CN1920505B - Temperature sensor, thin film transistor array panel, liquid crystal display - Google Patents

Abstract

A temperature sensor for a display device is provided, which includes a substrate for the display devices, and a temperature sensing line formed on the substrate. The temperature sensing line is a conductor.

Description

Temperature sensor, thin film transistor array panel, liquid crystal display

related application

This application claims priority from Korean Patent Application No. 2005-0064147 filed on July 15, 2005 at the Korean Intellectual Property Office and Korean Patent Application No. 2006-0002586 filed on January 10, 2006, the entire contents of which incorporated herein by reference. the

technical field

The present invention relates to a temperature sensor for a display device, a thin film transistor array panel including the temperature sensor, and a liquid crystal display.

Background technique

Display devices used for displays of computers and televisions include self-luminous display devices and non-luminous display devices. Self-emissive display devices include organic light-emitting displays (OLEDs), vacuum fluorescent displays (VFDs), field emission displays (FEDs), and plasma flat panel displays (PDPs), and non-emissive display devices include liquid crystal displays (LCDs). Unlike self-emitting displays, non-emitting displays require a light source to display images.

The LCD includes two panels provided with field-induced electrodes with a dielectrically anisotropic liquid crystal (LC) layer interposed therebetween. A voltage is supplied to the field-generating electrodes to generate an electric field across the LC layer. The transmittance of light passing through the liquid crystal layer changes according to the strength of the generated electric field, which can be controlled by the applied voltage. Therefore, a desired image is displayed by adjusting the applied voltage.

The light source for the LCD can be a lamp connected to the LCD, or it can be an ambient light source such as the sun.

Since optical characteristics of liquid crystals of the LC layer vary according to temperature, temperature variations of the LCD affect reliability of the LCD. For example, optical properties (eg, refractive index, dielectric constant, elastic coefficient, and viscosity of liquid crystal) are inversely proportional to thermal energy of liquid crystal molecules, and their values decrease as the temperature of liquid crystal increases.

The operating characteristics of components mounted on or integrated with the LCD also change with temperature.

A temperature sensor is provided on a printed circuit board (PCB) on which a plurality of driving circuits are mounted to detect the temperature of the LCD. However, the PCB is usually placed on the back of the LCD where the lights and any other heat generating parts are placed. The temperature sensor is not provided on the front side of the LCD on which the LC layer is formed. Therefore, the temperature sensor detects the temperature of the back of the LCD with large temperature fluctuations. The temperature detected by the temperature sensor is very different from the temperature of the LC layer, and the LCD temperature compensation based on the backside temperature of the LC layer is not accurate.

Another disadvantage of the above structure is that the temperature sensor is independently installed on the PCB. This independent installation increases the design redundancy of the LCD, thereby increasing the production cost.

Contents of the invention

The purpose of the present invention is to solve the problems of the conventional technology.

In one aspect, the invention is a temperature sensor for a display having a substrate. The sensor includes temperature sensing lines formed on the substrate, wherein the temperature sensing lines are conductors.

In another aspect, the present invention is a thin film transistor array panel including a substrate and thin film transistors and temperature sensing lines formed on the substrate. A thin film transistor has a gate electrode, a source electrode, and a drain electrode. A temperature sensing line is formed on the same layer as the gate electrode or the source and drain electrodes.

In another aspect, the present invention is a liquid crystal display including a pixel, a first signal line connected to the pixel, and a second signal line connected to the pixel and crossing the first signal line. The liquid crystal display further includes temperature sensing lines separated from the first and second signal lines, wherein the temperature sensing lines are formed on the same layer as the first or second signal lines.

In another aspect, the invention is a driver circuit for a liquid crystal display having a liquid crystal panel assembly. The drive circuit includes a digital variable resistor (DVR) for generating a first voltage; a temperature sensing unit connected to the DVR and generating a second voltage; and a common voltage generator connected to the temperature sensing unit and based on the second voltage A common voltage is generated with the third voltage received from the liquid crystal panel assembly.

In another aspect, the invention is a controlled scintillation system. The flicker control system includes a liquid crystal display provided with a liquid crystal panel assembly; a photographing device used for photographing the liquid crystal display; and an electronic device connected with the liquid crystal display and the photographing device. The liquid crystal display includes a DVR for generating a first voltage; a temperature sensing unit connected to the DVR and generating a second voltage; and a common voltage generator connected to the temperature sensing unit based on the second voltage and received from the liquid crystal panel assembly The third voltage generates a common voltage.

Description of drawings

The present invention will become apparent by describing in detail its preferred embodiments with reference to the accompanying drawings, in which:

1 is a block diagram of an LCD according to an embodiment of the present invention;

2 is an equivalent circuit diagram of a pixel of an LCD according to an embodiment of the present invention;

3 is a perspective view of an LCD according to an embodiment of the present invention;

4 is a layout diagram of a TFT array panel for LCD according to an embodiment of the present invention;

5 is a cross-sectional view of the LCD shown in FIG. 4 taken along line V-V;

Figure 6 is a sectional view of the LCD shown in Figure 4 taken along the line VI-VI'-VI";

7 is a cross-sectional view of the LCD shown in FIG. 4 taken along line VII-VII;

8 is an equivalent circuit diagram of a temperature sensor according to an embodiment of the present invention;

9 is a graph of characteristics of an output voltage with respect to a temperature change of a temperature sensor according to an embodiment of the present invention;

10 is a block diagram of a signal controller according to another embodiment of the present invention;

11 is a block diagram of an LCD according to another embodiment of the present invention;

Fig. 12 shows the flicker adjustment system of LCD according to another embodiment of the present invention;

FIG. 13 shows a block diagram of an LCD flicker adjustment system according to another embodiment of the present invention;

FIG. 14 shows an example of a circuit diagram of a temperature sensing unit and a common voltage generator shown in FIG. 13;

15 is a graph showing resistance characteristics based on temperature of a temperature sensor according to another embodiment of the present invention; and

16a and 16b are graphs illustrating common voltages with and without temperature compensation applied according to another embodiment of the present invention.

