TWI416165B - Super-wide-angle lens - Google Patents

Abstract

The present invention relates to a super-wide-angle lens. The super-wide-angle lens includes, in this order from the object side to the image side of the super-wide-angle lens, a first lens group, a second lends group, and an imaging surface. The first lens group has negative refractive power. The second lens group has positive refractive power. The first lens group includes a first spherical lens, a second spherical lens, and a third spherical lens arranged in this order from the object side to the image side along the optical axis of the super-wide-angle lens. The first spherical lens includes a first object surface and a first image surface. The wide lens satisfies the following formula: 8.9 < D/F0 < 9.9, wherein, D is the distance along the optical axis between an apex point of the first object surface and the imaging surface, F0 is the focal length of the super-wide-angle lens.

Description

Ultra wide-angle lens

The invention relates to an ultra wide angle lens.

The angle of view of a conventional super wide-angle lens for a vehicle is above 90 degrees, resulting in large distortion and distortion of the image. In order to overcome the aberrations such as distortion, the existing super wide-angle lens adopts a larger number of lens groups, resulting in a generally larger thickness of the super wide-angle lens.

In view of this, it is necessary to provide a super wide-angle lens having a small thickness.

An ultra wide-angle lens includes, in order from its object end to the image end, a first lens group having a negative power, a second lens group having a positive power, and an imaging surface in the optical axis direction thereof. The first lens group includes a first spherical lens, a second spherical lens and a third spherical lens in this optical axis direction from the object end to the image end. The first spherical lens includes a first object end surface and a first image end surface. The super wide-angle lens satisfies the following conditional formula: 8.9<D/F0<9.9

Where D is the distance between the vertex of the first object end surface and the imaging surface on the optical axis; F0 is the effective focal length of the super wide-angle lens.

Compared with the prior art, the super wide-angle lens of the present invention not only has a large angle of view And the thickness along the optical axis direction is thinned.

100‧‧‧Super wide-angle lens

10‧‧‧First lens group

11‧‧‧First spherical lens

S1‧‧‧ first side surface

S2‧‧‧ first image side surface

12‧‧‧Second spherical lens

S3‧‧‧Second side surface

S4‧‧‧Second image side surface

13‧‧‧ Third spherical lens

S5‧‧‧ third side surface

S6‧‧‧ third image side surface

20‧‧‧second lens group

21‧‧‧fourth spherical lens

S7‧‧‧ fourth side surface

S8‧‧‧ fourth image side surface

22‧‧‧ fifth spherical lens

S9‧‧‧ fifth side surface

S10‧‧‧ Fifth image side surface

23‧‧‧ Sixth spherical lens

S11‧‧‧ sixth side surface

S12‧‧‧ sixth image side surface

S13‧‧‧ seventh side surface

S14‧‧‧ seventh image side surface

40‧‧‧Filter

51‧‧‧ imaging surface

60‧‧‧Light

1 is a schematic structural view of a super wide-angle lens of the present invention.

2 is a spherical aberration diagram of the super wide-angle lens of FIG. 1.

3 is a field curvature diagram of the super wide-angle lens of FIG. 1.

4 is a distortion diagram of the super wide-angle lens of FIG. 1.

The invention will be further described in detail below with reference to the accompanying drawings.

Please refer to FIG. 1 , which is a schematic structural diagram of an ultra wide-angle lens 100 according to an embodiment of the present invention. The super wide-angle lens 100 includes a first lens group 10 having a negative refractive power, a second lens group 20 having a positive refractive power, and a filter 40 sequentially along the optical axis direction thereof from the object end to the image end. And an imaging surface 51. When the image is taken, the light is first formed on the imaging surface 51 through the first lens group 10, the second lens group 20, and the filter 40.

The first lens group 10 includes a first spherical lens 11, a second spherical lens 12 and a third spherical lens 13 in order from the object end to the image end. The first spherical lens 11 includes a first object end surface S1 and a first image end surface S2. The second spherical lens 12 includes a second object end surface S3 and a second image end surface S4. The third spherical lens 13 includes a third object end surface S5 and a third image end surface S6.

