) perpendicular to the movable plate included in the scanning means to the scanning means while giving a predetermined phase difference. As a result, the movable plate is driven to swing around the x-axis and the y-axis at a mechanical angle corresponding to the magnitude of each drive signal (for example, the magnitude of the current value).

  Here, this type of optical scanning device is, for example, an optical distance measuring device that measures a distance to an object existing in a measurement target region by two-dimensionally scanning laser light in the target region, or a laser scanning projector. The scanning angle of view is four times the maximum mechanical angle (one side) around each swing axis of the movable plate. That is, the scanning field angle in the optical scanning direction around the x axis is four times the maximum mechanical angle around the x axis, and the scanning field angle in the optical scanning direction around the y axis is 4 times the maximum mechanical angle around the y axis. Is double.

JP-A-7-175005

  Incidentally, in the optical scanning device described in Patent Document 1, the scanning field angle of the target area of the optical distance measuring device and the projection surface of the projector, particularly the horizontal scanning field angle, is increased so that a wide range of optical scanning is possible. It is requested to do. In order to satisfy this requirement, in the conventional optical scanning device, for example, the optical scanning direction around the x-axis of the movable plate coincides with the horizontal direction of the target area in the optical distance measuring device, and the projection plane in the projector is horizontal. The scanning means is arranged so as to coincide with the direction, and the magnitude of the driving signal for rotating around the x axis (for example, the magnitude of the driving current value) inputted from the driving means to the scanning means is increased around the x axis of the movable plate. The scanning angle of view is increased by increasing the mechanical angle.

  However, in the conventional optical scanning device, when the mechanical angle is increased by increasing the magnitude of the drive signal to increase the scanning angle of view, the oscillation exceeds the mechanical strength of the oscillation shaft of the two-dimensional galvanometer mirror. Since the mechanical angle around the axis cannot be increased, there is a problem that there is a limit to increasing the scanning angle of view.

  The present invention has been made paying attention to such a problem, and an object of the present invention is to provide an optical scanning device capable of increasing a scanning field angle without increasing the magnitude of a drive signal.

  An optical scanning device according to an aspect of the present invention includes a first movable plate that has a first light reflecting surface and is configured to be swingable about a first swing axis, and the first movable plate swings. The first scanning means for reflecting and scanning the light incident on the first light reflecting surface from the light source, the light scanning direction of the first scanning means is curved into an arc shape on the long axis side of the ellipse, An elliptic mirror that reflects the light incident from the first scanning means, and a second light reflecting surface that has a reflection surface extending from the arc shape in a direction orthogonal to the light scanning direction of the one scanning means And a second movable plate formed so as to be capable of swinging around a second swing shaft, and the second movable plate swings so that the light from the elliptical mirror is transmitted to the light of the first scanning means. Second scanning means for reflecting and scanning in a direction orthogonal to the scanning direction, and each of the first and second movable plates are swung. Drive means for supplying a drive signal for swinging around to the first and second scanning means, respectively, and a reflection point on the first light reflection surface as seen from a direction perpendicular to a reference plane including the ellipse. The first scanning means is arranged so that a point projected on the reference plane coincides with one focal point of the ellipse, and a reflection point on the second light reflection surface is viewed from the direction perpendicular to the reference plane. The second scan so that a point projected on a plane coincides with the other focus located between the one focal point and the elliptical mirror and is located on the opposite side of the first scanning means with respect to the reference plane. Means are arranged.

