Imaging Colorimeter DI Series

The DI Series is a high-performance area optical measurement instrument developed by FSTAR, specifically engineered for the Automatic Optical Inspection (AOI) of flat panel displays. It features a cooled image sensor to ensure high-quality imaging and integrates a built-in spectrometer optical path to maximize the accuracy of luminance and chromaticity measurements.

With resolutions ranging from 12MP to 61MP across different models, the DI Series is versatile enough to meet diverse and rigorous testing requirements.

Measurement Capabilities

The DI Series is designed to measure a comprehensive range of optical characteristics, including:

• Luminance & Chromaticity Uniformity: Including black state uniformity.
• Display Defects: Point/line defects, surface anomalies, and Mura.
• Image Retention: Third-order image retention and short-term image retention.
• Automotive Standards: Black Mura and HUD (Head-Up Display) optics.
• AR/VR: Optical characteristics for near-eye displays.
• Light Leakage: Detection of stray light in modules.

Key Features

Automated Image Signal Control (Mobile App)
Via Wi-Fi communication between the mobile app and PC, the system controls synchronous image switching. It completes the transition from a checkerboard pattern to the test pattern within 0.1 seconds, ensuring high speed and stability.

Electronic Lens Control
The hardware integrates a focusing drive module, enabling software-based electronic control of the focal length and the Electromagnetic Diaphragm (EMD). The system automatically adjusts exposure and parameters to optimize the test image, adapting effortlessly to different environments.

Dual-Layer Cooling System
The advanced cooling system minimizes measurement noise and signal drift, allowing for the precise analysis of weak light signals. By increasing gain, exposure time is kept within 100ms, significantly shortening measurement cycles.

High-Resolution Image Sensor
Equipped with a 14-bit CCD, the camera delivers exceptional luminance resolution. At a test luminance of 10 cd/m², it can distinguish luminance differences as small as 0.0024 cd/m², capturing a full image every second.

Built-in Spectrometer
An integrated spectrometer corrects and enhances the measurement accuracy of both luminance and chromaticity in real-time.

Factory Calibration
Each instrument is precision-calibrated before shipment. Variations in test distance, focal length, or aperture do not compromise the accuracy of luminance and chromaticity measurements.

Software Modules

Luminance & Chromaticity Analysis

• Core Measurement: Comprehensive analysis of luminance and chromaticity.
• Firefly Detection: Identification of transient bright spots.
• ROI Measurement: Targeted measurement of specific product areas.
• Advanced Analysis: Luminous cross-section, full-screen array, and ultra-low luminance analysis.

Short-Term Image Retention Test
Overcomes key measurement challenges through:

• Synchronous control of the Pattern Generator (PG) and software.
• High luminance resolution instrumentation.
• Ultra-short camera exposure times.
• Precise coordinate tracking for measurement points.

Spectral Analysis
Supports spectral calibration and can function as a standalone spectrometer for detailed spectral data.

Third-Order Image Retention Test
Compliant with the Display Area Sticking Image Standard (German Automotive OEM Work Group Displays, 2015), this module outlines and executes the testing methodology for third-order image retention.

Black Mura Test
Compliant with the Uniformity Measurement Standard for Displays V1.30 (German Automotive OEM Work Group Displays, 2018). Unlike SEMI D31, this standard focuses on Black Mura testing under black screen conditions, utilizing relative brightness gradient rather than contrast and area for calculation.

• Test Results Include:
  • White Screen: Average, max, and min luminance; uniformity.
  • Black Screen: Average, max, and min luminance; uniformity.

Head-Up Display (HUD) Optical Test
Essential for ensuring the safety and functionality of automotive HUD systems. The system verifies that projected information is clearly visible, correctly positioned, and distinct from the environment to prevent driver distraction.

• Measurement Items:
  • Virtual Image Distance (VID) & Size
  • Viewing Angle (δ) & Field of View (FOV)
  • Angular Resolution & Rotation Angle
  • Distortion
  • Luminance, Contrast, & Uniformity (under various ambient light conditions)

Character Test
Allows for individual ROI (Region of Interest) settings for character measurement.

• Criteria: Luminance uniformity, average luminance, chromaticity (x, y), and defect detection (missing, omitted, or incorrect characters).
• Capability: Supports simultaneous analysis of multiple characters or single-character breakdown.

Ambient Light & Light Guide Test
Designed for LED and light guide products where optical distribution requirements vary (e.g., uniformity vs. gradients). The system handles the microstructural and irregular shapes of light guides, ensuring consistent performance validation beyond simple uniformity metrics.

Sparkle Detection
Quantifies display "sparkle" (random moiré) caused by the interaction between pixel structures and Anti-Glare Layers (AGL).

• Method: Evaluates visual flicker, image clarity, and reflectance/transmittance against viewing direction (scattering distribution function) in compliance with Black Mura standards.

Pixel Analysis Measurement
Equipped with a microscopic lens, this module enables defect detection at the pixel and sub-pixel level.

• Results: Coordinates, max/min/average luminance, chromaticity (x, y), color difference (Δu’v’), and color temperature (Tc).

Backlit Keyboard Measurement
Detects luminance and chromaticity uniformity across backlit keyboards, including individual character analysis. Users can define measurement conditions and pass/fail criteria.

Display Defect Detection

• Panel Defects: Black/bright spots, lines (bright/dark/weak), foreign material, stains, image abnormalities, color shift, dents, and liquid crystal leakage.
• Backlight Module Defects: White/bright spots, debris, scratches, film displacement, light leakage, and shadows.

Mura & Light Leakage Detection
Algorithm based on the SEMI D31 standard for precise Mura and light leakage identification.

Typical Applications

• Consumer Electronics: Micro-displays, mobile phones, monitors, and large-size TVs.
• Automotive & Avionics: Dashboard displays, lighting systems, and HUDs.
• Components: Backlight modules and optical film testing.