ANNEXUREI

COMPLETE SPECIFICATION

TITLE:

LED based tube light to retrofit in the conventional fluorescent tube lighting fixture - 'LED tube'

1) PRODUCT NAME:

LED based tube light to retrofit in the conventional fluorescent tube lighting fixture - 'LED tube'

2) OWNER OF PRODUCT AND ADDRESS:

Owner:
MIC Electronics Limited
A Public Limited Company

Address:
A - 4/11, Electronic Complex, Kushaiguda, Hyderabad - 500 062 INDIA.
Email: info@mic.co.in
Tel:+91 40 27122222
Fax:+91 40 27133333

Field of research:

LED lighting devices as retrofits in the conventional tube lighting fixtures

3) OBJECTS OF THE INVENTION:

The present invention deploys Light Emitting Diodes (LEDs) as energy efficient light sources enclosed in a standard 4ft long tube made up of aluminium extruded base and a PMMA diffuser casing, the two ends closed with end caps with pins for use as retrofits in the conventional tube light fixture.

4) PRIOR ART:

Fluorescent tube lights, operating in conjunction with starter and choke are in existence. The typical power ratings are 40 W and 36 W with slim tubes for the popular tube length of 4 ft and the tube lights work on the principle of electrical arc discharge.

LED based tube lights have been discussed in the patent application Patent No. 2009101044 IP Australia.

The co-pending patent application no. 2713/CHE/2010 by the inventor discloses the construction and operation of a 2ft tube light - 'LED based extendable and configurable lighting system / DC or solar operated tube lights'.

5) SHORTCOMINGS OBSERVED IN PRIOR ART:

A fluorescent tube light emits white light through an electrical discharge process - during which there is flickering and radiation - which is harmful to human eye or body. A choke (ballast) and a starter are used to trigger the process, there is a time lag for the light to switch ON; failure of any of these parts results in light failure and needs replacement. The life of the fluorescent tube itself is short and unreliable; dark bands are formed on degradation; there is need to replace the light tube also frequently. The choke and starter increase the initial cost of the fixture. The power consumption is a concern which needs to be addressed for conservation of the scarce and costly grid power. The light source is Omni-directional and there are light losses in the undesired directions or there is need to use reflectors with partial success in directing all the light from the undesired directions to the desired directions. Mercury is a poisonous material disposal of which is an ecological issue.

6) PROPOSED INVENTION

The proposed LED tube lights overcome these drawbacks of conventional fluorescent tubes with additional advantages of the LED technology viz. significant savings in power consumption (about 50%), instant switch ON, no flicker, long life, directed light output with no losses, relatively low maintenance, no pollution and no issues in disposal of the waste. Replacement costs of choke and starter are avoided as they are not needed in the proposed retrofit.

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

The present invention of the LED based retrofit tube light consists of a lower layer housing made up of metallic base and upper layer casing made up of PMMA diffuser sheet This tube light is of 4ft (120cm) in length and its diameter is about 1.1 Sin (3cm). The tube weighs around 453grams. As this LED tube light is a retrofit, the conventional tube light can be replaced by the LED tube.

In the LED tube light, 117 LEDs are mounted in a row to achieve the luminous flux to the level of 1200-1500 lumens. The total power consumption of the circuit will be around 15 - 18W. The LED tube light consisting of two end caps, is having power supply at one end and driver at the other end.

The following paragraphs provide details of the construction and operational features:
1. Construction
2. Block schematic of LED tube light luminaire
3. Targeted Specifications
4. Diagrams / photographs of LED tube
5. Illustrative procedure for a retrofit light fixing in the existing or new fixture

1. Construction

The Tube light consists of

• An Aluminium extruded base
• A PCB containing LED strings in requisite numbers
• A Power supply assembly
• A Driver Assembly
• A PMMA diffuser casing
• Two end caps at both ends
• 2 pin covers on the end caps

The construction is depicted in the diagrams of the front view and the exploded view of the LED Tube light in section 4.

2. Block Schematic of LED tube light:

The block schematic is organised into three sub-blocks - 18W VFPFC PCB, 18W TUBE DRIVER PCB and LED PCB.

