CN203979949U - Light intensity and the controlled LED light source system of flicker frequency in Optical Electro-Chemistry measurement - Google Patents

Abstract

The utility model relates to an LED light source system with controllable light intensity and flicker frequency in photoelectrochemical measurement. The instruments used for light intensity modulation photocurrent spectroscopy rely on self-owned equipment, lacking targeted integrated LED light source equipment. The utility model includes a background light source, a background light drive module, a modulation light source, a modulation light drive module, a function switching switch and an interface; the background light drive module sequentially includes a multivibrator, a counter 74LS161, a multi-way switching switch, and an OR gate chip 74LS321/ 4 and LED constant current driver PT4115; the modulated light drive module includes an optocoupler relay and an adding circuit in turn, and the core of the adding circuit is a power amplifier. The utility model has high light source intensity, stable brightness and good thermal stability, can effectively meet the measurement requirements of controllable light intensity and flicker frequency, has strong pertinence and high integration, and can directly realize the measurement of photocurrent-time response spectrum and photointensity-modulated photocurrent spectroscopy measurements.

Description

LED light source system with controllable light intensity and flicker frequency in photoelectrochemical measurement

technical field

    The utility model belongs to the technical field of semiconductor photoelectrochemical testing, in particular to an LED light source system with controllable light intensity and flicker frequency in photoelectrochemical measurement.

Background technique

In recent years, in the field of semiconductor photoelectrochemical research, the development and application of various emerging photoelectrochemical research technologies, such as photocurrent-time response spectroscopy of semiconductor materials, light intensity modulation photocurrent spectroscopy and other measurement technologies, have developed rapidly. Among them, photocurrent-time response spectroscopy and light intensity modulation photocurrent spectroscopy are a powerful tool for studying the charge transfer mechanism and dynamics of semiconductor materials in the photoelectrochemical reaction process, and are important means to deeply understand the intrinsic nature of semiconductor photoelectrochemical processes. It plays a non-negligible role in promoting research in the fields of solar photovoltaics, photocatalysis, and photoelectrochemistry.

my country's current research on light intensity modulation photocurrent spectroscopy is in the initial stage. The instruments used for light intensity modulation photocurrent spectroscopy rely on self-owned equipment, and lack targeted integrated LED light source equipment.

Contents of the invention

The purpose of this utility model is to provide a LED light source system with controllable light intensity and flicker frequency in photoelectrochemical measurement, which can directly realize the measurement of photocurrent-time response spectrum with electrochemical workstation, and cooperate with electrochemical workstation and lock-in amplifier ( Or frequency response analyzer) can realize the measurement of light intensity modulated photocurrent spectrum.

The technical scheme adopted in the utility model is:

An LED light source system with controllable light intensity and flicker frequency in photoelectrochemical measurement, characterized in that:

Including background light source, background light drive module, modulated light source, modulated light drive module, function switch and interface; background light source connected to background light drive module, modulated light source connected to modulated light drive module, background light drive module and modulated light drive module Both are connected to the function switching switch, and the interface is connected to the modulating optical drive module;

The background light drive module includes multivibrator, counter 74LS161, multi-way switch, OR chip 74LS32 1/4 and LED constant current driver PT4115; LED constant current driver PT4115 is connected with the background light source, OR chip 74LS32 1/4 4 connected with the function switching switch;

The modulated light drive module sequentially includes an optocoupler relay and an adding circuit, and the core of the adding circuit is a power amplifier; the optocoupler relay is connected to a function switching switch, and the modulated light source is connected to the power amplifier;

The Vcc end of the interface is connected to the optocoupler relay, the GND end and the modulation signal end are connected to both sides of the power amplifier, and the reference signal is grounded.

The multivibrator includes a timer 555, the variable resistor Rs1 and the resistor R1 are connected in series to the timer 555, the resistor R2, the capacitor C1, the capacitor C2, Rs1 and the resistor R1 are connected in series and parallel to the timer 555.

