Systems and methods for providing a heaterless hollow cathode for use in electric propulsion devices is presented. According to one aspect the cathode includes a thermionic emitter having a constricted upstream inlet compared to a downstream outlet of the emitter. The emitter is arranged downstream a hollow cathode tube. Constriction of the upstream inlet is provided by an inner cylindrical hollow space at an upstream region of the emitter having a diameter that is smaller compared to a diameter of an inner cylindrical hollow space at a downstream region of the emitter. A hollow transition region having a varying diameter connects the upstream region to the downstream region. According to another aspect, a ratio of the diameters of the two cylindrical hollow spaces reduces penetration of electric field, and therefore of electric discharge, into the upstream region of the emitter during operation.

An electron tube includes a housing that is internally held in a vacuum and has a window transmitting an electromagnetic wave, an electron emitting unit that is disposed in the housing and has a meta-surface emitting electrons in response to incidence of the electromagnetic wave, an electron multiplying unit that is disposed in the housing and multiplies the electrons emitted from the electron emitting unit, and an electron collecting unit that is disposed in the housing and collects the electrons multiplied by the electron multiplying unit. The window contains at least one selected from quartz, silicon, germanium, sapphire, zinc selenide, zinc sulfide, magnesium fluoride, lithium fluoride, barium fluoride, calcium fluoride, magnesium oxide, and calcium carbonate.

An image sensor has a photocathode window assembly, an anode assembly, and a malleable metal seal. The photocathode window assembly has a photocathode layer. The anode assembly includes a silicon substrate that has an electron sensitive surface. The malleable metal seal bonds the photocathode window assembly and the silicon substrate to each other. A vacuum gap separates the photocathode layer from the electron sensitive surface. A first electrical connection and a second electrical connection are for a voltage bias of the photocathode layer relative to the electron sensitive surface.

Example compact modular electron beam units are provided that can be used to generate electron beams using field emitter elements. A modular electron beam unit may comprise an electron beam source including a base portion, at least one field emitter element coupled to the base portion, the field emitter element including a field emitter tip, at least one gate electrode and a membrane window disposed over the at least one gate electrode.

Example compact modular electron beam units are provided that can be used to generate electron beams using field emitter elements. A modular electron beam unit may comprise an electron beam source including a base portion, at least one field emitter element coupled to the base portion, the field emitter element including a field emitter tip, at least one gate electrode and a membrane window disposed over the at least one gate electrode.

A method and product produced by the method for forming an interactive information device with a conductively coated panel includes forming a reduced contrast increased light transmitting, conductively coated panel by providing a transparent substrate and applying a transparent, conductive layer on at least one surface of the substrate in a predetermined pattern with at least one area having a conductive layer thereon and a second area without a conductive layer. The method further includes applying a transparent layer of a metal oxide such that the metal oxide layer, such as silicon dioxide, overlies both areas whereby visible contrast between the areas is reduced and light transmission through the coated panel is increased. The coated panel is then attached to an electro-optic display for displaying information when electricity is applied thereto.

An image sensor has a photocathode window assembly, an anode assembly, and a malleable metal seal. The photocathode window assembly has a photocathode layer. The anode assembly includes a silicon substrate that has an electron sensitive surface. The malleable metal seal bonds the photocathode window assembly and the silicon substrate to each other. A vacuum gap separates the photocathode layer from the electron sensitive surface. A first electrical connection and a second electrical connection are for a voltage bias of the photocathode layer relative to the electron sensitive surface.

Systems and methods for providing a heaterless hollow cathode for use in electric propulsion devices is presented. According to one aspect the cathode includes a thermionic emitter having a constricted upstream inlet compared to a downstream outlet of the emitter. The emitter is arranged downstream a hollow cathode tube. Constriction of the upstream inlet is provided by an inner cylindrical hollow space at an upstream region of the emitter having a diameter that is smaller compared to a diameter of an inner cylindrical hollow space at a downstream region of the emitter. A hollow transition region having a varying diameter connects the upstream region to the downstream region. According to another aspect, a ratio of the diameters of the two cylindrical hollow spaces reduces penetration of electric field, and therefore of electric discharge, into the upstream region of the emitter during operation.

According to some aspects, a cold cathode device is provided, the device comprising a substrate, a field electron emitter disposed upon the substrate and configured to emit electrons in a first direction, and a structure encapsulating the field electron emitter, thereby creating an airtight seal around the field electron emitter, at least a portion of the structure being an atomically thin membrane positioned in the first direction with respect to the field electron emitter. According to some embodiments, at least one einzel lens may be located within the structure and configured to direct electrons emitted by the field electron emitter.

According to some aspects, a cold cathode device is provided, the device comprising a substrate, a field electron emitter disposed upon the substrate and configured to emit electrons in a first direction, and a structure encapsulating the field electron emitter, thereby creating an airtight seal around the field electron emitter, at least a portion of the structure being an atomically thin membrane positioned in the first direction with respect to the field electron emitter. According to some embodiments, at least one einzel lens may be located within the structure and configured to direct electrons emitted by the field electron emitter.