JPH09147808A - Electrodeless fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrodeless fluorescent lamp which can improve luminous efficiency without replacing phosphor. SOLUTION: A layer of three wavelength rare earth phosphor 3 is formed in an inner wall of the outer tube 1, and tens of milligram of mercury and several Torrs of argon gas are sealed in a gas-tight vessel 5 so as to serve as discharge gas. A layer of the three wavelength rare earth phosphor 3 is formed on the outer wall of the inner tube 2 having a structure of a concentric double tube, and an induction coil 4 into which a high frequency current flows is provided inside the inner tube 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airtight container having ultraviolet rays generated by discharge by applying a high-frequency electromagnetic field from the outside to a discharge gas sealed inside without having an electrode inside the airtight container. The present invention relates to an electrodeless fluorescent lamp adapted to excite and emit a phosphor coated on the inner wall of the.

[0002]

2. Description of the Related Art Conventionally, a high-frequency current is applied to an induction coil wound inside an inner tube of an airtight container so that a high-frequency electromagnetic field generated around the induction coil is enclosed in the airtight container. There is known an electrodeless fluorescent lamp in which a so-called electrodeless discharge is generated in an airtight container to excite and ionize a luminescent substance to emit light.

FIG. 4 shows such a conventional electrodeless fluorescent lamp, in which discharge gas is enclosed in the airtight container 5, and the inner wall surface and inner tube of the outer tube 1 of the airtight container 5 are sealed. A phosphor 3 is applied to the outer wall surface of 2, and an induction coil 4 is provided inside the inner tube 2 of the airtight container 5.
In the electrodeless fluorescent lamp having such a configuration, the induction coil 4
When a high-frequency current is passed through, a high-frequency electromagnetic field is generated by the current, and the magnetic field forms a solenoid electric field inside the airtight container 5 which is perpendicular to the magnetic field and is completely closed. A current flows due to this electric field, a donut-shaped discharge is generated in the airtight container 5, and ultraviolet rays are emitted, and the ultraviolet rays excite the phosphor 3 applied to the inner wall of the airtight container 5 to emit light.

As a similar conventional example, an actual Kaihei 7-14599
No. and Jitsukaihei 7-14549,
In these conventional examples, the exhaust pipe is provided so as to pass through the center of the inner pipe, but basically the same operation as the conventional example of FIG. 4 is performed.

[0005]

By the way, in the conventional electrodeless fluorescent lamp configured as described above, in order to improve the luminous efficiency, it is necessary to change the type of the fluorescent substance 3 and the induction coil 4 inside. To be placed inside the tube 2,
The heat generated from the induction coil 4 causes a high temperature inside the inner tube 2 and shortens the life of the lamp.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrodeless fluorescent lamp which can improve the luminous efficiency without changing the phosphor.

[0007]

In order to achieve the above object, in the invention of claim 1, an outer tube having an inner wall surface coated with a phosphor and an outer tube formed at a substantially central portion of the outer tube are provided. A translucent airtight container that is composed of an inner tube whose surface is coated with a phosphor and has a discharge gas sealed inside, and from the outside of the airtight container that is wound inside the inner tube of the airtight container. In an electrodeless fluorescent lamp comprising an induction coil for exciting and discharging the discharge gas by applying a high-frequency electromagnetic field, the inner tube of the airtight container has a concentric double tube structure, and the induction coil is a double tube. It is characterized by being placed in the structure, because the inner tube of the airtight container has a concentric double structure, the surface area coated with the phosphor spreads, thereby increasing the utilization efficiency of ultraviolet rays generated by discharge, As a result, the luminous efficiency can be easily improved. Rukoto can.

Further, in the invention according to claim 2, in the electrodeless fluorescent lamp according to claim 1, the central part of the outer tube has a double tube structure which is convex inward, and the outer tube convex part is formed. It is characterized in that it is placed inside the recess of the double tube structure of the inner tube, and by applying a double tube structure in which the central part of the outer tube is convex inward, the coating area of the phosphor is widened, which results in discharge. The utilization efficiency of the ultraviolet rays generated by the above increases, and as a result, the luminous efficiency can be easily improved, and the heat generated by the induction coil can be dissipated to lower the temperature inside the inner tube.

Further, in the invention of claim 3, the electrodeless fluorescent lamp according to claim 1 is characterized in that the side peripheral surface of the inner tube has a concave-convex structure. Since the peripheral surface is formed to be uneven, the coating area of the phosphor can be further widened, and as a result, the utilization efficiency of ultraviolet rays generated by discharge can be increased and the luminous efficiency can be further improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

 (First Embodiment) FIG. 1 shows the first embodiment.
This electrodeless fluorescent lamp has a substantially spherical outer tube 1 and
The inner tube 2 is integrally formed in the center of the outer tube 1.
A structure provided with an airtight container 5, a phosphor 3 and an induction coil 4.
The outer tube 1 of the airtight container 5 made of a material has a light-transmitting property.
It is not particularly limited as long as it does, for example,
It is made of soda-lime glass and has a firefly on its inner wall.
Three-wavelength rare-earth phosphor 3 (for example, red: Y_Two
O_Three: Eu, green: LaPO _Four: Tb, blue: (SrC
aBa)_Five(PO_Four)_ThreeCl: Eu) layer is formed
I have. Then, inside the airtight container 5 having airtightness,
As an electric gas, for example, several tens of mg of mercury and several Torr of
Gongas is enclosed. Also, inside the inner tube 2,
An induction coil 4 through which a frequency current is passed is provided, and further,
A lamp is fixed to the lower part which is one end side of the airtight container 5.
A cap (not shown) is provided for this. 6 in the figure
It is a chip part.

