CN111338050A

CN111338050A - Lens optical axis deviation method convenient for secondary adjustment

Info

Publication number: CN111338050A
Application number: CN201811546087.7A
Authority: CN
Inventors: 张微微
Original assignee: Beijing Changfeng Kewei Photoelectric Technology Co ltd
Current assignee: Beijing Changfeng Kewei Photoelectric Technology Co ltd
Priority date: 2018-12-18
Filing date: 2018-12-18
Publication date: 2020-06-26

Abstract

The invention provides a lens optical axis offset method convenient for secondary adjustment, which adopts a front lens group, a relay image-transferring front group, a first reflector, a second reflector, a relay image-transferring rear group, a detector protection window, a detector induction surface and an inclined pad to form an optical axis offset system; the first reflector and the relay image transfer front group form an included angle of 45 degrees, and the second reflector is vertical to the first reflector; the long side direction of the detector sensing surface is defined as the x axis of a coordinate system, and a connecting line of the center of the front lens group and the center of the detector sensing surface forms a certain included angle with the x axis; the inclined cushion block is of a triangular prism structure, edges of the inclined cushion block are arranged along the length direction of the lens cone, and the edges positioned above the inclined cushion block are parallel to a connecting line of the center of the front lens group and the center of the sensing surface of the detector; the deviation of the optical axis can be realized by adjusting the inclination angle of the inclined pad block close to one side of the lens cone.

Description

Lens optical axis deviation method convenient for secondary adjustment

Technical Field

The invention belongs to the technical field of refrigeration type infrared thermal imaging, and particularly relates to a space optical axis deviation method which is small in size, low in cost and convenient for secondary adjustment.

Background

In the design process of the refrigeration type infrared thermal imaging lens, in order to ensure 100% of cold diaphragm effect, a relay image transfer system is used to realize matching of the optical system diaphragm and the diaphragm built in the refrigeration type infrared detector. Because of the introduction of relay imaging systems and the large size of refrigerated infrared detectors, designers often use an optical axis offset approach in order to reduce the space occupied by the optical system or to accommodate different outer envelopes.

The traditional optical axis deviation method is shown in fig. 1, and comprises a front lens group 1, a relay image-transferring front group 2, a first reflecting mirror 3, a second reflecting mirror 4, a third reflecting mirror 5, a fourth reflecting mirror 6, a relay image-transferring rear group 7, a detector protection window 8 and a detector sensing surface 9; the long side direction of the detector sensing surface 9 is defined as the x axis of a coordinate system, the short side direction is defined as the y axis of the coordinate system, the direction vertical to the sensing surface is defined as the z axis, and the center of a focal plane is defined as the origin o of the coordinate system; the reflecting mirror is parallel to the x axis and forms an included angle of 45 degrees with the xoz surface, the reflecting mirror IV is perpendicular to the reflecting mirror I, the reflecting mirror II is parallel to the z axis and forms an included angle of 45 degrees with the yoz surface, and the reflecting mirror III is perpendicular to the reflecting mirror II; the center of each mirror intersects the optical axis.

The principle of optical axis deviation is shown in fig. 2, and the second reflecting mirror and the third reflecting mirror realize the deviation distance X in the X-axis direction; the first reflecting mirror, the second reflecting mirror, the third reflecting mirror and the fourth reflecting mirror together realize the offset distance (Y2-Y1) in the Y-axis direction, and the offset of the optical axis at any position is realized through the synthesis of the two directions. The offset method occupies a large space, is complex in optical adjustment and is not beneficial to secondary adjustment of the optical axis.

Disclosure of Invention

The invention aims to simplify the existing optical axis offset mode, reduce the space occupied by an offset structure, reduce the difficulty of secondary movement of an optical axis and provide a space optical axis offset method which has small volume, low cost and convenient secondary adjustment.

