NANO-GAS LIGHT SOURCES BASED ON GRAPHENE FOR DISPLAYS
20190221420 ยท 2019-07-18
Inventors
Cpc classification
H01J61/16
ELECTRICITY
H01J9/18
ELECTRICITY
H01J61/14
ELECTRICITY
H01J61/32
ELECTRICITY
H01J61/78
ELECTRICITY
G09G2320/064
PHYSICS
H01J9/323
ELECTRICITY
International classification
Abstract
A gas light source is disclosed where gas is contained within a graphene cylinder or graphene capsule. Electrodes extending into the graphene cylinder or capsule are stimulated by an electric voltage to emit light. Eight graphene cylinder light sources can be arranged into a seven-segment alpha-numeric display having a decimal point. Different gases produce different colors of light. Three gas light sources having different gases can be arranged into an RGB pixel. An array of RGB pixels can be formed into a display.
Claims
1. A Red-Green-Blue (RGB) light emitting pixel element, comprising: a graphene cylinder filled with a red-light emitting gas, the graphene cylinder having an electrode secured at each end, wherein red-light is emitted through the graphene cylinder by the red-light emitting gas when it is excited by a voltage placed across the electrodes; a graphene cylinder filled with a green-light emitting gas, the graphene cylinder having an electrode secured at each end, wherein green-light is emitted through the graphene cylinder by the green-light emitting gas when it is excited by a voltage placed across the electrodes; and a graphene cylinder filled with a blue-light emitting gas, the graphene cylinder having an electrode secured at each end, wherein blue-light is emitted through the graphene cylinder by the blue-light emitting gas when it is excited by a voltage placed across the electrodes.
2. The Red-Green-Blue (RGB) light emitting pixel element of claim 1, wherein the red-light emitting gas includes neon, wherein the green-light emitting gas includes krypton, wherein the blue-light emitting gas includes mercury vapor or xenon.
3. The Red-Green-Blue (RGB) light emitting pixel element of claim 2, wherein the graphene cylinders are carbon nanotubes.
4. The Red-Green-Blue (RGB) light emitting pixel element of claim 3, further comprising a processor controller coupled to the RGB light emitting pixel element to Pulse-Width Modulate (PWM) it to produce different desired colors and time dependent light color patterns at various brightness levels.
5. The Red-Green-Blue (RGB) light emitting pixel element of claim 4, wherein each graphene cylinder is sealed to contain the light emitting gasses within them by their respective electrodes.
6. The Red-Green-Blue (RGB) light emitting pixel element of claim 4, wherein each graphene cylinder is sealed to contain the light emitting gasses within them by their respective electrodes and a sealing material bonding each graphene cylinder to their respective electrodes selected from the group consisting of epoxy, cyanoacrylate, glass, graphene, and a composite material.
7. The Red-Green-Blue (RGB) light emitting pixel element of claim 4, wherein the red-light, green-light, and blue-light emitting gasses are maintained within their respective graphene cylinders at a pressure range selected from the group consisting of 2-5 Torr, 5-10 Torr, 10-15 Torr, and 15-20 Torr.
8. A display formed of gas-filled light emitting RGB pixels, comprising: an array of gas-filled RGB pixels formed of gases sealed within graphene cylinders each having pairs of electrodes; and a processor controller device that activates each gas-filled RGB pixel to create images on the display, wherein the processor controller is connected to the array of gas-filled RGB pixels through display electrodes and address electrodes, wherein the processor controller can activate individual RGB pixels through a combination of the display and address electrodes.
9. The display formed of gas-filled light emitting RGB pixels of claim 8, further comprising a bottom glass substrate and a top glass substrate between which the arrays of gas-filled RGB pixels are positioned.
10. The display formed of gas-filled light emitting RGB pixels of claim 9, further comprising a planarization dielectric layer to electrically insulate the display electrodes and address electrodes and provide flat surfaces for the bottom and top glass substrates.
11. The display formed of gas-filled light emitting RGB pixels of claim 10, wherein the processor controller device Pulse-Width Modulates (PWM) the array of gas-filled RGB pixels to cause the display to produce different colors at different brightness levels to show images.
12. The display formed of gas-filled light emitting RGB pixels of claim 11, wherein the gases within the graphene cylinders are maintained within their respective graphene cylinders at a pressure range selected from the group consisting of 2-5 Torr, 5-10 Torr, 10-15 Torr, and 15-20 Torr.
13. The display formed of gas-filled light emitting RGB pixels of claim 12, wherein each gas-filled RGB pixel includes a red-light emitting gas that includes neon, a green-light emitting gas that includes krypton, and a blue-light emitting gas that includes mercury vapor or xenon.
14. The display formed of gas-filled light emitting RGB pixels of claim 13, wherein each graphene cylinder is sealed to contain the gasses within them by their respective electrodes.
15. The display formed of gas-filled light emitting RGB pixels of claim 13, wherein each graphene cylinder is sealed to contain the gasses within them by their respective electrodes and a sealing material bonding each graphene cylinder to their respective electrodes selected from the group consisting of epoxy, cyanoacrylate, glass, graphene, and a composite material.
