TWI617384B - Focusing point detecting device - Google Patents

Abstract

The invention discloses a light spot detection device. The device includes: a laser light source configured to emit a processing beam; a first beam splitter provided between the light source and a condensing optical system for condensing the processing beam; and configured to reflect a self-processing object At least a part of the reflected reflected beam; a first lens portion provided to focus the reflected beam reflected from the first beam splitter; and a first light sensor provided to the reflected beam from the lens portion The focusing direction is set to measure the energy density of the reflected beam focused by the first lens unit.

Description

Condensing point detection device

The invention discloses a light spot detection device and a technology for adjusting the position where a laser beam is focused on a processed object.

Generally, a laser processing process is a process in which a laser beam is scanned toward the surface of a processing object, and the shape, physical properties, and the like of the surface of the processing object are processed. There may be many examples of the object to be processed, and the shape may be a two-dimensional planar shape. Examples of laser processing include laser marking, laser cutting, and laser grooving processes.

In order to improve the accuracy of laser processing, it is important to well adjust the position of the light-condensing point of the laser beam emitted from the light source. In addition, in order to adjust the position of the focusing point of the laser beam, it is necessary to determine to which position the focused point of the laser beam is formed on the workpiece.

In the conventional laser processing apparatus, in order to indirectly know the condensing point of the laser beam, a measurement unit for measuring the surface height of the object to be processed is provided in parallel with the condenser lens that condenses the laser light. This type of laser processing device scans the surface of a processing object while measuring the surface height of the processing object by a measuring unit, and uses a condenser lens and the processing object based on the surface height measured in this way. The condenser lens is driven in such a way that the distance of the surface becomes fixed. As a result, even the object to be processed The uneven surface of the laser beam can also be used to perform laser processing by always concentrating the spot of the laser light on the surface of the object to be processed.

However, in the conventional laser processing apparatus as described above, the condenser lens and the measurement unit are provided at a fixed distance from each other, and therefore the actual surface height and Since an error occurs between the surface heights measured by the measurement unit, the position of the light-condensing point of the laser light is deviated from a desired position.

As another example, there is also a method of tracking the path of the reflected beam reflected by the processed beam on the processed beam, and inferring the position of the focal point of the processed beam. However, in this case, due to changes in the thickness of the workpiece and errors in the drive optical system such as a scanner or lens located on the laser beam path, the position of the focusing point cannot be known, or even if the position of the focusing point is known, the reliability Also reduced.

According to an exemplary embodiment, a condensing point detection device that detects a condensing point position of a laser processing beam is provided.

In one aspect, a light spot detection device is provided that detects a position of a light spot of a laser processing beam. The light spot detection device includes: a first beam splitter, a laser light source configured to emit the processing beam, and Reflection between the light collecting optical system for condensing the processing beam from the processing object At least a part of the reflected beam; a first lens unit for focusing the reflected beam reflected from the first beam splitter; and a first light sensor provided from the first lens unit for focusing the reflected beam. In the direction, the energy density of the reflected beam focused by the first lens unit is measured.

The position of the condensing optical system can be determined based on the energy density of the reflected beam measured by the first light sensor.

The focusing point detection device may further include a second beam splitter, and the second beam splitter divides the reflected beam reflected from the first beam splitter into a first reflected beam and a second reflected beam.

The first reflected beam is incident on the first lens portion, and the condensing point detection device may include a second lens portion for the second reflected beam to be incident; and a second light sensor provided from the second lens portion. An energy density of the second reflected beam focused by the second lens section is measured in a direction in which the second reflected beam is focused.

The concentration of the light collecting optical system can be determined based on the energy density of the first reflected beam measured by the first light sensor and the energy density of the second reflected beam measured by the second light sensor. position.

The position of the condensing optical system may be determined according to a difference between the energy density of the first reflected beam and the energy density of the second reflected beam.

The first light sensor can have a longer focal length than the first lens portion. The second light sensor is disposed away from the first lens portion, and the second light sensor is disposed closer to the second lens portion than a focal length of the second lens portion.

The first light sensor may be disposed closer to the first lens portion than the focal length of the first lens portion, and the second light sensor may be farther from the second lens portion than the second lens portion. Way setting.

The condensing point detection device may further include: a third beam splitter that changes a traveling direction of the second reflected beam obtained by the second beam splitter; and a measurement light source that emits measurement light to the third beam splitter. beam.

The first beam splitter may reflect at least a part of a reflected beam reflected by the measurement beam on the object to be processed.

The wavelength of the measurement beam emitted from the measurement light source is different from the wavelength of the light emitted from the laser light source. The first beam splitter can transmit light emitted from the laser light source and transmit the light from the measurement light source. The emitted measurement beam is reflected.

The condensing point detection device may further include a second beam splitter, and the second beam splitter divides the reflected beam focused by the first lens portion into a first reflected beam and a second reflected beam.

The first light sensor is provided to a travel path of the first reflected beam, and can measure an energy density of the first reflected beam.

The above-mentioned light spot detection device may further include a second light sensor. A light sensor is provided to a travel path of the second reflected beam, and measures an energy density of the second reflected beam.

The position of the condensing optical system can be determined based on the energy density of the first reflected beam measured by the first light sensor and the energy density of the second reflected beam measured by the second light sensor. .

According to an embodiment, there is provided a condensing point detection device that can accurately and stably detect the position of a condensing point of a processed beam even if a condensing optical system changes and a thickness of a processed object changes.

