KR101756668B1 - Touch display device and method for determining touch - Google Patents

Abstract

The present invention relates to a touch display apparatus and a touch determination method capable of accurately determining whether or not a touch is made regardless of external noise, and more particularly, to a touch display apparatus and a touch determination method, which include an oscillator for sequentially outputting a plurality of input pulse signals having different frequencies; A touch sensing unit sequentially outputting a plurality of touch sensing signals based on the input pulse signals and whether or not the touch signals are externally applied; And a controller for receiving the touch sense signals from the touch sensing unit in order and generating frequency spectrums of the respective touch sense signals based on a comparison result between a center frequency in each frequency spectrum and input pulse signals corresponding to the center frequency, And a touch determination unit for determining whether or not a touch is applied to the touch region where the touch sensing unit is located.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch display device,

The present invention relates to a touch display device, and more particularly, to a touch display device and a touch determination method capable of accurately determining whether or not a touch is caused regardless of external noise.

The conventional touch display device can not accurately determine whether or not the touch is caused by external noise or the like. In other words, even if a touch is actually applied to a specific area, it is not recognized as a touch due to external noise, or when the touch is not applied to the specific area, .

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method and apparatus for detecting a frequency spectrum characteristic of a touch sensing signal, The present invention is directed to a touch display device and a touch determination method.

The present invention also provides a touch display device and a touch determination method capable of accurately determining presence or absence of touch without being affected by external noise by grasping the amplitude characteristic of the touch detection signal and determining whether or not the touch is applied to the touch area It has its purpose.

According to an aspect of the present invention, there is provided a touch display device including: an oscillator for sequentially outputting a plurality of input pulse signals having different frequencies; A touch sensing unit sequentially outputting a plurality of touch sensing signals based on the input pulse signals and whether or not the touch signals are externally applied; And a controller for receiving the touch sense signals from the touch sensing unit in order and generating frequency spectrums of the respective touch sense signals based on a comparison result between a center frequency in each frequency spectrum and input pulse signals corresponding to the center frequency, And a touch determination unit for determining whether or not a touch is applied to the touch region where the touch sensing unit is located.

The oscillator outputs n (n is an odd number) input pulse signals having different frequencies; The touch determination unit compares the frequency of the input pulse signal and the center frequency of the touch sensing signal corresponding to each other, and when the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal as the comparison result is less than or equal to 0, Or a value less than the predetermined threshold value (a value larger than 0), and when the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal is greater than the threshold value Generates a touch signal; the number of the total touch signals generated according to the touch determination result by the n input pulse signals and the n touch sense signals is compared with the total number of touch signals, When the number of the touch signals is larger than the number of the non-touch signals, the touch sensing unit is touched to the touch area where the touch sensing unit is located It is judged that it is added.

The oscillator includes a DC power supply for generating a DC voltage, a resistor, an inductor and a capacitor group connected in series between a first output terminal and a second output terminal of the DC power supply, And a plurality of switches for selecting any one of a plurality of capacitors included in the capacitor group; An input signal output terminal for outputting the input pulse signal is formed between the inductor and the capacitor group; The capacitor group comprising n capacitors of different capacitances connected in parallel with each other; The n capacitors being independently connected to each of the n switches; One terminal of each of the n capacitors is connected to one side of the resistor, and the other terminal of each of the n capacitors is connected to the second output terminal through the corresponding switch; The n switches are sequentially turned on by first to n-th control signals sequentially output.

The touch sensing unit may include a sensor capacitor connected in parallel between the input signal output terminal and the ground terminal.

Wherein the touch determination unit comprises: an amplifier for amplifying a touch sensing signal output through the sensor capacitor; An analog-to-digital converter for converting the touch sensing signal from the amplifier into a digital signal; A spectrum analyzer for generating a frequency spectrum of the touch sensing signal provided from the analog-to-digital converter; A center frequency is obtained from the frequency spectrum from the spectrum analyzer and the frequency of the input pulse signal corresponding to each other is compared with the center frequency of the touch sensing signal and the center frequency of the touch sensing signal is subtracted from the frequency of the input pulse signal If the difference is less than or equal to 0 or greater than 0 and less than or equal to a predetermined threshold value (greater than 0), the comparison result indicates that the center frequency of the touch sensing signal is subtracted from the frequency of the input pulse signal A preliminary touch determination unit for generating a touch signal when the difference value is greater than the threshold value; And comparing the total number of touch signals generated from the preliminary touch determination unit with the total number of touch signals according to a touch determination result by n input pulse signals and n touch detection signals corresponding to each other, If the total number of touch signals is greater than the total number of touch signals, it is determined that the touch area is not applied to the touch area where the touch sensing part is located, And a final touch determination unit for determining that a touch is applied to the touch region where the touch sensing unit is located if the number of touches is greater than the number of touches.

Wherein the touch determination unit further includes a storage unit for storing the respective frequencies of the first to n-th input pulse signals; The preliminary touch determination unit selects the frequency of the input pulse signal from the storage unit according to the first to the n-th control signals, and compares the selected frequency with the corresponding center frequency.

According to another aspect of the present invention, there is provided a touch determination method including: A) outputting a first input pulse signal among first through n-th input pulse signals having different frequencies; A step B for outputting a first touch sensing signal based on the first input pulse signal and whether or not the touch signal is externally applied; And a controller for generating a frequency spectrum of the first touch sensing signal, comparing a center frequency in the frequency spectrum with a frequency of the first input pulse signal, Generating C step; A step D for sequentially performing the steps A to C for each of the second to n-th input pulse signals to generate a non-touch signal or a touch signal for each of the second to n-th input pulse signals; And comparing the number of the untouched signals and the number of the touch signals, and determining whether a touch is applied to the touch region in which the touch sensing unit is located according to the comparison result.

The input pulse signals output from step A are odd; In the step C, a difference between the frequency of the input pulse signal corresponding to each other and the center frequency of the touch sensing signal is compared and the difference obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal is less than or equal to 0 Or less than 0 and is equal to or smaller than a preset threshold value (a value greater than 0), a non-touch signal is preliminarily generated as a result of the touch determination by the input pulse signal and the touch sensing signal corresponding to each other, When the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the pulse signal is greater than the threshold value, a touch signal is preliminarily generated as a result of touch determination based on the input pulse signal and the touch sensing signal, .

