WO2016021359A1 - Shape measurement device, coating apparatus, and shape measurement method - Google Patents

Abstract

An objective lens (20) splits white light from an epi-illumination light source (12) into two light beams, irradiates one light beam onto the surface of a transparent film (3), irradiates the other light beam onto a reference mirror (24), and obtains interference light from the reflected light from both surfaces. After positioning the objective lens (20) above the transparent film (3), a control computer (40) photographs a plurality of images of the interference light while moving the transparent film (3) and objective lens (20) relative to each other vertically. The control computer (40) carries out a first processing step in which within the photography period of a CCD camera (30), image numbers are assigned to the plurality of photographed images in the order that the images were photographed, and for each of the pixels composing the images, a plurality of image numbers at which the brightness of the pixel peaks are determined, and a second processing step in which after the plurality of images are photographed, the film thickness or uneven portion height of the transparent film (3) is detected on the basis of the image numbers at which the plurality of brightnesses peak.

Description

Shape measuring device, coating device, and shape measuring method

The present invention relates to a shape measuring device, a coating device, and a shape measuring method, and more particularly to a technique for measuring the film thickness of a transparent film or the height of an uneven portion formed on the surface of the transparent film.

Pattern processing technology using an application needle with a tip diameter of several tens of μm and laser light with a spot diameter of several μm to several tens of μm is combined with precision positioning technology on the order of micrometers, so even a fine pattern can be positioned at a predetermined position. Can be processed accurately. For this reason, conventionally, it has been used for flat panel display correction work, solar cell scribing work, and the like (for example, Japanese Patent Application Laid-Open No. 2007-268354 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2009-122259 (Patent Document)). 2), see Japanese Patent Application Laid-Open No. 2009-237086 (Patent Document 3)). In particular, the processing technique using an application needle can be applied to a paste having a high viscosity, which is not good for a dispenser, and has recently been used to form a film having a thickness of 10 μm or more as compared with a flat panel display. For example, it is used to form electronic circuit patterns and printed circuit board wiring of semiconductor devices such as MEMS (Micro Electro Mechanical Systems) and sensors. Patterns produced by printed electronics technology, which is a promising manufacturing technology in the future, are also classified as thick films, and are expected to be used in the future.

JP 2007-268354 A JP 2009-122259 A JP 2009-237086 A JP 2008-286630 A

In ink application using an application needle, it is important to determine the quality of the location where the ink is applied. For example, Patent Document 3 discloses a defect correction method for correcting defects in a color filter constituting a liquid crystal display by ink application. In Patent Document 3, images of regions including defects before and after the correction process are taken, the brightness of the images before and after the correction process is compared, and an abnormality in the correction process is detected based on the comparison result.

The above-mentioned Patent Document 3 employs a method in which an ink application target is a color filter, and an ink of the same color as that of a pixel having a white defect is applied to a white defect that has lost color in the color filter. Since the color filter is composed of three colors of R (red), G (green), and B (blue), the ink of the same color as the pixel has high contrast. Therefore, it is relatively easy to detect a change in the image before and after ink application.

However, the ink targeted by the application needle is not only high in contrast as in the case of the color filter described above. For example, some adhesives and bio-related samples have low contrast, and it is difficult to detect changes in the image before and after ink application even in a visible light microscope image. With such an ink, it is not possible to employ a determination method based on image comparison before and after ink application as described in Patent Document 3 above.

Here, there is a method for detecting the three-dimensional shape of an object as a method other than the image comparison described above and effective for an object having a low contrast and a particularly transparent object. Among them, as a detection method using a white interferometer, for example, Japanese Patent Application Laid-Open No. 2008-286630 (Patent Document 4) describes interference light caused by reflected light on the surface of a transparent film and interference light caused by reflected light on the back surface of the transparent film. A method is disclosed in which the thickness of the transparent film is detected based on the distance between the peaks and the refractive index of the transparent film after observation and obtaining the peak of the interference light intensity for each interference light.

In the above-mentioned Patent Document 4, a discriminant analysis method used mainly for determining a binarization threshold in image processing is used to obtain two peaks of interference light intensity. This discriminant analysis method uses the property that the variance between classes is maximum between two peaks when the luminance histogram of the image shows bimodality, and each luminance is set as a threshold value with the luminance that maximizes the variance between classes. The peak is to be calculated.

More specifically, in Patent Document 4, the absolute value of the difference between the interference light intensity and the average value thereof is set as the frequency in the histogram, and the imaging position where each interference light intensity is obtained is set as the luminance. The imaging position that maximizes the interclass variance is determined as the imaging position that separates the two peaks. Then, with the obtained imaging position as the center, the peak on one side is used as the peak of the intensity of the interference light from the back surface of the transparent film, and the peak on the other side is the interference light from the light reflected from the surface of the transparent film. The intensity peak.

However, the technique described in Patent Document 4 has the following problems. First, the discriminant analysis method is effective for data showing bimodality, but has a problem that it is difficult to deal with data having three or more peaks. Therefore, when the transparent film is formed by laminating two or more transparent films, three or more peaks of interference light intensity may occur. Depending on the discriminant analysis method, these three or more interference light intensity levels may occur. It is difficult to detect the peak.

Second, the calculation for obtaining the variance between classes requires many steps, but the calculation needs to be performed pixel by pixel, which requires a lot of processing time. Further, when the arithmetic processing is realized by an electronic circuit in order to shorten the processing time, the cost of the apparatus is increased.

The present invention has been made to solve such a problem, and the object thereof is to form the thickness of each transparent film and the unevenness formed on the surface of each transparent film in an object formed from at least one transparent film. It is to provide a shape measuring device, a coating device, and a shape measuring method capable of measuring the height of a part with a simple and inexpensive device configuration.

The shape measuring apparatus according to the present invention measures the film thickness of the transparent film or the height of the uneven portion formed on the surface of the transparent film. The transparent film is formed by laminating a single layer or a plurality of transparent films. The shape measuring device divides the white light emitted from the illuminating device into two luminous fluxes, irradiates one on the surface of the transparent film and the other on the reference surface. An objective lens for interfering with the reflected light from the lens to obtain interference light, an observation optical system for observing the interference light obtained via the objective lens, and an imaging device for photographing the interference light via the observation optical system Including a head unit, a positioning device for positioning the head unit at a desired position above the surface of the transparent film by moving the head unit and the transparent film relative to each other, and controlling the positioning device and the image pickup device After positioning the objective lens above the film, a plurality of images of interference light are taken while continuously changing the vertical distance from the transparent film to the objective lens, and the transparent film is based on the taken images. Film thickness Others and a shape detection unit that detects a height of the uneven portion. The shape detection unit attaches an image number to a plurality of captured images in the order in which they are captured within the imaging cycle of the imaging device, and sets a plurality of image numbers at which the luminance reaches a peak for each of a plurality of pixels constituting the image. Based on the first-stage processing to be obtained and the image number obtained by the first-stage processing after the imaging device has captured a plurality of images, the film thickness of the transparent film or A second-stage process for detecting the height of the uneven portion is executed.

The coating apparatus according to the present invention includes a coating mechanism that forms a transparent film formed by laminating a single layer or a plurality of transparent films by coating a transparent liquid material on a main surface of a substrate, and illumination that outputs white light. The device and the white light emitted from the illumination device are separated into two luminous fluxes, one of which is irradiated on the surface of the transparent film and the other is irradiated on the reference surface, and the reflected light from both surfaces is interfered to obtain interference light An objective lens, an observation optical system for observing interference light obtained through the objective lens, a head unit including an imaging device for photographing the interference light through the observation optical system, a head unit and a coating unit After positioning the objective lens above the coating unit by controlling the positioning device and the imaging device by positioning the head unit at a desired position above the surface of the coating unit by relatively moving Application part Shape detection that captures multiple images of interference light while continuously changing the vertical distance to the objective lens, and detects the film thickness of the transparent film or the height of the concave and convex portions based on the captured multiple images A part. The shape detection unit attaches an image number to a plurality of captured images in the order in which they are captured within the imaging cycle of the imaging device, and sets a plurality of image numbers at which the luminance reaches a peak for each of a plurality of pixels constituting the image. Based on the first-stage processing to be obtained and the image number obtained by the first-stage processing after the imaging device has captured a plurality of images, the film thickness of the coating portion or A second-stage process for detecting the height of the uneven portion is executed.