Detailed ways

Hereinafter, the present invention will be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. However, the present invention can be embodied in many different forms and is not limited to the embodiments set forth herein.

In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Like reference numerals refer to like elements throughout. It will be understood that when an element such as a layer, film, region, substrate, or panel is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present.

A temperature sensor for a display device, a thin film transistor array panel including a temperature sensor, and a liquid crystal display according to embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram of an LCD according to an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram of a pixel of the LCD according to an embodiment of the present invention, and FIG. 3 is a perspective view of an LCD according to an embodiment of the present invention.

Referring to FIG. 1, an LCD according to an embodiment of the present invention includes an LC panel assembly 300, a gate driver 400 and a data driver 500 connected thereto, a grayscale voltage generator 800 connected to the data driver 500, and a temperature sensing unit 50 and a control Signal controller 600 of the above elements.

In the structure diagram shown in FIG. 2 , the LC panel assembly 300 includes a lower panel 100 , an upper panel 200 , and an LC layer 3 interposed therebetween. 1 and 2, the LC panel assembly 300 includes a plurality of display signal lines G ₁ -G _n and D ₁ -D _m , and a plurality of pixels PX connected thereto and arranged substantially in a matrix.

Display signal lines G ₁ -G _n and D ₁ -D _m are disposed on the lower panel 100 and include a plurality of gate lines G ₁ -G _n and a plurality of data lines D ₁ -D _m . The gate lines G ₁ -G _n transmit gate signals (also referred to as scan signals), and the data lines D ₁ -D _m transmit data signals. The gate lines G ₁ -G _n extend substantially in a first direction and are substantially parallel to each other, and the data lines D ₁ -D _m extend substantially in a second direction and are substantially parallel to each other. The first direction and the second direction are substantially perpendicular to each other.

Each pixel PX, for example, the pixel PX connected to the i-th gate line Gi ( _i =1, 2, . . . , n) and the j-th data line Dj (i=1, 2, . . . , m), Each includes a switching element Q connected to signal lines Gi _{and Dj} . Each pixel PX also includes an LC capacitor Clc connected to the switching element Q and a storage capacitor Cst. If not needed, the storage capacitor Cst can be ignored.

A switching element Q (for example, a TFT) is provided on the lower panel 100, and has three terminals: a control terminal connected to the gate line _Gi ; an input terminal connected to the data line _Dj ; and connected to the LC capacitor Clc and the storage terminal. Capacitor Cst at the output.

The LC capacitor Clc includes the pixel electrode 191 provided on the lower panel 100 and the common electrode 270 provided on the upper panel 200 as two terminals. The LC layer 3 disposed between the two electrodes 191 and 270 acts as a dielectric layer of the LC capacitor Clc. The pixel electrode 191 is connected to the switching element Q, and the common electrode 270 is supplied with a common voltage Vcom. The common electrode 270 covers the entire surface of the upper panel 200 . In some embodiments, the common electrode 270 may be disposed on the lower panel 100, and the electrodes 191 and 270 may be in a strip shape or a strip shape.

The storage capacitor Cst is an auxiliary capacitor for the LC capacitor Clc. The storage capacitor Cst includes the pixel electrode 191 and an individual data line (not shown) disposed on the lower panel 100 . The signal line overlaps the pixel electrode 191 through an insulator between the signal line and the pixel electrode 191, and is supplied with a predetermined voltage (for example, a common voltage Vcom). Optionally, the storage capacitor Cst includes the pixel electrode 191 and an adjacent gate line called a previous gate line. In this case, an insulator is interposed between the former gate line and the pixel electrode 191 .

Color display can be achieved in a number of different ways. One implementation requires spatial segmentation whereby each pixel uniquely represents one primary color such that the spatial sum of groups of pixels represents the desired color. Another approach requires temporal segmentation whereby each pixel sequentially represents a different primary color such that the temporal sum of the primary colors is considered the desired color. An exemplary set of primary colors includes red, green, and blue. FIG. 2 shows an example of realizing spatial division, in which each pixel includes a color filter 230 representing a primary color in the area of the upper panel 200, which is disposed opposite the pixel electrode 191 with respect to the LC layer. Optionally, the color filter 230 may be disposed above or below the pixel electrode 191 on the lower panel 100 .

As shown in FIG. 2, a light shielding film 220 (for example, a black matrix (black matrix) for preventing light loss) is formed on the upper panel 200, and has an opening in a region corresponding to the pixel electrode 191 or the color filter 230. .

Attached to the outer surfaces of the panels 100 and 200 of the panel assembly 300 are a pair of polarizers (not shown) for polarizing light.

The gray voltage generator 800 generates two sets of gray voltages (or two sets of reference gray voltages) related to the transmittance of the pixel. One set of grayscale voltages has a positive polarity with respect to the common voltage Vcom, and the other set of grayscale voltages has a negative polarity corresponding to the common voltage Vcom.

The gate driver 400 is connected to the gate lines G ₁ -G _n of the panel assembly 300, and synthesizes a gate-on voltage Von and a gate-off voltage Voff to generate a selection voltage for applying to the gate lines G ₁ -G _n . signal.

The data driver 500 is connected to the data lines D ₁ -D _m of the panel assembly 300 and applies a data voltage selected from gray voltages provided by the gray voltage generator 800 to the data lines D ₁ -D _m . If the gray voltage generator 800 supplies only a predetermined amount of the reference gray voltage (which is opposite to the gray voltage corresponding to the entire gray), the data driver 500 divides the reference gray voltage to generate the gray corresponding to the entire gray. voltage and select the data voltage from the generated grayscale voltages.

