JP2012108402A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve tactile feedback while saving space and energy.SOLUTION: A support plate 108 is fixed to a substrate 104, and a display 106 is fixed to the support plate 108. A pass hole 110 is provided between the support plate 108 and the substrate 104. An electrostrictive actuator 116 that comprises shim board 112 and piezoelectric body 114 is installed in a backside of the support plate 108. A part of the shim board 112 is taken out to the face side of the display 106 through the pass hole 110 and is bent. A transparent panel 118 is pasted to a bent portion 122 of the shim board 112.

Description

  The present invention relates to an image display device, and more particularly to an image display device having a haptic feedback function.

  There are many electronic devices equipped with a touch panel such as a portable information terminal, a digital camera, an automated teller machine (ATM), and a car navigation system. Since the touch panel has a thickness of about several millimeters, it is suitable for downsizing electronic devices. In addition, since the input interface can be defined by software, there is an advantage that various inputs can be realized in a limited space.

  When the mechanical button is pressed, the repulsive force from the button is transmitted, so that the user can be sure of accepting the input by touch. However, the touch panel has no stroke feeling. Various techniques have been proposed as techniques for artificially creating a tactile sensation.

JP 2006-165318 A JP 2005-222326 A JP 2010-152889 A

  Among them, a tactile sensation generating method using a piezoelectric actuator is widely used. Since the piezoelectric actuator vibrates by an alternating voltage, an artificial tactile sensation can be generated by an electrical signal. Since the piezoelectric actuator can be realized with a thickness of 1 mm or less, it is desirable from the viewpoint of miniaturization of electronic equipment. In Patent Document 1 and Patent Document 2, a piezoelectric actuator is disposed in the peripheral portion of the display. However, in the case of such an arrangement method, an area for the piezoelectric actuator must be secured around the display.

  On the other hand, in Patent Document 3, a piezoelectric actuator is installed on the back of the display to vibrate the display itself. Since the area for the piezoelectric actuator is unnecessary around the display, it becomes easy to use a display as large as possible in a limited space. However, in order to vibrate the display itself, a relatively strong piezoelectric actuator is required. As a result, the cost and power consumption of the piezoelectric actuator are likely to increase. In addition, the vibration of the display itself may induce a display failure.

  The present invention has been completed in view of the above problems, and a main object thereof is to provide an image display device capable of realizing tactile feedback while saving space and energy.

  An image display device according to the present invention includes a display, a transparent panel that covers the display, and a piezoelectric actuator that is connected to the transparent panel and vibrates the transparent panel. The transparent panel and the piezoelectric actuator are connected via a connecting member. Since the piezoelectric actuator uses a transparent panel as a vibration control target instead of a display, the burden on the piezoelectric actuator is reduced. The piezoelectric actuator and the display are not fixedly connected.

  The image display device includes a support plate that fixes the display to the surface. The piezoelectric body of the piezoelectric actuator is installed on the back side of the support plate. By installing the piezoelectric body on the back surface of the support plate, in other words, on the back surface side of the display, it becomes easy to adopt a display as large as possible in a limited space.

  One end of the connecting member is bent substantially in parallel with the display, and the transparent panel is fixed on the bent end. By using the connecting member having such a substantially planar configuration, vibration is easily transmitted to the planar transparent panel.

  The transparent panel may be formed as a touch panel. And a control circuit may drive a piezoelectric actuator on the occasion of contact with a transparent panel.

  According to the present invention, tactile feedback can be easily realized while saving space and energy.

It is a sectional side view of an image display device. It is a disassembled perspective view of an image display device. It is a top view which shows the relationship between a support plate and a board | substrate. It is a top view which shows a state when passing a shim board. It is a schematic diagram which shows the vibration state at the time of the shrinkage | contraction of a piezoelectric material. It is a schematic diagram which shows the vibration state at the time of expansion | extension of a piezoelectric material.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a side sectional view of the image display device 100. The image display device 100 here may be an electronic device having an image display function, such as a portable information terminal, a car navigation system, and a TV. The image display device 100 in the present embodiment will be described as a portable information terminal.

