阅读说明：本技术 多晶材料的固态转化 (Solid state conversion of polycrystalline materials ) 是由 T·D·凯查姆 李兴华 王岩 于 2021-04-08 设计创作，主要内容包括：本发明描述了通过多晶材料的固态转化制造结晶材料(例如大晶体材料)的系统、装置和技术。装置可被配置为使用多个热源同时加热一定体积的带材,例如氧化铝带材。例如,第一热源可以加热带材的第一体积,第二热源可以同时加热第二体积(例如在第一体积内),其中所述带材可以包含多晶材料。所述同时加热可以至少在第二体积中驱动多晶材料中的晶粒生长,这可以将多晶材料转化为结晶材料,该结晶材料包含比所述多晶材料的一个或多个晶粒更大的一个或多个晶粒。经处理的带材可包含大晶体材料或单晶材料。(Systems, devices, and techniques for producing crystalline materials (e.g., large crystal materials) by solid state conversion of polycrystalline materials are described. The apparatus may be configured to simultaneously heat a volume of strip, such as alumina strip, using a plurality of heat sources. For example, a first heat source may heat a first volume of the ribbon, and a second heat source may simultaneously heat a second volume (e.g., within the first volume), wherein the ribbon may comprise polycrystalline material. The simultaneous heating may drive grain growth in the polycrystalline material at least in the second volume, which may convert the polycrystalline material into a crystalline material comprising one or more grains larger than the one or more grains of the polycrystalline material. The treated strip may comprise a large crystal material or a single crystal material.)

1. A method of manufacturing, comprising:

heating a first volume of a ribbon using a first heat source, the ribbon comprising a polycrystalline material; and

simultaneously heating a second volume of the ribbon while the ribbon is moving relative to at least a second heat source, the second volume being within the first volume, using the second heat source and using the first heat source, wherein the heating using the first heat source and the second heat source converts at least a portion of the polycrystalline material of the ribbon within the second volume to crystalline material comprising one or more grains that are larger than the plurality of grains of the polycrystalline material.

2. The method of claim 1, wherein simultaneously heating the second volume using the second heat source comprises:

heating at least a first surface of the strip using a first heat source, wherein heating at least the first surface of the strip heats a first volume of the strip; and

simultaneously heating a second surface of the strip, the second surface being different from the first surface, wherein the polycrystalline material is converted from the first surface of the strip to crystalline material and extends from the first surface to a first depth of the strip.

3. The method of claim 1 or 2, wherein simultaneously heating the second volume using the second heat source comprises:

scanning a second volume of the ribbon with the second heat source while heating the first and second volumes by the first heat source.

4. The method of claim 1, further comprising:

depositing one or more seed crystals on the polycrystalline material of the ribbon prior to simultaneously heating using the first and second heat sources, wherein an orientation of the crystalline material is based at least in part on a shape of the one or more seed crystals or an orientation of the one or more seed crystals, or both.

5. The method of claim 1, further comprising:

moving the ribbon relative to the second heat source at a speed of at least 0.2 inches per minute.

6. The method of claim 1, wherein the first heat source comprises a convective heat source or a first radiant heat source, or a combination thereof, for heating at least the first volume, and wherein the second heat source comprises a second radiant heat source for irradiating the second volume with photons, wherein the first volume is larger than the second volume.

7. The method of claim 1, wherein the first heat source comprises at least one of a flame, an oven, a furnace, or a microwave, and wherein the second heat source comprises at least one of a laser or a focused infrared source.

8. The method of claim 1, further comprising:

heating a first volume of the ribbon using a third heat source, wherein the first volume comprises a first subset of polycrystalline material and a second subset of crystalline material; and

simultaneously heating a second volume of the ribbon while the ribbon is moving relative to at least a fourth heat source, the second volume being within the first volume, using the fourth heat source and using the third heat source, wherein heating using the third heat source and the fourth heat source converts polycrystalline material of at least a portion of the first subset of the ribbon within the second volume to crystalline material comprising one or more grains larger than the plurality of grains of the polycrystalline material, and wherein a depth of the crystalline material of the ribbon increases based at least in part on the simultaneous heating using the third heat source and the fourth heat source.

9. The method of claim 1, wherein heating using the first and second heat sources converts at least a portion of the polycrystalline material of the ribbon within the second volume to the crystalline material when the ribbon is in the solid state.

10. The method of claim 1, wherein the polycrystalline material of the ribbon is at least partially sintered.

11. A manufacturing apparatus, comprising:

a support member for supporting a ribbon comprising a polycrystalline material;

a moving means for moving the strip;

a first heat source for heating a first volume of the ribbon; and

a second heat source for simultaneously heating a second volume of the ribbon within the first volume simultaneously heated by the first heat source, the moving component configured to move the ribbon relative to at least the second heat source, wherein the first heat source and the second heat source are configured to convert at least a portion of the polycrystalline material of the ribbon into a crystalline material comprising one or more grains larger than the plurality of grains of the polycrystalline material based at least in part on heating the first volume and the second volume.

12. The apparatus of claim 11, wherein the first heat source is positioned to apply heat to at least a first surface of the ribbon and the second heat source is positioned to apply heat to a second surface of the ribbon different from the first surface, wherein the polycrystalline material is converted from the first surface of the ribbon to a crystalline material and extends from the first surface to a first depth of the ribbon.

13. The apparatus of claim 11, wherein the first heat source is positioned to apply heat to at least a first surface of the ribbon, and the second heat source is positioned to apply heat to the first surface of the ribbon, wherein the polycrystalline material is converted from the first surface of the ribbon to a crystalline material and extends from the first surface to a first depth of the ribbon.

14. The apparatus of claim 11, wherein the second heat source comprises an radiant heat source configured to scan a second volume of the ribbon using a raster pattern or a scanning pattern, or both.

15. The device of claim 11, further comprising:

a tension member for applying tension to the ribbon to alter the shape of the ribbon when the first volume and the second volume are heated simultaneously.

16. A tape, comprising:

a first volume comprising polycrystalline material, the first volume extending from a first side of the ribbon to a first depth of the ribbon; and

a second volume comprising crystalline material extending from a second side of the ribbon opposite the first side of the ribbon to a second depth of the ribbon, the crystalline material having a grain size of at least 100 microns and comprising one or more grains larger than the plurality of grains of polycrystalline material, wherein the second depth is at least 1 micron.

17. The ribbon of claim 16, wherein the polycrystalline material comprises a polycrystalline ceramic material, a polycrystalline metallic material, or a semiconductor material, and wherein the crystalline material comprises a sapphire material or a single crystal material.

18. A strip material according to claim 16, wherein the crystalline material has a grain size with a transverse dimension of at least 1 mm and a longitudinal dimension of at least 1 mm.

19. The tape of claim 16, wherein the second depth of the second volume extends to about a thickness of the tape, the thickness of the tape being at most 1000 microns.

20. The strip of claim 16, wherein the one or more grains of crystalline material are oriented in a first direction, and wherein the basal plane of the crystalline material is aligned with the plane of the strip based at least in part on the one or more grains of crystalline material oriented in the first direction.

Technical Field

The present invention relates generally to crystalline materials; and more particularly to converting polycrystalline material into crystalline material, such as single crystal material or large crystal material.

