Embodiments are related to systems and methods for forming multi-tile display panels, and more particularly to systems and methods for forming display tiles having wrap-around edge electrodes.
Manufacturing of multi-tile displays often involves electrically connecting the display tiles and in some cases connecting electrical elements on one side of a display tile to electrical elements on the opposite side of the same display tile. Often such opposite side electrical connections are made using through-hole-vias, however, formation and use of such through-hole-vias can interfere with and/or damage electrical devices formed on a glass substrate. Use of wrap-around edge electrodes limits the need for problematic through-hole-vias. However, forming wrap-around edge electrodes to provide electrical interconnection is often difficult or unreliable where the display tile substrate is glass.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for manufacturing multi-tile displays.
Embodiments are related to systems and methods for forming multi-tile display panels, and more particularly to systems and methods for forming display tiles having wrap-around edge electrodes.
This summary provides only a general outline of some embodiments. The phrases “in one embodiment,” “according to one embodiment,” “in various embodiments”, “in one or more embodiments”, “in particular embodiments” and the like generally mean the particular feature, structure, or characteristic following the phrase is included in at least one embodiment, and may be included in more than one embodiment. Importa phrases do not necessarily refer to the same embodiment. Many other embodiments will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings.
A further understanding of the various embodiments of the present invention may be realized by reference to the figures which are described in remaining portions of the specification. In the figures, like reference numerals are used throughout several figures to refer to similar components. In some instances, a sub-label consisting of a lower case letter is associated with a reference numeral to denote one of multiple similar components. When reference is made to a reference numeral without specification to an existing sub-label, it is intended to refer to all such multiple similar components.
Embodiments are related to systems and methods for forming multi-tile display panels, and more particularly to systems and methods for forming display tiles having wrap-around edge electrodes.
In some cases, embodiments may be applied to yield edge geometries and surface quality on, for example, glass display tiles used in large screen, micro light emitting diode display (microLED display) arrays. The edge geometry and/or quality provided in some embodiments allow for formation of wrap-around electrodes used in connecting various electrical elements in the MicroLED display. As used herein, the phrase “electrical element” is used in its broadest sense to mean any device or structure capable of transferring and/or processing an electrical signal. Thus, an electrical element may be, but is not limited to, a conductor, a semiconductor, an electrode, a thin-film-transistor, a capacitor, a resistor, an inductor, a light emitting diode (hereinafter “LED”), an organic light emitting diode (hereinafter “OLED”), a liquid crystal cell, and/or an electrically controlled optical device. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of electrical elements that can be used in relation to different embodiments.
In some cases, the aforementioned edge geometry and/or quality is established after electrical elements are formed on a display tile very near an unfinished edge (i.e., a non-rounded edge) of the display tile. In various cases, the electrical elements are within five hundred (500) micrometers (hereinafter “microns”) of the unfinished edge of the display tile. In various cases, the electrical elements are within two hundred fifty (250) microns of the unfinished edge of the display tile. In some cases, the electrical elements are within one hundred fifty (150) microns of the unfinished edge of the display tile. In some cases, the electrical elements are within one hundred (100) microns of the unfinished edge of the display tile. In various cases, the electrical elements are within seventy (70) microns of the unfinished edge of the display tile. The aforementioned electrical elements may be formed on only one side of the display tile, or may be formed on both sides of the display tile.
Various embodiments provide for display tile formation. Such methods include: forming a series of perforation craters along a cut line on a surface of a panel where the panel includes an electrical element formed on the surface of the panel, and where the cut line is within two hundred, fifty (250) microns of the electrical element. The methods further includes separating one portion of the panel from another portion of the panel alon line to yield a display tile. In some instances of the aforementioned embodiments, the panel is a glass panel. In one or more instances of the aforementioned embodiments, the electrical element is a conductive trace.
In various instances of the aforementioned embodiments, the cut line is within one hundred (100) microns of the electrical element. In certain instances of the aforementioned embodiments, the cut line is a distance of less than or equal to sixty (60) microns of the electrical element. In some instances of the aforementioned embodiments, the cut line extends through the electrical element.