A variable resistor Rs2 is connected to the LED constant current driver PT4115, and the variable resistor Rs2 is connected in parallel with the background light source.

The utility model has the following advantages:

In the utility model, the light source part includes a background light source and a modulated light source, both of which use high-power full-color LED electronic components as light-emitting components. It is highly targeted and highly integrated, and can directly realize the measurement of photocurrent-time response spectrum and the measurement of light intensity modulated photocurrent spectrum. the

Description of drawings

Figure 1 is a schematic diagram of the arrangement of LED light sources.

Fig. 2 is the hardware structural diagram of the present utility model.

In Figure 1, gray is the modulation light source LED, and white is the background light source LED.

Detailed ways

The utility model is described in detail below in conjunction with specific embodiments.

The utility model relates to an LED light source system with controllable light intensity and flicker frequency in photoelectrochemical measurement, comprising a background light source, a background light drive module, a modulation light source, a modulation light drive module, a function switching switch and an interface. The background light source is connected to the background light drive module, the modulated light source is connected to the modulated light drive module, both the background light drive module and the modulated light drive module are connected to a function switching switch, and the interface is connected to the modulated light drive module.

The background light drive module includes multivibrator, counter 74LS161, multi-way switch, OR chip 74LS32 1/4 and LED constant current driver PT4115; LED constant current driver PT4115 is connected with the background light source, OR chip 74LS32 1/4 4 is connected with the function switching switch. The multivibrator includes a timer 555, the variable resistor Rs1 and the resistor R1 are connected in series to the timer 555, the resistor R2, the capacitor C1, the capacitor C2, Rs1 and the resistor R1 are connected in series and parallel to the timer 555. The multivibrator realizes the generation of the reference pulse signal, and the set pulse period T=0.7(R1+RS1+2R2)C1. The counter chip 74LS161 outputs the digital signals of the frequency division by 2, 4, 8 and 16 of the reference pulse signal at the output terminals Q0-Q3 respectively. Set to select 1 output of the multi-channel frequency division signal. The output frequency division signal and the signal of the function switching switch are input to the DIM terminal of the LED constant current driver PT4115 after OR gate calculation. When the function switching switch is "0", the DIM terminal is the step signal selected by the multi-channel switching switch, and the LED constant current driver PT4115 drives the background light source to achieve the same flickering state as the frequency of the DIM terminal; when the function switching switch is "1" , the DIM terminal is 1, and the LED constant current driver PT4115 drives the background light source to always be on. LED constant current driver PT4115 is a step-down constant current source with continuous inductor current conduction mode. In parallel, by adjusting the size of the variable resistor Rs2, the LED constant current driver PT4115 can output 200mA--1200mA constant DC, so as to realize the control of the brightness (light intensity) of the background light.

The modulating optical drive module sequentially includes an optocoupler relay and an adding circuit, and the core of the adding circuit is a power amplifier. The optocoupler relay is connected to the function switching switch, and the modulated light source is connected to the power amplifier. The optocoupler relay is used to control the power supply end of the power amplifier. The addition circuit with the power amplifier as the core realizes the superposition of the modulation signal and the DC reference signal, and realizes the alternating change of light and dark on the basis of maintaining a certain brightness of the modulated light source. By adjusting the amplitude of the modulation signal and the DC reference signal, the ratio of the light intensity change intensity of the modulated light source to the total light source intensity (light intensity of the background light source + light intensity of the modulated light source) can be adjusted. In the photoelectrochemical measurement system, in order to ensure the linearity and stability of the measurement system, this ratio is generally adjusted to 5%-15%.

The Vcc end of the interface is connected to the optocoupler relay, the GND end and the modulation signal end are connected to both sides of the power amplifier, and the reference signal is grounded.

