# Patent

## Title
Touch panel vibrator with reduced visibility

## Abstract

An electronic device includes a touch panel having a first principal surface and a second principal surface positioned opposite to the first principal surface; a light shielding film formed on the first principal surface of the touch panel corresponding to a non-operation area; and a vibrator provided on the second principal surface of the touch panel corresponding to the non-operation area. When a critical angle where light is totally reflected by the second principal surface of the touch panel is represented by θ and sum of a thickness T1 of the touch panel and a thickness T2 of the vibrator is represented by T, the vibrator is provided, on the second principal surface of the touch panel corresponding to the non-operation area, at a position apart by T×tan θ or more from an end of the light shielding film which end is positioned on the operation area side, in sectional view.

## Background
FIELD OF INVENTION
The present invention relates to an electronic device and a mobile terminal including the same.
BACKGROUND
In recent years, there is known a tactile transmission technique to transmit various tactile senses such as a sense of pressing, a sense of tracing, or a sense of texture to a user when the user operates a touch panel in an electronic device including a touch panel (for example, see Patent Literature 1).
An electronic device to which such a tactile transmission technique is applied includes a display panel; a touch panel disposed to be opposed to the display panel with a space interposed therebetween; a vibrator provided on a rear surface of the touch panel; and a base that supports the touch panel. The electronic device can transmit various tactile senses to the user by causing flexural vibration of the touch panel according to expansion and contraction motions of the vibrator.
In the electronic device described above, however, the touch panel is disposed to be opposed to the display panel with a space interposed therebetween. Accordingly, when a user looks into the electronic device from an oblique direction, for example, there is a possibility that the vibrator provided on the rear surface of the touch panel is visually observed by the user.
CITATION LIST
Patent Literature


    Patent Literature 1: Japanese Laid-open Patent Publication No. 2003-122507.


