Measurement of the characteristics of information display devices (screens, media facades, information boards, etc.) used on city streets, facades of buildings, in internal rooms, railway sta

Description

The massive introduction of information display devices based on self-luminous elements (LEDs, plasma panels, LCDs, etc.) necessitated an adequate assessment of their parameters and quality control of production and installation. The most common among the indicated types of devices are LED screens and boards. The variety of their sizes, color schemes and types of image formation is incalculable.

Despite the fact that one of the first applications of LEDs in lighting devices relates to lighting advertising, their mass introduction as light sources in the field of architectural and artistic, advertising and decorative lighting is actively continuing to this day. The results of significant experience of their use in large information screens and display boards have led to the emergence of a whole industry of production of target LEDs and a significant reduction in the cost of such projects. LED screens, media facades, and dynamic backlight devices have become affordable, economical, and virtually unlimited in control options. However, the obvious drawbacks of lighting systems containing millions of LEDs in one complex (the need to sort by parameters, uneven radiation degradation, significant temperature dependencies) did not lead to the appearance of fundamentally new modifications of such light sources replacing the traditional emitting crystals based on nitrides and gallium phosphides and aluminum . Therefore, the relevance of assessing the parameters of devices based on them and quality control and installation remains extremely high. One of the national standards GOST R 52870-2007 “Means of displaying information for collective use is dedicated to this. Requirements for the visual display of information and methods of measurement ", as well as the well-known joint ventures 52.13330.2016 and SanPiN 2.2.1 / 2.1.1.1278-03, where not only the parameters of the devices themselves are normalized, but their" impact "on the surrounding infrastructure - residential buildings and roads.

In connection with the indicated relevance, the laboratory “Arkhilayt” has developed a measurement program for clients, which may include tests of already assembled devices for compliance with the requirements of the listed standards (as well as any others), and individual elements of these devices (cabinets, modules, LEDs, secondary power supplies, etc.). In addition to this, it is possible to analyze the quality of the nodes produced (from emitting LED crystals to fully mounted devices) at any stage of production, with a trip to the production sites. The latter is most relevant in the preparation and approval of parameters included in the relevant contract for the supply of equipment in order to avoid situations where an expensive screen has already been delivered and its characteristics have not been properly declared by the manufacturer or agreed with the supplier.

In the most general case of measurements of parameters of already installed screens, boards or media facades, their list, as a rule, has the following content.

Brightness of the white field (subject to setting the white balance) and its unevenness (distribution of brightness across the field)

Colorimetric characteristics of the white field (Correlated color temperature)

Brightness of fields of basic colors and its unevenness (distribution of brightness across the field)

Colorimetric characteristics of the base color fields

Average brightness in a dynamic image

Radiation angle (viewing angle) in any plane of the canvas, both under the condition of white balance, and when setting the base colors

Analysis of the parameters and build quality of the device nodes (cabinets, modules, LEDs, secondary power sources, etc.).