Parallax Reduction in Dual Modulation Displays

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Solution Overview

Problem

Current display technologies are unable to faithfully reproduce high dynamic range images due to limitations in parallax reduction, leading to suboptimal viewing quality and contrast ratios.

Innovation Solution

The implementation of a display system that reduces parallax through a combination of methods including collimating the backlight, using a textured diffuser, and employing lambertian reflectors to minimize the solid angle and increase diffusion, thereby reducing unwanted light directionality and enhancing image clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional display technologies are used, then device complexity is low, but parallax reduction capability is insufficient

Engineering Contradiction:

Improveparallax reductionVSAvoiddisplay structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The backlight unit is segmented into multiple independently controllable light sources (e.g., LED arrays) that can be selectively activated or dimmed to reduce parallax effects in specific regions of the display, allowing precise control over light directionality without requiring complete structural redesign

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Lambertian reflectors are introduced as intermediary elements between the light sources and the display panel. These reflectors modify the angular distribution of light, converting directional light into more diffuse illumination that reduces parallax while maintaining brightness uniformity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the solid angle of the backlight is decreased to reduce parallax, then viewing quality improves, but light output intensity may be reduced

Engineering Contradiction:

Improveviewing qualityVSAvoidbacklight output

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The display system dynamically adjusts the illumination characteristics by controlling multiple independent light sources and their corresponding reflectors. The solid angle and intensity of each light source can be independently modulated to optimize the balance between parallax reduction and brightness output based on viewing conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The angular distribution parameter of the backlight is changed by introducing Lambertian reflectors that transform the radiation pattern of the light sources. This parameter change reduces the effective solid angle for direct viewing (reducing parallax) while the reflectors redirect light to maintain overall illumination intensity

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If diffusion/scattering is increased at the output to reduce parallax, then image fidelity improves, but light absorption increases

Engineering Contradiction:

Improveimage fidelityVSAvoidlight absorption

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

Instead of applying strong diffusion throughout the entire light path, the invention applies moderate diffusion selectively at the output stage where it is most effective for parallax reduction. This partial action approach achieves sufficient image fidelity improvement without the excessive light absorption that would result from strong diffusion applied earlier in the optical path

Inventive Principle:

Principle #16Partial or excessive action

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 approach results in improved viewing quality and contrast ratios exceeding 1000:1, maintaining brightness while minimizing artifacts and absorption, effectively addressing the limitations of existing display technologies.

Implementation Method 1

increasing diffusion/scattering at an output of the display

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

increasing diffusion/scattering at an output of the display

Methodology Applied

Scientific EffectScattering: Scattering

Implementation Method 3

a collimated backlight structure with substantially lambertian reflectors

Methodology Applied

Scientific EffectCollimation: Lens

Implementation Method 4

lambertian reflectors wherein each reflector surrounds one of the light sources

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS9810943B2Parallax reduction

Publication Date: 2017.11.07 DOLBY LABORATORIES LICENSING CORP

AI summary

Parallax in an optical device is reduced by apply one or a combination of several disclosed techniques, including reduced solid angle or increased collimation of light sources, increased diffusion/scattering at an output of the device, and/or reflective structures for collimation and containment of reflected light. The techniques are advantageously applied to a backlight LCD display, and particularly to high dynamic range dual modulation displays.