Vehicular Head-Up Display Illumination Optical System
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Solution Overview
Problem
Current vehicle head-up display systems have inefficiencies in the use of illumination light due to polarization filters only allowing specific polarized components to pass through the display panel, leading to suboptimal light utilization.
Innovation Solution
A display device configuration that includes a light source device, a transmission-type display panel, an illumination optical system with a quarter-wave plate, a reflective polarizer, lenses, a diffusing plate, and second reflectors, which guides and converts non-polarized illumination light to enhance transmission efficiency by reflecting and reorienting polarized components for optimal display light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a polarization filter is used to select a particular polarized component of illumination light, then the display quality is improved, but the use efficiency of illumination light deteriorates because other polarized components are blocked
Solution Approach 1:
A quarter-wave plate is introduced as an intermediary optical element between the light source and the polarization filter. This wave plate converts linearly polarized light into circularly polarized light, allowing both s-wave and p-wave components to pass through the system after multiple reflections, thereby improving illumination light utilization while maintaining display quality
Solution Approach 2:
The system enables continuous utilization of illumination light by arranging mirrors and optical elements to reflect both polarized components multiple times through the display panel. The s-wave is reflected by the functional film and the p-wave is reflected by the second mirror, with both paths contributing to useful display light output, eliminating the waste of blocking entire polarized components
2Reliability
If only a particular polarized component is transmitted through the display panel, then the polarization selectivity is improved, but the illumination light utilization deteriorates
Solution Approach 1:
The optical system dynamically handles different polarized components through multiple reflection paths. The quarter-wave plate and mirror arrangement create dynamic optical paths where s-wave and p-wave components are sequentially reflected and converted, allowing both to contribute to the final display output while maintaining polarization selectivity at each stage
Solution Approach 2:
The system changes the polarization state parameter of light through the quarter-wave plate, converting linear polarization to circular polarization. This parameter change enables both s-wave and p-wave components to be utilized effectively, transforming the static polarization filtering approach into a dynamic multi-path utilization system
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 significantly increases the use efficiency of illumination light by ensuring that both polarized components are effectively utilized, resulting in improved display light quality and reduced wavelength intensity variations, thereby enhancing the virtual image visibility for the operator.
Implementation Method 1
an s-wave to be reflected by the functional film and emitted towards the display panel and causes another polarized component (p-wave) to be transmitted by the functional film to reach the second mirror. The p-wave reflected at the second mirror is converted to circularly polarized light upon passing through the retardation plate
Implementation Method 2
causes a certain polarized component (s-wave) within the non-polarized illumination light emitted by the light source device to be reflected by the functional film
Implementation Method 3
a first mirror and a second mirror that face each other
Data Source
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AI summary
A display device and a vehicle head-up display apparatus of the present disclosure include a substrate (15), light source devices (11), a transmission-type display panel (12), and an illumination optical system (13). The light source devices (11) are disposed on the substrate (15). The illumination optical system (13) guides illumination light from the light source devices (11) to the display panel (12). The illumination optical system (13) includes a first reflector (131), a quarter-wave plate (132), and a reflective polarizer (133). The first reflector (131) is disposed at a different position on the substrate (15) than the light source devices (11). The quarter-wave plate (132) is disposed between the first reflector (131) and the display panel (12). The reflective polarizer (133) is disposed between the quarter-wave plate (132) and the display panel (12).