In step D, the number of the untouched signals is compared with the number of the touch signals. If the number of the untouched signals is larger than the number of the touch signals, the touch area is touched If the number of the touch signals is greater than the number of the non-touch signals, the touch sensing unit determines that the touch unit is touched to the touch area where the touch sensing unit is located.

In the step A, the first to n-th input pulse signals are sequentially output according to first to n-th control signals sequentially output.

Wherein each frequency of the first to n < th > input pulse signals is stored in a storage unit; In the step C, the frequency of the stored input pulse signal is selected according to the first to the n-th control signals, and the selected frequency is compared with the corresponding center frequency.

Step B-1 for amplifying the touch sensing signal in step B; And a B-2 step of converting the amplified touch sensing signal into a digital signal; And the steps B-1 and B-2 are located between the step B and the step C, respectively.

According to another aspect of the present invention, there is provided a touch display device including: an oscillator for sequentially outputting a plurality of input pulse signals having different frequencies; A touch sensing unit sequentially outputting a plurality of touch sensing signals based on the input pulse signals and whether or not the touch signals are externally applied; And a controller for receiving the touch sensing signals from the touch sensing unit in order and calculating the amplitudes of the touch sensing signals, And a touch judging unit for judging whether or not the touch is judged.

The oscillator outputs n (n is an odd number) input pulse signals having different frequencies; Wherein the touch sensing unit outputs n touch sensing signals corresponding to the n input pulse signals; Wherein the thresholds are configured with n threshold values having different values to correspond to each of the n input pulse signals; The touch determination unit compares the amplitudes of the touch sensing signals corresponding to each other with a threshold value and generates a touch signal when the amplitude of the touch sensing signal is greater than a threshold value as a result of the comparison, Generates a touch signal when it is less than or equal to the threshold value; When the total number of untouched signals generated according to the touch determination result by the n touch detection signals is compared with the total number of touch signals and if the total number of untouched signals is greater than the total number of touch signals It is determined that the touch is not applied to the touch region where the touch sensing unit is located, whereas if the total number of touch signals is greater than the total number of the touch signals, .

The oscillator being controlled according to first to n-th pulse signals having different frequencies, the P-type transistor being connected between the high voltage source and the output terminal; An N-type transistor controlled in accordance with the first to the n-th pulse signals and connected between the low voltage source and the output terminal; And a switch control unit sequentially outputting the first to n-th pulse signals according to first to n-th control signals from the outside to supply the first to the n-th pulse signals to the gate electrodes of the P-type transistor and the N-type transistor, do.

The touch sensing unit may include a sensor capacitor connected in parallel between the output terminal and the ground terminal.

Wherein the touch determination unit comprises: an amplifier for amplifying a touch sensing signal output through the sensor capacitor; An analog-to-digital converter for converting the touch sensing signal from the amplifier into a digital signal; Comparing the amplitude of the touch sensing signal provided from the analog-to-digital converter with a threshold value corresponding to the output pulse, and generating a touch signal when the amplitude of the touch sensing signal is greater than the threshold value as a result of the comparison, A preliminary touch determination unit for generating a touch signal when the amplitude of the touch detection signal is less than or equal to a threshold value; And comparing the total number of untouched signals generated according to the touch determination result by the n touch detection signals with the total number of touch signals and comparing the number of total untouched signals with the total number of touch signals When the number of total touch signals is larger than the total number of the un-touch signals, it is determined that the touch area is not touching the touch area where the touch sensing part is located, And a final touch determination unit that determines that the touch operation is performed.

The touch determination unit may further include a storage unit storing the first through n-th threshold values; The preliminary touch determination unit selects a corresponding threshold value from the storage unit according to the first to the n-th control signals, and compares the selected threshold with the amplitude of the corresponding touch sensing signal.

And generating first through n-th threshold values having different values; B) outputting a first input pulse signal among first through n-th input pulse signals having different frequencies; A step C of outputting a first touch sensing signal based on the first input pulse signal and whether or not the touch signal is inputted from the outside; A step D of calculating an amplitude of the first touch sense signal, comparing the amplitude and the first threshold value, and generating either a non-touch signal or a touch signal based on the comparison result; An E step of sequentially performing the steps B to D for each of the second to n-th input pulses to generate a non-touch signal or a touch signal for each of the second to n-th input pulses; And comparing the number of the untouched signals and the number of the touch signals, and determining whether a touch is applied to the touch region in which the touch sensing unit is located according to the comparison result.

N is an odd number; If the amplitude of the touch sensing signal is greater than the threshold value, the touch sensing signal is generated. If the amplitude of the touch sensing signal is larger than the threshold, Is less than or equal to a threshold value, a touch signal is generated.

In step E, the number of total touch signals generated according to the touch determination result by the n touch sensing signals is compared with the total number of touch signals. If the result of the comparison is that the total touch signals When the number of the total touch signals is greater than the total number of the un-touch signals, it is determined that the touch area is not touching the touch area where the touch sensing unit is located It is determined that the touch is applied.

In the step B, the first to n-th input pulse signals are sequentially output according to first to n-th control signals sequentially output.

Wherein the first through the n-th threshold values are stored in a storage unit; In the step D, the stored threshold value is selected according to the first to n-th control signals, and the amplitude of the touch sensing signal is compared with the selected threshold value.

A C-1 step of amplifying the touch sensing signal in step C; And a C-2 step of converting the amplified touch sensing signal into a digital signal; And the step C-1 and the step C-2 are located between the step C and the step D, respectively.

The touch display device and the touch determination method according to the present invention have the following effects.

First, whether or not the touch is judged based on whether or not the center frequency is hardly influenced by the noise. Thus, even if the noise is involved, it is possible to accurately determine whether or not the touch is present.

Second, whether or not the touch is judged based on whether the amplitude is changed or not is substantially affected by the noise. Thus, even if noise is involved, it is possible to accurately determine whether or not the touch is present.

Third, since a plurality of input pulse signals having different frequencies are used to determine the presence or absence of a touch during one touch determination period, more accurate touch points can be grasped.