10‧‧‧ light source

20‧‧‧ Condensing optical system

21, 23‧‧‧ scanner

22‧‧‧ concave lens

24, 26‧‧‧ convex lens

25‧‧‧ lens

30‧‧‧Processed

110‧‧‧first beam splitter

120‧‧‧Second Beamsplitter

122‧‧‧Mirror

123‧‧‧third beam splitter

132‧‧‧First lens section

134‧‧‧Second lens section

142‧‧‧The first light sensor

144‧‧‧Second light sensor

150‧‧‧light source for measurement

d0, f ', f ", f1', f2 ', 11, 12, t1, t1', t1", t2, t2 ', t2 "‧‧‧ distance

d1‧‧‧distance / height

d2‧‧‧distance / depth

f, f1, f2‧‧‧ focal length

f1 "‧‧‧distance

f2 "‧‧‧distance

L1‧‧‧Processing beam

L1'‧‧‧ transmitted beam

L2‧‧‧Reflected Beam

L3‧‧‧Beam for measurement

L21‧‧‧First reflected beam

L22‧‧‧Second reflected beam

Lu‧‧‧Reflected light

P‧‧‧concentrating point

Sd‧‧‧ lower surface

Su‧‧‧ Top surface

FIG. 1 is a diagram schematically showing a light spot detection device according to an exemplary embodiment.

FIG. 2 is a diagram illustrating an example in which a distance between a condensing optical system and a processed object shown in FIG. 1 changes.

FIG. 3 is a diagram showing another example in which the distance between the condensing optical system and the processed object shown in FIG. 1 changes.

FIG. 4 is a diagram showing a modified example of the embodiment shown in FIG. 1.

FIG. 5 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

FIG. 6 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

FIG. 7 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

FIG. 8 is a diagram showing an example in which the distance between the condensing optical system and the processed object shown in FIG. 7 changes.

FIG. 9 is a diagram showing another example in which the distance between the condensing optical system and the processed object shown in FIG. 7 changes.

FIG. 10 is a graph showing changes in the energy density of the first reflected beam and the energy density of the second reflected beam measured by the first light sensor.

11 and 12 are diagrams showing a modification example of the condensing optical system shown in FIG. 7.

FIG. 13 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

FIG. 14 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

FIG. 15 is a diagram showing an example in which the laser processing apparatus of the exemplary embodiment forms a light-condensing point of the processing beam L1 inside the processed object.

FIG. 16 is an enlarged view showing a condensing point of a processing beam formed inside the processed product shown in FIG. 15.

In the following drawings, the same reference symbols represent the same constituent elements, and in the drawings, the dimensions of each constituent element may be exaggerated for clarity and convenience of explanation. On the other hand, the embodiments described below are merely examples, The embodiment realizes various modifications.

The first and second terms can be used to describe various constituent elements, but the constituent elements should not be limited by the terms. The term is used only for the purpose of distinguishing one constituent element from the other constituent elements.

As long as other meanings are not clearly indicated in the text, expressions in the singular include expressions in the plural. In addition, when it is described that a certain part “includes” a certain constituent element, as long as there is no particularly contrary description, it means that other constituent elements may be further included instead of excluding other constituent elements.

In addition, terms such as "... section" and "module" described in the specification refer to a unit that processes at least one function or operation.

FIG. 1 is a diagram schematically showing a light spot detection device according to an exemplary embodiment.

Referring to FIG. 1, the processing beam L1 emitted from the light source 10 may be irradiated to the processed object 30 via the condensing optical system 20. The condensing optical system 20 can condense the processing beam L1. In FIG. 1, it is exemplarily shown that the condensing optical system 20 includes one lens, but it is not limited thereto. The condensing optical system 20 only needs to change the light path of the processing beam L1 to condense the processing beam L1, and may include a plurality of optical elements. In addition, FIG. 1 shows an example in which the light-condensing point of the processing beam L1 is formed on the surface of the workpiece 30, but the position of the light-condensing point of the processing beam L1 can be changed according to the laser processing characteristics.

The condensing point detection device of the embodiment can detect the distance between the condensing point of the processing beam L1 passing through the concentrating optical system 20 and the surface of the processed object 30. If the focusing point detection device provides the user with the distance from the focusing point of the processing beam L1 to the surface of the processed object 30 For related information, the user can change the setting of the condensing optical system 20 based on the position information of the condensing point. The setting change of the condensing optical system 20 can be realized manually, or can be automatically realized by the condensing point detection device of the embodiment. Although not shown, when the position of the condensing optical system 20 is automatically adjusted, the condensing point detection device may include a driving device that adjusts the position of the condensing optical system.

In order to detect the spot position of the processing beam L1, the spot detection device measures the reflected beam L2 reflected from the processed object 30. The condensing point detection device may include a first beam splitter 110 that reflects at least a part of the above-mentioned reflected beam L2. The first beam splitter 110 may reflect all or a portion of the reflected beam L2 reflected from the processed object 30. In addition, the processing beam L1 incident on the first beam splitter 110 may be transmitted through the first beam splitter 110 in whole, or may be incident on the processed object 30 for part transmission and reflected on the other part. If the wavelength of the processed beam L1 emitted from the light source 10 and the reflected beam L2 reflected from the processed object are different, the first beam splitter 110 may reflect the beam only for the wavelength of the reflected beam L2 and the wavelength of the processed beam L1 The light beam is transmitted. In this case, the surface of the first beam splitter 110 can be coated and processed so as to reflect a light beam of a specific wavelength and transmit light beams of other wavelengths.

