FIELD OF THE INVENTION
The present invention relates to a lighting luminaire and in particular to an energy efficient LED based intelligent lighting luminaire system such as those required for lighting targets such as billboards and the like. I^lore particularly, the Invention is directed to energy conserving and environment friendly Solid State Lighting (SSL) luminaire system deploying high brightness white LEDs adapted more specifically to illuminate uniformly targets such as huge billboards favouring saving about 50% of energy consumption involving conventional metal halide lamps with reflectors. Importantly, the LED based luminaire system employs specially designed optics for selective and efficient illumination of targets apart from economizing energy consumption. Advantageously, the SSL based luminaire system of the present invention is further adapted to favour longer operating life exceeding 15 years free of any maintenance/replacements, reduced green-house gas emissions, low voltage safe operation, low heat dissipation, with facilities for easy and selective control of Illumination intensity avoiding light pollution and easy adaptability for solar powered solution. The Solid State LED based luminaire system is further optionally adapted lOr Intelligent micro controller based light control and Intelligent on-off operation based on ambient light sensing or timing control based on real time clock or astronomical clock. The LED based luminaire system of the present invention is thus having wide prospects for Industrial production and application In a varied range of uses comprising both indoor and out door lighting such as for interior lighting/recessed down lights In film/ TV production, pathway lighting, high bay/Yard lighting, facade lighting for buildings and the flood lights and the like adapted for weather resistant mounting in a safe manner ensuring uniform illumination with minimal light trespass.
BACKGROUND ART
It is well known in the art of advertising and signage that the Vinyl Billboards of huge size such as 14 ft X 48 ft are usually used to convey commercial messages through text as well as images- static or dynamic-displayed by illumination. Such billboards are put up on rooftops and towers specially erected to hold them at suitable height to attract attention of trespassers, ensuring an impact on visibility either in daylight or at night. This is why billboard lighting assume importance. Luminalres of adequate power rating are used to illuminate the billboard uniformly creating the desired impact on viewers.

It is also experienced in the existing art of display of contents on billboards, usually metal halide lamps with reflectors are used having usual rating of 400w which distributes the light uniformly on the board. In the existing practice, usually four such luminaires are needed to illuminate a standard 14 ft x 48 ft billboard. Improvements in the luminaires systems by way of optics together with efficient integral ballast, the requirements were reduced to only two such luminaires of 400w to illuminate the billboard for sufficiency of viewing by target audience. However, the conventional billboard lighting systems suffer from a number of limitations apart from being high energy intensive, that needed to be appropriately addressed. The grid-based luminaires need significant power consumption and accompany related costs/tariff. Also the problem is aggravated during crisis/shortage of grid power. Thus low cost low power consuming illumination systems with equivalent or higher intensity of illumination appear essential. The prior art luminaires are primarily high intensity discharge lamps operating on high supply voltages wherein the light source produce light by establishing an electric arc through a gas mixture which need an Initial time to start due to the ballast. There has therefore been a need in the art to generate improved design configuration of such high Intensity metal halide based lamps to eliminate ballast and hence reducing the Initial time to start. It is also observed in the art that the existing ballast designs are prone to frequent breakdowns or burnouts necessitating maintenance and replacement of the lamp.
The luminaires of the prior art are essentially sources of significant amounts of greenhouse gas emissions due to dependency on the grid power, resulting In environmental pollution. Such luminaires are also essentially omnI directional giving away light in almost all 360" around. Use of such luminaires for directed lighting applications like the billboard lighting call for provisioning of reflectors to focus only on the desired size of the target billboard and avoid spillover beyond the edges. The conventional luminaires are moreover, manually operated for switching on/off resulting in considerable misuse of grid power.
There has been thus a continuing need in the art to develop Illuminating systems that would co.isume less power and also have reduced/no ballast requirement favoring faster response and also means for automatic on/off operation using intelligent and interactive systems facilitating operations automatically with associated power savings.

OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to provide a Solid State Lighting (SSL) solution or a green energy solution in the form of an LED based luminaire system adapted to energy efficient and environment friendly operation for various target lighting purposes including billboard lighting or the like application with longer operating life in a safe, reliable, energy efficient and cost effective manner providing uniform illumination at all points on the display panel, consuming approximately half the power consumption as compared to the conventional fluorescent, metal halide or other high-intensity discharge lamps presently used as lighting means.
A further object of the present invention directed to SSL based luminaire system for the billboard lighting and other indoor and outdoor applications wherein the use of solid state semiconductor based technology would provide for an effective alternative to the known use of metal halides and its emission related problems and would thus be further environment friendly.
A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications that can be adapted to be automatically activated using intelligent and interactive systems facilitating operations automatically with associated power savings.
A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting purpose adapted to use SSL based lighting systems such that the ballast requirements and flickers are eliminated providing advantageous fast response time and ensuring silent operation without burnout problems.
A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting which would ensure uniform illumination on the billboard and the like targets with less number of luminaires with equivalent intensity at 50% less power consumption.

A Still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting wherein the lighting could be achieved avoiding light pollution.
A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting wherein less number of luminaires consuming less power would be sufficient to illuminate a standard bill board with desired intensity uniformly on the board.
A still further object of the present Invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting wherein said LED based solid state lighting devices are adapted for operating life exceeding 15 years (more than 50,000 hrs) free of any maintenance or replacements.
A still further object of the present Invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting wherein constant light output is ensured over the entire life time of the luminaire favouring substantial energy saving.
A still further object of the present Invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting wherein said luminaires are mounted at bottom or top at normal plane to the vertical board favouring a minimum light trespass.
A still further object of the present Invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting wherein said luminaires are adapted for outdoor application in rugged and wet environmental conditions mounted in housing that is adapted for Ingress protection with IP66.
A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications Including that for billboard lighting wherein the design of optics ensures the light distribution pattern from the light source and the manner and pattern in which the light is distributed in order to maximize the light on board and/or favour the light utilization factor.

A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting wherein the I'ght distribution from the SSL based luminaires are adapted for selective distribution of the strength of illumination on the target object thereby providing a new and cost-effective illumination means for variety of Illumination purposes .
A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting involving an aesthetically designed housing for the mounting of the luminaires having thermal management taking into consideration the heat transfer from within the enclosure to outside, ensuring maintaining safe operating temperature to favour useful hours of life for the LEDs without degradation of intensity of the light emitted.
A still further object of the present invention directed to SSL based luminaire systems for the Indoor as well as outdoor applications including that for billboard lighting wherein said LED based solid state systems are adapted for microprocessor based intelligent control and an intelligent on/off operation based on ambient light sensing or timing control based on real time clock or astronomical clock for achieving further energy savings.
A still further object of the present invention directed to SSL based luminaire systems for the indoor as well as outdoor applications including that for billboard lighting involving microprocessor based Intelligent control for energy efficient uniform illumination of desired intensity which would be adapted to be networked and programmable.
A still further object of the present invention directed to SSL based luminaire systems for the Indoor as well as outdoor applications Including that for billboard lighting wherein said system is adapted to protect the lighting system from adverse weather conditions ensuring IP66 ingress protection.
SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided an energy efficient LED based intelligent lighting luminaire system comprising:

plurality of LEDs sourcing light of desired specifications and power depending upon the shape and size of the target to be illuminated housed within a housing; and optical lens system cooperatively disposed with respect to said LEDs sourcing unidirectional light to thereby produce for desired selective illumination on the target to be lit up.
Another aspect of the present invention is directed to an energy efficient LED based intelligent billboard lighting luminaire system comprising:
plurality of LEDs sourcing light of desired specifications and power depending upon the shape and size of the billboard to be uniformly lit housed within a housing; and optical lens system cooperatively disposed with respect to said LEDs sourcing unidirectional light to thereby produce for desired uniform illumination pattern on the target billboard.
A further aspect of the present Invention is directed to an energy efficient intelligent billboard lighting luminaire system wherein said optical system comprises lens means adapted to achieve said desired Illumination pattern.
A still further aspect of the present Invention is directed to an energy efficient intelligent lighting luminaire system wherein for billboard lighting said lens means is adapted such as to achieve desired uniform light distribution pattern from the LED light sources and improve the same In order to maximize the light on the board and reduce the light pollution and increase light utilization factor.
A still further aspect of the present invention is directed to meeting lES recommendations for billboard lighting applications for dark surroundings in respect of Lux levels and uniformity ratio - the ratio of lux levels at the centre (max) to periphery (min). The lES recommendations suggest the following lux levels for different surfaces to be illuminated;

