JPH08313895A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To make it possible to display images of private contents even in a public place by providing the outer side of a pair of transparent electrode substrates with a pair of rotatably disposed polarizing plates at least one of which are formed removable. CONSTITUTION: A liquid crystal display panel P is composed of a pair of the transparent electrode substrates 1, 2, sealing members and liquid crystals 8. The polarizing plate 9 is arranged to face the transparent electrode substrate 1 on the outer side of the transparent electrode substrate 1 existing on the rear surface side of this liquid crystal display panel P and the polarizing plate 10 is arranged to face the transparent electrode substrate 2 on the outer side of the substrate 2 existing on the front surface side. A pair of these polarizing plates 9, 10 have a rectangular shape of the same size as the size of the transparent electrode substrates 1, 2 and are so arranged that the respective angles of polarization vary relatively by 90 deg. from each other. The images of the contents not desired to be viewed by a third person are, therefore, displayed freely and are made visible anytime without being restricted by the presence of the third person and without being viewed by the third person.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art In a TN (Twisted Nematic) type liquid crystal display device, nematic liquid crystal is passed from one transparent electrode substrate to another transparent electrode substrate between a pair of transparent electrode substrates which are opposed to each other with a seal member interposed therebetween. A unit is constructed by enclosing it with a twist angle of 90 degrees, and polarizing plates are arranged outside the pair of transparent electrode substrates with a predetermined polarization angle (90 degrees).

In this liquid crystal display device, when no voltage is applied between the electrodes of the pair of transparent electrode substrates, the liquid crystal molecules of the nematic liquid crystal are twisted. By combining the polarization angles of the plates,
The incident light from the outside is transmitted and the display screen becomes cloudy.
On the other hand, when a voltage is applied between the electrodes of the pair of transparent electrode substrates, the liquid crystal molecules of the nematic liquid crystal are aligned in the direction perpendicular to the transparent electrode substrate, and due to the combination of the behavior of this liquid crystal and the polarization angle of the pair of polarizing plates, Black light is displayed on the display screen because incident light from the outside cannot be transmitted.

The TN type liquid crystal display device is widely used as an image display device in information equipment, communication equipment and the like because it has advantages of small size and excellent low power consumption characteristics.

[0005]

However, this conventional liquid crystal display device has the following problems. That is, in the conventional liquid crystal display device, all images are directly displayed on the display surface, and anyone can see the image displayed on the display surface. As a result, anyone can see the image displayed on the display screen. The contents of can be read.

By the way, when an information device or a communication device incorporating a liquid crystal display device is used, the contents of the image displayed on the display screen of the liquid crystal display device should not be known to a third party depending on the application. Sometimes there is. In this case,
The image displayed on the display screen of the liquid crystal display device is viewed by a third party, and it is difficult for the contents of the image to be read, so that the image is displayed when no one is around. For this reason, even if an image of a content that a third party does not want to be known is displayed on the display screen of the conventional liquid crystal display device, it cannot be freely displayed and viewed at any time due to the presence of the third party. However, there is a problem that it is not possible to display images of private contents such as documents in public places such as trains.

The present invention has been made based on the above-mentioned circumstances, and at any time without being restricted by the existence of a third party, an image having contents that the third party does not want to know is not seen by the third party. An object of the present invention is to provide a liquid crystal display device that can be freely displayed and viewed.

[0008]

According to another aspect of the present invention, there is provided a liquid crystal display device, wherein a pair of transparent electrode substrates provided facing each other and spaced apart from each other and a pair of transparent electrode substrates are enclosed with a predetermined twist angle. A nematic liquid crystal, and a pair of polarizing plates which are arranged outside the pair of transparent electrode substrates with a predetermined polarization angle and at least one of which is removable from the arranged position.

According to a second aspect of the present invention, there is provided a liquid crystal display device comprising a pair of transparent electrode substrates provided facing each other, a nematic liquid crystal enclosed between the pair of transparent electrode substrates with a predetermined twist angle, and the pair of transparent electrode substrates. A pair of polarizing plates arranged relatively outside the transparent electrode substrate with a predetermined polarization angle, one of which is rotatable on a plane parallel to the transparent electrode substrate, and the other of which is removable with respect to the arrangement position. And a polarizing plate for reading an image displayed on the liquid crystal display panel, and a polarizing plate holder for rotatably holding the polarizing plate.

According to a third aspect of the present invention, in the liquid crystal display device according to the second aspect, the polarizing plate arranged at the arrangement position and the polarizing plate held by the polarizing plate holder are rotationally driven in synchronization with each other. A polarizing plate rotating means is provided.

According to another aspect of the present invention, there is provided a liquid crystal display device comprising a pair of transparent electrode substrates provided facing each other, a nematic liquid crystal enclosed between the pair of transparent electrode substrates with a predetermined twist angle, and the pair of transparent electrode substrates. A liquid crystal display panel having a first polarizing plate arranged outside one of the transparent electrode substrates, and a second liquid crystal display panel provided separately from the liquid crystal display panel for reading an image displayed on the liquid crystal display panel. And a polarizing plate.

