Under-Display Optical Sensor Beam Expansion to Reduce Distortion
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Solution Overview
Problem
Optical sensors behind displays cause display distortion due to high optical power exceeding the bandgap of display semiconductors, leading to trade-offs between sensing distance and distortion.
Innovation Solution
An optical sensor module with a reducer is integrated between the light emitter and the display screen to increase beam diameter and reduce optical power density, using beam shaping optics such as lenses or mirrors to minimize distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a liquid crystal display is used, then power consumption is reduced compared to plasma displays, but liquid crystal material can leak when the seal is broken due to thermal expansion or contraction
Solution Approach 1:
The patent uses a composite sealing structure combining resin material and metal material. The resin portion provides sealing function while the metal flange provides structural strength and thermal stability. This composite approach allows the seal to withstand thermal expansion and contraction forces without breaking, preventing liquid crystal leakage while maintaining the low power consumption benefits of LCD technology.
Solution Approach 2:
The patent modifies the sealing structure by adding a metal flange with specific geometric parameters (protruding portion, recessed portion, grooves) to the existing resin seal. This structural parameter change enhances the seal's ability to accommodate thermal dimensional changes of the glass substrates, maintaining seal integrity under temperature variations while preserving the LCD's energy efficiency.
2Length of stationary object
If the display device is made thinner, then portability is improved, but the structure becomes more complex to maintain sealing and structural integrity
Solution Approach 1:
The patent implements a nested sealing structure where the metal flange is formed integrally with the resin sealing member. The metal flange contains nested grooves and recessed portions that house sealing elements and provide structural support. This nested design achieves thin overall profile while maintaining complex sealing functionality through space-efficient integration of multiple functions within the seal assembly.
Solution Approach 2:
The patent merges the sealing function and structural support function into a single integrated sealing member comprising both resin and metal components. The metal flange is formed as an integral part of the resin sealing member, combining multiple functions (sealing, structural support, thermal management) into one component, thereby reducing overall device complexity despite the thin profile requirement.
3Reliability
If a metal flange is added to prevent liquid crystal leakage, then reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent incorporates the metal flange into the sealing structure during the initial assembly process, before the display device undergoes thermal cycling or operational use. The metal flange is pre-formed and integrated with the resin sealing member in advance, ensuring liquid crystal containment is established before any thermal expansion or contraction occurs, thereby preventing leakage without requiring post-assembly modifications.
Solution Approach 2:
The patent employs a composite sealing structure where the metal flange and resin sealing member are manufactured separately and then assembled together. This approach allows each component to be optimized for its specific manufacturing process (metal forming for the flange, molding for the resin), simplifying fabrication while achieving the reliability benefits of the metal-reinforced seal that prevents liquid crystal leakage.
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
The solution effectively reduces display distortion while maintaining a detection distance of over 30 mm, ensuring minimal optical power density on the display screen.
Implementation Method 1
a light emitter which is operable to produce light having a wavelength for transmission through the display screen
Implementation Method 2
a beam divergence can be tuned... increase beam diameter... tune the beam divergence
Implementation Method 3
a light sensor is operable to sense light reflected by the target object and having the wavelength
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
An apparatus comprises a display screen, and an optical sensor module which is disposed behind the display screen. The optical sensor module further comprises a light emitter operable to generate light having a wavelength for transmission through the display screen toward a target object. A light sensor is operable to sense light reflected by the target object and having the wavelength. A reducer is arranged for reducing the optical power density by increasing a diameter of a light beam generated by the light emitter on the display screen, wherein the reducer is disposed between the light emitter and the display screen so as to intersect the light beam generated by the light emitter.