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CN-115793194-B - Optical lens for video displacement meter

CN115793194BCN 115793194 BCN115793194 BCN 115793194BCN-115793194-B

Abstract

The invention relates to the technical field of optical lenses, in particular to an optical lens for a video displacement meter, which comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along the incident direction of light rays, wherein a six-group seven-piece structure is adopted, so that the use requirement is met. The optical system has a central view field MTF value of more than 0.2 at 250lp/mm, an edge view field MTF value of more than 0.2 at 200lp/mm, fno of more than 50% relative illuminance, an optical total length of less than 15mm, a short object distance of 20mm, a horizontal object height of 35mm and optical distortion of 15%, and is suitable for a 1/2.7 chip used by a video displacement meter.

Inventors

  • WU LECHAO
  • LU BIN
  • YE XIAOLIANG
  • LI YUHANG

Assignees

  • 福建福特科光电股份有限公司

Dates

Publication Date
20260508
Application Date
20221123

Claims (5)

  1. 1. The optical lens for the video displacement meter is characterized by adopting a six-group seven-piece structure, and comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along the incidence direction of light rays; The first lens is a meniscus lens, the second lens is a biconcave lens, the third lens is a biconvex lens, the fourth lens and the fifth lens form a closely-connected gluing group, the sixth lens is a biconvex lens, and the seventh lens is a meniscus lens; The air interval range between the first lens and the second lens is 1 mm-2 mm, the air interval range between the second lens and the third lens is 0 mm-1 mm, the air interval range between the third lens and the diaphragm is 0 mm-1 mm, the air interval range between the diaphragm and the fourth lens is 0 mm-1 mm, the air interval range between the fifth lens and the sixth lens is 0 mm-1 mm, and the air interval range between the sixth lens and the seventh lens is 1 mm-2 mm.
  2. 2. The optical lens for a video displacement meter of claim 1, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens further satisfy the following optical conditions: 1.4<n1<1.5,70<v1<80; 1.5<n2<1.6,40<v2<50; 2.0<n3<2.1,20<v3<30; 1.7<n4<1.8,20<v4<30; 1.5<n5<1.6,60<v5<70; 1.5<n6<1.6,60<v6<70; 1.6<n7<1.7,30<v7<40; Wherein n1-n7 are refractive indexes of the first lens and the seventh lens in sequence, and v1-v7 are abbe coefficients of the first lens and the seventh lens in sequence.
  3. 3. The optical lens for a video displacement meter of claim 2, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens further satisfy the following optical conditions: the radius of curvature of the side surface of the first lens, which is far away from the second lens, ranges from 4 mm to 6mm, and the radius of curvature of the side surface of the first lens, which is close to the second lens, ranges from 2 mm to 3mm; The radius of curvature of the side surface, far away from the third lens, of the second lens ranges from-30 mm to-20 mm, and the radius of curvature of the side surface, close to the third lens, of the second lens ranges from 3 mm to 10mm; The radius of curvature of the side surface, far away from the fourth lens, of the third lens ranges from 0mm to 10mm, and the radius of curvature of the side surface, close to the fourth lens, of the third lens ranges from-10 mm to-5 mm; The radius of curvature of the side surface of the fourth lens, which is far away from the fifth lens, ranges from-5 mm to-4 mm, and the radius of curvature of the side surface of the fourth lens, which is close to the fifth lens, ranges from 2 mm to 3mm; the radius of curvature of the side surface, far away from the sixth lens, of the fifth lens ranges from 2 mm to 3mm, and the radius of curvature of the side surface, close to the sixth lens, of the fifth lens ranges from-5 mm to-3 mm; the radius of curvature of the side surface, far away from the seventh lens, of the sixth lens ranges from 5mm to 10mm, and the radius of curvature of the side surface, close to the seventh lens, of the sixth lens ranges from-10 mm to-5 mm; The radius of curvature of the side surface of the seventh lens, which is close to the sixth lens, ranges from-7 mm to-3 mm, and the radius of curvature of the side surface of the seventh lens, which is far away from the sixth lens, ranges from-7.1 mm.
  4. 4. The optical lens for a video displacement meter of claim 2, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens further satisfy the following optical conditions: the center thickness of the first lens ranges from 0mm to 1mm; the center thickness of the second lens ranges from 0mm to 1mm; the center thickness range of the third lens is 1 mm-2 mm; the center thickness range of the fourth lens is 1 mm-2 mm; the center thickness range of the fifth lens is 2 mm-3 mm; The center thickness range of the sixth lens is 1 mm-2 mm; the center thickness of the seventh lens ranges from 0mm to 1mm.
  5. 5. The optical lens for the video displacement meter according to claim 1, wherein the combined focal length of the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens is 4mm, and the optical total length of the optical lens is less than 15mm.

