JP2014130525A - Tactile sense presentation device and tactile display device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tactile sense presentation device capable of driving at low power consumption a tactile sense presentation element that presents a tactile sense by an electric stimulus.SOLUTION: A tactile sense presentation device includes: a tactile sense presentation element (for example, a tactile sense presentation element including a counter electrode 25) that presents a tactile sense by an electric stimulus: and a driving unit that drives the tactile sense presentation element. The driving unit includes thin-film transistors (for example, a first thin-film transistor 23 and a second thin-film transistor 24) that use a metal oxide semiconductor.

Description

  The present invention relates to a tactile presentation device that presents tactile stimulation and a tactile display device including the same.

  Various means such as a cathode ray tube display device, a liquid crystal display device, and an organic EL display device are used as means for transmitting information to human vision. However, due to an increase in the amount of information to be transmitted and the complexity of the information content to be transmitted, the user may not be able to immediately understand the information with only visual information. Such a tendency is particularly prominent in elderly people whose visual functions and cognitive functions have declined.

  Therefore, in recent years, as a user-friendly means for transmitting information to human beings, a tactile display device that transmits information visually also by presenting tactile stimulation to a user's body part (mainly a finger). Has been actively studied.

  In particular, by adding a function for presenting tactile stimulation to a touch panel display device whose display screen surface is usually uniform, it is possible to present tactile stimulation when a user performs a screen touch operation. Thus, it is possible to give easily understandable information to the user who performs the screen touch operation. For example, it is possible to give auxiliary information such as operation guidance, operation completion, and warning for an incorrect operation to a user who performs a screen touch operation.

JP 2009-87359 A

Hiroyuki Enomoto and 1 other "Sense stabilization in high-density, large-area electrotactile display", Proceedings of the 20th Symposium on Biological and Physiological Optics

  In the tactile display device described above, an increase in power consumption due to the addition of a function for presenting tactile stimulation becomes a problem.

  For example, Patent Document 1 provides a method and apparatus that can change a touch screen input into a dynamic texture input. This method and apparatus forms a capacitive coupling via an insulator between a fingertip and a conductive electrode formed on a touch panel, and applies electrical stimulation to the fingertip by changing the strength of this capacitive coupling. . Here, in order to stimulate the Patini body, which is one of the receptors under the skin of the fingertip, by changing the strength of the capacitive coupling, a voltage of several tens to several hundreds V generated by the high voltage generation circuit is used. It is necessary to store the charge by applying it to a predetermined conducting electrode via the switching matrix. Note that the switching matrix uses a thin film transistor that is a semiconductor switch that can be directly formed on the panel, so that durability can be improved and control can be facilitated as compared to the case where a relay switch is used.

  However, when voltage application to the conducting electrode is controlled by the thin film transistor formed on the panel, the charge accumulated in the conducting electrode is discharged by the off-leakage current of the thin film transistor even when the thin film transistor is turned off, and presents a tactile stimulus. Function will be reduced. Therefore, in order to prevent a decrease in the function of presenting the tactile stimulus, the conductive electrode is refreshed at intervals of several Hz to several tens Hz to retain the electric charge accumulated in the conductive electrode. In particular, as the size of the touch panel increases, the number of thin film transistors increases accordingly, and power consumption due to refresh becomes enormous.

  In addition, for example, Non-Patent Document 1 proposes a tactile display device that presents tactile stimulation by passing a weak current through the skin and stimulating nerves. Similarly to this tactile display device, a plurality of electrodes (transparent electrodes) are formed on the touch panel, a voltage is applied between predetermined electrodes (between the stimulation electrode and the ground electrode), and current is passed through the percutaneous. By flowing, tactile stimulation can be presented during a screen touch operation.

  However, as with the capacitive coupling method used in the method and apparatus provided in Patent Document 1 described above, as the size of the touch panel increases, the number of electrodes formed on the touch panel increases. Since the number of switching transistors that drive the electrodes also increases, the power consumption due to the off-leak current of the switching transistor increases as the off-leak current of the switching transistor cannot be ignored.

