TW201843008A - Edge processing of glass for light coupling - Google Patents

Abstract

Methods and apparatus for finishing an edge of a glass sheet are described. The edge of the glass sheet is finished using two grinding wheels mounted on spindles so that the edge of the grinding wheels chamfer the edge of the glass sheet during relative movement of the grinding wheels and the glass sheet.

Description

Glass edge processing for optical coupling

This application claims the priority right of US Provisional Patent Application No. 62/490869, which was filed on April 27, 2017 in accordance with the patent law. The reference of this application is in combination with the disclosure of the above US patent application.

Embodiments of the present disclosure are directed to an apparatus and method for processing an edge of a glass sheet. Specifically, embodiments of the present disclosure are directed to an apparatus and method for processing an edge of a glass sheet to increase optical coupling through the glass sheet.

In manufacturing various products (such as light guide plate (LGP), the light guide plate (LGP) is used to evenly distribute light on the display panel in the backlight of edge-emitting liquid crystal display (LCD) devices), grinding and Polishing the edges of the glass sheet to finish the glass sheet. Side-illumination type backlight units of such devices include LGPs typically made of high-transmittance plastic materials such as polymethyl methacrylate (PMMA). Challenges due to the use of polymer light guides (LGP) limit the trend for thinner displays. Although this plastic material exhibits excellent properties (such as light transmission), these materials have relatively poor mechanical properties (such as rigidity, coefficient of thermal expansion (CTE), and hygroscopicity). In particular, polymer LGP lacks the dimensional stability required for ultra-thin displays. When the polymer light guide plate is heated and wet, the light guide plate may warp and expand, which is disadvantageous to the mechanical properties of the light. The instability of polymer LGP requires designers to add wider bezels and thicker backlights with air gaps to compensate for this movement.

Glass flakes have been proposed as LGP replacement solutions for displays, but glass flakes must have appropriate properties to achieve sufficient optical performance in terms of transmission, scattering, and light coupling. The glass sheet used for the light guide plate must meet edge specifications such as perpendicularity, straightness, and flatness. Corning Corporation sells Corning Iris ^TM glass as an alternative to PMMA for LGP and other transparent plastic materials. Iris ^™ glass is very transparent and has absorption or scattering losses as low as 0.2 dB / m or less in the visible wavelength range of 450-650 nm for light propagation guided along the LGP and guided by total internal reflection. In addition, the CTE of glass is much lower than the CTE of suitable plastics, and is closer to the CTE of LCD display panels, making assembly of large-sized flat-screen TVs easier. In addition, excellent mechanical strength and rigidity, as well as low CTE, allow a significant reduction in the thickness of the LCD bezel.

One of the important requirements for the light guide plate is the effective optical coupling between the light emitting diode (LED) and the light guide plate. Coupling benefits from the reduced gap between the LED and the edge of the LGP and provides maximum surface area on the edge to allow the most optical coupling to pass through. This is different from the traditional display glass manufacturing process, which focuses on creating rounded edges with a diffusing surface to defeat modes of impact and chipping and other transportation related modes. Therefore, there is a need in the art to which the present invention pertains to an apparatus and method for providing a glass light guide plate with enhanced light coupling efficiency.

A first aspect of the present disclosure relates to an apparatus for finishing the edges of a glass sheet by grinding the edges of the glass sheet. In one or more embodiments, such equipment includes a table that supports a glass sheet when the edges are subjected to grinding and polishing. The X axis is the direction of lateral movement on one plane of the glass sheet on the table. The Y axis is the direction of longitudinal movement on the plane perpendicular to the X axis. The Z axis is a direction of orthogonal movement with respect to the plane. The first motor is positioned on a first side of the plane. The first motor has a first spindle, and the first spindle has a first rotating spindle axis aligned substantially along the X axis. The second motor is positioned on a second side of the plane. The second motor has a second spindle having a second rotating spindle axis aligned substantially along the X axis. The first grinding wheel is mounted on the first spindle. The first grinding wheel has a substantially dish shape with a peripheral edge, so that the first edge of the glass sheet is chamfered using the peripheral edge of the first grinding wheel. The second grinding wheel is mounted on the second spindle. The second grinding wheel is substantially dish-shaped with a peripheral edge, so that the second edge of the glass sheet is chamfered by using the peripheral edge of the second grinding wheel.

A second aspect of the present disclosure relates to a method for finishing the edges of a glass sheet. The methods include supporting a glass sheet on a workbench, wherein a portion of the glass sheet extends a distance from the workbench. The glass sheet includes a first surface, a second surface, and an end surface, and the second surface is opposite to the first surface. The first surface and the end surface intersect along a first edge, and the second surface and the end surface intersect along a second edge. The X axis is the direction of lateral movement on a plane of the glass sheet on the surface. The Y axis is the direction of longitudinal movement on the plane perpendicular to the X axis. The Z axis is a moving direction orthogonal to the plane. The first edge is in contact with a peripheral edge of at least one first grinding wheel positioned on a first main axis of the first motor, and the first grinding wheel is substantially dish-shaped. The second edge is in contact with a peripheral edge of at least one second grinding wheel positioned on a second main axis of the second motor, and the second grinding wheel is substantially dish-shaped. During the first and second grinding wheels contacting the first and second edges, respectively, a relative movement is generated between the first and second grinding wheels and the glass sheet, so that the first and second edges become chamfered.

Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying examples and drawings.

In the following description, the same numerals represent the same or corresponding elements in the several views shown in the drawings. It should also be understood that terms such as "top," "bottom," "outward," and "inward" are convenient terms and are not to be considered as limiting terms unless otherwise specified. In addition, whenever a group is described as including at least one of a group of elements and combinations thereof, it should be understood that the group may include any number of the elements individually or in combination with each other, substantially by any A number of the elements is composed of or consists of any number of the elements. Furthermore, whenever a group is described as consisting of at least one of a group of elements or a combination thereof, it should be understood that the group may be composed of any number of the elements individually or in combination with each other. Unless stated otherwise, when a range of values is stated, the range of values includes the upper and lower limits of the range and any range therebetween. As used in this specification, unless otherwise stated, the indefinite articles "a", "an" and the corresponding definite article "the" means "at least one" or "one or more". It should also be understood that the various features disclosed in this specification and drawings can be used in any and all combinations.

