INCLUDING RF SHIELDING

Cross Reference to Related Application

[0001] This application is related to US Application Serial No. 61/784,613, filed on March 14, 2013 and US Application Serial No. 13/829,131, filed on March 14, 2013, the entire disclosures of which are expressly incorporated herein by reference.

Background and Summary of the Disclosure

[0002] The present disclosure relates to a lighting apparatus. More particularly, the present disclosure relates to an energy efficient light emitting plasma lighting apparatus having a compact design, effective heat management characteristics, and a reduced level of radio frequency (RF) emissions.

[0003] Light emitting plasma (LEP) lights which produce energy efficient, high intensity output light are well known. Typically, a LEP lighting apparatus emits a full-spectrum white light which can be rapidly dimmed to about twenty percent (20%) of its light output.

[0004] An illustrated LEP lighting apparatus includes an emitter having a quartz lamp embedded in a ceramic resonator or puck. A RF generator and microcontroller provide a RF driver which is connected to the emitter. The RF signal generated by the driver is coupled to the puck by a coaxial cable. The puck concentrates the RF field delivering energy to the sealed quartz lamp without the use of electrodes or filaments. The highly concentrated RF field ionizes the gases and vaporizes halides within the quartz lamp, thereby creating a plasma state at its center, resulting in an intense source of white light.

[0005] A LEP lighting apparatus emits an RF field in addition to the white light.

Conventional LEP lights use a grounded conductive material such as a mesh, screen, film or coating covering a window of a reflector housing containing the plasma bulb to reduce the RF field emitted by the light. However, such conductive material covering the entire window of the reflector housing reduces the intensity of light emitted by the LEP lighting apparatus by about 15-20%. [0006] The LEP lighting apparatus of the present disclosure does not use a conductive material covering the entire window in order to reduce the emitted RF field to an acceptable level. In certain illustrated embodiments of the present disclosure, the conductive material on the window is eliminated. In other embodiments, a conductive material such as a screen, mesh, coating or film covers less than the entire window to increase the amount of light emitted from lighting apparatus. In a further embodiment, the entire window is fully covered with a conductive material. However, the conductive material has a higher light transmission factor than conductive material used in conventional plasma lights without the RF shielding baffles of the present disclosure. Therefore, the embodiments of the present disclose achieve similar RF shielding with a higher light output than is achieved through the use of the lower light transmission RF shielding mesh alone.

[0007] In one illustrated embodiment of the present disclosure, a light emitting plasma lighting apparatus is driven by a driver which generates a radio frequency (RF) output signal. The light emitting plasma lighting apparatus includes a reflector housing having first and second openings, and an emitter including a body portion coupled to the first opening of the reflector housing. The body portion of the emitter has an opening therein. The emitter also includes a puck located in the opening of the body portion. The puck has an exposed bottom surface and a plasma bulb coupled to the bottom surface of the puck. The puck is coupled to the driver to receive the RF output signal and provide a concentrated RF field so that light is emitted from an outer surface of the plasma bulb and an RF field is emitted from the bottom surface of the puck. The light emitting plasma lighting apparatus also includes a reflector located in the reflector housing to direct light emitted from the plasma bulb through the second opening, a window positioned over the second opening of the reflector housing spaced apart from the plasma bulb so that light emitted from the plasma bulb passes through the window, and at least one conductive RF shielding baffle located in the reflector housing between the emitter and the window. The at least one RF shielding baffle includes a planar body portion aligned generally perpendicular to the outer surface of the plasma bulb to minimize interference with light emitted from the plasma bulb. The at least on RF shielding baffle is grounded to absorb a portion of the RF field emitted by puck. [0008] In one illustrated embodiment, a plurality of RF shielding baffles are coupled to the body portion of the emitter. The planar body portion of each of the plurality of RF shielding baffles being aligned generally perpendicular to the outer surface of the plasma bulb.

[0009] In another illustrated embodiment, the at least one conductive RF shielding baffle is coupled to the reflector. For example, first and second RF shielding baffles are coupled to the reflector with planar body portions of the first and second RF shielding baffles aligned perpendicular to the bottom surface of the puck. Illustratively, the first and second RF shielding baffles intersect at a point aligned with the plasma bulb.

[0010] In yet another illustrated embodiment, a plurality of inner baffles are coupled to the first and second RF shielding baffles. The plurality of inner baffles each include a planar body portion aligned generally perpendicular to the outer surface of the plasma bulb.

[0011] In a further illustrated embodiment of the present disclosure, a light emitting plasma emitter apparatus includes a metal body portion defining an opening therein, and a puck located in the opening of the body portion. The puck has an exposed bottom surface and a plasma bulb coupled to the bottom surface of the puck. The puck is configured to provide a concentrated RF field from a RF signal received from a driver so that light is emitted from an outer surface of the plasma bulb and an RF field is emitted from the bottom surface of the puck. The light emitting plasma emitter apparatus also includes and at least one conductive RF shielding baffle coupled to the body portion over the bottom surface of the puck. The RF shielding baffle includes a planar body portion aligned generally perpendicular to the outer surface of the plasma bulb. The RF shielding baffle is grounded to absorb a portion of the RF field emitted from the bottom surface of the puck.

