KR20080096423A - Fluorescent lamp - Google Patents

Abstract

A fluorescent lamp is provided to coat an electrode with a radioactive substance formed of ion crystal. A fluorescent lamp(21) comprises a light transmission tube(22) in which Hydrargyrum and rare gas are sealed up; a phosphor layer coated onto the inside of light transmission tube; and radioactive substance which is formed of ion crystal and coated on the surface of electrode and periphery region of electrode. The ion crystal contains one among the sulfate, and the halogenoid or the carboxylic acid salt.

Description

Fluorescent Lamp {FLUORESCENT LAMP}

The present invention relates to a fluorescent lamp, specifically, a fluorescent lamp having excellent lighting characteristics.

Cold cathode fluorescent lamps and external electrode fluorescent lamps include a light source for reading an image of a backlight, a facsimile, and the like of a liquid crystal display unit used in a television set and a computer, an eraser light source of a copier, and various kinds of Used in the display unit. In a cold cathode fluorescent lamp, an electrode is provided near two ends in an interior of a light transmitting tube, such as glass, in which mercury and rare gas are sealed and a phosphor layer is provided on the inner surface. In an external electrode fluorescent lamp, the electrode provided inside the light transmitting tube in the cold cathode fluorescent lamp is provided on the peripheral surface of both ends of the light transmitting tube, thereby extending the life of the electrode. In the cold cathode fluorescent lamp and the external electrode fluorescent lamp as described above, the electrons present in a small amount inside the light transmitting tube ionize the rare gas when a voltage is applied across the electrode. The ionized rare gas is attracted by the electrode and causes secondary electrons to be released, resulting in a glow discharge. Mercury excited by this glow discharge emits ultraviolet rays. Cold-cathode fluorescent lamps and external electrode fluorescent lamps use fluorescence emitted by phosphors that are subjected to ultraviolet radiation and are excited. In this type of fluorescent lamp, in a dark state, it takes a long time until the emission of secondary electrons occurs after the application of the starting voltage across the electrode, so that the fluorescent lamp does not immediately turn on. Therefore, by applying a radioactive material having a high secondary electron emission coefficient, such as a cesium compound, on the inner surface of the end of the glass bulb, cesium causes secondary electrons to facilitate the generation of discharge upon lighting. A report exists (Japanese Patent Laid-Open No. 2001-15065).

In addition, the report is radioactive as a result of electron discharge electrodes (Japanese Patent Laid-Open No. 2001-332212) and discharges having extended lifetimes by using radioactive materials formed by combining carbonates such as alkaline earth metals and oxides such as rare earth metals. A fluorescent lamp in which a radioactive material is provided at a position far from the phosphor film in order to prevent cesium separated from the cesium compound used as the substance to adhere to the phosphor film and reduce the translucency of the phosphor film (Japanese Patent Laid-Open No. 2006-19100 ).

It is an object of the present invention to provide a fluorescent lamp having excellent dark lighting properties.

The inventors have examined a variety of radioactive materials and found what can be used in fluorescent lamps. As a result, the inventors found that by using ion crystals, a fluorescent lamp having excellent dark lighting characteristics can be obtained. The inventor finally completed the present invention based on this knowledge.

That is, the present invention includes a light transmitting tube in which mercury and a rare gas are sealed, a phosphor layer provided on an inner surface of the light transmitting tube, and a pair of electrodes, and a radioactive material formed of ion crystals is formed on the electrode surface or around the electrode. A fluorescent lamp provided.

The fluorescent lamp of the present invention has excellent dark lighting properties.

This application claims priority based on Japanese Patent Application No. 2007-116647 filed on April 26, 2007, the disclosure of which is incorporated herein by reference in its entirety.

The fluorescent lamp of the present invention has excellent dark lighting properties.

The fluorescent lamp of the present invention includes a light transmitting tube in which mercury and a rare gas are sealed, a phosphor layer provided on an inner surface of the light transmitting tube, and a pair of electrodes, and a radioactive material formed of ionic crystals is formed on an electrode surface or It is a fluorescent lamp provided near the electrode.

As the light transmitting tube used in the fluorescent lamp of the present invention, those made of any material, such as a light transmitting tube made of glass, may be used as long as it is made of a material through which visible light passes. Light transmitting tubes having any shape, such as straight tubular, curved, annular and valve-shaped, having a circular cross-sectional shape or an elliptical cross-sectional shape may be used.