This description describes a method and apparatus for finishing the edge of a glass sheet. In a specific embodiment, the glass sheet is refined by grinding and polishing to provide a light guide plate that can be used in a backlight unit according to an embodiment of the present disclosure. In a specific embodiment, a light guide plate is provided, which has similar or better optical properties to a light guide plate made of PMMA, and has better mechanical properties under high humidity conditions than a PMMA light guide plate ( Such as stiffness, coefficient of thermal expansion (CTE), and dimensional stability).

Some embodiments of the present disclosure provide methods and apparatus for generating a minimum chamfer on a glass light guide plate to achieve maximum optical coupling efficiency. Embodiments of the present disclosure can provide an LGP that can be used with thinner glass LEDs. For example, 1.5 millimeter (mm) LEDs can use 2mm thick LGP, but 1.0mm LEDs use 1.1mm thick LGP. Therefore, the optimal coupling efficiency of thinner LEDs requires minimal chamfering on the LGP. In addition, chamfering eliminates cantilever curl that occurs during separation and improves edge reliability by reducing the possibility of failure due to sharp features. Cantilever curl occurs where a portion of the top or bottom surface of the glass extends beyond the edge surface so that a local area of the top or bottom surface is not perpendicular to the edge surface. Cantilever curl can cause debris and breaks, and areas with cantilever curl are more vulnerable to impact damage.

Studies have shown that as the chamfer thickness increases from 50 to 200 microns (µm), the coupling efficiency decreases by about 5%. The normalized chamfer height versus thickness indicates that the coupling efficiency remains consistent in thickness. However, as the glass becomes thinner and the LED thickness is equal to the glass thickness, for a given chamfer height / thickness ratio, the coupling efficiency is more sensitive to the LED than the LGP gap.

Thin glass sheets provided to equipment manufacturers, such as electronic display manufacturers, typically include machined edges. That is, the edges are ground and shaped (such as chamfered) to eliminate sharp edges that are easily damaged and edge defects (chips, cracks, etc.) due to the cutting process, which may reduce the strength of the glass. The thickness of such a plate between the opposing major surfaces of the plate is generally equal to or less than about 2 mm, and preferably, the thickness is equal to or less than about 0.7 mm, and in some applications is equal to or less than about 0.5 mm. Very thin glass sheets can be 0.3 mm or less and still have the benefits of this disclosure.

It is known that the fracture of glass can be traced back to the initial defect, such as a small crack, and the fracture extends from this initial defect. Fractures can occur in a short period of time or gradually over an extended period of time, depending on the stresses present in the article. Nonetheless, each fracture begins with a defect, and the defect is most often found along the edge of the glass sheet, and especially the edge that has been previously scored and cut. To eliminate edge flaws, the edges of the plate can be ground or polished so that only the smallest defects remain, thereby increasing the strength of the sheet by spreading the stress required for the defects.

In addition, the grinding process itself is rarely uniform because when the abrasive wheel is across the edge of the glass, the grinding wheel may have a certain gap or change in its position. That is, the grinding wheel can be moved closer or further away from the glass sheet, so that the force exerted by the grinding wheel on the plate may change as a function of time and / or position. This change in position may cause a change in the amount of material removed from the edge. This change can lead to uneven grinding and changes in the amount of particles produced. More simply, the chamfer width may vary, and this change is most dramatic if the edges of the board subjected to grinding are rigid.

1A to 1C, exemplary end portions of a glass sheet 30 before and after edge finishing are illustrated. FIG. 1A shows the glass sheet 30 before edge finishing. The glass sheet 30 includes a first surface 31, a second surface 32, and an end surface 33, and the second surface 32 is opposite to the first surface 31. The first surface 31 and the end surface 33 intersect along the first edge 43, and the second surface 32 and the end surface 33 intersect along the edge 44.

1B and 1C show the glass sheet 30 after edge finishing. Here, the edges 43, 44 have been chamfered, and a first chamfer 41 and a second chamfer 42 are provided. First surface 31 intersects first chamfer 41 at edge 46, end surface 33 intersects first chamfer 41 at edge 47, end surface 33 intersects second chamfer 42 at edge 48, and second chamfer The corner 42 intersects the second surface 32 at the edge 49. The total thickness T _{g of the} glass sheet 30 includes the sum of the thickness T _{C1 of the} first chamfer 41, the thickness T _{e of the} end surface 33, and the thickness T _C2 of the second chamfer 42.

Some embodiments of the thickness of the combined first chamfer 41 of thickness T _C1 and T _C2 of the second chamfer 42 is less than about 10% of the total thickness of the T _g of the glass sheet 30. In some embodiments, the sum of the thicknesses T _C1 and T _C2 of the chamfers 41, 42 is less than about 5% of the total thickness T _g of the glass sheet 30. In some embodiments, the sum of the average thicknesses T _C1 and T _C2 of the chamfers 41, 42 is less than about 4%, 3%, 2.5%, 2%, 1.5%, or 1% of the total thickness T _g of the glass sheet 30. In some embodiments, the chamfers have an average of 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, or 90 μm. In some embodiments, the chamfer has an average thickness in a range of about 20 to about 80 μm, or in a range of about 20 to about 50 μm, or in a range of about 40 to about 80 μm.

The amount of particles generated during grinding of the first chamfer 41 and the second chamfer 42 (characterized by the chamfer widths W _C1 and W _{C2, respectively} ) should be minimized. The chamfer width is defined as the length of the chamfered surface from the edge surface 33 of the glass sheet 30 to the first surface 31 or the second surface 32 (which depends on which chamfer is measured).

