Dichroic Mirror Incident Angle Optimization for Compact Projector Design
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Solution Overview
Problem
Conventional projection-type image display apparatuses, especially those mounted on ceilings, face challenges in miniaturization, image quality deterioration, and aesthetic considerations due to their size and structural requirements.
Innovation Solution
A projection-type image display apparatus is designed with a light source unit that includes semiconductor lasers exciting phosphor, a dichroic mirror arranged at an incident angle of 50° to 60° to optimize light usage and miniaturization, combined with a light-guide optical system and projection optical system for efficient image generation and projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the projector is miniaturized to improve portability and aesthetic appeal, then the device size is reduced, but image quality deteriorates due to insufficient light utilization efficiency
Solution Approach 1:
The patent changes the incident angle of light onto the dichroic mirror from the conventional 45 degrees to 55 degrees or more. This dimensional parameter change optimizes the optical path efficiency and light utilization, enabling compact projector design without sacrificing image quality. The specific angle range (55-75 degrees) represents a precise dimensional adjustment that resolves the contradiction between miniaturization and light efficiency.
Solution Approach 2:
The patent modifies key optical parameters including the incident angle on the dichroic mirror (55-75 degrees), the focal length ratio (f2/f1 between 0.7-1.3), and the position of the condenser lens. These parameter changes collectively optimize the optical system for compact design while maintaining high light utilization efficiency and image quality.
2Loss of energy
If the incident angle of light on the dichroic mirror is increased to improve light utilization efficiency, then image quality improves, but the optical system becomes more complex and harder to miniaturize
Solution Approach 1:
The patent combines multiple optical functions into fewer elements. The dichroic mirror is positioned to perform both wavelength separation and light direction functions simultaneously at an incident angle of 55 degrees or more. The condenser lens and dichroic mirror are integrated in a compact arrangement that achieves both high light efficiency and compactness, reducing overall system complexity despite the non-conventional angle.
3Area of stationary object
If the projector is disposed on the ceiling for aesthetic appeal and space saving, then the occupied area is reduced, but dedicated holders and wiring works are required increasing installation complexity
Solution Approach 1:
The patent designs the projector with universal mounting capabilities that allow it to be installed on ceilings, walls, or placed on surfaces. The illumination device can function both as a projection device and as a general illumination source, eliminating the need for dedicated holders and specialized wiring. This multi-functionality resolves the contradiction between space saving and installation complexity.
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 enables miniaturization of the projector while maintaining high image quality by improving light utilization efficiency and wavelength separation, addressing the need for compactness and aesthetic appeal.
Implementation Method 1
a dichroic mirror that directs the light from the light source to the phosphor
Implementation Method 2
a dichroic mirror that directs the light from the light source to the phosphor
Implementation Method 3
phosphor that is excited by the light from the light source
Data Source
AI summary
A projection-type image display apparatus includes a light source unit that emits light, an image generating unit that generates image light according to an input video signal, a light-guide optical system that guides the light from the light source unit to the image generating unit, and a projection optical system that projects the image light generated by the image generating unit. The light source unit includes a light source that produces light, phosphor that is excited by the light from the light source, and a dichroic mirror that directs the light from the light source to the phosphor. The dichroic mirror is arranged with an incident angle of the light from the light source being 50° or more and 60° or less.