A device and method for detecting spectral and polarization performance of micro-filters

Abstract

The application discloses a detection device and method for micro filter spectral performance and polarization performance, solves the problems of large detection spot size of the existing filter detection method, difficulty in adapting to micro filters, or insufficient detection capacity and inaccurate detection results, and specifically comprises a stage, a light source and a rotatable polarizer arranged in the stage, a detection unit arranged above the stage, and an industrial computer electrically connected with the light source, the rotatable polarizer and the detection unit; the detection device and method adopt an imaging detection mode, can magnify and image a micro filter region to a detector, and can realize direct detection on a 0.1mm-10mm micro filter or a filter array sub-channel.

Description

Technical Field

[0001] This invention relates to microfilters, and more specifically to a device and method for detecting the spectral and polarization properties of microfilters. Background Technology

[0002] Optical filters are widely used in multispectral imaging, polarization imaging, spectral detection, miniature cameras, space optical payloads, and integrated optoelectronic detection systems. With the miniaturization and integration of optical systems, the size of optical filters has gradually decreased, forming micro-filters (ranging from 0.1 mm to 5 mm in size). Some micro-filters are directly integrated in array form into detector protective windows, focal plane arrays, or the front end of miniature optical systems.

[0003] In the aforementioned applications, parameters such as spectral transmittance, center wavelength, bandwidth, cutoff depth, channel consistency, polarization direction, and extinction ratio of the microfilter directly affect the spectral recognition accuracy and polarization measurement accuracy of the micro-optical system. Therefore, before the fabrication, assembly, and use of microfilters, it is necessary to accurately test their spectral and polarization performance.

[0004] Currently, traditional filter testing methods mainly include the following categories:

[0005] 1. Spectroscopic detection based on spectrophotometer;

[0006] Transmittance of conventional filters is typically measured using a spectrophotometer. This method is suitable for larger filter samples, but it has significant limitations for micro-filters: firstly, the detection spot of the spectrophotometer is usually large, making it difficult to accurately fall within the effective area of ​​the micro-filter; secondly, when micro-filters are arranged in an array, the spacing between different channels is small, and crosstalk can easily occur between adjacent channels, leading to inaccurate detection results.

[0007] 2. Indirect detection based on surcharged wafers;

[0008] In the process of optical filter coating, it is common to use a co-coated sample in the same furnace for spectral performance testing, and then use the test results of the co-coated sample to infer the performance of the actual optical filter. Although this method is convenient, it is an indirect test and cannot fully reflect the true state of the actual micro-filter. Especially when the actual filter is small in size, in a different position, on a different substrate, or has undergone subsequent processes such as cutting, bonding, and assembly, the results of the co-coated sample may deviate from those of the actual device.

[0009] 3. Separation of spectral detection and polarization detection;

[0010] For filters or polarization filter arrays with polarization selectivity, in addition to spectral performance, it is also necessary to detect the polarization direction and extinction ratio. Existing methods typically require the use of separate spectral detection equipment and polarization detection equipment, resulting in a complex detection process. Samples need to be repeatedly clamped and aligned, which can easily introduce positional and adjustment errors, leading to inaccurate detection results.

[0011] 4. Difficult to achieve multi-channel point-by-point detection;

[0012] For multispectral or polarization filter arrays, the different channels are small in size and closely arranged. Traditional detection methods are difficult to perform rapid, accurate, and channel-by-channel detection on each tiny channel, and it is also difficult to obtain spectral and polarization consistency between channels.

[0013] In summary, existing technologies for detecting miniature filters have the following problems:

[0014] (1) Traditional detection spot size is large and difficult to adapt to micro filters.

[0015] (2) Indirect testing based on the coating film cannot truly reflect the actual performance of the filter.

[0016] (3) Spectroscopic detection and polarization detection are usually separated, and the detection process is complicated.

[0017] (4) Insufficient ability to detect each channel of a multi-channel filter array.

[0018] (5) It is difficult to obtain information on the spatial position, spectral response and polarization response of the filter at the same time.

