Patent Publication Number: US-7719634-B2

Title: Sensor, thin film transistor array panel, and display panel including the sensor

Description:
This application claims priority to Korean Patent Application No. 10-2005-0004879, filed on Jan. 19, 2005 and all the benefits accruing therefrom under 35 U.S.C. §119, and the contents of which in its entirety are herein incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   (a) Field of the Invention 
   The present invention relates to a sensor, a thin film transistor array panel including the sensor, and a display panel including the sensor. More particularly, the present invention relates to an improved temperature sensor, a thin film transistor array panel including the temperature sensor, and a display panel including the temperature sensor. 
   (b) Description of the Related Art 
   Display devices used for monitors of computers and television sets generally include self-emitting display devices such as organic light emitting displays (“OLEDs”), vacuum fluorescent displays (“VFDs”), field emission displays (“FEDs”), and plasma panel displays (“PDPs”), and non-emitting display devices such as liquid crystal displays (“LCDs”) requiring an external light source. 
   An LCD includes two panels provided with field-generating electrodes and a liquid crystal (“LC”) layer having dielectric anisotropy interposed therebetween. The field-generating electrodes supplied with electric voltages generate an electric field across the LC layer, and the light transmittance of the LC layer varies depending on the strength of the applied field, which can be controlled by the applied voltages. Accordingly, desired images are displayed by adjusting the applied voltages. 
   The light for an LCD may be provided by lamps equipped at the LCD or may instead be natural light. 
   Since optical characteristics of the liquid crystal within the LC layer are changed based on temperature, a temperature variation of the LCD has to be considered for improving reliability thereof. 
   That is, since the optical characteristics such as refractive index, dielectric constant, coefficient of elasticity, and viscosity of the liquid crystal are in inverse proportion to thermalization energy of liquid crystal molecules within the LC layer, values of the optical characteristics decrease as the temperature of the liquid crystal becomes higher. Thus, to optimize a state of the liquid crystal for good driving of the LCD, the temperature variation of the LCD due to internal heating and temperature within the ambient environment has to be detected. 
   A temperature sensor is disposed on a printed circuit board (“PCB”) mounted with a plurality of driving circuits to detect a temperature variation of the LCD. However, the PCB is generally disposed on a rear side of the LCD, on which the lamps and electric elements generating heat are disposed, instead of a front side thereof, on which the LC layer is installed, adjacent to the outside. Thus, the temperature sensor detects a temperature at the rear side which has a large temperature deviation caused by the heat. As a result, since the detected temperature by the temperature sensor has a large difference with respect to a temperature of the LC layer, temperature compensation of the LCD based on the temperature of the LC layer is not precisely achieved. In addition, since the temperature sensor is separately installed on the PCB, design redundancy of the LCD and manufacturing cost are increased. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention solves the problems of conventional techniques. 
   In an exemplary embodiment of the present invention, a sensor is provided, which includes a sensor control electrode formed on a substrate, an insulating layer formed on the sensor control electrode, a semiconductor formed on the insulating layer, an ohmic contact formed on the semiconductor, a sensor input electrode and a sensor output electrode formed on the ohmic contact, and a passivation layer formed on the sensor input electrode and the sensor output electrode. 
   The insulating layer may be further formed on portions of the substrate not covered by the sensor control electrode. The passivation layer may be further formed on portions of the semiconductor not covered by the ohmic contact, sensor input electrode, or sensor output electrode, and on portions of the insulating layer not covered by the semiconductor, ohmic contact, sensor input electrode, and sensor output electrode. 
   The sensor input electrode may include a plurality of first branches spaced by a predetermined distance and formed as a comb, and the sensor output electrode includes a plurality of second branches spaced by a predetermined distance and formed as a comb, wherein the first branches are engaged with the second branches through the semiconductor, respectively. The first branches may be alternately arranged with respect to the second branches. 
   The sensor may include a first signal line connected to the sensor control electrode, a second signal line connected to the sensor input electrode, and a third signal line connected to the sensor output electrode. The passivation layer may be further formed on the sensor control electrode and may include a first contact hole exposing a portion of the first signal line, a second contact hole exposing a portion of the second signal line, and a third contact hole exposing a portion of the third signal line. 
   The sensor may further include contact assistants connecting the first signal line and second signal line through the first and second contact holes, respectively, and the contact assistants may be made of indium tin oxide (“ITO”) or indium zinc oxide (“IZO”). The second signal line may be connected to a voltage through the second contact hole, and the voltage may be a ground voltage. The third signal line may output a sensing signal, and the semiconductor may be made of amorphous silicon. The sensor may thus be a diode type of temperature sensor. 
   In a further embodiment of the present invention, a sensor is provided, which includes an insulating layer formed on a substrate, a semiconductor formed on the insulating layer, an ohmic contact formed on the semiconductor, a sensor input electrode and a sensor output electrode formed on the ohmic contact, and a passivation layer formed on the sensor input electrode and the sensor output electrode. 
   The insulating layer may be further formed on portions of the substrate not covered by the sensor control electrode. The passivation layer may be further formed on portions of the semiconductor not covered by the ohmic contact, sensor input electrode, or sensor output electrode, and on portions of the insulating layer not covered by the semiconductor, ohmic contact, sensor input electrode, and sensor output electrode. 
   The sensor input electrode may include a plurality of first branches spaced by a predetermined distance and formed as a comb and the sensor output electrode may include a plurality of second branches spaced by a predetermined distance and formed as a comb, wherein the first branches are engaged with the second branches through the semiconductor, respectively. The first branches may be alternately arranged with respect to the second branches. 
   The sensor may further include a sensor input line connected to the sensor input electrode and a sensor output line connected to the sensor output electrode, and the passivation layer may include a first contact hole exposing a portion of the sensor input line and a second contact hole exposing a portion of the sensor output line. 
