JP2012198071A - Device and method for inspecting optical glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for inspecting an optical glass that allow elimination of the influence, for example, of reflection of light transmitted through an optical glass.SOLUTION: The for inspecting an optical glass comprises: a mounting portion 21 on which a jig 30 holding a glass 35 is mounted; a driving device 22 for displacing the mounting portion 21 to position the glass 35 in an inspection region; a light source 15 and an optical system 10 disposed on one side of the mounting portion 21; and a reflector 40 disposed on the other side of the mounting portion 21 and having a reflecting surface inclined with respect to an optical axis of the optical system. The jig 30 having a jig opening 31c extending between its top and bottom surfaces and glass holding means 32 for holding the glass 35 in a region adjacent to the jig opening 31c is used. Accordingly, it becomes possible to prevent the inspection region from being intersected by an optical path of the reflected light in which the light applied from the light source 15 to the inspection region passes through the glass 35, the jig opening 31c and a mounting portion opening 21c, and then is incident on and reflected off the reflector 40.

Description

  The present invention relates to an optical glass inspection apparatus such as a cover glass and a cover lens used in an optical apparatus such as a digital camera, and an inspection method.

  Optical cameras such as cameras, especially digital cameras that are miniaturized and integrated with mobile phones, protect the lens by placing a cover glass (hereinafter sometimes referred to as optical glass or glass) in front of the hands. is doing. With such glass, as the image sensor is miniaturized, if there are small scratches or spots, the captured image may be stained. Some glass is coated with an interference film serving as an optical filter such as an infrared cut filter, and some glass is formed with an anti-reflection coating film for increasing the transmittance. Since these scratches and the like on the coating film also cause stains on the image, a technique for reliably and promptly inspecting the scratches has been developed.

  For example, this is a technique for obtaining the front and back images of glass using a video camera and inspecting for the presence or absence of scratches or dirt (Patent Document 1). In this inspection technique, the glass held by the jig is irradiated with light to determine the presence or absence of glass scratches or the like. Here, the jig is mounted on a table, a video camera is disposed above the vertical direction of the glass, a plurality of light sources are disposed obliquely above the glass, and the video camera is obtained by the irradiation light of these light sources. The obtained shadow image is converted into an electric signal to be a video signal, and the video signal is subjected to a predetermined process to inspect a scratch or the like.

  In this inspection, a large number of glasses are placed in the vertical and horizontal directions of the jig, and the table moves in the vertical and horizontal directions to position any glass at the imaging position of the video camera. The light applied to the glass is not detected by the video camera because it passes through the glass unless the glass is scratched. However, if there is a scratch or the like on the glass, a video image is detected by the video camera by light reflected or scattered by the scratch or the like. In the case of visual observation, scratches and the like can be detected with a microscope.

  However, a small amount of light transmitted through the glass is reflected or scattered in the surface region of the jig facing the back surface of the glass. This is because it is difficult to reduce the reflectance to about several percent (for example, 2 to 4%) or less even if the jig is subjected to non-reflective black processing or the like. Moreover, a jig for inspecting a large number of glasses in a short time has a shape like a tray, and the distance between the glass back surface and the surface area of the jig is about several mm (for example, 1 to 2 mm). Therefore, reflected light, scattered light, etc. (hereinafter sometimes referred to as background noise) on the surface area of the jig may interfere with detection of scratches and the like.

  If we try to improve the discrimination between background noise and images of scratches, etc., it will depend on the skill of the inspector, and it will take time to inspect and cause fatigue of the inspector. Problem arises. In the case of inspecting with a video signal obtained by a video camera, the separability is improved by devising the video processing, but the processing time is increased and the apparatus is complicated.

JP 2009-085617 A

  Therefore, in order to solve the above problems, the present invention can eliminate the influence of reflected light or scattered light on the surface area of the jig of the light transmitted through the optical glass mounted on the jig. An object of the present invention is to realize an optical glass inspection apparatus and an inspection method capable of improving the accuracy and speeding up inspection of scratches and the like (reducing inspection costs).