[0012]

According to the liquid crystal display device of the present invention, in the case of performing a normal image display, a pair of polarizing plates are provided outside a liquid crystal display panel including a pair of transparent electrode substrates enclosing liquid crystal and a sealing member. Use it in the placed state.

When displaying an image whose content is not known to a third party, one polarizing plate is removed from the arrangement position outside the liquid crystal display panel. Then, the user prepares a polarizing plate for reading the image displayed on the display screen of the liquid crystal display device. Examples of the polarizing plate include a polarizing plate removed from the arrangement position facing the liquid crystal display panel as described above, or another polarizing plate. As another polarizing plate, a form that is easy for a user to use, for example, a pair of glasses is used. The polarizing plate is oriented so as to maintain a predetermined relative polarization angle with respect to the polarizing plate arranged from the arrangement position facing the transparent electrode substrate. In addition, a voltage is applied to the nematic liquid crystal.

Then, the user looking at the display from the outside of the liquid crystal display panel sees the display screen of the liquid crystal display panel through the polarizing plate. That is, a person who sees the display screen through the polarizing plate can recognize the difference in the polarization angle as the intensity of light, and therefore can read the display content. Only by passing through the polarizing plate in this way, the image can be seen and displayed on the display screen so that the displayed image can be read. When the polarizing plate is not passed, the display screen can be seen only as a cloudy surface, and the image on the display screen cannot be read. That is, unless the display screen is viewed through this polarizing plate, the difference in polarization angle cannot be recognized as the intensity of light on the display screen, and the displayed contents cannot be read.

Therefore, it is possible to freely display and view an image of a content that the third party does not want to be known, without being restricted by the existence of the third party and without being seen by the third party.
Images of private contents such as documents can be displayed in public places such as trains.

In the liquid crystal display device according to the second aspect of the present invention, in the case of performing normal image display, the polarizing plate is arranged outside the liquid crystal display panel consisting of a pair of transparent electrode substrates enclosing the liquid crystal and a sealing member. Used in the state.

In the case of displaying an image whose content is not known to a third party, one of the polarizing plates is removed from the arrangement position outside the liquid crystal display panel. Then, a polarizing plate holder is prepared, and the user rotatably holds the polarizing plate for reading the image displayed on the display screen of the liquid crystal display device on the polarizing plate holder. Examples of the polarizing plate rotatably held by the polarizing plate holder include a polarizing plate removed from the arrangement position facing the transparent electrode substrate, or another polarizing plate. As another polarizing plate, a form that is easy for a user to use, for example, a pair of glasses is used. The orientation of the polarizing plate rotatably held by the polarizing plate holder is set so as to maintain a predetermined relative polarization angle with respect to the polarizing plate arranged at the position where the liquid crystal display panel is arranged.

Then, a voltage is applied to the nematic liquid crystal. The polarizing plate rotatably arranged on the liquid crystal display panel and the polarizing plate rotatably held by the polarizing plate holder are rotated in synchronization while maintaining the predetermined relative polarization angle. In this case, since each polarizing plate maintains a predetermined relative polarization angle, an image is displayed on the display screen through the polarizing plate held by the polarizing plate holder even if each polarizing plate is rotated. It is possible to read the displayed image. The rotation speed and rotation direction of the polarizing plate can be set arbitrarily and can be changed at any time.

However, if the polarizing plate rotatably held by the polarizing plate holder is not passed, the image displayed on the display screen cannot be read. Only the user can know the rotation state of the polarizing plate, and a third party can know the polarization angle of the polarizing plate held by the polarizing plate holder with respect to the polarizing plate arranged in the liquid crystal display panel. Can not. Even if a third party views the display screen using the polarizing plate held by the polarizing plate holder, the polarizing plate held by the polarizing plate holder is
In order not to know the polarization angle with respect to the polarizing plate arranged at the position facing the transparent electrode substrate, the polarizing plate owned by a third party should be compared with the polarizing plate arranged on the liquid crystal display panel. The polarization angles cannot be adjusted, and as a result, an image is displayed on the display screen and cannot be seen, and the displayed image cannot be read.

Therefore, it is possible to freely display and view an image of contents that the third party does not want to be known, without being restricted by the existence of the third party and without being seen by the third party. According to the liquid crystal display device of the invention of claim 3, the polarizing plate rotating means is arranged in a position facing the transparent electrode substrate of the liquid crystal display panel, and the polarizing plate is held by the polarizing plate holder. By forcibly rotating the plate, the polarizing plate arranged at the arrangement position of the liquid crystal display panel and the other polarizing plate held by the polarizing plate holder can be rotated accurately in synchronization.

