US 5,210,472 A · Flat panel display in which low-voltage row and column address signals control a much pixel activation voltage

Abstract

A flat panel display in which low-voltage row and column address signals control a much higher pixel activation voltage. Although the invention was created with field-emission displays in mind, the technique may be used in any matrix-addressable display (e.g. vacuum fluorescent, electro-luminescent, or plasma-type displays) where high pixel activation voltages must be switched. In a preferred embodiment field emission display, emitter-to-grid voltage differential is maintained near zero during non-emission periods, and is raised to a level sufficient to cause emission by grounding pixel emitters at each row and column intersection through a pair of series-connected field-effect transistors (FETs). The emitter base electrode of each emitter node is coupled to the grid via a current-limiting transistor. Display brightness control is accomplished by varying the gate voltages of either FET, such that emission current can be adjusted. In addition, a fusible link is placed in series with the grounding path through the series-connected FETs. Gray scale shading is accompanied by varying the duty cycle of pixel actuation time as a percentage of frame time.

Claims24

Dependent claims

A field emission display comprising:

multiple row address lines;
multiple column address lines;
said row address lines intersecting said column address lines, with the intersection of a single row address line with a single column address line being associated with a single pixel within said display;
a grid which is common to the entire display, and which is continuously held at a first potential;
groups of field emission cathodes, each group being associated with a particular pixel, each group being maintained at a second potential during periods of pixel inactivation through at least one current-limited, grid-to-emitter conductive path per pixel, said second potential being close enough to said first potential so as to suppress field emission, and each group being maintained at some other potential during periods of pixel activation, said other potential being sufficiently low, with respect to said first potential, to induce field emission;
means, responsive to signals on a pixel's associated row address line and column address line, for switching the potential on the group of cathodes associated with that pixel between said second potential and said other potential.

3 more elements

A field emission display comprising:

multiple row address lines;
multiple column address lines;
said row address lines intersecting said column address lines, with the intersection of a single row address line with a single column address line being associated with a single pixel within said display;
a grid which is common to the entire display, and which is continuously held at a first potential;
groups of field emission cathodes, each group being associated with a particular pixel, each group being maintained at a second potential during periods of pixel inactivation, said second potential being close enough to said first potential so as to suppress field emission, and each group being maintained at some other potential during periods of pixel activation, said other potential being sufficiently low, with respect to said first potential, to induce field emission;
at least one pull-down current path between the cathode group of each pixel and said other potential, said path being activatable in response to signals on a pixel's respective row address line and column address line, so as to enable switching of the potential applied to the cathode group associated with that pixel between said second potential and said other potential.

3 more elements

Dependencies are inferred from the claim text.

Flat panel display in which low-voltage row and column address signals control a much pixel activation voltage

Life of this patent

Flat panel display in which low-voltage row and column address signals control a much pixel activation voltage

Life of this patent

Abstract

Claims24