Patent Application
20130175918
The present invention belongs to the technical field of electric light source, and particularly relates to a field emission anode plate, a field emission light source and a method for preparing the same.
Electric light sources have long been a research hotspot all over the world, and occupy a very important position in the world economy. At present, a widely used light source is gas-discharge light source, and the mechanism thereof comprises evacuating the light bulb and charging it with mixed gases containing mercury so that the discharge of gases leads to light emission or UV lights produced by the discharge of gases excite the fluorescent powder to emit lights. However, the pulsed light emitted by the gas-discharge light source readily leads to visual fatigue. In addition, mercury pollutes the environment. Along with the progress of the society and science and technology, it has become an important research topic to develop a clean light source which is energy efficient and environment friendly to replace conventional light sources.
Field emission light source is one type of newly developed electric light source, and has the advantages of high current density, low power consumption, and quick response, and therefore has an important application prospect in vacuum electronic fields such as flat-panel display, X ray source, microwave amplifier, etc. The mechanism thereof comprises that an electron emitter, such as a tip of a metal, carbon nanotubes, etc., at a positions having a low potential emits electrons under the effect of an electric field to bombard a fluorophor at a position having a high potential to render it emitting visible lights.
Currently, field emission devices are mainly used in illumination and display fields, and have advantages such as low working voltage, void of preheating delay, high integration, energy saving, environment friendliness, quick start-up, low weight and thickness and good environment adaptability. As a new-generation light source in the illumination field, field emission devices have the advantages of void of mercury, low energy consumption, homogeneous luminescence and adjustable light intensity, and therefore have become the interest of more and more researchers in the illumination field and received rapid progress in the illumination industry. Currently used field emission devices mainly use a fluorescent powder as the anode, wherein electrons bombard the fluorescent powder to render it emitting visible lights under the excitation of the electron beam. Normally, in field emission devices comprising a fluorescent powder, a fluorescent powder of sulfide, oxide or silicate type may be selected as the anode luminescent material. An oxide or silicate type of fluorescent powder has relatively low conductivity, and electric charges would readily accumulate at the anode under the bombardment of the electron beam, which leads to decrease of the electric potential difference between the two electrodes and affects the luminescent efficiency of the device. For an anode plates made from a sulfide fluorescent powder which has relatively better conductivity, the sulfide would readily decompose to release gases under long time excitation of electron beam, which not only decreases the vacuum degree of the device, but also “poisons” the cathode, which finally reduces the service life of the device. In addition, when using powders as the field emission anode, the powders may peel off under the bombardment of the electron beam, which leads to the masking of the cathode of the device and heterogeneous luminescence of the anode, and reduces the service life of the device.
The objectives of the present invention are to overcome the above shortcomings in the prior art and to provide a field emission anode plate having good conductivity, high light-transmittance, and stable resistance to the impact of electrons.
In addition, it is provided a field emission light source comprising the above field emission anode plate.
The present invention also provides a method for preparing the above field emission light source.
In order to achieve the above objectives, the technical solutions of the present invention are as follows.
A field emission anode plate comprises a transparent ceramic base and an anode conductive layer provided on a surface of the transparent ceramic base, and the transparent ceramic base emits light under excitation of cathode rays.
In addition, a field emission light source comprises a field emission anode plate, a field emission cathode plate and a supporter, wherein the field emission anode plate is the above component; the field emission cathode plate comprises a substrate and a cathode conductive layer provided on a surface of the substrate; the anode conductive layer and the cathode conductive layer are arranged opposing each other; two ends of the supporter are hermetically connected to the field emission anode plate and the field emission cathode plate, respectively; and the supporter, the field emission anode plate and the field emission cathode plate form a vacuum chamber.
