Retardation Plate Polarization Control for Projection Light Sources
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Solution Overview
Problem
Existing projection display apparatuses using solid-state light sources face challenges in efficiently collecting and combining light to achieve a low-cost, high-luminance, and long-operating-life solution, particularly in maintaining polarization properties and achieving desired white balance.
Innovation Solution
The use of a retardation plate to convert linearly polarized light into circularly polarized light, combined with a dichroic mirror and reflection plate, effectively separates and collects light, ensuring a constant ratio of p-polarization and s-polarization components, and a half-wave plate adjusts polarization directions to control light separation, resulting in a small, efficient, and inexpensive light source device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retardation plate is disposed at a point of incidence of collected light and divergent light between the condenser element and the reflection plate, then the polarization direction is changed to make the ratio of p-polarization and s-polarization components constant, but the device complexity increases
Solution Approach 1:
The retardation plate serves as an intermediary optical element that introduces a phase difference between p-polarization and s-polarization components. By positioning it at the specific point of incidence between the condenser element and reflection plate, the plate mediates the light path to achieve constant polarization ratio without requiring complex adjustment mechanisms
Solution Approach 2:
The retardation plate changes the polarization state parameters of the light by introducing a controlled phase difference. This parameter change transforms the light from having variable polarization ratios to having constant p-polarization and s-polarization component ratios, simplifying the overall system control
2Illumination intensity
If light from solid-state light source is collected and combined to achieve high luminance, then the illumination intensity improves, but the loss of energy increases due to inefficient light collection
Solution Approach 1:
The light collection system is segmented into multiple functional components: condenser element for initial light gathering, retardation plate for polarization control, and reflection plate for final redirection. Each segment optimizes a specific aspect of light collection, reducing overall energy loss while achieving high luminance
Solution Approach 2:
The system utilizes polarization dimension in addition to spatial light collection. By controlling the polarization state through the retardation plate, the system efficiently directs light in multiple directions simultaneously, reducing energy loss that would occur with single-dimension collection methods
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 enables the creation of a small, cost-effective light source device that provides bright, high-luminance projection display apparatus with stable white balance and extended operational life by efficiently combining blue, green, and red light into white light, addressing previous inefficiencies in light collection and polarization management.
Implementation Method 1
a retardation plate that converts linearly polarized light into circularly polarized light
Implementation Method 2
a retardation plate that changes a polarization direction of light from the solid-state light source
Implementation Method 3
a dichroic mirror that separates the light from the retardation plate according to the polarization direction
Implementation Method 4
a condenser element that collects light from the solid-state light source
Implementation Method 5
a reflection plate
Data Source
AI summary
A first light source device includes: a solid-state light source; a condenser element that collects light from the solid-state light source; a retardation plate that converts linearly polarized light into circularly polarized light; and a reflection plate, wherein the retardation plate is disposed at a point of incidence of collected light and divergent light between the condenser element and the reflection plate. A second light source device includes: a solid-state light source; a retardation plate that changes a polarization direction of light from the solid-state light source to make a ratio of polarization and s-polarization components of the light constant under control; and a dichroic mirror that separates the light from the retardation according to the polarization direction, wherein the retardation plate is disposed at a point of incidence of one of collected light and divergent light between the solid-state light source and the dichroic mirror.