US 5,748,160 AGranted

Active driven LED matrices

AssigneeMororola, Inc.

InventorsChan-Long Shieh, Hsing-Chung Lee, Franky So

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Abstract

A matrix of light emitting devices including a voltage source constructed to repetitiously supply a multi-step voltage waveform and a matrix of rows and columns of pixels, each pixel being connected to the voltage source. A method of driving the matrix including addressing each of the pixels of the matrix by supplying scan and image data activating signals to each of the pixels, the image data activating signal being used to activate a pixel by completing a current path from the pixel to a return for the voltage source, and activating the voltage source to repetitiously supply multi-step waveforms of voltage and sequentially supply each step of each of the multi-step voltage waveforms to the pixels, and addressing each of the pixels in the matrix for each step supplied.

Claims17

Dependent claims

Active drive apparatus for a matrix of light emitting devices comprising:

a voltage source constructed to repetitiously supply a multi-step voltage waveform when activated;
a matrix including a plurality of rows of light emitting devices and a plurality of columns of light emitting devices, each light emitting device having a first contact connected to the voltage source and a second contact;
a plurality of semiconductor switches, one each associated with each light emitting device, each semiconductor switch having a first current carrying terminal connected to the second contact of the associated light emitting device and a second current carrying terminal connected to a common terminal, each semiconductor switch further having first and second activating input terminals, and each semiconductor switch being constructed to complete a circuit between the first and second current carrying terminals only when activating signals are supplied to both of the first and second activating input terminals;
and
a column driver circuit having a plurality of column outputs one each associated with each column of light emitting devices, all of the first activating terminals of each semiconductor switch associated with the light emitting devices in each specific column of light emitting devices being connected together and to the associated column output of the plurality of column outputs;
a row driver circuit having an output all of the second activating terminals of each semiconductor switch associated with the light emitting devices in each specific row of light emitting devices being connected together and to the output of the row driver circuit:
timing circuitry connected to the voltage source, the column driver circuit and the row driver circuit, the timing circuit being constructed to control the row driver circuit to provide an activating signal to each row in sequence and to control the column driver circuit to provide an activating signal to each column for each activating signal applied to a row, each activation or addressing of all of the light emitting devices in the matrix being a sub-frame;
and
the timing circuit being further constructed to control the column and row driver circuits and the voltage source and to supply a next sequential step of the multi-step voltage waveform each time a sub-frame is completed, a frame being completed when all of the multi-step voltages of the waveform are supplied.

6 more elements

Active drive apparatus for a matrix of light emitting devices comprising:

a voltage source having a plurality of outputs and constructed to repetitiously supply a multi-step voltage waveform sequentially on each of the outputs when activated;
a matrix including a plurality of rows of pixels and a plurality of columns of pixels, each pixel including a plurality of light emitting devices with a first light emitting device of the plurality of light emitting devices having a first contact connected to a first output of the plurality of outputs of the voltage source and a second light emitting device of the plurality of light emitting devices having a first contact connected to a second output of the plurality of outputs of the voltage source, and the first and second light emitting devices of each pixel each having a second contact;
and
a plurality of semiconductor switches, one each associated with each pixel, each semiconductor switch having a first current carrying terminal connected to the second contacts of each of the first and second light emitting devices of the associated pixel and a second current carrying terminal connected to a common terminal, each semiconductor switch further having first and second activating input terminals, and each semiconductor switch being constructed to complete a circuit between the first and second current carrying terminals only when activating signals are supplied to both of the first and second activating input terminals.

1 more element

Dependencies are inferred from the claim text.