Under-Display TOF Module Light Shielding Design
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Solution Overview
Problem
The integration of a front-facing photographing device, such as a Time of Flight (TOF) module, into bezel-less mobile terminals interferes with the display screen, reducing the overall screen-to-body ratio and aesthetic appeal due to the need for a staggered arrangement and screen-printed transparent openings in the cover plate.
Innovation Solution
The TOF module is positioned under the display panel, with a light shielding layer on the display panel to prevent interference and allow infrared light to pass through specific regions, eliminating the need for a screen-printed transparent opening and reducing the black margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the TOF photographing module is arranged in a staggered manner under the cover plate with a screen-printed transparent opening, then the photographing module can function properly, but the overall screen-to-body ratio is reduced and aesthetic appeal is compromised
Solution Approach 1:
The patent transitions from a two-dimensional arrangement (staggered placement under cover plate) to a three-dimensional stacked arrangement. The TOF photographing module is positioned directly beneath the display panel in the same planar projection area, utilizing the Z-axis dimension (depth) to resolve the conflict between module functionality and screen-to-body ratio. This vertical stacking eliminates the need for lateral offset and cover plate openings.
Solution Approach 2:
The TOF photographing module is nested within the display assembly structure, positioned in the space between the display panel and the back cover. The module is effectively 'nested' in the vertical stack of components, allowing it to occupy space that does not interfere with the front display surface while maintaining full functionality.
2Reliability
If the TOF photographing module transmits infrared light through the display screen, then the module can operate, but the infrared light interferes with the TFT circuit and forms light spots impacting display quality
Solution Approach 1:
The patent extracts the infrared light transmission path from the general display area by creating a dedicated light transmission region. The TFT circuit is removed or avoided from this specific region, separating the infrared transmission function from the display function. This extraction allows infrared light to pass through without interfering with TFT circuits that would otherwise be present in the entire display area.
Solution Approach 2:
The display panel is designed with spatially varying properties: a light transmission region with higher infrared transparency and a display region with standard TFT circuit coverage. This local differentiation of optical properties and circuit distribution allows the same display panel to serve dual functions - displaying visual information in most areas while transmitting infrared light in the specific region needed for the TOF module.
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
This configuration enhances the screen-to-body ratio and aesthetic appeal by preventing light interference with the display panel while allowing the TOF module to function unhindered, thereby improving the mobile terminal's design and functionality.
Implementation Method 1
A first region of the display panel facing the photographing module is provided with a light shielding layer for shielding light at a predetermined wavelength
Data Source
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Figure 3~4
AI summary
A mobile terminal is provided. The mobile terminal includes: a housing, a cover plate, a display panel and a photographing module, where an accommodation space is formed between the housing and the cover plate, the display panel and the photographing module are provided in the accommodation space, the photographing module is provided on a side of the display panel away from the cover plate; a first region of the display panel facing the photographing module is provided with a light shielding layer for shielding light at a predetermined wavelength, and the light at the predetermined wavelength is allowed to pass through a second region of the display panel facing the photographing module.