The shape measuring method according to the present invention is a shape measuring method for measuring a film thickness of a transparent film formed by laminating a single layer or a plurality of transparent films or a height of an uneven portion formed on the surface of the transparent film. The white light emitted from the lighting device and the white light emitted from the lighting device are separated into two light beams, one of which is irradiated on the surface of the transparent film and the other is irradiated on the reference surface, and the reflected light from both surfaces An objective lens for obtaining interference light, an observation optical system for observing the interference light obtained through the objective lens, and an imaging device for photographing the interference light through the observation optical system. And moving the relative position with respect to the transparent film to position the head portion at a desired position above the surface of the transparent film, and after positioning the objective lens above the transparent film, the upper and lower sides from the transparent film to the objective lens Continuously changing the direction distance Is not an image of the interference light multiple shots while, and a step of detecting the height of the film thickness or uneven portions of the transparent film on the basis of a plurality of images taken. The step of detecting the film thickness of the transparent film or the height of the concavo-convex portion includes assigning an image number to a plurality of photographed images in the order of photographing within a photographing period of the imaging device, and a plurality of pixels constituting the image. For each, a first stage process for obtaining a plurality of image numbers at which the luminance reaches a peak, and a plurality of luminances obtained by the first stage process after the imaging device has photographed a plurality of images have a peak. Based on the image number, a second stage process of detecting the film thickness of the transparent film or the height of the concavo-convex portion is executed.

According to the present invention, the thickness of each transparent film and the height of the concavo-convex part formed on the surface of each transparent film in an object formed from at least one transparent film are measured with a simple and inexpensive apparatus configuration. be able to.

1 is an overall configuration diagram of a shape measuring apparatus according to an embodiment of the present invention. It is the figure which expanded the part of the objective lens shown in FIG. It is a figure which shows the change of the intensity | strength of interference light when the position of an objective lens is changed. It is a functional block diagram for demonstrating the control structure of the shape measuring apparatus according to this Embodiment. It is a flowchart which concerns on the shape measuring method according to this Embodiment. This is a summary of definitions of various variables used in peak detection processing. Is a diagram showing a relationship between luminance values _f i (x, y) and the image number i of a pixel on the image _{f i} (x, y). It is a flowchart which shows the detailed procedure of the process of step S30 of FIG. It is a figure explaining the peak search process in the process of step S05 of FIG. It is a figure explaining the peak determination process in the process of step S09 of FIG. It is a figure explaining the valley search process in the process of step S12 of FIG. It is a figure explaining the valley decision process in the process of step S13 of FIG. It is a figure explaining the search process of the 2nd peak. It is a figure explaining contrast value M _i #. It is a figure for demonstrating the calculation method of the film thickness of each transparent film. It is a figure explaining the coherence distance in interference light. It is a perspective view which shows the whole structure of the coating device according to this Embodiment. It is a perspective view which shows the principal part of an observation optical system and an ink application | coating mechanism. It is the figure which looked at the principal part from the A direction of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent part in a figure, and the description is not repeated.

[Configuration of shape measuring device]
FIG. 1 is an overall configuration diagram of a shape measuring apparatus according to an embodiment of the present invention. Referring to FIG. 1, the shape measuring apparatus according to the present embodiment measures the film thickness of transparent film 3 provided on the main surface of substrate 5 that is an object. The shape measuring device further measures the height of the uneven portion formed on the surface of the transparent film 3.

The transparent film 3 is formed by laminating a single layer or two or more transparent films. When the transparent film 3 is composed of a plurality of transparent films, each transparent film constituting the transparent film 3 may be composed of different materials. As an example, the transparent film 3 includes three transparent films 3a to 3c. In the configuration diagram of FIG. 1, a two-dimensional plane forming the main surface of the substrate 5 is defined by the X axis and the Y axis, and the thickness direction of the substrate 5 is defined by the Z axis.

The shape measuring device includes an incident light source 12 (illumination device), a filter 14, a condenser lens 16, a half mirror 18, an objective lens 20, an imaging lens 28, and a CCD (Coupled Charged Device) camera 30 (imaging device). And a control computer 40 that controls the operation of the entire apparatus. The head unit 10 is mounted on a Z stage (not shown). The Z stage moves the head unit 10 in a direction perpendicular to the substrate 5 (Z-axis direction).

The incident light source 12 is a high-luminance white light source such as a white LED (Light Emitting Diode). When a white light source is used as the epi-illumination light source 12, the interference light intensity is maximized only at the focal position of the objective lens 20, unlike the case of using a single wavelength light source such as a laser. Therefore, it is suitable for measuring the shape of the object.

A filter 14 is provided at the exit of the incident light source 12. When the light emitted from the epi-illumination light source 12 passes through the filter 14, white light having a center wavelength λ ₀ (nm) is obtained. In addition, when white LED is used for the incident light source 12, the filter 14 is configured by a low-pass filter that selectively transmits light on the long wavelength side of two peaks of the emission spectrum of the white LED. preferable. Details of the filter 14 will be described later.

The objective lens 20 is a two-beam interference objective lens. The two-beam interference objective lens separates the white light emitted from the light source into two light beams and irradiates one on the surface of the object, and irradiates the other on the reference surface, thereby reflecting light from the surface of the object. And the reflected light from the reference surface. In the present embodiment, by using a two-beam interference objective lens as the objective lens 20, the interference light intensity at the focal position can be maximized.

The objective lens 20 is composed of, for example, a Mirau-type interference objective lens. The Mirau interference objective lens includes a lens 22, a reference mirror 24, and a beam splitter 26. The objective lens 20 may be a Michelson type or a linique type interference objective lens.

The light that has passed through the filter 14 is collected by the condenser lens 16 and then reflected by the half mirror 18 toward the lens 22. The light incident on the lens 22 is divided into light that passes in the direction of the transparent film 3 by the beam splitter 26 and light that reflects in the direction of the reference mirror 24. The light reflected by the surface of the transparent film 3 and the light reflected by the surface of the reference mirror 24 are merged again by the beam splitter 26 and condensed by the lens 22. Thereafter, the light emitted from the lens 22 passes through the half mirror 18 and then enters the imaging surface 30 a of the CCD camera 30 through the imaging lens 28.

The control computer 40 outputs a drive signal to the Z stage to move the head unit 10 and the transparent film 3 relative to each other in the vertical direction (Z-axis direction), thereby moving the head unit 10 over the surface of the transparent film 3. It is positioned at a predetermined upper position. After positioning the head unit 10, the control computer 40 further moves the objective lens 20 in the optical axis direction (Z-axis direction) by driving the Z stage and moving the head unit 10 in the Z-axis direction. Thereby, the distance L2 in the Z-axis direction from the surface of the transparent film 3 to the beam splitter 26 changes. An optical path between the reflected light from the surface of the transparent film 3 and the reflected light from the reference mirror 24 according to the difference between this distance L2 and the distance L1 in the Z-axis direction from the beam splitter 26 to the reference mirror 24. A length difference occurs. The reflected light from the surface of the transparent film 3 and the reflected light from the reference mirror 24 interfere with each other according to the optical path length difference, thereby generating interference light.

The control computer 40 continuously changes the distance L2 in the Z-axis direction from the surface of the transparent film 3 to the objective lens 20 (beam splitter 26), while the CCD camera 30 generates interference light generated by the optical path length difference. Take multiple images.

