CN117309329A - Full-space detection device and method for optical element - Google Patents

Abstract

The invention provides an optical element full-space detection device and method, which belongs to the field of optical element detection. The device includes an optical path unit and a mechanical unit, wherein: the light source component of the optical path unit is used to provide incident light; the reflection detection component is arranged in the area to be tested. The reflective side of the optical element; the transmission detection component is set on the transmission side of the optical element to be measured; the sample movement platform of the mechanical unit is used to fix the optical element to be measured and drive it to move; the light source movement platform is used to drive the light source component to rotate; the detector hemisphere The motion platform is configured to synchronously drive the reflection detection component and the transmission detection component to move within their respective hemispheres. The present invention can effectively improve the accuracy of detection by adding an information source, and by setting up a mechanical unit, it can realize full-space detection of reflected light and transmitted light, thereby obtaining more light intensity information, thereby further improving the accuracy of detection. and measurement efficiency.

Description

A device and method for full-space detection of optical components

Technical field

The invention belongs to the field of optical element detection, and more specifically, relates to an optical element full-space detection device and method.

Background technique

Optical elements represented by fused quartz and single crystal silicon are used more and more widely. During the processing of optical elements, the surface/subsurface defects introduced will strengthen the light field caused by interference and crack impurities to enhance the laser absorption capacity of optical materials. These three aspects, including the reduction of material mechanical properties, simultaneously affect the defect sensitivity of optical elements, thereby causing macroscopic defects in optical elements and reducing the performance of optical elements.

At present, light scattering method is usually used for non-destructive testing of optical components, that is, laser scattering technology is used to measure defects and surface contaminants, and polarization technology is used to distinguish defects, particle contaminants and surface roughness. However, the detectors in the existing technology are fixed and can only measure scattered light and cannot detect the light intensity distribution of the entire space, which in turn causes problems of poor detection accuracy and low efficiency.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the present invention is to provide an optical element full-space detection device and method, aiming to solve the problem that the existing light scattering detection device cannot detect the entire space light intensity distribution.

In order to achieve the above objects, according to one aspect of the present invention, a full-space detection device for optical elements is provided. The device includes an optical path unit and a mechanical unit, wherein:

The optical path unit includes a light source component, a reflection detection component and a transmission detection component. The light source component is used to provide incident light to the optical element to be tested to generate reflected light and transmitted light; the reflection detection component is arranged on the optical element to be tested. The reflection side is used to collect the light intensity information of the reflected light; the transmission detection component is arranged on the transmission side of the optical element to be measured, and is used to collect the light intensity information of the transmitted light;

The mechanical unit includes a sample movement platform, a light source movement platform and a detector hemisphere movement platform. The sample movement platform is used to fix the optical element to be measured and drive it to move; the light source movement platform is arranged in front of the sample movement platform and It is connected with the light source component to drive the light source component to rotate; the detector hemispheric motion platform is arranged behind the sample motion platform and is connected with the reflection detection component and the transmission detection component to synchronously drive the reflection detection component and the transmission detection component in their respective The movement within the hemisphere enables full-space detection of reflected light and transmitted light.

As a further preference, the optical element full-space detection device also includes a darkroom cover, which is arranged outside the optical path unit and the mechanical unit for forming a darkroom environment, and the inner wall of the darkroom cover is provided with a light-absorbing structure. To absorb stray light.

As a further preference, the light source assembly includes a laser and a spot adjustment structure connected in sequence, the laser is used to generate a laser spot, and the spot adjustment structure is used to adjust the laser spot to form incident light.

As a further preference, the light spot adjustment structure includes a polarizer, a filter, a collimating lens and an incident diaphragm connected in sequence along the light propagation direction.

As a further preference, the reflection detection component includes a first analyzer, a first diaphragm and a first photomultiplier tube connected in sequence along the light propagation direction.

As a further preference, the transmission detection component includes a second analyzer, a second aperture and a second photomultiplier tube connected in sequence along the light propagation direction.