[0012] In another illustrated embodiment of the present disclosure, a light emitting plasma lighting apparatus is driven by a driver which generates a radio frequency (RF) output signal. The light emitting plasma lighting apparatus includes a reflector housing having first and second openings, and an emitter coupled to the first opening of the reflector housing. The emitter includes a puck having a bottom surface and a plasma bulb coupled to the bottom surface of the puck. The puck is coupled to the driver to receive the RF output signal so that light emitted from an outer surface of the plasma bulb and an RF field is emitted from the puck. The light emitting plasma lighting apparatus also includes a reflector located in the reflector housing to direct light emitted by the plasma bulb through the second opening, a window positioned over the second opening of the reflector housing spaced apart from the plasma bulb so that light emitted by the plasma bulb passes through the window, and at least one conductive portion covering at least one selected portion of the window. The at least one selected portion has a combined area less than an overall area of the window. The at least one conductive portion is grounded to absorb portions of the RF field emitted by the puck.

[0013] The LEP lighting apparatus of the present disclosure does not use a conductive material covering the entire window in order to reduce the emitted RF field to an acceptable level. In certain illustrated embodiments of the present disclosure, the conductive material on the window is eliminated. In other embodiments, a conductive material such as a screen, mesh, coating or film covers less than the entire window to increase the amount of light emitted from lighting apparatus. In a further embodiment, the entire window is fully covered with a conductive material. However, the conductive material has a higher light transmission factor than conductive material used in conventional plasma lights without the RF shielding baffles of the present disclosure. Therefore, the embodiments of the present disclose achieve similar RF shielding with a higher light output than is achieved through the use of the lower light transmission RF shielding mesh alone.

[0014] In an illustrated embodiment of the present disclosure, a light emitting plasma lighting apparatus is driven by a radio frequency (RF) output signal from a driver. The lighting apparatus includes a reflector housing having first and second openings, and an emitter coupled to the first opening of the reflector housing. The emitter includes a puck having a bottom surface and a plasma bulb coupled to the bottom surface of the puck. The puck is coupled to the driver to receive the RF output signal so that light is emitted from the plasma bulb and an RF field is emitted from the puck. The lighting apparatus also includes a reflector located in the reflector housing to direct light emitted by the plasma bulb through the second opening, a window positioned over the second opening of the reflector housing spaced apart from the plasma bulb so that light emitted by the plasma bulb passes through the window, and a RF shielding plate coupled to the emitter and positioned over the bottom surface of the puck. The RF shielding plate is formed to include an aperture to expose the plasma bulb. The aperture is sized to provide a gap between the RF shielding plate and the plasma bulb surrounding the plasma bulb, and the RF shielding plate is grounded to absorb a portion of the RF field emitted by puck.

[0015] In another illustrated embodiment of the present disclosure, a light emitting plasma lighting apparatus is driven by a radio frequency (RF) output signal from a driver. The lighting apparatus includes a reflector housing having first and second openings, and an emitter coupled to the first opening of the reflector housing. The emitter includes a puck having a bottom surface and a plasma bulb coupled to the bottom surface of the puck. The puck is coupled to the driver to receive the RF output signal so that light emitted from the plasma bulb and an RF field is emitted from the puck. The lighting apparatus also includes a reflector located in the reflector housing, the reflector including a light receiving portion configured to direct light from the plasma bulb through the second opening, a window positioned over the second opening of the reflector housing spaced apart from the plasma bulb so that light produced by the plasma bulb passes through the window, and means located between the bottom surface of the puck and the light receiving portion of the reflector for reducing the RF field emitted by puck before the RF field reaches the light receiving portion of the reflector.

[0016] In yet another illustrated embodiment of the present disclosure, a light emitting plasma emitter includes a metal body portion defining an opening therein, and a puck located in the opening of the body portion. The puck has an exposed bottom surface and a plasma bulb coupled to the bottom surface of the puck. The puck is configured to provide a concentrated RF field from a RF signal received from a driver so that light is emitted from the plasma bulb and an RF field is emitted from the puck. The light emitting plasma emitter also includes a conductive RF shielding plate coupled to the body portion and positioned over the bottom surface of the puck. The RF shielding plate is formed to include an aperture to expose the plasma bulb. The aperture is sized to provide a gap between the RF shielding plate and the plasma bulb

surrounding the plasma bulb. The RF shielding plate is grounded to absorb a portion of the RF field emitted by puck. [0017] Additional features and advantages of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the invention as presently perceived.

Brief Description of the Drawings

[0018] Features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of certain embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0019] FIG. 1 is a block diagram illustrating an exemplary light emitting plasma (LEP) lighting apparatus of the present disclosure;

[0020] FIG. 2 is a bottom, perspective view illustrating one embodiment of an exemplary lighting apparatus of the present disclosure;

[0021] FIG. 3 is a perspective view illustrating an emitter of FIG. 2 and a plurality of radio frequency (RF) shielding baffles coupled to the emitter;

[0022] FIG. 4 is a plan view of a bottom surface of the emitter of FIG. 3 illustrating further details of the plurality of baffles situated around a bulb of the emitter;

[0023] FIG. 5 is a side view of the emitter of FIGS. 3 and 4;

[0024] FIG. 6 is a side view of the emitter of FIG. 5;

[0025] FIG. 7 illustrates details of one of the plurality of baffles of FIGS. 3-6;

[0026] FIGS. 8 and 9 illustrate a mounting bracket for securing the plurality of baffles to the emitter;

[0027] FIG. 10 is a bottom perspective view illustrating another embodiment of an exemplary lighting apparatus of the present disclosure;