  In view of the above situation, an object of the present invention is to provide a tactile presentation device that can drive a tactile presentation element that presents a tactile sense by electrical stimulation with low power consumption, and a tactile display device including the tactile presentation device.

  In order to achieve the above object, a tactile presentation device according to the present invention includes a tactile presentation element that presents a tactile sense by electrical stimulation, and a drive unit that drives the tactile presentation element, and the drive unit is a metal oxide semiconductor. A configuration including a thin film transistor using the above (first configuration).

  According to such a structure, since the driving unit includes a thin film transistor using a metal oxide semiconductor, the off-leak current of the thin film transistor can be reduced, and power consumption due to the off-leak current of the thin film transistor can be significantly reduced. Therefore, the tactile sense presentation element can be driven with low power consumption.

  In the tactile sensation presentation apparatus having the first configuration, the metal oxide semiconductor preferably includes at least indium, gallium, and zinc (second configuration).

  According to such a structure, the thin film transistor can be formed by a low-temperature film formation process.

  In the tactile sense presentation device having the second configuration, it is preferable that the metal oxide semiconductor has a configuration (third configuration) containing indium, gallium, zinc, and oxygen as main components.

  According to such a structure, the thin film transistor can be formed by a low-temperature film formation process.

  In the tactile sensation providing apparatus having the first configuration, it is preferable that the metal oxide semiconductor has a configuration (fourth configuration) containing any element of indium, gallium, zinc, and tin.

  According to such a structure, the thin film transistor can be formed by a low-temperature film formation process.

  In the tactile sensation presentation apparatus having any one of the first to fourth configurations, the tactile sensation presentation element includes an electrode and an insulator provided on the electrode, and is provided between the electrode and a body part of the user. When capacitive coupling through the insulator is formed, a tactile sensation is applied to the body part of the user due to an electrostatic force generated between the electric charge accumulated in the electrode and the electric charge charged in the user part. It is preferable to adopt a configuration to be presented (fifth configuration).

  According to such a configuration, when a capacitive coupling through the insulator is formed between the electrode and a user's body part, the electrostatic force is generated by moving the user's body part. Therefore, for example, although the user's finger flicks a smooth surface, a different texture sensation can be generated.

  In the tactile sensation presentation device having any one of the first to fifth configurations, the tactile sensation presentation element is provided in plural, and the driving unit includes a plurality of charge pump circuits including at least one capacitor and at least one transistor, It is preferable that the tactile sense providing element and the charge pump circuit have a one-to-one correspondence (sixth configuration).

  According to such a structure, an applied voltage can be adjusted for every said tactile sense presentation element.

  In order to achieve the above object, a tactile display device according to the present invention includes a display unit having a plurality of pixels and the tactile display device having any one of the first to sixth configurations (seventh configuration). And

  In the tactile display device having the seventh configuration, the pixel preferably includes a liquid crystal element or an organic EL element (eighth configuration).

  According to such a configuration, the display unit can be thinned.

  According to the present invention, since the driving unit that drives the tactile sensation display element that presents a tactile sensation by electrical stimulation includes the thin film transistor using the metal oxide semiconductor, the off leak current of the thin film transistor can be reduced and the consumption due to the off leak current of the thin film transistor Electric power can be greatly reduced. Therefore, the tactile sense presentation element can be driven with low power consumption.

