JPH097553A - Incandescent light bulb and lighting device using the same - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an incandescent light bulb in which electric discharge and a short circuit are prevented from occurring between a pair of internal lead wires supported by a bridge glass, and a lighting device using the same. [Construction] A filament 8 is housed in a bulb 2 whose one end is sealed, and one end of a pair of internal lead wires 10, 11 whose other end is connected to the filament 8 is guided to a sealing part 3 and the sealing part 3 A bridge glass 9 is provided between the bridge glass 9 and the filament 8, the pair of internal lead wires 10 and 11 are spaced apart from each other at both ends of the bridge glass 9, and an anchor 12 is supported at an intermediate portion of the bridge glass 9. However, this anchor 12 is characterized by supporting the intermediate portion of the filament 8. Since the anchor is supported on the middle portion of the bridge glass and the pair of inner lead wires is supported on both end portions of the bridge glass, the inner lead wires are separated from each other and a discharge occurs between the inner lead wires. And a short circuit is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incandescent light bulb such as a single-sealed halogen light bulb and a lighting device using the same.

[0002]

2. Description of the Related Art In a single-sealed halogen light bulb, one end of a pair of internal lead wires, the other end of which is connected to a filament, is guided to a crushed sealing part formed at one end of a bulb, It is connected to a molybdenum foil that is sealed to.
In the case of such a single-sided bulb, since the filament has a structure in which it is cantilevered by a pair of internal lead wires, there is a tendency for the filament to become unstable, and an anchor is used to eliminate this. ing. The anchor consists of a wire, one end of which is fixed to the bridge glass and the other end of which is hooked on the middle part of the filament, which holds the middle part of the filament and prevents the filament from swinging even when shock or vibration is applied. It is supposed to suppress.

The bridge glass supporting the anchor is bridged between a pair of internal lead wires and fixed to the internal lead wires. That is, the bridge glass is installed in the middle of the pair of internal lead wires so as to straddle between them, and therefore the bridge glass mechanically connects the pair of internal lead wires to increase the rigidity of the entire mount. It also works to enhance. Therefore, the pair of inner lead wires and the anchor are fixed to the bridge glass.

[0004]

However, recently, improvements such as forming an infrared reflection film on a bulb of an incandescent light bulb have been advanced,
In particular, the efficiency of halogen bulbs has been improved.
Along with this, miniaturization of light bulbs is progressing. When the bulb is downsized, the bulb is also downsized and the bulb diameter at the location where the bridge glass is placed is also reduced. Therefore, the length of the bridge glass is also regulated.

In the conventional case, a pair of internal lead wires are fixed to the bridge glass so as to be adjacent to each other, and an anchor is fixed to an end portion of the bridge glass. That is, a pair of internal lead wires and anchors were attached to the bridge glass side by side in this order. In such a structure, the pair of internal lead wires are close to each other, and when the bridge glass is shortened as described above, the internal lead wires are arranged closer to each other, and the internal lead wires are There is a concern that the separation distance and the creepage distance will become small and discharge or short circuit will occur between them.

The present invention has been made in view of the above circumstances. An object of the present invention is to dispose a pair of internal lead wires supported by a bridge glass so as to be spaced apart from each other, thereby causing a discharge or a short circuit between them. It is intended to provide an incandescent light bulb in which heat generation is prevented and a lighting device using the same.

[0007]

According to a first aspect of the present invention, there is provided a valve having a sealing portion formed at one end; a filament housed in the valve; the other end connected to the filament, and the one end having the seal. A pair of internal lead wires guided to the stopper; a bridge glass provided in the bulb between the sealing portion and the filament, and a part of the pair of internal lead wires being supported apart from each other; An incandescent lamp having one end located between the pair of internal lead wires and fixed to the bridge glass, and the other end anchored in the middle portion of the filament. .

The shape of the bridge glass is not limited to an oval shape or a rod shape, and may be a disk shape or the like. Further, the present invention may be a light bulb in which an infrared reflection film is formed or a light bulb in which an infrared reflection film is not formed, and is not limited to a halogen light bulb.

The invention according to claim 2 is characterized in that the direction in which the anchor is led out from the bridge glass is a direction intersecting with a surface formed by the pair of internal lead wires and the bridge glass. It is an incandescent light bulb.

