TWI514355B - Liquid crystal display - Google Patents

Description

LCD Monitor

The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display incorporating a key input.

In recent years, display devices for electronic devices, such as computer screens, televisions, and the like, have undergone significant development. Compared with the conventional cathode ray tube (CRT), the liquid crystal display panel has become a light weight, a small size, a large area, a small operating voltage, a low power consumption, and no radiation. The mainstream of the display panel. In recent years, popular portable electronic products, such as notebook computers, mobile phones, tablet display screens, etc., only the LCD screen can meet the portable requirements of light weight, small size, small area.

In order to enable the user to operate and set the electronic device of the liquid crystal display panel, in the liquid crystal driving circuit of the conventional liquid crystal display, an extra pin is usually added to receive the input signal of the button, which will increase the liquid crystal display. Cost of production. Alternatively, the button input can be integrated with the segment electrode or the common electrode, and a cycle time is divided during one screen period, and the display function of the liquid crystal display is turned off, and this period of time is used as a period during which the button input signal is accepted. To avoid the display screen of the LCD monitor being affected by the button input signal. For example, the last cycle time of each screen period is used as the period of key input, during which the LCD display will not be displayed. Since this method will cause the display screen to be interrupted for a long time, it affects the display quality of the liquid crystal display, such as a noticeable flickering of the image screen.

The invention provides a liquid crystal display, which can reduce the influence of the key input on the quality of the display picture, and can reduce the production cost of the liquid crystal display.

The invention provides a liquid crystal display comprising a liquid crystal display panel, a liquid crystal driving module and a key input unit. The liquid crystal display panel includes a plurality of display pixels. The liquid crystal driving module transmits a plurality of segment driving signals to the plurality of display pixels through the plurality of segment driving lines, wherein each segment driving signal includes a plurality of responsibility intervals, and each of the responsibility intervals includes a display interval and a detection interval. The liquid crystal driving module transmits the display data through the segment driving line in the display interval to drive the display pixels, and detects the user's key motion through the segment driving line in the detecting interval. The button input unit is coupled to the liquid crystal driving module to receive a button motion of the user.

In an embodiment of the present invention, the liquid crystal driving module adjusts the ratio of the display interval and the detection interval in the responsibility interval according to the charging and discharging speed of each display pixel.

In an embodiment of the invention, the liquid crystal driving module transmits a plurality of common driving signals to the plurality of display pixels through a plurality of common driving lines to drive corresponding display pixels.

In an embodiment of the invention, the liquid crystal driving module includes a segment driving signal generating unit and a common driving signal generating unit. The segment driving signal generating unit is coupled to the liquid crystal display panel and the key input unit for generating the plurality of segment driving signals for driving the display pixels in the display interval, and detecting the button actions in the detecting interval. The common driving signal generating unit is coupled to the liquid crystal display panel to generate the plurality of common driving signals to the plurality of display pixels to drive the display pixels.

In an embodiment of the invention, the segment driving signal generating unit includes a plurality of button detecting units, a plurality of first transmitting gates, a plurality of second transmitting gates, and a plurality of pull-down impedance units. The plurality of button detecting units are respectively coupled to the button input unit through the segment driving line to detect a button motion of the user and output a button signal accordingly. The plurality of first transmission gates are respectively coupled to display pixels through the segment driving lines, and each of the first transmission gates outputs a first data voltage according to a reverse control signal. The plurality of second transmission gates are respectively coupled to display pixels through the segment driving lines, and each of the second transmission gates outputs a second data voltage according to the inversion control signals. The plurality of pull-down impedance units are respectively coupled between the segment driving line and the ground voltage, and respectively lower the voltage of the segment driving line in the detecting interval.

In an embodiment of the invention, each of the pull-down impedance units is a transistor controlled by a pull-down control signal and turned on during the detection interval.

In an embodiment of the invention, the button input unit includes a plurality of pull-up resistors and a plurality of switch units. One of the plurality of pull-up resistors is coupled to an operating voltage. The plurality of switch units are respectively coupled between the plurality of segment drive lines and the other end of the pull-up resistor, and are turned on according to the button action.

