WO2020060773A1

WO2020060773A1 - Alignment fixtures for aligning glass stacks and methods of ceramming glass stacks

Info

Publication number: WO2020060773A1
Application number: PCT/US2019/049877
Authority: WO
Inventors: Jill Marie HALL; William Jason HILL; JR. John Robert SALTZER; John David SCHRAMM; Michael Aaron ZAHRADKA; Christine Marie ZIEGENFUS
Original assignee: Corning Incorporated
Priority date: 2018-09-19
Filing date: 2019-09-06
Publication date: 2020-03-26

Abstract

An alignment fixture for aligning glass sheets within a glass stack includes a longitudinal portion defining a longitudinal glass engagement face oriented to face in a lateral direction, and a longitudinal setter engagement face oriented to face in the lateral direction, where the longitudinal setter engagement face is spaced apart from the longitudinal glass engagement face, a lateral portion defining a lateral glass engagement face oriented to face in the longitudinal direction, and a lateral setter engagement face oriented to face in the longitudinal direction, where the lateral setter engagement face is spaced apart from the lateral glass engagement face, and a comer aperture extending through the alignment fixture in a vertical direction, where the comer aperture defines an aperture face that is spaced apart from a glass sheet envelope defined by the longitudinal glass engagement face and the lateral glass engagement face.

Description

ALIGNMENT FIXTURES FOR ALIGNING GLASS STACKS

AND METHODS OF CERAMMING GLASS STACKS

BACKGROUND

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 62/733220 filed on September 19, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD

[0002] The present specification generally relates to methods and apparatus for ceramming glass sheets and, more particularly, to alignment fixtures for use in ceramming glass sheets.

TECHNICAL BACKGROUND

[0003] There continues to be a demand for high strength glass that can be used in portable electronic devices. Several materials are currently being used as covers for portable electronic devices, such as glass, zirconia, plastics, metals, and glass-ceramics. Benefits of using glass- ceramics include high strength and high transmissivity, which make glass-ceramics a good choice for optical displays and for electromagnetic charging.

[0004] However, forming glass-ceramics can be difficult, particularly when trying to obtain high throughputs during the ceramming process. For example, forming glass-ceramics requires precise control of the thermal profile of glass articles during the ceramming process, which becomes difficult when glass articles are stacked in a heating apparatus, such as, for example, a lehr.

[0005] Accordingly, a need exists for alternative methods and apparatuses for producing glass ceramic sheets having a high optical quality.

SUMMARY

[0006] In one embodiment, an alignment fixture for aligning glass sheets within a glass stack includes a longitudinal portion extending in a longitudinal direction, the longitudinal portion defining a longitudinal glass engagement face oriented to face in a lateral direction that is transverse to the longitudinal direction, and a longitudinal setter engagement face oriented to face in the lateral direction, where the longitudinal setter engagement face is spaced apart from the longitudinal glass engagement face, a lateral portion extending in the lateral direction, the lateral portion defining a lateral glass engagement face oriented to face in the longitudinal direction, and a lateral setter engagement face oriented to face in the longitudinal direction, where the lateral setter engagement face is spaced apart from the lateral glass engagement face, and a corner aperture extending through the alignment fixture in a vertical direction that is transverse to the longitudinal direction and the lateral direction, where the corner aperture defines an aperture face that is spaced apart from a glass sheet envelope defined by the longitudinal glass engagement face and the lateral glass engagement face.

[0007] In another embodiment, a method for ceramming a glass stack includes positioning a setter plate on a carrier plate, engaging adjacent setter plate edges of the setter plate with a lateral portion and a longitudinal portion of an alignment fixture that extends in a longitudinal direction transverse to the lateral portion of the alignment fixture, engaging adjacent glass edges of a glass sheet with the lateral portion and the longitudinal portion of the alignment fixture, positioning the glass sheet on the setter plate, and heating the carrier plate, the setter plate, and the glass sheet above an annealing point of the glass sheet.

[0008] In yet another embodiment, a method for ceramming a glass stack includes positioning a setter plate on a carrier plate, engaging adjacent setter plate edges of the setter plate with a lateral setter engagement face and a longitudinal setter engagement face of an alignment fixture, where the lateral setter engagement face is oriented transverse to the longitudinal setter engagement face, engaging adjacent glass edges of a glass sheet with a lateral glass engagement face and a longitudinal glass engagement face of the alignment fixture, where the lateral glass engagement face is aligned with and spaced apart from the lateral setter engagement face in a longitudinal direction and where the longitudinal glass engagement face is aligned with and spaced apart from the longitudinal setter engagement face in a lateral direction, positioning a corner of the glass sheet within a corner aperture extending through the alignment fixture in a vertical direction that is transverse to the longitudinal direction and the lateral direction, where the comer aperture defines an aperture face that is spaced apart the comer of the glass sheet, positioning the glass sheet on the setter plate, and heating the carrier plate, the setter plate, and the glass sheet above an annealing point of the glass sheet.

[0009] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings. The various features discussed in the disclosure may be used in any and all combinations, for example as set forth in the following embodiments.

[0010] Embodiment 1. An alignment fixture for aligning glass sheets within a glass stack, the alignment fixture comprising:

a longitudinal portion extending in a longitudinal direction, the longitudinal portion defining:

a longitudinal glass engagement face oriented to face in a lateral direction that is transverse to the longitudinal direction; and

a longitudinal setter engagement face oriented to face in the lateral direction, wherein the longitudinal setter engagement face is spaced apart from the longitudinal glass engagement face;

a lateral portion extending in the lateral direction, the lateral portion defining:

a lateral glass engagement face oriented to face in the longitudinal direction; and a lateral setter engagement face oriented to face in the longitudinal direction, wherein the lateral setter engagement face is spaced apart from the lateral glass engagement face; and

a comer aperture extending through the alignment fixture in a vertical direction that is transverse to the longitudinal direction and the lateral direction, wherein the comer aperture defines an aperture face that is spaced apart from a glass sheet envelope defined by the longitudinal glass engagement face and the lateral glass engagement face.

[0011] Embodiment 2. The alignment fixture of Embodiment 1, wherein the aperture face is spaced apart from a setter plate envelope defined by the longitudinal setter engagement face and the lateral setter engagement face.

[0012] Embodiment 3. The alignment fixture of Embodiment 1 or Embodiment 2, wherein the longitudinal portion further comprises a longitudinal outer face, and a distance evaluated between the longitudinal outer face and the longitudinal setter engagement face is 15 millimeters.

[0013] Embodiment 4. The alignment fixture of any one of Embodiments 1-3, wherein the lateral portion further comprises a lateral outer face, and a distance evaluated between the lateral outer face and the lateral setter engagement face is 25 millimeters.

[0014] Embodiment 5. The alignment fixture of any one of Embodiments 1-4, further comprising a swing arm pivotally coupled to the longitudinal portion opposite the lateral portion.

[0015] Embodiment 6. The alignment fixture of Embodiment 5, wherein the swing arm defines a glass engagement face, and wherein the swing arm is repositionable between a disengaged position, in which the glass engagement face is positioned outside of the glass sheet envelope, and an engaged position, in which the swing arm is positioned within the glass sheet envelope.