Matte surfaces 1000 (bright) and 500 (dark surrounds) Glossy surfaces 500 (bright) and 200 (dark surrounds) and a uniformity ratio of 4:1 or better.
A stiil further aspect of the present Invention is directed to an energy efficient intelligent lighting luminaire system wherein for uniform billboard lighting the light distribution from the LEDs is modified by means of the lens system to be completely asymmetric in order to achieve the desired uniformity,
A still further aspect of the present invention is directed to an energy efficient intelligent lighting luminaire system wherein said arrangement of lenses comprises providing lens arrangement adapted to achieve the desired candela distribution such that the candela of the light from LED sources at low vertical angles which Is more, can be folded into higher vertical angle zones by total internal reflection thereby increasing the candela in higher vertical angle zones for achieving the desired uniformity In lighting of the target billboard placed perpendicular to the light sources.
According to an aspect of the invention the energy efficient LED based intelligent lighting luminaire system involves said optical lens system comprising a lens means adapted to provide for refraction and total Internal reflection to achieve desired Illumination on the hoarding.
A further aspect of the invention provides the energy efficient LED based intelligent lighting luminaire system wherein said optical lens comprises of a bottom surface and two free form surfaces one for refraction of the light rays and other for total internal reflection of light rays and includes inner space in the lens body and is asymmetrical around the center axis, said inner space having free-form shape such that light from the LED source is divided in to two parts, one part is refracted directly from the Inner surface and the other part undergoes total internal reflection at the side free-form surface and thus adapted to provide for the required illumination and concentration of light from refractive surface.
Yet another aspect of the Invention is directed to an energy efficient LED based intelligent lighting luminaire system wherein the said refractive free-form surface extends from top of the lens to the side which is facing the hoarding, said free-form refractive surface adapted

to provide refraction of light rays from the inner space and the light rays reflected by total internal reflection from the side face free-form surface, the said refractive surface having two free-from segments, one for refracting the light rays from the inner space and other for refracting light rays which are reflected by total internal reflection from the side surface.
A further aspect of the invention provides for an energy efficient LED based intelligent lighting luminaire system wherein said lens system basically comprises of two Integrally formed units (i) left unit and (ii) right unit facing the hoarding , the left unit comprising of one half of the inner space, side free-form surface for total internal reflection of light from the inner space and a refracting free-form surface segment to refract light from the side free-form surface, the right unit incorporating other half of the Inner space and another refracting free form surface segment.
In accordance with a preferred aspect of the invention in the said energy efficient LED based intelligent lighting luminaire system the said lens system is obtjined of polycarbonate / PMMA material.
A still further aspect of the present invention is directed to an energy efficient intelligent lighting luminaire system wherein said housing is, sturdy and aerodynamlcally designed for withstanding outside conditions and wind pressure and is provided with required ventilation for dissipating the heat generated.
According to yet another aspect of the present invention directed to an energy efficient intelligent lighting luminaire system comprising:
microcontroller based input light control and intelligent ON-OFF operation based on ambient light sensing and/or timing control.
A still further aspect of the present invention is directed to an energy efficient Intelligent lighting luminaire system comprising high brightness white LED.

