JPH0317507A - Measuring apparatus for three-dimensional shape - Google Patents

Abstract

PURPOSE:To obtain a measuring apparatus being excellent in a measuring speed and resolution, easy to handle and of low cost by a construction wherein an optical slit having a function of rotation or a function of shift of a lattice pattern is provided in the direction of progress of a condenser lens. CONSTITUTION:For a lattice-shaped pattern irradiation element, a light source, a diffraction grating 1 and a condenser lens 2 are used by arranging them linearly sequentially. Moreover, a slit having a function of rotation of a lattice pattern or such a function of shift of the lattice pattern as to vary the lattice pattern is provided in the direction of progress of light of the condenser lens 2. A light proceeding from a focal plane forms an image analogous to the diffraction grating 1 on the conjugate plane of the diffraction grating 1. When a diffraction grating (b) having lattice spacing (d) is employed, the light is diffracted in a direction given by sin (u) = nl/d ((n) is the order and l a wavelength), and when only the light of the first order is passed by using the slit, a point image (c) on a spectral plane 3 turns to be (d). Thus, the lattice image can obtain twice as large resolutions as (b). Rotation of the lattice-shaped pattern and a change in the shape thereof can be controlled only by shifting or rotating the slit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of Industry-12) The present invention relates to a three-dimensional shape (recognition) device. More specifically, the present invention relates to a three-dimensional shape measuring device using a lattice pattern.

(Prior Art) In addition to the method using a case r pattern, methods used in three-dimensional shape measuring devices include a silhouette method, a light cutting method, a moiré topographic method, and a heptagonal method. (There are power type, autofocus type, etc.

3D shape measuring device i,? ，! When classified by the performance of the device, it is high resolution, but il/! lllLong measurement time and ■, Low resolution and 3; 1 Short measurement time■,
Both the resolution and the required measurement time can be divided into two types: (1) and (2) which are intermediate between (2) and (2).

High resolution, but measurement required +1. '7 The triangulation method and autofocus method are the measurement methods with long intervals, and the silhouette method is the one with low resolution and short measurement time. As an example, it can speed up the case r pattern projection method, moiré topography method, and light cutting method.

Regarding the measurement methods for ■, ■, and ■, Qj. Explain.

As an example of (2), we will explain the three-way, corner-i1111 chewing method.

Two corners? In the Illi fd method, if you measure the angle to the measurement point at both ends of the line whose length is known, you can accurately know the distance from the l1 chord constant plj to the measurement point, and from the distance variation you can calculate the three-dimensional Shape variation of submicron 11
It can be found in 14th place. However, the measured degree is 1;
Li1-. In order to do this, it is necessary to increase the length of the line.・1F, and the handling is complicated.

As an example of (2), a single silhouette type will be explained.

The silhouette type one type is a method that irradiates the object with 11 (11) beams of light and observes the silhouette of the object to recognize the three-dimensional object, and although high-speed measurement is possible, the measurement resolution is 1.
It requires a mechanism to rotate and move the test object.

As an example of (2), the optical cutting method will be explained.

The optical cutting method uses a scanner to scan ten thousand laser beams in a straight line, turning a linear spot into a stationary object! ! (This is a method that recognizes the three-dimensional shape of an object by emitting a single beam and measuring the position of this spot using a Bojin Tan sensor or a dedicated television camera. Although it is possible to obtain a resolution of several microns, it is possible to obtain a resolution of several microns.
A total of 7111 moving parts are required, and a total of 7111
1.Illustrate the disadvantage of having to spend a lot of time hearing.

(Problem to be Solved by the Invention) As mentioned above, there are various methods used in three-dimensional shape measuring devices, but all of the force methods have problems with measurement speed, measurement, one-time measurement, and shank placement. Three-dimensional shape 7 satisfies all conditions, with problems mainly related to simplification of handling and equipment price.
The realization of the 1111 fixed cost is Tama.

In view of this situation, the inventor has conducted extensive research and found that
We have arrived at our next invention.

(Means for Solving the Problems) The present invention irradiates a test object with a grid pattern using a light source such as a laser and images it from different directions. =
1i In the three-dimensional shape measurement device that measures the three-dimensional shape of the object to be tested, a raku-shaped pattern! ! The 6-ray part has a light source and a condenser lens linearly arranged in sequence, and furthermore, the 6-ray part has a light source and a condenser lens arranged linearly in sequence, and furthermore,
This is a three-dimensional shape measuring device characterized in that an optical slider is arranged in the il to perform a 101 rotation function of a case γ pattern or a movement function of a lattice pattern such as converting 19A between Raku r patterns. .

The light source in the present invention is not particularly specified, but a gas laser, a 14 conductor laser, a dye laser, a solid laser, a white light source, a white light source, etc. can be used.