  The optical glass inspection apparatus according to the present invention includes a mounting portion for mounting a jig holding glass (for example, a table on which a jig is mounted) and a jig mounted on the mounting portion by displacing the mounting portion. A driving device for positioning the held optical glass in a predetermined inspection area, a light source for irradiating the inspection area with light from one side (for example, above) of the mounting portion, and an optical glass positioned in the inspection area An optical system for detecting reflected light (for example, a microscope in the case of visual inspection, a video camera or the like in the case of automatic inspection), and the other side (for example, below) of the mounting portion, The reflecting surface has a reflecting portion inclined with respect to the optical axis of the optical system. Here, the mounting portion has a mounting portion opening that communicates the one side with the other side.

  The optical glass inspection apparatus has, as a jig, a jig having one or a plurality of jig openings for communicating the front and back surfaces thereof, and glass holding means for holding the optical glass in a region adjacent to the jig opening. At that time, the jig opening is positioned at a position opposite to the mounting portion opening.

  In the optical glass inspection apparatus, if there is a scratch or a stain on the glass, the light irradiated to the inspection area from the light source is reflected or scattered by the scratch or the like and detected as a scratch by the optical system. On the other hand, light that has not been reflected or scattered by scratches or stains on the glass passes through the glass, the jig opening, and the mounting part opening and enters the reflecting part. While the incident light to the reflecting part is absorbed by the reflecting surface, a part of it is reflected, but the optical path of the reflected light does not cross the inspection region.

  For example, when the crossing angle between the reflecting surface and the optical axis of the optical system is 45 degrees, the light incident on the reflecting surface through the optical path parallel to the optical axis has an incident angle and a reflection angle of 45 degrees. It is reflected and does not return to the inspection area of the optical glass held by the jig. When the inspection area is orthogonal to the optical axis of the optical system, the reflected light from the reflecting surface passes through the reflected optical path (optical path parallel to the jig) orthogonal to the incident light and becomes a jig. Dont return. Since the light transmitted through the glass and directed toward the reflecting portion does not return to the optical system that detects the reflected light and scattered light from the glass, it does not affect the inspection of the scratches on the glass. Of course, it is desirable that the reflecting portion is painted in black or the like having a low reflectance (several percent).

  Furthermore, it is desirable to dispose light reflected from the reflecting portion by disposing a light absorbing portion having a low reflectance on the reflected light path. In addition, when inspecting, whether it is visual inspection or inspection with a video camera, the glass is focused, so the reflected light from the reflection part and light absorption part is not imaged at the imaging position of the optical system, but background noise. It is hard to become.

  Moreover, you may arrange | position the light absorption part which has a light absorption surface in which the light quantity of reflected light and scattered light is very small instead of a reflection part in the position which arrange | positions a reflection part. In this case, the amount of light returning to the inspection region is very small, and the light absorbing portion is out of the focus of the optical system, so that it is difficult to cause background noise.

  By the way, the glass inspection apparatus is desirably used in a light-shielding environment, and at least the space on the optical path side (the other side of the mounting portion) through which light transmitted through the glass passes is desirably in a light-shielding environment.

  As described above, according to the present invention, it is possible to eliminate the influence of the light transmitted through the optical glass mounted on the jig, the reflected light or the scattered light in the surface area of the jig, It is possible to realize an optical glass inspection apparatus and inspection method that can improve the accuracy and speed of inspection (can reduce the inspection cost).

It is a figure which shows an example of schematic structure (a part is cross-sectional schematic structure) in one Example (Example 1) of the optical glass test | inspection apparatus concerning this invention. It is a figure which shows an example of schematic structure of the jig | tool used with the optical glass inspection apparatus shown in FIG. 1, The same figure (a) shows the schematic structure of the planar view, The same figure (b) is the glass mounting. The schematic structure of the placement unit in plan view is shown, and FIG. 8C is a diagram showing the schematic cross-sectional structure of the glass placement unit. It is a figure which shows schematic structure in the modification of the reflection part in the optical glass inspection apparatus shown in FIG. It is a figure which shows schematic structure in the other modification of the reflection part in the optical glass inspection apparatus shown in FIG. It is a figure which shows an example of schematic structure (a part is cross-sectional schematic structure) in the other Example (Example 2) of the optical glass inspection apparatus concerning this invention.

  Hereinafter, an embodiment of an optical glass inspection apparatus and inspection method according to the present invention will be described with reference to the drawings.

