JPH08129988A - Fluorescent lamp - Google Patents

Abstract

PURPOSE: To improve a light flux maintaining rate of a lamp without deteriorating light emitting efficiency and light color characteristics (chromaticity and a color rendering property) as well as to reduce cost. CONSTITUTION: In a fluorescent lamp which is provided with a light transmissive airtight vessel 1 in which a phosphor coating film 3 is formed on an inner wall 1a and inside which discharge gas is sealed and emits visible radiation outside of the airtight vessel 1 by converting ultraviolet rays generated by discharge into the visible radiation by the phosphor coating film 3, the phosphor coating film 3 is formed by applying at least two kinds of phosphors, whose compositions are different from each other and light emitting spectral distribution shapes are almost the same, in a multilayer shape, and the phosphor of which the degradation characteristic is relatively more superior is applied to a layer as the layer is situated closer to the discharge side 4 in the airtight vessel 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a phosphor coating on the inner wall of an airtight container filled with a discharge gas, converts ultraviolet rays generated by discharge into visible light by the phosphor coating, and converts the visible light into an airtight container. The present invention relates to a fluorescent lamp that emits to the outside.

[0002]

2. Description of the Related Art Fluorescent lamps are one of the important and widely used light sources today. FIG. 2 shows a fluorescent lamp having an electrode, which is one of such conventional fluorescent lamps. The fluorescent lamp has a transparent and airtight glass bulb 1 at both ends. A filament 2 which is an electrode is provided, and mercury is enclosed together with argon gas in the glass bulb 1. A plurality of phosphors having different emission spectrum distribution shapes are mixed and applied to the inner wall 1a of the glass bulb 1. Thus, the phosphor coating 3 is formed. Then, the ultraviolet rays generated by the discharge of the mercury are converted into visible light by the phosphor coated on the inner wall 1a, and the visible light is utilized.

On the other hand, in recent years, environmental problems have become more important, and mercury enclosed in a fluorescent lamp is also discarded as the fluorescent lamp reaches the end of its life. For this reason, many efforts have been made to reduce or eliminate mercury in fluorescent lamps. As a candidate for an ultraviolet ray radiation source to replace mercury, for example, a rare gas fluorescent lamp using ultraviolet rays (wavelength 147 nm) from a xenon discharge is also available.
Although it is inferior to the one using mercury in efficiency, it is being put to practical use in some applications.

[0004]

By the way, the phosphor, which is an important material for such a fluorescent lamp, has good luminous efficiency and has a desired emission spectrum distribution (chromaticity, color rendering), Various characteristics such as excellent deterioration characteristics and low cost are required, and generally, a phosphor to be used is selected in consideration of these characteristics.
Therefore, although there is room for selection of phosphor materials with similar emission efficiency and emission spectrum distribution, there are often large differences in deterioration characteristics and costs between them, and it is not possible to fully utilize these phosphor materials. However, there has been a problem that the luminous flux maintenance factor of the fluorescent lamp may become low or the cost may become high.

The present invention has been made to solve the above problems, and an object of the present invention is to achieve a high luminous flux maintenance rate without lowering luminous efficiency and light color characteristics (chromaticity and color rendering). , To provide a low cost fluorescent lamp.

[0006]

In order to solve the above-mentioned problems, the present invention provides a light-permeable hermetic container 1 in which the phosphor coating 3 is provided on the inner wall 1a. A discharge gas is sealed inside, and ultraviolet rays generated by the discharge are converted into visible light by the phosphor coating 3.
In the fluorescent lamp that emits the visible light to the outside of the hermetic container 1, the phosphor coating 3 is formed by including at least two kinds of phosphors having different compositions and substantially the same emission spectrum distribution shapes. To do.

According to a second aspect of the invention, in the fluorescent lamp according to the first aspect, the phosphor coating 3
Among the at least two types of phosphors having different composition and substantially the same emission spectrum distribution shape, the content ratio of the phosphors having relatively excellent deterioration characteristics is set to the discharge side 4 in the airtight container 1. The feature is that the height is increased toward the closer side.

