FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A luminaire and highly efficient coating system for the luminaire with improved light output thereof
APPLICANTS
Company Crompton Greaves Limited, CG House, Dr Annie Besant Road. W Mumbai 400 030. Maharashtra, India, an Indian Company
INVENTORS
D'Melo Dawid. Chaudhari Lokesh, Jaiswal Rajendar and Kumar ICapil of Crompton Greaves Ltd, AMPTC, CG Global R&D Centre, Kanjur (E), Mumbai 400042, Maharashtra. India; all Indian Nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
The invention relates to the field of luminaires and their reflective coatings.
The invention relates to luminaire with enhanced light output ratio.
The invention particularly relates to a highly efficient coating system for a luminaire and
a method of the coating of a luminaire with the coating system thereof to enhance the
light output ratio.
BACKGROUND OF THE INVENTION:
Luminaires are designed to produce a pre-determined light distribution pattern in an area that is to be illuminated. Luminaires generally consist of a light source or lamp, a reflector for directing the light, an aperture (with or without a lens), an outer shell or housing for lamp alignment and protection, an electrical ballast, and connection to a power .source. Mostly, the reflectors diffuse reflectivity to redirect the light emitted by the luminaire. The light output ratio of the luminaire is the ratio of quantity of the light generated by the light source.
Many luminaires incorporate reflectors to increase the efficiency of their light output. Reflectors can be formed in a variety of shapes and sizes and are typically designed and oriented to provide optimized light distribution for particular applications. Accordingly. they may be symmetrical or asymmetrical depending on the desired light output distribution. The most common reflector for a luminaire is a symmetrical reflector. Because the reflector surrounds the lamp to reflect the light, it is usually fashioned from a single piece of material or is fashioned from multiple pieces of material to constitute a single reflector.
The reflector surrounds the lamp and reflects the light downward in a substantially round distribution pattern. Because the lamp is almost always placed within the volume defined by the reflector, the wide angle illumination of a lamp and reflector combination is limited to the light that is directly emitted from the lamp and/or is reflected by the reflector and then passes below the edge of the reflector or luminaire body without contacting any part of the luminaire. This limitation results in a relatively limited wide angle light distribution pattern, below the luminaire. To an extent, this difficulty can be addressed by lowering the lamp within the reflector volume or raising the reflector with

respect to the lamp. However, this can result in increased glare and eye strain. Additionally, in having a reflector that surrounds the lamp some of the light is reflected multiple times within the reflector thereby reducing the efficiency of the luminaire, Further, some of the light is reflected back through the lamp itself which can result in reduced lamp life and reduced efficiency.
While other reflectors have been designed specifically to provide wide angle fighting distribution patterns, they are subject to different design considerations and usually result in decreased light intensity in certain regions in order to maximize the light intensity in other desired areas. While this provides an improved luminaire for specific lighting applications, such luminaires have limited utility for other lighting applications.
Thus, there is a substantial need for a reflector that can increase luminaire efficiency while providing increased wide angle lighting.
The luminaires may also be coated with suitable reflective coatings. However, there are several disadvantages lo such luminaires. First, the reflectors only redirect the light from the luminaire and are unable to increase the light output of the luminaire. Second, the coating materials are required in large quantities and are expensive to manufacture. Third, the molding and machining of the reflectors is cumbersome and expensive. Lastly. the reflectors do not increase the intensity of light emitted by the luminaire. Thus, in order to increase the illumination performance of a luminaire, the lamp within the luminaire must emit more light which increases the energy consumption.
Another approach used in some applications is to anodize the luminaire resulting in a highly reflective surface which reflects all the light emitted from the light source. The disadvantage of such a luminaire is thai the emitted light results in a high glare. The glare from such luminaires is hazardous thus limiting their use. E.g. the glare from these luminaires could be a driving hazard, and is also undesirable in applications such as outdoor lighting, lighting in petrol pumps, etc.
Further, none of the coating materials used in luminaires as disclosed in the prior art teach conversion of the UV radiation of the electromagnetic spectrum into visible light to increase the light output ratio of a luminaire.

