Method and apparatus for measuring the characteristics of glass substrates

Abstract

The apparatus may include an illumination source disposed in a first region and at least one wavefront sensor. A reflector may be disposed in a second region. A measurement plane may be disposed between the first region and the second region. The reflector may be configured to reflect the light. The at least one wavefront sensor may be configured to detect the light. A method for measuring a characteristic of a glass-based substrate may include emitting light from the illumination source. The method may include propagating the light through a thickness of the glass-based substrate. The method may include propagating the light through a target location on a first major surface of the glass-based substrate. The method may include detecting the light using the at least one wavefront sensor and generating a signal based on the detected light.

Description

Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 63 / 040,247, filed Jun. 17, 2020, the entire contents of which are incorporated herein by reference.

Technical Field

[0002] The present disclosure generally relates to methods and apparatuses for measuring characteristics of glass-based substrates, particularly methods and apparatuses for measuring characteristics of glass-based substrates using an illumination light source.

Background Art

[0003] Display devices include liquid crystal displays (LCDs), electrophoretic displays (EPDs), organic light emitting diode displays (OLEDs), plasma display panels (PDPs), and the like. A display device can be part of a portable electronic device, such as a consumer appliance, smartphone, tablet, wearable device, or laptop.

[0004] Display devices often include one or more glass-based substrates. It is important to identify, characterize, and measure the characteristics in glass-based substrates so that the characteristics can be mitigated before using the glass-based substrates in various applications (e.g., display devices).

[0005] For example, it is known to inspect glass-based substrates using a camera (e.g., a digital camera, a CCD camera) with various techniques, such as bright field illumination, oblique illumination, or knife edge illumination. These techniques can identify the location of features (e.g., inclusions, scratches, bulges, surface breaks) and / or qualitatively characterize the features. However, higher resolutions required to quantitatively characterize features may require careful calibration, long irradiations, multiple irradiations, and / or irradiations at several orientations, if possible using a particular technique.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, there may be a need to develop methods and apparatus that can be used to measure the characteristics of glass substrates. Accurate and quantitative measurement of characteristics may be required. Furthermore, it may be necessary to measure characteristics using methods that do not require frequent calibration (e.g., methods that are not affected by vibration and / or do not require recalibration between measurements). In addition, it may be necessary to measure characteristics rapidly (e.g., in less than 1 second) so that the measurement can be incorporated into or integrated with glass manufacturing equipment. [Means for solving the problem]

[0007] Apparatus and methods for measuring the features of glass substrates are specified herein. The apparatus of this disclosure enables rapid measurement of features during the manufacturing process, increasing manufacturing efficiency and reducing processing time. The apparatus of this disclosure can quantitatively characterize a wide range of feature sizes, reducing the need for multiple inspections. The apparatus of this disclosure minimizes the need for recalibration and / or realignment, reducing downtime.

[0008] The inclusion of at least one wavefront sensor can enable quantitative and accurate measurement of features unaffected by vibration. For example, using a wavefront sensor can reduce the need for recalibration of the device. For example, using a wavefront sensor can enable measurements while the glass substrate is moving and / or after it has been moved. Similarly, the inclusion of a wavefront sensor can enable rapid measurement of features (e.g., less than approximately 100 milliseconds). Furthermore, the wavefront sensor can be integrated with additional (e.g., existing) inspection equipment (e.g., a camera).

[0009] Providing at least one wavefront sensor can enable measurements at various distances from the measurement plane (e.g., the first primary surface of a glass substrate). Adjusting the distance from the measurement plane can enable the differentiation of different types of features (e.g., surface contours, blistering, gaseous inclusions, metallic inclusions). Adjusting the distance from the measurement plane can also be used to adjust the size of features that can be detected accurately and quantitatively. Providing two or more wavefront sensors with different magnifications can enable simultaneous measurement of a wide range of feature sizes. For example, using two or more wavefront sensors with different magnifications can reduce the need for subsequent inspection (e.g., re-inspection) of features.

[0010] Placing one or more wavefront sensors and illumination sources in a first region opposite to a second region containing a reflector, and having a measurement plane (e.g., a glass substrate) between the first and second regions, can reduce (e.g., mitigate) the alignment challenges between the illumination source and the wavefront sensors. For example, providing a common support for both the illumination source and the wavefront sensors can maintain alignment even when susceptible to vibration or intentionally moved.

[0011] While several embodiments of this disclosure are described below, it is understood that any feature of these various embodiments may be used individually or in combination with each other.

[0012] In some embodiments, the apparatus may comprise an illumination source and at least one wavefront sensor located in a first region. The apparatus may comprise a reflector located in a second region. The apparatus may comprise a measuring plane located between the first and second regions. The illumination source may be configured to emit light projected onto the measuring plane. The reflector may be configured to reflect light from the illumination source. The at least one wavefront sensor may be configured to detect light reflected by the reflector.

[0013] In another embodiment, the path distance between the illumination light source and the measuring plane may be adjustable.

[0014] In another embodiment, the detection distance between the at least one wavefront sensor and the measuring plane may be adjustable.

[0015] In another embodiment, the illumination source may be configured to emit light consisting of coherent light.

[0016] In another embodiment, the illumination source may be configured to emit light consisting of pulses.

[0017] In another embodiment, the illumination source may consist of a laser.

[0018] In another embodiment, the at least one wavefront sensor may consist of a Shack-Hartmann wavefront sensor.

[0019] In another embodiment, the at least one wavefront sensor may consist of a lateral shearing interferometer.

[0020] In yet another embodiment, the transverse shearing interferometer may be a four-wave transverse shearing interferometer.

[0021] In another embodiment, the at least one wavefront sensor may consist of a pyramidal wavefront sensor.

[0022] In another embodiment, the apparatus may further include a beam splitter configured to split the light into a plurality of beams. The at least one wavefront sensor may include a first wavefront sensor configured to detect a first beam from the plurality of beams and a second wavefront sensor configured to detect a second beam from the plurality of beams.

[0023] In yet another embodiment, the apparatus may further include a second optical element configured to change the magnification of the second beam relative to the magnification of the first beam.

[0024] In yet another embodiment, the apparatus may further include an optical element configured to change the magnification of the first beam.

[0025] In yet another embodiment, the apparatus may further include an optical camera configured to detect the first beam among the plurality of beams.

[0026] In some embodiments, a method of measuring characteristics of a glass-based substrate may include projecting light onto a measurement plane of the glass-based substrate. The measurement plane may extend perpendicular to the thickness of the glass-based substrate. The thickness may be defined between a first major surface and a second major surface of the glass-based substrate. The method may include reflecting the light toward the glass-based substrate. The method may include propagating the reflected light through the thickness of the glass-based substrate toward the first major surface of the glass-based substrate through a target position on the first major surface of the glass-based substrate. The method may include detecting the light propagated through the target position using at least one wavefront sensor. The method may include generating a first signal with the at least one wavefront sensor based on the detected light.

[0027] In another embodiment, the step of projecting the light onto the measurement plane may consist of projecting the light onto the first major surface of the glass-based substrate.

[0028] In another embodiment, the method may further include moving the glass-based substrate in a direction perpendicular to the thickness of the glass-based substrate before propagating the light through the thickness. The method may further include moving the glass-based substrate in a direction perpendicular to the thickness of the glass-based substrate after detecting the light propagated through the target position using the at least one wavefront sensor.

[0029] In yet another embodiment, after moving the glass-based substrate before propagating the light through the thickness and before generating the first signal with the at least one wavefront sensor, the at least one wavefront sensor may not generate a signal.

[0030] In yet another embodiment, the measurement time is defined between the end of the movement of the glass substrate before the light propagates through the thickness and the start of the movement of the glass substrate after the detection of the light propagating through the target position using the at least one wavefront sensor, and may be about 100 milliseconds or less.

[0031] In another embodiment, as the light propagates through the thickness of the glass substrate, the glass substrate may move in a direction perpendicular to the thickness of the glass substrate.

[0032] In some embodiments, a method for measuring the characteristics of a glass substrate may include the step of propagating light through the thickness of the glass substrate toward a first main surface of the glass substrate, through a target position on the first main surface of the glass substrate. The thickness may be defined between the first main surface and a second main surface. The method may include the step of detecting the light propagated through the target position using at least one wavefront sensor. The method may include the step of generating a first signal with the at least one wavefront sensor based on the detected light. While the light is propagating through the thickness of the glass substrate, the glass substrate may move in a direction perpendicular to the thickness of the glass substrate.

[0033] In some embodiments, a method for measuring the characteristics of a glass substrate may include the step of propagating light through the thickness of the glass substrate toward a first main surface of the glass substrate, through a target position on the first main surface of the glass substrate. The thickness may be defined between the first main surface and a second main surface. The method may include the step of detecting the light propagated through the target position using at least one wavefront sensor. The method may include the step of generating a first signal with the at least one wavefront sensor based on the detected light. The method may include the step of moving the glass substrate in a direction perpendicular to the thickness before the light propagates through the thickness of the glass substrate. The method may include the step of moving the glass substrate in a direction perpendicular to the thickness of the glass substrate after detecting the light propagated through the target position using the at least one wavefront sensor. The measurement time is defined between the end of the movement of the glass substrate before the light propagates through the thickness and the start of the movement of the glass substrate after the detection of the light propagated through the target position using the at least one wavefront sensor, and may be about 100 milliseconds or less.

[0034] In another embodiment, the method may further include the step of projecting light onto a measuring plane of the glass substrate. The measuring plane may extend perpendicular to the thickness of the glass substrate. The thickness may be defined between a first principal surface and a second principal surface of the glass substrate. The method may further include the step of reflecting the light toward the glass substrate before the light propagates through the thickness.

[0035] In another embodiment, the method may further include the step of determining the height and / or width of the features of the glass substrate based on the generated first signal.

[0036] In yet another embodiment, the step of determining the height and / or width of the features of the glass substrate may further be based on the refractive index of the glass substrate.

[0037] In another embodiment, the feature may be the surface contour of the glass substrate at the target position.

[0038] In another embodiment, the feature may be an inclusion beneath the first main surface at the target location of the glass substrate.

[0039] In yet another embodiment, the impurity may consist of a gas.

[0040] In yet another embodiment, the impurities may consist of metal.

[0041] In another embodiment, the at least one wavefront sensor may consist of a Shack-Hartmann wavefront sensor.

[0042] In another embodiment, the at least one wavefront sensor may consist of a lateral shearing interferometer.

[0043] In yet another embodiment, the transverse shearing interferometer may be a four-wave transverse shearing interferometer.

[0044] In another embodiment, the at least one wavefront sensor may consist of a pyramidal wavefront sensor.

[0045] In another embodiment, the method may further include the step of splitting the light propagated through the target position into a plurality of beams, including a first beam and a second beam. The method may further include the step of changing the magnification of the first beam. The step of detecting the propagated first pulse using at least one wavefront sensor may include the step of detecting the first beam with the first wavefront sensor of the at least one wavefront sensor. The step of detecting the propagated first pulse using at least one wavefront sensor may further include the step of detecting the second beam with the second wavefront sensor of the at least one wavefront sensor.

[0046] In another embodiment, the method may further include the step of splitting the light propagated through the target position into a plurality of beams, including a first beam and a second beam. The method may further include the step of changing the magnification of the first beam. The step of detecting the propagated light using the at least one wavefront sensor may include the step of detecting the first beam with a first wavefront sensor of the at least one wavefront sensor, and the step of detecting the second beam with a second wavefront sensor of the at least one wavefront sensor.

