JP2001071159A - Laser joining method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the stoppage of processing with the least possible necessary output, to minimize the deformation and change of properties of peripheral parts and upper and lower films by heat input of the laser and to rapidly complete joining by finely fragmenting laser energy to plural pulse shots and stopping the irradiation with a laser when needed by judgment from a processing state. SOLUTION: The energy of the irradiation with the respective pulses according to the number of irradiation times is regulated by using the laser joining device in such a manner that the total sum of the energy of the irradiation with the pulses of the predetermined number of times attains the energy predicted to be required for melting and joining the plural electrode patterns and attains the threshold value which is the energy on the verge as to whether melting progresses or not after the prescribed number of times. The joining state of the irradiated parts is observed from the side opposite to the irradiation after the irradiation with the respective pulses and whether the electrode patterns are joined or not is detected. When the pattern are joined, the irradiation with the pulses of the energy regulated according to the number of irradiation times is executed. The irradiation with the pulses is stopped when the patterns are joined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser bonding method and apparatus, and more particularly to a laser bonding method for performing laser bonding between a defective circuit and a redundant circuit provided to relieve a broken wiring in a liquid crystal panel or the like. And an apparatus.

[0002]

2. Description of the Related Art A conventional laser bonding method of this type is, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-319438, for example, in which a defective wiring such as a liquid crystal panel and a redundant circuit are laser-bonded. It is used for FIG. 4 is a plan view showing an example of the liquid crystal panel. In liquid crystal panels,
As shown in FIG. 4, a redundant circuit 5 is provided below the signal wiring 4 in advance. If there is a broken portion 6 in the signal wiring 4, a laser spot is radiated from above the signal wiring 4 to the overlapping portion 7 where the redundant circuit 5 and the remaining signal wiring 4 that has not been broken are overlapped. The disconnection of the signal wiring 4 is corrected by welding and electrically connecting the signal wiring 4 to the signal wiring 5.

[0003] In the conventional laser joining method, in the laser joining of a redundant circuit of a liquid crystal panel, a method of irradiating a pulse laser only for one shot has been mainly used.

[0004]

However, since laser bonding is thermal processing, thermal deformation and thermal deterioration around the bonding portion or the upper and lower films are unavoidable. Energy input is most ideal. Therefore, due to factors not taken into account at the time of calculation,
If the calculated laser output is actually too large, the method of irradiating only one shot cannot stop processing with a laser output equal to or less than the calculated laser output when necessary, judging the processing state.

According to the present invention, laser energy can be divided into a plurality of pulse shots, and laser irradiation can be stopped when necessary according to the processing state, so that processing can be stopped with a minimum required laser output. An object of the present invention is to provide a laser bonding method and apparatus capable of minimizing deformation and deterioration of a peripheral portion and upper and lower films due to laser heat input and completing laser bonding quickly.

[0006]

According to the laser bonding method of the present invention, the total energy of pulse irradiation of a predetermined number of times performed on an overlapping portion of a plurality of electrode patterns arranged to be overlapped inside the substrate is reduced. The energy required to melt and join the plurality of electrode patterns is required, and after the predetermined number of times, the energy is on the verge of whether or not the fusion proceeds. The energy of each pulse irradiation corresponding to the number of irradiations is defined so as to be a threshold value, and a laser beam is irradiated to a portion to be joined with the specified energy, and after each pulse irradiation, the irradiation is performed from the side opposite to the irradiation. Observes the joining state of the parts to detect whether or not they have joined, and when not joining, performs pulse irradiation with the prescribed energy according to the number of irradiations and joins To stop the pulse irradiation.

According to the present invention, the total energy of the pulse irradiation of a predetermined number of times is set to be the energy expected to be required for melting and joining the plurality of electrode patterns, and After a predetermined number of times, by defining the energy of each pulse irradiation according to the number of times of irradiation so as to be a threshold value which is the energy of the brink of whether or not the fusion proceeds, at the time of the end of the joining Heat storage can be reduced to prevent thermal deterioration and deformation around the joint, and the energy value of each pulse shot is specified to be high up to a predetermined number of irradiations, so joining is completed quickly it can.

