Display apparatus having signal delay compensation
View Patent ↗A display apparatus includes a controller which generates control signals and outputs image data, a compensating circuit which receives a portion of the control signals from the controller and generates a compensation signal, a voltage generating circuit which converts an input voltage to a driving voltage and increases or decreases a voltage level of the driving voltage in a frame period in response to the compensation signal, a driving part which receives the control signals and the image data from the controller and receives the driving voltage from the voltage generating circuit to generate a panel driving signal, and a display panel which receives the panel driving signal from the driving part to display an image.
1. A display apparatus comprising:
a controller which generates control signals and outputs image data;
a compensating circuit which receives a portion of the control signals from the controller and generates a compensation signal;
a voltage generating circuit which converts an input voltage to a driving voltage and increases or decreases a voltage level of the driving voltage in a frame period in response to the compensation signal;
a driving part which receives the control signals and the image data from the controller and receives the driving voltage from the voltage generating circuit to generate a panel driving signal; and
a display panel which receives the panel driving signal from the driving part to display an image,
wherein the voltage level of the driving voltage non-linearly varies during the frame period.
2. The display apparatus of claim 1 , wherein the driving part comprises:
a gate driver which generates a gate signal based on the driving voltage; and
a data driver which converts the image data to a data voltage.
3. The display apparatus of claim 2 , wherein
the compensation signal comprises a pulse width modulation signal, and
the compensating circuit controls a duty ratio of the pulse width modulation signal and applies the pulse width modulation signal to the voltage generating circuit.
4. The display apparatus of claim 3 , wherein the voltage generating circuit comprises:
an on-voltage generator which generates a gate-on voltage which determines a high level of the gate signal; and
an off-voltage generator which generates a gate-off voltage which determines a low level of the gate signal.
5. The display apparatus of claim 4 , wherein
the display panel comprises first to n-th gate lines arranged in a first direction, and
the voltage generating circuit is disposed adjacent to one of the first to n-th gate lines.
6. The display apparatus of claim 5 , wherein
the first to n-th gate lines are sequentially scanned along the first direction,
the on-voltage generator comprises a first positive voltage generator which non-linearly increases the gate-on voltage from a reference gate-on voltage to a maximum gate-on voltage during the frame period, and
the off-voltage generator comprises a second positive voltage generator which non-linearly decreases the gate-off voltage from a reference gate-off voltage to a minimum gate-off voltage during the frame period.
7. The display apparatus of claim 6 , wherein the first positive voltage generator comprises:
a voltage-increasing part which increases the gate-on voltage from the reference gate-on voltage to the maximum gate-on voltage based on the duty ratio of the pulse width modulation signal; and
a discharging part which discharges the gate-on voltage to the reference gate-on voltage in response to a compensation control signal from the compensating circuit.
8. The display apparatus of claim 6 , wherein the second positive voltage generator comprises:
a voltage-decreasing part which decreases the gate-off voltage from the reference gate-off voltage to the minimum gate-off voltage based on the duty ratio of the pulse width modulation signal; and
a boosting part which boosts the gate-off voltage to the reference gate-off voltage in response to the compensation control signal.
9. The display apparatus of claim 5 , wherein
the first to n-th gate lines are sequentially scanned along a second direction, which is opposite to the first direction,
the on-voltage generator comprises a first negative voltage generator which non-linearly decreases the gate-on voltage from a maximum gate-on voltage to a reference gate-on voltage during the frame period, and
the off-voltage generator comprises a second negative voltage generator which non-linearly increases the gate-off voltage from a minimum gate-off voltage to a reference gate-off voltage during the frame period.
10. The display apparatus of claim 9 , wherein
an electric potential period between the maximum gate-on voltage and the reference gate-on voltage comprises 2 y unit time periods during the frame period, wherein y is an integer equal to or greater than 1,
a difference value between the maximum gate-on voltage and the reference gate-on voltage is α, and
an electric potential difference between adjacent unit electric potential periods is about α/2 y .
11. The display apparatus of claim 9 , wherein
an electric potential period between the reference gate-off voltage and the minimum gate-off voltage comprises 2 y unit-time periods during the frame period, wherein y is an integer equal to or greater than 1,
a difference value between the reference gate-off voltage and the minimum gate-off voltage is β, and
an electric potential difference between adjacent unit electric potential periods is about β/2 y .
