JPH0115083B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a substrate hole position detection device that converts projected light from a substrate hole into a voltage using a light receiving element and detects the substrate hole position from the output voltage. Detecting the position of a hole in a substrate using a four-part light receiving element has been practiced for some time. An example of the conventional device is shown in FIG. In the figure, the light emitted from floodlight 1 is XY
Pass through hole 2 of the board placed on table 3,
This corresponds to the four-divided light receiving element 4. The 4-split light receiving element 4 is
It has four light-receiving elements divided into four by lines parallel to the axis and the Y-axis, and each light-receiving element outputs a voltage proportional to the amount of irradiated light through lines 5a to 5d. Voltages proportional to the amount of light transmitted through the lines 5a to 5d are applied to buffer amplifiers 6a to 6, respectively.
d. Assuming that the outputs of the buffer amplifiers 6a to 6d are _V1 to _V4 , the outputs _V1 and V4 are sent to the adder 17a made of an operational amplifier, and the outputs V2 and _V4 are sent to an adder _17a made of an operational amplifier.
V ₃ is sent to adder 17b, and outputs V ₁ and V ₂ are sent to adder 17b.
c, and outputs V ₃ and V ₄ are respectively input to an adder 17d. Next, the outputs of the adders 17a and 17b are input to the subtracter 18a, and the subtracter 18a outputs a signal _ΔVX of (V ₁ +V ₄ )−(V ₂ +V ₃ ). On the other hand, the outputs of the adders 17c and 17d are input to the subtracter 18d, and from the subtracter 18b (V ₁
A signal ΔV _Y of +V ₂ )−(V ₃ +V ₄ ) is output. The output of the subtracter 18a enters a comparator 19a and is compared with a comparison voltage 20a, and when the output of the subtracter 18a is greater than the comparison voltage 20a, an H level signal is output from the comparator 19a.
This causes the controller 21 to
The driver 22 outputs a signal to the XY table 3.
Move slightly in the X direction. As a result, if the output ΔV _X of the subtracter 18a becomes smaller than the comparison voltage 20a,
The output of the comparator 19a becomes L level,
Adjustment of the XY table 3 is stopped. X at this time
The position of the hole currently being inspected in the X direction can be determined by the amount of directional movement, and the position of the hole in the Y direction can be detected by similarly adjusting the Y direction. Since conventional devices employ the method described above, they have had the following various drawbacks. That is,
In order to obtain the same detection accuracy for substrate holes of different sizes, it was necessary to change the comparison voltages 20a and 20b each time. Furthermore, if the substrate hole is completely off the light receiving element, the four output voltages from the four-part light receiving element 4 will be the same, which may cause a malfunction such as incorrect hole position detection. Furthermore, comparator circuits 19a and 19b
With a hand, it was only possible to know whether the board hole position was correct or misaligned, but not the amount of deviation in the hole position. Therefore, the XY table had to be moved one pulse at a time to search for the hole position, which took a long time to detect. It cost. The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, to be able to detect the hole position with high precision regardless of the size of the board hole, and to prevent malfunctions even if the board hole is completely removed from the light receiving element. First, it is an object of the present invention to provide a hole position detection device that can search for hole positions at high speed. The present invention A/D converts four output voltages from four-divided light-receiving elements corresponding to substrate hole positions,
The above object is achieved by importing the converted value into a computer and converting the amount of deviation in the X and Y directions into the amount of movement of the board to detect the position of the hole in the board. It has characteristics. Examples will be described below with reference to the drawings. FIG. 2 shows an embodiment of the invention. In the figure, 7 is a multiplexer, 8 is an analog signal, 9 is a sample and hold circuit, 10 is a hold signal, and 11 is an A/
D converter, 12 is a digital signal, 13 is a computer, 14 is an XY table drive signal, 15 is a hold instruction signal, 16 is an A/D converter conversion start signal, 17 is a channel switching signal, 18 is a hole diameter setting means, Other symbols indicate the same things as in FIG. Next, the operation of this embodiment will be explained. Light from the light projector 1 passes through the board hole 2 and is irradiated onto the four-part light receiving element 4 . The four-division light-receiving element 4 generates detector output voltages on lines 5a to 5d in proportion to the amount of light received by each portion. This output voltage is input to a multiplexer 7 via buffer amplifiers 6a to 6d. The detector output voltages V ₁ -V ₄ input to the multiplexer 7 are processed by the operation of the computer 13 as shown in the flowchart of FIG. First, the computer 13 determines whether a four-channel switching signal has been sent to the multiplexer 7 (step S1), and if no, the process advances to step S2. In step S2, the computer 13 sends the channel switching signal 16 to the multiplexer 7, and first the buffer amplifier 6a and the sample hold circuit 9
Connect. Next, when the hold instruction signal 15 is sent to the sample and hold circuit 9 (step S3), the analog signal 8 is sampled and held. The held signal 10 is the A/D converter conversion start signal 16
is input to the A/D converter 11 (step S4) and converted into a digital signal 12. This digital signal is stored in the computer (step S5). In this procedure, the multiplexer switches the buffer amplifiers 6a, 6b, 6 by the channel switching signal 17.
c and 6d are sequentially connected to the sample and hold circuit 9, and this is carried out cyclically until all four channels of A/D converted hold signals are taken into the computer. Hold signals for 4 channels are sent to computer 1.
3, step S1 becomes YES and the process proceeds to step S6. In step S6, it is determined whether the hold signals of the four channels stored in the computer 13 are all 0. If all are 0, proceed to step S7, output a detection error,
finish. Thereafter, the setting of the board is re-arranged, and the process returns to step S1 again. Then, the procedure from step S1 to step S6 is executed again. If it is determined in step S6 that all of the hold signals of the four channels are not 0, the process advances to step S8. In step S8, the difference in the X-axis direction (shift amount)
ΔV _X is calculated by the following formula. _{ΔV _ _ _ _ _} ΔV _Y =(V ₁ +V ₂ )−(V ₃ +V ₄ ) Next, it is determined whether the difference ΔV _X in the X-axis direction and the difference ΔV _Y in the Y-axis direction are 0 (step S1).
0), if not 0, these deviation amounts ΔV _X and ΔV _Y are
Converted to the amount of movement of the XY table (step S
11). To convert this amount of deviation into the amount of movement of the XY table, proceed as follows. In the computer, the amount of movement (μm) of the XY table in the X and Y directions corresponding to the amount of deviation (mV) in the X and Y directions as shown in Table 1 is calculated in advance for each hole diameter. Enter the data. Then, the amount of movement of the XY table is calculated from the amount of deviation found in steps S8 and S9 and the diameter of the hole.

