Active matrix liquid crystal display

Claim 2

An active-matrix liquid crystal display including a liquid crystal panel (50) having a liquid crystal layer (40) in which tilt angle of liquid crystal molecules (35) changes gradually from an upper portion of the liquid crystal panel (50) towards a lower portion of the liquid crystal panel (50).

Claim 3

An active-matrix liquid crystal display comprising: a plurality of first lines (15a-15z); a plurality of pixel electrodes (7) which are connected to the first lines (15a-15z) through capacitors so as to be disposed in a pattern of a matrix; an image signal line (14a-14z); a scanning signal line (13a-13z); a switching element (3) which is electrically connected to the image signal line (14a-14z) and the scanning signal line (13a-13z) and is connected to each of the pixel electrodes (7); a counter electrode (Vt); and liquid crystal (7) which is held between each of the pixel electrodes (7) and the counter electrode (Vt) and is subjected to AC drive; wherein when during an ON period of the switching element (3), an image signal voltage obtained by inverting polarity of a signal voltage is supplied to the pixel electrodes (7) per field of a display screen and during an OFF period of the switching element (3), a first modulation signal having a polarity opposite to that of the image signal voltage is supplied to the first lines (15a-15z) per field of the display screen, potential of the pixel electrodes (7) is changed such that a voltage obtained by adding a change of the potential of the pixel electrodes (7) and the image signal voltage to each other is applied to the liquid crystal (7); wherein the first modulation signals supplied to the first lines (15a-15z), respectively are different from one another.

Claim 4

An active-matrix liquid crystal display comprising: a plurality of first lines (15a-15z); a plurality of pixel electrodes (7) which are connected to the first lines (15a-15z) through capacitors so as to be disposed in a pattern of a matrix; an image signal line (14a-14z); a scanning signal line (13a-13z); a switching element (3) which is electrically connected to the image signal line (14a-14z) and the scanning signal line (13a-13z) and is connected to each of the pixel electrodes (7); a counter electrode (Vt); and liquid crystal (7) which is held between each of the pixel electrodes (7) and the counter electrode (Vt) and is subjected to AC drive; wherein when during an ON period of the switching element (3), an image signal voltage obtained by inverting polarity of a signal voltage is supplied to the pixel electrodes (7) per field of a display screen and during an OFF period of the switching element (3), a first modulation signal having a polarity opposite to that of the image signal voltage is supplied to the first lines (15a-15z) per field of the display screen, potential of the pixel electrodes (7) is changed such that a voltage obtained by eliminating a change of the potential of the pixel electrodes (7) and the image signal voltage to each other is applied to the liquid crystal (7); wherein the first modulation signals supplied to the first lines (15a-15z), respectively are different from one another.

Claim 5

An active-matrix liquid crystal display as claimed in Claim 3, wherein the image signal voltage is obtained by inverting the polarity of the signal voltage per scanning line of the display screen and the polarity of the first modulation signal is inverted per scanning line.

Claim 6

An active-matrix liquid crystal display as claimed in Claim 4, wherein the image signal voltage is obtained by inverting the polarity of the signal voltage per scanning line of the display screen and the polarity of the first modulation signal is inverted per scanning line.

Claim 7

An active-matrix liquid crystal display as claimed in Claim 5, wherein the first modulation signals (Ve(+), Ve(-)) of the opposite polarities have different absolute values.

Claim 8

An active-matrix liquid crystal display as claimed in Claim 6, wherein the first modulation signals (Ve(+), Ve(-)) of the opposite polarities have different absolute values.

Claim 9

An active-matrix liquid crystal display as claimed in Claim 7, wherein prior to lapse of the ON period of the switching element (3), a portion of a potential of the first modulation signal is changed.

Claim 10

An active-matrix liquid crystal display as claimed in Claim 8, wherein prior to lapse of the ON period of the switching element (3), a portion of a potential of the first modulation signal is changed.

Claim 11

An active-matrix liquid crystal display as claimed in Claim 7, wherein the switching element is a thin film transistor (3), wherein supposing that Ve(+) and Ve(-) denote the first modulation signals of the opposite polarities, respectively, Vg denotes a potential change of a scanning signal, Cs denotes a storage capacity, Cgd denotes a capacity between a gate and a drain, Csd denotes a capacity between a source and a drain and ΣC denotes an overall electrostatic capacity per pixel, potential changes Cs·Ve(+)/ΣC and Cs·Ve(-)/ΣC of the pixel electrodes (7) by the first modulation signals and potential change Cgd·Vg/ΣC of the pixel electrodes (7) due to the potential change of the scanning signal have the following relation: Cs·Ve(+)/ΣC + Cgd·Vg/ΣC = Cs·Ve(-)/ΣC - Cgd·Vg/ΣC = △V* where △V* has a value not less than a threshold voltage of the liquid crystal (7).

Claim 12

An active-matrix liquid crystal display as claimed in Claim 8, wherein the switching element is a thin film transistor (3), wherein supposing that Ve(+) and Ve(-) denote the first modulation signals of the opposite polarities, respectively, Vg denotes a potential change of a scanning signal, Cs denotes a storage capacity, Cgd denotes a capacity between a gate and a drain, Csd denotes a capacity between a source and a drain and ΣC denotes an overall electrostatic capacity per pixel, potential changes Cs·Ve(+)/ΣC and Cs·Ve(-)/ΣC of the pixel electrodes (7) by the first modulation signals and potential change Cgd·Vg/ΣC of the pixel electrodes (7) due to the potential change of the scanning signal have the following relation: Cs·Ve(+)/ΣC + Cgd·Vg/ΣC = Cs·Ve(-)/ΣC - Cgd·Vg/ΣC = △V* where △V* has a value not less than a threshold voltage of the liquid crystal (7).