[0028] FIG. 11 is a perspective view of an emitter and reflector of the embodiment of FIG. 10, the reflector including a plurality of RF shielding baffles;

[0029] FIG. 12 is a side view of the emitter and reflector of FIG. 11; [0030] FIG. 13 is a bottom plan view of the emitter and reflector of FIG. 12 illustrating further details of the plurality of baffles situated around a bulb of the emitter;

[0031] FIGS. 14 and 15 illustrate one of the outer panels of the reflector of FIGS. 10-12;

[0032] FIGS. 16 and 17 illustrate inner RF shielding baffles of the reflector of FIGS. 10-12;

[0033] FIG. 18 is a bottom perspective view illustrating yet another embodiment of an exemplary lighting apparatus of the present disclosure;

[0034] FIG. 19 illustrates an additional inner RF baffle used in the embodiment of FIG. 18; and

[0035] FIG. 20 is a plan view of a bottom of a reflector housing including a conductive material covering portions of a window of the reflector housing.

[0036] FIG. 21 is a block diagram illustrating an exemplary light emitting plasma (LEP) lighting apparatus of the present disclosure;

[0037] FIG. 22 is a bottom, perspective view illustrating one embodiment of a LEP lighting apparatus of the present disclosure;

[0038] FIG. 23 is a perspective view illustrating an emitter and a radio frequency (RF) absorption plate coupled to the emitter surrounding a bulb of the emitter;

[0039] FIG. 24 is a side view of the emitter of FIG. 23;

[0040] FIG. 25 is a plan view of a bottom surface of the emitter of FIGS. 23 and 24 illustrating further details of the RF absorption plate;

[0041] FIG. 26 is a plan view of the RF absorption plate of FIGS. 22-25;

[0042] FIG. 27 is a bottom perspective view illustrating another embodiment of a LEP lighting apparatus of the present disclosure;

[0043] FIG. 28 is a plan view of a bottom surface of the emitter of the FIG. 27 embodiment illustrating further details of another RF absorption plate surrounding a bulb of the emitter;

[0044] FIG. 29 is a side view of the emitter of FIGS. 27 and 28;

[0045] FIG. 30 is a plan view of the RF absorption plate of FIGS. 27-29; [0046] FIG. 31 is a diagrammatical view of another embodiment of the RF absorption plate;

[0047] FIG. 32 is a diagrammatical view of yet another embodiment of the RF absorption plate; and

[0048] FIG. 33 is a plan view of a bottom of a reflector housing including a conductive material covering a portion of a window of the reflector housing.

[0049] Corresponding reference characters indicate corresponding parts throughout the several views. The drawings set out herein illustrate exemplary embodiments of the invention and such drawings are not to be construed as limiting the scope of the invention in any manner.

Detailed Description of the Drawings

[0050] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, which are described below. The embodiments disclosed below are not intended to be exhaustive or limit the present lighting system to the precise form disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. Therefore, no limitation of the scope of the lighting system is intended. The present lighting system includes any alterations and further modifications of the illustrated devices, systems and described methods and further applications of the principles of the present disclosure which would normally occur to one skilled in the art.

[0051] In an illustrated embodiment of the present disclosure, FIG. 1 illustrates an exemplary light emitting plasma (LEP) lighting apparatus 10. The lighting apparatus 10 includes an emitter 12 which receives a radio frequency (RF) signal from a power amplifier or driver 30. Driver 30 includes a microcontroller and a RF generator. The RF signal from driver 30 is input into a ceramic resonator or puck 14 having a cylindrically shaped, sealed quartz bulb 16. The puck 14 driven by the driver 30 creates a standing wave confined within its walls. An electric field of the standing wave is strongest at the center of the bulb 16 resulting in the ionization of the gasses inside the bulb 16. The ionized gas vaporizes contents of the bulb 16 into a plasma state at the center of bulb 16 to generate an intense source of light. Light is emitted from an outer surface of bulb 16 radially in all directions. As shown in FIG. 1, the light emitted by bulb 16 is directed by a reflector 18. Reflector 18 includes a window 20 is coupled to an opening of a reflector housing 22. Window 20 is made from glass or other suitable material which allows light to pass therethrough.

[0052] An exemplary emitter is model number STA 41-02 LEP emitter available from Luxim® located in Sunnyvale, California. Additional details regarding various components of lighting apparatus 10 are described in PCT International Publication No. WO/2012/031287, entitled LIGHTING APPARATUS, the disclosure of which is expressly incorporated by reference herein.

[0053] Driver 30 receives DC power from a power source or power converter 40. Power converter 40 receives AC power from an AC power supply 50, such as the grid, and rectifies the AC power to produce a DC power signal output from power converter 40.

[0054] Reflector 18 alters the direction of the light exiting bulb 16 to shape a desired illumination pattern on a spaced apart object. Exemplary spaced apart objects include the ground, floors, desktops, and other surfaces to be illuminated.

[0055] As best shown in FIG. 2, the driver 30 is part of a driver assembly 32. More particularly, the driver 30 is mounted in a driver housing 34. A heat sink block 36 is mounted to a side of driver housing 34 adjacent driver 30. Heat sink block 36 includes a body portion and a plurality of heat sink fins extending away from the body portion to dissipate heat from the driver 30. The driver 30 is illustratively coupled to the body portion of heat sink block 66 by suitable fasteners.

