阅读说明：本技术 一种led脉冲激发光源系统 (LED pulse excitation light source system ) 是由 杨鹏 吴国俊 王东升 宋矫健 吕小鹏 于 2019-09-10 设计创作，主要内容包括：本发明公开一种LED脉冲激发光源系统,包括：通过上位机设定LED脉冲激发光源光功率值；控制模块对LED脉冲激发光源光功率值进行映射处理,得到参考电压信号值；LED驱动模块驱动光源模块发光并通过参考电压信号值调节使光源模块发光所需的电流；光源模块发光并输出特定波段的LED脉冲激发光源；光功率采集模块实时采集LED脉冲激发光源耦合光功率值；控制模块根据LED脉冲激发光源耦合光功率值,闭环反馈修正参考电压信号值。本发明通过输出特定波段的LED脉冲激发光源以及闭环反馈修正参考电压信号值,实现LED脉冲激发光源光功率的稳定,避免了LED脉冲激发光源受时间以及温度等环境因素造成的光功率和峰值波长漂移,提高了水下荧光类传感器的灵敏度和稳定性。(The invention discloses an LED pulse excitation light source system, which comprises: setting the light power value of the LED pulse excitation light source through an upper computer; the control module maps the light power value of the LED pulse excitation light source to obtain a reference voltage signal value; the LED driving module drives the light source module to emit light and adjusts the current required by the light source module to emit light through the reference voltage signal value; the light source module emits light and outputs an LED pulse excitation light source with a specific wave band; the optical power acquisition module acquires the coupling optical power value of the LED pulse excitation light source in real time; and the control module performs closed-loop feedback correction on the reference voltage signal value according to the light power value coupled by the LED pulse excitation light source. According to the invention, the stability of the light power of the LED pulse excitation light source is realized by outputting the LED pulse excitation light source with a specific waveband and performing closed-loop feedback correction on the reference voltage signal value, the light power and peak wavelength drift of the LED pulse excitation light source caused by environmental factors such as time, temperature and the like are avoided, and the sensitivity and stability of the underwater fluorescent sensor are improved.)

1. An LED pulsed excitation light source system, comprising: the LED light source module comprises an upper computer, a control module, an LED driving module, a light source module and a light power acquisition module;

the control module is respectively connected with the upper computer, the LED driving module and the optical power acquisition module, the LED driving module is connected with the light source module, and the light source module is connected with the optical power acquisition module;

a user sets the light power value of the LED pulse excitation light source through the upper computer and sends the set light power value of the LED pulse excitation light source to the control module;

the control module maps the set light power value of the LED pulse excitation light source to obtain a reference voltage signal value, and the reference voltage signal value is sent to the LED driving module;

the LED driving module drives the light source module to emit light and adjusts the current required for driving the light source module to emit light through a reference voltage signal value;

the light source module emits light and outputs an LED pulse excitation light source with a specific wave band;

the light power acquisition module acquires the light power value of the coupling of the LED pulse excitation light source output by the light source module in real time and sends the acquired light power value of the coupling of the LED pulse excitation light source to the control module;

the control module comprises a PID control unit, the PID control unit calculates the light power value of the LED pulse excitation light source according to the received light power value coupled by the LED pulse excitation light source, and the reference voltage signal value is corrected through closed-loop feedback of the light power value of the LED pulse excitation light source, so that the light power of the LED pulse excitation light source is stable.

2. The LED pulse excitation light source system according to claim 1, wherein the LED driving module comprises a D/a conversion unit, a modulation unit, and a constant current source unit; the PID control unit is respectively connected with the D/A conversion unit and the modulation unit; the D/A conversion unit and the modulation unit are respectively connected with the constant current source unit.

3. The LED pulse excitation light source system according to claim 2, wherein the optical power collection module comprises a photoelectric sensor, an IV conversion unit, an A/D conversion unit; the photoelectric sensor is connected with the IV conversion unit; the IV conversion unit is connected with the A/D conversion unit; the A/D conversion unit is connected with the PID control unit.

4. The LED pulse excitation light source system according to claim 3, wherein the light source module comprises an LED, a narrow band pass filter; the LED is connected with the constant current source unit.

5. The LED pulse excitation light source system according to claim 4, wherein the number of the narrow band filters is two and the same, one of the narrow band filters is disposed at an emitting end of the LED, and the other narrow band filter is disposed at a photosensitive surface end of the photosensor.

