JPH0719583B2 - Light bulb and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a light bulb comprising a semi-transparent light bulb container having an axis and an end portion, a light source within the light bulb container, and a base having a sheath portion and a base portion. Inside the base, a bulb container and an end portion of the bulb container are fixed by a thermoplastic synthetic resin adhered to both the base, and the base is an electrical contact to which a current supply conductor for the light source is connected. The present invention relates to a light bulb.

The invention also relates to a method of manufacturing such a light bulb. Such light bulbs are described and known from GB 1,380,720.

In this known light bulb, the base is a synthetic resin, for example
In this known light bulb, a thermoplastic synthetic resin of the kind constituting the base, that is, polysulfone or polyketone, is fixed to the light bulb container. That is, a ring of this polymer is placed so as to surround the end portion of the bulb container, the ring is melted, then the base is provided, and the assembly is cooled to form a butt joint between the bulb container and the base. There is.

It was confirmed that when the above synthetic resin was used, the obtained light bulb did not satisfy the IEC standard. In particular, the adhesion of the polymer to the bulb container is too weak for the conditions imposed on the torsional strength of the connection between the bulb container and the base.

It is an object of the present invention to provide a light bulb of the type mentioned above which is easy to manufacture and which has an increased torsional resistance of the connection between the light bulb container and the base.

The present invention is a light bulb comprising a semi-transparent light bulb container having an axis and an end portion, a light source in the light bulb container, and a base having a sheath portion and a base portion, wherein the base has a light bulb container. And, the end portion of the bulb container is fixed by a thermoplastic synthetic resin adhered to both the base, the base is a bulb having an electrical contact to which a current supply conductor for the light source is connected, It is characterized in that polyetherimide is used as the thermoplastic synthetic resin.

In the light bulb according to the present invention, it is preferable to connect the end portion of the light bulb container to the base in the radial direction of the synthetic resin, that is, in the direction intersecting the axis of the light bulb container. This example is advantageous because the surfaces of the synthetic resin adhered to both the bulb container and the base are relatively large. Moreover, dimensional differences in these components can be more easily tolerated, and the base can be more easily and correctly and concentrically arranged with respect to the bulb container. Therefore, the light bulb container, the synthetic resin, and the base are arranged substantially concentrically.

By providing a protrusion at the end of the bulb container that extends in the direction intersecting the axis of the bulb container and projects into the synthetic resin, the torsional strength of the connection between the bulb container and the base is significantly increased. Become. Such protrusions neutralize the shearing force at the interface between the bulb container and the synthetic resin. The homogeneity of the force at this interface is increased by distributing several, for example two or more, such protrusions along the periphery of the end portion. Such protrusions are easily obtained during the working process of shaping the end of the light bulb container. This working process is a normal process for manufacturing a normal light bulb in which the light bulb container is fixed in the base with an adhesive.

Such an effect on torsional strength is obtained by the end portion of the bulb container not being rounded, i.e. non-circular, in a cross-section which intersects the axis of the bulb container in a manner different from that described above. The end portion may be, for example, elliptical in cross section or may have one or more indentations filled with and filled with a thermoplastic synthetic resin, for example lateral or radial grooves. You can The above-mentioned protrusion has special advantages described later.

The adhesion of the synthetic resin to the material of the base, generally a metal, for example, a copper alloy such as copper-nickel, brass or Tomback, stainless steel, aluminum, new silver or nickel-plated metal, is generally greater than the adhesion of the bulb container to glass. large. In addition, the inner surface of the die that comes into contact with the synthetic resin can be shaped so as to increase the area over which the synthetic resin is applied. For this purpose, it is preferable to use an inwardly depressed metal base. in this case,
The recess is at least tangentially surrounded by a synthetic resin.

In a special embodiment of the discharge lamp according to the invention, the current supply conductor for the light source is clamped between the synthetic resin and the sheath of the base. It was surprisingly found that a base with a metal sheath makes good electrical contact between the sheath and the current supply conductor. Actually, in the case of a socket, that is, a socket having only one contact on the base portion and one contact on the sheath, or a screw socket,
It has been determined that the contacts on the base sheath can be connected to the current supply conductor as described above without the use of soldering or welding processes. This allows the manufacturing process to be very simple and very quick, and also allows the current supply conductors protruding from the bulb beyond the edge of the base to be located at any point along the periphery of this edge. It means that you can do it. This current supply conductor is different from the current supply conductor that can be made to project from the base portion of the base in only one predetermined region. Therefore, before fixing the former current supply conductor, it is necessary to first confirm where the current supply conductor is located. Yet another important advantage is that the associated current supply conductor can be short enough that it does not protrude from the base. Protruding outside the base,
Bare wires, which can be touched by conventional light bulbs, are not present in this embodiment where the current supply conductor is in the base. According to this embodiment, in a bulb with two bases each having a sheath contact, such as in a bulb with a festoon base, welding or soldering of the contacts is completely unnecessary.

