Vehicle Display Optics With Adjustable Virtual Image Distance
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Solution Overview
Problem
Existing vehicle display devices face challenges in optimizing virtual image distance based on vehicle speed and presence of objects ahead, leading to discomfort and degradation in display quality.
Innovation Solution
A vehicle display device with a controller-driven mechanism that adjusts the optical path length of output light reflected by a turning-back mirror, using a holding member that reciprocates along the optical axis, allowing for changes in virtual image distance without altering the relative positions of the display unit and turning-back mirror, thus maintaining display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the virtual image distance is increased to match the occupant's line of sight at high vehicle speeds, then the display becomes more comfortable to view, but the display quality degrades due to optical path changes
Solution Approach 1:
The patent implements dynamic adjustment of the virtual image distance by reciprocating the holding member along the optical axis based on vehicle speed. The drive mechanism enables the system to adapt the optical path length in real-time, maintaining viewing comfort across different driving conditions while preserving display quality through coordinated movement of display units and mirrors.
Solution Approach 2:
The system changes the optical path length parameter by adjusting the position of the holding member along the optical axis. This parameter change allows the virtual image distance to be optimized for different vehicle speeds, improving viewing comfort without compromising display quality through proper optical configuration.
2Ease of operation
If the virtual image position is moved forward to avoid overlap with objects ahead, then occupant comfort improves, but the optical system complexity increases
Solution Approach 1:
The patent uses dynamic reciprocation of the holding member to adjust the virtual image position forward or backward based on detection of objects ahead. This dynamic adjustment allows the system to maintain comfortable viewing by preventing virtual image overlap with real objects, while the integrated holding member design keeps the optical system relatively simple.
3Measurement precision
If multiple separate adjustment mechanisms are used to change virtual image distance, then adjustment precision improves, but device complexity and cost increase
Solution Approach 1:
The patent combines the display unit and turning-back mirror into a single holding member that reciprocates together along the optical axis. This merging of components allows for precise virtual image distance adjustment through coordinated movement, while simplifying the overall device structure and reducing the number of separate adjustment mechanisms needed.
Solution Approach 2:
The holding member serves multiple functions: it holds both the display unit and turning-back mirror, provides the reciprocating motion for optical path adjustment, and maintains the relative positional relationship between components. This multi-functionality achieves precise adjustment while reducing device complexity.
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 optimal virtual image distance adjustment based on vehicle speed and presence of objects, reducing occupant discomfort and maintaining display quality, with a simpler slide structure that avoids positional accuracy reduction and cost increases.
Implementation Method 1
a turning-back mirror that reflects, as the output light, the display light emitted from the display unit
Data Source
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AI summary
A vehicle display device (1) includes an output unit (10) that outputs output light of display information to be visually recognized as a virtual image by an occupant in a vehicle cabin, a reflector (30) that directly or indirectly receives the output light, and reflects the output light toward an eye box (EB) indicating a region in which the occupant can visibly recognize the virtual image, and a controller (20) that controls an operation of the output unit. The output unit (10) includes a display unit (11) that emits the display information as display light, a turning-back mirror (12) that reflects, as the output light, the display light emitted from the display unit (11), a holding member (13) that holds the display unit (11) and the turning-back mirror (12) without changing relative positions of the display unit (11) and the turning-back mirror (12), and a drive mechanism (14) that can reciprocate the holding member (13) along an optical axial direction of the turning-back mirror (12).