JP4577096B2 - Display device, input device, and electronic device - Google Patents

Description

  The present invention relates to a display device, an input device, and an electronic device.

There is known a display device in which a coordinate input device (tablet) is provided on the front side or the back side of a liquid crystal panel that performs image display, and a pointing operation with a pen or a finger is possible. For example, Patent Document 1 discloses a liquid crystal panel in which an electromagnetic induction type tablet is disposed on the back side.
JP-A-9-160707

  In recent years, mobile phones having display units on both sides of a housing have appeared, and it is convenient for such a double-sided display device to perform a pointing operation by instructing the display surface with a pen or the like. However, if two display devices described in Patent Document 1 are provided back-to-back, the thickness of the display portion is remarkably large, which is extremely inconvenient in a mobile phone or the like that needs to be thin and lightweight.

  The present invention has been made in view of the above-mentioned problems of the prior art, and provides a thin and lightweight display device that can display two screens and can input coordinates via a display surface. The purpose is to do. Another object of the present invention is to provide a thin input device that enables coordinate input independent on both sides.

The display device of the present invention is a display device including a coordinate detection device, and is provided between a first sensor substrate, a second sensor substrate, and the first sensor substrate and the second sensor substrate that are electrically connected to each other. An input panel configured to include an electric field shielding layer disposed; a first display panel disposed on one side of the input panel; and an other side of the input panel. A second display panel; and an illuminating device disposed between the first display panel and the electric field shielding layer . Illumination light emitted from the illuminating device and transmitted through the electric field shielding layer is the second display panel . It is supplied to a display panel .

In the display device of the present invention, since the first sensor substrate and the second sensor substrate are disposed to face each other with the electric field shielding layer interposed therebetween, and one electric field shielding layer is shared by both sensor substrates, Compared to the case where two sensor substrates are provided back to back, the thickness can be reduced.
In addition, since the two sensor boards are electrically connected to each other, it is possible to share a driver for processing input information, and in that respect, it is possible to reduce the thickness and weight.
Furthermore, since a single lighting device is shared by both display panels without providing a lighting device for each display panel, the configuration can be reduced in thickness.
Therefore, it is possible to provide a thin and lightweight display device that can display two screens and can input independent coordinates on both sides.

The display device of the present invention is characterized in that the illumination device is disposed between the first sensor substrate and the second sensor substrate.
With such a configuration, except for the electric field shielding layer, the sensor substrate and the display panel are arranged sequentially with the illumination device as the center, and are arranged between the display panel and the illumination device. The number of layers is almost equal. In the display device of the present invention, there is a single illumination device, and the light emitted from both the front and back surfaces is used as illumination light. Therefore, the number of laminated members interposed between each display panel and the illumination device is made equal. Accordingly, equivalent illumination light can be used on both display surfaces.

In the display device of the present invention, the electric field shielding layer is made of a transparent conductive film formed on the surface of the lighting device.
If the electric field shielding layer is transparent, the illumination light emitted from the illumination device can be transmitted, and the illumination light can be efficiently used even in the display panel disposed on the electric field shielding layer side. .

In the display device according to the present invention, the electric field shielding layer is formed of a striped metal wiring formed on the surface of the lighting device.
Even if the electric field shielding layer is not light-transmitting, by using striped metal wiring, air gaps are generated between the metal wirings, and illumination light can be obtained through the air gaps. Therefore, the illumination light can be used efficiently also in the display panel disposed on the electric field shielding layer side.

In the display device of the present invention, the electric field shielding layer is made of a metal mesh.
Even if the electric field shielding layer is not light-transmitting, if it is a metal mesh, illumination light can be obtained through each mesh. Therefore, the illumination light can be used efficiently also in the display panel disposed on the electric field shielding layer side.

In the display device of the present invention, the first sensor substrate and the second sensor substrate are transparent or a half mirror.
The first sensor substrate and the second sensor substrate are disposed on the back side of the first display panel and the second display panel, respectively, and are interposed between each display panel and the illumination device. Therefore, if the sensor substrate is transparent, the illumination light from the illumination device can be transmitted and the display panel can be efficiently irradiated with the illumination light.
Further, if the first sensor substrate and the second sensor substrate are half mirrors, the illumination light emitted from the illumination device is transmitted, but the light incident from the opposite surface can be reflected. Therefore, even if the illumination light that has passed through the sensor substrate is reflected on the display panel surface and returns to the sensor substrate as stray light, it can be reflected on the mirror surface and reused as illumination light. Light can be irradiated.

In the display device of the present invention, the first sensor substrate, the second sensor substrate, and the electric field shielding layer are provided with light transmission openings, respectively.
Even if the first sensor substrate, the second sensor substrate, and the electric field shielding layer are not light-transmitting, by providing an opening for transmitting light in each of them, the illumination light can be transmitted through the opening. The illumination light can be used efficiently.

