Touchscreen hardness testing is a critical quality control step to ensure durability and reliability, especially pre-shipment testing, which can effectively reduce post-sales issues. Here is a detailed introduction:
1. Touchscreen Hardness Testing Methods
(1) Pencil Hardness Test (Common Standard)
Method: Use pencils of specific hardness (e.g., 9H, 8H, etc.) to scratch the screen surface at a fixed angle (typically 45°), observing whether any scratches appear.
Standard: Passing the highest hardness grade (e.g., Mohs hardness 6-7 or pencil hardness 9H) is considered合格.
Equipment: Pencil hardness tester, optical microscope (to inspect scratches).
(2) Mohs Hardness Test
Use minerals of varying hardness (e.g., quartz, topaz) to scratch the screen and assess its scratch resistance.
Consumer electronics touchscreens typically need to achieve a Mohs hardness of 6 or higher (to withstand daily scratches from keys and sand).
(3) Ball Drop Impact Test
Drop a steel ball from a certain height onto the screen to test its impact resistance (simulating a phone drop scenario).
(4) Friction Test (Taber Test)
Apply pressure and friction to the screen using a rotating abrasive wheel to simulate long-term wear and tear.
2. Reasons for Conducting Hardness Tests Before Shipment
(1) Ensure Durability
Touchscreens must resist scratches from daily use (e.g., keys, fingernails, sand), and hardness tests directly verify their resistance to damage.
(2) Reduce post-sales costs
Identify batches with insufficient hardness in advance to avoid returns or repairs due to easily scratched or cracked screens, thereby protecting brand reputation.
(3) Meet industry standards
Customers (such as smartphone manufacturers) typically require compliance with specific standards (e.g., Corning Gorilla Glass hardness certification), and test reports are mandatory delivery documents.
(4) Verify Processes and Materials
The quality of coatings and the stability of glass strengthening processes (such as chemical tempering) must be verified through hardness testing. For example, glass that has not been sufficiently tempered will exhibit a significant decrease in hardness.
3. Industry Application Examples
Smartphones: Typically require pencil hardness ≥9H and Mohs hardness ≥6.
In-vehicle touchscreens: Must pass more stringent friction and impact tests (due to complex environments such as vibration and temperature differences).
Industrial equipment: May require higher grades for explosion-proof or scratch-resistant applications (e.g., sapphire glass).
By conducting hardness tests prior to shipment, manufacturers can effectively control product quality, reduce user complaints caused by screen damage, and meet the stringent reliability requirements of the supply chain.