The second lens group 20 includes a fourth spherical lens 21, a fifth spherical lens 22, and a sixth spherical lens 23 in order from the object end to the image end. The fourth spherical lens 21 includes a fourth object end surface S7 and a fourth image end surface S8. The fifth spherical lens 22 The fifth object end surface S9 and the fifth image end surface S10 are included. The sixth spherical lens 23 includes a sixth object end surface S11 and a sixth image end surface S12. The fifth image end surface S10 and the sixth object end surface S11 are glued and fixed.

The super wide-angle lens 100 further includes an aperture stop 60 disposed between the first lens group 10 and the second lens group 20 to limit the light flux entering the second lens group 20 through the first lens group 10. And the light cone after passing through the second lens group 20 is more symmetrical, so that the coma of the super wide-angle lens 100 is corrected. In the embodiment, the aperture 60 is a black rubber ring, and the aperture 60 is attached to the fourth object end surface S7.

The super wide-angle lens 100 further includes a filter 40 disposed between the second lens group 20 and the imaging surface 51. The filter 40 includes a seventh object end surface S13 and a seventh image end surface S14.

The super wide-angle lens 100 satisfies the following conditional formula: (1) 8.9 < D / F0 < 9.9

Where D is the distance between the vertex of the first object end surface S1 and the imaging surface 51 on the optical axis; F0 is the effective focal length of the super wide-angle lens 100; this conditional expression is used to balance the super wide-angle lens 100 The total length and aberration along its optical axis. If the total length of the super wide-angle lens 100 along its optical axis direction is too long, the principle of miniaturization cannot be satisfied; if the total length of the super wide-angle lens 100 along its optical axis direction is too short, the existing optical power cannot be obtained. Good image quality is achieved under distribution.

Preferably, the super wide-angle lens 100 also needs to satisfy the following conditional formula: (2) 0.8<F0/|FG1|<0.9

Wherein F0 is the effective focal length of the super wide-angle lens 100; FG1 is the effective focal length of the first lens group 10; this conditional expression limits the effective focal length of the first lens group 10. If the value is less than 0.8, the effective focal length of the first lens group 10 is too long, resulting in the optical power of the first lens group 10 being too small, and it is difficult to correct the field curvature of the light beam. If it is greater than 0.9, the The effective focal length of the first lens group 10 is too short, which may cause the power of the first lens group 10 to be too large, so that the second lens group 20 cannot sufficiently correct the lateral and longitudinal chromatic aberrations.

Preferably, the super wide-angle lens 100 also satisfies the following condition (3) 3.5<|FL2/F0|<4.5

Wherein F0 is the effective focal length of the super wide-angle lens 100; FL2 is the effective focal length of the second spherical lens 12; this conditional expression limits the effective focal length of the second spherical lens 12. If the value is less than 3.5, the effective focal length of the second spherical lens 12 is too short, so that the optical power of the second spherical lens 12 is too long, so that the spherical aberration caused by the first lens group 10 is difficult to be corrected. 4.5, the effective focal length of the second spherical lens 12 is too long, resulting in the optical power of the second spherical lens 12 being too small, so that the axial chromatic aberration of the super wide-angle lens 100 will not be sufficiently compensated.

Further, the super wide-angle lens 100 also needs to satisfy the following conditional formula: (4) ν 5-ν 6> 35

Wherein ν 5 is the Abbe number of the fifth spherical lens; ν 6 is the Abbe number of the sixth spherical lens; and the super wide-angle lens 100 is fixed by the glue in the second lens group 20 The fifth spherical lens 22 and the sixth spherical lens 23 can effectively correct the axial chromatic aberration of the super wide-angle lens 100, and the overall performance of the super wide-angle lens 100 can be optimized.

The optical elements of the super wide-angle lens 100 satisfy the conditions of Table 1. In the following list (1), the optical surface numbers (Surface #) sequentially numbered from the object end to the image end are listed, R is the radius of curvature of the optical surface of each lens, and D is the axis corresponding to the surface of the latter surface. The distance (the length of the two surfaces intercepted by the optical axis), Nd is the refractive index of the corresponding lens group pair d light (wavelength is 587 nm), and Vd is the abbe number of the d light in the corresponding lens group, f is The effective focal length of the super wide-angle lens 100; F number is the aperture number of the super wide-angle lens 100; 2 ω is the angle of view of the super wide-angle lens 100. In the present embodiment, f=1.56 mm, F number=2.5, 2ω=163o

