WO2015023006A1 - Display device of thin film transistor with touch sensor and method of manufacturing the same - Google Patents

Display device of thin film transistor with touch sensor and method of manufacturing the same Download PDF

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Publication number
WO2015023006A1
WO2015023006A1 PCT/KR2013/007239 KR2013007239W WO2015023006A1 WO 2015023006 A1 WO2015023006 A1 WO 2015023006A1 KR 2013007239 W KR2013007239 W KR 2013007239W WO 2015023006 A1 WO2015023006 A1 WO 2015023006A1
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Prior art keywords
display device
gate insulating
insulating film
space part
sensing space
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PCT/KR2013/007239
Other languages
French (fr)
Inventor
Moon Hyo Kang
Ji Ho Hur
Ki Joong Kim
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Silicon Display Technology
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Priority to PCT/KR2013/007239 priority Critical patent/WO2015023006A1/en
Publication of WO2015023006A1 publication Critical patent/WO2015023006A1/en

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0412—Digitisers structurally integrated in a display
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • G06F3/0445—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
    • G06F3/0447—Position sensing using the local deformation of sensor cells
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2203/00—Indexing scheme relating to G06F3/00 - G06F3/048
    • G06F2203/041—Indexing scheme relating to G06F3/041 - G06F3/045
    • G06F2203/04103—Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices

Definitions

  • Embodiments of the present invention relate to a way to perform highly sensitive touch sensing using a thin film transistor.
  • a liquid crystal display device with a touch screen is composed of: a color filter substrate including a plurality of color filters; a thin film transistor substrate including a plurality of pixels; and a polarizing plate each attached to the color filter substrate and the outside of the thin film transistor substrate.
  • the liquid crystal display device equipped with the touch screen uses a method of applying a touch signal in such a manner that when a substrate is pressed, a column spacer is pressed by an elastic force of the column spacer to come into contact with a lower plate.
  • the liquid crystal display device equipped with the touch screen is configured so that an upper plate, namely, the color filter substrate can be pressed even by a small force by reducing the number of column spacers within a range allowed by the uniformity of cell gaps.
  • a touch may be performed by applying a pressure ranging from 80 to 100 gf/cm 2
  • a touch may be performed by applying a pressure ranging from 350 to 400gf/cm 2 . Accordingly,even in the case of the plane touch mode, there is a need to improve the touch sensitivity in the same level as that of the point touch mode.
  • An aspect of embodiments of the present invention provides a display device of a thin film transistor with a touch sensor which is capable of forming through a simple manufacturing process because a touch can be sensed using a gate insulating film, which constitutes the thin film transistor, without a need to use a separate device or an additional deposited film.
  • Another aspect of embodiments of the present invention provides a display device of a thin film transistor with a touch sensor which can easily sense a touch depending on a variation in volume of a space formed between a gate electrode and a second gate insulating film even through pressure applied to a display panel is not large, and a method of manufacturing the same.
  • Still another aspect of embodiments of the present invention provides a display device of a thin film transistor with a touch sensor which can easily sense a touch using a current value which is changed by pressure applied to a display panel by the touch, and a method of manufacturing the same.
  • a display device of a thin film transistor with a touch sensor including: a gate electrode formed on a first substrate; a gate insulating film formed on the first substrate and the gate electrode; and a sensing space part formed by patterning an inner portion of the gate insulating film.
  • the gate insulating film in which the sensing space part is formed may composed of a first gate insulating film formed on the first substrate to cover the gate electrode, and a second gate insulating film formed to cover the first gate insulating film.
  • the touch sensor may sense a touch as a volume of the sensing space part is changed by pressure applied to the sensing space part.
  • a touch can be sensed using the gate insulating film, which constitutes the thin film transistor, without a need to use a separate element or an additional deposition film, a manufacturing process is simple.
  • the pressure applied to the display panel is not large, a touch can be easily sensed depending on a variation in volume of a space formed between the gate electrode and a second gate insulating film.
  • a touch can be easily sensed using a current value which is changed by pressure applied to the display panel by the touch.
  • FIG. 1 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor according to one embodiment
  • FIG. 2 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor in a case where a touch is conducted;
  • FIG. 3 is an equivalent circuit view illustrating the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention
  • FIG. 4 is an equivalent circuit view illustrating a display device of a thin film transistor with a touch sensor according to another embodiment of the present invention
  • FIG. 5 is a schematic diagram illustrating a display device of a thin film transistor with a touch sensor having a pixel circuit depending on an active matrix method
  • FIG. 6 is flow chart illustrating a method of manufacturing the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention.
  • the gist of embodiments of the present invention is to provide a display device having a touch sensor which is configured such that a sensing space part is formed in a gate insulating film itself, which constitutes an thin film transistor, without a need to form a separate element so that a touch can be sensed, thereby improving the efficiency of a manufacturing process, and even though pressure applied to a display panel is not large, the touch can be easily sensed depending on a variation in volume of a space formed between a gate electrode and a second gate insulating film.
  • FIG. 1 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor according to one embodiment
  • a display device of a thin transistor with a touch sensor has the touch sensor including: a gate electrode 10 formed on a first substrate 100; a gate insulating film formed on the first substrate 100 and the gate electrode 10; and a sensing space part 30 formed in an inner portion of the gate insulating film. That is, the display device is characterized by implementing a structure in which a space area (the sensing space part) of a vacant structure is provided in the inner portion of the gate insulating film.