The condensing point detection device may include a first lens portion 132 that focuses the reflected beam L2 whose path is changed by the first beam splitter 110. The first lens portion 132 may be an optical element that can focus the reflected beam L2. In FIG. 1, the first lens portion 132 is shown as a semi-convex lens, but the embodiment is not limited thereto. The first lens portion 132 is only required to be able to focus the reflected beam L2, and the shape of the lens included in the first lens portion 132 may be variously changed. In addition, in FIG. 1, The first lens portion 132 includes an example of a lens, but the embodiment is not limited thereto. For example, the first lens portion 132 may include a plurality of lenses. Furthermore, as described below, the lens included in the first lens portion 132 is not limited to a convex lens, and may include a concave lens. The first lens portion 132 may include at least one condenser lens, so as to focus a light beam passing through the first lens portion 132.

The condensing point detection device may include a first light sensor 142 that measures an energy density of the reflected beam L2 focused by the first lens portion 132. The first light sensor 142 may be disposed from the first lens portion 132 in a direction in which the reflected beam L2 is focused. In FIG. 1, a case is exemplarily shown in which the first light sensor 142 is further away from the first lens portion 132 by a distance d0 than the focal length f of the first lens portion 132. However, the position of the first light sensor 142 shown in FIG. 1 is merely an example, and is not limited thereto. For example, the first light sensor 142 may be further away from the first lens portion 132 than the focal length f of the first lens portion 132.

The first light sensor 142 can measure the energy density of the reflected beam L2 passing through the first lens portion 132. Here, the energy density of the reflected beam L2 refers to energy per unit area transmitted from the incident surface of the reflected beam L2. The energy density of the reflected beam L2 is relatively large in a region where the condensing area of the reflected beam L2 is narrow, and the energy density of the reflected beam L2 is relatively small in a region where the incident area of the reflected beam L2 is large. That is, if the position of the first light sensor 142 is close to the light-condensing point of the reflected beam L2 passing through the first lens section 132, the energy density of the reflected beam L2 measured by the first light sensor 142 is large. Conversely, if the position of the first light sensor 142 is far from the light-condensing point of the reflected beam L2 passing through the first lens portion 132, the reflection measured by the first light sensor 142 The energy density of the beam L2 will be smaller.

FIG. 2 is a diagram showing an example in which the distance between the condensing optical system 20 and the workpiece 30 shown in FIG. 1 changes.

Referring to FIG. 2, the distance between the processed object 30 and the condensing optical system 20 becomes larger than the distance shown in FIG. 1. Therefore, the light-condensing point of the processing beam L1 by the light-concentrating optical system 20 can be formed on the surface of the processed object 30. The angle at which the reflected beam L2 reflected from the surface of the processed object 30 is incident on the light-concentrating optical system 20 due to the light-condensing point of the processed beam L1 being formed on the surface of the processed object 30. In addition, as the angle of the reflected beam L2 incident on the condenser optical system 20 changes, the angle of the reflected beam L2 incident on the first beam splitter 110 also changes. As shown in FIG. 2, if the condensing point of the processing beam L1 is located on the surface of the processed object 30, unlike the case of FIG. 1, the beam size of the reflected beam L2 reflected from the first beam splitter 110 gradually becomes smaller. In addition, the distance f ′ between the condensing point of the reflected beam L2 passing through the first lens portion 132 and the first lens portion 132 becomes smaller than the focal length f of the first lens portion 132.

As the distance f ′ between the light-condensing point of the reflected beam L2 and the first lens portion 132 becomes smaller, the distance d1 between the first light sensor 142 and the light-condensing point of the reflected beam L2 becomes larger than that shown in FIG. 1. Shown distance d0. Therefore, the energy density of the reflected beam L2 measured by the first light sensor 142 is reduced. That is, if the first light sensor 142 is arranged as shown in FIG. 1 and the position of the processed object 30 is further distant from the condensing optical system 20 as shown in FIG. 2, the first light sensor is used. The energy density of the reflected beam L2 measured at 142 decreases.

FIG. 3 is a view showing one of the condensing optical system 20 and the processed object 30 shown in FIG. 1. Another example of the change in the distance between the two.

Referring to FIG. 3, the distance between the processed object 30 and the condensing optical system 20 becomes smaller than the distance shown in FIG. 1. Therefore, the processing beam L1 passing through the light-concentrating optical system 20 is reflected on the surface of the processed object 30 before the light-condensing point is formed. Therefore, the angle at which the reflected beam L2 reflected on the surface of the workpiece 30 enters the condenser optical system 20 changes. In addition, as the angle of the reflected beam L2 incident on the condenser optical system 20 changes, the angle of the reflected beam L2 incident on the first beam splitter 110 also changes. As shown in FIG. 3, if the processing beam L1 is reflected on the surface of the processed object 30 before the light collecting point of the processing beam L1 is formed, the beam size of the reflected beam L2 reflected by the first beam splitter 110 will gradually increase. In addition, the distance f "between the light-condensing point of the reflected beam L2 passing through the first lens portion 132 and the first lens portion 132 becomes larger than the focal length f of the first lens portion 132.

As the distance f "between the focusing point of the reflected beam L2 and the first lens portion 132 becomes larger, the distance d2 between the first light sensor 142 and the focusing point of the reflected beam L2 becomes smaller than that shown in FIG. 1. Therefore, the energy density of the reflected beam L2 measured by the first light sensor 142 increases. That is, if the first light sensor 142 is disposed as shown in FIG. 1, the processed object 30 As the distance from the condenser optical system 20 increases, the energy density of the reflected beam L2 measured by the first light sensor 142 increases.

As described with reference to FIGS. 1 to 3, the energy density of the reflected beam L2 measured by the first light sensor 142 changes due to a change in the distance between the condensing optical system 20 and the workpiece 30. That is, the first light sensor 142 The measured energy density of the reflected beam L2 determines the position of the condensing optical system 20. Therefore, based on the energy density of the reflected beam L2 measured by the first light sensor 142, it can be known whether the condensing point of the processing beam L1 is accurately formed on the surface of the processed object 30, and whether it is formed on a surface higher than the surface of the processed object 30 The position, or whether the processing beam L1 is reflected at the processing object 30 before forming a light-condensing point.