Once a chamfer is created on the glass sheet, the resulting additional edges 46, 47, 48, 49 may be further polished to eliminate sharp corners at those edges and form a curved edge. This can be done, for example, by a buffing wheel and a suitable abrasive paste.

An embodiment of an apparatus 100 for processing a thin glass sheet 30 is shown in FIGS. 2 to 4. FIG. 2 shows a side view, FIG. 3 shows a top view, and FIG. 4 shows a perspective view of a similar device 100. The device 100 includes a table 116, which may also be referred to as a support surface. The X axis is the direction of lateral movement of the table 116 and / or the grinding wheel during edge processing. The Y axis is a longitudinal movement direction perpendicular to the X axis. The plane of the table 116 is in the X-Y plane formed by the X-axis and the Y-axis. The Z axis is orthogonal to the plane of the table 116. Although alternative configurations are possible, the illustrated embodiment provides a table 116 that supports the glass sheet 30 horizontally in the X-Y plane. In some embodiments, the table 116 supports the glass sheet 30 in a vertical orientation and moves up or down.

The apparatus 100 includes a first motor 120 having a first main shaft 121. The first main shaft 121 is oriented such that the rotation axis 122 is substantially aligned along the X axis. The first main shaft 121 is positioned on a first side of a plane of the table 116. The second motor 130 includes a second main shaft 131 that is oriented such that the rotation axis 132 is substantially aligned along the X axis. The second spindle 131 is positioned on the second side of the plane of the table 116. The second side of the plane of the table 116 is opposite the first side of the plane of the table 116. For example, if the plane of the table 116 is oriented horizontally, the first main axis 121 may be located above the plane, and the second main axis 131 may be located below the plane. When used in this manner, the term "substantially along the X axis" means that the axis of rotation is within ± 20º, ± 10º, ± 5º, ± 4º, ± 3º, ± 2º, or ± 1º of the X axis.

The device 100 includes a support 110 (shown in FIG. 4) that can hold and / or move the first motor 120 and / or the second motor 130. The support 110 may move the motor independently or together. In some embodiments, the first motor 120 is on the first support 110a and the second motor 130 is on the second support 110b, as shown in FIGS. 6A and 6B. The support 110 may include a Z-axis motor (not shown) to move the first motor 120 or the second motor 130 in a direction perpendicular to a main plane formed by the glass sheet 30.

The first grinding wheel 125 is connected to the first main shaft 121 and rotates about a rotation axis 122 of the main shaft 121. As will be understood by one of ordinary skill in the art to which this invention belongs, the grinding wheel may be connected to the spindle by any suitable means. The second grinding wheel 135 is connected to the second main shaft 131 and rotates about a rotation axis 132 of the main shaft 131. The grinding wheel can be mounted on the end of the main shaft or along the length of the main shaft.

The first grinding wheel 125 and the second grinding wheel 135 may be the same type of grinding wheels or may be different. In some embodiments, the first grinding wheel 125 and the second grinding wheel 135 are compliant urethane based wheels. The urethane-based wheel has a grinding element held together with a cross-linked urethane adhesive (for example, an industrial diamond maintained with a polyurethane matrix). In some embodiments, the urethane-based wheel has a Shore A hardness (ASTM D2240) in the range of about 80 to about 104 or in the range of about 84 to about 98. An exemplary grinding wheel 125 is shown in FIG. 5. The grinding wheel 125 may be a substantial dish member having an inner surface 126, an outer surface 127, and a peripheral edge 128. When used in this manner, the term "substantially dish-like" means that the grinding wheel has the approximate appearance of a dish or drum-like member having at least one face and a peripheral edge. The term inner face 126 refers to the face closer to the wheel 125 of the motor. The peripheral edge 128 provides an abrasive surface that contacts the glass sheet 30 during chamfering. The grinding wheel is aligned to rotate around the X axis to chamfer the edge of the glass sheet 30 using the peripheral edge 128. In some embodiments, the grinding wheel uses the edges of a round wheel that includes a recessed center region, commonly referred to as a cup-shaped "cup" wheel based on the grinding wheel.

The abrasive surface of the peripheral edge 128 typically includes diamond particles as a cutting medium dispersed in a suitable matrix or adhesive (such as a resin or metal bonded matrix). Other cutting media can also be used, such as carbide particles. The grinding wheel of some embodiments has an abrasive material having an average particle size in a range of about 200 μm to about 3 μm, or a range of about 150 μm to about 4 μm, or a range of about 120 μm to about 5 μm, or about 100 μm to about 6 μm Within a range of approximately 60 μm to approximately 7 μm, or within a range of approximately 50 μm to approximately 8 μm, or within a range of approximately 25 μm to approximately 10 μm. In some embodiments, according to the FEPA standard, the grinding wheel has a range of about P120 to about P6000, or a range of about P180 to about P3000, or a range of about P240 to about P2500, or about P360 to A particle size (grit) in a range of about P2000, or in a range of about P600 to about P1500, or in a range of about P800 to about P1200.

Referring again to FIG. 2, the glass sheet 30 is supported by the table 116 such that a portion 26 of the glass sheet 30 extends beyond the table 116. For example, the glass sheet 30 may be positioned in a horizontal arrangement as shown, where the glass sheet 30 may be cantilevered from what is referred to as a table 116 (also referred to as a support member or support surface). However, the glass sheet 30 may be fixed in any orientation and at any angle. For example, the glass sheet 30 may be supported in a vertical orientation. The apparatus 100 may further include a clamping member 117 including a guide rail, a finger, a hook, or other suitable clamping member for fixing the glass sheet 30 to the table 116. Another method of fixing the plate is by including a vacuum chuck in the table 116, which fixes the glass sheet. The vacuum can be used alone or in combination with one or more clamping members. Generally, as long as a portion 26 of the glass sheet 30 is positioned to extend from the fixture, any suitable method of fixing the glass sheet 30 to the table 116 may be used. In some embodiments, when the glass sheet 30 is securely attached, the extension portion 26 is capable of flexing relative to the holder. The glass sheet 30 may be fixed to the fixing device such that the extension portion 26 extends a predetermined distance L from the fixing device.