[0019] Therefore, there is an urgent need for a device that can directly target micro-filters and detect their spectral and polarization performance. Summary of the Invention

[0020] To address the technical problems of existing filter detection methods, such as large detection spot size making it difficult to adapt to micro-filters, insufficient detection capability, inaccurate detection results, complex detection process, and difficulty in simultaneously obtaining information on the spatial position, spectral response, and polarization response of the filter, this invention provides a device and method for detecting the spectral and polarization performance of micro-filters.

[0021] To achieve the above objectives, the present invention adopts the following technical solution:

[0022] A device for detecting the spectral and polarization properties of microfilters, wherein the microfilters have a size ranging from 0.1 mm to 10 mm; its special feature is that:

[0023] It includes a stage, a light source and a rotatable polarizer installed inside the stage, a detection unit installed above the stage, and an industrial control computer electrically connected to the light source, the rotatable polarizer and the detection unit respectively.

[0024] The stage includes a cylindrical frame, a first plate mounted on top of the frame, and a second plate mounted in the middle of the frame. The first plate has a first mounting hole in the middle for mounting a micro-filter to be tested. The second plate is parallel to the first plate, and has a second mounting hole in its middle corresponding to the first mounting hole. The rotatable polarizer is detachably mounted at the second mounting hole. The light source is located below the second plate and corresponds to the second mounting hole.

[0025] The active end of the detection unit corresponds to the first mounting through hole and is used to collect image data of the micro filter under test and send it to the industrial control computer.

[0026] The industrial control computer is electrically connected to the light source, the rotatable polarizer, and the detection unit. It is used to control the light source, the rotatable polarizer, and the detection unit, and to process and analyze the image data collected by the detection unit to obtain the spectral and polarization performance of the microfilter under test.

[0027] Furthermore, it also includes a two-dimensional displacement stage;

[0028] The two-dimensional displacement stage is located at the bottom of the loading frame and is electrically connected to the industrial control computer, used to move the loading stage under the control of the industrial control computer.

[0029] Furthermore, the detection unit includes a bracket mounted on one side of the load frame, an axial displacement stage mounted on the bracket, a detector disposed at the working end of the axial displacement stage, and a lens mounted at the working end of the detector;

[0030] Both the axial displacement stage and the detector are connected to the industrial control computer.

[0031] The axial displacement stage is used to drive the detector to move up and down.

[0032] The lens is oriented toward the first mounting through hole.

[0033] Furthermore, the first mounting through hole is a stepped through hole with the stepped surface facing upwards, and the stepped surface is used to support the micro filter to be tested.

[0034] Furthermore, the light source is a broadband adjustable light source with a spectral range of 400nm~2000nm.

[0035] Furthermore, the detector is a CMOS detector with a pixel size of 4.5μm×4.5μm and a pixel count of 5120×5120.

[0036] A method for detecting the spectral and polarization performance of microfilters, employing the aforementioned detection device for the spectral and polarization performance of microfilters, is characterized by comprising the following steps:

[0037] Step 1: Remove the rotatable polarizer from the second plate inside the stage, and place the micro filter to be tested at the first mounting through hole in the middle of the first plate.

[0038] Step 2: The industrial control computer controls the light source to switch to quasi-monochromatic light of different wavelengths, and gradually moves the stage, light source and micro-filter under test. The detection unit acquires spectral image information of the micro-filter under test at different positions under different quasi-monochromatic light and sends it to the industrial control computer.

[0039] Step 3: The industrial control computer obtains the spectral performance of the micro-filter under test based on the spectral image information;

[0040] Step 4: Fix the rotatable deflector to the second mounting through hole in the middle of the second carrier plate;

[0041] Step 5: The industrial control computer controls the rotatable polarizer to rotate to different polarization angles and controls the light source to switch to quasi-monochromatic light of different wavelengths. The stage, light source, rotatable polarizer and micro filter under test are moved step by step. The detection unit acquires polarization image information of the micro filter under test at different polarization angles, different quasi-monochromatic lights and different positions and sends it to the industrial control computer.

