Defect inspection system for sample and defect inspection method for sample

Abstract

A defect inspection system for a sample and a defect inspection method for a sample are provided. The defect inspection system for a sample includes an image sensor and a defect inspection device. The image sensor is configured to capture a target image of a sample, wherein the sample includes a flat portion and a curved portion extending from the flat portion in a first direction and having a curvature. The target image includes a first area corresponding to the flat portion of the sample and a second area corresponding to the curved portion of the sample. The defect inspection device is configured to determine a defect of the sample based on the target image. The defect inspection device includes an image editor configured to enlarge the width of the second area along the first direction according to the resizing ratio.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2018-0138795, filed on November 13, 2018, which is hereby incorporated by reference in its entirety. Technical Field

[0002] The present disclosure relates to a defect inspection system for a sample and a method of inspecting a sample for defects. Background Art

[0003] The display device may be used as a display for mobile devices such as smart phones, digital cameras, video cameras, mobile terminals, laptop computers, and tablet personal computers, or may be applied to electrical and electronic products such as televisions. By considering the influence on user convenience such as user's grip and ease of portability, the display device may have a constant curvature in its edge region (or periphery), and may also provide improved aesthetics. Therefore, the edge region (or periphery region) of the cover glass of the display device also has a constant curvature.

[0004] The cover glass is easily recognized by a user who uses the display device. A defect in the cover glass is one of the defects in the display device that is most easily discovered by the user.

[0005] Defects in the cover glass are detected by an automatic defect inspection system, and there is a method of analyzing the defects using an image obtained by photographing the cover glass.

[0006] The Background section of the specification includes information intended to provide context for example embodiments, and the information in this Background section does not necessarily constitute prior art. Summary of the invention

[0007] Embodiments of the present disclosure provide a defect inspection system and a defect inspection method capable of detecting defects in a sample such as a cover glass.

[0008] The present disclosure provides a defect inspection system and a defect inspection method capable of easily detecting a defect in a bent portion of a sample through one photographing operation (or image capturing operation).

[0009] An embodiment of the present disclosure provides a defect inspection system for a sample, the defect inspection system includes an image sensor and a defect inspection device. The image sensor is configured to capture a target image of the sample. The sample includes a flat portion and a curved portion extending from the flat portion along a first direction and having a curvature. The target image includes a first area corresponding to the flat portion of the sample and a second area corresponding to the curved portion of the sample. The defect inspection device is configured to determine a defect of the sample based on the target image. The defect inspection device includes an image editor configured to enlarge the width of the second area along the first direction according to a resizing ratio.

[0010] The image editor may be configured to separate the first region from the second region, generate a resized region by enlarging a width of the second region, and combine the first region with the resized region to generate the inspection image.

[0011] The defect inspection apparatus may further include a defect detector configured to detect a defect area from the inspection image and a defect identifier configured to compare a size of the defect area with a reference range to determine whether the sample is normal.

[0012] The defect detector may be configured to divide the inspection image into a plurality of regions based on a difference in information between pixels adjacent to each other in the inspection image, and select a defect region from the plurality of regions.

[0013] The defect identifier may be configured to determine that the sample is abnormal when the size of the defect region is greater than a reference range.

[0014] The resizing ratio may be determined based on an angle between a third direction substantially orthogonal to the flat portion and a fourth direction substantially orthogonal to a tangent plane of the curved portion. The resizing ratio may be a secant value of the angle.

[0015] The resizing ratio may include a first ratio and a second ratio, the first ratio being determined based on a first angle between a third direction substantially orthogonal to the flat portion and a fourth direction substantially orthogonal to a first tangent plane at a first point of the curved portion, and the second ratio being determined based on a second angle between the third direction and a fifth direction substantially orthogonal to a second tangent plane at a second point of the curved portion. The image editor may enlarge the width of the second region by the first ratio to generate the first inspection image, and enlarge the width of the second region by the second ratio to generate the second inspection image.

[0016] The defect inspection device may also include a defect detector and a defect identifier, the defect detector is configured to detect a first defect area from a first inspection image and a second defect area from a second inspection image, and the defect identifier is configured to determine that the sample is abnormal when the size of the first defect area is greater than a reference range or when the size of the second defect area is greater than a reference range.

[0017] The curved portion may include a first portion extending from the flat portion in a first direction and a second portion extending from the flat portion in a second direction, the second direction intersecting the first direction, and the second region may include a first curved region corresponding to the first portion and a second curved region corresponding to the second portion. The image editor may enlarge a width of the first curved region corresponding to the first direction and may enlarge a width of the second curved region corresponding to the second direction.

[0018] The curved portion may further include a third portion extending from the first portion in the second direction and extending from the second portion in the first direction. The second region may further include a third curved region corresponding to the third portion. The image editor may enlarge a width of the third curved region corresponding to the first direction and a width of the third curved region corresponding to the second direction.

[0019] An embodiment of the present disclosure provides a method for inspecting defects of a sample. The method includes capturing a target image of the sample. The sample includes a flat portion and a curved portion extending from the flat portion along a first direction and having a curvature relative to a second direction intersecting the first direction. The method also includes extracting a first area corresponding to the flat portion and a second area corresponding to the curved portion from the target image, enlarging the width of the second area corresponding to the first direction to generate an inspection image, and determining whether the sample is normal based on the inspection image.

[0020] The generating step of the inspection image may include enlarging a width of the second region at a resizing ratio to generate a resized region, and combining the first region with the resized region.

[0021] The resizing ratio may be a secant value of an angle between a third direction substantially orthogonal to the flat portion and a fourth direction substantially orthogonal to a tangent plane of the curved portion.

[0022] The step of determining whether the sample is normal may include detecting a defective area from the inspection image, and comparing a size of the defective area with a reference range to determine a defect of the sample.

[0023] When at least a portion of the defective region exists in the second region, the defective region in the second region may be enlarged along the first direction in the generating of the inspection image.

[0024] The step of generating an inspection image may include: enlarging the width of the second area according to a first ratio to generate a first resized area, combining the first area with the first resized area to generate a first inspection image, enlarging the width of the second area according to a second ratio different from the first ratio to generate a second resized area, and combining the first area with the second resized area to generate a second inspection image.

