Glass surface stress detection device

Abstract

The present application discloses a glass surface stress detection device for detecting the surface stress of glass within a refractive index range from n1 to n2 (n1 < n2), which includes an illumination unit, a detection prism, an imaging unit, and a reflector. The reflector is arranged between the detection prism and the imaging unit and is used to reflect the light from the detection prism to the imaging unit. Among them, the reflector is arranged in the overlapping area of the irradiation area of the light beam derived from the detection prism when the critical angle of total reflection is arcsin(n1 / n0) and the irradiation area of the light beam derived from the detection prism when the critical angle is arcsin(n2 / n0), where n0 is the refractive index of the detection prism. The arrangement of the reflector enables it to receive the light derived from the detection prism when detecting different glass materials, so that the horizontal position of the reflector does not need to be adjusted. On the one hand, this enables the further simplification of the structure of the detection device, and on the other hand, it also facilitates the operation of the detection device.

Description

Technical Field

[0001] The present disclosure relates to an optical detection device, and in particular, to a glass surface stress detection device. Background Art

[0002] Glass plates are common materials in daily life and industrial production. In order to measure the quality of glass plates and ensure the safety of glass plates, it is often necessary to measure the stress in the glass plates. In order to detect the stress of glass plates, it is stipulated in national standards and other standards that the surface stress of glass is measured by birefringence to characterize the stress level inside the glass. At present, in actual use, the main methods for measuring the surface stress of glass are: differential surface refraction method DSR (Differential Surface Refractometry), surface grazing angle polarization method GASP (Grazing Angle Surface Plarimetry), and the transmission laser method recently introduced in Estonia. Among them, the DSR measurement method is widely used by various testing institutions because it uses fewer optical elements and the price of the testing instrument is relatively low. The GASP measurement method has a higher measurement accuracy for tempered glass with relatively low surface stress, and is suitable for surface stress detection of semi-tempered glass used in buildings.

[0003] However, the existing glass surface stress detection device suitable for the GASP measurement method needs to adjust the horizontal position and pitch angle range of the reflector during the measurement process, and there are many parts for manual adjustment, which is cumbersome to operate and inefficient. Summary of the invention

[0004] In view of the above-mentioned defects or shortcomings in the prior art, the present invention provides a portable glass surface stress detection device with simple structure and easy operation.

[0005] According to an aspect of the present invention, there is provided a glass surface stress detection device for detecting the surface stress of glass within a refractive index range from n1 to n2 (n1 < n2), which includes: an illumination unit for providing polarized illumination light, the illumination unit including a light source; a detection prism having a detection surface for fitting with the surface of the glass to be detected for detection, at least part of the light incident on the detection prism from the illumination unit undergoes total reflection at the fitting portion between the detection surface and the surface of the glass to be detected, and part of the light enters the glass surface for conduction and then is led out from the detection prism; an imaging unit including a lens group, the imaging unit being arranged to receive the light from the detection prism and form a detection image; and a mirror arranged between the detection prism and the imaging unit for reflecting the light from the detection prism to the imaging unit, wherein the mirror is arranged in the overlapping region of the irradiation area of the light beam led out from the detection prism when the critical angle of the total reflection is arcsin(n1 / n0) and the irradiation area of the light beam led out from the detection prism when the critical angle is arcsin(n2 / n0), where n0 is the refractive index of the detection prism.

[0006] Preferably, the mirror is arranged to be adjustable only in the pitch direction.

[0007] Preferably, the glass surface stress detection device further includes an adjustment device for adjusting the pitch angle of the mirror.

[0008] Preferably, the detection prism is configured such that the angle formed between the surface for leading out light from the detection prism and the detection surface is within the range of arcsin(n1 / n0) to arcsin(n2 / n0).

[0009] Preferably, the light source of the illumination unit includes a laser and a collimating and beam-expanding lens, and the collimating and beam-expanding lens expands the diameter of the light beam from the laser.

