What is OCA Bonding Technology?

There are many ways to fix the layers of a display together, one of is OCA bonding, or optically clear adhesive (OCA) bonding, which attaches display layers together with a sheet adhesive.

OCA

Classification and Structure 

OCA-Structure
Figure 1. OCA Structure
  • Used for bonding the upper and lower sensors of the touch screen, the thickness is 25μm or 50μm, usually rolled material;
  • Used for bonding the touch screen cover and the sensor, the thicknesses of 75μm, 100μm, and 125μm, usually in sheet form;
  • Used for bonding the touch screen or cover to the display module, the thickness is 100μm, 150μm, or 175μm, usually in sheet form.
OCA typeCan be Produced Thickness
Weak acid OCA25~500μm
Weak base OCA25~50μm
Heat cured thin OCA10~50μm
UV cured thick OCA50~500μm
Organosilicon OCA10~150μm
Double sided anisotropic OCA50~200μm
UV barrier OCA10~50μm
Table 1. The thickness that can be produced of various OCA adhesives

Choose of OCA

OCA Bonding Process

OCA Bonding Process 1
Figure 2. OCA Bonding Process

Advantages of OCA Performance

Disadvantages of OCA Process

Application

OCA, OCR and OCF

OCA vs. OCR vs. OCF

Compare itemOCAOCR (LOCA)OCF
Interval controlDepends on OCA thickness and accuracyhard to controlCan be precisely controlled
Glue overflowNoYesNo
AdhesionWeakerStrongerGenerally
Repair step differenceThere are bubblesDiffcult to produce bubbles for point touchAbility better than OCA
Segmental AbsorptionGenerallyGoodBetter
EfficiencyGenerallyGenerallyThe same equipment can be used for batch and continuous production
Bonded product yieldThe one-time yield is over than 90% and can be repairedThe first-time yield is less than 90%, making it difficult to repairThe one-time yield is over than 95% and can be repaired
Equipment investmentGenerallyHigherGenerally
Material requirementsNo special requirementsHard to hard material fitNo special security requirements
ApplicationSmall size productSmall and medium size productsVarious sizes of product
Table 2. OCA vs. OCR vs. OCF

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