JP3692495B2 - Laser sighting device and laser emission method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser light source device and a laser light emitting method, and more particularly, a laser light source device and a laser light emitting method capable of generating intermittent pulsed light having a predetermined blinking time and enhancing peak brightness by the Bartley effect. It is about.
[0002]
[Prior art]
Conventionally, there are various types of laser irradiation apparatuses for irradiating a target with laser light, and in recent years, their applications have spread and are rapidly spreading.
[0003]
In these laser irradiation apparatuses, generally continuous laser light has been adopted.
[0004]
[Problems to be solved by the invention]
However, the conventional laser irradiation apparatus has relatively few problems when irradiating an object at a short distance, but when irradiating an object at a long distance, the light diffuses and the irradiation light attenuates. There was a problem of doing.
[0005]
The attenuation of the irradiation light makes it difficult for the user to recognize himself / herself, and particularly in the daytime when the surroundings are bright.
[0006]
In order to solve the attenuation of the irradiated light, first, the output of the light source can be increased. However, there is a problem that the influence of the laser beam on the human body increases, the danger increases, and the power consumption also increases. .
[0007]
Further, the increase in the output of the laser light has a serious problem that it is accompanied by an increase in the number of protection facilities, resulting in an increase in cost and troublesome handling.
[0008]
[Means for Solving the Problems]
The present invention has been devised in view of the above problems, and the laser light source is an excitation type laser light source, and intermittent pulse light having a predetermined blinking time is emitted to the laser light source and the laser light source. The intermittent pulsed light is a flashing cycle that is slower than a normal flicker value of 40 to 50 Hz, and the flashing off time is after the light is incident on the human eye, A laser light source device having a turn-off time longer than 50 msec when the sensitivity of the human eye returns to the maximum sensitivity with respect to light, the turn-off time being approximately 2T, and the turn-on time being T is provided rotatably. It is characterized by irradiating a target with laser light.
[0009]
The present invention also relates to a timing circuit for forming a timing signal such that intermittent pulsed light having a predetermined blinking time is generated with respect to the excitation type laser light source. And a pumping laser for pumping the excitation type laser light source on the basis of the output signal, and can be configured to emit intermittent pulsed light.
[0013]
In the laser emission method of the present invention, the laser light source is an excitation type laser light source, and the laser light source is blinking whose cycle is slower than a normal flicker value of 40 Hz to 50 Hz. After the light is incident on the eye, the time when the human eye sensitivity returns to the maximum sensitivity again with respect to the light is a turn-off time longer than 50 msec. This turn-off time is approximately 2T, and the turn-on time is T. It is configured to emit light as intermittent pulse light having a long blinking time.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention configured as described above, the laser light source is an excitation type laser light source, and the driving means emits intermittent pulse light having a predetermined blinking time to the laser light source, This intermittent pulse light blinks with a period slower than the flicker value of 40 to 50 Hz of a normal person, and the blinking extinction time is such that after the light is incident on the human eye, the sensitivity of the human eye to the light again. The time to return to the maximum sensitivity is a turn-off time longer than 50 msec, and this turn-off time is approximately 2T. A laser light source device having a turn-on time T is provided rotatably, and the target is irradiated with laser light. It has become.
[0015]
Further, the laser light source of the present invention is an excitation laser light source, and the timing circuit forms a timing signal for generating an intermittent pulse light having a predetermined blinking time with respect to the excitation laser light source. Based on the output signal of the timing circuit, the pumping type laser light source can be pumped to emit intermittent pulse light.
[0019]
In the laser emission method of the present invention, the laser light source is an excitation type laser light source, and the laser light source is blinking whose cycle is slower than a normal flicker value of 40 Hz to 50 Hz. After the light is incident on the light, the human eye's sensitivity to the light again returns to the maximum sensitivity, which is a turn-off time longer than 50 msec. This turn-off time is approximately 2T, and the turn-on time is T. Light is emitted as intermittent pulse light having a blinking time.
