阅读说明：本技术 一种小型日夜两用车载光学系统及其工作方法 (small day and night dual-purpose vehicle-mounted optical system and working method thereof ) 是由 冯科 罗杰 黄杰 杨明亮 于 2019-08-31 设计创作，主要内容包括：本发明涉及一种小型日夜两用车载光学系统及其工作方法,包括从沿光线从左往右入射方向依次设置的前组镜片、光阑和后组镜片、滤光片,前组镜片包括平凹负透镜、平凸正透镜；后组镜片包括弯月正透镜,由双凸正透镜和弯月负透镜密接构成的胶合组；本发明还涉及一种小型日夜两用车载光学系统的工作方法。本发明具有大通光量、高清像质、结构小型紧凑等优点,本发明在-40℃~+85℃的温度范围内均能保持画面成像清晰,并且具有日夜两用的功能,可同时在可见光和近红外清晰成像,可用于车内人脸监测、人脸识别及手势识别。(The invention relates to a small day and night dual-purpose vehicle-mounted optical system and a working method thereof, wherein the small day and night dual-purpose vehicle-mounted optical system comprises a front group lens, a diaphragm, a rear group lens and an optical filter which are sequentially arranged along the direction of light incidence from left to right, the front group lens comprises a plano-concave negative lens and a plano-convex positive lens, the rear group lens comprises a meniscus positive lens and a cementing group formed by a double-convex positive lens and a meniscus negative lens in a sealing manner, and the working method of the small day and night dual-purpose vehicle-mounted optical system also relates to the working method of the small day and night dual-purpose vehicle-mounted optical system.)

1. A small-size day night dual-purpose on-vehicle optical system which characterized in that: the optical filter comprises a front group of lenses A, a diaphragm C, a rear group of lenses B and an optical filter D, wherein the front group of lenses A, the diaphragm C, the rear group of lenses B and the optical filter D are sequentially arranged along the incident direction of light rays from left to right, and the front group of lenses A comprises a plano-concave negative lens A1 and a plano-convex positive lens A2 which are sequentially arranged from left to right; the rear group of lenses B comprises a positive meniscus lens B1 and a gluing group formed by closely connecting a double convex positive lens B2 and a negative meniscus lens B3, wherein the convex surface of the positive plano-convex lens A2 faces to the diaphragm C, and the concave surface of the positive meniscus lens B1 faces to the diaphragm C.

2. The compact day and night vehicle mounted optical system of claim 1, further comprising: the air space between the front group of lenses A and the rear group of lenses B is 1.1 mm.

3. The compact day and night vehicle mounted optical system of claim 1, further comprising: the air space between the plano-concave negative lens A1 and the plano-convex positive lens A2 is 0.7 mm; the air space between the bonding group formed by bonding the meniscus positive lens B1 and the biconvex positive lens B2 and the meniscus negative lens B3 was 0.1 mm.

4. The compact day and night vehicle mounted optical system of claim 1, further comprising: the plano-concave negative lens A1 satisfies the relation: nd is less than or equal to 1.6, and Vd is more than or equal to 50; the plano-convex positive lens A2 satisfies the relation: nd is more than or equal to 1.8, and Vd is more than or equal to 40; the biconvex positive lens B2 satisfies the relation: nd is more than or equal to 1.5, and Vd is more than or equal to 60; the meniscus negative lens B3 satisfies the relation: nd is more than or equal to 1.8, Vd is more than or equal to 25, wherein Nd is refractive index, and Vd is Abbe constant.

5. The compact day and night vehicle mounted optical system of claim 1, further comprising:

The focal length F1 of the plano-concave negative lens A1 satisfies the following relation: F1/F is more than or equal to-1.2 and less than or equal to-0.8;

The focal length F2 of the plano-convex positive lens A2 satisfies the following relation: F2/F is more than or equal to 0.8 and less than or equal to 1.2;

the focal length F3 of the positive meniscus lens B1 satisfies the following relation: F3/F is more than or equal to-1.0 and less than or equal to-1.4;

The focal length F4 of the biconvex positive lens B2 satisfies the following relation: F4/F is more than or equal to 0.5 and less than or equal to 1;

The focal length F5 of the meniscus negative lens B3 satisfies the following relation: F5/F is not less than-1.5 and not more than-1;

The focal length values F4 and F5 of the double convex positive lens B2 and the meniscus negative lens B3 satisfy the following relations: F5/F4 is more than or equal to-1.8 and less than or equal to-1.2, wherein F is the total focal length value of the lens.

