Lamp with integrated electronic module

Abstract: A lamp includes a sealed lamp envelope (1) enclosing a filament (10), a screw shell (2) connected to the lower portion of the envelope, and electrical leads (6,8) extending from the filament into the screw shell. The screw shell has a bottom opening, in which is mounted an electronic control module (3). The electronic module is retained in the screw shell by an insulator (4a,4b). A spring (5) is compressed between the electronic module and an exhaust tube (7) on the lower portion of the envelope. One electrical lead (6) is electrically coupled from the module through the spring to the filament, allowing the module to control the filament. The insulator defines a cavity for retention of the electronic module in a fixed position.

Description: This invention relates to lamps. More particularly, this invention relates to a lamp having an electronic module mounted in the base of the lamp with which to control the filament of the lamp. A typical incandescent light bulb includes a sealed, light-transmissive lamp envelope which encloses a filament. The filament has electrical leads which extend through a lamp stem to a base portion. The base is typically an aluminum or brass shell in the form of a screw with a glass insulator and a center contact at the bottom, or the base may take the form of a bayonet fitting. An incandescent light bulb can be controlled by one of several types of electronic modules. These modules, each of which is designed for a specific purpose, have circuitry to control the light output of the lamp, causing the lamp to flash, to automatically dim over a period of time, to dim in steps, or to perform some other desired function. Suitable electronic modules are disclosed in US-A-5,126,634, and US-A-5,030,890. US-A-5,126,634 also discloses an incandescent lamp with integrated control circuitry. It is desirable to provide an incandescent lamp wherein an electronic module is mounted within the lamp base so that the lamp can be installed in a conventional lamp socket. The lamp preferably is low in cost, easy to manufacture and highly reliable. Viewed from one aspect of the present invention there is provided a lamp comprising: a lamp envelope enclosing a filament and including electrical leads extending from the filament through the lamp envelope; a lamp base attached to the lamp envelope; and an electronic module mounted in the lamp base, said module including circuitry for controlling the filament; characterised in that a conductive resilient member is compressed between an upper portion of the electronic module and a lower portion of the lamp envelope, one electrical lead being coupled to said resilient member for electrical connection to said electronic module. A resilient member compressed between the electronic module and the lamp envelope, preferably a spring, can be used to electrically couple one of the electrical leads extending from the filament to the electronic module. At the same time this spring can be used to retain the electrical lead, for example between the spring and against an exhaust tube of the lamp envelope. The lower portion of the lamp envelope preferably includes an exhaust tube which could be arranged so that it has a larger diameter than the spring. Preferably the electronic module is at least partially enclosed by an insulator to retain the electronic module in position. In a preferred form the insulator might comprise two halves. Each of the halves would preferably include some form of male-female locating connector, for example, a rib portion and a slot, in which the rib portion of one half mates with the slot of the other half. The lamp base could take the form of a shell that has an opening in which the insulator is retained. The assembly can be installed in a conventional household lamp socket by the shell taking the form of screw, bayonet or similar fitting. The insulator preferably includes a peripheral groove, and the opening in the bottom of the shell can be defined by a flange. This peripheral groove may be dimensioned to engage the flange. In this way the use of adhesive can be avoided. An insulator can define a partially enclosed cavity for retention of the electronic module and for limiting axial and lateral movement of the electronic module in the lamp. An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Fig. 1 is an exploded view of a lamp according to an embodiment of the present invention; Fig. 2 is a cross-sectional view of a portion of the lamp of Fig. 1; and Fig. 3 is an exploded top view of an electronic module and insulator used in a lamp. Figure 1 shows a lamp 50 according to a prefered embodiment of the present invention. A filament 10 is mounted within a sealed, light-transmissive lamp envelope 1. Electrical leads 6 and 8 are coupled to the filament and extend through a lamp stem (not shown). Lead 6 extends into the center portion of an aluminum screw shell 2. Lead 8 is bent around the neck portion of the lamp envelope and is connected to screw shell 2 in the completed lamp assembly. The screw shell has a side wall 15 which is threaded so that the assembly can be installed in a conventional light socket. At the lower portion of the screw shell is a generally circular opening 31 defined by a flange 30. An exhaust tube 7 extends from the lower portion of the envelope and is surrounded by the shell when the lower portion of the envelope is mounted to screw shell 2 as shown in Fig. 2. Centered below envelope 1 and screw shell 2 is a circular, generally disc-shaped electronic module 3. The electronic module 3 can be constructed as disclosed in the aforementioned US-A-5,126,634 and US-A-5,030,890. The module, which can control the light output of the lamp, is securely held on a side wall and partly on upper and lower walls by two insulator halves 4a and 4b. These insulator halves, which are preferably made from a polyetherimide such as ULTEM material produced by General Electric Co., hold the module when pressed together and prevent it from moving axially or laterally in the lamp assembly. Module 3 is aligned along axis 12 with a spring 5, the center of screw shell 2, the exhaust tube 7, and the center of envelope 1. Referring to Fig. 2, spring 5 is compressed between a conductive strap 14 of module 3 and exhaust tube 7. The spring 5 has a smaller diameter than the exhaust tube in order to prevent it from being pushed over the tube. Spring 5 is preferably fabricated of stainless steel. Wire 6 is inserted between spring 5 and exhaust tube 7 and is secured in position by spring 5, thus completing an electrical connection from filament 10 (Fig. 1) through wire 6, spring 5 and conductive strap 14 to module 3. During assembly, the lamp envelope 1 is positioned upside down. The lead 6 is placed on the exhaust tube 71 and the spring 5 positioned over the lead. The insulator and electronic module are then positioned to compress the spring and are snapped into the screw shell 2. The screw shell, the insulator halves 4a and 4b, the electronic module 3 and the spring 5 constitute a lamp base. When the lamp base is installed in a conventional household lamp socket, the line voltage is applied between shell 16 of electronic module 3 and screw shell 2. Shell 16 in the lower portion of module 3 replaces the center eyelet of a typical lamp. Referring to Fig. 3, each of the insulator halves 4a and 4b is semi-annular in shape and has a rib 18 and a pin 20 on one side, and a hole 26 and a slot (not shown) on the other side. When the two halves are coupled together around the module, pin 20 fits within hole 26, and rib 18 fits within the corresponding slot. Referring again to Fig. 2, when the insulator halves 4a and 4b are put together, there is an air gap between them. At junction 22, the ribs (Fig. 3) and pins mate with corresponding slots and holes and partially block this gap, electrically isolating electronic module 3 from screw shell 2. When the insulator halves 4a and 4b are coupled together to form an insulator, the insulator has an outside diameter in a center portion 28 which is slightly smaller than opening 31 (Fig. 1) in the lower portion of the screw shell 2. An upper portion 29 of the insulator is slightly larger in diameter than center portion 28 and forms a shoulder 32. As the coupled insulating halves and module are inserted into the opening 31 of the screw 2 shell, the upper portion 29, which is preferably tapered at about 15°, causes the opening 31 to expand. When shoulder 32 passes the flange 30, the opening contracts and the center portion of the insulator is aligned with flange 30. A bottom portion 33 of the insulator is larger in diameter than center portion 28, thus creating a lower shoulder 34 which prevents the insulator from being inserted too far into the screw shell 2 opening. Thus, bottom portion 33 prevents halves 4a and 4b from being inserted too far into the opening 31, and the upper portion 29 prevents the halves from being pushed out of the screw shell by the spring. The shoulders 32 and 34 of the insulator define a peripheral groove for receiving flange 30 of inner shell 2. The disclosed structure permits the insulator halves 4a and 4b containing electronic module 3 to be snapped into the lamp base with the flange 30 engaging the peripheral groove in the insulator. The insulator retains the electronic module 3 in a fixed position in the lamp base without requiring an adhesive. The insulator halves 4a and 4b define a partially enclosed cavity for retention of electronic module 3. The cavity is defined by an annular upper surface 50 and an annular lower surface 52 which limit axial movement of electronic module 3, and by a cylindrical outer surface 54 which limits lateral movement of electronic module 3. The spring 5 provides electrical contact between the electronic module 3 and filament 10 without solder or welding. Thus in at least preferred embodiments of the present invention there is provided a very convenient and compact arrangement; there is provided a lamp with an electronics module mounted in the base which may be mounted in a conventional lamp socket without modification of the socket; and there is provided a lamp with an electronics module which is simple in construction and easy to use.

