CN106872026A - Adjustable faint light generating apparatus - Google Patents

Abstract

An embodiment of the present invention relates to an adjustable weak light generating device, comprising: a light source, used to output incident light; The luminous flux of the described incident light of dimmer stop; Integrating sphere, described integrating sphere comprises entrance port, exit port, shield screen and photodetector, and described photodetector output detects photoelectric current; Programmable photometer, with described The photodetectors are connected to receive the detection photocurrent, and perform preamplification, analog-to-digital conversion and signal processing on the detection photocurrent to form a photoelectric feedback circuit to provide high stability constant current for the light source. The adjustable weak light generating device provided by the embodiment of the present invention enables the output port of the integrating sphere to have adjustable weak light with high stability through the adjustable aperture. The device is low in cost, high in precision and easy to operate.

Description

Adjustable faint light generator

technical field

The invention relates to the technical field of photodetector detection and calibration, in particular to an adjustable faint light generating device.

Background technique

Photodetector detection and calibration technology is a new detection technology produced by the combination of optics and electronics. It includes two main aspects, the first is the measurement of light source intensity, that is, the detection of optical radiation source; the second is the detection of photodetector detection responsivity, linearity and other characteristics. Weak light detection technology is a low-range category in the field of optical radiation and photodetector detection and calibration technology, so it also includes the above two aspects: light source and light detector. The existing weak light detection technology usually converts the optical signal into an electrical signal through a high-sensitivity photoelectric device, and then amplifies it through a preamplifier circuit, and then converts the analog signal into a digital signal by the A/D conversion circuit for analysis and processing. This technology can be used to detect the intensity of various weak light sources, the responsivity (quantum efficiency) of high-sensitivity detectors, the photon counting of light detection instruments or the linearity of detection signals.

In the field of chemical analysis, biochemical analysis instruments based on the principle of luminescence detection involve weak light detection technology. The traditional method is to use expensive standard substances to generate fluorescence to calibrate chemical testing instruments. The problems of this method include : The cost of preparation, storage and use of the chemical consumables involved is very high; due to the uncertainty of the purity of the standard substance and the use of environmental factors, the repeatability of instrument measurement and calibration cannot be further improved; the detection process is complicated, and long-term use will lead to detection The detection accuracy of the device is reduced; this method can only configure a limited number of fluorescence intensities, and cannot achieve continuous adjustment of the fluorescence intensity with a large dynamic range when testing and calibrating the instrument. Therefore, the traditional weak light detection instrument calibration technology based on chemical fluorescence still needs to overcome these shortcomings and continue to develop and improve.

Contents of the invention

The purpose of the present invention is to provide an adjustable weak light generating device, which can be directly applied in the field of calibration and detection of weak light detection equipment, especially in the field of calibration and detection of biochemical analysis instruments based on the principle of weak light detection, and has the ability to reduce the use of consumables for detection and calibration. The advantages of low cost, shortened detection time, and improved repeatability of device calibration avoid the cumbersome process of configuring the standard substance solution concentration-reactive luminescence method and the problem of luminescence differences caused by the standard substance concentration and ambient temperature. At the same time, the adjustable weak light generating device provided by the present invention can realize the characteristics that the detection device has a large dynamic range, can be continuously adjusted and can display the intensity of the light source in real time, so that multi-point high The linear inspection of the density can then obtain the linearity and nonlinear range of the instrument under test, and even perform numerical correction in the nonlinear area to expand the dynamic range of the instrument under test.

In order to achieve the above purpose, the present invention provides an adjustable weak light generating device, comprising:

a light source for outputting incident light;

An adjustable aperture is arranged at the exit end of the light source, and the luminous flux of the incident light passing through the adjustable aperture is controlled by adjusting the opening area of the adjustable aperture;

Integrating sphere, including entrance, exit, screen and photodetector;

The incident port is set corresponding to the light exit end of the adjustable aperture, and receives the adjusted incident light passing through the adjustable aperture; the inner wall of the integrating sphere has a reflective coating, and the reflection wavelength range is from 300nm to 2500nm, the reflectivity is 95%-100%;

The screen is arranged perpendicular to the line between the entrance and the exit, and reflects the adjusted incident light; the reflected light formed by the reflection is reflected multiple times by the inner wall of the integrating sphere After that, it is received by the photodetector and emitted from the exit port;

The photodetector performs photoelectric conversion on the received reflected light, and outputs a detection photocurrent;

A programmable photometer, connected to the photodetector, receives the detection photocurrent, performs pre-amplification, analog-to-digital conversion and signal processing on the detection photocurrent to form a photoelectric feedback circuit, thereby according to the photoelectric feedback The circuit displays in real time the intensity of the adjustable weak light output by the exit port of the integrating sphere.

