Electric lamp and discharge devices – Having heating means to control gas/vapor – gas or vapor... – Vapor generating
Reexamination Certificate
2000-07-12
2002-11-05
Day, Michael H. (Department: 2879)
Electric lamp and discharge devices
Having heating means to control gas/vapor, gas or vapor...
Vapor generating
C313S547000, C313S546000, C313S564000, C313S565000, C313S566000
Reexamination Certificate
active
06476553
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a fluorescent discharge tube and a bulb-shaped fluorescent lamp using the same.
BACKGROUND OF THE INVENTION
Conventionally, three types of fluorescent lamps, for example, bulb-shaped fluorescent lamps, with luminous fluxes corresponding to 40 W, 60 W, and 100 W general electric lights have been developed and commercially expanded. Among these three types, the development of the fluorescent lamps with luminous fluxes corresponding to 60 W and 100 W general electric lights, which have high sales distribution ratios, has been continued. Recently, particularly in order to replace small general electric lights, the size of lamps is reduced increasingly in lamp design. Bulb-shaped fluorescent lamps having discharge tubes with various configurations have been proposed and commercialized.
As shown in
FIGS. 11 and 12
, a discharge tube formed of three U-shaped glass tubes joined with bridge junctions has been used in conventional bulb-shaped fluorescent lamps. In such a discharge tube, high lamp efficiency is achieved by increasing the length of a discharge path, and the size reduction of the lamp as an object also is achieved (JP 1-220360 A and JP 9-147795 A). Similarly, as shown in
FIG. 13
, a discharge tube formed of four U-shaped glass tubes joined together to increase the length of a discharge path also has been known (JP 9-106782 A).
However, in a bulb-shaped fluorescent lamp using a discharge tube formed of at least three U-shaped glass tubes having a long discharge path and many bends, an inherent problem arises because the lamp requires a longer rise time with respect to luminous flux at a start of its operation than that in, for example, a conventional discharge tube formed of two U-shaped glass tubes joined together.
Therefore, in order to improve such characteristics in rise time with respect to luminous flux (hereinafter referred to as “luminous-flux rise characteristics”), a layout method in which one main amalgam
55
and four auxiliary amalgams
52
,
53
,
56
, and
57
are combined, as shown in
FIG. 11
, is disclosed. That is, one main amalgam
55
is placed inside a small tube
54
at an end of a U-shaped glass tube positioned at an end of a discharge tube
46
. On the other hand, the two auxiliary amalgams
52
and
53
are placed in locations adjacent to electrodes
50
and
51
, respectively, and the other additional auxiliary amalgams
56
and
57
are placed at both end portions of the U-shaped glass tube
48
and in a discharge path.
As shown in
FIG. 12
, in a discharge tube
58
formed of three U-shaped glass tubes
59
,
60
, and
61
, a layout method in which two main amalgams
66
and
67
and three auxiliary amalgams
68
,
69
, and
70
are combined is employed. That is, the two respective main amalgams
66
and
67
are placed inside small tubes
64
and
65
at one end of the U-shaped glass tubes
59
and
61
, respectively, positioned at the ends of the discharge tube
58
. On the other hand, the two auxiliary amalgams
68
and
69
are placed in locations adjacent to electrodes
62
and
63
, respectively, and another additional auxiliary amalgam
70
is positioned at an end portion of the U-shaped glass tube
60
and in a discharge path.
Furthermore, as shown in
FIG. 13
, in a discharge tube
75
formed of four U-shaped glass tubes
71
,
72
,
73
, and
74
, a layout method in which one main amalgam
81
and three auxiliary amalgams
78
,
80
, and
79
are combined is employed. That is, the two auxiliary amalgams
78
and
79
are provided in the vicinities of the electrodes
76
and
77
at the ends of the discharge tube
75
. The other auxiliary amalgam
80
is provided at an end portion of the U-shaped glass tube
72
so as to be positioned substantially midway in a discharge path. The main amalgam
81
is placed at a location adjacent to the auxiliary amalgam
80
at an end of the U-shaped glass tube
73
.
