JP2011520746A - Glass structure having sub-micron and nano-sized band gap structure and manufacturing method thereof - Google Patents

Abstract

  Glass structures having sub-micron and nano-sized band gap structures and methods for fabricating the glass structures are provided. Creating a first glass structure with micrometer-scale features, and then allowing the first glass structure to function as a polarizer for visible and infrared light, Draw into a second glass structure with nanosized features.

Description

Cross-reference of related applications

  This application is based on the name of the invention named “Glass Structure Having Sub-Micron and Nano-Size Bandgap Structures and Method of Producing Same” in 2008. Claims the priority and benefit of US patent application Ser. No. 12 / 148,591, filed Apr. 21, Its content is trustworthy and is incorporated herein in its entirety by reference.

 The present invention relates to a method for producing submicron and nano-sized structures, in particular glass structures.

 Structures used as band gap structures on the millimeter and micrometer scale are manufactured using ceramic materials and various technologies. For example, one method of making such a micrometer scale structure is known as rapid prototyping. This is typically a technique that combines a computer and a layering process to produce the structure. The desired structural model is divided into layers of a predetermined thickness using a computer. Each layer of the structure is reconstructed by stacking, and the original part is reproduced. The final shape details and complexity depend on the thickness of the individual starting layers. The structure is then subjected to an organic binder burnout process and a final sintering process. There are several patents that describe this process. These include, for example, Patent Documents 1 and 2, the disclosures of which are incorporated herein by reference.

US Patent Application No. 5,738,817 US Patent Application No. 5,997,795

A method for producing submicron and nano-sized glass structures comprising:
A glass mixture containing glass powder and binder is distributed into one layer at a time to produce a predetermined structure;
Removing at least 75% of the binder from the predetermined structure during the binder combustion step;
Sintering the predetermined structure to produce a first glass structure having a predetermined cross-sectional area;
Drawing the glass structure into a second glass structure;
Having each process,
The second glass structure is at least one-tenth the predetermined cross-sectional area of the first glass structure, in some cases at least one-fifth, and in some cases at least one hundredth the size. A method is disclosed, characterized by having only a cross-sectional area. Preferably, said dispensing step comprises the step of dispensing a plurality of layers, each layer being deposited one layer at a time, and in some preferred embodiments these depositions are greater than 10. More preferably more than 20 layers may be included. In some preferred embodiments, the thickness of each layer can be less than 2 mm, more preferably less than 1 mm, and in some embodiments, less than 500 micrometers. In some embodiments, the drawing step has a cross-sectional area that is at least 1 / 500th of a predetermined cross-sectional area of the first glass structure, and in some cases at least 1 / 800th of the cross-sectional area. Two glass structures can be produced. Thus, this process allows the formation of a standing structure having dimensions of width, length, or diameter of about tens or hundreds of nanometers.

 In another aspect, a glass structure for polarizing light is disclosed, the glass structure comprising a single glass structure and a plurality of openings extending through the single glass structure, wherein the single glass structure includes: The located opening has a diameter of about 200 nanometers.

 Additional features and advantages of the invention will be set forth in the detailed description that follows and, in part, will be readily apparent to those skilled in the art from the description, or may be set forth in the detailed description and claims set forth below. It will be appreciated by implementing the invention described herein, including the scope and accompanying drawings.

 Both the foregoing summary and the following detailed description of the embodiments of the present invention are intended for purposes of illustration and description, and for understanding the nature and features of the present invention as set forth in the claims. It should be understood that it is intended to provide an overview or framework of The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention.

1 is a front view of a first single glass structure according to the present invention. FIG. FIG. 2 is an enlarged view of a part of the single glass structure of FIG. 1.

 Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

 In one exemplary embodiment, a glass mixture can be prepared that can be used to fabricate the predetermined structure 100 illustrated in FIGS. These structures can be fabricated using any method that can deposit or form structures having dimensions of a few millimeters or less. Preferred deposition techniques include, but are not limited to, techniques for dispensing using microdispensers such as rapid prototyping and micropens. For example, in one exemplary embodiment, a given structure 100 can be made using a rapid prototyping machine, whereby multiple layers of glass mixture are “printed”, with each layer Are printed one layer at a time, thereby producing a three-dimensional structure. The glass mixture can be any glass composition. For example, in some embodiments, the glass mixture can be a silica-based glass, such as a borosilicate glass. The glass mixture is preferably made of glass powder of the desired glass composition. The size of the glass in the glass powder is preferably in the micrometer range. The glass mixture also preferably includes an organic binder, which can be any suitable commercially available binder. The glass mixture is preferably 60-90% glass powder and 10-40% binder, more preferably 70-80% glass powder and 20-30% binder. Next, the consistency of the glass mixture is adjusted so that it is properly dispensed from the rapid prototyping machine.

 The glass mixture is then dispensed by machine to form the predetermined structure 100, as illustrated in FIGS. It should be noted that although the predetermined structures illustrated in FIGS. 1 and 2 are square / rectangular forms, any form may be “printed” and are within the scope of the present invention. Note that although the sub-structure or the precise dimensions of a given structure are not essential to the present invention, the given structure illustrated in FIGS. 1 and 2 is composed of a plurality of sub-structures of approximately 50 mm × 50 mm × 2 mm. I want to be. A plurality of 2 mm thick substructures are fused to create a longer (or thicker) predetermined structure 100. However, the predetermined structure may be a single substructure, which may also be within the scope of the present invention. As shown in FIGS. 1 and 2, the given structure has a hole or opening 102 of approximately 0.20 mm, but as will be described in more detail below, such that it will be 100-1500 nm in the final structure. It can be any suitable size. In fact, the openings are shown as circular, but this need not be the case and can be on the order of about 0.10 mm to about 0.5 mm in diameter. It is also preferred, but not necessary, to align the openings 102 in each substructure with the openings 102 in adjacent substructures before fusing to produce a longer predetermined structure 100. I want to be.

