JP2012073668A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device capable of displaying an image and extracting position information on a place to be touched by input means with high accuracy.SOLUTION: The electronic device includes: a display panel; a sensor module having a plurality of sensor circuits 32 each comprising a capacitor 37; and a control module performing read and write operation with respect to the plurality of sensor circuits to determine whether the plurality of sensor circuits overlap a touch position. The control module applies a precharge voltage Vprc1 having a vibration component to a first electrode E1 of the capacitor 37 of the plurality of sensor circuits 32, applies to a second electrode E2 a reference voltage VSS having a vibration component of the same phase as the above vibration component to perform the write operation, and reads capacitance variation of the capacitor 37 caused by a difference in strength of capacitive coupling generated in the first electrode E1 in response to input operation by input means, to perform the read operation.

Description

  Embodiments described herein relate generally to an electronic apparatus that displays an image and extracts position information of a portion touched by an input unit.

  In general, electronic devices such as a PDA (personal digital assistant) and a tablet PC (personal computer) have a liquid crystal display panel having an optical sensor. The electronic device is configured to be able to input data directly from a display screen using a pen or the like. Furthermore, the electronic device can also measure ambient light with an optical sensor. Thereby, the brightness of the display image can be adjusted to correspond to the illuminance of the ambient light.

JP 2006-209205 A JP 2006-244446 A

By the way, when using an electronic device equipped with an optical sensor that can display an image, depending on the external light environment such as lighting, when it is in true contact (input) or when it is simply floating in the air May be difficult to distinguish. If an error occurs in light detection by the optical sensor, an erroneous input occurs. For this reason, there is a need for a technique for accurately extracting the position information of the place touched by the input means.
The present invention has been made in view of the above points, and an object of the present invention is to provide an electronic apparatus that can display an image and can accurately extract position information of a place touched by an input unit.

An electronic device according to an embodiment is
In an electronic device that displays an image and extracts position information of a place touched by an input means,
A display panel having a display surface for displaying an image;
A sensor module having a plurality of sensor circuits each including a capacitor, provided on the display panel;
A control module that performs a write operation and a read operation on the plurality of sensor circuits and determines whether or not the plurality of sensor circuits overlaps a contact position;
The control module is
A precharge voltage having a vibration component is applied to the first electrodes of the capacitors of the plurality of sensor circuits, and a second electrode located on the opposite side of the display surface with respect to the first electrode is vibrated in phase with the vibration component. The write operation is performed by giving a reference voltage having a component,
The reading operation is performed by reading the capacitance variation of the capacitor due to the strength of capacitive coupling generated in the first electrode in response to the input operation by the input means,
In the sensor circuit that does not overlap the contact position, the increase in the voltage value of the first electrode in the write operation is promoted, the value of the holding voltage of the capacitor is large, and the output voltage of the capacitor is constant regardless of the timing. And
In the sensor circuit overlapping the contact position, an increase in the voltage value of the first electrode in the write operation is suppressed, the value of the holding voltage of the capacitor is small, and the output voltage of the capacitor varies depending on the timing. It is a feature.

An electronic device according to an embodiment is
In an electronic device that displays an image and extracts position information of a place touched by an input means,
A display panel having a display surface for displaying an image;
A transparent electrode formed with a transparent electrode facing each other with a gap on the display surface, and a flexible cover;
A sensor module having a plurality of sensor circuits provided on the display panel, each including a capacitor;
A control module that applies a ground level voltage having a vibration component to the transparent electrode, performs a write operation and a read operation on the plurality of sensor circuits, and determines whether or not the plurality of sensor circuits overlap with a contact position. And comprising
The control module is
A precharge voltage that is a constant voltage is applied to the first electrodes of the capacitors of the plurality of sensor circuits, and a reference voltage that is a constant voltage is applied to the second electrode located on the opposite side of the display surface with respect to the first electrode. To perform the write operation,
Performing the reading operation by reading the capacitance variation of the capacitor caused by the strength of capacitive coupling generated in the first electrode in accordance with the variation of the gap caused by the input operation by the input means;
In the sensor circuit that does not overlap the contact position, the increase in the voltage value of the first electrode in the write operation is promoted, the value of the holding voltage of the capacitor is large, and the output voltage of the capacitor is constant regardless of the timing. And
In the sensor circuit overlapping the contact position, an increase in the voltage value of the first electrode in the write operation is suppressed, the value of the holding voltage of the capacitor is small, and the output voltage of the capacitor varies depending on the timing. It is a feature.

FIG. 1 is a plan view showing the configuration of the electronic apparatus according to the first embodiment. FIG. 2 is a schematic sectional view showing the liquid crystal display panel and the backlight unit shown in FIG. FIG. 3 is a diagram showing an equivalent circuit of a pixel of the liquid crystal display panel and a sensor circuit overlapping the pixel. FIG. 4 is a plan view showing the pixel and the sensor circuit. FIG. 5 is a cross-sectional view showing a part of the sensor circuit, showing a capacitor and an amplifier transistor. FIG. 6 is a schematic cross-sectional view showing the liquid crystal display panel provided with the sensor module, and shows a state where the capacitance of the capacitive coupling is generated in the capacitor of the sensor module by the input operation by the input means. is there. FIG. 7 is a diagram showing an equivalent circuit showing the sensor circuit overlapping the contact position. FIG. 8 is a graph showing changes in voltage values of the nodes n0 and n1 shown in FIG. 7 with respect to time in the sensor circuit not overlapping the contact position. FIG. 9 is a graph showing changes in voltage values of the nodes n0 and n1 shown in FIG. 7 with respect to time in the sensor circuit overlapping the contact position. FIG. 10 is a block diagram showing a circuit formed on the array substrate shown in FIG. FIG. 11 is a diagram showing an equivalent circuit of the sensor circuit during a series of operations from a writing operation to a reading operation performed on the sensor circuit. FIG. 12 is a diagram showing an equivalent circuit of the sensor circuit in the series of operations following FIG. FIG. 13 is a diagram showing an equivalent circuit of the sensor circuit in the series of operations following FIG. FIG. 14 is a diagram showing an equivalent circuit of the sensor circuit in the series of operations following FIG. FIG. 15 is a diagram showing an equivalent circuit of the sensor circuit in the series of operations following FIG. FIG. 16 is a block diagram showing a schematic configuration of the sensor IC shown in FIG. FIG. 17 is a graph showing the change in the gradation value of the difference image with respect to time based on the signal output from the sensor circuit in which the input unit is close and the sensor circuit in which the input unit is not close. FIG. 18 is a graph showing the amount of change in the barycentric coordinates of the difference image based on the signal output from the sensor circuit close to the input means with respect to time. FIG. 19 is a diagram in which a side view and a plan view of a liquid crystal display panel showing a state in which input means are in contact with a plurality of locations at the same time are vertically arranged. FIG. 20 is a schematic cross-sectional view showing the liquid crystal display panel and the light guide plate provided with the sensor module, and the reflected light reflected by the input means is detected by an optical sensor by the input operation by the input means. FIG. FIG. 21 is a schematic cross-sectional view showing the liquid crystal display panel and the light guide plate provided with the sensor module. By the input operation by the input means, the ambient light is detected by using an optical sensor, and the shadow of the input means is detected. FIG. FIG. 22 is a diagram showing a modification of the first electrode of the sensor circuit, and is a plan view showing the pixel and the sensor circuit. FIG. 23 is a schematic diagram illustrating a pixel group PXG including a plurality of pixels PX. FIG. 24 is a diagram illustrating a pixel of the liquid crystal display panel and an equivalent circuit of the sensor circuit overlapping the pixel, and is a diagram illustrating a modified example of the sensor circuit. FIG. 25 is a schematic cross-sectional view showing the liquid crystal display panel and the cover, and shows a state where the transparent electrode of the cover is grounded. FIG. 26 is a schematic cross-sectional view showing the liquid crystal display panel and the cover provided with the sensor module, and shows a state in which the outer surface of the cover is pressed by the input operation by the input means. FIG. 27 is a schematic sectional view showing the liquid crystal display panel and the cover, and shows a state in which a ground level voltage is applied to the transparent electrode of the cover. FIG. 28 shows the position information of the portion touched by the input means by changing the potential of the second electrode at the timing of the write operation and the timing of the read operation in the electronic device according to the second embodiment. It is the schematic explaining the concept in the case of doing. FIG. 29 is a diagram illustrating a schematic configuration of the sensor IC and the liquid crystal display panel in the electronic apparatus according to the third embodiment. The precharge voltage Vprc1 output from the DAC of the sensor IC to the liquid crystal display panel side is illustrated. FIG. 5 is a diagram showing an example of processing in which a plurality of potentials are applied to a plurality of pixels at different timings inside the liquid crystal display panel. FIG. 30 is a diagram illustrating a schematic configuration of the sensor IC and the liquid crystal display panel in the electronic apparatus according to the third embodiment. The precharge voltage Vprc1 output from the DAC of the sensor IC to the liquid crystal display panel side is illustrated. FIG. 5 is a diagram illustrating an example of processing in which a plurality of potentials are applied to a plurality of pixels at different timings inside the sensor IC. FIG. 31 is a graph showing a change of the precharge voltage Vprc1 with respect to time in the electronic device according to the third embodiment. FIG. 32 is a diagram showing a plurality of pixels in a partial region of the liquid crystal display panel in the electronic apparatus according to the third embodiment, and an example in which the level of the precharge voltage Vprc1 applied to the pixels is classified into five. FIG. FIG. 33 is a diagram illustrating an example in which the sensor circuit is operated during a period in which four consecutive horizontal blank periods are combined in the electronic apparatus according to the fourth embodiment. FIG. 34 is a diagram illustrating a specific example in which the time for operating the sensor circuit is ensured in the electronic device according to the fourth embodiment. FIG. 35 is a diagram illustrating an example in which all sensor circuits are operated during one horizontal blank period in the electronic device according to the fourth embodiment. FIG. 36 is a diagram illustrating an example in which the sensor circuit is operated in one vertical blank period when interlaced driving is performed in the electronic device according to the fourth embodiment.

