JPH08273629A - Incandescent electric bulb and reflection type lighting system - Google Patents

Abstract

PURPOSE: To provide an incandescent electric bulb and reflection type lighting system which is prevented before from being broken and provide a reflection type lighting system by preventing discharge from spreading to a sealing part even if the discharge is generated due to rupture of a filament in a terminal stage of the life. CONSTITUTION: An incandescent lamp has characteristics that a filament 8 is housed in a bulb 2 in one end of which a sealing part 3 is formed, a shielding member 9 is installed between the sealing part and the filament, and that the maximum inner diameter (a) of a part of the bulb at which the shielding member 9 is positioned and the minimum width (b) of the shielding member are so determined as to have a relation; a <=2.5b. Consequently, since the bulb becomes relatively thinner, the expansion of an arc is shielded by the bulb wall and the growth of the arc is thus limited even in the case the arc is going to expand into an arc-like shape. Moreover, a gap between the part with the minimum width of the shielding member and the inner face of the bulb becomes narrow and discharge is suppressed from expanding to the sealing part by the shielding member.

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 reflective illuminator using the same.

[0002]

2. Description of the Related Art A single-sealed halogen light bulb has a crushed and sealed structure formed at one end of a bulb made of quartz, and the filament contained in the bulb is sealed by a lead wire. It is connected to a metal foil conductor such as molybdenum sealed to the part.

When the filament is broken at the end of its life, discharge may occur between the legs of the broken filament or between the ends of the lead wires connected to these legs. When such a discharge occurs, a large current flows, so the fuse inserted in the power supply circuit is usually blown to cut off the power supply to the lamp and turn it off.

[0004]

However, in rare cases, the above-mentioned discharge is caused between one of the blown filaments and the connection point between the other lead wire and the molybdenum foil which are electrically opposite in potential to the filament. It may occur in the meantime.
That is, an arc of discharge may be generated by extending between the filament and the sealing portion. In such a case, the sealing portion is overheated and softened, which may cause damage to the bulb.

Japanese Unexamined Patent Publication (Kokai) No. 54-82879 discloses a single-sealed incandescent lamp in which an insulating shield member is provided in the bulb between the filament and the sealing portion.
Such an insulating shielding member has an effect of suppressing the heat of the filament from being transferred to the sealing portion, but since the arc of the discharge extends in an arc shape, it bypasses the outside of the insulating shielding member and reaches the sealing portion. Therefore, there is a problem that it is not possible to prevent damage to the sealing portion due to undesired discharge when the filament is blown at the end of its life, only by the means disclosed in the above publication.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent the discharge from extending to the sealing portion when the discharge is generated due to the disconnection of the filament at the end of life. It is intended to provide an incandescent light bulb and a reflection type lighting device capable of preventing the bulb from being damaged.

[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; and a valve between the sealing portion and the filament. A shielding member provided; and, when the maximum inner diameter of the portion of the valve where the shielding member is located is a and the minimum width of the shielding member is b, then a ≦ 2.5b. It is an incandescent light bulb.

The invention according to claim 2 is the incandescent lamp according to claim 1, characterized in that the shielding member is made of bead glass supported by lead wires. According to a third aspect of the present invention, a valve has a spherical portion, an elliptic spherical portion, or a spherical portion having a shape similar to these, a cylindrical portion continuous with the spherical portion, and a sealing portion, and the filament is accommodated in the spherical portion and the cylindrical portion. The incandescent light bulb according to claim 1 or 2, wherein a shield member is housed in the portion.

The invention of claim 4 is characterized in that the bulb is provided with an infrared reflecting film for transmitting visible light on either the inside or outside surface thereof. It is the described incandescent light bulb.

The invention according to claim 5 is characterized in that an extension line of a line connecting one end of the filament and the outer edge of the minimum width portion of the shielding member passes through the outside of the sealing portion. The incandescent lamp according to any one of 4 above.

The invention of claim 6 comprises the incandescent lamp according to any one of claims 1 to 5; and a reflector incorporating the incandescent lamp; It is a device.

[0012]

According to the invention of claim 1, the relationship between the maximum inner diameter a of the portion of the valve where the shielding member is located and the minimum width b of the shielding member is set to a≤2.5b. Therefore, the filament breaks at the end of its life. Thus, even if a discharge is generated, this discharge is prevented from extending to the sealing portion. That is, in the case of a> 2.5b, since the bulb becomes relatively thick, the arc easily grows in an arc shape, and a large gap is generated between the outer surface having the minimum width of the shielding member and the inner surface of the valve. The above arc extending in an arc shape bypasses the shielding member and extends to the sealing portion. However, if a ≦ 2.5b, the bulb becomes relatively thin, so that the arc tries to grow in an arc shape. The bulge of the arc is blocked by the bulb wall, so that the growth of the arc is restricted and the expansion of the arc is suppressed. Moreover, a narrow gap is formed between the outer surface of the shield member having the minimum width and the inner surface of the bulb at this position, and this gap prevents the discharge from passing to the sealing portion. Therefore, damage to the sealing portion is prevented.

