JPH0467696A - direct drawing device - Google Patents

Abstract

PURPOSE:To enable a drawing device to be kept always high in drawing quality by a method wherein position data obtained by counting pulses transmitted from encoders mounted on motors which drive an XY table are stored in a memory, height data are read out from the stored data at drawing to control the height of a nozzle. CONSTITUTION:Pulse motors are made to serve as an X direction motor 18, a Y direction motor 19, and a Z direction motor 3. Encoder pulses EPx and EPy transmitted from encoders 20 and 21 mounted on the motors are inputted into motor drivers 27 and 28. When the height of a ceramic board 12 is measured by a height sensor 16 and drawing is carried out by a nozzle 11, height data are stored in a memory RAM, which are made to serve as indexes when height data are read out. A control unit 22 drives and controls the Z direction motor 3 at drawing basing on the height data stored in the RAM to control the height of the nozzle 11 keeping the distance between the nozzle 11 and the drawing plane of a ceramic board 12 constant.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for discharging a circuit forming paste from a nozzle while moving an object to be drawn, such as a heat-resistant ceramic substrate, relative to a nozzle. The present invention relates to a direct writing device that forms a thick film circuit directly on a drawing body.

[Conventional technology]

After drawing a predetermined circuit by discharging a circuit forming paste onto a heat-resistant ceramic substrate (object to be drawn) such as an alumina substrate using a direct drawing device, this is then fired at a high temperature to form a thick film circuit pattern. is being carried out.

Depending on the type of circuit forming paste (hereinafter referred to as "paste") discharged from the nozzle, thick films of various shapes such as conductors, resistors, and non-conductors can be formed. An electrical circuit is constructed by stacking film layers.

By the way, when drawing with paste on the object to be drawn with such a direct drawing device, the gap between the tip of the nozzle and the surface of the object to be drawn must be controlled to always be kept constant, otherwise the paste ejection resistance will increase. As a result, the ejection amount changes and the drawing quality deteriorates.

Therefore, in conventional direct drawing devices, a height sensor is fixed at a predetermined interval together with a nozzle above an XY child table on which the object to be drawn is placed, and the height sensor is used to detect the object to be drawn in advance. The height of each position in the entire drawing surface is measured, and the height data is stored in a memory in correspondence with the position data of the object to be drawn.

In other words, height data, which is data that changes depending on the unevenness and undulations of the surface of the object to be drawn, can be converted to an arbitrary distance in the XY force direction (
pitch) is stored in memory.

During drawing, the XY child table moves according to the drawing position to move the object to be drawn relative to the nozzle, while reading the height data corresponding to the position of the object from the memory and adjusting the nozzle. The height is controlled and the circuit forming pastes 1 to 1 are discharged from the nozzle to draw on the object to be drawn.

In this way, the gap between the tip of the nozzle and the surface of the object to be drawn can always be kept constant, so that good drawing quality can be maintained.

[Problem to be solved by the invention]

However, in such a conventional direct writing apparatus, when height data is measured for each position of the entire drawing surface of the object to be drawn using the height sensor, and when thick film circuits are formed on the object to be drawn by the nozzle, When forming a
The number of driving pulses applied to each motor (both use pulse motors) that move in the axial direction is counted, and the count value is used as the position data (index) of the object to be drawn, and the measured height data is It managed the storage of height data into memory and the reading of height data from memory.

In this way, if the count value of driving pulses based on the position command given to the motor that moves the XY child table is used as the position data (index) of the object to be drawn, then the position command and the actual position of the XY child table, that is, the position of the object to be drawn, are There is a delay between the position and the position, and this delay (deviation) becomes particularly large at the start and end of movement.

As a result, there will be a discrepancy in the relationship between the height data and its position data, so the measured height data is stored in memory using this position data as an index, and when drawing, the height data is used to count the driving pulses mentioned above. If the height of the nozzle is controlled by reading the value from memory as an index, the nozzle cannot be accurately controlled according to the surface height of the actual drawing position of the object to be drawn, so sufficient drawing quality cannot be obtained. There was a problem.

This invention was made in order to solve the problems with such conventional direct drawing devices, and eliminates the occurrence of discrepancies between the height data described above and the position data that is the index of the measurement point. The purpose is to always obtain sufficient drawing quality in this way.

