Patent Application
20140092596
1. Field of the Invention
The present invention relates to light sources, and more particularly to solid state light sources.
2. Description of the Related Art
Electric light sources have been used for almost two hundred years to illuminate spaces such homes, offices, and exterior spaces. Light sources commonly include components such as: a light fixture, a housing, a driver circuit, a lamp, and a lens. A single light source may have multiple light fixtures, housings, driver circuits, lamps, and lenses.
Light fixtures are commonly designed to enclose a housing, lamp, and lens. The light fixture may contain dedicated space for electrical wiring. For instance, a suspended light fixture may contain a hollow pole for electrical wiring to connect the lamp and an outside source of power. Light sources are frequently installed on walls or ceilings or suspended from ceilings. Several light sources may be electrically and/or mechanically connected. Light sources are also frequently installed in free standing table or floor lamps. In particular, fluorescent lights are often used in light sources, placed end-to-end, in order to light hallways, large rooms, and other spaces. The housing for a light source may be visible, installed in a base, such as an Edison base, or may be recessed within a ceiling or wall.
Light fixtures may be constructed to provide different types of lighting effects such as downlights, uplights, wall washers, and grazers. These effects may be provided by a variety of fixture types such as cove lights, pendant lights, recessed lights, and sconces. Multiple light fixtures may be mechanically coupled together. Light fixtures that have been mechanically coupled together may consist of multiples of the same fixture, or a variety of different fixtures. However, in the prior art when fluorescent-based light sources were coupled together, for example, they suffered from the drawback of requiring a break in the light to accommodate ballasts, wiring, and other necessary hardware components.
Light fixtures contain one or more sources of illumination, i.e., lamps. Incandescent, fluorescent, high-intensity discharge, and more recently light emitting diodes (LEDs), among other types of illuminating components, are used within a light fixture as the lamp. Electrically speaking, the light emitting portion of the light source may be referred to as the load.
Optical structures are often used to enhance, direct, and otherwise alter the light emitted from the lamp. One such effect is microdiffusion. Current techniques of creating microdiffusion for lenses include creating a microdiffusion surface on a film through processes such as photolithography and photoengraving. Such films are then applied to other optical structures to diffuse light emitted from the light source.
The disclosed subject matter relates to a light source. The light source includes a heat sink including a central cavity and at least one wall enclosing a portion of the central cavity; a printed circuit board (PCB) disposed in the central cavity of the heat sink, the PCB having a driver circuit disposed on a first side of the PCB and a plurality of lamps substantially surface-mounted on an opposing side of the PCB, wherein the plurality of lamps are operably connected to the driver circuit, wherein each of the plurality of lamps is a semi-spherical solid state lamp, the PCB further having a connector that can be operably connected to a power source; and a first optical structure in operable registration with at least one of the plurality of lamps.
The light source may further include an optical structure for a plurality of lamps, wherein each lamp is a semi-spherical solid state lamp, wherein the optical structure emits substantially shadowless, substantially homogeneous, and substantially monochromatic light, the optical structure including: a plurality of first optical elements, each associated with one of the plurality of lamps for substantially collimating the light emitted from the associated one of the plurality of lamps to form a substantially collimated beam; and a second optical element associated with each of the plurality of first optical elements such that each of the plurality of second optical elements receives a portion of the substantially collimated beam and provides multiple optical images of the collimated beam, wherein the focal point of each of the multiple optical images formed by the plurality of second optical elements have a focal point that is practically infinite.
The subject matter of the invention further regards a light source with an optical structure including an inner surface, an outer surface, and a body disposed between the inner and outer surfaces, wherein the inner surface is disposed toward a plurality of lamps, wherein each lamp is a semi-spherical solid state lamp; a plurality of first optical elements each having a column shaped cavity extending into the body from the inner surface, the column shaped cavity terminating in a convex surface, the opposite distal end of each column shaped cavity being operably associated with a respective one of the plurality of lamps; and a second optical element for each of the plurality of first optical elements, each second optical element including a plurality of protrusions having a substantially hexagonal base and a spherical cap, wherein each second optical element abuts at least two other second optical element, where the microdiffusion texture may be configured to create a five degree spread and is created in the outer surface of the optical structure via an injection mold process.
The light source may include a third optical element including a microdiffusion texture formed in the outer surface of the optical structure. The microdiffusion texture may be configured to create a five degree spread. The microdiffusion texture is created in the outer surface of the optical structure via an injection mold process. The optical structure may have a microdiffusion texture that is based on fractal geometry. The optical structure may further include multiple protrusions for each of the second optical elements each including twelve facets. Each of the plurality of lamps of the light source may include a light-emitting diode. The plurality of lamps be either three lamps or six lamps. The first optical element may collimate the light of each lamp to a fixed diameter.
The disclosed subject matter further includes an optical structure including an inner surface, an outer surface, and a body disposed between the inner surface and the outer surface, wherein the inner surface is proximate to a plurality of lamps wherein each lamp is a semi-spherical solid state lamp and wherein the plurality of lamps are linearly arranged; a first optical element having a cavity extending into the body from a rectangular opening of the inner surface having a concave surface facing the inner surface for each of the plurality of lamps; and a second optical element including a plurality of total internal reflection (TIR) elements formed on the outer surface extending along a length of the outer surface across the plurality of lamps.
