JP2016021506A - Laser light source controller and laser pointer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a general-purpose laser light source controller and a laser pointer which are applicable to various kinds of laser light sources different in activation voltage.SOLUTION: A laser light source controller 100 comprises: a light-receiving element 1 which detects a light quantity of laser light emitted by a laser light source 200, and outputs a current according to the light quantity thus detected; a control part 2 which controls a current for driving the laser light source according to an output current of the light-receiving element so that the output current of the light-receiving element is fixed; and a power-source part 3 which supplies the laser light source with a first drive voltage V1 and supplies each of the light-receiving element and the control part with a second drive voltage V2. The power-source part includes a constant-voltage power source 31 which outputs a fixed voltage and a voltage-changing part 32 which changes and outputs an output voltage of the constant-voltage power source, and selectively supplies, as each of the first and second drive voltages, one of an output voltage Vin of the constant-voltage power source and an output voltage Vout of the voltage-changing part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser light source control device for stabilizing the amount of laser light emitted from a laser light source, and a laser pointer provided with the laser light source control device. In particular, the present invention has versatility applicable to various laser light sources having different drive voltages, and can stably reduce the power consumption of the laser light source, and the laser light source control device. The present invention relates to a laser pointer provided.

Conventionally, in various laser devices such as a laser pointer, a laser light source control device called a so-called APC (Auto Power Control) circuit has been used to stabilize the amount of laser light emitted from a laser light source such as a semiconductor laser. (For example, refer to Patent Document 1).
This laser light source control device generally detects the amount of laser light emitted from a laser light source, outputs a current corresponding to the detected light amount, and makes the output current of the light receiving element constant. A control unit that controls the drive current of the laser light source in accordance with the output current of the light receiving element (that is, the amount of light detected by the light receiving element is constant), and a drive voltage applied to each of the laser light source, the light receiving element, and the control unit And a power supply unit for supplying power.

  Many of the laser pointers use a dry battery as a power source for the laser light source control device because it is easy to carry. For this reason, the drive voltages supplied to each of the laser light source, the light receiving element, and the control unit are often all set to the same value (power supply voltage of the dry cell).

However, as described above, there is a laser pointer using a laser light source that can be driven even with a small drive voltage that is the same as the drive voltage required for the light receiving element and the control unit. Laser pointers using laser light sources (for example, a green semiconductor laser and a blue semiconductor laser) that require a large drive voltage that cannot be driven with the same drive voltage have appeared.
For this reason, the configuration of the laser light source control device must be changed according to the drive voltage of the laser light source to be used, that is, a new laser light source control device needs to be prepared. Accordingly, there is a problem that it takes time to verify the operation of the new laser light source control device, and causes a rise in development cost and manufacturing cost of the laser pointer.

In addition, as described above, a dry battery is used as the power source of the laser light source control device in many laser pointers, so that the consumption of the laser light source is reduced for the purpose of extending the life of the dry battery and reducing the replacement frequency. It is desirable to reduce power.
As a method for reducing the power consumption of a laser light source, for example, Patent Document 2 proposes a method in which a drive signal of a laser light source (semiconductor laser) is converted to a pulse signal (paragraphs 0010 and 0011 of Patent Document 2). .

  However, in the method described in Patent Document 2, no consideration is given to the case where an abnormality occurs in the pulse signal. For this reason, for example, when the pulse signal becomes abnormal for some reason and becomes a constant drive signal (for example, a drive signal that remains high), the drive current of the laser light source becomes a constant current ( For example, when the peak current remains, there is a problem that the power consumption of the laser light source is not reduced.

JP 2012-38789 A JP 2008-84931 A

  The present invention has been made to solve the above-described problems of the prior art, and provides a laser light source control device having versatility applicable to various laser light sources having different driving voltages. (First problem). It is another object of the present invention to provide a laser light source control device that can stably reduce the power consumption of a laser light source (second problem). It is another object of the present invention to provide a laser pointer including these laser light source control devices (third problem).

