JPH05241088A - Vibrator and optical scanner - Google Patents

Abstract

PURPOSE:To provide the vibrator and optical scanner which utilize elastic resonant vibration caused by increasing the rotational angle and scanning angle in the bending direction of an elastic deformation part. CONSTITUTION:A vibration input part 3 is provided at one end of the rod-shaped elastic deformation part 2 and a scanning part 4 is provided at the other end to manufacture the vibrator A. When vibration of resonant frequency fB in bending deformation mode is applied from the vibration input part 3, this vibration is transduced into bending deformation by the elastic deformation part 2 to rotate the scanning part 4. The vibrator A is formed of an (100) single crystal silicon substrate and has an (100) plane as its main surface 7 and a [011] direction as the direction of the axis (m) of the elastic deformation part 2. The (100) plane as the main surface 7 of the elastic deformation part 2 and the (111) plane of the single crystal silicon or the intersection 1 with the plane crosses the [011] direction of the elastic deformation part 2 at right angles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrator and an optical scanner. Specifically, the vibrator of the present invention is such that the scanning unit is rotated by the vibration applied to the vibration input unit. Further, the optical scanner of the present invention is configured to scan a light beam by using the vibrator, and for example, a one-dimensional or two-dimensional scanning of the light beam in a laser beam printer, a bar code reader or the like. is there.

[0002]

2. Description of the Related Art In recent years, various optical components have been reduced in size and weight, and optical devices such as laser beam printers and bar code readers have also been required to be reduced in size and weight. However, in an optical device such as a laser beam printer, miniaturization of a light beam scanning mechanism for scanning a light beam is a bottleneck.

At present, a polygon scanner using a polygon mirror is used as a light beam scanning mechanism of these optical devices. FIG. 4 shows a conventional polygon scanner G having a structure in which a regular polygonal columnar polygon mirror 22 having a mirror surface 21 formed on each outer peripheral surface is driven and rotated by a DC servo motor 23.
That is, when the light beam α emitted from the light emitting element 24 is applied to the mirror surface 21 of the polygon mirror 22, the light beam α is reflected by the mirror surface 21 of the polygon mirror 22, and the light beam α reflected by the mirror surface 21. The emission direction of the beam changes with the rotation of the polygon mirror 22, and the light beam α is scanned.

However, since such a polygon scanner G is composed of the polygon mirror 22 and the DC servomotor 23, it is difficult to miniaturize and the cost is high.

Therefore, the applicant of the present invention has proposed a vibrator utilizing elastic resonance vibration of a spring (elastic deformation portion) and a microminiature optical scanner using this vibrator (embodiment of FIG. 1). See). This vibrator is one in which a vibration input section is provided at one end of a rod-shaped elastically deformable section having spring properties, and a scan section is provided at the other end. For example, when the vibration input section is vibrated by a drive source such as a piezoelectric element. The elastic deformation section resonates to convert the vibration of the vibration input section into the rotational movement of the scanning section and rotate the scanning section. Therefore, if a drive source is provided in this vibration input section and a mirror surface is formed in the scan section, when the light beam emitted from the light emitting element is applied to the mirror surface, the light beam is scanned by the rotation of the scan section. To be done.

The performance of such an optical scanner is determined by the material of the vibrator and the processing accuracy of the elastically deformable portion. For this reason, the inventors of the present invention initially manufactured a vibrator made of stainless steel by mechanical processing and manufactured an optical scanner using the vibrator made of stainless steel. It was difficult to obtain sufficient processing accuracy due to the occurrence of distortion and burrs, and it was not possible to obtain satisfactory performance.

Therefore, the inventors of the present invention have tried to obtain a vibrator having a predetermined shape by using a semiconductor substrate such as a single crystal silicon substrate and anisotropically etching the semiconductor substrate. Initially, a (110) silicon substrate was used to fabricate a vibrator such that the principal surface of the vibrator was the (110) plane and the side surface of the elastically deformable part was the {111} plane. The cross-sectional shape of the elastically deformable portion of the vibrator thus manufactured was rectangular, and a vibrator having a shape substantially equivalent to that of the stainless vibrator could be obtained.