6. The LED pulse excitation light source system according to claim 3, wherein the photosensor is configured to collect a current signal of a coupling light power value of the LED pulse excitation light source in a specific wavelength band.

7. The LED pulse excitation light source system according to claim 6, wherein the IV conversion unit is configured to convert a current signal for acquiring a value of the optical power coupled by the LED pulse excitation light source in a specific wavelength band into a voltage signal.

8. The LED pulse excitation light source system according to claim 1, wherein the closed-loop feedback correction reference voltage signal value specifically comprises:

s1: the light power acquisition module acquires the light power value of the LED pulse excitation light source coupling output by the light source module in real time and transmits the acquired light power value of the LED pulse excitation light source coupling to the PID control unit;

s2: the PID control unit calculates the light power value of the LED pulse excitation light source according to the received light power value coupled by the LED pulse excitation light source;

s3: comparing and calculating an absolute error value of the light power value of the LED pulse excitation light source obtained by the PID control unit and the light power value of the LED pulse excitation light source set by the upper computer;

s4: judging whether the absolute error value is larger than a preset threshold value, if so, correcting the reference voltage signal value by adopting a PID algorithm;

s5: and repeating S1-S4 until the final absolute error value is smaller than the preset threshold.

Technical Field

The invention relates to the technical field of underwater fluorescence detection, in particular to an LED pulse excitation light source system.

Background

At present, the ocean pollution is more serious, and the application of the underwater fluorescence sensor based on the fluorescence detection method in monitoring the water quality parameters such as chlorophyll alpha, oil in water, dissolved oxygen and the like is more extensive. In the fluorescence detection method, the fluorescence intensity is in positive correlation with the excitation light source intensity and is in direct proportion under specific conditions. An LED (Light Emitting Diode) is used as a commonly used excitation Light source for an underwater fluorescence sensor, and the intensity and peak wavelength of the excitation Light source determine the intensity and stability of a fluorescence signal, and directly affect the sensitivity and stability of the underwater fluorescence sensor.

The LED excitation light source of the traditional underwater fluorescence sensor is mainly driven by a constant current source, namely, the stability of the light power of the LED excitation light source is realized by ensuring the stability of pulse driving current. However, the luminous efficiency of the LED is attenuated with time, and under the influence of environmental factors such as temperature, the optical power and the peak wavelength of the LED excitation light source may drift, and the drift of the optical power and the peak wavelength may affect the sensitivity and the stability of the underwater fluorescent sensor. The open-loop constant current source driving scheme ignores the defects, and simultaneously cannot realize the linear adjustment of the intensity of the LED excitation light source due to the lack of real-time monitoring on the optical power of the LED excitation light source.

An LED excitation light source based on a constant current source is described in the document 'Circuit design of an in-situ seawater chlorophyll alpha sensor' (authors: Wuning, Wangzhaoyyu, Cao, and the like; published: instrument technology and sensor; published year: 2019, term: 1, start and stop page number: 9-11), but the scheme is designed into an open loop control system, does not consider the drift of LED optical power and peak wavelength caused by temperature and time, and limits the sensitivity and stability of an underwater fluorescence sensor. Patent No. CN 105244758A discloses a stable light source system for multi-wavelength semiconductor laser communication, in which a semiconductor stable light source based on a constant current source and temperature control is described, and a technical solution for performing constant temperature control on an LED to improve the stability of the optical power of the LED is provided. However, in the technical field of underwater fluorescence detection, the volume of a temperature control unit is large, a temperature sensor cannot accurately measure the temperature of a plurality of LEDs of different models without contact, the power consumption is high, the adjusting time is too long, the environmental adaptability is poor, the defects that the light power and the peak wavelength of an LED excitation light source drift along with time and the like cannot be eliminated, and the method is not suitable for the existing increasingly miniaturized underwater fluorescence detector.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an LED pulse excitation light source system.