  According to the optical scanning device of the present invention, the point obtained by projecting the reflection point of the first light reflection surface onto the reference plane including the ellipse that forms the curved shape of the reflection surface of the elliptical mirror coincides with one focal point of the ellipse. The first scanning means is disposed, the point where the reflection point of the second light reflecting surface is projected on the reference plane coincides with the one focal point and the other focal point located between the ellipsoidal mirrors, and the first scanning means is located with respect to the reference plane. Since the second scanning unit is arranged so as to be located on the side opposite to the one scanning unit, the light incident from one focal point of the elliptical mirror toward the reflection surface of the elliptical mirror is directed to the other focal point of the elliptical mirror. By utilizing the characteristic of the elliptical mirror that collects light, the scanning field angle of the light reflected by the second light reflecting surface can be made larger than the scanning field angle determined by the mechanical angle of the first scanning means. Thus, since the magnitude of the drive signal may be the same as the conventional one, the scanning angle of view can be increased without increasing the magnitude of the drive signal. In addition, when the same scanning angle of view as in the prior art may be used, the drive signal can be made smaller than in the prior art, so that power can be saved.

1 is a perspective view showing a schematic configuration of a first embodiment of an optical scanning device according to the present invention. It is a block diagram which shows schematic structure of the optical scanning device of the said embodiment. It is a perspective view of the elliptical mirror of the said embodiment. It is a figure explaining the expansion condition of the scanning angle of view of the scanning apparatus of the said embodiment, and is the figure which showed the light collection condition when it sees from the B direction shown in FIG. It is the elements on larger scale of the optical scanning device 1 shown in FIG. 1, and is the figure which showed the condition where the light collecting point shifted | deviated during the rocking | fluctuation of the 1st movable part. It is a figure which shows the structure of the one-dimensional galvanometer mirror as a 1st movable part of the said embodiment, and a 2nd movable part. It is a perspective view which shows schematic structure of 2nd Embodiment of the optical scanning device based on this invention. It is C-C 'arrow sectional drawing of the optical scanning device of the said 2nd Embodiment. It is a perspective view which shows the modification of the optical scanning device of the said embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a schematic configuration of the optical scanning device according to the first embodiment of the present invention, and FIG. 2 is a block diagram showing a schematic configuration of the optical scanning device of the present embodiment. The optical scanning device 1 performs two-dimensional scanning by reflecting and scanning incident laser light. In the following description, the case where the optical scanning device 1 is used as an optical scanning unit of an optical distance measuring device that measures the distance to an object existing in the target region by two-dimensionally scanning the laser light in the target region will be described. .

  As shown in FIG. 1, the optical scanning device 1 according to the present embodiment includes an electromagnetically driven first scanning means 2 that reflects and scans incident laser light, and incident laser light that is emitted from the first scanning means 2. Electromagnetically driven second scanning means 3 that performs reflection scanning in a direction orthogonal to the scanning direction, an elliptical mirror 4, and driving means 5 that drives the first scanning means 2 and the second scanning means 3 (see FIG. 2, FIG. 1) Is omitted). The optical scanning unit 6 shown in FIG. 2 includes the first scanning unit 2, the second scanning unit 3, and the elliptical mirror 4, and is a main part that scans the laser beam. In FIG. 1, for the sake of simplification, the fixing portion 31 shown in FIG. 6 described later is omitted.

As shown in FIG. 1, the first scanning means 2 includes a first movable plate 2c having a flat plate-like first light reflecting surface 2a and swingable about a first swing shaft 2b. by first movable plate 2c is swung, and is configured to be incident on the ellipsoidal mirror 3 light incident from the light source to the first light reflecting surface 2a is reflected scanning at a scan angle theta _1. As such first scanning means 2, for example, a one-dimensional scanning semiconductor galvanometer mirror (hereinafter simply referred to as “one-dimensional galvanometer mirror”) described in Japanese Patent No. 2722314 proposed by the present applicant is used. Can be used. Then, as shown in FIG. 1 and FIG. 4 to be described later, the first scanning unit 2 uses the center point 2d, which is a reflection point on the first light reflection surface 2a, as viewed from the vertical direction of the reference plane including the ellipse. Is arranged so that the point projected onto the point coincides with one of the focal points F1 of the ellipse. In the present embodiment, the first scanning means 2 is arranged so that the light scanning direction (X direction) around the first swing axis 2b coincides with the horizontal direction of the target area of the optical distance measuring device. .