The optical structure may further include a second optical structure separated from the first optical structure by a fixed distance, the second optical structure having a first side, a second side, and a body disposed between the first side and the second side, wherein the first side is proximate to the plurality of lamps; a third optical element disposed in a portion of the first side of the second optical structure directing light from the plurality of lamps to a fixed degree of spread; and a fourth optical element including a microdiffusion texture formed in the second side of the second optical structure. The optical structure may include a microdiffusion pattern configured to create a five degree spread. The microdiffusion pattern may be created in the second side of the second optical structure via a roller press. The optical structure may include the fixed degree of spread as one of ten degrees, thirty degrees, forty-five degrees, sixty degrees, or one hundred twenty degrees. The optical structure may include the plurality of TIR elements of the second optical element that are shaped such that exiting light is evenly spread to an angle corresponding to a width of the second optical structure at the fixed distance from the first optical structure. The second optical structure may be formed by an extrusion process.
The subject matter of the disclosure further includes a light source including a housing; a lamp disposed within the housing, wherein the lamp load is a semi-spherical solid state lamp presenting a lamp load to a driver circuit; and the driver circuit disposed within the housing operatively connected to the lamp load, the driver circuit including an alternating current (AC) to direct current (DC) power converter circuit receiving input power having a duty cycle from a power supply and outputting a DC power output including a ripple voltage having a magnitude that is ratiometrically determined by the duty cycle and the lamp load; a peak detector circuit receiving the DC power output from the AC to DC power converter circuit and removing a DC offset; and a constant current circuit receiving the output of the peak detector circuit and the current through the lamp load and varying the current delivered by the constant current circuit to the lamp load based on the ripple component.
The light source may further include the output of the peak detector circuit as an average of the DC power output from the AC to DC power converter over a plurality of duty cycles of the input power. The constant current circuit of the light source may reduce the current delivered to the lamp load when the average output of the peak detector circuit falls below a threshold voltage. The duty cycle of the input power of the light source may be influenced by one of a triode for alternating current (TRIAC) and a silicone control rectifier (SCR). The light source may further include an optical structure disposed within the housing. The optical structure of the light source may be formed by injection molding and wherein the optical structure includes an optical element comprising a microdiffusion pattern molded directly onto a surface of the optical structure. The light source may include an Edison-type base.
The subject matter of the disclosure further regards a driver circuit for a light source including a lamp, wherein the lamp comprises a semi-spherical solid state lamp and presents a lamp load to the driver circuit, the driver circuit including an alternating current (AC) to direct current (DC) power converter circuit receiving input power having a duty cycle from a power supply and outputting a DC power output including a ripple voltage having a magnitude that is ratiometrically determined by the duty cycle and the lamp load; a peak detector circuit receiving the DC power output from the AC to DC power converter circuit and removing a DC offset; and a constant current circuit receiving the output of the peak detector circuit and the current through the lamp load and varying the current delivered by the constant current circuit to the lamp load based on the ripple component.
The driver circuit of the light source may have the output of the peak detector circuit as an average of the DC power output from the AC to DC power converter over a plurality of duty cycles of the input power. The constant current circuit may reduce the current delivered to the lamp load when the average output of the peak detector circuit falls below a threshold voltage. The duty cycle of the input power may be influenced by one of a triode for alternating current (TRIAC) and a silicone control rectifier (SCR).
The subject matter of the disclosure further includes a driver circuit for a light source including a plurality lamps, wherein each lamp comprises a semi-spherical solid state lamp presenting a lamp load to the driver circuit, the driver circuit including an alternating current (AC) to direct current (DC) power converter circuit receiving input power having a duty cycle from a power supply and outputting a DC power output including a ripple voltage having a magnitude that is ratiometrically determined by the duty cycle and the lamp load; a peak detector circuit receiving the DC power output from the AC to DC power converter circuit and removing a DC offset; and a constant current circuit receiving the output of the peak detector circuit and the current through the plurality of lamp loads and varying the current delivered by the constant current circuit to the plurality of lamp loads based on the ripple component.
The driver circuit may include the output of the peak detector circuit as an average of the DC power output from the AC to DC power converter over a plurality of duty cycles of the input power. The constant current circuit may reduce the current delivered to the lamp load when the average output of the peak detector circuit falls below a threshold voltage. The duty cycle of the input power is influenced by one of a triode for alternating current (TRIAC) and a silicone control rectifier (SCR).
The subject matter of the disclosure further regards a light source including a plurality of lamps, wherein each lamp comprises a semi-spherical solid state lamp, the light source including a heat sink including a central cavity and at least one wall enclosing a portion of the central cavity; a printed circuit board (PCB) disposed in the central cavity of the heat sink, the PCB having a driver circuit disposed on a first side of the PCB and a plurality of lamps substantially surface-mounted on an opposing side of the PCB, each of the plurality of lamps operatively connected with the driver circuit so as to present a lamp load to the driver circuit, the PCB further having a connector that can be operably connected to a power source, wherein the driver circuit includes an alternating current (AC) to direct current (DC) power converter circuit receiving input power from a power supply and outputting a DC power output; a dimming control circuit receiving input power having a duty cycle and a maximum output power value and outputting a dim control signal based on the duty cycle of the input power and the maximum output power value; and a constant current circuit receiving the dim control signal and feedback based on the current through the plurality of lamp loads and varying the current delivered by the constant current circuit to the plurality of lamp loads based on the dim control signal; and a first optical structure in operable registration with at least one of the plurality of lamps.
The dim control signal of the light source may be limited by the maximum output power and further limited by the duty cycle of the input power. The feedback may be further limited by a maximum power output limit. The light source may be electrically connected to a second driver circuit wherein the current delivered by each of the constant current circuits is based on the dim control signal of the driver circuit determined to be a master driver circuit. The PCB may include at least one frangible section, each frangible section having at least one of the plurality of lamp loads substantially surface-mounted thereon and a pre-perforated border to facilitate breakaway of the frangible section from the PCB while allowing operable electrical connection between the at least one of the plurality of lamp loads and the driver circuit via a solid-state switch, the gate of the solid-state switch being biased into conduction by the voltage across the at least one of the plurality of lamp loads disposed on the frangible section. The number of lamp loads connected to the driver circuit of the light source may be variable, wherein the last of the plurality of lamp loads is operably connected to the driver circuit via a solid-state switch forward biased by a voltage drop across one of the plurality of lamp load.
