JP2003344797A - Optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and easily reduce the aberration of a scanning locus and to realize very accurate measurement. <P>SOLUTION: A resonant type galvano scanner 11 holding a mirror 12 and having a rotary shaft 111 almost on the mirror plane of the mirror 12 is supported by a galvano scanner 10 having a rotary shaft 101 nearly perpendicularly crossing with the rotary shaft 111, and is provided on a plane obtained by rotating the mirror plane of the mirror 12 around the rotary shaft of the scanner 11 by about 45° with respect to a plane consisting of the rotary shaft 111 of the scanner 11 and the rotary shaft 101 of the scanner 10 in the center of scanning. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device for deflecting and scanning a light beam such as a laser beam.

[0002]

2. Description of the Related Art Generally, a laser microscope, a laser beam printer, a bar code scanner and the like are equipped with an optical scanning device for deflecting and scanning a light beam. A polygon mirror, a galvanometer mirror, etc. are known as an optical scanning device for deflecting and scanning this light beam using an optical mirror.

Such an optical scanning device reciprocally scans a light beam such as a laser beam in one direction on a straight line or in both directions. Therefore, when it is necessary to scan this light beam two-dimensionally, two optical scanning devices are combined and arranged,
A method such as scanning in a raster system is adopted.

However, in the above method, since the two optical scanning devices are provided, the entire device becomes large and
Since it is necessary to dispose a condenser lens between the optical scanning devices of the table, the configuration becomes complicated. Therefore, a structure has been proposed in which one optical scanning device enables two-dimensional scanning.

For example, there is one disclosed in Japanese Patent Application Laid-Open No. 6-337952 and one disclosed in Japanese Patent Application Laid-Open No. 9-54246.

In the former case, as shown in FIG. 6, the mirror portion 4 of the vibrator 3 is rotated on the upper surface of the scanner main body holding base 1 by the vibration of the piezoelectric element 2 in two directions orthogonal to each other, and the mirror portion 4 is rotated. A configuration is disclosed in which the scanner main body 5 that scans the light beam L reflected by the two-dimensionally is mounted.

In the latter case, the rotary block 7 is supported by the rotary drive unit 6 such as a pulse step motor as shown in FIG. In this rotation block 7, the lower end of a movable plate 7a that can be bent and deformed is fixed to a fixed plate 7b, a permanent magnet 7c is attached to the back surface of the movable plate 7a, and a coil 7d is provided on the fixed plate 7b. .

A light reflecting surface 8 is formed on the front surface of the movable plate 7a. The movable plate 7a can be rotated in two directions by rotating the rotating block 7 or exciting the coil 7d by the rotation drive unit 6, and the movable plate 7a can be stopped at an arbitrary angle. The rotation angle by the rotation drive unit 6 is detected by the rotation drive angle detecting means 6a such as a rotary encoder, and the rotation angle in the bending direction of the movable plate 7a is detected by the bending angle detecting means 6b. To be done.

By the way, in the above-mentioned optical scanning device, the mirror A is rotatably arranged around the X and Y axes as shown in FIG. 8, and the incident light B is reflected by the mirror A at the same time. , Is deflected and is configured to scan two-dimensionally as represented by the LM plane in the drawing. Here, the incident light B passes on the XZ plane, and the incident angle with respect to the mirror A is ρ,
The optical axis direction of the emitted light C when the mirror A is at the scanning center is the N axis, and the LM plane is taken as a plane perpendicular to the N axis.

Here, the M axis is parallel to the Y axis, and the mirror A
The rotation angles around the X axis and the Y axis of are respectively φ and θ,
When the direction of the outgoing light C in the LMN space is represented by a unit vector,

[Equation 1] Becomes

Based on this equation, the outgoing light C is given when the incident angle ρ of the incoming light B is 0 °, 30 °, 45 °, and given predetermined rotation angles θ, φ to the mirror A. A locus of the scanning range is projected on the LM plane according to the angle as shown in FIGS. 9 to 11. Thus, the incident angle ρ of the incident light B
Has a characteristic that the rectangle of the scanning locus collapses and the aberration increases.

