Light Guide Plate Optical Elements for Diagonal Brightness Uniformity
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Solution Overview
Problem
Liquid crystal display devices experience brightness unevenness when viewed diagonally due to the inherent nature of point light sources used in spread illuminating apparatuses, which affects the uniformity of illumination.
Innovation Solution
Incorporating a light guide plate with linearly formed optical elements that have concave/convex shaped parts aligned in a longitudinal direction, extending from the light sources, to modify and diffuse the light path, thereby reducing wasteful emission and enhancing light distribution uniformly across the emitting surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If point light sources (LEDs) are used to illuminate the light guide plate, then the spread illuminating apparatus can be made thin and power consumption is reduced, but brightness unevenness occurs when viewed diagonally
Solution Approach 1:
Optical elements are introduced as intermediary components between the point light sources and the light guide plate. These optical elements have concave/convex shaped parts that modify the light paths, acting as mediators to redistribute light and reduce brightness unevenness when viewed diagonally, while maintaining the thin-profile advantage of LED-based illumination.
Solution Approach 2:
The optical elements change the geometric parameters of light propagation by incorporating concave/convex shaped parts. These shape modifications alter the light paths and emission angles, transforming the direct light from point sources into a more uniformly distributed pattern when viewed from diagonal directions.
2Illumination intensity
If optical elements with concave/convex shaped parts are added to the light guide plate, then brightness unevenness is reduced when viewed diagonally, but the device structure becomes more complex
Solution Approach 1:
The optical elements are positioned in specific regions of the light guide plate where brightness unevenness occurs when viewed diagonally. The concave/convex shaped parts are strategically designed to locally modify light paths in these critical areas, achieving brightness uniformity improvement without requiring complex modifications throughout the entire device structure.
3Ease of manufacture
If the light guide plate uses a simple structure without additional optical elements, then the device is easier to manufacture, but brightness spots and hot spots occur on the emitting surface
Solution Approach 1:
The optical elements incorporate concave/convex curved surfaces instead of flat geometries. These curved surfaces effectively scatter and redistribute light paths, preventing the formation of brightness spots and hot spots on the emitting surface. The curvature design achieves brightness uniformity improvement while maintaining relatively simple manufacturing processes suitable for mass production.
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 effectively reduces brightness unevenness when diagonally viewing the spread illuminating apparatus by diffusing light in a controlled manner, improving light utilization and maintaining high-quality visibility.
Implementation Method 1
an optical path of light that enters from the incident light surface of the light guide plate is modified by the concave/convex shaped parts that constitute the optical elements while the light is progressing through the inside of the light guide plate
Implementation Method 2
the light is guided toward the longitudinal direction of the optical elements. Furthermore, in the course over which the light is guided and the region to which the light is guided, the light is suitably diffused
Data Source
AI summary
Light that enters from an incident light surface of a light guide plate includes not only light which is guided toward the forward direction in front but also light whose optical path is modified by optical elements while progressing through the inside of the light guide plate, and thus wasteful emission from an emitting surface is inhibited. Lights are guided in a longitudinal direction of the optical elements. Light is diffused in the course over which the lights are guided and the region to which they are guided. The lights are guided by the optical elements in the longitudinal direction of the optical elements, and thereby light diffusivity is exhibited in the region in which the optical elements are provided while controlling the directivity of the light.