1 is a perspective view showing a schematic configuration of a tactile display device according to a first embodiment of the present invention. It is a front view which shows schematic structure of the tactile display apparatus which concerns on 1st of this invention. It is a figure which shows the circuit structural example of a transmissive liquid crystal display panel. It is a figure which shows the circuit structural example of a tactile-function panel. It is a figure which shows the cross-sectional structural example of a tactile sense presentation element, a 1st thin-film transistor, and a 2nd thin-film transistor. It is a figure which shows the gate voltage-drain current characteristic example of a thin-film transistor. It is a figure which shows the circuit structural example of the haptic function panel used with the haptic display apparatus which concerns on the 2nd of this invention. It is a figure which shows the structural example of a charge pump. It is a figure which shows the circuit structural example of the haptic function panel used with the haptic display apparatus which concerns on the 3rd of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
The tactile display device according to the first embodiment of the present invention includes a transmissive liquid crystal display panel 1, a haptic function panel 2 provided on the transmissive liquid crystal display panel 1, and a protective layer 3 provided on the haptic function panel 2. (Refer to FIG. 1). The tactile display device according to this embodiment is connected to the signal electrode drive circuit 11 and the scan electrode drive circuit 12 provided in the transmissive liquid crystal display panel 1 and controls the signal electrode drive circuit 11 and the scan electrode drive circuit 12. A transmissive liquid crystal display panel drive circuit 4 is provided. The tactile display device according to this embodiment is connected to the X-direction multiplexer circuit 21 and the Y-direction multiplexer circuit 22 provided in the tactile function panel 2 and controls the X-direction multiplexer circuit 21 and the Y-direction multiplexer circuit 22. A panel drive circuit 5 is provided. The tactile display device according to the present embodiment also includes a backlight unit (not shown) that irradiates the back surface of the transmissive liquid crystal display panel 1 with planar light.

  The transmissive liquid crystal display panel 1 has a display screen size of 18 cm diagonal and a pixel count of 1024 (× RGB) × 600. However, these numerical values are merely examples, and other values may be used.

  The tactile function panel 2 includes 256 × 150 tactile sense presenting elements in a matrix in a row direction and a column direction on a translucent substrate (for example, a glass substrate). However, this numerical value is merely an example, and other values may be used. In the present embodiment, one tactile sensation providing element is assigned to 4 (× RGB) × 4 pixels. The tactile function panel 2 substantially transmits visible light so that the user can visually recognize the display screen of the lower transmissive liquid crystal display panel 1.

  A circuit configuration example of the transmissive liquid crystal display panel 1 is shown in FIG. Each signal line L1 is connected to the signal electrode drive circuit 11, and each scan line L2 and each common line L3 are connected to the scan electrode drive circuit 12. The first electrode (signal electrode) of the thin film transistor 13 is connected to the signal line L1, and the gate electrode (scanning electrode) of the thin film transistor 13 is connected to the scanning line L2. The second electrode of the thin film transistor 13 is connected to the pixel electrode of the liquid crystal element 14 and one end of the additional capacitor 15. The counter electrode of the liquid crystal element 14 is connected to the common electrode 16, and the other end of the additional capacitor 15 is connected to the common line L3. A liquid crystal layer (not shown) is provided between the pixel electrode and the counter electrode of the liquid crystal element 14.

  An example of the circuit configuration of the tactile function panel 2 is shown in FIG. Each first control line L 4 and each second control line L 5 are connected to the X-direction multiplexer circuit 21, and each first voltage supply line L 6 and each second voltage supply line L 7 are connected to the Y-direction multiplexer circuit 22. The first electrode of the first thin film transistor 23 is connected to the first voltage supply line L6, and the gate electrode of the first thin film transistor 23 is connected to the first control line L4. The first electrode of the second thin film transistor 24 is connected to the second voltage supply line L7, and the gate electrode of the second thin film transistor 24 is connected to the second control line L5. The second electrode of the first thin film transistor 23 and the second electrode of the second thin film transistor 24 are connected to the counter electrode 25 of the tactile sense presentation element.

  The X-direction multiplexer circuit 21 supplies a first control signal for turning on the first thin film transistor 23 to an arbitrary first control line L4, and turns on the second thin film transistor 24 to an arbitrary second control line L5. A second control signal is supplied to The Y-direction multiplexer circuit 22 supplies a first voltage to an arbitrary first voltage supply line L6 and supplies a second voltage (for example, a ground voltage) lower than the first voltage to an arbitrary second voltage supply line L7.