  An optical glass inspection apparatus 1 (Example 1) according to the present invention shown in FIG. 1 includes a microscope (optical system) 10, a light source 15, a horizontally positioned table 21, and a drive device 22 that drives the table 21. The positioning mechanism 20, the black reflecting portion 40, and the black light absorbing portion 50 are provided.

(microscope)
The microscope 10 includes an objective lens 11 (hereinafter referred to as a lens 11), a microscope main body 12, and an eyepiece lens 13. The microscope 10 is disposed above a horizontally positioned table 21, and an optical axis 11x of the lens 11 is set. It is orthogonal to the table 21.

  In the vicinity of the optical axis 11x, a light source 15 having two light sources 15a and 15b is provided integrally with the microscope main body 12. The light emitted from the light sources 15a and 15b is applied to the table 21 as a relatively narrow light beam in an area substantially parallel to the optical axis 11x (in the area indicated by the alternate long and short dash lines 15x and 15y in FIG. 1). The

(Positioning mechanism)
The positioning mechanism 20 includes a table 21 and a driving device 22 for displacing the table 21 in two directions orthogonal to each other on a horizontal plane. The table 21 has a table opening 21c that communicates the front surface (one side surface) 21a and the back surface (the other side surface) 21b in a substantially central region. On the surface 21a of the table 21, a jig positioning portion 21d is formed so as to protrude so as to surround the table opening 21c. The driving device 22 may be any device that is controlled by a control device including a computer or the like, or a device that manually displaces the table 21, and the purpose thereof is movable to determine the position by displacing the table 21. What is necessary is just to have a part etc.

(jig)
As shown in FIG. 2A, the jig 30 has a substantially rectangular shape in a plan view, and is arranged in a glass plate portion 31n (n = 1, 2, ... n). The glass placing portion 31n has a rectangular shape in plan view. As shown in FIG. 2 (b) in a plan view and a cross-sectional configuration in FIG. 2 (c), the glass mounting portion 31n has a rectangular shape in which the front surface 30a and the back surface 30b of the jig 30 communicate with each other. It has a glass holding frame 32a formed so as to protrude from the surface 30a at the periphery of the tool opening 31c and the jig opening 31c. Between the glass holding frame 32a and the jig opening 31c, a glass support portion 32b parallel to the surface 30a of the jig 30 is formed.

  The glass holding frame 32a and the glass support portion 32b form a rectangular glass holding means 32 as shown in FIG. 2B, and the glass 35 is placed at a position defined by the glass holding means 32. Can be positioned. Here, it is desirable that the glass support portion 32b supporting the four sides of the glass 35 be as narrow as possible. This is because by making the glass support portion 32b as narrow as possible, the area where the glass 35 and the glass support portion 32b are in contact with each other is made as narrow as possible, and the surface of the glass 35 can be prevented from being scratched. In addition, a slight gap is formed between the wall surface of the glass holding frame 32a and the four side peripheral surfaces of the glass 35 so that the glass 35 can be placed on the glass holding means 32 smoothly. .

  When the jig 30 is mounted on the table 21, the mounting position is defined by the jig positioning portion 21d, and all the jig openings 31c are positioned above the table openings 21c (in FIG. 1). Of course, by displacing the table 21 with the driving device 22, any glass placing portion among all the glass placing portions 31n can be positioned on the optical axis 11x.

(Reflection part)
The black reflecting portion (reflecting plate) 40 crosses the optical axis 11x at a crossing angle θ (for example, θ = 45 degrees) below the table 21 and at a position P on the optical axis 11x. Here, the reflecting surface 40a of the reflecting portion 40 is a flat surface. Therefore, at the position P, the incident angle and the reflection angle are 45 degrees, and the optical axis 40 x of the reflected light is parallel to the table 21. The reflection surface 40a has, for example, a reflectance of about 2 to 4%, and has an area that can almost catch the light beam emitted from the light source 15 (a chain line indicating the width of the light beam from the light source 15). It is desirable that both 15x and 15y intersect the reflecting portion 40).

(Light absorption part)
In the direction of the optical axis 40x of the reflected light, a light absorbing portion 50 having a low-reflectance (black) light absorbing surface 50a orthogonal to the optical axis 40x is disposed, and the reflected light from the reflecting surface 40a is It is almost absorbed by the light absorber 50. The optical glass inspection apparatus 1 is desirably used in a light-shielding environment. In FIG. 1, it is desirable that at least the space below the table 21 be a light-shielding environment. In such a light shielding environment, the light reflected by the reflecting portion 40 is almost absorbed by a black light shielding curtain or the like (functioning as a light absorbing portion), and thus the light absorbing portion 50 may be omitted.