6. A method for operating a small day-night vehicle-mounted optical system, comprising using the small day-night vehicle-mounted optical system as claimed in any one of claims 1 to 5, characterized in that: the optical lens adopts a reverse distance structure, when the lens starts to work, the front group A with negative focal power can converge the incident angle of light rays with large visual angle, wherein the plano-concave negative lens A1 in the front group A is made of low-refractive-index materials, the plano-convex positive lens A2 in the front group A is made of high-refractive-index materials, and the plano-concave negative lens A1 and the convex positive lens A2 are matched to effectively reduce the image field curvature of the system; the biconvex positive lens B2 in the rear group B is made of a material with two characteristics of ultra-low dispersion and negative refractive index temperature coefficient, the ultra-low dispersion performance is favorable for reducing the near-infrared chromatic aberration of an optical system, good day and night dual-purpose performance is realized, and the negative refractive index temperature coefficient performance can effectively compensate the high and low temperature focal plane drift of the system.

Technical Field

The invention relates to a small day and night dual-purpose vehicle-mounted optical system and a working method thereof.

Background

with the development of the intelligent automobile industry, in-automobile scene monitoring is more and more important, the contents of the in-automobile scene monitoring include face monitoring, face recognition, gesture recognition and the like, and the corresponding requirements on the vehicle-mounted lens are higher and higher. The light environment difference in the vehicle at morning and night is large, the imaging quality difference at different time intervals can be caused by using the common vehicle-mounted lens, and the requirement of stable imaging of scene monitoring can not be met. The design difficulty of the day and night dual-purpose lens scheme is higher, and the small-sized lens scheme for monitoring in the vehicle on the market at present generally adopts an aspheric plastic lens, wherein the day and night confocal performance is not available for many of the small-sized lens schemes; and the plastic lens has a large expansion coefficient, and is easy to deform at high temperature, which can cause high-temperature image blurring. The invention provides a design scheme of an all-glass lens, and the reasonable glass material is selected, so that good day and night dual-purpose performance and athermal design are realized.

Disclosure of Invention

The invention improves the problems, namely the technical problem to be solved by the invention is that the common vehicle-mounted lens causes the imaging quality difference at different time intervals and cannot meet the requirement of stable imaging of scene monitoring.

The specific embodiment of the invention is as follows: a small day and night dual-purpose vehicle-mounted optical system comprises a front group of lenses A, a diaphragm C, a rear group of lenses B and an optical filter D, wherein the front group of lenses A, the diaphragm C, the rear group of lenses B and the optical filter D are sequentially arranged along the incident direction of light rays from left to right, and the front group of lenses A comprises a plano-concave negative lens A1 and a plano-convex positive lens A2 which are sequentially arranged from left to right; the rear group of lenses B comprises a positive meniscus lens B1 and a gluing group formed by closely connecting a double convex positive lens B2 and a negative meniscus lens B3, wherein the convex surface of the positive plano-convex lens A2 faces to the diaphragm C, and the concave surface of the positive meniscus lens B1 faces to the diaphragm C.

further, the air space between the front group of lenses A and the rear group of lenses B is 1.1 mm.

Further, the air space between the plano-concave negative lens a1 and the plano-convex positive lens a2 is 0.7 mm; the air space between the bonding group formed by bonding the meniscus positive lens B1 and the biconvex positive lens B2 and the meniscus negative lens B3 was 0.1 mm.

further, the plano-concave negative lens a1 satisfies the relationship: nd is less than or equal to 1.6, and Vd is more than or equal to 50; the plano-convex positive lens A2 satisfies the relation: nd is more than or equal to 1.8, and Vd is more than or equal to 40; the biconvex positive lens B2 satisfies the relation: nd is more than or equal to 1.5, and Vd is more than or equal to 60; the meniscus negative lens B3 satisfies the relation: nd is more than or equal to 1.8, Vd is more than or equal to 25, wherein Nd is refractive index, and Vd is Abbe constant.

The compact day and night vehicle mounted optical system of claim 1:

The focal length F1 of the plano-concave negative lens A1 satisfies the following relation: F1/F is more than or equal to-1.2 and less than or equal to-0.8;

The focal length F2 of the plano-convex positive lens A2 satisfies the following relation: F2/F is more than or equal to 0.8 and less than or equal to 1.2;

The focal length F3 of the positive meniscus lens B1 satisfies the following relation: F3/F is more than or equal to-1.0 and less than or equal to-1.4;

The focal length F4 of the biconvex positive lens B2 satisfies the following relation: F4/F is more than or equal to 0.5 and less than or equal to 1;

The focal length F5 of the meniscus negative lens B3 satisfies the following relation: F5/F is not less than-1.5 and not more than-1;

the focal length values F4 and F5 of the double convex positive lens B2 and the meniscus negative lens B3 satisfy the following relations: F5/F4 is more than or equal to-1.8 and less than or equal to-1.2, wherein F is the total focal length value of the lens.

