Patent Application
20220242036
Embodiments of the present invention relate to systems and methods for forming monolithic components for use in systems such as electron microscope systems.
Often in electron optics it is both time consuming and costly to machine complex electron optical elements (such as einzel lenses and deflectors). This leads to electron microscopes and dedicated matter optics experiments to be comparatively expensive. It is therefore desirable to create a fast and cost-effective production method for such components. It is also desirable for these components to be monolithic constructions to avoid the need for assembly.
According to an embodiment, a three-dimensional (3-D) printer is used for making electron microscope optics components, and other components for other electromagnetic-based systems. 3-D printing technologies advantageously enable printing with both conducting and insulating materials; conductive materials are used to create required electric potentials, and insulating materials are used to keep the elements electrically isolated.
According to an embodiment, a method of forming a monolithic electron optics component is provided. The method includes providing a dual-nozzle printing head having first and second printing nozzles, heating the dual-nozzle printing head to a desired temperature so that both the first nozzle and the second nozzle are heated to substantially the same, desired temperature, extruding a non-conductive filament material through the first nozzle, and withdrawing a conductive filament material through the second nozzle to form a device component. The desired temperature is typically above a melting temperature of the conductive filament material, above the melting temperature of the non-conducting filament material and lower than the temperature at which the printed device component or object sags under its own weight after printing and bleeding of the non-conducting filament material over the conducting filament material occurs.
According to another embodiment, a non-transitory, computer-readable medium is provided that has or stores instructions thereon which, upon execution by one or more processors, alone or in combination, provide for execution of the method of forming a monolithic electron optics component by controlling a 3-D printer having a dual-nozzle printing head including a first printing nozzle and a second printing nozzle.
Embodiments of the present invention will be described in greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and/or illustrated herein can be used alone or combined in different combinations in embodiments of the invention. The features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following:
According to certain embodiments, monolithic electron optics components, such as an electron deflector, an electrostatic quadrupole lens, a focusing lens, such as a three element cylindrical focusing lens, and other components may be formed using 3-D printing technologies as described herein. In certain aspects, printing is done using a dual-headed nozzle to enable switching between printing with a conducting filament material and printing with a non-conductive filament material, or printing simultaneously with both a conducting filament and a non-conductive filament.
An example of a useful dual-nozzle printing head is a LULZBOT TAZ 6 printer with a dual extruder tool-head (v2). An example of a useful conducting filament is Proto-Pasta PLA conductive CDP 12805, and an example of a useful non-conductive filament is Proto-Pasta Everyday PLA. Outgassing of these printing materials, e.g., when used for electron microscope system components or other electron optics system components, is advantageously sufficiently small so as to maintain the system's vacuum quality. One skilled in the art will recognize other useful conductive and non-conductive printing materials for use with a 3-D printer.
One of the principle limitations is the scale/size of the printed objects. This is due, in part, to the intrinsic structural fragility of the filament material(s) and printing resolution of the printer. Another limiting factor of these monolithic devices is the conductive material's tendency to bleed over the nonconductive material, which tends to defeat the electrical isolation of the device. This is due to the way the printing material is deposited and shaped. The solid Polylactic Acid (PLA) filament material is heated and melted while being pushed through an extruding nozzle in a liquid state, and then cools back into solid form on a platform (e.g., print bed 106). While conductive PLA has a different melting point than the nonconductive PLA, both printing nozzles in the dual-nozzle printing head are heated to the same temperature. One solution to this is to set the printer head to above the higher melting point of the two materials. However, if the printing temperature is too high then the conductive filament may begin to leak through its nozzle even if it is shut off. Additionally, if the filament is too hot then the material may begin to expand. Therefore, there is a narrow range of tolerated temperature for the printing to function correctly, and the printer is operated to withdraw the conductive filament while not being extruded. For example, for PLA, the operating temperature may be between about 205° C. and about 210° C. Various nozzle tip diameters also provide optimized resolution and help avoid the aforementioned problems. In certain embodiments, the nozzle diameter may be between about 1.0 mm and 1.5 mm. For example, a standard nozzle size of 1.5 mm resulted in bleeding. The use of a nozzle of 1.2 mm solved this problem for the particular materials used. It should be appreciated that other nozzle tip diameters may be used depending on the particular filament material used. Finally, cooling of the deposited material needs to be considered to avoid the situation that the printed objects after printing may deform under the pressure of their own weight. A fan may be used during the printing process to provide sufficient cooling.
According to certain embodiments, an electron deflector (which can steer the electron beam in both transverse dimensions) and an electrostatic quadrupole lens (with a hyperbola design) were made according to the methods herein. An example of a 3-D printed electron deflector component is shown in
To test these fabricated device components, the deflector and quadrupole lens were installed in a vacuum chamber and arranged into a simple electron optics setup as shown in
The complete testing rig was placed in a regular high vacuum chamber and pumped down with a turbo and roughing pump. With the printed elements installed, their outgassing was limited so that the vacuum system was able to pump down to a final pressure of 10′ Torr. This implies that the mean free path of the electrons is ˜6.9 m. Considering that the entire path length is only ˜0.60 m, this implies that the electron beam is unimpeded and the 3-D printed plastic electron optics elements do not outgas to a detrimental degree.
When observing the electron beam with the MCP, the imaged beam spot maintained its narrowness with time. This indicates that there is no appreciable charging taking place in the system. To demonstrate the functionality of the deflector element, the letter N was written on the fluorescent screen using a manually programmed master-slave pair of SRS function generators running at 10 kHz as shown in
To test the effectiveness of the quadrupole lens, voltages differences of about ±1 V were applied to the set of diagonal hyperbolic electrodes of the quadrupole lens, while the deflector plates were scanning. The result was that the “N” at the detector was stretched along the positively-biased diagonal, and compressed along the negatively biased diagonal as shown in
where the squeezing factor S is defined as the ratio between the magnification factor in the elongation direction Me over the magnification factor in the compression direction Mc and Δ=eV0l1l2L/(r02E(l1+l2)). This result can be obtained from applying the impulse approximation and assuming a uniform saddlepoint potential over the length of the quadrupole. The applied voltage difference V0 is about 1V, the quadrupole length L is 0.04 m, the electrode distance 2r0 is 20 mm, the electron energy E is 100 eV, the distance from the deflection plates to the quadrupole l1 is 0.3 m and from the quadrupole to the detector l2 is 0.3 m and the electron charge is given by e. The measured values for the image are Me=1.45 and Mc=1.70, giving S=2.5. The estimated theoretical value S=4. Given the crude approximation does indicate that the order of magnitude of the experimental design is correct.
Advantageously, functioning electron optical components can be, and have been, successfully produced with a commercial 3-D printer with a dual-nozzle printing head according to embodiments. Such methods provide a tangible step toward developing an affordable electron microscope or other electron optics systems that could become more cost effective and readily accessible to larger group, including for example high schools.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, the claimed embodiments include all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by embodiments unless otherwise indicated herein or otherwise clearly contradicted by context.
This Application is a continuation of U.S. patent application Ser. No. 16/290,194, filed Mar. 1, 2019, which claims priority to U.S. Provisional Patent Application No. 62/636,940, by Batelaan et al., entitled “SYSTEMS AND METHODS FOR FORMING MONOLITHIC ELECTRON MICROSCOPE COMPONENTS,” filed Mar. 1, 2018, both of which are incorporated in their entirety herein by reference.
This invention was made with government support under Grant Number 1602755 awarded by the National Science Foundation. The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 62636940 | Mar 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16290194 | Mar 2019 | US |
| Child | 17724656 | US |
