Low-temperature infrared material refractive index measuring device and measuring method based on single-point detection

Abstract

The invention discloses a low-temperature infrared material refractive index measuring device and a measuring method based on single-point detection, which relates to the field of optical measurement technology. The key points of the technical solution are: including: an infrared light source component, which outputs infrared light; a rotating table, which is placed in a vacuum thermostat and adjusts the rotation angle of a test prism; a spectroscope, in which the infrared light is transmitted to the test prism after passing through the spectroscope, and the spectroscope reflects and outputs the light that returns along the original path after being reflected by a reflective film on the back of the test prism; an aiming device, which obtains the signal amplitude that changes with the rotation angle of the test prism through a single-point detector; a processor, which is used to calculate the deflection angle of the test prism after adjusting the rotation angle by a weighted average method according to the signal amplitude and the rotation angle of the rotating table, and determine the refractive index at the current temperature according to the deflection angle. The invention does not require a self-collimating light tube for comparison processing, the optical path of the measurement process is relatively simple, the measurement accuracy and effect are high, and the application cost is low.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement technology, and more specifically, to a low-temperature infrared material refractive index measuring device and a measuring method based on single-point detection. Background Art

[0002] Due to the widespread application of infrared technology, the superiority of infrared optical system aiming system has been discovered by researchers from various countries and is suitable for the research on the reliability of infrared materials in low-temperature vacuum environment of aerospace infrared materials.

[0003] The existing refractive index measuring instrument is mainly composed of a second-level autocollimating light tube, a precision turntable, a temperature control system, a parallel light tube, an aiming system and a light source component. When the test conditions change, the angle of the test prism is rotated to keep the center of mass position of the front and rear in the aiming system consistent. Finally, the rotation angle of the test prism is measured by the autocollimating light tube, and the refractive index change of the test prism is obtained through relevant calculations. The entire test process requires a large number of instruments and equipment, a complex optical path, and a high application cost, which in turn affects the measurement accuracy. In addition, the aiming system generally uses an array detector to detect the center of mass position, which is inefficient during continuous measurement and has a high application cost of the array detector.

[0004] Therefore, how to research and design a low-temperature infrared material refractive index measurement device and measurement method based on single-point detection that can overcome the above-mentioned defects is a problem that we urgently need to solve. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a low-temperature infrared material refractive index measuring device and method based on single-point detection. The entire measurement process does not require a self-collimating light tube for comparison processing, the optical path of the measurement process is relatively simple, the measurement accuracy and effect are high, and the application cost is low.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] In a first aspect, a low-temperature infrared material refractive index measuring device based on single-point detection is provided, comprising:

[0008] An infrared light source assembly, used for outputting infrared light of a preset wavelength;

[0009] A rotating stage is placed in the vacuum incubator and synchronously adjusts the rotation angle of the test prism during rotation;

[0010] A beam splitter, wherein the infrared light passes through the beam splitter and is transmitted to the test prism, and the beam splitter reflects and outputs the light that returns along the original path after being reflected by the reflective film on the back of the test prism;

[0011] The aiming device acquires the signal amplitude representing the center coordinate of the light spot which changes with the rotation angle of the test prism through a single-point detector;

[0012] The processor is used to calculate the deflection angle of the test prism after adjusting the rotation angle according to the signal amplitude and the rotation angle of the rotating table by a weighted average method, and determine the refractive index at the current temperature according to the deflection angle.

[0013] Further, the infrared light source assembly includes an infrared monochromator, a high temperature cavity black body, a chopper disk, an off-axis mirror and a plane mirror;

[0014] The divergent monochromatic light emitted from the infrared monochromator exit slit is converted into collimated parallel light by an off-axis mirror, and then reflected by a plane mirror into the test prism.

[0015] Furthermore, the wavelength range of the infrared light is 2um to 14um.

[0016] Furthermore, the beam splitter is a semi-transparent and semi-reflective mirror.

[0017] Further, the aiming device is equipped with a preamplifier and a lock-in amplifier;

[0018] When the infrared light is focused on the center of the photosensitive surface of the single-point detector, it is amplified by a preamplifier and output after being processed by a phase-locked amplifier to determine the signal amplitude that represents the maximum position of the light beam output signal.