Background

Crystalline materials with large grains (e.g., as compared to grains of polycrystalline material) may have physical, optical, and chemical properties that provide benefits to a range of industries and products. For example, single crystal materials, such as sapphire (e.g., single crystal alpha-alumina), may have high thermal conductivity, a wide transmission wavelength range, enhanced electrical insulation, and high strength and wear resistance, especially at high temperatures. Sapphire and other similar materials may therefore be very useful in a variety of products and applications, such as optical devices (e.g., laser crystals, waveguides), electronic components (e.g., semiconductor devices, electronic substrates), and ceramics (e.g., scratch resistant electronic housings, watch crystals), among others.

Disclosure of Invention

The methods, devices, and materials of the present disclosure have several novel and innovative aspects. This summary provides some examples of these novel and innovative aspects, but this disclosure may include novel and innovative aspects not included in this summary.

A method of manufacture is described. The method may include heating a first volume of ribbon using a first heat source, the ribbon comprising a polycrystalline material; and simultaneously heating a second volume of the ribbon while the ribbon is moving relative to at least a second heat source using the second heat source and using the first heat source, the second volume being within the first volume, wherein the heating using the first heat source and the second heat source converts at least a portion of the polycrystalline material of the ribbon within the second volume into a crystalline material comprising one or more grains that are larger than the plurality of grains of the polycrystalline material.

An apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are executable by a processor to cause the apparatus to heat a first volume of a ribbon using a first heat source, the ribbon comprising a polycrystalline material; and simultaneously heating a second volume of the ribbon while the ribbon is moving relative to at least a second heat source using the second heat source and using the first heat source, the second volume being within the first volume, wherein the heating using the first heat source and the second heat source converts at least a portion of the polycrystalline material of the ribbon within the second volume into a crystalline material comprising one or more grains that are larger than the plurality of grains of the polycrystalline material.

Another apparatus may include a tool for heating a first volume of a ribbon using a first heat source, the ribbon comprising a polycrystalline material; and means for simultaneously heating a second volume of the ribbon while the ribbon is moving relative to at least the second heat source, the second volume being within the first volume, using the second heat source and using the first heat source, wherein the heating using the first heat source and the second heat source converts at least a portion of the polycrystalline material of the ribbon within the second volume to crystalline material comprising one or more grains that are larger than the plurality of grains of the polycrystalline material.

In some examples of the methods and apparatus described herein, simultaneously heating the second volume using the second heat source may comprise heating at least the first surface of the ribbon using the first heat source, wherein heating at least the first surface of the ribbon heats the first volume of the ribbon; and simultaneously heating a second surface of the strip, the second surface being different from the first surface, wherein the polycrystalline material is convertible from the first surface of the strip to a crystalline material and extends from the first surface to a first depth of the strip.

In some examples of the methods and apparatus described herein, simultaneously heating the second volume using the second heat source may include scanning a second volume of the ribbon with the second heat source while heating the first and second volumes by the first heat source.

Some examples of the methods and apparatus described herein may further include operations, features, tools, or instructions for depositing one or more seed crystals on the polycrystalline material of the ribbon prior to the simultaneous heating using the first and second heat sources, wherein the orientation of the crystalline material may be based on the shape of the one or more seed crystals or the orientation of the one or more seed crystals, or both.

Some examples of the methods and apparatus described herein may further include operations, features, tools, or instructions for moving the strip relative to the second heat source at a speed of at least 0.2 inches per minute.

In some examples of the methods and apparatus described herein, the first heat source comprises a convective heat source or a first radiant heat source, or a combination thereof, for heating at least the first volume. In some examples of the methods and apparatus described herein, the second heat source may comprise a second radiant heat source for irradiating the second volume with photons, wherein the first volume may be larger than the second volume.

In some examples of the methods and apparatus described herein, the first heat source may comprise at least one of a flame, an oven, a furnace, or a microwave, and the second heat source may comprise at least one of a laser or a focused infrared source.

Some examples of the methods and apparatus described herein may further include operations, features, tools, or instructions for heating a first volume of the ribbon using a third heat source and simultaneously heating a second volume of the ribbon using a fourth heat source while the ribbon is moving relative to at least a fourth heat source, the first volume comprising a first subset of polycrystalline material and a second subset of crystalline material, the second volume being within the first volume, wherein heating using the third heat source and the fourth heat source converts at least a portion of the first subset of the polycrystalline material of the ribbon within the second volume to crystalline material, the crystalline material comprises one or more grains that are larger than the plurality of grains of polycrystalline material, and wherein the depth of crystalline material of the ribbon may be increased based on simultaneous heating using a third heat source and a fourth heat source.

In some examples of the methods and apparatus described herein, heating using the first and second heat sources may convert at least a portion of the polycrystalline material of the ribbon within the second volume to the crystalline material when the ribbon is in the solid state.

In some examples of the methods and apparatus described herein, the polycrystalline material of the ribbon may be at least partially sintered.

A manufacturing apparatus may include a support member for supporting a ribbon comprising a polycrystalline material; a moving means for moving the strip; a first heat source for heating a first volume of the ribbon; and a second heat source for simultaneously heating a second volume of the ribbon within the first volume simultaneously heated by the first heat source, the moving component configured to move the ribbon relative to at least the second heat source, wherein the first heat source and the second heat source are configured to convert at least a portion of the polycrystalline material of the ribbon into a crystalline material comprising one or more grains larger than the plurality of grains of the polycrystalline material based on heating the first volume and the second volume.

In some examples, the first heat source may be positioned to apply heat to at least a first surface of the ribbon, and the second heat source may be positioned to apply heat to a second surface of the ribbon different from the first surface, wherein the polycrystalline material may be converted from the first surface of the ribbon to a crystalline material and extend from the first surface to a first depth of the ribbon.

In some examples, the first heat source may be positioned to apply heat to at least a first surface of the ribbon, and the second heat source may be positioned to apply heat to the first surface of the ribbon, wherein the polycrystalline material may be converted from the first surface of the ribbon to a crystalline material and extend from the first surface to a first depth of the ribbon.

In some examples, the second heat source comprises an radiant heat source configured to scan a second volume of the ribbon using a raster pattern or a scanning pattern, or both.

In some examples, the apparatus includes a tension member for applying tension to the ribbon to change the shape of the ribbon when the first volume and the second volume are heated simultaneously.

A ribbon may include a first volume comprising polycrystalline material, the first volume extending from a first side of the ribbon to a first depth of the ribbon; and a second volume comprising crystalline material extending from a second side of the ribbon opposite the first side of the ribbon to a second depth of the ribbon, the crystalline material having a grain size of at least 100 microns and comprising one or more grains larger than the plurality of grains of polycrystalline material, wherein the second depth is at least 1 micron.

In some examples, the polycrystalline material comprises a polycrystalline ceramic material, a polycrystalline metallic material, or a semiconductor material, and the crystalline material comprises a sapphire material or a single crystal material.

In some examples, the crystalline material may have a grain size with a lateral dimension of at least 1 millimeter and a longitudinal dimension of at least 1 millimeter.

In some examples, the second depth of the second volume may extend to about a thickness of the tape, the thickness of the tape being at most 1000 microns.

In some examples, the one or more grains of crystalline material may be oriented in a first direction, wherein a basal plane (basal plane) of the crystalline material may be aligned with a plane of the ribbon based on the one or more grains of crystalline material oriented in the first direction.

Drawings

Fig. 1 illustrates an example of an apparatus supporting solid state conversion of polycrystalline material according to examples disclosed herein.

Fig. 2 illustrates an example of a manufacturing scheme supporting solid state conversion of polycrystalline material according to examples disclosed herein.

