Wedge Interlayer Film for HUD Laminated Glass Double-Image Suppression
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Solution Overview
Problem
Conventional interlayer films for laminated glass fail to sufficiently suppress double images, despite controlling the wedge angle, which hinders the visibility of information displayed in head-up displays.
Innovation Solution
An interlayer film with a wedge angle of 0.2 mrad or more, featuring one end thicker than the other, and a controlled thickness variation within specific segments, ensuring an absolute difference in thickness change of 32 µm or less, is used to suppress double images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a wedge-shaped interlayer film is used to suppress double images, then the visibility of displayed information is improved, but the manufacturing precision requirement increases due to strict control of thickness variation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the wedge angle (0.2 mrad or more) and thickness variation (absolute difference of 32 µm or less) of the interlayer film. By optimizing these physical parameters, the film focuses reflected light into a single point, suppressing double images while maintaining manufacturability through defined tolerance ranges.
Solution Approach 2:
The patent employs asymmetry by using a wedge-shaped interlayer film with non-uniform thickness. The film has one end thicker than the other, creating an asymmetric structure that redirects reflected light paths. This asymmetric geometry is essential for focusing reflections from both glass plates into a single point, thereby eliminating double images in head-up displays.
2Reliability
If the wedge angle is increased to suppress double images, then the image focusing effect is improved, but the thickness variation becomes more difficult to control
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range: wedge angle of 0.2 mrad or more for reliable double image suppression, combined with a maximum thickness variation of 32 µm. This parameter optimization ensures that the focusing effect is achieved while keeping thickness variation within controllable manufacturing tolerances.
3Illumination intensity
If the thickness variation is strictly controlled to suppress double images, then the display quality is improved, but the ease of manufacture decreases
Solution Approach 1:
The patent balances display quality and ease of manufacture by defining a practical thickness variation tolerance of 32 µm or less. This tolerance level is strict enough to ensure proper light focusing and double image suppression, yet loose enough to be achievable through conventional manufacturing processes with standard quality control.
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 interlayer film effectively reduces double images in laminated glass, enhancing the visibility of displayed information by focusing reflections into a single point, thereby improving the visibility in head-up displays.
Implementation Method 1
a wedge-shaped interlayer film having a prescribed wedge angle is sandwiched between a pair of glass plates... by the adjustment of the wedge angle of the interlayer film, a display of measured information reflected by one glass plate and a display of measured information reflected by the other glass plate can be focused into one point
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
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AI summary
There is provided an interlayer film for laminated glass with which double images in laminated glass can be considerably suppressed. The interlayer film for laminated glass according to the present invention has one end and the other end being at the opposite side of the one end, makes the thickness of the other end larger than the thickness of the one end, has a display corresponding region corresponding to a display area of the head-up display, and when a position apart from an end part at the one end side of the display corresponding region by 4 cm toward the other end is set to a start point, a position apart from an end part at the other end side of the display corresponding region by 4 cm toward the one end is set to an end point, spots are selected at 2-mm intervals from the start point to the end point, and the interlayer film is measured for the amount of change in the thickness within respective segments, centered on the respective spots, of 80 mm in a direction connecting the one end and the other end, makes the absolute value of a difference between the largest value among values of the amount of change in the thickness and the smallest value among values of the amount of change in the thickness 32 µm or less.