[0047] In yet another embodiment, the step of changing the magnification of the first beam may vary the magnification in the range of about 2× to about 50×.

[0048] In yet another embodiment, the method may further include the step of varying the magnification of the second beam relative to the magnification of the first beam.

[0049] In yet another embodiment, the magnification of the first beam may be about 150% to about 1000% of the magnification of the second beam.

[0050] In yet another embodiment, the method may further include the step of detecting the first beam with an optical camera.

[0051] In another embodiment, the light may consist of a first pulse. The method may further include the step of adjusting the detection distance between the first main surface and the at least one wavefront sensor. The method may further include the step of projecting a second pulse onto the measuring plane. The method may further include the step of reflecting the second pulse toward the glass substrate and propagating it through the thickness of the glass substrate. The method may further include the step of propagating the reflected second pulse toward the first main surface of the glass substrate through the target position on the first main surface of the glass substrate. The method may further include the step of detecting the second pulse propagated through the target position using the at least one wavefront sensor. The method may further include the step of generating a second signal with the at least one wavefront sensor based on the detected second pulse.

[0052] In yet another embodiment, the method may further include the step of measuring the feature using the first signal and the second signal. [Brief explanation of the drawing]

[0053] The above and other features and advantages of the embodiments of this disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings. [Figure 1] A typical embodiment of the measuring device according to the present disclosure is shown. [Figure 2] A typical embodiment of the measuring device according to the present disclosure is shown. [Figure 3] A typical embodiment of the measuring device according to the present disclosure is shown. [Figure 4] This is an enlarged view of item 4 in Figure 1. [Figure 5] This is a schematic diagram of a detector comprising at least one wavefront sensor according to an embodiment of the present disclosure. [Figure 6] This is a schematic diagram of a detector comprising at least one wavefront sensor according to an embodiment of the present disclosure. [Figure 7] This is a schematic diagram of a wavefront sensor. [Figure 8] This is a schematic diagram of a wavefront sensor. [Figure 9] This is a cross-sectional view along line 9-9 in Figure 7. [Figure 10] This is a cross-sectional view along line 10-10 in Figure 8. [Figure 11] This is a flowchart illustrating the method of the embodiment of this disclosure. [Figure 12] This is a graph showing the relationship between the measured feature height and the actual feature height according to the embodiments of this disclosure.

[0054] Throughout this disclosure, the drawings are used to emphasize certain aspects. That is, unless otherwise specified, the relative sizes of separate areas, parts, and substrates shown in the drawings should not be considered to be proportional to their actual relative sizes. [Modes for carrying out the invention]

[0055] The embodiments are described more fully below with reference to the accompanying drawings showing representative embodiments. Wherever possible, the same reference numerals are used throughout the drawings to refer to the same or similar parts. However, the claims may include many different aspects of various embodiments and should not be construed as being limited to the embodiments expressed herein.

[0056] Figures 1-3 illustrate apparatus 101 and 301 according to embodiments of the present disclosure. Unless otherwise specified, descriptions of features in some embodiments may apply equally to corresponding features in any embodiment of the present disclosure. For example, identical reference numerals throughout the present disclosure may indicate that in some embodiments the identified features are the same as those of others, and that a description of an identified feature in one embodiment may apply equally to an identified feature in any other embodiment of the present disclosure, unless otherwise specified.

[0057] As shown in Figures 1-3, the devices 101 and 301 may include an illumination light source 121. In some embodiments, the illumination light source 121 may include a laser, a light-emitting diode (LED), and / or an organic light-emitting diode. In other embodiments, the laser may consist of a gas laser, an excimer laser, a dye laser, or a solid-state laser. Embodiments of gas lasers include helium, neon, argon, krypton, xenon, helium-neon (HeNe), xenon-neon (XeNe), carbon dioxide (CO2), carbon monoxide (CO), copper (Cu) vapor, gold (Au) vapor, cadmium (Cd) vapor, ammonia, hydrogen fluoride (HF), and deuterium fluoride (DF). Embodiments of excimer lasers include chlorine, fluorine, iodine, or nitrous oxide (N2O) in an inert environment consisting of argon (Ar), krypton (Kr), xenon (Xe), or a combination thereof. Embodiments of dye lasers include lasers that use organic dyes such as rhodamine, fluorescein, coumarin, stilbene, umbelliferone, tetracene, or malachite green dissolved in a liquid solvent. Embodiments of solid-state lasers include crystalline lasers, fiber lasers, and laser diodes. Crystalline lasers comprise a matrix crystal doped with lanthanides or transition metals. Embodiments of matrix crystals include yttrium aluminum garnet (YAG), yttrium lithium fluoride (YLF), yttrium orthoaluminate (YAL), yttrium scandium gallium garnet (YSSG), lithium aluminum hexafluoride (LiSAF), lithium calcium aluminum hexafluoride (LiCAF), zinc selenium (ZnSe), zinc sulfide (ZnS), ruby, magnesium olivine, and sapphire. Embodiments of the doping agent include neodymium (Nd), titanium (Ti), chromium (Cr), cobalt (Co), iron (Fe), erbium (Er), holmium (Ho), thulium (Tm), ytterbium (Yb), dysprosium (Dy), cerium (Ce), gadolinium (Gd), samarium (Sm), and terbium (Tb).Embodiments of solid crystals include ruby, alexandrite, chromium fluoride, magnesium olivine, lithium fluoride (LiF), sodium chloride (NaCl), potassium chloride (KCl), and rubidium chloride (RbCl). Laser diodes may consist of heterojunction diodes or PIN diodes having three or more materials as p-type, intrinsic, and n-type semiconductor layers. Embodiments of laser diodes include AlGaInP, AlGaAs, InGaN, InGaAs, InGaAsP, InGaAsN, InGaAsNSb, GaInP, GaAlAs, GaInAsSb, and lead (Pb) salts. Some laser diodes may be representative embodiments due to their size, adjustable output power, and ability to operate at room temperature (i.e., about 20°C to about 25°C).

[0058] In some embodiments, the illumination light source 121 may be configured to emit light, as shown in Figures 1-3. In another embodiment, the light may have optical wavelengths in the visible region, for example, in the range of about 300 nanometers (nm) to about 1000 nm, about 350 nm to about 900 nm, about 400 nm to about 800 nm, about 500 nm to about 700 nm, or any range or partial range between these. In yet another embodiment, the first wavelength may be about 365 nm, about 415 nm, or about 590 nm. In yet another embodiment, the light may have optical wavelengths in the infrared region, for example, in the range of about 1 micrometer (μm) to about 20 μm, about 5 μm to about 20 μm, about 5 μm to about 15 μm, about 8 μm to about 15 μm, about 8 μm to about 12 μm, or any range or partial range between these.

[0059] In some embodiments, the illumination source may be configured to emit coherent light. As used in this document, coherent light means that the photons making up the light maintain a generally constant phase difference over a coherent length of 1 meter or more. In another embodiment, the coherent light is spatially coherent, meaning that the light can maintain a generally constant interference pattern over time. In yet another embodiment, the coherent light is temporally coherent, meaning that the light can maintain a generally constant interference pattern at different distances from the illumination source. Typical embodiments of a coherent light source may include a laser, a light-emitting diode (LED), or an organic LED (OLED). In some embodiments, the illumination source may be configured to emit non-coherent light. Typical embodiments of a non-coherent light source may include an incandescent light bulb or LED light emitted through a pinhole aperture.

[0060] In some embodiments, the illumination source may be configured to emit polarized light. As used in this book, polarized light means that the photons making up the light have substantially the same polarization (e.g., linear, circular, elliptical, vertical, horizontal). In some embodiments, though not shown, the illumination source may include an optical compensator (e.g., half-wave plates and / or quarter-wave plates) that can control the polarization of the emitted light. In yet another embodiment, though not shown, one of the half-wave plates or quarter-wave plates that can change the polarization of the passing light beam may be rotatable relative to the other, thereby changing the polarization of the passing light beam. In yet another embodiment, though not shown, the optical compensator may consist of an electronically controlled polarization modulator, such as a liquid crystal based modulator or a ferroelectric liquid crystal based modulator. In some embodiments, the illumination source may be configured to emit unpolarized light (e.g., isotropic, Lambertian (perfectly diffuse)).

[0061] In some embodiments, the illumination source may be configured to emit light continuously. For example, the illumination source may consist of a laser operating in continuous wave (CW) mode. In some embodiments, the illumination source may be configured to emit one or more light pulses. In another embodiment, one of these one or more light pulses may have a pulse duration of about 0.5 nanoseconds (ns) to about 1 millisecond (ms), about 0.5 ns to about 1 microsecond (μs), about 0.5 ns to about 100 ns, about 0.5 ns to about 50 ns, about 0.5 ns to about 20 ns, about 2 ns to about 100 ns, about 2 ns to about 50 ns, about 2 ns to about 20 ns, or any range or partial range between these. In another embodiment, the illumination source may emit multiple pulses as one or more pulse bursts. In yet another embodiment, the pulses of a pulse burst may be spaced apart for times within the ranges of approximately 0.5 ns to approximately 100 ns, approximately 0.5 ns to approximately 50 ns, approximately 0.5 ns to approximately 20 ns, approximately 2 ns to approximately 100 ns, approximately 2 ns to approximately 50 ns, approximately 2 ns to approximately 20 ns, approximately 5 ns to approximately 100 ns, approximately 5 ns to approximately 50 ns, approximately 5 ns to approximately 20 ns, or any range or sub-range between these. Each burst, which is a burst of one or more pulses, may be generated at a frequency within the ranges of approximately 10 kilohertz (kHz) to approximately 1 megahertz (MHz), approximately 10 kHz to approximately 500 kHz, approximately 50 kHz to approximately 1 MHz, approximately 50 kHz to approximately 500 kHz, approximately 100 kHz to approximately 500 kHz, or approximately 100 kHz to approximately 200 kHz, or any range or sub-range between these. In some embodiments, the number of pulses in a pulse burst may be about 20 or less, or about 10 or less, for example, within the ranges of 1 to 10, 1 to 5, 1 to 3, 3 to 10, 3 to 5, or any range or partial range between these. In some embodiments, the number of pulses in a pulse burst may be within the ranges of about 100 to about 1500, about 100 to about 1000, about 100 to about 800, about 300 to about 1500, about 300 to about 1000, about 300 to about 800, about 600 to about 1500, about 600 to about 1000, about 600 to about 800, or any range or partial range between these.

[0062] In some embodiments, as shown in Figures 1-3, the illumination source 121 may be configured to emit light along a first optical path 125. In other embodiments, although not shown, the device (e.g., the illumination source) may include a focusing lens. The focusing lens may be positioned in the middle of the first optical path 125. After passing through the focusing lens, the light may be focused along the first optical path 125. The focusing lens may include a convex lens and / or an adjustable focal length lens. In other embodiments, the focusing lens may be configured to make the light rays parallel along the first optical path 125. In some embodiments, although not shown, a bandpass filter, additional focusing lenses, light diffusers, beam splitters, and / or attenuators may be positioned along the first optical path 125. In other embodiments, one or more of these additional elements may be controlled by a controller 119 via a first communication path 123.