[0056] Power converter 40 including a plurality of heat sink fins 42 is mounted to an opposite side of driver housing 34 from driver 30 by suitable fasteners. Power converter 40 is illustratively an Inventronics Model EUV300S028ST. The power converter 40 is illustratively an IP67 (Ingess Protection) rated, 300W, 28V constant voltage supply, although any suitable power supply may be used. Inventronics is located in Hangzhou, China.

[0057] An emitter assembly 11 is pivotably coupled to the driver housing 34 by a suitable hinge connection 24 (see FIGS. 10 and 18) so that the emitter assembly 11 is moveable relative to the driver housing 34. As discussed above, the emitter assembly 1 1 includes an emitter 12 coupled to an opening in a top surface of reflector housing 22. Reflector housing 22 includes a bottom portion 24 defining an opening 26 spaced apart from the emitter 12. Window 20 is located over the opening 26. Reflector 18 includes an inner surface 28 which reflects light from the bulb 16 in a desired pattern from the reflector 18.

[0058] As best shown in FIGS. 3-6, the emitter 12 includes a body portion 60 having a plurality of heat sink fins 62 used to dissipate heat from the emitter 12. The puck 14 is located within the body portion 60 and is held in position with retainer clips 15 as best shown in FIG. 3. The bulb 16 is located on the bottom surface 64 of puck 14. Bulb 16 is held on puck 14 by first and second coupling portions 66 and 68.

[0059] As discussed above, the emitter 12 emits light from bulb 16 and a RF field from bottom surface 64 of puck 14. The RF field emitted by puck 14 in other directions is

substantially blocked by the metal body portion 60 of emitter 12. Conventional LEP lights use a conductive material such as a screen, mesh, coating or film covering the entire window 20 to absorb the RF field so that RF interference emitted by the LEP light is reduced. However, use of such a conductive material covering window 20 also reduces or occludes the light output from the lighting apparatus by about 15-20%.

[0060] The LEP lighting apparatus 10 of the present disclosure does not use a conductive material covering the entire window 20 in order to reduce the emitted RF field to an acceptable level. In certain illustrated embodiments of the present disclosure, the conductive material on the window 20 is eliminated. In other embodiments, a conductive material such as a screen, mesh, coating or film covers less than the entire window 20 to increase the amount of light emitted from lighting apparatus 10.

[0061] An illustrated embodiment of FIGS. 2-9 includes a plurality of planar RF shielding baffles 70 coupled to the body portion 60 of emitter 12 above the bottom surface 64 of puck 14. In an illustrated embodiment, a center baffle 70 is positioned at a 90° angle relative to the bottom surface 64 of puck 14 as shown by angle 72 in FIG. 5. Side baffles 70 are illustratively positioned at a 45° angle relative to the bottom surface 64 of puck 14 as shown by angles 74 and 76 of FIG. 5. The baffles 70 are oriented generally perpendicular to an outer surface of bulb 16 to minimize the light blocking effect of baffles 70 on light emitted by bulb 16. In other words, planar body portions 74 of baffles 70 are located in a plan extending radially away from bulb 16. The term "generally perpendicular" as used here means 80° - 100°, preferably 85° - 95°, and most preferably 90°.

[0062] An illustrative configuration of the baffles 70 is best shown in FIG. 7. Baffles 70 include a planar body portion 80 having first and second mounting tabs 82 and 84 extending from opposite ends 83 and 85, respectively, of body portion 80. An inner edge of body portion 80 includes a central recess 86 and first and second side recesses 87 and 88. The recesses 86, 87, and 88 are formed to fit over bulb 16 and coupling portions 66, and 68, respectively. Recess 86 provides a gap between bulb 16 and the body portion 80 of baffle 70 sized to reduce the likelihood of arching between the bulb 16 and the baffle 70.

[0063] In the illustrated embodiment, the plurality of baffles 70 are coupled to the emitter 12 by a pair of mounting brackets 90 best shown in FIGS. 8 and 9. The mounting brackets 90 include a base portion 92 having an aperture 94 formed therein. The aperture 94 is configured to receive a fastener therethrough to secure the mounting plate 90 to the body portion 60 of emitter 12 as best shown in FIG. 3.

[0064] Mounting brackets 90 include a mounting portion 96 extending upwardly from base 92. Mounting portion 96 includes a plurality of elongated apertures 98 configured to receive tabs 82 and 84 of baffles 70 to secure the baffles 70 to the mounting brackets 90. As best shown in FIG. 3, the tabs 82 and 84 fit within the elongated apertures 98 of mounting brackets 90 to hold the baffles 70 in the desired orientation. The width of tabs 82 and 84 and length of slots 98 prevent rotational movement of the baffles 70 relative to bottom surface 64 of puck 14.

[0065] Baffles 70 are formed from a suitable conductive material such as aluminum, for example. Baffles 70 are grounded so when the RF field from puck 14 strikes the baffles 70, RF energy is dissipated or absorbed by baffles 70. Baffles 70 allow energy from the incident radiated RF electromagnetic waves to be conducted to ground as an electrical current, thus minimizing the radiated RF electromagnetic waves that leave the fixture. Therefore, baffles 70 provide RF shields located between the emitter 12 and window 20 to reduce RF interference emitted from lighting apparatus 10. [0066] Another embodiment of the present disclosure is illustrated in FIGS. 10-17.

