TW201033983A - Temperature compensation method and driving method for liquid crystal display - Google Patents

Abstract

In methods according to the invention, for reducing flicker of a display apparatus, respective best temperature-related voltages under several temperatures are found. Then, a temperature variation trend for the best temperature-related voltages is determined. Then, one of the best temperature-related voltages is chosen as a reference. Based on the temperature variation trend and the reference, a temperature compensation value is set to obtain compensated temperature-related voltages under other temperatures. Further, the display apparatus is driven based on the compensated temperature-related voltages.

Description

201033983 . * VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a method of reducing flicker of a liquid crystal display. More particularly, the present invention relates to a method of temperature compensation of a voltage to reduce flicker of a liquid crystal display. [Prior Art] Liquid crystal displays (LCDs) have the advantages of low radiation, low consumption, and the like, and have gradually become the mainstream of displays. However, due to the operational characteristics, there is a problem that a feed voltage (represented by the symbol AVP) inside the liquid crystal display device causes the screen to flicker (fllcker). Fig. 1A is a view showing the structure of a pixel (pixe|) of the conventional liquid crystal display. Fig. 1B shows a waveform diagram of Fig. 1A. As shown in Fig. 1A, the halogen 100 includes, in principle, a TFT transistor, a liquid crystal capacitor CLC, and a storage capacitor cs. In addition, there is a parasitic capacitance Cgd in the pixel 100. Basically, the through voltage ΔVp is caused by parasitic capacitance. Vg represents the gate voltage applied to the transistor (ie, the scan signal), Vs ❹ represents the source applied to the transistor _ (ie, the (four) signal), and Vd represents the gate voltage of the transistor ( (ie, The electric house of the pixel electrode). When the gate voltage Vg transitions from a high potential (Vgh) to a low potential _), this voltage transition affects the drain voltage Vd through the parasitic capacitance Vgd, resulting in the generation of the through voltage Δνρ. If the common voltage Vc〇m changes, the liquid crystal capacitor and/or the storage capacitor CS (4) will also generate the voltage z\VP due to the secret voltage Vd. If the through voltages 3 201033983, .l vv r\ Δ VP in the positive half cycle Τ+ and the negative half cycle 有_ have the same value, the flicker is less obvious. Therefore, in design, the parameters are usually adjusted for a given temperature (such as room temperature 25 ° c ~ 35 ° c), so that the positive half cycle T + and the negative half cycle T - within the penetration voltage Δν Ρ have the same value, To reduce the flicker effect. However, the inventors have found that the through voltage ΔνΡ is related to temperature. That is, if the temperature rises (or falls), the through voltage ΔνΡ also rises (or falls). Therefore, when the temperature rises (or falls), the through-voltage ΔνΡ in the positive half cycle Τ- and the negative half cycle Τ- is different from each other, so that the flicker effect is more serious. Therefore, the inventors have proposed a method for compensating for the flicker effect in order to reduce the flicker effect due to temperature fluctuations. SUMMARY OF THE INVENTION The present invention is directed to a temperature compensation method for a display that is capable of temperature compensation of a common voltage or source voltage to reduce flicker effects. The present invention relates to a display driving method for driving a display with a temperature-compensated common voltage or source voltage to reduce a flicker effect. According to an example of the present invention, a temperature compensation method for a display includes: finding respective optimal temperature-related voltages at a plurality of temperatures; and finding a temperature change trend of the optimal temperature-related voltages; according to a predetermined temperature, One of the optimal temperature-related voltages is selected as a reference point; and a temperature compensation value is set according to the temperature change trend and the reference point to obtain a compensated temperature-dependent voltage at other temperatures. According to another example of the present invention, a driving method for a display includes: finding a respective optimal temperature-dependent voltage at a plurality of temperatures; and finding a temperature change trend of the optimal temperature-related voltage of the 201033983; Temperature 'select one of the optimal temperature-related voltages as a reference point; according to the temperature change trend and the reference point, set a temperature compensation value to obtain a compensated temperature-dependent voltage at other temperatures; and according to the compensation The post-temperature dependent voltage 'drives the display. In order to make the above-mentioned contents of the present invention more comprehensible, the following specific embodiments will be described in detail below with reference to the accompanying drawings: [Embodiment] β is to compensate for the flicker effect caused by temperature fluctuation, the inventor first Find out the best common voltage Vcom at different temperatures. To this end, the inventors obtained experimentally, at several temperatures (25. 