JP2005051174A - Laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser device which reduces the start time of the device, suppresses the rated power consumption of the whole device, and can efficiently attain temperature stabilization when driving the laser diode. <P>SOLUTION: The laser device irradiates a stimulated light from the laser diode to a solid laser medium and emits laser beams. The laser device has a cooling means for cooling a cooling medium for cooling the laser diode, a heating means for warming the cooling medium cooled by the cooling means, a temperature sensor for detecting the cooling temperature of the cooling medium, and a control means for controlling to drive the cooling means and the heating means based on the temperature information detected by the temperature sensor, and also for switching a drivable state of the laser diode based on the detected temperature information, to switch power in driving the heating means by referencing the switched temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser device that emits laser light by irradiating a solid laser medium with excitation light from a laser diode.

  In a laser apparatus that irradiates a solid-state laser medium with excitation light emitted by a laser diode and emits laser light from the solid-state laser medium, the temperature of the laser diode needs to be constant in order to make the wavelength of the excitation light constant. is there. In order to keep the temperature of the laser diode constant, a method is adopted in which the cooling water cooled by the cooler is circulated to absorb the heat generated from the laser diode.

In addition to the above-mentioned cooler, a heater is provided in the cooling water circulation path to keep the temperature of the cooling water fine by adjusting the temperature of the cooling water by warming the temperature of the cooling water or by using the cooler and the heater together. There is also a device that circulates the light in the laser diode (see, for example, Patent Document 1).
JP 2002-76500 A

  However, since the drive power of the heater is large, considering that the laser diode can be driven while simultaneously operating the heater in addition to the cooler, the power consumption of the entire device exceeds the rated power consumption. Increased (1500 VA or more). For this reason, the conventional apparatus has a problem that a single power source must be used for the heater, not the wall outlet.

  Also, if the cooling water is cold at the start of the device, the temperature of the cooling water must be warmed to a predetermined temperature by the heater. However, if the power capacity of the heater is low, the temperature of the cooling water cannot be raised quickly. There was a problem that it took time to start.

  In view of the above problems, the present invention provides a laser device capable of efficiently achieving temperature stabilization when driving a laser diode while shortening the startup time of the device and suppressing the rated power consumption of the entire device. This is a technical issue.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

  (1) In a laser device that emits laser light by irradiating a solid laser medium with excitation light from a laser diode, cooling means for cooling a cooling medium for cooling the laser diode, and cooling cooled by the cooling means A heating unit that warms the medium, a temperature sensor that detects a cooling temperature of the cooling medium, and a temperature that is detected while controlling the driving of the cooling unit and the heating unit based on temperature information detected by the temperature sensor Control means for switching the driveable state of the laser diode based on the information and switching the power when driving the heating means in relation to the switching temperature.

  (2) The control means of (1) controls the driving of the cooling means and the heating means, and the laser diode when the detected temperature information is within a predetermined temperature range including the predetermined set temperature T1. Is switched to a drivable state, and the temperature information detected by the temperature sensor is set to a predetermined set temperature (T1). The temperature information is set to a predetermined temperature (T2) that is set below the predetermined temperature range. The power for driving the heating means is switched depending on whether or not it has reached.

  (3) In the control means of (2), the temperature information detected by the temperature sensor detected when the temperature information detected by the temperature sensor is lower than the predetermined temperature (T2). When the temperature is equal to or higher than the temperature (T2), the power for driving the heating unit is switched to a small power obtained by subtracting the power necessary for driving the laser diode.

  ADVANTAGE OF THE INVENTION According to this invention, temperature stabilization when driving a laser diode can be achieved efficiently, shortening the starting time of an apparatus and suppressing the rated power consumption of the whole apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external view of an ophthalmic laser photocoagulation apparatus using a slit lamp. FIG. 2 is a schematic diagram of an optical system of the apparatus, and FIG. 3 is a schematic diagram of a configuration of a cooling unit and a cooling control system.

  Reference numeral 1 denotes a laser device main body, which stores a laser oscillator 10, which will be described later, a part of a light guide optical system for guiding and irradiating laser light to an affected part of a patient's eye, a control unit 80, and the like. A control unit 2 of the apparatus is provided with various switches for setting and inputting laser irradiation conditions. Reference numeral 3 denotes a foot switch for transmitting a trigger signal for laser irradiation.

  Reference numeral 4 denotes a slit lamp, which includes an observation optical system for observing a patient's eye and a part of a light guide optical system. Reference numeral 5 denotes a fiber for guiding laser light from the main body 1 to the slit lamp 4. Reference numeral 6 denotes a frame for moving the slit lamp 4 up and down.

  Reference numeral 10 denotes a laser oscillator, which internally includes an Nd: YAG crystal 11 that is a solid laser medium, a laser diode (hereinafter simply referred to as LD) 12 that is an excitation light source, and a nonlinear crystal that is a wavelength converter (hereinafter referred to as a wavelength converter). , Simply NLC) 13, total reflection mirror (hereinafter simply referred to as HR) 14, output mirror 15, and condenser lens 16. In this embodiment, a KTP crystal is used as the nonlinear crystal.

