This cathode (also known as a dispenser cathode) is available in a modular construction . It is used in many types of cathode ray tubes (CRT) including high end colour picture tubes (CPT), projection TV (PTV) and in CRT for medical and military applications. It has a high specification and delivers high electron beam currents which do not decrease over life.

It has the following key features:

• Allows a very small spot size (with high resolution) for wide-screen, real flat colour picture tube and projection TV applications. It can handle much higher current densities than conventional oxide cathodes.  This allows for narrower electron beams
• Extremely stable emission characteristics and longer lifetimes with no decrease in emission performance over life (>20,000 hours at present day cathode loadings)
• Fast warm up time because of the suspended cathode structure giving excellent thermal stability
• Low power consumption (0.65 W) with advanced design
• Improved quality control and production yield because of the modular structure incorporating an integrated heater which allows simple mounting into an electron gun

Performance Application of Impregnated Cathode

The Cathode Module is a suspended cathode with an integral heater.

The suspended construction offers several advantages:

• Low power
• Fast switch on
• Good thermal stability and low white balance drift

Lifetime Performance

This graph shows that the I-Cathode shows no decrease in emission current over 20,000hrs, unlike the oxide cathode.