JPH0857382A - Device for detecting liquid-coating nozzle height and method for controlling nozzle height using the same - Google Patents

Abstract

PURPOSE: To provide the device which can sufficiently cope with the warpage, etc., of a platelike work and moreover, enables accurate coating on any positon on the surface of the work with a liquid coating material and also eliminates the severe requirements with respect to processing accuracy of the device. CONSTITUTION: In this device, a nozzle 2 that is moved above a square platelike work 1 while keeping a specific distance from the work 1 to coat the surface of the work 1 with a liquid coating material supplied through the nozzle 2 is provided and plural height sensors 3 and 4 which are arranged adjacent to the nozzle 2 and moved unitedly with the nozzle 2 are also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a height detecting device for a liquid coating nozzle and a nozzle height control method using the same, which is an electronic material or adhesive in the form of liquid, paste, cream or the like. The other liquid material enables steady application to a plate-like work such as a printed circuit board, a ceramic substrate and a glass substrate without being affected by deformation such as warpage.

[0002]

2. Description of the Related Art When a liquid material discharged from a liquid coating nozzle is constantly or continuously applied to the surface of a plate-like work, the plate-like work is deformed such as warped.
When the distance between the nozzle tip and the plate-like work changes, the discharged liquid volume, discharge shape, etc. become unstable, so it is necessary to prevent fluctuations in the distance between the nozzle tip and the surface of the plate-like work. For example, as disclosed in JP-A Nos. 2-169062 and 6-114313, the height of the nozzle tip has been controlled by using one height sensor.

[0003]

However, in such a prior art, in the case where the height sensor disposed adjacent to the coating nozzle and the relative position of the coating nozzle are constant, for example, a rectangular shape is used. When applying liquid to the plate-shaped work that forms the plate, in order to make the height sensor function sufficiently at all times, it is necessary to apply the liquid only within an area that is considerably narrower than the contour shape of the plate-shaped work. There was an inconvenience.

This will be described more specifically with reference to FIG. In the case where the plate-shaped work W has a rectangular contour line shape as shown by a solid line in the drawing, when the liquid material is applied onto the plate-shaped work W by the nozzle N, the nozzle N
And the height sensor S have a relative positional relationship as shown in the drawing, and the relative position is unchanged, the sensor S
While detecting the nozzle height from the plate-like work W, the nozzle N
The maximum area to which the liquid can be applied is the area shown by hatching in the figure. Therefore, it is substantially possible to apply the liquid material to the vicinity of the upper side and the right side of the plate-shaped rake W in the figure. It was impossible.

By the way, in contrast to this, JP-A-6-1143
As disclosed in Japanese Patent Publication No. 13, when the relative position of one height sensor with respect to the nozzle can be changed, the liquid application area is set to the plate-shaped workpiece W shown in FIG.
It is possible to expand to the entire area surrounded by the contour line. However, in this case, the height of the nozzle cannot be controlled with the required accuracy unless the flatness between the axis for moving the nozzle and the sensor moving mechanism is kept within a few μm. There was a problem with accuracy.

The present invention has been made as a result of investigations aimed at solving such problems of the prior art, and an object of the present invention is to sufficiently deal with deformation such as warpage of a plate-like work. Of course, it is possible to detect the height of the liquid application nozzle, which makes it possible to apply the liquid to the entire area surrounded by the contour line, for example, on a rectangular plate-shaped work without requiring severe machining accuracy. Device and
It is to provide a nozzle height control method using the same.

[0007]

SUMMARY OF THE INVENTION A height detecting device for a liquid application nozzle according to the present invention is provided above a plate-like work, such as a printed circuit board or a glass substrate, which is usually in a rectangular shape, at a predetermined distance from the work. And a nozzle for applying the liquid material to the surface of the work is provided, and at least two, preferably at least a pair of height sensors that are separated by the nozzle are moved integrally with the nozzle. It is provided adjacent to. Here, more preferably, at least a pair of height sensors are arranged point-symmetrically with respect to the center of the nozzle at a position that does not overlap the locus of movement of the nozzle that normally performs translational movement. By the way, as the height sensor here, a sensor using light, a sensor detecting eddy current, or the like can be selected as necessary. Further, the nozzle height control method of the present invention moves the liquid application nozzle integrally with at least two height sensors above the plate-like work, and upon this movement, moves it above the plate-like work. The height of the liquid application nozzle is controlled based on a signal from at least one height sensor located. And other methods are
When all the height sensors protrude to the outside of the plate-like work, suspend the height control of the liquid application nozzle,
The nozzle and the plate-like work are only moved in the horizontal direction.

