JPH06290759A - Lamp - Google Patents

Abstract

PURPOSE:To extend a life of a halogen lamp. CONSTITUTION:A filament 7 wound in a coil shape is sealed inside a glass bulb 3, and an infrared reflecting film 8 is formed in an external surface of the glass bulb 3. In the glass bulb 3, its thickness is changed to form an external shape in almost a spherical shape and an internal surface in almost an ellipsoid of revolution. A visual light beam, radiated by the filament 7, passes through the infrared reflecting film 8. An infrared ray, radiated by the filament 7, is reflected by the infrared reflecting film 8 and fed back to the filament 7. Thus by dispersing the infrared ray fed back to the filament 7, a hot spot is prevented from being generated in the filament 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp in which an optical interference multilayer film is formed on a glass bulb.

[0002]

2. Description of the Related Art Conventionally, a filament formed by winding a tungsten wire into a coil is sealed inside a glass bulb having a substantially spherical shape, and the outer surface of the glass bulb transmits visible light and infrared rays. A halogen lamp having a reflecting optical interference multilayer film is known. And
In this halogen lamp, infrared rays radiated from the filament are reflected by the optical interference multilayer film and returned to the filament, thereby heating the filament and improving the luminous efficiency of the lamp.

[0003]

As described above, when an optical interference multilayer film is formed on a glass bulb having a substantially spherical shape, infrared rays reflected by the optical interference multilayer film are
It is concentrated in the central part of the glass bulb, that is, the central part of the filament. There, the central portion of the filament is heated more than the other portions, the temperature rises, and so-called hot spot occurs. Then, in this hot spot, the evaporation of tungsten is promoted, the filament is broken earlier than other portions, and there is a problem that the life of the lamp is shortened.

The present invention has been made in view of the above points, and an object thereof is to provide a lamp having high luminous efficiency and long life.

[0005]

A lamp according to claim 1 comprises a glass bulb, a light source disposed inside the glass bulb, and an optical interference multilayer film formed on the glass bulb. The glass bulb has a substantially spherical outer shape and a substantially spheroidal inner shape.

According to a second aspect of the present invention, in the lamp according to the first aspect, the light source is a filament, which is formed by winding it in a coil shape at a predetermined pitch, and the pitch in the vicinity of the central portion in the longitudinal direction of the filament. Is set to be coarser than the pitch in the vicinity of both ends in the longitudinal direction of the filament.

The lamp according to claim 3 comprises a glass bulb having a substantially spherical shape, a filament disposed inside the glass bulb, and an optical interference multilayer film formed on the glass bulb. The pitch in the vicinity of the central portion in the longitudinal direction of the filament is set to be coarser than the pitch in the vicinity of both longitudinal end portions of the filament.

A lamp according to claim 4 is the lamp according to any one of claims 1 to 3, wherein the optical interference multilayer film is
It is an infrared reflective film that transmits visible light and reflects infrared light.

[0009]

In the lamp according to the first aspect of the present invention, since the light source is disposed inside the glass bulb having the optical interference multilayer film and the outer shape having a substantially spherical shape, the luminous efficiency of the lamp is improved. Since the inner shape of the glass bulb is formed in a substantially spheroidal shape, the infrared light reflected by the optical interference multilayer film is refracted when exiting from the spheroidal surface, and its energy is dispersed to part of the light source. Concentration on the light source is suppressed, and disconnection of the light source due to a rise in temperature of a part of the light source is suppressed.

In the lamp according to the second aspect, in addition to the function according to the first aspect, the light source is a filament, and the filament is wound at a coarse pitch in the vicinity of the central portion in the longitudinal direction and in the vicinity of both end portions in the longitudinal direction of the filament. Since it is wound in a denser pitch and formed into a coil, the temperature rise of the central portion of the filament, which is easily heated by the energy reflected by the optical interference multilayer film, is suppressed, and the disconnection of the filament is suppressed.

