KR20120109349A - Lamp - Google Patents

Abstract

PURPOSE: A lamp is provided to control white turbidity of the exterior of an inner tube by cutting ultraviolet rays emitted from a light emitting tube. CONSTITUTION: An inner tube(4) accepts a light emitting tube. An outer tube accepts the inner tube. An ultraviolet ray cutting film cuts ultraviolet rays emitted from the light emitting tube. The ultraviolet ray cutting film contains polysiloxane as a binder. At least one of the inner tube and the outer tube is fixed to a metal fixture(6) by inorganic adhesive. The inorganic adhesive contains moisture as solvent.

Description

Lamp {LAMP}

The present invention relates to a lamp having an inner tube for hermetically receiving a light emitting tube and an outer tube accommodating the inner tube, the ultraviolet cut film which cuts ultraviolet rays emitted from the light emitting tube as a lamp attached concentrically with respect to the detention. will be.

This type of lamp is mainly used for spotlights in stores and the like. Therefore, the inner tube which surrounds a light emitting tube between a light emitting tube and an outermost exterior is provided so that even if a light emitting tube is damaged, it will not be damaged to the outermost external position. An example of this kind of lamp is described in FIG. 1 of Patent Document 1 (Japanese Patent Laid-Open No. 2010-186621). A detention unit for attaching the inner tube and the outer side to the proximal end thereof includes a detention main body having a detention terminal electrically connected to the socket, and an attachment base mounted inside the detention main body while supporting the inner tube and the outer end. In the attachment base, an insertion hole for inserting and supporting the pinch-thread portion of the inner tube is formed through the post which is inserted into the open end of the outer appearance and has a roughly outer circumferential surface for outer appearance. In the inner tube, a support made of a metal thin board, which supports the inner tube concentrically with respect to the outer portion, is attached to the distal end thereof. Also, the pinch-thread portion is inserted into the insertion hole of the attachment base. The insertion hole is filled with an inorganic adhesive from the bottom opening to the position facing the outer lead welding side end portion of the molybdenum foil, and the inner tube is fixed to the attachment base. In addition, a low temperature hardening paste-type heat resistant inorganic adhesive is applied and filled between the main body of the cap and the inner tube attached concentrically to the cap body. By heating the inorganic adhesive to the curing temperature, the inner tube and the outer tube are fixed to the detention. As a low temperature hardening type paste-type heat resistant inorganic adhesive agent, the product which can harden | cure at low temperature, for example about 100-300 degreeC, and is able to withstand high temperature of 1000-2000 degreeC after hardening is marketed.

Moreover, as a preferable form for use in a store etc., there exists the lamp which provided the ultraviolet cut film in at least one of an inner tube and an outer surface so that the ultraviolet-ray radiated | emitted from a light emitting tube may not irradiate a product. This type of lamp is, for example, to provide a film of zinc oxide fine particles on the outer surface of the protective tube (inner tube or outer tube) or on the outer surface of the light emitting tube as disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 2009-152171). The ultraviolet-ray from a light emitting tube is cut by this (refer Paragraph 0004, 0005, 0006 of patent document 2).

In the compact triple tube lamp, in order to keep the light emitting tube temperature at a high temperature, the inner tube size is as small as possible. On the other hand, in order to prevent the deformation | transformation by the heat_generation | fever from a light emitting tube, and to reduce the influence at the time of light tube rupture, it is necessary for the inner tube to be a certain distance from the outer surface of a light emitting tube, and an external surface of an external appearance. In addition, since the proposition of this lamp is a lamp which is more compact than the conventional one, the external dimension is required to be designed to be extremely small. Therefore, in the compact triple tube lamp, the dimension of the inner tube has little design freedom. Patent document 3 (Japanese Patent Laid-Open No. 2008-10395) discloses design guidelines for determining the inner tube and outer dimensions of a compact triple tube lamp. However, in order to prevent breakage of the appearance in the actual rupture test, it is necessary to further increase the thickness of the appearance or to increase the distance between the inner tube and the appearance. As a result, the distance between the light emitting tube and the inner tube inner surface is practically limited to about 1.5 to 3.0 mm.

