Title:
Starter for an electric discharge lamp
United States Patent 3914646


Abstract:
The invention relates to a starter for starting a gas and/or vapour discharge lamp. According to the invention the switch element used is a transistor, the starter containing two discs made of a synthetic material which are interconnected by mechanically rigid electric conductors. Electric circuit elements form parts of the electric conductors and are included in the circuit for controlling the transistor.



Inventors:
PAUPY JEAN PIERRE
Application Number:
05/479903
Publication Date:
10/21/1975
Filing Date:
06/17/1974
Assignee:
U.S. PHILIPS CORPORATION
Primary Class:
Other Classes:
315/99, 315/100, 315/101, 315/105, 337/22
International Classes:
H05B41/04; (IPC1-7): H05B41/04; H05B41/18
Field of Search:
315/94,98,99,100,101,102,103,105,362,DIG.5 337
View Patent Images:
US Patent References:
3631317SYSTEM FOR LIGHTING A FLUORESCENT LAMP1971-12-28Miyajima
2636077Starter for fluorescent lamps1953-04-21Jacobsen



Primary Examiner:
Lawrence, James W.
Assistant Examiner:
La Roche E. R.
Attorney, Agent or Firm:
Trifari, Frank Franzblau Bernard R.
Claims:
What is claimed is

1. A starter for an electric discharge lamp comprising, a right circular cylindrical envelope, a first disc made of a synthetic material and extending in a direction at right angles to the direction of length of the envelope, a second disc which is made of a synthetic material and extends in a direction at right angles to the direction of length of the envelope, an electric circuit element of the starter forming part of a mechanically rigid electric conductor which is disposed between the two discs and extends in a direction at right angles to the discs and is secured thereto, and a semiconductor switch element which is part of the starter and is disposed between the two discs.

2. A starter as claimed in claim 1 comprising at least two electric conductors disposed between and interconnecting the two discs, one of said discs supporting an electric interconnection between said two conductors.

3. A starter as claimed in claim 1 wherein the envelope is made of a synthetic material and one of the two discs forms part of a closure member for the envelope, the closure member supporting an external electric connection for the starter.

4. A starter as claimed in claim 1, in which terminals of the semiconductor switch element are disposed in one side of this switch element, characterized in that the switch element is secured to only one of the discs made of a synthetic material.

5. A starter as claimed in claim 4 comprising at least two electric conductors interconnecting the two discs, at least one of the discs carrying an electric interconnection between said two conductors.

6. A starter as claimed in claim 5 in which the envelope is made of a synthetic material, and one of the two discs forms part of a closure member of the right circular cylindrical envelope, which member also carries the external electric connections to the starter.

7. A starter for an electric discharge lamp comprising, a container in the shape of a right circular cylinder, a first disc made of a synthetic material fixed to the container and extending at right angles to the longitudinal axis of the container, a second disc made of a synthetic material and spaced apart from the first disc and extending parallel thereto, an electric circuit element of the starter including a mechanically rigid electric conductor disposed between and secured to the two discs and extending in a direction perpendicular to said discs, and a semiconductor switching element forming a part of the starter circuit and disposed in the container between the two discs.

8. A starter as claimed in claim 7 wherein said two discs are located at opposite ends of the container so as to close the ends thereof.

9. A starter as claimed in claim 7 wherein said two discs and said electric circuit element together form an integral unit dimensioned to be insertable into the cylindrical container.

Description:
The invention relates to a starter for starting a gas and/or vapour discharge lamp, which starter has an envelope in the form of a right circular cylinder and includes a switch assembly and a first disc which is made of a synthetic material and extends at right angles to the direction of length of the envelope.

A starter of the aforementioned type is described, for example, in the book "Fluorescent Lamps" by Elenbaas, Philips Technical Library, second edition 1971, page 123. A disadvantage of the known starter is that it includes moving contact elements because it is a glow discharge starter.

It is also known to start a gas and/or vapour discharge lamp by means of a semiconductor switch element. This is described, for example, in French Pat. No. 1,582,392. However, the proposed starter has the form of a rectangular block so that it is less readily exchangeable with the aforementioned glow discharge starter.

