CN102661789B - a light detector - Google Patents

Abstract

The invention discloses an optical detector which comprises a current supply circuit and a voltage output circuit, wherein the current supply circuit and the voltage output circuit are connected with a conversion module; a current signal outputted by the current supply circuit is served as an input signal of the conversion module; the current signal is converted into a voltage signal under the conversing effect of the conversion module; a current output chip is contained in the current supply circuit of the optical detector; and a coating film is integrated with the interior of the current output chip. In the optical detector provided by the invention, the current signal is converted into the voltage signal through the conversion module and the voltage signal is utilized to perform optical detection, so that the error of current detection is reduced. Besides, the current output chip, of which the interior is integrated with the coating film, is contained in the current supply circuit of the optical detector, so that the optical detector has different sensitivities for the light sources with different wavelengths and is fit for and matched with a daylight vision curve of human eyes, and the measurement error brought by a glass optical filter is further avoided.

Description

a light detector

technical field

The invention relates to the technical field of visible light detection, in particular to a light detector.

Background technique

Optical detectors, also known as optical detectors, are the primary part of optical receivers. Optical detectors are an important part of optical fiber sensors. Therefore, the performance indicators of optical detectors will directly affect the performance of sensors.

The photodetector in the prior art is composed of a silicon photocell, a filter glass and opal glass. The photodetector can detect the light power incident on its surface, and convert the change of the light power into a corresponding current signal.

However, since the output of the existing photodetector is a current signal, and the current signal is relatively weak, it is easy to be interfered by the outside world; in addition, the signal of the silicon photocell is linearly output, a strong light source outputs a large signal, and a very weak light source outputs a very weak signal. Small, and the reference signal at the signal acquisition end is fixed, so it is necessary to switch to the corresponding gear for light sources of different intensities to meet the measurement requirements. However, there are errors in the consistency between different gears, which will cause errors in the measurement results. Therefore, the accuracy of the measurement results will be affected; at the same time, due to the use of filter glass in the existing photodetectors, the filter glass will be affected by environmental factors such as temperature and humidity, which will also cause inaccurate measurement results. .

Contents of the invention

In view of this, an embodiment of the present invention provides a photodetector to solve the problem of inaccurate measurement caused by using filter glass and silicon photocells in the photodetector in the prior art.

The present invention provides a photodetector. The photodetector includes: a current supply circuit, a conversion module and a voltage output circuit, and the conversion module is respectively connected to the current supply circuit and the voltage output circuit;

The current supply circuit outputs a current signal, and inputs the current signal into the input interface of the conversion module, wherein the current supply circuit includes a current output chip with an internal integrated coating;

The conversion module converts the received current signal into a voltage signal, and outputs it to the voltage output circuit;

The voltage signal of the conversion module output by the voltage output circuit measures the intensity of the light source.

Preferably, the power input interface of the current output chip is connected with a power filter circuit.

Preferably, the conversion module includes two differential voltage input interfaces, non-inverting and inverting;

A sampling resistor is connected in series between the current output interface of the current output chip and the ground, and the current signal forms a differential voltage at both ends of the sampling resistor, and under the action of the balance resistor, the equal bias current of the in-phase and reverse-phase voltage input interfaces is guaranteed The resulting pressure drop is equal.

Preferably, the voltage input interface of the conversion module is connected with a filter circuit.

Preferably, a resistor is connected in series between the voltage output interface of the conversion module and the reference interface, and one end close to the reference interface is grounded.

Preferably, the voltage output interface of the conversion module is connected with a high-frequency filter circuit.

其中I_out为电流输出芯片电流输出接口输出的电流信号，S为该电流输出芯片的敏感系数，E_V为实际照度，E_o为零点照度。Preferably, the current output chip outputs a current signal according to the following formula:

Among them, I _out is the current signal output by the current output interface of the current output chip, S is the sensitivity coefficient of the current output chip, E _V is the actual illuminance, and E _o is the zero-point illuminance.

其中V_out为转换模块的电压输出接口输出的电压信号，S为该转换模块的敏感系数，d为光源与光探测器之间的距离，E_o为零点照度，candela为光强。Preferably, the conversion module outputs a voltage signal according to the following formula:

Where V _out is the voltage signal output by the voltage output interface of the conversion module, S is the sensitivity coefficient of the conversion module, d is the distance between the light source and the photodetector, E _o is the zero-point illuminance, and candela is the light intensity.