Thus, there is a need for a luminaire having a coating system on the inner surface of the luminaire which increases the light output ratio by converting the UV radiation into visible light from the light emitted by the luminaire. Also, there is a need for a luminaire with a coating system which has an increased reflectivity resulting in reduced lieht absorption due to internal reflections within the luminaire and. which results in reduced glare in the light emitted by the luminaire. Thus, there is a need for a luminaire having a coating system on the inner surface which addresses these and other challenges.
OBJECTS OF THE INVENTION:
An object of the invention is to provide a luminaire comprising a reflector bodv having inner reflective surface, a light source and a means for electrically connecting the light source to the luminaire in which the inner reflective surface is designed to enhance liaht output thereof.
Another object of the invention is to provide a luminaire comprising a reflector body having inner reflective surface, a light source and a means for electrically connecting the light source to the luminaire in which the inner reflective surface is coated with highly efficient coating system to enhance light output thereof.
Another object of the invention is to provide a luminaire comprising a reflector body having inner reflective surface, a light source and a means for electrically connecting the light source to the luminaire in which the inner reflective surface is coated with highly efficient coating system, which are amenable to mass production.
Yet another object of the invention is to provide a highly efficient coating system for a luminaire to enhance the light output thereof.
Still another object of the invention is to provide a highly efficient coating system for a luminaire, which can be easily applied to reflector surfaces.
An additional object of the invention is to provide a highly efficient coating system for a luminaire. which are amenable to mass production.

Yet an additional object of the invention is to provide a method of the coating of inner reflective surface of the reflector body of the luminaire with the above-mentioned highly efficient coaling system to enhance the light output thereof.
Still an additional object of the invention is to provide a method of the coating of inner reflective surface of the reflector body of the luminaire with the above-mentioned highly efficient coating system, the method which is simple, economical and can be easily used for mass production.
Another additional object of the invention is to provide a luminaire comprising a reflector body having inner reflective surface, a light source and a means for electrically connecting the light source to the luminaire in which the inner reflective surface in combination with highly efficient coating system to increase the light output ratio of the luminaire up to 30%.
SUMMARY OF THE INVENTION:
According to this invention, there is provided a luminaire comprising a reflector body having an inner reflective surface and an outer protective cover, a light source and a means for electrically connecting said light source to said luminaire in which the light source is located inside a lighting fixture, characterized in that, the lighting fixture which encloses the light source is adapted to include increased curved reflective surfaces of the reflector by eliminating angular points off the surface in order to improve the irradiated light of the light source incumbent upon an inner reflective surface and further to improve the light radiated out of the enclosure / outer surface, and said inner reflective surface being applied with a coating in order to enhance the reflectivity of light, thus resulting in increased luminance.
Typically, the face of the reflective surface is perpendicular to the light source in a predefined manner in order to encourage increased spread of light emitted by the lighting source.
In accordance with an embodiment of this invention, shape of said luminaire is spherical, elliptical, square, trapezoidal or any other shape aesthetically pleasing with the desired light spread.

Typically, said coating comprises:
a. pigmented base coat; and
b. clear lop coat comprising a carrier resin and a nano-particulate luminescent
material, on top of said pigmented base coat.
Typically: said carrier resin is selected from a group of carrier resins consisting of alkyd. acrylic, polyurethane. epoxy, silicone, nitrocellulose., or combinations thereof.
Typically, said nano-particulate luminescent material is selected from a group of nano-particulate luminescent materials consisting of Zinc sulphide doped materials. Yttrium aluminum garnet doped materials, or combinations thereof.
Typically, said clear coat consisting of nano-particulate luminescent material is selected from a group consisting of Zinc sulphide doped materials, Yttrium aluminum garnet doped materials, or-combinations thereof in an amount of 0.01% to 25% by weight dispersed in a resin in an amount of 75% to 99.99% by weight with a wetting and dispersing agent in an amount of 0.1% to 2% by weight, a degassing agent in an amount of 0.1% to 2% by weight and a thinner in an amount of 5 phr to 90 phr.
Preferably, the concentration of the nano-particulate luminescent material ranges from 0.01% to 25%.
Typically, said clear coat composition comprises nano-particulate luminescent material in an amount of 2% by weight dispersed in a resin in an amount of 98% by weight with wetting and dispersing agent in an amount of 0.5% by weight, a degassing agent in an amount of 0.1 to 2%'by weight and a thinner in an amount of 80 phr.
Preferably, said pigment is selected from a group of pigments consisting of titanium dioxide, lithopone. zinc sulphide, barium sulphate, antimony oxide, talc, zinc oxide, alumina, calcium carbonate, calcium sulphate, silica, kaolin, or combinations thereof.
Typically, said pigmented base coat is white.
'Typically, said pigmented base coat is a liquid coat.