It is an object of the invention to provide a starter for starting a gas and/or vapour discharge lamp which does not suffer from the said disadvantages. One might also say that one of the purposes is to combine the advantages of a semiconductor switch element with the exchangeability of a glow discharge starter, or to provide a semiconductor starter of a shape and size similar to of the known glow discharge starter.

A starter according to the invention for starting a gas and/or vapour discharge lamp, which starter has an envelope in the form of a right circular cylinder and includes a switch element and a first disc which is made of a synthetic material and extends at right angles to the direction of length of the envelope, is characterized in that the switch element is a semiconductor switch element and that the starter contains a second disc of a synthetic material which second disc also extends at right angles to the direction of length of the envelope. An electric circuit element of the starter forms part of a mechanically rigid electric conductor which extends in a direction at right angles to the discs of synthetic material and is secured thereto with the semiconductor switch element disposed between the two discs.

An advantage of the said starter is that the interior of the envelope comprises a very simple structure which may have a high space factor. The expression "high space factor" is to be understood to mean that a large part of the space within the starter envelope is utilized. Furthermore, the combination of the two discs of synthetic material with the circuit elements forms an integral unit which, during manufacture, may readily be inserted into the cylindrical envelope.

A further advantage of a starter according to the invention is that, for example, when it is to be used to start discharge lamps having preheatable electrodes, it is exchangeable with a glow discharge starter.

A starter according to the invention may also be used for starting a discharge lamp which does not have preheatable electrodes, for example a high-pressure sodium-vapour discharge lamp.

The semiconductor switch element of a starter according to the invention may be a non-controlled semiconductor switch element, for example a four-layer diode. Alternatively the semiconductor switch element may be a controlled element. It may for example be a thyristor or a circuit element having a bidirectional thyristor characteristic (triac). Furthermore it may be a silicon controlled switch. Also a transistor may be used as the semiconductor switch element.

The semiconductor switch element itself may be the electric circuit element which, in a starter according to the invention, forms part of a mechanically rigid electric conductor which extends in a direction at right angles to the discs of synthetic material and is secured thereto. Alternatively it may be diode, a resistor, a capacitor or another element. It may for example be a circuit element which forms part of the control circuit of the semiconductor switch element.

The terminals of the semiconductor switch element may, for example, be disposed one on either side of the element.

In a preferred embodiment of a starter according to the invention, the semiconductor switch element is a switch element having terminals which are disposed on one side of this element, the switch element being secured to only one of the discs of synthetic material.

This has the advantage of permitting a mechanically strong arrangement of the semiconductor switch element.

When the number of electric conductors which interconnect the discs of synthetic material is at least two, an interconnection for these conductors may be disposed between the two discs.

In another preferred embodiment of a starter according to the invention in which the number of electric conductors which connect the discs is at least two, at least one of the discs is provided with an interconnection for the said conductors.

An advantage of this preferred embodiment is that the interconnection may be very simple. It may for example be a small amount of solder disposed on the surface of the disc between the points at which the two conductors are secured to the disc.

The envelope of the starter may consist of a metal, for example aluminum.

In a further preferred embodiment of a starter according to the invention the envelope is made of a synthetic material, one of the two discs of synthetic material forming part of a closure member of the cylindrical envelope and being provided with external electric terminals for the starter.

An advantage of an envelope made of a synthetic material is that the assembly contained in the envelope need not be provided with further insulating materials. In addition one of the discs serves several purposes.

When the last-mentioned case interconnections are provided on the said disc, they may be disposed on the surface which faces the other disc. Also, when the interconnections are disposed on the surface facing away from the other disc, a coating of an insulating lacquer may be applied on the interconnections, or a third disc of synthetic material may be added, the interconnections being disposed between the second and third discs.

The external electric connections of the starter may take the form of terminals which fit in a starter holder which can also be used for a glow discharge starter.

The starter may have three or more connections. This may occur when it is to be used for starting a high-pressure discharge lamp, connections being made to different tappings on the choke coil.

An embodiment of a starter according to the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 shows a starter according to the invention and a known lamp circuit in which it may be used,

FIG. 2 is a perspective view of the starter of FIG. 1 with separated envelope, and

FIG. 3 shows schematically the electric connections in the starter of FIG. 2.

It should be mentioned that FIG. 2 shows part of the actual arrangement of the circuit elements of the starter, whereas FIG. 3 illustrates how the various circuit elements of the starter of FIG. 2 are electronically interconnected.