Preferably, the integrating sphere includes a first hemisphere and a second hemisphere;

The first hemisphere and the second hemisphere are bonded and fixed by the ball joint flange, so that the integrating sphere forms a closed structure;

Further preferably, the screen shield includes: a screen shield body and a fixed end.

The fixed end is extended from the shield body; the diameter of the shield body is smaller than the inner diameter of the integrating sphere;

There is a protruding structure on the side wall of the first hemisphere or the second hemisphere, and a connection hole is provided on the fixed end, which is sleeved on the protruding structure; when the first hemisphere and the second hemisphere are buckled When combined into a closed structure, the screen is fixed inside the integrating sphere through the fixed end.

Preferably, the adjustable aperture includes: an aperture and an adjustment device;

The adjusting device includes an adjusting knob, a spring, an adjusting rod and a slide rail;

The rotation of the adjustment knob drives the spring to compress or stretch, so that the adjustment rod moves up and down along the slide rail in a direction perpendicular to the incident light, thereby changing the aperture of the diaphragm.

Further preferably, the sidewall of the diaphragm has an oxide coating.

Preferably, the light source specifically includes: a planar cold light source, an optical filter and a heat sink;

The planar cold light source is connected to the photoelectric feedback circuit, and outputs the first light source according to the power supply signal provided by the photoelectric feedback circuit;

The optical filter is arranged at the output end of the planar cold light source, filters the first light source, and outputs the incident light;

The heat sink is sleeved outside the planar cold light source to dissipate heat from the planar cold light source.

Preferably, the adjustable weak light generating device also includes a supporting base;

There are at least two supporting bases, which are respectively arranged at the bottom of the integrating sphere and the light source; the bases are connected to the placement plane of the adjustable weak light generating device through the bases.

Preferably, the programmable photometer includes the photoelectric feedback circuit, storage circuit and interface circuit;

Wherein, the photoelectric feedback circuit includes:

a weak current amplification circuit, receiving the detection photocurrent output by the photodetector, and performing signal amplification processing on the detection photocurrent;

An analog-to-digital conversion circuit, connected to the output terminal of the weak current amplification circuit, performs analog-to-digital conversion processing on the detection photocurrent voltage signal after the signal amplification processing, and outputs a digital signal;

A micro control unit, connected to the analog-to-digital conversion circuit, the storage circuit and the interface circuit, processes the digital signal of the analog-to-digital conversion circuit, and outputs a digital voltage control signal to the storage circuit and the interface circuit;

A numerical control constant current source is connected to the micro control unit, and outputs a controllable constant current power supply signal according to the digital voltage control signal output by the micro control unit;

The range switching circuit is connected with the micro control unit, performs automatic range switching control according to the digital voltage control signal output by the micro control unit, and generates a control signal to feedback control the weak current amplifying circuit.

Preferably, the programmable photometer further includes: a dot-matrix liquid crystal display and a keyboard.

The adjustable weak light generating device provided by the present invention controls the planar cold light source through the photoelectric feedback circuit in the programmable photometer to make it emit incident light with controllable light intensity, and the incident light is reflected by the photoelectric detector through the reflection in the integrating sphere Receiving, the photodetector will feed back the detection photocurrent to the photoelectric feedback circuit in the programmable photometer to form a loop feedback, and realize the detection device has the characteristics of continuous adjustment with a large dynamic range and real-time display of the light source intensity, so that the weak Optical measuring instruments or photon counting test instruments carry out multi-point high-density linear inspection, and then can obtain the linearity and nonlinear range of the tested instrument, and even perform numerical correction in the nonlinear region to expand the dynamic range of the tested instrument. The adjustable faint light generating device provided by the embodiments of the present invention has low cost, high precision and easy operation.

