A method of aligning a dispersive imaging spectrometer

Abstract

The application discloses a kind of dispersion type imaging spectrometer's method of adjustment, the method utilizes the adjustment device of imaging spectrometer to carry out whole machine adjustment to dispersion type imaging spectrometer, the device includes light source, integrating sphere, inner focusing collimator and reading microscope, wherein the light source uses monochromatic light source, mercury lamp or complex light source;The inner focusing collimator uses transmission type, total reflection type or catadioptric structure, is composed of target, collimating objective and inner focusing mechanism;The method can be adjusted to imaging spectrometer for slit installation on spectrometer.The above-mentioned method does not need to design and process redundant auxiliary adjustment component, all use the component of instrument itself to carry out adjustment and fix during adjustment process, low in cost, few adjustment steps, fast, high precision, it is favorable to the adjustment of batch production imaging spectrometer.

Description

[0001] This application is a divisional application filed in respect of the granted patent (patent number 202011255094.9). Technical Field

[0002] This invention relates to the field of imaging spectrometer technology, and in particular to a method for assembling and adjusting a dispersive imaging spectrometer. Background Technology

[0003] Imaging spectrometers acquire two-dimensional geometric and spectral information of a target and are widely used in remote sensing and scientific research. They typically consist of a telescope objective and a spectrometer, with dispersive elements including gratings, prisms, or prism-grating assemblies. The assembly and adjustment methods for imaging spectrometers vary depending on the instrument design and the assembler. Some slits are mounted on the front-view telescope system, while others are mounted on the spectrometer's object plane. A common method involves mounting the slit on the front-view telescope's image plane using a collimator, then installing auxiliary assembly components on the spectrometer's object plane, mounting the detector on the spectrometer's image plane, illuminating the auxiliary assembly components with a mercury lamp, adjusting the relative positions of the detector and spectrometer, and finally illuminating the polychromatic point light source with a collimator before mounting the front-view telescope onto the spectrometer, completing the assembly and adjustment of the entire instrument.

[0004] The main problem with the existing technology is that different auxiliary assembly and adjustment components need to be designed and manufactured for dispersive imaging spectrometers with different parameters. The auxiliary assembly and adjustment components have low versatility and high cost. The auxiliary assembly and adjustment components are different from the components of the instrument itself. When the auxiliary assembly and adjustment components are removed and the components of the instrument itself are reinstalled, the reinstallation may affect the accuracy of the instrument itself. The overall assembly and adjustment accuracy needs to be improved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for assembling and adjusting a dispersive imaging spectrometer. This method does not require the design and fabrication of additional auxiliary assembly and adjustment components. During the assembly and adjustment process, all components of the instrument itself are used for assembly and adjustment. This method is low in cost, has fewer assembly and adjustment steps, is fast, and has high precision, which is beneficial for the assembly and adjustment of mass-produced imaging spectrometers.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for assembling and adjusting a dispersive imaging spectrometer, wherein the method utilizes an assembly and adjustment device for the dispersive imaging spectrometer to perform overall assembly and adjustment of the spectrometer, the device comprising a light source, an integrating sphere, an internal focusing collimator, and a reading microscope, wherein:

[0008] The light source is a monochromatic light source, a mercury lamp, or a polychromatic light source;

[0009] The internal focusing collimator adopts a transmission, total reflection, or catadioptric structure and consists of a target, a collimating objective lens, and an internal focusing mechanism.

[0010] For an imaging spectrometer with a slit mounted on the spectrometer, the assembly and adjustment method is as follows:

[0011] The detector is installed at the rear end of the imaging spectrometer, and the front telescope is installed at the front end. A star plate is selected as the target for the internal focusing collimator. First, the target is adjusted to be at its focal plane. The light source is turned on, illuminating the star plate target after passing through the integrating sphere. Parallel light is then output after passing through the collimating lens of the internal focusing collimator. The image formed by the star plate is converged by the front telescope and imaged onto the focal plane, then imaged onto the detector by the spectrometer. The position of the target is adjusted, and the size of the star plate spot on the detector is observed. When the spot size is smallest, sharpest, and brightest, the value is recorded. The defocus distance of the internal focusing collimator is described; based on the relationship between the focal length of the internal focusing collimator and the focal length of the imaging spectrometer, the trimming amount of the detector trimming pad is calculated, and the trimming pad is trimmed until the target is located at the focal plane of the internal focusing collimator, and the star image seen on the detector is the brightest and sharpest, at which point the trimming pad is stopped; then the light source is replaced with a polychromatic light source, and the relative angle between the detector and the spectrometer is adjusted so that the point field polychromatic image of the light source is sharp and aligned with the detector column. At this point, the detector is fixed to achieve the adjustment of the imaging spectrometer detector.

