Image display apparatus and optical device

Patent metadata

Field	Value
Publication number	US-2021088797-A1
Application number	US-202017116984-A
Country	US
Kind code	A1
Filing date	Dec 9, 2020
Priority date	Jul 5, 2018
Publication date	Mar 25, 2021
Grant date	—

Abstract

An image display apparatus 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 support base supporting the actuator; and a dynamic damper installed on a non-movable part on the support base.

First claim

What is claimed is:

1 . An image display apparatus 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 move the screen in an optical axis direction; a support base supporting the actuator; and a dynamic damper installed on a non-movable part on the support base.

2 . The image display apparatus according to claim 1 , wherein
the actuator includes:
a holder holding the screen;
a coil mounted on the holder; and
a magnetic circuit installed on the support base and configured to apply a magnetic field to the coil,
the magnetic circuit includes a magnetic cover placed on an upper surface of the magnetic circuit and functioning as a yoke for the magnetic circuit, and the dynamic damper is installed on an upper surface of the magnetic cover.

3 . The image display apparatus according to claim 2 , wherein a plurality of the dynamic dampers are installed on the upper surface of the magnetic cover.

4 . The image display apparatus according to claim 3 , wherein the dynamic dampers are installed at positions symmetrical with respect to a center of the magnetic cover, respectively.

5 . The image display apparatus according to claim 1 , wherein the support base is supported by a fixed base via a damper.

6 . The image display apparatus according to claim 1 , wherein a plurality of the dynamic dampers having different resonance frequencies are installed on the non-movable part.

7 . The image display apparatus according to claim 6 , wherein
the plurality of the dynamic dampers each include a mass member and a damper connecting the mass member to the non-movable part, and the resonance frequencies of the plurality of the dynamic dampers are made different by uniformly setting weights of the mass members of the respective dynamic dampers and making hardnesses of the respective dampers different from each other.

8 . An optical device comprising:
a light source; an optical system to which light from the light source is guided; an actuator configured to move the optical system; a support base supporting the actuator; and a dynamic damper installed on a non-movable part on the support base.

9 . The optical device according to claim 8 , wherein
the optical system includes a screen on which an image is formed when the light from the light source is applied thereto, and the actuator drives the screen in an optical axis direction.

10 . The optical device according to claim 8 , wherein
the optical system includes an optical member on which the light from the light source is incident, and the actuator drives the optical member to change a travelling direction of the light.

11 . The optical device according to claim 10 , wherein
the optical member is a mirror, and the actuator rotates the mirror about at least one rotation axis.

12 . The optical device according to claim 8 , further comprising a controller configured to detect whether an abnormality has occurred in the movement of the optical system and prohibit application of the light when the abnormality is detected.

13 . The optical device according to claim 12 , wherein the controller detects an abnormality of the actuator on the basis of a conduction state of an electric signal to the actuator, and prohibits application of the light when the abnormality of the actuator is detected.

14 . The optical device according to claim 13 , wherein
the actuator drives the optical system by electromagnetic force generated between a coil and a magnet, the optical device further comprises a voltage measurement circuit configured to measure a voltage applied to the coil, and the controller detects the abnormality of the actuator when a voltage outputted from the voltage measurement circuit during operation of the optical system is smaller than a predetermined threshold.

15 . The optical device according to claim 12 , further comprising a position detector configured to detect a movement position of the optical system, wherein
the controller monitors position detection operation in the position detector and performs detection of an abnormality of the position detector during operation of the optical system, and prohibits application of the light when the abnormality of the position detector is detected.

16 . The optical device according to claim 15 , wherein
the position detector includes an encoder configured to detect a position of the optical system and output a detection signal, and a multiplication circuit configured to multiply the detection signal outputted from the encoder, and the controller detects the abnormality of the position detector when a multiplication signal is not outputted from the multiplication circuit.

17 . The optical device according to claim 12 , wherein, in initial control, the controller detects whether an abnormality has occurred in the movement of the optical system.

18 . The optical device according to claim 12 , further comprising:
a position detector configured to detect a movement position of the optical system; and a servo circuit configured to cause the movement of the optical system by the actuator to follow a target waveform on the basis of a signal from the position detector, wherein during servo control of the optical system by the servo circuit, the controller prohibits application of the light on the basis of a difference between a drive waveform of the optical system and the target waveform.

19 . The optical device according to claim 18 , wherein, during servo control of the optical system by the servo circuit, the controller prohibits application of the light when a cumulative value of the difference between the drive waveform of the optical system and the target waveform is larger than a predetermined threshold.

20 . The optical device according to claim 18 , wherein the controller prohibits application of the light on the basis of the difference in a one-frame period for driving the optical system.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Uragami Susumu
• Furuya Hiroyuki
• Kurozuka Akira
• Yamamoto Yuta
• Yamaguchi Mitsutaka
• Kashiwabara Yoshiro

Classifications

• B60K35/235

  with means for detecting the driver's gaze direction or eye points · CPC title

• B60K35/53

  Movable instruments, e.g. slidable · CPC title

• B60K35/10

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

• B60K35/22

  Display screens · CPC title

• H04N13/395

  with depth sampling, i.e. the volume being constructed from a stack or sequence of two-dimensional [2D] image planes · CPC title