Hereinafter, the electronic apparatus according to the first embodiment will be described in detail with reference to the drawings.
FIG. 1 is a plan view illustrating a configuration of an electronic device. As shown in FIG. 1, an electronic device includes a liquid crystal display panel DP as a display panel for displaying an image, a sensor IC (Integrated Circuit) 4 as a control module, a display IC 5, a drive board 6, a power supply circuit 7, a flexible circuit A substrate 8, an interface (I / F) 9 a for the sensor IC 4, and an interface 9 b for the display IC 5 are provided.

  The display IC 5 is mounted on the liquid crystal display panel DP in a chip on glass (COG) manner. The display IC 5 controls display processing. The liquid crystal display panel DP displays an image based on a video signal (Vsig) transmitted from the CPU on the host side via the interface 9a and the display IC 5.

  The flexible substrate 8 is pressure-bonded to the liquid crystal display panel DP and connected to the drive board 6. The power supply circuit 7 and the sensor IC 4 are mounted on the drive board 6. The power supply circuit 7 supplies power to the sensor IC 4 and the display IC 5. The sensor IC 4 may be COG-mounted.

  Various image processing blocks are included in the sensor IC 4. The sensor IC 4 outputs a control signal for driving the built-in circuit to the liquid crystal display panel DP, and also receives data from the sensor (sensor module) output from the liquid crystal display panel DP and performs predetermined signal processing by the user. The “coordinates” and timing of where on the liquid crystal display panel DP are pressed by the input means are calculated and a “contact flag” is output to the host side via the interface 9a.

FIG. 2 is a schematic sectional view showing the liquid crystal display panel DP and the backlight unit BU shown in FIG.
As shown in FIGS. 1 and 2, the liquid crystal display panel DP includes an array substrate 1, a counter substrate 2, and a liquid crystal layer 3. The array substrate 1 and the counter substrate 2 are each formed in a rectangular shape. The array substrate 1 is formed with a size larger than that of the counter substrate 2. The array substrate 1 and the counter substrate 2 are disposed so that the three sides of each of the array substrate 1 and the counter substrate 2 substantially overlap. On the remaining side of the array substrate 1, the array substrate 1 extends outward from the counter substrate 2.

  The array substrate 1 has a rectangular glass substrate 1s as a transparent insulating substrate. An array pattern 1p is formed on the glass substrate 1s. The counter substrate 2 has a rectangular glass substrate 2s as a transparent insulating substrate. A counter pattern 2p is formed on the glass substrate 2s. In this embodiment, the opposing pattern 2p includes a color filter having colored layers of red (R), green (G), and blue (B). The liquid crystal display panel DP has a rectangular display region R1 that overlaps the array substrate 1 and the counter substrate 2. Note that an input area R2, which will be described later, overlaps the display area R1.

  The array substrate 1 and the counter substrate 2 are arranged to face each other with a predetermined gap held by a plurality of columnar spacers 11. The array substrate 1 and the counter substrate 2 are joined to each other by a rectangular frame-shaped sealing material 12 disposed at the peripheral portions of both substrates, which is the peripheral portion of the display region R1.

  The liquid crystal layer 3 is sandwiched between the array substrate 1 and the counter substrate 2 and is surrounded by a sealing material 12. Although not shown, the liquid crystal injection port formed in a part of the sealing material 12 is sealed with a sealing material.

  A polarizing plate 13 is disposed on the outer surface of the array substrate 1, and a polarizing plate 14 is disposed on the outer surface of the counter substrate 2. The polarizing plate 13 has a display surface S. In this embodiment, the display surface S also functions as an input surface.

  The backlight unit BU is disposed on the opposite side of the array substrate 1 with respect to the counter substrate 2. The backlight unit BU includes a light guide plate BUa disposed to face the polarizing plate 14, and a light source BUb and a reflector plate BUc disposed to face one side edge of the light guide plate. The backlight unit BU emits light toward the polarizing plate 14.

  The liquid crystal display panel DP is controlled to transmit the incident backlight. The liquid crystal display panel DP displays an image in the display region R1 by radiating light to the outer surface side of the polarizing plate 13.

FIG. 3 is a diagram showing an equivalent circuit of the pixel PX of the liquid crystal display panel DP and the sensor circuit 32 overlapping the pixel PX. FIG. 4 is a plan view showing the pixel PX and the sensor circuit 32.
As shown in FIGS. 1 to 4, the liquid crystal display panel DP includes a plurality of pixels PX provided in a matrix along the row direction d1 and the column direction d2 orthogonal to each other. The plurality of pixels PX overlap the display surface S. In this embodiment, the number of pixels is 240 × 320 and the pixel pitch is 153 μm.

  The pixel PX includes a first subpixel SPXa, a second subpixel SPXb, and a third subpixel SPXc for displaying different colors among red, green, and blue. In this embodiment, the first subpixel SPXa overlaps the red colored layer, the second subpixel SPXb overlaps the green colored layer, and the third subpixel SPXc overlaps the blue colored layer.

  The array pattern 1p has a plurality of scanning lines 21, a plurality of signal lines 22, and a plurality of auxiliary capacitance lines 23. The scanning lines 21 extend in the row direction d1 and are arranged at intervals in the column direction d2. The auxiliary capacitance line 23 is arranged with an interval from the scanning line 21. As with the scanning line 21, the auxiliary capacitance line 23 extends in the row direction d1 and is arranged at intervals in the column direction d2.

  The signal lines 22 extend in the column direction d2 and are arranged at intervals in the row direction d1. Here, the signal lines 22 are classified into a signal line 22a connected to the first subpixel SPXa, a signal line 22b connected to the second subpixel SPXb, and a signal line 22c connected to the third subpixel SPXc. be able to.

  During the horizontal scanning period and the vertical scanning period, the video signal Vsig is supplied to the signal lines 22a, 22b, and 22c. As will be described later, during the horizontal blank period, the signal line 22c is supplied with a precharge voltage Vprc1 having a vibration component, and the signal line 22b is supplied with a reference voltage VSS having a vibration component in phase with the vibration component of the precharge voltage Vprc1. The other precharge voltage Vprc2, which is a constant voltage, is applied to the signal line 22a.

  The scanning line 21, the signal line 22, and the auxiliary capacitance line 23 are connected to the first subpixel SPXa, the second subpixel SPXb, and the third subpixel SPXc.

  The first subpixel SPXa, the second subpixel SPXb, and the third subpixel SPXc each have a subpixel circuit 31. The subpixel circuit 31 includes a subpixel switch 33 as a switching element, an auxiliary capacitance element CS, and a liquid crystal capacitance LC.

