GB2145224A - Thermochromic liquid crystal devices - Google Patents

Thermochromic liquid crystal devices Download PDF

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Publication number
GB2145224A
GB2145224A GB08420800A GB8420800A GB2145224A GB 2145224 A GB2145224 A GB 2145224A GB 08420800 A GB08420800 A GB 08420800A GB 8420800 A GB8420800 A GB 8420800A GB 2145224 A GB2145224 A GB 2145224A
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GB
United Kingdom
Prior art keywords
liquid crystal
backing
sheet
tape
layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08420800A
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GB8420800D0 (en
Inventor
Christopher John Dennis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of GB8420800D0 publication Critical patent/GB8420800D0/en
Publication of GB2145224A publication Critical patent/GB2145224A/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
    • G01K11/12—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance
    • G01K11/16—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance of organic materials
    • G01K11/165—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance of organic materials of organic liquid crystals

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Liquid Crystal (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)

Abstract

A temperature sensitive liquid crystal device comprises a flexible tape including a transparent flexible sheet A onto which is applied a thin layer B of thermochromic liquid crystal, and a backing C with an adhesive layer D applied to the liquid crystal layer. The tape may be used to produce a liquid crystal transfer. In this case the tape is adhered to the surface by layer D and the transparent flexible sheet is then removed. The backing C may comprise PVA impregnated with carbon black. <IMAGE>

