Micron Technology Incorporated

Micron Display Technology, Inc.

Garrett W Hall

David A Zimlich

A transmission line includes a high permeability conductor. The high permeability conductor increases the inductance-per-length of the transmission line to reduce the propagation velocity along the line. The high permeability conductor supplements a high dielectric constant insulator and high permeability core that increase the capacitance-per-length and inductance-per-length, respectively. In one embodiment, the transmission line is a microstrip line that is used in a matrix addressable display. In another embodiment, the transmission line is a coaxial line where the central conductor includes a center layer of nonmagnetic material and an outer layer of high permeability material. The high permeability conductor can be formed from a single layer of high permeability material or may be formed from a central layer of high conductivity material coated with an outer layer of a high permeability conductor.

High permeability tapped transmission line

A transmission line tap for a field emission display includes a driving circuit formed from a charging and clearing circuit and a storage circuit. In one embodiment, the charging and clearing circuit is a single transistor coupled between a supply voltage and the storage circuit. The storage circuit is a single storage capacitor coupled between the transistor and the reference potential. In another embodiment, the charging and clearing circuit is formed from three transistors and an intermediate capacitor, and the storage circuit is formed from a storage capacitor and an output buffer. In either embodiment, pulses of an input voltage selectively charge the storage capacitor to a fixed voltage. The driving circuit then drives a column line of an emitter substrate in response to the storage capacitor. In the first embodiment, the storage capacitor is cleared by pulsing the supply voltage. In the second embodiment, the charging and clearing circuit is self-clearing such that no pulse of the supply voltage is required. Each embodiment is driven by a transmission line using constructively interfered pulses to establish the input voltage.

High impedance transmission line tap circuit

A field emission display includes a discrete storage capacitor coupled between a row line and a reference potential. The display also includes a discharge circuit coupled between a transmission line tap and the storage capacitor. The discharge circuit receives a pulsed image signal from the transmission line and transfers charge from the transmission line to the storage capacitor. In one embodiment, the discharge circuit includes a pair of opposed zener diodes. In response to a brief negative-going input pulse on the transmission line, the capacitor is discharged through the diodes. Then, the diodes recover and capacitor and row line are isolated from the tap. A selected line of an extraction grid is activated to cause an emitter set coupled to the row line to emit electrons. The emitted electrons are replaced by electrons from the capacitor. The capacitor has sufficient capacitance to supply electrons over an expected refresh interval of the row line. Therefore, the voltage of the capacitor remains substantially constant over the refresh interval. Because the capacitor can be charged quickly, the input pulse can be short relative to the refresh interval.

Field emission display having capacitive storage for line driving

A field emission display includes a discrete storage capacitor coupled between a column line and a reference potential. The display also includes a discharge circuit coupled between a transmission line tap and the storage capacitor. The discharge circuit receives an image signal from the transmission line and transfers charge from the transmission line to the storage capacitor. In one embodiment, the discharge circuit includes a pair of opposed zener diodes. In response to a brief negative-going input pulse on the transmission line, the capacitor is discharged through the diodes. Then, the diodes recover and capacitor and column line are isolated from the tap. A selected line of an extraction grid is then activated to extract electrons from an emitter set coupled to the column line. The voltage differential between the extraction grid and the emitter set extracts electrons from the emitter set that are replaced by the capacitor. The capacitor has sufficient capacitance to supply electrons over an expected refresh interval of the column line. Therefore, the voltage of the capacitor remains substantially constant over the refresh interval. Because the capacitor can be charged quickly, the input pulse can be short relative to the refresh interval.

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Boise, ID, United States of America

Garrett W Hall