阅读说明：本技术 一种偏轴棱镜色散型高光谱成像仪的高精度快速装调方法 (High-precision quick assembling and adjusting method for off-axis prism dispersion type hyperspectral imager ) 是由 贾昕胤 李立波 沈重 杨莹 王飞橙 张兆会 李思远 于 2021-07-09 设计创作，主要内容包括：本发明提供一种偏轴棱镜色散型高光谱成像仪的高精度快速装调方法,解决现有偏轴棱镜色散型高光谱成像仪存在装调设备复杂、装调难度大以及装调时间长的问题。该方法包括以下步骤：步骤一、装调基准偏轴球面镜；步骤二、对其他偏轴球面镜进行装调；步骤三、获取各偏轴球面镜球面的球心坐标；步骤四、固定各偏轴球面镜；步骤五、完成系统的装调。本发明装调方法通过三坐标测量仪与点源显微镜互相配合,可实现各偏轴球面镜的六自由度调整,进而可快速高精度的实现偏轴棱镜色散型光谱仪的系统装调。(The invention provides a high-precision quick assembling and adjusting method of an off-axis prism dispersion type hyperspectral imager, which solves the problems of complex assembling and adjusting equipment, high assembling and adjusting difficulty and long assembling and adjusting time of the existing off-axis prism dispersion type hyperspectral imager. The method comprises the following steps: firstly, installing and adjusting a reference off-axis spherical mirror; step two, adjusting other off-axis spherical mirrors; step three, obtaining the spherical center coordinates of each off-axis spherical mirror; step four, fixing each off-axis spherical mirror; and step five, completing the installation and adjustment of the system. The adjusting method can realize the six-degree-of-freedom adjustment of each off-axis spherical mirror through the mutual matching of the three-coordinate measuring instrument and the point source microscope, and further can realize the system adjustment of the off-axis prism dispersion spectrometer with high speed and high precision.)

1. A high-precision quick assembling and adjusting method for an off-axis prism dispersion type hyperspectral imager comprises a substrate, and an encoding assembly, an optical unit and a detector which are arranged on the substrate, wherein the optical unit comprises a plurality of off-axis spherical mirrors; the method is characterized by comprising the following steps:

firstly, installing and adjusting a reference off-axis spherical mirror;

1.1) taking one of the off-axis spherical mirrors as a reference off-axis spherical mirror, mounting the reference off-axis spherical mirror on a substrate, measuring the angle between the back plane of the reference off-axis spherical mirror and the mounting surface of the substrate by adopting a three-coordinate measuring instrument, and adjusting the posture of the reference off-axis spherical mirror according to the measured value to ensure that the back plane of the reference off-axis spherical mirror is vertical to the plane of the substrate;

1.2) measuring the convex spherical center height Z1 of the reference off-axis spherical mirror by adopting a three-coordinate measuring instrument, and recording the convex spherical center height Z1;

step two, adjusting other off-axis spherical mirrors;

2.1) mounting the off-axis spherical mirror on a substrate, measuring the angle between the reference surface of the off-axis spherical mirror and the mounting surface of the substrate by adopting a three-coordinate measuring instrument, and adjusting the posture of the off-axis spherical mirror according to the measured value to ensure that the reference surface of the off-axis spherical mirror is vertical to the mounting plane of the substrate, thereby completing the pitch angle adjustment of the off-axis spherical mirror;

2.2) measuring the front surface sphere center height Z2 and the rear surface sphere center height Z3 of the off-axis spherical mirror by adopting a three-coordinate measuring instrument, and adjusting the posture of the off-axis spherical mirror again to ensure that Z2 is equal to Z3, thereby completing the adjustment of the rotation angle of the off-axis spherical mirror;

2.3) adjusting the posture of the off-axis spherical mirror again to ensure that Z2 is Z3 is Z1, and completing the height adjustment of the off-axis spherical mirror;

step three, obtaining the spherical center coordinates of each off-axis spherical mirror;

establishing a system coordinate system, wherein the system coordinate system takes the convex spherical center of the reference off-axis spherical mirror as the origin of coordinates, the central axis of the reference off-axis spherical mirror as the X axis, the Z axis as the vertical height direction and the Z axis perpendicular to the X axis, determining the Y axis by the right-hand rule, and determining the spherical center coordinates of the spherical surface of each off-axis spherical mirror according to the design values;

step four, fixing each off-axis spherical mirror;

4.1) placing a metal ball at the theoretical center of sphere position of the front surface of the off-axis spherical mirror, focusing the point source microscope on the center of sphere of the metal ball, and recording the barycentric coordinate D2 of an image point on the image surface of the point source microscope;

