Wide dynamic range and ultra-high uniformity spectral irradiance light source

Abstract

The present invention provides a wide dynamic range ultra-high uniformity spectral irradiance light source, including a light source generation subsystem, a storage space, a built-in stray light elimination aperture tube, an external stray light elimination aperture tube, a multifunctional circuit box, a mobile Formosa wheel and a box; the light source generation subsystem includes a sub-integrating sphere, a halogen tungsten light source, a programmable adjustable electric aperture, a main integrating sphere and a monitoring detector module. The present invention is a uniform light system based on a cascade integrating sphere, which can generate a wide range of dynamically adjustable irradiance in the light output area, and ensure stable illumination with ultra-high surface uniformity, and is suitable for the calibration requirements of large detectors.

Description

Technical Field

[0001] The invention belongs to the field of spectral radiation measurement correction, and in particular relates to a spectral irradiance light source with a wide dynamic range and ultra-high uniformity. Background Art

[0002] Remote sensors in the aerospace field usually need to be calibrated first to establish a quantitative relationship between the actual radiance received by the remote sensor and the digital output, so that the exposure time of the detector and the gain of its amplifier can be adjusted in a targeted manner. Through reasonable calibration work, aerospace remote sensors can obtain accurate observation images for detection targets of different radiances and achieve the best detection effect.

[0003] In the high-precision optical measurement project for the detection of extrasolar planetary systems, it is necessary to carry out high-precision positioning measurements of all approximately 100 stars near the solar system. Since large telescopes are mostly used in the project, large telescopes are composed of multiple pixels of multiple detectors, and the detection band is the visible light band. In order to solve the measurement and correction of illumination response uniformity and response nonlinearity of scientific-grade large-size back-illuminated image sensors, response instability calibration, and provide design and data support for pixel-star spacing measurement technology, it is necessary to develop a stable ultra-high uniformity light source for large detector calibration.

[0004] As a widely used uniform radiation light source, the integrating sphere is a hollow sphere with a highly reflective inner surface. The incident light is reflected multiple times on the diffuse reflection layer of the inner wall until the luminous flux of the entire inner surface of the sphere is consistent, so that the light output at the outlet of the integrating sphere has good surface uniformity. Its good spectral radiation adjustment ability and uniform radiant brightness output make it widely used in the field of optical sensor calibration. The larger the light outlet opening of the integrating sphere, the more serious its edge effect. At present, when the diameter of the light outlet of the commercial integrating sphere reaches 50mm, the non-uniformity of the light outlet surface reaches 2% to 3%, which does not meet the 0.2% calibration accuracy required by large detectors. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a wide dynamic range and ultra-high uniformity spectral irradiance light source, which is a uniform light system based on cascaded sub- and mother integrating spheres, which can produce a wide range of dynamically adjustable irradiance in the light output area and ensure stable illumination with ultra-high surface uniformity, and is suitable for the calibration requirements of large detectors.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A wide dynamic range ultra-high uniformity spectral irradiance light source, comprising a light source generation subsystem, a storage space, a built-in stray light elimination aperture cylinder, an external stray light elimination aperture cylinder, a multifunctional circuit box, a movable Formosa wheel and a box body; the light source generation subsystem comprises a sub-integrating sphere, a halogen tungsten lamp light source, a programmable adjustable electric aperture, a main integrating sphere and a monitoring detector module; the halogen tungsten lamp light source is fixed on the side of the sub-integrating sphere, and the bottom light outlet of the halogen tungsten lamp light source is connected to the programmable adjustable electric aperture; the programmable adjustable electric aperture is fixed on the main integrating sphere Aperture, the monitoring detector module is fixed at the small light emitting hole on the front side, and the light outlet on the right side is connected to the built-in stray light elimination aperture cylinder; the built-in stray light elimination aperture cylinder is connected to the external stray light elimination aperture cylinder through the wall of the box body to form a direct lighting light path part; a multifunctional circuit box fixed on the bottom plate of the box body is placed below the built-in stray light elimination aperture cylinder, and a partition is provided above it, and the space separated by the partition is a storage space for placing the removed external stray light elimination aperture cylinder; four movable Forma wheels are installed below the bottom plate of the box body.

