SU1406605A1 - Device for checking printed circuit-board for flaws - Google Patents

Abstract

The invention relates to computing and can be used to control information from a printed circuit board. The aim of the invention is to increase equipment utilization and reliability of information. The device allows using the optical splitter 8 to create the required number of rays to illuminate the elements of the surface of the printed circuit board 4, which is moved by the coordinate table 3 under the control of the device.

Description

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The 5 control of the coordinate table, the Alalie of information from the elements of the printed circuit board, obtained by means of the light flux-to-electrical conversion nodes 9 and the corresponding ADC 10, is performed using the comparison unit 12, the memory

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The invention relates to automation and computing and can be used to control information from a photomask, a printed circuit board at various stages of its manufacture.

The aim of the invention is to increase equipment utilization and increase reliability.

Figure 1 shows the block diagram of the proposed device; Fig. 2 is a block diagram of a control unit for the coordinate table; in fig. 3 is a block synchronization diagram.

The device contains a radiation source 1, a readiness signer 2, a coordinate table 3, a controlled printed circuit board 4, a coordinate table control unit 5, a recording unit 6, an indication unit 7, an optical splitter 8, a group of nodes 9 converting light into an electrical signal, an analog group -digital converters (ADC) 10, synchronization unit 11, comparison unit 12, source data memory 13, reference value register unit 14, arithmetic unit group 15. Block 5 contains pulse shapers 16 and 17, And 1 elements 8 and 19, counters 20 and 21 steps, decryption node 22, element NOT 23

Block 11 contains a trigger 24, a pulse generator 25, a start node 26, a 2H-1L 1H 27 element, a row number counter 28, a decoder 29, a pulse shaper 30, And 31-33 elements, a shaper 34 pulses, a delay element 35.

The device operates as follows:

Controlled printed circuit board 4 is installed on the coordinates) 1st table

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13 source data, block 14 of reference value registers, arithmetic blocks 15 "Synchronization of the blocks of the device is carried out by block 11, which in each cycle is controlled by the signal of the former 2. 1 3 gffly, 3 sludge.

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3 to the initial position. The light beam from the radiation source 1, falling on the optical splitter 8, is divided into p rays focused on the surface of the printed circuit board 4. The mutual orientation of the splitter 8 and the PCB 4 is such that the light spots from the beams are located along a straight line along one of the directions, e.g., y, the table movement at an equal distance from each other. Moreover, the light spots of the first and second rays fall on the technological sections of the printed circuit board 4, respectively, on the fouls y and the base.

The control table control unit 5 allows the printed circuit board 4 to be moved in an automatic mode, generating driving control pulses in the directions x and y. The node 26 of the synchronization unit 11 includes a generator 25, the pulses of which are fed to the first inputs of the elements H 18 and 19 of the table control unit 5 Depending on the state of the node 22, the pulses are fed to the element 20 steps x or the counter 21 steps y . At the same time, these pulses are fed to the formers 16 and 17 of the pulses, generating signals for moving the coordinate table 3. The decoder of the state of counters 20 and 21 also controls the reverse of the motors of the coordinate table 3. Thus, the scanning field of the printed circuit board 4 is formed, which consists of segments, scanned by individual rays. The size of the segments is chosen from the condition of overlap u, x at the width of one line at the end of 1.: scan,

The rays reflected from the surface of the printed circuit board 4 fall on the nodes 9, which convert the luminance signals into an electrical signal. The output voltages of the nodes 9 are converted into a digital code using the ADC 10, these ADCs are triggered by signals of their readiness coming to the inputs of the driver 2, the voltage level of which, corresponding to the availability of all the ADCs 10, goes to block II.

The first run of the A / D converter 10 is made from the node whose pulse arrives at the input of the element 27, and if there is a ready signal at the other input of this element, a pulse is generated at its output that triggers the driver 30.

The output pulse of the imaging unit 30 is supplied to the start of the ADC 10. Subsequent launches are carried out from the pulses produced by the comparing12 comparison and the memory 13 during the passage of the rays along the last rows.

All information obtained by scanning the surface of the printed circuit board A from the outputs of the A / D converter 10 is fed to the corresponding inputs of the blocks 15, where a comparison is made with the average reference value. The average value is determined using the adder of block 15, the inputs of which are supplied with reference values from block 14, and the output is half the sum of these

15 values, without using the least significant bit of the result, which is equivalent to dividing by 2, rounded to the whole. Comparison of current values of information with reference produced

2Q by the programmable logic matrix of block 15, at the output of which logical O is present, in the case when the current value is less than the reference one, and logical 1 in the case when the notebook has 16 displacement signals, the incoming value is equal to or greater than the support elements 27.