As a further preference, the sample movement platform includes a sample clamp and a sample XY-axis moving structure, wherein the sample clamp is used to place the optical element to be tested, and the sample XY-axis moving structure is connected with the sample clamp to drive the optical element to be tested. The element moves along the X-axis and Y-axis, thereby changing the irradiation position of the incident light.

As a further preference, the light source movement platform includes a first support rod and a C-axis rotation structure of the light source, wherein the first support rod is placed vertically, its upper end is connected to the light source assembly, and its lower end is connected to the C-axis rotation structure of the light source; The C-axis rotation structure of the light source is fixed on the bottom surface and is used to drive the light source assembly to rotate around the Z-axis.

As a further preference, the detector hemispheric motion platform includes a second support rod, an L-shaped connecting rod, a detector B-axis rotation structure, a detector C-axis rotation structure and a cross bar, wherein the second support rod is vertically fixed On the bottom surface; one end of the L-shaped connecting rod is connected to the second support rod through the B-axis rotation structure of the detector, and the other end is connected to the cross bar through the C-axis rotation structure of the detector; one end of the cross bar is connected to the inclined The reflection detection component is connected, and the other end is connected with the transmission detection component.

According to another aspect of the present invention, a method for full-space detection of optical elements is provided. The method adopts the above-mentioned full-space detection device for optical elements and specifically includes the following steps:

S1 starts the light source component and places the optical element to be tested, then turns on the reflection detection component and transmission detection component;

S2 uses the light source movement platform to drive the light source component to rotate to adjust the incident angle of the incident light. At the same time, it uses the detector hemisphere movement platform to drive the reflection detection component and transmission detection component to rotate at the same angle to collect the light intensity information of reflected light and transmitted light.

S3 Repeat step S2 until the incident angle covers the set range, thereby completing the detection at the current light spot;

S4 uses the sample movement platform to drive the optical element under test to move a preset distance to the next light spot, and then repeats steps S2 and S3 until the incident light covers the optical element under test, and obtains the surface of the optical element under test based on the collected light intensity information. Defects and contaminants.

Generally speaking, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

1. By arranging a reflection detection component and a transmission detection component, the present invention can realize synchronous detection of reflected light and transmitted light. Compared with measuring reflected light alone, it adds an information source and can effectively improve the accuracy of surface defect and contaminant detection. , at the same time, the present invention can realize full-space detection of reflected light and transmitted light by setting up a mechanical unit. Compared with the existing technology with a fixed detector, it can obtain more light intensity information, thereby further improving the detection accuracy and measurement efficiency. ;

2. In particular, the present invention can effectively absorb stray light in the space and reduce the influence of the stray light detection light path by arranging a darkroom cover and a light-absorbing structure on its inner wall;

3. At the same time, the present invention can further improve the accuracy of detection by optimizing the structures of the light source component, reflection detection component and transmission detection component;

4. In addition, by optimizing the structures of the sample movement platform, the light source movement platform and the detector hemisphere movement platform, the present invention can realize the coordinated movement of the optical element to be measured, the light source assembly, the reflection detection component and the transmission detection component, and solve the problem of rotation. The problem of time imbalance can be improved while improving detection accuracy while further reducing detection time, thereby effectively improving detection efficiency.

Description of drawings

Figure 1 is a schematic structural diagram of an optical element full-space detection device provided by an embodiment of the present invention;

Figure 2 is a schematic optical path diagram of a full-space detection device for optical elements provided by an embodiment of the present invention;

Figure 3 is the inner wall structure of the darkroom cover in the optical element full-space detection device provided by the embodiment of the present invention;

Figure 4 is a flow chart of a full-space detection method for optical elements provided by an embodiment of the present invention;

Figure 5 is a schematic diagram of the light intensity collection scheme in the full-space detection method of optical elements provided by the embodiment of the present invention.

