Optical device, projector, and method for controlling optical device

Patent metadata

Field	Value
Publication number	US-11467476-B2
Application number	US-202017036953-A
Country	US
Kind code	B2
Filing date	Sep 29, 2020
Priority date	Sep 30, 2019
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

An optical device includes a movable section including an optical section that deflects video light in accordance with the angle of incidence of the video light incident on a light incident surface and outputs the deflected video light and a holder that supports the optical section, an actuator that rotates the movable section around a first axis, an actuator that rotates the movable section around a second axis, a drive circuit that supplies the actuator with a first drive signal and the actuator with a second drive signal, and a sensor disposed in a position different from the positions on the first and second axes detects the position of the optical section, and the drive circuit adjusts the first and second drive signals in accordance with the position of the optical section detected with the sensor.

First claim

What is claimed is:

1. An optical device comprising:
a movable section including an optical section that has a light incident surface on which video light is incident, deflects the video light in accordance with an angle of incidence of the video light incident on the light incident surface, and outputs the deflected video light and a holder that supports the optical section;
a first actuator that rotates the movable section around a first axis;
a second actuator that rotates the movable section around a second axis that intersects the first axis;
a drive circuit that supplies the first actuator with a first drive signal that drives the first actuator and the second actuator with a second drive signal that drives the second actuator; and
a sensor that detects a position of the optical section,
wherein the drive circuit adjusts the first and second drive signals in accordance with the position of the optical section detected with the sensor, and
the sensor is disposed in a position different from positions on the first and second axes.

2. The optical device according to claim 1 ,
wherein the first and second drive signals are out of phase by a predetermined phase difference, and
the sensor alternately carries out a first process of detecting the position of the optical section in accordance with the rotation around the first axis and a second process of detecting the position of the optical section in accordance with the rotation around the second axis.

3. The optical device according to claim 2 ,
wherein the predetermined phase difference is a phase difference corresponding to a quarter cycle of the first drive signal.

4. The optical device according to claim 3 ,
wherein a waveform of the first drive signal changes in a first time segment for which the first process is carried out, and
a waveform of the second drive signal changes in a second time segment for which the second process is carried out.

5. The optical device according to claim 1 ,
wherein the sensor outputs a detection signal having a waveform according to a change in the position of the optical section, and
the drive circuit determines an amount of rotation of the movable section based on a difference between a maximum and a minimum of sample values of the detection signal.

6. The optical device according to claim 1 ,
wherein the holder is a quadrangular frame that surrounds the optical section,
in a plan view viewed along a direction in which the video light is incident, a first edge of the holder that is an edge extending from a first corner of four corners of the holder along the first axis intersects the second axis, and a second edge of the holder that is an edge extending from the first corner along the second axis intersects the first axis, and
the sensor is disposed in the holder.

7. The optical device according to claim 6 ,
wherein the sensor is disposed in a position separate from the first axis by a distance greater than or equal to half a length of the second edge and separate from the second axis by a distance greater than or equal to half a length of the first edge.

8. The optical device according to claim 6 ,
wherein the sensor is disposed in a position where a distance from the first axis in a direction along the second axis is equal to a distance from the second axis in a direction along the first axis.

9. The optical device according to claim 6 ,
wherein the sensor is disposed at the first corner.

10. The optical device according to claim 6 ,
wherein the first actuator includes a first magnet provided in the movable section and a first coil to which a current according to the first drive signal is supplied,
the second actuator includes a second magnet provided in the movable section and a second coil to which a current according to the second drive signal is supplied, and
the sensor is a magnetism sensor including a Hall device and is disposed in a position where the sensor does not overlap with the first or second actuator in the plan view.

11. A projector comprising the optical device according to claim 1 .

12. A method for controlling an optical device including a movable section including an optical section that has a light incident surface on which video light is incident, deflects the video light in accordance with an angle of incidence of the video light incident on the light incident surface, and outputs the deflected video light and a holder that supports the optical section, a first actuator that rotates the movable section around a first axis, and a second actuator that rotates the movable section around a second axis that intersects the first axis, the method comprising:
causing a sensor disposed in a position different from positions on the first and second axes to detect a position of the optical section, and
adjusting a first drive signal that drives the first actuator and a second drive signal that drives the second actuator in accordance with the position of the optical section detected with the sensor.

Assignees

• Seiko Epson Corp

Inventors

• Hirakura Takao

Classifications

• G02B26/0875

  by means of one or more refracting elements · CPC title

• H01F7/081

  Magnetic constructions · CPC title

• H01F7/122

  by permanent magnets {(H01F7/1615, H01F7/1646 take precedence)} · CPC title

• H01F7/0205

  Magnetic circuits with PM in general · CPC title

• H01F7/064

  Circuit arrangements for actuating electromagnets (circuit arrangements for obtaining special operating characteristics H01F7/18; driving circuits for electromagnets making use of a switching regulator H01H47/325) · CPC title