  In order to solve the first problem, the present invention provides, as a first means, a laser light source control device for stabilizing the amount of laser light emitted from a laser light source, the laser emitted from the laser light source. A light receiving element that detects a light amount of light and outputs a current corresponding to the detected light amount, and a driving current of the laser light source according to an output current of the light receiving element so that an output current of the light receiving element is constant And a power supply unit that supplies a first drive voltage to the laser light source and supplies a second drive voltage to each of the light receiving element and the control unit, and the power supply unit supplies a constant voltage. A constant voltage power source for outputting, and a voltage changing unit for changing and outputting the output voltage of the constant voltage power source, wherein the power source unit outputs the output voltage of the constant voltage power source and the voltage as the first drive voltage. Change part output One of output voltages is selectively supplied to the laser light source, and the output voltage of the constant voltage power supply is supplied to each of the light receiving element and the control unit as the second drive voltage, or A laser light source control device, wherein either one of the output voltage of the constant voltage power supply and the output voltage of the voltage changing unit is selectably supplied to the light receiving element and the control unit. provide.

The power supply unit included in the laser light source control device according to the first means of the present invention supplies the first drive voltage to the laser light source and supplies the second drive voltage to each of the light receiving element and the control unit. The power supply unit includes a constant voltage power source that outputs a constant voltage, and a voltage change unit that changes and outputs the output voltage of the constant voltage power source. Then, either the output voltage of the constant voltage power supply or the output voltage of the voltage changing unit is selectively supplied to the laser light source as the first drive voltage, and the output of the constant voltage power supply is used as the second drive voltage. A voltage is supplied to each of the light receiving element and the control unit (only the output voltage of the constant voltage power supply is supplied to each of the light receiving element and the control unit fixedly), or the output voltage of the constant voltage power supply and the voltage changing unit Any one of the output voltages is supplied to each of the light receiving element and the control unit in a selectable manner.
That is, when the power supply unit is configured to supply the output voltage of the constant voltage power supply to each of the light receiving element and the control unit as the second drive voltage, in the laser light source control device according to the first means of the present invention. The following combination patterns (1) and (2) can be selected as the first driving voltage supplied to the laser light source and the second driving voltage supplied to each of the light receiving element and the control unit.
(1) First drive voltage: output voltage of constant voltage power supply, second drive voltage: output voltage of constant voltage power supply (2) First drive voltage: output voltage of voltage changing unit, second drive voltage: constant voltage power supply Output voltage Further, the power supply unit supplies, as the second drive voltage, one of the output voltage of the constant voltage power supply and the output voltage of the voltage changing unit to be selectably supplied to each of the light receiving element and the control unit. In this case, the following combination patterns (3) and (4) can be selected in addition to the combination patterns (1) and (2).
(3) First drive voltage: output voltage of constant voltage power supply, second drive voltage: output voltage of voltage changing unit (4) first drive voltage: output voltage of voltage changing unit, second drive voltage: of voltage changing unit Therefore, in the past, only the configuration corresponding to the combination pattern (1) (the drive voltage supplied to each of the laser light source, the light receiving element, and the control unit is the same value, which is all equal to the power supply voltage of a dry cell, etc.) can be selected. However, the combination pattern (2) can be selected, or the combination patterns (2) to (4) can be selected. For example, when the laser light source control device according to the first means of the present invention is applied to a laser pointer, it is conceivable that the constant voltage power source is a dry battery and the voltage changing unit is constituted by a booster circuit. In the case of this configuration, when applied to a laser light source (for example, a red semiconductor laser or a green DPSS laser) that can be driven with the same drive voltage as that of the light receiving element and the control unit, the combination pattern of (1) above. And is applied to a laser light source (for example, a green semiconductor laser) that requires a large driving voltage that cannot be driven with the same driving voltage as that of the light receiving element and the control unit. A combination pattern may be selected.
As described above, according to the first means of the present invention, it is possible to provide a laser light source control device having versatility applicable to various laser light sources having different driving voltages.

  Preferably, in the first means of the present invention, the control unit includes a pulse oscillation unit that outputs a pulse voltage, and an abnormality detection unit that detects an abnormality of the pulse voltage output from the pulse oscillation unit, If no abnormality of the pulse voltage is detected by the abnormality detection unit, a pulse having a current value corresponding to the output current of the light receiving element based on the output current of the light receiving element and the pulse voltage output from the pulse oscillating unit The drive current of the laser light source is controlled so as to become current, and when the abnormality of the pulse voltage is detected by the abnormality detection unit, the drive current of the laser light source is stopped.

