Steps and precautions for frame bonding touch panel
Date:2025-05-14
Detailed steps and precautions for Frame Bonding Touch Panel, suitable for production or maintenance scenarios of industrial, medical, or consumer electronic devices:
I．Steps for frame pasting touch screen
1. Preparation work
-Tools and materials:
-Touch screen module (capacitive/resistive), display screen module (LCD/OLED), OCA optical adhesive (or double-sided adhesive), UV curing adhesive, cleaning agent (isopropanol/IPA), dust-free cloth, UV curing lamp, alignment fixture, pressing equipment.
-Environmental requirements: Clean room (recommended cleanliness level ≤ 1000), temperature and humidity control (temperature 20-25 ° C, humidity 40-60%).
2. Clean the surface
Screen cleaning:
Use a dust-free cloth dipped in isopropyl alcohol (IPA) to wipe the surface of the display screen, remove oil and dust, and ensure that there are no residual fibers or particles.
-Touch screen cleaning:
Clean the inner surface (bonding surface) of the touch screen using the same method to avoid fingerprints or dust affecting the bonding effect.
3. Alignment calibration
-Using alignment fixtures:
Fix the display screen on the fixture, position the touch screen through vacuum suction or mechanical fixture, and adjust the X/Y/θ axis to align the touch screen with the edge of the display screen.
-Optical alignment verification:
Turn on the backlight of the display screen and check the alignment accuracy through a microscope or CCD camera (usually with an error of ≤ 0.1mm).
4. Coating and bonding
OCA optical adhesive bonding:
-Tear off the OCA adhesive protective film, and use a roller or vacuum suction to lay the adhesive film flat on the touch screen bonding surface to avoid bubbles.
-Gradually press the air from the center to the edges using a compression device (Roller or Vacuum Laminator).
-Double sided adhesive bonding (low-cost solution):
Cut the double-sided tape into a frame shape, attach it along the edge of the touch screen, and manually press to remove bubbles.
5. Curing treatment
-UV curing (applicable to OCA adhesive):
Use a UV lamp (wavelength 365nm, intensity ≥ 50mW/cm ²) to irradiate the adhesive layer for 10-30 seconds to ensure complete curing of the adhesive.
-Natural curing (partially double-sided adhesive):
Let it stand for 24 hours to avoid external interference.
6. Functional testing
-Touch sensitivity test:
Use standard testing software (such as Touchstone) to detect touch linearity and multi touch response.
-Optical inspection:
Turn on the display screen and check for Newton rings, rainbow patterns, or bubbles.
-Environmental reliability testing (optional):
Conduct high temperature and high humidity (85 ° C/85% RH, 48 hours), cold and hot shock (-40 ° C~85 ° C, 5 cycles) tests.
II、 Precautions
1. Environmental control
-Dust free environment: Dust can cause white spots or bubbles to appear after bonding. It is recommended to operate in a dust-free table or clean room.
-Stable temperature and humidity: Excessive humidity can cause abnormal curing of the adhesive, and temperature fluctuations may cause material deformation.
2. Adhesive selection
-OCA adhesive: high transparency (≥ 92%), but high cost, requiring precise control of adhesive thickness (such as 50-200 μ m).
-Double sided tape: Low cost, but prone to edge warping, suitable for bonding in low-end or non transparent areas.
-UV glue: cures quickly, but excessive exposure to ultraviolet rays should be avoided to damage the polarizing film of the display screen.
3. Avoid common problems
-Bubble exclusion:
-When pressing, use slow rolling (speed ≤ 5mm/s).
-If bubbles are found, they can be filled with a small amount of glue injected with a needle and re pressed.
-Edge overflow glue:
The amount of glue used should be precisely controlled, and any excess glue should be wiped with a dust-free cloth dipped in IPA before curing.
-Newton's ring (interference pattern):
Choose non-conductive OCA adhesive or adjust the bonding pressure (usually ≤ 0.5MPa).
4. Equipment calibration
-Regularly verify the alignment accuracy: calibrate the fixture with a standard test board every week to prevent mechanical deviation.
-Compression pressure control: Excessive pressure may cause glass breakage (recommended ≤ 0.3MPa).
5. Safety and Maintenance
-UV protection: Operators need to wear UV protective goggles to avoid direct skin contact with glue.
-Equipment maintenance: Regularly clean the pressing roller and vacuum adsorption platform to prevent glue residue.
III.Common Problems and Solutions
Frequently Questions | Reason | Solution |
Bubbles after bonding | Dust residue or excessive pressing speed | Rework, clean and reduce the pressing speed |
Touch malfunction | Alignment offset or excessively thick adhesive layer | Reposition and adjust the adhesive thickness |
Edge warping | Insufficient adhesion or large temperature difference of double-sided tape | Replace high viscosity adhesive and control environmental temperature and humidity |
Rainbow pattern | OCA adhesive interferes with polarizing film | Use anti Newton ring adhesive or adjust the integration angle |
4、 Summary
The core of a framed touch screen lies in precise alignment, dust-free operation, and adhesive process control. In industrial applications, it is recommended to prioritize the use of OCA optical adhesive and UV curing solutions to ensure transparency and reliability; Consumer electronics can balance cost and performance by using double-sided tape. After bonding, strict optical and functional testing is required to avoid batch defects.
G190ETN01.4：https://www.auo-lcd.com/products/auo-lcd-screen/19inch/g190etn01.4.html
Touch screen：https://www.auo-lcd.com/products/auo-lcd-screen/