  The sub-pixel switch 33 is formed of a TFT (thin film transistor), and here is formed of an NMOS type TFT. In the sub-pixel switch 33, the gate electrode is connected to the scanning line 21, the source electrode is connected to the signal line 22, and the drain electrode is connected to the auxiliary capacitance element CS and the liquid crystal capacitance LC. The other electrode of the auxiliary capacitance element CS is formed by the auxiliary capacitance line 23. The video signal transmitted from the CPU on the host side through the signal line 22 is connected to the auxiliary capacitive element CS and the auxiliary capacitive element CS via the subpixel switch 33 when the subpixel switch 33 is turned on by the scanning signal transmitted to the scanning line 21. It is given to the liquid crystal capacitor LC and used for display.

  The sensor circuit 32 is provided in the liquid crystal display panel DP and overlaps the pixel PX. A plurality of sensor circuits 32 provided in the liquid crystal display panel DP form a sensor module. The plurality of sensor circuits 32 (sensor modules) are included in the array pattern 1p. Each sensor circuit 32 is disposed across the first subpixel SPXa, the second subpixel SPXb, and the third subpixel SPXc.

Each sensor circuit 32 includes a capacitor 37 as a sensor capacitance, a precharge control switch 38, an amplifier transistor 35, and an output control switch 34.
FIG. 5 is a cross-sectional view showing a part of the sensor circuit 32, and is a view showing the capacitor 37 and the amplifier transistor 35.

  As shown in FIGS. 3 to 5, the capacitor 37 includes a first electrode E1 formed on the glass substrate 1s and a second electrode E2 positioned on the opposite side of the display surface S with respect to the first electrode E1. Have. The first electrode E1 is made of polysilicon (p-Si) and has a larger area than the second electrode E2. The second electrode E2 is disposed to face the first electrode E1 with the gate insulating film GI interposed therebetween. The second electrode E2 is made of molybdenum tungsten (MoW).

  As shown in FIGS. 3 and 4, the precharge control switch 38 is formed of a TFT, and here is formed of an NMOS type TFT. The precharge control switch 38 is connected between the signal line 22c and the first electrode E1, and switches whether to apply the precharge voltage Vprc1 input via the signal line 22c to the first electrode E1.

  Specifically, in the precharge control switch 38, the gate electrode is connected to the control line CRT, the source electrode is connected to the signal line 22c, and the drain electrode is connected to the first electrode E1. The precharge control switch 38 applies a precharge voltage Vprc1 to the first electrode E1 at a timing when a high (H) level control signal is applied to the gate electrode via the control line CRT.

  As illustrated in FIGS. 3 to 5, the amplifier transistor 35 includes a semiconductor layer SL, a gate electrode GE, a source electrode SE, and a drain electrode DE. The semiconductor layer SL is formed on the glass substrate 1s. The semiconductor layer SL is made of polysilicon. The gate electrode GE is disposed to face the semiconductor layer SL with the gate insulating film GI interposed therebetween. The gate electrode GE is made of molybdenum tungsten.

  The source electrode SE and the drain electrode DE are formed on the interlayer insulating film II and are covered with the passivation film PS. The source electrode SE and the drain electrode DE are connected to the source region and the drain region of the semiconductor layer SC through contact holes formed in the interlayer insulating film II and the gate insulating film GI, respectively. The source electrode SE and the drain electrode DE are made of aluminum.

  In the amplifier transistor 35, the gate electrode GE is connected to the first electrode E1, and the source electrode SE is connected to the signal line 22b together with the second electrode E2. The amplifier transistor 35 is formed of a TFT, and here is formed of an NMOS type TFT. The amplifier transistor 35 is in a conductive state (ON) when the attenuation amount of the holding voltage of the capacitor 37 is small, and is in a non-conduction state (OFF) when the attenuation amount of the holding voltage of the capacitor 37 is large. The amplifier transistor 35 functions as an amplifier (source follower amplifier).

  As shown in FIGS. 3 and 4, the output control switch 34 is formed of a TFT, and here is formed of an NMOS type TFT. The output control switch 34 is connected between the drain electrode DE (FIG. 5) and the signal line 22a, and switches to a conductive state when reading the capacitance variation of the capacitor 37.

Specifically, in the output control switch 34, the gate electrode is connected to the control line OPT, the source electrode is connected to the drain electrode DE (FIG. 5), and the drain electrode is connected to the signal line 22a. Another precharge voltage Vprc2 is applied to the signal line 22a. The output control switch 34 is switched to a conductive state at a timing when a high (H) level control signal is applied to the gate electrode via the control line OPT. At that time, the potential of the signal line 22 a varies according to the capacitance variation of the capacitor 37.
The output control switch 34, the precharge control switch 38, and the sub-pixel switch 33 described above are formed using the same material simultaneously with the amplifier transistor 35.

  Each sensor circuit 32 further includes an optical sensor 36 as a detection element. In this embodiment, the optical sensor 36 is formed of a PIN type photodiode. The optical sensor 36 is connected to the capacitor 37 in parallel. Although not shown, the optical sensor 36 is shielded from light by a light shielding member so that the backlight does not directly enter the optical sensor 36. The optical sensor 36 utilizes the characteristics of the semiconductor leakage current and outputs a current corresponding to the amount of incident light. For this reason, the optical sensor 36 can cause the capacitance variation in the capacitor 37 in accordance with the amount of light incident from the display surface S side.

  The capacitor 37, the precharge control switch 38, the amplifier transistor 35, the output control switch 34, and the optical sensor 36 are arranged so as not to concentrate on a specific subpixel. The width of the sub-pixel is adjusted so that the aperture ratio is uniform among the first sub-pixel SPXa, the second sub-pixel SPXb, and the third sub-pixel SPXc.

  FIG. 6 is a schematic cross-sectional view showing a liquid crystal display panel DP provided with a sensor module (sensor circuit 32). Capacitance coupling to a capacitor 37 of the sensor module (sensor circuit 32) by an input operation by the input means 20 is shown. It is a figure which shows the state which is producing the strength.

FIG. 7 is an equivalent circuit showing the sensor circuit 32 overlapping the contact position (position where the input means 20 contacts the display surface S).
In this embodiment, the input means 20 is a conductor such as a finger. Since the first electrode E1 is located closer to the glass substrate 1s (lower layer), the first electrode E1 is easily capacitively coupled to the input means 20.

  As shown in FIGS. 1 and 3 to 7, the sensor IC 4 performs a write operation and a read operation on the plurality of sensor circuits 32, and determines whether or not the plurality of sensor circuits 32 overlap the contact position. to decide.

  The sensor IC 4 applies a precharge voltage Vprc1 having a vibration component to the first electrode E1 of the capacitor 37 of the plurality of sensor circuits 32, and applies a reference voltage VSS having a vibration component in phase with the vibration component to the second electrode E2. The above write operation is performed by giving. Here, the center value of the precharge voltage Vprc1 is 4V. Moreover, although it is the said vibration component, a frequency is 50 Hz and an amplitude is +/- 0.5V. Furthermore, the reference voltage VSS is a ground (GND) level voltage having a vibration component.

  The sensor IC 4 detects a change in the capacitance of the capacitor 37 caused by the strength of the capacitive coupling generated in the first electrode E1 in response to an input operation by the input unit 20 by detecting a change in the potential of the signal line 22a. be able to. The sensor IC 4 performs the reading operation by detecting the potential fluctuation of the signal line 22a. The closer the input means 20 is to the first electrode E1, the stronger the capacitive coupling.

  In the sensor circuit 32 that does not overlap the contact position, the increase in the voltage value of the first electrode E1 in the write operation is promoted, the value of the holding voltage of the capacitor 37 is large, and the output voltage of the capacitor 37 is constant regardless of the timing. is there.

  FIG. 8 is a graph showing changes in voltage values of the nodes n0 and n1 shown in FIG. 7 with respect to time in the sensor circuit 32 not overlapping the contact position. As shown in FIG. 8, it can be seen that the output voltage of the capacitor 37 is constant regardless of the timing. This is because the capacitive coupling is weak, that is, the coupling capacitance CC is small, and the attenuation amount of the vibration component of the holding voltage of the first electrode E1 is small. For this reason, even if the capacitance variation of the capacitor 37 is read and reproduced as a captured image and arranged in time series, there is no significant difference.

  As shown in FIG. 1 and FIGS. 3 to 7, on the other hand, in the sensor circuit 32 overlapping the contact position, the increase in the voltage value of the first electrode E1 in the write operation is suppressed, and the value of the holding voltage of the capacitor 37 The output voltage of the capacitor 37 varies depending on the timing.