In some instances of the aforementioned embodiments, a maximum size of each of the perforation craters is less than forty (40) microns. In one or more instances of the aforementioned embodiments, a distance between two adjacent perforation craters is less than forty (40) microns. In certain instances of the aforementioned embodiments, the perforation craters are each formed by exposing the panel to laser energy. In various instances of the aforementioned embodiments, separating one portion of the panel from another portion of the panel along the cut line to yield the display tile includes mechanically breaking the panel along the cut line.
Some embodiments provide methods for display tile formation. Such methods include providing an edge processing system. The edge processing system includes: a display tile fixture, and a processing head. The display tile fixture is configured to hold a display tile in place during processing. An electrical element is formed on the display tile within two hundred, fifty (250) microns of an edge of the display tile. The processing head includes: a grinding wheel, a motor, and a movable arm. The grinding wheel includes a groove having a first width at an circumferential outer surface of the grinding wheel that is greater than a thickness of the edge of the display tile, and a second width within the groove that is less than the thickness of the edge of the display tile. As an example, in some cases where the display tile is made from Lotus NXT glass, the thickness of the edge of the display tile is 0.5 millimeters. The motor is coupled to the grinding wheel and configured to turn the grinding wheel. The methods further include: moving the movable arm such that the grinding wheel moves relative to the display tile fixture until the groove of the grinding wheel is over the edge of the display tile; and moving the movable arm such that the grinding wheel moves toward the edge of the display tile until opposing sides of the edge of the display tile contact the grinding wheel within the groove such that material from e opposing sides of the edge of the display tile is removed. The edge of the display tile is modified without contact between the grinding wheel and the electrical element.
Other embodiments provide edge processing systems that include: a display tile fixture, and a processing head. The display tile fixture is configured to hold a display tile in place during processing. An electrical element is formed on the display tile within two hundred, fifty (250) microns of an edge of the display tile. The processing head includes: a grinding wheel, a motor, and a movable arm. The grinding wheel includes a groove having a first width at a circumferential outer surface of the grinding wheel that is greater than a thickness of the edge of the display tile, and a second width within the groove that is less than the thickness of the edge of the display tile. The motor is coupled to the grinding wheel and configured to turn the grinding wheel. The methods further include:
In some instances of the aforementioned embodiments, the electrical element is formed on the display tile within one hundred (100) microns of the edge of the display tile. In various instances of the aforementioned embodiments, the electrical element is formed on the display tile within seventy (70) microns of the edge of the display tile. In some instances of the aforementioned embodiments, a profile of the groove results in a modification of the edge of the display tile that replaces an abrupt transition with a rounded transition. As used herein, an “abrupt transition” is any transition between adjoining surfaces and/or edges of a display tile where formation of a wrap-around electrode has more than a one percent possibility of a discontinuity. As one of many examples, an abrupt transition may be a sharp corner between a surface of the display tile and an edge of the display tile. In some such instances, the rounded edge exhibits a curve distance of less than two hundred (200) microns. In various such instances, the rounded edge exhibits a curve distance of less than one hundred (100) microns. In some such instances, the rounded edge exhibits a curve distance of less than sixty (60) microns.
In some instances of the aforementioned embodiments, the grinding wheel is a resin bonded grinding wheel having between twelve (12) volume percent and twenty (20) volume percent diamond abrasives, and the diamond abrasives are between two (2) microns and thirty-five (35) microns. in various instances of the aforementioned embodiments, the grinding wheel is a resin bonded grinding wheel having between twelve (12) volume percent and twenty (20) volume percent diamond abrasives, and the diamond abrasives are between three (3) microns and sixteen (16) microns. In some instances of the aforemention embodiments, the grinding wheel is a metal bonded grinding wheel having between twelve (12) volume percent and twenty (20) volume percent diamond abrasives, and wherein the diamond abrasives are between twelve (12) microns and thirty-two (32) microns. In some instances of the aforementioned embodiments, a depth of the groove is less than seventy (70) microns.
Yet other embodiments provide methods for making display tiles. The methods include: providing a display tile where the display tile has a glass substrate with at least one electrical element formed on the glass substrate within two hundred, fifty (250) microns of an edge of the display tile; mounting the display tile on a display tile fixture such that the edge of the glass substrate extends beyond an edge of the display tile fixture; providing a grinding wheel having a groove that exhibits a first width at a circumferential outer surface of the grinding wheel that is greater than a thickness of the edge of the display tile, and exhibits a second width below the circumferential outer surface of the grinding wheel where the second width is less than the thickness of the edge of the display tile; moving the grinding wheel relative to the display tile such that opposing sides of the edge of the display tile both extend into the groove and contact the grinding wheel below the circumferential outer surface of the grinding wheel; and further moving the grinding wheel toward the display tile such that material from each of the opposing sides of the edge of the display tile is removed. The edge of the display tile is modified without contact between the grinding wheel and the electrical element.
