EP0639874A2

EP0639874A2 - Multi-array twin tube lamps

Info

Publication number: EP0639874A2
Application number: EP94305609A
Authority: EP
Inventors: Edward Eugene Hammer; Edward Martin Yandek
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1993-08-10
Filing date: 1994-07-28
Publication date: 1995-02-22
Also published as: EP0639874A3; JPH08129989A; CA2129500A1

Abstract

A multi-array twin tube lamp assembly allows for increased luminous output in a compact volume. The lamp assembly comprises multiple twin tube lamps, each lamp having an electrode structure and independent discharge path. In one embodiment, the base may be modified to allow the multiple twin tube lamps to be assembled in closed proximity. Alternatively, the lampholders may be modified to allow the multiple twin tube lamps to be assembled in close proximity. The multi-array lamp arrangement may be operated at more than one discrete light level, with each lamp having its own separate voltage. Twin tube lamps may be connected electrically in parallel to essentially achieve extended lamp life.

Description

Technical Field

The present invention relates to a folded discharge low pressure lamp such as a fluorescent lamp and, more particularly, to a compacted and segmented array of lamps for increasing the lumen output characteristics in a compacted volume.

Background Art

Lamps that use mercury along with an inert gas, such as Argon, as a means of converting ultra-violet energy into visible light are classified as low pressure fluorescent discharge lamps. One such family of lamps that are commercially available are called twin tube lamps and typically range in wattage from 5W to 50W. Double twin tube lamp types, generically called quads, are also commercially available and operate within the same range of wattage. However, since quad lamps are inherently higher voltage devices than linear or twin tube lamps of equivalent length, it may be difficult to start the device due to the length of the discharge path and the bends associated with the quad lamp. This longer discharge path imposes more difficult limitations on the ballasting because of the inherently higher ballast voltages needed. Additionally, existing quad lamps are difficult and more expensive to manufacture, particularly due to the additional need to join the glass lamp tubes.
U.S. Patent 4,937,487 of Blaisdell et al discloses single bent lamp tubes used for an information display system for use as a picture element. The Blaisdell et al patent requires lamps of different colors and air flow openings in its assembly. While the lamp assembly of this patent serves well its desired needs, i.e., to change color, it has definite limitations with regard to increasing total lumen output and in fact does not even address the issue of increasing lumen output.
It is therefore highly desirable and an object of the present invention to provide an alternative approach to the present quad concept which can offer the equivalent high lumen output with the compactness feature of the quad design and do so with the lower lamp operating voltages of twin tube lamps.

Summary of the Invention

The present invention has been developed to provide such a twin tube lamp arrangement, wherein the quad concept of higher light output values in a compact volume can be accomplished by assembling existing twin tube lamps in close proximity with each other. The present invention provides a low cost option to the quad design by mechanically and electrically connecting existing twin tube lamps, without the need to join glass, as the quad lamp design requires. Total lumen output can be increased by using a multi-array of single bent tubes which are simpler and less expensive to manufacture than existing quad type lamps. Such a multi array lamp also makes it possible to design new ballasts, particularly of the electronic high frequency type, because substantially higher ballast voltages are not needed.
In accordance with one embodiment of the present invention, existing twin tube lamps can be assembled in close proximity to each other with surprisingly small decreases in efficacy due to reflectance and/or absorption losses. The multi-array lamp assembly comprises multiple twin tube lamps, each lamp having a base and being attachable to a lampholder. In one embodiment, the base may be modified to allow the multiple twin tube lamps to be assembled in closed proximity. Alternatively, the lampholders may be modified to allow the multiple twin tube lamps to be assembled in close proximity.
Accordingly, it is an object of the present invention to increase the system lumen output characteristics of the twin tube type lamps while still keeping the compactness feature of the lamp. It is also an inherent advantage of the present invention that such multi-array lamps may be operated at more than one discrete light level. It is a further advantage that the present invention provides for a family of multi-array twin tube lamps that can be made using existing twin-tube lamp equipment, at higher processing speeds with reduced cost.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

Brief Description of the Drawings

Fig. 1 is a view of a prior art twin tube lamp, for which the invention provides a means of assembling multiple of these lamps in close proximity;
Figs. 2A and 2B illustrate embodiments of multi-array lamp holders in extremely close proximity, arranged in accordance with the present invention, for holding multiples of the twin tube lamp of Fig. 1;
Fig. 3A illustrates a multi-array twin tube lamp in accordance with the present invention; and
Fig. 3B illustrates a view taken along line B-B of the multi-array twin tube lamp of Fig. 3A.

