JPH0325852A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To obtain a fluorescent lamp which is of high luminance, as well as of little inhomogeneity in the luminance, with a relatively thin phosphor film, and for which leakage is not anticipated at the time of heat cycle by using a ceramic of a proper coefficient of thermal expansion, by which light is effectively reflected, for an airtight container main body. CONSTITUTION:In an airtight container main body 1, a partition 5 is integrated in a lattice, and six discharge spaces 6a, 6b, 6c, 7a, 7b, 7c are formed. The airtight container main body 1 is made of ceramic whose relative reflectance for 500nm is not less than 98 and not more than 100, when 600nm corresponds to 100, in a relative reflection spectrum using a reference sample of BaSO4 for this. A coefficient of thermal expansion of the airtight container main body 1 is to be restricted to the range 90X10<-7>-100X10<-7>/ deg.C. Leakage failure due to heat shock can thus be avoided to the best, and an emission spectrum of a phosphor can be reproduced accurately with high luminance with no inhomogeneity.

Description

[Detailed description of the invention] Industrial applications The present invention relates to fluorescent lamps.

2. Description of the Related Art An example of using a fluorescent lamp in a large color image display device has been proposed in Japanese Patent Application Laid-Open No. 61-55851. Apart from this, the applicant has previously proposed a fluorescent lamp as shown in FIG.

In this figure, discharge spaces 6a. 6b. 6c corresponds to one picture element, discharge spaces 7a, 7b . 7c each forms another picture element.

In Fig. 5, l' is the airtight container body, 2 is the front plate, and 3 is the airtight container body.
1 is a hole, 4 is an electrode filament storage part, 5 is a partition wall, 9 is an electrode filament, 10 is an internal lead-in wire, 11 is a stem, 1
2 is an exhaust pipe, 13 is an external lead-in line, 14a, 14b. 14
c, 15a. 15b and 15c are electrodes, and 16 is a substance having the functions of a getter and a mercury dispenser, respectively.

Problems to be Solved by the Invention In the configuration shown in FIG. 5, in order to make the airtight container body l' made of ceramic airtight, a front plate 2 made of glass, an electrode filament storage part 4, and six electrodes 1 are used.
4a. 14b, 14c, 15a, 15b. 15c must be hermetically sealed with low melting point glass or the like. Therefore, it is necessary to select a ceramic, glass, or low melting point glass with an appropriate coefficient of thermal expansion, and at the same time, use a ceramic that efficiently reflects the visible light emitted from the phosphor.

In order to efficiently reflect visible light, it is necessary to have a high reflectance over the entire wavelength range of visible light, and a so-called white ceramic is required. Furthermore, since low-cost soda glass is used for the front plate 2, a ceramic having a coefficient of thermal expansion comparable to that of soda glass is required.

The present invention was made in view of these circumstances.
The present invention provides a fluorescent lamp using ceramic that has an appropriate coefficient of thermal expansion and efficiently reflects visible light.

Means for Solving the Problem In order to solve this problem, the fluorescent lamp of the present invention uses B a S, which is commonly used as a standard sample for reflection spectra.
In the relative reflection spectrum for 04, 600n
When the relative repulsion coefficient of m is 1.00, the relative reflectance at 500 nm is 98 or more and 100 or less, the relative reflectance at 450 nm is 90 or more and hl00 or less, and the coefficient of thermal expansion is 90 n, 10-7,・'℃ or higher]. O O X
An airtight container is constructed from a ceramic airtight container body having a temperature of less than L O-7/'C, a front plate sealed to the airtight container body, and an electrode filament storage portion integrated into the bottom surface of the airtight container body. electrodes are provided at the ends of the airtight container body to form one or more discharge paths, and a fluorescent material is applied to the portion of the airtight container body that will become the discharge path.

Function When the fluorescent lamp of the present invention is used, for example, as a light emitting display device for a large color/image display device, since the ceramic is white, a reflective film such as titanium oxide is provided between the ceramic material and the phosphor. It is not necessary, and even a relatively thin phosphor film can provide high brightness with little n degree unevenness, and since the coefficient of thermal expansion is appropriate, there is no need to worry about leakage during heat cycles, and stable quality can be achieved. be able to.

EXAMPLES Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of a fluorescent lamp according to an embodiment of the present invention;
FIG. 2 shows a reflection spectrum diagram of the ceramic used for the airtight container body of the same fluorescent lamp, and FIG. 3 shows a relative reflection spectrum diagram when the relative reflectance at 600 nm is set to 100.

As shown in FIG. 1, the fluorescent lamp according to the embodiment of the present invention has a reflection spectrum as shown in each curve a in FIGS. 2 and 3, and a coefficient of thermal expansion of 97×10-7/°C. A rectangular airtight container body 1 made of a certain ceramic, a front plate 2 made of a glass plate sealed with low melting point glass, and a hole 3 made in the rear surface of the airtight container body 1, one end of which is sealed with low melting point glass. An airtight container is constituted by an electrode filament storage section 4 made of a glass tube whose other end is sealed. The reflection spectrum described here is generally called a diffuse reflection spectrum, and has a half-width of 10 nm.
Absorption spectra with the following steep peaks are not shown.

Therefore, in the range of 370 to 780 nm, 45
After determining the reflectance at three points of 0,500 and 600 nm,
Color of the substance 2'): Almost determined. The airtight container main body 1 of the embodiment has a standard sample of reflection spectrum/L at T3.
In the relative reflection spectrum when aSO4 is used,
When 600 nm is 100, the relative anti-At 28 of 500 nm is 98 or more and 100 or less. If it is less than 98, the reflection from blue to blue-green is insufficient and the decrease in brightness cannot be ignored; on the other hand, 1. If it exceeds 00, the relative anti-cutting rate of 600 ri rn will be low and the reflection of the red region will be insufficient.
The relative reflectance in nm should be 90 or more and 100 or more.