  As shown in FIG. 1, the second scanning means 3 has a flat plate-like second light reflecting surface 3a and is formed to be swingable around a second swing shaft 3b orthogonal to the first swing shaft 2b. The second movable plate 3c is provided, and the second movable plate 3c swings so that the light from the elliptical mirror 4 is in a direction (Y direction) orthogonal to the light scanning direction (X direction) of the first scanning means 2. It is configured to perform reflection scanning. As the second scanning unit 3, for example, the above-described one-dimensional galvanometer mirror can be used similarly to the first scanning unit 2. As shown in FIGS. 1 and 4, the second scanning unit 3 has a point in which a center point 3 d that is a reflection point on the second light reflecting surface 3 a as viewed from the direction perpendicular to the reference plane is projected on the reference plane. Is arranged so as to coincide with the other focal point F2 located between the focal point F1 and the elliptical mirror 4 and on the opposite side of the first scanning means 2 with respect to the reference plane as shown in FIG. .

  The elliptical mirror 4 reflects the light incident from the first scanning means 2, and the optical scanning direction of the first scanning means 2 is curved into an arc shape on the long axis A1 side of the ellipse, and the first scanning is performed. About the direction orthogonal to the optical scanning direction of the means 2, it has the reflective surface 4a of the shape which extended circular arc shape. That is, as shown in FIG. 1, the reflecting surface 4a is perpendicular to the reference plane including the ellipse, with a part A of the arc on the major axis A1 side of the ellipse (the broken line portion indicated by a thick line in FIG. The surface is formed in a shape obtained when the arc is simply shifted. The elliptical mirror 4 has two focal points, and collects light emitted from one focal point F1 toward the reflecting surface 2a at the other focal point F2 which is a focal point on the elliptical mirror 4 side. Have. In FIG. 1, the elliptical mirror 4 shows only the reflecting surface 4a for simplification of the drawing, but actually has a thickness as shown in FIG.

  Here, in order to use the above-mentioned light collecting characteristics of the elliptical mirror 4, the point where light is emitted toward the reflecting surface 4a and the point where the light reflected by the reflecting surface 4a is collected are represented by an ellipse. Although it is a general precondition that it is positioned on the same plane as the reference plane that includes it, an elliptical mirror can be used as long as the following positional relationship is satisfied even if the emission point and the light collection point are not positioned on the same plane: 4 light collecting characteristics can be used. That is, the point where the exit point is projected onto the reference plane when viewed from the vertical direction of the reference plane coincides with one of the focal points F1 of the ellipse, and the point where the light collection point is projected onto the reference plane when viewed from the vertical direction of the reference plane In this case, the elliptical mirror 4 also has a positional relationship that coincides with the other focal point F2 located between the focal point F1 and the elliptical mirror 4 and satisfies the positional relationship that the reference plane is located between the emission point and the light collecting point. Light collecting characteristics can be used.

  In this embodiment, as shown in FIGS. 1 and 4, a point obtained by projecting the center point 2d of the first light reflecting surface 2a on the reference plane as a point for emitting light toward the reflecting surface 2a is one focal point F1. The point where the center point 3d of the second light reflecting surface 3a as the point where the light reflected by the reflecting surface 2a is collected is projected on the reference plane is the other located between the one focal point F1 and the elliptical mirror 4 Of the first scanning means 2 and the second scanning so that the reference plane is located between the center point 2d of the first light reflecting surface 2a and the center point 3d of the second light reflecting surface 3a. Means are arranged. Thereby, the light reflected at the center point 2 d of the first scanning means 2 is collected at the center point 3 d of the second scanning means 3 via the elliptical mirror 4.

