Liquid Crystal Display Sensor Noise Reduction via Light Shielding

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Solution Overview

Problem

Liquid crystal display devices with integrated sensors for biometric information detection face accuracy issues due to reflected light from collimation layers, leading to noise in detection signals.

Innovation Solution

The implementation of a structured substrate configuration with collimation layers, light shielding layers, and insulating layers in liquid crystal display devices, where the collimation layers have specific openings and orientations to parallelize incident light and reduce noise by absorbing or blocking stray reflections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If collimation layers are arranged above sensors to block diagonal incident light, then light blocking capability is improved, but reflected light from the back surface of the collimation layer still reaches the sensor causing noise

Engineering Contradiction:

Improvediagonal incident light blockingVSAvoiddetection accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

A light shielding layer is introduced as an intermediary component between the sensor and the collimation layer. This light shielding layer absorbs or blocks the reflected light from the back surface of the collimation layer before it reaches the sensor, thereby eliminating the noise source while preserving the collimation layer's light blocking function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The reflected light from the collimation layer back surface, which was originally a harmful noise source, is redirected toward the light shielding layer. The light shielding layer then absorbs this reflected light, converting the potentially harmful reflection into a controlled interaction that prevents noise from reaching the sensor.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If multiple layers (collimation layer, insulating layer, light shielding layer) are arranged between sensor and liquid crystal layer, then noise reduction is improved, but device structure complexity increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidsubstrate structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The insulating layer serves multiple functions: it provides electrical insulation between different conductive layers and simultaneously acts as a structural support layer that maintains the spacing and positioning of the collimation layer and light shielding layer. This multi-functionality reduces the need for additional dedicated layers.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The light shielding layer is integrated into the existing substrate structure by positioning it between the insulating layer and the base member, merging it with the overall layered architecture rather than adding it as a separate external component. This integration approach minimizes structural complexity while achieving noise reduction.

Inventive Principle:

Principle #5Merging (Combining)

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 accuracy of biometric information detection by minimizing noise in sensor signals, improving the overall detection precision of fingerprint and other biometric data.

Implementation Method 1

one or more collimation layers to block diagonal incident light are arranged

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Implementation Method 2

the light shielding layer is positioned between the sensor and the base member, and overlaps with an outer peripheral part of the first collimation layer

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

The sensors may be optical sensors using, for example, photoelectric conversion elements

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS11550429B2Liquid crystal display device

Publication Date: 2023.01.10 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a liquid crystal display device comprises first and second substrates and a liquid crystal layer. The first substrate includes a base member, a sensor between the base member and the liquid crystal layer, a collimation layer between the sensor and the liquid crystal layer, an insulating layer between the sensor and the collimation layer, an insulating layer, and a light shielding layer between the sensor and the base member. The sensor is configured to output a signal corresponding to light incident from a liquid crystal layer side. The light shielding layer overlaps with an outer peripheral part of the first collimation layer.