Patent Application
20220147191
This application claims the benefit of priority from Japanese Patent Application No. 2020-188781 filed on Nov. 12, 2020, the entire contents of which are incorporated herein by reference.
The present disclosure relates to an input detection system and an input support device.
Japanese Patent No. 6342105 and Japanese Patent No. 6532631 describe an input support device (described as an operation knob or a knob in Japanese Patent Nos. 6342105 and 6532631) that is placed on a touch panel configured to detect change in electrostatic capacitance or change in a contact region and supports input operations through the touch panel. One known method of detecting an input support device is to use the resonance of a resonance circuit installed in the input support device to detect the input support device.
In an input detection system using such an input support device, the resonant frequency of the resonance circuit may change due to the parasitic capacitance between the input support device and the outside, for example, the parasitic capacitance formed between a housing and a finger or a palm of an operator.
An input detection system according to an embodiment of the present disclosure includes a plurality of electrodes arrayed in a detection region, and an input support device including an LC circuit, a first electrode coupled to one end side of the LC circuit, a second electrode coupled to another end side of the LC circuit, and a housing accommodating therein at least the LC circuit. The input support device is disposed overlapping with a plurality of the electrodes, the housing is a conductor, the LC circuit includes a first capacitor and a second capacitor coupled in series between the one end side and the other end side of the LC circuit, and a coupling portion between the first capacitor and the second capacitor is coupled to the housing.
An input support device according to an embodiment of the present disclosure includes an LC circuit, a first electrode coupled to one end side of the LC circuit, a second electrode coupled to another end side of the LC circuit, and a housing accommodating therein at least the LC circuit. The housing is a conductor, the LC circuit includes a first capacitor and a second capacitor coupled in series between the one end side and the other end side of the LC circuit, and a coupling portion between the first capacitor and the second capacitor is coupled to the housing.
Modes for carrying out the present disclosure (embodiments) will be described in detail with reference to the drawings. Contents described in the following embodiment do not limit the present disclosure. Components described below include those that can be easily assumed by those skilled in the art and substantially the same components. Furthermore, the components described below can be appropriately combined. What is disclosed herein is merely an example, and it is needless to say that appropriate modifications within the gist of the present disclosure at which those skilled in the art can easily arrive are encompassed in the scope of the present disclosure. In the drawings, widths, thicknesses, shapes, and the like of the components can be schematically illustrated in comparison with actual modes for clearer explanation. They are, however, merely examples and do not limit interpretation of the present disclosure. In the present disclosure and the drawings, the same reference numerals denote components similar to those described before with reference to the drawing that has already been referred, and detail explanation thereof can be appropriately omitted.
In the present specification and the scope of the claims, when a mode in which a second structure is arranged above a first structure is represented, simple expression “above” includes both the case in which the second structure is arranged immediately above the first structure in a manner contacting the first structure, and the case in which the second structure is arranged above the first structure with still a third structure interposed therebetween, unless otherwise specified.
One direction of a plane (upper surface 111a) of the display device 2 is a first direction Dx, and a direction orthogonal to the first direction Dx is a second direction Dy. The second direction Dy is not limited thereto and may intersect with the first direction Dx at an angle other than 90°. A third direction Dz orthogonal to the first direction Dx and the second direction Dy corresponds to the thickness direction of an array substrate SUB1.
As illustrated in
The array substrate SUB1 is a drive circuit substrate for driving a plurality of pixels PX. The array substrate SUB1 includes a first substrate 10 as a base body. The array substrate SUB1 includes switching elements Tr provided on the first substrate 10 and various wiring lines such as scan lines GL and pixel signal lines SL (see FIG. 4). The counter substrate SUB2 is provided so as to face the array substrate SUB1 and includes a second substrate 20 as a base body. The counter substrate SUB2 includes color filters CF and a light shielding layer BM (see
The length of the array substrate SUB1 in the second direction Dy is larger than the length of the counter substrate SUB2 in the second direction Dy. As illustrated in
As illustrated in
The display region DA is a region for displaying an image and is a region in which the pixels PX are provided. The peripheral region BE indicates a region on the inner side of the outer circumference of the array substrate SUB1 and on the outer side of the display region DA. The peripheral region BE may have a frame shape surrounding the display region DA, and in this case, the peripheral region BE can also be referred to as a frame region.