In view of the above requirements, a compact triple tube lamp with an ultraviolet cut film of 73W to 100W class was started. As a result, a new problem is that the outer surface of the inner tube becomes cloudy during the test lighting process during lamp manufacturing. It turned out to occur. This cloudy does not disappear even after continuing lighting for a long time, and the cloudy lamp loses commodity value. Therefore, in the manufacturing process, the inspection process of carrying out all visual inspection after test lighting and removing a cloudy lamp is needed.

Japanese Patent Application Laid-Open No. 2010-186621 Japanese Laid-Open Patent Publication No. 2009-152171 Japanese Patent Laid-Open No. 2008-10395

The present invention is directed to a lamp in which an inner tube for accommodating the light emitting tube and an outer tube for accommodating the inner tube are attached concentrically with respect to the detention, and an outer surface of the inner tube is provided with an ultraviolet cut film for cutting ultraviolet rays emitted from the emitting tube. Therefore, it is a technical subject to suppress the cloudiness of the inner tube outer surface which arises in the test lighting process.

The lamp according to the present invention is a lamp in which an inner tube for hermetically receiving a light emitting tube and an outer body for accommodating the inner tube are attached concentrically with respect to the detention,

The outer surface of the inner tube is provided with an ultraviolet cut film for cutting the ultraviolet rays emitted from the light emitting tube,

At least one of the inner tube and the outer tube is fixed to the cap by an inorganic adhesive, the inorganic adhesive is an adhesive having a specification containing water as a solvent,

The said ultraviolet cut film is an ultraviolet cut film of the specification containing polysiloxane as a binder,

In the light emitting space sandwiched between two end faces extending from both ends of the light emitting tube light emitting part in the outer diameter direction,

Let the average inner tube outer diameter in the same space be od [mm],

Let the average external appearance internal diameter in the same space be ID [mm],

Let the average external appearance outer diameter in the same space be OD [mm],

When the rated lamp power is P [W] and the square root of the lamp power value is Ps,

{od (ID-od)} / {Ps (OD-ID)} ≥3.4 (Equation 1)

Also

1≤ (OD-ID) ≤2 (Equation 2)

Also

70≤P≤100 (Equation 3)

Also

It is characterized by OD≤29 (Equation 4).

According to the present invention, in the compact triple tube lamp, the ultraviolet rays emitted from the light emitting tube can be cut, and the turbidity of the inner tube outer surface in the test lighting step at the time of lamp manufacture can be suppressed.

1 is an overall view showing an example of a lamp according to the present invention.
FIG. 2 is a partially enlarged cross-sectional view at cross section A of the lamp of FIG. 1. FIG.
3 is an overall view showing another example of a lamp according to the present invention.
4 is a partially enlarged cross-sectional view at a cross section A of the lamp of FIG. 3;
5 is a chart showing the presence or absence of turbidity by the start condition.
Fig. 6 is a graph showing parameters indicating conditions under which cloudiness occurs and their limits.

The structure of the compact triple tube lamp which concerns on this invention is as follows. 1 and 2 show an example of a compact triple tube lamp of class 73W. The lamp 1 has an inner tube 4 made of glass, and a light emitting tube 3 such as a ceramic metal halide lamp is housed in the inner tube 4 made of glass, and is attached to the detention 6. The exterior 5 is fixed to the detention so as to accommodate the inner tube 4. The outer surface of the inner tube 4 is provided with the ultraviolet cut film 4f at the position shown with the dotted line in FIG. 1 for convenience, and the ultraviolet cut film 5f is similarly provided with the outer surface of the exterior 5. .

The inner tube 4 is sealed at one end, and the pinch seal portion 7 is formed at the other end. A pair of lead wires (not shown) of the light emitting tube 3 are led out of the lamp body from the pinch seal portion 7. The detention 6 consists of an attachment part 11 and a detention main body 12. When assembling the lamp, the inner tube 4 and the outer surface 5 are attached to the attachment portion 11 and adhered to each other, and then the attachment 6 is integrated by adhering the attachment portion 11 to the detention main body 12. The lead wire drawn out from the pinch-seal portion 7 of the inner tube 4 is connected to two feed terminals of the detention member 6, respectively, and has a structure in which the light emitting tube 3 lights up by feeding from the outside.

FIG. 2 is an enlarged cross-sectional view of part A of FIG. 1 as viewed from the arrow direction. In Fig. 2, the central member is the pinch-seal portion 7 of the lamp body, and the periphery thereof is the lamp insertion opening 17 provided in the attachment portion 11. A part of the lamp insertion hole 17, for example, two portions of the pinch-real surface of the inner tube pinch-seal portion 7 is filled with an inorganic adhesive 18, and the attachment portion 11 and the inner tube 4 are fixed.