In FIG. 1, the distance between the position of the first light sensor 142 and the first lens portion 132 is set farther than the focal length of the first lens portion 132, but the embodiment is not limited thereto.

For example, a distance between the first light sensor 142 and the first lens portion 132 may be smaller than a focal length of the first lens portion 132. That is, in a state where the light-condensing point of the processing beam L1 is formed on the surface of the workpiece 30, the light-condensing point of the reflected beam L2 passing through the first lens portion 132 can be farther from the first light sensor than the first lens portion 132. 142. In this case, unlike FIG. 1, if the condensing point of the reflected beam L2 is close to the first lens portion 132, the energy density measured by the first light sensor 142 will increase. In addition, if the condensing point of the reflected beam L2 is far from the first lens portion 132, the energy density measured by the first light sensor 142 becomes small. That is, if the processed object 30 is far from the condensing optical system 20, the energy density measured by the first light sensor 142 increases. If the processed object 30 is close to the condensing optical system 20, the first light sensor 142 is used. The measured energy density will decrease. Therefore, the position of the condensing optical system can be determined based on the energy density of the reflected beam L2 measured by the first light sensor 142.

In FIGS. 1 to 3, the position of the light-condensing point is detected using a reflected beam reflected on the upper surface of the processed object 30, but the embodiment is not limited thereto. Figure 4 shows FIG. 1 is a diagram showing a modification of the embodiment shown in FIG. 1.

Referring to FIG. 4, the first lens portion 132 may condense the reflected beam L2 reflected on the lower surface Sd of the processed object 30. When the light transmittance of the upper surface Su of the processed object 30 is high, the intensity of the reflected beam Lu reflected on the upper surface Su of the processed object 30 is weak and it is difficult to detect the light-condensing point. In addition, if the reflected beam Lu reflected on the upper surface Su of the processed object 30 is diffused by the first beam splitter 110, it is difficult for the first lens portion 132 to collect light. In this case, as shown in FIG. 4, the first lens portion 132 condenses the reflected beam L2 that is transmitted to the inside of the processed object 30 and reflected on the lower surface Sd of the processed object 30, thereby condensing the spot detection device. The light-condensing point of the light-concentrating optical system 20 can be detected.

FIG. 5 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

Referring to FIG. 5, the condensing point detection device may further include a second beam splitter 120 that divides the reflected beam L2 into a first reflected beam L21 and a second reflected beam L22. As described with reference to FIGS. 1 to 4, the first reflected beam L21 among the light beams split by the second beam splitter 120 may be incident on the first lens portion 132. The condensing point detection device may include: a second lens portion 134 for the second reflected beam L22 to enter; and a second light sensor 144 that measures an energy density of the second reflected beam focused by the second lens portion. .

As shown in FIG. 5, if the second beam splitter 120 divides the reflected beam L2, the first reflected beam measured by the first light sensor 142 changes as the distance between the processed object 30 and the condenser optical system 20 changes. And the energy density of the second reflected beam measured by the second light sensor 144 will change together. The first light sensor 142 is The focal length of the first lens portion 132 is further away from the first lens portion 132. Conversely, the second light sensor 144 can be provided closer to the second lens portion 134 than the focal length of the second lens portion 134. As described above, if the positions of the first light sensor and the second light sensor 144 are determined, the first light sensor and the first light sensor correspond to changes in the distance between the condenser optical system 20 and the processed object 30. The sensitivity of change in energy density measured by the two-light sensor 144 becomes higher. The energy density of the light beam measured by the first light sensor 142 and the second light sensor 144 changes in different directions because the distance between the condensing optical system 20 and the processed object 30 changes, so it can be easily changed. A change in the difference between the measurement value of the first light sensor 142 and the measurement value of the second light sensor 144 was observed. In FIG. 5, the focal length of the first light sensor 142 is farther from the first lens portion 132 than the first lens portion 132, and the focal length of the second light sensor 144 is closer to the second lens than the second lens portion 134. 134, but the embodiment also includes the opposite case.

FIG. 6 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

Referring to FIG. 6, the light spot detection device may further include a mirror surface 122 that changes a path of the second reflected beam L22. As shown in FIG. 6, if the path of the second reflected beam L22 is changed, the first lens portion 132 and the second lens portion 134 can be configured to the same direction. In addition, since the first reflected beam L21 and the second reflected beam L22 travel in the same direction, the installation space of the light spot detection device can be further reduced. As shown in FIG. 6, if two or more light sensors 142 and 144 are provided, the light condensing optical system 20 and the processed object can be eliminated by comparing the light energy densities measured by the light sensors 142 and 144. In addition to the change in the distance between 30, the measured value changes due to noise and other reasons.

Different from FIG. 5, the distance 11 between the first light sensor 142 and the first lens portion 132 is greater than the focal length f1 of the first lens portion 132, and the second light sensor 144 and the second lens are shown in FIG. 6. The distance 12 between the parts 134 is also larger than the focal length f2 of the second lens part 134, but the embodiment may include other examples. For example, the distance 11 between the first light sensor 142 and the first lens portion 132 may be smaller than the focal length f1 of the first lens portion 132, and the distance between the second light sensor 144 and the second lens portion 134. 12 is also smaller than the focal length f2 of the second lens portion 134. In addition, as another example, the distance 11 between the first light sensor 142 and the first lens portion 132 may be greater than the focal length f1 of the first lens portion 132. Conversely, the second light sensor 144 and the second light sensor 144 The distance 12 between the lens portions 134 is smaller than the focal length f2 of the second lens portion 134. As another example, the distance 11 between the first light sensor 142 and the first lens portion 132 may be smaller than the focal length f1 of the first lens portion 132. Conversely, the second light sensor 144 and the second lens portion The distance 12 between 134 is larger than the focal length f2 of the second lens portion 134.