[0020]
【principle】
[0021]
Here, the principle of the present invention will be described briefly.
[0022]
The human eye can recognize the light emission instantaneously when the light source emits light, but thereafter, the light recognition is diffusely lowered so as to feel afterglow. In general, a blinking light source is easier to recognize than a continuously emitting light source. This state is shown in FIG. 7, where the solid line is the laser light that is pulse-driven, and the dotted line is the response of the human eye to the light pulse.
[0023]
In other words, when the light source is turned off, the human eye returns to the maximum sensitivity again after a certain time.
[0024]
Therefore, in order to give a stimulus to the human eye with the maximum sensitivity, intermittent driving for emitting the next light pulse may be performed in a state where the sensitivity of the eye returns to the maximum sensitivity after a certain time.
[0025]
A normal person can recognize blinking at a boundary of about 40 to 50 Hz. It is necessary to make the flashing cycle slower than the flicker value.
[0026]
According to the experiment, it is found that the most recognizable blinking is 6 Hz to 15 Hz by the combination of the driving by the pulse and the blinking operation. Note that a phenomenon in which the brightness of the peak is emphasized and felt when the frequency of the flickering light is about 10 Hz is called a Bartley effect, and is also called a Brucke-Bartley effect.
[0027]
The Bartray effect is known to have the maximum effect when the ratio between the lighting time and the lighting time is 1: 1, and the human eye's visual sensitivity reaches the maximum value during the lighting time of 50 msec, and the light is turned off. It means that the visual sensitivity returns to the maximum sensitivity within a time of 50 msec. By setting the extinguishing time to 50 msec or more, stimulation by the next light pulse can be effectively applied to the human eye.
[0028]
Note that when the lighting time of the light source is increased, the visibility of the human eye decreases. In general, it is known that a peak occurs around 50 to 120 msec after light emission, and then gradually decreases and gradually approaches a certain value. By setting the light emission time to about 50 to 120 msec, the ratio between the visual sensitivity and the driving power of the light source can be made most favorable.
[0029]
【Example】
[0030]
Embodiments of the present invention will be described with reference to the drawings.
[0031]
"First Example"
[0032]
FIG. 1 shows an electrical configuration of the laser oscillation apparatus 1000 according to the first embodiment, and includes a timing circuit 100, a laser diode drive circuit 200, a laser light source 300, and a control unit 400.
[0033]
The timing circuit 100 controls and drives the laser diode drive circuit 200 to generate intermittent pulse light having a predetermined blinking time from the laser light source 300.
[0034]
The laser diode drive circuit 200 corresponds to drive means, and drives the laser light source 300 based on the control signal of the timing circuit 100.
[0035]
The laser light source 300 is a laser light source that generates intermittent pulsed light having a predetermined blinking time. The laser light source 300 according to the first embodiment is an excitation laser light source, and includes an excitation laser means 310 and an excitation laser 320 including an optical resonator. The excitation laser means 310 corresponds to a pumping laser.
[0036]
The excitation laser means 310 functions as a pump light generator, and the excitation laser 320 resonates the light by reciprocating the light between the dielectric reflection film and the output mirror and confining the light for a long time. Can be amplified.
[0037]
In addition, although the semiconductor laser is employ | adopted for the excitation laser means 310 of the 1st Example, any thing can be employ | adopted if it is an element which can inject | emits a laser beam.
[0038]
The laser light source 300 is not limited to the excitation laser, and any means can be adopted as long as it is a means capable of generating laser light.
[0039]
The control unit 400 controls the entire laser oscillation apparatus 1000 including the timing circuit 100, and includes an arithmetic processing unit including a CPU.
[0040]
In this embodiment configured as described above, as shown in FIG. 2, the laser light source 300 can generate a laser beam of 200 KHz and 3 mW. As for pulse light emission, as described in “Laser light source”, power saving can be achieved.