The rare gas sealed inside the light transmitting tube is ionized by electrons present in a small amount inside the light transmitting tube when the starting voltage is applied to the electrode, the ions of the rare gas collide against the electrode and the radioactive material to be described later, and the rare The gas has a function of emitting secondary electrons. For example, argon and neon can be used as rare gas. The amount of rare gas used to seal inside the light transmitting tube may be, for example, 30 to 100 Torr.

Mercury sealed inside the light transmitting tube is excited by the glow discharge generated by the secondary electrons formed by the rare gas described above to generate ultraviolet light having a wavelength of 253.7 nm. The amount of mercury sealed inside the light transmitting tube may be such that the vapor pressure is, for example, 1 to 10 Pa when the fluorescent lamp is lit.

The phosphor layer is provided on the inner surface of the above-mentioned light transmitting tube. The phosphor layer includes a phosphor that emits visible light by receiving an ultraviolet light or the like of 253.7 nm wavelength emitted from mercury. Phosphors which are hardly damaged by heat and which hardly absorb mercury are preferred. In some cases, a high mercury vapor pressure condition continues upon ignition of the fluorescent lamp, but even in this case, it is desirable that the amount of mercury absorbed by the phosphor is small and therefore damage to the light transmitting tube can be avoided. Examples of such phosphors include Y ₂ O ₃ : Eu, YVO ₄ : Eu, LaPO ₄ : Ce, Tb, (Ba, Eu) MgAl ₁₀ O ₁₇ , (Ba, Sr, Eu) (Mg, Mn) Al ₁₀ O ₁₇ , Sr ₁₀ (PO ₄ ) ₆ C ₁₂ : Eu and (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ C ₁₂ : Eu. In addition, the phosphor layer includes a suitable combination of phosphors that are excited by ultraviolet radiation of 253.7 nm wavelength emitted from mercury and emit visible light in the green, red and blue regions so that the phosphor layer has excellent color rendering and white light. Ensure to radiate. The thickness of the phosphor layer may be, for example, 15 to 30 nm.

The above-mentioned fluorescent lamp is provided with a pair of electrodes as a means for causing the generation of a discharge, which discharge is for causing ultraviolet radiation from the above-mentioned mercury atom. Both cold cathode and external electrodes can be used as such electrodes. Examples of the former include a cold cathode in which a cup-shaped electrode formed of nickel, molybdenum or the like is arranged near two end portions of the inside of the light transmitting tube with the openings facing each other. For external electrodes, alloy foils such as aluminum, iron, and nickel can be used on the peripheral surfaces of both end portions of the light transmitting tube through conductive adhesives such as silicon resins in which metal particles and the like are mixed, solder, and the like.

Radioactive materials used in fluorescent lamps are formed of ionic crystals. Ionic crystals are crystals that form when anions and cations aggregate, mainly due to the attraction of static electricity. Examples of ionic crystals are given anionic ionic crystals, including inorganic acid salts such as sulfates, hydrochlorides, hydrofluorides, hydrobromides such as hydrobromide, hydrochlorides such as iodates, organic acid salts such as nitrates and carbonates and carboxylic acids, and the like. . These anions can emit secondary electrons in fluorescent lamps. Preference is given to anions consisting of relatively large atoms and groups of atoms. The cation which performs ionic bond with these anions is not limited to low work function metal ions, and may consist of arbitrary metal ions and atomic groups of metal ions. These cations may be any ions such as alkali metals, alkaline earth metals, rare earths and transition metals. In addition, examples of the ionic crystals include metal oxides and metal hydroxides. Specifically, halogenated compounds such as potassium sulfate, sodium sulfate, calcium sulfate, magnesium sulfate, barium sulfate, iron sulfate, calcium fluoride, magnesium fluoride, calcium chloride, magnesium chloride and carboxy calcium salt, carboxy magnesium salt and The same carboxylate etc. can be mentioned. In addition, calcium oxide, magnesium oxide, barium oxide, lanthanum oxide, lanthanum hydroxide and the like can be enumerated.

In order to form a radioactive material with such ionic crystals, a coating liquid containing ionic crystals is prepared, and the coating liquid is applied to the inner surface or the electrode surface of the light transmitting tube near the electrode, thereby providing this coating liquid as a coating film. Can be. Examples of the medium used in the coating liquid include water, alcohols such as ethanol, organic solvents such as butyl acetate and xylene, and mixtures thereof. As the application method, any of coating, immersion, spray application can be adopted. After application of a coating liquid of a predetermined thickness, the coated film can be dried by blowing hot air. The amount of radioactive material that can be used is for example 1 mg or less per electrode. It is also possible to provide the radioactive material to the inner surface or the electrode surface of the light transmitting tube near the electrode surface by methods such as thermal spraying and deposition.