Description

SPECIFICATION Thermochromic liquid crystal devices This invention relates to an improved liquid crystal device for monitoring the temperature of different points on a surface.
Thermochromic liquid crystals are now widely used for measuring and mapping temperatures since they change colour at a predetermined temperature.
According to this invention a liquid crystal device for monitoring the temperature across a surface comprises a flexible tape including a transparent flexible sheet onto which is applied a thin layer of thermochromic liquid crystal, and a backing which is applied to the liquid crystal layer, the flexible tape being applied to the surface by adhering the backing to the surface.
The backing is preferably black and may be polyvinyl acetete (PVA) with carbon black.
The transparent tape is preferably PVC and may be made in rolls of various widths. The thickness may for example be 100-500 gauge.
Preferably the backing is self-adhesive so that the liquid crystal is brought into direct and intimate contact with the surface with little chance of any trapped air beneath the tape thus ensuring an accurate colour display.
The liquid crystal formulation may be a dispersion from solution, a dispersion from emulsion or in a micro-encapsulated form. A useful example is a dispersion from emulsion, of 30% liquid crystal in gum arabic with a temperature range of 30.1"C to 40.6"C.
Preferably the range of temperatures of the liquid crystal is between 15 and 40"C.
If liquid crystals in microencapsulated form are used then liquid crystals with different temperature ranges may be used in combination to provide a more accurate measure of temperature.
An alternative layer of liquid crystal is formed using a solution of liquid crystal in methyl chloroform in conjunction with a polymer solution.
Very small quantities of liquid crystal are required on such a tape to give good colour display per unit length of tape. This means that the tape provides a relatively cheap way of providing the temperature monitoring of a surface.
According to further aspect of this invention a method of applying a thin layer of liquid crystal to a surface to be temperature monitored comprising the steps of applying a liquid crystal tape comprising a backing layer and a thin layer of liquid crystal applied to a flexible plastics sheet, on to the surface by adhering the backing to the surface, and subsequently removing the flexible plastics sheet.
Since the liquid crystal is left as a transfer on the surface, it can be used with either a smooth even surface, or can be used with an uneven surface.
The plastic sheet may be polythene, PVC, PVA or any other suitable polycarbonate.
The plastics sheet is removable, once the backing has been adhered to the surface so that a liquid crystal transfer is left adhered to the surface. This means that very thin layers of liquid crystal may be applied to surfaces so that the transfer will then adhere to an uneven surface such as skin.
Also according to this invention there is provided a liquid crystal transfer comprising a backing sheet, and a layer of liquid crystal applied to a flexible plastics sheet, the flexible plastics sheet being removable when the backing sheet has been adhered to a surface, so that the backing sheet and liquid crystal layer are left adhered to the surface.
The backing sheet may be adhered to the surface by using any suitable adhesive such as gum arabic or the backing sheet may be self-adhesive.
Such transfers are most useful in the application of thin layers of liquid crystal of skin or any other uneven surfaces.
This means that the liquid crystal transfer may be used to may venous flow of an area infection on any uneven stretch of skin on a human or animal body.
The liquid crystal transfer is especially useful for investigating points of infection on an animals foot, such as cows or horses hooves.
Where the transfer is to be used to monitor infection the actual level of temperature at a point is not most important. It is more important to measure temperature differences at different points.
Preferably the liquid crystal used is a mixture of liquid crystals so that temperatures in a range 150C to 40"C can be measured.
An example of liquid crystal tape and transfer in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure lisa schematic view of liquid crystal tape; and, Figure 2 is a schematic view of the transfer.
Athin layer of liquid crystal B is applied to the transparent PVC tape A. The liquid crystal is a disperiosn from an emulsion carried in gum arabic with a temperature range of 30.1"C to 40.6"C. A black backing C is applied to the liquid crystal layer. The backing C is PVA with carbon black. A self-adhesive layer D is applied to the back of the backing. The tape is made in rolls of different widths.
The transfer comprises a 250 gauge polythene sheet 1 to which is applied by screen printing liquid crystal layer 2 and the black backing 3 of black PVA paint is screened on top 2. The surface to be mapped is lightly coated with gum arabic and the transfer is then pressed onto the surface with the backing 3 closest to the surface. The polythene sheet 1 is then peeled away leaving the liquid crystal and the backing on the surface.
1. A liquid crystal device for monitoring the temperature across a surface comprising a flexible tape including a transparent flexible sheet onto which is applied a thin layer of thermochromic liquid crystal, and a backing which is applied to the liquid crystal layer, the flexible tape being applied to the surface by adhering the backing to the surface.
2. A liquid crystal device according to claim 1 in which the backing is black.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (15)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Thermochromic liquid crystal devices This invention relates to an improved liquid crystal device for monitoring the temperature of different points on a surface. Thermochromic liquid crystals are now widely used for measuring and mapping temperatures since they change colour at a predetermined temperature. According to this invention a liquid crystal device for monitoring the temperature across a surface comprises a flexible tape including a transparent flexible sheet onto which is applied a thin layer of thermochromic liquid crystal, and a backing which is applied to the liquid crystal layer, the flexible tape being applied to the surface by adhering the backing to the surface. The backing is preferably black and may be polyvinyl acetete (PVA) with carbon black. The transparent tape is preferably PVC and may be made in rolls of various widths. The thickness may for example be 100-500 gauge. Preferably the backing is self-adhesive so that the liquid crystal is brought into direct and intimate contact with the surface with little chance of any trapped air beneath the tape thus ensuring an accurate colour display. The liquid crystal formulation may be a dispersion from solution, a dispersion from emulsion or in a