Organic Film Overflow Detection in OLED Encapsulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The organic light emitting display devices face issues due to overflow of the organic film during encapsulation, leading to defects such as driving defects and degradation of the organic light emitting diode, which are difficult to detect visually due to the transparent nature of the polymer material used.
Innovation Solution
A display device design that includes a dam between the display area and the pad area to prevent organic film overflow and a conductive testing line to detect any overflow, allowing for the detection of defects and preventing exposure of the organic film to the outside, thereby preventing degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the organic film is made transparent to maintain coating performance, then coating performance is improved, but defect detection becomes difficult
Solution Approach 1:
The patent applies color change principle by forming an inorganic film with specific optical properties that interacts with the transparent organic film. When the organic film overflows onto the conductive testing line, it changes the electrical conductivity, which can be detected through electrical measurement rather than visual inspection. This resolves the contradiction by providing a detection method that works regardless of the organic film's transparency.
Solution Approach 2:
The patent replaces visual detection (mechanical/optical system) with electrical detection system. Instead of relying on visual inspection of the transparent organic film, the invention uses electrical conductivity measurement of the conductive testing line to detect organic film overflow, thereby solving the detection difficulty while maintaining the transparent coating performance.
2Area of stationary object
If the organic film overflows outside the encapsulation area, then coating coverage is improved, but encapsulation effectiveness deteriorates
Solution Approach 1:
The patent segments the encapsulation structure into distinct functional zones: the encapsulation film covering the display area, the dam structure defining the boundary, and the conductive testing line in the non-display area. This segmentation allows the organic film to extend into the non-display area for complete coverage while preventing it from compromising the encapsulation effectiveness in the display area through the dam boundary.
Solution Approach 2:
The dam structure serves as an intermediary element between the encapsulation area and the non-display area. It controls and directs the organic film flow, allowing the film to cover the intended areas while preventing uncontrolled overflow that would compromise encapsulation effectiveness. The conductive testing line acts as another intermediary to monitor and detect the film position.
3Device complexity
If the organic film is not encapsulated by the second inorganic film, then manufacturing complexity is reduced, but degradation resistance deteriorates
Solution Approach 1:
The patent applies preliminary action by forming the dam structure and conductive testing line before depositing the organic film. This allows the organic film to be deposited in a controlled manner, ensuring it is properly encapsulated by the second inorganic film where needed while extending into the non-display area where encapsulation is not required, thereby maintaining degradation resistance without unnecessary manufacturing complexity.
Solution Approach 2:
The patent applies local quality principle by providing different levels of encapsulation protection in different areas: the display area receives full encapsulation protection with multiple inorganic films, while the non-display area has controlled organic film extension without requiring the same level of encapsulation. This resolves the contradiction by matching the encapsulation complexity to the actual protection needs of each region.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A display device and a testing method thereof are disclosed, in which a defect caused by an overflow of an organic film (292) constituting an encapsulation film (290) can be detected. The display device comprises a substrate (111) including a display area (DA) where pixels are arranged, and a pad area (PA) including a plurality of pads formed outside the display area; an encapsulation film (290) covering the display area, including at least one inorganic film (291) and at least one organic film (292); a dam (120) arranged between the display area and the pad area; and a conductive testing line (130) arranged between the dam (120) and the pad area (PA) and not electrically connected with another conductive line or electrode arranged on the substrate (111).