The temperature sensing unit 50 is formed on the LC panel assembly 300 and includes a temperature sensor 51 . The temperature sensor 51 generates a temperature sensing signal Vs corresponding to the sensed temperature, and outputs the sensing signal Vs to the signal controller 600 .

Referring to FIG. 3, the LC panel assembly 300 is divided into a display area DA and a peripheral area PA. The LC layer 3 is formed on the display area DA. The peripheral area PA is mainly disposed along the edge of the LC panel assembly 300 and is covered by the light shielding part 220 . The temperature sensor 51 of the temperature sensing unit 50 is installed on the peripheral area PA.

As shown in FIG. 3 , four temperature sensors 51 are formed on the LC panel assembly 300 . In the particular embodiment described, two temperature sensors 51 are mounted along one side of the LC panel assembly 300 and the other two temperature sensors 51 are mounted along different sides of the LC panel assembly 300 . However, the present invention does not limit the number and positions of the temperature sensors 51 . For example, there may be more or less than four temperature sensors 51 , and the temperature sensors 51 may be variously configured on the LC panel assembly 300 to sense the temperature of the LC panel assembly 300 .

The signal controller 600 controls the gate driver 400 and the data driver 500 based on the temperature sensing signal Vs from the temperature sensing unit 50 .

Realization The respective driving devices 400, 500, 600, and 800 may be implemented as an integrated circuit (IC) chip mounted on the panel assembly 300, may be mounted on a flexible printed circuit board as a tape carrier package (TCP) and attached to the LC The panel assembly 300, or mounted on a separate printed circuit board (PCB). Optionally, the driving devices 400, 500, 600, and 800 may be integrated in the LC panel assembly 300 along the display signal lines G ₁ -G _n and D ₁ -D _m and the TFT switching elements Q. Alternatively, the driving devices 400, 500, 600, and 800 may be implemented as an IC chip, and at least one of them or at least one circuit element included in them may be implemented outside the IC chip.

As described above, the LC panel assembly 300 includes two panels 100 and 200, and the panel 100 having thin film transistors is called a TFT array panel. Since the temperature sensor 51 of the temperature sensing unit 50 is formed on the TFT array panel 100 , the TFT array panel 100 according to an embodiment of the present invention will be described in detail with reference to FIGS. 4 to 7 .

4 is a layout diagram of a TFT array panel for an LCD according to an embodiment of the present invention, FIG. 5 is a cross-sectional view of the LCD shown in FIG. 4 taken along the line V-V, and FIG. 6 is taken along the line VI-VI'-VI" 4 is a cross-sectional view of the LCD shown in FIG. 4, and FIG. 7 is a cross-sectional view of the LCD shown in FIG. 4 taken along line VII-VII.

A plurality of gate lines 121, a temperature sensing line 125, and a plurality of storage electrode lines 131 are formed on an insulating substrate 110 made of a material such as transparent glass or plastic.

The gate line 121 transmits a gate signal and extends substantially in a first direction. Each of the gate lines 121 includes a plurality of gate electrodes 124 and an end portion 129 having a large area for contacting other layers or an external driving circuit.

A gate driving circuit (not shown) for generating a gate signal may be mounted on a flexible printed circuit (FPC) film (not shown), and the gate driving circuit may be attached to the substrate 110 directly mounted on the substrate 110. , or integrated in the substrate 110 . The gate line 121 may be extended to be connected to a driving circuit integrated in the substrate 10 .

The temperature sensing line 125 basically extends in a square wave shape in the lateral direction. When the length of the temperature sensing line 125 increases, the temperature resistance and temperature sensitivity also increase.

The temperature sensing line 125 includes two ends 126 and 127 having a large area for contacting other layers or an external driving circuit on each end thereof. One terminal 126 is used as an input terminal to receive a signal, and the other terminal 127 is used as an output terminal to output a signal.

The storage electrode lines 131 are supplied with a predetermined voltage, and each of the storage electrode lines 131 has a portion extending substantially parallel to the gate lines 121 . A plurality of storage electrodes 133 a and 133 b protrude from a portion of the storage electrode line 131 extending parallel to the gate line 121 . Each of the storage electrode lines 131 is disposed between two gate lines 121, and a portion of the storage electrode lines 131 extending parallel to the gate lines 121 is closer than one of the two adjacent gate lines 121. near another. Each of the storage electrodes 133a and 133b has a fixed end and a free end. The fixed end portion of the storage electrode 133b is wide and connected to a portion of the storage electrode line 131 parallel to the gate line 121 . The fixed end has straight and curved branches extending therefrom. However, specific portions of the storage electrode lines 131 shown therein are not limited to the present invention, and the storage electrode lines 131 may have various shapes and arrangements.

The gate line 121, the temperature sensing line 125, and the storage electrode line 131 include two conductive films having different physical properties. The two conductive films are a lower film and an upper film disposed on the lower film. The lower film is preferably made of low-resistivity metals including Al-containing metals (e.g., Al or Al alloys), Ag-containing metals (e.g., Ag or Ag alloys), and Cu-containing metals (e.g., Cu or Cu alloys) for reduced signal delay or voltage drop. The upper film is preferably made of a material (e.g., a Mo-containing metal (Mo or Mo alloy) having the same good physical, chemical, and electrical contact properties as other materials such as indium tin oxide (ITO), or indium zinc oxide (IZO). , Cr, Ta, or Ti) made. An example of a combination of two films is a lower Al (alloy) film and an upper Mo (alloy) film.

