Color dot sensor measuring device

Abstract

A color dot sensor measuring device is provided. This improves the visibility of the position of the measuring spot on the observed image. The color dot sensor measuring device includes: a CPS probe for acquiring distance information to the workpiece; a measuring device body for moving the CPS probe; and a computer for calculating workpiece shape information based on the detection signal from the CPS probe. The CPS probe has a chromatic aberration lens that converts the light passing through the aperture into focused light with on-axis chromatic aberration and projects it toward the workpiece. Furthermore, a measuring spot with a wavelength corresponding to the distance is formed on the surface of the workpiece. The reflected light from the measuring spot is then focused onto the aperture by the chromatic aberration lens for detection. Illumination light from an observation light source is irradiated onto the illumination area of ​​the workpiece surface through the chromatic aberration lens, and its reflected light is guided to an observation camera via the chromatic aberration lens. The computer displays a mark indicating the position of the measuring spot on the observed image from the observation camera.

Description

[0001] Related applications

[0002] This application claims priority to Japanese Patent Application No. 2025-049935, filed on March 25, 2025, which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a color point sensor (CPS) measuring device for non-contact measurement of the surface shape of a workpiece. Background Technology

[0004] Generally speaking, depending on how the workpiece is positioned relative to the measuring probe at the start of the measurement, or how the position and posture of the measuring probe are set relative to the workpiece on the worktable, the measurement time can be shortened or lengthened, and the number of probe movements can also be affected. The same applies to microscopic measurements of minute concave and convex shapes. By setting up a camera that acquires an image of the workpiece through an objective lens and displays that image on a display device, the visibility of the measurement area on the workpiece can be improved, facilitating proper workpiece positioning relative to the measuring probe.

[0005] In measurement devices using CPS probes, there are also devices that mount an observation camera on the CPS probe (e.g., Patent Documents 1 and 2). Typically, a confocal optical system is constructed using an aperture and a chromatic aberration lens. The CPS probe converts light from a CPS light source (e.g., light in the wavelength range of 450 nm to 660 nm) into focused light with on-axis chromatic aberration through the confocal optical system and illuminates the workpiece surface. Therefore, a measurement spot is formed on the workpiece surface, consisting of light of wavelengths corresponding to the distance from the probe. The CPS probe is configured such that the reflected light from the measurement spot is again guided to a CPS detector via the confocal optical system. The CPS detector disperses the reflected light from the measurement spot into light of each wavelength and performs photodetection, thereby obtaining distance information from the probe to the workpiece.

[0006] According to Patent Document 1 Figure 4 A dichroic mirror, positioned between the aperture stop and the chromatic aberration lens, converges the illumination light (e.g., 680nm wavelength) from the observation light source onto the optical axis of the CPS probe. The light then passes through the chromatic aberration lens onto the workpiece, illuminating the designated area. The dichroic mirror allows white light (450nm–660nm) from the CPS light source to pass through while reflecting the 680nm illumination light. The reflected light from the illuminated area of ​​the workpiece passes through the chromatic aberration lens to the dichroic mirror, is reflected by the dichroic mirror, and guided to the image sensor to obtain the observed image. The intensity of the 680nm light is used to represent the observed image of the measurement area.

[0007] However, in the optical structure of Patent Document 1, the measuring spot formed on the workpiece is light with a wavelength in the range of 450nm to 660nm, so the reflected light from the measuring spot passes through the dichroic mirror. Therefore, the following problem exists: the measuring spot is formed in the illumination area on the workpiece, but the measuring spot is not reflected in the observation image of the measuring area obtained by the observation camera.

[0008] Next, according to Patent Document 2 Figure 1 A beam splitter positioned between the aperture and the chromatic aberration lens allows a portion of the illumination light (e.g., green light, 531 nm) from the observation light source to pass through, while reflecting the remainder. The reflected illumination light then converges onto the optical axis of the CPS probe and illuminates the workpiece area via the chromatic aberration lens. The reflected light from the illumination area reaches the beam splitter via the chromatic aberration lens, and a portion branches off from the optical axis of the CPS probe and is guided to the observation camera. Furthermore, the beam splitter also allows a portion of the white light from the CPS light source to pass through and reflects the remainder, thus forming a measurement spot on the workpiece based on a specified wavelength within the wavelength range (450 nm to 660 nm) of the white light from the CPS light source.

[0009] When observing using such a beam splitter, a portion of the reflected light from the measurement spot on the workpiece is also guided to the observation camera, thus projecting the measurement spot into the observation image. However, due to the characteristics of the CPS probe, not only the wavelength of light focused on the workpiece surface (the light forming the measurement spot) enters the observation camera, but other wavelengths of light that are not focused on the workpiece surface also enter the observation camera via the beam splitter, resulting in the measurement spot appearing unclear (blurred image) in the observation image.

[0010] Therefore, in Patent Document 2, the configuration is as follows: a narrowband filter is set in front of the camera, selecting only the wavelength (531 nm) of the reflected light used for imaging and guiding it to the camera. However, in order for the observation camera to acquire an observation image of the measurement area including the measurement spot, the focal plane of the camera must be adjusted so that the wavelength (531 nm) of the narrowband filter matches the height of the formed measurement spot.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 2018-66670

[0014] Patent Document 2: Japanese Patent Application Publication No. 2023-20888 Summary of the Invention

[0015] Solution for solving the problem

[0016] One aspect of the color dot sensor (CPS) measuring apparatus includes: a color dot sensor (CPS) probe that optically acquires distance information of a workpiece; a measuring apparatus body that moves the CPS probe, mounted on a probe mount, relative to the workpiece; and a computer that processes detection signals from the CPS probe and calculates workpiece shape information, wherein...

