An ultra-wide-angle cat-eye lens

Abstract

The present invention discloses an ultra-wide-angle cat's eye lens, which includes a first lens element, a second lens element, a third lens element, an aperture, a fourth lens element and a fifth lens element from the object side to the image side in sequence, and is characterized in that the first lens element is a meniscus lens with negative focal length convex to the object side; the second lens element is a biconcave lens with negative focal length; the third lens element is a meniscus lens with positive focal length convex to the image side; the fourth lens element is a biconcave lens with negative focal length; the fifth lens element is a plano-convex lens with positive focal length convex to the image side; wherein the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element are all glass spherical mirrors. The present invention adopts a spherical design, has good process performance and low material cost; the five lens elements are subjected to the best optical design to correct off-axis aberrations and compensate chromatic aberrations, so as to obtain an ultra-wide-angle cat's eye lens with high brightness and high MTF value.

Description

Technical Field

[0001] The present invention relates to the technical field of cat's eye lenses, and more particularly to an ultra-wide-angle cat's eye lens. Background Art

[0002] With the development of society, more and more people pay more attention to home security. For the cat's eye lens market, cat's eye lenses with ultra-wide angle, high brightness and good observation clarity have become the mainstream development trend.

[0003] Therefore, how to provide an ultra-wide-angle cat-eye lens that can meet the above requirements is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0004] In view of this, an object of the present invention is to provide an ultra-wide-angle cat's eye lens, which has the characteristics of ultra-wide angle, good observation effect, high brightness and high MTF value.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An ultra-wide-angle cat-eye lens, which includes a first lens element, a second lens element, a third lens element, an aperture, a fourth lens element and a fifth lens element in order from the object side to the image side, characterized in that:

[0007] The first lens element is a meniscus lens with negative optical power convex to the object side;

[0008] The second lens element is a biconcave lens having negative optical power;

[0009] The third lens element is a meniscus lens with positive power convex to the image side;

[0010] The fourth lens element is a biconcave lens with negative optical power;

[0011] The fifth lens element is a plano-convex lens with positive refractive power and convex toward the image side;

[0012] Wherein, the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element are all glass spherical mirrors.

[0013] Preferably, in the above-mentioned super wide-angle cat's eye lens, the first lens element satisfies: 1.70≤Nd1≤1.78; 52.62≤Vd1≤52.72.

[0014] Preferably, in the above-mentioned super wide-angle cat's eye lens, the second lens element satisfies: 1.73≤Nd2≤1.80; 49.56≤Vd2≤49.65.

[0015] Preferably, in the above-mentioned super wide-angle cat's eye lens, the third lens element satisfies: 1.76≤Nd3≤1.85; 25.43≤Vd3≤25.52.

[0016] Preferably, in the above-mentioned super wide-angle cat's eye lens, the fourth lens element satisfies: 1.80≤Nd4≤1.88; 23.75≤Vd4≤23.83.

[0017] Preferably, in the above-mentioned super wide-angle cat's eye lens, the fifth lens element satisfies: 1.68≤Nd5≤1.75; 53.82≤Vd5≤53.90.

[0018] Preferably, in the above-mentioned ultra-wide-angle cat-eye lens, the lens satisfies the following conditions: the focal length satisfies EFL=10.3 mm; the total length of the lens satisfies TTL=90.1±0.3 mm; and the field of view of the lens satisfies DFOV=180°.

[0019] Preferably, in the above-mentioned ultra-wide-angle cat-eye lens, the lens is suitable for doors with a thickness of 65-90 mm.

[0020] It can be seen from the above technical solution that, compared with the prior art, the present invention adopts a spherical design with good process performance and low material cost; the five lens elements are designed with the best optical design to correct off-axis aberrations and compensate for chromatic aberrations, thereby obtaining an ultra-wide-angle cat's eye lens with high brightness and high MTF value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 The accompanying drawing is a schematic diagram of the specific structure of the lens of the present invention.

[0023] Figure 2 The accompanying drawing is a light path diagram of the lens of the present invention.

[0024] Figure 3 The attached drawing is a ray fan diagram of the lens of the present invention.

[0025] Figure 4 The attached drawing is a spot diagram of the lens of the present invention.

[0026] Figure 5 The accompanying drawing is a MTF resolution curve diagram of the lens of the present invention.

[0027] Figure 6The attached figure is a chromatic aberration curve diagram of the lens of the present invention.

[0028] Figure 7 The attached figure is a relative brightness curve diagram of the lens of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Embodiment 1:

[0031] An ultra-wide-angle cat's eye lens, which includes a first lens element 1, a second lens element 2, a third lens element 3, an aperture, a fourth lens element 4 and a fifth lens element 5 in order from the object side to the image side, and is characterized in that:

[0032] The first lens element is a meniscus lens with negative optical power convex to the object side;

[0033] The second lens element is a biconcave lens having negative optical power;

[0034] The third lens element is a meniscus lens with positive power convex to the image side;

[0035] The fourth lens element is a biconcave lens with negative optical power;

[0036] The fifth lens element is a plano-convex lens with positive refractive power and convex toward the image side;

[0037] Wherein, the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element are all glass spherical mirrors.