In the above invention, it is preferable to observe the bonding state of the irradiating portion from the irradiation side after each pulse irradiation and before determining the bonding state of the irradiating portion from the side opposite to the irradiation. If it is determined whether or not bonding has been performed from the irradiation side, and if bonding has not been performed from the side opposite to the irradiation, pulse irradiation of the threshold value is performed regardless of the number of irradiations.

According to the present invention, even when the energy required for joining is less than expected, the energy of the pulsed laser beam can be reduced at a point in time before the joining is completely completed. The amount of heat stored in the fuel cell can be reduced.

Further, in the above invention, the sum of the energy of the pulse irradiation until the completion of the bonding is calculated, and each pulse is calculated so that the total of the energy of the pulse irradiation of a predetermined number of times becomes the total of the energy. Calibrate the specification of irradiation energy.

According to the present invention, the regulation of the energy is calibrated from the sum of the energy of the pulsed laser light.
The possibility that the joining is completed at the final pulse shot is increased, and if the energy required for the joining is larger than expected, it is possible to prevent the pulse laser beam from being continuously irradiated with the threshold value, and the joining can be completed quickly. In addition, when the energy required for joining is smaller than expected, the energy of the pulse laser beam immediately before joining is high and the amount of heat stored at the time of joining completion is prevented from increasing, and thermal deterioration and deformation around the joint are not caused. You can do so.

[0012]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the laser welding apparatus according to the present invention.

The liquid crystal panel 1 to be laser-joined is
It is held and fixed to a liquid crystal panel stage 3 on the XY stage 2. In the liquid crystal panel 1, as shown in FIG. 4, a redundant circuit 5 is provided so as to overlap with each signal wiring 4, and the signal wiring is disconnected and overlaps both of the divided portions 6. At least one joining position is set for each overlapped portion 7, and laser joining is performed at that position to repair disconnection of the signal wiring.

The control unit 8 moves the XY stage 2,
Positioning is performed so that the laser beam is applied to the laser bonding position set in the overlapping area of the signal wiring 4 of the liquid crystal panel 1 and the redundant circuit 5.

The pulsed laser light emitted from the laser oscillator 9 passes through a lens 10, an optical slit 11, and a lens 12, then passes through an optical mirror 13, an optical lens 14 for condensing the pulsed laser light, and a liquid crystal panel. An image is formed at one laser bonding position.

An image from the periphery of the processing mark and the upper surfaces of the upper and lower wiring layers when the laser light is irradiated is transmitted through the optical lens 14, the optical mirrors 13, 15 and the optical lens 16 to the camera
Caught at 7. Illuminator 18 for imaging by camera 17
Thereby, the upper surface of the liquid crystal panel 1 is illuminated. Camera 1
The video information from 7 is input to the junction detector 19 to determine whether or not it has penetrated the redundant circuit, and the junction detector 19 performs the determination, and the determination result is output to the control unit 8 one by one. Similarly, images from the periphery of the processing mark and the lower surface of the upper and lower wiring layer films are formed by the optical lens 20,
The image is captured by a camera 23 via an optical mirror 21 and an optical lens 22. The illumination device 24 illuminates the lower surface of the liquid crystal panel 1 for imaging by the camera 23. The video information from the camera 23 is input to the joint detector 25, which determines whether or not the redundant circuit 5 has penetrated, and outputs the determination result to the control unit 8.

As the pulsed laser light is continuously irradiated at predetermined time intervals, the joint of the redundant circuit 5 to which the pulsed laser light is irradiated is melted, the melted portion gradually spreads to the periphery, and the through hole is formed. It is formed. At this time, since the melting of the pattern on the opposite side progresses later than the irradiation side, it is delayed from the camera 23 on the opposite side after detecting that the processing mark has reached a sufficient size as viewed from the camera 17 on the irradiation side. It is detected that the processing mark has reached a sufficient size, and bonding is detected.

The laser controller 26 controls the timing at which pulse laser light is output from the laser oscillator 9 and the energy value of each pulse laser light based on a command from the control unit 8. In addition, an energy change function that gives the absolute energy value of the pulsed laser beam using the number of shots as a parameter is set in advance. Further, the laser controller 26 determines whether or not the fusion of the junction of the redundant circuit 5 proceeds from the state where the junction between the signal wiring 4 and the redundant circuit 5 is detected by the junction detector 19, based on the energy value at the brink of whether or not the fusion is progressed. A threshold value indicating a certain minimum laser energy is stored. The energy value of each pulsed laser beam is controlled based on these.

