Virtual image display device

• US 8,564,883 B2
• Filed: 02/01/2012
• Issued: 10/22/2013
• Est. Priority Date: 02/04/2011
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Totani, Takahiro, Takagi, Masayuki, Komatsu, Akira, Takeda, Takashi, Miyao, Toshiaki
• Primary Examiner(s): Mack, Ricky
• Assistant Examiner(s): O'NEILL, GARY WILLIAM
• Application Number:
  US13/363,732
• Publication Number:
  US 20120200938A1
• Time in Patent Office: 629 Days
• Field of Search: 359/630, 359/632, 359/633, 345/7, 345/8, 345/9
• US Class Current: 359/633
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 6/0045 by shaping at least a portion of the light guide

Abstract

Image light reflected by a third reflective surface of a light incidence portion is propagated while being totally reflected by first and second reflective surfaces of a light guiding portion, is reflected by a fourth reflective surface of a light emission portion, and is incident to observer'"'"'s eye as a virtual image. At this time, the number of times of reflection of first image light, which is emitted from a first partial region of an image display device, in the light guiding portion, and the number of times of reflection of second image light, which is emitted from a second partial region of the image display device in the light guiding portion are different from each other, such that it is possible to take in the image light beams from the different partial regions of the image display device with a relatively wide angle of view.

Claims

1. A virtual image display device, comprising:

an image display device that emits image light;

a projective optical system that allows the image light emitted from the image display device to be incident; and

a light guiding member, comprising;

a light guiding portion;

a light incidence portion that allows the image light to be incident to the light guiding portion; and

a light emission portion that emits the image light guided by the light guiding portion to the outside, and that makes the image light visible through the light emission portion,

the light guiding portion having a first reflective surface and a second reflective surface that are disposed in parallel with each other and allow the light beam to be guided through a substantially total reflection,

the light incidence portion having a third reflective surface that makes a predetermined angle with respect to the first reflective surface,

the light emission portion having a fourth reflective surface that makes a predetermined angle with respect to the first reflective surface,

the image light from the image display device being guided into the light guiding member with a number of times of reflection that is different in each image light beam, and a plurality of image light beams formed in correspondence with the number of times of reflection are combined through the light emission portion and are emitted to the outside, and

the light guiding member being configured to increase a width of an angle of emission of the image light emitted from the light emission portion.

4. The virtual image display device according to claim 1,

the third reflective surface and the fourth reflective surface making an acute angle of 45°

or less with respect to the first reflective surface, respectively.

5. The virtual image display device according to claim 4,

the third reflective surface and the fourth reflective surface making the same angle with respect to the first reflective surface.

6. The virtual image display device according to claim 5,

the first optical axis passing through the projective optical system and a second optical axis of the image light emitted from the light emission portion being parallel with a normal line of the first reflective surface, respectively.

7. The virtual image display device according to claim 1,

the light guiding member including the light guiding portion, the light incidence portion, and the light emission portion being an integrally formed member of a block state.

8. The virtual image display device according to claim 7,

the light guiding member having the first to fourth reflective surfaces as a side surface, and a top surface and a bottom surface that are adjacent to the first to fourth reflective surfaces, respectively.

9. The virtual image display device according to claim 6,

the light guiding member having an external form of a polyhedral shape with at least one of a first end surface provided by removing a corner between the first reflective surface and the third reflective surface, and a second end surface provided by removing a corner between the first reflective surface and the fourth reflective surface.

10. The virtual image display device according to claim 1,

the light guiding member being integrally molded by injection molding.

11. The virtual image display device according to claim 10,

the light guiding member being molded from a thermal polymerization type resin material.

12. The virtual image display device according to claim 1,

the light guiding member comprising a hard coat on the first reflective surface and the second reflective surface.

13. The virtual image display device according to claim 1, further comprising:

a wedge-shaped light transmitting member that has a transmissive surface that is opposite to the fourth reflective surface; and

a half mirror provided on the fourth reflective surface.

14. The virtual image display device according to claim 13,

the half mirror having a transmittance that is adjusted by controlling a film thickness of an Ag film.

15. The virtual image display device according to claim 1,

the third reflective surface being provided with a substantially total reflection coating.

2. A virtual image display device, comprising:

an image display device that forms image light;

a projective optical system that allows the image light emitted from the image display device to be incident; and

a light guiding member, comprising;

a light guiding portion;

a light incidence portion that allows the image light to be incident to the light guiding portion; and

a light emission portion that emits the image light guided by the light guiding portion to the outside, and that makes the image light visible through the light emission portion,

the light guiding portion having a first reflective surface and a second reflective surface that are disposed in parallel with each other and allow light to be guided through a substantially total reflection,

the light incidence portion having a third reflective surface that makes a predetermined angle with respect to the first reflective surface,

the light emission portion having a fourth reflective surface that makes a predetermined angle with respect to the first reflective surface, and

the number of times of reflection of a first image light beam, emitted from a first partial region, which forms a first projection image in the image display device, in the light guiding portion, and the number of times of reflection of a second image light beam, emitted from a second partial region, which forms a second projection image in the image display device, different from the first partial region in regard to a confinement direction in which a return of an optical path due to reflection occurs at the time of light-guiding, in the light guiding portion, being different from each other.

3. The virtual image display device according to claim 2,

the confinement direction being a direction that is parallel with a cross-section including a first optical axis passing through the projective optical system and a normal line of the third reflective surface.

16. A virtual image display device, comprising:

an image display device that emits a plurality of image light beams;

a projective optical system that allows the image light emitted from the image display device to be incident; and

a light guiding member, comprising;

a light guiding portion; and

a light incidence portion that allows the image light to be incident to the light guiding portion, and a light emission portion that emits the image light guided by the light guiding portion to the outside, and that makes the image light visible through the light emission portion,

the light guiding portion having a first reflective surface and a second reflective surface that are disposed in parallel with each other and allow light to be guided through a substantially total reflection,

the light incidence portion having a third reflective surface that defines an opening width and makes a predetermined angle with respect to the first reflective surface,

the light emission portion having a fourth reflective surface that makes a predetermined angle with respect to the first reflective surface,

each of the plurality of light beams being propagated in three different modes and substantially totally reflected at a different reflection angle such that a first reflection angle of the plurality of light beams is greater than a second reflection angle of the plurality of light beams, and the second reflection angle being greater than a third reflection angle of the plurality of light beams, and

the light guiding member being configured to increase a width of an angle of emission of the image light emitted from the light emission portion.

17. The virtual image display device according to claim 16, the plurality of light beams being subject to a substantially total reflection of three, five and seven times, each forming a projection image at a left-side, center and right-side of an effective display region.