[0010] Preferably, the imaging unit further includes a quartz wedge and an analyzer, and the light from the mirror enters the lens group successively through the quartz wedge and the analyzer.

[0011] Preferably, the detection prism further includes a reflecting surface for reflecting the light entering the detection prism and guiding it to the detection surface.

[0012] According to the present invention, the arrangement of the mirror enables it to receive the light led out from the detection prism when detecting different glass materials, so that there is no need to adjust the horizontal position of the mirror. On the one hand, this can further simplify the structure of the detection device, and on the other hand, it also facilitates the operation of the detection device. Description of the Drawings

[0013] Other features, objectives, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which like reference numerals represent the same or corresponding components and features.

[0014] Figure 1 Schematic structural diagram of a glass surface stress detection device according to Embodiment 1 of the present invention;

[0015] Figure 2 is Figure 1 Schematic layout diagram of the mirrors of the glass surface stress detection device shown;

[0016] Figure 3 shows an example of a detection prism that can be applied to Figure 1 the glass surface stress detection device shown. Detailed implementation manners

[0017] The following further elaborates on the present application in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are merely for explaining the relevant invention and are not intended to limit the invention. Additionally, it should be noted that for ease of description, only parts related to the invention are shown in the drawings.

[0018] Figure 1 Schematic structural diagram of a glass surface stress detection device according to Embodiment 1 of the present invention.

[0019] The glass surface stress detection device 100 is used to detect the surface stress of glass within the refractive index range from n1 to n2 (n1 < n2), and it includes: an illumination unit 10, a detection prism 20, and an imaging unit 30.

[0020] The illumination unit 10 is used to provide polarized illumination light, and this illumination unit includes a light source 11.

[0021] In Figure 1 the shown example, the light source 11 in the illumination unit 10 includes a laser 12 and a collimating and beam-expanding lens 13. The laser 12 emits laser light with good monochromaticity, good coherence, good directivity, and high brightness. The collimating and beam-expanding lens 13 is used to expand the diameter of the beam from the laser 12. However, in this regard, the present invention is not limited thereto; in the glass surface stress detection device according to the present invention, the light source can also take other suitable forms. For example, the light source can include a monochromatic LED, and the use of a collimating and beam-expanding lens is not limited.

[0022] The detection prism 20 has a detection surface 20a for contacting with the surface of the glass to be detected for detection. At least part of the light incident on the detection prism 20 from the lighting unit 10 is totally reflected at the contact point between the detection surface 20a and the surface of the glass to be detected, and then guided out from the detection prism 20. The detection prism 20 may also include a reflection surface 20b for reflecting the light entering the detection prism 20 and guiding it to the detection surface. Figure 1 As shown, the imaging unit 30 may include a quartz wedge 32, an analyzer 33 and a lens 34 arranged in sequence along the optical path. The imaging unit 30 is arranged to receive light from the detection prism 20 and form a detection image.

[0023] When the glass surface stress detection device 100 is working, the convergent light beam from the lighting unit 10 enters the detection prism 20 and irradiates the detection surface 20a, wherein at least part of the light with the critical angle of total reflection enters the detected glass surface, propagates along the glass surface for a distance, and is coupled and derived by the detection surface 20a. Due to the stress on the glass surface, the light beam produces a birefringence phenomenon, so the light derived from the detection surface 20a contains an optical path difference in one direction. The derived light passes through the quartz wedge 32 and then the analyzer 33 and then is emitted to the lens group 34. The quartz wedge 32 can be used to make the light produce an optical path difference in another different direction, which is superimposed on the optical path difference caused by birefringence, so that the light interference produces inclined interference fringes. The glass surface stress value is proportional to the tangent function of the inclination angle of the interference fringes. By measuring the inclination angle of the interference fringes, the glass surface stress value can be calculated.

[0024] Reference above Figure 1 The structure of the glass surface stress detection device 100 shown is merely exemplary, and the detection device 100 may also include other components not described herein or components having similar functions that are used to replace the components described above.

