| 摘要 |
PROBLEM TO BE SOLVED: To significantly improve a starting characteristic, and attain thinning and weight reduction of a back light unit by adopting a structure that discharge light emission is easily generated in a light emitting tube by carrying an electron emitting substance on a phosphor layer or a phosphor layer surface corresponding to a sealed cold cathode part. SOLUTION: In a glass tube 5 of a cold cathode low pressure discharge lamp, a phosphor layer 6 to emit the light by a stimulus by ultraviolet rays is arranged on an inner wall surface, and noble gas is also sealed. Cold cathodes 7 and 7' are respectively installed in tip parts of a pair of lead-in wires 8 and 8' respectively sealed in both end parts of the glass tube 5. An electron emitting substance layer 9 having a thickness of about 1 to 2μm is arranged on an area surface where the phosphor layer 6 surrounds the cold cathodes 7 and 7'. In this way, the electron emitting substance layer 9 is formed and carried on a prescribed area surface of the phosphor layer 6, even in a dark atmosphere, it is put in a condition of easily generating discharge in the initial stage of current-carrying, and steady discharge and light emission can be reached in a short time.
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