Virtual image display device

• US 8,587,869 B2
• Filed: 01/30/2012
• Issued: 11/19/2013
• 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, Miyao, Toshiaki, Komatsu, Akira, Takeda, Takashi
• Primary Examiner(s): CHOI, WILLIAM C
• Application Number:
  US13/361,249
• Publication Number:
  US 20120200937A1
• Time in Patent Office: 659 Days
• Field of Search: 359/629, 359/630
• US Class Current: 359/630
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• 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 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/0045 by shaping at least a portion of the light guide
• CPC Class Codes: H04N 13/111 Transformation of image signals corresponding to virtual viewpoints, e.g. spatial image interpolation
• CPC Class Codes: H04N 13/332 Displays for viewing with the aid of special glasses or head-mounted displays [HMD]
• CPC Class Codes: H04N 13/344 with head-mounted left-right displays

Abstract

A half mirror layer has an angle dependency in which when an angle of incidence becomes larger than the angle of incidence range of image light, reflectance increases, such that it is possible to prevent unintended light, which is emitted to a light transmitting member from a light guiding member and is reflected inside a light transmitting member, from being returned to a light emission portion of the light guiding member after passing through the half mirror layer as a reflective film at a relatively large angle of incidence. Therefore, it is possible to prevent the image light passed through the light transmitting member from becoming ghost light while mitigating the demand for increasing processing accuracy of the light transmitting member, and bonding accuracy between the light guiding member and the light transmitting member.

Claims

1. A virtual image display device, comprising:

a light guiding member, comprising;

a light guiding portion;

a light incidence portion that allows 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;

a light transmitting member that makes up a see-through portion that allows external light to be observed through a combination with the light guiding member; and

a reflective film having a light transmitting property and an angle dependency in which when an angle of incidence becomes larger than an angle of incidence range of the image light, reflectance increases are provided between the light emission portion and the light transmitting member.

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

the reflective film having a characteristic in which the reflectance varies in a stepwise fashion with a predetermined lower limit angle given as a boundary, and reflects light having the angle of incidence larger than the lower limit angle and uniformly transmits light having the angle of incidence smaller than the lower limit angle.

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

the reflective film being formed by laminating plural kinds of films.

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

the reflective film having a structure in which a metallic reflective film and a dielectric multi-layer film are laminated.

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

the reflective film further comprising a semi-transmissive reflective film comprising an Ag film whose transmittance is adjusted as the metallic reflective film.

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

the reflective film having a reflectance of 10% to 50% with respect to the image light.

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

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,

the light transmitting member having a wedge-shaped member having a light transmitting surface bonded to the fourth reflective surface of the light emission portion through the reflective film, and

the reflective film being disposed between the fourth reflective surface and the light transmitting surface.

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

the light transmitting member having a first surface and a second surface that are disposed in parallel with the first reflective surface and the second reflective surface, respectively.

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

the light guiding portion having an end surface that blocks ghost light at a position of at least one of portions between the first reflective surface and the fourth reflective surface, and between the first reflective surface and the third reflective surface.

10. The virtual image display device according to claim 7, further comprising:

an image display device that forms image light; and

a projective optical system that makes the image light emitted from the image display device be incident,

the number of times of reflection of a first image light emitted from a first partial region in the image display device in the light guiding portion, and the number of times of reflection of a second image light emitted from a second partial region 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.

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

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.

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

each of the light guiding member and the light transmitting member being integrally molded independently by an injection molding.

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

the light guiding member and the light transmitting member being molded from a thermal polymerization type resin material, respectively.