According to the third aspect of the present invention, the luminous efficiency of the lamp is improved because the filament is disposed inside the substantially spherical glass bulb on which the optical interference multilayer film is formed. The filament is wound at a coarse pitch in the vicinity of the central portion in the longitudinal direction, and is wound in a coil shape at a denser pitch in the vicinity of both ends in the longitudinal direction of the filament.
The temperature rise of the central portion of the filament, which is easily heated by the energy reflected by the optical interference multilayer film, is suppressed, and the filament disconnection is suppressed.

In the lamp according to the fourth aspect, in addition to the functions according to the first to third aspects, the optical interference multilayer film constitutes an infrared reflection film which transmits visible light and reflects infrared rays, and therefore the luminous efficiency of the lamp. Is further improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of the lamp of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a halogen lamp as a lamp. The halogen lamp 1 has a glass bulb 3 made of quartz glass or the like, and a tip portion 4 is formed at one end of the glass bulb 3. At the same time, the sealing portion 5 is formed at the other end.

The glass bulb 3 is filled with an inert gas and a trace amount of halogen group elements (I, Br, Cl, F), and the direction from the chip portion 4 to the sealing portion 5 is the axial direction. As a light source, a filament 7 as a light source formed by winding a tungsten (W) wire into a coil is sealed.

Further, the glass bulb 3 has a substantially spherical outer shape and a substantially spheroidal inner shape, and is formed so that the thickness dimension thereof continuously changes. That is, the inner shape of the glass bulb 3 is larger than the inner diameter dimension L ₁ in the axial direction from the tip portion 4 to the sealing portion 5,
The inner diameter dimension L ₂ across the center (equator) of the glass bulb 3 in the direction orthogonal to this axial direction is formed larger.

Further, an infrared reflection film 8 as an optical interference multilayer film is formed on the outer surface of the glass bulb 3.
The infrared reflecting film 8 is formed by using a dip method, a vacuum deposition method, an ion plating method, a sputtering method, a CVD method, or the like, as shown in FIG.
a high refractive index layer H composed of iO ₂ ) and silicon dioxide (Si
It is formed by alternately stacking low refractive index layers L made of O ₂ ).

The infrared ray reflection film 8 selectively transmits and reflects the light rays emitted from the filament 7. That is, visible light passes through the infrared reflection film 8 and is irradiated to the outside, and infrared light is reflected by the infrared reflection film 8 and returns to the filament 7 inside the glass bulb 3 to heat the filament 7. However, the luminous efficiency is improved.

A pair of cap pins 9 electrically connected to the filament 7 are projected from the sealing portion 5, and these cap pins 9 are electrically and mechanically mounted on a lamp socket (not shown). It is supposed to be done.

Further, according to the halogen lamp 1 of this embodiment, since the outer surface of the glass bulb 3 is formed in a spherical shape and the infrared reflection film 8 is formed on this outer surface, the filament 7 irradiates the lamp. The infrared rays can efficiently return to the filament 7 to heat the filament 7 and improve the luminous efficiency of the halogen lamp 1.

Further, since the thickness of the glass bulb 3 is formed so as to gradually change and the inner surface is formed into a spheroidal shape, the infrared rays reflected by the infrared reflecting film 8 are spheroidal shape. When it comes out from the inner surface, it is refracted and dispersed,
Focusing on one focal point, that is, the center of the glass bulb 3 is suppressed. Therefore, the occurrence of so-called hot spots is suppressed, the filament 7 is not locally heated and evaporated, as compared with a halogen lamp using a glass bulb whose inner surface is spherical and has a constant thickness.
The temperature of the filament 7 is made almost uniform to suppress disconnection,
The life of the halogen lamp 1 can be extended.

Next, with respect to the halogen lamp 1 of this embodiment and a conventional halogen lamp using a spherical glass bulb having a constant wall thickness, the experimental results of measuring the temperature distribution at each position of the filament are shown as follows. This will be described with reference to the graph of FIG.

The graph shown in FIG. 3 is obtained by measuring the temperature of each turn of the filament under the condition of base-up lighting, and assuming that these temperatures are 100 as the maximum temperature in this embodiment and the conventional example. In the case of the halogen lamp of the conventional example shown by the broken line A, the temperature is locally high at the central portion of the filament, but is shown by the broken line B. In the case of the halogen lamp of this example, it was found that a substantially uniform temperature distribution was realized over the entire length of the filament.

