Polarized HUD Light Guide Layout for Double-Image Reduction
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Solution Overview
Problem
Existing in-vehicle information display systems face issues with low light utilization efficiency, high power consumption, susceptibility to sunlight damage, large volume, and limited flexibility in installation and maintenance, along with challenges in achieving high resolution and reducing double images due to window glass reflections.
Innovation Solution
A configuration using a point or planar light source, optical means to reduce light divergence, and a light guide with specific polarization and reflection surfaces to control light propagation, combined with a retardation plate in the window glass to reduce double images and sunlight damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional HUD system is used to display images through window glass, then the virtual image is formed, but double images appear due to reflections from both inner and outer surfaces of the glass
Solution Approach 1:
A polarizing plate is introduced as an intermediary component between the light guide and the window glass. This polarizing plate selectively transmits light with specific polarization directions while blocking other polarization directions, thereby eliminating the double image effect caused by reflections from both glass surfaces. The polarizing plate acts as a mediator that allows the desired light to pass through while filtering out the harmful reflected light.
2Productivity
If projection-type information display systems are used, then images can be displayed, but light utilization efficiency is low and power consumption is high
Solution Approach 1:
The invention changes the polarization state parameter of light by using a polarizing plate and waveplate combination. By controlling the polarization direction of light, the system optimizes light transmission efficiency and reduces unnecessary light absorption, thereby improving overall light utilization efficiency and reducing power consumption of the light source.
Solution Approach 2:
The invention replaces conventional projection optical systems with a light guide-based direct-view display system. This substitution eliminates complex projection optics and reduces the number of optical components, leading to improved light utilization efficiency and lower power consumption while maintaining image display functionality.
3Ease of operation
If conventional HUD apparatus is installed, then image display is achieved, but the set volume is large and cannot be arranged in the space between steering wheel and window glass
Solution Approach 1:
The invention extracts and removes unnecessary components from the conventional HUD system, such as complex projection optics and intermediate optical elements. By keeping only the essential components (light guide, polarizing plate, waveplate), the system volume is dramatically reduced, enabling installation in the limited space between the steering wheel and window glass.
Solution Approach 2:
The invention uses thin-film optical components such as polarizing plates and waveplates that can be integrated into the light guide structure. These thin-film components replace bulky optical elements, enabling the HUD apparatus to be compact and flexible enough for installation in constrained vehicle interior spaces.
4Measurement precision
If existing HUD system is used, then basic image display is achieved, but resolution is limited to about 80 dots per viewing angle of 1 degree
Solution Approach 1:
The invention uses a light guide that replicates and distributes light from a compact light source across a larger area while maintaining high resolution. The light guide structure acts as a copying mechanism that preserves fine detail information, enabling high-resolution display without requiring proportionally large or complex hardware configurations.
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
Achieves a thin, high-luminance direct-view image display capable of displaying high-resolution images efficiently with reduced power consumption and protection against sunlight, while minimizing double images and allowing flexible installation.
Implementation Method 1
a reflection type polarizing plate is arranged between the image display apparatus and the light guide, light having a specific polarization direction reflected by the reflection type polarizing plate is transmitted through the reflection surface
Implementation Method 2
the polarization direction of the light having the specific polarization direction is converted to propagate as light having a polarization direction different from the specific polarization direction to the image display apparatus by bringing the light having the specific polarization direction to pass through the waveplate twice
Implementation Method 3
a light guide configured to have a reflection surface that reflects the light output from the light source and propagates the light to an image display apparatus
Implementation Method 4
an optical means configured to reduce a divergence angle of light output from the light source
Data Source
AI summary
In an information display system that allows an observer to visually recognize image information displayed on an image display apparatus by superimposing the image on an external scenery through a window glass and a combiner, the system includes a light source apparatus that supplies light having a specific polarization direction at a narrow divergence angle to the image display apparatus, a reflection position of the image is changed by arranging a position and an angle of the image display apparatus with respect to the window glass so that the position and the angle change while a monitoring angle of the image visually recognized by the observer is constant, and a virtual image display distance of the image visually recognized by the observer and a size of the image of the virtual image can be changed by the arrangement state in the vehicle.