In-plane measuring instrument device and laser processing equipment

Abstract

The invention provides an in-plane measuring instrument device which is characterized in that the in-plane measuring instrument device comprises a first pair of reflectors which are suitable for reflecting object light, and the object light is light reflected by an object to be measured when incident light irradiates the object to be measured; the first pair of reflectors is arranged on the detector, the first offset mechanism is suitable for enabling at least one reflector in the first pair of reflectors to offset, so that the two beams of object light reflected by the first pair of reflectors can form a shearing amount along an x direction on the detector to generate shearing interference, and the x direction belongs to an in-plane direction; the focus lens is arranged at the downstream of the first pair of reflectors so that the two beams of object light reflected by the first pair of reflectors can be focused on the detector through the focus lens. The invention particularly relates to a corresponding laser processing device. The shearing device has the advantages that shearing interference can be achieved with a simple structure, and the shearing amount can be adjusted more conveniently.

Description

Technical Field

[0001] The present application relates to an in-plane measuring device and a laser processing equipment. Background Art

[0002] After laser processing a material, residual stress typically forms in the material. This residual stress can be used to determine whether the laser processing parameters, such as laser power, feed rate, focal spot diameter, focal spot shape, and / or focal spot position, are suitable. Residual stress can also be assessed by measuring the material's strain.

[0003] Currently, it is known to use shearing speckle interferometer to measure strain. Current shearing speckle interferometers generally use a special shearing device to achieve shearing. Summary of the Invention

[0004] The object of the present application is to provide an in-plane measuring instrument device, which can save a special shearing device.

[0005] According to a first aspect of the present application, an in-plane measuring instrument device is provided, characterized in that the in-plane measuring instrument device comprises:

[0006] a first pair of reflectors, the first pair of reflectors being adapted to reflect object light, the object light being light reflected by the object to be measured when incident light illuminates the object to be measured;

[0007] a first offset mechanism, wherein the first offset mechanism is adapted to offset at least one of the first pair of reflectors so that the two object beams reflected by the first pair of reflectors can form a shear amount along the x-direction on the detector to cause shear interference, where the x-direction is an in-plane direction; and

[0008] A focusing mirror is arranged downstream of the first pair of reflecting mirrors so that the two beams of object light reflected by the first pair of reflecting mirrors can be focused onto the detector via the focusing mirror.

[0009] This particularly includes: the two beams of object light reflected by the first pair of reflectors are emitted directly to the focusing mirror; or the two beams of object light are emitted to the focusing mirror after passing through other optical devices. The x direction can be any direction within the plane.

[0010] According to an optional embodiment of the present application, the first pair of reflectors includes a first reflector for reflecting a first object light among the object light and a second reflector for reflecting a second object light among the object light.

[0011] According to an optional embodiment of the present application, the in-plane measurement device includes a beam guiding device, which is suitable for guiding the two beams of object light reflected by the first pair of reflectors toward the focusing mirror.

[0012] According to an optional embodiment of the present application, the in-plane measuring instrument device includes a second pair of mirrors and a second offset mechanism, and the second offset mechanism is suitable for offsetting at least one reflector in the second pair of reflectors so that the two beams of object light reflected by the second pair of reflectors can form a shear amount along the y direction on the detector and cause shear interference, where y is an in-plane direction perpendicular to the x direction, and the second pair of reflectors includes a third reflector for reflecting a third object light in the object light and a fourth reflector for reflecting a fourth object light in the object light.

[0013] According to an optional embodiment of the present application, the in-plane measuring instrument device includes a spatial phase shifting device or a spatial carrier phase shifting device for performing phase reconstruction on the object light reflected by the object to be measured.

[0014] According to an optional embodiment of the present application, the in-plane measuring instrument device includes an irradiation device, which is used to illuminate the object to be measured with incident light along a z direction, where the z direction is an out-of-plane direction perpendicular to the x direction.

[0015] According to an optional embodiment of the present application, the first reflector and the second reflector are arranged symmetrically with respect to the position of the incident light in the x-direction.

[0016] According to an optional embodiment of the present application, the first offset mechanism includes a first pivot module suitable for pivoting the first reflector around a first pivot axis along the y direction and / or a second pivot module suitable for pivoting the second reflector around a second pivot axis along the y direction.

[0017] According to an optional embodiment of the present application, the third reflector and the fourth reflector are arranged symmetrically with respect to the position of the incident light in the y direction.

[0018] According to an optional embodiment of the present application, the second offset mechanism includes a third pivot module suitable for pivoting the third reflector around a third pivot axis along the x-direction and / or a fourth pivot module suitable for pivoting the fourth reflector around a fourth pivot axis along the x-direction.

[0019] According to an optional embodiment of the present application, the distances between the first reflector, the second reflector, the third reflector, and the fourth reflector and the optical axis of the incident light are equal or different.

[0020] According to an optional embodiment of the present application, the in-plane measurement device includes a first polarization device for linearly polarizing a first object light along a first direction, a second polarization device for linearly polarizing a second object light along the first direction, a third polarization device for linearly polarizing a third object light along a second direction, and a fourth polarization device for linearly polarizing a fourth object light along the second direction, wherein the first direction is perpendicular to the second direction. These polarization devices may be independent of each other or integrated with each other.

[0021] According to an optional embodiment of the present application, the illumination device includes a coherent light source, which is a single coherent light source or includes two coherent light sources, and the two coherent light sources are used to emit coherent light of different wavelengths.

[0022] According to an optional embodiment of the present application, the coherent light source is a laser.

[0023] According to an optional embodiment of the present application, the illumination device includes a beam expansion device located downstream of the coherent light source, for expanding the light emitted by the coherent light source.

