Layer for reduced charge migration between mems layers
AssigneeQUALCOMM MEMS Technologies, Inc.
InventorsFan Zhong, Guneet Sethi, Daniel Felnhofer, Thanh N. Tu
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Abstract
This disclosure provides systems, methods and apparatus for reducing image artifacts that arise when a display is exposed to sunlight over time. Various implementations disclosed herein can be implemented to prevent charge injection from inducing a negative offset voltage shift for display elements in the display. In one aspect, a buffer layer is applied to block electrons from being photoelectrically ejected from a movable reflective layer of a display element and into a stationary optical stack of the display element.
Claims44
An electromechanical display element having an actuated state and a relaxed state, the electromechanical display element comprising:
- a fixed optical element having a dielectric layer applied over a transparent or semi-transparent conductive layer, and
- a movable reflective element having a reflective conductive layer applied over a buffer dielectric layer;
- wherein a gap is defined by the dielectric layer and the buffer dielectric layer when the electromechanical display element is in the relaxed state, and wherein the buffer dielectric layer is proximate the dielectric layer when the electromechanical display element is in the actuated state, and
- wherein a thickness of the buffer dielectric layer is selected such that, in the actuated state, electrons that are photoelectrically ejected from the reflective conductive layer are substantially prevented from being injected into the dielectric layer.
A method for manufacturing one or more electromechanical display elements having an actuated state and a relaxed state, the method comprising:
- applying a transparent or semi-transparent conductive layer on a base layer;
- applying a dielectric layer over the transparent or semi-transparent conductive layer;
- applying a sacrificial layer over the dielectric layer;
- applying a buffer dielectric layer over the sacrificial layer;
- applying a reflective conductive layer over the buffer dielectric layer;
- and
- removing the sacrificial material to define a gap between the dielectric layer and the buffer dielectric layer, and
- wherein a thickness of the buffer dielectric layer is selected such that, upon actuation to move the buffer dielectric layer to be proximate the dielectric layer, electrons that are photoelectrically ejected from the reflective conductive layer are substantially prevented from being injected into the dielectric layer from the reflective conductive layer.
A display apparatus comprising:
- a plurality of electromechanical display elements, each electromechanical display element having an actuated state and a relaxed state and comprising:
- a movable reflective element;
- and
- a fixed optical element, wherein a gap is defined by the movable reflective element and the fixed optical element when the electromechanical display element is in the relaxed state, and wherein the movable reflective element is proximate the fixed optical element when the electromechanical display element is in the actuated state,
- wherein the movable reflective element includes means for preventing electrons that are photoelectrically ejected from the movable reflective element from being injected into the fixed optical element when the electromechanical display element is in the actuated state.
Dependencies are inferred from the claim text.