4.2) removing the metal sphere, adjusting the X-direction displacement, the Y-direction displacement and the azimuth angle of the off-axis spherical mirror, enabling the image point coordinates D3 of the light beam emitted by the point source microscope imaged by the off-axis spherical mirror to be consistent with D2, and fixing the off-axis spherical mirror;

fifthly, assembling and adjusting the off-axis prism dispersion type hyperspectral imager;

5.1) mounting the coding assembly on the substrate, and placing a detector at the image surface of the optical unit;

and 5.2) installing a star point plate on the coding assembly, observing a star point image through a point source microscope, finely adjusting the coding assembly to the optimal imaging quality, and completing the adjustment of the off-axis prism dispersion type hyperspectral imager.

2. The high-precision fast adjusting method of the off-axis prism dispersion type hyperspectral imager according to claim 1 is characterized in that: in the step 1.1), the back plane of the reference off-axis spherical mirror is perpendicular to the plane of the substrate by repairing and grinding a trimming pad between the reference off-axis spherical mirror and the substrate.

3. The high-precision fast adjusting method of the off-axis prism dispersion type hyperspectral imager according to claim 2 is characterized in that: and in the second step, the posture of the off-axis spherical mirror is adjusted by repairing and grinding a trimming pad between the off-axis spherical mirror and the substrate.

4. The high-precision fast adjusting method of the off-axis prism dispersion type hyperspectral imager according to claim 1, 2 or 3, characterized in that: and 4.2), removing the metal ball, and adjusting the X-direction displacement, the Y-direction displacement and the azimuth angle of the off-axis spherical mirror through the screw through hole amount.

5. The high-precision fast adjusting method of the off-axis prism dispersion type hyperspectral imager according to claim 4 is characterized in that: in step 2.1), the reference surface of the off-axis spherical mirror is a plane which is easy to measure and is processed by the off-axis spherical mirror during optical processing.

Technical Field

The invention belongs to the field of precise assembly and adjustment of hyperspectral imagers, and particularly relates to a high-precision rapid assembly and adjustment method of an off-axis prism dispersion type hyperspectral imager.

Background

The dispersive hyperspectral imager can adopt two modes of grating dispersion and prism dispersion. Compared with grating dispersion, prism dispersion has great advantages in energy utilization rate and low processing difficulty. However, since the dispersion of the glass material is usually nonlinear, the spectral sampling interval after the prism dispersion is also nonlinear, and the prism dispersion also introduces large spectral distortion and aberration, it is necessary to correct the aberration of the optical system by adjusting the eccentricity and tilt of the dispersion prism and the reflection prism, thereby improving the image quality of the system. However, the optical elements in the prism dispersion spectrometer are not always in a common optical axis and are off-axis. The assembly and adjustment precision of each off-axis optical element also directly influences the imaging quality of the hyperspectral imager.

The coaxial optical system can ensure the coaxiality of all optical elements through centering processing, but the complex off-axis prism dispersion optical system still lacks an efficient assembly and adjustment method and has the problems of high assembly and adjustment difficulty and long assembly and adjustment time. Chinese patent CN102141439A discloses an installation and adjustment method of a convex grating imaging spectrometer, which is based on an interferometer and a standard compensation mirror, and completes the assembly of a system by a spectrogram direct reading method.

Disclosure of Invention

The invention provides a high-precision quick assembling and adjusting method of an off-axis prism dispersion type hyperspectral imager, which solves the problems of complex assembling and adjusting equipment, high assembling and adjusting difficulty and long assembling and adjusting time of the existing off-axis prism dispersion type hyperspectral imager.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

a high-precision quick assembling and adjusting method for an off-axis prism dispersion type hyperspectral imager comprises a substrate, and an encoding assembly, an optical unit and a detector which are arranged on the substrate, wherein the optical unit comprises a plurality of off-axis spherical mirrors; the method comprises the following steps:

firstly, installing and adjusting a reference off-axis spherical mirror;

1.1) taking one of the off-axis spherical mirrors as a reference off-axis spherical mirror, mounting the reference off-axis spherical mirror on a substrate, measuring the angle between the back plane of the reference off-axis spherical mirror and the mounting surface of the substrate by adopting a three-coordinate measuring instrument, and adjusting the posture of the reference off-axis spherical mirror according to the measured value to ensure that the back plane of the reference off-axis spherical mirror is vertical to the plane of the substrate;

1.2) measuring the convex spherical center height Z1 of the reference off-axis spherical mirror by adopting a three-coordinate measuring instrument, and recording the convex spherical center height Z1;

step two, adjusting other off-axis spherical mirrors;

