JP2004205703A - Liquid crystal display panel and mobile device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device thinner than a conventional one for displaying a picture on the front side as well as on the rear side. <P>SOLUTION: The liquid crystal display panel is characterized by being equipped with a transmissive TN liquid crystal element which is set so as to transmit the first polarized light in a state with an applied electric field and to convert the first polarized light proceeding to the surface direction into the second polarized light proceeding to the surface direction in a state with no applied electric field, a reflective polarizing plate which is set so as to reflect the first polarized light transmitted through the transmissive TN liquid crystal element and to transmit the second polarized light resulting from conversion by the transmissive TN liquid crystal element proceeding to the surface direction and a polarizing plate which is set so as to be placed opposite to the reflective polarizing plate interposing the transmissive TN liquid crystal element in between for the purpose of transmitting the first polarized light. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device and a mobile device for displaying an image on both a front surface and a back surface.
[0002]
[Prior art]
A mobile device represented by a mobile phone is required to be thin and compact. Japanese Patent Application Laid-Open No. 2002-209001 discloses a display device and a mobile device for displaying an image on both the front surface and the back surface.
[0003]
[Patent Document 1]
JP-A-2002-209001
[Problems to be solved by the invention]
However, in the configuration disclosed in the above-described related art, in order to display an image on both the front surface and the back surface of the main body, a surface light emitting element for displaying an image on the front surface of the main body, and an image on the rear surface of the main body. It is necessary to provide a rear light emitting element for displaying. The surface light emitting element and the rear light emitting element need to be provided so as to overlap each other along the thickness direction of the mobile phone. For this reason, there is a problem that the thickness of the mobile phone is increased.
[0005]
The present invention has been made to solve such a problem, and an object of the present invention is to provide a thinner display device and a mobile device for displaying an image on both a front surface and a rear surface.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the liquid crystal display panel according to the present invention transmits the first polarized light toward the surface direction when the electric field is applied and transmits the first polarized light toward the surface direction when the electric field is not applied. A transmissive TN liquid crystal element provided to convert the light into a second polarized light, and a first light reflected by the transmissive TN liquid crystal element that reflects the first polarized light transmitted through the transmissive TN liquid crystal element. A reflective polarizer provided to transmit two polarized lights; and a polarizer provided to face the reflective polarizer with the transmissive TN liquid crystal element interposed therebetween to transmit the first polarized light. It is characterized by having.
[0007]
The mobile device according to the present invention transmits the first polarized light when an electric field is applied, and converts the first polarized light toward the surface direction into the second polarized light toward the surface direction when the electric field is not applied. A transmission type TN liquid crystal element provided to reflect the first polarized light transmitted through the transmission type TN liquid crystal element and transmitting the second polarized light toward the surface direction converted by the transmission type TN liquid crystal element. A reflection-type polarizing plate, a polarizing plate provided to face the reflection-type polarizing plate with the transmission-type TN liquid crystal element interposed therebetween to transmit the first polarized light, and a transmission-type TN liquid crystal element. In a state where the electric field is not applied, a main image is displayed by the second polarized light that has been converted by the transmissive TN liquid crystal element and transmitted through the reflective polarizer toward the surface. A front display screen arranged to face the transmissive TN liquid crystal element with the reflective polarizer interposed therebetween, and facing the rear surface in a state where the electric field is applied to the transmissive TN liquid crystal element. A rear display screen arranged to face the transmission TN liquid crystal element with the polarizing plate interposed therebetween to display a sub-image by the first polarization transmitted through the transmission TN liquid crystal element and the polarizing plate; A main body having a front surface provided with the front display screen and a back surface provided with the rear display screen is provided.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In the liquid crystal display panel according to the present embodiment, the first polarized light is transmitted when the electric field is applied, and the first polarized light toward the surface is converted to the second polarized light toward the surface when no electric field is applied. A transmission type TN liquid crystal element provided so as to reflect the first polarized light transmitted through the transmission type TN liquid crystal element and transmit the second polarized light directed toward the surface converted by the transmission type TN liquid crystal element. And a polarizing plate provided to face the reflective polarizing plate with a transmission TN liquid crystal element interposed therebetween to transmit the first polarized light.