〇, 3 (rc, 35 it, 4 〇 C, 65 C), different common voltage values Vc 〇 m (〇56V, 〇58V, 0.60V) Through-voltage ΔVp (in db value) corresponding to 0.62V, 0.64V, 〇66v, 〇68V, 〇7〇ν, 〇72V, 〇_74V' 〇·76ν, 0_78V, 〇8〇ν, 〇82ν) This relationship is shown in Table 1. --- Table 1 Vcom 25〇C 30°C 35t 40°C 65〇C 0.56V -17.37db -18-8ldb _13_7db -11.53db -10.78db 0.58V - 20.69db -2〇.82db -16.59db -13.19db -12.55db 0.60V -20.69db -22_25db --__ -18.65db -16.75db -16.03db 0.62V -24.92db -25.38db -20.70db -18.51db - 17_71db 0.64V -27.50db -29.4Odb^ -23.11db -20.75db -19.80db 0.66V -27.50db -3〇.64db -26.09db -23.72db -25.90db 0.68V -32.55db -34.38db -29.64db - 34.85db -22.60db 5 201033983 1 WHOH^tr/A. 0.70V -37.77db -36.43db -38.87db -38.61db -19.38db 0.72V -43.16db -43.78db -43.86db -38_46db -16.43db 0.74V - 47.84db -48.20db -33.38db -32.45db -14.55db 0.76V -41.30db -40.56db -29.45db -28.14db -13.2 5db 0.78V -36.33db -34.86db -26.01db -24.51db -11_75db 0.80V -31.15db -31.39db -22.53db -21.43db -13.25db 0.82V -28.55db -28.71db -20.78db -20.12db -11.75 As can be seen from Table 1, at the different temperatures, the optimum common voltage Vcom (which corresponds to the minimum through voltage AVP) may be different, and the optimum common voltage Vcom is shifted in the same direction. That is to say, when the temperature rises, the minimum through voltage ΔνΡ tends to become larger, and the optimum common voltage Vcom tends to become smaller; and vice versa. In Table 1, at a temperature of 25 ° C, the optimum common voltage Vcom is 0.74 V, which corresponds to the minimum through voltage Δν Ρ (-47.84 (^, indicated by the bold slanting and bottom line); at a temperature of 30 ° Under C, the best common voltage Vcom is 0.74V, which corresponds to the minimum through voltage ΔνΡ(-48·2€3); at 35°C, the optimal common voltage Vcom is 0.72V, which corresponds to the minimum Through voltage △VpH^Aedb); at a temperature of 40 ° C, the optimum common voltage Vcom is 0.70V, because it corresponds to the minimum through voltage ΔVP (-38.61db); at a temperature of 65 ° C, the best common voltage Vcom is 0.66V because it corresponds to the minimum through voltage ΔνΡ (-25.90ο1ΐ3). After finding the trend of the optimum common voltage Vcom, the compensation value for the common voltage Vcom can be set according to this trend. That is, after finding the trend of the best common voltage Vcom, the best common voltage Vcom of a certain temperature can be selected as the reference point. Next, compensate for this reference point to get the common power Vcom after compensation at other temperatures. Then, the compensated common voltage vcom is applied to the pixels to reduce the flicker effect caused by the temperature fluctuation. In the present embodiment, the compensation method for the common voltage Vcom is, for example, (1) compensating the common voltage Vcom by the drive circuit, and (2) compensating the common voltage Vcom by means of the voltage dividing circuit. Of course, the compensation for the common electric power Vcom is not limited to these. Moreover, the present invention is not limited thereto. They are described in detail below. (1) Compensation of the common voltage Vcom by the drive circuit: When the common circuit Vcom is compensated by the drive circuit, a plurality of temperature-voltage (V-T) curves can be found in advance to compensate. Figure 2 shows a number of temperature-voltage (VT) curves, where the horizontal axis is the temperature (. 〇 and the vertical axis is the common voltage Vcom. That is, according to the trend found, each can be set at different temperatures. ® The appropriate slope of the temperature_voltage (VT) curve. After that, the common voltage Vcom is compensated according to this slope. For example, the slope includes: _imV/°C, -1.5mV/ °C ' -2mV/°c ' -2.5mV /〇c.....