Self-Centering HUD Mirror Holder Reduces Tolerance Stack-Up
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Solution Overview
Problem
Conventional head-up display (HUD) systems face challenges in achieving high precision and manufacturability due to the use of extended arms or levers for switch actuation, which increase tolerance stack-up and complicate the mirror holder design, leading to reduced image accuracy and increased risk of breakage.
Innovation Solution
A self-centering mirror holder with a rotational axis-aligned activation feature and minimal proximity to the calibration switch, utilizing a cylindrical shape with integrated activation features and a conical self-centering shaft, eliminates the need for secondary parts and reduces tolerance stack-up, enhancing precision and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an extended arm or lever is used to connect the mirror holder and limit switch for switch actuation, then the activation face is offset from the rotational axis of the mirror, but this increases the proximity of the activation face to the limit switch and complicates the manufacturability of the mirror holder, resulting in increased tolerance stack-up and diminished image accuracy
Solution Approach 1:
The patent removes the extended arm or lever from the mirror holder design. Instead, the activation feature is directly formed on the mirror holder body, eliminating the intermediate connecting component. This extraction of the problematic element reduces tolerance stack-up and simplifies the mirror holder structure while maintaining the ability to actuate the limit switch.
Solution Approach 2:
The activation feature is integrated directly into the mirror holder body, merging the functions of mirror retention and switch actuation into a single component. This consolidation eliminates the need for separate arms or levers, reducing the number of parts and tolerance accumulation points, thereby improving image accuracy and simplifying manufacturing.
2Ease of operation
If an extended arm or lever is used for switch actuation, then the activation face can be positioned away from the rotational axis, but this increases tolerance stack-up and reduces image accuracy
Solution Approach 1:
The extended arm or lever that caused tolerance accumulation is removed from the design. The activation feature is instead directly formed on the mirror holder, eliminating the intermediate component that introduced manufacturing precision errors while preserving switch actuation functionality.
Solution Approach 2:
Instead of extending the activation face away from the rotational axis through an arm or lever, the patent inverts the approach by positioning the activation feature directly on the mirror holder at the rotational axis location. This inversion eliminates the tolerance propagation path while maintaining operational capability.
3Ease of manufacture
If conventional mirror holder designs with arms or levers are used, then switch actuation is possible, but the manufacturability is complicated and scrap rate increases due to breakage risk
Solution Approach 1:
The activation feature is merged into the mirror holder body as an integrated component rather than a separate arm or lever. This consolidation simplifies manufacturing processes and eliminates weak connection points that were prone to breakage, thereby improving both manufacturability and reliability.
Solution Approach 2:
The fragile extended arms or levers are extracted from the design and replaced with a robust integrated activation feature on the mirror holder. This removal of vulnerable components eliminates the breakage risk while maintaining switch actuation capability, improving overall system reliability.
Data Source
AI summary
A head up display mirror holder arrangement for a motor vehicle includes a picture generation unit producing a light field. A mirror reflects the light field such that the light field is visible to the driver as a virtual image. A mirror holder has two opposite ends and an activation feature. The two opposite ends are aligned along a rotational axis of the mirror. The mirror holder retains the mirror. Each of two bushings is coupled to a respective opposite end of the mirror holder. A calibration switch has minimum proximity to the activation feature of the mirror holder.