JP2000123795A - Incandescent lamp having infrared reflecting film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve a problem hard to solve easily because of generation of reflected light in a visible light range to deteriorate a color rendering property by composing multiple kinds of reflecting films with only conventional SW reflecting films to increase the feedback amount to an infrared filament and thereby to further improve the luminous efficiency of this kind of incandescent lamp. SOLUTION: This incandescent lamp 1 having an infrared reflecting film has a structure wherein the infrared reflecting film is so formed that an infrared-ray having a wavelength in the range of 750-1300 nm is reflected by at least one kind of multiple layers of an SW type reflecting film 4 composed by alternately laminating multiple low refraction-index films L and high refraction-index films H each having a film thickness of 1/4 of a desired wavelength, and an infrared-ray having a wavelength in the range more than 1300 nm is reflected by at least one kind of multiple layers of a five-layer type reflecting film 5 in a five-layer period form of which film thicknesses are defined respectively for a desired wavelength, so that reflection is not generated in a visible light range even if infrared-rays in a wide wavelength range are fed back to a filament.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incandescent lamp using a filament as a light emitting source, and more particularly, to an infrared reflecting film for reflecting an infrared ray in a light beam emitted from the filament to a bulb and returning the reflected light to the filament. The present invention relates to an incandescent lamp in which the temperature of the filament is further increased to improve the efficiency.

[0002]

2. Description of the Related Art FIG. 7 shows an example of the configuration of a conventional incandescent lamp 90 of this kind in a main part. A metal oxide film L having a low refractive index (for example, SiO ₂ or the like) is provided on the outer surface of a bulb 91. )
And a metal oxide film H having a high refractive index (for example, TiO ₂ or the like)
The infrared reflection film 92 is formed by alternately stacking 8 to 20 layers having a film thickness of １ ／ wavelength of the infrared light intended for reflection, for example, by means of vapor deposition, sputtering, CVD or the like. ing.

[0003] In this way, the filament 93
Of the light radiated from the infrared reflective film 92 is reflected and returned to the filament 93, whereby the temperature of the filament 93 rises, the luminous efficiency rises, and the same A bright incandescent lamp 90 can be obtained even with power consumption.

Accordingly, the efficiency can be expected to be improved as the amount of infrared rays fed back to the filament 93 is increased.
2,000 nm infrared reflective film 92A, and set wavelength 1500
By laminating a plurality of types such as an infrared reflection film 92B of nm, a more efficient incandescent light bulb 9 can be obtained.
It is likely to be 0.

Incidentally, the infrared reflecting film 92 is formed of [L / 2,
[H, L / 2] is often formed as one cycle, and the completed infrared reflection film 92 is formed as [L / 2, H, L, H,
..., H, L, H. L / 2], a metal oxide film L having a low refractive index and a thickness of １ ／ wavelength is provided on both surfaces. In this case, the valve 91
L / 2, which is closer, may be omitted. Thus, the infrared reflection film 92 basically formed by laminating the metal oxide film L having a low refractive index and the metal oxide film H having a high refractive index having the same thickness is generally called an SW type. Have been.

[0006]

However, in the above-described conventional infrared reflecting film 92, an infrared reflecting film 92A having a set infrared wavelength of 1000 nm and an infrared reflecting film 92B having a set infrared wavelength of 1500 nm are used. Is combined with the wavelength 5 as shown by the curve P in FIG.
Reflection occurs near 00 nm.

At this time, the human luminous efficiency is 380 to 380.
Since the light of the wavelength of 780 nm is reflected and not emitted to the outside, light of a part of the color missing from the incandescent lamp 90 is emitted from the incandescent lamp 90 (for reference, the light of the wavelength of 500 nm is
It approximates green, the three primary colors of light. ) The color rendering property is significantly impaired, and it cannot be put to practical use. Therefore, at present, only one type of the infrared reflecting film 92 having a set wavelength of around 1000 nm can be provided, and the wavelength range of the infrared light that can be returned to the filament 93 is also narrow. There is a problem that the efficiency cannot be improved as expected.