Fig. 3A and 3B illustrate examples of ribbons associated with solid state conversion of polycrystalline material according to examples disclosed herein.

Fig. 4A and 4B illustrate cross-sections of a ribbon associated with solid state conversion of polycrystalline material according to examples disclosed herein.

Fig. 5 illustrates an example of a cross-section of a ribbon associated with solid state conversion of polycrystalline material according to examples disclosed herein.

Fig. 6 illustrates a flow diagram illustrating a method of supporting solid state conversion of polycrystalline material according to examples disclosed herein.

Detailed Description

Relatively large crystalline materials, such as sapphire (e.g., single crystal alpha-alumina), have attracted industrial and research interest due to their unique properties and applications. For example, sapphire may have better performance than other materials (e.g., compared to polycrystalline alumina (PCA) having the same chemistry and crystalline phase) because sapphire may not have as many grain boundaries. Other processes for preparing or manufacturing sapphire may include dipping a seed crystal into a melt and continuously pulling the material to form a crystal. However, this process and other processes for making relatively large crystal materials (e.g., sapphire) are both expensive and slow.

In particular, some manufacturing techniques may require extended time, pretreatment processes, or both to obtain relatively large crystalline materials. As one example, solid state sapphire fabrication techniques (e.g., for High Pressure Sodium (HPS) lamps or HPS light applications) may be included in the process of H-containing₂Heating the PCA at elevated temperatures (e.g., above 1800 ℃). Abnormal Grain Growth (AGG) may occur by evaporation from self-contained magnesium oxide (MgO) or by addition of other dopants, and grain boundaries having some mobility may nucleate and migrate, thereby forming sapphire crystals. Such a process may allow sapphire to be manufactured by converting preformed PCA, but such a manufacturing process may take hours (e.g., more than 10 hours) to complete. In addition, multiple AGG events may occur because high temperatures may act on large areas of PCA. Thus, the sapphire formed by these processes is typically composed of a plurality of large grains, and small (e.g., 15-50 micrometers (μm)) unconverted grains are trapped in the large grains.

In other examples, a heat source may be used to solid state convert PCA (e.g., a PCA tube) to sapphire. However, these techniques may require pre-treatment of the PCA prior to treatment to reduce MgO content (e.g., PCA tubes may require less than 100 parts per million (ppmw), in some cases less than 50ppmw, of MgO prior to treatment). These pretreatment techniques for reducing the MgO content (e.g., prior to sapphire manufacture using a localized heat source) increase manufacturing costs and also require extended time. For example, a PCA tube conversion may require 10 hours of heat source treatment to avoid thermal shock. Furthermore, these and other techniques for converting PCA to sapphire may not be able to control the position or orientation of the conversion (e.g., control the thickness of the converted sapphire). Accordingly, improved techniques may be needed to reduce the time and cost of manufacturing sapphire and other crystalline materials with large grains.

The novel techniques and novel apparatus described herein can efficiently produce relatively large crystalline materials, such as single crystal materials, from strips or sheets of polycrystalline materials (e.g., PCA). In particular, various aspects of the present disclosure may include processing the strip or sheet to convert the polycrystalline material into one or more grains of large crystal material or single crystal material (e.g., sapphire), which may be accomplished relatively quickly and reduce manufacturing costs.

The techniques may include simultaneously heating a ribbon or sheet of polycrystalline material using multiple heat sources, wherein at least a portion of the ribbon or sheet may be located in a general region heated by a first heat source (e.g., flame, furnace, oven, microwave) while simultaneously being heated in the general region by a second heat source that may be more concentrated, localized, or focused (e.g., laser, focused Infrared (IR)) within a limited region. In some cases, the localized heat source may scan across the strip as the strip is heated by the first heat source. In some examples, there may be relative motion between the ribbon and one or more heat sources (e.g., the ribbon may move through a volume heated by a first heat source as a particular region of the ribbon is scanned by a localized heat source). In any case, simultaneous heating by two or more different heat sources can initiate and drive grain growth and produce at least large grains on at least one surface of the treated strip/sheet.

In some examples, the techniques may use sintered (or at least partially sintered) solid polycrystalline tapes or sheets, or solid tapes or sheets rolled from thicker materials. The tape or sheet may have a relatively small thickness (e.g., 40 μm) compared to the PCA tube or other material, and the tape or sheet may also have no length or width limitations. Furthermore, the tape may be flexible and may allow for various manufacturing techniques, such as a roll-to-roll process. Furthermore, the strip or sheet may not have any composition or content limitations (e.g., MgO content of the strip) prior to processing using the described techniques. For example, a strip of polycrystalline material may contain 500ppmw MgO, and the strip may not require pretreatment (e.g., heat treatment or other processes) to reduce the MgO content. Thus, the techniques may advantageously reduce the processing time and cost of manufacturing large crystal materials.

The techniques may also convert the polycrystalline material of the ribbon or sheet at higher speeds, where the polycrystalline material may be converted at speeds of 0.2 inches/minute or higher (e.g., 2 inches/minute, 20 inches/minute, etc.), thereby enabling processing of the ribbon or sheet of polycrystalline material in much shorter times (e.g., on the order of seconds and minutes rather than hours) than other techniques. In some aspects, the conversion of polycrystalline material to larger crystalline material (e.g., sapphire) may generally be controlled such that the larger crystalline material is fabricated from the surface of the ribbon or sheet (e.g., to a particular depth). In other cases, the conversion of polycrystalline material to crystalline material with large grains (e.g., sapphire) may be achieved throughout the thickness of the strip/sheet. The large grains of the treated material may be oriented in a first direction such that the basal plane (the plane perpendicular to the major axis in the crystal system) of the treated material may be aligned with the surface of the ribbon. Further, the process may be a roll-to-roll process or a roll-to-sheet (e.g., singulated sheet) process.

After processing using the described techniques, tapes comprising crystalline materials having relatively large grains may be used in a variety of applications, including transparent scratch-resistant handset housings, planar waveguides, laser crystals, creep-resistant ceramics, creep-resistant metals, electronic substrates, superconductor substrates, high temperature ceramic superconductors, ionic conductors, and the like. It is noteworthy that although some examples of the present disclosure are described with reference to converting alumina ceramics to large crystal materials (e.g., converting PCA to sapphire), the present disclosure is not limited to these materials. For example, the processing of the strip or sheet may not be limited to crystalline ceramics, but may also be used for crystalline metals, semiconductor materials, or other materials.

Features of the present disclosure are first described in the context of the manufacturing apparatus described with reference to fig. 1. The features of the present disclosure are further described in the context of the processing techniques described with reference to fig. 2-6, processed strips comprising crystalline material, cross-sectional views and flow charts of aluminum oxide strips.

Fig. 1 illustrates an example of an apparatus 100 supporting solid state conversion of polycrystalline material according to examples disclosed herein. The apparatus 100 may include a first heat source 105 and a second heat source 110 that may be used to apply heat to a ribbon 115 comprising a polycrystalline material 120 (e.g., PCA). The apparatus 100 may be configured to process the ribbon 115 to convert the polycrystalline material 120 of the ribbon 115 into a crystalline material 125 (e.g., a relatively large-grained crystalline material, a single crystalline material, a sapphire material, etc.), the crystalline material 125 having one or more grains larger than the grains of the polycrystalline material 120. In some examples, the device may include a moving member 155, or a tension member 160, or a support member 165, or any combination thereof.