Alternatively, said pigmented base coat is a powder coat.
Preferably, said pigmented base coat is white, having whiteness in the range of 15 to 20.
Typically, said base coat contains alumina particles.
Preferably, said base coat contains alpha and gamma alumina.
Preferably, said coating is a matt finish coal.
Alternatively, said coatina is a semi-gloss finish coat.
Still alternatively, said coating is a gloss finish coat.
Typically, said coal has a thickness ranging from 40 microns to 80 microns.
Preferably, said coat has a thickness of 50 microns.
Typically, said coat further comprises a wetting and dispersing agent.
Typically, said coat further comprises a wetting and dispersing agent in an amount ranging from 0.1 % to 2% by weight.
Preferably, said coat further comprises a wetting and dispersing agent, said wetting and dispersing agent being Disper BYK 1 10.
Typically, said coat further comprises a degassing agent.
Typically, said coal further comprises a degassing agent in an amount ranging from 0.1% to 2% by weight.
Preferably, said coat further comprises a degassing agent, said degassing agent being BYK A 525.
Typically, said coat further comprises a thinner.

Typically, said coat further comprises a thinner in an amount ranging from 5 to 90 phr.
Preferably, said coat further comprises a thinner, said thinner being toluene.
Typically, said coat further comprises a wetting and dispersing agent selected from a group of agents based on silanes, condensates of ethylene or propylene oxide, acrylates, quaternary ammonium salts or esters of oils such as sorbitol mono-oleate.
Typically, said coat further comprises a degassing agent selected from agents based on silicones.
Typically, said coat further comprises a thinner selected from a group of thinners consisting of xylene, toluene, methyl ethyl ketone, acetone, butyl acetate, ethyl acetate, butyl cellosolve, ethyl cellosolve.
Typically, reflectance of the lurninaire is in the range of 65 to 80.
Typically, said coating has a thickness range from 20μ to 80μ.
Preferably, said coating has a thickness range from 20to 40μ.
Still preferably, said coating has a thickness not exceeding 80μ.
Typically, said clear coat is transparent.
Typically, said nano-particles are uniformly dispersed in the resin formulation of said clear coal.
According to this invention, there is provided a method for applying a coating to the inner reflective surface of the reflector body of the lurninaire as claimed in claim 1. said method comprising the steps of:
a. applying a pigmented base coat to the inner surface of a lurninaire;
b. curing the base coat followed by cooling the base coat;
c. applying a clear coat on the top of the said base coat: and

d. curing the top coat followed by cooling the top coat.
Typically, said base coat and said top coat are applied by an assisted air gun or any other conventional method.
Typically, said-base coat and said topcoat are applied at a pressure of 60-100 psi.
Preferably, said base coat and said top coat are cured thermally or air dried.
Typically, said base coat and said top coat are cured thermally at a range of 120° C to 140° C for 10 to 40 minutes.
Typically, viscosity of said base coat is 30-120 seconds on the B4 Ford cup.
Typically, viscosity of said top coat is 30 - 120 seconds on the B4 Ford cup.
Typically, thickness of said coating on the inner surface of the luminaire is 40 to 80microns.
Typically, said clear coat composition is prepared by dispersing nano-particulate luminescent material in an amount of 0.01 to 25% by weight in a resin in an amount of 75 to 99.99% by weight with a wetting and dispersing agent in an amount of 0.1 to 2% by weight, a degassing agent in an amount of 0.1 to 2% by weight and a thinner in an amount of 5 to 90 phr.
Typically, nano-particles are uniformly dispersed in the resin formulation of said clear coat.
Preferably, nano-particles are uniformly dispersed in the resin formulation of said clear coat by the process of sonication.
Alternatively, nano-particles are uniformly dispersed in the resin formulation ofsaid clear coat by the process of shear application.

