Image display device and driving device

Patent metadata

Field	Value
Publication number	US-11322057-B2
Application number	US-202017103771-A
Country	US
Kind code	B2
Filing date	Nov 24, 2020
Priority date	Jun 27, 2018
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

An image display device includes: a light source; a screen on which an image is formed when light from the light source is applied thereto; an optical system configured to generate a virtual image by light from the screen; an actuator configured to move the screen in an optical axis direction; a position detector configured to detect a movement position of the screen; a servo circuit configured to cause the movement of the screen by the actuator to follow a target waveform on the basis of a signal from the position detector; and a correction circuit configured to reduce a deviation between a timing to move the screen by the servo circuit and a timing to form the image on the screen.

First claim

What is claimed is:

1. An image display device comprising:
a light source;
a screen on which an image is formed when light from the light source is applied thereto;
an optical system configured to generate a virtual image by light from the screen;
an actuator configured to reciprocate the screen along an optical axis of the light that passes through the screen;
a position detector configured to detect a position of the screen;
a servo circuit configured to cause a reciprocating motion of the screen by the actuator to follow a target waveform on the basis of a signal from the position detector; and
a correction circuit configured to reduce a deviation between a timing to move the screen by the servo circuit and a timing to form the image on the screen.

2. The image display device according to claim 1 , wherein the correction circuit includes a phase correction circuit configured to make a phase of the target waveform closer to a phase of a drive waveform of the screen by the actuator, and supplies the target waveform corrected by the phase correction circuit, to the servo circuit.

3. The image display device according to claim 2 , further comprising a drive signal generation circuit configured to generate a drive signal for driving the light source, wherein
the correction circuit supplies the corrected target waveform to the drive signal generation circuit and synchronizes the drive signal with the phase of the target waveform corrected by the phase correction circuit.

4. The image display device according to claim 2 , wherein the phase correction circuit starts supplying the corrected target waveform to the servo circuit after a predetermined time elapses from start of control by the servo circuit.

5. The image display device according to claim 1 , further comprising a drive signal generation circuit configured to generate a drive signal for driving the light source, wherein
the correction circuit includes a phase correction circuit configured to make a phase of the target waveform closer to a phase of the drive waveform, and supplies the corrected target waveform to the drive signal generation circuit to synchronize the drive signal with the phase of the target waveform corrected by the phase correction circuit.

6. The image display device according to claim 1 , wherein the correction circuit further includes an amplitude correction circuit configured to detect an amplitude deviation between the target waveform before correction and a drive waveform of the screen by the actuator and amplify the drive signal for the actuator such that the detected amplitude deviation is reduced.

7. The image display device according to claim 1 , wherein the correction circuit detects a time deviation between the target waveform before correction and a drive waveform of the screen by the actuator, and makes a phase of the target waveform closer to a phase of the drive waveform on the basis of the detected time deviation.

8. The image display device according to claim 1 , wherein the correction circuit stores a time deviation between the target waveform before correction and a drive waveform of the screen by the actuator in advance, and makes a phase of the target waveform closer to a phase of the drive waveform on the basis of the stored time deviation.

9. The image display device according to claim 1 , wherein
the position detector outputs a pulse signal in accordance with the movement of the screen, and outputs an origin signal in accordance with the screen being positioned at an origin position,
the image display device further comprises a counter configured to count the pulse signal outputted from the position detector, and
the counter is reset on the basis of the origin signal.

10. A driving device comprising:
a light source;
an optical member on which light from the light source is incident;
an actuator configured to reciprocate the optical member along an optical axis of the light that passes through the optical member;
a position detector configured to detect a position of the optical member;
a servo circuit configured to cause a reciprocating motion of the optical member by the actuator to follow a target waveform on the basis of a signal from the position detector; and
a correction circuit configured to reduce a deviation between a timing to drive the optical member by the servo circuit and a timing to drive the light source.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Uragami Susumu
• Yamamoto Yuta
• Furuya Hiroyuki
• Kashiwabara Yoshiro

Classifications

• B60K35/50

  Instruments characterised by their means of attachment to or integration in the vehicle (B60K35/231 takes precedence) · CPC title

• B60K35/90

  Calibration of instruments, e.g. setting initial or reference parameters; Testing of instruments, e.g. detecting malfunction · CPC title

• B60K35/10

  Input arrangements, i.e. from user to vehicle, associated with vehicle functions or specially adapted therefor · CPC title

• B60K35/80

  Arrangements for controlling instruments · CPC title

• B60K35/22

  Display screens · CPC title