Processing the strip material 115 by the apparatus 100 may include applying energy (e.g., individually, simultaneously) from multiple heat sources (e.g., the first heat source 105 and the second heat source 110) to the strip material 115.

In some examples, first heat source 105 may be an example of a heat source that facilitates heat transfer by convection or by radiation (e.g., a convection-type heat source, a radiant-type heat source), or both. For example, the first heat source 105 may be an example of an oven, flame, torch, or burner that applies heat to the ribbon 115, where the first heat source 105 may heat the first volume 130 of the ribbon 115. The first heat source 105 may also heat a volume 140 (e.g., including an atmosphere surrounding the ribbon 115) that is larger than the first volume 130, wherein the volume 140 may include (e.g., include) at least the first volume 130 of the ribbon 115. By way of example, the first heat source 105 may be an example of a furnace, microwave, oven, or the like that heats the first volume 130 of the ribbon 115. Thus, the first heat source 105 may heat the ribbon 115 throughout the thickness of the ribbon 115.

The first heat source 105 of the apparatus 100 may be located in one or more different positions, orientations, or vicinities relative to the ribbon 115. For example, the first heat source 105 may be located opposite the first surface 150-a of the ribbon 115, such as when the first heat source 105 includes a flame or burner. The distance between the first heat source 105 and the ribbon 115 can also be controlled or configured so that the temperature at which the first volume 130 is heated can be controlled or varied (or both) to process the ribbon 115. Different orientations and positions of the first heat source 105 are possible. The first heat source 105 may be configured to control the temperature of at least the first volume 130 of the ribbon 115 (e.g., in response to or capable of compensating for the configuration of the second heat source 110). Further, first heat source 105 may include wires or other components of a device that generates heat.

The second heat source 110 may be an example of a localized or concentrated heat source that heats the second volume 135 of the ribbon 115, for example, the second volume 135 may be within the first volume 130 of the ribbon 115. Because first volume 130 may be heated by first heat source 105, second volume 135, which may be within first volume 130, may be heated simultaneously by first heat source 105 and second heat source 110. The simultaneous application of heat from the first and second heat sources 105, 110 at the second volume 135 may drive grain growth within the second volume 135 and convert the polycrystalline material 120 into a crystalline material 125 (e.g., a single crystal material) having relatively larger grains.

The second heat source 110 may be an example of a radiant heat source, such as a laser or focused IR, etc. The second heat source 110 may be configured to apply heat to a concentrated area or region on the surface 150 of the ribbon 115 (e.g., and extending to a depth of the ribbon 115 to heat a volume of the ribbon 115) using one or more patterns or schemes. Further, the second heat source 110 may be configured to control the temperature of the ribbon 115 in the second volume 135 (e.g., based on considerations or adjustments to the configuration of the first heat source 105). The second heat source 110 may be located at one or more different positions, orientations, and vicinities relative to the ribbon 115. For example, as shown by second heat source 110-a, second heat source 110-a may be located opposite second surface 150-b of ribbon 115. Alternatively, the second heat source 110 may be located opposite the first surface 150-a of the ribbon 115, as shown by second heat source 110-b. The second heat source 110 (e.g., second heat source 110-a, second heat source 110-b) may apply heat to the ribbon (e.g., to the second volume 135 of the ribbon 115) from one or more different angles and directions relative to the first surface 150-a or the second surface 150-b. In any case, the second heat source 110 may heat the second volume 135 of the tape 115 by irradiating the second volume 135. It is noted that other types of heat sources and additional heat sources are possible and contemplated, and the examples described herein should not be considered limiting.

Heating the second volume 135 of the ribbon 115 may include scanning the second heat source 110 across the ribbon 115, wherein the scanning may be performed according to a particular pattern. By way of example, the second heat source 110 may be an example of a laser, and the laser may be scanned across the web 115 using a raster pattern. Additionally or alternatively, the laser may form a broad beam (e.g., a sheet of light or other configuration) that may continuously heat different portions of the second volume 135 as the broad beam is scanned across the ribbon 115. In some examples, the broad beam may be scanned across the ribbon 115 while the second volume 135 is simultaneously heated by the first heat source 105. Thus, the second heat source 110 and the ribbon 115 may move relative to each other.

The described techniques for converting the material of the ribbon 115 may be short-term (transient), continuous, or static. For example, the ribbon may be moved or translated in a direction by the moving component 155 of the apparatus 100, wherein the moving component 155 may be configured to move the ribbon 115 (e.g., continuously according to a certain movement configuration, etc.). Additionally or alternatively, the ribbon 115 may be stationary and the apparatus 100 and/or heat source may be continuously moving relative to the ribbon 115. In other examples, the ribbon 115 and the apparatus 100 may move relative to each other. Further, the ribbon 115 may be moved relative to the first heat source 105, the second heat source 110, or both by the moving member 155. The moving member 155 may be a separate motor or a motor having one or more other components or other devices or examples of components thereof capable of moving one or both of the strip 115 or the device 100.

Moving the strip 115 relative to the apparatus 100 (or one or more heat sources) may cause grains to grow along the length of the strip 115 as the second volume 135 of the strip 115 is simultaneously heated by the heat sources, which may result in the production of an alumina strip having relatively large grains that completely cover at least one surface (e.g., completely cover the width of the strip).

Specifically, the first volume 130 and the second volume 135 may be dynamically varied based on the motion of the ribbon 115. In some examples, the first volume 130 and the second volume 135 may be advanced along the length of the ribbon 115 as the ribbon 115 moves (e.g., when the first heat source 105 is applied to the ribbon, and when the second heat source 110 is applied to the ribbon 115). Thus, one or more portions of the ribbon heated simultaneously by first heat source 105 and second heat source 110 may cause polycrystalline material 120 on at least first surface 150-a (and to some associated depth/volume of the ribbon) to transform into crystalline material 125 along the length of the ribbon 115.

In other words, a portion of the ribbon 115 within the second volume 135 may be heated by the first heat source 105 and the second heat source 110, driving grain growth at that portion. As the ribbon 115 moves, the portions of the ribbon 115 that are subjected to both the first and second heat sources 105, 110 may dynamically increase in the length direction of the ribbon 115 (e.g., the longitudinal direction of the ribbon), which may convert additional polycrystalline material 120 into crystalline material 125 while the ribbon 115 moves. Furthermore, as described in further detail below, the crystalline material 125 may be fabricated in a transverse direction of the ribbon 115. In one example, as the ribbon is heated by both the first heat source 105 and the second heat source 110, the crystallized material 125 may increase in size, for example, from the center of the ribbon 115 outward toward the edges of the ribbon 115.

The conversion of the polycrystalline material 120 into crystalline material 125 having grains larger than the grains of the polycrystalline material 120 generally occurs from a surface 150 of the ribbon 115 through a depth of the ribbon 115. For example, as described in further detail with reference to fig. 3B, 4A, and 4B, the polycrystalline material 120 may be converted in a volume of the ribbon 115 extending from the first surface 150-a to a first depth. In some cases, the conversion to the crystalline material 125 may occur on the same surface 150 (e.g., the first surface 150-a of the ribbon 115) to which the first heat source 105 is applied, such as where the first heat source 105 is a flame, torch, or burner. In other examples, the transformation to the crystalline material 125 on the surface 150a may be independent of the location, position, or orientation of one or both of the first heat source 105 or the second heat source 110. Thus, the processed ribbon 115 may include a portion or volume of polycrystalline material 120 (e.g., through the depth of the ribbon 115 from the second surface 150-b) and another portion or volume of crystalline material 125 having relatively larger grains (e.g., through the depth of the ribbon 115 from the first surface 150-a).

