KR100397720B1 - Fluorescent lamp - Google Patents

Abstract

Fiber cold cathode field emitters having a cold cathode fiber diameter of less than about 100 microns; An anode for sucking electrons emitted by the fiber cold cathode electric field emitter; A phosphor capable of contacting electrons emitted from a cold cathode field emitter that generates permanent light; And a vacuum enclosure of less than about 10 ^-5 Torr containing a cold cathode field emitter, an anode, and a phosphor in the enclosure.

Description

Fluorescent Lamps {FLUORESCENT LAMP}

TECHNICAL FIELD The present invention relates to lighting, and in particular, to lighting articles that use an appropriate phosphor in combination with a cathode field emitter. The present invention is the result obtained by contacting the energy part (Contract No. W-7405-ENG-36).

Fluorescent lighting has been the standard lighting method for commercial buildings for many years. It is used at home level, but is generally applied where it is necessary to economically illuminate a large area. While incandescent tungsten lighting is less efficient and more expensive than fluorescent lighting, incandescent bulbs are becoming the basic lighting method for home lighting because of their convenience and economics.

Although fluorescent lighting is a very efficient method of illumination, it has some drawbacks. Some of these deficiencies are ecological. Fluorescent light tubes now contain very toxic regulated substances of mercury, so U.S. Classified as hazardous by the Environmental Protection Agency (EPA). This problem addresses U.S. Pat. Patent Nos. It causes a phenomenon in 5,229,686 and 5,229,687 and the like. In addition, but not all, ballast resistors required for most fluorescent lighting systems may contain polychlorinated biphenyl oils (PCB's), which are materials whose carcinogenicity is highly regulated by EPA.

In general, the generation of light in a fluorescent bulb takes several steps. First, liquid mercury in the tube is heated electronically to volatilize at least some of the mercury. An electric current then passes through the mercury vapor to excite the mercury in the plasma state. The excited mercury plasma emits ultraviolet (UV) light. Finally, the UV light strikes the phosphor in the bulb where the phosphor converts the UV light energy into emitted visible light. This light generation path has some performance deficiency. Compared with the conventional incandescent tungsten lighting system, the fluorescent lighting system is slow to start because mercury must first be heated to provide mercury vapor. Fluorescent light is also known to form acoustic noise due to the transformer and ballast resistor electronics required to activate and maintain the current flowing in the mercury vapor. Vibration of light output from fluorescent lights can be confusing to a person because it can occur when the system is cooled and initially turned on. Moreover, fluorescent lighting systems are incompatible with conventional dimming techniques, which use more exotic electronics to adjust the brightness output of light that requires expensive and dimmable fluorescent lighting. do.

I. Brodie, U.S. 4,818,914 discloses a lamp comprising an anode formed from an array of needle-like members emerging from one surface, an accelerator electrode formed from an array of penetrating openings, a layer of phosphor, and an anode electrode. The voltage applied across the cathode and accelerator electrodes, and across the cathode and anode, results in field emission from the cathode and electron collection by the anode. The impact of electrons on the phosphor layer results in light emission. Dworsky et al., U.S. 5,180,951 discloses a uniform light source composed of a substantially planar (flat) polycrystalline diamond film electron emitter. Y. Taniguichi et al., WO 94/28571 discloses a fluorescent tube light source comprising an amorphous diamond film deposited on a conductive filament and a film layer that emits light upon impact by emitted electrons. The amorphous diamond film is said to be composed of a plurality of dispersedly arranged electron emission positions, and each sub site has a plurality of sub regions in which electrons between sub regions are different.

It is an object of the present invention to provide mercury free fluorescent illumination using fiber field emission elements.

Another object of the present invention is to provide a fluorescent light which is generally turned on instantaneously.

Another object of the present invention is to provide a low voltage, low power backlight (back light).

Summary of the Invention

In order to achieve the above and other objects of the present invention, as embodied and broadly described herein, the present invention relates to a fiber cold cathode electric field emitter, a fiber cold cathode electric field emitter having a diameter of the cold cathode fiber smaller than about 100 microns. Containing a reactive anode of the electrons emitted by it, a phosphor capable of contacting electrons emitted from a cold cathode field emitter that generates permanent light, a cold cathode field emitter in a sealed enclosure, and an anode and a phosphor A lighting device including a vacuum hermetically sealed container of less than about 10 ^-5 Torr is provided. The permanent light preferably has a luminous intensity of at least 20 lumens per watt.

1 shows an elongated tube device according to the lighting device of the invention.

2 is an exploded view of a flat panel device according to the lighting apparatus of the present invention.

3 shows a light bulb device according to the lighting device of the invention.