The invention of claim 3 is the incandescent light bulb according to claim 1 or 2, wherein the filaments are arranged vertically along the bulb axis. The invention according to claim 4 is the incandescent light bulb according to any one of claims 1 to 3, characterized in that the inner diameter of the bulb at the location where the bridge glass is arranged is 6.5 mm or less.

The invention according to claim 5 is characterized in that the distance between the pair of internal lead wires at a portion supported by the bridge glass is 2 mm or more, and the invention is defined by any one of claims 1 to 4. It is an incandescent light bulb.

According to a sixth aspect of the present invention, a valve has a sphere, an elliptic sphere, or a spherical portion similar thereto, a cylindrical portion continuous with the spherical portion and a sealing portion, and the filament is accommodated in the spherical portion. The incandescent lamp according to any one of claims 1 to 5, wherein the bridge glass is housed in the cylindrical portion.

An invention according to claim 7 is an illuminating device comprising: the incandescent lamp according to any one of claims 1 to 6; and a luminaire in which the incandescent lamp is incorporated. is there. The invention according to claim 8 is the lighting apparatus according to claim 7, wherein the lighting device has a reflector that reflects the light emitted from the incandescent lamp.

[0014]

According to the first aspect of the present invention, the pair of inner lead wires are supported by the end portions of the bridge glass, and the anchor is positioned between the pair of inner lead wires and is held in the central portion of the bridge glass. Therefore, the distance between the pair of internal lead wires becomes larger than that in the case where the pair of internal lead wires are arranged side by side on one end side of the bridge glass.
Therefore, it is possible to prevent discharge or short circuit between the pair of internal lead wires. From this, on the contrary, the length of the bridge glass can be shortened, and the bulb diameter can be reduced by reducing the bulb diameter of the portion where the bridge glass is arranged.

According to the second aspect of the present invention, since the anchor is pulled out in the direction intersecting the plane passing through the pair of inner lead wires, the tip of the anchor does not interfere with the inner lead wire or the end portion of the filament. This tip can be easily guided to the middle part of the filament.

According to the invention of claim 3, when the filament is arranged vertically, the bulb can be made thin, but when the bulb is made thin, the length of the bridge glass must be shortened, so that the filament is made vertically. If the configuration described in claim 1 or 2 is adopted in the case of being arranged in the above, these advantages can be effectively utilized.

According to the invention of claim 4, when the valve inner diameter of the portion where the bridge glass is arranged is 6.5 mm or less, the length of the bridge glass is inevitably shortened similarly to the above. Therefore, under such conditions, if the configuration according to any one of claims 1 to 3 is adopted, these advantages can be effectively utilized.

According to the invention of claim 5, if internal lead wires are held at both ends of the bridge glass and the distance between these internal lead wires is set to 2 mm or more, discharge or short circuit between these internal lead wires occurs. Can be prevented.

According to the invention of claim 6, the bulb has a shape of a sphere, an elliptic sphere, or a spherical portion similar thereto, a cylindrical portion continuous with the spherical portion, and a sealing portion, and the filament is accommodated in the spherical portion. In the case of the structure, the bridge glass is housed in the small diameter cylindrical part, and since this part has a small diameter, the length of the bridge glass has to be shortened, and therefore, the valve having such a shape is provided. If the configuration described in claims 1 to 5 is adopted in the case of a light bulb, these advantages can be effectively utilized.

According to the inventions of claims 7 and 8,
It is possible to provide a lighting device and a reflection-type lighting device that take advantage of the advantages of the incandescent light bulb according to the first to sixth aspects.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the first embodiment shown in FIGS. This embodiment shows an example applied to a one-side sealed halogen light bulb and a reflection type lighting device using the same, and FIGS. 1 to 4 are diagrams showing the configuration of a one-side sealed halogen light bulb used as a light source. 5 is a view of a reflection type illumination device.

In the single-sealed halogen light bulb 1 shown in FIGS. 1 to 4, a crushing sealing portion 3 is formed at one end of an arc tube bulb 2 made of quartz glass, and the crushing sealing portion 3 is continuous with the sealing portion 3. A cylindrical portion 4 is formed. Further, an elliptic spherical portion 5 as a spherical portion is formed continuously with the cylindrical portion 4, and the elliptical spherical portion 5 has a major axis extending along the sealing portion 3 and the opposite direction thereof. The direction is the valve center axis O ₁ -O ₁ . The maximum diameter of the elliptical sphere 5 is about 14 mm, and the elliptical shape has a major axis / minor axis ratio of 14/10.
It is set to a degree.