  In the display device of the present invention, it is preferable that the first sensor substrate and the second sensor substrate are connected by a flexible wiring substrate. If the connection is made using the flexible wiring board, the connection portion can be bent, so that the connection distance between the two sensor boards can be narrowed, and further reduction in thickness and weight can be achieved.

  Furthermore, in the display device of the present invention, it is preferable that the first sensor substrate and the second sensor substrate are formed on a single flexible substrate. By integrating both sensor substrates, the configuration can be further simplified, so that further reduction in thickness and weight can be achieved. Further, since the flexible substrate can be bent along a limited space in the housing, the storage space can be further reduced, and the thickness and weight can be reduced.

  The display panel is preferably a liquid crystal panel. Since the liquid crystal panel can also be reduced in thickness and weight, the display device can also be reduced in thickness and weight.

  An input device according to the present invention includes the display device according to the present invention. As described above, the display device of the present invention is formed by stacking two display panels on both sides of the input panel, so that independent coordinate inputs can be made on both sides corresponding to each sensor board. The thin and lightweight input device can be obtained.

Furthermore, an electronic apparatus according to the present invention includes the display device or the input device.
Since such an electronic device has display surfaces on both sides of the electronic device, the electronic device is a thin and lightweight electronic device capable of two-screen display. Furthermore, since each has an input device capable of independent coordinate input, it is possible to provide a thin and lightweight electronic device that can input by a pointing operation using a pen or the like according to each screen of the display surface.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings shown in the present embodiment, the film thicknesses and ratios of dimensions of the respective components are appropriately changed in order to make the drawings easy to see.
FIG. 1 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 100 which is an embodiment of the display device of the present invention.

  The liquid crystal display device 100 includes a tablet on the back. As shown in FIG. 1, the liquid crystal display device 100 includes an input panel 6, an illumination device 3 and a first liquid crystal panel ( A first display panel 1 and a second liquid crystal panel (second display panel) 2 disposed on the other side of the input panel 6 are accommodated in a housing 7.

  Various types of liquid crystal panels 1 and 2 can be used. That is, the liquid crystal panels 1 and 2 can be used without any problem regardless of whether they are of a transmission type, a reflection type, or a transflective display type. Applicable regardless of type.

The input panel 6 serves as a sensor unit of an electromagnetic induction type tablet, and is disposed on the back side of the liquid crystal panels 1 and 2.
The input panel 6 includes a first sensor substrate 4a, a second sensor substrate 4b, and an electric field shielding layer 5. Both the first sensor board 4a and the second sensor board 4b are formed by arranging sensor coil wires for coordinate detection on the board. Typically, the X-axis direction sensor coil is formed on one surface of the board. A wire having a Y axis direction sensor coil wire formed on the other surface is used. The first sensor substrate 4a and the second sensor substrate 4b are electrically connected to each other, are disposed opposite to each other with the electric field shielding layer 5 interposed therebetween, and are connected to a processing circuit (not shown) that processes the detected signal. Has been.

  The input panel 6 can transmit illumination light from the illumination device 3. In the display device of the present invention, the illumination light from the illumination device 3 is used as the backlight of the first liquid crystal panel 1 and the second liquid crystal panel. In the present embodiment shown in FIG. 1, since the input panel 6 is disposed between the second liquid crystal panel and the lighting device 3, the illumination light from the lighting device 3 needs to pass through the input panel 6.

  The electric field shielding layer 5 is not particularly limited as long as the electric field shielding layer 5 can transmit illumination light and has electric conductivity capable of shielding an electric field, and a transparent conductive film such as ITO (indium tin oxide) is formed on a transparent substrate. Examples thereof include those formed, metal wires such as copper formed on a transparent substrate in various shapes such as stripes or spirals, with a space provided between the wires, and metal meshes. Here, the metal mesh refers to a metal plate having a large number of holes that transmit illumination light, a metal foil, or the like, in addition to a mesh formed by braiding metal wires.

  In such a display device of the present invention, the first sensor substrate 4a and the second sensor substrate 4b are arranged to face each other and electrically connected to each other, and the single electric field shielding layer 5 is shared. Since the configuration can be simplified, the thickness and weight can be reduced. Moreover, since both sensor boards are electrically connected to each other, a processing circuit for processing the detected signal can be shared, and this also makes it possible to reduce the thickness and weight of the display device.

Furthermore, in the present embodiment, the first sensor substrate 4a and the second sensor substrate 4b are formed by forming the sensor coil wire on one flexible wiring substrate 4. The flexible wiring board 4 is bent in a U-shape at an intermediate portion thereof, and sensor coil wires arranged on the surface thereof are arranged so as to face the back surfaces of the liquid crystal panels 1 and 2. The electric field shielding layer 5 is accommodated in the U-shaped bent space.
In this case, the sensor coil wire corresponding to the first liquid crystal panel 1 and the sensor coil wire corresponding to the second liquid crystal panel 2 may be formed on the flexible wiring board 4 and connected to the processing circuit. Therefore, even when inputting from two display surfaces, there is no need to provide an input panel having a processing circuit and a sensor substrate for each surface, and the display device can be made thinner and lighter. It becomes.