According to such a preferable configuration, in a normal case (when an abnormality of the pulse voltage is not detected by the abnormality detection unit), the control unit is configured so that the laser light source has a pulse current having a current value corresponding to the output current of the light receiving element. To control the drive current. For this reason, it is possible to reduce the power consumption of the laser light source as compared with the case where the drive current is a constant current (for example, when the drive current remains the peak current).
On the other hand, when the abnormality of the pulse voltage is detected by the abnormality detection unit, the control unit stops the drive current of the laser light source. For example, as a result of an abnormality in which a constant voltage (for example, a high voltage) is output from the pulse oscillating unit instead of a pulse voltage due to a failure of the pulse oscillating unit, as shown in FIG. It is conceivable that the current becomes a constant current (for example, the peak current remains). In this case, the power consumption of the laser light source is not reduced. However, according to the above preferred configuration, when the abnormality of the pulse voltage is detected by the abnormality detection unit, the control unit stops the driving current of the laser light source, so that the driving current of the laser light source continues to be supplied with a constant current. Therefore, power consumption can be reduced.
That is, according to the preferable configuration, in addition to the first problem, the second problem can be solved.

  In order to solve the second problem, the present invention provides, as a second means, a laser light source control device for stabilizing the amount of laser light emitted from a laser light source, which is emitted from the laser light source. A light receiving element that detects a light amount of the laser light and outputs a current corresponding to the detected light amount; and an output current of the laser light source according to an output current of the light receiving element so that an output current of the light receiving element is constant. A control unit that controls a drive current; and a power source unit that supplies a drive voltage to each of the laser light source, the light receiving element, and the control unit, the control unit including a pulse oscillation unit that outputs a pulse voltage; An abnormality detection unit that detects an abnormality of the pulse voltage output from the pulse oscillation unit, and when no abnormality of the pulse voltage is detected by the abnormality detection unit, the output current of the light receiving element and the voltage are detected. Based on the pulse voltage output from the oscillation unit, the drive current of the laser light source is controlled so that the pulse current has a current value corresponding to the output current of the light receiving element, and the abnormality detection unit When a laser beam is detected, a laser light source control device is provided that stops the drive current of the laser light source.

In the laser light source control device according to the second means of the present invention, in the normal case (when the abnormality of the pulse voltage is not detected by the abnormality detection unit), the control unit has a pulse having a current value corresponding to the output current of the light receiving element. The drive current of the laser light source is controlled so as to be current. For this reason, it is possible to reduce the power consumption of the laser light source as compared with the case where the drive current is a constant current (for example, when the drive current remains the peak current).
On the other hand, when the abnormality of the pulse voltage is detected by the abnormality detection unit, the control unit stops the drive current of the laser light source. For example, as a result of an abnormality in which a constant voltage (for example, a high voltage) is output from the pulse oscillating unit instead of a pulse voltage due to a failure of the pulse oscillating unit, as shown in FIG. It is conceivable that the current becomes a constant current (for example, the peak current remains). In this case, the power consumption of the laser light source is not reduced. However, according to the laser light source control device according to the second means of the present invention, when the abnormality of the pulse voltage is detected by the abnormality detection unit, the control unit stops the drive current of the laser light source. It is possible to reduce power consumption without continuing to be energized with a constant current.
As described above, according to the second means of the present invention, it is possible to provide a laser light source control device that can stably reduce the power consumption of a laser light source.

The laser light source control device described above is effective for use as a laser pointer.
That is, in order to solve the third problem, the present invention is also provided as a laser pointer characterized by including, as a third means, a laser light source and any one of the laser light source control devices described above. .

  According to the present invention, a laser light source control device having versatility applicable to various laser light sources having different driving voltages and capable of stably reducing the power consumption of the laser light source, and the laser light source control device are provided. A laser pointer can be provided.

FIG. 1 is a block diagram showing a schematic configuration of a laser pointer to which a laser light source control device according to a first embodiment of the present invention is applied. FIG. 2 is a block diagram showing a schematic configuration of a laser pointer to which the laser light source control device according to the second embodiment of the present invention is applied. FIG. 3 is a block diagram illustrating a specific configuration example of the intermediate voltage generation unit illustrated in FIG. 2. FIG. 4 is an explanatory diagram for explaining the operation of detecting an abnormality by the abnormality detection unit shown in FIG. FIG. 5 is a block diagram showing a schematic configuration of a laser pointer to which the laser light source control device according to the third embodiment of the present invention is applied. FIG. 6 is an explanatory diagram illustrating an example of an abnormality that occurs in the drive current of a laser light source that is pulse-driven.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings as appropriate.

