Anamorphic Condenser Lens for HUD Illumination
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Solution Overview
Problem
Conventional head-up display devices face challenges in enhancing visibility of virtual images due to limitations in light condensation efficiency, particularly with toroidal surfaces that are single convex surfaces matching the illumination target surface, leading to insufficient visibility of projected images.
Innovation Solution
The head-up display device employs a light condensing unit with a condenser lens array where each lens element is paired with a light emitting device, featuring anamorphic surfaces with different curvatures in the x-direction and y-direction, allowing for efficient light condensation and improved alignment with light emitting devices to enhance image visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single convex toroidal surface is used in the condenser lens, then the lens can be manufactured with a simple structure, but the light condensation efficiency is insufficient and visibility of the virtual image is not enhanced sufficiently
Solution Approach 1:
The condenser lens is divided into multiple lens elements (first, second, and third lens elements) with different surface configurations. Each lens element handles specific light condensation tasks, allowing the system to achieve high light condensation efficiency while maintaining manufacturing feasibility through modular design.
Solution Approach 2:
The patent employs asymmetric surface designs including concave and convex surfaces with different curvatures in different directions (toroidal and aspherical surfaces). This asymmetric configuration optimizes light condensation efficiency and enables precise control over illumination distribution, thereby enhancing virtual image visibility.
2Illumination intensity
If a large curvature is set in the toroidal surface, then light condensation efficiency may be improved, but the surface size constraint makes it difficult to achieve sufficient condensation across the entire illumination target surface
Solution Approach 1:
The condenser lens is segmented into multiple lens elements, each with optimized curvature. This allows different regions of the illumination target surface to receive adequately condensed light without requiring any single surface to have excessively large curvature, thereby maintaining both condensation efficiency and broad surface coverage.
Solution Approach 2:
Each lens element is designed with specific local surface properties (concave or convex toroidal or aspherical surfaces) tailored to its position and function. This local optimization ensures that light condensation efficiency is maximized in each region while collectively covering the entire illumination target surface.
3Device complexity
If the toroidal surface collectively condenses illumination light from all light emitting devices, then the structure is simple, but the light cannot be efficiently condensed according to the specific layout of respective light emitting devices
Solution Approach 1:
The condenser lens is divided into multiple lens elements, each associated with specific light emitting devices. This segmentation allows each lens element to be optimized for its specific light sources, improving light condensation precision according to the layout of individual light emitting devices while maintaining manageable structural complexity through modular design.
Solution Approach 2:
Each lens element is designed with specific surface characteristics (concave or convex toroidal or aspherical surfaces) that are locally optimized for its position relative to the light emitting devices. This local quality optimization enables precise light condensation tailored to each device's layout requirements.
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
This configuration enables efficient illumination of the image forming unit, resulting in improved visibility of the virtual image projected onto a windshield or combiner, optimizing the illumination range and reducing luminance unevenness.
Implementation Method 1
The light condensing unit is configured to collect the illumination light from each of the light emitting devices and to cause the illumination light to be incident on the illumination target surface
Implementation Method 2
Each of the light condensing surfaces is an anamorphic surface formed in a convex shape in which a curvature in an x-direction and a curvature in a y-direction are different from each other
Data Source
AI summary
An illumination light from each light emitting device illuminates a corresponding region of an image forming unit to form an image. A light condensing unit has multiple lens elements paired with the respective light emitting devices. Each condenser lens element has a light condensing surface to condense the illumination light. A z-direction is a direction connecting a surface vertex of the light condensing surface with the light emitting device paired with the surface vertex. An x-direction and a y-direction are orthogonal to each other on a virtual plane orthogonal to the z-direction. The pair of the condenser lens element and the light emitting device is aligned in at least one of the x-direction and the y-direction. Each light condensing surface is formed in a convex shape in which a curvature in the x-direction and a curvature in the y-direction are different from each other.