Curved Optical Element for LCD Backlight Collimation
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Solution Overview
Problem
Current LCD backlight systems face challenges in achieving the required collimation of light due to the large divergence angle of the light source, leading to reduced color saturation and energy efficiency, as conventional LED packaging techniques fail to meet the collimation needs.
Innovation Solution
A directional light distributing optical element with a light incident surface and a light emission curved surface, featuring a first curve with multiple tangent points, is designed to collimate light, ensuring the included angle between the light axis and optic axis is between −15° and 15°, and the light emission surface is optimized to reduce volume and improve alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional LED packaging techniques are used, then the device complexity is reduced and ease of manufacture is improved, but the collimation requirement of the backlight source cannot be met
Solution Approach 1:
The patent employs a curved light emission surface with specific radius of curvature to achieve collimation of light from LED sources. The curved geometry transforms divergent spherical light waves into parallel beams, meeting the collimation requirement while maintaining compatibility with conventional LED packaging and manufacturing processes
Solution Approach 2:
The patent optimizes specific parameters including the radius of curvature of the light emission surface, the position of the LED source relative to the curved surface, and the refractive index matching between materials. By adjusting these parameters, the system achieves effective collimation using standard manufacturing techniques without requiring complex precision alignment
2Illumination intensity
If a light source with large divergence angle is used, then the ease of operation is improved and the device can be simpler, but the color saturation is greatly reduced due to cross-talk
Solution Approach 1:
The curved optical element acts as an intermediary between the LED light source and the liquid crystal display panel. It transforms the divergent light from the LED into collimated light, ensuring that each subpixel receives light only from its corresponding LED, thereby eliminating cross-talk and maintaining high color saturation while allowing the use of simple high-divergence LED sources
3Illumination intensity
If the backlight source is kept approximately parallel in one dimension and dispersed in another dimension at 90°, then the color saturation is improved, but the device complexity increases
Solution Approach 1:
The curved optical element is designed with different functional zones: one dimension has a curved profile for collimation, while the other dimension remains linear for dispersion. This segmentation of optical functions within a single integrated component achieves the required parallel-in-one-dimension and dispersed-in-another-dimension light distribution without increasing overall system complexity
Solution Approach 2:
The single curved optical element performs multiple functions simultaneously: it collimates light in the vertical dimension while dispersing it in the horizontal dimension, and also serves as a light guide and uniformity distributor. This multi-functionality in one component avoids the need for multiple separate optical elements, keeping the system simple
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 achieves one-dimensional directional light emission, enhancing light collimation and uniformity, suitable for LCDs and other display technologies like 3D and dual-view displays, while reducing the size of the optical element and improving alignment accuracy.
Implementation Method 1
After passing each first tangent point along a connecting line of a light source and each first tangent point, the light exits along a first axis. The included angle formed between the first axis and the optic axis is greater than −15° and smaller than 15°
Data Source
AI summary
A directional light distributing optical element includes a light incident surface and a light emission curved surface. The light incident surface receives a light emitted by a light source. The light emission curved surface and a first plane are intersected to form a first curve. The first curve has a plurality of first curve segments, and each first curve segment includes at least three first tangent points. After passing each first tangent point along a connecting line of the light source and each first tangent point, the light exits along a first axis, and an included angle formed between the first axis and an optic axis is greater than −15° and smaller than 15°. Thus, the light after passing the directional light distributing optical element forms a one-dimensional directional light.