JPS59197809A - Interference measuring device - Google Patents

Abstract

PURPOSE:To enable calibration of the positional deviation of a measuring optical system so that not only the flatness of optical parts but also the squareness of two orthotomic surfaces and the parallelism between the surfaces can be measured by providing a rectangular prism to the longitudinal end of an optical part having the two continuous orthotomic surfaces which are objects to be measured. CONSTITUTION:A roof mirror array 4 is held on a stage 28. A rectangular prism 29 is fixed to the longitudinal end of the array 4 on the stage 28. The stage 28 is moved in a way that measuring light 14 falls onto one surface of the prism 29, then only the shutter 18 is opened to align the spot position on a position sensor 27 to the spot position by reference light 15. The point where both positions coincide is determined as the turning origin of a mechanism for turning the stage 28 around the X-axis and Y-axis. Calibration is made and the stage 28 is moved again until the light 14 falls onto the measuring surface of the mirror 4, by which the alignment to each measuring surface is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an interference measurement device for an optical component having two continuous orthogonal planes in the longitudinal direction, such as a roof mirror array.

(Prior Art) A roof mirror array is used in combination with a lens array as an imaging device for a copying machine or the like. FIG. 1 schematically shows an example of an imaging device using one such roof mirror array. The image on the original surface 1 is reflected by one reflective surface of the right-angle mirror 2 for optical path splitting, and
The light passes through a lens array 3 in which a large number of lenses are arranged along the longitudinal direction, and enters a roof mirror array 4. The roof mirror array 4 has two perpendicular planes in its longitudinal direction, the number of which corresponds to the number of lenses, and reflects the light from the lens array 3 to pass through the mirror array 3 again.

This light is then reflected by the other reflective surface of the right-angle mirror 2, and an image of the document surface 1 is formed on the photoreceptor surface 5.

Such a roof mirror array 4 is required to have strict accuracy in the flatness of its reflecting surface, the perpendicularity of two orthogonal planes, the parallelism between the facing tiles, and the like. Conventional interference measuring devices can only measure one plane in one measurement, and it is impossible to measure the perpendicularity or parallelism between two planes.

(Object of the Invention) The object of the present invention is to use the alignment mechanism of an interferometric measuring device to measure not only the flatness of an optical component such as a mirror array having two orthogonal continuous planes, but also the alignment mechanism of an interferometric measuring device. An object of the present invention is to provide an improved interference measuring device that can also measure the circularity of a plane and the parallelism between face tiles.

The configuration of this invention will be described above with reference to FIG. 2, which shows one embodiment of this invention.

(Structure of the Invention) In FIG. 2, the laser beam emitted from the laser tube 10 is
After passing through lenses 11 and 12 and being adjusted to an appropriate diameter, a beam splitter 13 separates the measuring beam 14 and reference beam 15.
It can be divided into The measurement light 14 further includes a beam splitter,
Divided into two by ri 16, Sosai Shisoha, Nya, ri 1
7 and 18, is reflected by the mirror 19 and 20, and is then reflected by the measurement surface of the Dunno mirror array 4, and returns along the path it just came. On the other hand, the reference light 15 passes through the shutter 21, is reflected by the reference surface 22, and returns along the same optical path. The returned measurement light 14 and reference light 15 interfere with each other and form beams.

The video camera 25 passes through the lens 23 and the lens 24.
observed with the naked eye. The other beam split by the beam splitter 23 passes through the lens 26 and enters the position sensor 27 .

The roof mirror array 4 is held on a mounting base 28. A right angle prism 29 is fixed to the longitudinal end of the roof mirror array 4 on the installation base 28.

The installation stand 28 is movable in the longitudinal direction of the roof mirror array 4, and is at least parallel to this longitudinal direction.
It is rotatable between the shaft and the Y-axis perpendicular to this.

Now, open only the shutter 21 and close the other shutters 17°1.
8, the reference light 15 reflected by the beam splitter 23 forms a spot image on the position sensor 27 by the lens 26. The position sensor 27 can read the spot position at this time.

Similarly, if only the shutter 17 or 18 is opened and the others are closed, the corresponding spot images of the measuring light 14 will be
An image is formed on the position sensor 27. Therefore, if the measurement surface is tilted, the measurement light 14 entering the lens 26 will have a certain angle with respect to the reference light 15, so that the spot position generated on the position sensor 27 will be different from the reference light 15. It deviates from what it was at the time. Therefore, in order to generate interference fringes, it is necessary to tilt and align the measurement surface of the roof mirror 4 so as to eliminate this deviation.

Therefore, the installation base 28 is moved so that the constant light beam 14 hits one surface of the prism 29, and alignment is performed by opening only the shutter 18 as shown in FIG. is made to coincide with the spot position of the reference light 15. And this match @
is defined as the rotation origin of the mechanism for rotating around the installation table 28'kX-axis and The spot position by the light 14 is measured. This spot position represents the perpendicularity accuracy of the optical system consisting of members from the beam splitter 16 to the mirror 19. If so, the spot position of and should match the rotation origin in -1-, but if these do not match, this member 16.1
7. This means that the optical system consisting of 19 parts is not circular. Therefore, calibration is performed so that they match. This calibration must always be kept in mind when measuring the roundness of the roof mirror 4. When this calibration work is completed, the installation table 28 is moved again and the measurement light 14 is
- Bring it into contact with the measurement surface of the mirror 4, and perform alignment for each measurement surface using the same procedure as described above.

Each measurement value is represented by two values, θX and 0Y.

As shown in FIG. 4, it is assumed that the vector AB has been measured during calibration using the prism 29. Point A is determined by the alignment when the shutter 18 is opened, and point B is determined by the alignment when the shutter 17 is opened. Next, the shutter 18 is opened to align the mirror surface to point C, and the shutter 17 is opened to align the point to =CE. Similarly, the mirror surfaces are measured one after another. Therefore, the roundness of the two adjacent holes jCF
It is possible to measure not only 21 but also the positional relationship between mirror surfaces, that is, parallelism and circularity.

(Effects of the Invention) As described above, according to the interference measurement device of the present invention, a right angle prism is provided at the longitudinal end of the optical component having two continuous orthogonal planes, which is the object to be measured. In addition to knowing the rotational origin of the rotation, it is also possible to calibrate the positional deviation of the optical system, and it is possible to calibrate not only the flatness of optical components, but also the circularity of two orthogonal planes and the parallelism between the planar tiles. can also be measured.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an example of an imaging device equipped with a roof mirror array, and FIG. 2 is an interference 411 according to the present invention.
FIG. 3 is a diagram illustrating the operation of the device shown in FIG. 2, and FIG. 4 is a diagram illustrating the measurement results of the interference measuring device according to the present invention. 4... Roof mirror array, 10... Laser tube, 13
゜16.23...beam splitter, 17.18.21
... Shutter, 22 ... Reference plane, 25 ... Video camera, 27 ... Position sensor, 28 ... Installation stand, 29
...Right angle prism.

Claims (1)

[Claims] An interference measuring device for an optical component having two continuous orthogonal planes in the longitudinal direction, comprising means for moving the optical component in the longitudinal direction, and a means for moving the optical component at least in the longitudinal direction and in a direction perpendicular thereto. 1. a right angle prism juxtaposed at the longitudinal end of the optical component; An interference measuring device comprising (+iii) an optical system capable of independently measuring two perpendicular planes of the optical component and the right angle prism.