SUMMARY
Technical Problem
The present invention has been made in view of the above-mentioned problem, and it is an object of the present invention to provide an electronic device capable of reducing a possibility that a vibrator is visually observed by a user, and a mobile terminal including the electronic device.
An aspect of an electronic device according to the present invention is an electronic device including an operation area and a non-operation area positioned outside the operation area, the electronic device including: an operation unit including a first principal surface and a second principal surface positioned opposite to the first principal surface; a light shielding film formed on the first principal surface of the operation unit corresponding to the non-operation area; and a vibrator provided on the second principal surface of the operation unit corresponding to the non-operation area, wherein when a critical angle at which light is totally reflected by the second principal surface of the operation unit is represented by θ and sum of a thickness T1 of the operation unit and a thickness T2 of the vibrator is represented by T, the vibrator is provided, on the second principal surface of the operation unit corresponding to the non-operation area, at a position apart by T×tan θ or more from an end of the light shielding film which end is positioned on the operation area side, in sectional view.
According to an aspect of a mobile terminal according to the present invention, the electronic device according to the present invention is provided in a housing.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view illustrating a schematic configuration of an electronic device according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along a cutting-plane line I-I illustrated in FIG. 1.
FIG. 3 is a sectional view taken along a cutting-plane line II-II illustrated in FIG. 1.
FIG. 4 is an enlarged view of a portion A1 illustrated in FIG. 3.
FIG. 5 is a flowchart illustrating an operation example of the electronic device.
FIG. 6 is a perspective view illustrating a schematic configuration of a mobile terminal.
FIG. 7 is a plan view illustrating a schematic configuration of an electronic device according to a second embodiment of the present invention.
FIG. 8 is a schematic view taken along a cutting-plane line III-III illustrated in FIG. 7.
FIG. 9 is a sectional view taken along a cutting-plane line IV-IV illustrated in FIG. 7.
FIG. 10 is an enlarged view of a portion A2 illustrated in FIG. 9.
FIG. 11 is a plan view illustrating a schematic configuration of an electronic device according to a third embodiment of the present invention.
FIG. 12 is a sectional view taken along a cutting-plane line V-V illustrated in FIG. 11.
FIG. 13 is an enlarged view of a portion A3 illustrated in FIG. 12.
FIG. 14 is a plan view illustrating a schematic configuration of an electronic device according to a fourth embodiment of the present invention.
FIG. 15 is a sectional view taken along a cutting-plane line VI-VI illustrated in FIG. 14.
FIG. 16 is an enlarged view of a portion A4 illustrated in FIG. 15.
FIG. 17 is a plan view illustrating a schematic configuration of an electronic device according to a fifth embodiment of the present invention.
FIG. 18 is a sectional view taken along a cutting-plane line VII-VII illustrated in FIG. 17.
FIG. 19 is a sectional view taken along a cutting-plane line VIII-VIII illustrated in FIG. 17.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that in the drawings to be referred to hereinafter, primary members necessary to describe the present invention, among components according to an embodiment of the present invention, are illustrated in a simplified manner, for convenience of explanation. Accordingly, an electronic device according to the present invention and a mobile terminal including the same may include other components that are not illustrated in the drawings to be referred to herein.
First Embodiment
As illustrated in FIGS. 1 to 3, an electronic device X1 according to this embodiment includes an operation area E0 and a non-operation area E1 which is located outside the operation area E0. The operation area E0 is an area in which a user can perform an input operation. The non-operation area E1 is an area in which a user cannot perform an input operation.
The electronic device X1 includes a liquid crystal panel 2, a touch panel 3, a vibrator 4, a light shielding film 5, a base substance 6, a frame body 7, and bases 8.
The liquid crystal panel 2 is a display panel using a liquid crystal composition for display. Specifically, the liquid crystal panel 2 includes one substrate; the other substrate disposed to be opposed to the one substrate; a liquid crystal layer interposed between the one substrate and the other substrate; a display member layer that is interposed between the one substrate and the other substrate and contributes to display; and a backlight that irradiates light to the one substrate and the other substrate. Herein, for convenience of explanation, illustration of each of the one substrate, the other substrate, the liquid crystal layer, the display member layer, and the backlight is herein omitted. Note that examples of the display member layer include a pixel electrode, an alignment film, and a color filter. As a drive system of the liquid crystal panel 2, a simple matrix drive system or an active matrix drive system may be employed.
Note that a display panel, such as a plasma panel, an organic EL panel, or electronic paper, may be used instead of the liquid crystal panel 2. The organic EL panel is a display panel incorporating a substance that emits light upon application of a voltage. Specifically, the organic EL panel performs display by depositing a luminous body using an organic substance, such as diamines, onto a substrate and applying a DC voltage of 5 to 10 V. In a case of using the organic EL panel instead of the liquid crystal panel 2, there is no need to provide a backlight.
The touch panel (operation unit) 3 is an input device that detects a location where a user operates with a finger, a pen, or the like, as an input position. The touch panel 3 has a first principal surface 3a and a second principal surface 3b positioned opposite to the first principal surface 3a. In other words, the first principal surface 3a of the touch panel 3 corresponding to the operation area E0 serves as a surface on which a user directly operates with a finger, a pen, or the like. As illustrated in FIGS. 2 and 3, the touch panel 3 is disposed to be opposed to the liquid crystal panel 2 with a space 51 interposed therebetween. As illustrated in FIG. 1, the touch panel 3 has a rectangular shape in plane view. However, a shape of the touch panel 3 is not limited thereto, and any shape may be used.
