KR100787081B1 - Optical sensor module remove the sun lighting and around light - Google Patents

Abstract

An optical sensor module is provided to prevent an erroneous operation due to saturation by forming an anti-saturation circuit therein, and improve reliance property of the optical sensor module by being operated only light emitting signal when the light emitting signal, solar light and peripheral light. A photodiode(PD) is performed to receive an emission signal, solar light, and peripheral light, and to convert the emission signal, the solar light, and the peripheral light to current. A first transistor(Q1) is formed to amplify an output of the photodiode and to output the amplified output. An anti-saturation circuit(22) is formed to prevent saturation of the first transistor by feeding back the output of the first transistor in response to the output of the photodiode. The anti-saturation circuit includes an inductor, a second transistor(Q2) having, and an integration circuit. The second transistor includes a collector connected to an anode of the photodiode, an emitter connected to the inductor, and a base connected to an emitter of the first transistor, and is turned on/off in response to an emitter voltage of the first transistor. The integration circuit delays the second transistor during a predetermined time.

Description

Optical sensor module remove the sun lighting and around light}

1 shows a sensor unit of a conventional vehicle detection apparatus.

2 shows an optical sensor module including a saturation prevention circuit according to an embodiment of the present invention.

The present invention relates to a detection device for detecting an optical signal, and more particularly, to a saturation prevention circuit of an optical sensor module resistant to interference of sunlight or ambient light.

The optical sensor module is a device that detects and detects an object using light. The optical sensor module detects light received from the outside to identify the object or scans the light to receive the reflected light to identify the object. In addition, the optical sensor module is provided with a light emitting unit for scanning the light and a light receiving unit, respectively, the light receiving unit to scan the light to detect the presence or absence of light to identify the object. The optical sensor module is used for the purpose of detecting an object to be detected indoors or outdoors.

1 shows a sensor unit of a conventional vehicle detection apparatus.

The sensor unit includes the light emitting unit 10 and the light receiving unit 20 and is disposed to correspond to each other. The light emitting unit 10 includes a plurality of light emitting sensors, and the light receiving unit 20 includes a plurality of light receiving sensors. The plurality of light emitting sensors and the light receiving sensors each have a form arranged vertically about one axis. The sensor unit is a method in which the light receiving sensors of the light receiving unit 20 detect the light emission signals scanned by the light emitting sensors of the light emitting unit 10. In this case, when the vehicle is introduced between the light emitting unit 10 and the light receiving unit 20, the light emission signal scanned by the light emitting unit 10 is partially blocked by the vehicle. The light receiving unit 20 detects the presence or absence of a light emission signal received from the light emitting unit 10 and classifies the presence or absence of a vehicle and a vehicle type.

However, the light receiving unit 20 is not a light emission signal scanned by the light emitting unit 10, the ambient light reflected from the outside, sunlight coming in direct sunlight and muddy water due to weather changes in the presence of the vehicle in the presence or absence of the vehicle And there was a problem in carrying out vehicle separation.

In particular, the light receiving unit 20 may be provided with a light shielding film on top of the light receiving unit 20 to prevent ambient light or sunlight caused by reflection, but the light receiving unit 20 receives light by direct sunlight incident at a low altitude in the morning or evening There was a problem that the device malfunctions.

Accordingly, an object of the present invention is to provide an optical sensor module that is strong against interference such as sunlight and ambient light. In addition, to provide an optical sensor module that prevents malfunction in response to direct sunlight received by a low altitude.

An optical sensor module according to an aspect of the present invention for achieving the above technical problem includes a photodiode, a first transistor, a saturation prevention circuit.

The photodiode receives the light emission signal, the sun and the ambient light, and converts the received signal into a current to output. The first transistor amplifies and outputs the output of the photodiode. The saturation prevention circuit may feed back the output of the first transistor that operates in response to the output of the photodiode to prevent saturation of the first transistor.

The saturation prevention circuit includes an inductor, a second transistor, and an integrating circuit.

The collector of the second transistor is connected to the anode of the photodiode, the emitter is connected to the inductor, and the base is connected to the emitter of the first transistor to turn on / turn in response to the emitter voltage of the first transistor. Is off. The integrating circuit may delay the operation of the second transistor for a predetermined time.

The integrating circuit may include a first node, a first resistor, a second resistor, and a capacitor. The first resistor is connected between the emitter of the first transistor and the first node. The second resistor is connected between the first node and the base of the second transistor. The capacitor is connected between the first node and ground.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the embodiments of the present invention, reference should be made to the accompanying drawings that illustrate embodiments of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

2 shows an optical sensor module 25 including a saturation prevention circuit 22 according to an embodiment of the present invention.

Referring to FIG. 2, the optical sensor module 25 includes a light receiving circuit 12, a saturation prevention circuit 22, and an amplification circuit 26.

The light receiving circuit 12 includes first to fourth resistors R1 to R4, a first capacitor C1, a photo diode PD, and a first transistor Q1.

The cathode of the photodiode PD is connected to the power supply voltage VCC through the first resistor R1. An anode of the photodiode PD is connected to a base of the first transistor Q1. The first capacitor C1 is connected between a cathode of the photodiode PD and a ground. The collector of the first transistor Q1 is connected to the cathode of the photodiode PD through a second resistor R2. The third resistor R3 is connected between the emitter and the ground of the first transistor Q1. The fourth resistor R4 is connected between the cathode of the photodiode PD and the base of the first transistor Q1.

The first resistor R1 and the first capacitor C1 are noise elimination integrated circuits for removing noise from the power supply voltage VCC. The photodiode PD receives an optical signal from the outside and converts the optical signal into an electrical signal.