   The sensor input line may be connected to a voltage through the first contact hole, and the voltage may be a ground. The sensor output line may output a sensing signal. The sensor may thus be a resistor type of temperature sensor. 
   In a still further embodiment of the present invention, a thin film transistor array panel is provided, which includes a gate line and a sensor control electrode formed on a substrate, an insulating layer formed on the gate line and the sensor control electrode, and a semiconductor formed on the insulating layer, an ohmic contact formed on the semiconductor. A data line, a drain electrode, a sensor input electrode, and a sensor output electrode are formed on the ohmic contact, and a passivation layer is formed on the data line, the drain electrode, the sensor input electrode, and the sensor output electrode. 
   The sensor input electrode may include a plurality of first branches spaced by a predetermined distance and formed as a comb and the sensor output electrode may include a plurality of second branches spaced by a predetermined distance and formed as a comb, wherein the first branches are engaged with the second branches through the semiconductor, respectively. 
   The panel may further include a sensor control line connected to the sensor control electrode, a sensor input line connected to the sensor input electrode, and a sensor output line connected to the sensor output electrode. The passivation layer may further be formed on the sensor control electrode and may include a first contact hole exposing a portion of the sensor control line, a second contact hole exposing a portion of the sensor input line, and a third contact hole exposing a portion of the sensor output line, and it may further include a fourth contact hole exposing a portion of the drain electrode. 
   The panel may further include a pixel electrode connected to the drain electrode through the fourth contact hole, and contact assistants connected to the sensor control line, the sensor input line, and the sensor output line through the first, second, and third contact holes, respectively. The contact assistants may be formed on the same layer as the pixel electrode. 
   The sensor control electrode, the sensor input electrode, and the sensor output electrode may be formed on a border of the panel. The sensor control electrode, sensor input electrode, and sensor output electrode form part of a diode type of temperature sensor. 
   In a still further embodiment of the present invention, a thin film transistor array panel is provided, which includes a gate line formed on a substrate, an insulating layer formed on the gate line, a semiconductor formed on the insulating layer, an ohmic contact formed on the semiconductor. A data line, a drain electrode, a sensor input electrode, and a sensor output electrode are formed on the ohmic contact, and a passivation layer is formed on the data line, the drain electrode, the sensor input electrode, and the sensor output electrode. 
   The sensor input electrode includes a plurality of first branches spaced by a predetermined distance and formed as a comb, and the sensor output electrode includes a plurality of second branches spaced by a predetermined distance and formed as a comb, wherein the first branches are engaged with the second branches through the semiconductor, respectively. 
   The panel may further include a sensor input line connected to the sensor input electrode and a sensor output line connected to the sensor output electrode, wherein the passivation layer comprises a first contact hole exposing a portion of the sensor input line and a second contact hole exposing a portion of the sensor output line. The passivation layer may further include a third contact hole exposing a portion of the drain electrode. 
   The panel may further include a pixel electrode connected to the drain electrode through the third contact hole. The panel may further include contact assistants connected to the sensor input line and the sensor output line through the first and second contact holes, respectively, and the contact assistants may be formed on the same layer as the pixel electrode. 
   The sensor input electrode and the sensor output electrode may be formed on a border of the panel. The sensor input electrode and the sensor output electrode form part of a resistor type of temperature sensor. 
   In yet a further embodiment of the present invention, a liquid crystal display panel includes a first panel, a second panel, a liquid crystal layer disposed between the first panel and the second panel, and a temperature sensor formed on a first surface of the first panel, the first surface of the first panel facing the liquid crystal layer. 
   The first panel may be a thin film transistor array panel. The temperature sensor may be formed on a non-display region of the first panel. A plurality of temperature sensors may be formed on the first surface of the first panel. 
   The first panel may include at least one data line, and the temperature sensor may include a sensor input electrode and a sensor output electrode formed within a same layer of the first panel as the data line. The first panel may include a substrate and at least one gate line formed on the substrate, and the temperature sensor may include a sensor control electrode formed on the substrate within a same layer of the first panel as the gate line. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more apparent by describing preferred embodiments thereof in detail with reference to the accompanying drawings, in which: 
       FIG. 1  is a block diagram of an exemplary embodiment of an LCD according to the present invention; 
       FIG. 2  is an equivalent circuit diagram of an exemplary embodiment of a pixel of an LCD according to the present invention; 
       FIG. 3  is a plan view of an exemplary embodiment of an LCD according to the present invention; 
       FIG. 4  is a layout view of an exemplary embodiment of an LCD according to the present invention; 
       FIG. 5A  is a sectional view of the LCD shown in  FIG. 4  taken along line VA-VA′; 
       FIG. 5B  is a sectional view of the LCD shown in  FIG. 4  taken along line VB-VB′; 
       FIG. 6A  is an equivalent circuit diagram of one exemplary embodiment of a diode type of temperature sensor that may be used in an embodiment of the present invention; 
       FIG. 6B  is a graph showing a characteristic of an output voltage with respect to a temperature variation of the diode type of temperature sensor shown in  FIG. 6A ; 
       FIG. 7A  is an equivalent circuit diagram of one exemplary embodiment of a resistor type of temperature sensor that may be used in an embodiment of the present invention; 
       FIG. 7B  is a graph showing a characteristic of an output voltage with respect to a temperature variation of the resistor type of temperature shown in  FIG. 7A ; 
       FIG. 8A  is a layout view of another exemplary embodiment of a resistor type of temperature sensor according to the present invention; 
       FIG. 8B  is sectional view of the resistor type of temperature sensor shown in  FIG. 8A  taken along line VIIIB-VIIIB′; 
       FIG. 9  is a graph showing an output voltage with respect to a temperature variation in an exemplary embodiment of a diode type of temperature sensor according to the present invention; and 