FIG. 7 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

Referring to FIG. 7, as in FIG. 5, the distance 11 between the first light sensor 142 and the first lens portion 132 may be greater than the focal length f1 of the first lens portion 132, and the second light sensor 144 and the second lens The distance 12 between the portions 134 is smaller than the focal length f2 of the second lens portion 134. As described above, if the relationship between the distance 11 and the focal distance f1 and the relationship between the distance 12 and the focal distance f2 are opposite to each other, as the distance between the condenser optical system 20 and the processed object 30 changes, the first The measurement values measured by the light sensor 142 and the second light sensor 144 change in different directions. With this, as described below, The difference between the measured values measured by the first light sensor 142 and the second light sensor 144 can be confirmed more clearly.

FIG. 8 is a diagram showing an example in which the distance between the condensing optical system 20 and the workpiece 30 shown in FIG. 7 changes.

Referring to FIG. 8, the distance between the processed object 30 and the condensing optical system 20 becomes larger than the distance shown in FIG. 7. Therefore, the light-condensing point of the processing beam L1 by the light-concentrating optical system 20 can be formed on the surface of the processed object 30. The angle of incidence of the reflection beam L2 reflected on the surface of the processed object 30 due to the light-condensing point of the processed beam L1 formed on the surface of the processed object 30 changes. In addition, as the angle of the reflected beam L2 incident on the condenser optical system 20 changes, the angle of the reflected beam L2 incident on the first beam splitter 110 also changes. In addition, the angle at which the reflected beam L2 is incident on the second beam splitter 120 also changes. As shown in FIG. 8, if the light-condensing point of the processing beam L1 is located on the surface of the processing object 30, unlike in the case of FIG. 7, the first reflected beam L21 and the second reflected beam obtained by the second beam splitter 120 are divided. The beam size of L22 will gradually decrease. In addition, the distance f1 ′ between the light-condensing point of the first reflected beam L21 and the first lens portion 132 becomes smaller than the focal length f1 of the first lens portion 132. In addition, a distance f2 ′ between the light-condensing point of the second reflected beam L22 and the second lens portion 134 becomes smaller than a focal length f2 of the second lens portion 134.

The distance f1 'between the light-condensing point of the first reflected beam L21 and the first lens portion 132, and the distance t1' between the first light sensor 142 and the light-condensing point of the first reflected beam L21 can become larger than the figure. The distance t1 shown in 7. Conversely, the distance t2 ′ between the second light sensor 144 and the light-condensing point of the second reflected beam L22 may become smaller than the distance shown in FIG. 7 t2. Therefore, if the distance between the processed object 30 and the condenser optical system 20 becomes smaller, the energy density of the first reflected beam L21 measured by the first light sensor 142 becomes smaller. The energy density of the second reflected beam L22 measured by the detector 144 increases.

FIG. 9 is a diagram showing another example in which the distance between the condensing optical system 20 and the workpiece 30 shown in FIG. 7 changes.

Referring to FIG. 9, the distance between the processed object 30 and the condensing optical system 20 becomes smaller than the distance shown in FIG. 7. Therefore, the processing beam L1 passing through the light-concentrating optical system 20 is reflected on the surface of the processed object 30 before the light-condensing point is formed. Before the processing beam L1 is reflected on the surface of the processed object 30 before the light-condensing point is formed, the angle at which the reflected beam L2 reflected on the surface of the processed object 30 enters the focusing optical system 20 changes. In addition, as the angle of the reflected beam L2 incident on the condenser optical system 20 changes, the angle of the reflected beam L2 incident on the first beam splitter 110 also changes. In addition, the angle at which the reflected beam L2 is incident on the second beam splitter 120 also changes. As shown in FIG. 9, if the processing beam L1 is reflected on the surface of the processing object 30 before forming a light-condensing point, unlike the case of FIG. 7, the first reflected beam L21 and the second reflection beam split by the second beam splitter 120 are different. The beam size of the reflected beam L22 becomes gradually larger. In addition, therefore, the distance f1 "between the focusing point of the first reflected beam L21 and the first lens portion 132 becomes larger than the focal length f1 of the first lens portion 132. Further, the focusing point of the second reflected beam L22 and A distance f2 ″ between the second lens portions 134 becomes larger than a focal length f2 of the second lens portion 134.

Distance f1 'between the light-condensing point of the first reflected beam L21 and the first lens portion 132, and distance t1 "between the first light sensor 142 and the light-condensing point of the first reflected beam L21 It may become smaller than the distance t1 shown in FIG. 7. Conversely, the distance t2 ″ between the second light sensor 144 and the light-condensing point of the second reflected beam L22 may become larger than the distance t2 shown in FIG. 7. Therefore, if the processed object 30 and the light-concentrating optical system 20 As the distance between them increases, the energy density of the first reflected beam L21 measured by the first light sensor 142 increases. On the contrary, the energy density of the second reflected beam L22 measured by the second light sensor 144 increases. The energy density will become smaller.