Description of drawings

Figure 1 is a cross-sectional view of an adjustable weak light generating device provided by an embodiment of the present invention;

Fig. 2 is a perspective view of an adjustable weak light generating device provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram of the shield screen of the adjustable weak light generating device provided by the embodiment of the present invention;

Fig. 4 is a schematic diagram of the programmable photometer of the adjustable weak light generating device provided by the embodiment of the present invention.

detailed description

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Fig. 1 is a cross-sectional view of the adjustable weak light generating device of the present invention, and Fig. 2 is a perspective view of the adjustable weak light generating device of the present invention, as shown in Fig. 1 and Fig. 2, the adjustable weak light generating device of the present invention includes: a light source 1. Adjustable diaphragm 2, integrating sphere 3 and programmable photometer 4.

As shown in FIG. 1 , the light source 1 specifically includes a planar cold light source 11 , an optical filter 12 and a heat sink 13 .

Wherein, the planar cold light source 11 is connected with the photoelectric feedback circuit 40 in the programmable photometer 4, and the controllable constant current power supply signal provided by the photoelectric feedback circuit 40 is used as the power supply input of the planar cold light source 11 to realize the high stability of the planar cold light source degree of light output.

The optical filter 12 is arranged at the output end of the planar cold light source 11 , and the incident light is output after being filtered by the optical filter 12 . Because the adjustable weak light generating device proposed by the present invention aims to use the weak light source generated by the device to replace the weak fluorescence produced by the chemical reaction of the standard substance, and to calibrate the chemical fluorescence tester. The color of the emitted light from the light source of the device should be as consistent as possible with the fluorescent color produced by the chemical reaction. Therefore, by installing an optical filter at the exit end of the planar cold light source, the color of the light from the planar cold light source is changed after passing through the optical filter, and its color is close to that of chemical fluorescence. The measurement error of the instrument is caused by the difference in the responsivity of the internal detector.

The radiator 13 is socketed outside the planar cold light source 11 to cool the planar cold light source 11, prolong the service life of the light source, and reduce detection errors caused by temperature changes.

Preferably, the illuminance range of the weak light output by the light source 1 is (10- ¹³ -10- ⁸ ) lx.

The adjustable aperture 2 is arranged at the output end of the light source 1 , and the adjustable aperture 2 has an aperture 21 and an adjusting device 22 .

Specifically, the adjusting device 22 includes an adjusting knob 221, a spring (not shown in the figure), an adjusting rod 222 and a slide rail (not shown in the figure). When the adjustment knob 221 rotates, the adjustment knob 221 drives the adjustment rod 222 to move, so that the spring (not shown in the figure) is compressed or stretched, so that the adjustment rod 222 moves up and down along the slide rail and in the direction perpendicular to the incident light, thereby changing The aperture of the diaphragm 21 thereby changes the magnitude of the luminous flux of the input light. By adjusting the diaphragm 21 in this way, the smoothness of adjustment of the diaphragm 21 can be improved, and the phenomenon of being stuck or unable to return can be avoided. In addition, in order to prevent the diaphragm 21 from affecting the luminous flux of the input light due to reflection phenomenon, the sidewall of the diaphragm 21 is oxidized, preferably oxidized to black.

The integrating sphere 3 has an entrance 31 , an exit 32 , a screen 33 and a photodetector 34 .

The entrance 31 of the integrating sphere 3 is set corresponding to the light exit end of the adjustable diaphragm 2 , and the connecting line between the entrance 31 and the exit 32 is parallel to the incident light. The adjusted incident light passing through the adjustable diaphragm 2 can be received through the incident port 31 . The shield screen 33 is arranged vertically to the connection line between the entrance 31 and the exit opening 32, and reflects the incident light entering the integrating sphere 3. Port 32 emits and is received by photodetector 34 .

More specifically, as shown in FIG. 3 , the screen shield 33 includes a screen shield body 331 , a fixed end 332 and a connection hole 333 . The fixed end 332 extends from the shield body 331 , and its length is greater than the inner diameter of the integrating sphere 3 . The shield body 331 is preferably circular or approximately circular, and its diameter is smaller than the inner diameter of the integrating sphere 3 .

As shown in FIGS. 1-3 , the specific structure of the integrating sphere 3 includes a first hemisphere 35 and a second hemisphere 36 .