micro-encapsulated form. A useful example is a dispersion from emulsion, of 30% liquid crystal in gum arabic with a temperature range of 30.1"C to 40.6"C. Preferably the range of temperatures of the liquid crystal is between 15 and 40"C. If liquid crystals in microencapsulated form are used then liquid crystals with different temperature ranges may be used in combination to provide a more accurate measure of temperature. An alternative layer of liquid crystal is formed using a solution of liquid crystal in methyl chloroform in conjunction with a polymer solution. Very small quantities of liquid crystal are required on such a tape to give good colour display per unit length of tape. This means that the tape provides a relatively cheap way of providing the temperature monitoring of a surface. According to further aspect of this invention a method of applying a thin layer of liquid crystal to a surface to be temperature monitored comprising the steps of applying a liquid crystal tape comprising a backing layer and a thin layer of liquid crystal applied to a flexible plastics sheet, on to the surface by adhering the backing to the surface, and subsequently removing the flexible plastics sheet. Since the liquid crystal is left as a transfer on the surface, it can be used with either a smooth even surface, or can be used with an uneven surface. The plastic sheet may be polythene, PVC, PVA or any other suitable polycarbonate. The plastics sheet is removable, once the backing has been adhered to the surface so that a liquid crystal transfer is left adhered to the surface. This means that very thin layers of liquid crystal may be applied to surfaces so that the transfer will then adhere to an uneven surface such as skin. Also according to this invention there is provided a liquid crystal transfer comprising a backing sheet, and a layer of liquid crystal applied to a flexible plastics sheet, the flexible plastics sheet being removable when the backing sheet has been adhered to a surface, so that the backing sheet and liquid crystal layer are left adhered to the surface. The backing sheet may be adhered to the surface by using any suitable adhesive such as gum arabic or the backing sheet may be self-adhesive. Such transfers are most useful in the application of thin layers of liquid crystal of skin or any other uneven surfaces. This means that the liquid crystal transfer may be used to may venous flow of an area infection on any uneven stretch of skin on a human or animal body. The liquid crystal transfer is especially useful for investigating points of infection on an animals foot, such as cows or horses hooves. Where the transfer is to be used to monitor infection the actual level of temperature at a point is not most important. It is more important to measure temperature differences at different points. Preferably the liquid crystal used is a mixture of liquid crystals so that temperatures in a range 150C to 40"C can be measured. An example of liquid crystal tape and transfer in accordance with the invention will now be described with reference to the accompanying drawings in which: Figure lisa schematic view of liquid crystal tape; and, Figure 2 is a schematic view of the transfer. Athin layer of liquid crystal B is applied to the transparent PVC tape A. The liquid crystal is a disperiosn from an emulsion carried in gum arabic with a temperature range of 30.1"C to 40.6"C. A black backing C is applied to the liquid crystal layer. The backing C is PVA with carbon black. A self-adhesive layer D is applied to the back of the backing. The tape is made in rolls of different widths. The transfer comprises a 250 gauge polythene sheet 1 to which is applied by screen printing liquid crystal layer 2 and the black backing 3 of black PVA paint is screened on top 2. The surface to be mapped is lightly coated with gum arabic and the transfer is then pressed onto the surface with the backing 3 closest to the surface. The polythene sheet 1 is then peeled away leaving the liquid crystal and the backing on the surface. CLAIMS
1. A liquid crystal device for monitoring the temperature across a surface comprising a flexible tape including a transparent flexible sheet onto which is applied a thin layer of thermochromic liquid crystal, and a backing which is applied to the liquid crystal layer, the flexible tape being applied to the surface by adhering the backing to the surface.
2. A liquid crystal device according to claim 1 in which the backing is black.
3. A liquid crystal device according to claim 2 in which the backing is polyvinyl acetete (PVA) with carbon black.
4. A liquid crystal device according to any one of the preceding claims in which the transparent sheet is PVC.
5. A liquid crystal device according to any of the preceding claims in which the thickness of the transparent sheet is in the range 100-150 gauge.
6. A liquid crystal device according to any one of the preceding claims in which the backing is selfadhesive.
7. A liquid crystal device according to any one of the preceding claims in which the liquid crystal formulation is a dispersion from solution, a dispersion from emulsion or in a microencapsulated form.
8. A liquid crystal device according to any one of the preceding claims in which the liquid crystal is a dispersion from emulsion of 30% liquid crystal in gum arabic with a temperature range of 30.1"C to 40.6 C.
9. A liquid crystal device according to any one of claims 1 to 7 in which the liquid crystal is formed using a solution of liquid crystal in methyl chloroform in conjunction with a polymer solution.
10. A method of applying a thin layer of liquid crystal to a surface to be temperature monitored comprising the steps of applying a liquid crystal tape comprising a backing layer and a thin layer of liquid crystal applied to flexible plastic sheet, on to the surface by adhering the backing to the surface, and subsequently removing the plastics sheet.
11. A liquid crystal transfer comprising a backing sheet, and a layer of liquid crystal applied to a flexible plastics sheet, the flexible plastics sheet being removable when the backing sheet has been adhered to a surface, so that the backing sheet and liquid crystal layer are left adhered to the surface.
12. A liquid crystal transfer according to claim 11, for detecting infection in an animals foot.
13. A liquid crystal device according to claim 1, arranged substantially as described herein with reference to Figure 1 of the accompanying drawings.
14. A method of applying a thin layer of liquid crystal to a surface to be temperature monitored according to claim 10, substantially as herein described.
15. A liquid crystal transfer according to claim 11, arranged substantially as herein described with reference to Figure 2 of the accompanying drawings.
GB08420800A 1983-08-16 1984-08-16 Thermochromic liquid crystal devices Withdrawn GB2145224A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB838322045A GB8322045D0 (en) 1983-08-16 1983-08-16 Thermochromic liquid crystal devices

