Optical apparatus having ocular optical system

• US 5,831,712 A
• Filed: 07/31/1997
• Issued: 11/03/1998
• Est. Priority Date: 11/02/1994
• Status: Expired due to Term

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Tabata, Seiichiro, Ogasawara, Yuji
• Primary Examiner(s): DANG, HUNG XUAN
• Application Number:
  US08/903,921
• Time in Patent Office: 460 Days
• Field of Search: 351/158, 351/41, 359/40, 359/83, 359/63, 359/630, 359/631, 359/633, 359/473, 345/8, 349/8, 349/9
• US Class Current: 351/158
• 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

Abstract

An optical apparatus, e.g. a head-mounted display apparatus, which enables observation of a favorable image by eliminating flare and ghost images caused by unwanted light coming in through the gap between an observer'"'"'s eyeball and an optical unit of the apparatus. Display light of an electronic image emanating from a liquid crystal display device and outside world light coming in through a liquid crystal shutter (7) are p-polarized light and therefore pass through a polarizing plate (8) and reach an observer'"'"'s eyeball (1) without any loss. Meanwhile, light that undesirably comes in through the gap between the observer'"'"'s face and the optical unit is generally natural light and hence unpolarized. Therefore, when the unwanted light passes through the polarizing plate (8) after being reflected from the eyeball (1) or a mirror (3), the light intensity reduces to 1/2. Although the light is successively reflected by the concave mirror (3) and the half-mirror (2) to reach the eyeball (1), the intensity ratio of the ghost image to the normal electronic image becomes 1/2. Thus, an electronic image of improved contrast can be observed.

Claims

1. An image display apparatus comprising:

an ocular optical system for leading an image to an observer'"'"'s eyeball; and

a reflecting mirror for reflecting said image,

said ocular optical system and reflecting mirror being contained in an optical unit, said image display apparatus further comprising;

a visor formed from a polarizing plate provided on an observer'"'"'s side of said optical unit; and

a polarizing plate provided between said reflecting mirror and said observer'"'"'s eyeball, said polarizing plate having a polarized light transmitting direction perpendicularly intersecting a polarized light transmitting direction of said visor.

4. An image display apparatus according to claim 1, 2 or 3, further comprising means for supporting a display device for displaying an image, said ocular optical system and said reflecting mirror on an observer'"'"'s head.

2. An image display apparatus comprising:

an image display means for forming a polarized light image; and

an ocular optical system for leading said polarized light image to an observer'"'"'s eyeball,

wherein said image display means has an illuminating device and a display device, said display device being disposed to face opposite and adjacent to said illuminating device,

wherein said ocular optical system has a reflecting mirror for reflecting said image,

wherein a polarizing plate is nonrotatably secured between said ocular optical system and said observer'"'"'s eyeball so as to reduce an intensity of leakage light entering said ocular optical system through a gap at a periphery of said observer'"'"'s eyeball and is led to said observer'"'"'s eyeball through said ocular optical system in order to prevent occurrence of flare or a ghost image which would otherwise be caused by said leakage light, and

wherein said image display means and said ocular optical system are provided in combination for one eyeball.

5. An image display apparatus according to claim 2 or 3, wherein said ocular optical system has a half-mirror disposed between said image display means and said reflecting mirror to transmit and reflect or to reflect and transmit light from said reflecting mirror toward said observer'"'"'s eyeball so that light from said image display means is successively transmitted or reflected by said half-mirror, reflected by said reflecting mirror, reflected or transmitted by said half-mirror and passes through said polarizing plate disposed between said ocular optical system and said observer'"'"'s eyeball to reach said observer'"'"'s eyeball.

6. An image display apparatus according to claim 5, further comprising:

a first quarter-wave plate disposed in an optical path extending from said display device to said half-mirror so that a crystallographic axis direction of said first quarter-wave plate is at 45 degrees to a polarized light transmitting direction of said polarizing plate disposed between the ocular optical system and the observer'"'"'s eyeball; and

a second quarter-wave plate disposed in an optical path extending from said half-mirror to said polarizing plate so that a second crystallographic axis direction of said second quarter-wave plate is at 45 degrees to the polarized light transmitting direction of said polarizing plate disposed between the ocular optical system and the observer'"'"'s eyeball.

7. An image display apparatus according to claim 5, further comprising a quarter-wave plate disposed in an optical path extending from said half-mirror to said reflecting mirror so that a crystallographic axis direction of said quarter-wave plate is at 45 degrees to a polarized light transmitting direction of said polarizing plate disposed between the ocular optical system and the observer'"'"'s eyeball.

8. An image display apparatus according to claim 5, wherein said polarizing plate is disposed so that a polarized light transmitting direction of said polarizing plate coincides with a direction of polarization of light from said display device disposed between the ocular optical system and the observer'"'"'s eyeball.

9. An image display apparatus according to claim 5, wherein said image display means is a liquid crystal display device including an illuminating device, a liquid crystal, and a polarizing plate for said liquid crystal display device provided only on a side of said liquid crystal display device which is closer to said illuminating device, said polarizing plate disposed between the ocular optical system and the observer'"'"'s eyeball being disposed so that a polarized light transmitting direction of said polarizing plate disposed between the ocular optical system and the observer'"'"'s eyeball coincides with or perpendicularly intersects a polarized light transmitting direction of said polarizing plate for said liquid crystal display device.

10. An image display apparatus according to claim 5, wherein said ocular optical display system comprises a glass prism having said half-mirror and said reflecting mirror integrally formed therein.

11. An image display apparatus according to claim 10, wherein said half-mirror is a mirror which splits light into transmitted light and reflected light independently of polarization.

12. An image display apparatus according to claim 5, wherein said half-mirror is a half-mirror plate.

3. An image display apparatus comprising:

an image display means for forming a polarized light image; and

an ocular optical system for leading said polarized light image to an observer'"'"'s eyeball,

wherein said ocular optical system has a reflecting mirror for reflecting said image, and further has at least the following;

a polarizing plate disposed between said ocular optical system and said observer'"'"'s eyeball;

a polarizing plate disposed to face opposite to said observer'"'"'s eyeball across said ocular optical system; and

a polarizing plate disposed in said image display means.