[0019] In a second aspect, a method for measuring the refractive index of a low-temperature infrared material based on single-point detection is provided, comprising the following steps:

[0020] S1: Output infrared light of a preset wavelength through an infrared light source component;

[0021] S2: placing the rotating stage in a vacuum incubator and synchronously adjusting the rotation angle of the test prism during the rotation;

[0022] S3: The infrared light passes through the beam splitter and is transmitted to the test prism, and the beam splitter reflects and outputs the light that returns along the original path after being reflected by the reflective film on the back of the test prism;

[0023] S4: obtaining, through a single-point detector, a signal amplitude representing the coordinates of the center of the light spot that changes with the rotation angle of the test prism;

[0024] S5: According to the signal amplitude and the rotation angle of the rotating stage, the deflection angle of the test prism after the rotation angle is adjusted is calculated by a weighted average method, and the refractive index at the current temperature is determined according to the deflection angle.

[0025] Furthermore, the calculation formula of the deflection angle is specifically:

[0026]

[0027] Where R represents the signal amplitude representing the center coordinate of the light spot; T represents the measurement period; R i Indicates the amplitude information obtained at the i-th sampling time; u i Represents the rotation angle of the rotation stage obtained at the i-th sampling time.

[0028] Furthermore, the calculation formula of the deflection angle is specifically:

[0029]

[0030] Where R represents the signal amplitude representing the center coordinate of the light spot; T represents the measurement period; R i Indicates the amplitude information obtained at the i-th sampling time; u i represents the rotation angle of the rotating table obtained at the i-th sampling time; K represents the calibration coefficient, which is determined by the measuring instrument.

[0031] Furthermore, the process of obtaining the amplitude information is specifically as follows:

[0032] Obtain continuous amplitude information within a single sampling period;

[0033] Sort the continuous amplitude information;

[0034] Filter the amplitude information of the preset percentage of the sorted columns and the sorted columns;

[0035] Calculate the mean of the remaining amplitude information to obtain the final amplitude information.

[0036] Furthermore, the preset percentage is 20%-25%.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The low-temperature infrared material refractive index measuring device based on single-point detection proposed by the present invention adopts the signal amplitude that continuously characterizes the center coordinates of the light spot through the single-point detector, and combines the rotation angle of the rotating table to perform enhanced average calculation. The entire measurement process does not require the self-collimation light tube for comparison processing. The optical path of the measurement process is relatively simple, the measurement accuracy and effect are high, and the application cost is low.

[0039] 2. The low-temperature infrared material refractive index measurement method based on single-point detection proposed in the present invention uses a single-point detector and related algorithms to achieve continuous measurement of the deflection angle of the test prism, which has lower application cost than the traditional application array detector;

[0040] 3. The present invention can effectively reduce the error impact caused by instruments and equipment by sorting and filtering the continuous amplitude information within the sampling period and taking the average as the final amplitude information, making the entire measurement result more stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0042] Figure 1 is a working principle diagram in an embodiment of the present invention;

[0043] Figure 2 is a flow chart in an embodiment of the present invention;

[0044] Figure 3 It is a schematic diagram of measurement results in an embodiment of the present invention.

[0045] Marks and corresponding parts names in the attached drawings:

[0046] 101. Infrared monochromator; 102. High-temperature cavity blackbody; 103. Off-axis mirror; 104. Plane mirror; 105. Spectrometer; 106. Vacuum thermostat; 107. Rotating table; 108. Aiming device. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0048] Embodiment 1: A low-temperature infrared material refractive index measuring device based on single-point detection, such as Figure 1 As shown, it includes an infrared light source assembly, a rotating stage 107, a spectroscope 105, a aiming device 108 and a processor.

[0049] Among them, the infrared light source assembly is used to output infrared light with a wavelength range of 2um-14um. The rotating table 107 is placed in the vacuum thermostat 106, and the rotation angle of the test prism is synchronously adjusted during rotation. The spectrometer 105 is a semi-transparent and semi-reflective mirror. The infrared light passes through the spectrometer 105 and is transmitted to the test prism, and the spectrometer 105 reflects and outputs the light that returns to the original path after being reflected by the reflective film on the back of the test prism. The aiming device 108 obtains the signal amplitude that characterizes the center coordinates of the light spot that changes with the rotation angle of the test prism through a single-point detector. The processor is used to calculate the deflection angle of the test prism after adjusting the rotation angle by a weighted average method based on the signal amplitude and the rotation angle of the rotating table 107, and determine the refractive index at the current temperature according to the deflection angle.