As illustrated in
A wiring substrate 115 is coupled to the counter substrate SUB2. A detection IC 51 is mounted on the wiring substrate 115. The detection IC 51 includes a detection circuit 55 (see
The wiring substrate 114 and the wiring substrate 115 are configured by flexible printed circuits (FPCs), for example. The wiring substrate 114 is coupled to a plurality of terminals of the first substrate 10. The wiring substrate 115 is coupled to a plurality of terminals of the second substrate 20.
As illustrated in
As illustrated in
In the following explanation, the housing 30 has a circular shape in a plan view with no through-hole in order to schematically illustrate the LC circuit 35. The shape of the housing 30 can, however, be appropriately modified, and the housing 30 may have an annular shape with a through-hole formed in a region overlapping with the rotating axis AX as illustrated in
The array substrate SUB1 faces the illumination device IL, and the counter substrate SUB2 is located on the display surface side. The illumination device IL emits light toward the array substrate SUB1. For example, a sidelight-type backlight or a direct-type backlight can be applied as the illumination device IL. Although various types of the illumination device IL can be applied, explanation of the detail configurations thereof is omitted.
An optical element including the first polarizing plate PL1 faces the first substrate 10. To be more specific, the first polarizing plate PL1 is arranged on the outer surface of the first substrate 10 or on the surface thereof facing the illumination device IL. An optical element including the second polarizing plate PL2 faces the second substrate 20. To be more specific, the second polarizing plate PL2 is arranged on the outer surface of the second substrate 20 or on the surface thereof on the observation position side. A first polarization axis of the first polarizing plate PL1 and a second polarization axis of the second polarizing plate PL2 have a crossed nicol positional relation in an X-Y plane, for example. The optical elements including the first polarizing plate PL1 and the second polarizing plate PL2 may include another optical function element such as a phase difference plate.
The array substrate SUB1 includes insulating films 11, 12, 13, 14, and 15, the pixel signal lines SL, pixel electrodes PE, the drive electrodes Tx (common electrodes CE), and a first orientation film AL1 on the side of the first substrate 10 that faces the counter substrate SUB2.
In the present specification, the direction toward the second substrate 20 from the first substrate 10 in the direction perpendicular to the first substrate 10 is an “upper-side direction” or simply an “upward direction”. The direction toward the first substrate 10 from the second substrate 20 is a “lower-side direction” or simply a “downward direction”. The expression “plan view” indicates a positional relation when seen from the direction perpendicular to the first substrate 10.
The insulating film 11 is provided above the first substrate 10. The insulating films 11, 12, and 13, and the insulating film 15 are inorganic insulating films made of, for example, an inorganic material having a light transmitting property, such as silicon oxide and silicon nitride.
The insulating film 12 is provided above the insulating film 11. The insulating film 13 is provided above the insulating film 12. The pixel signal lines SL are provided above the insulating film 13. The insulating film 14 is provided above the insulating film 13 and covers the pixel signal lines SL. The insulating film 14 is made of a resin material having a light transmitting property and has a film thickness that is thicker than those of the other insulating films made of the inorganic material. Although not illustrated in
The drive electrodes Tx are provided above the insulating film 14. The drive electrodes Tx are provided in the display region DA and are divided into a plurality of parts by slits. The drive electrodes Tx are covered with the insulating film 15. The drive electrodes Tx serve as the drive electrodes Tx for touch detection and the common electrodes CE in display.
The pixel electrodes PE are provided above the insulating film 15 and face the drive electrodes Tx with the insulating film 15 interposed therebetween. The pixel electrodes PE and the drive electrodes Tx are made of, for example, a conductive material having a light transmitting property, such as indium tin oxide (ITO) or indium zinc oxide (IZO). The first orientation film AL1 covers the pixel electrodes PE and the insulating film 15.