The subject matter of the disclosure includes a driver circuit for a light source including a plurality of lamps, wherein each lamp comprises a semi-spherical solid state lamp presenting a lamp load to the driver circuit, the driver circuit comprising an alternating current (AC) to direct current (DC) power converter circuit receiving input power from a power supply and outputting a DC power output; a dimming control circuit receiving input power having a duty cycle and a maximum output power value and outputting a dim control signal based on the duty cycle of the input power and the maximum output power value; and a constant current circuit receiving the dim control signal and feedback based on the current through the plurality of lamp loads, the constant current circuit varying the current delivered by the constant current circuit to the plurality of lamp loads based on the dim control signal.
The dim control signal of the driver circuit may be limited by the maximum output power and further limited by the duty cycle of the input power. The feedback of the driver circuit may be further limited by a maximum power output limit. The driver circuit may be electrically connected to a second driver circuit. The current delivered by each of the constant current circuits is based on the dim control signal of the driver circuit determined to be a master driver circuit. The PCB of the light source may include at least one frangible section, each frangible section having at least one of the plurality of lamp loads substantially surface-mounted thereon and a pre-perforated border to facilitate breakaway of the frangible section from the PCB while allowing operable electrical connection between the at least one of the plurality of lamp loads and the driver circuit via a solid-state switch, the gate of the solid-state switch being biased into conduction by the voltage across the at least one of the plurality of lamp loads disposed on the frangible section. The number of lamp loads of the light source of the plurality of lamp loads connected to the driver is variable, wherein the last of the plurality of lamp loads is operably connected to the driver circuit via a solid-state switch forward biased by a voltage drop across one of the plurality of lamp loads. The number of lamp loads of the plurality of lamp loads connected to the driver of the light source may be variable, wherein the last of the plurality of lamp loads is operably connected to the driver circuit via a solid-state switch forward biased by a voltage drop across one of the plurality of lamp loads.
The subject matter of the disclosure further regards a method for providing a light source of flexible length including a plurality of lamps, wherein each lamp comprises a semi-spherical solid state lamp, the method including providing a heat sink including a central cavity and at least one wall enclosing a portion of the central cavity; providing a printed circuit board (PCB) disposed in the central cavity of the heat sink, the PCB having a driver circuit disposed on a first side of the PCB, the PCB having a plurality of lamps substantially surface-mounted on an opposing side of the PCB, the PCB having an alterable length such that the length is determined by breaking off the PCB at increments, wherein each increment includes at least one of the plurality of lamps, each of the plurality of lamps operatively connected with the driver circuit so as to present a lamp load to the driver circuit, the PCB further having a connector that can be operably connected to a power source, wherein the driver circuit includes an alternating current (AC) to direct current (DC) power converter circuit receiving input power from a power supply and outputting a DC power output; a dimming control circuit receiving input power having a duty cycle and a maximum output power value and outputting a dim control signal based on the duty cycle of the input power and the maximum output power value; and a constant current circuit receiving the dim control signal and the current across the plurality of lamp loads and varying the current delivered by the constant current circuit to the plurality of lamp loads based on the dim control signal; and providing a first optical structure in operable registration with at least one of the plurality of lamps.
The dim control signal of the method may be limited by the maximum output power and further limited by the duty cycle of the input power. The feedback may be further limited by a maximum power output limit. The method may additionally include providing an electrical connection to a second driver circuit. The current delivered by each of the constant current circuits in the method may be based on the dim control signal of the driver circuit determined to be a master driver circuit. The method may include a the lamp load nearest the broken end of the PCB that is operably connected to the driver circuit via a solid-state switch forward biased by a voltage drop across one of the plurality of lamp loads.
These and other objects and advantages of the present disclosure will be apparent to those of ordinary skill in the art having the present drawings, specifications, and claims before them. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the disclosure, and be protected by the accompanying claims.
The invention may be better understood by references to the detailed description when considered in connection with the accompanying drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
While the present disclosure may be embodied in many different forms, the drawings and discussions are presented with the understanding that the present disclosure is an exemplification of the principles of one or more inventions and is not intended to limit any one of the inventions to the embodiments illustrated. It is understood that the specific order or hierarchy of steps in disclosed methods and processes may be rearranged. Steps may be performed simultaneously or all disclosed steps may not be performed without departing from the scope of the subject technology.
Light source 110 includes light fixture 115 and heat sink 112. In a preferred approach to the lighting system for deployment in room 10, light sources 120, 130, and 140 are designed around heat sinks that are substantially identical to heat sink 112. By creating a line of light sources that have common sub-components, like heat sink 112, the potential complexity in assembling multiple types of light sources as well as the component inventory may be substantially reduced. In addition to interchangeable heat sink 112, light sources may include other common sub-components such as optical structures and driver circuitry on printed circuit boards (PCBs). In a similar vein, the heat sink 112 as well as optical structures and PCBs may be comprised of multiple components in a modular assembly to accommodate a variety of desired fixture lengths leading to even further room design flexibility. Interchangeability of components additionally provides efficient and streamlined upgradeability of components such as driver circuits contained on PCBs. Thus, upgrades in driver circuitry or other changes to the light sources after installation may be performed by interchanging parts without the aid of a skilled technician.
