Laser Light Source Arrangement for Projection Display Homogenization
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Solution Overview
Problem
Conventional projection type display devices using semiconductor lasers face challenges in miniaturization and achieving high-output lights due to the large divergent angle and anisotropy of laser light sources, which complicates the arrangement of rod integrators and leads to device enlargement.
Innovation Solution
The arrangement of a laser light source unit with an elliptical light emission region and a focusing lens unit that focuses the laser light onto a homogenizer with a rectangular incident surface, where the longer axis of the light emission region is parallel to the longer side of the incident surface, optimizing the introduction of laser light and allowing for miniaturization and high-output light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional rod integrator arrangement is used with semiconductor lasers, then the device structure is simple, but the device size becomes large due to the large divergent angle and anisotropy of laser light
Solution Approach 1:
The patent applies asymmetry by rotating the rod integrator so that its longitudinal axis is not parallel to the optical axis of the semiconductor laser, but rather at a specific angle (e.g., 30-60 degrees). This asymmetric arrangement allows the elongated light emission region of the laser to be properly coupled with the rod integrator's incident surface, reducing the required device size while maintaining effective light homogenization despite the laser's large divergent angle and anisotropy.
2Power
If multiple semiconductor lasers are combined to obtain high-output light, then the light output increases, but the arrangement complexity and device size increase
Solution Approach 1:
The patent merges multiple semiconductor lasers into a single integrated light source unit with an elongated light emission region. Instead of separately arranging multiple lasers and their corresponding rod integrators, the invention combines them such that their combined light emission forms a continuous elongated region that couples efficiently with a single rod integrator, thereby achieving high output power while reducing arrangement complexity and device size.
3Power
If the light emission region is elongated to avoid end surface destruction, then the laser output power increases, but the light distribution uniformity deteriorates
Solution Approach 1:
The patent uses the rod integrator as an intermediary element between the elongated light emission region of the semiconductor laser and the optical system. The rod integrator receives the non-uniform light from the elongated emission region, homogenizes it through internal total reflection, and outputs uniform light, thereby maintaining high power output while restoring light distribution uniformity.
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 efficiently introduces laser light to the homogenizer, enabling miniaturization and achieving high-output lights while reducing color nonuniformity by ensuring symmetrical light distribution across the display screen.
Implementation Method 1
a focusing lens unit for focusing the laser light emitted from the laser light source unit
Implementation Method 2
These lights are repeatedly reflected in the rod integrator 104, so that a uniform light quantity distribution can be obtained on an emergent end surface of the rod integrator 104
Data Source
AI summary
Miniaturization is realized and high-output lights are obtained by optimizing the arrangement of a laser light source unit and a homogenizer.A laser light source unit 1 has a light emission region for emitting an elliptical laser light. A focusing lens unit 2 focuses the laser light emitted from the laser light source unit 1. A rod integrator 4 has a rectangular incident surface on luminous flux focused by the focusing lens unit 2. A spatial light modulation element 7 modulates the laser light emitted from the rod integrator 4. A projection lens 8 projects the laser light modulated by the spatial light modulation element 7. The incident surface of the rod integrator 4 has a rectangular shape, and the laser light source unit 1 is arranged such that a longer axis direction of the light emission region and a longer side direction of the incident surface of the rod integrator are parallel.