HUD Polarization Control for Ghost-Free Wide-Angle Viewing
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Solution Overview
Problem
Conventional HUD systems suffer from ghost images and limited image quality due to the use of homogeneous polarization, which results in significant ghost image ratios and restricted viewing angles, especially at the edges of the projected image.
Innovation Solution
A HUD system with a polarizing element that sets the polarization state of each light beam based on its direction, using a polarization-dependent reflection layer, anti-reflection layer, or optical birefringent layer to minimize the ghost image ratio by optimizing the polarization state for each light beam according to its angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If homogeneous polarization is used in HUD systems, then the system structure is simple, but ghost image ratio increases and viewing angle is limited
Solution Approach 1:
The patent applies local quality by making the polarization state spatially varying across the light beam profile. Different regions of the light beam (center vs. edges) have different polarization states optimized for their respective angles of incidence. This is achieved through position-dependent polarization control in the SLM or through spatially varying retardation layers, allowing each region to minimize ghost images locally while maintaining overall system simplicity.
Solution Approach 2:
The patent employs dynamics by making the polarization state adjustable and adaptable rather than fixed. The SLM can dynamically modify polarization states in real-time based on the angle of incidence for different light beam regions. This dynamic control allows the system to optimize polarization for each spatial location, reducing ghost images across the entire viewing angle range while maintaining structural simplicity.
2Device complexity
If homogeneous polarization is used in HUD systems, then the device structure is simple, but viewing angle is restricted
Solution Approach 1:
The patent applies local quality by making the polarization state spatially varying across the light beam profile. Different regions of the light beam (center vs. edges) have different polarization states optimized for their respective angles of incidence. This is achieved through position-dependent polarization control in the SLM or through spatially varying retardation layers, allowing each region to minimize ghost images locally while maintaining overall system simplicity.
Solution Approach 2:
The patent employs dynamics by making the polarization state adjustable and adaptable rather than fixed. The SLM can dynamically modify polarization states in real-time based on the angle of incidence for different light beam regions. This dynamic control allows the system to optimize polarization for each spatial location, reducing ghost images across the entire viewing angle range while maintaining structural simplicity.
3Object-affected harmful factors
If polarization state is optimized for each light beam direction, then ghost image ratio is minimized, but device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a SLM or spatially varying optical layers as a mediation element between the light source and the windscreen. This intermediary device controls polarization states in a programmable and flexible manner, allowing optimization for each light beam direction without requiring complex mechanical or optical assemblies. The SLM acts as a software-controlled intermediary that simplifies the overall system architecture while achieving the desired polarization control.
4Adaptability or versatility
If polarization state is optimized for each light beam direction, then viewing angle is expanded, but device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a SLM or spatially varying optical layers as a mediation element between the light source and the windscreen. This intermediary device controls polarization states in a programmable and flexible manner, allowing optimization for each light beam direction without requiring complex mechanical or optical assemblies. The SLM acts as a software-controlled intermediary that simplifies the overall system architecture while achieving the desired polarization control.
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
Significantly reduces the ghost image ratio and expands the area considered ghost image-free, allowing for improved image quality and larger viewing angles, compatible with existing systems and enabling augmented reality experiences.
Implementation Method 1
a polarizing element is provided in the light path between the image display device and the reflecting element for setting a polarization state of each of the incident light beams
Implementation Method 2
the reflecting element is arranged relative to the image display device such that a portion of the incident light beams reflected in the direction of the design detection point reaches the first reflective surface at a Brewster angle
Implementation Method 3
A layer selected from a group consisting of a polarization-dependent reflection layer, an anti-reflection layer, or an optical birefringent layer is provided on the first reflective surface
Implementation Method 4
A layer selected from a group consisting of a polarization-dependent reflection layer, an anti-reflection layer, or an optical birefringent layer is provided on the first reflective surface
Implementation Method 5
A layer selected from a group consisting of a polarization-dependent reflection layer, an anti-reflection layer, or an optical birefringent layer is provided on the first reflective surface
Data Source
AI summary
A head-up display (HUD) system wherein an individually optimized polarization state is provided for each incident beam from an image display device.