Compact Illumination System Using Crosswise Dichroic Devices
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Solution Overview
Problem
Conventional projection devices using blue laser diodes and phosphor wheels require a large volume due to the need for multiple reflection mirrors and dichroic elements, leading to a bulky architecture.
Innovation Solution
The use of a crosswise arrangement of first and second dichroic devices, an actuation element, and a wavelength conversion device allows the excitation beam to pass through intervals between dichroic elements in one period and be reflected in another, eliminating the need for additional reflection members to wind around a circle of light paths, resulting in a more compact illumination system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional architecture with blue laser diode and phosphor wheel is used, then the projection device can generate required colors, but the volume of the projection device becomes relatively larger
Solution Approach 1:
The second dichroic device is divided into multiple dichroic elements arranged at intervals, creating separate optical paths for different wavelengths. This segmentation allows the excitation beam to be selectively reflected or transmitted based on wavelength, eliminating the need for additional reflection mirrors and reducing overall device volume.
Solution Approach 2:
The first and second dichroic devices are arranged crosswise (perpendicularly to each other), creating a two-dimensional spatial arrangement that optimizes light path routing. This dimensional arrangement allows the excitation beam to pass through intervals between dichroic elements in one period and be reflected in another period, eliminating the need for winding circular light paths.
2Ease of operation
If multiple reflection mirrors are used to configure the excitation beam, then the blue light can be transmitted to the filter wheel, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates unnecessary reflection mirrors from the conventional optical path. By using the crosswise arrangement of dichroic devices with intervals between dichroic elements, the system directly transmits or reflects the excitation beam without requiring additional reflection mirrors to wind the light path around in a circle.
Solution Approach 2:
The second dichroic device with multiple dichroic elements serves multiple functions: it selectively reflects specific wavelengths while transmitting others, and its interval structure allows the excitation beam to pass through in one period while being reflected in another period. This multi-functionality replaces what would otherwise require multiple separate optical elements.
3Ease of operation
If the excitation beam winds around a circle of light paths, then the blue light can reach the filter wheel, but the volume of the illumination system increases
Solution Approach 1:
Instead of winding the light path in a circular pattern, the patent inverts the approach by using a linear crosswise arrangement of dichroic devices. The excitation beam travels in a more direct path, passing through intervals between dichroic elements or being reflected by them, eliminating the need for circular winding and reducing illumination system volume.
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 reduces the overall volume of the projection device by eliminating unnecessary optical elements and enhancing efficiency, allowing for a smaller and more compact projection device.
Implementation Method 1
The wavelength conversion device is disposed on a transmission path of the excitation beam passing through the second dichroic device, so as to convert the excitation beam into a conversion beam
Implementation Method 2
The dichroic elements correspond to the excitation light sources respectively and are used for reflecting the excitation beam
Data Source
AI summary
An illumination system includes an excitation light source group, a first dichroic device, a second dichroic device, an actuation element, and a wavelength conversion device. The excitation light source group includes a plurality of excitation light sources. Each excitation light source provides an excitation beam. The first dichroic device configures the excitation beam to pass therethrough. The second dichroic device includes a plurality of dichroic elements which are arranged at intervals and reflect the excitation beam. The actuation element configures the excitation beam to pass through the second dichroic device in a first period through intervals between the dichroic elements, and configures the excitation beam to be reflected by the dichroic element in a second period. The wavelength conversion device converts the excitation beam into a conversion beam. The invention further provides a projection device having this illumination system.