Optical glass stress testing device and digital testing method

Abstract

The invention provides an optical glass stress testing device and a digital testing method, and belongs to the technical field of optical glass detection. The optical glass stress testing device comprises a light source, a diffusion filter, a polarizer, a quantitative wave plate, a polarization analyzer, a circular grating, a CCD (Charge Coupled Device) imaging catcher, a to-be-tested glass strip and an upper computer, wherein the light source, the diffusion filter, the polarizer, the quantitative wave plate, the polarization analyzer, the circular grating and the CCD imaging catcher are sequentially arranged at intervals along the horizontal direction. The circular grating and the polarization analyzer are configured to perform synchronous axial rotation, and the minimum rotation angle of the circular grating is smaller than the minimum rotation angle of the polarization analyzer. A to-be-measured glass strip is arranged between the polarizer and the quantitative wave plate, and the upper computer is used for calculating the stress of the to-be-measured glass strip based on the rotation angle of the circular grating and an image acquired by the CCD imaging capturer. By adopting the optical glass stress testing device and the digital testing method, the data acquisition error in the optical glass stress testing process can be reduced, and the testing accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical glass detection, and in particular to an optical glass stress testing device and a digital testing method. Background Art

[0002] Transparent products such as ordinary glass, organic glass, PET plastic, etc. are increasingly used in the optical field. Due to the particularity of the production process, these products need to undergo corresponding annealing processes when they are formed. The quality of the annealing process directly determines the strength and life of the product. Uneven or incomplete annealing will cause residual internal stress in the product. This residual internal stress is usually extremely uneven, which will reduce the mechanical strength and thermal stability of glass products and affect the safe use of glass products. When the residual internal stress value exceeds the limit, the product may even explode. For optical glass, due to the existence of residual internal stress, the surface of the processed optical parts will slowly deform over time, seriously affecting the imaging quality. The magnitude of residual internal stress has also become one of the important indicators of the optical performance of optical glass. Therefore, in order to ensure the performance of glass products, the residual internal stress of the glass must be controlled within a reasonable range, which requires the detection of the residual internal stress of the glass.

[0003] In the related art, the stress birefringence method is usually used to test the stress of optical glass. By making measurement marks such as scratches on the light-transmitting surface of the sample, polarized light is injected through the light-transmitting surface. When the polarizer behind the sample is in the zero position, the sample is observed and an interference dark band is found. After the interference dark band is moved closer to the measurement mark and overlapped by rotating the polarizer, the optical path difference is read by the polarization stress meter at the rear end of the analyzer to obtain the test stress of the sample.

[0004] When using the traditional test method in the relevant technology, the overlap of the interference dark bands needs to be observed and judged by the test personnel through the naked eye when obtaining the optical path difference data. Since the interference dark bands produced by the optical glass lock are usually images of varying widths, observation with the naked eye is prone to large errors due to subjective factors, which in turn affects the rotation angle of the polarizer and the accuracy of the final optical path difference data acquisition, resulting in poor accuracy of the optical glass stress test structure. Summary of the invention

[0005] The embodiment of the present invention provides an optical glass stress testing device and a digital testing method, which can reduce the error of data acquisition during the optical glass stress testing process and improve the testing accuracy. The technical solution is as follows:

[0006] In a first aspect, an embodiment of the present invention provides an optical glass stress testing device, comprising: a light source, a diffusion filter, a polarizer, a quantitative wave plate, an analyzer, a circular grating, a CCD imaging capture device, a glass strip to be tested, and a host computer.

[0007] The light source, the diffuse filter, the polarizer, the quantitative wave plate, the analyzer, the circular grating and the CCD imaging capturer are arranged in sequence and spaced apart in the horizontal direction; the circular grating and the analyzer are configured to perform synchronous axial rotation; the minimum rotation angle of the circular grating is smaller than the minimum rotation angle of the analyzer; the glass strip to be tested is arranged between the polarizer and the quantitative wave plate; and the host computer is used to calculate the stress of the glass strip to be tested based on the rotation angle of the circular grating and the image acquired by the CCD imaging capturer.

[0008] Optionally, the minimum rotation angle of the circular grating is 0.5°.

