JP3339213B2 - Electronic component mounting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component mounting apparatus which reads image data of each line by a line sensor and prevents unevenness in luminance of an image.

[0002]

2. Description of the Related Art In an electronic component mounting apparatus, a technology has been proposed in which an image of an electronic component is captured by using a line sensor to correct a positional deviation or the like (Japanese Patent Application Laid-Open No. HEI 1-1990).
-183897).

[0003]

However, in this case, while the mounting head holding the electronic component moves a unit distance on the reading head, the data of the image of one line in which the electric charge is accumulated in the line sensor is stored. Has been developed in the direction of movement of the mounting head to form an entire image of the electronic component.

[0004] The time required for the mounting head to move a unit distance is not constant due to unevenness in the movement accuracy of the moving device and other circumstances. For this reason, the light receiving time differs for each line, and even when reading the same part of the electronic component, the luminance is not constant due to the variation in the light receiving time. Here, the recognition processing in the electronic component mounting apparatus is performed based on an image in which data for each line is developed in the moving direction of the mounting head. Therefore, in the conventional electronic component mounting apparatus, there is a problem that uneven luminance is generated for each line in the developed image data, and a recognition error is likely to occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electronic component mounting apparatus capable of eliminating luminance unevenness for each line and suppressing recognition errors.

[0006]

An electronic component mounting apparatus according to the present invention comprises a mounting head for mounting an electronic component on an object, a moving device for moving the mounting head between a parts feeder and the object, and a plurality of devices. It has a line sensor in which the photosensitive elements are arranged in a line, and a read head arranged so that the line sensor intersects the movement path of the electronic component, and a read head is attached to the mounting head every time the mounting head moves a unit distance. The data of the image of the held electronic component is taken in from the reading head for each line and stored, and the measurement time obtained by measuring the time required for the mounting head to move a unit distance and a predetermined reference. based on time, it has a control unit for correcting the data of the image of the electronic component of each line, the image of each line
To the two-dimensional image developed in the transfer direction of the mounting head.
The brightness unevenness is eliminated .

[0007]

According to the above arrangement, the image data for each line is corrected based on the time required for the unit distance mounting head to move. Therefore, high-speed image formation can be performed while eliminating uneven brightness in a two-dimensional image in which the image of each line is developed in the moving direction of the mounting head, and recognition errors in the recognition processing can be suppressed.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an electronic component mounting apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an electronic component to be mounted on a substrate 4 which is picked up from a parts feeder 2 by a nozzle 6 provided below the mounting head 5 and is positioned by a substrate positioning unit 3; A screw shaft rotatably supported along the movement path, 9 is a servomotor for rotating the screw shaft 7, and 10 detects the rotation state of the servomotor 9 to output current position information of the mounting head 5. The encoder 11 has a line sensor in which a number of photosensitive elements are arranged in a line, and the line sensor is disposed so as to be orthogonal to the moving method of the mounting head 5 (axial direction of the screw shaft 7). A reading head 12 for obtaining a line-shaped image of the electronic component 1 passing therethrough, and a light emitting body 12 arranged beside the reading head 11 and illuminating the electronic component 1 with light. Then, the current position information of the encoder 10 and the output of the reading head 11 are output to the control unit 20 described below. The servo motor 9 and the screw shaft 7 correspond to the moving device in the present embodiment.

The control unit 20 includes a screen trigger counter 21
Is provided. The screen trigger counter 21 is connected to the encoder 10. The screen trigger counter 21 is cleared each time the mounting head 5 reaches the substrate 4, and counts the pulses generated by the encoder 10 as the mounting head 5 moves. The count of the screen trigger counter 21 is input to the comparator 22 and compared with the set count set in the screen trigger counter presetter 23. The set count number of the screen trigger counter presetter 23 represents the distance from the parts feeder 2 to the light emission start position set on the parts feeder 2 side from the reading head 11 by the number of pulses, and controls the whole.
It is set before the mounting operation is performed by the arithmetic unit 13 that performs image processing. The comparator 22 outputs a screen trigger signal when the set count of the screen trigger counter presetter 23 matches the count of the screen trigger counter 21. This screen trigger signal is supplied to the reading head 11 via the OR circuit 24, and at the same time, a controller 25 for controlling the light emission of the light emitter 12 as a lighting command signal.
And the luminous body 12 starts emitting light. On the other hand, in accordance with the screen trigger signal, the read data for one line from the read head 11 passes through a correction processing system described later,
Is stored in the image memory provided in the RAM.