FIG. 4 is a diagram for explaining an enlarged state of the scanning angle of view θ ₂ of the optical scanning device 1 in the present embodiment. The mechanical angle φ around the first swing axis 2 b of the first scanning means 2 is the maximum (φ _max ). It is the figure which showed the light collection condition when it sees from the B direction of FIG. 1 which shows a perpendicular | vertical direction with respect to a reference plane at the time. As can be seen from this figure, the light incident on the center point 2d of the first light reflecting surface 2a is reflected and scanned and incident on the elliptical mirror 4 when the first movable plate 2c swings. The light incident on the elliptical mirror 4 is collected at the center point 3d of the second light reflecting surface 3a. In this case, the angle θ of the optical path of light traveling from the first scanning unit 2 into an elliptical mirror 4 makes with the long axis A1 of the ellipsoidal mirror 4 equal to twice the maximum mechanical angle phi _max, the maximum mechanical angle phi _max Four times is the scanning angle θ ₁ (see FIG. 1) of the first scanning means 2. Then, twice the angle θ ′ formed by the optical path of light from the elliptical mirror 4 to the second scanning means 3 with respect to the major axis A1 of the elliptical mirror 4 is the horizontal scanning field angle θ ₂ in the target area (see FIG. 1). ) That is, θ ₁ , θ and φ _max , and θ ₂ and θ ′ are in a relationship satisfying the following expressions (1) and (2), respectively.
θ ₁ = 2θ = 4φ _max (1)
θ ₂ = 2θ ′ (2)
Here, as can be seen from FIG. 4, the angle θ ′ is larger than the angle θ. As a result, the horizontal scanning angle of view θ ₂ (= 2θ ′) of the light reflected by the second light reflecting surface 4a and emitted into the target region is set to the maximum mechanical angle φ _max around the first swing axis 2b. Can be made larger than the scanning field angle determined by, that is, the scanning angle θ ₁ (= 2θ).

Here, if the center point 2d, 3d and focus F1, F2 satisfy the positional relationship described above, between the scanning angle theta ₁ and the scanning field angle theta _2, comprises the relationship satisfying the following equation (3) Tatsu.
_{L1 × tan (θ 1/2} ) = L2 × tan (θ 2/2) ··· (3)
However, as shown in FIG. 4, L1 is the direction of the long axis A1 of the optical path length of the light from the first scanning means 2 toward the elliptical mirror 4 when the mechanical angle φ of the first scanning means 2 is maximum (φ _max ). L2 is the length of the optical path length of the light from the elliptical mirror 4 toward the second scanning means 3 when the mechanical angle φ of the first scanning means 2 is maximum (φ _max ). The length of the component. For example, the scanning angle theta ₁ of the first scanning means 2 in the case of 30 °, in this case, the ratio of L1 and L2 is L1: L2 = 2: the curved shape of the reflecting surface 2a is designed to be 1 When the elliptical mirror 4 is used, the scanning field angle θ ₂ is about 56.3 ° from the above equation (3), and is determined by the maximum mechanical angle φ _max around the first swing axis 2b. (Ie, θ ₁ = 30 °) is enlarged about 1.8 times.

The scanning field angle magnification factor K (= θ ₂ / θ ₁ ) has been described in the case of about 1.8 times. However, the magnification factor K is not limited to this, and the shape of the elliptical mirror 4 is as follows. In the following equation (5), which satisfies the ellipse formula shown in equation (4) and θ ₁ and θ ₂ are the sum of the distances from the two focal points to the ellipse is twice the major axis of the ellipse: Any enlargement ratio K can be realized as long as the ellipse theorem shown is satisfied.
x ² / a ² + y ² / b ² = 1 (4)
W / (2 sin θ ₁ ) + W / ( ₂ sin θ ₂ ) = 2a (5)
Where x is a coordinate on the long axis A1 side in a two-dimensional coordinate having the origin at the intersection of the major axis A1 and the minor axis A2, and y is a two-dimensional coordinate having the origin at the intersection of the major axis A1 and the minor axis A2. Are the coordinates on the short axis A2 side, a is the major axis of the ellipse, and b is the minor axis of the ellipse. W is the effective width of the elliptical mirror 4, and when the mechanical angle φ around the first swing axis 2b of the first scanning means 2 is the maximum ( _φmax ), the first scanning means 2 to the elliptical mirror 4 This is twice the y coordinate of the point where the light enters (ie, y = W / 2).

