Case Study: Infrared Lens Design

 

Design for Manufacturing (DFM) Case Study: Infrared Lens Design for Scientific Equipment

At Avantier we offer Design for Manufacturing (DFM services), optimizing product design with our extensive knowledge of manufacturing constraints, costs, and methods.

Measuring the relative concentrations of carbon monoxide, products of combustion and unburned hydrocarbons is the basis of flare monitoring and is typically accomplished with infrared spectral imaging. For real time continuous monitoring, a multispectral infrared imager can be used. 

We were approached by a scientific equipment supplier for DFM help on a particular infrared lens (50 mm f/1) that is used in their infrared imager. The lens was designed to offer the high image quality and low distortion needed for scientific research, but though it performed as desired, there were two major manufacturing problems that made it expensive to produce. The first issue was expensive aspheric lens elements. The second was the inclusion of GaAs to improve the modulation transfer function (MTF) and to correct chromatic aberration. GaAs is a highly toxic material, and incorporating it in the design complicates the manufacturing process and increases the cost. 

Taking into account both lens performance and our client’s manufacturing budget, Avantier redesigned the infrared lens with DFM principles. Our final design included no aspheric lens elements and no hazardous material, but we met all requirements for distortion, MTF, and image height offset at the working spectral lens. Using a combination of 5 spherical lens elements and 1 filter, our 50 mm f/1 lens was able to reduce the lens cost by about 60%.

In the below image the configuration of the 50 mm f/1 lens is shown. For a wavelength range of approximately 3 to 5 µm the MTF was 0.7, well within our client’s requirements.

The next image below shows the modulation transfer function (MTF) plots for the redesigned lens.

This last image below shows the lens distortion plot. The maximum field was 6.700 degrees, and the maximum f-tan distortion 0.6526%.

Whatever your need might be, our engineers are ready to put their design for manufacturing experience to work for you. Call us to schedule a free initial consultation or discuss manufacturing possibilities.