[0041]
As shown in FIG. 3, the timing circuit 100 is configured to drive the laser diode drive circuit 200 so that the light pulse emission time T is, for example, 30 ms, the extinguishing time is 2T, and one period is 3T. ing.
[0042]
That is, the light pulse emission time T is configured to be substantially coincident with the time when the brightness is felt most after the light enters the human eye, and the light-off time is the light incident on the human eye. Then, after the user feels brightness, the eye sensitivity is configured to substantially coincide with the time required for the eye sensitivity to return to the maximum sensitivity.
[0043]
Further, the turn-off time is set to about twice the light pulse emission time in order to further suppress the power consumption of the pumping laser for pumping the excitation laser light source. In this embodiment, the lighting time is 47 msec and the extinguishing time is 94 msec. However, the lighting time is not limited to this time and can be changed as appropriate.
[0044]
As a result, the human eye is irradiated with a pulse of laser light with the highest sensitivity, making visual recognition very easy. And although visual recognition is easy, an average output becomes about 1 mW and can further improve the safety | security with respect to a human body. Furthermore, the power consumption of the pumping laser for pumping the excitation type laser light source becomes one third, and the power consumption can be reduced.
[0045]
In the case of continuous-emitting laser light, if the output standard is 1 mW or less, regulations regarding safety equipment are relatively weak, but it is difficult to visually recognize in a bright place. On the other hand, if intermittent rectangular light emission is performed as shown in FIG. 3, if the light emission amount within a predetermined time is 1 mW or less, it can be used with relatively weak protection regulations against the human body, and it is bright. Visibility is improved even in places.
[0046]
As shown in FIG. 4, the timing circuit 100 is configured such that the light pulse emission time is T ′, the extinction time is 2T ′, and one cycle is 3T ′, and one cycle 3T ′ is 10 ms or less. In this case, the average output of the laser light is about 1 mW.
[0047]
However, when the period of intermittent rectangular light emission is short, it is visually recognized as an average as a whole, but when pulse light emission is performed, there is an effect that power saving can be achieved even if the visibility is the same.
[0048]
In addition, it is more effective if the pulse continuous drive, the intermittent pulse drive, and the intermittent pulse drive with a period of 10 mS or less are switched according to the needs of the work site.
[0049]
"Second Example"
[0050]
Next, a modification of the electrical configuration of the laser oscillation apparatus 1000 of the first embodiment will be described. FIG. 5 illustrates a second embodiment of the present embodiment and shows an electrical configuration of the laser oscillation device 2000. The timing circuit 100, the laser diode drive circuit 200, the laser light source 300, and the control are shown in FIG. Part 400.
[0051]
Whereas the laser light source 300 of the first embodiment employs an excitation laser, the second embodiment employs a normal laser diode for the laser light source 300 instead of the excitation laser. As the laser diode, any type of semiconductor laser can be used.
[0052]
In addition, since the effect | action of another structure, an effect, etc. are the same as that of 1st Example, description is abbreviate | omitted.
[0053]
“Third Example”
[0054]
FIG. 6 illustrates a third embodiment of the present embodiment and shows an electrical configuration of the laser oscillation device 3000. The timing circuit 100, the drive unit 250, the laser unit 350, and the control unit 400 are illustrated. And chopper means 500.
[0055]
In the third embodiment, laser pulse light is continuously generated from the laser unit 350 and converted into intermittent pulse light having a desired blinking time by the chopper means 500.
[0056]
The drive unit 250 drives the chopper means 500.
[0057]
The chopper means 500 can generate intermittent pulse light having a desired blinking time by intermittently interrupting the continuous pulse light from the laser unit 350.
[0058]
The chopper means 500 can use a mechanical shutter, a chopper device composed of AO (acousto-optic element), EO (electro-optic element), or the like.
[0059]
The timing circuit 100 determines the timing for operating the chopper means 500.
[0060]
The control unit 400 controls and drives the timing circuit 100 and operates the chopper means 500 via the drive unit 250.
