Image projection device and head-up display device provided with image projection device

Patent metadata

Field	Value
Publication number	US-2019107714-A1
Application number	US-201816216145-A
Country	US
Kind code	A1
Filing date	Dec 11, 2018
Priority date	Jun 28, 2016
Publication date	Apr 11, 2019
Grant date	—

Abstract

An image projection device includes an emitting unit, a shaping unit, an adjusting unit, a scanning unit, and a projection optical system. The projection optical system is disposed such that a position of a front side principal plane of the projection optical system is at a position which is separated from the scanning unit by a focal length of the projection optical system.

First claim

1 . An image projection device that projects light representing information onto a projection target surface, comprising:
an emitting unit configured to emit a light beam; a shaping unit configured to shape a shape of the light beam emitted from the emitting unit; an adjusting unit configured to adjust convergence and divergence of the light beam shaped by the shaping unit such that an imaging point of the light beam is positioned on the projection target surface; a scanning unit configured to deflection scan the light beam whose convergence and divergence are adjusted by the adjusting unit; and a projection optical system including at least one optical element, the projection optical system being disposed on a path of the light beam from the scanning unit to the projection target surface and being configured to project the light beam, which is deflection scanned by the scanning unit, onto the projection target surface, the projection optical system being disposed such that a position of a front side principal plane of the projection optical system is at a position which is separated from the scanning unit by a focal length of the projection optical system.

2 . The image projection device according to claim 1 , wherein
the adjusting unit is a reflection optical element configured to reflect the light beam whose convergence and divergence are adjusted.

3 . The image projection device according to claim 2 , wherein
the adjusting unit and the scanning unit are provided by a common element.

4 . The image projection device according to claim 3 , wherein
the adjusting unit includes a reflecting surface which is formed on a convex surface and which reflects the light beam.

5 . The image projection device according to claim 3 , wherein
the adjusting unit includes a reflecting surface which is formed on a concave surface and which reflects the light beam.

6 . The image projection device according to claim 5 , further comprising:
a diverging unit between the shaping unit and the adjusting unit configured to cause the light beam shaped by the shaping unit to diverge and to cause the divergent light to enter the adjusting unit.

7 . The image projection device according to claim 4 , further comprising:
a converging unit between the shaping unit and the adjusting unit configured to cause the light beam shaped by the adjusting unit to converge and to cause the convergent light to enter the adjusting unit.

8 . The image projection device according to claim 3 , wherein
the adjusting unit is configured to change a curvature of the reflecting surface of the adjusting unit according to a projection distance from a rear side principal plane of the projection optical system to the projection target surface to adjust the convergence and the divergence of the light beam.

9 . The image projection device according to claim 1 , wherein
the projection optical system has an fθ characteristic.

10 . The image projection device according to claim 1 , wherein
the projection optical system has an Asin θ characteristic.

11 . The image projection device according to claim 1 , wherein
the projection target surface includes a screen having a micromirror array.

12 . The image projection device according to claim 1 , wherein
the projection target surface includes a screen having a microlens array.

13 . A head-up display device comprising:
the image projection device according to claim 1 .

14 . An image projection device that projects light representing information onto a screen, comprising:
a light diode configured to emit a light beam; a collimator configured to shape a shape of the light beam emitted from the light diode; a MEMS mirror configured to
adjust convergence and divergence of the light beam shaped by the collimator such that an imaging point of the light beam is positioned on the screen, and
after adjusting the convergence and divergence of the light beam, deflection scan the light beam; and
a projection optical system including at least one optical element, the projection optical system being disposed on a path of the light beam from the MEMS mirror to the screen and being configured to project the light beam, which is deflection scanned by the MEMS mirror, onto the screen, the projection optical system being disposed such that a position of a front side principal plane of the projection optical system is at a position which is separated from the MEMS mirror by a focal length of the projection optical system.

15 . An image projection device that projects light representing information onto a screen, comprising:
a light diode configured to emit a light beam; a collimator configured to shape a shape of the light beam emitted from the light diode; a variable focal length lens configured to adjust convergence and divergence of the light beam shaped by the collimator; a MEMS mirror configured to deflection scan the light beam whose convergence and divergence are adjusted by the variable focal length lens; and a projection optical system including at least one optical element, the projection optical system being disposed on a path of the light beam from the MEMS mirror to the screen and being configured to project the light beam, which is deflection scanned by the MEMS mirror, onto the screen, the projection optical system being disposed such that a position of a front side principal plane of the projection optical system is at a position which is separated from the MEMS mirror by a focal length of the projection optical system.

Assignees

• Denso Corp

Inventors

• Ishihara Kazuyuki
• Ando Hiroshi

Classifications

• G02B27/0101 Primary

  characterised by optical features (G02B27/0172 takes precedence) · CPC title

• G02B27/01

  Head-up displays · CPC title

• G02B27/0031

  for scanning purposes · CPC title

• G02B26/10

  Scanning systems · CPC title

• H04N9/3161

  using laser light sources (using laser beams scanning the display screen H04N9/3129) · CPC title