Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J63/00—Cathode-ray or electron-stream lamps
  • H01J63/06—Lamps with luminescent screen excited by the ray or stream
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent materials, e.g. electroluminescent or chemiluminescent
  • C09K11/08—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials
  • C09K11/64—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials containing aluminium
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J61/00—Gas-discharge or vapour-discharge lamps
  • H01J61/02—Details
  • H01J61/52—Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space
  • H01J61/523—Heating or cooling particular parts of the lamp
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J63/00—Cathode-ray or electron-stream lamps
  • H01J63/02—Details, e.g. electrode, gas filling, shape of vessel

Definitions

• UV fight is a form of electromagnetic radiation with wavelengths from about 10 nanometers (nm) to 400 nm. UV light has a shorter wavelength than visible light, but longer than X-rays. Short wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact For humans, suntan and sunburn are fiuniliar effects of exposure of the skin to UV light, along with increased risk of skin cancer.
• UVC spectrum of 190 nm to 280 nm, which can be used for disinfection because UVC light is strongly absorbed by nucleic adds which can damage DNA and RNA.
• proteins in the cell’s cytoplasm effectively shield mammalian nucleus DNA from ⁇ 230 nm UV light Therefore, a UVC lightsouroe with a wavelength from 190-230 nm is effective at sterilizing surfaces without posing a danger to humans in foe vicinity. Below 190 nm a UV light would produce significant amounts of ozone, which have been known to. have deleterious effects on humans.
• Low pressure mercury vapor lamps have been used to produce UVC fight for sterilization. Such lamps are energy efficient and cost effective but suffer from their use of mercury, which is an environmental hazard and can be toxic to humans. There has been a movement away from the use of low pressure mercury vapor lamps in recent years due to environmental aid health, concerns.
• Light Emitting Diodes have also been used to produce UVC light. While they do not include mercury or other heavy metals, they are not very efficient and are relative low capacity compared to other UVC light technologies.
• Pulsed Xenon lamps produce a wide spectrum of UV light but are relatively expensive compared to other technologies. Since the spectrum of UV is so wide, the output of the lamps need to be filtered to attenuate wavelengths outside of the 190-230 nm range.
• a cathode-ray tube ultraviolet light source includes a metal housing provided with a light-transmissive window, a heatsink disposed within the metal housing, a phosphor having a first surface and an opposing second surface, wherein the second surface of the phosphor is in thermal contact with the heatsink, and an electron gun capable of developing an electron beam to impinge upon the first surface of the phosphor, whereby light emitted from the second surface of the phosphor is directed through the light-transmissive window.
• a reflector is disposed within the metal housing to direct the light emitted fiom the first surface towards the light-transmissive window.
• a method for operating a cathode-ray tube ultraviolet light source includes directing an electron beam to a first surface of a phosphor that has a second surface in thermal contact with a heatsink; and reflecting light emitted from the second surface of the phosphor through a light-transmissive window.
• the electron beam focus and/or a scanning of the electron beam on the first surface of the phosphor are used to vary the angular emission characteristics of the light emitted by the light source.
• multiple phosphors are used to also vary the spectral characteristics of the emitted light.
• UVC light can be produced in an efficient, cost-effective manner without the use of dangerous and environmentally unfriendly heavy metals such as mercury.
• Figure 1 is a first example embodiment of a cathode-ray tube ultraviolet light source
• Figure 1 A is a perspective view of an example heatsink with a radiation shield
• Figure 2 is a second example embodiment of a cathode-ray tube ultraviolet light source
• Figure 3 is a third example embodiment of a cathode-ray tube ultraviolet light source
• Figure 4 is a fourth example embodiment of a cathode-ray tube ultraviolet light source
• Figure 5 is a fifth example embodiment of a cathode-ray tube ultraviolet light source
• Figure 6 illustrates a first spectral tuning method for a cathode-ray tube ultraviolet light source using a plurality of phosphors.