[0025] The step of determining whether the sample is normal may include: detecting a first defect area from a first inspection image, detecting a second defect area from a second inspection image, and determining that the sample is abnormal when the size of the first defect area is greater than a reference range or when the size of the second defect area is greater than a reference range.

[0026] The step of determining whether the sample is normal may include: detecting a first defect area from a first inspection image, detecting a second defect area from a second inspection image, and determining that the sample is normal when the size of the first defect area is smaller than a reference range and the size of the second defect area is smaller than the reference range.

[0027] The sample may include a cover glass on a display panel.

[0028] According to the above, a defect can be determined by considering the size of the defect distorted when photographing a curved portion of a sample (e.g., when capturing an image of the sample). Therefore, the reliability of defect detection for the sample can be improved. In addition, a defect inspection operation can be performed through one photographing operation (or image capturing operation), and a calculation operation for compensating for the distortion of the curved portion can be simplified, thereby quickly determining whether the sample includes a defect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other aspects of the present disclosure will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0030] Figure 1 is a schematic diagram showing a defect inspection system for a sample according to an example embodiment of the present disclosure;

[0031] Figure 2 It is shown Figure 1 A block diagram of a defect inspection device;

[0032] Figure 3 is a flow chart showing a method of inspecting a sample for defects;

[0033] Figure 4 is a perspective view showing a sample to be inspected for defects according to an embodiment;

[0034] Figure 5 It is shown Figure 4 A cross-sectional view of a curved portion of a sample;

[0035] Figure 6 is shown by capturing Figure 4 A plan view of a target image obtained by using an image of the sample;

[0036] Figure 7 It is shown based on Figure 6 A plan view of an inspection image generated from a target image;

[0037] Figure 8 It is shown Figure 4 A cross-sectional view of a curved portion of a sample;

[0038] Fig. 9 Is shown to check Figure 8 A flow chart of a method for detecting defects in a sample;

[0039] Fig.10 is a perspective view showing a sample to be inspected for defects according to an embodiment;

[0040] Fig.11 It is shown based on Fig.10 a plan view of an inspection image generated from a target image of the sample; and

[0041] Fig.12 is a perspective view showing a display device to which the sample is applied. DETAILED DESCRIPTION

[0042] The present disclosure may be modified and implemented in many different forms, so specific embodiments are illustrated in the drawings and described herein. However, the present disclosure should not be limited to a specific disclosure form, and should be interpreted as including all modifications, equivalents or substitutes included in the spirit and scope of the present disclosure. On the contrary, these embodiments are provided as examples so that the present disclosure will be detailed and complete, and will fully convey the aspects and features of the present invention to those skilled in the art. Therefore, the processing, elements and techniques that are not necessary for a complete understanding of the aspects and features of the present disclosure by those of ordinary skill in the art may not be described. Unless otherwise noted, the same figure numerals represent the same elements throughout the drawings and written descriptions, and therefore, their descriptions may not be repeated. In the drawings, the relative sizes of elements, layers and regions may be exaggerated for clarity.

[0043] It will be understood that, although the terms first, second, etc. can be used to describe various elements, components, regions, layers and / or parts here, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish an element, component, region, layer or part from another region, layer or part. Therefore, without departing from the teaching of the present disclosure, the first element, component, region, layer or part discussed below may be referred to as the second element, component, region, layer or part. As used herein, unless the context clearly indicates otherwise, the singular form "one (kind / person)" and "the (described)" are also intended to include plural forms.

[0044] It will be understood that when an element or layer is referred to as being “on,” “connected to” or “coupled to” another element or layer, the element or layer may be directly on, directly connected to or directly coupled to the other element or layer, or one or more intervening elements or layers may be present.

[0045] It will also be understood that the terms "comprises" and "includes" and variations thereof, when used in this specification, indicate the presence of stated features, integers, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. When a statement such as "at least one of..." follows a list of elements, the statement modifies the entire list of elements rather than modifying a single element in the list.

[0046] As used herein, the terms "substantially", "approximately" and similar terms are used as approximate terms rather than as terms of degree, and are intended to explain the inherent deviations of measurements and calculations that will be recognized by those of ordinary skill in the art. In addition, when describing embodiments of the present invention, "may (may)" is used to represent "one or more embodiments of the present invention". In addition, when describing embodiments of the present invention, optional language (such as "or") is used to represent "one or more embodiments of the present invention" for each corresponding listed item. As used herein, the term "use" and variations thereof may be considered synonymous with the term "utilize" and variations thereof, respectively. In addition, the term "exemplary" is intended to represent an example or illustration.

[0047] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. It will also be understood that, unless expressly defined herein, terms (such as those defined in common dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and / or this specification, and should not be interpreted in an idealized or overly formal sense.

[0048] Hereinafter, embodiments of the present disclosure are explained with reference to the accompanying drawings.

[0049] Figure 1 is a schematic diagram showing a defect inspection system 100 for a sample WD according to an example embodiment of the present disclosure. The defect inspection system 100 is configured to detect a defect of the sample WD (or in or on the sample WD) and is configured to determine whether the sample WD is normal or abnormal. For example, the defect may be a scratch. Figure 1 , the defect inspection system 100 includes an image sensor 110 , a defect inspection device 120 and a display device 160 .

[0050] In the present exemplary embodiment, the sample WD may be a cover member (e.g., a cover) that protects the display panel when manufacturing the display device 160. The cover member may prevent the display panel from being damaged by factors such as fingerprints, scratches, moisture, dust, or external influences caused by touch, or may reduce the possibility of damage to the display panel. For example, the sample WD may include a transparent or translucent glass material, however, the present disclosure should not be limited thereto or thereby. For example, the sample WD may include a polymer material such as polyimide (PI), polycarbonate (PC), polyethersulfone (PES), or polyethylene terephthalate (PET).

