Patent Publication Number: US-2023155350-A1

Title: Control device and method for laser device and laser measurement device

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application is continuation of International Application No. PCT/CN2021/104703, filed on Jul. 6, 2021, which claims the priority of Chinese Patent Application No. 202011545557.5, filed on Dec. 24, 2020, the entire contents of both of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of laser measurement and, more particularly, to a control device for a laser device, a control method for the laser device, and a laser measurement device including the above control device. 
     TECHNICAL BACKGROUND 
     Various laser measurement tools are widely used in industries such as construction. However, the laser device used by the laser measurement tool to generate laser inevitably generates heat during operation, which leads to continuous increase of the temperature of the laser device and the surrounding devices. On one hand, the aging degree of the laser device and other surrounding devices thereof may be accelerated and the service life thereof may be reduced. On the other hand, the measurement accuracy of such laser measurement tools may also be recured due to factors such as temperature drift. 
     SUMMARY 
     In view of the deep understanding of the problems discussed in the background technology, the present disclosure provides a control device and a corresponding control method for controlling the temperature of the laser device by using a logic circuit to change the driving power of the driving signal. 
     The first aspect of the present disclosure provides a control device for controlling the temperature of a laser device, where the control device includes: a pulse width modulation (PWM) signal generator, where the PWM signal generator is configured to generate a PWM signal; a temperature acquisition circuit, where the temperature acquisition circuit is configured to acquire a temperature of the laser device and convert the temperature into a measurement voltage; a voltage comparator, where the voltage comparator is configured to compare the measurement voltage associated with the temperature of the laser device with a temperature threshold voltage and output a comparison result signal; and a logic circuit, where the logic circuit is configured to generate a drive signal based on the PWM signal and the comparison result signal to drive the laser device. 
     The control device according to the present disclosure can realize, by using simple components such as a voltage comparator and a logic circuit, temperature comparison and generate a driving signal for driving the laser device according to the PWM signal and the comparison result signal when the temperature exceeds a predetermined threshold. As such, the power of the signal driving the laser device can be reduced. In turn, the temperature of the laser device can be controlled, leading to a longer lifetime and improved accuracy of the laser device at a lower cost and higher reliability. 
     In an embodiment according to the present disclosure, a duty ratio of the PWM signal is not less than 5:5. For example, the duty ratio of the PWM signal is not less than 7:3. In one embodiment according to the present disclosure, the logic circuit includes an Exclusive-OR (XOR) gate circuit. For example, in an embodiment according to the present disclosure, the XOR gate circuit is configured to invert, when the acquired measurement voltage associated with the temperature of the laser device is higher than the temperature threshold voltage, the PWM signal to reduce the power to drive the laser device. 
     In an embodiment according to the present disclosure, the temperature acquisition circuit includes a temperature sensor. The temperature sensor is configured to acquire and convert the temperature of the laser device into a measurement voltage. 
     In an embodiment according to the present disclosure, the laser device includes at least one laser diode. 
     A second aspect of the present disclosure provides a laser measurement device, where the laser measurement device includes: a laser device, where the laser device is configured to emit laser for measurement; and a control device for controlling the temperature of the laser device according to the first aspect of the present disclosure. 
     In one embodiment according to the present disclosure, the laser device includes at least one laser diode. 
     In an embodiment according to the present disclosure, the laser measurement device includes a laser leveling device, a laser line projection device and/or a laser distance meter. 
     A third aspect of the present disclosure provides a control method for controlling the temperature of a laser device, where the control method includes: generating a PWM signal; acquiring and converting a temperature of the laser device into a measurement voltage; comparing, by a voltage comparator, the acquired measurement voltage associated with the temperature of the laser device with a temperature threshold voltage, and outputting a comparison result signal; and generating, by a logic circuit, a drive signal based on the PWM signal and the comparison result signal to drive the laser device. 
     The control device according to the present disclosure can realize, by using simple components such as a voltage comparator and a logic circuit, temperature comparison and generate a driving signal for driving the laser device according to the PWM signal and the comparison result signal when the temperature exceeds a predetermined threshold. As such, the power of the signal driving the laser device can be reduced. In turn, the temperature of the laser device can be controlled, leading to a longer lifetime and improved accuracy of the laser device at a lower cost and higher reliability. 
     Optionally, in an embodiment according to the present disclosure, a duty ratio of the PWM signal is not less than 5:5. For example, the duty ratio of the PWM signal is not less than 7:3. In one embodiment according to the present disclosure, the logic circuit includes an XOR gate circuit. In an embodiment according to the present disclosure, the control method further includes inverting, by the XOR gate circuit when the acquired measurement voltage associated with the temperature of the laser device is higher than the temperature threshold voltage, the PWM signal to reduce the power to drive the laser device. 