Therefore, it is possible to freely display and view an image of contents that the third party does not want to be known, without being restricted by the existence of the third party and without being seen by the third party. According to the liquid crystal display device of the fourth aspect of the invention, since only the first polarizing plate is arranged on the liquid crystal display panel, an image is always displayed and invisible. Then, the user who views the display from the outside of the liquid crystal display panel prepares a second polarizing plate provided separately from the liquid crystal display panel, and has a predetermined polarization angle relative to the first polarizing plate. Set the orientation so that the display screen of the liquid crystal display panel is viewed through the second polarizing plate. That is, only the one having the second polarizing plate can read the display screen of the liquid crystal display panel. Therefore, it is possible to freely display and view an image of content that the third party does not want to be known, without being restricted by the existence of the third party, and without being viewed by the third party.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention of claim 1 will be described with reference to FIGS. FIG. 3 shows the structure of the liquid crystal display device of this embodiment. The liquid crystal display device of this embodiment is applied to, for example, a display device of a desk-top electronic computer or a portable electronic computer. Further, this liquid crystal display device is a light transmission type device using a backlight as a light source.

In FIGS. 1 to 3, reference numerals 1 and 2 denote a pair of rectangular transparent electrode substrates.
The reference numeral 2 is arranged to face the back side and the front side of the liquid crystal display device with a seal member 7 sandwiched between them so as to face each other. The common electrode 3 is formed on the inner surface of one transparent electrode substrate 2, and the segment electrodes 3 are formed on the inner surface of the other transparent electrode substrate 2, respectively.
Further, on the inner surfaces of the pair of transparent electrode substrates 1 and 2, an alignment film 5 for aligning molecules of a nematic liquid crystal 8 described later,
6 is formed.

A pair of transparent electrode substrates 1 and 2 and a seal member 7
A nematic liquid crystal 8 is enclosed in the space surrounded by. The nematic liquid crystal 8 is oriented by the alignment films 5 and 6 of the pair of transparent electrode substrates 1 and 2 so that the molecular axis can be twisted at a twist angle of 90 degrees from one transparent electrode substrate to the other transparent electrode substrate. A liquid crystal display panel P is configured by the pair of transparent electrode substrates 1 and 2, the seal member 7, and the liquid crystal 8.

A polarizing plate 9 is arranged outside the transparent electrode substrate 1 located on the back side of the liquid crystal display panel P so as to face the transparent electrode substrate 1, and outside the transparent electrode substrate 2 located on the front side. Is a polarizing plate 10 facing the transparent electrode substrate 2.
Is arranged. The pair of polarizing plates 9 and 10 are rectangular in shape and have the same size as the transparent electrode substrates 1 and 2, and are arranged so that the polarization angles thereof are different by 90 degrees.

In the figure, 11 is a device case, and the device case 11 accommodates and holds a liquid crystal display panel P consisting of a pair of transparent electrode substrates 1 and 2, a sealing member 7 and a liquid crystal 8 and a pair of polarizing plates 9 and 10. Has been done. Portions of the side surface of the device case 11 facing the pair of polarizing plates 9 and 10 are open.

A portion of the peripheral portion of the device case 11 facing the peripheral portion of the polarizing plate 10 is opened to form an inlet / outlet port 12, and the polarizing plate 10 is inserted into or removed from the inside of the device case 11 through the inlet / outlet port 12. It is possible. That is, the polarizing plate 10 is provided so that it can be taken in and out with respect to the arrangement position.

The operation of the liquid crystal display device thus configured will be described. When the image is not displayed (see FIGS. 2 and 3), the polarizing plate 10 is not removed from the device case 11, that is, it is not removed from the arrangement position. Further, no voltage is applied to the electrodes 3 and 4 of the pair of transparent electrode substrates 1 and 2.

Light R1 from the back side of the liquid crystal display panel P is polarized by the polarizing plate 9 into light R2 in one direction, and the transparent electrode substrate 1
And is incident on the nematic liquid crystal 8. Here, the polarizing plate will be described. 360 as shown in FIG.
When the light R1 that is a natural light having a polarization plane of 10 degrees enters the polarizing plate 9, only the polarization plane along the polarization axis of the polarizing plate 9 is transmitted and the other polarization planes are not transmitted. Therefore, the light transmitted through the polarizing plate becomes the polarized light R2 having the polarization angle in the same direction as the polarization axis of the polarizing plate.

The light incident on the nematic liquid crystal 8 is rotated by the nematic liquid crystal 8 whose molecular axis is twisted by 90 degrees.
After rotating by 90 degrees, it reaches the polarizing plate 10 whose polarization angle is shifted by 90 degrees with respect to the polarizing plate 9. At this time, the direction of light and the polarization angle of the polarizing plate 10 match. Therefore, the light passes through the polarizing plate 10 and is recognized as white by the eyes of the user.

