Vehicular Display Optical Path Glare Reduction
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Solution Overview
Problem
Conventional vehicular display apparatuses suffer from reflected glare due to outside light entering from the side window, which affects the visibility of the rear image displayed to the driver.
Innovation Solution
The display apparatus incorporates a concave mirror with a specific optical path configuration, including a first λ/4 plate, a half mirror with a second λ/4 plate and a reflective polarizing plate, and a concave mirror with a reflection angle different from the incident light, to redirect outside light away from the driver's position, preventing glare and allowing for adjustable field of view and reduced image distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional display apparatus is used with a concave mirror, then the rear image can be displayed to the driver, but reflected glare from outside light enters from the side window and reduces visibility
Solution Approach 1:
The patent changes the spatial arrangement by setting the longitudinal direction of the display surface and the longitudinal direction of the concave mirror to intersect at a predetermined angle (e.g., 30 degrees). This angular offset in the top view creates a geometric relationship that prevents outside light from the side window from being reflected into the driver's position, while still allowing the optical path to function properly for displaying the rear image.
Solution Approach 2:
The patent introduces asymmetry in the optical path configuration by using a specific angle of intersection between the display surface longitudinal direction and the concave mirror longitudinal direction. This asymmetric angular relationship (e.g., 30 degrees) breaks the symmetry that would otherwise allow glare to enter, creating an optimized configuration where the display surface is elongate in the longitudinal direction and the mirrors are positioned at non-perpendicular angles.
2Device complexity
If the optical path is simplified, then the device complexity is reduced, but image distortion increases and field of view adjustability is limited
Solution Approach 1:
The patent introduces adjustability by allowing the angle between the longitudinal direction of the display surface and the longitudinal direction of the concave mirror to be changed. This dynamic configuration enables the field of view to be adjusted while maintaining proper optical path lengths, thereby reducing image distortion without requiring an overly complex fixed optical system.
Solution Approach 2:
The patent optimizes image quality by carefully controlling the optical path lengths through the various optical components (first λ/4 plate, half mirror with second λ/4 plate and reflective polarizing plate, concave mirror). By adjusting and equalizing these optical path lengths as parameters, the system achieves reduced image distortion and enhanced image quality without requiring excessive structural 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
This configuration effectively prevents reflected glare, enhances image quality by equalizing optical path lengths, and allows for adjustable field of view, improving the driver's visibility of the rear image without distortion.
Implementation Method 1
a first λ/4 plate that is located on a display surface of the display device and changes a phase of the emission light incident on the first λ/4 plate
Implementation Method 2
the half mirror includes a second λ/4 plate that changes a phase of the emission light incident on the second λ/4 plate
Implementation Method 3
a reflective polarizing plate that reflects a first polarized light component and transmits a second polarized light component different from the first polarized light component
Implementation Method 4
a concave mirror that reflects emission light toward outside of the display apparatus
Data Source
AI summary
A display apparatus includes a first mirror and a half mirror between a display device and a concave mirror. The first mirror reflects emission light emitted from an elongate display surface of the display device, toward the half mirror. The half mirror reflects the light reflected by the first mirror, toward the concave mirror. The concave mirror reflects the light reflected by the half mirror, toward the half mirror. In a top view of the display apparatus, a line passing through a center of the display surface in a longitudinal direction and parallel to the longitudinal direction and a tangent line passing through a center of a reflection surface of the concave mirror in a longitudinal direction and parallel to the longitudinal direction intersect at a predetermined angle.