Image display apparatus

• US 10,613,321 B2
• Filed: 11/30/2018
• Issued: 04/07/2020
• Est. Priority Date: 03/11/2015
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nakamura, Naoki, Ichii, Daisuke, Atsuumi, Hiromichi, Miyatake, Naoki, Hayashi, Yuki
• Primary Examiner(s): Hasan, Mohammed A
• Application Number:
  US16/206,178
• Publication Number:
  US 20190204591A1
• Time in Patent Office: 494 Days
• Field of Search: 359631, 359630, 359632, 359634, 345 7, 345 8
• CPC Class Codes: B81B 2201/04 Optical MEMS
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/013 comprising a combiner of particular shape, e.g. curvature
• CPC Class Codes: G02B 2027/0141 characterised by the informative content of the display
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 26/126 including curved mirrors
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/104 for use with scanning systems scanning systems G02B26/10
• CPC Class Codes: G03B 21/2013 Plural light sources
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T

Abstract

An image display apparatus includes a light source device including a light source unit; a scanning optical system including an image forming unit on which an intermediate image is formed by light from the light source unit; and a virtual image optical system configured to guide light of the intermediate image by using a reflecting mirror and a curved transmissive reflection member. The scanning optical system includes an optical scanning unit configured to scan the light from the light source unit in a main scanning direction and a sub-scanning direction of the image forming unit. The image forming unit is a transmissive member curved with a convex surface toward the reflecting mirror.

Claims

1. An image display apparatus, comprising:

a light source device including a light source unit;

a scanning optical system including an image forming unit on which an intermediate image is formed by light from the light source unit; and

a virtual image optical system configured to guide light of the intermediate image by using a reflecting mirror and a curved transmissive reflection member, wherein;

the scanning optical system includes an optical scanning unit configured to two-dimensionally scan the light from the light source unit in a main scanning direction and a sub-scanning direction perpendicular to the main scanning direction of the image forming unit, and

in an XYZ three-dimensional coordinate system where an X direction corresponds to the main scanning direction, a Y direction corresponds to the sub-scanning direction, and a Z direction is perpendicular to both the X direction and the Y direction, the image forming unit is a transmissive member curved in the X direction of the curved transmissive reflection member.

2. The image display apparatus according to claim 1, wherein |Rx|<

|Ry| is satisfied, where Rx is a radius of curvature at a center of the image forming unit corresponding to the longitudinal direction when the intermediate image is displayed on the curved transmissive reflection member, and Ry is a radius of curvature at the center of the image forming unit corresponding to a transverse direction when the intermediate image is displayed on the curved transmissive reflection member.

3. The image display apparatus according to claim 1, wherein, in an XY plane of the XYZ three-dimensional coordinate system, an optical length of light incident on one end of the reflecting mirror from the optical scanning unit through one end of the image forming unit is different from an optical length of light incident on another end of the reflecting mirror from the optical scanning unit through an opposite end of the image forming unit.

4. The image display apparatus according to claim 1, wherein the scanning optical system does not include an optical element having a condensing effect or an optical element having a diverging effect between the optical scanning unit and the image forming unit.

5. The image display apparatus according to claim 1, wherein the light source device includes a condensing element for converging light on the optical scanning unit, the condensing element having a focal length f of greater than 150 mm with respect to light having a wavelength of 587.56 nm.

6. The image display apparatus according to claim 1, wherein:

the light source unit includes independent light sources corresponding to red, green, and blue, respectively, and collimator lenses and apertures corresponding to the respective light sources, the collimator lenses and apertures making parallel light emitted from the respective light sources; and

the aperture corresponding to the red light source has an opening area greater than both that of the aperture corresponding to the green light source and that of the aperture corresponding to the blue light source.

7. The image display apparatus according to claim 1, wherein the light source unit is a laser or an LED.

8. The image display apparatus according to claim 1, wherein the curved transmissive reflection member is a front windshield of a moving body.

9. The image display apparatus of claim 1, wherein the curved transmissive reflection member is curved in the X direction.