In some instances of the aforementioned embodiments, the grinding wheel has a distal end and a proximal end, and the groove is located a distance from the distal end; the display tile fixture has a height; and the distance is less than the height. In various cases, the edge of the glass substrate extends beyond an edge of the display tile fixture by a distance, and the distance is greater than a depth of the groove. In one case, the distance is between ten (10) microns and one thousand (1000) microns. In various cases, a profile of the groove results in a modification of the edge of the display tile that replaces an abrupt transition at the edge of the display profile with a rounded edge. In some cases, the at least one electrical element is a first electrical element formed on a first surface of the display tile, and the methods further include forming a wrap-around edge electrode extending from the first electrical element to a second electrical element formed on a second surface of the display tile, wherein the second surface is opposite the first surface.
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Electrical elements are formed on one or both surfaces of the glass panel (block 110). Where, for example, a display is to be manufactured, the electrical elements may include, but are not limited to, display elements such as LEDs, control circuits, and conductive traces. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of electrical elements that may be formed on the glass panel in accordance with different embodiments. Further, any processes known in the art for forming electrical elements on a glass panel may be used. For example, formation of the electrical elements may include, but is not limited to, placing electrical elements on the display panel, fluidically depositing electrical elements on the display panel, forming thin film transistors directly on the display panel, or depositing or printing metal traces directly on the display panel. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of processes that may be used to form electrical elements on the glass panel. Turning to
In some instances of the aforementioned embodiments, the electrical element is formed on the display tile within one hundred (100) microns of the edge of the display tile. In various instances of the aforementioned embodiments, the electrical element is formed on the display tile within seventy (70) microns of the edge of the display tile. In some instances of the aforementioned embodiments, a profile of the groove results in a modification of the edge of the display tile (as the edge of the display tile is contacted by the grinding wheel) that replaces an abrupt transition at the edge of the display profile with a rounded edge. In some such instances, the resulting rounded edge exhibits a curve distance of less than two hundred (200) microns. In various such instances, the rounded edge exhibits a curve distance of less than one hundred (100) microns. In some such instances, the rounded edge exhibits a curve distance of less than sixty (60) microns.
In some instances of the aforementioned embodiments, the grinding whe bonded grinding wheel having between twelve (12) volume percent and twenty (20) volume percent diamond abrasives, and the diamond abrasives are between two (2) microns and twenty (35) microns. In various instances of the aforementioned embodiments, the grinding wheel is a resin bonded grinding wheel having between twelve (12) volume percent and twenty (20) volume percent diamond abrasives, and the diamond abrasives are between three (3) microns and sixteen (16) microns. In some instances of the aforementioned embodiments, the grinding wheel is a metal bonded grinding wheel having between twelve (12) volume percent and twenty (20) volume percent diamond abrasives, and wherein the diamond abrasives are between twelve (12) microns and thirty-two (32) microns. In some instances of the aforementioned embodiments, a depth of the groove is less than seventy (70) microns.
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Using edge 210 shown in
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In accordance with various methods described herein, a display tile is secured to the edge processing system (block 125). In some cases, the display tile fixture includes a vacuum port connected to vacuum channels on a working surface of the display tile fixture. In such cases, securing the display tile to the edge processing system includes placing the display tile on the display tile fixture and engaging the vacuum to secure the two together. Placement of the display tile relative to the display tile fixture is important as the edge of the display tile to be processed must extend beyond the edge of the display tile fixture a sufficient distance to allow the edge to move into a groove on the grinding wheel sufficiently to finish processing the edge of the display tile without an outer edge of the grinding wheel contacting the display tile fixture. Further, the distance that the display tile extends beyond the display tile fixture is limited to reduce the amount of flex exhibited at the edge of the display tile during grinding. Limiting the flex at the edge of the display tile increases precision of the grinding process allowing for close proximity of electrical elements to the edge being processed. In some embodiments, the distance of the edge of the display tile from the edge of the display tile fixture is only slightly greater than the final contact depth within the groove of the grinding wheel. In some cases, the distance from the edge of the display tile fixture to the edge of the display tile is greater than ten (10) microns and less than one thousand (1000) microns, and the final contact depth of the groove in the grinding wheel is less than twenty-five (25) microns. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of final contact depths of the groove in the grinding wheel distance of the edge of the display tile from the edge of the display tile fixture that that may be used in relation to different embodiments.
