Are you designing a device with a screen? It is a step in the right direction. Modern electronic devices are increasingly equipped with displays for aesthetic reasons and, most importantly, functionality. Today, the screen is more than just an element that presents data. It has become a key user interface, enabling intuitive control, instant response to system messages, and direct interaction with device functions.
Table of Contents
In this guide, we present the most important issues to consider when choosing the optimal display for the solution you are designing. These issues almost always arise at the initial stage of cooperation – they help us better understand the needs of the end user and the specifics of the application in which our product is to be used.
Such a “technological interview” is not just a formality – it is the key to effective cooperation, which significantly speeds up the design process and avoids costly mistakes.
In this article, we discuss basic display technologies, parameters such as resolution and brightness, the importance of operating temperature, and the impact of environmental conditions on the display selection.
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Technology
Choosing the right display technology is one of the key design steps. On the Unisystem offer, you can find, e.g., LCD-TFT, OLED, EPD (e-paper), and monochrome (graphic and character) displays. Each differs in construction and functionality, including the way of image presentation, power consumption, or backlighting requirements.
LCD-TFT is currently the most popular and versatile solution. Proven, flexible, and continuously developed, it offers excellent optical parameters and a wide range of diagonals and formats, making it applicable to almost any application. Noteworthy is the local dimming function – local control of backlighting – which improves contrast by allowing inactive areas to be extinguished and those with content to be illuminated simultaneously. It is a way to significantly enhance the image quality without sacrificing the advantages of TFT.
EPD displays are also becoming increasingly popular – especially in battery-powered devices, in which low power consumption is essential.
Resolution
Resolution is a parameter that determines the number of pixels that make up the image on the display. It is expressed as the product of two numbers: the number of pixels horizontally and vertically. For example, a resolution of 1920 × 1080 means that the screen presents 1920 columns and 1080 rows of pixels, giving more than 2 million points that make up the image.
Choosing the optimal resolution depends on the distance between the user and the screen. The higher the pixel density, the greater the detail and comfort of reception. However, you should remember that higher resolution means higher hardware requirements – e.g., for the controller. Therefore, you should look for a balance between image quality and system capabilities.
Learn more about the resolution in our article.
Brightness
The brightness of the display, defined in cd/m² (candelas per square meter), also known as nits, is one of the key parameters affecting the readability of the presented content.
It is worth noting that this parameter refers primarily to LCD-TFT technology, in which the image is formed by passing light from the backlight through a layer of liquid crystals and color filters. The LED backlight system is responsible for the actual brightness of the screen – its power, component quality, and placement directly affect the final visual effect.
Not all information visualization technologies emit light – an example is EPD (e-paper) displays, which reflect ambient light. In their case, instead of “brightness,” we are talking about readability under given lighting conditions.
In the case of LCD-TFTs, the brightness level should depend on the lighting conditions in which the device operates – natural, artificial, intense, or limited lighting.
To illustrate:
- about 250 cd/m² – a level sufficient for home or office conditions,
- about 750 cd/m² – for working in heavily lit interiors,
- at least 1000 cd/m² – outdoor applications*.
*In locations with high sunlight, we recommend using displays with a brightness of at least 2500 cd/m² – such as solutions by Litemax.
Check out our practical guide to better understand how to select the brightness of the display according to the conditions in which it will operate.
Operating temperature range
The environment in which the device will operate – low or high temperatures or perhaps locations with large thermal fluctuations – directly affects the selection of the appropriate display.
On the Unisystem offer, you can find modules with a wide operating temperature range, of which -20°C to +70°C is a standard yet optimal range.
Additional support solutions are commonly used in environments where the device may be exposed to extreme temperature conditions. These solutions can be heating systems (e.g., heaters) at low ambient temperatures or cooling systems (e.g., fans) at high ambient temperatures. They allow the device’s operating parameters to be maintained at a level that ensures its proper operation.
The issue for displays exposed to direct sunlight is the matrix’s resistance to overheating. Extreme temperatures can lead to the transition of liquid crystals from a nematic to an isotropic state, resulting in so-called “black spots” – permanent image disturbances. To prevent this, HiTNI (High TNI) technology, which is based on liquid crystals with a higher phase transition temperature, is used. Thanks to it, the matrix maintains optical stability even when heated intensively, guaranteeing image readability. It is a technology dedicated to applications working in direct sunlight – without the risk of damage due to overheating of the matrix.
Application
One key factor in selecting a display is analyzing the device’s intended use, which allows you to determine the screen’s conditions. Usually, the application defines the operating environment and detailed requirements, directly influencing the selection of suitable technologies, parameters, security, and functionality.
Before deciding on a specific solution, it is worth answering several questions, such as:
- Will the device be used indoors or outdoors?
- Will it be in a public space where it will be exposed to heavy use?
- Will the device be used in extreme temperatures or with rapid temperature changes?
- How bright will the environment in which the screen will be operated be? Or will it be exposed to direct sunlight?
The answers to these questions help narrow down the choice of technologies and design solutions that will ensure reliable performance and a long life for the device. Indicating the application’s intended use is often enough to suggest the optimal configuration.
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