JPH0969357A - Incandescent light bulb and reflective lighting device using the same - Google Patents

Abstract

(57) Abstract: An incandescent lamp capable of preventing the filament from coming into contact with the inner surface of the bulb even if the anchor is eliminated, and a reflective lighting device using the same. A filament (8) is accommodated in a bulb (2) having a sealing portion (3) formed at one end along the valve axial direction, and the filament (8) is led from the sealing portion (3) to form a pair of lead wires (10, 11). When the distance from one of the lead wires in the central portion of the filament is A and the inner diameter of the bulb in the central portion of the filament is D, A ≦ 0.55D. Even if the filament resonates, the amplitude will not increase further when the filament contacts the lead wire, so that the filament will not contact the inner surface of the valve and the filament will contact the valve without using the anchor. Can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incandescent lamp in which a bulb containing a filament is supported without using an anchor, and a reflection type illumination device using the same.

[0002]

2. Description of the Related Art In incandescent light bulbs including halogen light bulbs,
A one-sealing type bulb in which filaments are arranged in the longitudinal direction, that is, a filament axis is arranged along the valve axis direction (CC-8 type) is a pair of filaments guided from the sealing portion. It is supported by lead wires. That is, one lead wire guided from the sealing portion extends into the bulb, extends along the filament to the other end of the bulb, and one end of the filament is connected to this tip, and the other lead. A wire extends from the seal into the bulb and is joined at its tip to the other end of the filament.

An incandescent light bulb provided with such a CC-8 type filament is liable to be damaged if the filament in a high temperature state shakes and comes into contact with the inner surface of the bulb if shock or vibration is applied during lighting. There is. In order to prevent this, conventionally, an approximately central portion of the filament has been supported by an anchor.

The anchor is planted in a bridge glass housed at the end of the bulb near the sealing portion, and the pair of lead wires are also held through the bridge glass.

[0005]

However, recently,
There is a demand to facilitate focus adjustment when an incandescent light bulb is brought close to a point light source and incorporated into a reflector,
In addition, there is a strong demand for cost reductions, and for this reason miniaturization is being promoted. For example, a concrete plan for making the inner diameter of the elliptical valve 15 mm or less is being studied.

However, when the bulb is downsized, the bulb diameter at the portion where the bridge glass is housed is also reduced,
Therefore, the length of the bridge glass is restricted. When a pair of internal lead wires and anchors are attached to such a bridge glass, since the length is short, the pair of lead wires and anchors come close to each other, and the creepage distance becomes short, so that they are electrically connected to each other or discharge is generated. I'm worried. For this reason, there has been a demand that the use of anchors be abolished, the bridge glass is abolished, or the bridge glass is shortened.

However, if the anchor is abolished, as described above, if shock or vibration is applied during lighting, there is a concern that the filament will shake and come into contact with the inner surface of the bulb, resulting in damage to the bulb. In particular, when the filament is formed of a double coil or a triple coil, there is a problem that the central portion of the filament has a large amplitude, so that if the valve is made small, the filament is swayed and it is easy to contact the inner surface of the valve.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an incandescent light bulb which can prevent the filament from coming into contact with the inner surface of the bulb even if the anchor is abolished. The present invention aims to provide a conventional reflective lighting device.

[0009]

[Means for Solving the Problems]

[Structure] The invention according to claim 1 is a valve having a sealed portion formed at one end; a filament which is housed in the valve and which is composed of a double coil or a triple coil and whose coil axis is arranged along the valve axis; One lead wire extending from the sealing portion into the bulb, extending along the filament to the other end of the bulb and connected to the other end of the filament; extending from the sealing portion into the bulb, the filament And the other lead wire connected to one end of the filament; and A is the distance between the filament and the one lead wire in the central portion of the filament, and D is the valve inner diameter in the central portion of the filament. , A ≦ 0.55D
It is an incandescent light bulb characterized in that.

The invention of claim 2 is the incandescent lamp according to claim 1, characterized in that the filament length CL is 8 mm or more. The invention according to claim 3 is the incandescent light bulb according to claim 1 or 2, wherein the maximum inner diameter D of the bulb in the central portion of the filament is 15 mm or less.