[0012] The front telescope is removed, and the slit is installed at the front end of the imaging spectrometer. The light source is replaced with a monochromatic light source. The monochromatic light source is uniformly irradiated onto the slit after passing through the integrating sphere, and then imaged onto the detector after passing through the spectrometer. By adjusting the front-to-back distance between the slit and the front end of the spectrometer, the edges of the monochromatic image of the slit are made sharp. Then the slit is rotated to make the monochromatic image of the slit on the detector sharp and aligned with the detector row. At this point, the slit is fixed to achieve fine adjustment of the slit.

[0013] The front telescope is installed at the front of the spectrometer. The target is replaced with a striped plate, and the light source is replaced with polychromatic light. First, the target is adjusted to be at its focal plane. The light source is turned on and illuminates the target after passing through the integrating sphere. Parallel light is output after passing through the collimating lens of the internal focusing collimator. The image formed by the target is converged by the front telescope and imaged on the focal plane. Then, it is imaged on the detector after passing through the slit and the spectrometer. The position of the target is adjusted, and the fringe contrast of the striped plate image is observed. When the fringe is sharpest, the defocus distance of the internal focusing collimator is recorded. Based on the relationship between the focal length of the internal focusing collimator and the focal length of the imaging spectrometer, the trimming amount of the front telescope trimming pad is calculated and trimmed until the target is located at the focal plane of the internal focusing collimator. Then, the trimming of the trimming pad is stopped, and the front telescope is fixed to achieve fine adjustment of the front telescope.

[0014] After adjusting the imaging spectrometer detector, finely adjusting the slit, and finely adjusting the front telescope using the aforementioned device, the entire imaging spectrometer can be assembled and adjusted.

[0015] As can be seen from the technical solution provided by the present invention, the above method does not require the design and processing of extra auxiliary assembly and adjustment components. During the assembly and adjustment process, all components of the instrument itself are used for assembly and adjustment and fixation. This method is low in cost, has fewer assembly and adjustment steps, is fast, and has high precision, which is beneficial for the assembly and adjustment of mass-produced imaging spectrometers. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the assembly and adjustment device for a dispersive imaging spectrometer provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram illustrating the detector adjustment process when the slit is mounted on the spectrometer according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the slit fine adjustment process when the slit is installed on the spectrometer according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram illustrating the fine adjustment process of the front telescope when the slit is mounted on the spectrometer, as described in an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the optical path during the assembly and adjustment process of the example provided in this invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 protection scope of the present invention.

[0023] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings, such as... Figure 1 The diagram shows a schematic of the assembly and adjustment device for a dispersive imaging spectrometer provided in an embodiment of the present invention. The device 1 mainly includes a light source 2, an integrating sphere 3, and an internal focusing collimator 4, wherein:

[0024] The light source 2 is a monochromatic light source, a mercury lamp, or a polychromatic light source;

[0025] The internal focusing collimator 4 adopts a transmission, total reflection, or catadioptric structure, and consists of a target 5, a collimating objective lens 7, and an internal focusing mechanism 6, wherein:

[0026] The target 5 includes a star-shaped plate and a striped plate. A series of star-shaped plates and striped plates can be manufactured at once. The size of the star-shaped holes and the line width of the striped plates are selected according to the focal length of the internal focusing collimator 4, the focal length of the front mirror, and the size of the detector pixels.