However, in the vibrator manufactured by using such a crystal orientation, the bending of the elastically deforming portion when the vibrator is resonated in the bending deformation mode is small, and the scan when the resonator is resonated in the bending deformation mode is generated. There is a drawback in that the rotation angle of the portion (hereinafter referred to as the bending angle in the bending direction) cannot be made sufficiently large. Therefore, in a vibrator or an optical scanner that can be driven in two modes, a bending deformation mode and a twisting deformation mode, the rotation angle of the scanning unit when resonating in the twisting deformation mode (hereinafter, rotation in the twisting direction). The angle of rotation in the bending direction is smaller than that of the angle), and the scanning state becomes unbalanced.

Further, the (110) silicon substrate has a drawback that the unit cost of a wafer is high and the cost of the vibrator or the optical scanner is high.

The present invention has been made in view of the above background art, and an object of the present invention is to provide a vibrator made of single crystal silicon utilizing elastic resonance vibration of a spring (elastically deformable portion) and the vibration. In a microminiature optical scanner using a child, it is to increase the rotation angle and the scanning angle of the elastically deformable portion in the bending direction.

[0011]

A vibrator of the present invention includes an elastic deformation portion having at least one elastic deformation mode, a vibration input portion provided at one end of the elastic deformation portion, and an elastic deformation portion at the other end of the elastic deformation portion. A vibrator having a scanning unit provided, wherein the vibration applied to the vibration input unit is converted into a predetermined elastic deformation mode by the elastic deformation unit to rotate the scanning unit in at least one direction. , Monocrystalline silicon, and a line of intersection between the {111} plane of the monocrystalline silicon and the main surface of the elastically deformable portion is orthogonal to the axis of the elastically deformable portion.

Further, the optical scanner according to the present invention has an elastically deformable portion having at least one elastically deformable mode, a vibration input portion provided at one end of the elastically deformable portion, and a scan provided at the other end of the elastically deformable portion. And a vibrator configured to rotate the scan unit in at least one direction by converting the vibration applied to the vibration input unit into a predetermined elastic deformation mode by the elastic deformation unit, and the elastic deformation unit. An optical scanner comprising a drive source for applying a vibration of a resonance frequency for an elastic deformation mode to a vibration input section and a mirror surface provided in the scanning section, wherein the vibrator is made of single crystal silicon. The line of intersection between the {111} plane of single crystal silicon and the main surface of the elastically deformable portion is orthogonal to the axis of the elastically deformable portion.

[0013]

In the vibrator of the present invention, the {111} plane of single crystal silicon, for example,

[Outer 1] A line of intersection between any one of these planes and the main surface of the elastically deformable portion is orthogonal to the axis of the elastically deformable portion. Further, it is known that in a silicon single crystal, a crystal slip is likely to occur on the {111} plane. Therefore, when the vibrator is vibrated in the bending deformation mode, the bending of the elastic deformation portion becomes large due to the occurrence of the {111} plane slip in the elastic deformation portion,
It is possible to increase the rotation angle of the scan portion in the bending direction as compared with the conventional vibrator made of single crystal silicon.

Further, in the case of a vibrator driven by the bending deformation mode and the twisting deformation mode, the turning angle in the bending direction is increased by increasing the turning angle in the bending direction. Therefore, the rotation angles in the two directions can be balanced.

Further, since the oscillator having such a crystal orientation can be manufactured by using a substrate other than the (110) silicon substrate, a single crystal silicon substrate having a low unit price per one, for example, A vibrator can be obtained by using a (111) silicon substrate by a dry etching process or the like, whereby a low-cost vibrator can be manufactured.

Similarly, in the optical scanner of the present invention,
It is possible to increase the scanning angle of the light beam when the vibrator is vibrated in the bending deformation mode. Further, in the case of the optical scanner driven in the bending deformation mode and the twisting deformation mode, the scanning angle of the light beam in the bending direction can be increased, and the scanning angle in the bending direction and the scanning angle in the twisting direction can be balanced.

Further, the cost of the optical scanner can be reduced by using such a vibrator.

[0018]