The life of the halogen lamp of the conventional example was 3000 hrs, while the life of the halogen lamp of the present example was 4000 hrs, which was confirmed to have the effect of extending the life of the lamp. .

Next, another embodiment of the present invention will be described with reference to FIGS.

In FIG. 4, reference numeral 11 is a halogen lamp, and this halogen lamp 11 has a glass bulb 12 made of quartz glass or the like, and a tip portion 14 is formed at one end of this glass bulb 12 and A sealing portion 15 is formed at the end.

The glass bulb 12 is filled with an inert gas and a trace amount of halogen group elements (I, Br, Cl, F), and the direction from the chip portion 14 to the sealing portion 15 is the axial direction. As a filament, a filament (17) formed by winding a tungsten (W) wire into a coil at a predetermined pitch is sealed.

The filament 17 is wound so that the pitch on both ends becomes dense and the pitch becomes coarser toward the center. That is, as shown in FIG.
Assuming that the spacing between the turns of the filament 17 from one end side to the other end side is P _{1 to} P _{m + m} (where m is an integer), these P _{1 to} P _{m + m} are P ₁ <P ₂ < P ₃ <... <P _m = P _{m + 1} >...> P _{m + m-2} >
P _{m + m-1>} and _{P m + m, P 1 =} P m + m, P 2 = P m + m-1, P 3 = P m + m-2, ...,
P _m-1 = P _{m + 2} and P _m = P _{m + 1} .

Further, on the outer surface of the glass bulb 12, as shown in FIG.
The infrared ray reflecting film 8 similar to that shown in FIG. 2 is formed, and the visible light emitted from the filament 17 passes through the infrared ray reflecting film 8 and is emitted to the outside, and the infrared ray is reflected by the infrared ray reflecting film 8. Then, it is fed back to the filament 7 inside the glass bulb 3 to heat the filament 7 and enhance the luminous efficiency.

From the sealing portion 15, molybdenum (M
o) A pair of base pins 21 electrically connected to the filament 17 via the foil 20 are provided in a protruding manner, and the base pins 21 are electrically and mechanically attached to a lamp socket (not shown). There is.

Further, according to the halogen lamp 11 of this embodiment, since the outer surface of the glass bulb 12 is formed in a spherical shape and the infrared reflection film 8 is formed on this outer surface, irradiation from the filament 17 is performed. Further, the infrared rays can efficiently return to the filament 17 to heat the filament 17 and improve the luminous efficiency of the halogen lamp 11.

Further, the infrared rays reflected by the infrared reflecting film 8 tend to concentrate at the center of the spherical glass bulb 3, but the filament 17 has a dense pitch on both ends,
Since the winding is performed such that the pitch becomes coarser toward the center, it is possible to suppress an excessive temperature rise in the central portion of the filament 17. Therefore, in comparison with halogen lamps that use filaments wound at a fixed pitch, the occurrence of so-called hot spots is suppressed.
Filament is not locally heated and evaporated
It is possible to make the temperature of 17 substantially uniform, suppress the disconnection, and prolong the life of the halogen lamp 11.

Next, regarding the halogen lamp 11 of this embodiment and a halogen lamp as a conventional example using a filament having an infrared reflection film formed on a glass bulb and wound at a constant pitch, The experimental result of measuring the temperature distribution at each position will be described with reference to the graph of FIG.

The graph shown in FIG. 6 is obtained by measuring the temperature of each turn of the filament under the condition of base-up lighting, and setting these temperatures to 100, which is the maximum temperature in the present example and the conventional example. In the case of the conventional halogen lamp shown by the polygonal line C, the temperature is locally high at the central portion of the filament, but is shown by the polygonal line D. In the case of the halogen lamp of this example, it was found that a substantially uniform temperature distribution was realized over the entire length of the filament.

Then, the halogen lamp of this embodiment described above.
Table 1 shows the results of comparison of the lamp characteristics and the lamp life of the 11 and conventional halogen lamps with a so-called clear lamp, which is a halogen lamp in which an infrared reflection film is not formed on the glass bulb.

