Cold cathode fluorescent lamp, cold cathode fluorescent lamp driving apparatus, cold cathode fluorescent lamp apparatus, liquid crystal display apparatus, control method for cold cathode fluorescent lamp, and control method for liquid crystal display apparatus

A cold cathode fluorescent lamp apparatus, comprising:

• a cold cathode fluorescent lamp including an optically transparent sealed vessel containing a gas and having a fluorescent material disposed on an inner surface thereof, the gas emitting light when electrons collide therewith, and the fluorescent material reacting with the light, first and second internal electrodes disposed inside the sealed vessel and formed at least partially from an electron emitting material, and first and second external electrodes disposed in a spaced relationship from each other on an outer surface of the sealed vessel;
• a dc driving circuit operable to apply a dc voltage between the first and second internal electrodes of the cold cathode fluorescent lamp;
• a constant current circuit operable to provide a predetermined dc current flow between the first and second internal electrodes of the cold cathode fluorescent lamp;
• an ac driving circuit operable to apply an ac voltage between the first and second external electrodes of the cold cathode fluorescent lamp;
• and
• a changeover circuit operable to control the dc driving circuit and the ac driving circuit such that the ac voltage is applied for a predetermined period of time to cause the electrons and the gas to collide with each other and the dc voltage is applied while the collisions between the electrons and the gas continue.

A liquid crystal display apparatus, comprising:

• a liquid crystal display panel operable to display an image according to an image signal at a position thereof according to a synchronizing signal;
• and
• a cold cathode fluorescent lamp apparatus disposed on a rear side of the liquid crystal display panel;
• the cold cathode fluorescent lamp apparatus including:
• a cold cathode fluorescent lamp including an optically transparent sealed vessel containing a gas and having a fluorescent material disposed on an inner surface thereof, the gas emitting light when electrons collide therewith, and the fluorescent material reacting with the light, first and second internal electrodes disposed inside the sealed vessel and formed at least partially from an electron emitting material, and first and second external electrodes disposed in a spaced relationship from each other on an outer surface of the sealed vessel;
• a dc driving circuit operable to apply a dc voltage between the first and second internal electrodes of the cold cathode fluorescent lamp;
• a constant current circuit operable to provide a predetermined dc current flow between the first and second internal electrodes of the cold cathode fluorescent lamp;
• an ac driving circuit operable to apply an ac voltage between the first and second external electrodes of the cold cathode fluorescent lamp;
• and
• a changeover circuit operable to control the dc driving circuit and the ac driving circuit such that the ac voltage is applied for a predetermined period of time according to the synchronizing signal to cause the electrons and the gas to collide with each other and the dc voltage is applied while the collisions between the electrons and the gas continue to control the polarity direction and the passage and blocking of the dc current flow in the cold cathode fluorescent lamp.

A cold cathode fluorescent lamp apparatus, comprising:

• a cold cathode fluorescent lamp including an optically transparent sealed vessel containing a gas and having a fluorescent material disposed on an inner surface thereof, the gas emitting light when electrons collide therewith, and the fluorescent material reacting with the light, and first and second internal electrodes disposed inside the sealed vessel and formed at least partially from an electron emitting material;
• a dc driving circuit operable to apply a dc voltage between the first and second internal electrodes of the cold cathode fluorescent lamp;
• an ac driving circuit operable to apply an ac voltage between the first and second internal electrodes of the cold cathode fluorescent lamp;
• a current direction control and constant current circuit operable to provide a predetermined dc current flow between the first and second internal electrodes of the cold cathode fluorescent lamp;
• and
• a changeover circuit operable to control the dc driving circuit and the ac driving circuit such that the ac voltage is applied for a predetermined period of time to cause the electrons and the gas to collide with each other and the dc voltage is applied while the collisions between the electrons and the gas continue to control the polarity direction and the passage and blocking of the dc current flow in the cold cathode fluorescent lamp.