Display Element Using Electro-Optic Effect for Low Voltage
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Solution Overview
Problem
Conventional liquid crystal display elements face limitations in response speed, viewing angle, and driving voltage, with TN mode displays being slow and having a narrow viewing angle, while FLC or AFLC modes offer high-speed response and wide viewing angles but are inadequate in shock resistance and temperature characteristics, and polymer dispersed liquid crystal displays have issues with response properties.
Innovation Solution
A display element with a medium that exhibits a change in degree of optical anisotropy in response to an electric field, using a pair of substrates with a medium held between them, where the electric field is applied parallel to the substrates, and a horizontal or vertical alignment film on one substrate, allowing for high-speed response and wide viewing angles without the need for precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If TN mode liquid crystal display element is used, then the display element is thin and consumes low power, but the response speed is slow and viewing angle is narrow
Solution Approach 1:
The patent changes the fundamental operating parameter from liquid crystal molecule rotation (TN mode) to optical isotropy change via electro-optic effect (Pockels or Kerr effect). This parameter change enables high-speed response (sub-millisecond to millisecond range) while maintaining low power consumption, as the new mechanism does not rely on viscous molecular rotation but on rapid electronic/orientational polarization response.
2Use of energy by moving object
If TN mode liquid crystal display element is used, then the display element is thin and consumes low power, but the viewing angle is narrow
Solution Approach 1:
The patent transitions from a system with fixed molecular alignment (TN mode with narrow viewing angle) to a system where optical isotropy changes dynamically via electro-optic effect. This enables wide viewing angle performance while maintaining low power consumption, as the optical properties respond to electric field without being constrained by molecular orientation geometry.
3Speed
If FLC or AFLC display mode is used, then high-speed response and wide viewing angle are achieved, but shock resistance and temperature characteristics are inadequate
Solution Approach 1:
The patent adopts electro-optic effect materials (exhibiting Pockels or Kerr effect) that operate through electronic or orientational polarization rather than ferroelectric switching. This parameter change provides high-speed response comparable to FLC/AFLC while achieving superior shock resistance and temperature characteristics, as the electro-optic mechanism is inherently more robust to mechanical and thermal stress.
4Speed
If FLC or AFLC display mode is used, then high-speed response and wide viewing angle are achieved, but irreversible alignment breakdown occurs due to external force
Solution Approach 1:
The patent changes from ferroelectric liquid crystal materials (which suffer from alignment breakdown) to materials exhibiting electro-optic effect (Pockels or Kerr effect). This parameter change eliminates the alignment stability problem while maintaining high-speed response, as the electro-optic mechanism does not rely on fragile molecular alignment that can break down under external force.
5Illumination intensity
If polymer dispersed liquid crystal display mode is used, then high-luminance display is achieved without polarizer, but response property deteriorates
Solution Approach 1:
The patent transitions from polymer dispersed liquid crystal mechanism (which has poor response properties) to electro-optic effect mechanism (Pockels or Kerr effect). This parameter change enables both high luminance display and high-speed response, as the electro-optic effect provides rapid optical modulation without the response limitations of polymer dispersed systems.
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
The solution enables a display device with reduced driving voltage, wider temperature range, and superior viewing angles, achieving high-speed response and improved display performance compared to conventional liquid crystal display elements.
Implementation Method 1
there has been suggested a liquid crystal display element using a material whose optical isotropy changes in response to electric field application, particularly a material causing orientational polarization due to electric optical effect, or electronic polarization
Implementation Method 2
The term 'electro-optic effect' indicates such a phenomenon that reflective index of a substance varies according to an external electric field, and there are two types in the electro-optic effect: (i) the Pockels effect that is proportional to the electric field, and (ii) the Kerr effect that is proportional to square of the electric field
Implementation Method 3
a horizontal or vertical alignment film provided on a second substrate of the pair of substrates
Data Source
AI summary
The subject invention provides a display element which achieves reduction in driving voltage. The display element according to the present invention includes substrates 1 and 2, at least one of which is transparent, and a medium layer 3 held between the substrates 1 and 2, the display element further including on the substrate 1 electrodes 4 and 5 for generating an electric field in a direction substantially parallel to the substrates so as to apply the electric field to the medium layer 3 to cause optical modulation of the medium; and an alignment film 6 which is provided on the surface of the substrate 2. With this arrangement, the voltage level is not decreased because of the alignment film 6, and the driving voltage of the display element does not need to be increased, thereby ensuring reduction of driving voltage.