FIG. 2 is a diagram showing an example of a change in the laser energy of the laser oscillator 9 based on a command from the laser controller 26 in FIG. The change in the laser energy of each pulse shot that is sequentially applied to the joint is such that the energy required for the joint is reduced rapidly as approaching the final pulse shot, and the energy value of the final pulse shot. Is described as an exponential function so as to be a threshold value which is an energy value on the brink of whether or not the laser bonding is performed. In addition, the number of pulse shots to be applied before the completion of the irradiation of the energy expected to be required for bonding is set to fifteenth, and the energy is changed so that the threshold value is applied immediately after the last pulse shot. If the number of pulse shots is increased, the processing time is increased. If the number is reduced, the energy per pulse is increased, and there is a possibility that an excess energy is applied more than the minimum energy required to advance the bonding. It is desirable to set the number of pulse shots to be irradiated until the irradiation of the energy expected to be required for bonding is completed, for example, from 10 to 20.

The threshold value is assumed to correspond to 40% with the first shot as a relative value of 100%. This setting has a similar meaning to the setting of the number of pulse shots. If the energy of the first shot is close to the threshold value, the number of shots increases, and the processing time increases. If the energy of the first shot is increased as compared with the threshold value, the energy per pulse becomes large. May increase. The first shot has a relative value of 10
Desirably, the threshold value is set to a value corresponding to 30 to 50% as 0%.

Next, the operation of laser bonding according to this embodiment will be described.

FIG. 3 is a flowchart showing the operation of the laser joining of FIG.

First, an energy change function that determines the energy value of the pulsed laser beam in each shot in accordance with the number of shots of the pulsed laser beam, and a threshold that is the energy value on the verge of whether or not laser bonding is performed. The value is set in advance (step S1). Further, all the laser bonding positions of the liquid crystal panel set on the stage 3 are input. Then, the XY stage 2 is moved to adjust the laser irradiation position to the first laser bonding position (Step S2).

When the joining is started, the number of shots N is set to 1 (step S3), and an energy value corresponding to the number of shots N is calculated based on the energy change function (step S4), and the calculated energy is calculated. The pulsed laser beam of the value is applied to the laser joint of the liquid crystal panel 1 (step S5). When the calculated energy value becomes equal to or smaller than the threshold value, the energy value of the pulse laser beam is set as the threshold value. When N is 2 or more, the pulsed laser light of the previous time, that is, the irradiation of the pulsed laser light of the (N-1) th shot,
The pulsed laser light is emitted at a timing when a preset time has elapsed.

After the pulse laser irradiation, first, image information of the spot-shaped pulse laser beam irradiation site is input from the laser irradiation surface side camera 17 to the joint detector 19, and the joint detector 19
Then, the processing mark size of the spot-shaped pulsed laser beam irradiation site is compared with the reference value A, and it is determined whether bonding has been performed (step S6). If not, the number N of shots is incremented (step S7), and the process returns to step S4.

When the joining is determined in step S6, the image information of the spot-shaped pulsed laser beam irradiation part imaged by the camera 23 on the side opposite to the laser irradiation side is input to the joining detector 25. The processing mark size of the spot-shaped pulsed laser beam irradiation site is compared with the reference value B, and it is determined whether bonding has been performed (step S8). If the laser beam is not bonded after the pulse laser irradiation, a pulse laser beam having a threshold value is applied to the laser bonding position of the liquid crystal panel 1 (step S9), and bonding is further performed. The threshold value is an energy value at the brink of whether or not the joining is performed. Even if there is an error of ± several shots, it is difficult to cause thermal deformation and deterioration. After the irradiation, the process returns to step S8. When it is determined in step S8 that the laser beam has penetrated, the laser welding of that part is completed, and the total energy irradiated before the welding is calculated, and the energy is set so as to fall just below the threshold value with a preset number of shots. The change function is calibrated (step S10), and the calibrated energy change function is used for joining at the next joining position.

