Image display apparatus
View Patent ↗There is provided an image display apparatus having light emitting elements in its pixels, and capable of producing a high-resolution, multi-gray-scale-level display. In an embodiment of the present invention, each of pixel circuits is provided with a current limiting circuit for generating a specified drive current and a time modulation circuit for modulating a duration of time supplying the specified drive current to the light emitting element. In another embodiment of the present invention, each of pixel circuits is provided with a current limiting circuit for generating a specified drive current and a current generator circuit for generating a plurality of values of currents on the basis of the specified drive current.
1. An image display apparatus, comprising:
a plurality of pixels disposed on a substrate;
a plurality of signal lines for inputting display signals into said plurality of pixels; and
a plurality of signal lines for inputting control signals into said plurality of pixels;
wherein said plurality of signal lines for inputting display signals into said plurality of pixels and said plurality of signal lines for inputting control signals into said plurality of pixels are arranged in a matrix configuraton;
wherein each of said plurality of pixels is provided with a light emitting element with light intensity thereof varying with a current therethrough, and a pixel circuit for driving said light emitting element;
wherein said pixel circuit is provided with current limiting means for generating a specified drive current, and a time modulator circuit for modulating a duration of time supplying said specified drive current to said light emitting element;
wherein said image display apparatus further comprises a reference-current source disposed outside of said pixel circuit for generating a reference current, said current limiting means is provided with storage means for storing information on a value of said reference current, said current limiting means is formed of at least one thin film transistor, said storage means is formed of a capacitor, and said capacitor stores a gate voltage of said at least one thin film transistor when said reference current flows through said at least one thin film transistor; and
wherein said time modulator circuit is supplied with a triangular sweep voltage, and is configured to reset said gate voltage stored in said capacitor when said triangular sweep voltage becomes equal to an analog voltage signal stored in advance which is said display signal.
2. An image display apparatus according to claim 1 , wherein said pixel circuit is formed of thin film transistors.
3. An image display apparatus according to claim 1 , wherein said pixel circuit is formed of thin film transistors of only one of n-channel and p-channel types.
4. An image display apparatus according to claim 1 , wherein said reference-current source formed of thin film transistors fabricated on said substrate.