[0017] The CPS probe includes: an aperture that allows light from a CPS light source to pass through; and a chromatic aberration optical element that converts the light passing through the aperture into focused light with on-axis chromatic aberration and emits it toward the workpiece. The CPS probe is configured to form a measurement spot of wavelength corresponding to the distance to the workpiece on the surface of the workpiece within the range of on-axis chromatic aberration of the focused light.

[0018] Furthermore, the CPS probe is configured to focus the reflected light from the measurement spot onto an aperture via the chromatic aberration optical element and then guide it to the CPS detector, thereby causing the CPS detector to output a detection signal.

[0019] The CPS probe is further configured to: direct illumination light from the observation light source onto the illumination area of ​​the workpiece surface through the chromatic aberration optical element, and guide the reflected light from the illumination area to the observation camera via the chromatic aberration optical element.

[0020] The computer functions as a marker display unit, which displays markers on the position of the measured light spot in the observation image acquired by the observation camera. Attached Figure Description

[0021] Figure 1 This is a diagram showing an example of the structure of a CPS probe.

[0022] Figure 2 This is a diagram showing an example of the structure of a CPS measuring device.

[0023] Figure 3 (A)~(E) are illustrations of the method for determining the position of the marker.

[0024] Figure 4 (F)~(H) are illustrations of the method for determining the marker position.

[0025] Figure 5 Figures (A) to (D) are explanatory diagrams of the evaluation method for measuring the positional offset of the light spot from the marker.

[0026] Figure 6(A) to (C) are explanatory diagrams of the correction method for the positional offset of the mark caused by the misalignment of the optical axis of the CPS probe and the observation camera.

[0027] Figure 7 This is a diagram showing another structural example of a CPS probe. Detailed Implementation

[0028] The embodiments of the color dot sensor (CPS) measuring device according to this application will now be described with reference to the accompanying drawings. Each embodiment is merely shown as an example or aspect, and the numerical values, functional range, application scenarios, etc., are not limited by such examples. Furthermore, the embodiments can be appropriately combined within a range where the structural effects do not contradict each other.

[0029] (First Implementation)

[0030] Figure 1 A schematic example of the structure of the CPS probe 10 is shown. The CPS probe 10 is detachable from the probe head of the CPS measuring device and is used to optically acquire distance information of a point on the workpiece on the worktable of the CPS measuring device. The CPS probe 10 has a probe body 12, a light source and detection unit 14, and an optical fiber 16 connecting the two.

[0031] First, the light source and detection unit 14 will be described. The light source and detection unit 14 includes a CPS light source 18, a CPS detector 20, and a signal processing circuit 22. A white LED emitting white light W is provided in the CPS light source 18. The white light W includes a continuous wavelength region from the blue wavelength region to the red wavelength region, for example, visible light from 500nm to 700nm, but the specific wavelength region is not limited. Alternatively, a mercury lamp or the like can be used instead of an LED.

[0032] The fiber optic section 16 comprises multiple optical fibers (a-c), such as fiber (a) connected to the probe body 12, fiber (b) connected to the CPS light source 18, and fiber (c) connected to the CPS detector 20. These optical fibers (a-c) are connected to an optical fiber splitter (d). White light W from the CPS light source 18 is guided to the probe body 12 by the fiber optic section 16. Additionally, measurement light M from the probe body 12 is guided to the CPS detector 20 by the fiber optic section 16. Alternatively, an optical fiber coupler or the like can be used instead of the optical fiber splitter (d).

[0033] The probe body 12 has a pen-shaped housing 24 with its long side as the optical axis A, and a chromatic aberration lens 26 disposed within the housing 24. At the front end of the housing 24 is an illumination port for irradiating white light W from the chromatic aberration lens 26 toward the workpiece. At the rear end of the housing 24 (the end on the probe mount side), there is a connection port for an optical fiber (a), from which white light W is radiated into the interior of the housing 24. In this document, this connection port is referred to as the aperture stop (AP).

[0034] The chromatic aberration lens 26 is an example of the chromatic aberration optical element of the present invention, and is a lens or lens group designed for use in a color sensor. The chromatic aberration lens 26 converts the white light W emitted from the aperture AP into focused light with on-axis chromatic aberration and illuminates the workpiece from the illumination port. The chromatic aberration lens 26 has the characteristic of focusing the white light W incident on the probe body 12 at a focusing position P on the optical axis A corresponding to the wavelength λ. In this document, light in a state where the focusing positions P corresponding to the wavelength λ are continuously distributed on the optical axis A is referred to as focused light with on-axis chromatic aberration. Figure 1 The diagram schematically illustrates the state in which white light W, containing wavelengths λ1 to λ6, is focused at different focal positions P1 to P6 corresponding to each wavelength. In the case of white light being visible light in the range of 500 nm to 700 nm, according to the positive dispersion of the chromatic aberration lens 26, Figure 1 The focal position P1 shown is the focal position of visible light with the shortest wavelength λ1 (e.g., green light), and the focal position P6 is the focal position of visible light with the longest wavelength λ6 (e.g., red light).

[0035] Furthermore, L1 to L6 represent the distances from the probe body 12 to the focusing positions P1 to P6. The range from the minimum value (distance L1) to the maximum value (distance L6) of this distance is the measurement range of the CPS probe 10.

