Systems and methods for measuring tension distribution in webs of roll-to-roll processes

Patent metadata

Field	Value
Publication number	US-12429390-B2
Application number	US-202218002350-A
Country	US
Kind code	B2
Filing date	Apr 5, 2022
Priority date	Apr 5, 2021
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

Systems and methods for measuring web tension distribution in roll-to-roll processes, for example, such as R2R processes employed in the fabrication of printed devices. Such systems and methods entail a web that travels between first and second rollers in a longitudinal direction of the web, inducing tension in the web in the longitudinal direction thereof such that tension is present in a flexible substrate of the web between the first and second rollers, and operating the system to determine an average tension and linear variation of tension present in the flexible substrate resulting from the tension induced in the web inducing a nonuniform tension distribution in the flexible substrate between the first and second rollers. The systems and methods utilize one or more devices that induce deflection in the web between the first and second rollers.

First claim

The invention claimed is:

1. A system for monitoring tension distribution across a width of a web in a roll-to-roll system, the roll-to-roll system comprising the web, at least first and second rollers between which the web travels in a longitudinal direction of the web, tension inducing means for inducing tension in the web in the longitudinal direction thereof, and fabricating means for fabricating printed devices on a surface of a flexible substrate of the web, the system comprising:
a first device for inducing deflection in the web by exciting vibration in the web without contacting the web between the first and second rollers;
a second device for sensing vibration in the web in a transverse direction that is normal to the surface of the flexible substrate without contacting the web; and
one or more computer processors configured to:
process vibrational responses induced by the first device and sensed by the second device at a plurality of different locations across a width of the web while the first device is located at a single location along the width of the web; and
determine from the processed vibrational responses an average tension and linear variation of tension present in the flexible substrate resulting from a nonuniform tension distribution induced in the flexible substrate between the first and second rollers.

2. The system according to claim 1 , wherein the first device comprises a speaker, and wherein the one or computer processors are configured to drive the speaker with a chirp signal to excite the vibrations in the web.

3. The system according to claim 1 , wherein
the second device detects resonance frequencies of vibration in the web in the transverse direction; and
the one or more computer processors are configured to calculate the average tension and the linear variation of tension based on the resonance frequencies of vibration.

4. The system according to claim 3 , wherein the one or more computer processors are configured to calculate the average tension and linear variation of tension present in the flexible substrate using a tensioned Kirchhoff plate model to define spatial dependence of eigenmodes across the width of the web based on the resonance frequencies of vibration detected by the second device at the plurality of different locations.

5. The system according to claim 4 , wherein the resonance frequencies detected by the second device are the two lowest resonance frequencies of vibration in the web obtained based at least in part on a transfer function of the web based on a ratio of amplitudes and differences of phases of a measurement on the web and a measurement directly on the speaker.

6. The system according to claim 5 , wherein the web is in and contacted by a fluid between the first and second rollers.

7. The system according to claim 6 , wherein the one or more computer processors are configured to model the fluid as an inviscid, incompressible fluid and to estimate the effect of aerodynamic loading on the resonance frequencies and eigenmodes of the web.

8. The system according to claim 1 , wherein the web is in a vacuum between the first and second rollers.

9. The system according to claim 1 , further comprising means for controlling the tension induced in the web to increase uniformity of the tension distribution present in the flexible substrate between the first and second rollers.

10. A method of monitoring tension distribution across a width of a web in a roll-to-roll process, the method comprising:
causing the web to travel between first and second rollers in a longitudinal direction of the web;
inducing tension in the web in the longitudinal direction thereof such that tension is present in a flexible substrate of the web between the first and second rollers; and
inducing deflections in the web by exciting vibrations in the web without contacting the web at a first fixed location between the first and second rollers;
sensing, while the deflections are induced at the first fixed location, vibrations in the web in a transverse direction that is normal to a surface of the flexible substrate without contacting the web at a plurality of second locations across the width of the web; and
determining from the sensed vibrations an average tension and linear variation of tension present in the flexible substrate resulting from the tension induced in the web inducing a nonuniform tension distribution in the flexible substrate between the first and second rollers.

11. The method according to claim 10 , wherein the first device comprises a speaker, and wherein the step of inducing deflections comprises driving the speaker with a chirp signal to excite the vibrations in the web.

12. The method according to claim 11 , further comprising:
detecting resonance frequencies of vibration in the web in the transverse direction; and
calculating the average tension and the linear variation of tension based on the resonance frequencies of vibration.

13. The method according to claim 12 , wherein the step of determining comprises using a tensioned Kirchhoff plate model to define spatial dependence of eigenmodes across the width of the web to calculate the average tension and the linear variation of tension based on the resonance frequencies of vibration.

14. The method according to claim 13 , wherein the resonance frequencies detected are the two lowest resonance frequencies of vibration in the web obtained using a transfer function of the web based on a ratio of amplitudes and differences of phases of a measurement on the web and a measurement directly on the speaker.

15. The method according to claim 12 , wherein the web is in and contacted by a fluid between the first and second rollers.

16. The method according to claim 15 , wherein the fluid is modeled as an inviscid, incompressible fluid and used to estimate the effect of aerodynamic loading on the resonance frequencies and eigenmodes of the web.

17. The method according to claim 10 , wherein the web is in a vacuum between the first and second rollers.

18. The method according to claim 10 , further comprising controlling the tension induced in the web to increase uniformity of the tension distribution present in the flexible substrate between the first and second rollers.

19. The method according to claim 10 , further comprising printing one or more printed devices on a surface of the flexible substrate, wherein the printed devices are chosen from the group consisting of electronic, optical, and optoelectronic devices.

20. The method according to claim 19 , wherein the printed devices are chosen from the group consisting of thin film transistors, supercapacitors, organic light emitting diodes, solar cells, antennas, and sensors.

Assignees

• Purdue Research Foundation

Inventors

• Feng Dan
• Wagner Ryan
• Raman Arvind

Classifications

• B65H2553/30

  using acoustic or ultrasonic elements · CPC title

• G01L5/045

  for measuring the tension across the width of a band-shaped flexible member (measuring flatness G01B) · CPC title

• B65H23/044 Primary

  Sensing web tension (B65H23/06, B65H23/18 take precedence) · CPC title

• B65H2701/19

  Specific article or web · CPC title

• B65H2515/314

  Tension profile, i.e. distribution of tension, e.g. across the material feeding direction or along diameter of web roll · CPC title