[0051] The sample WD may include a flat portion and a curved portion. The curved portion extends from the flat portion. The curved portion may have a curvature and may be curved. The curved portion may define an edge region (eg, periphery) of the sample WD. Figure 1 The side surface of sample WD is shown.

[0052] The image sensor 110 captures an image of the sample WD (e.g., photographs the sample WD). The image sensor 110 may capture an image of the sample WD corresponding to the display surface when the sample WD is on (or disposed on) the display panel (e.g., photographs the front surface of the sample WD). The image sensor 110 may obtain (or capture) a target image, for example, by photographing the sample WD. The target image may include an image corresponding to a flat portion of the sample WD and an image corresponding to a curved portion of the sample WD.

[0053] The image sensor 110 includes a plurality of image pixels arranged in an array. Each of the image pixels senses light of a frequency band (e.g., a specific frequency band). The specific frequency band may be a visible light band, but it should not be limited thereto or thereby. The sensed light may be converted into an analog electrical signal, and the analog electrical signal may be converted into a digital signal. A target image corresponding to the image pixel may be generated based on the digital signal. The target image may include pixel information corresponding to the image pixels, respectively.

[0054] The defect inspection apparatus 120 is configured to determine the presence of defects of the sample WD based on the target image. For example, the defect inspection apparatus 120 receives the target image from the image sensor 110. The defect inspection apparatus 120 may include an image editor 130, a defect detector 140, and a defect identifier 150.

[0055] The image editor 130 adjusts the size of the received target image to generate an inspection image. When the image sensor 110 captures an image of the sample WD (e.g., photographs the sample WD), the image of the flat portion has a shape similar to the actual flat portion (e.g., has a shape similar to the shape of the flat portion of the sample WD), but because the captured (or photographed) image is spatially two-dimensional, the image of the curved portion is distorted and has a shape different from the actual curved portion (e.g., has a shape different from the shape of the curved portion of the sample WD). A defect in the curved portion of the image may appear smaller than the actual size of the defect. The image editor 130 corrects the image corresponding to the curved portion, thereby improving the reliability of defect detection.

[0056] The image editor 130 enlarges the image corresponding to the curved portion of the target image. When the user views the sample WD in a direction different from the photographing direction of the image sensor 110 (e.g., a direction substantially orthogonal or perpendicular to the tangent plane of the curved portion), the user may perceive that the size of the defect is larger than the size of the defect appearing in the target image. For example, the image editor 130 may enlarge the image corresponding to the curved portion at a specific ratio by considering the size of the defect viewed in another direction.

[0057] For example, the image editor 130 may not enlarge the image in the same manner as the curved portion is stretched. Because the user's eyes can recognize the three-dimensional space as a two-dimensional space in a similar manner to the image sensor 110, it is not necessary to enlarge the image (such as to stretch the curved portion) in terms of visibility of the defect. Therefore, the image editor 130 may uniformly enlarge the image at a ratio (or at a predetermined ratio or at a ratio of a predetermined number). For example, by considering the curvature, the amount of calculation can be reduced compared to the amount by which the image is enlarged (such as to stretch the curved portion).

[0058] The image editor 130 may detect and separate an image corresponding to a flat portion and an image corresponding to a curved portion to enlarge the image corresponding to the curved portion. For example, assuming that the size and position of the sample WD are not changed and a specific area of ​​the target image is an image corresponding to the curved portion, the image editor 130 may detect and separate the image corresponding to the curved portion. For example, the image editor 130 may detect and separate the image corresponding to the curved portion based on the difference in brightness, color, and / or saturation of the image between the flat portion and the curved portion due to the depth difference between the flat portion and the curved portion. Subsequently, the image editor 130 may enlarge the image corresponding to the curved portion and may combine the enlarged image with the image corresponding to the flat portion, thereby generating an inspection image.

[0059] The defect detector 140 analyzes the inspection image generated by the image editor 130 and detects a defective area of ​​the sample WD in which a defect exists. For example, the defect detector 140 may detect the defective area by a connected pixel detection method (BLOB method). For example, the defect detector 140 may divide the inspection image into a plurality of areas based on the difference of mutually adjacent pixel information among the pixel information included in the inspection image. The pixel information may be information obtained by digitizing brightness, color, and / or saturation. The defect detector 140 may group areas having the same digitized information and having a difference less than a reference value from each other into one group.

[0060] The defect detector 140 may select at least one defective region among the grouped regions. The defect may be different in properties such as brightness, color, and / or saturation compared to the surrounding regions, and the defective region may be determined based on the difference. For example, pixel information or patterns according to the type of defect may be recorded in advance, and the defect detector 140 may detect at least one defective region among the regions based on the record.

[0061] The defect identifier 150 may determine whether the sample WD includes a defect based on the defect area detected by the defect detector 140. The defect identifier 150 compares the size of the defect area with the reference range to determine whether the sample WD is normal or abnormal. In this example embodiment, the reference range may be set based on the minimum defect size that allows the sample WD to be applied to the display device. When the size of the defect area is larger than the reference range (or equal to or larger than the reference range), the sample WD may be determined to be abnormal. When the size of the defect area is equal to or smaller than the reference range (or smaller than the reference range), the sample WD may be determined to be normal.

[0062] The display device 160 may display an image that allows a user of the defect inspection system 100 to recognize the inspection result. The image may be a target image generated by the image sensor 110 or an inspection image generated by the defect inspection device 120, however, the image should not be limited thereto or thereby. For example, the display device 160 may display a defective area or may display whether the sample WD is normal.

[0063] Figure 2 It is shown Figure 1 A block diagram of a defect inspection device 120 is shown. Figure 2 The defect inspection device 120 shown in FIG. Figure 1 The defect inspection device 120 corresponds to and has a configuration for determining a defect of the sample WD based on the target image obtained by the image sensor 110. However, the configuration of the defect inspection device 120 should not be limited thereto or thereby. Figure 2The defect inspection apparatus 120 includes a camera interface 121 , a processor 122 , a memory 123 , a storage device 124 , a display interface 125 , a network interface 126 and a bus 127 .