Referring to FIG. 7, the grinding wheels 125, 135 contact the glass sheet 30 so that the edges are chamfered. The round part of the grinding wheel may leave a slightly rounded chamfer corresponding to the shape of the grinding wheel. However, the amount of contact between the glass sheet 30 and the grinding wheel is small enough so that the chamfers look flat, or sufficient heat from friction causes the edges that have just been chamfered to flatten. The embodiment shown in FIG. 7 is enlarged to represent the angle of the cavity relative to the end surface 33 (measured based on the chamfered edges). The first grinding wheel 125 may form a first chamfer 41 having a first angle α with respect to the end surface 33. The second grinding wheel 135 is positioned so that the grinding surface of the second grinding wheel forms a second angle β with respect to the end surface 33. The first and second angles α, β may be substantially the same or different angles.

Referring to FIG. 2, an embodiment of the apparatus and method for removing the glass sheet 30 from the plane of the page, and referring to FIG. 7, the first grinding wheel 125 rotates about the rotation axis 122 and acts on the first surface 31 with a force F1. This force F1 can in turn produce a deflection δ1 in the glass sheet 30. That is, the glass sheet 30 is bent in response to the applied force. This can be roughly seen with the help of FIG. 8, which indicates that a force F is applied to the glass sheet 30, thereby causing a response in the form of a deflection δ. The amount of bending or compliance (the magnitude of δ) is a function of many variables including the material properties of the glass (such as Young's modulus), the amount of extension from the fixture, and the amount of force. These variables can be concentrated and characterized by a stiffness value k, where the stiffness is equal to the applied force divided by the resulting amount of deflection. The stiffness k can usually be expressed as The force F divided by the deflection δ is also proportional to the coefficient of elasticity E of the glass sheet multiplied by the moment of inertia I and divided by the cubic power of the glass sheet's extension L beyond the fixing device.

It also means that the amount of material removed by the grinding wheel is proportional to the force applied. From the above equation, it can be seen that in the presence of an applied force, the rigidity of a plate fully supported by a rigid support without an extension and without deflection in the plane of the glass sheet is infinite. In this case, an increase in force (such as the force exerted by the grinding wheel on the glass sheet) will result in a corresponding increase in the amount of material removed, and therefore the chamfer width. Such systems become unattractively sensitive to small changes in the position of the grinding wheel, which is often seen in real systems. This sensitivity can be within 1: 1, where twice the applied force results in twice the material being removed.

On the other hand, the above relationship also implies that if a portion of the plate extends through the fixture (such as beyond the table 116), the rigidity of the extended portion is reduced and limited, and the plate can be bent. For lower, limited stiffness, this compliance reduces the chamfer width. In other words, deflection caused by small position changes of the grinding wheel in contact with a plate with low stiffness (exhibiting compliance) can avoid material being removed compared to the same position movement relative to a rigid plate (such as high stiffness) A substantial increase. In addition, the level of accuracy of the chamfering equipment need not be as high as that required when the glass sheet does not exhibit compliance. This reduces equipment costs because, for example, bearing accuracy can be relaxed.

Those of ordinary skill in the art will understand that a similar set of environments may be depicted for the second grinding wheel 130. That is, consider that the second grinding wheel 28b is in contact with the second edge 44 and applies a force F2. However, since F2 is applied in a direction opposite to F1, the displacement of the extended portion of the glass sheet 30 occurs in a direction opposite to the deflection generated by the first grinding wheel 120.

According to an embodiment of the present disclosure, a plurality of grinding wheels are used to create chamfers on both edges of the end of the glass sheet bound by the fixing device, and wherein the glass sheet includes a glass sheet portion extending beyond the fixing device. At least two grinding wheels are employed and arranged such that each of the at least two grinding wheels engages one end of the glass sheet on the opposite side of the glass sheet. Each wheel rotates around a rotation axis and moves relative to the end of the glass sheet so that a double chamfer is formed along the end of the glass sheet.

For example, the first grinding wheel 120 forms a chamfer 41 along the first edge 43 of the glass sheet 30. In some embodiments, the angle α with respect to the chamfer of the plane of the end surface 33 is in a range of about 20 degrees to about 75 degrees, or in a range of about 30 degrees to about 70 degrees, or in a range of about 40 degrees to Within a range of approximately 65 degrees, or within a range of approximately 45 to approximately 65 degrees, or within a range of approximately 50 to approximately 65 degrees, or approximately 60 degrees. The second grinding wheel 130 similarly produces a second chamfer 42 at the second edge 44. In some embodiments, the chamfer angle β is in a range of about 20 to about 75 degrees, or in a range of about 30 to about 70 degrees, or in a range of about 40 to about 65 degrees, or in about 45 Within a range from about 65 degrees to about 65 degrees, or from about 50 degrees to about 65 degrees, or about 60 degrees.

In order to isolate the influence of the grinding wheels 120, 130, the grinding wheels 120, 130 are spaced apart by a predetermined distance _De , as shown in FIG. The magnitude of the predetermined distance is selected so that the force applied to the glass sheet 30 by one wheel does not affect the motion of the other wheel. In other words, the deflection from the plane of the glass sheet caused by one cup wheel will not cause the glass sheet to flex in the area of influence of the other cup wheels. Perhaps more simply, the deflection of the glass sheet produced by one grinding wheel from the plane will not overlap the deflection produced by the other grinding wheel. In some embodiments, the adjacent faces of the grinding wheel are at least about 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm.

