Laser Light Spot Aspect Ratio via Off-Focus Positioning
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Solution Overview
Problem
Conventional laser-based light sources require complex adjustments and multiple groups to achieve a rectangular light spot, increasing assembly costs and inefficiency due to their elliptical Gaussian light distribution, which does not match the aspect ratios needed in display technologies.
Innovation Solution
A light-emitting device with a laser unit and collimating lens where the laser unit is positioned off-focus, allowing for a rectangular light-emitting surface and adjusted divergence angles to form a light spot with a predetermined aspect ratio, reducing the need for multiple groups and adjustments, using a focusing lens to combine light from multiple units into a single or fewer non-overlapping spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If multiple laser units are used to form a rectangular light spot, then the light spot aspect ratio can be matched to display requirements, but the assembly complexity and adjustment requirements increase significantly
Solution Approach 1:
The patent changes the key parameter of the laser unit by positioning it away from the focal point of the collimating lens. This parameter change transforms the light distribution from an elliptical Gaussian pattern to a rectangular pattern with controllable aspect ratio, eliminating the need for multiple laser units and complex assembly adjustments
Solution Approach 2:
Instead of using multiple laser units arranged in a specific pattern to create a rectangular light spot, the patent inverts the approach by using a single laser unit with modified optical parameters (positioned off-focus) to directly generate the rectangular light spot, thereby simplifying the system
2Shape
If multiple laser units are used to form a rectangular light spot, then the light spot aspect ratio can be matched to display requirements, but the assembly time and cost increase
Solution Approach 1:
The patent merges the functions of multiple laser units into a single laser unit system. By positioning one laser unit away from the focal point, it can simultaneously achieve both collimation and rectangular light spot formation, consolidating what previously required multiple separate units and their associated alignment procedures into a single integrated system
3Stability of the object's composition
If laser units are positioned at the focal point of the collimating lens, then the light can be properly collimated, but the light spot becomes elliptical and does not match display aspect ratios
Solution Approach 1:
The patent changes the position parameter of the laser unit from the focal point to an off-focus position. This parameter change simultaneously maintains adequate collimation while transforming the light spot shape from elliptical to rectangular with controllable aspect ratio, resolving the contradiction between collimation quality and light spot shape
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 approach simplifies the assembly process by allowing a single or fewer groups of laser units to form a rectangular light spot, reducing adjustment requirements and enhancing assembly efficiency while maintaining high light spot quality.
Implementation Method 1
a collimating lens corresponding to the laser unit, wherein a collimating surface of the collimating lens is coincident with a light emitting surface of the laser unit, wherein the collimating lens collimates the laser light emitted by the laser unit onto a focusing lens
Implementation Method 2
a focusing lens, wherein the collimating lens collimates the laser light emitted by the laser unit onto the focusing lens, and the focusing lens focuses the laser light from the collimating lens onto a target plane to form a predetermined light spot
Data Source
Figure 1a~2a
Figure 2b~3a
Figure 3b~4b
AI summary
A light-emitting device and a related projection system. Light-emitting devices (300, 400) comprise: a light source unit (1) and focusing lenses (330, 430). The light source unit (1) comprises laser units (310, 410) and collimating lenses (320, 420) corresponding to the laser units (310, 410). The light-emitting surface of the laser units (310, 410) is a rectangle, and the light divergence angle of laser passing through the cross-section of the long side of the rectangle is smaller than the light divergence angle of same passing through the cross-section of the short side of the rectangle. The collimating lenses (320, 420) are used for focusing the laser from the laser units (310, 410) on a target surface to form a predetermined light spot. The laser units (310, 410) are located on the light axis of the collimating lenses (320, 420) in a predetermined position deviating from the focal point thereof, so that the predetermined light spot has a predetermined length-width ratio. The light-emitting device and the related projection system have the advantages of relatively small regulation quantity and relatively high assembly efficiency.