A method for preparing the above field emission light source comprises the steps of:
preparing a field emission anode plate, a field emission cathode plate and an insulating supporter, wherein the field emission anode plate comprises a transparent ceramic base and an anode conductive layer provided on a surface of the transparent ceramic base, wherein the transparent ceramic base emits light under excitation of cathode rays; and the field emission cathode plate comprises a substrate and a cathode conductive layer provided on a surface of the substrate;
arranging the anode conductive layer of the field emission anode plate and the cathode conductive layer of the field emission cathode plate opposing each other; and
connecting two ends of the insulating supporter to the field emission anode plate and the field emission cathode plate, respectively, so that the supporter, the field emission anode plate and the field emission cathode plate form a vacuum chamber; and
arranging an exhaust port at the chamber, applying low-melting-point glass solder at a joint of the insulating supporter, the field emission anode plate and the field emission cathode plate, heating to seal, exhausting the chamber, and sealing the exhausting port to obtain the field emission light source.
The field emission anode plate of the present invention employs a transparent ceramic which may emit light under the excitation of cathode rays as a base. This transparent ceramic base effectively increases the light-transmittance and resistance to the impact of electrons of the field emission anode plate, improves the stability, corrosion resistance and abrasive resistance of this anode plate. In addition, the field emission anode plate emits light homogeneously and has a low cost. The field emission light source made from the field emission anode plate shows high luminescent intensity, homogeneous luminescence, stable luminescent performance, corrosion resistance, abrasive resistance, and long service life. The method for preparing the field emission light source is simple with high production efficiency and low cost and is suitable for industrial production.
In order to make the objectives, the technical solutions and the advantages of the present invention more obvious, the present invention will be further described in detail in combination with the Figures and the embodiments. It shall be understood that the specific embodiments described herein are only to illustrate rather than to limit the present invention.
An embodiment of the present invention provides a field emission anode plate 1 which has good conductivity, high light-transmittance, and stable resistance to the impact of electrons. As shown in
Specifically, the material of the transparent ceramic base 10 in the above embodiment is preferably one of Y2O3:Eu transparent ceramic, Y2O2S:Eu transparent ceramic, Y2SiO5:Tb transparent ceramic, Gd2O2S:Tb transparent ceramic, LaAlO3:Tm transparent ceramic and LaGaO3:Tm transparent ceramic. The transparent ceramics with this kind of materials have high light-transmittance, high stability, and good resistance to the impact of electrons, and have good corrosion resistance and good abrasive resistance.
Furthermore, the transparent ceramic base 10 of this embodiment has a thickness of preferably 0.5-30 mm. The transparent ceramic base 10 with such a thickness has an effective crush resistance and mechanical resistance. When the thickness increases, the crush resistance and mechanical resistance would increase accordingly; however, too high a thickness would impair the appearance of the transparent ceramic base 10, increase the weight thereof as well as the production cost thereof. The anode conductive layer 11 has a thickness of preferably 10 nm-300 μm, and the material thereof is preferably metal aluminum, silver, magnesium, copper or gold. The thickness of the anode conductive layer 11 determines the electron-penetrating efficiency, the surface resistance of the conductive layer, as well as the luminescent efficiency of the field emission light source. When the thickness of the anode conductive layer 11 increases, the surface resistance would decrease accordingly, but the electron-penetrating efficiency as well as the luminescent efficiency of the field emission light source would also decrease. If the thickness is too high, electrons cannot penetrate, leading to decrease of the luminescent efficiency of the field emission light source. Accordingly, the above thickness of the anode conductive layer 11 may effectively balance the surface resistance and the electron-penetrating efficiency of the field emission anode plate 1, and optimize the performance of the field emission anode plate 1. The above materials of the anode conductive layer 11 have superior electron-penetrating efficiency, so that the luminescent efficiency of the field emission light source is increased.
An embodiment of the present invention also provides a field emission light source made from the above field emission anode plate 1. As shown in
Specifically, in the above embodiment of the field emission light source, the distance between the field emission anode plate 1 and the field emission cathode plate 2 is preferably 200 μm-3 cm. The range of the distance can effectively ensure that electrons penetrate the anode conductive layer 11 of the field emission anode plate 1, and increase the luminescent efficiency of the field emission light source.