On the outermost periphery, the attachment part 11 of the detention is shown overlapping with the end face of the exterior 5. The external side of the attachment part 11 is smaller than the inner diameter dimension of the external appearance 5, and the inorganic adhesive 19 is filled in the two recessed parts 16 provided in the outer peripheral part, and the attachment part 11 and the external appearance ( 5) is fixed.

3 and 4 are examples of compact triple tube lamps of 100W class. It has the same structure as a 73W class lamp, with no expansion on its exterior and larger overall dimensions. Also for the constituent members, the members with the same reference numerals perform the same function under the same names as the corresponding lamp members of the 73W class.

In addition, the manufacturing process of the compact triple tube lamp is as follows.

(1) The light emitting tube 3 is placed in the inner tube 4 together with the supporting member and the power feeding member, and is hermetically sealed by a pinch-silk method after exhausting. This process can employ | adopt the manufacturing method common to the metal halide lamp marketed by the standard "G8.5."

(2) The ultraviolet cut film 4f is coated on the outer surface of the pinch-sealed inner tube 4 by a dip method or the like, and the ultraviolet cut film 4f is fired by lighting for several tens of minutes.

(3) The spacer 9 is attached to the inner tube 4, and is temporarily inserted into the outer tube 5, and the attachment portion 11 of the cap is set in the inner tube 4. As shown in FIG. After positioning of the inner tube 4, an inorganic adhesive is filled in the gap between the lamp insertion opening 17 and the pinch-seal portion 7 of the inner tube (18 in Figs. 2 and 4) and fixed to dryness. In addition, an inorganic adhesive is filled in the gap between the exterior portion 5 and the recessed portion 16 of the attachment portion 11 (reference numeral 19 in FIGS. 2 and 4) and fixed to dryness.

(4) The lead wires drawn from the pinch-seal portion 7 of the inner tube 4 are respectively connected to two feed terminals of the detention main body 12, and the detention main body 12 and the attachment portion 11 are connected to the inorganic adhesive. Secure the adhesive. At the end of this process, the lamp is in the form of FIG. 1 except for the ultraviolet cut film 5f.

(5) The ultraviolet cut film 5f is coated on the outer surface of the lamp by a dip method or the like, and the ultraviolet cut film 5f is dried at 200 ° C.

(6) After visual inspection, test lighting is performed for several tens of minutes, and then packaged after confirming that there are no defects.

In the above process, at the stage where the inorganic adhesive heat-drying step of (5) is completed, there is no lamp in which cloudiness occurs in the inner tube and the outer appearance. However, after completion of the test lighting in (6), a lamp may be found in which the outer surface of the inner tube is cloudy.

The clouding which occurs in the test lighting process of the compact triple tube lamp of the said structure was examined in detail, and the following became clear. This turbidity is the whitening of the ultraviolet cut film provided in the outer surface of an inner tube. The polysiloxane compounded as a binder in an ultraviolet-ray cut film is whitening on the outer surface of the inner tube which became heated by the lamp test lighting process, and became high temperature. Rated power which is already commercialized and mass-produced does not become cloudy in 35W lamp and 73W lamp. In addition, even though a lamp having a rated power of 73W does not have turbidity in the test lighting process in a lamp of a commercially available type, it is mixed that a 73W lamp of a prototype is produced. 100W lamp of prototype has more than 73W lamp with white cloud. Moreover, even if it was the start lamp of the same specification as the lamp which produced the cloudiness, it turned out that the lamp which cloudiness did not generate | occur | produce in the test lighting process does not produce cloudiness even if it continues lighting for thousands of hours after that.

The inventor of the present invention analyzed these phenomena and summarized the results as follows. In other words,

(1) Lamps with a rated power of 35W without clouding have a lower surface temperature than 73W lamps.

(2) A lamp with a rated power of 73W having no turbidity is a specification that has a larger bonding area between the metal fitting portion and the exterior than a lamp having a rated power of 73W without any whitening. Therefore, the exposed area of the adhesive agent to the space between the outer tube and the inner tube is large.

(3) The lamp having a rated power of 100W started has a larger size than the 73W lamp for the appearance and the inner tube, but the area of the adhesive exposed to the space between the outer tube and the inner tube is also large.

