Liquid crystal display device
View Patent ↗The OCB mode liquid crystal display device applies a black display voltage V(Tr) with temperature characteristic requirements expressed by: V ( T )=< Vs ( T ), and V ( Tr−ΔT )= V ( T )=< Vs ( Tr ), where T represents a panel temperature of the liquid crystal panel, Tr represents a sensed temperature, ΔT represents a temperature difference between the panel temperature and the sensed temperature, and Vs(T) represents an optimal black display voltage.
1. A liquid crystal display device comprising:
an OCB mode liquid crystal panel including a pair of substrates and a liquid crystal layer held between the paired substrates;
a temperature-sensing unit configured to sense a temperature on or around a periphery of the liquid crystal panel when the liquid crystal panel is installed in a housing; and
a control unit configured to set a black display voltage that is to be applied to the liquid crystal layer;
wherein the control unit produces a corrected sensed temperature by subtracting a predetermined correction amount from the sensed temperature sensed by the temperature-sensing unit, and controls the black display voltage based on the corrected sensed temperature, and
the control unit produces the black display voltage which is kept constant, if and when the corrected sensed temperature is at or below a particular temperature.
2. The liquid crystal display device according to claim 1 , wherein, by a control of the control unit, the black display voltage is decreased with an increase of the corrected temperature in accordance with a curve of an optimal black display voltage, if and when the corrected sensed temperature is above a particular temperature.
3. The liquid crystal display device according to claim 1 , wherein, by a control of the control unit, the black display voltage is raised, if and when the corrected sensed temperature is on or below a predetermined temperature, so as not to exceed the optimal black display voltage.
4. The liquid crystal display device according to claim 1 , wherein the particular temperature is around 35° C.
5. The liquid crystal display device according to claim 1 , wherein the predetermined correction amount is around 10° C.
6. The liquid crystal display device of claim 1 , further comprising a first memory that stores the predetermined correction amount.
7. The liquid crystal display device of claim 6 , wherein the first memory is configured to be rewritable.
8. The liquid crystal display device of claim 1 , further comprising a second memory that stores a correction table of the black display voltage.
9. The liquid crystal display device of claim 1 , wherein the temperature-sensing unit is a digital temperature sensor.
10. The liquid crystal display device of claim 1 , wherein the control unit controls the black display voltage based on the sensed temperature sensed by the temperature-sensing unit when the sensed temperature is below a particular temperature.
11. The liquid crystal display device of claim 10 , wherein the particular temperature is set to a temperature within a range of 25 to 50° C.
12. The liquid crystal display device of claim 1 , wherein the control unit controls the black display voltage based on the sensed temperature sensed by the temperature-sensing unit until elapsing a predetermined length of time from power on.
13. A liquid crystal display device comprising:
an OCB mode liquid crystal panel including a pair of substrates and a liquid crystal layer held between the paired substrates;
a temperature-sensing unit configured to sense a temperature on or around a periphery of the liquid crystal panel when the liquid crystal panel is installed in a housing; and
a control unit configured to set a black display voltage that is to be applied to the liquid crystal layer;
wherein the control unit produces a corrected sensed temperature by subtracting a constant correction amount from the sensed temperature sensed by the temperature-sensing unit; controls the black display voltage, which is a maximum voltage to be applied to the liquid crystal layer, based on the corrected sensed temperature if and when the sensed temperature being sensed by the temperature-sensing unit is stable; and controls the black display voltage based on the sensed temperature being sensed by the temperature-sensing unit until elapsing a predetermined length of time from power on, before being stable;
wherein the control unit further executes control so that:
the black display voltage is decreased with increase of the corrected temperature in accordance with a curve of an optimal black display voltage, if and when the corrected sensed temperature is above a first predetermined temperature;
the black display voltage is kept constant if and when the corrected sensed temperature is at or below the first predetermined temperature and at a same time above a second predetermined temperature; and
the black display voltage is raised, if and when the corrected sensed temperature is at or below the second predetermined temperature, so as not to exceed the optimal black display voltage.
14. The liquid crystal display device according to claim 13 , wherein the first predetermined temperature is around 35° C. or around 40° C.
15. The liquid crystal display device according to claim 13 , wherein the constant correction amount is around 10° C. or around 20° C.
16. The liquid crystal display device according to claim 13 , wherein the second predetermined temperature is around 20° C. or around 35° C.
17. The liquid crystal display device according to claim 13 , wherein the temperature-sensing unit is mounted on a printed wiring board on which the control unit for the OCB mode liquid crystal panel is mounted.