Claims: A lamp comprising: a lamp envelope (1) enclosing a filament (10) and including electrical leads (6,8) extending from the filament through the lamp envelope; a lamp base (2) attached to the lamp envelope; and an electronic module (3) mounted in the lamp base, said module including circuitry for controlling the filament; characterised in that a conductive resilient member (5) is compressed between an upper portion of the electronic module (3) and a lower portion of the lamp envelope (1), one electrical lead (6) being coupled to said resilient member for electrical connection to said electronic module. A lamp as claimed in claim 1 characterised in that said lower portion of the lamp envelope (1) includes an exhaust tube (7) and wherein said resilient member (5) engages said exhaust tube, said one electrical lead (6) being retained between said resilient member and said exhaust tube. A lamp as claimed in claim 2, characterised in that the resilient member (5) is in the form of a spring whose diameter is less than the diameter of the exhaust tube (7). A lamp as claimed in claim 1, 2 or 3 characterised in that the electronic module (3) has a side wall and said lamp base comprises an insulator (4a,4b) for enclosing at least the side wall so that the electronic module is retained in a fixed position in said lamp by said insulator. A lamp as claimed in claim 4, characterised in that said insulator is mounted within the opening of said lamp base. A lamp as claimed in claim 4 or 5 characterised in that the insulator (4a,4b) encloses at least a portion of upper and lower walls of the module (3). A lamp as claimed in claim 4, 5 or 6 characterised in that said insulator (4a,4b) includes a peripheral groove (32,34) and the bottom opening in said lamp base defined by a flange (30), said peripheral groove being dimensioned to engage said flange. A lamp as claimed in any of claims 4 to 7 characterised in that the insulator comprises two halves (4a,4b). A lamp as claimed in claim 8 characterised in that each of said two halves (4a,4b) includes a rib portion (18) and a slot, the rib portion of one half mating with the slot in the other half. A lamp as claimed in any of claims 4 to 9 characterised in that the insulator (4a,4b) and the module (3) form an assembly which can be inserted into the opening of the lamp base and retained without an adhesive. A lamp as claimed in any of claims 4 to 10 characterised in that said insulator (4a,4b) defines a partially enclosed cavity for retention of said electronic module (3) and for limiting axial and lateral movement of said electronic module. A lamp as claimed in any preceding claim characterised in that the lamp base (2) comprises a screw shell.

Inventors: HARADEN THOMAS, HARADEN, THOMAS
Applicants: FLOWIL INT LIGHTING, FLOWIL INTERNATIONAL LIGHTING (HOLDING) B.V.
Application year: 1993
Main classification: H01K1
IPC codes: H01K1