Polymerisable LC medium and polymer film with negative optical dispersion

A polymerizable liquid crystal medium comprising one or more compounds of formula A,

• wherein
• P is independently of one another, a polymerizable group,
• Sp is a spacer group or a single bond,
• La is, in case of multiple occurrence identically or differently, F, Cl, CN, SCN, SF5 or a straight-chain or branched, unsubstituted or mono- or polyfluorinated, alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 12 C atoms, or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with up to 5 C atoms,
• r is 0, 1, 2, 3 or 4,
• wherein the amount of compounds of formula A in the medium as a whole is from 5 to 40 wt. %;
• and
• one or more compounds of formula I,
• wherein
• U1,2 are independently of each other selected from
• including their mirror images, wherein the rings U1 and U2 are each bonded to the bridging group —(B)q- via the axial bond, and one or two non-adjacent CH2 groups in these rings are each optionally replaced by O or S, and the rings U1 and U2 are optionally substituted by one or more groups L,
• L is, in case of multiple occurrence identically or differently, P-Sp-, F, Cl, Br, I, —CN, —NO2, —NCO, —NCS, —OCN, —SCN, —C(═O)NR0R00, —C(═O)X, —C(═O)OR0, —C(═O)R0, —NR0R00, —OH, —SF5, optionally substituted silyl, aryl or heteroaryl with up to 12 C atoms, and straight chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with up to 12 C atoms, wherein one or more H atoms are each optionally replaced by F or Cl,
• X is halogen,
• Q1,2 are independently of each other CH or SiH,
• Q3 is C or Si,
• B is in each occurrence independently of one another —C≡C-, —CY1═CY2- or an optionally substituted aromatic or heteroaromatic group,
• Y1,2 are independently of each other H, F, Cl, CN or R0,
• q is an integer from 1 to 10,
• A1-4 are independently of each other selected from non-aromatic, aromatic or heteroaromatic carbocylic or heterocyclic groups, which are unsubstituted or substituted by one or more groups R5, and wherein each of -(A1-Z1)m-U1-(Z2-A2)n- and -(A3-Z3)o—U2-(Z4-A4)p- does not contain more aromatic groups than non-aromatic groups,
• Z1-4 are independently of each other —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR0—, —NR0—CO—, —NR0—CO—NR0—, —OCH2—, —CH2O—, —SCH2—, —CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CH2CH2—, —(CH2)3—, —(CH2)4—, —CF2CH2—, —CH2CF2—, —CF2CF2—, —CH═CH—, —CY1═CY2—, —CH═N—, —N═CH—, —N═N—, —CH═CR0—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR0R00 or a single bond,
• R0 and R00 are independently of each other H or alkyl with 1 to 12 C-atoms,
• m and n are independently of each other 0, 1, 2, 3 or 4,
• o and p are independently of each other 0, 1, 2, 3 or 4,
• R1-5 are independently of each other identical or different groups selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN, —C(═O)NR0R00, —C(═O)X0, —C(═O)R0, —NH2, —NR0R00, —SH, —SR0, —SO3H, —SO2R0, —OH, —NO2, —CF3, —SF5, P—Sp-, optionally substituted silyl, and carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, or denote P or P-Sp-, or are substituted by P or P-Sp-, wherein the compounds comprise at least one group R1-5 denoting or being substituted by P or P-Sp-,
• P is a polymerizable group, and
• Sp is a spacer group or a single bond.