[0042] Step 6: The industrial control computer obtains the polarization performance of the microfilter under test based on the polarization image information, and completes the detection of the spectral performance and polarization performance of the microfilter.

[0043] Further, step 1 specifically involves removing the rotatable polarizer from the second carrier plate inside the stage, placing the micro-filter to be tested at the first mounting through hole in the middle of the first carrier plate, returning the two-dimensional displacement stage to zero, and adjusting the position of the detector and lens through the axial displacement stage so that the object-side focus of the lens is aligned with the upper surface of the micro-filter to be tested.

[0044] Further, step 2 specifically involves the industrial control computer controlling the light source to switch to quasi-monochromatic light of different wavelengths, and gradually moving the stage, light source and micro-filter under test through a two-dimensional displacement stage. The industrial control computer acquires spectral image information of the micro-filter under test at different positions under different quasi-monochromatic light through a detector and lens.

[0045] Further, step 5 specifically involves the industrial control computer controlling the rotatable polarizer to rotate to different polarization angles and controlling the light source to switch to quasi-monochromatic light of different wavelengths. The stage, light source, rotatable polarizer, and micro-filter under test are gradually moved by a two-dimensional displacement stage. The polarization image information of the micro-filter under test at different polarization angles, different quasi-monochromatic lights, and different positions is acquired by the detector and lens and sent to the industrial control computer.

[0046] The beneficial effects of this invention are:

[0047] 1. The present invention provides a device and method for detecting the spectral and polarization performance of micro-filters. It adopts an imaging detection method, which can magnify and image the micro-filter area onto the detector, and can realize the direct detection of micro-filters or filter array sub-channels of 0.1mm to 10mm.

[0048] 2. The present invention provides a device and method for detecting the spectral and polarization performance of micro-filters, which can directly detect the actual micro-filter body, avoid errors caused by different assembly and adjustment states between the coated film and the actual device, and improve detection accuracy and reliability.

[0049] 3. The present invention provides a device and method for detecting the spectral and polarization performance of micro-filters, which can complete the detection of spectral performance and polarization performance in the same optical path, reduce the repeated clamping of samples, and improve detection efficiency and consistency.

[0050] 4. The present invention provides a device and method for detecting the spectral and polarization performance of micro-filters, which can perform channel-by-channel detection on multispectral filter arrays, polarization filter arrays and composite filter arrays to obtain spectral and polarization consistency between different channels.

[0051] 5. The present invention provides a device and method for detecting the spectral and polarization performance of micro-filters. It does not require a complex optical path for spectral and polarization detection, nor does it require dispersing spectral and polarization detection into multiple sets of equipment. The overall structure is simple and easy to integrate into the process of small filter preparation, screening and assembly. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of an embodiment of the device for detecting the spectral and polarization performance of a micro-filter according to the present invention;

[0053] Figure 2 This is a schematic diagram of the installation structure of the stage, light source, rotatable polarizer and micro filter under test in an embodiment of the present invention;

[0054] Figure 3 This is a schematic diagram of the detection unit in an embodiment of the present invention.

[0055] The attached figures are labeled as follows:

[0056] 1. Stage; 11. Loading frame; 12. First loading plate; 121. First mounting through hole; 13. Second loading plate; 131. Second mounting through hole; 2. Light source; 3. Rotatable polarizer; 4. Detection unit; 41. Support; 42. Axial displacement stage; 43. Detector; 44. Lens; 5. Industrial computer; 6. Two-dimensional displacement stage; 7. Miniature filter to be tested. Detailed Implementation

[0057] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] This invention provides a device for detecting the spectral and polarization performance of microfilters, wherein the microfilter size ranges from 0.1 mm to 10 mm; for example... Figure 1 As shown, the detection device includes a stage 1, a light source 2 and a rotatable polarizer 3 disposed in the stage 1, a detection unit 4 disposed above the stage 1, an industrial control computer 5 electrically connected to the light source 2, the rotatable polarizer 3 and the detection unit 4 respectively, and a two-dimensional displacement stage 6.

