Method for measuring a permeation rate, a test and an apparatus for measuring and testing

• US 20020152800A1
• Filed: 03/26/2002
• Published: 10/24/2002
• Est. Priority Date: 03/29/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Nisato, Giovanni, Slikkerveer, Peter Jan, Van Der Sluis, Paul, Haskal, Eliav Itzhak, Bouten, Petrus Cornelis Paulus, Van Tongeren, Henricus Franciscus Johannus Jacobus
• Granted Patent: US 6,993,956 B2
• Time in Patent Office: Days
• US Class Current: 73/38
• CPC Class Codes: G01N 15/082 Investigating permeability by forcing a fluid through a sample
• CPC Class Codes: G01N 15/132 Circuits
• CPC Class Codes: G01N 2015/086 of films, membranes or pellicules

Abstract

A method is proposed for measuring water permeability of substrates (1). A reactive compound (Ca, Ba) which reacts with a diffusing material, e.g. water, is applied on the substrate and the change in time of transmissivity, reflectivity of the layer is monitored in time.

Claims

1. A method for measuring the permeation rate of a substrate comprising the steps of

a) applying a layer of a reactive material to a first side of the substrate in an substantially inert atmosphere

b) positioning said first side of the substrate within a substantially hermetically sealed environment

c) exposing the other side of the substrate to an environment containing compounds which react with the reactive material and

d) comparing the light reflectivity or the light absorption of the layer of reactive material with a calibration value.

3. A method according to claim 1 or 2 in which the other side of the substrate is exposed to a controlled environment.

4. A method according to claim 1 or 2 in which the reactive material belongs to the group containing calcium, barium natrium and gadolinium.

5. A method according to claim 1 or 2 in which the compounds which react with the reactive material belong to the group of water and, oxygen and hydrogen.

6. A method according to claim 1 or 2 in which the transmission or reflection value of at least part of the layer of reactive material is determined.

7. A method according to claim 6 in which the transmission or reflection value is related to the amount of remaining reactive material.

8. A method for testing a set of substrates from a batch on permeability which method comprises the steps of

a) measuring the permeation rate of at least on sample substrate with a method according to claim 1 or 2

b) discriminating between batches to have them pass or not pass the test based on a threshold value of the permeation rate.

9. A method according to claim 8 in which the threshold value is determined as either a mean value or an extreme value of the permeation rates within a batch.

10. A method according to claim 8 in which the threshold value is at most 10⁻

4 g/m²/day for water.

11. A method according to claim 10 in which the threshold value is at most 10⁻

5 g/m²/day for water.

12. A method according to claim 1 or 2 in which the hermetic seal comprises At least two walls.

13. A method according to claim 12 in which a getter is provided in the seal.

14. A method according to claim 12 in which the seal comprises the reactive material.

15. An apparatus for a method according to claim 1 or 2 or 8 comprising

a) a first chamber in which an substantially inert atmosphere can be generated

b) means for introducing a reactive material into said chamber

c) means for positioning said first side of the substrate within a substantially hermetically sealed environment

d) means for exposing the hermetically sealed environment to compounds which react with the reactive material

e) means for comparing the light reflectivity or the light absorption of the reactive material with a calibration value.

16. An apparatus according to claim 15 comprising

a first sub-apparatus comprising

a) a first chamber in which an substantially inert atmosphere can be generated

b) means for introducing a reactive material into said chamber

c) means for positioning said first side of the substrate within a substantially hermetically sealed environment

a second sub-apparatus comprising means for exposing the hermetically sealed environment to compounds which react with the reactive material

a third sub-apparatus comprising means for comparing the light reflectivity or the light absorption of the reactive material with a calibration value.

17. An apparatus according to claim 15 in which at least two sub-apparatuses have been combined

18. An apparatus according to claim 15 which comprises external manipulating means.

19. An apparatus according to claim 15 in which the means for exposing the substantially hermetically sealed environment to the second chamber comprise a closed connection between the first and second chamber which connection may be opened to start testing.

20. An apparatus according to claim 15 in which the means for comparing the light reflectivity or the light absorption with a calibration value comprise at least a digital camera.

21. An apparatus according to claim 15 in which the means for comparing the light reflectivity or the light absorption with a calibration value comprise means for obtaining a reflectionspectrum or an absorption spectrum.

22. An apparatus according to claim 13 or 14 in which the means for comparing the light reflectivity or the light absorption with a calibration value further comprise image processing means.

2. A method for measuring the permeation rate of a substrate comprising the steps of

a) positioning a substrate within a substantially hermetically sealed environment

b) applying reactive material to a first side of the substrate in an substantially inert atmosphere

c) exposing the other side of the substrate to an environment containing compounds which react with the reactive material and

d) comparing the light reflectivity or the light absorption of the layer of reactive material with a calibration value.

23. A method for measuring the permeation rate of an encapsulation comprising the steps of

a) applying a layer of a reactive material to a first side of a substrate or to the encapsulation

b) fixing said encapsulation to the first side of the substrate in a substantially hermetically sealed way

c) exposing the assembly to an environment containing compounds which react with the reactive material and

d) comparing the light reflectivity or the light absorption of the layer of reactive material with a calibration value.