JP2654605B2 - Pulse laser light detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse laser light detecting device, and more particularly to a pulse laser light detecting device for judging the arrival direction of irradiated pulse laser light from a time difference between a plurality of irradiated pulse laser lights.

[0002]

2. Description of the Related Art FIG.
As shown in the figure, a plurality of optical systems 10-1 to 10-n having predetermined directions and a field of view, and an optical system 10-1
Photo-detecting elements 20-1 to 20-n for converting the pulsed laser beams from to 10-n into photocurrents, respectively;
Voltage conversion circuits 30-1 to 30-n for converting photocurrents from 0-1 to 20-n into voltage signals;
When the output voltage from 1 to 30-n is output by pulsed laser light, the magnitude of the output is compared with a predetermined threshold, and when the output exceeds the predetermined threshold, the comparison output is determined. The comparison circuits 40-1 to 40-n to be transmitted are compared with the time from when the output is generated to when the output exceeds the predetermined threshold value.
A discriminating circuit 60 for discriminating the output having the fastest time among the outputs of -n, and a display 70 for displaying the arrival direction of the pulsed laser beam applied to the apparatus from the discrimination result of the discriminating circuit 60
Is provided.

[0003] When there is a pulse laser beam which is directly irradiated to the device when the pulse laser beam is irradiated and a pulse laser beam which is reflected from an object around the device and is irradiated to the device, the respective pulse lasers are used. Light is incident on different optical systems depending on the direction of irradiation on the device. For example, optical system 1
When pulse laser light is irradiated on 0-1 and 10-2,
The optical system 10-1 is formed by the light detecting elements 20-1 and 20-2.
Each of the pulse laser beams from to 10-n is converted into a photocurrent. The photocurrents output from the light detection elements 20-1 and 20-2 are respectively converted into voltage conversion circuits 30-1 and 30-2.
And the photocurrents from the photodetectors 20-1 and 20-2 are converted into voltage signals. Voltage conversion circuit 30-
The voltage signals output from 1, 30-2 are input to comparison circuits 40-1, 40-2, respectively.

Here, the upper waveform shown in FIG. 4 is a voltage output waveform from the voltage conversion circuit 30-1, and the lower waveform is a voltage output waveform from the voltage conversion circuit 30-2. In this case, when the voltage outputs of the voltage conversion circuits 30-1 and 30-2 become larger than a predetermined reference value V _T (threshold level), the first and second comparison circuits 40-1 and 40-2 respectively output the first signals. Comparison output (threshold signal) and the second
The comparison output (threshold signal) of the
Is input to The discrimination circuit 60, the first comparing compares output and time generated from the respective generated time t _a and t _b of the second comparison output, the fastest output time exceeds a predetermined reference value V _T Is determined as the first comparison output.
In this case, the optical system 10- that outputs the first comparison output
The laser light irradiated to 1 is regarded as the directly irradiated pulse laser light. The display 6 displays the direction corresponding to the first comparison output, thereby accurately displaying the direction directly irradiated even if there is a pulsed laser beam reflected from the periphery of the device and applied to the device. Has functions.

[0005]

Conventionally, in this kind of pulse laser light detecting device, the fastest output of the output time generated as a result of comparing the photocurrent generated by the photodetector with a fixed reference value is obtained. Is displayed as the direction of the pulsed laser beam applied to the apparatus. For this reason, as shown in FIG. 5, when the intensity of the pulse laser light reflected on the periphery of the device and applied to the device is higher than the intensity of the laser beam directly applied to the detection device, the directly applied pulse laser pulsed laser for generating time t _b of the comparison output outputted by the output of the irradiated pulsed laser beam device is reflected by the peripheral device than the generation time t _a comparison output that is output by the output of light is faster There has been a problem that the direction of light irradiation is reflected at the periphery of the device and is erroneous as the direction of irradiation.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to directly irradiate the pulse laser light irrespective of the intensity of the pulse laser light directly radiated to the device and the intensity of the pulse laser light reflected and reflected around the device. An object of the present invention is to provide a pulse laser light detection device capable of distinguishing pulse laser light.

[0007]

According to the present invention, there are provided a plurality of focusing means for focusing pulsed laser light from a predetermined direction, and a plurality of focusing means provided corresponding to the plurality of focusing means, respectively. A plurality of light detection means, and a pulse laser light detection device that detects output signals from the plurality of light detection means and directly discriminates light, receives an output signal from the plurality of light detection means, A plurality of peak time measuring means for respectively transmitting a peak output signal when each of the plurality of output signals reaches a peak value, and receiving the plurality of peak output signals, and among the plurality of measured values, the time to reach a peak is the most. There is provided a pulse laser light detecting device comprising: a discriminating means for discriminating fast pulse laser light and discriminating the discriminated pulse laser light as direct light.

