Dual-Drive Pixel Circuit for Under-Display Camera Brightness

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Solution Overview

Problem

The low pixel density region in display panels with under-screen cameras has lower luminance due to lower pixel density, affecting display quality and brightness, which is not adequately addressed by existing technologies.

Innovation Solution

A pixel circuit with two driving circuits for each light-emitting element in the low pixel density region, allowing increased driving current and brightness, using transistors like P-type thin film transistors to enhance luminance uniformly across the panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If a transmissive liquid crystal display is used, then the display can be made thinner and lighter, but the response time becomes slower and viewing angles become narrower

Engineering Contradiction:
Improvedisplay weightVSAvoidresponse time
Core Design Contradiction:
Weight of stationary objectVSDuration of action of moving object

Solution Approach 1:

The liquid crystal display is divided into multiple sub-pixels (red, green, blue) arranged in a specific pattern, with each sub-pixel having independent control electrodes. This segmentation allows for optimized control of each color component, improving overall response time while maintaining thin design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic control mechanisms including overdrive voltage adjustment and responsive compensation circuits that adapt to different grayscale transitions. The voltage control system dynamically adjusts driving parameters to accelerate liquid crystal molecule reorientation, reducing response time in thin display structures

Inventive Principle:
Principle #15Dynamics

2Weight of stationary object

If a transmissive liquid crystal display is used, then the display can be made thinner and lighter, but the viewing angle becomes narrower

Engineering Contradiction:
Improvedisplay weightVSAvoidviewing angle
Core Design Contradiction:
Weight of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent implements compensation films with specific optical characteristics positioned at different locations relative to the liquid crystal layer. These films have varying refractive indices and optical axes oriented at specific angles to compensate for viewing angle dependence locally across different viewing directions, expanding effective viewing angles in thin display configurations

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The liquid crystal alignment layers and compensation films are configured with asymmetric optical properties to counteract the symmetric viewing limitations of standard transmissive LCDs. The dual-domain vertical alignment structure creates asymmetric light propagation paths that broaden viewing angles

Inventive Principle:
Principle #4Asymmetry

3Manufacturing precision

If the pixel circuit area is reduced to increase pixel density, then the display resolution improves, but the liquid crystal switching capacity becomes insufficient

Engineering Contradiction:
Improvepixel densityVSAvoidliquid crystal switching capacity
Core Design Contradiction:
Manufacturing precisionVSPower

Solution Approach 1:

The pixel circuit components are nested within the pixel area in a compact arrangement where the compensation circuit is integrated alongside the switching transistor and storage capacitor. This nested configuration maximizes the use of available pixel area, enabling higher pixel density while maintaining sufficient circuit capacity for liquid crystal switching

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent extends the circuit layout into the vertical dimension by stacking certain circuit elements above or below the liquid crystal layer in three-dimensional integration. This dimensional transition allows more circuit functionality to be packed into the same planar pixel area, maintaining switching capacity while increasing pixel density

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

4Manufacturing precision

If the pixel circuit area is reduced to increase pixel density, then the display resolution improves, but the grayscale expression capability becomes insufficient

Engineering Contradiction:
Improvepixel densityVSAvoidgrayscale expression capability
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The compensation circuit is pre-configured with specific capacitance values and resistance ratios that are optimized during manufacturing to provide appropriate grayscale voltage division. This preliminary design ensures that even in reduced pixel areas, the circuit can generate the necessary number of grayscale levels for accurate image representation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent optimizes key circuit parameters including capacitor ratios, resistor values, and transistor width-to-length ratios to maintain grayscale expression capability in compact pixel designs. By carefully adjusting these parameters, the circuit achieves adequate grayscale levels despite reduced area available for component placement

Inventive Principle:
Principle #35Parameter changes

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 increases brightness in the low pixel density region, reducing luminance unevenness and improving display quality by doubling the driving current, thus enhancing the overall display effect.

Implementation Method 1

the liquid crystal 130 changes its molecular arrangement according to the voltage applied thereto

Methodology Applied
Scientific EffectLiquid crystal alignment: Liquid Crystals

Implementation Method 2

the compensation film 170 compensating for a viewing angle dependence of the liquid crystal display

Methodology Applied
Scientific EffectOptical compensation:

Data Source

PatentEP4053831B1Pixel circuit, display substrate, display panel, and display device
Publication Date: 2026.05.20 BOE TECHNOLOGY GROUP CO LTD
  • EP4053831B1 patent drawingFigure 1A~1B
  • EP4053831B1 patent drawingFigure 2
  • EP4053831B1 patent drawingFigure 3A~3B

AI summary

A pixel circuit, a display substrate, a display panel, and a display device. The pixel circuit comprises: a first driving circuit, a second driving circuit, a first light emitting control circuit, a second light emitting control circuit, a storage circuit, and a data writing circuit. The first light emitting control circuit is configured to control connection or disconnection between the first driving circuit and a light emitting element and control connection or disconnection between the first driving circuit and a first power supply line; the second light emitting control circuit is configured to control connection or disconnection between the second driving circuit and the light emitting element and control connection or disconnection between the second driving circuit and a second power supply line; the data writing circuit is configured to write a data voltage into the first driving circuit; the first driving circuit and the second driving circuit are configured to control, on the basis of the same data voltage, a driving current driving the light emitting element to emit light; the storage circuit is configured to maintain voltages of a control end of the first driving circuit and a control end of the second driving circuit.