Ferroelectric Liquid Crystal Modulator High-Speed Switching

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Solution Overview

Problem

In structured illumination microscopes, increasing the time for applying reverse voltage reduces the frame rate for acquiring images, which is a limitation in achieving high-speed switching of structured illumination.

Innovation Solution

A structured illumination microscope design that includes a light modulator with ferroelectric liquid crystals, where voltage patterns are alternated between positive and negative voltages within each frame period to prevent image burn-in and maintain high-speed switching, allowing for efficient acquisition of modulated images without reducing frame rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reverse voltage is applied for a longer time to prevent image burn-in, then image quality is maintained, but frame rate decreases

Engineering Contradiction:
Improveimage qualityVSAvoidframe rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies periodic alternating voltage patterns to the SLM, switching between different voltage states within each frame period. This periodic action prevents charge accumulation that causes image burn-in while maintaining high frame rates, as the voltage reversal occurs rapidly enough not to interrupt the imaging process.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically changes the voltage parameters applied to the SLM, specifically alternating between positive and negative voltage patterns. By modifying the voltage state periodically rather than maintaining a constant DC bias, the system prevents ion migration in the ferroelectric liquid crystal while preserving image quality and maintaining high-speed operation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If voltage patterns are inverted frequently to prevent image burn-in, then image quality is maintained, but the complexity of voltage control increases

Engineering Contradiction:
Improveimage qualityVSAvoidvoltage control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the voltage pattern applied to the SLM between consecutive frames or within a frame period. By applying a negative voltage pattern after a positive one (or vice versa), the system counteracts charge accumulation and prevents image burn-in. This inversion strategy is implemented through straightforward control logic that alternates voltage polarity, avoiding complex control mechanisms.

Inventive Principle:
Principle #13The other way round (Inversion)

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

This approach enables the structured illumination microscope to maintain high frame rates while preventing image burn-in, allowing for effective high-speed switching and efficient image acquisition, thereby improving the microscope's operational efficiency.

Implementation Method 1

a light modulator that includes a first substrate on which a plurality of pixel electrodes are provided, a second substrate opposed to the first substrate, and a ferroelectric liquid crystal disposed between the first substrate and the second substrate

Methodology Applied
Scientific EffectFerroelectric liquid crystal effect: Liquid Crystals

Implementation Method 2

The SLM applies voltage having positive potential and voltage having negative potential to the pixel electrodes. When the temporal sum of potential difference between the first substrate and the second substrate is not 0, that is, when a DC component of voltage is present, internal ions of ferroelectric liquid crystals are attracted in one direction

Methodology Applied
Scientific EffectElectro-optic modulation: Electro-Optic Effects

Implementation Method 3

This method involves branching a beam that has been emitted from a light source into a plurality of beams with a diffraction grating or the like, and illuminating a sample with interference fringes formed by causing the beams to interfere with each other in the sample

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 4

illuminating a sample with interference fringes formed by causing the beams to interfere with each other in the sample

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP3367151B1Structured illumination microscope, observation method, and microscope control program
Publication Date: 2024.07.17 NIKON CORP
  • EP3367151B1 patent drawingFigure 1
  • EP3367151B1 patent drawingFigure 2(A)~2(B)
  • EP3367151B1 patent drawingFigure 3(A)~3(B)

AI summary

Provided is a structured illumination device capable of switching structured illumination at high speed. A structured illumination microscope (2) includes: a brancher (13) that includes a first substrate on which a plurality of pixel electrodes are provided; a second substrate opposed to the first substrate; and a ferroelectric liquid crystal disposed between the first substrate and the second substrate, and branches light from a light source (20) into diffracted light beams; an illumination optical system (14) that illuminates a sample with interference fringes formed by at least some of the diffracted light beams; an imaging device (3) that forms an image of the sample irradiated with the interference fringes; a demodulator (4); and a controller (15) that controls a direction and a phase of the interference fringes. In one frame period during which the imaging device takes the image, the controller (15) applies a first voltage pattern and a second voltage pattern obtained by inverting the first voltage pattern to at least some of the pixel electrodes.