Backlight Unit Switching 2D and 3D Modes via Collimated Light

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Solution Overview

Problem

Current 3D image display technologies require separate backlight units for 2D and 3D modes, leading to increased complexity and resource requirements, such as multiple light sources and driving circuits.

Innovation Solution

A backlight unit with an optical structure that can be adjusted between 2D and 3D modes using a light source unit capable of emitting collimated or diverging light, and an optical switch to selectively transmit this light, allowing a single light guide plate to output light for either 2D or 3D image display by controlling the exit direction of collimated light through a diffraction device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate backlight units are used for 2D and 3D modes, then the display quality for each mode is optimized, but the device complexity and number of light sources increase

Engineering Contradiction:
Improvedisplay qualityVSAvoidnumber of light sources
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a single backlight unit that can operate in both 2D and 3D modes by using a switchable optical structure. The light source unit emits light that can be directed through different optical paths: in 2D mode, light passes through a first optical structure for uniform illumination, while in 3D mode, light passes through a second optical structure with microlenses to create directional light paths for left and right eyes. This multi-functional design eliminates the need for separate backlight units for each mode.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs a switchable optical structure that can dynamically change its configuration based on the display mode. An optical switch selectively connects the light source unit to either the first optical structure (for 2D) or the second optical structure (for 3D). This dynamic switching capability allows the system to adapt its optical properties in real-time, enabling a single backlight unit to serve multiple functions effectively.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple light sources are used for 2D and 3D modes, then the display performance for each mode is maintained, but the manufacturing cost and assembly complexity increase

Engineering Contradiction:
Improvedisplay performanceVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the functionality of multiple light sources into a single light source unit that serves both 2D and 3D display modes. The first optical structure and second optical structure are integrated into one backlight unit, sharing common components such as the light source, driver circuit, and control logic. This consolidation reduces the number of parts that need to be manufactured and assembled, thereby lowering manufacturing costs and simplifying the production process while maintaining display performance through optimized optical design.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single backlight unit is used for both 2D and 3D modes, then the device complexity is reduced, but the light intensity uniformity and color balance may deteriorate

Engineering Contradiction:
Improvenumber of backlight unitsVSAvoidlight intensity uniformity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The patent applies local quality optimization by designing the second optical structure with an array of microlenses that create localized light paths. Each microlens focuses light in a specific direction to form separate image regions for left and right eyes. The optical switch and optical structures are positioned to ensure uniform light distribution across the display panel. This localized optimization of light paths and intensity distribution maintains high light intensity uniformity and color balance in both 2D and 3D modes despite using a single backlight unit.

Inventive Principle:
Principle #3Local quality

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

Enables a single backlight unit to switch between 2D and 3D modes without the need for separate units, reducing the number of light sources and associated circuits, while maintaining effective light intensity uniformity and color balance for both display modes.

Implementation Method 1

a light source unit configured to emit at least one of collimated light and diverging light

Methodology Applied
Scientific EffectCollimation:

Implementation Method 2

an optical switch configured to selectively transmit the collimated light or the diverging light from the light source unit

Methodology Applied
Scientific EffectLight transmission and direction control: Refraction

Implementation Method 3

a diffraction device configured to adjust a direction in which collimated light is emitted from the light guide plate according to at least one of an angle of incidence of the collimated light on the light guide plate and a wavelength of the collimated light

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3136159B1Backlight unit and 3D image display apparatus
Publication Date: 2020.02.26 SAMSUNG ELECTRONICS CO LTD
  • EP3136159B1 patent drawingFigure 1~3
  • EP3136159B1 patent drawingFigure 4~5
  • EP3136159B1 patent drawingFigure 6~7

AI summary

Provided are a lighting system, a backlight unit and a 3D image display apparatus including the backlight unit. The backlight unit includes: a lighting system configured to selectively output collimated light and diverging light, a diffraction device, and a light guide plate configured to guide the collimated light and the diverging light from the lighting system to the diffraction device. An exit direction of the collimated light from the diffraction device depends on at least one of an angle of incidence of the collimated light and the wavelength of the collimated light.