Projector Polarization Conversion Unit for Light Efficiency
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Solution Overview
Problem
Single-plate projectors using nonpolarized light sources suffer from reduced light use efficiency due to the polarization direction mismatch between the light source and the liquid crystal panel.
Innovation Solution
A projector design that includes a light source emitting non-linearly polarized light, a polarization conversion unit comprising a polarizing separator and a phase difference element to convert the light into predetermined linearly polarized light, and a light modulation device with a liquid crystal panel to modulate the light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an LED emitting nonpolarized light is used as a light source, then the light source can be simplified and cost-reduced, but light use efficiency deteriorates due to polarization direction mismatch with the liquid crystal panel
Solution Approach 1:
A polarization conversion unit is introduced as an intermediary component between the nonpolarized light source and the liquid crystal panel. This unit includes a polarizing separator and a phase difference element that work together to convert nonpolarized light into linearly polarized light with the correct polarization direction, thereby resolving the mismatch without requiring a complex polarized light source
Solution Approach 2:
The polarization state of the light is changed from nonpolarized to linearly polarized through the polarization conversion unit. The phase difference element adjusts the polarization direction parameter to match the transmission axis of the liquid crystal panel, ensuring optimal light transmission efficiency
2Loss of energy
If a reflective polarization element is provided as an incident-side polarization plate, then light use efficiency can be improved, but device complexity increases
Solution Approach 1:
The polarization conversion function is segmented into two distinct components: a polarizing separator that separates polarized light components and a phase difference element that aligns polarization directions. This segmentation allows each component to perform its specific function efficiently, achieving the desired light use efficiency while keeping the overall structure manageable and not excessively complex
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 enhances light use efficiency by aligning the polarization direction of the light source with the liquid crystal panel, reducing the need for additional polarization plates and improving image quality.
Implementation Method 1
a polarizing separator configured to separate the first light into second light and third light based on polarized light components
Implementation Method 2
a reflection element configured to reflect the third light made incident from the polarizing separation element toward the superimposing optical system
Implementation Method 3
a phase difference element configured to align polarization directions of the second light and the third light
Data Source
AI summary
A projector of the present disclosure includes a light source configured to emit first light, which is non-linearly polarized light, a polarization conversion unit configured to convert the first light into predetermined linearly polarized light, a light modulation device including a liquid crystal panel which modulates the predetermined linearly polarized light, and a superimposing optical system configured to superimpose the predetermined linearly polarized light on the liquid crystal panel. The polarization conversion unit includes a polarizing separator configured to separate the first light into second light and third light and a phase difference element configured to align polarization directions of the second light and the third light with the predetermined linearly polarized light. The polarizing separator includes a polarizing separation element and a reflection element, the polarizing separation element is provided in a tilted state with respect to a principal ray of the first light and separates the first light by reflecting a first linearly polarized light component in the first light toward the superimposing optical system as the second light and transmitting, as the third light, a second linearly polarized light component in the first light, and the reflection element reflects the third light made incident from the polarizing separation element toward the superimposing optical system.