  The first sensor substrate 4a and the second sensor substrate 4b are also capable of transmitting illumination light from the illumination device 3, similarly to the electric field shielding layer 5 described above. For this purpose, the first sensor substrate 4a and the second sensor substrate 4b are preferably transparent. Specifically, like the electric field shielding layer 5, a sensor coil wire made of a transparent conductive film is wired on a transparent substrate, or a sensor coil wire is placed on the transparent substrate with a gap between the sensor coil wires. For example, it is provided and wired. In any case, a dielectric multilayer film may be formed on one surface of the first sensor substrate 4a and the second sensor substrate 4b, and an antireflection coating may be formed on the other surface to form a half mirror. If it does in this way, the illumination light radiate | emitted from the illuminating device will permeate | transmit, but the light which injects from the opposite surface can be reflected. Therefore, even if the illumination light transmitted through the sensor substrate is reflected on the surface of the liquid crystal panel and returns to the sensor substrate as stray light, it can be reflected on the mirror surface and reused as illumination light. Light can be used.

  In addition, an opening for transmitting light may be provided in each of the first sensor substrate 4a, the second sensor substrate 4b, and the electric field shielding layer 5 so that the illumination light can be transmitted through the input panel 6. In this way, even if the input panel 6 is not light transmissive, each member is provided with a light transmitting opening, so that the illumination light can be transmitted through the opening. Light can be used efficiently. The shape and the number of the openings are not particularly limited, but a plurality of small openings may be used in order not to hinder the arrangement of the sensor coil wires and to not reduce the shielding effect of the electric field. It is preferable to arrange the openings uniformly. In this way, uniform illumination light can be irradiated to the liquid crystal panel.

  Further, in the display device of the present invention, two rigid substrates are prepared, and sensor coil wires are respectively disposed on the surface of the rigid substrate to form a first sensor substrate 4a and a second sensor substrate 4b. You may connect a board | substrate with a flexible wiring board. Even in this case, since the connection portion can be bent by electrically connecting the first and second sensor substrates 4a and 4b in a flexible state, the occupied portion of the connection portion can be reduced. Thus, the input panel 6 can be reduced in thickness and weight.

  The first liquid crystal panel 1 and the second liquid crystal panel 2 are disposed in openings on the front and back surfaces of the housing 7 so that two-screen display can be performed on both surfaces of the housing 7. Both the first liquid crystal panel 1 and the second liquid crystal panel 2 are connected to a main wiring board (not shown) on which the driver IC, the power supply IC, and the like, and the processing circuit of the tablet are mounted.

  The lighting device 3 is disposed between the first liquid crystal panel 1 and the input panel 6 and serves as a backlight for the liquid crystal panels 1 and 2. The illumination device 3 includes a light source (not shown) such as an LED and a light guide plate that emits light emitted from the light source as surface light emission. Various optical members may be provided on the light guide plate as necessary. For example, a diffusion sheet provided on the light exit surface side of the light guide plate in order to obtain more uniform surface light emission, a reflection sheet provided on the back surface side of the light guide plate in order to perform efficient light emission, and the like.

  As described above, in the present embodiment, even in a two-screen display type display device in which the two liquid crystal panels 1 and 2 are provided back to back, the first sensor substrate 4a constituting the input panel 6 and The second sensor substrate 4b is electrically connected, the electric field shielding layer 5 is sandwiched between the two sensor substrates, and the illumination device 3 is shared in the liquid crystal panels 1 and 2, thereby simplifying the configuration. , Can be thin and lightweight.

  Furthermore, the display device of the present invention indicates the display surfaces of the liquid crystal panels 1 and 2 provided on both surfaces of the housing 7 with a pointing device such as a pen, whereby the first sensor substrate on the back side of the liquid crystal panels 1 and 2 is used. Since coordinates can be detected independently by the 4a and the second sensor substrate 2b, independent input operations can be performed from the display screen of two screens. As described above, the input device of the present invention uses a display device that is thin and light, and thus is naturally thin and light.

  In the present embodiment, description is given using a tablet that performs coordinate detection by an electromagnetic induction method. However, the display device of the present invention is not limited to this, and an input panel for coordinate detection is used as a display panel. Other methods may be used as long as they can be arranged on the back side.

  FIG. 2 shows another embodiment of the display device of the present invention. The display device 101 shown in FIG. 2 is different from the liquid crystal display device 100 shown in FIG. 1 in that the illumination device 3 is integrated with the electric field shielding layer 5, and these are integrated between the first sensor substrate 4a and the second sensor substrate 4b. I have just put it in between. That is, the illumination device 3 is disposed in the input panel 6.