Claim 13

An active-matrix liquid crystal display as claimed in Claim 7, wherein the scanning signal line (13a-13z) acts also as each of the first lines (15a-15z) and the first modulation signal in addition to a scanning signal is applied to the scanning signal line (13a-13z).

Claim 14

An active-matrix liquid crystal display as claimed in Claim 8, wherein the scanning signal line (13a-13z) acts also as each of the first lines (15a-15z) and the first modulation signal in addition to a scanning signal is applied to the scanning signal line (13a-13z).

Claim 15

An active-matrix liquid crystal display as claimed in Claim 13, wherein the first modulation signal Ve(+) of one polarity is supplied to the scanning signal line (13 a-13z) during the OFF period of the switching element (3) in an odd field and the first modulation signal Ve(-) of the other polarity is supplied to the scanning signal line (13a-13z) during the OFF period of the switching element (3) in an even field so as to change the potential of the pixel electrodes (7), wherein supposing that a modulation signal amplitude Vepp is defined as Vepp = |Ve(+) - Ve(-)| , a modulation signal amplitude Vepp(n) for an n-th scanning signal line (13a-13z) and a modulation signal amplitude Vepp(n+1) for an (n+1)-th scanning signal line (13a-13z) have the following relation: Vepp(n) ≦ Vepp(n+1) where character n denotes an arbitrary natural number.

Claim 16

An active-matrix liquid crystal display as claimed in Claim 13, wherein the first modulation signal Ve(+) of one polarity is supplied to the scanning signal line (13 a-13z) during the OFF period of the switching element (3) in an odd field and the first modulation signal Ve(-) of the other polarity is supplied to the scanning signal line (13a-13z) during the OFF period of the switching element (3) in an even field so as to change the potential of the pixel electrodes (7), wherein supposing that a modulation signal amplitude Vepp is defined as Vepp = |Ve(+) - Ve(-)| , a modulation signal amplitude Vepp(n) for an n-th scanning signal line (13a-13z) and a modulation signal amplitude Vepp(n+1) for an (n+1)-th scanning signal line (13a-13z) have the following relation: Vepp(n) ≧ Vepp(n+1) where character n denotes an arbitrary natural number.

Claim 17

An active-matrix liquid crystal display as claimed in Claim 15, wherein the modulation signal amplitude Vepp(n) for the n-th scanning signal line (13a-13z) and the modulation signal amplitude Vepp(n+1) for the (n+1)-th scanning signal line (13a-13z) have the following relation: |Vepp(n) - Vepp(n+1)| = A where character A denotes a constant.

Claim 18

An active-matrix liquid crystal display as claimed in Claim 16, wherein the modulation signal amplitude Vepp(n) for the n-th scanning signal line (13a-13z) and the modulation signal amplitude Vepp(n+1) for the (n+1)-th scanning signal line (13a-13z) have the following relation: |Vepp(n) - Vepp(n+1)| = A where character A denotes a constant.

Claim 19

An active-matrix liquid crystal display comprising: a plurality of first lines; a plurality of pixel electrodes (65) which are connected to the first lines through capacitors so as to be disposed in a pattern of a matrix; an image signal line (61); a scanning signal line (62); a switching element (68) which is electrically connected to the image signal line (61) and the scanning signal line (62) and is connected to each of the pixel electrodes (65); a counter electrode; and liquid crystal which is held between each of the pixel electrodes (65) and the counter electrode and is subjected to AC drive; wherein when during an ON period of the switching element (68), an image signal voltage obtained by inverting polarity of a signal voltage is supplied to the pixel electrodes (65) per field of a display screen and during an OFF period of the switching element (68), a first modulation signal having a polarity opposite to that of the image signal voltage is supplied to the first lines per field of the display screen, potential of the pixel electrodes (65) is changed such that a voltage obtained by adding a change of the potential of the pixel electrodes (65) and the image signal voltage to each other is applied to the liquid crystal; wherein magnitude of storage capacity (63) changes gradually from an upper portion of a liquid crystal panel towards a lower portion of the liquid crystal panel.

Claim 20

An active-matrix liquid crystal display comprising: a plurality of first lines; a plurality of pixel electrodes (65) which are connected to the first lines through capacitors so as to be disposed in a pattern of a matrix; an image signal line (61); a scanning signal line (62); a switching element (68) which is electrically connected to the image signal line (61) and the scanning signal line (62) and is connected to each of the pixel electrodes (65); a counter electrode; and liquid crystal which is held between each of the pixel electrodes (65) and the counter electrode and is subjected to AC drive; wherein when during an ON period of the switching element (68), an image signal voltage obtained by inverting polarity of a signal voltage is supplied to the pixel electrodes (65) per field of a display screen and during an OFF period of the switching element (68), a first modulation signal having a polarity opposite to that of the image signal voltage is supplied to the first lines per field of the display screen, potential of the pixel electrodes (65) is changed such that a voltage obtained by eliminating change of the potential of the pixel electrodes (65) and the image signal voltage to each other is applied to the liquid crystal; wherein magnitude of storage capacity (63) changes gradually from an upper portion of a liquid crystal panel towards a lower portion of the liquid crystal panel.