  The x axis is set in the right direction, the z axis is set in the upward direction, and the y axis is set in the vertical direction on the drawing. Unless otherwise specified, the thickness direction means the z-axis direction. A storage area 102 is formed on the substrate 104 of the image display device 100. The storage area 102 is an area for storing the display 106, the support plate 108, and the like. The display 106 in the present embodiment is an LCD (Liquid Crystal Display). The display 106 may be formed as a thin display by other methods such as organic EL (Organic Electro-Luminescence).

  The support plate 108 is fixed to the substrate 104, and the display 106 is fixed to the support plate 108. Although details will be described later with reference to FIGS. 2 to 4, a metal shim plate 112 (connection member) is passed through the passage hole 110 between the support plate 108 and the substrate 104. The shim plate 112 is formed as a stainless steel plate having a thickness of about 100 to 500 μm. A piezoelectric body 114 is fixed to one end of the shim plate 112. A “piezoelectric actuator 116” is formed by the shim plate 112 and the piezoelectric body 114. A sufficiently long shim plate 112 is used so that the shim plate 112 to which the piezoelectric body 114 is attached can be connected to the transparent panel 118. Alternatively, one shim plate 112 may be assembled from a plurality of parts in consideration of workability during assembly.

  The piezoelectric body 114 is formed of zircon / lead titanate (PZT), barium titanate, lithium niobate, or the like. The shim plate 112 is set to the ground potential. The piezoelectric body 114 can be vibrated by applying an alternating voltage to the conductive shim plate 112. The piezoelectric actuator 116 has a bimorph structure or a unimorph structure. The piezoelectric actuator 116 in the present embodiment will be described on the assumption that a displacement of several μm to several 100 μm can be obtained with a voltage of 300 (V) or less.

  The piezoelectric actuator 116 is connected to the control circuit 120. The control circuit 120 vibrates the piezoelectric actuator 116 by supplying an AC voltage to the piezoelectric actuator 116. Specific modes of vibration will be described later with reference to FIGS.

  A portion of the shim plate 112 extends in the positive z-axis direction from the passage hole 110 and is then bent so as to be substantially parallel to the surface (xy plane) of the display 106. A transparent panel 118 is affixed on the bent portion 122. In this embodiment, the transparent panel 118 is a touch panel, and the control circuit 120 is also connected to the transparent panel 118. When detecting the user's contact with the transparent panel 118, the control circuit 120 drives the piezoelectric actuator 116 to vibrate the transparent panel 118. This mechanism realizes tactile feedback.

  FIG. 2 is an exploded perspective view of the image display device 100. The rectangular support plate 108 has a protrusion 124 at the center of each of the four sides. A display 106 is affixed on the support plate 108. Below the support plate 108, four piezoelectric actuators 116a to 116d are installed. Each piezoelectric actuator 116 extends from the side of the support plate 108 in the positive z-axis direction. Then, the bent portion 122 of the piezoelectric actuator 116 is bonded to the transparent panel 118. In summary, the display 106 and the support plate 108 are fixed to become the first part, and the piezoelectric actuators 116a to 116d and the transparent panel 118 are also fixed to become the second part. The first part and the second part are not fixed to each other. The first part is fixed to the substrate 104. Since the bent portion 122 and the display 106 are substantially parallel, the display 106 and the transparent panel 118 are also substantially parallel.

  FIG. 3 is a plan view showing the relationship between the support plate 108 and the substrate 104. The substrate 104 is provided with a storage region 102 in the thickness direction. A support plate 108 is placed on the storage area 102. The support plate 108 is fixed to the substrate 104 by the four protrusions 124 of the support plate 108. Further, there are gaps at the four corners of the substrate 104. This becomes the passage hole 110. The shim plate 112 protrudes from the back surface of the support plate 108 to the front surface through the passage hole 110. FIG. 4 is a plan view showing a state when the shim plate 112 is passed. Next, the vibration mode of the piezoelectric actuator 116 will be described.