• Figure 1 is a first example embodiment of a cathode-ray tube ultraviolet light source 10 and includes a metal housing 12 provide with a light-transmissive (e.g. transparent) window 14, a heatsink 16, a phosphor 18 having a first surface 20 and an opposing second surface 22 in thermal contact with the heatsink 16, and an electron source or “gun” 24 capable of developing an electron beam 26 to impinge upon the first surface 20 of the phosphor 18.
• Light 28 emitted from the first surface 20 of the phosphor is directed through the light-transmissive window 14 as emitted light 29 by a reflector 30 including a first surface 32, a second surface 34 and an aperture 36 through which the electron beam 26 can pass.
• the light source is under vacuum so as not to impede the electron beam 26 and to prolong the life of the components of the light source.
• reflector 30 is parabolic with a reflective aluminum film provided on the first stirface 32.
• a getter material 38 is applied as a film to the second surface 34 of the reflector 30 and inside portions of the metal housing 12.
• the metal housing 12 takes the place of the typical glass envelope of a cathode- ray tube (CRT). It is advantageous in that it provides shielding of, for example, X-rays generated by the impact the electron beam 26 on the phosphor 18 and because it can be considerably thinner and more durable than a glass envelope. It is therefore safer in that it reduces the chance of implosion of the envelope.
• the metal housing 12 is preferably at least partially coated with a non-conductive material to reduce the chance of ground faults and to provide a non-conductive surface for the attachment of additional circuitry and devices.
• the metal housing 12 can include porcelain coated steel or a polymer coated steel. Other metals and metal alloys are also suitable for use in the metal housing.
• the light-transmissive window 14 can be conveniently made from vitreous quartz, which is readily available and reasonable in price. Other materials that are suitable include magnesium fluoride glass and calcium fluoride glass. For high-end applications, flat sapphire is also suitable. Preferably the light-transmissive window is highly transparent to 190 -230 nm wavelengths.
• the heatsink 16 in this example embodiment, fanned as a flange or frame to connect the light transmissive window 14 to the rest of the metal housing 12. As such, a portion of the heatsink 16 extends outside of the metal envelope 12 and a portion, in the form of a web of material, extends across the inside of the metal housing 12 to provide a support for the phosphor 18. Heat generated by the impingement of the electron beam 26 on the phosphor 18 therefore is transferred to the heat sink 16 and thermally conducted outside of the metal housing 12 to be dissipated by convection and radiation into the ambient environment.
• the metal housing 12 also serves as a heatsink to remove excess heat from the light source 10.
• FIG. 1 A an example heatsink 16’ and a supplemental radiation shield 15’ is shown.
• the ecample heatsink 16’ is wheel-shaped and includes a central hub 17’, three radial spokes 19’ and a circular rim 21’ provided with a number of heat fins 23’.
• the heatsink 16’ is designed to be sandwiched between, for example, the metal housing 12 and the light-transmissive window 14 of Fig, 1, forming a high-pressure seal with suitable gaskets (not shown).
• the radiation shield 15’ fits into a recess 25’ of the hub 17’ and is preferably held in place with a thermally conductive adhesive and/or mechanically.
• the radiation shield 15’ is preferably made from a dense metal such as molybdenum to increase radiation shielding for high-energy emissions of the phosphor such as x-rays.
• a getter material 38 is preferably provided within the UV light source 10, e.g. on portions of the reflector 30 and at least some of the inside surfaces of the metal housing 12.
• the getter can be, for example, barium or a barium alloy, and is provided to remove gaseous contaminants from within the metal housing.
• the getter is applied after the light source 10 is under vacuum, such as by the evaporative heating of a disc or ring of barium 40 by a resistive heater 42.
• the wires 44 for the resistive heater 42 can extend through an end-plug 46, made for example from glass, as pins. Other pins through the end-plug 46 can be used to power and control the electron source 24 and/or other internal components of the UV light source 10.
• FIG. 2 is a second example embodiment of a cathode-ray tube ultraviolet light source 10’ which is similar to the first example light source 10, where like reference numerals refer to like components or elements.