Typically, nano-particles are uniformly dispersed in the resin formulation of said clear coat, said resin-nahoparlicle composition being sonicated for 4-10 hours at a frequency of 5 - 50 kHz at an intensity of 0.5 - 15 kW.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure la illustrates a side view of the position of light source in the lighting fixture in accordance with a.first embodiment of the lighting fixture;
Figure la illustrates an inner surface of the lighting fixture, where the developed coating is applied, in accordance with a first embodiment of the lighting fixture;
Figure 2a illustrates a side view of the position of light source in the lighting fixture in accordance with a second embodiment of the lighting fixture:
Figure 2a illustrates an inner surface of the lighting fixture, where the developed coating is applied, in accordance with a second embodiment of the lighting fixture;
Figure 3 illustrates Lighl-Outpul-Ration diagram of Fixture design of Figure 1 with conventional coating system;
Figure 4 illustrates Light-Output-Ration diagram of Fixture design of Figure 1 with claimed coating system:
Figure 5 illustrates Light-Output-Ration diagram of Fixture design of Figure 2 with conventional coating system; and
Figure 6 illustrates Light-Output-Ration diagram of Fixture design of Figure 2 with claimed coating system.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

Figure la illustrates a side view of the position of light souree (10) in the lighting fixture (100) in accordance with a first embodiment of the lighting fixture;
Figure la illustrates an inner surface of the lighting fixture (100), where the developed coating is applied, in accordance with a first embodiment of the lighting fixture;
Figure 2a illustrates a side view of the position of light source (20) in the lighting fixture (200) in accordance with a second embodiment of the lighting fixture: Figure 2a illustrates an inner surface of the lighting fixture (200), where the developed coating is applied, in accordance with a second embodiment of the lighting fixture;
According to this invention, there is provided a luminaire with improved light output and reflectivity. Typically, said luminaire is designed by considering certain pre-defined parameters of the luminaire like position of the light source in the luminaire, curvature of the reflective portion of the reflector body with or without angular positions, and the like structural parameters to enhance the light output. Typically, a coating is developed which is used as a coal on the luminaire for enhancing the light output.
In accordance with an embodiment of this invention, there is provided a luminaire comprising a reflector body having inner reflective surface and outer protective cover, a light source and a means for electrically connecting the light source to the luminaire in which the light source is located inside a lighting fixture in a manner such that the irradiated light of the light source incumbent upon an inner reflective surface is greatly improved. Further, the light source is located in such a manner that the light radiated out of the enclosure / outer surface is improved, too.
In accordance with yet another embodiment of this invention, the lighting fixture which encloses the light source is adapted to include increased curved reflective surfaces of the reflector as compared to the prior art. The design of such curved reflective surfaces oflhe reflector removes angular points o\T the surface. This reduction in angular points and enhancement in curvatures renders (he lighting fixture with increased light output with same input power.
In accordance with an additional embodiment of this invention, the face of the reflective surface which is perpendicular to the light source is designed in a manner to encourage increased spread of light emitted by the lighting source.

In accordance with yet another embodiment of this invention, the inner reflective surface is applied with an improved developed coating which enhances the reflectivity, thus resulting in increased luminance.
The luminaire designed with the respect to above-mentioned embodiments of the invention gives up to 1 5-20% improvement in the light output ratio.
In accordance with yet another embodiment of this invention there is provided highly efficient coating system for luminaires to increase the light output. The coaling system comprises:
c. a pigmented base coat; and
d. a clear top coat comprising a carrier resin and a nano-particulate luminescent
material, on the top of said pigmented base coat;
The said composition is applied on the inner reflective surface of the reflector body of the luminaire to increase the light output.
The carrier resin is selected from alkyd. acrylic, polyurelhane, epoxy, silicone, nitrocellulose, or combinations thereof The nano-particulate luminescent material is selected from a group comprising Zinc sulphide doped materials, Yttrium aluminum garnet doped materials, or combinations thereof. The concentration of the nano-particulate luminescent material is from 0.01-25%.
The pigment is selected from titanium dioxide, lilhopene, zinc sulphide, barium sulphate. antimony oxide, talc, zinc oxide, alumina, calcium carbonate, calcium sulphate, silica, kaolin, or combinations thereof. The pigmented base coat is white. The pigmented base coat is a liquid coat or a powder coat. The whiteness of the coating system is 1 5 to 20. The coating system is a matt, semi-gloss, or gloss type coating. The coating system has a thickness of 40 microns to 80 microns, preferably. 50 microns.
The coating system of the luminaires further comprises a wetting and dispersing agent in an amount of 0.1 to 2% by weight, a degassing agent in an amount of 0.1 to 2% by weight and a thinner in an amount of 5 to 90 phr. The wetting and dispersing agent is selected from but not limited to those based on s'ilancs. condensates of ethylene or propylene oxide, acrylates, quaternary ammonium salts or esters of oils such as sorbitol mono-oleate. The degassing agent is selected from but not limited to those based on silicones.