Components labeled with the same numbers as FIGS. 1-9 perform the same or similar function in this illustrated embodiment. In the embodiment of FIGS. 10-17, a plurality of RF absorption shields or baffles 130, 132 are coupled to reflector 18' inside reflector housing 22 as best shown in FIGS. 11 and 13. Reflector 18' is coupled to body portion 60 of emitter 12. Reflector 18' illustratively includes four outer panels 102 which are interconnected to form an outer periphery of the reflector 18'.

[0067] Outer panels 102 are best shown in FIGS. 14 and 15. Each outer panel 102 includes a body portion 104 having a bottom flange 106 and a central portion 108 extending upwardly at about a 45° angle relative to the bottom surface 64 of puck 14 as illustrated by angle 110 of FIG. 14. A top flange 112 is located at an opposite end of center portion 108 of each panel 102.

[0068] Each outer panel 102 includes ends 114 and 116 which are aligned at 45° angles as shown in FIG. 15. A pair of mounting tabs 118 extend away from end 114 of outer panels 102. The opposite end 116 of outer panels 102 are formed to include slots 120 configured to receive tabs 118 of an adjacent panel 102 to form the outer periphery of reflector 18'. Each of the outer panels 102 further includes slots 122 to connect the outer panels 102 to inner baffles 130 and 132 as best shown in FIGS. 16 and 17.

[0069] Inner baffle 130 best shown in FIG. 16 includes a planar body portion 134 having opposite ends 136 and 138. Mounting tabs 140 extend away from opposite ends 136 and 138 of body portion 134. A bottom edge 142 is formed to include notched portions or recesses 144, 146 and 148. Recess 144 is contoured so that body portion 134 is spaced apart from bulb 16 by a gap sized to reduce the likelihood of arching. Recesses 146 and 148 are configured to be located over fasteners coupled to body portion 60 of emitter 12. Inner baffle 130 further includes an elongated slot 150 extending upwardly from recess 144.

[0070] A second inner baffle 132 is best shown in FIG. 17. Inner baffle 132 includes a planar body portion 154 having first and second ends 156 and 158. Tabs 160 extend away from the first and second ends 156 and 158 of body portion 154. A bottom 162 of body portion 154 includes a central notched portion or recess 164, and additional notched portions or recesses 165, 166, 167, and 168. Central recess 164 and recesses 166 and 167 fit over bulb 16 and coupling portions 66 and 68, respectively. Body portion 154 is spaced apart from bulb 16 by recess 164 which defines a gap sized to reduce the likelihood of arching. Recesses 165 and 168 fit over fasteners coupled to body portion 60 of emitter 12. Inner baffle 132 includes a top edge 170 having a downwardly extending central slot 172 and first and second side slots 174 and 176. Side slots 174 and 176 are not necessary for embodiments with only two inner baffles 130 and 132 such as shown in FIGS. 10-17.

[0071] As best shown in FIG. 13, baffles 130 and 132 intersect directly over bulb 16. The slot 150 of baffle 130 is inserted over baffle 132 so that baffle 130 is located within slot 172 of baffle 132 to interconnect inner baffles 130 and 132 as shown in FIGS. 10, 11 and 13. Tabs 140 of baffle 130 and tabs 160 of baffle 132 extend through slots 122 in outer panels 102 as best shown in FIGS. 11 and 12 to secure the inner baffles 130 and 132 to the outer panels 102. Reflector 18' is formed by central portions 108 of outer panels 102 which are aligned at a 45° angle relative to the bottom surface 64 of puck 14. The baffles 130 and 132 are aligned perpendicular to the bulb 16 and the bottom surface 64 of puck 14 to minimize interference of the baffles 130 and 132 with light emitted from bulb 16.

[0072] Baffles 130 and 132 and outer panels 102 are formed from a suitable conductive material, such as aluminum, to absorb RF energy emitted from emitter 12 that strikes the baffles 130 and 132. Panels 102 and baffles 130 and 132 are grounded so that RF interference emitted from the lighting apparatus 10 is reduced.

[0073] Another embodiment of the present invention is illustrated in FIGS. 18 and 19. In this illustrated embodiment, additional inner RF shields or baffles 180 are coupled to inner baffles 130 and 132. The additional inner baffles 180 are best shown in FIG. 19. Baffles 180 each include a planar body portion 182 having first and second ends 184 and 186. Body portion 182 is formed to include apertures 188 located near end 184. Tabs 190 are configured to extend from end 186 of baffles 180. Body portion 182 includes a bottom edge 192 having an upwardly extending elongated slot 194. Slots 194 of baffles 180 are positioned over baffles 130 and 132. In an illustrated embodiment, slots 194 are aligned with slots 174 and 176 of baffle 132 so that inner baffles 180 are aligned at an angle of about 60° relative to bottom surface 64 of puck 14. However, planar body portions 182 of baffles 180 are aligned perpendicular to an outer surface of bulb 16 to minimize the blocking effect of baffles 180 on light emitted by the bulb 16. Baffle 130 may also have slots 174 and 176. Tabs 190 from one inner baffle 180 are located within slots 188 of an adjacent inner baffle 180 to form an interconnected matrix of RF absorption baffles 180 best shown in FIG. 17.