[Means to solve the problem]

In order to achieve the above object, the present invention applies pulses to a motor that moves slowly in the X-axis direction and a motor that moves quickly in the Y-axis direction of the XY child table by the rotation of each motor shaft in the direct drawing device as described above. The above-mentioned method is used when attaching an encoder that generates data, and when measuring height data for each position of the entire drawing surface of the object to be drawn using a height sensor, and when forming a thick film circuit on the object to be drawn using a nozzle. Means is provided for counting the pulses generated by each encoder and obtaining position data serving as an index for storing the height data in the memory and for reading the height data from the memory.

[For production]

Each encoder attached to each motor that moves in the XY child table xI# direction and the Y axis direction generates a pulse by the rotation of each motor shaft, so each XY child table is moved by the rotation of each motor shaft. A number of pulses are generated corresponding to the actual amount of movement.

Therefore, the position data obtained by counting the pulses generated from each encoder accurately corresponds to the actual height measurement position by the height sensor or the actual drawing position by the nozzle, so this can be used as an index. By storing the measured height data in memory and reading it out from memory during drawing to control the nozzle height, the gap between the nozzle tip and the surface of the object to be drawn can be controlled accurately and constant. It is possible to maintain good drawing quality at all times.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 2 is a perspective view of a mechanical part of a direct drawing apparatus showing an embodiment of the present invention. A support plate 2 is fixed to a frame 1 of the apparatus, and a Z-direction motor 3 is held on the upper part of this support plate 2. It is held by member 4.

The rotating shaft of this two-way motor 3 is connected via a coupling 5 to a ball screw 7 supported by a bearing receiver 6 housing a bearing, and this ball screw 7 is screwed into a nozzle holding member 8. The nozzle holding member 8 is attached to the support plate 2 by a linear slider 9 so as to be able to slide vertically (in the Z-axis direction).

A cylinder 10 integrally equipped with a nozzle 11 is attached to this nozzle holding member 8.
A paste 13 is discharged from a nozzle end 11a onto a ceramic substrate 12, which is an object to be drawn.

At that time, the ceramic substrate 12 is
The XY child table 4 is positioned and placed on the XY child table 4 which is driven in the X and Y directions by a Y stage device, and is placed in the X and Y directions perpendicular to the height direction of the nozzle 11 using a plurality of positioning pins 17. A desired thick film pattern is drawn by the paste discharged from the nozzle end 11a.

Further, a height sensor 16 for measuring the height of the drawing surface of the ceramic substrate 12 using laser light is attached to a holder 15 fixed to the support plate 2 in parallel with the nozzle 11.

FIG. 1 is a block diagram of the control system of this direct writing device, and the control unit 22 is a microcomputer consisting of a CPU as a central processing section, a ROM as a program memory, a RAM as a data memory, and an Ilo as an input/output section. It is made up of.

Then, this control unit 22 causes the electropneumatic converter 24 to control the air pressure from the air source 23 based on the output signal, and also controls the opening and closing of the solenoid valve 25 to supply the required air pressure to the cylinder 10 equipped with the nozzle 11. and cylinder 1
The paste in 0 is discharged from the nozzle end 11a of the nozzle 11.

Moreover, this control unit 22 is connected to the motor driver 2B.
A command signal is output, and the Z direction motor 3 shown in FIG. 2 is driven to control the height (Z direction position) of the nozzle end 11a.

On the other hand, the XY child table 4 on which the ceramic substrate 12 is placed
For an XY stage device equipped with
An X-direction motor 18 for moving in the X-axis direction within a plane orthogonal to the axial direction, and an X-direction motor 19 for moving in the Y-axis direction orthogonal thereto are provided.

And these X direction motor 18 and X direction motor 19
are each equipped with encoders 20 and 21 that generate pulses according to the rotation of each motor shaft.

The control unit 22 outputs an X command signal to the motor driver 27 and a Y command signal to the motor driver 28 to drive and control the X direction motor 18 and the X direction motor 19, thereby controlling the XY child table 4 and the mounted thereon. The placed ceramic substrate 12 can be moved to any position within the XY plane.

Note that it is preferable to use pulse motors as the X-direction motor 18, the Y-direction motor 19, and the above-mentioned Z-direction motor 3.