With the display tile secured to the display tile fixture, the grinding wheel is aligned with the edge of the display tile to be processed (block 130). To assure edge processing is uniform on both sides of the edge of the display tile, the display tile is substantially centered within the groove on the grinding wheel.
An edge of the display tile is fed into the groove in the grinding wheel while maintaining alignment with the groove (block 135). In some embodiments, the feed rate of moving the groove of the grinding wheel along the edge of the display tile is five hundred millimeters per minute. In some cases a two step grind is performed to a defined depth using a rough grinding wheel with a feed rate of five hundred millimeters per minute along the edge of the display tile. The second grind step is performed using a fine grinding wheel using a feed rate of five hundred millimeters per minute across the edge of the display tile with the grind cutting is about seven (7) microns per pass (i.e., removing about seven (7) microns from the opposing sides of the edge of the display tile in a direction toward a center between the two edges on each pass). Based upon the disclosure provided herein, one of ordinary skill in the art will recognize other feed rates and cut depths that may be used in relation to different embodiments. The grinding process may continue to a depth into the groove that yields a fully rounded edge on the display tile, or continues only to a point that yields a desired chamfered edge with a straight face. Where the edge is fully rounded, the curve distance of the edge is in the range of one (1) to five hundred (500) microns. In some embodiments, the curve distance of the edge is in the range of one (1) to two hundred (200) microns. In various embodiments, the curve distance of the edge is in the range of one (1) to one hundred (100) microns. In some embodiments, the curve distance of the edge is in the range of one (1) to fifty (50) microns.
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In some embodiments, two different grinding wheels 310 are used in series. A first grinding wheel 310 is a metal bonded abrasive grinding wheel used to perform a roughing process. In this roughing process, the rotational velocity of grinding wheel 310 is forty thousand (40,000) revolutions per minute, the surface feet per minute of the outer perimeter of grinding wheel 310 is between four thousand five hundred ninety-one (4591) and five thousand two hundred ten (5210), the feed rate of the edge being processed into groove 316 is five hundred millimeters per minute, and the depth of the cut (per pass) is fifty (50) microns.
Turning to
Returning to
Turning to
A vacuum channel 349 is open at working surface 354 and extends into working surface 354. For example, vacuum channel 349 is open around a periphery of working surface 354 and across working surface 354. Vacuum channel 349 is connected to a vacuum source opening 346. A number of mounting screws 348 extend from below working surface 354 though display tile fixture 340, and operate to securely attach display tile fixture 340 to a mounting plate (not shown). A corner 352 of display tile fixture 340 is shown for orientation purposes.
In operation, a vacuum source (not shown) is attached to a vacuum source opening 346 via the non-working side of display tile fixture 340. The vacuum source is engaged causing a vacuum pressure to exist at vacuum source opening 346 near working surface 354. When a display panel tile (not shown) is placed on working surface 354 of display tile fixture 340, the display panel tile is held securely in place by the vacuum pressure from vacuum source opening 346 and extending through vacuum channel 349.
