Switchable Diffuser Film for Dynamic Viewing Angle Control
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Solution Overview
Problem
Conventional liquid crystal displays have a fixed viewing angle, making it difficult to adjust or reduce the viewing angle without using external privacy filters that introduce unwanted reflections and glare, and are often costly and unwieldy.
Innovation Solution
An electronic device display with a configurable backlight unit that includes a switchable layer or microarray structure, allowing the display to operate in different modes such as privacy, outdoor, and power saving modes by altering the light direction or scattering, thereby adjusting the viewing angle and brightness without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If external privacy filters are used to reduce viewing angle, then privacy is improved, but reflections and glare are introduced
Solution Approach 1:
The patent extracts the privacy control function from external filters and integrates it into the display's backlight unit. The switchable diffuser film is embedded within the display structure, allowing viewing angle control without adding external layers that cause reflections. This internal integration eliminates the harmful reflective properties of external privacy filters while maintaining the desired viewing angle restriction.
Solution Approach 2:
The switchable diffuser film acts as an intermediary element within the backlight unit that controls light distribution. By positioning this film between the light source and the display layers, it mediates the light path to achieve viewing angle control without requiring external filters. This intermediary approach allows precise control of light scattering while avoiding the reflective issues associated with external attachments.
2Object-affected harmful factors
If external privacy filters are used to adjust viewing angle, then privacy is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the privacy control function with the existing backlight unit structure. The switchable diffuser film is integrated into the backlight assembly, combining multiple functions (light generation, light distribution, and viewing angle control) into a single unified system. This eliminates the need for separate external privacy filters and their associated mounting and maintenance complexities.
Solution Approach 2:
The backlight unit is designed to serve multiple functions: it provides illumination, controls viewing angle, and enables different display modes (normal, privacy, outdoor, power saving). The switchable diffuser film is a universal component that contributes to multiple display modes simultaneously, reducing overall device complexity by eliminating the need for separate privacy filter systems.
3Illumination intensity
If backlight intensity is increased for outdoor viewing, then visibility is improved, but power consumption increases
Solution Approach 1:
The patent applies local quality by directing light preferentially in specific directions rather than uniformly in all directions. The switchable diffuser film creates a concentrated beam of light focused on the on-axis viewing direction, which is particularly useful for outdoor viewing. This localized light distribution achieves high on-axis luminance without requiring proportional increases in overall backlight power consumption.
Solution Approach 2:
The patent implements dynamic control of light distribution through the switchable diffuser film. The system can dynamically switch between different display modes (normal, outdoor, power saving) by altering the light scattering properties of the diffuser film. This dynamic adjustment allows the display to optimize luminance distribution in real-time, providing enhanced on-axis brightness for outdoor viewing without proportionally increasing power consumption across all viewing angles.
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 display can adjust its viewing angle and brightness to suit different usage scenarios, providing improved privacy, enhanced visibility in bright conditions, and reduced power consumption, while eliminating the need for external filters.
Implementation Method 1
a switchable diffuser film that receives the collimated backlight from the turning film and that is configured to selectively alter the collimated backlight. The switchable diffuser film is operable in a first state that passes through the collimated backlight to the display layers and is also operable in a second state that scatters the collimated backlight.
Implementation Method 2
a turning film for collimating the backlight output from the light guide plate
Implementation Method 3
a light guide plate that receives the light from the light source and that outputs backlight towards the display layers
Data Source
AI summary
An electronic device may generate content that is to be displayed on a display. The display may have an array of liquid crystal display pixels for displaying image frames of the content. The display may be operated in at least a normal viewing mode, a privacy mode, an outdoor viewing mode, and a power saving mode. The different view modes may exhibit different viewing angles. In one configuration, the display may include a backlight unit that generates a collimated light source and that includes a switchable diffuser film for selectively scattering the collimated light source depending on the current viewing mode of the display. In another configuration, the display may include a backlight unit that generates a scattered light source that includes a switchable microarray structure such as a switchable mirror structure or a tunable microlens array for selectively collimating the scattered light source depending on the current viewing mode.