Description

Optical lens for video displacement meter Technical Field The invention relates to the technical field of optical lenses, in particular to an optical lens for a video displacement meter. Background With the gradual implementation of the digital and intelligent demands of pumping products, fire engines and the like, hydraulic cylinder displacement detection is one of the very important digital acquisition and fault monitoring points. In particular, in the aspect of object displacement mark detection in the industrial field, an imported pull-wire sensor is mainly used at present, however, the problems of high price, high failure rate and the like exist, the pull-wire sensor becomes the bottleneck of digital closed-loop control of pumping products, and the industry is in urgent need of digital video displacement meters with stable performance. Disclosure of Invention The invention aims to solve the technical problem of providing an optical lens for a video displacement meter. In order to solve the technical problems, the invention adopts the following technical scheme: an optical lens for a video displacement meter comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along the incidence direction of light rays; The first lens is a meniscus lens, the second lens is a biconcave lens, the third lens is a biconvex lens, the fourth lens and the fifth lens form a closely-connected gluing group, the sixth lens is a biconvex lens, and the seventh lens is a meniscus lens; The air interval range between the first lens and the second lens is 1 mm-2 mm, the air interval range between the second lens and the third lens is 0 mm-1 mm, the air interval range between the third lens and the diaphragm is 0 mm-1 mm, the air interval range between the diaphragm and the fourth lens is 0 mm-1 mm, the air interval range between the fifth lens and the sixth lens is 0 mm-1 mm, and the air interval range between the sixth lens and the seventh lens is 1 mm-2 mm. The invention has the beneficial effects that: The invention provides an optical lens for a video displacement meter, which comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along the incident direction of light rays, namely, a six-group seven-piece structure is adopted, so that the use requirement is met. The optical system has a central view field MTF value of more than 0.2 at 250lp/mm, an edge view field MTF value of more than 0.2 at 200lp/mm, fno of more than 50% relative illuminance, an optical total length of less than 15mm, a short object distance of 20mm, a horizontal object height of 35mm and optical distortion of 15%, and is suitable for a 1/2.7 chip used by a video displacement meter. Drawings FIG. 1 is a schematic view of an optical lens for a video displacement meter according to the present invention; FIG. 2 is a MTF diagram of an optical lens for a video displacement meter according to the present invention; FIG. 3 is a distortion chart of an optical lens for a video displacement meter according to the present invention; Description of the reference numerals: 1. First lens, 2, second lens, 3, third lens, 4, fourth lens, 5, fifth lens, 6, sixth lens, 7, seventh lens. Detailed Description In order to describe the technical contents, the achieved objects and effects of the present invention in detail, the following description will be made with reference to the embodiments in conjunction with the accompanying drawings. Referring to fig. 1, an optical lens for a video displacement meter according to the present invention includes a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens, which are sequentially disposed along a light incident direction; The first lens is a meniscus lens, the second lens is a biconcave lens, the third lens is a biconvex lens, the fourth lens and the fifth lens form a closely-connected gluing group, the sixth lens is a biconvex lens, and the seventh lens is a meniscus lens; The air interval range between the first lens and the second lens is 1 mm-2 mm, the air interval range between the second lens and the third lens is 0 mm-1 mm, the air interval range between the third lens and the diaphragm is 0 mm-1 mm, the air interval range between the diaphragm and the fourth lens is 0 mm-1 mm, the air interval range between the fifth lens and the sixth lens is 0 mm-1 mm, and the air interval range between the sixth lens and the seventh lens is 1 mm-2 mm. From the above description, the beneficial effects of the invention are as follows: The invention provides an optical lens for a video displacement meter, which comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along the