The thinner is selected from but not limited to xylene, toluene, methyl ethyl ketone, acetone, butyl acetate, ethyl acetate, butyl cellosolve, ethyl cellosolve, and the like. The reflectance of the coating system is 65 to 80.
The base coat is formulated to result in a white coaling and can be any commercially used coating system which satisfies this requirement. Thus, a liquid paint coat or a powder coat is applied as a base coat onto the reflector surface of the luminaire. The function of this base coat is to increase the reflection through the high refractive index of the pigments used in the coating system. The pigments and extenders used in these coating formulation could be chosen from titanium dioxide or its commercial replacements, lithopone, zinc sulphide, barium sulphate, antimony oxide, talc, zinc oxide, alumina, calcium carbonate, calcium sulphate, silica, kaolin and other clays among others pigments and extenders. The resin can also be chosen, but is not restricted to. from a list comprising alkyd. acrylics. polyurethanes, epoxies, silicones, nitrocellulose, among others. The coating may be a matt, semi-gloss or gloss type coating. In the present invention an epoxy-polyester hybrid powder coated system and an alkyd coating system is used.
The clear lop coat consists of a carrier resin with a high gloss containing nanoparticles of a luminescent material. The resin system may be chosen from a group consisting, but not limited to, alkyds. acrylics, polyurethanes, epoxies. silicones or nitrocellulose binders. The nano-particulate luminescent materials may be chosen from a groups comprising of ZnS based doped materials, Yttrium aluminum garnet doped nanoparticles and the like. In the present invention various ZnS doped nano-particles were used in the formulation of clear coat media. The use of nanoparticles over that of conventional microparticles is that the use of nano-particles in the composition will not affect the optical properties, i.e. the clarity of the film or the gloss of the film. Thus, the use of such materials in the formulation will lead to the transfer of the desired properties without affecting the existing optical properties of the coaling. The use of the nano-particles in the clear coat is advantageous since these particles will show optimal performance. If the particles were incorporated in the base pigmented coat then its efficiency would be restricted as only those particles present at the surface of the coating would interact with the incident radiation. However, in the case of incorporating the particles in the clear coat the interaction will occur with the incident radiation as well ijs with the radiation reflected from the white pigmented base coat. If the base coal wert; to contain alumina particles,

specifically alpha and gamma alumina, or similar particles, which would increase the reflectivity of the base coat would be advantageous.
The concentration of the nano-particlcs in the clear top coat has been optimized to 0.5% but could range up to 25%. It would be advantageous to use the nano-particles at a concentration level where it does not adversely affect the optical properties of the clear coat applied. The nano-particles would have to be uniformly dispersed in the resin formulation of the clear coat. This could be accomplished in a number of ways, including but not limited to sonication or shear application. The concentration of the nano-particles in the formulation could be that used in the final coating or an increased concentration which is then diluted before application. In the current method the nano-particles are dispersed via sonication for a time period sufficient to break any from agglomerates and uniformly disperse the particles. In general the resin-nanoparticle composition is sonicated for 4-10 hours at a frequency of 5 - 50 kHz and an intensity of 0.5 - 15 kW.
In accordance with yet another embodiment of this invention there is provided a method for applying a coating system to the inner reflective surface of the reflector body of the luminaire to increase the light output, said method comprising the steps of:
a. applying a pigmented base coal to the inner surface of a luminaire;
b. curing the base coat followed by cooling the base coat;
c. applying a clear coat on the top of the said base coat; and
d. curing the top coat followed by cooling the top coat.
The base coat and the top coat are applied by an assisted air gun or any other conventional method. The base coat and the top coat are applied at a pressure of 60-100 psi. The base coat and the top coat are cured thermally or air dried. The base coat and the top coat are cured thermally at 120 to 140° C for 10 to 40 mins. The viscosity of the base coat is 30 -120 seconds on the 134 Ford cup. The viscosity of the top coat is 30-120 seconds on the 134 Ford cup. The thickness of the coaling system on the inner surface of the luminaire is 40 to 80microns.
The method of application of the paint to the interior of the fixture was a standard application method. The fixture was suspended and the white paint applied to the fixture via an air assisted spray gun. The nozzle of the gun was kept at a distance of 1-2 feet from the surface to be coated and the coating was applied using a pressure of 60-100 psi. The