The first hemisphere 35 and the second hemisphere 36 are fitted and fixed by the ball joint flange, so that the integrating sphere 3 forms a closed structure. There is a protruding structure on the side wall of the first hemisphere 35 or the second hemisphere 36, and there is a groove structure on the side wall of the other hemisphere correspondingly. From the structure. When the first hemisphere 35 is engaged with the second hemisphere 36 to form a closed structure, the shield screen 331 is fixed inside the integrating sphere 3 through the fixed end 332 .

In addition, in order to improve the reflectivity of incident light, the inner wall of the integrating sphere 3 has a reflective coating. Specifically, the actual thickness of the coating is preferably about 3mm, the reflection wavelength range is from 300nm to 2500nm, and the reflectivity is not lower than 95%.

As shown in Fig. 1 again, the programmable photometer 4 is electrically connected with the photodetector 34 in the integrating sphere 3, receives the first detection photocurrent, by carrying out preamplification, analog-to-digital conversion and signal processing to the first detection photocurrent , form a photoelectric feedback circuit 40, and output a controllable constant current power supply signal. After the light source 1 is powered by the photoelectric feedback circuit 40, the adjustable diaphragm 2 is adjusted, and the adjustable weak light is output at the outlet of the integrating sphere 3. At the same time, the signal strength of the controllable constant current power supply is processed by the photoelectric feedback circuit 40 and displayed in real time. on other devices.

Fig. 4 is a schematic diagram of the programmable photometer of the adjustable faint light generating device of the present invention. As shown in FIGS. 1-4 , the programmable photometer 4 includes a photoelectric feedback circuit 40 , a storage circuit 46 and an interface circuit 47 . The photoelectric feedback circuit 40 specifically includes: a weak current amplification circuit 41 , an analog-to-digital conversion circuit 42 , a range switching circuit 43 , a micro control unit 44 and a digitally controlled constant current source 45 . The programmable photometer 4 in this embodiment can be understood as an observable instrument, which is a device capable of inputting and outputting data and having a processing function.

Wherein, the micro control unit 44 carries out two major independent controls:

The first part is to collect signals from the photodetector 34 by controlling the weak current amplification circuit 41 and the digital-to-analog conversion circuit 42 . If the collected value sent by the digital-to-analog conversion circuit 42 to the micro-control unit 44 is not within the current range, the micro-control unit 44 will control the range switching circuit 43 through a digital voltage control signal to switch the weak current amplifier circuit 41 to an appropriate range. After the range is appropriate, the micro-control unit 44 displays the light source intensity data after switching the range through the dot-matrix liquid crystal display 48 . In addition, some calibration information can be input to the micro-control unit 44 through the keyboard 48, and the memory circuit 46 can also be controlled by the micro-control unit 44 to write in the read-only memory, so as to realize permanent storage of digital information.

The second part is that the micro-control unit 44 controls to change the reference voltage of some circuits of the numerical control constant current source 45, so as to realize the digital control of the current output of the numerical control constant current source 45.

All control signals of the micro-control unit 44 are voltage-type signals. Preferably, the micro-control unit 44 operates through a serial peripheral interface (Serial Peripheral Interface, SPI) bus.

Specifically, because the current generated by the weak light is extremely small, the weak current amplifier circuit 41 uses a wide range and high sensitivity weak current amplifier circuit. This weak current amplifier circuit receives the first detection photocurrent output by the photodetector 34 and detects The photocurrent performs signal amplification processing; the analog-to-digital conversion circuit 42 is used to digitize the amplified detection photocurrent, and output the first digital signal, and the converted first digital signal is digitally processed for the first time by the micro control unit 44. deal with. The data after the above-mentioned first digital processing will be fed back to the range switching circuit 43 at the same time. After the range switching circuit 43 automatically switches the range according to the digital voltage control signal output by the micro control unit 44, the second detection photocurrent is formed. The detection photocurrent is again subjected to current amplification and analog-to-digital conversion in sequence, thereby forming a detection photocurrent cycle. The above cycle process can be repeated many times.

At the same time, the micro control unit 44 will also send the detection result of this photocurrent detection cycle to the interface circuit 47 . The interface circuit 47 can perform data communication with a computer or other host computer through the instruction protocol of the program firmware of the micro-control unit 44, so that the tester can save the test results.