[0050] The infrared light source assembly includes an infrared monochromator 101, a high temperature cavity black body 102, a chopper disk, an off-axis mirror 103 and a plane mirror 104; the divergent monochromatic light emitted from the outlet slit of the infrared monochromator 101 is converted into collimated parallel light by the off-axis mirror 103, and then reflected by the plane mirror 104 into the test prism.

[0051] The aiming device 108 is equipped with a preamplifier and a phase-locked amplifier; when the infrared light is focused to the center of the photosensitive surface of the single-point detector, it is amplified by the preamplifier and output after being processed by the phase-locked amplifier to determine the signal amplitude representing the maximum position of the light beam output signal.

[0052] Example 2: A method for measuring the refractive index of low-temperature infrared materials based on single-point detection, such as Figure 2 As shown, the following steps are included:

[0053] S1: Output infrared light of a preset wavelength through an infrared light source component;

[0054] S2: placing the rotating stage 107 in the vacuum thermostat 106, and synchronously adjusting the rotation angle of the test prism during the rotation;

[0055] S3: The infrared light passes through the beam splitter 105 and is transmitted to the test prism, and the beam splitter 105 reflects and outputs the light that is reflected by the reflective film on the back of the test prism and returns along the original path;

[0056] S4: obtaining, through a single-point detector, a signal amplitude representing the coordinates of the center of the light spot that changes with the rotation angle of the test prism;

[0057] S5: According to the signal amplitude and the rotation angle of the rotating stage 107, the deflection angle of the test prism after adjusting the rotation angle is calculated by a weighted average method, and the refractive index at the current temperature is determined according to the deflection angle.

[0058] Specifically, the test calculation of single-point centroid detection is a power weighted method. The signal amplitude is used as a weighting coefficient for weighted summation, and the weighted average of the angle offset is calculated to obtain the angle value corresponding to the center position of the amplitude, which can be compared to the process of finding the center of mass of an object. This is used to represent the offset corresponding to the peak value in the aiming state, and the waveform diagram of the collected signal amplitude and the angle value (also the rotation angle of the rotating table 107) is regarded as a pointer. The signal amplitude is represented by its ordinate, and its corresponding angle value is represented by the abscissa. Then the amplitudes received by the phase-locked amplifiers of these points are multiplied by the corresponding angle value and summed.

[0059] As an optional implementation, the calculation formula of the deflection angle is specifically:

[0060]

[0061] Where R represents the signal amplitude representing the center coordinate of the light spot; T represents the measurement period; R i Indicates the amplitude information obtained at the i-th sampling time; u i represents the rotation angle of the rotating stage 107 acquired at the i-th sampling.

[0062] As another optional implementation, considering the influence of the accuracy of the measuring instrument, the calibration coefficient can be determined through historical measurement data, and the calculation formula of the deflection angle is specifically:

[0063]

[0064] Where R represents the signal amplitude representing the center coordinate of the light spot; T represents the measurement period; R i Indicates the amplitude information obtained at the i-th sampling time; u i represents the rotation angle of the rotating stage 107 obtained at the i-th sampling; K represents the calibration coefficient, which is determined by the measuring instrument.

[0065] In order to reduce the error caused by the instrument and make the whole measurement result more stable and reliable, the amplitude information can be preprocessed. The specific process is: obtain the continuous amplitude information within a single sampling period; sort the continuous amplitude information; filter the preset percentage of amplitude information in the front and back columns of the sorting; calculate the mean of the remaining amplitude information to obtain the final amplitude information. For example, filter out the data in the first and last quarters of the sorting.

[0066] like Figure 3 As shown in the figure, based on the previous experimental results, the optimal experimental conditions were selected, and an experimental accuracy of 1.99" was obtained by continuously measuring 25 sets of test data, which has high stability. In addition, the measurement method can replace the infrared focal plane camera to test the refractive index of infrared materials, and the single-point centroid aiming algorithm can make the aiming accuracy close to 2".

[0067] Working principle: The present invention uses a single-point detector to continuously characterize the signal amplitude of the center coordinates of the light spot, and combines the rotation angle of the rotating table 107 to perform enhanced average calculation. The entire measurement process does not require a self-collimating light tube for control processing. The optical path of the measurement process is relatively simple, the measurement accuracy and effect are high, and the application cost is low. The single-point detector and related algorithms are used to achieve continuous measurement of the deflection angle of the test prism, which has a lower application cost than the traditional application of array detectors.

