| 摘要 |
Provided is a crystalline compound comprising benzochromene structure having electrophilic element in middle ring of the structure, thereby to exhibit high negative dielectric constant anisotropy and refractive index anisotropy, and other physical properties such as rapid response velocity, threshold voltage, stability and voltage maintenance factor useful for crystalline medium. The crystalline compound is represented by formula 1 (wherein A is -CXY-, X and Y are independently hydrogen, halogen atom, -CN, -CX'3, -NCS, -SX'5 or -OCX'3 for X' as halogen atom; B1, B2, B3, B4, B5 and B6 are independently hydrogen, halogen atom or C1-C5 alkyl group; R1 and R2 are independently C1-C20 alkyl, cycloalkyl, alkoxy, alkenyloxy or alkenyl group; C1 and C2 are independently single bond, -O-, -S-, -CH2-, -CH2CH2-, -CHCH-, -C=C-, -CF2O-, -OCF2-, -COO-, -OCO-, -CS-, -CH2O-, -OCH2-, -NN- or -NON-; D1 and D2 are independently single bond or various benzene rings; Y is O, S or Se; and m and n are independently 0 to 2). The crystalline medium comprises 3 to 80 wt.% of the crystalline compound of formula 1. The crystalline medium is used to manufacture a crystalline display, especially, in TFT driving type using VA and IPS mode.
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