Referring again to FIGS. 6A and 6B, the first motor 120 and / or the second motor 130 may be moved in the Z-axis to bring the motor, the main shaft, and the connected grinding wheel closer to or away from each other and move the table. The Z-axis movement allows the grinding wheels 125, 135 to be replaced and applies a controlled amount of force to the glass sheet 30. In some embodiments, the first motor 120 and / or the second motor 130 may move a distance on the Z axis, the distance being equal to or greater than about 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, or 80 mm from the table. FIG. 6A illustrates an embodiment in which the first motor 120 is mounted on a support 110 a different from the support 110 b of the second motor 130. The motors 120, 130 are in a processing position, in which the glass pieces passing through the grinding wheels 125, 135 will be edge processed. FIG. 6B illustrates a device in which the motors 120, 130, the main shafts 121, 131, and the grinding wheels 125, 135 move away from the processing position on the Z axis.

The first motor 120 and the second motor 130 may be configured to operate at any suitable speed. In some embodiments, the motor is configured to operate at a speed ranging from about 600 rpm to about 3000 rpm, or from about 800 rpm to about 2500 rpm, or from about 1000 rpm to about 2400 rpm, or at In the range of about 1500 rpm to about 2200 rpm.

Referring to FIG. 9, the first main shaft 121 and the second main shaft 131 are spaced apart by a distance D _a , which is sufficient to prevent the first grinding wheel 125 from contacting the second main shaft 131 or prevent the second grinding wheel 135 from contacting the first main shaft 121. In some embodiments, the distance between the first main shaft 121 and the second main shaft 131 is greater than or equal to the radius r _{1 of the} first grinding wheel 125 or the radius r _{2 of the} second grinding wheel 135 (whichever is greater), plus boundary of safety. In some embodiments, the safety margin is greater than or equal to about 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, or 15mm. In addition, the distance D _c between the centers of the thickness of the grinding wheel is sufficient to prevent adjacent faces of the grinding wheel from contacting.

The size of individual grinding wheels can be changed. In some embodiments, the grinding wheel has a radius in a range of about 25 mm to about 250 mm, or in a range of about 50 mm to about 200 mm, or in a range of about 75 mm to about 150 mm, or about 100 mm, or About 150mm or about 200mm.

FIG. 9 illustrates an embodiment in which each spindle 121, 131 has a single grinding wheel 125, 135. The illustrated main shafts 121, 131 have substantially the same length; however, it can be understood that the lengths of the main shafts 121, 131 can be different, and the positions of the grinding wheels 125, 135 on the main shafts 121, 131 can be controlled to prevent the Contact.

In some embodiments, the first spindle 121 and / or the second spindle 131 further include an additional grinding wheel. FIG. 10 illustrates an embodiment in which the first main shaft 121 has a single grinding wheel 125 and the second main shaft 131 has two grinding wheels 135a, 135b. The grinding wheels 135a, 135b are spaced along the length of the second main shaft 131, so that the grinding wheel 125 on the first main shaft 121 is located between the grinding wheels 135a, 135b. FIG. 11 illustrates another embodiment, in which the first main shaft 121 has two grinding wheels 125a and 125b and the second main shaft 131 has two grinding wheels 135a and 135b. The grinding wheels 125a, 125b are spaced along the length of the first main shaft 121, and the grinding wheels 135a, 135b are spaced along the length of the second main shaft 131, so that the grinding wheels on the main shaft are alternated, so that at least one of the grinding wheels 125a, 125b is One is located between the grinding wheels 135a, 135b, and at least one of the grinding wheels 135a, 135b is located between the grinding wheels 125a, 125b.

The width of the grinding wheel can be changed to provide a sufficient contact length with the glass sheet. In the embodiment of FIG. 9, the width W _{W1 of the} grinding wheel 125 and the width W _{W2 of the} grinding wheel 135 are each greater than or equal to about 25 mm, 28 mm, 30 mm, 35 mm, 40 mm, 45 mm, or 50 mm. In the embodiment of FIG. 10, the width W _{W1 of the} grinding wheel 125 is greater than or equal to about 25 mm, 28 mm, 30 mm, 35 mm, 40 mm, 45 mm, or 50 mm, and the combined width W _{W2a of the} grinding wheel 135a and the width W _{W2b of the} grinding wheel 135b Greater than or equal to about 25mm, 28mm, 30mm, 35mm, 40mm, 45mm, or 50mm. Wheels with larger contact lengths use less force per unit area than other identical wheels with less contact lengths.

FIG. 12 illustrates a schematic diagram of a device 100 according to one or more embodiments of the present disclosure. The grinding wheel 125 is connected to the first main shaft 121 and the first motor 120, and the grinding wheel 135 is connected to the second main shaft 131 and the second motor 130. Each of the first motor 120 and the second motor 130 is coupled to the controller 145 using a first force transducer 147 and a second force transducer 148, respectively. A force transducer is a component that converts a force into an electrical signal. For example, an exemplary force transducer has an electrical output range of 4 to 20 mA (this is equivalent to a force range of 0 to 100 N), matching the load to the transducer range. The force transducers 147, 148 may be any suitable force transducer capable of measuring a force within a predetermined range. The force transducer of some embodiments is operatively connected to the air bearing to provide a controlled amount of force to the motors 120, 130 to generate a controlled amount per unit area on the glass sheet 30 by the grinding wheels 125, 135 force. In use, the force transducer measures the force of the grinding wheel on the glass, and the feedback loop can adjust the air bearing (or other force transmission system) to apply the required force. In other words, the first motor 120 and the second motor 130 are pushed toward the surface of the table 116 so that if the motor is above the surface of the table, the motor will be pushed down by the force transducer. The force transducer together with the controller 145 provides a feedback system that can compensate the compliance of individual grinding wheels so that grinding wheels with different core materials can be used. The controller 145 may be any suitable controller, microcontroller, or computer, and may include, for example, a circuit, a central processing unit, a display unit, and / or an input / output unit. In some embodiments, the force transducer is configured to maintain the pressure of the grinding wheel against the glass at about 10N, 20N, 30N, 40N, or 50N or within a range of about 5 Newtons to about 75 Newtons, or at about 10 Newtons To about 50 Newtons.