[0059] like Figure 2 As shown, the stage 1 includes a cylindrical frame 11, a first mounting plate 12 mounted on the top of the frame 11, and a second mounting plate 13 mounted in the middle of the frame 11. The first mounting plate 12 has a first mounting through hole 121 in the middle. The first mounting through hole 121 is a stepped through hole with its stepped surface facing upwards, and the stepped surface is used to support the micro-filter 7 to be tested. The second mounting plate 13 is parallel to the first mounting plate 12, and has a second mounting through hole 131 in its middle that corresponds to the first mounting through hole 121. A rotatable polarizer 3 is detachably mounted at the second mounting through hole 131. The light source 2 is located below the second mounting plate 13 and corresponds to the second mounting through hole 131.

[0060] Light source 2 is a broadband adjustable light source with a spectral range of 400nm~2000nm, which can provide stable transmitted illumination.

[0061] like Figure 3As shown, the detection unit 4 is used to acquire image data of the micro-filter 7 under test and send it to the industrial control computer. The detection unit 4 includes a bracket 41 mounted on one side of the carrier frame 11, an axial displacement stage 42 mounted on the bracket 41, a detector 43 disposed at the working end of the axial displacement stage 42, and a lens 44 mounted at the working end of the detector 43. The lens 44 faces the first mounting through hole 121. The axial displacement stage 42 is used to drive the detector 43 to move up and down. The detector 43 used in this embodiment is a CMOS detector with a pixel size of 4.5μm×4.5μm, a pixel count of 5120×5120, and a Nyquist sampling frequency of [missing information]. .

[0062] The two-dimensional displacement stage 6 is located at the bottom of the loading frame 11 and is electrically connected to the industrial control computer 5. It is used to move the loading stage 1 under the control of the industrial control computer 5. The XY axis translational stroke of the two-dimensional displacement stage 6 is ±30 mm, the stage size is 150 mm × 162 mm, and the height is 12.7 mm.

[0063] The industrial control computer 5 is electrically connected to the light source 2, the rotatable polarizer 3, the axial displacement stage 42, the detector 43 and the two-dimensional displacement stage 6. It is used to control the light source 2, the rotatable polarizer 3 and the detector unit 4, and to process and analyze the image data to obtain the spectral performance and polarization performance of the micro-filter 7 under test.

[0064] The method for testing a microfilter under test using the aforementioned device for detecting the spectral and polarization performance of microfilters includes the following steps:

[0065] Step 1: Remove the rotatable polarizer 3 from the second carrier plate 13 inside the stage 1, place the micro filter 7 to be tested at the first mounting through hole 121 in the middle of the first carrier plate 12, return the two-dimensional displacement stage 6 to the zero position, and adjust the position of the detector 43 and the lens 44 through the axial displacement stage 42 so that the object-side focus of the lens 44 is aligned with the upper surface of the micro filter 7 to be tested.

[0066] Step 2: The industrial control computer 5 controls the light source 2 to switch to quasi-monochromatic light of different wavelengths, and gradually moves the stage 1, the light source 2 and the micro filter under test 7 through the two-dimensional displacement stage 6. The detector 43 and the lens 44 acquire spectral image information of the micro filter under test 7 at different positions under different quasi-monochromatic light and send it to the industrial control computer 5.

[0067] In this embodiment, the two-dimensional displacement stage 6 moves 12mm per step along the Y-axis and 25mm per step along the X-axis.

[0068] Step 3: The industrial control computer 5 obtains the spectral performance of the micro-filter 7 under test based on the spectral image information.

[0069] Step 4: Fix the rotatable biasing device 3 to the second mounting through hole 131 in the middle of the second carrier plate 13.