In FIG. 5, for the gate electrode 124, the temperature sensing line 125, and the storage electrode line 131, the lower and upper films are indicated by appended letters p and q, respectively.

In some embodiments, the lower film is made of a good contact material and the upper film is made of a low resistivity material. In this case, the upper film 129q of the end 129 of the gate line 121 and the upper films 126q and 127q of the ends 126 and 127 of the temperature sensing line 125 may be removed to expose the lower films 129p, 126p, and 127p. In addition, the gate line 121, the temperature sensing line 125, and the storage electrode line 131 may include a single layer preferably made of the above-mentioned materials. Alternatively, the gate line 121, the temperature sensing line 125, and the storage electrode line 131 may be made of some other suitable metal or conductor.

Sides of the gate lines 121, the temperature sensing lines 125, and the storage electrode lines 131 are inclined with respect to the surface of the substrate 110 to form an inclination angle ranging from about 30-80 degrees. Preferably, the gate lines 121, the temperature sensing lines 125, and the storage electrode lines 131 are formed by sputtering.

A gate insulating layer 140 preferably made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate line 121 , the temperature sensing line 125 , and the storage electrode line 131 .

A plurality of semiconductor strips 151 (see FIG. 4 ), preferably made of hydrogenated amorphous silicon (abbreviated as "a-Si") or polysilicon, are formed on the gate insulating layer 140 . The semiconductor strip 151 extends in a direction substantially perpendicular to the direction in which the gate lines 121 extend, and widens near the gate lines 121 and the storage electrode lines 131 . Therefore, the semiconductor strip 151 covers a large area of the gate line 121 and the storage electrode line 131 . Each of the semiconductor strips 151 includes a plurality of projections 154 protruding toward the gate electrode 124 .

A plurality of ohmic contact strips 161 and islands 165 are formed on the semiconductor strip 151 . Ohmic contact strips 161 and islands 165 are preferably made of n+ hydrogenated a-Si heavily doped with N-type impurities (eg phosphorus), or made of silicide. Each ohmic contact strip 161 includes a plurality of protrusions 163 , and the protrusions 163 and ohmic contact islands 165 are located in pairs on the protrusions 154 of the semiconductor strip 151 .

The sides of the semiconductor strip 151 and the ohmic contacts 161 and 165 are inclined relative to the surface of the substrate 110 to form an inclination angle preferably in the range of about 30-80 degrees.

A plurality of data lines 171 and a plurality of drain electrodes 175 are formed on the ohmic contacts 161 , 165 and the gate insulating layer 140 .

Although the data line 171 and the gate line 121 are electrically insulated from each other, the data line 171 transmits a data signal and extends substantially parallel to the semiconductor strip 151 to cross the gate line 121 . Each data line 171 also crosses the storage electrode line 131 and passes between the storage electrodes 133a and 133b. Each data line 171 includes a plurality of source electrodes 173 and an end portion 179 . The source electrode 173 partially overlaps the gate electrode 124 and has a substantially crescent shape. The end portion 179 has a large area for contact with other layers or driver circuits. A data driving circuit (not shown) for generating data signals, which may be attached to the substrate 110 , mounted directly on the substrate 110 , or integrated in the substrate 110 , is mounted on the FPC film (not shown). The data line 171 may be extended to be connected to a driving circuit integrated in the substrate 110 .

The drain electrode 175 is separated from the data line 171 and disposed opposite to the source electrode 173 with respect to the gate electrode 124 . Each of the drain electrodes 175 includes a wide end and a narrow end. The wide end portion overlaps the storage electrode line 131 , and the narrow end portion is partially surrounded by the source electrode 173 .

The gate electrode 124, the source electrode 173, the drain electrode 175, and the protrusion 154 of the semiconductor strip 151 form a TFT. The TFT has a channel formed in the protrusion 154 between the source electrode 173 and the drain electrode 175 .

The data line 171 and the drain electrode 175 are preferably made of a refractory metal (eg, Cr, Mo, Ta, Ti, or alloys thereof). However, they may have a multilayer structure including a refractory metal film (not shown) and a low-resistivity film (not shown). An example of a multilayer structure is a two-layer structure including a lower Cr/Mo (alloy) film and an upper Al (alloy) film; and a lower Mo (alloy) film, a middle Al (alloy) film, and an upper Mo (alloy) film three-layer structure. However, without limiting the present invention, the data line 171 and the drain electrode 175 may be made of any suitable metal or conductor.

The data line 171 and the drain electrode 175 have an inclined edge shape, so that the edge sidewalls form an inclined angle of about 30-80 degrees.

The data line 171 and the drain electrode 175 may be formed by sputtering.

The ohmic contacts 161 and 165 are interposed only between the lower layer semiconductor strip 151 and the overlying conductors 171 and 175, and reduce the contact resistance between layers. Although the semiconductor strips 151 are narrower than the data lines 171 in many places, they become wider near the gate lines 121 and storage electrode lines 131 as described above. The widening of the semiconductor strip 151 helps to smooth the surface, thereby reducing the possibility of gate line disconnection. In plan view, the semiconductor stripe 151 covers substantially the same area as the data line 171 and the drain electrode 175 and the lower ohmic contacts 161 and 165 . However, the semiconductor strip 151 also includes some portions not covered by the data line 171 and the drain electrode 175 , for example, a portion between the source electrode 173 and the drain electrode 175 .

A passivation layer 180 is formed on the data line 171 , the drain electrode 175 , and exposed portions of the semiconductor strip 151 . The passivation layer 180 is preferably made of an inorganic or organic insulator, and it may have a flat surface. Examples of inorganic insulators include silicon nitride and silicon oxide. The organic insulator may have photosensitivity and a dielectric constant of less than about 4.0. The passivation layer 180 may include a lower film of an inorganic insulator and an upper film of an organic insulator. The advantage of the double-layer film structure is that it enables the passivation layer 180 to have the insulating properties of an organic insulator, while preventing the exposed portion of the semiconductor strip 151 from being damaged by the organic insulator.