1 is a block diagram of an optical scanner B according to an embodiment of the present invention.
It is a perspective view showing. The optical scanner B includes a vibrator A formed of single crystal silicon in a plate shape, and a driving source 1 such as a piezoelectric vibrator or a magnetostrictive vibrator. The vibrator A made of single crystal silicon includes a shaft rod-shaped elastically deformable portion 2, a vibration input portion 3 to which a vibration is applied from a driving source 1, and a scan portion 4 which is rotated by elastic vibration of the elastically deformable portion 2. The vibration input section 3 is provided at one end of the elastic deformation section 2, and the scanning section 4 is provided at the other end. Here, the elastic deformation portion 2 is along a torsional deformation mode in which it is torsionally deformed around the axis P and the axis P (that is, around an axial direction parallel to the Q axis orthogonal to the axis P).
A bending deformation mode of bending deformation is possible, and has a resonance frequency of f _T for elastic vibration of the torsion deformation mode and a resonance frequency of f _B for elastic vibration of the bending deformation mode. The scanning part 4 is formed in an unbalanced shape with respect to the axis P of the elastically deforming part 2, and a weight part 5 for biasing the center of gravity to a position away from the axis P of the elastically deforming part 2 is formed. .. Therefore, the center of the scanning section 4 is located off the axis P of the elastically deforming section 2, and is located above the upper end of the elastically deforming section 2. Further, a mirror surface 6 for reflecting the light beam α is formed on the scanning section 4. This mirror surface 6
May be formed on the entire scanning unit 4, or may be partially provided in the vicinity of the axis P. The vibration input unit 3 is fixed to the drive source 1 by being adhered or joined thereto, and the scanning unit 4 is supported by the elastic deformation unit 2 freely.

The drive source 1 for transmitting high-frequency vibrations to the vibration input section 3 is controlled by a scanner drive circuit (not shown), and has a frequency equal to the resonance frequency f _T of the twist deformation mode from the scanner drive circuit to the drive source 1. When the drive signal (AC voltage) is applied, the drive source 1 vibrates at a frequency of f _T and transmits the vibration to the vibration input unit 3. When the frequency f _T in the torsional deformation mode is applied to the vibration input unit 3, the elastically deforming unit 2 is torsionally deformed by resonance, and the scanning unit 4 rotates around the P axis at a cycle of 1 / f _T and a rotation angle θ _T. Move.

Similarly, when a drive signal having a frequency equal to the resonance frequency f _B of the bending deformation mode is applied from the scanner drive circuit to the drive source 1, the drive source 1 vibrates at the frequency of f _B ,
The vibration is transmitted to the vibration input unit 3. When the frequency f _B of the bending deformation mode is applied to the vibration input unit 3, the elastic deformation unit 2 bends and deforms due to resonance, and the scanning unit 4 rotates around the Q direction at a cycle of 1 / f _B and a rotation angle θ _B. Move. The rotation angles θ _T and θ _B of the scan unit 4 can be adjusted by the magnitude of the voltage applied to the scanner drive circuit.

FIG. 2 is a partially cutaway perspective view showing the crystal orientation of a vibrator A manufactured from a single crystal silicon substrate.
This oscillator A is manufactured from a (100) single crystal silicon substrate, and the principal surface 7 of the oscillator A becomes the (100) face,
The elastic deformation portion 2 is manufactured by a dry etching process so that the direction of the axis m is the [011] direction.
Moreover, the line of intersection l between the (100) plane which is the main surface 7 of the elastically deformable portion 2 and the (111) plane or the 111b plane of single crystal silicon.
Is

[Outside 2] And is orthogonal to the direction [011] of the axis m of the elastically deformable portion 2. Further, the elastically deformable portion 2 has a trapezoidal cross section, and the side surface 8 is a 111c surface. The mirror surface 6 having a mirror surface shape is directly formed on the surface of the scan unit 4 by etching.

Thus, the {11
When the direction of the line 1 of intersection between the 1} plane and the principal surface of the elastically deformable portion 2 is orthogonal to the direction of the axis m of the elastically deformable portion 2, the normal direction of the {111} plane in which the crystal is likely to slip is , A direction normal to the axis m of the elastically deformable portion 2 and the main surface [in the embodiment shown in FIG.
The surface including the [0] direction] [the elastically deformable portion 2 is bent and deformed in this surface]. ], When the elastically deformable portion 2 is bent and deformed, slippage of the {111} plane occurs in the elastically deformable portion 2 and a large bend occurs. As a result, when the vibrator A is vibrated in the bending deformation mode, the rotation angle θ _B of the scan section 4 in the bending direction can be increased due to the slip of the {111} plane.

In this vibrator A, since the side surface of the elastically deformable portion 2 is the 111c surface, the rotational angle θ _{T of the} elastically deformable portion 2 in the torsional direction is driven when driven in the torsional deformation mode. Although it is expected to decrease, this drawback can be overcome by appropriately narrowing the width of the elastic deformation portion 2, and the rotation angle θ _T when driven in the torsion deformation mode is equivalent to that of the conventional vibrator A. Can be Further, in the above description, the oscillator A manufactured using the (100) single crystal silicon substrate has been described, but the single crystal silicon substrate as a starting material may have a crystal orientation other than this.
For example, a similar oscillator can be formed by a dry etching process using a (111) single crystal silicon substrate.

