Image combiner and image display device

• US 8,035,872 B2
• Filed: 06/20/2005
• Issued: 10/11/2011
• Est. Priority Date: 06/29/2004
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Ouchi, Yumiko
• Primary Examiner(s): SHAFER, RICKY D
• Application Number:
  US11/630,621
• Publication Number:
  US 20070285752A1
• Time in Patent Office: 2,304 Days
• Field of Search: 359/487, 359/495, 359/629, 359/631, 359/633, 359/13, 359/15, 359/630, 345/7, 345/8
• US Class Current: 359/13
• 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 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings

Abstract

The present invention aims to provide an image combiner and an image display device which can easily have a wide field of view and reduce a thickness of a substrate while reducing loss of light intensity by means of a PBS. An image combiner includes a substrate transparent to visible light; and a polarization beam splitter installed in the substrate to reflect a light flux introduced into the substrate from an image-display element and to make the light flux incident on an exit pupil outside the substrate. An exit angle θ₀ at which a principal ray of the light flux emitted from a center of a display surface of the image-display element is emitted from a surface of the substrate toward a center of the exit pupil satisfies a condition of 3°≦θ₀.

Claims

1. An image combiner comprising:

a lens element, including a convex lens and a concave lens, that guides a light flux from an image forming means;

a substrate disposed in front of a user'"'"'s eye, the substrate being transparent to visible light, and introducing the light flux emitted from the lens element;

a reflection region inner-reflecting the light flux introduced from the image forming means into the substrate, the reflection region being a part of one surface of the substrate; and

a polarization beam splitter to which the light flux reflected at the reflection region enters twice and which makes the light flux entering for a second time incident on the user'"'"'s eye outside the substrate, the polarization beam splitter being installed in the substrate, wherein

at least an angle θ

₀ between a line that is perpendicular to the reflection region and a principal ray of a portion flux of the light flux that directly enters the user'"'"'s eye satisfies a condition of 3°

≦

θ

₀, the portion flux being a flux emitted from a center of a display surface of the image forming means; and

an inclination direction of the light flux heading into the user'"'"'s eye relative to the line that is perpendicular is set so to make a display position of a virtual image of the display surface to be at a position in an obliquely downward direction from the user'"'"'s eye.

2. The image combiner according to claim 1, wherein

an angle θ

₂ at which said polarization beam splitter is set relative to the reflection region satisfies a condition of 30°

<

θ

₂<

42°

.

3. The image combiner according to claim 2, wherein

the angle θ

₂ satisfies a condition of 35°

<

θ

₂<

42°

.

4. The image combiner according to claim 3, wherein:

the substrate includes a reflection member which reflects the light flux passed through the polarization beam splitter to make the light flux that is reflected become re-incident on the polarization beam splitter.

5. The image combiner according to claim 4, wherein

the reflection member is a concave mirror.

6. The image combiner according to claim 4, wherein

at least one of the reflection member and the polarization beam splitter have a reflection wavelength selectivity to select a wavelength of the light flux.

7. The image combiner according to claim 4, wherein

the reflection member is a reflective-type holographic optical element formed to have a concave surface.

8. The image combiner according to claim 7, wherein

the reflective-type holographic optical element has no optical power.

9. The image combiner according to claim 2, wherein:

the substrate includes a reflection member that reflects the light flux passed through the polarization beam splitter to make the light flux that is reflected become re-incident on the polarization beam splitter.

10. The image combiner according to claim 9, wherein

the reflection member is a concave mirror.

11. The image combiner according to claim 9, wherein

at least one of the reflection member and the polarization beam splitter has a reflection wavelength selectivity to select a wavelength of the light flux.

12. The image combiner according to claim 9, wherein

the reflection member is a reflective-type holographic optical element formed to have a concave surface.

13. The image combiner according to claim 12, wherein

the reflective-type holographic optical element has no optical power.

14. An image display device comprising:

the image combiner according to claim 1, and the image forming means emitting the light flux into the substrate.