[0070] Step 5: The industrial control computer 5 controls the rotatable polarizer 3 to rotate to different polarization angles and controls the light source 2 to switch to quasi-monochromatic light of different wavelengths. The two-dimensional displacement stage 6 gradually moves the stage 1, the light source 2, the rotatable polarizer 3 and the micro filter under test 7. The detector 43 and the lens 44 acquire polarization image information of the micro filter under test 7 at different polarization angles, different quasi-monochromatic lights and different positions and send it to the industrial control computer 5.

[0071] Step 6: The industrial control computer 5 obtains the polarization performance of the micro-filter 7 under test based on the polarization image information, and completes the detection of the spectral performance and polarization performance of the micro-filter.

[0072] The detection device and method provided in this embodiment can also be used for focal plane arrays, which can consist of two or more, or even three or more, filter channels. This embodiment also uses the aforementioned detection device and method to detect a focal plane array, which is divided into multiple bandpass filtering regions in the spectral direction, including one wide-bandpass channel P and four narrow-bandpass channels B1 to B4, totaling five spectral channels covering a wavelength range of approximately 0.45 μm to 0.90 μm. Channel P is a wide-bandpass filtering region covering the visible to near-infrared range; channels B1 to B4 are narrow-bandpass filtering regions distributed in the blue, green, red, and near-infrared bands. Each channel achieves selective transmission of specific wavelengths through the bandpass filter film, thereby realizing the acquisition and decomposition imaging of multispectral information. The focal plane filter array also includes four polarization filter regions, corresponding to four linear polarization directions: P1: 0°; P2: 45°; P3: 90°; P4: 135°. The polarization direction error of each polarization filter region is preferably less than 0.1°, and the extinction ratio is better than 1:1000, which is used to achieve high-precision polarization information measurement.

[0073] In this embodiment, by moving a single lens up and down, in conjunction with a tunable monochromatic illumination light source and a rotatable polarizer, the spectral and polarization performance of a microfilter can be measured within the same detection optical path. No separate beam-splitting path or complex motion mechanism is required during the measurement process, enabling integrated measurement of parameters such as the spectral transmittance characteristics, polarization direction deviation, and extinction ratio of the microfilter.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A device for detecting the spectral and polarization performance of a microfilter, wherein the microfilter has a size ranging from 0.1 mm to 10 mm; characterized in that: Includes a stage (1), a light source (2) and a rotatable polarizer (3) installed inside the stage (1), a detection unit (4) installed above the stage (1), and an industrial control computer (5) electrically connected to the light source (2), the rotatable polarizer (3) and the detection unit (4) respectively. The stage (1) includes a cylindrical frame (11), a first plate (12) mounted on the top of the frame (11), and a second plate (13) mounted in the middle of the frame (11). The first plate (12) has a first mounting through hole (121) in the middle for mounting the micro filter (7) to be tested. The second plate (13) is parallel to the first plate (12), and has a second mounting through hole (131) in the middle that corresponds to the first mounting through hole (121). The rotatable polarizer (3) is detachably mounted in the second mounting through hole (131). The light source (2) is located below the second plate (13) and corresponds to the second mounting through hole (131). The active end of the detection unit (4) corresponds to the first mounting through hole (121) and is used to collect image data of the micro filter (7) under test and send it to the industrial control computer. The industrial control computer (5) is electrically connected to the light source (2), the rotatable polarizer (3) and the detection unit (4), and is used to control the light source (2), the rotatable polarizer (3) and the detection unit (4), and to process and analyze the image data collected by the detection unit (4) to obtain the spectral performance and polarization performance of the micro filter (7) under test.

2. The device for detecting the spectral and polarization performance of microfilters according to claim 1, characterized in that: It also includes a two-dimensional displacement stage (6); The two-dimensional displacement stage (6) is located at the bottom of the loading frame (11) and is electrically connected to the industrial control computer (5) for moving the loading stage (1) under the control of the industrial control computer (5).

3. The device for detecting the spectral and polarization performance of microfilters according to claim 1 or 2, characterized in that: The detection unit (4) includes a bracket (41) installed on one side of the load frame (11), an axial displacement stage (42) installed on the bracket (41), a detector (43) set at the working end of the axial displacement stage (42), and a lens (44) installed at the working end of the detector (43). The axial displacement stage (42) and detector (43) are both electrically connected to the industrial control computer (5); The axial displacement stage (42) is used to drive the detector (43) to move up and down; The lens (44) is oriented toward the first mounting through hole (121).