Next, in the case of displaying an image of contents that the third party does not want to be known (see FIGS. 1 and 3), the polarizing plate 10 which can be removed from the device case 11 is removed from the device case 11. It is taken out through the outlet / inlet 12. That is, the polarizing plate 10 is removed from the arrangement position facing the transparent electrode substrate 2. Thus, by viewing the display screen (transparent electrode substrate 2) of the liquid crystal display panel P from the outside of the liquid crystal display panel P using the polarizing plate, it is possible to recognize the display of the image on the display screen and read the contents. Becomes

Then, the user prepares a polarizing plate for reading the image displayed on the display screen of the liquid crystal display panel P. Examples of this polarizing plate include a polarizing plate removed from the arrangement position facing the transparent electrode substrate of the liquid crystal display panel P, or another polarizing plate. As another polarizing plate, a form that is easy for a user to use, for example, a pair of glasses is used. In this embodiment, the polarizing plate 10 removed from the arrangement position facing the transparent electrode substrate of the liquid crystal display panel P is used. The polarization plate 10 is oriented so as to maintain a predetermined relative polarization angle of 90 degrees with respect to the polarization plate 9 arranged from the arrangement position facing the transparent electrode substrate 2. The polarizing plate 10 is held by the user directly by hand, or a dedicated polarizing plate holder is prepared and held. In this embodiment, it is assumed that the user holds the polarizing plate 10 by hand.

A user who wants to see an image from the outside of the liquid crystal display panel P looks at the display screen of the liquid crystal display panel P through the polarizing plate 10. Here, a voltage is applied to the electrodes 3 and 4 of the pair of transparent electrode substrates 1 and 2 of the liquid crystal display panel. Then, the nematic liquid crystal 8 of the liquid crystal display panel has its molecular axes aligned in the direction of the electric field from the twisted state of 90 degrees. Therefore, the light R from the back side of the liquid crystal display device
1 is polarized by the polarizing plate 9 into light in one direction, and the transparent electrode substrate 1
When the light is transmitted to the nematic liquid crystal 8 and is incident on the nematic liquid crystal 8, the nematic liquid crystal 8 is transmitted with the same polarization angle and is transmitted through the transparent electrode substrate 2. Then, the light exits the liquid crystal display panel P and reaches the polarizing plate 10 held by the user. The polarization plate 10 has a polarization angle in the same direction as the polarization angle of the light polarized by the polarization plate 9. For this reason, light cannot pass through the polarizing plate 10, and a portion where this light cannot pass is perceived as black by the user. This allows the user to see the image.

Therefore, a person who looks at the display screen through this polarizing plate can recognize the difference in the polarization angle as the intensity of light and therefore can read the displayed contents. Only by passing through the polarizing plate in this way, the image can be seen and displayed on the display screen so that the displayed image can be read. When the polarizing plate is not passed, the display screen can be seen only as a cloudy surface, and the image on the display screen cannot be read. That is, unless the display screen is viewed through this polarizing plate, the difference in polarization angle cannot be recognized as the intensity of light on the display screen, and the displayed contents cannot be read.

That is, the liquid crystal display device expresses the light and shade of the pixels of the image by the difference in the polarization angle, and the polarizing plate visualizes the difference in the polarization angle as the light and shade so that it can be recognized by human eyes. Therefore, the human eyes cannot recognize the difference in polarization angle unless a pair of polarizing plates are provided with the liquid crystal display panel sandwiched therebetween. That is, even if a light source whose polarization angle is shifted by 90 degrees is seen, the difference cannot be recognized, and if one of the polarizing plates is missing, the entire image display surface only looks white.

Therefore, it is possible to freely display and view an image of contents that the third party does not want to know, without being restricted by the existence of the third party and without being seen by the third party.
Images of private contents such as documents can be displayed in public places such as trains.

In the case of performing normal image display, the display is performed without removing the polarizing plate 10 from the device case 11. The liquid crystal display device is not limited to the display device of the desk-top electronic computer or the portable electronic computer of the above-described embodiment, but can be applied to a display device of a larger electronic computer.

Further, when an image is viewed using a polarizing plate removed from a liquid crystal display panel of a display device of a large computer, it is convenient to install a holder for holding the polarizing plate on the front side of the liquid crystal display device. is there.

In this embodiment, the front polarizing plate 10 is used.
Is detachably provided, but is not limited to this,
The polarizing plate 9 on the back side may be detachably provided, or both the polarizing plates 9 and 10 may be detachably provided and either one may be detached as necessary.

An embodiment of the invention of claim 2 will be described with reference to FIGS. The embodiment of the present invention is a modification of the liquid crystal display device according to the embodiment of the present invention. In FIGS. 4 to 6, the same parts as those of FIGS. 1 to 3 are designated by the same reference numerals. . That is, 1 and 2 are a pair of transparent electrode substrates, 3 and 4 are electrodes, 5 and 6 are alignment films,
Reference numeral 7 is a seal member, and 8 is a nematic liquid crystal, and these components constitute a liquid crystal display panel P.

Reference numerals 21 and 22 denote polarizing plates arranged outside the pair of transparent electrode substrates 1 and 2 on the back side and the front side of the liquid crystal display device. The pair of polarizing plates 21 and 22 are transparent electrode substrates 1 and 2. It has a larger round shape.