Throughout the drawings, the same reference numbers refer to the same elements or structures, wherein:

101-light source C-axis rotation structure, 102-first support rod, 103-second support rod, 104-sample clamp, 105-detector C-axis rotation structure, 106-detector B-axis rotation structure, 107-sample XY axis Moving structure, 108-L-shaped connecting rod, 109-cross bar, 200-optical element to be tested, 300-spot adjustment structure, 301-laser, 302-polarizer, 303-filter, 304-collimating mirror, 305 -Incidence diaphragm, 310-Reflection detection component, 311-First photomultiplier tube, 312-First diaphragm, 313-First analyzer, 320-Transmission detection component, 321-Second photomultiplier tube, 322- The second diaphragm, 323-second polarizer, 400-darkroom cover, 401-light absorption structure.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention.

As shown in Figures 1 and 2, according to one aspect of the present invention, a full-space detection device for optical elements is provided. The device includes an optical path unit and a mechanical unit, wherein:

The optical path unit includes a light source component, a reflection detection component 310 and a transmission detection component 320. The light source component is used to generate collimated parallel light for defect detection, that is, incident light, to illuminate the surface of the optical element 200 to be tested. After passing through the rough surface and defects, The polarization state of the incident light changes and generates reflected light and transmitted light, which is used to distinguish surface roughness and defects; the reflection detection component 310 is provided on the reflection side of the optical element 200 to be tested, and is used to collect the light intensity information of the reflected light and identify roughness. degree signal and defect signal; the transmission detection component 320 is arranged on the transmission side of the optical element 200 to be tested, and is used to collect the light intensity information of the transmitted light and identify the roughness signal and defect signal;

Taking the fixed plane of the mechanical unit as the XY horizontal plane, and taking the direction in which the reflection detection component 310 points to the transmission detection component 320 as the Y axis, an XYZ axis coordinate system is established. The mechanical unit includes a sample movement platform, a light source movement platform and a detector hemisphere movement platform. The sample movement platform includes a sample clamp 104 and a sample XY-axis moving structure 107. The sample clamp 104 is used to place the optical element 200 to be tested. The sample XY-axis moving structure 107 is connected to the sample clamp 104 to drive the optical element 200 to be tested along the X-axis. , moves in the direction of the Y-axis, thereby changing the irradiation position of the incident light; the sample XY-axis moving structure 107 can use a manual slide, and use manual adjustment to drive the movement of the optical element 200 to be tested;

The light source movement platform is arranged in front of the sample movement platform and is connected to the light source assembly. It includes a first support rod 102 and a light source C-axis rotation structure 101. The first support rod 102 is placed vertically, its upper end is connected to the light source assembly, and its lower end is connected to the light source assembly. The light source C-axis rotation structure 101 is connected; the light source C-axis rotation structure 101 is fixed on the bottom surface and is used to drive the light source assembly to rotate around the Z-axis, thereby changing the incident angle of the incident light while the incident radius of the incident light remains unchanged;

The detector hemispheric motion platform is arranged behind the sample motion platform and connected to the reflection detection component 310 and the transmission detection component 320. It includes a second support rod 103, an L-shaped link 108, a detector B-axis rotation structure 106, and a detector C. The shaft rotation structure 105 and the crossbar 109, the second support rod 103 are vertically fixed on the bottom surface; one end of the L-shaped connecting rod 108 is connected to the second support rod 103 through the detector B-axis rotation structure 106, so that the L-shaped connecting rod 108 The detector B-axis rotation structure 106 rotates around the Y-axis, and its other end is connected to the crossbar 109 through the detector C-axis rotation structure 105, so that the detector C-axis rotation structure 105 drives the crossbar 109 to rotate around the Z-axis. ; One end of the crossbar 109 is connected to the inclined reflection detection assembly 310, and the other end is connected to the transmission detection assembly 320, so that under the joint action of the detector B-axis rotation structure 106 and the detector C-axis rotation structure 105, the reflection is synchronously driven The detection component 310 and the transmission detection component 320 move within their respective hemispheres to achieve full-space detection of reflected light and transmitted light; the axis of the reflection detection component 310 forms a certain angle with the axis of the incident light to avoid the detection process of the reflection detection component 310 effect on incident light.

