Backlight Assembly Anti-Peeping Light Guide Plate

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Solution Overview

Problem

Conventional anti-peeping display technologies suffer from reduced brightness and limited viewing angles, making them inadequate for secure information transmission and personal data protection in online transactions and special fields.

Innovation Solution

A backlight assembly with a light guide plate featuring dots with first and second reflecting surfaces, allowing for switching between anti-peeping and normal display modes by directing light in a preset direction for anti-peeping and diffusely reflecting light for wider viewing angles, enhancing both security and brightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a layer with a grating structure is placed in front of the display panel to achieve anti-peeping function, then the security against peeping is improved, but the brightness of the display panel significantly drops

Engineering Contradiction:
Improveanti-peeping securityVSAvoiddisplay brightness
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The display panel is divided into multiple sub-pixels (red, green, blue) with different viewing angle characteristics. Each sub-pixel is independently controlled to achieve anti-peeping effect while maintaining overall brightness through selective activation of appropriate sub-pixels based on viewing direction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sub-pixels are assigned different luminance values and viewing angle properties. The display system adjusts the luminance of each sub-pixel locally according to the detected viewing direction, ensuring that only the appropriate sub-pixels are activated for the current viewing angle, thereby preventing peeping while maintaining brightness for legitimate viewers

Inventive Principle:
Principle #3Local quality

2Reliability

If a layer with a grating structure is placed in front of the display panel to achieve anti-peeping function, then the security against peeping is improved, but the viewing angle of the display panel is limited

Engineering Contradiction:
Improveanti-peeping securityVSAvoidviewing angle
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The display system dynamically adjusts the luminance and activation state of different sub-pixels based on the real-time detected viewing direction. This dynamic adaptation allows the display to maintain wide viewing angle coverage while preventing peeping from unauthorized directions, as the system responds flexibly to changing viewing conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The display panel utilizes multiple sub-pixels with different viewing angle characteristics (red, green, blue sub-pixels having different luminance and angular properties). By combining these different sub-pixel types, the system achieves both wide viewing angle coverage and anti-peeping security in a single display structure

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

3Reliability

If conventional anti-peeping technology is used, then the anti-peeping function is achieved, but the overall display performance and user experience deteriorate

Engineering Contradiction:
Improveanti-peeping functionVSAvoiddisplay performance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The display system incorporates viewing direction detection and uses this feedback to dynamically adjust the luminance and activation state of different sub-pixels. This closed-loop control ensures that the anti-peeping function is achieved while automatically optimizing display performance for legitimate viewing conditions, thereby maintaining good user experience

Inventive Principle:
Principle #23Feedback

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 maintains high brightness and improved viewing angles in anti-peeping mode while enabling normal display functionality, addressing the limitations of conventional technologies.

Implementation Method 1

The first reflecting surface is configured to reflect a first incident light such that reflected light emerges from the light guide plate in a first preset direction

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the second reflecting surface is configured to diffusely reflect a second incident light such that the reflected light emerges dispersedly from the light guide plate

Methodology Applied
Scientific EffectDiffuse reflection: Reflection

Data Source

PatentEP3491465B1Backlight assembly and display apparatus
Publication Date: 2023.04.05 BOE TECHNOLOGY GROUP CO LTD
  • EP3491465B1 patent drawingFigure 1~2
  • EP3491465B1 patent drawingFigure 3~4
  • EP3491465B1 patent drawingFigure 5A~5B

AI summary

A backlight assembly includes a light guide plate (100), containing a plurality of dots (110). Each dot (110) includes a first reflecting surface (111) and a second reflecting surface (112), respectively configured to reflect a first incident light such that reflected light emerges in a first preset direction in a narrow viewing angle mode, and to diffusely reflect a second incident light such that the reflected light emerges dispersedly in a wide viewing angle mode. A first light source(201) can be disposed over a lateral side of the light guide plate (100) and facing the first reflecting surface (111), to provide the first incident light on the first reflecting surface (111) in the narrow viewing angle mode. A second light source (202) can be disposed over another lateral side of the light guide plate (100) and facing the second reflecting surface (112) to provide the second incident light on the second reflecting surface (112) in the wide viewing angle mode.