(4) The ultraviolet cut film contains polysiloxane as a binder, and it is known that an abnormal reaction occurs and it is easy to whiten in a place where there is much moisture.

From the above facts, the inventor of the present invention derives the following hypothesis.

(1) Inorganic adhesives, which bond the attachment portions with the inner tube and the exterior, are dried in the furnace body for curing, but all of the moisture is not completely released.

(2) Although the ultraviolet cut film on the inner surface of the inner tube is polymerized by hydrolysis and dehydration condensation by heating in a test-lighting step without appearance after application, the reaction temperature and reaction time are not sufficient. I) It is considered that the polysiloxane of polymerization remains.

(3) Test of lamp In the lighting step, it is necessary to keep the light emitting tube at a high temperature to a good light emission characteristic, so that the temperature of the inner tube surrounding the light emitting tube is also high. At that time, when the outer surface temperature of the inner tube becomes higher than the ultraviolet cut film firing temperature, the polysiloxane which has not been polymerized in the ultraviolet cut film firing step is going to react again.

(4) When the moisture remaining in the inorganic adhesive evaporates there and spreads to the gap space between the inner tube and the outer tube, the polysiloxane polymerization at the inner surface of the inner tube becomes an abnormal reaction, and the ultraviolet cut film which should be transparent should be whitened. .

If this hypothesis is correct, in order to solve this situation in principle, it is not impossible to completely dry the inorganic adhesive and then send it to the next step. The cost is excessive. Regarding the firing of the ultraviolet cut film, it is not a matter to put excessive manufacturing costs in order to send to the next step after the complete firing.

If this hypothesis is correct, the reason why cloudiness does not arise even if the lamp which does not generate cloudiness in a test lighting process continues after that can be demonstrated reasonably. That is, the inorganic adhesive used for the lamp like this invention becomes a porous structure after hardening. Therefore, the evaporated water spreads from the portion exposed to the gap between the inner tube and the outer tube to the gap space between the inner tube and the outer tube, and is detained in order to connect the lead wire drawn from the pinch-thread portion of the inner tube to the feed terminal of the cap. Emitted out of the lamp from a small hole in the body. In addition, water vapor is discharged out of the lamp between the main body of the detention body and the external end face or between the main body of the detention body and the attachment base. As described above, the partial pressure of water vapor in the gap space between the inner tube and the outer tube of the lamp is the highest immediately after the lamp is turned on, and the longer the lighting time is, the lower the partial pressure is. Therefore, a compact triple tube lamp is normally discharged to the outside completely within 100 hours of lighting, and if the ultraviolet cut film is not cloudy by moisture at the start, then the ultraviolet cut film does not become cloudy after that.

The following experiment was conducted to prove this hypothesis. First, two varieties of 73W and 100W were prepared as varieties of starter lamps. The 35W lamp was excluded from the experiment because the UV cut film of the inner tube did not become cloudy in any external specification.

Regarding the 73W lamp, three types of inner diameters of 15.0 mm, 15.5 mm, and 16.5 mm were prepared, and the outer diameter was 17.0 mm to 20.0 mm, 17.2 mm to 20.0 mm, 18.0 mm to 20.0 mm, and 18.0 mm to 20.0 mm. Seven types of lamps were prepared: 18.0 mm inner diameter, 21.0 mm outer diameter, 21.0 mm inner diameter, 23.4 mm outer diameter, 2.0 mm inner diameter, 25.0 mm outer diameter, and 23.0 mm inner diameter, 26.0 mm outer diameter. It was.

As the external appearance of the 73W lamp, a shape having an expansion near the center of the external appearance is adopted as in the lamp of FIG. 1. In this case, the dimension of the outer diameter or the outer diameter is perpendicular to the axis of the light emitting tube through the position shifting from the substantially cylindrical tubular portion at both ends to the light emitting tube emitting portion at the outer diameter of the light emitting tube, that is, the position at which the outer diameter of the light emitting tube starts expanding. The surface is a cross section of the light emitting tube light emitting portion, and a space sandwiched between two cross sections is used as a light emitting space. 1 and 3, the region indicated by C is a light emitting space. And the average value of the external appearance internal diameter and external appearance external diameter which change in the light emission space is defined as "average external appearance internal diameter" and "average external appearance external diameter". "Inner diameter" of the external appearance in the preceding term is "average external diameter", and "external diameter" is "average external diameter".

