DE2404044A1 - SUPPORT PLATE FOR MICRO ENCAPSULATED LIQUID CRYSTALS FOR THERMOGRAPHICAL EXAMINATIONS - Google Patents

Description

I Please state my reference

Dipl.-Ing. E. Tergau [T5 / 31 040027)

Patent attorney

Nuremberg, the -. ·,.

24Q40U

Eurand S.p.A. and Dr. Franco di Roberto, Milan / Italy

Support plate for micro-encapsulated liquid crystals for thermographic examinations

The invention relates to a support plate for microencapsulated liquid crystals (hereinafter abbreviated to MKK) for thermographic examinations, especially in the diagnostic field, in which the supporting material for the MKK is a very thin and extremely flexible plastic material that allows rapid vertical heat transfer through the plate not hindered in this way an expansion and weakening of the colored point to be tested during the to avoid thermographic examination «,

The invention relates to a support plate for MKK for use in thermographic examinations, which avoids the disadvantages which have been shown up to now in the techniques of thermographic examinations with the aid of liquid crystals _{or the like}

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Nuremberg 11 Telephone (0911) Telex Telegrams Deutsche Bank Bayer. Vereinsbank Stadtsparkasse Postscheckkonto

Hefnersplatz 3 204081-83 06/22327 "Patwetzel" Nbg. 368910 Nbg. 6311695 1528 354 Nuremberg 11151-653

It is known that liquid crystals are mesophormic State are those substances that are involved in the transition from the solid to the liquid phase assume an intermediate phase, called the mesophase, in which they simultaneously a double refraction and related phenomena of the crystal state as well as other properties that are characteristic of the liquid state, such as flowability and surface tension. These liquid crystals also exist in three states, depending on the nature of the substance and the nature of the steric arrangement of the molecules of the substance, the one of which is commonly considered in thermography is drawn to the cholesteric structure that is involved liquid cholesteric crystal, which is by far the most widely used because of its sensitivity and the accuracy in the representation of temperature changes by successive passes through the whole visible spectrum, if correctly formulated »For the application of liquid crystals in thermography, for example For medical diagnoses, since the cholesteric substances that are applied must be viscous liquids which are handled with difficulty and easily changed, these are applied in MKK form, in other words, enclosed in capsules of microscopic size, formed by coacervation around these liquids Crystals are obtained,

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However, even in this way, the application of MKK to the patient's body presents considerable difficulties because it is necessary to first apply a black background to the part to be tested in order to absorb the frequencies which are not selectively reflected during the reflect the thermographic image of the surface to be tested _{o However,} it is difficult to find opaque black inks that are non-toxic and as a result can be applied directly to the skin _o

Another disadvantage is the evaporation of the organic solvent of the black background, which is a caused an initial decrease in temperature, followed by a stop and subsequent increase due to the interference on the physiological process of heat loss, and also on account of physical reasons which are characteristic for the properties of the black body are so that the resolving power of the thermographic image is low is and practical as a progressive defocalization or Attenuation of the thermographic image appears »

In addition, spraying the black layer or the MKK does not guarantee that it will spread evenly or a uniform thickness of the two layers with the

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Consequence of possible errors in the evaluation of the thermographic level ο The method is not sufficient for mass application, since it is time consuming in practical use and has the serious disadvantage that it is not possible to carry out another thermographic test with a different type of MCK in the course of the same test,

US Pat. No. 3,114,836 discloses the use of a plate which can be placed against the part of the body to be tested and which consists of a frame which carries a plate of flexible plastic material onto which the black background and the MKK are spread are _o In the description of the preparation of such a plate it is indicated that the carrier material should be firm to allow a certain compression on the body surface of the patient, but at the same time flexible to follow its contour Patent specification are processed, however, have the disadvantage that they offer a strong obstacle to the passage of heat, which is scattered both vertically and horizontally, so that an expansion and weakening of the colored point to be tested occurs during the thermographic test. The invention is eliminated these disadvantagesο

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It is based on the knowledge that the obstacle that an application of thermography in the diagnostic field in the nature and thickness of the support used for the thermographic plate,

The invention eliminates the aforementioned difficulties in that as a carrier material for the MKK and the black Background a very thin and extremely flexible material is used that has a very fast vertical Heat transfer guaranteed and lateral scattering prevented «,

