Non-polarized dichroic mirrors for image display modules
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Solution Overview
Problem
Existing image display devices using dichroic prisms for combining light from organic electroluminescence panels suffer from low light utilization efficiency and stray light generation due to polarization characteristics, particularly affecting red light emission.
Innovation Solution
An image display module comprising three panels emitting non-polarized light in different wavelength regions (red, blue, and green) combined using dichroic mirrors with no polarization separation characteristics, optimizing the transmission and reflection properties to achieve equal to or greater than 50% light utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dichroic prism with polarization separation characteristics is used to combine light from organic EL panels, then the wavelength separation characteristics are improved, but the light utilization efficiency deteriorates to maximum 50%
Solution Approach 1:
The patent changes the key parameter of the dichroic mirror from having polarization separation characteristics to having no polarization separation characteristics. This parameter change allows the dichroic mirror to effectively separate wavelengths for non-polarized light from organic EL panels without discarding half the light based on polarization state, thereby resolving the contradiction between wavelength separation and light utilization efficiency
Solution Approach 2:
The patent creates a new type of dichroic mirror that copies the wavelength separation function of traditional dichroic mirrors but removes the polarization separation characteristic. This copied function is specifically adapted for non-polarized light sources, allowing full light utilization while maintaining wavelength separation capability
2Loss of energy
If a dichroic mirror without polarization separation characteristics is used to combine non-polarized light, then the light utilization efficiency is improved, but stray light is generated
Solution Approach 1:
The patent optimizes specific parameters of the dichroic mirror including the peak wavelength (630-680 nm for red region) and the spectral characteristics to achieve high reflection efficiency for red light while minimizing stray light generation. This parameter optimization allows the mirror to maintain sharp wavelength separation without the polarization limitation
Solution Approach 2:
The patent replaces the traditional polarization-based light separation mechanism with a wavelength-based separation mechanism using optimized dichroic mirrors. This substitution eliminates the need to filter out polarized components and instead directly separates wavelengths, improving light utilization while controlling stray light through precise optical design
3Loss of energy
If a dichroic mirror without polarization separation characteristics is used, then the light utilization efficiency for red light is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for the dichroic mirror including peak wavelength (630-680 nm) and transmission bandwidth (≥130 nm for green light) to balance manufacturing feasibility with performance requirements. These parameter specifications provide clear manufacturing targets that achieve high red light utilization efficiency while remaining practically producible
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 utilization efficiency for red light and reduces stray light, achieving improved display quality by using dichroic mirrors with specific peak wavelength ranges and optical resonators in the panels.
Implementation Method 1
a first dichroic mirror having no polarization separation characteristics, and a second dichroic mirror having no polarization separation characteristics
Implementation Method 2
a color combined prism configured to emit combined light combined from the first imaging light, the second imaging light, and the third light
Implementation Method 3
a first panel configured to emit first imaging light of a red wavelength region, a second panel configured to emit second imaging light in a blue wavelength region, a third panel configured to emit third imaging light of a green wavelength region
Data Source
AI summary
An image display module according to the present disclosure includes a first panel configured to emit first imaging light of a red wavelength region having no polarization characteristics, a second panel configured to emit second imaging light of a blue wavelength region having no polarization characteristics, a third panel configured to emit third imaging light of a green wavelength region having no polarization characteristics, and a color combined prism configured to emit combined light combined from the first imaging light, the second imaging light, and the third imaging light. The color combined prism includes a first dichroic mirror having no polarization separation characteristics, and a second dichroic mirror having no polarization separation characteristics, and a peak wavelength in the red wavelength region is equal to and greater than 630 nm and equal to or less than 680 nm.