viscosity of the paint ranged between 50-500 mPas. In the case of short oil alkyd based while paints the paint was allowed to stabilize for 15 minutes in a dust free environment and then cured at I40°C for 15 minutes. The fixture was then cooled and then taken for the second coat to be applied. A similar procedure was followed. However, a clear coat using the nano-zinc sulphide particles was applied instead of the white paint. Following the paint application the fixture was allowed to stabilize and then cured at 140oC in the case of short oil stoving alkyd resins.
The light output of the luminaire is further increased by coatina the inner reflective surface of the reflector body of the luminaires with a highly efficient coaling system according to the invention.
According to the invention there is provided a luminaire comprising a reflector body having inner reflective surface and outer protective cover, a light source and a means for electrically connecting the light source to the luminaire in which the inner reflective surface is coated with the said highly efficient coating system to enhance the light output ratio.
The coating system comprises a pigment base coal on the inner reflective surface of the reflector body and a clear top coat comprising a carrier resin and a non-particuiate luminescent material on the top of the said base coat.
The inner reflective surface of the reflector body is substantially coated with the said
coaling system.
The Light output ratio of the luminaire is enhanced upto 1 5%.
If the luminaire is designed according to ihe invention and further the reflective surface of the reflector body is coated with highly efficient coating of the invention then this gives additional enhancement in the light output. The shape of the luminaire is spherical. elliptical, square, trapezoidal or any other shape aesthetically pleasing with the desired light spread.
The Light output ratio of the luminaire is 50 to 90% when the inner reflective surface of the re Hector body is coated with highly efficient coating system of the invention.

c clear coal consisting of nano-particulate luminescent material is selected from a group comprising Zinc sulphide doped materials, Yltrium aluminum garnet doped materials, or combinations thereof in an amount of 0.01 to 25% by weight dispersed in a resin in an amount of 75 to 99.99% by weight with a wetting and dispersing agent in an amount of 0.1 to 2% by weight, a degassing agent in an amount of 0.1 to 2% by weight and a thinner in an amount of 5 to 90 phr. Preferably, the clear coat composition comprises nano-particulate luminescent material is in an amount of 2% by weight dispersed in a resin in an amount of 98% by weight with welling and dispersing agent in an amount of 0.5% by weight, a degassing agent in an amount of 0.1 to 2% by weight and a thinner in an amount of 80 phr.
Preferably, the wetting and dispersing agent is DisperBYK. I 10. Preferably, the degassing agent is I3YK A 525. Preferably, the thinner is toluene,
The clear coat composition is prepared by dispersing nano-particulate luminescent material in an amount of 0.01 to 25% by weight in a resin in an amount of 75 to 99.99% by weight with a wetting and dispersing agent in an amount of 0.1 to 2% by weight, a degassing agent in an amount of 0.1 to 2% by weight and a thinner in an amount of 5 to 90 phr.
Preferably, the coating has a thickness of 20 to 80μ: ideally 20lo 40μ. On the other hand if the coating thickness is more than 80μ. the coating does not increase the performance
of the coating.
The manner in which the light source is located inside a lighting fixture, the curvature of reflective surfaces of the reflector body, reduction in angular points, keeping the face of the reflective surface perpendicular to the light source increases the light output with same input power. Zinc-sulphide nano-particles ordinarily coagulate when mixed with alkyd. epoxy. polyester or polyurethane or combinations thereof resulting in poor light output ratio of the composition. However, the clear coat of the coating system of the invention is the nano-composition, the interface between the resin and the nano-particles is stable, the nano-particles are uniformly dispersed in the resin and there is no coagulation. The clear coat is transparent. Light generated in the luminaire has visible light as well as non-visible light including UV light. When the non-visible light including UV light falls on the reflective surface of the reflector body some part of the light reflects

