Capacitance Element Groove for Electro-Optical Device
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Solution Overview
Problem
In electro-optical devices, particularly projection-type display devices, the capacitance of capacitance elements decreases when pixel pitch is narrowed, and ensuring a high pixel opening ratio is challenging due to the small plane area of the capacitance element, which limits the device's performance.
Innovation Solution
The electro-optical device incorporates a groove that extends through both interlayer insulating films, positioning the capacitance element to include a portion between the pixel electrode and another portion along the inner wall of the groove, enhancing capacitance while maintaining a high pixel opening ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel pitch is narrowed to increase resolution, then display quality is improved, but capacitance of the capacitance element decreases due to reduced plane area
Solution Approach 1:
The capacitance element is configured to extend in the thickness direction (vertical dimension) by forming a groove in the interlayer insulating film and positioning the capacitance element within this groove. This three-dimensional configuration allows the capacitance element to achieve larger capacitance value without increasing the planar area, thereby resolving the contradiction between narrowed pixel pitch (improved display quality) and reduced capacitance (due to smaller plane area).
2Measurement precision
If pixel pitch is narrowed to increase resolution, then display quality is improved, but pixel opening ratio decreases due to limited space for capacitance element
Solution Approach 1:
By configuring the capacitance element to extend in the thickness direction through groove formation, the invention utilizes the vertical dimension to accommodate the capacitance element. This approach minimizes the occupation of planar area, allowing the pixel opening ratio to be maintained at a high level even when pixel pitch is narrowed for improved display quality.
3Measurement precision
If capacitance element plane area is reduced to accommodate narrowed pixel pitch, then resolution is improved, but capacitance value decreases
Solution Approach 1:
The invention forms a groove in the interlayer insulating film and positions the capacitance element within this groove, causing the capacitance element to extend in the thickness direction. This three-dimensional configuration enables the capacitance element to achieve larger capacitance value without increasing the planar area, thereby resolving the contradiction between improved resolution (from narrowed pixel pitch) and reduced capacitance value (from reduced plane area).
Solution Approach 2:
The capacitance element is nested within the groove structure formed in the interlayer insulating film. This nesting configuration allows the capacitance element to utilize the vertical space within the groove, effectively increasing capacitance without occupying additional planar area that would be needed for resolution improvement.
Data Source
AI summary
In an electro-optical device, at a position overlapping in plan view with a data line, a groove is provided that extends through a first interlayer insulating film provided in a layer between a scan line and a transistor, and a second interlayer insulating film provided in a layer between the transistor and a pixel electrode, and reaches a substrate body. A capacitance element includes a first element portion provided between the second interlayer insulating film and the pixel electrode, and a second element portion provided along an inner wall of the groove. The groove reaches an intermediate position in a thickness direction of the substrate body, and a depth is 3 μm or greater. Therefore, capacitance of the capacitance element is large. A contact hole that electrically couples a gate electrode and the scan line is provided on a side of a semiconductor film.