[0036] Figure 1 The diagram illustrates the state in which the workpiece is positioned within the measurement range of the CPS probe 10. For example, when the workpiece surface coincides with the focal position P2, the chromatic aberration lens 26 forms a measurement spot formed by light of wavelength λ2 focused on the workpiece surface at focal position P2. The light reflected from this measurement spot (reflected light of wavelength λ2) is refocused onto the aperture AP by the chromatic aberration lens 26. The confocal optical system consisting of the aperture AP and the chromatic aberration lens 26 guides the light of wavelength λ2 in the white light W, reflected from the workpiece surface at focal position P2, to the optical fiber (a). A portion of the white light W, excluding wavelength λ2, also enters the aperture AP through the chromatic aberration lens 26, but since it is not focused on the workpiece surface, the amount of light is small. Therefore, the light of wavelength λ2 focused on the workpiece surface is the strongest among the light entering the aperture AP.

[0037] This principle holds regardless of where the surface of the workpiece is located within the measurement range. For example, when the workpiece surface is at the focus position P3, the measurement spot is formed by light with wavelength λ3, so its reflected light is focused again at the position of the diaphragm AP. The light entering the diaphragm AP is guided as measurement light M to the CPS detector. In this way, the focus positions P1, P2, ... within the measurement range on the optical axis A correspond one-to-one to the wavelengths λ1, λ2, ... of the measurement light M. In other words, the distances L1, L2, ... from the CPS probe 10 to the workpiece correspond one-to-one to the wavelengths λ1, λ2, ... of the measurement light M.

[0038] The CPS detector 20 is a photodetector with a spectroscopic function. It uses a light dispersion element such as a diffraction grating to disperse the received measurement light M, and uses a linear array detector to perform detection. The light dispersion element guides the measurement light M in a direction corresponding to its wavelength. The traveling direction of light from the light dispersion element varies depending on the wavelength, and multiple detection elements of the linear array detector are arranged to cover all these directions. Therefore, based on the position of the detection element with the maximum light intensity signal, the wavelength λ of the maximum-intensity light contained in the measurement light M can be determined.

[0039] The signal processing circuit 22 determines the wavelength λ of the maximum-intensity light based on the light intensity signal from the CPS detector 20, that is, the distance L from the irradiation port of the probe body 12 to the workpiece surface, and outputs it to a computer as distance information. In addition, the signal processing circuit 22 outputs the light intensity signal of each detection element to the computer according to requirements from the computer.

[0040] Furthermore, as the chromatic aberration optical element, a diffractive optical element (DOE) can also be used instead of the aforementioned chromatic aberration lens 26. The diffraction phenomenon in a DOE is caused by the fine structure formed on the surface of the optical element, which can shorten the optical path length compared with lenses and the like. According to the negative dispersion characteristic of the condensing DOE, the distribution of focus positions is Figure 1 opposite. That is, Figure 1 the focus position P1 of is the focus position of visible light with the longest wavelength λ6, and the focus position P6 is the focus position of visible light with the shortest wavelength λ1.

[0041] <Structure of CPS Measuring Apparatus>

[0042] Figure 2 A structural example of the CPS measuring apparatus 100 is schematically shown. The CPS measuring apparatus 100 includes the aforementioned CPS probe 10, a measuring apparatus main body 30, and a computer 40 connected thereto. The measuring apparatus main body 30 includes a probe moving device 32 for moving the CPS probe 10 relative to a workpiece, and a worktable 34 for placing the workpiece.

[0043] The probe moving device 32 moves the CPS probe 10, mounted on the probe holder 36, relative to the workpiece in the XYZ axis directions. It is configured, for example, by a Y-direction slider, an X-direction slider, and a Z-direction slider. The computer 40 performs drive control of these sliders using its functions. Furthermore, position detection sensors are provided in each direction of movement to detect the position information of each slider. Therefore, the probe moving device 32 can output this position information as the position information of the CPS probe 10 to the computer 40. However, the probe moving device 32 is not limited to the above structure. For example, it can also be configured to move the worktable 34 in the Y-axis direction.

[0044] The computer 40 can calculate the workpiece shape information based on the position information of the CPS probe 10 and the distance information from the CPS probe 10 to the workpiece. The computer 40 is an information processing device connected to the CPS probe 10 and the measuring device body 30 via wired or wireless means, and may be constructed by combining multiple information processing devices. In addition, the computer 40 includes a monitor 42 for displaying the observed images.

[0045] <Structure of the optical system for observation>

[0046] Return to Figure 1 This explains the structure of the observation unit 50 of the CPS probe 10.

[0047] The probe body 12 also includes a dichroic mirror 28, an observation unit 50, and a connecting portion 62 for detachably connecting the observation unit 50 to the probe body 12, all housed within the housing 24. The dichroic mirror 28 is positioned on the optical axis A between the chromatic aberration lens 26 and the aperture AP. The dichroic mirror 28 is wavelength selective, allowing light in the 500nm to 700nm wavelength range to pass through while reflecting light in the wavelength range below 500nm.

[0048] The observation unit 50 includes an observation light source 52, a semi-transparent mirror 54, an observation camera 56, a camera mirror 58, and a housing 60 that houses them. The observation unit 50 is configured as a single unit and can be processed as a whole.

[0049] The optical axis B of the observation unit 50 is approximately orthogonal to the optical axis A of the white light W of the probe body 12 at the position of the dichroic mirror 28. A semi-transparent mirror 54 and a camera mirror 58 are arranged on the optical axis B of the observation unit 50. The optical axis of the observation light source 52 is approximately orthogonal to the optical axis B of the observation unit 50 at the position of the semi-transparent mirror 54. The optical axis of the observation camera 56 is approximately orthogonal to the optical axis B of the observation unit 50 at the position of the camera mirror 58.