By the way, when an optical scanning device is used,
Due to the design, if the incident angle ρ is set to 45 degrees, an easy design is possible, but on the other hand, in order to save space, even if the incident angle ρ is made small, it is rarely set to 30 degrees or less. is there. For this reason, the above-mentioned optical scanning device may cause a large measurement error, and is not suitable for a usage pattern in which highly accurate measurement is required.

Further, for the sake of convenience of the drawing, in FIG. 8, the incident optical axis is defined as the XY rotation axis center, and the mirror plane is described on the XY plane.
The arrangement is such that the center of the Y rotation axis and the mirror plane are different.
Therefore, when the incident angle ρ is increased, the aberration of the scanning locus is further increased, and the measurement accuracy is deteriorated.

[0014]

As described above, the conventional optical scanning device has a problem that when the incident angle becomes large, the aberration of the scanning locus becomes large and the measurement accuracy is lowered.

The present invention has been made in view of the above circumstances, and provides an optical scanning device which realizes highly accurate measurement by simply and easily reducing the aberration of the scanning locus. The purpose is to

[0016]

According to the present invention, there is provided an optical scanning device having a mirror portion for reflecting light and capable of deflecting light in at least two directions with respect to an incident optical axis, the mirror portion being held, A first scanning mechanism having a rotation axis on a substantially mirror plane of the mirror section, and a rotation axis which holds the first scanning mechanism and which is substantially perpendicular to and intersects with the rotation axis of the first scanning mechanism. And a second scanning mechanism section, the mirror plane of the mirror section at the center of scanning with respect to the plane formed by the rotation axes of the first and second scanning mechanisms. It was configured by being provided on a plane rotated about 45 degrees around the rotation axis.

According to the above construction, the mirror portion is rotatable about the rotation axes substantially orthogonal to each other via the first and second scanning mechanisms, and when the incident light is guided, it is reflected and deflected, Scan in two dimensions represented by the desired LM plane.

Further, according to the present invention, the incident optical axis is arranged so as to substantially coincide with the rotation axis of the second scanning mechanism.

According to the above structure, the optical axis direction of the emitted light when the mirror portion is at the scanning center is the N axis, the plane perpendicular to the N axis is the LM plane, and the N axis and the Y axis are the same. When the rotation angles of the mirror part around the X axis and the Y axis are φ and θ, respectively, and the direction of the outgoing light in the LMN space is expressed by a unit vector, (L, M, N) = (sin (2θ ), Sin (φ) ・ cos (2
θ), cos (φ) · cos (2θ)), and it becomes possible to minimize the aberration of the locus of the scanning range projected on the LM plane. Therefore, highly accurate two-dimensional scanning can be performed, the layout design is easy, and highly accurate measurement can be realized.

Further, according to this, even if the incident angle becomes large, the aberration of the scanning locus can be set to be as small as possible, and the simplification of the arrangement structure is ensured.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an optical scanning device according to an embodiment of the present invention. For example, for scanning around the X-axis, a galvano scanner 10 constituting a second scanning mechanism is arranged, and the Y-axis is arranged. The resonance type galvano scanner 11 that constitutes the first scanning mechanism is arranged for scanning the surroundings.

That is, the galvano scanner 10 is
The rotary shaft 101 is arranged corresponding to the X axis, and the resonance type galvano scanner 11 is assembled and held on the rotary shaft. In this resonance type galvano scanner 11,
The mirror 12 that constitutes the mirror section is held, and its rotation axis 111 corresponds to the Y axis that is substantially orthogonal to and intersects the X axis.

The mirror 12 has a mirror plane that forms, for example, approximately 45 degrees with respect to the rotation axis 101 of the galvano scanner 10 as shown in FIG. And the center of rotation of the Galvanoscanner 10 are assembled on the surface so as to intersect with each other. In other words, the mirror plane of the mirror 12 is set on a plane rotated by about 45 degrees around the rotation axis of the resonance type galvano scanner 11 with respect to the plane consisting of the X axis and the Y axis.