  FIG. 5 and FIG. 6 are schematic diagrams showing vibration modes of the piezoelectric actuator 116. The piezoelectric body 114 vibrates in the d31 mode. When an AC voltage is supplied to the piezoelectric body 114, the piezoelectric body 114 contracts in the plane direction. FIG. 5 shows a state when the piezoelectric body 114 contracts. When the piezoelectric body 114 contracts, the shim plate 112 is deformed in a rising direction with respect to the substrate 104, so that the bent portion 122 connected to the transparent film 118 is directed inward. The transparent panel 118 rises in the positive z-axis direction. FIG. 6 shows a state when the piezoelectric body 114 is expanded. When the piezoelectric body 114 expands, the bent portion 122 moves outward, so that the transparent panel 118 is pushed in the negative z-axis direction.

  When the control circuit 120 supplies an AC voltage to the piezoelectric body 114, the operations described in relation to FIGS. 5 and 6 are repeated. By supplying an alternating voltage when the user touches the transparent panel 118, a tactile sensation can be given to the user.

  The image display device 100 has been described based on the embodiments. In the image display device 100, the piezoelectric body 114 is installed not on the side of the display 106 but on the back. For this reason, it becomes easy to use a display as large as possible in a limited space. Further, instead of vibrating the display 106 as in Patent Document 3, the transparent panel 118 on the display 106 is vibrated. The display 106 and the transparent panel 118 are not fixedly connected. Since the transparent panel 118 is less rigid than the display 106, the transparent panel 118 can be vibrated efficiently even with the piezoelectric actuator 116 having a small power. In other words, one thin skin called the transparent panel 118 is the object of vibration control. As a result, tactile feedback can be generated with reduced space and energy. Even if a strong impact is applied from the surface of the transparent panel 118, the transparent panel 118 and the piezoelectric body 114 are indirectly connected through the shim plate 112 and the bent portion 122. Absorbed by springiness. Further, since a space in which the piezoelectric actuator 116 can operate is secured in the storage area 102, the piezoelectric body 114 itself has a structure that is not directly sandwiched between members such as the transparent film 118, the display, and the substrate 104. Since no direct impact is applied to the piezoelectric body 114, it is easy to prevent damage.

  The present invention has been described based on the embodiments. It will be understood by those skilled in the art that the embodiments are illustrative, and that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. By the way. Accordingly, the description and drawings herein are to be regarded as illustrative rather than restrictive.

  100 image display device, 102 storage area, 104 substrate, 106 display, 108 support plate, 110 passage hole, 112 shim plate, 114 piezoelectric body, 116 piezoelectric actuator, 118 transparent panel, 120 control circuit, 122 bent portion, 124 protrusion .

Claims (6)

Display,
A transparent panel covering the display;
A piezoelectric actuator coupled to the transparent panel to vibrate the transparent panel;
An image display device comprising:   The image display device according to claim 1, wherein the piezoelectric actuator and the display are not fixedly connected. A support plate for fixing the display to the surface;
The piezoelectric body of the piezoelectric actuator is installed on the back surface side of the support plate, and transmits the vibration to the transparent panel by being connected to the transparent panel on the front surface side of the support plate via a connecting member. The image display device according to claim 1 or 2.   The image display device according to claim 3, wherein one end of the connecting member is bent substantially in parallel with the display, and the transparent panel is fixed on the bent end. The transparent panel is formed as a touch panel,
The image display device according to claim 1, further comprising a control circuit that drives the piezoelectric actuator in response to contact with the transparent panel.   The image display device according to claim 1, wherein the piezoelectric actuator is stored in a storage area provided on a substrate.

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