In the calibration of the energy change function, first, the total sum of the energies of the respective pulse laser beams until it is determined in step S6 that the laser beam has penetrated is calculated. Step S
In step 8, the sum of the energies of the pulsed laser beams irradiated until it is determined that the laser beam has penetrated is added to calculate the sum of the energy required for bonding. Then, a threshold value is obtained with a predetermined number of shots, and an energy change function is obtained in which the sum of the energies of the pulsed laser beams irradiated until the threshold value is reached becomes the above-described bonding energy.

Then, it is determined whether or not it is the last laser bonding position (step S11). If it is not the last, the XY stage 2 is moved so that the laser irradiation position matches the next laser bonding position (step S12). If it is the last laser bonding position in step S11, the operation of the laser bonding ends.

Next, a modification of the above embodiment will be described.

Since joining by laser heat input involves repetition of a heating process and a cooling process, the cooling phenomenon of the previous pulse shot overlaps with the heating phenomenon of the next pulse, and this overlap affects the joining quality. . In this modification, the energy change function is changed according to the set time interval in consideration of the influence on the joining quality due to the fact that the cooling phenomenon of the previous pulse shot overlaps with the heating phenomenon of the next pulse. That is, in the energy change function of FIG. 2, it is a function having two variables: the number of shots N and the time interval t of the pulsed laser light.

[0032] Thus, regardless of the setting of the time interval for irradiating the pulsed laser beam, damage around the joint can be reduced to a minimum.

Further, instead of setting the energy value according to the number of shots, a time interval change curve defining the pulse laser light irradiation time interval may be set to change the pulse laser light irradiation time interval. Good. In addition to setting the energy value according to the number of shots, a time interval change curve defining the pulse laser beam irradiation time interval may be set.

Thus, it is possible to prevent the energy of each pulsed laser beam from being set to an excessively large or small laser energy, to perform bonding with an appropriate output of a laser oscillator to be used, and to stably input the laser energy. Can control heat.

[0035]

As described above, according to the laser bonding apparatus of the present invention, it is expected that the total energy of the pulse irradiation of a predetermined number of times is required for melting and bonding a plurality of electrode patterns. The energy of each pulse irradiation according to the number of irradiations is specified so that the energy becomes a threshold value which is the energy at the brink of whether or not melting proceeds after a predetermined number of times. By doing so, it is possible to reduce the heat storage at the end of joining to prevent thermal deterioration and deformation around the joint, and to increase the energy value of each pulse shot up to a predetermined number of irradiations. The bonding can be completed promptly.

Further, the bonding state on the irradiation side and on the side opposite to the irradiation is monitored, and it is determined that bonding has been performed from the irradiation side. The pulse irradiation of the threshold value is performed.

According to the present invention, even when the energy required for bonding is less than expected, the energy of the pulsed laser beam can be reduced at a point in time before the bonding is completely completed. The amount of heat stored in the fuel cell can be reduced.

Further, the sum of the energy of the pulse irradiation until the joining is completed is calculated, and the regulation of the energy of each pulse irradiation is calibrated so that the sum of the energy of the pulse irradiation of a predetermined number of times becomes the sum of the energy. I do.

According to the present invention, the regulation of the energy is calibrated from the sum of the energies of the pulsed laser beams. Therefore, for example, when joining another portion with the same liquid crystal panel,
The possibility that the joining is completed at the final pulse shot is increased, and if the energy required for the joining is larger than expected, it is possible to prevent the pulse laser beam from being continuously irradiated with the threshold value, and the joining can be completed quickly. In addition, when the energy required for joining is smaller than expected, the energy of the pulse laser beam immediately before joining is high and the amount of heat stored at the time of joining completion is prevented from increasing, and thermal deterioration and deformation around the joint are not caused. You can do so.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a first embodiment of a laser bonding apparatus according to the present invention.

FIG. 2 is a diagram showing an example of a change in laser energy of a laser oscillator 9 of FIG.

