JP2007250322A - Fluorescent lamp and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent lamp capable of surely stopping discharge at an end of life; and to provide a lighting device with the fluorescent lamp. <P>SOLUTION: The fluorescent lamp is characterized by including: a translucent glass bulb 3; a phosphor layer 2 formed on the inside surface of the glass bulb 3; a discharge medium filled in the glass bulb 3; a pair of inner wells 7 respectively introduced into an end of the glass bulb 3; and a filament 8 having support parts 8a supported to the pair of inner wells 7, a central part 8b formed between the support parts 8a, and outer ends 8c projecting to the outside relative to the support parts 8a, wherein an electron emitting substance 9 is supported to the central part 8b, and gas emission substances 10 emitting gas by forming negative electrode bright points are supported at the outer ends 8c. Since the gas emission substances 10 are supported at the outer ends 8c of the filament 8, discharge can be stopped by moving the negative electrode bright points to the outer ends of the filament 8 after the electron emission substance 9 is depleted, and by emitting the gas into a discharge space. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluorescent lamp and a lighting device including the fluorescent lamp.

  Conventionally, an electron-emitting material (emitter) that emits thermoelectrons is formed on the filament electrode of a fluorescent lamp. The electron radioactive substance is made of an oxide of an alkaline earth metal such as barium oxide. This electron-emitting material is activated by applying alkaline earth metal carbonate to a filament and then energizing between a pair of inner wells supporting the filament electrode to thermally decompose the carbonate. Is formed.

  By the way, if this carbonate is mistakenly attached to the inner wells, even if the carbonate of the filaments is thermally decomposed by energization between the inner wells, the temperature in the vicinity of the inner wells is as high as necessary for the thermal decomposition. Since it does not rise, it may remain in the carbonate state. If the remaining carbonate releases an impure gas while the lamp is lit, there will be a problem such as a failure. For this reason, conventionally, a leg portion to which no electron radioactive substance is attached is formed to a predetermined length from the inner wells. The leg portion was provided with a thickness of about 1 mm, and a filament was formed so that the electron-emitting material did not adhere to the inner wells.

On the other hand, when a fluorescent lamp enclosing a filament having such a leg portion is started by a cold start method, ions are concentrated on the leg portion when transitioning from glow discharge to arc discharge (during glow-arc transition), The leg part is sputtered. As a result, there is a problem that the leg portion is disconnected and the fluorescent lamp reaches the end of its life. Therefore, a fluorescent lamp is known in which the length of the leg portion is defined to be equal to or less than a predetermined length so that ions do not concentrate on the leg portion (see, for example, Patent Document 1).
JP 2003-168386 A

  In the fluorescent lamp of Patent Document 1, the discharge life may continue even when the cathode fall voltage rises due to the depletion of the electron-emitting material after reaching the lighting life. In particular, when the lamp is lit by the high-frequency lighting method, there is a possibility that problems such as melting of the base around the electrode occur due to abnormal heating of the electrode by continuing half-wave discharge.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fluorescent lamp capable of reliably stopping discharge at the end of its life and an illumination device including the fluorescent lamp.

  The fluorescent lamp according to claim 1, a translucent glass bulb; a phosphor layer formed on an inner surface of the glass bulb; a discharge medium sealed in the glass bulb; and an end portion in the glass bulb A pair of inner wells introduced into each of the above; a support portion supported by the pair of inner wells, a central portion formed between the support portions, and an outer end portion protruding outward from the support portion, And a filament electrode carrying a gas releasing material that emits gas when a cathode luminescent spot is formed at the outer end portion and a cathode luminescent spot is formed at the outer end portion.

  In the present invention and each of the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

  The discharge vessel may be formed of any material as long as visible light in a desired wavelength region generated by the phosphor layer can be transmitted to the outside. Such a discharge vessel can be formed of, for example, a glass material such as lead glass containing lead, lead-free glass substantially free of lead, soda lime glass, or quartz glass, and ceramics such as alumina.

  The discharge vessel includes a straight tube shape, an annular shape, a bent shape, and the like, but the shape is not particularly limited. Examples of the bent shape include a U shape, a double U shape, a triple U shape, and a bowl shape. The end of the discharge vessel can be sealed using, for example, a sealing member. When sealing using a sealing member, known stem structures, such as a flare stem and a button stem, can be adopted. Further, when the end of the discharge vessel is directly sealed without using a sealing member, a pinch seal or the like can be employed.

