Laser Diode Collimating Lens Shift for Phosphor Beam Shaping
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Solution Overview
Problem
Existing light source apparatuses for time divisional projectors face challenges in achieving efficient emission efficiency of phosphors due to high light intensity and difficulty in obtaining desired beam shapes, as the location of light condensed positions is limited by the small diameter of parallel light emitted from collimating lenses.
Innovation Solution
The light source apparatus employs a configuration where collimating lenses are shifted relative to the optical axis of laser diodes, allowing light to be condensed onto different positions on a phosphor wheel, thereby reducing light intensity and enabling the attainment of desired beam shapes with specific sizes and aspect ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the location of light condensed position is changed by varying distance between laser diodes and collimating lenses, then the beam shape can be adjusted, but the light intensity at condensed position becomes too high which reduces phosphor emission efficiency
Solution Approach 1:
The patent introduces a lateral shift dimension by displacing the optical axis of the collimating lens relative to the laser diode in a direction perpendicular to the optical axis of emitted light. This dimensional change allows the condensed light position to be moved laterally on the phosphor surface, distributing the high light intensity over a larger area and reducing peak intensity, thereby maintaining phosphor emission efficiency while achieving desired beam shapes.
2Stability of the object's composition
If the optical axis of collimating lens is aligned with laser diode, then the light condensed position is fixed, but the beam shape cannot achieve desired size or aspect ratio
Solution Approach 1:
The patent makes the system dynamically adjustable by introducing a variable lateral shift between the collimating lens optical axis and the laser diode optical axis. This dynamic adjustment mechanism allows the beam shape and condensed position to be adaptively controlled according to different requirements, while the underlying optical path remains stable and well-defined.
3Area of moving object
If collimating lens is positioned at focusing position, then light is condensed to a small diameter, but the light intensity becomes too high reducing phosphor efficiency
Solution Approach 1:
By introducing a lateral displacement between the collimating lens optical axis and laser diode optical axis, the patent moves the condensed light position to a location where the light distribution is more favorable. This dimensional change allows achieving an optimal balance between condensed area size and light intensity, preventing excessive concentration of light energy at a single point while maintaining efficient phosphor excitation.
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 enhances phosphor emission efficiency and allows for the adjustment of beam shapes, reducing light density and improving the projector's performance by efficiently utilizing the light emitted from the phosphor.
Implementation Method 1
a condenser lens which condenses lights emitted from the light sources
Implementation Method 2
it is possible to convert wavelength of a blue light from a laser diode into that of a green or red light by using phosphors
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
A light source apparatus 1 comprising: a plurality of light sources 10 each including a laser diode 12 and a collimating lens 13 which corresponds to said laser diode 12, a condenser lens 20 which condenses lights emitted from said light sources 10,and a phosphor wheel 30 having a phosphor 32, said phosphor wheel 30 transmitting a light which is emitted from said condenser lens 20, wherein at least in a part of said plurality of light sources 10, said collimating lens 13 and said laser diode 12 are placed with a first shift such that an optical axis of said collimating lens 13 is shifted from an optical axis of a light emitted from said laser diode 12 in the direction perpendicular to the optical axis of the emitted light 12, wherein said laser diodes 12 include a first laser diode 12A in which a direction of a short axis of a condensed shape thereof is placed in a first direction, and a second laser diode 12B in which a direction of a short axis of a condensed shape thereof is placed in a second direction which is different from the first direction, and wherein said collimating lens 13 which corresponds to said first laser diode 12A and said collimating lens 13 which corresponds to said second laser diode 12B are placed with a second shift in a direction of the optical axis of said collimating lens 13.