At the other end of the elliptic spherical portion 5, the valve central axis O ₁ −
A thin tube 6 is provided so as to project above O ₁ . This thin tube 6
Utilizes the protrusion that remains after the exhaust pipe is substantially cut off.

A visible light transmitting infrared reflecting film 7 is formed on the outer surface (or inner surface) of the bulb 2. The infrared reflection film 7 is well known and will not be described in detail, but for example, a high refractive index layer formed of an oxide film containing titanium oxide (TiO ₂ ) as a main component and silicon oxide (silica = SiO ₂ ) as a main component. And a low refractive index layer made of an oxide film are alternately laminated to form a multilayer film having a total of 6 to 80 layers.

A filament 8 is accommodated in the bulb 2. The filament 8 is formed of a tungsten wire into a double coil, and its coil axis O ₂ −
O ₂ is arranged to coincide with the valve center line O ₁ -O _1. Further, the filament 8 has a length that substantially extends over the first focal point F ₁ and the second focal point F ₂ of the elliptic spherical portion 5, and the end portion of the filament 8 is located above the focal points F ₁ and F ₂ . Alternatively, it is arranged in the vicinity of the focal point.

The filament 8 is installed between a pair of internal lead wires 10 and 11. These internal lead wires 10 and 11 are connected to metal foil conductors 12 and 13 made of molybdenum Mo or the like whose base ends are sealed in the pressure crushing seal portion 3, and the tip end portions thereof are cylindrical portions of the valve 2. It is led to the elliptical sphere portion 5 through 4.

The pair of internal lead wires 10 and 11 are
The bridge glass 9 is supported in the middle of the cylindrical portion 4. The bridge glass 9 has, for example, an oval shape or a rod shape that extends long in the direction in which the pair of internal lead wires 10 and 11 are arranged, and is arranged in the cylindrical portion 4 so as to intersect the valve axis. The inner diameter d of the cylindrical portion 4 is 6 mm at the maximum, and both longitudinal ends of the bridge glass 9 are separated from the inner surface of the cylindrical portion 4 with a gap of about 1 mm.

The pair of internal lead wires 10 and 11 penetrate the longitudinal ends of the bridge glass 9 and extend to the elliptic spherical portion 5. In this case, a pair of internal lead wires 1
In the portion where 0 and 11 penetrate the bridge glass 9, the separation dimension s of these internal lead wires 10 and 11 is 2 mm or more.

A base end portion of the anchor 12 is fixed through the central portion of the bridge glass 9 in the longitudinal direction. The anchor 12 is made of a high melting point wire such as tungsten or molybdenum, and the root of the bridge glass 9 is bent so as to intersect the bridge glass 9 at a right angle. That is, the anchor 12
The bent portion 12a formed at the root of is bent in a direction perpendicular to the formation surface of the pair of internal lead wires 10 and 11 and the bridge glass 9.

One of the inner lead wires 10 is the elliptic spherical portion 5
The inside extends to the other end side and is inserted into the thin tube 6, and this insertion portion is mechanically locked to the thin tube 6 to be the locking portion 10.
a. The tip of the internal lead wire 10 extends from the engaging portion 10a in the thin tube 6 to the other end side of the filament 8 along the valve center line O ₁ -O ₁ .

The filament 8 has coil-shaped leg portions 8a and 8b at both ends, and these leg portions 8a and 8b are provided.
Are connected to the respective tip portions of the internal lead wires 10 and 11. As a result, the filament 8 is installed between these internal lead wires 10 and 11.

The tip of the wire 12 attached to the center of the bridge glass 9 is the filament 8
Is wound around the central portion of the filament 8 so as to face the central portion of the filament 8. In this case, the winding portion at the tip of the bridge glass 9 is loosely wound around the filament 8.

As shown in FIG. 2, external lead wires 14 and 15 are connected to the metal foil conductors 13 and 13 made of molybdenum Mo or the like, which are sealed in the crushing and sealing portion 3.
The crushing and sealing portion 3 of the valve 2 is covered with an insulating base 16 made of ceramic.
6 is bonded to the crushed and sealed portion 3 with an adhesive 17. The insulating base 16 has a screw-in base 18 and external terminals 19, and the external lead wires 14 and 15 are connected to the screw-in base 18 and external terminals 19.