  The phosphor layer is formed on the inner surface of the discharge vessel. The “inner surface” includes both the case where it is directly formed on the inner surface of the discharge vessel or the case where it is indirectly formed on the inner surface of the discharge vessel via a protective film, a reflective film and the like.

  The filament electrode may be made of any material as long as it is conductive and can carry an electron-emitting substance. Examples of such a material include transition metals such as tungsten and tantalum.

  The filament electrode is formed by forming a high melting point conductive wire such as a tungsten wire in a coil shape. Among the coil shapes, a double coil shape is preferable and a triple coil shape is more preferable from the viewpoint of the amount of the electron radioactive substance supported.

  The inner wells may be made of any material as long as it is conductive. Examples of such a material include iron-nickel alloy wires, copper wires, and dumet wires.

The electron-emitting material may be any material as long as it can easily emit thermoelectrons by heating the filament electrode. As such an electron-emitting substance, for example, a mixture of barium oxide (BaO), strontium oxide (SrO), calcium oxide (CaO), and the like is preferable. In addition, barium tantalate (BaTaO ₃ ), barium titanate (BaTiO ₃ ), barium zirconate (BaZrO ₃ ), strontium titanate (SrTiO ₃ ), strontium barium titanate (Ba _0.6 Sr _0.6 TiO ₃ ), etc. Can be used.

  The gas releasing substance is a substance that releases gas when a cathode bright spot is generated. For example, an alkaline earth metal carbonate can be used as a main component, and it is convenient if the material is before the pyrolysis of the electron emitting material.

  In the fluorescent lamp of the present invention, a cathode bright spot is formed in the electron-emitting material carried at the center of the filament in normal lighting. When the discharge continues even after the electron radioactive material is depleted, the electric field is concentrated on the outer end portion of the filament, so that the cathode bright spot is transferred to the outer end portion. And, since the gas releasing material carried on the outer end of the filament rises in temperature, the impure gas is released into the discharge space, so that the lighting sustaining voltage is increased by this impure gas, and the discharge can be stopped quickly. it can.

  According to a second aspect of the present invention, there is provided an illuminating device comprising: the fluorescent lamp according to the first aspect; a main body of the illuminating device to which the fluorescent lamp is attached; and a lighting device for lighting the fluorescent lamp.

  According to the fluorescent lamp of claim 1, since the gas emitting substance is supported on the outer end portion of the filament, the cathode bright spot is transferred to the outer end portion of the filament after the electron emitting material is depleted, and the gas emitting substance is By raising the temperature, the impure gas can be discharged into the discharge space to stop the discharge.

  According to the illuminating device of Claim 2, the illuminating device provided with the fluorescent lamp of Claim 1 can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a partially cutaway front view showing the entire fluorescent lamp according to the present embodiment, and FIG. 2 is an enlarged view of a main part showing electrodes of the fluorescent lamp according to the present embodiment.

  The fluorescent lamp 1 has a glass bulb 3 having a phosphor layer 2 formed on the inner surface, and a base 5 having a pair of connection pins 4 is sealed at both ends of the glass bulb 3. Further, both end portions of the glass bulb 3 are stem 6 and a pair of unillustrated outer wells connected to the pair of connection pins 4 respectively connected to the pair of connection pins 4, and connected to the outer wells and sealed and supported by the stem 6. An electrode 9 comprising a pair of inner wells 7 and 7 and a filament 8 supported by the inner wells 7 and 7 is sealed.

The filament 8 includes an electron-emitting material 9 made of barium oxide (BaO) at the central portion 8b formed between the support portions 8a and 8a, and barium carbonate (BaCO ₃ ) at the outer end portion 8c outside the support portion 8a. The gas releasing substance 10 is carried.

The phosphor to be used may be any material as long as it absorbs ultraviolet rays and emits visible light. Examples of such phosphors include divalent europium activated alkaline earth halophosphate phosphors, cerium and terbium co-activated lanthanum phosphate phosphors (LaPO ₄ : Ce, Tb), and trivalent europim. A three-wavelength phosphor such as an activated yttrium oxide phosphor (Y ₂ O ₃ : Eu), or a white phosphor such as a halophosphate phosphor can be used. The phosphor can be appropriately selected and used depending on the application.

