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  Solid state led bridge rectifier light engineUSPTO Application #: 20070069663Title: Solid state led bridge rectifier light engine Abstract: A solid-state light engine comprised of light emitting diodes (LEDs) configured into a bridge rectifier with a current limiting module coupled to the LED bridge rectifier. The light engine may be packaged for high temperature operation. Optionally, the LEDs comprise wavelength-converting phosphors with a persistence that is a multiple of the peak to peak current period, to smooth and mask ripple frequency pulsation of emitted light. (end of abstract)
Agent: Patent Docket Administrator Lowenstein Sandler PC - Roseland, NJ, US Inventors: Robert J. Burdalski, Joseph B. Mazzochette USPTO Applicaton #: 20070069663 - Class: 315312000 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20070069663. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/685,680, filed May 27, 2005, the entire disclosure of which is hereby incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Embodiments of the invention relate to a solid-state light engine that is directly compatible with alternating current (AC) input power, without the need for a separate rectification module, but that can also alternatively be powered by direct current (DC) input power. [0004] 2. Related Art [0005] In many lighting applications, solid-state light engines are superior to conventional incandescent lamps. Beneficially, solid-state light engines can, in certain circumstances, achieve an almost 20% improvement in efficiency and an extended lifetime (e.g. exceeding 50,000 hours) as compared to incandescent lamps. [0006] Traditional solid-state light engines are powered by a direct current or pulsating direct current drive. As such, to drive the light engine using an AC power source, the AC input line must first be conditioned. Power-conditioning commonly involves the rectification of AC input power, typically achieved by inserting rectifier diodes in a bridge configuration, as well as a means of limiting current, such as a series resistance or reactance in the power path. However, the addition of such electronic components into the power path may increase manufacturing costs and complexity, and can cause a decrease in the lifetime (or time to failure) of the light engine, and can decrease efficiency due to power loss. [0007] To avoid the performance-related issues caused by the insertion of power conditioning elements into the power path, some standard solid-state light engines are powered directly from the AC line. However, the direct AC powering of a light engine causes the light output to pulsate at the frequency of the AC power source, typically in the range of 50 to 60 Hz. This line frequency pulsation can produce eye fatigue or annoyance when viewed, even in cases where the engine is viewed for a short period of time. [0008] Accordingly, there is a need for a solid state light engine that is directly compatible with an AC input power source, which does not exhibit the deleterious pulsation effects generated by a direct AC powering arrangement, and/or which does not require the use of separate power conditioning or rectification circuitry. SUMMARY OF THE INVENTION [0009] Embodiments of the invention satisfy these and other needs. Embodiments of the invention relate to a solid state bridge rectifier light engine arrangement that may be powered directly by an AC input line, without the need for further power conditioning. Although full-wave bridge rectifiers are known in the art, they utilize non-light emitting diodes, and are used to convert AC current to DC current for use as a power source for external electronic components, not to produce useful illumination. Similarly, although the use of LEDs for illumination is known in the art, LEDs are typically powered by a DC power source. The present invention advantageously uses LEDs in a novel way by configuring them into a bridge rectifier to produce useful light directly from an AC power source without the need for separate rectification or other conditioning of the input power. [0010] More specifically, embodiments of the invention provide for a solid state light engine arrangement that includes a full wave bridge rectifier configuration of light emitting diodes (LEDs) directly compatible with an AC power input, which may advantageously also be connected to a current limiting element. An added benefit to this configuration is that the light engine may be constructed with two sets of terminals for connection to a power source, so that the user has the option of powering the light engine by either AC power or the more traditional DC power, depending on the terminals to which the user connects the power source. [0011] Embodiments of the invention can also include a solid-state LED bridge rectifier circuit advantageously using phosphors to further smooth any frequency pulsation or ripple of light emitted from the light engine. The LED bridge rectifier can include one or more LEDs configured such that the LED bridge rectifier receives and rectifies an AC power signal and emits light. The current limiting module can be used to protect the LEDs by limiting the current passing through the LEDs within the LED bridge rectifier. The LEDs can emit any of a number of colors of light, depending on the type of LED used. Advantageously, LEDs that emit of blue and/or ultraviolet wavelength emissions can be used, in combination with wavelength converting phosphors known in the art, to create light that is perceived as white light by a user. See, for example, U.S. Pat. No. 5,998,925 to Shimizu. The converting phosphor can be particles of Cerium activated Yttrium Aluminum Garnet (YAG:Ce) or Europium activated Barium Orthosilicates (BOSE). [0012] The turn-on and turn-off time for typical LEDs is in the tens to one hundred nanosecond range. With this response time, LEDs will virtually follow the low frequency AC waveform without delay. According to an aspect of an embodiment of the invention, through rectification, the light pulsation or ripple frequency will typically be increased to approximately twice the frequency of the input AC line current (e.g., 100 to 120 Hz). This frequency doubling has the advantageous effect of speeding up the light pulsation to a frequency beyond what is typically perceptible to human observers, thus making it more appealing for use in standard lighting applications than would an LED array powered directly from AC current that was not configured into a bridge rectifier. In addition, the frequency doubling that occurs in the LED bridge rectifier configuration results in a shortening of the time duration between current peaks to about 10 ms for a 50 Hz line and about 8 ms for a 60 Hz line. The shortened peak to peak period, together with the advantageous use of phosphors having a persistence of 5 to 10 times that duration, masks the light pulsation or flicker, allowing it to be smoothed and integrated into a nearly continuous white light output. Phosphors having a longer or shorter persistence may also be used advantageously. [0013] The light engine arrangement according to certain embodiments of the invention can be used as a solid-state replacement for conventional Edison-base incandescent lamps or as a replacement for low-voltage halogen lamps or other low voltage lamps. Advantageously, since no additional electronic components need be inserted into the power path, the increased useful life offered by the solid state light engine need not be compromised. BRIEF DESCRIPTION OF THE DRAWINGS [0014] The invention can be understood from the detailed description of exemplary embodiments presented below, considered in conjunction with the attached drawings, of which: [0015] FIG. 1 is a basic schematic of a solid state light engine in accordance with embodiments of the invention; [0016] FIG. 2 is a more detailed schematic of a solid state light engine, in accordance with embodiments of the invention; [0017] FIG. 3 is a circuit diagram of a solid state light engine, in accordance with embodiments of the invention; [0018] FIG. 4 is a graphical representation of the emissions of various structures; [0019] FIG. 4a is a diagram showing alternative exemplary dispositions of phosphor particles for use with LEDs in the present invention; [0020] FIG. 5 is a circuit diagram of a solid state light engine, in accordance with embodiments of the invention; Continue reading... Full patent description for Solid state led bridge rectifier light engine Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Solid state led bridge rectifier light engine patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Solid state led bridge rectifier light engine or other areas of interest. ### Previous Patent Application: Current-balancing circuit for lamps Next Patent Application: Switched constant current driving and control circuit Industry Class: Electric lamp and discharge devices: systems ### FreshPatents.com Support Thank you for viewing the Solid state led bridge rectifier light engine patent info. 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