       FIG. 10  is a graph showing an output voltage with respect to a temperature variation in an exemplary embodiment of a resistor type of temperature sensor according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 
   In the drawings, the thickness of layers and regions are exaggerated for clarity. Like 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. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
   Sensors and thin film transistor (“TFT”) array panels having a sensor according to embodiments of the present invention will be described with reference to the drawings. 
     FIG. 1  is a block diagram of an exemplary embodiment of an LCD according to the present invention,  FIG. 2  is an equivalent circuit diagram of an exemplary embodiment of a pixel of an LCD according to the present invention, and  FIG. 3  is a plan view of an exemplary embodiment of an LCD according to the present invention. 
   Referring to  FIG. 1 , an LCD includes an LC panel assembly  300 , a gate driver  400  and a data driver  500  that are connected to the LC panel assembly, a gray voltage generator  800  connected to the data driver  500 , a temperature sensing unit  50 , and a signal controller  600  controlling the above-described elements. 
   With additional reference to the circuital views of  FIGS. 1 and 2 , the LC panel assembly  300  includes a lower panel  100  as a thin film transistor (“TFT”) panel, an upper panel  200  as a color filter panel, where the panels  100  and  200  face each other, and a liquid crystal layer  3  interposed therebetween. The LC panel assembly  300  further includes a plurality of display signal lines G 1 -Gn and D 1 -Dm and a plurality of pixels connected thereto and arranged substantially in a matrix. 
   The display signal lines G 1 -Gn and D 1 -Dm are provided on the lower panel  100 , and include a plurality of gate lines G 1 -Gn transmitting gate signals (also referred to as “scanning signals”) and a plurality of data lines D 1 -Dm transmitting data signals. The gate lines G 1 -Gn extend substantially in a row direction and are substantially parallel to each other, while the data lines D 1 -Dm extend substantially in a column direction and are substantially parallel to each other. 
   Each pixel includes a switching element Q connected to the display signal lines G 1 -Gn and D 1 -Dm, and an LC capacitor C LC  and a storage capacitor C ST  that are connected to the switching element Q. In an alternative embodiment, the storage capacitor C ST  may be omitted if it is unnecessary. 
   The switching element Q, such as a TFT, is provided on the lower panel  100  and has three terminals including a control terminal connected to one of the gate lines G 1 -Gn, an input terminal connected to one of the data lines D 1 -Dm, and an output terminal connected to the LC capacitor C LC  and the storage capacitor C ST . 
   The LC capacitor C LC  includes a pixel electrode  190 , provided on the lower panel  100 , and a common electrode  270 , provided on the upper panel  200 , as two terminals. The LC layer  3 , interposed between the two electrodes  190  and  270 , functions as a dielectric of the LC capacitor C LC . The pixel electrode  190  is connected to the switching element Q, and the common electrode  270  covers an entire surface, or substantially the entire surface, of the upper panel  200  and is supplied with a common voltage Vcom. Alternatively, the pixel electrode  190  and the common electrode  270  may both be provided on the lower panel  100 , and at least one of the pixel electrode  190  and the common electrode  270  may have shapes of bars or stripes. 
   The storage capacitor C ST  is an auxiliary capacitor for the LC capacitor C LC . The storage capacitor C ST  includes the pixel electrode  190  and a separate signal line (not shown), which is provided on the lower panel  100 , overlaps the pixel electrode  190  via an insulator. The separate signal line is supplied with a predetermined voltage such as the common voltage Vcom. Alternatively, the storage capacitor C ST  includes the pixel electrode  190  and an adjacent gate line called a previous gate line, which overlaps the pixel electrode  190  via an insulator. 
   For color display, each pixel uniquely represents one of three colors such as red, green, and blue colors or sequentially represents the three colors in time, thereby obtaining a desired color. The three colors may be primary colors, or other colors not specifically described herein.  FIG. 2  shows an example in which each pixel includes a color filter  230  representing one of the three colors in an area of the upper panel  200  facing an associated pixel electrode  190 . Alternatively, the color filter  230  may be provided on or under the pixel electrode  190  of the lower panel  100 . 
   As shown in  FIG. 2 , a light blocking film  220 , such as a black matrix for preventing light loss, is formed on the upper panel  200  and has openings in areas corresponding to the pixel electrode  190  or the color filter  230 . 
   A pair of polarizers (not shown) polarizing the light emitted from a light source unit (not shown) is attached on the outer surfaces of the panels  100  and  200  of the panel assembly  300 , respectively. Alternatively, one or more polarizers may be provided. 
   The gray voltage generator  800  generates a plurality of gray scale voltages relating to the brightness of the LCD. The gray voltage generator  800  generates two sets of a plurality of gray voltages related to the transmittance of the pixels, and provides the gray voltages to the data driver  500 . The data driver  500  applies the gray voltages, which are selected for each data line D 1 -Dm, by control of the signal controller  600 , to the data line respectively as a data signal. The gray voltages in one set have a positive polarity with respect to the common voltage Vcom, while those in the other set have a negative polarity with respect to the common voltage Vcom. 
   The gate driver  400  is connected to the gate lines G 1 -Gn of the LC panel assembly  300 , synthesizes the gate-on voltage Von and the gate off voltage Voff input from an external device to generate gate signals having combinations of the gate-on voltage Von and the gate-off voltage Voff for application to the gate lines G 1 -Gn. The gate driver  400  may include a plurality of integrated circuits (“ICs”). 
   The data driver  500  is connected to the data lines D 1 -Dm of the LC panel assembly  300 , applies data voltages selected from the gray voltages supplied from the gray voltage generator  800  to the data lines D 1 -Dm, and may also include a plurality of ICs. 
   The gate driving circuits of the gate driver  400  or the data driving circuit of the data driver  500  may be implemented as an integrated circuit (“IC”) chip mounted on the LC panel assembly  300 , such as in a “chip on glass” (“COG”) type of mounting, or on a flexible printed circuit (“FPC”) film of a tape carrier package (“TCP”) type, which are attached to the LC panel assembly  300 . Alternately, the drivers  400  and  500  may be integrated into the LC panel assembly  300  along with the display signal lines G 1 -G n  and D 1 -D m  and the TFT switching elements Q. 