In this embodiment, a capacitive touch panel is used as the touch panel 3 in terms of improvement in detection sensitivity. Alternatively, a resistive touch panel, a surface acoustic wave touch panel, an infrared touch panel, an electromagnetic induction type touch panel, or the like may be used instead of the capacitive touch panel. In this embodiment, the touch panel 3, which is a capacitive touch panel, includes a base substance; a detection electrode that is provided on the base substance and detects an input position; and a detection electrode wiring that is provided on the base substance and electrically connected to the detection electrode. Examples of material of the base substance include glass, plastic, and acryl.
Herein, the touch panel 3 may be in a state of including a protective member to protect the touch panel 3, or may be in a state of including no protective member. When the touch panel 3 is in the state of including the protective member, the first principal surface 3a of the touch panel 3 may mean an upper surface of the protective member, or may mean an upper surface of the base substance forming the touch panel 3 in the state of including no protective member. The second principal surface 3b of the touch panel 3 may mean a lower surface of the base substance forming the touch panel 3, or may mean a lower surface of an insulating film formed on the lower surface of the base substance forming the touch panel 3.
When the touch panel 3 is a resistive touch panel including an upper substrate; a first resistance film formed on the upper substrate; a lower substrate disposed to be opposed to the upper substrate; and a second resistance film formed on the lower substrate, the first principal surface 3a of the touch panel 3 means an upper surface of the upper substrate. The second principal surface 3b of the touch panel 3 means a lower surface of the lower substrate. The term “operation unit” herein described may mean only the lower substrate of the resistive touch panel. In this case, the term “the first principal surface of the operation unit” means an upper surface of the lower substrate, and the term “the second principal surface of the operation unit” means a lower surface of the lower substrate.
The vibrator 4 is a member that serves to cause flexural vibration of the touch panel 3, upon detecting a predetermined input operation by a user. Specifically, the vibrator 4 repeats expansion and contraction motions in a short-side direction of the touch panel 3 (a left and right direction in FIG. 1), thereby causing flexural vibration of the touch panel 3 in a thickness direction of the touch panel 3 (this direction is hereinafter referred to as a “vertical direction”). Note that as described in detail later, the vibrator 4 also serves to detect a pressing load onto the touch panel 3. The vibrator 4 is provided on the second principal surface 3b of the touch panel 3 corresponding to the non-operation area E1, with an adhesive member, which is not illustrated, interposed therebetween. In this embodiment, the vibrator 4 is a piezoelectric element that performs expansion and contraction motions based on an applied voltage, for example, but a configuration of the vibrator 4 is not limited thereto. An electromagnetic vibrator, a spring, a motor, or the like may be used instead of the piezoelectric element.
In this embodiment, the vibrator 4, which is a piezoelectric element, has a following configuration. That is, the vibrator 4 has a substantially rectangular parallel-piped shape, and has a configuration in which an electrode and an active layer are alternately stacked and an inert layer is formed on an active layer positioned near the second principal surface 3b of the touch panel 3. Herein, the active layer is made of a polarized piezoelectric material. The inert layer is formed of a non-polarized piezoelectric material, a metallic material, or an insulating material.
In this embodiment, as illustrated in FIG. 1, the vibrator 4 consists of two vibrators that are respectively provided along both short sides of the touch panel 3 and in the vicinity of the both short sides. Note that a layout position, number, and the like of the vibrator 4 are not particularly limited. For example, the vibrator 4 may consist of two vibrators that are respectively provided along both long sides of the touch panel 3 and in the vicinity of the both long sides, or four vibrators that are respectively provided along the long sides and the short sides of the touch panel 3 and in the vicinity of the both long sides and the both short sides.
The light shielding film 5 is a member having a light shielding property to shield light. The light shielding film 5 is formed by printing black pigment on the first principal surface 3a of the touch panel 3, for example. Instead of this, tape having a light shielding property may be used as the light shielding film 5. The light shielding film 5 is provided on the first principal surface 3a of the touch panel 3 corresponding to the non-operation area E1. In this embodiment, as illustrated in FIG. 1, the light shielding film 5 is provided in a frame shape so as to surround the liquid crystal panel 2 in plan view.
A layout position of the vibrator 4 relative to the light shielding film 5 will now be described. FIG. 4 is an enlarged view of a portion A1 illustrated in FIG. 3. First, as illustrated in FIG. 4, assume that a critical angle at which light is totally reflected by the second principal surface 3b of the touch panel 3 is represented by θ and the sum of a thickness T1 of the touch panel 3 and a thickness T2 of the vibrator 4 is represented by T. Note that this total reflection means that incident all light is reflected without passing through an interface when light enters a medium having a small refractive index from a medium having a large refractive index. The total reflection occurs when an angle of incidence is a certain angle (critical angle) or more. In this embodiment, a base substance of the touch panel 3 is glass, plastic, or acryl. Accordingly, the total reflection occurs at the second principal surface 3b of the touch panel 3 when an angle of incidence is a critical angle of θ or more. This is because a refractive index of air is about 1, whereas a refractive index of glass is about 1.5 to 1.9; a refractive index of plastic is about 1.5 to 1.7; and a refractive index of acryl is about 1.4 to 1.5. The critical angle θ of glass is about 42° and the critical angle θ of acryl is also about 42°.
