Analog data shifter for a current mode display
AssigneeFacebook Technologies, LLC
InventorsWilliam Thomas Blank, Ilias Pappas
Life of this patent
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Abstract
Techniques are described for operating a display comprising an array of emitters arranged in at least one column. Data is shifted through the emitters of the column using a data shifting circuit. The data can be shifted sequentially, one emitter at a time. The data shifting circuit includes storage elements for temporary storage of the data as it is shifted down the column. The data can be stored as a charge on a capacitor, where the capacitor is charged to a particular voltage according to a current from a current mirror. The shifting can be performed in synchronization with scanning of the emitters by a scanning assembly, where the scanning produces an output image for viewing by a user.
Claims20
A display system, comprising:
- an emitter array including a plurality of emitters arranged in a column;
- and
- a data shifting circuit including a first storage element and a second storage element, wherein the data shifting circuit is configured to:
- cause a first drive signal to be applied to a first emitter in the column, wherein the first drive signal produces current that determines an extent to which the first emitter is activated;
- while the first drive signal is being applied to the first emitter, store a charge in the first storage element, the charge being sufficient to reproduce the current produced by the first drive signal;
- after the first emitter has been activated, transfer the charge from the first storage element to the second storage element;
- generate a second drive signal using the charge in the second storage element;
- and
- cause the second drive signal to be applied to a second emitter in the column.
A display system, comprising:
- an emitter array including a plurality of emitters arranged in a column;
- a scanning assembly configured to generate an output image by scanning the plurality of emitters;
- a display driver configured to generate data values for driving the plurality of emitters in synchronization with scanning of the plurality of emitters by the scanning assembly;
- and
- a data shifting circuit including a first storage element and a second storage element, wherein the data shifting circuit is configured to:
- receive, from the display driver, data for a first emitter in the column;
- cause a first drive signal to be applied to the first emitter during scanning by the scanning assembly, wherein the first drive signal produces current that activates the first emitter according to the data for the first emitter;
- while the first drive signal is being applied to the first emitter, store a charge in the first storage element, the charge being sufficient to reproduce the current produced by the first drive signal;
- after the first emitter has been activated, transfer the charge from the first storage element to the second storage element;
- generate a second drive signal using the charge in the second storage element;
- and
- cause the second drive signal to be applied to a second emitter in the column.
A data shifting circuit, comprising:
- multiple instances of an emitter cell, wherein the emitter cells are connected in a chain, each emitter cell being configured to perform the following for a respective emitter driven by the emitter cell:
- receive a first charge for the emitter;
- activate the emitter, wherein to activate the emitter, the emitter cell is configured to generate a first drive signal using the first charge and apply the first drive signal to the emitter, wherein the first drive signal produces current that determines an extent to which the emitter is activated;
- while the first drive signal is being applied to the emitter, store a second charge in a storage element of the emitter cell, the second charge being sufficient to reproduce the current produced by the first drive signal;
- and
- except for a last emitter cell in the chain, transfer the second charge from the storage element of the emitter cell as the first charge received by a next emitter cell in the chain.
Dependencies are inferred from the claim text.