  The discharge medium is composed of mercury and a rare gas. Mercury can be encapsulated in the form of amalgam or liquid mercury. As the amalgam, at least one metal selected from zinc (Zn), bismuth (Bi), indium (In), lead (Pb), tin (Sn), cadmium (Cd), silver (Ag), etc. And an alloy of mercury (Hg) can be used.

  Further, an auxiliary amalgam may be enclosed in the discharge vessel in order to quickly stabilize the luminous flux immediately after lighting. In this case, the auxiliary amalgam is preferably arranged at a position close to the discharge electrode.

  The rare gas is used for facilitating the start of discharge, and is generally not particularly limited as long as it does not pass through the discharge vessel. However, since neon (Ne) easily passes through quartz glass, When forming with quartz glass, argon (Ar), krypton (Kr), or xenon (Xe) is recommended. The rare gas may be a mixed rare gas. Note that the pressure of the rare gas is about 100 to 1000 Pa.

  Next, a method for manufacturing the electrode of the fluorescent lamp according to this embodiment will be described.

The inner wells 7 and 7 are held by the stem 6 so that the distance between the tips is 3.0 to 6.0 mm. The tip portions of the inner wells 7 and 7 are clamped, and the support portions 8a and 8a of the filament 8 are sandwiched between the inner wells 7 and 7, respectively. The filament 8 is formed in a triple coil shape, and the outer end is formed by a double coil having three or more turns. In this state, barium carbonate (BaCO ₃ ) is supported on the central portion 8b and the outer end portion 8c located between the support portions 8a and 8a. A leg portion having a width of 0.6 mm or less, preferably 0.2 to 0.5 mm is formed between the support portions 8a and 8a and the central portion 8b. The leg portion refers to a portion where nothing is supported on the filament. The reason why the width of the leg portion is defined as 0.6 mm or less is that ions are easily concentrated on the central portion 8b of the filament 8 within the above range. If the electron-emitting material 9 can be formed so that barium carbonate is not attached to the inner wells 7, 7, no barium carbonate is formed between the support portion 8a and the central portion 81b without providing a leg portion. The width of the region may be 0 mm. Next, the stem 6 is sealed at both ends of the glass bulb 3, and a current is passed between the inner wells 7 and 7 to heat the filament 8. Due to self-heating of the filament 8, the heat distribution of the filament 8 is the highest in the central portion 8b, but the temperature of the outer end portion 8a does not increase so much. Since an electric current flows through the central portion 8b so as to be about 1000 ° C., barium carbonate (BaCO ₃ ) is thermally decomposed at about 1000 ° C. and changed to barium oxide (BaO). As a result, barium oxide (BaO) 9 as an electron-emitting substance is formed in the central part 8b, and barium carbonate (BaCO ₃ ) 10 as a gas releasing substance remains in the outer end parts 8c and 8c without being decomposed. Become. In addition, since the outer end portions 8c and 8c have a temperature of 1000 ° C. or less while the fluorescent lamp is turned on, the barium carbonate (BaCO ₃ ) 10 is not decomposed and no impure gas is released. The gas releasing substance may be supported only on the outer end 8c on one side, but it is preferable to support the gas releasing substance on the outer ends 8c, 8c on both sides. Since it can form in such a structure by apply | coating one kind of carbonate to a separate area | region, manufacture is easy. Moreover, if the space | interval of the support parts 8a and 8a is 3.0-6.0 mm, the filament 8 can fully be heated up by electricity supply between the inner wells 7 and 7. FIG. For this reason, carbonate can be decomposed | disassembled reliably at the time of lamp manufacture, and metal oxides, such as barium oxide (BaO) which are the electron radioactive substances 9, etc. can be produced | generated. That is, the smaller the distance between the support portions 8a, the higher the temperature of the outer end portion 8c of the filament 8 when the inner wells 7, 7 are energized. Therefore, the fluorescent lamp of the present invention has a higher temperature of the filament 8 than the fluorescent lamp having a distance between the support portions 8a and 8a of greater than 6.0 mm, and the carbonate is reliably decomposed during manufacturing. On the other hand, when the distance between the support portions 8a and 8a is smaller than 3.0 mm, the outer end portion 8b of the filament 8 is excessively heated, so that it is difficult to manage the process so that the carbonate is not thermally decomposed. For this reason, it is preferable that the space | interval of the support part 8a is 3.0 mm or more.

