The assembly and testing of long-wave infrared (LWIR) cameras pose several challenges that demand the utilization of a mature active alignment (AA) machine and a suitable optical target module for precise camera alignment and assembly. This presentation will review the technical approach to addressing these challenges, highlighting the development of an advanced AA machine and a specialized optical target module equipped with LWIR target projectors. These components offer significant technical differentiations through unique design and functionality, with specific design details remaining proprietary.
A mature camera active alignment machine should possess several critical attributes such as high precision, accuracy, advanced automation and control, high-speed processing, and versatility to handle various camera types. Additionally, robust software integration, environmental stability, user-friendly operation, repeatability, and built-in diagnostic tools enhance its functionality. Scalability, cost-effectiveness, and compliance with industry standards are also essential aspects.
Innovations in optical target module designs are vital to achieving scalable and cost-effective production of superior-performance LWIR sensors. Unlike semi-automated solutions with unverified performance, these innovations ensure high-throughput and high-yield thermal camera alignment. These measurable benefits include improved yield, reduced cycle time, lower implementation time, minimized scrap, and optimized capital and operational expenditures. These advancements collectively contribute to a reduced cost per camera, thereby setting a new standard in the industry for LWIR camera assembly and testing efficiency.
Introduction
Long-wave infrared (LWIR) cameras are critical components in various applications, including security, surveillance, and industrial inspection. Precision assembly and alignment of these cameras are paramount for optimal performance. However, traditional assembly often struggles to meet the required levels of accuracy and throughput. This presentation will discuss the advancements in LWIR camera assembly through the utilization of a mature active alignment (AA) machine, highlighting the technical differentiators and benefits of our approach.
Challenges in LWIR Camera Assembly and Testing
The assembly and testing of LWIR cameras require meticulous alignment of optical components to ensure optimal performance. Key challenges include:
- Precision Alignment: Achieving single-micron level precision in aligning optical elements.
- High Throughput: Balancing the need for high-speed processing with maintaining alignment accuracy.
- Environmental Control: Ensuring stable performance under varying environmental conditions.
- Automation: Minimizing manual intervention to reduce human error and increase efficiency.
Application in the Automotive Industry
In the automotive industry, the New Car Assessment Program (NCAP) is increasingly pushing car manufacturers to improve the performance of Advanced Driver Assistance Systems (ADAS), especially Pedestrian Autonomous Emergency Braking (PAEB) systems. Traditional ADAS sensors, such as visible light cameras and LiDAR, are generally effective in meeting the functional requirements for pedestrian and obstacle detection under normal environmental conditions. These technologies, however, show limited performance in adverse conditions, such as night, fog, rain, and snow. To address this challenge, the automotive industry has recently considered deploying thermal cameras in PAEB systems.
Thermal cameras are sensitive to the infrared spectrum from 7 to 14 microns. Using infrared (IR) radiation, thermal cameras do not need any light source and thus can provide expected performance in most weather conditions and at any time. In addition, the form factor and optical performance of thermal cameras make the technology a logical drop-in for ADAS. Moreover, thermal cameras are no longer a luxury option but an affordable and viable solution for PAEB systems. It is foreseeable that the need for thermal cameras will ramp up quickly and substantially in the short term. Building high-quality thermal cameras with high throughput and high yield will pose a challenge for Tier-1 automotive module suppliers.
Technical Differentiators
Our approach to LWIR camera assembly leverages several technical differentiators that enhance the overall performance and efficiency of the process:
- Advanced AA Machine: The CMAT (Camera Assembly and Test) system, integrated with proprietary software, offers unparalleled precision and control in the alignment process.
- Specialized Optical Target Module: Equipped with our unique LWIR target projectors, each module is designed for a thermal camera for its specific alignment requirements, ensuring precise alignment and enhancing the overall assembly process.
