JP2011169927A - Optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner capable of obtaining a required amplitude, without changing the position of a beam part supporting a mirror part, when a substrate is vibrated. <P>SOLUTION: Substrate rigidity reduction parts 9 for reducing the rigidity of substrate tongue parts 8 are respectively formed, in positions axially symmetric with respect to an axis line M in the longitudinal direction of the substrate in the vicinity of the connection part of the beam part 3, in a pair of substrate tongue parts 8 to which the beam part 3 of the substrate 1 is connected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical scanning apparatus that performs scanning by reflecting a light beam emitted from a light source by a oscillating mirror.

  An optical scanning device that scans a light beam such as a laser beam emitted from a light source is used as an optical device such as a barcode reader, a laser printer, or a head-mounted display, or a light intake device of an imaging device such as an infrared camera.

  For example, in FIGS. 7A and 7B, a pair of substrates on the free end side of a substrate 52 (for example, a stainless steel substrate or a silicon substrate) clamped and supported by a support member 51 and a clamp member 57 in a cantilever manner. A tongue portion 53a is provided on both sides, and a mirror portion 55 having both sides connected by beam portions 54 is provided in an opening 53b formed between the substrate tongue portions 53a. The mirror unit 55 is mirror-finished, has a reflective film formed, or has a mirror attached to the substrate.

  Further, the substrate 52 is provided with a vibration source 56 made of a thin film of a piezoelectric body, a magnetostrictive body, or a permanent magnet. For example, in the case of a piezoelectric body, when a positive voltage is applied from a driving source (not shown), an extension occurs and a negative voltage is generated. Since the shrinkage occurs when the voltage is applied, the substrate 52 is bent. Torsional vibration is generated in the beam portion 54 with respect to the vertical deflection of the substrate 52, and the mirror portion 55 swings.

  The driving frequency is maintained near the resonance frequency between the mirror portion 55 and the beam portion 54, and the laser beam is reflected by the vibrating mirror portion 55 to perform optical scanning. Accordingly, the manufacturing cost is lower than that of an optical scanning device that swings a micro mirror manufactured using MEMS (Micro Electro Mechanical System), and a large vibration is generated in the mirror unit 55 by a small vibration source 56. It has become. Since stress concentration easily occurs in the beam portion 54 during deformation, a slit is formed to reduce the stress concentration (see Patent Documents 1 and 2).

JP 2009-109905 A JP 2007-268374 A

Since the pair of substrate tongues 53a provided at the free ends of the cantilevered substrate 52 described above are designed with an equal width, the substrate tongues at the free ends where the substrate 52 vibrates when the vibration source 56 is operated. The position of the node formed in 53a is difficult to control. If the position of the node does not coincide with the beam portion 54 and shifts up and down, the required scanning accuracy cannot be obtained in combination with the assembly error of the optical scanning device. Further, since the rigidity in the substrate vibration direction is high in the pair of substrate tongue portions 53a, it is difficult to obtain the amplitude necessary for optical scanning.
Therefore, it is necessary to adjust the clamping position of the substrate 52 that is cantilevered so that the position of the beam portion 54 and the position of the node coincide with each other by trial and error.

  It is an object of the present invention to provide an optical scanning device that can obtain a necessary amplitude without changing the position of a beam portion that supports a mirror portion when a substrate is vibrated.

  A mirror part supported on both sides by a beam part is formed in an opening formed on the other end side of the board supported in a cantilever manner on one side in the longitudinal direction, and the vibration source provided on the board is operated. An optical scanning device that scans by deflecting the substrate and deflecting the irradiation light while oscillating the mirror portion with the beam portion as an oscillating axis, wherein the beam portion of the substrate is connected Substrate rigidity lowering portions for reducing the rigidity of the substrate tongue portion are formed on the pair of substrate tongue portions in the vicinity of the connection portion of the beam portion and symmetrical with respect to the longitudinal axis of the substrate. It is characterized by.

  The substrate rigidity decreasing portion is characterized in that any one of a through hole, a dent, and a notch is formed by pressing or etching.