  • the gate insulating film may have a structure which is implemented as an independent one layer.
  • a configuration in which the sensing space part is formed by two insulating film layers will be explained as an example. That is, the sensing space part 30 according to the present embodiment of the invention may be implemented in a structure which a vacant space area is formed between a first gate insulating film 20a formed to cover the gate electrode 10, and a second gate insulating film 20b formed to cover the first gate insulating film 20a.
  • the space region (the sensing space part) is formed in the inner portion of the gate insulating film so that touch sensing can be implemented by detecting a variation in volume of the sensing space part which is changed depending on pressure applied to the sensing space part.
  • the configuration of the display device including the touch sensor according to the present embodiment of the invention may include: a first substrate 100; a touch sensor; a second substrate 200, a column spacer 210, a black matrix 220, a liquid crystal 230; and a color filter 240.
  • the display device displays an image by adjusting a light transmittance of the liquid crystal using an electric field, and in this case, the liquid crystal 230 is driven by the electric field formed between a pixel electrode 80 and a common electrode which are disposed to be opposite to the first substrate 100 and the second substrate 200.
  • the first substrate 100 and the second substrate 200 may be formed of an insulating transparent substrate.
  • the first substrate 100 is configured to include a driving device, a sensing device and a switching device in an area where a data line and a gate line intersect.
  • the gate electrode 10 of the driving device, the sensing device and the switching device may be formed on the first substrate 100, and the gate insulating film may be formed on the first substrate 100 and the gate electrode 10.
  • the sensing space part 30 may be formed by patterning an inner portion of the gate insulating film.
  • the gate insulating film may be divided into a first gate insulating film 20a, and a second gate insulating film 20b.
  • the first gate insulating film 20a may be formed on the first substrate to cover the gate electrode 10.
  • the second gate insulating film 20b may be formed to cover the first gate insulating film 20a, and a sensing space part 30 may be formed between the first gate insulating film 20a and the second gate insulating film 20b
  • the sensing space part 30 may be implemented in a structure in which a vacant space having a fine thickness is formed between the first gate insulating film 20a and the second gate insulating film 20b.
  • a protection layer 70 is located at an upper surface of the first gate insulating film 20a, and the active layer, the N+ layer, a source electrode and a drain electrode of the driving device, a source electrode 60a, a drain electrode 60b and a pixel electrode 80 of the sensing device and the switching device are formed between the protection layer 70 and the first gate insulating film 20a.
  • the sensing space part 30 may be formed between the gate electrode 10 and the gate insulating film 20b. Accordingly, the touch sensor may sense a touch as a volume of the sensing space part 30 is changed by the pressure applied to the sensing space part. For example, in the touch sensor, the volume of the sensing space part is reduced by the pressure, and a distance between the gate and the active layer is reduced, and thus a capacitance of the thin film transistor increases. As a result, the current value of the thin film transistor is changed, and when the changed current value is greater than a standard current value, the touch may be judged to be sensed.
  • the second substrate 200 may be disposed to be opposite to the first substrate 100, and the column spacer 210 may be disposed between the first substrate 100 and the second substrate 200.
  • one end of the column spacer 210 is disposed on the first substrate 100, and another end of the column spacer 210 is disposed on the second substrate 200 so that a cell gap between the first substrate 100 and the second substrate 200 can be maintained at a regular distance.
  • the column spacer 210 may be disposed at a position corresponding to an upper portion of the sensing space part 30.
  • the black matrix 220 may be disposed between the second substrate 200 and the column spacer 210. In this case, one end of the column spacer 210 may be formed to come into contact with the black matrix 220.
  • the black matrix 220 is intended to shield light, and the color filter 240 having red, green and blue color may be formed on the black matrix 220.
  • the touch sensor according to the present embodiment of the invention may sense a touch as a space of the sensing space part 30 becomes narrow according to the pressure applied by the column spacer 210.
  • the sensing space part 30 may be implemented by: forming a nitride film as the first gate insulating film, and thereafter forming a pattern after depositing an oxide film having a high selectivity; forming a nitride film as a second gate insulating film; and thereafter, etching the oxide film formed in the middle after performing a via hole process, thereby forming the sensing space part as a pattern shape of the oxide film, namely, a vacant space between the first gate insulating film and the second gate insulating film. That is, a patterning process for forming the sensing space part 30 may be implemented using a material having a higher etching selectivity than that of a material which constitutes the first gate insulating film 20a and the second gate insulating film 20b.
  • An active layer such as an amorphous silicon 40 and an n+ amorphous silicon 50 may be formed above the second gate insulating film 20b.
  • the active layer may be formed of any one of an amorphous Si, a polycrystalline Si in which the amorphous silicon is crystallized, a pentacene, thiophene oligomers, a polycrystalline silicon deposited using an LPCVD (Low Pressure Chemical Vapor Deposition) method or a PECVD (Plasma Enhanced Chemical Vapor Deposition) method, and an oxide semiconductor.
  • LPCVD Low Pressure Chemical Vapor Deposition
  • PECVD Pasma Enhanced Chemical Vapor Deposition
  • FIG. 2 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor in a case where a touch is conducted.
