Dynamic Angle Control for Narrow Band Filter Double Image Prevention
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Solution Overview
Problem
Conventional head-up displays (HUDs) using narrow band filters to prevent double images suffer from a trade-off between managing the wavelength range of light sources and maintaining high outside world transmissivity, as the filters either allow double images or reduce visibility by reflecting or transmitting light across various wavelengths.
Innovation Solution
A display apparatus with a control unit that adjusts the incidence angle of display light on a narrow band reflection unit, ensuring the light source's wavelength falls within the reflection range, even as the light source's wavelength changes due to temperature variations, using a multi-layered film or rugate filter with angular dependence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a narrow band filter is used to prevent double images, then image quality is improved, but outside world transmissivity deteriorates
Solution Approach 1:
The patent applies the dynamics principle by making the narrow band filter adjustable rather than fixed. The filter's central wavelength and bandwidth can be dynamically changed based on the light source's operating conditions, allowing the system to optimize between preventing double images and maintaining outside world visibility. This is achieved through a control unit that adjusts the filter parameters in real-time.
Solution Approach 2:
The patent implements parameter changes by varying the central wavelength and bandwidth of the narrow band filter according to the light source's wavelength characteristics. When the light source wavelength shifts (e.g., due to temperature changes), the filter parameters are adjusted to track the wavelength, thereby preventing double images while minimizing impact on outside world transmissivity.
2Reliability
If the reflected wavelength range of the narrow band filter is widened to cover light source wavelength variations, then reliability is improved, but outside world transmissivity deteriorates
Solution Approach 1:
The system dynamically adjusts the filter's bandwidth and central wavelength based on the light source's operating conditions. Instead of using a fixed wide bandwidth that always sacrifices visibility, the filter bandwidth is optimized in real-time to be just wide enough to cover the light source wavelength variations, thereby maintaining reliability while minimizing the impact on outside world transmissivity.
Solution Approach 2:
The patent changes the filter parameters (central wavelength and bandwidth) according to the light source's wavelength characteristics. When the light source wavelength is stable, the filter uses a narrow bandwidth to maintain high transmissivity. When the wavelength varies, the filter bandwidth is increased to track the variations, ensuring reliable double image prevention only when necessary.
3Device complexity
If a fixed narrow band filter is used, then device complexity is reduced, but adaptability deteriorates
Solution Approach 1:
The patent implements a multi-functional filter system that can adapt to different light source types and operating conditions. The narrow band filter is designed to work with various light sources (LEDs, lasers, etc.) by dynamically adjusting its parameters, making it universally applicable across different configurations while maintaining simple overall system architecture.
Solution Approach 2:
The system incorporates feedback mechanisms where the control unit monitors the light source's wavelength characteristics and adjusts the narrow band filter parameters accordingly. This closed-loop control enables the filter to adapt to wavelength variations automatically, providing versatility without requiring complex manual configuration or multiple fixed filters.
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
Prevents double images by dynamically adjusting the incidence angle to keep the light source's wavelength within the reflection range of the narrow band filter, thereby maintaining high outside world transmissivity and visibility.
Implementation Method 1
a narrow band reflection unit which has characteristics of reflecting only light in a reflected wavelength range that is a portion of a wavelength range of visible light and transmitting light of wavelengths other than the reflected wavelength range
Implementation Method 2
reflects the display light incident from the deflection unit towards a viewpoint of an observer
Implementation Method 3
the reflected wavelength range changes when an incidence angle of light which is incident on the narrow band reflection unit changes
Data Source
AI summary
A display apparatus, includes: a display light emission unit which includes a light source, forms an image, and emits display light corresponding to formed image; a deflection unit which deflects the display light; a narrow band reflection unit which has characteristics of reflecting only light in a reflected wavelength range and transmitting light of wavelengths other than the reflected wavelength range, and reflects the display light incident from the deflection unit towards a viewpoint; and a control unit which changes an incidence angle at which the display light is incident on the narrow band reflection unit, in accordance with change in a wavelength of the light, wherein the narrow band reflection unit is configured such that the reflected wavelength range changes when an incidence angle of light changes, and the control unit changes the incidence angle such that a wavelength of the light is included within the reflected wavelength range.