[0064] Camera interface 121 from Figure 1 The image sensor 110 receives the target image. The defect inspection apparatus 120 communicates with the image sensor 110 via the camera interface 121. For example, the camera interface 121 may communicate serially with the image sensor 110. For example, a deserializer may be implemented in the camera interface 121, and a serializer may be implemented in the image sensor 110.

[0065] The processor 122 may function as a central processing unit of the defect inspection device 120. The processor 122 may perform control operations and calculation operations used (or required) for adjusting the size of the target image, generating an inspection image, detecting a defective area, and determining the defects of the sample WD. For example, the camera interface 121 may receive the target image in response to the control of the processor 122. According to the control of the processor 122, an image corresponding to the curved portion may be extracted from the target image and the size of the image corresponding to the curved portion may be adjusted. According to the control of the processor 122, a defective area may be detected and the defects of the sample WD may be determined. The processor 122 may operate using the calculation space of the memory 123, and may read out files for running the operating system and execution files of applications from the storage device 124.

[0066] The memory 123 may store data and processor codes that are processed by the processor 122 (or to be processed by the processor 122). For example, the memory 123 may store a target image provided from the camera interface 121, information for generating an inspection image, information for detecting a defective area, and information for determining defects of the sample WD. The memory 123 may be used as a main memory device of the defect inspection device 120. For example, the memory 123 may include a dynamic RAM (DRAM), a static RAM (SRAM), a phase change RAM (PRAM), a magnetic RAM (MRAM), a ferroelectric RAM (FeRAM), or a resistive RAM (RRAM).

[0067] The memory 123 may include an image editor 130, a defect detector 140, and a defect identifier 150. The image editor 130, the defect detector 140, and the defect identifier 150 are connected to the image editor 130. Figure 1The image editor 130, the defect detector 140, and the defect identifier 150 correspond to each other. The image editor 130, the defect detector 140, and the defect identifier 150 may be part of the computing space of the memory 123. For example, the image editor 130, the defect detector 140, and the defect identifier 150 may be implemented by firmware or software. For example, the firmware may be stored in the storage device 124 and the firmware may be loaded into the memory 123 when the firmware is executed. The processor 122 may execute the firmware loaded into the memory 123.

[0068] The image editor 130 may be operated under the control of the processor 122 to extract an image corresponding to the bent portion in the target image and resize it, so that the image editor 130 may generate an inspection image. The defect detector 140 may be operated under the control of the processor 122 to detect at least one defect area in the inspection image. The defect identifier 150 may be operated under the control of the processor 122 to determine whether the sample WD is normal or abnormal based on the size of the defect area.

[0069] In some embodiments, the image editor 130, the defect detector 140, and the defect identifier 150 may be implemented as separate hardware components. For example, the image editor 130, the defect detector 140, and the defect identifier 150 may be implemented by a dedicated logic circuit such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

[0070] The storage device 124 may store data generated by an operating system or an application for long-term storage, files for driving the operating system, or execution files of applications. For example, the storage device 124 may store files for executing the image editor 130, the defect detector 140, and the defect identifier 150. The storage device 124 may be used as an auxiliary memory device of the defect inspection device 120. For example, the storage device 124 may include a flash memory, a phase change RAM (PRAM), a magnetic RAM (MRAM), a ferroelectric RAM (FeRAM), or a resistive RAM (RRAM).

[0071] The display interface 125 can be connected to Figure 1 As an example, the display interface 125 may communicate serially with the display device 160. For example, a serializer may be implemented in the display interface 125, and a deserializer may be implemented in the display device 160.

[0072] The network interface 126 may communicate with an external electronic device. As an example, the network interface 126 may be based on at least one wireless communication method such as long term evolution (LTE), code division multiple access (CDMA), WiFi, or radio frequency identification (RFID) or a wired communication method such as a universal serial bus (USB), a serial AT attachment (SATA), a serial peripheral interface (SPI), and / or an inter-integrated circuit (I 2 C)) Perform communication.

[0073] The bus 127 may provide a communication path between the components of the defect inspection apparatus 120. The camera interface 121, the processor 122, the memory 123, the storage device 124, the display interface 125, and the network interface 126 may exchange data with each other via the bus 127. The bus 127 may support various types of communication formats used in the defect inspection apparatus 120.

[0074] Figure 3 is a flow chart showing a defect inspection method for a sample. Figure 3 Each operation can be performed by Figure 1 Defect inspection system 100 or Figure 2 The defect inspection device 120 is executed and can be Figure 2 For ease of explanation, refer to Figure 1 Description of the reference numerals Figure 3 Defect inspection method.

[0075] In operation S110, the image sensor 110 captures an image of the sample WD (e.g., photographs the sample WD) to obtain a target image. The target image is provided to the defect inspection device 120. The target image includes a first area corresponding to a flat portion of the sample WD and a second area corresponding to a curved portion of the sample WD.

[0076] In operation S120, the defect inspection apparatus 120 extracts a first region and a second region from the target image. The first region and the second region may be extracted by the image editor 130. The image editor 130 may separate the first region and the second region.

[0077] In operation S130, the defect inspection device 120 may resize the second area. The size of the second area may be resized by the image editor 130. The image editor 130 may enlarge the second area according to the resizing ratio to generate a resized area (or resized area). The resizing ratio may be set based on an angle between a direction substantially orthogonal (or perpendicular) to the flat portion and a direction substantially orthogonal (or perpendicular) to a tangent plane (e.g., an arbitrary tangent plane) of the curved portion. The image editor 130 combines the first area with the resized area to generate an inspection image.

[0078] In operation S140, the defect inspection apparatus 120 analyzes the inspection image to detect at least one defect region. The defect region may be detected by the defect detector 140. For example, the defect detector 140 may detect the defect region using a connected pixel detection method.

[0079] In operation S150, the defect inspection device 120 may determine the defect of the sample WD based on the size of the defect area. The defect of the sample WD may be determined by the defect identifier 150. For example, the defect identifier 150 compares the size of the defect area with a reference range to determine whether the sample WD is normal or abnormal.