(Optical glass inspection)
The inspection of the glass 35 by the optical glass inspection apparatus 1 is performed according to the following procedure. The glass 35 cut into a predetermined shape is placed on the glass placement portion 31n of the jig 30 by a pickup device (not shown). Next, the jig 30 holding the glass 35 is mounted at a position defined by the jig positioning portion 21 d of the table 21. At this time, in the jig 30 mounted on the table 21, all the glass placing portions 31n are positioned above the table opening 21c.

  An inspector (a control device (not shown in the case of automatic inspection)) detects an image due to scratches, stains, or the like on the glass 35 while the lens 11 is focused on the glass 35. At this time, the focal depth of the lens 11 is preferably shallow. For example, it is desirable that the front surface and the back surface of the glass 35 are included within the range of the depth of focus, and the reflecting portion 40 is outside the range.

  Detection of scratches or the like is performed on the glass placement portion 31n of the jig 30 in the order of n = 1, 2,. Specifically, the table 21 is displaced two-dimensionally in the horizontal direction by the driving device 22 so that all the glass placing portions 31n are sequentially positioned on the optical axis 11x. The light beam irradiated by the light source 15 is irradiated almost uniformly on the glass mounting portion 31n intersecting with the optical axis 11x or on a plurality of glass mounting portions 31n in the vicinity thereof.

  When the glass 35 is inspected one by one, the area of the glass placement portion 31n positioned on the optical axis 11x becomes the inspection area. In the case of inspecting a plurality of glasses 35 held on a plurality of glass placing portions 31n positioned adjacent to the optical axis 11x and a plurality of adjacent glass placing portions, a region including these glass placing portions. Becomes the inspection area. In any inspection region, it is desirable that the light beam irradiated by the light source 15 is not irradiated outside the inspection region.

  Detection of scratches and the like is performed as follows. When the glass 35 positioned in the inspection region has scratches or spots, reflected light or scattered light is generated according to the properties of these scratches or spots. These reflected lights and the like are captured by the microscope 10 and inspected for scratches. Alternatively, an image such as a scratch may be converted into a video signal by a video camera, and a predetermined process may be performed on the image signal to automatically inspect the scratch or the like.

  When the glass 35 positioned in the inspection area is not damaged or stained, the irradiated light passes through the glass 35 and passes through the jig opening 31c and the table opening 21c to reach the reflecting portion 40. Here, since the reflecting surface 40a is black and has a reflectance of about 2 to 4%, it absorbs most of the incident light, but the light that has not been absorbed becomes reflected light or scattered light. Here, the reflected light passes through the optical axis 40x and the vicinity thereof and reaches the light absorption surface 50a of the light absorbing portion 50 (for example, black and has a reflectance of about 2 to 4%) and is absorbed.

  On the other hand, a part of the scattered light generated on the reflection surface 40a can be scattered in the direction of the inspection region. However, since the scattered light in the direction of the inspection region is extremely small, the reflection surface 40a is outside the focal point of the lens 11, so that inspection of scratches and the like is not hindered.

  Although the light reflected or scattered by the light absorption unit 50 may be directed to the reflection unit 40 and the inspection region, the amount of light reflected twice by the reflection surface 40a and the light absorption surface 50a having a low reflectance is extremely high. There are few. In addition, since the reflecting part 40 and the light absorbing part 50 are out of the focus of the lens 11, such reflected light and scattered light do not hinder the inspection of scratches and the like.

  The crossing angle between the light absorption surface 50a and the optical axis 40x may be set as appropriate so that the reflection direction at the light absorption surface 50a is a direction other than the inspection region (for example, downward in FIG. 1). Also for the optical axis 40x, the crossing angle θ between the reflecting surface 40a and the optical axis 11x may be set to 45 degrees or less and away from the table 21 (may be directed downward in FIG. 1).

  In addition, although the reflective surface 40a was illustrated as a plane, it is good also considering the reflective surface 40a as a curved surface. Since the curved surface can be considered as a set of minute planar regions, it is sufficient that the inspection region is not disposed in the optical axis direction of the reflected light in these minute planar regions.