The halogen bulb 1 having such a structure is shown in FIG.
As shown in (1), it is housed in the reflector 20 corresponding to the main body of the lighting fixture and used as a lighting device. The reflector 20 has a reflector 22 on which a reflecting surface 21 is formed, and a base 23 made of ceramic or the like is joined to the reflector 22. The base 23 is provided with a screw-in portion 24 and an external terminal 25, and is connected to a power source through the screw-in portion 24 and the external terminal 25.

The reflector 22 is made of glass, metal, resin or the like, and the reflecting surface 21 formed on the inner surface thereof may be formed by evaporating aluminum or the like, but it is also possible to form an optical interference film. This light interference film has a function of reflecting visible light but transmitting infrared light, and is a so-called visible light reflecting film. Therefore, the reflector 20 is a dichroic mirror.

In the halogen bulb 1, the screw-in base 18 attached to the insulating base 16 is detachably attached to a socket (not shown) provided in the base 23 of the reflector 20 so that the base 24 and the base 24 of the reflector 20 can be removed. External terminal 2
5 is electrically connected.

The operation of the single-sealed halogen light bulb having such a structure will be described. When a voltage of a power source is applied through the external lead wires 14 and 15, a current flows through the filament 8 and the filament 8 emits light. This light is emitted to the surroundings, passes through the elliptic spherical portion 5 of the bulb 2, and is emitted to the outside. Then, when this light passes through the infrared reflecting film 7 formed on the outer surface of the elliptic spherical portion 5, visible light is transmitted but infrared light is reflected.

The infrared light reflected by the infrared reflecting film 7 is returned to the inside of the bulb 2, and the returned infrared light heats the filament 8. In this case, the filament 8 is arranged so that its coil axis O ₂ -O ₂ coincides with the valve center line O ₁ -O ₁ , so that the infrared rays reflected by the infrared reflecting film 7 are efficiently returned to the filament 8. Be done.

Moreover, since the ends of the filament 8 are located at the elliptical focal points F ₁ and F ₂ , the infrared rays emitted from the first focal point F ₁ return to the second focal point F ₂ and the second focal point F ₂ again.
The infrared rays emitted from the focal point F ₂ of the infrared ray returns to the first focal point F ₁ , and the infrared ray return rate, that is, the recovery rate is increased.

Therefore, the filament 8 is given thermal energy not only by the electric energy supplied from the power source but also by the infrared rays reflected by the infrared reflecting film 7, so that the temperature rise is promoted and the incandescence is promoted. Therefore, if the emission intensity is set to the same level as when the infrared reflection film is not provided, the power energy supplied from the power source is reduced by the amount of heat energy reflected by the infrared reflection film 7 and heating the filament 8. Therefore, power consumption can be saved.

In order to increase the return rate of infrared rays, the surface area of the ellipsoidal sphere 5 is increased by increasing the surface area of the ellipsoidal sphere 5, that is, the inner diameter of the cylindrical portion 4 is decreased. The outer diameter accordingly becomes smaller, and as a result, the halogen bulb 1 having the infrared reflection film 7 can be made smaller than a lamp not having the infrared reflection film 7, and the fixture can be made smaller, and the fixture can be made smaller. There are advantages such as better compatibility with.

When the halogen bulb 1 having the above-mentioned structure is housed in the reflector 20 shown in FIG. 4, the visible light transmitted through the bulb 2 and the infrared reflection film 7 is formed by the visible light reflection film which has an optical interference effect. The light is reflected by the reflecting surface 21 and illuminates the front from the front opening of the reflector 22. In this case, since most of the infrared rays are returned to the inside of the bulb 2 by the infrared reflecting film 7, the proportion of reaching the reflector 22 is small, and the temperature rise of the reflector 22 is prevented. Moreover, infrared rays are transmitted to the wall side of the reflector 22 by the reflecting surface 21 and are reflected by the reflector 2
Infrared rays are not radiated to the front of the reflector 22 because they are released to the back of No. 2, which is effective for radiating visible light that is unfavorable to temperature rise.

