JP2602266B2 - Laser marker and laser oscillator using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a laser marker using a liquid crystal element as a pattern mask for imprinting pattern information on a workpiece and a laser oscillator using the same.

[Prior art]

Generally, a work piece, for example, an electronic component has its serial number,
The date of manufacture, the name and other symbols are engraved to indicate the source. Conventionally, in a clear method, a pattern mask is formed by etching a metal plate to form a through-hole corresponding to a code as pattern information. The pattern mask is in contact with the electronic component, and after the paint is applied to the pattern mask, if the pattern mask is removed, the code is attached to the electronic component. According to this method, it is necessary to replace the pattern mask with an appropriate one each time the type of electronic component changes, which has disadvantages that a large replacement time and a large number of pattern masks must be prepared. Therefore, the laser marker disclosed in Japanese Patent Application Laid-Open No. Sho 60-174671 uses a liquid crystal element as a pattern mask, arranges the liquid crystal element between a laser oscillator and a workpiece, and processes the liquid crystal element on a display portion of the liquid crystal element. If the voltage of the sign to be imprinted on the object is applied and the laser beam is irradiated from the laser oscillator, only the laser beam that has passed the sign passes through the polarizing plate,
The workpiece is illuminated and the reference mark is engraved. However, there are cases where this marking can be made clear and cases where it cannot be made clear. As a result of various studies by the present inventors on the cause, the following has been found. FIG. 7 shows the operation state of the liquid crystal element 13. FIG. 7A shows a case where no voltage is applied, and the liquid crystal molecules 13 are not applied.
Is in a twisted state between the electrodes 13A. Therefore, the incident linearly-polarized (for example, P-polarized) laser light 12A is converted into a linearly-polarized laser light 12B whose polarization plane is rotated by 90 degrees.
And eject.

[Problems to be solved by the invention]

In FIG. 7B, the liquid crystal power switch 25 is closed and the power
This shows a state where a voltage of 29 is applied between the electrodes 13A. The liquid crystal molecules 13B are in a so-called operating state extended in the direction of the electric field E. In this state, the polarization plane of the laser beam 12A does not rotate,
Pass as it is. Since the response time from when the power switch 25 is closed to when the liquid crystal molecules enter the operating state and the time to return from the operating state to the original twisted state depend on the type of liquid crystal molecules, it takes 0.2 to 0.5 seconds. When the laser beam 12A is irradiated over the laser beam, the laser beam 12A is emitted as elliptically polarized light. Then, a part of the laser beam 12A that should pass through is intercepted by the polarizing plate disposed thereafter, so that the amount of light decreases, and a clear code cannot be imprinted on the workpiece. Further, no consideration has been given to engraving desired pattern information corresponding to the moving workpiece. SUMMARY OF THE INVENTION An object of the present invention is to make it possible to clearly mark the same information on a moving workpiece without replacing a liquid crystal mask on a large number of workpieces, so that a laser marker with improved marking work efficiency and It is to provide a laser oscillator utilizing the same. Another object of the present invention is to provide a laser marker suitable for product management that can accurately mark the same location on a large number of moving workpieces.

