Projector Focus Controller Thermal Expansion Correction
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Solution Overview
Problem
Conventional projectors are unable to correct focus deviation immediately after turning on the light source due to thermal deformation of lenses and lens barrel components, leading to image blurs and difficulty in maintaining sharp images.
Innovation Solution
A projection display apparatus and method that classify components of the projection optical system into groups based on their response times to light intensity and temperature changes, continuously calculating and correcting focus deviations in real-time using temperature and light intensity data from sensors, and adjusting focusing accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional focus correction function using a correction table is used, then focus deviation during normal operation can be corrected, but focus deviation immediately after turning on the light source cannot be corrected
Solution Approach 1:
The projection lens is divided into multiple component groups (first through fourth lens groups) with different thermal characteristics. Each group is assigned a different correction coefficient based on its specific thermal expansion properties, allowing differentiated focus correction for each component group rather than applying a single correction value to the entire lens system.
Solution Approach 2:
The invention changes the correction parameters dynamically based on temperature conditions. Different correction coefficients are applied depending on the temperature range and the specific component group being corrected. This allows the system to adapt the focus correction amount to the actual thermal state of each lens group, enabling effective correction even during rapid temperature changes after light source activation.
2Object-affected harmful factors
If the projection lens and peripheral members are subjected to thermal expansion, then the focus state is disturbed causing image blurs, but the conventional correction method cannot respond quickly enough to immediate post-power-on conditions
Solution Approach 1:
The invention calculates and applies focus correction amounts for each component group based on their respective correction coefficients before the focus deviation becomes significant. By having pre-established correction coefficients for each lens group and applying them proactively based on temperature changes, the system can compensate for thermal expansion effects before they cause noticeable focus degradation.
Solution Approach 2:
The system continuously monitors temperature changes and applies real-time focus correction based on the detected temperature and the predetermined correction coefficients for each component group. This feedback mechanism allows the system to dynamically adjust the focus position in response to thermal expansion, maintaining sharp images even during rapid temperature changes after power-on.
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 approach allows for immediate correction of focus deviations upon light source activation and deactivation, ensuring sharp images are maintained by classifying and addressing the unique focus deviation characteristics of different component groups within the projection optical system.
Implementation Method 1
the rise of the internal temperature of the projector after turning on the light source device causes thermal expansion of the projection lens and its peripheral members, so that a focus deviation is generated
Data Source
AI summary
A projection display apparatus for projecting and displaying image light onto a projection plane includes an image light generator that generates the image light, a projection optical system including a projection lens that projects the image light onto the projection plane, a focus controller that controls focusing of the projection lens, and a temperature sensor that detects a temperature of the projection display apparatus. The focus controller operates to, calculate a plurality of focus deviation amounts which correspond respectively to a plurality of component groups based on first information obtained from the image light generator and second information obtained from the temperature sensor, the plurality of component groups being classified depending on kinds of components constructing the projection optical system, calculate a focus correction amount according to the plurality of focus deviation amounts calculated, and control the focusing based on the focus correction amount calculated.