CN116338970A

CN116338970A - Method for obtaining high-power, high-uniformity, high-collimation and ultra-narrow band line light source

Info

Publication number: CN116338970A
Application number: CN202211741169.3A
Authority: CN
Inventors: 李青岩; 龚海; 魏新和; 顾海鹏; 杨彦琳; 陈俊秀
Original assignee: Huzhou Institute of Zhejiang University
Current assignee: Huzhou Institute of Zhejiang University
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-06-27

Abstract

The invention discloses a method for obtaining a high-power, high-uniformity, high-collimation and ultra-narrow band line light source, which comprises the following steps: the system light source outputs a parallel laser beam; the light beam is incident to the Bawil prism to realize expansion in the vertical direction; the expanded light beam is incident to a cylindrical mirror, and the expanded light beam is collimated, so that an output light beam is parallel light; the output long-strip parallel light is emitted to another long Jiao Zhumian mirror, and the long-strip parallel light is converged; the converging light beam is emitted to a short-focus cylindrical mirror, and the emergent light beam is corrected to be a parallel light beam, so that a high-power, high-uniformity, high-collimation and ultra-narrow-band linear light source is obtained; the detectors are placed at different locations to see the quality and illumination of the outgoing beam at different locations in the system. The invention utilizes reasonable combination of the Bawil prism and the aspheric plano-convex cylindrical lens with different focal lengths to obtain a beam of high-power, high-uniformity, high-collimation and ultra-narrow-band linear light source, and can be applied to detection of high-precision optical elements and chips.

Description

Method for obtaining high-power, high-uniformity, high-collimation and ultra-narrow band line light source

Technical Field

The invention relates to a method for obtaining a high-power, high-uniformity, high-collimation and ultra-narrow band line light source, belonging to the technical field of optical high-precision detection and illumination.

Background

For high-precision optical element and chip detection, the traditional method is a visual method, detection is carried out through naked eyes and a microscope, and the quality and defects of the detection target are judged according to past experience. The method is simple to operate and has low requirements on equipment. However, the method has the defects of low detection efficiency, strong subjectivity, lack of unified standards, low detection precision, low detection speed and the like. In order to overcome the defects, the detection element can be scanned by using a high-performance linear light source, and the linear array industrial camera can be used for shooting, so that high-speed large-breadth and high-precision detection can be realized. The higher the detection accuracy of the system, the higher the beam quality requirements for the line source.

At present, the existing linear light sources mostly adopt LED light sources as basic light sources, the linear light sources are formed by linear arrangement, and then collimation is carried out through a collimation lens. However, since the outgoing light of the LED light source is disordered, the divergence angle of the light beam passing through the collimating lens is still very large, the energy distribution of the light beam is uneven, and the width of the light source is relatively large. If the applied scene object distance is far, the light beam is very divergent, and the light beam energy cannot meet the application requirement. For a scene needing high-precision display and detection, the brightness of the light source irradiated to a target is uneven, and the high-precision requirement of a system cannot be met.

In summary, although the present linear light source has been widely used in various fields, the quality of the light beam is improved. But still has the defects of large beam divergence degree, uneven light spot distribution, large beam line width, weak energy and the like. In addition, the traditional detection method has the defects of low detection efficiency, strong subjectivity, lack of unified standards, low detection precision, low detection speed and the like.

Disclosure of Invention

The invention provides a method for obtaining a high-power, high-uniformity, high-collimation and ultra-narrow band line light source, which aims to solve the problems of large beam divergence degree, uneven light spot distribution, large beam linewidth, weak energy and the like of the traditional line light source.

The invention can be realized by the following technical scheme:

a method of obtaining a high power, high uniformity, high collimation, ultra-narrow band line light source, comprising the steps of:

step one, a system light source outputs a parallel laser beam;

step two, the light beam is incident to the Bawil prism to realize expansion in the vertical direction;

thirdly, the expanded light beam is incident to a cylindrical mirror, and the expanded light beam is collimated, so that an output light beam is parallel light;

step four, the output long parallel light is emitted to another long Jiao Zhumian mirror, and the long parallel light is converged;

step five, the converged light beam is emitted to a short-focus cylindrical mirror, and the emitted light beam is corrected to be a parallel light beam, so that a high-power, high-uniformity, high-collimation and ultra-narrow-band linear light source is obtained;

and step six, placing detectors at different positions to check the quality and illumination of the emergent light beams at different positions of the system.

Further, the light source in the first step is a high-performance white laser light source, the diameter of a light spot is 2mm, and the output light beam is approximately parallel light.

Further, the powell lens in the second step has a ridge shape, the ridge angle is 60 °, the prism material is N-SF6, the refractive index is 1.805, and the abbe number is 25.36.

Further, the cylindrical lenses in the third and fourth steps are high-order aspheric plano-convex cylindrical lenses with a diameter of 50mm, a focal length of 40mm, a lens material of S-LAH64, a refractive index of 1.788 and an Abbe number of 47.49.

Further, the cylindrical mirror in the third step is horizontally placed, and the cylindrical mirror in the fourth step is vertically placed.

Further, the cylindrical lens in the fifth step is a high-order aspheric plano-convex cylindrical lens with a diameter of 10mm, a focal length of 8mm, a lens material of S-LAH64, a refractive index of 1.788 and an Abbe number of 47.49.

Further, the cylindrical mirrors in the fifth step are vertically arranged, and the two cylindrical mirrors in the fourth step and the fifth step form a kepler system, and the beam compression ratio is 5.

Further, in the sixth step, the detector is a rectangular detector, and is used for observing the quality of the outgoing beam.