The table 116 or suitable components coupled to the table may be configured to move the glass sheet 30 across the grinding wheel at any suitable speed. When used in this manner, the term "across the grinding wheels" does not imply the direction of the part or the physical orientation. Instead, the term is used to refer to the relative movement of the grinding wheel relative to the glass sheet, such that the edges of the glass sheet are chamfered by the grinding wheel. The stage 116 may be configured to move the glass sheet at a rate greater than or equal to about 5 m / min, 10 m / min, 15 m / min, 20 m / min, 25 m / min, or 30 m / min. In some embodiments, the table 116 is configured to move the glass sheet at a rate of about 5 m / min to about 30 m / min.

FIG. 13 illustrates an embodiment of the apparatus 100 including a cooling system 170 to prevent the glass sheet 30 or the grinding wheel from overheating. The first motor 120, the first main shaft 121, and the grinding wheel 125 are shown, but it should be understood that there may be two motors, a main shaft, or multiple grinding wheels. A single cooling system 170 may be used to cool multiple motors, spindles and / or grinding wheels, or each motor, spindle and / or grinding wheel may have a separate cooling system. The cooling system 170 may include a plurality of first peripheral liquid cooling nozzles 171 adjacent to the first main shaft 121. The plurality of first peripheral liquid cooling nozzles 171 may be aligned or positioned to direct the coolant toward the peripheral edge 128 of the grinding wheel 125 and / or toward the glass sheet. In some embodiments, the apparatus 100 includes a plurality of second peripheral liquid cooling nozzles adjacent to the second main shaft, and the plurality of second peripheral liquid cooling nozzles are positioned to guide the cooling liquid toward a peripheral edge of the second grinding wheel and / Or guide towards the edge of the glass sheet. The plurality of first peripheral liquid cooling nozzles and the plurality of second peripheral cooling nozzles may share a single cooling system 170, or each of the plurality of first peripheral liquid cooling nozzles and the plurality of second peripheral cooling nozzles may have individual independence. Cooling system.

In one or more embodiments, the cooling nozzle is positioned at a distance from the edge of the glass sheet and / or the peripheral edge 128 of the grinding wheel 125, the distance being in a range of about 10 cm to about 200 cm, or about 40 cm to about Within a range of 200 cm, or within a range of approximately 80 cm to approximately 200 cm, or within a range of approximately 100 cm to approximately 200 cm, or within a range of approximately 150 cm to approximately 200 cm. The cooling liquid may flow through the liquid coolant line 172 to the remote liquid cooling nozzle 171. The cooling system 170 may be supplied by a supply line (not shown), which may be connected to a coolant source (not shown, such as a tap that supplies tap water or a pump connected to a tank (not shown), which contains deionization And / or demineralized water).

In one or more embodiments, the cooling system 170 is configured to be activated during the chamfering of the glass sheet. The plurality of peripheral liquid cooling nozzles may include any suitable number of nozzles to provide sufficient cooling during grinding and / or polishing. The embodiment shown in FIG. 13 has two nozzles 171, but those having ordinary skill in the art will understand that more or fewer nozzles may be used. For example, three, four, five, six, seven, eight, nine, ten, eleven, or twelve peripheral liquid cooling nozzles may be provided. Likewise, the plurality of second peripheral liquid cooling nozzles may include any suitable number of nozzles to provide sufficient cooling during grinding.

The distal liquid cooling nozzle 171 may be spaced any suitable distance from the edge of the glass sheet 30 or the peripheral edge 128 of the grinding wheel 125 during chamfering. During operation, the distal liquid cooling nozzle 171 may be spaced 5cm, 10cm, 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 50cm, 60cm, 70cm, 80cm, 90cm from the edge of the glass sheet or the peripheral edge 128 of the grinding wheel 125. , 100cm, 125cm, 150cm, 200cm or up to 500cm.

Each cooling nozzle 171 can be adjusted in size and shape as needed to obtain a desired cooling effect. For example, the diameter of the opening of the cooling nozzle 171 may be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, 0.9mm, 1mm, 2mm, 3mm, 4mm, 5mm, or 10mm. Conventional polyvinyl chloride (PVC) or other plastic or metal pipes can be used for each of the coolant line 172 and the supply line. The cooling liquid may include water, cooling water, or other cooling liquids.

As described above, the apparatus and method described in this specification can be used to manufacture glass light guide plates. FIG. 14 illustrates an exemplary embodiment of a light guide plate 200 that can be manufactured by grinding and polishing edges to finish a glass sheet by the method and apparatus of the present disclosure. The glass sheet has a typical shape and structure of a light guide plate. The light guide plate includes a glass sheet having a first surface 210 and a second surface. The first surface 210 may be a front surface, and the second surface may be opposite to the first surface. The second surface may be It's the back. The first and second faces have a height H and a width W. In one or more embodiments, the first and / or second side has an average roughness (Ra) of less than 0.6 μm, 0.4 μm, or 0.2 μm, as measured by a 3D optical surface meter or surface topography device .

The glass sheet 200 has a thickness T between the front and back surfaces, where the thickness forms four edges. The thickness of the glass sheet is usually less than the height and width of the front and back. In various embodiments, the thickness of the light guide plate is less than 1.5% of the height of the front and / or the back. In one or more embodiments, the thickness T may be about 2mm, about 1.9mm, about 1.8mm, about 1.7mm, about 1.6mm, about 1.5mm, about 1.4mm, about 1.3mm, about 1.2mm, about 1.1 mm, about 1 mm, about 0.9 mm, about 0.8 mm, about 0.7 mm, about 0.6 mm, about 0.5 mm, about 0.4 mm, or about 0.3 mm. In some embodiments, the thickness T of the light guide plate is in a range of about 0.1 mm to about 2.5 mm, or in a range of about 0.2 mm to about 2 mm, or in a range of about 0.3 mm to about 1.5 mm. The height, width, and thickness of the light guide plate of some embodiments are configured and sized to be used as an LGP in LCD backlight applications.

