FORM 2
THE PATENT ACT, 1970
(39 Of 1970)
&
THE PATENTES RULES, 2005
COMPLETE SPECIFICATION (See section 10, rule 13)
1. TITLE OF THE INVENTION
"Induction type Electrode-less Lamp"
2. APPLICANT(S)
1. Mahindra Hinoday Industries Limited
An Indian Company,
Bhosari Industrial Estate, Bhosari, Pune - 411 026, Maharashtra, India
2. Mohan S. Divekar
An Indian National
69, USHA, 15A Cross, 6th Main, Malleshwaram (W), Bangalore
3. PREAMBLE OF THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Title: Induction type electrode less lamp
Field of Invention:
The present invention is related to induction type electrode-less lamp. More particularly the present invention is related to electrode-less lamp that eliminates the radiation of electro-magnetic interference (EMI) from the lamp shell and operates at low frequency.
Background of the present invention:
Induction type Electrode-less lamps available in public domain so far is of two kinds, namely (i) internal electrode type, and (if) external electrode type. Though these lamps are termed as electrode-less, the reference to the term 'electrode-less' is to the way the ferrite cores excite an empty glass shell of the lamp by induction principle.
In interna] electrode type lamp, the exciting ferrite core is not usually visible to external world and is fully enclosed by the glass shell. This is extremely complex in construction and expensive too. These lamps are compact and operate at about 2.5 MHZ (Philips Q lamp and GEs's Genura lamp) and about 13 MHz (Mitsubhishi). But the radiated electro-magnetic interference (EMI) from this lamp is at this frequency and hence it interferes with the normal communication equipments. Hence these types of lamps could not be popularized.
In external electrode type lamp, for example OSARAM's Icetron, exciting ferrite core is fitted over the lamp shell and operating frequency is about 250 KHz. Prior art patents disclosing external electrode type lamp claimed that these lamps could operate from 50 to 1000 KHz for convenience. But the ferrite core size and the associated cost go so high if one tried to operate it at lower than 250 KHz. The commercially available lamps actually operate at about 220 to 500 KHz.

The drawbacks of these concepts are - these lamps radiate EMI at this frequency along with the light and hence likely even the harmonics will interfere with communication frequencies like medium wave radio frequency band. Further the magnetic core as well as many critical components in the electronics driving power to the ferrite core fitted on the lamp operate at this frequency of 220 to 500 KHz. Higher the frequency, higher the switching losses and lower the efficiency of the lamp and the lamp driver therein.
European patent No. EP0678900 describes an electrode-less lamp with an external conductive coating on a vitreous envelope for suppressing electromagnetic interference on mains that supply power to the lamp. The disadvantages of this invention are (i) it requires highly transparent coating which should not reduce the lumen output and thereby the efficiency of the lamp; [if] the coating has to be special material which is electrically conducting and optically transparent; (hi) the invention (particularly the coating) does not prevent generation of the high frequency itself and hence the problems related to in efficiency still exist, however, coating additionally degrades the performance further; and (iv) the degradation in transitivity of the optical coating also reduces lumen output life of the lamp - which otherwise has a longer life. This invention is specifically aimed at internal electrode type lamps which operate at 2.5 MHz and above.
American patent No. US4254363 educates on electrode-less coupled discharge lamp having reduced spurious electromagnetic radiation by attaching a strip (instead of some chemical coating) on the outside of the lamp. This solution further limits the surface area emitting the light and does not completely stop the radiated energy as between the wires. It further does not stop the electronics itself from operating at high frequency- and hence all associated problems still remain. This solution cannot be scaled down to lamps operating at 250 KHz because of dimensions (wave lengths are far higher at lower frequencies) issues.
Another American patent No. US5886472 talks about electrode-less lamp having compensation loop for suppression of magnetic interference by placing an

additional coil ring around the lamp in anti-parallel manner to cancel out the EMI due to the lamp. The disadvantage being, the coil further obstructs the light emitting surface and reduces efficiency. Further the coil also has to be driven from electronics and energy input has to be of same magnitude as in the lamp to completely cancel out the EMI issue. Thus, it again aggravates the problem and leads to inefficiency.
American patent No. US 6288490 discloses ferrite-free electrode-less fluorescent lamp wherein a phosphor coating is disposed on the inner surface of the envelope surface and a reflective coating is disposed on the inner surface of the area adjacent to the induction coil. Thus, it is attempting to do away with ferrite core fitted on the lamp. The disadvantage being the coupling of energy is in air in the absence of any magnetic material to couple energy from external coil to internal gas. The leakage of energy will be high and operating frequency goes higher to operate the lamp. Hence this will remain an academic exercise only. In addition it aggravates the problem related to EMI radiation and does not solve it.
To overcome these drawbacks, the invention described herein is proposed.
Objectives of the present invention:
The main objective of the invention is to provide a novel external electrode type electrode-less lamp.
Another objective of the present invention is to provide a novel induction type electrode-less lamp that targets on minimizing the radiation of electro-magnetic interference (EMI) from the lamp and improved efficiency of the lamp.
Still another objective of the present invention is to provide a novel induction type electrode-less lamp that does not interfere with existing lower frequency normal communication channels.