[0024] According to an optional embodiment of the present application, the irradiation device includes an initial reflector located downstream of the beam expanding device, and the initial reflector is used to reflect the coherent light expanded by the beam expanding device onto the object to be measured.

[0025] According to an optional embodiment of the present application, the spatial phase shifting device includes at least one of a pixelated phase mask, a spatial light modulator, and a liquid crystal array.

[0026] According to an optional embodiment of the present application, the spatial carrier phase shifting device includes at least one of a multi-aperture mask and an adjustable aperture multiplexing device.

[0027] According to an optional embodiment of the present application, the spatial carrier phase shifting device includes a first aperture with adjustable aperture for the first object light, a second aperture for the second object light, a third aperture for the third object light and / or a fourth aperture for the fourth object light.

[0028] According to an optional embodiment of the present application, the first aperture is arranged upstream of the first reflector.

[0029] According to an optional embodiment of the present application, the second aperture is arranged upstream of the second reflector.

[0030] According to an optional embodiment of the present application, the third aperture is arranged upstream of the third reflecting mirror.

[0031] According to an optional embodiment of the present application, the fourth aperture is arranged upstream of the fourth reflecting mirror.

[0032] According to an optional embodiment of the present application, the light beam guiding device includes a right-angle prism, which has a first reflecting surface for reflecting the first object light reflected by the first reflecting mirror toward the focusing mirror, a second reflecting surface for reflecting the second object light reflected by the second reflecting mirror toward the focusing mirror, a third reflecting surface for reflecting the third object light reflected by the third reflecting mirror toward the focusing mirror and / or a fourth reflecting surface for reflecting the fourth object light reflected by the fourth reflecting mirror toward the focusing mirror.

[0033] According to an optional embodiment of the present application, the in-plane measuring instrument device includes an analysis and processing device, which is configured to perform Fourier transform on the light intensity data recorded by the detector, filter out a first spectrum of interference between the conjugate light of the first object light and the second object light, and extract first phase difference information between the first object light and the second object light based on the first spectrum, and / or filter out a second spectrum of interference between the conjugate light of the third object light and the fourth object light, and extract second phase difference information between the third object light and the fourth object light based on the second spectrum.

[0034] According to an optional embodiment of the present application, the in-plane measurement device includes the detector.

[0035] According to an optional embodiment of the present application, the in-plane measurement device includes an optical filter for filtering stray light.

[0036] According to an optional embodiment of the present application, the in-plane measuring instrument device is used to measure in-plane strain, in-plane displacement and / or in-plane stress.

[0037] According to an optional embodiment of the present application, the detector is a CCD camera device.

[0038] According to an optional embodiment of the present application, the optical filter is arranged upstream of the focusing mirror.

[0039] According to a second aspect of the present application, a laser processing device is provided, characterized in that the laser processing device includes a laser processing unit and the aforementioned in-plane measuring instrument device.

[0040] According to an optional embodiment of the present application, the in-plane measuring instrument device includes a first in-plane measuring instrument device before the laser processing unit along the feeding direction of the laser processing unit and a second in-plane measuring instrument device after the laser processing unit along the feeding direction of the laser processing unit.

[0041] According to an optional embodiment of the present application, the laser processing unit is used for laser hardening processing, laser welding processing and / or laser cutting processing.

[0042] According to an optional embodiment of the present application, the laser processing equipment includes a controller, and the controller is used to adjust the processing parameters of the laser processing unit based on the measurement data of the in-plane measuring device.

[0043] According to an optional embodiment of the present application, the laser processing equipment includes an analysis and processing device. For a processing area on a workpiece, the first measurement data of the processing area is obtained by the first in-plane measuring instrument device before processing, and the second measurement data of the processing area is obtained by the second in-plane measuring instrument device after processing by the laser processing unit. The analysis and processing device is configured to derive in-plane strain through correlation operations of the first measurement data and the second measurement data.

[0044] According to an optional embodiment of the present application, the laser processing equipment includes an analysis and processing device, which is configured to derive the in-plane strain by performing correlation operations on measurement data of the same in-plane measuring device at different time frames. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present application will be described in more detail below with reference to the accompanying drawings, so that the principles, features and advantages of the present application can be better understood. The accompanying drawings include:

[0046] Figure 1 A first example of the in-plane measurement instrument device of the present application is schematically shown.

[0047] Figure 2 A second example of the in-plane measurement instrument device of the present application is schematically shown.

[0048] Figure 3 A third example of the in-plane measurement instrument device of the present application is schematically shown.

[0049] Figure 4 An example of the laser processing equipment of the present application is schematically shown.

[0050] Figure 5 Schematically shows the Figure 2 An example of the layout of a virtual four-aperture mask composed of four virtual apertures of a single aperture stop.

[0051] Figure 6 The synthetic spectral distribution of the four-beam shearing speckle pattern is schematically shown.

[0052] Figure 7 The synthetic spectral distribution of the four-beam shearing speckle pattern in the case of mutually perpendicular linear polarization is schematically shown.

[0053] Figure 8 An example of selection of the cut-off frequency is schematically shown.

[0054] Figure 9 The processing area of ​​the laser processing unit and the observation area of ​​the in-plane measuring instrument at different time frames are schematically shown. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by this application more clearly understood, this application will be further described in detail below with reference to the accompanying drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit the scope of protection of this application.

[0056] Figure 1 A first example of an in-plane measuring instrument device of the present application is schematically shown. As is well known, "in-plane" refers to the plane in which the surface of the object to be measured 100 is located. This plane is generally considered to be the xy plane, while the direction perpendicular to the xy plane is the out-of-plane direction, generally referred to as the z-direction. The in-plane measuring instrument device is particularly used to measure in-plane strain, in-plane displacement, and / or in-plane stress. The in-plane strain may particularly relate to in-plane strain in the material caused by residual stress induced by laser processing.

