JP2005251448A - Low-pressure mercury vapor discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-pressure mercury vapor discharge lamp capable of suppressing temperature variation of the coldest point part, of suppressing dispersion of lamp characteristics, and of improving the lamp characteristics. <P>SOLUTION: This low-pressure mercury vapor discharge lamp comprises: a double spiral arc tube 2; a holder 3 for holding both ends of the arc tube 2; a lighting circuit 4 formed on the side opposite to the arc tube of the holder 3; a case 6 mounted to the holder 3 so as to cover the lighting circuit 4 while having a bulb base 5; and an outer tube 7 mounted by covering the arc tube 2. At a tip part 8 on the side opposite to the holder 3 of the arc tube 2, a projection part 9 is formed as a coldest point presumption part becoming the coldest point part in light emission. The projection part 9 being the coldest point presumption part of the arc tube 2 contacts the outer tube 7, and the projection part 9 thermally directly contacts the outer tube 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a low-pressure mercury vapor discharge lamp provided with a curved arc tube in an outer tube.

  As a low-pressure mercury vapor discharge lamp provided with a curved arc tube in the outer tube, for example, a light bulb-type fluorescent lamp instead of a general light bulb is known.

  As a conventional bulb-type fluorescent lamp, there is a lamp with an outer tube provided with a curved arc tube 2 in an outer tube 7 as shown in FIG. In the case with the outer tube, the arc tube 2 held by the holder 3 is covered with an outer tube 7 made of glass in the shape of a glass, and a lighting circuit 4 (not shown) is provided on the side of the holder 3 opposite to the arc tube. A case 6 provided with the same E-shaped base 5 as that of a general light bulb is mounted on the holder 3 so as to cover the lighting circuit 4.

  As the arc tube 2, a double spiral tube is used, and this double spiral tube 2 is a straight glass tube bent into a double spiral shape. A pair of tungsten coil electrodes filled with an electron emitting material are hermetically sealed at both ends of the tube, and a phosphor is applied to the inner surface of the tube. Also, mercury Hg and argon as a buffer gas are contained in the tube. Noble gas is enclosed.

  By the way, it is well known that in a bulb-type fluorescent lamp with an outer tube, mercury enclosed in the arc tube is not a simple substance but is enclosed in the form of an amalgam such as Bi-In-Hg. This is because the mercury vapor pressure in the arc tube, which has a relatively high temperature, is reduced / adjusted so that the lamp efficiency is within the optimum range with the highest efficiency, because the outer tube is provided during steady lamp operation. is there.

In addition, in order to suppress an increase in mercury vapor pressure in the type with the outer tube, the mercury in the arc tube 2 is basically sealed in the form of a single unit with the outer tube, and the coldest spot 9 of the arc tube 2 Means have been proposed in which the outer tube 7 is coupled to the outer tube 7 by a heat conductive medium 12 to thereby reduce the temperature at the coldest spot (for example, Patent Document 1 and Patent Document 2).
JP 58-177891 A JP 2003-263972 A

  In a low-pressure mercury vapor discharge lamp equipped with an arc tube made of a curved glass tube such as a double helix, mercury is enclosed in the arc tube or in a form close to a single unit, and the inside diameter of the arc tube is 5 to 9 mm. By combining the arc tube's planned coldest spot, which is the coldest spot during light emission, and the outer tube with a thermally conductive medium made of silicone resin, the luminous flux rise characteristic at the start of the lamp is equivalent to that of a general fluorescent lamp. It is possible to set the temperature at the coldest spot of the arc tube to an optimum range of 60 to 65 ° C. at which the maximum lamp efficiency can be obtained, and thus a lamp efficiency of 63 lm / W or higher is achieved. I found out that

  However, according to this configuration, it has been found that the range of variation in lamp efficiency between lamps completed in mass production is relatively large. For example, in a mass production lot of a 12W product type instead of a general light bulb 60W using a double spiral arc tube, a variation range of lamp efficiency of 58 to 68 lm / W was confirmed.

  As a result of analysis of this factor, it was found that the temperature of the coldest spot fluctuated relatively greatly among the completed lamps due to variations in the filling amount and filling shape of the silicone resin as the heat conductive medium 12. . It has also been found that if the fluctuation of the coldest spot temperature can be suppressed, the variation range of lamp efficiency can be narrowed and the average value can be increased.

  The present invention has been made to solve such problems, and suppresses temperature fluctuations at the coldest spot, does not cause variations in lamp characteristics between lamps, and improves lamp characteristics. The object is to obtain a low-pressure mercury vapor discharge lamp that can be produced.

