Multiscopic Display with Adaptive Collimated-Diffused Backlight
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Solution Overview
Problem
Existing autostereoscopic displays face challenges in maintaining stereoscopic effects when viewers move outside the narrow viewing zone due to the use of collimated light sources, leading to loss of brightness and image degradation at extreme angles.
Innovation Solution
A display system with a controllable backlight unit that selectively produces collimated, diffused, or combined light rays based on user eye locations, expanding the viewing zone to ensure clear and accurate virtual image presentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a collimated or near-collimated light source is used for the backlight unit, then the effective brightness is increased, but the viewing zone becomes narrow and extreme viewing angles result in loss of stereoscopic effect
Solution Approach 1:
The patent applies dynamics by making the backlight unit controllable and switchable between different light ray modes (collimated, diffused, or combined) based on viewer position. The system dynamically adjusts the light distribution characteristics to maintain optimal viewing conditions whether the viewer is within or outside the narrow light cone, thereby resolving the contradiction between high brightness and wide viewing adaptability.
Solution Approach 2:
The patent changes the optical parameters of the backlight unit by selectively producing collimated light rays for narrow-angle brightness enhancement or diffused light rays for wide-angle coverage. This parameter switching allows the system to adapt to different viewing scenarios, resolving the contradiction between concentrated brightness and broad viewing zone coverage.
2Adaptability or versatility
If the backlight unit diffuses light over a broad range to achieve wide viewing angles, then the viewing zone is expanded, but the effective brightness decreases
Solution Approach 1:
The system dynamically switches between diffused light mode for wide viewing zone coverage and collimated light mode for high brightness, depending on real-time viewer position detection. This dynamic adaptation allows the system to optimize both viewing zone breadth and brightness intensity rather than being constrained to a fixed light distribution pattern.
Solution Approach 2:
The backlight unit changes its light distribution parameter from diffused to collimated based on viewing conditions. When viewers are outside the narrow light cone, the system switches to diffused mode to expand coverage, and when viewers are within the cone, it switches to collimated mode to maximize brightness, thus resolving the brightness-viewing zone trade-off.
3Adaptability or versatility
If multiscopic optical elements are used to focus light towards specific areas, then the viewing zone is improved, but extreme viewing angles still result in image degradation
Solution Approach 1:
The system performs preliminary action by proactively switching the backlight mode before the viewer reaches extreme angles. When the eye tracking system detects that a viewer is moving toward or is outside the narrow light cone, the backlight unit preemptively switches to diffused mode to ensure continuous high-quality stereoscopic effect, preventing image degradation before it occurs.
Solution Approach 2:
The system uses feedback from the eye tracking system to continuously monitor viewer position and adjust the backlight light distribution accordingly. This closed-loop feedback mechanism ensures that the backlight mode (collimated or diffused) is continuously optimized based on actual viewing conditions, maintaining reliable image quality 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 system dynamically adjusts light output to maintain high-quality stereoscopic effects even when viewers are outside the typical viewing zone, ensuring clear and accurate image perception with minimal hardware complexity.
Implementation Method 1
directing the light into a narrow cone shape, such as a 30-degree angle cone, for example, using reflectors behind the backlight unit
Implementation Method 2
the backlight unit must diffuse light over a broad range, often up to a 180-degree field of view
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3A~3B
AI summary
Information indicative of a relative location of a first eye (110a, 310a, 312a, 318a, 324a, 330a) and of a second eye (110b, 310b, 312b, 318b, 324b, 330b) of an individual one of user(s) is obtained. A light field image is generated or retrieved. The light field image is displayed via a liquid crystal display device (102) for presenting virtual object(s). All the aforementioned steps are repeated for a given time period. During the given time period, it is detected when the first eye and/or the second eye lies outside a current viewing zone of a display system (100, 300). When it happens, a given first region of a controllable backlight unit (CBLU) (106, 200a-c, 308) is determined for presenting the virtual object(s) to the first eye, and a given second region of the CBLU is determined for presenting the virtual object(s) to the second eye. The given first region and the given second region are selectively controlled to produce and direct any one of: diffused light rays (218, 306a-b, 312, 316, 322a-b, 326a-b, 332), a combination of collimated light rays (216, 304a-c, 320, 328, 334) and the diffused light rays, towards the first eye and the second eye, respectively.