  When the first voltage is supplied to the first electrode and the first control signal is supplied to the gate electrode, the first thin film transistor 23 is turned on, and when the second control signal is not supplied to the gate electrode, the second thin film transistor 24 is turned on. In the off state, the first voltage is applied to the counter electrode 25 of the tactile sense presentation element. On the contrary, the first thin film transistor 23 is turned off by the non-supply of the first control signal to the gate electrode, and the second is supplied by the supply of the second voltage to the first electrode and the supply of the second control signal to the gate electrode. When the thin film transistor 24 is turned on, a second voltage (for example, a ground voltage) lower than the first voltage is applied to the counter electrode 25 of the tactile sense presentation element. Further, by turning off both the first thin film transistor 23 and the second thin film transistor 24, the counter electrode 25 of the tactile sensation providing element can be electrically disconnected from the first voltage supply line L6 and the second voltage supply line L7.

  The first voltage is applied to the counter electrode 25 of the tactile presentation element, and then both the first thin film transistor 23 and the second thin film transistor 24 are turned off, and charge is accumulated in the counter electrode 25 of the tactile presentation element. When capacitive coupling is formed between the counter electrode 25 of the element and the user's body part (mainly a finger), the charge having a polarity opposite to that of the charge accumulated in the counter electrode 25 of the tactile sense presenting element is obtained by the user. Induced under the skin of body parts. Which tactile sensation-presenting element is applied with the first voltage may be determined according to, for example, image information displayed on the transmissive liquid crystal display panel 1.

  Here, FIG. 5 shows an example of a cross-sectional structure of the tactile sense providing element, the first thin film transistor 23, and the second thin film transistor 24. In the cross-sectional structure example shown in FIG. 5, the first thin film transistor 23 and the second thin film transistor 24 are bottom-gate thin film transistors, and the tactile sensation providing element is configured by a counter electrode 25 and a region corresponding to the counter electrode 25 of the insulating layer 112. Has been.

  Gate electrodes 102 and 103 are formed by forming a metal layer on a light-transmitting insulating substrate 101 such as a glass substrate and patterning the metal layer. After that, an insulating layer is formed, and the insulating layer is patterned, whereby the gate insulating layer 104 that covers the gate electrode 102 and the gate insulating layer 105 that covers the gate electrode 103 are formed.

  Subsequently, a counter electrode 25 is formed by forming a metal layer and patterning the metal layer. After that, an amorphous oxide semiconductor layer containing at least indium, gallium, and zinc (more preferably, an amorphous oxide semiconductor layer containing indium, gallium, zinc, and oxygen as main components) is formed by a sputtering method, and the amorphous oxidation is performed. By patterning the physical semiconductor layer, metal oxide semiconductor layers 106 and 107 to be channel regions are formed. Note that instead of an amorphous oxide semiconductor layer containing at least indium, gallium, and zinc, another metal oxide semiconductor layer, for example, an amorphous oxide semiconductor layer containing any element of indium, gallium, zinc, and tin is used. A film may be formed.

  Next, by forming a protective film and patterning the protective film, a channel protective film 106 ′ is formed on the metal oxide semiconductor layer 106, and a channel protective film 107 ′ is formed on the metal oxide semiconductor layer 107. It is formed. Subsequently, by forming a metal layer and patterning the metal layer, the drain electrode (first electrode) 108 in contact with one end of the metal oxide semiconductor layer 106, the other end of the metal oxide semiconductor layer 106, and A source electrode (second electrode) 109 that contacts one end of the counter electrode 25, a source electrode (first electrode) 110 that contacts one end of the metal oxide semiconductor layer 107, the other end of the metal oxide semiconductor layer 107, and A drain electrode (second electrode) 111 is formed in contact with the other end of the counter electrode 25. Thereafter, the insulating layer 112 is formed, and finally the protective layer 113 is formed.

  As described above, the first voltage is applied to the counter electrode 25 of the desired tactile presentation element, and then both the first thin film transistor 23 and the second thin film transistor 24 are turned off, and charges are accumulated in the counter electrode 25 of the tactile presentation element. In addition, in the state where the counter electrode 25 of the tactile display element other than the desired tactile display element is electrically disconnected from the first voltage supply line L6 and the second voltage supply line L7, the counter electrode 25 of the tactile display element and the body of the user When a capacitive coupling is formed with the part (mainly the finger) 114, a charge having a polarity opposite to that accumulated in the counter electrode 25 of the tactile presentation element is induced under the skin of the user's body part. Coulomb force works between charges of different polarities. For this reason, the user's body part (mainly the finger) 114 moves, and electrostatic force is generated and the stimulation is transmitted to the receptor under the skin, and the user has a different texture even though the smooth surface is flicked. I can feel a sense.