  The low-pressure mercury vapor discharge lamp according to claim 1 is provided with an arc tube having a pair of electrodes at both ends and a curved discharge path inside the outer tube, and the arc tube is the outermost during light emission. While having the coldest spot planned location used as a cold spot location, the said coldest spot planned location has the structure which contacted the said outer tube directly.

  Invention of Claim 2 has the structure which the part of the outer pipe | tube in which the said coldest-spot scheduled location and this coldest-spot planned location directly contact | connect and have the direct contact in the structure of Claim 1. .

  Invention of Claim 3 has the structure by which the location where the said coldest-spot planned location and the said outer tube | pipe are directly contacting in the structure of Claim 1 or Claim 2 was welded.

  According to the first aspect of the present invention, unlike the conventional case, a heat conductive medium is not used, so that variation in lamp characteristics between lamps caused by the amount of the heat conductive medium and the filled shape can be suppressed. In particular, fluctuations in the coldest spot temperature of the arc tube between mass-produced lamps can be suppressed, so that the variation range of lamp efficiency can be reduced and the average value thereof can be increased, and the lamp efficiency characteristics are further improved. In addition, a stable low-pressure mercury vapor discharge lamp can be obtained.

  According to the second aspect of the present invention, heat can be more easily transferred to the outer tube as the contact area increases. In addition, it is possible to relatively easily contact and weld the coldest spot of the arc tube to the outer tube.

  According to the third aspect of the present invention, since the directly contacted portion is welded, the glass thickness is increased, the strength can be obtained, and damage due to vibration or impact during lamp transportation can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A light bulb-type fluorescent lamp 1 (hereinafter referred to as the present invention A) as a first embodiment of the present invention shown in FIG. 1, which is a substitute for a general light bulb 60W, is a double spiral arc tube 2 and the arc tube 2 And a series inverter type lighting circuit 4 (indicated by a broken line in the figure) provided on the side opposite to the luminous bulb of the holder 3 and a light bulb base 5, and a lighting circuit 4, a funnel-shaped case 6 attached to the holder 3 so as to cover 4, an arc tube 2 that covers the arc tube 2, and an opening is formed by the inner peripheral surface of the large-diameter side opening of the case 6 and the outer peripheral surface of the holder 3. And a glass outer tube 7 having a shape formed by being fixed to the gap with an adhesive.

  The arc tube 2 is a curved double spiral glass tube formed by processing straight tube glass into a so-called spiral shape, and electrodes (not shown) are sealed at both ends. A fluorescent material is applied to the inner surface of the arc tube 2, and in addition to about 5 mg of mercury, 550 Pa of argon as a buffer gas is sealed in the tube. A three-wavelength region phosphor was used as the phosphor. Further, the mercury sealed in the arc tube 2 is basically present in such a form that the mercury vapor pressure during operation of the arc tube 2 exhibits a vapor pressure value of mercury alone. Therefore, in the manufacturing process of the arc tube 2, the mercury may be single or may be sealed in the form of, for example, zinc mercury or tin mercury in which the mercury vapor pressure during the operation exhibits a value close to that of the single mercury.

  The inner diameter of the arc tube 2 is 8.2 mm, the distance between the electrodes is 400 mm, the arc tube 2 has a double spiral shape of about 4.5 turns, and mercury is enclosed in the tube in the form of single or close to the single as described above. ing. Further, a protruding portion 9 is formed as a coldest spot planned portion that becomes the coldest spot during light emission (during the travel) at the tip 8 on the side opposite to the holder 3 of the arc tube 2, and thereby, mercury The vapor pressure during operation is uniquely determined by the temperature at the coldest spot.

  The outer tube 7 has an outer diameter of 55 mm and a thickness of about 1.3 mm. The inner surface of the outer tube 7 is coated with a diffusion film (not shown) having a total diffusion transmittance of about 97% mainly composed of calcium carbonate.

  The projection 9 which is the coldest spot of the arc tube 2 has a height of 3 mm and a thickness of about 0.06 mm, and its outer surface is in contact with the outer tube 7. Direct thermal contact. The total length of the lamp was 110 mm.

  Next, the product A of the present invention was compared with a comparative product described later shown in FIG.

  In the comparative product shown in FIG. 3, a translucent silicone resin 12 as a heat conductive medium is interposed between the outer tube 7 and the protruding portion 9 which is the coldest spot of the arc tube 2 with a predetermined thickness of about 2 mm. The projection 9 of the arc tube 2 and the outer tube 7 are thermally connected by the silicone resin 12. Further, a gap of about 1.7 mm is opened between the protruding portion 9 of the arc tube 2 and the outer tube 7, and this gap is filled with a silicone resin 12. Fifty comparative products having such a configuration were produced, and their lamp characteristics were measured. As a result, the average value of the lamp efficiency was 63 lm / W, and the variation range was 58 to 68 lm / W.