1 is a view illustrating a touch display apparatus according to an embodiment of the present invention.
2 is a detailed configuration diagram of the touch analysis / determination unit of FIG.
3 is a detailed configuration diagram of an oscillator and a touch determination unit according to the first embodiment of the present invention.
4 is a timing chart of input pulse signals and control signals.
5 is a view showing a frequency spectrum generated by the preliminary touch determination unit of FIG.
6 is a flowchart illustrating a touch determination method according to the first embodiment of the present invention.
7 is a detailed configuration diagram of an oscillator and a touch determination unit according to a second embodiment of the present invention.
8 is a flowchart illustrating a touch determination method according to a second embodiment of the present invention.

1 is a view illustrating a touch display apparatus according to an embodiment of the present invention.

1, a touch display apparatus according to an embodiment of the present invention includes a display panel TP, a touch analysis / determination unit (TAD), a timing controller TC, a gate driver GD, a data driver DD and a gamma voltage generator GV.

The display panel TP includes n (n is a natural number greater than 1) pixels for displaying an image and m (m is a natural number greater than 1) touch sensing units (TS) for sensing a touch from the outside, . This touch sensing part TS is formed on the display panel TP in k pieces (k is a natural number larger than 1) per one pixel.

The touch sensing unit TS is a capacitive sensor. The touch sensing unit TS senses a touch on the display unit of the display panel TP by a finger or a separate touching unit. The touch sensing unit TS sequentially outputs a plurality of touch sensing signals based on input pulse signals and whether the touch signals are externally applied or not.

The touch analysis / determination unit (TAD) analyzes m pieces of touch detection signals provided from m touch sensing units (TS) every frame to determine whether or not to touch each frame, and when there is a touch, The coordinates are calculated. Then, the calculated coordinates are supplied to the timing controller TC.

The timing controller TC corrects the image data from the outside based on the coordinates of the touch area provided from the touch analysis / determination section TAD, and supplies the corrected image data to the data driver DD. The timing controller TC generates a data control signal and a gate control signal using a horizontal synchronizing signal, a vertical synchronizing signal and a dot clock provided from the outside. This data control signal is a control signal for controlling the operation of the data driver DD, and this data control signal is supplied to the data driver DD. The gate control signal is a signal for controlling the gate driver GD, and the gate control signal is supplied to the gate driver GD.

The data driver DD converts the corrected image data supplied from the timing controller TC into an analog signal using the gamma voltage from the gamma voltage generator GV and outputs the analog image data to the display panel TP As shown in Fig.

The gate driver GD sequentially drives the pixels on a horizontal line basis, thereby driving m pixels every frame period.

Hereinafter, the touch analysis / determination unit (TAD) will be described in more detail.

2 is a detailed configuration diagram of the touch analysis / determination unit (TAD) of FIG.

The touch analysis / determination unit according to the present invention includes an oscillator (OS) and a touch determination unit, as shown in FIG.

The oscillator OS sequentially outputs the first to n-th input pulse signals (n is a natural number of 2 or more) having different frequencies. That is, the oscillator OS sequentially outputs the first to n-th input pulse signals through the input signal output terminal IOT (FIG. 3) and the output line OL connected thereto. These input pulse signals are pulse signals each having a constant period, and these input pulse signals may be composed of an odd number or an even number. A sensor capacitor Cs is connected in parallel between the output line OL of the oscillator OS and the ground terminal. The sensor capacitor Cs is included in the touch sensing unit TS.

The touch determination unit (TD) sequentially receives the touch sensing signals from the touch sensing unit (TS), and generates frequency spectrums of the respective touch sensing signals. Then, based on the comparison result between the center frequency in each frequency spectrum and the input pulse signal corresponding to the center frequency, it is determined whether or not the touch is applied to the touch region where the touch sensing portion TS is located.

Specifically, the touch determination unit (TD) compares the frequencies of the input pulse signals corresponding to each other and the center frequency of the touch sensing signal. That is, the center frequency of the touch sensing signal is subtracted from the frequency of the input pulse signal. If the difference obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal is less than or equal to 0 or greater than 0 and less than or equal to a preset threshold value (greater than 0) Thereby generating a non-touch signal. On the other hand, when the difference value is larger than the threshold value, a touch signal is generated.

In this manner, the touch determination unit (TD) generates n untouched signals and touch signals according to the touch determination result by n input pulse signals and n touch sense signals. That is, the sum of the total untouched signals and the total touch signals is n. Where n can be defined as an odd number.

Then, the touch determination unit (TD) compares the total number of untouched signals with the total number of touch signals. If the total number of untouched signals is greater than the total number of touch signals, it is determined that a touch is not applied to the touch region where the touch sensing unit TS is located. On the other hand, if the total number of touch signals is greater than the total number of untouched signals, it is determined that the touch is applied to the touch region where the touch sensing unit TS is located. In other words, if there are more untouched signals among the untouched signals and touch signals constituting the generated n signals than the touch signal, the touch determination unit (TD) determines that the touch is not applied to the corresponding touch region Finally, if there are more touch signals than the non-touch signal, it is finally determined that the touch is applied to the corresponding touch area.

For this operation, the oscillator (OS) and the touch determination unit (TD) may have the following configuration.

FIG. 3 is a detailed configuration diagram of an oscillator (OS) and a touch determination unit (TD) according to the first embodiment of the present invention, and FIG. 4 is a timing diagram of input pulse signals and control signals.

The oscillator OS according to the first embodiment of the present invention includes a DC power source PW, a resistor R, an inductor L, a capacitor group CG, and a plurality of switches SW1 to SW3.

The DC power source PW is a voltage source for generating a DC voltage, and includes a first output terminal for outputting a positive voltage and a second output terminal for outputting a negative voltage.

The resistor R, the inductor L and the capacitor group CG are connected in series between the first output terminal and the second output terminal.

The capacitor group CG constitutes n capacitors C1 to C3. The n capacitors C1 to C3 have different capacitances and are connected in parallel with each other. In Fig. 3, three capacitors C1 to C3 are shown as one embodiment.

The switches SW1 to SW3 are formed of n, and the switches SW1 to SW3 are connected to the capacitors C1 to C3 on a one-to-one basis. One terminal of each of the capacitors C1 to C3 is connected to one side of the resistor R and the other terminal of each of the capacitors C1 to C3 is connected to the second output terminal through the corresponding switch. In Fig. 3, three switches SW1 to SW3 are shown as one embodiment.