[0016] Embodiment 7. The alignment fixture of any one of Embodiments 1-6, further comprising a carrier pin assembly coupled to one of the longitudinal portion and the lateral portion, the carrier pin assembly comprising a carrier pin extending outward from the longitudinal portion or the lateral portion in the vertical direction.

[0017] Embodiment 8. The alignment fixture of Embodiment 7, further comprising a biasing member coupled to the carrier pin assembly.

[0018] Embodiment 9. A method for ceramming a glass stack, the method comprising:

positioning a setter plate on a carrier plate;

engaging adjacent setter plate edges of the setter plate with a lateral portion and a longitudinal portion of an alignment fixture that extends in a longitudinal direction transverse to the lateral portion of the alignment fixture;

engaging adjacent glass edges of a glass sheet with the lateral portion and the longitudinal portion of the alignment fixture;

positioning the glass sheet on the setter plate; and

heating the carrier plate, the setter plate, and the glass sheet above an annealing point of the glass sheet.

[0019] Embodiment 10. The method of Embodiment 9, wherein the glass sheet is a first glass sheet, and wherein the method further comprises:

engaging adjacent glass edges of a second glass sheet with the lateral portion and the longitudinal portion of the alignment fixture; and positioning the second glass sheet on the first glass sheet.

[0020] Embodiment 11. The method of Embodiment 10, wherein:

the adjacent glass edges of the first glass sheet comprise a longitudinal glass edge and a lateral glass edge;

the adjacent glass edges of the second glass sheet comprise a longitudinal glass edge and a lateral glass edge; and

engaging the adjacent glass edges of the second glass sheet with the lateral portion and the longitudinal portion of the alignment fixture comprises aligning the longitudinal glass edge of the second glass sheet with the longitudinal glass edge of the first glass sheet, such that an overhang distance evaluated between the longitudinal glass edge of the second glass sheet and the longitudinal glass edge of the first glass sheet is less than 2 millimeters.

[0021] Embodiment 12. The method of any one of Embodiments 9-11, further comprising:

rotating a swing arm pivotally coupled to the longitudinal portion;

engaging the swing arm with a glass edge of the glass sheet; and

moving the glass sheet against a lateral glass engagement face of the lateral portion with the swing arm.

[0022] Embodiment 13. The method of any one of Embodiments 9-12, further comprising:

rotating a swing arm pivotally coupled to the longitudinal portion;

engaging the swing arm with a setter plate edge of the setter plate; and

moving the setter plate against a lateral setter engagement face of the lateral portion with the swing arm.

[0023] Embodiment 14. The method of any one of Embodiments 9-13, further comprising inserting a carrier pin coupled to the alignment fixture into an aperture of the carrier plate.

[0024] Embodiment 15. The method of Embodiment 14, further comprising, prior to heating the carrier plate, rotating the carrier pin with respect to the carrier plate, moving the carrier pin outside of the aperture of the carrier plate.

[0025] Embodiment 16. The method of any one of Embodiments 9-15, wherein the alignment fixture is a first alignment fixture, and the method further comprises engaging adjacent glass edges of the glass sheet with a lateral portion and a longitudinal portion of a second alignment fixture positioned opposite the first alignment fixture.

[0026] Embodiment 17. The method of any one of Embodiments 9-16, wherein the setter plate is a first setter plate, and wherein the method further comprises: positioning a second setter plate on the carrier plate, spaced apart from the first setter plate; and

engaging adjacent setter plate edges of the first setter plate with the lateral portion and the longitudinal portion of the alignment fixture while engaging an outer face of the alignment fixture with a setter plate edge of the second setter plate.

[0027] Embodiment 18. A method for ceramming a glass stack, the method comprising:

positioning a setter plate on a carrier plate;

engaging adjacent setter plate edges of the setter plate with a lateral setter engagement face and a longitudinal setter engagement face of an alignment fixture, wherein the lateral setter engagement face is oriented transverse to the longitudinal setter engagement face;

engaging adjacent glass edges of a glass sheet with a lateral glass engagement face and a longitudinal glass engagement face of the alignment fixture, wherein the lateral glass engagement face is aligned with and spaced apart from the lateral setter engagement face in a longitudinal direction and wherein the longitudinal glass engagement face is aligned with and spaced apart from the longitudinal setter engagement face in a lateral direction;

positioning a comer of the glass sheet within a corner aperture extending through the alignment fixture in a vertical direction that is transverse to the longitudinal direction and the lateral direction, wherein the comer aperture defines an aperture face that is spaced apart the corner of the glass sheet;

positioning the glass sheet on the setter plate; and

[0028] Embodiment 19. The method of Embodiment 18, wherein the glass sheet is a first glass sheet, and wherein the method further comprises:

engaging adjacent glass edges of a second glass sheet with the lateral glass engagement face and the longitudinal glass engagement face of the alignment fixture; and positioning the second glass sheet on the first glass sheet.

[0029] Embodiment 20. The method of Embodiment 18 or Embodiment 19, wherein the setter plate is a first setter plate, and wherein the method further comprises:

positioning a second setter plate on the carrier plate, spaced apart from the first setter plate; and engaging adjacent setter plate edges of the first setter plate with the lateral setter engagement face and the longitudinal setter engagement face of the alignment fixture while engaging an outer face of the alignment fixture with a setter plate edge of the second setter plate.

[0030] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments of alignment fixtures and methods for ceramming a glass sheet and are intended to provide an overview or framework for understanding the nature and character of the Embodimented subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the Embodimented subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1A schematically depicts a side view of a glass stack positioned on a setter plate and a carrier plate, according to one or more embodiments shown and described herein;

[0032] FIG. 1B schematically depicts a side view of a glass stack including intervening setter plates, according to one or more embodiments shown and described herein;

[0033] FIG. 2 schematically depicts a perspective view of a carrier plate in isolation, according to one or more embodiments shown and described herein;

[0034] FIG. 3 schematically depicts a perspective view of another carrier plate in isolation, according to one or more embodiments shown and described herein;

[0035] FIG. 4 schematically depicts a top view of multiple glass stacks positioned on setter plates and a carrier plate, according to one or more embodiments shown and described herein;

[0036] FIG. 5 schematically depicts an enlarged view of adjacent glass sheets of the glass stack of FIG. 1 A, according to one or more embodiments shown and described herein; [0037] FIG. 6A schematically depicts a top view of an alignment fixture, according to one or more embodiments shown and described herein;

[0038] FIG. 6B schematically depicts a section view of the alignment fixture of FIG. 6A along section 6B-6B, according to one or more embodiments shown and described herein;

[0039] FIG. 6C schematically depicts a section view of the alignment fixture of FIG. 6A along section 6C-6C, according to one or more embodiments shown and described herein;

[0040] FIG. 7 schematically depicts alignment fixtures of FIG. 6 A positioned on a carrier plate, according to one or more embodiments shown and described herein;

[0041] FIG. 8A schematically depicts a perspective view of another alignment fixture, according to one or more embodiments shown and described herein;

[0042] FIG. 8B schematically depicts a top view of the alignment fixture of FIG. 8A, according to one or more embodiments shown and described herein;

[0043] FIG. 8C schematically depicts a side view of the alignment fixture of FIG. 8A, according to one or more embodiments shown and described herein;

[0044] FIG. 9 schematically depicts a top view of the alignment fixture of FIG. 8A positioned on a carrier plate, according to one or more embodiments shown and described herein;

[0045] FIG. 10A schematically depicts a perspective view of another alignment fixture, according to one or more embodiments shown and described herein;

[0046] FIG. 10B schematically depicts a top view of the alignment fixture of FIG. 10 A, according to one or more embodiments shown and described herein;

[0047] FIG. 10C schematically depicts a longitudinal side view of the alignment fixture of FIG. 10 A, according to one or more embodiments shown and described herein;

[0048] FIG. 10D schematically depicts a lateral side view of the alignment fixture of FIG. 10 A, according to one or more embodiments shown and described herein; and [0049] FIG. 11 schematically depicts the alignment fixture of FIG. 10A positioned over the carrier plate of FIG. 2, according to one or more embodiments shown and described herein.

