WO2006041410A2

WO2006041410A2 - Rugged light bulb

Info

Publication number: WO2006041410A2
Application number: PCT/SG2004/000332
Authority: WO
Inventors: Peng Seng Toh; Chin Chai Tay
Original assignee: Grenzone Pte Ltd
Priority date: 2004-10-12
Filing date: 2004-10-12
Publication date: 2006-04-20
Also published as: WO2006041410A3

Abstract

The invention relates to a light bulb that has built in support that increases the ruggedness and uniformity of the U-shape fluorescent tubes (11). The said light bulb is able to take a large amount of shock and vibration due to the fact that the U-shaped fluorescent tubes are being secured onto the support. Cover is provided to protect against direct impact and hence further improves its ruggedness. The light bulb is cool and safe to handle and can be used in close proximity to the user without being fear of burnt or breakage. The said light bulb is easily manufactured and assembled.

Description

Description Rugged Light Bulb

[1] This invention relates in general to light bulbs with improved ruggedness, safety, long lifespan and energy efficiency.

[2] Background

[3] There are many different types of light bulb with standard sockets such as Edison socket are available commercially. The first generation of light bulb invented by Edison was tungsten incandescent lamp that converts heat to light. Due to the need to improve energy efficiency saw the emergent of tungsten halogen light bulb. Although work on the same principle of heat conversion to light, the tungsten halogen light bulb has higher efficiency and longer lifespan. More recently, compact fluorescent lamp or commonly known as CFL, which has even higher energy efficiency become widely adopted. Compact fluorescent lamps, CFL, are packaged with one or multiple U tubes to form a single light bulb with standard sockets. These three different types of common light bulb are easily broken as they are manufactured using glass. In¬ candescent tungsten and tungsten halogen lamps are extremely hot during operation and can easily hurt a user who contacts with the light bulb. The compact fluorescent lamps, although less hot in comparison with tungsten lamps, are also of harmful temperature. These lamps are deployed at location where they are not easily touched.

[4] A typical compact fluorescent lamp consists of one to several U tubes, a shell that houses the electronic ballast, a socket, and an optional cover either fully transparent or diffuse to protect the tubes.

[5] In view of the shorting comings of the existing light bulbs especially in terms of life span and safety, solid state lights such as the light emitting diode (LED) manufactured in the form of light bulbs are potential alternatives. LED light bulbs have many mechanical advantages and also capable of operating at low voltage. However, LED does not have the comparable efficacy and cost competitiveness of CFL. LED also suffers from having a less preferable emission spectrum although blue LEDs have been successfully commercialized.

[6] Cold cathode fluorescent lamps have many advantages such as comparable efficacy to CFL but with longer lifespan and cool operating temperature. However, most of the existing cold cathode lamps available presently are mainly used for backlighting of electronic displays and emergency lights. They are embedded within other electronic applications such as notebook, game console and so on. Cold cathode fluorescent lamp is still not widely used as an independent light bulb with standard socket to provide il¬ lumination.

[7] Both cold cathode fluorescent lamps and compact fluorescent lamps require the use of external reflector to achieve uniform luminaries. The U shape cold cathode and compact fluorescent lamps usually appear to have a dark area in the middle of the U. Almost no CFL or CCFL light bulb is designed with built-in reflector.

[8] There is therefore a need to provide a light bulb that is compact, energy efficiency, rugged and safe for general illumination application.

[9] A survey of prior arts reviewed that most of the inventions are related to tube design such as tube shapes and mounting. Prior arts on compact fluorescent lamp reflectors are mainly external reflectors.

[10] US6059593 describes an invention that is an assembly for use with a compact fluorescent lamp includes a socket and an adapter. This invention addresses the com¬ patibility of different shapes of CFL tubes with different sockets.

[11] US6739737 discloses an invention that provides a lamp body or reflector for a compact fluorescent spot and flood light source. The reflector is external to the compact fluorescent tubes.

[12] Summary of Invention

[13] One object of the present invention is to provide a light bulb with increased ruggedness and yet has the energy efficiency of the fluorescent lamps, including cold cathode and compact fluorescent lamps such that they can better handle shock, drop, impact and vibration.

[14] Yet another object of the invention is to increase the uniformity of the luminary pattern of the U tubes fluorescent lamps.

[15] According to the present invention, the rugged light bulb consists of a support column serving as a support to at least one U shaped fluorescent tube and concurrently serves as a reflector to increase the uniformity and luminous intensity of the light output. The support column is positioned in the void space of the U tubes and hence does not increase the overall size of the light bulb. The support column fixates each of the U lamp tubes at three positions hence increasing its stability. Being positioned within the U shaped fluorescent tubes, the support column serving as a reflector is internal and built-in to the light bulb.

[16] Brief description of drawings

[17] FIG. 1 shows the exploded view consisting of the primary parts of the rugged light bulb.