The counter substrate SUB2 includes the light shielding layer BM, color filters CFR, CFG, and CFB, an overcoat layer OC, a second orientation film AL2 and the like on the side of the second substrate 20 that faces the array substrate SUB1. The counter substrate SUB2 includes the detection electrodes Rx and the second polarizing plate PL2 on the side of the second substrate 20 that is opposite to the array substrate SUB1.
The light shielding layer BM is located on the second substrate 20 on the side facing the array substrate SUB1 in the display region DA. The light shielding layer BM defines openings that respectively face the pixel electrodes PE. The pixel electrodes PE are partitioned for the respective openings of the pixels PX. The light shielding layer BM is made of a resin material in black color or a metal material having a light shielding property.
The color filters CFR, CFG, and CFB are located on the second substrate 20 on the side facing the array substrate SUB1, and end portions thereof overlap with the light shielding layer BM. As an example, the color filters CFR, CFG, and CFB are made of a resin material colored in red, green, and blue, respectively.
The overcoat layer OC covers the color filters CFR, CFG, and CFB. The overcoat layer OC is made of a resin material having a light transmitting property. The second orientation film AL2 covers the overcoat layer OC. The first orientation film AL1 and the second orientation film AL2 are made of, for example, a material exhibiting horizontal orientation performance.
The detection electrodes Rx are provided above the second substrate 20. The detection electrodes Rx are, for example, metal wiring formed of a conductive material. The detection electrodes Rx may be made of a conductive material having a light transmitting property, such as ITO.
The array substrate SUB1 and the counter substrate SUB2 are arranged such that the first orientation film AL1 and the second orientation film AL2 face each other. The liquid crystal layer LC is enclosed into between the first orientation film AL1 and the second orientation film AL2. The liquid crystal layer LC is made of a negative liquid crystal material having a negative dielectric anisotropy or a positive liquid crystal material having a positive dielectric anisotropy.
For example, when the liquid crystal layer LC is made of the negative liquid crystal material and a state in which no voltage is applied to the liquid crystal layer LC is established, liquid crystal molecules LM are initially oriented in such a direction that long axes thereof are along the first direction Dx in the X-Y plane. On the other hand, in a state in which the voltage is applied to the liquid crystal layer LC, that is, in an ON state in which an electric field is formed between the pixel electrodes PE and the drive electrodes Tx, the liquid crystal molecules LM receive influences of the electric field and orientation states thereof are changed. In the ON state, a polarization state of incident linearly polarized light is changed in accordance with the orientation states of the liquid crystal molecules LM when the light passes through the liquid crystal layer LC.
Each pixel PX includes the sub pixels SPX. Each sub pixel SPX includes the switching element Tr and capacitance of the liquid crystal layer LC. The switching element Tr is formed by a thin film transistor and, in this example, is formed by an n-channel metal oxide semiconductor (MOS) TFT. The insulating film 15 is provided between the pixel electrodes PE and the drive electrodes Tx illustrated in
Color regions colored in three colors of red (R), green (G), and blue (B), for example, are periodically arrayed as the color filters CFR, CFG, and CFB. The color regions of the three colors of R, G, and B as one set are made to respectively correspond to the sub pixels SPX. A set of sub pixels SPX corresponding to the color regions of the three colors configures a pixel PX. The color filters may include color regions of equal to or more than four colors. In this case, the pixel PX may include equal to or more than four sub pixels SPX.
The drive electrodes Tx extend in the second direction Dy and are aligned in the first direction Dx. The drive electrodes Tx are coupled to the display IC 50 through coupling wiring lines 53A. The detection electrodes Rx extend in the first direction Dx and are aligned in the second direction Dy. The detection electrodes Rx are coupled to the detection IC 51 through coupling wiring lines 53B. The drive electrodes Tx and the detection electrodes Rx intersect with each other in a plan view. Electrostatic capacitances are formed in intersecting portions between the drive electrodes Tx and the detection electrodes Rx. The detection IC 51 can detect the object to be detected based on the detection signals Vdet that are output in accordance with change in mutual electrostatic capacitances between the drive electrodes Tx and the detection electrodes Rx.