Specifically, if assuming that L1 in FIG. 4 represents a visual line direction (incident light) of a user, when the visual line direction L1 of the user corresponds to being equal to or greater than the critical angle θ, total reflection occurs at the second principal surface 3b of the touch panel 3. This makes it difficult to visually observe the vibrator 4 provided on the second principal surface 3b of the touch panel 3. On the other hand, when the visual line direction L1 of the user is less than the critical angle θ, the vibrator 4 provided on the second principal surface 3b of the touch panel 3 is visually observed due to its layout position. That is, when the visual line direction L1 of the user is less than the critical angle θ, it is important to devise a layout position of the vibrator 4 so as to prevent the vibrator 4 from being visually observed.
Accordingly, in the electronic device X1, the vibrator 4 is provided, on the second principal surface 3b of the touch panel 3 corresponding to the non-operation area E1, at a position apart by T×tan θ or more from an end 51 of the light shielding film 5 which end 51 is positioned on the operation area E0 side, in sectional view. Thus, even if the visual line direction L1 of the user corresponds to being less than the critical angle θ, because the vibrator 4 is not located within a range in which a user can look into the second principal surface 3b of the touch panel 3 with the visual line direction corresponding to being less than the critical angle θ, a possibility that the vibrator 4 is visually observed by a user can be reduced.
Each of the base substance 6 and the frame body 7 is a member that serves to house the liquid crystal panel 2. The base substance 6 has a third principal surface 6a. The liquid crystal panel 2 is provided on or above the third principal surface 6a of the base substance 6. As illustrated in FIG. 1, the frame body 7 is provided on the third principal surface 6a of the base substance 6 so as to surround the liquid crystal panel 2 in plan view. Examples of material of the base substance 6 and the frame body 7 include resin such as polycarbonate and metal such as stainless, aluminum, or magnesium alloy. The base substance 6 and the frame body 7 may be integrally formed, or may be separately formed.
The base 8 is a member that serves to support the touch panel 3 at the non-operation area E1. The base 8 is provided on the third principal surface 6a of the base substance 6. In this embodiment, the base 8 consists of bases that are located at six positions in total, i.e., at four corners C1 to C4 of the touch panel 3, at a location between the corners C1 and C2, and at a location between the corners C3 and C4. A shape of the base 8 is a cylindrical shape, for example, but may be a rectangular columnar shape or the like. Examples of material of the base 8 include silicone rubber, urethane rubber, urethane foam, other rubbers, and plastic.
Next, an operation example of the electronic device X1 will be described with reference to FIG. 5.
Note that an operation example of the electronic device X1 when a sense of pressing is transmitted to a user as tactile transmission will be described below. However, the electronic device X1 is applicable to a case where various tactile senses, such as a sense of tracing or texture feeling, in addition to the sense of pressing are transmitted.
As illustrated in FIG. 5, when a user presses the first principal surface 3a of the touch panel 3, the vibrator 4 detects a pressing load onto the touch panel 3 (Op1). A load detection function of the vibrator 4 will now be described. That is, when a user presses the first principal surface 3a of the touch panel 3, the touch panel 3 is curved downward. When the touch panel 3 is curved downward, the vibrator 4 is also curved downward. In other words, amount of curvature of the vibrator 4 varies depending on a pressing load onto the first principal surface 3a of the touch panel 3. In this embodiment, since the vibrator 4 is a piezoelectric element, the vibrator 4 can perform conversion to a voltage depending on the amount of curvature. As a result, the vibrator 4 can detect the pressing load onto the touch panel 3. Note that an example in which the load detection function is implemented by the vibrator 4 has been described above, but the present invention is not limited thereto. The load detection function may be implemented by a load sensor such as a distortion sensor.
Then, when an input operation by a user is a pressing operation on an input object displayed on a display screen, a tactile transmission driver, which is not illustrated, determines whether the pressing load detected in Op1 is equal to or greater than a threshold (Op2). Note that the tactile transmission driver is provided on an FPC (Flexible Printed Circuit) connected to the touch panel 3, together with a touch panel driver that controls the touch panel 3, for example.
When determining that the pressing load detected in Op1 is equal to or greater than the threshold (YES in Op2), the tactile transmission driver causes the vibrator 4 to make expansion and contraction motions in the short-side direction of the touch panel 3 (Op3). Then, the vibrator 4, which are caused to make expansion and contraction motions in Op3, causes flexural vibration of the touch panel 3 in the vertical direction (Op4). As a result, a sense of pressing is transmitted to a user having pressed the first principal surface 3a of the touch panel 3. On the other hand, when determining that the pressing load detected in Op1 is less than the threshold (NO in Op2), the tactile transmission driver completes processing illustrated in FIG. 5.
From the above, the electronic device X1 described above can reduce a possibility that the vibrator 4 is visually observed by a user.
Next, a mobile terminal Y1 including the electronic device X1 will be described with reference to FIG. 6.
As illustrated in FIG. 6, the mobile terminal Y1 is, for example, a cellular phone, a smartphone, or a PDA, and includes the electronic device X1 described above, a voice input unit 101, a voice output unit 102, a key input unit 103, and a housing 104.
The voice input unit 101 is composed of a microphone or the like, and receives voice of a user or the like. The voice output unit 102 is composed of a speaker or the like, and outputs voice or the like received from a counterpart. The key input unit 103 is composed of a mechanical key, for example. Note that the key input unit 103 may be an operation key displayed on a display screen. The housing 104 is a member that serves to house the electronic device X1, the voice input unit 101, the voice output unit 102, and the key input unit 103.
In addition, the mobile terminal Y1 may include a digital camera function unit, a tuner for one-segment broadcasting, a short-distance wireless communication unit, such as an infrared communication function unit, and various interfaces, depending on a required function. However, detailed illustration and explanation thereof are omitted.
