TWI420481B - Display device and brightness adjusting method - Google Patents

Description

Display device and brightness adjustment method

The present invention relates to a display device and a brightness adjustment method, and in particular, to a display device and a brightness adjustment method capable of improving the brightness unevenness caused by the black insertion technique.

Liquid crystal displays (LCDs) have gradually replaced traditional cathode ray tube displays (CRTs) and become mainstream displays. The display principle of the liquid crystal display utilizes a voltage to control the deflection angle of the liquid crystal molecules, so that the light emitted by the backlight passes through the liquid crystal molecules to generate different gray levels through different deflection angles.

In addition to the different principles of illumination, the driving methods of liquid crystal displays and cathode ray tube displays are also different. Conventional cathode ray tubes are of the impulse type driving method, and liquid crystal displays are of the hold type driving method. Due to different driving methods, liquid crystal displays are more prone to dynamic blur than cathode ray tube displays when playing back motion pictures.

In the prior art, the Simulated Pulse Driving method is commonly used to solve the dynamic image sticking problem of liquid crystal displays. Referring to FIG. 1, FIG. 1 is a schematic diagram showing a prior art analog pulse driving method. As shown in FIG. 1, the horizontal axis is time t and the vertical axis is the voltage V of the source input of the driving IC. When the analog pulse driving method is not used, the source driving signal 1 maintains a voltage for the first time T1, that is, the driving IC The source inputs a voltage during the first time T1. On the other hand, when the analog pulse driving method is used, the source is input in the second time T2, and the remaining time T3 is input as black data, and therefore, the actual picture data input time is only the second time T2. Since the method is closer to the pulse driving method used in the cathode ray tube than the driving method of the original liquid crystal display, the method can effectively improve the dynamic image quality to avoid the condition of dynamic image sticking.

However, the analog pulse driving method causes a problem of uneven brightness of the liquid crystal panel. Please refer to FIG. 2 , which is a schematic diagram of a prior art liquid crystal display panel. As shown in FIG. 2, the liquid crystal display panel 2 includes scan lines G1 G G480 sequentially arranged on the panel. Please note that for the sake of simplicity of the drawing, FIG. 2 only shows a plurality of scanning lines to represent all the scanning lines, and the distance between each scanning line and the adjacent scanning lines is substantially the same. The screen data can be sequentially scanned from the scan line G1 to the scan line G480, and when the data signal is scanned to the scan line G360, the black information number can be scanned from the scan line G1.

In the prior art, the liquid crystal display panel 2 is also provided with a blanking area, that is, an area represented by G481 to G525 in FIG. After scanning the data signal to the scanning line G480, the data signal can enter the blanking area, and sequentially scan from the scanning line G481 to the scanning line G525 and then back to the scanning line G1 for re-scanning. Since the occlusion area is not a physical display area, the driver IC does not perform polarity and data conversion (ie, stops inputting data signals) when scanning to the occlusion area, so the driver IC can have a longer charging time. And a larger thrust to input the black information number, which will cause the human eye to feel that this area (G122~G163) is blacker than other areas.

In summary, the analog pulse method can improve the residual image of the liquid crystal display. Phenomenon, however, this method also causes the disadvantage of uneven brightness of the overall picture.

Accordingly, it is an object of the present invention to provide a display device which can improve the problem of uneven brightness of a screen caused by an analog pulse driving method.

According to a specific embodiment, the display device of the present invention comprises N liquid crystal cells, a clock generator and a control module, wherein the control module electrically connects the liquid crystal cells and the clock generator. The clock generator can generate N trigger signals and M blanking signals in one picture period, where M and N are natural numbers.

In this embodiment, the control module can receive N trigger signals, and when receiving one of the N trigger signals, the control module can selectively input the first black insertion signal to the N liquid crystal units. One of them. In addition, the control module can also receive M occlusion signals, and when receiving one of the M black insertion signals, the control module can input the second black insertion signal to one of the N liquid crystal display units. Please note that the first black signal is different from the second black signal.

Another aspect of the present invention is to provide a brightness adjustment method which can be used to solve the problem of uneven brightness of a picture caused by an analog pulse driving method of a liquid crystal display.

