Field Emission Device Electron Emitter Placement
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Solution Overview
Problem
Conventional field emission displays, particularly triode type structures, face challenges in achieving high resolution due to divergent electron emission, low efficiency, and the need for high voltages, which result in space resolution failures and inefficient electron transfer.
Innovation Solution
The field emission device incorporates a unique configuration with electron emitters distributed on the cathode electrode adjacent to two sides of the gate electrode, allowing electrons to be guided without impinging on the gate, thereby improving electron emission efficiency and focusing them precisely onto a phosphor layer using a suspended central-gated structure with narrow gate wires and radially arranged emitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional triode type structures are used, then electron emission can be controlled, but electrons diverge and fail to reach the correct phosphor unit, causing space resolution failure
Solution Approach 1:
The patent positions electron emitters on the lateral surfaces of the cathode electrode adjacent to the gate electrode, rather than only at the bottom. This spatial rearrangement in multiple dimensions allows electrons to be emitted from positions that are guided by the gate electrode's electric field, preventing divergence and ensuring electrons reach the correct phosphor unit, thereby resolving the space resolution issue.
2Power
If high voltage is applied to achieve electron emission, then electrons can be emitted, but electron transfer efficiency decreases and energy consumption increases
Solution Approach 1:
The patent creates a localized strong electric field region by positioning the gate electrode close to the cathode electrode surface where electron emitters are located. This localized field configuration enables efficient electron emission and transfer at lower voltages, improving electron transfer efficiency while reducing energy consumption compared to conventional high-voltage approaches.
3Ease of manufacture
If electron emitters are positioned at the bottom of gate holes, then structure is simple, but electrons diverge and impinge on the gate electrode, reducing emission efficiency
Solution Approach 1:
The patent distributes electron emitters on the lateral surfaces of the cathode electrode adjacent to the gate electrode, utilizing the side surfaces in addition to the bottom surface. This multi-dimensional positioning allows electrons to be emitted from positions that are naturally guided by the gate electrode's electric field, preventing impingement on the gate and improving emission efficiency while maintaining manufacturing simplicity.
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
This configuration enhances electron emission efficiency, reduces the required voltage, and achieves higher resolution and better display quality by minimizing the light spot on the phosphor layer, addressing the limitations of conventional triode type structures.
Implementation Method 1
In use, different voltages are applied to the emitter 105, the anode electrode 106 and the gate electrode 103. For example, about 5.1 kilovolts is applied to the anode electrode 106 and the fluorescent layer 107, about 7.0 volts is applied to the emitter 105, and about 100 volts is applied to the gate electrode 103. Thereby, equipotential surfaces (not labeled) are formed.
Implementation Method 2
Carbon nanotubes can have an extremely high electrical conductivity, very small diameters (much less than 100 nanometers), large aspect ratios (i.e. length/diameter ratios) (potentially greater than 1000), and a tip-surface area near the theoretical limit (the smaller the tip-surface area, the more concentrated the electric field, and the greater the field enhancement factor). Thus, carbon nanotubes can transmit an extremely high electrical current and have a very low turn-on electric field (approximately 2 volts/micron) for emitting electrons.
Data Source
AI summary
A field emission device (10), in accordance with a preferred embodiment, includes an anode electrode (22), a cathode electrode (12), a gate electrode (16), a phosphor layer (23), and a number of electron emitters (13) formed on the cathode electrode. The anode electrode is opposite to and spaced from the cathode electrode. The phosphor layer is attached/formed on the anode electrode. The gate electrode (preferably in the form of a wire) is spatially positioned between the anode electrode and the cathode electrode. In addition, the gate electrode is correspondingly arranged relative to the phosphor layer. The electron emitters are distributed on surfaces of the cathode electrode at least adjacent to two sides of the gate electrode, thus promoting the ability of the emitted electrons to be guided by, yet not readily impinge on, the gate electrode on a path toward the phosphor layer.