     Optionally, in an embodiment according to the present disclosure, the temperature acquisition circuit includes a temperature sensor, where acquiring the temperature of the laser device further includes acquiring the temperature of the laser device by the temperature sensor. 
     The control device according to the present disclosure can realize, by using simple components such as a voltage comparator and a logic circuit, temperature comparison and generate a driving signal for driving the laser device according to the PWM signal and the comparison result signal when the temperature exceeds a predetermined threshold. As such, the power of the signal driving the laser device can be reduced. In turn, the temperature of the laser device can be controlled, leading to a longer lifetime and improved accuracy of the laser device at a lower cost and higher reliability. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Embodiments are shown and explained with reference to the accompanying drawings. The drawings are for describing the basic principles, thus showing only the aspects necessary to understand the basic principles. The drawings are not to scale. In the drawings, the same reference numbers refer to similar features. 
         FIG.  1    shows a schematic structural diagram of a control device  100  for controlling the temperature of the laser device according to an embodiment of the present disclosure; 
         FIG.  2    shows a schematic structural diagram of a control device  200  for controlling the temperature of the laser device according to another embodiment of the present disclosure; 
         FIG.  3    shows a schematic structural diagram of a laser measurement device  300  including the control device shown in  FIG.  1    or  FIG.  2   ; and 
         FIG.  4    shows a schematic flowchart of a control method  400  for controlling the temperature of the laser device according to an embodiment of the present disclosure. 
     
    
    
     Other features, characteristics, advantages and benefits of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference will be made to the accompanying drawings which form a part of this disclosure. The accompanying drawings show, by showing examples, specific embodiments in which the present disclosure can be practiced. The exemplary embodiments are not intended to be exhaustive of all embodiments in accordance with the present disclosure. It is to be understood that other embodiments may be utilized and structural or logical modifications may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not limiting, and the scope of the present disclosure is defined by the appended claims. 
     In order to solve the technical problems such as the low lifetime of the laser device, the present application provides a control device for controlling the temperature of the laser device.  FIG.  1    shows a schematic structural diagram of a control device  100  for controlling the temperature of the laser device according to an embodiment of the present disclosure. As shown in  FIG.  1   , the control device  100  for controlling the temperature of the laser device provided according to the present disclosure includes the following parts: 
     a pulse width modulation (PWM) signal generator  110 , where the PWM signal generator  110  is configured to generate a PWM signal, the PWM signal being to be input into the subsequent logic circuit  150 ; 
     a temperature acquisition circuit  120 , where the temperature acquisition circuit  120  is configured to acquire the temperature of the laser device (not shown in  FIG.  1   ) and convert it into a measurement voltage. Therefore, in actual installation, the temperature acquisition circuit  120  may need to be provided close to the laser device, or directly in close contact with the laser device. Of course, those skilled in the art should understand that when, for example, non-contact temperature acquisition is adopted, e.g., when the infrared temperature acquisition method is used, the temperature acquisition circuit  120  can also be arranged far away from the laser device; 
     a voltage comparator  140 , where the voltage comparator  140  is configured to compare the acquired measurement voltage associated with the temperature of the laser device with a temperature threshold voltage and to output a comparison result signal. Here, the temperature threshold voltage, e.g., the threshold voltage  130  shown in the example of  FIG.  1   , is input, for example, through an input terminal of the voltage comparator  140 ; and 
     a logic circuit  150 , where the logic circuit  150  is configured to generate, based on the PWM signal (generated by the PWM signal generator  110 ) and the comparison result signal (the comparison result signal output by the voltage comparator  140 ), a drive signal to drive the laser device. 
     The control device according to the present disclosure can realize, by using simple components such as a voltage comparator  140  and a logic circuit  150 , temperature comparison and generate a driving signal for driving the laser device according to the PWM signal (generated by the PWM signal generator  110 ) and the comparison result signal (the comparison result signal output by the voltage comparator  140 ) when the temperature exceeds a predetermined threshold. As such, the power of the signal driving the laser device can be reduced. In turn, the temperature of the laser device can be controlled, leading to a longer lifetime and improved accuracy of the laser device at a lower cost and higher reliability. 
     In an embodiment according to the present disclosure, the temperature acquisition circuit  120  can be implemented as a temperature sensor. For example, the present embodiment adopts a thermistor, and the resistance of the thermistor is about 2.3K at 68 degrees. This embodiment employs a non-inverting voltage hysteresis comparator as the voltage comparator. The technical solution disclosed in the present disclosure uses a hysteresis voltage of about 300 mv, a high threshold limit Vh of 1.783 v, and a low threshold limit Vl of 1.476 v. When the temperature rises to 68 degrees, through voltage conversion, the temperature detection circuit generates a voltage greater than 1.783V, and the voltage comparator  140  outputs a high level, which is XORed with the PWM signal generated by the PWM generator  110 , thereby reducing the working power of the laser device. The PWM generator  110  can use a single-chip microcomputer or a PWM generating circuit to generate a PWM square wave signal. The temperature acquisition circuit  120  can use an NTC resistor or a temperature detection chip to acquire the current temperature of the laser device. The voltage comparator  150  may use a single-limit comparator, a hysteresis comparator, and/or a window comparator to output the comparison result. The logic circuit  150  may use various gate circuits such as an Exclusive-OR gate circuit. The voltage comparator  140  compares the set voltage value with the voltage value sampled by the NTC, and performs XOR with the signal of the PWM generator  110 , thereby reducing the operating power of the laser device. 
