LED Light Source Device with Polarization Control for HUDs
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Solution Overview
Problem
Existing light source devices for head-up displays (HUD) and ultra-compact projectors lack sufficient light-use efficiency and uniform illumination characteristics, particularly when using LEDs and collimating optics.
Innovation Solution
A light source device comprising a solid-state light source, a collimating optical system, a light guide that redirects light, and a polarization converting element to align polarized light, enhancing light-use efficiency and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional light guide illumination device is used, then the device structure is simple, but the light-use efficiency characteristics and uniform illumination characteristics are insufficient
Solution Approach 1:
A polarization converting element is introduced as an intermediary component between the light source and light guide. This element converts unpolarized LED light into polarized light, which then interacts with the light guide's polarization-maintaining structure to achieve superior light-use efficiency and uniform illumination characteristics
Solution Approach 2:
The patent changes the optical parameters of the system by introducing polarization control. The polarization converting element alters the polarization state of light, and the light guide is designed with specific polarization-maintaining properties, creating a parameter-based optimization that improves both efficiency and uniformity
2Volume of moving object
If the optical system is downsized for compact applications, then the device becomes more compact, but the illumination uniformity and light-use efficiency deteriorate
Solution Approach 1:
By changing the polarization parameter of light and designing the light guide with polarization-maintaining properties, the system achieves superior illumination uniformity in a compact form factor. The polarization control enables precise optical field management that compensates for the reduced size
Solution Approach 2:
The patent employs composite optical structures including polarization converting elements and polarization-maintaining light guides made from specially designed materials. This composite approach enables compact sizing while maintaining high illumination uniformity through the synergistic interaction of different optical components
3Speed
If LED light is converted to collimated light, then the light directionality is improved, but the polarization alignment and uniform illumination are compromised
Solution Approach 1:
The polarization converting element serves as a mediator that reconciles the conflict between collimation and polarization uniformity. It converts LED light into polarized collimated light, ensuring both directionality and polarization alignment are achieved simultaneously
Solution Approach 2:
The system changes multiple optical parameters simultaneously: the collimating optics adjust the directional parameter while the polarization converting element adjusts the polarization parameter. This multi-parameter control achieves both good directionality and polarization uniformity
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 a downsized, highly efficient, and cost-effective light source suitable for HUDs and ultra-compact projectors with improved light-use efficiency and uniform illumination.
Implementation Method 1
a polarization converting element that aligns polarization directions of the light exiting the light guide into one direction
Implementation Method 2
a light guide that allows the light having exited the collimating optical system to enter and allows this light to exit in a direction that differs from a direction of entry
Data Source
AI summary
Provided is a compact light source device that can be manufactured at a low cost and is suitable as an illumination light source for a display device of an electronic device such as an HUD or an ultra-compact projector. This light source device includes a solid-state light source, a collimating optical system that converts light having exited the solid-state light source into a substantially collimated light; and a light guide that allows the light having exited the collimating optical system to enter and allows this light to exit in a direction that differs from a direction of entry. The light source device further includes a polarization converting element that aligns polarization directions of the light exiting the light guide into one direction.