LED Display Contrast

Along with proper brightness, a display must have high contrast for good readability. Contrast is the difference between the background’s “off state” (blank display area) versus the “on state” (illuminated display area). High contrast increases the readability of a message, much like white text on a black background, causing readers to focus on what needs to be seen. The highest contrast appears in a display with a dark border and a consistent dark black background across the entire display with minimal sunlight reflection. A louver system provides shading and black, non-reflective materials ensure the least amount of reflection. Polycarbonate or acrylic face material may provide as high a contrast as flat black paint or a black potting encapsulant.

What is Grey Level?

Grey level: A calibrated sequence of grey tones, ranging from black to white. In remote sensing, electromagnetic radiation falling on a photosensitive receiver generates an electrical current proportional to the intensity of the radiation. The receiver is usually tuned to specific wavelength bands and the signal from each receiver is amplified and its intensity classified into different levels, usually 0 (black) to 256. These are the digital numbers of each of the pixel units that together make up a remotely sensed frame. In multi-spectral scanning systems, the digital numbers are classified into grey-scale bands, of which there are usually 10 to 12, but up to 256 shades of grey (brightness) may be used.

The Explanation of Ingress Protection (e.g.IP65)

Ingress Protection (IP) is a European rating that describes the degree of protection provided by an enclosure of electrical equipment. The rating system consists of the letters IP followed by two numbers:

The first number indicates the degree of protection against solid foreign object ingress.

The second number indicates the degree of protection against liquid ingress.

According to this system an IP65 enclosure will not allow the ingress of dust and is protected against jets of water from any direction. IP65 enclosures are ideal therefore for use in wet and wash-down environments for example food preparation areas.

What is Maintenance of LED Display

LED Display is commonly seen nowadays. When speaking of maintennace of LED screen, we usually refer to the front and rear maintenance method.

Front Maintenance

One distinctive character of front maintenance is it’s being space-saving. For most indoor LED display and inlaying-installed LED displays, saving space means everything. And front maintenance type screen has a ultra slim structure. This type of display usually has very high requirement in heat dissipation ability.

Rear maintenance

LED Display produced by Chinese manufacturers are usually designed with back doors. That is what we called rear maintenance type. Rear maintenance is convenient to outdoor spectaculars and some other installations. Usually there will be a back-end passage for technicians to check and fix the LED display

LED Display Lifetime

The operational lifetime of an LED Display is determined by the lifetime of the LEDs. LED Manufacturers estimate the LED lifetime to be 100,000 hours under certain operating conditions. LED Display end of lifetimes is when the frontal brightness has decreated to 50% of original brightness.

Three primary factors determine LED lifetime:
Manufacturing process of the LED
Driving (powering) method of the LED
Temperatures present at the LED die during operation

LED thermal management is vitally important to maintaining LED lifetime. Increasing the power through an LED increases brightness but reduces its lifetime due to increased heat generation. Increased exposure to higher temperature also shortens the lifetime. LED thermal managerment can only be done through the LED lead frame by conducting the heat to a Printed Circuit Board (PCB) and by allowing allowing airflow to cool the LED lead frame.

LED Display components must be designed to handle a wide rang of outdoor environmental factors, such as temperature and humidity. All components must be coated to protect from possible corrosion.