The mobile terminal Y1 includes the electronic device X1, which contributes to a reduction of a possibility that the vibrator 4 is visually observed by a user.
Note that an example in which the mobile terminal Y1 includes the voice input unit 101 has been described above, but the present invention is not limited thereto. That is, the mobile terminal Y1 does not necessarily include the voice input unit 101.
Second Embodiment
FIG. 7 is a plan view illustrating a schematic configuration of an electronic device X2 according to this embodiment. FIG. 8 is a sectional view taken along a cutting-plane line III-III illustrated in FIG. 7. FIG. 9 is a sectional view taken along a cutting-plane line IV-IV illustrated in FIG. 7. FIG. 10 is an enlarged view of a portion A2 illustrated in FIG. 9. Note that in FIGS. 7 to 10, components having the same functions as those illustrated in FIGS. 1 to 4 are denoted by the same reference numerals, and the detailed explanation thereof is omitted.
As illustrated in FIGS. 7 to 10, the electronic device X2 differs from the electronic device X1, in which a light shielding film 51 is provided on the first principal surface 3a of the touch panel 3, in that the light shielding film 51 is provided on the second principal surface 3b of the touch panel 3 corresponding to the non-operation area E1. Accordingly, in the electronic device X2, a vibrator 41 is provided on the light shielding film 51.
A layout position of the vibrator 41 relative to the light shielding film 51 will now be described. As illustrated in FIG. 10, assume that a critical angle at which light is totally reflected by the second principal surface 3b of the touch panel 3 is represented by θ and a thickness of the vibrator 41 is represented by T2.
If assuming that L1 in FIG. 10 represents a visual line direction (incident light) of a user, when the visual line direction L1 of the user corresponds to being equal to or greater than the critical angle θ, total reflection occurs at the second principal surface 3b of the touch panel 3. This makes it difficult to visually observe the vibrator 41 provided on the light shielding film 51. On the other hand, when the visual line direction L1 of the user corresponding to being less than the critical angle θ, the vibrator 41 provided on the light shielding film 51 is visually observed due to its layout position. That is, when the visual line direction L1 of the user corresponds to being less than the critical angle θ, it is important to devise a layout position of the vibrator 41 so as to prevent the vibrator 41 from being visually observed.
Accordingly, in the electronic device X2, the vibrator 41 is provided, on the light shielding film 51, at a position apart by T2×tan θ or more from an end 511 of the light shielding film 51 which end 511 is positioned on the operation area E0 side, in sectional view. Thus, even if the visual line direction L1 of the user corresponds to being less than the critical angle θ, because the vibrator 41 is not located within a range in which a user can look into the second principal surface 3b of the touch panel 3 with the visual line direction being less than the critical angle θ, a possibility that the vibrator 41 is visually observed by a user can be reduced.
Further, in the electronic device X2, the light shielding film 51 is formed on the second principal surface 3b of the touch panel 3 corresponding to the non-operation area E1, and the vibrator 41 is provided on the light shielding film 51. Accordingly, in the electronic device X2, T2×tan θ can be made smaller than T×tan θ of the electronic device X1. Therefore, in the electronic device X2, the non-operation area E1 can be made smaller than in the electronic device X1. As a result, the electronic device X2 makes it possible to achieve downsizing.
From the above, the electronic device X2 described above can reduce a possibility that the vibrator 41 is visually observed by a user. Further, the electronic device X2 described above makes it possible to achieve downsizing, as compared with the electronic device X1.
Note that the light shielding film 51 described above preferably includes an adhesive member that bonds the vibrator 41 to the second principal surface 3b of the touch panel. Examples of material of the adhesive member include melamine resin, urea resin, phenol resin, vinyl acetate resin, epoxy resin, cyanoacrylate resin, acrylic resin, chloroprene rubber, and styrene butadiene rubber. When the light shielding film 51 includes the adhesive member, it is possible to bond the vibrator 41 to the second principal surface 3b of the touch panel 3 without the need to provide an adhesive member separately from the light shielding film 51. In other words, the vibrator 41 and the second principal surface 3b of the touch panel 3 can be bonded to each other by the light shielding film 51 only through one process of forming the light shielding film 51, without the need to carry out two processes, i.e., a process of forming a light shielding film and a process of forming an adhesive member. That is, the light shielding film 51 preferably includes an adhesive member so as to reduce manufacturing processes.
Third Embodiment
FIG. 11 is a plan view illustrating a schematic configuration of an electronic device X3 according to this embodiment. FIG. 12 is a sectional view taken along a cutting-plane line V-V illustrated in FIG. 11. FIG. 13 is an enlarged view of a portion A3 illustrated in FIG. 12. Note that in FIGS. 11 to 13, components having the same functions as those illustrated in FIGS. 1, 3, and 4 are denoted by the same reference numerals, and the detailed explanation thereof is omitted.
As illustrated in FIGS. 11 to 13, the electronic device X3 differs from the electronic device X1, in which a reflection-reducing film 9 is not formed on a surface 4a of the vibrator 4, in that the reflection-reducing film 9 is formed on the surface 4a of the vibrator 4.
The reflection-reducing film 9 has a reflectance lower than a reflectance of the surface 4a of the vibrator 4. The reflection-reducing film 9 is formed by printing a black pigment on the surface 4a of the vibrator 4, or by coating a black mat paint on the surface 4a of the vibrator 4. Note that the mat paint generates micro-irregularities on a surface of a paint film by adding a matting agent (for example, fine powder silica or polyethylene fine powder) to a paint, and reduces gloss by irregular reflection of light.
Note that in this embodiment, the reflection-reducing film 9 is formed over the whole of the surface 4a of the vibrator 4, but the present invention is not limited thereto. For example, the reflection-reducing film 9 may be formed on a part of the surface 4a of the vibrator 4.
