The present disclosure relates to display apparatus, driving module thereof, voltage control circuit and voltage control method, and more particularly to display apparatus, driving module thereof, voltage control circuit and voltage control method for compensating operating voltages of a gate driver array.
The glass substrate 102 has a display area 112 and two gate driver on arrays (GOAs) 114 and 116. The display area 112 includes a plurality of gate lines 118 and a plurality of source lines 120, which are arranged to each other in a sequential and intersectional manner. A liquid crystal unit 122, served as a pixel cell, is disposed at each intersectional point of the gate lines 118 and the source lines 120; and accordingly the liquid crystal units 122 are arranged in a matrix manner. In addition, each liquid crystal unit 122 is coupled to the corresponding gate line 118 and source line 120 via a thin film transistor 124.
The gate driver on arrays 114 and 116 are coupled to the display area 112 via the gate lines 118 and configured to generate a plurality of scanning signals (not shown) according to an operating voltage. The scanning signals are transmitted to the gate lines 118 and thereby turning on the thin film transistors 124 coupled to the gate lines 118. However, when the liquid crystal display apparatus 100 is operated in a relatively-low temperature, the output currents of the thin film transistors 124 may drop substantially and consequently the liquid crystal display apparatus 100 may not be able to display images normally.
Specifically, the aforementioned issue is getting more serious if the gate driver on arrays 114 and 116 are directly manufactured on the glass substrate 102 by the GOA technical rather than employing an external integrated driving circuit.
In order to solve the above issue, conventionally the printed circuit board 104 is disposed with a temperature sensor 130 thereon. Thus, The gate driver on arrays 114 and 116 can have the potential levels of the operating voltages thereof raised up if the temperature sensor 130 senses that the environmental temperature is lower than a threshold degree, and consequentially the liquid crystal display apparatus 100 still can display images normally in a relatively-low temperature.
The present disclosure provides voltage control circuit and voltage control method for compensating the operating voltage of the gate driver array of the display apparatus. Thus, the display apparatus can display images normally in different temperatures.
The present disclosure further provides a driving module of a display apparatus. The driving module is capable of driving the display apparatus to display images normally in different temperatures.
The present disclosure still provides a display apparatus capable of displaying images normally in different temperatures.
An embodiment of the disclosure provides a voltage control circuit adapted to be used to control a first clock signal received by a gate driver array of a display apparatus. The voltage control circuit includes a gate trigger pulse generator unit and a controller. The gate trigger pulse generator unit is configured to receive a reference voltage and one of a plurality of driving signals outputted from the gate driver array and accordingly generate a gate trigger pulse, wherein a pulse width of the gate trigger pulse is controlled by the gate trigger pulse generator unit according to a potential-level relationship between the received driving signal and the reference voltage. The controller, coupled to the gate trigger pulse generator unit, is configured to receive the gate trigger pulse and control a potential difference of a pulse level of the first clock signal according to the pulse width of the gate trigger pulse.
Another embodiment of the disclosure provides a driving module of a display apparatus. The display apparatus includes a plurality of pixel rows arranged in a sequence and each pixel row includes a plurality of pixels. The driving module includes a gate driver array, a voltage control circuit and an operating voltage generator circuit. The gate driver array is coupled to the pixel rows and configured to receive a first clock signal and output a plurality of driving signals in a sequence to drive the pixel rows, respectively. The voltage control circuit is coupled to the gate driver array and configured to control a potential difference of a pulse level of the first clock signal. The voltage control circuit includes a gate trigger pulse generator unit and a controller. The gate trigger pulse generator unit is configured to receive a reference voltage and one of a plurality of driving signals outputted from the gate driver array and accordingly generate a gate trigger pulse, wherein a pulse width of the gate trigger pulse is controlled by the gate trigger pulse generator unit according to a potential-level relationship between the received driving signal and the reference voltage. The controller is coupled to the gate trigger pulse generator unit and configured to receive the gate trigger pulse and output a control voltage according to the pulse width of the gate trigger pulse thereby controlling the potential difference of a pulse level of the first clock signal. The operating voltage generator circuit is coupled to the gate driver array and configured to provide the first clock signal and adjust the first clock signal according to the control signal.