FIG. 5 is a partially enlarged view of the optical scanning device 1 shown in FIG. 1, and shows an exaggerated view of the situation in which the light collecting point by the elliptical mirror 4 is shifted while the first scanning means 2 is oscillating. In FIG. 1, the scanning locus of the light reflected and scanned by the first scanning means 2 along the reflecting surface 2a of the elliptical mirror 4 is a partial arc A on the major axis A1 side of the ellipse (broken line portion indicated by a thick line). However, the actual scanning locus is like a real arc A ′ indicated by a one-dot chain line in FIG. 5 and does not completely match the arc A. Thus, since the actual scanning locus is deviated from the arc A, the light traveling from the elliptical mirror 4 toward the second scanning unit 3 is separated from the center point 3d by a distance corresponding to the mechanical angle φ of the first scanning unit 2. It is shifted and collected. That is, for example, when the mechanical angle φ of the first scanning unit 2 is the maximum (φ _max ), the light collecting point of the light (a1 or a2 in FIG. 5) incident on the elliptical mirror 4 from the first scanning unit 2; The amount of deviation from the center point 3d of the second scanning means 3 becomes the maximum, and as the mechanical angle φ of the first scanning means 2 becomes smaller, the amount of deviation becomes smaller and the mechanical angle φ of the first scanning means 2 becomes zero. At this time, the light collecting point of the light (a3 in FIG. 4) incident on the elliptical mirror 4 from the first scanning unit 2 coincides with the center point 3d of the second scanning unit 3. Thus, since the light collecting point on the second light reflecting surface 3a is shifted while the first scanning means 2 is oscillating, the scanning trajectory of the two-dimensional scanning in the target region is determined according to this shift. Further, the range in which two-dimensional scanning is possible is also determined according to the shift of the light collecting point. For example, when the optical scanning device 1 is used as an optical scanning unit of an optical distance measuring device, a two-dimensional scanable range determined according to the shift of the light collecting point is set to be wider than the target region, and the target region The projection timing of the laser light incident on the optical scanning device 1 may be set on the basis of the scanning locus determined according to the shift of the light collecting point so that each pixel set to 1 can be irradiated with the laser light.

  FIG. 6 shows the configuration of one-dimensional galvanometer mirrors 30 and 30 ′ as specific examples of the scanning means 2 and 3. In the present embodiment, a one-dimensional galvanometer mirror 30 (hereinafter referred to as “first galvanometer mirror 30”) as the first scanning means 2 and a one-dimensional galvanometer mirror 30 ′ (hereinafter referred to as “first galvanometer mirror 30”) as the second scanning means 3. The two galvanometer mirrors 30 '") are formed as separate bodies, but their basic configurations are the same. Each of the galvanometer mirrors 30 and 30 ′ is constituted by a frame-like fixed portion 31 and a pair of torsion bars 32 and 32 disposed inside the fixed portion 31 as the first swing shaft 2b or the second swing shaft 3b. And a movable plate 33 supported to be swingable. However, the dimensions and the like of the torsion bars 32 and 32 of the galvanometer mirrors 30 and 30 'are set according to the design specifications. In the present embodiment, the first galvanometer mirror 30 is arranged so that the optical scanning direction of the first galvanometer mirror 30 coincides with the horizontal direction of the target region, and the second galvanometer mirror 30 ′ is the second galvanometer mirror 30 ′. The torsion bars 32 and 32 are arranged so as to be orthogonal to the torsion bars 32 and 32 of the first galvanometer mirror 30.