[0080] Figure 4 is a perspective view showing a sample WD1 to be inspected for defects. Figure 1 The sample WD1 may be a cover member (eg, a cover) for protecting the display panel, for example, a cover glass. Figure 4 , the sample WD1 includes a flat portion FA, a first curved portion CA1, and a second curved portion CA2.

[0081] Hereinafter, for convenience of explanation, a first direction DR1, a second direction DR2, and a third direction DR3 are defined. The first direction DR1 corresponds to a direction in which the first curved portion CA1, the flat portion FA, and the second curved portion CA2 are arranged. The second direction DR2 may correspond to a direction in which each of the first curved portion CA1, the flat portion FA, and the second curved portion CA2 extends and may be substantially orthogonal (or perpendicular) to the first direction DR1. The third direction DR3 corresponds to a photographing direction of the image sensor 110, wherein the photographing direction is substantially orthogonal (or perpendicular) to the first direction DR1 and the second direction DR2.

[0082] The surface of the flat portion FA may be substantially parallel to a plane (or surface) defined by the first direction DR1 and the second direction DR2 and may be substantially orthogonal (or perpendicular) to the third direction DR3. The first curved portion CA1 and the second curved portion CA2 extend from the flat portion FA along the first direction DR1. The surfaces of the first curved portion CA1 and the second curved portion CA2 connected to the surface of the flat portion FA have a curvature with respect to the second direction DR2. The first curved portion CA1 and the second curved portion CA2 may have the same curvature, however, they should not be limited thereto or thereby. The first curved portion CA1 and the second curved portion CA2 may be edge regions of the sample WD1 (or peripheral regions of the sample WD1).

[0083] Figure 1The image sensor 110 captures an image of the sample WD1 along the third direction DR3 (e.g., photographs the sample WD1). When the defect exists in the flat portion FA, the defect is not distorted in the target image. When the defect exists in the first curved portion CA1 and the second curved portion CA2, the defect is distorted in the target image. For example, the defect appearing on the target image may be smaller than the actual size of the defect.

[0084] Figure 5 It is shown Figure 4 A cross-sectional view of a first curved portion CA1 of sample WD1. Figure 5 The first curved portion CA1 shown in FIG. Figure 4 corresponds to the first curved portion CA1. Figure 5 The first curved portion CA1 shown in FIG. Figure 4 The second direction DR2 is obtained when viewing the first curved portion CA1.

[0085] Reference Figure 5 , the first curved portion CA1 has a first length L1 along the first direction DR1. The first curved portion CA1 is recognized (perceived) as the first length L1 along the third direction. Figure 1 The image sensor 110 captures an image of the first curved portion CA1 along the third direction DR3 (e.g., photographs the first curved portion CA1), so the curve of the curved portion is photographed (or captured) to have the first length L1. Therefore, when a defect exists on the curve of the first curved portion CA1, the defect is photographed (or captured) with a length smaller than the actual length of the defect.

[0086] When the first curved portion CA1 is viewed in a direction having a difference of the first angle a1 with respect to the third direction DR3 (hereinafter, referred to as a "viewing direction"), the first curved portion CA1 is recognized (perceived) as a second length L2. The second length L2 is greater (or longer) than the first length L1, and a defect on the curve of the first curved portion CA1 may appear larger along the viewing direction than a defect along the third direction DR3. Therefore, when the image of the first curved portion CA1 is not additionally processed, a defect that is not discovered by image capture (or shooting) only along the third direction DR3 may be discovered later.

[0087] Figure 1The defect inspection device 120 may perform a resizing operation to enlarge a first length L1 in a target image to a second length L2, wherein the first length L1 is obtained by capturing an image of the first curved portion CA1 along a third direction DR3 (e.g., photographing the first curved portion CA1), and the second length L2 is obtained by capturing an image of the first curved portion CA1 along a viewing direction (e.g., photographing the first curved portion CA1). As such, a resizing ratio is required that is a ratio of the second length L2 to the first length L1. The resizing ratio is determined based on a first angle a1. The intersection P1 corresponds to a point (e.g., an arbitrary point) on the curve of the first curved portion CA1 and is determined based on the viewing direction. The tangent passing through the intersection P1 is substantially orthogonal (or perpendicular) to the viewing direction, and the first angle a1 is the angle between the viewing direction and the third direction DR3. Therefore, the resizing ratio may be calculated as a secant value sec(a1) of the first angle a1.

[0088] The resizing ratio may be set in advance for the defect inspection device 120. For example, the resizing ratio may be determined by considering a defect occurrence pattern, a location where a large number of defects occur, a manufacturing process, and defect detection efficiency. As an example, when it is determined that the defect inspection efficiency is highest when the intersection point P1 is located in the middle of the curve of the first curved portion CA1, the resizing ratio is approximately sec(45°), that is, approximately the square root of 2.

[0089] Figure 6 is shown by capturing Figure 4 Sample WD1 (or by shooting Figure 4 The plan view of the target image obtained by imaging the sample WD1). Figure 6 , the target image IMG includes a first area AR1, a second area AR2 and a third area AR3. The first area AR1 is Figure 4 The second area AR2 is an image corresponding to the flat part FA. Figure 4 The third area AR3 is an image (bending area) corresponding to the first curved portion CA1. Figure 4 An image (curved area) corresponding to the second curved portion CA2.

[0090] exist Figure 6 In the embodiment, for convenience of explanation, a first direction DR1, a second direction DR2, and a third direction DR3 are defined. The target image IMG is information obtained based on pixels arranged two-dimensionally in the image sensor 110, and the sample WD1 exists in a three-dimensional space. Therefore, Figure 6 The first direction DR1, the second direction DR2 and the third direction DR3 should not be strictly in accordance with Figure 4The first direction DR1, the second direction DR2 and the third direction DR3 are interpreted in the same meaning. However, since the coordinates of the target image IMG correspond to the coordinates of the sample WD1, it will be apparent that Figure 6 The first direction DR1, the second direction DR2 and the third direction DR3 are respectively Figure 4 The first direction DR1, the second direction DR2 and the third direction DR3 correspond to each other.