Still another embodiment of the disclosure provides a display apparatus, which includes a substrate, a plurality of gate lines, a gate driver array, an operating voltage generator circuit and a voltage control circuit. The substrate includes a display area. The display area includes a plurality of pixel rows arranged in a sequence. Each pixel row includes a plurality of pixels. The gate lines are respectively coupled to the pixels of the respective pixel rows. The gate driver array is configured to receive a first clock signal. The gate driver array includes a plurality of series-coupled driving shift registers and at least one dummy shift register. The series-coupled driving shift registers are coupled to the gate lines respectively and configured to sequentially output a first driving signal to the respective gate lines according to the first clock signal and thereby turning on the pixels coupled to the gate lines. The dummy shift register is coupled to the last-stage driving shift register of the driving shift registers and configured to receive the first driving signal from the last-stage driving shift register and generate a second driving signal. The operating voltage generator circuit is coupled to the gate driver array and configured to provide the first clock signal. The voltage control circuit, coupled to the dummy shift register and the operating voltage generator circuit, is configured to control a potential difference of a pulse level of the first clock signal according to a potential-level relationship between a reference voltage and either one of the first driving signals or one of the second driving signals.
Yet another embodiment of the disclosure provides a voltage control method adapted to be used to control a first clock signal of a gate driver array of a display apparatus. The voltage control method includes steps of: receiving a driving signal outputted from the gate driver array and generating a gate trigger pulse according to the received driving signal; controlling a pulse width of the gate trigger pulse according to a potential-level relationship between the driving signal and a reference voltage; and controlling a potential difference of a pulse level of the first clock signal according to the pulse width of the gate trigger pulse.
In summary, by monitoring the driving signals outputted from the gate driver array of the display apparatus, the present invention can dynamically adjust the potential difference of the pulse level of the first clock signal in time. In addition, by directly disposing the voltage control circuit on either the glass substrate or the printed circuit board, the present invention can have lower hardware cost.
The present disclosure will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
The present disclosure will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this disclosure are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.
The display area 204 has a plurality of pixel rows PR(1), PR(2), . . . , PR(K) arranged in a sequence; where K is a positive integer. In addition, the pixel rows PR(1), PR(2), . . . , PR(K) each are corresponding to at least one gate line. In this embodiment, the pixel rows PR(1), PR(2), . . . , PR(K) are corresponding to the gate lines G1, G2, . . . , GK, respectively. The pixel rows PR(1), PR(2), . . . , PR(K) each include a plurality of pixels (herein only two exemplary pixels 212 and 214 are shown) arranged in a sequence. The gate lines G1, G2, . . . , GK each are coupled to all the pixels in the respective pixel row.
The driving module 206 includes a gate driver array 222, a voltage control circuit 226 and an operating voltage generator circuit 228; wherein the gate driver array 222 is specifically called a gate driver on array (GOA) if being disposed on the substrate 202. In this embodiment, the operating voltage generator circuit 228 is configured to output a first clock signal VCK and/or a start signal VST; wherein the functions of the two signals VCK and VST will be described in detail later. In addition, the operating voltage generator circuit 228 is further configured to control the potential difference of the pulse level of the first clock signal VCK and/or the start signal VST according to a control voltage VG outputted from the voltage control circuit 226.
Please refer back to
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The transistor 404 is configured to have the first end thereof for receiving the first clock signal VCK, the second end thereof coupled to the gate line Gn and the first end of the transistor 408. The transistors 406 and 408 each are configured to have the gate end thereof coupled to the next-stage gate lines Gn+1 and the second end thereof grounded. In an embodiment, the transistors 402, 404, 406 and 408 each is implemented by an NMOS transistor; and the present invention is not limited thereto. It is to be noted that the driving signal on the gate line Gn is generated based on the first clock signal VCK and either the signal on the previous-stage gate line Gn−1 or the start signal VST; accordingly, each shift register can have a specific output waveform by adjusting the potential differences of the pulse levels of the first clock signal VCK and the start signal VST.