[0008]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, a bulb is provided with an infrared reflecting film for returning infrared rays in a light beam emitted from the filament to the filament. In the incandescent lamp with an infrared reflective film, the infrared reflective film has a low refractive index film L and a high refractive index film H each having a wavelength range of 750 to 1300 nm each having a quarter wavelength thickness of a desired wavelength. A five-layer reflective film that is reflected by at least one type of SW-type reflective films alternately stacked in a plurality of layers and has a wavelength of 1300 nm or more, each having a five-layer cycle in which a film thickness for a desired wavelength is defined. The present invention solves the problem by providing an incandescent lamp with an infrared reflective film, characterized in that reflection is performed by at least one of a plurality of layers.

[0009]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 and 2 show a basic configuration of the present invention. In the present invention, an infrared reflective film is provided on the outer surface of a bulb 2 of an incandescent lamp 1 with an infrared reflective film (hereinafter simply referred to as an incandescent lamp 1). This is similar to the conventional example in that the infrared ray is fed back to the filament 3 by this infrared reflection film to improve the luminous efficiency.

Here, in the present invention, as in the conventional example, the infrared reflecting film has 1/1 of the wavelength of the infrared light intended for reflection.
A low-refractive-index film L formed of, for example, SiO ₂ (refractive index: 1.46) and a high-refractive-index film H formed of, for example, Ta ₂ O ₅ (refractive index: 2.2). In addition to the so-called SW-type infrared reflection film 4 (hereinafter referred to as SW-type reflection film 4), which is laminated an appropriate number of times, a five-layer periodic infrared reflection film 5 (hereinafter, referred to as a SW-type reflection film 4) which is laminated an appropriate number of times. (Referred to as a layer type reflection film 5). Incidentally, the SW type reflection film 4 is formed as [L / 2, H, L /
2] as one cycle.

The five-layer type reflection film 5 has [L / a, H / b,
L / c, H / d, L / a]. At this time, each numerical value a, b, c, d is 2 ≦ a ≦
It is set within the range of 5, 4 ≦ b ≦ 25, 4 ≦ c ≦ 25, and 1 ≦ d ≦ 3 to obtain reflection characteristics with respect to infrared light having a desired wavelength. Incidentally, as an example, the numerical values when the wavelength is 1700 nm for infrared rays are a = 2.6, b = 10, c = 6.5,
A combination such as d = 1.3 is obtained.

In the present invention, the SW-type reflective film 4 is used for the infrared wavelength range of 800 to 1300 nm which does not cause secondary reflection in visible light (380 to 780 nm) even if the SW-type reflective film 4 is used. And 130
For the infrared light of 0 nm or more, the five-layer type reflection film 5 is employed.

The basic configuration of the incandescent lamp 1 of the present invention has been described above. In actual implementation, one type of the SW-type reflective film 4 having a wavelength within the above range (800 to 1300 nm), The wavelength is 1300 as the layer type reflection film 5
one of those set to nm or more, or SW-type reflective film 4
One of the five types in which the wavelength is set within the above range, one type in which the wavelength is set to 1300 nm or more as the five-layer reflective film 5, and the other one in which the wavelength is set in the above range as the SW type reflective film 4. The five types of reflective films 5 may be combined as two types, that is, one having a wavelength set to 1300 nm or more.

FIG. 3 shows a first embodiment of the present invention in which one type of the above-mentioned SW type reflection film 4 and one type of the five-layer type reflection film 5 are combined. The reflection film 4 is formed as three layers with a reflection wavelength λ1 set to 950 nm, and the five-layer reflection film 5 is formed as three layers with a reflection wavelength λ2 set at 1300 nm. FIG. 4 shows the reflection (transmission) characteristic T1 in the above configuration.
It is. still. At this time, for the five-layer reflective film 5, a = 2.4, b = 10, c = 7.5, and d = 1.2 are set, and the above-mentioned reflection wavelength is obtained. .

According to the present invention, as is apparent from FIG. 4, there is no noticeable drop in transmittance with respect to visible light having a wavelength in the range of 380 to 780 nm. Since the color rendering properties do not decrease, and the infrared rays are reflected in a wide range of wavelengths from 800 to 1500 nm, it is possible to expect a corresponding improvement in luminous efficiency.