Further, according to the present invention, the plurality of peak time measuring means comprises a comparing circuit and a peak time measuring circuit, and the plurality of comparing circuits respectively output signals from the corresponding light detecting means. And comparing the output levels of the plurality of output signals with a predetermined threshold value, sending a timing signal when the output level is equal to or greater than the predetermined threshold value, and measuring the plurality of peak time periods. The circuit is
A pulse laser light detecting device is provided, wherein the pulse laser light detecting device receives the output signal and the timing signal, respectively, and sends a peak output signal to the determination means when the output signal reaches a peak value.

Further, according to the present invention, there is provided a pulse laser light detecting device further comprising display means for displaying the direction of the pulse laser light determined by the determination means.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a block diagram showing the configuration of one embodiment of the pulse laser light detection device according to the present invention.
In FIG. 1, pulse laser light is applied to each of a plurality of optical systems 1-1 to 1-n as light collecting means having a predetermined direction and a visual field. Each of the light detecting elements 2-1 to 2-n functioning as light detecting means is an optical system 1
The laser light from -1 to 1-n is converted into a photocurrent as an output current. Here, the voltage conversion circuits 3-1 to 3-n, the comparison circuits 4-1 to 4-n, and the peak time measurement circuits 5-1 to 5-1.
5-n functions as a peak time measuring means. The voltage conversion circuits 3-1 to 3-n respectively include the light detecting elements 2-1 to 2-
The photocurrent from n is converted to a voltage signal. Comparison circuit 4-1
When the output voltage from each of the voltage conversion circuits 3-1 to 3-n is an output by a pulsed laser beam, the output is compared with a predetermined threshold value. When the threshold value is exceeded, a comparison output (threshold signal) is sent out as a timing signal. The inputs of the peak time measuring circuits 5-1 to 5-n are respectively connected to the outputs of the comparing circuits 4-1 to 4-n and the outputs of the voltage converting circuits 3-1 to 3-n. Peak time measurement circuits 5-1 to 5
-N receives the timing signal, starts the measurement at the same time as the input of the timing signal,
When each of the voltage signals output from -n reaches a peak value, a peak output signal is transmitted. A discriminating circuit 6 functioning as a discriminating means receives the plurality of peak output signals, discriminates the pulse laser light having the plurality of peak output signals reaching the discriminating circuit fastest, and directly outputs the discriminated pulse laser light. Judge as light. A display unit 7 functioning as a display unit displays the arrival direction of the pulsed laser beam applied to the apparatus based on the result of the determination by the determination circuit 6.

When there is a pulse laser beam which is directly irradiated to the device when the pulse laser beam is irradiated, and a pulse laser beam which is reflected from an object around the device and is irradiated to the device, the respective pulse lasers are used. Light is incident on different optical systems depending on the direction of irradiation on the device. For example, optical system 1
When -1 and 1-2 are irradiated with pulse laser light, the pulse laser lights from the optical systems 1-1 to 1-n are converted into photocurrents by the photodetectors 2-1 and 2-2, respectively. The photocurrents output from the photodetectors 2-1 and 2-2 are input to voltage conversion circuits 3-1 and 3-2, respectively, and the photocurrents from the photodetectors 2-1 and 2-2 are voltage signals, respectively. Is converted to The voltage signals output from the voltage conversion circuits 3-1 and 3-2 are input to the comparison circuits 4-1 and 4-2 and the peak time measurement circuits 5-1 and 5-2, respectively.

Here, the upper waveform shown in FIG. 2 is a voltage output waveform from the voltage conversion circuit 3-1 and the lower waveform is a voltage output waveform from the voltage conversion circuit 3-2. In this case, when the voltage outputs of the voltage conversion circuits 3-1 and 3-2 become larger than a fixed reference value V _T (threshold level), the first and second comparison circuits 4-1 and 4-2 respectively output the first and second signals. A first timing signal as a comparison output and a second timing signal as a second comparison output are transmitted. The peak time measurement circuits 5-1 and 5-2 receive the first timing signal and the second timing signal, respectively, and start measurement. That is, the measurement is started when the voltage output becomes larger than a certain reference value V _T (threshold level).

