JPH0736464U - Laser equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents condensation on the output mirror of the laser tube and suppresses deformation due to overheating. [Structure] The water pipe 40 is attached to the peripheral wall of the laser tube 1 in contact therewith. A temperature sensor 2 is attached to the peripheral wall of the laser tube 1, and a dew condensation sensor 3 is attached near the output mirror 10. When the dew condensation sensor 3 detects a predetermined reference humidity or higher, the microcomputer 5 closes the solenoid valve 4 attached to the cooling water pipe 40. When the temperature sensor 2 detects a temperature above the first reference value below the reference humidity, the solenoid valve 4 opens, and when a temperature above the second reference value is detected, a power source connected to the laser tube 1 regardless of the humidity. Circuit 8
Is forcibly turned off.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to various laser devices such as a laser marking device and a laser length measuring device.

[0002]

[Prior art]

 The laser marking device is, for example, a device for drawing characters or figures by deflecting laser light from a carbon dioxide gas laser in a two-dimensional direction by a scanner and irradiating the laser light on the surface of a mating member. Fig. 5 shows the structure of a conventional laser marking device. A pair of electrodes (14) and (14) are arranged inside the laser tube (1), and a power circuit (8) is connected to both electrodes. Has been. The inside of the laser tube (1) is filled with carbon dioxide gas, and an output mirror (10) and a reflection mirror (11) are arranged to face each other in the longitudinal direction of the tube. When the power circuit (8) is operated and a predetermined voltage is applied to the electrodes (14) and (14), a laser beam is emitted from the output mirror (10), and the laser beam is reflected by the reflecting mirror (13). After passing through the lenses (15), (15) and (15), the light is input to the X-axis scanner (16a) and the Y-axis scanner (16b). As a result, the laser beam is scanned in a two-dimensional direction, and a graphic element is drawn on the surface of the object (9). By the way, the laser tube (1) generates heat due to the laser oscillation operation, and there is a possibility that the peripheral wall and the output mirror (10) may be deformed due to overheating. Therefore, as shown in FIG. 6, fins (12) for heat dissipation are formed on the peripheral wall, and the laser tube (1) is air-cooled by a cooling fan (90) arranged outside the laser tube. Further, it has been proposed to arrange a cooling water pipe (40) on the peripheral wall of the laser tube (1) and cool it by water cooling.

[0003]

[Problems to be solved by the device]

 However, in the conventional laser marking device, when the temperature of the cooling water flowing through the cooling water pipe (40) becomes low, for example, in winter, when the humidity of the outside air is high, dew condensation occurs on the output mirror (10). If dirt is attached to the output mirror (10) along with this, not only the output level of the laser beam is lowered, but also the dirty area is irradiated with the laser beam, which causes local heat generation, and the output mirror (10 10) may be deformed or damaged. An object of the present invention is to provide a laser device capable of preventing overheating of a laser tube and preventing dew condensation on an output mirror.

[0004]

[Means for solving the problem]

 A laser marking device is provided with a cooling water pipe (40) for cooling a peripheral wall of a laser tube (1) which is connected to a power supply circuit (8) and emits laser light from an output mirror (10). The valve mechanism for opening and closing the flow path of the cooling water pipe (40), the temperature sensor (2) attached to the peripheral wall of the laser tube (1) to detect the temperature, and the laser tube (1). The operation of the power supply circuit (8) and the valve mechanism is performed based on the detection of the dew sensor (3) attached to the vicinity of the output mirror (10) for detecting humidity and the temperature sensor (2) and the dew sensor (3). And control means for controlling. The control means detects that the humidity in the vicinity of the output mirror (10) is lower than a predetermined humidity reference value and the temperature of the peripheral wall of the laser tube (1) is higher than a predetermined first temperature reference value, When the valve mechanism is opened and it is detected that the temperature of the peripheral wall of the laser tube (1) exceeds a predetermined second temperature reference value which is higher than the first temperature reference value, the dew condensation sensor (3) detects it. Regardless, the power supply operation of the power supply circuit (8) is stopped.