[0009]
Therefore, the first polarized light transmitted through the polarizer toward the surface direction is transmitted through the transmissive TN liquid crystal element and reflected by the reflective polarizer when an electric field is applied to the transmissive TN liquid crystal element. Thereafter, the light passes through the transmission type TN liquid crystal element and the polarizing plate toward the back direction opposite to the surface direction, and is converted into the second polarized light by the transmission type TN liquid crystal element when no electric field is applied to the transmission type TN liquid crystal element. After that, the light passes through the reflective polarizing plate toward the surface. Therefore, an image can be displayed on both the front side and the back side by one liquid crystal element. As a result, a thinner liquid crystal display panel for displaying images on both the front surface and the back surface can be obtained.
[0010]
It is preferable that the polarization direction of the first polarization and the polarization direction of the second polarization are different from each other by about 90 degrees.
[0011]
The first polarized light transmitted through the polarizing plate toward the surface direction is transmitted through the transmission TN liquid crystal element and is reflected by the reflection polarizing plate when the electric field is applied to the transmission TN liquid crystal element. After being reflected, the light passes through the transmissive TN liquid crystal element and the polarizing plate toward a back direction opposite to the surface direction, and when the electric field is not applied to the transmissive TN liquid crystal element, After being converted into the second polarized light by the TN liquid crystal element, the light is preferably transmitted through the reflective polarizer toward the surface.
[0012]
In a state where the electric field is not applied to the transmission type TN liquid crystal element, the main body is displayed by the second polarized light converted by the transmission type TN liquid crystal element and transmitted through the reflection type polarizing plate toward the surface direction. A front display screen disposed so as to face the transmission TN liquid crystal element with a reflective polarizing plate interposed therebetween; and And a rear display screen arranged to face the transmission TN liquid crystal element with the polarizing plate interposed therebetween so as to display a sub-image by the first polarized light transmitted through the polarizing plate. Is preferred.
[0013]
In order to receive the first polarized light and to supply the first polarized light to the polarizing plate, it is preferable to further include a front light arranged to face the transmission TN liquid crystal element with the polarizing plate interposed therebetween.
[0014]
It is preferable that the apparatus further includes a light source provided to supply the first polarized light to the front light.
[0015]
In the mobile device according to the present embodiment, the first polarized light is transmitted when the electric field is applied, and the first polarized light toward the surface is changed to the second polarized light toward the surface when the electric field is not applied. A transmissive TN liquid crystal element provided for conversion; and a first polarized light transmitted through the transmissive TN liquid crystal element and reflecting so as to transmit a second polarized light directed toward the surface converted by the transmissive TN liquid crystal element. And a polarizing plate provided to face the reflective polarizing plate with a transmission TN liquid crystal element interposed therebetween to transmit the first polarized light.
[0016]
Therefore, the first polarized light transmitted through the polarizer toward the surface direction is transmitted through the transmissive TN liquid crystal element and reflected by the reflective polarizer when an electric field is applied to the transmissive TN liquid crystal element. Thereafter, the light passes through the transmission type TN liquid crystal element and the polarizing plate toward the back direction opposite to the surface direction, and is converted into the second polarized light by the transmission type TN liquid crystal element when no electric field is applied to the transmission type TN liquid crystal element. After that, the light passes through the reflective polarizing plate toward the surface. Therefore, an image can be displayed on both the front display screen and the rear display screen with one liquid crystal element. As a result, a thinner mobile device for displaying images on both the front display screen and the rear display screen can be obtained.
[0017]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a perspective view of mobile device 150 according to the present embodiment as viewed from the front side, and FIG. 2 is a perspective view of mobile device 150 as viewed from the back side. The mobile device 150 is, for example, a mobile phone, and includes the main body 12 having a substantially plate shape. A cylindrical antenna 15 is provided on a side surface formed along a direction perpendicular to the longitudinal direction of the main body 12 so as to protrude along the longitudinal direction of the main body 12. The antenna 15 is provided for transmitting and receiving audio information and other data.
[0019]
On a surface 13 formed on the main body 12, a surface display screen 8 having a substantially square shape is provided on the antenna 15 side. On a back surface 14 formed on the main body 12, a substantially square back surface display screen 9 is provided on the antenna 15 side. The front display screen 8 and the rear display screen 9 have substantially the same shape as each other, and are arranged at positions facing each other.