Reference numeral 23 is a device case, and this device case 23
The liquid crystal display panel P and the polarizing plates 21 and 22 are held by. One of the polarizing plates, for example, the polarizing plate 21 on the back side is supported by, for example, balls 24 and is rotatably held.
That is, the polarizing plate 21 is rotatably provided on a plane along the transparent electrode substrate 1. The other polarizing plate, for example, the polarizing plate 22 on the front side, is provided with an inlet / outlet port 2 formed in a device case
5 holds the device case 23 so that it can be taken in and out.

The operation of the liquid crystal display device thus configured will be described. When the image is not displayed and when the normal image is displayed (see FIGS. 5 and 6), the polarization angles of the polarizing plates 21 and 22 are relatively 90% without removing the polarizing plate 22. Set the orientation differently.

When displaying an image whose content is not desired to be known to a third party (see FIGS. 4 to 6), the polarizing plate 22 is taken out from the device case 23 through the inlet / outlet opening 25. That is, the polarizing plate 22 is removed from the arrangement position facing the transparent electrode substrate 2. In this state, by viewing the display screen (transparent electrode substrate 2) of the liquid crystal display panel P from the outside of the liquid crystal display panel P using a polarizing plate, it is possible to recognize the display of the image on the display screen and read the contents. It becomes a state.

Then, the user prepares a polarizing plate for reading the image displayed on the display screen of the liquid crystal display panel P. Examples of this polarizing plate include the polarizing plate 22 removed from the device case 23, or another polarizing plate. As another polarizing plate, a form that is easy for a user to use, for example, a pair of glasses is used. In this embodiment, the polarizing plate 22 removed from the arrangement position facing the transparent electrode substrate of the liquid crystal display panel P is used. The polarizing plate 22 has a predetermined relative polarization angle 9 with respect to the polarizing plate 21 held in the device case 23.
Set the orientation to maintain 0 degrees. In this embodiment, as shown in FIG. 6, the polarizing plate 22 is rotatably held by using balls 27 of a dedicated polarizing plate holder 26 prepared in advance.

A user who wants to see an image from the outside of the liquid crystal display panel P, the polarizing plate 2 held by the polarizing plate holder 26.
See the display screen of the liquid crystal display panel P through 2. on the other hand,
A voltage is applied to the electrodes 3 and 4 of the pair of transparent electrode substrates 1 and 2 of the liquid crystal display panel P. Then, the nematic liquid crystal 8 of the liquid crystal display panel P has its molecular axes aligned in the direction of the electric field from the twisted state of 90 degrees. Therefore, the light R1 from the back side of the liquid crystal display device is polarized by the polarizing plate 21 into light in one direction, passes through the transparent electrode substrate 1, and passes through the nematic liquid crystal 8
Incident on the nematic liquid crystal 8 with the same polarization angle.
Through the transparent electrode substrate 2.

Next, the light exits the liquid crystal display panel P and reaches the polarizing plate 22 held by the polarizing plate holder 26. Polarizing plate 2
Reference numeral 2 has a polarization angle in the same direction as the polarization angle of the light polarized by the polarizing plate 9. For this reason, light cannot pass through the polarizing plate 22, and a portion where this light cannot pass is perceived as black by the user. This allows the user to see the image through the polarizing plate 22.

Here, the polarizing plate 21 rotatably arranged on the liquid crystal display panel P and the polarizing plate 22 rotatably held by the polarizing plate holder 26 maintain the predetermined relative polarization angle. While synchronizing, rotate in the same direction. Since the polarizing plates 21 and 22 maintain a predetermined relative polarization angle, even if the polarizing plates 21 and 22 are rotated, the polarizing plate 2
The image can be viewed and displayed on the display screen through 2, and the displayed image can be read. The rotation speed of the polarizing plate can be set arbitrarily, and the rotation speed may be changed at any time.

The image displayed on the display screen cannot be read without passing through the polarizing plate. Only the user can know the rotation state of the polarization plates 21 and 22, and the polarization angle of the polarization plate 22 held by the polarization plate holder 26 with respect to the polarization plate 21 arranged in the liquid crystal display panel P is the first. The three cannot know. Even if a third person views the display screen using the polarizing plate, the liquid crystal display panel P of the polarizing plate 22 is used.
In order not to know the polarization angle with respect to the polarizing plate 21 arranged in the liquid crystal display panel P, the polarization angle of the polarizing plate with which the third party owns is compared with that of the polarizing plates 21 and 22 arranged in the liquid crystal display panel P. As a result, the image is displayed on the display screen as a result and cannot be seen, and the displayed image cannot be read.

Further, by changing the rotation speeds of the polarizing plates 21 and 22 at any time, it becomes difficult for a third party to adjust the polarizing angles of the polarizing plates that they own. Therefore, only when the user passes the polarizing plate 22 held by the polarizing plate holder 26, the image can be displayed and read on the display screen of the liquid crystal display panel P and can be read. When the polarizing plate 22 is not passed, the display screen can be seen only as a white turbid surface, and the image displayed on the display screen cannot be read. Therefore, it is possible to freely display and view an image of content that the third party does not want to be known, without being restricted by the existence of the third party, and without being viewed by the third party.

