Imager Shift Mechanism for Projection Display Alignment
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Solution Overview
Problem
In projection display devices, especially those of the oblique projection type, accurately positioning the imager relative to the projection optical system is crucial to prevent image blurring due to displacement, and existing methods require precise adjustment of the throw distance and imager placement, which can be cumbersome and prone to errors.
Innovation Solution
A projection display device with a shift mechanism that allows the imager to be displaced vertically relative to the optical axis, co-mounted with the projection optical system on a base member, reducing the number of intermediate components and enhancing precision in mounting, thus maintaining the correct positional relation between the imager and the optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the throw distance is changed to adjust projection size, then the projection size can be adjusted, but the position of the projected image is greatly displaced vertically on the projection plane
Solution Approach 1:
An imager shift mechanism is introduced as an intermediary device between the imager and the projection optical system. This mechanism allows independent adjustment of the imager position in the vertical direction, serving as a mediator to correct image position displacement caused by throw distance changes without affecting the projection size adjustment capability
Solution Approach 2:
The adjustment functions are segmented into two independent mechanisms: one for adjusting projection size (throw distance control) and another for adjusting image position (imager vertical shift). This segmentation allows each function to be optimized independently, resolving the conflict between size adaptability and position precision
2Ease of operation
If the imager is shifted in a state that the effective display surface is tilted with respect to the object plane, then the position of projected image can be adjusted, but the displacement between the end portion of the effective display surface and the object plane is increased causing image blur
Solution Approach 1:
The imager is pre-mounted on the shift mechanism with the effective display surface parallel to the object plane before use. This preliminary correct alignment ensures that when the imager is shifted vertically, the parallel relationship is maintained, preventing the tilt-induced displacement and image blur that would occur if the imager were already tilted
Solution Approach 2:
The shift mechanism acts as an intermediary platform that provides constrained vertical movement while maintaining the parallel alignment between the imager's effective display surface and the projection optical system's object plane. This intermediary structure enables position adjustment without compromising alignment precision
3Adaptability or versatility
If multiple components are mounted between the shift mechanism and the projection optical system, then the structure can be more flexible, but the positional error between the imager and the projection optical system increases causing image blur
Solution Approach 1:
The shift mechanism and projection optical system are merged into a single integrated assembly where the projection optical system is directly mounted on the same base member as the shift mechanism. This merging eliminates intermediate mounting interfaces, reducing cumulative positional errors while maintaining structural flexibility through the integrated design
Data Source
AI summary
A projection display device includes an imager which modulates light from a light source based on an image signal; a projection optical system which enlarges and projects the light modulated by the imager onto a projection plane; and a shift mechanism which displaces the imager in a direction intersecting with an optical axis of the projection optical system. The projection optical system and the shift mechanism are co-mounted on a base member.