Wide-angle camera for head-mounted device, and head-mounted device

1. A wide-angle camera for a head-mounted device, comprising:

a casing,

a biconvex plus lens, and

a biconcave minus lens,

wherein the biconvex plus lens and the biconcave minus lens are arranged in parallel in the casing and the biconcave minus lens is closer to an object space,

wherein the biconcave minus lens is able to move along an axis of the casing to adjust a distance to the biconvex plus lens;

wherein a focal power of a zooming system of the wide-angle camera is set to be a range from −0.005 to 0.005, and thus the biconvex plus lens is stationary in the wide-angle camera, and a movement of the biconcave minus lens enables the wide-angle camera to be suitable for users having nearsightedness between 0 and 500 degrees and users having farsightedness between 0 and 500 degrees.

2. The wide-angle camera for a head-mounted device according to claim 1 , wherein the biconvex plus lens comprises a first surface that is convex toward the object space, and a second surface that has a flat edge and a center position that is convex toward an image space,

wherein the biconcave minus lens comprises a third surface that is concave toward the image space, and a fourth surface that has a flat edge and a center position that is concave toward the object space, and

wherein lens surfaces of the biconvex plus lens and the biconcave minus lens are both aspheric surfaces.

3. The wide-angle camera for a head-mounted device according to claim 2 , wherein the third surface is an aspheric surface having an indefinitely large curvature radius.

4. The wide-angle camera for a head-mounted device according to claim 2 , wherein surface shapes of the first surface, the second surface, the third surface and the fourth surface follow a formula:

Z

=

cY

2

1

+

1

-

(

1

+

k

)

⁢

c

2

⁢

Y

2

+

∑

i

=

1

N

⁢

⁢

α

i

⁢

Y

2

⁢

i

wherein, Z is a coordinate in an optical axis direction, Y is a radial coordinate in the unit of a lens length unit, c is a curvature, k is a conical coefficient, α i is a coefficient of each high order term, 2i is an aspheric high order power, and N is a natural number.

5. The wide-angle camera for a head-mounted device according to claim 1 , wherein the biconvex plus lens has a refractive index ranging from 1.45-1.70, and a chromatic dispersion ranging from 50-75.

6. The wide-angle camera for a head-mounted device according to claim 5 , wherein the biconvex plus lens is made of a plastic material, with n1=1.531160 and v1=56.04, wherein n1 is a refractive index, and v1 is a chromatic dispersion.

7. The wide-angle camera for a head-mounted device according to claim 1 , wherein the biconcave minus lens has a refractive index ranging from 1.45-1.75, and a chromatic dispersion ranging from 25-40.

8. The wide-angle camera for a head-mounted device according to claim 7 , wherein the biconcave minus lens is made of a plastic material, with n1=1.5585470 and v1=29.91, wherein n1 is a refractive index, and v1 is a chromatic dispersion.

9. The wide-angle camera for a head-mounted device according to claim 1 , wherein the focal power of the zooming system of the wide-angle camera is calculated in the following chromatic difference correction formula:

c

=

∑

⁢

φ

ν

=

(

φ

⁢

⁢

1

ν

⁢

⁢

1

+

φ

⁢

⁢

2

ν2

)

wherein, c is a chromatic difference coefficient, ν is a dispersion coefficient of the system, φ is the focal power of the system, ν1 and ν2 are dispersion coefficients of the respective lenses, and φ1 and φ2 are focal powers of the respective lenses.

10. A head-mounted device, comprising a wide-angle camera for a head-mounted device, the wide-angle camera for a head-mounted device, comprising:

a casing,

a biconvex plus lens, and

a biconcave minus lens,

wherein the biconvex plus lens and the biconcave minus lens are arranged in parallel in the casing and the biconcave minus lens is closer to an object space,

wherein the biconcave minus lens is able to move along an axis of the casing to adjust a distance to the biconvex plus lens;

wherein a focal power of a zooming system of the wide-angle camera is set to be a range from −0.005 to 0.005, and thus the biconvex plus lens is stationary in the wide-angle camera, and a movement of the biconcave minus lens enables the wide-angle camera to be suitable for users having nearsightedness between 0 and 500 degrees and users having farsightedness between 0 and 500 degrees.

11. The head-mounted device according to claim 10 , wherein the biconvex plus lens comprises a first surface that is convex toward the object space, and a second surface that has a flat edge and a center position that is convex toward an image space,

wherein the biconcave minus lens comprises a third surface that is concave toward the image space, and a fourth surface that has a flat edge and a center position that is concave toward the object space, and

wherein lens surfaces of the biconvex plus lens and the biconcave minus lens are both aspheric surfaces.

12. The head-mounted device according to claim 11 , wherein the third surface is an aspheric surface having an indefinitely large curvature radius.

13. The head-mounted device according to claim 11 , wherein surface shapes of the first surface, the second surface, the third surface and the fourth surface follow a formula:

Z

=

cY

2

1

+

1

-

(

1

+

k

)

⁢

c

2

⁢

Y

2

+

∑

i

=

1

N

⁢

⁢

α

i

⁢

Y

2

⁢

i

wherein, Z is a coordinate in an optical axis direction, Y is a radial coordinate in the unit of a lens length unit, c is a curvature, k is a conical coefficient, α i is a coefficient of each high order term, 2i is an aspheric high order power, and N is a natural number.

14. The head-mounted device according to claim 10 , wherein the biconvex plus lens has a refractive index ranging from 1.45-1.70, and a chromatic dispersion ranging from 50-75.

15. The head-mounted device according to claim 14 , wherein the biconvex plus lens is made of a plastic material, with n1=1.531160 and v1=56.04, wherein n1 is a refractive index, and v1 is a chromatic dispersion.

16. The head-mounted device according to claim 10 , wherein the biconcave minus lens has a refractive index ranging from 1.45-1.75, and a chromatic dispersion ranging from 25-40.

17. The head-mounted device according to claim 16 , wherein the biconcave minus lens is made of a plastic material, with n1=1.5585470 and v1=29.91, wherein n1 is a refractive index, and v1 is a chromatic dispersion.

18. The head-mounted device according to claim 10 , wherein the focal power of the zooming system of the wide-angle camera is calculated in the following chromatic difference correction formula:

c

=

∑

⁢

φ

ν

=

(

φ

⁢

⁢

1

ν

⁢

⁢

1

+

φ

⁢

⁢

2

ν2

)

wherein, c is a chromatic difference coefficient, ν is a dispersion coefficient of the system, φ is the focal power of the system, ν1 and ν2 are dispersion coefficients of the respective lenses, and φ1 and φ2 are focal powers of the respective lenses.