  Next, the function and effect of the fluorescent lamp according to the present invention will be described.

The filament 8 supported by the inner wells 7 and 7 carries an electron-emitting substance 9 made of barium oxide (BaO) at the center 8b. For this reason, secondary electrons and thermal electrons are easily emitted. Therefore, when the transition from the glow discharge to the arc discharge occurs, even if ion concentration occurs in the central portion 8b of the filament 8, secondary electrons are emitted from the electron-emitting material 9, so that the filament 8 is prevented from being sputtered. Can do. Further, during the lighting of the fluorescent lamp, discharge is concentrated on the central portion 8b of the filament 8 to form a cathode bright spot. However, if the discharge continues even after the lighting life is reached and the electron radioactive material 9 is depleted, the cathode bright spot is transferred to the outer end 8c of the filament 8 where the electric field is concentrated. This phenomenon is likely to occur when the fluorescent lamp is lit at a high frequency of 10 kHz or more by the inverter device. At this time, if the work function of barium carbonate (BaCO ₃ ) is lower than that of the material of the filament 8 and the inner wells 7, a cathode bright spot is likely to be formed at the outer end 8c. The temperature of the filament cathode bright spot rises to about 1000 ° C., but the temperature of the outer end 8c when the cathode bright spot is formed in the central portion 8b is about 800 ° C. For this reason, when a cathode bright spot is formed in the central portion 8b, barium carbonate (BaCO ₃ ) supported on the outer end portion 8c is not decomposed and does not emit an impure gas. However, when a cathode bright spot is formed at the outer end 8c, the temperature of barium carbonate (BaCO ₃ ) rises to 1000 ° C. and is thermally decomposed into barium oxide (BaO). At this time, carbon dioxide gas is released in the discharge space due to thermal decomposition, and the lamp lighting voltage capable of maintaining the discharge rises and exceeds the allowable value of the output voltage of the lighting device, so that the discharge is stopped.

  Next, the lighting device according to the present embodiment will be described.

  FIG. 3 is a front view showing the lighting apparatus according to the present embodiment.

Illuminating device D shown in the figure is a ceiling-mounted lighting apparatus, and D1 in the figure is a main body of the lighting apparatus, which is attached to a structure (not shown) such as a ceiling surface and connected to a power source. A lighting device such as a mechanism and a ballast D2 is accommodated, and a pair of lamp sockets D3 and D3 are attached below the main body D1, and a fluorescent lamp 10 is mounted therebetween. The fluorescent lamp 10 is supported by the sockets D3 and D3, and is supplied with power through the ballast D2 and the sockets D3 and D3, so that it is lit stably.

  In addition, this invention is not limited to description content of said embodiment, A structure, a material, arrangement | positioning of each member, etc. can be suitably changed in the range which does not deviate from the summary of this invention.

It is the partially cutaway front view which showed the whole fluorescent lamp concerning this Embodiment. It is a principal part enlarged view which shows the electrode of FIG. It is a front view which shows the illuminating device which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Glass bulb, 7 ... Inner wells, 8 ... Filament, 8a ... Support part, 8b ... Center part, 8c ... Outer end part, 9 ... Electron radioactive substance, 10 ... Gas emission substance, D ... Illumination device.

Claims (2)

A translucent glass bulb;
A phosphor layer formed on the inner surface of the glass bulb;
A discharge medium enclosed in the glass bulb;
A pair of inner wells each introduced at an end in the glass bulb;
A support portion supported by each of the pair of inner wells; a center portion formed between the support portions; and an outer end portion projecting outward from the support portion. The center portion carries an electron-emitting material. And a filament carrying a gas releasing material for releasing gas by forming a cathode bright spot at the outer end portion;
A fluorescent lamp characterized by comprising: A fluorescent lamp according to claim 1;
A lighting device body to which the fluorescent lamp is attached;
A lighting device for lighting the fluorescent lamp;
An illumination device comprising:

Images