  • the space of the sensing space part 30 as shown in FIG 1 is usually maintained at a regular pressure before a touch is performed, and is also maintained in a shape formed by the gate insulating film 20b. However, after the touch is performed, as shown in FIG. 2, the space of the sensing space part is changed.
  • the touch sensor when the second substrate 200 is pressed, the column spacer 210 is moved toward the first substrate 100 due to the pressure, so that the space of the sensing space part 30 becomes narrow.
  • a volume of the sensing space part is reduced by the pressure, and a distance between the gate and the active layer is also reduced, thereby increasing a capacitance of the thin film transistor.
  • the current value of the thin film transistor is changed, and when the changed current value is greater than a standard current value, the touch sensor may judge as sensing the touch.
  • the change of the current value of the thin film transistor due to a difference in the capacitance may be calculated based on a relation of C and I D of the following Math Formula 1.
  • I D represents a drain current of the thin film transistor
  • C represents a capacitance between the gate and the active layer
  • ⁇ n represents a field-effect mobility
  • W represents a width of the thin film transistor
  • L represents a length of the thin film transistor
  • V G represents a gate voltage
  • V TH represens a threshold voltage
  • V D represents a drain voltage.
  • a touch sensor type equipped in a conventional display an electrode is provided at a lower plate by using the conductive material of a column spacer, and a part being in contact with the electrode is conducted, and conducted pixels are sensed.
  • this type is disadvantageous that the unit price of a product increases due to a process cost for production of the column spacer.
  • conductivity of the column spacer is not required. Thus, a process cost can be reduced.
  • the column spacer should accurately come into contact with the electrode formed in the lower plate at a large pressure over a certain level so as to be conducted and sensed.
  • the present embodiment of the invention even in a case where the space of the sensing space part 30 is slightly changed by the column spacer, and thus the current value is changed, a touch may be sensed. Accordingly, through the present embodiment of the invention, the display device equipped with the touch sensor of a high sensitivity may be implemented.
  • FIG. 3 is an equivalent circuit view illustrating the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention.
  • the display device may include: a driving device (a switching TFT) which configured to drive the display device and to which a display scanning line and a data input line are connected; a sensing device (a sensor TFT) which is configured such that a drain terminal is connected to a power electrode, a source terminal is a sensor signal lead out line, and a gate terminal is connected to a sensor scanning line; and a storage capacitor Cst1, one end of which is connected to a drain electrode of the driving device, and another end of which is connected to a common voltage line.
  • a driving device a switching TFT
  • a sensing device a sensor TFT
  • a storage capacitor Cst1 one end of which is connected to a drain electrode of the driving device, and another end of which is connected to a common voltage line.
  • the display device has: a liquid crystal capacity C lc each formed in sub pixel areas defined by a crossing of a gate line and a data line; the driving device connected to a liquid cell each formed in crossing parts; and as torage capacity C st1 parallel-connected to the liquid crystal capacity C lc .
  • the driving device supplies a data signal from the data line to the liquid crystal cell C lc in response to a scan signal from the gate line.
  • the liquid crystal cell C lc is connected to the driving device, and thus a pixel electrode formed at the first substrate overlaps with a common electrode of a second substrate with the liquid crystal as its center so as to be formed in a capacitor shape.
  • one pixel is implemented by a combination of three liquid crystal cells C lc each including the color filter having red color, green color and blue color.
  • the pixels of the touch sensor may be each formed to correspond to the pixels of the display device, or may be formed in a smaller number than that of the pixels of the display device.
  • FIG. 4 is an equivalent circuit view illustrating a display device of a thin film transistor with a touch sensor according to another embodiment of the present invention.
  • the pixel of the touch sensor of FIG. 3 may include a sensor thin film transistor (sensor TFT), a switching thin film transistor (switching TFT2), and a sensor capacitance (C st2 ).
  • the sensor TFT is connected to a sensor gate voltage line having a constant voltage rather than a scanning line so as to be maintained in an "on” state or so as to maintain an operational state of a saturation region where constant currents flow. In the status, electric charges are stored in the sensor capacitance due to the flowing currents.
  • the sensor signal lead out circuit connected through the sensor signal lead out line may sense a difference in the amount of electric charges.
  • FIG. 5 is a schematic diagram illustrating a display device of a thin film transistor with a touch sensor having a pixel circuit depending on an active matrix method.
  • the display device includes: a sensor signal lead out circuit configured to drive a plurality of sensor signal lead out lines 23; a scanning line driving circuit configured to drive a plurality of scanning lines 21; and a data driving circuit configured to drive a plurality of display data input lines 22.
  • Each of a pixel 24 of the display device and a pixel 25 of the touch sensor include a switch transistor (TFT) connected to a plurality of scanning lines, a plurality of sensor signal lead out lines, and a plurality display data input lines to thereby switch each pixel.
  • TFT switch transistor
  • the pixel 25 of the touch sensor may sense a touch by transmitting a current difference value to the sensor signal lead out circuit when a sensor signal is generated by the pressure.
  • the pixel 25 of the touch sensor the amount of electric charges is changed by the pressure, the changed amount of electric charges is stored in the pixel capacitance, a difference value of the amount of electric charges is transmitted to the sensor signal lead out circuit, thereby enabling the touch to be sensed.