Furthermore, the substrate 20 of the above field emission cathode plate 2 comprises a surface body 201, which is arranged opposing the above anode conductive layer 11. On the surface body 201 is provided the cathode conductive layer 21. The thickness of the substrate 20 is preferably 0.5-30 mm. The substrate 20 ensures the crush resistance and mechanical resistance of the field emission cathode plate 2, and provides a supportive body for the cathode conductive layer 21. The cathode conductive layer 21 of the field emission cathode plate 2 comprises a conductive layer 210 provided on the surface body 201 and a cathode layer 211 provided on the outer surface of the conductive layer 210. The conductive layer 210 functions mainly for conducting, and has a resistance of preferably above 0 ohm and less than or equal to 7 ohm. The cathode 211 functions as an electron emitter, and provides a stable electron flow oriented to the anode conductive layer 11. Of course, the substrate 20 may also be provided with multiple surface bodies. Two ends of the above supporter 3 are hermetically connected to the field emission anode plate 1 and the field emission cathode plate 2, respectively, in the following ways.
The first way: referring to
The second way: referring to
The third way (not shown): two ends of the supporter 3 are hermetically connected to the transparent ceramic base 10 outer surface of the field emission anode plate 1 and the cathode conductive layer 21 outer surface of the field emission cathode plate 2, respectively, and the anode conductive layer 11 and the cathode layer 211 are both in the vacuum chamber 4. Alternatively, two ends of the supporter 3 are hermetically connected to the anode conductive layer 11 outer surface of the field emission anode plate 1 and the substrate 20 outer surface of the field emission cathode plate 2, respectively, and the cathode conductive layer 21 is in the vacuum chamber 4.
Specifically, the above conductive layer 210 is preferably one of tin indium oxide layer, silver layer, metallic aluminum layer, gold layer and chromium layer, and its thickness is preferably 100 μm-250 nm. The cathode layer 211 is preferably one of carbon nanotube layer, zinc oxide nanowire layer and cupric oxide nanowire layer, and its thickness is preferably 0.5-30 μm.
An embodiment of the present invention further provides a method for preparing the above field emission light source, and the flow chart of the method is shown in
S1. providing a field emission anode plate 1 (see
S2. arranging the anode conductive layer 11 of the field emission anode plate 1 and the cathode conductive layer 21 of the field emission cathode plate 2 opposing each other; and connecting two ends of the insulating supporter 3 to the field emission anode plate 1 and the field emission cathode plate 2, respectively, so that the supporter 3, the field emission anode plate 1 and the field emission cathode plate 2 form a vacuum chamber 4; and
S3. arranging an exhaust port (not shown in the Figures) at the chamber 4, applying low-melting-point glass solder at a joint of the insulating supporter 3, the field emission anode plate 1 and the field emission cathode plate 2, heating to seal, exhausting the chamber 4, and sealing the exhausting port to obtain the field emission light source.
Specifically, in step S1 of the above method for preparing the field emission light source, the materials and the thicknesses of the transparent ceramic base 10, the anode conductive layer 11, the substrate 20 and the cathode conductive layer 21 are the same as described above, and will not be repeated for conciseness. The insulating supporter 3 is preferably washed in advance, for example with acetone, ethanol and de-ionized water. The processes for obtaining the field emission anode plate 1 and the field emission cathode plate 2 are as follows.
The field emission anode plate 1: providing a transparent ceramic base 10 (see
The field emission cathode plate 2: providing a substrate 20 (see
In the above processes for obtaining the field emission anode plate 1 and the field emission cathode plate 2, the transparent ceramic base 10 and the substrate 20 are preferably washed with acetone, ethanol and de-ionized water, or the like; and may be dried by air-drying, oven-drying, or the like. The method for plating the surface of the transparent ceramic base 10 of the field emission anode plate 1 with the anode conductive layer 11 is preferably an evaporation method, a magnetron sputtering method, or the like. The material for the substrate 20 of the field emission cathode plate 2 may be any one commonly used in the art. The conductive layer 210, such as tin indium oxide layer, silver layer, metallic aluminum layer, gold layer or chromium layer, may be plated on the surface of the substrate 20 by an evaporation method or a magnetron sputtering method, and the method for plating the outer surface of the conductive layer 210 with the cathode layer 211, such as carbon nanotube layer, zinc oxide nanowire layer or cupric oxide nanowire layer, may be a printing method or a growing method.
