Optical System Light Separation for Compact Projection
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Solution Overview
Problem
Existing image projection apparatuses face challenges in effectively eliminating unwanted light while maintaining a compact optical path, which affects the luminance and contrast of projected images.
Innovation Solution
The optical system incorporates a digital micromirror device (DMD) with a total internal reflection (TIR) prism unit, where light is directed through a boundary surface that transmits needed light and reflects unwanted light, preventing it from entering the projection unit by using a mechanically textured surface or light absorption band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield is inserted in the illumination optical path to block unwanted light, then unwanted light is blocked, but the optical path length increases and device complexity increases
Solution Approach 1:
The patent combines the illumination optical system and projection optical system into a single integrated optical path, eliminating the need for separate shields. The optical system uses a unified light path from the light source through the DMD to the projection lens, merging functions that were previously separated and requiring physical blocking elements.
Solution Approach 2:
The patent extracts and eliminates the shield component from the optical system by redesigning the optical path. Instead of adding a blocking element, the system uses the natural optical path design to prevent unwanted light from entering the projection unit, removing the harmful component entirely.
2Volume of moving object
If the optical system is compacted to reduce size, then device size decreases, but unwanted light may enter the projection unit affecting image quality
Solution Approach 1:
The patent uses a folded optical path design where light travels through multiple reflections and directional changes within a compact volume. The optical system employs mirrors and prisms to redirect light at various angles, effectively packing a long optical path into a small physical footprint while maintaining proper light separation.
Solution Approach 2:
The patent applies specific optical properties to different regions of the optical system. The illumination path and projection path are designed with different angular characteristics and spatial distributions, allowing compact arrangement while maintaining clear separation between useful light and unwanted light through localized optical design features.
3Object-affected harmful factors
If a shield is used to block unwanted light, then image contrast improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent removes the shield component entirely by designing an optical path that naturally prevents unwanted light from reaching the projection unit. The compact integrated design uses direct geometric relationships and angular separation to achieve light blocking without requiring additional manufactured parts.
Solution Approach 2:
The optical components in the patent serve multiple functions simultaneously. The same optical elements that direct and focus light also provide natural blocking of unwanted light paths, eliminating the need for dedicated shield components and simplifying manufacturing.
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 significantly increases the luminance difference between needed and unwanted light paths, enhancing image quality by keeping unwanted light away from the projection unit and allowing for a compact optical system design.
Implementation Method 1
an optical element (102) having a boundary surface (B) that transmits light rays (200) in a first direction and reflects light rays (250, 201) in a second direction
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An optical system (100) includes an optical element (102) configured to emit light emitted from a light source; and an optical modulation element (103) configured to receive the light emitted from the optical element (102) and emit first light rays in a first direction and second light rays in a second direction different from the first direction. The optical element (102) has an interface (B) that transmits one and reflects the other of: the first light rays to be directed to a projection target; and the second light rays and the light emitted from the light source.