A still further aspect of the present Invention is directed to an energy efficient intelligent lighting luminaire system comprising:
a power source operatlvely connected to an LED drive circuit;
said LED drive circuit electronics operatlvely connected to the said LED light source assembly;
said optical lens system cooperatively disposed with respect to the LED sources for said desired illumination of the target;
an auxiliary power source adapted to support light control electronics which is adapted to be activated based on signals received from the light source assembly for over-temperature protection, light sensor and /or any external interface units adapted for ON/OFF or dimming control of the luminaires.
A still further aspect of the present invention is directed to an energy efficient intelligent lighting luminaire system wherein said power source comprises AC mains power from the grid, means to convert the same to DC to power said LED drive; and means for constantly monitoring for high and low level violations to cut-off AC power In such situations to safeguard the luminaires.
The present invention and its objects and advantages are described in greater details with reference to the following accompanying non limiting illustrative figures.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1: is the schematic illustration of the SS Billboard lighting Luminaire system according to the present Invention showing the different units in the system and their relations by means of a blocl< diagram.
Figure 2: is the schematic diagram of the billboard lighting using SSL system of the invention showing the distribution scheme of light beams at various locations on the standard 14 ft x 24 ft area of board for desired uniform illumination.

Figure 3: is the schematic illustration of the performance of the improved optics configuration for the SSL luminaires for desired uniform intensity of illumination wherein more intensified light beam emerges from the luminaires at higher vertical angles and vice versa, as schematically shown In the estimated relative candela polar diagram.
Figure 4a: is the schematic Illustration of the candela polar diagram for SSL system without lens.
Figure 4b: Is the polar diagram with lens for favoured polar candela distribution required for the uniform high Intensity light emitting from the luminaires and incident on board.
Figure 4c: Is the schematic illustration of the Iso-candela plot of the luminescence over the billboard lit with SSL system according to the present Invention to evaluate the bill board lighting uniformity using photometrics.
Figure 5: is the schematic illustration of the housing of the SSL luminaires showing the nature of light distribution direction without requiring tilting of the luminaire/LED PCB.
Figure 6: is the image of the LED based luminaire for use in the SSL system for billboard lighting according to the present invention showing in its three views.
Figure 7: is the schematic illustration of the disposition of the single unit SSL luminaire system according to an embodiment of the invention for lighting of the standard 14ft x 24 ft billboard and the preferred disposition and spacing of said single SSL luminaire with respect to the bill board at right angles to each other.
Figure 8: is the schematic illustration of the lens configuration of the SSL luminaire system of the invention, showing its different portions having free forms on top and side face enabling directing high intensity light beams for desired uniform intensity of illumination on the bill board, either by direct refraction through one part and internal total reflection through another part of the lens.
Figure 9: is the schematic illustration of side view of distribution pattern of the refracted light beam emerging from the SSL based luminaires through the selective lens configuration wherein some light beams are directed by simple refraction through one part

of the lens of each Chip-LED module and some low angle light beams are subjected to total internal reflection to direct the beams to higher vertical angles for desired uniform illumination of the billboard.
Figure 10 a & b: is the schematic lllustration of the front view(a) and the top view(b) of the lens assembly of the SSL based billboard lighting iuminaires device according to the present invention directed to illuminate the bill board uniformly.
Figure 11: is the image of the SSL luminaire unit according to the Invention comprising plurality of LEDs selectively disposed in an array.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES
The Invention discussed hereinbefore thus relates to Solid State LED based Iuminaires for target lighting such as bill board lighting and other applications adapted for intelligent automatically controlled illumination of uniform intensity across the board. Importantly, the luminaire system of the invention also involves advantageous use of electronic control of on/off operation as well as ambient light sensitive control of illumination that can further be enhanced for reliable performance and energy efficiency by incorporation of microprocessor based lighting control and adaptability to be networked as well as programmable. The LED based luminaire system apart from being cost-effective by way of selective involvement of optics with LED light sources advantageously enable control on light beam direction and distribution for variety of possible modulations of illumination of targets including the required uniform illumination of desired intensity with longer operating life of such SSL luminaire systems for billboards and the like free of any maintenance or replacement.
Reference is first invited to the accompanying Figure 1 that schematically illustrates SSL lighting system according to the present invention showing the different units in the system and their functional relationship by means of a block diagram. The functional realization of the luminaire is achieved through various elements as shown schematically in the bioci< diagram of Figure 1. The luminaire receives AC power from the grid (11), which is converted to DC (12) such as by a solid state rectifier unit to power constant