Specifically, in step S2 of the above method for preparing the field emission light source, the ways in which two ends of the supporter 3 are hermetically connected to the field emission anode plate 1 and the field emission cathode plate 2 are described above and will not be repeated for conciseness.
Specifically, in step S3 of the above method for preparing the field emission light source, the temperature of heating to seal is preferably 380-550° C., and the time thereof may be 5-90 min. The above temperature and time may effectively ensure melting the low-melting-point glass solder and sealing of the joint of the insulating supporter 3, the field emission anode plate 1 and the field emission cathode plate 2. Exhausting the chamber 4 in this step is carried out through the exhaust port connected to the chamber 4. There may be two ways for arranging the exhaust port: 1) erectly arranging an exhaust tube on a small hole at a corner of the field emission cathode plate 2, sealing the joint and heating to seal the exhaust tube; 2) arranging an exhaust tube in a gap of the supporter 3 between the field emission anode plate 1 and the field emission anode plate 2, sealing the joint and heating to seal the exhaust tube. The pressure after exhaustion is preferably 1×10−5˜9.9×10−5 Pa. In order to obtain a relative high vacuum in the vacuum chamber 4, exhausting is preferably conducted by an exhausting station. In order to obtain a relative good vacuum chamber 4, a getter is preferably placed in the exhausting tube during exhausting.
The above method for preparing the field emission light source only requires sealing the relevant components as required and exhausting to obtain the final product. The process is simple, thereby increasing the production efficiency and decreasing the production cost, which is suitable for industrial production.
The present invention will be further described in detail in combination with specific examples.
A red-light-emitting field emission light source has a structure as shown in
The specific preparation method is as follows.
(1) Preparation of the field emission anode plate 1: cutting the Y2O3:Eu transparent ceramic base 10 into a 70×50×0.5 mm piece, polishing both the upper and lower surfaces, sonicating the Y2O3:Eu transparent ceramic base 10 in sequence with acetone, absolute ethanol and de-ionized water for 20 min, air-drying the washed Y2O3:Eu transparent ceramic base 10, and evaporation plating a layer of Al film on a surface of the Y2O3:Eu transparent ceramic base 10 as the anode conductive layer 11.
(2) Preparation of the field emission cathode plate 2: cutting the substrate 20 into a 70×60×0.5 mm piece, polishing both the upper and lower surfaces, sonicating in sequence with acetone, absolute ethanol and de-ionized water, air-drying, sputtering an ITO film conductive layer 210 on a surface thereof, and printing a CNTs film cathode layer 211 on the outer surface of the conductive layer 210.
(3) Sealing: connecting two ends of the supporter 3 to the transparent ceramic base 10 outer surface of the field emission anode plate 1 and a surface body 201 of the substrate 20 of the field emission cathode plate 2, so that the supporter 3, the field emission anode plate 1 and the field emission cathode plate 2 form a chamber 4, and the aluminum film anode conductive layer 11 and the CNTs film cathode layer 211 are arranged opposing each other; arranging an exhaust tube on a small hole at a corner of the field emission cathode plate 2, applying a formulated low-melting-point glass solder at the joint of the field emission cathode plate 2, the field emission anode plate 1 and the supporter 3, heating to 380° C. and maintaining the temperature for 90 min to seal; after the low-melting-point glass solder is cooled down and solidified, placing a getter in the exhaust port, placing in a exhausting station, exhausting the chamber 4 to 1×10−5 Pa, heating and sealing off to give the red-light-emitting field emission light source.
A green-light-emitting field emission light source has a structure as shown in
The preparation method is as follows.
(1) Preparation of the field emission anode plate 1: cutting the Y2SiO5:Tb transparent ceramic base 10 into a 70×50×25 mm piece, polishing both the upper and lower surfaces, sonicating the Y2SiO5:Tb transparent ceramic base 10 in sequence with acetone, absolute ethanol and de-ionized water for 30 min, air-drying the washed Y2SiO5:Tb transparent ceramic base 10, and magnetron sputtering a layer of silver film having a thickness of 100 μm on a surface of the Y2SiO5:Tb transparent ceramic base 10 as the anode conductive layer 11.