General Electric Plastics (General Electric Plastics)
Very satisfactory results are obtained by using at least almost aromatic polyetherimides, such as the polyetherimides marketed by the company s) under the trade name Ultem. SiO _2, CaCO ₃ is polyether imide, MgO, Z
Mineral powders such as nO, BaSO ₄ , Al ₂ O ₃ or fibers such as glass fibers can be included.

The light bulb according to the invention can be any of several types of light bulbs, for example an incandescent light bulb whose light source is a filament. The filament can be surrounded by an inner tube arranged in the bulb container. Alternatively, the bulb may be a discharge lamp, for example a low pressure discharge lamp such as a low pressure mercury flooded discharge lamp. In this case, the light source is a mercury-containing gas which can be ionized with the electrodes arranged in the bulb container. The fill gas can be placed in the inner tube in the bulb container as in a low pressure sodium discharge lamp. The bulb may also be a high pressure discharge lamp, such as a high pressure sodium discharge lamp that emits at least almost white light. The light source in this case is an ionizing sodium-containing gas contained in a crystalline inner tube provided with an electrode.

The light bulb according to the invention can be manufactured very easily. It has also been found that it is preferable to place a preformed polyetherimide ring around the heated end of the bulb container. This step is preferably performed while the end portion is still hot, for example having a temperature of 400-450 ° C., due to the shaping process of the end portion. In one embodiment of the method of making a light bulb, the ring is at an elevated temperature, for example 150-200 ° C. When the ring is provided at the end portion, the ring adheres to the heated surface at the end portion. In this case, if desired, the ring surrounding the end can be shaped by a jig. The jig can be at a high temperature, for example 150-200 ° C. Next, a base is provided. For this purpose
Heat at a temperature of 400-450 ° C. This temperature is not critical. At temperatures around 400 ° C, the synthetic material rapidly softens and adheres. At temperatures around 200 ° C, the ring retains its shape and does not adhere to objects in contact with it. When the ring is attached to an object at a temperature of about 400 ° C, its connecting force becomes stronger during cooling.

The current supply conductor is folded around a ring provided on the end portion to provide electrical connection with the base during the step of providing the base if the base has a metal sheath. The above-mentioned steps of connecting the bases and obtaining the electrical contact require only a few seconds, for example 3 to 4 seconds, whereas the usual adhesive only cures this adhesive.
It takes about 25 seconds. Therefore, in a conventional light bulb, the process of mounting the base is one of the slowest assembling steps, which means that the light bulb according to the present invention and its manufacture are significantly improved.

In the case of a light bulb in which the end part of the light bulb container is connected to the base with a synthetic resin in a direction intersecting the axis of this light bulb container,
The synthetic resin ring is preferably in the shape of a truncated cone having an apex angle of 2 × 5 °, for example. This shape facilitates the step of providing the ring around the end portion of the bulb container. More often, the bulb container is conical on its free end side. The reason is that the glass having a sharp shape cannot be molded.

One or more protrusions provided on the end portion of the light bulb container is a particularly preferable means for reinforcing the fixation of the synthetic resin on the light bulb container. In this case, on the inner surface of the synthetic resin ring,
There may be one or more grooves that mate with the protrusions described above. By providing one or more recesses on the large-diameter end of the ring where the ring laterally engages the protrusion, a ring with a thin wall can be formed while retaining the reinforcement of the fixation of the synthetic resin on the bulb container. Can be used. Also in the embodiment described above, by sliding the ring over the end portion,
This ring can easily be provided around the end and nevertheless requires only a small amount of synthetic resin. Also, a similar recess may be provided on the small diameter end of the ring or a groove may be provided on the outer surface of the ring to accommodate the inward recess in the die.