The encoder pulses EPx and EPy generated by the encoders 20 and 21 are respectively input as position feedback signals to the motor drivers 27 and 28, and are also input to the control unit 22, so that the height sensor 16 controls the drawing surface of the ceramic substrate 12. When measuring the height of the entire area and when drawing with the nozzle 11, the height data is stored in the memory (RA
M) and to obtain position data that serves as an index (address) for reading the height data. The details will be described later.

Note that the drawing surface of the ceramic substrate 12 is quite uneven, although it is on the order of microns, and in some cases, a thick film pattern has already been formed. Fix the height position of 16 and move it to XY
While moving the child table 4 in the X and Y directions, its height sensor 16 sets the measurement pitch for each coordinate position of the entire drawing surface of the ceramic substrate 12 (taking into account the required accuracy and data storage capacity of the memory, etc.) Then, the height data is input to the control unit 22 and stored in the RAM together with the coordinate position data of each measurement point.

Based on the height data stored in the RAM, the control unit 22 controls the movement of the Z-direction motor 3 as described above at the time of drawing, and adjusts the height of the nozzle 11 to the distance from the drawing surface of the ceramic substrate 12. is controlled to keep it constant to prevent the nozzle end 11a from coming into contact with the drawing surface or a previously formed pattern and becoming unable to draw, or from being too far away and causing the line width of the pattern to become thin. .

Further, an operation panel 30 for displaying operations is connected to this control unit 22.

Note that drawing data for moving the XY child table during drawing is sent from an external device (not shown) to this control unit 22.
The drawing data may be input each time, or the necessary drawing data may be stored in the internal RAM in advance.

As the height sensor 16, a triangulation distance sensor using a laser spot light is used.
It is recommended to use a distance sensor as shown in the figure.

This consists of a small, high-output semiconductor laser 41 and a semiconductor device detector (Posit) with high resolution and high-speed response.
ion S sensitive device (hereinafter abbreviated as rPsDJ) 42, a laser beam from a semiconductor laser 41 as a light source is focused by a light projection lens 43, and a target object 45 to be measured is
The reflected light f2 from the target object 45 is focused onto one point on the light receiving surface of the PSD 42 by the light receiving lens 44 disposed at a predetermined distance from the light projecting lens 43. It has a structure that allows it to receive light.

Since the angle θ of the reflected light f2 focused by the light receiving lens 44 changes due to the displacement of the target object 45 in the direction of the arrow, the position of the focused spot on the PSD 42, that is, the light receiving position Displace. This light receiving position X can be easily detected by the PSD 42.

Therefore, if the distance between the optical axes between the light projecting lens 43 and the light receiving lens 44 is d, and the distance between the light receiving lens 44 and the PSD 42 is F, then the distance to the target object 45 can be determined by the following equation.

L=d -F/X Next, the configuration for obtaining XY position data in the control unit 22 of this embodiment and the operations during height measurement and drawing will be explained with reference to FIGS. 4 to 6. .

Inside the control unit 22, as shown in FIG.
X counter 221 and Y counter 222 which are presettable amplifier down counters controlled by 20
and is provided.

The X counter 221 counts encoder pulses EPx from the encoder 20 in FIG. 1 and outputs a borrow signal and a count value Nx indicating the position in the X direction to the CPU 220.

The Y counter 222 counts the encoder pulses EPy from the encoder 21 shown in FIG. 1, and outputs a borrow signal and a count value Ny indicating the position in the Y direction to the CPU 22'O.

Each of these counters 221 and 222 is switched to operate as a down counter by a U/D switching signal from the CPU 220 when measuring height, and corresponds to a measurement pitch that is set in advance to obtain the required accuracy. A certain preset value is preset, and when the encoder pulses are counted by the preset value, a borrow signal is output, and the same value is preset again to prevent miscounting of the encoder pulses.

FIG. 5 is a flow diagram showing the operation of the CPU 220 during this height measurement.

The CPU 220 has an X counter 221 and a Y counter 22.
After presetting the preset values in 2,
When a borrow signal is input from any counter, the first
After taking in the height data from the height sensor 16 shown in the figure and temporarily storing it, it is determined from which counter the borrow signal was input.

As a result, if it is from the X counter 221, the internal X address is incremented and then the X counter 221 is preset; if it is from the Y counter 222, the internal Y address is incremented and then the Y counter 222 is preset.