The half mirror 18 and the imaging lens 28 constitute an observation optical system for observing the interference light obtained through the objective lens 20. The interference light observed by the observation optical system is converted into an image signal (electric signal) by the CCD camera 30. The intensity of the interference light, that is, the brightness is maximized when the optical path lengths of the reflected light from the transparent film 3 and the reflected light from the reference mirror 24 are equal. At this time, the objective lens 20 is focused on the surface of the transparent film 3.

Here, when white light is incident on the single-layer transparent film through the two-beam objective lens, the white light is reflected on the surface of the transparent film and the back surface of the transparent film (boundary surface between the transparent film and the substrate). . FIG. 2 is an enlarged view of a portion of the objective lens 20 shown in FIG. FIG. 2A shows a state in which interference light is formed by the reflected light from the surface of the transparent film and the reflected light from the reference mirror 24. FIG. 2B shows a state in which interference light is formed by reflected light from the back surface of the transparent film and reflected light from the reference mirror 24.

Referring to FIG. 2A, when the optical path lengths of the reflected light from the surface of the transparent film and the reflected light from the reference mirror 24 are equal, the intensity of the interference light by the reflected light from the surface of the transparent film is maximum. Become. On the other hand, referring to FIG. 2B, when the optical path lengths of the reflected light from the back surface of the transparent film and the reflected light from the reference mirror 24 are equal, the intensity of the interference light by the reflected light from the back surface of the transparent film is Maximum.

2B, the optical path length of the reflected light is longer by 2 nt than FIG. 2A, where n is the refractive index of the transparent film and t is the film thickness.

FIG. 3 is a diagram showing a change in the intensity of the interference light when the position Z of the objective lens 20 is changed. In the figure, the horizontal axis indicates the position Z of the objective lens 20, and the vertical axis indicates the intensity of the interference light.

Referring to FIG. 3, two peaks appear in the intensity of the interference light. One peak appears due to the maximum intensity of the interference light due to the reflected light from the back surface of the transparent film. The other peak appears due to the maximum intensity of the interference light due to the reflected light from the surface of the transparent film. If the difference between the position Z of the objective lens 20 when one peak appears and the position Z of the objective lens 20 when the other peak appears is a distance D, the distance D depends on the film thickness t of the transparent film. It becomes the value. Specifically, when the refractive index of the transparent film is n, the film thickness t of the transparent film can be expressed by D / (2n).

As shown in FIG. 1, in the present embodiment, the transparent film 3 is formed by laminating two or more transparent films. Therefore, when the distance L2 from the surface of the transparent film 3 to the beam splitter 26 is changed, at least three peaks appear in the intensity of the interference light. Therefore, when a plurality of images captured by the CCD camera 30 are captured, the control computer 40 detects three or more peaks that appear in the intensity of the interference light based on the captured plurality of images. Then, the control computer 40 detects the film thickness of each transparent film based on the distance L2 corresponding to each of the detected three or more peaks and the refractive index of each transparent film. Further, the control computer 40 detects the height of the uneven portion formed on the surface of each transparent film.

[Transparent film shape measurement method]
Below, the shape measuring method of the transparent film performed by the shape measuring apparatus according to the present embodiment will be described. The shape measurement of the transparent film according to the present embodiment is performed by, for example, performing an ink application mechanism (not shown) on the main surface of the substrate 5 by applying a transparent ink over a plurality of layers, and then performing an ink application unit. It is performed in the process of measuring the shape of

FIG. 4 is a functional block diagram for illustrating the control configuration of the shape measuring apparatus according to the present embodiment. Referring to FIG. 4, the control configuration of the shape measuring device includes a CCD camera 30, a capturing device 42, a processing device 44, and a driving device 45. The CCD camera 30 is mounted on the head unit 10. The capture device 42, the processing device 44, and the drive device 45 are provided inside the control computer 40.

The driving device 45 moves the Z stage on which the head unit 10 is mounted to the search start position. If the current position of the Z stage is Z _p and the search range that is the range for moving the Z stage is Δ, for example, the Z stage is moved to the initial position (Z _p −Δ / 2). Here, the minus direction of the Z stage is a direction approaching the substrate 5, and the plus direction is a direction away from the substrate 5. The search is performed in the plus direction from the initial position (Z _p −Δ / 2), that is, in the direction in which the Z stage moves away from the substrate 5. Therefore, a range of Δ is searched in the positive direction from the initial position (Z _p −Δ / 2). Note that the search direction is not necessarily a direction away from the substrate 5, and may be a direction approaching the substrate 5.

The CCD camera 30 images the interference light observed by the observation optical system 25 including the half mirror 18 and the imaging lens 28 (FIG. 1). When the Z stage starts to move and enters a constant speed state, the capture device 42 starts sampling an image taken by the CCD camera 30. The Z stage moves at a predetermined speed v (μm / second). The moving speed v (μm / second) of the Z stage is determined as follows. Assuming that the center wavelength of white light is λ (μm) and the frequency of the vertical synchronization signal of the CCD camera 30 is F (Hz), the moving speed v (μm / second) is an image sampling period 1 / F (second). In the meantime, the Z stage is determined to move by λ / 8 (μm). This moving speed v corresponds to π / 2 in the phase increment of white light and satisfies the Nyquist principle. By changing the phase by π / 2, the peak of the interference light intensity can be easily detected.

The capture device 42 samples an image at a constant cycle (preferably a cycle of a vertical synchronization signal of the CCD camera 30). Specifically, the capturing device 42 starts sampling of an image using a vertical synchronization signal of the CCD camera 30 as a trigger. Then, when the sampling of the image is completed, the capture device 42 immediately transfers the sampled image to the processing device 44. At this time, the capture device 42 directly transfers the image to the storage unit 46 of the processing device 44. For example, DMA (Direct Memory Access) transfer is used for this image transfer. The sampling and transfer of the image by the capturing device 42 are repeatedly executed at an image sampling period 1 / F (second).

The processing device 44 includes a storage unit 46 and a central processing unit 48. The storage unit 46, the image _{f i} is transferred from the capture device 42 at a sampling period of the image 1 / F (s). The sampled images are given image numbers in the order in which they were taken. Image f _i represents the image recorded on the i-th. The image number i takes a value of i = 1, 2,... N (N is an integer of 3 or more). That is, a total of N images f ₁ to f _N are transferred to the storage unit 46.

The storage unit 46 sequentially stores the images f _i transferred from the capture device 42. The central processing unit 48 immediately after the image f _i in the storage unit 46 is transferred, a process for detecting the peak of the interference light intensity is the processing of the first stage. The central processing unit 48, by the method described below, for each of a plurality of pixels constituting an image f _i, detects the image number when the luminance value reaches its peak.

When the first stage processing is completed, the central processing unit 48 determines the film thickness of each transparent film based on three or more image numbers respectively corresponding to three or more peaks detected for each pixel. A second step of detecting the height of the concavo-convex portion in each transparent film is executed. In this second stage process, whether or not the ink applied on the main surface of the substrate 5 has a desired film thickness by comparing the detected film thickness of the transparent film with a predetermined threshold value. Can be determined.

Further, the total value of the thicknesses of the transparent films calculated for each pixel can be regarded as the volume of the ink applied on the main surface of the substrate 5. Therefore, by comparing the total value of the transparent film thickness for each pixel with a predetermined threshold value, it can be determined whether or not the ink application amount is a desired application amount.

FIG. 5 is a flowchart according to the shape measuring method according to the present embodiment. The flowchart shown in FIG. 5 can be realized by executing a program stored in advance in the control computer 40.

Referring to FIG. 5, capture device 42 samples an image at an image sampling period 1 / F (seconds) (step S10). Capture device 42, the sampling of the image _{f i} of the image number i is completed, directly transfers the image _{f i} sampled in the storage unit 46 of the processor 44 (step S20). Storage unit 46 stores sequentially the image f _i transferred.

