JPH0636348B2 - High color rendering fluorescent lamp - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a high color rendering fluorescent lamp, and more particularly to a high brightness and high color rendering fluorescent lamp.

[Prior art]

In recent years, high color rendering fluorescent lamps have been in increasing demand as consumers' demands for improved light quality have increased. The reason is that the high color rendering fluorescent lamp exhibits higher brightness and higher color rendering than a conventional fluorescent lamp using a halo phosphor. However, the high color rendering type three-wavelength lamp is not widely used as a substitute for all general lighting lamps. The reason is that the high color rendering type lamp is considerably more expensive than the lamp using the halo phosphor. In particular, the phosphor used in the high color rendering type three-wavelength lamp is made of a rare earth element or a rare element, and the price thereof is about 10 to 50 times that of the halo fluorescent substance. It is a big cause of rising. Therefore, as a conventional method for reducing the price of this expensive high color rendering type three-wavelength fluorescent lamp, Japanese Patent Laid-Open No. Sho 53-53
The technique disclosed in Japanese Patent No. 867 has been proposed. In the fluorescent lamp shown in this publication, the light emitting layer is divided into two layers and applied. In this fluorescent lamp, a halo phosphor is applied to the inner surface of a glass tube to form a first layer, and a three-wavelength phosphor is applied to the surface thereof. With this structure, the amount of the three-wavelength phosphor used has been successfully reduced. Further, in the fluorescent lamp having this structure, sodium ions liberated from the glass bulb are adsorbed by the halo phosphor coated as the first layer to prevent the reaction between sodium ions and mercury and prevent the deterioration of the fluorescent lamp. Is also successful. The high color rendering fluorescent lamp having this structure can reduce the coating amount of the three-wavelength fluorescent material, but has a drawback that the halo fluorescent material emits light and the color rendering is deteriorated. This is because the ultraviolet light that has passed through the three-wavelength phosphor layer excites the halo phosphor layer to emit light. Therefore, the fluorescent lamp having this structure is slightly brighter than the fluorescent lamp coated with only the halo fluorescent material, but has a drawback that the color rendering property is deteriorated due to the change of the lamp spectrum due to the emission of the halo fluorescent material. FIG. 1 is a graph showing the luminous flux of a high color rendering fluorescent lamp coated with a halo phosphor layer and a three-wavelength phosphor layer and the average color rendering index (hereinafter referred to as Ra). However, in this graph, 2.0 g of the halo phosphor is applied to the first layer, and the second layer is a three-wavelength phosphor. 25% by weight of (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ · Cl: Eu, b. 40% by weight of LaPO ₄ : Ce, Tb, c. A three-wavelength phosphor containing 35% by weight of Y ₂ O ₃ : Eu mixed is applied. In addition, this graph is obtained by measuring the luminous flux and the average color rendering index by changing the coating amount of the above-mentioned three-wavelength phosphor on a fluorescent lamp (FL40SS lamp). As is clear from this graph, both the luminous flux and Ra decrease as the coating amount of the three-wavelength phosphor decreases. Especially Ra
Is significantly reduced. This is because as the coating amount of the three-wavelength phosphor with respect to the halo phosphor decreases, the absorptivity of the ultraviolet light of the three-wavelength phosphor layer decreases, and the ultraviolet light transmitted through the three-wavelength phosphor layer forms the first layer of the halo phosphor. This is because the layer is stimulated to emit light. That is, the high color rendering fluorescent lamp having this structure cannot satisfy all the properties of high color rendering, luminous flux and phosphor cost at the same time, and when the phosphor cost is reduced, the luminous flux and the color rendering are deteriorated.

[Problems to be Solved by the Present Invention]

The present invention was further developed with the object of solving this drawback, and an important object of the present invention is to provide a high color rendering type which can improve the luminous flux and the color rendering property in spite of reducing the raw material cost. To provide fluorescent lamps.

[Means for solving the problem]