Light fixture 210a of
As shown in
In the exemplary embodiment of the subject invention of
Unlike the heat sinks shown in previous figures, the heat sinks 410e, 410f and 410g, 410h, 410i, 410j, and 410k are configured with dual central cavities to accommodate drivers, lamps, and optical structures on two sides. Each cavity is shaped identically such that the drivers lamps and optics of the subject technology may be modularly installed on each side. Each of the dual central cavities may be independently wired so as to provide independent lighting on either side. For example, one of the dual cavities may be installed with lighting that is designed to be used with a generator during power outages. In another example, opposing sides of the heat sinks 410e-410k may be separately wired such that an uplight may be controlled separately from a downlight, including separate dimming capabilities. The dual cavity heat sinks reduce the space required to use two separate heat sinks by sharing a common side of the heat sink. Accordingly, light fixtures built to accommodate only single sided heat sinks are not interchangeable with dual sided heat sinks due to the increased height of the dual sided heat sinks. However, light fixtures built to accommodate dual sided heat sinks may be adapted for use with single sided heat sinks. The heat sinks 410b, 410c, 41d, 410f, 410g, 410h, 410i, 410j, and 410k may include additional respective side portion(s) 420b, 420c, 420d, 420f, 420g, 420h, 420i, 420j, and 420k to facilitate the use of one or more different fixtures of different shapes, particularly for use with pendant mounted light sources. Any of the heat sinks 410 may additionally or alternatively include a side mount section 430h to facilitate use with wall mounted light sources. Heat sinks may be additionally shaped such that a left portion 420 differs in shape from a respective right portion of 420.
As illustrated in
Lamps 530 disposed on PCB 520 are preferably semi-spherical solid state lamps. For example, the lamps may be light emitting diodes (LEDs), such as Cree® XLamp® XB-D White LED and Cree® XLamp® XM-L LED lamps. It will be understood that other solid state lamps (preferably semi-spherical) may be used with the subject technology without departing from the intended scope of the present invention.
The PCB 520 further contains holes such that a first optical structure 550 may be mounted in operable physical registration with one or more lamps 530 disposed in PCB 520. First optical structure 550 may be secured in operable physical registration with the PCB using one or more pin fasteners 560. As illustrated, pin fastener 560 may be constructed of nylon, acrylic or any other suitable material. Any other type of fastener may be used so long as operable physical registration can be maintained between first optical structure 550 and the lamps 530 mounted on PCB 520 via mechanical engagement between the first optical structure 550 and the PCB 520. The first optical structure 550 may be operably aligned with the lamps 530 of PCB 520 using pins 555. Pins 555 are preferably formed integrally with first optical structure 550 and, thus, will be made of the same material as the first optical structure 550.
The driver circuit will be disposed on the one side of the PCB 520 intended to be installed facing the inner side of the top wall of the heat sink 112 leaving the plurality of lamps substantially surface-mounted on the opposite side of the PCB opposing the driver circuit. The lamps would be disposed in the PCB face such that they align with one of the openings in first optical structure 550. As illustrated in
So, as collectively illustrated by
The use of internal reflection and the calibration of the optical effects in the first optical structure 250 preferably provide greater efficiency than can be achieved by structures previously known in the art. As illustrated in
First optical structure 250 includes two optical elements. The term “optical element” as used herein encompasses its plain and ordinary meaning, including, but not limited to one or more surfaces of an optical structure that are shaped and sized to produce an optical effect when light is transmitted through the optical structure. Multiple optical elements may be configured on a single optical structure such that multiple lamps may be used together in a single optical structure to produce the desired effect. The first optical element acts as a total internal reflection (TIR) optical element. This optical element significantly collimates light emitted from the lamp associated with that element (i.e. there is a single lamp to single TIR relationship). This optical element furthers a preferred goal of the invention by efficiently collimating a significant portion of the light emitted by the solid-state lamps. The TIR optical element includes cavities 610, each with a rectangular opening extending into optical structure 250. The termination surface 660 of each cavity 610 has a concave surface, that is the interior termination of each cavity 610 is a “U” shaped trough. Cavities 610 and termination surfaces 660 are sized and shaped such that the emitted light is collimated to create even illumination down the length of the optical element at a fixed width.
Fin protrusions 650 function as a second optical element and are disposed on the opposing side of the first optical structure 250 furthest from the lamps. Fin protrusions 650 run substantially the length of the optical structure with substantially uniform cross-sections throughout the length of optical structure 250.
Optical structure 700 may be made through an extrusion process. Optical effect on surface 720 may preferably be formed as part of the extrusion process in which optical structure 700 is created.
As the type of optical effect provided by the second optical structure will not be visible to the naked eye during installation (and before operation), the protrusions 810a and 810b are preferably shaped to communicate to an installer the optical effect provided by a particular structure based on a shape of the protrusions. One particular scheme for providing these visual cues to the installers is illustrated in
As would be understood by those of ordinary skill in the art having the present specification and drawings before them, the protrusions 810a and 810b need not be shaped as illustrated in the
Several optical structures may be used in a single light source, or several light sources may be grouped together. The length of the optical structure may be made in a series of parts to facilitate customization of light effects for a room. The width of the optical structure may be uniform, regardless of optical effect, to facilitate the interchangeability of the optical structures and to maximize the ability to customize light sources for a particular environment. Optical effects may also be varied to create an aesthetically pleasing effect or to follow the structure of the room, such as accommodation of windows, doorways, or other structural elements of a room. Thus, the installation of light sources for a room may use a variety of optical structures in a single room. Identifiable protrusions on the optical element thus reduce the time required to install, change, or replace optical elements by providing an easily identifiable optical effect and additionally reduces the occurrence.