In the present invention, the isoptative r can be either a reflection +77 type or a transmission type, but a transmission type is preferable.

Although the material and structure of the optical slit in the present invention are not particularly limited, it is preferable that the surface of the optical slit be coated with a special paint or fiber to reduce diffused reflection of light.

The origin of the present invention will be explained with reference to FIG.

As is clear from (a), when light enters the homogeneous lattice from a direction parallel to the optical axis of the lens, the light is sin(u):nl/
ri'il analysis is performed on the one given by d (n is the order, 1 is the wavelength, and d is the lattice spacing).

This light is the focal point of the lens (spectral plane) + (i, [l
=0, n=+/ -is A point image group corresponding to n=10/-2- is generated (e, h).

Furthermore, j. The light that travels from the li point produces an image similar to the same analytical lattice at the point L (b).
When using the isotrotic case f'(b), the spectrum becomes (C
) is a point image, but using an optical slit and transmitting only the primary light, the 1 o'clock (d) and case r images are (e),
It is possible to obtain twice the resolution compared to (b).

Now, the complex vibrational transmission of the isotrotic r- ='f<T. But (1
) is the apposition case Y of the iE sinusoidal cap.

T. =1+cos (2πSoξ) (1) So: Lattice frequency ξ: Isoprotic case = r + standard Equation (1) can be replaced with (2).

T- = 1 + 0.5exp (2 w Soξ) +
0.5exp(-2πSoξ) Each term in equation (2) corresponds to a 0th-order spectrum and a 1st-order spectrum.

The isometric grid image will be represented by IT,+2.

l T. l 2 = 3/2 + 2cos2πSo
ξ+0. 5 cos4 πSn ξ When the 0th-order spectrum is blocked by an optical filter or the like, the complex amplitude transmittance T, becomes equation (3).

T, = cos (2πSo ξ) (3) The isometric r image is I
It will be expressed as T, +2.

l↑, I2 = 1/2 + 0.5cos4πSo ξ Therefore, when the 0th order spectrum is blocked by an optical slit etc., the fundamental frequency S of the diffraction grating r. We will obtain an isoanalytic case image with a period twice that of .

Also, if you use a grid like the one in (f), you can get (h)
A spectrum like (i) is obtained, but if an optical slit that leaves only the oblique direction is used, the case r image becomes (
g) It is possible to obtain a grating spectrum and an image of 111:.

According to the present invention, the rotation and deformation of the case Y pattern in order to increase resolution or measurement speed can be achieved by moving the optical slit, I! With only j1 rotation; i, II glI is rIf function, and the grating pattern projection mechanism can be simplified or omitted i+}, and a complicated adjustment mechanism is not required at all.

Further, since the grating pattern is changed using an optical effect, it is possible to obtain a stable and highly accurate change in the case r pattern compared to a case where a mechanical mechanism is used.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these in any way.

(Example) Examples will be described below based on the drawings.

Using the three-dimensional shape measurement equipment shown in Figure 2, a diameter of 1
Performing three-dimensional shape recognition of a spherical object of 0 0 mi IJ,
Good results were obtained with a resolution of 1 micron and a measurement time of 30 seconds.

A helium-neon laser manufactured by IJ Wasotho with an optical output of 50 mm was used as the light source of the apparatus. lLi + lattice has a groove spacing of 1
Micron, the size! A piece with a length of 50 mm and a length of 50 mm was used.

As an optical slit, I used a black aluminum plate with holes drilled at locations corresponding to the spectral point images.

(Effects of the Invention) As described above, the three-dimensional shape measuring device of the present invention is /! I'll give you an advantage in terms of constant speed, resolution, and ease of equipment handling.
It was found that it has special Pt properties such as excellent productivity, low cost, and excellent environmental performance.

[Brief explanation of drawings]

FIG. 1 is an original raccoon diagram of the present invention. FIG. 2 is a schematic diagram of the apparatus of the present invention. Early 11!1 (Q) 1 ■ f'r turbidity ÷ 2 Enter the lens 3゛ Sveftle surface 4.　o＊＃J{& Patent distributor: Toyobo Co., Ltd. (e) (f) (9) (h) (1) 2 figure

Claims (1)

[Claims] (1) In a three-dimensional shape measuring device that measures the three-dimensional shape of a test object by irradiating the test object with a grid pattern using a light source such as a laser and capturing images from different directions, the grid pattern The irradiation section has a light source, a diffraction grating, and a condenser lens linearly arranged in sequence, and a grating pattern that has a grating pattern rotation function or a grating pattern interval that changes the grating pattern interval in the light traveling direction of the condenser lens. A three-dimensional shape measuring device characterized by having an optical slit having a moving function.