Optical Axis Deviation for Compact Image Projection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image projection apparatuses have a lengthy 'screen-underlying portion' due to the arrangement of the lighting optical system, which hinders compact design and aesthetic appeal, as the light source reflector is often positioned at or below the optical axis of the projection light, increasing the overall height and bulk of the device.
Innovation Solution
The optical system is designed such that the lighting optical system's optical axis is positioned in a deviated area away from the luminous flux of the projection light, allowing the lighting system to be compacted and arranged horizontally, reducing the screen-underlying portion's length and eliminating the need for a bulge, thereby enabling a more compact image projection apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lighting optical system is arranged at or below the optical axis of projection light, then the light source reflector can be effectively positioned, but the screen-underlying portion length increases
Solution Approach 1:
The patent applies dimensionality change by deviating the lighting optical system's optical axis from the projection light's optical axis in the vertical direction. Specifically, the lighting optical axis is positioned at a first angle relative to the horizontal plane, while the projection light optical axis is at a second angle, creating angular separation. This allows the lighting system to be arranged in a different spatial dimension without interfering with projection light, thereby reducing the screen-underlying portion length while maintaining effective light source reflector positioning.
2Length of stationary object
If the light source is raised and the optical axis is greatly inclined, then the screen-underlying portion length is reduced, but the light source life is shortened
Solution Approach 1:
The patent applies parameter changes by optimizing the inclination angle of the lighting optical axis. Rather than using a great inclination angle that would shorten light source life, the patent positions the lighting optical axis at a first angle to the horizontal plane that is sufficient to reduce the screen-underlying portion length but not excessive enough to harm light source longevity. This balanced angular parameter achieves both compactness and durability.
3Device complexity
If the lighting optical system is arranged below the projection optical system, then the structure is simplified, but the screen-continuing portion area increases
Solution Approach 1:
The patent resolves this contradiction by using angular separation in the vertical dimension. The lighting optical system's optical axis is deviated from the projection light's optical axis by positioning them at different angles to the horizontal plane. This allows both optical systems to coexist in the same horizontal footprint without one being positioned directly below the other, thereby maintaining structural simplicity while reducing the screen-continuing portion area.
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 allows for a significant reduction in the screen-underlying portion's length, enhancing the compactness and aesthetic appeal of the image projection apparatus while extending the life of the light source by avoiding excessive inclination, which typically shortens its lifespan.
Implementation Method 1
a lighting optical system leading light from a light source for lighting the reflection type display element or the transmission type display element
Implementation Method 2
a projecting optical system for projecting light reflected from the reflection type display element and containing image information
Data Source
AI summary
The invention provides an optical system for image projection, wherein when used in an image projection apparatus, a screen-continuing portion (e.g., screen-underlying portion) of the apparatus can be reduced to a small size, or can be removed, and thereby the apparatus can be so compacted, and provides an image projection apparatus mounting such optical system. An optical system 10 for image projection including a lighting optical system 1 leading light from a light source 11 for lighting a display element 4 (or 4′), and a projecting optical system 3 for projecting projection light containing image information from the display element 4 (or 4′). The lighting optical system 1 is arranged such that a straight optical axis α from the light source 11 in the lighting optical system 1 is positioned in an area deviated from a luminous flux β of the projection light incident into the projecting optical system 3 toward an area where the projection light γ from the projecting optical system 3 passes. The image projection apparatus A (or B or C) mounting such optical system 10.