TWI843846B - Laser processing device - Google Patents

Abstract

In a laser processing device for processing a large object to be processed, in order to make the irradiation position and/or focus of the laser light irradiated from the irradiation unit to the object to be processed correctly aligned with the target position on the object to be processed, a laser processing device (1) is constructed to perform processing by irradiating the laser light (L) toward the target position on the object to be processed (O), which comprises: an irradiation unit (2) having an objective lens for focusing the laser light (L) toward the target position on the object to be processed (O); and a first XY A loading table (3) which can move at least the objective lens (24) of the aforementioned irradiation unit (2) relative to the object to be processed (O) in a two-dimensional direction which is orthogonal or substantially orthogonal to the laser light axis; and a second XY loading table (7) which can move the aforementioned irradiation unit (2) and the aforementioned first XY loading table (3) relative to the object to be processed (O) in a two-dimensional direction which is orthogonal or substantially orthogonal to the laser light axis, and the movable range in the two-dimensional direction is larger than that of the first XY loading table (3).

Description

Laser processing device

The present invention relates to a laser processing device for implementing processing by irradiating laser light toward a target position on a processed object.

As a type of laser processing device, there can be cited a laser repair device that irradiates defective (or defective) parts of a liquid crystal display module, a plasma display module, an organic EL (Electro-Luminescence) display module, an inorganic EL display module, a micro-LED display module, a transparent conductive film substrate, or a color filter with laser light (for example, refer to the following patent document).

In the case of laser repair equipment, it is required to use the defective part on the object to be processed as the target position and accurately irradiate the laser light to the target position. If the position of the irradiated laser light or the focus of the laser light deviates slightly from the target position, as long as the defective part cannot be properly corrected, it is very likely that the normal components or circuits adjacent to the defective part will be damaged.

The operation of the laser beam irradiation position on the object to be processed is usually performed through an XY stage. That is, the XY stage supports an irradiation unit having an objective lens that focuses the laser beam on the object to be processed, and the irradiation unit moves relative to the object to be processed in the X-axis direction and the Y-axis direction, thereby positioning the object so that the laser beam can irradiate the target position.

Recently, liquid crystal displays and the like, which are objects to be processed, have become significantly larger in size, and accordingly, the XY stage must also be larger in size.

However, the components of the large-scale XY stage are larger in size and weight, which leads to increased friction and backlash between the components, increased lost motion, and increased risk of the irradiation unit not reaching the correct position or slipping past the correct position.

Furthermore, in order to manipulate the focus of the laser light on the object to be processed, the irradiation unit having an objective lens for focusing the laser light on the object to be processed is moved in the Z-axis direction parallel or substantially parallel to the laser light axis through a screw feed mechanism or other adjustment mechanism.

Furthermore, it is conceivable to implement the following feedback control: a displacement meter (for example, see the following non-patent document) capable of accurately measuring the interval distance from the irradiation unit to the object to be processed is attached to the irradiation unit, and the position of the irradiation unit is adjusted along the Z-axis direction so that the interval distance measured by the displacement meter is consistent with the focal distance of the objective lens. As long as this is done, even if vibration and other disturbances are applied to the laser processing device during the process of irradiating the laser light, the focus of the laser light can be continuously aligned with the target position on the object to be processed.

However, large processed objects cannot avoid partial or total bending and deformation. Moreover, the position of the object lens of the irradiation unit in the processed object, that is, the position where the laser light emitted through the object lens hits the processed object, is inconsistent with the position of the distance between the displacement meter and the irradiation unit (offset). Therefore, it cannot be guaranteed that the interval distance measured by the displacement meter will be exactly the same as the distance from the object lens to the target position on the processed object. Moreover, the deviation between the two increases or decreases with the degree of bending and deformation of the processed object. [Prior technical literature] [Patent literature]

Patent document 1: Japanese Patent Publication No. 2005-274709 [Non-patent document]

Non-patent document 1: “Laser displacement meter | KEYENCE (registered trademark)”, [online], 2011, [retrieved on June 26, 2011], Internet https://www.keyence.co.jp/products/measure/laser-positioning/

[The problem the invention is trying to solve]

The present invention is intended to accurately align the irradiation position and/or focus of the laser light irradiated from the irradiation unit to the object to be processed with the target position on the object to be processed in a laser processing device for processing a large object to be processed. [Means for solving the problem]

The present invention is a laser processing device for performing processing by irradiating a target position on an object to be processed with laser light, and comprises: an irradiation unit having an objective lens for focusing the laser light toward the target position on the object to be processed; and a first XY stage, which can move at least the objective lens of the irradiation unit relative to the object to be processed in a two-dimensional direction that is orthogonal or substantially orthogonal to the axis of the laser light; and a second XY stage, which can move the irradiation unit and the first XY stage relative to the object to be processed in a two-dimensional direction that is orthogonal or substantially orthogonal to the axis of the laser light, and the movable range in the two-dimensional direction is larger than that of the first XY stage.

That is, the present invention makes the second XY stage responsible for the task of moving the irradiation unit in a large scale corresponding to the large-scale processed object, and makes the first XY stage responsible for the task of finely and precisely adjusting the position of the irradiation unit, especially the objective lens. More specifically, the laser light is irradiated to the processed object while the following control is performed, and the control is that after the irradiation position of the laser light irradiated to the processed object by the irradiation unit through the objective lens is positioned at the target position on the processed object or its vicinity by the second XY stage, the objective lens of the irradiation unit is maintained by the first XY stage so that the irradiation position of the laser light is aligned with the target position.