As an illustrative example of the conversion process performed by the apparatus 100, a polycrystalline alumina strip may be converted using a laser or other focused, localized heat source in addition to another heat source to produce an alumina strip having relatively large grains covering one surface 150. A propane torch flame (e.g., first heat source 105) may be used to heat the alumina strip from one side (e.g., corresponding to first surface 150-a), and a carbon dioxide (CO2) laser (e.g., second heat source 110) may be used to scan across the alumina strip from the other side (e.g., corresponding to surface 150-b) at approximately the same area or location. That is, the aluminum strip may be passed through a zone heated by a propane torch flame while the alumina strip is scanned with a CO2 laser. The temperature of the alumina strip may be controlled by both the first heat source 105 (e.g., a flame) and the second heat source 110(CO2 laser).

In this example, the starting material of the tape 115 (e.g., prior to processing using the apparatus 100) may comprise a fully sintered (or at least partially sintered) alumina tape (e.g., comprising Al)₂O₃). In some cases, the alumina strip may have a purity of 99.95% and a uniform polycrystalline microstructure. In some cases, the alumina strip may have a strip of greater than 99 percentRelative density, and the polycrystalline material 120 of the ribbon 115 may have a grain size of 1.5 microns. In some examples, the alumina strip may contain 500ppm MgO by weight. The alumina strip may be treated with this or a different weight content of MgO, and the alumina strip may not require pretreatment to reduce or change the MgO content. The ribbon 115 may also exclude, for example, dopants, such as silicon dioxide (SiO), on the surface of the ribbon 115₂)。

The ribbon 115 may be an example of an alumina ribbon ceramic, a flexible ceramic ribbon, or the like. For example, the ribbon 115 of the present example may be a 40 μm thick alumina ribbon and may be 1 inch wide by 4 inches long. However, other ribbon sizes are also contemplated. For example, the alumina strip may be wider than 1 cm (e.g., 2.5 cm wide, or may be wider than 10 cm, or wider than 30 cm). Likewise, the alumina strip may be longer than 1 cm (e.g., 5 cm, 10 cm, but may be as long as the area allows). Further, while the alumina strip may be 40 μm thick, it may be any thickness (e.g., between 20 and 1000 μm). It is also worth noting that while various aspects of the present disclosure are described with reference to a ribbon 115, a sheet (e.g., an alumina sheet) or other similar structure may also be used.

The laser beam (e.g., of second heat source 110) may, for example, have a diameter of 8 millimeters and a power of 88 watts (W). However, lasers with different powers and diameters may be used. In one example, the laser may be raster scanned (rastered) across the alumina strip at a speed of 4500 mm/sec, with a scan width of 60 mm. In another example, the laser may be continuously scanned across the width of the ribbon (e.g., instead of raster scanning) at a speed of 4500 mm/sec. At the end of the scan, the laser beam may be stepped (step) by 0.025 mm. In some examples, the effective laser travel speed along the length of the alumina strip may be 1.8 mm/sec, although different speeds are possible. In some cases, the laser may scan a 1.5 inch length of the ribbon in less than 30 seconds. The speed of the process performed by the apparatus 100 to convert the polycrystalline material 120 to the crystalline material 125 may be 0.2 inches per minute or more. For example, the ribbon may be moved at a speed of 2 inches per minute, 20 inches per minute, or 200 inches per minute. Thus, the alumina strip can be processed at a higher rate than other processes that consume hours of time.

As the alumina strip passes through the propane torch and the CO2 laser (e.g., second volume 135 is simultaneously heated by first heat source 105 and second heat source 110), large grains may be obtained that completely cover the first surface 150-a of the alumina strip. Thus, the treated ribbon 115 may include at least a portion of the crystalline material 125, the crystalline material 125 including one or more grains (e.g., large grains) that are larger than the grains of the polycrystalline material 120. The simultaneous application of the heat source may cause the polycrystalline material 120 to be converted to a single crystal material (e.g., sapphire). In some cases, the lateral dimension of the large grains may be greater than 500 μm. In some examples, the lateral dimension of the large grains may be as large as the lateral dimension of the ribbon. In some examples, the depth dimension of the large grains may be greater than 10 μm, and may be as deep as the thickness of the ribbon. Thus, the treated strip may be entirely a single crystal sapphire strip.

In some examples, tension may be used in (e.g., during or after) a method of converting a polycrystalline alumina strip to an alumina strip having relatively large grains completely covering one surface 150, wherein the tension may alter or transform the shape of the converted alumina strip. Here, tension member 160 may apply tension to one or more locations of ribbon 115. As an illustrative example, as the alumina strip passes through the first heat source 105 (e.g., a propane flame burner) and the second heat source 110 (e.g., a laser), tension may be controlled by applying weight at one end of the strip 115 while pulling the other end at a steady speed by the moving member 155 (e.g., a motor). In one example, tension member 160 may apply a weight of 200 grams to ribbon 115 while ribbon 115 may be pulled by moving member 155 at a rate of 2 inches per minute. Tension member 160 may apply tension to ribbon 115 while ribbon 115 (e.g., second volume 135) is simultaneously heated by first heat source 105 and second heat source 110. In other examples, tension member 160 may apply tension after ribbon 115 is simultaneously heated by first heat source 105 and second heat source 110.

In some examples, the ribbon 115 may be processed multiple times, which may increase the amount of crystalline material (e.g., single crystal material) of the processed ribbon 115. For example, after the ribbon 115 is processed by the apparatus 100, resulting in a ribbon having relatively large crystalline material (e.g., crystalline material 125) along the length of the ribbon 115, one or more heat sources, such as the first heat source 105 or the second heat source 110, or both, may be used to apply heat to the ribbon 115, such as a second application. In this case, the additional processing of the ribbon 115 may result in a greater amount of crystalline material 125 having large grains being formed along the length of the ribbon 115 (e.g., the sapphire material increases in depth from the first surface 150-a).

More specifically, additional processing by applying the first heat source 105 or the second heat source 110 (e.g., to the second volume 135), or both, may result in some portion or subset of the polycrystalline material 120 (e.g., the portion or subset remaining after the initial processing of the ribbon 115) being converted into the crystalline material 125. As described with reference to fig. 4A and 4B, the depth of the crystallized material 125 may be increased due to multiple (e.g., sequential) additional treatments of the ribbon. The ribbon 115 may be processed any number of times, which in some cases may result in the production of a ribbon 115 of crystalline material 125 (e.g., containing no or trace amounts of polycrystalline material 120). In some examples, the second volume 135 of the ribbon 115 may be heated multiple times simultaneously by the first heat source 105 or the second heat source 110, or both (e.g., additional scans of the second heat source 110). Additionally or alternatively, the second volume 135 of the ribbon 115 may be heated simultaneously by a third heat source (e.g., similar to the first heat source 105) and a fourth heat source (e.g., similar to the second heat source 110). In some cases, the first heat source 105, the second heat source 110, the third heat source, and the fourth heat source may be the same or different types of heat sources. Additionally or alternatively, the ribbon 115 may be processed in a different direction or orientation than the initial processing. For example, the strip material 115 may be processed once, then flipped over and processed again.