  • the pixel 25 of the touch sensor may be equipped in the same number as that of the pixel of the display device, but may be equipped in a smaller number than this of the pixel of the display device at regular intervals.
  • FIG. 6 is flow chart illustrating a method of manufacturing the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention.
  • the method of manufacturing the display device of the thin film transistor with the touch sensor (hereinafter referred to as the manufacturing method) may be performed in the following order.
  • the gate electrode and the first gate insulating film are formed on the first substrate.
  • the first substrate (the lower plate) and the second substrate (the upper plate) may be formed of an insulating transparent substrate.
  • a pattern for formation of the sensing space part is formed on the first gate insulating film.
  • the pattern for formation of the sensing space part is temporarily formed during the process, and is etched and removed in the S40 process among the manufacture processes.
  • the second gate insulating film, the active layer and the N+ layer are deposited and patterned on the pattern for the formation of the sensing space part.
  • the sensing space part is formed by: forming a nitride film as the first gate insulating film, and thereafter, forming a pattern after depositing an oxide film having a high selectivity, forming the nitride film as the second gate insulating film, and thereafter, performing a via hole process and etching the oxide film formed in the middle, thereby forming the sensing space part as a pattern shape of the oxide film, namely, a vacant space between the first gate insulating film and the second gate insulating film.
  • the source electrode and the drain electrode are formed on the N+ layer.
  • the touch sensor equipped in the display device manufactured according to the present embodiment of the invention may sense a touch as the volume of the space (the sensing space part) is changed by the pressure. For example, the touch sensor may judge that the touch is sensed when the current value is changed by the pressure, and the changed current value is greater than the standard current value.
  • the sensing space part may be formed to correspond to the pixels of the display device, or may be formed in a smaller number than that of pixels of the display device.

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Abstract

Provided is a display device of a thin film transistor with a touch sensor, the display device, including: a gate electrode formed on a first substrate; a gate insulating film formed on the first substrate and the gate electrode; and a sensing space part formed in an inner part of the gate insulating film.

Description

DISPLAY DEVICE OF THIN FILM TRANSISTOR WITH TOUCH SENSOR AND METHOD OF MANUFACTURING THE SAME
Embodiments of the present invention relate to a way to perform highly sensitive touch sensing using a thin film transistor.
A liquid crystal display device with a touch screen according to a conventional art is composed of: a color filter substrate including a plurality of color filters; a thin film transistor substrate including a plurality of pixels; and a polarizing plate each attached to the color filter substrate and the outside of the thin film transistor substrate. The liquid crystal display device equipped with the touch screen uses a method of applying a touch signal in such a manner that when a substrate is pressed, a column spacer is pressed by an elastic force of the column spacer to come into contact with a lower plate.
In order to increase touch sensitivity, the liquid crystal display device equipped with the touch screen is configured so that an upper plate, namely, the color filter substrate can be pressed even by a small force by reducing the number of column spacers within a range allowed by the uniformity of cell gaps. In spite of this, in the case of a point touch mode, a touch may be performed by applying a pressure ranging from 80 to 100 gf/cm2, and in the case of a plane touch mode, a touch may be performed by applying a pressure ranging from 350 to 400gf/cm2. Accordingly,even in the case of the plane touch mode, there is a need to improve the touch sensitivity in the same level as that of the point touch mode.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art. An aspect of embodiments of the present invention provides a display device of a thin film transistor with a touch sensor which is capable of forming through a simple manufacturing process because a touch can be sensed using a gate insulating film, which constitutes the thin film transistor, without a need to use a separate device or an additional deposited film.
Another aspect of embodiments of the present invention provides a display device of a thin film transistor with a touch sensor which can easily sense a touch depending on a variation in volume of a space formed between a gate electrode and a second gate insulating film even through pressure applied to a display panel is not large, and a method of manufacturing the same.
Still another aspect of embodiments of the present invention provides a display device of a thin film transistor with a touch sensor which can easily sense a touch using a current value which is changed by pressure applied to a display panel by the touch, and a method of manufacturing the same.
According to an aspect of embodiments of the present invention, there is provided a display device of a thin film transistor with a touch sensor, including: a gate electrode formed on a first substrate; a gate insulating film formed on the first substrate and the gate electrode; and a sensing space part formed by patterning an inner portion of the gate insulating film. The gate insulating film in which the sensing space part is formed may composed of a first gate insulating film formed on the first substrate to cover the gate electrode, and a second gate insulating film formed to cover the first gate insulating film. In this case, the touch sensor may sense a touch as a volume of the sensing space part is changed by pressure applied to the sensing space part.
According to the embodiments of the present invention, since a touch can be sensed using the gate insulating film, which constitutes the thin film transistor, without a need to use a separate element or an additional deposition film, a manufacturing process is simple.
Also, according to the embodiments of the present invention, even though the pressure applied to the display panel is not large, a touch can be easily sensed depending on a variation in volume of a space formed between the gate electrode and a second gate insulating film.
Also, according to the embodiments of the present invention, a touch can be easily sensed using a current value which is changed by pressure applied to the display panel by the touch.
