JP6322320B2 - Liquid discharge nozzle interval detection method and liquid discharge apparatus - Google Patents

Description

  The present invention relates to a liquid discharge nozzle interval detection method for detecting an interval between a liquid discharge nozzle and a target surface of a liquid discharge target, and a liquid discharge apparatus for detecting an interval by the method.

  Patent Document 1 proposes a liquid ejection apparatus with an observation optical system that draws fine electrode patterns, wiring patterns, etc. on the surface of a color filter substrate for a liquid crystal panel, a semiconductor substrate for an integrated circuit, etc. using a liquid ejection nozzle. Has been. In such a liquid discharge apparatus, it is necessary to accurately control the interval between the liquid discharge nozzle and the drawing target substrate surface. If the interval fluctuates, drawing cannot be performed with high accuracy by the liquid discharge nozzle. Therefore, it is desirable to perform drawing with high accuracy while detecting the interval between drawing portions in real time.

  Patent Document 2 proposes an interval measurement method for accurately measuring the interval between the coating liquid discharge port surface of the applicator and the application surface of the application member. In this interval measurement method, a real image of the end of the discharge port surface and a reflection image of the end of the discharge port surface on the coating surface are imaged, and the length between these real images and the reflection image is measured, Based on this, the interval between the actual discharge port surface and the coated surface is calculated.

International Publication No. 2012/140689 JP 2013-148408 A

  If the method proposed in Patent Document 2 is used, the interval between the liquid discharge nozzle and the target surface at the liquid discharge position can be accurately detected. This method is based on the premise that the tip of the liquid discharge nozzle is clearly displayed on the target surface. In addition, it is assumed that in the obtained real image and mirror image of the nozzle tip of the liquid discharge nozzle, the edge of the nozzle tip can be reliably recognized.

  However, depending on the amount of illumination light, the material and surface properties of the liquid discharge nozzle, the surface properties of the target surface, etc., a clear mirror image of the nozzle tip may not be obtained by the observation optical system that observes the nozzle tip of the liquid discharge nozzle. is there.

  In the case of fine drawing, the nozzle tip and the target surface are opposed to each other at a minute interval. In the process in which the liquid discharged from the nozzle tip adheres to the target surface, a connected state is formed between the nozzle tip and the target surface. When a real image and a mirror image of the nozzle tip are observed in this state, the nozzle tip edge in those images may not be recognized.

  An object of the present invention is to provide a liquid discharge nozzle interval detection method capable of detecting an interval between a nozzle tip and a target surface even when the conventional interval measurement method cannot be used as described above, and An object of the present invention is to provide a liquid ejection device that detects an interval by a method.

The liquid discharge nozzle interval detection method of the present invention includes:
Capture a real image of the nozzle tip of the liquid discharge nozzle and a mirror image of the nozzle tip reflected on the target surface of the liquid discharge object facing the liquid discharge nozzle;
Based on the distance between the real image and the mirror image of the nozzle tip edge of the imaged nozzle tip, the interval between the nozzle tip edge and the target surface is detected,
When the discharge liquid discharged from the liquid discharge nozzle becomes an obstacle and the nozzle tip edge of the imaged nozzle tip cannot be identified by image analysis,
Instead of the distance between the real image and the mirror image of the nozzle tip edge of the nozzle tip portion, the distance between the real image and the mirror image of the interval detection indicator formed at a position deviated from the nozzle tip edge in the liquid discharge nozzle Measure and
A distance between the nozzle tip edge and the target surface is detected based on the distance.

  According to the present invention, even when the discharge liquid is connected between the nozzle tip edge and the target surface, the distance between the liquid discharge nozzle and the target surface is based on the distance between the real image and the mirror image of the indicator. The interval can be detected. In addition, it is desirable to form the indicator using a highly reflective paint or the like. In this way, even when a clear mirror image of the tip of the nozzle cannot be obtained due to the amount of illumination light, the material / surface properties of the liquid discharge nozzle, the surface properties of the target surface, etc., Mirror images that can be recognized with high accuracy can be acquired.