The central processing unit 48 of the processor 44, the image f _i is transferred to the storage unit 46, as the first stage of the process (peak detecting process), for each pixel constituting the image f _i, brightness value and peak The image number is detected (step S30). The central processing unit 48 completes this peak detection process immediately before the next (i + 1) -th image f _{i + 1} is transferred. That is, the first stage processing is executed during the image sampling period 1 / F (second). The central processing unit 48 stores in the storage unit 46 the image number detected for each pixel and having the peak luminance value (step S40).

Next, the central processing unit 48 determines whether or not sampling of all images within the search range has been completed (step S50). When the sampling of the _Nth image fN is not completed (NO in step S50), it is determined that the sampling of the image within the search range is not completed, and the process is returned to the beginning.

On the other hand, when the sampling of the _Nth image fN is completed (YES in step S50), the central processing unit 48 determines that the sampling of all the images within the search range is completed, and performs the second stage processing (shape) Detection process). The central processing unit 48 detects the film thickness of each transparent film or the height of the concavo-convex part in each transparent film, based on the image number stored in the storage unit 46 at which the luminance value for each pixel peaks (step). S60).

(Peak detection processing)
Hereinafter, the procedure of the peak detection process (step S30 in FIG. 5) which is the first stage process will be described in detail. In the peak detection process, as described above, the luminance value for each pixel constituting the image f _i detects image number reaches a peak.

FIG. 6 summarizes definitions of various variables used in the peak detection process. Referring to FIG. 6, the pixels constituting the i-th image f _i, identified using coordinates (x, y). f _i (x, y) represents the luminance value of one pixel on the i-th image _{f i} (x, y).

Figure 7 is a diagram showing a relationship between luminance values _f i (x, y) and the image number i of a pixel on the image _{f i} (x, y). In the figure, the horizontal axis indicates the image number i (1 ≦ i ≦ N), and the vertical axis indicates the luminance value f _i (x, y) of the pixel (x, y). The filled in circles, actually obtained in the sampling of the image f _i luminance values f _{i (x,} y) shows. On the other hand, the solid line in the figure represents the change in interference light intensity at the position of the pixel (x, y) within the search range.

Referring to FIG. 7, the interference light intensity shows a peak in the vicinity of a specific image number. Accordingly, the luminance value f _i (x, y) in the vicinity of the specific image number also shows a peak. The position of the Z stage corresponding to the peak point of the interference light intensity is the focal position of the pixel (x, y). The central processing unit 48 detects the image number corresponding to the peak of the interference light intensity at the position of the pixel (x, y) based on the relationship between the luminance value f _i (x, y) and the image number i.

FIG. 8 is a flowchart showing a detailed procedure of the process (peak detection process) in step S30 of FIG. Referring to FIG. 8, when the central processing unit 48 acquires the k-th (1 <k <N) image f _k , the central processing unit 48 starts peak detection processing using a total of k images.

The central processing unit 48 initially acquires the i-th image _{f i} (step S01), using a k images including images _{f i,} the pixel (x, y) mean a luminance value (hereinafter , Referred to as “brightness average value”) (step S02). Specifically, the luminance average value a is calculated by the following equation (1) using a total of k images from the (i−k + 1) th image f _{i−k + 1} to the i th image f _i. .

Next, the central processing unit 48 calculates a relative value (hereinafter referred to as “luminance relative value”) of the luminance value f _i (x, y) of each pixel using the calculated luminance average value a. Specifically, the pixels on the image _{f i} (x, y) of the luminance relative value _d i (x, y) of When the luminance relative value _d i (x, y) are shown in the following equation (2) Thus, this corresponds to the deviation of the luminance value f _i (x, y) from the luminance average value a.

Next, the central processing unit 48 compares the luminance relative value of each pixel of the image _{f i d i (x, y} ) and, with a predetermined threshold value _{T f.} The central processing unit 48 selects a pixel (x, y) having a luminance relative value d _i (x, y) equal to or greater than the threshold T _f , and a pixel candidate (hereinafter, referred to as a peak of the luminance value f _i (x, y)). (Referred to as “candidate pixel”). In this way, the central processing unit 48, the candidate pixel from among a plurality of pixels constituting the image f _i (x, y) to extract (step S03).

Next, the central processing unit 48 detects the peak of the luminance value for the extracted candidate pixel (x, y). The central processing unit 48 first sets a flag F (x, y) indicating the detection state of the peak of the candidate pixel (x, y). As shown in FIG. 6, the flag F (x, y) is set to a value “0” when the peak of the luminance value is not detected. On the other hand, when searching for the peak of the luminance value, the flag F (x, y) is set to the value “1”. Further, when searching for a “valley” formed between two adjacent peaks, the flag F (x, y) is set to a value “2”. The central processing unit 48 detects the peak of the luminance value of the candidate pixel (x, y) while referring to the flag F (x, y).

Specifically, the central processing unit 48 first determines whether or not the flag F (x, y) = 0 (step S04). When flag F (x, y) = 0 (YES in step S04), central processing unit 48 executes a process of searching for a peak in the luminance value (peak search process) (step S05).

In the peak search process, a plurality of image numbers corresponding to a plurality of peaks appearing in the luminance value f _i (x, y) are detected in ascending order of the image number based on the luminance relative value d _i (x, y). In the following description, in one pixel (x, y), the number of detected peaks is c (x, y), the image number of the latest peak candidate is p _max (x, y), and the latest peak candidate. _Is assumed to be d _max (x, y). The latest valley candidate image number is p _min (x, y), the latest valley candidate intensity (relative luminance value) is d _min (x, y), and the latest peak image number is n (x , Y). All of these values are initialized to the value “0” in the initial state before the search is started.

In this embodiment, as an example, the upper limit value N _p = 4 of the peak number c (x, y) is set. The image numbers of the detected peaks are stored in n _j (x, y) in the order of detection (1 ≦ j ≦ N _p ). In the initial state, the values of the peak image numbers n ₁ (x, y) to n _Np (x, y) are all initialized to “−1”.

The storage unit 46 has a storage area in which storage cells are two-dimensionally arranged so as to have the same resolution as that of the CCD camera 30. Each memory cell stores F, c, p _max , p _min , d _max , d _min , n, n _j of the corresponding pixel (x, y). That is, the storage unit 46 stores a total of eight two-dimensional arrays of F, c, p _max , p _min , d _max , d _min , n, and n _j .

FIG. 9 is a diagram for explaining the peak search process in the process of step S05 of FIG. FIG. 9 shows a process of searching for the first peak. The black circles in the figure indicate the actually acquired luminance value f _i (x, y), and the solid line indicates the transition of the luminance value f _i (x, y). On the other hand, the broken line in the figure shows the transition of the luminance value f _i (x, y) predicted from the next image f _{i + 1} onward. The peak number c (x, y) = 0 (initial value) is set.

Referring to FIG. 9, central processing unit 48 calculates difference Δi between image number n (x, y) of the latest peak and image number i. This difference Δi corresponds to the number of images from the latest peak image number n (x, y) to image number i. Since n (x, y) = 0 (initial value) during the search for the first peak, the number of images Δi = i. The central processing unit 48 compares the number of images Δi with the threshold value _Td . During the search for the first peak, the threshold _Td is set to a value equal to the number of images Δi. Thus, the relationship of Δi ≧ _Td is always established during the search for the first peak.