<First Embodiment>
FIG. 1 is a block diagram showing a schematic configuration of a laser pointer to which a laser light source control device according to a first embodiment of the present invention is applied.
As shown in FIG. 1, the laser pointer according to the present embodiment includes a laser light source 200 and a laser light source control device 100.

  As the laser light source 200, a semiconductor laser, a semiconductor laser excitation solid-state laser (DPSS laser), or the like can be used.

  The laser light source control device 100 according to the present embodiment is a device for stabilizing the amount of laser light emitted from the laser light source 200, and includes a light receiving element 1, a control unit 2, and a power supply unit 3.

  The light receiving element 1 detects the amount of laser light emitted from the laser light source 200 and outputs a current corresponding to the detected amount of light. For example, a photodiode is used. The amount of light detected by the light receiving element 1 does not have to be the amount of all the laser light emitted from the laser light source 200. In general, a part of the laser light emitted from the laser light source 200 is obtained by a beam splitter or the like. The light is branched and the light amount of the branched laser light is detected by the light receiving element 1.

The controller 2 drives the laser light source 200 according to the output current of the light receiving element 1 so that the output current of the light receiving element 1 is constant (that is, the amount of light detected by the light receiving element 1 is constant). To control. The control unit 2 of this embodiment includes a control unit main body 21 and a transistor (bipolar transistor) 22.
The control unit main body 21 generates a voltage corresponding to the output current of the light receiving element 1 and outputs it to the base of the transistor 22. Specifically, for example, when the output current of the light receiving element 1 is smaller than a predetermined reference (when the amount of light detected by the light receiving element 1 is less than the target), the amount corresponding to the difference between the reference and the output current Just increase the voltage to be generated and output. Conversely, when the output current of the light receiving element 1 is larger than the reference (when the amount of light detected by the light receiving element 1 is larger than the target), a voltage to be generated by an amount corresponding to the difference between the reference and the output current. Reduce the output. A base current corresponding to the output voltage of the control unit main body 21 flows through the base of the transistor 22, and the drive current of the laser light source 200 is controlled according to this base current. That is, if the output voltage of the control unit main body 21 is large, the base current of the transistor 22 also increases, and the drive current of the laser light source 200 increases accordingly. On the other hand, if the output voltage of the control unit main body 21 is small, the base current of the transistor 22 is also small, and the drive current of the laser light source 200 is accordingly small.
As described above, the control unit 2 changes the drive current of the laser light source 200 in accordance with the output current of the light receiving element 1 so that the output current of the light receiving element 1 is constant (equal to a predetermined reference). Control.

The power supply unit 3 supplies the first drive voltage V1 to the laser light source 200, and supplies the second drive voltage V2 to each of the light receiving element 1 and the control unit 2 (control unit main body 21).
Specifically, the power supply unit 3 includes a constant voltage power supply 31 that outputs a constant voltage Vin, and a voltage change unit 32 that changes the output voltage Vin of the constant voltage power supply 31 and outputs a voltage Vout. A dry battery is used as the constant voltage power source 31 of the present embodiment. In addition, a booster circuit is used as the voltage changing unit 32 of the present embodiment. The boost ratio (Vout / Vin) of the booster circuit can be set by appropriately adjusting the impedance of passive elements such as resistors, capacitors, and coils provided in the booster circuit.
In this embodiment, a dry battery is used as the constant voltage power supply 31, but the present invention is not limited to this, and various power supplies can be used as long as a constant voltage is output. In the present embodiment, a booster circuit is used as the voltage changing unit 32. However, the present invention is not limited to this, and a step-down circuit can also be used.

