Rollable Display Panel Acoustics With Flexible Piezo Vibration Modules
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Solution Overview
Problem
Existing display apparatuses face issues with sound quality and durability due to interference and brittleness of sound systems, particularly in flexible rollable displays, where piezoelectric elements are prone to damage and have limited sound pressure and power consumption challenges.
Innovation Solution
A display apparatus with vibration modules on the rear surface of a display panel, including rigid members to support the panel and increase mass, and piezoelectric portions to enhance sound pressure and resonance frequency, allowing the panel to be wound or unwound while maintaining sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a piezoelectric element is applied to the display apparatus to reduce thickness, then the display apparatus becomes thinner, but the piezoelectric element is likely to be damaged by external impact due to its brittleness property, whereby reliability in sound reproduction is low
Solution Approach 1:
The patent changes the material parameter from brittle piezoelectric ceramic to flexible piezoelectric polymer, fundamentally altering the mechanical properties while maintaining piezoelectric functionality. This allows the sound system to remain thin while improving durability against external impact
Solution Approach 2:
The patent uses a composite structure combining flexible piezoelectric polymer with electrodes and flexible substrates. This composite approach maintains the thin profile while the flexible polymer matrix provides impact resistance, resolving the contradiction between thinness and reliability
2Area of stationary object
If a film-type vibration module is applied to the display apparatus to manufacture with large area, then the film-type vibration module may be applied to a large scaled display apparatus, but it is difficult for the film-type vibration module to have a large area due to low vibration caused by a low piezoelectric property
Solution Approach 1:
The patent changes the piezoelectric material parameter to use high-d3 coefficient flexible piezoelectric polymers, which provide stronger piezoelectric response. This enables large-area vibration modules to generate sufficient vibration for effective sound reproduction in scaled display apparatus
Solution Approach 2:
The patent optimizes the local piezoelectric property by strategically placing piezoelectric elements and electrodes to maximize vibration efficiency across the large area, ensuring uniform and effective sound output throughout the display surface
3Reliability
If a deposited film-type piezoelectric element including several film-type piezoelectric layers is applied to the display apparatus to improve a sound pressure, then the sound pressure is improved, but power consumption is increased
Solution Approach 1:
The patent changes the piezoelectric material to flexible polymer with high piezoelectric coefficients, which generates stronger vibration response with lower driving voltage. This improves sound pressure while reducing power consumption compared to multiple ceramic layers
Solution Approach 2:
The patent extracts the essential function of piezoelectric conversion and implements it through a single-layer flexible polymer structure, eliminating the need for multiple stacked ceramic layers. This simplification reduces power consumption while maintaining or improving sound pressure output
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves stereoscopic sound effects and viewer immersion by matching image and sound generation, enhances sound pressure in low-pitched reproduction, and extends the reproduction frequency band without increasing power consumption.
Implementation Method 1
at least one vibration module on a rear surface of a display panel and wound or unwound together with the display panel to match positions where image and sound of the display apparatus are generated with each other... at least one vibration module includes: a plurality of first portions having a piezoelectric property
Data Source
AI summary
A display apparatus includes: a display panel configured to be rolled or unrolled; at least one vibration module at a rear surface of the display panel, the at least one vibration module being configured to be rolled or unrolled with the display panel and to vibrate the display panel; a partition at the rear surface of the display panel, the partition being spaced apart from and surrounding the at least one vibration module; and a plurality of rigid members at the rear surface of the display panel, the plurality of rigid members extending in a first direction and being spaced apart from each other in a second direction vertical to the first direction in a state in which the plurality of rigid members are not coupled or connected to each other.