[0008] Furthermore, a halogen tungsten lamp is used as the light source, and multiple light homogenization is performed by cascading a sub- and main integrating sphere. The luminous flux entering the main integrating sphere from the sub-integrating sphere is adjusted by a programmable adjustable electric aperture. The light emitted from the light outlet of the main integrating sphere enters a direct illumination light path composed of a built-in stray light elimination aperture tube and an external stray light elimination aperture tube, and the light source is output at the external stray light elimination flange.

[0009] Furthermore, the programmable adjustable electric aperture includes an upper cover plate for the light entrance hole, a slide rail, a light-shielding aperture piece, a lower cover plate for the light exit hole, a voice coil motor, and an adjustment gasket; the voice coil motor drives the light-shielding aperture piece to perform linear motion, thereby realizing a reciprocating linear motion process of the light-shielding aperture piece, and a slide rail is arranged at each of the left and right ends of the light-shielding aperture piece to provide a vertical upward support force to offset its gravity; the voice coil motor is placed perpendicular to the horizontal plane, and an adjustment gasket is arranged below it, and the adjustment gasket is placed horizontally by adjusting the height at the four fixed holes of the adjustment gasket; the edge of the light-shielding aperture piece has a light-blocking structure to block the diffusely reflected light in the cavity from entering the light exit; the extinction structure at the light exit of the lower cover plate of the light exit hole is composed of multiple layers of flexible black cloth for eliminating stray light; the flexible black cloth is arranged in an orderly manner, and a lubricant is applied to the contact between the flexible black cloth and the light-shielding aperture piece.

[0010] Furthermore, the monitoring detector module includes a cover, a circuit board pressure ring, a photoelectric detector and a circuit board module, a detector tube, an aperture plate, an attenuation plate and an attenuation plate pressing block; the monitoring detector module detects the light source on the opening area of ​​the sphere through a hole in the side of the mother integrating sphere, and attenuates the light source through the attenuation plate, thereby measuring the irradiance value of the light source at the outlet of the mother integrating sphere; the detector tube and the aperture plate both have grooves for installing rubber sealing rings to achieve moisture-proof sealing and eliminate environmental stray light; the captured light source signal is converted into a current signal by the silicon photodiode in the photoelectric detector and the photoelectric detector in the circuit board module, and enters the transimpedance amplifier to convert the 10pA level current signal into a voltage signal, and then the AD acquisition module converts the analog voltage signal into a digital signal, which is sent to the multifunctional circuit box for signal processing, and then transmitted to the computer program to realize the function of real-time monitoring of the irradiance of the mother integrating sphere.

[0011] Furthermore, based on the principle of direct illumination optical path, a direct illumination optical path consisting of a built-in stray light diaphragm tube and an external stray light diaphragm tube was constructed. The inner cavity of the direct illumination optical path was sprayed with a high light absorption ratio matte paint, and a multi-level stray light diaphragm was used to reduce the stray light reflected in the cavity. The built-in stray light diaphragm tube and the external stray light diaphragm tube also play a role in isolating the interference of external ambient light.

[0012] Furthermore, the multifunctional circuit box includes a power driving circuit board, a multi-channel signal collector, a halogen tungsten lamp driving module and a voice coil motor programmable VI module; the signal is sent to the multi-channel signal collector for filtering and then output to the computer software through the USB port to observe the waveform diagram and the corresponding numerical value; the power driving circuit board is used for power supply, converting 220V AC power into DC power; the halogen tungsten lamp driving module converts the digital signal into a voltage analog signal output to provide voltage input for the voltage-controlled constant current module; a voltage follower is designed in the voltage-controlled constant current module to be connected with a sampling resistor to isolate the input voltage and output current; the voice coil motor programmable VI module gives precise voltage and current values ​​to stably drive the voice coil motor.

[0013] Furthermore, the internal structure of the light source is compact, and the external stray light elimination aperture tube is detachable and can be placed in the storage space after being removed; the external shape of the light source is regular, which is convenient for transportation and handling.

[0014] Furthermore, the movable Foma wheel can adjust the height up and down and can be easily fixed.

[0015] Beneficial effects:

[0016] (1) The halogen tungsten lamp light source of the present invention achieves the light intensity stability of 99.99% / h for up to two hours after being turned on for half an hour by precisely driving the color temperature and current through the halogen tungsten lamp driving module, thus ensuring the stability of the light source output irradiance during the calibration process, and providing a guarantee for the ultra-high uniformity of the present invention. It meets the calibration requirements for the response stability of large detectors in the visible light band and the time required to complete various calibrations.