In an embodiment of the invention, the resistance values of the respective pull-up resistors are much smaller than the equivalent resistance values of the corresponding display pixels.

In an embodiment of the invention, the common driving signal generating unit includes a plurality of third transmission gates and a plurality of fourth transmission gates. The plurality of third transmission gates are respectively coupled to the display pixels through the plurality of common driving lines, and each of the third transmission gates outputs a first common voltage according to the inversion control signals. The plurality of fourth transmission gates are respectively coupled to the display pixels through the plurality of common driving lines, and each of the fourth transmission gates outputs a second common voltage according to the inversion control signals.

In an embodiment of the invention, the detection interval is an integer multiple of a clock period of the operation clock signal of the liquid crystal display.

Based on the above, the present invention detects the user's keystrokes in the detection section of the segment driving signal through the segment driving line, so as to reduce the influence of the key input on the display picture quality and reduce the production cost of the liquid crystal display.

The above described features and advantages of the present invention will be more apparent from the following description.

FIG. 1 is a schematic diagram of a liquid crystal display according to an embodiment of the invention. Referring to FIG. 1 , the liquid crystal display 100 includes a liquid crystal display panel 102 , a liquid crystal driving module 104 , and a button input unit 106 . The liquid crystal display panel 102 includes a plurality of display pixels (not shown), and the key input unit 106 is configured to receive a button motion of the user. The liquid crystal driving module 104 transmits the plurality of segment driving signals SEG and the plurality of common driving signals COM to the display pixels of the liquid crystal display panel 102 through the plurality of segment driving lines SL1 and the plurality of common driving lines CL1. Each of the segment driving signals SEG includes a plurality of responsibility intervals, and each of the responsibility intervals includes at least one display interval and one detection interval. The liquid crystal driving module 104 transmits the display data through the segment driving line SL1 in the display interval to drive the display pixels, and detects the user's key motion through the segment driving line SL1 in the detecting interval.

For example, FIG. 2 is a schematic diagram showing waveforms of a segment drive signal and a common drive signal of a liquid crystal display having a quarter cycle and a 1/3 bias voltage according to an embodiment of the invention. Referring to FIG. 2, in the embodiment, the liquid crystal display 100 has four common driving lines CL1 and 20 segment driving lines SL1, and the common driving signals COM0~COM3 and the segment driving signals SEG0~SEG19 thereon have 1/4 cycle, 1/3 bias. That is, in the common driving signals COM0~COM3 and the segment driving signals SEG0~SEG19, the first driving voltage V1 and the second driving voltage V2 divide the voltage difference between the power supply voltage VDD and the power supply voltage VSS into three segments. That is, the segment drive signals SEG0~SEG19 and the common drive signals COM0~COM3 have four voltage levels. The common driving signals COM0 to COM3 and the segment driving signals SEG0 to SEG19 shown in FIG. 2 are when the display pixels on the liquid crystal display panel 102 are illuminated.

In addition, as can be seen from FIG. 2, the sector drive signals SEG0~SEG19 and the common drive signals COM0~COM3 each include four duty intervals during one screen period. Each of the responsibility intervals includes a display interval and a detection interval. The liquid crystal driving module 104 can transmit the display pixels on the liquid crystal display panel 102 through the segment driving line SL1 in the display interval to drive the display pixels. A screen is displayed on the display panel 102. In the detection interval, the liquid crystal driving module 104 disables the display of the data output, and detects the user's key motion through the segment driving line SL1.

It should be noted that the common driving signals COM0~COM3 and the segment driving signals SEG0~SEG19 in this embodiment are only an exemplary embodiment of the present invention, and are not limited thereto, and the signals and regions are jointly driven in practical applications. The number of segment drive signals will vary with the number of common drive lines and the number of segment drive lines, and the common drive signal and the segment drive signal may have different cycle numbers (ie, the number of duty intervals) during a picture period. With different partial pressure levels.

