OLED Print Head Current Sensing for Emission Defect Detection
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Solution Overview
Problem
Existing OLED print head devices lack an efficient and cost-effective method to detect defects in light emission/non-light emission of light emitting sources, which can lead to damage to the photoreceptor and developer due to vibration and movement, complicating the configuration and increasing costs when external detectors are used.
Innovation Solution
A print head device with a current detection circuit that detects the total driving current of light emitting sources, determining defects by comparing the current to a threshold value, allowing for inexpensive detection of light emission/non-light emission defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external detectors are used to detect defects in light emitting sources, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the defect detection function with the existing current detection circuit by having the controller analyze current values to determine light emission status. This integrates detection capabilities into the existing system rather than adding separate external detectors, thereby maintaining reliability while reducing device complexity and cost.
Solution Approach 2:
The system uses its own current detection circuit to detect defects in light emitting sources without requiring external detection equipment. The controller utilizes the already-present current detection functionality to monitor light emission status, allowing the system to self-diagnose defects without additional components.
2Measurement precision
If external detectors are used to detect defects in light emitting sources, then detection precision is improved, but cost increases
Solution Approach 1:
The patent combines the defect detection function with the existing current detection circuit, eliminating the need for separate external detectors. This merging approach maintains detection precision through current analysis while significantly reducing manufacturing costs by utilizing already-present circuitry.
Solution Approach 2:
The system uses the existing current detection circuit (designed for other purposes) to perform defect detection by analyzing current patterns. This repurposing of existing circuitry provides accurate defect detection without the cost of dedicated detection hardware.
3Manufacturing precision
If light emitting sources are arranged at high density corresponding to pixel count, then resolution is improved, but detection of individual defects becomes more difficult
Solution Approach 1:
The patent replaces optical or physical inspection methods with electrical current analysis for defect detection. By substituting mechanical/optical detection with electrical measurement of current values, the system can efficiently detect defects in high-density arrangements without the complexity of inspecting each closely-spaced light emitting source individually.
Solution Approach 2:
Each light emitting source's operational status is determined through analysis of its own current consumption characteristics. The system uses electrical properties inherent to each component to self-diagnose defects, enabling individual defect detection in high-density arrangements without requiring external inspection equipment.
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 reliable and cost-effective detection of defects in light emitting sources, preventing damage to the photoreceptor and developer, and simplifying the device configuration by reducing the need for external detectors.
Implementation Method 1
a light-emitting element that emits light at luminance corresponding to a current
Implementation Method 2
a current detection circuit that detects a total driving current of all or a plurality of the light emitting sources
Data Source
AI summary
A print head device including: an active light emitter including light emitting sources formed in at least one row, the light emitting sources each including a drive element and a light-emitting element which emits light at luminance according to a driving current caused to flow by the drive element; a controller that controls each drive element to control light emission and non-light emission of each light emitting source, and luminance during the light emission; and a current detection circuit that detects magnitude of a current, wherein the current detection circuit detects a total driving current of all or a plurality of the light emitting sources as target light emitting sources, and the controller brings the target light emitting sources into a light emitting state, and thereafter determines that the target light emitting sources are defective in a case where the driving current detected by the current detection circuit is less than a predetermined first threshold value.