Ultra-short Throw Projector Prism Light Path Folding
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Solution Overview
Problem
Ultra-short throw projectors have a large size due to multiple lenses arranged linearly, making them bulky and costly, which limits their portability and integration with other devices like virtual reality displays and scanners.
Innovation Solution
Incorporating a prism in the lens system to change the light path, processing the prism's surfaces as aspheric or freeform surfaces to reduce the number of lenses and omit aspheric processing, thereby miniaturizing the projector and reducing its weight and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple lenses are arranged linearly in the lens system, then the projector can achieve ultra-short throw projection, but the device size increases significantly
Solution Approach 1:
The patent applies dimensional change by folding the optical path using reflection mirrors. Instead of arranging lenses in a straight linear sequence (one dimension), the optical path is bent and folded back on itself, effectively utilizing three-dimensional space. This allows the optical path length to be extended while keeping the physical footprint of the projector compact, resolving the contradiction between achieving ultra-short throw projection and maintaining a compact device size.
2Measurement precision
If multiple lenses with aspheric processing are used, then image quality is improved, but the device weight and manufacturing cost increase
Solution Approach 1:
The patent merges the aspheric optical function into a single reflection mirror rather than requiring multiple separate aspheric lenses. By integrating the light-bending and focusing functions into one mirror component with a specially designed reflective surface, the system achieves the necessary image quality while reducing the total number of components, thereby decreasing weight and simplifying manufacturing.
Solution Approach 2:
The patent substitutes refractive optical elements (lenses) with a reflective optical element (mirror). This replacement eliminates the need for multiple aspheric lenses and their associated mounting structures, reducing the overall weight of the projector while maintaining the required optical performance through carefully designed reflective surfaces.
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 significantly reduces the projector's size by up to 45% in one direction, enhancing portability and enabling easier integration with other devices while maintaining image quality and cost-effectiveness.
Implementation Method 1
a light path changing prism configured to change a light path in the vertical direction or other directions
Implementation Method 2
at least one of an incident surface and a refracting surface being an aspherical surface or a freeform surface
Implementation Method 3
a reflection mirror configured to reflect and magnify the second intermediate image and form an image on a screen
Data Source
AI summary
An ultra-short throw projector device includes a lens system. The lens system includes a first lens group configured to form a first intermediate image from an incident display image; a second lens group configured to form a second intermediate image from the first intermediate image; an aperture configured to be disposed on a point where the first intermediate image is formed between the first lens group and the second lens group; a reflection mirror configured to reflect and magnify the second intermediate image and form an image on a screen; and a light path changing prism configured to change a light path in the vertical direction or other directions, the prism being disposed at a point on the light path of the lens system, at least one of an incident surface and a refracting surface being an aspherical surface or a freeform surface.