Asymmetric Lens Module for Projection Apparatus Light Utilization
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Solution Overview
Problem
Conventional projection apparatuses suffer from light loss due to the rectangular shape of digital micro-mirror devices (DMDs) and lens cells, leading to inefficient light utilization, especially with widescreen displays, where the short side of the lens cell has a small effective light receiving angle, causing crosstalk and brightness interference.
Innovation Solution
A projection apparatus with a lens module that has unequal refractive powers along different directions, shaping the illumination beam to match the rectangular active surface of the light valve, increasing the f-number along the short side and reducing crosstalk loss by optimizing the lens design to ensure more light is irradiated on the DMD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the lens cell is designed with a rectangular shape to match the DMD, then the light spot uniformity is improved, but the effective light receiving angle along the short side becomes excessively small, causing light loss
Solution Approach 1:
The patent applies local quality by designing the lens cell with different effective light receiving angles in different directions. Specifically, the lens cell has a first effective light receiving angle in a direction parallel to the long side and a second effective light receiving angle in a direction parallel to the short side, where the second angle is designed to be larger than the first angle. This asymmetric design allows the lens cell to accommodate the rectangular DMD shape while ensuring sufficient light receiving capability along the short side, thereby reducing light loss and improving overall light utilization efficiency.
2Ease of operation
If the light beam enters the lens cell at an angle outside the effective light receiving angle range, then the propagating direction is deviated, but this causes crosstalk and brightness interference leading to light loss
Solution Approach 1:
The patent applies parameter changes by modifying the effective light receiving angle parameters of the lens cell. The lens cell is designed with specific effective light receiving angles in different directions (first angle parallel to the long side, second angle parallel to the short side), where the second angle is deliberately made larger than the first angle. This parameter optimization ensures that the lens cell can accept light beams within an appropriate angle range without causing crosstalk or brightness interference, thereby reducing light loss while maintaining beam shaping capability.
3Adaptability or versatility
If the lens unit has a 16:9 aspect ratio to match widescreen displays, then the display format is optimized, but the short side becomes excessively short, reducing the effective light receiving angle and causing more light loss
Solution Approach 1:
The patent applies local quality by designing the lens cell with different effective light receiving angles in different directions. Specifically, the lens cell has a first effective light receiving angle in a direction parallel to the long side and a second effective light receiving angle in a direction parallel to the short side, where the second angle is designed to be larger than the first angle. This asymmetric design allows the lens cell to accommodate the rectangular DMD shape while ensuring sufficient light receiving capability along the short side, thereby reducing light loss and improving overall light utilization efficiency.
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 solution enhances light utilization efficiency by reducing crosstalk loss from 15.5% to 7.2% and increasing light utilization from 55.6% to 63.8%, effectively addressing the inefficiencies in conventional projection systems.
Implementation Method 1
A refractive power of the lens module along a first direction is not equal to a refractive power of the lens module along a second direction
Data Source
AI summary
A projection apparatus includes a light source, a light valve, a light uniforming device, and a lens module. The light source provides an illumination beam. The light valve on a transmission path of the illumination beam converts the illumination beam into an image beam. The light valve has an active surface with a rectangular shape. The light uniforming device is between the light source and the light value. The lens module is between the light uniforming device and the light value. A refractive power of the lens module along a first direction is different from a refractive power of the lens module along a second direction. An f-number of the illumination beam along a direction parallel to a long side of the active surface of the light valve is greater than an f-number thereof along a direction parallel to a short side of the active surface of the light valve.