JP2004205747A - Display device and electronic equipment - Google Patents

Abstract

An object of the present invention is to provide a double-sided display device which enables a single flat display to be viewed from two directions.
An optical display element in which a scattering substance for controlling transmission or scattering of light by selection of voltage application is sandwiched, and arranged on one surface and the other surface of the optical display element with their absorption axes orthogonal to each other. When the scattering substance is in a transmission state, the light incident from the first polarizing layer is absorbed by the second polarizing layer and the light incident from the second polarizing layer is formed. Is absorbed by the first polarizing layer, and when the scattering substance is in a scattering state, the light incident from the first and second transparent substrates becomes scattered light and passes through the first and second polarizing layers to form a scattered light. 1. A double-sided display device which emits light outside the second polarizing layer.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device and electronic equipment using light scattering.
[0002]
[Prior art]
Conventionally, a display device provided with a liquid crystal type flat display such as a computer has only one display surface, and can be viewed only from one direction. On the other hand, in order to view the display from both the front and back sides of the display device, two sets of flat displays must be provided inside the display device. (For example, refer to Patent Document 1.)
It is also considered that one display device is provided with a rotation axis to rotate the display surface by 180 ° so that the display can be viewed from both directions. (For example, see Patent Document 2.)
[0003]
[Patent Document 1]
JP 2001-290445 A (Page 4, FIG. 1)
[Patent Document 2]
JP-A-6-250156 (page 4, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, since the former display surface is a combination of two sets of flat displays, the number of parts is increased, the weight is heavy, the price is high, the shape is large, and the power consumption is large. In addition, since the latter display method is provided with a rotation axis to change the direction of the display surface, there are problems that the mechanical portion becomes large, and that the display surface is liable to break down or become dirty. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a display device capable of displaying both front and back sides with one flat panel display.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a display device according to claim 1 of the present invention comprises a first and a second transparent substrate having first and second transparent electrodes formed on opposing inner surfaces, respectively. An optical display element sealed between the first and second transparent substrates to scatter light when no voltage is applied between the first and second transparent electrodes and to transmit light when a voltage is applied; A first polarizing layer disposed outside; and a second polarizing layer disposed outside the second transparent substrate such that an absorption axis is orthogonal to the first polarizing layer. And With such a configuration, it is possible to realize a double-sided display device that enables viewing from two directions on one flat display.
[0006]
According to another aspect of the present invention, there is provided an electronic device comprising: a device case having openings formed on opposing surfaces; and a display device housed in the device case. The apparatus includes first and second transparent substrates having first and second transparent electrodes formed on opposing inner surfaces, respectively, and the first and second transparent substrates sealed between the first and second transparent substrates. An optical display element that scatters light when no voltage is applied between the transparent electrodes and transmits light when a voltage is applied, a first polarizing layer disposed outside the first transparent substrate, A second polarizing layer disposed outside the second transparent substrate such that the layer and the absorption axis are orthogonal to each other. With such a configuration, it is possible to realize an electronic device that enables viewing from two directions on one flat display.
Further, the present invention can be applied to a mobile phone as described in claim 3 of the present invention.
[0007]
According to another aspect of the present invention, there is provided an electronic device comprising: a device case having openings formed on opposing surfaces; a display device housed in the device case; and display data to be displayed on the display device. The display device comprises a first and a second transparent substrate having first and second transparent electrodes formed on opposing inner surfaces, respectively, and the first and the second transparent substrates. An optical display element encapsulated between the first and second transparent substrates and scatters light when no voltage is applied between the first and second transparent electrodes and transmits light when a voltage is applied; A first polarizing layer disposed at
A first polarizing layer and a second polarizing layer disposed outside the second transparent substrate such that an absorption axis is orthogonal to the first polarizing layer, wherein the display control means is configured to display data for inverting the display data. It is an object of the present invention to provide an electronic device comprising a reversing means. With such a configuration, when one display data is viewed from both sides of the electronic device, the display can be viewed in a correct direction from both sides.
Further, the present invention can be applied to an electronic device in which the operation unit case and the device case are openably and closably mounted as described in claim 5 of the present invention. With such a configuration, the display can be visually recognized in a correct direction regardless of whether the operation unit case and the device case are open or closed.
Further, the present invention can be applied to an openable / closable mobile phone as described in claim 6 of the present invention.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
[0009]
(First Embodiment)
FIG. 1 is a cross-sectional view of the first embodiment. The display device according to this embodiment includes polarizing films 1, 2 and a liquid crystal cell 3 (optical display element). The liquid crystal cell 3 includes transparent glass substrates 5 and 6 arranged opposite to each other, and the polarizing films 1 and 2 are arranged on the outer surfaces of the glass substrates 5 and 6 respectively. A transparent common electrode 7 is provided on the inner surface of the glass substrate 5, and transparent pixel electrodes 8A, 8B, 8C... Are arranged in a matrix on the inner surface of the glass substrate 6, and the respective pixel electrodes 8A, 8B , 8C,... Are connected to TFTs (thin film transistors) 9A, 9B, 9C,. Each of the TFTs 9A, 9B, 9C,... Has a scanning line (not shown) provided along the row direction of the pixel electrodes 8A, 8B, 8C,. These are connected to provided signal lines (also not shown).
The scattering material layer 10 is sealed between the glass substrates 5 and 6. As the scattering material layer 10, for example, a polymer dispersed liquid crystal layer, a polymer network type liquid crystal layer, or the like is used. In this case, the scattering material layer 10 may be of any type as long as the orientation order changes depending on the presence or absence of an applied voltage so that light can be scattered or transmitted. .
[0010]
FIG. 2 shows the relationship between the light absorption axis 1a of the polarizing film 1 and the light absorption axis 2a of the polarizing film 2. The polarizing films 1 and 2 are arranged so that their absorption axes are orthogonal to each other. Things.