According to the second aspect of the present invention, since the shielding member is made of bead glass supported by the lead wires, the supporting structure of the shielding member is simple and the distance between the pair of lead wires is small. To keep it constant.

According to the third aspect of the invention, since the filament is housed in the spherical portion and the shielding member is housed in the cylindrical portion, it is difficult for the discharge to reach the sealing portion side. That is, since the cylindrical portion is formed thinner than the spherical portion, when the shielding member is housed in the cylindrical portion, a narrower gap is formed between the outer periphery of the shielding member and the inner surface of the cylindrical portion, which makes it difficult for the discharge to pass. Become.

According to the invention of claim 4, since the infrared reflecting film for transmitting visible light is provided on either the inside or the outside of the bulb, the infrared rays emitted from the filament are reflected by the infrared reflecting film and the filament is reflected. The efficiency is improved because the filament is heated again. Then, during normal lighting, the heat of the filament is blocked by the shielding member, and it becomes difficult for the heat to reach the sealing portion, and the temperature rise of the sealing portion can be prevented.

According to the fifth aspect of the invention, the filament and the sealing portion sandwich the shielding member and are shaded from each other, so that the heat of the filament is shielded by the shielding member during lighting and it is difficult to reach the sealing portion. Therefore, the temperature rise of the sealing portion can be prevented more reliably. According to the invention of claim 6, it is possible to provide a reflection type illumination device that makes the most of the advantages of the incandescent lamps of claims 1 to 5.

[0017]

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 3 are views showing the configuration of a one-side sealed halogen light bulb used as a light source. 4 is a diagram for explaining the operation, and FIG. 5 is a diagram of the reflection type illumination device.

The single-sealed halogen light bulb 1 shown in FIGS. 1 to 3 has a crushed sealing portion 3 formed at one end of an arc tube bulb 2 made of quartz glass, and is continuous with the sealing portion 3. A cylindrical portion 4 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 sphere 5 is set such that the ratio of the major axis / minor axis is about 14/10.

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. Then, the laminated structure has a total of 33 layers. 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, 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 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 in the middle of the cylindrical portion 4 by a bead glass 9 corresponding to the shielding member of the present invention.
As a result, the internal lead wires 10 and 11 are kept spaced from each other.

The bead glass 9 is, for example, in the shape of an ellipse or a rod that extends long in the direction in which the pair of inner lead wires 10 and 11 are arranged, and is arranged in the cylindrical portion 4. The outer peripheral surface of the bead glass 9 is close to the inner peripheral surface of the cylindrical portion 4, the minimum width of the bead glass 9 is b, and the maximum inner diameter of the bulb 2 at the position where the bead glass 9 is located,
In the case of the present example, when the maximum inner diameter of the cylindrical portion 4 is a, the relationship of a ≦ 2.5b is established. By the way, the maximum inner diameter a of the bulb 2 is 10 mm, and the minimum width b of the bead glass 9 is
Is 4.8 mm, and a = 2.1b.

Further, since the bead glass 9 is provided between the filament 8 and the sealing portion 3, the filament 8 and the sealing portion 3 are arranged so as to be shaded with each other with the bead glass 9 interposed therebetween. ing. That is, the extension line L connecting the end of the filament 8 and the outer edge of the bead glass 9 is
It passes through the outside of the sealing portion 3, in other words, the sealing portion 3 exists in the expansion angle θ of the outer edge of the bead glass 9 when the bead glass 9 is exposed from the end of the filament 8. It is like this.

The middle of the pair of internal lead wires 10 and 11 penetrates the bead glass 9 and extends to the elliptic spherical portion 5,
One of the inner lead wires 10 extends into the other end of the ellipsoidal sphere 5 and 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 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.

As shown in FIG. 2, external lead wires 14 and 15 are connected to the metal foil conductors 12 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 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 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 base 24 and an external terminal 25, and is connected to a power source through the screw-in base 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 of the reflector 22 may be formed by evaporating aluminum or the like, but may be formed by the optical interference film of the present invention. it can. Although not shown, the light interference film in this case is similar to the case of FIG. 3 and is configured by alternately stacking high refractive index layers and low refractive index layers, and the visible light is generated by the multilayer interference action of these layers. However, it is a so-called visible light reflecting film that has the function of reflecting infrared rays and transmitting infrared rays. 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 of the reflector 20 and 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 rays reflected by the infrared reflecting film 7 are returned to the inside of the bulb 2 and the returned infrared rays heat 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. Be done.