4. The device for detecting the spectral and polarization performance of microfilters according to claim 3, characterized in that: The first mounting through hole (121) is a stepped through hole with its stepped surface facing upwards. The stepped surface is used to support the micro filter (7) to be tested.

5. The device for detecting the spectral and polarization performance of microfilters according to claim 4, characterized in that: The light source (2) is a broadband adjustable light source with a spectral range of 400nm~2000nm.

6. The device for detecting the spectral and polarization performance of microfilters according to claim 5, characterized in that: The detector (43) is a CMOS detector with a pixel size of 4.5μm×4.5μm and a pixel count of 5120×5120.

7. A method for detecting the spectral and polarization performance of a microfilter, employing the detection device for the spectral and polarization performance of a microfilter as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Remove the rotatable polarizer (3) from the second plate (13) inside the stage (1), and place the micro filter (7) to be tested at the first mounting through hole (121) in the middle of the first plate (12); Step 2: The industrial control computer (5) controls the light source (2) to switch to quasi-monochromatic light of different wavelengths, and gradually moves the stage (1), the light source (2) and the micro filter (7) under test. The detection unit (4) acquires the spectral image information of the micro filter (7) under different quasi-monochromatic light and at different positions and sends it to the industrial control computer (5). Step 3: The industrial computer (5) acquires the spectral performance of the micro-filter (7) under test based on the spectral image information; Step 4: Fix the rotatable deflector (3) to the second mounting through hole (131) in the middle of the second carrier plate (13); Step 5: The industrial computer (5) controls the rotatable polarizer (3) to rotate to different polarization angles and controls the light source (2) to switch to quasi-monochromatic light of different wavelengths. The stage (1), light source (2), rotatable polarizer (3) and micro filter (7) under test are moved step by step. The detection unit (4) acquires the polarization image information of the micro filter (7) under test at different polarization angles, different quasi-monochromatic lights and different positions and sends it to the industrial computer (5). Step 6: The industrial control computer (5) obtains the polarization performance of the micro-filter (7) under test based on the polarization image information, and completes the detection of the spectral performance and polarization performance of the micro-filter.

8. The method for detecting the spectral and polarization performance of a microfilter according to claim 7, characterized in that: Step 1 specifically involves removing the rotatable polarizer (3) from the second carrier plate (13) inside the stage (1), placing the micro filter (7) to be tested at the first mounting through hole (121) in the middle of the first carrier plate (12), setting the two-dimensional displacement stage (6) to zero, and adjusting the positions of the detector (43) and lens (44) through the axial displacement stage (42) so that the object-side focus of the lens (44) is aligned with the upper surface of the micro filter (7) to be tested.

9. The method for detecting the spectral and polarization performance of a microfilter according to claim 8, characterized in that: Step 2 is as follows: the industrial control computer (5) controls the light source (2) to switch to quasi-monochromatic light of different bands, and moves the stage (1), light source (2) and micro filter (7) under test step by step through the two-dimensional displacement stage (6). The detector (43) and lens (44) acquire spectral image information of the micro filter (7) under test at different positions under different quasi-monochromatic light and send it to the industrial control computer (5).

10. The method for detecting the spectral and polarization performance of a microfilter according to claim 9, characterized in that: Step 5 is as follows: the industrial control computer (5) controls the rotatable polarizer (3) to rotate to different polarization angles and controls the light source (2) to switch to quasi-monochromatic light of different bands. The stage (1), light source (2), rotatable polarizer (3) and micro filter (7) under test are moved step by step through the two-dimensional displacement stage (6). The polarization image information of the micro filter (7) under test at different polarization angles, different quasi-monochromatic light and different positions is obtained through the detector (43) and lens (44) and sent to the industrial control computer (5).

Images