Although
The drive electrodes Tx serve as the common electrodes CE in display and as the drive electrodes Tx for detecting an object to be detected such as a finger Fg and the input support device 3. To be specific, the display IC 50 supplies a display drive signal VCOM to the drive electrodes Tx in display. The display IC 50 includes at least a drive signal supply circuit 56. The drive signal supply circuit 56 supplies a detection drive signal VD to the drive electrodes Tx sequentially.
To be specific, in touch detection of detecting the position of the finger Fg, the display IC 50 (drive signal supply circuit 56) supplies the detection drive signal VD to the drive electrodes Tx, and the detection signals Vdet based on the change in the mutual electrostatic capacitances are output to the detection IC 51. The detection IC 51 thereby detects contact or proximity of the finger Fg.
In detection of the input support device 3, the display IC 50 (drive signal supply circuit 56) supplies the detection drive signal VD to the drive electrodes Tx, and the detection IC 51 detects a position and the like of the input support device 3 using the change in the mutual electrostatic capacitances and resonance of the LC circuit 35 included in the input support device 3.
Next, a method for detecting the input support device 3 will be described with reference to
The capacitor 33 included in the LC circuit 35 includes a first capacitor 33A and a second capacitor 33B coupled in series. A coupling portion N3 between the first capacitor 33A and the second capacitor 33B is coupled to the housing 30 through a coupling member 37.
In the LC circuit 35, the first capacitor 33A and the second capacitor 33B are coupled in series in this order, between the coupling portion N1 on the one end side and the coupling portion N2 on the other end side of the LC circuit 35. The inductor 34 is coupled in parallel with the first capacitor 33A and the second capacitor 33B coupled in series. The coupling portion N3 between the first capacitor 33A and the second capacitor 33B is coupled to the housing 30 through the coupling member 37. The coupling member 37 is, for example, wiring formed by a conductor. Any shape and configuration of the coupling member 37 may be employed as long as the coupling member 37 can electrically couple the coupling portion N1 and the housing 30. The LC circuit 35 may have a resistive component such as the inductor 34, and may also have additional resistive elements in addition to the first capacitor 33A, the second capacitor 33B, and the inductor 34.
When the operator operates the input support device 3, the finger Fg or the palm thereof comes into contact with the housing 30. The coupling portion N3 between the first capacitor 33A and the second capacitor 33B of the LC circuit 35 is thereby coupled to the reference potential GND through the coupling member 37 and the housing 30. The reference potential GND is, for example, a ground potential. The reference potential GND is, however, not limited thereto and may be a predetermined fixed potential. A configuration in which the outside of the housing 30 is covered with resin or other materials can also be employed. In such a configuration, the housing 30 is capacitively coupled to the finger or the palm that contacts the resin.
The input support device 3 is arranged so as to overlap with a plurality of the drive electrodes Tx and a plurality of the detection electrodes Rx. A capacitance C1 is formed between the first electrode 31 and one of the drive electrodes Tx (the drive electrode Tx on the left in
A capacitance C3 is formed between the second electrode 32 and the detection electrode Rx facing the second electrode 32. The detection electrode Rx is coupled to the detection circuit 55 or the reference potential GND (for example, ground potential) through a switch element 54A. Mutual electrostatic capacitance Cm is further formed between the drive electrode Tx and the detection electrode Rx. A capacitance C4 is formed between the first electrode 31 and the detection electrode Rx facing the first electrode 31.