[0005]

[Action]

 The humidity reference value is set to a limit value (for example, 97%) that may cause dew condensation on the output mirror (10) when the humidity is exceeded. The second temperature reference value is set to a limit temperature (for example, 45 ° C.) at which a problem such as deformation of the laser tube (1) due to overheating occurs when this temperature is exceeded. On the other hand, the first temperature reference value is lower than the limit temperature, and laser oscillation can be continued even if this temperature is exceeded, but further temperature rise is set to an undesirable temperature (for example, 30 ° C.). When the humidity in the vicinity of the output mirror (10) is higher than the humidity reference value, there is a risk of dew condensation due to a further temperature decrease or humidity increase, so the valve mechanism is closed and the supply of cooling water is cut off. To be done. When the temperature of the peripheral wall of the laser tube (1) is lower than the first temperature reference value, cooling by water cooling is not necessary, so the valve mechanism is closed and the supply of cooling water is cut off. When the temperature of the peripheral wall of the laser tube (1) rises above the predetermined first temperature reference value, it is desirable to perform cooling by water cooling, but if the humidity at that time exceeds the reference value, condensation may occur. Therefore, open the valve mechanism and perform water cooling only when the reference humidity is not exceeded. Also, when the temperature of the peripheral wall of the laser tube (1) exceeds the second temperature reference value, the laser tube (1) is overheated, so the power supply operation of the power supply circuit (8) is immediately stopped and cooling is performed. The laser oscillation operation is forcibly stopped regardless of whether or not cooling water is flowing through the water pipe (40).

[0006]

[Effect of device]

 According to the laser device of the present invention, the combination of the temperature sensor and the condensation sensor is used to accurately detect the signs that the laser tube is overheated or the output mirror is condensed, and the laser tube is not deformed or the output mirror is damaged. It can be prevented in advance.

[0007]

【Example】

An example in which the present invention is applied to a laser marking device will be described in detail with reference to the drawings. The scanning system such as a scanner and a lens that constitute the laser marking device has the same configuration as that of the conventional one, and therefore, illustration and description thereof will be omitted. As in the conventional case of FIG. 6, a plurality of air-cooling fans (90) are provided outside the laser tube (1) in which carbon dioxide gas is sealed, facing the side surface of the laser tube (1). The air volume of one fan (90) is 1.3 m ³ / min. These fans 90 are continuously turned on when the laser tube 1 is used. Further, cooling water pipes (40) are arranged in contact with both side surfaces and an upper surface of the laser tube (1). The laser output of the laser tube (1) is 10W. As shown in FIG. 1, the cooling water pipe (40) is connected to the tap water faucet (41) via a solenoid valve (4). When the laser tube (1) is on standby, the faucet (41) is open and the solenoid valve (4) is closed. When the solenoid valve (4) is opened, the cooling water supplied from the faucet (41) flows through the cooling water pipe (40) and circulates, and then is discharged from the drain pipe (42) to the outside. The flow rate of the cooling water flowing through the cooling water pipe (40) is about 3 liters / min.

A temperature sensor (2) is attached to the upper surface of the laser tube (1) with an epoxy adhesive. The temperature sensor (2) is composed of, for example, a platinum thermocouple or a thermistor, and in the case of the thermistor, the electric resistance value decreases as the temperature rises. A mirror cover (17) is attached to the laser tube (1) so as to surround the output mirror (10), and a dew condensation sensor (3) is attached to the mirror cover (17) with an epoxy adhesive. ing. The dew condensation sensor (3) is composed of, for example, a humidity sensitive resistor, and its electric resistance value increases as the humidity increases. The two lead wires (20) and (21) drawn from the temperature sensor (2) and the two lead wires (30) and (31) drawn from the condensation sensor (3) are respectively the sensor circuit (6). Is connected to. The sensor circuit (6) has three output terminals (60) (61) (62), and these output terminals (60) (61) (62) are respectively connected to the input ports of the microcomputer (5). There is. The output port of the microcomputer (5) is connected to the solenoid valve (4) and the power supply circuit (8) to control the operation of the solenoid valve (4) and the power supply circuit (8).

As shown in FIG. 3, the sensor circuit (6) is divided into two parts, a dew condensation resistance sensing part (74) and a temperature resistance sensing part (7). In the dew condensation resistance sensing unit (74), the two lead wires (30) and (31) of the dew condensation sensor (3) are connected to the reference voltage source Vref and the ground (76), respectively. A resistor Rx is provided between the reference voltage source Vref and one of the lead wires (30), and the connection point between the resistor Rx and the lead wire (30) is connected to the inverting input terminal of the first comparator (75). is doing. Therefore, if the resistance value of the dew condensation sensor (3) changes, the voltage applied to the inverting input terminal of the first comparator (75) also changes accordingly.