and some part of the light is absorbed by the clear coat. The light absorbed by the clear coat. UV light fraction of the light interacts with the luminescent nano-particulates and converts the same into visible light and reflects back. The base coat also helps to reflect the remaining light back. Thus overall reflection of light increases and hence, the light output ratio is also increased correspondingly. Also, the coating system comprising the pigmented base coal and the clear coat can be easily applied onto the reflective surfaces and binds well onto metallic reflective surfaces. The coaling system can be coated onto reflective surface of any colour to enhance their reflectivity. The optima] light output ratio is achieved when the coating system is coated onto reflectors having white pigmented base coat. A white pigmented base coat ordinarily absorbs a smaller fraction of the Jight falling on it as compared to other coloured surfaces. When lights falls on a white pigmented coat with the clear coat of the invention, the clear coat acts as a barrier preventing much of the absorption of light by the white pigmented coat and causes a larger percentage of the light falling on the surface to be reflected. Thus, the reflectivity of the white pigmented coat surface is enhanced by the clear coat of the invention. Also, the method of coaling is simple, economical and can easily be used for mass production of the luminaire coated with the coating system of the invention. The invention is thus advantageous in several aspects.
The design of the Fixture also plays an important role in the assessment of the performance of the coating with respect to the light output ratio (LOR). Thus it was decided thai the coating be applied to a number of fixture to ascertain its effect with respect to the LOR. From Figure la and corresponding Figures 3&4 it could be seen that the lighting fixture results in a more focused out put as compared to the lighting fixture described in Figure 2 with LOR diagrams shown in Figures 4&5. The design shown in figure 2 has been designed for a greater light spread, this is accomplished by the addition of contours on the. lateral surface of the reflector parallel to the length of the light source. This is accomplished by reflecting the light incident on the contours at various angles and is further increased by the shape of the reflector.
The invention will now be described in relation to an exemplary non-limiting example.
Figure 3 illustrates Light-Output-Ralion diagram of Fixture design of Figure 1 with conventional coating system;

Figure 4 illustrates Light-Output-Ration diagram of Fixture design of Figure 1 with claimed coating system;
Figure 5 illustrates Light-Output-Ration diagram of Fixture design of Figure 2 with conventional coating system; and
Figure 6 illustrates Lighl-Output-Ration diagram of Fixture design of Figure 2 with claimed coating system.
Example 1:
A white alkyd base coal was applied which had properties as shown in Table ] (below). The white base coat was applied and cured following the procedure described above. The coating was cured and the clear top coat applied following the procedure outlined above. After the application of the clear coat it was allowed to cure completely and then evaluated for its film thickness, whiteness, reflectance, gloss and LOR. The results of the film testing are shown in Table 1. The design of the fixture used in this case is as shown in Figure la. The LOR diagrams of the light fixtures with the conventional coating system is shown in Figure 3 and with the claimed coating is shown in Figure 4. The testing was carried out using a 1 1 W CFL lamp.
Figure la shows the position of the light source in the fixture. This will decide the LOR and performance of the lighting fixture. Figure lb shows the inner surface of the lighting fixture where the developed coating is applied. The testing was carried out using a 25W CFL lamp.
Example 2:
A white alkyd base coat was applied as per the procedure mentioned above, which had
properties as shown in Table I. The coating was cured and the clear top coat applied
following the procedure outlined above. After the application of the clear coat it was
allowed to cure .completely and then evaluated for its film thickness, whiteness,
reflectance, gloss and LOR. the results of which are given in 'Fable 1. The design of the
luminaire is as shown in Figure 2a. The LOR diagrams of the light fixtures with the
conventional coating system is shown in Figure 5 and with the claimed coating is shown
in Figure 6.
Figure 2 shows the position of the light source in the fixture. The lighting fixture is
different from that of the fixture showed in Figure la. The current fixture has more

curved surfaces with no angular points. The face perpendicular to the light source is so designed to allow for increased spread of the light.
Table 1: Evaluation of optical properties of coatings

Fixture Property
DFT (microns) Fixture Design 1 Fixture des gn2

Base coat Top coat Base coat Top coat

35-40 54-55 35-40
Whiteness 17-18 17-18 17-18 17-18
Reflectance 71-73 17-73 70-75 70-75
Gloss (20°) 70-75 68-72 7-10 30-40
Gloss (60°) 92-94 88-92 90-93 85-91
LOR 58.3 64.1 73.9 80.9
Maximum intensity 230 245 200 224
Intensity at 45° 175 200 170 180