As shown in Fig. 1 again, the bottom of integrating sphere 3 and light source 1 has support base 5, comprises two support bases 51,52 at least in specific implementation, is respectively arranged on integrating sphere 3 below and radiator 13 below, and support base 51 , 52 are connected with the placement plane of the entire adjustable weak light generating device, and support the entire adjustable weak light generating device so that it is higher than the placement surface of the adjustable weak light generating device, thereby playing the roles of balance, heat dissipation, and shockproof.

When using an adjustable dim light generator:

First, the photoelectric feedback circuit 40 generates a first current to the planar cold light source 11 to generate a first light source signal, and the first light source signal is filtered by the optical filter 12 to form incident light.

The incident light filtered by the optical filter 12 passes through the diaphragm 2 to adjust the luminous flux, and enters the integrating sphere 3 from the entrance 31 . The input light is reflected multiple times by the inner wall of the integrating sphere 3 and the screen 33 , and then is received by the photodetector 34 , and is emitted to the test instrument through the output port 32 .

The photosensitive part in the photodetector 34 generates the first detection photocurrent, and the first detection photocurrent enters the analog-to-digital conversion circuit 42 after being amplified by the weak current amplifier circuit 41, generates the first digital signal, and transmits the first digital signal to the microcontroller unit 44.

The micro-control unit 44 determines whether the current detected photocurrent value is within the current range according to the first digital signal, and if so, converts it into a first digital voltage control signal and sends it to the storage circuit 46 and the interface circuit 47 for personalization programming and communication. If it is determined that it is not within the current range, then output a range switching control signal according to the first digital signal and the range setting parameter and send it to the range switching circuit 43 for range switching processing by the weak current amplification circuit 41 . After processing, the first control signal is output and fed back to the weak current amplifier circuit 41 to form a feedback loop for detecting the photocurrent for the first time, and then enters the micro control unit 44 through the analog-to-digital conversion circuit 42 . In the case of being in the measuring range, the micro-control unit 44 outputs the first digital voltage control signal, and sends it to the dot-matrix liquid crystal display 48 and the interface circuit 47 for personalized display and communication; or directly uses the storage circuit 46 and the interface circuit 47 The external program in the program returns the programmed digital voltage control signal to the micro control unit 44 to form a second digital voltage control signal.

Finally, the numerical control constant current source 45 receives the digital voltage control signal programmed by the micro control unit 44 to generate a controllable constant current power supply signal. By adjusting the differential mechanical adjustment knob 221 of the adjustable aperture 2, a faint light from weak to strong is generated at the exit port 32, and at the same time, the signal strength of the controllable constant current power supply is processed by the photoelectric feedback circuit 40 and displayed on the dot-matrix liquid crystal display in real time 48 or interface circuit 47. By adjusting the weak light intensity of the exit port 32 to generate different detection data, the tester can calibrate the test instrument after comparing the different detection data.

The adjustable weak light generating device provided by the embodiments of the present invention can replace the method of using expensive standard substances to generate fluorescence to calibrate the test instrument. It has the advantages of reducing the cost of consumables used for detection and calibration, shortening the detection time and improving the repeatability of device calibration, avoiding the cumbersome process of configuring the standard substance solution concentration reaction luminescence method and the problem of luminescence differences caused by standard substance concentration and ambient temperature . Moreover, the design of the programmable photometer well solves the problem of single, unsustainable and non-dynamic display of weak light detection results. The detection device has the characteristics of continuously adjustable large dynamic range and real-time display of light source intensity, so that multi-point high-density linear inspection of the calibrated weak light measuring instrument or photon counting test instrument can be carried out, and the measured instrument can be obtained. Linearity and non-linear range, even numerical correction can be performed in the non-linear region to expand the dynamic range of the instrument under test.

Professionals should further realize that the units and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the relationship between hardware and software Interchangeability. In the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

The steps of the methods or algorithms described in connection with the embodiments disclosed herein may be implemented by hardware, software modules executed by a processor, or a combination of both. Software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other Any other known storage medium.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (9)

1. a kind of adjustable faint light generating apparatus, it is characterised in that the adjustable faint light generating apparatus include：

Light source, for exporting incident light；

Adjustable diaphragm, is arranged at the exit end of the light source, and by adjusting the aperture area of the adjustable diaphragm, control passes through can Dim the luminous flux of the incident light of door screen；

Integrating sphere, including entrance port, exit portal, shelves screen and photodetector；

