JPS587639A - Two-axis position detection device - Google Patents

Abstract

PURPOSE:To improve the accuracy of detection by determining the central position of detected light images from the state of the binary signal train obtd. by magnifying the light images, detecting the one-dimensional space position thereof and discriminating the level of the detection signals. CONSTITUTION:A light image 11 is projected through a magnifying optical system 12 and is projected to a two-dimensional photoelectric detector 15. The image 11 is of a curciform shape, and the detector 15 has photoelectric arrays 25 disposed at 45 deg. angle with respect to the X-, Y-axes of the image 11 on the surface to the projected thereof. The outputs from the detector 15, that is, the outputs of the respective photoelectric elements of the arrays 25 are inputted to a level discriminator 16 in accordance with the input from a sweep pulse generator 18. The discriminator 16 discriminates the levels of the respective inputs and forms a binary signal train. The outputs of the discriminator 16 are inputted to a signal processor 17, and the signals are processed with the processor 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical position detection device, and more particularly to a two-axis position detection device suitable for automatically positioning a mask plate or the like.

As a conventional position detection device, an analog photoelectron microscope as shown in FIG. 1 is known.

In other words, the optical image 1'Jf is a separate image projected onto the optical detector 4 via the projection lens 2 and the vibration slit 3,
As shown in Fig. 2 (aJ), the output waveform from the photoelectric detector 5 (Fig. 2 ( b)).

Although biaxial detection is possible with this method, the automatic detection range is narrow and the linearity with respect to the detected position is low, and it is only a means of determining whether or not it is at the center. In addition, the adjustment was delicate, and because it had moving parts, it lacked reliability over its lifetime.

An object of the invention is to provide a two-axis position detection device with good detection accuracy and linearity.

In order to achieve such an object, the present invention includes a first means for enlarging an optical image and a one-dimensional spatial position of the enlarged optical image in a device for optically detecting the position It of an optical image. a second means for determining the level of the detected electric signal; and a fourth means for determining the center position of the detected optical image from the state of the binary signal string obtained by the means. The optical image has two linear parts parallel to the X-axis and the Y-axis, and the second means is a photoelectric array arranged at an angle of one foot with respect to the optical image. .

The invention will be described in detail below using examples.

FIG. 3 is an explanatory diagram showing an embodiment of a two-axis position detection device according to the invention. There is an optical image 11 which passes through the entire magnifying optical system 12 and is projected onto a two-dimensional photoelectric detector 15 . The optical image 11 has a cross shape as shown in FIG. 4(a), and the two-dimensional photoelectric detector 15 is arranged on its projection surface at an angle of 45 degrees with respect to the XY axes of the optical image. It has a photoelectric array 25.

The two-dimensional ″/l, the output from the electric detector 15, i.e.,
The output of each photoelectric element of the photoelectric array 25 is input to the level discriminator 16 based on the input from the sweep pulse generator 18, and this level discriminator 516 discriminates the level of each human power and makes it a 2@signal train. Level 1] The output of the separator 16 is input to the signal processor 17, where the signal is processed.

The specific circuit configuration of the two-dimensional photoelectric detector 15, the level determination 416 of the sweep pulse generator 18, and the signal processor 17 is shown in FIG.

Each of the outputs of the level discriminator 16 is connected to each negative input terminal of AND gates 65 and 66, and the output of the sweep pulse generator 18 is connected to each other input terminal. The respective outputs of each of the computer games) 65 and 66 are stored in an arithmetic storage device 70, and in this arithmetic storage device 70, drive command signals 71 to 7 for calculating the center position of the optical image and for alignment.
4 is output.

In this way, as shown in FIG.
If it can be detected by , then the center position 13' of the lid image 11! Since the center position as shown in FIG. 4(b) can be calculated by the il-arithmetic storage device 70, for example, the shape of the optical image 11 can be calculated in FIGS. 6(a) and (b).
) can eliminate this drawback.