Then, using the incremented X and Y addresses as addresses (indexes), the temporally stored height data is stored in the RAM 223.

This operation is repeated every time a pollo signal is input from the X counter 221 or the Y counter 222.

At the time of drawing, the X counter 221 and Y counter 222 are reset (preset to "0") and are moved in the direction of the X command and Y command for moving the XY child table 4 in FIG. 1 from the reference position according to the drawing data. Depending on the CPU220
Up/down can be switched by the U/D switching signal from.

Then, as shown in the flowchart of FIG. 6, the CPU 220 receives the count value Nx or Y from the X counter 221.
When the count value Ny from the counter 222 changes, the X and Y count values at that time are captured and temporarily stored, and the RA
It is determined whether there is an address corresponding to the count value in M22'';.

If not, wait for the next count value to change,
If there is, the height data at that address is read from the RAM, and based on it, two commands are output to the motor driver 26 to control the height of the nozzle 11. Repeat this operation until the drawing is finished.

In this way, during height measurement and drawing, there is almost no discrepancy between the actual position of the ceramic substrate 12, which is the object to be drawn, and the position data (address) in the X and Y directions determined by the control unit 22. Therefore, the height of the nozzle 11 can be accurately controlled according to the uneven state of the drawing surface, and the drawing quality is improved.

Note that since the drawing point by the nozzle 11 and the measurement point by the height sensor 16 have a fixed interval (offset) in the X direction, this Correct the position data (address) in the X direction by the offset.

Also, during drawing, not only when reading height data,
It is desirable to perform data interpolation even during this period to control the height of the nozzle 11.

Furthermore, the X counter 221 and Y counter 22 in FIG.
2 can also be a software counter based on program processing by the CPU 220.

〔Effect of the invention〕

As described above, the direct writing apparatus according to the present invention uses a height sensor to measure height data for each position over the entire drawing surface of an object to be drawn, and a nozzle to form a thick film circuit on the object to be drawn. When forming, the encoder attached to each motor that moves in the X-axis and Y-axis directions of the XY child table on which the object is placed counts the pulses generated, and the measured height data is stored in memory. Since the position data that serves as an index for storing and reading the height data from the memory is obtained, there is almost no discrepancy between the actual position of the object to be drawn and the position data that serves as the index. The height of the nozzle can be precisely controlled according to the uneven state of the drawing surface, improving the drawing quality.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram of a control system of a direct writing device showing an embodiment of the present invention, Fig. 2 is a perspective view showing the external appearance of the mechanism, and Fig. 3 is a height diagram used in this embodiment. An explanatory diagram showing an example of a sensor. FIG. 4 is a block diagram showing the configuration of parts directly related to the present invention in the control unit 22 shown in FIG. 1, and FIG. 5 is a flow diagram showing the operation of the CPU 220 shown in FIG. 4 during height measurement. is a flowchart showing the operation during drawing as well. 2...Support plate ro・Z direction motor 10・
... Cylinder 11 ... Nozzle 12 ... Ceramic substrate (object to be drawn) 13 ... - Paste 1
4...XY child table 5...Holder 16.
- Height sensor 17... Positioning pin 18...・・X counter 222 ・・Y counter 22
3...RAM (memory) 21...Encoder Fig. 1 Fig. 2 ρ Fig. 3 Fig. 4 Fig. 5 Fig. 6

Claims (1)

[Claims] 1. An XY table on which an object to be drawn is placed, and a nozzle and a height sensor fixed above the table at a predetermined interval,
While moving the object to be drawn relative to the nozzle by driving the XY table based on height data for each position of the entire drawing surface of the object measured in advance by the height sensor. A direct writing apparatus that controls the height of the nozzle and discharges a circuit forming paste from the nozzle to form a thick film circuit on the object to be drawn, comprising: a motor that drives the XY table in the X-axis direction; An encoder that generates pulses as each motor shaft rotates is attached to each motor that drives in the axial direction, and the height sensor measures height data for each position on the entire drawing surface of the object to be drawn. When forming a thick film circuit on the object to be drawn using the nozzle, the pulses generated by each of the encoders are counted, and the height data is stored in a memory and the height data is What is claimed is: 1. A direct drawing device comprising: means for obtaining position data serving as an index for reading out data from a memory.