 Each of the switches SW1 to SW3 is independently controlled by n control signals CS1 to CS3. In Fig. 2, three control signals CS1 to CS3 are shown as one embodiment. For example, the operation of the first switch SW1 is controlled by the first control signal CS1, the operation of the second switch SW2 is controlled by the second control signal CS2, And the operation of the third switch SW3 is controlled by the third control signal CS3.

The first to third control signals CS1 to CS3 are sequentially output during one touch determination period Pt, as shown in FIG. That is, during the touch determination period Pt, the first control signal CS1 is output first, then the second control signal CS2 is output, and then the third control signal CS3 is output the latest .

During the period in which the first control signal CS1 is output, only the first control signal CS1 is maintained in the high state and the remaining second and third control signals CS2 and CS3 are held in the low state. Accordingly, during the period in which the first control signal CS1 is output, only the first switch SW1 is turned on. When the first switch SW1 is turned on, only the first capacitor C1 is connected between the input signal output terminal IOT and the second output terminal.

During the period in which the second control signal CS2 is output, only the second control signal CS2 maintains a high state and the remaining first and third control signals CS1 and CS3 are held in a low state. Accordingly, during the period in which the second control signal CS2 is output, only the second switch SW2 is turned on. When the second switch SW2 is turned on, only the second capacitor C2 is connected between the input signal output terminal IOT and the second output terminal.

During the period in which the third control signal CS3 is output, only the third control signal CS3 maintains a high state and the remaining first and second control signals CS1 and CS2 are held in a low state. Accordingly, during the period in which the third control signal CS3 is output, only the third switch SW3 is turned on. When the third switch SW3 is turned on, only the third capacitor C3 is connected between the input signal output terminal IOT and the second output terminal.

The first to third switches SW1 to SW3 select any one of the three capacitors C1 to C3 according to the first to third control signals SC1 to SC3, (IOT) and the second output terminal.

Here, the first capacitor C1 among the first to third capacitors C1 to C3 has the smallest capacitance, the third capacitor C3 has the largest capacitance, and the second capacitor C2 has the smallest capacitance, (C1) and the second capacitor (C2). The oscillator OS then outputs the first input pulse signal IPS1 having the relatively lowest frequency when the first capacitor C1 is selected by the first control signal CS1, And outputs the third input pulse signal IPS3 having the relatively highest frequency when the third capacitor C3 is selected by the third control signal CS3. The second input pulse signal IPS2 having the frequency between the first input pulse signal IPS1 and the third input pulse signal IPS3 when the second capacitor C2 is selected by the second control signal CS2, ).

3, the touch determination unit TD according to the first embodiment of the present invention includes an amplifier AMP, an analog-to-digital converter (ADC), a spectrum analyzer SA, a preliminary touch determination unit PTD And a final touch determination unit (FTD), and may further include a storage unit (MEM).

The amplifier AMP amplifies the touch sensing signal output through the sensor capacitor Cs.

The analog-to-digital converter (ADC) converts the touch-sensitive signal from the amplifier (AMP) into a digital signal.

The spectrum analyzer (SA) generates the frequency spectrum of the touch-sensitive signal provided from the analog-to-digital converter (ADC). To this end, the spectrum analyzer SA generates a frequency spectrum for the touch sensing signal by converting the touch sensing signal using a Fourier transform algorithm.

The preliminary touch determination unit (PTD) finds the center frequency in the frequency spectrum from the spectrum analyzer (SA). This center frequency means a harmonic having the highest peak value (signal intensity) in the frequency spectrum, and means a frequency of a signal having the highest intensity among the harmonics excluding the DC component. Then, the preliminary touch determination unit PTD compares the frequencies of the input pulse signals corresponding to each other and the center frequency of the touch sensing signal. When the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal as a result of the comparison is less than or equal to 0 or greater than 0 and less than or equal to a preset threshold value (greater than 0), a touch signal is generated. On the other hand, if the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal as the comparison result is greater than the threshold value, the touch signal is generated.

The final touch determination unit FTD determines the number of total touch signals generated from the preliminary touch determination unit PTD according to the touch determination result by n input pulse signals and n touch detection signals corresponding to each other, Compare the number of signals. If the number of total touch signals is larger than the total number of touch signals, the touch sensing unit TS determines that the touch area is not touched. On the other hand, if the comparison result shows that the total number of touch signals is greater than the total number of the un-touch signals, it is finally determined that the touch is applied to the touch region where the touch sensing unit TS is located.

The memory MEM may be a volatile or non-volatile memory. Each frequency of the first to n-th input pulse signals is stored in advance in the storage unit MEM. As one example, three input pulse signals (IPS1 to IPS3) are shown in FIG. 4, in which the angular frequency values of the first to third input pulse signals IPS1 to IPS3 are And stored as digital data.

The preliminary touch determination unit PTD reads any one frequency from the storage unit MEM according to the first to third control signals CS1 to CS3. For example, when the first control signal CS1 is supplied to the preliminary touch determination unit PTD in a high state, the preliminary touch determination unit PTD outputs the first control signal CS1 corresponding to the first control signal CS1, And reads the frequency of the input pulse signal IPS1 from the storage unit MEM. The preliminary touch determination unit PTD reads the frequency of the second input pulse signal IPS2 from the storage unit MEM in response to the second control signal CS2 in a high state. The preliminary touch determination unit PTD also reads the frequency of the third input pulse signal IPS3 from the storage unit MEM in response to the third control signal CS3 in a high state. Thus, by providing the same first to third control signals CS1 to CS3 to the oscillator OS and the preliminary touch determination unit PTD, the input pulse signal output from the oscillator OS and the correct frequency corresponding thereto Can be compared to the proper timing.

On the other hand, the preliminary touch determination unit PTD can output the untouched signal and the touch signal under the following conditions according to the circuit configuration. For example, the preliminary touch determination unit (PTD) determines whether the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal is less than or equal to 0, or greater than 0 and less than a predetermined threshold Quot; large value "), the touch signal is generated. On the other hand, when the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal as a result of the comparison is greater than the threshold value, the touch signal is generated.