Preferably, the irradiation unit has a camera sensor that photographs a portion of the object to be processed through the objective lens, and performs the following feedback control: based on the image photographed by the camera sensor, the deviation between the current position of the objective lens and the position of the objective lens when the irradiation position of the laser light is aligned with the target position is detected, and in order to reduce the deviation, the position of the objective lens of the irradiation unit is adjusted by the first XY stage.

As long as there is a Z-axis adjustment mechanism that can move at least the objective lens of the aforementioned irradiation unit relative to the object to be processed in a direction parallel or approximately parallel to the laser light axis, the focus of the laser light emitted from the objective lens can be correctly aligned with the target position on the object to be processed by the function of the Z-axis adjustment mechanism.

In a factory or other site where the laser processing device is installed and used, vibration may sometimes be generated on the floor surface due to a trolley or forklift driving around. For this reason, it is preferable to use a vibration-proof (or vibration-damping) member for suppressing vibration with a frequency higher than a predetermined value from being transmitted from the floor surface to the stage, and the member is interposed between the stage supporting the object to be processed, the irradiation unit, the first XY stage, and the second XY stage, and the floor surface.

Furthermore, the present invention is a laser processing device for processing by irradiating a laser beam toward a target position on a processed object, and comprises: an irradiation unit having an objective lens for focusing the laser beam toward the target position on the processed object; and a Z-axis adjustment mechanism, which can move at least the objective lens of the irradiation unit relative to the processed object in a direction parallel or substantially parallel to the laser beam axis; and a displacement meter, which measures the distance from the irradiation unit to the processed object; while performing feedback control, the laser beam is directed to the target position on the processed object; and the Z-axis adjustment mechanism can move at least the objective lens of the irradiation unit relative to the processed object in a direction parallel or substantially parallel to the laser beam axis; and the displacement meter can measure the distance from the irradiation unit to the processed object; and the displacement meter can adjust the laser beam to the target position on ... Light is irradiated onto the object to be processed. The feedback control is performed by positioning the irradiation unit in a manner that the focus of the laser light irradiated onto the object to be processed through the objective lens is aligned with the target position on the object to be processed without relying on the displacement meter. After the distance from the irradiation unit to the object to be processed is measured by the displacement meter and the distance is set to the target distance, the position of the objective lens of the irradiation unit is adjusted by the Z-axis adjustment mechanism in order to reduce the deviation between the distance currently measured by the displacement meter and the target distance.

More specifically, the irradiation unit has a camera sensor that photographs a portion of the object to be processed through the objective lens, and based on the image photographed by the camera sensor, after the irradiation unit is positioned in such a way that the focus of the laser light irradiated on the object to be processed through the objective lens is aligned with the target position on the object to be processed, the distance from the irradiation unit to the object to be processed is measured by the displacement meter, and the distance is set to the target distance.

As long as an XY stage is provided that can move at least the objective lens of the irradiation unit relative to the object to be processed in a two-dimensional direction that is orthogonal or substantially orthogonal to the laser light axis, the irradiation position of the laser light emitted from the objective lens can be accurately aligned with the target position on the object to be processed by the function of the XY stage. In this case, after the irradiation unit is positioned by the XY stage in such a manner that the irradiation position of the laser light irradiated on the object to be processed is aligned with the target position on the object to be processed, and after the irradiation unit is positioned by the Z-axis adjustment mechanism in such a manner that the focus of the laser light is aligned with the target position on the object to be processed, the distance from the irradiation unit to the object to be processed is measured by the displacement meter, and the distance is set to the target distance.

In the factory where the laser processing device is installed and used, vibration may be generated on the floor surface due to the movement of a trolley or a forklift around. For this reason, it is preferable to use a vibration-proof (or vibration-damping) member for suppressing the vibration with a frequency higher than a predetermined value from being transmitted from the floor surface to the platform, and the member is interposed between the platform supporting the object to be processed, the irradiation unit, the Z-axis adjustment mechanism and the displacement meter and the floor surface.

This laser processing device can be preferably used as a laser repair device for irradiating defective parts of a liquid crystal display module, a plasma display module, an organic EL display module, an inorganic EL display module, a micro-luminescent diode display module, a transparent conductive film substrate or a color filter with laser light. [Effect of the invention]

According to the present invention, in a laser processing device for processing a large object to be processed, the irradiation position and/or focus of the laser light irradiated from the irradiation unit to the object to be processed can be accurately aligned with the target position on the object to be processed.

One embodiment of the present invention is described with reference to the drawings. The laser processing device 1 of the present embodiment refers to a laser repair device that irradiates laser light L to a defective (or defective) portion of a processed object O such as a liquid crystal display module, a plasma display module, an organic EL display module, an inorganic EL display module, a micro-luminescent diode display module, a transparent conductive film substrate or a color filter and corrects the defective portion.

FIG1 shows the overall outline of the laser processing device 1. The main components of the laser processing device 1 include: an irradiation unit 2, which irradiates the laser light L toward the target position on the object O to be processed (i.e., the defective part of the liquid crystal display module, etc.); and XY stages 3, 7, which move the irradiation unit 2 in two-dimensional directions of the X axis and the Y axis that are orthogonal or substantially orthogonal to the optical axis of the laser light L; and Z-axis adjustment mechanisms 3, 6, which move the irradiation unit 2 in the Z-axis direction that is parallel or substantially parallel to the optical axis of the laser light L; and a displacement meter 4, which measures the distance from the irradiation unit 2 to the object O to be processed.

