Optical device, method for controlling optical device, and image display apparatus

Patent metadata

Field	Value
Publication number	US-2020371402-A1
Application number	US-202016881070-A
Country	US
Kind code	A1
Filing date	May 22, 2020
Priority date	May 23, 2019
Publication date	Nov 26, 2020
Grant date	—

Abstract

A method for controlling an optical device including a movable section including an optical section that refracts incident video image light and outputs the refracted video image light and a holding section that supports the optical section, and an actuator that causes the movable section to swing, the method including applying a drive signal to the actuator to cause the movable section to swing. The drive signal is a wave having a trapezoidal waveform, and the trapezoidal wave has a first flat section where first voltage is applied for a first period, a second flat section where second voltage higher than the first voltage is applied for a second period, and a third flat section where third voltage higher than the first voltage and lower than the second voltage is applied for a third period after the first voltage is applied and before the second voltage is applied.

First claim

What is claimed is:

1 . A method for controlling an optical device including a movable section including an optical section that refracts incident video image light in accordance with an angle of incidence of the video image light and outputs the refracted video image light and a holding section that supports the optical section, and an actuator that causes the movable section to swing, the method comprising
applying a drive signal to the actuator to cause the movable section to swing, wherein the drive signal is a wave having a trapezoidal waveform, and the trapezoidal wave has a first flat section where first voltage is applied for a first period, a second flat section where second voltage higher than the first voltage is applied for a second period, and a third flat section where third voltage higher than the first voltage and lower than the second voltage is applied for a third period after the first voltage is applied and before the second voltage is applied.

2 . The method for controlling an optical device according to claim 1 , wherein the third voltage is higher than an intermediate value between the first voltage and the second voltage.

3 . The method for controlling an optical device according to claim 1 ,
wherein each leg section of the trapezoidal wave has a first leg section that connects the first flat section to the third flat section, the third flat section, and a second leg section that connects the third flat section to the second flat section, and the first and second leg sections are each a straight line.

4 . The method for controlling an optical device according to claim 3 , wherein inclination of the second leg section with respect to the first flat section is smaller than inclination of the first leg section with respect to the first flat section.

5 . The method for controlling an optical device according to claim 1 ,
wherein each leg section of the trapezoidal wave has a first leg section that connects the first flat section to the third flat section, the third flat section formed of a straight line, and a second leg section that connects the third flat section to the second flat section, and the first and second leg sections each include a curve.

6 . The method for controlling an optical device according to claim 5 , wherein the first and second leg sections are each a quarter-cycle sinusoidal wave.

7 . An optical device comprising:
a movable section including an optical section that refracts incident video image light in accordance with an angle of incidence of the video image light and outputs the refracted video image light and a holding section that supports the optical section; an actuator that causes the movable section to swing; and a drive circuit that applies a drive signal to the actuator, wherein the drive signal is a wave having a trapezoidal waveform, and the trapezoidal wave has a first flat section where first voltage is applied for a first period, a second flat section where second voltage higher than the first voltage is applied for a second period, and a third flat section where third voltage higher than the first voltage and lower than the second voltage is applied for a third period after the first voltage is applied and before the second voltage is applied.

8 . An image display apparatus comprising:
the optical device according to claim 7 ; and a projection optical system that enlarges and projects the video image light outputted from the optical device.

Assignees

• Seiko Epson Corp

Inventors

• Hirakura Takao

Classifications

• G02B26/0833

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• G02F1/29 Primary

  for the control of the position or the direction of light beams, i.e. deflection · CPC title

• G02B26/10

  Scanning systems · CPC title