FIG. 10 is a graph showing changes in the energy density of the first reflected beam L21 and the energy density of the second reflected beam L22 measured by the first light sensor 142. In FIG. 10, the horizontal axis represents a change in the distance between the condenser optical system 20 and the processed object 30. On the horizontal axis, 0 point indicates the time point at which the light-condensing point of the processing beam L1 is formed to the surface of the processed object 30. On the horizontal axis, the "-" value means that the distance between the condensing optical system 20 and the processed object 30 becomes smaller than the 0 point position, and the "+" value means the distance between the condensing optical system 20 and the processed object 30 It becomes greater than 0 point position. The vertical axis represents the energy density of the light beam. In FIG. 10, the S1 curve represents the energy density of the first reflected beam L21 measured by the first light sensor 142, and the S2 curve represents the energy density of the second reflected beam L22 measured by the second light sensor 144. Energy Density. In addition, S1 to S2 represent the difference between the measurement value of the first light sensor 142 and the measurement value of the second light sensor.

Referring to FIG. 10, as the distance between the condenser optical system 20 and the processed object 30 becomes smaller, the energy density of the first reflected beam L21 measured by the first light sensor 142 becomes smaller. The energy density of the second reflected beam L22 measured by the light sensor 144 becomes larger. In addition, as the distance between the condenser optical system 20 and the processed object 30 increases, the distance of the first reflected beam L21 measured by the first light sensor 142 is increased. The energy density becomes larger, and conversely, the energy density of the second reflected beam L22 measured by the second light sensor 144 becomes smaller. As shown in FIG. 9, the energy densities of the first reflected beam L21 and the second reflected beam L22 measured by the first light sensor 142 and the second light sensor 144 depend on the condensing optical system 20 and the processed object 30. the distance between. Therefore, the relative position of the condensing optical system 20 with respect to the workpiece 30 can be determined based on the energy density measurement values of the first reflected beam L21 and the second reflected beam L22.

Illustratively, in order to determine the position of the condensing optical system 20, the difference between the measured value of the energy density of the first reflected beam L21 and the measured value of the energy density of the second reflected beam L22 may be observed. Observing the graphs S1-S2, it can be seen that as the horizontal axis value changes from 0 point on the horizontal axis, the vertical axis value changes sensitively. The reason is that the graphs S1 and S2 are changed in different directions with respect to the horizontal axis, respectively. That is, as shown in FIGS. 7 to 9, if the positions of the first light sensor 142 and the second light sensor 144 are differently arranged, the distance between the processed object 30 and the light-concentrating optical system 20 occurs. The measurement value of the first light sensor 142 and the measurement value of the second light sensor 144 change in different directions, so the measurement value of the first light sensor 142 and the second light sensor can be easily confirmed. The difference between the measured values of the controller 144.

In FIG. 10, graphs S1-S2 showing the measured values of the first light sensor 142 and the measured values of the second light sensor 144 are illustrated, but the embodiment is not limited thereto. For example, the position of the condensing optical system 20 may also be determined based on a ratio between a measurement value of the first light sensor 142 and a measurement value of the second light sensor 144. In addition, the method of comparing the measured value of the first light sensor 142 with the measured value of the second light sensor 144 can achieve various changes at a level that is relatively easy for the practitioner. more.

As shown in FIG. 5 to FIG. 9, if the focused spot detection device divides the reflected beam into two or more, the distance between the focused optical system 20 and the processed object 30 can be removed when detecting the focused spot of the processed beam. Exclude other noise factors. For example, as shown in FIG. 1 to FIG. 4, when the light spot detection device includes only the first light sensor 142, the energy density of the reflected beam L2 measured by the first light sensor 142 is divided by the light. In addition to the distance between the optical system 20 and the processed object 30, other noise factors also change. For example, the energy density of the reflected beam L2 measured by the first light sensor 142 may be caused by a change in the intensity of the processing beam L1 emitted from the light source 10, a foreign object on the laser beam traveling path, a difference in the reflectance of the processed object 30, and the like. Changed. However, as shown in FIG. 5 to FIG. 8, the reflected beam L2 is divided into two or more and the energy density of the first reflected beam L21 measured by the first light sensor 142 and the second light sensor are observed. It can be seen that the difference in energy density of the second reflected beam L22 measured by 144 can offset the above-mentioned noise factor.

11 and 12 are diagrams showing a modification example of the condensing optical system 20 shown in FIG. 5.

11, the condensing optical system 20 may include a plurality of lenses 22, 24, 26. FIG. 11 shows a case where the condensing optical system 20 includes two convex lenses 24 and 26 and one concave lens 22, but the embodiment is not limited thereto. The type and number of lenses that can be included in the condenser optical system 20 can be changed. Further, referring to FIG. 12, the condensing optical system 20 may include scanners 21 and 23 that change the path and size of the processing beam L1, and a lens 25 that changes the size of the processing beam L1. As shown in Fig. 12, the condenser optical system 20 may not focus the processing beam L1 to the processed object 30, and further increase the size of the processing beam L1 to form parallel light for emission. In this case, the light spot detection device of the embodiment can be used to diagnose the size of the processing beam L1 incident on the processing object 30 and whether the processing beam L1 becomes parallel light or the like.

FIG. 13 is a diagram schematically showing a light spot detection device according to another exemplary embodiment.

Referring to FIG. 13, the condensing point detection device may further include a third beam splitter 123 that changes a traveling direction of the second reflected beam L22, and a measurement light source 150 that emits a measurement beam L3 to the third beam splitter 123. In the embodiment shown in FIG. 5, the reflection of the processing beam L1 on the processed object 30 is used. In FIG. 13, this situation can be strengthened and the light source 150 for measurement together with the processing beam L1 is incident on the processed object 30. Measurement beam L3. In this case, if the wavelength of the measurement beam L3 and the wavelength of the processing beam L1 are set differently, the first beam splitter 110 can be configured more efficiently. The first beam splitter 110 is configured to transmit all of the processing beam L1 and selectively reflect only the measurement beam L3, and can improve the energy efficiency of the light source 10 emitting the processing beam L1. The first beam splitter 110 may reflect the entire measurement beam L3 or may reflect only a part of the measurement beam L3 and transmit the remaining beam.