The utility model can realize two working modes:

1. Modulation flashing mode:

When the function switching switch is switched to the modulating flashing mode, the output state of the function switching switch is "1". After the calculation of the OR gate chip, the DIM terminal of the LED constant current driver PT4115 is "1", and the LED constant current driver PT4115 drives the background light source normally. On; when the state of the optocoupler relay is "1", the power of the power amplifier is turned on. The modulated light source LED is driven by a power amplifier, and the power amplifier and surrounding resistors form an adding circuit to superimpose the DC reference signal and the modulating signal. The power amplifier superimposes the input modulation signal and the DC reference signal to the modulation light source. On the basis of maintaining a certain brightness of the modulation light source, it realizes the alternating light and dark changes of the modulated light source. This alternating light and dark change is controlled by the change of the modulation signal. In order to make the brightness of the light source proportional to the input current, the system introduces a DC reference signal so that the modulated light source can work at a certain brightness. The modulation signal is generally generated by an external lock-in amplifier, and the frequency range of the signal is 0.1Hz-1,000,000Hz. The modulated flicker mode of the light source system can be used with the lock-in amplifier and the electrochemical workstation to measure the light intensity modulated photocurrent spectrum of semiconductor materials.

2. Ultra-low frequency flashing mode:

When the function switching switch is switched to the ultra-low frequency flashing mode, the output state of the function switching switch is "0". After the calculation of the OR gate chip, the DIM terminal of the LED constant current driver PT4115 is the step signal of the other input terminal of the OR gate, and the backlight The light source achieves the same flickering state as the frequency of the DIM terminal; when the state of the optocoupler relay is "0", the power of the power amplifier is turned off, so that the modulating light source part does not work. The timer 555 chip and peripheral circuits form a multivibrator to generate a reference pulse signal. In this example, the period is set to 2 s. The chip of the counter 74LS161 is output as a frequency division signal, and the digital signals of the frequency division by 2, 4, 8 and 16 of the reference pulse signal are respectively output at the output end, and the periods of 4 s, 8 s, and 16 s can be obtained And 32 s step signal. These step signals are input to the multi-way switch. Through the setting of the multi-way switch, one of the multi-way step signals is selected to be output to the DIM terminal of the LED constant current driver PT4115, so that the background light source LED can achieve the same step signal Blinks at the same frequency. The ultra-low frequency flickering mode of this light source system can be used with the electrochemical workstation to measure the photocurrent time response curve of semiconductor materials.

The content of the utility model is not limited to the examples listed, and any equivalent transformations taken by those skilled in the art to the technical solution of the utility model by reading the specification of the utility model are covered by the claims of the utility model.

Claims (3)

1. light intensity and the controlled LED light source system of flicker frequency in Optical Electro-Chemistry measurement, is characterized in that:

Comprise background light source, bias light driver module, modulated light source, light modulated driver module, function change-over switch and interface; Background light source access bias light driver module, modulated light source access light modulated driver module, the equal access function change-over switch of bias light driver module and light modulated driver module, interface and light modulated driver module join;

Bias light driver module comprises multivibrator, counter 74LS161, multi-channel switch or door chip 74L,S32 1/4 and LED constant-flow driver PT4115 successively; LED constant-flow driver PT4115 and background light source join, or door chip 74L,S32 1/4 joins with function change-over switch;

Light modulated driver module comprises light coupling relay and add circuit successively, and the core of add circuit is power amplifier; Light coupling relay access function change-over switch is joined, modulated light source access power amplifier;

The Vcc termination of interface enters light coupling relay, and GND end and modulation signal termination enter power amplifier both sides, reference signal ground connection.

2. light intensity and the controlled LED light source system of flicker frequency in Optical Electro-Chemistry measurement according to claim 1, is characterized in that:

Multivibrator includes timer 555, and access timer 555 after variable resistor Rs1 and resistance R 1 series connection, accesses timer 555 after the series and parallel of resistance R 2, capacitor C 1, capacitor C 2 and Rs1 and resistance R 1.

3. light intensity and the controlled LED light source system of flicker frequency in Optical Electro-Chemistry measurement according to claim 2, is characterized in that:

On LED constant-flow driver PT4115, be connected to variable resistor Rs2, variable resistor Rs2 is in parallel with background light source.