FIG. 5 shows a second embodiment of the present invention in which two types of SW type reflection films 4 and one type of five-layer type reflection film 5 are combined. , Reflection wavelength λ
3 is set to 950 nm, and the first SW-type reflective film 4a having three layers
And a four-layer second SW-type reflective film 4b having a reflection wavelength λ4 of 1150 nm. The five-layer reflective film 5 is formed as three layers with a reflection wavelength λ5 of 1700 nm. And the reflection (transmission) in the above configuration
FIG. 6 shows the characteristic T2.

Also at this time, as shown in FIG. 6, a noticeable drop in transmittance does not occur for visible light having a wavelength in the range of 380 to 780 nm, and the color rendering property is lowered. No, wavelength of 800-1850 nm for infrared
Therefore, the light emission efficiency can be expected to be equal to or higher than that of the first embodiment. Although illustration is omitted, as described above, S
Even when one type of the W-type reflective film 4 and two types of the five-layer type reflective film 5 are combined, the same operation and effect as described above can be obtained.

[0018]

As described above, according to the present invention, the infrared reflective film has a low refractive index film L and a high refractive index film each having a wavelength range of 750 to 1300 nm each having a quarter wavelength thickness of a desired wavelength. The film H is alternately reflected by at least one of a plurality of SW-type reflective films in which a plurality of layers are stacked alternately, and a wavelength range of 1300 nm or more is defined as a five-layer cycle in which a film thickness for a desired wavelength is defined. At least one of a plurality of layers of the layered reflective film
By using an incandescent lamp with an infrared reflective film that reflects light depending on the type, it is possible to increase the amount of infrared light returning to the filament by configuring multiple types using only the conventional SW-type reflective film. It solves the problem that color rendering is impaired due to the generation of reflected light within the lamp, making it infeasible, further improving the luminous efficiency of this kind of incandescent lamp, and having an extremely excellent effect in improving performance. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a basic configuration of an embodiment of an incandescent lamp with an infrared reflecting film according to the present invention.

FIG. 2 is an explanatory diagram showing a main part of the same embodiment in an enlarged manner.

FIG. 3 is an explanatory diagram showing a main part of the first embodiment of the incandescent lamp with an infrared reflective film according to the present invention.

FIG. 4 is a graph showing reflection (transmission) characteristics of the first embodiment.

FIG. 5 is an explanatory view showing a second embodiment of the incandescent lamp with an infrared reflective film according to the present invention in a main part.

FIG. 6 is a graph showing reflection (transmission) characteristics of the second embodiment.

FIG. 7 is an explanatory diagram showing a main part of a conventional example.

FIG. 8 is a graph showing reflection (transmission) characteristics of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Incandescent lamp with infrared reflective film 2 ... Bulb 3 ... Filament 4 ... SW type reflective film 5 ... 5 layer type reflective film H ... High refractive index film with a quarter wavelength film thickness L ... 1 Low refractive index film with a quarter wavelength thickness

Claims (2)

[Claims] 1. An incandescent lamp with an infrared reflection film, wherein a bulb is provided with an infrared reflection film for returning infrared light in a light beam emitted from the filament to the filament, wherein the infrared reflection film has a wavelength of 750 to 1300 nm. S in which a plurality of low-refractive-index films L and high-refractive-index films H each having a quarter wavelength thickness of a desired wavelength are alternately laminated.
It is reflected by at least one of the W-type reflective films and has a wavelength of 130
The reflection is performed by at least one of a plurality of layers of a five-layer reflective film in which a range of 0 nm or more has a five-layer cycle in which a film thickness for a desired wavelength is defined. Incandescent light bulb with infrared reflective film. 2. The configuration of the five-layer periodic infrared reflection film is [L / a, H / b, L / c, H / d, L / a] where 2 ≦ a ≦ 5, 4 ≦ b. ≦ 25, 4 ≦ c ≦ 25, 1 ≦
2. The incandescent lamp with an infrared reflecting film according to claim 1, wherein d ≦ 3.