SU670943A1 - Graphic information readout device - Google Patents

Description

one

The invention relates to automation and computer technology, in particular to devices for reading graphic information, and can be used to measure the coordinates of the centers of flat convex shapes of a regular shape, such as the centers of holes on printed boards and negatives of printed circuit boards.

A device for reading graphic information is known, comprising a plate made in the form of two platforms X and Y, moved by jog motors along the guides in mutually perpendicular directions, a fixed projection screen mounted above the platforms, position sensors connected to the signal converters of the sensors in cis |) rotary code 1.

In this device, the pointing to the point whose coordinates should be read is performed by the operator in an enlarged image of the neighborhood of the encoded point. The exit to the vicinity of a point is accomplished by moving the platforms.

The disadvantages of such a device are the possibility of gross subjective errors introduced by the operator when pointing to a point, and depending on the duration of the measurement on the fitness and speed of the operator's reaction.

Devices are known for automatically reading the coordinates of planar images by scanning an image with a light beam and registering a change in reflected or transmitted light at points of change in the image contrast 2.

This device also contains two platforms moving relative to the sweep light beam, a light beam and a reference block with two sensors, displacement transducers and reversible counters.

The disadvantages of the device include the need to double-scan but mutually orthogonal axes in order to eliminate the uncertainty that arises when the scan is matched with the direction of the image line, and the need to process the received information on the computer to interpret it.

The closest to the technical nature of the proposed device is a device 3 containing nlans,

mechanically connected with schopper motors, position sensors connected to the inputs of the displacement quadrant formation unit, conversion channels, each of which contains a reversible counter, the inversion inputs and counting

the input of which is connected to the control and pulse outputs of the displacement quadrant formation unit, the drive control unit, the output of which is connected to the corresponding scap motor, and the information exchange unit (punched tape output unit).

The recognition of the coded elements of the drawing and the installation at the desired point are carried out by the operator using an optical screen, and the coding is carried out with automatic rounding of the magnitude of the coordinate increments to a value multiple of the fine paper grid; The drawing is applied. If the drawing element does not lie in the grid node, the operator manually types the value of the coordinate correction on the keyboard.

The disadvantages of this device are the dependence of the measurement rate on the operator and the possibility of gross subjective errors introduced by the operator, especially when reading saturated drawings.

The purpose of the invention is to increase measurement accuracy.

This goal is achieved in that the device comprises a plate positioning unit made in the form of an optically coupled light source and a photodetector located on both sides of the plate, the midpoint segment determining units, additional reversible counters, adders and logic unit. The input of the logic unit is connected to the output of the photoderipe, and the outputs are connected to one of the inputs of the information exchange unit and the mid-segment determination units, the other inputs of which are connected to the pulse output of the corresponding movement quadrant formation unit, and the outputs to counting inputs of additional reversible counters, the installation inputs of which connected to the bit outputs of the reversible counters of the conversion channels and through the adders to the inputs of the drive control units. The bit outputs of the additional meters are connected to the inputs of the adders connected, respectively, to the information exchange unit.

FIG. 1 shows a block diagram of the device. FIG. 2 explains the process of finding the center of a circular element on a photo pattern.

The measurement table 1 has a plate 2 on which the object to be measured is installed. The plate 2 is equipped with code screws X and Y connected to the jaw motors 3. The plate 2 of the measuring table 1 is connected to the position sensors 4 located along each axis of movement. On the base of the measuring table 1, a light source 5 and a photodetector 6 are installed, made on the basis of a photosensitive element, such as a photomultiplier, and connected to logic unit 7; The excitation windings of the scapular motors 3 are connected with the drive control unit 8. The outputs of the position sensors 4 are connected to the inputs of the displacement quadrant formation unit 9. The output of block 9 of the formation of the quadrant of movement of the connector with the counting input of the reversible counter 10 and through the block II of determining the midpoint of the segment with the counting input of the additional reversing counter 12.

The counting direction control outputs (+) and (-) of the movement quadrant formation block 9 are connected to the corresponding control inputs (+) (-) of the counting of the reversible counter 10 and the additional reversible counter 12, the outputs "O and" 1 of the reversible counter 10 - with one side with the inputs of the adder 13, and on the other hand with the inputs of the installation “O and” 1 additional reversible counter 12. Outputs “1 additional reversible counter 12 are connected to the second inputs of the adder 13 and to the information exchange unit 14.

The third group of inputs of the adder 13 is connected to the register of the X coordinate located in the information exchange unit 14, the outputs of the adder 13 are connected to the corresponding inputs of the drive control unit 8.