The invention according to claim 4 is the incandescent lamp according to any one of claims 1 to 3, characterized in that the bulb has a cylindrical shape. A fifth aspect of the present invention is the incandescent light bulb according to any one of the first to third aspects, wherein the bulb has an elliptic spherical shape in a portion where the filament is accommodated.

The invention of claim 6 is the filament length C
L is 8 mm or more and 12 mm or less, the weight MG per 20 cm of the tungsten wire constituting the filament is 15 mg or less, and the maximum color temperature of the filament during lighting is 260.
It is 0K or more and 3100K or less, and the relationship between A and D is
The incandescent lamp according to any one of claims 1 to 5, wherein A? 0.46D.

According to a seventh aspect of the present invention, the inner diameter of the bulb end portion connected to the sealing portion is 8 mm or less, and a bridge glass holding a pair of lead wires is provided at the bulb end portion. The incandescent light bulb according to any one of claims 1 to 6.

The invention according to claim 8 comprises the incandescent lamp according to any one of claims 1 to 7; and a reflector incorporating the incandescent lamp; It is a device.

The incandescent light bulb of the present invention includes a halogen light bulb and may or may not have a multilayer interference film such as an infrared reflection film formed on the surface of the bulb.

[Operation] According to the invention of claim 1, the following operation is achieved. That is, the filament resonates when a shock or vibration is applied to the bulb. According to experiments conducted by the present inventors, it was found that the central portion of the filament resonates not only in the Y direction but also in the X direction even when vibration is applied in the Y direction shown in FIG. . However, in this case, the amplitude in the X direction is smaller than the amplitude in the Y direction, and the central portion of the filament resonates within the elliptical (ellipsoidal) region as shown in the figure.

In such a resonance movement, when the filament comes into contact with one of the lead wires arranged along the same, resonance in the X direction is suppressed by this lead wire, and therefore vibration in the Y direction is caused. Also becomes restricted within an elliptical (ellipse) shaped area corresponding to this. If the filament is restricted from vibrating in the Y direction, it will not contact the inner surface of the valve, that is, if the filament contacts one lead wire, its resonance will be suppressed and it will not contact the inner surface of the valve. Was given.

From the above, the present inventors have conducted experiments,
As a result of repeated studies, when the distance between this filament and one lead wire in the central portion of the filament is A and the valve inner diameter in the central portion of the filament is D, an anchor is used as in the invention of claim 1. It was found that the filament could be prevented from contacting the bulb without doing so.

According to the invention of claim 2, the amplitude of the central portion becomes large when the length CL of the filament is 8 mm or more, but if the condition of A ≦ 0.55D shown in claim 1 is satisfied, the filament is Can be reliably prevented from coming into contact with the valve.

According to the invention of claim 3, in the case of an incandescent lamp in which the maximum inner diameter D of the bulb in the central portion of the filament is 15 mm or less, the distance between the filament and the bulb becomes close and the filament easily contacts the bulb. However, if the condition of claim 1 is satisfied, it is possible to prevent filament contact even with a small bulb having a maximum inner diameter D of 15 mm or less.

According to the invention of claim 4, when the bulb is cylindrical, the maximum inner diameter of the bulb in the central portion of the filament tends to be small, and in such a case, the distance between the filament and the bulb is close. Then, the filament easily contacts the bulb. However, if the condition of claim 1 is satisfied, the filament can be prevented from coming into contact with the cylindrical bulb.

According to the fifth aspect of the invention, when the bulb shape is an ellipsoidal shape where the filament is accommodated, the distance between the filament and the bulb becomes relatively large, so that the filament is less likely to come into contact with the bulb. And further prevent contact.

According to the invention of claim 6, the length CL of the filament is not less than 8 mm and not more than 12 mm, and the weight MG per 20 cm of the tungsten element wire constituting the filament is 1.
For small incandescent lamps with a maximum color temperature of 5 mg or less and the maximum color temperature of the filament being lit is 2600 K or more and 3100 K or less, if the relationship between A and D is A ≤ 0.46 D, the filament is prevented from coming into contact with the bulb. be able to.