  A mirror 34 as the first light reflecting surface 2 a or the second light reflecting surface 3 a is formed at the center of the movable plate 33, and a drive coil 35 is formed at the peripheral portion of the movable plate 33. The end of the drive coil 35 is connected to electrode terminals 36 and 36 formed on the fixed portion 31.

  Further, a pair of first permanent magnets 37, 37 that cause a magnetic field to act on the drive coil 35 are disposed to face each other with the fixed portion 31 interposed therebetween. The fixed portion 31, the torsion bars 32, 32, and the movable plate 33 are integrally formed from a semiconductor substrate.

Each galvanometer mirror 30, 30 ′ has a Lorentz force acting on the movable plate 33 due to an electric current (for example, an alternating current) flowing through the drive coil 35 and a magnetic field generated by the permanent magnets 37, 37. Swing in one dimension. In the first galvanometer mirror 30, the laser beam incident on the mirror 34 when the movable plate 33 oscillates is reflected and scanned at a scanning angle θ ₁ in the direction around the axis of the torsion bars 32, 32 as the first oscillating shaft 2 b. Is incident on the elliptical mirror 4. In the second galvanometer mirror 30 ′, the laser beam incident upon the swing of the movable plate 33 is reflected and scanned around the axis of the torsion bars 32, 32 as the second swing shaft 3b and emitted to the target region. The Thereby, the laser beam incident on the mirror 34 of the first galvanometer mirror 30 is two-dimensionally scanned in the target region. At this time, the horizontal scanning field angle θ ₂ of the target region is larger than the scanning angle θ ₁ .

  Returning to FIG. 2, the drive means 5 supplies a drive signal for swinging the galvanometer mirrors 30 and 30 ′ around the axes of the torsion bars 32 and 32 to the galvanometer mirrors 30 and 30 ′. For example, the driving circuit 5a is used. This drive circuit 5a matches the drive signal (for example, alternating current) for each galvanometer mirror 30, 30 'with the resonance frequency around the torsion bars 32, 32 of the movable plate 33 of each galvanometer mirror 30, 30'. Is supplied to the drive coil 35 via the electrode terminals 36 and 36 at the drive frequency set in the above. Hereinafter, the drive signal for the first galvanometer mirror 30 is referred to as a first drive signal, and the drive signal for the second galvanometer mirror 30 ′ is referred to as a second drive signal.

Next, the operation of the optical scanning device 1 having the above configuration will be described with reference to FIGS. In the following description, the scanning angle theta ₁ of the first galvano mirror 30 is 30 °, the ratio of L1 and L2 is L1: L2 = 2: described as an example the case 1.

First, the drive circuit 5a supplies the first drive signal to the drive coil 35 at the drive frequency initially set for the first galvanometer mirror 30, thereby causing the first galvanometer mirror 30 to rotate around the axes of the torsion bars 32, 32. Swing in the direction (horizontal direction). At the same time, the drive circuit 5 a supplies the second galvanometer mirror 30 ′ to the torsion bars 32, 32 by supplying the second drive signal to the drive coil 35 at the drive frequency initially set for the second galvanometer mirror 30 ′. Swing in the direction around the axis (vertical direction). Here, the light incident on the center point 2d of the mirror 34 of the first galvanometer mirror 30 is reflected and scanned and incident on the elliptical mirror 4 and incident on the elliptical mirror 4 as the movable plate 33 swings. The collected light is collected at substantially the center point 3d of the mirror 34 of the second galvanometer mirror 30 ′. The collected light is reflected and scanned by the mirror 34 and emitted to the target area when the movable plate 33 of the second galvanometer mirror 30 ′ is swung. Here, the angle θ ′ formed by the optical path of light from the elliptical mirror 4 to the second galvanometer mirror 30 ′ with respect to the major axis A 1 of the elliptical mirror 4 is determined by the optical path of light from the first galvanometer mirror 30 to the elliptical mirror 4. It becomes larger than the angle θ formed with respect to the long axis A1 of the elliptical mirror 4. At this time, the horizontal scanning field angle θ ₂ of the emitted light is about 56.3 ° from the above-described equation (3), and the scanning field angle θ ₂ depends on the maximum mechanical angle φ _max of the first galvanometer mirror 30. The image is enlarged to about 1.8 times the fixed scanning angle of view (that is, θ ₁ = 30 °).