Further, in the invention according to claim 3, in the fluorescent lamp according to claim 1 or 2, the phosphor coating 3 has the different composition and the emission spectrum distribution shape is substantially the same. It is characterized in that at least two types of phosphors are formed in multiple layers and that the closer to the discharge side 4 in the hermetic container 1, the higher the content ratio of the phosphors having relatively excellent deterioration characteristics. To do.

Further, in the invention according to claim 4, in the fluorescent lamp according to claim 1 or 2,
The phosphor coating 3 is formed by applying at least two kinds of phosphors having different compositions and having substantially the same emission spectrum distribution shape in multiple layers, and is also a layer close to the discharge side 4 in the airtight container 1. This is characterized in that a phosphor having relatively excellent deterioration characteristics is applied.

[0010]

As described above, according to the present invention, the phosphor coating 3 is provided on the inner wall 1a, and the discharge gas is filled in the light-tight airtight container 1. In the fluorescent lamp that converts the ultraviolet rays generated by the discharge into visible light by the phosphor coating 3 and emits the visible light to the outside of the airtight container 1, the phosphor coating 3 has a different composition. Since it is formed by including at least two kinds of phosphors having substantially the same emission spectrum distribution shape,
The cost and deterioration characteristics of the phosphor change depending on the mixture ratio, and it is possible to balance the reduction of cost and the improvement of the luminous flux maintenance factor by the improvement of the deterioration characteristics.

According to a second aspect of the invention, in the fluorescent lamp according to the first aspect, the phosphor coating 3
Among the at least two types of phosphors having different composition and substantially the same emission spectrum distribution shape, the content ratio of the phosphors having relatively excellent deterioration characteristics is set to the discharge side 4 in the airtight container 1. Since the height is increased toward the side closer to the discharge side, the discharge side 4 on which the phosphor easily deteriorates due to ion bombardment or the like is coated with a large amount of the phosphor excellent in deterioration characteristics, and the inner side 1a side of the airtight container 1 which is the lower side thereof is applied. Even if a large amount of a fluorescent substance that easily deteriorates is applied and applied, the deterioration is suppressed by the fluorescent substance applied to the discharge side 4, and the decrease in the luminous flux maintenance factor is reduced.

Further, in the invention according to claim 3, in the fluorescent lamp according to claim 1 or 2, the phosphor coating 3 has the different composition and has substantially the same emission spectrum distribution shape. A layer containing at least two kinds of phosphors is formed in multiple layers, and the closer to the discharge side 4 in the hermetic container 1, the higher the content ratio of the phosphors having relatively excellent deterioration characteristics. Due to the fact that a large amount of a phosphor having excellent deterioration characteristics is applied to the layer 3a on the discharge side 4 where the phosphor easily deteriorates, the layer 3b on the inner wall 1a side of the airtight container 1 below the layer 3a deteriorates. Even if a large amount of easy-to-use phosphor is contained and applied, the deterioration is suppressed by the phosphor applied to the discharge side 4, and the decrease in luminous flux maintenance factor is reduced.

Further, in the invention according to claim 4, in the fluorescent lamp according to claim 1 or 2,
The phosphor coating 3 is formed by applying at least two kinds of phosphors having different compositions and having substantially the same emission spectrum distribution shape in multiple layers, and is also a layer close to the discharge side 4 in the airtight container 1. Since the phosphor having relatively excellent deterioration characteristics is applied, the phosphor 3 having excellent deterioration characteristics is applied to the layer 3a on the discharge side 4 where the phosphor is easily deteriorated by ion bombardment or the like. The inner wall 1 of the airtight container 1 which is
Even if a phosphor that easily deteriorates is applied to the a-side layer 3b, the deterioration is suppressed by the phosphor applied to the discharge side 4, and the decrease in the luminous flux maintenance factor is reduced.

[0014]

FIG. 1 shows a first embodiment of the fluorescent lamp of the present invention. This fluorescent lamp has electrodes at both ends in a glass bulb 1 which is an airtight container having a light-transmitting property. A filament is provided, and mercury is enclosed in the glass bulb 1 together with argon gas.
A is coated with a phosphor to form a phosphor coating 3 on the surface a. Then, the ultraviolet light generated by the discharge of the mercury is converted into visible light by the phosphor coated on the inner wall 1a, and the visible light is utilized.

