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UV-Bonding Measurements

Analysis of UV cured Optical Bonds and Methods for Volume Testing

- New principles for high-speed testing -

How to measure improper optical bonds?color dispersion across all viewing angles

There are several „classical“ methods – but then you have destruction.

But there are some – trial – methods for NON destruction.

To name two of them:

    • color dispersion across all viewing angles ... and a bit simpler 
    • 4-side spectral measurement ... beside other

All have the problem to be „integral“ judging the complete behaviour of theuv bonding 02 02bonded display head – not the bond ONLY.

And on top: how to then select the UV-driven problems out of it?

→ But there is a selective method!

Examples for optical appearance of improper UV-bonding

uv bonding 03 01  uv bonding 03 02   uv bonding 03 03 uv bonding 03 04 
 uv bonding 03 05  uv bonding 03 06  uv bonding 03 07  uv bonding 03 08

Major root-cause of UV-bonding problems: Ongoing exchange of UV-sources for UV-bonding

 uv bonding 04 01

Differences in severeness of UV bonding issues - 1

Selective analyzing optical bonds made by UV-resin
All samples shown are real products – failing at end-customer in field use analysed by our new method

WITHOUT any destruction or delamination of device
WITHOUT  interference of integrated display 
WITH very high sensitivity
VERY QUICK, time requirement for data aquisition  starting at approx. 500ms

 uv bonding 05 01

Differences in severeness of UV bonding issues - 2

Selective analyzing optical bonds made by UV-resin
Samples from different customers using different kind of UV resins – selected for similar size/shape only to better compare

USEFULL for any size - so far used from below 1" to 86"
VERY selective - also for issuses beside UV-bonding problems 

 uv bonding 06 01

New analysis method from Wammes & Partner provides:

  • A NON-destructive approachuv bonding 07 01
  • A strict focus of the bonding layer only
  • High sensitivity
  • Short testing time
  • Applicability to a broad size range
  • Wide range of detailing from microscopic to macroscopic
  • Usability also for issues apart from UV-resin based bonding
  • And... 

Very high confidence level of results


The detected critical pattern have been very detailed analysed by „classical“ methods using delamination, cryo technics (not to loose any VOCs), gas chromatography, mass spectrometer , TGA, FTIR-ATR and other


Finally very well corelated to the computed results of our new quick and NON-destructive method.

So far we have proven our new method at more than 2000 tested units back from field.

uv bonding 08 02 

uv bonding 08 01

How we do - some insights


Measuring optically clear structures give a quite small signal to noise ratio, so

  • it will be very hard to rank any signal for its amplitude
  • it will be very hard to find stable pattern

We use the „Pattern-Approach“, which is fostered by powerful mathematical algorithms to help us.

Even if we sometimes also get very easy understandable RAW data like the upper picture, we normally need for „every shot“ powerful computing to dismantle the interesting information from the noise.


uv bonding 09 01 

uv bonding 09 02

ONE shot delivers different information

Today we already sort and understand more than 10 ! dedicated „critical“ patternuv bonding 10 01

And every pattern is very selective for its own and very dedicated purpose

Some examples (highlighted in colors):

RED – we call „Placks“ - selective for UV-bonding issues
GREEN – we call „Spätzle“ (german type of noodle) - selective for polymerisation issues
BLUE – we call „Sandpaper“ - selective for surface activation/surface energy issues

Application pictures of improper optical bonding

uv bonding 11 01  uv bonding 11 02   uv bonding 11 03
 uv bonding 11 04  uv bonding 11 05  uv bonding 11 06

Our approach to the market

  1. we already offer such UV-bonding analysis as a service (beside lots of other technical services)
  2. we seek for partners (licensees, measurement equipment companies,…)
  3. for parties interested in IP and service we offer dedicated (Teams-)meetings and webinars. Please feel free to contact us.



Wammes & Partner GmbH
An der Weidenmühle 2
D-67598 Gundersheim

Tel. +49 (0) 6244 / 9197-100
Fax +49 (0) 6244 / 9197-111 


Patents: to overview


i-sft global-lightz


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