The invention provides a photodetector, which includes a current supply circuit and a voltage output circuit connected to a conversion module, wherein the current signal output by the current supply circuit is used as the input signal of the conversion module, through the conversion of the conversion module The current signal is converted into a voltage signal, and in the present invention, the current supply circuit includes a current output chip with an internal integrated coating. Because the current signal is converted into a voltage signal by the conversion module in the photodetector of the present invention, and the light detection is performed through the voltage signal, thereby reducing the error of current detection, and because the current supply circuit in the present invention contains an internal integrated coating Therefore, it can have different sensitivities for light sources of different wavelengths, which matches the photopic vision curve of the human eye, thus avoiding the measurement error caused by the filter glass.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is a schematic diagram of the internal circuit connection structure of the photodetector provided by the present invention;

Fig. 2 is a schematic structural diagram of the current output chip provided by the present invention;

Fig. 3 is a Vλ curve diagram of a current output chip including an internal integrated coating in the present invention.

Detailed ways

In order to effectively improve the accuracy of the photodetector and improve the anti-interference ability of the photodetector, the embodiment of the present invention provides a new type of photodetector

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In the present invention, the photodetector includes: a current supply circuit, a conversion module and a voltage output circuit, and the conversion module is connected to the current supply circuit and the voltage output circuit respectively;

The current supply circuit outputs a current signal, and inputs the current signal into the input interface of the conversion module, wherein the current supply circuit includes a current output chip with an internal integrated coating;

The conversion module converts the received current signal into a voltage signal, and outputs it to the voltage output circuit;

The voltage signal of the conversion module output by the voltage output circuit measures the intensity of the light source.

Because the current signal is converted into a voltage signal by the conversion module in the photodetector of the present invention, and the light detection is performed through the voltage signal, thereby reducing the error of current detection, and because the current supply circuit in the present invention contains an internal integrated coating Therefore, it can have different sensitivities for light sources of different wavelengths, which matches the photopic vision curve of the human eye, thus avoiding the measurement error caused by the filter glass.

A specific embodiment will be described below.

FIG. 1 is a schematic diagram of the internal circuit connection structure of the photodetector provided by the present invention. The photodetector includes a current supply circuit, a conversion module and a voltage output circuit, and the conversion module is connected to the current supply circuit and the voltage output circuit respectively.

In the present invention, the conversion module is the U12 module (instrument amplifier) in FIG. ) and IN+ (3), reference signal interface REF (5), voltage output interface OUT (6) and two sensitivity adjustment interfaces RG (1, 8).

There are two voltage input interfaces in the conversion module, which are respectively connected to positive and negative voltages. For example, the working voltage required by the conversion module is respectively plus and minus 5V. Negative 5V power supply, namely +5VO and -5VO.

In addition, in order to reduce the interference received by the input power and improve the stability of the power input in the present invention, the voltage input interfaces of the conversion modules can be respectively connected to power filter circuits in the present invention. Specifically, in Figure 1, the input power +5VO is grounded through capacitor C27, the power input interface 7 of the conversion module is connected between the power supply and capacitor C27, the same input power -5VO is grounded through capacitor C29, and the power input interface of the conversion module 4 is connected between the power supply and capacitor C29.

The two current input interfaces 2 and 3 of the conversion module are respectively connected to the current supply circuit. The specific current supply circuit includes a current output chip, and in the present invention, in order to improve the sensitivity of light detection for different light sources, the current output chip adopts an internal Integrated coating current output chip. As shown by D12 in FIG. 1 , specifically, in the present invention, the current output chip integrated with coating can be a chip of OSRAM Company.

FIG. 2 is a schematic structural diagram of the current output chip provided by the present invention. The chip includes three interfaces, namely a power input interface Vcc, a current output interface I _out and a grounding interface GND.

Since the chip can convert the light intensity signal into a current signal, it can provide input current for the conversion module. The specific current signal output by the chip can be expressed by the following formula:

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; log</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; V</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; )</span>$

Where I _out is the current signal output by the current output interface of the current output chip, S is the sensitivity coefficient of the current output chip, E _V is the actual illuminance, E _o is the zero-point illuminance, and E _o =1lx/SensitivityS=10μA.

Specifically, when the chip of OSRAM Company is used in the present invention, the chip is internally integrated (Vλ), as shown in Figure 3, the Vλ curve of the chip, the horizontal axis in this figure is the light wavelength λ, and the vertical axis is the response sensitivity . As shown in the figure, the chip can perfectly match the visual curve of the human eye, and has good thermal stability. Therefore, there is no need to use filter glass in the photodetector of the present invention, thereby avoiding measurement errors caused by environmental factors of the filter glass.

D12 in Figure 1 is a simplified diagram of the above-mentioned current output chip. The chip leads to 4 interfaces, namely the power input interface Vcc (3), the current output interface I _out (4) and the ground interface GND (1, 2). Two of the grounding interfaces 1 and 2 are connected in series and are grounded through wires. In order to ensure the stability of the power input of the chip and reduce external interference to the power supply, the power input interface 3 of the chip is also connected with a power filter circuit in the present invention. . For example, when the input power of the chip is +5v, the +5v power supply +5VO is grounded through the capacitor C28, and the power input interface 3 of the chip is connected between the power supply and the capacitor C28.