The phosphor coating 3 is made of two kinds of phosphors having different compositions and substantially the same emission spectrum distribution shape.
It is formed by coating the layers. That is, on the discharge side 4 of the inner wall 1a of the airtight container 1, europium-activated barium
The magnesium-aluminate phosphor is applied as the first phosphor A, for example, 3 mg / cm ² to form the layer 3 on the discharge side 4.
a is formed and on the inner wall 1a side of the airtight container 1 which is the lower side thereof, the second phosphor B is a europium-activated strontium halophosphate phosphor, a europium-activated strontium calcium halophosphate. One kind of phosphor selected from the group consisting of a salt phosphor and a europium-activated strontium-calcium-barium-halophosphate phosphor is applied, for example, at 10 mg / cm ² to the inner wall 1a side of the airtight container 1. It is referred to as layer 3b.

Since the fluorescent lamp of this embodiment is constructed in this manner, the two types of phosphors have substantially the same emission spectrum distribution, so that their light color characteristics (chromaticity, color rendering), etc. Even if the phosphor A having excellent deterioration characteristics is applied to the layer 3a on the discharge side 4 where the phosphor easily deteriorates due to ion bombardment or the like, the layer 3b on the inner wall 1a side of the airtight container 1, which is the lower side of the layer 3b. Even if the phosphor B that is easily deteriorated is applied, the deterioration is suppressed by the phosphor A that is applied to the discharge side 4 and is resistant to deterioration, and the decrease in the luminous flux maintenance factor is reduced. Further, the phosphor A, which is resistant to deterioration and is applied to the discharge side 4, can completely cover the phosphor B on the lower side, which is easily deteriorated, even if the amount is relatively small, and a sufficient effect can be obtained and the phosphor easily deteriorates. Phosphor B
As a result, if a low cost phosphor is used, it is possible to obtain the deterioration characteristics of the phosphor coating 3 which is almost comparable to the phosphor A alone, and it is possible to significantly reduce the cost of the fluorescent lamp. In particular, in the case where the phosphor A has excellent deterioration characteristics but is expensive, the inexpensive phosphor is coated on the lower side of the phosphor A, and the phosphor A is coated on the phosphor. Significant cost reduction can be achieved while drawing out deterioration characteristics. Further, since different phosphors are applied to the respective layers, it is possible to easily select those having different deterioration characteristics and different costs for each layer, and it is easy to manufacture.

FIG. 2 shows a second embodiment of the fluorescent lamp according to the present invention, which is different from the first embodiment in the phosphor coating 3, and the others are the same as in the first embodiment. It is similarly configured.

The phosphor coating 3 is formed in two layers including the phosphor A which is resistant to deterioration of the first embodiment and the phosphor B which is relatively inferior in deterioration characteristics, but the layer 3a on the discharge side is formed. And the layer 3b on the inner wall side are both coated with a phosphor mixed with the two types of phosphors. In the layer 3a on the discharge side, a mixed phosphor having a high content ratio of the phosphor A resistant to deterioration is Inner wall layer 3b
In the above, a mixed phosphor having a high content of phosphor B, which is relatively inferior in deterioration characteristics, is applied.

Since the fluorescent lamp of this embodiment is constructed in this manner, the two types of fluorescent materials have substantially the same emission spectrum distribution, so that their light color characteristics (chromaticity, color rendering), etc. The same applies to the layer 3a on the discharge side 4 where the phosphor easily deteriorates due to ion bombardment or the like, the mixed phosphor having a high content ratio of the phosphor A having excellent deterioration characteristics is applied, and the airtight container 1 underneath it is coated. By applying the mixed phosphor having a high content ratio of the phosphor B, which easily deteriorates, to the layer 3b on the inner wall 1a side, the deterioration property is greatly influenced by the deterioration property of the phosphor A in accordance with the content ratio, and the discharge side The layer 3a of No. 4 largely contributes to the deterioration characteristics of the phosphor coating 3, the deterioration of the phosphor coating 3 is improved more than the case where only the phosphor B is used, and the luminous flux maintenance factor is improved. In addition, if a low-cost phosphor is used as the phosphor B that easily deteriorates, the cost of the fluorescent lamp can be reduced. In particular, when the phosphor A has excellent deterioration characteristics but high cost, Significant cost reduction can be achieved while bringing out the excellent deterioration characteristics of the body A. Furthermore, since each layer is formed by mixing a plurality of phosphors, the cost and deterioration characteristics of the phosphors in each layer can be set relatively freely by changing the mixing ratio and the like.