The invention provides an LED pulse excitation light source system, which comprises: the LED light source module comprises an upper computer, a control module, an LED driving module, a light source module and a light power acquisition module;

the control module is respectively connected with the upper computer, the LED driving module and the optical power acquisition module, the LED driving module is connected with the light source module, and the light source module is connected with the optical power acquisition module;

a user sets the light power value of the LED pulse excitation light source through the upper computer and sends the set light power value of the LED pulse excitation light source to the control module;

the control module maps the set light power value of the LED pulse excitation light source to obtain a reference voltage signal value, and the reference voltage signal value is sent to the LED driving module;

the LED driving module drives the light source module to emit light and adjusts the current required for driving the light source module to emit light through a reference voltage signal value;

the light source module emits light and outputs an LED pulse excitation light source with a specific wave band;

the light power acquisition module acquires the light power value of the coupling of the LED pulse excitation light source output by the light source module in real time and sends the acquired light power value of the coupling of the LED pulse excitation light source to the control module;

the control module comprises a PID control unit, the PID control unit calculates the light power value of the LED pulse excitation light source according to the received light power value coupled by the LED pulse excitation light source, and the reference voltage signal value is corrected through closed-loop feedback of the light power value of the LED pulse excitation light source, so that the light power of the LED pulse excitation light source is stable.

Further, the LED driving module comprises a D/A conversion unit, a modulation unit and a constant current source unit; the PID control unit is respectively connected with the D/A conversion unit and the modulation unit; the D/A conversion unit and the modulation unit are respectively connected with the constant current source unit.

Further, the optical power acquisition module comprises a photoelectric sensor, an IV conversion unit and an A/D conversion unit; the photoelectric sensor is connected with the IV conversion unit; the IV conversion unit is connected with the A/D conversion unit; the A/D conversion unit is connected with the PID control unit.

Further, the light source module comprises an LED and a narrow-band filter; the LED is connected with the constant current source unit.

Furthermore, the number of the narrow-band filters is two and the same, one narrow-band filter is placed at the emergent light end of the LED, and the other narrow-band filter is placed at the photosensitive surface end of the photoelectric sensor.

Further, the photoelectric sensor is used for collecting a current signal of a light power value coupled by the LED pulse excitation light source of a specific waveband.

Further, the IV conversion unit is configured to convert a current signal, which is obtained by collecting a light power value coupled by the LED pulse excitation light source in a specific waveband, into a voltage signal.

Further, the closed-loop feedback correction reference voltage signal value specifically includes:

s1: the light power acquisition module acquires the light power value of the LED pulse excitation light source coupling output by the light source module in real time and transmits the acquired light power value of the LED pulse excitation light source coupling to the PID control unit;

s2: the PID control unit calculates the light power value of the LED pulse excitation light source according to the received light power value coupled by the LED pulse excitation light source;

s3: comparing and calculating an absolute error value of the light power value of the LED pulse excitation light source obtained by the PID control unit and the light power value of the LED pulse excitation light source set by the upper computer;

s4: judging whether the absolute error value is larger than a preset threshold value, if so, correcting the reference voltage signal value by adopting a PID algorithm;

s5: and repeating S1-S4 until the final absolute error value is smaller than the preset threshold.

The invention has the technical effects or advantages that:

(1) according to the invention, the LED is used as an excitation light source device, the same narrow-band optical filters are arranged at the emergent light end of the LED and the photosensitive surface end of the photoelectric sensor, the LED pulse excitation light source with a specific waveband can be ensured to be output, the peak wavelength drift caused by the influence of factors such as time and temperature is avoided, and the sensitivity and stability of the underwater fluorescent sensor are improved.

(2) According to the invention, the photoelectric sensor is used for collecting the current signal of the LED pulse excitation light source coupling light power value of the specific wave band in real time, the LED pulse excitation light source light power value of the specific wave band is obtained through calculation, the reference voltage signal value is corrected through the PID control unit closed-loop feedback, the stability of the LED pulse excitation light source light power is realized, the light power drift caused by the influence of factors such as time and temperature is avoided, and the sensitivity and the stability of the underwater fluorescence sensor are improved.

Drawings

FIG. 1 is a schematic diagram of an LED pulsed excitation light source system according to an embodiment of the invention;

fig. 2 is a schematic structural diagram of an LED pulse excitation light source system according to another embodiment of the invention.

Fig. 3 is a flow chart of closed-loop control of LED pulsed excitation light source optical power stabilization according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and the detailed description.

Fig. 1 is a schematic structural diagram of an LED pulse excitation light source system according to an embodiment of the invention.

As shown in fig. 1, the LED pulse excitation light source system of the present invention includes an upper computer, a control module, an LED driving module, and an optical power collecting module. The control module is respectively connected with the upper computer, the LED driving module and the light power acquisition module, the LED driving module is connected with the light source module, and the light source module is connected with the light power acquisition module.

