LCD Screen Explosion Test: How to Select the IK Rating
LCD Screen Explosion Test: How to Select the IK Rating
We often hear statements like "This product reaches IK10 level" or "It must meet the IK08 protection requirements". But how are the IK levels defined? How is the corresponding impact resistance capability quantified? And how should the tests be conducted? In this article today, by combining international standards and industry practices, we will systematically break down this core protection indicator for you.
1. Why are there IK fall levels? (The emergence and development of IK levels)
The emergence of the IK rating is essentially a necessary demand for "quantitative protection" in industrial development. In the mid-to-late 20th century, as electrical equipment moved from laboratories to factory workshops and public spaces, equipment failures caused by accidental impacts occurred frequently.
However, at that time, the industry's description of "impact resistance" was entirely subjective. Vague terms such as "robust and durable" and "impact-resistant" left manufacturers, purchasers, and users in a state of information disconnection.
The following key events have driven the progress of the entire industry through the pressure of safety and responsibility:
The 2005 European subway signal equipment failure incident
In the winter of that year, a certain subway line in Germany suffered from damage to the outer casing of the signal control cabinet due to being hit by cleaning tools. This led to moisture in the internal components causing a short circuit, resulting in a complete line shutdown for 4 hours. After the investigation, it was found that the "impact prevention" description used for this control cabinet had no quantitative basis. Its actual protective capability could only withstand 0.3J of impact, which was far below the 2J requirement for the subway environment. This incident directly prompted the revision of the IEC 62262 standard in 2009, adding IK07 (2J) and IK08 (5J) among others as medium-level ratings, and clearly defining the minimum protection requirements for public transportation equipment.
2. Safety Accident of Outdoor Charging Stations in Southeast Asia in 2012
In the early stage of promoting electric vehicles in a certain country in Southeast Asia, multiple outdoor charging stations suffered cracks in their shells due to being hit by branches after heavy rain, allowing water to seep in and causing an electric leakage accident, resulting in two injuries. After testing, although these charging station shells were marked as "impact-resistant", they did not meet the IK standard and the impact energy tolerance was less than 1J. This incident prompted the IEC 62262 to revise in 2014, strengthening the impact test requirements for outdoor equipment, clearly defining IK10 (20J) as the recommended protection level for outdoor electrical equipment, and standardizing the temperature and humidity conditions of the testing environment.
3. The 2018 Outage of Consumer Electronics After-sales Disputes
A well-known mobile phone brand faced a large-scale after-sales complaint due to the "drop-induced screen breakage" issue. Consumers questioned the difference between the product's impact resistance performance and the advertised claims. A third-party testing institution, following the IEC 62262 standard, found that the phone's casing could only withstand 1J of impact (corresponding to the IK06 level), yet it claimed to be "impact-resistant". This dispute led the consumer electronics industry to reach a consensus: clear labeling of the IK level and corresponding impact energy must be provided, forcing mobile phones, tablets, and other products to take IK06-IK08 as the basic protection indicators.
Since then, the IK rating standards have undergone multiple iterations and improvements:
In 2009, multiple higher-level protective grades were added, filling the gap in the protective needs of industrial equipment.
In 2014, a more precise impact testing method was introduced to reduce testing errors.
In 2021, the 1.1 version of the consolidated version was released, integrating the contents of the original edition and all previous revisions, making the standard more unified and operable.
Nowadays, IEC 62262 has become the core standard for shock protection of electrical equipment worldwide. Regional standards such as China's GB/T 20138 and Europe's EN 62262 are all equivalent in technical content to it.
II. Correspondence between IK Rating and Joule Value
IK rating = The mechanical impact energy (J) that the housing or display screen can withstand under the specified test conditions.
It is not a matter of "throwing it around casually", but rather involves strictly controlling the following variables:
Impact body mass - Impact speed / Drop height - Impact point position - Number of impacts
Basic physical formula: Impact energy E = m × g × h
Among them:
E: Impact energy (J)
m: Mass of the impacting body (kg)
g: Gravitational acceleration (≈ 9.81 m/s²)
h: Drop height (m)
Take IK10 (20 J) as an example. If a 5 kg impactor is used:
h ≈ 20 ÷ (5 × 9.81) ≈ 0.41 m
That is to say: > A 5 kg impact object, freely falling from a height of 40 cm, generates approximately 20 J of impact energy.