The support member 165 of the apparatus 100 may, for example, hold the ribbon 115 prior to processing. The support member 165 may be an example of a reel or similar device that holds the ribbon 115 prior to processing and potentially provides some rigidity to the processing. Additionally or alternatively, the processing of the strip material 115 may be a roll-to-roll process, and the second support member may be used to hold the strip material 115 after the strip material 115 is processed. In other cases, the treated strip 115 may be singulated into two or more portions of crystalline material 125 having large grains.

One or more aspects performed by the apparatus 100 may result in an alumina strip 115 having large grains that completely covers at least one surface 150. The treated strip 115 may have a shape or form factor that allows for a variety of applications and uses, and the alumina strip produced by the apparatus 100 may be rolled. The fabrication techniques and apparatus 100 may provide increased speed and reduced fabrication costs, among other benefits. For example, a strip of alumina (or a sheet of alumina or a sheet of PCA) converted to a relatively large-grained crystalline material (e.g., sapphire) can improve many properties of the alumina, such as scratch resistance, thermal conductivity, optical transmittance, and the like. Further, the conversion of the alumina strip may be performed while the strip is in a solid state (e.g., without melting the strip 115).

The fabrication techniques can produce long single crystal ribbons or sheets of various compositions. The technique can also produce large-size, thin alumina strip with large grains that completely cover at least one surface. This form factor, as well as the superior properties of the large crystal materials and single crystal materials described herein, are unique in the thin ceramic substrate industry. Thus, the treated ribbons 115 described herein can provide one or more advantages in various commercial applications, such as substrates for electronic devices, covers for electronic devices (e.g., phones, watches), insulators, and the like. In addition, the techniques may reduce manufacturing costs and may also eliminate the need for high temperature furnaces and/or controlled atmospheres. The process may be continuously performed at a speed of at least 0.2 inches per minute, and a potential roll-to-roll process may further reduce manufacturing costs. In some cases, the processes and apparatus can produce thin single crystal strips and/or sheets of increased length (e.g., several meters in length).

Fig. 2 illustrates an example of a manufacturing scheme 200 that supports solid state conversion of polycrystalline material according to examples disclosed herein. The manufacturing scheme 200 may be performed by an apparatus, such as the apparatus 100 described with reference to fig. 1. For example, the manufacturing scheme may include a ribbon 215 (e.g., an alumina ribbon) comprising a polycrystalline material 220, which may be an example of the ribbon 115 described with reference to fig. 1.

The manufacturing scheme 200 may be used to treat the strip 215 using a first heat source (e.g., flame, torch, furnace, oven) that may heat a first volume 230 of the strip and using a second heat source that simultaneously heats a second volume 235 of the strip 215 within the first volume 230. Simultaneously heating at least the second volume 235 of the ribbon 215 may convert the polycrystalline material 220 into a crystalline material 225, the crystalline material 225 having one or more grains larger than the grains of the polycrystalline material 220. In some examples, the crystalline material 225 may be a single crystal material. In some cases, the crystalline material 225 may be a sapphire material.

The manufacturing scheme 200 may include the use of nucleation crystals 250 (e.g., seeds) deposited on the ribbon 215, wherein one or more different orientations of the crystalline material 225 may be obtained by utilizing the nucleation crystals 250. By using the manufacturing scheme 200, an alumina strip having large grains covering at least one surface of the strip 215 can be manufactured.

As described herein, the application of multiple heat sources to the ribbon 215 may drive the grains of relatively larger crystalline material (e.g., crystalline material 225) on the surface of the ribbon 215 to grow to a depth of the ribbon 215.

The relatively large crystalline material may have a particular orientation on the ribbon 215. For example, one or more grains of relatively large crystalline material may have an orientation such that the basal plane of the large crystalline material is aligned or nearly aligned with the plane or surface of the ribbon 215. In some cases, the nucleating crystals 250 may be used to initiate grain growth of the ribbon 215. For example, the nucleating crystals 250 may be deposited on the ribbon 215, and when the volume of the ribbon 215 including the nucleating crystals 250 is within the second volume 235 (e.g., heated simultaneously by multiple heat sources), the nucleating crystals 250 may initiate grain growth of the crystalline material 225 having large grains. In other embodiments, the crystals may be otherwise aligned and/or the system may not include a basal plane.

Further, as illustrated in manufacturing scheme 200, growth of crystalline material 225 may begin at or near the location of nucleation crystals 250. Subsequently, grain growth may diffuse to the edges of the strip 215 as the strip 215 moves relative to the heat source (or, alternatively, as the heat source moves relative to the strip). Specifically, the size of the crystalline material 225 may increase in both the transverse dimension and the longitudinal direction of the ribbon 215 (corresponding to the length of the ribbon 215) as successive portions of the ribbon 215 are dynamically positioned within the second volume 235 that is simultaneously heated. In some examples, the crystalline material 225 having large grains may cover the surface of the strip material 215 and may have the same width as the width 255 of the strip material 215.

Some compositions and orientations of crystalline material 225 may be controlled or enhanced by using nucleation crystals 250 (e.g., by forced nucleation of seed crystals), and different crystalline shapes or structures may be used to nucleate crystals 250. As one example, the nucleating crystals 250 may have a hexagonal crystal orientation. In other examples, alternative hexagonal orientations 260 may be used to nucleate crystals 250. Additionally or alternatively, cubic crystal orientation 265 may be used to nucleate crystals 250. In some cases, alternating cubic orientations 270 may be used to nucleate crystals 250. Other shapes, sizes, and orientations of the nucleating crystals 250 may be used, and the examples should not be considered limiting. The shape, orientation, or structure of the nucleating crystals 250 may change the orientation of the crystalline material 225 formed on the surface and within the volume of the ribbon 215.

Fig. 3A and 3B illustrate an example of a ribbon 300 involving solid state conversion of polycrystalline material.

For example, fig. 3A may show a surface of a strip material 300 that has been treated using the techniques described herein. More specifically, the strip material 300 may illustrate an example of an aluminum oxide strip material, such as the strip material 115 or the strip material 215 described with reference to fig. 1 and 2, that is processed by simultaneously heating the strip material 300 using a first heat source (e.g., flame, oven) and a second heat source (e.g., laser). In some examples, the ribbon 300 may include other materials, such as crystalline metals, semiconductor materials, or other ceramic materials.

Due to the simultaneous heating, the surface of the ribbon 300 may accordingly include relatively large crystalline material. In particular, the ribbon 300 may include a relatively large crystalline material or a single crystal material on its surface. The treated region 305 of the tape 300, to which at least a second heat source (e.g., a laser, focused IR or other radiant heat source) is applied, may have a higher transparency than the untreated region 310 of the tape 300. The treatment area 305 (e.g., laser treatment area) may accordingly include one or more large grains 315 that have been formed on the surface of the strip material 300. Furthermore, within the processing region 305, there may be regions 320 with even higher transparency. In some examples, the size of the area 320 may be similar to the size of the area of the strip 300 heated by the first heat source, such as in examples using a flame or torch as the first heat source as described herein.

Fig. 3B may illustrate an example of a cross-section 301 of a ribbon 300. For example, a cross-section 301 of the processed ribbon 300 may illustrate one or more portions of the region 320 described with reference to fig. 3A. As described herein, the large grains 315 may be located on a surface 325 of the strip material 300. The large grains 315 may correspond to the volume of the strip material 300 starting from the surface 325 of the strip material 300 and extending to a depth of the strip material 300. For example, the depth of the large grains 315 from the surface 325 may be at least 10 μm. In some examples, the large grains 315 may have a dimension that is at least several hundred microns long (e.g., laterally along the surface 325 of the ribbon 300), and may also extend longitudinally several hundred microns (e.g., corresponding to the length of the ribbon 300). However, the volume of the large grains 315 may have different sizes in one or more directions.

