Camera Module UV Curing Feedback Control
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Solution Overview
Problem
In volume production of automotive camera modules, UV curable glue curing processes often result in inconsistent results and increased cycle time due to unpredictable UV exposure, with existing UV light sensors obstructing the curing process and failing to monitor the entire area effectively.
Innovation Solution
The method involves using the camera module's image sensor, which is sensitive to UV radiation, to provide feedback for controlling UV radiation sources during the curing process, ensuring consistent curing by measuring the glue's opaqueness and optimizing cycle time without obstructing the optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a UV light sensor is used to monitor the UV exposure, then the UV exposure can be monitored, but the sensor obstructs some of the light intended for the curing process and only measures light locally
Solution Approach 1:
The image sensor in the camera module serves dual purposes: it captures images for the camera's primary function and simultaneously monitors UV exposure during curing by detecting changes in light transmission through the glue. This self-service approach eliminates the need for a separate UV sensor that would obstruct the curing light.
Solution Approach 2:
The image sensor is utilized for multiple functions: its primary imaging function and an additional function of UV exposure monitoring during glue curing. By making the sensor multi-functional, the system avoids adding separate monitoring components that would interfere with the curing process.
2Reliability
If UV exposure time is extended to ensure complete curing, then curing completeness improves, but cycle time increases
Solution Approach 1:
The system implements real-time feedback control by continuously monitoring UV exposure through the image sensor and adjusting the curing process accordingly. The UV exposure monitor provides feedback signals that trigger automatic shutdown when curing is complete, preventing both under-curing and excessive exposure time.
Solution Approach 2:
The curing process transitions from a static, predetermined time-based approach to a dynamic, condition-based approach. The system continuously adapts the curing duration based on real-time monitoring of glue transparency changes, allowing optimal curing time to be determined automatically for each situation.
3Ease of manufacture
If constant UV exposure level is applied for a predetermined time, then the process is simple, but curing results vary with larger spread and lower yield
Solution Approach 1:
The system replaces simple open-loop control with closed-loop feedback control. The UV exposure monitor continuously measures actual curing progress and provides feedback to the control unit, which adjusts UV exposure parameters in real-time to maintain consistent curing results across all production units.
Solution Approach 2:
The system replaces mechanical/timed control mechanisms with an optical sensing and electronic control system. Instead of relying on predetermined timers, the curing process is controlled by optical feedback from the image sensor that detects actual glue curing state, substituting electronic control for mechanical timing.
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 precise control of UV exposure, reducing cycle time and increasing throughput by ensuring consistent curing results and high yield in key performance parameters, while maintaining the optical path integrity.
Implementation Method 1
curing the glue using at least one UV radiation source
Implementation Method 2
the at least one UV radiation source is controlled using feedback provided by the image sensor of the camera module... the image sensor of the camera module which, surprisingly, is sensitive to UV radiation
Data Source
Figure 1
Figure 2~5
Figure 3~4
AI summary
A method of assembling a camera module (12) for a motor vehicle comprises providing a lens unit (86) forming a lens objective (20), providing a back unit (90) carrying an image sensor (24), applying UV curable glue (80) to the lens unit (86) and/or to the back unit (90), positioning the lens unit (86) and the back unit (90) relative to each other, and curing the glue (80) using at least one UV radiation source (82) while holding the lens unit (86) and the back unit (90) in a relative position and orientation in order to form a glue joint (80) between the lens unit (86) and the back unit (90). During glue curing, the at least one UV radiation source (82) is controlled using feedback provided by the image sensor of (24) of the camera module (12).