According to the invention of claim 7, when the inner diameter of the valve end portion continuous with the sealing portion is 8 mm or less, the length of the bridge glass must be shortened, and the anchor cannot be used. If the conditions of the above claims are satisfied, it is possible to prevent the filament from coming into contact with the bulb without using an anchor. According to the invention of claim 8, it is possible to provide a reflection type illumination device that can utilize the advantages of the incandescent lamp according to any one of claims 1 to 7.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to 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 characteristic diagram, and FIG. 6 is a diagram of a reflective 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 having an inner diameter of 8 mm or less is formed, and an elliptic spherical portion 5 as a spherical portion is formed continuously with the cylindrical portion 4. The elliptic spherical portion 5 has a major axis extending along the sealing portion 3 and the opposite direction thereof, and the major axis direction is the valve center axis O ₁ -O ₁ . The elliptical shape of the elliptical spherical portion 5 is set such that the major axis / minor axis ratio is about 20/14, and the maximum inner diameter D of the elliptical spherical portion 5 is 15 mm or less.

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. As shown in FIG. 3, the infrared reflective film 7 is configured by alternately forming high refractive index layers 71 ... Low refractive index layers 72 ... As a multilayer film of 6 to 80 layers in total, for example. Has a laminated structure of 34 layers in total. Such an infrared reflection film 7 has a function of reflecting infrared rays by a multilayer interference effect, but transmitting visible light. The high refractive index layers 71 ...
The main component is titanium oxide (TiO ₂ ), and the low refractive index layers 72 are made of silicon oxide (silica = S
iO ₂ ) is the main component.

A filament 8 is housed in the bulb 2. The filament 8 is formed of a tungsten wire into a double coil or a triple coil (double coil in this example), and its coil axis O ₂ -O ₂
Are arranged so as to coincide with the valve center line O ₁ -O ₁ . The filament 8 has a length CL of 8 mm or more, for example, 8 mm to 12 mm, and 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. , The ends of the filament 8 have these focal points F ₁ and F ₂
It is designed to be placed on or near the focal point.

In this case, the filament 8 has a weight MG of 5 mg to 20 mg per 20 cm of the tungsten wire. 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 4 of the valve 2. It is guided to the elliptical sphere portion 5 through. The pair of internal lead wires 10 and 11 are connected to each other by a bridge glass 9 in the cylindrical portion 4 in the middle thereof, whereby the internal lead wires 10 and 11 are kept at a mutual interval.

The bridge glass 9 has a rod shape extending in the direction in which the pair of internal lead wires 10 and 11 are arranged, and is arranged in the cylindrical portion 4. The middle of the pair of inner lead wires 10 and 11 penetrates the bridge glass 9 and extends to the elliptical sphere portion 5, and one inner lead wire 10 extends in the elliptical sphere portion 5 along the filament 8 to the other end side. It is growing. A tip portion of the internal lead wire 10 is inserted into the thin tube 6, and the inserted portion is mechanically locked to the thin tube 6 to form a locking portion 10a. 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 other inner lead wire 11 extends through the bridge glass 9 into the ellipsoidal sphere portion 5 and is guided to one end side of the filament 8 along the bulb 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.

In such an arrangement, the filament 8
The distance A between the one inner lead wires 10 led to the other end of the bulb 2 along the line is set so as to satisfy the relationship shown in FIG. That is, the interval A between the center of the filament 8 and the center of the internal lead wire 10
Is the inner diameter of the valve at this point (corresponding to the maximum inner diameter of the valve)
The relationship with D is A ≦ 0.55D (1).

In particular, the length CL of the filament 8 is not less than 8 mm and not more than 12 mm, the weight MG per 20 cm of the tungsten wire constituting the filament 8 is not more than 15 mg, and the maximum color temperature of the filament during lighting is 2600
In the case of K or more and 3100K or less, A ≦ 0.46D (2).

Molybdenum Mo sealed in the crushing seal portion 3
External lead wires 14 and 15 are connected to the metal foil conductors 12 and 13 made of, for example, as shown in FIG. The crushing sealing portion 3 of the valve 2 is made of a ceramic insulating base 16
, And the insulating base 16 is
Are bonded by an adhesive 17. The insulating base 16 has a screw-in base 18 and an external terminal 19, and the external lead wires 14 and 15 are connected to the screw-in base 18 and the external terminal 19.