By dividing a part of each responsibility interval in the segment drive signal SEG as a detection user button action, not only can increase the additional detection pin position to reduce the production cost, but also detect the period of the button action. Evenly dispersing in the respective duty intervals can further improve the quality of the display screen of the liquid crystal display panel 102, for example, to improve the flickering situation of the image screen in the prior art.

3 is a schematic diagram of a liquid crystal display according to another embodiment of the present invention. Referring to FIG. 3 , further, the liquid crystal driving module 104 of the liquid crystal display 300 can include a segment driving signal generating unit 302 and a common driving signal generating unit 304 . As shown in FIG. 3, the segment driving signal generating unit 302 is coupled to the liquid crystal display panel 102 and the key input unit 106, and the common driving signal generating unit 304 is coupled to the liquid crystal display panel 102. The segment driving signal generating unit 302 is configured to generate the segment driving signal SEG to drive the display pixel in the display interval, and detect the user's key motion in the detection interval. In addition, the common driving signal generating unit 304 generates a common driving signal COM to the display pixel to cooperate with the generation of the segment driving signal SEG to drive the display pixel.

4 is a schematic diagram of a liquid crystal display according to another embodiment of the present invention. Referring to FIG. 4 , in detail, the segment driving signal generating unit 302 of the liquid crystal display 400 may include a plurality of button detecting units 402 , a plurality of transmission gates T1 , a plurality of transmission gates T2 , and a plurality of pull-down impedance units 404 . The common drive signal generating unit 304 includes a plurality of transmission gates T3 and a plurality of transmission gates T4, and the key input unit 106 includes a plurality of pull-up resistors RU1 and a plurality of switching units 406. To simplify the description, the present embodiment only shows a coupling relationship between a segment drive line SL1, a common drive line CL1 and a corresponding display pixel P1.

The display pixel P1 includes series equivalent resistances R1 and R2 and an equivalent capacitance C1. The button detecting unit 402 is coupled to the switch unit 406 in the key input unit 106 through the segment driving line SL1. The transmission gate T1 and the transmission gate T2 are connected to the display panel P1 through the corresponding segment driving line coupling SL1. The pull-down impedance unit 404 is coupled between the segment drive line SL1 and the ground voltage GND. The transmission gate T3 and the transmission gate T4 are coupled to the SL1 display pixel P1 through the corresponding common driving line. One end of the pull-up resistor RU1 is coupled to an operating voltage VC, and the switch unit 406 is coupled between the other end of the pull-up resistor RU1 and the segment driving line SL1. In the present embodiment, the pull-impedance unit 404 is implemented by using a transistor M1, but is not limited thereto. The transistor M1 is coupled between the segment drive line SL1 and the ground voltage GND, and the gate of the transistor M1 receives the pull control signal SD1. Additionally, button detection unit 402 can be implemented, for example, with a Schmitt trigger.

As shown in FIG. 4, the transmission gate T1 and the transmission gate T2 are controlled by a reverse control signal SR1, and the first data voltage VS1 and the second data voltage VS2 are respectively outputted in the display interval for output on the segment drive line SL1. The segment drive signal SEG. Similarly, the transmission gate T3 and the transmission gate T4 are also controlled by the inversion control signal SR1, and the first common voltage VC1 and the second common voltage VC2 are respectively outputted in the display interval to output the common driving signal COM on the common driving line CL1. . In the detection interval, the transmission gate T1 and the transmission gate T2 are controlled by the inversion control signal SR1 to stop outputting the first data voltage VS1 and the second data voltage VS2. At the same time, the transistor M1 is controlled to be turned on by the pull-down control signal SD1, so that the charge stored by the display pixel P1 in the display interval by the segment drive signal SEG and the common drive signal COM can be driven through the segment. The line SL1 and the transistor M1 flow to the ground voltage GND, and the voltage level on the segment drive line SL1 is pulled low.

