DE1900298A1 - Method and device for testing printed circuits having electronic components - Google Patents

Description

Description of the patent application of the company Engins Matra SA, * + 9, rue de Lisbonne, Paris ^8e, France

concerning

Method and device for testing printed circuits having electronic components

So far, the testing of electronic components has been done Circuits, such as a plate, in that this plate is operated under conditions analogous to the operating conditions and it is checked whether the values of the electrical factors at the outputs of the plate correspond to the nominal values.

If an anomaly is found, it is impossible to pinpoint the exact origin of the anomaly discarded as scrap, which is, however, economically unsatisfactory because of the relatively high price of a finished panel, or the plate is subjected to a more detailed analysis, which is very difficult because the electronic components on the Plate become ever smaller and more numerous, so that these Analysis is extremely lengthy and complicated and in any case involves a highly skilled manual labor that makes the price the plates increased significantly.

009823/1102

The invention has for its object to provide having printed boards, which are an indication of each component at each scanned plate so that it is possible, while the upper examination to determine exactly which electronic _9, a method and apparatus for testing electronic circuits Components of a plate are defective.

The errors can then be eliminated under favorable conditions, so that the plate is fine again

The device provides information based on the state the components of the circuit in an automatic manner by viewing and / or registering the information «, whereby the verification can be carried out without specialists »The device is suitable Preferably used for checking a wide variety of printed documents. Boards with circuits: © in and of the same series-produced type,

The method of the invention to the upper testing of printed circuits is characterized essentially in au§ ₉ that inaa _s used for each to überprüfend® type of printed boards, a plate homologous with identical © represents components as in test plates and this © component © properties and Have values that represent the target value © with a certain amount of accuracy than is required for the printed boards to be tested, and the masi di® mi ^ -z®ln®n component compares circuits with the entepreelacs ^ aoii components circuit.

In application represents one invention is ®ot @ @fat, electronic components of a gedru ^ ktesa Scfoaltimg sit ü®n homologous components of the "Bezugsiehaltwng
Results of this comparison di © O ^ © s »© issstias! N« n inauguration of the »®l« kt3Wii $ c}! En feiat
part of the circuit in relation to the »

According to the invention, one can match or disagree Specify the components digitally in the binary system as a function of predetermined tolerances »

According to one embodiment of a device according to the invention, electrical parameters are used in the same measuring device applied, which depend on several parts of the voice to be compared, the invention providing for the device in the course of the comparison, in particular with regard to the accuracy, to adapt to the pair of components "

According to a further feature of the invention, the various Pairs of components connected one after the other to the measuring device and compared in a bridge circuit.

The invention comprises a double comparison of the components to be tested with the homologous components of the reference circuit. In which the first comparison the current is sent through in one direction and in the second comparison in the opposite direction so that it is possible to find polarized electronic components the effect of which depends on the direction of the current, such as diodes or alloy transistors.

The first review takes place in a comparison in which the electronic components one after the other in a specific order be checked, and the second review happens during one second comparison in which the electronic components are checked in the reverse order »

According to a further feature of the invention, the comparisons controlled by a counting device which controls a selection device associated with an actuation circuit. Of the the first comparison is then carried out during the count and the second comparison during the countdown.

009823/1102

According to the invention, the double checking is also carried out for non-polarized ones Components, such as resistors and inductors, carried out to determine whether the data of the tested component have a value that is outside the tolerance range with respect to the nominal value of the homologous element of the reference circuit lies.

The invention is described below with reference to schematic drawings described in addition using several design examples,

Fig. 1 shows schematically the operation of the device according to the invention;

Fig. 2 is a highly schematic embodiment the device according to the invention;

Fig. 3 is a block diagram of an apparatus according to the invention;

Fig. 1 is a partial view of an apparatus according to the invention;

Fig. 5 shows the logic diagram of part of the device according to the invention in a first one Embodiment;

Fig. 6 shows the logic diagram of part of the device according to the invention in one second embodiment;

Figure 7 is a circuit diagram of part of the apparatus of the invention;

Fig. 8 is a perspective view of part of the device according to the invention;

9 and 10 show electrical circuit diagrams, and

Figure 11 is a perspective view of an apparatus according to the invention.