The control inputs of the block And the definition of the midpoint of the segment are connected to the logic block 7, under the control of which information is transmitted between different parts of the device. In order not to overload the circuit, some of the links in the drawing are not shown.

The device works as follows.

The measured object (drawing, photomask of the printed circuit board, chip mask, printed circuit boards, etc.) is mounted on the plate 2. Before the start of the coordinate reading process, the axes of the measured object and tablet 2 are aligned, and the origin is fixed. Thereafter, the reversible counters 10 and 12 are reset.

The listed measurement objects have one common property. They are a combination of areas of transparent and opaque areas. For example, opaque lines or figures (photo masks) are applied on a transparent base and, on the contrary, there are transparent lines or figures on an opaque base (holes in printed circuit boards, chip masks, etc.).

The light source 5 forms a parallel beam of light with a small cross-sectional diameter. The light beam falls perpendicular to the surface of the object being measured. Behind the plane of the object being measured, a photodetector 6 is placed directly against the source of light 5, which reacts to a change in the brightness of the light beam. When tablet 2 is moved in one direction or another, the light beam (the source of light 5 is stationary) draws a certain trajectory on the surface of the object being measured. At the same time it crosses the transparent and opaque parts of the object. Since the cross-sectional diameter of the light beam is chosen to be less than the minimum thickness, the illumination of the photodetector 6 changes as the tablet moves, and hence the output signal level of the latter from a certain maximum (in absolute value) value in the transparent area to a certain minimum value in the opaque area. Since the position of tablet 2 is known at any time, it can also be fixed at the moment when the receiver's illumination level changes, i.e., the coordinates of the point of intersection of the path of the light beam with any line or contour of the figure can be fixed. The proposed device can operate in several modes: reading the coordinates of the holes of printed circuit boards on a sample or photo mask, measuring masks or photo masks of chips in a given program, measuring flat geometric objects by scanning, etc. The most distinctive features of the proposed device are shown when the mode is implemented measurements of the coordinates of the holes of printed circuit boards for a given program. In the initial state, the tablet 2 of the measuring table 1 of the device is set at the origin, the reversible counters 10 and 12 and the coordinate registers in the information exchange unit 14 are reset to the initial state "O, the counting and reset inputs of the block 12 are open, the inputs of the photodetector 6 of the logical unit 7 blocked. From the information exchange unit 14, the coordinates JQI and 01 of the center of the next read leg are entered, which are specified on the drawing structure (input of the initial information can be made either from an intermediate medium: punched tape, magnetic tape, or directly from a computer using a communication channel). The codes of the specified coordinates of the center of the hole being measured are stored during the entire processing time of the hole. From the information exchange unit 14, the codes of coordinates of the hole being measured are fed to the inputs of the corresponding adders 13 and are one of the terms. The role of the second addendum is performed by the code for the current position of the tablet, taken from the transverse counters 10 coordinates X and Y. In this way, the information outputs of the adders 13 appear in the codes of the algebraic sum of the given and the current position of the tablet 2. At the same time, the adder 13 determines the sign of the result algebraic addition. The result of the addition and the sign of the sum arrive at block 8 of the drive control of the transfer plate 2. When the result of the addition is nonzero, the drive control block 8 turns on the stepper motors 3. The move control is determined by the sum sign and is chosen so that the object point with the given coordinates is consistent with the intersection of the light of the surface of the object being measured. In a more general case, the magnitude of the mismatch between the current and the specified position of the tablet can serve to set the speed of movement. Since the plate 2 is connected to the sensors of the 4 position, the impulsive (unitary) movement code, which with the corresponding sign generated in the form of output potentials (-f) (-), is generated last by the block 9 of the formation of the quadrant of movement in the process of the movement of the plate 2. by the same block 9, it is registered in the X and Y reversible counters: mainly 10 and additional 12. Since logical block 7 allows direct transmission from block 10 to block 12, the reversing counter 0 state is connected to the additional reversing counter 12, those thus eliminating the misalignment of the two parallel operating counters. As the plate 2 moves, the code stored in the meters 10 and 12 approaches the code of the given coordinate, therefore, the algebraic sum at the output of the adder 13 tends to zero. As soon as cvMMa becomes zero, the drive control unit 8 turns off the stepper motors 3. As a result, the light beam is inside the hole being measured, for example, as shown in FIG. 2. It is obvious that the position of the beam with respect to the true center of the hole is arbitrary, noting that the factors determining the true positive center of the hole are random in nature. After the light beam reaches the set point of the object to be measured, the movement of the tangent 2 is transferred to a special program of the logic unit 7. The first command of the logic unit 7 blocks the communication of the drive control unit 8 with the adders 13 and unlocks the input of the phototechnique 6. the x coordinate includes a jog motor X (3)