DETAILED DESCRIPTION

[0050] Reference will now be made in detail to various embodiments of methods and apparatus for forming glass ceramic articles having improved optical quality, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0051] In general, described herein are alignment fixtures for use with glass stack configurations including a carrier plate, setter plates, and glass sheets. The glass sheets may undergo thermal treatment to form glass ceramic articles. The alignment fixtures described herein assist in aligning glass sheets within the glass stack and in aligning the glass stack with a setter plate and a carrier plate to improve thermal uniformity during the ceramming process and to reduce defects within the glass stack. Accordingly, the glass ceramic articles formed using the alignment fixtures described herein may exhibit improved optical qualities and less warp and fewer defects than glass ceramic articles made according to conventional processes. Various embodiments alignment fixtures will be described herein with specific reference to the appended drawings.

[0052] As used herein, the term“longitudinal direction” refers to the forward-rearward direction of the components of the glass stack and the alignment fixture {i.e., in the +/- X- direction as depicted). The term“lateral direction” refers to the cross-wise direction of the glass stack and the alignment fixture {i.e., in the +/- Y-direction as depicted), and is transverse to the longitudinal direction. The term“vertical direction” refers to the upward- downward direction of the glass stack and the alignment fixture {i.e., in the +/- Z-direction as depicted).

[0053] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom, vertical, horizontal - are made only with reference to the figures as drawn and are not intended to imply absolute orientation unless otherwise expressly stated.

[0054] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0055] As used herein, the singular forms“a,”“an” and“the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to“a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0056] In general, a process for forming a glass ceramic includes forming a glass article and ceramming the glass article to transform the glass article into a glass ceramic form. Referring to FIG. 1A, a side view of an example stack configuration 100 for ceramming is illustrated. The stack configuration 100 includes a carrier plate 120 supporting two setter plates 140, and a glass stack 160 positioned between the setter plates 140.

[0057] In some embodiments, insulation layers (not shown) may be located on the top surface of the upper setter plate 140 and one the bottom surface of the lower setter plate 140. The insulation layers may be formed from any material having a low thermal conductivity, and can reduce or even eliminate axial temperature gradients of the glass sheets 162 on the top and bottom of the glass stack 160.

[0058] As shown in FIG. 1A, the glass stack 160 includes individual glass sheets 162 that are stacked on top of one another in the vertical direction. In some embodiments, each glass sheet 162 may be separated from an adjacent glass sheet 162 and/or an adjacent setter plate 140 by a parting agent layer (not depicted). In these embodiments, the parting agent layer may reduce or even eliminates the sticking of the glass sheets 162 to one another during the ceramming process. In other embodiments, each glass sheet 162 may be positioned on or under an adjacent glass sheet 162 and/or an adjacent setter plate 140 without any intervening layers.

[0059] To form the glass ceramic, the glass stack 160 is heated at a temperature above its annealing point for a time sufficient to develop crystal nuclei. The heat treatment can be performed, for example, in a lehr or furnace. After being heated above its annealing point, the glass stack 160 is then further heated, usually at a higher temperature between the glass annealing point and the glass softening point, to develop the crystal phase. In various embodiments, the heat treatment, or ceramming process, includes heating the glass stack 160 to a nucleation temperature, maintaining the nucleation temperature for a predetermined period of time, heating the glass stack 160 to a crystallization temperature, and maintaining the crystallization temperature for a predetermined period of time. In some embodiments, the step of heating the glass stack 160 to a nucleation temperature can include heating the glass stack 160 to a nucleation temperature of about 700 degrees Celsius (°C) at a rate of 1-10 °C/minute (min). The glass stack 160 may be maintained at the nucleation temperature for a time of from about ¼ hour to about 4 hours, inclusive of the endpoints. The step of heating the glass stack 160 to the crystallization temperature can include heating the glass stack 160 to a crystallization temperature of about 800 °C at a rate of 1-10 °C/min. The glass stack 160 may be maintained at the nucleation temperature for a time of from about ¼ hour to about 4 hours.

[0060] However, it is contemplated that other heat treatment schedules (including varying times and/or temperatures) can be used, depending on the particular embodiment. In particular, the temperature-temporal profile of heat treatment steps are selected to produce one or more of the following attributes: crystalline phase(s) of the glass ceramic, proportions of one or more major crystalline phases and/or one or more minor crystalline phases and residual glass, crystal phase assemblages of one or more predominate crystalline phase and/or one or more minor crystalline phases and residual glass, and grain sizes or grain size distributions among one or more major crystalline phases and/or one or more minor crystalline phases, which in turn may influence the final integrity, quality, color and/or opacity of the resultant glass ceramic article.

[0061] Following heating to the nucleation temperature and maintaining that temperature for the predetermined time, the glass stack 160 is cooled back to room temperature. In various embodiments, the cooling rate is controlled down to a temperature of about 450 °C, after which the glass ceramic article formed by the glass stack 160 may be quenched without impacting the stress. Accordingly, in various embodiments, the ceramming process includes a controlled cooling at a rate of about 4 °C/min from the maximum temperature to a temperature of about 450 °C, followed by a quenching step to bring the temperature to approximately room temperature.

[0062] Referring to FIG. 1B, in some embodiments, the stack configuration 100 may include interlayer setter plates 112 positioned between adjacent glass stacks 160. Without being bound by theory, the inclusion of the interlayer setter plates 112 can increase heat transfer and decrease the temperature lag from the top of the stack configuration 100 to the bottom of the stack configuration 100. Additionally, the inclusion of interlayer setter plates 112 reduces the warp and does not significantly impact the stress in the glass ceramic article.

[0063] Referring to FIG. 2, a perspective view of the carrier plate 120 is schematically depicted. In the embodiment depicted in FIG. 2, the carrier plate 120 is an“open” carrier plate 120, and defines a plurality of apertures 124 extending through the carrier plate 120 in the vertical direction, and the carrier plate 120 is generally bounded by carrier plate edges 122. The apertures 124 may assist in achieving thermal uniformity in the glass stack 160 (FIG. 1 A) as the glass stack 160 is heated during the ceramming process.