[0011]
Next, a display operation of the display device will be described. FIG. 3 is a diagram for explaining a display operation. When the voltage is applied to the pixel electrode 8A by turning on the TFT 9A and the voltage is not applied to the pixel electrode 8B by turning off the TFT 9B, the incident light 11 transmitted from the glass substrate 5 through the polarizing film 1 In the vicinity of 8A, the liquid crystal is in a transmission state and transmits through the scattering material layer 10 to reach the polarizing film 2. At this time, since the absorption axis 1a of the polarizing film 1 is orthogonal to the absorption axis 2a of the polarizing film 2, light transmitted through the polarizing film 1 is absorbed by the polarizing film 2 and viewed from the glass substrate 5. However, it looks black even when viewed from the glass substrate 6. On the other hand, in the vicinity of the pixel electrode 8B to which no voltage is applied, the liquid crystal is in a scattered state, and among the light scattered by the scattering material layer 10, backward scattered light 21b and forward scattered light 21f are generated. Some of these scattered lights 21b and 21f pass through the polarizing films 1 and 2 and are observed by a viewer on the glass substrate 5 side and a viewer on the glass substrate 6 side as white display or gray display.
[0012]
FIG. 4 similarly shows the incident light 12 from the glass substrate 6 side. The incident light 12 transmitted from the glass substrate 6 through the polarizing film 2 becomes black in the vicinity of the pixel electrode 8A, and the backward scattered light 22b of the light scattered by the scattering material layer 10 in the vicinity of the pixel electrode 8B. A forward scattered light 22f is generated. Some of these scattered lights 22b and 22f pass through the polarizing films 1 and 2 and are observed as white display or gray display by an observer on the glass substrate 5 side and an observer on the glass substrate 6 side.
FIGS. 5A and 5B are examples in which “01:23” is displayed as display information. FIG. 5A is a view from the polarizing film 2 side, that is, the glass substrate 6 side. Only the light passing through the pixel to which the voltage is applied is incident on the back side polarizing film 1, and the incident light is absorbed. Is displayed in black. FIG. 5B shows this state as viewed from the polarizing film 1 side, that is, from the glass substrate 5 side, and the display content in FIG. By changing the signal applied to the signal lines along the column direction (vertical direction in the figure) according to the observation direction (not shown), "01:23" is displayed correctly in the observation direction. be able to.
The inversion of the display data will be specifically described in a second embodiment described later.
[0013]
In the first embodiment, the glass substrates 5 and 6 are used as transparent substrates, but a plastic film or the like may be used instead of glass. Although a polarizing film was used as the polarizing layer, a polarizing film formed directly on the outer surface of the transparent substrate may be used. Further, the display method of the TFT method is used as the display method, but other display driving methods such as a passive driving method may be used.
[0014]
(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is an example of a mobile phone as an electronic device using the display device of the present invention, and FIG. 7 is a cross-sectional view taken along line AA of FIG. 6 and 7, the mobile phone has an operation unit case 32 and a display unit case 31 that are freely opened and closed via a hinge mechanism 30. A display device including the polarizing film 1, the liquid crystal cell 3, and the polarizing film 2 described with reference to FIG. 1 is incorporated in the display unit case 31, and display contents can be visually recognized from two viewing directions indicated by arrows A and B. Openings 31A and 31B are formed as described above.
In this mobile phone, when the display unit case 31 is closed, the display contents can be viewed from the polarizing film 2 side. When the display unit case 31 of the mobile phone is opened, the display contents can be displayed from both sides of the polarizing films 1 and 2. You can see the contents. That is, in the mobile phone, the display content can be viewed from the viewing direction B side in the closed state, and the display content can be viewed from the viewing direction A side or the B side by changing the display signal in the open state. And enables observation from two directions on one flat display.
[0015]
FIG. 8 shows an example of a display control flow in which display data of the above-mentioned display device is controlled by the CPU. When display data is created (step S1), the display mode is determined (step S2). For example, the display mode is set to display mode A when the display unit case 31 is opened, and is controlled so as to be displayed in a correct direction when viewed from the observation direction A side (step S3). Then, control is performed so as to be displayed in a correct direction when viewed from the observation direction B side (step S4).
The switching of the display mode A / B is not limited to the opening and closing of the case, but may be switched by a switch, a sensor, an operation mode for observing from the front or back, or the like.
[0016]
Further, in the above example, an example of a mobile phone is shown. However, as an application example to other electronic devices, the present invention can be applied to operation devices such as a calculator, a clock, and various remote controllers.
As described above, according to the present invention, observation from two directions is possible with one display element, and an electronic device using this display device uses a window that can be observed from both sides as a display device. Can be. For example, a display device can be attached to a window glass of a vehicle or a door, and information can be displayed by switching to an outward or inward direction. Further, it can be used for a display portion of an openable / closable device such as a calculator, a clock, a telephone, and various operating devices such as a remote controller.
Further, if a control means for inverting the display is provided, the display can be viewed in the correct direction from both sides.
In addition, if the present invention is applied to an electronic device such as an openable / closable mobile phone, the display can be visually recognized in a correct direction regardless of whether the case is opened or closed.
[0017]
【The invention's effect】
The display device of the present invention enables observation from two directions with one display element, and an electronic device using this display device can use a window that can be observed from both sides as a display device. Further, by providing the control means for inverting the display, the display can be viewed in the correct direction from both sides.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a display device to which the present invention is applied.
FIG. 2 is a layout diagram of components of the display device of FIG. 1;
FIG. 3 is a cross-sectional view showing the operation of the display device of FIG.
FIG. 4 is an explanatory diagram in the case of incident light from the glass substrate 6 side in FIG.
FIG. 5 is an example of display of display information of the display device of FIG. 1;
6 is an example of a mobile phone using the display device of FIG.
7 is an enlarged partial cross-sectional view of the mobile phone of FIG.
FIG. 8 is a flowchart illustrating an example of display control of the mobile phone in FIG. 7;
[Explanation of symbols]
1, 2 polarizing film 3 liquid crystal cell 5, 6 glass substrate 7 common electrode 8 pixel electrode 9 TFT
Reference Signs List 10 scattering material layers 11, 12 incident light 21b, 21f, 22b, 22f scattered light 30 hinge mechanism 31 display unit case 32 operation unit case