[Table] Note that this amount of movement is one movement, and the distance between board hole 2
This is the distance necessary to bring the light on the line connecting the light projector 1 and the center of the four-part light receiving element 4. For this reason, even if the amount of deviation is large, the corresponding amount of movement can be retrieved from the table in Table 1, and that amount of movement can be used.
By operating the XY table, board hole positions can be determined in one operation. Note that Table 1 schematically shows data stored in the memory within the computer 13. Here, an example of a functional block diagram of the movement amount calculation means in the computer 13 will be explained with reference to FIG.
When the detected output voltages V ₁ to V ₄ for four channels are taken into the computer, the V ₁ to _{V 4} all-0 determining means 21 determines whether the hold signals of the four channels are all zero. If all are 0, the selection stage 22 selects the detection error output means 23 and activates it. On the other hand, if even one of the hold signals of the four channels is not 0, _ΔV
The calculation means 24 and the ΔV _Y calculation means 26 are activated. The outputs _of the _ΔV and the level is
It becomes one element of the ROM29 address. Further, data from the hole diameter setting means 18 is also stored in the ROM.
29 and becomes one element of the address. The ROM 29 uses the signals from the level determining means 25, 27 and the hole diameter setting means 18 as addresses, and outputs movement amount data in the X direction and the Y direction. This movement amount data is sent to the driver 22. When the amount of movement of the XY table is determined, the amount of movement is output to the XY table (step S12).
Then, the process returns to step S1 and the aforementioned procedure is performed again. Then, when the differences ΔV _X and ΔV _Y between the X and Y axes both become 0 in step S10, the operation ends. In addition, if you add the movement amount data for the deviation amount obtained by this operation to the data in Table 1 above, or correct the movement amount data in Table 1 using the above movement amount data, That is, by performing a learning operation, the data in Table 1 can be enriched and improved. As described above, according to the present invention, a constant detection accuracy can be obtained regardless of the size of the substrate hole, and malfunction will not occur even if the substrate hole is completely displaced from the 4-division light receiving element. Furthermore, since the amount of deviation is recognized and converted to the amount of movement of the XY table, the board hole position can be detected with a single operation of the XY table. Therefore, the hole position can be detected at high speed.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a hole position detection device using a conventional OP amplifier, Fig. 2 is a block diagram showing an embodiment of the hole position detection device according to the present invention, and Fig.
FIG. 4 is a flowchart for explaining the operation of the computer shown in FIG. 4, and FIG. 4 shows a functional block diagram of the movement amount calculation means in the computer. 1... Floodlight, 2... Board hole, 3... XY table,
4... Quadrant light receiving element, 6a to 6d... Buffer amplifier, 7... Multiplexer, 9... Sample hold circuit, 11... A/D converter, 13... Computer, 14... XY table drive signal, 15... Hold instruction signal, 16... A /D converter conversion start signal, 17...channel switching signal.

Claims (1)

[Claims] 1. In a hole position detection device that detects the position of a hole in a substrate using a four-division light receiving element divided into four areas of the first to fourth quadrants along the X-axis and Y-axis, the four A split light receiving element,
an A/D conversion circuit that A/D converts four analog voltages (V ₁ , V ₂ , V ₃ , V ₄ ) output from the first to fourth quadrants of the four-division light receiving element; The signal digitized by the conversion circuit (V ₁ ′,
V ₂ ′, V ₃ ′, V ₄ ′) and ΔV _X = (V ₁ ′+V ₄ ′)−
(V ₂ ′+V ₃ ′), ΔV _Y = (V ₁ ′+V ₂ ′)−(V ₃ ′+V ₄ ′
), the deviation _{amounts ΔV} A substrate hole position detection device characterized by comprising an XY table driver.