  FIG. 9 is a graph showing changes in voltage values of the nodes n0 and n1 shown in FIG. 7 with respect to time in the sensor circuit 32 overlapping the contact position. As shown in FIG. 9, it can be seen that the output voltage of the capacitor 37 varies depending on the timing. This is because the capacitive coupling is strong, that is, the coupling capacitance CC is large, and the attenuation amount of the vibration component of the holding voltage of the first electrode E1 is large. For this reason, when the capacitance variation of the capacitor 37 is read and reproduced as a captured image, the image is shaded depending on the timing.

  As described above, when determining whether or not the input means 20 is in contact with the display surface S, it can be determined by reading the change in the value of the holding voltage of the capacitor 37. Furthermore, the output voltage of the capacitor 37 is Since it can be read whether it fluctuates with timing (moves up and down with the passage of time), it can be determined more accurately.

  FIG. 10 is a block diagram showing a circuit formed on the array substrate 1. As shown in FIG. 10, the lower X driver (X-dr) 41 is mounted on the array substrate 1 by COG mounting or the like. The X driver 41 is a circuit for writing a video signal (Vsig) output from the display IC 5 to a predetermined signal line (22) on the array substrate 1. The lower side precharge circuit 42 is a circuit for writing a predetermined voltage to predetermined signal lines (22 a, 22 c) on the array substrate 1.

  The Y driver (Y-dr) 43 on the right side opens and closes the gate electrode of the subpixel switch (33) at a predetermined timing to write the video signal (Vsig) written on the signal line (22) to the predetermined subpixel. Circuit. The Y driver 43 includes an OPT circuit (not shown) connected to the control line (OPT). The OPT circuit gives a control signal to the control line (OPT) so as to connect the amplifier transistor (35) of the sensor circuit (32) to the signal line (22a) at a predetermined timing.

  An exposure time variable circuit 44 is provided on the left side. The exposure time variable circuit 44 is connected to a control line (CRT). The exposure time variable circuit 44 supplies a control signal to the gate electrode of the precharge control switch 38 to switch the conduction state of the precharge control switch 38. When the precharge control switch 38 is turned on, the precharge voltage (Vprc1) is applied to the first electrode (E1). The exposure time variable circuit 44 is for the optical sensor 36.

  An A / D conversion circuit 45 and an S / R output circuit 46 are provided on the upper side. The A / D conversion circuit 45 converts the sensor signal (the potential fluctuation of the signal line 22a) output from the pixel sensor circuit (32) into a digital signal. The S / R output circuit 46 performs parallel-serial conversion and amplifies the output of the A / D conversion circuit 45 and outputs it to an external LSI (sensor LSI).

Next, a method for driving the sensor circuit 32 by the sensor IC 4 will be described.
11 to 15 are diagrams showing an equivalent circuit of the sensor circuit 32 during a series of operations from a writing operation to a reading operation performed on the sensor circuit 32. FIG. These series of operations are performed during a horizontal blank period in which no video signal is written.

  As shown in FIG. 11, when the driving method of the sensor circuit 32 by the sensor IC 4 is started, first, the precharge control switch 38 is given a control signal of an on state (H level), and the output control switch 34. Is supplied with a control signal at a level (low (L) level) for turning off. For this reason, the precharge control switch 38 is turned on and the output control switch 34 is turned off.

As a result, the precharge voltage Vprc1 having a vibration component applied to the signal line 22c and having a center value of 4 V is applied to the first electrode E1 through the precharge control switch 38. A reference voltage VSS applied to the signal line 22b and having a vibration component in phase with the vibration component of the precharge voltage Vprc1 is applied to the second electrode E2. The reference voltage VSS is always applied to the signal line 22b during the series of operations.
From the above, the capacitor 37 is precharged.

As shown in FIG. 12, subsequently, the precharge control switch 38 and the output control switch 34 are supplied with a control signal at a level for turning off. Therefore, the precharge control switch 38 is switched off and the output control switch 34 is maintained off.
Thereby, the electrostatic capacitance of the capacitor 37 varies due to the strength of the capacitive coupling generated in the first electrode E1 in accordance with the input operation by the input means (20) for a predetermined time.

  If the capacitive coupling is weak, that is, if the coupling capacitance CC is small, the increase of the voltage value of the first electrode E1 is promoted, the first electrode E1 maintains approximately 4V, and the oscillation of the holding voltage of the first electrode E1. The amount of attenuation of the component is reduced.

  If the capacitance coupling is strong, that is, if the coupling capacitance CC is large, the increase in the voltage value of the first electrode E1 is suppressed, the first electrode E1 approaches 0V, and the oscillation component of the holding voltage of the first electrode E1 is reduced. The amount of attenuation increases.

  As shown in FIG. 13, the precharge voltage Vprc2 of 5 V is then applied to the signal line 22a while the precharge control switch 38 and the output control switch 34 are kept off. Thereby, the signal line 22a is precharged. Thereafter, the signal line 22a enters a high impedance state.

  As shown in FIG. 14, subsequently, after the application of the precharge voltage Vprc2 to the signal line 22a is stopped, the output control switch 34 is supplied with a control signal of a level that is turned on at a predetermined timing. For this reason, the precharge control switch 38 is kept off, and the output control switch 34 is turned on.

  As a result, the amplifier transistor 35 and the signal line 22a become conductive, and the precharge voltage Vprc2 of the signal line 22a passes to the signal line 22b (GND) according to the open / close state of the amplifier transistor 35, and the potential of the signal line 22a changes.

  If the remaining voltage of the capacitor 37 remains at 4V, for example, the amplifier transistor 35 is turned on, and the potential of the signal line 22a changes from 5V to 0V. If the remaining voltage of the capacitor 37 is 0V, for example, the amplifier transistor 35 is turned off, and the potential of the signal line 22a remains at 5V and hardly changes.

  As shown in FIG. 15, the comparator 48 then compares the potential of the signal line 22a with the reference voltage of the reference power supply 47, and outputs a high level signal if the potential of the signal line 22a is greater than the reference voltage. When the potential of the signal line 22a is smaller than the reference voltage, a low level signal is output. The output of the comparator 48 is transmitted to the sensor IC 4.

The sensor IC 4 detects a change in the capacitance of the capacitor 37 caused by the strength of the capacitive coupling generated in the first electrode E1 in response to an input operation by the input unit 20 by detecting a change in the potential of the signal line 22a. be able to. That is, the sensor IC 4 can determine whether or not the sensor circuit 32 (capacitor 37) overlaps the contact position.
As described above, the sensor circuit 32 is driven by the sensor IC 4.

FIG. 16 is a block diagram showing a schematic configuration of the sensor IC 4.
As shown in FIG. 16, the sensor IC 4 includes a level shifter (L / S) 91, a gradation circuit 92, a calibration circuit 93, a DAC (Digital Analog Converter) 94, an inter-frame difference processing circuit 96, and an edge detection circuit 97. A contact probability calculation circuit 98 and a RAM (Random Access Memory) 99 are provided.

  The gradation circuit 92 generates a multi-gradation image based on the binary image transmitted from the comparator (48). In other words, the gradation circuit 92 converts the information indicating the capacitance variation of the capacitor (37) into data for each frame period and generates a detection image.

As a method of generating (converting), for example, for each pixel (PX), a sum of binary data consisting of 0 or 1 is obtained in a square area of 12 pixels × 12 pixels around the pixel (PX). Multi-tone values in between are obtained. Alternatively, a multi-tone value between 0 and 255 may be obtained in a square area of 16 × 16 pixels. The suitability value should be determined in consideration of the arrangement efficiency of the memory area provided inside the sensor IC 4. Alternatively, the captured image data may be output as an analog signal by a circuit on the array substrate 1 and converted into a multi-gradation digital signal by the A / D converter in the gradation circuit 92. It is preferable to determine the aptitude value in consideration of the arrangement efficiency of the memory area provided inside the sensor IC 4.

  The calibration circuit 93 outputs a control signal for adjusting the precharge voltage Vprc1 to an appropriate one based on the signal given from the gradation circuit 92. Upon receiving this control signal, the DAC 94 and level shifter 91 adjust the precharge time.

  In addition, the calibration circuit 93 can output a control signal for adjusting the exposure time of the optical sensor 36 to an appropriate one based on the signal given from the gradation circuit 92. Upon receiving this control signal, the DAC 94 and level shifter 91 adjust the precharge time and exposure time.