Specifically, a user sets a target LED pulse excitation light source light power value through an upper computer and sends the set target LED pulse excitation light source light power value to a control module; the control module receives a target LED pulse excitation light source light power value sent by the upper computer and carries out mapping processing to obtain a reference voltage signal value; the mapping process is as follows: the control module stores mapping data of the light power value of the LED pulse excitation light source and the reference voltage signal value, and performs mapping processing on the set target light power value of the LED pulse excitation light source to obtain a corresponding reference voltage signal value. Sending the reference voltage signal value to an LED driving module, wherein the LED driving module drives a light source module to emit light, and adjusting the current required for driving the light source module to emit light according to the reference voltage signal value; through the driving of the LED driving module and the current input, the light source module emits light and outputs an LED pulse excitation light source with a specific wave band; then, the light power acquisition module acquires the light power value of the coupling of the LED pulse excitation light source output by the light source module in real time and transmits the acquired light power value of the coupling of the LED pulse excitation light source to the control module; the control module comprises a PID control unit, the PID control unit calculates the light power value of the LED pulse excitation light source according to the received light power value coupled by the LED pulse excitation light source, and the reference voltage signal value is corrected through closed-loop feedback of the light power value of the LED pulse excitation light source, so that the light power of the LED pulse excitation light source is stable.

In the embodiment, the light power value of the LED pulse excitation light source in the specific waveband is collected, the reference voltage signal value is corrected by adopting the closed-loop feedback of the PID control unit, the stability of the light power of the LED pulse excitation light source is realized, the drift of the peak wavelength and the light power caused by the influence of factors such as time, temperature and the like is avoided, and the sensitivity and the stability of the underwater fluorescent sensor are improved.

Fig. 2 is a schematic structural diagram of an LED pulse excitation light source system according to another embodiment of the invention. The LED pulse excitation light source system of this embodiment further describes specific structures of the control module, the LED driving module, the light source module and the optical power collecting module on the basis of the structure of the embodiment shown in fig. 1.

Wherein:

the available PC of host computer (personal computer), also can be with touch-sensitive screen etc. the host computer communicates through USB commentaries on classics serial unit with control module, and USB commentaries on classics serial unit adopts CH 340N. The control module comprises a PID (proportional, integral, derivative) control unit. The LED driving module comprises a D/A conversion unit (a digital-to-analog conversion unit for converting digital quantity into analog quantity), a modulation unit and a constant current source unit. The optical power acquisition module comprises a photoelectric sensor, an IV conversion unit (a current-voltage conversion unit) and an A/D conversion unit (an analog-to-digital conversion unit for converting analog quantity into digital quantity). The light source module comprises an LED and a narrow-band filter.

In the device, the upper computer is bidirectionally connected with the USB-to-serial port unit, and the USB-to-serial port unit is bidirectionally connected with the PID control unit; the PID control unit is respectively connected with the modulation unit, the D/A conversion unit and the A/D conversion unit, the modulation unit and the D/A conversion unit are respectively connected with the constant current source unit, and the constant current source unit is connected with the LED; the photoelectric sensor is connected with the IV conversion unit, the IV conversion unit is connected with the A/D conversion unit, and the A/D conversion unit is connected with the PID control unit.

Furthermore, narrow-band filters are arranged at the emergent light end of the LED and the photosensitive surface end of the photoelectric sensor, and the narrow-band filters which are the same as the emergent light end of the LED are arranged at the photosensitive surface end of the photoelectric sensor and can be used for outputting an LED pulse excitation light source with a specific waveband.