FIG. 1 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor according to one embodiment;
FIG. 2 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor in a case where a touch is conducted;
FIG. 3 is an equivalent circuit view illustrating the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention;
FIG. 4 is an equivalent circuit view illustrating a display device of a thin film transistor with a touch sensor according to another embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a display device of a thin film transistor with a touch sensor having a pixel circuit depending on an active matrix method; and
FIG. 6 is flow chart illustrating a method of manufacturing the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention.
Exemplary embodiments according to the present invention will now be described more fully hereinafter with reference to the accompanying drawings. In the explanation with reference to the accompanying drawings, regardless of reference numerals of the drawings, like numbers refer to like elements through the specification, and repeated explanation thereon is omitted. Terms such as a first term and a second term may be used for explaining various constitutive elements, but the constitutive elements should not be limited to these terms. These terms is used only for the purpose for distinguishing a constitutive element from other constitutive element.
The gist of embodiments of the present invention is to provide a display device having a touch sensor which is configured such that a sensing space part is formed in a gate insulating film itself, which constitutes an thin film transistor, without a need to form a separate element so that a touch can be sensed, thereby improving the efficiency of a manufacturing process, and even though pressure applied to a display panel is not large, the touch can be easily sensed depending on a variation in volume of a space formed between a gate electrode and a second gate insulating film.
FIG. 1 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor according to one embodiment
Referring to FIG. 1, a display device of a thin transistor with a touch sensor according to one embodiment of the present invention (hereinafter referred to as a display device) has the touch sensor including: a gate electrode 10 formed on a first substrate 100; a gate insulating film formed on the first substrate 100 and the gate electrode 10; and a sensing space part 30 formed in an inner portion of the gate insulating film. That is, the display device is characterized by implementing a structure in which a space area (the sensing space part) of a vacant structure is provided in the inner portion of the gate insulating film.
The gate insulating film may have a structure which is implemented as an independent one layer. However, in the present embodiment of the invention, a configuration in which the sensing space part is formed by two insulating film layers will be explained as an example. That is, the sensing space part 30 according to the present embodiment of the invention may be implemented in a structure which a vacant space area is formed between a first gate insulating film 20a formed to cover the gate electrode 10, and a second gate insulating film 20b formed to cover the first gate insulating film 20a.
Accordingly, in the structure of the touch sensor according to the present embodiment of the invention, a separate element or a deposited film is not required, and the space region (the sensing space part) is formed in the inner portion of the gate insulating film so that touch sensing can be implemented by detecting a variation in volume of the sensing space part which is changed depending on pressure applied to the sensing space part.
The configuration of the display device including the touch sensor according to the present embodiment of the invention and having the technical gist as described above will be specifically explained with reference to FIG. 2.
The configuration of the display device including the touch sensor according to the present embodiment of the invention may include: a first substrate 100; a touch sensor; a second substrate 200, a column spacer 210, a black matrix 220, a liquid crystal 230; and a color filter 240.
The display device according to another embodiment of the present invention displays an image by adjusting a light transmittance of the liquid crystal using an electric field, and in this case, the liquid crystal 230 is driven by the electric field formed between a pixel electrode 80 and a common electrode which are disposed to be opposite to the first substrate 100 and the second substrate 200. The first substrate 100 and the second substrate 200 may be formed of an insulating transparent substrate.
The first substrate 100 is configured to include a driving device, a sensing device and a switching device in an area where a data line and a gate line intersect. The gate electrode 10 of the driving device, the sensing device and the switching device may be formed on the first substrate 100, and the gate insulating film may be formed on the first substrate 100 and the gate electrode 10. The sensing space part 30 may be formed by patterning an inner portion of the gate insulating film.
In the present embodiment of the invention, the gate insulating film may be divided into a first gate insulating film 20a, and a second gate insulating film 20b. The first gate insulating film 20a may be formed on the first substrate to cover the gate electrode 10. The second gate insulating film 20b may be formed to cover the first gate insulating film 20a, and a sensing space part 30 may be formed between the first gate insulating film 20a and the second gate insulating film 20b
More specifically, through process procedures of: forming a nitride film as the first gate insulating film; forming a pattern for formation of the sensing space part after depositing an oxide film having a high selectivity; continuously depositing an nitride film as the second gate insulating, an active layer and an n+ silicon layer on the pattern, and thereafter, patterning them; and etching the oxide film after forming a contact hole, the sensing space part 30 may be implemented in a structure in which a vacant space having a fine thickness is formed between the first gate insulating film 20a and the second gate insulating film 20b. Also, a protection layer 70 is located at an upper surface of the first gate insulating film 20a, and the active layer, the N+ layer, a source electrode and a drain electrode of the driving device, a source electrode 60a, a drain electrode 60b and a pixel electrode 80 of the sensing device and the switching device are formed between the protection layer 70 and the first gate insulating film 20a.
The sensing space part 30 may be formed between the gate electrode 10 and the gate insulating film 20b. Accordingly, the touch sensor may sense a touch as a volume of the sensing space part 30 is changed by the pressure applied to the sensing space part. For example, in the touch sensor, the volume of the sensing space part is reduced by the pressure, and a distance between the gate and the active layer is reduced, and thus a capacitance of the thin film transistor increases. As a result, the current value of the thin film transistor is changed, and when the changed current value is greater than a standard current value, the touch may be judged to be sensed.