Means for Solving the Problems] controller in the laser marker of the present invention, the operating time t ₄ of the liquid crystal mask displays information, holds at least one pulsed laser beam irradiation time t ₂ or more, pulsed laser beam during the 'irradiates a plurality of times to the liquid crystal mask at intervals, t ₁ downtime' stop time t ₁ is controlled to be a relationship between the irradiation time t ₂ and to t ₁ '> t _2. [Effect] In the former case, the stop time is maintained even when the liquid crystal mask is repeatedly irradiated with the pulse laser beam a plurality of times because of the relationship of t ₁ ′> t ₂
t ₁ ′ is longer than irradiation time t ₂ , during which time the liquid crystal mask is cooled to suppress the deterioration of the electro-optical characteristics of the liquid crystal mask due to temperature rise, and the same information can be clearly seen without replacing the liquid crystal mask A large number of engraved workpieces can be processed, and the engraving efficiency has been significantly improved. Also, in the latter, when the laser beam irradiation position is reached, desired information can be accurately engraved on the same place of a plurality of workpieces, and an engraving suitable for management of a large number of workpieces can be performed. Became.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. 1 and 3. FIG. For example, a P-polarized light 12A of a pulsed laser beam 12 from a solid-state laser represented by a pulsed laser oscillator 11 such as YAG
Illuminates the liquid crystal element 13. When a voltage is applied to the electrode 13A, the liquid crystal element 13 displays pattern information, for example, reference numeral 6 on the display unit 13D. In this state, when the P-polarized light 12A irradiates the display unit 13D,
The polarized light 12A passes through the code 6 as it is, but the P-polarized light 12A passing through other than the code 6 passes as the S-polarized light 12B having a 90 ° polarization plane. These polarized lights irradiate the polarizing plate 14. S-polarized light 12
B is reflected by the polarizing plate 14 and absorbed by the absorbing plate 15. The P-polarized light 12A that has passed through the polarizing plate 14 is
, The reference numeral 6 is stamped on the electronic component 17 which is the workpiece. Although not shown, the electronic component 17 is moving in the arrow direction Y on a belt conveyor. The synchronization timing between the P-polarized light 12A and the electronic component 17 is performed by the control unit 20 shown in FIG. The control unit 20 is configured as follows. The control console 21 has an operation unit 21A and a display unit 21B.
When reference numeral 6 is input at 21A, reference numeral 6 is displayed on the display section 21B, and this input signal flows to the exciting coil 23, the first timer 24, and the second timer 28. When the exciting coil 23 is excited, the liquid crystal power switch 25 is closed. One liquid crystal power switch 25 is attached to each segment 13S of the liquid crystal element 13. When the liquid crystal power switch 25 is closed and an applied voltage V shown in FIG. The liquid crystal element 13 is driven via a liquid crystal operation circuit 31 described later. As shown in FIGS. 7A and 7B, the liquid crystal element 13 applies a voltage V between the electrodes from the non-voltage state in which the liquid crystal molecules 13C are twisted to the operation state in which the liquid crystal molecules 13B are arranged in one direction. Become. Time for maintaining the operating state is the operating time t ₄ as shown in FIG. 3 (b). Response time t ₃ is the time until the state of the liquid crystal molecules of a liquid crystal molecules 13C to the liquid crystal molecules 13B. Recovery time t ₅ is the time from the liquid crystal molecules 13B until returning to the liquid crystal molecules 13C. The first timer 24 is not operated during the return time t ₅ the response time t _3, operates only when the operation time t _4. Laser switch
When 26 is closed, a voltage is applied between electrodes (not shown) of the pulse laser oscillator 11 by a pulse power supply 27 via a laser operation circuit 32 shown in FIG. irradiated by the irradiation time t ₂ shown in (d). The second timer 28 and the operation only irradiation time t _2, the stop time
No operation is performed at t ₁ and t ₁ ′. When the second timer 28 operates, the holding circuit 30 provided between the control console 21 and the liquid crystal power switch 25 operates, and the operation will be described later. Next, the operation of the control unit 20 will be described. An input signal corresponding to reference numeral 6 is input from the operation unit 21A,
The operation input contacts 31A and 31B are closed. Although the first timer 24 is stopped or delayed, the exciting coil 23 is excited, the auxiliary contact 23A is closed, and the first exciting coil 33 on the liquid crystal side is excited, so that the liquid crystal power switch 25 is closed. An applied voltage (V) shown in FIG. 3 (a) is applied to the liquid crystal element 13. The liquid crystal element 13 applies the applied voltage (V) from the no-voltage state and responds
Operations When the time t ₄ through t _3, the liquid crystal molecules 13B is in the operating state. In this state, the first timer 24 operates, and the auxiliary contact 24A
Is closed, the second excitation coil 36 on the laser side is excited, the laser switch 26 is closed, and a pulse voltage is applied to the pulse laser oscillator 11 from the pulse power supply unit 27. The P-polarized light 12A generated by the pulse laser oscillator 11
The liquid crystal element 13 as shown in (d) of FIG irradiated by the irradiation time t _2. As a result, the laser light passing through the liquid crystal portion to which the voltage is applied is extracted as linearly polarized light (P-polarized light), so that a clear code 6 can be imprinted on the electronic component 17, and the yield of the imprint of the electronic component 17 can be reduced. Significantly improved. Thus, the present invention irradiates the operation time by operating to delay than the operation time of the liquid crystal power switch 25, P-polarized light 12A when the liquid crystal element 13 is fully operating time t ₄ of Rezasuitsuchi 26 in the first timer 24 since the structure as to be, is not occur conversion into linear polarization → elliptical polarization as in the case of P-polarized light 12A in response time t ₃ or recovery time t ₅ is irradiated. As a result, the intensity of the laser beam does not decrease, and a clear code 6 can be imprinted on the electronic component 17, so that the yield of the imprint of the electronic component 17 can be improved. This means that the response time t ₄ and the recovery time t ₅ of the liquid crystal molecules accompanying the rewriting operation of the pattern information displayed on the liquid crystal
This is because the laser beam 12A is controlled to be non-irradiated. In the above-described embodiment, the laser switch 26 is delayed by the first timer 24. However, after the liquid crystal power switch 25 is manually closed without using the first timer 24, the operation time t ₄
The laser switch 26 may be closed while holding the switch. After that, after cutting off the input signal of the operation unit 21A, a different code is input again from the operation unit, and if the same operation as described above is performed, the different code can be clearly engraved on the electronic component.
A different code corresponding to the electronic component 17 can be continuously imprinted on the electronic component 17. On the other hand, when the same code and, for example, 6 are engraved on a large number of electronic components 17, when the code 6 is input by the operation unit 21A, the holding circuit 30 indicated by a chain line operates and the holding contacts 30A and 30B are closed.
The second timer 28 is stopped. The first excitation coil 33 is excited to close the liquid crystal power switch 25, the liquid crystal element 13 comes to operating state of maintaining the operating time t ₄ when shown in FIG. 3 (c),
When the second timer 28 operates and closes the auxiliary contact 28A,
After the same manner as described above irradiated P-polarized light 12A only the irradiation time t _2, the second
The timer 28 stops for the time t ₁ ′, and then the second timer 28
By repeating the operation of performing the operation again, the electro-optical characteristics of the liquid crystal mask 13 are not degraded because of the relationship of t ₁ ′> t ₂ even if the pulse laser beam is repeatedly irradiated on the liquid crystal mask 13 a plurality of times. The stop time t ₁ ′ is longer than the irradiation time t ₂ , and the liquid crystal mask 13 is cooled to increase the temperature of the liquid crystal mask.
Thus, it is possible to process a large number of workpieces on which the same information is clearly imprinted without replacing the liquid crystal mask 13, thereby significantly improving the engraving work efficiency.