009823/1102

Fig. 1 shows a board 10 to be tested having a printed circuit board comprising a number of components, one of which Resistor 11 with its two connections 12 and 13 and a capacitor m with its two connections 15 and 16 are shown are.

According to the invention, a reference plate 17 is used, whose Circuit corresponds to the circuit of the panels to be tested and has components that are homologous to the components of the panels to be tested Plate are, but have a greater accuracy than is required for the components of the card to be tested. The components of the reference circuit (reference plate) are very sufficient strict conditions as is customary for such purposes. the Reference plate 17 has a resistor 18, which corresponds to resistor 11 and has connections IS and 20, and a capacitor 21 with connections 22 and 23, which the capacitor IH corresponds to the reference plate, etc, \

According to the invention, an electrical circuit is established between the resistors 11 and 18 by connecting the terminals 13 and 20 of the resistors 11 and 18 to a conductor I ₁ on the one hand and the. Connections 12 and 19 of these resistors to a line I ₂ , so that the resistor 11 can be compared with the resistor 18 by means of a _{measuring device M connected to the lines I 1} and I _{2 when both resistors are supplied with current, so that} whose agreement with a predetermined tolerance, which can be determined beforehand, can be determined.

Analog electrical circuits are then produced for the capacitor m and the capacitor 21 by connecting the connections 16 and 23 of these capacitors on the one hand and the connections 15 and 22 on the other hand and connecting the connecting lines to the measuring device M in the same way as described above.

0Ö9823 / 11Q2

The measuring device M comprises Toleranzeinstellvorrichtungen, as shown schematically in R, so that the capacitors 14 and 21 can be compared to the same tolerance as the resistors 11 and 18 or with a ¹ different tolerance.

The invention also provides for the automatic establishment of the desired connections between the electronic components and other circuit parts when a board to be tested is set up the plate and the rest of the system.

Fig. 2 is a highly schematic embodiment of the Vorsieh »W processing according to the invention. In this embodiment, the measuring device comprises a voltage generator 25 and a measuring apparatus 24. In order to compare an element, for example the resistance 11 of the plate to be tested with the homologous element 18 of the reference plate, an electrical circuit is produced by means of a selector 40 by the connections 13 and 20 of the resistors 11 and 18 connects to the connection of the generator 25 and on the other hand a connection 26 between the connections 12 and 19, to which the measuring apparatus 24 is connected by means of the selector 40.

The selector, preferably controlled by a counting device 41, which receives its counting commands from an actuation circuit 42, . establishes connections between the homologous elements one after the other the plate to be tested as well as the reference plate and the generator 25 or the measuring apparatus 24.

In a first corresponding to the upward counting of the device 41 The elements 11, 14 etc. of the test phase are sequentially comparing the test plate with the homologous elements 13, 21, etc., the current delivered by the generator 25 in a certain Direction flows through the homologous components. In a second the

009123/1102

Downcounting of the device M compares the corresponding test phase one after the other in the reverse order as in the first test phase the components of the board to be tested with those the reference plate, with the current in the homologous components in the opposite direction as during the first test phase flows "

According to a peculiarity of the invention, the non-polarized components of the components to be tested are left during the first comparison phase Plate emerge, which in terms of the value of the homologous components of the reference plate - within the predetermined tolerance limits a have a higher value, and during the second phase those components are allowed to emerge which, with respect to the homologous Components of the reference plate - also within the predetermined tolerance limits - have a lower value.

The double comparison also enables the verification of the polarized electronic components. According to the invention, this review is carried out during the first phase by that the value of the direct impedance of the polarized components (e.g. diodes or transistor junctions) with a first impedance value an existing circuit on the reference board is compared. During the second phase, the verification is carried out in such a way that that the value of the reverse impedance of the polarized components of the board under test with a second impedance value of the same circuit is compared.