[0064] Referring to FIG. 3, a perspective view of another example carrier plate 120 is schematically depicted. In the embodiment depicted in FIG. 3, the carrier plate 120 is generally“hollow” and includes a plurality of passages 126 extending through the carrier plate 120 in the longitudinal direction. In these embodiments, the carrier plate 120 may generally define a solid upper surface 128.

[0065] Referring to FIG. 4, a top view of multiple glass stacks 160 is depicted on a carrier plate 120. Each glass stack 160 is positioned on a setter plate 140 that is positioned on the carrier plate 120. While in the embodiment depicted in FIG. 4, the stack configuration 100 includes three glass stacks 160, it should be understood that the stack configuration 100 may include any suitable number of glass stacks 160.

[0066] In embodiments, each of the setter plates 140 are positioned on the carrier plate 120 such that setter plate edges 142 of the setter plates 140 are spaced apart from the carrier plate edges 122 of the carrier plate 120. In particular, in the embodiment depicted in FIG. 4, each of the setter plate edges 142 are positioned inward of the carrier plate edges 122 by a distance “d3.” The distance d3, in some embodiments, is between 20 millimeters (mm) and 30 mm, inclusive of the endpoints. In some embodiments, the distance d3 is about 25 mm.

[0067] Furthermore, each of the setter plates 140 are spaced apart from one another such that the setter plate edges 142 of adjacent setter plates 140 are spaced apart from one another by a distance“dl” In embodiments, the distance dl is between 10 mm and 20 mm, inclusive of the endpoints. In some embodiments, the distance dl is about 15 mm.

[0068] As depicted in FIG. 4, the glass stacks 160 are centered on the setter plates 140. In particular, the glass edges 164 of the each of the glass stacks 160 are positioned inward of the setter plate edges 142 of each of the corresponding setter plates 140 by a distance“d2.” In embodiments the distance d2 is between 10 mm and 20 mm, inclusive of the endpoints. In some embodiments, the distance d2 is about 15 mm.

[0069] Without being bound by theory, the positioning of the setter plates 140 on the carrier plate 120, and the positioning of the glass stacks 160 on the setter plates 140 impacts the thermal uniformity within the setter plates 140 and within the glass stacks 160 when heat is applied, for example as part of a ceramming process. Accordingly, by spacing each of the setter plates 140 apart from the carrier plate edges 122 by the same distance d3, and by spacing each of the setter plates 140 apart from each other by the same distance dl, thermal uniformity within the setter plates 140 may be improved as compared to configurations in which the setter plates 140 are not spaced equidistant from one another and spaced equidistant from the carrier plate edges 122. Additionally, by positioning the glass stacks 160 on the setter plates 140 such that the glass edges 164 are equally spaced from the setter plate edges 142 by the distance d2, thermal uniformity within the glass stacks 160 may be improved as compared to configurations in which the glass stacks 160 are not centered on the setter plates 140.

[0070] In embodiments, the specific distances dl, d2, and d3 may be selected to optimize throughput of a ceramming process ( e.g ., by increasing the number/quantity of glass stacks 160 positioned on a carrier plate 120), while maintaining a desired thermal performance throughout the ceramming process. [0071] In addition to aligning the glass stacks 160 to the setter plates 140 and aligning the setter plates 140 on the carrier plate 120, it is desirable to align individual glass sheets 162 (FIG. 1 A) to one another within the glass stack 160.

[0072] For example and referring to FIG. 5, an enlarged side view of a pair of adjacent glass sheets 162 is schematically depicted. As depicted, the upper glass sheet 162 is offset from the lower glass sheet 162, such that at least a portion of the upper glass sheet 162 overhangs the lower glass sheet 162 in the lateral direction. In particular, a glass edge 164 of the upper glass sheet 162 extends outward from a glass edge 164 of the lower glass sheet 162 by an overhang distance“OH” evaluated between the glass edges 164 in the lateral direction. When the upper and lower glass sheets 162 are heated, for example as part of the ceramming process, the upper and lower glass sheets 162 may, at points, be heated to a viscous state. In a viscous state, the portion of the upper glass sheet 162 that overhangs and is unsupported by the lower glass sheet 162 may yield under its own weight and may plastically deform in the vertical direction. This deformation may lead to manufacturing defects in the upper glass sheet 162, contributing to increased manufacturing losses and increased costs. The alignment fixtures disclosed herein can be used to minimize and/or eliminate the existence of overhang.

[0073] Referring to FIG. 6A, a top view of one embodiment of an alignment fixture 200 for aligning a glass stack 160 (FIG. 1A) to a setter plate 140 (FIG. 1A) is schematically depicted. The alignment fixture 200 generally includes a lateral portion 210 extending in the lateral direction and a longitudinal portion 220 oriented transverse to the lateral portion 210 and extending in the longitudinal direction.

[0074] Referring to FIG. 6B, a section view of the alignment fixture 200 along section 6B- 6B of FIG. 6 A is schematically depicted. The lateral portion 210 of the alignment fixture 200 generally defines a lateral glass engagement face 212 that is oriented to face in the longitudinal direction and a lateral setter engagement face 214 oriented to face in the longitudinal direction. The lateral glass engagement face 212 engages a lateral glass edge 164 (FIG. 4) of a glass sheet 162 (FIG. 4) and the lateral setter engagement face 214 engages a lateral setter plate edge 142 (FIG. 4) of a setter plate 140 (FIG. 4) to align the glass sheet 162 to the setter plate 140, as described in greater detail herein. [0075] In embodiments, the lateral setter engagement face 214 is spaced apart from the lateral glass engagement face 212 in the longitudinal direction. In particular, the lateral setter engagement face 214 is positioned outward (i.e., in the -X-direction as depicted) of the lateral glass engagement face 212 by the distance d2. As noted above, the distance d2 corresponds to a desired spacing between the glass edges 164 (FIG. 4) and the setter plate edges 142 (FIG. 4).

[0076] The lateral portion 210 further defines a lateral outer face 216 positioned opposite the lateral glass engagement face 212 and the lateral setter engagement face 214 and oriented to face in the longitudinal direction. In particular, the lateral outer face 216 is oriented to face outward in the longitudinal direction (i.e., in the -X-direction as depicted), while the lateral glass engagement face 212 and the lateral setter engagement face 214 are oriented to face inward in the longitudinal direction (i.e., in the +X-direction as depicted).

[0077] In some embodiments, the lateral outer face 216 is spaced apart from the lateral setter engagement face 214 by the distance d3. As noted above, the distance d3 corresponds to a desired spacing between the setter plate edges 142 (FIG. 4) and the carrier plate edges 122 (FIG. 4).