[0063] As shown in Figures 1-3, the devices 101 and 301 may be equipped with a detector 131. As shown in Figures 5 and 6, the detector 131 may be equipped with at least one wavefront sensor. For example, as shown in Figures 5 and 6, the detector may be equipped with a first wavefront sensor 501 and a second wavefront sensor 503. It should be understood that the detector may be equipped with one wavefront sensor, and in other embodiments, three or more wavefront sensors may be provided. Although we do not wish to be constrained by theory, a wavefront sensor may detect light and generate a signal corresponding to the inclination of the wavefront of that light. Although we do not wish to be constrained by theory, the inclination of the wavefront of light may correspond to the path difference between the optical path lengths of different parts of light passing through the sample. As used in this document, the optical path length of light is the physical distance the light travels from the illumination source to the detector multiplied by the refractive index along that distance. It should be understood that the description of the first wavefront sensor 501 may be equally applicable to the second wavefront sensor 503 unless otherwise specified.

[0064] In some embodiments, the first wavefront sensor 501 may consist of a Shack-Hartmann wavefront sensor. As schematically shown in Figures 7 and 8, the Shack-Hartmann wavefront sensor may include a lens array 701. As shown, the lens array 701 may consist of at least one row of lenses. In another embodiment, the lens array 701 may be a two-dimensional array. In yet another embodiment, the first lens of the lens array 701 may have a focal length approximately equal to the focal length of the second lens of the lens array 701. In yet another embodiment, each lens of the lens array 701 may have approximately the same focal length. In yet another embodiment, each lens of the lens array 701 may be approximately identical.

[0065] In some embodiments, the Shack-Hartmann wavefront sensor may include an image detector 703. In another embodiment, as schematically shown in Figures 7 and 8, the image detector 703 may consist of a plurality of photon sensors (e.g., a charge-coupled device (CCD) array, a complementary metal-oxide-semiconductor (CMOS) array, or an optical four-cell array). In yet another embodiment, the plurality of photon sensors may be arranged in at least one row. In yet another embodiment, the plurality of photon sensors may be a two-dimensional array. In yet another embodiment, the number of plurality of photon sensors making up the image detector 703 may be greater than or equal to the number of lenses in the lens array 701.

[0066] As schematically shown in Figures 7 and 8, the Shack-Hartmann wavefront sensor is configured to detect light and / or a beam and to focus that light and / or beam onto a plurality of spots 707, 807 on the imaging plane 705 of the image detector 703 using a lens array 701. Although we do not wish to be constrained by theory, the positions of the spots on the imaging plane focused by the lenses of the lens array may correspond to the inclination of the wavefront of the detected light and / or beam. For example, referring to Figures 7 and 9, a uniform wavefront 711 incident on the wavefront sensor may be focused by the lens array 701 onto a plurality of spots 707 on the imaging plane 705 of the image detector 703. Also, as shown in Figure 9, the spots 903a to 903e, consisting of a plurality of spots 707, may roughly correspond to the neutral positions 901a to 901e on the imaging plane 705. As shown in the figure, the alignment of spots 903a to 903e with the neutral positions 901a to 901e may indicate that the inclination of the incident wavefront of the light and / or beam is nearly zero. For example, referring to Figures 8 and 10, the aberrant wavefront 811 incident on the wavefront sensor can be focused by the lens array 701 onto multiple spots 807 on the imaging plane 705 of the image detector 703. Also, as shown in Figure 10, spots 1003a to 1003e, consisting of multiple spots 807, can deviate to various degrees from the corresponding neutral positions 901a to 901e on the imaging plane 705. Some spots, such as spot 1003b, may be nearly aligned with the corresponding neutral position 901b, indicating that the detected portion of the aberrant wavefront 811 is nearly zero. Other spots, such as spot 1003a, may be shifted by a first distance of 1005 from their corresponding neutral position 901a in the first direction 1001, which may correspond to the inclination of a portion of the aberrated wavefront 811. Spot 1003c may be shifted by a second distance of 1007 from its corresponding neutral position 901c in the opposite direction to the first direction 1001. Also, the first distance 1005 may be approximately equal to the second distance 1007. Other spots, such as spots 1003d and 1003e, may be shifted by distances of 1009 and 1011 from their corresponding neutral positions 901d and 901e, which may be less than the first distance 1005 and / or the second distance 1007.The aberrant wavefront 811 can be estimated (e.g., reproduced) by using the measured distances 1005, 1007, 1009, and 1011 and directions of multiple spots 807 (e.g., spots 1003a to 1003e) from the corresponding neutral positions 901a to 901e as the slope of the aberrant wavefront 811.

[0067] In some embodiments, the first wavefront sensor 501 may consist of a transverse shearing interferometer. In another embodiment, the transverse shearing interferometer may include a diffraction grating configured to generate an interference pattern on the imaging plane of an image detector from the incident light and / or beam. In yet another embodiment, the first wavefront sensor 501 may consist of a four-wave transverse shearing interferometer. In yet another embodiment, the four-wave transverse shearing interferometer may include a beam splitter configured to split the incident light and / or beam into four beams. Each of the four beams may be incident on a diffraction grating configured to generate an interference pattern on the imaging plane of an image detector. In yet another embodiment, each diffraction grating of the four-wave transverse shearing interferometer may have a different pattern and / or different shearing rates. Providing a four-wave transverse shearing interferometer may generate high-resolution data (e.g., signals) that can be used to accurately reproduce the wavefront of the incident light and / or beam.

[0068] In some embodiments, the first wavefront sensor 501 may consist of a pyramidal wavefront sensor. In another embodiment, the pyramidal wavefront sensor may include a pyramidal prism configured to split incident light and / or a beam into a plurality of beams (e.g., four beams) that can be incident on the imaging plane of an image detector. In yet another embodiment, the plurality of beams from the pyramidal prism can be compared to detect information about the inclination of the wavefronts of the incident light and / or the beams.

[0069] As shown in Figures 1-3 and 5, 6, the detector 131 may be configured to detect light traveling along the second optical path 135. In some embodiments, as shown in Figures 5, 6, a beam splitter 505 may be positioned in the middle of the second optical path 135 and configured to split the light incident on the beam splitter 505 into multiple beams. In another embodiment, as shown, the light may be split by the beam splitter 505 into multiple beams, including a first beam 507 and a second beam 509. In yet another embodiment, as shown, the first wavefront sensor 501 may be configured to detect the first beam 507 among the multiple beams. In yet another embodiment, as shown, the second wavefront sensor 503 may be configured to detect the second beam 509 among the multiple beams. In yet another embodiment, as shown, the mirror 511 may be configured to redirect the second beam 509 from the beam splitter 505 towards the second wavefront sensor 503.

[0070] In some embodiments, as shown in Figure 6, the optical camera 601 may be configured to detect the first beam 507 from among multiple beams. In another embodiment, the optical camera 601 may consist of a digital camera, a CCD, and / or an array of photodetectors. In another embodiment, as shown, an additional beam splitter 605 may be configured to split the first beam 507 into multiple split beams and / or direct the first split beam of the multiple split beams toward the optical camera 601 and the second split beam of the multiple split beams toward the first wavefront sensor 501, so that both the optical camera 601 and the first wavefront sensor 501 can detect the first beam 507 generated by the beam splitter 505. Providing a wavefront sensor and an optical camera may enable inspection of glass substrates using multiple techniques with the same detector. As shown in Figure 6, providing a wavefront sensor and an optical camera may enable the integration of the wavefront sensor into the detector of an inspection device for other techniques (e.g., a detector equipped with an optical camera).

[0071] In some embodiments, as shown in Figures 5 and 6, the first detector may include one or more optical elements, such as focusing lenses that can be configured to change the magnification of light and / or beams. In another embodiment, as shown, the detector 131 may optionally include a first focusing lens 513 positioned in the middle of the second optical path 135, and the beam splitter 505 is positioned between the first focusing lens 513 and a plurality of wavefront sensors (e.g., a first wavefront sensor 501, a second wavefront sensor 503). The first focusing lens, if provided, may be configured to change the magnification of light traveling along the first optical path 125, thereby changing the magnification of the plurality of beams. In another embodiment, as shown in Figure 5, the detector may optionally include a second focusing lens 517 positioned between the beam splitter 505 and the first wavefront sensor 501. In another embodiment, as shown in Figure 6, the detector 131 may include a second focusing lens 603 positioned between the beam splitter 505 and the first wavefront sensor 501, and be configured to change the magnification of the first beam 507 among a plurality of beams. For example, the second focusing lens 603 may be configured to change the magnification of the first beam 507 among a plurality of beams, but not to change the magnification of another beam (e.g., the second beam 509) among a plurality of beams. This allows the magnification of the first beam 507 among a plurality of beams to be changed relative to the magnification of another beam (e.g., the second beam 509). In yet another embodiment, the detector 131 may include both the first focusing lens 513 and the second focusing lenses 517 and 603.

[0072] In some embodiments, as shown in Figures 5 and 6, the detector 131 may include a third focusing lens 515 positioned between the beam splitter 505 and the second wavefront sensor 503, configured to change the magnification of the second beam 509 among a plurality of beams. In another embodiment, the third focusing lens 515 may be configured to change the magnification of the second beam 509 among a plurality of beams, but not to change the magnification of another beam (e.g., the first beam 507) among a plurality of beams. This allows the magnification of the second beam 509 to be changed relative to the magnification of another beam (e.g., the first beam 507). In yet another embodiment, the detector 131 may include both the first focusing lens 513 and the third focusing lens 515. In yet another embodiment, the detector 131 may include both the second focusing lenses 517, 603 and the third focusing lens 515. In yet another embodiment, the detector 131 may include a first focusing lens 513, a second focusing lens 517, 603, and a third focusing lens 515.

[0073] In some embodiments, the first focusing lens 513, the second focusing lenses 517, 603, and / or the third focusing lens 515 may be configured to magnify the light and / or beams of multiple beams by about 2 times or more, about 5 times or more, about 10 times or more, about 50 times or less, about 30 times or less, or about 20 times or less. In some embodiments, the first focusing lens 513 and / or the second focusing lenses 517, 603 may be configured to magnify the light and / or beams of multiple beams in the range of about 2 times to about 50 times, about 5 times to about 50 times, about 10 times to about 50 times, about 10 times to about 30 times, about 10 times to about 20 times, or any range or partial range in between.

[0074] In some embodiments, the total magnification of the first beam 507 from the first focusing lens 513 and / or the second focusing lenses 517, 603 may be, if provided, about 2x or more, about 5x or more, about 10x or more, about 50x or less, about 30x or less, or about 20x or less. In some embodiments, the total magnification of the first beam 507 from the first focusing lens 513 and / or the second focusing lenses 517, 603 may be, if provided, in the range of about 2x to about 50x, about 5x to about 50x, about 10x to about 50x, about 10x to about 30x, about 10x to about 20x, or any range or partial range between these.