+1 mV/°C, +1.5mV/°C, +2mV/°C, +2.5mV/°C,···. Normally, it will be at room temperature (such as 25.) :~35. The best common voltage Vcom under the arm is set as the reference point, and a better compensation effect will be obtained. Taking the temperature 35 C as an example, the inventor believes that the slope is set to _彳mv/°c, which can be improved. Because of the flicker effect caused by temperature fluctuations, that is, when the slope is _1mv / C, the common voltage Vc 〇 m will drop by 1mV for every degree of temperature rise; 7 201033983 1 w Ming r r / \ · vice versa. Take Table 1 as an example 'Because the temperature is 35〇c, the best common voltage Ve. The towel is 0.72V. So 'the slope is _1 (11乂 /. (: lower ' when the temperature rises to 36 ° (: After compensation The voltage vcom is (0.72V+(-1mV)*1)=〇.719V. Similarly, when the slope is -ImV/t, when the temperature drops to 34. (:, the compensated common voltage Vcom is (0.72V+) (-1mV)*-1)=〇.72lV. The method of calculating the compensated common voltage VC〇m can be achieved by using a firmware. Alternatively, the above-mentioned method can be used to calculate the appropriate compensated common voltage at each temperature. Vcom, after that, all the compensated common voltage Vcom obtained is filled into the LUT (Check Table) unit. When the [the current internal temperature of the CD is detected], the internal unit temperature can be obtained by using the look-up unit. The compensation common voltage VeQm is appropriately compensated. (2) The common voltage Vc〇m is compensated by the voltage dividing circuit as described above. In the present embodiment, the trend of the optimum common voltage Vcom related to the temperature fluctuation can be found. According to this trend, the common voltage Vcom is compensated by a voltage dividing circuit composed of a heat-sensitive element. The heat-sensitive element is, for example but not limited to, a thermistor (positive temperature coefficient resistance, negative temperature coefficient resistance), Thermal induction transistors, thermal sensing sensors, etc. due to temperature changes When the voltage is changed, the impedance value of the heat-sensitive element changes accordingly, so it can be used to compensate for the flicker effect caused by temperature fluctuations. By properly designing the P of the thermally induced 7G piece and the value of the resistance and the impedance value of each heat-sensitive element Proportion, the voltage divider circuit formed by the thermal sensing element can simulate the above slope. So - the 'common voltage v_ after compensation is also related to the temperature variation. In the specific implementation, when the application is positive When the temperature coefficient resistor and the negative temperature coefficient resistor are used to form the voltage dividing circuit, the positive temperature coefficient resistor can be connected in series between the reference voltage source (or the common voltage Vcom) and the output node, and the negative temperature coefficient resistor is connected in series. Between the output node and the ground. Thus, the voltage output by the output node is a temperature dependent voltage that can be used to compensate for the common voltage Vcom. Figure 3 shows a flow chart for compensating a common voltage in accordance with an embodiment of the present invention. As shown in Fig. 3, in step 310, the best common voltage Vcom at each temperature is found. The details can be referred to the above description, and will not be repeated here. Next, in step 320, a temperature change tendency of the optimum common voltage Vcom is found. The details can be referred to the above description, and will not be repeated here. Next, in step 330, the optimum common voltage Vcom at a predetermined temperature is selected as a reference point. The details can be referred to the above description, and will not be repeated here. Next, in step 340, the temperature compensation value is set according to the temperature change trend and the reference point, 以 to compensate the common voltage Vcom. The details can be referred to the above description and will not be repeated here. According to this, the compensation of the common voltage Vcom can be completed. In addition, this embodiment can also be used to compensate the source voltage Vs. That is, the source voltage Vs is compensated in the above manner to make it temperature dependent. When the source voltage Vs is compensated, the common voltage Vcom may not be compensated. Alternatively, the source voltage Vs and the common voltage Vcom may be compensated, which are within the spirit and scope of the present invention. In summary, although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims. [Simple description of the drawing] Fig. 1A shows a structure of a pixel of the conventional liquid crystal display. Fig. 1B shows a waveform diagram of Fig. 1A. Fig. 2 shows a temperature-voltage (V-T) graph according to an embodiment of the present invention. Figure 3 is a flow chart showing the compensation of a common voltage in accordance with an embodiment of the present invention. [Main component symbol description] 100 : Alizarin M : TFT transistor