5 is a view showing a frequency spectrum generated by the preliminary touch determination unit PTD of FIG.

5 (a) shows the frequency spectrum of the touch sensing signal when no touch is applied to the touch area, and FIG. 5 (b) shows the frequency spectrum of the touch sensing signal when the touch is applied It shows the frequency spectrum of touch sensing signal.

Here, assuming that the frequency spectra in Figs. 5A and 5B are generated based on the same input pulse signal having the same frequency, for example, the first input pulse signal IPS1 described above, The operation of the preliminary touch determination unit (PTD) will now be described.

First, suppose that the frequency of the first input pulse signal IPS1 is 60 [Khz]. Then, the frequency spectrum of the first touch sensing signal (digital signal) generated by the first input pulse signal IPS1 may be any one of FIGS. 5A and 5B. At this time, assuming that the center frequency in the frequency spectrum shown in FIG. 5A is 60 [Khz] and the center frequency in the frequency spectrum shown in FIG. 5B is 50 [Khz] Suppose the threshold is 5 [Khz].

If the center frequency of the first touch sensing signal is 60 [Khz] as shown in FIG. 5 (a), the result value calculated by the preliminary touch determination unit PTD is zero. That is, if the center frequency (60Khz) of the first touch sensing signal is subtracted from the frequency (60Khz) of the first input pulse signal (IPS1), the result is zero. Accordingly, the preliminary touch determination unit PTD generates a non-touch signal.

However, if the center frequency of the first touch sensing signal is 50 KHz as shown in FIG. 5 (b), the result value calculated by the preliminary touch determination unit PTD is 1. That is, if the center frequency (50Khz) of the first touch sensing signal is subtracted from the frequency (60Khz) of the first input pulse signal (IPS1), the result is 10, which is larger than the threshold value (5Khz). Accordingly, the preliminary touch determination unit PTD generates a touch signal.

In this manner, the preliminary touch determination unit PTD compares the center frequencies of the second to the n-th touch sensing signals with the second to the n-th frequencies (the frequencies of the second to the n-th input pulse signals) Touch signals and touch signals.

On the other hand, the frequency having the highest peak value located on the leftmost side in FIGS. 5A and 5B is a direct current component generally generated when generating the frequency spectrum for the signal, PTD) performs the preliminary touch determination operation in a state where the DC component is excluded.

Fig. 6 is a flowchart showing a touch determination method according to the first embodiment of the present invention. The sequence shown in Fig. 6 corresponds to the configuration of Fig. 3 described above.

The first input pulse signal IPS1 among the first to n < th > input pulse signals having different frequencies is output first, as shown in step S1. In this case, the first to n-th input pulse signals are sequentially outputted by the first to n-th control signals sequentially outputted. In this step S1, the first input pulse signal IPS1 ) Is output first. Where n is an odd number.

Then, as shown in step S2, a first touch sensing signal is output based on the first input pulse signal IPS1 and whether or not the touch signal is externally applied.

Next, as shown in step S3, the first touch sensing signal is converted into a digital signal.

Thereafter, as shown in step S4, a frequency spectrum of the first touch sensing signal is generated.

Next, as shown in step S5, the center frequency in this frequency spectrum is compared with the frequency of the first input pulse signal IPS1. At this time, each frequency of the first to n-th input pulse signals is stored in the storage unit MEM. In this step S5, the frequency of the first input pulse signal IPS1 is stored according to the first control signal CS1 (MEM). Then compare the read frequency with the corresponding center frequency. And generates either a non-touch signal or a touch signal based on the comparison result.

That is, in step S5, the frequency of the input pulse signal corresponding to each other is compared with the center frequency of the touch sensing signal. When the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal as a result of the comparison is equal to or smaller than 0 or equal to or larger than 0 and equal to or smaller than a preset threshold value (greater than 0) Touch signal as a result of the touch determination by the touch sense signal. On the other hand, when the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal as the comparison result is greater than the threshold value, the input pulse signal and the touch sensing signal, .

Next, as shown in step S6, it is determined that the first input pulse signal IPS1 in step S5 is the last input pulse signal. Since the first input pulse signal IPS1 is not the last input pulse signal, it proceeds to steps S1 through S5 for each of the second through n-th input pulses, A touch signal or a touch signal is generated. When the untouched signal or the touch signal for the nth input pulse signal, which is the last input pulse signal, is generated, the total number of untouched signals and the total number of touch signals are compared as shown in step S7. Thereafter, as shown in step S8, it is determined whether or not a touch to the touch area in which the touch sensing part TS is located is permitted according to the comparison result. That is, if the number of the untouched signals is greater than the number of the touch signals, it is determined that the touch is not applied to the touch region where the touch sensing unit TS is located, as shown in step S9. On the other hand, if the number of touch signals is larger than the number of the non-touch signals as a result of the comparison, it is finally determined that the touch is applied to the touch area where the touch sensing unit TS is located, as shown in step S10.

Meanwhile, the oscillator (OS) and the touch determination unit (TD) in the present invention can operate as follows.

The oscillator OS sequentially outputs a plurality of input pulse signals having different frequencies. The oscillator OS sequentially outputs first to nth input pulse signals (n is a natural number of 2 or more). That is, the oscillator OS sequentially outputs the first to n-th input pulse signals through the input signal output terminal IOT and the output line OL connected thereto. These input pulse signals are pulse signals each having a constant period, and these input pulse signals may be composed of an odd number or an even number.

The touch sensing unit TS has the same configuration as the touch sensing unit TS described above in the first embodiment. The touch sensing unit TS outputs n touch sensing signals corresponding to the n input pulse signals.

The touch determination unit (TD) sequentially receives the touch sensing signals from the touch sensing unit (TS), and calculates the amplitudes of the touch sensing signals. Then, based on the comparison result between each amplitude and the corresponding threshold value, it is determined whether or not a touch to the touch area where the touch sensing part TS is located is applied. These thresholds are composed of n threshold values having different values corresponding to each of the n input pulse signals.