[0074] Another embodiment of the present disclosure is illustrated in FIG. 20. FIG. 20 is similar to FIG. 13. However, the housing 22 of reflector 18' is shown in FIG. 20. As discussed above, window 20 is coupled to the bottom portion 24 of housing 22 so that the window 20 is located over the opening 26 in reflector 18'. The use of RF shields or baffles 70, 130, 132, and 180, for example, reduces the RF field emitted from lighting apparatus 10 without fully covering the window 20 with a conductive screen, mesh, film or coating. In certain illustrated

embodiments, no conductive mesh, screen, film or coating is used on the window 20. In other embodiments, the window 20 is provided with conductive portions 200 which cover less than the entire window 20. Four such conductive portions 200 are illustrated in FIG. 20. In a further embodiment, the window 20 is fully covered with a conductive portion 200. However, the conductive portion 200 has a higher light transmission factor (such as a mesh with fewer openings per inch and/or finer wires) than conductive material used in conventional plasma lights without the RF shielding baffles of the present disclosure. For example, if a conventional light fixture uses a conductive mesh having an 80 OPI (openings per inch) rating, the same light fixture including the RF baffles 70, 130, 132, and/or 180 of the present disclosure may use a conductive mesh having a rating of 50 OPI. Therefore, these embodiments achieve similar RF shielding with a higher light output than is achieved through the use of the lower light transmission RF shielding mesh alone.

[0075] In illustrated embodiments, the baffles 70, 130, 132, and 180 substantially reduce the RF field emitted from the lighting apparatus 10. However, in the FIG. 20 embodiment, certain selected portions of the window 20 are covered with the conductive mesh, screen, film or coating (referred to as conductive portions 200) to further reduce RF emissions from targeted areas of the reflector 18'. In embodiments where the conductive material 200 is used, the conductive material 200 is electrically coupled to an outer conductive path 202 extending around the periphery of reflector 18'. Illustratively, the conductive material portions 200 are connected to outer conductive path 202 by conductive portions 204. The conductive path 202 is grounded to provide a ground connection to conductive material 200 on window 20.

[0076] Illustratively, the reflectors 18 and 18' containing RF shielding baffles 70, 130, 132 and/or 180 are analyzed to determine if any portions of the reflector are emitting higher than desired RF fields. If so, the conductive material 200 is selectively placed on targeted portions of the window 20. Therefore, the combined coverage area of the conductive portions 200 is less than an overall area of the entire window 20 to increase the amount of light emitted through the window 20 compared to windows that are fully covered with a conductive material.

[0077] In an illustrated embodiment of the present disclosure, FIG. 21 illustrates an exemplary light emitting plasma (LEP) lighting apparatus 1010. The lighting apparatus 1010 includes an emitter 1012 which receives a radio frequency (RF) signal from a power amplifier or driver 1030. Driver 1030 includes a microcontroller and a RF generator. The RF signal from driver 1030 is input into a ceramic resonator or puck 1014 having a sealed quartz bulb 1016. The puck 1014 driven by the driver 1030 creates a standing wave confined within its walls. An electric field of the standing wave is strongest at the center of the bulb 1016 resulting in the ionization of the gasses inside the bulb 1016. The ionized gas vaporizes contents of the bulb 1016 into a plasma state at the center of bulb 1016 to generate an intense source of light. As shown in FIG. 21, the light emitted by bulb 1016 is directed by a reflector 1018. Reflector 1018 includes a window 1020 is coupled to an opening of a reflector housing 1022. Window 1020 is made from glass or other suitable material which allows light to pass therethrough.

[0078] An exemplary emitter is model number STA 41-02 LEP emitter available from Luxim® located in Sunnyvale, California. Additional details regarding various components of lighting apparatus 1010 are described in PCT International Publication No. WO/2012/031287, entitled LIGHTING APPARATUS, the disclosure of which is expressly incorporated by reference herein.

[0079] Driver 1030 receives DC power from a power source or power converter 1040.

Power converter 1040 receives AC power from an AC power supply 1050, such as the grid, and rectifies the AC power to produce a DC power signal output from power converter 1040. [0080] Reflector 1018 alters the direction of the light exiting bulb 1016 to shape a desired illumination pattern on a spaced apart object. Exemplary spaced apart objects include the ground, floors, desktops, and other surfaces to be illuminated.

[0081] As best shown in FIG. 22, the driver 1030 is part of a driver assembly 1032. More particularly, the driver 1030 is mounted in a driver housing 1034. A heat sink block 1036 is mounted to a side of driver housing 1034 adjacent driver 1030. Heat sink block 1036 includes a body portion and a plurality of heat sink fins extending away from the body portion to dissipate heat from the driver 1030. The driver 1030 is illustratively coupled to the body portion of heat sink block 1066 by suitable fasteners.

[0082] Power converter 1040 including a plurality of heat sink fins 1042 is mounted to an opposite side of driver housing 1034 from driver 1030 by suitable fasteners. Power converter 1040 is illustratively an Inventronics Model EUV300S028ST. The power converter 1040 is illustratively an IP67 (Ingess Protection) rated, 300W, 28V constant voltage supply, although any suitable power supply may be used. Inventronics is located in Hangzhou, China.

[0083] An emitter assembly 1011 is pivotably coupled to the driver housing 1034 by a suitable hinge connection (not shown) so that the emitter assembly 1011 is moveable relative to the driver housing 1034. As discussed above, the emitter assembly 1011 includes an emitter 1012 coupled to an opening in a top surface of reflector housing 1022. Reflector housing 1022 includes a bottom portion 1024 defining an opening 1026 spaced apart from the emitter 1012. A window 1020 is located over the opening 1026. Reflector 1018 includes an inner surface 1028 which reflects light from the bulb 1016 in a desired pattern from the reflector 1018.

