Projection Illumination System Green Light Purity and Efficiency
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Solution Overview
Problem
Current projection devices using LED light sources face inefficiencies in green light emission, leading to impure green light and a reduced color gamut due to the use of blue LEDs exciting yellow-green phosphors, resulting in a yellowish color shift and inadequate color performance for display applications.
Innovation Solution
An illumination system comprising a first and second light-emitting unit, dichroic elements, and a control unit that adjusts current ratios to form a high-performance mode and high-chroma mode, allowing for precise control of green light composition by combining pure green, red, and blue light beams to optimize color performance and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If blue LEDs and yellow-green phosphors are used to generate green light, then light efficiency is improved, but green light purity deteriorates causing yellowish color shift
Solution Approach 1:
The green light source is segmented into two independent pathways: one using blue LED excitation of yellow-green phosphor for high efficiency, and another using direct green LED for high purity. These segmented pathways are then combined through optical components to achieve both efficiency and purity simultaneously.
Solution Approach 2:
The patent merges the output from two different light generation mechanisms (phosphor-converted blue LED and direct green LED) into a single combined green light beam. This merging allows the system to leverage the advantages of both approaches while compensating for their individual limitations.
2Manufacturing precision
If green light purity is improved using direct green LEDs, then color gamut is improved, but light efficiency deteriorates
Solution Approach 1:
The system segments the green light generation into two parallel channels with different characteristics. The direct green LED channel provides high purity light, while the phosphor-converted channel provides high efficiency light. By segmenting the function, both requirements can be met simultaneously.
Solution Approach 2:
The system changes the parameters of green light generation by using two different mechanisms with complementary characteristics. By adjusting the contribution ratio of each channel through current control, the system can optimize the balance between purity and efficiency based on application requirements.
3Device complexity
If single green LED is used, then device complexity is reduced, but color performance deteriorates due to insufficient green light efficiency
Solution Approach 1:
The patent combines multiple light-emitting elements (blue LED, yellow-green phosphor, and green LED) into a unified light source assembly. This merging approach achieves superior color performance by leveraging the complementary strengths of different light generation mechanisms while maintaining integrated control.
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 system effectively adjusts the green light portion to meet both efficacy and color performance requirements, enabling the projection device to switch between modes to achieve high brightness or color accuracy, thus addressing the limitations of existing technologies.
Implementation Method 1
The first light-emitting element provides a first sub-light beam, and the second light-emitting element provides a second sub-light beam
Implementation Method 2
The first dichroic element is located on a transmission path of the second light beam and the third light beam. The second dichroic element is located on a transmission path of the first sub-light beam, the second sub-light beam, the second light beam, and the third light beam
Data Source
AI summary
An illumination system, a projection device, and a projection control method are provided. The illumination system includes a first light-emitting unit, a second light-emitting unit, a third light-emitting unit, a first dichroic element, a second dichroic element, and a control unit. The first light-emitting unit includes a first light-emitting element and a second light-emitting element. The control unit is electrically connected to the first light-emitting unit and configured to switch the illumination system between a high-performance mode and a high-chroma mode, wherein when the illumination system is in the high-performance mode, the control unit controls a current ratio of the second light-emitting element to be greater than a current ratio of the first light-emitting element, and when the illumination system is in the high-chroma mode, the control unit controls the current ratio of the second light-emitting element to be less than the current ratio of the first light-emitting element.