Still further object of the present invention is to overcome the drawbacks of the prior art concepts that targets minimizing radiation of EMI.
Advantages of the present Invention:
• The invention does not lead to generation of electromagnetic radiations in the most common lower frequency communication band of 100 KHz and above.
• It is a low cost solution to control electro-magnetic radiations.
• The invention works on low frequency in the range of 30 to 60 KHz.
• The invention does not interfere with existing lower frequency communication channels.
• The invention does not lead to degradation in light output / lumen efficiency.
• It has lower thermal switching losses thereby leading to longer life of the driver circuits and the lamp shell.
• The lamp shell operating temperature is lower thus leading to lower thermal load on the environment like air conditioning etc.
• The electronic components used in the lamp are easily available component operating at lower frequency.
• Lamp does not have to compromise on high power factor and low harmonics on the mains input side.
• The electrode less lamp of the present invention also eliminates the health hazards caused to human beings and living animals by the prior art lamps (that operates at high frequencies more than 100 KHz) as the lamp of the invention operates at low frequencies.
Brief description of figures:
Further objectives and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein,

Figure 1 shows layout diagram of the external electrode type electrode-less lamp in accordance with the present invention.
Figure 2 shows different embodiments lamp shells and cores fitted over it in accordance with the present invention,
Figure 3 shows diagram of the internal electrode type electrode-less lamp as another embodiment of the present invention
Detailed description of the present Invention:
Electrode-less lamp (ELL) is a low pressure gas discharge lamp which is of the same family of widely used linear tube lights and compact fluorescent lamps (CFL). It is well known fact that the lumen per watt efficiency of these lamps goes up when lamp operating frequency is around 30 KHz and thereafter it saturates. Hence any operation above 30 KHz is for convenience from another point of view and not to improve the lumen lamp shell efficiency.
Referring to Figure 1, the induction type electrode-less lamp (1) comprises of kick starting electronic driver (2), normal operation electronic driver (3), low pressure gas discharge light emitting tube / envelope (6), ferrite core (7) to kick start, ferrite core (9) for normal operation and communication modules (4), (8) and (10). The communication module (4) is the synchronizing link between kick start (2) and normal operation (3) drivers. The kick start driver (2) ignites the light emitting shell (6) at high frequency and normal operating driver (3) maintains the operating / running condition of the lamp shell (6) at low frequency. The kick start driver (2) and normal operating driver (3) are interconnected with each other through communication module (4) and they are housed in a suitable made driver box connected to the lamp shell (6). The communication module (4) exchanges the signal between these two drivers. Both the drivers (2) and (3) get the power from the main power source (5). The low pressure gas discharge envelope / lamp (6) is fitted with ferrite cores (7) and (9) by clamping. The ferrite cores (7) and (9) are soft and consists of two split halves (irrespective of its

shape] and clamped on the glass envelope [6] encircling it without any air gap. The material of clamping is non-magnetic and the position of the ferrite cores on the glass envelope is immaterial. The number of ferrite kick start driver cores and normal operation cores could be odd or even numbers. The ferrite core (7) is connected to the kick start driver (2) through communication module [8) and the ferrite core [9] is connected to the normal operating driver (3) through communication module (10). All these communication modules are basically wires of suitable current rating.
The kick start circuit (2) driving ferrite core (7) operating at frequency from 200 to 1000 KHz and the normal operating circuit (3) driving ferrite core (9} operating at frequency from 30 to 60 KHz are simultaneously turned on to begin with. The isolation between the two circuits is high impedance presented by a non-functional lamp to begin with. Based on the inputs received from kick start driver (2), the ferrite core [7] operates at higher frequency ranging from 200 to 1000 KHz for a fraction of second and ignites the envelope (6) radiating the light. As the envelope (6] radiates the light, the kick start driver (2} sends the signal to normal operating driver (3) through communication module (4) and activates it to operate at low frequencies ranging from 30 to 60 KHz. The ferrite core (9) mounted on the envelope (6) gets the input for normal operation at lower frequencies from the normal operating driver (3) through communication module (10). As soon as the normal operating driver (3) is activated, the kick start driver (2) automatically is deactivated.
The material requirement and other characteristics of both the ferrite cores are optimized to operate it without saturation at appropriate voltages and frequencies depending on the wattage of the lamp. The gas discharge lamp (6) has a negative resistance characteristics and voltage across the lamp drops when it ignites due to high energy it receives from the kick start circuit. During the running condition of the lamp, the lamp is sustained at the normal lower operating frequency of 30 to 60 KHz and the driver circuit (2) is put automatically into the hibernation state thereafter.