The technical scheme of the invention is as follows:

a lens optical axis deviation method convenient for secondary adjustment is characterized in that: an optical axis deviation system is formed by adopting a front lens group, a relay image transfer front group, a first reflecting mirror, a second reflecting mirror, a relay image transfer rear group, a detector protection window, a detector sensing surface and an inclined pad; the front lens group, the relay image-transferring front group, the first reflector, the second reflector, the relay image-transferring rear group, the detector protection window and the detector induction surface are arranged in the lens cone, and the inclined cushion block is arranged on the outer side of the lens cone; the front lens group and the relay image-transferring front group are parallel to each other and have optical axes coincident; the relay image-rotating rear group, the detector protection window and the detector sensing surface are parallel to each other, and the optical axes of the relay image-rotating rear group and the detector protection window are coincident; optical axes of the front lens group and the relay image-transferring front group are defined as an axis A, and optical axes of the relay image-transferring rear group, the detector protection window and the detector sensing surface are defined as an axis B; a certain distance is arranged between the optical axis A and the optical axis B; arranging a first reflector vertical to a plane formed by an optical axis A and an optical axis B, and forming an included angle of 45 degrees with a relay image transfer front group, wherein the optical axis A passes through the center of the first reflector; arranging the second reflector to be vertical to the first reflector, wherein the optical axis B passes through the center of the second reflector; the long side direction of the detector sensing surface is defined as the x axis of a coordinate system, the short side direction is defined as the y axis of the coordinate system, the direction vertical to the detector sensing surface is defined as the z axis, and the center of a focal plane is defined as the origin o of the coordinate system; a connecting line AB between the center of the front lens group and the center of the sensing surface of the detector forms a certain included angle theta with the x axis; the inclined cushion block is of a triangular prism structure, edges of the inclined cushion block are arranged on one side of the lens cone along the length direction of the lens cone, one side surface of the inclined cushion block is in contact with the lens cone, and the edges positioned above the inclined cushion block are parallel to a connecting line AB between the center of the front lens group and the center of the sensing surface of the detector; the size of the included angle theta can be adjusted by adjusting the inclination angle of one side, close to the lens cone, of the inclined cushion block, so that the deviation of the optical axis is realized.

Compared with the prior art, the invention has the advantages that:

firstly, the invention only uses two reflectors, and compared with the traditional offset mode, the invention reduces two reflectors and reduces the product cost.

Secondly, the positions of four reflectors need to be adjusted in the traditional method, and the adjustment process is complex; the invention only needs to adjust the positions of the two reflectors relative to the light path, thereby simplifying the adjustment process.

In the traditional optical axis deviation method, the relative position of the reflector changes to a certain extent every time the reflector is adjusted, the change of the position of the reflector can cause the change of image quality, the relative position of the reflector needs to be adjusted again, the process is relatively complex, secondary operation is not easy, and secondary adjustment is convenient; the invention adjusts the base angle theta of the inclined cushion block₁The optical axis offset adjustment can be performed conveniently without introducing image quality variation.

Fourthly, four reflectors are adopted in the traditional optical axis deviation mode, the waste of overlapping space of the distance Y1 is caused in the Y-axis direction, two more reflectors are used, and a fixing and adjusting structure of the two reflectors is also increased; the invention can realize the secondary adjustment of the optical axis only by adopting two reflectors and a cushion block without tolerance requirement, and has less parts and small volume.

Drawings

FIG. 1 is a schematic diagram of a conventional optical axis shifting system;

FIG. 2 is a schematic diagram of a prior art optical axis shifting system;

FIG. 3 is a schematic diagram of the optical axis shifting system of the present invention;

fig. 4 is a schematic diagram of the optical axis shifting system of the present invention.

Detailed Description

As shown in fig. 3 and 4, the optical axis deviation system is composed of a front lens group 1, a relay image-transferring front group 2, a first reflector 10, a second reflector 11, a relay image-transferring rear group 7, a detector protection window 8, a detector sensing surface 9 and an inclined cushion block 12; the front lens group 1, the relay image-transferring front group 2, the first reflector 10, the second reflector 11, the relay image-transferring rear group 7, the detector protection window 8 and the detector induction surface 9 are arranged in the lens cone, and the inclined cushion block 12 is arranged on the outer side of the lens cone;

the front lens group 1 and the relay image-transferring front group 2 are parallel to each other and have optical axes coincident; the relay image-rotating rear group 7, the detector protection window 8 and the detector induction surface 9 are mutually parallel and the optical axes are superposed;

optical axes of the front lens group 1 and the relay image-transferring front group 2 are defined as an axis A, and optical axes of the relay image-transferring rear group 7, the detector protection window 8 and the detector sensing surface 9 are defined as an axis B;

a certain distance is arranged between the optical axis A and the optical axis B;

