METHOD AND DEVICE FOR CHARACTERISING A TRANSPARENT ENCAPSULATION SCHEME
Publication Date: 2015-Jun-17
The IP.com Prior Art Database
The invention relates to a method for characterizing a transparent encapsulation scheme of a component susceptible to deterioration by water, the method comprising a step of preparing a sample formed of a calcium layer on a surface of a transparent substrate within the encapsulation scheme, the calcium layer having an initial amount of calcium; a plurality of measuring steps in successive instants, each measuring step comprising acquiring an image of a light radiation transmitted through the sample and the processing of the image to estimate the residual amount of calcium in the sample at each of these instants; a step of selecting images corresponding to an estimated amount of residual calcium strictly between 40% and 100% of the original quantity to determine a sequence of pictures ordered; a step of determining a characteristic permeation water encapsulation scheme from the sequence of pictures ordered.
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METHOD AND DEVICE FOR CHARACTERISING A TRANSPARENT
FIELD OF THE INVENTION
The invention concerns a method and device for
characterising a transparent encapsulation scheme for a
component liable to be damaged by water.
TECHNOLOGICAL BACKGROUND TO THE INVENTION
Certain components are liable to be corroded by moisture.
This is in particular the case with organic electronic
components, which may find their applications in the field of
the production of photovoltaic energy.
It is then usual, as illustrated in the document entiteled
« Material challenge for flexible organic devices », Jay lewis,
Volume 9, Issue 4, April 2006, Pages 38-45, to protect the
component from its environment by encapsulating it in a
Figure 1 depicts a known configuration or flexible
encapsulation of such a component, comprising two barrier films
B, positioned on either side of a component D, and an adhesive
A for holding the barrier films on the component and
material or a combination of materials forming a barrier to the
diffusion of water and oxygen, the main gases involved in the
degradation processes. For applications in the photovoltaic
field and more generally in the optoelectronic field, these
materials must be transparent. 25
encapsulating it laterally. In general terms, all the elements
deployed for isolating the component from the oxygen and water
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present in the environment, generally in the form of vapour,
are referred to as an "encapsulation scheme".
The choice of an encapsulation scheme suited to a given
component or application is an important step in the complete
design of an applicative system.
To guide this choice, a technique for evaluating a lateral
encapsulation material is known from the document "Evaluation
and modelling of edge seal material for photovoltaic
application" by M.D Kempe, IEEE Photovoltaic Specialists
Conference, June 2010. This technique consists of depositing a
thin layer of calcium on a glass substrate, laminating the
whole on a second glass substrate, and protecting the edges of
this assembly from the lateral penetration of water by means of
an encapsulator to be characterised.
Calcium, opaque in its metallic form, reacts very strongly
with water in order to form a transparent hydroxide:
Ca + 2H2O -> Ca(OH)2 + H2
According to the document cited, observing the
transformation of the peripheral edges of the thin layer of
calcium into a transparent material makes it possible to easily
determine the lateral penetration distance of water, and more
generally the characteristic of the encapsulator with regard to
the permeation to water.
The technique disclosed in this document is however 30
limited to the evaluation of the lateral permeation of an
encapsulating material in combination with glass. This
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technique is not suitable when the encapsulation scheme is
flexible and composed of two barrier films placed by means of
an adhesive on either side of the component, as depicted...