JPS6133442B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-dimensional automatic contour measuring method and apparatus, particularly a two-dimensional automatic contour measuring method and apparatus capable of automatically converting the external shape of a workpiece enlarged by a projector into data. It is related to the device.

Projectors are used to magnify objects to be measured, such as small precision parts or IC patterns, to observe, measure, or take photographs, and are extremely effective for precision measurements. In order to convert the external shape of the object to be measured enlarged on the projection plane into data such as coordinate values, in the conventional method, the feeding information of the stage is read manually and this information is stored in computer memory, etc. This method requires extremely complicated work, and there is a problem in that it is extremely difficult to convert the external shape into data, particularly for objects to be measured that have complicated external shapes.

The present invention was made in view of the above-mentioned conventional problems, and its purpose is to relatively feed and drive the workpiece table while automatically following the external shape of the object to be measured without requiring manual operation. However, it is an object of the present invention to provide a two-dimensional automatic contour measuring method and apparatus that can accurately convert the contour shape of a workpiece into data at each feeding step.

In order to achieve the above object, the method according to the present invention includes the steps of: aligning an object to be measured such that the contrast ratio becomes a predetermined ratio within the loop of a loop-shaped image sensor having a plurality of photoelectric conversion elements arranged in a closed loop; projecting the object to be measured across the loop, detecting the crossing positions of both ends of the object to be measured across the loop, calculating a moving direction that maintains the brightness ratio in the loop at a predetermined ratio based on the crossing positions of both ends, and calculating the moving direction along the moving direction. Repeating feeding to move the object to be measured by a predetermined amount, and during the feeding, each raw point representing the intersection position of the loop and the object to be measured is determined based on the detected position information of at least one side crossing the loop and the feeding information. It is characterized by calculating and converting the outline of the object to be measured into data.

Furthermore, the apparatus according to the present invention includes: a projector having a stage on which an object to be measured is placed and movable in any direction; and a plurality of photoelectric conversion elements provided on the projection surface of the projector and arranged in a closed loop. a loop-shaped image sensor having a loop-shaped image sensor; a position detection circuit that detects the intersection position of both ends of the loop where the object to be measured crosses the loop; a feed control device having a drive means for feeding the stage so that the contrast ratio within the loop becomes a predetermined ratio; and a feed detector that detects and outputs the feed amount; and one of the position detection circuits. a measuring circuit that measures each raw point representing the intersection position of the loop-shaped image sensor and the object to be measured based on the detected position information of the sensor and the output of the feed detector, and converts the outline of the object to be measured into data. include.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of a measuring device to which the present invention is applied. and Y servo motors 18 are provided, and both motors 16 and 18 move the stage 14 to the
The object is moved by an arbitrary amount in the direction. The feed information of the stage 14 by both servo motors 16 and 18 is detected by a feed detector consisting of an X pulse generator 20 and a Y pulse generator 22 provided in each servo motor 16 and 18.

The projector 10 is equipped with a well-known optical device, and the outline of the object 12 to be measured is optically enlarged and displayed on a projection surface. The projection plane in this embodiment has a first projection plane 24 for normal visual observation and a second projection plane 26 for automatic contour measurement. The contour shape is projected onto both projection surfaces 24 and 26 through the projection.

A loop-shaped image sensor 3 is provided on the second projection surface 26.
As shown in FIG. 2, this loop-shaped image sensor 30 has a plurality of photoelectric conversion elements 32 arranged along a closed loop, a circular loop 100 in the embodiment, Each photoelectric conversion element 32 is arranged close to each other on the loop 100, and can output an electrical signal when light is incident on each photoelectric conversion element 32.

The output of the image sensor 30 is supplied to a position detection circuit 34, and when the projected image of the object to be measured 12 crosses the loop, the position of the photoelectric conversion element 32 traversed can be electrically detected.
Then, the position information detected at both ends of the position detection circuit 34 is supplied to the feed control device 36.
6 supplies a feed control signal to the servo motors 16 and 18 in order to control the feed of the stage 14 along the calculated moving direction.

The position detection information of one of the position detection circuits 34 is supplied to the measurement circuit 38, and the information sent from both pulse generators 20 and 22 mentioned above is similarly supplied to the measurement circuit 38, and from this information, the measurement circuit 38 can measure each raw point of the object to be measured 12 and convert the contour of the object to be measured 12 into data.