   The temperature sensing unit  50  includes at least one temperature sensor  51 . The temperature sensor  51  generates a temperature sensing signal Vs corresponding to the temperature sensed by the temperature sensor  51  and outputs the sensing signal Vs to the signal controller  600 . 
   The signal controller  600  controls the gate driver  400  and the data driver  500 . 
   Referring to  FIG. 3 , the LC panel assembly  300  is divided into a display region DR on which the LC layer  3  is formed and a non-display region B. The non-display region B mainly corresponds to the border of the LC panel assembly  300 , adjacent an outermost periphery of the LC panel assembly  300 , and is covered by the light blocking film  220 , such as a black matrix. The temperature sensors  51  of the temperature sensing unit  50  are installed on the non-display region B. As shown in  FIG. 3 , the temperature sensors  51  are installed two by two on an upper and a lower part of the LC panel assembly  300 , respectively. In other words, two temperature sensors  51  are installed on a first border portion of the LC panel assembly  300 , and two temperature sensors  51  are installed on a second border portion of the LC panel assembly  300 , where the first border portion is opposite the second border portion. However, the number of the temperature sensors  51  and the installed positions are not limited to the illustrated embodiment. For example, the temperature sensors  51  may be installed on a left and a right of the LC panel assembly  300  to sense a temperature of the LC panel assembly  300 , and other alternative arrangements and quantities of temperature sensors  51  would also be within the scope of these embodiments. 
   Now, the operation of the LCD will be described in detail. 
   The signal controller  600  is supplied with RGB image signals R, G, and B and input control signals controlling the display thereof such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock signal MCLK, a data enable signal DE, etc., from an external graphic controller (not shown). In response to the input image signals R, G, and B and the input control signals, the signal controller  600  processes the image signals R, G, and B suitably for the operation of the LC panel assembly  300  on the basis of the input control signals and a temperature sensing signals Vs, and generates gate control signals CONT 1  and data control signals CONT 2 . The signal controller  600  then provides the gate control signals CONT 1  to the gate driver  400 , and the processed image signals R′, G′, and B′ and the data control signals CONT 2  to the data driver  500 . 
   The gate control signals CONT 1  include a vertical synchronizing start signal, a scanning start signal STV, for informing the beginning of a frame and having instructions to start scanning, and at least one gate clock signal for controlling the output time of the gate-on voltage Von. The gate control signals CONT 1  may further include an output enable signal OE for defining the duration of the gate-on voltage Von. 
   The data control signals CONT 2  include a horizontal synchronization start signal STH for informing the data driver  500  of the start of data transmission for a group of pixels, a load signal LOAD having instructions to apply the data voltages to the data lines D 1 -Dm, and a data clock signal HCLK. The data control signal CONT 2  may further include an inversion signal RVS for reversing the polarity of the data voltages (with respect to the common voltage Vcom). 
   In response to the data control signals CONT 2  from the signal controller  600 , the data driver  500  receives a packet of the image data DAT, the processed image signals, for the group of pixels from the signal controller  600 , converts the image data DAT into analog data voltages selected from the gray voltages supplied from the gray voltage generator  800 , and applies the data voltages to the data lines D 1 -Dm. 
   The gate driver  400  applies the gate-on voltage Von to the gate lines G 1 -Gn in response to the gate control signals CONT 1  from the signal controller  600 , thereby turning on the switching elements Q connected thereto. The data voltages applied to the data lines D 1 -Dm are supplied to the corresponding pixels through the activated switching elements Q. 
   The difference between the data voltage applied to the pixel and the common voltage Vcom is represented as a charged voltage across the LC capacitor C LC , which is referred to as a pixel voltage. The LC molecules in the LC capacitor C LC  have orientations depending on the magnitude of the pixel voltage, and the molecular orientations determine the polarization of light passing through the LC layer  3 . The polarizer(s) converts the light polarization into light transmittance. 
   By repeating this procedure by a unit of the horizontal period (which is denoted by “1H” and equal to one period of the horizontal synchronizing signal Hsync, the data enable signal DE, and the gate clock signal CPV), all gate lines G 1 -Gn are sequentially supplied with the gate-on voltage Von during a frame, thereby applying the data voltages to all pixels. When the next frame starts after finishing one frame, the inversion control signal RVS, part of the data control signals CONT 2 , applied to the data driver  500  is controlled such that the polarity of the data voltages is reversed (which is referred to as “frame inversion”). The inversion control signal RVS may also be controlled such that the polarity of the data voltages flowing in a data line in one frame is reversed (for example, line inversion and dot inversion), or the polarity of the data voltages in one packet is reversed (for example, column inversion and dot inversion). 
   Now, structures of an exemplary embodiment of a sensor and an exemplary embodiment of an LCD having the sensor according to the present invention will be described with reference to  FIGS. 4 to 5B . 
     FIG. 4  is a layout view of an exemplary embodiment of an LCD according to the present invention,  FIG. 5A  is a sectional view of the LCD shown in  FIG. 4  taken along line VA-VA′, and  FIG. 5B  is a sectional view of the LCD shown in  FIG. 4  taken along line VB-VB′. 
   A plurality of gate lines  121 , a sensor control electrode  126 , a sensor control line  128 , and a plurality of storage electrode lines  131  are formed on an insulating substrate  110  such as transparent glass or other suitable transparent insulating material. 
   The gate lines  121  extend substantially in a transverse direction and are separated from each other and transmit gate signals. The gate lines  121  may extend substantially parallel to each other. Each gate line  121  includes a plurality of projections forming a plurality of gate electrodes  124  and an end portion  129  having a large area for contact with another layer or an external driving circuit. The gate lines  121  may extend to be connected to a driving circuit that may be integrated on the insulating substrate  110 . 
   The sensor control electrode  126  has a substantially rectangular shape having a horizontal side longer than a vertical side, where the horizontal side of the sensor control electrode  126  may extend along the transverse direction of the insulating substrate  110  and the vertical side of the control electrode  126  may extend along a longitudinal direction across the insulating substrate  110 . The sensor control line  128  may extend in the longitudinal direction, with respect to the sensor control electrode  126 . While a specific arrangement of the sensor control electrode  126  is illustrated, the sensor control electrode  126  may be positioned in alternate peripheral areas of the insulating substrate  110  as previously described with respect to  FIG. 3 . The sensor control line  128  includes an end portion having a large area for contact with another layer or an external driving circuit. 