[0017] (2) The programmable adjustable electric diaphragm of the present invention can achieve precise control of radiance by blocking the light exit hole. Thus, the irradiance output range is 1×10 -3 ~10 2 μW / cm 2 . It meets the irradiance calibration requirements of large detectors in the visible light band in five irradiance measurement ranges.

[0018] (3) The monitoring detector module of the present invention monitors the irradiance of the mother integrating sphere in real time and transmits the irradiance output data to the computer acquisition program. Then, by controlling the programmable adjustable electric aperture, the irradiance output is programmably adjusted, meeting the calibration requirements of the response nonlinear adjustment required by large detectors in the visible light band.

[0019] (4) The cascaded sub- and main integrating spheres and the direct illumination optical path of the present invention achieve a surface uniformity of more than 99.9% within a 40 mm diameter light spot center at 0 to 10 mm in the axial direction of the external stray light elimination flange outlet, thus solving the most important surface uniformity calibration problem of large detectors in the visible light band.

[0020] (5) The present invention is easy to transport, not easy to damage, easy to move and fix, compact in size, and light in weight, and can be adapted to various calibration experimental environments such as indoor laboratories and outdoor calibration sites.

[0021] The present invention particularly relates to the measurement and correction of response uniformity and response nonlinearity over five magnitude ranges of illumination for scientific-grade large-size back-illuminated image sensors, and response instability calibration, providing design and data support for deep space exploration projects such as research on micro-pixel intersatellite spacing measurement technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall layout of a system of a wide dynamic range ultra-high uniformity spectral irradiance light source of the present invention;

[0023] Figure 2 This is a schematic diagram of the light source generation subsystem of the present invention;

[0024] Figure 3 A schematic diagram of a programmable adjustable electric diaphragm for adjusting the spectral irradiance intensity range in the light source generation subsystem of the present invention;

[0025] Figure 4 A schematic diagram of the details of the electric aperture stray light elimination structure in the present invention;

[0026] Figure 5 A schematic diagram of the simplified structure of the direct illumination light path behind the light outlet of the present invention;

[0027] Figure 6 It is a schematic diagram of the mechanical structure of the illumination optical path of the present invention;

[0028] Figure 7 This is a schematic diagram of the structure of a stray light elimination diaphragm tube built into the illumination light path;

[0029] Figure 8 It is a schematic diagram of the structure of an external stray light elimination aperture tube in the illumination light path;

[0030] Fig. 9 It is a schematic diagram of the structure of the monitoring detector module;

[0031] Fig.10 It is a schematic diagram of the structure of a multifunctional circuit box.

[0032] Among them: sub-integrating sphere 1, halogen tungsten light source 2, programmable adjustable electric aperture 3, main integrating sphere 4 and monitoring detector module 5, storage space 6, built-in stray light elimination aperture cylinder 7, external stray light elimination aperture cylinder 8, multifunctional circuit box 9, mobile Forma wheel 10;

[0033] The light entrance upper cover plate 31, the ball bearing linear guide rail 32, the light shielding aperture plate 33, the light exit lower cover plate 34, the voice coil motor 35, and the adjustment gasket 36;

[0034] The mother integrating sphere flange 71, the adapter flange 72, the electric aperture piece 73, three pluggable aperture pieces 74, the inner aperture tube upper cover plate 75, two inner aperture tube side plates 76, and the inner aperture tube bottom plate 77;

[0035] Adapter flange 81, three pluggable fixed diaphragms 82, a short upper cover plate 83, an adjustable electric diaphragm 84, a second light outlet flange 85, two short reinforcing rib side plates 86, and a short lower bottom plate 87;

[0036] Cover 91, circuit board pressing ring 92, photoelectric detector and circuit board module 93, detector tube 94, aperture piece 95, attenuation piece 96, attenuation piece pressing block 97;

[0037] A power drive circuit board 101 , a multi-channel signal collector 102 , a halogen lamp drive module 103 and a voice coil motor programmable VI module 104 . DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] The wide dynamic range ultra-high uniformity spectral irradiance light source of the present invention can help large-size detectors to measure and correct response uniformity and response nonlinearity, as well as perform response instability calibration.