2.1) mounting the off-axis spherical mirror on a substrate, measuring the angle between the reference surface of the off-axis spherical mirror and the mounting surface of the substrate by adopting a three-coordinate measuring instrument, and adjusting the posture of the off-axis spherical mirror according to the measured value to ensure that the reference surface of the off-axis spherical mirror is vertical to the mounting plane of the substrate, thereby completing the pitch angle adjustment of the off-axis spherical mirror;

2.2) measuring the front surface sphere center height Z2 and the rear surface sphere center height Z3 of the off-axis spherical mirror by adopting a three-coordinate measuring instrument, and adjusting the posture of the off-axis spherical mirror again to ensure that Z2 is equal to Z3, thereby completing the adjustment of the rotation angle of the off-axis spherical mirror;

2.3) adjusting the posture of the off-axis spherical mirror again to ensure that Z2 is Z3 is Z1, and completing the height adjustment of the off-axis spherical mirror;

step three, obtaining the spherical center coordinates of each off-axis spherical mirror;

establishing a system coordinate system, wherein the system coordinate system takes the convex spherical center of the reference off-axis spherical mirror as the origin of coordinates, the central axis of the reference off-axis spherical mirror as the X axis, the Z axis as the vertical height direction and the Z axis perpendicular to the X axis, determining the Y axis by the right-hand rule, and determining the spherical center coordinates of the spherical surface of each off-axis spherical mirror according to the design values;

step four, fixing each off-axis spherical mirror;

4.1) placing a metal ball at the theoretical center of sphere position of the front surface of the off-axis spherical mirror, focusing the point source microscope on the center of sphere of the metal ball, and recording the barycentric coordinate D2 of an image point on the image surface of the point source microscope;

4.2) removing the metal sphere, adjusting the X-direction displacement, the Y-direction displacement and the azimuth angle of the off-axis spherical mirror, enabling the image point coordinates D3 of the light beam emitted by the point source microscope imaged by the off-axis spherical mirror to be consistent with D2, and fixing the off-axis spherical mirror;

fifthly, assembling and adjusting the off-axis prism dispersion type hyperspectral imager;

5.1) mounting the coding assembly on the substrate, and placing a detector at the image surface of the optical unit;

and 5.2) installing a star point plate on the coding assembly, observing a star point image through a point source microscope, finely adjusting the coding assembly to the optimal imaging quality, and completing the adjustment of the off-axis prism dispersion type hyperspectral imager.

Further, in step 1.1), the back plane of the reference off-axis spherical mirror is perpendicular to the substrate plane by lapping the trimming pad between the reference off-axis spherical mirror and the substrate.

Further, in the second step, the posture of the off-axis spherical mirror is adjusted by repairing and grinding a trimming pad between the off-axis spherical mirror and the substrate.

Further, in the step 4.2), the metal ball is removed, and the X-direction displacement, the Y-direction displacement and the azimuth angle of the off-axis spherical mirror are adjusted through the screw through hole amount.

Further, in step 2.1), the reference surface of the off-axis spherical mirror is a plane which is easy to measure and is processed by the off-axis spherical mirror during optical processing.

Compared with the prior art, the invention has the beneficial effects that:

1. the adjusting method can realize the six-degree-of-freedom adjustment of each off-axis spherical mirror through the mutual matching of the three-coordinate measuring instrument and the point source microscope, and further can realize the system adjustment of the off-axis prism dispersion spectrometer with high speed and high precision.

2. The assembly and debugging method of the invention converts the assembly and debugging of the optical unit into various simple geometric relations such as angle relation and adjustment of coordinates of a sphere center point, overcomes the equipment complexity of the traditional assembly and debugging method by utilizing an imaging spectrogram, reduces the technical requirements on assembly personnel, and greatly reduces the assembly and debugging difficulty.

3. The adjusting method can reduce the difficulty of structural design of the optical instrument, and has the advantages of low adjusting cost, short adjusting time, high adjusting precision and simple required adjusting equipment.

Drawings

FIG. 1 is a schematic diagram of an optical system of an off-axis prism dispersion type hyperspectral imager in an embodiment of the invention;

FIG. 2 is a schematic structural diagram of an off-axis prism dispersion type hyperspectral imager in an embodiment of the invention;

FIG. 3 is a schematic view of an optical reference plane of a curved prism in the method of the present invention;

FIG. 4 is a schematic diagram of a coordinate system established by using the theoretical spherical center position of each optical element spherical surface of the present invention and the convex spherical center of the secondary reflector as the origin.

