Electrochromic Light Sensors and Controls

We all are fascinated by light and its many changes in a 24-hour period of time. We’ve learned the scientific reasons for sunlight, as well as the benefits to human existence. We’ve also learned to appreciate light and its gradual change to darkness as part of daily living so that our lifestyles adapt accordingly.

It should surprise no one that given all we have learned about light and darkness that it would be embraced as a highly technology that provides a wealth of benefits. Originally, controlling light and darkness and the changes was largely the domain of those in the photographic industry. Soon the optical benefits of this new technology led to innovations in eyewear and protective glass lenses.

What is Electrochromic Technology?

In laymen’s terms, electrochromic technology is the control of daylight and darkness, However, there is more to this innovative switchable smart glass technology that can be transmissive, reflective and deflective. It can transmit light through material, reflect certain light spectrum changes in daylight and also deflect harmful UV rays of the sun.

There are several major components of electrochromic smart glass technology. These include:

  • Lithium ions
  • Voltage
  • EC smart tint
  • Polymer material or pdlc film
  • Liquid crystal

Imagine a cross sectional view of tempered glass with several layers between two outer panes. The electrochromic layer is activated to detect changes by a layer tungsten oxide and nickel oxide. These layers are set inside two transparent electrical conductors and also a electrolyte that attracts voltage. When low voltage is applied, this activates the electrolytic layer which causes the material to react transmissively, reflectively or deflectively depending on the desired result.

Examples of ECDs

Ideally a visible light sensor or control is needed to detect certain changes in many types of testing procedures in laboratories and testing and monitoring for environmental purposes. These sensors are based on electrochromic glass and solar heat gain technology.

Typically, an electrochromic device (ECD) consists of four parts. These include:

  • Substrate
  • A conductive electrode
  • Electrochromic material
  • Electrolyte

Most electrochromic devices (ECD) are easily identifiable. An example of a transmissive ECD is a taser as used in law enforcement as a method of restraint. The example of a reflective ECD is a fishing lure and fly reel that attract fish due to the reflection of sunlight. An example of a deflective ECD is a fan or glass pane that deflects light to prevent overheating.

ECD Light Sensors and Controls

Perhaps one of the most important uses of ECDs is in medical and dental diagnostics. These ECDs are used for early detection and prevention of illness and dental problems. Many ECDS are also used as monitoring devices by architects, civil, specifying and environmental engineers, as well as building inspectors and construction contractors.

ECD Controls

ECD probes as a particle device provide an accurate evaluation assessment of the quantity of microns or electrons contained within a specific mass. ECD probes are found in R&D laboratories. They are also used by field service technicians for monitoring purposes to detect contaminants in soil and water.

For example, an outflow of contaminated or hazardous material such as paint particles or indium tin oxide into groundwater requires monitoring with an ECD probe to discover the actual depths of penetration of contamination and levels of toxicity. This type of monitoring in the U.S. is mandated by the U.S.EPA and state departments of environmental protection, as well as local municipalities.

Another example of an ECD device is one that controls the amount of daylight to conserve energy and protect from excessive solar radiation and solar heat gain. Harmful solar radiation has increased as a result of loss of the safety shield known as the ozone layer. The ozone layer aa a protective shield for humans is an area of the earth’s stratosphere. It absorbs a significant amount of the sun’s ultraviolet radiation. As such, the ozone layer also contains a high concentration of ozone as it relates to other parts of the atmosphere. Although, the ozone layer remains small in comparison to other gases found in the earth’s stratosphere.

The Need for Electrochromic Windows and Doors

In order to provide optimal protection from solar radiation, buildings and residential contractors are realizing the benefits of intelligent glass control for windows and doors. Glass manufacturers have addressed the need for intelligent glass control by creating smart glass used for the manufacture of smart windows and switchable privacy glass that replaces curtains and window blinds.

Switchable privacy glass, as its name implies, uses low-voltage electrical currents to arrange liquid crystal molecules into a random pattern. This makes the glass transparent when it is turned on. When the glass is turned off, these liquid crystal molecules changes to a random pattern. In effect, this action diffuses sunlight and causes glass to become opaque. These types of windows are also controlled by state-of-the-art dimmer switches. Switchable privacy glass is ideal for offices, retail stores and hospitals. This allows human input into the control of the volume of sunlight.

Smart Windows Do More

Today’s homes and building owners demand more from window installers than ever before. The most desirable modern windows are those that are stylish and offer optimal energy efficiency. A smart window does more than protect from excessive sunlight. A smart window intelligently regulates transmission of solar heat as emanated by solar radiation. This functionality reduces the cost of energy and creates a virtual temperature controlled interior for homes and buildings. One interesting feature of a smart window is that as the glass window darkens, they become similar to solar cells.

Innovations in Smart Windows

Researchers at the US Department of Energy’s National Renewable Energy Laboratory (NREL) combined two technologies, solar and electrochromic, into a single window. Their new study created a new technology The “thermochromic photovoltaic” tech, switches glazing film colors when heated by sunlight. This blocks sharp glare and reduces the need for cooling. In this process, this technology harvests energy from heated sunlight similar to the way solar cells store sunlight to heat and cool homes and buildings.


The growth of the use of intelligent glass is attributable to the focus on green energy initiatives and architects who pursue green designs for buildings and homes. The key factors driving the smart glass market grows as switchable smart glass and smart film growth demands surge for these products. Another factor is the demand by the transportation industry for safety in car windows and also in the construction industries where green building implementation of a smart glass window augments the public’s desire for designs that are cost-effective and energy efficient. The basic premise of this technology is to rethink our outmoded ideas and replaced them with today’s most healthy, convenient, safe and comfortable environment.

Looking to learn more about electrochromic products? Check out these other awesome guides:

Electrochromic Light Sensors and Controls

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