In-cell Touch Panel Embedded in Display Substrate
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Solution Overview
Problem
Conventional touch panels for flat panel display devices, especially OLEDs, face issues such as increased device thickness and degradation of display brightness in add-on types, and exposure of touch panel elements to atmospheric conditions in on-cell types, leading to potential damage during manufacturing.
Innovation Solution
An in-cell touch panel is embedded within the upper glass substrate of flat panel display devices, featuring a transparent substrate with conductive routing parts, sensor lines, driving lines, insulating layers, and a connecting part, which are designed to maintain image quality and protect touch panel elements by using transparent conductive materials and a layered insulating structure to minimize parasitic capacitance and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If add-on type touch panel is attached on the outer surface of upper substrate, then touch panel elements are protected from atmospheric exposure, but device thickness increases and display brightness degrades
Solution Approach 1:
The patent merges the touch panel structure with the display device's upper substrate by forming touch panel elements (sensor lines, driving lines, signal lines) directly on the inner surface of the upper glass substrate. This integration eliminates the need for a separate add-on touch panel layer, thereby reducing overall device thickness while maintaining element protection through the substrate itself and insulating layers.
Solution Approach 2:
The touch panel elements are nested within the upper substrate structure, specifically on its inner surface. The sensor lines, driving lines, and signal lines are embedded within the substrate thickness, with insulating layers providing additional protection. This nesting approach allows the touch panel to be housed within the existing display structure rather than adding external layers.
2Length of stationary object
If on-cell type touch panel elements are formed on the outer surface of cap glass, then device thickness is reduced, but touch panel elements are exposed to atmospheric conditions and can be damaged during manufacturing
Solution Approach 1:
The patent transitions from forming touch panel elements on the outer surface (2D plane) to forming them on the inner surface of the upper substrate. This dimensional reversal allows the elements to be protected by the substrate itself, which acts as a protective barrier against atmospheric exposure and manufacturing damage, while still maintaining a thin overall profile.
Solution Approach 2:
The touch panel elements are formed during the display device manufacturing process itself, before final assembly and sealing. The sensor lines, driving lines, and signal lines are patterned on the inner surface of the upper glass substrate during the same manufacturing sequence as the display structure, ensuring elements are protected from the outset rather than requiring post-manufacturing protection.
3Illumination intensity
If transparent conductive materials are used for routing parts and lines, then image quality is maintained, but parasitic capacitance and noise may increase
Solution Approach 1:
The patent applies different material properties to different regions: transparent conductive materials (such as ITO) are used specifically for the sensor lines and signal lines where transparency is critical for display brightness, while driving lines use transparent insulating materials that provide electrical isolation. This localized material selection optimizes both optical performance and electrical characteristics in different functional areas.
Solution Approach 2:
The patent introduces transparent insulating layers as intermediary structures between the conductive elements and the liquid crystal layer. These insulating layers (formed by organic insulating materials) act as mediators that reduce parasitic capacitance between the transparent conductive lines and the liquid crystal, thereby minimizing noise while maintaining the transparency needed for display brightness.
Data Source
AI summary
The present disclosure relates to an in-cell touch panel embedded into the flat panel display devices. The present disclosure suggests an in-cell touch panel for flat panel display device comprising: a transparent substrate; a routing part having a conductive material formed on an inner side of the transparent substrate; a plurality of sensor lines running to a first direction on the inner side of the transparent substrate; a plurality of driving lines that each driving line has a plurality of segments running to a second direction between the sensor lines; a first insulating layer covering the sensor lines and the driving lines; a connecting part linking the segments of the driving line to the second direction; and a second insulating layer covering the whole surface of the transparent substrate having the connecting part.