[0009] Optionally, the optical glass stress testing device further comprises a driving motor and an angle display, wherein the driving motor is configured to drive the circular grating and the analyzer to rotate axially synchronously, and the angle display is connected to the driving motor for reading the rotation angle of the circular grating.

[0010] Optionally, the peak wavelength range of the diffusion filter is 535 to 545 nm.

[0011] Optionally, the quantitative wave plate is a λ / 4 wave plate.

[0012] Optionally, both the polarizer and the analyzer are linear polarizers.

[0013] In a second aspect, an embodiment of the present invention provides a digital testing method, which is implemented based on the optical glass stress testing device described in the first aspect, and the digital testing method includes:

[0014] The glass strip to be tested is arranged between the polarizer and the quantitative wave plate, and the image of the glass strip to be tested is acquired by using the CCD imaging capture device;

[0015] Based on the light transmission width and light transmission thickness of the glass strip to be tested, a virtual straight mark is generated on the image of the glass strip to be tested by using computer testing software;

[0016] The light source is used to emit light to the light-transmitting surface of the glass strip to be tested to form a test light path, polarized light is formed through the diffusion filter and the polarizer, and the CCD imaging capture device is used to obtain the image information of the light-transmitting dark band on the glass strip to be tested, and the light-transmitting dark band is generated and fed back to the image of the glass strip to be tested;

[0017] The analyzer and the circular grating are rotated synchronously, and synchronous sampling is performed through the CCD imaging capture device until the light-transmitting dark band coincides with the virtual straight bar mark, and the stress data of the glass strip to be tested is calculated by the host computer based on the rotation angle of the circular grating.

[0018] Optionally, on the light-transmitting surface of the glass strip to be tested, the distance between the virtual straight mark and an edge of one side of the light-transmitting surface is less than or equal to 5% of the width of the light-transmitting surface.

[0019] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0020] With the optical glass stress testing device provided by the embodiment of the present invention, the operator only needs to place the glass strip to be tested on the polarizer and the quantitative wave plate, start the light source, and use the host computer to drive and control the synchronous rotation of the analyzer and the circular grating, and use the added CCD imaging capturer to shoot the moving image of the interference dark band generated by stress birefringence on the glass strip to be tested, so as to perform a fully automatic quantitative test of stress data. Compared with the traditional testing method, the testing device uses a circular grating with a smaller minimum rotation angle than the analyzer to obtain the rotation angle, and uses the image obtained by the CCD imaging capturer to digitally generate and process the glass strip to be tested, the virtual straight bar mark, and the light-transmitting dark band stripes and perform rotation simulation in the host computer using the testing software, instead of the traditional method of judging the overlap of the light-transmitting dark band and the physical mark by observing the human eye, which can effectively reduce the error of data acquisition in the optical glass stress test process and improve the test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 is a schematic structural diagram of an optical glass stress testing device provided by an embodiment of the present invention;

[0023] Figure 2 is a control structure block diagram of an optical glass stress testing device provided by an embodiment of the present invention;

[0024] Figure 3 It is a flow chart of a digital testing method provided by an embodiment of the present invention.

[0025] In the figure: 1-light source; 2-diffuse filter; 3-polarizer; 4-quantitative wave plate; 5-analyzer; 6-circular grating; 7-CCD imaging capture device; 8-glass strip to be tested; 9-host computer; 61-drive motor; 62-angle display. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0027] Figure 1 is a schematic structural diagram of an optical glass stress testing device provided by an embodiment of the present invention; Figure 2 : is a control structure block diagram of the optical glass stress testing device provided by an embodiment of the present invention. Figures 1 to 2 As shown, an embodiment of the present invention provides an optical glass stress testing device, including a light source 1, a diffusion filter 2, a polarizer 3, a quantitative wave plate 4, an analyzer 5, a circular grating 6, a CCD imaging capture device 7 and a glass strip to be tested 8.

[0028] Among them, the light source 1, the diffuse filter 2, the polarizer 3, the quantitative wave plate 4, the analyzer 5, the circular grating 6 and the CCD imaging capture device 7 are arranged in sequence and spaced in the horizontal direction. The circular grating 6 and the analyzer 5 are configured to perform synchronous axial rotation, and the minimum rotation angle of the circular grating 6 is smaller than the minimum rotation angle of the analyzer 5. The glass strip 8 to be tested is arranged between the polarizer 3 and the quantitative wave plate 4.