3 to 11 relate to an embodiment of a device according to the invention. In this embodiment, an adapter 50 is in a slot 56 (Fig. 8), the front of which is from a pivotable flap 57 can be closed. In the drawer are horizontal slide rails 58, 59 for guiding a plate 60 attached to the center one of the shape of the panel to be tested 51 has adapted recess; the plate is made by inserting it

ÖÖÖ823 / 1102

fastened by pegs 62 located on the periphery of the opening of the plate 60 into the holes 61 made in the plate 51 on the plate 60. In the insert 56 there are also two movable plates 63 and 64. On the plate 63, buttons 52 are elastically arranged by means of springs 32 in accordance with the connections of the components of the plate to be tested. The plate Bk carries pins 33 elastically attached by means of springs 35 which absorb the force exerted by the buttons 52 and are thus intended to avoid deformation of the plate 51. The vertical approach of the plates 63 and 6U to the plate 51 is controlled by screw drives which are actuated by a motor 65, which in turn is set in motion by microswitches 66. One of these switches is operated as soon as the flap 57 is folded down in order to close the drawer 56. The others interrupt the loading circuit of the motor 65 as soon as the buttons 52 have sufficient electrical contact with the plate 51.

The buttons 52 connect the plate 51 to a selector 53, which is represented by a plurality of lines, which is shown schematically in FIG are connected to the various components of a reference plate 55 which, for their various circuits, is related to the plate 51 to be tested is identical, the components of which are homologous to those of the plate to be tested, but with a very high degree of accuracy are made.

'' About the connections of a component to be tested and the connections To connect the homologous component of the reference plate to a measuring device 69, the selector 53 consists of relays, for example from "Reed '^ relays, each relay having four sets of contacts, their contact springs 120, 121, 122, 123 (Fig. 7) with the corresponding fixed contacts 12 «*, 125, 126, 127 can work together. The relay combination is preferably according to relay matrices distributed in eight lines and eight columns (for a device with octal numbering), a plurality of such matrices stacked one on top of the other are. Such a structure enables an apparatus

009823/1102

with a certain number of relays, which can test an equal number of components, the capacity of the apparatus according to the Invention to increase in a simple manner by adding one or more additional relay matrices. In the example with matrices of eight lines and eight columns, five matrices are used to determine a selector with 320 lanes each, with the Tracks have four wires that form the input of the selector. The output of the selector 53 is made up of three connections 65, 66, 67 (Fig. 3), the first two connecting the selector to a voltage generator 68 and the third connecting the selector to the measuring apparatus 69, the output 70 of which is connected to a, ner actuation circuit 71 is connected »This is through a Connection 72 is connected to the voltage generator 68 and controls through a connection 73 a counting device 74-, which in turn controls the matrix selector 53 by means of a decoding device 75.

In one embodiment of the device according to the invention, in which the results are to be displayed, is the actuating device 71 connected by a connection 76 to a viewing device (FIG. 5), to which by a connection 78 the likewise information passed from the connection 79 to the actuating device 71 can be passed by the decoding device ..

In another embodiment in which the test results are printed should appear and the structure of which is shown schematically in Fig. 6, connect a line for the print commands S0 \ and a line 70 'the actuator 71 with a pressure device 81, at which a line 82 from the decoding device 75 also ends.

In both embodiments, the actuating device 71 directs the sequence of the various test sequences as a function of one from the measuring apparatus 69 output signal. This apparatus (Fig. 7)

009823 / i102

is connected by terminals 90 and 91 to the generator 68 and by terminals 92, 93, 9H to the matrix selector 53 and comprises a first amplifier 95 of gain + A ₁ , the input of which is through a conductor 96 to the point connected to the terminal 90 a is connected, and the output of which is assigned to a voltage comparator 105, at which an amplifier chain 97 also ends with amplifiers 98 and 99 which are connected in series and have corresponding amplification factors + A "and -Ag 93, the other connected to ground 100 ₀ - The gain of the amplifier 99 is adjustable, e.g. ₀ by a movable contact 101, which can interact with the fixed contacts 102, 103, 104, which form the ends of resistor circuits of different values «