Further, as shown in Figure 3, the optical element full-space detection device also includes a darkroom cover 400. The darkroom cover 400 is provided outside the optical path unit and the mechanical unit to form a darkroom environment. The inner wall of the darkroom cover 400 is provided with a light-absorbing structure 401, and the surface of the light-absorbing structure 401 is coated with a light-absorbing black coating to absorb stray light through multiple reflections of the light-absorbing structure 401 and the light-absorbing black coating to avoid stray light reflection. noise, thereby reducing the impact of stray light on measurement results. Preferably, the light-absorbing structure 401 adopts an isosceles triangle microstructure.

Further, the light source component includes a laser 301 and a spot adjustment structure 300 connected in sequence, which are used to generate incident light with different spot radii and polarization states. The laser 301 is used to generate a laser spot of a specific wavelength, preferably a 532nm filter laser. The power The range can be adjusted within the range of 0 to 100mW; the spot adjustment structure 300 is used to adjust the laser spot to form incident light. The spot adjustment structure 300 includes a polarizer 302, a filter 303, and a collimator connected in sequence along the direction of light propagation. Mirror 304 and incident diaphragm 305, in which the polarizer 302 is used to generate S or P polarized light, and the collimating mirror 304 and the incident diaphragm 305 are used to realize the incidence of polarized parallel light, which can remove the roughness of the optical element 200 to be measured. And then use the analyzer to detect the change of polarization state after defect scattering. Among them, the polarizer 302 is mainly used to avoid the impact of surface roughness on defect detection; the filter 303 is used to generate uniform laser light to avoid the impact of other wavelength laser incidence on the measurement results; the collimating mirror 304 is used to collimate the optical path to reduce The problem of scattered light caused by uneven light distribution of the light source improves the accuracy of detection; the incident diaphragm 305 is used to adjust the size of the laser spot that illuminates the surface of the optical element 200 to be tested, so as to be suitable for different optical element sizes.

Further, the reflection detection component 310 includes a first analyzer 313, a first diaphragm 312 and a first photomultiplier tube 311 that are connected in sequence along the direction of light propagation, and the transmission detection component 320 includes a second analyzer that is connected in sequence along the direction of light propagation. 323, the second aperture 322 and the second photomultiplier tube 321. Among them, the first analyzer 313 and the second analyzer 323 interact with the polarizer 302 to detect specific scattering signals, which can remove the polarization state of the incident light and achieve the removal of surface roughness signals; through the first photoelectric multiplication The tube 311 and the second photomultiplier tube 321 directly detect the distribution state of the scattered light intensity caused by the defects, and adjust the size of the detection light spot with the help of the first aperture 312 and the second aperture 322 . In order to avoid the problem of defects caused by excessive light intensity when the first photomultiplier tube 311 and the second photomultiplier tube 321 directly detect reflected light and transmitted light, the photomultiplier tube protection program and circuit design can be set accordingly. At the same time, in order to reduce the impact of stray light on photomultiplication, the length of the light receiving ports of the first photomultiplier tube 311 and the second photomultiplier tube 321 can be extended, and a black conductive coating can be applied to the surface and inner surface of the entire photomultiplier tube. , thereby achieving stray light absorption and electromagnetic shielding. The light signal detected by the first photomultiplier tube 311 and the second photomultiplier tube 321 is obtained by using a data collector to obtain the light intensity signal, and the light scattering signal is collected by using weak signal processing means.