Each of the optical structures 900, 1000, and 1100 of
A second optical element of the optical structure is comprised of protrusions 950, 1050, and 1150 on the side of the optical structure opposite the first optical element. Multiple protrusions 950, 1050, and 1150 form the second optical element for each of the lamps of each light source. Each second optical element receives the collimated light from the first optical element and emits multiple optical images with substantially infinite focal points. Each optical image emitted by the second optical element corresponds to each of the protrusions 950, 1050, and 1150. Multiple protrusions 950, 1050, and 1150 make up each second optical element. Each protrusion 950, 1050, and 1150 has two stages. The first stage of each protrusion 950, 1050, and 1150 extends from a hexagonal base on the surface of the optical structures 900, 1000, and 1100 outward and away from the respective lamps. As illustrated in
By way of example (and not limitation), twelve protrusions 950, 1050, and 1150 may be used for each lamp in a three lamp configuration. The surface of optical structures 900, 1000, and 1100 containing the second optical elements for each lamp may be further formed such that each plane substantially disposed over each lamp is tilted towards the central axis. The illustrations of
A third optical element of each of the optical structures 900, 1000, and 1100 are disposed on the surfaces of the protrusions 950, 1050, and 1150 of the second optical elements. Although this microdiffusion texture is present on each of the optical structures 900, 1000, and 1100, the microdiffusion texture is shown only in the detail
The combined effect of the three optical elements of the optical structure results in a substantially shadowless, substantially homogeneous, and substantially monochromatic light. The optical structure may contain additional optical elements. The optical structure may be used in tandem with one or more additional optical structures to provide further optical effects. The optical structure may be disposed within the housing, which is disposed in the light source. The optical structure may be in registration with a structure on which the lamps are disposed, such that the lamps are in registration with the first optical element.
The topography of the second optical element is subtractively formed into the die using an electric discharge machining (EDM) process in S1230. Each protrusion 950, 1050, and 1150 is sized and shaped to provide a total spread of the light source. For example, the total spread of the light source may be configured to provide a fifteen degree spread, a twenty-four degree spread, a forty-five degree spread, or the like. These exemplary spread angles are generally achieved with optical equations. The spread angle of the resulting optical structure may be determined by measuring from a central axis to an outer edge of the light emitted from the optical structure. The size of the base and the number of protrusions may be chosen such that the light emitted from each lamp is substantially received by the input of the second optical element. Following an initial EDM process, sample optical elements may be produced and tested. Further refinement is performed to accommodate the individual materials and tools. Additional EDM processes and further testing are performed to achieve the desired spread.
The microdiffusion pattern is created in an inner surface of the mold by laser etching the diffusion pattern into the appropriate surface of the mold in S1240 such that the microdiffusion pattern will be integrally formed on the surface of the protrusions 950, 1050, and 1150 following creation of the mold. The topography of the microdiffusion texture may be determined based on fractal geometry equations.
The diffusion texture is integrally formed via laser in the optical structure through the injection mold process furthering yet another goal of efficient manufacture of the optical structure. The depth of the pattern is determined. One exemplary depth is 10-12 micron for a 100 micron diameter diverging beam, which provides a microdiffusion texture with 5-7 degree scatter. The divergence degree s(x) can be used to determine the vertex radius of curvature (R) where c=1/R and K is a conic constant:
The angles of the laser are dependent on the materials, temperature of the environment, and type of laser. The process of determining the appropriate angles of the laser can be determined through the resulting optical structures by using a measuring the light emitted from the optical structure using a laser of a known wavelength as the light source and taking optical measurements of the emitted light. Test patterns can be burned on a sample block of the same steel as the mold and measured for reflected beam scatter when sourced by a visible laser to determine laser settings. The 50% scatter angle needs to be greater from the tool as the structure will not be entirely transferred to the molded part, the percentage scatter angle is dependent on the mold materials. A laser surface path can be made using existing Rhinoceros® Software and implemented using GF AgieCharmilles® (GFAC) LASER 1200 5Ax. Prior to lasering the microdiffusion pattern, the mold cavity can be polished to a minor finish, with a machining index of a 0 or 1. Since the diffusion will also be on the mold cavity after laser processing, the laser energy can be based on the diffusion as reflected light image from the processed surface. Image transfer from the most to the plastic will be affected by shrinkage of the plastic during cooling as well as the mold flow of the plastic. Optical structures can then be manufactured in S1240 using the completed mold.
Once manufactured, the optical structures are checked for correct microdiffusion patterns both mechanically and optically. Mechanical checks may be performed by sectioning the part. A shallow microdiffusion pattern is indicative of a mold that has not been completely packed, or poor material image transfer indicating a need to revise the burn settings. Optical testing can be performed using a laser beam projected through the optical part at a screen to manually observe the resulting scatter pattern.
The AC-to-DC power converter circuit 1210 receives the alternating current (AC) line voltage, which can be thought to have a duty cycle that may be varied by a dimmer circuit (not shown) such that the duty cycle of the AC line voltage would be approximately 100% where there is no dimmer circuit or the dimmer is full on and, thus, not altering the firing phase angle. The AC-to-DC power converter circuit 1210 not only converts from alternating to direct current, but is designed to convert VA (volts/Amps) into a DC power with peak watts where the AC conversion is set to meet the load requirement for 2-3 solid state light sources at minimum input voltage. A capacitor C6 is a filter cap for the transformer T3.
