Reflective Hollow Pedestal LED Source for Narrow Beam Backlighting
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Solution Overview
Problem
LEDs in display systems emit light at wide angles, which may not be collected by the collection optic or are incident at undesirably large angles, leading to inefficiencies in backlighting LCOS and other displays.
Innovation Solution
The use of a hollow pedestal with reflective interior surfaces and a light transmitting optical element to control the radiation pattern, narrowing it to better align with the collection optic, using specularly reflective or light scattering surfaces and optionally incorporating light scattering materials or multiple stacked pedestals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are used to backlight displays, then light emission is achieved, but the radiation pattern is too wide causing light loss
Solution Approach 1:
The patent introduces a hollow pedestal with reflective interior surfaces as an intermediary component between the LED and the collection optic. This pedestal acts as a mediator that redirects wide-angle light emissions toward the collection optic, converting otherwise lost light into useful illumination for the display system.
Solution Approach 2:
The patent modifies the radiation pattern parameters by using reflective surfaces within the hollow pedestal to redirect light at specific angles. This changes the angular distribution of emitted light from a wide pattern to a more directed pattern that matches the collection optic's acceptance angle, thereby improving light collection efficiency.
2Loss of energy
If a hollow pedestal with reflective surfaces is added to narrow the radiation pattern, then light collection efficiency is improved, but device complexity increases
Solution Approach 1:
The hollow pedestal serves multiple functions simultaneously: it provides structural support for the LED, acts as a light redirecting element through its reflective interior surfaces, and defines the spatial geometry for optimal light collection. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
3Loss of energy
If the optical element is placed close to the LEDs, then light collection is improved, but heat management becomes difficult
Solution Approach 1:
The patent segments the light collection function from the heat generation source by using the hollow pedestal as an intermediate structure. The pedestal's reflective surfaces redirect light from the LED toward the collection optic while maintaining physical spacing, thus separating the optical function from the thermal management challenge.
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 provides a narrowed radiation pattern that effectively directs light to the collection optic, improving the efficiency of backlighting in displays.
Implementation Method 1
a hollow pedestal comprising side walls having reflective interior surfaces that define sides of an internal cavity
Data Source
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AI summary
An LED light source comprises a hollow pedestal comprising side walls having reflective interior surfaces that define sides of an internal cavity. An LED mounting surface is disposed within the cavity, with one or more LEDs disposed on the LED mounting surface. A light transmitting optical element is disposed opposite from the mounting surface, spaced apart from the one or more LEDs, and supported by the pedestal side walls. The LED light source provides a narrowed radiation pattern that may, for example, be advantageously employed for backlighting LCOS and other displays.