According to a specific embodiment, the brightness adjustment method of the present invention can be applied to a display device, which can include N liquid crystal cells, a clock generator, and a control module, wherein the control module electrically connects the liquid crystal cells with time. Pulse generator. The clock generator can generate N in one picture period Trigger signals and M obscuration signals, where M and N are natural numbers.

In this embodiment, the brightness adjustment method may include the following steps: the control module receives one of the N trigger signals, and selectively inputs the first black insertion signal to the N liquid crystal units according to the trigger signal. And the control module receives one of the M blanking signals, and inputs the second black input signal to one of the N liquid crystal displays according to the blanking signal. The first black signal is different from the second black signal.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

Referring to FIG. 3A and FIG. 3B together, FIG. 3A is a functional block diagram of a display device 3 according to an embodiment of the present invention, and FIG. 3B is a view showing the appearance of the display device 3 of FIG. 3A. schematic diagram. As shown in FIG. 3A, the display device 3 includes N liquid crystal cells 30, a clock generator 32, and a control module 34. The control module 34 can be electrically connected to the clock generator 32 and the liquid crystal cells 30.

In this embodiment, the clock generator 32 sequentially generates N trigger signals and M mask signals in a frame period, wherein M and N are natural numbers. Please note that in practice, M and N may be based on the needs of the user or designer and are not limited to the specific embodiments listed in this specification. For example, N can be set to 480 and M can be set to 45. Therefore, the display designed with this parameter has 480 scanning lines, and the 481th to 525th scanning lines are the blanking areas. Please note that the obscuring area in practice is not the physical display area of the display device 3, but A virtual area that meets the design requirements. As shown in Fig. 3B, the display device 3 has scanning lines G1' to G480' and G481' to G525', wherein the scanning lines G1' to G480' are display areas and the scanning lines G481' to G525' are masking areas. The control module 34 can scan the display area by the data signal according to the trigger signals generated by the clock generator 32, that is, the display device 3 can scan from the scan line G1' to G480'. Moreover, at the same time, when the control module 34 receives the obscuration signal, it stops inputting the data signal. The N liquid crystal cells 30 can respectively correspond to the scanning lines of the display area. In other words, in the practice, the display device 3 sequentially scans the scanning lines G1 ′ to G480 ′ to sequentially control the liquid crystal molecules included in each liquid crystal unit 30 . The deflection (not shown). Please note that for the sake of simplicity of the drawing, FIG. 3B only shows a plurality of scanning lines to represent all the scanning lines.

In order to improve the image sticking phenomenon of the display device 3, when the display device 3 scans the data line to the 360th scan line (ie, G360'), the black signal is scanned from the first (G1') scan line. . The time at which the black insertion signal starts scanning may be determined according to the needs of the user or the designer. For example, the designer can design a black signal scanning when the data signal is scanned to the 240th scanning line.

In the specific embodiment, the picture period refers to the time taken by the clock generator 32 to generate N trigger signals and M mask signals, and one frame period can present a frame. Please refer to FIG. 3C. FIG. 3C is a detailed schematic diagram of the display device 3 of FIG. 3A. As shown in Figure III C As shown, the control module 34 can further include a source driver circuit 340, a gate driver circuit 342, and a timing controller 344. The trigger signal and the blanking signal sequentially generated by the clock generator 32 can be received by the control module 34. When the control module 34 receives the trigger signal, the timing controller 344 can control the gate driving circuit 342 to select the liquid crystal according to the trigger signal. One of the units 30 is input with a gate voltage.

According to an embodiment, if the clock generator 32 generates the first trigger signal in a picture period, the timing controller 344 controls the gate driving circuit 342 to the first liquid crystal unit 30 according to the first trigger signal ( In the present embodiment, the first liquid crystal cell 30 corresponds to the input gate voltage of the scan line G1'). In other words, when the first liquid crystal cell 30 receives the gate voltage, the transistor of the liquid crystal cell is in an on state. In addition, the timing controller 344 can also control the source driving circuit 340 to input the first source signal to the liquid crystal unit according to the first trigger signal. The gate voltage and the first source voltage may constitute a first black insertion signal in this embodiment.

In addition, in the specific embodiment, when the timing controller 344 receives the blanking signal generated by the clock generator 32, the timing controller 344 can control the gate driving circuit 342 to input the gate to one of the liquid crystal cells 30. The voltage, and the source driving circuit 340 can be controlled to input a second source voltage to the liquid crystal cell 30. In practice, the gate voltage and the second source voltage can constitute a second black insertion signal.