[18] FIG. 2 shows the support column.

[ 19] FIG. 3a illustrates the assembly of one U shape fluorescent tube with the support column.

[20] FIG. 3b illustrates the assembly of two U shape fluorescent tubes with the support column.

[21] FIG. 4 is a cross sectional view of the support column and U shape fluorescent tubes to illustrate the support column reflects the light from the U shaped fluorescent tubes that achieves better uniformity.

[22] Description of a Specific Embodiment

[23] The present invention is in general a fluorescent light bulb with increased ruggedness, compactness and improved uniformity.

[24] The light bulb consists of at least one U shape fluorescent tube 11 , a support column 20, a lamp cover 52, a shell 50, a shell cover 51, electronic ballast 60 and a socket 53.

[25] The light bulb consists of a support column 20 with groves 20a on one end and a base 20b on the other end. The groves 20a on the support column 20 are matched to the size and shape of the curved portion 1 Ia of the U shape fluorescent tubes 11 such that it can be firmly assembled to another. The base 20b of the support column 20 has a plurality of holes 20c to allow the U fluorescent tubes 11 to be inserted and thus firmly secured. The terminals 1 Ib of the U shape fluorescent tubes extend slightly beyond the support column base 20b and are connected to the electronic ballast 60 housed within the shell 50. Adhesives are further used to bond the U tubes 11 to the support column 20 at the three interlocking positions namely the curved portion 11a with the groves 20a; and somewhere near the terminals with the holes 20c of the base 20b. Without the three positions of the U fluorescent tubes 11 adhering to the support column 20, the U shape fluorescent tubes 11 will be susceptible to breakage due to shock and vibration.

[26] The support column 20 can be easily molded, such as injection molding, using a variety of engineering plastics to achieve manufacturability and hence cost ef¬ fectiveness. The material selected to manufacture the support column 20 is preferably reflective and yet sufficiently diffuse to improve the uniformity of the luminous pattern. The cross sectional body of the support column 20 is largely circular and its diameter is slightly bigger than that of the U shape fluorescent tube 11. It is recommended that the diameter of the support column 20 be 1.5 to 5 times that of the U shape fluorescent tube 11.

[27] The lamp cover 52 provides protection to the U shaped fluorescent tubes 11 housed within such that it will not be subject to direct impact and therefore breakage. The lamp cover 52 can also provide the desired luminaries by selecting its optical property such as making it transparent, diffuse or tinted. Clear thermoplastic materials that can be molded and optical property modified are highly recommended. Different shapes of lamp cover 52 with different surface texture can also be molded not limited to regular shapes with smooth surface.

[28] The U shaped fluorescent tubes 11 do not need to be shaped exactly like a 'U' as long as they are smoothly bent to form a loop. It is highly recommended to use cold cathode fluorescent tubes instead of the compact fluorescent tubes if the light bulb is largely enclosed by the lamp cover 52. Cold cathode fluorescent tubes give off much less heat than the equivalent compact fluorescent tubes during operation. Provision of ventilation on the lamp cover 52 and the shell 50 to release the heat generated by the electronic ballast 60 and the fluorescent tubes 11. In the case of compact fluorescent tubes, large ventilation opening should be provided because of the high amount of heat generated.

[29] The present invention can be extended to more than 2 U shaped fluorescent tubes il¬ lustrated in the accompanied drawings. For example, 3 U shaped fluorescent tubes mounted on the support column spaced at 60 degrees with respect to another are also applicable without sacrificing the ruggedness and compactness. In practice, other types of socket 53 not limited to Edison socket can be used.

Claims

[1] The rugged light bulb comprises at least one largely U shape fluorescent tubes, a support column, lamp cover, shell, socket and electronic ballast; each of the said

U shape fluorescent tubes is adhered to the support column at three positions including one at the curved portion and two near the terminals. [2] The rugged light bulb as claimed in claim 1 wherein the support column has a largely circular cross-sectional shape and is largely reflective. [3] The rugged light bulb as claimed in claim 2 wherein one end of the support column has groves that match the shape and size of the U shape fluorescent tubes such that they firmly assembled with one another. [4] The rugged light bulb as claimed in claim 3 wherein one end of the support column has a base with a plurality of holes for the terminals of the U shape fluorescent tubes to be inserted and adhered. [5] The rugged light bulb as claimed in claim 4 wherein the support column is a molded thermoplastics part. [6] The rugged light bulb as claimed in claim 5 wherein the lamp cover encloses the assembly of the U shape fluorescent tubes and the support column. [7] The rugged light bulb as claimed in claim 1 wherein the U shape fluorescent tubes are cold cathode fluorescent lamp tubes. [8] The rugged light bulb as claimed in claim 1 wherein the U shape fluorescent tubes are compact fluorescent lamp tubes.