Catadioptric HUD Collimator with Diffractive Field Lens
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Solution Overview
Problem
Conventional Head-Up Displays (HUDs) are large, expensive, and difficult to fit into smaller aircraft due to their large optical components, which are also costly and challenging to align in compact spaces, necessitating a need for a compact, low-cost, lightweight, and high-resolution projector system optimized for constrained spaces.
Innovation Solution
A compact HUD system utilizing a catadioptric optical system with a collimating mirror, polarizing beam splitter, field lens with diffractive surface, and a curved reflector, which eliminates the need for a corrector lens and reduces the number of optical components, allowing for a smaller and more affordable projector with improved color correction and aberration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional HUD optical components (lens, prisms, mirrors) are used to form adequate field of view and viewing eye box, then the HUD provides sufficient optical performance, but the volume and weight of the system become too large to fit within constrained cockpit spaces
Solution Approach 1:
The patent combines multiple optical functions (collimation, field of view formation, eye box preservation) into a single integrated waveguide component. The waveguide integrates the combiner, collimator, and field lens functions that were previously separate components, thereby reducing the overall HUD system volume while maintaining adequate optical performance
Solution Approach 2:
The patent embeds the optical functionality within the waveguide structure itself. The collimating and field-of-view-forming functions are nested within the waveguide substrate, allowing the HUD system to occupy significantly reduced volume compared to conventional designs with separate optical components
2Reliability
If conventional HUD optical components are used to achieve adequate field of view and viewing eye box, then the HUD provides sufficient optical performance, but the cost and complexity of alignment become prohibitive for smaller aircraft
Solution Approach 1:
The patent merges multiple alignment-critical components (combiner, collimator, field lens) into a single waveguide unit. This integration eliminates the complex multi-component alignment procedures required in conventional HUDs, reducing device complexity and making the system more suitable for smaller aircraft with limited budgets
Solution Approach 2:
The waveguide structure provides self-alignment of optical functions through its integrated design. The collimating and field-of-view-forming functions are inherently aligned within the waveguide substrate, eliminating the need for manual alignment procedures and reducing device complexity
3Reliability
If conventional HUD optical components are used to form adequate field of view and viewing eye box, then the HUD provides sufficient optical performance, but the weight becomes too high for smaller aircraft and wearable displays
Solution Approach 1:
The patent combines multiple heavy optical components (lens, prisms, mirrors) into a single lightweight waveguide structure. This integration dramatically reduces the overall weight of the HUD system while maintaining adequate optical performance for field of view and eye box formation
Solution Approach 2:
The patent embeds optical functions within the waveguide substrate, eliminating the need for separate heavy optical components. The nested integration of collimating and field-of-view-forming functions within the waveguide structure results in significant weight reduction suitable for smaller aircraft and wearable displays
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 results in a significantly smaller HUD system volume, reduced weight, and lower costs while maintaining high resolution and efficiency, making it suitable for smaller aircraft and wearable displays with enhanced field of view and eye box preservation.
Implementation Method 1
Light from the image source enters the beam splitter and is reflected toward the collimating mirror. The light striking the collimating mirror is reflected through the polarizing beam splitter
Implementation Method 2
polarizing beam splitter having a first face, a second face, and a third face. Light from the image source enters the beam splitter and is reflected toward the collimating mirror
Implementation Method 3
The field lens has a diffractive surface for increasing power of the field lens and providing color correction
Implementation Method 4
a curved reflector disposed to receive light from the retarder and provide the light from the retarder to the second face
Data Source
AI summary
A head up display can use a catadioptric collimating system. The head up display includes an image source. The head up display also includes a collimating mirror, and a polarizing beam splitter. The light from the image source enters the beam splitter and is reflected toward the collimating mirror. The light striking the collimating mirror is reflected through the beam splitter toward a combiner. A field lens can include a diffractive surface. A corrector lens can be disposed after the beam splitter.