In the illustrated embodiment, the first edge 230 is a light injection edge that receives light, for example, provided by one or more light emitting diodes (LEDs). In some embodiments, the light-injection edge scatters light in transmission at an angle of less than 12.8 degrees full-width half-maximum (FWHM). The light-injected edge may be obtained by grinding and polishing the first edge 230 according to the apparatus and method described in this specification.

The glass sheet further includes a second edge 240 and a third edge 260, the second edge 240 is adjacent to the first edge 230 (light injection edge), and the third edge 260 is opposite to the second edge 240 and adjacent to the light injection edge 230 , Wherein the second edge 240 and / or the third edge 260 scatter light in the reflection at an angle of less than 12.8 degrees full width half maximum (FWHM). The second edge 240 and / or the third edge 260 may include a diffusion angle of less than 6.4 degrees in the reflection. The glass sheet includes a fourth edge 250 opposite the first edge 230.

According to one or more embodiments, three of the four edges of the LGP have a mirror-polished surface for at least two reasons: LED coupling and total internal reflection (TIR) at both edges. According to one or more embodiments, and as shown in FIG. 15, light injected into the first edge 230 may be incident on a second edge 240 adjacent to the implanted edge and incident on a third edge 260 adjacent to the implanted edge, where the second edge 240 is opposite the third edge 260. The second and third edges may also include a low average roughness Ra (measured by an optical surface meter) of less than 0.5 micron, 0.4 micron, 0.3 micron, or 0.2 micron at the edge without etching with hydrofluoric acid and / or The slurry polishes the edges such that incident light undergoes total internal reflection from two edges adjacent to the first edge.

Light may be injected into the first edge 230 from an array of LEDs 300 positioned along the first edge 230. The LED may be located at a distance of less than 0.5 mm from the first edge 230. According to one or more embodiments, the LED may have a thickness or height that is less than or equal to the thickness of the glass sheet to provide effective light coupling to the light guide plate 200. According to one or more embodiments, the two edges 240, 260 may also include a diffusion angle of less than 6.4 degrees in the reflection.

Various modifications and changes can be made to the materials, methods, and articles described in this specification. In view of the description and implementation of the materials, methods, and articles disclosed in this specification, other aspects of the materials, methods, and articles described in this specification will be highlighted. It is understood that this specification and examples are to be considered exemplary. Obviously, those skilled in the art to which this invention pertains can make various improvements and changes without departing from the spirit or scope of this disclosure.

26‧‧‧ extension

30‧‧‧ glass

31‧‧‧first surface

32‧‧‧ second surface

33‧‧‧ end surface

41‧‧‧The first chamfer

42‧‧‧Second Chamfer

43‧‧‧ first edge

44‧‧‧ second edge

46‧‧‧Edge

47‧‧‧Edge

48‧‧‧ edge

49‧‧‧ edge

100‧‧‧ Equipment

110‧‧‧ support

110a, 110b ‧‧‧ support

116‧‧‧Workbench

117‧‧‧Clamping member

120‧‧‧First motor

121‧‧‧ First Spindle

122‧‧‧ rotation axis

125‧‧‧The first grinding wheel

125a, 125b ‧‧‧ grinding wheel

126‧‧‧ inside

127‧‧‧outside

128‧‧‧ peripheral edge

130‧‧‧second motor

131‧‧‧Second Spindle

132‧‧‧axis of rotation

135‧‧‧Second grinding wheel

135a, 135b‧‧‧grinding wheels

145‧‧‧controller

147‧‧‧First Force Transducer

148‧‧‧Second Force Transducer

170‧‧‧cooling system

171‧‧‧The first peripheral liquid cooling nozzle

172‧‧‧Liquid coolant line

200‧‧‧light guide

210‧‧‧ the first side

230‧‧‧ first edge

240‧‧‧ second edge

250‧‧‧ fourth edge

260‧‧‧ Third Edge

D _a ‧‧‧ distance

D _c ‧‧‧ distance

D _e ‧‧‧ distance

F1‧‧‧force

F2‧‧‧force

H‧‧‧ height

T _c1 ‧‧‧ thickness

T _c2 ‧‧‧ thickness

T _e ‧‧‧ thickness

T _g ‧‧‧total thickness

W‧‧‧Width

W _c1 ‧‧‧ Chamfer width

W _c2 ‧‧‧ Chamfering width

W _w1 ‧‧‧Width

W _w2 ‧‧‧Width

Ww2a‧‧‧Combination width

Ww2b‧‧‧Width

α‧‧‧first angle

β‧‧‧ second angle

δ1‧‧‧ Deflection

The accompanying drawings incorporated in and forming a part of this specification illustrate several embodiments described below.

FIG. 1A is a schematic diagram of a portion of a glass sheet according to one or more embodiments of the present disclosure; FIG.

1B and 1C are schematic views of a portion of a glass sheet after edge processing according to one or more embodiments of the present disclosure;

2 is a side view of an apparatus for finishing an edge of a glass sheet according to one or more embodiments, showing two grinding wheels positioned to grind the edge of the glass sheet;

FIG. 3 is a top view of a glass sheet showing two grinding wheels positioned to process the edge of the glass sheet according to one or more embodiments of the present disclosure; FIG.

4 is a perspective view of an apparatus for finishing an edge of a glass sheet according to one or more embodiments, showing two grinding wheels in a position for processing the edge of the glass sheet;

5 shows a side view of a grinding wheel on a main shaft according to one or more embodiments;

6A shows a side view of a grinding wheel of an edge processing apparatus in a grinding position according to one or more embodiments;

6B shows a side view of a grinding wheel of an edge processing apparatus according to one or more embodiments, in a position where the grinding wheel is changed;

Fig. 7 is a partial side view of the glass sheet, showing the edge of the glass sheet being polished by a grinding wheel.