   Each of the storage electrode lines  131  which are separated from the gate lines  121  also extends substantially in the transverse direction and is disposed between two adjacent gate lines  121 . The storage electrode lines  131  are supplied with a predetermined voltage such as the common voltage of the other panel (not shown). 
   The gate lines  121 , the sensor control electrode  126 , the sensor control line  128 , and the storage electrode lines  131  are preferably made of an aluminum Al-containing metal such as Al and an Al alloy, a silver Ag-containing metal such as Ag and an Ag alloy, a copper Cu-containing metal such as Cu and a Cu alloy, a molybdenum Mo-containing metal such as Mo and a Mo alloy, chromium Cr, titanium Ti, or tantalum Ta. The gate lines  121 , the sensor control electrode  126 , the sensor control line  128 , and the storage electrode lines  131  may have a multi-layered structure including two films having different physical characteristics. If a two film structure is employed, one of the two films is preferably made of a low resistivity metal including an Al-containing metal for reducing signal delay or voltage drop in the gate lines  121 , the sensor control electrode  126 , the sensor control line  128 , and the storage electrode lines  131 . The other film is preferably made of a material such as Cr, Mo, a Mo alloy, Ta, or Ti, which has good physical, chemical, and electrical contact characteristics with other materials such as indium tin oxide (ITO) or indium zinc oxide (IZO). Some examples of the combination of the two films that provide an appropriate combination of preferable characteristics include a lower Cr film and an upper Al (Al—Nd alloy) film and a lower Al (Al alloy) film and an upper Mo film. 
   In addition, the lateral sides of the gate line  121 , the sensor control electrode  126 , the sensor control line  128 , and the storage line  131  are tapered, and the inclination angle of the lateral sides with respect to a surface of the substrate  110  is within a range of about 30 to about 80 degrees. 
   A gate insulating layer  140 , preferably made of silicon nitride (SiNx), is formed on the gate lines  121 , the sensor control electrode  126 , the sensor control line  128 , and the storage electrode lines  131  and is also formed on the portions of the insulating substrate  110  not covered by the gate lines  121 , the sensor control electrode  126 , the sensor control line  128 , and the storage electrode lines  131 . 
   A plurality of semiconductor stripes  151 , a plurality of semiconductor islands, and a semiconductor rectangle  155 , preferably made of hydrogenated amorphous silicon (abbreviated to “a-Si”), are formed on the gate insulating layer  140 . Each semiconductor stripe  151  extends substantially in a longitudinal direction, extending generally perpendicularly to the storage electrode lines  131  and the gate lines  121 , and has a plurality of projections  154  branched out toward the gate electrodes  124  and a plurality of protrusions disposed on the storage electrode lines  131 . The semiconductor rectangle  155  is separated from the semiconductor stripes  151  and has a shape substantially similar to that of the sensor control electrode  126 . 
   A plurality of ohmic contact stripes  161  and a plurality of ohmic contact islands  165  are formed on the semiconductor stripes  151 , and a plurality of ohmic contact islands  162  and  164  are formed on the semiconductor rectangle  155 . The ohmic contact stripes  161  and islands  165 ,  162 , and  164  are preferably made of silicide or n+hydrogenated a-Si heavily doped with an n-type impurity. Each ohmic contact stripe  161  has a plurality of projections  163 , and the projections  163  and the ohmic contact islands  165  are located in pairs on the projections  154  of the semiconductor stripes  151 . 
   The ohmic contact islands  162  and  164  are located on the semiconductor rectangle  155 , respectively, and are separated from each other. 
   The lateral sides of the semiconductor stripes  151 , the semiconductor rectangle  155 , and the ohmic contact stripes  161  and islands  165 ,  162 , and  164  are tapered, and the inclination angles thereof with respect to the insulating substrate  110  are preferably in a range between about 30 to about 80 degrees. 
   A plurality of data lines  171 , a plurality of drain electrodes  175 , a sensor input electrode  172 , a sensor input line  176 , a sensor output electrode  174 , and a sensor output line  178  are formed on the ohmic contact stripes  161  and islands  165  and the gate insulating layer  140 . 
   The data lines  171  for transmitting data voltages extend substantially in the longitudinal direction and cross over the gate lines  121  and the storage electrode lines  131 . Each data line  171  has an end portion  179  having a large area for contact with another layer or an external device. A plurality of branches of each data line  171 , which project toward the drain electrodes  175 , form a plurality of source electrodes  173 . 
   The sensor input line  176  substantially extends in a longitudinal direction, such as parallel to the sensor control line  128 , and the sensor input electrode  172  includes a connection portion connected to the sensor input line  176 , a transverse portion extending in the transverse direction substantially perpendicular to the longitudinal direction and connected to the connection portion, and a plurality of branches extending from the connection portion via the transverse portion, the branches extending in the longitudinal direction like a comb. 
   The sensor output line  178  substantially extends in the longitudinal direction, such as parallel to the sensor input line  176  and the sensor control line  128 , and the sensor output electrode  174  includes a connection portion connected to the sensor output line  178 , a transverse portion extending in the transverse direction substantially perpendicular to the longitudinal direction and connected to the connection portion, and a plurality of branches extending from the connection portion via the transverse portion, the branches extending in the longitudinal direction like a comb. 
   The branches of the sensor input electrode  172  and the sensor output electrode  174  are alternately engaged through the semiconductor rectangle  155 . 
   Each set of a gate electrode G  124 , a source electrode S  173 , and a drain electrode D  175  along with a projection  154  of a semiconductor stripe  151  form a TFT having a channel formed in the semiconductor projection  154  disposed between the source electrode S  173  and the drain electrode D  175 . 
   The sensor control electrode  126 , the sensor input electrode  172 , and the sensor output electrode  174  along with the semiconductor rectangle  155  form a sensor transistor for a temperature sensor  51 . The specifications of the sensor transistor are defined by a width W and a length L of the electrodes  126  and  172 , and a thickness T of the semiconductor rectangle  155 . 
