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---
description: "Cholesteric liquid-crystal drawing tablet"
created: 2024-05-19
---
[TOC]
## Prelude
I recently stumbled across drawing tablets seemingly works by the means of magic,
the search term is: `LCD writing tablet`
I have a thing for daylight viewable screens, so the allure was irresistible for me.
After one quick trip to the local hardware store, and subsequently the local hacker space,
i was able to examine the technology first hand, and for low monetary cost too, i might add.
## Properties
The properties are as follows:
- Daylight viewable
- Passive working principle (only requires power to clear the display)
- Pressure amount sensitivity (light pressure = thin line, hard pressure = thick line)
## Layers
The tablet consists of a sandwich of 3 layers:
- A dark background
- A layer of cholesteric liquid-crystals
- A piece of translucent plastic
## Functional principal
The means of function of this device, is merely a property of how the cholesteric liquid-crystal work:
[*"crystals flow at different rates, depending on the direction of pressure being applied"*](https://new.nsf.gov/news/how-liquid-crystal-displays-work-ewriter#:~:text=crystals%20flow%20at%20different%20rates%2C%20depending%20on%20the%20direction%20of%20pressure%20being%20applied)
[*"anisotropic flow causes the molecules to order themselves to reflect light in those places where a stylus touches the plastic sheet."*](https://new.nsf.gov/news/how-liquid-crystal-displays-work-ewriter#:~:text=anisotropic%20flow%20causes%20the%20molecules%20to%20order%20themselves%20to%20reflect%20light%20in%20those%20places%20where%20a%20stylus%20touches%20the%20plastic%20sheet.)
## Sources:
1. [How Liquid Crystal Displays Work in an eWriter - new.nsf.gov](https://new.nsf.gov/news/how-liquid-crystal-displays-work-ewriter#:~:text=The%20liquid%20crystals%20are%20surrounded,that%20they%20are%20less%20reflective.)
2. [Cholesteric liquid crystal - wikipedia.org](https://en.wikipedia.org/wiki/Cholesteric_liquid_crystal)
3. [Anisotropy - wikipedia.org](https://en.wikipedia.org/wiki/Anisotropy)
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