[0050] The observation light source 52 can be, for example, an LED that emits illumination light N (violet light) with a wavelength of approximately 430 nm. The wavelength of the illumination light N is not limited, but in this embodiment, it is preferable to use any wavelength not included in the wavelength range (500 nm to 700 nm) of white light W. For example, a single wavelength of red light biased towards the longer wavelength side can also be used. Illumination light N in the infrared region can also be used, not limited to visible light. Furthermore, other solid-state light sources, lamps, etc., can also be used as the observation light source 52.

[0051] The observation camera 56 is, for example, a camera composed of multiple pixels arranged in a plane, such as an image sensor, and can use a CMOS area sensor or a CCD area sensor. The observation camera 56 only needs to be able to detect light in the wavelength region of the illumination light N and output the light intensity signal of each pixel.

[0052] The structure of the observation optical system within the observation unit 50 is not limited to the structure described above. It can include additional optical elements such as lenses, or it can have an optical system of arbitrary design.

[0053] Furthermore, the connecting portion 62 may, for example, consist of a locking hole and a locking groove formed near the opening on the probe body 12 side, and a locking protrusion formed near the opening on the observation unit 50 side. During connection, the two are fitted together, and the observation unit 50 is fixed to the probe body 12 by screws or the like. This structure of the connecting portion 62 is merely one example; other structures may also be used. Moreover, the connecting portion 62 preferably includes a mechanism capable of finely adjusting the optical axis B of the observation unit 50 relative to the optical axis A of the probe body 12 (e.g., the fine-tuning mechanism using screws or the like described above).

[0054] Approximately 50% of the illumination light N from the observation light source 52 is reflected in a roughly orthogonal direction at the semi-transparent mirror 54 and enters the dichroic mirror 28 through the opening of the connecting part 62. The dichroic mirror 28 selectively transmits white light W (500nm~700nm) from the aperture AP, but reflects the illumination light N (430nm) from the observation unit 50, and aligns its direction of travel with the optical axis A of the white light W.

[0055] The chromatic aberration lens 26 converts white light W into focused light representing on-axis chromatic aberration and illuminates the workpiece. Additionally, the chromatic aberration lens 26 converges the illumination light N and illuminates a designated area (illumination area) on the workpiece. Furthermore, the chromatic aberration lens 26 converges the reflected light from the measurement spot on the workpiece surface and the reflected light from the illumination area, and directs it onto the dichroic mirror 28. The dichroic mirror 28 allows the reflected light from the measurement spot (light in the wavelength range of 500nm to 700nm) to pass through and return to the aperture AP. Additionally, the dichroic mirror 28 reflects the reflected light (430nm) from the illumination area and returns it to the observation unit 50. The reflected light returning to the observation unit 50, as the observation light K, is incident along the optical axis B onto the semi-transparent mirror 54. Then, approximately 50% of the observation light K that passes through the semi-transparent mirror 54 is reflected by the camera mirror 58 and incident on the observation camera 56.

[0056] <Monitor for observing images>

[0057] The computer is configured to drive and control the CPS light source 18 and the observation light source 52, outputting control signals including the emission intensity and timing of each light source 18 and 52 to drive them. Additionally, the computer receives output signals from the observation camera 56, generates observation images of the measurement areas on the workpiece, and displays them on an external monitor or similar device. The observation image is based on the intensity of a single-wavelength (430nm) observation light K and is coaxial with the optical axis A of the CPS probe 10.

[0058] <Marker Display Program>

[0059] Figure 2 The computer 40 functions as a marker display unit. The marker display program executed by the computer 40 is a program that simultaneously displays geometric graphic images (markers) on the observed image at positions corresponding to the measured light spots. Specifically, it is a program that causes the computer 40 to perform marker position determination, marker display, and offset confirmation functions. These programs are stored in storage devices or the like constituting the computer 40. The computer 40 can automatically execute these programs as CPS measurements are performed, or it can selectively execute these programs based on user settings for the measurement conditions.

[0060] <Method for determining marker position>

[0061] To utilize Figure 3 The procedure for determining the marking positions on the calibration plate, as shown in the top view of (A), is explained. In this calibration plate, a calibration plate (pattern) of geometric shape is formed on a glass substrate using a metal film (e.g., a chromium film). Figure 3As shown in the enlarged view of (B), the calibration plate has boundary lines between the glass and metal film parallel to the Y direction, boundary lines between the glass and metal film parallel to the X direction, and the intersection of these boundary lines. The calibration plate is used because a computer can easily identify the location (on the XY plane) of the intersection of the two boundary lines by performing image processing on the observed image. Furthermore, it is because the coordinate information of any two points on each boundary line can be easily obtained through CPS measurement.

[0062] First, for the calibration plate placed on the workbench 34, two points (p1, p2) on the boundary line in the Y direction and two points (p3, p4) on the boundary line in the X direction are set as the scanning measurement objects.

[0063] Next, a scanning measurement is performed using a CPS probe. During the scanning measurement, the CPS probe is moved relative to each point in a direction perpendicular to the boundary line while continuously performing CPS measurements using the measurement spot. Alternatively, multiple scanning measurements can be performed on the same point, and the average can be calculated to obtain the coordinate information of that point.

[0064] Figure 3 (C) is a longitudinal section view of the calibration plate at point p1. Due to the different reflectivities of the glass surface and the metal film surface, the signal intensity of the CPS detector varies when CPS measurements are performed on each surface. Therefore, as... Figure 3 As shown in Figure (C), the coordinates of point p1 can be calculated based on the changes in the signal intensity of the CPS detector during scanning. The coordinates of other points p2, p3, and p4 can also be obtained in this way.