As described above, according to the optical scanning device 1 according to the present embodiment, since the magnitude of the drive signal may be the same as the conventional one, the scanning field angle θ ₂ can be increased without increasing the magnitude of the drive signal. In addition, when the same scanning angle of view θ ₂ as in the prior art is sufficient, the drive signal can be made smaller than in the prior art, so that power can be saved. In the present embodiment, the first scanning unit 2 is arranged so that the optical scanning direction of the first scanning unit 2 coincides with the horizontal direction of the target region, and the horizontal scanning angle of view of the target region is increased. As described above, when the first scanning unit 2 is arranged so as to coincide with the vertical direction of the target region, the scanning field angle in the vertical direction can be increased.

Next, an optical scanning device according to a second embodiment of the present invention will be described.
FIG. 7 is a perspective view showing a schematic configuration of a second embodiment of the optical scanning device according to the present invention. The same elements as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and only different portions are described. The operation of the optical scanning device 1 in the present embodiment is the same as that in the first embodiment, and a description thereof will be omitted.

  In the present embodiment, the first scanning means 2 and the second scanning means 3 are integrally formed on one chip. A specific example of each scanning means 2 and 3 is configured using the first galvanometer mirror 30 and the second galvanometer mirror 30 'shown in FIG. However, in this embodiment, as shown in FIG. 7, the fixing part 31 of each scanning means 2 and 3 is shared. In FIG. 7, the drive coil 35, the electrode terminals 36 and 36, and the permanent magnets 37 and 37 of the scanning units 2 and 3 are not shown for simplification of the drawing.

  8 is a cross-sectional view of the optical scanning device 1 shown in FIG. As can be seen from FIG. 8, also in the present embodiment, for example, a point obtained by projecting the center point 2d of the first light reflecting surface 2a onto the reference plane coincides with one focal point F1 of the ellipse, and the second light reflecting surface 3a A position where a point obtained by projecting the center point 3d on the reference plane coincides with the other focus F2 located between the one focus F1 and the elliptical mirror 4, and the reference plane is located between the center point 2d and the center point 3d. Since the relationship can be satisfied, the light collecting characteristic of the elliptical mirror 4 can be used as in the first embodiment.

According to the optical scanning device 1 according to the present embodiment configured as described above, similarly to the first embodiment, the scanning field angle θ ₂ can be increased without increasing the magnitude of the drive signal. Further, according to the optical scanning device 1 according to the present embodiment, since the scanning means 2 and 3 are integrally formed on one chip, the second scanning means 3 with respect to the first scanning means 2 is assembled at the time of assembly. There is no need to adjust the placement position. Therefore, as compared with the first embodiment in which the first scanning unit 2 and the second scanning unit 3 are formed separately, assembly adjustment can be simplified.

  FIG. 9 is a diagram illustrating a modification of the optical scanning device 1 according to the second embodiment. As shown in FIG. 9, in this modification, the first scanning means 2 has a plurality of first divided movable plates formed by equally dividing the first movable plate 2c in the direction orthogonal to the first swing shaft 2b. 2c ′, each divided first movable plate 2c ′ is formed to have a respective first swing shaft 2b ′, 2b ′, and the second scanning means 3 is orthogonal to the second swing shaft 3b. A plurality of second divided movable plates 3c ′ formed by equally dividing the second movable plate 3c in the direction, and each second divided movable plate 3c ′ has a second swing shaft 2b ′, 2b ′. It is formed.