Reference numerals: 1-coding component, 2-curved prism component, 3-curved reflecting prism component, 4-secondary reflecting mirror component, 5-curved prism component, 6-curved reflecting prism component, 7-folding axis mirror component, 8-detector, 9-substrate, 11-coding template, 21-curved prism component, 31-curved reflecting prism component, 41-secondary reflecting mirror, 51-curved prism component, 61-curved reflecting prism component, 71-folding axis mirror, 81-detector support, 22-curved prism component trimming pad, 32-curved reflecting prism component trimming pad, 42-secondary reflecting mirror component trimming pad, 211-front reference surface.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention and are not intended to limit the scope of the present invention.

The invention provides a high-precision quick assembly and adjustment method of an off-axis prism dispersion type hyperspectral imager, which realizes high-precision and low-cost assembly and adjustment of the off-axis prism dispersion type hyperspectral imager and can be applied to high-precision quick assembly and adjustment of various off-axis optical systems. The off-axis prism dispersion type hyperspectral imager comprises a substrate, and an encoding assembly, an optical unit and a detector which are arranged on the substrate, wherein the optical unit comprises a plurality of off-axis spherical mirrors.

The invention takes an offner hyperspectral imaging system based on a curved prism disclosed in Chinese patent CN112013954A as an example to explain the installation and adjustment of the existing off-axis prism dispersion type hyperspectral imager. As shown in fig. 1, the optical system of the off-axis prism dispersion spectrometer mainly comprises an encoding component 1, an optical unit and a detector 8, wherein the optical unit comprises a first curved surface prism 21, a first curved surface reflection prism 31, a secondary reflector 41, a second curved surface prism 51, a second curved surface reflection prism 61 and a folding axis mirror 71, and axial leaning surfaces are required to be designed when each of the first curved surface prism and the second curved surface reflection prism are processed.

As shown in fig. 2, the off-axis prism dispersion hyperspectral imager for implementing the optical system mainly comprises an encoding component 1, a first curved prism component 2, a first curved reflection prism component 3, a secondary reflection mirror component 4, a second curved prism component 5, a second curved reflection prism component 6, a folding axis mirror component 7 and a detector 8. Each component adopts the mounting mode of sharing the base plate 9, each prism is independently mounted on each structure frame firstly, and the structure frame of each prism is fixedly connected with the base plate 9 through a layer of trimming pad.

During optical processing, each curved prism and each curved reflection prism need to position a reference surface on the processing axis of the surface thereof, such as the front reference surface 211 of the curved prism one 21 in fig. 3. The local coordinate system for each lens group is located as follows: the front surface optical axis direction is the X direction, the height direction perpendicular to the substrate 9 is the Z direction, and the Y direction is determined by the right-hand rule. The pitching angle for positioning each lens group is a rotation angle around the Y axis, the azimuth angle for positioning each lens group is a rotation angle around the Z axis, and the rotation angle for positioning each lens group is a rotation angle around the X axis.

Taking the off-axis prism dispersive hyperspectral imager as an example, the invention provides a high-precision quick adjustment method of the off-axis prism dispersive hyperspectral imager, which comprises the following steps:

step one, installing and adjusting a secondary reflector component 4;

firstly, mounting a secondary reflector assembly 4 on a substrate 9, measuring the angle between a back plane C0 of the secondary reflector 41 and a mounting surface of the substrate 9 by using a three-coordinate measuring instrument, ensuring that a back plane C0 of the secondary reflector 41 is perpendicular to the plane of the substrate 9 by repairing and grinding a secondary reflector assembly trimming pad 42, measuring the height position Z1 of the spherical center of a convex surface C1 of the secondary reflector 41 by using the three-coordinate measuring instrument, recording, and finishing the assembly and adjustment of other lens groups by taking the secondary reflector 41 as a reference in the subsequent assembly and adjustment;

step two, installing and adjusting a curved surface prism assembly 2;

the first curved prism assembly 2 is installed on the base plate 9, a three-coordinate measuring instrument is adopted to measure the angle between the front reference surface 211 of the first curved prism 21 and the installation surface of the base plate 9, and the first sub-curved prism assembly trimming pad 22 is repaired and ground to ensure that the front reference surface 211 of the first curved prism 21 is perpendicular to the installation plane of the base plate 9, so that the adjustment of the pitching angle of the first curved prism assembly 2 is completed.