The stand 9 supports the irradiation unit 2, the XY stages 3 and 7, the Z axis adjustment mechanism 3 and 6, the displacement meter 4 and the object to be processed O. The stand 9 is grounded to the floor surface through the anti-vibration member 91. The anti-vibration member 91 is, for example, a passive suspension such as anti-vibration rubber or an air spring, and is used to suppress the vibration with a frequency higher than a predetermined value (for example, 5 Hz) from being transmitted from the floor surface to the stand 9.

The object O is fixed to the stage 9 by a clamp, suction or other appropriate means. While the object O is being irradiated with the laser light L, the object O is stationary.

The XY stages 3 and 7 in the laser processing device 1 are a combination of the first XY stage 3 and the second XY stage 7. The second XY stage 7 is installed on the frame 9 to support the irradiation unit 2, the first XY stage 3, the Z-axis adjustment mechanism 3 and 6, and the displacement meter 4, and can move these in two-dimensional directions in the X-axis direction and the Y-axis direction. The elements of the second XY stage 7 include, for example, a pair of Y-axis rails 71, which are mounted on both sides of the stage 9 and extend in the Y-axis direction; a pair of Y-axis linear motor carriages 72, which travel along each of the Y-axis rails 71; an X-axis rail 73, which has both sides supported by the Y-axis linear motor carriages 72 and extends in the X-axis direction; and an X-axis linear motor carriage 74, which travels along the X-axis rail 73. Then, the X-axis linear motor carriage 74 supports the irradiation unit 2, the Z-axis adjustment mechanism 3, 6 and the displacement meter 4. The irradiation unit 2 and the displacement meter 4 face the object O to be processed from directly above the object O in the Z-axis direction. Generally speaking, the second XY stage 7 causes the irradiation unit 2, the Z-axis adjustment mechanisms 3 and 6, and the displacement meter 4 to relatively displace the stage 9 and the object O in the X-axis direction and the Y-axis direction.

A linear encoder is attached to the set of the Y-axis track 71 and the Y-axis linear motor carriage 72, and the linear encoder is used to detect the position coordinates of the Y-axis direction of the Y-axis linear motor carriage 72. A linear encoder is also attached to the set of the X-axis track 73 and the X-axis linear motor carriage 74, and the linear encoder is used to detect the current position coordinates of the X-axis direction of the X-axis linear motor carriage 74. In short, the current XY position coordinates of the X-axis linear motor carriage 74 supporting the irradiation unit 2 are detected through two linear encoders.

The Z-axis adjustment mechanism 3, 6 in the laser processing device 1 is a combination of the first Z-axis adjustment mechanism 3 and the second Z-axis adjustment mechanism 6. The second Z-axis adjustment mechanism 6 is interposed between the housing 5 and the X-axis linear motor carriage 74, and can move the housing 5 relative to the X-axis linear motor carriage 74 in the Z-axis direction. The housing 5 is used to integrate the irradiation unit 2, the first XY stage 3 and the displacement meter 4. The height position of the X-axis linear motor carriage 74 in the Z-axis direction is constant. The second Z-axis adjustment mechanism 6 is, for example, a known screw feed mechanism including a ball screw, which is used to make the screw shaft be axially supported on one of the X-axis linear motor carriage 74 and the housing 5, and to fix a nut screwed with the screw shaft on the other side, and to drive the screw shaft by rotation by a servo motor or a stepping motor, so that the nut moves forward and backward along the screw shaft, and induces the housing 5 to move up and down in the Z-axis direction. The second Z-axis adjustment mechanism 6 causes the irradiation unit 2 and the displacement meter 4 to displace the gantry 9 and the object to be processed O relative to the Z-axis direction.

A linear encoder is attached to the combination of the X-axis linear motor carriage 74 and the housing 5, and the linear encoder is used to detect the current position coordinates of the housing 5 in the Z-axis direction.

FIG2 shows the structure of the irradiation unit 2 accommodated in the housing 5. The irradiation unit 2 includes: an optical system for observing the target position on the object O to be processed and its surrounding area; and an optical system for irradiating the target position on the object O to be processed with laser light L. The former optical system at least includes an incident illumination light source 21, a beam splitter (or half mirror) 22, a dichroic mirror 23, an objective lens 24, an imaging lens 251, and a camera sensor 25. The incident light supplied from the incident illumination light source 21 is reflected by the beam splitter 22 and turned to the direction of the optical axis of the objective lens 24 opposite to the object O to be processed. After passing through the dichroic mirror 23, the incident light passes through the objective lens 24 to illuminate the target position and the surrounding area on the object O to be processed. The light beam that hits the object to be processed and bounces back is incident on the objective lens 24, and passes through the dichroic mirror 23 and the beam splitter 22 and is incident on the imaging lens 251, and then forms an image on a solid-state imaging element such as a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) as the camera sensor 25. In this way, the camera sensor 25 can capture the target position and the surrounding area on the object O to be processed and obtain an image.

There are multiple types of objective lenses 24 with different magnifications. These objective lenses 24 are mounted on an electric revolver 241. By rotating the revolver 241, any objective lens 24 can be selected and arranged on the optical axis. In other words, the magnification of the applicable objective lens 24 can be changed.

