Multiscopic Display Backlight With Cavity Reflectors for High Brightness
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Solution Overview
Problem
Conventional liquid crystal display (LCD) based heads-up displays (HUDs) struggle to achieve sufficient brightness levels for autostereoscopic and multiscopic displays, especially in bright outdoor conditions, leading to reduced usability and eyestrain due to low brightness levels.
Innovation Solution
A backlight unit with an array of light-emitting elements surrounded by cavity reflectors and a collimator, along with additional components like a transparent diffuser, brightness enhancement film, and reflecting polarizers, to maximize light utilization and enhance brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional edge-lit backlight unit is used in an LCD based HUD, then the device complexity is kept low, but the brightness level is insufficient for bright outdoor conditions
Solution Approach 1:
The backlight unit is divided into multiple light-emitting elements (edge-lit LEDs and area-lit OLEDs) arranged in specific patterns. This segmentation allows different regions to contribute differently to the overall brightness, enabling high brightness levels while maintaining reasonable device complexity through modular design.
Solution Approach 2:
The patent combines edge-lit LED technology with area-lit OLED technology in a single backlight unit. This merging of different light-emitting technologies allows the system to achieve high brightness levels suitable for bright outdoor conditions while managing device complexity through integrated design.
2Adaptability or versatility
If the field of view area is increased to provide wider viewing angles, then the adaptability is improved, but the brightness level decreases due to limited photo-emitting cells
Solution Approach 1:
The backlight unit is segmented into edge-lit regions and area-lit regions, allowing different portions of the display area to receive adequate light even when the overall field of view is large. This segmentation ensures that brightness is maintained across the entire viewing area.
Solution Approach 2:
The patent transitions from traditional 2D backlight illumination to a more distributed 3D arrangement of light-emitting elements. By placing LEDs at edges and OLEDs in specific areas throughout the backlight unit, light is distributed more effectively across the entire display area, maintaining brightness even with large field of view dimensions.
3Adaptability or versatility
If multiscopic optical elements are added to create autostereoscopic effect, then the adaptability for 3D display is improved, but the brightness level is further reduced
Solution Approach 1:
The backlight unit performs preliminary light generation and distribution before light reaches the multiscopic optical elements. By pre-distributing light from multiple LEDs and OLEDs across the display area, the system ensures that sufficient brightness is available even after light is redirected by the autostereoscopic elements.
Solution Approach 2:
The patent merges multiple light-emitting technologies (edge-lit LEDs and area-lit OLEDs) to create a comprehensive illumination system that works in conjunction with multiscopic optical elements. This combination ensures adequate brightness levels are maintained while enabling autostereoscopic functionality.
4Illumination intensity
If the number of photo-emitting cells is limited, then the device complexity is kept manageable, but the brightness level becomes insufficient for large display areas
Solution Approach 1:
The backlight unit is segmented into edge-lit LED regions and area-lit OLED regions, allowing light to be distributed efficiently across the entire display area. This segmentation enables high brightness levels without requiring an excessive number of light-emitting elements throughout the entire backlight.
Solution Approach 2:
Different regions of the backlight unit have different light-emitting characteristics - edge-lit LEDs provide concentrated light at boundaries while area-lit OLEDs provide distributed light across specific regions. This local quality variation optimizes brightness distribution across the display area while managing the total number of light-emitting elements.
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 enables high brightness levels suitable for autostereoscopic and multiscopic displays, allowing legible image projection in various lighting conditions, including bright outdoor environments, with reduced light wastage and improved usability.
Implementation Method 1
an array of light-emitting elements; a plurality of cavity reflectors, wherein a given cavity reflector partially surrounds a corresponding light-emitting element of said array
Implementation Method 2
a collimator arranged on an optical path of the array of light-emitting elements
Implementation Method 3
a plurality of cavity reflectors, wherein a given cavity reflector partially surrounds a corresponding light-emitting element of said array
Data Source
AI summary
A backlight unit for a liquid crystal display device is disclosed. The backlight unit includes an array of light-emitting elements and a plurality of cavity reflectors, wherein a given cavity reflector partially surrounds a corresponding light-emitting element of said array. The backlight unit further includes a collimator arranged on an optical path of the array of light-emitting elements, a first drive circuit that is employed to individually control the light-emitting elements of said array, and a controller. The controller is configured to generate or receive drive signals for controlling the light-emitting elements of said array, and send the drive signals to the first drive circuit.