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    Home > Active Ingredient News > Drugs Articles > Instructions for use of the polarizing stress meter

    Instructions for use of the polarizing stress meter

    • Last Update: 2022-10-10
    • Source: Internet
    • Author: User
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    The glass product stress checker is an instrument that applies the principle of polarized light interference to check the internal stress of glass or the birefringence effect of crystals
    .

    Since the instrument is equipped with a sensitive color plate and applies the 1/4 wave plate compensation method, the instrument can not only qualitatively or semi-quantitatively measure the internal stress of the glass according to the interference color sequence in the polarized field, but also accurately and quantitatively measure the internal stress of the glass.
    Internal stress value
    .

    Testing Equipment: SG-03 Polarizing Stress Meter This instrument is suitable for optical instrument factories, glass factories, glass products factories and laboratories.
    It is used to measure the stress value of various glass products, optical glass, transparent plastic products and other optical materials
    .

    This product has been strictly debugged before leaving the factory and complies with relevant domestic and foreign standards, including: l GB/T 4545 "Inspection Method for Internal Stress of Glass Bottles and Jars" l GB/T 12415 "Internal Stress Test Method for Medicinal Glass Containers" l GB /T 15726 "Internal Stress Test Method for Glass Instruments" l JC/T 655 "Internal Stress Test Method for Quartz Glass Products" l YBB00162003 "National Standard Test Methods for Internal Stress of Pharmaceutical Packaging Containers (Materials)" l ASTM C148 (Standard Test Methods for Polariscopic Examination of Glass Containers) (Test Method for Polariscope Inspection of Glass Containers) 1 Technical Features Compared with the traditional dial-type stress meter and digital display stress meter, SG-03 has made targeted improvements to improve the measurement accuracy and application experience.
    Advanced features such as high measurement accuracy, no need for zero calibration and green energy saving: l High-precision measurement: This product uses a high-precision absolute angle encoder for measurement, and the measurement accuracy is better than 2.
    0nm
    .

    l Dual-value display on the LED display: The product display window adopts a high-definition LED display, which can simultaneously display the measurement angle and the optical path difference value.
    The user can intuitively obtain the required data, making the measurement intuitive and easy to read
    .

    l Dark field does not need to be calibrated: This product has been accurately calibrated for dark field before leaving the factory
    .

    Due to the use of an absolute encoder, the dark field of the polarized field is always at the zero angle point, so there is no need for users to calibrate the zero point, avoiding the error caused by artificial calibration of the dark field
    .

    l Green energy saving: This product adopts a more energy-saving and environmentally friendly LED light source, which saves more than 80% energy compared with traditional light sources
    .

     Main technical parameters Measurement accuracy ± 2nm complex lingwu difference ± 2nm optical path difference indication value 0.
    1nm angle indication 0.
    1° polarization field diameter 150mm field of view light brightness > 120cd/m2 analyzer rotation angle 360° (± 180°) polarization field Spacing adjustment range 50-250mm Light source LED Color temperature 3500K Power <8W Voltage AV 220V 50Hz Total weight Measurement principle: qualitative measurement principle There will be interference colors, and a certain interference color corresponds to a certain birefringence optical path difference, and the relationship is shown in Table (1)
    .

    The full-wave plate located between the polarizer and the analyzer has a birefringent optical path difference of 565 nanometers (nm).
    From Table (1), it can be found that the interference color in the field of view is purple
    .

    If a test piece is added between the crossed polarizers in addition to the full-wave plate, the combined path difference δ' of the two will be larger or smaller than 565 nm, and the interference color will change accordingly
    .

    According to the interference color look-up table (1), the combined optical path difference δ′ value can be obtained, and the optical path difference δ of the additional specimen can be marked by the following formula: 1.
    When the fast axis of the additional specimen and the fast axis of the full-wave plate are mutually When parallel: δ= δ′- 565 (nm) ———————— (Formula ①) 2.
    When the fast axis of the additional specimen and the slow axis of the full-wave plate are parallel to each other: δ= 565 - δ′ (nanometer) ————————— (Formula ②) (2) Stressed glass specimens are also birefringent substances.
    Putting such specimens into the stress inspection optical path will also cause interference colors.
    The change is the same as the case where the additional specimen is placed in the optical path as mentioned above, but it is only because the stress of the glass specimen is not uniformly distributed
    .

    Therefore, the birefringence optical path difference of each point of the specimen is also inconsistent, and the result is that the interference color changes of each point in the field of view are also different
    .