The optical system of the latter includes at least an oscillator 26 as a light source of laser light L, an attenuator 27, a polarizer 28, a beam expander 29, a variable slit 20, a dichroic mirror 23, and an objective lens 24. The dichroic mirror 23 and the objective lens 24 are common to the optical system of the former. The laser light L supplied from the laser oscillator 26 is attenuated by the attenuator 27, polarized by the polarizer 28, and shaped by the beam expander 29 and the variable slit 20. The variable slit 20 can change the shape of the laser beam passing therethrough. Furthermore, the laser light L is reflected by the dichroic mirror 23 and turned in the direction of the optical axis of the objective lens 24 opposite to the object O. The laser light L is focused on the target position on the object O through the objective lens 24. In this way, the laser light L can be irradiated on the target position on the object O.

However, the former optical system and the latter optical system do not hinder other optical elements not shown in Figure 2, such as optical fibers or lenses, prisms, lenses, shutters, etc.

The displacement meter 4 is used to measure the interval distance along the Z-axis direction from the objective lens 24 of the irradiation unit 2 to the target position on the processed object O. The displacement meter 4 is, for example, a known laser displacement meter, which irradiates the laser light R toward the processed object O and precisely measures the distance from the displacement meter 4 to the processed object O by receiving the laser light R that hits the processed object O and bounces back. The displacement meter 4 is accommodated in the housing 5 or attached to the outside of the housing 5. Through the function of the second Z-axis adjustment mechanism 6 described above, the displacement meter 4 becomes one with the housing 5, the irradiation unit 2 and the first XY stage 3 and moves up and down in the Z-axis direction.

The first XY stage 3 is accommodated in the housing 5, and is used to support at least the objective lens 24 and the rotator 241 of the irradiation unit 2, and can move them in two-dimensional directions in the X-axis direction and the Y-axis direction. The first XY stage 3 is, for example, a known piezo stage, which can precisely move the stage supporting the objective lens 24 and the rotator 241 in the X-axis direction and the Y-axis direction by a piezo motor (ultrasonic motor). The first XY stage 3 is used to displace the objective lens 24 of the irradiation unit 2 in the X-axis direction and the Y-axis direction relative to the housing 5, and further relative to the stage 9 and the object O to be processed.

The first Z-axis adjustment mechanism 3 is also accommodated in the housing 5, and is used to support at least the objective lens 24 and the rotator 241 of the irradiation unit 2, and can move them in the Z-axis direction. The first Z-axis adjustment mechanism 3 is, for example, a known piezoelectric stage, which can precisely move the stage supporting the objective lens 24 and the rotator 241 in the Z-axis direction by a piezoelectric motor. The first Z-axis adjustment mechanism 3 is used to displace the objective lens 24 of the irradiation unit 2 relative to the housing 5, and further relative to the stage 9 and the object O to be processed in the Z-axis direction.

Furthermore, in this embodiment, a single piezoelectric motor XYZ stage is used to realize the two functions of the first XY stage 3 and the first Z axis adjustment mechanism 3. The piezoelectric XYZ stage 3 is a stage that can move the objective lens 24 and the rotator 241 in three-dimensional directions, namely, the X-axis direction, the Y-axis direction, and the Z-axis direction.

The components other than the objective lens 24 of the irradiation unit 2 or the displacement meter 4 do not necessarily need to be mounted on the piezoelectric XYZ stage 3. The intention is to reduce the load of the piezoelectric XYZ stage 3 and to improve the accuracy and responsiveness of the position control of the objective lens 24 by the piezoelectric XYZ stage 3 as much as possible. However, it does not exclude that at least a part of the components other than the objective lens 24 of the irradiation unit 2 is mounted on the piezoelectric XYZ stage 3 and moved together with the objective lens 24, and it does not exclude that the displacement meter 4 is mounted on the piezoelectric XYZ stage 3 and moved together with the objective lens 24.

The piezoelectric XYZ stage 3 serving as the first XY stage and the first Z-axis adjustment mechanism is provided with an optical linear encoder, and the position coordinates of the stage in the X-axis direction, the Y-axis direction, and the Z-axis direction are detected by the linear encoder.

The width of the object O assumed in this embodiment along the X-axis direction and the Y-axis direction is more than 1m. In order to be able to perform the process of irradiating the laser light L to the substantially entire area of such a large object O, the stroke (i.e., the movable range in the two-dimensional direction) of the second XY stage 7 is more than 1m. That is, the movable range of the Y-axis linear motor carriage 72 in the Y-axis direction is more than 1m, and the movable range of the X-axis linear motor carriage 74 in the X-axis direction is also more than 1m.

On the other hand, the stroke of the first XY stage 3 (i.e., the movable range in the X-axis direction and the Y-axis direction) is much smaller than that of the second XY stage 7, and the movable range in the X-axis direction and the Y-axis direction of the stage supporting the objective lens 24 is less than 100 μm, and is as close as possible to 40 μm to 50 μm. Instead, the minimum displacement of the first XY stage 3 is much smaller than that of the second XY stage 7. The first XY stage 3 can adjust the position of the objective lens 24 in the X-axis direction and the Y-axis direction more finely and precisely than the second XY stage 7. Furthermore, the resolution of position coordinate detection by the optical linear encoder attached to the first XY stage 3 is higher than the resolution of position coordinate detection by the linear encoder attached to the second XY stage 7.