Further, according to the above-mentioned reflection type illumination device, the efficiency of the halogen bulb 1 is improved, so that the advantage can be utilized and the illumination device with excellent efficiency is obtained. In the above-described embodiment, the pair of inner lead wires 10 and 11 are supported on the ends of the bridge glass 9, and the anchor 12 is located between the pair of inner lead wires 10 and 11, and the central portion of the bridge glass 9 is located. Therefore, the distance s between the pair of internal lead wires 10 and 11 can be increased. Therefore, it is possible to prevent discharge or short circuit between the pair of internal lead wires 10 and 11.

On the contrary, by supporting the pair of inner lead wires 10 and 11 on the ends of the bridge glass 9, the distance s between the inner lead wires 10 and 11 can be increased. Can be shortened,
The inner diameter d of the bulb at the location where the bridge glass 9 is arranged can be reduced, which is effective for downsizing the light bulb 1.

Especially, the valve inner diameter d of the cylindrical portion 4 is 6.5 mm.
When formed in the following small sizes, the length of the bridge glass 9 can be shortened, so that the bridge glass 9 does not interfere with the bulb wall.

Further, by supporting the pair of internal lead wires 10 and 11 on the ends of the bridge glass 9, the distance between the internal lead wires 10 and 11 can be set to 2 mm or more. It is possible to prevent electric discharge and short circuit between them.

Further, since the anchor 12 is pulled out in the direction intersecting the plane passing through the pair of internal lead wires 10, 11, the tip of the anchor 12 is the internal lead wire 10, 11.
11 and the end portion of the filament 8 can be easily guided to the middle portion of the filament 8 without interfering with the end portion of the filament 8 and the anchor 12 can sufficiently perform its original function of holding the middle portion of the filament 8. it can.

The halogen bulb 1 of the above embodiment has a bulb 2
Since the shape has a structure in which the elliptic spherical portion 5, the cylindrical portion 4 and the sealing portion 3 connected to the elliptic spherical portion 5, and the filament 8 are accommodated in the elliptic spherical portion 5, the bridge glass 9 is attached to the small diameter cylindrical portion 4. Under the condition that it has to be accommodated, and because this part has a small diameter, the length of the bridge glass 9 has to be shortened, and therefore, in the case of the bulb 1 having the bulb 2 of such a shape, A pair of internal leads 10,1
If 1 is supported on the end portion of the bridge glass 9 and the anchor 12 is positioned between the pair of internal lead wires 10 and 11 and held in the central portion of the bridge glass 9, discharge or short circuit occurs. Without shortening the bridge glass 9.

In the above embodiment, the valve shape has the shape having the cylindrical portion 4 and the elliptic spherical portion 5, but the present invention is not limited to this, and the elliptic spherical portion 5 is replaced by a spherical shape. May be.

The present invention is not limited to the electric bulb having the cylindrical portion 4 and the elliptic spherical portion 5, but can be applied to the case of the cylindrical bulb as shown in FIGS. 6 and 7. That is, in FIG. 6, 1 is a cylindrical one-side sealed halogen bulb, and 2
Is a cylindrical bulb made of quartz, 3 is a crushed sealing portion, 7 is an infrared reflecting film, 8 is a filament, 9 is bridge glass,
12 is an anchor wire, 10 and 11 are internal lead wires,
13, 13 are molybdenum foils.

Reference numeral 20 is a reflector, and the front opening is closed by a front glass 30. A mounting cylinder portion 31 is formed on the top of the reflector 20.
The crushable sealing portion 3 of the light bulb 1 is inserted into the, and the sealing portion 3 is fixed to the mounting cylinder portion 31 by the adhesive 33.

Even in the case of such a cylindrical one-side sealed halogen light bulb, when the diameter of the bulb 2 becomes smaller, the bridge glass 9 becomes shorter.
0 and 11 are supported on the ends of the bridge glass 9, and the anchor 12 is fixed to the pair of internal lead wires 10 and 1.
If it is located between the two and is held in the central portion of the bridge glass 9, the internal lead wires 10 and 11 are separated from each other, and no discharge or short circuit occurs. Therefore, the bridge glass 9 can be shortened, and the same effect as the above-mentioned embodiment can be obtained.