The detection circuit 55 is a signal processing circuit provided in a detection IC 51, and receives the detection signal Vdet (see
As illustrated in
The detection electrode Rx outputs the detection signal Vdet based on the mutual electrostatic capacitance Cm. To be specific, as described above, the one drive electrode Tx is coupled to the reference potential (for example, reference potential Vdc) in both the first period P1 and the second period P2. In the first period P1, signals of different potentials are thereby supplied to the first electrode 31 and the second electrode 32. In the first period P1, the detection electrode Rx is coupled to the detection circuit 55 by the switching operation of the switch element 54A. With this coupling, variation in potential based on the mutual electrostatic capacitance Cm is output as the detection signal Vdet from the detection electrode Rx to the detection circuit 55. In the second period P2, the coupling between the detection electrode Rx and the detection circuit 55 is cut off by the switching operation of the switch element 54A. In the second period P2, the detection electrode Rx is coupled to the reference potential (or ground potential GND) by the switching operation of the switch element 54A.
The detection signal amplifier 61 of the detection circuit 55 amplifies the detection signal Vdet supplied from the detection electrode Rx. Reference voltage having a fixed potential is input to a non-inversion input portion of the detection signal amplifier 61, and the detection electrode Rx is coupled to an inversion input terminal thereof. In the embodiment, the same signal as the signal of the one drive electrode Tx is input as the reference voltage. The detection circuit 55 can reset a charge of the capacitive element 62 by turning the reset switch 63 ON.
The detection drive signal VD has the same frequency as the resonant frequency of the LC circuit 35. In this example, for example, the detection drive signal VD having a resonant frequency is formed by performing the switching operation of the switch element 54B based on the resonant frequency. Accordingly, the second electrode 32 overlapping with the other drive electrode Tx is also driven at the resonant frequency, and the resonance of the LC circuit 35 is generated. With this resonance, as the first periods P1 and the second periods P2 are repeated, the amplitude of the detection signal Vdet is increased. As illustrated in
On the other hand, when an object to be detected such as the finger Fg differing from the input support device 3 comes into contact with or close to the upper surface 111a (see
As illustrated in
The coupling portion N3 between the first capacitor 33A and the second capacitor 33B does not generate any variation in potential due to the resonance of the LC circuit 35. In other words, as the first periods P1 and the second periods P2 are repeated, the amplitude of the detection signals Vdet of the first electrode 31 and the second electrode 32 increases, while the voltage waveform at the coupling portion N3 has a constant amplitude.
The LC circuit 35 is shielded by the housing 30 as described above. Furthermore, since the housing 30 is coupled to the coupling portion N3, the coupling portion N3 and the housing 30 are coupled to the reference potential when the finger Fg or the palm contacts the housing 30 of the input support device 3 as described above. This configuration can suppress change in the capacitance formed on the LC circuit 35 side even when parasitic capacitance is formed between the housing 30 and the outside (for example, an operator's finger Fg or palm). The capacitance formed on the LC circuit 35 side includes the capacitance formed between the first electrode 31 and the coupling portion N3, and the capacitance formed between the second electrode 32 and the coupling portion N3. Thus, the input support device 3 can mitigate variation in the resonant frequency of the LC circuit 35 even when parasitic capacitance is formed between the housing 30 and the finger Fg or the like. As a result, a decrease in the detection signal Vdet caused by a change in the resonant frequency of the LC circuit 35 can be suppressed, and the detection accuracy of the input support device 3 can be improved. Alternatively, since changes in the resonant frequency of the LC circuit 35 can be suppressed, correction of the drive frequency of the detection drive signal VD is not necessary, and the circuit configuration of the display IC 50 including the drive signal supply circuit 56 can be simplified.
The ratio of a capacitance value CA of the first capacitor 33A to a capacitance value CB of the second capacitor 33B is equal to the ratio of an area S1 of the first electrode 31 (see
CA:CB=S1:S2 (1)
In other words, the ratio of the capacitance value CA of the first capacitor 33A to the capacitance value CB of the second capacitor 33B is equal to the ratio of an interelectrode capacitance CE1 (the total capacitance value of the capacitance C1 and the capacitance C4) formed between the first electrode 31 and a plurality of electrodes (drive electrode Tx and detection electrode Rx) facing the first electrode 31 to an interelectrode capacitance CE2 (the total capacitance value of the capacitance C2 and the capacitance C3) formed between the second electrode 32 and a plurality of electrodes (drive electrode Tx and detection electrode Rx) facing the second electrode 32. In other words, the capacitance value CA of the first capacitor 33A and the capacitance value CB of the second capacitor 33B satisfy the relation in Equation (2) below.