  The Nd: YAG crystal 11 emits light having a plurality of oscillation lines in the near infrared region by excitation light from the LD 12. Therefore, the apparatus of this embodiment uses about 1064 (1064.1) nm, which has a high output among the plurality of oscillation lines, and emits a laser beam of about 532 nm (green). The HR 14 has total reflection for 1064 nm and 532 nm, and the output mirror 15 has characteristics of reflecting 1064 nm and transmitting 532 nm.

  As shown in FIG. 3, the oscillation unit 20 is cooled by circulating the cooling water of the cooling unit 30. The configuration of the cooling unit 30 will be described below. A cooling unit 40, a heater 50, and a stirring blade 60 are disposed inside the constant temperature bath 31 that stores cooling water having a constant temperature. The cooling unit 40 is connected to the outside of the thermostatic bath 31 by a compressor 41, a condenser 42, and a condenser 43 by piping, and a cooling cycle is formed. The heater 50 is driven by a heater driving unit 51 outside the thermostat 31. The stirring blade 60 is driven by a stirrer driving unit 61 outside the constant temperature bath 31, and the cooling water cooled by the cooling unit 40 inside the constant temperature bath 31 and the cooling water heated by the heater 50 are stirred by the stirring blade 60. The Reference numeral 70 denotes a temperature sensor that detects the temperature of the cooling water inside the thermostatic chamber 31. Cooling water inside the thermostat 31 is circulated by the pump 32, foreign matters such as dust are removed by the filter 33, circulates through the oscillation unit 20, and returns to the thermostat 31. Of course, the thermostat 31, the pump 32, the filter 33, and the oscillation unit 20 are connected by piping. The cooling water absorbs heat generated by the LD 12 inside the oscillation unit 20 so that the LD 12 has a constant temperature and outputs at a constant wavelength. Further, heat generated by the Nd: YAG crystal 11 is also absorbed by circulating around the Nd: YAG crystal 11. A glass tube 17 transmits excitation light from the LD 12 and serves to circulate cooling water around the Nd: YAG crystal 11.

  A control unit 80 controls each unit of the apparatus based on signals from the control unit 2 and the foot switch 3. Further, the control unit 80 controls the rotation speed of the compressor 41 and the heater drive so that the temperature of the cooling water in the thermostatic bath 31 becomes a predetermined set temperature T1 (for example, 25 ° C.) based on the temperature information from the temperature sensor 70. The drive of the unit 51 is controlled. Further, the LD 12 can be driven when the temperature of the cooling water is within a certain temperature range (for example, 25 ° C. ± 2 ° C.) with respect to the set temperature T1. Further, depending on whether or not the temperature of the cooling water has reached a predetermined temperature T2 (for example, 22 ° C. which is 3 ° C. lower than 25 ° C.) lower than the temperature range (for example, 25 ° C. ± 2 ° C.) centering on the temperature T1. The electric power when driving the heater 50 is switched.

  Next, a method for emitting laser light based on the above configuration will be described. The surgeon sets laser irradiation conditions by the control unit 2. The control unit 80 drives the pump 32 and the stirrer driving unit 61 to circulate the cooling water. It is assumed that driving the pump 32 requires 100 W of power. It is also assumed that 100 W of electric power is required for the electrical system of the system such as the control unit 2. In addition, it is assumed that the rotation of the compressor 41 requires 200 W of electric power. Since the compressor 41 begins to rotate and the cooling effect begins to appear after about 3 minutes, the compressor 41 is always rotated from the beginning when the apparatus is activated. The compressor 41 is driven at a maximum of 200 W until 3 minutes when the cooling effect starts to appear, but thereafter, it can be continuously changed at 30 to 100% (60 to 200 W). Therefore, the maximum power consumption required for 3 minutes when the apparatus is started is 400 W.

  Here, if the rated power consumption of the entire apparatus is 1000 W, the remaining usable power is 600 W. The control unit 80 switches and controls the remaining 600 W as follows. It is confirmed whether or not the temperature detected from the temperature sensor 70, that is, the temperature of the cooling water is lower than a predetermined temperature T2 (22 ° C.), and when the temperature of the cooling water is lower than the predetermined temperature T2 as shown in FIG. Since the LD 12 is not in a drivable state, the heater 50 is driven with 600 W of usable power. Thereby, the temperature of cooling water can be raised efficiently. The heater drive unit 51 controls the amount of heat for heating the cooling water by controlling the energization time for energizing the heater 50.