In summary, when the pulse generator generates the trigger signal, the timing controller can control the source driving circuit and the gate driving circuit to generate and input one of the first black insertion signals to the liquid crystal unit. In addition, the current generator When the signal is blanked, the timing controller can control the source driving circuit and the gate driving circuit to generate and input the second black signal to one of the liquid crystal cells, wherein the first black signal is different from the second black input. Signal. For example, when the display device scans the 360th scan line in the display area with the data signal, the control module inputs the first black insertion signal from the first scan line and scans down with the first black insertion signal. Moreover, when the current generator generates the obscuration signal, the control module replaces the first black insertion signal with the second black insertion signal to continue scanning. When the current generator generates the last blanking signal and sequentially generates the trigger signal to rescan the display device, the control module replaces the second black input signal with the first black input signal to continue scanning.

Since the driver IC does not perform polarity or data conversion when the clock generator generates the blanking signal, the charging time and the thrust ratio for providing the black signal are provided in the section where the clock generator generates the blanking signal. The clock generator generates more trigger signals. In the specific embodiment, if black insertion is performed by only one type of black insertion signal, for example, the first black insertion signal, the area between the 122nd to 163th scanning lines may have a darker color. However, in this embodiment, the first black insertion signal is replaced by the second black insertion signal in this interval, which can solve the problem of uneven brightness of the display device.

According to a specific embodiment, the second source voltage included in the second black insertion signal is smaller than the first source voltage included in the first black insertion signal, and therefore, the clock generator generates a section of the blanking signal. In the middle, the driver IC does not provide excessive charging time and the thrust is inserted into the black signal to cause a portion of the display device to have a darker color (i.e., lower brightness). Please note that the ratio of the second source voltage to the first source voltage in practice can be determined according to the needs of the user or the designer. Generally, the design is generally divided by the naked eye. It is not possible to discriminate the brightness unevenness of the entire display device.

In the previous embodiment, the black voltage of the black signal is directly controlled by the source voltage. However, according to another embodiment, the control module can control the output time of the first black input signal and the second black input signal to adjust the black signal. brightness. In this embodiment, the gate voltage included in the first black insertion signal corresponds to the first output time. In other words, when the control module outputs the first black insertion signal, the timing controller generates the first activation time according to the trigger signal. The first output enable signal, the gate drive circuit can continuously output the gate voltage during the first output time according to the first enable time. In addition, the gate voltage included in the second black insertion signal corresponds to the second output time. The second output time is less than the first output time. Therefore, in the section where the clock generator generates the blanking signal, although the driving IC provides more charging time and thrust to the second black insertion signal, the second black insertion signal duration is shorter than the first black insertion signal, The overall black insertion effect is similar. Similarly, the ratio of the second output time to the first output time in practice may be determined according to the needs of the user or the designer. Generally, the design is substantially indistinguishable from the brightness unevenness of the overall display device. Just fine.

In practice, the brightness of the first black insertion signal and the second black insertion signal are simultaneously affected by the source voltage and the input time. Therefore, according to another specific embodiment, the control module can control the first black insertion signal. The product value obtained by multiplying the source voltage by the first output time corresponding to the gate voltage thereof is substantially equal to the second source voltage of the second black insertion signal multiplied by the second output time corresponding to the gate voltage thereof. Product value. The product values of the source voltages of the first black insertion signal and the second black insertion signal and the gate voltage input time are substantially equal, so that the brightness of the two displays on the display device is large. Physically the same.

Referring to FIG. 4, FIG. 4 is a flow chart showing the steps of the brightness adjustment method according to an embodiment of the present invention. The brightness adjustment method of the specific embodiment can be used for the display device of the above specific embodiment, and, as described in the above specific embodiments, the display device can include N liquid crystal cells, a clock generator, and a control module. Please note that the display device and its internal units have been disclosed in the above specific embodiments, and thus will not be described again.

As shown in FIG. 4, the brightness adjustment method of this embodiment includes the following steps. In step S40, the control module receives one of the N trigger signals generated by the clock generator, and selectively inserts the first black insertion signal into one of the N liquid crystal cells according to the received trigger signal. In addition, in step S42, the control module receives one of the M occlusion signals generated by the clock generator, and inputs the second black insertion signal to the N liquid crystal units according to the received occlusion signal. One. Please note that the first black insertion signal is different from the second black insertion signal.

Since the clock generator sequentially generates N trigger signals and M mask signals, the sequence of steps in this embodiment is followed by step S42 following step S40. In addition, after generating the M occlusion signals, the clock generator can sequentially generate N trigger signals and M occlusion signals, that is, generate N trigger signals and M occlusion signals in the next frame period. Causes the display device to display the next frame of the picture. As described above, according to another embodiment, the step S40 and the step S42 of the brightness adjusting method of the present invention may be alternately performed to continuously adjust the brightness of the screen.

In the brightness adjustment method of the specific embodiment, the control module can control the first The product of the black signal and the source voltage of the second black signal and the gate voltage output time, or the multiplication of the two are substantially equal to improve the brightness unevenness of the picture. Regarding the control when the black signal is generated by the clock generator to generate different signals (trigger signals or blanking signals), the foregoing specific embodiments have been fully disclosed, and thus will not be further described herein.

Referring to FIG. 5, FIG. 5 is a flow chart showing the steps of a brightness adjustment method according to another embodiment of the present invention. As shown in FIG. 5, the brightness adjustment method of this embodiment includes the following steps. In step S50, the control module receives one of the N trigger signals, inputs a data signal to one of the N liquid crystal cells according to the received trigger signal, and selectively inserts the first black insertion signal to the N liquid crystals. One of the other of the units. In step S52, the control module receives one of the M occlusion signals, stops inputting the data signal according to the received occlusion signal, and inputs the second black insertion signal to one of the N liquid crystal cells.

In this embodiment, the control module can sequentially input the data signal to the liquid crystal unit according to the trigger signal generated by the clock generator to display the screen, and when one of the trigger signals is generated, the control module inputs the liquid crystal unit. Insert a black signal. In addition, when the clock generator generates the obscuration signal, the control module has input to the last liquid crystal unit and stops inputting the data signal, and the control module replaces the first black input signal with the second black input signal to the liquid crystal unit. By the difference between the second black insertion signal and the first black insertion signal, the display device can adjust the black degree of the black signal inserted in the picture to improve the brightness unevenness of the picture.

Display device and brightness provided by the present invention compared to prior art The adjustment method is to adjust the black degree of the black signal when the driver IC does not perform polarity conversion and data conversion, so as to improve the brightness unevenness caused by the analog pulse driving method. By adjusting the source voltage, the gate voltage input time, or the product of the two, the black signal can be adjusted, so that the original driver IC adjusts the darker color region caused by the input of the black signal with more thrust and charging time. Blackness to improve the uneven brightness of the screen.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed. Therefore, the scope of the patented scope of the invention should be construed as broadly construed in the

1‧‧ ‧ gate drive signal

T1‧‧‧ first time

T2‧‧‧ second time

T3‧‧‧ remaining time

V‧‧‧ voltage

t‧‧‧Time

2‧‧‧LCD panel

G1~G480‧‧‧ scan line

G481~G525‧‧‧ scan line

3‧‧‧Display device

30‧‧‧Liquid Crystal Unit

32‧‧‧ Clock Generator

34‧‧‧Control Module

G1'~G525'‧‧‧ scan line

340‧‧‧Source drive circuit

342‧‧‧ gate drive circuit

344‧‧‧Sequence Controller

S40~S42‧‧‧ Process steps

S50~S52‧‧‧ Process steps

FIG. 1 is a schematic diagram showing a prior art analog pulse driving method.

2 is a schematic view showing a liquid crystal display panel of the prior art.

Figure 3A is a functional block diagram of a display device in accordance with an embodiment of the present invention.

FIG. 3B is a schematic diagram showing the appearance of the display device of FIG. 3A.

Figure 3C is a detailed schematic view of the display device of Figure 3A.

4 is a flow chart showing the steps of a brightness adjustment method according to an embodiment of the present invention.

FIG. 5 is a flow chart showing the steps of a brightness adjustment method according to another embodiment of the present invention.

3‧‧‧Display device

30‧‧‧Liquid Crystal Unit

32‧‧‧ Clock Generator

34‧‧‧Control Module

340‧‧‧Source drive circuit

342‧‧‧ gate drive circuit

344‧‧‧Sequence Controller

Claims (14)

A display device comprising: N liquid crystal cells; a clock generator, sequentially generating N trigger signals and M blanking signals in a frame period, wherein M And N are both natural numbers; and a control module electrically connected to the clock generator and the N liquid crystal units, and when receiving one of the N trigger signals, selectively inputting a first Inserting a black signal to one of the N liquid crystal cells; wherein, when the control module receives one of the M blanking signals, the second black signal is input to the N liquid crystals One of the liquid crystal cells of the unit, the first black insertion signal is different from the second black insertion signal, the first black insertion signal includes the gate voltage and a first source voltage, and the second black insertion signal includes the gate a gate voltage and a second source voltage, the control module includes: a source driving circuit electrically connected to the N liquid crystal cells; a gate driving circuit electrically connected to The N liquid crystal cells; and a moment a timing controller electrically connected to the clock generator, the source driving circuit and the gate driving circuit, and when receiving the trigger signal, controlling the gate driving circuit to selectively output the gate voltage Up to one of the N liquid crystal cells, and simultaneously controlling the source driving circuit to input the first source voltage to the liquid crystal cell; When the timing controller receives the blanking signal, controlling the gate driving circuit to output the gate voltage to one of the N liquid crystal cells, and controlling the source driving circuit to input the second source The gate voltage of the first black insertion signal corresponds to a first output time, and the voltage of the second black insertion signal corresponds to a second output time, the second The output time is less than the first output time. A display device comprising: N liquid crystal cells; a clock generator, sequentially generating N trigger signals and M blanking signals in a frame period, wherein M And N are both natural numbers; and a control module electrically connected to the clock generator and the N liquid crystal units, and when receiving one of the N trigger signals, selectively inputting a first Inserting a black signal to one of the N liquid crystal cells; wherein, when the control module receives one of the M blanking signals, the second black signal is input to the N liquid crystals One of the liquid crystal cells of the unit, the first black insertion signal is different from the second black insertion signal, the first black insertion signal includes the gate voltage and a first source voltage, and the second black insertion signal includes the gate a gate voltage and a second source voltage, the control module includes: a source driving circuit electrically connected to the N liquid crystal cells; a gate driving circuit electrically connected to The N liquid crystal cells; a timing controller electrically connected to the clock generator, the source driving circuit and the gate driving circuit, and when receiving the trigger signal, controlling the gate driving circuit to selectively output the gate And a voltage is applied to one of the N liquid crystal cells, and the source driving circuit is controlled to input the first source voltage to the liquid crystal cell; wherein when the timing controller receives the blanking signal, the gate is controlled The pole driving circuit outputs the gate voltage to one of the N liquid crystal cells, and controls the source driving circuit to input the second source voltage to the liquid crystal cell, the gate voltage of the first black insertion signal Corresponding to a first output time, the gate voltage of the second black insertion signal corresponds to a second output time, and the value of the first output time multiplied by the first source voltage is equivalent to the second output The time is multiplied by the value of the second source voltage. The display device of claim 2, wherein the second source voltage is less than the first source voltage. The display device of claim 2, wherein the second output time is less than the first output time. The display device of claim 1, wherein when the timing controller receives the trigger signal, generating a first output enable signal having a first enable period The gate driving circuit continuously outputs the gate voltage at the first output time according to the first enable period, and when the timing controller receives the blanking signal, generates a second Can time (enable a second output enable signal of the period, the gate drive circuit continuously outputting the gate voltage for the second output time according to the second enable time. The display device of claim 2, wherein when the control module receives the trigger signal, inputting a data signal to one of the N liquid crystal units, when the control module receives the When the signal is blocked, stop inputting the data signal. The display device of claim 1, wherein when the control module receives the trigger signal, inputting a data signal to one of the N liquid crystal units, when the control module receives the When the signal is blocked, stop inputting the data signal. A brightness adjustment method for a display device, the display device comprising N liquid crystal cells, a clock generator and a control module, the control module being electrically connected to the clock generator and the N In the liquid crystal unit, the clock generator sequentially generates N trigger signals and M blanking signals in a frame period, wherein M and N are natural numbers, and the method includes the following steps: The control module receives one of the N trigger signals, selectively inputs a first black input signal to one of the N liquid crystal units, and the control module receives the M masks. One of the signals obscures the signal, and inputs a second black signal to one of the N liquid crystal cells, the first black signal is different from the second black signal; wherein the control module includes a source Pole drive circuit And a timing controller, the source driving circuit and the gate driving circuit are electrically connected to the N liquid crystal cells, and the timing controller is electrically connected to the clock generator, the source driving circuit and the gate driving The first black insertion signal includes the gate voltage and a first source voltage, and the second black insertion signal includes the gate voltage and a second source voltage, and the step of receiving the trigger signal includes The following steps: the timing controller receives the trigger signal, and controls the gate driving circuit to selectively output the gate voltage to one of the N liquid crystal cells, and simultaneously control the source driving circuit to input the first source The step of receiving the blanking signal includes the following steps: the timing controller receives the blanking signal, and controls the gate driving circuit to output the gate voltage to one of the N liquid crystal cells a liquid crystal cell that simultaneously controls the source driving circuit to input the second source voltage to the liquid crystal cell; wherein the gate voltage of the first black insertion signal corresponds to a first output time, the second insertion The gate signal of a second voltage corresponding to the output time, output time of the second output smaller than the first time. A brightness adjustment method for a display device, the display device comprising N liquid crystal cells, a clock generator and a control module, the control module being electrically connected to the clock generator and the N In the liquid crystal unit, the clock generator sequentially generates N trigger signals and M blanking signals in a frame period, wherein M and N are natural numbers, and the method includes the following steps: The control module receives one of the N trigger signals and selectively inputs a first black input signal to one of the N liquid crystal units. And the control module receives one of the M occlusion signals to mask the signal, and inputs a second black insertion signal to one of the N liquid crystal cells, the first black insertion signal is different from the a second black insertion signal; wherein the control module comprises a source driving circuit, a gate driving circuit and a timing controller, wherein the source driving circuit and the gate driving circuit are electrically connected to the N liquid crystal units, The timing controller is electrically connected to the clock generator, the source driving circuit and the gate driving circuit, the first black insertion signal includes the gate voltage and a first source voltage, and the second black insertion signal The step of receiving the trigger signal includes the following steps: the timing controller receives the trigger signal, and controls the gate driving circuit to selectively output the gate voltage to the gate voltage a liquid crystal cell of one of the N liquid crystal cells, and simultaneously controlling the source driving circuit to input the first source voltage to the liquid crystal cell; in the step of receiving the blanking signal, the method includes the following steps: receiving the timing controller The masking signal controls the gate driving circuit to output the gate voltage to one of the N liquid crystal cells, and controls the source driving circuit to input the second source voltage to the liquid crystal cell; wherein the The gate voltage of a black signal corresponds to a first output time, the gate voltage of the second black signal corresponds to a second output time, and the first output time is multiplied by the first source The value of the voltage is equivalent to the value of the second output time multiplied by the second source voltage. The brightness adjustment method of claim 9, wherein the second source voltage is less than the first source voltage. The brightness adjustment method of claim 9, wherein the second output time is less than the first output time. The method for adjusting the brightness according to claim 8, wherein the step of receiving the trigger signal further includes the following steps: the timing controller receives the trigger signal to generate a first output having a first enable time And the gate driving circuit continuously outputs the gate voltage according to the first enable time according to the first enable time; and in the step of receiving the blanking signal, further comprising the following steps: the timing controller Receiving the occlusion signal to generate a second output enable signal having a second enable time; and the gate drive circuit continuously outputting the gate voltage at the second output time according to the second enable time. In the step of receiving the trigger signal, the method further includes the following steps: the control module receives the trigger signal, and inputs a data signal to one of the N liquid crystal units. The liquid crystal unit further includes the following steps in the step of receiving the obscuration signal: the control module receives the obscuration signal and stops inputting the data signal. In the step of receiving the trigger signal, the method further includes the following steps: the control module receives the trigger signal, and inputs a data signal to one of the N liquid crystal units. The liquid crystal unit; in the step of receiving the blanking signal, further comprising the following steps: The control module receives the obscuration signal and stops inputting the data signal.