During the test, the incident light irradiates the surface of the optical element 200 to be tested, part of the surface is reflected, and part is transmitted through the optical element 200 to be tested. The surface roughness of the optical element 200 to be tested has no effect on the polarization state of the incident light. However, Defects and surface contaminants will cause changes in the light scattering state. The first analyzer 313 and the second analyzer 323 remove the same polarization state as the incident light, and detect the light intensity distribution of the change in polarization state caused by defects and surface contaminants. .

As shown in Figure 4, according to another aspect of the present invention, a method for full-space detection of optical elements is provided, which method includes the following steps:

S1 starts the light source component and adjusts the polarization state of the incident light, then places the optical element 200 to be tested, finally turns on the reflection detection component 310 and the transmission detection component 320, and debugs the first photomultiplier tube 311 and the second photomultiplier tube 321;

S2 uses the light source movement platform to drive the light source component to rotate to adjust the incident angle of the incident light, and at the same time uses the detector hemisphere movement platform to drive the reflection detection component 310 and the transmission detection component 320 to rotate at the same angle to collect the light intensity information of the reflected light and transmitted light;

S3 Repeat step S2 until the incident angle covers the set range to complete the detection at the current light spot;

S4 uses the sample movement platform to drive the optical element 200 to be tested to move a preset distance to the next light spot, and then repeats steps S2 and S3 until the incident light covers the optical element 200 to be tested, and obtains the optical element to be tested based on the collected light intensity information. 200 surface defects and contaminants.

Further, in step S1, the equipment is first debugged before use, mainly focusing on factors such as the polarization state of the incident light, the diameter of the incident light spot, and the defect detection environment; after the initial debugging of the equipment is completed, the laser 301 is started, and there is no external noise signal at a constant temperature. In the case of interference, stable operation for a period of time ensures that the entire device enters a stable operating state.

Further, in step S2, the initial incident angle of the incident light is set to 0°. At this time, the light intensity detected by the first photomultiplier tube 311 and the second photomultiplier tube 321 has a maximum value, and the distribution of the maximum light intensity is detected, Set a high and low range to achieve high-sensitivity measurement of defective light intensity signals while ensuring the safety of the photomultiplier tube. As shown in Figure 5, determine whether the intensity of the detected light intensity signal exceeds the peak light intensity. If so, turn on the strong light protection and disconnect the light intensity collection. If not, determine whether it exceeds the low-range measurement range. If so, adjust the to the high-level light intensity collection circuit. If not, adjust to the low-level light intensity collection circuit.

Further, in step S3, common detection methods such as white light scattering are first used to detect surface defect morphology, the detected surface defect morphology is compared with that detected by light intensity distribution, and the spatial distribution of defects is compared with the correspondence between the real defect morphology Establish a scattering matrix library to determine the defect morphology with the help of the scattering matrix library and the collected light intensity information.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements, etc., made within the spirit and principles of the present invention, All should be included in the protection scope of the present invention.

Claims (10)

1. An optical element full-space detection device is characterized by comprising an optical path unit and a mechanical unit, wherein:

the light path unit comprises a light source assembly, a reflection detection assembly (310) and a transmission detection assembly (320), wherein the light source assembly is used for providing incident light to the optical element (200) to be detected so as to generate reflected light and transmitted light; the reflection detection component (310) is arranged on the reflection side of the optical element (200) to be detected and is used for collecting the light intensity information of the reflected light; the transmission detection component (320) is arranged on the transmission side of the optical element (200) to be detected and is used for collecting the light intensity information of the transmitted light;

the mechanical unit comprises a sample motion platform, a light source motion platform and a detector hemispherical motion platform, wherein the sample motion platform is used for fixing an optical element (200) to be detected and driving the optical element to move; the light source moving platform is arranged in front of the sample moving platform and is connected with the light source assembly so as to drive the light source assembly to rotate; the hemispherical detector motion platform is arranged behind the sample motion platform and is connected with the reflection detection assembly (310) and the transmission detection assembly (320) so as to synchronously drive the reflection detection assembly (310) and the transmission detection assembly (320) to move in respective hemispheres, thereby realizing full-space detection of reflected light and transmitted light.