  The inter-frame difference processing circuit 96 generates a difference image obtained by taking the difference between the multi-tone image in the current frame and the past multi-tone image stored in the RAM 99. In other words, the inter-frame difference processing circuit 96 calculates the difference between the detected images between consecutive frames and generates a difference image. Then, the inter-frame difference processing circuit 96 can extract the contact position (contact region) of the input means (20) from the gradation values of the successive difference images. Thereby, it can be judged whether a plurality of sensor circuits (32) have overlapped with a contact position.

  FIG. 17 shows the gradation value of the difference image with respect to time based on the signal output from the sensor circuit (32) in which the input means (20) is close and the sensor circuit (32) in which the input means (20) is not close. FIG.

  As shown in FIGS. 16 and 17, the solid-line data has a difference image with a gradation value equal to or higher than a predetermined value, and the gradation value is shaded (vibrated). Can be determined that the corresponding sensor circuit (32) overlaps the contact position.

  In the broken line data, since the gradation value of the difference image is less than a predetermined value, and no gradation (vibration) is generated in the gradation value, the inter-frame difference processing circuit 96 includes the corresponding sensor circuit (32). It can be determined that the contact position does not overlap.

  As shown in FIG. 16, the inter-frame difference processing circuit 96 calculates the centroid from the generated difference image, and indicates that the input position coordinate by the input means (20) is at the centroid as a probability calculation candidate. The signal shown is output.

  FIG. 18 is a graph showing the amount of change in the barycentric coordinates of the difference image based on the signal output from the sensor circuit (32) in which the input means (20) is in close proximity with respect to time. As shown in FIGS. 16 and 18, while the input unit (20) is maintaining the contact state (the state in which the input unit (20) is in close proximity) for a moment, the amount of change in the barycentric coordinates of the difference image. Is equal to or less than a predetermined value, and is approximately 0 here, so that the interframe difference processing circuit 96 can determine that the barycentric coordinate of the difference image is the position input by the input means (20).

  As shown in FIG. 16, the edge detection circuit 97 calculates the strength of the edge (the magnitude of the spatial change in gradation) for the multi-gradation image of each frame, and the edge whose gradation value is equal to or greater than a predetermined threshold value. The center of gravity is calculated and a signal indicating that the input position coordinates by the input means (20) are at the center of gravity is output as a probability calculation candidate.

  It is also effective to hold a multi-tone image at the time of completion of calibration in a memory and perform edge detection on a new multi-tone image subtracted from the latest multi-tone image. This is because it is possible to reduce unevenness in imaging due to variations in sensor characteristics, and to truly cut out only the edge by the input means (20).

  The contact probability calculation circuit 98 calculates a contact probability based on signals output from the gradation circuit 92, the interframe difference processing circuit 96, and the edge detection circuit 97, respectively. When the contact probability calculation circuit 98 is set so as to calculate contact averages from various contact determination results, a system with extremely high contact determination accuracy can be realized.

  FIG. 19 is a diagram in which a side view and a plan view of a liquid crystal display panel showing a state in which input means (finger) 20 are in contact with a plurality of locations at the same time are vertically arranged. As shown in FIG. 19, when the input unit 20 is in contact at two places, the gradation value of the difference image is equal to or greater than a predetermined value, and two data in which gradation (vibration) occurs in the gradation value is generated. Become.

In this case as well, by using a method similar to the above method, it is possible to determine whether or not a plurality of sensor circuits (32) are overlapped with the contact position in both places. It is possible to determine where the position coordinates are. In this example, one position coordinate is (X ₁ , Y ₁ ), and the other position coordinate is (X ₂ , Y ₂ ). Of course, the contact timing can also be detected.

Next, the optical sensor 36 will be described.
When the input means 20 is a non-conductor, in the sensor circuit 32 that overlaps the contact position, the first electrode E1 cannot cause the strength of capacitive coupling. Therefore, as described above, the sensor circuit 32 of the electronic device of this embodiment includes the optical sensor 36, so that the electronic device can be contacted by the input unit 20 even if the input unit 20 is non-conductor. Position information can be extracted.

  Here, when a leak current is generated in the optical sensor 36 according to the amount of light incident on the optical sensor 36 for a predetermined exposure time, the holding voltage of the capacitor 37 changes. The capacitor 37 maintains approximately 4V if the leakage current is small, and approaches 0V if the leakage current is large.

  FIG. 20 is a schematic cross-sectional view showing the liquid crystal display panel DP and the light guide plate BUa provided with the sensor module, and the reflected light L2 reflected by the input means 20 by the input operation by the input means 20 is converted into the optical sensor 36. It is a figure which shows the state currently detected using. FIG. 21 is a schematic cross-sectional view showing the liquid crystal display panel DP and the light guide plate BUa provided with the sensor module. By the input operation by the input means 20, the ambient light L1 is detected by using the optical sensor 36, and the input means 20 It is a figure which shows the state which is detecting the shadow of.

  As shown in FIGS. 20 and 21, the sensor IC (4) can detect the illuminance of the ambient light L1 by using another optical sensor (not shown). The plurality of optical sensors 36 selectively detect the ambient light L1 or the reflected light L2 of the light emitted from the light guide plate BUa according to the illuminance of the ambient light L1.

  The sensor IC (4) detects the shadow of the input means 20 by detecting the ambient light L1 when the illuminance of the ambient light L1 is equal to or higher than the reference value (FIG. 21), and the input means when it is less than the reference value. The target to be detected by the plurality of optical sensors 36 is switched so that the reflected light L2 reflected at 20 is detected (FIG. 20).

  For example, when used indoors, when the illuminance of the reflected light L2 is sufficiently higher than the illuminance of the environmental light L1, and the environmental light L1 does not need to be taken into consideration, the sensor IC (4) is reflected by the input means 20. The reflected light L2 is switched to be detected. On the other hand, when used outdoors, when the illuminance of the ambient light L1 is sufficiently higher than the illuminance of the reflected light L2, and the reflected light L2 does not need to be considered, the sensor IC (4) detects the ambient light L1. It switches so that the shadow of the input means 20 may be detected.

  According to the electronic device according to the first embodiment configured as described above, the electronic device displays an image and extracts position information of a place touched by the input means 20. The electronic device includes a liquid crystal display panel DP, a sensor module, and a sensor IC 4. The sensor IC 4 performs a writing operation and a reading operation on the plurality of sensor circuits 32, and determines whether or not the plurality of sensor circuits 32 overlap the contact position.

  The sensor IC 4 applies a precharge voltage Vprc1 having a vibration component to the first electrode E1 of the capacitor 37 of the plurality of sensor circuits 32, and applies a reference voltage VSS having a vibration component in phase with the vibration component to the second electrode E2. The write operation is performed by giving the data. The sensor IC 4 performs the reading operation by reading the capacitance variation of the capacitor 37 caused by the strength of the capacitive coupling generated in the first electrode E1 according to the input operation by the input means 20.

  In the sensor circuit 32 that does not overlap the contact position, the increase in the voltage value of the first electrode E1 in the writing operation is promoted, the value of the holding voltage of the capacitor 37 is large, and the output voltage of the capacitor 37 is constant regardless of the timing. Become. On the other hand, in the sensor circuit 32 overlapping the contact position, an increase in the voltage value of the first electrode E1 in the write operation is suppressed, the value of the holding voltage of the capacitor 37 is small, and the output voltage of the capacitor 37 varies depending on the timing.

As described above, when determining whether or not the input means 20 is in contact with the display surface S, it can be determined by reading the change in the value of the holding voltage of the capacitor 37. Furthermore, the output voltage of the capacitor 37 is Since it can be read whether it fluctuates with timing (moves up and down with the passage of time), it can be determined more accurately.
From the above, it is possible to obtain an electronic apparatus that can display an image and can accurately extract position information of a place touched by an input unit.

Next, a modification of the electronic device according to the first embodiment will be described.
FIG. 22 is a diagram showing a modification of the first electrode E1 of the sensor circuit 32, and is a plan view showing the pixel PX and the sensor circuit 32. FIG. As shown in FIG. 22, the size of the first electrode E <b> 1 among the two electrodes forming the capacitor 37 may be increased. Here, the first electrode E1 extends in the row direction d1 and overlaps the red sub-pixel SPXa. Thereby, it can be set as the 1st electrode E1 which is easy to carry out capacitive coupling with the input means 20. Further, the first electrode E1 is made of polysilicon and has optical transparency, so that a decrease in the luminance level of the display image is suppressed.