FIGS. 3 and 4 show a third embodiment of the fluorescent lamp of the present invention, which is different from the second embodiment in the phosphor coating 3 and the other is in the second embodiment. The configuration is similar to that of the embodiment.

The phosphor coating 3 is formed by mixing two kinds of phosphors having different compositions and substantially the same emission spectrum distribution shape and coating them in one layer. For example, the phosphor coating 3 is resistant to deterioration in the first embodiment. The phosphor A has a small particle size, and the phosphor B having relatively poor deterioration characteristics is mixed with a large particle size, and the mixed phosphor is applied to the inner wall 1a of the airtight container 1 to form particles. The phosphor B having a large diameter is biased toward the inner wall 1a of the airtight container 1 which is the lower side so that the content of the phosphor A is high on the discharge side 4 and the content of the phosphor B is large on the inner wall 1a side of the airtight container 1. It is designed to be high.

Due to this structure, in the fluorescent lamp according to the present embodiment, as shown in FIG. 4, the phosphor B having a large particle size is biased toward the inner wall 1a side of the hermetic container 1 and the hermetic container 1 The content rate of the phosphor B is increased on the inner wall 1a side, and the content rate of the phosphor A having a small particle size is increased on the discharge side 4, which is substantially the same as that of the second embodiment. Play.

FIG. 5 and FIG. 6 show a fourth embodiment of the fluorescent lamp of the present invention, the difference from the third embodiment is the phosphor coating 3, and the other is the third embodiment. The configuration is similar to that of the embodiment.

The phosphor coating 3 comprises cerium / terbium co-activated lanthanum / phosphate phosphor, cerium / terbium co-activated magnesium / aluminate phosphor, cerium / terium.
A phosphor mixed with at least two kinds of phosphors selected from the group consisting of a terbium co-activated yttrium / silicate phosphor and a cerium / terbium co-activated gadolinium / magnesium / borate phosphor. ing.

Since the fluorescent lamp of the present embodiment is constructed in this way, the cost and deterioration characteristics of the mixed fluorescent material can be reduced by selecting the mixed fluorescent material.
It changes according to the characteristics and mixing ratio of each before mixing, and becomes an intermediate level between the characteristics of each before mixing, and it is possible to balance cost reduction and improvement of the luminous flux maintenance factor. The lamp cost can be reduced and the luminous flux maintenance ratio can be improved in proportion to the ratio.

In the fourth embodiment, the phosphor A has a relatively excellent deterioration characteristic and the phosphor B has an inferior deterioration characteristic.
As the fluorescent lamp, a fluorescent lamp having the same structure as that of the first to third embodiments may be used. Further, in the first and second embodiments, the phosphor coating 3 has two layers, and the emission spectrum of the phosphor is the same. However, the present invention is not limited to this, and the present invention is not limited to this, and a multi-layer structure such as three layers or four layers, or three or more types of phosphors. It may be like using the body.

Further, in each of the above embodiments, the fluorescent lamp has been described as a straight tube type fluorescent lamp having electrodes, but the present invention is not limited to this, and a round fluorescent lamp, It may be any fluorescent lamp such as a so-called compact lamp and an electrodeless fluorescent lamp which is a lamp having no electrode inside.