[0008]

In this type of device, it is not possible to dispose a height sensor either directly above or below the liquid application nozzle, and therefore, in a position adjacent to the nozzle, a height sensor is often several mm.
It is common to dispose height sensors at intervals. Under such circumstances, the apparatus of the present invention is provided with at least two height sensors that move integrally with the liquid application nozzle, and preferably at least a pair of height sensors that are located so as to separate the nozzles. However, even if all the other sensors except
Since the remaining one sensor can sufficiently detect the nozzle height with respect to the plate-like work, when the plate-like work has, for example, a rectangular shape, the liquid application area by the liquid application nozzle is set to the plate. It is possible to enlarge to the contour line position of the workpiece. By the way, in this case,
In the measurement calculation unit, each sensor can be selectively used as necessary only by taking in height data and selecting at least one of the sensors. Therefore, one height sensor is relatively displaced with respect to the nozzle. In comparison with the above, it is not necessary to provide a special actuating mechanism section, and it is possible to realize a compact and lightweight device and a simplified device structure. The device cost can be effectively reduced.

Further, if at least a pair of height sensors are arranged point-symmetrically with respect to the center of the nozzle at a position that does not overlap the locus of movement of the nozzle, then each of the pair of height sensors is It can fully exhibit its original function. In other words, for example, when a pair of height sensors are matched with the movement trajectory of the nozzle, the sensor preceding the nozzle can effectively exhibit its function, but the sensor following the nozzle can Since the height signal of Mn contains most of the influence of the liquid material applied by the nozzle, high measurement accuracy cannot be expected. Moreover, in this case, particularly when the liquid material is applied along the contour line of the plate-like work, one sensor preceding the nozzle moves along the contour line to detect the height. However, it is difficult to obtain high detection accuracy because the contour line portion of the work generally lacks stability in height and flatness.

Further, in the method of the present invention, when the height of the liquid coating nozzle is controlled based on the signal from at least one height sensor, the coating over the entire surface of the plate-like work is controlled with high accuracy. Thus, the application amount, the application shape, etc. at each application portion can be set as desired.

In this method, when all the height sensors are in a state of protruding to the outside of the plate-like work in relation to the number of height sensors to be arranged, the arrangement mode, etc.,
When the height control of the nozzle is interrupted and only the nozzle is moved, the moving distance during the interruption is the distance between the nozzle and the sensor located on the front side in the moving direction thereof.
Since the distance is usually a few mm, it is possible to sufficiently reduce the influence on the coating amount, coating shape, etc. without special control.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a schematic line front view showing an embodiment of the present invention, and FIG. 2 is a schematic line plan view thereof. Here, with respect to the plate-shaped work 1, it is arranged at a predetermined interval above it, and, for example, there, it is moved in the directions of the two-dimensional Cartesian coordinate axes X and Y, and liquid is placed on the surface of the plate-shaped work 1. A nozzle 2 for applying a material is provided, and it moves integrally with the nozzle 2 at a position adjacent to the nozzle 2. In the figure, a pair of two height sensors 3 and 4 are provided on the X-axis and at the center of the nozzle. They are arranged symmetrically with respect to. Further, here, each of the height sensors 3 and 4 is connected to the measurement / calculation unit 5 so that either one of the sensor signals is selectively fetched. Note that, here, three or more height sensors can be arranged, for example, around the center of the nozzle, equidistantly therefrom, and at equal angular intervals, and in the measurement calculation unit 5, two or more height sensors can be provided. It is also possible to take in the sensor signals of, and use the average value of these signals and the calculation results such as the difference as the control signal of the nozzle height. FIG. 3 is a schematic plan view showing another example of the present invention. In this example, a pair of height sensors 3 and 4 are placed at the center of the nozzle 2 at a position where they do not overlap with the nozzle 2 in the normal movement direction of the nozzle 2, that is, in the X-axis direction and the Y-axis direction in the drawing. It is arranged symmetrically with respect to the point. The operation of each device configured as described above will be described below.