Furthermore, the stroke of the first Z-axis adjustment mechanism 3 (i.e., the movable range in the Z-axis direction) is much smaller than that of the second Z-axis adjustment mechanism 6, and the movable range in the Z-axis direction of the mounting table supporting the objective lens 24 is about 10 μm to 30 μm. Instead, the minimum displacement of the first Z-axis adjustment mechanism 3 is much smaller than that of the second Z-axis adjustment mechanism 6. The first Z-axis adjustment mechanism 3 can adjust the position of the objective lens 24 in the Z-axis direction more finely and precisely than the second Z-axis adjustment mechanism 6. In addition, the resolution of the position coordinates detected by the optical linear encoder attached to the first Z-axis adjustment mechanism 3 is higher than the resolution of the position coordinates detected by the linear encoder attached to the second Z-axis adjustment mechanism 6.

The control controller 8 that controls the laser processing device 1 is mainly composed of, for example, a general-purpose personal computer or workstation. As shown in FIG3 , the control controller 8 has hardware resources such as a CPU (Central Processing Unit) 81, a main memory 82, an auxiliary memory device 83, a video codec 84, a display 85, a communication interface 86, and an operation input device 87, and these coordinate operations.

The auxiliary memory device 83 is a flash memory, a hard disk drive, an optical disk drive, etc. The video codec 84 is based on a GPU (Graphics Processing Unit), a video memory, etc. The GPU generates a screen to be displayed based on the drawing instructions received from the CPU 81 and sends the screen signal to the display 85. The video memory temporarily stores the screen or image data in advance. The video codec 84 can also be installed as software instead of hardware. The communication interface 86 refers to a device for the control controller 8 to communicate information with external devices. The operation input device 87 refers to a keyboard operated by the operator with fingers, a button for pressing, a joystick, a mouse or a pointing device of a touch panel (sometimes superimposed with the display 85), and others.

In the control controller 8, the program to be executed by the CPU 81 is stored in the auxiliary memory device 83. When the program is executed, it is read from the auxiliary memory device 83 to the main memory 82 and decoded by the CPU 81. The control controller 8 activates the above-mentioned hardware resources according to the program and implements the control of the laser processing device 1.

Fig. 4 shows an example of the processing sequence performed by the control controller 8 during laser processing by the laser processing device 1. First, the control controller 8 provides a control signal to the second XY stage 7, and drives the second XY stage 7 to move the housing 5 including the irradiation unit 2 in the X-axis direction and/or the Y-axis direction, so that the irradiation position of the laser light L irradiated on the object O through the optical axis of the objective lens 24 (i.e., the objective lens 24) is consistent with the target position on the object O or is located near it, as a preparation for irradiating the laser light L from the irradiation unit 2 of the laser processing device 1 toward the target position on the object O (step S1). The control controller 8 stores the XYZ coordinates of the target position on the object O in advance in the main memory 82 or the auxiliary memory device 83. The XYZ coordinates of the target position are obtained by, for example, analyzing an image obtained by photographing a liquid crystal display panel as the object O, and detecting defective parts of the object O.

Next, the control controller 8 provides a control signal to the first XY stage 3, and drives the first XY stage 3 to finely adjust the position of the objective lens 24 of the irradiation unit 2 in the X-axis direction and/or the Y-axis direction, so that the irradiation position of the laser light L irradiated on the object O through the objective lens 24 is precisely aligned with the target position on the object O (step S2). At this time, the position intersecting with the optical axis of the objective lens 24 in the object O and its surrounding area are photographed through the camera sensor 25 of the irradiation unit 2, and the obtained image is analyzed to detect the defective part of the object O as the target position, and the displacement caused by the first XY stage 3 can be finely corrected in order to make the optical axis accurately align with the defective part. However, it is preferred that the image of the object O to be processed be taken by the camera sensor 25 after the focus of the objective lens 24 is aligned with the object O to be processed.

Almost simultaneously with the above step S2, the control controller 8 provides a control signal to the Z-axis adjustment mechanism 3, 6, and drives the Z-axis adjustment mechanism 3, 6 to finely adjust the position of the housing 5 of the irradiation unit 2 and/or the objective lens 24 in the Z-axis direction, so that the focus of the laser light L irradiated on the object O through the objective lens 24 and the focus of the laser light L irradiated on the object O through the objective lens 24 are precisely aligned with the target position on the object O (step S3). In the step S3, the function of the displacement meter 4 is not used. In step S3, for example, the camera sensor 25 of the irradiation unit 2 is used to repeatedly photograph the position where the optical axis of the objective lens 24 in the processed object O intersects and its surrounding area, and the obtained images are analyzed to successively calculate their contrast (difference in light and dark), and the housing 5 and/or the objective lens 24 are moved up and down until the contrast of the photographed image reaches a maximum or nearly maximum height position.