FIG. 3 is a flowchart illustrating an operation of the laser bonding of FIG. 1;

FIG. 4 is a plan view showing an example of a conventional liquid crystal panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 XY stage 4 Signal wiring 5 Redundant circuit 6 Overlapping part 7 Disconnection part 8 Control part 9 Laser oscillator 10, 12, 14, 16, 20, 22, 22 Lens 11 Optical slit 13, 15, 21 Optical mirror 17, 23 Camera 18, 24 Illuminator 19, 25 Joint detector 26 Laser controller

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01S 3/00 H01S 3/00 B // B23K 101: 40

Claims (8)

[Claims] 1. A method according to claim 1, wherein a plurality of pulse irradiations of laser light performed on an overlapping portion of a plurality of electrode patterns arranged in the substrate overlap each other. The energy is expected to be required to fuse and bond the plurality of electrode patterns, and after the last pulse irradiation of the predetermined number of pulse irradiations, the melting does not proceed or not. The energy of each pulse irradiation according to the number of irradiations is defined so as to be a threshold value which is the energy on the brink of the sea, and the laser beam is pulse-irradiated to the part to be joined with the energy specified according to the number of irradiations, After each pulse irradiation, the joining state of the irradiation section is observed from the side opposite to the irradiation to detect whether or not joining has been performed. It is performed pulse irradiation of energy, laser bonding method is characterized in that to stop the pulse irradiation when joined. 2. After each pulse irradiation, and before observing the bonding state of the irradiating section from the side opposite to the irradiation, observe the bonding state of the irradiating section from the irradiation side to determine whether or not bonding has been performed. Detecting, detecting that the joint is seen from the irradiation side, and, when detecting that it is not joined from the side opposite to the irradiation, performs pulse irradiation of the threshold value regardless of the number of irradiation. The laser joining method according to claim 1, wherein 3. The energy of each pulse irradiation decreases rapidly as approaching the final pulse irradiation, and the energy of the last pulse irradiation is a threshold energy that indicates whether or not bonding proceeds. 2. The laser joining method according to claim 1, wherein an energy defining function that defines an energy value of each pulse irradiation is set to a hold value. 4. The method according to claim 1, further comprising: calculating a sum of energies of the pulse irradiations until the joining is completed, and defining the energy of each pulse irradiation so that the sum of the energies of the pulse irradiation of a predetermined number of times becomes the sum of the energies. 2. The laser joining method according to claim 1, wherein the laser beam is calibrated. 5. The laser joining method according to claim 3, wherein said energy defining function is an exponential function. 6. The laser welding method according to claim 3, wherein the pulse irradiation is performed at a preset time interval, and the energy defining function is set based on the time interval. 7. A laser irradiation section for emitting a pulsed laser beam, and a substrate having a plurality of electrode patterns to be joined, which are disposed in an overlapped manner, are held, and the pulsed laser beam is overlapped with the plurality of electrode patterns. A substrate moving unit that moves so as to adjust the irradiation position of the substrate, and detects whether or not bonding has been performed by observing the bonding state of the irradiation unit of the pulse laser light from the side of the substrate opposite to the side where the pulse laser light is irradiated And the detection unit, the energy of each pulse irradiation is rapidly reduced as the sum of the pulse irradiation energy from the first pulse irradiation approaches the final pulse irradiation that is the energy expected to be required for the bonding, and thereafter, after the final pulse irradiation Defines the energy value of each pulse irradiation in advance to a threshold value, which is the energy at the brink of whether or not welding proceeds, On the basis of the detection results obtained from the detection unit, to perform the pulse irradiation of defined depending on the number of times of irradiation energy to the laser irradiation unit when not bonded to,
And a control unit for stopping the pulse irradiation of the laser irradiation unit when the bonding is performed. 8. An irradiation side detection unit for observing a bonding state from an irradiation side of the substrate to which the pulsed laser light is irradiated and detecting whether or not bonding is performed, wherein the control unit is configured to detect the irradiation side. When it is detected that the bonding is not performed by the unit, the laser irradiation unit performs pulse irradiation of energy defined according to the number of irradiations, the bonding is detected by the irradiation side detection unit, and the detection unit When it is detected that the bonding is not performed, the laser irradiation unit is made to perform pulse irradiation of the threshold value regardless of the number of irradiations, and when it is detected that the bonding is performed by the irradiation side detection unit and the detection unit, the laser irradiation is performed. The laser welding device according to claim 7, wherein the pulse irradiation of the irradiation unit is stopped.