Arduino Tutorial: 0.96-Inch OLED Display

Arduino Tutorial: 0.96-Inch OLED Display

Experiment: 0.96 inch I2C IIC Communication 128*64 Display OLED LCD Screen Module

OLED, which stands for Organic Light-Emitting Diode and is also known as Organic Electroluminescence Display, is a type of current-driven organic light-emitting device. It produces light by injecting and recombining charge carriers, with the light intensity being directly proportional to the injected current. Under an electric field, holes created at the anode and electrons generated at the cathode move towards the hole transport layer and electron transport layer, respectively, eventually reaching the light-emitting layer. There, they form excitons that excite light-emitting molecules to emit visible light.

Typically, OLEDs are categorized into two types based on their emissive materials: small molecule OLEDs and polymer OLEDs (also called PLEDs). OLED technology uses multiple layers of organic thin films to achieve electroluminescence, allowing for easy fabrication and low driving voltages. These features make OLEDs particularly advantageous for flat-panel display applications. Compared to LCDs, OLED displays are thinner, lighter, offer higher brightness, consume less power, have faster response times, provide superior clarity, possess good flexibility, and exhibit high luminous efficiency, meeting consumers' modern demands for display technologies. As more display manufacturers invest in research and development globally, the industrialization and adoption of OLED technology have accelerated significantly.

Characteristics of OLED

(1) Low power consumption - Compared to LCDs, OLEDs do not require a backlight source, which is a relatively energy-consuming part in LCDs, making OLEDs more energy-efficient. For example, a 24-inch AMOLED module consumes only 440mW, while a 24-inch polysilicon LCD module reaches 605mW.

(2) Fast response time - OLED technology has a fast response time compared to other technologies, with response times reaching the microsecond level. The higher response speed better achieves motion images. According to relevant data analysis, its response speed is approximately 1000 times faster than that of liquid crystal displays.

(3) Wide Viewing Angles: Unlike other displays, OLED screens maintain image quality over a wide range of viewing angles because they actively emit light. Both the vertical and horizontal viewing angles extend beyond 170 degrees without distortion.

(4) High-resolution display capability - Most high-resolution OLED displays use active matrix organic light-emitting diode (AMOLED) technology, which can absorb up to 260,000 true colors of high resolution. With the advancement of science and technology, OLED resolutions are expected to increase further in the future.

(5) Wide Temperature Range: Unlike LCDs, OLEDs can function across a broad range of temperatures. Technical analyses indicate that OLEDs operate effectively between -40 degrees Celsius and 80 degrees Celsius. This capability reduces geographical limitations, enabling normal use even in extremely cold regions.(6) OLED enables flexible screens - OLED technology can be produced on various flexible substrate materials such as plastic and resin. By depositing or coating organic layers on flexible substrates, OLEDs can achieve flexible screens.

(7) Lighter weight of OLED finished products - Compared to other products, OLEDs have a smaller footprint and thickness than LCDs. They have a higher resistance coefficient, able to withstand greater accelerations, vibrations, and harsh environments.

OLED Structure

The structure of an OLED includes several key components such as the substrate, cathode, anode, hole injection layer (HIL), electron injection layer (EIL), hole transport layer (HTL), electron transport layer (ETL), electron blocking layer (EBL), hole blocking layer (HBL), and emissive layer (EML). The substrate acts as the device's foundation, onto which all functional layers are deposited. Glass is typically used as the substrate material, but for flexible OLED devices, materials like plastic may be employed. The anode connects to the positive terminal of the external driving voltage applied to the device, allowing holes from the anode to move toward the emissive layer under this voltage. The anode must be somewhat transparent during operation to allow emitted light to be visible externally, with ITO being the most commonly used material for this purpose.

The hole injection layer modifies the anode to facilitate smooth injection of holes into the hole transport layer, which then carries these holes to the emissive layer. The electron blocking layer prevents electrons from reaching the emissive layer interface, thereby increasing their concentration there. The emissive layer is where electrons and holes recombine to form excitons that emit light. The hole blocking layer stops holes at the emissive layer interface to enhance electron-hole recombination probability, boosting the device's luminous efficiency. The electron transport layer conveys electrons from the cathode to the emissive layer, while the electron injection layer modifies the cathode to transfer electrons to the electron transport layer. Electrons from the cathode travel towards the emissive layer under the influence of the external driving voltage and recombine with holes from the anode within the emissive layer.

Principle of Luminescence

The luminescent process of OLED devices can be divided into: injection of electrons and holes, transmission of electrons and holes, recombination of electrons and holes, and exciton excitation light emission. Specifically:

(1) Injection of Electrons and Holes: Under the driving voltage, electrons from the cathode and holes from the anode move towards the device's light-emitting layer. During this process, if an electron injection layer and a hole injection layer are present, electrons and holes must first overcome the energy barriers between the cathode and the electron injection layer, as well as between the anode and the hole injection layer. They then pass through these layers to reach the electron transport layer and hole transport layer of the device. The electron injection and hole injection layers enhance the device's efficiency and lifespan. The mechanism of electron injection in OLED devices is still under investigation, with the tunneling effect and interface dipole mechanism being most commonly used.