The halogen bulb 1 having such a structure is shown in FIG.
As shown in FIG. The reflector 20 shown in FIG. 6 has a reflector 22 having a reflecting surface 21 formed thereon. The reflector 22 is made of glass, metal,
The reflecting surface 21 made of a resin or the like and formed on the inner surface thereof may be formed by evaporating aluminum or the like. However, a visible light is formed by a multilayer interference film in which high refractive index layers and low refractive index layers are alternately laminated. However, it may be formed of a visible light reflecting film which reflects infrared rays but transmits infrared rays. Such a reflector 2
An insulating base 23 made of ceramic or the like is bonded to the element 2. A socket 24 is attached to the insulating base 23, and the screw-in base 18 of the halogen bulb 1 is detachably attached to the socket 24, and is housed in the reflector 20. . A screw-type base 25 and an external terminal 26 are provided at the end of the insulating base 23.
And the external terminal 26 is adapted to be connected to a power source. Therefore, the halogen bulb 1 is connected to the insulating base 23
When attached to the socket 24, the halogen bulb 1 is connected to the power source through the base 25 and the external terminal 26.

The operation of the single-sealed halogen light bulb having such a structure will be described. When a power supply voltage is applied to 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, since the filament 8 is arranged so that its coil axis O ₂ -O ₂ coincides with the valve center line O ₁ -O ₁ , the infrared rays reflected by the infrared reflection film 7 are efficiently returned to the filament 8. is, moreover, in the present embodiment, the filament 8, the first focus F ₁ and a second focal point F ₂ of the valve 2 forming an ellipse spherical having a straddle length, the ends of these focal point F is disposed over the _first and F _2, the infrared rays emitted from the first focal point F ₁ is returned to the focal point F ₂ of the second, also infrared emitted from the second focal point F ₂ is the first focus F ₁ Since it returns to, the return rate of infrared rays, that is, the recovery rate becomes high.

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. ,
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 supply can be reduced by the amount of the heat energy reflected by the infrared reflection film 7 and heating the filament 8. It is possible to save power consumption.

When the halogen bulb 1 having the above structure is housed in the reflector 20 shown in FIG. 5, the visible light transmitted through the bulb 2 and the infrared reflecting film 7 is reflected by the reflecting surface 21, and the front opening of the reflector 22. Irradiate from the front.

According to such a reflection type illuminating device, the efficiency of the halogen bulb 1 is improved, so that the advantage can be utilized and the illuminating device having excellent efficiency can be obtained. Further, in the present embodiment, as shown in FIG. 4, the distance A between the central portion of the filament 8 and the one inner lead wire 10 guided to the other end of the bulb 2 along the filament 8 is the inner diameter of the bulb at this location. If (corresponding to the maximum inner diameter of the valve) is D, then A ≦ 0.55D (1).

That is, when shock or vibration is applied to the valve 2, the filament 8 resonates, and even if vibration is applied only in the Y direction in FIG. 4, the central portion of the filament 8 resonates not only in the Y direction but also in the X direction. To do. However, the amplitude in the X direction is smaller than the amplitude in the Y direction, and the central portion of the filament vibrates in an elliptical (elliptical) shape as shown in the figure. In such a resonant movement, when the filament 8 contacts one of the lead wires 10 arranged along it, the filament 8
This lead wire 10 suppresses resonance in the X direction, and at the same time regulates vibration in the Y direction. Therefore, when the filament 8 comes into contact with one of the lead wires 10 and the resonance is suppressed, the filament 8 may not come into contact with the inner surface of the bulb 2. For this purpose, the central portion of the filament 8 and the one lead wire 10 may be made. It has been found that it is sufficient to regulate the interval A between and.

The above formula (1) has been confirmed by experiments by the present inventors. To explain this, whether the filament 8 contacts the bulb 2 when the filament 8 is vibrated in the Y direction. Can be estimated by considering the filament 8 as a spring and examining its spring characteristics.
The spring characteristics of the double coil are the elastic modulus of the material (tungsten), the filament length CL, the weight MG (mg) per 20 cm of the tungsten element wire, the core wire diameter of the primary winding, and the 2
Core wire diameter of secondary winding, number of turns of secondary winding,% pitch of primary winding (= coil pitch of primary winding / wire diameter × 100),% pitch of secondary winding (= secondary winding It is determined by the coil pitch of the wire / the outer diameter of the primary winding × 100) and the filament temperature during lighting.