Then, the power supply unit 3 supplies the laser light source 200 with one of the output voltage Vin of the constant voltage power supply 31 and the output voltage Vout of the voltage changing unit 32 so as to be selectable as the first drive voltage V1. As the second drive voltage V2, either one of the output voltage Vin of the constant voltage power supply 31 and the output voltage Vout of the voltage changing unit 32 can be selected. The light receiving element 1 and the control unit 2 (control unit main body 21). It is comprised so that it may supply to each.
Specifically, the power supply unit 3 of this embodiment includes a switch 33 and a switch 34. The switch 33 includes a first terminal to which the output voltage Vin of the constant voltage power supply 31 is supplied, a second terminal to which the output voltage Vout of the voltage changing unit 32 is supplied, and a third terminal connected to the laser light source 200. Have. When the connection of the switch 33 is switched so that the first terminal and the third terminal become conductive, the output voltage Vin of the constant voltage power supply 31 is supplied to the laser light source 200. On the other hand, when the connection of the switch 33 is switched so that the second terminal and the third terminal are conductive, the output voltage Vout of the voltage changing unit 32 is supplied to the laser light source 200. In the state shown in FIG. 1, the second terminal and the third terminal of the switch 33 are conductive, and the laser light source 200 is supplied with the output voltage Vout of the voltage changing unit 32 as the first drive voltage V1.
The switch 34 includes a first terminal to which the output voltage Vin of the constant voltage power supply 31 is supplied, a second terminal to which the output voltage Vout of the voltage changing unit 32 is supplied, the light receiving element 1 and the control unit 2 (the control unit main body 21). And a third terminal connected to both sides. When the connection of the switch 34 is switched so that the first terminal and the third terminal are conductive, the output voltage Vin of the constant voltage power supply 31 is supplied to each of the light receiving element 1 and the control unit 2 (control unit main body 21). The On the other hand, when the connection of the switch 34 is switched so that the second terminal and the third terminal are conductive, the output voltage Vout of the voltage changing unit 32 is applied to each of the light receiving element 1 and the control unit 2 (control unit main body 21). Supplied. In the state shown in FIG. 1, the first terminal and the third terminal of the switch 34 are electrically connected, and the light receiving element 1 and the control unit 2 (control unit main body 21) have a constant value as the second drive voltage V <b> 2. The output voltage Vin of the voltage power supply 31 is supplied.

  For example, when two dry batteries are used as the constant voltage power supply 31 included in the power supply unit 3, the output voltage Vin of the constant voltage power supply 31 is 3V. When the boost ratio of the voltage changing unit (boost circuit) 32 included in the power supply unit 3 is set to 2, the output voltage Vout of the voltage changing unit 32 is 6V. At this time, when a red semiconductor laser or a green DPSS laser is used as the laser light source 200, the connection of the switch 33 is switched so that the first terminal and the third terminal of the switch 33 are electrically connected, and the first terminal of the switch 34 is switched. By switching the connection of the switch 34 so that the third terminal is electrically connected to the third terminal, the output voltage Vin () of the constant voltage power supply 31 can be applied to any of the laser light source 200, the light receiving element 1, and the control unit 2 (control unit main body 21). 3V) is supplied, and the laser light source 200, the light receiving element 1, and the control unit 2 can be driven without any problem. When a blue semiconductor laser or a green semiconductor laser that requires a large driving voltage is used as the laser light source 200, the connection of the switch 33 is switched so that the second terminal and the third terminal of the switch 33 are conductive. Thus, the laser light source 200 is supplied with the output voltage Vout (6 V) of the voltage changing unit 32. On the other hand, by switching the connection of the switch 34 so that the first terminal and the third terminal of the switch 34 become conductive, the light receiving element 1 and the control unit 2 (control unit main body 21) have a constant voltage power supply 31. An output voltage Vin (3 V) is supplied. Thereby, the laser light source 200, the light receiving element 1, and the control part 2 can be driven without a problem.

  As described above, the laser light source control apparatus 100 according to the first embodiment of the present invention is applied to various laser light sources 200 having different driving voltages by simply switching the connection of the switch 33 and the connection of the switch 34. Has versatility possible.

  In the present embodiment, the power supply unit 3 includes the switch 34, and by switching the connection of the switch 34, one of the output voltage Vin of the constant voltage power supply 31 and the output voltage Vout of the voltage changing unit 32 is output. The configuration in which the voltage is selectably supplied to each of the light receiving element 1 and the control unit 2 (control unit main body 21) has been described. However, the present invention is not limited to this, and only the output voltage Vin of the constant voltage power supply 31 may be fixedly supplied to each of the light receiving element 1 and the control unit 2 (control unit main body 21). It is.

Second Embodiment
FIG. 2 is a block diagram showing a schematic configuration of a laser pointer to which the laser light source control device according to the second embodiment of the present invention is applied.
As shown in FIG. 2, the laser pointer according to the present embodiment also includes a laser light source 200 and a laser light source control device 100A. However, the configuration of the laser light source control device 100A is different from the laser light source control device 100 according to the first embodiment.
Hereinafter, in the laser light source control device 100A according to the present embodiment, the same components as those in the laser light source control device 100 according to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate. A different part from embodiment is demonstrated.