[0040] like Figure 1 , Figure 2 As shown, the wide dynamic range ultra-high uniformity spectral irradiance light source of the present invention includes a light source generating subsystem, a storage space 6, a built-in stray light elimination aperture cylinder 7, an external stray light elimination aperture cylinder 8, a multifunctional circuit box 9, a mobile form wheel 10 and a box. Figure 2 As shown, the light source generation subsystem includes a sub-integrating sphere 1, a halogen tungsten lamp light source 2, a programmable adjustable electric diaphragm 3, a main integrating sphere 4 and a monitoring detector module 5. It should be understood that the number of the sub-integrating sphere 1 and the halogen tungsten lamp light source 2 can be 1, 2 or 3, and the sub-integrating sphere 1 can be located on the remaining free mounting surface. It should also be understood that the monitoring detector module 5 can be multiple or the monitoring detector module 5 can be eliminated. The halogen tungsten lamp light source 2 is fixed on the side of the sub-integrating sphere 1, and the bottom light outlet of the halogen tungsten lamp light source 2 is connected to the programmable adjustable electric diaphragm 3. The programmable adjustable electric diaphragm 3 is fixed on the main integrating sphere 4, the monitoring detector module 5 is fixed to the light outlet of the front side, and the built-in stray light elimination diaphragm tube 7 is connected to the light outlet of the right side. The built-in stray light elimination diaphragm tube 7 is connected to the external stray light elimination diaphragm tube 8 through the box wall to form a direct illumination light path part. A multifunctional circuit box 9 fixed on the bottom plate of the box is placed below the built-in stray light elimination aperture tube 7, and a partition is provided on it. The space separated by the partition is a storage space 6, which is used to place the removed external stray light elimination aperture tube 8. Four movable Foma wheels 10 are installed under the bottom plate of the box. The movable Foma wheels 10 have the advantages of adjusting the height up and down and convenient fixing, which is convenient for transportation and experimental fixing. The arrangement of the box cleverly utilizes the space in the instrument. The overall shape is a rectangular parallelepiped during transportation, which has the advantages of not easy to damage, compact size, and convenient transportation.

[0041] The multifunctional circuit box 9 is powered by 220V AC, and the preset current value signal is input by the computer software to transmit the corresponding current to the halogen tungsten lamp light source 2. The power drive module can provide a stable DC current to keep the color temperature and output radiation of the halogen tungsten lamp stable.

[0042] The light generated by the halogen tungsten light source 2 enters the sub-integrating sphere 1, and the light is diffusely reflected multiple times by the white polytetrafluoroethylene coating on its inner surface, and is homogenized to improve the surface uniformity. Then the light source enters the square entrance of the programmable adjustable electric diaphragm 3. Figure 3 As shown, the programmable adjustable electric diaphragm 3 includes an upper cover plate 31 for the light entrance, a ball linear guide rail 32, a light shielding diaphragm piece 33, a lower cover plate 34 for the light exit, a voice coil motor 35, and an adjustment gasket 36. Its working process is: the voice coil motor 35 drives the light shielding diaphragm piece 33 to move linearly, so as to realize the reciprocating linear motion process of the light shielding diaphragm piece 33. The voice coil motor 35 has the advantages of sensitive response, smooth movement, direct drive, simple structure and small volume, and meets the requirements of rapid adjustment, precision and accuracy required for the spectral irradiance adjustment of the light source. The preferred solution of the programmable adjustable electric diaphragm 3 is that the stroke is 20mm, the step resolution is better than 1μm, and the repeatability is better than 2μm. However, due to the small thrust of the voice coil motor 35, the load driven by the voice coil motor 35 cannot be too heavy, so a ball linear guide rail 32 is arranged at the left and right ends of the light shielding diaphragm piece 33 to provide a vertical upward support force to offset its gravity. The voice coil motor 35 only needs to overcome the very small rolling friction in the ball linear guide 32, which greatly reduces the load driven by the voice coil motor 35. This design ensures the motion characteristics of the voice coil motor 35, such as sensitive response and smooth movement. Because the driving force of the voice coil motor 35 is small and it is easily affected by gravity, the voice coil motor 35 needs to be placed parallel to the horizontal plane and the inclination angle cannot be greater than 45°. Therefore, an adjustment gasket 36 is arranged under the voice coil motor 35, and the voice coil motor 35 can be placed horizontally by adjusting the height of the four fixed holes of the adjustment gasket 36. It should be understood that the voice coil motor used in the present invention can also be replaced by a servo motor of a linear push rod.