A variable resistor Ry is provided between the reference voltage source V1 and the ground (73), and the variable resistor Ry is connected to the non-inverting input terminal of the first comparator (75) via the resistor Ra. The voltage source E1 is connected to the output terminal of the first comparator (75) via the resistor Rc. The connection point between the resistor Ra and the non-inverting input terminal and the output terminal of the first comparator (75) are connected to each other via the resistor Rb. In this way, the non-inverting input terminal of the first comparator (75) is positively fed back to form a known hysteresis comparator. The output terminal of the first comparator (75) is connected to the output terminal (60). When the humidity is low, the voltage applied to the non-inverting input terminal is higher than the voltage applied to the inverting input terminal, and the signal H is output as shown in FIG. 2 (a).

In the temperature resistance sensing unit (7), the two lead wires (20) and (21) of the temperature sensor (2) are connected to the reference voltage source V2 and the ground (76), respectively. A resistor Rz is interposed in the lead wire (21) on the ground (76) side, and the connection point between the resistor Rz and the lead wire (21) is connected to the inverting input terminal of the second comparator (70). Therefore, if the resistance value of the temperature sensor (2) changes, the voltage applied to the inverting input terminal also changes accordingly. The peripheral circuit (72) of the second comparator (70) is configured similarly to the dew condensation resistance sensing unit (74) and forms a hysteresis comparator. In the standby state of the laser tube (1), the voltage applied to the non-inverting input terminal is higher than the voltage applied to the inverting input terminal, and as shown in FIG. 2 (b), the second comparator (70) Outputs a signal H. The output side of the second comparator (70) is connected to the output terminal (61).

The connection point between the resistor Rz and the lead wire (21) is connected to the inverting input terminal of the third comparator (71). The peripheral circuit (77) of the third comparator (71) is also constructed in the same manner as the peripheral circuit (72) and forms a hysteresis comparator. When the temperature is low, the voltage applied to the non-inverting input terminal is higher than the voltage applied to the inverting input terminal, and the third comparator (71) outputs the signal H as shown in FIG. 2 (c). . The resistance value of the variable resistor Rx is adjusted so that the voltage applied to the non-inverting input terminal of the second comparator (70) is lower than the voltage applied to the non-inverting input terminal of the third comparator (71). To be done. Here, since the same input voltage is applied to the inverting input terminals of the second and third comparators (70) (71), when the voltage applied to the inverting input terminals rises, the second comparator (70) 3 It will be inverted faster than the comparator (71). The output terminal of the third comparator (71) is connected to the output terminal (62).

The circuit operation of the sensor circuit (6) and the microcomputer (5) shown in FIG. 3 will be described below with reference to FIGS. 2 and 4. When the humidity rises, the electric resistance value of the dew condensation sensor (3) increases as described above. In response to this, the voltage applied to the inverting input terminal of the first comparator (75) also increases. At the resistance value when the absolute humidity exceeds the predetermined humidity reference value (97%), the voltage applied to the inverting input terminal is larger than the voltage applied to the non-inverting input terminal. As a result, the first comparator (75) is inverted and outputs the signal L as shown in FIG. 2 (a). The inverted signal L is input from the output terminal (60) to the microcomputer (5). When the humidity falls below the reference value, the first comparator (75) is inverted again and outputs the signal H.

On the other hand, when the temperature of the peripheral wall of the laser tube (1) increases, the resistance value of the temperature sensor (2) decreases and the voltage applied to the inverting input terminal of the second comparator (70) increases. When the temperature is equal to or higher than the first reference value, that is, 30 ° C. or higher in the embodiment, the voltage applied to the inverting input terminal becomes higher than the voltage applied to the non-inverting input terminal. As a result, the second comparator (70) is inverted and outputs the signal L as shown in FIG. 2 (b). The inverted signal L is input from the output terminal (61) to the microcomputer (5).

When the temperature further rises, the voltage input to the inverting input terminals of the second and third comparators (70) and (71) continues to rise, and the second comparator (70) maintains the inverted state. After that, when the temperature reaches the second reference value, which is 45 ° C. or higher in the embodiment, the voltage applied to the inverting input side of the third comparator (71) is higher than the voltage applied to the non-inverting input terminal. Also grows. As a result, the third comparator (71) is inverted and outputs the signal L as shown in FIG. 2 (c). The inverted signal L is input from the output terminal (62) to the microcomputer (5).

As shown in FIG. 4, the microcomputer (5) first receives a signal from the sensor circuit (6) in step S1, and determines in step S2 whether or not the humidity is equal to or higher than a reference value. If YES, the solenoid valve (4) is closed in step S3. Therefore, no cooling water flows through the cooling water pipe (40).