Next, the liquid ejection device of the present invention is
A liquid discharge nozzle;
An indicator formed in a portion away from the nozzle tip edge in the liquid discharge nozzle;
A work table on which an object having a liquid discharge target surface is placed in a state where the target surface faces the liquid discharge nozzle;
Illuminating the target surface of the target object placed on the work table and the liquid discharge nozzle facing the target surface from an oblique direction with respect to both the target surface and the nozzle central axis of the liquid discharge nozzle. An oblique illumination optical system that emits light;
An image of the indicator of the liquid ejection nozzle irradiated by the illumination light, and a nozzle observation optical system for observing a mirror image of the indicator reflected on the target surface;
First image processing for measuring a distance between a real image and a mirror image of the indicator observed by the nozzle observation optical system and detecting an interval from a nozzle tip edge of the liquid discharge nozzle to the target surface based on the distance It has the part.

  Here, the liquid ejection apparatus having the above-described configuration includes a counter mirror that recursively reflects a regular reflection light component of the illumination light irradiated onto the target surface by the oblique illumination optical system, and the oblique illumination optical system and the nozzle observation The optical system is preferably arranged on the same axis.

  In this way, the oblique illumination optical system and the nozzle observation optical system can be coaxially arranged on the same side with respect to the discharge liquid observation optical system and the liquid discharge nozzle. Therefore, the apparatus configuration can be reduced in size and size.

  The liquid ejecting apparatus measures a distance between a real image and a mirror image of the nozzle tip observed by the observation optical system, and detects a distance between the nozzle tip and the target surface based on the distance. It is desirable to include a two-image processing unit and a control unit that causes the interval to be calculated by at least one of the first image processing unit and the second image processing unit.

  Furthermore, it is desirable that the liquid ejection apparatus has a ejection liquid observation optical system that observes the state of the liquid ejected on the target surface with the nozzle central axis of the liquid ejection nozzle as a central optical axis.

It is a schematic block diagram which shows the basic composition of the liquid discharge apparatus which concerns on the reference example of this invention. FIG. 2 is a schematic configuration diagram illustrating a main part of the liquid ejection device in FIG. 1. It is explanatory drawing which shows the nozzle gap detection operation | movement of the liquid discharge apparatus of FIG. It is a schematic block diagram which shows the principal part of the liquid discharge apparatus which concerns on embodiment of this invention. FIG. 5 is an explanatory diagram illustrating a nozzle gap detection operation of the liquid ejection device in FIG. 4. It is explanatory drawing which shows the modification of a liquid discharge apparatus. It is explanatory drawing which shows the modification of a liquid discharge apparatus.

  First, a liquid ejection apparatus according to a reference example of the present invention will be described, and then an embodiment of the liquid ejection apparatus to which the present invention is applied will be described.

[Reference example]
FIG. 1 is a schematic configuration diagram illustrating a basic configuration of a liquid ejection apparatus according to a reference example of the present invention, and FIG. 2 is a schematic configuration diagram illustrating a main part of the liquid ejection apparatus. The liquid ejection device is used, for example, for repairing a defect or the like of a wiring pattern formed on a substrate surface (target surface) of a substrate (ejection target) such as a color filter substrate or a semiconductor substrate.

  A basic configuration of the liquid ejection apparatus 1 will be described with reference to FIG. The liquid discharge apparatus 1 includes a liquid discharge nozzle 2 (hereinafter, simply referred to as “nozzle 2”) that discharges a liquid for forming a wiring pattern as fine droplets. The nozzle 2 is supplied with a liquid from a liquid supply source (not shown) via a liquid supply pipe 3. Various known mechanisms can be adopted as a mechanism for discharging the fine droplets from the nozzle 2.