The reason why the displacement meter 4 is not used in step S3 is as follows: As shown in FIG. 2 , the irradiation position of the laser light L irradiated through the objective lens 24 for laser treatment of the object O and the irradiation position of the laser light R irradiated for measuring the distance from the displacement meter 4 to the object O are offset from each other. The objective lens 24 has a large magnification and the size of the objective lens 24 itself is also large. In order to avoid interference with the objective lens 24, the displacement meter 4 has to be arranged away from the objective lens 24, and it is definitely difficult to make the optical axis of the displacement meter 4 consistent with the optical axis of the objective lens 24. A large object O may be bent or deformed in whole or in part. As long as the degree of bending deformation is not always constant, the interval distance measured by the displacement meter 4 cannot be immediately regarded as the distance from the objective lens 24 to the target position on the object O to be processed. In other words, the position where the displacement meter 4 measures the interval distance is different from the position hit by the laser light L emitted from the objective lens 24, and the heights of the two positions along the Z-axis direction may be different due to the bending of the irradiated object, and the difference in height between the two positions is not significant in advance. Therefore, in step S3, the displacement meter 4 is not used, but the focus of the laser light L is aligned with the irradiation position on the object O to be processed by contrast AF (AutoFocus) method or the like.

After the above steps S1 to S3, the objective lens 24 of the irradiation unit 2 reaches the basic position required for irradiating the target position on the object O with the laser light L. Thereafter, the control controller 8 starts feedback control to maintain the objective lens 24 at the basic position (steps S4 and S5). The reason for performing position feedback control is to prevent the laser light L from being irradiated on the object O in a state where the optical axis or focus of the laser light L deviates from the target position on the object O due to disturbance. Typical disturbances refer to vibrations transmitted from the floor of the factory or the like where the laser processing device 1 is installed to the stage 9, the object O, the XY stage 7, the Z-axis adjustment mechanism 6, and the irradiation unit 2. Vibrations with higher frequencies (over 5 Hz) above a certain level are blocked or sufficiently attenuated by the anti-vibration member 91 interposed between the floor and the gantry 9. However, vibrations with lower frequencies (less than 5 Hz, about 2 Hz to 3 Hz) may not be blocked by the anti-vibration member 91 and may be transmitted from the floor to the gantry 9, the object O, the XY stage 7, the Z-axis adjustment mechanism 6 and the irradiation unit 2.

In the position feedback control step S4 in the X-axis direction and the Y-axis direction, the control controller 8 repeatedly photographs the position intersecting with the optical axis of the object lens 24 in the processed object O and its surrounding area through the camera sensor 25 of the irradiation unit 2 after positioning the irradiation unit 2 at the basic position, and analyzes the obtained images to successively find out how much the current position of the irradiation unit 2 deviates from the basic position, that is, from the position when the irradiation position of the laser light L is aligned with the target position, in the X-axis direction and the Y-axis direction, or its deviation. Then, a control signal is provided to the first XY stage 3, and the first XY stage 3 is driven in a direction to reduce the deviation, so as to correct the position of the object lens 24 toward the basic position. In this way, the optical axis of the objective lens 24, in other words, the irradiation position of the laser light L, can be continuously maintained at the target position on the object O to be processed or near it.

In the Z-axis position feedback control step S5, the control controller 8 measures the distance to the object O through the displacement meter 4 when the irradiation unit 2 is positioned at the basic position, and sets the distance as the target distance of the feedback control. In addition, the displacement meter 4 repeatedly measures the distance to the object O, and the deviation between the measured current distance and the target distance is successively calculated. The deviation indicates how much the current position of the irradiation unit 2 deviates from the basic position, that is, from the position when the focus of the laser light L is aligned with the target position, in the Z-axis direction. Then, a control signal is provided to the first Z-axis adjustment mechanism 3, and the first Z-axis adjustment mechanism 3 is driven in the direction of reducing the deviation to correct the position of the objective lens 24 toward the basic position. In this way, the focus of the laser light L can be continuously maintained at the target position or its vicinity on the object O to be processed.

It is possible to quickly correct the deviation caused by low-frequency vibration transmitted from the floor to the gantry 9, the object O, the XY stage 7, the Z-axis adjustment mechanism 6 and the irradiation unit 2 based on position feedback control. The piezoelectric motor stage 3 as the first XY stage and the first Z-axis adjustment mechanism has a response speed sufficient to correct the deviation caused by low-frequency vibration.

In addition, the movable range of the piezoelectric motor stage 3 supporting the objective lens 24 is as small as less than 100μm. Moreover, the laser light L supplied from the laser oscillator 26 and incident on the objective lens 24 refers to collimated parallel light. Therefore, even if the elements other than the objective lens 24 of the irradiation unit 2 are not mounted on the piezoelectric motor stage 3, when the objective lens 24 is displaced in the X-axis direction or the Y-axis direction through the piezoelectric motor stage 3, the position photographed by the camera sensor 25 on the processed object O and the position of the irradiated laser light L will only be displaced by the same amount. There is no problem even if the objective lens 24 is displaced in the Z-axis direction through the piezoelectric motor stage 3.

Then, the controller 8 performs position feedback control while irradiating the laser light L to the target position on the object O to be processed (step S6).

In the present embodiment, a laser processing device 1 is provided for performing processing by irradiating a laser light L toward a target position on an object O to be processed, and comprises: an irradiation unit 2 having an objective lens 24 for focusing the laser light L toward a target position on the object O to be processed; and a first XY stage 3, which can move at least the objective lens 24 of the irradiation unit 2 relative to the object O in a two-dimensional direction that is orthogonal or substantially orthogonal to the laser light axis; and a second XY stage 7, which can move the irradiation unit 2 and the first XY stage 3 relative to the object O in a two-dimensional direction that is orthogonal or substantially orthogonal to the laser light axis, and the movable range in the two-dimensional direction is larger than that of the first XY stage 3.

