JPS5855830A - Measuring apparatus of surface stress - Google Patents

Abstract

PURPOSE:To measure surface stress accurately, by a method wherein a laser beam is excited to run in parallel with a surface of an object to be measured, and surface stress is measured by utilizing a senarmount compensator according to the difference of photoelastic beam pathes arisen in the emitted beam. CONSTITUTION:A laser beam 8 emitted from a light source 29 is reflected at a prism 38 and reached to a glaze layer A of an object B to be measured. The beam further advances in the layer A, and then, a part of the beam passes through an exit prism 26, and through a quarter wave plate 43 which forms a senarmount compensator with a polarizing plate 32B, and is detected by a photodetector plate 47. When there is stress, it is observed as the contracted part 316 in a streak of light 313 by rotating the plate 47. The stress can be measured on the basis of the Senarmount law, by measuring the shift of the shadowed part 311 which is shifted as the plate 47 rotates.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to #1 an improvement in a surface stress measuring device capable of non-destructively measuring the surface stress of products decorated with vitreous glazes and stones such as porcelain products and ceramic products. .

The above products are coated with two glazes on the surface of the base to strengthen the surface. However, there is a slight difference in thermal expansion between the base and the glaze, and this can be completely ignored. However, it is impossible with current technology to approximate the same as possible, so it is inevitable that some differences will occur.Feature 5: The surface of the above glaze during firing Stress is generated in the parallel surface direction.The absolute value of this stress is proportional to the magnitude of the expansion difference, and whether the stress is compressive or tensile is determined by the magnitude of the difference in thermal expansion between the glaze and the base.

If the surface stress of the glaze is tension, the glaze either spontaneously cracks, cracks over time, or easily cracks due to external force or impact, which is inconvenient for practical use. Otherwise, the product value will be lost.

If the surface stress is a large compressive force, the glaze layer is likely to spontaneously peel off.

If the surface stress is an appropriate amount of compressive force, #1 wax or ceramic products will be strong both mechanically and chemically, and have the desirable effects of improving yield during manufacturing and improving durability during use. Therefore, during production, special attention is paid to the combination of the substrate and glaze so that the glaze has an appropriate compressive force C2.

However, since some differences occur in the above, it is necessary to control this manufacturing process, and in order to be able to perform this control non-destructively, the inventor first made repeated studies to improve the sensitivity of surface measurement. It is something. In other words, the above-mentioned surface stress meter has a sensitivity (accuracy) of about 1/-, which is equivalent to enamel, industrial use, or some industrial use.
C2 can be effectively applied when there is a large narrow surface stress in the ceramics used in the range of 5 to 20 to 4/-, but for example, in high-quality tableware where measurement accuracy of o, ib/- is required. may be difficult to measure.

The present invention excites a laser beam that travels parallel to the surface of the object to be measured, extracts this beam, and extracts this emitted beam.
The present invention provides a surface stress measurement device that uses the principle of the Senarmont corrector to improve the accuracy of measuring the difference in photoelastic beam path that occurs between two photoelastic beam paths.

FIG. 1 is an explanatory diagram of the principle of the surface stress measuring device of the present invention, and shows a surface I of a substrate (1): a glaze layer (2) is formed. The surface of this glaze layer (81ij is a rough surface). An entrance prism (4) and a transparent plate (5) made of optical glass having a higher refractive index than this scrap are placed on the surface of this glaze layer. An exit prism (6) having the same characteristics as the entrance prism (4) is attached to each of the prisms (4).
) and (6) and the surface of the glaze layer (2) (C2) is injected with a liquid (7) whose refractive index is similar to that of the prism. is used (- to aid in optical contact).

The laser beam (81ti
The polarizing plate (1' in Fig. 1 is not shown and shown in 32b in Fig. 2) has already produced 6-linearly polarized light, which is focused at approximately the surface of the glaze layer (111) and the incident point (j). It is projected so as to form a total reflection critical angle (ψ0) with respect to the vertical line at c.

The plane of polarization is 6
It's two. In addition, a part of the beam emitted into the glaze layer (2) is propagated along the chord of this surface (8), becomes a beam +121 Q81, etc., and returns to the surface (8).
The emitted beam (to) (b) from each injection point 541 (2))
and is radiated.

For example, if we assume that there is stress inside the glaze layer (2) and that the stress does not depend on the depth C2 from the surface (8), then the linearly polarized light of the incident beam (8) is After entering the layer (2), it separates into two linearly polarized components that vibrate in parallel and perpendicular directions to the surface of the layer (2), respectively, and due to the photoelastic effect due to stress, an optical path difference between the two components (C-beam) occurs. become. If this optical path difference is R, then the photoelasticity formula (from 2), if the photoelastic constant of the glaze layer is C, then F
The optical path difference (R) caused by the beam (2) in the glaze layer with stress = c y x (distance between the incident point (9) and the exit point).