A work table 4 is disposed below the nozzle 2. On the work table 4, a substrate 5 that is a liquid discharge target is placed. The substrate 5 on the work table 4 has a predetermined distance from the nozzle front end surface 2a of the nozzle 2 (hereinafter sometimes referred to as “nozzle gap”). Confront. In this example, the substrate 5 is disposed so that the substrate surface 5a is horizontal, and the nozzle 2 is disposed such that the nozzle center axis 2A is vertical.

  The nozzle 2 is mounted on a Z stage 6 for gap control, and the Z stage 6 moves the liquid discharge nozzle 2 in a direction along the nozzle center axis 2A, in this example, in the vertical direction by a Z stage controller 7. The drive control of each unit such as the drive control of the nozzle 2 and the drive control of the Z stage controller 7 is performed by the control unit 10 including the first image processing unit 8 and the second image processing unit 9 for calculating the nozzle gap.

  The nozzle 2 is provided with a discharge liquid observation optical system 11 coaxially. That is, the ejected liquid observation optical system 11 is an optical system having the central axis of the nozzle 2A as a central optical axis, and an enlarged image of the liquid ejected on the substrate surface 5a can be observed by the observation camera 13 through the objective lens 12. is there. The image captured by the observation camera 13 is supplied to the third image processing unit 14 for calculating the volume of the ejected liquid in the control unit 10, and the nozzle gap and the like are adjusted based on the volume of the ejected liquid and the like.

  Next, the liquid ejection apparatus 1 includes an illumination optical system 15. The illumination optical system 15 obliquely illuminates the substrate surface 5a and the nozzle 2 of the substrate 5 placed on the work table 4 with illumination light obliquely upward from both the substrate surface 5a and the nozzle center axis 2A. It is. The illumination light from the illumination light source of the illumination optical system 15 is bent perpendicularly downward in the vertical direction by the beam splitter 16 and then directed obliquely downward toward the substrate surface 5a and the nozzle 2 by the deflection mirror 17, Irradiate.

  The liquid ejection apparatus 1 also includes a nozzle observation optical system 18 having an observation optical axis that is coaxial with the illumination optical axis of the illumination optical system 15. The nozzle observation optical system 18 includes a counter mirror 19 that retroreflects the specularly reflected light component of the illumination light L1 applied to the nozzle 2 and the substrate surface 5a. (Field observation) is possible. A real image of the nozzle tip 2b of the nozzle 2 and a mirror image of the nozzle tip 2b reflected on the substrate surface 5a are observed by the observation camera 21 through the objective lens 20.

  The real image and the mirror image of the nozzle tip 2b observed by the observation camera 21 are supplied to the second image processing unit 9 of the control unit 10. The second image processing unit 9 measures the distance between the nozzle tip surface 2a (nozzle tip edge) in the real image and the mirror image of the nozzle tip 2b by image processing, and based on this distance, the actual nozzle tip surface 2a and the substrate The distance between the surface 5a, that is, the nozzle gap G is detected.

  Here, as the nozzle observation optical system 18, two sets of observation optical systems may be arranged at different positions around the nozzle center axis 2A. In this case, the discharged liquid observation optical system 11 and the two sets of nozzle observation optical systems simultaneously observe the liquid droplets discharged onto the substrate surface 5a, and the third image processing unit 14 of the control unit 10 The shape, volume, and the like of the height, diameter, etc. of the droplet can be calculated, and based on this, the droplet discharge amount can be controlled.

In addition to the above configuration, the liquid ejection apparatus 1 includes a marker light imaging irradiation optical system 22 shown in FIG. Referring to FIG. 2, the marker light imaging irradiation optical system 22 forms and irradiates the marker light L2 having the nozzle center axis 2A as the central optical axis on the substrate surface 5a. The marker light imaging irradiation optical system 22 includes a beam splitter 24 disposed on the optical path of the light source 23 and the ejected liquid observation optical system 11 so as to be inclined at an angle of 45 degrees with respect to the optical axis. The marker light L2 emitted from the light source 23 is ejected by the beam splitter 24 from the ejected liquid observation optical system 1.
1 is deflected in a direction along the optical axis 1 and imaged as a light spot S having a predetermined diameter on the substrate surface 5 a via the objective lens 12 of the ejected liquid observation optical system 11.