current driving of the LED drive electronics (15) and the LED light source assembly (16). Optics (17) deals with the arrangement of lenses to achieve desired illumination pattern on the target billboard. The mains input is constantly monitored for high and low level violations to CLt-off AC power (13) under such situations to safeguard the luminaire. Auxiliary power (14) is derived to support the light control electronics (18) which gets activated on receiving appropriate signals from the light source assembly (16) for over-temperature protection, light sensor (20) and/or any external interface units (21) like RF etc. for On/Off operation or dimming control of the luminaire.
According to an advantageous aspect of the Invention the illumination per unit of energy input is further improved and the Intensity of illumination is uniformly maintained all over the billboard by adopting an improved optics configuration for the SSL device with housing. Reference Is now invited to the accompanying Figure 2, showing schematically the distribution scheme of light beams at various locations on the standard 14 ft x 24 ft area of board for desired uniform Illumination using the energy efficient SSL luminaire system of the present Invention. The purpose of the optics Is to modify the light output of the LEDs to achieve desired levels of illumination pattern on the target surface. The design configuration of optics essentially deals with the distribution of the light beams/pattern from the light source and the manner in which this pattern can be improved In order to maximize the light on the board, reduce the light pollution such as the light trespass or sky glow and consequently increase the light utilization factor. The optics design thus ensures an acceptable level of uniformity of illumination on the board rearranging for the light to be more on to the top/bottom edges as well as to the sides of the entire stretch of the billboard. Since the optics is intended to project the light beams evenly on the board at a height of about 4 -5 tinies the mounting distance. It may be noticed that the distance light travels is minimum for area '1' and is higher for the higher numbered areas as shown in the accompanying Figure 2, It Is thus required that the luminaire is configured to project high intensity light (higher candela) beam towards the higher numbered areas e.g. 4,5,6 etc. as compared to the intensity of light beam projected to areas 1,2,3 etc. as illustrated in the accompanying Figure 2. The need for modification of light distribution from the LED based luminaire is thus accomplished by appropriate optics design involving lenses of physical characteristic parameters which is completely asymmetric as laid over the LED/ luminaire housing in order to achieve desired uniformity of illumination of equal intensity ail over the board.

It is also an important aspect of the present invention that to achieve uniformity of the illumination on the board, the requirement is that the more intensified light beam must emerge from luminaire at higher vertical angles i.e. candela of the lamp should be more and vice versa. Accordingly, relative candela polar diagram can be estimated as shown in the accompanying Figure 3.
In order to achieve desired candela distribution, appropriate lens design for the SSL luminaire system Is essential. Since the candela of the LED lamp at low vertical angles Is more, light beams are folded into high vertical angle zone by adopting total Internal reflection by suitable lens design and thereby increasing the candela there relatively. Lens design also enable no tilt angle of the luminaire. The luminaire is mounted horizontally such that its plane Is perpendicular to the board.
The mechanical design of the metallic housing for the SSL luminaire system Is made of aluminium alloy die casting with aesthetically good appearance that also takes Into consideration the heat transfer from within the enclosure to the outside. Insufficient ventilation can raise the ambient temperature within the enclosure and adversely affect the LED characteristics and useful hours of life beyond which degradation in the intensity of the light emitted is expected to occur. The housing Is sturdy and aerodynamlcally designed to withstand wind pressure and also ingress protected with IP66.
Attention is now Invited to the accompanying Figure 4a wherein the candela polar diagram has been illustrated showing the uniform distribution of light beam all around 360° of equal intensity without any provision of lens In the luminaire/LED lamps; The accompanying Figure 4b on the otherhand shows the candela polar diagram for the light beam distribution when appropriate lens design is provided in the SSL luminaire as of the present invention such that the more of the low angle light beams from LEDs are folded into high vertical angle zone using the principle of total internal reflection of optics adopted through appropriately configured lens and their desired disposition on the lumlnalres/housing.
Accompanying Figure 4c is the schematic illustration of the iso-candeia plot of the illumination at various locations on the billboard lit with SSL luminaire using photometrics. The degrees in the said iso-candeia plot represent the angular positions of the billboard to designate the respective area selected for carrying out measurement of illumination. It is