[0057] like Figure 1 As shown, the in-plane measuring device includes:

[0058] a first pair of reflectors 11, wherein the first pair of reflectors 11 is adapted to reflect object light 16, wherein the object light 16 is light reflected by the object 100 when the incident light 60 illuminates the object 100;

[0059] a first offset mechanism 14 adapted to offset at least one of the first pair of reflectors 11 so that the two object beams 161 reflected by the first pair of reflectors 11 can generate shear interference along an x-direction on the detector 119, where the x-direction is an in-plane direction; and

[0060] A focusing mirror 118 is arranged downstream of the first pair of reflecting mirrors 11 so that the two beams of object light 161 reflected by the first pair of reflecting mirrors 11 can be focused onto the detector 119 via the focusing mirror 118 .

[0061] The deflection can, in particular, involve pivoting and / or translation, and in particular, can only involve pivoting. The aforementioned configuration of the in-plane measuring device makes it possible to eliminate the need for a conventional dedicated shearing device. Furthermore, it has been unexpectedly discovered that the desired shearing amount can be adjusted particularly well by combining the focusing lens 118 with the first deflection mechanism 14. This is because the deflection step size of the first deflection mechanism 14, which would otherwise be difficult to achieve directly, can effectively achieve the desired shearing amount after being scaled by the focusing lens 118.

[0062] According to an exemplary embodiment of the present application, Figure 1 As shown, the first pair of reflectors 11 includes a first reflector 111 for reflecting a first object light 121 in the object light 16 and a second reflector 112 for reflecting a second object light 122 in the object light 16 .

[0063] According to an exemplary embodiment of the present application, Figure 1 As shown, the first reflector 111 and the second reflector 112 are arranged symmetrically in the x direction with respect to the incident light 60. This facilitates arrangement and simplifies the structure. Other arrangements of the first reflector 111 and the second reflector 112 are also conceivable. Figure 1 In the case of different arrangements, additional beam guiding elements such as mirrors can also be provided in the beam path.

[0064] In addition, especially when the first reflector 111 and the second reflector 112 are arranged symmetrically in the x-direction, the focusing mirror 118 makes it convenient to directly form shearing light with the first object light 121 reflected by the first reflector 111 and the second object light 122 reflected by the second reflector 112, without the need to decompose the first object light 121 or the second object light 122 into two beams of light that can shear and interfere with each other through a special shearing device.

[0065] According to an exemplary embodiment of the present application, Figure 1 As shown, the first offset mechanism 14 includes a first pivoting module 141 adapted to pivot the first reflector 111 about a first pivot axis along the y-direction and / or a second pivoting module 142 adapted to pivot the second reflector 112 about a second pivot axis along the y-direction. In the pivoting state, the first reflector 111 and the second reflector 112 can be adjusted faster and with higher precision.

[0066] According to an exemplary embodiment of the present application, Figure 1 As shown, the in-plane measuring instrument device includes an irradiation device 15 , which is used to irradiate the object to be measured 100 with incident light 60 along the z direction, and in particular, to irradiate the object to be measured 100 vertically.

[0067] According to an exemplary embodiment of the present application, Figure 1 As shown, the in-plane measuring instrument device includes a beam guiding device 115, which is suitable for guiding the two beams of object light 161 reflected by the first pair of reflectors 11 toward the focusing mirror 118. The beam guiding device 115 is particularly used to guide the two beams of object light 161 reflected by the first pair of reflectors 11 to be parallel to each other.

[0068] Here, for example, Figure 1 As shown, the beam guiding device 115 includes a right-angle prism. The right-angle prism has a first reflecting surface for reflecting the first object light 121 reflected by the first reflector 111 toward the focusing mirror 118, and a second reflecting surface for reflecting the second object light 122 reflected by the second reflector 112 toward the focusing mirror 118. The right-angle prism is particularly suitable for the case where the first reflector 111 and the second reflector 112 are arranged symmetrically in the x-direction. In other arrangements of the first reflector 111 and the second reflector 112, the beam guiding device 115 can also have other structural forms.

[0069] According to an exemplary embodiment of the present application, Figure 1 As shown, the in-plane measuring device includes the detector 119. The detector 119 can be a CCD camera device.

[0070] Figure 2 A second example of the in-plane measurement instrument device of the present application is schematically shown.

[0071] According to an exemplary embodiment of the present application, Figure 2 As shown, the in-plane measuring instrument device includes a second pair of mirrors 12 and a second offset mechanism, and the second offset mechanism is suitable for offsetting at least one of the second pair of mirrors 12 so that the two beams of object light 162 reflected by the second pair of mirrors 12 can form a shear amount along the y direction on the detector 119 and cause shear interference, where y is an in-plane direction perpendicular to the x direction, and the second pair of mirrors 12 includes a third reflector 113 for reflecting the third object light 123 in the object light 16 and a fourth reflector 114 for reflecting the fourth object light 124 in the object light 16.

[0072] This makes it possible to easily perform two-dimensional in-plane measurements.

[0073] According to an exemplary embodiment of the present application, Figure 2 As shown, the third reflector 113 and the fourth reflector 114 are arranged symmetrically with respect to the incident light 60 in the y direction.

[0074] Here, the distances between the first reflecting mirror 111 , the second reflecting mirror 112 , the third reflecting mirror 113 , and the fourth reflecting mirror 114 and the optical axis of the incident light 60 may be equal or different.