The output of the comparator 105 forms the actuation factor of device 71 “At this output there is a voltage or digital Information "1" if the algebraic sum of the input voltages of the comparator is positive or equal to zero, and es there is no voltage corresponding to the digital information "0" if the algebraic sum of the voltages at the input of the Comparator8 is negative «

A double changeover switch with movable contacts 106 and 107, which are connected to the stops 90 or 91 and can interact with fixed contacts 108, loS or 110, 111, is used to reverse the direction of the current emitted by generator 68 in the homologous components, e.g. 112 and 113 of the board to be tested and the reference board, respectively. In the position of the movable contacts 106 and 107 shown in solid lines in FIG. 7, the current flows in the direction of the arrow p «j. In the position of the contacts shown in dashed lines, the current flows in the opposite direction indicated _{by the arrow p 2.}

008823/1102

- αϊ -

An interrupter 84 is provided to start the apparatus. Seeo In the embodiment for displaying the results, luminous disks 85 and 8B show defects on the board to be inspected or the end of the test sequence at “In the embodiment in which the test results appear printed, is only the light panel 86 intended to indicate the end of a test sequence "

The operation of the apparatus according to the invention is the following "After providing a Bezügsplatte, the movable contacts 106 and 107 of the measuring apparatus 69 in the embodiment shown in Fig. 7 by the solid line position _t and the movable contact 101, the gain (-A ₃ ) of the amplifier 99, interacts with one of the fixed contacts 102, 103, 1OH to define the permissible tolerance of the individual components of a board to be tested. Then such a plate is inserted into the slide-in unit 56 o Closing the flap 57 actuates the microswitch 66 of the motor 65 on the one hand. Approach of the planes 63 and 64 of the adapter 50 and on the other hand causes the interrupter 8H to close.

In the starting position of the counting device 74, the decoding device 75 actuates the relay K ₁ (FIG. 7) of the die selector 53, the contact springs 120, 121, 122 and 123 of this relay interacting with the corresponding fixed contacts 124 ₉ 125, 126 and 127 «The contacts 124 and 125 are connected to the buttons 52, which interact with the connections of a first component 112 of the board to be tested, and the contacts 126 and 127 are connected to the connections of the homologous component 113 of the reference board. Since the movable contact spring 120 is connected to the stop 92, the movable contact springs 121 and 122 are connected to the stop 93 and the movable contact spring 123 is connected to the stop 94 of the measuring apparatus 69, the components 112

009823/1102

- 12 -

A current flows through 113 and flows back to ground from the stop 90 connected to the generator 68 through the following circuit: movable contact 106, stop 92, movable contact spring 120, component 112, movable contact spring 121, movable contact spring 122, component 113 of the reference plate , Spring 123, stop 9t, movable contact 107 and stop 91 _s

If the value of component 112 of the * board to be tested is higher is than the value of the homologous component 113 of the reference plate, but within the tolerance range selected by means of a movable contact 101, the comparator 105 does not give any Tension off. i.e. at its output is the digital information null ο

If χ is the resistance 113 of the reference plate and χ + dx is the Is the resistance value of the component to be tested 112, the electrical voltages in points a and a * are related

^V a s2 + dx

to each other, as the corresponding electrical circuit diagram in Fig. 9 shows, in which the amplifier chain 9? is replaced by a single amplifier with the amplification factor -G ₂

t The voltage is at input B of the cosparator 105

v _B = r "A ₁ - ν. .G ₂

■ ΐ

If you consider the gain of the amplifiers 95, 98 and 99 so

chooses that the absolute ratio de? Gain factors G ₂ ⁱ J _x

'is equal to 2 + 2 ~, then the voltage Vg is ne as long as it is negative «Mi · the distance sum value of the component 112 is below the selected tolerance, i.e. - ~ ·

008121/1102

190029a

If, however, the value of the component 112 of the board to be tested is higher than the value of the homologous component 113 of the reference. plate, outside the selected tolerance range, then the voltage output by the amplifier 95 is higher than or equal to the voltage emitted by the "V er stronger chain 98, 99, and the Comparator 105 gives the voltage or digital information signal 1, which is passed through conductor 70 to the actuation circuit 71 arrives.