also apparent from each of the said iso-candela plots having the indication of % of maximum illumination (8549 Cd) and also the magnitude available/obtained along each such plot.
Reference Is now invited to the accompanying Figure 5 that schematically illustrates the housing/mounting of the SSL luminaires disposed horizontally at top or bottom of the billboard showing the direction of light distribution without requiring tilting of the luminaire/LED PCB by selective provisioning of the optics design comprising required lens configuration and preferred disposition on LED/ lumlnalre housing.
Reference is now invited to the accompanying Figure 6 that shows the Image of an LED based lumlnalre used for the SSL system for billboard lighting. The dimensions of such lumlnalre are illustrated In the top view, front view and the side view in said Image and the all major dimensions of said lumlnalre alongwith the selective housing configuration for desired outdoor weather resistant application.
Reference is now invited to the accompanying Figure 7 that schematically illustrates an embodiment of the SSL based lumlnalre system for billboard lighting showing the preferred disposition of single SSL lumlnalre unit with respect to a standard 14 ft x 24 ft billboard, the planes being at right angles to each other and the different spacing and distances in said selective disposition. The spacing and the selective disposition ensuring desired distribution of light beam in combination with the selective optics comprising lens favoring Inward directed light beam at selectively targeted heights, for desired uniform light intensity over the various areas of the billboard.
Reference is now invited to the accompanying Figure 8 that schematically illustrates the lens configuration showing its free form refraction surfaces at selective locations to achieve desired uniform illumination on billboard or the like. It is clearly apparent from the accompanying Figure 8, that the lens here in described provides refraction and total internal reflection in order to achieve desired illumination on the hoarding. The lens for the LED source according to the present embodiment of the Invention is made up of polycarbonate or PMMA and includes lens body. The lens has a bottom surface and two free -form surfaces one for refraction of the light rays and other for total internal reflection of light rays. The lens further includes inner space In the lens body and is asymmetrical around the center axis. The inner space has free-form shape such that light from the LED

source is divided Into two parts, one part is refracted directiy from the inner surface and the other part undergoes totai internal reflection at the side free-form surface and thus provides required Illumination and concentration of light from refractive surface. The accompanying Figure 8 shows that the lens is configured to have refractive free-form surface extending from top of the lens to the side which is facing the hoarding. This free-form refractive surface provides refraction of light rays from the Inner space and the light rays reflected by total Internal reflection from the side face free-form surface. The refractive surface is thus having two free-from segments, one for refracting the light rays from the inner space and other for refracting light rays which are reflected by total Internal reflection from the side surface.
Preferably the lens described In the present Invention as shown in Figure 8 can be divided to in a left unit (a) and a right unit (b), and said right unit is facing the billboard/hoarding. The left unit (a) consists of one half of the inner space (c), side face free-form surface (SFS) for total internal reflection of light from the inner space (c) and a refracting free-form surface segment to refract light from the side free-form surface. The right unit (b) Incorporates other half of the inner space and another refracting free form surface (RFS) segment for refraction of light beam emitted from the LED source.
Reference is now Invited to the accompanying Figure 9 that schematically Illustrates the distribution pattern of the refracted light beam in a side view, emerging from the SSL based luminaries through the selective lens configuration wherein some light beams are directed by simple refraction through one part of the lens e.g. part (b) of lens of each Chip-LED module, while some low angle light beams are subjected to total internal reflection to direct the beams to higher vertical angles through the side free form surface of lens e.g. part (a) of lens, for desired uniform illumination of the billboard, even when the luminalre device is installed at the bottom of vertical billboard with Its surface orthogonal to the plane of the SSL luminalre as shown In the arrangement of Figure 7.
Reference is now invited to the accompanying Figure 10 a & b show the front view and the top view of the lens assembly on the SSL based billboard lighting device of the present invention directed to uniform distribution of the refracted light beams emerging from the SSL lumlnalres wherein the portion of / free form surface of lens engaged in simple reflection of light beams from a SSL source, the portion engaged in total internal reflection

