Switchable Backlight Module for Privacy and Wide Viewing
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Solution Overview
Problem
Conventional display devices achieve anti-peeping effects by using anti-peeping films that impair display quality and brightness, and require increased light source power to compensate, while failing to provide localized privacy control.
Innovation Solution
A backlight module with a switching control unit, first and second light source units, and prism films that allow switching between privacy and share modes by controlling light output ranges through activation and deactivation of light sources and prism films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If anti-peeping film is installed to filter out lights of larger angles, then anti-peeping effect is achieved, but display quality and brightness are impaired
Solution Approach 1:
The patent employs a switching control unit that can dynamically switch between different light source units (first light source unit with first light guide and first prism film for privacy mode, second light source unit with second light guide for share mode). This dynamic switching allows the system to adapt its light output characteristics based on operational requirements, providing narrow viewing angle for privacy or wide viewing angle for sharing without using anti-peeping films.
Solution Approach 2:
The backlight module is segmented into multiple independent light source units, each with its own light guide and optical components. The first light source unit includes a first light guide and first prism film, while the second light source unit includes a second light guide. This segmentation allows independent control of each light source's output characteristics, enabling selective activation for different viewing angle requirements without compromising overall display quality.
2Object-affected harmful factors
If anti-peeping film is installed to filter out lights of larger angles, then anti-peeping effect is achieved, but light source power output must be increased to compensate for brightness loss
Solution Approach 1:
The switching control unit dynamically selects which light source unit to activate based on the operational mode. In privacy mode, only the first light source unit is activated with its light guided through the first prism film to create narrow viewing angle. In share mode, the second light source unit is activated with the second light guide for wide viewing angle. This dynamic selection avoids the need to increase overall power output to compensate for film absorption.
Solution Approach 2:
The patent extracts the anti-peeping function from the anti-peeping film and relocates it to the optical path control mechanism. By using the first light guide and first prism film to guide and direct light, the system achieves the anti-peeping effect through optical path control rather than filtration, eliminating the need for additional power compensation that would be required if using anti-peeping films.
3Object-affected harmful factors
If anti-peeping film is used to filter light angles, then privacy protection is achieved, but localized anti-peeping effect cannot be satisfied
Solution Approach 1:
The switching control unit is divided into multiple modulation regions, each capable of independent control. The first modulation region controls the first light source unit and first prism film, while the second modulation region controls the second light source unit. This segmentation enables localized control of privacy protection in different areas of the display, allowing selective activation of privacy mode in specific regions without affecting the entire display.
Solution Approach 2:
Different regions of the backlight module are assigned different optical characteristics. The first light source unit with first light guide and first prism film provides narrow viewing angle for privacy in its region, while the second light source unit with second light guide provides wide viewing angle in its region. This local differentiation allows the system to provide privacy protection only where needed without compromising overall display 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
The backlight module provides uniform brightness-angle distribution in share mode for improved power efficiency and concentrated brightness-angle distribution in privacy mode for enhanced anti-peeping, with localized control options.
Implementation Method 1
the switching control unit is activated to modulate light passing the first prism film from the first light source unit
Implementation Method 2
a first prism film, wherein the first light source unit is disposed below the switching control unit and includes a first light source and a first light guide; the first prism film is disposed at a light exit side of the first light guide
Implementation Method 3
the second light source unit is disposed between the switching control unit and the first light source unit and includes a second light source and a second light guide
Data Source
AI summary
A backlight module includes a switching control unit, a first light source unit disposed below the switching control unit and including a first light source and a first light guide, a second light source unit disposed between the switching control unit and the first light source unit and including a second light source and a second light guide, and a first prism film disposed at a light exit side of the first light guide. In a privacy mode, the second light source is turned off, the first light source is turned on, and the switching control unit modulates light passing the first prism film, so the backlight module has a first light output range. In a share mode, the second light source is turned on, and the switching control unit is deactivated, so the backlight module has a second light output range larger than the first light output range.