Illumination – Light source and modifier – Fluorescent type
Reexamination Certificate
2002-03-19
2004-05-18
Ward, John Anthony (Department: 2875)
Illumination
Light source and modifier
Fluorescent type
C362S373000, C362S294000, C313S318020, C313S634000, C315S056000
Reexamination Certificate
active
06736526
ABSTRACT:
This application is based on an application Ser. No. 2001-089489 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 bulb-type lamp having a globe, such as a bulb-type fluorescent lamp and an electrodeless discharge lamp, and a manufacturing method for the bulb-type lamp.
2. Related Art
A bulb-type lamp is a kind of lamp in which a spherical globe, like the one used in an incandescent lamp, is fixed to a case. Examples of such a bulb-type lamp include bulb-type fluorescent lamps and electrodeless discharge lamps. The globe is usually made of glass in consideration of the heat generated in the lamp. Also, the globe is fixed to the case using an adhesive made of a thermosetting resin, such as a silicon resin, which has excellent heat resistance and sealing ability.
The following explains a construction of a bulb-type lamp and a method of fixing a globe to a case, taking a bulb-type fluorescent lamp as an example.
FIG. 10
is a partial broken front view of a conventional bulb-type fluorescent lamp.
This bulb-type fluorescent lamp has a globe
900
, a case
910
, an arc tube
920
, and a holder
930
. The globe
900
is made of glass and has one end opened. The case
910
is made of a resin and is engaged with the open end of the globe
900
. The arc tube
920
is made up of three U-shaped fluorescent tubes which are bridge-connected. The holder
930
is made of a resin, and is housed in an envelope formed by the globe
900
and case
910
. The holder
930
holds the arc tube
920
on one surface and an electric ballast
931
for illuminating the arc tube
920
on the other surface, and is fixed into an opening of the case
910
.
Here, a groove
940
is formed between the case
910
and the holder
930
, along the periphery of the case
910
. An edge part
900
a
of the globe
900
is inserted in this groove
940
and bonded to the case
910
through a thermosetting adhesive
941
.
Such a bulb-type fluorescent lamp can be manufactured as follows. First, the arc tube
920
and the electric ballast
931
are attached to the holder
930
. The holder
930
is then inserted into the case
910
with the electric ballast
931
being inserted first. Hence the electric ballast
931
is housed in the case
910
. Following this, the thermosetting adhesive
941
is injected into the groove
940
formed between the case
910
and the holder
930
, and the edge part
900
a
of the globe
900
is inserted into the groove
940
. The construction is then placed in a heating furnace and heated therein, to cure the thermosetting adhesive
941
. As a result, the globe
900
is fixed to the case
910
through the adhesive
941
.
With this manufacturing method, however, the globe
900
may be fixed to the case
910
in a tilted position. This causes a failure of holding the globe
900
in a correct position.
Prior to the heating process in the heating furnace, the globe
900
and the case
910
are substantially in tight contact with each other through the adhesive
941
and so the envelope formed by the globe
900
and case
910
is hermetically sealed. When the bulb-type fluorescent lamp in this state is heated in the heating furnace, the air in the envelope expands and the internal pressure increases. This being so, if the adhesive
941
is not hardened yet but is still soft, the internal pressure of the envelope may cause the globe
900
to be pushed up or tilted. If the adhesive
941
hardens in such a state, the globe
900
will end up being fixed to the case
910
in a tilted position (in more detail, the edge part
900
a
of the globe
900
is tilted upward on one side by about 4 mm). As a result, the globe
900
cannot be held in a correct position.
Bulb-type fluorescent lamps with tilted globes are all abandoned without being reused, because of their defective external appearances. Since these products are almost in finished form, they are costly and so abandoning them inevitably increases manufacturing costs.
To avoid the tilting of the globe, the following method may be employed instead of using a thermosetting resin as above. Which is to say, a stopper is provided to the edge part of the globe, whereas a stopper holding part is provided to the case. By engaging the stopper with the stopper holding part, the globe can be secured to the case. However, because the globe is made of glass, the stopper of the globe is not only difficult to form but also likely to break when engaged with the stopper holding part. For this reason, this type of bulb-type fluorescent lamp is not very practical.
The same problem can be found in electrodeless discharge lamps that have a construction similar to bulb-type fluorescent lamps, namely, a construction in which a globe is fixed to a case.
SUMMARY OF THE INVENTION
The present invention has an object of providing a bulb-type lamp that holds a globe in a correct position and so delivers an improved external appearance, and a manufacturing method for the bulb-type lamp.
The stated object can be achieved by a bulb-type lamp including: a globe having a constricted neck part at one end; a connector having a ring-shaped groove in which the neck part of the globe can be inserted, wherein the globe is bonded to the connector in a state where the neck part is inserted in the groove; a holder having a stand that supports an electric ballast; and a case having an opening, and holding the holder in a state where the holder is inserted in the case through the opening with the electric ballast being inserted first, wherein in the opening of the case, the connector to which the globe is bonded is fixed to one of the case and the holder by a fitting construction.
With this construction, the globe is held in place just by engaging the connector, to which the globe is bonded, with the case or the holder. This eliminates the need for the heating process which is conventionally performed after the envelope is formed by the globe and case. Accordingly, the tilting of the globe caused by the expansion of air in the envelope is prevented, with it being possible to hold the globe without a tilt relative to the case. As a result, the external appearance of the bulb-type lamp improves. This reduces the number of defective products, so that increases of manufacturing costs caused by abandoning defective products can be suppressed.
Here, the globe may be bonded to the connector in a state where the neck part which is inserted in the groove is kept from contact with a bottom of the groove.
With this construction, the tilting of the globe can be prevented more efficiently.
Here, the fitting construction may include a depression and a projection that fit together, the depression and the projection each being provided at a different one out of (a) the connector and (b) one of the case and the holder.
Here, the bulb-type lamp may be a bulb-type fluorescent lamp in which a fluorescent tube is supported by the stand of the holder, wherein the globe is a hollow spherical member having an open end at which the neck part is formed, a light diffusion film is formed on an internal surface of the globe using an adhesive, and the adhesive used for forming the light diffusion film is also used for bonding the globe to the connector.
With this construction, it becomes unnecessary to prepare another adhesive to bond the globe to the connector, since a single adhesive serves to form the light diffusion film and also to bond the globe to the connector. This contributes to lower manufacturing costs.
Here, the connector may be a ring having an inner wall and an outer wall which together form a U-shaped cross section, with the ring-shaped groove being present between the inner wall and the outer wall, and the globe is bonded to the connector using part of the adhesive which is gathered in the groove.
With this construction, an excess of low-viscosity adhesive which is used to form the light diffusion film can be gathered in the groove and put to use for bonding the globe to the connector.
Here, an ar
Kakuno Yoshinori
Matsuba Tetsuo
Matsushita Electric - Industrial Co., Ltd.
Ward John Anthony
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