The inner tube 2 is made of, for example, soda-lime glass, like the outer tube 1, and has a concentric double tube structure, and the outer wall surface has a three-wavelength rare earth phosphor 3 which is a phosphor. (For example, red: Y ₂ O ₃ : Eu, green: LaP
O ₄ : Tb, Blue: (SrCaBa) ₅ (PO ₄ ) ₃ C
l: Eu) is formed. In the electrodeless fluorescent lamp of the present embodiment configured as described above, the inner tube 2
The surface area for applying the phosphor is increased by the double structure, thereby increasing the utilization efficiency of ultraviolet rays generated by the discharge, and as a result, improving the luminous efficiency.

(Embodiment 2) FIG. 2 shows this embodiment. The difference from Embodiment 1 is that the airtight container 5 is
It is different in that the central portion of the outer tube 1 is formed in a double tube structure that is convex inward, and the rest is configured similarly to the first embodiment. The outer tube 1 of the airtight container 5 has a double tube structure in which the central portion is convex inward, and the outer tube convex portion 1a is arranged inside the concave portion 2a of the double tube structure of the inner tube 2, and at least the inner surface is Similar to the first embodiment, a layer of the three-wavelength rare earth phosphor 3 which is a phosphor is formed.

In the electrodeless fluorescent lamp according to the present embodiment having the above-described structure, the surface area of the luminous body 3 coated is expanded by the convex portion 1a of the outer tube, so that the utilization efficiency of ultraviolet rays generated by the discharge is increased. The luminous efficiency can be easily improved. Further, there is an effect that the heat generated by the induction coil 4 is dissipated and the temperature inside the inner pipe can be lowered.

(Embodiment 3) FIG. 3 shows the present embodiment, which is different from Embodiment 1 in that a convex-concave portion 7 is formed on the side surface of the patience inner tube 2. Is configured similarly to the first embodiment. In the electrodeless fluorescent lamp of the present embodiment configured as described above, the phosphor 3
The surface area applied to the surface of the inner tube 2 expands by the amount corresponding to the projections and depressions 7 on the side surface of the inner tube 2, the efficiency of utilizing ultraviolet rays generated by the discharge increases, and the luminous efficiency can be easily improved.

[0015]

According to the first aspect of the present invention, there is provided an outer tube having an inner wall surface coated with a phosphor and an inner tube having a substantially central portion of the outer tube having an outer wall surface coated with the phosphor. A light-tight airtight container having a discharge gas sealed inside, and an induction for exciting the discharge gas by causing a high-frequency electromagnetic field to act from the outside of the airtight container while being wound inside the inner tube of the airtight container. In an electrodeless fluorescent lamp comprising a coil, the inner tube of the airtight container has a concentric double tube structure, and the induction coil is arranged in the double tube structure, so that the surface area coated with the phosphor is As a result, the utilization efficiency of the ultraviolet rays generated by the discharge is increased, and as a result, the luminous efficiency can be easily improved without changing the phosphor.

According to a second aspect of the present invention, in the electrodeless fluorescent lamp according to the first aspect, the central portion of the outer tube has a double tube structure in which the inner tube is convex, and the outer tube projection is of the inner tube. Since it is placed inside the recess of the double tube structure, the coating area of the phosphor is expanded, the utilization efficiency of the ultraviolet rays generated by the discharge is increased, and as a result, the luminous efficiency can be easily improved without changing the phosphor. Moreover, there is an effect that the heat generated by the induction coil can be dissipated and the temperature inside the inner pipe can be lowered.

Further, according to the invention of claim 3, in the electrodeless fluorescent lamp according to claim 1, since the side peripheral surface of the inner tube has an uneven structure, the coating area of the phosphor can be further expanded. Therefore, the efficiency of utilizing ultraviolet light generated by the discharge is further increased, and as a result, the luminous efficiency can be easily improved without changing the phosphor.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a first embodiment of the present invention.

FIG. 2 is a front sectional view of Embodiment 2 of the present invention.

FIG. 3 is a front cross-sectional view of Embodiment 3 of the present invention.

FIG. 4 is a front sectional view of a conventional example.

[Explanation of symbols]

 1 Outer tube 2 Inner tube 3 Phosphor 4 Induction coil 5 Airtight container

Claims (3)

[Claims] 1. An outer tube having an inner wall coated with a phosphor, and an inner tube having a substantially central portion of the outer tube having a outer wall coated with the phosphor, the discharge gas being sealed inside. In an electrodeless fluorescent lamp comprising an airtight container having a light-transmitting property, and an induction coil which is wound inside the inner tube and causes a high-frequency electromagnetic field to act from the outside of the airtight container to excite the discharge gas to emit light. An electrodeless fluorescent lamp characterized in that the inner tube of the airtight container has a concentric double tube structure and the induction coil is arranged in the double tube structure. 2. The double pipe structure in which the central portion of the outer pipe is convex inward, and the convex portion of the outer pipe is arranged inside the concave portion of the double pipe structure of the inner pipe. Electrodeless fluorescent lamp. 3. The electrodeless fluorescent lamp according to claim 1, wherein the side peripheral surface of the inner tube has an uneven structure.