Claims (6)

First and second transparent substrates having first and second transparent electrodes formed on opposing inner surfaces, respectively;
An optical display element that is sealed between the first and second transparent substrates and scatters light when no voltage is applied between the first and second transparent electrodes and transmits light when a voltage is applied;
A first polarizing layer disposed outside the first transparent substrate;
A display device comprising: the first polarizing layer; and a second polarizing layer disposed outside the second transparent substrate so that an absorption axis is orthogonal to the first polarizing layer. In an electronic device including a device case having openings formed on opposing surfaces, and a display device housed inside the device case,
The display device includes first and second transparent substrates each having first and second transparent electrodes formed on opposing inner surfaces,
An optical display element that is sealed between the first and second transparent substrates and scatters light when no voltage is applied between the first and second transparent electrodes and transmits light when a voltage is applied;
A first polarizing layer disposed outside the first transparent substrate;
An electronic apparatus, comprising: a first polarizing layer and a second polarizing layer disposed outside the second transparent substrate so that an absorption axis is orthogonal to the first polarizing layer. The electronic device according to claim 2, wherein the electronic device is a mobile phone. In an electronic device equipped with a device case having openings formed on opposing surfaces, a display device housed inside the device case, and display control means for controlling display data to be displayed on the display device,
The display device includes first and second transparent substrates each having first and second transparent electrodes formed on opposing inner surfaces,
An optical display element that is sealed between the first and second transparent substrates and scatters light when no voltage is applied between the first and second transparent electrodes and transmits light when a voltage is applied;
A first polarizing layer disposed outside the first transparent substrate;
A first polarizing layer and a second polarizing layer disposed outside the second transparent substrate so that an absorption axis is orthogonal to the first polarizing layer;
An electronic device, wherein the display control means includes display data inversion means for inverting the display data. An operation unit case is attached to the electronic device so as to be openable and closable with the device case,
The display control means displays the display data so that the operation unit case and the device case are read from the inner surface direction when the operation unit case and the device case are open, and the operation unit case and the device case are closed. 5. The electronic device according to claim 4, wherein the control is performed such that the display data is displayed such that the display data is read from the outer surface direction. The electronic device according to claim 5, wherein the electronic device is a mobile phone.

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