of light beams and the internal space in the lens for housing a Chip based LED in the SSL unit have been illustrated.
Reference is now invited to the accompanying Figure 11 which shows an embodiment of the billboard lighting SSL lumlnaire assembly unit according to the present invention comprising an illustrative array of 120(15x8) chip LEDs in combination with the optical lens arrangement in said assembly.
According to an exemplary illustration of a standard configuration of the SSL luminaire of the present Invention, the technical specification of the SSL lighting systems for billboard lighting or like purposes Is summarized in the following accompanying Table I.
TABLE I;
Broad Technical Features of the Energy Efficient SSL luminaires For Billboard Lighting:



It is thus possible by way of tlie present invention to develop a system for Solid State Lighting (SSL) LED based-luminaire system for variety of target Illumination such as billboard lighting and like applications that would be capable of saving energy upto 50% of the energy consumed by conventional metal halide or mercury based lighting devices. Importantly, the SSL lighting system is further adapted for automatic on/off switching operation through electronic control based on ambient lighting and thus saving on energy and also Impose timing control and is having aesthetically designed weather resistant housing for its mounting In outdoor applications. Advantageously also, the SSL lighting system of the present Invention having selective application of optics involving lenses and selective disposition thereof such that the lens design is completely asymmetric in order to achieve the desired uniformity in intensity of lighting of billboards with increased light utilization factor. The SSL lighting systems for billboard lighting Is thus energy efficient, low cost, low voltage, fast response, safe and reliable, environment friendly device/system with controlled heat dissipation for desired longer operating life of such lighting systems exceeding 50,000 hrs or 15 years of service with constant light output over life time, free of any burnout/flicker related problems. Such Solid State semiconductor based LED lighting systems for interior as well as out door application is adapted for microprocessor based illumination control, ambient light sensitive on/off operation and ability to be networked and programmable. The SSL based lighting systems are thus having prospects of wide industrial application for a number of end uses comprising area/park lighting, pathway/highbay/yard lighting, Billboard or boundary lighting. Facade lighting, interior /recessed down lighting application for Film / TV studios, for household occasions and industrial purposes. These can also be used in vehicles fitted with Generators for mobile application like focus lights in procession etc.

1. An energy efficient LED based intelligent lighting luminaire system comprising:
plurality of LEDs sourcing light of desired specifications and power depending upon the shape and size of the target to be illuminated housed within a housing; and optical lens system cooperatively disposed with respect to said LEDs sourcing the light to thereby produce for selective desired illumination on the target to be lit up.
2. An energy efficient LED based Intelligent billboard lighting Iuminaire system
comprising:
plurality of LEDs sourcing light of desired specifications and power depending upon the shape and size of the billboard to be uniformly lit housed within a housing; and optical lens system cooperatively disposed with respect to said LEDs sourcing the lighi to thereby produce for desired uniform illumination of the target billboard.
3. An energy efficient intelligent billboard lighting Iuminaire system as claimed in an/one of claims 1 to 2 wherein said optical system comprises lens means adapted to achieve said desired illumination of the target.
4. An energy efficient Intelligent lighting Iuminaire system as claimed in anyone of claims 2 to 3 wherein for billboard lighting said lens means Is adapted such as to achieve desired uniform light distribution pattern from the LED light sources and improve the same in order to maximize the light on the board and reduce the light pollution and increase light utilization factor.
5. An energy efficient intelligent lighting Iuminaire system as claimed in anyone of claims 2 to 4 wherein for uniform billboard lighting the light distribution from the LEDs are modified by means of the lens system to be completely asymmetric in order to achieve the desired uniformity.
6. An energy efficient intelligent lighting Iuminaire system as claimed in anyone of claims 2 to 5 wherein said arrangement of lenses comprises providing lens

