Under-display illumination optical structures

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Solution Overview

Problem

Conventional under-display illumination systems for liquid crystal displays face challenges in efficiently passing light through display micro-structures, leading to reduced illumination efficiency and potential damage to these structures, while also requiring additional space for fingerprint sensors, which complicates device design and user authentication.

Innovation Solution

The implementation of novel optical structures that direct illumination energy through gaps between display micro-structures, utilizing light from the display screen and additional probe light sources to enhance illumination, and integrating optical fingerprint sensors beneath the display to capture fingerprint patterns without the need for separate sensing areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional under-display illumination is used, then illumination energy can pass through the display, but illumination efficiency is reduced and display micro-structures are damaged

Engineering Contradiction:

Improveillumination efficiencyVSAvoiddamage to display micro-structures

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent segments the illumination approach by using multiple optical structures (waveguide, lens array, light field display) to distribute and direct light through different paths, avoiding concentration of energy on single micro-structures and reducing damage while maintaining efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces optical structures as intermediaries between the illumination source and the display micro-structures. These structures (waveguides, lenses, light field displays) mediate the light transmission, enabling efficient illumination while protecting the display micro-structures from direct exposure to high energy

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If separate fingerprint sensor areas are provided, then fingerprint sensing can be achieved, but device space is consumed and design is complicated

Engineering Contradiction:

Improvefingerprint sensing capabilityVSAvoiddevice space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the fingerprint sensor with the display structure by integrating it into the optical structures already present in the display (waveguide, lens array, or light field display). This combination allows fingerprint sensing functionality to be achieved without consuming additional device space or complicating the design

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the optical structures serve multiple functions: they both illuminate the display and enable fingerprint sensing. The same waveguide, lens array, or light field display structure that manages light for display purposes also facilitates fingerprint sensor operation, eliminating the need for separate dedicated components

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach improves illumination efficiency, reduces damage to display micro-structures, and enables compact, reliable fingerprint sensing within the display module, enhancing user authentication and device integration.

Implementation Method 1

output under-display illumination energy and to direct the energy in a manner that passes completely or mostly through gaps between the display micro-structures

Methodology Applied

Scientific EffectOptical transmission through gaps: Light

Implementation Method 2

a liquid crystal display layer in the display panel, the liquid crystal display layer comprising a plurality of liquid crystal cells

Methodology Applied

Scientific EffectLiquid crystal optical modulation: Liquid Crystals

Data Source

PatentUS11320693B2Under-display illumination with external light sources

Publication Date: 2022.05.03 SHENZHEN GOODIX TECH CO LTD

AI summary

Improved under-display illumination is provided for display modules integrated in electronic devices. For example, a display module can include a number of display micro-structures, such as pixels and electrodes. Much of the illumination energy from conventional under-display illumination (e.g., for backlighting) can tend to be blocked by the micro-structures and can also tend to damage the micro-structures. Novel arrangements of optical structures are provided herein to output under-display illumination energy and to direct the energy in a manner that passes completely or mostly through gaps between the display micro-structures. Some implementations provide additional features, such as light conditioning to facilitate transmission of light energy through a dark coating layer, and/or use of multiple optical structures to provide illumination energy with different optical characteristics.