Moreover, in the case of this embodiment, the filament 8
Is the focal point F ₂ a first focal point F ₁ and the second valve 2 forming an ellipse spherical having a straddle too wide, ends disposed on these focus F ₁ and F ₂ Therefore, the infrared rays emitted from the first focus F ₁ return to the second focus F ₂ ,
Further, since the infrared rays emitted from the second focus F ₂ return to the first focus F ₁ , the infrared ray return rate, 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. 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.

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 reflecting film 7 is formed by the visible light reflecting film having a light 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. When the reflecting surface 21 of the reflector 22 is coated with a visible light reflecting infrared ray transmitting film to form a dichroic mirror,
The temperature rise of the irradiation surface can be further suppressed.

In the above embodiment, the maximum inner diameter of the bulb 2 where the shielding member is located, that is, the maximum inner diameter of the cylindrical portion 4 is a, and the minimum width of the bead glass 9 corresponding to the shielding member is b. , A ≦ 2.5b, even if the filament 8 is broken at the end of its life and a discharge is generated, this discharge is prevented from extending to the sealing portion 3. When the filament 8 is broken at the end of its life, discharge may occur between the current-carrying members divided by these breaks. Normally,
As indicated by A, the legs 8a and 8b of the filament 8 are
The arc flies between the inner lead wires 10 and 11 near the leg portions 8a and 8b. In this case, since a large current flows, the fuse of the power supply circuit is blown and the power supply circuit is cut off.

However, although it is rare, the arc extends, and as shown in FIG. 4B, one leg 8a of the filament 8 is formed.
Or one of the inner lead wires 10 close to this and the sealing portion 3
An arc may occur between the other lead wire 11 and the connection portion of the molybdenum foil 13. In such a case, it is desired that the bead glass 9 shields the arc from expanding and prevents the arc spot from being generated in the sealing portion 3. Therefore, the elongation of the arc was prevented by setting a ≦ 2.5b. That is, when the maximum inner diameter a of the bulb in the bead glass 9 portion is a> 2.5b, the cylindrical portion 4 becomes thick and the arc easily draws an arc, and in addition, the outer surface of the minimum width portion of the bead glass 9 and the cylindrical portion A large gap is generated between the inner surface of the portion 4 and the arc extending in an arc shape, bypassing the bead glass 9 and extending to the sealing portion 3. On the other hand, if a ≦ 2.5b, since the cylindrical portion 4 becomes thin, even if the arc tries to grow in an arc shape, its bulge is blocked by the valve wall and the growth is restricted, and the arc elongation is suppressed. It Moreover, the outer surface of the minimum width portion of the bead glass 9 and the cylindrical portion 4
There is a narrow gap between the bead glass 9 and
By this, the passage of the discharge is regulated. Therefore, no arc spot is generated in the sealing portion 3, and the sealing portion 3 is prevented from being damaged.

The following Table 1 shows the maximum inner diameter of the elliptical sphere 5 as a,
When the minimum width of the bead glass 9 is set to b, these dimensions are variously changed, and data showing the results of examining the rate of damage occurring in the sealing portion 3 are shown.

[0040]

[Table 1]

From the experimental results shown in Table 1 above, it is confirmed that the sealing part 3 is prevented from being damaged by setting a ≦ 2.5b. It can also be seen that the thinner the bulb diameter, the less the arc jumps.

In the above embodiment, the lead wire 10,
Since the bead glass 9 attached to 11 constitutes the shielding member of the present invention, no special shielding member is required, and the supporting structure of the shielding member is simplified, and the pair of lead wires 10, The interval of 11 is kept constant by this shielding member (bead glass 9).

Further, in the above embodiment, the elliptic spherical portion 5
The filament 8 is housed in the cylindrical portion 4
Since the bead glass 9 is housed in, the discharge is unlikely to cross over to the sealing portion 3 side. That is, since the cylindrical portion 4 is formed thinner than the elliptic spherical portion 5, if the bead glass 9 is housed in the cylindrical portion 4, a narrow gap is formed between the outer periphery of the bead glass 9 and the inner surface of the cylindrical portion 4. , It becomes difficult for the discharge to pass through.

Then, the infrared reflecting film 7 is formed on the surface of the bulb 2.
In the case where the above is provided, the infrared rays emitted from the filament 8 are reflected by the infrared reflecting film 7 and returned to the filament 8 and the filament 8 is heated, so that the efficiency is improved. It rises compared to the case where 7 is not provided. Such a filament 8
Is transmitted to the encapsulation part 3 as radiant heat and may cause a rise in the temperature of the encapsulation part 3 and the molybdenum foil 12 and the like may be oxidized at an early stage. It becomes difficult to reach the stopper 3, and thus the sealing portion 3
It is possible to prevent the temperature rise. In this case, an extension line L connecting the end of the filament 8 and the outer edge of the bead glass 9 passes outside the sealing portion 3,
In other words, from the end of the filament 8 to the bead glass 9
Since the sealing portion 3 is present within the expansion angle θ of the outer edge of the bead glass 9 when facing, the filament 8 and the sealing portion 3 sandwich the bead glass 9 and are shaded from each other. Therefore, the heat of the filament 8 is blocked by the bead glass 9 and thus it is difficult to reach the sealing portion 3, and the temperature rise of the sealing portion 3 can be prevented more reliably.