In order to achieve the above object, the present invention realizes a high color rendering fluorescent lamp on the principle completely different from the conventional fluorescent lamp. That is, excellent color rendering properties and high luminous flux are realized by using the ultraviolet reflective layer that does not emit light by itself. In order to realize this, the high color rendering fluorescent lamp of the present invention has the following configuration. The high color rendering fluorescent lamp of the present invention emits light from the entire surface of the glass bulb.
A high color rendering fluorescent lamp is formed by coating a UV reflecting layer made of white powder of a non-luminous substance and a light emitting layer made of a plurality of phosphors having different emission colors on the UV reflecting layer in this order from the inner surface of the glass bulb. ing. The following phosphors are used in the light emitting layer in order to achieve excellent color rendering and high luminous flux. (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ · Cl: Eu
Phosphor, BaMg ₂ Al ₁₆ O ₂₇ : Eu phosphor, LaPO ₄ : Ce, Tb phosphor, MgAl ₁₁ O ₁₉ : Ce, Tb phosphor, Y ₂ SiO ₅ : Ce, Tb, phosphor Y ₂ O ₃ : Eu phosphor, Y (PV) O ₄ : Eu phosphor, 3.5MgO0.05MgF ₂ GeO ₂ : Mn phosphor and the like are used. The white powder has an average particle size of 50 nm to 2 μm.
The white powder having an average particle size of less than 50 nm has a particle size smaller than the wavelength of the ultraviolet light, so that the reflection efficiency of the ultraviolet light is reduced and the ultraviolet light transmitted through the light emitting layer cannot be reflected. The white powder having an average particle size of more than 2 μ has a large coating amount, resulting in high cost, and the luminous flux of the fluorescent lamp cannot be increased. The average particle size of the white powder is preferably 100n
When it is m or more, dispersion is easy and workability is good, and when it is 1 μm or less, the effect of the present invention can be sufficiently obtained without increasing the cost. A fluorescent lamp in which a protective film is applied between the light emitting layer and the glass bulb has been developed. The protective film of this fluorescent lamp is
The purpose is to prevent the reaction of sodium ions contained in soda glass with mercury to prevent the deterioration of the fluorescent lamp. The fluorescent lamp provided with the protective film irradiates the light emitted from the light emitting layer to the outside through the protective film. Therefore, the protective film is required to have excellent light transmittance. This is because when the protective film absorbs light, the luminous flux of the fluorescent lamp decreases. Therefore, a transparent film is used as the protective film.
In order to make the protective film transparent, alumina having extremely fine particles of 30 nm or less is used. The transparent protective film transmits visible light and has a low ultraviolet ray reflectance, and therefore cannot be used as the ultraviolet ray reflective layer of the present invention. Furthermore, the reflectance of the white powder at a wavelength of 200 nm or more is 80% or more when the MgO diffusion plate is 100%. As a white powder satisfying this characteristic, there is, for example, a mixture of silica, alumina, barium sulfate, calcium phosphate, etc. alone or in combination of plural kinds. Furthermore, the white powder is 0.05 to 0.05% on the inner surface of the glass bulb.
It is applied at a coating amount of 5 mg / cm ² . Coating amount is 0.05mg
If it is less than / cm ² , the predetermined effect of improving the luminous flux cannot be realized. Further, even if the coating amount exceeds 5.0 mg / cm ² , the luminous flux does not increase and the cost increases. Desirably, from the viewpoint of controlling the coating amount, 0.1 mg / cm ² or more is preferable, and 2.0 mg / cm ² or less causes no cost problem.

[Action]

In the high color rendering fluorescent lamp of the present invention, an ultraviolet reflecting layer that reflects the ultraviolet rays that have passed through the light emitting layer is provided between the fluorescent layer and the glass bulb. The ultraviolet ray reflective layer reflects the ultraviolet ray transmitted through the light emitting layer. The ultraviolet light reflected by the ultraviolet reflective layer transmits the light emitting layer and then excites the light emitting layer again. In particular,
The ultraviolet light reflected by the ultraviolet reflective layer causes the glass surface side of the light emitting layer, in other words, the outer surface of the light emitting layer to emit light, so that the light emitted here is emitted to the outside without passing through the light emitting layer. Achieve a high luminous flux. That is, the light emitting layer is efficiently excited by being excited by ultraviolet rays from both sides. Although there is an ultraviolet reflective layer for reflecting ultraviolet rays, it slightly attenuates the light emitted from the light emitting layer. If the amount of light attenuation of the ultraviolet reflective layer is high, the luminous flux of the fluorescent lamp cannot be increased even if this layer reflects ultraviolet light. However, the results of actual trial manufacture and measurement by the present inventors show that the amount of light attenuation of the ultraviolet reflective layer is smaller than that of the layer that reflects ultraviolet rays and raises the brightness of the light emitting layer. We have succeeded in increasing the luminous flux of the fluorescent lamp. Moreover, the ultraviolet ray reflection layer, which is extremely inexpensive as compared with the light emitting layer, improves the ultraviolet ray excitation efficiency of the light emitting layer and improves the luminous flux. The ultraviolet reflective layer also protects the light emitting layer as an additional function. That is, the ultraviolet reflection layer plays a role of preventing the reaction of sodium ions in the soda glass in the fluorescent lamp with mercury and preventing the deterioration of the fluorescent lamp.