  FIG. 23 is a schematic diagram illustrating a pixel group PXG including a plurality of pixels PX. FIG. 24 is a diagram showing an equivalent circuit of the pixel PX of the liquid crystal display panel (DP) and the sensor circuit 32 overlapping the pixel PX. The sensor circuit 32 has a resistance element 39 instead of the photosensor (36). It is a figure which shows a state. The pixel PX shown in FIG. 24 can be used as a pixel dedicated for capacitive coupling. Note that the pixel PX illustrated in FIG. 24 is referred to as a pixel PX without an optical sensor. On the other hand, the pixel PX shown in FIG. 3 is referred to as a pixel PX with an optical sensor.

  As shown in FIGS. 23 and 24, the pixels PX without the photosensor can be arranged at a certain ratio with respect to the pixels PX with the photosensor. Here, the pixel group PXG includes nine pixels PX, and one of the pixels PX is a pixel PX without an optical sensor. The pixel PX without the photosensor is the pixel PX of (5), and the pixel PX with the photosensor is the pixel PX of (1) to (4) and (6) to (9). The resistance element 39 can be formed by implanting impurities into polysilicon.

  The optical film such as the glass substrate 1s and the polarizing plate 13 shown in FIG. 6 and the like is preferably as thin as possible and has a low dielectric constant, and this causes the first electrode E1 to cause capacitance fluctuations in the input means 20. Can be made easier. When the electronic device is a mobile phone, a protective plate such as a transparent acrylic plate may be provided on the display surface S of the liquid crystal display panel DP. In such a case, a transparent insulating material having a low dielectric constant is used for the protective plate. Is preferred.

  With respect to the vibration component of the precharge voltage Vprc1 and the vibration component of the reference voltage VSS shown in FIG. 7 and the like, the frequency is not limited to 50 Hz and can be variously modified, and the amplitude is ± 0. Not limited to 5V, various modifications are possible. In addition, the waveforms of the two vibration components can be variously modified. For example, a triangular wave or a square wave having the same phase may be used.

  FIG. 25 is a schematic cross-sectional view showing the liquid crystal display panel DP and the cover 50, and shows a state where the transparent electrode 52 of the cover 50 is grounded. FIG. 26 is a schematic cross-sectional view showing the liquid crystal display panel DP provided with the sensor module and the cover 50, and shows a state where the outer surface of the cover 50 is pressed by the input operation by the input means 20.

  As shown in FIGS. 25 and 26, the electronic device further includes a cover 50. The cover 50 includes a PET (polyethylene terephthalate resin) film 51 and a transparent electrode 52 formed by applying ITO (Indium Tin Oxide) on the PET film 51. The transparent electrode 52 is grounded. The cover 50 is opposed to the display surface S with a gap, and has flexibility. The cover 50 is formed using the PET film 51, but is not limited thereto, and may be variously deformed, and may be formed using an insulating film (sheet) having flexibility.

  The cover 50 is supported by a support member 55 so that the transparent electrode 52 is disposed at a sufficient distance from the first electrode E1. The liquid crystal display panel DP is also supported by the support member 56. A plurality of spacers (not shown) are provided between the transparent electrode 52 and the polarizing plate 13, and these spacers maintain a gap between the transparent electrode 52 and the polarizing plate 13.

  By pressing the outer surface of the cover 50 with the input means 20, in the sensor circuit (32) overlapping the contact position, the transparent electrode 52 is brought close to the first electrode (E1) and is generated at the first electrode (E1). Capacitive coupling is strengthened. That is, since the PET film 51 (cover 50) is soft, only the transparent electrode 52 in contact with the input means 20 contacts the display surface S.

  From the above, by providing the cover 50 in the electronic device, even if the input means 20 is a non-conductor such as a nail or a pen, it is possible to cause the strength of capacitive coupling in the first electrode. The device can extract the position information of the place to be contacted by the non-conductor input means 20.

  In addition, since the gap (air gap) between the cover 50 and the display surface S is maintained by light contact, the capacitive coupling generated in the first electrode (E1) does not increase. Then, by using this decrease, it is possible to detect the degree of the pressing pressure (Z axis).

  FIG. 27 is a schematic cross-sectional view showing the liquid crystal display panel DP and the cover 50, and shows a state in which the ground level voltage V 52 is applied to the transparent electrode 52. As shown in FIG. 27, for example, the sensor IC (4) applies a ground level voltage V52 having a vibration component to the transparent electrode 52, and performs a write operation and a read operation on the plurality of sensor circuits (32). Then, it is determined whether or not the plurality of sensor circuits (32) overlap the contact position.

  In the above case, the precharge voltage Vprc1 that is a constant voltage is applied to the first electrode (E1) of the capacitor (37) of the plurality of sensor circuits (32), and the reference voltage VSS that is a constant voltage is applied to the second electrode E2. To perform the write operation. That is, no vibration component is added to the precharge voltage Vprc1 and the reference voltage VSS.

  The capacitance variation of the capacitor (37) due to the strength of the capacitive coupling generated in the first electrode (E1) according to the variation in the gap between the cover 50 and the display surface S due to the input operation by the input means 20 is read. The reading operation is performed. Even in the above case, the output voltage of the capacitor 37 overlapping the contact position varies depending on the timing.

  Next, an electronic apparatus according to the second embodiment will be described in detail. In this embodiment, other configurations are the same as those of the first embodiment described above, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  In FIG. 28, the potential of the second electrode E2 is changed according to the timing of the write operation (timing to precharge the capacitor 37) and the timing of the read operation (timing when a signal is output from the sensor circuit 32). It is the schematic explaining the concept in the case of extracting the positional information on the part contacted in FIG.

  As shown in FIG. 28, the liquid crystal display panel (DP) has 400 rows. The sensor IC (4) includes the first electrode (E1) or the second electrode at the timing of applying the precharge voltage (Vprc1) to the first electrode (E1) and the timing of reading the capacitance variation of the capacitor (37). The potential of the electrode (E2) is changed. Here, the sensor IC (4) changes the potential of the second electrode (E2). Specifically, the sensor IC (4) changes the value of the reference voltage VSS applied to the second electrode (E2) from the L level to the H level or from the H level to the L level. When the 2 horizontal scanning period is 88 μs, the frequency of the vibration component of the reference voltage VSS is 11 kHz.

  If the reference voltage VSS is at L level when the capacitor (37) is precharged, and the reference voltage VSS is set to H level when a signal is output from the sensor circuit (32), capacitive coupling with the input means (20) A potential difference is generated in the capacitor (37) at the time of output between the part that is being operated and another part. The capacitor (37) that is capacitively coupled to the input means (20) has a smaller holding voltage.

  And if the fluctuation | variation of the holding voltage of the capacitor | condenser 37 is read and it reproduces as a captured image, the imaging of a contact area will become a striped pattern. This striped pattern is inverted every time the frame changes (N → N + 1 → N + 2). Here, although white and black are described in FIG. 28, this indicates the color (gradation) of the captured image when it is assumed that the input unit 20 is in contact.

  By keeping the above points, the electronic device can be variously modified. For example, the capacitor (37) may be precharged in a lump in the vertical blank period, and the signal output from the sensor circuit (32) may be performed in each horizontal period. Thereby, power consumption can be reduced.

  In addition, the sensor IC (4) has the potential of the transparent electrode (52) at the timing of applying the precharge voltage (Vprc1) to the first electrode (E1) and the timing of reading the capacitance variation of the capacitor (37). May be changed.

  According to the electronic apparatus according to the second embodiment configured as described above, the electronic apparatus includes the liquid crystal display panel DP, the sensor module, and the sensor IC 4, and further includes the cover 50 as necessary. ing. For this reason, the effect similar to the electronic device of 1st Embodiment mentioned above can be acquired.

  The sensor IC 4 changes the potential of the first electrode E1, the second electrode E2, or the transparent electrode 52 at the timing of applying the precharge voltage Vprc1 to the first electrode E1 and the timing of reading the capacitance variation of the capacitor 37. be able to. Since it can be made difficult to be influenced by noise, the accuracy of contact determination can be improved.

Since the contact area can be imaged in a striped pattern, the position information of the part touched by the input means 20 can be extracted from this pattern, so that the circuit configuration of the sensor IC 4 can be simplified. It can be.
From the above, it is possible to obtain an electronic apparatus that can display an image and can accurately extract position information of a place touched by an input unit.

Next, an electronic apparatus according to the third embodiment will be described in detail. In this embodiment, other configurations are the same as those of the first embodiment described above, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.
In the first embodiment described above, the precharge voltage Vprc1 is a constant voltage at a constant level. However, in this embodiment, the voltage level is periodically different.