In this embodiment, the polarizing plate 21 is rotatably provided and the polarizing plate 22 is removable, but the present invention is not limited to this, and the polarizing plate 22 can be rotated and the polarizing plate 21 can be removed. It may be provided, or both the polarizing plate 21 and the polarizing plate 22 may be rotatably and detachably provided.

An embodiment of the invention of claim 3 will be described with reference to FIG. The liquid crystal display device of this embodiment is a polarizing plate for rotating a polarizing plate arranged on the liquid crystal display panel P in the invention of claim 2 and a polarizing plate used by a user to view a display image in synchronization with each other. The rotating means is provided. 7, the same parts as those in FIGS. 4 to 6 are designated by the same reference numerals.

In FIG. 7, 31 is a pulse motor for rotating the polarizing plate 21 rotatably held in the device case 23 of the liquid crystal display panel P, 32 is a motor driver for driving the pulse motor 31, 33 is a control unit, and 34 is 34. It is a light emitting unit that emits infrared rays.

Reference numeral 35 denotes a polarizing plate holder, and 36 denotes a circular polarizing plate exclusively used by the user to view an image.
Two of the polarizing plates 36 are provided for human eyes.
The polarizing plate rotating means for rotating the polarizing plate 21 of the liquid crystal display panel P and the polarizing plate 36 of the polarizing plate holder 35 is constituted by the components described below. That is, 37 is two annular gears to which two polarizing plates 36 are attached, which are rotatably provided in the polarizing plate holder 35 according to the distance between the eyes of the user, 38 is a pulse motor, 39 is a motor 38. Of the gears for transmitting the rotation of the above to the two polarizing plates 36, 40 a motor driver for driving the pulse motor 38, 41 a control unit,
Reference numeral 42 denotes a light receiving unit that receives the infrared light from the light emitting unit 34.

Then, in the case of displaying an image of contents that the third party does not want to be known, when the user operates the operation switch (not shown) to the control unit 33 on the device case 23 side, and inputs a drive signal, The control unit 33 is the motor driver 32.
To drive the pulse motor 31, and the motor driver 3
2 drives the pulse motor 31 to rotate. The pulse motor 31 rotates the polarizing plate 21. Although not shown, for example, the polarizing plate 21 is supported by an annular gear rotatably provided in the device case 23, and the rotation of the pulse motor 31 is transmitted to the annular gear to rotate the polarizing plate 21.

On the other hand, the control unit 33 gives a command to the light emitting unit 34, and the light emitting unit 34 emits infrared rays toward the light receiving unit 42 of the polarizing plate holder 35. The polarizing plate holder 35 is, for example, of a goggle type, and a user can wear it on his / her head in the same manner as glasses. When the light receiving unit 42 receives infrared rays, the control unit 41 commands the motor driver 40 to drive the motor, and the motor driver 40 rotationally drives the pulse motor 38. The pulse motor 38 rotates the pair of annular gears 37 via the gear 39, and the pair of polarizing plates 36 rotates together with the pair of annular gears 37.

The two polarizing plates 36 of the polarizing plate holder 35 and the polarizing plate 21 of the device case 23 rotate synchronously in the same direction while maintaining a relationship having a polarization angle of 90 degrees, for example. Therefore, as in the case of the embodiment of the invention of claim 3, only the user who rotates the polarizing plate 36 of the polarizing plate holder 35 can see the image displayed on the liquid crystal display panel P.

According to the liquid crystal display device of the present invention, the polarizing plate rotating means and the polarizing plate 21 arranged at the arrangement position facing the transparent electrode substrate of the liquid crystal display panel P and the user viewing the display image. By forcibly rotating the polarizing plate 36 held by the polarizing plate holder 35 used for the above, the polarizing plate 21 arranged on the liquid crystal display panel P and the polarizing plate held by the polarizing plate holder 35 are used. 47 can be rotated in exact synchronization. Therefore, it is possible to freely display and view an image of content that the third party does not want to be known, without being restricted by the existence of the third party, and without being viewed by the third party.

An embodiment of the invention of claim 4 will be described with reference to FIGS. 8 and 9. In the liquid crystal display device according to the invention of claim 4, the first polarizing plate is arranged outside one transparent electrode substrate of the pair of transparent electrode substrates in the liquid crystal display panel P, and the second polarizing plate serves as the liquid crystal display panel. This is a system separately provided and used for viewing an image displayed on the liquid crystal display panel P.

A first embodiment of the invention of claim 4 will be described with reference to FIG. In FIG. 8, 1 and 2 are a pair of transparent electrode substrates, 3 and 4 are electrodes, 5 and 6 are alignment films, 7 is a sealing member, and 8 is a nematic liquid crystal, and these components constitute a liquid crystal display panel P. . In this liquid crystal display panel P, only the first polarizing plate 61 of the pair of polarizing plates 61, 62 necessary for viewing the image is arranged, so that the image is always displayed and invisible.