The invention disclosed herein ensures lamp operation closer to the phosphor lumen efficiency level without unnecessarily raising the operating frequency higher. The driver and operating circuits are similar but the inductive and capacitive components are tuned to operate differently. The kick start driver circuit operates for a fraction of second at the beginning only and hence does not lead to radiation of EMI as in the prior art concepts/cases. The kick start driver circuit is shut down automatically after the lamp starts normal operation. The kick circuit starts the lamp at high frequency in the range of 200 to 1000 KHz depending on the material of the ferrite core fitted on the lamp shell. The running or normal operating electronics operates at as low as 10 to 60 KHz in the driver as also the additional ferrite core fitted on the lamp.
The lamp and both the driver circuits operates at 10 to 60 KHz and hence all associated switching losses are lowered down which consequently leads to the improvement in efficiency. At the same time, it eliminates the source of high frequency radiation (EMI] without any reduction in lumen performance of the lamp shell [6].
The UV light generated inside the glass shell is converted to visible light by the coating of the phosphor on the inner walls of the glass shell. The efficiency of conversion of UV energy into visible energy saturates at about 30 KHz. Hence, the lower frequency limit of operation has been fixed at around 30 KHz and is not due to any limitation on the concept of invention suggested here. Similarly the upper limit of 60 KHz is selected only for minimization of switching losses and reduction of radiated EMI. However, the concept of invention can be extended to higher frequencies without limit as well.
There is absolutely no relation between kick starting frequency and running frequency. In accordance with the present invention, no relation means, kick start frequency could be anywhere from 100 to 1000 KHz and the operating frequency could be anywhere from 10 to 60 KHz.

The present invention neither uses any kind of chemical coating on the lamp shell nor coils with out of phase power input [as mentioned in various prior arts) on the lamp shell to cancel the EMI. Hence there is no degradation in lamp lumen output. The problem has been overcome by attacking at the root cause i.e. not having any section to operate at high frequency anywhere in this invention. Therefore, it leads to overall improvement in efficiency of the lamp.
The invention as described herein, involving kick starting at one very high frequency and then operating at very low frequency, can be scaled to be adopted to even the internal electrode type lamp. This adaptation would bring down its operating frequency to 50 KHz.
The prior art internal electrode type ELL lamps e.g. GENURA of GE and Q lamp of Philips are complex and operates at frequencies at about 500 KHz which still has a higher frequency interfering with medium wave radio band broadcasts. Therefore, the present invention can successfully be exercised for internal electrode type ELL as another embodiment of the present invention as disclosed in figure 3.
It should be understood that the present invention is not to be limited by the exact details of the illustrated embodiment. However, it is to be taken as the preferred example of the invention and that various changes may be resorted to by a person skilled in the art without departing from the spirit of the invention. Also, the terminologies used herein are for the purpose of description and should not be regarded as limiting.

We Claim:
1. Induction type electrode-less lamp comprising of kick starting electronic driver (2), normal operation electronic driver (3), low pressure gas discharge light emitting tube / envelope (6), ferrite core (7) to kick start, ferrite core [9] for normal operation and communication modules (4), [8] and (10), wherein kick start driver (2) and normal operating driver (3) are interconnected with each other through communication module (4); the said communication module (4) is the synchronizing link between kick start (2) and normal operation [3] drivers and exchanges the signal between these two drivers.
2. Induction type electrode-less lamp as claimed in claim 1, wherein the kick start driver (2) ignites the light emitting shell (6) at high frequency and normal operating driver (3) maintains the operating / running condition of the lamp shell (6) at low frequency.
3. Induction type electrode-less lamp as claimed in claim 1, wherein the low pressure gas discharge envelope / lamp (6) is fitted with ferrite cores (7) and (9) by clamping.
4. Induction type electrode-less lamp as claimed in claim 3, wherein the ferrite cores (7) and (9] are soft and consists of two split halves (irrespective of its shape) and clamped on the glass envelope (6) encircling it without any air gap.
5. Induction type electrode-less lamp as claimed in claim 3, wherein the material of clamping is non-magnetic and the position of the ferrite cores on the glass envelope is immaterial.
6. Induction type electrode-less lamp as claimed in claim 4, the lamp and both the driver circuits operates at 10 to 60 KHz and hence all associated switching losses are lowered down which consequently leads to the improvement in efficiency.

7. Induction type electrode-less lamp as claimed in claim 6, wherein the said lamp eliminates the source of high frequency radiation (EMI) without any reduction in lumen performance of the lamp shell (6).
8. Induction type electrode-less lamp as claimed in above claims, wherein there is absolutely no relation between kick starting frequency and running frequency.
9. Induction type electrode-less lamp as claimed in claim 8 wherein kick start frequency could be anywhere from 100 to 1000 KHz and the operating frequency could be anywhere from 10 to 60 KHz.
10. Induction type electrode-less lamp as claimed in claims 1 to 9 substantially described hereinbefore in the specifications and drawings.