Here, when the visual line direction L1 of the user corresponds to being equal to or greater than the critical angle θ, total reflection occurs at the second principal surface 3b of the touch panel 3. Even when the total reflection occurs, there is a little possibility that the vibrator 4 is visually observed by a user. In this case, if the reflection-reducing film 9 is not formed on the surface 4a of the vibrator 4, reflection of externally incident light by the surface 4a of the vibrator 4 may result in giving a sense of discomfort, such as glare, to the user. On the other hand, in the electronic device X3, the reflection-reducing film 9 is formed on the surface 4a of the vibrator 4, so that the reflection-reducing film 9 suppresses reflection of externally incident light. Therefore, the electronic device X3 can reduce a possibility of giving a sense of discomfort, such as glare, to a user.
From the above, in the electronic device X3 described above, a possibility that the vibrator 41 is visually observed by a user can be reduced. Further, in the electronic device X3 described above, a possibility of giving a sense of discomfort, such as glare, to a user can be reduced.
Fourth Embodiment
FIG. 14 is a plan view illustrating a schematic configuration of an electronic device X4 according to this embodiment. FIG. 15 is a sectional view taken along a cutting-plane line VI-VI illustrated in FIG. 14. FIG. 16 is an enlarged view of a portion A4 illustrated in FIG. 15. Note that in FIGS. 14 to 16, components having the same functions as those illustrated in FIGS. 1, 3, and 4 are denoted by the same reference numerals, and the detailed explanation thereof is omitted.
As illustrated in FIGS. 14 to 16, the electronic device X4 differs from the electronic device X1, in which an inclined portion 421 is not provided to the vibrator 4, in that the inclined portion 421 is provided to a vibrator 42.
The vibrator 42 has a substantially rectangular parallel-piped shape, and has an opposed surface 42a opposed to the second principal surface 3b of the touch panel 3; a rear surface 42b positioned opposite to the opposed surface 42a; and four side surfaces 42c adjacent to the opposed surface 42a and the rear surface 42b. The vibrator 42 has the inclined portion 421 disposed between a side surface 42c′ which is closest to the operation area E0 among the four side surface 42c, and the rear surface 42b. Thus, in the electronic device X4, the vibrator 42 is provided with the inclined portion 421, which reduces a possibility that the vibrator 42 is visually observed by a user, as compared with the electronic device X1.
From the above, the electronic device X4 described above can reduce a possibility that the vibrator 42 is visually observed by a user.
Fifth Embodiment
FIG. 17 is a plan view illustrating a schematic configuration of an electronic device X5 according to this embodiment. FIG. 18 is a sectional view taken along a cutting-plane line VII-VII illustrated in FIG. 17. FIG. 19 is a sectional view taken along a cutting-plane line VIII-VIII illustrated in FIG. 17. In FIGS. 17 to 19, components having the same functions as those illustrated in FIGS. 1 to 3 are denoted by the same reference numerals, and the detailed explanation thereof is omitted.
As illustrated in FIGS. 17 to 19, the electronic device X5 includes a liquid crystal panel 10 having a function of detecting an input position, in place of the liquid crystal panel 2 and the touch panel 3 which are described in the first embodiment.
The liquid crystal panel 10 is disposed to be opposed to the third principal surface 6a of the base substance 6, with the space 51 interposed therebetween. The liquid crystal panel 10 is supported by the base 8, which is provided on the third principal surface 6a of the base substance 6, at the non-operation area E1. The liquid crystal panel 10 has a first principal surface 10a and a second principal surface 10b positioned opposite to the first principal surface 10a. 
The liquid crystal panel 10 includes one substrate; the other substrate disposed to be opposed to the one substrate; a liquid crystal layer interposed between the one substrate and the other substrate; a display member layer that is interposed between the one substrate and the other substrate and contributes to display; and a photodetection unit provided on the one substrate. This photodetection unit corresponds to the function of detecting an input position. When a finger is placed on the liquid crystal panel 10 in a state where external light is incident on a photodetection unit, the external light incident on a photodetection unit positioned corresponding to this finger is blocked. Accordingly, in the liquid crystal panel 10, an input position can be detected through comparison of a detection level of a photodetection unit on which the external light is incident and a detection level of a photodetection unit on which no external light is incident.
Note that an example of the liquid crystal panel including the photodetection unit has been described above as the liquid crystal panel 10 having the function of detecting an input position, but the liquid crystal panel is not limited thereto. For example, a liquid crystal panel in which a detection electrode of a capacitive touch panel is directly formed on the other substrate of the liquid crystal panel 10 may be used as the liquid crystal panel 10 having the function of detecting an input position.
Further, an example of the liquid crystal panel 10 having the function of detecting an input position has been described above, but the present invention is not limited thereto. A display panel, such as a plasma panel, an organic EL panel, or electronic paper having the function of detecting an input position may be used instead of the liquid crystal panel 10.
Furthermore, an example of the mobile terminal Y1 including the electronic device X1 has been described above. However, one of the electronic devices X2 and X5 may be employed instead of the electronic device X1. A mobile terminal including one of the electronic devices X2 to X5 may be employed. The embodiments described above may be combined as needed.
Moreover, an example in which the electronic devices X1 to X5 are applied to the tactile transmission technique have been described above, but the present invention is not limited thereto. The electronic devices X1 to X5 are applicable not only to the tactile transmission technique, but also to a technique of a panel speaker which outputs voice, or a technique that makes it possible to hear sound using bone conduction, for example.
REFERENCE SIGNS LIST


