LCD Backlight Through-Hole Layout for Under-Screen Cameras

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Solution Overview

Problem

Existing solutions for achieving a 100% full screen ratio in mobile phones with front cameras result in complex structures, high manufacturing costs, reliability issues, and increased thickness, while also risking damage and allowing entry of dust and water.

Innovation Solution

The electronic device incorporates a liquid crystal module with reduced thicknesses of color resist and black matrix in specific areas and a through hole in the backlight module, allowing the front camera to be positioned under the screen, with a driver chip controlling microelectronic circuits to facilitate both photography and display functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the front camera is disposed on the screen, then the photography function is achieved, but the screen ratio is reduced

Engineering Contradiction:
Improvephotography functionVSAvoidscreen ratio
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The front camera is nested within the display screen structure, positioned in the backlight module below the liquid crystal layer. The camera lens passes through the liquid crystal layer to capture light from the external environment, while the display functions remain intact above it. This nesting approach allows both photography and display functions to coexist in the same spatial footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The solution moves the camera from the traditional front surface (2D plane) to the backlight module dimension (3D depth), utilizing the space below the display screen. This dimensional transition allows the camera to be positioned without occupying screen real estate, achieving 100% screen ratio while maintaining photography capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the front camera is set to lifting structure, then the screen ratio is increased, but the structure complexity and manufacturing cost increase

Engineering Contradiction:
Improvescreen ratioVSAvoidstructure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The camera module is extracted from the traditional front camera position and relocated to the backlight module. This extraction eliminates the need for lifting mechanisms, as the camera remains stationary in the backlight layer. The liquid crystal layer and other display components remain in their original positions, avoiding structural modifications.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical lifting system is replaced with an optical solution where light passes through the liquid crystal layer to reach the camera sensor. This substitution eliminates moving parts, mechanical complexity, and the associated reliability issues while maintaining full-screen display capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If the front camera is placed in sliding cover, then the screen ratio is increased, but the thickness and volume of mobile phone increase

Engineering Contradiction:
Improvescreen ratioVSAvoidthickness
Core Design Contradiction:
Area of stationary objectVSLength of stationary object

Solution Approach 1:

The camera is nested within the existing backlight module structure, utilizing the available space in the display assembly. This nesting approach avoids adding external sliding covers or protruding structures, maintaining the phone's original thickness profile while accommodating the camera functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Area of stationary object

If lifting structure or sliding cover is used, then screen ratio is increased, but reliability decreases and damage risk increases

Engineering Contradiction:
Improvescreen ratioVSAvoidcamera reliability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The camera is extracted from vulnerable moving structures (lifting mechanisms, sliding covers) and positioned in the stable backlight module. This extraction removes the camera from environments prone to mechanical failure, bumping damage, and dust/water ingress, significantly improving reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The camera is positioned within the protected backlight module structure, which provides inherent mechanical protection and sealing. This prior protective arrangement prevents damage before it can occur, eliminating the need for additional protective mechanisms while maintaining full-screen display.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 enables 100% full-screen design by ensuring adequate light input for clear images during photography and maintaining display functionality without increasing thickness or compromising reliability.

Implementation Method 1

setting a first liquid crystal layer in the light-transmitting area of the liquid crystal display panel to allow a portion of the liquid crystal display panel corresponding to the light-transmitting area in a display state

Methodology Applied
Scientific EffectLiquid crystal light modulation: Liquid Crystals

Implementation Method 2

the thicknesses of color resist and a black matrix in the first area, at a corresponding position of a light-transmitting area, of the color filter substrate are smaller than the thicknesses of color resist and a black matrix outside the first area

Methodology Applied
Scientific EffectLight absorption and transmittance: Absorption (EM radiation)

Data Source

PatentEP4134732B1Electronic device and driving method therefor
Publication Date: 2026.01.28 JRD COMM (SHENZHEN) LTD
  • EP4134732B1 patent drawingFigure 1
  • EP4134732B1 patent drawingFigure 2
  • EP4134732B1 patent drawingFigure 3

AI summary

An electronic device (100) and a driving method therefor. The color resistance and the thickness of a black matrix in a first area (120), at a corresponding position of a light-transmitting area (110), of a color film substrate (102) are smaller than color resistance and the thickness of the black matrix outside the first area (120), a backlight module (20) is provide with a through hole (210) opposite to the light-transmitting area (110), and a photographing module (30) and the through hole (210) are oppositely provided, so that external light rays can be obtained by means of the through hole (210) and the light-transmitting area (110), thus under-screen photographing is achieved, and 100% full-screen design is satisfied.