[0029] In the embodiment of the present invention, compared with the stress test method of the traditional optical glass, the present application improves and perfects the test device, and introduces the host computer 9 to perform the test in combination with the corresponding test software. A circular grating 6 that can rotate with the analyzer 5 is added behind the analyzer 5 in the direction of the optical path, and a CCD imaging capturer 7 is used, for example, a camera based on a CCD (Charge-coupled Device) image sensor is used to obtain the test image of the glass strip 8 to be tested. Among them, the circular grating 6 and the analyzer 5 are connected by an additionally arranged drive motor 61, and the drive motor 61 is also connected to the host computer 9 such as a computer to realize synchronous drive, and the angle display 62 is used to obtain the rotation angle of the synchronously rotating circular grating 6. In the process of stress testing, the glass strip 8 to be tested is first set between the polarizer 3 and the quantitative wave plate 4, and the image of the glass strip 8 to be tested is obtained by using the CCD imaging capturer 7. Afterwards, the specifications and dimensions of the glass strip 8 to be tested are measured, and the width of the light-transmitting surface and the overall light-transmitting thickness of the glass strip 8 to be tested are input into the test software of the computer, and a virtual straight mark (a straight thick line parallel to one side edge of the light-transmitting surface after software processing) is generated on the image of the glass strip 8 to be tested by using the computer test software. Afterwards, the light source 1 is started, and the light source 1 is used to emit light to the light-transmitting surface of the glass strip 8 to be tested to form a test light path, and polarized light is formed through the diffuse filter 2 and the polarizer 3, and the light-transmitting dark band image information on the glass strip 8 to be tested is obtained by using the CCD imaging capture device 7, and the light-transmitting dark band generation is fed back to the image of the glass strip 8 to be tested. Afterwards, the host computer 9 controls the driving motor 61 to supply power, synchronously rotates the analyzer 5 and the circular grating 6, and synchronously continuously samples through the CCD image capture device 7. When the light-transmitting dark band on the actual glass strip 8 to be tested moves, the light-transmitting dark band stripe image on the image of the glass strip 8 to be tested in the test software in the host computer 9 will also move accordingly and move closer to the virtual straight bar mark. When the light-transmitting dark band stripe image completely overlaps with the virtual straight bar mark, the driving of the analyzer 5 and the circular grating 6 is stopped, and the rotation angle of the circular grating 6 is recorded. According to formula (1): And the thickness d of the glass strip 8 to be tested, the stress data of the glass strip 8 to be tested is automatically calculated. In formula (1), δ is the optical path difference of the glass strip 8 to be tested; λ is the wavelength of the monochromatic light emitted by the light source 1; θ is the rotation angle of the circular grating 6; N is the interference order, and the size of N is the number of dark bands generated by the glass strip 8 to be tested after being irradiated with polarized light minus one. After obtaining the optical path difference of the glass strip 8 to be tested through formula (1), according to formula (2): Obtain the optical path difference δ per unit thickness of the glass strip 8 to be tested n , where δ maxWhen polarized light is irradiated, if there are multiple light-passing dark bands on the glass strip 8 to be tested, each light-passing dark band is moved closer to the virtual straight mark, and the value of the maximum optical path difference δ obtained by formula (1) is obtained. Finally, the host computer 9 uses the unit thickness optical path difference δ of the glass strip 8 to be tested n The stress data of the glass strip 8 to be tested can be automatically calculated.

