COG OLED Display Module Design Manual 

┃What Is a COG OLED Display Module?

A COG (Chip On Glass) OLED display module integrates the driver IC directly onto the glass substrate of the OLED panel. This integration minimizes PCB space requirements and enhances power efficiency. These modules offer high-contrast output, wide viewing angles, and accurate color reproduction. Applications include industrial HMI, embedded systems, consumer electronics, and IoT devices. Compared to LCDs, OLEDs offer superior black levels and higher pixel sharpness. The thin, lightweight nature of COG OLED modules makes them optimal for compact device designs and power-sensitive applications. 

Key Features

• Resolution: Customizable depending on application requirements.

• Display Mode: Supports single-color or dual-color display variants.

• Interface Support: Compatible with I2C and SPI communication protocols.

• Contrast Ratio: High contrast for enhanced visual clarity.

• Brightness Control: Select models support brightness adjustment for optimal visibility.

┃Interface

The COG OLED Display Module supports multiple mainstream communication interfaces, offering greater integration flexibility across various system platforms:

• Parallel (6800 / 8080): Utilizes parallel transmission, ideal for applications requiring faster response times, and highly compatible with traditional MCU systems.

• I²C (Inter-Integrated Circuit): Requires only two signal lines (SCL and SDA), making it suitable for compact controllers with limited I/O pins, and supports multi-device bus sharing.

• SPI (Serial Peripheral Interface): Offers 3-wire or 4-wire modes, providing high-speed transmission and straightforward control logic, ideal for high-speed or space-constrained applications.

The module comes with standard interface options by default, and can be customized or switched based on the host platform and user requirements.

┃Recommendations

To fully leverage the advantages of COG OLED display modules, we recommend the following design guidelines:

• Power/Input Interface: Operate within 3.3V–5V supply range. Select communication protocols (I2C/SPI) based on MCU compatibility to ensure reliable data exchange.

• Brightness Control: For modules supporting backlight, implement PWM dimming to adapt brightness per ambient light levels. This improves visibility and extends operational life.

• Driver and Software Support: Select appropriate drivers that are compatible with both the display module and the main control unit. For graphical displays, consider using suitable graphics libraries to support image rendering.

• Environmental Consideration: Design for the module’s operating temperature range (typically -40°C to 85°C) based on usage scenarios. For humid environments, moisture-proofing measures are recommended to protect the display.

• Mechanical/Dimensional Design: Choose a module size that fits the application, and incorporate mechanical protection—such as a protective layer—to prevent physical damage.

┃Product Overview

COG (Chip on Glass) OLED modules feature integrated driver ICs mounted directly on the glass substrate, enabling a thinner profile and improved reliability. The absence of a backlight minimizes power consumption and saves space, while enhancing contrast ratio and viewing angles. These modules are well-suited for applications requiring compact and high-performance displays, such as industrial control panels, medical instruments, smart appliances, and handheld terminals.

Eileen Technology offers a comprehensive specification sheet covering dimensions, resolutions, interface types (I²C/SPI), operating voltages, pin configurations, and controller IC details to support efficient comparison and precise model selection during development.

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