[0025] The glass surface stress detection device 100 according to an embodiment of the present invention further includes a reflector 31. The reflector 31 is arranged between the detection prism 20 and the imaging unit 30, and is used to reflect the light from the detection prism 20 to the imaging unit 30. According to the present invention, the reflector 31 is arranged in an overlapping area of ​​the irradiation area of ​​the light beam derived from the detection prism 20 when the critical angle of total reflection is arcsin (n1 / n0) and the irradiation area of ​​the light beam derived from the detection prism 20 when the critical angle is arcsin (n2 / n0), where n0 is the refractive index of the detection prism.

[0026] Since the critical angles of total internal reflection corresponding to glasses with different refractive indices are different, during actual detection, the irradiation area of the light beam derived from the detection prism 20 also varies. Therefore, in the glass surface stress detection device of the existing gasp technology, it is necessary to adjust the horizontal position and pitch angle of the mirror to guide the derived light beam into the imaging unit.

[0027] In the glass surface stress device 100 according to an embodiment of the present invention, by arranging the mirror 31 in the overlapping area of the irradiation area of the light beam derived from the detection prism 20 when the critical angle of total internal reflection is arcsin(n1 / n0) and the irradiation area of the light beam derived from the detection prism 20 when the critical angle is arcsin(n2 / n0), the mirror can receive the light derived from the detection prism 20 when detecting different glass materials without adjusting the horizontal position of the mirror. On the one hand, this enables further simplification of the structure of the detection device, and on the other hand, it also facilitates the operation of the detection device.

[0028] In some examples, the mirror 31 is preferably arranged to be adjustable only in the pitch direction. For example, the glass surface stress detection device 100 may only include an adjustment device (not shown) for adjusting the pitch angle of the mirror 31 to adjust the angle of the light entering the imaging unit 30.

[0029] In addition, the glass surface stress detection device 100 may further include an outer cover 40. The outer cover is preferably a light-shielding outer cover. The light-shielding outer cover 40 houses the above-mentioned illumination unit 10, detection prism 20, imaging unit 30, etc., for shielding stray light from the outside. A detection hole (not shown) may be formed on the light-shielding outer cover 40, and the detection surface 20a of the detection prism 20 is exposed from the detection hole.

[0030] Figure 2 For Figure 1 A schematic diagram of the layout of the mirror in the shown glass surface stress detection device 100.

[0031] Assume that n0 is the refractive index of the detection prism 20, and the refractive index range of the glass to be detected is n1 to n2 (n1 < n2). For example, the refractive index of ordinary float glass is 1.52, while the refractive index of Schott float glass is 1.47, then n1 is 1.47 and n2 is 1.52.

[0032] As Figure 2 shown, the total internal reflection critical angles α1 and β1 of the light beams a and b at the joint of the detection surface 20a of the detection prism 20 and the surface of the glass to be detected are respectively:

[0033] α1 = arcsin(n1 / n0)

[0034] β1 = arcsin(n2 / n0).

[0035] The light beams a and b are refracted when they are guided out from the detection prism 20. Figure 2 In the example shown, the surface of the detection prism 20 for exporting the light beam is perpendicular to the detection surface 20a. In this case, the exit angles of the light beams a and b after refraction are α2 and β2, respectively, and α2 and β2 satisfy:

[0036] sin(α2)=sin(90-α1)*n0

[0037] sin(β2)=sin(90-β1)*n0.

[0038] The irradiation areas of light beams a and b intersect to form four areas A, B, C, and D. Light beam a can be observed in area A, but light beam b cannot be observed; light beam a and light beam b can be observed in area B; light beam b can be observed in area C, but light beam a cannot be observed; and light beam a and light beam b cannot be observed in area D. Area B is the overlapping area of ​​the irradiation area of ​​the light beam derived from the detection prism 20 when the critical angle of total reflection is arcsin (n1 / n0) and the irradiation area of ​​the light beam derived from the detection prism 20 when the critical angle is arcsin (n2 / n0).