[0091] The second area AR2 and the third area AR3 correspond to the first curved portion CA1 and the second curved portion CA2, respectively, and therefore, the second area AR2 and the third area AR3 may be (or have) distorted images. Figure 4 The first curved portion CA1 and the second curved portion CA2 have a curvature with respect to the second direction DR2. Therefore, each of the second area AR2 and the third area AR3 may be distorted in the first direction DR1 but may not be distorted in the second direction DR2.

[0092] In this example embodiment, it is assumed that the first defect area df1, the second defect area df2, the third defect area df3, the fourth defect area df4, and the fifth defect area df5 exist in the target image IMG as a result of forming a defect in the sample WD1. Because the first defect area df1 is formed in the first area AR1, the first defect area df1 can be an undistorted image. Because the second defect area df2 is formed in the second area AR2 and extends substantially along the first direction DR1, the second defect area df2 can be an image distorted to be smaller than the actual length of the defect. The third defect area df3 is formed in the second area AR2 and extends substantially along the second direction DR2, so the third defect area df3 can be an image with almost no distortion. The fourth defect area df4 is formed in the third area AR3 and extends in a direction different from the first direction DR1 and the second direction DR2, as a result, the fourth defect area df4 can be an image distorted in the first direction DR1 and undistorted in the second direction DR2. Since the fifth defect area df5 is formed on the first area AR1 and the third area AR3 and extends substantially in the first direction DR1, the fifth defect area df5 may be an image distorted only in an area corresponding to the third area AR3.

[0093] Figure 7 It is shown based on Figure 6 The target image is generated as a plan view of the inspection image. Figure 7, the inspection image IMGa includes the first area AR1, the first resized area RA1, and the second resized area RA2. As described above, the inspection image IMGa is an image obtained by combining the first area AR1, the first resized area RA1, and the second resized area RA2, however, for convenience of explanation, the first area AR1, the first resized area RA1, and the second resized area RA2 are shown after being separated from each other.

[0094] First, you can Figure 6 The first area AR1, the second area AR2 and the third area AR3 are extracted from the target image IMG and the first area AR1, the second area AR2 and the third area AR3 are separated from each other. Subsequently, the second area AR2 and the third area AR3 may be enlarged along the first direction DR1 according to the resizing ratio. As a result, a first resized area RA1 and a second resized area RA2 are generated. For example, the second area AR2 has a first width W1 along the first direction DR1, and the first resized area RA1 has a second width W2 along the first direction DR1. The second width W2 is greater than the first width W1. The resizing ratio may be a ratio of the second width W2 to the first width W1.

[0095] The first defect region df1 may be maintained as Figure 6 The first defect area df1 of the target image IMG is the same as the first defect area df1 of the target image IMG. The second defect area df2 is enlarged along the first direction DR1 by enlarging the second area AR2. The third defect area df3 extends along the second direction DR2, so although the second area AR2 is enlarged, the size of the third defect area df3 is almost unchanged. As the third area AR3 is enlarged, the fourth defect area df4 is enlarged along the first direction DR1 but not along the second direction DR2. The portion of the fifth defect area df5 formed in the first area AR1 is not enlarged, and the portion of the fifth defect area df5 formed in the third area AR3 is enlarged.

[0096] The inspection image IMGa is used to detect defects of the sample WD1. A first defect region df1, a second defect region df2, a third defect region df3, a fourth defect region df4, and a fifth defect region df5 are detected from the inspection image IMGa, and each of the first defect region df1, the second defect region df2, the third defect region df3, the fourth defect region df4, and the fifth defect region df5 can be compared with a reference range. The first defect region df1, the second defect region df2, the third defect region df3, the fourth defect region df4, and the fifth defect region df5 compared with the reference range are images on which a resizing operation has been performed as described above.

[0097] Figure 8 It is shown Figure 4 sectional view of the first curved portion CA1. Figure 8 The curved portion shown in Figure 4 and Figure 5 The first curved portion CA1 corresponds to Figure 8 , the first curved portion CA1 has a first length L1 along the first direction DR1. When viewed along the third direction DR3, the first curved portion CA1 is recognized to have the first length L1.

[0098] According to an embodiment, a plurality of resizing ratios for defect inspection of sample WD1 may be provided. For example, the first resizing ratio may be determined based on the difference of the first viewing direction having a first angle aa relative to the third direction DR3 and may be the secant value sec(aa) of the first angle. For example, the second resizing ratio may be determined based on the difference of the second viewing direction having a second angle ab relative to the third direction DR3 and may be the secant value sec(ab) of the second angle. The first viewing direction may be a direction substantially orthogonal (or perpendicular) to a tangent of the first point Pa, and the second viewing direction may be a direction substantially orthogonal (or perpendicular) to a tangent of the second point Pb. The first curved portion CA1 may have a first viewing length La in a direction substantially orthogonal (or perpendicular) to the first viewing direction and may have a second viewing length Lb in a direction substantially orthogonal (or perpendicular) to the second viewing direction.

[0099] Fig. 9 It is shown for Figure 4 and Figure 8 Flow chart of the defect inspection method of sample WD1. Figure 1 Defect inspection system 100 or Figure 2 The defect inspection device 120 performs Fig. 9 Each operation of Fig. 9 , describes a defect inspection method for detecting defects of a sample using multiple resizing ratios. For ease of explanation, refer to Figure 8 Description of the reference numerals Fig. 9 The defect inspection method shown in FIG.

[0100] In operation S210, a target image is obtained, and this operation is similar to Figure 3 In operation S220, a first region corresponding to a flat portion and a second region corresponding to a curved portion are extracted from the target image, and this operation corresponds to operation S110. Figure 3 Corresponding to operation S120.

[0101] In operation S230, based on the first ratio ( Figure 8The second region is resized according to the first resizing ratio (the first resizing ratio of the first region). The second region resized according to the first resizing ratio is combined with the first region, and a first inspection image is generated. In addition, in operation S235, based on the second resizing ratio ( Figure 8 The second region is resized according to a second resizing ratio of the first ratio to the second ratio. The first ratio is different from the second ratio. The second region resized according to the second ratio is combined with the first region, and a second inspection image is generated.