That is, the touch determination unit (TD) compares the amplitudes of the touch sense signals corresponding to each other with the threshold value. If the amplitude of the touch sensing signal is greater than the threshold value, the touch signal is generated. On the other hand, when the amplitude of the touch sensing signal is less than the threshold value, the touch signal is generated. Then, the total number of touch signals generated according to the touch determination result by the n touch sense signals is compared with the total number of touch signals. If the number of the total untouched signals is greater than the total number of touch signals, it is determined that a touch is not applied to the touch region where the touch sensing unit TS is located. On the other hand, if the total number of touch signals is greater than the total number of untouched signals, it is determined that the touch is applied to the touch region where the touch sensing unit TS is located.

For this operation, the oscillator (OS) and the touch determination unit (TD) may have the following configuration.

7 is a detailed configuration diagram of an oscillator (OS) and a touch determination unit (TD) according to the second embodiment of the present invention.

The oscillator OS according to the second embodiment of the present invention includes a P-type transistor PT, an N-type transistor NT, and a switch control unit SC, as shown in FIG.

The P-type transistor PT is controlled according to the first to n-th pulse signals having different frequencies, and is connected between the high voltage source VDD and the output terminal OT. To this end, the gate electrode of the P-type transistor PT is connected to the switch control section SC, the source electrode thereof is connected to the high voltage source VDD, and the drain electrode thereof is connected to the output terminal OT.

The N-type transistor NT is controlled according to the first to n-th pulse signals and is connected between the low voltage source and the output terminal OT. To this end, the gate electrode of the N-type transistor NT is connected to the switch control unit SC, the source electrode thereof is connected to the output terminal OT, and the drain electrode thereof is connected to the low voltage source VSS.

The switch control unit SC sequentially outputs the first to the n-th pulse signals according to the first to the n-th control signals from the outside to supply the gate electrodes of the P-type transistor PT and the N-type transistor NT do.

7, the touch determination unit TD according to the second embodiment of the present invention includes an amplifier AMP, an analog-to-digital converter (ADC), a preliminary touch determination unit (PTD) and a final touch determination unit (FTD), and may further include a storage unit (MEM).

The amplifier AMP amplifies the touch sensing signal output through the sensor capacitor Cs.

The analog-to-digital converter (ADC) converts the touch-sensitive signal from the amplifier (AMP) into a digital signal.

The preliminary touch determination unit (PTD) compares the amplitude of the touch sensing signal provided from the analog-to-digital converter (ADC) with a threshold value corresponding to the output pulse. If the amplitude of the touch sensing signal is greater than the threshold value as a result of the comparison, a non-touch signal is generated. On the other hand, if the amplitude of the touch sensing signal is less than the threshold value as a result of the comparison, the touch signal is generated.

The final touch determiner (FTD) compares the total number of untouched signals generated according to the touch determination result by the n touch detection signals with the total number of touch signals. As a result of the comparison, if the total number of untouched signals is greater than the total number of touch signals, it is determined that the touch is not applied to the touch region where the touch sensing unit TS is located. On the other hand, if the number of total touch signals is greater than the total number of untouched signals, it is determined that the touch is detected in the touch area where the touch sensing unit TS is located.

The memory MEM may be a volatile or non-volatile memory. The first to n-th threshold values are stored in advance in the storage unit MEM. As one example, three input pulse signals (IPS1 to IPS3) are shown in Fig. 4, in which first to third threshold values are stored as digital data.

The preliminary touch determination unit PTD reads one of the threshold values from the storage unit MEM according to the first to third control signals CS3. For example, when the first control signal CS1 is supplied to the preliminary touch determination unit PTD in a high state, the preliminary touch determination unit PTD outputs the first control signal CS1 corresponding to the first control signal CS1, And reads the threshold value from the storage unit MEM. The preliminary touch determination unit PTD reads the second threshold value from the storage unit MEM in response to the second control signal CS2 in a high state. Also, the preliminary touch determination unit PTD reads the third threshold value from the storage unit MEM in response to the third control signal CS3 in a high state. By supplying the same first to third control signals CS3 to the oscillator OS and the preliminary touch determination unit PTD as described above, the input pulse signal output from the oscillator OS and the correct threshold value corresponding to the input pulse signal, ≪ / RTI >

On the other hand, the preliminary touch determination unit PTD can output the untouched signal and the touch signal under the following conditions according to the circuit configuration. For example, the preliminary touch determination unit PTD generates a touch signal when the amplitude of the touch sensing signal is greater than a threshold value as a result of the comparison. On the other hand, if the amplitude of the touch sensing signal is less than the threshold value as a result of the comparison, the touch signal is generated.

Fig. 8 is a flowchart showing a touch determination method according to the second embodiment of the present invention. The sequence shown in Fig. 8 corresponds to the configuration of Fig. 7 described above.

First, first to nth threshold values having different values are generated and stored in the storage unit MEM. Where n is an odd number.

Then, as shown in step S1, the first input pulse signal (IPS1) of the first through n-th input pulse signals having different frequencies is output first. The first to n-th input pulse signals are sequentially outputted by the first to n-th control signals sequentially outputted. In this step S1, the first input pulse signal IPS1 ) Is output first.

Next, as shown in step S2, the first touch sensing signal is output based on the first input pulse signal IPS1 and whether or not the touch signal is inputted from the outside.

Then, as shown in step S3, the first touch sensing signal is converted into a digital signal.

Thereafter, as shown in step S4, the amplitude of the first touch sensing signal is calculated.

Next, as shown in step S5, the calculated amplitude is compared with the first threshold value. At this time, the first to nth threshold values are stored in the storage unit MEM. In step S5, the first threshold value is read from the storage unit MEM according to the first control signal CS1. Then, the read threshold is compared with the corresponding amplitude. And generates either a non-touch signal or a touch signal based on the comparison result.

That is, in step S5, the amplitude of the touch sensing signal corresponding to each other is compared with the threshold value. If the amplitude of the touch sensing signal is greater than the threshold value as a result of the comparison, a non-touch signal is generated. On the other hand, if the amplitude of the touch sensing signal is less than the threshold value as a result of the comparison, the touch signal is generated.