The control unit 20 includes a line trigger counter 2
6 is provided, counts pulse signals generated by the encoder 10, and outputs the pulse signals to the comparator 27. The comparator 27 compares the count number of the line trigger counter 26 with the set count number input from the line trigger counter presetter 28. The set count of the line trigger counter presetter 28 indicates the unit movement distance of the mounting head 5 by the number of pulses, and the comparator 27 matches the count of the line trigger counter 26 with the set count of the line trigger counter presetter 28. At this time, an instruction signal for reading one line of read data is output to the OR circuit 24. This comparator 27
, A screen trigger signal is input, and the operation is started according to the input.

The line trigger counter 26 is cleared each time a fetch command signal is issued. Therefore, the capture command signal is issued each time the mounting head 5 moves by a unit distance, and the image of the electronic component 1 is read at equal intervals by one line in the moving direction. When the component 1 has passed, data of the entire image of the electronic component 1 passes through the correction processing system and is stored in the image memory of the arithmetic unit 13. In this manner, a two-dimensional image of the electronic component 1 is obtained by the linear reading by the reading head 11 and the movement of the mounting head 5. While the mounting head 5 moves from the parts feeder 2 to the substrate 4, the screen trigger counter 21 performs counting, and the count is also supplied to a comparator 29 different from the comparator 22. Comparator 29 is a screen trigger counter 2
The count number of 1 is compared with the set count number set in the light-off trigger counter presetter 30. This set count is read from the parts feeder 2 to the read head 1
The distance from 1 to the light emission end position set on the substrate 4 side is represented by the number of pulse signals. When the count value matches the count value of the screen trigger counter 21, the turn-off command signal is output from the controller 25 and the line trigger counter 26. Output to the comparator 27. Thereby, the light emitting body 12 is turned off, and the operation of the comparator 27 stops.

Next, a description will be given of a correction processing system involved while image data output line by line from the reading head 11 is stored in the RAM of the arithmetic unit 13. 31 is a clock for generating a clock signal of a sufficiently high frequency, 32
Is a counter for inputting the clock signal of the clock 31 and the capture command signal of the OR circuit 24, and the counter 32 counts the number of clock signals input from the immediately preceding capture command signal to the next capture signal (that is, the capture signal). (This is the time required for the mounting head 5 to move a unit distance), and outputs the counted value to the correction circuit 33 as the measured time DTc. The counter 32 has a measurement time DT
At the same time as outputting c, a reset signal for resetting its own count value is output.

On the other hand, image data for each line output from the reading head 11 is temporarily stored in a line buffer 34 and output to a correction circuit 33 as raw data Pi.

The correction circuit 33 performs the following correction processing and outputs the corrected data Pci to the arithmetic unit 13.
Here, a predetermined reference time DT0 is set in advance in the correction circuit 33 by the arithmetic unit 13 as an average time required for the mounting head 5 to move by a unit distance.

The correction circuit 33 calculates Pci = (DT0
/ DTc) * Pi outputs the corrected data Pci. That is, the measurement time DTc is not constant due to the operation accuracy of the servomotor 9 and the like, and the light receiving time of the line sensor of the reading head 11 varies from line to line as described in the related art section. The data is output to the arithmetic unit 13 after correcting the variation in luminance for each line. This makes it possible to eliminate variations in luminance for each line when an image is developed two-dimensionally, thereby suppressing errors in recognition processing. In this correction process, if the measurement time DTc is shorter than the reference time DT0, the raw data Pi is enlarged and output, and if longer, the raw data Pi is reduced and output.

[0017]

According to the electronic component mounting apparatus of the present invention, it is possible to eliminate luminance unevenness in a two-dimensional image obtained by developing an image for each line, thereby suppressing a recognition error in the recognition processing.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic component mounting apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component 2 Parts feeder 4 Substrate 5 Mounting head 11 Reading head 20 Control part

Claims (1)

(57) [Claims] 1. A mounting head for mounting an electronic component on an object, a moving device for moving the mounting head between a parts feeder and the object, and a line sensor in which a number of photosensitive elements are arranged in a line. A read head disposed so that the line sensor intersects the movement path of the electronic component; and data of an image of the electronic component held by the mount head every time the mount head moves the read head by a unit distance. From the read head for each line and memorize them,
The time required for the mounting head to move a unit distance is measured.
From measurement and measurement time obtained by a predetermined reference time, it has a control unit for correcting the data of the image of the electronic component of each line, the transfer direction of the mounting head an image of each line
To eliminate uneven brightness in 2D images
Electronic component mounting apparatus is characterized in that the.