FIG. 4 is a schematic plan view showing the maximum coating locus for the plate-shaped work 1 in the apparatus shown in FIGS. 1 and 2. Here, when applying the liquid material on the plate-shaped work 1 having a rectangular contour shape, one of the corners of the plate-shaped work 1 at a point a in the drawing is located on the plate-shaped work 1. It is possible to control the height of the nozzle 2 by detecting the height of the sensor at the peripheral portion of the work 1, and hence the height of the nozzle, by the height sensor 3 of FIG. Proper application of material can be effected, even if the nozzle 2 is moved to point b in the figure under continuous or intermittent application conditions. At this point b, the other height sensor 4 can be made to function, but this sensor 4
When the liquid material is continuously applied from the point a to the point b, the effect of the applied liquid material is included in the height detection signal. Therefore, the detection signal from the sensor 3 is used. By controlling the height of the nozzle, it is possible to perform highly accurate control. Then, when the nozzle 2 reaches the point c which is the corner of the plate-shaped work 1, the sensor 3 protrudes to the outside of the plate-shaped work 1 and the height detection by the sensor 3 becomes impossible. The height of the nozzle 2 is controlled based on the height detection by the sensor 4, assuming that the height of the nozzle 2 is slightly decreased. Therefore, the liquid material can be sufficiently applied to the point c on the corner of the work. afterwards,
During the period from changing the moving direction of the nozzle 2 to the point e via the point d, the sensor 4 is sufficiently stable in height and flatness, which is slightly inside the edge of the plate-shaped work 1. By detecting the height at the part, the height of the nozzle 2 can be controlled with higher accuracy.
It can be applied on the edge of the work. by the way,
The height at the point e is detected by the sensor 4 detecting the height from the edge of the work, and this means that the sensor 4 will detect the height from the work 1 near the point g. It continues until it gets out, and the nozzle 2 has its sensor 4
Based on the detection result of, the liquid material is applied onto the edge of the work. Further, at the point g, the sensor 3 controls the nozzle height based on the detected height from the edge portion of the work, so that the liquid material on the point g, which is the remaining corner of the plate-shaped work 1, is moved. Can be applied, and thereafter, the sensor 3 is used to detect the height of a portion slightly inside the work edge until the nozzle height is returned to the point a through the point h. With higher precision,
The liquid material can be applied to the peripheral edge of the plate-shaped work 1.

Thus, according to such a series of coating steps, the maximum coating locus coincides with the contour line of the plate-like work 1, and the coating area is accordingly larger than that of the prior art shown in FIG. Will be greatly expanded. Although not shown, for the inner part of the maximum coating locus shown in FIG. 4, the height detection signal from at least one of the height sensors 3 and 4 is used, so that any part can be processed as intended. It goes without saying that a liquid material can be applied to. By the way, in the place shown in FIG. 4, particularly when the liquid material is applied to the upper and lower edge portions of the plate-shaped work 1 in the drawing, the control accuracy of the height of the nozzle 2 tends to be insufficient. Is another height sensor located inside the work 1 with respect to each of the upper and lower edges of the plate-like work 1, for example, a height sensor 6 as indicated by virtual lines at points b and f. , 7 can also be provided.

FIG. 5 shows a plate-shaped work 1 of the apparatus shown in FIG.
FIG. 4 is a schematic line plan view showing the maximum coating locus for the. Here, from the point a, which is one interval of the work 1, to the portion near the point c, which is the adjacent corner, the height sensor 3 detects the height of a portion slightly inside the work edge. While controlling the height of the nozzle 2 with high accuracy, the nozzle 2 can be moved to the edge of the work and the liquid material can be applied thereto as expected. When the nozzle 2 reaches the portion near the point c and the sensor 3 protrudes from the edge of the work 1, both the sensors 3 and 4 are located outside the work 1 and the height cannot be detected. Therefore, thereafter, until the nozzle 2 reaches the point c, the liquid material is applied by moving the nozzle 2 while suspending the height control of the nozzle 2. In this case, the nozzle 2
The height control error that may occur is, for example, when the size of the plate-shaped work 1 is 300 × 300 mm,
When the warp per 300 mm in length is about 0.1 mm and the distance between the nozzle 2 and the sensor 3 in the nozzle moving direction is 10 mm, the work that may occur during the movement of the nozzle 2 by 10 mm. Is the amount of warp. It can be expressed as 0.1 × 10/300 = 3.3 (μm), and since this value is extremely small, there is almost no effect on the coating amount etc. even if the height of the nozzle 2 is not controlled. Therefore, the application to the point c is also performed as expected. After that,
By changing the moving direction of the nozzle 2 and controlling the height of the nozzle 2 based on the detection signal from the other height sensor 4, the nozzle 2 moves on the right side of the drawing,
The liquid material can be applied on the edge with high accuracy.

