Liquid Crystal Iris with Dichroic Particles for Low-Loss Light Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical devices using liquid crystals face issues with high light loss due to polarizers and limited ability for intensity modulation with high contrast or variable iris operation.
Innovation Solution
A device with a liquid crystal orienting matrix and dichroic particles, controlled by an electric field generator with a spatially non-uniform profile, allows for dynamic adjustment of the cross-sectional area for light transmission, using a layered structure with optically transparent substrates and frequency-dependent materials to change the effective shape of electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two polarizers are used in the liquid crystal shutter, then light transmission can be controlled, but light loss increases significantly
Solution Approach 1:
The patent removes one or both polarizers from the traditional liquid crystal shutter configuration. Instead of using polarizers to control light transmission, the invention uses a single polarizer combined with a liquid crystal layer that can rotate its optical axis, or uses dichroic particles dispersed in the liquid crystal matrix to provide polarization-dependent absorption without requiring two polarizers.
Solution Approach 2:
The patent changes the control mechanism from polarizer rotation or insertion/extraction to liquid crystal molecular reorientation. By applying electric fields to change the orientation of liquid crystal molecules or dichroic particles, the optical properties (transmission/absorption) are controlled dynamically without mechanical movement of polarizers, thereby reducing light loss.
2Device complexity
If a uniform liquid crystal cell with two uniform electrodes is used, then the structure is simple, but intensity modulation with high contrast and variable iris operation cannot be achieved
Solution Approach 1:
The patent introduces spatially non-uniform electrode patterns (such as hole-patterned electrodes or segmented electrodes) that create localized electric fields in specific regions of the liquid crystal cell. This allows different areas of the cell to have different optical properties, enabling variable iris operation and regional intensity modulation while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent makes the electrode configuration dynamically controllable through electronic means. By applying different voltage patterns to different electrode segments or regions, the optical characteristics can be dynamically adjusted to achieve variable iris operation and high-contrast intensity modulation without mechanical components.
3Adaptability or versatility
If electrowetting liquid lenses are used to form tunable light shutters, then focal length can be adjusted, but light loss increases and high contrast intensity modulation is limited
Solution Approach 1:
The patent replaces the electrowetting lens mechanism with a liquid crystal-based optical modulation system. Instead of changing focal length through surface tension control, the invention uses liquid crystal molecular reorientation or dichroic particle alignment to directly modulate light transmission and absorption, achieving high-contrast intensity control without the optical losses associated with electrowetting lenses.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient light control with minimal obstruction, allowing for variable iris or eclipse shapes and wavelength-dependent light transmission, reducing light loss and enhancing contrast modulation.
Implementation Method 1
A liquid crystal orienting matrix layer is located between the optical input and the optical output, and a plurality of dichroic particles is dispersed within it. The dichroic particles are influenced by proximate molecules of the liquid crystal matrix such that reorientation of the proximate liquid crystal molecules results in reorientation of the dichroic particles.
Implementation Method 2
An electric field generation system (or 'generator') is used to provide an electric field across the liquid crystal layer that has a dynamically variable spatial profile. This creates a spatially non uniform field strength that causes a reorientation of liquid crystal molecules mainly within a predetermined cross section of the liquid crystal layer.
Implementation Method 3
In a first orientation, the dichroic particles cause no significant obstruction of light between the optical input and the optical output, while in a second orientation they create a significant obstruction of the light.
Data Source
AI summary
An apparatus for controlling light transmission from an optical input to an optical output can function as a tunable iris or eclipse, or as a privacy window. The iris/eclipse can use a liquid crystal matrix with a dispersion of dichroic particles that absorb light in one orientation and transmit light in another, such that controlling the liquid crystal with an electric field allows control of the dichroic particles. Alternatively, a layer may be used with a light absorbing liquid or powder material that moves with a charged material in response to a variable electric field applied to the layer. Privacy windows use a plurality of liquid crystal microlenses that can be controlled with an electric field to allow an image of an optical input to be obtainable at an optical output when in a first state, or to render the image irretrievable when in a second state.