The central processing unit 48 compares the relative luminance value d _i (x, y) of the pixel (x, y) with the intensity d _max (x, y) of the latest peak candidate. When the relative luminance value d _i (x, y) is larger than d _max (x, y), the central processing unit 48 updates the value of d _max (x, y) to the relative luminance value d _i (x, y). (D _max (x, y) = d _i (x, y)). Furthermore, the central processing unit 48 updates the image number p _max (x, y) of the latest peak candidate to i (p _max (x, y) = i) (step S06). The central processing unit 48 sets the latest peak image number n (x, y) to i. On the other hand, when the luminance relative value d _i (x, y) is equal to or less than d _max (x, y), the central processing unit 48 does not update d _max (x, y) and p _max (x, y).

The central processing unit 48 further sets the flag F (x, y) to the value “1” (step S07). After setting the flag F (x, y), the process is returned to the beginning.

Returning to FIG. 8, when the flag F (x, y) is not 0 (NO in step S04), the central processing unit 48 subsequently determines whether or not the flag F (x, y) = 1 ( Step S08). When flag F (x, y) = 1 (YES in step S08), central processing unit 48 executes processing for determining the peak of the luminance value (peak determination processing) (step S09).

FIG. 10 is a diagram for explaining the peak determination process in the process of step S09 of FIG. FIG. 10 shows a process of determining the first peak. As in FIG. 9, the black circles in the figure indicate the actually acquired luminance values f _i (x, y), and the solid line indicates the transition of the luminance values f _i (x, y). On the other hand, the broken line in the figure shows the transition of the luminance value f _i (x, y) predicted from the next image f _{i + 1} onward. The peak number c (x, y) = 0 (initial value) is set.

Referring to FIG. 10, central processing unit 48 calculates difference Δw between image number p _max (x, y) of the latest peak candidate and image number i. This difference Δw corresponds to the number of images from the image number p _max (x, y) of the latest peak candidate to the image number i. The central processing unit 48 compares the threshold value T _w a predetermined image number [Delta] w. If the image number Δw is greater than the threshold value _{T w,} the central processing unit _{48, p} max _(x, y) were determined in the image number of the peaks, the most recent peak image number n (x, y) of the _{p max} (x , Y). The central processing unit 48 counts up (adds 1) the number of peaks c (x, y) (step S10).

The central processing unit 48 further sets the flag F (x, y) to the value “2” (step S11). After setting the flag F (x, y), the process is returned to the beginning. On the other hand, if the number of images Δw is equal to or less than the threshold value T _w is maintained flag F (x, y) = 1, the process is first returned.

Returning to FIG. 8, when the flag F (x, y) is not 1 (NO in step S08), that is, when the flag F (x, y) = 2, the central processing unit 48 determines the peak of the luminance value. A process of searching for a valley between the peaks (valley search process) is executed (step S12).

FIG. 11 is a diagram for explaining a valley search process in the process of step S12 of FIG. FIG. 11 shows a process of searching for a valley between the first peak and the second peak. The black circles in the figure indicate the actually acquired luminance value f _i (x, y), and the solid line indicates the transition of the luminance value f _i (x, y). On the other hand, the broken line in the figure shows the transition of the luminance value f _i (x, y) predicted from the next image f _{i + 1} onward.

Referring to FIG. 11, the central processing unit 48 compares the luminance relative value d _i (x, y) of the pixel (x, y) with the intensity d _min (x, y) of the latest valley candidate. When the luminance relative value d _i (x, y) is smaller than d _min (x, y), the central processing unit 48 updates the value of d _min (x, y) to the luminance relative value d _i (x, y). (D _min (x, y) = d _i (x, y)). The central processing unit 48 further updates the image number p _min (x, y) of the latest valley candidate to i (p _min (x, y) = i).

On the other hand, when the luminance relative value d _i (x, y) is equal to or greater than d _min (x, y), the central processing unit 48 executes a process of determining the valley of the luminance value (valley determination process) ( Step S13). FIG. 12 is a diagram for explaining the valley determination process in the process of step S13 of FIG. FIG. 12 shows a process of determining a valley between the first peak and the second peak. The black circles in the figure indicate the actually acquired luminance value f _i (x, y), and the solid line indicates the transition of the luminance value f _i (x, y). On the other hand, the broken line in the figure shows the transition of the luminance value f _i (x, y) predicted from the next image f _{i + 1} onward.

Referring to FIG. 12, central processing unit 48 calculates difference Δw between image number p _min (x, y) of the latest valley candidate and image number i. This difference Δw corresponds to the number of images from the latest valley candidate image number p _min (x, y) to image number i. The central processing unit 48 compares the number of images Δw and the threshold T _w. If the image number Δw is larger than the threshold value _{T w,} the central processing unit 48 _will determine _p min (x, y) to the image number of the valley.

Next, the central processing unit 48 initializes the value of the strength d _max (x, y) of the latest peak candidate to “0” in order to shift to the search processing for the second peak (step S14). . Further, the central processing unit 48 sets the flag F (x, y) to the value “0”, thereby returning to the state where the peak of the luminance value is not detected (step 15).

As described above, the flag F (x, y) = 0 is set after the valley of the luminance value f _i (x, y) is detected, whereby the second peak search process (step S05) and 2 First peak determination processing (step S09) is executed. The central processing unit 48 executes the second peak search process and the confirmation process by the same procedure as the above-described first peak search process and the confirmation process.

FIG. 13 is a diagram for explaining a search process for the second peak. The black circles in the figure indicate the actually acquired luminance value f _i (x, y), and the solid line indicates the transition of the luminance value f _i (x, y). On the other hand, the broken line in the figure shows the transition of the luminance value f _i (x, y) predicted from the next image f _{i + 1} onward. The number of peaks c (x, y) = 1 is set.

Referring to FIG. 13, central processing unit 48 calculates difference Δi between image number n (x, y) of the latest peak and image number i. This difference Δi corresponds to the number of images from the latest peak image number n (x, y) to image number i. The central processing unit 48 compares the number of images Δi with the threshold value _Td . The threshold _Td is set to a predetermined value in the second and subsequent peak search processes.

The central processing unit 48 compares the relative luminance value d _i (x, y) of the pixel (x, y) with the intensity d _max (x, y) of the latest peak candidate. When the relative luminance value d _i (x, y) is larger than d _max (x, y), the central processing unit 48 updates the value of d _max (x, y) to the relative luminance value d _i (x, y). (D _max (x, y) = d _i (x, y)). The central processing unit 48 further updates the image number p _max (x, y) of the latest peak candidate to i (p _max (x, y) = i). The central processing unit 48 sets the latest peak image number n (x, y) to i and sets the flag F (x, y) to the value “1”. As a result, the determination process for the second peak is executed.

In the peak detection process (step S30 in FIG. 5), which is the first stage process, the central processing unit 48 performs the above-described peak search process, peak determination process, valley search process, and valley determination process with the number of peaks c (x, y) is repeated until it reaches the upper limit value N _p. As a result, for each pixel (x, y) on the image fi, N _p image numbers n _j (x, y) having a peak luminance value are detected and stored in the storage unit 46.

In this embodiment, the central processing unit 48, a peak detection process performed in the first stage, capture device 42 from the timing when the image f _i is transferred to the storage unit 46 from the capture device 42 is next image It is executed using a period until the timing at which sampling of _{fi + 1} is started. For example, assuming that the resolution of the CCD camera 30 is 640 × 480 and the luminance value f _i (x, y) is 1 byte, the size of the image data transferred from the capture device 42 to the storage unit 46 is 307,200 bytes. It becomes. On the other hand, if the frequency of the vertical synchronization signal of the CCD camera 30 is 120 Hz, the image sampling period is 1/120 seconds. Accordingly, the capture device 42 captures 307,200 bytes of image data every 1/120 second (approximately 8.3 milliseconds) and transfers the image data to the storage unit 46 of the processing device 44. Data transfer from the capture device 42 to the storage unit 46 can be performed in about 2 milliseconds by using DMA transfer. Therefore, the processing device 44 executes the first stage processing by using the time of about 6.3 milliseconds excluding the about 2 milliseconds required for data transfer out of the sampling period of about 8.3 milliseconds.