[0061]
As in the first and second embodiments, the third embodiment configured as described above can generate intermittent pulsed light having a desired blinking time.
[0062]
The laser unit 350 may employ any type of laser light source.
[0063]
In addition, since the effect | action of another structure, an effect, etc. are the same as that of 1st Example, description is abbreviate | omitted.
[0064]
"About laser light source"
[0065]
Here, the laser light source 300 of the first embodiment will be described.
[0066]
8A, FIG. 8B, and FIG. 8C are schematic diagrams showing the gain switch, and FIG. 8A is a diagram showing the relationship between time and excitation intensity, and FIG. FIG. 8B is a diagram showing the relationship between time and light intensity, and FIG. 8C shows the relationship between time and inversion distribution.
[0067]
Observation of these figures shows that maximum light intensity occurs after a certain excitation time.
[0068]
Next, FIG. 9 shows the relationship between the inversion distribution and the light intensity separately. If continuous wave drive power is supplied to the semiconductor laser, the maximum light intensity is generated corresponding to the first pulse, and then the light intensity decreases and converges to a constant light intensity. It is the most efficient. Therefore, only the first pulse is used.
[0069]
Further, with reference to FIGS. 10A and 10B, a case where continuous pulse driving power is supplied to the semiconductor laser will be described.
[0070]
FIG. 10A shows a case where the period T of the continuous pulse supplied to the semiconductor laser has a relationship of τ _FL <T−τ. Here, τ _FL is the fluorescence lifetime, and τ is the pulse width.
[0071]
On the other hand, FIG. 10B shows a case where the period T of the continuous pulse supplied to the semiconductor laser has a relationship of τ _FL > T−τ.
[0072]
10B, by applying the next pulse to the semiconductor laser during τ _FL (fluorescence lifetime), a new inversion distribution is added to the remaining inversion distribution to effectively maximize the light intensity. It will be understood that only light having a can be generated continuously.
[0073]
Next, the relationship between the output of the semiconductor laser and the output when the nonlinear optical medium 400 is inserted will be described with reference to FIGS. 11 (a) to 11 (d).
[0074]
FIG. 11A shows the relationship between the consumption current of the semiconductor laser and the output of the semiconductor laser, and after the offset current has a linear relationship.
[0075]
FIG. 11B shows the relationship between the output of the semiconductor laser and the output of the fundamental wave in the optical resonator, and has a linear relationship after the offset.
[0076]
FIG. 11C shows the relationship between the fundamental wave output in the optical resonator and the second harmonic (SHG) output when a nonlinear optical medium is inserted, and the second harmonic (SHG). It is understood that the output is proportional to the square of the output of the fundamental wave in the optical resonator.
[0077]
Therefore, the relationship between the consumption current of the semiconductor laser and the second harmonic (SHG) output is proportional to the square as shown in FIG.
[0078]
Therefore, if a nonlinear optical medium is inserted into the optical resonator and the laser drive means drives the semiconductor laser of the laser light source 100 so that the next drive pulse is applied within τ _FL (fluorescence lifetime), As shown in FIG. 12, the laser can be oscillated with high efficiency.
[0079]
That is, FIG. 12 shows that when the semiconductor laser of the laser light source 100 is driven by the pulse width τ, the pulse peak current I _P , and the pulse period T, laser light having an optical pulse width τ ′ optical pulse peak output P ^P _SH is generated. Become.
[0080]
When the laser driving means continuously drives the laser light source 300 (provided that the same continuous output P ^cw _SH as the average pulse output P ^av _SH is generated), the semiconductor can be obtained if the continuous operating current is I _CW. Since the relationship between the laser current consumption and the second harmonic (SHG) output is proportional to the square, only the laser light of the continuous light output P ^CW _SH that is smaller than the optical pulse peak output P ^P _SH is generated.