[0078] Referring to FIG. 6C, a section view of the alignment fixture 200 along section 6C- 6C of FIG. 6A is schematically depicted. The longitudinal portion 220 of the alignment fixture 200 generally defines a longitudinal glass engagement face 222 that is oriented to face in the lateral direction and a longitudinal setter engagement face 224 oriented to face in the lateral direction. The longitudinal glass engagement face 222 engages a longitudinal glass edge 164 (FIG. 4) of a glass sheet 162 (FIG. 4) and the longitudinal setter engagement face 224 engages a longitudinal setter plate edge 142 (FIG. 4) of a setter plate 140 (FIG. 4) to align the glass sheet 162 to the setter plate 140, as described in greater detail herein. In some embodiments, a height“GH” of the lateral glass engagement face 212 (FIG. 6B) and/or the longitudinal glass engagement face 222 evaluated in the vertical direction may correspond to a desired height of a glass stack 160 (FIG. 1A). In other embodiments, the lateral glass engagement face 212 (FIG. 6B) and/or the longitudinal glass engagement face 222 may include a visual marking corresponding to a desired height of a glass stack 160 to provide visual feedback to an operator when a desired amount of glass sheets 162 (FIG. 1A) have been included in the glass stack 160. [0079] In embodiments, the longitudinal setter engagement face 224 is spaced apart from the longitudinal glass engagement face 222 in the lateral direction. In particular, the longitudinal setter engagement face 224 is positioned outward (i.e., in the -Y-direction as depicted) of the longitudinal glass engagement face 222 by the distance d2. As noted above, the distance d2 corresponds to a desired spacing between the glass edges 164 (FIG. 4) and the setter plate edges 142 (FIG. 4).

[0080] The longitudinal portion 220 further defines a longitudinal outer face 226 positioned opposite the longitudinal glass engagement face 222 and the longitudinal setter engagement face 224 and oriented to face in the lateral direction. In particular, the longitudinal outer face 226 is oriented to face in outward in the lateral direction (i.e., in the - Y-direction as depicted), while the longitudinal glass engagement face 222 and the longitudinal setter engagement face 224 are oriented to face inward in the lateral direction (i.e., in the +Y-direction as depicted).

[0081] In some embodiments, the longitudinal outer face 226 is spaced apart from the longitudinal setter engagement face 224 by the distance dl. As noted above, the distance dl corresponds to a desired spacing between the setter plate edges 142 (FIG. 4) of adjacent setter plates 140 (FIG. 4).

[0082] Referring again to FIG. 6A, in embodiments, the alignment fixture 200 defines a corner aperture 240 positioned between the longitudinal portion 220 and the lateral portion 210. The corner aperture 240 extends through the alignment fixture 200 in the vertical direction and is defined by an aperture face 242. While the embodiment depicted in FIG. 6A includes a comer aperture 240 with a generally circular shape, it should be understood that the corner aperture 240 may include any suitable shape, for example and without limitation, a rectangular shape, a polygonal shape, or the like.

[0083] In embodiments, the aperture face 242 is extends outward (i.e., in the -X-direction and the -Y-direction) from the longitudinal glass engagement face 222 and the lateral glass engagement face 212. For example, the longitudinal glass engagement face 222 and the lateral glass engagement face 212 define a glass sheet envelope 246, and the aperture face 242 is spaced apart from the glass sheet envelope 246. When glass sheets 162 (FIG. 1A) are engaged with the alignment fixture 200, the glass sheets 162 are generally positioned within the glass sheet envelope 246 and engage the longitudinal glass engagement face 222 and the lateral glass engagement face 212. Comers of the glass sheets 162 (FIG. 1A) positioned between adjacent glass edges 164 (FIG. 4) are generally positioned within the corner aperture 240 and within the glass sheet envelope 246. Because the aperture face 242 of the corner aperture 240 is spaced apart from the glass sheet envelope 246, the comers of the glass sheets 162 (FIG. 1A) are spaced apart from and generally do not contact the aperture face 242 when the glass sheets 162 are engaged with the alignment fixture 200.

[0084] In embodiments in which the glass sheets 162 (FIG. 1A) include a rectangular shape, the corners of the glass sheets 162 may include a sharp edge, such that adjacent glass edges 164 (FIG. 4) are at or near a perpendicular orientation with respect to one another. Without being bound by theory, these sharp edges may contribute to a stress concentration at the corners of the glass sheets 162 (FIG. 1 A) resulting from the sharp geometric discontinuity at the corners of the glass sheets 162. Accordingly, the comers of the glass sheets 162 (FIG. 1A) may be particularly susceptible to breakage as compared to other portions of the glass sheets 162. Because the alignment fixture 200 includes the corner aperture 240 with the aperture face 242 spaced apart from the glass sheet envelope 246, the corners of the glass sheets 162 (FIG. 1A) may avoid contact with the alignment fixture 200, thereby reducing stress on the glass sheets 162 and reducing breakage of the glass sheets 162 as they engage the alignment fixture 200.

[0085] Still referring to FIG. 6 A, in embodiments, the lateral setter engagement face 214 and the longitudinal setter engagement face 224 define a setter plate envelope 244. In some embodiments, the aperture face 242 of the corner aperture 240 is also spaced apart from the setter plate envelope 244.

[0086] In embodiments in which the setter plates 140 (FIG. 4) include a rectangular shape, the corners of the setter plates 140 may include a sharp edge, such that adjacent setter edges 142 (FIG. 4) are at or near a perpendicular orientation with respect to one another. Similar to the corners of the glass sheets 162 (FIG. 1A) as described above, the corners of the setter plates 140 (FIG. 4) may be susceptible to stress concentration and breakage. Because the alignment fixture 200 includes the comer aperture 240 with the aperture face 242 spaced apart from the setter plate envelope 244, the comers of the setter plates 140 (FIG. 4) may avoid contact with the alignment fixture 200, thereby reducing stress on the setter plates 140 and reducing breakage of the setter plates 140 as they engage the alignment fixture 200.

[0087] Referring collectively to FIGS. 6 A and 7, a pair of alignment fixtures 200 is depicted on a carrier plate 120 to align a glass stack 160 (FIG. 1A) to a setter plate 140. To align glass sheets 162 on the setter plate 140, one alignment fixture 200 is positioned along adjacent setter plate edges 142 of the setter plate 140, and the other alignment fixture 200 is positioned along the opposing adjacent setter plate edges 142. More particularly, the longitudinal setter engagement face 224 of the longitudinal portion 220 of each of the alignment fixtures 200 engages the longitudinal setter plate edges 142 of the setter plate 140, and the lateral setter engagement face 214 of the lateral portion 210 of each of the alignment fixtures 200 engages the lateral setter plate edges 142 of the setter plate 140.

[0088] Glass sheets 162 may be positioned on the setter plate 140 between the alignment fixtures 200. More particularly, longitudinal glass edges 164 of the glass sheets 162 engage the longitudinal glass engagement face 222 of the longitudinal portion 220 of each of the alignment fixtures 200, and lateral glass edges 164 of the glass sheets 162 engage the lateral glass engagement face 212 of the lateral portion 210 of each of the alignment fixtures 200. With the glass edges 164 of the glass sheets 162 engaged with the lateral glass engagement faces 212 and the longitudinal glass engagement faces 222 of the alignment fixtures 200, a glass sheet 162 may be constrained within the alignment fixtures 200 in the lateral and the longitudinal directions by the alignment fixtures 200. Furthermore, with the setter plate edges 142 of the setter plate 140 engaged with the lateral setter engagement faces 214 a and the longitudinal setter engagement faces 224 of the alignment fixtures 200, the setter plate 140 is constrained in the lateral and the longitudinal directions by the alignment fixtures 200.

