Due to the ultra-low profile and footprint, reflective encoder chips and discs have become very popular for miniaturized robotics such as household vacuum robots, pan and tilt applications for cameras, portable medical equipment, LIDAR, and other applications using miniature motors like drones and actuators.
Photo Solutions Reflective Encoder Chips and Discs
Miniature IC optical encoder chips with the LED and optical sensor are integrated into small-footprint QFN packages that allow for reduced costs and applications requiring miniaturization. Since all the optics and circuitry are on one side of the disc, reflective mode encoders have a very small profile compared to transmissive encoders, which allows for integration into motors, gears, and space-restricted applications. Let’s explore some key differences between reflective encoder discs, starting with the Encoder LED wavelength.
Encoder LED Wavelength
The wavelength of reflective encoder LEDs ranges from 460nm for iC-Haus Encoder Blue encoder series to 870 nm for Broadcom AEDR encoder chips. Depending on the reflective disc material, the percentage of reflectance varies.
Reflective Disc Technology Materials
At Photo Solutions, we engineer three types of reflective discs: reflective glass discs, mylar, and reflective aluminum. Here’s a bit more information about each:
Reflective Mode Glass Discs
Photo Solutions’ high reflective chrome (HRC) coating is available with > 60 percent reflectivity from 400-1000 nm. These high reflective/transparent patterns or high reflective patterns with ultra-low reflective chrome deposited on the backside of the disc help to eliminate unwanted reflections from other components. This helps minimize any unwanted reflections that may be present at under 5 percent in the 550-720 nm range.
Chrome on glass also has the most specular reflectance due to the extreme fatness and front surface coating. This is particularly desirable in encoder chips such as the iC Haus Encoder Blue series, which has a lensless LED. Gold coating for high-performance applications is available to image discs with transmissive and reflective patterns.
Reflective Mylar Encoder Discs
PET or Mylar composite discs are available with pressure-sensitive adhesive for easy mounting to any device. Photo Solutions provides these peel-and-stick discs and scales with protective liners and laser-cut registration features for easy installation. Available options include bonding to acrylic substrates to increase thickness and stiffness.
In addition to being the most economical choice, the aluminum reflective layer is 70% reflective from 550 nm and 80% at over 970 nm. The downside is that this is not a front surface reflector, as it is embedded in PET film. It is a great choice for Broadcom AEDR series encoder chips.
Reflective Aluminum Encoder Discs
Aluminum encoder discs are the best choice for high-temperature and tough environmental applications. The reflectivity of this material is 60 percent from 900 nm and 45 percent from 750 nm.
Order Your Reflective Disc Technology from Photo Solutions
Disc components are widely adopted for LED technology across various industries. For efficient lighting, data communication, electronic devices, or timekeeping, this technology has enabled LEDs to shine brighter, last longer, and contribute to a more sustainable future. Contact Photo Solutions to explore a quote for your custom materials and encoder disc technology needs.