Commissariat a L'energie Atomique

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Commissariat a L'energie

Claude Vauchier

Françoise Vinet

Patrice Caillat

Myriam-Laure Cubizolles

Christine Peponnet

Magalie Faivre

A method of counting thrombocytes contained in a sample of blood, the method having the steps: Apparatus for implementing the method.

Method and apparatus for counting thrombocytes

The invention relates to novel compounds usable as liquid crystals in liquid crystal display devices utilizing the electrically controlled birefringence effect. These compounds comply with formula: ##STR1## in which R.sup.1 represents an alkoxy or alkyl radical with 1 to 12 carbon atoms and Z represents a single bond or a radical chosen from among: ##STR2## provided that R.sup.1 represents an alkyl radical when Z represents a single bond and R.sup.2 represents an alkyl radical with 1 to 12 carbon atoms. They can be obtained by reacting an acid chloride of formula R.sup.1 --z--COCl with a 2,2'-difluoro-4-alkoxy-4'-hydroxydiphenyl of formula: ##STR3##

2,2'-difluoro-4-alkoxy-4'-hydroxydiphenyls and their derivatives, their

The invention relates to novel compounds usable as liquid crystals in liquid crystal display devices utilizing the electrically controlled birefringence effect. These compounds comply with formula: ##STR1## in which R.sup.1 represents an alkoxy or alkyl radical with 1 to 12 carbon atoms and Z represents a single bond or a radical chosen from among: ##STR2## provided that R.sup.1 represents an alkyl radical when Z represents a single bond and R.sup.2 represents an alkyl radical with 1 to 12 carbon atoms. They can be obtained by reacting an acid chloride of formula R.sup.1 --z--COCL with a 2,2'-difluoro-4-alkoxy-4'-hydroxydiphenyl of formula: ##STR3##

The invention relates to a mixture comprising a nematic liquid crystal and a non-mesomorphous compound. The non-mesomorphous compound makes it possible to improve the elastic behavior of the nematic liquid crystal by increasing the value of the ratio K.sub.33 /K.sub.11, in which K.sub.33 represents the elastic bending constant and K.sub.11 the elastic fanning constant of the liquid crystal. The non-mesomorphous compound can be in accordance with the formula: ##STR1## in which R.sup.1 and R.sup.2, which can be the same or different, represent a hydrogen atom or an alkyl radical having 1 to 12 carbon atoms and n is an integer between 2 and 16 and can be associated with liquid crystals or liquid crystal mixtures containing a 1-(alkylcyclohexyl)-2-(alkylfluorobiphenylyl)-ethane. These mixtures can be used as a liquid crystal in a display device.

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Goncelin, France

Claude Vauchier