[0075] According to an exemplary embodiment of the present application, see Figure 2The second offset mechanism includes a third pivot module adapted to pivot the third reflector 113 around a third pivot axis along the x-direction and / or a fourth pivot module adapted to pivot the fourth reflector 114 around a fourth pivot axis along the x-direction.

[0076] According to an exemplary embodiment of the present application, Figure 2 As shown, the in-plane measuring device includes a spatial carrier phase shifting device 116 for performing phase reconstruction on the object light 16 reflected by the object 100. Here, the spatial carrier phase shifting device 116 can particularly include at least one of a multi-aperture mask and an adjustable aperture multiplexing device. Figure 2 In the embodiment, the spatial carrier phase shifting device 116 includes a first aperture 131 with adjustable aperture for the first object light 121, a second aperture 132 for the second object light 122, a third aperture 133 for the third object light 123, and / or a fourth aperture 134 for the fourth object light 124. These four apertures are in particular single aperture apertures with adjustable apertures. Figure 2 In the embodiment, for example, the first aperture 131 is arranged upstream of the first reflector 111, the second aperture 132 is arranged upstream of the second reflector 112, the third aperture 133 is arranged upstream of the third reflector 113, and the fourth aperture 134 is arranged upstream of the fourth reflector 114. Obviously, other arrangements of these apertures in the optical path are also conceivable. In addition, instead of Figure 2 In addition to the physical aperture shown in , digital apertures are also conceivable.

[0077] Alternatively or additionally, the in-plane measuring device includes a spatial phase shifting device for reconstructing the phase of the object light 16 reflected by the object 100. The spatial phase shifting device may include at least one of a pixelated phase mask, a spatial light modulator, and a liquid crystal array.

[0078] In particular, dynamic phase reconstruction and online in-situ measurement can be achieved by means of the spatial carrier phase shifting device 116 and / or the spatial phase shifting device.

[0079] According to an exemplary embodiment of the present application, Figure 2 As shown, in addition to the first and second reflective surfaces, the right-angle prism or beam guiding device 115 further includes a third reflective surface for reflecting the third object light 123 reflected by the third reflective mirror 113 toward the focusing mirror 118, and a fourth reflective surface for reflecting the fourth object light 124 reflected by the fourth reflective mirror 114 toward the focusing mirror 118. Here, the right-angle prism is particularly in the shape of a regular square pyramid. After being reflected by the right-angle prism, the first to fourth object lights 121 to 124 can be parallel to each other.

[0080] According to an exemplary embodiment of the present application, Figure 2 As shown, the illumination device 15 includes a coherent light source 101, which is a single coherent light source 101. Here, the coherent light source 101 can be a laser. The light emitted by the single coherent light source 101 is irradiated onto the object to be measured 100 to generate first object light 121 to fourth object light 124.

[0081] Alternatively, the coherent light source 101 may include two coherent light sources 101 configured to emit coherent light of different wavelengths. It is conceivable that the first coherent light source 101 of the two coherent light sources 101 may be configured to measure in-plane strain along the x-direction, while the second coherent light source 101 may be configured to measure in-plane strain along the y-direction.

[0082] According to an exemplary embodiment of the present application, Figure 2 As shown, the irradiation device 15 includes a beam expander 102 located downstream of the coherent light source 101, for expanding the light emitted by the coherent light source 101. The beam expander 102 can improve the uniformity of the light beam, thereby facilitating interference.

[0083] According to an exemplary embodiment of the present application, Figure 2 As shown, the illumination device 15 includes an initial reflector 110 located downstream of the beam expander 102. The initial reflector 110 is used to reflect the coherent light expanded by the beam expander 102 onto the object under test 100. The initial reflector 110 allows the coherent light source 101 and the beam expander 102 to be arranged at a side position, thereby obtaining greater design freedom.

[0084] According to an exemplary embodiment of the present application, Figure 2 As shown, the in-plane measurement device includes an optical filter 117 for filtering stray light. The stray light refers in particular to light from the laser processing process. The optical filter 117 can be arranged upstream of the focusing mirror 118, and in particular, between the right-angle prism and the focusing mirror 118.

[0085] According to an exemplary embodiment of the present application, the in-plane measuring device includes an analysis and processing device configured to perform Fourier transform on the light intensity data recorded by the detector 119, filter out a first spectrum 512 of the interference of the conjugate light of the first object light 121 and the second object light 122, and extract first phase difference information of the first object light 121 and the second object light 122 based on the first spectrum 512, and / or filter out a second spectrum 534 of the interference of the conjugate light of the third object light 123 and the fourth object light 124, and extract second phase difference information of the third object light 123 and the fourth object light 124 based on the second spectrum 534. For this, please refer to Figure 6 Description.

[0086] Figure 3 A third example of the in-plane measurement instrument device of the present application is schematically shown.

[0087] exist Figure 3 In, with Figure 2 Differently, a spatial phase shifter or spatial carrier phase shifter 116 is arranged between the beam guiding device 115, in particular the right-angle prism, and the optical filter 117. Figure 2 The aperture is arranged between the object to be measured 100 and the reflecting mirror. Figure 3 Other structures of the in-plane measuring instrument device can refer to Figure 2 The description of , will not be repeated here one by one.

[0088] Figure 4 An example of the laser processing equipment of the present application is schematically shown.

[0089] See also Figure 4 , the laser processing equipment includes a laser processing unit 310 and at least one of the aforementioned in-plane measuring instrument devices.

[0090] According to an exemplary embodiment of the present application, the laser processing unit 310 can be used for laser hardening processing, laser welding processing and / or laser cutting processing. The laser cutting processing can involve cutting of metal or brittle materials, especially glass.