Such a fluorescent lamp can be manufactured, for example, by the following method. A liquid containing a phosphor is prepared, and this liquid is applied to the inner surface of the light transmitting tube by a method such as application, immersion and spraying, and the coated film is dried, thereby providing a phosphor layer. Thereafter, the coating liquid provided by using the ion crystals is applied to the inner wall surface or the electrode surface near the region where the electrodes of the light transmitting tube are arranged, and the coated film is dried, thereby providing a layer of radioactive material. Thereafter, electrodes to which the conductive wires are connected are arranged at both ends of the light transmitting tube and the ends are sealed with a cap or the like. Thereafter, rare gas and mercury are sealed inside.

1 shows an example of the fluorescent lamp of the present invention applied to a cold fluorescent lamp. In the cold cathode fluorescent lamp 1 shown in the schematic cross-sectional view of FIG. 1, both ends of the glass tube 22 made of borosilicate glass are hermetically sealed with bead glass 23. The outer diameter of the glass tube 22 may, for example, be in the range of 1.5 to 6.0 nm, preferably in the range of 1.5 to 5.0 nm. On the inner wall surface of the glass tube 22, a phosphor layer 24 is provided substantially along the entire length of the glass tube. In the internal space 24 of the glass tube 22, the internal pressure is reduced by several tens of atmospheric pressure so that a rare amount of rare gas and mercury are injected into this space. Near both ends of the glass tube 22, for example, cup-shaped electrodes 27 formed of nickel, molybdenum, or the like having an outer diameter of 0.7 to 3.5 mm and a thickness of 0.05 to 1.0 mm, respectively, have openings 20 facing each other. Arranged in a closed state. Each lead 29 is provided in such a way that one end is welded to the bottom of the electrode 27 and the other end penetrates through the bead glass 23 and exits out of the glass tube 22.

The light transmitting tube electron emitting layers 22a, 22b containing the above-mentioned radioactive material are provided on the inner surface of the glass tube 22 near both electrodes. Since the electron emitting layers 22a and 22b are not easily sputtered by rare gas and mercury during discharge, the light transmitting tube electron emitting layers 22a and 22b transmit light toward the terminal closer to the terminal than the opening position of the cup-shaped electrode 27. It is preferably provided on the inner surface of the tube. The thickness of each light transmitting tube electron emitting layer is in the range such that the amount of radioactive material used is, for example, 1 mg or less on one side. An electron emission layer made of a similar material may also be provided on the surface of the cupped electrode 27. The electron emitting layer may be provided on either the outside or the inside of the cup. However, since the electrode electron emitting layers 27a and 27b are not easily sputtered during discharge, the electrode electron emitting layers 27a and 27b are preferably provided on the inner surface of the cup. The thickness of each electrode electron-emitting layer 27a, 27b is on the order of a range such that the amount of radioactive material used is, for example, 1 mg or less per electrode. For these electron emitting layers, only one of the light transmitting tube electron emitting layer and the electrode electron emitting layer may be provided, and only one of the light transmitting electron emitting layers 22a and 22b may be provided, and the electrode electron emitting layer 27a , Only one of 27b) may be provided.

2 (a) and 2 (b) show an example of the fluorescent lamp of the present invention applied to an external electrode fluorescent lamp. The external electrode type fluorescent lamp 31 shown in the side view and the schematic sectional view of Figs. 2A and 2B is a glass tube 32 made of borosilicate glass, whose ends are hermetically sealed, respectively. Has The outer diameter of the glass tube 32 can be, for example, in the range of 1.5 to 6.0 mm, preferably in the range of 1.5 to 5.0 mm. On the inner wall surface of the glass tube 32, a phosphor layer 33 is provided substantially along the entire length of the glass tube. In the interior space of the glass tube 32, the internal pressure is reduced by several tens of atmospheric pressure so that a rare amount of rare gas and mercury are injected into this space. The external electrode 34 is provided on the peripheral surface of each of the terminal portions of the glass tube 32. As the external electrode 34, a metal foil such as aluminum and nickel is bonded to the outer surface of the glass tube 32 as a conductive adhesive in which the metal powder is mixed with the silicone resin and provided to cover the entire terminal of the glass tube 32. May be The longitudinal length L2 of the external electrode can be 10 to 35 mm, for example. A conductor, not shown, is connected to the external electrode so that a voltage can be applied to the electrode through the conductor.

