Lateral Field Emission Device Structure for Uniform Brightness
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Solution Overview
Problem
Conventional field emission displays face challenges in manufacturing due to the need for precise spacers, uneven brightness, sensitivity of electron beams to distance, and high costs associated with indium tin oxide glass and complex manufacturing processes, particularly when scaling to large-area displays.
Innovation Solution
A horizontal field emission device structure where electrons penetrate independently distributed fluorescent powder, eliminating the need for expensive ITO glass and precise spacers, with a substrate, pixels, and a glass substrate forming a vacuum space to enhance manufacturing efficiency and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a vertical field emission structure is used with spacers to control distance, then the device structure is established, but the manufacturing precision and cost increase significantly
Solution Approach 1:
The patent inverts the conventional vertical field emission structure to a horizontal configuration. Instead of positioning the cathode and anode vertically with spacers, the cathode is positioned horizontally beneath the fluorescent powder layer and the anode is positioned horizontally above it, eliminating the need for precision spacers and simplifying the overall device structure.
Solution Approach 2:
The patent removes the spacer component entirely from the device structure. By adopting a horizontal configuration where the cathode and anode are positioned on opposite sides of the fluorescent powder layer, the device eliminates the need for spacers that are required in vertical structures to maintain precise distances.
2Illumination intensity
If ITO glass is used for the anode to allow light transmission, then light can pass through, but the manufacturing cost increases
Solution Approach 1:
The patent inverts the conventional arrangement where the anode is positioned below the fluorescent powder. Instead, the anode is positioned horizontally above the fluorescent powder layer, allowing light to emit upward through the device structure without requiring expensive light-transmissive ITO glass for the anode.
Solution Approach 2:
The patent replaces expensive ITO glass with a conventional non-transmissive anode material positioned above the fluorescent powder. This substitution significantly reduces manufacturing costs while maintaining the light emission function, as the light travels upward rather than requiring the anode itself to be transparent.
3Power
If the gate is positioned close to the cathode to increase electron emissivity, then electron emission improves, but the brightness uniformity deteriorates
Solution Approach 1:
The patent eliminates the gate structure entirely by inverting to a horizontal field emission configuration. The horizontal positioning of the cathode and anode on opposite sides of the fluorescent powder layer creates a more uniform electric field distribution, removing the need for the gate and its associated precision distance control requirements.
4Ease of manufacture
If a horizontal field emission structure is used, then manufacturing cost and complexity are reduced, but the electron penetration efficiency must be maintained
Solution Approach 1:
The patent inverts the field emission configuration from vertical to horizontal, with the cathode positioned horizontally beneath the fluorescent powder layer and the anode positioned horizontally above it. This inversion enables electrons to be emitted from the cathode and penetrate the fluorescent powder layer horizontally, maintaining penetration efficiency while simplifying manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The horizontal structure allows for uniform brightness, reduced manufacturing costs, and increased luminescence efficiency, producing a larger linear light source with improved contrast and reduced dark spots, while enabling precise control of the cathode-anode distance at a lower cost.
Implementation Method 1
field-emission electrons are emitted from the field emitter 21 of the cathode 20 in a vacuum space to impact the fluorescent powder 11 on the anode 10 for the fluorescent powder 11 to produce light
Implementation Method 2
the fluorescent powder 11 to produce light
Implementation Method 3
The gate 22 is connected to a relatively small positive electricity, so as to attract the cathode to increase the electron emissivity
Implementation Method 4
attract the cathode to increase the electron emissivity
Implementation Method 5
a vacuum space is formed between the glass substrate and the substrate to enclose the pixels therein
Data Source
AI summary
A field emission device has pixels with cathode and anode provided on the same plane, so that electrons directly penetrate an independently provided fluorescent powder layer to produce light, giving the display the advantages of easy focusing, no dark spots, high brightness, and enhanced light emitting performance. Since the light produced by the fluorescent powder layer is not blocked by the anode, the problem of charge accumulation on the fluorescent powder layer is avoided, and it is not necessary to use expensive light-transmittable conducting glass as the anode. With the cathode and the anode located at the same plane, it is not necessary to use a high precision spacer to maintain a fixed distance between the cathode and the anode, enabling the device to be manufactured at reduced cost and high good yield.