[0091] According to an exemplary embodiment of the present application, the laser processing apparatus includes a controller configured to adjust processing parameters of the laser processing unit 310 based on measurement data of the in-plane measuring device.

[0092] According to an exemplary embodiment of the present application, Figure 4As shown, the laser processing equipment includes a first in-plane measuring instrument device 311 before the laser processing unit 310 along the feed direction v of the laser processing unit 310 and a second in-plane measuring instrument device 312 after the laser processing unit 310 along the feed direction v of the laser processing unit 310. The feeding of the laser processing unit 310 may especially involve any one of the following three situations: the workpiece (or the object to be measured 100) is stationary, and the laser processing unit 310 moves along the feed direction v; the laser processing unit 310 is stationary, and the workpiece moves, so that the laser processing unit 310 moves relative to the workpiece along the feed direction v; both the workpiece and the laser processing unit 310 move. The feed direction v especially involves the direction in the xy plane. Figure 4 In FIG. 3 , the current observation area 321 of the first in-plane measuring instrument device 311 and the current observation area 322 of the second in-plane measuring instrument device 312 can be seen.

[0093] According to an exemplary embodiment of the present application, the laser processing apparatus includes an analysis and processing device. For a processing region on a workpiece, the first in-plane measuring device 311 acquires first measurement data of the processing region before processing, and the second in-plane measuring device 312 acquires second measurement data of the processing region after processing by the laser processing unit 310. The analysis and processing device is configured to derive in-plane strain through a correlation operation of the first and second measurement data. The measurement data, for example, may be a shear speckle pattern, and in particular, a light intensity image or a grayscale speckle image captured by a CCD camera.

[0094] In the back Figure 4 As an example, an exemplary working mode of the in-plane measuring device of the laser processing equipment of the present application is described. Here, the in-plane measuring device is, for example, Figure 2 In-plane measurement instrument device.

[0095] When the laser processing equipment is working, the first in-plane measuring device 311 and the second in-plane measuring device 312 work independently of each other and continuously capture shear speckle patterns at a preset capture frequency. For the same observation area or processing area, the first in-plane measuring device 311 acquires the first shear speckle pattern I before processing. before (x n ,y n ), after processing, the second shear speckle pattern I is obtained by the second in-plane measuring device 312 after (x n ,y n ). The speckle fringe pattern I can be obtained by performing correlation operation on the two sheared speckle images, such as subtraction. fringe (x n ,y n). This can be seen, for example, in formula (1):

[0096] I fringe (x n ,y n )=I after (x n ,y n )-I before (x n ,y n ) (1)

[0097] During the processing, as the laser processing unit 310 moves, the first shear speckle pattern I before (x n ,y n ) and the second shear speckle pattern I aftet (x n ,y n ) is continuously updated. The first and second shear speckle patterns with the same coordinate parameters are selected in pairs for subsequent data processing. Furthermore, it is conceivable to display the strain field on the object under test 100, particularly a workpiece to be laser processed, in real time on a monitor in the form of a speckle fringe pattern.

[0098] In each in-plane measuring instrument device, based on the positional symmetry of the first and second reflective mirrors 111, 112, and the third and fourth reflective mirrors 113, 114, the observation angles for the first and second object beams 121, 122 are both α, while the observation angles for the third and fourth object beams 123, 124 are both β. This allows the introduction of two orthogonal sensitivity vectors, and the in-plane strain ε(ε x ,ε y ) is the wavelength λ of the coherent light, the unwrapped phase change diagram Δφ of the shear speckle pattern caused by the workpiece deformation caused by laser processing (Δφ x ,Δφ y ), shear amount Δs(Δs x ,Δs y 0 and the function of the observation angles α and β. The in-plane strain components can be calculated by formulas (2) and (3) respectively. In order to simplify the expression, the coordinate parameters (x n ,y n ) is not listed in the following formula.

[0099]

[0100] The composite in-plane strain ε is calculated according to the following formula (4):

[0101]

[0102] In the shear amount Δs(Δs x,Δs y ) is zero, the in-plane displacement introduced during laser processing can be calculated using the following formulas (5) and (6):

[0103]

[0104] Due to the requirement for real-time performance of the measurement system, the adjustable aperture multiplexing (AAM) technology combined with Fourier transform (FTM) is used to simultaneously and dynamically obtain the phase change distribution Δφ caused by residual stress. x and Δφ y Six pairs of adjustable spatial carrier frequencies can be introduced through the first to fourth apertures 131 to 134 with adjustable apertures, so that a total of six sheared speckle patterns generated by two object beams 16 can be transmitted in frequency ranges independent of each other and evaluated independently of each other.

[0105] The light intensity I of the interference speckle pattern before and after laser processing can be expressed by formula (7)

[0106]

[0107] in,

[0108] u=|u|e jφ

[0109] Here, |u| represents the amplitude modulus of the wave, and φ represents the phase. * represents the complex conjugate of u. Indexes 1 to 4 represent the first object light 121 to the fourth object light 124 respectively.

[0110] After applying the fast Fourier transform (u becomes U), the intensity image is converted from the spatial domain to the frequency domain, which is expressed by formula (8).

[0111]

[0112] in, is the Fourier operator, Represents the convolution operator.

[0113] Since there are a total of four object beams 16 and six adjustable spatial carrier frequencies in each in-plane measurement instrument, there are many possibilities for the spectral distribution of the recorded shear speckle pattern. In order to obtain the required phase map of the shear speckle pattern, the selection of the spatial carrier frequency must meet the following requirements:

[0114] The spectrum of the required sheared speckle pattern must be completely separate and independent from the spectra of other sheared speckle patterns;

[0115] ● All useful spectra should be confined to the maximum spatial frequency of the detector 119;

[0116] • The cutoff frequency should be optimized to achieve the best spatial resolution in the resulting phase image.