4 is an illustration of a light beam generating device according to the lighting apparatus of the present invention.

5 shows a test device according to the lighting device of the invention.

6 is a diagram of a driver circuit for the lighting device of the present invention.

7 is an illustration of a light bulb device used in a standard light bulb socket.

FIELD OF THE INVENTION The present invention relates to field emission illumination devices and fiber field emission illumination (FFEL) devices.

The lighting device of the present invention utilizes field emission to generate light output from a phosphor, for example a cathode luminescent material.

The field emission illuminator comprises a fiber cold cathode field emitter. The field emission electron emitting material can be any material that can be provided in the form of a fiber. The field emission electron-emitting material of the fiber cathode is preferably diamond, diamond-like carbon or glassy carbon. Diamond is particularly good. The fibrous cathode is formed of one or more diamonds, diamond-like carbon or glassy carbon composite fibers consisting essentially of diamond, and diamond-like or glassy carbon on non-diamond core fibers. Non-diamond cores may be composed of conductive or semiconductor materials. Alternatively, the core may be composed of a non-conductive material surrounded by a film coating of conductive or semiconductor material. The core material in the diamond fiber may be, for example, conductive carbon such as graphite or a metal such as tungsten, or may be, for example, silicon, copper, molybdenum, titanium or silicon carbide. In other embodiments, the core may be composed of a more complex structure, for example a nonconductive material surrounded by a thin coating of conductive or semiconducting material. A diamond, diamond or glassy carbon layer is coated on the sheath. For example, the non-conductive core may be nylon or Kevlar (KEVLAR- ) (Kevlar May be a synthetic fiber such as EIdu Pont de Nemours and Company, Wilmington, DE) or an inorganic material such as polyester, ceramic or glass. In other embodiments, diamond, diamond-like carbon or glassy carbon precursors may be coated on a non-diamond core, or the core may be diamond, diamond-like carbon or free-carbon precursors, and the appropriate treatment of the precursors This forms diamonds, diamond-like carbons or glassy carbons.

In particular, the field emission illuminator is U.S. Patent Application No. 08 / 196,343 filed "Fiamond-Graphite Field Emitters" filed February 14, 1994, or "Diamond" filed February 14, 1994, Valone et al. Part of U.S. Patent Application 08 / 196,340, filed under the name "Fiber Field Emitters", described in U.S. Patent Application 08 / 387,539, filed February 13, 1995, entitled "Diamond Fiber Field Emitters." Fibrous cold cathode field emitters, which may be of the type, which are incorporated herein by reference. Cold cathode field emitters are also described in US Patent Preliminary Application 60 / filed under the name "Method for Creation of Controlled Field Emission Sites" dated August 14, 1995 by Freidmann or appropriate graphite fibers treated by exposure to strong ion beam treatment. Suitable graphite fibers treated by exposure to a laser as described in 002,277, or diamond coated or diamond-coated nickel coated KEVLAR as described in US Patent Application 08 / 387,539, filed February 13, 1995. Fibers, or any other suitable emitting fiber material, such as glassy carbon, fibers containing amorphous material exhibiting Raman peaks at about 1380 cm ⁻¹ and 1598 cm ⁻¹ . Here, "diamond type carbon" is used to designate the materials mentioned in the above data, such as diamond type carbon as well as carbon with microscopic content of free carbon and glass type carbon, all of which have the same performance as field emission materials. It is diamond-shaped.

In addition, the fibrous cold cathode may generally be a conductive material having an activated surface, ie it is generally suitable dimensions, ie smaller than about 100 microns, preferably smaller than about 15 microns, more preferably Can drain electrons at a relatively low bias voltage of less than about 10 microns. Among the titrants may include, for example, thin fibers, such as magnesium oxide, as appropriate on the activated surface based on the treatment of the fibers by flash heating.

Generally, the diameter of each of the fibers of the fiber cathode is less than about 100 microns, preferably less than about 15 microns, and more preferably less than about 10 microns. Smaller diameter fibers reduce the voltage needed to produce field emission. Preferably, the diameter is greater than 1 micron. In general, the diameter of the cold cathode fibers is substantially smaller than the dimensions of the metal filaments commonly used in currently available lighting devices. Since a single fiber can be used as the fiber cathode, it is generally desirable to use more than a single fiber, such as a fiber cathode, to provide redundancy of electron emission.

The phosphor used in the lighting device of the present invention is generally in any form suitable for generating visible light as it is impacted by electron emission. For example, the phosphor may be zinc oxide: zinc, zinc sulfide, cadmium sulfide, zinc cadmium sulfide, zinc selenide, zinc cadmium selenide yttrium silicate: cesium, zinc phosphate: magnese, or light according to appropriate excitation. It may be another known material that emits. Mixtures or compounds of phosphors may be used.