(Modification 1)
FIG. 3 is a diagram illustrating a schematic configuration of a reflection unit 41 which is a modification of the reflection unit 40. The reflecting portion 41 has a black reflecting portion main body 42 having a substantially rectangular parallelepiped shape, and a groove portion 43n (n = 1, 2,...) Drilled in a V shape on the surface 42a of the reflecting portion main body 42. . One inclined surface of the groove 43n is provided with a black reflecting surface 44n, and the other inclined surface opposite thereto is provided with a reflecting surface 45n, and all the reflecting surfaces are black. Here, the reflecting surface 44n and the reflecting surface 45n intersect the surface 42a at, for example, about 60 degrees.

  The reflecting portion 41 is disposed below the table 21, and is positioned so that the front surface 42a faces the back surface 21b of the table 21 and is orthogonal to the optical axis 11x. Further, the groove 43n of the reflecting portion 41 is positioned so as to catch most of the light beam from the light source 15 at the position P in FIG.

  Therefore, the light that has passed through the glass 35 and passed through the jig opening 31c and the table opening 21c and reached the reflecting portion 41 is absorbed by the reflecting surface 44n or the reflecting surface 45n of the groove 43n. Here, slight reflected light or scattered light may be generated, but the reflected light or the like at the reflecting surface 44n is almost absorbed by the reflecting surface 45n, and the reflected light or the like at the reflecting surface 45n is almost absorbed by the reflecting surface 44n. The light returning to can be ignored.

(Modification 2)
FIG. 4 is a diagram illustrating a schematic configuration of a reflection portion 41 ′ that is another modification of the reflection portion 40. The reflecting portion 41 ′ includes a black reflecting portion main body 46 having a substantially flat plate shape and a reflecting plate 47n (n = 1, 2,...) Obliquely provided on the surface 46a (for example, the reflecting portion). The main body 46 and the reflector 47n cross each other at 60 degrees.) One inclined surface of the reflecting plate 47n is a reflecting surface 48n, and the opposite inclined surface is a reflecting surface 49n, and all the reflecting surfaces are black.

  The reflecting portion 41 ′ is disposed perpendicular to the optical axis 11 x and below the table 21, and is positioned so that the front surface 46 a of the reflecting portion main body 46 faces the back surface 21 b of the table 21. The reflector 47n is positioned so as to capture most of the light beam from the light source 15 at the position P in FIG. Here, when the reflecting portion main body 46 is viewed in plan from above on the optical axis 11x, the surface 46a of the reflecting portion main body 46 is blocked by the reflecting plate 47n.

  Therefore, the light that has passed through the glass 35, passed through the jig opening 31c and the table opening 21c, and reached the reflecting portion 41 'is absorbed by the reflecting surface 48n of the reflecting plate 47n. At this time, several percent of reflected light or scattered light is generated, but the reflected light or the like at the reflecting surface 48n is absorbed by the reflecting surface 49n. The light reflected by the reflecting surface 48n and the reflecting surface 49n at least twice is a slight amount of light, but eventually reaches the surface 46a of the reflecting portion main body 46 and is absorbed, so that the scattered light returns in the direction of the inspection region. Can be ignored.

  Next, an optical glass inspection apparatus 2 (Example 2) according to the present invention will be described. In addition, about the component which has the same function as Example 1, the same code | symbol is attached | subjected and those description is abbreviate | omitted.

  As shown in FIG. 5, the light absorbing portion 50 is disposed so as to be orthogonal to the optical axis 11 x and below the table 21, and its front surface 50 a is opposed to the back surface 21 b of the table 21. For example, the surface 50a is covered with black felt. On the surface 50a, most of the incident light is absorbed and a slight amount of scattered light is scattered, but almost no light returns to the inspection region. Further, since the focus of the lens 11 is out of the light absorbing portion 50, the inspection of scratches and the like is not hindered by the scattered light. The light absorbing unit 50 may be disposed in parallel with the table 21 or may be disposed so as to be inclined with respect to the table 21.