  The nozzle observation optical system 18 can simultaneously observe the image of the nozzle tip 2b of the nozzle 2 and the image of the light spot S of the marker light L2 formed on the substrate surface 5a within the same field of view. The first image processing unit 8 of the control unit 10 measures the distance from the nozzle tip surface 2a of the nozzle tip 2b observed by the nozzle observation optical system 18 to the light spot S, and sets the nozzle gap G based on the distance. To detect.

  Here, the beam splitter 24 is mounted on the moving stage 25. The moving stage 25 can move the beam splitter 24 in a direction orthogonal to the optical axis of the ejected liquid observation optical system 11 while maintaining its posture. When the beam splitter 24 is moved, the position of the light spot S of the marker light L2 on the substrate surface 5a of the marker light can be moved.

  FIG. 3 is an explanatory diagram illustrating an example of the nozzle gap detection operation of the liquid ejection apparatus 1. In the nozzle observation optical system 18, normally, as shown in FIG. 3A, a real image 2b1 of the nozzle tip 2b and a mirror image 2b2 of the nozzle tip 2b reflected on the substrate surface 5a are observed. In this case, the control unit 10 detects the nozzle gap G by the second image processing unit 9. That is, the distance G1 between the real image 2a1 and the mirror image 2a2 of the nozzle tip surface observed by the nozzle observation optical system 18 is measured, and based on the distance, the distance between the actual nozzle tip surface 2a and the substrate surface 5a ( Nozzle gap) G is calculated. Further, the control unit 10 adjusts the height of the nozzle 2 by the Z stage 6 for gap control so that the nozzle gap G is constant.

  Here, as shown in FIG. 3B, the mirror image 2b2 of the nozzle tip 2b may not be clear, or the mirror image 2b2 may not be observed. For example, depending on the reflection state of the substrate surface 5a, the mirror image 2b2 may not be recognized by image analysis, and their distance may not be measured. In this case, the control unit 10 drives the marker light imaging irradiation optical system 22 to irradiate the liquid discharge position on the substrate surface 5a with the light spot S having a small diameter. Then, the first image processing unit 8 measures the distance G2 between the real image 2a1 of the nozzle tip surface of the real image 2b1 of the observed nozzle tip 2b and the image S1 of the light spot S, and the nozzle gap is based on this distance G2. G is detected.

  In addition, as shown in FIG. 3C, a droplet P discharged from the nozzle 2 may be connected between the nozzle tip surface 2a and the substrate surface 5a. In drawing a fine wiring pattern or the like, the nozzle gap G is maintained at a very small interval, so that the droplet P discharged between the nozzle tip surface 2a and the substrate surface 5a is connected during drawing. Sometimes. In this case, in the observed image, the positions of the real image 2a1 and the mirror image 2a2 of the nozzle tip surface may not be recognized by image analysis. Further, the droplet P at the position formed at the liquid ejection position on the substrate surface 5a becomes an obstacle, and the image S1 of the light spot S of the marker light L2 formed at the position cannot be recognized or recognized. It can be difficult.

  In such a case, the control unit 10 drives the moving stage 25 to move the beam splitter 24, and moves the formation position of the light spot S to a position shifted from the liquid ejection position. Thereby, since the image S1 of the light spot S can be reliably recognized, the nozzle gap G can be detected with high accuracy by the first image processing unit 8.

[Embodiment]
Next, FIG. 4 is a schematic configuration diagram showing a main part of the liquid ejection apparatus 1A according to the embodiment of the present invention. In the liquid ejection apparatus 1A according to the above-described reference example, instead of arranging the marker light imaging irradiation optical system 22, as shown in FIG. An indicator 31 is attached.

  The indicator 31 is a band-shaped member formed in a state in which the outer peripheral surface portion of the nozzle 2 makes one round at a position away from the nozzle front end surface 2a in the nozzle front end portion 2b. As the indicator 31, for example, a highly colored paint or a highly reflective paint can be used.