The second substrate 200 may be disposed to be opposite to the first substrate 100, and the column spacer 210 may be disposed between the first substrate 100 and the second substrate 200.
In this case, one end of the column spacer 210 is disposed on the first substrate 100, and another end of the column spacer 210 is disposed on the second substrate 200 so that a cell gap between the first substrate 100 and the second substrate 200 can be maintained at a regular distance. The column spacer 210 may be disposed at a position corresponding to an upper portion of the sensing space part 30.
Also, the black matrix 220 may be disposed between the second substrate 200 and the column spacer 210. In this case, one end of the column spacer 210 may be formed to come into contact with the black matrix 220. The black matrix 220 is intended to shield light, and the color filter 240 having red, green and blue color may be formed on the black matrix 220.
The touch sensor according to the present embodiment of the invention may sense a touch as a space of the sensing space part 30 becomes narrow according to the pressure applied by the column spacer 210. The sensing space part 30 may be implemented by: forming a nitride film as the first gate insulating film, and thereafter forming a pattern after depositing an oxide film having a high selectivity; forming a nitride film as a second gate insulating film; and thereafter, etching the oxide film formed in the middle after performing a via hole process, thereby forming the sensing space part as a pattern shape of the oxide film, namely, a vacant space between the first gate insulating film and the second gate insulating film. That is, a patterning process for forming the sensing space part 30 may be implemented using a material having a higher etching selectivity than that of a material which constitutes the first gate insulating film 20a and the second gate insulating film 20b.
An active layer such as an amorphous silicon 40 and an n+ amorphous silicon 50 may be formed above the second gate insulating film 20b. The active layer may be formed of any one of an amorphous Si, a polycrystalline Si in which the amorphous silicon is crystallized, a pentacene, thiophene oligomers, a polycrystalline silicon deposited using an LPCVD (Low Pressure Chemical Vapor Deposition) method or a PECVD (Plasma Enhanced Chemical Vapor Deposition) method, and an oxide semiconductor.
FIG. 2 is a cross-sectional view illustrating a display device of a thin film transistor with a touch sensor in a case where a touch is conducted.
Referring to FIG. 2, the space of the sensing space part 30 as shown in FIG 1 is usually maintained at a regular pressure before a touch is performed, and is also maintained in a shape formed by the gate insulating film 20b. However, after the touch is performed, as shown in FIG. 2, the space of the sensing space part is changed.
That is, when the second substrate 200 is pressed, the column spacer 210 is moved toward the first substrate 100 due to the pressure, so that the space of the sensing space part 30 becomes narrow. In the touch sensor, a volume of the sensing space part is reduced by the pressure, and a distance between the gate and the active layer is also reduced, thereby increasing a capacitance of the thin film transistor. As a result, the current value of the thin film transistor is changed, and when the changed current value is greater than a standard current value, the touch sensor may judge as sensing the touch.
The change of the current value of the thin film transistor due to a difference in the capacitance may be calculated based on a relation of C and ID of the following Math Formula 1.
[Math Formula 1]
Figure PCTKR2013007239-appb-I000001
ID represents a drain current of the thin film transistor, C represents a capacitance between the gate and the active layer, μn represents a field-effect mobility, W represents a width of the thin film transistor, L represents a length of the thin film transistor, VG represents a gate voltage, VTH represens a threshold voltage, and VD represents a drain voltage.
As shown in Math Formula 1, when the capacitance of the thin film transistor increases, the current value linearly increases, and when the changed current value is greater than the standard current value, a touch may be judged to be sensed.
In a touch sensor type equipped in a conventional display, an electrode is provided at a lower plate by using the conductive material of a column spacer, and a part being in contact with the electrode is conducted, and conducted pixels are sensed. However, this type is disadvantageous that the unit price of a product increases due to a process cost for production of the column spacer. However, in the present embodiment of the invention, as long as the pressure of the upper plate is transmitted to the lower plate, conductivity of the column spacer is not required. Thus, a process cost can be reduced.
Also, in the touch sensor type equipped in the conventional display, the column spacer should accurately come into contact with the electrode formed in the lower plate at a large pressure over a certain level so as to be conducted and sensed. On the contrary, in the present embodiment of the invention, even in a case where the space of the sensing space part 30 is slightly changed by the column spacer, and thus the current value is changed, a touch may be sensed. Accordingly, through the present embodiment of the invention, the display device equipped with the touch sensor of a high sensitivity may be implemented.
FIG. 3 is an equivalent circuit view illustrating the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention.
Referring to FIG. 3, the display device may include: a driving device (a switching TFT) which configured to drive the display device and to which a display scanning line and a data input line are connected; a sensing device (a sensor TFT) which is configured such that a drain terminal is connected to a power electrode, a source terminal is a sensor signal lead out line, and a gate terminal is connected to a sensor scanning line; and a storage capacitor Cst1, one end of which is connected to a drain electrode of the driving device, and another end of which is connected to a common voltage line. In pixels in which the touch sensor configured as above is equipped, in a case where a touch is generated by pressure, a current value of the sensor TFT increases. When the sensor scanning line applies an on signal to a corresponding pixel based on the increased current value, the sensor signal lead out circuit connected through the sensor signal lead out line may sense the signal.