[Preferred embodiment]

Hereinafter, the present invention will be specifically described with reference to examples. (Example 1) As shown in FIG. 2, the high color rendering fluorescent lamp was FL40.
An ultraviolet reflecting layer 2 is applied to the inner surface of the SS bulb 1, and a light emitting layer 3 is applied to the inner surface of the ultraviolet reflecting layer. White powder is applied to the ultraviolet reflective layer 2. The high color rendering fluorescent lamp shown in FIG. 2 uses “α-Al ₂ O ₃ ” having a white powder and an average particle size (measured by the F, S, S and S methods, the same applies hereinafter) of 0.3 μm. is doing. The amount of white powder applied is 1.0 g. The light emitting layer 3 is coated with 2 g of a three-wavelength phosphor. The three-wavelength phosphor includes (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ · Cl: E
A mixture of 10% u phosphor, 30% LaPO ₄ : Ce, Tb phosphor, and 60% Y ₂ O ₃ : Eu phosphor is used. This fluorescent lamp was a fluorescent lamp having a color temperature of 3000K. Table 1 shows the photometric results of the obtained high color rendering fluorescent lamp. In order to clarify the excellent characteristics of the high color rendering fluorescent lamps obtained in the examples, the halo phosphor and the three-wavelength phosphor are used in combination.
The characteristics of the high color rendering fluorescent lamp applied to the layers are shown as Comparative Example 1. As shown in the table, the high color rendering fluorescent lamp obtained in Example 1 has a luminous flux of 3637 Lm, which is 87 L compared to the comparative example.
m was also high, and Ra was 83.8, which was an improvement of 2.3 as compared with the comparative example. Further, the luminous flux maintenance factor after lighting for 500 hours was 95.5%, which was 1% higher than that of the comparative example. Example 2 A high color rendering fluorescent lamp was manufactured in the same manner as in Example 1 except that 1.0 g of CaP ₂ O ₇ having an average particle size of 0.6 μ was applied as an ultraviolet reflecting layer. The high color rendering fluorescent lamp obtained had a color temperature of 3000K. It became the FL40SS lamp. (Example 3) FL40 was carried out in the same manner as in Example 1 except that 2.4 g of BaSO ₄ having an average particle size of 0.8 μ was applied as an ultraviolet reflecting layer.
I got an SS lamp. (Examples 4 to 10) A high color rendering fluorescent lamp was performed in the same manner as in Example 1 except that the white powder applied to the ultraviolet reflective layer was changed and the amount of the three-wavelength phosphor applied to the light emitting layer was changed. Was manufactured. Luminous flux of the high color rendering fluorescent lamps obtained in Examples 2 to 10,
Table 1 shows the luminous flux maintenance factor after lighting for Ra for 500 hours. As shown in this table, in the high color rendering fluorescent lamps obtained in Examples 2 to 10, the luminous flux was 3540 to 3750 Lm, the Ra was 82.6 to 85.8, and the luminous flux maintenance factor was 94.4. It showed excellent characteristics of 96.2. (Example 11) UV-reflecting layer, using α-Al ₂ O ₃ having an average particle size of 0.3 micron, the coating amount of 1.8 g. 1 g of a three-wavelength phosphor is applied to the light emitting layer. The three-wavelength phosphor includes (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ · Cl: E
A mixture of 25% u phosphor, 30% LaPO ₄ : Ce, Tb phosphor, and 45% Y ₂ O ₃ : Eu phosphor is used. The color temperature of the obtained high color rendering fluorescent lamp is 5000K.
Became. (Examples 12 and 13) A high color rendering fluorescent lamp was manufactured in the same manner as in Example 11 except that the coating amount of the white powder and the coating amount of the three-wavelength phosphor of the ultraviolet reflecting layer were changed. The characteristics of the high color rendering fluorescent lamps obtained in Examples 11 to 13 are shown in Table 1. As shown in this table, the high color rendering fluorescent lamps obtained in these examples have a luminous flux of 3524 to 3629 Lm, Ra of 82.5 to 84.0, and luminous flux maintenance factor of 94.5. It showed excellent characteristics of 96.5.

