Double-Sided LCD Using Dual Backlights and Segmented Light Guide
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Solution Overview
Problem
Current display technologies, such as LCDs, face challenges in achieving a double-sided transparent display due to bulkiness, high material costs, and reduced transparency when attempting to display images on both sides, requiring multiple panels and backlight units.
Innovation Solution
A display apparatus comprising one liquid crystal display and two backlight units, where each backlight unit has a light guide plate with patterns to enable independent image display on non-overlapping areas on both sides of the liquid crystal layer, allowing for flexible image positioning and attributes-based adjustment, and the use of external light for certain areas to maintain transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two LCD panels, two highly-transparent backlight units and two driving boards are used to accomplish a transparent LCD viewable at both sides, then double-sided viewing capability is achieved, but transparency is lowered and material costs increase
Solution Approach 1:
The patent merges two separate LCD panels into a single LCD panel that can display images on both sides. By using one LCD panel with two backlight units positioned on opposite sides, the structure achieves double-sided viewing capability while reducing material consumption and maintaining transparency.
Solution Approach 2:
A single LCD panel is designed to serve multiple functions: displaying images on the first side when the first backlight unit is active, displaying images on the second side when the second backlight unit is active, and potentially functioning as a transparent window when both backlight units are inactive. This multi-functionality eliminates the need for separate panels for each viewing side.
2Quantity of substance
If a single LCD panel with two backlight units is used for double-sided display, then volume and material costs are reduced, but image display control on specific areas becomes complex
Solution Approach 1:
The LCD panel is divided into different display areas corresponding to each backlight unit. The first backlight unit illuminates a first display area on the first side, while the second backlight unit illuminates a second display area on the second side. This segmentation allows independent control of each side's image display, simplifying the control complexity despite using a single panel.
3Illumination intensity
If backlight units illuminate entire areas for image display, then image visibility is ensured, but transparency in specific areas is reduced
Solution Approach 1:
The backlight units are designed to illuminate specific local areas rather than the entire LCD panel. The first backlight unit illuminates a first display area on the first side, and the second backlight unit illuminates a second display area on the second side. This localized illumination ensures image visibility in display areas while maintaining transparency in non-illuminated areas, allowing the display to function as a transparent window when needed.
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
This configuration reduces volume and material costs while enabling convenient double-sided viewing of different or reversed images, with the ability to display images on specific areas or function as a transparent window, providing a more efficient and cost-effective solution for double-sided displays.
Implementation Method 1
a liquid crystal layer, a first backlight unit arranged at a first side of the liquid crystal layer, and a second backlight unit arranged at a second side opposite the first side of the liquid crystal layer
Implementation Method 2
The first backlight unit may include a first light guide plate and a first light source, and the second backlight unit may include a second light guide plate and a second light source, the first light guide plate may have a pattern disposed on an area corresponding to the first area at the second side of the liquid crystal layer
Data Source
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AI summary
A display device 20 is viewable from two sides and displays first and second images. The display panel comprises a liquid crystal (LC) layer (25, 40) as well as first and second backlight units (21, 41, 28, 42) arranged at a first side (43) and an opposite second side (45) of the LC layer, respectively. Light from the first backlight (21, 41) enters the LC layer at its first side (43) but leaves through a first area (46) on its second side (45) to display the first image, whereas light from the second backlight (28, 42) enters the liquid crystal layer at its second side (45) but leaves through a second area (44) on its first side (43) to display the second image. The second area (44) and the first area (46) do not overlap. The device thus has a smaller volume and is cheaper than conventional double-sided displays.