CA:CB=CE1:CE2 (2)
When the first capacitor 33A and the second capacitor 33B satisfy the relation in Equation (1) or Equation (2), the input support device 3 can suppress the change in potential at the coupling portion N3 due to the resonance of the LC circuit 35.
The width of the drive electrode Tx is smaller than the distance between the first electrode 31 and the second electrode 32 that are placed opposite each other across the rotation axis AX. Thus, the first electrode 31 and the second electrode 32 are arranged overlapping with different drive electrodes Tx, and the drive electrode Tx overlapping with the first electrode 31 (the one drive electrode Tx) is supplied with the reference potential Vdc, and the drive electrode Tx overlapping with the second electrode 32 (the other drive electrode Tx) is supplied with the detection drive signal VD. As a result, the second electrode 32 can increase the amplitude of the detection signal Vdet using the resonance of the resonance of the LC circuit 35.
The drive signal supply circuit 56 may supply the detection drive signal VD to a plurality of adjacent drive electrodes Tx simultaneously, and drive each drive electrode block consisting of a plurality of adjacent drive electrodes Tx. The drive electrode Tx supplied with the detection drive signal VD from the drive signal supply circuit 56 changes accordingly in a time-divisional manner. For example, in the predetermined first detection period, the above-mentioned other drive electrode Tx is coupled to the drive signal supply circuit 56, and in the next second detection period, the coupling between the other drive electrode Tx and the drive signal supply circuit 56 is cut off, and the drive electrode Tx next to the other drive electrode Tx is coupled to the drive signal supply circuit 56. These drive electrodes Tx also function as the common electrodes of the display device. If that period is referred to as a display period, the display period may be provided between the first detection period and the second detection period, or a configuration may be employed in which the second detection period is provided immediately after the first detection period, followed by the display period. When there are N drive electrodes Tx, and the above-mentioned other drive electrode Tx is driven in the first detection period, the drive electrode Tx next to the other drive electrode Tx in the second detection period, the drive electrode Tx that is two electrodes away from the other drive electrode Tx in the third detection period, and the Nth drive electrode Tx in the Nth period, and so on, the display period may be provided after the Nth detection period from the first detection period. A configuration can also be adopted in which the first to the Nth detection periods are divided into multiple periods and the display period is provided between those periods. As for the display period, a configuration in which display in the entire display area is refreshed in the display period can be adopted, or a configuration in which a portion of the display area is refreshed in the display period can be adopted.
Next, a method for detecting the input support device 3 and an object to be detected such as the finger Fg or the like, which is different from the input support device 3, in the input detection system 1, is described.
Then, the calculation circuit calculates a differential value of at least two detection values R based on the output signals Vo received from the detection circuit 55 (step ST12). The calculation circuit may divide the detection values R1, R2, R3, . . . , and Rn into two groups to calculate a difference between the total of one group of the detection values R and the total of the other group of the detection values R, for example.
Subsequently, the calculation circuit calculates addition values of at least two detection values R based on the output signals Vo received from the detection circuit 55 (step ST13). The calculation circuit may calculate an addition value by summing up the detection values R1, R2, R3, . . . , and Rn, for example.
The calculation circuit determines whether the input support device 3 is detected (step ST14). To be specific, the calculation circuit compares the differential values acquired at step ST12 and a first detection reference value previously stored in a storage circuit. When any of the differential values is equal to or larger than the first detection reference value, that is, when the input support device 3 is detected (Yes at step ST14), the calculation circuit calculates the position of the input support device 3 and the angle (rotation operation RT) of the input support device 3 (step ST15).