8 is a cross-sectional view of a glass sheet including a portion extending from a fixing device and showing a deflection that occurs when a force is applied to an end of the glass sheet;

FIG. 9 shows a schematic diagram of a portion of an edge finishing apparatus according to one or more embodiments of the present disclosure;

FIG. 10 shows a schematic diagram of a portion of an edge finishing apparatus according to one or more embodiments of the present disclosure;

11 shows a schematic diagram of a portion of an edge finishing apparatus according to one or more embodiments of the present disclosure;

FIG. 12 shows a schematic diagram of an edge finishing apparatus according to one or more embodiments of the present disclosure;

13 is a partial perspective view of a grinding wheel having a cooling system according to one or more embodiments;

FIG. 14 illustrates an exemplary embodiment of a light guide plate; and

FIG. 15 illustrates total internal reflection of light at two adjacent edges of a glass light guide plate.

Domestic hosting information (please note in order of hosting institution, date, and number) None

Information on foreign deposits (please note in order of deposit country, institution, date, and number) None

Claims (20)

An apparatus for finishing an edge of a glass sheet, the apparatus comprising: a table supporting the glass sheet when the edges are subjected to grinding and polishing, wherein an X axis is on the table A lateral movement direction on a plane of a glass sheet, a Y axis is a longitudinal movement direction on the plane perpendicular to the X axis, and a Z axis is an orthogonal movement direction with respect to the plane; A first motor having a first main shaft, the first motor being positioned on a first side of the plane, the first main shaft having a first main axis of rotation, the first main axis being substantially along the X-axis alignment; a second motor having a second main shaft, the second motor being positioned on a second side of the plane, the second main shaft having a second rotating main shaft axis, the second main shaft The axis is substantially aligned along the X-axis; a first grinding wheel is mounted on the first main shaft, the first grinding wheel is a substantially dish-like shape with a peripheral edge to use the first grinding wheel The peripheral edge makes a part of the glass sheet The first edge becomes a chamfer; and a second grinding wheel is mounted on the second main shaft, the second grinding wheel is a substantially dish-like shape with a peripheral edge to use the second The peripheral edge of the grinding wheel chamfers a second edge of the glass sheet. The apparatus according to claim 1, wherein one or more of the first main shaft or the second main shaft further includes an additional grinding wheel. The apparatus of claim 1, wherein the first and second spindles are configured to produce a chamfer that is less than or equal to about 5% of a thickness of the glass sheet. The apparatus according to claim 1, wherein each of the first grinding wheel and the second grinding wheel independently has an average particle size in a range of about 200 μm to about 3 μm. The apparatus according to claim 1, wherein the first grinding wheel and the second grinding wheel are compliant urethane-based wheels. The device according to claim 1, wherein an interval between the first spindle and the second spindle is greater than or equal to a radius of the first grinding wheel or the second grinding wheel plus 10 mm. The device according to claim 1, wherein each of the first motor and the second motor is movable on the Z axis by a distance equal to or greater than 60 mm from the table. The apparatus according to claim 1, wherein the table is configured to move the glass sheet on a plane formed by the X-axis and the Y-axis adjacent to the first grinding wheel and the second grinding wheel. The apparatus of claim 8, wherein the table is configured to move the glass sheet at a rate in a range of about 5 m / min to about 30 m / min. The apparatus of claim 1, wherein each of the first grinding wheel and the second grinding wheel has a thickness sufficient to provide a contact greater than or equal to about 25 mm. The apparatus according to claim 1, wherein the first motor and the second motor are pushed toward the table. The apparatus according to claim 11, further comprising one or more of an air bearing or a force transducer coupled to the first motor and the second motor. The apparatus of claim 1, wherein the first motor and the second motor are configured to operate at a speed in a range of about 600 rpm to about 3000 rpm. The device according to claim 1, further comprising a plurality of first peripheral liquid cooling nozzles and a plurality of second peripheral liquid cooling nozzles, the plurality of first peripheral liquid cooling nozzles being adjacent to the first main shaft and positioned to cool The liquid is guided toward the peripheral edge of the first grinding wheel, and the plurality of second peripheral liquid cooling nozzles are adjacent to the second main shaft and positioned to guide the cooling liquid toward the peripheral edge of the second grinding wheel. The device according to claim 1, further comprising a plurality of remote liquid cooling nozzles, the plurality of remote liquid cooling nozzles being located at the distal ends of the first grinding wheel and the second grinding wheel and positioned to direct the cooling liquid toward the One edge of the glass sheet guides. A method for finishing an edge of a glass sheet includes the following steps: a glass sheet is supported on a workbench, a part of the glass sheet extends a distance from the workbench, and the glass sheet includes a first surface A second surface and an end surface, the second surface is opposite to the first surface, the first surface and the end surface intersect along a first edge and the second surface and the end surface intersect along a second edge, an X An axis is a lateral movement direction on a plane of a glass sheet on the surface, a Y axis is a longitudinal movement direction on the plane perpendicular to the X axis, and a Z axis is orthogonal to the plane A moving direction of the first edge of the first grinding wheel in contact with a peripheral edge of at least one first grinding wheel positioned on a first spindle axis of a first motor, the first grinding wheel being substantially dish-shaped; The two edges are in contact with a peripheral edge of at least one second grinding wheel positioned on a second spindle axis of a second motor, the second grinding wheel is substantially dish-shaped; and the first and second grinding wheels are respectively in contact with The first and second sides During the contact, relative movement between the first and the second grinding wheel and the glass, so that the first and second edges be chamfered. The method of claim 16, wherein the chamfer is less than or equal to about 5% of a thickness of the glass sheet. The method of claim 16, wherein the table is configured to move the glass sheet at a rate ranging from about 5 m / min to about 30 m / min. The method of claim 16, wherein each of the first grinding wheel and the second grinding wheel has a thickness sufficient to provide a contact greater than or equal to about 25 mm. The method of claim 16, further comprising providing a force to push the first motor and the second motor toward the table.