Vehicle Display Optical Path Light Loss Reduction
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Solution Overview
Problem
Existing display devices for stereoscopic image display face challenges in maintaining light efficiency and achieving a deep depth feel, particularly in vehicle cabin environments where light loss occurs when image light passes through half mirrors.
Innovation Solution
The proposed display device incorporates a configuration with a first display unit emitting phase-shifted image light, a polarizing half mirror, a reflective mirror, and a λ/4 plate to inhibit light loss and create a deep depth feel by adjusting the optical path lengths of image light beams, and a second configuration using a half mirror and reflective mirrors to direct image light in a way that enhances depth perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If image light passes through a half mirror in existing display devices, then the display device can achieve stereoscopic image display, but light loss occurs reducing display efficiency
Solution Approach 1:
The patent divides the display surface into multiple regions (first region, second region, third region, fourth region) with different optical paths. Each region uses a combination of polarizing half mirrors and reflective mirrors to direct image light, reducing overall light loss while maintaining stereoscopic display functionality.
Solution Approach 2:
The patent introduces λ/4 plates as intermediary optical elements between the display unit and polarizing half mirrors. These λ/4 plates convert linearly polarized light to circularly polarized light and back, enabling more efficient light transmission through the optical system and reducing light loss.
2Reliability
If multiple reflective mirrors are used to create depth feel, then stereoscopic display performance improves, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated optical components. The polarizing half mirrors serve dual purposes: separating image light into different optical paths and controlling polarization states. The λ/4 plates are strategically positioned to simultaneously affect multiple light beams, reducing the number of separate components needed.
Solution Approach 2:
The patent uses the polarization dimension (vertical/horizontal, left/right circular polarization) to create separate optical paths without requiring physically separated channels. This allows multiple image light beams to be multiplexed through the same spatial path using different polarization states, reducing optical path 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
The solution effectively inhibits light loss and achieves a significant depth feel by optimizing the optical paths of image light, allowing for a wider variety of image expressions and improved display performance in vehicle cabin settings.
Implementation Method 1
a first polarizing half mirror that transmits one of the first image light or the second image light and reflects an other of the first image light or the second image light
Implementation Method 2
a first λ/4 plate disposed between the first reflective mirror and the first polarizing half mirror on the one of the transmissive optical path or the reflective optical path
Implementation Method 3
a first reflective mirror disposed on one of a transmissive optical path along which the one of the first image light or the second image light passes through the first polarizing half mirror or a reflective optical path along which the other of the first image light or the second image light reflects off the first polarizing half mirror
Implementation Method 4
a half mirror including one end portion disposed at a boundary between the third region and the fourth region; and a third reflective mirror that reflects, toward the half mirror, the third image light emitted from the third region and reflected by the half mirror, the half mirror is oriented to direct the third image light and the fourth image light in a same direction
Data Source
AI summary
A first configuration of a display device includes: a first display unit that emits first image light and second image light; a first polarizing half mirror that transmits one of the first or second image light and reflects the other; a first reflective mirror on an optical path of the first polarizing half mirror; and a first λ/4 plate between the first reflective mirror and the first polarizing half mirror. A second configuration includes: a second display unit that emits third image light and fourth image light; a half mirror; and a third reflective mirror that reflects, toward the half mirror, the third image light reflected by the half mirror. A third configuration includes: a second display element; and a first reflector that reflects fifth image light from the second display element. The first reflector includes reflective surfaces for forming display images based on the fifth image light.