Tiled Display Pixel Circuits for PAM and PWM Testing
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Solution Overview
Problem
Existing display devices and tiled display devices lack effective methods for electrically testing the PAM and PWM circuits of pixel circuits, which are crucial for ensuring proper operation.
Innovation Solution
The display device and tiled display device incorporate first and second sub-pixels connected to different global data lines, each with a circuit to supply and control a driving current, and include a test transistor connected to the anode of the light emitting element, allowing for electrical testing of both PAM and PWM circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a tiled display device is used to enlarge the display area, then the display size is improved, but the complexity of electrical testing for pixel circuits increases
Solution Approach 1:
The patent divides the pixel circuit into separate functional blocks: a PAM circuit for amplitude modulation and a PWM circuit for pulse width modulation. Each circuit is independently testable through dedicated test transistors and test nodes, allowing complex tiled displays to be tested systematically without overwhelming complexity
Solution Approach 2:
The patent introduces test transistors as intermediary components that provide dedicated test paths from the pixel circuit to external test nodes. These test transistors act as mediators that enable electrical testing without interfering with the normal display function, allowing comprehensive testing of both PAM and PWM circuits in tiled display configurations
2Reliability
If comprehensive electrical testing of PAM and PWM circuits is implemented, then the reliability of pixel circuits is improved, but the device complexity increases
Solution Approach 1:
The pixel circuit is segmented into distinct PAM and PWM functional blocks with separate test transistors for each. This segmentation allows independent testing of each circuit type, improving reliability through comprehensive testing while managing complexity through modular architecture
Solution Approach 2:
The test transistor serves multiple functions: it provides a test path for PAM circuit testing, enables PWM circuit testing, and can be configured for different test modes. This multi-functionality allows comprehensive reliability testing without proportionally increasing device complexity
Data Source
AI summary
A display device includes: first sub-pixels commonly connected to a first global data line, each including a first light emitting element to emit light of a first color; and second sub-pixels commonly connected to a second global data line different from the first global data line, each including a second light emitting element to emit light of a second color different from the first color. At least one of the first sub-pixels includes: a first circuit to supply a driving current to the first light emitting element based on a first global data voltage received from the first global data line; a second circuit to control a supply period of the driving current based on a data voltage received from a data line; and a test transistor including a first electrode connected to an anode of the first light emitting element, and a second electrode connected to the data line.