18WVFPFCPCB:

The input grid power supply is of the universal range that is from 90V-265V. In this diagram first block is Input Line filter which is used as an EMI filter. It isolates the mains supply from high frequency switching noise at the output.

Second block is the bridge rectifier, which provides the function of rectification. The output from the bridge rectifier is sent to passive PFC circuit.

Third block is the passive PFC circuit, which performs power factor correction which maintains the power factor above 0.9. It also acts as a filter circuit, which reduces the AC ripple and provides the DC voltage to the BUCK regulator.

18W TUBE LIGHT DRIVER PCB:

Constant current LED

The output from the passive PFC circuit is then fed to high voltage constant current LED driver. This circuit maintains constant current to LED array irrespective of the input line voltage changes and load variations.

In this block diagram first block is the buck regulator, which reduces the DC voltage to the required level. The constant LED current is maintained by an IC through feedback circuit by sensing the LED current and comparing with reference value. IC's internal intelligence controls the switching times of the tube light

Second block is the constant current LED driver, which maintains the feedback loop with reference to the output of the buck regulator and provides a constant current to the buck regulator. The output from the buck regulator is given to the input of LED PCB.

LED PCB:

From Tube light
Driver PCB

All the 117 LEDs are connected in series as 3 LED strips totally forming the LED tube light. Total wattage of this tube light is around 15 -18W.

3. Targeted Specifications:

Parameter Specification
Power Consumption 15-18 Watts
Electronics Efficiency >85%
Light Source White LEDs
Input Voltage 90 to 150VAC
180to265VAC
Line Frequency 50 / 60Hz
Luminous Flux 1200 -1500 lumens
Illumination at 2mtrs distance 130lux
Viewing angle 120°
Color Temperature 6400K (Cool White)
Lifespan > 50,000 Hours
Operating Temperature -10°C to 50°C
Storage Temperature -20°C to 85°C
Construction Impact resistant plastic with integrated heat sink
Physical Dimensions Overall Length - 4 Feet (120 cm);
Diameter- 1.18in (3 cm)
Weight 1.2 lbs (453 grams)
Base Types Bi Pin T8, T10, T12 Compatible
For MIC Electronics Limited

4. Diagrams / photographs of LED tube:

1: Front view of the LED tube light

2: Exploded view of the LED tube light

Inductive Ballast
LED TUBE LIGHT
STARTER

3: Wiring Diagram of the LED tube light

5. Illustrative procedure for a retrofit light fixing In the existing fixture / New fixture

Retrofit Installation:

It is a simple process involving just 3 steps to install the retrofit LED tube light. The existing fluorescent tube light is removed. The Choke or the ballast is short circuited or removed. The starter is removed or made open then the LED tube light is installed in the place of the fluorescent tube light.

New Installation
Directly Install MIC LED Tube Light in to the fixture

The LED tube light can be directly installed in a new fixture (without the starter & choke) in a single step.

We Claim

1. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of comprising of:

 LED PCB
 Tubular shaped PMMC diffuser sheet
 A Power Converter (AC-DC)
 A driver Circuit
 Two end Caps and
 Two end pins at each end.

2. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the device is designed for grid based indoor operation.

3. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the LED tube light is the replacement for the conventional 4 feet fluorescent tube light and results in low power consumption with highly directed light output and a long life.

4. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein 117 LEDS are connected in series. Power supply and LED driver circuit are housed at the two sides of the fixture inside the fixture inside the two end caps. The number of LEDs is decided based on the type of LED and the wattage requirements.

5. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the choke of the fluorescent tube light is either shorted or removed and the starter terminals are open or removed.

6. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the lower layer housing is made up of metallic base and the upper layer casing is made up of a PIVIMA diffuser sheet.

7. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the end caps provide space needed to cover all the circuitry and only the tube is visible outside. There is no need to replace the tube light often because of the longevity of LED tube light.

8. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the driver circuit maintains the constant current to LED array irrespective of the input line voltage changes and load variations.

9. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the input termination block in the power supply provides the short circuit and over voltage protection for the input fluctuations.

10. LED based tube light to retrofit in the conventional fluorescent tube lighting fixture of claim 1 wherein the device may be designed with variants like DC operated; 2ft length; and clear transparent casing in place of the diffuser.