  The laser light source control device 100A according to the present embodiment is a device for stabilizing the amount of laser light emitted from the laser light source 200, and includes a light receiving element 1, a control unit 2A, and a power supply unit 3. The light receiving element 1 and the power supply unit 3 have the same configuration as that of the first embodiment, and only the control unit 2A is different from the control unit 2 of the first embodiment.

As in the control unit 2 of the first embodiment, the control unit 2A of this embodiment is configured so that the output current of the light receiving element 1 is constant (that is, the amount of light detected by the light receiving element 1 is constant). The drive current of the laser light source 200 is controlled according to the output current of the light receiving element 1, and includes a control unit main body 21 and a transistor (bipolar transistor) 22.
Unlike the control unit 2 of the first embodiment, the control unit 2A of the present embodiment is a pulse oscillation unit 23 that outputs a pulse voltage, and an abnormality detection unit 24 that detects an abnormality of the pulse voltage output from the pulse oscillation unit 23. It comprises. In addition, the control unit 2A of the present embodiment includes a transistor (MOS transistor) 25.

As shown in FIG. 2, the pulse voltage Va having a constant cycle output from the pulse oscillating unit 23 is input to the control unit main body 21. As a result, the control unit main body 21 generates a pulse voltage (pulse period is the same as the pulse voltage Va) having a voltage value (peak voltage value) corresponding to the output current of the light receiving element 1. Then, as described later, when the abnormality of the pulse voltage is not detected by the abnormality detection unit 24, the control unit main body 21 outputs the generated pulse voltage to the base of the transistor 22. That is, unlike the control unit main body 21 of the first embodiment in which only the output current (voltage) of the light receiving element 1 is input, the control unit main body 21 of the present embodiment includes the output current (voltage) of the light receiving element 1. When the pulse voltage Va output from the pulse oscillating unit 23 is input, a pulse voltage is generated instead of a constant voltage and is output to the base of the transistor 22. Accordingly, the base current becomes a pulse current, and accordingly, the drive current of the laser light source 200 also becomes a pulse current. The drive current (pulse current) of the laser light source 200 has a current value (peak current value) corresponding to the output current of the light receiving element 1.
As described above, when the abnormality detection unit 24 does not detect the abnormality of the pulse voltage Va, the control unit 2A of the present embodiment uses the output current of the light receiving element 1 and the pulse voltage Va output from the pulse oscillation unit 23. Based on this, the drive current of the laser light source 200 is controlled so that the pulse current has a current value (peak current value) corresponding to the output current of the light receiving element 1.

On the other hand, the control unit 2A of the present embodiment stops the drive current of the laser light source 200 when the abnormality detection unit 24 detects an abnormality in the pulse voltage.
Hereinafter, this point will be specifically described.
The abnormality detection unit 24 of this embodiment includes an intermediate voltage generation unit 241 and a comparator 242. The intermediate voltage generation unit 241 generates a voltage Vb having an intermediate voltage value between High (peak voltage value Vdd) and Low (GND) of the pulse voltage Va output from the pulse oscillation unit 23, and the comparator 242 Output to. The comparator 242 compares the output voltage Vb of the intermediate voltage generator 241 with the reference voltage Vref. When the output voltage Vb ≦ reference voltage Vref, the comparator 242 is Low (GND), and when the output voltage Vb> reference voltage Vref, the comparator 242 is High. A voltage Vc that becomes (voltage value Vdd) is output to the transistor 25.

FIG. 3 is a block diagram illustrating a specific configuration example of the intermediate voltage generation unit 241. As shown in FIG. 3, the intermediate voltage generation unit 241 can be configured by an integration circuit including a resistor and a capacitor, for example.
FIG. 4 is an explanatory diagram for explaining the operation of detecting an abnormality by the abnormality detection unit 24. 4A shows an example of the pulse voltage Va output from the pulse oscillating unit 23, FIG. 4B shows an example of the voltage Vb output from the intermediate voltage generating unit 241, and FIG. 4C shows the comparator 242. An example of the voltage Vc output from the output is shown.
When the pulse voltage Va output from the pulse oscillating unit 23 and input to the intermediate voltage generating unit 241 is a pulse voltage having a normal constant cycle, as shown in the first half of the graph shown in FIG. The voltage Vb output from the voltage generator 241 has an intermediate voltage value between the amplitude value Vdd and GND of the pulse voltage Va.

