In-Cell Display Touch Inspection Circuit Integration
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Solution Overview
Problem
In-cell type display panels face challenges in inspecting touch sensing function defects using auto-probe test methods, leading to increased production time and costs due to the need for separate inspection processes, which can affect yield and manufacturing efficiency.
Innovation Solution
Incorporating a touch inspection circuit with touch inspection switches and control switches in the non-display area of the display apparatus, allowing for simultaneous inspection of image display and touch sensing functions using an auto probing unit, enabling identification of defects like shorts between touch lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate touch panel is attached to the display apparatus (add-on type), then the image output function and touch sensing function can be independently driven and inspected, but the weight and thickness of the display apparatus increase
Solution Approach 1:
The patent combines the touch sensing function with the display panel by sharing the touch electrode layer with the display pixel structure. The touch electrode layer is integrated into the display panel assembly, allowing both image output and touch sensing functions to coexist in a single integrated structure, thereby reducing weight and thickness while maintaining independent inspection capability through dedicated inspection circuits
2Reliability
If a separate touch panel is attached to the display apparatus (add-on type), then the image output function and touch sensing function can be independently driven, but light emitted from the display panel is lost in transmission through the touch panel, causing degradation in display characteristics
Solution Approach 1:
The patent merges the touch electrode layer with the display panel structure, positioning the touch electrode layer as part of the display panel assembly. This integration eliminates the air gap and multiple interfaces between the display panel and touch panel, reducing light loss at interfaces and improving overall light transmission efficiency while maintaining independent function operation through separate driving circuits
3Weight of stationary object
If at least one component is shared for the image output function and the touch sensing function (in-cell type), then the display apparatus achieves light-weight and small-thickness, but the image output function and touch sensing function are driven in a time-division manner, affecting the defect rate inspection
Solution Approach 1:
The patent segments the inspection process by providing separate inspection circuits for the image output function and touch sensing function. The touch inspection circuit includes dedicated touch inspection switches and inspection pads that are electrically connected to the touch electrode layer, allowing independent inspection of touch function defects without interfering with the image output function inspection
Solution Approach 2:
The patent makes the inspection pad serve multiple functions: it serves as both an inspection pad for the image output function and as a connection point for the touch inspection circuit. This multi-functionality allows the same physical structure to support both inspection processes simultaneously, improving defect inspection accuracy while maintaining the lightweight in-cell structure
4Reliability
If a separate pad for touch inspection is added to the auto-probe test method, then the touch function can be inspected, but the production time and manufacturing cost increase
Solution Approach 1:
The patent merges the touch inspection pad with the existing auto-probe inspection pad structure. The touch inspection circuit shares the same inspection pad infrastructure as the image output function inspection, allowing both touch function and image output function to be inspected using the same auto-probe test equipment and process, thereby eliminating additional production time and cost
Data Source
AI summary
A display apparatus according to an example embodiment may include: a substrate including a display area and a non-display area outside the display area; a plurality of pixels in the display area; a plurality of touch electrodes overlapping with the pixels in the display area; a gate driving circuit in the non-display area and connected to the touch electrodes via at least one gate driving line; and a touch inspection circuit in the non-display area and connected to the touch electrodes through at least one touch line, the touch inspection circuit including at least one touch inspection switch and a touch inspection control switch.