• a heatsink 16’ includes a primary reflector portion 48 which focusses the emitted light 28 on a secondary reflector 30’ before passing through the window 14 as emitted light 29. This allows the secondary reflector 30’ to be of a smaller diameter than reflector 30.
• FIG 3 is a third example embodiment of a cathode-ray tube ultraviolet light source 10” which has an off-axis emission of UV light 29, where like reference numerals to those used with respect to Figs. 1 and 2 refer to like components or elements.
• the electron beam 26 of electron gun 24 passes through an aperture 36’ ’ of a reflective optic 30” to impinge upon a phosphor 18 of a heatsink 16’ ’ which forms a part of a substantially metal housing 12”.
• the heatsink 16” has a section 50 which serves as a reflective optic to direct the UV light 28 emitted by the phosphor towards the reflective optic 30’ ’ and, from there out of window 14”.
• the window 14 may serve as a refractive optic to help collimate or otherwise shape the emitted light 29, which is at approximately right angles to the electron beam 26 in this example.
• FIG 4 is a fourth example embodiment of a cathode-ray tube ultraviolet light source 10’” with the notable change of an electron gun 24’ ’ ’ and a curved path for the electron beam 26’”, where like reference numerals refer to like components in the previously described embodiments.
• This fourth example embodiment provides a compact electron source with a bent beam path to reduce the overall size of the metal housing 12” ’ .
• a series of focusing and deflecting apparatus bends the electron beam 26”’ so that it passes through an aperture 36” ’ of reflector 30” ’ at an angle to impinge upon the phosphor 18.
• the UV light emitted by the phosphor 18 is reflected by reflector 30” ’ through a transparent window 14”’ supported by a heat sink 16’” as emitted light 29.
• Figure 5 is a fifth example embodiment of a cathode-ray tube ultraviolet light source 10”” having a metal housing 12”” with a heatsink section 16””.
• the electron gun 24 produces an electron beam 26 which impinges on phosphor 18”” at an angle such that light 28”” is emittedthrough awindow l4””.
• this is the first embodiment that does not use a reflector to redirect or collimate the light 28”” emitted by the phosphor 18””.
• this example embodiment is simple in design and can be less expensive to produce that certain ones of the other example embodiments.
• the emission wavelength of a light source 10 is determined by the phosphor material being irradiated.
• AIN is a material that can emit UVC light at 210 nm.
• AlGaN can emit at different (longer) wavelengths.
• the amount of gallium will determine the emission wavelength which will increase with the amount of gallium added to the alloy.
• dopants can be added to AIN or AlGaN to change their emission wavelengths.
• hexagonal boron nitride will emit UVC light in the range of 210-220 nm.
• Preferred electron beam energy is 6,000 to 34,000 V.
• Beam current can range from 1 ⁇ A to 5 mA.
• a spot size in the range of 0.1 to 1.0 mm diameter is suitable.
• a spot size of up to 5 mm diameter may be suitable.
• a phosphor material that emits in the wavelength range of about 450 nm to about 650 nm may be incorporated with a phosphor material that emits in the wavelength range of about 190 nm to about 280 nm in order to provide a visual indication that the device is operating.
• Figure 6 illustrates a first spectral tuning method for a cathode-ray tube ultraviolet light source using a plurality of phosphors.
• four different phosphors are laid out in a 2x2 grid 70 and comprise a Material A, Material B, Material C and Material D.
• a “spirograph” type electron beam (“e-beam”) pattern 72A over Material A produces an emission spectra 74A.
• a spirograph type e-beam pattan 72B ova Material C and Material D produces a different emission spectra 74B.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Discharge Lamps And Accessories Thereof (AREA)
• Radiation-Therapy Devices (AREA)

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Citations (10)

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• 2022
  • 2022-08-31 MX MX2024002605A patent/MX2024002605A/es unknown
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  • 2022-08-31 WO PCT/US2022/042180 patent/WO2023034399A1/en not_active Ceased
  • 2022-08-31 KR KR1020247010693A patent/KR102971255B1/ko active Active
  • 2022-08-31 AU AU2022339597A patent/AU2022339597A1/en active Pending
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• 2025
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