[0068] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0069] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0070] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0071] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0072] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low-temperature infrared material refractive index measuring device based on single-point detection, characterized in that: include: An infrared light source assembly, used for outputting infrared light of a preset wavelength; A rotating table (107) is placed in the vacuum thermostat (106) and synchronously adjusts the rotation angle of the test prism during rotation; A beam splitter (105), wherein the infrared light passes through the beam splitter (105) and is transmitted to the test prism, and the beam splitter (105) reflects and outputs the light that returns along the original path after being reflected by the reflective film on the back of the test prism; A sighting device (108) acquires, through a single-point detector, a signal amplitude representing the coordinates of the center of the light spot that changes with the rotation angle of the test prism; The processor is used to calculate the deflection angle of the test prism after adjusting the rotation angle by a weighted average method according to the signal amplitude and the rotation angle of the rotating platform (107), and determine the refractive index at the current temperature according to the deflection angle.

2. The low-temperature infrared material refractive index measuring device based on single-point detection according to claim 1 is characterized in that: The infrared light source assembly comprises an infrared monochromator (101), a high-temperature cavity black body (102), a chopper disk, an off-axis mirror (103) and a plane mirror (104); The divergent monochromatic light emitted from the outlet slit of the infrared monochromator (101) is converted into collimated parallel light by an off-axis mirror (103), and then reflected by a plane mirror (104) and emitted into a test prism.

3. The low-temperature infrared material refractive index measuring device based on single-point detection according to claim 1 is characterized in that: The wavelength of the infrared light ranges from 2um to 14um.

4. The low-temperature infrared material refractive index measuring device based on single-point detection according to claim 1 is characterized in that: The beam splitter (105) is a semi-transparent and semi-reflective mirror.

5. The low-temperature infrared material refractive index measuring device based on single-point detection according to claim 1 is characterized in that: The aiming device (108) is equipped with a preamplifier and a lock-in amplifier; When the infrared light is focused on the center of the photosensitive surface of the single-point detector, it is amplified by a preamplifier and output after being processed by a phase-locked amplifier to determine the signal amplitude that represents the maximum position of the light beam output signal.

6. A method for measuring the refractive index of low-temperature infrared materials based on single-point detection, characterized in that: The following steps are involved: S1: Output infrared light of a preset wavelength through an infrared light source component; S2: placing the rotating stage (107) in the vacuum thermostat (106), and synchronously adjusting the rotation angle of the test prism during the rotation; S3: The infrared light passes through the beam splitter (105) and is transmitted to the test prism, and the beam splitter (105) reflects and outputs the light that returns along the original path after being reflected by the reflective film on the back of the test prism; S4: obtaining, through a single-point detector, a signal amplitude representing the coordinates of the center of the light spot that changes with the rotation angle of the test prism; S5: According to the signal amplitude and the rotation angle of the rotating platform (107), the deflection angle of the test prism after the rotation angle is adjusted is calculated by a weighted average method, and the refractive index at the current temperature is determined according to the deflection angle.

7. The method for measuring the refractive index of low-temperature infrared materials based on single-point detection according to claim 6 is characterized in that: The calculation formula of the deflection angle is specifically: Where R represents the signal amplitude representing the center coordinate of the light spot; T represents the measurement period; R i Indicates the amplitude information obtained at the i-th sampling time; u i represents the rotation angle of the rotating stage (107) obtained at the i-th sampling.

8. The method for measuring the refractive index of low-temperature infrared materials based on single-point detection according to claim 6 is characterized in that: The calculation formula of the deflection angle is specifically: Where R represents the signal amplitude representing the center coordinate of the light spot; T represents the measurement period; R i Indicates the amplitude information obtained at the i-th sampling time; u i represents the rotation angle of the rotating stage (107) obtained at the i-th sampling; K represents the calibration coefficient, which is determined by the measuring instrument.

9. The method for measuring the refractive index of low-temperature infrared materials based on single-point detection according to claim 7 or 8, characterized in that: The process of obtaining the amplitude information is specifically as follows: Obtain continuous amplitude information within a single sampling period; Sort the continuous amplitude information; Filter the amplitude information of the preset percentage of the sorted columns and the sorted columns; Calculate the mean of the remaining amplitude information to obtain the final amplitude information.

10. The method for measuring the refractive index of low-temperature infrared materials based on single-point detection according to claim 9, characterized in that: The preset percentage is 20%-25%.

Images