The precision of an edge modification made to a display tile mounted to fixture 340 is limited by the flatness of working surface 354 on which the display tile rests. To assure a desired flatness, working surface 354 is diamond turned resulting in a reduction of the height of surface anomalies extending from a desired plane of working surface 354. Diamond turning is done by spinning display fixture 340 on a lathe relative to a diamond tipped tool that removes any surface anomalies protruding from working surface 354. An example of non-flatness is demonstrated in
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In some embodiments, grinding wheel 310 is a resin bonded grinding wheel. A resin bonded grinding wheel provides more dampening than other types of grinding wheels, such as, for example, electroplated grinding wheels. Such dampening, among other things, reduces the size and volume of conchoidal fractures occurring during edge processing. In other embodiments, grinding wheel 310 is an electroplated grinding wheel. In some embodiments, a set of two grinding wheels is used. The first grinding wheel in the set is used for rough grinding. This first grinding wheel is a resin bonded grinding wheel including integrated diamond abrasives in the size of fifteen (15) to thirty (30) microns with a volume percent of diamond abrasive in the range of 12.5 to 18.75 volume percent. The second grinding wheel in the set is used for fine grinding. This second grinding wheel is coated, resin bonded grinding wheel including integrated diamond abrasives in the size of four (4) to fifteen (15) microns, with a volume percent of diamond abrasive in the range of 12.5 to thirty (30) percent. In some cases, the volume percent of diamond abrasive is in the range of 12.5 to twenty-five (25) percent. In various cases, volume percent of diamond abrasive in the range of 12.5 to 18.75 percent. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize other grinding wheels and implementations thereof that may be used in relation to different embodiments. For example, grinding wheel 310 may be, but is not limited to, single layer, electroplated wheels and abrasive belts (e.g., a single layer Trizact). Any abrasive component capable of being formed with precision and positioned accurately with respect to the tile may be used.
Where the side edges of display panel 350 are to be finished, width 364 is greater than width 358 by a sufficient amount to allow grinding wheel grove 316 to encompass the edge without contact between distal end 312 of grinding wheel 310 and display tile fixture 340. As such, distance 342 is greater than a final contact depth within groove 316. Further, distance 342 is limited to reduce the amount of flex exhibited at the edge of display tile 350 being processed. As such, distance 342 is only slightly greater than the final contact depth within groove 316. In some cases, distance 342 is less than one thousand (1000) microns and greater than ten (10) microns, and the final contact depth of groove 316 is less than fifteen (15) microns. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of final contact depths of groove 316 and distances 342 that may be used in relation to different embodiments.
Additionally, to allow the edge of display tile 350 to slide inside groove 316 to an initial contact depth within groove 316 and then on to the final contact depth within groove 316, width 322 is larger than height 368. In some cases, width 322 is less than 1.5 millimeters and greater than 0.5 millimeters, and height 368 of display panel 350 is less than 1.3 millimeters and greater than 0.3 millimeters. Further, to allow grinding wheel 310 to pass freely along an edge of display tile 350, height 344 is greater than distance 320 when a block onto which display plate fixture 344 is mounted extends beyond the edges of display plate fixture 344.
Geometry of groove 316 of grinding wheel 310 is designed to accommodate a specific glass display tile thickness. Such geometry and display tile thickness determines the point of initial contact between sides of the display tile edge being processed and In addition, such geometry and display tile thickness in addition to a depth into groove 316 that a display tile is fed determines the amount of material removed from the periphery of the display tile and the chamfer depth on the finished product. As such, the accuracy of the geometry of groove 316 and the alignment of groove 316 to the display tile is controlled. In some cases, control of the aforementioned alignment is within fifteen (15) microns in any direction in a plane perpendicular to the large surfaces of the display tile.
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Edge processing system 300 further includes a processing head 301 that is movable relative to display tile 350 fixed on display tile fixture 340. Processing head 301 includes a motor 386 capable of rotating a securing element 384. Proximal end 314 of grinding wheel 310 is held securely in place by securing element 384 such that it rotates at the same speed as securing element 384. Processing head 301 further includes a cooling liquid tube 382 and a cooling liquid nozzle 380. During edge processing of display tile 350, a cooling liquid is passed through cooling liquid tube 382 and cooling liquid nozzle 380 and onto the interface of groove 316 in grinding wheel 310 to reduce any chipping and deformation of display tile 350. Processing head 301 is attached to a precision movement control (not shown) by an arm 388 allowing precise movement in three dimensions of groove 316 relative to the edge of display tile 350 being processed.
In operation, motor 386 is engaged such that grinding wheel 310 spins at a defined speed. Arm 388 is moved to slide groove 316 of grinding wheel over the edge of display tile 350 to be processed. Groove 316 is moved precisely relative to the processed edge such that both sides of the edge of display tile 350 contact a side of groove at an initial groove contact.