  With this configuration, the weight of each of the movable movable plates 2c ′ and 3c ′ is lighter than that of each of the movable plates 2c and 3c before the division, so that the resonance frequency of each of the movable movable plates 2c ′ and 3c ′ is high. Become. Therefore, the light can be scanned at high speed by increasing the frequency of the drive signal supplied from the drive means 5 to each of the scanning means 2 and 3.

  In the present modification, the total area of the plurality of first reflecting surfaces 2a ′ is formed to be the same as the area of the first reflecting surface 2a before the division shown in FIG. The total area of the two reflecting surfaces 3a ′ is formed to be the same as the area of the second reflecting surface 3a before the division. As a result, when the optical scanning device 1 is also used as means for receiving reflected light from the target area of the optical distance measuring device, light can be scanned at high speed while the amount of received light is maintained.

  In the first and second embodiments, the case where the optical scanning device 1 is used as the optical scanning unit of the optical distance measuring device has been described. However, the optical scanning device 1 is not limited to this and is a laser scanning type. It can also be used as light scanning means in a projector. Even in this case, since the scanning angle of view can be increased with the same driving signal size as in the prior art, the scanning angle of view can be increased without increasing the size of the driving signal.

DESCRIPTION OF SYMBOLS 1 ... Optical scanning apparatus 2 ... 1st scanning means 2a ... 1st light reflection surface 2b ... 1st rocking | fluctuation shaft 2c ... 1st movable plate 2d ... 1st light Reflection point on reflection surface (center point)
2c ′ ·· the first divided movable plate 3 ··· second scanning means 3a ··· the second light reflecting surface 3b ··· the second swinging shaft 3c ··· the second movable plate 3c '··· the second Dividing movable plate 3d: Reflection point (center point) on the second light reflecting surface
4 ... Elliptical mirror 4a ... Reflecting surface 5 ... Driving means L1 ... Ellipse long axis F1 ... One focus F2 ... Other focus

Claims (3)

A first movable plate having a first light reflecting surface and swingable about a first swing axis is provided. When the first movable plate swings, the light source moves from the light source to the first light reflecting surface. First scanning means for reflecting and scanning incident light;
The light scanning direction of the first scanning means is curved in an arc shape on the long axis side of the ellipse, and the reflecting surface is formed by extending the arc shape in the direction orthogonal to the light scanning direction of the first scanning means. An elliptical mirror that reflects light incident from the first scanning means;
A second movable plate having a second light reflecting surface and swingable about a second swing axis is provided, and the light from the elliptical mirror is transmitted by the second movable plate swinging. Second scanning means for performing reflection scanning in a direction orthogonal to the optical scanning direction of the one scanning means;
Drive means for supplying drive signals for swinging the first and second movable plates about the swing axes to the first and second scanning means, respectively;
With
The first scanning means is arranged so that a point obtained by projecting a reflection point on the first light reflection surface onto the reference plane when viewed from a direction perpendicular to the reference plane including the ellipse coincides with one focal point of the ellipse. A point obtained by projecting a reflection point on the second light reflecting surface onto the reference plane when viewed from a direction perpendicular to the reference plane coincides with the other focus located between the one focal point and the elliptical mirror, and An optical scanning apparatus comprising: the second scanning unit arranged so as to be opposite to the first scanning unit with respect to the reference plane.   The optical scanning device according to claim 1, wherein the first scanning unit and the second scanning unit are integrally formed on one chip.   The first scanning means includes a plurality of first divided movable plates formed by equally dividing the first movable plate in a direction orthogonal to the first swing axis, and each first divided movable plate is respectively A plurality of second divisions formed by equally dividing the second movable plate in a direction orthogonal to the second oscillation axis. 3. The optical scanning device according to claim 1, further comprising a movable plate, wherein each of the second divided movable plates has the second swing shaft.