When the factors affecting the amplitude were investigated by changing these conditions variously, the inventors found that the filament material is usually tungsten, so that the elastic modulus does not change, and that this type of small halogen bulb is used. In the case of, the core wire diameter of the primary winding = 0.2 to 0.4 mm, the core wire diameter of the secondary winding = 0.7 to
1.0 mm, number of turns of secondary winding = 6 to 13 turns,% pitch of primary winding = 150 to 250,% pitch of secondary winding = 1
It was confirmed that the range was 20 to 300, and these changes had little or no effect on the amplitude.

The factors that affect the amplitude are the filament length CL and the tungsten filaments that compose the filament.
It was found that the weight per 0 cm was MG, and the maximum color temperature of the filament during lighting.

The filament temperature of this kind of light bulb is 2600
Since it is K or more and 3100 K or less, various tests were conducted on the relationship between the A / D relationship and the filament valve contact rate% in this range, and the characteristic diagram shown in FIG. 5 was obtained.

In FIG. 5, the characteristic a is CL = 8 to 12 m.
m, MG = 5 mg, and the characteristic b is CL = 8 to 12 m
This is the case when m and MG = 20 mg. From the characteristics of this, A /
It has been found that if D is 0.55 or less, the bulb contact ratio of the filament can be suppressed.

From the characteristic a in particular, the length C of the filament 8 is
L is 8 mm or more and 12 mm or less, and the weight MG per 20 cm of the tungsten wire constituting the filament 8 is 15 mg.
If the maximum color temperature of the filament being turned on is 2600 K or more and 3100 K or less, it is understood that the range of A ≦ 0.46D (2) is good.

From the above, if the above expression (1) is satisfied, even if the filament 8 resonates, the filament 8 comes into contact with one of the lead wires 10 to cause a further amplitude in the X direction. Growth is prevented, and as a result, vibration in the Y direction is suppressed, and
Will be prevented from touching. In particular, the case where the above (2) is satisfied is particularly preferable.

Therefore, with such a light bulb, the filament is prevented from coming into contact with the bulb without the use of an anchor. Therefore, the bulb diameter can be reduced by the amount without the use of an anchor, and the bridge glass can be used. The length of 9 can be reduced.

In the above embodiment, the case where the valve shape is the shape having the cylindrical portion 5 and the elliptic spherical portion 5 has been described, but the present invention is not limited to this, and a cylindrical valve as shown in FIG. 7 is used. It can be implemented even in the case. That is, in FIG. 7, 2 is a cylindrical valve made of quartz, 3
Is a crushed seal portion, 7 is an infrared reflection film, 8 is a filament,
9 is bridge glass, 10 and 11 are internal lead wires, 1
Reference numerals 2 and 13 are molybdenum foils, 16 is an insulating base, 18 is a screw-type base, and 19 is a terminal. Even in the case of such a cylindrical one-side sealed halogen bulb, if the conditions of the present invention are satisfied, it is possible to prevent the filament 8 from coming into contact with the bulb 2 without using an anchor.
It is possible to prevent damage to the valve and reduce the valve diameter.

[0052]

As described above, according to the first aspect of the present invention, even if the filament resonates, if the filament comes into contact with the lead wire, the increase in the amplitude is further restricted. It will not contact the inner surface, thus preventing the filament from contacting the bulb without the use of anchors. From such a thing,
The valve diameter can be reduced.

According to the second aspect of the present invention, when the length CL of the filament is 8 mm or more, the amplitude of the central portion becomes large, but if the condition of A ≦ 0.55D is satisfied, the filament contacts the bulb. Can be reliably prevented.

According to the third aspect of the invention, in the case of an incandescent light bulb in which the maximum inner diameter D of the bulb in the central portion of the filament is 15 mm or less, the filament and the bulb are close to each other, and the filament easily contacts the bulb. However, if the condition of claim 1 is satisfied, it is possible to prevent filament contact even with a small bulb having a maximum inner diameter D of 15 mm or less.