Then, the calculation circuit detects whether the finger Fg contacts the input support device 3 (step ST16). As described above, the input support device 3 is shielded by the coupling portion N3, and thus the amplitude of the detection signal Vdet does not change even if parasitic capacitance is formed between the housing 30 and, for example, the operator's finger Fg or palm. In other words, even if parasitic capacitance is formed between the housing 30 and the finger Fg, the voltage applied between the coupling portion N1 of the LC circuit 35 on the one end side and the coupling portion N2 of the LC circuit 35 on the other end side will not change. Therefore, the increase in the amplitude of the detection signal Vdet (see
On the other hand, if parasitic capacitance is formed between the housing 30 and the finger Fg, the charge supplied to the coupling portion N2 of the LC circuit 35 on the other end side (the capacitance C3 between the second electrode 32 and the detection electrode Rx) will change. In other words, the baseline of the output signal Vo changes. Based on the difference of the baseline, the calculation circuit can detect whether the finger Fg has made contact with the input support device 3. Therefore, the calculation circuit can detect the contact of the finger Fg with the input support device 3 based on a signal (baseline difference) that is different from the detection values R1, R2, R3, . . . , Rn, without affecting the detection of the input support device 3.
Then, the calculation circuit determines whether touch of the object to be detected such as the finger Fg is detected (step ST17). To be specific, the calculation circuit compares the addition values acquired at step ST13 and a second detection reference value previously stored in the storage circuit. When any of the addition values is equal to or larger than the second detection reference value, that is, when touch of the object to be detected such as the finger Fg is detected (Yes at step ST17), the calculation circuit calculates the position of the object to be detected such as the finger Fg (step ST18).
When the addition values are smaller than the second detection reference value, that is, when touch of the object to be detected such as the finger Fg is not detected (No at step ST17), the calculation circuit omits calculation of the position of the object to be detected such as the finger Fg. The calculation circuit outputs calculation results (information related to the input support device 3 and touch detection information of the finger Fg or the like) to an external host IC and finishes detection for one frame.
The detection method illustrated in
As described above, the input detection system 1 includes the electrodes (drive electrodes Tx and detection electrodes Rx) arrayed in the detection region (display region DA), and the input support device 3 including the LC circuit 35, the first electrode 31 coupled to the one end side of the LC circuit 35, the second electrode 32 coupled to the other end side of the LC circuit 35, and the housing 30 accommodating therein at least the LC circuit 35. The input support device 3 is disposed overlapping with the electrodes (drive electrodes Tx and detection electrodes Rx), the housing 30 is a conductor, the LC circuit 35 includes the first capacitor 33A and the second capacitor 33B coupled in series between the one end side and the other end side of the LC circuit 35, and the coupling portion N3 between the first capacitor 33A and the second capacitor 33B is coupled to the housing 30.
In this way, the LC circuit 35 of the input support device 3 is shielded by the coupling portion N3 and the housing 30. Furthermore, since the housing 30 is coupled to the coupling portion N3, the coupling portion N3 and the housing 30 are coupled to the reference potential when the finger Fg or the palm contacts the housing 30 of the input support device 3 as described above. This can suppress change in the resonant frequency of the LC circuit 35 even when parasitic capacitance is formed between the housing 30 and the outside (for example, the operator's finger Fg or palm). Since the input detection system 1 can suppress the change in the resonant frequency of the LC circuit 35, the correction of the drive frequency of the detection drive signal VD is unnecessary, and the circuit configuration of the display IC 50 including the drive signal supply circuit 56 can be simplified.
In the first embodiment described above, parasitic capacitances Cp1 and Cp2 formed in the LC circuit 35 are omitted for the sake of clarity of explanation. In the input support device 3a of the first modification, the capacitance value CA of the first capacitor 33A and the capacitance value CB of the second capacitor 33B are explained when the parasitic capacitances Cp1 and Cp2 are considered, as illustrated in
In the first modification, the capacitance value CA of the first capacitor 33A and the capacitance value CB of the second capacitor 33B satisfy the relation in Equation (2) below.
CA+Cp1:CB+Cp2=CE1:CE2 (3)
However, the interelectrode capacitances CE1 and CE2 are the same as those in the first embodiment described above. The interelectrode capacitance CE1 is the capacitance value formed in the first electrode 31 (the total capacitance value of the capacitance C1 and the capacitance C4), and the interelectrode capacitance CE2 is the capacitance value formed in the second electrode 32 (the total capacitance value of the capacitance C2 and the capacitance C3).