  The liquid crystal display device 101 of the present embodiment has a substantially symmetrical configuration in which the sensor substrates 4a and 4b and the liquid crystal panels 1 and 2 are sequentially arranged with the illumination device 3 as the center. And the difference of the member laminated | stacked between each sensor board | substrate 4a, 4b and the illuminating device 3 becomes only one layer of the electric field shielding layer 5, and the number of lamination | stacking members becomes substantially equal. In this embodiment, since the emitted light from both the front and back surfaces of the single illumination device 3 is used as illumination light, the number of laminated members interposed between each sensor substrate 4a, 4b and the illumination device 3 is made equal. Therefore, the same illumination light can be used on both display surfaces, which is preferable.

In the present embodiment, the electric field shielding layer 5 is disposed on the second sensor substrate 4b side, but the display device 101 of the present invention is not limited to this, and the electric field shielding is performed on any surface side of the lighting device 3. Layer 5 may be provided. However, when the areas of the display screens of the first liquid crystal panel 1 and the second liquid crystal panel 2 are different, the electric field shielding layer 5 is formed on the liquid crystal panel side with the smaller area in view of the use efficiency of the illumination light of the illumination device 3. Is preferably disposed.
Furthermore, the display device 101 of this embodiment can also be used as an input device in the same manner as the first embodiment shown in FIG.

  Next, the electronic apparatus of the present invention will be described with reference to FIGS. A mobile phone 1000 which is an embodiment of the electronic device of the present invention is a foldable mobile phone having a folded state shown in FIG. 3 and a use state shown in FIG. Part 1002.

  The liquid crystal display device 100 is arranged inside the display body portion 1002, and is configured such that the display body portion 1002 can visually recognize the display screen on the front side display surface 1003 and the back side display surface 1004. Then, pointing input is possible by instructing with the pen or the like on the front side display surface 1003 and the back side display surface 1004. Such a cellular phone 1000 is a two-screen display type, and is thin and lightweight although independent input is possible on the two screens.

  As described above, the display device, the input device, and the mobile phone according to the electronic device according to the embodiments of the present invention have been described. However, the present invention is not limited thereto, and various embodiments are possible without departing from the gist of the present invention. It is possible to make changes. For example, although the case where the display panel is a liquid crystal panel has been described in the present embodiment, the present invention can be applied without any problem as long as it is a display panel that transmits illumination light supplied from the back.

1 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device according to an embodiment of the present invention. Sectional drawing which shows schematic structure of the liquid crystal display device of other embodiment of this invention. The perspective view which shows the folding state of the electronic device of one Embodiment of this invention. FIG. 4 is a perspective view showing a usage state of the electronic device of FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st liquid crystal panel (1st display panel), 2 ... 2nd liquid crystal panel (2nd display panel), 3 ... Illuminating device, 4a ... 1st sensor substrate, 4b ... 2nd sensor substrate, 5 ... Electric field shielding layer , 6 ... input panel, 100 ... liquid crystal display device, 101 ... liquid crystal display device.

Claims (12)

A display device comprising a coordinate detection device,
An input panel configured to include a first sensor board and a second sensor board electrically connected to each other, and an electric field shielding layer disposed between the first sensor board and the second sensor board;
A first display panel disposed on one side of the input panel;
A second display panel disposed on the other side of the input panel;
A lighting device disposed between the first display panel and the electric field shielding layer ;
With
Illumination light emitted from the illumination device and transmitted through the electric field shielding layer is supplied to the second display panel . The display device according to claim 1, wherein the illumination device is disposed between the first sensor substrate and the electric field shielding layer .   The display device according to claim 1, wherein the electric field shielding layer is made of a transparent conductive film formed on a surface of the lighting device.   The display device according to claim 1, wherein the electric field shielding layer is formed of a stripe-shaped metal wiring formed on a surface of the lighting device.   The display device according to claim 1, wherein the electric field shielding layer is made of a metal mesh.   The display device according to any one of claims 1 to 5, wherein the first sensor substrate and the second sensor substrate are transparent or a half mirror.   6. The light-transmitting opening is provided in each of the first sensor substrate, the second sensor substrate, and the electric field shielding layer. 6. Display device.   The display device according to claim 1, wherein the first sensor substrate and the second sensor substrate are connected by a flexible wiring substrate.   The display device according to any one of claims 1 to 7, wherein the first sensor substrate and the second sensor substrate are formed on a single flexible substrate.   The display device according to claim 1, wherein the display panel is a liquid crystal panel.   An input device comprising the display device according to any one of claims 1 to 10.   An electronic apparatus comprising the display device according to any one of claims 1 to 10, or the input device according to claim 11.

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