The passivation layer 180 has a plurality of contact holes 182 and 185 for exposing the end portion 179 of the data line 171 and the drain electrode 175, respectively. The passivation layer 180 and the gate insulating layer 140 have a plurality of contact holes. The contact hole 181 exposes the upper film 129q of the end portion 129 of the gate line 121 . The contact holes 186 and 187 expose the upper films 126q and 127q of the end portions 126 and 127 of the temperature sensing line 125, respectively. The plurality of contact holes 183a exposes a portion of the storage electrode line 131 near the fixed end of the storage electrode 133b, and the plurality of contact holes 183b exposes a linear branch of a free end of the storage electrode 133b.

A plurality of pixel electrodes 191 , a plurality of overpasses 83 , and a plurality of contact assistants 81 , 82 , 86 , and 87 are formed on the passivation layer 180 . They are preferably made of transparent conductors (eg, ITO or IZO) or reflective conductors (eg, Ag, Al, Cr, or alloys thereof).

The pixel electrode 191 is physically and electrically connected to the drain electrode 175 through the contact hole 185 such that the pixel electrode 191 receives a data voltage from the drain electrode 175 . According to the received data voltage, the pixel electrode 191 and the common electrode 270 of the color filter panel 200 supplied with the common voltage generate an electric field in the liquid crystal layer. The electric field determines the orientation of liquid crystal molecules (not shown) in the liquid crystal layer 3 disposed between the two panels 100 and 200 . A capacitance called "liquid crystal capacitance" is formed by the pixel electrode 191 and the common electrode 270, which stores an applied voltage after the TFT is turned off.

The pixel electrode 191 overlaps the storage electrode line 131 and the storage electrodes 133a and 133b. The pixel electrode 191, the drain electrode 175 connected thereto, and the storage electrode line 131 form an additional capacitance called "storage capacitance". The storage capacitor increases the voltage storage capacity of the liquid crystal capacitor.

The pixel electrode 191 overlaps the adjacent gate line 121 to increase the aperture ratio.

The contact assistants 81, 82, 86, and 87 are connected to the end 129 of the gate line 121, the ends 126 and 127 of the temperature sensing line 125, and the data line 171 through the contact holes 181, 182, 186, and 187, respectively. 179 of the end. The contact assistants 81, 82, 86, and 87 protect the end portions 129, 126, 127, and 179, and improve adhesion of the end portions 129, 126, 127, and 179 to external devices.

The jumper 83 is formed over the gate line 121 . The jumper 83 is connected to the exposed portion of the storage electrode line 131 and the exposed linear branch of the free end portion of the storage electrode 133b through the contact holes 183a and 183b, respectively. Contact holes 183a and 183b are disposed at both ends of one of the gate lines 121 opposite to each other. The storage electrodes 133a and 133b and the jumper 83 may be used to repair defects of the gate line 121, the data line 171, or the TFT.

The temperature sensing line 125 formed together with the gate line 121 is a resistor having a variable resistance value varying according to temperature. Therefore, the temperature sensing line 125 functions as the temperature sensor 51 .

The temperature sensing line 125 may be formed to have a width a of about 2 mm or less and a length b of about 2 mm or less. Labeled "a" and "b" in Figure 4.

The temperature sensing line 125 is formed using the same metal as that used to form the gate line 121 by sputtering. Because the metal has good surface stability, surface damage of the temperature sensing line 125 seldom occurs, and the possibility of wrong reading of the temperature sensing line 125 is very small.

The temperature sensor shown in FIGS. 4 to 7 is represented by an equivalent circuit diagram shown in FIG. 8 , which will be described in detail later.

FIG. 8 is an equivalent circuit diagram of a temperature sensor according to an embodiment of the present invention.

Referring to FIG. 8, the temperature sensor 51 may be represented as a resistor Rs connected to the driving voltage Vdd and a resistor Rc connected between the temperature sensor 51 and the ground. Resistor Rc is a fixed value resistor.

The temperature sensor 51 is supplied with a driving voltage Vdd from an end 126 of the temperature sensing line 125, and outputs an output signal Vout as a temperature sensing signal Vs through an end 127 connected to a resistor Rc.

The output signal Vout is obtained as follows

[equation 1]

$\mathrm{<span\; class="notranslate">\; Vout</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Rc</span>}}{\mathrm{<span\; class="notranslate">\; Rs.</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; Rc</span>}}\mathrm{<span\; class="notranslate">\; Vdd</span>}$

Rs is expressed as:

$\mathrm{<span\; class="notranslate">\; Rs.</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; WD</span>}}$

And, ρ is expressed as:

ρ=ρ ₀ (1+αT)

Here, ρ is the resistivity of the temperature sensing line 125 , W is the width of the temperature sensing line 125 , L is the length of the temperature sensing line 125 , and D is the thickness of the temperature sensing line 125 . Also, _ρ0 is resistivity at a predetermined temperature (for example, about 20° C.), α is a temperature coefficient of resistance (TCR), that is, a coefficient representing a change in resistance value with respect to a change in temperature, and T is temperature.

The resistivity ρ ₀ and the temperature coefficient α are constant predetermined values, and the width W, length L, and thickness D are determined by design.

As a result, the resistance value of the resistor Rs varies based on the temperature T. Therefore, the voltage of the output signal Vout also changes based on the temperature.

As described above, when designing the temperature sensing line 125 , the width W, length L, and thickness D of the temperature sensing line 125 are defined, and characteristics of the temperature sensing line 125 are at least partially defined according to these dimensions.

