Field emission display having circuit for preventing emission to grid

A field emission display comprising:

• a plurality of emitter sites configured for electron emission;
• a display screen configured to receive the electron emission to form a visual image;
• a grid for controlling the electron emission;
• a focus ring for focusing the electrons onto the display screen;
• and
• a control circuit configured to sense a voltage at the display screen and to enable the focus ring provided the voltage is above a threshold voltage.

A method for controlling a field emission display comprising:

• providing a plurality of emitter sites, a grid for controlling electron emission from the emitter sites, and a display screen for receiving the electron emission to form a visual image;
• providing a control circuit comprising a first grid bias path having a first impedance selected to prevent the electron emission, and a second grid bias path selected to allow the electron emission;
• sensing a voltage at the display screen;
• enabling the grid using the first grid bias path when the voltage is above a threshold voltage;
• and
• preventing the electron emission using the second grid bias path when the voltage is below the threshold voltage.

A method for controlling a field emission display comprising:

• providing a plurality of emitter sites configured for electron emission;
• providing a display screen configured to receive the electron emission to form a visual image;
• providing a grid configured to control the electron emission;
• detecting a voltage at the display screen;
• and
• delaying enabling of the grid until a threshold voltage is detected at the display screen.

A method for controlling a field emission display comprising:

• providing a plurality of emitter sites, a focus ring for focusing the electron emission, and a display screen for receiving the electron emission to form a visual image;
• sensing a voltage at the display screen;
• enabling the focus ring to provide the electron emission when the voltage is above a threshold voltage;
• and
• preventing the electron emission by not enabling the focus ring when the voltage is below the threshold voltage.