Eccentric Collimating Lens Micro Projector Volume Reduction
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Solution Overview
Problem
Current micro projector designs face challenges in reducing overall structure volume, leading to increased costs and difficulties in appearance structural design, and suffer from poor color uniformity due to differing brightness of red, blue, and green light with different polarization directions in laser light sources.
Innovation Solution
The use of an eccentric-collimating lens to deflect the optical path and a half-wave plate to address the issues of structure volume and color uniformity, respectively, by optimizing the optical path and polarization of light beams within the projection apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional coating process is used on optical elements, then the manufacturing process is simple, but the transmittance of light beam in S-polarization direction is not the same as in P-polarization direction, resulting in poor color uniformity
Solution Approach 1:
The patent applies a multi-layer coating with specific refractive indices and thicknesses on the light receiving surface of the optical element. By precisely controlling the optical parameters (refractive index, layer thickness) of each coating layer, the system achieves equal transmittance for both S-polarization and P-polarization light beams, thereby improving color uniformity while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses a composite multi-layer coating structure consisting of multiple layers with different refractive indices. This composite coating approach allows the system to simultaneously satisfy the optical requirements for both polarization directions, achieving color uniformity improvement without overly complicating the manufacturing process
2Device complexity
If conventional optical elements are used in the projector, then the optical path is straightforward, but the structure volume cannot be reduced, increasing cost and making appearance structural design difficult
Solution Approach 1:
The patent employs an eccentric collimating lens that introduces a controlled inclination angle between the optical axis and the light receiving surface. This dimensional change in the optical path configuration allows the system to reduce the overall projector structure volume while maintaining effective optical functionality, thereby lowering cost and improving appearance design freedom
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 approach reduces the system structure volume, lowers costs, and improves the degree of freedom in structural design while ensuring better color uniformity and brightness consistency of the image light beam.
Implementation Method 1
an optical structure of a micro projector mainly adopts light emitting diodes or laser diodes that may generate light beams of different colors as high brightness light sources of the projector. An image light beam is projected out of the projector by a projection lens through optical elements.
Implementation Method 2
since a conventional coating process may not achieve an effect that a transmittance of light beam in an S-polarization direction is the same as a transmittance thereof in a P-polarization direction, one of the polarization directions have a higher transmittance
Data Source
AI summary
A projection apparatus including a light source module, an eccentric-collimating lens, a prism lens group, a light valve and a projection lens is provided. The light source module is configured to provide an illumination light beam. The eccentric-collimating lens is disposed between the light sources and the light valve on a transmission path of the illumination light beam. The light valve is configured to convert the illumination light beam into an image light beam. The projection lens is configured to project the image light beam out of the projection apparatus. A first included angle between a first transmission direction of the illumination light beam incident on the eccentric-collimating lens and a central axis of the eccentric-collimating lens is greater than 0. The first transmission direction and a second transmission direction of the image beam exiting from the light valve are perpendicular to each other.