Thus, the charge stored in the display pixel P1 is directed to the ground voltage GND, and the voltage level on the segment drive line SL1 can be pulled down to avoid the charge stored in the display pixel P1 in the display interval affecting the button detection unit. The judgment of 402. If the user does not perform a button action in the detection interval, the voltage level on the segment drive line SL1 will remain at a low voltage level, and the button detection unit 402 may output a corresponding detection result (eg, the output is low). The voltage logic level button signal S1) to the subsequent application circuit performs corresponding circuit operation. In contrast, if the user performs a key operation in the detection interval, the switch unit 406 will be turned on, and the pull-up resistor RU1 and the transistor M1 (ie, the pull-down impedance unit 404) divide the operating voltage VC, thereby The voltage level on the segment drive line SL1 is pulled high. The button detecting unit 402 also outputs a corresponding detection result (for example, the button signal S1 outputting the high voltage logic level) to the application circuit of the subsequent stage according to the pulled voltage level to perform corresponding circuit operation.

It is worth noting that in order to prevent the user from performing a button operation in the display interval, the switch unit 406 is turned on, thereby affecting the display result of the display pixel P1. When designing the resistance value of the pull-up resistor RU1, it is preferable to design each pull-up resistor. The resistance value of RU1 is much smaller than the equivalent resistance of its corresponding display pixel P1, that is, the resistance value of the pull-up resistor RU1 is much smaller than the equivalent resistance R1, R2. In addition, considering that the liquid crystal display panel may have different equivalent capacitance values of the display pixels P1 in different display panels due to process differences during production, the liquid crystal driving module 104 may be charged according to the equivalent capacitance C1 of the display pixel P1. The discharge speed adjusts the display interval and the proportion of the detection interval in the responsibility interval, so that the button detecting unit 402 can correctly detect the button action.

For example, the inversion control signal SR1 can be adjusted in a program-controlled manner to increase or decrease the length of the detection interval, so that the liquid crystal driving module 104 has sufficient time to discharge the equivalent capacitance C1 of the display pixel P1. And detect the user's button actions. 5A and 5B are waveform diagrams of the segment driving signal SEG and the inversion control signal SR1, wherein the duty cycle of the inversion control signal SR1 of FIG. 5A is the clock of the operating clock signal of the liquid crystal display 400. The period CLK is 1 times, and the duty cycle of the inversion control signal SR1 of FIG. 5B is 5 times the clock period CLK of the operation clock signal. By adjusting the duty cycle of the inversion control signal SR1 and relatively adjusting the length of the detection interval, the duty cycle of the inversion control signal SR1 is an integer multiple of the clock cycle CLK, that is, the detection interval is the clock cycle. An integer multiple of CLK.

In summary, the present invention detects the user's keystrokes in the detection section of the segment drive signal through the segment drive line, thereby reducing the influence of the key input on the display picture quality and reducing the production cost of the liquid crystal display. In addition, by adjusting the proportion of the detection interval in the segment drive signal in each responsibility interval, the liquid crystal drive module can be applied to the liquid crystal display panel with different process parameters, thereby improving the applicability.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100, 300, 400. . . LCD Monitor

102‧‧‧LCD panel

104‧‧‧LCD driver module

106‧‧‧Key input unit

302‧‧‧ Segment Drive Signal Generation Unit

304‧‧‧Common Drive Signal Generation Unit

402‧‧‧Key detection unit

404‧‧‧ Pulldown impedance unit

406‧‧‧Switch unit

SL1‧‧‧ segment drive line

CL1‧‧‧Common drive line

SEG, SEG0~SEG19‧‧‧ segment drive signals

COM, COM0~COM3‧‧‧Common drive signal

V1, V2‧‧‧ drive voltage

T1~T4‧‧‧Transmission gate

RU1‧‧‧ Pull-up resistor

P1‧‧‧ display pixels

R1, R2‧‧‧ equivalent resistance

C1‧‧‧ equivalent capacitance

GND‧‧‧ Grounding voltage

M1‧‧‧O crystal

SR1‧‧‧Reverse Control Signal

VS1, VS2‧‧‧ data voltage

VC1, VC2‧‧‧ common voltage

S1‧‧‧ button signal

CLK‧‧‧ clock cycle

FIG. 1 is a schematic diagram of a liquid crystal display according to an embodiment of the invention.