Detailed Description of the Preferred Embodiments

Existing twin tube lamp designs can be assembled in close proximity to each other with surprisingly small decreases in efficacy due to reflectance and/or absorption losses. The 'quad' concept of higher light output values in a compact volume can be accomplished in an easier and less expensive manner by assembling existing twin tube lamps, in accordance with the present invention.
Referring now to the drawings, in Fig. 1 there is illustrated an existing single bent twin tube lamp 10. The present invention provides a means of assembling multiple of such lamps 10 in close proximity, providing increased total lumen output. The twin tube lamp 10 includes an illuminating tube 12 having a first end 14 and a second end 16, with a bend area 18 which can be used for controlling the mercury vapor pressure in the lamp. The ends 14 and 16 are encased in a lamp shell base 20, having a plurality of lamp pins 22 for providing the proper electrical connection.
The present invention provides the possibility for multi-array twin tube lamps, comprised of multiple twin tube lamps 10, for increasing the total system lumen output characteristics of the twin tube type lamps 10, which otherwise would not be possible in certain cases with existing ballast technology. For example, the highest wattage quad lamp available is approximately 25 watts. With the multi-array concept, this limit can be extended to 100 watts. Such multi-array lamps may also be more easily operated at more than one discrete light level, because the lamps can be independently switched on and off. The quad concept of higher light output values in a compact volume is accomplished by assembling existing twin tube lamps 10 in close proximity with each other. This provides a low cost option to the quad design by mechanically and electrically connecting multiple existing twin tube lamps 10. Total lumen output is increased by using a multi-array of the single bent tubes 12 which are simpler to manufacture than existing quad type lamps. The multi-array twin tube lamps of the present invention can be made using existing twin tube lamps 10 which are processed at higher speeds, with the resultant lower cost relative to quad lamps.
The concept of the present invention, achieving higher light output values in a compact volume, can be accomplished in a variety of ways, without departing from the scope of the invention. For example, as illustrated in Figs. 2A and 2B, lamp holders 24 may be modified to allow existing twin tube lamps 10 to be used to increase the system lumen output characteristics of such lamp types, while still keeping the compactness feature of the lamps. Alternatively, as illustrated in Fig. 3, lamp base 26 may be modified to accomplish the desired lamp assembly. Obviously, modification of the base 26 may require related modification to the holder for accepting the lamp.
Referring to Figs. 2A and 2B, there are illustrated only two of many possible configurations for achieving the extremely close positioning of the multi-array lamp holders 24. Previously, close proximity of multiple twin tube lamps, in accordance with the present invention, was not pursued because of a slight reduction in lamp efficacy due to the inherent shorter arc discharge distances between the electrode structures of twin tube lamps as compared to quad lamps. However, the multi-array approach offers many additional advantages, including low cost, increased flexibility in the connection between the ballast and the lamp, which overcome the slight reduction in lamp efficacy that can occur.
In Figs. 2A and 2B, the lamp holders 24 comprise base pins 28 for receiving the lamp pins 22 to energize the lamps 10. The lamp holders 24 further may include mechanical alignment tabs 30 and alignment tab 32 for precise positioning of the lamp. Each lamp holder 24a, 24b, 24c, 24d, and 24e comprises a lamp holder shell 34. Finally, the lampholders may be connected by any suitable means, including mechanical connections or adhesives.
Figs. 2A and 2B illustrate three attached lamp holders and two attached lamp holders, respectively, for purposes of illustration only. It will be- obvious to those skilled in the art that additional lamp holders may be aligned or attached, to accommodate the desired number and design of multi-array twin tubes, such as is shown in Fig. 3A. Also, the lampholders may be attached in various configurations, as necessary. For example, the lampholders 24 could be designed to hold all lamps as one internal unit. Alternatively, the lampholders could be designed to permit one or more of the lamps to be selectively replaced at end of life, thereby offering the possibility of a less expensive lamp replacement at end of life.
Referring now to Fig. 3A, there is illustrated a multi-array twin tube lamp 36, having a modified lamp base 26, in accordance with the present invention. Optional connection means 38, which may be any suitable connection means including a mechanical tie and/or an adhesive, are capable of bonding a plurality of twin tube lamps and/or lampholders to provide the multi-array twin tube lamp 36. Although Figs. 3A and 3B show a pair of twin tube lamps 40 and 42, it will be obvious to those skilled in the art that the number of twin tube lamps which are connected in close proximity may vary in accordance with design requirements.
Continuing with Figs. 3A and 3B, for low ambient temperature applications, an external starting aid 44 may be incorporated into the lamp assembly 36 to facilitate starting at low temperatures. For example, the starting aid 44 could be a floating external conductive element, situated along the longitudinal center of the lamp assembly 36. The starting aid 44 may further include an electrical connection means, such as wire 46, to connect the starting aid 44 to electrical ground for even more improved low temperature starting conditions.
It is an advantage of this multiple array approach that lamp life can be effectively doubled if the electrical connections are such that both lamps are connected in a parallel discharge arrangement. That is, it is possible for one lamp to be on while the other lamp is off. With this type of arrangement, the light level would be equal to an equivalent twin tube lamp but only one-half of a quad lamp. The effective lamp life would be doubled. Many degrees of design flexibility are therefore provided, inherent to the multi-array approach.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that modifications and variations can be effected within the spirit and scope of the invention.