[0020]
The front display screen 8 and the rear display screen 9 can efficiently classify and display the contents of various services provided by the mobile device 150. The front display screen 8 and the rear display screen 9 can display the same contents as each other, and can be independent of each other by providing electronic circuits for driving the front display screen 8 and the rear display screen 9 independently of each other. The displayed content can be displayed.
[0021]
A plurality of keyboards 18 arranged in a matrix are arranged on the opposite side of the front surface display screen 8 on the front surface 13 formed on the main body 12. A plurality of keyboards 19 arranged in a matrix are arranged on the opposite side of the rear display screen 9 on the rear surface 14 formed on the main body 12. The keyboard 18 and the keyboard 19 are provided for inputting numbers, characters, and symbols to the mobile device 150.
[0022]
A surface mode switching button 16 is provided between the surface display screen 8 on the surface 13 formed on the main body 12 and the plurality of keyboards 18. A back mode switching button 17 is provided between the back display screen 9 and the plurality of keyboards 19 on the back 14 formed on the main body 12. The front mode switching button 16 and the rear mode switching button 17 are provided for selecting various service functions or selecting input of kana, hiragana, alphanumeric characters, and the like from the keyboard 18 and the keyboard 19, respectively.
[0023]
A side surface formed on the main body 12 along the longitudinal direction of the main body 12 is provided with a strap 20 formed in a ring shape by a cord-like member.
[0024]
FIG. 3 is a cross-sectional view showing the configuration of liquid crystal display panel 100 provided in mobile device 150 according to the present embodiment, and FIG. 4 is a schematic cross-sectional view for explaining the operation of liquid crystal display panel 100.
[0025]
The liquid crystal display panel 100 includes a transmission TN liquid crystal element 2. The transmissive TN liquid crystal element 2 transmits the first polarized light 4 in a state where an electric field is applied, and converts the first polarized light 4 traveling in the surface direction 6 into a second polarized light 5 traveling in the surface direction 6 when no electric field is applied. It is provided to convert. The polarization direction of the first polarization 4 and the polarization direction of the second polarization 5 are different from each other by about 90 degrees.
[0026]
The reflective polarizing plate 3 is provided on the liquid crystal display panel 100. The reflective polarizing plate 3 is provided so as to reflect the first polarized light 4 transmitted through the transmission TN liquid crystal element 2 and transmit the second polarized light 5 toward the surface direction 6 converted by the transmission TN liquid crystal element 2. ing.
[0027]
The liquid crystal display panel 100 includes the polarizing plate 1. The polarizing plate 1 is provided so as to face the reflective polarizing plate 3 with the transmission TN liquid crystal element 2 interposed therebetween in order to transmit the first polarized light 4.
[0028]
The surface display screen 8 provided on the front surface 13 formed on the main body 12 of the mobile device 150 is converted by the transmission TN liquid crystal element 2 toward the surface direction 6 when no electric field is applied to the transmission TN liquid crystal element 2. In order to display a main image with the second polarized light 5 transmitted through the reflective polarizing plate 3, it is arranged to face the transmissive TN liquid crystal element 2 with the reflective polarizing plate 3 interposed therebetween.
[0029]
The rear display screen 9 provided on the rear surface 14 formed on the main body 12 of the mobile device 150 has the transmission TN liquid crystal element 2 and the rear display screen 9 facing the rear direction 7 when an electric field is applied to the transmission TN liquid crystal element 2. In order to display a sub-image by the first polarized light 4 transmitted through the polarizing plate 1, it is arranged to face the transmission TN liquid crystal element 2 with the polarizing plate 1 interposed therebetween.
[0030]
The liquid crystal display panel 100 is provided with a front light 10. The front light 10 is disposed between the polarizing plate 1 and the rear display screen 9 to receive the first polarized light 4 and supply the first polarized light 4 to the polarizing plate 1.
[0031]
The liquid crystal display panel 100 includes a light source 11. The light source 11 is provided to supply the first polarized light 4 to the front light 10.
