Polarization-Split Projection Optics for Compact Dual Displays
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Solution Overview
Problem
Existing display devices face challenges in downsizing while improving the utilization efficiency of light from the light source.
Innovation Solution
The display device incorporates a first and second projection optical system with an illumination optical system that splits light from a single light source into two polarized states, using a polarization beam splitter and a retardation plate to align polarization states and guide light to separate displays, allowing for efficient use of light without discarding any portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single light source is used to illuminate both projection optical systems, then device size is reduced, but light utilization efficiency is insufficient
Solution Approach 1:
The patent segments the light from a single light source into two separate polarization states using a polarization beam splitter. This allows the light to be divided into first light and second light that can independently illuminate different projection optical systems, thereby improving light utilization efficiency while maintaining the benefit of using only one light source
Solution Approach 2:
The patent changes the polarization state parameter of light by introducing a retardation plate that converts the polarization direction of at least one of the split light beams. This parameter change enables the light to be properly directed to the appropriate projection optical system, resolving the contradiction between using a single light source and achieving efficient light utilization
2Loss of energy
If polarization conversion units are added to improve light utilization, then light efficiency improves, but device complexity and size increase
Solution Approach 1:
The polarization beam splitter serves multiple functions: it divides the light from a single source into two separate beams and simultaneously prepares them for different polarization requirements. This multi-functionality reduces the need for additional separate polarization conversion units, thereby improving light utilization without proportionally increasing device 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 achieves downsizing of the display device while enhancing light utilization efficiency, reducing manufacturing costs, and ensuring uniform luminance distribution across both displays.
Implementation Method 1
a polarization beam splitter including a split surface where the light source light is split into first light in a first polarization state and second light in a second polarization state
Implementation Method 2
a light source that collimates light source light including first polarized light and second polarized light and emits the collimated light
Data Source
AI summary
A display device includes: a first projection optical system including a first display; a second projection optical system including a second display; and an illumination optical system that guides light to the first and second projection optical systems. The illumination optical system includes a light source that collimates light source light including first and second polarized light and emits the collimated light, and a polarization beam splitter including a split surface where the light source light is split into first light in a first polarization state and second light in a second polarization state. The illumination optical system guides the first light to the first display and guides the second light to the second display. The first projection optical system projects the image displayed on the first display with the first light, and the second projection optical system projects the image displayed on the second display with the second light.