(2) Transmission of Electrons and Holes: Driven by the voltage, electrons from the cathode and holes from the anode move to the electron transport layer and hole transport layer, respectively. These layers then carry the electrons and holes to the interface of the device's light-emitting layer. At the same time, the electron transport layer and hole transport layer block holes from the anode and electrons from the cathode at the light-emitting layer interface, allowing electrons and holes to accumulate there.

(3) Recombination of electrons and holes. When a certain number of electrons and holes at the interface of the light-emitting layer of the device are reached, electrons and holes will recombine to form excitons in the light-emitting layer.

(4) Light emission due to exciton de-excitation. Excitons generated in the light-emitting layer will activate the organic molecules in the light-emitting layer of the device, causing the outermost electrons of the organic molecules to transition from the ground state to the excited state. Since the electrons in the excited state are highly unstable, they will transition back to the ground state, releasing energy in the form of light during the transition, thereby achieving device illumination.

Comparison between OLED and LED/LCD

1. Compared to the crystal layer of LED or LCD, the organic plastic layer of OLED is thinner, lighter, and more flexible.
2. The light-emitting layer of OLED is relatively light, allowing for the use of flexible materials in its base layer, rather than rigid materials. While OLED's base layer is made of plastic, LED and LCD use glass substrates.
3. OLED is brighter than LED. The organic layer of OLED is much thinner than the corresponding inorganic crystal layer in LED, allowing OLED's conductive and emitting layers to be multi-layered. Additionally, LED and LCD require glass as support, which absorbs some light. OLED, on the other hand, does not need to use glass.
4. OLED does not require a backlight system like LCD. LCD selectively blocks certain backlight areas to display images, while OLED emits light by itself. Due to not needing a backlight system, OLED consumes less power compared to LCD (where most of the power consumption is for the backlight system). This is particularly important for battery-powered devices such as mobile phones.
5. OLED is easier to manufacture and can be made in larger sizes. Being made of plastic material, OLED can be manufactured into large thin sheets. In contrast, it would be much more challenging to use so many crystals and lay them flat.
6. OLED has a wide viewing angle, reaching around 170 degrees. LCD needs to block light when operating, leading to natural viewing obstacles at certain angles. As OLED emits light by itself, the viewing range is also much wider.

0.96 inch I2C IIC Communication 12864 Display OLED LCD Screen Module

1. Voltage: 3V~5V DC
2. Operating Temperature: -30℃~70℃
3. Duty Duty: 1/64 duty
4. High Resolution: 128 64
5. Panel Size: 26.70 19.26 1.85 mm / 1.03 0.76 0.07 inches (approx.)
6. Effective Area: 21.74 11.2 mm / 0.86 0.44 inches (approx.)
7. Driver IC: SSD1306
8. 128 * 64 LED display module, supporting various control chips.
9. Fully compatible with 51 series, MSP430 series, STM32/2, CSR IC, etc.
10. Ultra-low power consumption: 0.08W when the full screen is lit.
11. Super high brightness and adjustable contrast
12. With embedded driver/controller
13. Interface Type: IIC

Two very important points about OLED:

Firstly, the pixel matrix. A pixel matrix, also known as a raster image or pixel map, is a graphic composed of tiny units called pixels, and it may become distorted when resized. The smallest unit in a bitmap is a pixel, and the display effect is achieved by arranging an array of these pixels. Each pixel contains its own color information. When editing a bitmap image, you interact with each individual pixel. You can modify the hue, saturation, and brightness to change how the image appears. To visualize this, think of a bitmap image as a painting on a large sandbox. From a distance, the image looks detailed and colorful. However, up close, you can see each grain of sand that forms the picture, with each grain having a simple, unchangeable color.

OLED is essentially an M x n pixel matrix, where specific pixel positions need to be illuminated in order to display content. For each pixel, it can either be lit up as 1 or not lit up as 0.

The Second: Coordinate System

A coordinate system is a widely used tool in science for providing a reference framework. Common types include the Cartesian coordinate system and the plane rectangular coordinate system. To describe the position, speed, and direction of a particle's movement, a specific coordinate system needs to be selected. In any frame of reference, "coordinates" are the set of ordered data chosen according to a specified method to determine a point's position in space. The process of determining these coordinates for a particular problem is known as the coordinate system used for that issue. Several types of coordinate systems exist, with popular ones being the Cartesian coordinate system, plane polar coordinate system, cylindrical coordinate system, and spherical coordinate system. In high school physics, the rectangular or orthogonal coordinate system is commonly used. More broadly, all abstract concepts of entities exist relative to their respective coordinate systems. An identical object may have different abstract representations depending on the coordinate system used. The number of abstract concepts related to an object expressed by a coordinate system, which corresponds to the number of coordinate axes, defines the dimension of the space where the object exists. Two objects capable of influencing each other must reside within the same coordinate system.

In the OLED coordinate system, the top left corner is the origin, the X-axis extends to the right, and the Y-axis extends downwards.

TAG：OLED LCD Screen Module,Electronics product design,Electronic Conponent

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