Clc ·Liquid Crystal Capacitor cs: Storage Capacitor

Cgd : storage capacitor △ VP : through voltage

Vg: gate voltage

Vs : source voltage

Vd: bungee voltage

Vcom: common voltage

Vgh: high potential of the gate voltage

Vgl: low potential of the gate voltage 201033983 τ+ : positive half cycle Τ-: negative half cycle 310~340 : steps

Claims (1)

201033983 I W4544^A VII. Patent application scope: 1. The temperature compensation method of the display includes: finding the respective optimal temperature-related voltages at a plurality of temperatures; finding a temperature of the optimal temperature-related voltages Changing trend; selecting one of the optimal temperature-related voltages as a reference point according to a predetermined temperature; and setting a temperature compensation value according to the temperature change trend and the reference point to obtain a compensated temperature at other temperatures a correlation voltage; wherein the optimal temperature-dependent voltage comprises at least one of a common voltage and a source voltage. _, 2. The temperature compensation method of the display as shown in the scope of the patent application, wherein the temperature change trend is that when the temperature rises, a minimum penetration voltage becomes larger, and the optimal temperature-dependent voltage changes. small. The temperature compensation method of the display as shown in the first aspect of the patent application, wherein the temperature change trend is such that when the temperature is lowered, a minimum penetration voltage becomes small, and the optimum temperature-dependent voltage becomes large. The temperature compensation method of the display as shown in item 1 of the patent application scope, wherein the step of setting the temperature compensation value comprises: finding a plurality of temperature-voltage curves; H according to the temperature change trend, Setting respective slopes of respective temperature and pressure curves at respective temperatures; and setting the temperature compensation value according to one of the slopes. Method 5: The temperature compensation of the display as shown in item 1 of the patent application scope, wherein the step of setting the temperature compensation value comprises: pre-discovering a plurality of temperature-voltage curves; 12 201033983 according to the temperature change trend 'set in each The respective slopes of the respective temperature-voltage curves at different temperatures; finding the respective temperature-dependent voltages at the respective temperatures according to the slopes, and filling in a look-up unit; and according to the display The current internal temperature is utilized by the look-up unit to obtain the compensated temperature-dependent voltage at the internal temperature. 6) The method for temperature compensation of a display as shown in the scope of the patent application, wherein the step of setting the temperature compensation value comprises: using a component consisting of a plurality of positive temperature coefficient resistors and a plurality of negative temperature coefficient resistors Press the circuit to compensate. 7. The driving method of the display, comprising: finding the respective optimal temperature-related voltages at a plurality of temperatures; finding a temperature change trend of the optimal temperature-related voltages; selecting the ones according to a predetermined temperature One of the optimal temperature-related voltages is a reference point; according to the temperature change trend and the reference point, a temperature compensation value is set to obtain a compensated temperature-dependent voltage at other temperatures; and the temperature-dependent voltage is driven according to the compensation The display; the optimum temperature-dependent voltage includes at least one of a common voltage and a source voltage. Method 8. In the driving space fee of the display shown in item 7 of the patent application scope, the temperature change trend is that when the temperature rises, a minimum pressure will become larger, and the optimal temperature related voltage will Become smaller. = In the driver of the display shown in item 7 of the patent application, the temperature change trend is such that when the temperature drops, a minimum voltage of 13 201033983 1 becomes smaller, and the optimum temperature-dependent voltage becomes larger. 10. The driving method of a display as shown in claim 7, wherein the step of setting the temperature compensation value comprises: finding a plurality of temperature-voltage curves; setting the temperature at each temperature according to the temperature change trend The respective slopes of the respective temperature-voltage curves; and the temperature compensation values are set according to one of the slopes. 11. The driving method of a display according to claim 7, wherein the step of setting the temperature compensation value comprises: finding a plurality of temperature-voltage curves in advance; setting the The respective slopes of the respective temperature-voltage curves; the respective compensated post-temperatures are used to find the relevant voltages at the respective temperatures according to the slopes, and fill in a look-up unit; and according to the display 11 The current internal temperature is utilized by the look-up unit to obtain the compensated temperature-dependent voltage at this internal temperature. 12. The driving method of the display as shown in claim 7 of the patent application, wherein the step of setting the temperature compensation value includes: the moving power::: number=:=: complex_temperature-