In the present embodiment, the second XY stage 7 is responsible for the task of moving the irradiation unit 2 in a large size corresponding to the large-sized object O, and the first XY stage 3 is responsible for the task of finely and precisely adjusting the position of the irradiation unit 2, especially the objective lens 24. More specifically, the laser light L is irradiated to the object O while the following control is performed: after the irradiation unit 2 is positioned by the second XY stage 7 in such a manner that the irradiation position of the laser light L irradiated to the object O through the objective lens 24 is aligned to the target position on the object O or its vicinity, the objective lens 24 of the irradiation unit 2 is held by the first XY stage 3 so that the irradiation position of the laser light L is aligned to the target position. According to this embodiment, the irradiation position of the laser light L irradiated from the irradiation unit 2 of the laser processing device 1 through the objective lens 24 to the processing object O can be accurately aligned with the target position on the processing object O.

Since the irradiation unit 2 has a camera sensor 25 that photographs a part of the object O to be processed through the objective lens 24, and based on the image photographed through the camera sensor 25, detects the deviation between the current position of the objective lens 24 and the position of the objective lens 24 when the irradiation position of the laser light L is aligned with the target position, and in order to reduce the deviation, the position of the objective lens 24 of the irradiation unit 2 is adjusted by the first XY stage 3, thereby improving the accuracy of the position feedback control, and can suppress the deviation of the target position from the irradiation position of the laser light L to a minimum relative to the disturbance.

Between the stand 9 supporting the object O, the irradiation unit 2, the XY stage 3, 7, the Z-axis adjustment mechanism 3, 6 and the displacement meter 4, and the floor surface, there is interposed an anti-vibration component 91 for suppressing vibrations with a frequency higher than a predetermined value from being transmitted from the floor surface to the stand 9. This can appropriately block or attenuate high-frequency vibrations that have a greater impact and are difficult to correct and cause disturbances.

Furthermore, the present invention is a laser processing device 1 for performing processing by irradiating a laser beam L toward a target position on an object O to be processed, and comprises: an irradiation unit 2, which has an objective lens 24 for focusing the laser beam L toward a target position on the object O to be processed; and a Z-axis adjustment mechanism 3, 6, which can move at least the objective lens 24 of the irradiation unit 2 relative to the object O to be processed in a direction parallel or substantially parallel to the laser beam axis; and a displacement meter 4, which measures the distance from the irradiation unit 2 to the object O to be processed; while performing feedback control, the laser beam L is directed to the target position on the object O to be processed; The light L is irradiated onto the processed object O. The feedback control is performed by positioning the irradiation unit 2 in such a manner that the focus of the laser light L irradiated onto the processed object O through the objective lens 24 is aligned with the target position on the processed object O without relying on the displacement meter 4. Then, the distance from the irradiation unit 2 to the processed object O is measured by the displacement meter 4, and after the distance is set as the target distance, the position of the objective lens 24 of the irradiation unit 2 is adjusted by the Z-axis adjustment mechanism 3 in order to reduce the deviation between the distance currently measured by the displacement meter 4 and the target distance.

More specifically, the irradiation unit 2 has a camera sensor 25 for photographing a part of the object O through the objective lens 24, and based on the image photographed through the camera sensor 25, after the irradiation unit 2 is positioned in such a manner that the focus of the laser light L irradiated on the object O through the objective lens 24 is aligned with the target position on the object O, the distance from the irradiation unit 2 to the object O is measured by the displacement meter 4, and the distance is set as the target distance. According to this embodiment, in the laser processing device 1 for processing a large object O, the focus of the laser light L irradiated on the object O from the irradiation unit 2 can be accurately aligned with the target position on the object O.

The laser processing device 1 of this embodiment is equipped with XY stages 3, 7 that can move the irradiation unit 2 relative to the object O in a two-dimensional direction that is orthogonal or approximately orthogonal to the laser light axis, and through the function of the XY stages 3, 7, the irradiation position of the laser light L emitted from the objective lens 24 can be accurately aligned with the target position on the object O. The laser processing device 1 of the present embodiment is configured such that after the irradiation position of the laser light L irradiated on the object O through the objective lens 24 is aligned with the target position on the object O by the XY stage 3, 7, and after the irradiation unit 2 is positioned such that the focus of the laser light L is aligned with the target position on the object O by the Z-axis adjustment mechanism 3, 6, the distance from the irradiation unit 2 to the object O is measured by the displacement meter 4, and the distance is set to the target distance.

The laser processing device 1 of this embodiment can be preferably used as a laser repair device for irradiating laser light L to defective parts produced by liquid crystal display modules, plasma display modules, organic EL display modules, inorganic EL display modules, micro-luminescent diode display modules, transparent conductive film substrates or color filters.

Furthermore, the present invention is not limited to the above-described embodiments. For example, the use of the laser processing device 1 of the present invention is not limited to a laser repair device.

In addition, the specific structure of each part or the processing order can be changed in various ways without departing from the scope of the present invention. [Industrial Applicability]

The present invention is applicable to a laser processing device that irradiates a processing object with laser light and performs a desired processing.