  FIG. 29 is a diagram showing a schematic configuration of the sensor IC 4 and the liquid crystal display panel. The precharge voltage Vprc1 output from the DAC 100 of the sensor IC 4 to the liquid crystal display panel DP side is divided into a plurality of values in the liquid crystal display panel DP. It is a figure which shows the example processed so that several electric potential might be applied to the pixel PX at a different timing.

FIG. 30 is a diagram illustrating a schematic configuration of the sensor IC 4 and the liquid crystal display panel. A precharge voltage Vprc1 output from the DAC 100 of the sensor IC 4 to the liquid crystal display panel DP is supplied to a plurality of pixels in the sensor IC 4. It is a figure which shows the example processed so that several electric potential might be applied to PX at a different timing.
FIG. 31 is a graph showing a change in precharge voltage Vprc1 with respect to time.

  As shown in FIGS. 29, 30, and 31, the sensor IC 4 applies a precharge voltage Vprc1 having periodically different voltage levels to the first electrode (E1). The electronic device includes switching means that can switch the timing of applying the precharge voltage Vprc1 (opening the precharge control switch 38) to the first electrodes (E1) of the plurality of sensor circuits (32). .

  Even if the threshold value (Vth) of the transistor (TFT) in the sensor circuit 32 varies due to a manufacturing error, any one of the sensor circuits 32 can detect that the input unit 20 is in contact. For this reason, since it can respond even if it does not use the calibration function using the calibration circuit 93, the labor of the said calibration can be saved.

  FIG. 32 is a diagram illustrating a plurality of pixels PX in a partial region of the liquid crystal display panel DP, and is a diagram illustrating an example in which the level of the precharge voltage Vprc1 applied to the pixels PX is classified into five. As shown in FIG. 32, the pixel PX is classified into five pixels PXA (A), PXB (B), PXC (C), PXD (D), and PXE (E). The value (level) of the precharge voltage Vprc1 applied to each pixel PX (the sensor circuit 32 overlapping each pixel PX) is, for example, 2.0V for the pixel PXA, 2.2V for the pixel PXB, and 2.V for the pixel PXC. 4V, the pixel PXD is 2.6V, and the pixel PXE is 2.8V. As described above, the precharge voltage Vprc1 is changed little by little and applied to each pixel PX.

  When applying the precharge voltage Vprc1 to each pixel PX in a regularly changed manner, it is desirable to change the voltage value row by row, column by column, or checkered. As described above, even when the threshold value of the transistor in the sensor circuit (32) varies by applying the precharge voltage Vprc1 to each pixel PX in a regular manner, any one of the sensor circuits 32 can be used as input means. It is possible to detect that 20 has touched. Note that the number of pixels PX to be classified and the voltage value of the precharge voltage Vprc1 are not limited to the above example, and can be variously modified.

  According to the electronic apparatus according to the third embodiment configured as described above, the electronic apparatus includes the liquid crystal display panel DP, the sensor module, and the sensor IC 4, and further includes the cover 50 as necessary. ing. For this reason, the effect similar to the electronic device of 1st Embodiment mentioned above can be acquired.

  The sensor IC 4 applies a precharge voltage Vprc1 having periodically different voltage levels to the first electrode E1. The switching unit can switch the timing at which the precharge voltage Vprc1 is applied to the first electrodes E1 of the plurality of sensor circuits 32.

Even if the threshold value of the transistor in the sensor circuit 32 varies due to a manufacturing error, any one of the sensor circuits 32 can detect that the input unit 20 is in contact. For this reason, since it can respond even if it does not use the calibration function using the calibration circuit 93, the labor of the said calibration can be saved.
From the above, it is possible to obtain an electronic apparatus that can display an image and can accurately extract position information of a place touched by an input unit.

  Next, an electronic apparatus according to the fourth embodiment will be described in detail. In this embodiment, other configurations are the same as those of the first embodiment described above, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  In the first embodiment described above, the sensor circuit (32) that overlaps a plurality of blank pixels is operated every horizontal blank period. In this embodiment, at least two horizontal blanks that are continuous. The sensor circuit (32) overlapped with a plurality of blank pixels is operated during the period.

FIG. 33 is a diagram illustrating an example in which the sensor circuit 32 is operated during a period in which four consecutive horizontal blank periods are combined. As shown in FIG. 33, the sensor IC 4 detects each sensor circuit (32) overlapped with a plurality of blank pixels (PX) during a period (4H blank) of four consecutive horizontal blank periods. Then, a series of operations from the writing operation to the reading operation is performed, and it is determined whether or not each sensor circuit (32) overlaps the contact position.
During the blank period without video, the signal line (22) can be used exclusively for the sensor circuit (32). By using the signal line (22), writing of the video signal (Vsig) to each sub-pixel and the operation of the sensor circuit (32) can be performed, and an increase in wiring can be suppressed. A decrease in the aperture ratio can be suppressed.

  FIG. 34 is a diagram for explaining a specific example in which the time for operating the sensor circuit (32) is secured. As shown in FIG. 34, in this example, the number of display ICs (5) is increased from one (4 selections) to two (2 selections), and the sensor circuit (32) is operated by thinning out 4 × 4. Time can be secured. Thereby, the manufacturing cost of the sensor IC 4 can be reduced and the performance can be improved.

  The sensor IC 4 performs a series of operations from writing operation to reading operation for each sensor circuit (32) that overlaps a plurality of blank pixels (PX) during a period of at least two consecutive horizontal blank periods. It is sufficient to determine whether or not each sensor circuit (32) overlaps the contact position by performing an operation, whereby the above-described effect can be obtained.

  FIG. 35 is a diagram illustrating an example in which all sensor circuits (32) are operated during one vertical blank period (V blank). As shown in FIG. 35, the sensor IC 4 performs a series of operations from the write operation to the read operation for all the sensor circuits (32) during one vertical blank period, and each sensor circuit (32) is in contact with each other. Determine if it overlaps the position. Thereby, as above-mentioned, the fall of an aperture ratio can be suppressed and the reduction of the manufacturing cost of IC4 for sensors and the improvement of a performance can be aimed at.

  FIG. 36 is a diagram illustrating an example in which the sensor circuit 32 is operated during one vertical blank period (V blank) when interlaced driving is performed. As shown in FIG. 36, the sensor IC 4 includes each sensor circuit (32) that overlaps the blank pixels (PX) during the vertical blank period when the pixels (PX) are interlaced. ), A series of operations from a writing operation to a reading operation is performed to determine whether or not each sensor circuit (32) overlaps the contact position.

  In this example, the driving is ½ interlaced and is divided into a plurality of pixels (PX) in odd rows and a plurality of pixels (PX) in even rows. As described above, in the case of 1/2 interlace driving, the interval of the vertical blank period is halved and the reading speed is doubled compared to the case of non-interlace driving. For this reason, it is suitable when it is desired to determine whether each sensor circuit (32) overlaps the contact position by narrowing the time interval.

  When driving as described above, the present invention is not limited to 1/2 interlace drive, and various modifications are possible. For example, 1/3 interlace drive or 1/4 interlace drive may be performed. It is possible to determine whether each sensor circuit (32) overlaps the contact position.

  According to the electronic device according to the fourth embodiment configured as described above, the electronic device includes the liquid crystal display panel DP, the sensor module, and the sensor IC 4, and further includes the cover 50 as necessary. ing. For this reason, the effect similar to the electronic device of 1st Embodiment mentioned above can be acquired.

  The sensor IC 4 performs a series of operations from a write operation to a read operation on each sensor circuit 32 that overlaps a plurality of blank pixels PX during a period of at least two consecutive horizontal blank periods. It can be determined whether or not each sensor circuit 32 overlaps the contact position. Further, the sensor IC 4 performs a series of operations from the writing operation to the reading operation for all the sensor circuits 32 during the vertical blank period, and determines whether or not each sensor circuit 32 overlaps the contact position. be able to. For this reason, it is possible to suppress a decrease in the aperture ratio, and it is possible to reduce the manufacturing cost and improve the performance of the sensor IC 4.

The sensor IC 4 performs a series of operations from a writing operation to a reading operation on each sensor circuit 32 overlapped with the plurality of blank pixels PX during the vertical blank period when the plurality of pixels PX are interlaced. An operation can be performed to determine whether each sensor circuit 32 overlaps the contact position. For this reason, it is possible to determine whether each sensor circuit 32 overlaps the contact position by narrowing the time interval.
From the above, it is possible to obtain an electronic apparatus that can display an image and can accurately extract position information of a place touched by an input unit.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

For example, the display panel is not limited to the liquid crystal display panel DP, and may be any display panel configured to display an image in the display region R1.
The present invention is not limited to the electronic device described above, and can be applied to various electronic devices.

