Projection Lens Miniaturization via Light-Transmitting Optical Element
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Solution Overview
Problem
Current projection systems face challenges in achieving high resolution and miniaturization due to the design complexities and space constraints within the light modulation assembly, particularly in reducing the distance between the digital micromirror device (DMD) and the projection lens, which affects the back focal length and overall volume of the apparatus.
Innovation Solution
The projection apparatus incorporates a light-transmitting optical element located between the prism group and the DMD, allowing for a reduced distance between the DMD and the projection lens, and optimizing the placement of the prism group to minimize the volume and complexity of the light modulation assembly, thereby enabling the projection of high-definition images such as 4K or 8K resolutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the DMD and the projection lens is reduced to achieve miniaturization, then the volume of the apparatus is reduced, but the back focal length becomes shorter which affects image projection quality
Solution Approach 1:
A light-transmitting optical element is introduced as an intermediary component between the prism group and the DMD. This element enables the optical system to achieve effective projection with a reduced physical distance between the DMD and projection lens, thereby solving the contradiction between miniaturization and back focal length requirements
Solution Approach 2:
The patent reconfigures the optical path by positioning the light-transmitting optical element in a specific spatial relationship with the prism group and DMD. This dimensional rearrangement allows the system to achieve the necessary optical path length while reducing the linear distance between key components, effectively addressing the volume-back focal length trade-off
2Manufacturing precision
If the prism group is repositioned to optimize the optical path, then the resolution and miniaturization are improved, but the design complexity of the light modulation assembly increases
Solution Approach 1:
The patent integrates the light-transmitting optical element into the existing light modulation assembly structure, combining multiple functions into a unified configuration. This merging approach enables resolution improvement through optimized optical path while managing design complexity by consolidating components rather than adding separate systems
3Volume of moving object
If the projection lens size is reduced to achieve miniaturization, then the overall volume is decreased, but the ability to maintain effective image projection is compromised
Solution Approach 1:
The light-transmitting optical element serves as a mediator that enables a smaller projection lens to maintain effective image projection capability. By optimizing the optical path through this intermediary component, the system achieves miniaturization of the projection lens while preserving its projection effectiveness
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 enhances the resolution of projected images by allowing multiple projections of a single pixel, improves the miniaturization of the apparatus, and simplifies the design of the projection lens by reducing its size and volume, while maintaining effective image projection.
Implementation Method 1
The light-transmitting optical element is disposed in the housing and is located between the digital micromirror device and the prism group
Implementation Method 2
The prism group is disposed in the housing, and a laser inlet side of the lens group faces towards a first laser inlet side of the prism group
Implementation Method 3
The digital micromirror device is fixed with the housing, and a reflecting surface of the digital micromirror device faces towards a first laser-exit side of the prism group
Implementation Method 4
The lens group is disposed in the housing, and a laser inlet side of the lens group faces towards the first opening
Data Source
AI summary
A projection apparatus includes a housing, a laser source, a projection lens, and a light modulation assembly. The housing includes a first opening and a second opening, a laser-exit side of the laser source faces towards the first opening, and a laser inlet side of the projection lens faces towards the second opening. The light modulation assembly includes a lens group, a prism group, a digital micromirror device, and a light-transmitting optical element. A second laser-exit side of the prism group faces towards the second opening, and an orthogonal projection of the laser inlet side of the projection lens on the prism group is within a region where the second laser-exit side of the prism group is located. The light-transmitting optical element is disposed in the housing and is located between the digital micromirror device and the prism group.