Light Guide Plate Incident Slits for Field Sequential Display Mixing
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Solution Overview
Problem
In liquid crystal display devices using the field sequential method with single color LEDs, there is a limitation in the area that can be used for white light creation due to insufficient mixing of red, green, and blue lights, resulting in non-display areas that reduce the effective display area.
Innovation Solution
The design incorporates a light guide plate with a concave portion housing an LED set where a symmetrical arc-shaped incident slit is used for the central LED and asymmetrical saw tooth slits for the side LEDs, optimizing light distribution angles to enhance mixing and increase the white light creation area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional light guide plate with LEDs mounted on the side is used, then the device structure is simple, but the area that can be used as an area light source is limited due to great light intensity variation around the LED locations
Solution Approach 1:
The light guide plate is divided into multiple light guide parts, each with its own convex portion and LED mounting area. This segmentation allows each part to independently manage light distribution, reducing overall light intensity variation across the entire plate while expanding the usable area light source region.
Solution Approach 2:
Each light guide part has a convex portion with specific optical properties tailored to that location. The convex portions create localized light distribution characteristics that optimize illumination in different regions, allowing the light guide plate to provide uniform area light source coverage across the entire display surface.
2Loss of energy
If white LED is used as the light source, then color variation problem is avoided, but energy efficiency is low because color filters block two-thirds of the light energy
Solution Approach 1:
The display device uses field sequential driving method, sequentially activating red, green, and blue LEDs in different time periods. This periodic action allows each LED type to emit its full energy without color filter blocking, achieving high energy efficiency while the rapid sequential switching prevents color variation through persistence of vision.
Solution Approach 2:
The system changes the temporal parameter of LED activation by using field sequential driving with different time periods for each color LED. This parameter change allows the LEDs to operate without color filters, maximizing energy efficiency while maintaining color accuracy through time-based control.
3Area of stationary object
If a large number of LED sets with three color LEDs arranged in delta pattern are used, then white area light source is obtained, but the mixing distance required is long which reduces the effective display area
Solution Approach 1:
The patent introduces a vertical dimension by creating convex portions that protrude from the light guide plate surface. This dimensional change allows LEDs to be mounted on the convex portions, positioning them closer to the display surface and reducing the horizontal mixing distance required for effective color blending across the display area.
Solution Approach 2:
The convex portions have curved surfaces that help distribute and mix light from the mounted LEDs more efficiently. The curvature of the convex portions facilitates light reflection and mixing, reducing the distance required for complete color mixing while expanding the effective display area.
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 effectively increases the display area while maintaining the overall device size, improving light mixing and energy efficiency by reducing non-display areas and optimizing luminous efficiency.
Implementation Method 1
Incident slits with symmetrical shapes are formed in the concave portion of the light guide plate... saw tooth slits with asymmetrical shapes are formed in the concave portion of the light guide plate... optimizing light distribution angles to enhance mixing
Data Source
AI summary
A display device includes a side light type backlight for white color display by single color LEDs, an LED set is placed in a concave portion of a light guide plate, in which a first color LED is located in the center and a second or third color LED is located on the side of the first color LED. An incident slit with an arc shaped convex portion is formed facing the first color LED, and a saw tooth slit with a right-angled triangular concave portion is formed facing the second or third color LED. This allows directing the distribution axes of the lights from the second and third color LEDs to the center side, and adjusting orientation angles to allow effective mixing of the three color lights, in order to increase the white color area and effective display area.