  Other configurations are the same as those shown in FIG. In FIG. 4, corresponding parts are denoted by the same reference numerals.

  FIG. 5 is an explanatory diagram showing the nozzle gap detection operation of the liquid ejection apparatus 1A. As shown in FIG. 5A, the real image 31a and the mirror image 31b of the indicator 31 are clearly recognized in the real image 2b1 and the mirror image 2b2 of the nozzle tip 2b observed by the nozzle observation optical system 18. The first image processing unit 8 of the control unit 10 measures the distance G3 between the real image 31a and the mirror image 31b of these indicators 31, and detects the nozzle gap G based on the distance G3.

  In this way, as shown in FIG. 5B, even when the discharge droplet P is connected between the nozzle tip 2b and the substrate surface 5a, the indicator located at a position away from the nozzle tip 2b. The real image 31a and the mirror image 31b of the image 31 can be clearly recognized without being disturbed by the image of the ejected droplet P. In addition, a clear mirror image of the nozzle tip 2b may not be observed depending on the state of the substrate surface 5a. However, since the indicator 31 is formed using a material such as highly visible paint, A real image 31a and a mirror image 31b can be obtained. Therefore, the nozzle gap G can be reliably detected.

  Also in this example, when the second image processing unit 9 is arranged in the control unit 10 and a clear mirror image of the nozzle tip 2b is obtained, the distance between the real image and the mirror image of the nozzle tip 2a is measured, The nozzle gap G may be calculated based on this distance.

[Other embodiments]
FIG. 6 is a schematic configuration diagram showing a modified example of the liquid ejecting apparatus 1 or 1A. The liquid ejection apparatus 1B shown in this figure separates the reflected light Lr incident on the nozzle observation optical system 18 and the illumination light L1, and enables the nozzle observation optical system 18 to capture a clear image.

  For this purpose, the illumination light L <b> 1 that is non-polarized light is emitted as linearly polarized light through the first polarizer 41. A quarter-wave plate 42 is disposed in front of the counter mirror 19, and the polarization direction of the return reflected light Lr, which is linearly polarized light reflected and returned by the counter mirror 19, is rotated by 90 degrees. After the reflected reflected light Lr is reflected by the deflecting mirror 17, it passes through the beam splitter 16 and enters the objective lens 20 of the nozzle observation optical system 18 through the second polarizer 43. By the second polarizer 43, only the return reflected light Lr is directed to the objective lens 20. Therefore, unnecessary light components can be removed, and a clear real image and mirror image of the nozzle tip 2b can be observed.

  Since the other configuration is the same as that of the liquid ejecting apparatus 1 or 1A, the description thereof is omitted, and the corresponding parts are denoted by the same reference numerals in FIG.

  Next, FIG. 7 is an explanatory view showing a modification of the illumination optical system 15 and the nozzle observation optical system 18 in the liquid ejecting apparatuses 1, 1A, 1B.

  Referring to this figure, the illumination optical system 15 and the nozzle observation optical system 18 are configured as an integrated optical system unit 51. Further, the optical system unit 51 is disposed so as to be rotatable about the nozzle center axis 2 </ b> A of the nozzle 2. A turning mechanism 52 for turning the optical system unit 51 is disposed on the outer peripheral side of the optical system unit 51. The control unit 10 drives and controls the turning mechanism 52 to turn and position the optical system unit 51 to a predetermined turning position.

  When the substrate surface 5a has irregularities, when the liquid discharge position on the substrate surface 5a is observed from one side, the convex portion of the substrate surface 5a may be in the way and the portion at the liquid discharge position may not be observed. is there. In such a case, the liquid discharge position can be reliably observed by turning the optical system unit 51 and observing the liquid discharge position from different directions.

  A plurality of sets, for example, two sets of optical system units 51 can be fixedly arranged at different angular positions with the nozzle 2 as the center, and these optical system units 51 can be selected and used. It is also possible to arrange a plurality of sets of optical system units 51 so as to be rotatable about the nozzle 2.