    
    
        X1-X5 ELECTRONIC DEVICE
        Y1 MOBILE TERMINAL
        LIQUID CRYSTAL PANEL (DISPLAY PANEL)
        TOUCH PANEL (OPERATION UNIT)
        4, 41, 42 VIBRATOR
        421 INCLINED PORTION
        5, 51 LIGHT SHIELDING FILM
        6 BASE SUBSTANCE
        8 BASE
        9 REFLECTION-REDUCING FILM
        10 LIQUID CRYSTAL PANEL (OPERATION UNIT, DISPLAY PANEL)
        104 HOUSING
        E0 OPERATION AREA
        E1 NON-OPERATION AREA

## Claims

1. An electronic device including an operation area and a non-operation area positioned outside the operation area, the electronic device comprising:
an operation unit including a first principal surface and a second principal surface positioned opposite to the first principal surface, wherein the first principal surface is an initial incident ambient light surface;
a light shielding film formed on the first principal surface of the operation unit corresponding to the non-operation area; and
a vibrator provided on the second principal surface of the operation unit corresponding to the non-operation area,
wherein when a critical angle at which light is totally reflected by the second principal surface of the operation unit is represented by θ and sum of a thickness T1 of the operation unit and a thickness T2 of the vibrator is represented by T, the entire vibrator is provided, on the second principal surface of the operation unit corresponding to the non-operation area, at a position apart by T×tan δ or more from an end of the light shielding film which end is positioned on the operation area side, in sectional view.