【effect】

As can be seen from Table 1, the high color rendering fluorescent lamp of the present invention exhibits superior characteristics to the high color rendering fluorescent lamp (Comparative Example 1) in which a halo fluorescent material and a three-wavelength fluorescent material are applied. . In a conventional high color rendering fluorescent lamp in which a conventional halo phosphor and a three-wavelength phosphor are applied, the halo phosphor is excited by ultraviolet rays that have passed through the three-wavelength phosphor. On the other hand, in the high color rendering fluorescent lamp of the present invention, the ultraviolet rays transmitted through the light emitting layer are reflected and the light emitting layer is excited again. Compared with a conventional fluorescent lamp in which the ultraviolet light transmitted through the three-wavelength phosphor stimulates the halo fluorescent substance directly to emit light, the fluorescent lamp of the present invention that reflects the ultraviolet light transmitted through the light emitting layer and re-excites the light emitting layer is It is also considered that the luminous flux is reduced. Since the reflectance of ultraviolet rays cannot exceed 100%, the excitation energy can be increased by directly exciting the light emitting layer with the ultraviolet rays that have passed through the light emitting layer. However, in practice, the halo phosphor coated on the outer surface of the three-wavelength phosphor is limited in coating amount, and cannot be applied to a thickness that can sufficiently absorb the ultraviolet rays transmitted through the three-wavelength phosphor. This is because the halo fluorescent substance is required to have a light-transmitting property for transmitting the light emitted from the three-wavelength fluorescent substance. When the halo fluorescent substance absorbs the light emitted from the three-wavelength fluorescent substance, Ra of the fluorescent lamp is significantly lowered and the overall emission luminance is also lowered. The measurement data of the present invention demonstrate that the light emission by the ultraviolet reflection of the ultraviolet reflection layer is superior to the direct excitation of the halo phosphor. It will be described with reference to FIG. 3 and Comparative Example 2 in Table 1 that the luminous flux of the fluorescent lamp can be remarkably improved when the ultraviolet reflecting layer reflects ultraviolet rays to excite the light emitting layer. In FIG. 3, the reflectance of the powder is measured with the reflectance of the MgO diffusion plate being 100%. As you can see from this figure,
TiO ₂ has an extremely low reflectance in the ultraviolet region as compared with Al ₂ O ₃ , Ca ₂ P ₂ O ₇ , BaSO _{4 and the} like used as the ultraviolet reflective layer in the fluorescent lamp of the present invention. Therefore, the fluorescent lamp in which TiO ₂ is applied to the ultraviolet reflective layer has a low reflection amount of the ultraviolet light transmitted through the light emitting layer. Comparative example 2
In this fluorescent lamp, TiO ₂ is applied to the ultraviolet reflective layer. This fluorescent lamp is the same fluorescent lamp as in Example 1 except that TiO ₂ is applied to the ultraviolet reflective layer. Comparing Comparative Example 2 with the fluorescent lamp of Example 1, Ra is almost the same, but the luminous flux is 3637 Lm to 3247 Lm.
m and 390 Lm also decrease. This difference in luminous flux is an effect due to the ultraviolet ray reflecting layer reflecting ultraviolet rays and re-exciting the light emitting layer. In addition, the emission spectrum of the fluorescent lamp coated with the halo phosphor and the three-wavelength phosphor has an Ra lower than that of the pure three-wavelength spectrum because it includes the emission spectrum of the halo phosphor. However, in the high color rendering fluorescent lamp of the present invention, the ultraviolet light reflected by the ultraviolet reflective layer excites the light emitting layer again, so that it has only the emission spectrum of the light emitting layer and is excellent in Ra.
To realize. Also, in terms of cost, the material used for the ultraviolet reflective layer is much cheaper than the phosphor used for the light emitting layer, and can be manufactured at low cost. The present invention has been described above by taking the low-pressure mercury vapor discharge lamp as an example, but the present invention is not limited to this, and can be similarly applied to a high-pressure mercury vapor discharge lamp and other discharge lamps.

[Brief description of drawings]

FIG. 1 is a graph showing the luminous flux and the average color rendering index of the conventional FL40SS lamp with respect to the coating amount of the three-wavelength phosphor, FIG. 2 is a sectional view of the high color rendering fluorescent lamp, and FIG. 3 is Al ₂ O ₃ and Ca _2. P ₂ O ₇ , BaSO ₄ , TiO ₂
It is a graph which shows the ultraviolet reflectance of. 1 ... FL40SS bulb, 2 ... ultraviolet reflecting layer, 3 ... light emitting layer.

Claims (1)

[Claims] 1. A high color rendering fluorescent lamp that emits light from the entire surface of a glass bulb, wherein the fluorescent lamp comprises, in order from the inner surface of the glass bulb, an ultraviolet reflecting layer made of white powder of a non-luminous substance, and an ultraviolet reflecting layer thereof. A light emitting layer made of a plurality of phosphors having different emission colors is coated on the white powder, the white powder has an average particle diameter in the range of 50 nm to 2 μm, and the white powder has a reflectance at a wavelength of 200 nm or more. Is 80% when the MgO diffusion plate is 100%
A high color rendering fluorescent lamp having the above-mentioned reflectance and further characterized in that the white substance is coated on the inner surface of the glass bulb at a coating amount of 0.05 to 5 mg / cm ² .