DESCRIPTION OF SYMBOLS 1, 1A, 1B Liquid discharge apparatus 2 Liquid discharge nozzle 2a Nozzle front end surface 2a1 Nozzle front end surface real image 2a2 Nozzle front end surface mirror image 2b Nozzle front end portion 2b1 Nozzle front end portion real image 2b2 Nozzle front end mirror image 2A Nozzle central axis 3 Liquid Supply tube 4 Work table 5 Substrate 5a Substrate surface 6 Z stage 7 Z stage controller 8 First image processing unit 9 Second image processing unit 10 Control unit 11 Discharged liquid observation optical system 12 Objective lens 13 Observation camera 14 Third image processing unit DESCRIPTION OF SYMBOLS 15 Illumination optical system 16 Beam splitter 17 Deflection mirror 18 Nozzle observation optical system 19 Opposite mirror 20 Objective lens 21 Observation camera 22 Marker light imaging irradiation optical system 23 Light source 24 Beam splitter 25 Moving stage 31 Indicator 31a Real image 31b Mirror image 41 First polarization Child 42 1/4 wavelength plate 43 Polarizer 51 optical system unit 52 pivoting mechanism L1 illumination light Lr return reflected light L2 marker light S light spots S1 real image of the light spot G nozzle gap G1, G2, G3 distance P droplet

Claims (5)

Capture a real image of the nozzle tip of the liquid discharge nozzle and a mirror image of the nozzle tip reflected on the target surface of the liquid discharge target facing the liquid discharge nozzle;
Based on the distance between the real image and the mirror image of the nozzle tip edge of the imaged nozzle tip, the interval between the nozzle tip edge and the target surface is detected,
When the discharge liquid discharged from the liquid discharge nozzle becomes an obstacle and the nozzle tip edge of the imaged nozzle tip cannot be identified by image analysis,
Instead of the distance between the real image and the mirror image of the nozzle tip edge of the nozzle tip portion, the distance between the real image and the mirror image of the interval detection indicator formed at a position deviated from the nozzle tip edge in the liquid discharge nozzle Measure and
Based on the distance, a gap between the nozzle tip edge and the target surface is detected.
A method for detecting the interval between liquid discharge nozzles. A liquid discharge nozzle;
An indicator formed in a portion away from the nozzle tip edge in the liquid discharge nozzle;
A work table on which an object having a liquid discharge target surface is placed in a state where the target surface faces the liquid discharge nozzle;
Illuminating the target surface of the target object placed on the work table and the liquid discharge nozzle facing the target surface from an oblique direction with respect to both the target surface and the nozzle central axis of the liquid discharge nozzle. An oblique illumination optical system that emits light;
An image of the indicator of the liquid ejection nozzle irradiated by the illumination light, and a nozzle observation optical system for observing a mirror image of the indicator reflected on the target surface;
First image processing for measuring a distance between a real image and a mirror image of the indicator observed by the nozzle observation optical system and detecting an interval from a nozzle tip edge of the liquid discharge nozzle to the target surface based on the distance And
A liquid ejecting apparatus comprising: In claim 2,
A counter mirror that recursively reflects a regular reflection light component of the illumination light irradiated onto the target surface by the oblique illumination optical system;
The oblique illumination optical system and the nozzle observation optical system are arranged on the same axis,
Liquid ejection device. In claim 2 or 3,
A second image processing unit that measures a distance between a real image and a mirror image of the nozzle tip edge observed by the nozzle observation optical system, and detects an interval between the nozzle tip edge and the target surface based on the distance. When,
A liquid ejecting apparatus including: a control unit that causes the interval to be calculated by at least one of the first image processing unit and the second image processing unit. In any one of claims 2 to 4,
Having a discharge liquid observation optical system for observing the state of the liquid discharged to the target surface, with the nozzle central axis of the liquid discharge nozzle as a central optical axis;
Liquid ejection device.