Processing continues by slowly pressing groove 316 further onto the edge of display tile 350 until it reaches a final groove contact 438 shown in
Selection of grinding process kinematics (rotational velocity of grinding wheel 310, feed rate of groove 316 over the edge of display tile 350, depth of final groove contact 438 into groove 316, feed rate of the edge being processed into groove 316, and/or rotational direction of grinding wheel 310 relative to the edge of display tile 350) and the composition of grinding wheel 310 (bond matrix material, secondary abrasive, primary diamond abrasive size, and fracture toughness) enables reduction in the size of the conchoidal fractures or chips at the edge-to-surface transition (e.g., from side 210 to surface 272 as shown in
In some embodiments, two different grinding wheels 310 are used in series. A first grinding wheel 310 is a metal bonded abrasive grinding wheel used to perform a roughing process. In this roughing process, the rotational velocity of grinding wheel 310 is thousand (40,000) revolutions per minute, the surface feet per minute of the outer perimeter of grinding wheel 310 is between four thousand five hundred ninety-one (4591) and five thousand two hundred ten (5210), the feed rate of the edge being processed into groove 316 is five hundred millimeters per minute, and the depth of the cut (per pass) is fifty (50) microns.
A second grinding wheel 310 is a resin bonded grinding wheel that is used to perform a finishing process. In this finishing process, the rotational velocity of grinding wheel 310 is forty thousand (40,000) revolutions per minute, the surface feet per minute of the outer perimeter of grinding wheel 310 is between four thousand five hundred ninety-one (4591) and five thousand two hundred ten (5210), the feed rate of the edge being processed into groove 316 is five hundred millimeters per minute, and the depth of the cut (per pass) is seven (7) microns. It should be noted that the aforementioned grinding process kinematics are used in one embodiment, and that based upon the disclosure provided herein, one of ordinary skill in the art will recognize other kinematics that may be used based upon the particular result desired.
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A region 520 is shown surrounded by an oval shaped dashed line. As shown in
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The location of the cut line to which the laser is aligned is exposed to las such that a material characteristic of the panel is changed around the location (block 576). In some embodiments, the change in the material characteristic is a change in a refractive index of the panel at the location which results in a weakening of the material at that location. In various embodiments, to create a uniform edge along the cut line the focal line of the laser energy is longer than the thickness of the panel being cut, such that a uniform crack was generated throughout the panel. As an alternative embodiment, the electrical elements on the panel may be formed such that they extend beyond the cut line and thereby will be directly exposed to the laser energy. In such embodiments, the electrical element is partially ablated during the exposure to the laser energy, and absorbs a significant portion of the laser energy. This absorption may result in a non-uniformity along the edge that can be corrected using a mechanical or chemical edge polishing step before forming side electrodes over the edge. Examples of such non-uniformity are discussed below in relation to
It is determined whether the cut line has been finished (block 578). Where the cut line has not been finished, the laser is aligned with a next location along the defined cut line (block 580) and the exposure process (block 576) is repeated for the next location. This process continues making a series of exposures along the cut line until the cut line has been completed (block 578). The series of exposures result in a perforation like changes in the material characteristic of the panel along the cut line.
Turning to
Stress cracks 591 occur due to application of laser energy to laser exposure craters 590. Ideally, as shown in
Other problems can occur where too much laser energy (either in magnitude or exposure time) is applied in a unit area to one or more of craters 590.
Yet other problems can occur where the energy from the laser is too low (either in magnitude or exposure time) as it fails to generate sufficient energy to cause stress cracks 591. An example of this is shown in
The effects of laser energy directed at the series of laser exposure perforation craters 590 along cut line 510 varies depending upon whether the surface of the panel impacted by the laser energy includes electrical elements either disposed over or near the laser exposure craters 590. In particular, the numerical aperture and length of a Bessel beam (i.e., a Gaussian beam is directed through an axicon where the axicon is focused at a further distance in the direction of propagation, such that a focal line, rather than a point, is formed varied such that the cut lines can be close to electrical elements on the surface of the panel without damaging such electrical elements or affecting the edge uniformity after separation. Any objects on the surface of the panel (e.g., electrical elements) which absorb, reflect, scatter, or otherwise perturb the wavelength of light at which the laser is operating or the coherence of the beam can pose a challenge to the process of changing the material characteristic of the panel by exposure to the laser energy. In some embodiments, to cut near conductive traces on the surface of the panel, a one thousand sixty-four (1064) nanometer Bessel beam is generated that exhibits an approximately 1.7 millimeter full-width at half-maximum (FWHM) line length with a numerical aperture (NA) of 0.27. Such a geometry has been found effective for cutting as close as sixty (60) microns away from a conductive trace on the surface of the panel while maintaining a uniform edge. Decreasing the NA further (i.e., decreasing the cone angle of the Bessel beam), would allow the cut line to be even closer to the electrical elements without shadowing effects. In some cases, cuts within thirty (30) microns of a conductive trace on the surface of the panel are possible without shadowing effects where additional controls such as, for example, decreasing the NA in accordance with some embodiments. Such a modification, however, would increase the diameter of the cone of light which forms the focal line. In some cases, this causes a wider ablation zone at the surface (i.e., increases the size of craters 590). Therefore, there needs to be a balance between cutting proximity to tile edges, damage to electrical components on the surface of the panel, and/or cutting effectiveness.