   The data lines  171 , the source electrode  173 , the drain electrode  175 , the sensor input line  176 , the sensor input electrode  172 , the sensor output line  178 , and the sensor output electrode  174  are preferably made of a refractory metal including Cr, Mo, TV Ta, or alloys thereof. They may have a multi-layered structure, preferably including a low resistivity film and a good contact film. 
   The semiconductor stripes  151  of the TFT array panel according to this embodiment have almost the same planar shapes as the data lines  171  and the drain electrodes  175  as well as the underlying ohmic contacts  161  and  165 . However, the projections  154  of the semiconductor stripes  151  include some exposed portions, which are not covered with the data lines  171  and the drain electrodes  175 , such as portions located between the source electrodes  173  and the drain electrodes  175 . 
   Similar to the gate lines  121 , the data lines  171 , the source electrode  173 , the drain electrodes  175 , the sensor input line  176 , the sensor input electrode  172 , the sensor output line  178 , and the sensor output electrode  174  have tapered lateral sides, and the inclination angles thereof are in a range of about 30 to about 80 degrees with respect to the insulating substrate  110 . 
   A passivation layer  180  is formed on the data lines  171 , the source electrodes  173 , the drain electrodes  175 , the sensor input line  176 , the sensor input electrode  172 , the sensor output line  178 , the sensor output electrode  174 , and the exposed portions of the semiconductor stripes  151  and semiconductor rectangle  155 , as well as any other exposed portions of the gate insulating layer  140 . 
   The passivation layer  180  is preferably made of a photosensitive organic material having a good flatness characteristic, a low dielectric insulating material such as a-Si:C:O and a-Si:O:F formed by plasma-enhanced chemical vapor deposition (“PECVD”), or an inorganic material such as silicon nitride and silicon oxide. The passivation layer  180  may have a double-layered structure including a lower inorganic film and an upper organic film. 
   The passivation layer  180  has a plurality of contact holes  182 ,  185 ,  186 , and  187  exposing the end portions  179  of the data lines  171 , the drain electrodes  175 , and end portions of the sensor input line  176  and the sensor output line  178 , respectively. The passivation layer  180  and the gate insulating layer  140  also have a plurality of contact holes  181  and  189  exposing the end portions  129  of the gate lines  121  and the end portion of the sensor control line  128 , respectively. 
   A plurality of pixel electrodes  190  and a plurality of contact assistants  81 ,  82 ,  86 ,  87 , and  89 , which are preferably made of IZO or ITO, are formed on the passivation layer  180 . The contact assistants  81 ,  82 ,  86 ,  87 , and  89  are formed with respect to the contact holes formed in the passivation layer  180 . 
   The pixel electrodes  190  are physically and electrically connected to the drain electrodes  175  through the contact holes  185  such that the pixel electrodes  190  receive the data voltages from the drain electrodes  175 . 
   The pixel electrodes  190  supplied with the data voltages generate electric fields in cooperation with the common electrode  270  on the upper panel  200 , which reorient liquid crystal molecules in the liquid crystal layer  3  disposed therebetween. 
   The pixel electrodes  190  may optionally overlap the gate lines  121  and the data lines  171  to increase the aperture ratio. 
   The contact assistants  81 ,  82 ,  86 ,  87 , and  89  are connected to the exposed end portions  129  of the gate lines  121 , the exposed end portions  179  of the data lines  171 , the exposed end portion of the sensor input line  176 , the exposed end portion of the sensor output line  178 , and the exposed end portion of the sensor control line  128  through the contact holes  181 ,  182 ,  186 ,  187 , and  189 , respectively. While not required, the contact assistants  81 ,  82 ,  86 ,  87 , and  89  are preferred to protect the exposed end portions and to complement the adhesiveness of the exposed portion and external devices. 
   The contact assistant  81  plays a part in connecting the end portions  129  of the gate lines  121  and the gate driver  400  when the gate driver  400  to supply gate signals is integrated on the insulating substrate  110 , and may alternatively be omitted. 
   According to another embodiment of the present invention, the pixel electrodes  190  are made of a transparent conductive polymer. For a reflective LCD, the pixel electrodes  190  are made of an opaque reflective metal. In these cases, the contact assistants  81  and  82  may be made of a material such as IZO or ITO different from the pixel electrodes  190 . 
   A size of the temperature sensor  51  integrated along with the gate lines  121  and the data lines  171  upon the insulating substrate  110  and varying an operating state or a resistance value thereof based on the sensed temperature may be about 2 mm×2 mm or less. In addition, the sensor control electrode  126  formed on the substrate  110  functions to block light from a light source (not shown) disposed below a lower part of the LC panel assembly  300 . Such a feature does not limit light transmittance of the LC panel assembly  300 , however, since the positioning of the temperature sensor  51  is generally limited to the non-display region B. 
   Exemplary embodiments of the temperature sensor  51  formed with the gate lines  121  and the data lines  171  on the non-display region B of the LC panel assembly  300  include a diode type of temperature sensor and a resistor type of temperature sensor, as shown in  FIGS. 6A to 7B , in accordance with the connection of the sensor control line  128 , the sensor input line  176 , and the sensor output line  178 , as further described below. 
     FIG. 6A  is an equivalent circuit diagram of an exemplary embodiment of a diode type of temperature sensor when a temperature sensor according to an exemplary embodiment of the present invention is the diode type of temperature sensor, and  FIG. 6B  is a graph showing a characteristic of an output voltage with respect to a temperature variation of the diode type of temperature sensor shown in  FIG. 6A .  FIG. 7A  is an equivalent circuit diagram of an exemplary embodiment of a resistor type of temperature sensor when a temperature sensor according to an exemplary embodiment of the present invention is the resistor type of temperature sensor, and  FIG. 7B  is a graph showing a characteristic of an output voltage with respect to a temperature variation of the resistor type of temperature sensor shown in  FIG. 7A . 
   An exemplary embodiment of when lines  128 ,  176 , and  178  of the temperature sensor  51  are connected as a diode type of temperature sensor will be described with reference to  FIGS. 6A and 6B . 
   Referring to  FIG. 6A , a sensor control line G  128  of the temperature sensor  51  is connected to a sensor output line D  178 , and the sensor input line S  176  of the temperature sensor  51  is connected to a ground GND such that a sensor transistor, that is, the temperature sensor  51 , functions as a diode. 
   At this time, an output voltage V D  from the sensor output line D  178  is represented as:
 