[0102] In operation S240, a defective area is detected from the first inspection image. In addition, in operation S245, a defective area is detected from the second inspection image. The method of detecting a defective area is similar to Figure 3 The method corresponds to operation S140.

[0103] In operation S250, the defective area detected in operation S240 and operation S245 is compared with a reference range. When the defective area is greater than the reference range (or equal to or greater than the reference range), the sample is determined to be abnormal in operation S252. When at least one of the size of the defective area detected from the first inspection image and the size of the defective area detected from the second inspection image is greater than the reference range, the sample is determined to be abnormal.

[0104] When the defect range is equal to or less than the reference range (or less than the reference range), the sample is determined to be normal in operation S254. When the size of the defect area detected from the first inspection image and the size of the defect area detected from the second inspection image are equal to or less than the reference range, the sample is determined to be normal.

[0105] The first resizing ratio and the second resizing ratio different from each other are applied to the target image in parallel, so the image correction reliability of the curved portion can be improved. As a result, the defect detection reliability of the sample can be improved.

[0106] Fig.10 is a perspective view showing a sample WD2 to be inspected for defects. Figure 1 The sample WD2 may be a cover member (eg, a cover) for protecting the display panel, and may be, for example, a cover glass. Fig.10 , the sample WD2 includes the flat portion FA and first, second, third, fourth, fifth, sixth, seventh, and eighth curved portions CA1, CA2, CA3, CA4, CA5, CA6, CA7, and CA8.

[0107] The sample WD2 may include peripheral (or edge) regions disposed at four sides adjacent to the flat portion FA, wherein each of the peripheral (or edge) regions has a curvature. The first curved portion CA1 and the second curved portion CA2 extend from the flat portion FA in the first direction DR1 and have a curvature with respect to the second direction DR2. The third curved portion CA3 and the fourth curved portion CA4 extend from the flat portion FA in the second direction DR2 and have a curvature with respect to the first direction DR1.

[0108] The fifth curved portion CA5 extends from the first curved portion CA1 in the second direction DR2 and extends from the third curved portion CA3 in the first direction DR1. The sixth curved portion CA6 extends from the first curved portion CA1 in the second direction DR2 and extends from the fourth curved portion CA4 in the first direction DR1. The seventh curved portion CA7 extends from the second curved portion CA2 in the second direction DR2 and extends from the third curved portion CA3 in the first direction DR1. The eighth curved portion CA8 extends from the second curved portion CA2 in the second direction DR2 and extends from the fourth curved portion CA4 in the first direction DR1. The fifth curved portion CA5, the sixth curved portion CA6, the seventh curved portion CA7 and the eighth curved portion CA8 have a curvature with respect to a direction intersecting the first direction DR1 and the second direction DR2 and substantially orthogonal (or perpendicular) to the third direction DR3.

[0109] Fig.11 It is shown based on Fig.10 The target image of the sample generates a plan view of the inspection image IMGb. Fig.10 The target image obtained by the sample WD2 includes a first area AR1, a second area AR2, a third area AR3, a fourth area AR4, a fifth area AR5, a sixth area AR6, a seventh area AR7, an eighth area AR8 and a ninth area AR9. The first area AR1 is Fig.10 The second area AR2, the third area AR3, the fourth area AR4, the fifth area AR5, the sixth area AR6, the seventh area AR7, the eighth area AR8 and the ninth area AR9 are respectively Fig.10 The images corresponding to the first curved portion CA1, the second curved portion CA2, the third curved portion CA3, the fourth curved portion CA4, the fifth curved portion CA5, the sixth curved portion CA6, the seventh curved portion CA7 and the eighth curved portion CA8.

[0110] Reference Fig.11, an inspection image IMGb is generated by adjusting the size of the second area AR2, the third area AR3, the fourth area AR4, the fifth area AR5, the sixth area AR6, the seventh area AR7, the eighth area AR8 and the ninth area AR9 of the target image. The inspection image IMGb includes the first area AR1 and the first resized area RA1, the second resized area RA2, the third resized area RA3, the fourth resized area RA4, the fifth resized area RA5, the sixth resized area RA6, the seventh resized area RA7 and the eighth resized area RA8. For the resizing operation, the first area AR1, the second area AR2, the third area AR3, the fourth area AR4, the fifth area AR5, the sixth area AR6, the seventh area AR7, the eighth area AR8 and the ninth area AR9 can be separated from each other. Subsequently, the second area AR2, the third area AR3, the fourth area AR4, the fifth area AR5, the sixth area AR6, the seventh area AR7, the eighth area AR8 and the ninth area AR9 can be resized and combined to the first area AR1 to generate the inspection image IMGb.

[0111] The second area AR2 and the third area AR3 may be enlarged along the first direction DR1 at a first resizing ratio. As a result, a first resized area RA1 and a second resized area RA2 are generated. For example, the second area AR2 has a first width W1 along the first direction DR1, and the first resized area RA1 has a second width W2 along the first direction DR1. The first resizing ratio may be a ratio of the second width W2 to the first width W1.

[0112] The fourth area AR4 and the fifth area AR5 may be enlarged along the second direction DR2 at a second resizing ratio. As a result, a third resized area RA3 and a fourth resized area RA4 are generated. For example, the fifth area AR5 has a third width W3 along the second direction DR2, and the fourth resized area RA4 has a fourth width W4 along the second direction DR2. The second resizing ratio may be a ratio of the fourth width W4 to the third width W3.

[0113] The sixth area AR6, the seventh area AR7, the eighth area AR8 and the ninth area AR9 may be enlarged at a first resizing ratio along the first direction DR1 and at a second resizing ratio along the second direction DR2. As a result, a fifth resized area RA5, a sixth resized area RA6, a seventh resized area RA7 and an eighth resized area RA8 are generated.

