Display Device Input Sensing Part Parasitic Capacitance Reduction
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Solution Overview
Problem
Parasitic capacitors formed between sensor parts and pixels in display devices affect touch sensitivity due to noise in the input signal generated by the input sensing part.
Innovation Solution
The display device incorporates a substrate with pixel areas and a non-pixel area, featuring a pixel defining film with first and second openings, light emitting elements, and an input sensing part overlapping the second opening, which includes sensor parts with a mesh shape and branch parts to reduce parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If sensor parts are disposed close to pixel areas for compact design, then device area is reduced, but parasitic capacitance increases affecting touch sensitivity
Solution Approach 1:
The pixel defining film serves as an intermediary structure between the sensor parts and pixel areas. By forming this film with specific opening patterns, it acts as a mediator that reduces parasitic capacitance while allowing the sensor parts to remain in close proximity to pixel areas for compact device design.
Solution Approach 2:
The pixel defining film is designed with different opening patterns in different regions: first openings in pixel areas and second openings in non-pixel areas. This local differentiation allows the film to reduce parasitic capacitance specifically where needed while maintaining compact sensor placement.
2Measurement precision
If sensor parts are disposed overlapping pixel areas, then touch detection coverage is improved, but noise from parasitic capacitors increases
Solution Approach 1:
The pixel defining film is segmented into multiple regions with different opening patterns: first openings overlapping pixel areas and second openings overlapping non-pixel areas. This segmentation allows the sensor parts to overlap pixel areas for comprehensive touch detection while the film structure minimizes parasitic capacitance and associated noise.
Solution Approach 2:
The pixel defining film acts as an intermediary layer between the sensor parts and the underlying structures. Its specific opening configuration mediates the interaction between sensor parts and pixel areas, enabling good touch detection coverage while reducing parasitic capacitance effects.
3Reliability
If pixel defining film is formed with multiple openings, then parasitic capacitance is reduced, but manufacturing complexity increases
Solution Approach 1:
The pixel defining film performs multiple functions simultaneously: it defines pixel boundaries, reduces parasitic capacitance through its opening pattern, and provides structural support. By combining these functions into a single component with a specific opening pattern, the design reduces parasitic capacitance without proportionally increasing manufacturing complexity.
Data Source
AI summary
A display device includes: a substrate including a plurality of pixel areas and a non-pixel area at least partially surrounding each of the pixel areas; an element layer disposed on the substrate; a pixel defining film disposed on the element layer, wherein the pixel defining film includes first openings and a second opening, wherein the first openings overlap the plurality of pixel areas, and the second opening overlaps the non-pixel area and extends along the plurality of pixel areas; a plurality of light emitting elements disposed in the first openings; a sealing layer disposed on the element layer to cover the light emitting elements and the pixel defining film; and an input sensing part overlapping the second opening and disposed on the sealing layer.