[0027] In common imaging spectrometers, some slits are mounted on the focal plane of the front telescope system, while others are mounted on the object plane of the spectrometer. For imaging spectrometers with slits mounted on the spectrometer, the specific assembly and adjustment process using the aforementioned device is as follows:

[0028] like Figure 2 The diagram illustrates the detector adjustment process when the slit is mounted on the spectrometer according to an embodiment of the present invention. The detector is mounted at the rear end of the imaging spectrometer, and the front telescope is mounted at the front end. The target 5 of the internal focusing collimator 4 is a star plate. First, the target 5 is adjusted to be located at its focal plane. The light source 2 is turned on, and the star plate target 5 is illuminated after passing through the integrating sphere 3. Then, parallel light is output after passing through the collimating lens 7 of the internal focusing collimator 4. The image formed by the star plate is converged by the front telescope and imaged on the focal plane, and then imaged on the detector by the spectrometer. The position of the target 5 is adjusted, and the size of the light spot of the star plate on the detector is observed. When the light spot is at its smallest, sharpest, and brightest, record the defocus distance of the inner focusing collimator 4; based on the relationship between the focal length of the inner focusing collimator 4 and the focal length of the imaging spectrometer, calculate the trimming amount of the detector trimming pad, and trim the trimming pad until the target 5 is located at the focal plane of the inner focusing collimator 4, and the star image seen on the detector is the brightest and sharpest, then stop trimming the trimming pad; then replace the light source 2 with a polychromatic light source, adjust the relative angle between the detector and the spectrometer inside the imaging spectrometer, so that the point field polychromatic image of the light source 2 is sharp and aligned with the detector column, then fix the detector to achieve adjustment of the imaging spectrometer detector.

[0029] like Figure 3The diagram illustrates the fine adjustment process of the slit when it is mounted on the spectrometer according to an embodiment of the present invention. The front telescope is removed, and the slit is mounted on the front end of the imaging spectrometer. The light source 2 is replaced with a monochromatic light source. The monochromatic light source 2 is uniformly irradiated onto the slit after passing through the integrating sphere 3, and then imaged onto the detector after passing through the spectrometer. By adjusting the front-to-back distance between the slit and the front end of the spectrometer, the edge of the monochromatic image of the slit is made sharp. Then, the slit is rotated to make the monochromatic image of the slit on the detector sharp and aligned with the detector row. At this point, the slit is fixed to achieve fine adjustment of the slit.

[0030] like Figure 4 The diagram illustrates the fine-tuning process of the front telescope when the slit is mounted on the spectrometer according to an embodiment of the present invention. The front telescope is mounted at the front of the spectrometer. The target 5 is replaced with a stripe plate, and the light source 2 is replaced with polychromatic light. First, the target 5 is adjusted to be at its focal plane. The light source 2 is turned on, illuminating the target 5 after passing through the integrating sphere 3. Parallel light is then output after passing through the collimating lens 7 of the internal focusing collimator 4. The image formed by the target 5 is converged by the front telescope and imaged onto the focal plane, then imaged onto the detector after passing through the slit and the spectrometer. Adjust the position of the target 5, observe the fringe contrast of the fringe image, and record the defocus distance of the inner focusing collimator 4 when the fringe is sharpest. Calculate the trimming amount of the front telescope trimming pad based on the relationship between the focal length of the inner focusing collimator 4 and the focal length of the imaging spectrometer, and trim until the target 5 is located at the focal plane of the inner focusing collimator 4, and the fringe image observed on the detector is the brightest and sharpest. Then stop trimming the trimming pad and fix the front telescope to achieve fine adjustment of the front telescope.

[0031] After adjusting the imaging spectrometer detector, finely adjusting the slit, and finely adjusting the front telescope using the aforementioned device, the entire imaging spectrometer can be assembled and adjusted.

[0032] In a specific implementation, the imaging spectrometer is a dispersion system based on an area array detector; the internal focusing collimator 4 can be implemented by modifying a collimator commonly used in laboratories.

[0033] The following is a detailed explanation of the assembly and adjustment process of the above-mentioned device using a specific example. In this example, a visible and near-infrared imaging spectrometer with a slit mounted on a spectrometer is assembled and adjusted. The detector used has a size of 2048 yuan × 2048 yuan and a pixel size of 11 μm × 11 μm. Its technical specifications are shown in Table 1.