[0117] Figure 5 Schematically shows the Figure 2 An example of the layout of a virtual four-aperture mask 400 composed of the virtual apertures of four single-aperture apertures is shown. Here, we can see the first virtual aperture 411 of the first aperture 131, the second virtual aperture 412 of the second aperture 132, the third virtual aperture 413 of the third aperture 133, and the fourth virtual aperture 414 of the fourth aperture 134. Here, the first and second virtual apertures 411 and 412 are offset from the origin in the x-direction, while the third and fourth virtual apertures 413 and 414 are offset from the origin in the y-direction. These four virtual apertures are offset equidistantly from the origin of the virtual four-aperture mask 400.

[0118] Figure 6 The synthetic spectral distribution of the four-beam shearing speckle pattern is schematically shown. x Characterizes the frequency in the x direction, f y Characterizes the frequency in the y direction. Figure 6 In particular, it can be seen as Figure 5 Here, 512 represents the first spectrum And 534 represents the second spectrum

[0119] Before and after the laser processing process, the first spectrum 512 and the second spectrum 534 are filtered out of the spectral distribution and the in-plane wrapped phase image is reconstructed by inverse Fourier transformation (U becomes u) and This is done by equations (9) and (10)

[0120]

[0121]

[0122] Before laser processing, the in-plane wrapping phase image is After laser processing, the in-plane wrapping phase image is By unpacking the operator The continuously distributed unwrapped phase change diagram Δφ(Δφ x ,Δφ y ). This is expressed by formulas (11) and (12):

[0123]

[0124] Finally, for example, the value of the coordinate (x n ,y n ) in-plane strain ε(ε x ,ε y ). If necessary, the corresponding in-plane stress σ(σ x ,σ y ).

[0125] According to an exemplary embodiment of the present application, the in-plane measurement device includes a first polarization device for linearly polarizing first object light 121 along a first direction, a second polarization device for linearly polarizing second object light 122 along the first direction, a third polarization device for linearly polarizing third object light 123 along a second direction, and a fourth polarization device for linearly polarizing fourth object light 124 along the second direction, wherein the first direction is perpendicular to the second direction. The first through fourth polarization devices can be arranged at any suitable location downstream of the object under test 100. Alternatively, it is conceivable that, in the presence of two coherent light sources, the light emitted by these two coherent light sources is already polarized perpendicularly to each other upstream of the object under test.

[0126] By the above method, the spectral distribution of the sheared speckle pattern can be expressed by formula (13) instead of formula (8):

[0127]

[0128] Here, the first object light 121 , the second object light 122 , and the conjugate light thereof do not interfere with the third object light 123 , the fourth object light 124 , and the conjugate light thereof based on linear polarization in directions perpendicular to each other.

[0129] Figure 7 The synthetic spectrum distribution of the four-beam shearing speckle pattern under mutually perpendicular linear polarization is schematically shown. Here, the first spectrum 512 and the second spectrum 534 are filtered out for subsequent data processing.

[0130] Figure 8 An example of selection of the cut-off frequency is schematically shown.

[0131] In the case of polarization, if the conditions of spectrum separation and independence are met, such as Figure 8 As shown in FIG, the cutoff frequency can be increased, thereby making the obtained phase change image have a higher spatial resolution, thereby achieving higher measurement accuracy.

[0132] Figure 9The schematic diagram shows the processing areas of the laser processing unit 310 and the observation areas of the in-plane measuring instrument at different time frames. Here, it can be seen that the laser processing unit 310 is in processing area 800 in the first time frame, the laser processing unit 310 is in processing area 810 in the second time frame, the first in-plane measuring instrument device 311 is in observation area 801 in the first time frame, the first in-plane measuring instrument device 311 is in observation area 811 in the second time frame, the second in-plane measuring instrument device 312 is in observation area 802 in the first time frame, and the second in-plane measuring instrument device 312 is in observation area 812 in the second time frame.

[0133] According to an exemplary embodiment of the present application, see Figure 9 The laser processing apparatus includes an analysis and processing device configured to derive in-plane strain by performing a correlation operation on measurement data from the same in-plane measuring instrument device (first in-plane measuring instrument device 311 or second in-plane measuring instrument device 312) at different time frames. The correlation operation is, in particular, subtraction. This allows the strain distribution before and after laser processing to be evaluated. Thus, in particular by appropriately setting the relative relationship between the image capture frequency and the laser processing speed, it is possible to measure in-plane strain during the preheating process (via the first in-plane measuring instrument device 311) and the cooling process (via the second in-plane measuring instrument device 312) accompanying the laser processing process.

[0134] In this context, the in-plane metrology device may be a component of the in-plane metrology device or directly the in-plane metrology device itself.

[0135] As long as it is permitted in principle, each of the features listed can be considered to be independent and can be combined with any other features in any form without departing from the scope of protection of this application. If it is permitted in principle, even if not directly mentioned, the features described for one embodiment should be considered to be applicable to other embodiments at will.

[0136] In the drawings, among multiple elements with the same function, only some of them are exemplarily labeled. However, those skilled in the art can undoubtedly identify other elements with the same function based on the similarity between the shapes of these elements.