[0089] As noted above, the lateral setter engagement faces 214 of the alignment fixtures 200 are spaced apart from the lateral glass engagement faces 212 by the distance d2. Furthermore, the longitudinal setter engagement faces 224 of the alignment fixtures 200 are spaced apart from the longitudinal glass engagement faces 222 by the distance d2. Accordingly, the glass edges 164 of a glass sheet 162 engaged with the lateral glass engagement faces 212 and the longitudinal glass engagement faces 222 are spaced apart from setter plate edges 142 of the setter plate 140 by the distance d2. In other words, by engaging the glass sheet 162 and the setter plate 140 with the alignment fixtures 200, the glass sheet 162 may be centered on the setter plate 140, with each of the glass edges 164 of the glass sheet 162 spaced apart from the setter plate edges 142 of the setter plate 140 by the same distance d2. As described above, the positioning of the glass sheets 162 on the setter plate 140 affects thermal uniformity of the glass sheets 162 on the setter plate 140 when exposed to a heat source, such as during a ceramming process. By centrally positioning the glass sheet 162 on the setter plate 140, the thermal uniformity within the glass sheet 162 may be improved when exposed to a heat source, as compared to configurations in which the glass sheets 162 are not centrally positioned on the setter plate 140.

[0090] In some embodiments, a single glass sheet 162 is positioned on the setter plate 140, and after the glass sheet 162 and the setter plate 140 are engaged with the alignment fixtures 200, subsequent glass sheets 162 may be positioned on top of one another to form the glass stack 160 (FIG. 1A) within the glass sheet envelope 246 defined by the alignment fixtures 200. In other embodiments, multiple glass sheets 162 may be stacked on the setter plate 140, and a user may engage the multiple glass sheets 162 with the alignment fixtures 200 to align the glass stack 160 (FIG. 1A) with the setter plate 140.

[0091] In embodiments, each of the glass sheets 162 engage the same longitudinal glass engagement faces 222 and the same lateral glass engagement faces 212, such that the glass sheets 162 are stacked directly on top of one another. In other words, the overhang distance OH (FIG. 5) evaluated between glass edges 164 of adjacent glass sheets 162 may be substantially zero millimeters after the glass sheets 162 are engaged with and aligned with the alignment fixtures 200. In some embodiments, the overhang distance OH (FIG. 5) evaluated between glass edges 164 of adjacent glass sheets 162 is less than 2 millimeters. As described above, by reducing the overhang distance OH between adjacent glass sheets 162, defects in the glass sheets 162 resulting from the glass sheets 162 deforming under their own weight during the cerraming process may be reduced and/or eliminated.

[0092] As described above, in some embodiments, the distance between the lateral outer face 216 and the lateral setter engagement face 214 of the alignment fixtures 200 corresponds to the distance d3 between the carrier plate edges 122 of the carrier plate 120 and the setter plate edge 142 of the setter plate 140. Accordingly, by aligning the lateral outer faces 216 of the alignment fixtures 200 and engaging the setter plate edge 142 of the setter plates 140 with the lateral setter engagement faces 214 of the alignment fixtures 200, the setter plate 140 may be positioned on the carrier plate 120 with the setter plate edge 142 spaced apart from the carrier plate edges 122 at the desired distance d3. Accordingly, the alignment fixtures 200 may assist in aligning the setter plates 140 with respect to the carrier plate 120, the glass stack 160 (FIG. 1A) with respect to the carrier plate 120, and the glass sheets 162 within the glass stack 160. With the glass stack 160 (FIG. 1A) formed on the setter plate 140, another setter plate 140 may be positioned on the carrier plate 120, such that another glass stack 160 may be positioned on that setter plate 140.

[0093] For example, in the embodiment depicted in FIG. 7, another setter plate 140 is positioned adjacent to the setter plate 140 engaged with the alignment fixtures 200. As depicted, the setter plate 140 may be engaged with longitudinal outer face 226 of one of the alignment fixtures 200. As noted above, the longitudinal outer face 226 of the alignment fixture 200 is spaced apart from the longitudinal setter engagement face 224 (FIG. 6C) by the distance dl. Accordingly, by engaging the setter plate 140 against the longitudinal outer face 226, the setter plate 140 may be spaced apart from the adjacent setter plate 140 engaged with the pair of alignment fixtures 200 in the lateral direction by the desired distance dl. In this way, the alignment fixtures 200 may further assist in ensuring adjacent setter plates 140 positioned on the carrier plate 120 are spaced apart as desired.

[0094] In some embodiments, the alignment fixtures 200 are formed of a material substantially softer than the glass sheets 162, such that the alignment fixtures 200 do not scratch or deform glass sheets 162 engaged with the alignment fixtures 200. The alignment fixtures 200 may be formed of a material that is also substantially softer than the carrier plate 120 and/or the setter plates 140. In embodiments, the alignment fixtures 200 may be formed of any suitable material, for example and without limitation, a thermoplastic, polyoxymethylene, Ultra-high-molecular-weight polyethylene (UHMW), or the like. In one embodiment, the alignment fixture 200 is formed from Delrin available from E. I. du Pont de Nemours and Company.

[0095] Referring to FIGS. 8A-8C, a perspective view, a top view, and a side view of another alignment fixture 200 are schematically depicted, respectively. Like the embodiment described above and depicted in FIGS. 6A-6C, the alignment fixture 200 includes the longitudinal portion 220 including the longitudinal glass engagement face 222 and the longitudinal setter engagement face 224. The alignment fixture 200 further includes the lateral portion 210 including the lateral glass engagement face 212 and the lateral setter engagement face 214, and the corner aperture 240 including the aperture face 242 spaced apart from the setter plate envelope 244 and the glass sheet envelope 246. In the embodiment depicted in FIGS. 8A-8C, the alignment fixture 200 further includes a swing arm 230 pivotally coupled to the longitudinal portion 220 opposite the lateral portion 210. In particular, in some embodiments, the swing arm 230 is pivotally coupled to the longitudinal portion 220 at a pivot member 232. In embodiments, the pivot member 232 may include a pin or the like that allows the swing arm 230 to rotate with respect to the longitudinal portion 220 about an axis extending through the pivot member 232 in a direction that is substantially parallel to the vertical direction.

[0096] The swing arm 230 generally defines a glass engagement face 234 that engages a glass edge 164 (FIG. 7) of a glass sheet 162 (FIG. 7), and a setter engagement face 236 that engages a setter plate edge 142 (FIG. 7) of a setter plate 140 (FIG. 7). In embodiments, the swing arm 230 is repositionable between an engaged position, in which the glass engagement face 234 is positioned within the glass sheet envelope 246 that corresponds to a glass sheet 162 (FIG. 7), and a disengaged position, in which the glass engagement face 234 is positioned outside the glass sheet envelope 246. The setter engagement face 236 may also be positioned in the setter plate envelope 244 that corresponds to a setter plate 140 (FIG. 7) when the swing arm 230 is in the engaged position, and may be spaced apart from the setter plate envelope 244 when the swing arm 230 is in the disengaged position. In this manner, the swing arm 230 may selectively engage a glass edge 164 (FIG. 7) of a glass sheet 162 (FIG. 7) and a setter plate edge 142 (FIG. 7) of a setter plate 140 (FIG. 7).