    However, for a certain point in the test piece, the optical path difference δ can also be obtained according to the above method [check table (1) to obtain δ′ and then use formula ①② to calculate]
    .

    (3) When the birefringence optical path difference of the tested glass specimen is large (for example, the optical path difference is greater than 300 nanometers); the measurement can be performed even without a full-wave plate
    .

    At this time, the test piece is placed between the orthogonal polarizer and the analyzer, and the obvious interference color can be seen.
    According to Table (1), the optical path difference value of the test piece can be found out
    .

    5 Measurement method 5.
    1 Before measurement 1.
    According to the length of the product to be measured, adjust the distance between the analyzer and the polarizer
    .

    Loosen the locking screw (16) and pull the guide rod (18) to move up and down, and lock it securely after setting the distance
    .

    2.
    Insert the external power plug into 220V 50Hz AC power for use, please ensure the safety of electricity use
    .

    3.
    Press the power switch (12)
    .

    At this time, the light source of the instrument is turned on, and the numerical display window displays relevant data
    .

    5.
    2 Qualitative Measurement 1.
    Note: Before qualitative measurement, it is necessary to place the full wave plate (3) in the field of view by rotating the wave plate switching knob (4)
    .

    Rotate the analyzer holder (1) so that the numerical value display window (10) displays the angle as 0 (and the optical path difference also displays as 0)
    .

    At this time, the field of view is observed through the analyzer (2), and the field of view is purple
    .

    The optical path of this instrument has been adjusted correctly before leaving the factory
    .

    2.
    Put the test piece into the interference field of view, observe the entire surface of the test piece through the analyzer, and qualitatively judge the annealing quality according to the interference color
    .

    If the test piece is placed in the optical path, the color of the field of view is basically unchanged (still purple-red) or only slightly changed (from dark red to purple), indicating that the annealing quality is good
    .

    If the interference color changes greatly in some parts of the test piece (for example, green or yellow), the annealing quality is poor
    .

    3.
    If it is necessary to carry out a semi-quantitative test, you can rotate the test piece around the optical axis of the instrument while observing the change of the interference color to find out a part of the test piece where the interference color changes greatly, and determine the highest color sequence and zuidi.
    For the color sequence, see Table 1 below (from one position to another, the sample needs to be rotated about 90°), and then calculate the birefringence optical path difference of the tested sample with reference to the following
    .

    Example: A certain part of the specimen is sky blue at the highest color sequence position, and the combined optical path difference between the specimen and the full-wave plate is δ′= 664 nm from Table (1), which is obviously the optical path difference between the specimen and the full-wave plate.
    The result of adding the path difference (the fast axis of the specimen and the fast axis of the full-wave plate are parallel to each other)
    .

    Put δ′ into formula ① to get δ = 664–565 = 99 nanometers
    .

    After the test piece is rotated 90°, the same part will be in the lowest color sequence position.
    The interference color seen by the analyzer is brownish yellow.
    From Table 1, the combined optical path difference between the test piece and the full-wave plate is δ′=430 nm.
    , this value is the result of the subtraction of the optical path difference of the full-wave plate and the optical path difference of the specimen (because the fast axis of the specimen is rotated 90°, the fast axis is parallel to the slow axis of the full-wave plate).
    Bring δ′ into formula ② to get δ = 565 – 430 = 135 nanometers
    .

    The optical path difference of the same part of the test piece is a fixed value, but there is a considerable difference between the two measured δ values.
    This is caused by the subjective error of the human eye in judging color and error factors, and the average value can be taken
    .

    δ=1/2(99+135)=117.
    5nm Quantitative test 1.
    Note: During quantitative measurement, it is necessary to place the 1/4 waveplate (5) into the field of view by rotating the waveplate switching knob (4)
    .

    Rotate the analyzer holder (1) so that the numerical value display window (10) displays the angle as 0 (and the optical path difference also displays as 0)
    .

    At this time, the field of view is observed through the analyzer (2), and the field of view is a dark field
    .

    As shown in Figure 3
    .

     When there is no test piece, switch to 1/4 wave plate to observe 2.
    When the birefringence optical path difference δ of the test piece is not greater than the first-order fringes, there is no obvious interference color in the field of view of the stress tester
    .

    When the analyzer is at the zero position, there are bright areas in the middle of the specimen and near the upper and lower surfaces, which are separated by two dark fringes.
    Rotate the analyzer to make the two dark fringes move toward the middle of the specimen and overlap.
    The numerical value display window (10) can directly read the optical path difference value of the test piece
    .

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