Product description
By placing a layer of liquid crystal material between two glass sheets, transparency can be electronically controlled. The technology is used, for example, in welding helmets and window panes that can switch between clear view and privacy protection, known as "Privacy Glass." It can also be used to create a "revealing" effect in various projects.
A Liquid Crystal Light Valve (LCLV) is a device that utilizes the properties of liquid crystals to control the light level passing through an optical system. The principle is the same as in an LCD monitor, TV, or projector, but in this case, the entire surface is controlled instead of individual pixels.
In its normal state, the glass allows light to pass through, although slightly tinted. When a voltage of 3.3–5 VDC is applied, the glass switches to black and blocks the light.
The transition from transparent to dark occurs gradually. At around 1.0 VDC, the glass begins to darken, and at around 4.0 VDC it becomes practically opaque. 5 V is the highest recommended voltage. Note that the glass never blocks 100% of the light — the perceived blocking is approximately 95%.
Power consumption is almost negligible. Once the glass has been activated with a voltage, it will maintain its darkened state even if the power is removed. To restore transparency, a 0V signal or a discharge resistor between the two terminals is required to bleed off any residual voltage.
If the glass is to be kept dark for more than a few minutes, an AC square wave should be applied between the terminals to prevent DC bias that could damage the material.
Note that the glass sheet is very thin and fragile — it cannot be bent or cut and must be handled with great care!
Specifications:
- LCD dimensions: 31 × 33 × 2 mm
- Glass dimensions: 36 × 36 mm
- Operating voltage: 3–5 V
- LCD type: TN transmission positive
- Weight: 5.2 g