The invention also comprises a working method of the small day and night dual-purpose vehicle-mounted optical system, which comprises the following steps of: the optical lens adopts a reverse distance structure, when the lens starts to work, the front group A with negative focal power can converge the incident angle of light rays with large visual angle, wherein the plano-concave negative lens A1 in the front group A is made of low-refractive-index materials, the plano-convex positive lens A2 in the front group A is made of high-refractive-index materials, and the plano-concave negative lens A1 and the convex positive lens A2 are matched to effectively reduce the image field curvature of the system; the biconvex positive lens B2 in the rear group B is made of a material with two characteristics of ultra-low dispersion and negative refractive index temperature coefficient, the ultra-low dispersion performance is favorable for reducing the near-infrared chromatic aberration of an optical system, good day and night dual-purpose performance is realized, and the negative refractive index temperature coefficient performance can effectively compensate the high and low temperature focal plane drift of the system.

Compared with the prior art, the invention has the following beneficial effects: the total length of the light path is short, the size is small, the installation space is greatly reduced, and the camera can be miniaturized;

The light-transmitting caliber is large, the light-entering quantity is sufficient at night, and the light-transmitting device is completely suitable for the environment with insufficient light in the vehicle;

The design of the all-glass lens is adopted, and compared with an aspheric plastic lens, the high-temperature and low-temperature environment image is clearer and more stable in performance;

the ultra-low dispersion glass is adopted, the near-infrared band chromatic aberration is greatly reduced, the good day and night dual-purpose performance is realized, the blue and violet edges of the lens are effectively corrected, the lens process is good, and the cost is low.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of an optical configuration of an embodiment of the present invention;

FIG. 2 is a graph of the visible light MTF for an embodiment of the present invention;

FIG. 3 is a graph of a near infrared MTF of an embodiment of the present invention;

FIG. 4 is a low temperature-40 ℃ MTF defocus curve for an embodiment of the present invention;

FIG. 5 is a high temperature +85 ℃ MTF defocus curve for an embodiment of the present invention.

in the figure: a 1-plano-concave negative lens; a 2-plano-convex positive lens; c-diaphragm; b1-meniscus positive lens; b2-biconvex positive lens; b3-meniscus negative lens; a D-filter; IMG-imaging plane.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1-2 and fig. 1, a small day and night dual-purpose vehicle-mounted optical system includes a front group of lenses a, a diaphragm C, a rear group of lenses B and an optical filter D, which are sequentially arranged along a light incident direction from left to right, wherein the front group of lenses a includes a plano-concave negative lens a1 and a plano-convex positive lens a2 which are sequentially arranged from left to right; the rear group of lenses B comprises a positive meniscus lens B1 and a gluing group, wherein the positive meniscus lens B1 and the gluing group are sequentially arranged from left to right, the gluing group is formed by closely connecting a double convex positive lens B2 and a negative meniscus lens B3, the drawing surface of the positive plano-convex lens A2 faces to the diaphragm C, and the concave surface of the positive meniscus lens B1 faces to the diaphragm C.

In this embodiment, the air space between the front lens group a and the rear lens group B is 1.11 mm.

in this embodiment, the air space between the plano-concave negative lens a1 and the plano-convex positive lens a2 is 0.67 mm; the air space between the bonding group formed by bonding the meniscus positive lens B1 and the biconvex positive lens B2 and the meniscus negative lens B3 was 0.1 mm.

In this embodiment, the distance from the plano-convex positive lens a2 to the diaphragm C is 0.05mm, and the distance from the diaphragm C to the meniscus positive lens B1 is 0.96 mm.

In this embodiment, a parallel flat plate is disposed between the negative meniscus lens B3 and the IMA image plane.

in this embodiment, the plano-concave negative lens a1 satisfies the following relation: nd is less than or equal to 1.6, and Vd is more than or equal to 50; the plano-convex positive lens A2 satisfies the relation: nd is more than or equal to 1.8, and Vd is more than or equal to 40; the biconvex positive lens B2 satisfies the relation: nd is more than or equal to 1.5, and Vd is more than or equal to 60; the meniscus negative lens B3 satisfies the relation: nd is more than or equal to 1.8, Vd is more than or equal to 25, wherein Nd is refractive index, and Vd is Abbe constant.