Optical path difference (R) generated in the beam within the glaze layer = o
v x (distance II between the entrance point (9) and the exit point (b)). These optical path differences (R) are the emitted light (to)
(1'F)C is stored and measured by photoelastic means.

As a result of this measurement, the difference in optical path difference (R) between the beam (2) and the α feed is determined by cyx [(incidence point (9) and exit point (
) - (distance between the incident point (9) and the exit point)]
It is. If the distance between the incident point (9) and the injection points (b) and (to) is sufficiently l2 compared to the radius of curvature l2 of the surface (8) of the glaze layer, then the value in the curly brackets in the above equation indicates injection. It can be approximated that the distance between the point ) and the exit point (to) are equal.

Therefore, the difference in optical path difference between the beams (2) and αB) is 0.
FX (distance of the injection point (2) house)) is established, and F can be calculated.

The present invention is based on the five principles and has completed the measurement of the optical path difference using a Senarmont compensator, and an embodiment thereof will be described in detail below with reference to FIG. 2.

The base plate is a support base that supports the entire body, and is provided with fixed feet (1) and movable feet that can be adjusted horizontally.

A prism support frame fixed to a part of the substrate (company) holds an entrance prism (7) and an exit prism (2) with a light shielding plate at the center thereof. Each of the above-mentioned frisms has a right-angled triangular shape, and is configured so that the beam passes through the slope and the right-angled short side serves as the measurement surface that comes into contact with the object to be measured. Projection p" structure cn is support □□□
) and laser light source-1 and adjustable second reflective prism ■)
The laser light source is fixed parallel to the support ζ, and the first reflecting prism is fixed to the support @) via the support i8]). Further, part f2 of the laser light source is provided with an emission part for emitting a laser beam, and inside this emission part there is a convex lens A for optically focusing the laser beam and a polarizing plate B. It is attached. Further C
The first reflective prism example has a right-angled triangular right-angled surface facing the above-mentioned emission part, and its slope (2) so as to reflect and convert the above-mentioned laser beam. The screw e@C2 allows the inclination of the support (to) to be changed freely by 1''. Rotatable C - pivoted to the fulcrum -
Center 1: The inclination angle of the support body can be adjusted.

ml is a prism fixing body that fixes the second reflecting prism, and a part of the substrate (f) is rotatable (g), and a part of it is pivoted (I: F).
A movable transmission element (i) consisting of a rod is fixed, and this element is a long rod whose free end is arranged along the base 1 and the outer surface of the eccentric cam which rotates eccentrically. It is shaped like i2 so that it changes up and down C2 upon contact. Each of the eccentric cams is fixed to a part of the board, which is rotatable. The movable transmission element is moved (up and down) in the direction of the arrow by rotating the eccentric cam, so that the first reflecting prism can be finely adjusted. -) is a microscope whose tip is a part of the above-mentioned substrate -C which can be rotated freely.
When pivotally mounted, the opening of the above injection prism (m)
The slopes of the microscope (two facing each other) are built into this microscope cabinet, as well as an objective lens, a polarizing plate, a quarter-wave plate, and an eyepiece.In this case, a quarter-wave plate is installed. 1) and analyzer plate -) [explained below] are polarizing plate 1321
The optical axes are arranged to coincide with each other so as to form a Senarmont compensator in photoelasticity. If necessary, a scale may be interposed at the position where the real image is generated by the objective lens zone. In addition, an angle scale plate is attached opposite the eyepiece, and an analyzer plate (WI) is rotatably fixed, and an adjustment mechanism for adjusting the inclination angle between the microscopes is attached to reduce the surface stress. The measuring device is configured with i'-.

The second arc measurement operation will be explained with reference to FIGS. 2 to 4.

Fig. 3 shows a situation in which a real image of the surface to be inspected A (the second glaze layer in Fig. 2) is observed through the eyepiece 1441, and the lower dark area (311) in Fig. It is a statue. Further, a ray (313) formed by the light emitted from the trailing edge (312) of this illumination image has a narrow band shape.

The direction of travel of the light is indicated by an arrow (314), and if a scale interval is attached, a scale (315) is shown. The actual length on the glaze layer surface A can be measured using this scale (315), and it is convenient to determine it at any time by calibrating it.

That is, as shown in FIG.
The light is condensed by I-, polarized by polarizing plate-B, and is reflected by colliding with the reflecting prism (1101).This reflected beam advances to the second reflecting prism (1101), where it is further
= Two people are reflected and enter the incident prism inclination C. The laser beam that has passed through this incident prism passes through a liquid that improves optical contact, and then passes through the glaze layer surface A of the object B.
As shown in Fig. 1, the glaze moves through the glaze layer, and a part of it passes through the exit prism □ and passes through the microscope's objective lens - quarter-wave plate 11 and eyepiece lens. It can be detected as shown in FIG.

If there is no stress in the glaze or chemical layer A, when the analyzer plate is rotated, the overall brightness of the striations (313) changes uniformly, and the light becomes brighter or darker.