A preferred embodiment of the present invention has the above configuration,
The operation of the present invention will be explained below.

In the present invention, such contour measurement is started by fixing the object to be measured 12 on the stage 14 and creating its projected image on both projection planes 24 and 26 in the same way as in normal projection work. A characteristic feature is that a part of the object 12 to be measured is always projected within the loop 100 of the image sensor 30 at the start of measurement, that is, the initial position is set so that the projection plane crosses the loop 100. It is. By setting such an initial position, the image sensor 30 can always grasp and follow the projection plane of the object 12 within the loop 100 during contour measurement.

In the present invention, the contrast ratio of the projected image within the loop 100 at the initial position can be set to any desired ratio, but in the embodiment, it is preferable to set this contrast ratio to approximately 1:1; It is possible to reliably prevent the projected image from deviating from the image sensor 30 during tracking.

Once the initial measurement position is determined as described above, the positions of both ends of the object to be measured 12 crossing the loop 100 are then detected. That is, as shown in FIG. 3, at the initial position, the projected image of the loop 100 is approximately divided into halves, and at this time, the positions A ₁ and A ₂ of both ends are detected by the position detection circuit 34. Ru. That is, the photoelectric conversion element 32 on the loop 100 has no electrical output from the dark area with both ends A ₁ and A ₂ as boundaries, and a predetermined electrical output from the bright area, and these electrical outputs are By processing, it becomes possible to detect the positional information of both ends from the photoelectric conversion element 32 located at the bright/dark boundary.

Next, the feed control device 36 calculates a moving direction in which the contrast ratio in the loop 100 is maintained at a predetermined ratio based on the end positions A ₁ and A ₂ , and the object to be measured 12 is moved along the moving direction. That is, feed control is performed to move the stage 14 by a predetermined amount. The feed control device 36 is supplied with both end position information A ₁ and A ₂ from the position detection circuit 34, and the moving direction is calculated from both signals. In the initial state shown in FIG. Since the projected images within are positioned with a contrast ratio of 1:1, a movement amount a is set as the initial movement direction on the extension line of both end positions A ₁ and A ₂ . The amount of movement at this time is set to a predetermined amount smaller than the radius of the loop 100, and the feed control device 36 supplies such a feed control signal to both servo motors 16 and 18 to relatively feed and move the stage 14. can do. The moving direction is set as a moving direction that maintains the contrast ratio within the loop 100 at a predetermined ratio, for example, 1:1 in the embodiment, and since the contrast ratio is 1:1 at the initial position in FIG. is also set as an extension of both end positions. Furthermore, by setting the amount of movement smaller than the radius of the loop 100, the projected image is prevented from deviating from the loop 100.

FIG. 4 shows the feeding state from the second time onwards, and when the projected image outline of the object to be measured 12 is not a straight line after the feeding by the above-mentioned feeding control device 36, the contrast ratio in the loop 100 is 1:1. In FIG. 4, it can be seen that the dark areas indicated by diagonal lines are increasing. Therefore, from the state shown in FIG. 4, in order to keep the brightness ratio constant, both end positions A ₁ and A ₂
In addition to a, which is the extension line of The feed control 36 calculates the movement direction by the calculation described above, and then supplies signals along this movement direction to both servo motors 16 and 18 to move the workpiece table 14. In other words, the object to be measured 12 can be moved by a predetermined amount. In contrast, FIG. 5 shows a state where the dark areas are smaller than the bright areas, and at this time, the amount of movement c in the direction of making the contrast ratio 1:1 is calculated in the same way.

As described above, according to the present invention, the relative movement of the stage can be performed by automatically following the projected image captured by the image sensor 30, and as a result, no manual operation is required. It becomes possible to trace the image sensor 30 along the outline of the object to be measured 12 from any predetermined initial position without having to do so. This state is shown in FIG. 6, and it is clear that the loop 100 of the image sensor 30 is moving relative to the contour of the projected image with certainty.

As described above, the automatic feeding of the present invention becomes clear. In such automatic feeding, the center O of the image sensor 30 has an error relative to the contour shape of the object 12 by the radius R of the loop 100. As a result, the contour shape cannot be accurately determined simply from the feed information of the feed detector consisting of the pulse generators 20 and 22, and the maximum R
Because of this error, it is impossible to perform accurate measurements. The present invention is characterized in that each raw point of the object to be measured 12 is measured based on the intersection position of the loop 100 that intersects the object to be measured 12 during feeding.