When the temperature sensor 51 is made of Al, Cu, Pt, Cr, or Mo, the resistivity ρ ₀ and the temperature coefficient α are shown below.

【sheet】 Metal ρ ₀ (10 ^-8 Ωcm) α(10 ^-4 /k) Al 2.69 42.0 Cu 1.67 43.0 Pt 10.6 39.2 Cr 12.1 - Mo 5 -

In order to obtain good sensitivity and stability of the temperature sensor 51, preferably the temperature coefficient α is large and stable. The temperature sensor 51 is preferably made of a metal having a resistivity p that varies linearly with temperature.

When the temperature sensor 51 is manufactured as the temperature sensing line 125 of FIGS. 4 to 7 , the output signal Vout from the temperature sensor 51 varies according to the temperature T as described below.

9 is a graph of output voltage as a function of temperature measured by a temperature sensor according to an embodiment of the present invention.

The graph of FIG. 9 is generated using the temperature sensing line 125 having a double-layer structure. The lower film contains Al, the upper film contains Mo, the driving voltage Vdd is about 2V, and the resistance value of the resistor Rc is about 1.7KΩ.

As shown in FIG. 9, the output voltage Vout varies linearly with temperature in the range of about -10°C to about 80°C. The temperature sensor 51 having the temperature sensing line 125 has a sensitivity of about 1.83 (mv/° C.). Therefore, the output voltage Vout can be used directly without external signal processing (eg, amplified by an independent amplifier).

The temperature sensing line 125 may be formed of the same layer as the data line 171 or the pixel electrode 191 . The temperature sensing line 125 may have a three-layer structure including a lower Mo (alloy) film, a middle Al (alloy) film, and an upper Mo (alloy) film. However, the temperature sensing line 125 can use any metal with a large temperature coefficient α that produces consistent results across different runs and has a resistivity ρ that varies linearly with temperature T, This metal can be used for the temperature sensing line 125 .

Next, the operation of the LCD will be described in detail.

The signal controller 600 is supplied with RGB image signals R, G, B and input control signals for controlling display of the RGB image signals R, G, B from an external graphics controller (not shown). The input control signals include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock signal MCLK, and a data enable signal DE. The signal controller 600 also receives the temperature sensing signal Vs from the temperature sensing unit 50 .

The signal controller 600 generates gate control signals CONT1 and data control signals CONT2 and processes image signals R, G, B to adapt them to the operation of the panel assembly 300 based on the input control signals. Subsequently, the signal controller 600 provides the gate driver 400 with the gate control signal CONT1 , and provides the data driver 500 with the processed image signal DAT and the data control signal CONT2 . The signal controller 600 controls the gate driver 400 and the data driver 500 based on the temperature sensing signal. The operation of the signal controller 600 will be described in detail later.

The gate control signal CONT1 includes a scan start signal STV for instructing to start scanning and at least one clock signal for controlling the output timing of the gate-on voltage Von. The gate control signal CONT1 may further include an output enable signal OE for defining a duration of the gate-on voltage Von.

The data control signal CONT2 includes a horizontal synchronization start signal STH for notifying the start of data transfer of a group of pixels, a load signal LOAD for instructing application of data voltages to the data lines D ₁ -D _m , and a data clock signal HCLK. The data control signal CONT2 may further include an inversion signal RVS (relative to the common voltage Vcom) for inverting the polarity of the data voltage.

The data driver 500 receives image data DAT packets of a group of pixels from the signal controller 600 in response to the data control signal CONT2 from the signal controller 600 . The data driver 500 converts the image data DAT into analog data voltages selected from gray voltages provided by the gray voltage generator 800 and applies the data voltages to the data lines D ₁ -D _m .

The gate driver 400 applies the gate-on voltage Von to the gate lines G ₁ -G _n in response to the gate control signal CONT1 from the signal controller 600 . The switching element Q is turned on in response to the gate-on voltage Von applied to the gate lines _G1 - _Gn . The data voltages applied to the data lines _D1 - _Dm are supplied to the pixels through the turned-on switching elements Q.

The difference between the data voltage and the common voltage Vcom is represented as a voltage across the LC capacitor Clc, which is sometimes referred to as a pixel voltage. The orientation of the LC molecules in the LC capacitor Clc depends on the magnitude of the pixel voltage, and the orientation of the molecules determines the polarization of the light passing through the LC layer 3 . Polarizers convert light polarization into light transmission.

By repeating this process in units of horizontal periods (represented by "1H" and equal to one period of the horizontal period signal Hsync and the data enable signal DE), the gate-on voltage Von is sequentially supplied to all gate lines G ₁ -G _n . Therefore, the data voltage is applied to all the pixels. When one frame ends and the next frame starts, the inversion control signal RVS applied to the data driver 500 is controlled so that the polarity of the data voltage is inverted (referred to as 'frame inversion'). Alternatively, the inversion control signal RVS may also be controlled so that the polarity of the data voltage flowing into the data lines is inverted within one frame (for example, row inversion and dot inversion). Alternatively, the polarity of the data voltages in one packet is reversed (for example, column inversion and dot inversion).

As described above, the elements of the driving circuit or the operating characteristics of the liquid crystal vary widely depending on the temperature of the LCD. Therefore, it is also necessary to adjust the compensating operation based on the temperature of the LCD by considering a wide range of changes. Examples of compensation operations are DCC (Dynamic Capacitance Compensation) and adjustment operations of the magnitude of the gate-on voltage Von.

Since the characteristics of liquid crystals change according to temperature, the response time of liquid crystals also changes. In the DCC control for improving the liquid crystal response time, the signal controller 600 controls the DCC based on the temperature determined by the temperature sensing signal Vs.