According to the fourth aspect of the invention, when the shape of the bulb is cylindrical, the maximum inner diameter of the bulb in the central portion of the filament tends to be small, and in such a case, the distance between the filament and the bulb is short. Then, the filament easily contacts the bulb. However, if the condition of claim 1 is satisfied, the filament can be prevented from coming into contact with the cylindrical bulb.

According to the fifth aspect of the invention, when the bulb shape is an elliptical sphere at the location where the filament is housed, the distance between the filament and the bulb becomes relatively large, so that the filament is less likely to come into contact with the bulb. And further prevent contact.

According to the invention of claim 6, the length CL of the filament is 8 mm or more and 12 mm or less, and the weight MG per 20 cm of the tungsten wire constituting the filament is 1 mm.
In a small incandescent light bulb with a maximum color temperature of 5 mg or less and the maximum color temperature of the filament being lit is 2600 K or more and 3100 K or less, if the relationship between A and D is A ≦ 0.46D, the filament is prevented from coming into contact with the bulb. It

According to the invention of claim 7, when the inner diameter of the valve end portion continuous with the sealing portion is 8 mm or less, the length of the bridge glass must be shortened, and the anchor cannot be used. If the conditions of the above claims are satisfied, it is possible to prevent the filament from coming into contact with the bulb without using an anchor. According to the invention of claim 8, it is possible to provide a reflection type illumination device that can utilize the advantages of the incandescent lamp according to any one of claims 1 to 7.

[Brief description of drawings]

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

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

FIG. 3 is a cross-sectional view schematically showing the structure of a multilayer interference film that constitutes an infrared reflective film.

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

FIG. 5 is a characteristic diagram showing the relationship between the distance between the filament and the lead wire and the valve contact rate of the filament.

FIG. 6 is a cross-sectional view of a reflective lighting device using the halogen bulb shown in FIGS. 1 to 4 as a light source.

FIG. 7 is a front view of a cylindrical halogen bulb according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Halogen bulb 2 ... Bulb 3 ... Sealing part 4 ... Cylindrical part 5 ... Elliptical sphere part 6 ... Capillary tube 7 ... Infrared reflecting film 8 ... Filament 9 ... Bridge glass 10, 11 ... Internal lead wire 20 ... Reflector 21 ... Reflection Surface 22 ... Reflector

Claims (8)

[Claims] 1. A valve having a sealing portion formed at one end; a filament which is housed in the valve and has a coil axis arranged along the valve axis and which is composed of a double coil or a triple coil; One lead wire extending into the bulb and extending to the other end of the bulb along the filament and connected to the other end of the filament; extending from the sealing portion into the bulb, and joining to one end of the filament If the distance between the filament and the one lead wire in the central portion of the filament is A and the valve inner diameter in the central portion of the filament is D, then A ≦ 0. An incandescent light bulb characterized by being 55D. 2. The incandescent lamp according to claim 1, wherein the filament length CL is 8 mm or more. 3. The incandescent lamp according to claim 1, wherein the maximum inner diameter D of the bulb in the central portion of the filament is 15 mm or less. 4. The incandescent lamp according to claim 1, wherein the bulb has a cylindrical shape. 5. The incandescent lamp according to claim 1, wherein the bulb has a shape of an ellipsoidal sphere where the filament is accommodated. 6. The filament length CL is 8 mm or more 12
mm or less, the weight MG per 20 cm of the tungsten element wire constituting the filament is 15 mg or less, and the maximum color temperature of the filament during lighting is 2600 K or more and 3100 or more.
The incandescent light bulb according to any one of claims 1 to 5, which is K or less and the relation between A and D is A ≤ 0.46D. 7. The inner diameter of the valve end portion connected to the sealing portion is 8
The incandescent lamp according to any one of claims 1 to 6, wherein the bulb glass has a length of less than or equal to mm and a bridge glass holding a pair of lead wires is provided at an end portion of the bulb. 8. A reflective lighting device comprising: the incandescent lamp according to claim 1; and a reflector incorporating the incandescent lamp.