The voltage value at the connections of the resistor q has no influence on this and can be inaccurate without affecting the accuracy affect the measurement.

In the embodiment of the device according to the invention, in which the result is to be displayed, the voltage or digital information signal "1" at the input of the actuating device 71 triggers a display in the viewing device, which means that the component currently being tested is defective _O

When a printing apparatus 81 embodiment comprising the actuator 71 dissolves when it receives at its input a digital information "1", a pulse to the printing operation, whereby the display of the defective component on a continuously rotating strip chart recorder, the printing apparatus appears _o dissolves by the Connection 83 emits a signal which interrupts the advance of the counting device for the duration of the print.

In the first embodiment, a defective component can Interrupt the test sequence by pressing a suitable interrupter WO can be started from the beginning (Figo 5). In the second embodiment, the test sequence runs continuously further, since a component with a tolerance error is indicated on the strip chart recorder by a running Hummer, which is too serves to identify them. ; -

008823/1102

In both embodiments, the payment device controls after the selection of the relay K ^ by means of the decoding device, the selection of the following relay of the selector 53, that is, the relay K corresponding to the test of a second component of the board to be tested, then the relay K _3. "O etc.

The invention provides, during the count, the components formed by resistors or inductances of the board to be tested and the direct impedances of the semiconductor (diode or transistor junctions) to compare "To this end, the invention provides a homologous member of a diode of the tested plate, z" B _o the diode 130, a circuit 131 before which is mounted on the reference plate and resistors 132, 133 and a diode includes 0

The invention provides for checking the transitions of a transistor 135 of the board to be tested to compare each of the transitions one after the other with a circuit mounted on the reference plate ₉ such as the circuit 13S for testing the emitter-base transition of the transistor 135 and as the circuit for the collector-base junction of the same transistor "

The moving contacts are at the end of the counting process 106 and 107 of the measuring device 69 in the position shown in phantom in Fig. 7, whereby the direction of the generator 68 supplied current flow is reversed.

The downward counting of the counter 74 controls the decoding system 75 to select the relays of the die selector 53, this selection one after the other and in the opposite direction as in the counting up happens »

During the first phase described above, the up-counting of the counting device corresponding to the components of the to be tested Disk are discovered that have a tolerance error, discovered »on in the second, corresponding to the reverse payment

009823/1102

Phase the components of the panel under test that have a system failure. With a component 112 of the plate to be tested with a value which is lower than the value of the homologous component 113 of the reference plate, so that the system error is internal is half of the selected tolerance range, the comparator gives 105 does not emit any voltage, i.e. it supplies the digital information

00 If, on the other hand, the system error of component 112 of the panel to be tested is outside the selected tolerance range, there is the comparator 105 sine voltage with the digital information

Fig. 10 shows the corresponding electrical scheme. If χ the Value of the reference component and χ + dx the value of the building to be tested part is the ratio of the electrical voltages in the Points a and a * the following:

V ^ χ- dx

and one can say ax of great approximation ^:? a _ «. dx

V ^x

Since the amplification factor of the amplifiers 95, 98 and .99 is chosen so that the absolute value of the ratio ζ2 is equal to 2 ♦ ~ C as described above) _t is the ³ ^ T voltage in point. B negative if the system error on component 112 of the xu-testing plate is within the selected tolerance, whereas the voltage is positive or zero if the system error is outside the selected tolerance range.

As in the counting phase, the digital information output by the comparator 105 is passed to the actuating device 71 which, in the case of the viewing device embodiment, controls the display of a system on the device 77 and, in the case of the embodiment with a printing device, the printing of a system error on the strip chart recorder Device Sl ₀

009823/1102

During the second test phase, i.e. "during the backward" Counting the counting device 7if are the reverse impedances the semiconductor and transistor junctions are checked by comparing their value with the homologous value present on the reference plate will.