As cutting gets closer to electrical elements or even cuts through electrical elements, shadowing effects start to become more prominent. Turning to
As shown, two different types of electrical elements 550, 555 are shown near cut line 510. In particular, electrical elements 555 are conductive traces on surface 502 of the panel that extend into or beyond cut line 510, and electrical elements 550 are conductive traces on surface 502 of the panel are near but do not extend into or beyond cut line 510. More particularly, electrical elements 555a extend a distance (Doverlap,a) beyond cut line 510, electrical elements 555b extend a distance (Doverlap,b) beyond cut line 510, electrical elements 550b extend a distance extend a distance (Daway,b) from cut line 510, at elements 550a extend a distance extend a distance (Daway,a) from cut line 510. In one certain case, Doverlap,a is one hundred (100) microns, Doverlap,b is thirty (30) microns, Daway,b is thirty (30) microns, and Daway,a is sixty (60) microns.
As shown in side perspective view 503, each of the electrical elements 550, 555 have a different impact on how laser exposure along cut line 510 effects surface 506. In particular, electrical elements 555a that extend a significant distance beyond cut line 510 result in substantial interference with the laser energy such that large areas (i.e., areas 508, 514) under and in some cases beyond electrical elements 555a are unchanged. In contrast, electrical elements 555b that extend a smaller distance beyond cut line 510 result in less substantial interference with the laser energy such that smaller areas (i.e., areas 516, 518) under and in some cases beyond electrical elements 555b are unchanged. Electrical elements 550b that extend close to cut line 510 result in interference with the laser energy such that areas (i.e., areas 522, 524) beyond electrical elements 550b are unchanged. Electrical elements 550a that do not extend close to cut line 510 do not result in interference with the laser energy such that an area 526 beyond electrical elements 550a is unchanged. Failure to change the characteristic of the material at areas 508, 514, 516, 518, 522, 524 decreases strength in the panel at areas along cut line 510, and can result in a ragged break leaving surface anomalies that are difficult to cover with electrical elements, such as, for example, side electrodes. In some embodiments, the failure to change the characteristic of the material at areas 508, 514, 516, 518, 522, 524 does not result in a ragged edge upon snapping the panel at cut line 510, but can leave areas where the difference in material characteristics make it difficult to cover with electrical elements, such as, for example, side electrodes.
Alternatively, the beam or panel could be placed at an angle relative to one another, such that the angle between the cone of the beam with respect to the center of the tile to be singulated is greater than if the beam were perpendicular to the panel. The position of the focal line could also be raised above the middle of the panel in order to minimize any damage to the electrodes on the laser exit side.
Returning to
Some embodiments provided herein yield display tiles exhibiting a uniform edge that does not have sharp or abrupt features; minimal damage/defects on top, bottom and/or side surfaces; and/or cut lines and/or polish lines that are very near electrical elements such as, for example, conductive traces on one or more surfaces of the display tiles. Such approaches may allow for minimization or elimination of damage to electrical elements on one or more surfaces of the display tiles. Further, such approaches may reduce the occurrence of discontinuities in side electrodes, and/or allow for thin side electrodes that allow for reducing the distance between individual display tiles in a multi-tile display.
In conclusion, various novel systems, devices, methods and arrangements for direct edge finished displays are discussed herein. While detailed descriptions of one or more embodiments have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.
This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/741,174 filed on Oct. 4, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/053938 | 10/1/2019 | WO | 00 |
Number | Date | Country | |
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62741174 | Oct 2018 | US |