Electronic and Electrical EquipmentTouch panel

High-precision dam application and fill application of UV resin in the touch panel attachment process

Existing issues

To attach smartphone touch panels, the customer applies UV resin on the surface via a "dam application," in which adhesive is applied in a line to the outer perimeter of the touch panel, and a "fill application," in which UV resin is applied and spread inside the perimeter of the "dam". The existing application equipment used for these techniques had the following issues:

  1. Discharge volumes were unstable, with variable line widths.
  2. The starting point and end point of application could not be made into a clean joint.
  3. The inconsistent application amount could cause bubbles to be trapped between the attached surfaces or the adhesive to extend beyond the perimeter.
  4. If viscosity changed with the temperature change in the fluid, discharge efficiency was seriously affected to the point that it required time-consuming readjustment.

Solution

Heishin Dispenser HD, which offers precision small-capacity application of high-viscosity fluids while being resistant to changes in viscosity, was adopted.

Benefits from the improvement

  • The problem of variable line widths is resolved and the joint of application starting point and end point is clean, both of which contribute to improved quality.
  • Bubbles are no longer trapped and adhesive no longer sticks out, which improves yield.
  • The number of adjustments necessary is significantly reduced, which has in turn reduced the burden on the operator and the loss of materials.

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