When the humidity is lower than the reference value and NO is determined in step S2, it is determined in step S4 whether or not the temperature is equal to or higher than the first reference value. If NO, the solenoid valve (4) is closed in step S5 and the process returns to step S1. Therefore, in this case as well, the cooling water does not flow through the cooling water pipe (40). If the temperature is equal to or higher than the first reference value and YES is determined in step S4, the solenoid valve (4) is opened in step S6. As a result, the cooling water flows through the cooling water pipe (40) shown in FIG. 1, and the laser tube (1) is cooled. Then, in step S7, it is determined whether or not the temperature is equal to or higher than the second reference value. If NO, the process returns to step S1. If the temperature is equal to or higher than the second reference value and YES is determined, the power supply circuit (8) is turned off in step S8. As a result, the solenoid valve (4) remains open, the cooling water continues to flow through the cooling water pipe (40), the emission of the laser beam is stopped, and the laser tube (1) is prevented from overheating. Even if the humidity is above the reference value and the solenoid valve (4) is closed in step S3 and cooling water is not flowing through the cooling water pipe (40), the temperature is above the second reference value in step S7. In other words, when the microcomputer (5) senses the reverse signal L of the third comparator (71), the power supply circuit (8) is forcibly turned off in step S8.

When the power supply circuit (8) is turned off and the temperature of the peripheral wall of the laser tube (1) falls below the second reference value, the third comparator (71) is inverted again and outputs the signal H. In response to this, the microcomputer (5) can turn on the power supply circuit (8) to emit a laser beam from the laser tube (1). At this time, if the humidity is below a predetermined value, the solenoid valve (4) is opened and the cooling water is flown through the cooling water pipe (40). Further, when the temperature of the peripheral wall of the laser tube (1) becomes lower than the first reference value, the second comparator (70) is inverted again and outputs the signal H. When the microcomputer (5) detects the signal H, it closes the solenoid valve (4) to stop the flow of cooling water. As a result, only the air cooling by the fan (90) is performed, and the laser tube (1) is prevented from being overcooled.

As described above, if the outside air is at or above the reference humidity, the cooling water does not flow due to the detection signal from the dew condensation sensor (3), so dew condensation can be prevented in advance. If the temperature of the peripheral wall of the laser tube (1) is below the first reference value below the reference humidity, water cooling is started, and if it is above the second reference value, whether cooling water is flowing or not. Regardless of this, since the laser beam emission is stopped, it is possible to prevent the temperature of the laser tube (1) from rising abnormally. Further, the laser marking device employs a water cooling system in which the cooling water that flows through the cooling water pipe (40) and rises in temperature is discharged to the outside, so the device configuration becomes compact.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the scope of the utility model registration request or reducing the scope. Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the scope of claims for utility model registration. For example, the present invention is not limited to the laser marking device, and can be of course implemented in various laser devices such as a laser length measuring machine and a laser processing machine.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a main part of a laser marking device.

FIG. 2 is a graph illustrating the operation of each comparator.

FIG. 3 is a circuit diagram of a sensor circuit.

FIG. 4 is a flowchart showing the operation of the laser marking device.

FIG. 5 is a diagram showing a configuration of a conventional laser marking device.

FIG. 6 is a perspective view of a laser tube of a conventional laser marking device.

[Explanation of symbols]

 (1) Laser tube (2) Temperature sensor (3) Condensation sensor (4) Solenoid valve

Claims (1)

[Scope of utility model registration request] 1. An output mirror (1) connected to a power supply circuit (8)
In a laser device constituted by arranging a cooling water pipe (40) for cooling the peripheral wall of a laser tube (1) which emits laser light from (0), the flow of the cooling water pipe (40) A valve mechanism that opens and closes the passage, a temperature sensor (2) that is attached to the peripheral wall of the laser tube (1) to detect temperature, and a temperature sensor that is attached near the output mirror (10) of the laser tube (1) to detect humidity. A condensation sensor (3) for controlling the operation of the power supply circuit (8) and the valve mechanism based on the detections of the temperature sensor (2) and the condensation sensor (3), and the control means is an output mirror. (10) Humidity in the vicinity is lower than the specified humidity reference value,
And when it is detected that the temperature of the peripheral wall of the laser tube (1) is higher than the predetermined first temperature reference value, the valve mechanism is opened,
When it is detected that the temperature of the peripheral wall of the laser tube (1) exceeds a predetermined second temperature reference value that is higher than the first temperature reference value, the power circuit regardless of the detection of the dew condensation sensor (3). A laser device characterized in that the power supply operation of (8) is stopped.