[0030] With the optical glass stress testing device provided by the embodiment of the present invention, the operator only needs to place the glass strip 8 to be tested on the polarizer 3 and the quantitative wave plate 4, start the light source 1, and use the host computer 9 to drive and control the polarizer 5 and the circular grating 6 to rotate synchronously, and use the additional CCD imaging capture device 7 to shoot the moving image of the interference dark band generated by stress birefringence on the glass strip 8 to be tested, so as to perform a fully automatic quantitative test of stress data. Compared with the traditional testing method, the testing device selects a circular grating 6 with a minimum rotation angle smaller than the polarizer 5 to obtain the rotation angle, and at the same time uses the image obtained by the CCD imaging capture device 7, and uses the test software in the host computer 9 to digitally generate and process and rotate the glass strip 8 to be tested, the virtual straight bar mark, and the light-transmitting dark band stripes, instead of the traditional method of judging the overlap of the light-transmitting dark band and the physical mark by observing the human eye, which can effectively reduce the error of data acquisition in the optical glass stress test process and improve the test accuracy.

[0031] Optionally, the minimum rotation angle of the circular grating 6 is 0.5°, and the quantitative wave plate 4 is a λ / 4 wave plate. Exemplarily, in an embodiment of the present invention, in the national standard stress birefringence test method, the quantitative wave plate also selects a λ / 4 wave plate with an optical path difference of 135nm±5nm. When obtaining the rotation angle of the polarizer, the prior art uses a traditional dial for comparison, and the dial is engraved according to 540nm / 180°, that is, two 180° are engraved on a circle, and the error is ±3nm, which means there is an error of ±1°. Using a circular grating 6 with a minimum rotation angle of 0.5°, the rotation angle is obtained more accurately, and the stress accuracy finally obtained is higher than that of the national standard method.

[0032] Optionally, the peak wavelength of the diffusion filter 2 is in the range of 535 to 545 nm. Preferably, in the embodiment of the present invention, the peak wavelength of the diffusion filter 2 is 540 nm, the half-width of the band is 6 nm, and no secondary peak appears in the visible light region.

[0033] Optionally, the polarizer 3 and the analyzer 5 are both linear polarizers. Preferably, in the embodiment of the present invention, the polarizer 3 and the analyzer 5 are both polarizers with a polarization degree not less than 0.99.

[0034] refer to Figure 3 The embodiment of the present invention also provides a digital testing method based on Figure 1 to Figure 2The optical glass stress testing device shown is implemented, comprising:

[0035] S1 . The glass strip 8 to be tested is arranged between the polarizer 3 and the quantitative wave plate 4 , and the image of the glass strip 8 to be tested is acquired by using the CCD imaging capture device 7 .

[0036] S2. Based on the light transmission width and light transmission thickness of the glass strip material 8 to be tested, a virtual straight mark is generated on the image of the glass strip material 8 to be tested by using computer testing software.

[0037] S3. Use the light source 1 to emit light to the light-transmitting surface of the glass strip 8 to be tested to form a test light path, form polarized light through the diffuse filter 2 and the polarizer 3, use the CCD imaging capture device 7 to obtain the image information of the light-transmitting dark band on the glass strip 8 to be tested, and feed back the light-transmitting dark band generation to the image of the glass strip 8 to be tested.

[0038] S4, synchronously rotate the polarizer 5 and the circular grating 6, and perform synchronous sampling through the CCD imaging capture device 7 until the dark band of the light passes through coincides with the virtual straight mark, and use the host computer 9 to calculate the stress data of the glass strip material 8 to be tested based on the rotation angle of the circular grating 6.

[0039] By using the optical glass stress testing device provided by the embodiment of the present invention and performing digital testing on the optical glass stress by the above-mentioned testing method, the operator only needs to place the glass strip 8 to be tested on the polarizer 3 and the quantitative wave plate 4, start the light source 1, and use the host computer 9 to drive and control the polarizer 5 and the circular grating 6 to rotate synchronously, and use the additional CCD imaging capture device 7 to shoot the moving image of the interference dark band generated by stress birefringence on the glass strip 8 to be tested, so as to perform full-automatic quantitative testing of stress data. Compared with the traditional testing method, the testing device selects the circular grating 6 with a minimum rotation angle smaller than the polarizer 5 to obtain the rotation angle, and uses the image obtained by the CCD imaging capture device 7, and uses the testing software in the host computer 9 to perform digital generation and processing and rotation simulation on the glass strip 8 to be tested, the virtual straight bar mark, and the light-transmitting dark band stripe, instead of the judgment method of observing the overlap of the light-transmitting dark band and the physical mark by human eyes in the traditional method, which can effectively reduce the error of data acquisition in the optical glass stress testing process and improve the testing accuracy.

