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The thickness of glue height measurement

Date:2020-06-04 Source:Samsun Technology

   Glue height and thickness measurement for cut-out screen camera module installation   


For a more extreme visual experience, after bangs, full-screen, sliding screen and double-sided screen, the hole-dig screen is also here. The hollow of the perforated screen is divided into two processes: through-hole and blind hole. Through-hole is a hole in the screen, which is more beneficial to the imaging of the front camera, after all, there is less of a barrier, but the process is relatively more complex, the quality control requirements are more stringent, the yield rate is lower, there is also a problem is the hole diameter is larger, generally in 6.5mm above. Blind hole is to put the camera under the screen, the process is relatively more mature, high yield and low cost, small aperture, but because of the extra layer of liquid crystal, will inevitably affect the light transmission rate, the image quality of the camera will also have a certain impact.
 
 
     The thickness of glue height measurement_heydanbo.com

For a more extreme visual experience, after bangs, full-screen, sliding screen and double-sided screen, the hole-dig screen is also here. The hollow of the perforated screen is divided into two processes: through-hole and blind hole. Through-hole is a hole punched in the screen, for the front camera "through-hole" can effectively reduce the screen layer on the front camera blocking, so in the photo to get more advantageous when the light. This process requires a high level of glue dispensing and if the glue height is not consistent, the final screen image will have gaps and unnatural articulation. The use of spectral confocal sensors can be a good solution to this problem, not only can the complete measurement of the height of the glue, but also to measure the width, high-speed sampling frequency, more suitable for automated equipment online.
 
    The thickness of glue height measurement_heydanbo.com

However, there is a problem in that the 'through-hole' is much less visually integrated. Because there is no need to take into account the effect of the screen on the camera, a 'through-hole' will have a larger hole in the screen than the camera itself, i.e. a larger hole than the 'blind hole' hidden underneath the screen.

If ordinary laser displacement sensors are used, the following measurement pain points will exist.
 
The transparent colour of the glue makes it easy for monochromatic light to penetrate directly or to fail to pick up reflected light.

The dispensing is curved and the reflected light cannot be picked up by ordinary laser sensors.

The narrow opening of the perforated screen makes it impossible for spectral line scan or other surface array sources to measure.

    The thickness of glue height measurement_heydanbo.com

Digging hole screen camera module installation, due to the glue used for dispensing is transparent glue, this glue detection has two difficulties, one is that after dispensing, the shape of the glue is curved, this is very test light pen mirror reflection angle, if the use of monochrome laser sensor detection, will cause the light to hit through, the laser directly penetrate to the bottom of the glue, or because of the reflection angle caused by the curved reason, can not reflect light back.

 
The thickness of glue height measurement_heydanbo.com

This is why it is now common practice in the industry to use a large angle spectral confocal sensor. As the spectral confocal sensor uses white light, which is a composite light, there is always light that can be reflected back, and for the curved surface, the reflection angle of the light pen is increased (45°), so that the outline of the white transparent dotted glue can be measured perfectly.

The thickness of glue height measurement_heydanbo.com

Glue height 0.163mm, angle 40.3°, radius 0.327mm


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