[0114] Assume that there are first defective area df1, second defective area df2, third defective area df3, and fourth defective area df4 samples in the target image as a result of forming defects in the sample WD2. Since the first defective area df1 is formed in the first area AR1 corresponding to the flat portion FA, the first defective area df1 is not enlarged despite the resizing operation. The second defective area df2 is formed in the second area AR2, so the second defective area df2 is enlarged along the first direction DR1 according to the first resizing ratio. The third defective area df3 is formed in the fourth area AR4, and as a result, the third defective area df3 is enlarged along the second direction DR2 according to the second resizing ratio. Since the fourth defective area df4 is formed in the sixth area AR6, the fourth defective area df4 is enlarged along the first direction DR1 according to the first resizing ratio and enlarged along the second direction DR2 according to the second resizing ratio.

[0115] A first defect area df1, a second defect area df2, a third defect area df3, and a fourth defect area df4 may be detected from the inspection image IMGb, and each of the first defect area df1, the second defect area df2, the third defect area df3, and the fourth defect area df4 may be compared with a reference range. The first defect area df1, the second defect area df2, the third defect area df3, and the fourth defect area df4 compared with the reference range are images on which the resizing operation is performed as described above.

[0116] Fig.12 is a perspective view showing a display device 1000 to which the sample is applied. Fig.12 , the display device 1000 includes a cover (eg, cover glass) 1100 and a display panel 1200. The cover glass 1100 is similar to the display panel 1200. Figures 1 to 11 The samples described correspond to WD / WD1 / WD2.

[0117] The cover glass 1100 includes a flat portion FA, a first curved portion CA1, and a second curved portion CA2. The first curved portion CA1 and the second curved portion CA2 may extend from the flat portion FA in a first direction DR1. Each of the flat portion FA, the first curved portion CA1, and the second curved portion CA2 may extend in a second direction DR2. The cover glass 1100 is disposed on the display panel 1200 in a third direction DR3. The cover glass 1100 protects the display panel 1200 from external factors such as a touch operation, a sharp object, moisture, and dust.

[0118] The display panel 1200 is configured to display an image. The display panel 1200 may be a curved display panel maintained in a curved state corresponding to the cover glass 1100, however, it should not be limited thereto or thereby. For example, the display panel 1200 may display an image through an area corresponding to the flat portion FA, and a bezel area may be defined in an area corresponding to the first curved portion CA1 and the second curved portion CA2.

[0119] The display panel 1200 may be one of various display panels such as a liquid crystal display panel, an organic light emitting display panel, an electrophoretic display panel, and an electrowetting display panel.

[0120] Although example embodiments of the present disclosure have been described, it will be understood that the present disclosure should not be limited to these example embodiments, but various changes and modifications may be made by one of ordinary skill in the art within the spirit and scope of the present disclosure as claimed below.

[0121] Thus, the disclosed subject matter should not be limited to any single embodiment described herein, and the scope of the inventive concept should be determined in accordance with the following claims and their equivalents.

Claims

1. A defect inspection system for a sample, the defect inspection system comprising: an image sensor configured to capture a target image of the sample, the sample comprising a flat portion and a curved portion extending from the flat portion in a first direction and having a curvature, the target image comprising a first area corresponding to the flat portion of the sample and a second area corresponding to the curved portion of the sample; as well as a defect inspection device configured to determine a defect of the sample based on the target image, the defect inspection device comprising an image editor configured to enlarge a width of the second area along the first direction according to a resizing ratio, wherein the resizing ratio comprises: a first ratio determined based on a first angle between a third direction orthogonal to the flat portion and a fourth direction orthogonal to a first tangent plane at a first point of the curved portion, and Wherein, the first ratio is the secant value of the first angle.

2. The defect inspection system according to claim 1, wherein: The image editor is configured to separate the first region from the second region, generate a resized region by enlarging a width of the second region, and combine the first region with the resized region to generate an inspection image.

3. The defect inspection system according to claim 2, wherein: The defect inspection device further comprises: a defect detector configured to detect a defect area from the inspection image; and The defect identifier is configured to compare the size of the defect area with a reference range to determine whether the sample is normal.

4. The defect inspection system according to claim 3, wherein: The defect detector is configured to divide the inspection image into a plurality of regions based on a difference in information between pixels adjacent to each other in the inspection image, and select the defect region from the plurality of regions.

5. The defect inspection system according to claim 3, wherein: The defect identifier is configured to determine that the sample is abnormal when a size of the defect region is larger than the reference range.

6. The defect inspection system according to claim 1, wherein: The resizing ratio also includes: a second ratio determined based on a second angle between the third direction and a fifth direction orthogonal to a second tangent plane at a second point of the curved portion, wherein the second ratio is the secant value of the second angle, and The image editor is configured to enlarge the width of the second area according to the first ratio to generate a first inspection image, and to enlarge the width of the second area according to the second ratio to generate a second inspection image.

7. The defect inspection system according to claim 6, wherein: The defect inspection device further comprises: a defect detector configured to detect a first defect area from the first inspection image and a second defect area from the second inspection image; and A defect identifier is configured to determine that the sample is abnormal when the size of the first defect area is larger than a reference range or when the size of the second defect area is larger than the reference range.

8. A defect inspection method for a sample, the defect inspection method comprising the following steps: capturing a target image of the sample, the sample comprising a flat portion and a curved portion, the curved portion extending from the flat portion in a first direction and having a curvature with respect to a second direction intersecting the first direction; extracting a first area corresponding to the flat portion and a second area corresponding to the curved portion from the target image; enlarging a width of the second area corresponding to the first direction according to a resizing ratio to generate an inspection image; and Determining whether the sample is normal based on the inspection image, wherein the resizing ratio comprises: a first ratio determined based on a first angle between a third direction orthogonal to the flat portion and a fourth direction orthogonal to a first tangent plane at a first point of the curved portion, and Wherein, the first ratio is the secant value of the first angle.

9. The defect inspection method for a sample according to claim 8, wherein: The resizing ratio further includes: a second ratio determined based on a second angle between the third direction and a fifth direction orthogonal to a second tangent plane at a second point of the curved portion, wherein the second ratio is the secant value of the second angle, and The step of generating an inspection image includes: enlarging the width of the second area according to the first ratio to generate a first inspection image, and enlarging the width of the second area according to the second ratio to generate a second inspection image.

Images