HMD device with imaging optics comprising an aspheric surface

• US 20050046954A1
• Filed: 09/03/2004
• Published: 03/03/2005
• Est. Priority Date: 09/03/2003
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT AG (Carl-Zeiss-Stiftung)
• Original Assignee: CARL Zeiss SMT AG (Carl-Zeiss-Stiftung)
• Inventors: Achtner, Bertram
• Granted Patent: US 6,903,875 B2
• Time in Patent Office: Days
• US Class Current: 359/630
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 3/04 with continuous faces that are rotationally symmetrical but deviate from a true sphere , e.g. so called "aspheric" lenses

Abstract

An HMD device is provided, comprising an image element for generating an image and imaging optics projecting the image such that it is perceivable by a user wearing said HMD device, wherein said imaging optics comprise a first optical group including a first lens, which has negative refractive power, and a second lens, which has positive refractive power, a deflecting element arranged following the first optical group as well as a second optical group following the deflecting element, said second optical group comprising a third lens, and wherein, for correction of astigmatism and distortion, at least one surface of the first and second lenses is aspheric and, for correction of the spherical aberration, at least one surface of the third lens is aspheric.

Claims

1. An HMD device comprising:

an image element to generate an image;

imaging optics projecting the image such that it is perceivable by a user wearing said HMD device, wherein said imaging optics comprise a first optical group including a first lens, having negative refractive power, and a second lens, having positive refractive power and a deflecting element arranged following the first optical group; and

a second optical group following the deflecting element, said second optical group comprising a third lens, wherein, for correction of astigmatism and distortion, at least one surface of the first and second lenses is aspheric and, for correction of the spherical aberration, at least one surface of the third lens is aspheric.

2. The HMD device as claimed in claim 1, wherein, for correction of curvature of field, the first lens is located closer to an image plane in which the generated image lies than is the second lens and the first lens is further located closer to said image plane than to the deflecting element.

3. The HMD device as claimed in claim 1, wherein, to correct transverse chromatic aberration, the first lens is formed of a first material having a higher dispersion than a second material from which the second lens is formed.

4. The HMD device as claimed in claim 2, wherein, to correct transverse chromatic aberration, the first lens is formed of a first material having a higher dispersion than a second material from which the second lens is formed.

5. The HMD device as claimed in claim 1, wherein, to correct longitudinal chromatic aberration, the second optical group comprises a diffractive surface.

6. The HMD device as claimed in claim 5, wherein the diffractive surface is located on the aspheric surface of the third lens.

7. The HMD device as claimed in claim 5, wherein the diffractive surface is a planar surface.

8. The HMD device as claimed in claim 1, wherein, to correct for longitudinal chromatic aberration, the second optical group comprises an achromat.

9. The HMD device as claimed in claim 1, wherein, to correction for astigmatism and distortion, one surface of the first lens and one surface of the second lens is aspherically designed.

10. The HMD device as claimed in claim 1, wherein the second lens and the third lens are identically designed.

11. The HMD device as claimed in claim 1, wherein the deflecting element alters the optical path about seventy degrees to about one hundred ten degrees.

12. The HMD device as claimed in claim 1, wherein the deflecting element alters of the optical path about ninety degrees.

13. The HMD device as claimed in claim 1, wherein the deflecting element alters of the optical path by a single reflection.

14. The HMD device as claimed in claim 1, wherein the two optical groups have optical elements having multiple optical surfaces and each optical element has an optical center and the imaging optics have an optical axis and all of the optical surfaces have rotational symmetry and all of the optical centers coincide with the optical axis of the imaging optics.

15. The HMD device as claimed in claim 5, in which the diffracting surface has a kinoform profile.

16. The HMD device as claimed in claim 1, in which the imaging optics has a focal length f, the first lens has a focal length f₁, a second lens has a focal length f₂, and

−

1.2 f<

f₁<

−

0.3 f

and

0.6 f<

f₂<

1.5 f.

17. The HMD device as claimed in claim 16, in which second optical group has a focal length f₃ and 0.6 f<

f₃<

1.7 f.

18. The HMD device as claimed in claim 1, in which the HMD device has a structural length L from the image element to an exit pupil P as measured along an optical axis and the HMD device has a structural length L₁ from the image element to a vertex of the deflecting element and structural length L₂ from the vertex of the deflecting element to the exit pupil P and

0.6 f<

L₁<

1.2 f.

and

0.8 f<

L₂<

1.5 f

and

1.2 f<

L<

2.6 f.