The threshold voltage of the switching element Q changes according to temperature. Accordingly, the signal controller 600 changes the magnitude of the reference voltage for generating the gate-on voltage Von based on the temperature. Thus, the gate-on voltage is adjusted so that the temperature-dependent period during which the switching element Q is turned on is appropriately controlled.

In the compensation operation described above, the DCC of the signal controller 600 will be described with reference to FIG. 10 .

FIG. 10 is a block diagram of a signal controller according to another embodiment of the present invention.

Referring to FIG. 10 , the signal controller 600 includes a frame memory 611 , a look-up table unit 612 , and a signal output unit 613 . The frame memory 611 is supplied with an image signal G _n of one frame for each pixel (hereinafter, referred to as “current image signal”). The signal output unit 613 is connected to the frame memory 611 and the look-up table unit 612, and supplies the temperature sensing signal Vs and the current image signal to the signal output unit.

The frame memory 611 applies an image signal G _n−1 of a previous frame (hereinafter, referred to as “previous image signal”) for a pixel to the lookup table unit 612 and the signal output unit 613 . The current image signal _Gn received from the external device is stored.

The lookup table unit 612 includes a plurality of lookup tables LU1-LUp. Each look-up table LU1-LUp stores a corrected image signal having a value defined based on the temperature sensing signal Vs as a function of the previous image signal Gn _-1 and the current image signal _Gn . The corrected image signal is defined based on experimental results in consideration of the temperature of the LC panel assembly 300, the difference between the previous image signal and the current image signal, and the like. The difference between the corrected image signal and the previous image signal is larger than the difference between the current image signal before correction and the previous image signal.

Next, the operation of the signal controller 600 will be described in detail.

The signal controller 600 determines the temperature based on the temperature sensing signal Vs from the temperature sensing unit 50, and selects one of the look-up tables LU1-Lup according to the determined temperature. For example, when the determined temperature falls within the first range, the signal output unit 613 may select the first look-up table LU1, and when the determined temperature falls within the p-th range, the signal output unit 613 may select the p-th look-up table Lup.

The signal output unit 613 selects a corresponding corrected image signal based on the external current image signal G _n and the previous image signal G _n−1 from the frame memory 611 . The selected corrected image signal is applied to the data driver 500 as an image signal DAT.

Therefore, the magnitude of the data voltage applied to each pixel is larger or smaller than the magnitude of the target data voltage defined as the current image signal. Thus, the amount of time required to reach the ideal pixel voltage can be reduced.

In some embodiments, the look-up table may only store corrected image signals (hereinafter, referred to as “reference corrected image signals”) relative to a predetermined number of previous image signals (hereinafter, referred to as “reference previous image signals”) with predetermined intervals. signal") and a predetermined number of corrected image signals (hereinafter, referred to as "reference current image signals") respectively corresponding to the reference previous image signal, instead of the previous image signal G _n-1 and the current image signal G _n Correct the image signal. A further corrected image signal is calculated by interpolation using the reference previous image signal and the reference current image signal. By doing so, the size of the lookup table is reduced.

A temperature sensor according to an embodiment of the present invention may be used in a plasma display panel (PDP) or an organic light emitting display OLED and LCD to sense the temperature of the display panel.

The present invention results in stable temperature detection due to the use of metals instead of semiconductors with high optical reactivity to fabricate the temperature sensor. Light effects during temperature detection are minimized due to the absence of semiconductors with high optical reactivity.

In the present invention, a separate light shielding film for shielding incident light is not required. Therefore, the manufacturing process and structure of the temperature sensor and the overall structure are simplified.

Because the temperature sensor is directly integrated in the LC panel assembly together with the gate line and the data line, the temperature measured by the temperature sensor is substantially close to the actual temperature of the LC layer, thereby improving the accuracy of temperature compensation. This increase in precision is achieved without a substantial increase in production costs.

In addition, an image signal is applied to the pixel based on a sensed temperature similar to the temperature of the LC layer. Accordingly, the response time of the liquid crystal is shortened, thereby improving the image quality of the display device. By integrating the temperature sensor directly into the LC panel assembly, production costs are reduced since no separate temperature sensor needs to be externally mounted on the LCD.

Since the temperature sensor is made of light-insensitive metal, an error rate due to incident light from the outside is reduced. Since a separate structure for shielding incident light is not required, the manufacturing process and structure of the temperature sensor are simplified.

Furthermore, as mentioned above, since the temperature sensor is fabricated using metal wires with good surface stability, the chances of breakage and false readings are reduced.

A flicker adjustment system using the above-described temperature sensor according to another embodiment of the present invention will be described with reference to FIGS. 11 to 16B.

11 is a block diagram of an LCD according to another embodiment of the present invention, FIG. 12 is a schematic diagram of a flicker adjustment system for an LCD according to another embodiment of the present invention, and FIG. 13 shows a schematic diagram of an LCD according to another embodiment of the present invention. A block diagram of a flicker adjustment system, and FIG. 14 shows an example of a circuit diagram of a temperature sensing unit and a common voltage generator shown in FIG. 13 .

The LCD shown in FIG. 11 is substantially the same as the LCD shown in FIG. 1, and thus all redundant descriptions will be omitted. Unlike the LCD of FIG. 1 , the LCD of the present embodiment includes a common voltage generator 700 and a digital variable resistor (DVR) 750 for generating a common voltage Vcom. The common voltage generator 700 transmits the common voltage Vcom to the LC panel assembly 300 for supplying and connecting to the temperature sensing unit 50 . The temperature sensor may be part of the temperature sensing unit 50 shown in FIG. 3 . That is, this part can provide the temperature sensing signal Vs to the signal controller, and the remaining part can be connected between the DVR 750 and the common voltage generator 700.