63 is a device case, and this device case 63
The liquid crystal display panel P and the first polarizing plate 61 are held in the. The first polarizing plate 61 has the same size and shape as the transparent electrode substrates 1 and 2, and is arranged, for example, outside the transparent electrode substrate 1 on the back side of the pair of transparent electrode substrates 1 and 2. 62 is a second polarizing plate, which is a liquid crystal display panel P
It is provided independently of, and the user uses the image of the liquid crystal display panel P.

Then, the user can read the image displayed on the display screen of the liquid crystal display panel P by reading the second polarizing plate 6
2 is prepared, and the second polarizing plate 62 is a liquid crystal display panel P.
The orientation is set so as to maintain a predetermined relative polarization angle of 90 degrees with respect to the first polarizing plate 61 provided in. The polarizing plate 62 is directly held by the user, or a dedicated polarizing plate holder is prepared and held. In this embodiment, it is assumed that the user holds the polarizing plate 62 by hand. And
A user who wants to see an image from the outside of the liquid crystal display panel P views the display screen of the liquid crystal display panel P through the polarizing plate 62. This allows the user to see the image displayed on the liquid crystal display panel P.

That is, only the one having the second polarizing plate 62 can read the display screen of the liquid crystal display panel P. Therefore, it is possible to freely display and view an image of content that the third party does not want to be known, without being restricted by the existence of the third party, and without being viewed by the third party.

FIG. 9 shows another embodiment of claim 4. In this embodiment, the same parts as those in FIG. 8 are designated by the same reference numerals. In FIG. 9, reference numeral 71 denotes a first polarizing plate, which has a larger circular shape than the transparent electrode substrates 1 and 2. The first polarizing plate 71 is arranged, for example, outside the transparent electrode substrate 1 on the back side in the device case 73, supported by the balls 24, and rotatably held. 72 is a second polarizing plate, which has the same size and shape as the first polarizing plate 71. The second polarizing plate 72 is provided independently of the liquid crystal display panel P, and the user uses the image on the liquid crystal display panel P. The second polarizing plate 72 includes a polarizing plate holder 74 and balls 7
It is rotatably held by using 5.

Then, a user who wants to see an image from the outside of the liquid crystal display panel P prepares the second polarizing plate 72 to read the image displayed on the display screen of the liquid crystal display panel P, and The first polarizing plate 21 that is rotatably arranged on the liquid crystal display panel P by rotating the polarizing plate 72 and the polarizing plate 72 that is rotatably held by the polarizing plate holder 26 have a predetermined relative polarization angle. Rotate in the same direction synchronously while maintaining. The user views the display screen of the liquid crystal display panel P through the polarizing plate 72.

As a result, the user can see the image displayed on the liquid crystal display panel P. That is, only the one having the second polarizing plate 72 can read the display screen of the liquid crystal display panel P. Therefore, it is possible to freely display and view an image of content that the third party does not want to be known, without being restricted by the existence of the third party, and without being viewed by the third party.

The present invention is not limited to the above-described embodiments, but can be modified in various ways. In the embodiments of the above claims, the TN type liquid crystal display device using the nematic liquid crystal is targeted, but in order to reduce the crosstalk of the image, the twist angle is set to 180 degrees or more to improve the steepness. A liquid crystal display device using STN (Super Twisted Nematic) type liquid crystal can be targeted. The liquid crystal driving method may be a simple matrix or an active matrix. The liquid crystal display device may be a backlight type or a reflection type.

[0068]

According to the liquid crystal display device of the present invention, at least one of the pair of polarizing plates rotatably provided outside the pair of transparent electrode substrates can be removed by the polarizing plate rotating means. Since it is provided, when displaying an image of contents that you do not want to be known to a third party, remove one polarizing plate from the outside of the unit and prepare a polarizing plate to see the displayed image. By looking at the display screen through the plate, the user can see and see the image on the display screen only by passing through the polarizing plate. When the polarizing plate is not passed, the display screen can be seen only as a cloudy surface, and the image on the display screen cannot be read.

Therefore, it is possible to freely display and view an image of contents that the third party does not want to be known, without being restricted by the existence of the third party and without being seen by the third party.
Images of private contents can be displayed even in public places such as on a train.

According to the liquid crystal display device of the invention of claim 2,
When displaying an image of content that you do not want others to know,
The polarizing plate is held only by rotating the polarizing plate arranged outside the transparent electrode substrate and the polarizing plate held by the polarizing plate holder in synchronization while maintaining the predetermined relative polarization angle. An image is displayed on the display screen through the polarizing plate held by the body so that the displayed image can be read and read.