Substrate rigidity lowering portion that reduces the rigidity of the substrate tongue at a position near the connection portion of the beam portion and symmetrical with respect to the longitudinal axis of the substrate to a pair of substrate tongues to which the beam portions of the substrate are connected When each is formed, when the vibration source is operated to vibrate the substrate, the substrate is likely to vibrate with the substrate rigidity lowered portion having low substrate rigidity as a node.
Therefore, since the mirror part is easy to swing with the beam part as a node, the amplitude of the mirror is enlarged and the position of the beam part is difficult to move even with the same substrate size, so that the scanning range is stabilized and the clamp position of the substrate is adjusted. Work can also be simplified.

  Since the substrate rigidity reduction part can be formed by pressing or etching any of the through holes, dents or notches without any effort or man-hours, the stable characteristics of the optical scanning device can be maintained with a simple configuration. it can.

It is the top view and arrow AA sectional drawing of an optical scanning device. It is the top view and arrow AA sectional drawing of the optical scanner which concerns on another example. It is the top view and arrow AA sectional drawing of the optical scanner which concerns on another example. It is the top view and arrow AA sectional drawing of the optical scanner which concerns on another example. It is the top view and arrow AA sectional drawing of the optical scanner which concerns on another example. It is the top view and arrow AA sectional drawing of the optical scanner which concerns on another example. It is the top view and arrow AA sectional drawing of the conventional optical scanning device.

  Embodiments of an optical scanning device according to the present invention will be described below with reference to the drawings. In this embodiment, an optical scanning device (scanner) used for a laser beam printer will be described as an example.

[First embodiment]
A schematic configuration of the optical scanning device will be described with reference to FIGS. 1 (a) and 1 (b).
The substrate 1 is preferably a rectangular substrate such as a metal plate (stainless steel; SUS304) or a silicon substrate (Si). The substrate 1 is sandwiched between a support member 7 and a clamp member 6 on one side in the longitudinal direction and is supported in a cantilever manner.

  A pair of substrate tongues 8 are formed on the other end side (free end side) of the substrate 1. In the opening 2 formed between the substrate tongues 8, a mirror part 4 supported on both sides by the beam part 3 is provided.

  Further, a piezoelectric element (PZT; lead zirconate titanate) is provided as an oscillation source 5 at the center of one end side of the substrate 1 by adhesion or the like. By operating the vibration source 5 to vibrate the substrate 1, scanning is performed by reflecting the irradiation light while swinging the mirror portion 4 with the beam portion 3 as the swing axis.

  In FIG. 1A, the pair of substrate tongues 8 to which the beam portion 3 of the substrate 1 is connected are in the vicinity of the connection portion of the beam portion 3 (on the central axis L in the substrate short direction of the beam portion 3). Square holes 9 (through-holes; substrate rigidity reduction portions) are respectively drilled at positions that are axially symmetric with respect to the axis M in the substrate longitudinal direction. As the hole shape of the square hole 9, rectangular holes such as a square, a rectangle, a parallelogram, and a rhombus are formed. The square holes 9 can be formed by pressing or etching in the substrate manufacturing process.

  Due to the presence of the square holes 9, the rigidity of the substrate tongue 8 in the vibration direction is lowered. For this reason, when the vibration source 5 is operated to vibrate the substrate 1, the substrate 1 is likely to vibrate with the vicinity of the square hole 9 having a low rigidity in the substrate tongue 8 as a node. Therefore, since the mirror part 4 easily swings with the beam part 3 as a node, the amplitude of the mirror part 4 is enlarged and the position of the beam part 3 is difficult to move even with the same substrate size. The adjustment work of the clamp position of 1 can also be simplified.

[Second Embodiment]
Next, another example of the optical scanning device will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is incorporated. In the present embodiment, the positions at which the square holes 9 (substrate rigidity lowering portions) are provided differ from the substrate tongue 8.

