Projector Light Guide Layout for Blue Light Leakage Reduction
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Solution Overview
Problem
Existing light source apparatuses for projectors using phosphors face inefficiencies due to blue light leakage through transparent rods, disrupting the balance between yellow and blue light, leading to suboptimal white light production.
Innovation Solution
A light source apparatus with a first light source emitting excitation light, a wavelength converter, optical layers, and a parallelizing system to guide and parallelize light, ensuring efficient use of blue and yellow light by minimizing leakage and maintaining balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If blue light emitting diodes are disposed to face a side surface of a transparent rod with blue light entering via the side surface, then the structure is simple, but blue light leaks out through side surfaces causing decrease in blue light usage efficiency
Solution Approach 1:
The patent changes the entry dimension of blue light from side surface (lateral direction) to end surface (axial direction) of the transparent rod. By disposing the blue light emitting diodes to face the end surface and using a parallelizing system to make blue light enter parallel to the axis, the patent prevents blue light from incident on side surfaces at angles smaller than critical angle, thereby eliminating leakage through side surfaces while maintaining structural simplicity.
2Ease of manufacture
If blue light enters the transparent rod via side surface, then the configuration is straightforward, but the balance between yellow light and blue light deteriorates due to blue light leakage
Solution Approach 1:
The patent modifies the light entry configuration from side surface to end surface, making blue light enter parallel to the rod axis. This dimensional change ensures blue light travels through the rod without incident on side surfaces, preventing leakage and maintaining the intended balance between yellow light (from phosphor conversion) and blue light (direct transmission).
Solution Approach 2:
The patent introduces a parallelizing system as an intermediary component between the blue light emitting diodes and the transparent rod. This system collimates the blue light before it enters the rod, ensuring parallel incidence that prevents side surface leakage. The parallelizing system acts as a mediator that achieves both ease of manufacture and light balance stability.
3Stability of the object's composition
If blue light has many angular components incident on side surfaces at angles smaller than critical angle, then light distribution is uniform, but a large amount of blue light leaks out causing decrease in efficiency
Solution Approach 1:
The patent eliminates the angular component issue by changing the light entry geometry. Instead of blue light incident on side surfaces with various angles, the patent makes blue light enter through the end surface parallel to the axis, traveling through the rod without encountering side surfaces. This dimensional change simultaneously achieves uniform light distribution and prevents leakage.
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 apparatus enhances the efficiency of white light production by reducing blue light leakage and maintaining the balance between yellow and blue light components, allowing for improved projector performance.
Implementation Method 1
there has been a proposed light source apparatus using fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light emitted from a light emitter
Implementation Method 2
a first optical layer disposed between the first light source and the wavelength converter and configured to transmit the first light and reflect the second light
Data Source
AI summary
A light source apparatus according to an aspect of the present disclosure includes a first light source configured to output first light; a wavelength converter configured to convert the first light into second light; a first optical layer configured to transmit the first light and reflect the second light; a second light source configured to output third light; a light guide configured to guide the second light and the third light; a parallelizing system configured to parallelize the third light; and a second optical layer configured to transmit the third light and reflect the second light. The wavelength converter has a first surface and a second surface that face opposite sides, and a third surface that intersects with the first surface and the second surface. The first light is incident on the third surface of the wavelength converter via the first optical layer. The second light travels through the light guide and exits out of a region on the first surface side of the light guide. The third light is parallelized by the parallelizing system, enters a region on the second surface side of the light guide via the second optical layer, travels through the light guide in the direction parallel to the third surface, and exits out of the region of the light guide, which is a region facing the first surface.