3. An electronic component 17 traveling in a direction indicated by an arrow Y in this embodiment.
It is necessary to irradiate the P-polarized light 12A with a laser beam irradiation position X _1. The combined from the position X ₂ to time t _3, t ₅ or time t _1, t ₁ 'when moving the laser beam irradiation position X _1, by adjusting the speed of the arrow direction Y for example a belt conveyor, a pulse is above time The laser oscillator 11 uses the stop time during which it is stopped, without reducing the efficiency of the engraving work,
There is an advantage that the stamping operation can be performed accurately. This is a state where the electronic component 17 by the laser beam irradiation position X ₁ is stopped temporarily, when irradiated with P-polarized light 12A, the time other than the irradiation time t2 t _1, t ₁ ', stops at t _3, t ₅ like,
By adjusting the speed of Y and the time of each timer, the efficiency of the engraving operation can be increased. By adjusting the time of each timer, it is possible to accurately manage a large number of electronic components in which desired pattern information corresponding to a large number of moving electronic components is continuously imprinted. Also when the electronic component 17 is irradiated on the electronic component 17 with the laser beam at the laser beam irradiation position X ₁ after a predetermined time from the time of passing through the position X _2, be engraved accurately pattern information in the same location of the large number of electronic components 17 As a result, the yield of the electronic component 17 on which pattern information is imprinted is significantly improved.

FIG. 4 shows a liquid crystal element 13 having a liquid crystal operation display section 40, a reference light 41 and a detector 42 connected to the liquid crystal operation display section, and a transmission of the reference light 41. The transmission amount of the reference light is related to the response time of the liquid crystal mask 13. That is, if the transmission amount is large, the temperature is high, the response time of the liquid crystal mask 13 is fast, and if the transmission amount is small,
Contrary to the above, the control console 21 corrects the change in the response time of the liquid crystal mask 13 so that the response time becomes a predetermined response time.
Even if the response time of 13 changes, this is detected by the detector 42,
Correction by the control console 21 makes it possible to imprint the pattern information on the workpiece with a constant transmission amount.

5. Embodiment 5 In the embodiment shown in FIGS. 5 and 6, a liquid crystal element 13 and a polarizing plate 14 are arranged in a solid-state laser oscillator 47. FIG. P-polarized light 12 generated by exciting laser rod 43 with excitation lamp 44
A is a P-polarized light 12A of a laser beam partially including (including) the pattern information of the liquid crystal display element 13 by the liquid crystal display element 13, and the rest is not including (not including) the pattern information obtained by rotating the polarization plane by 90 °. The light is converted to S-polarized light 12B. Both are separated by a polarizing plate 14, and the P-polarized light 12A forms an image on an electronic component 17 by an image forming optical system 16 and performs marking. On the other hand, the S-polarized light 12B is reflected by the reflecting mirror 46, travels through the polarizing plate 14 in the opposite direction, is converted from S-polarized light to P-polarized light by the liquid crystal element 13, reaches the total reflecting mirror 45 via the laser rod 43, and is folded back. After being amplified, it goes to the liquid crystal element 13. In this embodiment, both ends of the excitation lamp 44 and the liquid crystal element 13 are connected to the control unit 20 having the same structure as that shown in FIGS. The embodiment shown in FIG. 6 is a modification of FIG. 5 in which the arrangement of the reflecting mirror 46, the focusing system 16, and the electronic components 17 is exchanged, and the total reflecting mirror 45 and the reflecting mirror 46 are aligned. , Optical adjustment becomes easy. As described above, in the configuration of FIGS. 5 and 6, an optical resonator is constituted by the optically facing reflecting mirror 46 and the total reflecting mirror 45 with the laser rod 43 interposed therebetween, and has not been used until now. Since the S-polarized light 12B is returned to the laser rod 43,
Significantly reduces the low utilization rate of laser light, which is a drawback of masked laser markers (usually 20 to 30% of the light emitted from the laser device is used for marking, and the rest is lost due to scattered heat, etc.) Can be improved.