The cross-section 301 also illustrates the polycrystalline material 330 of the ribbon 300 having a plurality of grains 335, wherein one or more large grains 315 (e.g., of crystalline material) may be larger than the grains 335 of the polycrystalline material 330. Grains 335 may have varying sizes and may have different orientations (e.g., random orientations) from one another. In contrast, a large grain 315 may have the same orientation as another large grain 315, or may have an orientation corresponding to a hexagonal or triclinic crystal structure. In some examples, the large grains 315 may be an example of a single crystalline material. The single crystal material may not have grain boundaries (e.g., other than surface 325), and may extend across the width of the ribbon. Further, in some examples, the single crystal material may have an atomic structure that periodically repeats across the volume of the large grains 315.

In some examples, using multiple heat sources (e.g., laser processing and additional flame heating) to simultaneously heat the strip 300 may result in different microstructures when processed under different conditions. For example, the original microstructure of the strip 300 may have some porosity after sintering. In the microstructure shown in cross-section 301 (e.g., upon simultaneous application of heat by two different heat sources), large crystals (e.g., the large grains 315) may be formed. In some aspects, the grains 335 of the polycrystalline material 330 are larger than the initial size of the polycrystalline grains (e.g., corresponding to the untreated regions 310) over the volume of the untreated ribbon.

In some cases, by applying the same laser treatment to the alumina strip 300 without the first heat source (e.g., applying heat using only the second heat source), the microstructure of the strip 300 may become denser without too much grain growth. Alternatively, the treatment is performed by applying a high power laser (e.g., as a second heat source) to the alumina strip 300, and in the absence of the first heat source, some of the grains may grow to a size slightly larger than the grains 335 of the polycrystalline material 330. This grain growth may be a result of the higher temperature obtained due to the increased power of the laser. In some cases, there may be no large crystals present by laser treatment alone, where the simultaneous addition of heat from a first heat source (e.g., flame, oven, etc.) may result in the formation of large crystals, even if no change is observed with heating using only the first heat source.

In some examples, large grains 315 may be oriented such that basal planes (0001 or 001) of crystalline material (e.g., sapphire crystals) are aligned in the plane of ribbon 300. The opposite side of the strip 300 may have small grain size polycrystals (e.g., polycrystalline material 330; average grain size less than 100 μm on the surface, e.g., on the order of less than 80 μm, e.g., less than 50 μm, e.g., less than 20 μm, e.g., less than 10 μm, e.g., 5 μm or less average grain size) on the surface of the opposite side (open size) of the strip 300), which may correspond to unoriented polycrystalline alpha-alumina. In contrast, the average grain size of the crystalline material may be at least μm, such as at least 150 μm, such as at least 200 μm, at least 500 μm, as measured on the surface of the strip 300. In some embodiments, the lateral dimension of the grain size of one or more grains of crystalline material may be at least 1 millimeter, and the longitudinal dimension of the grain size is at least 1 millimeter. As the heat source softens and allows the larger grain size portion of the strip 300 to form, support to the sintered smaller grain size portion of the strip 300 may hold the strip 300 together.

Fig. 4A and 4B illustrate examples of cross-sections 400 and 401 of treated ribbon associated with solid state conversion of polycrystalline material according to examples disclosed herein. Cross-sections 400 and 401 show an aluminum oxide strip 405 that has been treated one or more times according to the techniques described herein. The strip 405 may be an example of an alumina strip (e.g., PCA, alumina strip ceramic), such as the strip 115, the strip 215, or the strip 300 described with reference to fig. 1, 2, 3A, or 3B, that has been processed by simultaneously heating the strip using a first heat source and a second heat source. In some examples, the strip material may be processed by a manufacturing apparatus (e.g., apparatus 100), as described with reference to fig. 1.

In some examples, the aluminum oxide strip 405 may be scanned multiple times by a localized heat source (e.g., a laser) while being simultaneously heated using another heat source (e.g., a furnace, flame, etc.). Specifically, fig. 4A shows a cross-section of an alumina strip 405 that has been treated once using the described technique (e.g., by a CO2 laser and a propane torch flame). At least a portion of ribbon 405 may have been heated using a first heat source and a second, different heat source such that the large grains completely cover at least one surface 410 (e.g., surface 410-a) of ribbon 405.

The treated ribbon 405 may include a first volume 415-a comprising polycrystalline material and a second volume 420-a comprising crystalline material having one or more grains larger than the grains of the polycrystalline material. The first volume 415-a may extend from the surface 410-b to a first depth of the ribbon 405. Similarly, the second volume 420-a may extend from the surface 410-a to a second depth of the ribbon 405. The depth of the second volume 420-a (e.g., comprising large crystalline material) may be at least 1 μm based on the processing of the ribbon 405 using multiple heat sources simultaneously. However, as shown, the second volume 420-a may be at least 10 μm deep. In other cases, the depth of the second volume 420-a (e.g., after one pass of processing) may be equal to or approximately equal to the thickness of the ribbon 405 (where the depth of the first volume 415-a of polycrystalline material may be zero or near zero).

The strip 405 may be processed one or additional times and fig. 4B shows an example of an alumina strip (e.g., the strip 405) that has been scanned, for example, four times (e.g., by a CO2 laser while being heated with a propane torch flame). The thickness of the large grains contained in the second volume 420-a of the ribbon 405 may increase in size due to the additional heat treatment. In particular, after being processed one or additional times, at least a first subset of polycrystalline material from the first volume 415-a may be converted to large crystal material (e.g., crystalline material). Thus, the size (e.g., depth) of the crystalline material of the second volume 420-a may be increased.

Due to the additional processing, and as shown in cross-section 401, the first volume 415-b may be smaller than the first volume 415-a, and the second volume 420-b may be larger than the second volume 420-a. Here, the depth of the second volume 420-b may be greater than the depth of the second volume 420-a, wherein the depth of the second volume 420-b may be, for example, between 15 μm and 20 μm. In some cases, the depth of the second volume 420-b (e.g., after one or more additional processing operations) may be the same or nearly the same as the thickness of the ribbon 405 (where the depth of the first volume 415-b of polycrystalline material may be zero or nearly zero). The increase in depth of the second volume 420-b containing large crystal material may follow the transition parabolic law of grain growth.

Fig. 5 illustrates an example of a cross-section of a ribbon 500 associated with solid state conversion of polycrystalline material according to examples disclosed herein. The cross-section of the strip may be an example of an alumina strip (e.g., PCA, alumina strip ceramic) that has been heat treated simultaneously by using a first heat source and a second heat source, such as the strip 115, the strip 215, the strip 300, or the strip 405 described with reference to fig. 1, 2, 3A, 3B, 4A, or 4B.

A cross-section of the ribbon 500 may show the large crystals 505 that have formed after processing using the described techniques. In addition, the cross-section of ribbon 500 shows surface 510 of large crystal 505 and edge 515 (e.g., corner) of large crystal 505. Surface 510 may correspond to a flat surface of aluminum oxide strip 500. As shown by surface 510, there may be a plurality of rounded hexagonal platforms (terraces) 520 (e.g., hexagonal platforms 520-a and 520-b) of large crystal 505. These hexagonal platforms 520-a and 520-b show that the basal orientation of the large crystals 505 can be aligned with the plane of the alumina strip 500. Further, the surface 510 of the large crystal 505 may show a plurality of partially rounded hexagons.