  However, when an abnormality occurs in the pulse voltage Va output from the pulse oscillating unit 23, the voltage Vb output from the intermediate voltage generating unit 241 changes greatly. In the example shown in FIG. 4A, an abnormality occurs in which the pulse voltage Va remains High (the peak voltage value Vdd remains), and as a result, the voltage Vb reaches Vdd as shown in FIG. 4B. It has increased. As shown in FIG. 4B, when the voltage Vb increases and the output voltage Vb> the reference voltage Vref, the voltage Vc output from the comparator 242 is high as shown in FIG. 4C. (Voltage value Vdd). In other words, when the abnormality detection unit 24 detects an abnormality in the pulse voltage Va, the abnormality detection unit 24 outputs a voltage Vc of High (voltage value Vdd). The reference voltage Vref may be set to a value larger than the voltage Vb output when the pulse voltage Va is normal and smaller than the voltage Vdd.

When the abnormality of the pulse voltage Va is detected by the abnormality detection unit 24 and the voltage Vc output from the abnormality detection unit 24 becomes High, the transistor 25 is turned on, so that the connection point with the output terminal of the control unit main body 21 is established. The potential of P (see FIG. 2) falls to GND. As a result, the base current of the transistor 22 stops flowing, and the drive current of the laser light source 200 is stopped.
On the other hand, when the abnormality of the pulse voltage Va is not detected by the abnormality detection unit 24, the voltage Vc output from the abnormality detection unit 24 is Low (GND), and the transistor 25 is not conductive. The generated pulse voltage is output to the base of the transistor 22. Thus, as described above, based on the output current of the light receiving element 1 and the pulse voltage Va output from the pulse oscillating unit 23, the pulse current having a current value (peak current value) corresponding to the output current of the light receiving element 1 is Thus, the drive current of the laser light source 200 is controlled.

As described above, according to the laser light source control device 100A according to the second embodiment of the present invention, in the normal case (when the abnormality of the pulse voltage Va is not detected by the abnormality detection unit 24), the control unit 2A The drive current of the laser light source 200 is controlled so that the pulse current has a current value corresponding to the output current of the light receiving element 1. For this reason, it is possible to reduce the power consumption of the laser light source 100 compared with the case where the drive current is a constant current (for example, when the drive current remains the peak current).
On the other hand, when the abnormality of the pulse voltage Va is detected by the abnormality detection unit 24, the control unit 2A stops the drive current of the laser light source 200, so that the power consumption of the laser light source 200 can be stably reduced.

In this embodiment, as shown in FIG. 4A, an example in which an abnormality occurs in which the pulse voltage Va output from the pulse oscillating unit 23 remains High (the peak voltage value Vdd remains) is taken as an example. However, the present invention is not limited to this, and when an abnormality occurs in which the pulse voltage Va output from the pulse oscillating unit 23 remains low (i.e., remains GND), the control unit 2A performs laser processing. It is also possible to configure the driving current of the light source 200 to be stopped. In this case, the reference voltage Vref may be set to a value smaller than the voltage Vb output when the pulse voltage Va is normal and larger than GND. Then, when the output voltage Vb <the reference voltage Vref, the voltage Vc output from the comparator 242 may be set to be High (voltage value Vdd).
In addition, any of an abnormality in which the pulse voltage Va output from the pulse oscillating unit 23 remains High (the peak voltage value Vdd remains) and an abnormality that remains Low (the same as GND) occurs. The control unit 2A can be configured to stop the drive current of the laser light source 200. In this case, two reference voltages Vref1 and Vref2 (Vref1> Vref2) are set, and when the output voltage Vb> the reference voltage Vref1 or the output voltage Vb <the reference voltage Vref2, the output is made from the comparator 242. The voltage Vc to be set may be set to High (voltage value Vdd). In this case, a so-called window comparator is preferably used as the comparator 242.

<Third Embodiment>
FIG. 5 is a block diagram showing a schematic configuration of a laser pointer to which the laser light source control device according to the third embodiment of the present invention is applied.
As shown in FIG. 5, the laser pointer according to the present embodiment also includes a laser light source 200 and a laser light source control device 100B. However, the configuration of the laser light source control device 100B is different from the laser light source control device 100 according to the first embodiment and the laser light source control device 100A according to the second embodiment.
Hereinafter, in the laser light source control device 100B according to the present embodiment, the same components as those of the laser light source control device 100 according to the first embodiment and the laser light source control device 100A according to the second embodiment are denoted by the same reference numerals. The description thereof will be omitted as appropriate, and different parts from the first and second embodiments will be mainly described.