[0032]
In the liquid crystal display panel 100 thus configured, when the light source 11 supplies the first polarized light 4 to the front light 10, the front light 10 changes the traveling direction of the first polarized light 4 and supplies it to the polarizing plate 1. . Then, the first polarized light 4 supplied from the front light 10 to the polarizing plate 1 passes through the polarizing plate 1 toward the surface direction 6.
[0033]
In an ON state in which an electric field is applied to the transmissive TN liquid crystal element 2, the first polarized light 4 transmitted through the polarizing plate 1 toward the surface direction 6 transmits through the transmissive TN liquid crystal element 2 toward the surface direction 6. . Then, the first polarized light 4 transmitted through the transmissive TN liquid crystal element 2 toward the surface direction 6 is reflected by the reflective polarizing plate 2. Next, the first polarized light 4 reflected by the reflective polarizing plate 2 passes through the transmissive TN liquid crystal element 2, the polarizing plate 1 and the front light 10 toward the back direction 7, and forms a sub-image on the back display screen 9. indicate.
[0034]
In an off state in which no electric field is applied to the transmissive TN liquid crystal element 2, the first polarized light 4 transmitted through the polarizing plate 1 toward the surface direction 6 is converted into the second polarized light 5 by the transmissive TN liquid crystal element 2. You. After that, the second polarized light 5 converted by the transmissive TN liquid crystal element 2 is transmitted through the reflective polarizing plate 3 toward the surface direction 6 to display a main image on the front display screen 8.
[0035]
Thus, the transmission type TN liquid crystal element 2 to which the electric field is applied is turned on on the rear display screen 9 and turned off on the front display screen 8. The transmissive TN liquid crystal element 2 to which no electric field is applied is turned off on the rear display screen 9 and turned on on the front display screen 8. Accordingly, a positive display is performed on the front display screen 8, and a negative display of the image displayed on the front display screen 8 can be performed on the rear display screen 9.
[0036]
As described above, according to the present embodiment, when the electric field is applied, the first polarized light 4 is transmitted, and when the electric field is not applied, the first polarized light 4 traveling in the surface direction 6 is changed to the first polarized light 4 traveling in the surface direction 6. A transmissive TN liquid crystal element 2 provided to convert the light into two polarized lights 5, and the first polarized light 4 transmitted through the transmissive TN liquid crystal element 2 is reflected and directed toward a surface direction 6 converted by the transmissive TN liquid crystal element 2. A reflective polarizing plate 3 provided to transmit the second polarized light 5 and a reflective polarizing plate 3 provided to transmit the first polarized light 4 with the transmissive TN liquid crystal element 2 interposed therebetween. And a polarizing plate 1.
[0037]
Therefore, the first polarized light 4 transmitted through the polarizing plate 1 toward the surface direction 6 transmits through the transmissive TN liquid crystal element 2 and reflects the polarized light when the electric field is applied to the transmissive TN liquid crystal element 2. After being reflected by the plate 3, the light passes through the transmissive TN liquid crystal element 2 and the polarizing plate 1 toward the rear direction 7 opposite to the surface direction 6, and in a state where no electric field is applied to the transmissive TN liquid crystal element 2, After being converted into the second polarized light 5 by the transmissive TN liquid crystal element 2, the light is transmitted through the reflective polarizing plate 3 toward the surface direction 6. Therefore, an image can be displayed on both the front side and the back side by one liquid crystal element. As a result, a thinner liquid crystal display panel for displaying images on both the front surface and the back surface can be obtained.
[0038]
Further, since the display device can be constituted by one liquid crystal element, the cost is reduced to about two thirds of the conventional constitution.
[0039]
In this embodiment, an example is shown in which the present invention is applied to a mobile phone having a substantially plate-shaped main body, but the present invention is not limited to this. The present invention can also be applied to a foldable mobile phone configured to be freely foldable.
[0040]
Further, the example of the mobile phone in which the keyboard and the switching button are provided on both the front surface and the rear surface of the main body has been described. Good.
[0041]
Further, an example has been shown in which the front display screen and the rear display screen have the same shape, but the present invention is not limited to this. For example, the rear display screen may be configured to be smaller than the front display screen.
[0042]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a thinner display device and a mobile device for displaying an image on both the front surface and the back surface.