European Patent No. 186827A2 discloses a stamped glass light bulb in which a base is connected to a bottom portion of a light bulb container through a synthetic resin skirt (sleeve). In this case, a skirt is used in place of the metal collar and the glass body (in a standard light bulb of stamped glass, the bottom of the bulb container is connected to the base through these). The synthetic resin skirt has a wide collar part with a longitudinal groove and an internal nose-shaped protrusion, which under the elastic deformation of the collar part is located in the cavity in the bottom of the bulb container. Can be engaged. Therefore, there is a mechanical connection between the bulb container and the skirt. The outer surface of the skirt is provided with a threaded portion into which the screw-in base is screwed, and the outer surface of the skirt is provided with a recess. The screw connection between them is locked against deviation. Therefore, the skirt is mechanically secured to both the bulb container and the base. The skirt is more than a means of connecting the bulb container to the base. That is, the skirt is also an insulator between the bulb container and the base, and makes the length of the bulb considerably longer than when the base is directly connected to the bulb container. An example of a synthetic resin that can be used as the skirt is polyetherimide.

The present invention will be described with reference to the drawings.

The light bulb shown in FIG. 1 has a translucent glass light bulb container 1, the axis of which is indicated by 2. The bulb container also has an end portion 3. A filament 4 acting as a light source is arranged in the light bulb container 1. In the bulb base 5 having the sheath portion 6 and the base portion 7,
The end portion 3 of the light bulb container 1 is fixed by a thermoplastic synthetic resin 8. The reason is that the thermoplastic resin 8 adheres to the bulb container and the base. The base 5 has an electric contact on a sheath portion 6, and a first current supply conductor 11 to the light source 4 is connected to the sheath portion 6. The base contact 9 in the base part 7 is connected to a second current supply conductor 12 to the light source 4. As the thermoplastic synthetic resin, polyetherimide containing 30% by weight of glass fiber is used.

The synthetic resin 8 connects the end portion 3 of the light bulb container 1 to the light bulb container 1 in a direction orthogonal to the axis 2 of the light bulb container 1. Therefore, the synthetic resin 8 and the base 5 surround the end portion 3 and the synthetic resin 8 substantially concentrically, respectively.

This end part 3 is where the end part 3 is in contact with the synthetic resin.
Has a non-circular cross section in a direction orthogonal to the axis 2 of the light bulb container 1. In FIG. 1, this non-circularity is due to the protrusion 10 (FIG. 5) extending orthogonally to the axis 2 and protruding into the synthetic resin 8.

Although not visible in FIG. 1, the end portion 3 faces the projection 10 in the radial direction and is a second similar projection (shown as 14 in FIG. 3).
Have. Therefore, these protrusions 10 and 14 are regularly distributed along the peripheral edge.

In the current supply semiconductor 11, the conductor 11 has a synthetic resin 8 and a base 5.
Due to the fact that it is clamped between the sheath part 6 and the inside of the base 5, it is in electrical contact with this base.

FIG. 2 shows a frustoconical ring 8 made of thermoplastic synthetic resin, which has a large-diameter end portion provided with two recesses 13 which are opposed to each other in the radial direction.

FIG. 3 shows a state in which the light bulb container 1 is rotated by 180 ° with respect to FIG. 1, and the container 1 is held in place by the holder 20. End part 3 is 40 for molding and cleaning.
The bulb container 1 is sealed in a vacuum airtight state by setting the temperature to 0 to 450 ° C. and closing the exhaust pipe 15 at the end of this treatment. A thermoplastic ring 8 is placed in the holder 21 containing the heating element 22 and the ring is heated to about 150-200 ° C. The retainers 20 and 21 are moved towards each other and the ring 8 is pressed onto the end portion 3. The ring 8 is melted on its inner surface and adheres to the end portion 3. This makes the recess 13 of the ring 8
Engages the protrusions 10 and 14. Therefore, the ring 8 is shaped to cooperate with the non-circular cross section of the end portion 3. A recess similar to the recess 13 may be provided at the small diameter end of the ring 8 to co-operate with the indentation present in the base 5.

The molding machine 23 shown in FIG. 4 having a larger inner surface than the inner surface of the die 5 is moved toward the retainer 20 to shape the thermoplastic ring 8.

After bending the current supply conductor 11 in a short length and aligning the current supply conductors 12 in a substantially concentric manner, the current supply conductors 12 are heated to about 400 to 450 by flame, for example.
A cage 24 having a base 5 heated to a temperature of ℃ (Fig. 5;
The base 5 is shown diagrammatically) on the ring 8,
The ring is melted at its outer surface and fixed to the sheath portion 6 of the base 5. After removing the holder 24, the base contact 9 can be connected to the current supply conductor 12 and the bulb can be cooled by an air jet.

