Liquid Crystal Light Valve / LCD Shutter

Liquid Crystal Light Valve / LCD Shutter

This product is a small liquid crystal light valve (also known as a controllable LCD shutter panel) created by applying power to a layer of liquid crystal material placed between two glass plates. This type of panel is commonly used in welding helmets, as it can protect the welder’s eyes from bright light during operation. In this case, however, it can provide a “reveal” effect, since the opacity of the LCD can be controlled.

A “Liquid Crystal Light Valve” (LCLV) is a device that uses the properties of liquid crystals to control the amount of light passing through an optical system (just like each individual pixel in LCD monitors, TV screens, and projectors).

This product features a small LCD capable of filtering what is visible through it. By default, it appears as a gray shade, because ambient light is not polarized, so it is not completely clear. There are two electrodes that allow you to apply voltage to change the opacity. The higher the voltage applied, the more light is blocked:

• • Starting at around 1V DC, the glass begins to darken.
  • At around 4V, the glass becomes opaque.
  • 5V is the maximum recommended voltage.
    Between these voltages, different levels of dimming can be achieved.

Note: This product cannot block 100% of the light, but it appears to block at least 95%. If you place a bright light behind the panel, some light may still pass through.

The current draw is almost negligible. Once voltage is applied, the glass will remain at that level of opacity even if the voltage is removed. Therefore, if you want to switch it on and off, you will need to drive it with a 0V signal to “open” it, or connect a discharge resistor between the two pins to remove residual voltage when not powered.

If you plan to keep it powered (opaque state) for more than a few minutes, you may want to use an AC square wave between the two pins to prevent damage caused by DC polarization. Refer to this file: Driving TN Shutters

Attention: This product is made of thin glass. It cannot be bent or cut and is very fragile. Handle with great care.

Technical Details – Liquid Crystal Light Valve

• • • • LCD size: 3.1 × 3.3 × 0.2 cm
      • Product dimensions: 3.6 × 3.6 × 0.18 cm / 1.4″ × 1.4″ × 0.1″
      • Driving voltage: 3-5V
      • LCD type: TN, transmissive, positive
      • Operating temperature: -10°C to 60°C
      • Product weight: 5.2 g / 0.2 oz

Adafruit name: Small Liquid Crystal Light Valve – Controllable Shutter Glass