In FIGS. 5 to 9, the first reflected beam L21 and the second reflected beam L22 divided by the second beam splitter 120 are focused on the first lens portion 132 and the second lens portion 134, respectively. However, when the reflected beam L2 is divided into two, the condensing point detection device may include only one lens portion.

FIG. 14 is a light spot inspection that schematically shows another exemplary embodiment. Figure of the test device.

Referring to FIG. 14, the first lens portion 132 may be disposed between the first beam splitter 110 and the second beam splitter 120. In addition, the second beam splitter 120 may divide the reflected beam L2 focused by the first lens portion 132 into a first reflected beam L21 and a second reflected beam L22. And, the condensing point detection device may include a mirror surface 122 that converts the direction of the second reflected beam L22. Although not shown, the configuration of the mirror surface 122 may be omitted. As shown in FIG. 14, if the first lens portion 132 is provided between the first beam splitter 110 and the second beam splitter 120, it is not necessary to additionally include a second lens portion 134 in order to focus the second reflected beam L22. Therefore, the configuration of the light spot detection device is further simplified.

The condensing point detection device of the exemplary embodiment has been described above. Hereinafter, a laser processing apparatus including a spot detection device will be described. As shown in FIG. 1 to FIG. 14, the laser processing apparatus can be configured to include a condensing point detection device, a light source 10, and a condensing optical system 20. The position of the condensing optical system 20 can be determined based on the energy density of the reflected beam measured by the light sensor. The position of the condensing optical system 20 can be adjusted manually or automatically by a condensing point detection device. When the position of the condensing optical system 20 is automatically adjusted, the condensing point detection device shown in FIGS. 1 to 14 can be operated as an autofocus unit.

In FIGS. 1 to 14, the case where the focusing point of the processing beam L1 is formed to the surface of the processed object 30 is shown, but the embodiment is not limited thereto. The laser processing device of the embodiment may also use a light spot detection device to form a light spot of the processing beam L1 inside the processed object 30.

FIG. 15 shows a laser processing apparatus and a processed object showing an exemplary embodiment; FIG. 30 is a diagram showing an example of a light-condensing spot of the processing beam L1 inside.

Referring to FIG. 15, the laser processing apparatus of the embodiment may include: a light source 10 that emits a processing beam L1 for laser processing toward the processing object 30; a condensing optical system 20 that focuses the processing beam L1; and an autofocus unit Adjusting the position of the above-mentioned condensing optical system so that the light-condensing point of the processing beam L1 is formed to the inside of the processed object. The above-mentioned auto-focusing unit can be implemented like the above-mentioned light spot detection device. In FIG. 15, the focus point detection device shown in FIGS. 7 to 9 is shown as an embodiment of the autofocus unit, but the embodiment is not limited thereto. The autofocus unit that can be included in the laser processing apparatus can be applied to all the embodiments described with reference to FIGS. 1 to 14.

At least a part of the processing beam L1 that has passed through the condensing optical system 20 may enter the inside of the processed object 30. In addition, other parts of the processing beam L1 may be reflected on the surface of the processed object 30. In order for the processing beam L1 to form a condensing point P inside the processed object 30, the distance between the condensing optical system 20 and the processed object 30 may be smaller than the distance shown in FIG. 5. The first light sensor 142 and the second light sensor 144 of the autofocus unit can measure the energy densities of the first reflected beam L21 and the second reflected beam L22, respectively. The autofocus unit adjusts the position of the condensing optical system 20 based on the energy densities measured by the first light sensor 142 and the second light sensor 144 so that the condensing point P of the processing beam L1 is formed to processing.物 30 的 内。 The interior of the thing 30.

FIG. 16 is an enlarged view showing a light-condensing point P forming a processing beam L1 inside the workpiece 30 shown in FIG. 15.

Referring to FIG. 16, a part of the processing beam L1 incident on the processed object 30 is reflected and returned as a reflected beam L2, and the other part is directed toward the inner portion of the processed object 30. The transmitted light beam L1 ′ can form a light-condensing point P inside the processed object 30. At this time, the following formula can be satisfied between the height d1 at which the reflection beam L2 forms a light-condensing point and the depth d2 at which the light-concentration point P is formed inside the processed object.

[Formula 1] d2 = n × d1

Here, n represents the refractive index inside the processed object 30. The refractive index outside the processed object 30 is assumed to be 1, which is the refractive index of air. Therefore, the above formula 1 is merely an example, and the embodiment is not necessarily limited thereto. Since the refractive index outside the processed object 30 is different from that of the processed object 30, according to Snell's law, the reflection angle of the reflected beam L2 and the transmission angle of the transmitted beam L1 'change. Therefore, the depth d2 at which the reflection beam L2 forms the light-condensing point P inside the processed object is greater than the height d1 at which the light-condensing point is formed.

Actually, the energy density detected by the light sensors 142, 144 of the autofocus device corresponds to the reflected beam L2. Therefore, the energy density value detected by the photo sensors 142 and 144 of the auto-focusing device will depend on the condensing point height d1 of the reflected beam L2. However, between the height d1 of the light-condensing point of the reflected beam L2 and the depth d2 forming the light-condensing point P inside the workpiece, Expression 1 described above can be satisfied. Therefore, in order to form the light-condensing point of the processing beam L1 inside the workpiece 30, the laser processing apparatus of the embodiment not only considers the energy density measured by the photo sensors 142 and 144 of the autofocus unit, but also considers the energy density. Refractive index. That is, the condensing optics can be determined based on the energy densities of the first reflected beam L21 and the second reflected beam L22 measured by the first light sensor 142 and the second light sensor 144 and the refractive index of the processed object 30. The location of the system 20.

