Stepped Diffuser HUD Optics for Multi-Plane Virtual Images
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Solution Overview
Problem
Existing head-up displays (HUDs) struggle to efficiently project multiple images at different distances from the viewer, requiring two sets of optics which increase complexity and size.
Innovation Solution
A head-up display system with a spatial light modulator and a stepped screen assembly, utilizing a diffractive pattern to project first and second picture content on different diffusers at distinct virtual image planes, achieved through a single optical system with varying optical powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two sets of optics are used to project multiple images at different distances, then the projection capability is improved, but the device complexity and size increase
Solution Approach 1:
A single optical system is designed to perform multiple functions by projecting different picture content to different virtual image planes. The optical system uses a spatial light modulator to display diffractive patterns that encode multiple images, and through optical elements with varying optical powers, it forms virtual images at different distances, eliminating the need for separate optical systems for each image plane.
Solution Approach 2:
The patent introduces a stepped screen assembly where diffusers are arranged at different perpendicular distances from the spatial light modulator. This spatial arrangement in the depth dimension allows different picture content to be projected onto different diffusers, creating virtual images at different distances from the viewer using a single optical system.
2Adaptability or versatility
If two sets of optics are used to project multiple images at different distances, then the projection capability is improved, but the device size increases
Solution Approach 1:
The patent merges the functionality of multiple optical systems into a single integrated optical system. By combining the spatial light modulator, stepped screen assembly with multiple diffusers, and optical elements with varying optical powers into one system, it achieves multi-plane image projection without requiring separate optical systems, thereby reducing the overall device volume.
Solution Approach 2:
The stepped screen assembly utilizes the depth dimension by positioning diffusers at different perpendicular distances from the spatial light modulator. This vertical stacking arrangement allows multiple images to be projected in the depth direction, enabling multi-plane display functionality within a compact form factor without requiring lateral expansion of the device.
3Device complexity
If a single optical system is used to project multiple images at different distances, then the device complexity is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The optical system is segmented into distinct functional components: a spatial light modulator for displaying diffractive patterns, a stepped screen assembly with multiple diffusers at different positions, and optical elements with specific optical powers. This segmentation allows each component to be optimized and manufactured separately with precise specifications, facilitating controlled assembly and alignment while reducing overall system complexity.
Solution Approach 2:
The patent employs optical elements with varying optical powers to form virtual images at different distances. By carefully selecting and adjusting the optical power parameters of these elements, the system achieves precise control over virtual image plane positions. This parameter-based control allows for flexible design and manufacturing tolerance management.
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
Enables the projection of multiple images at different distances using a single optical system, reducing complexity and size while maintaining image quality.
Implementation Method 1
A spatial light modulator arranged to modulate the amplitude and/or phase of incident light. Light modulation may be achieved using electrically-addressable liquid crystals, optically-addressable liquid crystals or micro-mirrors, for example.
Implementation Method 2
The hologram may be reconstructed by illumination with suitable light to form a two-dimensional or three-dimensional holographic reconstruction, or replay image, representative of the original object.
Implementation Method 3
an optical system having at least one optical element having optical power. The optical system and the screen assembly are arranged so that the first and second diffusers have different object distances to the optical system
Data Source
AI summary
A head-up display is described. A spatial light modulator is arranged to display a diffractive pattern of first picture content and/or second picture content. A screen assembly has first and second diffusers arranged in a stepped configuration so that the first diffuser is spatially offset from the second diffuser by a perpendicular distance. A light source is arranged to illuminate the diffractive pattern such that the first picture content is formed on the first diffuser and/or the second picture content is formed on the second diffuser. An optical system comprising at least one optical element having optical power is arranged so that the first and second diffusers have different object distances to the optical system.