16. A graphene-capsule gas lamp, comprising: a graphene capsule filled with a gas; a pair of electrodes extending through a bottom portion of the graphene capsule into the gas; and a plug that seals the bottom of the graphene capsule where the electrodes extend therethrough.
17. The graphene-capsule gas lamp of claim 16, wherein the gas is selected from the group consisting of neon, argon, helium, xenon, krypton, hydrogen, mercury vapor, and carbon dioxide.
18. The graphene-capsule gas lamp of claim 17, wherein the gas is maintained at a pressure range selected from the group consisting of 2-5 Torr, 5-10 Torr, 10-15 Torr, and 15-20 Torr.
19. The graphene-capsule gas lamp of claim 18, wherein the gas is excited to emit light that travels through the graphene capsule when a voltage is applied across the electrodes.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself; however, both as to its structure and operation together with the additional objects and advantages thereof are best understood through the following description of the preferred embodiment of the present invention when read in conjunction with the accompanying drawings, wherein:
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DETAILED DESCRIPTION
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[0024] Graphene is a hexagonal lattice of carbon atoms that form an atomically contiguous sheet. Graphene is formed of an atomically contiguous lattice of covalently-bonded carbon atoms. Graphene sheet, also referred to as a graphene lattice, is a flat monolayer of carbon atoms that are tightly packed into a two-dimensional lattice. Graphene is 97.7% optically transparent. Graphene is an extremely strong material due to the covalent carbon-carbon bonds. It is desirable to utilize graphene lattices that are defect free as the presence of defects reduces the strength of the graphene lattice. The intrinsic strength of a defect free sheet of graphene 100 is 42 N/m, making it one of the strongest materials known. The strength of graphene is comparable to the hardness of diamonds. Graphene is also a highly flexible material. Multiple monolayers of graphene sheet can be grown on top of each other to create a multi-layer graphene sheet. Graphene exhibits a wavelength dependent index of refraction.
[0025] Graphene is also an impermeable membrane to even the smallest atoms, thereby maintaining the atmosphere of a vacuum or gas within the graphene cladding 18. Although it is only one atom thick, an interesting property of graphene is its impermeability. Graphene's p-orbitals forms a dense, delocalized cloud that blocks the gap within its aromatic rings. This creates a repelling field, which does not allow even the smallest molecules, like hydrogen and helium, to pass through even when 1-5 atm pressure difference is imposed across its atomic thickness at room temperature. The ability to withstand such pressure differences (6 atm) in graphene is a result of its high strength (breaking strength=42 N/m) and Young's modulus (1 TPa), which retains the structural integrity of graphene. Thus, a graphene cylinder can maintain a core made of a vacuum or gas when each end of the graphene cylinder 18 is sealed. A further discussion on graphene's impermeability is provided in the following scientific article hereby incorporated by reference: Vikas, Berry. Impermeability of graphene and its applications. Carbon (2013), http://dx.doi.org/10.1016/j.carbon.2013.05.052.
[0026] Graphene cylinder 20 contains a gas 22. Gas 22 may be neon, argon, helium, xenon, krypton, hydrogen or carbon dixoide. Electrodes 18 are bonded to each end of graphene cylinder 20 to form a gaseous seal with graphene cylinder 20, thereby holding gas 22 within gas light tube assembly 12 regardless of the atmosphere external to gas light tube assembly 12 due to the gaseous impermeability of graphene cylinder 20, electrodes 18, and the gaseous seal formed between graphene cylinder 20 and electrodes 18. Gas 22 is contained within gas light tube assembly under a particular pressure range. This pressure range may be 2-5 Torr, 5-10 Torr, 10-15 Torr, or 15-20 Torr.
[0027] Carbon nanotubes can be conducting or semiconducting. The diameter of a carbon nanotube and the amount of twist in its lattice determines whether it's metallic or semiconducting. Electrons in carbon nanotubes can only be at certain energy levels, just like electrons in atoms. A nanotube is metallic if the energy level that allows delocalized electrons to flow between atoms throughout the nanotube (referred to as the conduction band) is right above the energy level used by electrons attached to atoms (the valance band). In a metallic nanotube, electrons can easily move to the conduction band. A nanotube is semiconducting if the energy level of the conduction band is high enough so that there is an energy gap between it and the valance band. In this case, additional energy, such as light, is needed for an electron to jump that gap to move to the conduction band. While there is no gap between the valance and conduction bands for armchair nanotubes (which makes them metallic), an energy gap does exist between the valance and conduction bands in about two thirds of zigzag and chiral nanotubeswhich makes them semiconducting. Conducting carbon nanotubes act as one-dimensional nanowires. Semiconducting carbon nanotubes are basically non-conducting, have small dielectric constants, medium to large band gaps and hence can act as insulating shields to electric fields generated by electrodes 18. It is desirable to make graphene cylinder 20 out of a semiconducting carbon nanotube. With semiconducting carbon nanotubes, electrodes 18 generate an electric field that causes gas 22 to discharge photons that are emitted through graphene cylinder 20 outward to the external environment creating a light source.