In this manner, the first stage processing is executed using the idle time after the data transfer for every sampling period of the image. Thus, when the sampling of all the images within the search range is completed, the peak image numbers are stored in the two-dimensional array n _j of the storage unit 46 in the order of detection.

(Shape measurement process)
Next, the procedure of the shape detection process (step S60 in FIG. 5) which is the second stage process will be described in detail.

As described above, the storage unit 46 stores a total of N _p two-dimensional arrays n _j that hold peak image numbers. Of these, n ₁ stores the image number of the first peak. n ₂ , n ₃ ,... n _Np store the image numbers of the second and subsequent peaks, respectively.

The central processing unit 48, a two-dimensional array n ₁ in order to determine the exact image number luminance value becomes a peak. Specifically, the central processing unit 48 refers to the two-dimensional array n _j and reads the peak image number p (= n _j (x, y)) for each pixel. Then, the central processing unit 48 uses the front and rear ± n sheets total (2n + 1) images around the image f _p of the image number p of the peak, the peak point of the contrast value M _i ♯ (x, y) Ask for.

The contrast value M _i # will be described with reference to FIG. FIG. 14A shows the relationship between the image number i and the brightness value f _i (x, y). FIG. 14B is a diagram illustrating the relationship between the image number i and the contrast value M _i # (x, y). FIG. 14C shows the relationship between the position of the Z stage and the moving speed.

14A to 14C, the luminance value f _i (x, y) and the contrast value M _i # (x, y) both show peaks in the vicinity of the image number p. The position of the Z stage corresponding to this peak point is the focal position of the pixel (x, y).

The contrast value M _i # (x, y) indicates the envelope of the luminance value f _i (x, y) shown in FIG. Contrast value _{M i} ♯ a total of about ± 2 sheets around the image _{f i} 5 images _{f i-2, f i-} 1, f i, using the luminance values of _{f i + 1, f i +} 2, the following Calculated by equation (3).

The central processing unit 48, a total of around the image _{f p} of the image number p (2n + 1) images _{f p-n, f p-} n + 1, ···, f p-1, f p, f p + 1, · For each of f _{p + n−1} and f _{p + n} , the contrast value M _i # (x, y) is calculated using the above equation (3). That is, the central processing unit 48 adds (2n + 1) contrast values M _p−n #, M _{p−n + 1} #,..., M _p−1 #, M _p #, M _{p + 1} #,. _{p + n-1} # and Mp _{+ n} # are calculated.

As shown in FIG. 14B, the contrast value M _i # has a symmetrical mountain-shaped tendency with the peak point as the center. Therefore, a curve indicating the contrast value M _i # can be approximated using a quadratic function or a Gaussian function. Therefore, the central processing unit 48 approximates the contrast value M _i # with a quadratic function or a Gaussian function, and obtains the image number p at which the contrast value M _i # peaks from the obtained function. Then, the position of the Z stage corresponding to the image number p is set to the height of the pixel (x, y). When the Z stage position corresponding to the image number p is Z _j (x, y), Z _j (x, y) can be expressed by the following equation (4) using the center wavelength λ of white light. it can.

In the present embodiment, the configuration in which the contrast value M _i # is approximated by a quadratic function or a Gaussian function has been described. However, the centroid position of (2n + 1) contrast values M _i # is obtained and the obtained centroid position is obtained. May be the peak point. This barycentric position indicates the center position of the symmetrical data as shown in FIG. The Z stage position Z _j (x, y) corresponding to the image number p indicating the center of gravity position can be calculated using the following equation (5).

As described above, the central processing unit 48 corresponds to the image number p at which the contrast value M _i # (x, y) peaks for each pixel (x, y) based on the two-dimensional array n _j. The Z stage position Z _j (x, y) is obtained. That is, the central processing unit 48 corresponds to each of the two-dimensional arrays n ₁ , n ₂ ,... N _Np in total, N _p Z stage positions Z ₁ (x, y), Z ₂ (x, y ,... Z _Np (x, y) is calculated. Calculated N _p number of Z stage position is stored in the storage unit 46.

Next, the central processing unit 48 uses the Z stage position Z _j (x, y) (1 ≦ j ≦ N _p ) stored in the storage unit 46 to form the transparent films 3 a to 3 c ( Each film thickness in FIG. 1) is calculated.

FIG. 15 is a diagram for explaining a method of calculating the film thickness of each transparent film. Referring to FIG. 15, when the transparent film 3 is composed of three transparent films 3a to 3c, a total of four Z stage positions Z ₁ (x, y), Z ₂ (x, y), Z ₃ (x, y), Z ₄ (x, y) is calculated. The Z stage position Z ₁ (x, y) is a Z stage position corresponding to the image number n ₁ (x, y) of the _first peak. The image number n ₁ (x, y) of the first peak indicates the image number at which the intensity of the interference light due to the reflected light from the back surface of the lowermost transparent film 3c peaks.

The Z stage position Z ₂ (x, y) is a Z stage position corresponding to the image number n ₂ (x, y) of the _second peak. The image number n ₂ (x, y) of the _second peak indicates the image number at which the intensity of the interference light due to the reflected light from the surface of the transparent film 3c (the back surface of the intermediate transparent film 3b) peaks. .

The Z stage position Z ₃ (x, y) is a Z stage position corresponding to the image number n ₃ (x, y) of the _third peak. The image number n ₃ (x, y) of the _third peak indicates the image number where the intensity of the interference light due to the reflected light from the surface of the transparent film 3b (the back surface of the uppermost transparent film 3a) peaks. Yes.

The Z stage position Z ₄ (x, y) is a Z stage position corresponding to the image number n ₄ (x, y) of the _fourth peak. The image number n ₄ (x, y) of the _fourth peak indicates the image number where the intensity of the interference light due to the reflected light from the surface of the transparent film 3a peaks.

Here, when calculating the thickness of the lowermost transparent film 3c is, Z stage position _Z 1 (x, y) and Z stage position _Z 2 (x, y) by the following equation (6) the difference _{D c} between the calculate. When placing the refractive index of the transparent film 3c and n _c, the thickness t _c of the transparent film 3c can be calculated by the following equation (7).

By the same method, the film thickness t _b of the transparent film 3b is set so that the difference D _b between the Z stage position Z ₂ (x, y) and the Z stage position Z ₃ (x, y) and the refractive index n of the transparent film 3 _b are obtained. _{Using b} , it can be calculated by the following equation (8).

The thickness _{t a} of the transparent film 3a uses a Z stage position _Z 3 (x, y) and Z stage position _Z 4 (x, y) the refractive index _{n a} of the difference _{D a,} and the transparent film _{3 a} with Thus, it can be calculated by the following equation (9).

The central processing unit 48 compares each of the calculated film thicknesses t _a , t _b , and t _c of the transparent films 3a, 3b, and 3c with a threshold value to determine whether the applied ink has a desired film thickness. It can be determined whether or not. In each transparent film, the total value of the film thickness t calculated for each pixel can be regarded as the volume of the transparent film. Therefore, by comparing the total value with the threshold value, it can be determined whether or not the amount of applied ink is a desired application amount.

Furthermore, the central processing unit 48 can calculate the height of the uneven portion formed on the surface of the transparent film using the Z stage position Z _j (x, y). For example, the Z stage position Z ₂ (x, y) represents the height of the surface of the transparent film 3c in the pixel (x, y). Therefore, by comparing the Z stage position Z ₂ (x, y) among a plurality of pixels, the height of the uneven portion in the transparent film 3c can be calculated.

In the present embodiment, the coherence distance in the interference light can be shortened by setting the wavelength band of the white light applied to the transparent film as wide as possible. FIG. 16 is a diagram for explaining the coherence distance in the interference light. FIG. 16 shows a change in the intensity of the interference light when the distance from the surface of the transparent film to the objective lens is changed. In the figure, the horizontal axis indicates the distance from the surface of the transparent film to the objective lens, and the vertical axis indicates the intensity of the interference light.