[0081]
Further, in the case of pulse driving, since the operation is intermittent, the average value is compared with the continuous operation. In the case of pulse driving, the average pulse current is I _av , and the continuous operation current is smaller than I _CW .
[0082]
Therefore, if a semiconductor laser is used in addition to the pump laser, the current of I _CW -I _av can be saved when generating a laser beam having the same output as the continuous wave by pulse driving. effective.
[0083]
Application example
[0084]
An application example of the first to third embodiments will be described. This application example is an example applied to a laser aiming device.
[0085]
As shown in FIGS. 13 and 15, the laser sighting device includes a frame 1, an elevation frame 3 that is pivotally mounted around a horizontal elevation shaft 2 formed near the front end of the frame 1, and the elevation frame 3 is composed of a laser oscillation device 5 formed so as to be swingable about a swing shaft 4 attached in a vertical direction with respect to 3.
[0086]
A horizontal auxiliary frame 6 is formed on the lower side of the lifting frame 3 so as to face rearward, and a horizontal pin 7 is formed on the horizontal auxiliary frame 6. The pin 7 is connected to the frame 1 via a spring 8 and urges the lifting frame 3 in the clockwise direction by the elastic restoring force of the spring 8.
[0087]
A lifting screw 10 is erected in a direction substantially orthogonal to the pin 7, and a nut 11 screwed to the lifting screw 10 and a fixed pin 12 protruding from the nut 11 are engaged. The raising / lowering screw 10 is connected to the output shaft of the raising / lowering motor 9 placed on the frame 1, and the inclination of the raising / lowering frame 3 can be varied by the driving force of the raising / lowering motor 9.
[0088]
As shown in FIG. 15, a vertical auxiliary frame 13 is formed on the side of the lifting frame 3, and a swing motor 15 is attached to the vertical auxiliary frame 13 via a gear box 14. A guide shaft 16 and a swing screw 17 are extended in a horizontal direction from the gear box 14, and the swing screw 17 is connected to an output shaft of the swing motor 15. A nut block 18 screwed to the swing screw 17 is slidably fitted to the guide shaft 16.
[0089]
A horizontal protruding pin 19 is attached to the rear end portion of the laser oscillation device 5 in the horizontal direction, and the horizontal protruding pin 19 is engaged with an engagement pin 20 formed on the nut block 18. An elastic spring 21 is inserted between the horizontal protruding pin 19 and the vertical auxiliary frame 13, and the elastic oscillation force of the elastic spring 21 causes the laser oscillation device 5 to move in the horizontal direction, that is, to the right in FIG. Is energized.
[0090]
The laser sighting device configured as described above can be rotated in two orthogonal directions by driving the elevation motor 9 and the swing motor 15.
[0091]
Further, FIG. 16 shows an example used for pipe installation work, in which the target 3000 is collimated using the laser aiming device 2000 provided with the laser oscillation device 1000 of the present embodiment.
[0092]
Even in a bright spot where sunlight hits, the target 3000 can be easily irradiated.
[0093]
【effect】
In the present invention configured as described above, the laser light source is an excitation laser light source,
It consists of a laser light source and a driving means for driving the laser light source so that intermittent pulse light having a predetermined blinking time is emitted. This intermittent pulse light is based on a normal flicker value of 40 to 50 Hz. The blinking extinguishing time, which is a slow blinking period, is an extinguishing time longer than 50 msec when the human eye sensitivity returns to the maximum sensitivity again after the light enters the human eye. The laser light source device having a turn-off time of about 2T and a turn-on time of T is provided so as to be rotatable and irradiates the target with laser light. And has an effect of improving visibility even if the surroundings are bright.
[0094]
[Brief description of the drawings]
FIG. 1 is a diagram showing a laser oscillation apparatus 1000 according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a laser oscillation state.
FIG. 3 is a diagram illustrating a laser oscillation state.
FIG. 4 is a diagram illustrating a laser oscillation state.
FIG. 5 is a diagram illustrating a laser oscillation device 2000 according to a second embodiment.
