3) OBJECTS OF THE INVENTION:

The present invention is an application of Light Emitting Diode (LED) technology in Troffer lights operating on grid power for office, commercial and home lighting; it is a direct replacement for recessed fluorescent Area lights. The main objective of the present invention is deployment of LEDs as light sources fully exploiting the technological advantages - Low power consumption, long life with minimal maintenance and reduced environmental pollution.

4) PRIOR ART:

Troffer lights are in existence which deploy fluorescent / CFL light sources. LED Troffer light has been discussed in the Patent Application No. US 7,645,052 B2, wherein LED Ceiling tile combination and ceiling tile is described.

5) SHORTCOMINGS OBSERVED IN PRIOR ART:

The commercial Troffer lights employ Fluorescent / CFL tubes as light sources with the short comings of poor efficiency, flickering, relatively short life, burnouts with associated replacements and environmental pollution.

6) PROPOSED INVENTION

LED Troffer lighting systems overcome the above concerns.

These employ LED light sources and an effective convection cooling system for driving away the heat generated by LED light sources.

LED Troffer lights produce constant and uniform lighting without any flickering;

consume less power compared to fluorescent lamps; last longer (about 50,000hrs) with minimal maintenance.

The present invention of LED recessed Troffer light also provides light output in different colours like cool white or warm white using LEDs of appropriate colour temperatures.

7) APPLICATIONS OF LED TROFFER LIGHTS:

• Office and home lighting
• Star hotels, Clubs and Farm houses / resorts
• Shopping Malls, Retail Stores
• Theatres, Auditoriums
• VIP chambers

8) DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

The present invention of the LED Troffer light (Fig:4) is a powder coated body of 2ft X 2ft square made up of CRCA metal. Power supply unit works with the AC input voltage; converts it into DC and drives the LED light sources. The LEDs are assembled in a linear order, three LED strips3 are mounted on the heat sink of the fixture. The front panel1 of the fixture is fitted with the reflector and the diffuser sheet2 which are arranged for converting the beam angle of the LED light source thereby increasing the intensity and uniformity of the light output. The heat sink is made of Aluminium metal which is fitted on the casing4 to cool the LEDs, driving away the heat generated at the light source.

The unit is designed for assembly of 45 or 30 LEDs achieving power output of 45W or 30W (small variations in power rating can be realised through manipulating the drive currents); 2ft X 2ft size; colour of the light can be varied between warm to cool white with proper selection of LEDs with suitable colour temperatures. Other sizes and shapes like 1ft x1ft, 2ft x 4ft, 1ft round with relevant wattages can also be considered within the scope of this invention.

The lighting unit is installed in the low roof / gridded false ceilings by means of clamps with the front panel in plane with the ceiling. Power is drawn from the nearest access points made available in the ceiling.

The following sections provide details of the construction and operational features:

1. Construction
2. Block schematic of the Recessed Troffer light
3. Targeted Specifications
4. Diagrams / photographs of LED Troffer light

1 .Construction

The Troffer light consists of

■ Front panel
■ Diffuser sheet
■ Reflector
■ White powder coated CRCA casing
■ Power supply unit
■ LED strips (MCPCBs) fitted on the casing along with heat sink

The construction is depicted in the exploded view of the Troffer light in section 4.

2. Block Schematic of Recessed Troffer light

The power supply section accepts input in the range of 150V - 265V AC. EMI / RFI line filter prevents high frequency noise. It filters out the noise generated from the load end and ensures its non - interference to the source side.

Input bridge rectifier rectifies the sine wave and provides the pulsating D.C as its output. The output from the bridge rectifier is sent to the single stage Power Factor Control (PFC) / FLY BACK converter.

Single stage PFC / FLY BACK converter performs power factor correction and maintains the power factor between 0.9 and 1 in order to boost or buck the voltage level as required. It also provides isolation between input and output.

Out put rectifier & filter rectifies the switching signal and filters the ripple components. It ensures sufficient DC voltage for LEDs.

For MIC Electronics Limited

CVCC (Constant Voltage Constant Current) feedback circuit provides constant driving current for LED strings. It also provides output over-voltage protection. Input section is electrically isolated from the output section and it is optically connected by using up to couplers (it provides isolation up to 5KV for 1min).

LEDs are mounted on the MCPCB. This PCB is electrically isolated and thermally conducting. It transfers the heat generated in LEDs to the metallic casing through a heat sink for natural cooling.

3. Targeted Specifications

8) CLAIMS:

We Claim the following:

1. An LED based Troffer lighting system comprising of:
• Powder coated CRCA casing of 2ft by 2ft size
• MCPCB strips (with LEDs mounted) affixed inside the casing along with aluminium heat sinks
• Front panel assembled with a reflector and a diffuser sheet (Secondary Optics)

2. An LED based Troffer lighting system of claim 1 wherein the device is designed for indoor lighting.

3. An LED based Troffer lighting system of claim 1 wherein the LED light sources are arranged in the form of linear strips (up to 3) with 10/15 LEDs each for meeting the illumination requirements of the target area.

4. An LED based Troffer lighting system of claim 1 wherein the LED strips are affixed on the heat sink for effective heat transfer from the light source to protect the LEDs for longer life,

5. An LED based Troffer lighting system of claim 1 wherein the reflector and the diffuser sheet are arranged for enhancing the light intensity and uniformity eliminating glare and eye discomfort.

6. An LED based Troffer lighting system of claim 1 wherein an effective natural convection cooling system ensures that the heat generated from the light source is driven away to the atmosphere.

7. An LED based Troffer lighting system of claim 1 wherein the power consumption is less compared to conventional lighting fixtures with Fluorescent and CFL lamps.

8. An LED based Troffer lighting system of claim 1 wherein the power supply has built-in short-circuit and over-voltage protection.

9. An LED based Troffer lighting system of claim 1 wherein the unit is designed for a basic set of targeted specifications like 2ft X 2ft size, 45W / 36W / 30W with provision to realise small variations by manipulating the drive currents; and the colours can range from warm white to cool white with proper selection of LEDs with suitable Correlated Colour Temperature (CCT). Other sizes and shapes like 1ft x1ft, 2ft x 4ft, 1ft round with relevant wattages can also be considered within the scope of this invention.

10. An LED based Troffer lighting system of claim 1 wherein the unit is intended for easy installation in low roof ceilings at a height of 2.8 meters for effective illumination.