The incident light D, which is a light beam, is adjusted so as to pass on the rotating shaft 101 of the galvanoscanner 10 and is first reflected by the mirror 12. The emitted light E reflected by the mirror 12 is generated by rotating the rotary shaft 101 of the galvano scanner 10 around the X axis as shown in FIG.
(B) Scanning is performed in the direction of the middle arrow. Then, when the rotary shaft 111 of the resonance type galvano scanner 11 is rotated around the Y axis, the emitted light E reflected by the mirror 12 is scanned in the arrow direction in FIG.

Here, the resonance type galvano scanner 11 is used.
Will be described. That is, as shown in FIG. 3, the resonant galvanometer scanner 11 is assembled by adhering a movable plate 112, a torsion bar 113, and a support frame 114, which are integrally processed from a single crystal silicon substrate by etching, to a metal base 115. The mirror 12 is arranged on one surface of the movable plate 112, and a movable coil including two driving coils 116 for driving the scanner and a detection coil 117 for monitoring the vibration state is formed on the other surface. There is. A magnetic circuit (permanent magnet 118 and magnetic yoke 119) is combined with this movable coil.

The magnetic circuit is substantially parallel to the movable plate 112 and substantially perpendicular to the extending direction of the torsion bar 113 (X direction).
Generates a magnetic field. When a current is passed through the drive coil 116, driving forces having different directions in the Z direction are generated on the two sides parallel to the torsion bar 113 according to Fleming's left-hand rule, and torque is applied to the movable plate 7. The movable plate 7 is swung due to the relationship between the torque and the reaction force of the torsion bar 113, and the incident light D incident on the mirror 12 is reflected and emitted light E is scanned in a desired direction.

In the above structure, when the galvano scanner 10 is rotationally driven around the X axis in synchronization with the scanning frequency of the resonance type galvano scanner 11, the incident light D incident on the mirror 12 is reflected and deflected. Emitted to the LM plane. The emitted light from the mirror 12 is the emitted light E when the mirror 12 is at the scanning center as shown in FIG.
The optical axis direction of is the N axis, and the plane almost perpendicular to it is the LM
The plane is set and the N axis and the Y axis are set substantially parallel to each other.

Here, assuming that the rotation angles of the mirror 12 around the X axis and the Y axis are φ and θ, respectively, the direction in the LMN space is represented by a unit vector, (L, M, N) = (sin ( 2θ), sin (φ) ・ cos (2θ), cos (φ) ・ cos (2
θ)).

When the emitted light E is given a predetermined rotation angle θ or φ to the mirror 12 based on this equation, the locus of the scanning range as shown in FIG. 4 is projected on the LM plane. Therefore,
By scanning the galvano scanner 10 along the scanning locus shown in FIG. 4 in synchronization with the scanning frequency of the resonant galvano scanner 11, the light beam is raster-scanned as shown in FIG. 5, for example. As a result, a two-dimensional optical scanning configuration with almost no aberration of the scanning locus is constructed, and measurement can be performed with high accuracy.

As described above, the optical scanning device includes the mirror 1
2 and holds the rotary shaft 1 on the substantially mirror plane of the mirror 12.
A resonance type galvano scanner 11 having 11 is supported by a galvano scanner 10 having a rotation axis 101 which is substantially perpendicular to and intersects with a rotation axis 111 of the resonance type galvano scanner 11, and at the scanning center, the mirror plane of the mirror 12 is moved to The rotary shaft 111 of the scanner 11 and the rotary shaft 101 of the galvano scanner 10 are arranged on a plane rotated about 45 degrees around the rotary shaft of the resonant galvano scanner 11.

