IMPROVED T5 STREET LIGHT FIXTURE FOR MORE

UNIFORMITY OF LIGHT Field of the invention: The present invention IMPROVED T5 STREET LIGHT FIXTURE FOR MORE UNIFORMITY OF LIGHT relates to a lighting apparatus, in particular to a lighting apparatus for street lighting purposes. The invention maybe considered to be in the field of energy efficient lighting for street lighting with T5 florescent lamps or LED lamps, but not limited thereto. T5 being very small in diameter, it is easier to make such reflectors that can direct the light in the desired direction.

Background of the invention: Fluorecent luminaires have become increasingly popular in recent years for use in street lightning as they have a comparatively low brightness or glare when related to conventional small source luminaires, such as mercury vapor lamps and incandescent lamps. Recently, T5 fluorescent lighting has been established as the most visible and energy efficient light source. It can be used to substitue HID lighting to bring saving in energy.

An object of the invention is to provide a lighting unit in which the maximum amount of light is dispensed downwardly into the area about the light support. Still another object is to provide a lighting unit in which the light from the lamps are reflected downwardly and

outwardly and is thus prevented from being dispersed above the lighting unit, where it does no effective good. A still further object is to provide a lighting unit in which the light which is thrown downwardly from the lamps are reflected outwardly away from the supporting post along the road for uniform lighting.

Lighting fixture having a colonical appearance have been popular for some time for purpose such as illumination of drivers, walks and patios of private residences and the like and particularly recently have also become popular for use along public ways.

A further object of the invention is to provide a lightning fixture of the character descibed which incorporates a reflector, which can be easyily cleaned after opening the cover.

Hence, the use of T5 & LED is fast increasing. LED, or light emitting diode is also a light emitting source, whose effϊceiency is very fast increasing. The LED has got the property of emitting light in a particular defined angle & so, it is easy to focus the light in a particular direction. Street lightning is a major energy consuming force so, to make is energy efficient intensity of light is maximized. The intensity of light is inversely propostional to the square of the distance. Now the center between two consecutive street light poles, which are 100 feet apart, is about 50 feet away from each pole. Hence, dark sports are normally observed at this center beteen two consecutive street light poles so, the objective of the instant invention

is to minimize these dark sports and provide more uniform lightning along the length of the road and to make the fitting electrically durable against voltage fluctuations and neutral fault the present invention is provided with alternative of the cabinet as well as the mirror optic reflector to provide more uniformity and to radiate the heat generated by the lamps to the ambience. The present invention is provided to satify the criteria in either an open type of cabinet or a dust proof and water proof cabinet, should be able to withstand thermal stress. The thermal stress is created in a dust & water proof cabinet since the lamps are totally enclosed by a protective cover. Due to the extra heat, light output decreases & may also shorten the life of the T5 lamps so, the object of the invention is dissipate the heat generated from the lapmps to the atmosphere.

Details Description of the invention :

The present invention is described with specific and greater clarity with reference to following drawings:

Fig. 1 represents the light output of conventional street lights

Fig. 2 represents the light output of present invention street lights Fig. 3 represents the three dimensional view of reflector

Fig. 4 represents the three dimensional view of cabinet

Fig. 5 represents the front view of T5 Lamps

Fig. 6 represents the cover for protecting main terminal from water

Fig. 7 represents the cross sectional view showing main reflectors, additional reflector(12) and they consisting with respect to lamps and circuit enclosure.

Fig. 8 represents the complete lightning fixture

Fig. 9 represents the cabinet with louvers

Fig. 10 represents the circuit diagram for present invention lighting fixtures.

The present invention consists of cabinet, sieve, exhaust fan, mains terminal, enclosure with circuit as shown in Fig.10 & holders, reflectors, lamps, acrylic enclosure or louvers, pole mounting, cover for main terminal.

In the present invention as shown in Fig. 1 and Fig. 2 comparison between the light output of conventional street lighting device and the present invention street light device is provided. Fig. 2 shows how the more uniform lightning coverage (3) along the road and to minimize the dark spots (2) normally observed near the centre between two consecutive street light poles (1. One or more T5 lamps (11) as shown in Fig. 5 are situated near the center of the reflector as shown in Fig.3. The reflector is made of high quality anodized aluminum reflector sheet, or any other material coated with a highly reflective surface (14) layer. The reflector (13) has a horizontal base as the center portion of the reflector (13) and one or more T5 lamps (11) are situated along the base of the reflector (13) as shown in Fig. 7.