Here, ledges (ridges) and plateaus of the large crystal 505 may provide surface diffusion that minimizes surface energy. The hexagonal plateaus 520 (as well as partially rounded hexagons) may reflect the basic crystal structure (hexagonal/triclinic) of the large crystals 505 and show that the basal planes may be nearly in the plane of the alumina strip 500. Such an orientation may be advantageous, for example, if the structure is used for optical purposes where light is transmitted perpendicular to the plane of the strip (e.g., for a telephone or flat-panel touch screen). Other orientations of the large crystals 505 may be achieved by the techniques described herein.

Fig. 6 illustrates a flow chart showing a method 600 of supporting solid state conversion of polycrystalline material according to examples disclosed herein. The operations of method 600 may be performed by a manufacturing system or one or more controllers associated with a manufacturing system. In some examples, the operations of method 600 may be implemented by, inter alia, an apparatus such as apparatus 100 described with reference to fig. 1. In some examples, one or more controllers may execute a set of instructions to control one or more functional elements of a manufacturing system or apparatus to perform the described functions. Additionally or alternatively, one or more controllers can perform various aspects of the described functionality using dedicated hardware.

At 605, the method 600 may include heating a first volume of the ribbon using a first heat source, the ribbon comprising a polycrystalline material. 605 may be performed according to the methods described herein. 605 may be implemented by an apparatus, such as apparatus 100 or 200 described with reference to fig. 1 and 2.

In 610, the method 600 may include simultaneously heating a second volume of the ribbon within the first volume using a second heat source and using a first heat source while the ribbon is moving relative to at least the second heat source, wherein the heating using the first heat source and the second heat source converts at least a portion of the polycrystalline material of the ribbon within the second volume into a crystalline material comprising one or more grains larger than the plurality of grains of the polycrystalline material. 610 may be performed according to the methods described herein.

In some examples, an apparatus described herein may perform one or more methods of manufacture, such as method 600. The apparatus may include features, tools, or instructions (e.g., a non-transitory computer-readable medium storing instructions executable by a processor) for heating a first volume of ribbon using a first heat source, the ribbon comprising a polycrystalline material. The apparatus may include features, means, or instructions for simultaneously heating a second volume of the ribbon within the first volume using a second heat source and using a first heat source while the ribbon is moving relative to at least the second heat source, wherein the heating using the first heat source and the second heat source converts at least a portion of the polycrystalline material of the ribbon within the second volume into a crystalline material comprising one or more grains larger than the plurality of grains of the polycrystalline material.

In some examples of the method 600 and apparatus described herein, the operation, feature, tool, or instruction to simultaneously heat the second volume using the second heat source may further comprise the operation, feature, tool, or instruction to simultaneously heat at least a first surface of the ribbon using the first heat source while heating a second surface of the ribbon different from the first surface, wherein heating at least the first surface of the ribbon heats the first volume of the ribbon, wherein polycrystalline material may be converted from the first surface of the ribbon to crystalline material and extend from the first surface to the first depth of the ribbon. In some examples of the method 600 and apparatus described herein, the operation, feature, tool, or instruction to simultaneously heat the second volume using the second heat source may further comprise the operation, feature, tool, or instruction to scan the second volume of the ribbon using the second heat source while the first volume and the second volume are heated by the first heat source.

Some examples of the methods 600 and apparatus described herein may also include operations, features, tools, or instructions for depositing one or more seeds on the polycrystalline material of the ribbon prior to heating using the first and second heat sources while heating, wherein the orientation of the crystalline material is based on the shape of the one or more seeds or the orientation of the one or more seeds, or both. Some examples of the method 600 and apparatus described herein may also include operations, features, tools, or instructions for moving the strip relative to the second heat source at a rate of at least 0.2 inches per minute.

In some examples of the methods 600 and apparatus described herein, the first heat source comprises a convective heat source or a first radiant heat source, or a combination thereof, for heating at least the first volume. In some examples of the method 600 and apparatus described herein, the second heat source comprises a second radiant heat source for illuminating a second volume with photons, wherein the first volume is larger than the second volume. In some examples of the method 600 and apparatus described herein, the first heat source comprises at least one of a flame, an oven, a furnace, or a microwave. In some examples of the method 600 and apparatus described herein, the second heat source comprises at least one of a laser or a focused IR source.

Some examples of the method 600 and apparatus described herein may also include operations, features, tools, or instructions for heating a first volume of the ribbon using a third heat source, wherein the first volume includes a first subset of the polycrystalline material and a second subset of the crystalline material. Some examples of the methods 600 and apparatus described herein may further include operations, features, tools, or instructions for simultaneously heating a second volume of the ribbon within the first volume using a fourth heat source and using a third heat source while the ribbon is moving relative to at least the fourth heat source, wherein the heating using the third heat source and the fourth heat source converts at least a portion of the first subset of the polycrystalline material of the ribbon within the second volume into a crystalline material comprising one or more grains larger than the plurality of grains of the polycrystalline material, and wherein the depth of the crystalline material of the ribbon is increased based on the simultaneous heating using the third heat source and the fourth heat source.

In some examples of the method 600 and apparatus described herein, heating using the first and second heat sources converts at least a portion of the polycrystalline material of the ribbon within the second volume to crystalline material when the ribbon is in the solid state. In some examples of the methods 600 and apparatus described herein, the polycrystalline material of the ribbon is at least partially sintered.

It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise altered, and that other implementations are possible. Furthermore, portions of two or more methods may be combined.

The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The terms "electronic communication," "conductive contact," "connection," and "coupling" may refer to a relationship between components that supports signal flow between the components. Components are considered to be in electronic communication with each other (or in conductive contact, connection, or coupling) if there are any conductive paths between the components that can support the flow of signals between the components at any time. At any given time, the conductive path between components that are in electronic communication with each other (or in conductive contact, connection, or coupling with each other) may be an open circuit or a closed circuit, based on the operation of the device that includes the connected components. The conductive path between the connection components may be a direct conductive path between the components, or the conductive path between the connection components may be an indirect conductive path, which may include intermediate components, such as switches, transistors, or other components. In some examples, signal flow between connected components may be interrupted for a period of time, for example, using one or more intermediate components, such as switches or transistors.

The description set forth herein in connection with the drawings describes example configurations, but is not intended to represent all examples that may be practiced or within the scope of the claims. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration," rather than "preferred" or "superior to other examples. The detailed description includes specific details to provide an understanding of the described technology. However, these techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the examples.

In the drawings, similar components or features may have the same reference numerals. In addition, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label, regardless of the second reference label.

The various illustrative blocks, components, and modules described in connection with the disclosure herein may be implemented or performed with a general purpose processor. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be embodied as a combination of computing devices.

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and embodiments are within the scope of the disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these. Features that perform a function may also be physically located at different locations, including being distributed such that some functions are performed at different physical locations. Further, as used herein, including the claims, "or" as used in a list of items (e.g., a list of items beginning with the phrase "at least one" or "one or more") means an inclusive list, e.g., a list of at least one of A, B or C means a or B or C or AB or AC or BC or ABC (i.e., a and B and C). Further, as used herein, the phrase "based on" should not be construed as referring to a closed set of conditions. For example, an exemplary step described as "based on condition a" may be based on condition a and condition B without departing from the scope of the present disclosure. In other words, the phrase "based on," as used herein, is to be interpreted in the same manner as the phrase "based, at least in part, on.

This description is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the present disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.