12. The display apparatus of claim 4 , wherein
the compensation signal further comprises a compensation control signal which determines a compensation timing of the gate-on voltage and the gate-off voltage, and
the compensation control signal comprises a high period and a low period, which sequentially occur in the frame period.
13. The display apparatus of claim 12 , wherein
the compensating circuit receives a vertical start signal among the control signals to start an operation of the gate driver, and
the high period of the compensation control signal starts in synchronization with a rising timing of the vertical start signal.
14. The display apparatus of claim 13 , wherein
the display panel comprises first to n-th gate lines arranged in a first direction,
the frame period comprises:
a scan period during which the first to n-th gate lines are scanned; and
a blank period disposed between the scan period and a scan period of a next frame, and
the low period is in the blank period.
15. The display apparatus of claim 12 , wherein
each of the gate-on voltage and the gate-off voltage comprises k inflection points and is non-linearly increased or decreased during the frame period, wherein k is an integer equal to or greater than 1,
the frame period is divided into k+1 linear periods, and
a variation in voltage of each of the gate-on voltage and the gate-off voltage is constant in each of the linear periods.
16. The display apparatus of claim 15 , wherein
the gate-on voltage and the gate-off voltage have 2 x unit-time periods on a time axis during the frame period, wherein x is an integer equal to or greater than 1, and
each of the linear periods comprises at least one of the unit-time period.
17. A display apparatus comprising:
a display panel which displays an image using a light;
a switching panel which controls liquid crystal molecules to allow the display panel to operate in a two-dimensional mode or a three-dimensional mode and the image displayed in the display panel to be recognized as a two-dimensional image or a three-dimensional image;
a first driver which drives the display panel;
a second driver which drives the switching panel; and
a controller which controls the first and second drivers, wherein the first driver comprises:
a compensating circuit which receives control signals from the controller and generates a compensation signal;
a voltage generating circuit which converts an input voltage to a driving voltage and increases or decreases a voltage level of the driving voltage in a frame period in response to the compensation signal; and
a panel driving part which receives the control signals and image data from the controller and receives the driving voltage from the voltage generating circuit to generate a panel driving signal,
wherein the voltage level of the driving voltage non-linearly varies during the frame period.
18. The display apparatus of claim 17 , wherein the panel driving part comprises:
a gate driver which generates a gate signal based on the driving voltage; and
a data driver which converts the image data to a data voltage.
19. The display apparatus of claim 18 , wherein
the compensation signal comprises a pulse width modulation signal,
the compensating circuit controls a duty ratio of the pulse width modulation signal and apply the controlled pulse width modulation signal to the voltage generating circuit, and
the voltage generating circuit comprises:
an on-voltage generator which generates a gate-on voltage which determines a high level of the gate signal of the driving voltage; and
an off-voltage generator which generates a gate-off voltage which determines a low level of the gate signal of the driving voltage.
20. The display apparatus of claim 19 , wherein
a width of the frame period in the two-dimensional mode is greater than a width of the frame period in the third-dimensional mode, and
the on-voltage generator non-linearly increases or decreases the gate-on voltage from a first maximum gate-on voltage to a reference gate-on voltage in the two-dimensional mode and non-linearly increases or decreases the gate-on voltage from a second maximum gate-on voltage to the reference gate-on voltage in the three-dimensional mode.
21. The display apparatus of claim 20 , wherein a difference in electric potential between the first maximum gate-on voltage and the reference gate-on voltage is equal to or greater than a difference in electric potential between the second maximum gate-on voltage and the reference gate-on voltage.
22. The display apparatus of 19 , wherein
a width of the frame period in the two-dimensional mode is greater than a width of the frame period in the third-dimensional mode, and
the off-voltage generator non-linearly increases or decreases the gate-off voltage from a first minimum gate-off voltage to a reference gate-off voltage in the two-dimensional mode and non-linearly increases or decreases the gate-off voltage from a second minimum gate-off voltage to the reference gate-off voltage in the three-dimensional mode.
23. The display apparatus of claim 22 , wherein a difference in electric potential between the first minimum gate-off voltage and the reference gate-off voltage is equal to or greater than a difference in electric potential between the second minimum gate-off voltage and the reference gate-off voltage.