Virtual image display system

• US 8,854,735 B2
• Filed: 01/23/2012
• Issued: 10/07/2014
• Est. Priority Date: 02/16/2011
• 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): Pham, Thomas K
• Assistant Examiner(s): Patel, Vipin
• Application Number:
  US13/355,893
• Publication Number:
  US 20120206817A1
• Time in Patent Office: 988 Days
• Field of Search: 359630-633
• US Class Current: 359/633
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• 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 27/14 operating by reflection only
• CPC Class Codes: G02B 6/0045 by shaping at least a portion of the light guide

Abstract

A thickness of a tapered part provided at the deeper side (−X side) in a light guide direction of a light transmission member is smaller toward the deeper side, and thus, a reflection angle of ghost light that has passed through a fourth reflection surface provided with a half mirror layer and reached the light transmission member gradually becomes smaller within the tapered part and no longer satisfies a total reflection condition, and the light is ejected to the outside in the position diverging from an eye of an observer. That is, the tapered part may prevent the ghost light from reaching the eye and good see-through observation can be realized.

Claims

1. A virtual image display system comprising:

an image display device that forms image light;

a projection system that allows the image light output from the image display device to enter;

a light guide member having an integrated block shape that has a light guide part, a light-incident part allowing the image light from the projection system to enter the light guide part, and a light-exiting part that outputs the image light guided by the light guide part to the outside, and enables observation of the image light via the light-exiting part; and

a light transmission member that enables observation of external light by being combined with the light guide member,

wherein the light guide part has a first reflection surface and a second reflection surface that are provided in parallel to each other and enable light guide by total reflection,

the light-incident part has a third reflection surface at a predetermined angle with respect to the first reflection surface,

the light-exiting part has a fourth reflection surface at a predetermined angle with respect to the first reflection surface,

a half mirror is provided on the fourth reflection surface, and

the light transmission member includes a see-through aiding part at least having a first surface provided in parallel to a transmission surface opposed to the fourth reflection surface and the second reflection surface, and a light blocking part that is provided nearer a light guide direction side of the light guide member than the see-through aiding part and prevents visible light from the light transmission member from being guided to the light guide member once the visible light passes through the fourth reflection surface.

2. The virtual image display system according to claim 1, wherein the light blocking part is a tapered part having a thickness smaller toward the light guide direction side.

3. The virtual image display system according to claim 2, wherein the light transmission member has a second surface provided nearly in parallel to the first reflection surface and the first surface provided nearly in parallel to the second reflection surface, and

the tapered part includes a first tapered surface at an obtuse angle with respect to the first surface and a second tapered surface at an obtuse angle with respect to the second surface.

4. The virtual image display system according to claim 1, wherein the light blocking part is a part having a roughened surface.

5. The virtual image display system according to claim 1, wherein the light blocking part is a part having a surface to which light-absorbing paint is applied.

6. The virtual image display system according to claim 1, wherein a number of reflections in the light guide part of first image light output from a first partial area in the image display device is different from a number of reflections in the light guide part of second image light output from a second partial area different from the first partial area.

7. The virtual image display system according to claim 6, wherein a confinement direction is a direction in parallel to a section containing a first optical axis passing through the projection system and a normal line of the third reflection surface.

8. The virtual image display system according to claim 1, wherein the light guide member and the light transmission member are independently integrally molded by injection molding.

9. The virtual image display system according to claim 8, wherein the light guide member and the light transmission member are respectively molded using a heat polymerization resin material.