[0043] like Figure 4 As shown, the principle of the stray light elimination structure of the programmable adjustable electric diaphragm 3 is that the light from the light source passes through the upper cover plate 31 of the light entrance hole and enters the programmable adjustable electric diaphragm 3. The main purpose of the stray light elimination structure is to prevent stray light from entering the light exit when the programmable adjustable electric diaphragm 3 is closed, thereby reducing the lower limit of irradiance adjustment. Figure 4As shown in the figure, when the program-adjustable electric diaphragm 3 is closed, stray light has two paths to enter the light outlet: ① the light reflected by the inner wall is reflected again through the bottom and enters the light-blocking part of the light-shielding diaphragm piece 33; ② the light enters from the light-exiting diaphragm hole of the light-shielding diaphragm piece 33 and then enters the light-blocking part through the bottom reflection. According to basic optical knowledge, the latter has one less reflection, so the ② path is the main stray light source. The light-blocking part of the light-shielding diaphragm piece 33 is designed to be only 0.1mm away from the bottom, which basically blocks 95% of the stray light in the ① method. Then, three double-sided matte black cloths with an extinction ratio of 90% are adhered with black silicone at a distance of 1mm near the diaphragm hole to perform three-level extinction. Since the three black cloths A, B, and C are flexible cloths, they can directly contact the light-shielding diaphragm piece 33. Lubricant is applied to the contact area between the cloth and the light-shielding diaphragm piece 33, so that the light outlet is isolated from light, and the isolation of stray light can reach 0.001%. The entire program-adjustable electric diaphragm 3 is internally sprayed with a preferred extinction paint with an extinction ratio of 95% to absorb the stray light reflected by the shading diaphragm piece 33 and the internal cavity. The light outlet is preferably a square with two diagonals of 16 mm each, the purpose of which is to make the irradiance adjustment curve basically linear and facilitate irradiance adjustment. The voice coil motor 35 drives the shading diaphragm piece 33 to move at the square light outlet of the sub-integrating sphere 1, so that the illumination range at the outlet of the external stray light elimination diaphragm tube 8 covers 1×10 -3 ~10 2 μW / cm 2 , achieving a linear adjustment range of five orders of magnitude. Afterwards, the light source enters the mother integrating sphere 4 for the second light homogenization process, and the inner surface of the mother integrating sphere 4 is also sprayed with white polytetrafluoroethylene, which further improves the uniformity of the light source.

[0044] A monitoring detector module 5 is fixed on the side of the mother integrating sphere 4. Fig. 9 As shown, the monitoring detector module 5 includes a cover 91, a circuit board pressing ring 92, a photoelectric detector and circuit board module 93, a detector tube 94, an aperture plate 95, an attenuation plate 96, and an attenuation plate pressing block 97. The monitoring detector module 5 detects the light source on the opening area of ​​the mother integrating sphere 4 through the opening on the side of the detection sphere, and attenuates the light source through the attenuation plate 96, so as to measure the irradiance value of the light source at the outlet of the mother integrating sphere 4. The detector tube 94 and the aperture plate 95 both have grooves for installing rubber sealing rings for moisture-proof sealing and eliminating environmental stray light. The field of view angle of the photoelectric detector in the photoelectric detector and circuit board module 93 is set to 30°, the field of view solid angle Ω is 0.5, and the receiving power range is 2.3×10 -5~0.23μW. After analysis, the monitoring detector module 5 is within the effective linear response power range. The signal-to-noise ratio can be obtained by calculating the ratio of the light power received by the photodetector to the equivalent noise power. At present, the equivalent noise power that can be achieved by the photodetector, transimpedance amplifier, and data acquisition modules is 100fW, so the signal-to-noise ratio can be guaranteed to be better than 1000:1. The captured light source signal is converted into a current signal by the silicon photodiode in the photodetector, and enters the transimpedance amplifier to convert the 10pA current signal into a voltage signal. Afterwards, the AD acquisition module converts the analog voltage signal into a digital signal, sends it to the multi-functional circuit box 9 for signal processing, and then transmits it to the computer program to realize the function of real-time monitoring of the irradiance of the mother integrating sphere 4.