The pair of substrate tongues 8 provided on the free end side of the substrate 1 are adjacent to the connection portion of the beam portion 3 (position shifted to the vibration source 5 side from the central axis L of the beam portion 3 in the substrate short direction). Square holes 9 are drilled at positions that are axially symmetric with respect to the axis M in the longitudinal direction of the substrate.
Note that the square hole 9 may be formed at a position shifted to the free end side from the central axis L of the beam portion 3 in the lateral direction of the substrate. This square hole 9 can also be formed by pressing or etching in the substrate manufacturing process.
Also with the above configuration, when the substrate 1 is vibrated, the substrate 1 is likely to vibrate with the beam portion 3 in the vicinity of the square hole 9 having low rigidity in the substrate tongue 8 as a node.

[Third embodiment]
Next, another example of the optical scanning device will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is incorporated.
In this embodiment, the shape of the board rigidity reduction portion provided for the board tongue 8 is different. That is, the pair of substrate tongues 8 provided on the free end side of the substrate 1 has a substrate longitudinal axis M in the vicinity of the connection portion of the beam portion 3 (on the substrate lateral direction central axis L of the beam portion 3). Round holes 10 (through-holes; substrate rigidity reduction portions) are respectively drilled at positions that are axially symmetric. The round hole 10 can also be formed by pressing or etching in the substrate manufacturing process. An elliptical hole or a long hole may be used instead of the round hole 10.
Also with the above configuration, when the substrate 1 is vibrated, the substrate 1 is easily vibrated with the beam portion 3 in the vicinity of the round hole 10 having low rigidity in the substrate tongue portion 8 as a node.

[Fourth embodiment]
Next, another example of the optical scanning device will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is incorporated.
In this embodiment, the shape of the board rigidity reduction portion provided for the board tongue 8 is different. That is, the pair of substrate tongues 8 provided on the free end side of the substrate 1 are notched in the width direction of the substrate tongue 8 adjacent to one side (free end side) of the connection portion of the beam portion 3. In addition, a slit 11 (notch; substrate rigidity reduction portion) is formed. The slits 11 are formed in the substrate tongue 8 at positions that are axially symmetric with respect to the axis M in the substrate longitudinal direction. The slit 11 can also be formed by pressing or etching in the substrate manufacturing process. In addition, although the slit 11 was provided in the inner side edge part which the board | substrate tongue part 8 opposes, you may be provided in the outer side edge part of the board | substrate tongue part 8. FIG.
Also with the above configuration, when the substrate 1 is vibrated, the substrate 1 is likely to vibrate with the beam portion 3 adjacent to the slit 11 having low rigidity in the substrate tongue 8 as a node.

[Fifth embodiment]
Next, another example of the optical scanning device will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is incorporated.
In this embodiment, the arrangement of the board rigidity lowering portion provided for the board tongue 8 is different. In other words, the pair of substrate tongues 8 provided on the free end side of the substrate 1 are adjacent to both sides (vibration source side and free end side) of the connection portion of the beam 3, respectively, in the width direction of the substrate tongue 8. A slit 11 (notch; substrate rigidity reduction portion) is formed. The slits 11 are formed in the substrate tongue 8 at positions that are axially symmetric with respect to the axis M in the substrate longitudinal direction. These slits 11 can also be formed by pressing or etching in the substrate manufacturing process. In addition, although the slit 11 was provided in the inner side edge part which the board | substrate tongue part 8 opposes, you may be provided in the outer side edge part of the board | substrate tongue part 8. FIG.
Also with the above configuration, when the substrate 1 is vibrated, the substrate 1 is likely to vibrate with the beam portion 3 adjacent to the slit 11 having low rigidity in the substrate tongue 8 as a node.