  When the temperature of the cooling water becomes equal to or higher than the predetermined temperature T2, the heater driving unit 51 switches the power for driving the heater 50 to the power obtained by subtracting the power required for driving the LD 12. That is, assuming that the power required for driving the LD 12 is 400 W, the power for driving the heater 50 when the temperature is equal to or higher than the predetermined temperature T2 is 200 W. Further, after about 3 minutes from the start of rotation of the compressor 41, the compressor 41 and the heater 50 are used together to stabilize the temperature of the cooling water so that it becomes the set temperature T1 (25 ° C.). Although the cooling capacity is varied by variably controlling the rotation speed of the compressor 41, the heater 50 is also used in order to efficiently achieve temperature stability. That is, when the temperature of the cooling water is equal to or higher than the predetermined temperature T2 and lower than the set temperature T1, the heater 50 is driven at 200 W while slowing the rotation of the compressor 41, and the temperature of the cooling water becomes the set temperature T1. Like that. When the temperature of the cooling water is higher than the set temperature T1, the energization of the heater 50 is turned off while the rotation of the compressor 41 is accelerated so that the temperature of the cooling water becomes the set temperature T1. Further, when the temperature of the cooling water is within a predetermined temperature range (set temperature T1 (25 ° C.) ± 2 ° C.), the control unit 80 sets the LD 12 in a drivable state.

  Thus, by switching the driving power of the heater 50 while using the compressor 41 and the heater 50 together, the power consumption of the entire apparatus can be suppressed to the rated power consumption (1000 W) or less even when the LD 12 is driven. The temperature stability of can be ensured efficiently. Even if the cooling water is cold at the time of starting the apparatus, the heater 50 is driven with a large capacity of 600 W that can be used, so that the temperature of the cooling water can be quickly raised and the startup time can be shortened.

  Note that the condition for switching the driving power of the heater 50 from 600 W to 200 W may be a condition for switching the LD 12 to a drivable state (whether the temperature of the cooling water is at a set temperature of 25 ° C. ± 2 ° C.).

  In addition, after the compressor 41 is driven at 200 W for about 3 minutes from the start of the apparatus, when the cooling effect of the compressor 41 starts to appear, the rotation of the compressor 41 is reduced to 30% (driving power is 60 W) to thereby reduce the cooling water. When the temperature does not reach the predetermined temperature T2, the heater 50 may be driven with the remaining usable electric power of 740W. When the temperature of the cooling water is equal to or higher than the predetermined temperature T2 or the LD 12 can be driven, the electric power for driving the heater 50 is set to 200W.

  In the laser oscillator 10, a resonator 25 is configured by the HR 14 and the output mirror 15, and the NLC 13 is disposed between the rod 11 and the output mirror 15. When the LD 12 is driven by the input of the trigger signal from the foot switch 3 and the excitation laser light from the LD 12 is irradiated onto the rod 11, 1064 nm light is oscillated in the resonator 25, and 1064 nm light is further generated inside the resonator 25. The wavelength is converted to light of 532 nm which is the second harmonic. The obtained laser beam of 532 nm passes through the output mirror 15 and is guided to the fiber 5 through the condenser lens 16. And it irradiates toward the patient's eyes from the irradiation port of the slit lamp 4.

  In this embodiment, the Nd: YAG crystal is used as the solid laser medium, but the present invention is not limited to this, and a known solid laser medium (crystal) can be used. The present embodiment is not limited to an ophthalmic laser treatment apparatus, and can be applied to laser apparatuses for various uses such as medical (including plastic surgery) and industrial (measurement, etc.).

It is an external view of this embodiment. It is the schematic of the optical system of this embodiment. It is the control schematic of the laser cooling system of the apparatus of this embodiment. It is a figure which shows the temperature change of the cooling water of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser apparatus main body 11 Nd: YAG crystal 12 Semiconductor laser 30 Cooling part 31 Constant temperature bath 32 Pump 40 Cooling part 41 Compressor 42 Condenser 43 Condenser 50 Heater 51 Heater drive part 70 Temperature sensor 80 Control part

Claims (3)

In a laser apparatus that emits laser light by irradiating a solid laser medium with excitation light from a laser diode, cooling means for cooling a cooling medium for cooling the laser diode, and a cooling medium cooled by the cooling means are warmed A heating unit, a temperature sensor for detecting a cooling temperature of the cooling medium, and driving of the cooling unit and the heating unit are controlled based on temperature information detected by the temperature sensor, and based on the detected temperature information. And a control means for switching power when the heating means is driven in relation to the switching temperature of the laser diode. The control unit according to claim 1 controls driving of the cooling unit and the heating unit, and can drive the laser diode when the detected temperature information is within a predetermined temperature range including the predetermined set temperature T1. Whether the temperature information detected by the temperature sensor is set to a predetermined set temperature (T1) has reached a predetermined temperature (T2) determined to be equal to or lower than the predetermined temperature range. A laser apparatus characterized in that the power for driving the heating means is switched depending on whether or not. The control means according to claim 2 is configured such that when the temperature information detected by the temperature sensor is lower than the predetermined temperature (T2), the detected temperature information is the predetermined temperature (T2) with respect to electric power for driving the heating means. In this case, the laser device is characterized in that the electric power for driving the heating means is switched to a small electric power obtained by subtracting the electric power necessary for driving the laser diode.

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