The result of the setting of the gain factor of the amplifier 99 by means of the movable contact 101 resulting tolerance can be tested either at the beginning for all components Plate or changed in the course of a test cycle.

With an apparatus according to the invention having a clock with a frequency of 100 Hz, good results have been obtained; A component can be tested in 10 ns, ie in the case of a selector with 320 lanes, a test process takes 6 seconds (320 χ 2 χ 10 ms).

008823/1102

Claims (1)

Claims Io test methods for electrical or electronic components having circuits, for example printed circuits, characterized in that one of the type of plate to be tested analog reference plate is produced, the electrical or electronic components of which are those for the components of the panels to be tested have the required characteristics, but with greater accuracy, and that each electrical or electronic component of the plates to be tested is compared with the corresponding component of the reference plate. 2. The method according to claim 1, characterized in that that the test includes a first phase during which the comparisons are made with an electric current, which reads in a certain direction through the components of the plate to be tested and those of the reference plate, as well as a second phase during which the same components are compared with a current flowing in the opposite direction « 3 ο Method according to claim 1 and 2, characterized in that g e k e η η that in the second test phase the comparison takes place in the reverse order as in the first test phase. > t, method according to claims 1 to 3, characterized in that, in the first test phase, for the non-polarized electrical components, those showing defective or excessively tolerated values with regard to the characteristic value are eliminated, and those in the second test phase We separate out components that have excessively tolerated or defective values. 008823/1102 5 ο method according to claim 1, characterized in that the comparison of the passive and active components in takes place in a certain order. 6 »Method according to claims 1 to 5, characterized in that g e k e η η draws that the comparison in the active components, such as diodes, transistor junctions, etc. with predetermined ones circuits attached to the reference plate are carried out « 7. The method according to claim I _9, characterized in that the permissible tolerance of the comparison values is adjustable = bar 8. Device for applying the method according to one of the preceding Claims, characterized by means to successively each electrical or electronic construction to compare part of a plate to be tested with that of a reference plate (55) to determine the characteristics of the homologous components of the reference plate outside or within the tolerance range of the components. 9. Apparatus according to claim 8, characterized by means for defining the adjustable tolerance limits for the comparisons ₀ 10. The device according to claim 8, characterized by a counting device (7H) for determining the comparison « follow by counting up or down as well as by a Actuating device (71) for controlling the comparison sequence " 11ο device according to claim 8 and 10, characterized that the counting device (7MO through a decoding device (75) is connected to a matrix selector (53) is to successively a component of the board to be tested with the homologous component of the reference plate (55) to be selected # 008823/1102 12 α device according to claim 8, 10 and H ₉ characterized by a heating device (69), the input of which is connected to the die electox ¹ (53) and the output of which is connected to the actuating device (71>, and which is used for each component to be tested Plate determines the agreement or non-agreement - within the preselected tolerance range - with the homologous component of the reference plate (SS). 13. The apparatus according to claim 12, characterized in that the measuring device has a comparator whose Inputs consist of two amplifier chains, one of the chains having an adjustable gain factor. IH. Device according to Claim 8, characterized in that it has devices (81) for printing the test results. 15. The device according to claim 8, characterized in that it has devices (77 ·> .aufweis the test results to aachen visibly. 16. The device according to claim 8, characterized in that it uafasst means that the ^ automatic start of a Ensure the test cycle by attaching a plate to be tested. 17. The device according to claim 8 to 16, characterized in that the devices that the automatic Ensure the start of a test cycle, one through a flap have lockable insert »whose closure microswitch pressed, the approach movement of the plate to be tested by means of a tactile and «into the supporting device of the panel to be tested control, the tactile device from elastic on one in the Inset plate attached to organs, according to one of the connections of the various components of the to be tested Plate corresponding device are arranged, and wherein the support device is made of elastic on a second in the insert and pegs fastened under the plate to be tested stands (Fig * «O. 009823/1102 Blank page