[0065] Next, calculations are performed based on the coordinate information of the four points (p1~p4). Figure 3 The coordinate information of the intersection point p of the two boundary lines shown in (D). For example, as... Figure 3 As shown in (E), the parameters of the line passing through points p1 and p2 are calculated, and the parameters of the line passing through points p3 and p4 are calculated. Using these parameters, the coordinate information (Xp, Yp) of the intersection point p is calculated. In this way, the computer functions as the position recognition unit of the intersection point p.

[0066] Next, using the calculated coordinate information (Xp, Yp), the CPS probe is moved to the intersection point p of the calibration plate. Accompanying this, as... Figure 4 As shown in (F), the measurement spot of the CPS probe moves to the intersection point p. Furthermore, Figure 3 (A), (B), (D) and Figure 4The top view of the calibration plate (F) illustrates the state of the calibration plate placed on the worktable as directly observed by the user from the front. The measurement spot formed on the calibration plate cannot be as... Figure 4 It is not as clearly visually recognizable as (F), but cannot be seen or is blurry.

[0067] In this state, the observation light source and observation camera are activated to acquire observation images of the calibration plate. Figure 4 (G) shows the observed image displayed on the monitor. The intersection point p of the calibration plate enters the field of view (i.e., the illuminated area) of the observed image, but sometimes... Figure 4 The field of view (G) is displayed offset to the upper left from the center of the field of view. Additionally, sometimes the longitudinal and lateral directions of a rectangular field of view do not align with the X and Y directions of the calibration plate, causing the field of view to be displayed at an angle. In such cases, it is preferable, for example, for the user to adjust the mounting posture of the observation unit to... Figure 4 To make the intersection point p coincide with the center of the field of view, or to eliminate the tilt of the field of view, as in (H).

[0068] Finally, by performing image processing on the observed image, the position of the pixel corresponding to the intersection point p of the calibration plate on the observed image is determined, and the mark is displayed on the determined pixel. The mark can be a geometric graphic image such as a circle, ring, or cross. In this way, the computer functions as the mark display unit.

[0069] The above actions, in addition to user settings and adjustments, are achieved through the execution of a marker position determination program. By executing this marker position determination action, the markers can be correctly displayed at the position of the measurement spot on the observed image.

[0070] According to the CPS measuring apparatus of this embodiment, the user can easily confirm the position of the measuring spot on the observed image by displaying the markings. In particular, regardless of the distance from the CPS probe to the workpiece in the CPS measurement, the user can easily confirm the measurement position in the CPS measurement by displaying the markings on the observed image.

[0071] Furthermore, the marking position can be determined similarly using patterned components with a certain pattern, not limited to calibration plates. Alternatively, the marking position can be determined similarly using a workpiece with a certain shape that can define a point, such as a protrusion or a recess. The position of such a point needs to be identifiable by image processing of the observed image and by the detection signal measured by CPS. For example, a point is preferably formed in a way that combines patterns with different reflectivities such as brightness and darkness to determine its position, and more preferably formed in a way that combines patterns with height differences to determine its position. In the example of the calibration plate described above, the function of identifying the position of the intersection point p of two boundary lines was explained, but the coordinate information of the protrusion formed on the workpiece can also be directly obtained by scanning and measuring it with a CPS probe.

[0072] In addition, when acquiring the coordinate information of a point such as the intersection point p of the calibration plate, in cases where there is a height difference such as between the glass surface and the metal film surface, edge detection can be performed by using the change in the wavelength of light detected by the CPS detector (that is, the change in the detected distance information) instead of edge detection using the change in the signal intensity of the CPS detector.

[0073] <Offset Confirmation Method>

[0074] Next, the procedure for confirming the offset between the position of the measured light spot and the position of the marker will be explained. This procedure, for example, can be used to verify whether the determined position of the marker matches the actual position of the measured light spot. Here, using... Figure 3 The same calibration plate is used, but the intersection point p is not mandatory; any patterned component or workpiece with at least one boundary line on its surface is acceptable. Such a boundary line needs to be identifiable through image processing of the observed image and based on the detection signal measured by CPS.

[0075] First, the boundary line in the Y direction of the calibration plate is set as the object to be scanned and measured.

[0076] Next, while acquiring the observation images, a scanning measurement using the CPS probe is performed. During this scanning measurement, such as... Figure 5 As shown in (A), CPS measurements using the measurement spot are performed continuously while the CPS probe is moved in a direction perpendicular to the boundary line in the Y direction.

[0077] exist Figure 5 The longitudinal section diagram (B) shows the positional relationship between the calibration plate and the CPS probe.

[0078] Figure 5 (C) is a graph of the signal strength of the CPS detector based on CPS measurements. Figure 5(D) is a graph of the brightness values ​​detected by the camera and the pixels corresponding to the marked positions on the observed image.

[0079] Here, if the timing of determining the position of the boundary line using CPS coincides with the timing of the change in brightness value (light received) of the pixel at the position corresponding to the mark display location by the observation camera, then the offset can be considered zero. However, if there is a timing difference, the measured position of the light spot will deviate from the position of the mark. In other words, the offset can be easily and accurately determined based on the difference between the timing of determining the position of the boundary line using CPS and the timing of the change in light received at the pixel at the position corresponding to the mark display location by the observation camera. In this way, the computer functions as an offset verification unit. If the offset exceeds the reference, the position of the mark display is redefined.

[0080] In such Figure 5 As shown in (C), the X-coordinate of the boundary line for the change in signal strength based on the CPS detector is x1, as... Figure 5 As shown in (D), when the X coordinate of the boundary line of the change in brightness value of the pixel corresponding to the marked display position based on the observation camera is x2, the difference between each measured position (|x1-x2|) becomes the offset.

[0081] Furthermore, in cases where there is a height difference between the glass surface and the metal film surface, such as the boundary line of a calibration plate, edge detection can be performed using the change in the wavelength of light detected by the CPS detector (i.e., the change in the detected distance information) instead of edge detection using the change in the signal intensity of the CPS detector.