Only the user can know the rotating state of the polarizing plate, and the polarization angle of the polarizing plate held by the polarizing plate holder with respect to the polarizing plate arranged on the liquid crystal display panel can be determined by a third party. I can't know. Even if a third party views the display screen using the polarizing plate held by the polarizing plate holder, the polarizing plate held by the polarizing plate holder is arranged at the position facing the transparent electrode substrate. Since the third party does not know the polarization angle with respect to the polarizing plate, it is not possible for the third party to match the polarization angle with the polarizing plate arranged on the liquid crystal display panel. In, the image is displayed and cannot be seen, and the displayed image cannot be read.

Therefore, it is possible to freely display and view an image of a content that the third party does not want to be known, without being restricted by the existence of the third party and without being seen by the third party.
Images of private contents can be displayed even in public places such as on a train.

According to the liquid crystal display device of the third aspect,
The polarizing plate rotating means is arranged on the liquid crystal display panel by forcibly rotating the polarizing plate arranged at the arrangement position facing the transparent electrode substrate and the polarizing plate held by the polarizing plate holder. The polarizing plate held by the polarizing plate and the polarizing plate held by the polarizing plate holder can be precisely synchronized to rotate, and an image with private contents can be displayed even in a public place such as in a train.

Therefore, it is possible to freely display and view an image of contents that the third party does not want to be known, without being restricted by the existence of the third party and without being seen by the third party. According to the liquid crystal display device of the fourth aspect of the invention, since only the first polarizing plate is arranged on the liquid crystal display panel, an image is always displayed and invisible. Then, the user who views the display from the outside of the liquid crystal display panel prepares a second polarizing plate provided separately from the liquid crystal display panel, and has a predetermined polarization angle relative to the first polarizing plate. Set the orientation so that the display screen of the liquid crystal display panel is viewed through the second polarizing plate. That is, only the one having the second polarizing plate can read the display screen of the liquid crystal display panel. For this reason, it is possible to freely display and view images of contents that the third party does not want to be known, without being restricted by the existence of the third party, and without being seen by the third party.
Images of private contents can be displayed even in public places such as on a train.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a voltage application state of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a state in which no voltage is applied to the liquid crystal display device in the example.

FIG. 3 is a cross-sectional view showing a liquid crystal display device in the example.

FIG. 4 is a perspective view schematically showing a voltage application state of the liquid crystal display device according to the embodiment of the invention of claim 2.

FIG. 5 is a perspective view schematically showing a voltage non-applied state of the liquid crystal display device in the example.

FIG. 6 is a cross-sectional view showing a liquid crystal display device in the example.

FIG. 7 is a sectional view showing a liquid crystal display device according to an embodiment of the invention of claim 3;

FIG. 8 is a sectional view showing a liquid crystal display device according to an embodiment of the invention of claim 4.

FIG. 9 is a sectional view showing a liquid crystal display device according to another embodiment of the invention of claim 4.

FIG. 10 is an explanatory diagram showing light transmission in a liquid crystal display device.

[Explanation of symbols]

1 ... Transparent electrode substrate, 2 ... Transparent electrode substrate,
8 ... Nematic liquid crystal, 9 ... Polarizing plate, 10 ...
Polarizer, 11 ... Device case, 13 ...
Holding member, 21 ... Polarizing plate, 22 ... Polarizing plate, 23 ... Device case, 26 ... Holding member, 31 ... Pulse motor, 38 ... Pulse motor, 51 ... Pulse motor, P ... Liquid crystal display panel.

Claims (4)

[Claims] 1. A pair of transparent electrode substrates provided so as to face each other and spaced apart from each other, a nematic liquid crystal enclosed between the pair of transparent electrode substrates with a predetermined twist angle, and a pair of transparent electrode substrates facing each other outside the pair of transparent electrode substrates. A liquid crystal display device comprising: a pair of polarizing plates, which are arranged with a predetermined polarization angle and at least one of which is removable from the arranged position. 2. A pair of transparent electrode substrates provided facing each other and spaced apart from each other, a nematic liquid crystal enclosed between the pair of transparent electrode substrates with a predetermined twist angle, and relatively to the outside of the pair of transparent electrode substrates. A liquid crystal display panel having a pair of polarizing plates arranged with a predetermined polarization angle, one of which is rotatable on a plane parallel to the transparent electrode substrate and the other of which is detachable with respect to its arranged position; A liquid crystal display device comprising: a polarizing plate for reading an image displayed on a display panel; and a polarizing plate holder for rotatably holding the polarizing plate. 3. The polarizing plate rotating means for driving the polarizing plate arranged at the arrangement position and the polarizing plate held by the polarizing plate holder in synchronization with each other. Liquid crystal display device. 4. A pair of transparent electrode substrates provided facing each other, a nematic liquid crystal enclosed between the pair of transparent electrode substrates with a predetermined twist angle, and one transparent electrode of the pair of transparent electrode substrates. A liquid crystal display panel having a first polarizing plate disposed outside the substrate; and a second polarizing plate provided separately from the liquid crystal display panel for reading an image displayed on the liquid crystal display panel. Characteristic liquid crystal display device.