 V   D   =V   dd   −RI   D   [Equation 1]
 
   Here, I D  is a current flowing through the sensor output line D  178 , R is a resistor connected to an exterior of the temperature sensor  51 , and Vdd is an input voltage. 
   At this time, for a voltage between the sensor control line G  128  and sensor input line S  176  and a voltage between the sensor output line D  178  and the sensor input line S  176  by the connection between the sensor control line G  128  and the sensor output line D  178 , the I D  is expressed as: 
   
     
       
         
           
             
               
                 
                   I 
                   D 
                 
                 = 
                 
                   
                     μ 
                     n 
                   
                   ⁢ 
                   
                     C 
                     g 
                   
                   ⁢ 
                   
                     W 
                     L 
                   
                   ⁢ 
                   
                     ( 
                     
                       
                         
                           V 
                           D 
                           2 
                         
                         2 
                       
                       - 
                       
                         
                           V 
                           TH 
                         
                         ⁢ 
                         
                           V 
                           D 
                         
                       
                     
                     ) 
                   
                 
               
             
             
               
                 [ 
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   2 
                 
                 ] 
               
             
           
         
       
     
   
   Here, μ n  is electron mobility depending on a temperature variation, Cg is capacitance of the sensor input electrode  172 , W is a channel width, L is a channel length, where W and L are measured such as shown in  FIG. 4 , and V TH  is a threshold voltage. 
   The electron mobility μ n  is represented as: 
   
     
       
         
           
             
               
                 
                   μ 
                   n 
                 
                 = 
                 
                   
                     μ 
                     0 
                   
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     
                       
                         N 
                         C 
                       
                       ⁢ 
                       kT 
                     
                     n 
                   
                   ⁢ 
                   
                     e 
                     
                       
                         - 
                         
                           E 
                           a 
                         
                       
                       / 
                       kT 
                     
                   
                 
               
             
             
               
                 [ 
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   3 
                 
                 ] 
               
             
           
         
       
     
   
   Here, μ 0  is extended state electron mobility, Nc is a state density at mobility edge, k is a Boltzmann constant, T is a temperature (K), n is total electron density, and Ea is activation energy. In one embodiment, μ 0  is ˜6[cm 2 /vs], Nc is ˜2×10 21 [cm 2 /eV], k is 1.3805×10 −23 [J/K], and Ea is 0.13[eV]. 
   As a result, with reference to [Equation 1] to [Equation 3], the output voltage V D  is varied based on a temperature variation. 
   The output voltage V D  of the temperature sensor  51  having the equivalent circuit shown in  FIG. 6A  is linearly varied as a temperature is changed, as shown in  FIG. 6B . 
   An exemplary embodiment of when lines  128 ,  176 , and  178  of the temperature sensor  51  are connected as a resistor type of temperature sensor will be described with reference to  FIGS. 7A and 7B . 
   As shown in  FIG. 7A , a sensor control line G  128  is not supplied with any signals, a sensor input line S  176  is connected to a ground GND through a resistor Rc, and a sensor output line D  178  is supplied with an externally applied driving voltage Vdd. In this embodiment, since the sensor control line G  128  is not supplied with any signals, a temperature sensor  51 , that is, a sensor transistor, functions as a resistor Rs. 
   An output voltage Vout from the temperature sensor  51 , that is, a sensor transistor, is represented as: 
   
