UV LED radiation sources for use in photopolymer exposure

A retrofit exposure system for retrofitting a bank light exposure unit configured for use with fluorescent tubes configured to emit actinic radiation, each of the fluorescent tubes having a specified length and a first set of electrical connectors in a first configuration configured to mate with a second set of electrical connectors of the bank light exposure unit having a second configuration and connected to a power supply, the bank light exposure unit including a substrate having a first surface for receiving a photopolymer printing plate, the retrofit exposure system comprising:

• a photopolymer printing plate disposed on the first surface of the substrate and defining a target illumination plane on a top side of the photopolymer printing plate;
• a plurality of radiation sources spaced from the first surface of the substrate, each radiation source configured to emit actinic radiation directed only toward the target illumination plane, the actinic radiation operative for curing the photopolymer printing plate printing plate each radiation source comprising:
• a base having a width and a length along an axis, wherein the length is greater than the width, the base comprising a front portion facing the target illumination plane and an underside portion facing away from the target illumination plane, the front portion comprising a singular rectangular planar mounting surface disposed parallel to the target illumination plane and having a length and a width facing the target illumination plane, the underside portion comprising a metal heat sink;
• one or more circuit boards mounted on the mounting surface of the base, the one or more circuit boards collectively comprising a plurality of light emitting diodes (LEDs) each having an ultraviolet center emission wavelength, the plurality of LEDs distributed over the length of the base in an array, the array defining a plurality of LEDs across the length of the LED mounting surface and a plurality of LEDs across the width of the LED mounting surface, all facing the target illumination plane, the plurality of LEDs across the width of the LED mounting surface configured to provide the actinic radiation at an emission angle greater than an emission angle of a single LED in a first plane perpendicular to the axis of the base, greater than an emission angle of a single LED in a second plane containing the axis of the base or parallel to the axis of the base and perpendicular to the target illumination plane, or a combination thereof;
• one or more first controllers disposed in the radiation source for regulating power delivered to the plurality of LEDs, each first controller configured to maintain a desired current through the plurality of LEDs;
• a plurality of radiation source electrical connectors configured to interface with the second set of electrical connectors;
• and
• a cover transparent or translucent to the actinic radiation and mounted on the base, the cover together with the base defining an enclosure for the plurality of LEDs.