  The optical glass inspection apparatus and the inspection method according to the present invention have been described above. However, the present invention is not limited to the configuration of each embodiment, and can be modified without departing from the spirit of the present invention. . For example, in each embodiment, a small optical glass used in a small digital camera or the like has been described as an inspection target. However, the optical glass inspection apparatus and the inspection method according to the present invention do not depend on the size of the glass. However, by appropriately setting the dimensions of the optical glass inspection device, for example, it can be applied to inspection of glass or the like for protecting the surface of a flat-screen image display device.

  Since the optical glass inspection apparatus according to the present invention can be manufactured, sold and used, and the optical glass inspection method according to the present invention can be used in the inspection of optical glass, both have economic value. And has industrial applicability.

1, 2 Optical glass inspection device 10 Microscope (optical system)
11 Objective lens 11x Optical axis of lens (optical axis of optical system)
15 Light source 21 Table (mounting part)
21a Table surface (one side of the mounting part)
21b The back of the table (the other side of the mounting part)
21c Table opening (mounting part opening)
22 Driving device 30 Jig 30a Jig surface 30b Jig back surface 32 Glass holding means 31c Jig opening 31n Glass placing part 35 Optical glass (glass)
40, 41, 41 'Reflection part 40a Reflection surface 50 Light absorption part

Claims (5)

An optical glass inspection device,
A mounting portion for mounting a jig holding optical glass;
A driving device that displaces the mounting portion and positions the optical glass held by the jig mounted on the mounting portion in a predetermined inspection region;
A light source for irradiating the inspection area with light from one side of the mounting portion;
An optical system that is disposed on one side of the mounting portion and detects reflected light from the optical glass positioned in the inspection region;
A mounting portion opening disposed on the other side of the mounting portion, the reflection surface of which is inclined with respect to the optical axis of the optical system, and the mounting portion communicates the one side with the other side. Have
By using a jig having glass holding means for holding the optical glass in an adjacent region of the jig opening and one or a plurality of jig openings communicating the front surface and the back surface as the jig. ,
An optical path of reflected light of light that is irradiated from the light source to the inspection area, passes through the optical glass, the jig opening, and the mounting portion opening, and further enters and reflects the reflection portion, and the inspection region. Optical glass inspection apparatus characterized by not crossing.   The optical glass inspection apparatus according to claim 1, wherein the reflecting surface of the reflecting portion is black.   The optical glass inspection apparatus according to claim 1, further comprising a light absorbing portion disposed on an optical path of the reflected light. An optical glass inspection device,
A mounting portion for mounting a jig holding optical glass;
A driving device that displaces the mounting portion and positions the optical glass held by the jig mounted on the mounting portion in a predetermined inspection region;
A light source for irradiating the inspection area with light from one side of the mounting portion;
An optical system that is disposed on one side of the mounting portion and detects reflected light from the optical glass positioned in the inspection region;
A light absorbing portion disposed on the other side of the mounting portion, and the mounting portion has a mounting portion opening that communicates one side with the other side,
By using a jig having glass holding means for holding the optical glass in an adjacent region of the jig opening and one or a plurality of jig openings communicating the front surface and the back surface as the jig. ,
An optical glass inspection apparatus, wherein light that has been irradiated from the light source onto the inspection region and passed through the optical glass, the jig opening, and the mounting portion opening is incident on the light absorbing portion. An optical glass inspection method,
Holding the optical glass in the glass holding means provided in the adjacent region of the jig opening that communicates the front and back surfaces of the jig;
Mounting the jig on the mounting portion such that the jig opening faces the mounting portion opening of the mounting portion;
Displacing the mounting portion and positioning the optical glass held by the jig mounted on the mounting portion in a predetermined inspection region;
Irradiating the inspection area with light from one side of the mounting portion;
A step of detecting reflected light or scattered light from the optical glass positioned in the inspection area with an optical system disposed on one side of the mounting portion, and
The light irradiated to the inspection region is transmitted through the optical glass and further passed through the jig opening and the mounting portion opening, and is disposed on the other side of the mounting portion, and the reflection surface of the optical system Reflected by a reflecting portion inclined with respect to the optical axis, and the optical path of the reflected light should not cross the inspection area,
Alternatively, the light irradiated to the inspection area is transmitted through the optical glass and further passed through the jig opening and the mounting portion opening, and is absorbed by the light absorbing portion disposed on the other side of the mounting portion. An optical glass inspection method characterized by the above.

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