[0039] The detection device in the prior art generally places the reflector in area A or area C and moves it back and forth to adjust the horizontal position of the reflector. In the glass surface stress detection device 100 according to the embodiment of the present invention, the reflector 31 is placed in area B. In this way, light a and light b can be observed without moving the reflector 31. When using the glass surface stress detection device 100 according to the embodiment of the present invention to detect the surface stress of glass with different refractive indices, there is no need to adjust the horizontal position of the reflector 31. In this way, the detection device 100 can be constructed so that the reflector 31 is adjustable only in the pitch direction, eliminating the horizontal position adjustment mechanism, making the detection device structure simpler and more compact, and also convenient for operation.

[0040] from Figure 2 As can be seen from the diagram of FIG. 2 , the light beams a and b are refracted on the surface 20b when being guided out from the detection prism 20, and the refraction causes the two light beams to deviate further from each other. In order to allow the light beams a and b to have a larger overlapping area B after being emitted from the detection prism 20, the present invention further proposes the following Figure 3 The shown can be applied to Figure 1 The detection prism of the glass surface stress detection device shown.

[0041] like Figure 3As shown, the surface 20b of the detection prism 20 for guiding light out of the detection prism forms an angle θ with the detection surface 20a, and the angle θ is in the range of arcsin (n1 / n0) to arcsin (n2 / n0). By setting the angle θ in the above range, the surface 20b can be made substantially perpendicular to the light beams a and b, so that the direction deflection caused by the refraction of the light beams a and b at the surface 20b is small, so that the overlapping area B of the light beams a and b after exiting is large. This is conducive to arranging the reflector 31 in the overlapping area B.

[0042] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A glass surface stress detection device using the GASP measurement method, used to detect the surface stress of glass ranging from a refractive index of n1 to a refractive index of n2, where n 1< n2, the glass surface stress detection device comprises: An illumination unit for providing polarized illumination light, the illumination unit comprising a light source; A detection prism having a detection surface for bonding with the surface of the glass to be detected for detection, at least part of the light incident on the detection prism from the lighting unit is totally reflected at the bonding point between the detection surface and the surface of the glass to be detected, and part of the light enters the glass surface for conduction to propagate a distance along the glass surface and then is guided out from the detection prism; an imaging unit, comprising a lens group, arranged to receive light from the detection prism and form a detection image; and a reflector, arranged between the detection prism and the imaging unit, for reflecting light from the detection prism to the imaging unit, It is characterized in that the imaging unit further includes a quartz wedge and an analyzer, and the light from the reflector enters the lens group via the quartz wedge and the analyzer in sequence; and The reflector is arranged in an overlapping area where an illumination area of ​​the light beam derived from the detection prism when the critical angle of total reflection is arcsin(n1 / n0) and an illumination area of ​​the light beam derived from the detection prism when the critical angle is arcsin(n2 / n0), where n0 is the refractive index of the detection prism.

2. The glass surface stress detection device according to claim 1, wherein: The mirrors are arranged to be adjustable only in the elevation direction.

3. The glass surface stress detection device according to claim 1, wherein: It also includes an adjusting device for adjusting the pitch angle of the reflector.

4. The glass surface stress detection device according to claim 1 or 2, wherein: The detection prism is configured such that an angle between a surface for guiding light out of the detection prism and the detection surface is in the range of arcsin(n1 / n0) to arcsin(n2 / n0).

5. The glass surface stress detection device according to claim 1 or 2, wherein: The light source of the lighting unit includes a laser and a collimating beam expander, and the collimating beam expander expands the diameter of the light beam from the laser.

6. The glass surface stress detection device according to claim 1 or 2, wherein: The detection prism also includes a reflection surface that reflects light entering the detection prism and directs it to the detection surface.

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