1-Step Cure Active Alignment Adhesive for High Resolution Automotive Camera Module Assembly

Consumer demand is propelling rapid growth of autonomous driving and advanced driver assistance systems. By 2030, McKinsey estimates 12 percent of vehicles will be equipped with Levels 3 and 4 Autonomous Driving capabilities, compared with only 1 percent in 2025.

High-resolution cameras play a key role in enabling the safe functionality of ADAS systems – responsible for ensuring quick, accurate detection of other vehicles, pedestrians, obstacles, traffic signs and more.

Active alignment adhesives help ensure cameras operate at peak performance across the automotive camera’s lifetime, while exposed to challenging conditions on the road, such as vibration, harshness and high temperatures.  This is achieved through precise positioning of the camera’s optical components to the image sensor while an adhesive is used to fix the components in place.

Key attributes of an effective active alignment adhesive include the ability to bond to a variety of substrates, quickly cure to high bond strength and exhibit low and consistent dimensional change.

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Camera Assembly Process

Traditional camera assembly processes take place across five steps, which includes a short UV cure of a few seconds, as well as a thermal cure and finish that can take as long as 30 to 100 minutes to complete before the adhesive reaches its final bond strength.

Now, automotive camera manufacturers have the option of using a 1-step cure active alignment adhesive, which eliminates the thermal cure step, while achieving full performance with just a few seconds of UV LED exposure.

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^{Top: Traditional camera module assembly process; Bottom: Camera module assembly process with 1-step cure adhesive}

Single-cure Active Alignment Adhesive Performance Results

LOCTITE ABLESTIK NCA 01UV 1-step cure adhesive meets all the requirements for high resolution cameras for automotive applications, showing high reliability, adhesion strength and low and consistent dimensional change - similar to dual-cure adhesives.

High cure depth is particularly important to ensure no contamination occurs that could degrade the quality of the camera image. LOCTITE ABLESTIK NCA 01UV 1-step adhesive demonstrates a remarkably high cure depth of 8 mm after 3 seconds. After just 1 second, cure depth is already as high as 7.2 mm.

Further testing revealed the material resulted in no contamination or outgassing even when left to harden in the dark at room temperature without exposure to any light (in accordance with NASA outgassing test). Results included the collection of 0.0% Volatile Condensable Material and a Recovered Mass Low of 0.42% - below the requirement of less than 1.00%.

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Commercial Benefits and Life Cycle Analysis

Elimination of the heat cure oven can result in significant benefits for automotive camera manufacturers.

Cost Savings

Assuming an average capital expenditure of approximately 88,000 USD (80,000 EUR) for a heat cure oven, with an annual maintenance cost of approximately 5,500 USD (5,000 EUR), LOCTITE ABLESTIK NCA 01UV would result in an annual cost savings of approximately 23,000 USD (21,000 EUR)¹ per year over 5 years for one oven (depreciation + maintenance cost). 

Sustainability

From a sustainability perspective, manufacturers can have a positive impact on sustainability by eliminating oven curing. The annual energy consumption of a medium range oven that is post-curing adhesive for 70 minutes at 80 degrees Celsius for a year¹ is equivalent to nearly 2.5 tons of CO2ⁱⁱ. To sequester this amount of carbon, about 42 tree seedlings would need to grow for 10 yearsⁱⁱⁱ.

Production Efficiency

LOCTITE ABLESTIK NCA 01UV enables optimization of the process time of the overall camera module assembly line. Since 99 percent of the cycle time can be attributed to oven curing, significant cycle time reduction can be achieved by eliminating the heat cure process step.

Interested in Learning More?

Download Henkel’s 1-step cure active alignment adhesive white paper here.

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^{[1] Assuming average capital expenditure of 80,000 Euros with an annual maintenance cost of 5,000 Euros over 5 years; a production rate of 240 cameras per hour, 84 kg of adhesive per year, and an oven of 112 meters long with a nominal power of 17 kWh using 1.6 kW to keep 80C, and a consumption of 63 kWh per kg of adhesive, leading to a yearly consumption of about 5,300 kWh}

ⁱⁱ https://ecoinvent.org/the-ecoinvent-database/

^iii. Greenhouse Gas Equivalencies Calculator | US EPA^: https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator#results