FIG. 6 is a diagram illustrating an example of gate voltage-drain current characteristics of the first thin film transistor 23 and the second thin film transistor 24. In the example shown in FIG. 6, the gate length is 2.5 μm, the gate width is 50 μm, and the drain voltage is 10V. The drain current in the off state was a value smaller than the measurement limit of 10 ⁻¹³ A.

  When the counter electrode 25 of the tactile presentation element is electrically separated from the first voltage supply line L6 and the second voltage supply line L7 after the electric charge is accumulated in the counter electrode 25 of the tactile presentation element, the body part of the user Unless the (mainly finger) 114 touches the region corresponding to the counter electrode 25 of the insulating layer 112, there is almost no leakage of the accumulated charge.

  In addition, even when the user's body part (mainly finger) 114 touches the region corresponding to the counter electrode 25 of the insulating layer 112, the fluctuation of the charge is slight. Therefore, even when the user's body part (mainly a finger) 114 is constantly touching the region corresponding to the counter electrode 25 of the insulating layer 112, the necessary amount of charge is transferred to the counter electrode by refreshing at intervals of about several Hz. 25.

Second Embodiment
The tactile display device according to the second embodiment of the present invention has a configuration in which a charge pump circuit 26 is added to the tactile function panel 2 of the tactile display device according to the first embodiment of the present invention. As shown in FIG. 7, each charge pump circuit 26 is provided between each first thin film transistor 23 and the counter electrode 25 of the tactile sense presentation element.

  A configuration example of the charge pump circuit 26 is shown in FIG. The charge pump circuit shown in FIG. 8 includes thin film transistors 201 to 205 and capacitors 206 to 209 connected in series, and an output voltage obtained by boosting the first voltage V1 supplied from the first thin film transistor 23 (see FIG. 7). Vout can be output. A clock signal CLK is supplied from the Y-direction multiplexer circuit 22 (see FIG. 7) to each gate electrode of the thin film transistors 202 and 204, and inverted from the Y-direction multiplexer circuit 22 (see FIG. 7) to each gate electrode of the thin film transistors 203 and 205. A clock signal bar CLK is supplied. A buffer (not shown) is preferably provided between each gate electrode of the thin film transistors 202 and 204 and the Y-direction multiplexer circuit 22 (see FIG. 7). Similarly, it is preferable to provide a buffer (not shown) between the gate electrodes of the thin film transistors 203 and 205 and the Y-direction multiplexer circuit 22 (see FIG. 7).

  Since the first voltage normally needs to be about 50V to 100V, when the size of the haptic function panel 2 is increased, the length of the wiring portion between the Y-direction multiplexer circuit 22 and the counter electrode 25 of each haptic display element is reduced. It varies greatly depending on the position of the tactile sensation presenting element, and variation due to the load on the wiring portion of the voltage applied to the counter electrode 25 of each tactile sensation presenting element cannot be ignored.

  In the present embodiment, since the applied voltage can be adjusted for each counter electrode 25 of the tactile presentation element by the charge pump circuit 26, the above-described variation can be suppressed. Note that the Y-direction multiplexer circuit 22 has a built-in data table that indicates the relationship between the position of the counter electrode 25 of each tactile presentation element and the boost amount of each charge pump circuit 26 corresponding to the counter electrode 25 of each tactile presentation element. What is necessary is just to memorize | store in a memory and to control each charge pump circuit 26 based on the said data table.

  In order to reduce power consumption, the thin film transistor that is a component of the charge pump circuit 26 is also preferably a thin film transistor using a metal oxide semiconductor, like the first thin film transistor 23 and the second thin film transistor 24.

<Third Embodiment>
The tactile display device according to the third embodiment of the present invention has the same configuration as the tactile display device according to the first embodiment of the present invention, but the operation of the tactile function panel 2 is different.