Referring now to FIG. 1, reference numerals 1 and 2 are terminals for connection to an alternatingvoltage supply of, for example, 220 V, 50 Hz. The terminal 1 is connected to a choke coil 3 which serves to stabilise the current. The other end of the coil 3 is connected to an electrode 4 of a discharge lamp 5. The electrode 4 and the other electrode 6 of the lamp 5 are of preheatable type. The lamp 5 is a low-pressure mercury-vapour discharge lamp of, for example, 40 W. The supply terminal 2 is connected to one end of electrode 6. The ends of the electrodes 4 and 6 not connected to the supply terminals 1 and 2 are connected to a starter holder having terminals 7' and 8'. A starter according to the invention is denoted by reference numeral 30. This starter has two connections 34 and 35 adapted to cooperate with the terminals 8' and 7' respectively of the electrode circuit of the lamp 5.

The starter 30 serves only to start the discharge in the lamp 5. For this purpose, during starting, a circuit element in the starter 30 is rendered conductive, permitting a current to flow from the terminal 1 through the coil 3, the electrode 4, the starter 30 and the electrode 6 to the terminal 2 and, if required, vice versa. This current provides preheating of the electrodes 4 and 6 and when the switch element is rendered non-conductive, in other words when the switch is opened, it frequently provides a voltage surge which also promotes starting of the lamp 5. As a rule, after the lamp 5 has ignited the starter 30 is automatically rendered inoperative.

FIG. 2 shows the starter 30 of FIG. 1 with a separate envelope 30a.

The diminsions of the envelope 30a, which is made of a synthetic material, are equal to those of the envelopes generally used for glow discharge starters (diameter about 2 cm and length about 3.5 cm). The starter assembly includes two discs 31 and 32 made of a synthetic material. The disc 32 is coated with a sealing material 33. Reference numerals 34 and 35 designate the terminals also shown in FIG. 1. Between the discs 31 and 32 a plurality of electrically conducting and mechanically rigid connections are disposed. Electric circuit elements form parts of these connections. For example, a connection including a resistor 19 is secured in a mechanically rigid manner at one end to the disc 31 and at the other end to the disc 32. From one side of the assembly to the other side there are shown an element 21, which represents a diar, the resistor 19, a diode 11, a capacitor 20, a semiconductor switch element 17, an auxiliary transistor 22, a diode 10 and a resistor 23. Some of the electric circuit elements of the starter are not visible in FIG. 2 because they are hidden by the circuit elements shown. However they are shown in the diagram of FIG. 3. The semiconductor switch element 17 in the starter shown is a transistor.

FIG. 3 is arranged in the following manner. The discs 32 and 31 have been pivoted through 90° to the outside 34. FIG. 3 shows conductor paths which are applied to the inner surfaces of the discs by methods generally used in printed-circuit technology and which establish the interconnections between the conductors which terminate on the discs. Alternatively these interconnections may be, for example, soldered connections. FIG. 3 further shows connections from one disc to the other. The latter connections are shown only to illustrate the electric relationship between the starter elements. The connections shown as right angled actually are straight, as is shown in FIG. 2. In FIGS. 3 and 2 like elements are designated by the same reference numerals.

In the circuit arrangement of FIG. 3 the first element connected to the terminals 34 and 35 are diodes 9, 10, 11 and 12 which together form a bridge. The element 17 is the main semiconductor switch element of the starter, whereas the transistor 22 is an auxiliary element. This auxiliary transistor switches the starter off if, within a given period of time, for example, 30 seconds, the lamp 5 of FIG. 1 has not started. This serves to avoid radio interference. The circuit element 17, 22, 10 and 11, which in FIG. 3 are shown within the circle representing the discs, actually are disposed between the two discs 31 and 32, as may partly be seen from FIG. 2. The final step in the manufacture of this starter is the insertion of the assembly shown in the lower part of FIG. 2 into the envelope 30a made of a synthetic material, the combinations of the discs 32 and 33 being secured to the lower end of the envelope 30a by a snap joint, not shown. Then the starter is placed above the holder shown in FIG. 1 and the connecting parts 34 and 35 are inserted into the corresponding openings 8' and 7' respectively. The starter then is capable of starting the lamp 5 (FIG. 1).