Alternatively, the current supply conductor 11 can be shortened before depositing the ring 8 in FIG.

Although it is a light bulb of the type shown in FIG. 1, a light bulb manufactured using a polyetherimide ring 8 having no protrusions 10 and 14 and no recess 13 is described in the above-mentioned British Patent 1, 38
Compared to a similar light bulb with a similar ring of thermoplastic polyether sulfone known from 0,720.

Many bulbs were stored at 210 ° C for 1500 hours according to IEC432 (1982). The torsional proof stress of the joint portion of the base was measured and compared with a light bulb stored at room temperature for 1 hour after manufacture. The results are shown in Table 1 below.

As is clear from this table, both synthetic resins give the same fixing strength well above the standard value. After heat treatment, the fixing strength obtained with the polyetherimides according to the invention is greater than the fixing strength of known synthetic resins. Moreover, the lowest measured values are also well above the standard values, while the lowest values for known synthetic resins are lower than the standard values.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a light bulb having a base, FIG. 2 is a diagram showing a thermoplastic synthetic resin ring, and FIG. 3 is an explanatory view showing a first step of mounting the base. FIG. 4 is an explanatory view showing the second step of the same, and FIG. 5 is an explanatory view showing the third step of the same. 1 ... Light bulb container, 2 ... Axis 3 ... End part, 4 ... Filament (light source) 5 ... Base, 6 ... Sheath part 7 ... Base part 8 ... Thermoplastic synthetic resin (ring) 9 ... … Base contact, 10, 14 …… Projection 11 …… First current supply conductor, 12 …… Second current supply body 13 …… Recess, 15 …… Exhaust pipe 20, 21, 24 …… Retainer

Claims (11)

[Claims] 1. A light bulb comprising a semi-transparent light bulb container having an axis and an end portion, a light source in the light bulb container, and a base having a sheath portion and a base portion, wherein the base has a light bulb. The end portion of the bulb container is fixed by a thermoplastic synthetic resin that adheres to both the container and the base, and the base is a light bulb having an electrical contact to which a current supply conductor for the light source is connected. A light bulb characterized by using polyetherimide as a thermoplastic synthetic resin. 2. The light bulb according to claim 1, wherein the synthetic resin connects the end portion of the light bulb container to the base in a direction intersecting the axis of the light bulb container. Light bulb. 3. The light bulb according to claim 2, wherein the end portion of the light bulb container in contact with the synthetic resin has a non-circular cross section in a direction intersecting the axis of the light bulb container. Light bulb characterized by. 4. The light bulb according to claim 3, wherein the end portion of the light bulb container has a protrusion extending in a direction intersecting the axis of the light bulb container, and the protrusion is A light bulb characterized by being projected into a synthetic resin. 5. The light bulb according to claim 4, wherein the light bulb container has a plurality of the protrusions, and the protrusions are distributed over the peripheral edge of the end portion. Light bulb characterized by. 6. A light bulb according to any one of claims 2 to 5, wherein the current supply conductor for the light source is tightened between the synthetic resin and the sheath portion of the base. Is electrically connected to the sheath portion of the bulb container. 7. A light bulb comprising a semi-transparent light bulb container having an axis and an end portion, a light source in the light bulb container, and a base having a sheath portion and a base portion, wherein the base has a light bulb container. The end portion of the light bulb container is fixed by a thermoplastic synthetic resin adhered to both the base and the base has an electric contact to which a current supply conductor for the light source is connected, and the thermoplastic synthetic resin In producing a light bulb using polyetherimide as, place a polyetherimide ring around the end portion of the light bulb container having a temperature of about 400 ~ 450 ° C., a base having a temperature of about 400 ~ 450 ° C. A method of manufacturing a light bulb, comprising arranging the above-mentioned polyether imide so as to surround it. 8. A method of manufacturing a light bulb according to claim 7, wherein the ring is applied at a temperature of about 150 to 200 ° C. 9. A method of manufacturing a light bulb according to claim 7 or 8, wherein the polyetherimide ring has a truncated cone shape. 10. The method of manufacturing a light bulb according to claim 9, wherein the light bulb container is provided with an end portion having a non-circular cross section at a portion in contact with the ring, and cooperates with the end portion. A method of manufacturing a light bulb, comprising using a ring having a shape. 11. The method of manufacturing a light bulb according to claim 10, wherein the end portion is provided with at least one protrusion extending in a direction intersecting the axis of the light bulb container. A method of manufacturing a light bulb, comprising using a ring having at least one recess for the part.