Phosphors used in the present invention can produce permanent light, that is, light from a particular point of the phosphor does not disappear easily over time as it is excited. In addition, the output from the excited phosphor can generate permanent visible light at a brightness of at least 20 lumens per watt.

The lighting device of the present invention comprises a fiber cold cathode field emitter, a phosphor, and an anode for sucking electrons emitted from the cold cathode field emitter, all of which are generally contained in an evacuated hermetically sealed container. Unlike standard mercury vapor fluorescent lighting, the lighting device of the present invention can be turned on instantaneously without the need for heating of mercury. No preservation of the plasma is required, and the light generated by the illumination device of the present invention can be readily dim or brighten immediately by adjusting the voltage applied to the fiber. When more voltage is applied, more electrons are emitted and collide by the phosphor material, which produces additional light output, ie brighter light. When less voltage is applied but above the minimum turn-on voltage for the fiber field emitter, less electrons are emitted and impinge on the phosphor material resulting in a decrease in light output, i.

Vacuum sealed containers typically maintain low pressure, such as at least about 10 ^-5 Torr. Such a vacuum sealed container may be, for example, a glass bulb or several sheets of glass paper interposed with a suitable spacer material.

The lighting device of the present invention utilizes electron emission induced by a directed and formable applied electric field. This is in contrast to illumination using plasma, which results in a non-directional light source. This makes it possible to achieve the construction of the present lighting device in a practical but colorful manner without limitations on traditional extension tubes. Whatever the shape of the lighting device, electron emission from the fiber cathode fiber is generated along the length of the fiber utilized and not at the end of the fiber.

In one embodiment of the invention shown in FIG. 1, the illumination 10 comprises a glass tube 12 as a vacuumable sealed container. The inside or the inner surface of the glass tube 12 may be coated with a transparent conductor such as an anode and a phosphor or a cathode light emitting material 13. The fiber cathode element 14, the fiber field emitter, is located in the glass tube 12. The end cap 16 includes a fiber cathode element 14 and electrodes connected to a transparent conductor coating or anode. The fibrous cathode device may consist of a single fiber and may comprise a plurality of fibers or may comprise a single thicker fiber. In general, a single fiber or each fiber constituting a plurality of fibers has a diameter of about 1 micron to about 20 microns, preferably about 5 microns to about 10 microns. The glass tube may be a circular cylinder as shown or may have a configured surface.

In another embodiment of the present invention shown in FIG. 2, the illumination 20 is of a flat design with a flat plate 22 having a fiber cathode element array 24 thereon. The transparent second flat plate 26 has a coating of the transparent conductor 28 on the surface of the flat plate 26 facing the cathode element array 24, and phosphor or cathodic light emission on the transparent conductor coating 28. A coating of material 30. The spacer plate 26 separates the plate 22 and the plate 26 and includes a vacuum-capable sealed container for the fiber cathode element array 24, the transparent conductor coating 28, and the phosphor or cathode light emitting material 30. to provide. Conductor electrodes are connected to the transparent conductor coating 28 and the fiber cathode element array 24.

In another embodiment of the invention shown in FIG. 3, the bulb-like light 40 has a glass globe having an inner coating of the transparent conductor 44 and a coating of the phosphor or cathode light emitting material 46. 42). The fibrous cathode element 48, the fibrous field emitter, is located within the glass sphere 42. The conductors are connected to the fiber cathode element 48 and to the transparent conductor coating or anode 44. The fiber cathode element 48 may consist of a single fiber or may comprise a plurality of fibers. In general, a single fiber or individual fibers that make up a plurality of fibers may have a diameter of about 1 micron to about 20 microns, preferably about 5 microns to about 10 microns.

In yet another embodiment of the present invention shown in FIGS. 4A and 4B, the illumination 50 capable of producing light beam output 52 includes reflector material 56, transparent conductive material 58, and phosphor or cathode. Hemispherical glass support 54 having a coating on the concave inner surface of luminescent material 60. The fibrous cathode element 62, the fibrous field emitter, is located in the glass hemisphere 54. The conductor is connected to the fiber cathode element 62 and the transparent conductor coating portion or the anode 58. By varying the shape of the glass support 54, a more concentrated light beam is produced. For example, a parabolic support will accomplish this result.

FIG. 5 shows a clear plastic, eg, Lucite, covered with end caps 72 and 74 to form a vacuum seal. ) Shows a simple test apparatus used to examine field emission parameters of fiber cathodes, including plastic tubes 70. End cap 72 includes an opening 76 connected to a vacuum pump. Ground copper screen mesh 78 coated with phosphor or cathode luminescent material 80 is suspended in a vacuum sealed container. The fiber cathode element 82 is located in the grounded copper screen mesh 78. The conductors are connected to the fiber cathode element 82 and the copper screen mesh or anode 78. This test apparatus can demonstrate whether it is useful for determining the release uniformity of the release fiber.

