JPH079797B2 - Incandescent light bulb - Google Patents

Description

TECHNICAL FIELD The present invention relates to an incandescent light bulb having an infrared reflective film formed on the outer surface of a package.

[Prior art and its problems]

When an infrared reflective film that transmits visible light but reflects infrared light is formed on the outer surface of the incandescent lamp envelope, the infrared light emitted from the filament is returned to the filament by the infrared reflective film and the heat is reused. In addition, the luminous efficiency is improved and it is effective for power saving, and it is partially put to practical use. Conventionally, this infrared reflective film has a thickness of about 0.1 μm
iO ₂ film and has a SiO ₂ film is obtained by coating the multilayer, the boundaries of the TiO ₂ film having a high refractive index (approximately n = 2.1-2.4), and SiO ₂ film of a small refractive index (n = 1.45) Infrared is reflected by the surface. Then, in order to enhance the infrared reflection efficiency and ensure the effect, these films usually need to be a multilayer film of 6 layers or more.

By the way, this TiO ₂ has a transparent anatase phase in order to transmit visible light, but this anatase phase is a tetragonal metastable phase and is heated to a high temperature of 800 ° C. or higher. And a phase change to the rutile phase, which is a stable tetragonal phase, and becomes cloudy. On the other hand, an incandescent light bulb has a temperature of 1000 ° C on the outer surface of the envelope when it is lit up in a lamp with a small internal volume.
However, due to this, TiO ₂ undergoes a phase transformation from the anatase phase to the rutile phase, and the infrared reflective film becomes cloudy. An incandescent light bulb is required to have characteristics such as total luminous flux and color temperature at the time of lighting that do not change from those at the beginning even if it is lit for a long time, but if the infrared reflection film formed on the outer surface of the envelope becomes cloudy, The transmittance of visible light is reduced and the total luminous flux is reduced. Further, there is a problem that the spectral transmittance of the infrared reflection film changes during lighting, and the color temperature changes. Furthermore, if the infrared reflective film is a multi-layered film having six or more layers, the multi-layered film may peel off.

[Object of the Invention]

Therefore, according to the present invention, the infrared reflective film formed on the outer surface of the encapsulant does not become cloudy and the characteristics are not deteriorated even if it is illuminated at a high temperature for a long time. Intended to provide incandescent light bulbs.

[Structure of Invention and Its Action]

The structure of the present invention is an incandescent light bulb in which an infrared reflection film that transmits visible light but reflects infrared light is formed on the outer surface of the envelope, and the infrared reflection film has a ZrO ₂ molar ratio of 5 to 15. % TiO ₂ film mixed, that is, ZrO ₂ (mol) / [ZrO ₂ (mol) + TiO ₂ (mol)] × 100 = 5 to 15% TiO ₂ film mixed with ZrO ₂ and SiO ₂ film And a multi-layer film.

That is, since the lower limit of 5% or more of ZrO _{2 in a} molar ratio is mixed in the TiO ₂ film, the stability of the anatase phase, which is a metastable phase, increases, and the transformation start temperature from the anatase phase to the rutile phase is 1000 ℃ or more. Therefore, even if the incandescent light bulb is lit at high temperature for a long time, since the TiO ₂ does not undergo phase transformation, the infrared reflection film formed on the outer surface of the envelope does not become cloudy, and there is no deterioration in characteristics such as total luminous flux. The spectral transmittance does not change either. Next, since the upper limit of the amount of ZrO ₂ mixed is 15% or less in terms of molar ratio, the amount of ZrTiO ₄ produced in the TiO ₂ film is small and the refractive index hardly decreases. Therefore, the difference in refractive index between the TiO ₂ film and the SiO ₂ film is still maintained, and the infrared light reflectivity is not hindered. Furthermore, since ZrO ₂ is mixed, the multi-layered film is less likely to peel even if it has a multi-layer structure of 6 layers or more.

〔Example〕

The present invention will be specifically described below based on the embodiments shown in the drawings.