1: Laser processing device 2: Irradiation unit 3: First XY stage and first Z axis adjustment mechanism (piezoelectric XYZ stage) 4: Displacement meter 5: Housing 6: Second Z axis adjustment mechanism (screw feed mechanism) 7: Second XY stage 9: Stand 20: Variable slit 21: Falling illumination light source (laser oscillator) 22: Beam splitter 23: Two-way beam splitter 24: Objective lens 25: Camera sensor 26: Oscillator 27: Attenuator 28: Polarizing plate 29: Beam expander 71: Y-axis track 72: Y-axis linear motor trolley 73: X-axis track 74: X-axis linear motor trolley 81: CPU 82: Main memory 83: Auxiliary memory device 84: Video encoder/decoder 85: Display 86: Communication interface 87: Operation input device 91: Anti-vibration component 241: Electric rotator (rotator) 251: Imaging lens L, R: Laser light O: Object to be processed

[FIG. 1] is a schematic diagram showing the overall outline of a laser processing device of one embodiment of the present invention. [FIG. 2] is a schematic diagram showing the optical system, the first XY stage and the displacement meter of the irradiation unit of the laser processing device of the same embodiment. [FIG. 3] is a schematic diagram showing the structure of the control controller of the laser processing device of the embodiment. [FIG. 4] is a flow chart showing an example of the sequence of processing of the control controller of the laser processing device of the embodiment according to a program.

Claims (7)

A laser processing device is a laser processing device that performs processing by irradiating laser light toward a target position on a processed object, and is characterized in that it comprises: an irradiation unit having an objective lens for focusing the laser light toward the target position on the processed object; and a first XY stage, which can move at least the objective lens of the irradiation unit relative to the processed object in a two-dimensional direction that is orthogonal or substantially orthogonal to the laser light axis; and a second XY stage, which can move the irradiation unit and the first XY stage relative to the processed object in a two-dimensional direction that is orthogonal or substantially orthogonal to the laser light axis, and the movable range in the two-dimensional direction is larger than that of the first XY stage; wherein the laser light is irradiated to the processed object while the following control is performed: The control is to position the irradiation position of the laser light irradiated on the object to be processed by the irradiation unit through the object lens at the target position or its vicinity on the object to be processed by the second XY stage, and then maintain the object lens of the irradiation unit by the first XY stage so that the irradiation position of the laser light is aligned with the target position; wherein the irradiation unit has a camera sensor for photographing a part of the object to be processed through the object lens, and performs the following feedback control: based on the image photographed by the camera sensor, the deviation between the current position of the object lens and the position of the object lens when the irradiation position of the laser light is aligned with the target position is detected, and in order to reduce the deviation, the position of the object lens of the irradiation unit is adjusted by the first XY stage. The laser processing device of claim 1, wherein the device also has: a Z-axis adjustment mechanism, which can move at least the objective lens of the aforementioned irradiation unit relative to the object to be processed in a direction parallel or approximately parallel to the laser optical axis. The laser processing device of claim 1, wherein the device also has: a vibration-proof member, which is interposed between a platform and a floor surface for supporting the object to be processed, the irradiation unit, the first XY stage and the second XY stage, and is used to suppress vibrations with a frequency higher than a predetermined value from being transmitted from the floor surface to the platform. A laser processing device is a laser processing device that performs processing by irradiating a laser beam toward a target position on a processed object, and is characterized in that it comprises: an irradiation unit having an objective lens for focusing the laser beam toward the target position on the processed object; and a Z-axis adjustment mechanism that can move at least the objective lens of the irradiation unit in a direction parallel or substantially parallel to the laser beam axis relative to the processed object; A displacement meter that measures the distance from the irradiation unit to the object to be processed; an XY stage that can move at least the objective lens of the irradiation unit relative to the object to be processed in a two-dimensional direction that is orthogonal or substantially orthogonal to the laser light axis; and a control controller; wherein the target position of the object to be processed that is hit by the laser light emitted through the objective lens is offset inconsistently with the position on the object to be processed measured by the displacement meter; wherein the control controller irradiates the object to be processed with the laser light while executing feedback control, the feedback control being performed after the irradiation unit is positioned by the XY stage in such a manner that the focus of the laser light irradiated on the object to be processed through the objective lens is aligned with the target position on the object to be processed without relying on the displacement meter, and after the Z-axis adjustment is performed, the laser light is irradiated on the object to be processed. After the mechanism positions the irradiation unit by aligning the focus of the laser light at the target position on the object to be processed, the displacement meter is used to measure the distance from the irradiation unit to the object to be processed, and after the distance is set to the target distance, the position of the objective lens of the irradiation unit is adjusted by the Z-axis adjustment mechanism in order to reduce the deviation between the distance currently measured by the displacement meter and the target distance. As in claim 4, the laser processing device, wherein the irradiation unit has a camera sensor for photographing a part of the processed object through the objective lens, and based on the image photographed by the camera sensor, the irradiation unit is positioned in a manner that the focus of the laser light irradiated on the processed object through the objective lens is aligned with the target position on the processed object, and the distance from the irradiation unit to the processed object is measured by the displacement meter, and the distance is set to the target distance. The laser processing device of claim 4, wherein the device also has: a vibration-proof member, which is interposed between the stand and the floor surface for supporting the object to be processed, the irradiation unit, the Z-axis adjustment mechanism and the displacement meter, and is used to suppress vibrations with a frequency higher than a predetermined value from being transmitted from the floor surface to the stand. The laser processing device of claim 1, 2, 3, 4, 5 or 6 is a laser repair device for irradiating laser light to defective parts of a liquid crystal display module, a plasma display module, an organic EL display module, an inorganic EL display module, a micro-LED display module, a transparent conductive film substrate or a color filter.

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