Liquid Crystal Phase Shifter Spacers for Thick Cell Uniformity

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Solution Overview

Problem

Existing liquid crystal phase shifters face challenges in achieving uniform cell thickness due to limitations in spacer thickness, leading to deformation and poor performance, as current manufacturing methods struggle to produce spacers thicker than 100 µm, resulting in inadequate dielectric loss reduction and inconsistent phase modulation.

Innovation Solution

The use of epoxy or UV glue as spacers arranged on both substrates, with hot-press curing to form a housing of predetermined thickness, ensuring the liquid crystal layer thickness is maintained at 100-250 µm, and the spacers are evenly distributed to support the substrates, enhancing the phase shifter's performance and manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If plastic ball spacers are used with current spraying methods, then manufacturing is simple, but spacer thickness cannot reach 100 µm and uniform distribution is poor

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidspacer thickness and uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from plastic balls to photoresist material, and changes the thickness parameter from 30 µm maximum to 100 µm or above, while maintaining screen printing as the manufacturing method. This allows achieving both manufacturing simplicity and the required thickness precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses photoresist material combined with screen printing technology to create composite spacers that achieve both the required thickness (100 µm+) and uniform distribution, resolving the contradiction between ease of manufacture and manufacturing precision.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If photoresist is used with spin-coating process, then uniform coating is achieved, but spacer thickness is limited to 6-15 µm

Engineering Contradiction:
Improvecoating uniformityVSAvoidspacer thickness
Core Design Contradiction:
Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent merges the advantages of photoresist material (uniform coating capability) with screen printing technology (thickness control), creating a hybrid approach that achieves both coating uniformity and the required spacer thickness of 100 µm or above.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the process parameter from spin-coating to screen printing, which enables thickness control at 100 µm or above while maintaining the uniformity benefits of photoresist material.

Inventive Principle:
Principle #35Parameter changes

3Length of stationary object

If sealant with high viscosity is used in screen printing, then spacer thickness can reach 100 µm or above, but manufacturing complexity increases

Engineering Contradiction:
Improvespacer thicknessVSAvoidmanufacturing process complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent changes the material parameter from high viscosity sealant to photoresist material, which can be applied at lower viscosity and then cured to achieve the required thickness, thereby reducing manufacturing process complexity while maintaining spacer thickness of 100 µm or above.

Inventive Principle:
Principle #35Parameter changes

4Loss of energy

If cell thickness is increased to 100-250 µm, then dielectric loss is reduced, but spacer thickness requirement becomes 100 µm or above which is difficult to manufacture

Engineering Contradiction:
Improvedielectric lossVSAvoidspacer manufacturing
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The patent uses photoresist material combined with screen printing to create spacers that are both manufacturable (using existing screen printing infrastructure) and thick enough (100 µm+) to support the 100-250 µm cell thickness required for low dielectric loss.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the spacer material and process parameters to enable thickness of 100 µm or above, which directly supports the cell thickness increase needed to reduce dielectric loss, while maintaining ease of manufacture through screen printing.

Inventive Principle:
Principle #35Parameter changes

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 allows for the production of liquid crystal phase shifters with consistent thickness and improved performance by ensuring the spacers and sealants are precisely arranged and cured, facilitating large-scale manufacturing of high-performance devices with reduced dielectric loss.

Implementation Method 1

the relationship between liquid crystal dielectric loss and liquid crystal cell thickness

Methodology Applied
Scientific EffectDielectric effect: Dielectric

Implementation Method 2

A phase shifter is a device which can adjust the phases of electromagnetic waves

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Implementation Method 3

The use of epoxy or UV glue as spacers arranged on both substrates, with hot-press curing

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3736625B1Liquid crystal phase shifter and method for fabrication thereof
Publication Date: 2024.10.09 TRULY SEMICON
  • EP3736625B1 patent drawingFigure 1~2
  • EP3736625B1 patent drawingFigure 3

AI summary

The present disclosure provides a liquid crystal phase shifter, comprising a first substrate and a second substrate which are oppositely arranged, and a liquid crystal layer positioned between the first substrate and the second substrate, wherein a plurality of spacers are distributed in the liquid crystal layer, the spacers are in contact with the first substrate and the second substrate, and include a first spacer arranged on the first substrate and a second spacer arranged on the second substrate, and the first spacer and the second spacer are abutted. The present disclosure also provides a manufacturing method of the liquid crystal phase shifter. The first spacer and the second spacer are arranged on the first substrate and the second substrate respectively, so that the thickness of a support of the liquid crystal phase shifter being 100 µm or above is realized, and the performance of the liquid crystal phase shifter is ensured. Besides, the liquid crystal phase shifter is easy to manufacture, and the liquid crystal phase shifter with the thick cell can be manufactured on a large scale.