In such an external electrode fluorescent lamp, an electron emission layer 32a containing the above-mentioned emitting material is provided near both electrodes. Since the number of metal atoms sputtered from the electron emitting layer during discharge is reduced, and it is possible to suppress the decrease in the transmittance of fluorescence emitted from the phosphor due to the adhesion of the metal atoms sputtered to the phosphor layer, 32a) is preferably provided on the inner surface of the glass tube 32 at a distance L1 from the end of the phosphor layer and closer to the terminal than the central point at which the external electrode 34 is provided. The thickness of the electron emitting layer may be in the range such that the amount of radioactive material specifically used is 1 mg or less per electrode.

In the above-described cathode fluorescent lamp and external electrode fluorescent lamp, a layer of radioactive material formed of ion crystals is provided near the electrode or on the surface of the electrode. Therefore, glow discharge is immediately generated by the secondary electrons within a short time within 0.5 seconds immediately after the application of the start voltage and the lighting of the fluorescent lamp.

Example

The invention will be explained in more detail below on the basis of examples. However, the technical scope of the present invention is not limited to these examples.

First embodiment

The cold cathode fluorescent lamp shown in Fig. 1 was manufactured by the following method. A liquid containing a phosphor is prepared, and this liquid is applied to an inner surface of a light transmitting tube made of borosilicate glass having a diameter of 2.4 mm and a thickness of 0.2 mm, and the applied liquid is dried, whereby a phosphor having a thickness of 20 nm A layer was provided. Thereafter, the coating liquid prepared by dispersing the ionic crystals shown in Table 1 in water, ethanol or a mixture thereof is formed as nickel, with a diameter of 1.7 mm and a thickness of 0.3 mm, at the bottom where the conductor wires are connected in advance. Was applied to the inner surface of the, and the applied liquid was dried at 150 ° C., so that the electron-emitting layer was provided so that the amount of ionic crystals was 1 mg or less. These electrodes were arranged at each of both ends of the light transmitting tube and heated by a burner using bead glass through which the conducting wires were sealed, thereby sealing both ends of the light transmitting tube. Thereafter, argon gas, neon gas and mercury were sealed therein, thereby producing a cold cathode fluorescent lamp.

These cold cathode fluorescent lamps were produced in a quantity of 25, and the number of cold cathode fluorescent lamps to be lit within 0.5 seconds was confirmed. The results are shown in Table 1.

As a comparative example, a cold cathode fluorescent lamp was produced in the same manner as in the first embodiment except that no electron emitting layer was provided, and the lighting test was similarly performed.

Second embodiment

The external electrode type fluorescent lamp shown in Figs. 2A and 2B was manufactured by the following method. A phosphor layer similar to that used in the first example was provided on the inner surface of the glass tube made of borosilicate glass, with a diameter of 4.0 mm and a thickness of 0.5 mm. Then, a coating liquid prepared by dispersing the ionic crystals shown in Table 1 in water, ethanol or a mixture thereof is applied to the inner surface of the glass tube, and the applied liquid is dried at 50 to 100 ° C., whereby the electron emitting layer is Was provided. Thereafter, both ends of the glass tube were sealed, and argon gas, neon gas and mercury were sealed therein, thereby producing an external electrode type fluorescent lamp.

These external electrode fluorescent lamps were produced in a quantity of 25, and the number of cold cathode fluorescent lamps lighting up within 0.5 seconds was confirmed. The results are shown in Table 1.

As a comparative example, an external electrode fluorescent lamp was produced in the same manner as in the second embodiment except that no electron emitting layer was provided, and the lighting test was similarly performed.

Table 1

 Ionic crystals Na ₂ SO ₄ K ₂ SO ₄ MgSO ₄ CaSO ₄ BaSO ₄    none  First embodiment     20     25     17     18     15     6  Second embodiment     23     24     20     16     16     4

1 is a schematic cross-sectional view of a cold cathode fluorescent lamp, which is an application example of the fluorescent lamp of the present invention.

2 (a) and 2 (b) are side and schematic cross-sectional views of an external electrode fluorescent lamp, which is another application example of the fluorescent lamp of the present invention, respectively.

<Explanation of symbols for the main parts of the drawings>

20: opening

21: cold cathode fluorescent lamp

22: glass tube

22a, 22b: light transmitting tube electron emitting layer

23: bead glass

25: interior space

27: cup type electrode

29: lead wire

Claims (2)

A light transmitting tube sealed with mercury and a rare gas, A phosphor layer provided on an inner surface of the light transmitting tube, Including a pair of electrodes, A fluorescent lamp provided with a radioactive material formed of ion crystals on the surface of the electrode or around the electrode. The fluorescent lamp of claim 1, wherein the ion crystals contain one or more selected from sulfate, halogenate or carboxylate.

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