[0084] As best shown in FIGS. 23-26, the emitter 1012 includes a body portion 1060 having a plurality of heat sink fins 1062 used to dissipate heat from the emitter 1012. The puck 1014 is located within the body portion 1060 and is held in position with retainer clips (not shown). The bulb 1016 is located on the bottom surface 1064 of puck 1014. Bulb 1016 is held on puck 1014 by first and second coupling portions 1066 and 1068.

[0085] As discussed above, the emitter 1012 emits light from bulb 1016 and a RF field from bottom surface 1064 of puck 1014. The RF field emitted by puck 1014 in other directions is substantially blocked by the metal body portion 1060 of emitter 1012. Conventional LEP lights use a conductive material such as a screen, mesh, coating or film covering the entire window 1020 to absorb the RF field so that RF interference emitted by the LEP light is reduced.

However, use of such a conductive material covering window 1020 also reduces or occludes the light output from the lighting apparatus by about 15-20%.

[0086] The LEP lighting apparatus 1010 of the present disclosure does not use a conductive material covering the entire window 1020 in order to reduce the emitted RF field to an acceptable level. In certain illustrated embodiments of the present disclosure, the conductive material on the window 1020 is eliminated. In other embodiments, a conductive material such as a screen, mesh, coating or film covers less than the entire window 1020 to increase the amount of light emitted from lighting apparatus 1010.

[0087] In an illustrated embodiment best shown in FIGS. 23-26, a radio frequency (RF) shielding plate 1070 is coupled to the body portion 1060 of emitter 1012 by suitable fasteners 1072 so that the plate 1070 is positioned over the bottom surface 1064 of puck 1014 (see FIG. 25). In the illustrated embodiment, a spacer 1071 is located between the body portion 1060 of emitter 1012 and plate 1070 to provide a gap between the planar RF shielding plate 1070 and the planar bottom surface 1064 of puck 1014. Illustratively, the gap has a dimension sized to reduce the likelihood of arching between the plate 1070 and the bulb 1016. In another illustrated embodiment, the RF shielding plate 1070 is coupled directly over bottom surface 1064 of puck 1014 without a spacer 1071.

[0088] RF shielding plate 1070 includes a planar body portion 1074 having a central aperture 1076 formed therein. The planar body portion 1074 of RF shielding plate 1070 is aligned parallel to the bottom surface 1064 of puck 1014 and covers the entire bottom surface 1064 except for the portion of the bottom surface 1064 located adjacent aperture 1076.

[0089] As best shown in FIG. 26, the central aperture 1076 is contoured to match a shape of bulb 1016. Specifically, aperture 1076 includes an enlarged central portion 1078 sized larger than bulb 1016 to leave a gap between plate 1070 and a periphery of bulb 1016 to reduce the likelihood of arching between the bulb 1016 and the plate 1070. Illustratively, the gap has a dimension sized to reduce the likelihood of arching between the plate 1070 and the bulb 1016. Aperture 1076 also includes end portions 1080 and 1082 extending away from central portion 1078. Portions 1080 and 1082 of aperture 1076 are located adjacent bulb coupling portions 1066 and 1068, respectively, as best shown in FIG. 25.

[0090] As also shown in FIG. 26, body portion 1074 of RF shielding plate 1070 further includes apertures 1084 aligned with mounting apertures formed in body portion 1060 of emitter 1012. The apertures 1084 receive fasteners 1072 therethrough to couple the plate 1070 to body portion 1060 of emitter 1012 as shown in FIG. 25.

[0091] As discussed above, an RF field is emitted from bottom surface 1064 of puck 1014 during operation of the LEP lighting apparatus 1010. The RF shielding plate 1070 is made of a suitable conductive material, such as aluminum, which is grounded to provide an RF shield over the bottom surface 1064 of puck 1014. RF shielding plate 1070 permits light to pass from bulb 1016 through aperture 1076 to reflector 1018 and window 1020. The grounded RF shielding plate absorbs portions of the RF field emitted by emitter 1012 which strike the body portion 1074 of plate 1070. This reduces the RF field emitted by lighting apparatus 1010.

[0092] In one illustrated embodiment, the typical conductive material such as a screen, mesh, film or coating on window 1020 is omitted to increase the amount of light provided by lighting apparatus 1010. In another embodiment, discussed below with reference to FIG. 33, a conductive material is applied to selected portions of window 1020 to provide further RF shielding for the lighting apparatus 1010.

[0093] Another embodiment of the present disclosure is illustrated in FIGS. 27-30. Those elements referenced by numbers identical to FIGS. 21-26 perform the same or similar function. As best shown in FIG. 30, RF shielding plate 1170 includes a planar body portion 1174 formed to include a generally rectangularly shaped central aperture 1176. Body portion 1174 further includes mounting apertures 1184 configured to receive fasteners 1072 to secure the RF shielding plate 1170 to the body portion 1060 of emitter 1012 over the bottom surface 1064 of puck 1014 as shown in FIG. 28. In the illustrated embodiment of FIGS. 27-30, the RF shielding plate 1170 is coupled directly over bottom surface 1064 of puck 1014 without a spacer. In another embodiment, a spacer 1071 is located between the body portion 1060 of emitter 1012 and plate 1170 to provide a gap between plate 1170 and the bottom surface 1064 of puck 1014. The planar body portion 1174 of RF shielding plate 1170 is aligned parallel to the bottom surface 1064 of puck 1014 and covers the entire bottom surface 1064 except for the portion of the bottom surface 1064 located adjacent aperture 1176.