[0034] Table 1 System Indicator Requirements

[0035] System Indicators Indicator Requirements System F number 2.4 Spectral range 0.4~1.0μm Front camera focal length 100mm Spectrometer magnification -1 Slit length 22mm Slit width 30um Dispersion width 11.264mm

[0036] Based on the specifications of the imaging spectrometer to be assembled and adjusted, the assembly and adjustment process using the aforementioned device is as follows:

[0037] 1. The internal focusing collimator has a focal length f1 of 600mm and an adjustable focal plane range of ±50mm. Based on the focal length of the internal focusing collimator, the focal length of the front mirror, and the pixel size and width of the detector, a dot plate with a diameter less than (11um × 600mm) / 100mm = 66um and a stripe plate with a stripe spacing greater than 66um are selected. In this embodiment, a dot plate with a diameter of 50um and a stripe plate with a stripe spacing of 100um are used for assembly and adjustment.

[0038] 2. For example Figure 5 The diagram shows the optical path of the assembly and adjustment process in the example of this invention. First, initial adjustment of the detector is performed. The detector is installed at the rear end of the spectrometer, and the front telescope is installed at the front end of the spectrometer. A star plate is selected as the target for the internal focusing collimator. The target of the internal focusing collimator is adjusted to its focal plane. A 632.8nm laser source is turned on, illuminating the star target of the internal focusing collimator after passing through the integrating sphere. Parallel light is output through the collimating lens of the internal focusing collimator. The image formed by the star plate is converged by the front telescope and imaged onto the focal plane of the front telescope system. The image of the star plate is then imaged onto the detector by the spectrometer. The position of the internal focusing collimator target is adjusted, and the spot size of the star plate on the imaging spectrometer is observed. When the spot is sharpest, brightest, and smallest, the defocus distance d of the internal focusing collimator is recorded as -18mm. Based on the relationship between the focal length f1 of the internal focusing collimator and the focal length f2 of the imaging spectrometer, the trimming amount of the detector trimming pad is calculated. The trimming pad is trimmed until the star plate of the inner focusing collimator is located at the focal plane of the inner focusing collimator. At this point, the star plate image seen on the detector is the brightest and sharpest. At this point, the trimming pad trimming is stopped, and the initial adjustment of the detector is achieved.

[0039] 3. Replace the light source with a polychromatic tungsten lamp, adjust the relative angle between the detector and the spectrometer to make the polychromatic image of the light source in the point field of view sharp and aligned with the detector array, fix the detector, and achieve fine adjustment of the detector.

[0040] 4. Remove the front telescope and install the slit at the front end of the spectral imaging system. Replace the light source with a monochromatic 632.8nm laser. The monochromatic light source illuminates the slit uniformly after passing through the integrating sphere. The slit is then imaged onto the detector after passing through the spectrometer. By adjusting the front-to-back distance Δx between the slit and the front face of the spectrometer, the edges of the monochromatic image of the slit are made sharp. Then, rotate the slit to make the monochromatic image of the slit on the detector sharp and aligned with the detector line. Fix the slit to achieve fine adjustment of the slit.

[0041] 5. Install the front telescope at the front of the spectrometer, replace the target with a striped plate, and replace the light source with a polychromatic tungsten lamp. First, adjust the target of the internal focusing collimator to its focal plane. Turn on the polychromatic light source 2, which illuminates the striped plate target 5 after passing through the integrating sphere 3. The light then passes through the collimating lens 7 and outputs parallel light. The image formed by the striped plate is converged by the front telescope of the imaging spectrometer and imaged onto the focal plane of the front telescope system. After passing through the slit and the spectrometer, the image is imaged onto the detector. Adjust the position of the target 5 and observe the fringe contrast of the striped plate image in the imaging spectrometer. When the fringes are sharpest, record the defocus distance d of the internal focusing collimator 5 as -3mm. Based on the relationship between the focal length of the internal focusing collimator and the focal length of the imaging spectrometer... Calculate the trimming amount of the front mirror trimming pad and trim it until the stripe plate is located at the focal plane of the inner focusing collimator, and the image of the stripe plate seen on the detector is the brightest and sharpest. Then stop trimming the trimming pad and fix the front telescope to achieve fine adjustment of the front telescope.

[0042] After the above adjustments, the entire assembly and adjustment of the imaging spectrometer can be completed.

[0043] It is worth noting that the contents not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

[0044] In summary, the assembly and adjustment method of the present invention does not require the design and processing of additional auxiliary assembly and adjustment components, such as the commonly used auxiliary aperture process slit. During the assembly and adjustment process, all components of the instrument itself are used for assembly and adjustment and fixation. There is no need to remove the auxiliary assembly and adjustment components and then reinstall the components of the instrument itself. It has low cost, fewer assembly and adjustment steps, fast speed and high precision, which is beneficial for the assembly and adjustment of mass-produced imaging spectrometers.

[0045] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included 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 method of aligning a dispersive imaging spectrometer, comprising: The method utilizes an imaging spectrometer adjustment device to adjust the whole imaging spectrometer, the imaging spectrometer adjustment device comprises a light source, an integrating sphere, an internal focusing collimator and a reading microscope, wherein: The light source adopts a monochromatic light source, a mercury lamp or a complex light source; The internal focusing collimator adopts a transmission type, a total reflection type or a catadioptric type structure, and is composed of a target, a collimating objective and an internal focusing mechanism; For the imaging spectrometer with a slit installed on the spectrometer, the adjustment method is specifically as follows: The detector is installed at the rear end of the imaging spectrometer, the front telescope is installed at the front end of the imaging spectrometer, the target of the internal focusing collimator is a star point plate, first, the target is adjusted to be located at the focal plane, the light source is turned on to illuminate the target through the integrating sphere, and then parallel light is output through the collimating mirror of the internal focusing collimator; the image formed by the star point plate is converged by the front telescope and then imaged on the focal plane, and then imaged on the detector through the spectrometer; the position of the target is adjusted, the size of the light spot of the star point plate on the detector is observed, when the light spot is the smallest, the sharpest and the brightest, the defocusing distance of the internal focusing collimator is recorded; according to the relationship between the focal length of the internal focusing collimator and the focal length of the imaging spectrometer, the cutting amount of the cutting pad of the detector is calculated, and the cutting pad is cut until the target is located at the focal plane of the internal focusing collimator, the star point plate image on the detector is the brightest and the sharpest, and the cutting of the cutting pad is stopped; then the light source is replaced by a complex light source, the relative angle between the detector and the spectrometer is adjusted, the point field complex image of the light source is sharp and aligned with the detector column, at this time the detector is fixed, and the adjustment of the detector of the imaging spectrometer is realized; The front telescope is removed, the slit is installed at the front end of the imaging spectrometer, and the light source is replaced by a monochromatic light source; the monochromatic light source is uniformly irradiated to the slit through the integrating sphere, and then imaged on the detector through the spectrometer; the front and rear distance between the slit and the front end surface of the spectrometer is adjusted, so that the edge of the slit monochromatic image is sharp, then the slit is rotated, so that the slit monochromatic image on the detector is sharp and aligned with the detector row, at this time the slit is fixed, and the fine adjustment of the slit is realized; The front telescope is installed at the front end of the spectrometer, the target is replaced by a stripe plate, and the light source is replaced by a complex light; first, the target is adjusted to be located at the focal plane, the light source is turned on to illuminate the target through the integrating sphere, and then parallel light is output through the collimating mirror of the internal focusing collimator; the image formed by the target is converged by the front telescope and then imaged on the focal plane, and then imaged on the detector through the slit and the spectrometer; the position of the target is adjusted, the stripe contrast of the stripe plate image is observed, when the stripe is the sharpest, the defocusing distance of the internal focusing collimator is recorded; according to the relationship between the focal length of the internal focusing collimator and the focal length of the imaging spectrometer, the cutting amount of the cutting pad of the front telescope is calculated, and the cutting pad is cut until the target is located at the focal plane of the internal focusing collimator, the cutting of the cutting pad is stopped, and the front telescope is fixed, and the fine adjustment of the front telescope is realized. After the adjustment of the imaging spectrometer detector, the fine adjustment of the slit and the fine adjustment of the pre-telescope by the adjustment device of the imaging spectrometer are realized, and the whole machine adjustment of the imaging spectrometer is realized.

2. The adjustment method of the dispersive imaging spectrometer according to claim 1, characterized in that, The size of the star point hole of the star point plate and the line width of the stripe plate are selected according to the focal length of the inner focusing collimator, the focal length of the pre-telescope and the size of the detector pixel.

3. The adjustment method of the dispersive imaging spectrometer according to claim 1, characterized in that, The imaging spectrometer is a dispersive system based on a surface array detector; The inner focusing collimator is realized by modifying a commonly used collimator in the laboratory.

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