[0040] Optionally, on the light-transmitting surface of the glass strip 8 to be tested, the distance between the virtual straight bar mark and the edge of one side of the light-transmitting surface is less than or equal to 5% of the width of the light-transmitting surface. For example, in the embodiment of the present invention, if there is residual stress inside the optical glass, the stress at the edge is usually greater than the stress at the center. Therefore, in the present test method, when the virtual straight bar mark is digitally generated by the test software, it is set at a position close to the edge of one side of the light-transmitting surface. If the calculated edge stress meets the glass strip within the stress range required by the product manufacturing standard, the overall quality can be determined. At the same time, when testing the edge stress, the number of dark bands observed and photographed after polarized light irradiation is usually no more than one, which can further reduce the overall data acquisition and adjustment steps and further improve the test efficiency.

[0041] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0042] The above descriptions are merely optional embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical glass stress testing device, characterized in that: include: A light source (1), a diffusion filter (2), a polarizer (3), a quantitative wave plate (4), an analyzer (5), a circular grating (6), a CCD imaging capture device (7), a glass strip to be tested (8) and a host computer (9), The light source (1), the diffuse filter (2), the polarizer (3), the quantitative wave plate (4), the analyzer (5), the circular grating (6) and the CCD imaging capture device (7) are arranged in sequence and spaced apart in the horizontal direction; the circular grating (6) and the analyzer (5) are configured to perform synchronous axial rotation; the minimum rotation angle of the circular grating (6) is smaller than the minimum rotation angle of the analyzer (5); the glass strip (8) to be tested is arranged between the polarizer (3) and the quantitative wave plate (4); and the host computer (9) is used to calculate the stress of the glass strip (8) to be tested based on the rotation angle of the circular grating (6) and the image acquired by the CCD imaging capture device (7).

2. An optical glass stress testing device according to claim 1, characterized in that: The minimum rotation angle of the circular grating (6) is 0.5°.

3. An optical glass stress testing device according to claim 2, characterized in that: The optical glass stress testing device further comprises a driving motor (61) and an angle display (62), wherein the driving motor (61) is configured to drive the circular grating (6) and the polarizer (5) to rotate axially in sync, and the angle display (62) is connected to the driving motor (61) and is used to read the rotation angle of the circular grating (6).

4. The optical glass stress testing device according to claim 1, characterized in that: The peak wavelength range of the diffusion filter (2) is 535 to 545 nm.

5. The optical glass stress testing device according to claim 1, characterized in that: The quantitative wave plate (4) is a λ / 4 wave plate.

6. The optical glass stress testing device according to claim 1, characterized in that: The polarizer (3) and the analyzer (5) are both linear polarizers.

7. A digital testing method, implemented based on the optical glass stress testing device according to any one of claims 1 to 6, characterized in that: include: The glass strip (8) to be tested is arranged between the polarizer (3) and the quantitative wave plate (4), and an image of the glass strip (8) to be tested is acquired by using the CCD imaging capture device (7); Based on the light transmission width and light transmission thickness of the glass strip material (8) to be tested, a virtual straight bar mark is generated on the image of the glass strip material (8) to be tested using computer testing software; The light source (1) is used to emit light toward the light-transmitting surface of the glass strip (8) to be tested to form a test light path, polarized light is formed through the diffusion filter (2) and the polarizer (3), and the CCD imaging capture device (7) is used to obtain image information of the light-transmitting dark band on the glass strip (8) to be tested, and the light-transmitting dark band is generated and fed back to the image of the glass strip (8) to be tested; The polarizer (5) and the circular grating (6) are rotated synchronously, and synchronous sampling is performed by the CCD imaging capture device (7) until the light-transmitting dark band coincides with the virtual straight bar mark, and the stress data of the glass strip (8) to be tested is calculated by the host computer (9) based on the rotation angle of the circular grating (6).

8. The digital testing method according to claim 7, characterized in that: On the light-transmitting surface of the glass strip (8) to be tested, the distance between the virtual straight mark and the edge of one side of the light-transmitting surface is less than or equal to 5% of the width of the light-transmitting surface.

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