Display Timing Controller Privacy Mode PWM Brightness Control

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Solution Overview

Problem

Existing information handling systems face challenges in efficiently managing privacy modes at displays, as previous methods limit maximum brightness in privacy mode, result in slow response, increased complexity, and compatibility issues.

Innovation Solution

A system and method that modify display brightness locally using a processing resource, such as a timing controller or extra MCU, to reduce brightness by 20 to 30 nits when a privacy mode is selected, allowing full range of brightness settings and maintaining readability for authorized users while reducing visibility for unauthorized viewers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the information handling system coordinates brightness reduction through software updates, then privacy mode can be implemented, but response time increases and system complexity increases

Engineering Contradiction:

Improveprivacy mode implementationVSAvoidresponse time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The brightness reduction function is extracted from the information handling system and relocated to the display device itself. The display contains a processing resource that can independently modify PWM signals and generate reduced brightness output without requiring software coordination or updates from the host system, thereby eliminating response time delays and reducing system complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The display device performs self-service by incorporating the privacy mode functionality within its own architecture. The processing resource in the display automatically processes privacy mode requests and generates appropriate reduced brightness output without requiring external system coordination, making the system more responsive and simpler to implement.

Inventive Principle:

Principle #25Self-service

2Reliability

If the information handling system coordinates brightness reduction through software updates, then privacy mode can be implemented, but device complexity increases

Engineering Contradiction:

Improveprivacy mode implementationVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The display's processing resource acts as an intermediary between the information handling system and the backlight. It receives PWM signals from the host system, processes them according to privacy mode requirements, and generates modified signals to control the backlight brightness, thereby simplifying the overall system architecture by centralizing the control function.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a camera or sensor monitors the viewing area to detect unauthorized viewers, then privacy mode can be activated, but device complexity and cost increase

Engineering Contradiction:

Improveprivacy mode activationVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of implementing complex sensor-based monitoring systems, the patent applies a simpler approach by using display orientation characteristics and PWM signal processing to achieve privacy mode. The system relies on the inherent properties of display viewing angles and signal processing rather than adding separate detection hardware, thereby reducing complexity while maintaining privacy protection.

Inventive Principle:

Principle #16Partial or excessive action

4Object-affected harmful factors

If the display brightness is reduced to provide privacy, then unauthorized viewers cannot read the display, but authorized users may have difficulty reading in high ambient light conditions

Engineering Contradiction:

Improveunauthorized viewingVSAvoidreadability for authorized users

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system dynamically adjusts display brightness based on multiple factors including ambient light conditions, viewing angle, and privacy mode status. The processing resource in the display can modulate PWM signals to provide different brightness levels - maintaining high brightness for authorized users in bright environments while reducing brightness for off-axis viewing angles to protect privacy, thereby simultaneously satisfying both readability and privacy requirements.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11663367B1Display managed privacy mode to present information handling system visual images

Publication Date: 2023.05.30 DELL PROD LP

AI summary

An information handling display presents visual images in a privacy mode that manages visual image brightness with a local processing resource when a predetermined condition is detected, such as multiple individuals in the display field of view. For example, an information handling system provides visual information to a display timing controller that includes a pulse width modulation signal to command display backlight brightness. When in a privacy mode, the timing controller or another processing resource modifies the pulse width modulation signal to command a predetermined reduced brightness, such as in a range of 30 to 50 nits of reduced brightness.