[0097] In some embodiments, the alignment fixture 200 further includes a handle 202 coupled to the swing arm 230. A user may grip the handle 202 to move the swing arm 230 between the engaged position and the disengaged position. In the embodiment depicted in FIGS. 8A-8C, the alignment fixture 200 further includes a handle 202 coupled to the lateral portion 210. A user may grip the handle 202 coupled to the lateral portion 210 and the handle 202 coupled to the swing arm 230 to move the swing arm 230 into the engaged position. While the embodiment depicted in FIGS. 8A-8C includes the handle 202 coupled to the lateral portion 210, it should be understood that the alignment fixture 200 may include any suitable number of handles 202 positioned on the lateral portion 210 and the longitudinal portion 220 of the alignment fixture 200 to assist a user in manipulating the alignment fixture 200.

[0098] Referring to FIG. 9, a top view of an alignment fixture 200 engaged with a glass sheet 162 and a setter plate 140 is schematically depicted. Similar to the embodiment described above and depicted in FIG. 7, adjacent glass edges 164 are engaged with the longitudinal portion 220 and the lateral portion 210 of the alignment fixture 200. In particular, adjacent glass edges 164 of the glass sheet 162 are engaged with the longitudinal glass engagement face 222 and the lateral glass engagement face 212 of the alignment fixture 200. When the swing arm 230 is in the engaged position, the glass engagement face 234 of the swing arm 230 engages a glass edge 164 positioned opposite the lateral portion 210, and the setter engagement face 236 of the swing arm 230 engages a setter plate edge 142 of the setter plate 140 positioned opposite the lateral portion 210. By engaging the glass edge 164 of the glass sheet 162 and the setter plate edge 142 of the setter plate 140, the swing arm 230 may move the glass sheet 162 and the setter plate 140 toward the lateral portion 210 in the longitudinal direction ( i.e ., in the -X-direction as depicted). By moving the glass sheet 162 and the setter plate 140 toward the lateral portion 210, the swing arm 230 may assist in ensuring that the glass sheet 162 and the setter plate 140 are engaged with the lateral glass engagement face 212 and the lateral setter engagement face 214, respectively. With the glass sheet 162 and the setter plate 140 engaged with the lateral glass engagement face 212 and the lateral setter engagement face 214, respectively, the glass sheet 162 may be positioned on the setter plate 140 with the glass edge 164 spaced apart from the setter plate edge 142 by the desired distance d2.

[0099] Because the swing arm 230 is pivotally coupled to the longitudinal portion 220 of the alignment fixture 200, the swing arm 230 may assist in reducing the ergonomic burden on a user to ensure engagement of the glass sheet 162 and the setter plate 140 with the lateral portion 210 of the alignment fixture 200. For example, the swing arm 230 may be easier for a user to manipulate reaching across the glass sheet 162 in the longitudinal direction ( i.e ., across the glass sheet 162 in the +X-direction as depicted), as compared to using a tool separate from the alignment fixture 200 or attempting to grip the glass sheet 162 and the setter plate 140 by hand. While one glass sheet 162 is depicted in FIG. 9, it should be understood that multiple glass sheets 162 may be engaged with the swing arm 230 and the lateral portion 210 of the alignment fixture 200, such that the glass sheets 162 may be aligned in a glass stack 160 (FIG. 1 A).

[00100] Referring collectively to FIGS. 10A-10D, a perspective view, a top view, a longitudinal side view, and a lateral side view of another embodiment of the alignment fixture 200 are schematically depicted, respectively. Like the embodiment described above and depicted in FIGS. 6A-6C, the alignment fixture 200 includes the longitudinal portion 220 including the longitudinal glass engagement face 222 and the longitudinal setter engagement face 224. The alignment fixture 200 further includes the lateral portion 210 including the lateral glass engagement face 212 and the lateral setter engagement face 214, and the corner aperture 240 including the aperture face 242 spaced apart from the setter plate envelope 244 and the glass sheet envelope 246. In the embodiment depicted in FIGS. 10A-10D, the alignment fixture 200 further includes at least one carrier pin assembly 250 coupled to the alignment fixture 200. In the embodiment depicted in FIGS. 10A-10D, the alignment fixture 200 includes two carrier pin assemblies 250 coupled to the longitudinal outer face 226, and two carrier pin assemblies 250 coupled to the lateral outer face 216. Each of the carrier pin assemblies 250 generally include a carrier pin 252 extending downward from the alignment fixture 200 in the vertical direction. In embodiments, the carrier pin assemblies 250 may further include a plate member 254. The plate members 254 of the carrier pin assemblies 250 coupled to the longitudinal portion 220 are engaged with and coupled to the longitudinal outer face 226, and the plate members 254 of the carrier pin assemblies 250 coupled to the lateral portion 210 are engaged with and coupled to the lateral outer face 216.

[00101] In some embodiments, the longitudinal portion 220 and/or the lateral portion 210 may define apertures 248 extending into the longitudinal outer face 226 and/or the lateral outer face 216. The apertures 248 on the longitudinal portion 220 are generally spaced apart from one another in the longitudinal direction and the apertures 248 on the lateral portion 210 are generally spaced apart from one another in the lateral direction. The plate members 254 of the carrier pin assemblies 250 may be selectively coupled to the alignment fixture 200 through ones of the apertures 248. By selectively coupling the carrier pin assemblies 250 to different ones of the apertures 248 of the longitudinal portion 220, the position of the carrier pin assemblies 250 on the longitudinal portion 220 may be adjustable in the longitudinal direction. Similarly, by selectively coupling the carrier pin assemblies 250 to different ones of the apertures 248 of the lateral portion 210, the position of the carrier pin assemblies 250 on the lateral portion 210 may be adjustable in the lateral direction.

[00102] In some embodiments, the carrier pin assemblies 250 are rotatable with respect to the alignment fixture 200. For example and referring to the carrier pin assemblies 250 coupled to the longitudinal portion 220, the carrier pin assemblies 250 are generally rotatable with respect to the alignment fixture 200 about the lateral direction. Similarly, the carrier pin assemblies 250 coupled to the lateral portion 210 are generally rotatable with respect to the alignment fixture 200 about the longitudinal direction. In some embodiments, the carrier pin assemblies 250 may further include a biasing member 247 coupled to each of the carrier pin assemblies 250. The biasing members 247 may bias the carrier pin assemblies 250 to rotate with respect to the alignment fixture 200. The biasing members 247 may include any suitable construction and may include, for example and without limitation, a torsion spring, a tension spring, a compression spring, or the like.

