Translucent Storage Capacitor in Liquid Crystal Pixel Aperture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In liquid crystal devices, increasing the number of pixels without increasing the device size poses challenges in making transistors compact and securing storage capacitors with predetermined electrical capacitance, while translucent storage capacitors in aperture regions can lead to reduced light transmittance due to absorption and reflection in thin film layers.
Innovation Solution
An electro-optical device with a translucent pixel electrode and a storage capacitor having a pair of translucent electrodes facing each other through a dielectric layer, along with an interlayer insulator film, where the film thicknesses of the pixel electrode, translucent electrodes, and interlayer insulator are optimized to achieve peak transmittance across visible light wavelengths, using ITO films and silicon dioxide layers to ensure high transmittance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased without changing the device size, then pixel definition is improved, but the area available for transistors and storage capacitors is reduced
Solution Approach 1:
The storage capacitor is moved from the non-aperture region to the aperture region, utilizing the vertical stacking dimension to place the capacitor above the transistor in the aperture area. This allows high-definition pixels with sufficient space for both transistors and storage capacitors by transitioning from a planar layout to a three-dimensional structure.
Solution Approach 2:
The storage capacitor is nested within the aperture region by stacking it vertically above the transistor element. The capacitor occupies the same footprint area as the transistor in the planar view, but extends in the vertical dimension, effectively nesting the capacitor within the existing pixel structure without increasing the pixel area.
2Quantity of substance
If a translucent storage capacitor is provided in the aperture region, then the electrical capacitance is secured, but light transmittance is reduced due to absorption and reflection in thin film layers
Solution Approach 1:
The film thicknesses of the pixel electrode, translucent electrodes, and interlayer insulator film are precisely controlled within specific ranges (100-150 nm for electrodes, 150-200 nm for insulator) to optimize the balance between electrical capacitance and light transmittance. By adjusting these parameters, the patent achieves peak transmittance in the visible light wavelength range while maintaining the required capacitance value.
Solution Approach 2:
The patent uses composite material structures including ITO transparent conductive films for electrodes and silicon oxide films for the interlayer insulator. These materials are selected and combined to provide both the necessary electrical properties for capacitance and optimal optical properties for light transmittance, creating a composite structure that satisfies both requirements simultaneously.
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 allows for high transmittance in the aperture region of the pixel, enabling brighter display quality and efficient light utilization, while maintaining stable film properties and electrical capacitance.
Implementation Method 1
each of film thicknesses of the pixel electrode, the pair of translucent electrodes and the interlayer insulator film are set so that a spectral distribution of light, which is transmitted through the pixel, has peak transmittances corresponding to each of wavelength ranges of at least red, green and blue
Implementation Method 2
there is a concern that it may not be possible to always obtain the predetermined transmittance since the light which transmits the aperture region may be absorbed into the thin film layers
Implementation Method 3
the light may be reflected on an interface of the thin film layers
Data Source
AI summary
A liquid crystal device comprises a first substrate, a second substrate disposed facing the first substrate, a light shielding layer disposed between the first substrate and the second substrate, a transistor disposed above the first substrate, a data line that supplies image signals to the transistor, a scanning line that supplies scanning signals to the transistor and disposed across with the data line, a first transparent electrode disposed between the second substrate and the first substrate, a second transparent electrode disposed between the first transparent electrode and the first substrate, an insulating film disposed between the second transparent electrode and the first substrate, and a third transparent electrode disposed between the insulating film and the first substrate. The light shielding layer overlaps with the transistor in a plan view of the first substrate.