The display device has: a liquid crystal capacity Clc each formed in sub pixel areas defined by a crossing of a gate line and a data line; the driving device connected to a liquid cell each formed in crossing parts; and as torage capacity Cst1 parallel-connected to the liquid crystal capacity Clc.
The driving device supplies a data signal from the data line to the liquid crystal cell Clc in response to a scan signal from the gate line. The liquid crystal cell Clc is connected to the driving device, and thus a pixel electrode formed at the first substrate overlaps with a common electrode of a second substrate with the liquid crystal as its center so as to be formed in a capacitor shape. Also, one pixel is implemented by a combination of three liquid crystal cells Clc each including the color filter having red color, green color and blue color. The pixels of the touch sensor may be each formed to correspond to the pixels of the display device, or may be formed in a smaller number than that of the pixels of the display device.
FIG. 4 is an equivalent circuit view illustrating a display device of a thin film transistor with a touch sensor according to another embodiment of the present invention.
Referring to FIG. 4, the pixel of the touch sensor of FIG. 3 may include a sensor thin film transistor (sensor TFT), a switching thin film transistor (switching TFT2), and a sensor capacitance (Cst2).At this time, the sensor TFT is connected to a sensor gate voltage line having a constant voltage rather than a scanning line so as to be maintained in an "on" state or so as to maintain an operational state of a saturation region where constant currents flow. In the status, electric charges are stored in the sensor capacitance due to the flowing currents. In the case of the pixels in which a touch is generated, since the currents are increased by the sensor TFT, a greater amount of electric charges is stored in the sensor capacitance, so that the pixels have the greater amount of electric charges compared to the pixels in which the touch is not generated. When the display scan line applies an "on" signal, the sensor signal lead out circuit connected through the sensor signal lead out line may sense a difference in the amount of electric charges.
FIG. 5 is a schematic diagram illustrating a display device of a thin film transistor with a touch sensor having a pixel circuit depending on an active matrix method.
Referring to FIG. 5, the display device includes: a sensor signal lead out circuit configured to drive a plurality of sensor signal lead out lines 23; a scanning line driving circuit configured to drive a plurality of scanning lines 21; and a data driving circuit configured to drive a plurality of display data input lines 22.
Each of a pixel 24 of the display device and a pixel 25 of the touch sensor include a switch transistor (TFT) connected to a plurality of scanning lines, a plurality of sensor signal lead out lines, and a plurality display data input lines to thereby switch each pixel.
The pixel 25 of the touch sensor may sense a touch by transmitting a current difference value to the sensor signal lead out circuit when a sensor signal is generated by the pressure.
Also, in the pixel 25 of the touch sensor, the amount of electric charges is changed by the pressure, the changed amount of electric charges is stored in the pixel capacitance, a difference value of the amount of electric charges is transmitted to the sensor signal lead out circuit, thereby enabling the touch to be sensed. As illustrated in FIG. 5, the pixel 25 of the touch sensor may be equipped in the same number as that of the pixel of the display device, but may be equipped in a smaller number than this of the pixel of the display device at regular intervals.
FIG. 6 is flow chart illustrating a method of manufacturing the display device of the thin film transistor with the touch sensor according to the one embodiment of the present invention.
Referring to FIG. 6, the method of manufacturing the display device of the thin film transistor with the touch sensor (hereinafter referred to as the manufacturing method) may be performed in the following order.
First, in the S10 process, the gate electrode and the first gate insulating film are formed on the first substrate. In this case, the first substrate (the lower plate) and the second substrate (the upper plate) may be formed of an insulating transparent substrate.
Next, in the S20 process, a pattern for formation of the sensing space part is formed on the first gate insulating film. The pattern for formation of the sensing space part is temporarily formed during the process, and is etched and removed in the S40 process among the manufacture processes.
After this, in the S30 process, the second gate insulating film, the active layer and the N+ layer are deposited and patterned on the pattern for the formation of the sensing space part.
Furthermore, in the S40 process, a via hole is formed so that a part of the pattern for the sensing space part can be exposed, and thereafter, the pattern of the sensing space part formed in the S20 process is etched. At this time, in the manufacturing method, the sensing space part is formed by: forming a nitride film as the first gate insulating film, and thereafter, forming a pattern after depositing an oxide film having a high selectivity, forming the nitride film as the second gate insulating film, and thereafter, performing a via hole process and etching the oxide film formed in the middle, thereby forming the sensing space part as a pattern shape of the oxide film, namely, a vacant space between the first gate insulating film and the second gate insulating film.
After this, in the S50 process, the source electrode and the drain electrode are formed on the N+ layer.
The touch sensor equipped in the display device manufactured according to the present embodiment of the invention may sense a touch as the volume of the space (the sensing space part) is changed by the pressure. For example, the touch sensor may judge that the touch is sensed when the current value is changed by the pressure, and the changed current value is greater than the standard current value.
In this case, in the process for forming the sensing space part according to the present embodiment of the invention, the sensing space part may be formed to correspond to the pixels of the display device, or may be formed in a smaller number than that of pixels of the display device.
The preferred embodiments are disclosed in the drawings and the specification. The specific terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting of example embodiments. Thus, in the detailed description of the invention, having described the detailed exemplary embodiments of the invention, it should be apparent that modifications and variations can be made by persons skilled without deviating from the spirit or scope of the invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims and their equivalents.