[0137] In this context, the concept "light reflected by the object to be measured" should be understood to encompass not only light directly reflected by the object to be measured, but also light directly reflected by the object to be measured can still be considered "light reflected by the object to be measured" even after propagating through other optical components. Similarly, the concept "two beams of object light reflected by the first pair of reflectors" should be understood to encompass not only the two beams of object light directly reflected by the first pair of reflectors, but also light directly reflected by the first pair of reflectors can still be considered "light reflected by the first pair of reflectors" even after propagating through other optical components. Similar concepts should also be understood in this manner, and will not be elaborated on here.

[0138] Although specific embodiments of the present application are described in detail herein, they are provided for illustrative purposes only and should not be considered to limit the scope of the present application. Various replacements, changes, and modifications may be conceived without departing from the spirit and scope of the present application.

[0139] Reference Signs List

[0140] 11 The first pair of mirrors

[0141] 12 Second pair of mirrors

[0142] 14 First offset mechanism

[0143] 141 first pivot module

[0144] 142 second pivot module

[0145] 15 Irradiation device

[0146] 16 Physical Light

[0147] 161Two beams of object light reflected by the first pair of mirrors

[0148] 162 Two beams of object light reflected by the second pair of mirrors

[0149] 100 objects to be tested

[0150] 101 Coherent Light Source

[0151] 102 beam expansion device

[0152] 110 Initial Reflector

[0153] 111 First Reflector

[0154] 112 Second Reflector

[0155] 113 Third Reflector

[0156] 114 Fourth Reflector

[0157] 115 beam guide device

[0158] 116 Space Carrier Phase Shifter

[0159] 117 Optical Filter

[0160] 118 focusing mirror

[0161] 119 detector

[0162] 121 First Physical Optics

[0163] 122 Second Physical Light

[0164] 123 Third Light

[0165] 124 Fourth Physical Light

[0166] 131 First Aperture

[0167] 132 Second Aperture

[0168] 133 Third Aperture

[0169] 134 Fourth Aperture

[0170] 310 laser processing unit

[0171] 311 First In-Plane Measuring Device

[0172] 312 Second in-plane measuring device

[0173] 321 Current observation area of ​​the first in-plane measuring device

[0174] 322 Current observation area of ​​the second in-plane measuring device

[0175] 400 virtual four-aperture mask

[0176] 411 first virtual aperture of the first aperture

[0177] 412 Second virtual aperture of the second stop

[0178] 413 The third virtual aperture of the third stop

[0179] 414 Fourth virtual aperture of the fourth stop

[0180] 512 First Spectrum

[0181] 534 Second Spectrum

[0182] 60 incident light

[0183] 800 laser processing unit processing area in the first time frame

[0184] 810 laser processing unit processing area in the second time frame

[0185] 801 The first in-plane measuring device is arranged in the observation area of ​​the first time frame

[0186] 811 The first in-plane measuring device is arranged in the observation area of ​​the second time frame

[0187] 802 The second in-plane measuring device is arranged in the observation area of ​​the first time frame

[0188] 812 The second in-plane measuring device is arranged in the observation area of ​​the second time frame

Claims

1. An in-plane measuring device, characterized in that: The in-plane measuring instrument device comprises: a first pair of reflectors (11), the first pair of reflectors (11) being adapted to reflect object light (16), the object light (16) being light reflected by the object to be measured (100) when the incident light (60) irradiates the object to be measured (100); a first offset mechanism (14), the first offset mechanism (14) being adapted to offset at least one of the first pair of reflectors (11) so that two beams of object light (161) reflected by the first pair of reflectors (11) can form a shear amount along an x-direction on a detector (119) to cause shear interference, wherein the x-direction is an in-plane direction; and A focusing mirror (118) is arranged downstream of the first pair of reflecting mirrors (11) so that two beams of object light (161) reflected by the first pair of reflecting mirrors (11) can be focused onto the detector (119) via the focusing mirror (118).

2. The in-plane measuring device according to claim 1, wherein: The in-plane measurement instrument device includes at least one of the following features: The first pair of reflectors (11) comprises a first reflector (111) for reflecting a first object light (121) in the object light (16) and a second reflector (112) for reflecting a second object light (122) in the object light (16); The in-plane measuring instrument device comprises a beam guiding device (115), wherein the beam guiding device (115) is adapted to guide two beams of object light (161) reflected by the first pair of reflectors (11) toward the focusing mirror (118); The in-plane measuring device comprises a second pair of reflective mirrors (12) and a second offset mechanism, wherein the second offset mechanism is adapted to offset at least one reflective mirror in the second pair of reflective mirrors (12) so that two beams of object light (162) reflected by the second pair of reflective mirrors (12) can form a shear amount along the y direction on a detector (119) to generate shear interference, wherein y is an in-plane direction perpendicular to the x direction, and the second pair of reflective mirrors (12) comprises a third reflective mirror (113) for reflecting a third object light (123) in the object light (16) and a fourth reflective mirror (114) for reflecting a fourth object light (124) in the object light (16); The in-plane measuring instrument device comprises a spatial phase shifting device or a spatial carrier phase shifting device (116) for performing phase reconstruction on the object light (16) reflected by the object to be measured (100); The in-plane measuring instrument device comprises an irradiation device (15), wherein the irradiation device (15) is used to irradiate the object to be measured (100) with incident light (60) along a z direction, where the z direction is an out-of-plane direction perpendicular to the x direction.

3. The in-plane measuring device according to claim 2, wherein: The in-plane measurement instrument device includes at least one of the following features: The first reflector (111) and the second reflector (112) are arranged symmetrically with respect to the incident light (60) in the x-direction; The first offset mechanism (14) comprises a first pivot module (141) adapted to pivot the first reflector (111) around a first pivot axis along the y-direction and / or a second pivot module (142) adapted to pivot the second reflector (112) around a second pivot axis along the y-direction; The third reflector (113) and the fourth reflector (114) are arranged symmetrically with respect to the incident light (60) in the y direction; The second offset mechanism comprises a third pivot module adapted to pivot the third reflector (113) around a third pivot axis along the x-direction and / or a fourth pivot module adapted to pivot the fourth reflector (114) around a fourth pivot axis along the x-direction; The distances between the first reflector (111), the second reflector (112), the third reflector (113) and the fourth reflector (114) and the optical axis of the incident light (60) are equal or different.