- Proprietary Design: Our LWIR target projectors, though proprietary, have outstanding advantages of compact size, modular design, and automated tooling validation, which significantly lowers the space requirement of optical target module designs while providing satisfactory performance and reliability for the thermal camera assembly process.
Key Attributes of a Mature AA Machine
The CMAT system, as a mature AA machine, incorporates the following key attributes:
- High Precision and Accuracy: Ensures sub-micron level precision in aligning optical components.
- Advanced Automation and Control: Minimizes manual intervention and provides sophisticated control systems for precise adjustments.
- High-Speed Processing: Handles large volumes efficiently, reducing cycle time per unit and increasing overall throughput.
- Versatility: Accommodates various camera types and configurations, including different sensor sizes and lens types.
- Robust Software Integration: Provides real-time monitoring, feedback, and adaptive control to fine-tune alignment parameters dynamically.
- Environmental Stability: Maintains consistent performance under various environmental conditions.
- Ease of Use: Features a user-friendly interface and operational simplicity for easy setup, operation, and maintenance.
- Repeatability and Consistency: Delivers consistent alignment results across multiple units, ensuring uniformity and high-quality output.
- Diagnostic and Monitoring Tools: Includes built-in diagnostic tools for troubleshooting and monitoring system performance.
- Scalability: Offers flexibility to scale operations as production demands increase.
- Cost-Effectiveness: Balances initial capital expenditure with long-term operational costs, ensuring a favorable return on investment.
- Compliance and Standards: Adheres to industry standards and regulations, ensuring compatibility and quality assurance.
Implementation and Results
ASMPT is widely recognized as the de facto leader for automotive camera active alignment solutions. Anticipating the potential market need for thermal camera active alignment, we have developed multiple configurations of long-wave infrared (LWIR) target projectors that facilitate the alignment of various thermal cameras in the mass production environment:
- Elimination of Active Projector Reticle Cooling: Designed to eliminate the need for active projector reticle cooling. This design modification not only ensures the compact size and low cost of the LWIR target projectors but also maintains the measurement accuracy of the Modulation Transfer Function (MTF) in the thermal camera device with the use of unique reticle designs.
- Modular Design: Incorporated with a modular design that allows critical components, such as the objective lens and the reticle, to be configured according to the specific requirements of each thermal camera design. This flexibility ensures optimal alignment performance.
- Built-in EEPROM: Equipped with a built-in EEPROM that stores critical device information, including the projector’s serial number, enabling automatic tooling validation.
- Seamless Integration: Seamlessly integrated into the ASMPT CMAT system, which is already in use by our customers. LWIR target projectors and ASMPT AEi’s visible-NIR target projectors use the same controller, mounting features, and toolless projector changeover capability.
A recently completed project with a top US thermal imaging supplier validates our CMAT system, combined with LWIR target projectors. The collaboration resulted in actively aligned thermal cameras with a yield rate of ≥ 95% and a throughput of ≥180 units per hour (UPH). The advantages of CMATs, including compact floor space requirements, high reliability, high throughput, and excellent yield, have been replicated in the mass production of thermal cameras.
Conclusion
The technical advancements in LWIR camera assembly and testing to be presented offer a superior solution to the challenges faced in the industry. The mature AA machine, combined with the specialized optical target module, ensures high precision, efficiency, and reliability in LWIR camera manufacturing. These innovations result in measurable improvements in yield, cycle time, implementation time, scrap reduction, and cost efficiency. With the rising demand for thermal cameras, particularly in automotive ADAS applications, the ASMPT solution is well-positioned to effectively meet the industry’s growing needs.
Biography
Dr. Lu Ren. in Mechanical Engineering from the University of Toronto, is the lead of the systems engineering team at ASMPT. With specialization in ADAS camera alignment and testing, Dr. Ren has actively led critical customer projects and spearheaded the design and development of optical target module designs for the past decade. His expertise extends to visible-NIR and long-wave infrared (LWIR)target projectors. Notably, Dr. Ren holds a patent for his exceptional optical target module design. Email: [email protected]