Claims (15)

  1. A display device of a thin film transistor with a touch sensor, the display device, comprising:
    a gate electrode formed on a first substrate;
    a gate insulating film formed on the first substrate and the gate electrode; and
    a sensing space part formed in an inner part of the gate insulating film.
  2. The display device according to claim 1, wherein the sensing space part is formed between a first gate insulating film formed to cover the gate electrode and a second gate insulating film formed to cover the first gate insulating film.
  3. The display device according to claim 1 or 2, wherein the touch sensor senses a touch as a volume of the sensing space part is changed by pressure applied to the sensing space part.
  4. The display device according to claim 3, wherein the touch sensor judges to sense a touch when a current value is changed by the pressure, and the changed current value is more than a standard current value.
  5. The display device according to claim 1, further comprising: a second substrate disposed to be opposite to the first substrate; and a column spacer disposed between the first substrate and the second substrate.
  6. The display device according to claim 5, wherein the column spacer is disposed at a position corresponding to an upper portion of the sensing space part.
  7. The display device according to claim 6, wherein the touch sensor senses a touch as the volume of the sensing space part is changed by pressure applied to the column spacer.
  8. The display device according to claim 2, further comprising an active layer formed on the second gate insulating film, wherein the active layer is formed of any one of an amorphous Si, a polycrystalline Si in which an amorphous silicon is crystallized, a pentacene, thiophene oligomers, and a polycrystalline silicone and an oxide semiconductor deposited using an LPCVD (Low Pressure Chemical Vapor Deposition) method or a PECVD (Plasma Enhanced Chemical Vapor Deposition) method.
  9. The display device according to claim 1, wherein pixels of the touch sensor are formed to correspond to pixels of the display device, or are formed in a smaller number than that of the pixels of the display device.
  10. The display device according to claim 9, wherein the display device further comprises a sensor signal lead out circuit.
  11. The display device according to claim 10, wherein each of the pixels of the touch sensor senses a touch in such a manner that when a sensor signal is generated by the pressure, a difference value of currents is transmitted to the sensor signal lead out circuit.
  12. The display device according to claim 11, wherein each of the pixels of the touch sensor sense a touch in such a manner that when an amount of electric charges is changed by the pressure, the changed amount of electric charges is stored in a capacitance of the pixels, and a difference value of the amount of electric charges is transmitted to the sensor signal lead out circui
  13. A method of manufacturing a display device of a thin film transistor with a touch sensor, the method, comprising:
    forming a gate electrode and a first gate insulating film on a first substrate;
    forming a second gate insulating film, an active layer, and an N+ layer deposited on the first gate insulating film, and forming a sensing space part between the first gate insulating film and the second gate insulating film; and
    forming a source electrode and a drain electrode on the N+ layer.
  14. The method according to claim 13, wherein the forming of the sensing space part comprises: forming a pattern for formation of the sensing space part on the first gate insulating film; forming the second gate insulating, the active layer and the N+ layer on the pattern for the formation of the sensing space part; forming a via hole so that a part of the pattern for the formation of the sensing space part can be exposed; and thereafter etching the pattern.
  15. The method according to claim 14, wherein the forming of the sensing space part comprises forming the sensing space part to correspond to pixels of the display device or forming the sensing space part in a smaller number than that of the pixels of the display device.
PCT/KR2013/007239 2013-08-12 2013-08-12 Display device of thin film transistor with touch sensor and method of manufacturing the same WO2015023006A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000223715A (en) * 1998-11-25 2000-08-11 Semiconductor Energy Lab Co Ltd Manufacture of thin film transistor and manufacture of active matrix substrate
US20070264736A1 (en) * 2004-11-11 2007-11-15 Au Optronics Corp. Array substrates for use in liquid crystal displays and fabrication methods thereof
US20090017574A1 (en) * 2004-12-08 2009-01-15 Samsung Electronics, Co., Ltd Thin film transistor, method of manufacturing the same, display apparatus having the same and method of manufacturing the display apparatus
KR20090117308A (en) * 2008-05-09 2009-11-12 삼성전자주식회사 Thin film transistor substrate, method of manufacturing the same and liquid crystal display panel having the thin film transistor substrate
US20120038585A1 (en) * 2010-08-10 2012-02-16 Cheol-Se Kim Liquid crystal display device having touch sensor embedded therein, method for driving the same, and method for fabricating the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000223715A (en) * 1998-11-25 2000-08-11 Semiconductor Energy Lab Co Ltd Manufacture of thin film transistor and manufacture of active matrix substrate
US20070264736A1 (en) * 2004-11-11 2007-11-15 Au Optronics Corp. Array substrates for use in liquid crystal displays and fabrication methods thereof
US20090017574A1 (en) * 2004-12-08 2009-01-15 Samsung Electronics, Co., Ltd Thin film transistor, method of manufacturing the same, display apparatus having the same and method of manufacturing the display apparatus
KR20090117308A (en) * 2008-05-09 2009-11-12 삼성전자주식회사 Thin film transistor substrate, method of manufacturing the same and liquid crystal display panel having the thin film transistor substrate
US20120038585A1 (en) * 2010-08-10 2012-02-16 Cheol-Se Kim Liquid crystal display device having touch sensor embedded therein, method for driving the same, and method for fabricating the same

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