Thin Plastic AMLCD Manufacturing via Lift-Off Carrier
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current manufacturing methods for active matrix liquid crystal displays (AMLCDs) on plastic substrates face challenges such as substrate shrinkage, handling difficulties, and high costs due to the need for new equipment and hazardous chemical use, while integrating color filters into the active plate is hindered by alignment accuracy and material degradation issues.
Innovation Solution
A method involving the formation of pixel circuits on a rigid carrier substrate with a plastic substrate, using a lift-off process to release the carrier and create channels for color filters, allowing for ink jet printing and improved alignment and optical aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass substrates are used for AMLCD manufacturing, then mechanical strength and handling ease are improved, but device thickness and weight increase
Solution Approach 1:
The patent segments the substrate system into two parts: a thick glass carrier substrate for mechanical strength during manufacturing, and a thin plastic substrate for the final display. The glass substrate is etched with channels that allow the plastic substrate to be released and form the final thin display structure, thus separating the manufacturing support function from the final product requirements.
Solution Approach 2:
The patent extracts the mechanical strength function from the final display product by using a separate glass carrier substrate that is removed after manufacturing. The glass substrate provides strength during TFT fabrication and color filter integration, then is etched away through channels to release the thin plastic substrate for the final thin display.
2Area of moving object
If color filters are integrated into the active plate, then optical aperture is improved, but alignment accuracy and material degradation occur
Solution Approach 1:
The patent performs preliminary action by integrating color filters into the active plate before final assembly, while the active plate is still supported on the glass carrier substrate. This preliminary integration allows for better alignment control during manufacturing, and the glass substrate provides mechanical support that prevents material degradation during subsequent processing steps.
Solution Approach 2:
The glass carrier substrate acts as an intermediary that provides mechanical support during color filter integration. It enables precise alignment and prevents plastic substrate deformation or damage during the color filter deposition process, thereby achieving both high optical aperture and alignment accuracy.
3Weight of stationary object
If plastic substrates are used directly without glass carrier, then device thickness is reduced, but manufacturing complexity and handling difficulty increase
Solution Approach 1:
The manufacturing process is segmented into two phases: first, manufacturing on the glass carrier substrate using conventional processes; second, releasing the plastic substrate through etched channels and completing assembly. This segmentation allows standard manufacturing equipment to be used initially, then transitions to specialized release processes, reducing overall manufacturing complexity.
Solution Approach 2:
The glass carrier substrate serves as an intermediary that enables the use of conventional manufacturing equipment and processes for TFT fabrication. It provides mechanical strength for standard handling, photolithography, and assembly operations, which would be difficult or impossible with thin plastic substrates alone.
4Weight of stationary object
If HF etching is used for glass thinning, then device thickness is reduced, but hazardous chemical use and yield loss increase
Solution Approach 1:
The patent extracts the thinning function from the final display product by performing glass etching during the manufacturing phase on the carrier substrate, not on the final thin display. The glass is etched with channels that are later used to release the plastic substrate, eliminating the need for hazardous HF etching of the final thin cell.
Solution Approach 2:
The glass carrier substrate is treated as a disposable manufacturing aid that is etched and discarded after serving its purpose. It provides mechanical strength during manufacturing, then is etched away through controlled channels to release the final product, avoiding the need to preserve or carefully handle thin glass in the final display.
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 the production of thin, lightweight, and cost-effective AMLCDs with enhanced optical aperture and reduced environmental impact, addressing the fragility and yield loss issues of existing methods.
Implementation Method 1
using a lift-off process to release the carrier and create channels for color filters
Data Source
Figure 1~3
Figure 4~5
Figure 6A~6C
AI summary
A method of manufacturing a colour active matrix display device comprises forming islands over a rigid carrier substrate, forming a plastic substrate over the rigid carrier substrate, forming an array of pixel circuits over the plastic substrate and forming a display layer over the array of pixel circuits. The rigid carrier substrate is then released from the plastic substrate and the plastic substrate then has channels defined by the islands. These are filled to define colour filter portions. The formation of a plastic substrate on a rigid carrier, with the use of a subsequent lift off process, enables the circuit arrays to be made on very thin plastic sheets. The colour filters can then be made on the outside of the LC cell. Depressions are formed in the plastic substrate registered to the circuit array, and these are filled in with colour filter material, for example by ink jet printing.