LED retrofit module for roadway fixture

A solid state replacement light module for a high intensity discharge light fixture. The module is comprised of an elongated generally planar body having a first side including a plurality of light emitting diodes and a second side including a plurality of heat dissipating fins. The second side further includes an electronic module. The body also includes a hinge mechanism suitable for attachment to the light fixture.

BACKGROUND

Exterior lighting is used to illuminate roadways, parking lots, yards, sidewalks, public meeting areas, signs, work sites, and buildings, to name a few examples. Traditionally, such lighting systems used high-intensity discharge (HID) lamps, often high pressure sodium (HPS) lamps. The move towards improved energy efficiency has brought to the forefront light emitting diode (LED) technology as an alternative to HID lighting in commercial and municipal applications. LED lighting has the potential to provide improved energy efficiency and improved light output in outdoor applications.

The Cobra Head type light fixture is perhaps the most commonly found style of roadway fixture. It would be advantageous to convert existing Cobra Head style HID lamps to LED light sources without having to discard the entire fixture assembly. There is therefore a need for an improved LED retrofit solution for outdoor applications that does not require replacement of the existing fixture.

With reference toFIG. 1, a typical roadway lighting fixture is depicted. The Cobra Head lighting fixture1comprises a housing3having a central longitudinal axis “L”. The housing3includes a center section5arranged about the center longitudinal axis “L” of the housing3and running substantially along one half the length of the longitudinal axis of the housing3. The center section5defines a forward compartment enclosing an HID lamp7and a reflector9. The compartment is accessed via a door (not shown) hinged to a bottom surface of the fixture to provide access to the compartment from below. Typically, the door includes an opening receiving a lens through which light generated by the HID lamp7exits the fixture1. A rear section11of the housing3defines a rearward compartment housing a power supply13such as a ballast. The rear compartment also receives post15. A second door (not shown) is provided to cover the power supply13and provide independent access thereto. Alternatively, a single door is provided which is hingedly connected to the fixture1and provides access to center section5and rearward section11when opened.

According to one available LED retrofit system a replacement LED light source can be installed as follows. First, the door of an existing roadway illuminaire is opened, the existing HID lamp, reflector and lens are removed and recycled. Optionally, the existing ballast and other electrical components can be similarly removed. An LED light engine is then installed into the opening in the door from which the lens was removed. A safety cable is installed between the LED light engine and a main body of the fixture. Power leads are attached between the LED light engine and the power leads of the light fixture. Thereafter, the fixture door is closed and latched to achieve final installation of the LED luminaire. Although functional, this design can suffer from thermal management issues.

The present disclosure is directed to an improved simple and economic LED module for replacement of an HID lamp in an outdoor fixture.

BRIEF DESCRIPTION

According to a first embodiment, a solid state replacement light module for a high intensity discharge light fixture is provided. The module is comprised of an elongated general planar body. The body has a first side including a plurality of light emitting diodes and a second side including an electronics module. The body further includes a means for rotatable attachment to the light fixture.

According to a second embodiment, a method of retrofitting a roadway lamp fixture is described. The method comprises providing an LED inclusive door which is cooperatively shaped and sized relative to an opening in the lamp fixture. The LED inclusive door includes a first side with a plurality of light emitting diodes and a second side including an electronics module. An existing door is removed from the fixture at its hinged connection to the fixture and the LED inclusive door is installed to the fixture at the hinged connection. The electronics module is connected to the fixture power lines.

According to a third embodiment, a method of retrofitting a roadway lamp fixture is provided. The method comprises removing existing roadway lamp, fixture door, removing a lamp and electronics suitable for driving the lamp from the fixture. Further steps include installing electronics suitable for driving a plurality of light emitting diodes, connecting the electronics to a power line within the fixture and installing a door including a plurality of light emitting diodes which is sized substantially the same as the removed existing door. An electrical connection between the electronics suitable for driving the light emitting diodes and the plurality of light emitting diodes is also established.

DETAILED DESCRIPTION

The present disclosure provides a convenient and economical device for the replacement of an HID light source in a light fixture. The disclosure finds particular relevance to roadway fixtures, such as the commonly employed Cobra Head style. Of course, although reference is made herein to the Cobra Head style of fixtures, the LED lighting module described is amenable to other similar types of lighting fixtures.

Referring toFIG. 2, a light fixture20including the subject replacement LED light source is depicted. More particularly, a standard roadway light fixture20including a main housing22has been modified to include an LED lighting module24. In this regard, the perimeter of the LED lighting module24is shaped cooperatively to base opening26of the main housing22.

Referring now toFIGS. 3-7, the present disclosure provides a light engine module24including a plurality of LEDs28disposed on a printed circuit board30. The LEDs can emit in combination at least 1500 lumens. Printed circuit boards30are mounted to and in thermal communication with elongated and substantially planar body32. Body32is provided with a plurality of hollow bosses35which receive screws (not shown) that facilitate mounting printed circuit board(s)30to body32. In this manner, through holes between outboard side37of body32and inboard side39can be avoided. Preferably, body32is comprised of a cast metal having a high thermal conductivity to facilitate heat dissipation via spreading throughout the entire roadway lighting fixture20. A plurality of heat dissipating fins34are also provided to enhance heat dissipation by increasing surface area.

Electronics modules36are provided to facilitate the conversion of alternating current to DC current for powering of the LEDs28. The light engine module24is provided with a pair of tabs40which facilitate the attachment to a hinge element on the existing main fixture housing22. Moreover, cooperative tabs or a recess on the main fixture housing22can receive tabs40and be joined together via a post pin or other element.

A clip element44may be provided at end46of the light engine module26to permit selective rotatable mating to light fixture20and retain the module in a closed position. Alternatively, if the original HID fixture includes a clip on the main housing22, it is envisioned that original clip can be utilized to retain the replacement LED module24.

Alternative means for joining the light engine module24to fixture main housing22can include a spring, strap, hinge, hook or other mechanical joinder which allows sufficient rotation to open the LED lighting module.

An optic48is provided on the outboard side37of body32. Optic48overlays the LEDs28and facilitates transmission of a desired light pattern. Optical elements52are additional reflectors that direct light outwardly at a relativity higher orientation to direct light between adjacent poles. If poles are relatively close, the additional light elements52may be unnecessary. Nonetheless it is considered advantageous to provide multiple LED arrays having different focal points to provide light on different targets.

Referring now toFIG. 8, by removing the forward compartment door, the rearward compartment door and the internal HID components and attaching the LED lighting module to the hinge elements used in association with the rearward component door, the bottom section of the lighting fixture20is replaced in its entirety with an LED light module24. This solution is similarly employed when the entire base of the HID light fixture is closed by a single door providing access to the HID lamp and the ballast components.

Advantageously, the present retrofit solution creates a light fixture having excellent heat sinking for LED generated heat as LED lighting module24is a large mass body which is in thermal communication with main fixture housing22. The present LED replacement module can be a complete retrofit module to convert a traditional roadway light fixture from an HID light source to an LED light source by removing the electrics door, the optical door, and associated brackets and replacing them with a complete LED module that fits the existing housing as an integral replacement door. The assembly can be in the form of combined optical door/power door to be separated into two distinct assemblies.

The assembly enables easy field conversion of HID roadway fixtures to LED. By integrating, the LED optical system and power electronics into a single retrofit door assembly, the conversion to LED would be quick, low cost and have good thermal performance.