Practically, it was found that excellent properties show such plastic materials, which can form a very thin film, less than 50 microns, 'Highlighted _t Without being limited thereto, are: polyvinyl chloride; Vinyl chloride + vinylidene chloride (SARAN); Polyethylene terephthalate (Mylar), vinyl chloride (DOMOPACK); Polyesters, copolymers of ethylene and vinyl acetate; Copolymers of Vinyl Chloride and Acetates In addition, in the prior art patents, the black background and the MKK are spread on the plastic support with very complicated and outdated hand systems. In contrast, when using the thin plastic films according to the invention, which can also easily be a printing process

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can undergo, both the black background and the MKK applied to the support made of plastic material by a silk screen process, which is particularly suitable for the application of substances of this type _o It is described in US Pat. No. 3,578,482

However, it is also possible to use other methods for applying the black background or the MKK, such as spraying, barrel spraying, air knife or other equivalent systems, or even with a self-adhesive backing or a black plastic carrier to avoid the application of the black background «

In this way, the layer of the MKK, which is produced according to French patent specification 1,527,432, for example can be perfectly uniform and gives excellent results which when placed against the skin of the Adheres patient, very well defined points in the hotter spots that can be seen immediately, the points lasting for a considerable long time without undergoing any change to practical perception to give that heat is not horizontal, i. across the plate diffused.,

Some examples are given below for illustration, to which the invention is not limited, but

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Practical embodiments explain in quantitative terms the various steps involved in preparing the To describe plate »

Example I:

A lot is put on a PVC sheet with a thickness of 10 microns and with the help of a standard silk grid frame

applied from 2-15 g / cm of a quick-drying black paint with an opaque appearance with a high pigment concentration O

When the paint is dry, a mixture of MKK type R 28 and a binder (polyvinyl alcohol) is made in water is dissolved in a ratio of 1: 1 to 4: 1, with. Using a silk grid frame made of polyester fabric with a mesh size of 8 microns (N 20-2 "9 mils) applied"

A rounded doctor blade made of extra-soft neoprene (Durometer No. ₀ approx. 45-50) was used for the order.

2
to apply 20-40 g / m of MKK and Binder (when dry) and to apply a transparent protective coating using a normal frame in a further pass of a silk grid «»

Example II:

On a sheet of polyethylene terephthalate with a thickness

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2 of 23 microns with a tensile strength of 1750 kgf / cm and

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a coefficient of thermal conductivity χ 8 _O 96 10 ^were

A quantity of 2-15 g / m 2 of an alcohol-resistant, flexible, glossy varnish was applied with a silver grid frame No. 25, dried fairly quickly in air and placed in an oven for a few minutes _e

After the paint had dried, a mixture of MKK type R 32 and a binder (polyvinylpyrolides) was dissolved in water in a ratio of 1: 1 to 1: 4 using a silk grid frame made of polyester fabric with a mesh size of 200 microns ,, Contrary to example I, a doctor blade normal hardness (durometer No. ₀ 70-75) with square edge, since it is not necessary to take special measures because the mesh size of the silk grid is wider _e In this manner, 20-45

g / m applied by the MKK (value measured after drying) "

It is understandable that the various combinations, variations, additions and substitutions of elements and Work steps for the skilled person result without the area of the invention as defined in the claims o

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Claims (5)

24U4U4A patent claims 1.) Support plate for microencapsulated "liquid crystals for thermographic monitoring with the indication that the carrier material for the MKK is a very thin and extremely flexible plastic material is ^ that the fast vertical Heat transfer through this plate is not prevented. 2 ο plate according to claim 1, wherein the plastic material is in the form of a very thin film with a thickness of less than 50 microns _o 3ο plate according to claim 2, wherein the carrier material in in the form of a very thin film is selected from the group consisting of: polyvinyl chloride, vinyl chloride and Vinylidene chloride; Polyethylene terephthalate, vinyl chloride, polyester, copolymers of ethylene and vinyl acetate, copolymers of vinyl chloride and acetates 4. Plate according to one of claims 1-3, at dör the two Layers of MKK and black background are applied to the support film by a silk screen process. 4098A1 / 0914 " ¹⁰ ". 24Ü4ÜU 5. Plate according to one of claims 1-3, in which the layer of the MKK and the black background by spraying, distributing with air knife or cylinder or equivalent processes are applied. 60 panel according to claims 1-3, wherein the plastic carrier is black, so that the application of a black background is avoided. 7ο plate according to one or more of the previous claims which the MKK are applied in the form of a mixture with a suitable binder. 80 plate according to one or more of the preceding claims, in which the layer of MKK and binders that are on the plastic Carrier is applied, 20-45 g / m when dry amount 409841/0914