Sintered electrode for cold cathode tube, and cold cathode tube and liquid crystal display device using the sintered electrode
This invention provides a sintered electrode for a cold cathode tube in a cylindrical form having a bottom part on one end and an opening part on the other end, characterized in that a lead-in wire is joined integrally to the bottom part and a requirement of d 2 /d 1> 1 is satisfied wherein d 1 represents the density of the sintered electrode; and d 2 represents the density of the lead-in wire. According to the sintered electrode for a cold cathode tube, the bonding strength between the sintered electrode and the lead-in wire is high, and the handleability is good. The main component of the sintered electrode is particularly preferably identical to the main component of the lead-in wire. Enhancing the density of the lead-in wire can contribute to a further improvement, for example, in reliability.
1. A sintered electrode for a cold cathode tube in a cylindrical form having a bottom part on one end and an opening part on the other end, wherein a lead-in wire is joined integrally to the bottom part; and
wherein a requirement of d 2 /d 1 >1 is satisfied, wherein d 1 represents a density of the sintered electrode and is in a range of 90% to 96%, and d 2 represents a density of the lead-in wire and is in a range of 92% to 100%; and
wherein a joint interface between the sintered electrode and the lead-in wire is a sintered bond.
2. The sintered electrode for a cold cathode tube according to claim 1 , wherein a main component of the sintered electrode is identical to the main component of the lead-in wire.
3. The sintered electrode for a cold cathode tube according to claim 1 , wherein the sintered electrode is composed mainly of at least one material selected from tungsten, molybdenum, niobium, tantalum, rhenium, and nickel.
4. The sintered electrode for a cold cathode tube according to claim 1 , wherein an inner face of the sintered electrode has a surface roughness (Sm) of not more than 100 μm.
5. A cold cathode tube comprising:
a hollow tubular light transparent bulb having a discharge medium sealed therein;
a phosphor layer provided on an inner wall face of the tubular light transparent bulb; and
a pair of sintered electrodes for a cold cathode tube according to claim 1 provided at both ends of the tubular light transparent bulb.
6. A liquid crystal display device comprising:
a cold cathode tube according to claim 5 ;
a light guide body disposed in proximity to the cold cathode tube;
a reflector disposed on one side of the light guide body; and
a liquid crystal display panel disposed on another side of the light guide body.
7. The sintered electrode for a cold cathode tube according to claim 1 , wherein a front end of the lead-in wire does not extend through a bottom part of the sintered electrode.