  DESCRIPTION OF SYMBOLS 1 ... Array substrate, 1s ... Glass substrate, 1p ... Array pattern, 2 ... Opposite substrate, 3 ... Liquid crystal layer, 4 ... Sensor IC, 5 ... Display IC, 13 ... Polarizing plate, 20 ... Input means, 22, 22a , 22b, 22c ... signal line, 31 ... sub-pixel circuit, 32 ... sensor circuit, 34 ... output control switch, 35 ... amplifier transistor, 36 ... optical sensor, 37 ... capacitor, 38 ... precharge control switch, 39 ... resistance element 50 ... Cover, 51 ... PET film, 52 ... Transparent electrode, 91 ... Level shifter, 92 ... Gradation circuit, 93 ... Calibration circuit, 94 ... DAC, 96 ... Inter-frame difference processing circuit, 97 ... Edge detection circuit, 98 ... Contact probability calculation circuit, 99 ... RAM, 100 ... DAC, DP ... Liquid crystal display panel, BU ... Backlight unit, E1 ... First electrode, E2 ... First Electrode, CC ... coupling capacitance, Vprc1, Vprc2 ... precharge voltage, VSS ... reference voltage, V52 ... voltage, R1 ... display region, R2 ... input region, S ... display surface, PXG ... pixel group, PX ... pixel, SPXa, SPXb, SPXc ... sub-pixel, d1 ... row direction, d2 ... column direction, L1 ... environment light, L2 ... reflected light.

Claims (14)

In an electronic device that displays an image and extracts position information of a place touched by an input means,
A display panel having a display surface for displaying an image;
A sensor module having a plurality of sensor circuits each including a capacitor, provided on the display panel;
A control module that performs a write operation and a read operation on the plurality of sensor circuits and determines whether or not the plurality of sensor circuits overlaps a contact position;
The control module is
A precharge voltage having a vibration component is applied to the first electrodes of the capacitors of the plurality of sensor circuits, and a second electrode located on the opposite side of the display surface with respect to the first electrode is vibrated in phase with the vibration component. The write operation is performed by giving a reference voltage having a component,
The reading operation is performed by reading the capacitance variation of the capacitor due to the strength of capacitive coupling generated in the first electrode in response to the input operation by the input means,
In the sensor circuit that does not overlap the contact position, the increase in the voltage value of the first electrode in the write operation is promoted, the value of the holding voltage of the capacitor is large, and the output voltage of the capacitor is constant regardless of the timing. And
In the sensor circuit overlapping the contact position, an increase in the voltage value of the first electrode in the write operation is suppressed, the value of the holding voltage of the capacitor is small, and the output voltage of the capacitor varies depending on the timing. Features electronic equipment. A transparent cover that is disposed to face the display surface with a gap and is grounded, and further includes a flexible cover;
By pressing the outer surface of the cover with the input means, in the sensor circuit overlapping the contact position, the transparent electrode is close to the first electrode, and the capacitive coupling generated in the first electrode is strong. The electronic device according to claim 1, wherein In an electronic device that displays an image and extracts position information of a place touched by an input means,
A display panel having a display surface for displaying an image;
A transparent electrode having a transparent electrode disposed opposite to the display surface with a gap, and having a flexibility;
A sensor module having a plurality of sensor circuits provided on the display panel, each including a capacitor;
A control module that applies a ground level voltage having a vibration component to the transparent electrode, performs a write operation and a read operation on the plurality of sensor circuits, and determines whether or not the plurality of sensor circuits overlap with a contact position. And comprising
The control module is
A precharge voltage that is a constant voltage is applied to the first electrodes of the capacitors of the plurality of sensor circuits, and a reference voltage that is a constant voltage is applied to the second electrode located on the opposite side of the display surface with respect to the first electrode. To perform the write operation,
Performing the reading operation by reading the capacitance variation of the capacitor caused by the strength of capacitive coupling generated in the first electrode in accordance with the variation of the gap caused by the input operation by the input means;
In the sensor circuit that does not overlap the contact position, the increase in the voltage value of the first electrode in the write operation is promoted, the value of the holding voltage of the capacitor is large, and the output voltage of the capacitor is constant regardless of the timing. And
In the sensor circuit overlapping the contact position, an increase in the voltage value of the first electrode in the write operation is suppressed, the value of the holding voltage of the capacitor is small, and the output voltage of the capacitor varies depending on the timing. Features electronic equipment. The display panel includes a first subpixel, a second subpixel, and a third subpixel that are stacked on the display surface and display different colors of the red, green, and blue, respectively, and are orthogonal to each other. A plurality of pixels provided in a matrix along the direction and the column direction, and connected to the first subpixel, the second subpixel, and the third subpixel of the plurality of pixels, respectively, and extends along the column direction A plurality of signal lines, and
Each sensor circuit
A precharge control switch connected between the signal line connected to the third subpixel and the first electrode, and for switching whether to apply the precharge voltage input via the signal line to the first electrode;
A gate electrode connected to the first electrode; a source electrode connected to the signal line connected to the second subpixel to which the reference voltage is applied together with the second electrode; and a drain electrode; An amplifier transistor that functions as an amplifier that is conductive when the amount of attenuation of the holding voltage is small and is non-conductive when the amount of attenuation of the holding voltage of the capacitor is large;
An output control switch connected between the drain electrode and the signal line connected to the first subpixel, and switching to a conductive state when reading a capacitance variation of the capacitor;
The signal line connected to the first subpixel is supplied with another precharge voltage,
The potential of the signal line connected to the first sub-pixel varies according to the capacitance variation of the capacitor when the output control switch is switched to a conductive state. The electronic device according to any one of the above.   The control module generates information indicating the capacitance variation of the capacitor for each frame period to generate a detection image, calculates a difference between the detection images between successive frames, generates a difference image, and The electronic apparatus according to claim 1, wherein it is determined whether or not a plurality of sensor circuits overlap the contact position.   The electronic device according to claim 5, wherein the control module determines that a barycentric coordinate of the difference image is a position input by the input unit.   4. The electronic apparatus according to claim 1, wherein the first electrode is made of polysilicon and has a larger area than the second electrode. 5.   Each of the plurality of sensor circuits further includes a detection element connected in parallel to the capacitor, and causing a capacitance variation in the capacitor in accordance with an amount of light incident from the display surface side. The electronic device according to claim 1, wherein the electronic device is a device.   The control module changes the potential of the first electrode or the second electrode at a timing of applying the precharge voltage to the first electrode and a timing of reading a capacitance variation of the capacitor. The electronic device according to any one of claims 1 to 3.   The said control module changes the electric potential of the said transparent electrode with the timing which gives the said precharge voltage to a said 1st electrode, and the timing which reads the electrostatic capacitance fluctuation | variation of the said capacitor | condenser. The electronic device as described in. Further comprising switching means,
The control module provides the first electrode with the precharge voltage having periodically different voltage levels,
4. The electronic device according to claim 1, wherein the switching unit switches a timing at which the precharge voltage is applied to the first electrodes of the plurality of sensor circuits. 5. The display panel includes a first subpixel, a second subpixel, and a third subpixel that are stacked on the display surface and display different colors of the red, green, and blue, respectively, and are orthogonal to each other. A plurality of pixels provided in a matrix along the direction and the column direction;
The control module performs a write operation and a read operation on each sensor circuit overlapping a plurality of blank pixels during a period of at least two consecutive horizontal blank periods, and each sensor circuit is in a contact position. 4. The electronic device according to claim 1, wherein it is determined whether or not the electronic device overlaps with the electronic device.   The control module performs a write operation and a read operation on all sensor circuits during a vertical blank period to determine whether or not each sensor circuit overlaps a contact position. The electronic device as described in. The display panel includes a first subpixel, a second subpixel, and a third subpixel that are stacked on the display surface and display different colors of the red, green, and blue, respectively, and are orthogonal to each other. A plurality of pixels provided in a matrix along the direction and the column direction;
The control module performs a write operation and a read operation on each sensor circuit that overlaps the plurality of blank pixels during the vertical blank period when the plurality of pixels are interlaced. 4. The electronic apparatus according to claim 1, wherein it is determined whether or not the circuit overlaps the contact position.

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