Such conventional techniques can achieve the size reduction in bulb-shaped fluorescent lamps using discharge tubes formed of at least three U-shaped glass tubes joined together, but still cannot obtain sufficient luminous-flux rise characteristics. In other words, while general electric lights have a luminous flux value corresponding to 100% of the luminous flux during a stable operation directly after a start of operation, the bulb-shaped fluorescent lamps according to the above-mentioned conventional techniques merely has a luminous flux value corresponding to 20% or lower of the luminous flux during a stable operation, even after three seconds from a start of operation. In this case, according to the study of the present inventors, it was found that the luminous-flux rise characteristics of the lamps depended on the non-operation time after a stop of operation, and particularly, in the case of a relatively short non-operation time of one to six hours after a stop of operation, the lamps required a longer rise time with respect to luminous flux, which was the biggest problem.
Such slow luminous-flux rise characteristics were not a big problem when the lamps were operated continuously for many hours for business use in shops, department stores, and the like in a conventional main application field. However, this problem should be solved when the lamps are to be used for residential lighting which will be turned on and off frequently. It can be said that this problem is a hindrance to the wide use of bulb-shaped fluorescent lamps as lamps for residential lighting.
SUMMARY OF THE INVENTION
The present invention is intended to obtain a small fluorescent discharge tube having further improved luminous-flux rise characteristics, even when a non-operation time after a stop of operation is relatively short, and a bulb-shaped fluorescent lamp using the same.
In order to achieve the aforementioned object, a fluorescent discharge tube of the present invention includes at least three U-shaped glass tubes joined to form one body, electrodes provided at the ends thereof, and one discharge path formed therein. In the vicinities of the electrodes, first auxiliary amalgams are provided, and main amalgams are positioned at least in two locations in the discharge path between the electrodes. At least in one location, a second auxiliary amalgam is positioned between the main amalgams.
A bulb-shaped fluorescent lamp of the present invention includes a fluorescent discharge tube and a lighting circuit. The fluorescent discharge tube includes at least three U-shaped glass tubes joined to form one body, electrodes provided at the ends thereof, and one discharge path formed therein. In the vicinities of the electrodes, first auxiliary amalgams are provided, and main amalgams are positioned at least in two locations in the discharge path between the electrodes. At least in one location, a second auxiliary amalgam is positioned between the main amalgams.
REFERENCES:
patent: 4972118 (1990-11-01), Yorifuji et al.
patent: 5204584 (1993-04-01), Ikeda et al.
patent: 5719465 (1998-02-01), Den Breeijen et al.
patent: 5739633 (1998-04-01), Biro et al.
patent: 5814936 (1998-09-01), Martinet
patent: 6225742 (2001-05-01), Iida et al.
patent: 0 758 795 (1997-02-01), None
patent: 61-277147 (1986-12-01), None
patent: 61-277148 (1986-12-01), None
patent: 62-211850 (1987-09-01), None
patent: 1-220360 (1989-09-01), None
patent: 9-106782 (1997-04-01), None
patent: 9-147795 (1997-06-01), None
patent: 02001068060 (2001-03-01), None
patent: 02001297731 (2001-10-01), None
patent: WO 96/19823 (1996-06-01), None
Patent Abstracts of Japan, English translation of abstract, entitled “Low Pressure Mercury Vapor Discharge Lamp”, Publication No. 61277147, Date of Publication Dec. 8, 1986, one page.
Patent Abstract of Japan, English translation of abstract, entitled “Bulb Type Fluorescent Lamp”, Publication No. 62211850, Date of Publication Sep. 17, 1987, one page.
Patent Abstracts of Japan, English translation of abstract, entitled “Low Pressure Mercury Vapor Discharge Lamp”, Publication No. 61277148, Date of Publication Dec. 8, 1986
Iida Shiro
Matsumura Takeshi
Day Michael H.
Rosenthal & Osha L.L.P.
Zimmerman Glenn
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