After the chip outputs current, the output current is used as the input current of the conversion module. The conversion module includes two differential voltage input interfaces of the same phase and the reverse phase; different resistances are connected in series between the current output interface of the current output chip and each voltage input interface.

Specifically as shown in Figure 1, a resistor R78 is connected in series between the current output interface 4 of the current output chip and the current input interface 3 of the conversion module, and resistors R49 and R67 are connected in series with the voltage input interface 2, and in order to ensure the The conversion module provides negative current to ground between resistors R49 and R67.

A sampling resistor R49 is connected in series between the current output interface 4 of the current output chip and the ground. The current signal forms a differential voltage at both ends of the sampling resistor and is connected to U12. The resistors R67 and R78 are balanced resistors to ensure that the two input terminals are "equal" The voltage drops produced by the bias currents are equal and cancel each other out.

The voltage input interfaces 2 and 3 of the conversion module receive the input current signal, and the resistor R46 connected in series between the sensitivity adjustment interfaces 1 and 8 of the conversion module plays a role in adjusting the gain and can be used to match the reference signal at the acquisition end.

After the conversion module starts working, it converts the input current signal into a voltage signal, and outputs the converted voltage signal through the voltage output interface 6. Specifically, the voltage signal input by the conversion module can be expressed by the following formula:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; log</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="candela\; d"\; filenames="HDA00001599876400011.png"\; state="\{\{state\}\}">candela</figure-callout></span><figure-callout\; id="2"\; label="candela\; d"\; filenames="HDA00001599876400011.png"\; state="\{\{state\}\}">\; </figure-callout>}}{{\mathrm{<span\; class="notranslate">\; </span>}}^{}}<span\; class="notranslate">\; )</span>$

Among them, V _out is the voltage signal output by the voltage output interface of the conversion module, S is the sensitivity coefficient of the conversion module, d is the distance between the light source and the photodetector, E _o is the zero-point illuminance, and candela is the light intensity. Since the sensitivity coefficient S of the conversion module and the zero-point illuminance E _o are inherent characteristics of the detector, in order to facilitate measurement, when determining these two parameters, S and E _o can be deduced from two standard light source intensity values, for example, using $V_{\mathrm{out}1}=S*\log \left(\frac{\mathrm{candela}1}{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA00001599876400011.png"\; state="\{\{state\}\}">d</figure-callout>}}^2*{\mathrm{E.}}_0}\right)$ and $V_{\mathrm{out}2}=S*\log \left(\frac{\mathrm{candela}2}{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA00001599876400011.png"\; state="\{\{state\}\}">d</figure-callout>}}^2*{\mathrm{E.}}_0}\right)$ Then S and E _o can be calculated, because V _out1 , V _out2 , candela1, candela2 and d are all known parameters, and S and E can be calculated through the above two equations.

According to the voltage signal output by the voltage output interface of the above-mentioned conversion module, the output of the photodetector in the present invention satisfies the log function curve, so the measurement range of the photodetector in the present invention is wide, that is, within a fixed signal range The measurement of signals of different strengths can be completed, and the acquisition end only needs to match the reference signal, and there is no need to switch gears, thereby avoiding measurement errors caused by inconsistencies between gears.

After the conversion module outputs a voltage signal, in order to provide a reference point for the voltage signal, in the present invention, a resistor is connected in series between the voltage output interface of the conversion module and the reference interface, and one end close to the reference interface is grounded. As shown in Fig. 1, a resistor R79 is connected in series between the voltage output interface 6 and the reference interface 5 of the conversion module, and one end close to the reference interface 5 is grounded, thereby providing a reference point for the output of the voltage signal.

After the output voltage of the conversion module, in order to ensure the anti-interference ability of the voltage signal and improve the accuracy of detection, in the present invention, the voltage output interface of the conversion module is connected with a high-frequency filter circuit. As shown in Figure 1, the voltage output interface 6 of the conversion module is connected in series with the resistor R64, and the other ends of the resistor R64 are respectively the output terminals of the output voltage, and the output terminals of the output voltage are grounded through the capacitor C38, so as to realize the filtering effect.

The invention provides a photodetector, which includes a current supply circuit and a voltage output circuit connected to a conversion module, wherein the current signal output by the current supply circuit is used as the input signal of the conversion module, through the conversion of the conversion module The current signal is converted into a voltage signal, and in the present invention, the current supply circuit includes a current output chip with an internal integrated coating. Because the current signal is converted into a voltage signal by the conversion module in the photodetector of the present invention, and the light detection is performed through the voltage signal, thereby reducing the error of current detection, and because the current supply circuit in the present invention contains an internal integrated coating Therefore, it can have different sensitivities for light sources of different wavelengths, which matches the photopic vision curve of the human eye, thus avoiding the measurement error caused by the filter glass.