[0028]

Since the present invention has the above-mentioned structure, in the invention described in claim 1, since the plurality of phosphors have substantially the same emission spectrum distribution, their light color characteristics (chromaticity, chromaticity,
The color rendering property) does not change, and the cost and deterioration characteristics of the phosphor are
Depending on the characteristics of the phosphor used and its mixture ratio, it is possible to balance the cost reduction and the improvement of the luminous flux maintenance rate by improving the deterioration characteristics, and reduce the lamp cost commensurate with the mixture ratio. And the luminous flux maintenance factor can be improved.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, a phosphor excellent in deterioration characteristics is provided on the discharge side where the phosphor is easily deteriorated by ion bombardment or the like. By coating with a large content, even if it is coated with a large amount of phosphor that easily deteriorates on the inner wall side of the airtight container that is the lower side, the deterioration is suppressed by the phosphor coated on the discharge side. In addition, the decrease in the luminous flux maintenance factor is reduced, and it is possible to use a low-cost phosphor, which can reduce the cost of the lamp.

Further, in the invention of claim 3, in addition to the effect of claim 1 or claim 2, the layer on the inner wall side of the hermetic container is coated with a large amount of easily deteriorated phosphor. Even so, the deterioration is suppressed by the phosphor applied to the discharge side, the decrease in the luminous flux maintenance factor is reduced, and the inexpensive phosphor can be used, and the cost of the lamp can be reduced.

Further, in the invention of claim 4, in addition to the effect of claim 1 or claim 2, the deterioration characteristics of the layer on the discharge side where the phosphor easily deteriorates due to ion bombardment or the like. By applying an excellent phosphor, even if a phosphor that is prone to deterioration is applied to the inner wall side layer of the airtight container that is the lower side, the deterioration is suppressed by the phosphor applied to the discharge side. In addition, the reduction of the luminous flux maintenance rate is reduced, and it becomes possible to use a low cost phosphor, the cost of the lamp can be reduced, and the discharge side, which is the surface of the phosphor coating, is made a phosphor with excellent deterioration characteristics. Easy to manufacture lamps.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of an airtight container coated with a phosphor according to a first embodiment of a fluorescent lamp of the present invention.

FIG. 2 is a sectional view of an essential part of an airtight container coated with a phosphor according to a second embodiment of the fluorescent lamp of the present invention.

FIG. 3 is a sectional view of a main part of an airtight container coated with a phosphor according to a third embodiment of the fluorescent lamp of the present invention.

FIG. 4 is a graph showing the relationship of the content ratio of each phosphor in the thickness direction of the phosphor coating.

FIG. 5 is a cross-sectional view of a main part of an airtight container coated with a phosphor according to a fourth embodiment of the fluorescent lamp of the present invention.

FIG. 6 is a graph showing deterioration characteristics of each phosphor described above.

FIG. 7 is a front view of a partial cross section of a main part showing a conventional fluorescent lamp.

[Explanation of symbols]

 1 Airtight container 1a Inner wall 3 Phosphor coating 3a Discharge side layer 3b Inner wall side layer 4 Discharge side A Phosphor with excellent deterioration characteristics B Phosphor with poor deterioration characteristics

Claims (4)

[Claims] 1. A phosphor coating is provided on the inner wall,
In a fluorescent lamp in which a discharge gas is enclosed in an airtight container having a light-transmitting property, ultraviolet rays generated by discharge are converted into visible light by the phosphor coating, and the visible light is emitted to the outside of the airtight container. A fluorescent lamp, wherein the phosphor coating is formed by including at least two kinds of phosphors having different compositions and substantially the same emission spectrum distribution shape. 2. The phosphor coating has a content ratio of phosphors having relatively excellent deterioration characteristics among at least two kinds of phosphors having different compositions and substantially the same emission spectrum distribution shape, 2. The fluorescent lamp according to claim 1, wherein the height is increased as it is closer to the discharge side in the airtight container. 3. The phosphor coating is formed in multiple layers including at least two types of phosphors having different compositions and substantially the same emission spectrum distribution shape, and is close to the discharge side in the airtight container. The layer has a higher content of a phosphor having relatively excellent deterioration characteristics.
Alternatively, the fluorescent lamp according to claim 2. 4. The phosphor coating is formed by applying at least two kinds of phosphors having different compositions and having substantially the same emission spectrum distribution shape in a multilayer structure, and is close to the discharge side in the airtight container. The fluorescent lamp according to claim 1 or 2, characterized in that a phosphor having a relatively excellent deterioration characteristic is applied to the layer.