Considering the parasitic capacitances Cp1 and Cp2, when the first capacitor 33A and the second capacitor 33B satisfy the relation in Equation (3), the input support device 3a can suppress change in potential due to resonance of the LC circuit 35 at the coupling portion N3. Equation (3) present the ratio of the interelectrode capacitance CE1 to the interelectrode capacitance CE2; however, it can also presents the ratio of the area S1 of the first electrode 31 to the area S2 of the second electrode 32, as in Equation (1) above.
In the first embodiment and the first modification described above, a configuration is described in which the shape and the area S1 of the first electrode 31 are the same as the shape and the area S2 of the second electrode 32; however, the shape and the area are not limited thereto. The following describes a configuration in which the shapes of the first electrode 31 and the second electrodes 32 are different in an input support device 3b of the second modification.
As illustrated in
Since the shape and the area S1 of the first electrode 31 are different from the shape and the area S2 of the second electrode 32, even when the first electrode 31 and the second electrode 32 are placed side by side along an extension direction of the drive electrodes Tx by a rotation operation of the input support device 3b, at least a part of the second electrode 32 overlaps with a drive electrode Tx that is different from the drive electrode Tx overlapping with the first electrode 31. Therefore, the input detection system 1 can supply signals of different potentials to the first electrode 31 and the second electrode 32, regardless of the direction of rotation of the input support device 3b.
The first electrode 31 and the second electrode 32 are not limited to circular or L-shaped, and other shapes can be adopted. For example, the first electrode 31 and the second electrode 32 may be elliptical, oval, rectangular, polygonal, or another shape.
The above-described first embodiment, first modification, and second modification describe examples of the input support device 3 arranged above the mutual electrostatic capacitance type touch sensor (display device 2) including the drive electrodes Tx and the detection electrodes Rx; however, the disclosure is not limited thereto. The touch sensor (display device 2) may be of self electrostatic capacitance type (self type).
Sensor wiring lines 58 are provided so as to correspond to the respective detection electrodes DE and are coupled to the detection electrodes DE through contact holes CN. The sensor wiring lines 58 extend along the second direction Dy and are aligned in the first direction Dx. The sensor wiring lines 58 and the pixel signal lines SL are coupled to the display IC 50 provided in the peripheral region BE.
The detection electrodes DE serve as common electrodes in display and the drive electrodes Tx and the detection electrodes Rx for detecting the input support device 3 and an object to be detected such as a finger Fg. The display IC 50 may also have the functions of the detection IC 51 illustrated in
The display IC 50 supplies the display drive signal VCOM to the detection electrodes DE in display. In the detection of an object to be detected such as the input support device 3 or the finger Fg, the drive signal supply circuit 56 of the display IC 50 supplies the detection drive signal VD to the detection electrodes DE through the sensor wiring lines 58. The detection electrodes DE output the detection signals Vdet through the sensor wiring lines 58 based on the change in the self electrostatic capacitances of the detection electrodes DE and the resonance of the LC circuit 35. The display IC 50 (or detection IC 51) detects the input support device 3 or an object to be detected such as the finger Fg based on the detection values R (output signals Vo) obtained by signal processing on the detection signals Vdet.
In the self electrostatic capacitance type touch detection, the touch sensor (display device 2) can detect the finger Fg or the like by supplying detection drive signal VD to all detection electrodes DE. On the other hand, in the detection of the input support device 3, the detection drive signal VD is sequentially supplied to the detection electrodes DE so as to generate the resonance of the LC circuit 35.
Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments. Contents disclosed in the embodiments are merely examples, and various modifications can be made in a range without departing from the gist of the present disclosure. It is needless to say that appropriate modifications in a range without departing from the gist of the present disclosure belong to the technical scope of the present disclosure.
At least one of various omission, replacement, and modification of the components can be performed in a range without departing from the gist of the embodiments and modifications described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-188781 | Nov 2020 | JP | national |