We claim,
1. A luminaire comprising a reflector body having an inner reflective surface and an outer protective cover, a light source and a means for electrically connecting said light source to said-luminaire in which the light source is located inside a lighting fixture, characterized in that, the lighting fixture which encloses the light source is adapted to include increased curved reflective surfaces of the reflector by eliminating angular points off the surface in order to improve the irradiated light of the light source incumbent upon an inner reflective surface and further to improve the light radiated out of the enclosure / outer surface, and said inner reflective surface being applied with a coating in order to enhance the reflectivity of light, thus resulting in increased luminance.
2. A luminaire as claimed in claim 1 wherein, the face of the reflective surface is perpendicular to the light source in a pre-defined manner in order to encourage increased spread of light emitted by the lighting source.
3. A luminaire as claimed in claim I wherein, shape of said luminaire is spherical, elliptical, square, trapezoidal or any other shape aesthetically pleasing with the
desired light spread.
4. A luminaire as claimed in claim I wherein, said coating comprises:
a. pigmented base coat; and
b. clear top coal comprising a carrier resin and a nano-particulate luminescent
material, on top of said pigmented base coat.
5. A luminaire as claimed in claim 4 wherein, said carrier resin is selected from a group
of carrier resins consisting of alkyd, acrylic, polyurethane, epoxy. silicone,
nitrocellulose, or combinations thereof.

6. A luminaire as claimed in claim 4 wherein, said nano-particulate luminescent material is selected from a group of nano-particulate luminescent materials consisting of Zinc sulphide doped materials. Yttrium aluminum garnet doped materials, or combinations thereof.
7. A luminaire as claimed in claim 4 wherein, said clear coat consisting of nano-particulate luminescent material is selected from a group consisting of Zinc sulphide doped materials, Yttrium aluminum garnet doped materials, or combinations thereof in an amount of 0.01% to 25% by weight dispersed in a resin in an amount of 75% to 99.99% by weight with a wetting and dispersing agent in an amount of 0.1% to 2% by weight, a degassing agent in an amount of 0.1% to 2% by weight and a thinner in an amount of 5 phr to 90 phr.
8. A luminaire as claimed in claim 4 wherein, said clear coat composition comprises nano-particulate luminescent material in an amount of 2% by weight dispersed in a resin in an amount of 98% by weight with wetting and dispersing agent in an amount of 0.5% by weight, a degassing agent in an amount of 0.1 to 2% by weight and a thinner in an amount of 80 phr.
9. A luminaire as claimed in claim 4 wherein, said pigment is selected from a group of pigments consisting of titanium dioxide, lithopene, zinc sulphide, barium sulphate, antimony oxide, laic, zinc oxide, alumina, calcium carbonate, calcium sulphate, silica, kaolin, or combinations thereof.
10. A luminaire as claimed in claims 4 to 9 wherein, said wetting and dispersing agent is selected from a group of agents based on silanes. condensates of ethylene or propylene oxide, acrylates, quaternary ammonium salts or esters of oils such as sorbitol mono-oieate.

11. A luminaire as claimed in claims 4 to 9 wherein, said degassing agent is selected from agents based on silicones.
12. A luminaire as claimed in claims 4 to 9 wherein, said thinner selected from a group of thinners consisting oi' xylene, toluene, methyl ethyl ketone, acetone, butyl acetate, ethyl acetate, butyl cellosolvc. ethyl cellosolve.'
13. A luminaire as claimed in claims 1 to 12 wherein, the reflectance of the luminaire is in the range of 65 to 80.
14. A luminaire as claimed in claims I to 13 wherein, said coating has a thickness range from 20u to 80u.
15. A method for applying a coating to the inner reflective surface of the reflector body of the luminaire as claimed in claims 1 to 14;
said method comprising the steps of:
a. applying a pigmented base coat to the inner surface of a luminaire;
b. curing the base coat followed by cooling the base coat;
c. applying a clear coat on the top of the said base coat; and
d. curing the top coat followed by cooling the top coat.
16. A method as claimed in claim 15 wherein, said base coat and said top coat are applied at a pressure of 60-100 psi.
17. A method as claimed in claim 15 wherein, said base coat and said top coat are cured thermally or air dried.
18. A method as claimed in claim 15 wherein., said base coat and said top coat are cured thermally at a range of 120° C to 140° C for 10 to 40 minutes.

19. A method as claimed in claim I 5 to 18 wherein, thickness of said coating on the inner surface of the luminaire is 40 to 80microns.
20. A luminaire as claimed in claim 15 wherein, said clear coal composition is prepared by dispersing nano-particulate luminescent material in an amount of 0.01 to 25% bv weight in a resin in an amount of 75 to 99.99% by weight with a wetting and dispersing agent in an amount of 0.1 to 2% by weight, a degassing agent in an amount of 0.1 to 2% by weight and a thinner in an amount of 5 to 90 phr.
21. A method as claimed in claim 20 wherein, nano-particles are uniformly dispersed in the resin formulation of said clear coat by the process of sonicalion or shear application.