In the above, referring to FIG. 1 to FIG. 16, the spot inspection of the exemplary embodiment is described. The test device is explained. According to the above embodiment, the reflected beam L2 reflected from the processed object 30 is focused, and the energy density of the focused reflected beam L2 is measured, whereby the position where the processing beam L1 forms a light-condensing point can be detected. In this case, instead of measuring the path of the reflected beam L2 itself, the energy density of the focused reflected beam L2 is measured. Therefore, it is possible to stably detect the strain of the condensing optical system 20 and the positional change of the workpiece 30. Condensing spot position of the processing beam L1. In addition, if the reflected beam L2 is divided into the first reflected beam L21 and the second reflected beam L22 by the second beam splitter 120, in addition to the change in the distance between the processed object 30 and the condensing optical system 20, other factors can be offset. Noise factor. In addition, by appropriately adjusting the positions of the first light sensor 142 and the second light sensor 144, the measured value measured by the first light sensor 142 and the second light sensor 144 can be measured. The difference in the measured values obtained changes sensitively with the change in the distance between the condenser optical system 20 and the workpiece 30.

In the above description, a plurality of matters are specifically described, but these matters do not limit the scope of the invention, but should be interpreted as examples of preferred embodiments. Therefore, the scope of the present invention should not be defined by the illustrated embodiments, but should be defined by the technical ideas recorded in the scope of the patent application.

10‧‧‧ light source

20‧‧‧ Condensing optical system

30‧‧‧Processed

110‧‧‧first beam splitter

132‧‧‧First lens section

142‧‧‧The first light sensor

d0‧‧‧distance

f‧‧‧ focal length

L1‧‧‧Processing beam

L2‧‧‧Reflected Beam

Claims (15)

A condensing point detection device for detecting the position of a condensing point of a laser processing beam, the condensing point detection device includes a first beam splitter, a laser light source provided to emit the processing beam, and processing the processing point. At least a part of the reflected beam reflected from the processing object is reflected between the condensing optical systems for condensing the beam; the first lens unit focuses the reflected beam reflected from the first beam splitter; and A first light sensor configured to measure an energy density of the reflected beam focused by the first lens portion from the first lens portion disposed in a direction in which the reflected beam is focused, and incident on the A ratio of an incident light beam of the first photosensor to the reflected beam focused from the first lens portion changes according to the position of the light-condensing point. The condensing point detection device according to item 1 of the scope of the patent application, wherein the position of the condensing optical system is determined based on the energy density of the reflected beam measured by the first light sensor. The condensing point detection device according to item 1 of the patent application scope, further comprising a second beam splitter that divides the reflected beam reflected from the first beam splitter into a first reflection Beam and second reflected beam. The condensing point detection device according to item 3 of the scope of patent application, wherein the first reflected beam is incident on the first lens portion, and the condensing point detection device includes a second lens portion for the first Two reflection beam Incident; and a second light sensor disposed from the second lens portion in a direction in which the second reflected beam is focused, to an energy density of the second reflected beam focused by the second lens portion Perform the measurement. The condensing point detection device according to item 4 of the scope of patent application, wherein according to the energy density of the first reflected beam measured by the first light sensor and the second light sensor The position of the condensing optical system is measured by measuring the energy density of the second reflected beam. The condensing point detection device according to item 5 of the scope of patent application, wherein the position of the condensing optical system is determined based on a difference between the energy density of the first reflected beam and the energy density of the second reflected beam. The condensing point detection device according to item 4 of the scope of patent application, wherein the first light sensor is disposed away from the first lens portion with a focal length longer than the focal length of the first lens portion, and the second The light sensor is provided so as to be closer to the second lens portion than a focal length of the second lens portion. The condensing point detection device according to item 4 of the scope of patent application, wherein the first light sensor is disposed closer to the first lens portion than a focal length of the first lens portion, and the second The light sensor is disposed farther from the second lens portion than the second lens portion. The condensing point detection device according to item 4 of the scope of patent application, further comprising: a third beam splitter that changes the second reflection obtained by the second beam splitter. A traveling direction of the beam; and a light source for measurement, which emits the light beam for measurement to the third beam splitter. The condensing point detection device according to item 9 of the scope of the patent application, wherein the first beam splitter reflects at least a part of a reflected beam reflected by the measurement beam on the processing object. According to the condensing point detection device according to item 9 of the scope of application for a patent, wherein a wavelength of a measurement beam emitted from the measurement light source is different from a wavelength of light emitted from the laser light source, the first beam splitting The device transmits light emitted from the laser light source, and reflects a measurement light beam emitted from the measurement light source. The condensing point detection device according to item 1 of the scope of patent application, further comprising a second beam splitter that divides the reflected beam focused by the first lens section into The first reflected beam and the second reflected beam. The condensing point detection device according to item 12 of the scope of the patent application, wherein the first light sensor is set to a travel path of the first reflected beam to measure an energy density of the first reflected beam. The condensing point detection device according to item 13 of the scope of the patent application, further comprising a second light sensor, the second light sensor is set to a travel path of the second reflected beam, and The energy density of the two reflected beams was measured. The condensing point detection device according to item 14 of the scope of application for a patent, wherein according to the energy density of the first reflected beam measured by the first light sensor and the second light sensor Measured by measuring the energy density of the second reflected beam The position of the condensing optical system is determined.