     
       
         
           
             
               
                 Vout 
                 = 
                 
                   
                     Rc 
                     
                       Rs 
                       + 
                       Rc 
                     
                   
                   ⁢ 
                   Vdd 
                 
               
             
             
               
                 [ 
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   4 
                 
                 ] 
               
             
           
         
       
     
   
   Rs is expressed as: 
                 Rs   =     ρ   ⁢           ⁢     L   WD                               
and σ is expressed as:
 
   
     
       
         
           σ 
           = 
           
             
               ne 
               ⁢ 
               
                   
               
               ⁢ 
               
                 μ 
                 n 
               
             
             = 
             
               1 
               ρ 
             
           
         
       
     
   
   Here, e is carrier capacitance amount. 
   As described above, since the electron mobility μ n  is represented as [Equation 3], the output voltage Vout is varied based on a temperature variation. 
   The output voltage Vout with respect to a temperature variation is varied as shown in  FIG. 7B . As shown in  FIG. 7B , though the output voltage Vout of the resistor type of temperature sensor is nonlinearly varied, the sensitivity of the temperature sensor  51  on the basis of characteristics of a resistor is good. 
   In the resistor type of temperature sensor, since the sensor control line G  128  is not supplied with any signal, a sensor control line G  176  and a sensor control electrode  126  may be unnecessary. 
   Another exemplary embodiment of a resistor type of temperature sensor according to the present invention will be described with reference to  FIGS. 8A and 8B . A structure of an LCD including the resistor type of temperature sensor may be the same as that shown in  FIGS. 4 and 5A  and is therefore omitted. 
     FIG. 8A  is a layout view of an exemplary embodiment of a resistor type of temperature sensor according to the present invention and  FIG. 8B  is a sectional view of the resistor type of temperature sensor shown in  FIG. 8A  taken along the VIIIB-VIIIB′. 
   As shown in  FIGS. 8A and 8B , a structure of another exemplary embodiment of a resistor type of temperature sensor according to the present invention is similar to that shown in  FIGS. 4 and 5A  except that a sensor control electrode  126  and a sensor control line  128  are not formed. 
   That is, a gate insulating layer  140  is formed on an insulating substrate  110  (with no sensor control electrode  126  and sensor control line  128  present), and a semiconductor rectangle  155 , having horizontal sides longer than vertical sides, is formed on the gate insulating layer  140 . A plurality of ohmic contacts  162  and  164  are formed on the semiconductor rectangle  155 . In addition, a sensor input line  176 , a sensor input electrode  172 , a sensor output electrode  174 , and a sensor output line  178  are formed on the ohmic contacts  162  and  164  and the gate insulating layer  140 . 
   A passivation layer  180  is formed on the sensor input line  176 , the sensor input electrode  172 , the sensor output electrode  174 , and the sensor output line  178 , as well as on any exposed portions of the gate insulating layer  140  and the semiconductor rectangle  155 . The passivation layer  180  has a plurality of contact holes  186  and  187  exposing end portions of the sensor input line  176  and the sensor output line  178 , respectively. 
   Contact assistants  86  and  87  may be formed on the passivation layer  180  in combination with the contact holes  186 ,  187 , respectively. 
   As described above, a resistor type of temperature sensor is designed without the sensor control line  128  and the sensor control electrode  126  since they are not supplied with a signal. 
   For a diode type of temperature sensor and a resistor type of temperature sensor according to embodiments of the present invention, exemplary graphs of output voltages actually outputted therefrom with respect to a temperature variation are shown in  FIGS. 9 and 10 , respectively. 
   For exemplary purposes only, in  FIGS. 9 and 10 , a driving voltage Vdd is about 5V, and W/L is 3200/4.5. In  FIG. 9 , a resistance value of the resistor R is about 620 kΩ , and in  FIG. 10  a resistance value of the resistor Rc is about 2 kΩ . 
   As shown in  FIGS. 9 and 10 , the range of the sensed temperature of an LCD was about −20° C. to 80° C. In  FIG. 9 , temperatures were sensed by a unit of about 10° C., and in  FIG. 10 , temperatures were sensed by a unit of about 2.5° C. In  FIG. 9 , a voltage variation difference ΔV D  is about 1.31V and in  FIG. 10 , a voltage variation difference ΔV out  is about 4.37V. Thus, since dynamic sensibility of the output voltages from the temperature sensors is large, the output voltages are directly used without separate signal processing such as filtering, amplifying, and so on. 
   The exemplary embodiments of temperature sensors according to the present invention sense an exact temperature corresponding to a temperature variation of an LC layer since the temperature sensors are directly integrated in the LC panel assembly along with the gate lines and the data lines. 
   According to the present invention, a temperature sensor is directly integrated in an LCD for sensing a temperature of the LCD, and thereby the temperature is exactly sensed without a large increment of a manufacturing cost. In addition, the controlling of a display device is achieved based on the exactly sensed temperature of the display device, and thereby an image quality of the display device is improved. The design is improved and manufacturing cost is decreased since a separate temperature sensor to be externally installed on the LCD is unnecessary. 
   Moreover, since driving characteristics of a temperature sensor are changed by changing a connection of the lines thereof and a temperature sensor having characteristics suitable for a display device and circumference environment thereof is realized, the driving efficiency of the temperature sensor and the display device is improved. 
   Additionally, since the size of an area of the temperature sensor contacting the surface of an LCD is increased due to the comb shape, while maintaining a small size of the temperature sensor, reliability of sensing is improved and additional circuits are unnecessary. 
   While the present invention has been described in detail with reference to the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.