[0075] In some embodiments, the magnification of the first beam 507 among the multiple beams may differ from the magnification of the second beam 509 among the multiple beams. In another embodiment, the magnification of the first beam 507 as a percentage of the magnification of the second beam 509 among the multiple beams may be about 150% or more, about 200% or more, about 400% or more, about 1000% or less, about 800% or less, or about 600% or less. In another embodiment, the magnification of the first beam 507 as a percentage of the magnification of the second beam 509 among the multiple beams may be in the range of about 150% to about 1000%, about 200% to about 1000%, about 200% to about 800%, about 200% to about 600%, about 400% to about 1000%, about 400% to about 800%, about 400% to about 600%, or any range or partial range between these. In another embodiment, the magnification of the second beam 509 among the multiple beams, as a percentage of the magnification of the first beam 507 among the multiple beams, may be about 150% or more, about 200% or more, about 400% or more, about 1000% or less, about 800% or less, or about 600% or less. In another embodiment, the magnification of the second beam 509 among the multiple beams, as a percentage of the magnification of the first beam 507 among the multiple beams, may be in the range of about 150% to about 1000%, about 200% to about 1000%, about 200% to about 800%, about 200% to about 600%, about 400% to about 1000%, about 400% to about 800%, about 400% to about 600%, or any range or partial range between these. Providing a first beam with a different magnification than the second beam 509 may enable simultaneous measurement of a wide range of feature sizes and / or reduce the need for subsequent inspection (e.g., reinspection) of those features.

[0076] In some embodiments, as shown in Figures 1 and 2, the device 101 may include a controller 119 that can be connected to a detector 131 by a second communication path 133. In another embodiment, the signal detected by the detector 131 (e.g., a wavefront sensor) may be transmitted to the controller 119 along the second communication path 133. In yet another embodiment, the controller 119 may be configured to adjust the magnification, position, orientation, and / or data acquisition rate of the detector 131, for example, using the second communication path 133. In yet another embodiment, as shown, the controller 119 may be connected to an illumination source 121 by a first communication path 123. In yet another embodiment, the controller 119 may be configured to adjust the position and / or orientation, and / or the type of light emitted from the illumination source 121. It should be understood that the first communication path 123 and / or the second communication path 133 may be a physical connection or a wireless connection, as will be described below.

[0077] As used herein, the term “controller” may include all devices, equipment, and machines for processing data (including, for example, a programmable processor, a computer, or multiple processors or computers). A processor may include, in addition to hardware, code that creates an execution environment for the computer program in question, such as processor firmware, a protocol stack, a database management system, an operating system, or code comprising one or more of these. In some embodiments, a controller may consist of and / or be implemented as digital electronic circuits, or computer software, firmware, or hardware (including structures disclosed herein and their structural equivalents or one or more of them). Embodiments of controllers described herein may be implemented as one or more computer program products (e.g., one or more modules of a set of computer program instructions encoded on a tangible program medium to control the execution or operation of a data processing device). The tangible program medium may be a computer-readable medium. The computer-readable medium may be a machine-readable storage device, a machine-readable storage board, a memory device, or one or more of these. Computer programs (also known as programs, software, software applications, scripts, or code) are written in any form of programming language (including compiled or runtime-interpreted languages, or declarative or procedural languages) and can be distributed in any form (as standalone programs, modules, components, subroutines, or other units suitable for use in a computer environment). Computer programs do not necessarily correspond to files in a file system. A program may be stored in part of a file that holds other programs or data (e.g., one or more scripts stored within a markup language document), in a single file dedicated to the program in question, or in a series of linked files (e.g., files storing one or more modules, subprograms, or code portions).Computer programs can be distributed to run on a single computer or on multiple computers located in one place or distributed across multiple locations and interconnected by a communication network. The processes described in this document may be executed by one or more programmable processors that run one or more computer programs that function by processing input data and producing output. Alternatively, the processes and logic flows may be executed by dedicated logic circuits, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits), and the devices may be implemented as such dedicated logic circuits. Processors suitable for executing computer programs include, by example, general-purpose and dedicated microprocessors, and any one or more processors in any type of digital computer. Typically, a processor receives instruction sets and data from read-only memory, random-access memory, or both. Essential elements of a computer are a processor for executing instruction sets and one or more data memory devices for storing instruction sets and data. Typically, a computer also includes one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, or is operationally connected for receiving data from them, transferring data to them, or both. However, a computer is not required to have such devices. Furthermore, computers can be embedded in other devices, such as mobile phones and personal digital assistants (PDAs). Computer-readable media suitable for storing computer program instructions and data include all forms of data memory, including non-volatile memory, media, and memory devices, such as semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. Processors and memory may be supplemented or incorporated by dedicated logic circuits.The embodiments described herein may be implemented on a computer having a display device for displaying information to the user, such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, and a keyboard and pointing device, such as a mouse or trackball, or a touchscreen, through which the user can provide input to the computer, in order to enable interaction with the user. Other types of devices may also be used to enable interaction with the user. For example, user input may be received in any form, including acoustic, voice, or haptic input. The embodiments described herein may be implemented on a computer system having a graphical user interface or web browser through which a user can interact with embodiments of the subject matter described herein, for example, a data server or middleware component, such as an application server or a front-end component, or any combination of one or more such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication, such as a communication network. Embodiments of a communication network include local area networks (LANs) and wide area networks (WANs), such as the Internet. A computer system may include clients and servers. Clients and servers are generally geographically separated from each other and typically interact via a communication network. The client-server relationship arises from computer programs running on each computer that have a client-server relationship with each other.

[0078] In some embodiments, as shown in Figures 1 and 2, the apparatus 101 may include a reflector 115 having a reflective surface 117. In another embodiment, the reflector 115 may consist of an inherently reflective material, such as aluminum, steel, or silver. In yet another such embodiment, the reflector 115 may consist of a material that is reflective when placed in close proximity to another material having a different refractive index, such as polyethylene terephthalate (PET) or polycarbonate (PC). In yet another embodiment, the reflector 115 may have an average reflectance of about 90% or more, about 95% or more, about 96% or more, or about 98% or more over a wavelength range of about 400 nm to about 700 nm. In some embodiments, as shown, the reflective surface 117 of the reflector 115 may face a sample 103 (e.g., a glass substrate), and the sample 103 (e.g., a glass substrate) may have a first main surface 105, a second main surface 107, and a thickness 109 between the first main surface 105 and the second main surface 107. As shown in Figures 1 and 2, the reflector 115 may face the second main surface 107 of the sample 103. In some embodiments, the reflector 115 may be configured to reflect light from the illumination source 121. In another embodiment, the reflector may be configured to reflect light traveling along the first optical path 125 and incident on the reflective surface 117 so that the light passes through the sample 103 (e.g., the second main surface 107, thickness 109, and first main surface 105 of the sample 103) and travels along the second optical path 135 toward the detector 131. Throughout this disclosure, a reflector can reflect light by reflecting at least a portion of the light emitted from the illumination source.

[0079] As shown in Figures 1-4, the devices 101, 301 may have a measuring plane 111. As used in this document, the measuring plane has a target position configured to characterize (e.g., measure) the device. Referring to Figure 1, the measuring plane 111 includes a target position 141 on the first principal surface 105 and extends in a first direction 113 (indicated as the z direction) and a second direction (indicated as the x direction). In some embodiments, the target position 141 may be a position on and / or within the sample 103 that the devices 101, 301 may be configured to measure. In some embodiments, the measuring plane 111 may extend parallel to the first principal surface 105 and / or the second principal surface 107 of the sample 103. In another embodiment, as shown in Figures 1-4, the first principal surface 105 may extend along the measuring plane 111.

[0080] In some embodiments, the sample 103 may have a thickness 109 defined between a first main surface 105 and a second main surface 107 opposite to it. In other embodiments, the thickness 109 may be about 25 μm or more, about 100 μm or more, about 200 μm or more, about 400 μm or more, less than about 10 millimeters (mm), less than about 5 mm, less than about 2 mm, or less than about 1 mm. In other embodiments, the thickness 109 may be in the range of about 25 μm to about 10 mm, about 100 μm to about 10 mm, about 200 μm to about 5 mm, about 400 μm to about 2 mm, about 400 μm to about 1 mm, about 25 μm to about 5 mm, about 25 μm to about 2 mm, about 25 μm to about 1 mm, about 100 μm to about 1 mm, or any range or partial range between these. In some embodiments, the sample 103 may have a length that traverses the first main surface 105 in a first direction 113 (indicated as the z direction). In some embodiments, the sample 103 may have a width in a direction perpendicular to its length (a second direction indicated as the x direction). In another embodiment, the dimensions of the sample (e.g., length, width) may match the dimensions of a consumer electronics product. In some embodiments, the sample may be a consumer electronics product and / or be configured to be included in a consumer electronics product. The consumer electronics product may comprise a glass-based portion and further comprise electrical components that are at least partially contained within a housing. The electrical components may include a controller, memory, and a display. The display may be located on or near the front of the housing. The consumer electronics product may comprise a cover substrate that covers the display.In some embodiments, sample 103 may be a glassy sample. As used herein, “glassy” includes both glass and glass ceramic, where glass ceramic has one or more crystalline phases and an amorphous residual glass phase. Glassy materials become or are made of glass or glass ceramic when cooled or already cooled, and / or become glass ceramic materials after further processing. Glassy materials (e.g., glassy substrates) may include amorphous materials (e.g., glass) and optionally one or more crystalline materials (e.g., ceramics). Amorphous materials and glassy materials may be strengthened. As used herein, the term “strengthened” may refer to materials that have been chemically strengthened, for example by ion exchange of larger ions with smaller ions within the surface of the substrate, as described below. However, other strengthening methods known in the art, such as tempering or processes that utilize mismatches in thermal expansion coefficients between parts of the substrate to generate compressive stress and central tension regions, may be used to form strengthened substrates. Several representative glass-based materials that do not contain or contain lithium oxide include soda-lime glass, alkali-aluminosilicate glass, alkali-containing borosilicate glass, alkali-containing aluminoborosilicate glass, alkali-containing phosphate silicate glass, and alkali-containing aluminophosphate silicate glass. In one or more embodiments, the glass-based material may contain SiO2 in the range of about 40 mol% to about 80 mol%, Al2O3 in the range of about 10 mol% to about 30 mol%, B2O3 in the range of 0 mol% to about 10 mol%, ZrO2 in the range of 0 mol% to about 5 mol%, P2O5 in the range of 0 mol% to about 15 mol%, TiO2 in the range of 0 mol% to about 2 mol%, R2O in the range of 0 mol% to about 20 mol%, and RO in the range of 0 mol% to about 15 mol%. As used in this document, R2O may refer to alkali metal oxides, such as Li2O, Na2O, K2O, Rb2O, and Cs2O. As used in this book, RO can refer to MgO, CaO, SrO, BaO, and ZnO.In some embodiments, the glass-based material may optionally further contain Na2SO4, NaCl, NaF, NaBr, K2SO4, KCl, KF, KBr, As2O3, Sb2O3, SnO2, Fe2O3, MnO, MnO2, MnO3, Mn2O3, Mn3O4, and Mn2O7 in amounts ranging from 0 mol% to about 2 mol%. "Glass ceramic" includes materials made by controlled glass crystallization. In some embodiments, glass ceramic has a degree of crystallinity of about 1% to about 99%. Suitable examples of glass ceramics include Li2O-Al2O3-SiO2 system (i.e., LAS system) glass ceramics, MgO-Al2O3-SiO2 system (i.e., MAS system) glass ceramics, ZnO×Al2O3×nSiO2 (i.e., ZAS system), and / or glass ceramics having a main crystalline phase including β-quartz solid solution, β-siecite, cordierite, feldspar, and / or lithium disilicate. Glass ceramic materials may be strengthened using strengthening treatments described herein. In one or more embodiments, the MAS system glass ceramic substrate may be strengthened in a Li2SO4 molten salt, 2Li. + Mg 2+ An exchange with this may occur.

