Wavelength-Selective Projector Optics for Color Reproducibility
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Solution Overview
Problem
Projectors using light emitting diodes face issues with decreased color reproducibility due to unwanted wavelength bands in the light emitted, particularly when fluorescent layers convert blue light into green and red light, resulting in intermediate color light that affects image quality.
Innovation Solution
A projector design incorporating a first light source apparatus with a wavelength converter, a light guide, a filter, and a light modulator to separate and manage different wavelength bands, enhancing color reproducibility by removing unwanted intermediate colors and increasing optical intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light emitter and wavelength converter are used to generate multiple color light, then the projector can output white light containing multiple color components, but unwanted intermediate color light with specific wavelength bands is generated that decreases color reproducibility
Solution Approach 1:
The patent extracts and removes the unwanted intermediate color light components (cyan light and yellow light) from the white light output using wavelength selective filters. The first filter removes cyan light (470-490nm) and the second filter removes yellow light (570-590nm), leaving only the desired blue, green, and red light components to ensure accurate color reproduction while maintaining brightness
Solution Approach 2:
The patent changes the wavelength distribution parameters of the output light by selectively transmitting and blocking specific wavelength bands. The filters are designed to transmit blue light (420-470nm), green light (490-570nm), and red light (590-680nm) while blocking the intermediate wavelength bands, thereby transforming the spectral composition to achieve both high brightness and accurate color reproduction
2Illumination intensity
If multiple wavelength bands are transmitted to increase brightness, then the projected image becomes brighter, but the color accuracy deteriorates due to intermediate color light interference
Solution Approach 1:
The patent extracts and removes the unwanted intermediate color light components (cyan light and yellow light) from the white light output using wavelength selective filters. The first filter removes cyan light (470-490nm) and the second filter removes yellow light (570-590nm), leaving only the desired blue, green, and red light components to ensure accurate color reproduction while maintaining brightness
Solution Approach 2:
The patent changes the wavelength distribution parameters of the output light by selectively transmitting and blocking specific wavelength bands. The filters are designed to transmit blue light (420-470nm), green light (490-570nm), and red light (590-680nm) while blocking the intermediate wavelength bands, thereby transforming the spectral composition to achieve both high brightness and accurate color reproduction
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 design improves color reproducibility and brightness of projected images by effectively managing and converting unwanted wavelength bands, resulting in a more vivid and durable projection system.
Implementation Method 1
a light converter that converts part of the first color light from the light emitter into second color light
Implementation Method 2
a first reflection surface having an inner surface configured to reflect the third color light incident via the first light incident end part
Implementation Method 3
a first filter disposed at a position facing a light exiting side of the first light guide and configured to transmit first-wavelength color light out of the third color light and reflect second-wavelength color light out of the third color light toward the first light guide
Data Source
AI summary
A projector includes a first light source apparatus including a first light emitter configured to emit first color light and a first wavelength converter configured to convert part of the first color light from the first light emitter into second color light, the first light source apparatus configured to output third color light containing the first color light and the second color light; a first light guide including a first light incident end part on which the third color light output from the first light source apparatus is incident, a first light exiting end part via which the third color light incident via the first light incident end part exits, and a first reflection surface having an inner surface configured to reflect the third color light incident via the first light incident end part; a first filter disposed at a position facing a light exiting side of the first light guide and configured to transmit first-wavelength color light out of the third color light and reflect second-wavelength color light out of the third color light toward the first light guide; a first light modulator configured to modulate the first-wavelength color light to form a projection image; and a projection lens configured to project the projection image in a form of an enlarged image.