Rectangular Light Integration Rod Asymmetry for Projector Efficiency
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Solution Overview
Problem
Conventional projectors suffer from poor light utilization efficiency due to light loss and stray light issues caused by the shape of the light spot and the total internal reflection prism, leading to inefficiencies in projecting images.
Innovation Solution
The light integration rod is designed with a rectangular light incidence end and emission end, where the first long edge parallels the second short edge and the first short edge parallels the second long edge, allowing for modulation of the light spot shape to reduce light loss and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional rectangular light integration rod with aligned edges is used, then the structure is simple and easy to manufacture, but light loss occurs and light utilization efficiency deteriorates
Solution Approach 1:
The patent applies asymmetry by rotating the light integration rod 45 degrees relative to the projection lens optical axis, causing the rectangular light spot to become oval-shaped. This asymmetric orientation reduces light loss by optimizing the light spot geometry to better match the projection lens aperture, thereby improving light utilization efficiency while maintaining the simple rectangular structure of the light integration rod itself.
2Productivity
If the light spot shape is not modulated, then the structure remains simple, but light utilization efficiency deteriorates due to light loss and stray light overlap
Solution Approach 1:
The patent implements dynamics by enabling the light spot shape to be modulated through rotational adjustment of the light integration rod. The rod can be rotated to different angles (specifically 45 degrees) to change the light spot from rectangular to oval-shaped, allowing the system to adapt the light geometry to optimize performance without requiring complex additional optical elements.
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 design results in a more oval-like light spot with reduced light loss and minimized overlap with stray light, enhancing the overall light utilization efficiency of the projector.
Implementation Method 1
a light integration rod 120, a total internal reflection prism (TIR prism) 130
Implementation Method 2
The total internal reflection prism 130 has a total reflection surface 132 configured to reflect the illumination beam 112 to the digital micro-mirror device 140
Implementation Method 3
The digital micro-mirror device 140 is configured to convert the illumination beam 112 into an image beam 113
Implementation Method 4
The projection lens 150 is configured to project the image beam 113 onto a screen (not shown) thereby forming an image on the screen
Data Source
AI summary
A projector includes a light source, a light integration rod, a light valve, and a projection lens. The light source provides an illumination beam. The light integration rod has a light incidence end and a light emission end opposite to each other. Through the light incidence and emission ends, the illumination beam is emitted into and out from the light integration rod, respectively. Each of the light incidence end and the emission end is in a rectangular shape. The light incidence end has a first long edge and a first short edge. The light emission end has a second long edge paralleling to the first short edge and a second short edge paralleling to the first long edge. The light valve converts the illumination beam into an image beam. The projection lens is disposed on a transmission path of the image beam. A light integration rod is also provided.