[00103] Referring to FIG. 11, a perspective view of the alignment fixture 200 of FIGS. 10A- 10D positioned over the carrier plate 120 of FIG. 4 is schematically depicted. The carrier pins 252 are insertable within the apertures 124 of the carrier plate 120 to retain the position of the alignment fixture 200 on the carrier plate 120. In particular, the carrier pins 252 of the alignment fixture 200 may be inserted within the apertures 124 of the carrier plate 120 as the alignment fixture 200 is lowered onto the carrier plate 120 in the vertical direction. Once glass sheets 162 (FIG. 1A) are positioned on the carrier plate 120 ( e.g ., the glass sheets 162 being positioned on top of a setter plate 140 on the carrier plate 120) to form a glass stack 160 (FIG. 1A), the carrier pins 252 may be rotated with respect to the alignment fixture 200 to remove the carrier pins 252 from the apertures 124. For example, the carrier pins 252 positioned on the longitudinal portion 220 may rotate about the lateral direction, while the carrier pins 252 on the lateral portion 210 may rotate about the longitudinal direction to remove the carrier pins 252 from the apertures 124 of the carrier plate 120.

[00104] With the carrier pins 252 of the alignment fixture 200 removed from the apertures 124 of the carrier plate 120, the alignment fixture 200 may be removed from the carrier sheet without lifting the alignment fixture 200 from the carrier plate 120 in the vertical direction. In other words, the alignment fixture 200 may be removed from the carrier plate 120 by moving the alignment fixture 200 in the lateral and/or the longitudinal directions. Because the alignment fixture 200 may be removed from the carrier plate 120 in the lateral and/or the longitudinal directions, the alignment fixture 200 may be removed with minimal disturbance to the glass stack 160 (FIG. 1 A) formed on the carrier plate 120. As described above, in some embodiments, the alignment fixture 200 includes biasing members 247 that bias the carrier pins 252 to rotate with respect to the alignment fixture 200. In these embodiments, the carrier pins 252 may be selectively rotated out of the apertures 124 of the carrier plate 120 by the biasing members 247.

[00105] Accordingly, it should now be understood that embodiments described herein include alignment fixtures for use with glass stack configurations including a carrier plate, setter plates, and glass sheets. The glass sheets may undergo thermal treatment to form glass ceramic articles. The alignment fixtures described herein assist in aligning glass sheets within the glass stack and in aligning the glass stack with a setter plate and a carrier plate to improve thermal uniformity during the ceramming process and to reduce defects within the glass stack. Accordingly, the glass ceramic articles formed using the alignment fixtures described herein may exhibit improved optical qualities and less warp and fewer defects than glass ceramic articles made according to conventional processes.

Claims

What is claimed is:

1. An alignment fixture for aligning glass sheets within a glass stack, the alignment fixture comprising:

a lateral glass engagement face oriented to face in the longitudinal direction; and

a lateral setter engagement face oriented to face in the longitudinal direction, wherein the lateral setter engagement face is spaced apart from the lateral glass engagement face; and

a corner aperture extending through the alignment fixture in a vertical direction that is transverse to the longitudinal direction and the lateral direction, wherein the corner aperture defines an aperture face that is spaced apart from a glass sheet envelope defined by the longitudinal glass engagement face and the lateral glass engagement face.

2. The alignment fixture of claim 1, wherein the aperture face is spaced apart from a setter plate envelope defined by the longitudinal setter engagement face and the lateral setter engagement face.

3. The alignment fixture of claim 1 or claim 2, wherein the longitudinal portion further comprises a longitudinal outer face, and a distance evaluated between the longitudinal outer face and the longitudinal setter engagement face is 15 millimeters.

4. The alignment fixture of any one of claims 1-3, wherein the lateral portion further comprises a lateral outer face, and a distance evaluated between the lateral outer face and the lateral setter engagement face is 25 millimeters.

5. The alignment fixture of any one of claims 1-4, further comprising a swing arm pivotally coupled to the longitudinal portion opposite the lateral portion.

6. The alignment fixture of claim 5, wherein the swing arm defines a glass engagement face, and wherein the swing arm is repositionable between a disengaged position, in which the glass engagement face is positioned outside of the glass sheet envelope, and an engaged position, in which the swing arm is positioned within the glass sheet envelope.

7. The alignment fixture of any one of claims 1-6, further comprising a carrier pin assembly coupled to one of the longitudinal portion and the lateral portion, the carrier pin assembly comprising a carrier pin extending outward from the longitudinal portion or the lateral portion in the vertical direction.

8. The alignment fixture of claim 7, further comprising a biasing member coupled to the carrier pin assembly.

9. A method for ceramming a glass stack, the method comprising:

positioning a setter plate on a carrier plate;

positioning the glass sheet on the setter plate; and

10. The method of claim 9, wherein the glass sheet is a first glass sheet, and wherein the method further comprises:

engaging adjacent glass edges of a second glass sheet with the lateral portion and the longitudinal portion of the alignment fixture; and

positioning the second glass sheet on the first glass sheet.

11. The method of claim 10, wherein:

12. The method of any one of claims 9-11, further comprising:

rotating a swing arm pivotally coupled to the longitudinal portion;

engaging the swing arm with a glass edge of the glass sheet; and

13. The method of any one of claims 9-12, further comprising:

rotating a swing arm pivotally coupled to the longitudinal portion;

engaging the swing arm with a setter plate edge of the setter plate; and

14. The method of any one of claims 9-13, further comprising inserting a carrier pin coupled to the alignment fixture into an aperture of the carrier plate.

15. The method of claim 14, further comprising, prior to heating the carrier plate, rotating the carrier pin with respect to the carrier plate, moving the carrier pin outside of the aperture of the carrier plate.

16. The method of any one of claims 9-15, wherein the alignment fixture is a first alignment fixture, and the method further comprises engaging adjacent glass edges of the glass sheet with a lateral portion and a longitudinal portion of a second alignment fixture positioned opposite the first alignment fixture.

17. The method of any one of claims 9-16, wherein the setter plate is a first setter plate, and wherein the method further comprises:

positioning a second setter plate on the carrier plate, spaced apart from the first setter plate; and

18. A method for ceramming a glass stack, the method comprising:

positioning a setter plate on a carrier plate;

engaging adjacent setter plate edges of the setter plate with a lateral setter engagement face and a longitudinal setter engagement face of an alignment fixture, wherein the lateral setter engagement face is oriented transverse to the longitudinal setter engagement face; engaging adjacent glass edges of a glass sheet with a lateral glass engagement face and a longitudinal glass engagement face of the alignment fixture, wherein the lateral glass engagement face is aligned with and spaced apart from the lateral setter engagement face in a longitudinal direction and wherein the longitudinal glass engagement face is aligned with and spaced apart from the longitudinal setter engagement face in a lateral direction;

positioning a corner of the glass sheet within a corner aperture extending through the alignment fixture in a vertical direction that is transverse to the longitudinal direction and the lateral direction, wherein the comer aperture defines an aperture face that is spaced apart the corner of the glass sheet;

positioning the glass sheet on the setter plate; and

19. The method of claim 18, wherein the glass sheet is a first glass sheet, and wherein the method further comprises:

20. The method of claim 18 or claim 19, wherein the setter plate is a first setter plate, and wherein the method further comprises:

engaging adjacent setter plate edges of the first setter plate with the lateral setter engagement face and the longitudinal setter engagement face of the alignment fixture while engaging an outer face of the alignment fixture with a setter plate edge of the second setter plate.