Chiplet Optical Testing for Display Manufacturing
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Solution Overview
Problem
Existing active-matrix light-emissive displays face performance limitations and manufacturing inefficiencies due to the use of thin-film semiconductor materials, leading to non-uniformity and high costs, with current testing methods being time-consuming and inefficient, especially for high-definition displays.
Innovation Solution
The implementation of chiplets with independent substrates, each containing a pixel control circuit and a test light emitter, allows for efficient testing and control of light-emitting diodes by emitting light in response to external signals, enabling detection of faulty chiplets and interconnections, and improving the performance of control elements in flat-panel displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thin-film semiconductor materials are used for control elements, then manufacturing cost is reduced and integration is improved, but device performance and uniformity deteriorate
Solution Approach 1:
The patent divides the control element into two separate components: a thin-film transistor array on a first substrate for control functions, and a discrete chiplet on a second substrate for signal processing. This segmentation allows each component to be optimized independently - the thin-film transistor benefits from low-cost manufacturing while the chiplet provides high-performance processing, thereby resolving the contradiction between manufacturing ease and device reliability.
2Ease of manufacture
If thin-film semiconductor materials are used for control elements, then integration is improved, but non-uniformity increases
Solution Approach 1:
The patent introduces a discrete chiplet as an intermediary component between the thin-film transistor array and the display pixels. The chiplet serves as a mediator that receives control signals from the thin-film transistor, processes them with high precision, and drives the pixels. This intermediary approach allows the thin-film transistor to maintain its integration advantages while the chiplet compensates for uniformity issues through precise signal processing.
3Reliability
If conventional testing methods are used, then all connections can be tested, but testing time increases
Solution Approach 1:
The patent implements preliminary optical testing of the chiplet-to-substrate connections before final assembly. By using optical methods to pre-test connections, the system can identify and correct issues early in the manufacturing process, reducing the need for time-consuming electrical testing of every connection after assembly. This preliminary action maintains testing completeness while significantly reducing overall testing time.
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 enhances the performance of control elements and provides a rapid, efficient method for testing chiplets and electrical connections during manufacturing, improving yield and reducing costs by identifying and repairing flaws early in the process.
Implementation Method 1
one or more test light emitters formed in the chiplet responsive to the current provided on the control electrodes to emit light
Data Source
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AI summary
A method of making a display includes providing a display substrate having a plurality of control electrodes in a display area; locating a plurality of chiplets responsive to a controller to provide current to the control electrodes, each duplet having a separate substrate, at least one pixel connection pad electrically connected to a control electrode, and one or more test light emitters formed in the chiplet responsive to the current provided on the control electrodes to emit light; controlling the chiplets to pass current through one or more of the test light emitters formed in the chiplet to emit light; detecting the light emitted by the test light emitters to determine faulty chiplets or chiplet interconnections; replacing or repairing the faulty chiplets or chiplet interconnections; and forming an organic light emitting diode over the substrate in the display area connected to the control electrodes.