At the time when the output waveforms of the voltage conversion circuits 3-1 and 3-2 reach their peaks (hereinafter referred to as peak times), that is, at the peak times t _a and t _b , the peak time measurement circuit 5- 1 outputs the first peak output signal to the discrimination circuit 6 from the peak time measurement circuit 5-2. The determination circuit 6 compares the peak time t _a with the peak time t _b to determine the first peak output signal in which the time at which the peak output signal occurred is the fastest,
The discriminated pulse laser light is discriminated as direct light. The display 7 displays the direction of the pulsed laser light corresponding to the first peak output signal.

Therefore, according to the present invention, even if the intensity of the pulse laser light reflected on the periphery of the device and applied to the device is higher than the intensity of the pulse laser light directly applied to the device, it is shown in FIG. the peak time t _a of the output waveform of the voltage conversion circuit 3-1 and 3-2, a peak output when the t _b is input to the determination circuit 6 so, the time to peak than directly reflected light Considering the nature of being fast, the discriminating circuit 6
In the above, it is possible to identify the directly irradiated pulse laser light by determining the first peak output signal in which the time when the peak output signal is generated is the fastest.

In the present embodiment, taking the case of two optical systems as an example, the peak time t _a and the peak time t _b based on the timing signals from the comparison circuits 4-1 and 4-2.
Then, the first peak output signal from the peak time measuring circuit 5-1 and the second peak output signal from the peak time measuring circuit 5-2 are sent to the discriminating circuit 6. However, if a timing signal generator (not shown) is provided for each of the peak time measuring circuits 5-1 and 5-2, the present embodiment can be performed without providing the comparing circuits 4-1 and 4-2. The same effect can be obtained.

[0016]

According to the present invention, even if the intensity of the pulse laser light reflected on the periphery of the device and applied to the device is higher than the intensity of the pulse laser light directly applied to the device,
As shown in FIG. 2, the peak outputs at the peak times t _a and t _b of the output waveforms of the voltage conversion circuits 3-1 and 3-2 are input to the discrimination circuit 6, so that the reflected light has a more peak than the direct light. In view of the property that the time to reach the peak is fast, the discrimination circuit 6 can discriminate the directly irradiated pulse laser light by discriminating the first peak output signal in which the peak output signal is generated the fastest. In addition, the pulse laser light directly irradiated can be distinguished regardless of the intensity of the pulse laser light directly irradiated to the device and the intensity of the pulse laser light reflected and irradiated around the device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a pulsed laser light detection device according to the present invention.

FIG. 2 is a diagram showing an output voltage waveform and a generation timing of a peak output signal in the pulse laser light detection device according to the present invention.

FIG. 3 is a block diagram illustrating a configuration of a conventional pulsed laser light detection device.

FIG. 4 is a diagram showing an output voltage waveform and a generation timing of a threshold signal in a conventional pulsed laser light detection device.

FIG. 5 is a diagram showing another output voltage waveform and a generation timing of a threshold signal in the conventional pulse laser light detection device.

[Explanation of symbols]

 1-1 to 1-n Optical system 2-1 to 2-n Photodetector 3-1 to 3-n Voltage conversion circuit 4-1 to 4-n Comparison circuit 5-1 to 5-n Peak time measurement circuit 6 Discrimination circuit 7 Display

Claims (3)

(57) [Claims] A plurality of light condensing means for converging the pulsed laser light from a predetermined direction, and a plurality of light detecting means provided corresponding to the plurality of light condensing means, respectively. In a pulse laser light detection device that detects output signals from the plurality of light detection means and determines direct light,
A plurality of peak time measuring means for receiving an output signal from the plurality of light detection means and transmitting a peak output signal when the plurality of output signals each reach a peak value,
A receiving unit that receives the plurality of peak output signals, determines a pulse laser beam having the fastest time to reach a peak among the plurality of measured values, and determines the determined pulse laser beam as direct light. A pulsed laser light detection device, characterized in that 2. The pulse laser light detecting device according to claim 1, wherein said plurality of peak time measuring means comprises a comparing circuit and a peak time measuring circuit, and said plurality of comparing circuits respectively correspond to said light detecting means. Receiving the output signal from the means, comparing the output levels of the plurality of output signals with a predetermined threshold, and transmitting a timing signal when the output level is equal to or higher than the predetermined threshold; The plurality of peak time measurement circuits respectively receive the output signal and the timing signal, and when the output signal reaches a peak value, respectively transmit a peak output signal to the determination unit. Detection device. 3. The pulse laser light detection device according to claim 1, further comprising a display unit for displaying a direction of the pulse laser light determined by said determination unit. .