Projection Lens Focus Correction via Temperature Feedback
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Solution Overview
Problem
Conventional projection type image display apparatuses face challenges in accurately correcting focus deviations due to temperature changes and uneven lens production, as well as varying user environments, leading to unsuitable focus adjustments.
Innovation Solution
A system comprising a projection optical system with a movable focus lens, temperature sensors, memory for lens position data, and a focus lens control unit that adjusts the lens position based on temperature information, with a determination portion to recognize and correct any lens movement not performed by the control unit, allowing for adaptive focus correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a focus correction system measures temperature and corrects focus based on temperature information, then focus deviation due to temperature change is reduced, but the correction may be inaccurate if focus adjustment is performed during use or if production/environmental variations exist
Solution Approach 1:
The patent implements feedback by detecting actual focus lens position movements and using this information to correct lens position data stored in memory. The system continuously monitors focus lens position through detection means, compares detected positions with expected positions from stored data, and automatically corrects discrepancies by updating the stored lens position data. This feedback mechanism enables the system to adapt to user operations and environmental variations, improving both reliability and adaptability of focus correction.
2Ease of operation
If focus correction is started at power supply turn-on, then correction timing is simplified, but focus may be deviated at start time or correction performed under incorrect conditions
Solution Approach 1:
The patent applies preliminary action by pre-storing lens position data in memory that represents the relationship between temperature and optimal focus lens position. This data is prepared in advance based on predetermined conditions and stored for later use. When the system operates, it retrieves and applies this pre-prepared data after detecting actual position movements, avoiding the need to perform complex calculations or adjustments at startup while ensuring accurate focus correction from the beginning.
3Reliability
If conventional focus correction based on temperature is used, then temperature-induced focus deviation is addressed, but production unevenness and environmental variations cause incorrect corrections
Solution Approach 1:
The patent implements self-service by enabling the system to automatically detect focus lens position movements and autonomously correct its own stored lens position data without external intervention. The detection means monitors actual positions, the control unit compares detected positions with stored data, and the system automatically updates memory with corrected data. This self-correcting capability allows the system to compensate for production unevenness and environmental variations, maintaining reliable focus correction despite manufacturing tolerances.
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 system effectively corrects time-dependent focus changes and adapts to user operations and environmental conditions, ensuring precise focus adjustments even with uneven lens production and varying use environments.
Implementation Method 1
the lens hold frame thermally expands, so that the position of the projection lens deviates
Data Source
AI summary
A projection type image display apparatus (1) comprises a focus correction system (30). The system includes a temperature detection mechanism (16) for measuring temperature in the vicinity of a projection lens group (13), a correction amount calculation unit (18) for calculating a correction amount for correcting the focus shift caused by a temperature change, and a driving signal generation unit (19) for generating, based on the correction amount, a driving signal for driving a focus adjustment mechanism (15). If the user performs a focus adjustment using a focus operation input unit (23), a focus operation determination unit (21) determines that a focus adjustment has occurred independently of the focus correction system and changes a correction condition stored in a memory (20).