Light Guide Reflector Switching for Bright Display Glare Control
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Solution Overview
Problem
Light guide displays struggle to function effectively in bright ambient light due to glare from reflections on the light guide and other surfaces, which degrades image quality.
Innovation Solution
An apparatus comprising a light guide, a light reflector, and a combiner, with reflection control means to alternately enable and disable reflection from the light reflector, synchronized with the light engine's duty cycle to reduce glare and enhance image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light reflector is used to enhance image brightness, then the image brightness is improved, but glare from ambient light reflection increases
Solution Approach 1:
The light reflector is activated periodically in synchronization with the light engine's duty cycle. During active periods when the light engine projects images, the reflector is enabled to enhance image brightness. During inactive periods, the reflector is disabled to prevent glare from ambient light. This periodic activation resolves the contradiction by making the reflector's contribution conditional on the presence of useful light.
Solution Approach 2:
The system transitions from a static reflector configuration to a dynamic one where the reflector's optical properties can change state. The reflector is controlled to switch between reflective and non-reflective states, allowing the system to adapt its behavior based on operational conditions. This dynamic control enables the system to optimize image brightness when needed while minimizing glare when the light engine is not active.
2Illumination intensity
If the light reflector is continuously active to maintain image brightness, then image quality is improved, but energy consumption increases
Solution Approach 1:
The light reflector operates periodically rather than continuously, synchronized with the light engine's duty cycle. The reflector is only activated during periods when the light engine is projecting images, and remains inactive during periods when no images are being projected. This periodic operation maintains image brightness when needed while significantly reducing overall energy consumption compared to continuous operation.
3Illumination intensity
If the light reflector is used to enhance image brightness, then the image quality is improved, but the device complexity increases
Solution Approach 1:
The light reflector serves multiple functions within the same optical path: it enhances image brightness during active periods and can be controlled to minimize glare during inactive periods. By integrating the reflector control into the existing light engine duty cycle synchronization, the system achieves enhanced functionality without requiring separate dedicated systems for brightness enhancement and glare reduction, thereby limiting the increase in device complexity.
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 significantly reduces distracting glare while maintaining image brightness, improving the overall quality of the displayed image in bright ambient conditions.
Implementation Method 1
out-coupling diffractive means configured to out-couple light defining the image
Implementation Method 2
the at least one light reflector is configured to reflect at least some of the image to the user
Implementation Method 3
combiner configured to combine the image provided by the light guide and the reflected image provided by the light reflector
Implementation Method 4
polarization control means configured to alternately change a polarization state of light
Data Source
Figure 1~2
Figure 3A~3B
Figure 4(i)~4(iv)
AI summary
An apparatus comprising: at least one light reflector; a light guide configured to provide a received image to a user and also to the at least one light reflector, wherein the at least one light reflector is configured to reflect at least some of the image to the user; and reflection control means for alternately enabling and disabling reflection of light from at least the at least one light reflector.