The fully automatic stress meter is a dimensional quantitative measurement device that fully automatically detects the optical path difference and slow axis direction inside a transparent object with stress and birefringence. At present, the quantitative measurement of stress and birefringence is mainly based on the Sennamon method instrument observed with the naked eye. Recently, the semi-automatic Sennamon method developed by our company, which only requires manual rotation of the analyzer, has become popular.
The Sennamon method is a detection method that quantitatively detects the optical path difference by rotating the analyzer to change the measurement part from the brightest to the darkest state. However, it is always a naked-eye observation type, and the brightness judgment may vary depending on the measurement environment and the person measuring it. In addition, the accuracy of semi-automatic measurement is improved compared to naked eye observation, but the measurement location is limited to a specific part of the image. The Sennamon method cannot detect the direction of the slow axis and can only be inferred by referring to the photochromic method. In addition, when observing two-dimensional distribution, it is necessary to draw images of the results of multiple measurements over a long period of time.
This device places the sample on a circular polarizing plate composed of a linear polarizing plate and a wavelength plate, and the measurement can be started directly. Therefore, there is no difference between experienced users and beginners, and they can easily perform quantitative measurements of optical path difference and slow axis direction. In addition, not only specific parts can be measured, but also every pixel unit can be measured using the built-in camera. Therefore, the optical path difference and slow axis direction can display a dimensional image on the display, and the distribution status can also be seen at a glance.
Because it is easy to record measurement data and observation images by connecting it to a computer.
The light source uses a high-brightness lamp, which has a long life and saves electricity, so the time and operating costs of replacing the light source are reduced.
Measurement principle
The measurement method adopts the method of fixing the circular polarizing plate and rotating the analyzer.
The light passes through the linear polarization +/wavelength plate and becomes circularly polarized light. When a stressed sample is placed, an optical path difference is generated between the slow axis and fast axis of birefringence and becomes elliptically polarized light. Then rotate the analyzer, and within the elliptically polarized light, the polarized light transmission axis and parallel light pass through in the form of linearly polarized light. At this time, it can be seen that the light intensity passing through the analyzer changes according to the optical path difference and slow axis direction as the angle of the analyzer changes. The fully automatic stress meter measures four predetermined angles and takes pictures with a camera. The polarization state (circularity and ellipse slope) is obtained from the light intensity at each angle.
Then, it is detected whether the sample is placed, and the size of the optical path difference and the direction of the slow axis are calculated from the differences in each polarization state.
Product Specifications
Model
Appearance Dimensions (Main Body)
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Weight (Main Body)
Circular Polarizing Plate Dimensions
ⅹ
Measuring spatial height
Detection method
Rotating analyzer method
Setting wavelength
Repeated measurement accuracy
(standard deviation)
Measurement range
ⅹ
Effective pixels
ⅹ
Light source
High intensity
Power supply
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Composition
Measurement body wire type
Accessories
Main body cover
Correspondence
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Fully automatic polarizing stress meter PTC-9