The drawing shows an incandescent lamp for general lighting with a rating of 110V and 65W, but a crimp sealing part 11 is formed at one end of a quartz glass envelope 1, and a pair of molybdenum foils are formed on the crimp sealing part 11. Two
Is buried. One end of each of the pair of inner lead rods 3 fixed to the glass piece 12 in the envelope 1 has a molybdenum foil 2 respectively.
Are welded to each other, and both ends of the filament 4 are electrically connected to these internal lead rods 3 and held along the axis of the envelope 1. Further, one end of the pair of external lead bars 5 is welded to the molybdenum foil 2 and extends to the outside of the pressure-bonding sealing portion 11. An infrared reflection film 6 is formed on the outer peripheral surface of the envelope 1.

Explaining the method of forming this infrared reflecting film 6, first, Zr
The encapsulant 1 was dipped into a Ti alcoholate solution containing 5 to 15% of Ti in a molar ratio with respect to Ti, dried at 150 ° C. for about 10 minutes, and then baked at about 600 ° C. for about 10 minutes to give a film thickness of 0.1.
A TiO ₂ film mixed with ZrO _{2 of} about μm is formed. next,
This sealing body 1 is again dipped in a Si alcoholate solution, and a SiO ₂ film is formed in layers on the TiO ₂ film by the same drying and firing operations. Then, this operation is repeated to form a TiO ₂ film mixed with ZrO ₂ and a SiO ₂ film in a multilayer of 6 to 10 layers.

Here, if the mixed amount of ZrO ₂ is less than 5% in molar ratio, Ti
The rise in the transformation start temperature of the O ₂ film from the anatase phase to the rutile phase is small, and if the incandescent lamp is lit at high temperature for a long time,
The infrared reflective film 6 may become cloudy, and the object of the present invention cannot be achieved. Next, when the mixing amount of ZrO ₂ exceeds 15%, the molar ratio, the number of the amount of ZrTiO ₄ in TiO ₂ film, closer to the refractive index of the SiO ₂ film refractive index of the TiO ₂ film is reduced To do. Therefore, the infrared light reflectivity of the infrared reflective film 6 is lowered, and, after all, the amount of ZrO ₂ mixed must be 5 to 15% in terms of molar ratio.

Then, the incandescent light bulb having such a configuration is turned on, but since the infrared light reflecting ability of the infrared reflecting film 6 is sufficient, the light emitting efficiency is improved by the action, and the entire luminous flux forms the infrared reflecting film. It is equivalent to a 110V, 75W incandescent light bulb, and could achieve about 15% power saving. The infrared reflective film 6 does not become cloudy even after being lit at a high temperature of about 1000 ° C. for several thousand hours, and therefore, the characteristics such as the total luminous flux are not deteriorated and the spectral transmittance is not changed even in the initial stage. Further, even when the infrared reflective film 6 was a multilayer of 6 layers or more, the multilayer film was not peeled off.

〔The invention's effect〕

As described above, the incandescent light bulb of the present invention has the infrared reflective film formed on the outer surface of the encapsulant, wherein ZrO ₂ is 5 to 15% in molar ratio.
Since it consists of a mixed TiO ₂ film and a multilayer film of SiO ₂ film,
It is possible to suppress the transformation of TiO _{2 into} the rutile phase without lowering the infrared light reflectivity of the infrared reflective film. Therefore, 10
Even if it is lit at a high temperature of about 00 ° C for a long time, the infrared reflection film formed on the outer surface of the envelope does not become cloudy and the transmittance of visible light does not decrease, and the spectral transmittance does not change. Can be an incandescent lamp in which the multilayer film does not peel even if the infrared reflective film has a multilayer structure of 6 layers or more.

[Brief description of drawings]

 The drawings are cross-sectional views of an embodiment of the present invention. 1 ... Enclosure, 6 ... Infrared reflective film

Claims (1)

[Claims] 1. An incandescent light bulb having an infrared reflection film that transmits visible light but reflects infrared light formed on the outer surface of an envelope, wherein the infrared reflection film contains ZrO ₂ in a molar ratio of 5 to 15%. An incandescent light bulb comprising a multi-layer film of a mixed TiO ₂ film and a SiO ₂ film.