Light Source Unit In-Plane Uniformity via Light Distribution Adjusting Member
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Solution Overview
Problem
Conventional light source units for projectors using blue laser emitting devices and green luminescent materials suffer from uneven in-plane uniformity of light emission, leading to luminance inconsistencies in projected images.
Innovation Solution
A light source unit with an excitation light source and a light distribution adjusting member, such as a light tunnel, where the excitation light is incident at a predetermined angle, enhancing the in-plane uniformity of light by multiple reflections within the tunnel before illuminating a luminescent wheel with annular green and diffuse reflection areas, and a dichroic mirror to manage red, green, and blue wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue laser emitting device and green luminescent material are used as light source, then high intensity light can be obtained, but in-plane uniformity of light emission becomes uneven
Solution Approach 1:
A light distribution adjusting member is introduced as an intermediary component between the excitation light source and the luminescent material. This member receives the excitation light and redistributes it uniformly across the luminescent material surface through internal reflection and refraction, ensuring even illumination without compromising the high intensity output of the blue laser and green luminescent material combination
Solution Approach 2:
The patent changes the angular parameter of light incidence by disposing the excitation light source at a predetermined angle relative to the luminescent material. This angular adjustment, combined with the light distribution adjusting member, transforms the uneven point-source illumination into a more uniform distributed illumination pattern, resolving the in-plane uniformity issue while maintaining high intensity
2Device complexity
If excitation light is shone directly on luminescent material, then simple structure is maintained, but in-plane uniformity of luminous light becomes poor
Solution Approach 1:
The light distribution adjusting member serves as a mediator that adds minimal structural complexity while significantly improving in-plane uniformity. The member is positioned between the excitation light source and luminescent material, using optical principles to redistribute light evenly without requiring complex mechanical adjustments or multiple light sources
Solution Approach 2:
The patent addresses the uniformity problem by transitioning from direct point-source illumination to a distributed illumination pattern through the light distribution adjusting member. This member effectively adds a spatial dimension to light distribution, transforming the illumination from a one-dimensional point contact to a two-dimensional uniform coverage across the luminescent material surface
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 significantly improves the in-plane uniformity of light emission, enabling the projection of images with consistent luminance and reduced color unevenness, resulting in a high-intensity light source unit that produces images with minimal luminance and color irregularities.
Implementation Method 1
a light distribution adjusting member on which excitation light from the excitation light source is incident... by multiple reflections within the tunnel
Implementation Method 2
a luminescent material which emits luminous light of a different wavelength from that of the excitation light by the excitation light which passes through the light distribution adjusting member being shone on thereto
Implementation Method 3
a dichroic mirror to manage red, green, and blue wavelengths
Data Source
AI summary
The invention includes an excitation light source, a light distribution adjusting member on which excitation light from the excitation light source is incident, and a luminescent material which emits luminous light of a different wavelength from that of the excitation light by the excitation light which passes through the light distribution adjusting member being shone on thereto, wherein the excitation light source is disposed so that the excitation light is incident on a light incident surface of the light distribution adjusting member at a predetermined angle.