FIG. 2 is a schematic diagram of waveforms of a segment driving signal and a common driving signal according to an embodiment of the invention.

3 is a schematic diagram of a liquid crystal display according to another embodiment of the present invention.

4 is a schematic diagram of a liquid crystal display according to another embodiment of the present invention.

5A and FIG. 5B are schematic diagrams showing waveforms of a segment driving signal and a reverse control signal according to an embodiment of the invention.

100. . . LCD Monitor

102. . . LCD panel

104. . . LCD driver module

106. . . Key input unit

SL1. . . Zone drive line

CL1. . . Common drive line

SEG. . . Zone drive signal

COM. . . Common drive signal

Claims (8)

A liquid crystal display comprising: a liquid crystal display panel comprising a plurality of display pixels; a liquid crystal driving module, wherein the plurality of segment driving signals are respectively transmitted to the display pixels through the plurality of segment driving lines, wherein each of the pixels The segment drive signals transmitted by the segment drive lines respectively comprise a plurality of responsibility intervals, each of the responsibility intervals includes a display interval and a detection interval, and the liquid crystal driving module transmits the display data through the segment drive lines in the display interval. The driving pixels are driven to detect a button operation of the user through the segment driving lines, and the liquid crystal driving module transmits a plurality of common driving signals to the plurality of common driving lines to The display pixels are driven to drive the corresponding display pixels, wherein the liquid crystal driving module includes: a segment driving signal generating unit coupled to the liquid crystal display panel and the key input unit to generate the segment driving signals. Driving the display pixels in the display interval, and detecting the button action in the detection interval; and a common driving signal generating unit coupled to the liquid crystal display Panel generates the plurality of common drive signals to the plurality of display pixels for driving the plurality of display pixels. And a button input unit coupled to the liquid crystal driving module to receive the button action of the user. The liquid crystal display of claim 1, wherein the liquid crystal driving module further adjusts the display interval and the proportion of the detection interval in the responsibility interval according to the charging and discharging speed of each display pixel. The liquid crystal display device of claim 1, wherein the segment driving signal generating unit comprises: a plurality of button detecting units coupled to the button input unit through the segment driving lines, and detecting the button action And outputting a button signal; the plurality of first transmission gates are respectively coupled to the display pixels through the segment driving lines, and each of the first transmission gates outputs a first data voltage according to a reverse control signal; a plurality of second transmission gates respectively coupled to the display pixels through the segment driving lines, each of the second transmission gates outputting a second data voltage according to the inversion control signal; and a plurality of pull-down impedance units, respectively The voltage is coupled between the segment drive lines and a ground voltage, and the voltages on the segment drive lines are respectively pulled down in the detection interval. The liquid crystal display of claim 3, wherein each of the pull-down impedance units is a transistor controlled by a pull-down control signal, and is turned on in the detection interval. The liquid crystal display of claim 3, wherein the button input unit comprises: a plurality of pull-up resistors, one end of which is coupled to an operating voltage; and a plurality of switch units respectively coupled to the segment drive lines Between the other ends of the pull-up resistors, they are turned on according to the button operation. The liquid crystal display according to claim 5, wherein the resistance value of each of the pull-up resistors is much smaller than the equivalent resistance value of the corresponding display pixel. The liquid crystal display of claim 3, wherein the common driving signal generating unit comprises: a plurality of third transmission gates coupled to the display pixels through the common driving lines, each of the third transmission gates And outputting a first common voltage according to the reverse control signal; and a plurality of fourth transmission gates respectively coupled to the display pixels through the common driving lines, wherein each of the fourth transmission gates outputs a signal according to the reverse control signal The second common voltage. The liquid crystal display of claim 1, wherein the detection interval is an integer multiple of a clock period of an operation clock signal of the liquid crystal display.