That is, in the present invention, in addition to the feed information representing the center position O of the loop 100, the detection position information of at least one side across the loop 100, A2 in the embodiment, is used to measure each raw point of the object to be measured 12. In this embodiment, the sending information X, Y from each pulse generator 20, 22 is calculated with one of the position information A2 from the position detection circuit 34 in the measurement circuit 38.

For example, as shown in FIG.
consists of radius R and angle θ, and the feed information X,
Correction amounts ΔX and ΔY for Y can be given. Then, the measurement circuit 38 calculates the contour of the object 12 (X+△X, Y+△
Y) can be accurately converted into data.

As described above, according to the present invention, it is possible to automatically follow a projected image and accurately convert its outline into data.

FIG. 7 shows another embodiment used in the present invention, and while the embodiment in FIG. 2 has a plurality of photoelectric conversion elements 32 arranged directly in a circular manner on the loop 100, in FIG. The photoelectric conversion element 32 is characterized by using a normal linear linear array and having a plurality of optical fibers 40 provided between the linear array and the loop 100, with one end of the optical fiber 40 facing the loop 100 on the projection plane. The photoelectric conversion elements 32 are arranged so that the other end faces the linear array including the photoelectric conversion elements 32. Therefore, according to this embodiment, by utilizing the flexibility of the optical fiber 40,
The loop shape can be arbitrarily selected and its size can be freely changed, and a loop-shaped image sensor suitable for various measurements can be constructed using a single linear array.

As explained above, according to the present invention, even if the object to be measured has a complex shape, the contour shape can be automatically converted into data with high precision, and an extremely effective measurement method can be used for measuring the external dimensions and other purposes. It has the advantages that it can offer.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing a preferred embodiment of a two-dimensional automatic contouring device to which the measurement method according to the present invention is applied, and Fig. 2 is an explanation showing a preferred embodiment of the loop-shaped image sensor in Fig. 1. Figures, 3rd, 4th,
Figures 5 and 6 are explanatory diagrams showing the action of the present invention, respectively.
FIG. 7 is a schematic configuration diagram showing another embodiment of a loop-shaped image sensor suitable for the present invention. DESCRIPTION OF SYMBOLS 10... Projector, 12... Measured object, 14... Stage, 16... X servo motor, 18... Y servo motor, 20... X pulse generator, 22... Y pulse generator, 26... Second projection surface, 30... Loop-shaped image sensor, 32... Photoelectric conversion element, 34
...position detection circuit, 36...feeding control device, 38...measuring circuit, 40...optical fiber.

Claims (1)

[Claims] 1. Project a part of the object to be measured into the loop of a loop-shaped image sensor having a plurality of photoelectric conversion elements arranged in a closed loop so that the contrast ratio becomes a predetermined ratio, and cross the loop. Detecting the intersection positions of both ends of the object to be measured, calculating a moving direction that maintains the contrast ratio in the loop at a predetermined ratio based on the crossing positions of both ends, and moving the object to be measured by a predetermined amount along the moving direction. The feeding is repeated, and during the feeding, each raw point representing the intersection position of the loop and the object to be measured is calculated based on the detected position information of at least one side crossing the loop and the feeding information, and the outline of the object to be measured is calculated. A two-dimensional automatic contour measurement method characterized by converting it into data. 2. A projector having a stage on which an object to be measured is placed and movable in any direction; a loop-shaped image sensor provided on the projection surface of the projector and having a plurality of photoelectric conversion elements arranged in a closed loop; A position detection circuit that detects the intersection position of both ends of the loop where the object to be measured crosses the loop using the electrical output of each photoelectric conversion element, and a position detection circuit that processes the output of the position detection circuit to determine the brightness ratio of the projection surface of the object to be measured within the loop. a feed control device having a drive means for feeding the stage to a predetermined ratio; a feed detector for detecting and outputting the feed amount; detected position information of one of the position detection circuits; A two-dimensional automatic contour measuring device comprising: a measurement circuit that measures each raw point representing the intersection position of the loop image sensor and the object to be measured based on the output of the feed detector and converts the contour of the object to be measured into data; . 3. In the device according to claim 2, the loop-shaped image sensor includes a plurality of optical fibers each having one end facing the projection surface and the other end facing the photoelectric conversion element, and one end of each optical fiber facing the projection surface. A two-dimensional automatic contour measuring device characterized by being arranged in a loop shape.