JPH097545A - Fluorescent lamp - Google Patents

Abstract

PURPOSE: To improve luminous efficiency, and/or reduce a lamp cost. CONSTITUTION: A reflecting layer 2, composed of magnesium oxide having a mean particle diameter of 0.5-5.0μm, is formed in the inner surface of a glass bulb 1. The adhering quantity of the layer 2 is set in a range of 0.1-3.2mg/cm<2> . A luminous layer 3 is overlappedly formed onto the layer 2. The layer 3 is constituted of, e.g. an active germanium fluoride acid magnesium phosphor with manganese.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp, and more particularly to improvement of a red fluorescent lamp suitable for an optical character reader (OCR).

[0002]

2. Description of the Related Art A conventional fluorescent lamp of this type is constructed, for example, by forming a light emitting layer made of manganese activated magnesium fluorogermanate phosphor having a light emitting peak at 658 nm on the inner surface of a glass bulb.

According to this fluorescent lamp, its light emitting peak
Since the darkness is in the deep red region (658 nm), the OCR reading accuracy can be improved.

[0004]

However, although the above-mentioned magnesium fluorogermanate phosphor is practically used and used in this fluorescent lamp, it is used in general white fluorescent lamps and daylight fluorescent lamps. The price is 42,000 yen / kg, which is extremely expensive compared to the price of the existing calcium halophosphate phosphor (800 yen / kg). Therefore, there is a problem that the cost of the fluorescent lamp becomes high.

Moreover, its luminous efficiency is 15 L, compared with 83 Lm / W of the calcium halophosphate phosphor.
There is also a problem of extremely low m / W, and there is a demand for cost reduction and improvement of luminous efficiency.

[0006] Therefore, the present inventor thinks that the luminous efficiency can be improved by increasing the utilization rate of ultraviolet rays, and titanium oxide (TiO ₂ ) is provided between the glass bulb and the light emitting layer (magnesium fluorogermanate phosphor). ), Alumina (Al ₂ O ₃ ), and magnesium oxide (MgO) are used to fabricate a fluorescent lamp, and the radiant intensity (light output) is measured. As a result, only the fluorescent lamp using magnesium oxide is titanium oxide. The result is that the emission intensity is higher than that of a fluorescent lamp using alumina.

In order to investigate this phenomenon, a clear lamp without a reflecting layer and a light emitting layer formed on a glass bulb, an AL lamp having only a reflecting layer made of alumina, and an MG lamp having only a reflecting layer made of magnesium oxide are used. When manufactured, and the radiation intensity of the mercury line in the short wavelength region of visible light was measured, the results shown in Table 1 were obtained.

[0008]

[Table 1]

As is clear from these results, in the AL lamp, the radiant intensity is all lower than that of the clear lamp in the mercury line of 405, 435, 545 nm, whereas it is increased in the MG lamp. .

At this point, when the spectral reflectance of magnesium oxide was measured, the results shown in FIG. 3 were obtained. this is,
Although it is shown as a comparative relative value with the reflectance by barium sulfate being 100, it was confirmed that the reflectance increased in the region of approximately 340 to 500 nm, which matches the results in Table 1.

The present inventor, based on the above experimental results,
When the change in radiation intensity depending on the amount of magnesium oxide deposited was examined, the results shown in Table 2 were obtained. In addition, a magnesium fluoride germanate phosphor was used for the light emitting layer.

[0012]

[Table 2]

As is clear from this result, the fluorescent lamp having the reflective layer made of magnesium oxide has an increased radiation intensity at 658 nm in the deep red region as compared with the fluorescent lamp having no reflective layer. It suggests that the luminous efficiency can be improved according to the amount of the adhered substance. The radiation intensity of the mercury lines 405, 435, 545 nm decreases conversely as the deposition amount of magnesium oxide increases. It is speculated that this is because these mercury lines are absorbed by the light emitting layer and used for excitation.

Therefore, it is an object of the present invention to provide a fluorescent lamp which can improve the luminous efficiency or reduce the lamp cost based on the above findings.

[0015]

Therefore, in order to achieve the above-mentioned object, the present invention provides a reflective layer made of magnesium oxide formed on the inner surface of a glass bulb and a visible light in the ultraviolet and short wavelength regions on the reflective layer. A light emitting layer which is excited by light and emits visible light in a wavelength range longer than that of the excitation light is provided. The second invention of the present invention is that the light emitting layer is activated by manganese. Magnesium fluoride germanate phosphor, europium-activated strontium chlorocalcium barium magnesium phosphor, europium-activated strontium phosphite phosphor, europium-activated strontium chlorosilicate phosphor, europium -One or more selected from the group consisting of Rhodium-activated barium-magnesium aluminate phosphor and Europium-activated strontium aluminate phosphor. Which is characterized by being configured by the phosphor, a third invention is characterized in that setting the deposition amount of the reflective layer in the range of 0.1~3.2mg / cm ² .

[0016]

According to this structure, visible light in the short wavelength range is amplified and reflected by the reflection layer made of magnesium oxide formed on the inner surface of the glass bulb, absorbed by the emission layer and excited with the ultraviolet ray. To do. Therefore, the light emitting layer emits a larger amount of visible light in the long wavelength region as compared with excitation by only ultraviolet light. Therefore, the luminous efficiency can be improved and the lamp cost can be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to FIG. In the figure, 1 is a glass bulb made of soda lime glass, lead glass, low lead glass or the like, and the inner surface thereof has a particle size of 0.5 to 5.0 μm, for example.
The reflective layer 2 made of magnesium oxide (MgO) and having a light-transmitting property is formed. The amount of magnesium oxide deposited on the reflective layer 2 per unit area is 0.1 to 3.2.
It is set in the range of mg / cm ² .

