Flat Panel Illuminator Curved Reflector Light Guide Coupling
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Solution Overview
Problem
Existing edge-lit electronic displays face inefficiencies in light emission coupling into light guides due to losses at the LED/light-guide interface, leading to reduced brightness, increased power consumption, and degraded image quality from stray light effects.
Innovation Solution
A flat-panel illuminator system utilizing a concentrating reflector with a curved reflective portion and an air-filled gap between the light emitters and the light guide, which narrows the light distribution to match the light guide's acceptance angles, reducing propagation losses and bezel size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional LED edge-lit configuration is used, then device simplicity is maintained, but light coupling efficiency is poor leading to reduced brightness and increased power consumption
Solution Approach 1:
A concentrating reflector is introduced as an intermediary optical element between the LED and light guide. The reflector has a specific elliptical geometry with the LED positioned at one focus and the light guide input edge at the other focus, enabling efficient light redirection and coupling while maintaining system simplicity
Solution Approach 2:
The concentrating reflector employs a curved elliptical surface geometry rather than flat surfaces. This curvature is specifically designed to redirect light rays from the LED in a Lambertian distribution pattern into a concentrated beam that matches the light guide's acceptance angle, significantly improving coupling efficiency
2Object-affected harmful factors
If direct LED-to-light guide coupling is used, then device thickness is reduced, but stray light effects degrade display image quality
Solution Approach 1:
The concentrating reflector acts as a mediator that conditions the light before it enters the light guide. By positioning the light guide's input edge at the second focus of the elliptical reflector, the system achieves precise angular control of coupled light, minimizing stray light while maintaining a thin profile
Solution Approach 2:
The reflector design provides localized optical control at the LED-to-light guide interface. The elliptical geometry creates a specific regional light distribution pattern that concentrates light into the light guide's acceptance cone while suppressing stray light in other directions, improving image quality without increasing overall device thickness
3Loss of energy
If large coupling optics are used at light guide input edge, then light coupling efficiency is improved, but bezel width and thickness increase
Solution Approach 1:
The elliptical curved reflector concentrates light into a narrow angular distribution that precisely matches the light guide's acceptance angle. This curved geometry achieves high coupling efficiency without requiring large optical elements, thereby avoiding increased bezel area and thickness
Solution Approach 2:
The system changes the angular distribution parameter of light from a broad Lambertian pattern to a concentrated directional beam through the elliptical reflector geometry. This parameter transformation enables efficient coupling into the light guide while using a compact reflector structure that does not increase bezel dimensions
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 achieves high coupling efficiency by converting most light into a desired elliptical angular range, reducing propagation losses and 'hot spots', and allowing for a thinner bezel, thereby enhancing display brightness and image quality while minimizing power consumption.
Implementation Method 1
a concentrating reflector including a curved reflective portion
Data Source
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AI summary
Examples are disclosed that relate to the coupling of light into a light guide for a backlight system. One disclosed example provides a flat-panel illuminator comprising a concentrating reflector, a light guide, and one or more light emitters. The concentrating reflector includes a curved reflective portion. The light guide includes a planar face and an input edge positioned adjacent the concentrating reflector, and the one or more light emitters are arranged within the concentrating reflector and spaced from the input edge of the light guide.