Transformer T3 in circuit 1200 is a flyback transformer because of the higher energy storage with large variation of input voltage capabilities in the magnetic circuit provided by that type of transformer. When combined with switch M4 for voltage spike suppression T3 can re-circulate its stored power back into the full wave DC that is then applied to the transformer on the next switch cycle. This results in a small boost (mostly when the input voltage is below the secondary voltage times the turns ratio of T3) providing the additional voltage to the flyback transformer for power transfer even at low AC phase angles and when the dimmer has a low DC offset. As shown in
On the secondary of transformer T3 (
The dimming control circuit 1220 receiving input power having a duty cycle and a maximum output power value and outputting a dim control signal based on the duty cycle of the input power and the maximum output power value. In a preferred embodiment, the dimming control circuit 1220 is based on a programmed 8-bit microprocessor, U8, such as the ATtiny25 (an 8-bit AVR RISC-based microcontroller combines 2 KB ISP flash memory, 128B EEPROM, 128B SRAM with general purpose I/O lines, general purpose working registers, an 8-bit timer/counter (with compare mode), 8-bit high speed timer/counter, external/internal interrupts, and an A/D converter).
Microprocessor U8 is programmed with code that provides the ability to dim the solid-state lights by thyrister dimming (e.g. triac), 0-10V analog and series digital signals by one or more sources where the fixture is self-configuring to respond to multiple diming signals. This ability allows a building control (not shown) to set a maximum dimming level and still allow the local dimming of individual fixtures and/or rooms by local thyrister-based wall dimmers. This dual control enables load shed controlling by the building controls and still allows users to dim conference rooms /offices when required.
The interface to the building control uses a standard analog signal (0-10 v) or digital protocols which can be wired or wireless (e.g. zigbee, DALI, DMX). The building control signal is read to determine the maximum percentage dimming. The maximum set point established by the building control is compared to the phase dimming signal created by measurement of the AC waveform. In particular, the input AC signal is received as a half or full wave rectified signal. The rectified signal is placed thru a comparator set to the highest typical hold voltage for Triac dimmers. The square wave generated contains the dimming percentage as a width change on the waveform. This waveform is passed to the microcontroller U8, which is shown as being optically isolated from the circuit by opto-coupler U7. It should be understood by those of ordinary skill in the art having the present specification before them that microcontroller U8 may be non-isolated. Using this resulting waveform as an edge trigger microprocessor U8 counts the number of present timer intervals. This count is used to determine the phase diming.
The set point determined in from the building control is compared to the phase diming percentage count, whichever is lower is used to set the pulse width modulated diming. The building lighting control always maintains the peak illumination for both load shedding and occupancy time. The end points are where phase diming is 100% on and the building diming is 1%, here the AC-to-DC conversion is functioning normal with the feedback in control. The other extreme is the phase diming is 5% and the building diming is 100% on. For this the PWM needs to respond quickly to reduce the chance of LED flicker. Since the power in the AC mains may drop faster than the circuit can “dim-down” the circuit—using the averaging approach adopted in the circuitry—when the secondary bulk DC drops below an expected minimum voltage, the PWM moves to less than the phase angle value. Once the voltage recovers the LED will increase level to the percentage determined.
A local occupancy sensor can be another input as a switch toggle along with a local ambient light sensor. The occupancy toggle will define the PWM as max or off. Like the prior comparison this data can also be compared. The same is held for the light sensor which can also provide a signal that dims the led by providing the lowest diming percentage. An
example of the hierarchal dimming working in a priority, the highest is the occupancy sensor, next phase diming, then ambient light and last building diming.
The ability to dim individual LED drivers exists but can create issues in fixtures where multiple LED drivers exist that can dim parts of fixtures. Where the dimming signal is digital, analog or phase diming the individual LED drivers may convert the dimming data provided into different LED drive currents where the result is each led segment can be at a different illumination level when diming occurs. This can occur with any of the dimming control method, the method with the most error is phase diming as this is not an absolute signal but a signal derived from the manipulation of the AC phase. To correct for this issue communication between LED drivers could be added at a fixture level to provides direct control over the LED drive current. This communication is the drive current data and not the higher level building data or phase data, as the drivers may be controlled by multiple dimming methods 0-10, DALI, Zigbee, Occupancy sensor, the LED drive current can be controlled at the lowest level with one driver determining the diming from one or multiple sources and the remaining driver listening and responding only.
As phase dimming begins the average of the ripple begins to drop as seen across the DC output capacitance (i.e. C17) since the load is constant at this point. Once the six cycle average drops below the set point, the LED drive current is reduced. In reality, because there is a tolerance on the capacitance and a few other set point determining components the drive current may not change for 10-20 degrees of phase dimming, and this is required to ensure peak lumen output occurs on all lamps. As the average drops followed by a drop in the LED current, the system will begin to attain a median point and the LED drive current will become proportional to the ripple.
The AC-to-DC power converter circuit 1210 receives the alternating current (AC) line voltage, which can be thought to have a duty cycle that may be varied by a dimmer circuit (not shown) such that the duty cycle of the AC line voltage would be approximately 100% where there is no dimmer circuit or the dimmer is full on and, thus, not altering the firing phase angle. The AC-to-DC power converter circuit 1210 not only converts from alternating to direct current, but is designed to convert VA (volts/Amps) into a DC power with peak watts where the AC conversion is set to meet the load requirement for 2-3 solid state light sources at minimum input voltage. A capacitor C6 is a filter cap for the transformer T3.
Transformer T3 in circuit 1200 is a flyback transformer because of the higher energy storage capabilities in the magnetic circuit provided by that type of transformer. When combined with switch M4 for voltage spike suppression T3 can re-circulate its stored power back into the full wave DC that is then applied to the transformer on the next switch cycle. This results in a small boost (mostly when the input voltage is below the secondary voltage times the turns ratio of T3) providing the additional voltage to the flyback transformer for power transfer even at low AC phase angles and when the dimmer has a low DC offset. As shown in
On the secondary of transformer T3 (
The circuitry in
The AC-to-DC power converter circuit 1510 receives the alternating current (AC) line voltage, which can be thought to have a duty cycle that may be varied by the dimmer circuit 50 such that the duty cycle of the AC line voltage would be approximately 100% where there is no dimmer circuit or the dimmer is full on and, thus, not altering the firing phase angle. The AC-to-DC power converter circuit 1510 not only converts from alternating to direct current, but is designed to convert VA (volts/Amps) into a DC power with peak watts where the AC conversion is set to meet the load requirement for 2-3 solid state light sources at minimum input voltage.