[0081] In some embodiments, sample 103 may be optically transparent. As used in this document, “optically transparent” or “optically clear” means an average transmittance of 70% or more through a 1.0 mm thick piece of material in the wavelength range of 400 nm to 700 nm. In some embodiments, an “optically transparent material” or “optically clear material” may have an average transmittance of 75% or more, 80% or more, 85% or more, 90% or more, 92% or more, 94% or more, or 96% or more through a 1.0 mm thick piece of material in the wavelength range of 400 nm to 700 nm. The average transmittance in the wavelength range of 400 nm to 700 nm is calculated by measuring the transmittance at integer wavelengths from approximately 400 nm to approximately 700 nm and averaging the measured values.

[0082] In some embodiments, sample 103 may have a first refractive index. The first refractive index may be a function of the wavelength of light passing through the sample. For light of the first wavelength, the refractive index of the material is defined as the ratio of the speed of light in a vacuum to the corresponding speed of light in the material. Although we do not wish to be constrained by theory, if light of the first wavelength is incident from air onto the surface of the sample at a first angle, refracted at the sample surface, and propagates through the sample at a second angle, the refractive index of the sample can be calculated using the ratio of the sine of the first angle to the sine of the second angle. Both the first and second angles are measured with respect to the normal to the surface of the optically transparent adhesive. In some embodiments, the first refractive index of the sample may be about 1 or greater, about 1.3 or greater, about 1.4 or greater, about 1.5 or greater, about 3 or less, about 2 or less, about 1.7 or less, or about 1.6 or less. In some embodiments, the first refractive index of the sample may be in the range of about 1 to about 3, about 1 to about 2, about 1 to about 1.7, about 1.3 to about 3, about 1.3 to about 2, about 1.3 to about 1.7, about 1.4 to about 2, about 1.4 to about 1.7, about 1.4 to about 1.6, about 1.5 to about 1.6, or any range or partial range between these.

[0083] In some embodiments, light may be configured to pass through features of the sample being measured. Throughout this disclosure, light may pass through the thickness and / or features of the sample if at least a portion of the light emitted from the illumination source passes through the thickness and / or features of the sample. In another embodiment, as shown in Figure 4, a surface feature 401 in the optical path (e.g., second optical path 135) may have a height 403 and / or width 405 that can be measured using the apparatus 101, 301. For example, the surface feature may affect the surface contour of the sample. In yet another embodiment, the surface feature may be a blister, bubble, bump, crack, depression, microcrack, and / or wrinkle. In yet another embodiment, light may be configured to pass through subsurface features. In yet another embodiment, the apparatus may be configured to measure subsurface features even if the measurement plane coincides with the surface of the sample (e.g., the first primary surface). In yet another embodiment, although not shown, the measurement plane may pass through subsurface features. For example, as shown in Figure 4, the subsurface feature may be an inclusion 411 below the first primary surface 105 of the sample 103. As used in this book, the inclusions consist of localized concentrations of a material having a different refractive index, clarity, hardness, Young's modulus, and / or coefficient of thermal expansion compared to the whole sample. In some embodiments, the inclusions may consist of gases, such as air, oxygen, nitrogen, hydrogen, carbon dioxide, or a combination thereof. In some embodiments, the inclusions may consist of metals, such as platinum, tin, rhodium, rhenium, osmium, palladium, iridium, or a combination thereof.

[0084] As shown in Figures 1-3, the measuring plane 111 may be positioned between the first region 102 and the second region 104. As shown, the first region 102 may face the first main surface 105 of the sample 103, and the second region 104 may face the second main surface 107 of the sample 103. In some embodiments, as shown in Figure 3, the illumination light source 121 may be positioned within the second region 104 and the detector 131 may be positioned within the first region 102. In some embodiments, as shown in Figures 1 and 2, the illumination light source 121 and the detector 131 may be positioned within the first region 102. In another embodiment, the reflector 115 may be positioned within the second region 104. In another embodiment, the apparatus 101 may be configured to maintain a constant distance between the illumination light source 121 and the detector 131. For example, as shown in Figures 1 and 2, the illumination light source 121 and the detector 131 may be mounted on a common support 151. Providing a detector with one or more wavefront sensors and an illumination source in the first region opposite to the second region containing the reflector, and having a measurement plane (e.g., a glass substrate) between the first region and the second region 104, can reduce (e.g., mitigate) the alignment challenges between the illumination source and the wavefront sensors. Furthermore, providing a common support for both the illumination source and the wavefront sensors allows alignment to be maintained even when susceptible to vibration or intentionally moved.

[0085] In some embodiments, as shown in Figures 1 and 2, angle A may be defined between the first optical path 125 and the second optical path 135. In another embodiment, angle A may be about 0.1° or more, about 0.5° or more, about 1° or more, about 2° or more, about 25° or less, about 15° or less, about 5° or less, or about 2° or less. In another embodiment, angle A may be in the range of about 0.1° to about 25°, about 0.1° to about 15°, about 0.1° to about 5°, about 0.1° to about 2°, about 0.5° to about 2°, about 1° to about 2°, about 5° to about 15°, about 1° to about 15°, about 1° to about 5°, about 2° to about 5°, or any range or partial range between them. In another embodiment, as shown in Figures 1 and 2, the illumination source 121 may be rotatable in the first direction 127. In another embodiment, as shown in Figures 1 and 2, the detector may be rotatable in a second direction 137 opposite to the first direction 127. In yet another embodiment, the device may be configured to rotate the illumination source 121 in the first direction 127 and the detector 131 in the second direction 137, thereby increasing the path distance 129 and / or detection distance 139.

[0086] As used in this book, the path distance is defined as the minimum distance between the illumination light source and the measurement plane. For example, as shown in Figures 1-3, the path distance 129 may be defined between the illumination light source 121 and the measurement plane 111. In some embodiments, the path distance 129 may be adjustable. In other embodiments, the path distance 129 may be about 10 mm or more, about 50 mm or more, about 100 mm or more, about 500 mm or more, about 10 meters or less, about 5 meters or less, or about 1 meter or less. In another embodiment, the path distance 129 may be in the range of approximately 10 mm to approximately 10 m, approximately 10 mm to approximately 5 m, approximately 10 mm to approximately 1 meter, approximately 50 mm to approximately 1 meter, approximately 100 mm to approximately 1 meter, approximately 500 mm to approximately 1 meter, approximately 500 mm to approximately 10 m, approximately 100 mm to approximately 10 m, approximately 500 mm to approximately 10 m, approximately 500 mm to approximately 5 m, approximately 500 mm to approximately 2 m, or any range or partial range between these. In some embodiments, the path distance 129 may be approximately equal to the distance between the illumination light source 121 and the first main surface 105 of the sample 103. Adjusting the distance from the measurement plane may allow for the distinction of different types of features (e.g., surface contours, blistering, gaseous inclusions, metallic inclusions).

[0087] As used in this book, the detection distance is defined as the minimum distance between the detector and the measuring plane. For example, as shown in Figures 1 and 2, the detection distance 139 may be defined between the detector 131 located in the first region 102 and the measuring plane 111. For example, as shown in Figure 3, the detection distance 303 may be defined between the detector 131 located in the second region 104 and the measuring plane 111. In another embodiment, the detection distances 139, 303 may be approximately 10 mm or more, approximately 50 mm or more, approximately 100 mm or more, approximately 500 mm or more, approximately 10 meters or less, approximately 5 meters or less, or approximately 1 meter or less. In another embodiment, the detection distances 139, 303 may be in the range of approximately 10 mm to approximately 10 m, approximately 10 mm to approximately 5 m, approximately 10 mm to approximately 1 meter, approximately 50 mm to approximately 1 meter, approximately 100 mm to approximately 1 meter, approximately 500 mm to approximately 1 meter, approximately 500 mm to approximately 10 m, approximately 100 mm to approximately 10 m, approximately 500 mm to approximately 10 m, approximately 500 mm to approximately 5 m, approximately 500 mm to approximately 2 m, or any range or partial range between these. In some embodiments, the detection distances 139, 303 may be approximately equal to the distance between the detector 131 and the first main surface 105 of the sample 103. Adjusting the distance from the measurement plane may be used to adjust the size of features that can be accurately and quantitatively detected.

[0088] An embodiment of a method for measuring the characteristics of a sample (e.g., a glass substrate) according to the present disclosure will be described with reference to the flowchart in Figure 11.

[0089] In the first step 1101 of the method for measuring the characteristics of a sample, the method may begin with supplying the sample 103. In some embodiments, the sample 103 may consist of a glass substrate. In some embodiments, the sample 103 may be supplied by purchase or other means, or by forming it using known methods. In another embodiment, the glass sample or a layer of glass sample may be supplied by forming the sample using various ribbon forming processes, e.g., slot draw, downward draw, fused downward draw, upward draw, compression roll, redraw, or float. In some embodiments, the sample 103 may consist of a glass substrate manufactured in a glass manufacturing apparatus located upstream of the apparatus 101, 301 (e.g., in the opposite direction to direction 113 in Figures 1-3). In some embodiments, the step 1101 of supplying the sample 103 may optionally supply the sample by moving and positioning the sample 103 (e.g., glass substrate) in the direction 113. In another embodiment, as shown in Figures 1 and 2, the direction 113 may be approximately perpendicular to the thickness 109 of the sample 103 (e.g., a glass substrate). If the sample 103 is moved in step 1101, which is the step in supplying the sample 103, as shown in the flowchart of Figure 11, the movement may occur before step 1105 and / or before step 1109, which are described below.

[0090] Following step 1101, the method may proceed to step 1103, in which the illumination source 121 emits light. In some embodiments, the light emitted from the illumination source 121 may travel along the first optical path 125 toward the measurement plane 111. In some embodiments, the illumination source 121 may emit light substantially continuously. In some embodiments, the illumination source 121 may emit one or more light pulses. In some embodiments, the illumination source 121 may emit coherent light. In some embodiments, the path distance 129 between the illumination source 121 and the measurement plane 111 may be within one or more of the ranges described above for the path distance 129.

[0091] Following step 1103, the method may proceed to step 1105, which includes projecting light onto the measurement plane 111. As described above, the measurement plane 111 may extend perpendicular (e.g., vertically) to the thickness 109 of the sample 103 (e.g., a glass substrate) (defined between the first principal surface 105 and the second principal surface 107 and may be within any of the ranges described above for the thickness 109). In some embodiments, as shown in Figures 1 and 2, the measurement plane 111 may be parallel and / or coincident with the first principal surface 105 of the sample 103. In another embodiment, as shown in Figure 1, projecting light onto the measurement plane 111 may further include projecting light onto the first principal surface 105 of the sample 103. In yet another embodiment, as shown in Figure 2, the light may be incident on the measurement plane 111 at a location where the sample 103 (e.g., the first principal surface 105) is not present.

[0092] After step 1105, the method may proceed to step 1107, which includes reflecting light toward the sample 103 (e.g., a glass substrate). As shown in Figures 1 and 2, reflecting light toward the sample 103 may consist of reflecting light from the reflective surface 117 of the reflector 115. In some embodiments, as shown, the angle between the light incident on the reflective surface 117 and the reflected light may be within one or more of the ranges described above for angle A.