[0036]

[Table 1] From the above experiments, it was confirmed that the halogen lamp 11 of the present embodiment has substantially the same lamp characteristics as the conventional halogen lamp and has a longer lamp life than the conventional lamp.

The glass bulb 3 shown in FIG.
And by combining the filament 17 shown in FIG. 5, the life of the halogen lamp can be further extended. In each of the above embodiments, the filaments 7 and 17 are arranged along the axis connecting the chip portions 4 and 14 of the glass bulbs 3 and 12 and the sealing portions 5 and 15. Can be arranged, for example, in a wound state with the direction orthogonal to this axis as the central axis.

[0038]

According to the lamp of the first aspect, since the light source is disposed inside the glass bulb which has the optical interference multilayer film and has a substantially spherical outer shape, the luminous efficiency of the lamp can be improved. Since the inner shape of the glass bulb is formed into a substantially spheroidal shape, the infrared rays reflected by the optical interference multilayer film are refracted as they exit the surface of the spheroidal shape, and their energy is dispersed to a part of the light source. Concentration is suppressed.
Therefore, it is possible to prevent the temperature of a part of the light source from rising and breaking the wire, and it is possible to extend the life of the lamp.

According to the lamp of claim 2, claim 1
In addition to the effects described, the light source is a filament, and the filament is wound at a coarse pitch in the vicinity of the central portion in the longitudinal direction and is wound in a denser pitch in the vicinity of both ends in the longitudinal direction to form a coil shape. Therefore, the temperature rise of the central portion of the filament, which is easily heated by the energy reflected by the optical interference multilayer film, can be suppressed, the disconnection of the filament can be suppressed, and the life of the lamp can be extended.

According to the lamp of the third aspect, since the filament is arranged inside the glass bulb having a substantially spherical shape on which the optical interference multilayer film is formed, the luminous efficiency of the lamp can be improved. The filament is wound with a coarse pitch near the central portion in the longitudinal direction and is wound into a coil shape with a denser pitch in the vicinity of both longitudinal end portions of the filament, so that the filament is heated by the energy reflected by the optical interference multilayer film. It is possible to suppress the temperature rise of the central portion of the filament, which is easily affected, and to prevent the filament from breaking, thereby extending the life of the lamp.

According to the lamp of claim 4, claim 1
In addition to the effects described in Nos. 3 to 3, the optical interference multilayer film constitutes an infrared reflection film that transmits visible light and reflects infrared light, so that the luminous efficiency of the lamp can be further improved.

[Brief description of drawings]

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

FIG. 2 is a partial sectional view of the same.

FIG. 3 is a graph showing the experimental results of measuring the temperature distribution of the filament.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing the same filament.

FIG. 6 is a graph showing the experimental results of measuring the temperature distribution of the filament.

[Explanation of symbols]

 1,11 Halogen lamp as lamp 3,12 Glass bulb 7,17 Filament as light source 8 Infrared reflection film as optical interference multilayer film

Claims (4)

[Claims] 1. A glass bulb, a light source disposed inside the glass bulb, and an optical interference multilayer film formed on the glass bulb, wherein the glass bulb has a substantially spherical outer shape. , A lamp whose inner shape is substantially spheroidal. 2. The light source is a filament, which is formed by winding it into a coil at a predetermined pitch, and the pitch in the vicinity of the central portion in the longitudinal direction of the filament is larger than that in the vicinity of both ends in the longitudinal direction of the filament. The lamp according to claim 1, characterized in that the lamp is also coarsely set. 3. A glass bulb having a substantially spherical shape, a filament disposed inside the glass bulb, and an optical interference multilayer film formed on the glass bulb, wherein a central portion in the longitudinal direction of the filament. The lamp is characterized in that the pitch in the vicinity is set to be coarser than the pitch in the vicinity of both ends in the longitudinal direction of the filament. 4. The optical interference multilayer film transmits visible light,
The lamp according to any one of claims 1 to 3, wherein an infrared reflecting film for reflecting infrared rays is formed.