Micro-LED Backlight with Light Shielding for Crosstalk Reduction

Solution Overview

Problem

Small-sized liquid crystal displays face challenges in achieving effective local dimming and high dynamic range (HDR) due to large light crosstalk between backlight partitions, which impairs picture quality and energy efficiency.

Innovation Solution

A direct type backlight module with micro-LED chips arranged in a matrix array on a printed circuit board, where a light shielding unit is placed between adjacent micro-LED chips to restrict light-emitting angles, combined with a quantum dot thin film layer for color conversion and a heat sink plate for thermal management, allowing independent control of each micro-LED chip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional LED backlight modules are used in small-sized liquid crystal displays, then the device size is reduced, but light crosstalk between partitions increases and HDR effect deteriorates

Engineering Contradiction:

Improvedisplay sizeVSAvoidlight crosstalk

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The backlight is divided into multiple independently controllable partitions through micro-LED chips arranged in a matrix array. Each partition can be controlled separately, enabling local dimming functionality even in small-sized displays. The light shielding units further segment the light paths between adjacent partitions to prevent crosstalk.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Light shielding units are introduced as intermediary elements between adjacent micro-LED chips. These shielding units block stray light from one partition from entering adjacent partitions, effectively eliminating light crosstalk while maintaining the compact form factor.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If more partitions are implemented in the backlight, then local dimming effect and dynamic contrast are improved, but light crosstalk between partitions increases in small-sized displays

Engineering Contradiction:

Improvelocal dimming effectVSAvoidlight crosstalk

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The backlight is divided into multiple independently controllable partitions through micro-LED chips arranged in a matrix array. Each partition can be controlled separately, enabling local dimming functionality even in small-sized displays. The light shielding units further segment the light paths between adjacent partitions to prevent crosstalk.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Light shielding units are introduced as intermediary elements between adjacent micro-LED chips. These shielding units block stray light from one partition from entering adjacent partitions, effectively eliminating light crosstalk while maintaining the compact form factor.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Area of stationary object

If micro-LED chips are arranged in a matrix array with small pitch, then the backlight area is reduced for small-sized displays, but light crosstalk between partitions increases

Engineering Contradiction:

Improvebacklight areaVSAvoidlight crosstalk

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

Light shielding units are introduced as intermediary elements between adjacent micro-LED chips. These shielding units block stray light from one partition from entering adjacent partitions, effectively eliminating light crosstalk while maintaining the compact form factor.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The light shielding units are strategically placed only where needed - between adjacent micro-LED chips in the matrix array. This localized approach blocks crosstalk without unnecessarily increasing the overall backlight area, maintaining compactness while preventing light leakage.

Inventive Principle:

Principle #3Local quality

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 effectively reduces light crosstalk between partitions, enhancing the HDR effect and improving picture quality and energy efficiency, especially for small-sized liquid crystal displays.

Implementation Method 1

a quantum dot thin film layer disposed above the light source and emitting red light and green light under an excitation of the blue light emitted from the micro-LED chip

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a light shielding unit is disposed between any adjacent two micro-LED chips

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentUS10514574B2Direct type backlight module and liquid crystal display

Publication Date: 2019.12.24 WUHAN CHINA STAR OPTOELECTRONICS TECH CO LTD

AI summary

The present disclosure discloses a direct type backlight module, which includes a back plate and a light source disposed on the back plate, wherein the light source includes a printed circuit board and a plurality of micro-LED chips electrically connected to the printed circuit board, the plurality of micro-LED chips are arranged in a matrix array on the printed circuit board, and a light shielding unit is disposed between any adjacent two micro-LED chips; and the printed circuit board is further connected with a backlight driving chip thereon which drives each of the plurality of micro-LED chips independently. The present disclosure further provides a liquid crystal display which includes the abovementioned direct type backlight module.