EIT week41-1 Electrochromic, Thermochromic, and Photochromic

Advanced Display Technologies: Electrochromic, Thermochromic, and Photochromic

Overview

• Course: Engineering Interaction Technologies
• Professor: Michael Wessely, Interactive Matter Lab

Electrochromic Displays

• Description: These displays do not emit light but change color through controlled chemical reactions.
  • two electrochromic layers used to store the ions
  • transparent conductor makes ion can be conveyed through each other
  • ITO can be the sheld to protect the whole structure
• Functionality: Color change is achieved by moving ions between two electrochromic layers, where one layer gains ions and becomes saturated, and the other loses ions and becomes transparent.
• Applications: Examples include Ynvisible for visual effects and VitaBoot, which blinks with the wearer’s heart rate.

Thermochromic Displays(Thermo = temperature, chromic = color)

• Definition: These displays change color in response to changes in temperature.
• Characteristics: Color transitions from one to another or from color to transparent are triggered by heat.
• Use Cases: Can be incorporated into textiles such as Duoskin or used in projects that combine heat elements with touch sensors for interactive experiences.

Photochromic Displays

• Principle: Color changes occur when the material is exposed to specific wavelengths of light.
• Details: These materials transition between color and transparent states under light exposure, typically UV light.
• Innovative Implementations: Includes UV LEDs for pattern creation, projectors for precise control, and multi-color configurations using different photochromic inks.
• Limitation: One color only, but can be mixed with different colors.

Material and Technology Integration

• Electrochromic Components:
  • Conductive Elements: Commonly use ITO as a transparent conductor.
  • Inks and Layers: Electrochromic inks and electrolytes facilitate the ion transfer necessary for color change.
• Thermochromic Mechanisms:
  • Heat Sources: Variably controlled through conductive traces or external heating tools like lasers or hair dryers.
  • Visual Changes: Often used in wearable technology to respond to body heat or environmental temperatures.
• Photochromic Techniques:
  • Control Methods: Utilize UV light for activation with tools ranging from simple UV LEDs to complex UV projectors for detailed patterning.

Summary

These advanced materials enable the creation of dynamic displays that respond to environmental stimuli such as light, heat, and electrical changes. Each technology offers unique opportunities for developing interactive and responsive interfaces across various applications.