According to this, the resonance type galvano scanner 1
Rotating shaft 111 of No. 1 and rotating shaft 1 of Galvano scanner 10
The locus of the scanning range projected on the LM plane when the rotation angles θ and φ are given to 01 can be set smaller than the aberration of the scanning locus of the conventional optical scanning device as shown in FIG. Becomes As a result, it becomes possible to realize high-precision two-dimensional scanning simply and easily, and also to realize easy design and manufacture, and also to realize desired measurement accuracy that can be used for measurement purposes. .

In the above embodiment, the case where the mirror 12 is arranged in the resonance type galvano scanner 11 and the resonance type galvano scanner 11 is assembled and arranged in the galvano scanner 10 has been described. Without limitation, it is also possible to configure both with a resonance type galvano scanner.

Therefore, the present invention is not limited to the above-described embodiment, and in addition, various modifications can be carried out at the stage of carrying out the invention without departing from the spirit thereof. Further, the embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problem described in the section of the problem to be solved by the invention can be solved, and the effect described in the effect of the invention can be obtained. When the above is obtained, the configuration in which this constituent element is deleted can be extracted as the invention.

[0036]

As described above in detail, according to the present invention, an optical scanning device which realizes highly accurate measurement by being able to easily and easily reduce the aberration of the scanning locus is provided. can do.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an arrangement configuration of an optical scanning device according to an embodiment of the present invention.

FIG. 2 is an arrangement explanatory view schematically showing an arrangement configuration of mirrors in FIG.

3 is a configuration diagram showing the resonance type galvano scanner of FIG. 1. FIG.

FIG. 4 is a diagram showing a locus of a scanning range projected in FIG.

FIG. 5 is a diagram showing a projection trajectory of a raster scan.

FIG. 6 is a configuration diagram showing a conventional optical scanning device.

FIG. 7 is a configuration diagram showing another example of a conventional optical scanning device.

FIG. 8 is a layout explanatory view shown for explaining problems in the layout configuration of the mirrors of FIGS. 6 and 7;

9 is a diagram showing a locus of a scanning range projected when the incident angle is 0 degree according to FIGS. 6 and 7. FIG.

10 is a diagram showing a locus of a scanning range projected when the incident angle is 30 degrees according to FIGS. 6 and 7. FIG.

11 is a diagram showing a locus of a scanning range projected when the incident angle is 45 degrees according to FIGS. 6 and 7. FIG.

[Explanation of symbols]

10 ... Galvano Scanner 101 ... Rotation axis 11 ... Resonant Galvano Scanner 111 ... Rotation axis 112 ... Movable plate 113 ... torsion bar 114 ... Detection coil 115 ... Metal base 116… Drive coil 117 ... Detection coil 118 ... Permanent magnet 119 ... Magnetic yoke 12 ... Mirror D… Incident light E ... Emitted light

Continued front page    (72) Inventor Hiroshi Miyajima             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. F-term (reference) 2C362 BA18 BA83                 2H045 AB13 AB16 AB38 BA12 CA93                 5C072 AA03 BA02 BA04 HA02 HA11                       HB15

Claims (3)

[Claims] 1. An optical scanning device having a mirror portion for reflecting light, capable of deflecting light in at least two directions with respect to an incident optical axis, wherein the mirror portion is held, and the mirror portion is on a substantially mirror plane. A first scanning mechanism having a rotation axis on its inner side; and a second scanning mechanism section having the rotation axis which holds the first scanning mechanism and which is substantially perpendicular to and intersects the rotation axis of the first scanning mechanism. At the center of scanning, the mirror plane of the mirror unit is about 45 degrees around the rotation axis of the first scanning mechanism with respect to the plane formed by the rotation axes of the first and second scanning mechanisms. An optical scanning device provided on a rotated plane. 2. The optical scanning device according to claim 1, wherein the incident optical axis is arranged so as to substantially coincide with a rotation axis of the second scanning mechanism. 3. The optical scanning device according to claim 1, wherein at least one of the first and second scanning mechanisms is formed by a resonant galvano scanner.