Display Driving Circuit With Wavelength Correction for Color Drift

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Solution Overview

Problem

Display apparatuses using pulse width modulated drive suffer from complexity, difficulty in achieving high pixel definition, and susceptibility to flickering due to short pulses, leading to degraded image quality and possible color drift.

Innovation Solution

A display apparatus utilizing a current amplitude modulation scheme with a driving circuit, multiple light emitting elements, and a wavelength correcting layer to correct emission wavelengths, including a color filter or bandpass filter to independently gamma-correct signals, reducing circuit complexity and suppressing color drift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pulse width modulated drive is used, then the display apparatus can be driven, but the circuit becomes complicated and pixel definition cannot be improved

Engineering Contradiction:

Improvecircuit complexityVSAvoidpixel definition

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces the pulse width modulated drive system with a current amplitude modulated drive system. This substitution changes the fundamental driving mechanism from time-based pulse control to current-based amplitude control, thereby simplifying the circuit structure while enabling higher pixel definition through reduced circuit complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If current amplitude modulation scheme is used, then circuit complexity is reduced, but color drift occurs due to emission wavelength shift

Engineering Contradiction:

Improvecircuit complexityVSAvoidimage quality

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces a wavelength correcting layer as an intermediary component between the light emitting element and the external environment. This layer corrects the emission wavelength shift caused by current amplitude modulation, preventing color drift and maintaining image quality while allowing the use of the simpler current amplitude modulation scheme

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs independent gamma correction for different color channels (first and second signals for first and second light emitting elements respectively). By adjusting the gamma parameters independently for each color channel, the system compensates for wavelength shifts and maintains accurate color reproduction under current amplitude modulation

Inventive Principle:

Principle #35Parameter changes

3Reliability

If pulse width modulated drive is used, then the display can operate, but flickering occurs at low luminance

Engineering Contradiction:

Improveimage qualityVSAvoidluminance

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent replaces the pulse width modulated drive with current amplitude modulated drive to eliminate flickering. By using continuous current modulation instead of pulsed signals, the system maintains stable light emission at all luminance levels, particularly eliminating the flickering that occurs at low luminance in PWM-driven displays

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 suppresses image quality degradation by correcting wavelength shifts and reducing manufacturing costs, enabling high-definition displays with simplified structures and improved luminous efficiency.

Implementation Method 1

a wavelength correcting layer that is able to correct wavelengths of light emitted from the multiple first light emitting elements

Methodology Applied

Scientific EffectWavelength correction: Filter (optical)

Implementation Method 2

The wavelength correcting layer may include at least one type selected from a group including a color filter

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

multiple first light emitting elements and multiple second light emitting elements two-dimensionally arranged on the board

Methodology Applied

Scientific EffectLight emission: Light Emitting Diode

Data Source

PatentUS12417732B2Display apparatus and electronic equipment

Publication Date: 2025.09.16 SONY GROUP CORP

AI summary

Provided is a display apparatus that can suppress degradation of image quality caused by possible color drift. A display apparatus includes a board including a driving circuit based on a current amplitude modulation scheme, multiple first light emitting elements and multiple second light emitting elements two-dimensionally arranged on the board, and a wavelength correcting layer that is able to correct wavelengths of light emitted from the multiple first light emitting elements. The driving circuit is able to independently gamma-correct a first signal fed to the first light emitting element and a second signal fed to the second light emitting element.