     In an embodiment according to the present disclosure, a duty ratio of the PWM signal generated by the PWM signal generator  110  is not less than 5:5. For example, the duty ratio of the PWM signal generated by the PWM signal generator  110  is not less than 7:3. In one embodiment according to the present disclosure, the logic circuit  150  includes an XOR gate circuit. In an embodiment according to the present disclosure, the XOR gate circuit is configured to invert, when the acquired measurement voltage associated with the temperature of the laser device is higher than the temperature threshold voltage, the PWM signal (generated by the PWM signal generator  110 ) to reduce the power to drive the laser device. 
     Optionally, in one embodiment according to the present disclosure, the temperature acquisition circuit  120  includes a temperature sensor, where the temperature sensor is configured to acquire and convert the temperature of the laser device into a measurement voltage. Optionally, in an embodiment according to the present disclosure, the laser device includes at least one laser diode. 
       FIG.  2    shows a schematic structural diagram of a control device  200  for controlling the temperature of the laser device according to an embodiment of the present disclosure. As shown in  FIG.  2   , the control device  200  for controlling the temperature of the laser device proposed according to the present disclosure includes the following parts: 
     a PWM signal generator  210 , where the PWM signal generator  210  is configured to generate a PWM signal, and the PWM signal is to be input into the following XOR gate circuit  250 ; 
     a temperature sensor  220 , where the temperature sensor  220  is configured to acquire the temperature of the laser device  260  and convert it into a measurement voltage. Thus, it may be necessary to place the temperature sensor  220  close to, or directly in close contact with the laser device  260  in actual installations. Of course, those skilled in the art should understand that when, for example, non-contact temperature acquisition is adopted, e.g., when the infrared temperature acquisition is adopted, the temperature sensor  220  can also be arranged far away from the laser device  260 ; 
     a voltage comparison circuit  240 , where the voltage comparison circuit  240  is configured to compare the acquired measurement voltage associated with the temperature of the laser device  260  with a temperature threshold voltage and to output a comparison result signal. Here, the temperature threshold voltage, e.g., the temperature threshold voltage output by the threshold temperature voltage circuit  230  as shown in the example in  FIG.  2   , is, for example, input through an input terminal of the voltage comparison circuit  240 ; and 
     an XOR gate circuit  250 , where the XOR gate circuit  250  is configured to generate, based on the PWM signal (generated by the PWM signal generator  210 ) and the comparison result signal (the comparison result signal output by the voltage comparator  240 ), a driving signal to drive the laser device  260 . 
     The control device according to the present disclosure can realize, by using simple components such as a voltage comparison circuit  240  and a XOR logic circuit  250 , temperature comparison and generate a driving signal for driving the laser device  260  according to the PWM signal (generated by the PWM signal generator  210 ) and the comparison result signal (the comparison result signal output by the voltage comparator  240 ) when the temperature exceeds a predetermined threshold. As such, the power of the signal driving the laser device  260  can be reduced. In turn, the temperature of the laser device  260  can be controlled, the working stability of the laser device  260  can be improved, leading to a longer lifetime and improved accuracy of the laser device  260  at a lower cost and higher reliability. 
     In an embodiment according to the present disclosure, the temperature sensor  220  can adopt, e.g., a thermistor, and the resistance of the thermistor is about 2.3K at 68 degrees. A non-inverting voltage hysteresis comparator is applied. The technical solution disclosed in the present disclosure uses a hysteresis voltage of about 300 mv, a threshold Vh of 1.783 v, and a threshold Vl of 1.476 v. When the temperature rises to 68 degrees, the temperature detection circuit generates a voltage greater than 1.783V, and the voltage comparison circuit  240  outputs a high level, which is XORed with the PWM signal generated by the PWM generator  210 , thereby reducing the working power of the laser device. The PWM generator  210  may include a single-chip microcomputer or a PWM generating circuit to generate a PWM square wave signal, and the temperature acquisition circuit  220  can use an NTC resistor or a temperature detection chip to acquire the current temperature of the laser device. The voltage comparison circuit  240  may use a single-limit comparator, a hysteresis comparator, and/or a window comparator to output the comparison result. The XOR logic circuit  250  may use various gate circuits such as an XOR or other logic gate. The voltage comparison circuit  240  compares the set voltage value with the voltage value sampled by the NTC, and performs XOR with the signal of the PWM generator  210 , thereby reducing the operating power of the laser device. 