The predetermined structure 100 is then placed in a suitable oven and the binder is burned, leaving only the glass powder in the predetermined structure. Binding agent, in order to avoid the inclusion of structural deformation and gas, it is preferable to burn at a temperature below the glass transition temperature T _g. Next, the sintering step described later is preferably performed at a temperature _lower than the glass crystallization temperature T _{x in} order to prevent crystallization of the glass. Otherwise, the subsequent process steps of redrawing the structure may be hindered. The binder is burned out, and the sintering process can be performed up to the sintering temperature of the materials used, compared to other materials such as ceramics, metals, metal alloys, etc. The requirements are more restrictive. Furthermore, it is preferable to burn the binder under an inert atmosphere such as helium, argon, or nitrogen. When the combustion occurs in the presence of oxygen and the glass is, for example, silica-based glass, cristobalite may be formed in a predetermined structure, which may not be suitable for the intended use.

 In one preferred embodiment, the combustion schedule begins by heating a predetermined structure from room temperature (or ambient temperature) to 150 ° C. in 1 hour. Next, the predetermined structure is heated from 150 ° C. to 350 ° C. at a heating rate of about 10 ° C./hour and held at 350 ° C. for at least 1 hour to continue combustion. Finally, the predetermined structure is heated from 350 ° C. to 650 ° C. at a heating rate of about 10 ° C./hour and held at a temperature of 650 ° C. for at least 1 hour.

 This combustion schedule will eliminate about 90% of the binder from the given structure. Although a reduction in the combustion schedule is possible, preferably at least 75% of the binder should be removed from the given structure during the binder combustion process.

 The predetermined structure 100 is then sintered, preferably in the same oven and in a similar inert atmosphere, to harden the glass powder. If sintering is performed in a separate oven or place, care must be taken to avoid disturbing the structure while moving the structure prior to the sintering process. During the sintering stage, the predetermined structure 100 becomes a first glass structure that is essentially the same in arrangement and size as the predetermined structure.

 The first glass structure is then heated and drawn or stretched to a reduced diameter as is well known in the art to provide a second reduced cross-sectional size compared to the first glass structure. Manufacture glass structures. The first glass structure can be heated to an appropriate temperature to draw the first glass structure and depends on the composition of the glass structure. For example, if the glass is a silicate glass, it is likely that a temperature higher than 1000 ° C. or higher than 1100 ° C. may be used to draw the glass structure to a reduced diameter. However, lower draw temperatures could also be employed, particularly when the glass is a non-silicate glass composition. In one exemplary embodiment, the first glass structure is drawn to about 1000 times its original length. In drawing the first glass structure, the cross-section of the second glass structure is reduced to a size that is less than 1/10, less than 1/500, and less than 1/800 of the first glass structure. sell. Thus, for example, when drawing the first glass structure into the second glass structure, the 0.2 mm diameter opening in the first glass structure is about 200 nm or less in the second glass structure, The cross section of the second glass structure is about 0.5 mm × 0.5 mm. In order to maintain the symmetry of the first glass structure throughout the redraw process, it is preferable to use a differential pressure control system. In the differential pressure control system, the first glass structure continues to be pressurized and the differential pressure is controlled throughout the redraw process steps. Thus, for example, the holes 102 can be pressurized during the draw process so that they do not collapse during the diameter reduction phase.

 The stretched second glass structure can then be separated into lengths appropriate for the desired application. One typical application is a photonic or phononic bandgap structure made of glass with submicron and nanosized features. For example, these structures can be used as polarizers in the visible or infrared region of the light spectrum. For example, referring to FIG. 2, a structure having holes or openings 102 with a pitch of about 2 to 300 nm (distance between the centers of the holes) can be used as a photonic polarizer. This structure can be achieved by drawing the first glass structure, where the holes can have a pitch of about 100 micrometers to 1 mm. In one embodiment, the starting (first) glass structure holes have a pitch of about 100 micrometers, but a second glass structure with a diameter of 100 nm, comparable to a 1/1000 reduction in diameter. Is drawn to. This is because a glass structure having a repeating structure (eg, a hole) with a pitch of less than 500 micrometers inside, more preferably less than 250 micrometers inside is less than 1/3000, more preferably 2000 of the starting glass structure. It illustrates that it can be achieved by reducing the diameter to less than a part, and more preferably only a thousandth. Since the second glass structure is segmented, the misalignment of the opening 102 between the substructures becomes obvious and these segments can be easily discarded.

 It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (5)

A method of manufacturing a submicron or nano-sized glass band gap structure, comprising:
A glass mixture containing glass powder and binder is distributed into one layer at a time to produce a predetermined structure;
Removing at least 75% of the binder from the predetermined structure during the binder combustion step;
Sintering the predetermined structure to produce a first single glass structure having a predetermined cross-sectional area;
Drawing the first single glass structure into a second single glass structure;
Having each process,
The method, wherein the second single glass structure has a cross-sectional area that is at least 10 times smaller than a predetermined cross-sectional area of the first single glass structure.   The method of claim 1, wherein the structure is one of a photonic and phononic bandgap structure.   The method of claim 1, wherein the structure is a photonic polarizer.   The method of claim 1, wherein the first single glass structure has an opening with a diameter of about 100-500 micrometers.   The method of claim 1, wherein the second single glass structure has an opening having a diameter of about 50-1500 nanometers.

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