That is, for example, the X-axis direction line of the photoelectric device 11 is made wider than the X-axis direction line. In this way, Figure 6 (a)
When each photoelectric element of the photoelectric array 25 is swept from top to bottom at 1, photoelectric element 32 and then photoelectric element 3 are swept from top to bottom.
3 and the level difference is detected, and by detecting the optical element 32 on the wide X-axis direction first, it can be determined that the center of the optical image 11 is positioned below the photoelectric array 25. . On the other hand, as shown in FIG. 6(b), the photoelectric element 43 located on the X-axis direction is detected earlier than the wide photoelectric element 42 located on the Y-axis direction, so that the center of the light ill is detected. It can be determined that the photoelectric array 25 is positioned above the photoelectric array 25.

-E Furthermore, since no moving parts are used as the detection device, the detection speed is increased and the lifetime reliability is greatly improved. In general, since the photoelectric array 25 inherently handles binary signals and is suitable for digital processing, detection accuracy and linearity are improved.

Furthermore, since a -dimensional photoelectric array of 1K to 2 bits can be easily obtained, the detection range can be expanded.

In this embodiment, one axis of the light r-elephant 11 is made particularly wide, or one axis arranged adjacently at an angle of 90 degrees from the center as shown in Fig. 7 may be made wide. It has the following effects.

In this embodiment, the inclination angle of the photoelectric array 25 is set to 45 degrees, but it may be set to, for example, 60' as shown in FIG. In this case, the X-axis direction line of the optical image 11 and
Even if the axial lines have the same width, the width of the photoelectric array partitioned by the optical r-elements 11 is different, so that the center position of the optical image 11 can be determined at one location. FIG. 9 is an explanatory diagram showing another embodiment of the invention, in which the photoelectric array 25 is arranged in four directions.
5 degrees, the XX-axis direction line shows an example using a uniform width light image 21, and the change in the spacing between the light receiving elements 27 and 28 when the light image is moved in the Y direction 21 with respect to the alignment of the light beam (in this case may be narrowed to 27.29) to determine the polarity with respect to the photoelectric array 25. For example, if the distance between the centers of the two light receiving elements 27 and 28 is A, the center of the optical image is X.

Both Y and Y are separated by A/2.

In each of the above-mentioned embodiments, the shape of the light beam is a cross, but the shape of the light ray may be in the shape of an 11 figure.

As is clear from the above description, the uninvented two-axis position detector is achieved by providing good detection accuracy and linearity.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing -fll of a conventional two-axis position detection device, Fig. 2 is an explanatory diagram showing the operation of the two-axis position detection device, and Fig. 3 is an illustration of an uninvented two-axis position detection device. An explanatory diagram showing an embodiment, FIG. 4 is a diagram showing the positional relationship between the optical image and the photoelectric array of the two-axis position detection device according to the present invention, and FIG. 5 is a configuration diagram of the circuit portion of the two-axis position detection device according to the invention. FIGS. 6 to 9 are explanatory diagrams showing other embodiments of the two-axis position detecting device according to the present invention, and are understood in terms of configuration diagrams showing optical image portions in %. 11... Optical image, 12... Expanded theory system, 15... Two-dimensional photoelectric detector, 16... Level discriminator, 17... Signal processing as well 1 Design 3 Figure vine S diagram (α ) (bn 1 v, 9 shares % 8th plan 9 M

Claims (1)

[Claims] 1. A device for optically detecting the position of a light image, comprising: a first means for enlarging the light image; a second means for detecting the one-dimensional spatial position of the enlarged light image; It comprises a third means for determining the level of the detected electric signal, and a fourth means for determining the center position of the detected optical image from the state of the binary signal string obtained by the means, and the optical image is Biaxial position detection, characterized in that the second means is a photoelectric array arranged at a constant angle with respect to the optical image, having two straight line parts parallel to the X-axis and the Y-axis. Device. 2. The biaxial position detection device according to claim 1, wherein the iM of the optical image and the width of the line portion are different in the X-axis direction and the Y-axis direction. 3. The biaxial position detection device according to claim 1, which uses a letter-shaped optical image.