When the sealing portion 3 is crushed and sealed, the sealing portion 3 is heated and softened. In this case, silicon oxide SiO ₂ which is a quartz material is sublimated and tends to diffuse into the bulb 2. However, the sublimation of the silicon oxide is also blocked by the bead glass 9, and the diffusion into the bulb 2 is suppressed.

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. 6 is used. It can be implemented even in the case. That is, in FIG. 6, 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 a bead glass corresponding to a shielding member, and 9a is an anchor.
Wires, 10 and 11 are internal lead wires, 12 and 13 are molybdenum foils, 16 is an insulating base, 18 is a screw type base,
19 is a terminal. Even in the case of such a cylindrical one-side sealed halogen light bulb, if the conditions of the present invention are satisfied, the bulb can be prevented from being damaged even if discharge occurs at the end of its life. The shape of the shielding member and the bead glass is not limited to the oval shape or the rod shape, and may be a disk shape or the like.

[0047]

As described above, according to the invention of claim 1, the relation between the maximum inner diameter a of the valve and the minimum width b of the shielding member at the portion where the shielding member is provided is a ≦ 2.5b. Therefore, even if a discharge occurs due to the filament breaking at the end of the life, the discharge is prevented from extending to the sealing portion. Therefore, it is possible to prevent the occurrence of an arc spot at the connecting portion of the metal foil conductor of the sealing portion, and to prevent the sealing portion from being damaged.

According to the second aspect of the present invention, since the shielding member is made of bead glass supported by the lead wire, no special shielding member is required, and the supporting structure for the shielding member is simple. The distance between the pair of lead wires is kept constant by the shielding member.

According to the invention of claim 3, since the cylindrical portion is formed thinner than the spherical portion, when the shielding member is housed in the cylindrical portion, the space between the outer periphery of the shielding member and the inner surface of the cylindrical portion is further increased. It becomes a narrow gap, which makes it difficult for the discharge to pass through. Therefore, the discharge is prevented from extending to the sealed portion.

According to the fourth aspect of the present invention, since the infrared reflecting film which transmits visible light is provided on either the inside or outside of the bulb, the infrared rays emitted from the filament are reflected by the infrared reflecting film and the filament is reflected. The efficiency is improved because the filament is heated again. Then, the heat of the filament is blocked by the shielding member and does not easily reach the sealing portion, so that the temperature rise of the sealing portion can be prevented.

According to the invention of claim 5, since the filament and the sealing portion sandwich the shielding member and are shaded from each other, the heat of the filament is shielded by the shielding member during lighting and it is difficult to reach the sealing portion. Therefore, the temperature rise of the sealing portion can be prevented more reliably. According to the invention of claim 6, it is possible to provide a reflection type illumination device that makes the most of the advantages of the incandescent lamps of claims 1 to 5.

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

FIG. 4 is a view for explaining the action of the halogen light bulb of the same embodiment.

FIG. 5 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. 6 is a perspective 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 ... Bead glass (shielding member) 20 ... Reflector 21 ... Reflecting surface 22 ... Reflector

Claims (6)

[Claims] 1. A valve having a sealing portion formed at one end; a filament contained in the valve; a shielding member provided in the valve between the sealing portion and the filament;
An incandescent light bulb comprising: a ≦ 2.5b, where a is the maximum inner diameter of the portion of the bulb where the shielding member is located and b is the minimum width of the shielding member. 2. The incandescent lamp according to claim 1, wherein the shielding member is made of bead glass supported by a lead wire. 3. The valve has a sphere, an ellipsoidal sphere, or a spherical portion similar to these, a cylindrical portion and a sealing portion which are continuous with the spherical portion, the filament is accommodated in the spherical portion, and the cylindrical portion shields the filament. The incandescent lamp according to claim 1 or 2, wherein a member is housed. 4. The incandescent light bulb according to claim 1, wherein the bulb is provided with an infrared reflection film that transmits visible light on either the inside or the outside surface. 5. The extension line of a line connecting one end of the filament and the outer periphery of the minimum width portion of the shielding member passes through the outside of the sealing portion. Incandescent light bulb as described in. 6. A reflection type illumination device comprising: the incandescent lamp according to claim 1; and a reflector incorporating the incandescent lamp.