Solid-State Light Source Arrangement for Uniform Illumination
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Solution Overview
Problem
In projection display apparatuses using solid-state light sources with different directivities, such as red, green, and blue LEDs, the uneven dispersion angles lead to color shading and reduced light use efficiency due to the difficulty in equalizing the directivities of the light beams, resulting in uneven luminance and dispersion angle distributions across the illuminated surface.
Innovation Solution
The illumination apparatus incorporates a specific arrangement of solid-state light sources and an optical unit, where the distance from the arrangement surface to the light-entering surface of the optical unit is adjusted to reduce the dispersion angle difference between light beams of varying directivities, using a tapered rod integrator with distinct light-entering surfaces for each color, and a dent portion with a reflection surface to direct light beams with large dispersion angles away from the optical unit, thereby reducing color shading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If solid-state light sources with different directivities (red, green, blue LEDs) are used to achieve color display, then color rendering is improved, but uniformity of illumination and dispersion angle distribution deteriorates
Solution Approach 1:
The patent applies local quality by providing different distance arrangements for different color light sources. Specifically, light sources with different directivities (red, green, blue LEDs) are positioned at different distances from the optical unit, with each color having its optimized distance to compensate for inherent directivity differences. This localized adjustment ensures uniform illumination distribution across all colors while maintaining color rendering capabilities.
2Loss of energy
If the distance between light source and optical unit is reduced to improve light use efficiency, then light use efficiency is improved, but the ability to equalize dispersion angles deteriorates
Solution Approach 1:
The patent applies parameter changes by systematically varying the distance parameter for each light source based on its directivity characteristics. Each color LED is positioned at a specific distance from the optical unit that optimizes both light use efficiency and dispersion angle equalization. This parameter optimization allows the system to achieve uniform illumination while maximizing the utilization of light from each source.
3Illumination intensity
If molded lenses or photonic crystals are used to improve directivity of light beams, then directivity is improved, but the difficulty of equalizing directivities among different colors increases
Solution Approach 1:
The patent extracts the directivity control function from complex optical elements (molded lenses, photonic crystals) and implements it through a simpler geometric arrangement. Instead of using additional optical components for each color, the invention uses the spatial arrangement (distance from optical unit) to achieve directivity equalization. This extraction simplifies the overall system while maintaining the ability to control and equalize directivity across different colors.
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 effectively suppresses color shading and enhances light use efficiency by aligning the dispersion angles of light beams entering the optical unit, ensuring uniform illumination and improved image quality across the projected image.
Implementation Method 1
an optical unit configured to reduce the dispersion angle of light beams emitted from the solid-state light sources
Implementation Method 2
a tapered rod integrator configured to lead, to a display panel, light beams of the respective colors emitted from the plurality of solid-state light sources
Data Source
AI summary
An illumination apparatus includes; a first solid-state light source, a second solid-state light source, a first arrangement member provided with a first arrangement surface, a second arrangement member provided with a second arrangement surface, an optical unit configured to reduce a dispersion angle of a light beam. The first solid-state light source emits a light beam having a first directivity. The second solid-state light source emits a light beam having a second directivity greater than the first directivity. A distance from the second arrangement surface to the second light-entering surface is longer than a distance from the first arrangement surface to the first light-entering surface.