The light exit side that the entrance port corresponds to the adjustable diaphragm is set, and receives by after the adjustment of the adjustable diaphragm Incident light；The inwall of the integrating sphere has reflectance coating, and reflected wavelength range is 300nm to 2500nm, and reflectivity is 95%- 100%；

Line of the shelves screen between the entrance port and the exit portal is set, and the incident light after the adjustment is entered Row reflection；The reflected light for reflecting to form by the photodetector by after the multiple reflections of the integrating sphere inwall, being connect Receive, and projected by exit portal；

The photodetector carries out opto-electronic conversion, output detection photoelectric current to the reflected light for receiving；

Programmable photometer, is connected with the photodetector, receives the detection photoelectric current, and the detection photoelectricity is flowed into The preposition amplification of row, analog-to-digital conversion and signal transacting, form electro-optical feedback circuit, so as to be shown in real time according to the electro-optical feedback circuit Show that the exit portal of the integrating sphere exports the intensity of the adjustable faint light.

2. adjustable faint light generating apparatus according to claim 1, it is characterised in that the integrating sphere includes the first hemisphere With the second hemisphere；

First hemisphere and second hemisphere are fitted by ball abutted flange and fixed so that the integrating sphere forms closure knot Structure.

3. adjustable faint light generating apparatus according to claim 2, it is characterised in that the shelves screen includes：Shelves screen body And fixing end；

The fixing end is extended by the shelves screen body；Internal diameter of the diameter of the shelves screen body less than the integrating sphere；

There is bulge-structure on the side wall of first hemisphere or the second hemisphere, there is connecting hole in the fixing end, be socketed on On the bulge-structure；When first hemisphere is fastened as closing structure with second hemisphere, the shelves screen is by described Fixing end is fixed on inside the integrating sphere.

4. adjustable faint light generating apparatus according to claim 1, it is characterised in that the adjustable diaphragm includes：Diaphragm And adjusting means；

The adjusting means includes adjusting knob, spring, adjusting rod and slide rail；

The adjusting knob is rotated and drives the spring-compressed or stretching so that the adjusting rod is along the slide rail in vertical incidence The direction of light moves up and down, so as to change the aperture of the diaphragm.

5. adjustable faint light generating apparatus according to claim 4, it is characterised in that the side wall of the diaphragm has oxidation Coating.

6. adjustable faint light generating apparatus according to claim 1, it is characterised in that the light source is specifically included：Plane Cold light source, optical filter and radiator；

The plane cold light source is connected with the electro-optical feedback circuit, according to the power supply signal that the electro-optical feedback circuit is provided Export the first light source；

The optical filter is arranged at the output end of the plane cold light source, and optical filtering treatment is carried out to first light source, defeated Go out the incident light；

The radiator muff-joint is connected to outside the plane cold light source, and the plane cold light source is radiated.

7. adjustable faint light generating apparatus according to claim 1, it is characterised in that the adjustable faint light generating apparatus Also include support base；

The support base at least two, is respectively arranged at the bottom of the integrating sphere and the light source；By the base Holding plane with the adjustable faint light generating apparatus connects.

8. adjustable faint light generating apparatus according to claim 1, it is characterised in that the programmable photometer includes institute State electro-optical feedback circuit, storage circuit and interface circuit；

Wherein, the electro-optical feedback circuit includes：

Weak current amplifying circuit, receives the detection photoelectric current of the photodetector output, to the detection photoelectric current Carry out signal enhanced processing；

Analog to digital conversion circuit, is connected with the weak current amplification circuit output end, to the detection after the signal enhanced processing Photocurrent-voltage signal carries out analog-to-digital conversion process, output digit signals；

Micro-control unit, is connected with analog-digital conversion circuit as described, storage circuit and the interface circuit, to analog-to-digital conversion electricity The data signal on road is processed, output digital voltage control signal to the storage circuit and the interface circuit；

Digital-control constant-flow source, is connected with the micro-control unit, and the digital voltage exported according to the micro-control unit controls letter Number, export controllable constant-current power supply signal；

Range switch circuit, is connected with the micro-control unit, according to the digital voltage that the micro-control unit is exported Control signal carries out automatic range switching control, weak current amplifying circuit described in generation control signal feedback control.

9. adjustable faint light generating apparatus according to claim 8, it is characterised in that the programmable photometer is also wrapped Include：Lattice lcd display and keyboard.