Bar Collimator Diffractive Coupling for Backlight Illumination
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Solution Overview
Problem
Passive electronic displays, which do not emit light, face limitations in practical applications due to their inability to emit light, necessitating coupling with external light sources to function as active displays.
Innovation Solution
A bar collimator system with a diffraction grating is used to provide a collimated source of illumination to a backlight, allowing passive displays to function as active displays by directing light beams towards the display, enabling the creation of 3D or multiview images without the need for external light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passive displays are coupled with external light sources to enable light emission, then the displays can function as active displays, but the device complexity and requirement for external components increases
Solution Approach 1:
The patent combines the backlight illumination system and the display into a single integrated device. The backlight is embedded within the display structure, eliminating the need for separate external light sources while maintaining the ability to emit light. This merging resolves the contradiction by enabling light emission capability without requiring complex external coupling arrangements.
2Illumination intensity
If conventional backlights are used to illuminate passive displays, then light emission is achieved, but uniformity of illumination is poor and striping artifacts appear
Solution Approach 1:
The patent employs a curved or arched waveguide structure instead of a conventional flat backlight. This curvature enables more uniform light distribution across the display surface by optimizing the optical path and reducing hot spots and striping artifacts. The curved geometry transforms the illumination pattern to achieve superior uniformity while maintaining effective light emission.
3Adaptability or versatility
If external light sources are coupled to passive displays, then light emission is enabled, but the overall size and volume of the display system increases
Solution Approach 1:
The patent implements a nested structure where the backlight is embedded within the display layers. The waveguide is integrated into the display stack, with the light source positioned within or adjacent to the display structure rather than as a separate external component. This nesting approach enables active display functionality while minimizing the overall volume of the display system.
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 system provides uniform, striping-free collimated light to passive displays, enhancing their functionality and usability in applications such as 3D electronic displays by converting light from a light source into a collimated beam for effective illumination.
Implementation Method 1
a diffraction grating disposed on a side of the light guide. According to various embodiments, the diffraction grating is configured to diffractively couple out a portion of the guided light and to direct the coupled-out portion toward an input of a backlight as a substantially collimated beam of light
Data Source
AI summary
A bar collimator and a backlight system employ diffractive coupling to provide a collimated source of illumination to a backlight. The bar collimator includes a light guide and a diffraction grating disposed on a side of the light guide. The light guide is configured to guide light received from a light source as guided light. The diffraction grating is configured to diffractively couple out a portion of the guided light and to direct the diffractively coupled-out portion toward an input of a backlight as a collimated light having an extent corresponding to a length of the backlight input. A backlight system includes the bar collimator and further includes a light source and a backlight adjacent to the light guide of the bar collimator, the backlight being configured to receive collimated light from a diffraction grating of the bar collimator.