The reflector has wings (4) as shown in Fig. 3 on both sides which make a downward angle of around 10 to 45 degrees with the base (5).

This angle serves a three fold purpose: First, protects light from being

directed in the upward direction, secondly reflects maximum light away towards around the center between the two poles(l), which is the farthest distance from the poles(l) as shown in Fig. 2. Thirdly, the wings of the reflector overlap along the part of the cabinet described below & the heat generated by the lamps is dissipated through the reflectors to the cabinet body & then to the surrounding air outside.

The reflector (13), lamps & circuit as shown in Fig. 10 enclosure is arranged such that the reflector (13) being near to the lamps absorbs the heat from the lamps and also shields the circuit from the heat of the lamps. Additional reflector (12) of inverted "V" or twin parabolic shape, are placed just below the lamps as shown in Fig.8. These additional reflectors (12) block the excessive redundant light in the exactly downward point below the pole, which is the shortest distance and directs the light outward, more towards the center between poles

(1).

The cabinet is shown in Fig. 4, which is made of aluminum or other sheet which radiates the heat of the lamps to the ambience. The cabinet is enclosed by a transparent cover as shown in Fig. 6, to make it dust and water proof, with the help of gasket lining fixed at the border of the fixture. The louvers are shown in Fig.9. The recessed center portion of the fixture contains the circuit as shown in Fig. 10, enclosure along with the lamp holders. From the center, cabinet flanges (6) are extended in a slope in such a way that the wings of the reflector (13) are in close contact with the flanges (6). The heat of the

lamp is radiated to the reflector (12) & the reflector in turn radiates the heat to the cabinet body, which further radiates the heat to the ambience.

The cabinet is made in such a way so as to minimize the metal parts needed to hold the circuit enclosures & lamps, so as to keep it light in weight. The entry of the main cable can be a conventional side entry or for more mechanical holding strength, the pole(l) can remain on the top of the fixture & the entry of the mains cable can be from the top with proper enclosure, to protect the main terminal connector from water and to let it appear sleek & aesthetic.

A slot or slots are opened out in part of the bottom metal portion of the cabinet and sealed with a sieve/filter(8) so, that if at all water collects in the fixture due to a manufacturing defect, it can easily drain out from the sieve(8) due to gravity. The sieve (8) is made of such material that water can drain out but dust & insects cannot sneak in. The sieve (8) also helps in radiating the heat generated by the lamps, to the ambience. An exhaust fan (7) is fitted adjacent to the sieve (8) for better heat emission. The primary object of this invention is to provide improved street light fixture, which is dust & water proof, gives more light & optimum utilization of light, thereby minimizing the dark sports(2) & which has the capacity to radiate the heat generated by the lamps to the ambience.

There may be as many reflectors as there are the fluorescent lamps, so that each lamp will have its own reflector. The reflector is designed and positioned in such a way that maximum light is transmitted at 30 to 60 degrees angle away from the downward direction. The lamps & reflectors are positioned in such a way that half the number of lamps throw maximum light toward one side of the pole(l) along the length of the road, while the remaining lamps throw maximum light towards the other side of the pole(l) along the length of the road. The reflector, here too is made of anodized aluminum reflector sheet, or any other material coated with a highly reflective layer. The cross sectional profile of the reflector can be a parabolic or radial type, or simply a flat surface bent to form two wings on each side, making an angle of 30-60 degrees with the center. This fixture may have a transparent cover to make it dust and water proof, but to dissipate the heat to the ambience, it can have louvers or mesh instead of transparent covers for air circulation and for protection of lamps. For the purpose of bringing uniformity of light along the road multiple LEDs is used in place of T5 lamps. LEDs have definite angle of radiation of light and the luminous flux is so controlled that exactly downward light is minimized, but the light falling near the center between two consecutive poles(l) which is an angle of 20 to 60 degree from the vertical axis of pole, is maximized. This can be done without reflectors.

Summary of the invention

The invention has been described for its use in street light, it can also be used in indoor lighting, industrial lighting and medium or high bay lightning to maximize energy by providing uniform lightning. Mounting of the fixture can be pole(l) mounting, reflective surface(14) mounting, recessed mounting or screw mounting with appropriate changes in mounting facilities depending upon the application.