4. The in-plane measuring device according to claim 2, wherein: The in-plane measuring instrument device comprises a first polarization device for linearly polarizing a first object light (121) along a first direction, a second polarization device for linearly polarizing a second object light (122) along the first direction, a third polarization device for linearly polarizing a third object light (123) along a second direction, and a fourth polarization device for linearly polarizing a fourth object light (124) along the second direction, wherein the first direction is perpendicular to the second direction.

5. The in-plane measuring device according to claim 2, wherein: The illumination device (15) comprises a coherent light source (101), wherein the coherent light source (101) is a single coherent light source (101) or comprises two coherent light sources (101), and the two coherent light sources (101) are used to emit coherent light of different wavelengths; The coherent light source (101) is a laser; The irradiation device (15) comprises a beam expansion device (102) located downstream of the coherent light source (101), for expanding the light emitted by the coherent light source (101); The irradiation device (15) comprises an initial reflector (110) located downstream of the beam expansion device (102), and the initial reflector (110) is used to reflect the coherent light expanded by the beam expansion device (102) onto the object to be measured (100).

6. The in-plane measuring device according to claim 2, wherein: The in-plane measurement instrument device includes at least one of the following features: The spatial phase shifting device includes at least one of a pixelated phase mask, a spatial light modulator, and a liquid crystal array; The spatial carrier phase shifting device (116) includes at least one of a multi-aperture mask and an adjustable aperture multiplexing device; The spatial carrier phase shifting device (116) comprises a first aperture (131) with adjustable aperture for the first object light (121), a second aperture (132) for the second object light (122), a third aperture (133) for the third object light (123) and / or a fourth aperture (134) for the fourth object light (124).

7. The in-plane measuring device according to claim 6, characterized in that: The in-plane measurement instrument device includes at least one of the following features: The first aperture (131) is arranged upstream of the first reflector (111); The second aperture (132) is arranged upstream of the second reflector (112); The third aperture (133) is arranged upstream of the third reflector (113); The fourth aperture (134) is arranged upstream of the fourth reflector (114).

8. The in-plane measuring device according to claim 2, wherein: The light beam guiding device (115) comprises a right-angle prism having a first reflecting surface for reflecting the first object light (121) reflected by the first reflecting mirror (111) toward the focusing mirror (118), a second reflecting surface for reflecting the second object light (122) reflected by the second reflecting mirror (112) toward the focusing mirror (118), a third reflecting surface for reflecting the third object light (123) reflected by the third reflecting mirror (113) toward the focusing mirror (118), and / or a fourth reflecting surface for reflecting the fourth object light (124) reflected by the fourth reflecting mirror (114) toward the focusing mirror (118).

9. The in-plane measuring device according to claim 2, wherein: The in-plane measuring instrument device includes an analysis and processing device, which is configured to perform Fourier transform on the light intensity data recorded by the detector (119), filter out a first spectrum (512) of interference of conjugate light of the first object light (121) and the second object light (122), and extract first phase difference information between the first object light (121) and the second object light (122) based on the first spectrum (512), and / or filter out a second spectrum (534) of interference of conjugate light of the third object light (123) and the fourth object light (124), and extract second phase difference information between the third object light (123) and the fourth object light (124) based on the second spectrum (534).

10. The in-plane measuring device according to any one of claims 1 to 9, characterized in that: The in-plane measurement instrument device includes at least one of the following features: The in-plane measuring instrument device includes the detector (119); The in-plane measurement device includes an optical filter (117) for filtering stray light; The in-plane measuring instrument device is used to measure in-plane strain, in-plane displacement and / or in-plane stress.

11. The in-plane measuring device according to claim 10, wherein: The in-plane measurement instrument device includes at least one of the following features: The detector (119) is a CCD camera device; The optical filter (117) is arranged upstream of the focusing mirror (118).

12. A laser processing device, characterized in that: The laser processing equipment comprises a laser processing unit (310) and an in-plane measuring instrument device according to any one of claims 1 to 11.

13. The laser processing equipment according to claim 12, characterized in that: The laser processing equipment includes any one of the following features: The in-plane measuring device comprises a first in-plane measuring device (311) located before the laser processing unit (310) along the feeding direction of the laser processing unit (310) and a second in-plane measuring device (312) located after the laser processing unit (310) along the feeding direction of the laser processing unit (310); The laser processing unit (310) is used for laser hardening processing, laser welding processing and / or laser cutting processing; The laser processing equipment includes a controller for adjusting processing parameters of the laser processing unit (310) based on measurement data of the in-plane measuring device.

14. The laser processing equipment according to claim 13, characterized in that The laser processing equipment includes an analysis and processing device. For a processing area on a workpiece, the first in-plane measuring device (311) obtains first measurement data of the processing area before processing, and the second in-plane measuring device (312) obtains second measurement data of the processing area after processing by the laser processing unit (310). The analysis and processing device is configured to derive in-plane strain through correlation calculation of the first measurement data and the second measurement data.

15. The laser processing equipment according to claim 12 or 13, characterized in that: The laser processing apparatus includes an analysis and processing device configured to derive in-plane strain by performing correlation calculations on measurement data of the same in-plane measuring device at different time frames.

Images