That is, the light emitting unit 10 receives the light emission signal, the sunlight, and the ambient light, and outputs a current signal corresponding to the intensity of the light signal.

The first transistor Q1 is turned on by receiving the current signal through a base. As the first transistor Q1 is turned on, the power supply voltage VCC flows to the ground through the second resistor R2 and the third resistor R3. That is, a voltage drop occurs in the second resistor R2 and the third resistor R3.

The fourth resistor R4 is a noise removing resistor for removing noise coming into the photodiode PD.

The light emission signal scanned to the light emitting unit 10 is a micro size signal, which is a very small signal. The photodiode PD of the light receiving circuit 12 detects the light emitting signal scanned by the light emitting unit 10 and converts the light emitting signal into a current corresponding to the magnitude of the light emitting signal to output the output node OUT of the first transistor Q1. Is output to the amplification circuit 26 through

The saturation prevention circuit 22 includes a first node NO1, a second transistor Q2, a fifth resistor R5, a sixth resistor R6, a second capacitor C2, and an inductor L1. .

The fifth resistor R5 is connected between the emitter of the first transistor Q1 and the first node NO1. The sixth resistor R6 is connected between the first node NO1 and the base of the second transistor Q2. The second capacitor C2 is connected between the first node NO1 and ground. The collector of the second transistor Q2 is connected to the anode of the photodiode PD, the emitter is connected to ground through the inductor L1, and the base is connected to the sixth resistor R6.

When the magnitude of the optical signal received by the photodiode PD is a strong direct ray such as ambient light or sunlight, the first transistor Q1 is saturated. That is, the first transistor Q1 no longer detects an optical signal and malfunctions. In this case, the saturation prevention circuit 22 receives the current generated by ambient light or sunlight from the photodiode PD and outputs it to ground, thereby preventing saturation of the first transistor Q1.

That is, in the saturation prevention circuit 22, incident light (sun light or ambient light) incident on the photodiode PD is increased, and accordingly, the current flowing in the first transistor Q1 is increased so that the first light is increased. This circuit is operated when one transistor Q1 is saturated.

When the photocurrent of the photodiode PD is increased by direct sunlight or ambient light, the emitter voltage of the first transistor Q1 is increased, and when the voltage is about 0.7V or more, the second transistor Q2 Current flows through the base to lower the impedance between the collector and emitter of the second transistor Q2. At this time, the photocurrent of the photodiode PD flows to the second transistor Q2 and the inductor L1, so that the photocurrent flowing to the base of the first transistor Q1 is reduced, thereby saturating the first transistor Q1. Prevent and maintain an active state at all times.

Therefore, when the light emitting signal, the solar light, and the ambient light are input together to the photodiode PD, the second transistor Q2 operates the first transistor Q1 by using only the light emitting signal to increase the reliability of the optical sensor module. Can be.

The fifth resistor R5, the sixth resistor R6, and the second capacitor C2 form a T-type integrated circuit to prevent feedback due to an AC component. In addition, the T-type integrating circuit delays the current input to the second transistor Q2 for a predetermined time. In the present embodiment, although the inductor L1 uses the high frequency current flowing through the second transistor Q2, the resistor R element may be used when the low frequency is used.

The amplifier circuit 26 includes a third capacitor C3, a fourth capacitor C4, a first diode D1, a second diode D2, a seventh resistor R7, a second node NO2, and a third capacitor C3, a fourth capacitor C4. Node NO3.

The third capacitor C3 is connected between the output node OUT and the second node NO2. The first diode D1, the second diode D2, and the seventh resistor R7 are connected in parallel between the second node NO2 and the third node NO3. The fourth capacitor C4 is connected between the third node NO3 and ground.

The third capacitor C3 temporarily stores the voltage of the output node OUT. The first and second diodes D1 and D2 amplify the voltage of the output node OUT to a predetermined reference voltage Vref, and the first and second diodes D1 and D2 are referred to as reference voltages. It protects the circuit by preventing the voltage over Vref). The seventh resistor R7 and the fourth capacitor C4 delay the Vout output for a predetermined time to perform stable output.

The amplification circuit 26 may be variously designed according to a method that the user wants to amplify and output, and the like.

Although the present embodiment has been described in that the optical sensor module is installed and operated in the light receiving unit of the vehicle detecting apparatus, the optical sensor module may be used in any device into which the optical sensor module is inserted, but is not limited thereto.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

By implementing the saturation prevention circuit in the optical sensor module according to the present invention as described above, there is an effect that can prevent the malfunction when the optical sensor module is saturated by direct sunlight due to sunlight, ambient light.

In addition, the light sensor module can increase the reliability of the light sensor module by operating only the light emission signal when the light signal, sunlight and ambient light are input together.

Claims (3)

A photodiode that receives the light emission signal, sunlight, and ambient light and converts the light into current; A first transistor for amplifying and outputting the output of the photodiode; And And a saturation prevention circuit for feeding back the output of the first transistor that operates in response to the output of the photodiode to prevent saturation of the first transistor. The method of claim 1, wherein the saturation prevention circuit Inductors; A collector is connected to an anode of the photodiode, an emitter is connected to the inductor, and a base is connected to an emitter of the first transistor, the second transistor being turned on / off in response to the emitter voltage of the first transistor. ; And And an integrated circuit for delaying the second transistor by a predetermined time. The method of claim 2, wherein the integrating circuit A first node; A resistor connected between the emitter of the first transistor and the first node; A second resistor connected between the first node and the base of the second transistor; And a capacitor connected between the first node and ground.

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