The aberration, curvature of field, and distortion of the super wide-angle lens 100 of the present embodiment are as shown in FIGS. 2 to 4, respectively. In Fig. 2, for the g line (wavelength value 436 nm), the F line (wavelength value 486 nm), the e line (wavelength value 546 nm), the d line (wavelength value 588 nm), and the C line (wavelength value 656 nm), respectively, The aberration curve. In general, the super wide-angle lens 100 of the present embodiment controls the aberration value generated for visible light (wavelength ranging from 400 nm to 700 nm) to be within the range of (-0.2 mm, 0.2 mm). In Fig. 3, the curves T and S are the tangential field curvature characteristic curve and the sagittal field curvature characteristic curve, respectively. It can be seen that the meridional curvature value and the sagittal curvature value are controlled within the range of (-0.05 mm, 0.05 mm). In Fig. 4, the curve dis is a distortion characteristic curve. As can be seen from the figure, the distortion is controlled within the range of (-50%, 50%). It can be seen that the aberration, curvature of field, and distortion of the super wide-angle lens 100 can be controlled (corrected) in a small range.

Compared with the prior art, the super wide-angle lens of the present invention not only has a large angle of view but also has a thin thickness along the optical axis direction thereof.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧Super wide-angle lens

10‧‧‧First lens group

11‧‧‧First spherical lens

S1‧‧‧ first side surface

S2‧‧‧ first image side surface

12‧‧‧Second spherical lens

S3‧‧‧Second side surface

S4‧‧‧Second image side surface

13‧‧‧ Third spherical lens

S5‧‧‧ third side surface

S6‧‧‧ third image side surface

20‧‧‧second lens group

21‧‧‧fourth spherical lens

S7‧‧‧ fourth side surface

S8‧‧‧ fourth image side surface

22‧‧‧ fifth spherical lens

S9‧‧‧ fifth side surface

S10‧‧‧ Fifth image side surface

23‧‧‧ Sixth spherical lens

S11‧‧‧ sixth side surface

S12‧‧‧ sixth image side surface

S13‧‧‧ seventh side surface

S14‧‧‧ seventh image side surface

40‧‧‧Filter

51‧‧‧ imaging surface

60‧‧‧Light

Claims (8)

An ultra wide-angle lens comprising, in order from its object end to the image end, a first lens group having a negative power, a second lens group having a positive power, and an imaging surface; the first lens group a first spherical lens, a second spherical lens and a third spherical lens arranged in sequence from the object end to the image end in the optical axis direction; the first spherical lens includes a first object end surface and a first image end The super wide-angle lens satisfies the following conditional formula: 8.9 < D / F0 < 9.9 where D is the distance between the vertex of the first object end surface and the imaging surface on the optical axis; F0 is the super The effective focal length of the wide-angle lens. The super wide-angle lens according to claim 1, wherein the super wide-angle lens further satisfies the following conditional formula: 0.8 < F0 / | FG1 | < 0.9, wherein FG1 is an effective focal length of the first lens group. The super wide-angle lens according to claim 1, wherein the super wide-angle lens further satisfies the following conditional formula: 3.5<|FL2/F0|<4.5, wherein FL2 is an effective focal length of the second spherical lens. The super wide-angle lens according to claim 1, wherein the second lens group includes a fourth spherical lens, a fifth spherical lens and a sixth spherical surface in order from the object end to the image end in the optical axis direction. lens. The ultra wide-angle lens of claim 4, wherein the super wide-angle lens The head also satisfies the following conditional expression: ν 5-ν 6>35 where ν 5 is the Abbe number of the fifth spherical lens; ν 6 is the Abbe number of the sixth spherical lens. The ultra wide-angle lens of claim 4, wherein the fourth spherical lens includes a fourth object end surface, the super wide-angle lens further includes an aperture, and the aperture is attached to the fourth On the surface of the object. The super wide-angle lens of claim 4, wherein the fifth spherical lens includes a fifth image end surface, and the sixth spherical lens includes a sixth object end surface, the fifth image end surface The surface of the sixth object end is glued and fixed. The super wide-angle lens of claim 1, wherein the super wide-angle lens further comprises a filter, the filter being located on an object side of the imaging surface.