Advantageous effects

The invention utilizes reasonable combination of the Bawil prism and the aspheric plano-convex cylindrical lens with different focal lengths to obtain a beam of high-power, high-uniformity, high-collimation and ultra-narrow-band linear light source, and can be applied to detection of high-precision optical elements and chips. The line width of the line light source can be further compressed by increasing the number of the long and short focal cylindrical lenses, and the energy density of the line light source can be increased. The light source adopts a laser source to ensure high power of the linear light source. The Zemax optical design software is used for analyzing the design result, and the result shows that the linear light source compressed by the Kepler system is parallel light, the light beam distribution is very uniform, the light beam linewidth is 600um, the actual requirement can be well met, and the high resolution and high precision performance of the detection and display system are ensured.

Drawings

FIG. 1 is a diagram of the light path of an expanded beam of a Powell prism;

FIG. 2 is a schematic view of the overall optical path of the system of the present invention;

FIG. 3 is a graph of beam shape and illumination at various locations in the system;

fig. 4 is a schematic view of the compact optical path of the present invention.

Detailed Description

Other advantages and effects of the present invention will become readily apparent to those skilled in the art from the following disclosure, when considered in light of the following detailed description of the invention.

Example 1

1-3, a method for obtaining a high power, high uniformity, high collimation, ultra-narrow band line light source in this embodiment, as shown in FIG. 2, includes the following steps;

step one, a system light source 101 outputs a parallel laser beam;

step two, the light beam is incident to the Baowel prism 102 to realize expansion in the vertical direction;

step three, the expanded light beam is incident to a cylindrical mirror 103, and the expanded light beam is collimated, so that an output light beam is parallel light;

step four, the output long parallel light is emitted to another long Jiao Zhumian mirror 104, the long Jiao Zhumian mirror 104 rotates 90 degrees relative to the cylindrical mirror 103, and the long parallel light is converged;

step five, the converged light beam is emitted to a short-focus cylindrical mirror 105, and the emitted light beam is corrected to be a parallel light beam, so that a high-power, high-uniformity, high-collimation and ultra-narrow-band linear light source is obtained;

and step six, respectively placing

detectors

106, 107 and 108 at different positions to check the quality and illumination of the emergent light beams at different positions of the system.

The method is further described by combining design principles and design processes:

as shown in fig. 1, which shows the light path diagram of the expanded beam of the powell lens, the powell lens expands a circular beam in one direction, and the outgoing beam is converted into a linear beam which diverges in the expansion direction. The beam is collimated by an aspherical cylindrical mirror into a strip beam having the same width as the original laser beam. And then the collimated long-strip line light beam can be subjected to multiple compression through a group of cylindrical mirror systems with Kepler structures, and finally a very narrow-band line light beam with high collimation degree, high power and high uniformity is obtained.

The designed system architecture was analyzed using the optical system design software Zemax, and fig. 3 is a graph of beam shape and illumination at various locations in the system. It can be seen that the line beam finally emitted by the system has uniform energy distribution, high collimation and line width of 600um.

Example 2

The present embodiment is a compact system architecture that achieves high power, high uniformity, high collimation, and ultra-narrow band line sources.

In order to make the system more compact, a reflector is added to the method for obtaining the high-power, high-uniformity, high-collimation and ultra-narrow band line light source to carry out light path deflection, and the kepler structure system is converted into a Galileo system structure, as shown in fig. 4.

Mirrors

109, 110, 111, 112, 113, 114 are added to the system. The plano-convex short focal cylindrical mirror 105 is adjusted to the plano-concave short focal cylindrical mirror 115, so that the whole system is more compact and the system volume is smaller.

In actual operation, the number of the reflecting mirrors is not limited to 4, and the number of the reflecting mirrors can be increased or decreased according to actual needs, so that the system structure is more reasonable.

In practice, the cylindrical mirror in this example can be replaced with a combination of different diameters and focal lengths, thereby changing the compression ratio of the system to the line beam width.

The present invention is capable of other and further embodiments and its several details are capable of modification and variation in accordance with the present invention by those skilled in the art, without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for obtaining a high power, high uniformity, high collimation, ultra-narrow band line source comprising the steps of:

step one, a system light source outputs a parallel laser beam;

2. The method of claim 1, wherein the light source in the first step is a high-performance white laser light source, the spot diameter is 2mm, and the output beam is approximately parallel light.

3. The method of claim 1, wherein the powell lens of step two has a ridge shape with a ridge angle of 60 °, the prism material being N-SF6, the refractive index of 1.805, and the abbe number of 25.36.

4. The method of claim 1, wherein the cylindrical lenses of the third and fourth steps are high order aspheric plano-convex cylindrical lenses having a diameter of 50mm, a focal length of 40mm, a lens material of S-LAH64, a refractive index of 1.788, and an abbe number of 47.49.

5. The method of claim 1 or 4, wherein the cylindrical mirror is positioned horizontally in step three and the cylindrical mirror is positioned vertically in step four.

6. The method of claim 1, wherein the cylindrical lens in the fifth step is a high order aspherical plano-convex cylindrical lens having a diameter of 10mm, a focal length of 8mm, a lens material of S-LAH64, a refractive index of 1.788, and an abbe number of 47.49.

7. The method of claim 1 or 6, wherein the cylindrical mirrors in the fifth step are disposed vertically, and the two cylindrical mirrors in the fourth and fifth steps form a kepler system, and the beam compression ratio is 5.

8. The method of claim 1, wherein the detector in step six is a rectangular detector for observing the outgoing beam quality.