Electric lamp and discharge devices – With envelope – Having base and connector
Reexamination Certificate
2001-03-09
2003-06-24
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With envelope
Having base and connector
C313S113000, C362S296040, C362S216000
Reexamination Certificate
active
06583543
ABSTRACT:
This application is based on an application No. 2000-84337 filed in Japan, the content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluorescent lamp and a manufacturing method for the same. More particularly, the invention relates to improvements for enhancing the productivity of a fluorescent lamp which is equipped with a reflector to uniformize light distribution, and techniques for maintaining uniform light distribution of such a fluorescent lamp for a long time.
2. Background Art
In general, when a discharge path of a fluorescent lamp is made serpentine, a long discharge path can be formed in a small space, which enables the fluorescent lamp to be miniaturized and to be made as compact as possible.
As one example of such a fluorescent lamp, a bulb-type fluorescent lamp is well known. This fluorescent lamp has multiples of U-shaped bulbs or straight bulbs that are set annularly on a holder. The neighboring bulbs are connected by bridge connection to form such an arc tube that provides a single serpentine discharge path inside the bulbs. The fluorescent lamp is so provided with the arc tube having the serpentine discharge path, the holder for holding the arc tube, and a base provided at the end of the holder.
Such a fluorescent lamp with a serpentine discharge path has a disadvantage that the horizontal light distribution of the lamp is likely to be nonuniform. As an example of technique for improving the horizontal light distribution, a bulb-type fluorescent lamp in which a rodlike reflector is provided in a space enclosed by multiples of U-shaped bulbs is proposed (such a bulb-type fluorescent lamp is hereinafter simply called “fluorescent lamp”).
This conventional fluorescent lamp is explained below, with reference to
FIGS. 1 and 2
.
FIG. 1
illustrates a construction and manufacturing method of the fluorescent lamp. This fluorescent lamp has an arc tube
901
and a holder
902
. A rodlike reflector
905
shown in
FIG. 2
is placed on the holder
902
, to improve the light distribution of the lamp.
The arc tube
901
is composed of three U-shaped bulbs
901
a
and a bridge connector
901
b
which connects neighboring U-shaped bulbs
901
a.
The arc tube
901
is fixed to the holder
902
so as to form a discharge path annularly.
To fix the reflector
905
to the holder
902
, a stopper
905
a
is provided to the end of the reflector
905
, and a stopper holding part
902
a
is provided to the holder
902
. The stopper
905
a
has a notch with two legs.
A slit
905
b
formed between the two legs of the stopper
905
a
provides elasticity. This elasticity is exploited to insert the reflector
905
into the stopper holding part
902
a
from the side of the arc tube
901
(hereafter “arc tube side”), and engage the stopper
905
a
with the stopper holding part
902
a.
Hence the reflector
905
is fixed to the holder
902
.
However, this type of fluorescent lamp has the following problems. First, some products still suffer from gradual deterioration of light distribution. Second, the productivity of this type of fluorescent lamp is not particularly good. More specifically, when setting the holder
902
to the arc tube
901
, usually a silicon adhesive or the like is used to fix them together. Here, to keep the appearance of the lamp from being ruined by the excess adhesive which squeezes out of the contact area between the holder
902
and the arc tube
901
, it is preferable to point upward the end of the arc tube
901
with electrode lead wires, and place the holder
902
onto the arc tube
901
from above. Meanwhile, when setting the reflector
905
to the holder
902
, it is preferable to insert the reflector
905
in the direction designated by the arrow shown in
FIG. 1
, with the arc tube
901
and the holder
902
turned upside down. Thus, the arc tube
901
and the holder
902
have to be turned upside down during the manufacturing operation. This decreases the productivity of the fluorescent lamp.
SUMMARY OF THE INVENTION
In view of the above problems, the first object of the invention is to provide a fluorescent lamp with improved productivity and a manufacturing method for such a fluorescent lamp. The second object of the invention is to provide a fluorescent lamp which can maintain uniform light distribution for a long time.
The first object can be fulfilled by a fluorescent lamp including: an arc tube in which a serpentine discharge path is formed; a holder to which the arc tube is fixed at a predetermined position; and a light reflecting member which is fixed to the holder so as to have a predetermined positional relation with the arc tube, and reflects light emitted from the arc tube, wherein the light reflecting member has a reflecting part which reflects the light from the arc tube, and a fixing part which is fixed to the holder, the holder has a mounting part which includes an area that allows the reflecting part to pass through but does not allow the fixing part to pass through, and the light reflecting member is fixed to the holder by fixing the fixing part to the mounting part in a state where the reflecting part has been passed through the area.
This fluorescent lamp can be manufactured by a manufacturing method including: a holder fixing step for fixing a holder to an arc tube in which a serpentine discharge path is formed, the holder having an area that allows a reflecting part of a light reflecting member to pass through; and a light reflecting member setting step for setting the light reflecting member to the holder, by passing the reflecting part through the area from a side of the holder which is opposite to the arc tube, wherein the light reflecting member has a fixing part which cannot pass through the area, in addition to the reflecting part which can pass through the area, and the fixing part is fixed to the holder in a state where the reflecting part has been passed through the area.
With the above fluorescent lamp and manufacturing method, the process of turning the arc tube upside down becomes unnecessary, and the productivity is improved.
Also, the second object can be fulfilled by the fluorescent lamp of the above construction. The reason for this is given below.
After thorough study of the cause of degradation in light distribution of the conventional fluorescent lamp described above, the inventors of the present application found that part of the stopper
905
a
where the notch with two legs is present tends to become gradually deformed by heat generated during the illumination of the lamp. This deformation occurs in such a direction that makes the width of the slit
905
b
between the two legs smaller, and therefore brings about change in the engagement of the stopper
905
a
with the stopper holding part
902
a.
As a result, the position of the reflector
905
becomes unstable, which cause degradation in light distribution. According to the present invention, on the other hand, the diameter of the fixing part is likely to be larger than the diameter of the reflecting part. Accordingly, it is easy to prevent the occurrence of heat deformation between the reflector and the holder by taking measures such as the increase of the heat capacity of the fixing part, the divergence of heat generated during the illumination of the lamp, and the provision of a slit with one end closed, depending on the factors such as the shape of the fixing part. Hence the second object can be fulfilled.
REFERENCES:
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patent: 2000251837 (2000-09-01), None
Itaya Kenji
Matsumura Takeshi
Colón German
Matsushita Electric Industrial Co. LTD
Patel Nimeshkumar D.
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