This is almost the same when the liquid material is applied to the lower edge of the figure, and the sensor 4 allows the sensor 4 to move from the edge position until the nozzle 2 reaches the vicinity of the point g. By detecting the height of the inner portion to some extent, the liquid material can be applied on the lower side edge with high accuracy. By the way, also in this case, when the nozzle 2 reaches the portion near the point g, not only the sensor 3 but also the sensor 4 protrudes from the edge of the work 1 to the outside. After the protrusion, the height control of the nozzle 2 is interrupted, and only the coating movement of the nozzle 2 is performed, so that the coating on the point g can be performed with high precision, as described for the point c. .

Further, with respect to the left side of the figure, the height sensor 3 is made to function to control the height of the nozzle 2, so that the height of the nozzle 2 is increased to the edge with high accuracy as expected. A liquid material can be applied.

Therefore, also in this case, the maximum application locus can be made to coincide with the rectangular contour line of the plate-like work 1, and the liquid material can be applied to any part of the work surface with high accuracy. Is possible. In this case, particularly, when it is necessary to further improve the coating accuracy in the vicinity of the points c and g, another pair of height sensors 6, 7 positioned symmetrically with respect to the center of the nozzle. It is preferable to provide the above-mentioned arrangement, which makes it possible to prevent the situation in which all the sensors are exposed to the outside of the work 1 even when applied to any portion of the work 1.

The case where the maximum coating locus is brought about by the action of either one of the sensors with each device has been described above. However, when coating within the area surrounded by the maximum coating locus, both sensors are It is also possible to make 3 and 4 function at the same time and perform height control based on the average value, difference, etc. of the measured values.

[0020]

As described above, according to the present invention, by detecting the height of the nozzle with respect to the plate-like work under the action of the height sensor, it is possible to sufficiently cope with the deformation such as the warp of the plate-like work. Further, by properly using a plurality of sensors provided, it becomes possible to apply the liquid material to all parts of the plate-like work having a rectangular shape, for example. Further, the proper use of the sensor here is performed by selecting the sensor in the measurement calculation unit, so that an operating mechanism having a characteristic is unnecessary as compared with the conventional technology in which one height sensor position is relatively displaced with respect to the nozzle. In addition, the size and weight of the device can be reduced, and the manufacturing can be simplified, and it is possible to completely eliminate the requirement of strict machining accuracy for the operating mechanism. Further, here, when at least a pair of height sensors are arranged point-symmetrically with respect to the center of the nozzle at a position that does not overlap the locus of movement of the nozzle, the detection accuracy of each sensor can be sufficiently improved. Also, when all of the height sensors protrude to the outside of the plate-like work, when the height control of the nozzle is interrupted and only that nozzle is moved, it has almost no effect on the coating accuracy. It is possible to minimize the number of nozzles to be installed without affecting the above.

[Brief description of drawings]

FIG. 1 is a schematic front view illustrating an invention device.

FIG. 2 is a schematic line plan view of FIG.

FIG. 3 is a schematic line plan view illustrating another device.

FIG. 4 is a schematic plan view showing the maximum coating locus of the apparatus shown in FIGS.

5 is a schematic plan view showing the maximum coating locus of the apparatus shown in FIG.

FIG. 6 is a schematic line plan view showing a maximum coating locus of a conventional device.

[Explanation of symbols]

 1 Plate Work 2 Nozzle 3, 4 Height Sensor 5 Measurement / Calculation Unit

Claims (4)

[Claims] 1. A nozzle which is moved on a plate-like work at a predetermined interval from the plate-like work and applies a liquid material to the surface of the work, and a nozzle which is arranged adjacent to the nozzle and moves integrally with the nozzle. At least two height sensors,
A device for detecting the height of a liquid application nozzle. 2. The height detection device according to claim 1, wherein at least a pair of height sensors are arranged point-symmetrically with respect to the center of the nozzle, at a position that does not overlap the movement trajectory of the nozzle. 3. A liquid application nozzle is moved integrally with a plurality of height sensors on a plate-like work, and liquid application is performed based on a signal from at least one height sensor located above the plate-like work. A method for controlling the height of a liquid application nozzle, which comprises controlling the height of the nozzle. 4. A liquid application nozzle is moved integrally with a plurality of height sensors on a plate-like work, and liquid application is performed based on a signal from at least one height sensor located above the plate-like work. In addition to controlling the height of the nozzle, when all the height sensors project outside the plate-like work, the height control of the liquid application nozzle is interrupted and the nozzle and plate-like work are moved horizontally. A method for controlling the height of a liquid application nozzle, which is characterized by performing only movement.