FIG. 3 is a partially cutaway perspective view showing a light beam scanning light source C using the optical scanner B. Case 9
A light projector 10 equipped with a light emitting element such as a light emitting diode or a semiconductor laser element is provided on the inner wall surface of the light projector 1.
The optical scanner B is installed between 0 and the light beam scanning window 11 provided in the case 9.

Thus, the light beam emitted from the projector 10 (collimated light or focused light close to collimated light)
When α is applied to the mirror surface 6 of the optical scanner B, the light beam α is reflected by the mirror surface 6 and emitted from the light beam scanning window 11 to the outside. At this time, when the scanning unit 4 is rotated at the rotation angle of θ _{T in} the twist deformation mode, the light beam α reflected by the mirror surface 6 is scanned at the scanning angle of 2 θ _T. In addition, depending on the bending deformation mode, the scanning unit 4 may
_When rotating at the rotation angle of _B , the light beam α reflected by the mirror surface 6 is scanned at the scanning angle of 2θ _B. In the conventional optical scanner, the scanning angle 2θ _B in the bending direction could not be increased, but in the vibrator A of the present invention, the rotation angle θ _B in the bending direction can be increased, so scanning in the twisting direction is possible. The angle 2θ _T and the scanning angle 2θ _B in the bending direction can be made to have the same magnitude.

In the above embodiment, the oscillator capable of the bending deformation mode and the torsional deformation mode has been described, but an oscillator having only the bending deformation mode may be used, or three oscillators including the bending vibration mode may be used. A vibrator having the above elastic deformation mode may be used.

[0027]

According to the present invention, it is possible to increase the rotation angle of the scan portion in the bending direction as compared with the conventional vibrator made of single crystal silicon. Therefore, for example, in the case of a vibrator driven by the bending deformation mode and the twisting deformation mode, the turning angle in the bending direction is increased by increasing the turning angle in the bending direction. Since the size is increased, the rotation angles in the two directions can be balanced.

Similarly, in the optical scanner of the present invention,
Light beam α when the oscillator is vibrated in bending deformation mode
The scanning angle of can be increased. Further, in the case of the optical scanner driven in the bending deformation mode and the twisting deformation mode, the scanning angle of the light beam in the bending direction can be increased, and the scanning angle in the bending direction and the scanning angle in the twisting direction can be balanced.

Further, in such a vibrator and optical scanner, a single crystal silicon substrate whose unit price is low,
For example, by using a (111) silicon substrate, a vibrator can be obtained by a dry etching process or the like, whereby a low-cost vibrator and optical scanner can be manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view showing an optical scanner according to an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing a crystal orientation of an oscillator made of single crystal silicon of the above.

FIG. 3 is a partially cutaway perspective view showing a light beam scanning light source using the above optical scanner.

FIG. 4 is a perspective view showing a conventional polygon scanner.

[Explanation of symbols]

 A oscillator B optical scanner 1 drive source 2 elastic deformation part 3 vibration input part 4 scan part 6 mirror surface

Claims (2)

[Claims] 1. An elastic deformation part having at least one elastic deformation mode, a vibration input part provided at one end of the elastic deformation part, and a scan part provided at the other end of the elastic deformation part, The vibration applied to the input unit is converted into a predetermined elastic deformation mode by the elastic deformation unit so that the scanning unit has at least 1
A vibrator adapted to rotate in a single direction, which is made of single crystal silicon and has a single crystal silicon {111}
A vibrator, wherein a line of intersection between a surface and a main surface of the elastically deformable portion is orthogonal to an axis of the elastically deformable portion. 2. An elastic deformation part having at least one elastic deformation mode, a vibration input part provided at one end of the elastic deformation part, and a scan part provided at the other end of the elastic deformation part, The vibration applied to the input unit is converted into a predetermined elastic deformation mode by the elastic deformation unit so that the scanning unit has at least 1
And a drive surface for applying vibration of a resonance frequency for the elastic deformation mode of the elastic deformation section to the vibration input section, and a mirror surface provided in the scanning section. The optical scanner, wherein the vibrator is made of single crystal silicon, and a line of intersection between the {111} plane of the single crystal silicon and the main surface of the elastically deformable portion is orthogonal to the axis of the elastically deformable portion. An optical scanner characterized by.