Publications (2)

Publication Number Publication Date
GB8420800D0 GB8420800D0 (en) 1984-09-19
GB2145224A true GB2145224A (en) 1985-03-20

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GB838322045A Pending GB8322045D0 (en) 1983-08-16 1983-08-16 Thermochromic liquid crystal devices
GB08420800A Withdrawn GB2145224A (en) 1983-08-16 1984-08-16 Thermochromic liquid crystal devices

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GB838322045A Pending GB8322045D0 (en) 1983-08-16 1983-08-16 Thermochromic liquid crystal devices

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0223604A2 (en) * 1985-11-19 1987-05-27 Coloplast A/S A water bag for irrigating the colon
DE9208404U1 (en) * 1992-06-24 1992-09-03 Haag, Volker, 7630 Lahr, De
WO1994028982A1 (en) * 1993-06-11 1994-12-22 Multivision Holdings Ltd. Golf club strike indicator
WO2000000004A1 (en) * 1998-06-26 2000-01-06 Medical Indicators, Inc. Liquid crystal thermometer
WO2000025131A1 (en) * 1998-10-23 2000-05-04 The Horticulture And Food Research Institute Of New Zealand Limited Determining meat quality of a live animal
WO2001004694A1 (en) * 1999-07-12 2001-01-18 Array Displays Ab Display
WO2005084195A2 (en) * 2004-02-09 2005-09-15 Equitemp, Inc. Hoof temperature sensor
EP2130520A1 (en) 2008-06-05 2009-12-09 DePuy International Limited Device for measuring the temperature of bone cement
CN106525272A (en) * 2016-10-12 2017-03-22 清华大学 Temperature sensitive biosensor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1344206A (en) * 1972-05-09 1974-01-16 Johnson & Johnson Temperature sensing patch
GB1494256A (en) * 1974-03-12 1977-12-07 Agfa Gevaert Ag Method of measuring a two-dimensional temperature distribution
EP0004464A2 (en) * 1978-03-23 1979-10-03 Liquid Crystal Products, Inc. Polyvinyl butyral-liquid crystal film-forming composition and its use
GB2034033A (en) * 1978-09-05 1980-05-29 Gen Electric Temperature Indicator
GB2086575A (en) * 1980-07-30 1982-05-12 Colombo Aldo Temperature-responsive screen to detect temperature anomalies of the skin

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1344206A (en) * 1972-05-09 1974-01-16 Johnson & Johnson Temperature sensing patch
GB1494256A (en) * 1974-03-12 1977-12-07 Agfa Gevaert Ag Method of measuring a two-dimensional temperature distribution
EP0004464A2 (en) * 1978-03-23 1979-10-03 Liquid Crystal Products, Inc. Polyvinyl butyral-liquid crystal film-forming composition and its use
GB2034033A (en) * 1978-09-05 1980-05-29 Gen Electric Temperature Indicator
GB2086575A (en) * 1980-07-30 1982-05-12 Colombo Aldo Temperature-responsive screen to detect temperature anomalies of the skin

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0223604A3 (en) * 1985-11-19 1989-06-21 Coloplast A/S A water bag for irrigating the colon
EP0223604A2 (en) * 1985-11-19 1987-05-27 Coloplast A/S A water bag for irrigating the colon
DE9208404U1 (en) * 1992-06-24 1992-09-03 Haag, Volker, 7630 Lahr, De
WO1994028982A1 (en) * 1993-06-11 1994-12-22 Multivision Holdings Ltd. Golf club strike indicator
WO2000000004A1 (en) * 1998-06-26 2000-01-06 Medical Indicators, Inc. Liquid crystal thermometer
US6862550B1 (en) 1998-10-23 2005-03-01 The Horticulture And Food Research Institute Of New Zealand Limited Determining meat quality of a live animal
WO2000025131A1 (en) * 1998-10-23 2000-05-04 The Horticulture And Food Research Institute Of New Zealand Limited Determining meat quality of a live animal
WO2001004694A1 (en) * 1999-07-12 2001-01-18 Array Displays Ab Display
WO2005084195A2 (en) * 2004-02-09 2005-09-15 Equitemp, Inc. Hoof temperature sensor
WO2005084195A3 (en) * 2004-02-09 2006-05-04 Equitemp Inc Hoof temperature sensor
EP2130520A1 (en) 2008-06-05 2009-12-09 DePuy International Limited Device for measuring the temperature of bone cement
CN106525272A (en) * 2016-10-12 2017-03-22 清华大学 Temperature sensitive biosensor
CN106525272B (en) * 2016-10-12 2018-11-09 清华大学 Thermo-sensitive biosensor

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Publication number Publication date
GB8322045D0 (en) 1983-09-21
GB8420800D0 (en) 1984-09-19

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