subject: The present invention provides the following advantages [print this page] The present invention provides the following advantages
The present invention relates to a light emitting diode (LED) unit applied to a fluorescent lighting fixture, and more particularly, to one that replaces a fluorescent tube in comprehensively used fluorescent lighting fixtures and also involves energy and environmental technologies.
A fluorescent tube has been widely used due to its advantages of providing longer service life and less power consumption than an incandescent light does. However, as the energy problem is getting worse today the leakage of mercury from wasted fluorescent light has become another source of pollution to the environment. Therefore, the idea of replacing the fluorescent tube with LED was taught in Japanese Utility Patent Gazette No. Showa 63-121461 (1988), and later in 1994 the feasibility of direct mounting of LED tube in the existing fluorescent lighting fixture was brought up in Japanese Utility Patent Gazette Heisei No. 06-54103. Should the latter be realized, it will do a great contribution to help solve energy and environmental problems. However, putting the feasibility in practice is frustrated by a number of difficulties to be described below.
The primary purpose of the present invention is to provide a light emitting diode (LED) lighting unit to replace the fluorescent tube commonly used in the existing fluorescent lighting fixture.
To achieve the purpose, a source part provided in the LED lighting unit is to rectify the current supplied from a ballast of the fluorescent lighting fixture and to conduct a light emitting diode (LED) assembled unit. The source part comprises a first bridge rectifier, a second bridge rectifier, and a condenser. The LED assembled unit executes the allotment of connection in series and parallel for light emitting diodes to such that the light emitting diodes are capable of corresponding to the source voltage. While connecting the source in parallel to divide the source part into two units, a relay to switch between polarities is mounted to cope with the changed polarity caused by the mounting method used for the lighting fixture.
To realize the replacement with the LED lighting unit, it may be mounted in the existing fluorescent lighting fixture. To achieve this, the LED lighting unit must be capable of emitting light based on the existing foundation. Therefore, to take advantage of the source supplied by the fluorescent lighting fixture to execute LED lighting, it takes further to install a source part in the LED lighting unit to switch current direction. The demanded compact construction of the source part warrants improvement strategy to deal with the heat generated by the circuit becomes a topic for solutions.
Though the LED provides better light emitting results, the loss of light emission will generate heat that brings extremely negative impacts upon the service lives of the LED and other electronic parts. Therefore, the heating must be contained to its minimum.
A first bridge rectifier, a second bridge rectifier, and a condenser provided in the source part of the LED lighting unit are used to rectify the current supplied by the ballast of the existing fluorescent lighting fixture and to conduct the LED assembled unit. The LED assembled unit executes the allotment of the series and parallel connections for the light emitting diodes to cope with the source voltage, and then a resistance is installed in each group of LEDs connected in parallel.
The present invention provides the following advantages: [0018]1. The loss consumed in the course of source conversion and the heating amount generated by the source circuit in the LED tube are controlled to its minimum since the present invention simply rectifies the current supplied by the ballast in the existing fluorescent lighting fixture for realizing direct lighting by the LEDs. [0019]2. In the course of having connected the first bridge rectifier, the second bridge rectifier and the condenser of the source part so to divide them into two units, the method used by the lighting fixture is applied to cope with changed polarity and a relay to switch between polarities is provided to cope with the changed polarity resulted from the LED lighting unit installation method applied for the existing fluorescent lighting fixture. [0020]3. The heat generated inside the tube is permitted to be dissipated to the ambient air while controlling the temperature rise inside the tube since air ventilation pores are disposed on the upper or the lower part of the tube of the LED lighting unit and the heat dissipation efficacy may be further upgraded if an additional air blower is installed inside the LED lighting unit.