As for the 100 W lamp, the inner tube is prepared with four types of outer diameters of 17.5 mm, 18.0 mm, 17.7 mm, and 18.2 mm, and the outer diameter is from 20.0 mm to 22.6 mm, 22.0 mm to 25.0 mm, and 23.0 mm to 22.5 mm. Five types of 26.0 mm, inner diameter 23.2 mm, outer diameter 26.0 mm, and inner diameter 23.4 mm to outer diameter 26.0 mm were prepared, and these were combined to start each of six lamps.

All of these start lamps were manufactured by the conventional manufacturing method until the state just before a test lighting process. From these lamps, each of five specifications was first lighted for 100 hours at each rated lamp power, and the presence of cloudiness was observed. Then, the lamps of each of the remaining five specifications were turned on by connecting a ballast of a rated 90W specification to a 73W lamp, and a lamp of a 100W lamp was connected to a ballast of a rated 73W specification and turned on, and the presence of haze after 100 hours was observed.

The table which put together the specification and the result of the said experiment is shown in FIG. In the range of the lamp specification tested, it can be seen that it is possible to determine whether or not it is cloudy with the parameter shown in Expression (1). In deriving Equation 1, the inventors of the present invention found the following four points as factors influencing the difficulty of clouding.

1) The inner tube outer diameter is large.

2) The gap between inner tube and outer tube is big. In the specification with expansion near the center of the exterior, the average value in the same space is adopted as the calculated value in the light emitting space sandwiched between two end surfaces of the light emitting tube emitting portion extending in the outer diameter direction.

3) Low lamp power (affects square root of the surface of the lamp's inner tube).

4) The appearance thickness is thin.

Among the above-mentioned elements, the higher the value becomes, the more difficult the clouding is in the molecule, and the smaller the value, or the thinner, the harder the clouding is placed in the denominator.

All four factors affect the outer surface temperature of the inner tube. If the inner tube outer diameter is large, the distance from the outer surface of the light emitting tube is increased, and therefore, the inner tube temperature is relatively low. If the distance between the inner tube and the outer tube is large, it is easy to cool because a large amount of air exists outside the inner tube. If the lamp power is small, the amount of heat generated from the lamp is small, so that the inner tube temperature is relatively low. If the external thickness is thin, the difference between the external surface temperature and the external surface temperature is small. The outer periphery of the outer surface is room temperature and does not change depending on the lamp specifications. Therefore, when the external appearance thickness is thin, the temperature of the external surface of the external tube is relatively low, and since the temperature of the gap space between the internal tube and the external body decreases as a whole, the temperature of the internal tube external surface is also relatively low. In the case where the distance between the inner tube and the outer tube is large, the volume of the gap space between the inner tube and the outer tube is large, so that the water vapor pressure in the gap space is relatively low for the same amount of evaporation when water evaporates. Accordingly, the number of water vapor molecules in contact with the ultraviolet cut film provided on the inner surface of the inner tube is suppressed. For this reason, the possibility that the ultraviolet-ray cut film on an inner tube outer surface becomes cloudy is low.

The result shown in FIG. 5 is a graph of FIG. 6 by arranging the lamp power at the time of lighting on the horizontal axis and the value of Equation 1 on the vertical axis. Lamps with a cloudy inner tube are indicated by black triangles, and lamps with a non-cloudy specification are indicated by black circles. As a result, it turned out that the lamp of the specification which the value of Formula 1 becomes 3.4 or more is not turbid, but the inner tube is turbid in the lamp of the specification which the value of Formula 1 is 3.3 or less, even if it turns on and changes lamp electric power. In the lamp concerning this invention, the outer diameter of an external appearance is 29 mm or less. Since a conventional ceramic metal halide lamp has a commercially available lamp having an exterior outer diameter of 30 mm or more, it cannot be said to be a "compact" lamp unless the exterior outer diameter is 29 mm or less. In addition, the thickness of an external appearance is made into the range of 1 mm-2 mm. If it is less than 1 mm, it is not possible to sufficiently prevent external appearance damage when the light emitting tube is ruptured as a compact triple tube lamp. On the other hand, when the external thickness becomes larger, the value of Equation 1 becomes smaller, so it becomes easier to become cloudy. Lamps of practical dimensions cannot be obtained in a range satisfying the conditions of Expressions 3 and 4. Based on this experimental result, the confirmation experiment which combined the start of mass production was performed. Their specifications will be described in the following examples.