The readiness signal of the A / D converter 10, received after the first start, is sent to the driver 34, the formations at the moment of the end of the conversions pulse 30 arriving at the first input of the And 33 element, the output of which is fed to the block 14. In the registers of the block 14, the results are recorded by this signal signal conversion p-5 bones of the first and second reflected rays of the respective levels of the foil and the base. At the same time, the pulse of driver 34 is supplied to delay element 35. The delayed impulse transfers the trigger 24 to the state that prohibits the passage of signals through the element 33. The trigger 24 returns to the initial state after the end of the scanning of the printed circuit board 5 and at the signal of the decoder 29 controlled by the counter of 28 lines to the input which receives the reverse pulses from the control unit 5 of the table. Thus, once at the first gQ start of the A / D converter 10, the reference values are fixed. The decoder 29 also controls the passage of motion pulses by means of elements AND 31 for recording information received in memory 13 received during the passage of the beams along the first lines of the corresponding segments of the printed circuit board 4 and elements 32 for controlling the operation of the unit

Claims (1)

foot. Information from the outputs of the blocks 15 enters the registration unit 6, which is an accumulation device, for example, a magnetic disk, to the inputs of the memory 13, except for information from the output of the block 15 corresponding to the first beam, and to the inputs of the comparison unit 12, except for information from the output block 15, corresponding to the last n beam. From the recording signals from synchronization block 11 to memory 13, the information corresponding to the first lines is recorded, and from the control signals from synchronization block 11, information from memory 13 is compared in block 12 comparison with information s, corresponding to the last line. Moreover, a comparison is made between the information from the last line of the PCB segment 4 and the information from the first line of the next segment. The result of the comparison with the output of the comparison unit 12 is supplied to the display unit 7, which indicates the fact of the end of the scan. The full coincidence of the compared volumes of information indicates the completion of control of information from the surface of the printed circuit board 4 in each segment and the entire surface with overlap between the segments with a width of one line. Claims 1. A device for monitoring defects in a printed circuit board, comprising a comparison source 12 and a memory 13 during the passage of the beams along the last lines. All information obtained by scanning the surface of the printed circuit board A from the outputs of the A / D converter 10 is fed to the corresponding inputs of the blocks 15, where a comparison is made with the average reference value. The average value is determined using the adder of block 15, the inputs of which are supplied with reference values from block 14, and the output is half the sum of these 5 values, without using the least significant bit of the result, which is equivalent to dividing by 2, rounded to the whole. Comparison of current values of information with reference produced Q is a programmable logical matrix of block 15, at the output of which logical O is present, in the case when the current value is less than the reference one, and logical 1 in the case when the current value is equal to or greater than the supports foot. Information from the outputs of the blocks 15 enters the registration unit 6, which is an accumulation device, for example, a magnetic disk, to the inputs of the memory 13, except for information from the output of the block 15 corresponding to the first beam, and to the inputs of the comparison unit 12, except for information from the output of the block 15 corresponding to the last p beam. According to the recording signals from the synchronization block 11, the memory corresponding to the first lines is entered into the memory 13, and the control signals from the synchronization block 11 compare the information from the memory 13 in the comparison block 12 with the information th corresponding to the last line. Moreover, a comparison is made between the information from the last line of the PCB segment 4 and the information from the first line of the next segment. The result of the comparison with the output of the comparison unit 12 is supplied to the display unit 7, which indicates the fact of the end of the scan. The full coincidence of the compared volumes of information indicates the completion of control of information from the surface of the printed circuit board 4 in each segment and the entire surface with overlap between the segments with a width of one line. Claim 1. Device for monitoring printed circuit board defects, containing a radiation source, a coordinate table, a control table for the coordinate table, a recording unit, a display unit, a unit for converting light flux into an electrical signal, an analog-to-digital converter, a readiness sign driver, characterized in that , in order to increase equipment utilization and increase reliability, an optical splitter, additional nodes converting light flux into electric A common signal, additionally analog-digital converters, a block of reference value registers, a group of arithmetic blocks, a source data memory, a comparison block, a synchronization block, the output of the radiation source through an optical splitter optically connected to the surface elements of the controlled printed circuit board connected by the optical inputs of nodes converting a light flux into an electrical signal of a group, the outputs of which are connected to the information inputs of the corresponding analog-to-digital converters The outputs, whose information outputs are connected to the information inputs of arithmetic blocks, the outputs of which are connected to the information inputs of the registration unit, the source data memory and the first group of information inputs of the comparison unit, the output of which is connected to the input of the display unit, the readiness outputs of the analog-digital converters of the group are connected to the inputs of the generator of the sign of readiness, the output of which is connected to the input of the sign of readiness of the synchronization unit, the output synchronization input of information which Inen with the information output of analog-to-digital converters of the group, the clock output of the synchronization unit is connected to the clock inputs of the registration unit and the coordinate control unit 66056 table, the group of control outputs of the coordinate table of which is connected to the control inputs of the coordinate table, and the group of control synchronization outputs is connected to the control inputs of the synchronization unit, the synchronization outputs of which are connected to the synchronization inputs 10 blocks of reference value registers, comparison block and source data memory, the outputs of which are connected to the second group of information inputs of the comparison block, information outputs of the first and second analog-digital converters of the group are connected to the first and second information inputs of the block of reference value registers outputs data of the upper and lower 20 levels of luminance of which are connected to the data inputs of all the arithmetic units of the group. 2 ,. The device according to claim 1, wherein the control table of the coordinate table contains two step counters, a decryption node, two pulse shapers, two AND elements, an NOT element, and the clock input of the block is connected to the first inputs of the first and second elements And, the outputs of the step counters are connected to the inputs of the decryption node, the first output of which is connected to the second input of the first element AND and through the element NOT to the second input of the second element And, the output of the first element And is connected to the inputs of the first step counter and pulse generator, the output of the second element I is connected to the inputs of the second step counter and the pulse generator, the outputs of the first and second pulse formers and the second output of the decryption node are the output group of the control of the coordinate table of the unit, the output of the first pulse forcing and the second output of the synchronization control. 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