The AC-to-DC power converter circuit 1510 has an input stage running from terminals J1 and J2 to the primary windings of transformer T1. The primary is preferably designed to keep the full bridge rectifier in a forward conducting mode to increase the power efficiency of the circuit. Inductance L5 and L7 in combination with capacitor C6 form a non-dissipating snubber circuit.
Transformer T1 in circuit 1500 is preferably a flyback transformer because of the higher energy storage capabilities in the magnetic circuit of that type of transformer. When combined with switch M4 for voltage spike suppression T1 can re-circulate its stored power back into the full wave DC that is then applied to the transformer on the next switch cycle. This results in a small boost (mostly when the input voltage is below the secondary voltage times the turns ratio of T1) providing the additional voltage to the flyback transformer for power transfer even at low AC phase angles and when the dimmer 50 has a low DC offset. As shown in
On the secondary of transformer T1, a DC power output is produced with a ripple voltage. As such, the DC secondary includes capacitance (i.e. C17 and C57) that is sized to create a determinable ripple when the AC input voltage and the solid state light load are both at their maximum (e.g. 2-3 LEDs). Since solid state lamps operate in a fixed voltage range at a fixed line frequency, the ripple across this capacitance can be determined when a known power load (i.e., a lamp load) is applied. The ripple voltage has a ratiometrically determined magnitude that is determined by the duty cycle of the AC line voltage and the lamp load. The ripple is low pass filtered by C2 and R2 to remove all switch-mode noise and switching mode voltage transients from the ripple voltage. This voltage is the supply voltage to voltage regulator U9. Preferably, voltage regulator U9 is a high-current voltage regulator from the L78L00 family manufactured by STMicroelectronics. However, as those of ordinary skill in the art having the present specification before them would understand, other regulators may be used.
The peak detector circuit 1520 receives the filtered DC power output from the secondary of transformer from the AC to DC power converter circuit. In the embodiment shown in
As phase dimming begins the average of the ripple begins to drop as seen across the DC output capacitance (i.e. C17/C57) since the load is constant at this point. Once the six cycle average drops below the set point, the LED drive current is reduced. In reality, because there is a tolerance on the capacitance and a few other set point determining components the drive current may not change for 10-20 degrees of phase dimming, and this is required to ensure peak lumen output occurs on all lamps. As the average drops followed by a drop in the LED current, the system will begin to attain a median point and the LED drive current will become proportional to the ripple.
Since the dimming can occur faster than the six cycle limit there is a bucking diode, D49, that will conduct when the ripple average begins to drop by more than one volt from the peak average. The inclusion of this bucking diode is not required, but it does improve the dim down rate to better match the change in AC power available during a change in phase dimming. The diode (which may be a Zener) can be selected as desired to increase the diming down ramp. In circuit 1500 the nominal values have been preferably selected to result in a 33% minimum rate of change. Any change beyond that value will be handled by the diode with a rapid reduction in LED drive current.
In the converse case where the illumination is being increased, there is no need for any quick change feature. The average may be simply updated and the drive current increased. As before if the LED drive current begins to draw excessive current from the integrating capacitor the average reduces and then the LED drive current reduces.
The constant current circuit 1550 receives the output of the peak detector circuit 1520 and the current flowing through the lamp load, which is operably connected to the driver circuit 1500 via terminals J3 and J4. The constant current circuit 1550 is implemented in driver circuit 1500 by LED Driver U7. LED Driver U7 is preferably a CPC9909 manufactured by Clare, Inc. (www.clare.com). The CPC9909 has a dedicated input for a low-frequency pulse width modulated dimming control signal, which is operably connected to the output of the peak detector circuit. The current flowing through the lamp load is presented to the microprocessor as the voltage drop across R68. The microprocessor varying the current delivered by the constant current circuit to the lamp load based on the ripple component.
The AC-to-DC power converter circuit 1610 receives the alternating current (AC) line voltage, which has an input stage running from fuse F1 to the primary windings of transformer T3. Two full-bridge rectifier (formed by D8/D5/D4/D1) supply a full wave rectified DC voltage to the primary of T3 through a non-dissipating snubber circuit formed by inductors L5 and L7 in combination with capacitor C6. The primary of transformer T3 is preferably operably connected to a power factor correction circuit 1605 through semiconductor switch M4. In particular, power factor correction circuit 1605 may be designed around U4 (which may preferably be a NCL30000 power factor corrected dimmable LED Driver with switch mode power supply).
On the secondary of transformer T3, the DC power output is fed through a low-pass filter (formed by C2 and R2) to substantially remove switch-mode noise and switching mode voltage transients. This filtered DC output power supplies voltage to voltage regulator U2 that produces a 12V supply, which in turn supplies voltage regulator U3 that produces a 5V supply. Preferably, voltage regulators U2 and U3 are both from the L78L00 family manufactured by STMicroelectronics. As would be understood by those of ordinary skill in the art having the present specification before them would understand, other regulators may be used and other voltages may be provided.