  On the other hand, the variation width of the lamp efficiency in the product A of the present invention is reduced to a range of 64 to 70 lm / W, and the average value of the lamp efficiency is improved from 63 lm / W of the comparative product to 67.4 lm / W. I understood. In addition, it has been found that the rise characteristic of the lamp luminous flux is improved to a level of about 40% or more at the time of steady lighting at a room temperature of 25 ° C. after 3 seconds of starting.

  As described above, according to the first embodiment of the present invention, unlike the conventional case, a heat conductive medium is not used. Therefore, the lamp characteristics between the lamps caused by the amount of the heat conductive medium and the filled shape are reduced. Variations can be suppressed, especially the variation in the coldest spot temperature of the arc tube between mass production lamps, so that the variation range of lamp efficiency can be reduced and the average value of the lamp characteristics can be improved, In addition, a low-pressure mercury vapor discharge lamp having more excellent lamp characteristics and stable quality can be obtained.

  Next, a second embodiment of the present invention will be described with reference to the drawings.

  A bulb-type fluorescent lamp 10 (hereinafter referred to as the present product B), which is a second embodiment of the present invention shown in FIG. Among them, a recess 11 that is recessed outward by about 1.0 mm is formed at a portion where the projection 9 of the arc tube 2 contacts, and the projection 9 of the arc tube 2 is fitted into the recess 11. And the projection 9 and the outer tube 7 which are the coldest spots are in direct thermal contact with each other. The outer surface of the recess 11 of the outer tube 7 protrudes about 1 to 2 mm outward. In the product B of the present invention, it was confirmed that the variation width of the lamp efficiency was further reduced to the range of 66 to 71 lm / W, and the average value further increased to 68.3 lm / W. It was also found that the rise characteristic of the lamp luminous flux was improved to the same level as that of the product A of the present invention. Further, it is possible to relatively easily weld a protruding portion 9 of the arc tube 2 to be described later and the outer tube 7.

  In the products A and B of the present invention, the projection 9 and the outer tube 7 which are the coldest spots of the arc tube 2 are in direct contact with each other by contact, but are welded at the contact portions. The same effect can be obtained. Further, the strength is increased at the welded portion, and the strength against vibration and impact during lamp transportation can be improved.

  In the case where the protruding portion 9 of the arc tube 2 is in direct contact with and welded to the outer tube 7, conventionally, when the protruding portion 9 of the arc tube 2 and the outer tube 7 are brought into direct contact, the arc tube 2 is caused by external impact or the like. Although it was thought to be easily broken, it was found that the strength was improved contrary to expectations. This is because the protruding portion 9 of the arc tube 2 and the outer tube 7 are in direct contact with each other and are welded, so that the thickness of the glass is increased at the directly contacted portion and the strength is improved. It is believed that there is.

  The present invention can be applied not only to a double spiral arc tube but also to a bulb-type fluorescent lamp using an arc tube in which three U-tubes or four U-tubes are connected. The lamp is provided with a light emitting tube having a spot and an outer tube covering the light emitting tube, and can be effectively applied particularly to a low-pressure mercury vapor discharge lamp that requires temperature control at the coldest spot.

  The present invention can be applied not only to a double spiral arc tube but also to a bulb-type fluorescent lamp using an arc tube in which three U-tubes or four U-tubes are connected. The lamp is provided with a light emitting tube having a spot and an outer tube covering the light emitting tube, and can be effectively applied particularly to a low-pressure mercury vapor discharge lamp that requires temperature control at the coldest spot.

1 is a partially cutaway front view of a bulb-type fluorescent lamp according to a first embodiment of the present invention. Partially cutaway front view of a bulb-type fluorescent lamp according to a second embodiment of the present invention Partially cutaway front view of a conventional bulb-type fluorescent lamp

Explanation of symbols

2 arc tube 3 holder 4 lighting circuit 5 base 6 case 7 outer tube 9 protrusion 11 recess

Claims (3)

An arc tube having a pair of electrodes at both ends and having one curved discharge path inside is provided in the outer tube, and the arc tube has a coldest spot planned location that becomes the coldest spot during light emission. And the coldest spot is in direct contact with the outer tube. 2. The low-pressure mercury vapor discharge lamp according to claim 1, wherein the coldest spot expected location and the portion of the outer tube where the coldest spot expected direct contact is fitted and in direct contact. The low-pressure mercury vapor discharge lamp according to claim 1 or 2, wherein a portion where the coldest spot is directly in contact with the outer tube is welded.

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