the first reflector 10 is arranged to be vertical to a plane formed by the optical axis A and the optical axis B, and forms an included angle of 45 degrees with the relay image transfer front group 2, and the optical axis A passes through the center of the first reflector 10;

the second reflector 11 is arranged perpendicular to the first reflector 10, and the optical axis B passes through the center of the second reflector 11;

the long side direction of the detector sensing surface 9 is defined as the x axis of a coordinate system, the short side direction is defined as the y axis of the coordinate system, the direction vertical to the detector sensing surface is defined as the z axis, and the center of a focal plane is defined as the origin o of the coordinate system;

a connecting line AB of the center 1 of the front lens group and the center 9 of the sensing surface of the detector forms a certain included angle theta with an x axis;

the inclined pad 12 is a triangular prism structure, the edge of which is arranged at one side of the lens barrel along the length direction of the lens barrel, one side surface of which is contacted with the lens barrel, and the edge (K side in figure 4) at the upper part of which is positioned at the front partA connecting line AB between the center of the lens group 1 and the center of the detector sensing surface 9 is parallel; by adjusting the inclination angle theta of the inclined cushion block 12 at the side close to the lens cone₁The size of an included angle theta between a connecting line AB of the center 1 of the front lens group and the center 9 of the sensing surface of the detector and the x axis can be adjusted, so that the deviation of the optical axis is realized.

The first reflector 10 is made of environment-friendly glass h-bak7, the hardness is 547, the first reflector is not easy to deform, the cold machining process is mature, and the precision of the reflecting surface is easy to guarantee. In the present system, it deflects the optical axis by 90 degrees for deflecting the optical path;

the second reflecting mirror 11 is made of environment-friendly glass h-bak7, the hardness is 547, the second reflecting mirror is not easy to deform, the optical cold machining process is mature, and the reflecting surface accuracy is easy to guarantee. Which deflects the optical axis by 90 degrees, counteracting the 90 degree optical axis deflection introduced by the mirror 10.

The inclined cushion block is made of aluminum materials and is easy to process. Presetting the inclination angle theta according to the preset optical axis deviation value during processing₁Size.

Claims

1. A lens optical axis deviation method convenient for secondary adjustment is characterized in that: an optical axis deviation system is formed by adopting a front lens group, a relay image transfer front group, a first reflecting mirror, a second reflecting mirror, a relay image transfer rear group, a detector protection window, a detector sensing surface and an inclined pad; the front lens group, the relay image-transferring front group, the first reflector, the second reflector, the relay image-transferring rear group, the detector protection window and the detector induction surface are arranged in the lens cone, and the inclined cushion block is arranged on the outer side of the lens cone; the front lens group and the relay image-transferring front group are parallel to each other and have optical axes coincident; the relay image-rotating rear group, the detector protection window and the detector sensing surface are parallel to each other, and the optical axes of the relay image-rotating rear group and the detector protection window are coincident; optical axes of the front lens group and the relay image-transferring front group are defined as an axis A, and optical axes of the relay image-transferring rear group, the detector protection window and the detector sensing surface are defined as an axis B; a certain distance is arranged between the optical axis A and the optical axis B; arranging a first reflector vertical to a plane formed by an optical axis A and an optical axis B, and forming an included angle of 45 degrees with a relay image transfer front group, wherein the optical axis A passes through the center of the first reflector; arranging the second reflector to be vertical to the first reflector, wherein the optical axis B passes through the center of the second reflector; the long side direction of the detector sensing surface is defined as the x axis of a coordinate system, the short side direction is defined as the y axis of the coordinate system, the direction vertical to the detector sensing surface is defined as the z axis, and the center of a focal plane is defined as the origin o of the coordinate system; a connecting line AB between the center of the front lens group and the center of the sensing surface of the detector forms a certain included angle theta with the x axis; the inclined cushion block is of a triangular prism structure, edges of the inclined cushion block are arranged on one side of the lens cone along the length direction of the lens cone, one side surface of the inclined cushion block is in contact with the lens cone, and the edges positioned above the inclined cushion block are parallel to a connecting line AB between the center of the front lens group and the center of the sensing surface of the detector; the size of the included angle theta can be adjusted by adjusting the inclination angle of one side, close to the lens cone, of the inclined cushion block, so that the deviation of the optical axis is realized.