Droplet Inspection Module Using Real-Time Sensor Adjustment

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Solution Overview

Problem

Conventional droplet inspection systems for ink jet heads face hardware interference and limited inspection area, leading to inaccurate measurements and increased setup time due to the need for high-magnification lenses with curved optical systems, which are prone to focus issues and require extensive movement to inspect multiple nozzles.

Innovation Solution

A droplet inspection module comprising a TOF sensor and a variable lens that adjusts operating distance in real-time, combined with a high-resolution camera and RGB illumination, allowing for accurate droplet inspection without hardware interference and enabling efficient inspection of multiple nozzles without the need for extensive movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high-magnification lens is used to inspect the droplet, then the measurement precision is improved, but the device complexity increases and hardware interference occurs

Engineering Contradiction:

Improvedroplet measurement precisionVSAvoidoptical system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical optical system (lens and illumination part forming a curve) with a sensor-based measurement system. The sensor measures the droplet directly without requiring complex optical components, thereby eliminating hardware interference and reducing device complexity while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the measurement function from the complex optical system and implements it through a separate sensor that measures the droplet distance directly. This separates the measurement capability from the imaging system, eliminating the need for curved optical arrangements and reducing overall system complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If a high-magnification lens is used to inspect the droplet, then the measurement precision is improved, but the reliability decreases due to focus issues

Engineering Contradiction:

Improvedroplet measurement precisionVSAvoidfocus stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the optical focusing system with a sensor-based distance measurement system. The sensor directly measures the droplet position without requiring optical focusing, eliminating focus issues and improving measurement reliability while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the lens and illumination part form a curve in the optical system, then the measurement precision is improved, but the ease of operation worsens due to increased setup time

Engineering Contradiction:

Improvedroplet measurement precisionVSAvoidsetup time

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the curved optical system with a linear sensor arrangement that measures droplet distance directly. This eliminates the need for precise optical alignment and curved component positioning, significantly reducing setup time and improving ease of operation while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If the inspection apparatus moves to inspect multiple nozzles, then the productivity is improved, but the loss of time increases due to movement requirements

Engineering Contradiction:

Improveinspection throughputVSAvoidmovement time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent implements a sensor system that can measure multiple nozzles simultaneously or in rapid succession without requiring physical movement of the inspection apparatus. The system serves itself by maintaining a fixed position while capturing data from all nozzles, eliminating movement time and improving inspection throughput.

Inventive Principle:

Principle #25Self-service

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

The solution enables clear determination of droplet presence and amount, reduces setup time, and improves image quality by eliminating focus issues and expanding the field of depth, allowing for efficient inspection of all nozzles with reduced Tact Time Loss and improved image clarity.

Implementation Method 1

a sensor located under the ink jet head and measuring a distance between the droplet and the sensor in real time; The sensor may be a TOF (Time of Flight) sensor

Methodology Applied

Scientific EffectTime of Flight: Time of Flight

Data Source

PatentUS11338578B2Droplet inspection module and droplet inspection method

Publication Date: 2022.05.24 SYSTEM ENGINEERING MEGA SOLUTION CO LTD

AI summary

An inspection module is disclosed for inspecting a droplet from an ink jet head. The inspection module includes a sensor located under the ink jet head and measuring a distance between the droplet and the sensor in real time; a variable lens changing an operating distance based on the measured distance of the sensor; and a camera for capturing an image of the droplet. The inspection module further includes a droplet inspecting part inspecting the droplet image captured by the camera.