A light emitting layer 3 is formed on the reflective layer 2 in an overlapping manner. The light emitting layer 3 is mainly composed of 253.
In addition to being excited by 7 nm ultraviolet light, it is composed of a phosphor that is also excited by visible light in the short wavelength region (blue region).
In the fluorescent lamp of the illustrated example, the manganese-activated magnesium fluorogermanate phosphor (3.5MgO.0.5MgF.3) having the excitation spectrum and the emission spectrum (emission peak is 658 nm) shown by the dotted and solid lines in FIG. GeO
₂ : Eu) is used.

In addition to the above-mentioned manganese-activated magnesium fluorogermanate phosphor, the light-emitting layer 3 includes a europium-activated phosphor having the excitation and emission spectrum (emission peak is 480 nm) characteristics shown in FIG. - strontium phosphate phosphor _{(2SrO · 0.8P 2 O 5 ·} 0.16B 2 O 3: E
u), a europium activated strontium chlorosilicate phosphor (Sr 2 Si ₃ O ₈ .2SrC) having the excitation and emission spectra (emission peak is 490 nm) shown in FIG.
l ₂ : Eu), a europium-activated barium-magnesium aluminate phosphor (Ba _0.87 M) having the excitation and emission spectra (emission peak is 450 nm) shown in FIG.
g _2.0 Al ₁₄ O _3/31 : Eu), a europium-activated strontium aluminate phosphor (Sr ₄ ) having the excitation and emission spectra (emission peak is 490 nm) shown in FIG.
Al ₁₄ O ₂₅ : Eu), europium-activated strontium chlorophosphate / calcium / barium / magnesium phosphor and the like can be appropriately applied.

Next, the present inventor has found that the valve inner diameter is 15.5.
In a fluorescent lamp in which a reflective layer made of magnesium oxide is formed on the inner surface of a glass bulb of mm, and a light emitting layer made of manganese activated magnesium fluorogermanate phosphor is formed on the reflective layer, the amount of the reflective layer deposited 0-4.
435,658 nm when changed in the range of 0 mg / cm ^2.
When the radiation intensity of all the luminous fluxes was measured, the results shown in Table 3 were obtained. The fluorescent lamp of the lamp NO1 is a conventional product that does not have a reflective layer made of magnesium oxide.
The radiation intensity at 35,658 nm was set as 100 for comparison.

[0021]

[Table 3]

According to this result, in the fluorescent lamps of NO2 to NO10, the radiation intensity at 435 nm decreases with an increase in the amount of magnesium oxide deposited, but the radiation intensity at 658 nm increases conversely. Wearing amount is 0.5mg / cm ²
Above, it is almost saturated). However, although the total luminous flux is increased in the fluorescent lamps of NO2 to NO7,
It is decreasing in the fluorescent lamps of NO8 to NO10.

Therefore, from this result, the deposition amount of magnesium oxide was 65 in the range of 0.1 to 3.2 mg / cm ^2.
It can be seen that the effect of improving the radiation intensity of the total luminous flux of 8 nm can be expected, but it cannot be expected outside the range. This means that, on the other hand, if the total luminous flux of the conventional product is equal, the amount of the magnesium fluorogermanate phosphor used can be reduced by that amount. Therefore, the lamp cost can be reduced.

The present invention is not limited to the above-mentioned embodiment, and the fluorescent lamp can be applied to not only the straight tube type but also the ring type, the U-type, etc. Things are also available. Further, the respective phosphors can be used by appropriately mixing them.

[0025]

As described above, according to the present invention, since the reflection layer made of magnesium oxide is interposed between the glass bulb and the light emitting layer, the utilization efficiency of visible light in the short wavelength region is increased. Moreover, since a phosphor that is excited not only by ultraviolet rays but also by visible light in the short wavelength region is applied to the light emitting layer, visible light in the long wavelength region can be effectively emitted. Therefore, not only the luminous efficiency can be improved, but also the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a spectrum diagram showing an excitation spectrum and an emission spectrum of a magnesium fluorogermanate phosphor.

FIG. 3 is a diagram showing a spectral reflectance of magnesium oxide.

FIG. 4 is a spectrum diagram showing an excitation spectrum and an emission spectrum of a europium-activated strontium phosphite phosphor.

FIG. 5 is a spectrum diagram showing an excitation spectrum and an emission spectrum of europium-activated strontium chlorosilicate phosphor.

FIG. 6 is a spectrum diagram showing an excitation spectrum and an emission spectrum of a europium-activated barium-magnesium aluminate phosphor.

FIG. 7 is a spectrum diagram showing an excitation spectrum and an emission spectrum of a europium-activated strontium aluminate phosphor.

[Explanation of symbols]

 1 glass bulb 2 reflective layer 3 light emitting layer

Claims (3)

[Claims] 1. A reflection layer made of magnesium oxide formed on the inner surface of a glass bulb, and light emission that is excited by ultraviolet rays and visible light in the short wavelength range on the reflection layer and emits visible light in the longer wavelength range than the excitation light. A fluorescent lamp having a layer. 2. The light-emitting layer comprises manganese-activated magnesium fluorogermanate phosphor, europium-activated strontium chlorophosphate / calcium / barium-magnesium phosphor, europium-activated strontium folinate phosphor. , One or more phosphors selected from the group consisting of europium-activated strontium chlorosilicate phosphor, europium-activated barium magnesium aluminate phosphor, and europium-activated strontium aluminate phosphor. The fluorescent lamp according to claim 1, which is configured. 3. The amount of the reflective layer deposited is 0.1 to 3.2 mg.
The fluorescent lamp according to claim 1, wherein the fluorescent lamp is set in a range of / cm ² .