arrangement adapted to achieve candela distribution such that the candela of the light from LED sources at low vertical angles which is more can be folded into higher vertical angle zones by total internal reflection thereby increasing the candela in higher vertical angle zones for achieving the desired uniformity in lighting of the target billboard placed perpendicular to the light sources.
7. An energy efficient LED based Intelligent lighting luminaire system as claimed in anyone of claims 1 to 6 wherein said optical lens system comprises a lens means adapted to provide for refraction and total internal reflection to achieve desired illumination on the hoarding.
8. An energy efficient LED based intelligent lighting luminaire system as claimed in anyone of claims 1 to 7 wherein said optical lens comprises of a bottom surface and two free-form surfaces one for refraction of the light rays and other for total internal reflection of light rays and includes inner space in the lens body and Is asymmetrical around the center axis, said inner space having free-form shape such that light from the LED source is divided into two parts, one part is refracted directly from the Inner surface and the other part undergoes total Internal reflection at the side free-form surface and thus adapted to provide for the required Illumination and concentration of light from refractive surface.
9. An energy efficient LED based intelligent lighting luminaire system as claimed In anyone of claims 1 to 8 wherein the said refractive free-form surface extends from top of the lens to the side which is facing the hoarding, the said free-form refractive surface adapted to provide refraction of light rays from the inner space and the light rays reflected by total internal reflection from the side face free-form surface, the said refractive surface having two free-from segments, one for refracting the light rays from the inner space and other for refracting light rays which are reflected by total internal reflection from the side surface.
10. An energy efficient LED based intelligent lighting luminaire system as claimed in anyone of claims 1 to 9 wherein the said lens system basically comprises of two integrally formed units (1) left unit and (ii) right unit facing the hoarding , the left unit comprising of one half of the inner space, side free-form surface for total internal reflection of light from the inner space and a refracting free-form surface

segment to refract light from the side free-form surface, the right unit incorporating other half of the inner space and another refracting free form surface segment.
11. An energy efficient LED based intelligent lighting luminaire system as claimed in anyone of claims 1 to 10 wherein said lens system is obtained of polycarbonate / PIMIMA material.
12. An energy efficient intelligent lighting luminaire system as claimed In anyone of claims 1 to 11 wherein said housing Is sturdy and aerodynamically designed for withstanding outside conditions and wind pressures and is provided with required ventilation.
13. An energy efficient iitelllgent lighting luminaire system as claimed In anyone of claims 1 to 12 comprising:
microcontroller based Input light control and intelligent ON-OFF operation based on ambient light sensing and/or timing control.
14. An energy efficient intelligent lighting luminaire system as claimed in anyone of claims 1 to 13 wherein the LED source comprising high brightness white LED.
15. An energy efficient intelligent lighting luminaire system as claimed in anyone of claims 1 to 14 comprising:
a power source operatively connected to an LED drive circuit;
said LED drive circuit electronics operatively connected to the said LED light source
assembly;
said optical lens system cooperatively disposed with respect to the LED sources for
said desired illumination of the target;
an auxiliary power source adapted to support light control electronics which is
adapted to be activated based on signals received from the light source assembly
for over-temperature protection, light sensor and /or any external interface units
adapted for ON/OFF or dimming control of the iuminaires.
16. An energy efficient intelligent lighting luminaire system as claimed in claim 15
wherein said power source comprises AC mains power from the grid, means to

convert the same to DC to power said LED drive; and means for constantly monitoring for high and low level violations of the AC input to cut-off the AC power In such situations to safeguard the lumlnaire.
17. An energy efficient Intelligent lighting lumlnaire system substantially as hereindescribed and illustrated with reference to the accompanying figures.