Measuring a sphere center height coordinate Z2 of the front surface C2 and a sphere center height Z3 of the rear surface C3 of the first curved prism assembly 2 by using a three-coordinate measuring instrument, and ensuring that Z2 is Z3 by repairing and grinding the first curved prism assembly trimming pad 22 to finish the adjustment of the rotating angle of the first curved prism assembly 2;

the curved prism assembly trimming pad 22 is trimmed again, so that the height of the curved prism assembly 2 is adjusted when the Z2 is ensured to be Z3 to be Z1;

step three, installing and adjusting a curved surface reflecting prism assembly 3;

mounting the first curved surface reflection prism assembly 3 on the base plate 9, measuring the angle between the front reference surface of the first curved surface reflection prism 31 and the mounting surface of the base plate 9 by adopting a three-coordinate measuring instrument, and ensuring that the front reference surface of the first curved surface reflection prism 31 is vertical to the mounting plane of the base plate 9 by repairing and grinding the first curved surface reflection prism assembly trimming pad 32 to finish the adjustment of the pitching angle of the first curved surface reflection prism assembly 3;

measuring a sphere center height coordinate Z4 of the front surface C4 and a sphere center height Z5 of the rear surface C5 of the first curved surface reflection prism assembly 3 by using a three-coordinate measuring instrument, and ensuring that Z4 is Z5 by repairing and grinding the first curved surface reflection prism assembly trimming pad 32 to complete the adjustment of the rotation angle of the first curved surface reflection prism assembly 3;

the trimming pad 32 of the first curved reflection prism assembly is trimmed again, and the height adjustment of the first curved reflection prism assembly 3 is completed by ensuring that the Z4 is equal to Z5 is equal to Z1;

step four, installing and adjusting a second curved surface prism assembly 5 and a second curved surface reflection prism assembly 6;

similarly, referring to the third step or the fourth step, the adjustment of the pitch angle, the rotation angle and the Z-direction height of the second curved prism assembly 5, the second curved reflection prism assembly 6 and the folding axis mirror assembly 7 is completed;

acquiring the spherical center coordinates of the spherical surfaces of the optical elements;

as shown in fig. 4, a system coordinate system is established, the system coordinate system uses the spherical center of the convex surface C1 of the secondary reflector 41 as the origin of coordinates, uses the central axis of the secondary reflector 41 as the X axis, uses the Z axis as the vertical height direction, and uses the Y axis perpendicular to the X axis, which can be determined by the right-hand rule; determining the spherical center coordinates of the spherical surfaces of the optical elements according to the design values;

sixthly, fixing the curved surface prism assembly 2;

placing a metal ball at the theoretical center of sphere position (8.81, 10.7) of the front surface C2 of the curved surface prism assembly 2, focusing a point source microscope PSM on the center of the metal ball, recording the barycentric coordinate D2 of an image point on the image surface of the point source microscope, removing the metal ball, adjusting the X-direction displacement, the Y-direction displacement and the azimuth angle of the curved surface prism assembly 2 through the screw through hole quantity, enabling the image point coordinates D3 of a light beam emitted by the point source microscope to be consistent with the D2 through the imaging of the curved surface prism assembly 21, and fixing the curved surface prism assembly 2;

seventhly, fixing the curved surface prism I21, the curved surface reflecting prism II assembly 6 and the folding axis mirror assembly 7;

similarly, referring to the sixth step, the adjustment of the X-direction displacement, the Y-direction displacement and the azimuth angle of the first curved surface reflection prism component 3, the second curved surface prism component 5, the second curved surface reflection prism component 6 and the folding axis mirror component 7 is completed;

step eight, completing the installation and adjustment of the system;

the encoding assembly is installed on a base plate 9, a detector 8 is placed at the image surface of the system, the detector 8 is installed on the base plate 9 through a detector support 81, a star point plate is installed on the encoding assembly, a star point image is observed through a point source microscope, the encoding assembly is finely adjusted to the optimal imaging quality, and the assembly and adjustment of the system are completed.

The adjusting method can realize the six-degree-of-freedom adjustment of each off-axis spherical mirror through the mutual matching of the three-coordinate measuring instrument and the point source microscope, and further can realize the system adjustment of the off-axis prism dispersion spectrometer with high speed and high precision.

The method converts the installation and debugging of the optical system into various simple geometric relations such as angle relation and adjustment of coordinates of a spherical center point, overcomes the equipment complexity of the traditional installation and debugging method by utilizing an imaging spectrogram, reduces the technical requirements on assembly personnel, and greatly reduces the installation and debugging difficulty.

The adjusting method can reduce the difficulty of structural design of the optical instrument, and has the advantages of low adjusting cost, short adjusting time, high adjusting precision and simple required adjusting equipment.