[0038] Preferably, the first lens element Nd1=1.725; Vd1=52.65.

[0039] Preferably, the second lens element Nd2=1.745; Vd2=49.580.

[0040] Preferably, the third lens element Nd3=1.785; Vd3=25.455.

[0041] Preferably, the fourth lens element Nd4=1.835; Vd4=23.775.

[0042] Preferably, the fifth lens element Nd5=1.695; Vd5=53.845.

[0043] Preferably, the lens meets the following conditions: focal length meets EFL = 10.3 mm; total length of the lens meets TTL = 90.1 ± 0.3 mm; field of view of the lens meets DFOV = 180°

[0044] Preferably, the lens is suitable for doors with a thickness of 65-90 mm.

[0045] Embodiment 2:

[0046] An ultra-wide-angle cat's eye lens, which includes a first lens element 1, a second lens element 2, a third lens element 3, an aperture, a fourth lens element 4 and a fifth lens element 5 in order from the object side to the image side, and is characterized in that:

[0047] The first lens element is a meniscus lens with negative optical power convex to the object side;

[0048] The second lens element is a biconcave lens having negative optical power;

[0049] The third lens element is a meniscus lens with positive power convex to the image side;

[0050] The fourth lens element is a biconcave lens with negative optical power;

[0051] The fifth lens element is a plano-convex lens with positive refractive power and convex toward the image side;

[0052] Wherein, the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element are all glass spherical mirrors.

[0053] Preferably, the first lens element Nd1=1.745; Vd1=52.715.

[0054] Preferably, the second lens element Nd2=1.765; Vd2=49.625.

[0055] Preferably, the third lens element Nd3=1.815; Vd3=25.515.

[0056] Preferably, the fourth lens element Nd4=1.845; Vd4=23.825.

[0057] Preferably, the fifth lens element Nd5=1.725; Vd5=53.865.

[0058] Preferably, the lens meets the following conditions: focal length meets EFL = 10.3 mm; total length of the lens meets TTL = 90.1 ± 0.3 mm; field of view of the lens meets DFOV = 180°

[0059] Preferably, the lens is suitable for doors with a thickness of 65-90 mm.

[0060] Figure 3-Figure 7 Provides an effective optical performance graph for this embodiment;

[0061] like Figure 5 As shown in the (MTF resolution curve), it can be seen from the curve that the MTF curves of the meridian and sagittal of each field of view are relatively close, indicating that the imaging consistency of the wide-angle lens in the meridian (T) and sagittal (S) directions is relatively good, and the imaging contrast is better.

[0062] like Figure 7 As shown (relative brightness diagram), it can be seen from the curve that the wide-angle lens curve is relatively smooth, the image brightness of the captured pictures in the entire field of view is relatively close, and there will be no local dark situation.

[0063] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0064] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ultra-wide-angle cat-eye lens, which comprises a first lens element, a second lens element, a third lens element, an aperture, a fourth lens element and a fifth lens element in sequence from the object side to the image side, characterized in that: The first lens element is a meniscus lens having negative optical power convex to the object side; The second lens element is a biconcave lens having negative optical power; The third lens element is a meniscus lens having positive power convex to the image side; The fourth lens element is a biconcave lens having negative optical power; The fifth lens element is a plano-convex lens convex to the image side having positive power; Among them, the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element are all glass spherical lenses, and the components with optical refractive power in the cat's eye lens are only the above five lenses.

2. The ultra-wide-angle cat-eye lens according to claim 1, characterized in that , the first lens element satisfies: 1.70≤Nd1≤1.78; 52.62≤Vd1≤52.

72.

3. The ultra-wide-angle cat-eye lens according to claim 1, characterized in that , the second lens element satisfies: 1.73≤Nd2≤1.80; 49.56≤Vd2≤49.

65.

4. The ultra-wide-angle cat-eye lens according to claim 1, characterized in that , the third lens element satisfies: 1.76≤Nd3≤1.85; 25.43≤Vd3≤25.

52.

5. The ultra-wide-angle cat-eye lens according to claim 1, characterized in that , the fourth lens element satisfies: 1.80≤Nd4≤1.88; 23.75≤Vd4≤23.

83.

6. The ultra-wide-angle cat-eye lens according to claim 1, characterized in that , the fifth lens element satisfies: 1.68≤Nd5≤1.75:53.82≤Vd5≤53.

90.

7. The ultra-wide-angle cat-eye lens according to claim 1, characterized in that ,The lens meets the following conditions: the focal length satisfies EFL=10.3mm; the total length of the lens satisfies TTL=90.1±0.3mm; the field of view angle of the lens satisfies DFOV=180°.

8. The ultra-wide-angle cat-eye lens according to claim 1, characterized in that ,This lens is suitable for door thickness 65-90mm.

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