Next, as shown in step S6, it is determined that the first input pulse signal IPS1 in step S5 is the last input pulse signal. Since the first input pulse signal IPS1 is not the last input pulse signal, it proceeds to steps S1 through S5 for each of the second through n-th input pulses, A touch signal or a touch signal is generated. When the untouched signal or the touch signal for the nth input pulse signal, which is the last input pulse signal, is generated, the total number of untouched signals and the total number of touch signals are compared as shown in step S7. Thereafter, as shown in step S8, it is determined whether or not a touch to the touch area in which the touch sensing part TS is located is permitted according to the comparison result. If the number of the non-touch signals is greater than the number of the touch signals, it is determined that the touch area is not touching the touch area where the touch sensing unit TS is located, as shown in step S9. On the other hand, if the number of touch signals is larger than the number of the non-touch signals as a result of the comparison, it is finally determined that the touch is applied to the touch area where the touch sensing unit TS is located, as shown in step S10.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

PW: DC power CG: Capacitor group
C #: 1st capacitor SW #: 1st # switch
IOT: Input signal output terminal R: Resistance
L: Inductor OS: Oscillator
TS: Touch sensing part Cs: Sensor capacitor
OL: Output Line AMP: Amplifier
ADC: Analog-to-Digital Converter SA: Spectrum Analyzer
PTD: preliminary touch determination unit FTD: final touch determination unit
MEM: Storage part TD: Touch judgment part
CS #: # control signal

Claims (24)