[Brief description of the drawings]
FIG. 1 is a perspective view of a mobile device according to the present embodiment as viewed from the front side. FIG. 2 is a perspective view of a mobile device according to the present embodiment as viewed from the back side. FIG. FIG. 4 is a cross-sectional view illustrating the configuration of a liquid crystal display panel. FIG. 4 is a schematic cross-sectional view illustrating the operation of the liquid crystal display panel according to the present embodiment.
REFERENCE SIGNS LIST 1 polarizing plate 2 transmissive TN liquid crystal element 3 reflective polarizing plate 4 polarized light 5 polarized light 6 front direction 7 back direction 8 front display screen 9 rear display screen 10 front light 11 light source 12 main body 13 front 14 back

Claims (7)

A transmission type TN liquid crystal provided to transmit the first polarized light when an electric field is applied and to convert the first polarized light toward the surface to the second polarized light toward the surface when the electric field is not applied. Element,
A reflective polarizing plate provided to reflect the first polarized light transmitted through the transmissive TN liquid crystal element and transmit the second polarized light toward the surface direction converted by the transmissive TN liquid crystal element;
A liquid crystal display panel comprising: a polarizing plate provided to face the reflective polarizing plate with the transmission TN liquid crystal element interposed therebetween to transmit the first polarized light. 2. The liquid crystal display panel according to claim 1, wherein the polarization direction of the first polarization and the polarization direction of the second polarization are different from each other by about 90 degrees. The first polarized light transmitted through the polarizing plate toward the surface direction passes through the transmissive TN liquid crystal element and is reflected by the reflective polarizing plate when the electric field is applied to the transmissive TN liquid crystal element. After being reflected, the light passes through the transmissive TN liquid crystal element and the polarizing plate toward the back direction opposite to the surface direction, and when the electric field is not applied to the transmissive TN liquid crystal element, 2. The liquid crystal display panel according to claim 1, wherein after being converted into the second polarized light by the TN liquid crystal element, the liquid crystal display panel transmits through the reflective polarizer toward the surface. In a state where the electric field is not applied to the transmission type TN liquid crystal element, the main body is displayed by the second polarized light converted by the transmission type TN liquid crystal element and transmitted through the reflection type polarizing plate toward the surface direction. A surface display screen arranged so as to face the transmission TN liquid crystal element with a reflection polarizing plate interposed therebetween;
In a state where the electric field is applied to the transmissive TN liquid crystal element, the polarizing plate is used to display a sub-image by the first polarized light transmitted through the transmissive TN liquid crystal device and the polarizing plate toward the rear direction. 2. The liquid crystal display panel according to claim 1, further comprising: a rear display screen disposed so as to face the transmissive TN liquid crystal element therebetween. 2. The liquid crystal display panel according to claim 1, further comprising a front light arranged to face the transmission TN liquid crystal element with the polarizing plate interposed therebetween to receive the first polarized light and supply the received first polarized light to the polarizing plate. The liquid crystal display panel according to claim 5, further comprising a light source provided to supply the first polarized light to the front light. A transmission type TN liquid crystal provided to transmit the first polarized light when an electric field is applied and to convert the first polarized light toward the surface to the second polarized light toward the surface when the electric field is not applied. Element,
A reflective polarizing plate provided to reflect the first polarized light transmitted through the transmissive TN liquid crystal element and transmit the second polarized light toward the surface direction converted by the transmissive TN liquid crystal element;
A polarizing plate provided so as to face the reflective polarizing plate with the transmission TN liquid crystal element interposed therebetween to transmit the first polarized light;
In a state where the electric field is not applied to the transmission type TN liquid crystal element, the main body is displayed by the second polarized light converted by the transmission type TN liquid crystal element and transmitted through the reflection type polarizing plate toward the surface direction. A surface display screen arranged so as to face the transmission TN liquid crystal element with a reflection polarizing plate interposed therebetween;
In a state where the electric field is applied to the transmissive TN liquid crystal element, the polarizing plate is used to display a sub-image by the first polarized light transmitted through the transmissive TN liquid crystal device and the polarizing plate toward the rear direction. A rear display screen disposed so as to face the transmissive TN liquid crystal element therebetween;
A mobile device comprising: a main body having a front surface provided with the front display screen and a back surface provided with the rear display screen.

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