Scope of application
Capacitive multi-touch screens suitable for consumer electronics (such as MID, car DVD, etc.).
Features and General Specifications
Structure and Materials
The structure of the touch screen is shown in Figure 1, the materials are shown in Table 1, and the engineering structure diagram is shown in the attachment.
Figure 1 The structure of the touch screen
Note: The calculation method of average transmittance is:
Tavg = Σ(Ti)/401, i is the wavelength (from 380 to 780)
Note: The calculation method of average transmittance is as following:
Tavg = Σ（Ti)/ 401, i is wavelength (from 380 to 780)
Table 1 The structure and materials of the touch screen
Structure | Materials used | Comment |
Panel layer | PET | Thickness: 0.25 mm |
Bonding layer | Optical transparent glue（OCA） | Thickness: 0.125 mm |
Induction circuit layer (ITO glass) | ITO GLASS | Thickness: 1.10 mm |
Lead wire | FPC | Thickness: 1.2(max)mm |
Driver IC | GT928 | Package：8×8×0.43 |
Test requirements
Before the touch screen is shipped, it needs to meet the requirements of electrical performance testing, environmental parameters, mechanical performance testing, optical characteristics, and ESD. Their test requirements are as follows.
Electrical performance
Project | Value |
Operating Voltage | DC2.8V~3.3V |
Insulation resistance | ＞20MΩ or over (DC=25V) |
Working current | 5mA～20mA |
Response time | ≤16ms |
Environmental parameters
Project | Standard | Value |
Range of working temperature | 1.Features OK 2.Exterior OK | -20℃～+70℃ |
Storage temperature range | -30℃～+80℃ |
Mechanical behavior
Project | Description |
Finger contact area | φ≥5MM |
Optical properties | >85.00 % |
Surface hardness | 3H |
The transmittance test method and transmittance of the touch screen are shown in Figure 5.
Figure 5 Transmittance and test method of touch screen