2. The electronic device according to claim 1, wherein a reflection-reducing film having a reflectance lower than a reflectance of a surface of the vibrator is provided on the surface of the vibrator.

3. The electronic device according to claim 1, wherein
the vibrator has an opposed surface opposed to the second principal surface of the operation unit; a rear surface positioned opposite to the opposed surface, and four side surfaces adjacent to the opposed surface and the rear surface, and
the vibrator has an inclined portion provided between a side surface closest to the operation area among the four side surfaces, and the rear surface.

4. A mobile terminal comprising the electronic device according to claim 1, and a housing in which the electronic device is provided.

5. The electronic device according to claim 1, wherein
the operation unit is a touch panel, and
the electronic device further includes:
a base substance having a third principal surface;
a base that is provided on the third principal surface of the base substance and supports the operation unit at the non-operation area; and
a display panel that is provided on or above the third principal surface of the base substance and is disposed to be opposed to the operation unit with a space interposed therebetween.

6. The electronic device according to claim 5, wherein the display panel is one selected from a group consisting of a liquid crystal panel and an organic EL panel.

7. The electronic device according to claim 1, wherein
the operation unit is a display panel having a function of detecting an input position, and
the electronic device further includes:
a base substance having a third principal surface; and
a base that is provided on the third principal surface of the base substance and supports the operation unit at the non-operation area.

8. The electronic device according to claim 7, wherein the display panel is one selected from a group consisting of a liquid crystal panel and an organic EL panel.

9. An electronic device including an operation area and a non-operation area positioned outside the operation area, the electronic device comprising:
an operation unit including a first principal surface and a second principal surface positioned opposite to the first principal surface, wherein the first principal surface is an initial incident ambient light surface;
a light shielding film formed on the second principal surface of the operation unit corresponding to the non-operation area; and
a vibrator provided on the light shielding film,
wherein when a critical angle at which light is totally reflected by the second principal surface of the operation unit is represented by θ and a thickness of the vibrator is represented by T2, the entire vibrator is provided, on the light shielding film, at a position apart by T2×tan θ or more from an end of the light shielding film which end is positioned on the operation area side, in sectional view.

10. The electronic device according to claim 9, wherein the light shielding film includes an adhesive member that bonds the vibrator to the second principal surface of the operation unit.

11. The electronic device according to claim 9, wherein a reflection-reducing film having a reflectance lower than a reflectance of a surface of the vibrator is provided on the surface of the vibrator.

12. The electronic device according to claim 9, wherein
the vibrator has an opposed surface opposed to the second principal surface of the operation unit; a rear surface positioned opposite to the opposed surface, and four side surfaces adjacent to the opposed surface and the rear surface, and
the vibrator has an inclined portion provided between a side surface closest to the operation area among the four side surfaces, and the rear surface.

13. A mobile terminal comprising the electronic device according to claim 9, and a housing in which the electronic device is provided.

14. The electronic device according to claim 9, wherein
the operation unit is a touch panel, and
the electronic device further includes:
a base substance having a third principal surface;
a base that is provided on the third principal surface of the base substance and supports the operation unit at the non-operation area; and
a display panel that is provided on or above the third principal surface of the base substance and is disposed to be opposed to the operation unit with a space interposed therebetween.

15. The electronic device according to claim 14, wherein the display panel is one selected from a group consisting of a liquid crystal panel and an organic EL panel.

16. The electronic device according to claim 9, wherein
the operation unit is a display panel having a function of detecting an input position, and
the electronic device further includes:
a base substance having a third principal surface; and
a base that is provided on the third principal surface of the base substance and supports the operation unit at the non-operation area.

17. The electronic device according to claim 16, wherein the display panel is one selected from a group consisting of a liquid crystal panel and an organic EL panel.