6 shows a current limiting circuit used in the lighting apparatus of the present invention. The current limiting circuit 90 includes a resistor 92 and an inductor 94 in series with the emitting fiber or fiber cathode element 96. The power source 98 is connected to the anode 102 and the current limiting circuit 90 in series with the cathode element 96 via a rectifying voltage step-up circuit 100.

In another embodiment of the invention shown in FIG. 7, the illumination 120 is formed from a standard light bulb with a threaded base. The inner surface of the glass bulb 121 is coated with a transparent conductive oxide 122 and a phosphor or a cathode light emitting material 123. The fiber cathode field emitter, consisting of the field emission electron emission fibers 124, is in the central region of the bulb. The fiber radiator is shown in a triangular structure but may be other structures, for example circular or figures having four or more sides. Fiber emitters are supported by non-emitting current carriers 125. The emitted electrons are shown by arrow 126. Threaded base 127 is essentially the same as that used in standard incandescent bulbs.

In operation of the lighting device of the present invention, a power density of about 1.5 watts per inch from the cathode may generally be required to produce sufficient electron emission. In general, when the bias voltage on the fiber cathode is at least 1500 volts, the emission current per inch should be at least about 1 mA.

The invention is described in more detail in the following examples which are intended for illustrative purposes only.

[Example 1]

The lighting device is basically assembled as shown in FIG. 5 using carbon fibers exposed to a single high intensity ion beam treatment. Carbon fiber was prepared as follows.

Untreated graphite fibers from the graphite yarn (IM7 graphite fibers commercially available from Hercules, Inc., Wilmington, DE) were developed through the frame, and the frame located in the path of the strong ion beam was released in October 1993 by Rej et al. Rev. Sci. Instrum. 64 (10), pp.2753-2760. The voltage is about 300 kW. The distance of the frame from the focus of the ion beam varies between about 6 inches and 18 inches. The energy density of the ion beam is estimated to be about 2 J / cm 2 to about 10 J / cm 2. The pulse time of the ion beam is about 1 ms. After one pulse, the frame rotates (180 °) and the opposite side of the fiber is exposed to a single pulse of a strong ion beam. The resulting fibers are tested and proved to be good field emission electron emitters.

The fibers are attached to the conductor "A" shown in FIG. Zinc Oxide: Zinc phosphor is coated on copper mesh screen. A potential difference of about 3.5 keV is applied to the cathode and anode, i.e., conductors "A" and "B". A current of 2-3 kW can be obtained on the 1 inch (2.5 cm) length of the fiber with permanent light emission. About 10 watts per inch (2.5 cm) is obtained for illumination.

Although the invention has been described with reference to the detailed description, it should not be construed as limiting the scope of the invention, but rather should be included within the scope of the appended claims.

Claims (13)

In the lighting apparatus, A fibrous cold cathode field emitter comprising at least one fiber, the fibrous cold cathode field emitter comprising: a fibrous cold cathode field emitter having a diameter of at least one fiber of the fibrous cold cathode of less than about 100 microns; An anode for sucking electrons emitted by the fiber cold cathode field emitter; A phosphor capable of generating permanent light upon contact with electrons emitted from the fiber cold cathode field emitter; And About 10 including the fiber cold cathode field emitter, anode and phosphor therein, provided that electron emission from the fiber of the fiber electrode occurs along the length of the fiber used and not at the fiber tip or end. Evacuated enclosure smaller than ^-5 Torr Lighting device comprising a. The lighting device of claim 1, wherein the one or more fibers have a diameter of about 1 micron to about 15 microns. The lighting device of claim 1, wherein the fiber cold cathode field emitter comprises one or more fibers. The lighting device of claim 3, wherein the fibers have a diameter of about 1 micron to about 15 microns. The lighting device of claim 1, wherein the vacuum seal is globular. The lighting device of claim 1, wherein the vacuum seal is hemispherical. The lighting device of claim 3, wherein the vacuum seal is spherical. The lighting device of claim 3, wherein the vacuum seal is hemispherical. The lighting device of claim 1, wherein the vacuum seal is in a flat plate shape. The illuminating device according to claim 3, wherein the vacuum sealing part is flat. The lighting device of claim 1, wherein the vacuum seal is cylindrical. The lighting device of claim 3, wherein the vacuum seal is cylindrical. 2. A lighting device according to claim 1, wherein said device is free of mercury.