[0045] like Fig.10 As shown, the multifunctional circuit box 9 includes a power driver circuit board 101, a multi-channel signal collector 102, a halogen lamp driver module 103 and a voice coil motor programmable VI module 104. The multifunctional circuit box 9 adopts a modular design, and each module is shielded, which basically isolates the occurrence of signal crosstalk. The above signal is sent to the multi-channel signal collector 102 for filtering, and then output to the computer software through the USB port to observe the waveform and the corresponding value. The power driver circuit board 101 mainly supplies power to the remaining circuits, which converts 220V AC into DC. The halogen lamp driver module 103 converts the digital signal into a voltage analog signal output and provides a voltage input for the voltage-controlled constant current module. The voltage follower is designed in the voltage-controlled constant current module to connect with the sampling resistor to isolate the input voltage and output current and reduce mutual influence. The low offset voltage drift and low noise operational amplifier OPA2241 is selected as the core component of the voltage-controlled constant current module to improve the stability performance. The stability of the halogen tungsten lamp reaches an ultra-high stability of 99.99% / h after half an hour, which can be maintained for two hours. The spectral range covers 400nm to 900nm. The voice coil motor programmable VI module 104 gives precise voltage and current values ​​to stably drive the voice coil motor, and through 100000:1 programmable adjustment, the preferred design is a stroke of 20mm, a step resolution better than 1μm, and a repeatability better than 2μm.

[0046] The light source of the light outlet of the mother integrating sphere 4 enters the direct illumination light path. The schematic diagram of the direct illumination light path principle is as follows: Figure 5 As shown. On the left is a uniform radiation source composed of cascaded mother and child integrating spheres, and on the right is a large-scale aerospace array detector in the visible light band that needs to be calibrated. The horizontal distance between the two is x, and the diameter of the integrating sphere is D, L Sis the spectral radiance output by the integrating sphere port, θ is the angle between the straight line from the edge of the light outlet to the center of the array detector and the optical axis of the illumination light path, and φ represents the angle between the straight line from the edge of the array detector to the center of the light outlet plane and the optical axis of the illumination light path. Direct illumination light path ratio coefficient r xd =x / D, determines the detector edge irradiance E e and the central irradiance E 0 The ratio of r also affects the uniformity index of the calibration light source at the detector. xd The output light source can obtain higher surface uniformity, but the light intensity will also be attenuated. xd The value is 20, x is 1000mm, and D is 50mm. It should be understood that r xd It can also take a value between 5 and 30. Similarly, the values ​​of x and D can also be appropriately adjusted according to the ratio.

[0047] The direct illumination optical path principle of the wide dynamic range ultra-high uniformity spectral irradiance light source of the present invention is as follows:

[0048] E 0 =πL s sin 2 θ (1)

[0049]

[0050] Let r xd =x / D, then:

[0051]

[0052] E e =E 0 cos 4 φ (4)

[0053] When θ=φ,

[0054]

[0055] According to the above principle, when r xd When the value is 20, x is 1000 mm, and D is 50 mm, the output irradiance stability of the present invention is maintained at 99.99% / h for two hours after being turned on for half an hour at a distance of 0 to 10 cm from the outlet of the second light outlet flange 85 of the external stray light elimination device, and the surface uniformity is maintained at 99.9% (within a spot diameter of 40 mm), and the irradiance value range is within 1×10 -3 ~10 2 μW / cm 2 , circular light spot with a diameter of 0 to 50 mm.

[0056] If the lighting optical path is directly exposed, the ambient stray light will reduce the uniformity of the light source output. Therefore, the optical path must be protected. The overall optical path structure should be as follows: Figure 6 The light source is emitted from the cascaded child and mother integrating spheres, enters the built-in stray light elimination aperture tube 7, and then enters the external stray light elimination aperture tube light source 8, and finally outputs the light source.

