Optical scanner

• US 5,444,565 A
• Filed: 06/11/1993
• Issued: 08/22/1995
• Est. Priority Date: 08/07/1990
• Status: Expired due to Fees

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Goto, Hiroshi
• Primary Examiner(s): Ben, Loha
• Assistant Examiner(s): Phan, James
• Application Number:
  US08/075,292
• Time in Patent Office: 802 Days
• Field of Search: 359/196-202, 359/212-214, 359/221, 359/223, 359/224, 310/36-38, 310/320, 310/321, 310/323, 318/807, 318/808, 348/203, 348/205, 358/474, 358/296, 358/302, 346/108, 346/109, 346/160
• US Class Current: 359/224.1
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors

Abstract

An optical scanner and beam printer using the optical scanner are disclosed in which the optical scanner includes a scanning element supporting a mirror surface, a support element for freely supporting at one end the scanning element and at another end a vibrating element, and a drive source for inducing vibrations in the vibrating element. The support element may be a shaft having two modes of elastic deformation upon vibration or a torsional spring which undergoes deformation upon vibration. Vibrations received by the vibrating element are applied to the scanning element by the support element to cause optical scanning movement by the scanning element.

Claims

1. An optical device for creating an image on a medium comprising:

an optical light source providing a writing light beam;

a medium for receiving said writing light beam to create an image; and

an optical scanner for causing said writing light beam from said light source to be scanned on said medium, said optical scanner comprising;

a scanning element;

a support element for freely supporting at one end thereof said scanning element, said support element being a flexure element;

a vibrating element provided on another end of said support element; and

a drive source for inducing oscillation in said vibrating element, whereby vibration of said vibrating element produces deformation of said support element and consequent scanning movement of said scanning element,

wherein said support element is a shaft having at least two modes of elastic deformation and said drive source induces oscillations in said vibrating element of a resonant frequency corresponding to each mode of elastic deformation of said shaft, said scanning element being rotated in at least two directions by the elastic vibrations of said shaft, and

wherein said vibrating element, shaft and scanning element are integrally formed as a flat plate-like member.

2. An optical device as in claim 1, wherein said drive source comprises means for generating a plurality of oscillating frequencies, means for selecting at least one of said frequencies, and an actuator connected to receive the selected frequencies for vibrating said vibrating element at said selected frequencies.

3. An optical device as in claim 2, wherein said drive source further comprises means for altering the amplitude of the selected frequencies.

4. An optical device as in claim 1, wherein said scanning element includes a weight to provide said scanning element with an imbalance with respect to a center of balance of said deformable shaft.

5. An optical device as in claim 1, wherein said at least two modes of elastic deformation include a twisting mode about said shaft axis and a bending mode in which said shaft bends lengthwise along its axis.

6. An optical device as in claim 5, wherein said drive source comprises

a first oscillator which outputs a signal of a first frequency substantially equal to a resonant frequency of said twisting mode;

a second oscillator which outputs a signal of a second frequency substantially equal to a resonant frequency of said bending mode;

means for amplifying the output of said first and second oscillators;

means for selecting at least one amplified output of at least one of said oscillators; and

an actuator for receiving the at least one amplified output from the selecting means, said actuator vibrating said vibrating element.

7. An optical device as in claim 6, wherein said actuator is selected from the group consisting of a piezoelectric element, an electrostatic element, and a magnetostrictive element.

8. An optical device as in claim 7, wherein said selecting means is capable of selecting amplified outputs from both of said oscillators which are applied to said actuator.

9. An optical device as in claim 6, wherein said amplifying means is a variable gain amplifying means.

10. An optical device as in claim 5, wherein said drive source comprises:

a voltage setting unit for setting a voltage to select a desired vibration frequency, said desired vibration frequency being one which is substantially equal to at least one of a resonant frequency of said twisting mode and a resonant frequency of said bending mode;

a voltage to frequency converter connected to an output of said voltage setting unit;

an amplifier connected to an output of said converter; and

,

an actuator connected to an output of said amplifier, said actuator vibrating said vibrating element.

11. An optical device as in claim 10, wherein said amplifier is a variable gain amplifier.

12. An optical device as in claim 1, wherein said flat plate-like member is a thin plate formed from at least one of a silicon and a glass wafer.

13. An optical device as in claim 12, wherein said thin plate is etched to provide a mirror surface as the scanning element.

14. An optical device as in claim 1, wherein said drive source includes, as an actuator for inducing vibrations in said vibrating element, at least one of a piezoelectric element, an electrostatic element and a magnetostrictive element.