Referring to FIG. 16, the coherence distance represents the maximum optical path length difference at which white light divided by the beam splitter of the objective lens interferes. When the center wavelength of white light is λ ₀ and the wavelength band is Δλ, the coherence distance L is given by the following equation (10). According to the following expression (10), for example, when the center wavelength of white light is λ ₀ = 560 nm and the wavelength band Δλ = 200 nm, the coherence distance L = 1568 nm.

In the waveform of the interference light intensity shown in FIG. 3, the interference light by the reflected light from the surface of the transparent film and the interference light by the reflected light from the back surface of the transparent film are shortened by shortening the coherence distance of each interference light. The overlap with can be reduced. As a result, the two interference lights can be easily separated.

In the present embodiment, a white LED is used as the incident light source 12 (FIG. 1). The emission spectrum of the white LED has two peaks at wavelengths of 450 nm and 560 nm. Since the spectral width is narrower in the vicinity of the peak at the wavelength of 450 nm than in the vicinity of the peak at the wavelength of 560 nm, the wavelength band Δλ cannot be widened when the center wavelength of white light is λ ₀ = 450 nm.

Therefore, in this embodiment, in order to set the center wavelength λ _{0 of} white light to 560 nm, the filter 14 is used to selectively transmit light in the vicinity of the wavelength 560 nm. As such a filter 14, a low-pass filter that transmits white light on a long wavelength side with a boundary near a wavelength of 480 nm corresponding to a valley between a peak of a wavelength of 450 nm and a peak of a wavelength of 560 nm in an emission spectrum of white light is used. Can do. Thereby, since a wavelength band Δλ of 200 nm or more can be obtained, the coherence distance L can be shortened. Therefore, the interference light by the reflected light from the surface of the transparent film and the interference light by the reflected light from the back surface of the transparent film can be easily separated.

[Configuration of coating device]
Finally, an outline of a coating apparatus will be described as an example of an apparatus to which the shape measuring apparatus according to the present embodiment is applied.

FIG. 17 is a perspective view showing an overall configuration of coating apparatus 1 according to the present embodiment. The coating apparatus 1 according to the present embodiment is configured to be able to apply a transparent ink (liquid material) over a plurality of layers on the main surface of the substrate 5. Referring to FIG. 17, a coating apparatus 1 includes a coating head unit including an observation optical system 2, a CCD camera 30, a cutting laser device 4, an ink coating mechanism 7, and an ink curing light source 6, and the coating head. Z stage 8 for moving the part in the vertical direction (Z-axis direction) with respect to substrate 5 to be coated, X stage 9 for mounting Z stage 8 and moving in the X-axis direction, and Y for mounting substrate 5 The Y stage 11 that is moved in the axial direction, the control computer 40 that controls the operation of the entire apparatus, the monitor 50 that displays images taken by the CCD camera 30, and the control computer 40 are given commands from the operator. And an operation panel 52 for inputting.

The observation optical system 2 includes a light source for illumination, and observes the surface state of the substrate 5 and the state of ink applied by the ink application mechanism 7. An image observed by the observation optical system 2 is converted into an electrical signal by the CCD camera 30 and displayed on the monitor 50. The cutting laser device 4 removes unnecessary portions on the substrate 5 by irradiating them with laser light via the observation optical system 2.

The ink application mechanism 7 applies ink on the main surface of the substrate 5. The ink curing light source 6 includes, for example, a CO ₂ laser, and cures the ink applied by the ink application mechanism 7 by irradiating it with laser light.

This apparatus configuration is an example. For example, the Z stage 8 on which the observation optical system 2 is mounted is mounted on the X stage, the X stage is mounted on the Y stage, and the Z stage 8 can be phased in the XY direction. A configuration called a gantry system may be used, and any configuration may be used as long as the Z stage 8 on which the observation optical system 2 and the like are mounted can be moved relative to the target substrate 5 in the XY directions.

Next, an example of an ink application mechanism using a plurality of application needles will be described. FIG. 18 is a perspective view showing the main parts of the observation optical system 2 and the ink application mechanism 7. Referring to FIG. 18, this coating apparatus 1 includes a movable plate 15, a plurality (for example, five) objective lenses 19 having different magnifications, and a plurality (for example, five) for applying inks made of different materials. And a coating unit 17.

The movable plate 15 is provided so as to be movable in the X-axis direction and the Y-axis direction between the lower end of the observation barrel 2 a of the observation optical system 2 and the substrate 5. Further, for example, five through holes 15 a are formed in the movable plate 15.

The objective lens 19 is fixed to the lower surface of the movable plate 15 so as to correspond to the through holes 15a at predetermined intervals in the Y-axis direction. Each of the five coating units 17 is disposed adjacent to the five objective lenses 19. By moving the movable plate 15, a desired coating unit 17 can be disposed above the target substrate 5.

19 (a) to 19 (c) are views of the main part seen from the direction A in FIG. 18, and are diagrams showing the ink application operation. The application unit 17 includes an application needle 170 and an ink tank 1172. First, as shown in FIG. 19A, the application needle 170 of the desired application unit 17 is positioned above the target substrate 5. At this time, the tip of the application needle 170 is immersed in the ink in the ink tank 172.

Next, as shown in FIG. 19B, the application needle 170 is lowered and the tip of the application needle 170 protrudes from the bottom hole of the ink tank 172. At this time, ink adheres to the tip of the application needle 170. Next, as shown in FIG. 19C, the application needle 170 and the ink tank 172 are lowered to bring the tip of the application needle 170 into contact with the substrate 5, and ink is applied to the substrate 5. Thereafter, the state returns to the state of FIG.

The ink application mechanism using a plurality of application needles is not described in detail since various other techniques are known. For example, it is shown in Patent Document 1. For example, the application device 1 can apply a desired ink of a plurality of inks by using a mechanism as shown in FIG. 18 as the ink application mechanism 7, and can also apply a desired application of a plurality of application needles. The ink can be applied using a diameter application needle.

The head unit 10 (FIG. 1) of the shape measuring apparatus according to the present embodiment is provided in the observation optical system 2 of the coating apparatus 1, for example. The control computer 40 controls the ink application mechanism 7 to perform an ink application operation, and then moves the Z stage 8 to move the head unit 10 to a predetermined position above the surface of the ink application part (transparent film). Position. The control computer 40 further takes an image of interference light by the CCD camera 30 while moving the Z stage 8 relative to the substrate 5. The control computer 40 detects the Z stage position where the interference light intensity reaches a peak for each pixel, and calculates the film thickness of the ink application part (transparent film) or the height of the uneven part using the detected Z stage position. .

(Function and effect)
According to the shape measuring device, the coating device, and the shape measuring method according to the embodiment of the present invention, an image is obtained while relatively moving the transparent film formed by laminating two or more transparent films and the objective lens in the vertical direction. A plurality of peaks can be detected and three or more peaks appearing in the intensity of the interference light can be detected for each pixel constituting the captured image. Thereby, the film thickness of each transparent film and the height of the concavo-convex part formed on the surface of each transparent film can be detected.

Further, in the first-stage processing for detecting the image number at which the luminance value has a peak for each pixel constituting the image, three or more appearing in the change in the luminance value by a simple arithmetic processing using the luminance value of each pixel. Can be detected. Therefore, since the control computer is not required to have a high calculation processing capability, the shape measuring apparatus can be configured simply and inexpensively.