In this embodiment, the focal length F1 of the plano-concave negative lens a1 satisfies the following relationship: F1/F is more than or equal to-1.2 and less than or equal to-0.8; the focal length F2 of the plano-convex positive lens A2 satisfies the following relation: F2/F is more than or equal to 0.8 and less than or equal to 1.2; the focal length F3 of the positive meniscus lens B1 satisfies the following relation: F3/F is more than or equal to-1.0 and less than or equal to-1.4; the focal length F4 of the biconvex positive lens B2 satisfies the following relation: F4/F is more than or equal to 0.5 and less than or equal to 1; the focal length F5 of the meniscus negative lens B3 satisfies the following relation: F5/F is not less than-1.5 and not more than-1; the focal length values F4 and F5 of the double convex positive lens B2 and the meniscus negative lens B3 satisfy the following relations: F5/F4 is more than or equal to-1.8 and less than or equal to-1.2, wherein F is the total focal length value of the lens.

TABLE 1 specific lens parameters are as follows

in this embodiment, the technical indexes of the optical system are as follows:

(1) Focal length: EFFL =3.7 mm; (2) aperture F = 1.8; (3) the field angle: 2w is more than or equal to 74 degrees; (4) distortion of TV: less than-8 percent; (5) the diameter of the imaging circle is larger than phi 4.8; (6) the working wave band is as follows: 420-650 &940 +/-10 nm; (7) the total optical length TTL is less than or equal to 12.5mm, and the optical back intercept BFL is more than or equal to 4 mm; (8) the lens is suitable for a CCD or CMOS camera with 200 ten thousand pixels.

the embodiment also relates to a working method of the small-sized vehicle-mounted optical system for day and night use, which comprises the following steps:

The optical lens adopts a reverse distance structure, when the lens starts to work, the front group A with negative focal power can converge the incident angle of light rays with large visual angle, wherein the plano-concave negative lens A1 in the front group A is made of ZK series glass with low refractive index material, the plano-convex positive lens A2 in the front group A is made of ZLAF series glass with high refractive index material, and the plano-concave negative lens A1 and the convex positive lens A2 are matched to effectively reduce the image field curvature of the system; the double-convex positive lens B2 in the rear group B is made of ED glass with two characteristics of ultra-low dispersion and negative refractive index temperature coefficient, the ultra-low dispersion performance is beneficial to reducing the near-infrared chromatic aberration of an optical system, good day and night dual-purpose performance is realized, and the negative refractive index temperature coefficient performance can effectively compensate the high and low temperature focal plane drift of the system.

as can be seen from fig. 2 and 3, the MTF of the optical system in the visible light and near infrared bands is well represented, and the optical system has good day and night dual-purpose performance and can meet the resolution requirement of two million high-definition.

FIGS. 4 and 5 are MTF defocusing curves of the optical system at a low temperature of-40 ℃ and a high temperature of +85 ℃, wherein the defocusing amount of the low temperature is 4 μm, the defocusing amount of the high temperature is 2 μm, the MTF attenuation is small, and the high and low temperature image definition is completely met.

Any embodiment disclosed herein above is meant to disclose, unless otherwise indicated, all numerical ranges disclosed as being preferred, and any person skilled in the art would understand that: the preferred ranges are merely those values which are obvious or representative of the technical effect which can be achieved. Since the numerical values are too numerous to be exhaustive, some of the numerical values are disclosed in the present invention to illustrate the technical solutions of the present invention, and the above-mentioned numerical values should not be construed as limiting the scope of the present invention.

if the terms "first," "second," etc. are used herein to define parts, those skilled in the art will recognize that: the terms "first" and "second" are used merely to distinguish one element from another in a descriptive sense and are not intended to have a special meaning unless otherwise stated.

Meanwhile, if the invention as described above discloses or relates to parts or structural members fixedly connected to each other, the fixedly connected parts can be understood as follows, unless otherwise stated: a detachable fixed connection (for example using bolts or screws) is also understood as: non-detachable fixed connections (e.g. riveting, welding), but of course, fixed connections to each other may also be replaced by one-piece structures (e.g. manufactured integrally using a casting process) (unless it is obviously impossible to use an integral forming process).

in addition, terms used in any technical solutions disclosed in the present invention to indicate positional relationships or shapes include approximate, similar or approximate states or shapes unless otherwise stated.

Any part provided by the invention can be assembled by a plurality of independent components or can be manufactured by an integral forming process.

Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and not to limit the same; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.