If it is less than 90, the reflection of blue light is insufficient and the reduction in the brightness of blue light cannot be ignored, while if it exceeds 100, it is 6
00nm. The relative reflectance at 500 nm is low, and reflection from blue to blue-green and red regions is insufficient. Furthermore, the coefficient of thermal expansion of the airtight container body is 90X.
less than 10'7/℃, and 100X ] O-7
If it exceeds /'C, the thermal expansion coefficient will be incompatible with the front plate 2, which is inexpensive and easily available soda glass, and the airtight container body 1 and front plate 2 will be destroyed during sealing or heat cycles. . Therefore, the thermal expansion coefficient of the airtight container body 1 is 90X10-7 to 100X10-7/'C
It is necessary to select within the range of .

Inside the airtight container body 1, partition walls 5 are integrally formed in a lattice shape, and six discharge spaces 6a, 6b, 6c,
7a, 7b. 7c is formed. At the center of the bottom of the airtight container body 1, that is, at one end of each discharge space,
As shown in FIG. 1, small holes 8 are provided independently, and these holes 8 communicate each discharge space with the space of the electrode filament housing 4. Near these holes 8, a coiled electrode filament 9 provided in the electrode filament housing 4 is connected to two internal lead-in wires 1.
It is supported and placed at 0. Two internal lead-in wires 10
is supported by a stem 11, and an external lead-in wire 1 is connected to these.
3 are connected to each other. Note that 12 indicates an exhaust pipe. Further, electrodes 14a, 14b, 1 are provided at the end far from the hole 8, that is, the other end of these discharge spaces.
4c, 15a + 15b + l5c are provided, and the electrode filament 9 and the electrodes 14a, 14b
, 14c. A plurality of discharge paths are formed between 15a, 15b, and 15c. The electrode filament 9 is provided in a direction in which its axis is orthogonal to the axes of the discharge spaces 6a, 6b, 6c, 7a, 7b, and 7c. Mercury and rare gas are sealed inside the airtight container.

A rare earth phosphor that emits green (G) light is placed on the ceramic walls forming the discharge paths of the airtight container body 1, that is, the discharge spaces 6a and 7a.
A rare earth phosphor that emits red (R) light is coated on the ceramic wall surface forming the discharge spaces 6c and 7c, and a rare earth phosphor that emits blue light (B) is coated on the ceramic wall surface forming the discharge spaces 6c and 7c. ing.

As described above, the discharge spaces 6a, 6b, and 6c form one picture element, and the discharge spaces 7a, 7b, and 7c form another picture element.

A current is passed through the electrode filament (cathode) 9 of such a light emitting element, and each electrode (anode) 14a, 14b, 14c,
By selecting and applying the voltage necessary for starting discharge to 1 5at 1 5bp 1 5c and changing the current flowing through each discharge path, it was possible to obtain chromaticity within the range shown in Figure 4. . Furthermore, it was also observed that when these currents were changed over time, the brightness changed to follow the changes. Such a result means that this light emitting device can be used for displaying color images.

According to this precept, the conventionally used material has the reflection spectrum shown in each curve b in Figs. 2 and 3 and has a coefficient of thermal expansion of 98 x 10-7/°C. The same level of brightness can be obtained with 20% less phosphor coating than when using a ceramic called Holsterite. This not only reduces cost, but also prevents the film from peeling off due to thick coating of the phosphor. Furthermore, since absorption in the blue region is lower than in conventional examples, the emission spectrum of the blue phosphor can be faithfully reproduced. Note that the reflection spectrum shown by curve C in FIG. 2 is a ceramic called steatite. Although it has very good reflective properties, it does not have an appropriate coefficient of thermal expansion and is prone to leakage due to heat shock.

Effects of the Invention As explained above, the present invention can avoid leak defects caused by heat shock as much as possible, and
It is possible to provide a fluorescent lamp with high brightness, little unevenness in brightness, and capable of faithfully reproducing the emission spectrum of a phosphor.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a fluorescent lamp that is an embodiment of the present invention, and FIG. 2 is a diagram showing the reflection spectra of the ceramic used in the fluorescent lamp and other typical ceramics.
Fig. 3 is a diagram showing the relative reflection spectrum when 600 nm is set as 100, Fig. 4 is a chromaticity diagram showing the emission color range of the fluorescent lamp according to the present invention, and Fig. 5 is a diagram showing the emission color range of the fluorescent lamp according to the present invention. FIG. 2 is an exploded perspective view of a fluorescent lamp. 1... Airtight container body, 2... Front plate,
3... Hole, 4... Electrode filament housing section, 5... Partition wall, 6a. 6b. 6c, 7a,
7b, 7c--Discharge space, 8... Hole, 9...
... Electrode filament, 14a, 14b, 14c,
15a, 15b, 15c...electrodes.

Claims (1)

[Claims] In the relative reflection spectrum for BaSO_4,
When the relative reflectance at 600nm is 100, 500n
The relative reflectance of m is 98 or more and 100 or less, the relative reflectance of 450 nm is 90 or more and 100 or less, and the thermal expansion coefficient is 90 x 10^-^7/℃ or more 100 x 10^-^7
An airtight container is formed from a ceramic airtight container main body having a temperature of /°C or less, a front plate sealed to the airtight container main body, and an electrode filament accommodating portion integrated into the bottom surface of the airtight container main body, and the airtight container is A fluorescent lamp characterized in that an electrode is provided at an end of the container body to form one or more discharge paths, and a portion of the airtight container body that becomes the discharge path is coated with a phosphor.