An oscillator for sequentially outputting a plurality of input pulse signals having different frequencies;
A touch sensing unit sequentially outputting a plurality of touch sensing signals based on the input pulse signals and whether or not the touch signals are externally applied; And
A touch sensing unit for receiving the touch sensing signals from the touch sensing unit in order to generate a frequency spectrum of each of the touch sensing signals and outputting a difference value between a center frequency in each frequency spectrum and an input pulse signal corresponding to the center frequency, A touch signal or a non-touch signal is generated based on the comparison result, the number of total un-touch signals is compared with the total number of touch signals, and according to the comparison result, a touch And a touch judging unit for judging whether or not the touch input unit is turned on. The method according to claim 1,
The oscillator outputs n (n is an odd number) input pulse signals having different frequencies;
The touch judging unit,
A difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal as a result of the comparison is less than or equal to 0, A touch signal is generated when the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal is greater than the threshold value, ;
the number of the total touch signals generated according to the touch determination result by the n input pulse signals and the n touch sense signals is compared with the total number of touch signals, When the number of the touch signals is larger than the number of the non-touch signals, the touch sensing unit is touched to the touch area where the touch sensing unit is located The touch panel is judged to have been applied. 3. The method of claim 2,
The oscillator includes a DC power supply for generating a DC voltage, a resistor, an inductor and a capacitor group connected in series between a first output terminal and a second output terminal of the DC power supply, And a plurality of switches for selecting any one of a plurality of capacitors included in the capacitor group;
An input signal output terminal for outputting the input pulse signal is formed between the inductor and the capacitor group;
The capacitor group comprising n capacitors of different capacitances connected in parallel with each other;
The n capacitors being independently connected to each of the n switches;
One terminal of each of the n capacitors is connected to one side of the resistor, and the other terminal of each of the n capacitors is connected to the second output terminal through the corresponding switch;
Wherein the n switches are sequentially turned on by the first through n-th control signals sequentially output during one touch determination period (Pt). The method of claim 3,
The touch-
And a sensor capacitor connected in parallel between the input signal output terminal and the ground terminal. 5. The method of claim 4,
The touch judging unit,
An amplifier for amplifying a touch sensing signal output through the sensor capacitor;
An analog-to-digital converter for converting the touch sensing signal from the amplifier into a digital signal;
A spectrum analyzer for generating a frequency spectrum of the touch sensing signal provided from the analog-to-digital converter;
A center frequency is searched in the frequency spectrum from the spectrum analyzer and the frequency of the input pulse signal corresponding to each other is compared with the center frequency of the touch sensing signal and the center frequency of the touch sensing signal is subtracted from the frequency of the input pulse signal If the difference is less than or equal to 0 or greater than 0 and less than or equal to a predetermined threshold value (greater than 0), the comparison result indicates that the center frequency of the touch sensing signal is subtracted from the frequency of the input pulse signal A preliminary touch determination unit for generating a touch signal when the difference value is greater than the threshold value; And
The number of total touch signals generated from the preliminary touch determination unit is compared with the total number of touch signals according to a touch determination result by n input pulse signals and n touch detection signals corresponding to each other, When the number of total touch signals is greater than the total number of touch signals, it is determined that the touch area is not applied to the touch area where the touch sensing part is located, And a final touch determiner for determining that a touch is applied to a touch area where the touch sensing unit is located. 6. The method of claim 5,
Wherein the touch determination unit further includes a storage unit for storing the respective frequencies of the first to n-th input pulse signals; And,
Wherein the preliminary touch determination unit selects a frequency of the input pulse signal from the storage unit according to the first to the n-th control signals, and compares the selected frequency with the corresponding center frequency. An A step of outputting a first input pulse signal among first through n-th input pulse signals having different frequencies;
A step B for outputting a first touch sensing signal based on the first input pulse signal and whether or not the touch signal is externally applied;
And a controller for comparing the difference value between the center frequency in the frequency spectrum and the frequency of the first input pulse signal to a threshold value, A step C of generating any one of the touch signals;
A step D for sequentially performing the steps A to C for each of the second to n-th input pulse signals to generate a non-touch signal or a touch signal for each of the second to n-th input pulse signals; And
Comparing the number of the untouched signals and the number of the touch signals, and determining whether a touch is applied to the touch region where the touch sensing unit is located according to the comparison result. 8. The method of claim 7,
The input pulse signals output from step A are odd; And,
In step C, a difference between the frequency of the input pulse signal and the center frequency of the touch sensing signal is compared, and if the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the input pulse signal is less than or equal to 0, Or a value equal to or greater than 0 and equal to or less than a preset threshold value (a value greater than 0), the touch sensor generates a touch signal as a result of touch determination based on the input pulse signal and the touch detection signal, When the difference value obtained by subtracting the center frequency of the touch sensing signal from the frequency of the touch signal is greater than the threshold value, the touch signal is preliminarily generated as a result of touch determination based on the input pulse signal and the touch sensing signal. Touch judging method. 9. The method of claim 8,
In step D, the number of the untouched signals is compared with the number of the touch signals. If the number of the untouched signals is larger than the number of the touch signals, the touch area is touched When the number of the touch signals is greater than the number of the non-touch signals, the touch sensing unit determines that the touch region is touched to the touch region where the touch sensing unit is located. 8. The method of claim 7,
Wherein the first to n-th input pulse signals are sequentially output according to first to n-th control signals sequentially output during one touch determination period (Pt). 11. The method of claim 10,
Wherein each frequency of the first to n < th > input pulse signals is stored in a storage unit;
Wherein in the step C, the frequency of the stored input pulse signal is selected according to the first to the n-th control signals, and the selected frequency is compared with the corresponding center frequency. 8. The method of claim 7,
Step B-1 for amplifying the touch sensing signal in step B; And
And a B-2 step of converting the amplified touch sensing signal into a digital signal;
Wherein the step B-1 and the step B-2 are located between the step B and the step C, respectively. An oscillator for sequentially outputting a plurality of input pulse signals having different frequencies;
A touch sensing unit sequentially outputting a plurality of touch sensing signals based on the input pulse signals and whether or not the touch signals are externally applied; And
The touch sensing unit receives the touch sensing signals sequentially from the touch sensing unit, calculates the amplitudes of the touch sensing signals, generates a touch signal or a non-touch signal based on the comparison result between the amplitudes and the threshold, And a touch determination unit for comparing the number of the touch signals with the total number of the meter signals and determining whether or not a touch to the touch region in which the touch sensing unit is provided is determined according to the comparison result. 14. The method of claim 13,
The oscillator outputs n (n is an odd number) input pulse signals having different frequencies;
Wherein the touch sensing unit outputs n touch sensing signals corresponding to the n input pulse signals;
Wherein the thresholds are configured with n threshold values having different values to correspond to each of the n input pulse signals;
The touch judging unit,
When the amplitude of the touch sensing signal is greater than the threshold value, the non-touch signal is generated. If the amplitude of the touch sensing signal is equal to or smaller than the threshold value Generating a touch signal;
When the total number of untouched signals generated according to the touch determination result by the n touch detection signals is compared with the total number of touch signals and if the total number of untouched signals is greater than the total number of touch signals It is determined that the touch is not applied to the touch region where the touch sensing unit is located, whereas if the total number of touch signals is greater than the total number of the touch signals, Wherein the touch panel is a touch panel. 15. The method of claim 14,
The oscillator includes:
A P-type transistor which is controlled according to first to n-th pulse signals having different frequencies and is connected between a high voltage source and an output terminal;
An N-type transistor controlled in accordance with the first to the n-th pulse signals and connected between the low voltage source and the output terminal; And
And a switch controller for sequentially outputting the first to n-th pulse signals according to first to n-th control signals from the outside and supplying the first to the n-th pulse signals to the gate electrodes of the P-type transistor and the N-type transistor. Display device. 16. The method of claim 15,
The touch-
And a sensor capacitor connected in parallel between the output terminal and the ground terminal. 17. The method of claim 16,
The touch judging unit,
An amplifier for amplifying a touch sensing signal output through the sensor capacitor;
An analog-to-digital converter for converting the touch sensing signal from the amplifier into a digital signal;
Comparing the amplitude of the touch sensing signal provided from the analog-to-digital converter with a threshold corresponding to the output pulse, and generating a touch signal when the amplitude of the touch sensing signal is greater than the threshold value as a result of the comparison, A preliminary touch determination unit for generating a touch signal when the amplitude of the touch detection signal is equal to or less than a threshold value; And
When the total number of untouched signals generated according to the touch determination result by the n touch detection signals is compared with the total number of touch signals and if the total number of untouched signals is greater than the total number of touch signals It is determined that the touch is not applied to the touch region where the touch sensing unit is located, whereas if the total number of touch signals is greater than the total number of the touch signals, And a final touch determination unit for determining a touch state of the touch panel. 18. The method of claim 17,
The touch determination unit may further include a storage unit storing the first through n-th threshold values;
Wherein the preliminary touch determination unit selects a corresponding threshold value from the storage unit according to the first to the n-th control signals, and compares the selected threshold with the amplitude of the corresponding touch sensing signal. And generating first through n-th threshold values having different values;
B) outputting a first input pulse signal among first through n-th input pulse signals having different frequencies;
A step C of outputting a first touch sensing signal based on the first input pulse signal and whether or not the touch signal is inputted from the outside;
A step D of calculating an amplitude of the first touch sense signal, comparing the amplitude and the first threshold value, and generating either a non-touch signal or a touch signal based on the comparison result;
An E step of sequentially performing the steps B to D for each of the second to n-th input pulses to generate a non-touch signal or a touch signal for each of the second to n-th input pulses; And
Comparing the number of the untouched signals and the number of the touch signals, and determining whether a touch is applied to the touch region where the touch sensing unit is located according to the comparison result. 20. The method of claim 19,
N is an odd number;
In step D, the amplitude of the touch sensing signal corresponding to each other is compared with a threshold value. When the amplitude of the touch sensing signal is greater than the threshold value, the non-touch signal is generated. On the other hand, Is less than or equal to a threshold value, generates a touch signal. 20. The method of claim 19,
In step E, the number of total touch signals generated according to the touch determination result by the n touch sensing signals is compared with the total number of touch signals. If the result of the comparison is that the total touch signals When the number of the total touch signals is greater than the total number of the un-touch signals, it is determined that the touch area is not touching the touch area where the touch sensing unit is located Wherein the touch determination unit determines that the touch is applied. 20. The method of claim 19,
Wherein the step b) sequentially outputs the first through n-th input pulse signals according to first through n-th control signals sequentially output during one touch determination period (Pt). 23. The method of claim 22,
Wherein the first through the n-th threshold values are stored in a storage unit;
Wherein in the step D, the stored threshold value is selected according to the first to the n-th control signals, and the amplitude of the touch sensing signal is compared with the selected threshold value. 20. The method of claim 19,
A C-1 step of amplifying the touch sensing signal in step C; And
And a C-2 step of converting the amplified touch sensing signal into a digital signal;
And the step (C-1) and the step (C-2) are located between the step (C) and the step (D).

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