Within the period between time points 5t1 and 5t2, the transistor 402 is turned off by the logic-low potential on the previous-stage gate line Gn−1; however, the transistor 404 is still turned-on due to the node Qn is maintained at the first potential. Accordingly, the node Qn is further charged to have a second potential by the current, derived from the logic-high first clock signal VCK, flowing through the turned-on transistor 404 within the same period. Thus, via the turned-on transistor 404, the second end of the transistor 404 is switched to have the logic-high potential by the logic-high first clock signal VCK so as to result in the first driving signal S1 on the gate line Gn. Within the same period between time points 5t1 and 5t2, the transistors 406 and 408 are still turned off by the logic-low potential on the next-stage gate line Gn+1.
After the time point 5t2, the transistors 406 and 408 both are turned on by the logic-high potential on the previous-stage gate line Gn+1; accordingly, the node Dn and the second end of the transistor 404 are discharged by the turned-on transistors 406 and 408, respectively. Eventually, the transistor 404 will be turned off and the gate line Gn is switched to have a logic-low potential thereon and thereby completing one work cycle of the first driving signal S1.
In one embodiment, the gate trigger pulse generator unit 602 may be implemented by a comparator 606 as illustrated in
As shown in
Please refer to
Specifically, the controller 604, when detecting an enabled start signal VST, is configured to calculate the pulse width of the gate trigger pulse GOA_PLS by using the second clock signal HVCK. In other words, by calculating the number of the second clock signal HVCK within the working period of the gate trigger pulse GOA_PLS, the controller 604 can calculate the pulse width of the gate trigger pulse GOA_PLS, and accordingly determine the potential levels of the start signal VST, the first clock signal VCK and/or the operating voltage VGH. Briefly, by dynamically modulating the potential levels of the start signal VST, the first clock signal VCK and/or the operating voltage VGH within each frame time, the gate trigger pulse GOA_PLS in this frame time can be configured to have a specific pulse width; wherein the pulse width of the gate trigger pulse GOA_PLS is associated with a relationship between the first driving signal S1/the second driving signal S2 and the reference voltage Vref.
When an enabled start signal is detected, the voltage control method starts to count the number of the second clock signals HVCK of the display apparatus until a falling edge of the gate trigger pulse GOA_PLS is detected, so as to determine the pulse width of the gate trigger pulse GOA_PLS (step 1008). Thus, the method can control the potential difference of the pulse level of the first clock signal VCK according to the length of the gate trigger pulse GOA_PLS.
After the pulse width of the gate trigger pulse GOA_PLS is calculated, the voltage control method determines that whether the pulse width of the gate trigger pulse GOA_PLS is smaller than a first threshold value or greater than a second threshold value (step 1010). If the display apparatus is operated in a relatively-low-temperature environment which is indicated by that the pulse width of the gate trigger pulse GOA_PLS is smaller than the first threshold value, the voltage control method increases the potential difference of the pulse level of the first clock signal VCK (step 1012), so as to make the display apparatus still have normal functions in a relatively-low-temperature environment. It is to be noted that the potential difference of the pulse level of the first clock signal VCK may have a multi-segmented modulation with a decreasing of temperature. The method moves to step 1014 after the step 1012 is completed.
In step 1010, alternatively, if the display apparatus is operated in a relatively-high-temperature environment which is indicated by that the pulse width of the gate trigger pulse GOA_PLS is greater than the second threshold value, the voltage control method decreases the potential difference of the pulse level of the first clock signal VCK (step 1014), so as to make the display apparatus still have normal functions in a relatively-high-temperature environment.
In summary, by monitoring the driving signals outputted from the gate driver array of the display apparatus, the present invention can dynamically adjust the potential difference of the pulse level of the first clock signal in time. In addition, by directly disposing the voltage control circuit on either the glass substrate or the printed circuit board, the present invention can have lower hardware cost.
While the disclosure has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the disclosure needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
Number | Date | Country | Kind |
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101140599 | Nov 2012 | TW | national |