Optical element and compound display apparatus using the same

• US 6,646,811 B2
• Filed: 04/19/2001
• Issued: 11/11/2003
• Est. Priority Date: 03/01/2001
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Inoguchi, Kazutaka
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Dinh, Jack
• Application Number:
  US09/837,301
• Publication Number:
  US 20020163734A1
• Time in Patent Office: 936 Days
• Field of Search: 359/619, 359/626, 359/630, 359/629, 359/637, 359/639, 359/631, 359/676, 359/720, 359/633, 359/728, 250/494.1, 345/6, 345/7, 345/8
• US Class Current: 359/631
• CPC Class Codes: G02B 17/0812 off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry
• CPC Class Codes: G02B 17/0816 off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements
• CPC Class Codes: G02B 17/086 wherein the system is made of a single block of optical material, e.g. solid catadioptric systems
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• 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 27/1066 for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence

Abstract

The present invention has as its object to provide a thin type optical system which enables both of image information displayed on display means such as a liquid crystal display to be observed and image information of which image is substantially equal to the image observed via therethrough and which is taken by image pickup means and a compound display apparatus using such optical system. For this object, the optical element according to the present invention is an optical element having on the same medium an incidence surface, an emergence surface and a plurality of eccentric reflecting surfaces eccentric relative to a reference ray Ri and having power, at least one of the plurality of eccentric reflecting surfaces being a dual purpose surface used as a transmitting surface and reflecting surface, wherein a beam incident from the incidence surface is reflected by the plurality of eccentric reflecting surfaces to thereby fold an optical path and is caused to emerge from the emergence surface, and is characterized in that the meridional section composite power of the optical element is negative.

Claims

1. An optical element comprising:

an incidence surface for a beam;

an emergence surface for the beam;

a plurality of eccentric reflecting surfaces each of which is eccentric relative to a reference ray Ri and has power, which from an optical path for guiding the beam incident at said incidence surface to said emergence surface and at least one of which is rotation-asymmetrical,

wherein local meridional section focal length f_ypout and local sagittal section composite focal length f_xpout of said emergence surface and meridional section composite focal length f_yp and sagittal section focal length f_xp satisfy

2. An optical element according to claim 1, wherein meridional section composite power is negative.

3. An optical element according to claim 2,

wherein all of the incidence surfaces and the emergence surfaces and the eccentric reflecting surfaces are rotation-asymmetrical surface.

4. An optical clement according to claim 1,

wherein at least one of said plurality of eccentric reflecting surfaces is a dual purpose surface used as a transmitting surface and reflecting surface.

5. A compound lens unit comprising:

at least one optical member having two opposite optical surfaces, wherein one optical surface is rotation asymmetrical and the other is rotation symmetrical; and

a rotational symmetrical lens,

wherein all optical axes of symmetrical optical surfaces of said optical member and said rotational symmetrical lens are substantially coincident.

6. A compound lens unit according to claim 5, wherein design is made such that the local meridional section focal length f_yl and local sagittal section focal length f_xl of said rotation-asymmetrical surface and the meridional section composite focal length f_yg and sagittal section composite focal length f_xg of said compound lens unit satisfy

7. An image pickup optical system comprising:

an optical element comprising;

an incidence surface for a beam,

an emergence surface for the beam, and

a plurality of eccentric reflecting surfaces each of which is eccentric relative to a reference ray Ri and has power, which form an optical path for guiding the beam incident at said incidence surface to said emergence surface,

wherein meridional section composite power is negative; and

compound lens unit according to claim 5,

wherein the light from the external world said is imaged on an image pickup element using said optical element and said compound lens unit.

8. An image pickup optical system according to claim 7, wherein design is made such that when the meridional section composite focal length of the entire image pickup optical system is defined as f_y and the sagittal section composite focal length thereof is defined as f_x and the meridional section composite focal length of said optical element is defined as f_yp and the sagittal section composite focal length thereof is defined as f_xp'"'"'

9. An image pickup optical system according to claim 7, wherein deflecting means for bending the optical path in a direction differing from the direction in which the optical path of said optical element is folded is provided between said stop and said compound lens unit.

10. A compound display apparatus comprising:

an image pickup optical system according to claim 7;

an image pickup element;

display means; and

a display optical system comprising;

a second optical element comprising

an incidence surface for a beam,

an emergence surface for the beam, and

a plurality of eccentric reflecting surfaces

each of which is eccentric relative to a display

reference ray Rd and has power, which form an optical

path for guiding the beam incident at said

incidence surface to said emergence surface,

wherein one of the eccentric reflecting surfaces of the optical element of said image pickup optical system and one of the eccentric reflecting surfaces of said second optical element have substantially the same shape and use the front and back surfaces of an optical path separating surface, and said optical path separating surface is a half-transmitting reflecting surface to form a see-through optical system,

wherein a see-through reference ray Rs, passing through the center of the external world and the center of an exit pupil of the see-through optical system, and the display reference ray Rd substantially coincides with the optical axis of the eyeball, and the see-through reference ray Rs and a reference ray Ri of the image pickup optical system substantially coincide with the optical axis of the external world.

