Rotatable Projection Lens Shift Control for Vignetting Prevention
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Solution Overview
Problem
In projection apparatuses with rotatable lenses, existing technologies face challenges in accurately shifting and aligning projection images to prevent interference between the image and the apparatus body, especially when the lens posture or direction changes.
Innovation Solution
A projection apparatus with a rotatable lens system that includes a main body, an electro-optical element, a projection lens with multiple optical systems, posture information acquisition, detection units for rotation states, and a control unit to adjust the shift of the projection image based on acquired posture information and detection results to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the projection lens is rotated to change the projection direction, then the projection direction can be adjusted, but the projection image interferes with the apparatus main body (vignetting occurs)
Solution Approach 1:
The shift mechanism moves the projection lens in advance before rotation to pre-position the optical axis, preventing the image from interfering with the apparatus body during subsequent rotation operations
Solution Approach 2:
The system dynamically adjusts the lens position and orientation by combining shift mechanism movements with rotation operations, allowing real-time adaptation to different projection directions while maintaining proper image positioning
2Manufacturing precision
If the projection lens is moved relative to the housing by a shift mechanism to correct positional deviation, then the projection image position can be corrected, but the device complexity increases
Solution Approach 1:
The invention combines the shift mechanism with the rotation mechanism into an integrated system where both functions share common components and control logic, reducing overall device complexity while maintaining precise image positioning capability
Solution Approach 2:
The shift mechanism serves multiple functions: correcting positional deviation during rotation, preventing vignetting by pre-positioning the optical axis, and enabling accurate image alignment for different projection directions, thereby justifying the added complexity through multi-functionality
3Adaptability or versatility
If the projection lens is rotated to change projection direction, then projection flexibility is improved, but the projection image and apparatus main body interfere with each other
Solution Approach 1:
The shift mechanism performs preliminary positioning of the projection lens before rotation occurs, establishing the correct optical axis position in advance to prevent interference during the subsequent rotation and projection operations
Data Source
AI summary
A projection apparatus capable of appropriately performing shift control of a projection image when a posture or a projection direction of a projection lens is changed by rotating the projection lens is provided. A projection apparatus (1) includes a projection apparatus main body (2) that causes a DMD (22B) to emit a projection image; a projection lens (3) that projects the projection image emitted from the DMD (22B), the projection lens (3) including a second optical system and a third optical system, the second optical system being provided rotatably around a first rotation axis with respect to the projection apparatus main body (2), the third optical system being rotatable around a second rotation axis extending in a direction intersecting with the first rotation axis; a posture information acquisition unit that acquires posture information indicating a posture of the projection lens (3) with respect to the projection apparatus main body (2); a lens shift mechanism (80) that causes the projection lens (3) to move in a plane intersecting with an axial direction of the first rotation axis; and a control unit that controls the lens shift mechanism (80) based on the posture information acquired by the posture information acquisition unit to shift a projection image that is projected from the projection lens (3).