The DC power output from the secondary of transformer T3 is also used to drive the constant current circuit 1650. Constant current circuit 1650 receives the output of the dimming control circuit 1620 and the current flowing through the lamp load, which is operably connected to the driver circuit 1600 via terminals 2 and 4 of jumper J8. The constant current circuit 1650 is implemented in driver circuit 1600 primarily by LED Driver U9. LED Driver U9 is preferably a CPC9909 manufactured by Clare, Inc. (www.clare.com). The CPC9909 has a dedicated input for a low-frequency pulse width modulated dimming control signal, which is operably connected to an output of the dimming control circuit. The current flowing through the lamp load is presented to U9 as the voltage drop across R70. The LED driver U9 varies the current delivered by the constant current circuit to the lamp load based on the values of the signals from the dimming control circuit applied to the gates marked PWMD (pulse width modulation input) and LD (linear dimming).
The dimming control circuit 1620 receiving input power having a duty cycle and a maximum output power value and outputting a dim control signal based on the duty cycle of the input power and the maximum output power value. In a preferred embodiment, the dimming control circuit 1620 is based on a programmed 8-bit microprocessor, U8, such as the ATtiny25 (an 8-bit AVR RISC-based microcontroller combines 2 KB ISP flash memory, 128B EEPROM, 128B SRAM with general purpose I/O lines, general purpose working registers, an 8-bit timer/counter (with compare mode), 8-bit high speed timer/counter, external/internal interrupts, and an A/D converter).
Microprocessor U8 is programmed with code that provides the ability to dim the solid-state lights by thyrister dimming (e.g. triac), 0-10V analog and series digital signals by one or more sources where the fixture is self-configuring to respond to multiple diming signals. This ability allows a building control (not shown) to set a maximum dimming level and still allow the local dimming of individual fixtures and/or rooms by local thyrister-based wall dimmers. This dual control enables load shed controlling by the building controls and still allows users to dim conference rooms /offices when required.
The interface to the building control uses a standard analog signal (0-10 v) or digital protocols which can be wired or wireless (e.g. zigbee, DALI, DMX). The building control signal is read to determine the maximum percentage dimming. The maximum set point established by the building control is compared to the phase dimming signal created by measurement of the AC waveform. In particular, the input AC signal is received as a half or full wave rectified signal. The rectified signal is placed thru a comparator set to the highest typical hold voltage for Triac dimmers. The square wave generated contains the dimming percentage as a width change on the waveform. This waveform is passed to the microcontroller U8, which is shown as being optically isolated from the circuit by opto-coupler U7. It should be understood by those of ordinary skill in the art having the present specification before them that microcontroller U8 may be non-isolated. Using this resulting waveform as an edge trigger microprocessor U8 counts the number of present timer intervals. This count is used to determine the phase diming.
The set point determined in from the building control is compared to the phase diming percentage count, whichever is lower is used to set the pulse width modulated diming. The building lighting control always maintains the peak illumination for both load shedding and occupancy time. The end points are where phase diming is 100% on and the building diming is 1%, here the AC-to-DC conversion is functioning normal with the feedback in control. The other extreme is the phase diming is 5% and the building diming is 100% on. For this the PWM needs to respond quickly to reduce the chance of LED flicker. Since the power in the AC mains may drop faster than the circuit can “dim-down” the circuit—using the averaging approach adopted in the circuitry—when the secondary bulk DC drops below an expected minimum voltage, the PWM moves to less than the phase angle value. Once the voltage recovers the LED will increase level to the percentage determined.
A local occupancy sensor can be another input as a switch toggle along with a local ambient light sensor. The occupancy toggle will define the PWM as max or off. Like the prior comparison this data can also be compared. The same is held for the light sensor which can also provide a signal that dims the led by providing the lowest diming percentage. An example of the hierarchal dimming working in a priority, the highest is the occupancy sensor, next phase diming, then ambient light and last building diming.
The ability to dim individual LED drivers exists but can create issues in fixtures where multiple LED drivers exist that can dim parts of fixtures. Where the dimming signal is digital, analog or phase diming the individual LED drivers may convert the dimming data provided into different LED drive currents where the result is each led segment can be at a different illumination level when diming occurs. This can occur with any of the dimming control method, the method with the most error is phase diming as this is not an absolute signal but a signal derived from the manipulation of the AC phase. To correct for this issue communication between LED drivers could be added at a fixture level to provides direct control over the LED drive current. This communication is the drive current data and not the higher level building data or phase data, as the drivers may be controlled by multiple dimming methods 0-10, DALI, Zigbee, Occupancy sensor, the LED drive current can be controlled at the lowest level with one driver determining the diming from one or multiple sources and the remaining driver listening and responding only.
The present system provides for the coordinated dimming throughout a room. The various driver circuits 1600 found on each light fixture are connected to each other via the ribbon cabling and connector J5. When the microprocessor U8 first powers up, it will look to see whether any other microprocessor has adopted the master role. If another microprocessor has taken the master role in the system, then the current microprocessor adopts the slave role, taking the calculation of dimming level from the master microprocessor. If no other microprocessor is sending the master signal, then microprocessor U8 will designate itself the master.
The foregoing description and drawings merely explain and illustrate the invention and the invention is not limited thereto. While the specification in this invention is described in relation to certain implementation or embodiments, many details are set forth for the purpose of illustration. Thus, the foregoing merely illustrates the principles of the invention. For example, the invention may have other specific forms without departing from its spirit or essential characteristic. The described arrangements are illustrative and not restrictive. To those skilled in the art, the invention is susceptible to additional implementations or embodiments and certain of these details described in this application may be varied considerably without departing from the basic principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements, which, although not explicitly described or shown herein, embody the principles of the invention and, thus, are within its scope and spirit. All publication patents and patent applications described herein are incorporated by reference in their entirety.
This application claims priority to U.S. Provisional Patent Application No. 61/707,771, filed Sep. 28, 2012, which is incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61707771 | Sep 2012 | US |