[0093] Following step 1107, the method may proceed to step 1109, which includes propagating light (e.g., reflected light) through the thickness 109 of the sample 103 (e.g., a glass substrate) toward the first main surface 105 of the sample 103. In some embodiments, step 1109 may further include projecting light (e.g., reflected light) onto the second main surface 107 of the sample 103 before propagating the light through the thickness 109 of the sample 103. In some embodiments, step 1109 may include moving the sample 103 (e.g., a glass substrate) in the direction 113 while the light is propagating through the thickness 109 of the sample. In another embodiment, as described above and shown in Figures 1-3, the direction 113 may be approximately perpendicular (e.g., perpendicular) to the thickness 109 of the sample 103 (e.g., a glass substrate).

[0094] Following step 1109, the method may proceed to step 1111, which involves propagating light (e.g., reflected light) through a target location 141 on the first main surface 105 of the sample 103 (e.g., a glass substrate), as shown in Figures 1-3. In some embodiments, the measuring plane 111 may include the target location 141 on the first main surface 105. In some embodiments, as shown in Figure 4, the target location may include a surface feature 401 to be measured. As described above, the surface feature affects the surface contour of the sample and may be a blister, bubble, bump, crack, depression, microcrack, and / or wrinkle. In some embodiments, as shown in Figure 4, the light may be configured to pass through subsurface features before propagating through the target location 141 on the first main surface 105 of the sample 103. In yet another embodiment, the apparatus may be configured to measure subsurface features even if the measuring plane coincides with the surface of the sample (e.g., the first main surface). In yet another embodiment, although not shown, the measuring plane may pass through subsurface features, such as impurities consisting of gases (e.g., air, oxygen, nitrogen, hydrogen, carbon dioxide) and / or metals (e.g., platinum, tin, rhodium, rhenium, osmium, palladium, iridium).

[0095] Following step 1111, the method may proceed to step 1113, which includes splitting the light (e.g., reflected light) into multiple beams. In some embodiments, as shown in Figures 5 and 6, the light may propagate along a second optical path 135 and be incident on a beam splitter 505. In some embodiments, as shown, the light may be incident on an optical element, such as a first focusing lens 513 that can change the magnification and / or focus of the light. In some embodiments, as described above, the light may be split by the beam splitter 505 into multiple beams, including a first beam 507 and a second beam 509. For example, as shown, the first beam 507 may be directed to a first wavefront sensor 501 and / or the second beam 509 may be directed to a second wavefront sensor 503.

[0096] Following step 1113, the method may proceed to step 1115, which involves changing the magnification of at least one of the multiple beams. In some embodiments, as shown in Figures 5 and 6, the magnification of the first beam 507 may be changed by the second focusing lenses 517, 603. In another embodiment, the magnification of the first beam 507 from the first focusing lens 513 and / or the second focusing lenses 517, 603 may be within one or more of the ranges described above (e.g., from a magnification of 2× to a magnification of approximately 50×). In some embodiments, as shown in Figures 5 and 6, the third focusing lens 515 may change the magnification of the second beam 509. In another embodiment, the magnification of the second beam 509 from the first focusing lens 513 and / or the third focusing lens 515 may be within one or more of the ranges described above (e.g., from a magnification of approximately 2× to a magnification of approximately 50×). In another embodiment, the third focusing lens 515 can change the magnification of the second beam 509 relative to the magnification of the first beam 507 (e.g., from the second focusing lenses 517, 603). In yet another embodiment, the magnification of the first beam 507 is greater than the magnification of the second beam 509, and the magnification of the first beam 507 as a percentage of the magnification of the second beam 509 may be within one or more of the ranges described above (e.g., from about 150% to about 1000%). In yet another embodiment, the magnification of the second beam 509 is greater than the magnification of the first beam 507, and the magnification of the second beam 509 as a percentage of the magnification of the first beam 507 may be within one or more of the ranges described above (e.g., from about 150% to about 1000%).

[0097] Following step 1115, the method may proceed to step 1117, which includes detecting light (e.g., reflected light, transmitted light) using at least one wavefront sensor of detector 131. Throughout this disclosure, if at least one wavefront sensor detects at least a portion of the light emitted from an illumination source, the detector may reflect light. As described above, light propagating through the target position 141 may be detected using at least one wavefront sensor of detector 131. In some embodiments, the detection distance 139 between detector 131 and the measurement plane 111 may be within one or more of the ranges described above for the detection distance 139. In some embodiments, as shown in Figures 5 and 6, light may be detected by the first wavefront sensor 501 when the first wavefront sensor 501 detects the first beam 507 among a plurality of beams. In another embodiment, as shown in Figure 6, the light (e.g., the first beam 507) may be further detected by the optical camera 601. In some embodiments, as shown in Figures 5 and 6, when the second wavefront sensor 503 detects the second beam 509 among a plurality of beams, the light can be detected using the second wavefront sensor 503.

[0098] Step 1117 may further include generating a first signal with at least one wavefront sensor based on light (e.g., detected light, transmitted light, detected light). In some embodiments, the signal may be generated by a first wavefront sensor 501 and / or a second wavefront sensor 503. In some embodiments, the first signal may consist of a sequence of multiple neutral positions and their corresponding spot distances as described above with respect to Figures 7-10. In some embodiments, the first signal may be transmitted to a controller 119 along a second communication path 133. In some embodiments, the first signal may be a first signal generated by at least one wavefront sensor with respect to a sample 103 at its current position. In some embodiments, after the sample 103 (e.g., a glass substrate) has been moved in step 1101 before the first signal is generated by at least one wavefront sensor, no signal may be generated by that at least one wavefront sensor. In some embodiments, after the sample 103 (e.g., a glass substrate) is moved in step 1101 before the light passes through the thickness 109 in step 1109, a signal may not be generated by at least one wavefront sensor. In some embodiments, the first signal may be a first signal generated by at least one wavefront sensor with respect to the sample 103 at its current position.

[0099] After step 1117, the method may proceed to step 1119, which includes adjusting the detection distance 139 between the measurement plane 111 (e.g., the first main surface 105) of the sample 103 and the detector 131. In some embodiments, step 1119 may include adjusting the path distance 129 between the measurement plane 111 (e.g., the first main surface 105) and the illumination light source 121. In another embodiment, the path distance 129 may be adjusted by approximately the same amount as the detection distance 139 is adjusted. In some embodiments, the detection distance 139 may be increased. Although we do not wish to be constrained by theory, wavefront distortion due to subsurface features may attenuate faster than wavefront distortion due to surface features. Therefore, by comparing light detected at two or more different detection distances 139 (e.g., the generated signal), wavefront distortion due to surface features and wavefront distortion due to subsurface features can be separated.

[0100] Following step 1119, the method may proceed to step 1121, which includes generating a second signal. In some embodiments, the light may consist of multiple pulses. Of the multiple pulses, a first pulse may be detected by a detector 131 equipped with at least one wavefront sensor (e.g., a first wavefront sensor 501, a second wavefront sensor 503) to generate a first signal. In another embodiment, a second pulse of the multiple pulses may be emitted from an illumination source 121. In yet another embodiment, the second pulse may be projected onto the measurement plane 111 before being reflected from the reflective surface 117 of the reflector 115 toward the sample 103 (e.g., a glass substrate). The second pulse (e.g., the reflected second pulse) may propagate through the thickness of the sample 103 (e.g., a glass substrate). The second pulse may propagate through a target position 141 on the first main surface 105 of the sample 103 (e.g., a glass substrate). The second pulse propagating through the target position 141 may be detected using a detector 131 equipped with at least one wavefront sensor. Detector 131, which includes at least one wavefront sensor, can generate a second signal based on the detected second pulse.

[0101] Following step 1121, the method may proceed to step 1123, which involves moving the sample 103 in the direction 113. In some embodiments, as shown in Figures 1-3, step 1123 may involve moving the sample 103 (e.g., a glass substrate) in the direction 113 to position the sample 103. In another embodiment, as shown in Figures 1-3, the direction 113 may be approximately perpendicular (e.g., vertical) to the thickness 109 of the sample 103 (e.g., a glass substrate). As shown in the flowchart of Figure 11, the movement in step 1123 may occur after detecting light propagating through the target position 141 in step 1117. In some embodiments, the measurement time may be defined as the interval between (1) the end of the movement of the sample 103 (e.g., a glass substrate) in step 1101, before the light propagates through the thickness 109 in step 1109, and (2) the start of the movement of the sample 103 (e.g., a glass substrate) in step 1123, after the detection of light propagated through the target position 141 using at least one wavefront sensor (e.g., a first wavefront sensor 501, a second wavefront sensor 503) in step 1117. In other embodiments, the measurement time may be about 10 microseconds (μs) or more, about 100 μs or more, about 1 milliseconds (ms) or more, about 10 ms or more, about 100 ms or less, about 50 ms or less, about 20 ms or less, or about 10 ms or less. In another embodiment, the measurement time may be in the range of approximately 10 μs to approximately 100 ms, approximately 100 μs to approximately 100 ms, approximately 1 ms to approximately 100 ms, approximately 1 ms to approximately 50 ms, approximately 10 ms to approximately 50 ms, approximately 10 ms to approximately 20 ms, or any range or partial range between these.

[0102] Following step 1123, the method may proceed to step 1125, which includes measuring features using at least a first signal. In some embodiments, step 1125 may include measuring features using a first signal and a second signal. In another embodiment, the first signal and the second signal can be compared to more accurately measure surface features and / or subsurface features. In another embodiment, multiple measurements corresponding to multiple detected signals may be combined (e.g., averaged) to generate a composite detected signal. In some embodiments, measuring features may include determining the surface contour of the sample 103 (e.g., a glass substrate) at a target position 141 on the first main surface 105. In some embodiments, measuring features may include determining the height and / or width of features on the sample 103 (e.g., a glass substrate) based on at least a first signal (e.g., a generated first signal). In some embodiments, measuring features may include using at least a first signal and the refractive index of the sample 103 (e.g., a glass substrate).

[0103] In some embodiments, a method for measuring the characteristics of a sample (e.g., a glass substrate) according to the embodiments of this disclosure may proceed sequentially along steps 1101, 1103, 1105, 1107, 1109, 1111, 1113, 1115, 1117, 1119, 1121, 1123, and 1125 as described above. In some embodiments, the method may follow arrow 1102 from step 1103 to step 1109 when using the apparatus 301 shown in Figure 3, for example. In another embodiment, the method following arrow 1102 may omit the reflection of light in step 1105 and / or step 1107, which includes projecting onto the measurement plane 111, when using the apparatus 301 shown in Figure 3. In some embodiments, if the beam splitter 505 in Figures 5, 6 is omitted, and the signal is detected by, for example, one wavefront sensor (e.g., first wavefront sensor 501), the method may follow arrow 1104 from step 1111 to step 1115. In some embodiments, the method can detect light with a single wavefront sensor by following arrow 1106 from step 1111 to step 1117, for example, without splitting the light into multiple beams in step 1113 and / or without changing the magnification of one of the multiple beams in step 1115. In some embodiments, for example, when measuring features based on a first signal, the method can follow arrow 1108 from step 1117 to step 1125. For example, the method following arrow 1108 can omit generating a second signal in step 1121, adjusting the detection distance 139 in step 1119, and / or moving the sample 103 in step 1123. In some embodiments, for example, when multiple signals are generated at the same detection distance 139, the method can follow arrow 1110 from step 1117 to step 1121 by omitting step 1119, which adjusts the detection distance 139. In some embodiments, for example, if the sample 103 is subsequently measured at the same location (e.g., measuring different features at approximately the same location) and / or if the method moves the sample 103 after completion in step 1125, the method may omit the movement of the sample 103 in step 1123 and proceed from step 1121 to step 1125 following arrow 1112.In some embodiments, if a first signal is used to measure a feature and a subsequent signal is used to measure another feature at a different location on the sample, the method may follow arrow 1114 from step 1117 to step 1123. For example, following arrow 1114 may omit step 1121, which generates the second signal, and / or step 1119, which adjusts the detection distance 139. It should be understood that any combination of the above options may be used to measure the features of a sample (e.g., a glass substrate) according to the embodiments of this disclosure. [Examples]

[0104] Various embodiments will be further illustrated by the following examples. Figure 12 shows the accuracy and precision of the apparatus and method of this disclosure for measuring the features of a sample. In Figure 12, the horizontal axis 1201 (e.g., x-axis) is the height in nanometers (nm) of the surface features of a glass substrate measured using a Zygo NewView 9000 profile meter. The vertical axis 1203 (e.g., y-axis) is the height in nanometers (nm) of the surface features of a glass substrate measured using the apparatus shown in Figure 1, where the illumination source 121 was an InGaAs laser diode. For the majority of wavefront measurements of features with heights between 1000 nm and 2250 nm, the detector 131 was a Shack-Hartmann wavefront sensor with a total magnification of 10 ×. For other wavefront sensor measurements, the detector 131 was a 4-wave transverse shearing interferometer with a total magnification of 20 ×, 40 ×, or 100 ×. Data corresponding to the heights of several features measured using the profile meter and wavefront sensor are plotted in Figure 12. Since the measurements from both detectors agree equally well with the profiler measurements, the measurements from the Shack-Hartmann wavefront sensor and the 4-wave transverse shearing interferometer are coupled in Figure 12. A line 1205 with a slope of approximately 1 fits the data points, R 2The value is 0.9977. A linear fit indicates that the apparatus and method of the disclosure can provide measurements that directly correspond to the actual features being measured. A one-to-one correspondence indicates that the apparatus and method of the disclosure can provide quantitative measurements. A small deviation of the point from the line indicates that the apparatus and method of the disclosure can provide accurate measurements.

[0105] The above disclosure provides an apparatus and method for measuring the features of a glass substrate, which reduces the need for recalibration and / or repositioning and enables rapid, in-process quantitative measurement and / or characterization of features, thereby increasing manufacturing efficiency and reducing processing time. Providing at least one wavefront sensor can enable quantitative and accurate measurement of features that is unaffected by vibration and reduces the need for recalibration of the apparatus. Providing a wavefront sensor can enable measurement while the glass substrate is moving and / or after it has been moved. Providing a wavefront sensor can enable rapid (e.g., less than about 100 milliseconds) measurement of features. The wavefront sensor can also be integrated with additional (e.g., existing) inspection equipment (e.g., a camera).

[0106] Providing at least one wavefront sensor can enable measurements at various distances from the measurement plane (e.g., the first primary surface of a glass substrate). Adjusting the distance from the measurement plane can enable the distinction between different types of features (e.g., surface contours, blistering, gaseous inclusions, metallic inclusions). Adjusting the distance from the measurement plane can also be used to adjust the size of features that can be detected accurately and quantitatively. Providing two or more wavefront sensors with different magnifications can enable simultaneous measurement of a wide range of feature sizes. For example, using two or more wavefront sensors with different magnifications can reduce the need for subsequent inspection (e.g., re-inspection) of features. Providing one or more wavefront sensors and an illumination source in the first region opposite the second region containing the reflector, with the measurement plane (e.g., a glass substrate) between the first and second regions, can reduce (e.g., mitigate) the alignment challenges between the illumination source and the wavefront sensor. For example, providing a common support for both the illumination source and the wavefront sensor can maintain alignment even when susceptible to vibration or intentionally moved. The directional terms used in this book, such as up, down, right, left, front, back, top, and bottom, are used only in reference to the illustrations and are not intended to suggest absolute directions.

[0107] It will be understood that various disclosed embodiments may include features, elements, or steps described in relation to those embodiments. It will also be understood that features, elements, or steps described in relation to one embodiment may be replaced or combined with other embodiments by various non-exemplary combinations or rearrangements.

[0108] Furthermore, as used herein, unless explicitly indicated otherwise, the English terms “the,” “a,” or “an” should be understood to mean “at least one” and not to be limited to “only one.” For example, a reference to one part includes embodiments having two or more such parts unless explicitly indicated otherwise by the context. Similarly, “plural” is intended to mean “two or more.”

[0109] As used herein, the term “about” means that quantities, sizes, formulations, parameters, and other quantities and characteristics are not and do not need to be exact, and may be approximate and / or greater or less, as desired, reflecting tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. Ranges may be expressed herein as “about” a particular value to and / or “about” another particular value. When expressing such a range, embodiments include that particular value to and / or that other particular value. Similarly, when a value is expressed as an approximation by the preceding use of “about,” it will be understood that the particular value forms another embodiment. Wherein herein a range number or endpoint is “about” or not, the range number or endpoint is intended to include both “about”-qualified embodiments and “about”-unqualified embodiments. It will also be understood that each range endpoint has meaning in relation to and independently of other endpoints.

[0110] As used herein, the terms “substantial,” “approximately,” and their variations are intended to indicate that a described feature is equal to or approximately equal to a certain value or description, unless otherwise specified. For example, a “approximately planar” surface is intended to indicate a surface that is planar or approximately planar. Also, as above, “approximately equal” is intended to indicate that two values ​​are equal to or approximately equal to each other. In some embodiments, “approximately equal” may mean values ​​within about 10% of each other, for example, within about 5% of each other, or within about 2% of each other.

[0111] Unless otherwise explicitly stated, no method described herein is ever intended to be interpreted as requiring its steps to be performed in a specific order. Therefore, if a method claim does not actually specify the order in which its steps are followed, or if the claim or description does not explicitly state that the steps should be limited to a particular order, no particular order is ever intended to be inferred.

[0112] While various features, elements, or steps of a particular embodiment may be disclosed using the transitional phrase “comprising,” it should be understood that other embodiments are suggested that include features, elements, or steps that may be described using the transitional phrase “consisting” or “consisting essentially of.” Thus, for example, suggested other embodiments of an apparatus that “comprises” A+B+C include embodiments in which the apparatus “consists of” A+B+C, and embodiments in which the apparatus “consists essentially of” A+B+C. As used herein, the terms “comprising” and “including,” and their variations, should be interpreted as synonymous and open-ended unless otherwise indicated.

[0113] The embodiments and features described above are representative and may be provided individually or in any combination with any one or more features of the other embodiments described without departing from the scope of this disclosure.

[0114] It will be apparent to those skilled in the art that various modifications and variations can be made to this disclosure without departing from the gist and scope of this disclosure. Accordingly, where modifications and variations of embodiments fall within the scope of the appended claims and their equivalents, this disclosure is intended to encompass such modifications and variations.

[0115] Preferred embodiments of the present invention are described below in separate sections.

[0116] Embodiment 1 An illumination light source and at least one wavefront sensor are arranged in the first region. A reflector placed in the second region, A measuring plane positioned between the first region and the second region and Equipped with, An apparatus comprising: an illumination light source configured to emit light projected onto the measuring plane; a reflector configured to reflect the light from the illumination light source; and at least one wavefront sensor configured to detect the light reflected by the reflector.

[0117] Embodiment 2 The apparatus according to Embodiment 1, wherein the path distance between the illumination light source and the measuring plane is adjustable.

[0118] Embodiment 3 The apparatus according to any one of embodiments 1 or 2, wherein the detection distance between the at least one wavefront sensor and the measuring plane is adjustable.

[0119] Embodiment 4 The apparatus according to any one of embodiments 1 to 3, wherein the illumination light source is configured to emit light consisting of coherent light.

[0120] Embodiment 5 The apparatus according to any one of embodiments 1 to 4, wherein the illumination light source is configured to emit light consisting of pulses.

[0121] Embodiment 6 The apparatus according to any one of embodiments 1 to 5, wherein the illumination light source consists of a laser.

[0122] Embodiment 7 The apparatus according to any one of embodiments 1 to 6, wherein the at least one wavefront sensor comprises a Shack-Hartmann wavefront sensor.

[0123] Embodiment 8 The apparatus according to any one of embodiments 1 to 6, wherein the at least one wavefront sensor comprises a lateral shearing interferometer.

[0124] Embodiment 9 The apparatus according to Embodiment 8, wherein the aforementioned lateral shearing interferometer is a 4-wave lateral shearing interferometer.

[0125] Embodiment 10 The apparatus according to any one of embodiments 1 to 6, wherein the at least one wavefront sensor comprises a pyramidal wavefront sensor.

[0126] Embodiment 11 The system further comprises a beam splitter configured to split the aforementioned light into multiple beams, The apparatus according to any one of embodiments 1 to 8, wherein the at least one wavefront sensor includes a first wavefront sensor configured to detect a first beam among the plurality of beams and a second wavefront sensor configured to detect a second beam among the plurality of beams.

[0127] Embodiment 12 The apparatus according to embodiment 11, further comprising an optical element configured to change the magnification of the first beam.

[0128] Embodiment 13 The apparatus according to embodiment 12, further comprising a second optical element configured to change the magnification of the second beam relative to the magnification of the first beam.

[0129] Embodiment 14 The apparatus according to any one of embodiments 11 to 13, further comprising an optical camera configured to detect the first beam among the plurality of beams.

[0130] Embodiment 15 A method for measuring the characteristics of a glass substrate, A step of projecting light onto a measuring plane of the glass substrate, wherein the measuring plane extends perpendicular to the thickness of the glass substrate and the thickness is defined between a first main surface and a second main surface of the glass substrate. The steps of reflecting the aforementioned light toward the glass substrate, The steps include: propagating the reflected light through the thickness of the glass substrate toward the first main surface of the glass substrate and through a target position on the first main surface of the glass substrate; The steps include detecting light propagated through the target position using at least one wavefront sensor, The steps include generating a first signal with at least one wavefront sensor based on the detected light, and A method that includes this.

[0131] Embodiment 16 The method according to Embodiment 15, wherein the step of projecting the light onto the measuring plane comprises projecting it onto the first main surface of the glass substrate.

[0132] Embodiment 17 The steps include moving the glass substrate in a direction perpendicular to the thickness of the glass substrate before the light is propagated through the aforementioned thickness, The steps include: detecting the light propagated through the target position using the at least one wavefront sensor, and then moving the glass substrate in a direction perpendicular to the thickness of the glass substrate; The method according to any one of embodiments 15, 16, further including the following.

[0133] Embodiment 18 The method according to Embodiment 17, wherein the glass substrate is moved before the light is propagated through the thickness and before the first signal is generated by the at least one wavefront sensor, and the at least one wavefront sensor does not generate a signal after this point.

[0134] Embodiment 19 The method according to any one of embodiments 17 or 18, wherein the measurement time defined between the end of the movement of the glass substrate before the light propagates through the thickness and the start of the movement of the glass substrate after the detection of the light propagated through the target position using the at least one wavefront sensor is about 100 milliseconds or less.

[0135] Embodiment 20 The method according to any one of embodiments 15 or 16, wherein when the light propagates through the thickness of the glass substrate, the glass substrate moves in a direction perpendicular to the thickness of the glass substrate.