2. The optical element full-space detection device according to claim 1, further comprising a darkroom cover (400), the darkroom cover (400) being disposed outside the optical path unit and the mechanical unit for forming a darkroom environment, and an inner wall of the darkroom cover (400) being provided with a light absorbing structure (401) for absorbing stray light.

3. The optical element full space detection device according to claim 1, wherein the light source assembly comprises a laser (301) and a spot adjusting structure (300) connected in sequence, the laser (301) being configured to generate a laser spot, the spot adjusting structure (300) being configured to adjust the laser spot to form incident light.

4. A full-space optical element detection device according to claim 3, characterized in that the spot-adjusting structure (300) comprises a polarizer (302), a filter (303), a collimator mirror (304) and an entrance diaphragm (305) connected in sequence in the direction of light propagation.

5. The optical element full-space detection device according to claim 1, wherein the reflection detection assembly (310) includes a first analyzer (313), a first diaphragm (312), and a first photomultiplier tube (311) connected in order along a light propagation direction.

6. The optical element full-space detection device according to claim 1, wherein the transmission detection assembly (320) includes a second analyzer (323), a second diaphragm (322), and a second photomultiplier (321) connected in order along a light propagation direction.

7. The optical element full-space detection device according to claim 1, wherein the sample motion platform comprises a sample clamp (104) and a sample XY axis moving structure (107), wherein the sample clamp (104) is used for placing the optical element (200) to be detected, and the sample XY axis moving structure (107) is connected with the sample clamp (104) to drive the optical element (200) to be detected to move along the directions of an X axis and a Y axis, so as to change the irradiation position of incident light.

8. The optical element full-space detection device according to claim 1, wherein the light source moving platform comprises a first supporting rod (102) and a light source C-axis rotating structure (101), wherein the first supporting rod (102) is vertically arranged, the upper end of the first supporting rod is connected with a light source assembly, and the lower end of the first supporting rod is connected with the light source C-axis rotating structure (101); the light source C-axis rotating structure (101) is fixed on the bottom surface and is used for driving the light source assembly to rotate around the Z axis.

9. The full-space optical element detection device according to any one of claims 1 to 8, wherein the hemispherical detector motion platform comprises a second support rod (103), an L-shaped connecting rod (108), a detector B-axis rotation structure (106), a detector C-axis rotation structure (105) and a cross rod (109), wherein the second support rod (103) is vertically fixed on a bottom surface; one end of the L-shaped connecting rod (108) is connected with the second supporting rod (103) through the detector B-axis rotating structure (106), and the other end of the L-shaped connecting rod is connected with the cross rod (109) through the detector C-axis rotating structure (105); one end of the cross bar (109) is connected with an inclined reflection detection component (310), and the other end of the cross bar is connected with a transmission detection component (320).

10. An optical element full-space detection method, characterized in that the method adopts the optical element full-space detection device as claimed in any one of claims 1 to 9, and specifically comprises the following steps:

s1, starting a light source assembly, placing an optical element (200) to be tested, and then starting a reflection detection assembly (310) and a transmission detection assembly (320);

s2, driving a light source assembly to rotate by utilizing a light source moving platform to adjust the incident angle of incident light, and simultaneously driving a reflection detection assembly (310) and a transmission detection assembly (320) to rotate by the same angle by utilizing a detector hemispherical moving platform to acquire light intensity information of the reflected light and the transmitted light;

s3, repeating the step S2 until the incident angle covers the set range, so as to finish the detection of the current light spot;

s4, driving the optical element (200) to be detected to move a preset distance to the position of the next light spot by using the sample motion platform, and repeating the steps S2 and S3 until the incident light covers the optical element (200) to be detected, and obtaining the surface defect and the pollutant of the optical element (200) to be detected according to the collected light intensity information.