[0082] In the first embodiment described above, a marker is displayed at the position of the measurement spot on the observation image. Therefore, regardless of the distance from the workpiece to the CPS probe during CPS measurement, the user can easily confirm the position of the measurement spot on the observation image. Furthermore, the marker position only needs to be determined once, and the marker remains fixed at a single point on the observation image regardless of the movement of the CPS probe.

[0083] Furthermore, in the first embodiment, light with a wavelength (less than 500 nm) not included in the wavelength region (500 nm to 700 nm) of the white light W used for CPS measurement is used as the observation light K, thus allowing the use of a dichroic mirror as the light splitting element. Compared to a beam splitter, the advantage of a dichroic mirror is that it can suppress the loss of light quantity in both the measurement light M and the observation light K.

[0084] Furthermore, the advantage of a dichroic mirror is that even when a workpiece is illuminated with, for example, 430nm illumination light N, the reflected light will not pass through the dichroic mirror, thus not affecting the distance information detected by the CPS probe, enabling observation during CPS measurement. For example, by simultaneously driving the CPS light source and the observation light source, the user can simultaneously view the workpiece image on a monitor while setting CPS measurement conditions and executing the measurement program. Additionally, the user can monitor the measurement status of the CPS measurement device operating according to the part program in real time via the monitor image.

[0085] Furthermore, the timing of each light irradiation can be appropriately controlled, not limited to simultaneous irradiation of white light W and illumination light N. For example, after irradiating the illumination light N and observing the illuminated area, white light W can be used instead of illumination light N to perform CPS measurement on the workpiece.

[0086] On the other hand, if the conditions regarding light loss can be met, a beam splitter (e.g., a semi-transparent mirror) can also be used as the light splitting element in the first embodiment. In this case, for example, even if a 430nm illumination light N is irradiated onto the workpiece and a portion of its reflected light passes through the beam splitter and is detected by the CPS detector, the 430nm wavelength will have almost no effect on the distance information detected by the CPS detector because it is outside the measurement range (500nm~700nm) of the CPS probe. Furthermore, although the measurement spot is not clear in the observed image, it can be displayed at its position as a marker.

[0087] (Second Implementation)

[0088] <Correction method for marking positions in optical axis misalignment>

[0089] In the second embodiment, such as Figure 6 As shown in (A), the operation of the procedure for automatically correcting the mark position when the optical axis of the observation light K is misaligned relative to the optical axis A of the CPS probe 10 will be explained. Only the function of the computer differs from the CPS measuring apparatus of the first embodiment; the other structures are the same.

[0090] exist Figure 6 (B) shows, with magnification, the positional relationship between the position of the measurement spot formed on the workpiece surface at the upper, center, and lower limits of the measurement range of the CPS probe 10 in the case of optical axis misalignment and the display position of the mark based on the determination method of the first embodiment.

[0091] At the center of the measurement range, the optical axis A is aligned with the optical axis of the observation light K, therefore there is no offset between the position of the measurement spot and the position of the marked display. However, at the upper and lower limits of the measurement range, due to the misalignment of the optical axis A and the optical axis of the observation light K, an offset occurs between the position of the measurement spot and the position of the marked display.

[0092] Therefore, in this embodiment, the computer first sets multiple distances from the CPS probe 10 to the intersection point p of the calibration plate within the measurement range (on-axis chromatic aberration) of the CPS probe 10. Furthermore, the computer's position recognition and mark display functions determine, according to the determination method of the first embodiment, the display position of the mark on the observed image based on the position of the intersection point p for each of the set distances. Moreover, the correspondence between the distance from the CPS probe 10 to the workpiece and the display position of the mark is stored in a table form in a storage unit or the like.

[0093] The computer's marking display function reads the mark display position from a stored correspondence table based on the distance information to the workpiece being measured, acquired by the CPS probe 10 during CPS measurement. Then, the mark is displayed at the read position on the observed image. This corrects the mark display position in case of optical axis misalignment. Figure 6 The magnified view of (C) shows that the position of the corrected mark is consistent with the position of the measured spot.

[0094] (Third Implementation)

[0095] Next, the structure of the CPS measuring apparatus according to the third embodiment will be described. In this embodiment, the apparatus used... Figure 7 The CPS probe 110 is shown. The CPS probe 110 uses a beam splitter 128 as an optical splitting element.

[0096] Similar to the first embodiment, violet light, for example, at 430 nm, is used as the illumination light. Furthermore, the wavelength range for the measurement is set to 500 nm to 700 nm. Additionally, descriptions of structures identical to those in the first embodiment are omitted.

[0097] On the other hand, apart from the beam splitter 128, the difference from the first embodiment is that the CPS light source 118 can output light in the wavelength range (500nm~700nm) used for the measurement range, as well as light in the wavelength range less than 500nm. For example, the CPS light source 118 can output white light W in the range of 430nm~700nm. In addition, a narrowband filter 120 is arranged near the observation camera 56 (for example, allowing only light in the wavelength range less than 500nm to pass through).

[0098] <Method for determining marker position>

[0099] For example, the 430nm wavelength light included in the white light W from the CPS light source 118 can form a measurement spot at a position deviating from the measurement range (a position closer to the probe body than the minimum measurement range). Therefore, if the workpiece surface is arranged at this position, part of the reflected light of the 430nm measurement spot formed on the workpiece surface is reflected by the beam splitter 128 and travels into the observation unit 50, and enters the observation camera 56 through the narrow-band filter 120. Therefore, the 430nm measurement spot is reflected in the observation image acquired by the observation camera 56, so it is preferable to display a mark at this position.