The specific working principle of this embodiment is as follows: a user sets a target LED pulse excitation light source light power value through an upper computer, the set target LED pulse excitation light source light power value is sent to a PID control unit through a USB-to-serial port unit, the PID control unit receives the target LED pulse excitation light source light power value sent by the upper computer, the target LED pulse excitation light source light power value is subjected to mapping processing according to mapping data of the LED pulse excitation light source light power value and a reference voltage signal value stored in the PID control unit, and the target LED pulse excitation light source light power value is converted into a 16-bit digital quantity value, so that a reference voltage signal value of corresponding digital quantity is obtained. The digital reference voltage signal value is sent to the D/a conversion unit through an SPI (Serial Peripheral Interface) communication bus, and the D/a conversion unit converts the digital value sent by the PID control unit into an analog value and outputs the analog reference voltage signal value. The PID control unit controls the modulation unit to enable the pulse signal to drive the LED to emit light, the constant current source unit is used for outputting current required by driving the LED to emit light, and the constant current output by the constant current source unit is adjusted through the reference voltage signal value of the analog quantity. The same narrow-band filters are arranged at the emergent light end of the LED and the photosensitive surface end of the photoelectric sensor, and the LED pulse excitation light source with a specific waveband can be output through the driving of an enabling signal, the constant current input and the action of the narrow-band filters. The photosensitive surface of the photoelectric sensor faces the side face or the back face of the LED, so that the photoelectric sensor can acquire the coupling light power value of the LED pulse excitation light source with a specific waveband in the lateral direction or the back direction, the coupling light power value of the LED pulse excitation light source and the light power value of the LED pulse excitation light source are in a proportional relation, and the coupling light power value of the LED pulse excitation light source is multiplied by a corresponding proportional coefficient to calculate the light power value of the LED pulse excitation light source. The photoelectric sensor collects current signals of the coupling light power value of the light-emitting state and the light-out state of the LED pulse excitation light source in real time, wherein the current signals of the coupling light power value of the light-out state of the LED pulse excitation light source only contain background noise such as dark current, the current signals of the coupling light power value of the light-emitting state and the light-out state of the LED pulse excitation light source collected by the photoelectric sensor are processed by the IV conversion unit to respectively obtain high and low level numerical values of the voltage signals of the coupling light power value, and the high level numerical values contain the voltage signals of the coupling light power value of the light-emitting state of the LED pulse excitation light source and the background noise such as dark current after being processed by the A/D conversion; the low level value only includes background noise such as dark current in the off state of the LED pulse excitation light source. The method comprises the steps of sending high and low level numerical values of coupled optical power to a PID control unit, obtaining a coupling optical power value of an LED pulse excitation light source in a specific waveband by the PID control unit after the high and low level numerical values of the coupled optical power are differentiated, obtaining an optical power value of the LED pulse excitation light source after the coupling optical power value is multiplied by a corresponding proportionality coefficient, comparing the obtained optical power value of the LED pulse excitation light source with an optical power value of a target LED pulse excitation light source set by an upper computer, and correcting a reference voltage signal value through closed-loop feedback to realize the stability of the optical power of the LED pulse excitation light source.

In the embodiment, an LED is used as an excitation light source device, and the same narrow-band optical filters are arranged at the emergent light end of the LED and the photosensitive surface end of the photoelectric sensor, so that the LED pulse excitation light source with a specific waveband can be ensured to be output; the photoelectric sensor is used for collecting current signals of the LED pulse excitation light source coupling light power of the specific wave band in real time, the light power value of the LED pulse excitation light source of the specific wave band is obtained through calculation, and the reference voltage signal value is corrected through the PID control unit in closed-loop feedback, so that the stability of the light power of the LED pulse excitation light source is realized. The drifting of the peak wavelength and the optical power caused by the influence of factors such as time, temperature and the like is avoided, and the sensitivity and the stability of the underwater fluorescent sensor are improved.

FIG. 3 is a flow chart of closed-loop control of LED pulse excitation for stabilizing the light power of the light source according to one embodiment of the present invention. The closed-loop control of the present embodiment is explained below with reference to fig. 3. As shown in fig. 3, the closed-loop control provided by this embodiment mainly includes the following steps:

s1: the light power acquisition module acquires the light power value of the LED pulse excitation light source coupling output by the light source module in real time and transmits the acquired light power value of the LED pulse excitation light source coupling to the PID control unit;

s2: the PID control unit calculates the light power value of the LED pulse excitation light source according to the received light power value coupled by the LED pulse excitation light source;

s3: comparing and calculating an absolute error value of the light power value of the LED pulse excitation light source obtained by the PID control unit and the light power value of the LED pulse excitation light source set by the upper computer;

s4: judging whether the absolute error value is larger than a preset threshold value, if so, correcting the reference voltage signal value by adopting a PID algorithm;

s5: and repeating S1-S4 until the final absolute error value is smaller than the preset threshold.

In the embodiment, the light power value of the LED pulse excitation light source coupled with the specific waveband is collected, and the reference voltage signal value is corrected by adopting the PID control unit to perform closed-loop feedback, so that the stability of the light power of the LED pulse excitation light source is realized, the drift of the peak wavelength and the light power caused by the influence of factors such as time, temperature and the like is avoided, and the sensitivity and the stability of the underwater fluorescent sensor are improved.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.