[Sixth embodiment]
Next, another example of the optical scanning device will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is incorporated.
In this embodiment, the shape of the board rigidity reduction portion provided for the board tongue 8 is different. In other words, the pair of substrate tongues 8 provided on the free end side of the substrate 1 has an axis line in the longitudinal direction of the substrate in the vicinity of the connection portion of the beam portion 3 (on the central axis L in the substrate short direction of the beam portion 3). Recesses 12 (substrate rigidity reduction portions) are respectively carved at positions that are axially symmetric with respect to M. The shape of the recess 12 can be formed in any shape such as a rectangle such as a square, a rectangle, a parallelogram, and a diamond, or a circle, an ellipse, and an ellipse. Further, the bottom of the recess 12 may be flat or curved. The recess 12 can be formed by pressing or etching in the substrate manufacturing process.
Also with the above configuration, when the substrate 1 is vibrated, the substrate 1 is likely to vibrate with the beam portion 3 adjacent to the recess 12 having low rigidity in the substrate tongue portion 8 as a node.

  As the vibration source 5, in addition to the piezoelectric element, any one of a piezoelectric body, a magnetostrictive body, and a permanent magnet body may be directly formed in a film shape on the substrate. As a film formation method, for example, an aerosol deposition method (AD method), a vacuum deposition method, a sputtering method, a chemical vapor deposition method (CVD: Chemical Vapor Deposition), or a sol-gel method is used. When any one of the piezoelectric body, the magnetostrictive body, and the permanent magnet body is directly formed in a film shape on the substrate, an optical scanning device that is driven at a low voltage and consumes low power can be provided.

  When a magnetostrictive body or a permanent magnet body is used, an alternating magnetic field applied from the outside generates an alternating magnetic field by passing an alternating current through a coil provided near the substrate portion on which the magnetostrictive film and the permanent magnet film are formed. In addition, when forming on a board | substrate with a magnetostriction film | membrane or a permanent magnet film, the direction where a board | substrate material is a nonmagnetic material can generate | occur | produce bending more efficiently.

  The mirror unit 4 may be a mirror-finished substrate 1 when a metal plate is used for the substrate 1. When a substrate other than a metal plate or a metal plate is required to have higher reflection performance, a thin film is formed on the mirror portion 4 by a thin film forming technique such as vacuum deposition, sputtering, or CVD (chemical vapor deposition). Alternatively, a mirror reflection material may be separately attached to the mirror unit 4.

In addition, the material for forming the thin film is selected from gold (Au), silicon dioxide (SiO ₂ ), aluminum (Al), or magnesium fluoride (MgF ₂ ), or a combination of two or more materials. Furthermore, by controlling the same layer (= single layer) or a multilayer structure of two or more layers by the thin film forming technique to an appropriate film thickness, a thin film that improves reflection performance can be formed. Alternatively, as a material for separately attaching a reflector for mirror to the mirror part 4, a thin film is formed on the mirror-finished silicon (Si) or alumina titanium carbide (Al ₂ O ₃ -TiC) ceramic by the above-mentioned thin film forming technique. May be formed.

  Further, regarding the thickness of the substrate 1, considering the flatness of the mirror part 4 in operation and the mirror size required for application to a projector device, silicon (Si), stainless steel (SUS304, etc.), or the like Further, assuming a substrate in which carbon nanotubes are grown on the material, a thickness of at least 10 μm or more is desirable.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Opening part 3 Beam part 4 Mirror part 5 Vibration source 6 Clamp member 7 Support member 8 Substrate tongue part 9 Square hole 10 Round hole 11 Slit 12 Recess

Claims (2)

A vibration part provided on the substrate, in which a mirror part supported on both sides by a beam part is formed in an opening part formed on the other end side of the substrate supported in a cantilever manner on one side in the longitudinal direction of the rectangular substrate. An optical scanning device that scans by reflecting irradiation light while oscillating the mirror portion with the beam portion as an oscillating axis by actuating a source and bending the substrate,
A substrate in which the rigidity of the substrate tongue is lowered to a pair of substrate tongues to which the beam portion of the substrate is connected, in the vicinity of the connection portion of the beam portion and in an axially symmetrical position with respect to the axis in the longitudinal direction of the substrate An optical scanning device, wherein each of the rigidity reduction portions is formed.   2. The optical scanning device according to claim 1, wherein the substrate rigidity lowering portion is formed by pressing or etching one of a through hole, a dent, and a notch.

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