  The laser light source control device 100B according to the present embodiment is a device for stabilizing the amount of laser light emitted from the laser light source 200, and includes a light receiving element 1, a control unit 2A, and a power supply unit 3A. The light receiving element 1 and the control unit 2A have the same configuration as that of the second embodiment, and only the power supply unit 3A is different from the power supply unit 3 of the second embodiment.

The power supply unit 3A of the present embodiment supplies a drive voltage to each of the laser light source 200, the light receiving element 1, and the control unit 2A (control unit main body 21).
Specifically, the power supply unit 3A of the present embodiment includes only the constant voltage power supply 31 that outputs a constant voltage Vin, and the voltage changing unit 32 like the power supply unit 3 of the first embodiment or the second embodiment. Is not provided.
The power supply unit 3A (constant voltage power supply 31) supplies the output voltage Vin of the constant voltage power supply 31 to any of the laser light source 200, the light receiving element 1, and the control unit 2A.

Accordingly, the laser light source control device 100B according to the present embodiment is different from the laser light source control device 100 according to the first embodiment and the laser light source control device 100A according to the second embodiment in various laser light sources 200 having different driving voltages. It does not have versatility applicable to it.
However, the laser light source control device 100B according to the present embodiment includes the control unit 2A in the same manner as the laser light source control device 100 according to the first embodiment and the laser light source control device 100A according to the second embodiment. The power consumption of 200 can be stably reduced.

DESCRIPTION OF SYMBOLS 1 ... Light receiving element 2, 2A ... Control part 3, 3A ... Power supply part 21 ... Control part main body 22 ... Transistor 31 ... Constant voltage power supply 32 ... Voltage change part 33, 34 ... Switch 100 ... Laser light source controller 200 ... Laser light source

Claims (4)

A laser light source control device for stabilizing the amount of laser light emitted from a laser light source,
A light receiving element that detects a light amount of the laser light emitted from the laser light source and outputs a current corresponding to the detected light amount;
A control unit for controlling the drive current of the laser light source in accordance with the output current of the light receiving element so that the output current of the light receiving element is constant;
A power supply unit that supplies a first drive voltage to the laser light source and supplies a second drive voltage to each of the light receiving element and the control unit;
The power supply unit is
A constant voltage power supply that outputs a constant voltage;
A voltage changing unit for changing and outputting the output voltage of the constant voltage power source,
The power supply unit supplies, as the first drive voltage, one of an output voltage of the constant voltage power supply and an output voltage of the voltage changing unit that can be selected and supplied to the laser light source, and the second drive. As the voltage, the output voltage of the constant voltage power supply is supplied to each of the light receiving element and the control unit, or one of the output voltage of the constant voltage power supply and the output voltage of the voltage changing unit Is selectively supplied to each of the light receiving element and the control unit. The controller is
A pulse oscillation unit that outputs a pulse voltage;
An abnormality detection unit for detecting an abnormality of the pulse voltage output from the pulse oscillation unit;
If no abnormality of the pulse voltage is detected by the abnormality detection unit, a pulse having a current value corresponding to the output current of the light receiving element based on the output current of the light receiving element and the pulse voltage output from the pulse oscillating unit Control the drive current of the laser light source so as to become current,
2. The laser light source control device according to claim 1, wherein when an abnormality of a pulse voltage is detected by the abnormality detection unit, the drive current of the laser light source is stopped. A laser light source control device for stabilizing the amount of laser light emitted from a laser light source,
A light receiving element that detects a light amount of the laser light emitted from the laser light source and outputs a current corresponding to the detected light amount;
A control unit for controlling the drive current of the laser light source in accordance with the output current of the light receiving element so that the output current of the light receiving element is constant;
A power supply unit that supplies a drive voltage to each of the laser light source, the light receiving element, and the control unit;
The controller is
A pulse oscillation unit that outputs a pulse voltage;
An abnormality detection unit for detecting an abnormality of the pulse voltage output from the pulse oscillation unit;
If no abnormality of the pulse voltage is detected by the abnormality detection unit, a pulse having a current value corresponding to the output current of the light receiving element based on the output current of the light receiving element and the pulse voltage output from the pulse oscillating unit Control the drive current of the laser light source so as to become current,
The laser light source control device characterized in that when the abnormality of the pulse voltage is detected by the abnormality detector, the drive current of the laser light source is stopped. A laser light source;
A laser pointer comprising: the laser light source control device according to claim 1.

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