[0094] As best shown in FIGS. 28 and 29, the central aperture 1176 of body portion 1 174 is sized to expose the bulb 1016 and first and second coupling portions 1066 and 1068 of bulb 1016. Portions of the bottom surface 1064 of puck 1014 of emitter 1012 are covered by the plate 1170 to absorb portions of the RF field emitted by emitter 1012 which contact the RF shielding plate 1170. The size of central aperture 1176 is selected during manufacture to optimize the transmission of light and absorption of the emitted RF field, while maintaining an appropriate gap between the plate 1170 and the bulb 1016 to reduce the likelihood of arching between the bulb 1016 and the plate 1170. Therefore, other suitable shapes may be used for the aperture 1176 in other embodiments.

[0095] In another illustrated embodiment shown in FIG. 31, a RF shielding plate 1270 is coupled to the emitter 1012 by suitable fasteners as discussed above. A spacer 1271 defines a gap 1272 between the RF shielding plate 1270 and a bottom surface 1064 of puck 1014. A body portion 1274 of plate 1270 includes a central aperture 1276 configured to expose the bulb 1016. In the embodiment of FIG. 31, inner portions of the plate 1270 defining aperture 1276 are bent to define an edge 1278 configured to contact the bottom surface 1064 of puck 1014. The configuration of FIG. 31 eliminates a gap 1272 between the bottom surface 1064 of puck and the RF shielding plate adjacent the aperture 1276 and surrounding bulb 1016 to increase absorption of portions of the RF field emitted by puck 1014 of emitter 1012.

[0096] Another embodiment of the present disclosure is shown in FIG. 32. Those elements referenced by numbers identical to FIG. 31 perform the same or similar function. In the FIG. 32 embodiment, the inner edge 1278 of plate 1270 defining aperture 1276 is bent to define a curved contacting portion 1280. The curved contacting portion 1280 provides a smooth surface for engaging the bottom surface 1064 of puck 1014. Contacting portion 1280 surrounds bulb 1016 to increase absorption of portions of the RF field emitted by puck 1014 of emitter 1012.

[0097] Another embodiment of the present disclosure is illustrated in FIG. 33. As discussed above, a window 1020 is coupled to the bottom portion 1024 of reflector housing 1022 to cover opening 1026. In illustrated embodiments, the RF shielding plates 1070, 1170 or 270 substantially reduce the RF field emitted from the lighting apparatus 1010. Therefore, in certain illustrated embodiments, no conductive mesh, screen, film or coating is used on the window 1020.

[0098] In other embodiments, the window 1020 is provided with one or more conductive material portions 1200 which cover less than the entire window 1020. In the FIG. 33

embodiment, a portion of the window 1020 is covered with the conductive material such as a mesh, screen, film or coating (referred to as conductive material 1200) to further absorb and reduce RF emissions from a targeted area of the reflector 1018. Conductive material 1200 is electrically coupled to an outer conductive path 1202 extending around the periphery of reflector 1018 by conductive portions 1204. The conductive path 1202 is grounded to provide a ground connection to conductive material 1200 on window 1020.

[0099] In a further embodiment, the window 1020 is fully covered with a conductive material 1200. However, the conductive material 1200 has a higher light transmission factor (such as a mesh with fewer openings per inch and/or finer wires) than conductive material used in conventional plasma lights without the RF shielding plate 1070, 1170 or 270 of the present disclosure. For example, if a conventional light fixture uses a conductive mesh having an 80 OPI (openings per inch) rating, the same light fixture including the RF plate 1070, 1170 or 270 of the present disclosure may use a conductive mesh having a rating of 50 OPI. Therefore, these embodiments achieve similar RF shielding with a higher light output than is achieved through the use of the lower light transmission RF shielding mesh alone.

[00100] Illustratively, the reflector 1018 containing one of the RF shielding plates 1070, 1170 or 270 is analyzed to determine if any portions of the reflector are emitting higher than desired RF fields. If so, conductive material 1200 is selectively placed on targeted portions of the window 1020. Therefore, the conductive material 1200 covers less than an entire area of window 1020 to increase the amount of light emitted through the window 1020 compared to windows fully covered with conductive material.

[00101] The present disclosure includes an exemplary method of reducing the RF field produced from a light emitting plasma lighting apparatus. The light emitting plasma lighting apparatus includes a plasma bulb, a window, and a reflector which receives light from the plasma bulb and directs the light through the window. The method comprises the steps of positioning at least one RF shielding baffle between the plasma bulb and the window; and grounding the baffle to absorb a portion of the RF field emitted by the light emitting plasma lighting apparatus. In one example, the at least one baffle extends from a periphery of the reflector towards a center of the reflector. In a variation thereof, the RF shielding baffle includes a planar body and the method further comprises the step of aligning the planar body to be generally perpendicular to an outer surface of the plasma bulb to minimize interference with light emitted from the plasma bulb. In another example, the RF shielding baffle includes a planar body and the method further comprises the step of aligning the planar body to be generally perpendicular to an outer surface of the plasma bulb to minimize interference with light emitted from the plasma bulb. In a further example, the RF shielding baffle is reflective.

[00102] While this disclosure has been described as having exemplary designs and embodiments, the present system may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains.