Voltage adjustment circuit for common electrode and display apparatus

Disclosed are a voltage adjustment circuit for a common electrode and a display apparatus, which are capable of improving a sensitivity and a precision in an adjustment of a voltage of the common electrode. The voltage adjustment circuit for the common electrode includes a first fixed resistor, a second fixed resistor and a first adjustable resistor and the voltage adjustment circuit for the common electrode further includes an adjustment module, which is connected to an output terminal of the voltage adjustment circuit for the common electrode and an adjustable terminal of the first adjustable resistor, and is configured to cooperate with the first adjustable resistor to adjust a resistance of the voltage adjustment circuit for the common electrode in order to adjust the output voltage of the common electrode.

TECHNICAL FIELD OF THE DISCLOSURE

The present disclosure relates to the field of display technology, and particularly to a voltage adjustment circuit for a common electrode and a display apparatus.

BACKGROUND

Liquid crystal (LC) panels have been widely used in display products such as cell phones, smart monitors, LC TV sets, personal computers and so on due to their advantages such as small thinness, high brightness, low radiation and so on.

Usually, the LC panels may have different best voltages at their respective common electrodes since big differences exist among equivalent capacitances of the LC panels. Therefore, when designing a driving circuit of the LC panel, researchers would design a driving circuit with an adjustable resistor. By adjusting the adjustable resistor in the driving circuit, it is possible to realize an adjustment of the voltage at the common electrode such that each LC panel can reach its best voltage at the common electrode. Simultaneously, in order to avoid a flicker phenomenon to exist in pictures displayed on the LC panel, the voltage of the common electrode needs to have a high adjustment precision.

The inventor found that existing voltage adjustment circuits for the common electrode have poor sensitivity and precision in the adjustment, and sometimes cannot adjust the voltage of the common electrode to the most suitable voltage, which affects a display effect of the display apparatus.

SUMMARY

A technical problem to be solved by the present disclosure is to provide a voltage adjustment circuit for a common electrode and a display apparatus, which can improve the sensitivity and precision in the adjustment of the voltage of the common electrode.

A first aspect of the present disclosure provides a voltage adjustment circuit for a common electrode, comprising a first fixed resistor, a second fixed resistor and a first adjustable resistor, wherein a first terminal of the first fixed resistor is connected to a first input terminal of the voltage adjustment circuit for the common electrode, a first terminal of the second fixed resistor is connected to a second input terminal of the voltage adjustment circuit for the common electrode, a first terminal of the first adjustable resistor is connected to a second terminal of the first fixed resistor, and a second terminal of the first adjustable resistor is connected to a second terminal of the second fixed resistor, wherein the voltage adjustment circuit for the common electrode further comprises:

an adjustment module, which is connected to an output terminal of the voltage adjustment circuit for the common electrode and an adjustable terminal of the first adjustable resistor, and configured to cooperate with the first adjustable resistor to adjust a resistance of the voltage adjustment circuit for the common electrode in order to adjust an output voltage of the common electrode.

The adjustment module comprises a second adjustable resistor, wherein a first terminal thereof is connected to the adjustable terminal of the first adjustable resistor, a second terminal thereof is connected to a third fixed voltage terminal, and an adjustable terminal thereof is connected to the output terminal of the voltage adjustment circuit for the common electrode.

Alternatively, the first terminal of the adjustment module is connected to the first terminal of the first adjustable resistor, a second terminal of the adjustment module is connected to the second terminal of the first adjustable resistor, the adjustable terminal of the adjustment module and the adjustable terminal of the first adjustable resistor are connected together to the output terminal of the voltage adjustment circuit for the common electrode.

The adjustment module comprises a second adjustable resistor, wherein a first terminal thereof is connected to the first terminal of the adjustable resistor, a second terminal thereof is connected to the second terminal of the first adjustable resistor, and a adjustable terminal thereof and the adjustable terminal of the first adjustable resistor are connected together to the output terminal of the voltage adjustment circuit for the common electrode.

The adjustment module further comprises a third fixed resistor and a fourth fixed resistor;

the first terminal of the second adjustable resistor being connected to the first terminal of the first adjustable resistor comprises that:

the first terminal of the second adjustable resistor is connected to a first terminal of the third fixed resistor, and a second terminal of the third fixed resistor is connected to the first terminal of the first adjustable resistor and the second terminal of the first fixed resistor; and

the second terminal of the second adjustable resistor being connected to the second terminal of the first adjustable resistor comprises that:

the second terminal of the second adjustable resistor is connected to a first terminal of the fourth fixed resistor, and a second terminal of the fourth fixed resistor is connected to the second terminal of the first adjustable resistor and the second terminal of the second fixed resistor.

The voltage adjustment circuit for the common electrode further comprises a first capacitor, wherein a first terminal thereof is connected to the output terminal of the voltage adjustment circuit for the common electrode, and a second terminal thereof is grounded.

The voltage adjustment circuit for the common electrode further comprises a second capacitor, wherein a first terminal thereof is connected to the output terminal of the voltage adjustment circuit for the common electrode, and a second terminal thereof is grounded.

The adjustment module at least further comprises a third adjustable resistor, wherein a first terminal thereof is connected to the first terminal of the second adjustable resistor, a second terminal thereof is connected to the second terminal of the second adjustable resistor, and an adjustable terminal thereof and the adjustable terminal of the second adjustable resistor are connected together to the output terminal of the voltage adjustment circuit for the common electrode.

In the technical solutions of embodiments of the present disclosure, the voltage adjustment circuit for the common electrode has at least two adjustable resistors. The at least two adjustable resistors cooperate to improve the sensitivity and the precision in the adjustment of the output voltage for the common electrode, such that the common electrode has a suitable voltage value to prevent the display apparatus from presenting the flicker phenomenon in the pictures. Further, when one of the adjustable resistors fails due to malfunctions, the other adjustable resistors can still work to remain adjusting the output voltage of the voltage adjustment circuit for the common electrode, which improves an operation reliability of the voltage adjustment circuit for the common electrode.

A second aspect of the disclosure provides a display apparatus comprising a voltage adjustment circuit for a common electrode described in the above.

DETAILED DESCRIPTION

Thereafter, solutions of embodiments of the present disclosure will be described clearly and completely in connection with drawings of the embodiments of the present disclosure, but obviously the described embodiments are only some, but not all of the embodiments of the present disclosure. Any other embodiments obtained by those ordinary skilled in the art based on the embodiments of the present disclosure without inventive labors should fall into a scope sought for protection in the present disclosure.

An embodiment of the present disclosure provides a voltage adjustment circuit for a common electrode, comprising a first fixed resistor, a second fixed resistor and a first adjustable resistor, wherein a first terminal of the first fixed resistor is connected to a first input terminal of the voltage adjustment circuit for the common electrode, a first terminal of the second fixed resistor is connected to a second input terminal of the voltage adjustment circuit for the common electrode, a first terminal of the first adjustable resistor is connected to a second terminal of the first fixed resistor, and a second terminal of the first adjustable resistor is connected to a second terminal of the second fixed resistor.

Further, the voltage adjustment circuit for the common electrode further comprises: an adjustment module which is connected to an output terminal of the voltage adjustment circuit for the common electrode and an adjustable terminal of the first adjustable resistor, and is configured to cooperate with the first adjustable resistor to adjust a resistance of the voltage adjustment circuit for the common electrode in order to adjust an output voltage of the common electrode.

A first manner is as follows, as shown inFIG. 1, there are a first fixed resistor R1, a second fixed resistor R2and a first adjustable resistor VR1. A first terminal of the first fixed resistor R1is connected to a first input terminal Vin1of the voltage adjustment circuit for the common electrode, a first terminal of the second fixed resistor R2is connected to a second input terminal Vin2of the voltage adjustment circuit for the common electrode, a first terminal of the first adjustable resistor VR1is connected to a second terminal of the first fixed resistor R1, a second terminal of the first adjustable resistor V1is connected to a second terminal of the second fixed resistor R2, and an adjustable terminal of the first adjustable resistor VR1is connected to the output terminal Voutof the voltage adjustment circuit for the common electrode.

Further, the voltage adjustment circuit for the common electrode further comprises an adjustment module. At this time, the adjustable terminal of the first adjustable resistor is connected to an output terminal Voutof the voltage adjustment circuit for the common electrode through the adjustment module. The adjustment module cooperates with the first adjustable resistor VR1to adjust the resistance of the voltage adjustment circuit for the common electrode in order to adjust the output voltage of the common electrode. For example, the adjustment module comprises a second adjustable resistor VR2, a first terminal of the second adjustable resistor VR2is connected to the adjustable terminal of the first adjustable resistor VR1, a second terminal of the second adjustable resistor VR2is connected to a third fixed voltage terminal, and an adjustable terminal of the second adjustable resistor VR2is connected to the output terminal Voutof the voltage adjustment circuit for the common electrode. In this manner, the adjustment module adjusts the voltage output from the adjustable terminal of the first adjustable resistor VR1again, which can improve the sensitivity and precision in the adjustment of the voltage adjustment circuit for the common electrode. Of course, a voltage difference between a voltage at the third fixed voltage terminal and the voltage output from the adjustable terminal of the first adjustable resistor VR1can be set as needed.

In an example, the first input terminal Vin1is connected with a first fixed potential, and the second input terminal Vin2is connected with a second fixed potential, the second fixed potential is different from the first fixed potential such that a certain voltage (Vin1−Vin2), which is the input voltage of the voltage adjustment circuit for the common electrode, exists between the first input terminal Vin1and the second input terminal Vin2.

As shown inFIG. 2, in the prior art, a normal voltage adjustment circuit for the common electrode only comprises a first adjustable resistor VR1. Limited by the sensitivity and precision in the adjustment of the first adjustable resistor VR1, sometimes the voltage of the common electrode cannot meet requirements of the display apparatus, which results in occurring of a flicker phenomenon in pictures. In addition, if the first adjustable resistor VR1fails due to malfunctions, the voltage adjustment circuit for the common electrode cannot work normally and it has to replace the failed first adjustable resistor VR1to make the voltage adjustment circuit work normally. As a result, the voltage adjustment circuit has a low operation reliability.

In the technical solution of the present embodiment, the voltage adjustment circuit for the common electrode has the adjustment module which cooperates with the first adjustable resistor to adjust the resistance of the voltage adjustment circuit for the common electrode in order to adjust the output voltage of the common electrode. Therefore, the sensitivity and the precision in the adjustment of the output voltage for the common electrode are improved, which enables the common electrode to have a suitable voltage value so as to prevent the display apparatus from presenting the flicker phenomenon in the pictures.

A second manner is as follows. The first terminal of the adjustment module is connected to the first terminal of the first adjustable resistor, the second terminal of the adjustment module is connected to the second terminal of the first adjustable resistor, the adjustable terminal of the adjustment module and the adjustable terminal of the first adjustable resistor are connected together to the output terminal of the voltage adjustment circuit for the common electrode.

For example, as shown inFIG. 3, the adjustment module may comprise the second adjustable resistor VR2, the first terminal of the second adjustable resistor VR2is connected to the first terminal of the first adjustable resistor VR1, the second terminal of the second adjustable resistor VR2is connected to the second terminal of the first adjustable resistor VR1, and the adjustable terminals of the second adjustable resistor VR2and the first adjustable resistor VR1are connected together to the output terminal Voutof the voltage adjustment circuit for the common electrode.

For facilitating analysis,FIG. 4is an equivalent circuit structure of the circuit structure shown inFIG. 3.

As can be seen fromFIG. 3, the first adjustable resistor VR1is divided into a first-first adjustable resistor VR11and a first-second adjustable resistor VR12by its adjustable terminal, and similarly, the second adjustable resistor VR2is divided into a second-first adjustable resistor VR21and a second-second adjustable resistor VR22by its adjustable terminal. InFIG. 4, the first-first adjustable resistor VR11and the second-first adjustable resistor VR21are connected in parallel to generate a resistance Rup1for this part, and the first-second adjustable resistor VR12and the second-second adjustable resistor VR22are connected in parallel to generate a resistance Rdown1for this part.

As can be seen from the expressions (1), (2) and (3), a suitable output voltage Voutcan be obtained by reasonably assigning the resistances of the first-first adjustable resistor VR11, the first-second adjustable resistor VR12, the second-first adjustable resistor VR21and the second-second adjustable resistor VR22.

Further, when one of the adjustable resistors fails due to the malfunctions or other reasons, the other adjustable resistor may still work to remain adjusting the output voltage of the voltage adjustment circuit for the common electrode, which improves the operation reliability of the voltage adjustment circuit for the common electrode.

However, if the resistance of the first-first adjustable resistor VR11is zero, that is, the resistance of the one-second adjustable resistor VR12is equal to the resistance of the first adjustable resistance VR1, as can be seen fromFIG. 4, the second-first adjustable resistor VR21is short-circuited by the first-first adjustable resistor VR11, such that the overall resistance of the voltage adjustment circuit for the common electrode is small, and thus currents flowing through the first fixed resistor R1and the second fixed resistor R2would be large, which may damage the first fixed resistor R1, the second fixed resistor R2and other electrical devices and influence the normal usage of the voltage adjustment circuit for the common electrode.

In order to avoid an occurrence of such bad effects, the adjustment module may further comprise a third fixed resistor R3and a fourth fixed resistor R4. Now, as shown inFIG. 5, the first terminal of the second adjustable resistor VR2is connected to a first terminal of the third fixed resistor R3, and a second terminal of the third fixed resistor R3is connected to the first terminal of the first adjustable resistor VR1and the second terminal of the first fixed resistor R1; and the second terminal of the second adjustable resistor VR2is connected to a first terminal of the fourth fixed resistor R4, and a second terminal of the fourth fixed resistor R4is connected to the second terminal of the first adjustable resistor VR1and the second terminal of the second fixed resistor R2.

In order to describe the structure of the voltage adjustment circuit for the common electrode shown inFIG. 5more conveniently and intuitively, the structure shown inFIG. 5can be equivalent to the structure shown inFIG. 6. As can be seen fromFIG. 6, the first adjustable resistor VR1is divided into the first-first adjustable resistor VR11and the first-second adjustable resistor VR12by its adjustable terminal, and similarly, the second adjustable resistor VR2is divided into the second-first adjustable resistor VR21and the second-second adjustable resistor VR22by its adjustable terminal. The second-first adjustable resistor VR21is connected to the third fixed resistor R3in series, and then they are commonly connected with the first-first adjustable resistor VR11in parallel, which generates a resistance Rup2. The second-second adjustable resistor VR22is connected to the fourth fixed resistor R4in series, and then they are common connected with the first-second adjustable resistor VR12in parallel, which generates a resistance Rdown2. Then the structure shown inFIG. 6can be simplified as that the first fixed resistor R1, Rup2, Rdown2and the second fixed resistor R2are connected in series.

As can be seen from the expressions (4), (5) and (6), the adjustment of the voltage value output from the output terminal Voutof the voltage adjustment circuit for the common electrode can be realized by reasonably assigning the resistances of the first-first adjustable resistor VR11, the first-second adjustable resistor VR12, the second-first adjustable resistor VR21and the second-second adjustable resistor VR22, i.e., by reasonably adjusting the adjustment terminals of the first adjustable resistor VR1and the second adjustable resistor VR2. The precision and the sensitivity of the adjustment are both high.

Further, if the first adjustable resistor VR1fails, for example, if the first adjustable resistor VR1is open-circuited or cannot adjust its resistance, the voltage adjustment circuits for the common electrode as shown inFIG. 3,FIG. 4,FIG. 5andFIG. 6can still realize the adjustment of their output voltages by adjusting the second adjustable resistor VR2, such that the common electrode can obtain a voltage value meeting the requirements of the display apparatus.

Exemplarily, in an embodiment of the present disclosure, adjustment ranges of the first adjustable resistor VR1and the second adjustable resistor VR2are both 0-2.2 kΩ. The resistance of the first fixed resistor R1can set as 3.32 kΩ. The resistances of the second fixed resistor R2and the third fixed resistor R3can be set as 1 kΩ. The resistance of the fourth fixed resistor R4can set as 2.2 kΩ In particular, the resistances of the fixed resistors or the adjustable resistors can be selected after determining a range of the output voltage of the voltage adjustment circuit by detailed calculations based on a screen size of the practical display apparatus.

In practical use, the second input terminal Vin2of the voltage adjustment circuit may be grounded, and at this time the input voltage of the voltage adjustment circuit is the potential value input from the first input terminal Vin1.

Any electrical signal would be influenced by factors such as electrical devices to carry noises during transmission. In order to eliminate the noise in the voltage value output from the output terminal Voutof the voltage adjustment circuit for the common electrode, as shown inFIG. 7, the voltage adjustment circuit for the common electrode may further comprise a first capacitor C1whose first terminal is connected to the output terminal Voutof the voltage adjustment circuit for the common electrode, and whose second terminal is grounded. The first capacitor C1is used to reduce the noise in the voltage value output from the voltage adjustment electrode for the common electrode, in order to improve the operation reliability of the voltage adjustment circuit for the common electrode.

As shown inFIG. 7, in order to avoid that the failure of the first capacitor C1due to its malfunctions influences the operation reliability of the voltage adjustment circuit for the common electrode, the voltage adjustment circuit for the common electrode may further comprise a second capacitor C2whose first terminal is connected to the output terminal Voutof the voltage adjustment circuit for the common electrode, and whose second terminal is grounded. In other words, the second capacitor C2is connected to the first capacitor C1in parallel.

In order to further improve the operation reliability and the sensitivity and precision in the adjustment of the voltage adjustment circuit for the common electrode, as shown inFIG. 8, the voltage adjustment circuit for the common electrode may further comprise a third adjustable resistor VR3, a first terminal of the third adjustable resistor VR3is connected to the first terminal of the second adjustable resistor VR2, a second terminal of the third adjustable resistor VR3is connected to the second terminal of the second adjustable resistor VR2, and an adjustable terminal of the third adjustable resistor VR3is connected to the adjustable terminal of the second adjustable resistor VR2.

Similar to the above, the voltage adjustment circuit for the common electrode shown inFIG. 8can be equivalent to the structure shown inFIG. 9. As can be seen fromFIG. 9, the third adjustable resistor VR3is divided into a third-first adjustable resistor VR31and a third-second adjustable resistor VR32by its adjustable terminal. The third-first adjustable resistor VR31is connected to the second-first adjustable resistor VR21in parallel, and the third-second adjustable resistor VR32is connected to the second-second adjustable resistor VR22in parallel. Then, it can be known in connection with the above that the second-first adjustable resistor VR21is connected to the third-first adjustable resistor VR31in parallel, and a resistance after such parallel connection may be referred to as VRparallel1; the VRparallel1is connected to the third fixed resistor R3in series and then is commonly connected to the first-first adjustable resistor VR11in parallel, which generates a resistance of Rp3. Similarly, the second-second adjustable resistor VR22is connected to the third-second adjustable resistor VR32in parallel, a resistance after such parallel connection may be referred to as VRparallel2; the VRparallel2is connected to the fourth fixed resistor R4in series and then is commonly connected to the first-second adjustable resistor VR12, which generates a resistance of Rdown3. Then the structure shown inFIG. 9can be simplified as that the first fixed resistor R1, Rup3, Rdown3and the second fixed resistor R2are connected in series.

Combining the expressions (8) and (10), compared with equation (5), it can be seen that the sensitivity and precision of the change of Rup3are higher than those of Rup2, and similarly the sensitivity and precision of the change of Rdown3are higher than those of Rdown2. Therefore, it can be known that the sensitivity and precision of the change of Voutin equation (7) are higher than those of Voutin equation (4).

In addition, the voltage adjustment circuit for the common electrode with the three adjustable resistors has a higher reliability and a longer lifetime than the voltage adjustment circuit for the common electrode with the two adjustable resistors.

An embodiment of the present disclosure also provides a display apparatus comprising any voltage adjustment circuit for a common electrode described in the above. The display apparatus can be any product or means with the display function such as a liquid crystal panel, an electronic paper, an OLED panel, a cell phone, a plate computer, a TV set, a display, a notebook computer, a digital photo frame, a navigator and so on.

The above descriptions only illustrate the specific embodiments of the present invention, and the protection scope of the present invention is not limited to this. Given the teaching as disclosed herein, variations or substitutions, which can easily occur to any skilled pertaining to the art, should be covered by the protection scope of the present invention. Thus, the protection scope of the present invention is defined by the claims.