Head-Up Display Spectrally Selective Filter Image Blurring
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Solution Overview
Problem
Conventional head-up displays suffer from image blurring due to imperfections in the mirror and image generation units, which reduces the readability of projected information for the driver.
Innovation Solution
A spectrally selective optical filter, such as a dichroic mirror, is used to reflect light in specific wavelengths and transmit light in others, ensuring that images from two image generation units are filtered to prevent overlapping defects, with a reflection coefficient of at least 90% for certain wavelengths and transmission coefficients of at least 90% for others, allowing clear projection of images in the driver's field of vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional mirror is used to project images from two image generation units, then the device complexity is reduced, but the images blur with respect to each other reducing readability
Solution Approach 1:
The patent applies parameter changes by introducing a spectrally selective optical filter that differentiates between two wavelength bands. The filter is configured to reflect a first wavelength band from one image generation unit while transmitting a second wavelength band from another image generation unit, thereby preventing image blurring through spectral parameter differentiation rather than spatial separation alone.
Solution Approach 2:
The patent employs composite materials by using a spectrally selective optical filter with specific reflective and transmissive properties for different wavelengths. This composite optical component combines multiple functional characteristics (wavelength-selective reflection and transmission) into a single element, enabling clear separation of images from multiple generation units without requiring complex mechanical arrangements.
2Adaptability or versatility
If multiple image generation units are placed at different distances from the mirror, then different image distances are achieved, but image blurring occurs due to imperfections in the mirror and image generation units
Solution Approach 1:
The patent resolves the contradiction between image distance variation and image sharpness by changing the spectral parameter rather than relying solely on spatial positioning. The spectrally selective filter maintains image sharpness by separating wavelengths, allowing multiple image generation units at different distances to project clear images without mutual blurring.
Solution Approach 2:
The spectrally selective optical filter acts as an intermediary element between the multiple image generation units and the driver's field of view. It mediates the interaction between different wavelength bands, selectively reflecting one band while transmitting another, thereby preventing direct interference between images from units at different distances.
3Manufacturing precision
If a spectrally selective optical filter is introduced to prevent image blurring, then image readability is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the wavelength separation function from the mechanical positioning system and embeds it within the optical filter component. By taking out the spectral discrimination capability and integrating it into the filter, the system achieves image separation without requiring complex mechanical adjustments or multiple precisely positioned components.
Solution Approach 2:
The spectrally selective optical filter performs multiple functions simultaneously: it separates images by wavelength, prevents image blurring, and enables multiple image generation units to operate at different distances. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in overall 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
The solution effectively filters images to prevent blurring, enhancing the readability and clarity of information projected to the driver, improving the overall usability and safety of the head-up display system.
Implementation Method 1
the mirror is a spectrally selective optical filter adapted to mainly reflect the light in at least a first wavelength, and to mainly transmit the light in at least a second wavelength distinct from said first wavelength
Implementation Method 2
The first image generation unit comprises at least one monochromatic light source, which emits only in said first or respectively in said second wavelength
Implementation Method 3
said first image generating unit is a laser scanner which comprises at least one laser diode emitting a wavelength included in the wavelength band
Data Source
Figure 1~2
AI summary
The invention relates to a head-up display (10) for a motor vehicle, comprising: - a first image generation unit (11) controlled by a computer (30) to generate first images (Img1), - a second image generation unit (12), separate from the first image generation unit and controlled by a computer to generate second images (Img2), and - an optical image projection assembly (18), which is adapted to project the first and second images into the field of vision of the driver of the motor vehicle, and which comprises a partially reflective mirror, on either side of which the first and second image generation units are placed.According to the invention, the mirror includes a spectrally selective optical filter (19), adapted to predominantly reflect, or respectively transmit, light in at least one particular wavelength, and to predominantly transmit, or respectively reflect, light in at least one band of wavelengths which does not include said particular wavelength.