【The invention's effect】

As described above, according to the laser marker of the present invention, even when the liquid crystal mask 13 is repeatedly irradiated with the pulse laser beam a plurality of times, the stop time t ₁ ′ is longer than the irradiation time t ₂ and the liquid crystal mask 13 is cooled. As a result, the deterioration of the electro-optical characteristics of the liquid crystal mask 13 due to the temperature rise is suppressed, and it is possible to process many products with the same information clearly engraved without replacing the liquid crystal mask 13, and the engraving work efficiency Significantly improved. In addition, it is possible to accurately imprint the same location on a large number of products, and the yield of products on which information is imprinted is significantly improved.

[Brief description of the drawings]

FIGS. 1 and 2 are schematic explanatory diagrams and an equivalent circuit diagram of a laser marker according to an embodiment of the present invention, FIGS. 3 (a) to 3 (d) are operating characteristic diagrams of FIGS. 1 and 2, and FIG. FIGS. 6 to 6 are schematic explanatory views of a laser marker according to another embodiment of the present invention, and FIGS. 7 (a) and 7 (b) are operational explanatory views of a conventional liquid crystal element. 11 ... pulse laser oscillator, 13 ... liquid crystal element, 24 ... first timer, 25 ... liquid crystal power switch, 26 ... laser switch.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-38888 (JP, A) JP-A-62-24884 (JP, A) JP-A-61-108488 (JP, A)

Claims (5)

(57) [Claims] 1. A laser marker which irradiates a laser beam from a laser oscillator onto a liquid crystal mask and transfers information displayed on the liquid crystal mask onto a workpiece. A control unit for controlling the beam and the operation time t of the liquid crystal mask displaying the information.
_4, retains at least one pulse laser beam irradiation time t ₂ or more, pulsed laser beam stop time t ₁ 'therebetween
A laser marker that irradiates the liquid crystal mask a plurality of times at intervals of, and controls the relationship between the stop time t ₁ ′ and the irradiation time t ₂ such that t ₁ ′> t ₂ . 2. A laser marker for irradiating a laser beam from a laser oscillator onto a liquid crystal mask and transferring information displayed on the liquid crystal mask onto a workpiece, wherein a switch for controlling the laser beam from the laser oscillator is provided. and a liquid crystal power switch for controlling the pattern display of the liquid crystal mask, a holding circuit for holding the operating voltage of the liquid crystal power switch at least one pulse laser beam irradiation time t ₃ or more, the pulsed laser beam while holding circuit is operating Stop time t ₁ ′
And a control unit for controlling the relationship between the stop time t ₁ ′ and the irradiation time t _{2 so} that t ₁ ′> t _2. Laser marker. 3. A laser marker for irradiating a laser beam from a laser oscillator onto a liquid crystal mask and transferring the information displayed on the liquid crystal mask onto a workpiece. a control unit for controlling the beam is provided, a laser beam to the controller workpiece by the laser beam irradiation position X ₁ after a predetermined time from the time at which the workpiece is conveyed has passed the position X ₂ by the conveying unit A laser marker characterized in that the laser marker is controlled to be controlled. 4. A laser marker for irradiating a laser beam from a laser oscillator onto a liquid crystal mask and transferring information displayed on the liquid crystal mask onto a workpiece, irradiating a part of the liquid crystal mask with reference light, A laser marker comprising means for detecting a change amount of transmitted reference light and determining a pattern display capability of the liquid crystal mask. 5. An optical resonator comprising a pair of reflecting mirrors facing each other with a laser rod interposed therebetween, and an optical resonator disposed between the laser rod and one of the pair of reflecting mirrors on a workpiece. A liquid crystal mask to which information to be transferred is given; a "present" laser beam including pattern information transmitted through the liquid crystal mask indicating the information displayed on the liquid crystal mask; and an "absent" laser beam including no information. With a polarizing plate to distinguish,
A laser oscillator used as a laser marker, wherein a polarizing plate takes the former laser light out of the optical resonator and returns the latter laser light into the optical resonator.