[0028] Graphene cylinder 20 may have end surfaces 24 that form a gaseous seal with electrodes 18 bonding electrodes 18 to graphene cylinder 20. These end surfaces 24 may be made out of a variety of materials that function to bond electrodes 18 to cylinder 20 and form a gaseous seal to keep gas 22 contained entirely within assembly 12. End surfaces 24 may be made of an adhesive. Such an adhesive could include, but is not limited to, an epoxy and cyanoacrylate. Other materials for end surfaces can include a glass, graphene, or composite material.
[0029] Controller power source 16 controls the operation of light source 10. For example, controller 16 may turn light source 10 ON and OFF. In addition, controller 16 may operate light source 10 with a Pulse Width Modulated (PWM) voltage in order to create the desired light with a reduced amount of power usage. It is possible to vary the brightness of light source 10 with PWM. Controller 16 may further control light source 10 to operate to produce various time dependent patterns of light, such as a blinking light that varies in the speed and duration at which it blinks. Electrodes 18 may be made of a metal. Electrodes 18 may take the form of a metal nanowire. Alternatively, electrodes 18 may be formed of conducting carbon nanotubes. A starting voltage (usually 55-110 volts AC, or 90-140 volts DC) is applied, the gas ionizes and starts to glow permitting a very small current to travel from one electrode to the other. Once ionized, a lower voltage will maintain the operation of the light source 10. The maintaining voltage is usually 10-20 volts below the starting voltage, depending on the light source 12 and the operating current. For light source 10 operating on AC voltages of 60 Hz or higher frequency, the light output will appear to the eye as continuous.
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[0036] A light assembly is disclosed that is formed of a carbon nanotube 20 having an electrode 18 inserted in each end. The electrodes 18 form a gaseous seal with the carbon nanotube 20 at each end of the carbon nanotube 20. A gas 22 is sealed within the carbon nanotube 20 by the electrodes 18. The gas 22 emits light through the carbon nanotube 20 when voltage is applied across said electrodes 18. The gas 22 may be neon, argon, helium, xenon, krypton, hydrogen and carbon dioxide. The light assembly 12 may also include a ring of sealant 34 bonding the ends of the carbon nanotube 20 to the electrodes 19 to form the gas seal. The ring of sealant 34 is applied over exterior surfaces of the electrodes 18 and the carbon nanotube 20. The ring of sealant 34 may be formed of an adhesive such as an epoxy or cyanoacrylate (aka Super Glue). The ring of sealant 34 may also be formed of a glass. Alternatively, the light assembly 12 may include a pair of end surfaces 24 bonding each electrode 18 to each end of the carbon nanotube 20, thereby sealing the gas 22 within the carbon nanotube 20. These end surfaces 24 may be formed of graphene, an adhesive, or a glass. The light assembly 12 may also include a scaffolding to support the carbon nanotube 20 and hold it in a desired shape. This scaffolding may include a frame 26 having a patterned array of posts 28 where the carbon nanotube 20 is shaped and attached to the patterned array of posts 28 to form a desired light-emitting shape. Alternatively, the carbon nanotube 20 may be supported and placed into a desired shape by bonding it to a substrate 32 with bonding pads 30. The substrate 32 may be made of a glass, semiconductor, plastic, paper, graphene, carbon fiber composite, carbon fiber, or other composite material. The light assembly may also include a controller 16 configured to regulate the electrical operation of the light assembly. The controller 16 is electrically connected to the electrodes 18. It is desirable that the carbon nanotube 20 be made of a semiconducting carbon nanotube.
[0037] A gas light source 10 is disclosed that is formed of a graphene cylinder 20 having an electrode 18 inserted in each end where the electrodes 18 form a gaseous seal with the graphene cylinder 20 at each end of the graphene cylinder 20. A gas 22 is sealed within the graphene cylinder 20 by the electrodes 18. The gas 22 emits light through the graphene cylinder 20 when voltage is applied across the electrodes 18. The gas 22 may be neon, argon, helium, xenon, krypton, hydrogen or carbon dioxide. The gas light source 12 may also include a ring of sealant 34 bonding the ends of the graphene cylinder 20 to the electrodes 18. The ring of sealant 34 may be applied over exterior surfaces of the electrodes 18 and the graphene cylinder 20. The ring of sealant 34 may be formed of an adhesive such as an epoxy or cyanoacrylate. The ring of sealant 34 may also be formed of a glass. Alternatively, the light source may include a pair of end surfaces 24 bonding each electrode 18 to each end of the graphene cylinder 20, thereby sealing the gas 22 within the graphene cylinder 20. These end surfaces 24 may be formed of graphene, an adhesive, or a glass. The light source 12 may further include a scaffolding to support the light source 12 and hold it into a desired shape. This scaffolding may include a substrate 32 formed of glass, semiconductor, plastic, paper, graphene, carbon fiber, or composite material and bonding pads 30 attaching the graphene cylinder 20 to the substrate 32 and holding it into a visually desired shape. It is desirable that the graphene cylinder 20 be made of a semiconducting carbon nanotube.
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[0042] While the invention has been shown and described with reference to a particular embodiment thereof, it will be understood to those skilled in the art, that various changes in form and details may be made therein without departing from the spirit and scope of the invention.