On the other hand, when glaze layer AC stress occurs, analysis IIi,
When rotating w), a ray (313) appears as shown in Figure 4.
A very small constricted part (316) can be observed in a part of the area.

Further, the rotation angle of the analyzer plate is calculated by reading it using the scale provided on the second side of the angle scale plate-C.

In other words, the dark area (311) is determined by the rotation θ(
○ Moves from SL2 By measuring the movement of this dark part (311), the stress measurement can be calculated as follows.

In the above explanation, polarizing plates gz are placed before and after the quarter wavelength plate.
Although BM was used, if the beam used, for example, a laser beam, has a polarized component, it is also possible to configure the Senarmont compensator with one polarizing plate.

Rotation θ6 of the above analyzer plate q) = According, the dark area (311) is A
Assuming that the distance is moved by m, the difference in the optical path difference at both ends of the moving distance C2 is given by the well-known formula in the Senarmont method. For example, He −H
Using e-laser light (wavelength 633 nm), when the analyzer plate is rotated 3 degrees, the dark area moves by 0.5 ffi, and the photoelastic constant of the glaze is 2. s (nm/”)/(V-
), the difference in optical path difference is 3°633nm
f/eIi) XFXo, 5” to F = B, 5t4/ai = 0.085 noodles/-
Therefore, it can be seen that even emergency C: low stress can be detected.

The surface stress measuring device of the present invention is constructed as described above, and therefore has the following effects.

Using a laser light source, the laser beam emitted from this light source excites a beam that runs parallel to the surface of the object to be measured, and when this beam is emitted, the photoelasticity generated in the emitted beam is By configuring a Senarmont compensator consisting of the polarizing plate 9321B provided with the beam path and a quarter wavelength plate for the optical path difference, the image can be projected onto the analyzer plate with extremely high sensitivity.

In this way (2) The image taken with high sensitivity rotates the analyzer plate ≦ 2. Therefore, the stress on the surface of the object to be measured can be easily determined, read it on the angle scale plate, and calculate it using the Senarmont method. The stress is calculated by

As described above, by simply bringing the surface of the object to be measured C2 into contact with the inclination prism 1 of the device of the present invention and the bottom surface 2 of the exit prism, it is possible to measure the stress of each individual object without breaking the WL of the object. For example, if a high-sensitivity image is used in conjunction with a video sensor, it can be used to measure the quality of the process, such as in the manufacturing process of high-grade glass, making it possible to produce high-quality glass.

In addition, the laser beam emitted from the light source can be adjusted by the reflecting prism 131Jl&#l2.
This and 1i1i1 are also free C= by rotation of eccentric cam etc.
It is also possible to make fine adjustments. That is, due to the synergy between the movable transmission element 1891, which is a long rod, and the eccentric cam chrysanthemum, the reflection prism a91 attached to the tip thereof can be adjusted extremely finely.

In the above description, an embodiment in which the entrance and exit prisms and the light-transmitting plate are integrated is used, but even if they are configured to be directly separated from each other, the effect is the same.

The optical system for laser light incidence and the mechanism C2 for adjusting and fixing the light incidence angle and the tilt angle of the microscope can also be different from those described above. Furthermore, the arrangement order of the objective lens, eye lens, quarter-wave plate, and analyzer plate of a microscope can also cause several types of deformation that disrupt the function of Senarmont's compensator. Also,
Since porcelain and ceramic products often have curved surfaces, the above advantages are further enhanced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining the principle of the p-plane stress measuring device of the present invention, FIG. 2 is a side view showing a state in which surface stress is being measured using the surface stress measuring device of the present invention, and FIG. Figures 3 and 4 are enlarged views of the microscopes that detect the measurement state in Figure 3 using an analyzer plate (-). (2) Substrate (Transfer) 1... Prism support frame −
... Light shielding plate a! 5)...Incidence prism @J...
Ejection prism head...laser light source))...first reflecting prism uB, 14g1...polarizing plate -...adjustment screw-...@2 reflecting prism...movable transmission element...・fig Aligning cam □□□・・・Objective lens-
... Quarter wave plate ■ ... Eyepiece - ... Angle scale plate -j ... Analyzer board Agent Patent attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2 Figure 3 figure

Claims (1)

[Claims] A beam projection mechanism having a laser light source, an optical system for condensing the laser beam from this light source, and a polarizing plate, and a beam projection mechanism having ≦2 paths for the laser beam emitted from the projection mechanism and converting the emission direction thereof. OL several reflective prisms, an incident prism that receives the above laser beam converted by the reflective prisms and adjusts the beam to be incident on the object to be measured C at a constant angle, and a lever is installed in the vicinity of the incident prism. An exit prism for detecting the reflected beam from the object to be measured; The surface stress 1111 comprises a portion farther from the light source side than the one-wavelength plate (and another polarizing plate), and constitutes a Senarmont compensator using the plurality of polarizing plates and the quarter-wave plate. Fixed device.