[0053]

As described above, according to the invention of claim 1, the pair of inner lead wires are supported by the end portions of the bridge glass and the anchor is held by the central portion of the bridge glass. The distance between the internal lead wires is increased, and it is possible to prevent discharge or short circuit between the internal lead wires. From this, on the contrary, the length of the bridge glass can be shortened, and the bulb diameter can be reduced at the place where the bridge glass is arranged, and the bulb can be miniaturized.

According to the second aspect of the invention, the tip of the anchor can be easily guided to the middle portion of the filament without interfering with the inner lead wire or the end of the filament.

According to the invention of claim 3, when it is applied to a lamp in which the filaments are arranged vertically, it is advantageous for downsizing the bulb. According to the invention of claim 4, since the length of the bridge glass can be shortened when the inner diameter of the bulb at the portion where the bridge glass is arranged is 6.5 mm or less, it is effective for use in such a lamp.

According to the invention of claim 5, since the internal lead wires are fixed to both ends of the bridge glass, the distance between the internal lead wires can be set to 2 mm or more, and discharge or short circuit between the internal lead wires is prevented. can do.

According to the invention of claim 6, the bulb has a shape of a sphere, an elliptic sphere, or a spherical portion similar thereto, a cylindrical portion continuous with the spherical portion, and a sealing portion, and the filament is accommodated in the spherical portion. In the case of the structure, the bridge glass is housed in the cylindrical portion having a small diameter, and since this portion has a small diameter, the length of the bridge glass must be shortened. If the configuration described in claim 5 is adopted, these advantages can be effectively utilized.

According to the inventions of claims 7 and 8,
It is possible to provide a lighting device and a reflection-type lighting device that take advantage of the advantages of the incandescent light bulb according to the first to sixth aspects.

[Brief description of drawings]

FIG. 1 is a perspective view of a halogen bulb having a spherical portion and a cylindrical portion according to the first embodiment of the present invention.

FIG. 2 is a front view of the halogen bulb of the embodiment.

FIG. 3 is a side view of the halogen bulb of the embodiment.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a cross-sectional view of a reflective lighting device using the halogen bulb as a light source.

FIG. 6 is a cross-sectional view of a cylindrical halogen bulb and a reflector incorporating the same according to the second embodiment of the present invention.

FIG. 7 is a perspective view showing the mount of the embodiment.

[Explanation of symbols]

 1 ... Halogen bulb 2 ... Bulb 3 ... Sealing part 4 ... Cylindrical part 5 ... Elliptical sphere part 7 ... Infrared reflecting film 8 ... Filament 9 ... Bridge glass 10, 11 ... Internal lead wire 12 ... Anchor 13 ... Molybdenum foil 20 ... Reflection Body 21 ... Reflective surface 22 ... Reflector

Claims (8)

[Claims] 1. A bulb having a sealing portion formed at one end; a filament housed in the bulb; a pair of internal leads having the other end connected to the filament and one end guided to the sealing portion. A wire; a bridge glass which is provided in the bulb between the sealing portion and the filament and in which the middle portions of the pair of internal lead wires are supported so as to be separated from each other; and one end is between the pair of internal lead wires. An incandescent light bulb, which is positioned and fixed to the bridge glass and has the other end anchored to the middle part of the filament. 2. The incandescent lamp according to claim 1, wherein a direction in which the anchor is led out from the bridge glass is a direction intersecting a surface formed by the pair of internal lead wires and the bridge glass. 3. The incandescent lamp according to claim 1, wherein the filaments are arranged vertically along the bulb axis. 4. The incandescent lamp according to claim 1, wherein an inner diameter of the bulb at a location where the bridge glass is arranged is 6.5 mm or less. 5. The incandescent lamp according to claim 1, wherein a distance between the pair of internal lead wires supported by the bridge glass is 2 mm or more. 6. The bulb has a sphere, an elliptical sphere, or a spherical portion similar to these, a cylindrical portion and a sealing portion which are continuous with the spherical portion, and the filament is housed in the spherical portion, and the cylindrical portion has a cylindrical shape. The incandescent light bulb according to claim 1, wherein the bridge glass is housed. 7. An illuminating device, comprising: the incandescent lamp according to claim 1; and a luminaire in which the incandescent lamp is incorporated. 8. The lighting device according to claim 7, wherein the lighting fixture includes a reflector that reflects light emitted from the incandescent lamp.