Rollable Display Shaft Structure for Winding Stress Reduction
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Solution Overview
Problem
Conventional rollable display apparatuses suffer from defects due to stress during usage, which affects their reliability and performance.
Innovation Solution
A rollable display apparatus design featuring a shaft with half ring portions, a groove and protrusion configuration, and a base layer with a stepped surface to securely fasten the display module, minimizing stress concentration and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rollable display apparatus is designed to be wound around a shaft, then the display module can be rolled up and stored, but stress occurs during winding and unwinding operations leading to defects
Solution Approach 1:
The shaft is designed with non-uniform thickness, being thicker at the first end portion and thinner at the second end portion. This local variation in thickness creates different mechanical properties at different locations, allowing the shaft to better distribute and manage stress during rolling operations, thereby reducing defects while maintaining the rollable function
Solution Approach 2:
A groove is pre-formed at the first end portion of the shaft where stress concentration is expected to occur during winding. This preliminary structural preparation allows the display module to be securely fastened before stress occurs, preventing defects during the rolling operation
2Strength
If the shaft thickness is increased to strengthen the structure, then the shaft can withstand stress better, but the overall device size increases
Solution Approach 1:
Instead of uniformly increasing the shaft thickness throughout, the design applies increased thickness only at the first end portion where stress concentration occurs during winding. The second end portion maintains a thinner profile, thus providing necessary strength where needed while minimizing overall device volume
3Reliability
If a groove is added to fasten the base layer, then the base layer is securely fixed to the shaft, but the manufacturing complexity increases
Solution Approach 1:
The groove is pre-formed during shaft manufacturing at the location where stress concentration is expected to occur. This preliminary action ensures the groove is ready to receive and secure the base layer before the actual rolling operation, providing reliable fastening while integrating the feature into the manufacturing process
Data Source
AI summary
A display apparatus includes a shaft extending in a first direction and including a first half ring portion having a curvature from a first end portion to a second end portion opposite to the first end portion on a plane perpendicular to the first direction, and a second half ring portion having a curvature from a third end portion to a fourth end portion opposite to the third end portion on the plane. The third end portion and the fourth end portion of the second half ring portion are respectively connected to the first end portion and the second end portion of the first half ring portion. The display apparatus includes a groove arranged adjacent to the first end portion of the first half ring portion. The display apparatus includes a base layer including a protrusion fitted into the groove.