FIG. 6 is a diagram showing a laser oscillation device 3000 according to a third embodiment.
FIG. 7 is a diagram showing the principle of the present invention.
FIG. 8A is a schematic diagram showing a gain switch, and shows the relationship between time and excitation intensity.
FIG. 8B is a schematic diagram showing a gain switch, showing the relationship between time and light intensity.
FIG. 8C is a schematic diagram showing a gain switch, showing the relationship between time and inversion distribution.
FIG. 9 is a diagram showing a relationship between inversion distribution and light intensity.
FIG. 10A is a diagram for explaining a case where the period T of the continuous pulse supplied to the semiconductor laser has a relationship of τ _FL <T−τ.
FIG. 10B is a diagram for explaining a case where the period T of the continuous pulse supplied to the semiconductor laser has a relationship of τ _FL > T−τ.
FIG. 11A is a diagram showing the relationship between the consumption current of the semiconductor laser and the output of the semiconductor laser.
FIG. 11B is a diagram showing the relationship between the output of the semiconductor laser and the output of the fundamental wave in the optical resonator.
FIG. 11C is a diagram showing the relationship between the fundamental wave output in the optical resonator and the second harmonic (SHG) output when the nonlinear optical medium 400 is inserted.
FIG. 11D is a diagram showing the relationship between the consumption current of the semiconductor laser and the second harmonic (SHG) output.
FIG. 12 is a diagram comparing the case where the laser oscillation apparatus 1000 is continuously driven and the case where the laser is driven according to the present invention.
FIG. 13 is a diagram illustrating an application example.
FIG. 14 is a diagram illustrating an application example.
FIG. 15 is a diagram illustrating an application example.
FIG. 16 is a diagram illustrating an application example.
[Explanation of symbols]
1000 Laser oscillation device 2000 of the first embodiment Laser oscillation device 3000 of the second embodiment Laser oscillation device 100 of the third embodiment Timing circuit 200 Laser diode drive circuit 250 Drive unit 300 Laser light source 310 Excitation laser means 320 Excitation laser 350 Laser unit 400 Control unit 500 Chopper means 1 Frame 2 Elevating shaft 3 Elevating frame 4 Oscillating shaft 5 Laser oscillation device 6 Horizontal auxiliary frame 7 Pin 8 Spring 9 Elevating motor 10 Elevating screw 11 Nut 12 Fixed pin 13 Vertical auxiliary frame 14 Gearbox 15 Oscillating motor 16 Guide shaft 17 Oscillating screw 18 Nut block 19 Horizontal protruding pin 20 Engaging pin 21 Elastic spring

Claims (3)

The laser light source is an excitation type laser light source, and comprises a laser light source and a driving means for driving the laser light source so that intermittent pulse light having a predetermined blinking time is emitted. Is blinking with a period slower than the flicker value 40 to 50 Hz of a normal person, and the blinking extinction time is such that after the light is incident on the human eye, the sensitivity of the human eye to the light again becomes the maximum sensitivity. The return time is longer than 50 msec, the turn-off time is approximately 2T, a laser light source device having a turn-on time T is provided rotatably, and the object is irradiated with laser light. Laser sighting device. The laser light source is an excitation type laser light source, and a timing circuit for forming a timing signal such that intermittent pulse light having a predetermined blinking time is generated to the excitation type laser light source, and an output signal of the timing circuit The laser sighting device according to claim 1, further comprising: a pumping laser for pumping the excitation laser light source, and emitting intermittent pulse light. The laser light source is an excitation type laser light source, and this laser light source is blinking with a period slower than the normal flicker value of 40 Hz to 50 Hz, and the blinking extinction time is after light enters the human eye, Intermittent pulse light having a turn-off time longer than 50 msec when the human eye sensitivity returns to the maximum sensitivity with respect to the light, the turn-off time being approximately 2T, and a blinking time such that the turn-on time is T As a laser emission method.

Images