Claims

A multi-array twin tube lamp assembly comprising:
a. at least two twin tube lamps with independent electrode structures and discharge paths, each lamp capable of being attached to a base means and further being attachable to a lampholder means;

b. means for assembling the at least two twin tube lamps in close proximity to provide a plurality of individual lamps in close proximity.
A multi-array twin tube lamp assembly as claimed in claim 1 wherein the means for assembling the at least two twin tube lamps in close proximity comprises means for modifying the base means of each lamp.
A multi-array twin tube lamp assembly as claimed in claim 2 wherein the means for modifying the base means of each lamp comprises adhesive means for bonding the base means of each lamp in a desired configuration.
A multi-array twin tube lamp assembly as claimed in claim 2 wherein the means for modifying the base means of each lamp comprises mechanical connection means for attaching the base means of each lamp in a desired configuration.
A multi-array twin tube lamp assembly as claimed in claim 6 wherein the base means is a common base.
A multi-array twin tube lamp assembly as claimed in claim 6 wherein the base means is an individual base for each lamp.
A multi-array twin tube lamp assembly as claimed in claim 1 wherein the means for assembling the at least two twin tube lamps in close proximity comprises means for modifying the lampholder means of each lamp.
A multi-array twin tube lamp assembly as claimed in claim 7 wherein the means for modifying the lampholder means of each lamp comprises adhesive means for bonding the lampholder means of each lamp in a desired configuration.
A multi-array twin tube lamp assembly as claimed in claim 7 wherein the means for modifying the lampholder means of each lamp comprises mechanical connection means for attaching the lampholder means of each lamp in a desired configuration.
A multi-array twin tube lamp assembly as claimed in claim 7 wherein the lampholder means is a common lampholder.
A multi-array twin tube lamp assembly as claimed in claim 7 wherein the lampholder means is an individual lampholder for each lamp.
A multi-array twin tube lamp assembly as claimed in claim 1 wherein each of the plurality of individual lamps in close proximity has a separate lamp voltage.
A multi-array twin tube lamp assembly as claimed in claim 1 further comprising an external starting aid to facilitate starting at low temperatures.
A multi-array twin tube lamp assembly as claimed in claim 13 wherein the external starting aid comprises a floating external conductive element, situated along a longitudinal center of the lamp assembly.
A multi-array twin tube lamp assembly as claimed in claim 14 wherein the external starting aid further comprises an electrical connection means to connect the starting aid to electrical ground.
A multi-array twin tube lamp assembly as claimed in claim 1 wherein each of the lamps are externally connected in parallel to effectively extend lamp life.