[0057] like Figure 7 As shown, the built-in stray light elimination diaphragm tube 7 as a whole adopts four pieces of aluminum plates of the preferred model 2A12 fixed together by screws, and the built-in stray light elimination diaphragm tube 7 includes an inner diaphragm tube upper cover plate 75, two inner diaphragm tube side plates 76, and an inner diaphragm tube bottom plate 77. The four aluminum plates are uniformly interference fit to ensure that there is no interference from ambient light. The inner wall of the built-in stray light elimination diaphragm tube 7 is sprayed with a preferred extinction ratio coefficient of 95% extinction black paint. The multi-stage stray light elimination diaphragm is composed of a mother integrating sphere flange 71, an adapter flange 72, an electric diaphragm piece 73, three pluggable diaphragm pieces 74 and a first light outlet flange 78. The built-in multi-stage stray light elimination diaphragm has a total of 7 levels, and the preferred diaphragm diameter is 52mm, and the diaphragm tube optical path length is 600mm. Through the multi-stage stray light elimination aperture and the absorption of the black paint surface in the tube, the illumination light path of the present invention is not affected by the ambient stray light, and the phenomenon of the surface uniformity being reduced due to the reflection superposition of the light source propagation angle divergence in the cavity is avoided. It should be understood that the built-in stray light elimination aperture tube 7 can also be other shapes such as circular, elliptical, polygonal, etc., and the material can also be other metals or plastics.

[0058] like Figure 8 As shown, the external stray light elimination aperture tube 8 and the internal stray light elimination aperture tube 7 have similar structures, and mainly play the role of extending the light path and improving the proportional coefficient r xd ratio, which improves the uniformity of the light source surface at the light outlet. Its cavity includes two short reinforcing rib side panels 86, a short upper cover plate 83, and a short lower bottom plate 87. Its multi-stage stray light elimination structure includes a transfer flange 81, three pluggable fixed diaphragms 82, an adjustable electric diaphragm 84, and a second light outlet flange 85. Its principle and function are the same as those of the built-in stray light elimination diaphragm tube 7, and a 6-stage stray light elimination tube diaphragm is adopted. The diaphragm diameter is 52mm, and the diaphragm tube optical path length is 400mm. It should be understood that the external stray light elimination diaphragm tube 8 can be disassembled. If the optical path does not need to be extended, it can be removed and installed in the storage space 6 on the light source system.

[0059] The internal and external stray light elimination aperture tube 7 and the external stray light elimination aperture tube 8 absorb most of the divergent light due to the propagation angle of the light source through the multi-level extinction of the internal and external 13-level apertures and the 1000mm long optical path, avoiding the phenomenon of high irradiance in the center of the output light source surface and improving the surface uniformity of the light source output.

[0060] Large detectors that need to be calibrated can be calibrated at 0 to 10 cm from the end of the external stray light elimination aperture tube 8, perpendicular to the normal line of the light outlet, to achieve an ideal calibration effect. The present invention can complete the measurement and calibration of the surface uniformity, response nonlinearity, polarization sensitivity, and response instability of large-scale back-illuminated image sensors, which are very important for space exploration, and provide design and data support for the research of micro-pixel intersatellite measurement technology. At the same time, the present invention has a compact and simple structure, is easy to transport and stable, and can meet the calibration tasks of large detectors in a variety of complex situations.

