Polymerisable LC medium and polymer film with flat optical dispersion

A polymerisable LC medium comprising:

• one or more compounds of formula A in an amount of no more than 20% by weight,
• wherein
• P is independently of one another, a polymerisable 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 straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, or alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms,
• r is 0, 1, 2, 3 or 4,
• and 10 to 15% by weight of one or more compounds of formula I,
• wherein
• U1 and U2 are independently of each other selected from
• including their mirror images, wherein the rings U1 and U2 are each bonded to the group —(B)q— via the axial bond, and one or two non-adjacent CH2 groups in these rings are optionally replaced by O and/or S, and the rings U1 and U2 are optionally substituted by one or more groups L,
• Q1 and Q2 are independently of each other CH or SiH,
• Q3 is C or Si,
• B is in each occurrence independently of one another —C≡—, —CY1═CY2— or an optionally substituted aromatic or heteroaromatic group,
• Y1 and Y2 are independently of each other H, F, Cl, CN or R0,
• q is an integer from 1 to 10,
• A1 to A4 are independently of each other, in each occurrence selected from non-aromatic, aromatic or heteroaromatic carbocylic or heterocyclic groups, which are optionally 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 to Z4 are independently of each other, in each occurrence, —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,
• and p are independently of each other 0, 1, 2, 3 or 4,
• R1 to R5 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, or 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,
• Sp is a spacer group or a single bond.