Those skilled in the art can also understand that various illustrative logical blocks (illustrative logical blocks), units, and steps listed in the embodiments of the present invention can be implemented by electronic hardware, computer software, or a combination of both. To clearly demonstrate the interchangeability of hardware and software, the various illustrative components, units and steps above have generically described their functions. Whether such functions are implemented by hardware or software depends on the specific application and overall system design requirements. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be understood as exceeding the protection scope of the embodiments of the present invention.

The various illustrative logic blocks or units described in the embodiments of the present invention can be implemented by general-purpose processors, digital signal processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to implement or operate the described functions. The general-purpose processor may be a microprocessor, and optionally, the general-purpose processor may also be any conventional processor, controller, microcontroller or state machine. A processor may also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration to accomplish.

The steps of the method or algorithm described in the embodiments of the present invention may be directly embedded in hardware, a software module executed by a processor, or a combination of both. The software modules may be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM or any other storage medium in the art. Exemplarily, the storage medium can be connected to the processor, so that the processor can read information from the storage medium, and can write information to the storage medium. Optionally, the storage medium can also be integrated into the processor. The processor and the storage medium can be set in the ASIC, and the ASIC can be set in the user terminal. Optionally, the processor and the storage medium may also be set in different components in the user terminal.

In one or more exemplary designs, the above functions described in the embodiments of the present invention may be implemented in hardware, software, firmware or any combination of the three. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media and communication media that facilitate transfer of a computer program from one place to another. Storage media may be any available media that can be accessed by a general purpose or special computer. For example, such computer-readable media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other device that can be used to carry or store instructions or data structures and Other medium of program code in a form readable by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. In addition, any connection is properly defined as a computer-readable medium, for example, if the software is transmitted from a web site, server, or other remote source via a coaxial cable, fiber optic computer, twisted pair, digital subscriber line (DSL) Or transmitted by wireless means such as infrared, wireless and microwave are also included in the definition of computer readable media. Disks and discs include compact discs, laser discs, optical discs, DVDs, floppy discs, and Blu-ray discs. Disks usually reproduce data magnetically, while discs usually reproduce data optically with lasers. Combinations of the above can also be contained on a computer readable medium.

The above description shows and describes a preferred embodiment of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various Various other combinations, modifications, and environments can be made within the scope of the inventive concept described herein, by the above teachings or by skill or knowledge in the relevant field. However, changes and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should all be within the protection scope of the appended claims of the present invention.

Claims (6)

1. a photo-detector, is characterized in that, described photo-detector comprises: electric current provides circuit, modular converter and voltage follower circuit, and modular converter provides circuit to be connected with voltage follower circuit with electric current respectively;

Described electric current provides circuit output current signal, and described current signal is inputted to the input interface of described modular converter, wherein this electric current provides the electric current that comprises inner integrated plated film in circuit pio chip, the following formula output current signal of described electric current pio chip basis: i wherein _outfor the current signal of electric current pio chip electric current output interface output, S ₁for the sensitivity coefficient of this electric current pio chip, E _vfor actual illumination, E _ofor illumination at zero point;

Modular converter is converted to voltage signal by the current signal receiving, and exports to voltage follower circuit, the following formula output voltage signal of described modular converter basis:

v wherein _outfor the voltage signal that the Voltage-output interface of modular converter is exported, S ₂for the sensitivity coefficient of this modular converter, d is the distance between light source and photo-detector, E _ofor illumination at zero point, candela is light intensity;

The voltage signal of the described modular converter of voltage follower circuit output, for the intensity of measurement light source.

2. photo-detector as claimed in claim 1, is characterized in that, the power input interface of described electric current pio chip is connected with electric source filter circuit.

3. photo-detector as claimed in claim 1 or 2, is characterized in that, described modular converter comprises homophase and anti-phase two differential voltage input interfaces;

The sampling resistor of connecting between the electric current output interface of described electric current pio chip and ground, current signal forms differential voltage at sampling resistor two ends, and under balance resistance effect, guarantee that the pressure drop of the bias current generation that this homophase is equal with reverse voltage input interface equates.

4. photo-detector as claimed in claim 1, is characterized in that, the voltage input interface of described modular converter is connected with filtering circuit.

5. photo-detector as claimed in claim 1, is characterized in that, between the Voltage-output interface of described modular converter and referenced interface, is in series with resistance, and one end ground connection of close referenced interface.

6. photo-detector as claimed in claim 1, is characterized in that, the Voltage-output interface of described modular converter is connected with high-frequency filter circuit.

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