[0100] In addition, the illumination light from the observation light source also has a wavelength of 430nm. Part of the reflected light from the illumination area of the workpiece passes through the beam splitter 128 and reaches the CPS detector 20. However, since the wavelength of 430nm deviates from the wavelength range of the measurement range of the CPS probe 110, it does not affect the output of the CPS measurement.

[0101] (Other Embodiments)

[0102] The present disclosure is not limited to the embodiments described above, and various other embodiments can be implemented.

[0103] <The wavelength region of the CPS light source may also be the same as that of the observation light source>

[0104] In the above description, the wavelength region of the white light W for CPS measurement is different from the wavelength region of the illumination light N for observation, but the present invention is not limited thereto. For example, light having the same wavelength region as the white light W for CPS measurement may also be used as the illumination light N. For example, in Figure 1 the structure of the CPS probe, when the wavelength region of the CPS light source is 500nm to 700nm, a white LED with the same wavelength region of 500nm to 700nm can also be used as the observation light source. For the light splitting element, a beam splitter is used instead of a dichroic mirror. Thereby, a color observation image of the workpiece can be generated based on the output of the observation camera. In addition, in the color observation image, although not clear, the measurement spot is reflected, so a mark can be displayed at its position.

[0105] In addition, it may also be configured such that when part of the illumination light N transmits through the beam splitter and affects the CPS measurement, the computer controls the light emission timing of each light source so that the light emission timings of the white light from the CPS light source and the observation light source do not overlap.

[0106]

[0107] Furthermore, in the above description, the aperture of the CPS probe is used as an opening for illuminating white light W towards the chromatic aberration lens, and also as a focal point for reflected light from the measurement spot, but it is not limited to this. For example, it can also be configured such that a branching element (beam splitter, etc.) is provided within the CPS probe to guide the reflected light from the workpiece from the optical axis A of the white light W toward the optical axis of the CPS detector, so that it is focused on an aperture different from the aperture illuminating the white light W.

[0108] The following notes are also disclosed regarding implementations that include the above embodiments.

[0109] (Appendix 1) A CPS measuring device comprises: a color dot sensor probe, i.e., a CPS probe, which optically acquires distance information of a workpiece; a measuring device body that moves the CPS probe, which is mounted on a probe holder, relative to the workpiece; and a computer that processes the detection signals from the CPS probe and calculates workpiece shape information. The CPS measuring device is characterized in that...

[0110] The CPS probe includes: an aperture that allows light from a CPS light source to pass through; and a chromatic aberration optical element that converts the light passing through the aperture into focused light with on-axis chromatic aberration and emits it toward the workpiece. The CPS probe is configured to form a measurement spot of wavelength corresponding to the distance to the workpiece on the surface of the workpiece within the range of on-axis chromatic aberration of the focused light.

[0111] Furthermore, the CPS probe is configured to focus the reflected light from the measurement spot onto an aperture via the chromatic aberration optical element and then guide it to the CPS detector, thereby causing the CPS detector to output a detection signal.

[0112] The CPS probe is further configured to: direct illumination light from the observation light source onto the illumination area of ​​the workpiece surface through the chromatic aberration optical element, and guide the reflected light from the illumination area to the observation camera via the chromatic aberration optical element.

[0113] The computer functions as a marker display unit, which displays markers on the position of the measured light spot in the observation image acquired by the observation camera.

[0114] (Note 2) The CPS measuring device according to the first invention is characterized in that,

[0115] This includes a workpiece having a point on its surface, the position of which is configured to be recognizable in the observed image and also based on the detection signal of the CPS detector.

[0116] The computer also functions as a position recognition unit, which identifies the position of a point on the surface by moving the measuring light spot along the workpiece. This is based on changes in light intensity or wavelength detected by the CPS detector.

[0117] The marker display unit moves the CPS probe to the position of the point identified by the position recognition unit, acquires an observation image of the point through the observation camera, and displays the marker at the position of the point obtained by image recognition from the observation image.

[0118] (Appendix 3) The CPS measuring device according to the second invention is characterized in that,

[0119] The workpiece having a point on its surface is a patterned component with a pattern expressed by light and shadow or height difference, and the position of the point is determined by the pattern.

[0120] (Appendix 4) The CPS measuring apparatus according to any one of the first to third inventions is characterized in that,

[0121] This includes workpieces with boundary lines on their surfaces, the boundary lines being formed in a way that allows for image recognition in the observed image and also for recognition based on the detection signal of the CPS detector.

[0122] The computer also functions as an offset confirmation unit to confirm the offset between the position of the measured light spot and the display position of the mark.

[0123] The offset confirmation unit identifies the position of the boundary line by moving the measuring spot across the workpiece with a boundary line on its surface, based on changes in light intensity or wavelength detected by the CPS detector, and acquires an observation image of the boundary line using the observation camera.

[0124] The offset confirmation unit confirms the offset based on the difference between the timing of identifying the position of the boundary line and the timing of the change in light received at the pixel of the observation camera located at the position corresponding to the display position of the mark.

[0125] (Appendix 5) The CPS measuring apparatus according to any one of the second to fourth inventions is characterized in that,

[0126] The computer sets multiple distances to the workpiece having a point on its surface within the range of chromatic aberration on the axis.

[0127] For each set distance to the workpiece, the location identification unit and the mark display unit determine the display position of the mark based on the position of a point, and save the correspondence between the distance to the workpiece and the display position of the mark.

[0128] Furthermore, when the distance information to the workpiece being measured is determined by the CPS probe, the mark display unit reads the display position of the mark corresponding to the distance information according to the correspondence, and displays the mark at the read display position.