[0136] Embodiment 21 A method for measuring the characteristics of a glass substrate, The steps of propagating light toward the first main surface of the glass substrate, passing through the thickness between the first main surface and the second main surface of the glass substrate and passing through a target position on the first main surface of the glass substrate, The steps include detecting the light propagated through the target position using at least one wavefront sensor, The steps include generating a first signal with at least one wavefront sensor based on the detected light, and Includes, A method wherein, when the light propagates through the thickness of the glass substrate, the glass substrate moves in a direction perpendicular to the thickness of the glass substrate.

[0137] Embodiment 22 A method for measuring the characteristics of a glass substrate, The steps of propagating light toward the first main surface of the glass substrate, passing through the thickness between the first main surface and the second main surface of the glass substrate and passing through a target position on the first main surface of the glass substrate, The steps include detecting the light propagated through the target position using at least one wavefront sensor, The steps include generating a first signal with at least one wavefront sensor based on the detected light, Before the light propagates through the thickness of the glass substrate, the glass substrate is moved in a direction perpendicular to the thickness, The steps include detecting the light propagated through the target position using the at least one wavefront sensor, and then moving the glass substrate in a direction perpendicular to the thickness of the glass substrate. Includes, A method wherein the measurement time defined between the end of the movement of the glass substrate before the light propagates through the thickness and the start of the movement of the glass substrate after the light propagated through the target position is detected using the at least one wavefront sensor is about 100 milliseconds or less.

[0138] Embodiment 23 A step of projecting light onto a measuring plane of the glass substrate, wherein the measuring plane extends perpendicular to the thickness of the glass substrate and the thickness is defined between a first main surface and a second main surface of the glass substrate. The steps of reflecting the light toward the glass substrate before the light propagates through the thickness, The method according to any one of embodiments 21, 22, further including the following.

[0139] Embodiment 24 The method according to any one of embodiments 15 to 23, further comprising the step of determining the height and / or width of the features of the glass substrate based on the generated first signal.

[0140] Embodiment 25 The method according to Embodiment 24, wherein the step of determining the height and / or width of the features of the glass substrate is further based on the refractive index of the glass substrate.

[0141] Embodiment 26 The method according to any one of embodiments 15 to 25, wherein the aforementioned feature is the surface contour of the glass substrate at the target position.

[0142] Embodiment 27 The method according to any one of embodiments 15 to 25, wherein the aforementioned feature is an inclusion beneath the first main surface at the target position of the glass substrate.

[0143] Embodiment 28 The method according to Embodiment 27, wherein the impurity consists of a gas.

[0144] Embodiment 29 The method according to embodiment 27, wherein the impurity consists of metal.

[0145] Embodiment 30 The method according to any one of embodiments 15 to 29, wherein the at least one wavefront sensor comprises a Shack-Hartmann wavefront sensor.

[0146] Embodiment 31 The method according to any one of embodiments 15 to 29, wherein the at least one wavefront sensor comprises a lateral shearing interferometer.

[0147] Embodiment 32 The method according to Embodiment 31, wherein the lateral shearing interferometer is a 4-wave lateral shearing interferometer.

[0148] Embodiment 33 The method according to any one of embodiments 15 to 29, wherein the at least one wavefront sensor comprises a pyramidal wavefront sensor.

[0149] Embodiment 34 The steps include dividing the light propagated through the target position into a plurality of beams, including a first beam and a second beam, The steps of changing the magnification of the first beam and It further includes, The step of detecting the propagated light using the at least one wavefront sensor is: The steps include detecting the first beam with the first wavefront sensor among the at least one wavefront sensor, The steps include detecting the second beam with the second wavefront sensor among the at least one wavefront sensor, and The method according to any one of embodiments 15 to 31, including the method described above.

[0150] Embodiment 35 The step of changing the magnification of the first beam is the method according to Embodiment 34, wherein the magnification is changed in the range of about 2× to about 50×.

[0151] Embodiment 36 The method according to any one of embodiments 34, 35, further comprising the step of changing the magnification of the second beam relative to the magnification of the first beam.

[0152] Embodiment 37 The method according to Embodiment 36, wherein the magnification of the first beam is about 150% to about 1000% of the magnification of the second beam.

[0153] Embodiment 38 The method according to any one of embodiments 34 to 37, further comprising the step of detecting the first beam with an optical camera.

[0154] Embodiment 39 The aforementioned light consists of a first pulse, A step of adjusting the detection distance between the first main surface and the at least one wavefront sensor, The steps include projecting a second pulse onto the measurement plane, The steps include: reflecting the second pulse toward the glass substrate and propagating it through the thickness of the glass substrate; The steps include: propagating the reflected second pulse toward the first main surface of the glass substrate through the target position on the first main surface of the glass substrate; The steps include detecting the second pulse that has propagated through the target position using at least one wavefront sensor, The steps include generating a second signal with at least one wavefront sensor based on the detected second pulse, and The method according to any one of embodiments 15 to 38, further including the above.

[0155] Embodiment 40 The method according to embodiment 39, further comprising the step of measuring the feature using the first signal and the second signal. [Explanation of symbols]

[0156] 101, 301 equipment 102 1st area 103 Samples 104 Second area 105 1st main surface 107 Second main surface 109 Thickness 111 Measuring plane 115 Reflector 119 Controller 121 Lighting source 123 First Communication Channel 125 1st optical path 129 road distance 131 detectors 133 Second Communication Channel 135 Second optical path 139, 303 detection distance 141 Target position 151 Support 401 Surface Features 411 Adulterants 501, 503 Wavefront Sensors 505 Beam Splitter 507, 509 beams 511 Mirror 513, 515, 517 Focusing lenses

Claims

1. An illumination light source and at least one wavefront sensor are arranged in the first region. A reflector placed in the second region, A measurement plane of a glass substrate is positioned between the first region and the second region. Equipped with, The illumination light source is configured to emit light projected onto the measurement plane, the reflector is configured to reflect the light from the illumination light source, and the at least one wavefront sensor is configured to detect the light reflected by the reflector. The system further comprises a beam splitter configured to split the aforementioned light into multiple beams, The at least one wavefront sensor includes a first wavefront sensor configured to detect a first beam among the plurality of beams and a second wavefront sensor configured to detect a second beam among the plurality of beams. An optical element configured to change the magnification of the first beam, A second optical element configured to change the magnification of the second beam relative to the magnification of the first beam, A device that further enhances this feature.

2. The apparatus according to claim 1, wherein the path distance between the illumination light source and the measuring plane is adjustable.

3. The apparatus according to claim 1, wherein the detection distance between the at least one wavefront sensor and the measuring plane is adjustable.

4. The apparatus according to claim 1, wherein the illumination light source is a laser.

5. The apparatus according to claim 1, further comprising an optical camera configured to detect the first beam among the plurality of beams.

6. A method for measuring the characteristics of a glass substrate, A step of projecting light onto a measuring plane of the glass substrate, wherein the measuring plane extends perpendicular to the thickness of the glass substrate and the thickness is defined between a first main surface and a second main surface of the glass substrate. The steps of reflecting the aforementioned light toward the glass substrate, The steps include: propagating the reflected light through the thickness of the glass substrate toward the first main surface of the glass substrate and through a target position on the first main surface of the glass substrate; The steps include detecting light propagated through the target position using at least one wavefront sensor, The steps include generating a first signal with at least one wavefront sensor based on the detected light, The steps include dividing the light propagated through the target position into a plurality of beams, including a first beam and a second beam, The step of changing the magnification of the first beam, A step of changing the magnification of the second beam relative to the magnification of the first beam. Includes, The step of detecting the propagated light using the at least one wavefront sensor is: The steps include detecting the first beam with the first wavefront sensor among the at least one wavefront sensor, The steps include detecting the second beam with the second wavefront sensor among the at least one wavefront sensor, and Methods that include...

7. The steps include moving the glass substrate in a direction perpendicular to the thickness of the glass substrate before the light is propagated through the aforementioned thickness, The steps include: detecting the light propagated through the target position using the at least one wavefront sensor, and then moving the glass substrate in a direction perpendicular to the thickness of the glass substrate; The method according to claim 6, further comprising:

8. The method according to claim 6, wherein when the light propagates through the thickness of the glass substrate, the glass substrate moves in a direction perpendicular to the thickness of the glass substrate.

9. A method for measuring the characteristics of a glass substrate, The steps of propagating light toward the first main surface of the glass substrate, passing through the thickness between the first main surface and the second main surface of the glass substrate and passing through a target position on the first main surface of the glass substrate, The steps include detecting the light propagated through the target position using at least one wavefront sensor, The steps include generating a first signal with at least one wavefront sensor based on the detected light, The steps include dividing the light propagated through the target position into a plurality of beams, including a first beam and a second beam, The step of changing the magnification of the first beam, A step of changing the magnification of the second beam relative to the magnification of the first beam, Includes, The step of detecting the propagated light using the at least one wavefront sensor is: The steps include detecting the first beam with the first wavefront sensor among the at least one wavefront sensor, The steps include detecting the second beam with the second wavefront sensor among the at least one wavefront sensor, and Includes, A method wherein, when the light propagates through the thickness of the glass substrate, the glass substrate moves in a direction perpendicular to the thickness of the glass substrate.

10. A method for measuring the characteristics of a glass substrate, The steps of propagating light toward the first main surface of the glass substrate, passing through the thickness between the first main surface and the second main surface of the glass substrate and passing through a target position on the first main surface of the glass substrate, The steps include detecting the light propagated through the target position using at least one wavefront sensor, The steps include generating a first signal with at least one wavefront sensor based on the detected light, Before the light propagates through the thickness of the glass substrate, the glass substrate is moved in a direction perpendicular to the thickness, The steps include detecting the light propagated through the target position using at least one wavefront sensor, and then moving the glass substrate in a direction perpendicular to the thickness of the glass substrate, The steps include dividing the light propagated through the target position into a plurality of beams, including a first beam and a second beam, The step of changing the magnification of the first beam, A step of changing the magnification of the second beam relative to the magnification of the first beam, Includes, The step of detecting the propagated light using the at least one wavefront sensor is: The steps include detecting the first beam with the first wavefront sensor among the at least one wavefront sensor, The steps include detecting the second beam with the second wavefront sensor among the at least one wavefront sensor, and Includes, A method wherein the measurement time defined between the end of the movement of the glass substrate before the light propagates through the thickness and the start of the movement of the glass substrate after the light propagated through the target position is detected using the at least one wavefront sensor is about 100 milliseconds or less.

11. A step of projecting light onto a measuring plane of the glass substrate, wherein the measuring plane extends perpendicular to the thickness of the glass substrate and the thickness is defined between a first main surface and a second main surface of the glass substrate. The steps of reflecting the light toward the glass substrate before the light propagates through the thickness, The method according to claim 10, further comprising:

12. The aforementioned light consists of a first pulse, A step of adjusting the detection distance between the first main surface and the at least one wavefront sensor, The steps include projecting a second pulse onto the measurement plane, The steps include: reflecting the second pulse toward the glass substrate and propagating it through the thickness of the glass substrate; The steps of propagating the reflected second pulse toward the first main surface of the glass substrate through the target position on the first main surface of the glass substrate, The steps include detecting the second pulse that has propagated through the target position using at least one wavefront sensor, The steps include generating a second signal with at least one wavefront sensor based on the detected second pulse, and The method according to claim 11, further comprising:

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