Head-Up Display Lens Gradient Refractive Index Ghosting
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Solution Overview
Problem
Head-up display systems often suffer from ghosting issues, where secondary images appear offset from the primary image, making the display appear blurry and unclear, especially at high incident angles and with anti-reflection coatings that fail to minimize ghost image intensity effectively.
Innovation Solution
A head-up display system incorporating a projector and a lens with a cured anti-reflection film on its surface, formed from an anti-reflection coating composition, which refracts and minimizes the intensity of ghost images by optimizing the incident angle and intensity ratios of light rays, ensuring a clear and crisp primary image is presented without visible ghosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional lens with anti-reflection coating is used in a head-up display system, then the primary image brightness is improved, but ghost images appear with significant intensity making the display blurry and unclear
Solution Approach 1:
The patent applies a gradient refractive index to specific regions of the lens, creating local variations in optical properties. The refractive index changes from the center toward the edges of the lens, which selectively manages light rays at different positions and angles, thereby reducing ghost images while preserving primary image quality.
Solution Approach 2:
The patent modifies the refractive index parameter of the lens material in a gradient distribution. By changing the refractive index from a uniform value to a gradient distribution (higher at the center, lower at the edges), the system controls the bending of light rays to eliminate ghost images while maintaining bright primary image display.
2Area of stationary object
If the incident angle of light rays is increased to improve field of view, then the display coverage is improved, but ghost image intensity increases making the display unclear
Solution Approach 1:
The gradient refractive index is applied locally across different regions of the lens, with higher refractive indices at the center and lower indices at the edges. This local variation allows the lens to handle different incident angles appropriately, maintaining ghost-free images across the entire field of view without sacrificing display coverage.
3Ease of manufacture
If a uniform refractive index lens is used, then the manufacturing is simpler, but ghost images are not effectively minimized
Solution Approach 1:
The patent transitions from a uniform refractive index to a gradient refractive index distribution. This parameter change enables effective ghost image minimization while remaining compatible with standard lens manufacturing processes, as the gradient can be achieved through controlled material composition or post-processing techniques.
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 system effectively reduces ghost image luminance to less than 1% of the primary image luminance, ensuring a clear, singular, and bright primary image is visible to the operator, even at high incident angles and for tall operators, thereby enhancing display clarity and reducing ghost image visibility.
Implementation Method 1
The lens is configured for refracting the first ray of light to emit from the second surface a second ray of light having a second intensity that is less than the first intensity, and a third ray of light that is parallel to the second ray of light
Implementation Method 2
a cured film disposed on the first surface and formed from an anti-reflection coating composition, wherein the cured film is configured for minimizing the third intensity
Data Source
AI summary
A head-up display system includes a projector configured for emitting a first ray of light having a first intensity, and a lens having a first surface facing the projector and a second surface spaced apart from the first surface. The lens is configured for refracting the first ray of light to emit from the second surface a second ray of light having a second intensity that is less than the first intensity, and a third ray of light that is parallel to the second ray of light and has a third intensity that is less than the second intensity. The system also includes a cured film disposed on the first surface and formed from an anti-reflection coating composition, wherein the cured film is configured for minimizing the third intensity. A device includes a windshield, an operator eyebox spaced apart from the windshield, and the head-up display system.