  A first voltage is applied to the counter electrode 25 of the desired tactile presentation element, and then both the first thin film transistor 23 and the second thin film transistor 24 are turned off, charge is accumulated in the counter electrode 25 of the tactile presentation element, and the desired tactile sense A state in which the counter electrode 25 of the tactile presentation element around the presentation element is electrically disconnected from the first voltage supply line L6 and electrically connected to the second voltage supply line L7 and a second voltage (for example, ground voltage) is applied. In FIG. 9, when capacitive coupling is formed between the counter electrode 25 of the tactile presentation element and the body part (mainly finger) 114 of the user, current is used in the direction of the arrow in the figure as shown in FIG. Flows through the body part (mainly fingers) 114 of the person. When the value of this current is set to about several mA, a receptor such as a pachinko body under the skin of the user's body part (mainly finger) 114 can be stimulated by the current. In FIG. 9, the hatched counter electrode 25 is a counter electrode of a desired tactile sense presentation element.

  Note that the tactile display device according to the third embodiment of the present invention is also changed to the tactile display device according to the second embodiment of the present invention, that is, charged with respect to the tactile display device according to the first embodiment of the present invention. Additional pumps can be made.

<Modification>
Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in each embodiment described above, a liquid crystal element is used as the display element, but other display elements may be used. For example, an organic EL element having a structure in which an organic thin film is sandwiched between an anode and a cathode can be used.

  Further, an upper electrode may be provided between the insulating layer 112 and the protective layer 113 in a region corresponding to the counter electrode 25 of the tactile sense presentation element. In this case, in order to reduce the contact resistance between the upper electrode and the body part 114 of the user, the insulating layer 112 may be removed only in a region corresponding to the counter electrode 25 of the tactile sense presentation element.

A touch panel may be provided between the over-type liquid crystal display panel 1 and the tactile function panel 2. The touch detection method of the touch panel is not particularly limited, but a contact detection method capable of detecting contact even if the tactile function panel 2 is provided on the upper portion may be adopted.

DESCRIPTION OF SYMBOLS 1 Over liquid crystal display panel 2 Tactile function panel 3 Protective layer 4 Transmission circuit for transmission type liquid crystal display panel 5 Drive circuit for tactile function panel 11 Signal electrode drive circuit 12 Scan electrode drive circuit 13 Thin film transistor 14 Liquid crystal element 15 Additional capacity 16 Common electrode 21 X-direction multiplexer circuit 22 Y-direction multiplexer circuit 23 First thin film transistor 24 Second thin film transistor 25 Counter electrode of tactile sensation display element 26 Charge pump circuit 101 Translucent insulating substrate 102, 103 Gate electrode 104, 105 Gate insulating layer 106, 107 Metal Oxide semiconductor layer 106 ', 107' Channel protective film 108, 111 Drain electrode 109, 110 Source electrode 112 Insulating layer 113 Protective layer 114 User body part L1 Signal line L2 Scan line L3 Common line L4 First control line L5 Second control line L6 First voltage supply line L7 Second voltage supply line

Claims (5)

A tactile presentation element that presents a tactile sense by electrical stimulation;
A drive unit for driving the tactile sense presentation element,
The tactile sensation providing apparatus, wherein the driving unit includes a thin film transistor using a metal oxide semiconductor containing indium, gallium, zinc, and oxygen as main components. The tactile presentation element includes an electrode and an insulator provided on the electrode,
Static electricity generated between the charge accumulated on the electrode and the charge charged on the user's part when a capacitive coupling through the insulator is formed between the electrode and the user's body part The tactile sensation providing apparatus according to claim 1, wherein a tactile sensation is presented to the body part of the user by force. A plurality of the tactile sense presenting elements are provided,
The drive unit includes a plurality of charge pump circuits including at least one capacitor and at least one transistor,
The tactile sense presentation device according to claim 1, wherein the tactile sense presentation element and the charge pump circuit have a one-to-one correspondence. A display unit having a plurality of pixels;
A tactile display device comprising the tactile sense presenting device according to claim 1.   The tactile display device according to claim 4, wherein the pixel includes a liquid crystal element or an organic EL element.