[0129] (Appendix 6) The CPS measuring apparatus according to any one of the first to fifth inventions is characterized in that,

[0130] The wavelength range of the light emitted by the observation light source is different from the wavelength range of the light emitted by the CPS light source.

[0131] (Appendix 7) The CPS measuring apparatus according to any one of the first to sixth inventions is characterized in that,

[0132] A light-splitting element, consisting of a dichroic mirror or a beam splitter, is disposed between the aperture and the chromatic aberration optical element.

[0133] Illumination light from the observation light source is combined with light from the CPS light source by the light splitting element, and reflected light from the illumination area is guided toward the observation camera by the light splitting element.

[0134] Explanation of reference numerals in the attached figures

[0135] 10 CPS probe

[0136] 12. Probe body

[0137] 14. Light source and detection unit

[0138] 16. Fiber Optic Department

[0139] 18 CPS light source

[0140] 20 CPS detectors

[0141] 22 Signal Processing Circuit

[0142] 24. Shell

[0143] 26 Chromatic aberration lenses

[0144] 28 dichroic mirrors

[0145] 30. Main body of the measuring device

[0146] 32 Probe Moving Device

[0147] 34 workbenches

[0148] 40 Computers

[0149] 42 monitors

[0150] 50 Observation Units

[0151] 52. Light source for observation

[0152] 54 Semi-transparent and semi-reflective mirror

[0153] 56. Observation camera

[0154] 58. Camera reflector

[0155] 60 Housing

[0156] 62 Connecting part

[0157] 100 CPS measuring device

[0158] 110 CPS probe

[0159] 118 CPS light source

[0160] 120 Narrowband Filter

[0161] 128 beam splitter

[0162] AP aperture

[0163] M Measurement light

[0164] N illumination light

[0165] K Observing light

[0166] W White light

Claims

1. A color dot sensor measuring device, comprising: a color dot sensor probe, i.e., a CPS probe, which optically acquires distance information of a workpiece; a measuring device body that moves the CPS probe, which is mounted on a probe holder, relative to the workpiece; and a computer that processes the detection signals from the CPS probe and calculates the shape information of the workpiece, characterized in that... The CPS probe includes: an aperture that allows light from a CPS light source to pass through; and a chromatic aberration optical element that converts the light passing through the aperture into focused light with on-axis chromatic aberration and emits it toward the workpiece. The CPS probe is configured to form a measurement spot of wavelength corresponding to the distance to the workpiece on the surface of the workpiece within the range of on-axis chromatic aberration of the focused light. Furthermore, the CPS probe is configured to focus the reflected light from the measurement spot onto an aperture via the chromatic aberration optical element and then guide it to the CPS detector, thereby causing the CPS detector to output a detection signal. The CPS probe is further configured to: direct illumination light from the observation light source onto the illumination area of ​​the workpiece surface through the chromatic aberration optical element, and guide the reflected light from the illumination area to the observation camera via the chromatic aberration optical element. The computer functions as a marker display unit, which displays markers on the position of the measured light spot in the observation image acquired by the observation camera.

2. The color dot sensor measuring device according to claim 1, characterized in that, This includes a workpiece having a point on its surface, the position of which is configured to be recognizable in the observed image and also based on the detection signal of the CPS detector. The computer also functions as a position recognition unit, which identifies the position of a point on the surface by moving the measuring light spot along the workpiece. This is based on changes in light intensity or wavelength detected by the CPS detector. The marker display unit moves the CPS probe to the position of the point identified by the position recognition unit, acquires an observation image of the point through the observation camera, and displays the marker at the position of the point obtained by image recognition from the observation image.

3. The color dot sensor measuring device according to claim 2, characterized in that, The workpiece having a point on its surface is a patterned component with a pattern expressed by light and shadow or height difference, and the position of the point is determined by the pattern.

4. The color dot sensor measuring device according to claim 1, characterized in that, This includes workpieces with boundary lines on their surfaces, the boundary lines being formed in a way that allows for image recognition in the observed image and also for recognition based on the detection signal of the CPS detector. The computer also functions as an offset confirmation unit to confirm the offset between the position of the measured light spot and the display position of the mark. The offset confirmation unit identifies the position of the boundary line by moving the measuring spot across the workpiece with a boundary line on its surface, based on changes in light intensity or wavelength detected by the CPS detector, and acquires an observation image of the boundary line using the observation camera. The offset confirmation unit confirms the offset based on the difference between the timing of identifying the position of the boundary line and the timing of the change in light received at the pixel of the observation camera located at the position corresponding to the display position of the mark.

5. The color dot sensor measuring device according to claim 2, characterized in that, The computer sets multiple distances to the workpiece having a point on its surface within the range of chromatic aberration on the axis. The location identification unit and the mark display unit determine the display position of the mark based on the position of a point for each set distance to the workpiece, and save the correspondence between the distance to the workpiece and the display position of the mark. Furthermore, when the distance information to the workpiece being measured is determined by the CPS probe, the mark display unit reads the display position of the mark corresponding to the distance information according to the correspondence, and displays the mark at the read display position.

6. The color dot sensor measuring device according to any one of claims 1 to 5, characterized in that, The wavelength range of the light emitted by the observation light source is different from the wavelength range of the light emitted by the CPS light source.

7. The color dot sensor measuring device according to any one of claims 1 to 5, characterized in that, A light-splitting element, consisting of a dichroic mirror or a beam splitter, is disposed between the aperture and the chromatic aberration optical element. Illumination light from the observation light source is combined with light from the CPS light source by the light splitting element, and reflected light from the illumination area is guided toward the observation camera by the light splitting element.

Images