     In an embodiment according to the present disclosure, the duty ratio of the PWM signal generated by the PWM signal generator  210  is not less than 5:5. For example, the duty ratio of the PWM signal generated by the PWM signal generator  210  is not less than 7:3. In one embodiment in accordance with the present disclosure, the XOR circuit  250  is configured to invert, when the acquired measurement voltage associated with the temperature of the laser device  260  is higher than the temperature threshold voltage, the PWM signal (generated by the PWM signal generator  210 ) to reduce the power for driving the laser device  260 . 
     Optionally, in an embodiment according to the present disclosure, the temperature sensor  220  is configured to acquire the temperature of the laser device  260  and convert it into the measurement voltage. Optionally, in one embodiment according to the present disclosure, the laser device  260  includes at least one laser diode. 
       FIG.  3    shows a schematic structural diagram of a laser measurement device  300  including the control device shown in  FIG.  1    or  FIG.  2   . As shown in  FIG.  3   , the laser measurement device  300  provided by the second aspect of the present disclosure includes a laser device  360 , where the laser device  360  is configured to emit laser for measurement. The laser measurement device  300  provided in the second aspect further includes the control device  100  proposed according to the first aspect of the present disclosure for controlling the temperature of the laser device. In one embodiment in accordance with the present disclosure, the laser device  360  includes at least one laser diode. In an embodiment according to the present disclosure, the laser measurement device  300  may be any one of a laser leveling device, a laser line projection device, a laser spot projection device, and a laser distance meter. That is, the control device  100  for controlling the temperature of a laser device proposed according to the present disclosure can be applied to any measuring device having a laser device, and it can control the temperature of the laser device, thereby improving the service life of the laser device. 
       FIG.  4    shows a schematic flowchart of a control method  400  for controlling the temperature of the laser device according to an embodiment of the present disclosure. As shown in  FIG.  4   , the control method  400  for controlling the temperature of a laser device provided by the third aspect of the present disclosure includes the following method steps: 
     Method step  410 : generating a PWM signal; 
     Method step  420 : acquiring the temperature of the laser device and converting it into a measurement voltage; 
     Method step  430 : comparing, by a voltage comparator, the acquired measurement voltage associated with the temperature of the laser device with a temperature threshold voltage, and outputting a comparison result signal; and 
     Method step  440 : generating, by a logic circuit, a drive signal based on the PWM signal and the comparison result signal to drive the laser device. The control device according to the present disclosure can realize, by using simple components such as a voltage comparator and a logic circuit, temperature comparison and generate a driving signal for driving the laser device according to the PWM signal and the comparison result signal when the temperature exceeds a predetermined threshold. As such, the power of the signal driving the laser device can be reduced. In turn, the temperature of the laser device can be controlled, leading to a longer lifetime and improved accuracy of the laser device at a lower cost and higher reliability. 
     Optionally, in an embodiment according to the present disclosure, a duty ratio of the PWM signal is not less than 5:5. For example, the duty ratio of the PWM signal is not less than 7:3. In one embodiment according to the present disclosure, the logic circuit includes an XOR gate circuit. In an embodiment according to the present disclosure, the control method further includes inverting, by the XOR gate circuit when the acquired measurement voltage associated with the temperature of the laser device is higher than the temperature threshold voltage, the PWM signal to reduce the power to drive the laser device. Optionally, in an embodiment according to the present disclosure, the temperature acquisition circuit includes a temperature sensor, where acquiring the temperature of the laser device further includes acquiring the temperature of the laser device by the temperature sensor. 
     The control device according to the present disclosure can realize, by using simple components such as a voltage comparator and a logic circuit, temperature comparison and generate a driving signal for driving the laser device according to the PWM signal and the comparison result signal when the temperature exceeds a predetermined threshold. As such, the power of the signal driving the laser device can be reduced. In turn, the temperature of the laser device can be controlled, leading to a longer lifetime and improved accuracy of the laser device at a lower cost and higher reliability. 
     Although various exemplary embodiments of the present disclosure have been described, it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and spirit of the present disclosure. One or some of the advantages of the present disclosure are realized within the scope of the present disclosure. Other components performing the same function may be substituted as appropriate to those skilled in the art. It should be understood that features explained herein with reference to a particular figure may be combined with features of other figures, even in those cases where this is not explicitly mentioned. Furthermore, the methods of the present disclosure may be implemented either in all software implementations using appropriate processor instructions or in hybrid implementations that utilize a combination of hardware logic and software logic to achieve the same results. Such modifications to the solution according to the present disclosure are intended to be covered by the appended claims.