[Example 1]

An example of a 73W class lamp is shown below. The structure is the same as described with reference to FIGS. 1 and 2 above. In this example, the rated lamp power is 73 W, the inner tube outer diameter is 14.9 mm, the outer diameter in the light emitting space is 21.9 mm, and the outer diameter is 24.9 mm. Therefore, the exterior thickness is 1.5 mm and the value of (Expression 1) is 4.07. The exposed area of the inorganic adhesive is 24 mm 2 on the inner tube side and 22 mm 2 on the outer side.

When 20 lamps were started, the first test lighting was performed for 30 minutes, and the appearance and appearance of the inner tube were visually observed. As a result, no whitening of the ultraviolet cut film was observed. Even when observed after being turned on again for 100 hours, there was not one cloudy lamp. Moreover, life test was performed and the lighting was continued, and even after 5000 hours, no one was cloudy.

[Example 2]

An example of a 100W class lamp is shown below. The structure is the same as described with reference to FIGS. 3 and 4 above. In this example, the rated lamp power is 100 W, the inner tube outer diameter is 14.9 mm, the outer inner diameter is 19 mm, and the outer outer diameter is 22 mm. Therefore, the exterior thickness is 1.5 mm and the value of (Expression 1) is 4.43. The exposed area of the inorganic adhesive is 27 mm 2 in the inner tube side and 35 mm 2 in the outer side.

When 20 lamps were started, the first test lighting was performed for 30 minutes, and the appearance and appearance of the inner tube were visually observed. As a result, no whitening of the ultraviolet cut film was observed. Even when observed after being turned on again for 100 hours, there was not one cloudy lamp. Moreover, life test was performed and the lighting was continued, and even after 5000 hours, no one was cloudy.

In addition, in the 73W lamp of the conventional specification which did not produce the cloudiness, even if the numerical value of Formula 1 is about 2.6-3.0, the cloudiness of an ultraviolet cut film does not arise. This is considered to be because in the conventional 73W lamp, the exposed area of the inorganic adhesive is 24 mm 2 in the inner tube side and 17 mm 2 in the outer side, and the exposed area of the inorganic adhesive is small. In particular, the adhesive on the exterior side may have an external appearance already adhered to the inner tube around the initial drying step, and the initial moisture may be attached to the attachment portion of the cap or the external surface of the external appearance. For this reason, when the inorganic adhesive exposure area of an external side is large enough to exceed 20 mm <2>, it is thought that the ultraviolet-ray cut film of a 73W lamp may become cloudy even when manufactured by the conventional manufacturing process.

As described above, the compact triple tube provided with the ultraviolet cut film on the inner tube outer surface may cause the ultraviolet cut film to become cloudy during the test lighting step during the manufacturing process. Even in the lamp provided in the above, the ultraviolet cut film does not become cloudy at the time of manufacture, and of course, the lamp which does not become cloudy even after shipment can be realized.

The present invention contributes to the improvement of the quality and reliability of a compact triple tube type metal halide lamp comprising a light emitting tube, an inner tube accommodating the light tube, and an outer tube accommodating the inner tube.

Claims (1)

An inner tube for hermetically receiving a light emitting tube and an outer tube for accommodating the inner tube are concentrically attached to the detention apparatus.
The outer surface of the inner tube is provided with an ultraviolet cut film for cutting the ultraviolet rays emitted from the light emitting tube,
At least one of the inner tube and the outer surface is fixed to the mold by an inorganic adhesive, the inorganic adhesive is an adhesive having a specification containing water as a solvent, and the ultraviolet cut film is an ultraviolet cut film having a specification containing polysiloxane as a binder. ,
In a light emitting space sandwiched between two end surfaces of the light emitting tube emitting portion extending in the outer diameter direction, the average inner tube outer diameter in the same space is od [mm], and the average outer diameter in the same space is ID [mm]. When the average outer diameter in the same space is OD [mm], the rated lamp power is P [W], and the square root of the lamp power value is Ps,
{od (ID-od)} / {Ps (OD-ID)} ≥3.4
Also
1≤ (OD-ID) ≤2
Also
73≤P≤100
Also
A lamp, characterized in that OD≤29.

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