[0061] The embodiments described above are only preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A wide dynamic range ultra-high uniformity spectral irradiance light source, characterized in that: It comprises a light source generating subsystem, a storage space, a built-in stray light eliminating diaphragm tube, an external stray light eliminating diaphragm tube, a multifunctional circuit box, a movable Forma wheel and a box body; the light source generating subsystem comprises a sub-integrating sphere, a halogen tungsten lamp light source, a programmable adjustable electric diaphragm, a main integrating sphere and a monitoring detector module; the halogen tungsten lamp light source is fixed on the side of the sub-integrating sphere, and the bottom light outlet of the halogen tungsten lamp light source is connected to the programmable adjustable electric diaphragm; the programmable adjustable electric diaphragm is fixed on the main integrating sphere, the monitoring detector module is fixed to the light outlet of the front side, and the built-in stray light eliminating diaphragm tube is connected to the light outlet of the right side; the built-in stray light eliminating diaphragm tube is connected to the external stray light eliminating diaphragm tube through the box body wall to form a direct lighting optical path part; A multifunctional circuit box fixed on the bottom plate of the box is placed below the built-in stray light elimination diaphragm tube, and a partition is provided above the multifunctional circuit box. The space separated by the partition is a storage space for placing the removed external stray light elimination diaphragm tube. Four movable Forma wheels are installed below the bottom plate of the box. Halogen tungsten lamp is used as the light source, and multiple light homogenization is performed by cascading the sub-integrating sphere and the main integrating sphere. The light flux from the sub-integrating sphere to the main integrating sphere is adjusted by the programmable adjustable electric aperture. The light emitted from the light outlet of the main integrating sphere enters the direct illumination light path composed of the built-in stray light elimination aperture cylinder and the external stray light elimination aperture cylinder, and the light source is output at the external stray light elimination flange. The programmable adjustable electric diaphragm comprises an upper cover plate for a light entrance hole, a slide rail, a light shielding diaphragm piece, a lower cover plate for a light exit hole, a voice coil motor, and an adjustment gasket; the voice coil motor drives the light shielding diaphragm piece to perform a linear motion, so as to realize a reciprocating linear motion process of the light shielding diaphragm piece; a slide rail is arranged at each of the left and right ends of the light shielding diaphragm piece to provide a vertical upward supporting force to offset its gravity; The voice coil motor is placed perpendicular to the horizontal plane, and an adjusting gasket is arranged below it. The adjusting gasket can be placed horizontally by adjusting the height of the four fixed holes. The edge of the light-shielding aperture piece has a light-blocking structure to block the diffusely reflected light in the cavity from entering the light outlet. The extinction structure at the light outlet under the light outlet cover is composed of multiple layers of stray light-eliminating flexible black cloth. The flexible black cloth is arranged in an orderly manner, and lubricant is applied to the contact between the flexible black cloth and the light-shielding aperture piece.

2. The wide dynamic range ultra-high uniformity spectral irradiance light source according to claim 1, characterized in that: The monitoring detector module includes a cover, a circuit board pressure ring, a photoelectric detector and a circuit board module, a detector tube, an aperture plate, an attenuation plate and an attenuation plate pressing block; the monitoring detector module detects the light source on the opening area in the sphere by opening a hole on the side of the mother integrating sphere, and the light source is attenuated by the attenuation plate, so as to measure the irradiance value of the light source at the outlet of the mother integrating sphere; the detector tube and the aperture plate are both provided with grooves for installing rubber sealing rings for moisture-proof sealing and eliminating environmental stray light; the captured light source signal is converted into a current signal by the silicon photodiode in the photoelectric detector and the circuit board module, and enters the transimpedance amplifier to convert the 10 pA level current signal into a voltage signal, and then the AD acquisition module converts the analog voltage signal into a digital signal, which is sent to the multifunctional circuit box for signal processing, and then transmitted to the computer program to realize the function of real-time monitoring of the irradiance of the mother integrating sphere.

3. The wide dynamic range ultra-high uniformity spectral irradiance light source according to claim 1, characterized in that: The inner cavity of the direct illumination light path is sprayed with matte paint with high light absorption ratio, and a multi-level stray light elimination aperture is used to reduce the stray light reflected in the cavity; the built-in stray light elimination aperture tube and the external stray light elimination aperture tube isolate the external ambient light.

4. The wide dynamic range ultra-high uniformity spectral irradiance light source according to claim 1, characterized in that: The multifunctional circuit box comprises a power driving circuit board, a multi-channel signal collector, a halogen tungsten lamp driving module and a voice coil motor program-controlled VI module; the signal is sent to the multi-channel signal collector for filtering and then output to the computer software through the USB port so as to observe the waveform diagram and the corresponding numerical value; the power driving circuit board is used for power supply and converts 220V alternating current into direct current; the halogen tungsten lamp driving module converts the digital signal into a voltage analog signal output and provides voltage input for the voltage-controlled constant current module; the voltage follower in the voltage-controlled constant current module is connected to the sampling resistor to isolate the input voltage and output current; the voice coil motor program-controlled VI module stably drives the voice coil motor by giving precise voltage and current values.

5. The wide dynamic range ultra-high uniformity spectral irradiance light source according to claim 1, characterized in that: The internal structure of the light source is compact, and the external stray light elimination aperture tube is detachable and can be placed in the storage space after being detached; the external shape of the light source is regular, and is convenient for transportation and handling.

6. The wide dynamic range ultra-high uniformity spectral irradiance light source according to claim 1, characterized in that: The movable Foma wheel can adjust the height up and down and is convenient to fix.

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