(2) Preparation of the field emission cathode plate 2: cutting the substrate 20 into a 70×60×25 mm piece, polishing both the upper and lower surfaces, sonicating in sequence with acetone, absolute ethanol and de-ionized water, air-drying, sputtering a chromium film conductive layer 210 having a thickness of 100 μm on a surface thereof, and printing a zinc oxide nanowire film cathode layer 211 having a thickness of 10 μm on the outer surface of the conductive layer 210.
(3) Sealing: connecting two ends of the supporter 3 to the anode conductive layer 11 outer surface of the field emission anode plate 1 and the cathode conductive layer 21 outer surface of the field emission cathode plate 2, and arranging the silver film anode conductive layer 11 and the zinc oxide nanowire film cathode layer 211 opposing each other, so that the supporter 3, the field emission anode plate 1 and the field emission cathode plate 2 form a chamber 4; arranging an exhaust tube in a gap of the supporter 3 between the field emission anode plate 1 and the field emission cathode plate 2, applying a formulated low-melting-point glass solder at the joint of the field emission cathode plate 2, the field emission anode plate 1 and the supporter 3, heating to 450° C. and maintaining the temperature for 30 min to seal; after the low-melting-point glass solder is cooled down and solidified, placing a getter in the exhaust port, placing in a exhausting station, exhausting the chamber 4 to 5×10−5 Pa, heating and sealing off to give the green-light-emitting field emission light source.
Preparation of a blue-light-emitting field emission device which has a structure similar to that described in Example 1, except that two ends of the supporter 3 are hermetically connected to the anode conductive layer 11 outer surface of the field emission anode plate 1 and the substrate 20 outer surface of the field emission cathode plate 2, respectively, and the cathode conductive layer 21 is in the vacuum chamber 4.
The preparation method is as follows.
(1) Preparation of the field emission anode plate 1: cutting the LaAlO3:Tm transparent ceramic base 10 into a 70×50×30 mm piece, polishing both the upper and lower surfaces, sonicating the LaAlO3:Tm transparent ceramic base 10 in sequence with acetone, absolute ethanol and de-ionized water for 30 min, air-drying the washed LaAlO3:Tm transparent ceramic base 10, and magnetron sputtering a layer of magnesium film a thickness of 300 μm on a surface of the LaAlO3:Tm transparent ceramic base 10 as the anode conductive layer 11.
(2) Preparation of the field emission cathode plate 2: cutting the substrate 20 into a 70×60×30 mm piece, polishing both the upper and lower surfaces, sonicating in sequence with acetone, absolute ethanol and de-ionized water, air-drying, sputtering an aluminum conductive layer 210 having a thickness of 350 nm on a surface thereof, and printing a cupric oxide nanowire film cathode layer 211 having a thickness of 30 μm on the outer surface of the conductive layer 210.
(3) Sealing: connecting two ends of the supporter 3 to the anode conductive layer 11 outer surface of the field emission anode plate 1 and the cathode conductive layer 21 outer surface of the field emission cathode plate 2, so that the supporter 3 and the field emission anode plate 1 and the field emission cathode plate 2 form a chamber 4; arranging the magnesium film anode conductive layer 11 and the cupric oxide nanowire film cathode layer 211 opposing each other with the distance therebetween being 3 cm; arranging an exhaust tube in a gap of the supporter 3 between the field emission anode plate 1 and the field emission cathode plate 2, applying a formulated low-melting-point glass solder at the joint of the field emission cathode plate 2, the field emission anode plate 1 and the supporter 3, heating to 550° C. and maintaining the temperature for 5 min to seal; after the low-melting-point glass solder is cooled down and solidified, placing in a exhausting station, exhausting the chamber 4 to 9.9×10−5 Pa, heating and sealing off to give the red-light-emitting field emission light source.
Described above are only preferred embodiments of the present invention, which are not intended to limit the present invention. All modifications, equivalent substitutions and improvements within the spirit and principle of the present invention shall be within the scope of the present invention.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CN2010/077312 | 9/26/2010 | WO | 00 | 3/11/2013 |
