What is OLED Display? OLED stands for organic light emitting diode. Its name shows that it is flat light emitting technology which is developed when two organic thin films are connected in series between two electric conductors. When electric current is supplied to these conductors then organic compound is made which emits the bright light. Typically, one conductor is the transparent conductor between these two conductors therefore there is no need to any back light to emits the light. Therefore, this OLED display has improved image quality, full viewing angle, high brightness, better contrast, wide color range, low power consumption, more efficient and reliable as compared to simple LCD display. It is mainly used in digital display devices such as computer monitors, mobile phones, hand held games and televisions screens etc. These are easily available in market as well as on online shops. A simple OLED display is shown in figure 1
Figure 1 A Simple OLED Display
Pin Configuration of OLED Display
Every OLED display consists of seven pins which are used for different purposes. First one is GND pin which is connected with source ground for suppling ground to this display, second one is VCC pin which is connected with source VCC for suppling +5V to this display. Third one is SCK pin which is used as a lock pin or used for both 12C and SPI. Fourth one is SDA pin which is used as a data pin for module. Fifth one is RES pin means reset pin which is used for resetting to this OLED display. Sixth one is DC pin means data command pin and is used for SPI protocol. Similarly, the last one or seventh one is CS pin means chip select pin and is used when one or more modules are used under SPI protocol. The pin configuration figure of this OLED display module is shown in figure 2
Figure 2 Pin Configuration of OLED Display Module
Working Principle of OLED Display
The working principle of this OLED display is very simple. This LED display consists of organic material layers which are situated between two electrodes that are called anode and cathode. When these electrodes are connected to dc supply then current is passed through these electrodes then electrons are deposited on electrode substrate. Basically, organic material is made of semiconductor material whose electrical properties are in between conductor and semi-conductor. Therefore, when current is supplied to their electrodes then the electrons which are deposited at electrode substrate, delocalize the organic molecule.
During this delocalization the electron of organic molecule moves from valance band to conduction band. Similarly, the light is produce in this organic material layer. The most simple and basic OLED display consists of a single organic layer whose example is first light emitting device which was synthesized by J.H. For improving the efficiency of LED display device multilayer LED display could be made with the help of two or more layers of organic material. Similarly, for improving the conduction properties different material could be aid in electrode material.
How to Interface OLED Display with Arduino Board?
Any microcontroller or board is must require for using this OLED display, for display purpose. So different people use different controller but here we shell the user how interface this display with Arduino board. First of all, one thing should be keep in mind some of displays has swapped ground (GND) and VCC pin therefore the user should be make sure before connecting the OLED display with Arduino board. The interfacing connection of Arduino board with OLED display is shown in figure 3
Figure 3 The Interfacing Connection of Arduino Board with OLED Display
According to figure 3, because it is operated at 3.3 or 5 volts dc therefore it is directly powered up with Arduino board and for this GND and VCC pin of display is connected to Arduino board VCC and GND pin. Similarly, SCL and SDA pin of this display is connected to Arduino board A5 and A4 pin. After this, the program is upload in Arduino board using Arduino library with the help of Arduino IDE software. Suppose we want to display “hello word” then program is upload after writing this word.