Telecentric Projection Optics for Thin Enclosure Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional micromirror-based projection systems have larger 'form factor' enclosures due to constraints on Total Internal Reflection (TIR) Fresnel display screens and non-telecentric lenses, which result in substantial 'chin' and 'depth' dimensions, making them less competitive in the market compared to LCD and plasma displays.
Innovation Solution
A projection display system with a telecentric lens arrangement, aspheric lenses, and folding mirrors is used to minimize the 'chin' and 'depth' dimensions, incorporating a laser-based light source and a spatial light modulator to correct distortion and maintain high image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional micromirror-based projection systems use TIR Fresnel display screens and non-telecentric lenses, then the system can achieve projection display functionality, but the enclosure dimensions (chin and depth) become substantially larger
Solution Approach 1:
The patent transitions from non-telecentric to telecentric lens arrangement, changing the optical parameter configuration. This parameter change enables the system to achieve both compact enclosure dimensions and acceptable image quality by modifying how light rays are directed through the projection optics
Solution Approach 2:
The patent introduces folding mirrors to fold the optical path, effectively utilizing three-dimensional space to reduce the linear depth of the enclosure. By bending the light path in multiple dimensions rather than using a straight optical path, the system achieves compact form factor without sacrificing projection capability
2Length of stationary object
If the enclosure depth is reduced to make the system thinner, then the form factor is improved, but the optical path length available for projection is insufficient
Solution Approach 1:
The patent employs folding mirrors to create a folded optical path that extends in multiple directions rather than a single linear path. This allows the optical path length to be sufficiently long for high-quality projection while the enclosure depth remains minimal, as the light travels through a compact, multi-directional path within the enclosure
3Measurement precision
If conventional projection optics are used to achieve high resolution and contrast, then image quality is maintained, but the system requires larger enclosure dimensions
Solution Approach 1:
The patent modifies the optical parameters by implementing a telecentric lens arrangement with specific focal length ratios and aperture configurations. These parameter changes enable the system to maintain high image resolution and contrast while reducing the physical size of the optical components and their required spacing, thereby shrinking the overall enclosure volume
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 achieves a compact enclosure with minimal 'chin' and 'depth' dimensions while maintaining high resolution, contrast, and stability, comparable to LCD and plasma displays, and is scalable for larger screen sizes with improved thermal stability.
Implementation Method 1
incorporating a laser-based light source
Implementation Method 2
folding mirrors is used to minimize the 'chin' and 'depth' dimensions
Implementation Method 3
aspheric lenses, and folding mirrors is used to minimize the 'chin' and 'depth' dimensions
Data Source
AI summary
A micro-mirror based projection display system in an enclosure with minimum chin and depth measurements is disclosed. A light source, such as a solid state laser light source, generates light of multiple primary colors that is modulated by a digital micro-mirror device. The projection optics of the system include a telecentric rear group of glass lenses with spherical surfaces, followed by a pair of aspheric lenses formed of plastic. A folding mirror, such as a single-piece or multi-piece angular mirror, is disposed between the aspheric lenses, to reduce the depth of the enclosure, and an aspheric mirror projects the image onto a TIR Fresnel projection screen. The aspheric lenses are magnifying to reduce the magnification required of the aspheric mirror, and the aspheric lenses and mirror are clipped to reduce enclosure volume. A folding mirror may be used after the aspheric mirror to further reduce the depth of the enclosure.