so that the platform moves in the direction of point a (Fig. 2). As soon as the light beam crosses the orifice boundary at point a, the signal level at the output of the photodetector 6 changes, which is fixed by logic block 7. Block 7 issues another command, according to which drive control unit 8 but X coordinates the engine X (3). At the same time, the command of the logic block 7 stops transmitting pulses from the output of block 9 to the counting input of counter 12, block II switches to division mode 2, and the direct connection between blocks 10 and 12 is blocked. With the subsequent command, the drive control unit 8 of the coordinate X again turns on the engine X (3), changing the sign of the opposite movement of the engine so that plan 2 moves in the direction of point a. At the same time, the current position of the tablet 2 continues to be recorded in the counter 10, i.e. when the light beam crosses the opening at point b and the unit 8 is driven by the X coordinate according to the next command of the logical block 7, the engine X stops, in the counter 10 the coordinate of the point is stored at. At the same time, in the additional counter 12, only / 2 of the traveled distance will be recorded, since the movement code arrives in the daip case at the input of the additional counter 12 e by the division factor 2, therefore, when the point is reached, the coordinate of the point is stored in the counter 12 coordinates definable expression

at | al y

 - -.

where Xa is the X coordinate of point a;

iai - limited length

points a and b.

Thus, in the counter 12 coordinates, the code of the XQ coordinate of the true center of the hole 0 is obtained.

Then logic block 7 unlocks the communication of block 8 of motor drive 3 with adder 13 and allows access to the input of the summation circuit of adder 13 of the additional counter status code X (12) and blocks the inputs connecting the adder 13 with register i; coordinates / YI block 14 exchange of information. In this case, at its outputs, circuit B1, the difference between the coordinate value of the true center of the hole XQ and the code of the current position of the plate Xb is generated. The device processes the specified difference and moves to the point with the coordinate o, and then proceeds to measure the coordinate YO of the true center of the hole, which is carried out similarly to that described for the coordinate X.

After reading the coordinates of the center of the hole at the command of the logic unit 7

the state of the additional counters 12 is read into the information exchange unit 14, by means of which the coordinates of the true center of the hole are either recorded on an intermediate carrier or transmitted directly to a computer. The final command of the cycle logic block 7 and reset the blocks of the device to its original state, after which it is ready to process the next hole.

Application of the proposed device provides automation of a number of technological works, in particular, certification of photomasks, printed circuit boards and masks of hybrid microcircuits, preparation of punched tapes for a drilling machine with programmed control, allows to increase the accuracy of measurements and completely eliminate gross errors of the turner.

Claims (3)

Invention Formula A device for reading graphic information, containing a tablet, mechanically connected with stepper motors, position sensors connected to the inputs of the displacement quadrant formation unit, transformation channels, each of which contains a reverse the counter, the control inputs and the counting input of which are connected to the control and pulse outputs of the displacement quadrant formation unit, the control unit of the drive, the output of which is connected to a corresponding stepper motor, and an exchange unit, information, characterized in that, in order to increase accuracy, it contains a unit for determining the position of the tablet, made in the form optically coupled light source and photodetector, located on both sides of the plate, blocks determining the middle of the segment, additional reversible counters, adders and logical the unit whose input is connected to the photodetector output, and the outputs to one of the inputs of the information exchange unit and the block to determine the midpoint of the segment, the other inputs1 of which are connected to the pulse the output corresponds to the quadrant quadrant formation unit, and the output D1, 1 - with the counting inputs of additional reversible counters, the installation inputs of which are connected to the bit the outputs of the reversible counters of conversion channels and through adders to the inputs of the drive control units, the bit outputs of the additional counters are connected to the inputs of adders connected respectively to the information exchange unit. F. Information sources taken into account during the examination I. Ashlev FR, Murphy E. V., Savard N. J. And computer-controlled coordinate-measuring mashine. “The Bell System Technical Journal, 49, No. 9, 1970, p. 2193. 2, Fedotov O. P. Processing of images from bubble cameras on raster decomposition devices. - In Sat. Materials II symposium on nuclear electronics. Dubna, 1964, JINR, p. 85. 3. USSR author's certificate No. 319844, cl. G 01 C 11/26, 1970.