11. An image pickup optical system comprising:

an optical element comprising;

an incidence surface for a beam,

an emergence surface for the beam, and

a plurality of eccentric reflecting surfaces each of which is eccentric relative to a reference ray Ri and has power, which form an optical path for guiding the beam incident at said incidence surface to said emergence surface and at least one of which is rotation-asymmetrical,

wherein local meridional section focal length f_ypout and local sagittal section focal length f_xpout of said emergence surface and meridional section composite focal length f_yp and sagittal section composite focal length f_xp satisfy,

12. A compound display apparatus comprising:

an image pickup optical system according to claim 11;

an image pickup element;

display means; and

a display optical system comprising;

a second optical element comprising

an incidence surface for a beam,

an emergence surface for the beam,

a plurality of eccentric reflecting surfaces each of which is eccentric relative to a display reference ray Rd and has power, which form an optical path (for guiding said beam incident at said incidence surface to said emergence surface,

wherein one of the eccentric reflecting surfaces of the optical element of said image pickup optical system and one of the eccentric reflecting surfaces of said second optical element have substantially the same shape and use the front and back surfaces of an optical path separating surface, and said optical path separating surface is a half transmitting reflecting surface to form a see-through optical system,

wherein a see-through reference ray Rs, passing through the center of the external world and the center of an exit pupil of said see-through optical system, and said display reference ray Rd substantially coincide with the optical axis of the eyeball, and said see-through reference ray Rs and a reference ray Ri of the image pickup optical system substantially coincides with the optical axis of the external world.

13. A compound display apparatus according to claim 10 or 12, wherein design is made such that when the distance from the position of the evolved entrance pupil when the entrance pupil of said image pick up optical system is evolved on the visual axis to the position of the exit pupil of said display optical system is defined as Dpp and the distance from the emergence surface of said display optical system to the exit pupil of said display optical system is defined as er,

14. An image pickup optical system according to claim 7 or claim 11,

wherein at least one of said plurality of eccentric reflecting surfaces is a dual purpose surface used as a transmitting surface and reflecting surface.

15. A compound display apparatus

a display optical system for directing a beam from display means to an observer'"'"'s eyeball;

and

an image pickup optical system for imaging a beam from the external world on an image pickup element, comprising;

an optical element comprising

an incidence surface for a beam,

an emergence surface for the beam, and

a plurality of eccentric reflecting surfaces each of which is eccentric relative to a reference ray Ri and has power, which form an optical path for guiding said beam incident at said incidence surface to said emergence surface,

wherein meridional section composite power of the optical element is negative, and

wherein the optical axis of the external world in said image pickup optical system substantially coincides with an eyeball optical axis or a virtual eyeball optical axis extended from the eyeball optical axis in said display optical system.

16. A compound display apparatus according to claim 15, wherein said image pickup optical system has a compound lens unit having at least one rotation-asymmetrical lens of which the opposite surfaces comprise a rotation-asymmetrical surface and a rotation-symmetrical surface, respectively, and a plurality of rotation-symmetrical lenses, wherein all of the optical axis of the rotation-symmetrical surface of said rotation-asymmetrical lens and the optical axes of said rotation-symmetrical lenses are substantially coincident with one another, and the beam from the external world is passed through said optical element, and thereafter is directed onto said image pickup element by said compound lens unit.

17. A compound display apparatus according to claim 16, wherein design is made such that the local meridional section focal length f_ypout and local sagittal section focal length f_xpout of the emergence surface of said optical element and the meridional section composite focal length f_yp and sagittal section composite focal length f_xp of said optical element satisfy

18. A compound display apparatus according to claim 17, wherein design is made such that the local meridional section focal length f_yl and local sagittal section focal length f_xl of the rotation-asymmetrical surface of said compound lens unit and the meridional section composite focal length f_yg and sagittal section composite focal length f_xg of said compound lens unit safety

19. A compound display apparatus according to claim 18, wherein design is made such that when the meridional section composite focal length of the entire image pickup optical system is defined as f_y and the sagittal section composite focal length thereof is defined as f_x and the meridional section composite focal length of said optical element is defined as fyp and the sagittal section composite focal length thereof is defined as f_xp'"'"'

20. A compound display apparatus according to claim 19, wherein design is made such that when the distance from the position of the evolved entrance pupil when the entrance pupil of said image pickup optical system is evolved on the visual axis to the position of the exit pupil of said display optical system is defined as Dpp and the distance from the emergence surface of said display optical system to the exit pupil of said display optical system is defined as er,