Furthermore, since the first stage processing can be performed using the idle time (vacant time after image transfer) within the imaging cycle of the imaging apparatus, numerical calculation processing after all images have been imaged Can be reduced. As a result, the working time of the shape measuring process can be shortened.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 coating device, 2,25 observation optical system, 2a observation barrel, 3,3a-3c transparent film, 4 cutting laser device, 5 substrate, 6 ink curing light source, 7 ink coating mechanism, 8 Z stage, 9 X Stage, 10 head part, 11 Y stage, 12 incident light source, 14 filter, 15 movable plate, 15a through hole, 16 condensing lens, 17 coating unit, 18 half mirror, 19, 20 objective lens, 22 lens, 24 reference mirror , 26 beam splitter, 28 imaging lens, 30 CCD camera, 30a imaging surface, 40 control computer, 42 capture device, 44 processing device, 45 drive device, 46 storage unit, 48 central processing unit, 50 monitor, 52 operation panel.

Claims (10)

1. A shape measuring device for measuring the thickness of a transparent film or the height of an uneven portion formed on the surface of the transparent film,
   The transparent film is formed by laminating a single layer or a plurality of transparent films,
   The illumination device that outputs white light, and the white light emitted from the illumination device is separated into two light beams, one of which is irradiated on the surface of the transparent film and the other is irradiated on the reference surface. An objective lens for interfering reflected light to obtain interference light, an observation optical system for observing the interference light obtained via the objective lens, and an imaging device for photographing the interference light via the observation optical system A head portion including
   A positioning device for relatively moving the head part and the transparent film to position the head part at a desired position above the surface of the transparent film;
   After the objective lens is positioned above the transparent film by controlling the positioning device and the imaging device, the interference light is continuously changed while the vertical distance from the transparent film to the objective lens is continuously changed. A plurality of images, and a shape detection unit that detects the film thickness of the transparent film or the height of the concavo-convex portion based on the captured images of the plurality of images,
   The shape detector
   In the imaging cycle of the imaging apparatus, image numbers are assigned to the plurality of captured images in the order in which they were captured, and a plurality of image numbers having a peak luminance are obtained for each of the plurality of pixels constituting the image. The first stage of processing;
   After the imaging device captures the plurality of images, the film thickness of the transparent film or the uneven portion is determined based on a plurality of image numbers at which the luminance is obtained by the first stage processing. A shape measuring device that executes a second stage process of detecting height.
2. The shape measuring apparatus according to claim 1, wherein the shape detecting unit calculates the volume of the transparent film by summing up the film thicknesses of the transparent film detected for each pixel in the second stage processing. .
3. The shape detection unit, in the processing of the first step, an image photographed in the current shooting period, the image number i (i is an integer of 1 or more) and the image f _i of,
   Wherein for each pixel of the image f _i, calculates the average value of the brightness in the consecutive predetermined number of images including the image f _i, and calculates the luminance relative value indicating the luminance deviation relative to the average value, and the Set a pixel whose relative luminance value is equal to or greater than a threshold value as a candidate pixel whose luminance shows a peak,
   Luminance relative value of the candidate pixel in the image f _i is greater than the relative luminance value of the most recent of the candidate pixel updates the image number of candidates which the luminance has a peak in the image number i,
   3. The shape according to claim 1, wherein when the threshold image number of candidate image numbers having the peak luminance is not continuously updated, the image number i is determined as the image number having the peak luminance. measuring device.
4. The shape detection unit, in the processing of the first step, to set the pixel luminance relative value in the image f _i is minimized, the candidate pixels exhibiting the valley between the peaks and the peak brightness,
   Minimum value of the luminance relative value in the image f _i is smaller than the minimum value of the most recent of the luminance relative value updates the image number of candidates which the luminance becomes valley image number i,
   After determining the image number at which the luminance reaches a peak, if the minimum value of the relative luminance value is not continuously updated by the threshold number, the image number i is determined as an image number at which the luminance is a valley. The shape measuring apparatus according to claim 3.
5. The shape detection unit repeatedly performs, in this order, a process of determining an image number at which the luminance reaches a peak and a process of determining an image number at which the luminance is a trough. The shape measuring apparatus according to claim 4, wherein a plurality of numbers are obtained.
6. In the second-stage processing, the shape detection unit is configured to have ± n sheets (n is a front and rear) centered on an image of the image number at which the luminance reaches a peak for each of the plurality of image numbers at which the luminance reaches a peak. The brightness envelope is calculated using a total of (2n + 1) images of an integer equal to or greater than 1, and the image number when the envelope becomes a peak is determined as the image number where the brightness reaches a peak. The position of the head portion corresponding to the image number at which the luminance is peaked is calculated,
   The shape measuring apparatus according to claim 1, wherein the film thickness of the transparent film or the height of the uneven portion is detected based on the calculated positions of the plurality of head portions.
7. The lighting device is a white LED,
   The filter further includes a filter that is provided between the illumination device and the objective lens and selectively transmits white light on a long wavelength side of two peaks of an emission spectrum of the white LED. 7. The shape measuring device according to any one of items 6 to 6.
8. An application mechanism for forming a transparent film formed by laminating a single layer or a plurality of transparent films by applying a transparent liquid material on the main surface of the substrate;
   An illumination device that outputs white light, and the white light emitted from the illumination device is separated into two luminous fluxes, one of which is irradiated on the surface of the transparent film and the other is irradiated on the reference surface, and reflection from both surfaces. An objective lens for interfering light to obtain interference light, an observation optical system for observing the interference light obtained via the objective lens, and an imaging device for photographing the interference light via the observation optical system; Including a head portion,
   A positioning device for relatively moving the head part and the application part to position the head part at a desired position above the surface of the application part;
   By controlling the positioning device and the imaging device, after positioning the objective lens above the application unit, the interference light is continuously changed while changing the vertical distance from the application unit to the objective lens. A plurality of images, and a shape detection unit that detects the film thickness of the transparent film or the height of the concavo-convex portion based on the captured images of the plurality of images,
   The shape detector
   In the imaging cycle of the imaging apparatus, image numbers are assigned to the plurality of captured images in the order in which they were captured, and a plurality of image numbers having a peak luminance are obtained for each of the plurality of pixels constituting the image. The first stage of processing;
   After the imaging device captures the plurality of images, the film thickness of the coating portion or the unevenness portion is determined based on the plurality of image numbers at which the luminance is obtained by the first stage processing. A coating apparatus that executes a second stage process of detecting the height.
9. A shape measuring method for measuring a film thickness of a transparent film or a height of an uneven portion formed on the surface of the transparent film,
   The transparent film is formed by laminating a single layer or a plurality of transparent films,
   The illumination device that outputs white light, and the white light emitted from the illumination device is separated into two light beams, one of which is irradiated on the surface of the transparent film and the other is irradiated on the reference surface. An objective lens for interfering reflected light to obtain interference light, an observation optical system for observing the interference light obtained via the objective lens, and an imaging device for photographing the interference light via the observation optical system Positioning the head portion at a desired position above the surface of the transparent film;
   After the objective lens is positioned above the transparent film, a plurality of images of the interference light are photographed while continuously changing a vertical distance from the transparent film to the objective lens, and the plurality of photographed images Detecting the film thickness of the transparent film or the height of the concavo-convex portion based on the image of
   The step of detecting the film thickness of the transparent film or the height of the concavo-convex part,
   In the imaging cycle of the imaging apparatus, image numbers are assigned to the plurality of captured images in the order in which they were captured, and a plurality of image numbers having a peak luminance are obtained for each of the plurality of pixels constituting the image. The first stage of processing;
   After the imaging device captures the plurality of images, the film thickness of the transparent film or the uneven portion is determined based on a plurality of image numbers at which the luminance is obtained by the first stage processing. A shape measuring method for executing a second stage process of detecting height.
10. In the step of detecting the film thickness of the transparent film or the height of the uneven portion, the volume of the transparent film is obtained by summing the film thicknesses of the transparent film detected for each pixel in the second stage process. The shape measuring method according to claim 9, wherein:

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