Light Shielding Unit for Projection Display Color Balance
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Solution Overview
Problem
In projection type image display apparatuses using non-white illumination light, the balance of color components can differ between regions when a diaphragm is used, leading to potential image quality deterioration due to changes in color balance.
Innovation Solution
A light emitting device comprising a light source, a fluorescent substance, a fly-eye lens, and a light shielding unit with a diaphragm and filter configuration that adjusts the ratio of first and second wavelength components in illumination light, ensuring consistent color balance across different diaphragm states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a diaphragm is used to shield light in a projection type image display apparatus using non-white illumination light, then light shielding control is achieved, but color balance deteriorates due to regional differences in wavelength components
Solution Approach 1:
The patent divides the light shielding function into two separate components: a diaphragm for controlling light intensity and a filter for managing wavelength distribution. This segmentation allows independent optimization of each function - the diaphragm provides light shielding control while the filter maintains color balance by selectively transmitting or blocking specific wavelength regions, thereby resolving the contradiction between operational control and composition stability
Solution Approach 2:
The filter acts as an intermediary element between the light source and the diaphragm. It modifies the spectral composition of the illumination light before it reaches the diaphragm, ensuring that when the diaphragm shields light, the remaining light maintains proper color balance. This intermediary approach allows the diaphragm to perform its light control function without causing color balance deterioration
2Device complexity
If illumination light with different color component balance in each region is used, then device complexity is reduced, but image quality deteriorates when diaphragm is used
Solution Approach 1:
The patent applies local quality by positioning the filter at a specific location in the optical path where it can selectively modify the wavelength composition in different spatial regions. The filter is designed to address regional differences in color components locally, ensuring that each region of the illumination light maintains appropriate color balance even when the diaphragm is used, thus maintaining image quality without increasing overall 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
The solution effectively maintains color balance and image quality by shielding the appropriate wavelength components, minimizing changes in color temperature and component ratios between open and closed diaphragm states.
Implementation Method 1
a fluorescent substance on which the source light is incident and which excites fluorescent light having a second wavelength by the source light
Implementation Method 2
a filter that shields light having the second wavelength of the illumination light in the second region and transmits light having the first wavelength of the illumination light in the second region
Data Source
AI summary
A light emitting device includes a light source which emits source light having a first wavelength, a fluorescent substance which excites fluorescent light having a second wavelength by the source light and emits the source light and the fluorescent light as illumination light, a fly-eye lens, and a light shielding unit. In the illumination light, a first wavelength component in a first region which is a portion of a region in a cross-sectional view with respect to the traveling direction of the light is smaller than that in a second region which is a region other than the first region. The light shielding unit includes a diaphragm unit which shields the illumination light L and a filter which shields the light having the second wavelength of the illumination light in the second region and transmits the light having the first wavelength of the illumination light in the second region.