The DVR 750 generates a reference voltage for supplying to the temperature sensing unit 50 based on a value stored in its memory (not shown), and may be an integrated circuit.

The common voltage generator 700 generates a common voltage Vcom based on the compensation voltage Vc from the temperature sensing unit 50 and receives the common voltage Vcomf output from the LC panel assembly 300 . In this case, the reference voltage Vref for reducing LCD flicker can be stored in the memory of the DVR 750.

Referring to FIGS. 12 to 14, a flicker adjustment system according to another embodiment of the present invention includes an LCD 11, a camera 21, and a computer 31.

The LCD 11 is finally tested for flickering and connected to a computer 31.

The photographing device 21 is also connected to the computer 31, and it photographs a part or the entire screen of the LCD 11. The photographing device 21 measures the brightness of the screen, thereby converting the measured brightness into an electrical signal. In some embodiments, the electrical signal may be a voltage transmitted to the computer 31 .

The computer 31 is connected to the DVR 750 of the LCD 11 , and the DVR 750 outputs a reference voltage according to a control signal CONT3 from the computer 31 . The computer 31 and the DVR 750 are interconnected with each other through the I ² C interface.

The temperature sensing unit 50 includes a temperature sensor Rs and a fixed value resistor Rc shown in FIG. 8 , and also includes a fixed value resistor R1 for receiving a reference voltage Vref. In this case, it is worth noting that the positions of the temperature sensor Rs and the constant value resistor Rc with respect to the driving voltage Vdd and the ground voltage GND in the temperature sensing unit 50 are opposite to those of the embodiment of FIG. 8 . This change in position causes the output voltage Vout in FIG. 9 to become higher.

The common voltage generator 700 may include an operational amplifier OP, which may be a differential amplifier. The non-inverting input (+) of the operational amplifier OP is connected to node N. The inverting input terminal (-) is connected to the feedback common voltage Vcomf through the resistor R2, and connected to the output terminal through the resistor R3.

The voltage input to the non-inverting input terminal of the operational amplifier OP, that is, the voltage of the node N is determined by the principle of superposition as follows.

[equation 2]

$\mathrm{<span\; class="notranslate">\; Vc</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="Rth"\; filenames="H06199330620060720E000011.png,H06199330620060720E000021.png"\; state="\{\{state\}\}">Rth</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; Rc</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="Rth"\; filenames="H06199330620060720E000011.png,H06199330620060720E000021.png"\; state="\{\{state\}\}">Rth</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; Vdd</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; Rth</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="R"\; filenames="H06199330620060720E000011.png,H06199330620060720E000021.png"\; state="\{\{state\}\}">R</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; Rth</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; Vref</span>}$

Here, Rth1 is the equivalent resistance value of the resistors R1 and Rc with respect to the 0V voltage Vref, and Rth2 is the equivalent resistance value of the resistors Rs and Rc with respect to the 0V voltage Vdd.

As described above, the common voltage generator 700 generates the common voltage Vcom based on the temperature compensation voltage Vc instead of the reference voltage Vref, which is received from the DVR 750.

Therefore, although the characteristics of the LCD 11 may vary depending on the temperature, flickering of the LCD 11 can be reduced when this variation is taken into consideration.

15 is a graph showing the resistance characteristics depending on the temperature detected by a temperature sensor according to another embodiment of the present invention, and FIGS. The graph of the common voltage.

Referring to FIG. 15, the resistance value of the temperature sensor 51 is linearly proportional to an increase in temperature.

Therefore, since the temperature sensor 51 has a resistance value Rt for the temperature Tt of the LCD 11 when the final test is performed, and has a resistance value Rn for the temperature Tn when the user uses it, an increase in temperature during use will cause a decrease in the compensation voltage Vc Increase. As a result, as shown in FIG. 16A, the common voltage Vcom increases.

The data voltage generated by the data driver 500 also increases in proportion to the temperature. Since in the conventional device, the existing common voltage is constant regardless of the temperature as shown in FIG. 16B, flicker may appear on the LCD when the temperature increases.

However, according to the present invention, the common voltage Vcom increases with temperature. The common voltage Vcom is located at the center of the data voltage to prevent flicker.

The output signal is used directly without signal processing (eg, amplified by a separate amplifier).

Furthermore, undesired flicker depending on temperature can be precisely controlled by adjusting the common voltage based on a signal obtained from using a temperature sensor.

While the present invention has been described in detail with reference to preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments, but on the contrary covers various modifications and equivalents included within the spirit and scope of the appended claims.

Claims (4)

1. LCD comprises:

Pixel;

First signal wire is connected to described pixel;

The secondary signal line is connected to described pixel, and intersects with described first signal wire; And

The temperature sensing line separates with described first and second signal wires, and wherein said temperature sensing line is formed on the layer identical with described first signal wire or described secondary signal line,

Wherein said temperature sensing line comprises the first end that driving voltage is provided and the second end of output signal output, and

Wherein said the second end is connected to fixed value resistance, and described fixed value resistance is connected to earth terminal.

2. LCD according to claim 1 also comprises based on the signal controller from the demonstration of the described pixel of signal controlling of described temperature sensing line.

3. LCD according to claim 2 also comprises:

Data driver is used for converting the picture signal that is corrected from described signal controller to data-signal, described data-signal is applied to described first signal wire; And

Gate drivers, the gating signal that is used for being used to control described pixel is applied to described secondary signal line.

4. LCD according to claim 3, wherein, described signal controller receives the picture signal from external device (ED), and based on the described picture signal of previous picture signal correction, the picture signal that is corrected with output, and according to the correction from the described picture signal of signal change of described temperature sensing line.

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