JP2006072239A - Display device and polarizing body, and view angle controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a display device that can maintain display quality using simple constitution and conceal a display image in a prescribed direction using mode switching, by making another image overlap the display image. <P>SOLUTION: The display device 4 is equipped with a main LCD 14, an SW-LCD 12 which is arranged in the optical path of light transmitted through the main LCD 14 for electrically switching over a viewed image, between a single image display mode and a multiple-image display mode; a 1st polarizer 13, and a 2nd polarizer 11 having a polarization region where, a linearly polarized light in the same direction as with the 1st polarizer is extracted from light projected from a display switching over means and a transmission region where the light projected from the display switching means is transmitted, as it is. The alignment directions of the liquid crystal molecules of a liquid crystal layer 23 of the SW-LCD 12 are so controlled that long-axis directions, when light is projected from at right angles to substrates 21 and 22 are always substantially parallel to the polarizing direction of the light, having been transmitted through the 1st polarizer, and the long-axis directions of the liquid crystal molecules are nearly parallel to the substrates in the single image display mode and oblique with respect to the substrates in the multiple-image display mode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device, and more particularly, to a display device that can be switched to a mode in which an image viewed according to the line-of-sight direction changes.

  In recent years, electronic devices have been made lighter, and electronic devices having a display such as mobile phones and mobile personal computers can be taken out and used in public places. In this case, there has been a problem that confidential documents and information to be personally viewed can be seen by people nearby.

  In response to this problem, a method of displaying a narrow viewing angle by pasting a privacy film (for example, 3M, security privacy film) on a screen is known. In the narrow viewing angle display, a normal display image can be visually recognized from directly in front of the display where the user is present, and a plain image or another image is visually recognized from an oblique direction. However, if such a privacy film is pasted, the privacy film must be peeled off when a wide viewing angle is required, such as when displaying a photographed image on a mobile phone and viewing it by a large number of people. Don't be. In other words, in order to switch between a narrow viewing angle and a wide viewing angle, it is necessary to affix or peel off a polarizing film, which is cumbersome for the user and has a problem that the privacy film is lost or difficult to affix. .

  Therefore, a method of switching between a narrow viewing angle and a wide viewing angle with a switch or the like has been proposed.

  For this purpose, for example, in the viewing angle variable element disclosed in Patent Document 1, a liquid crystal layer between a pair of substrates has a narrow viewing angle by aligning liquid crystal molecules in a direction perpendicular to the substrates, and a parallel direction. A wide viewing angle is obtained by orienting the film. Patent Document 2 describes a viewing angle changing means for changing the viewing angle of the information display means by changing the orientation of the liquid crystal between two glass plates.

In addition, by dividing the display device into several sections and changing the liquid crystal alignment direction etc. in each section, what is displayed on the display when viewing the display from a direction other than the front in the narrow viewing angle mode There is also a configuration in which another image different from that is visible. For example, Patent Document 3 discloses a liquid crystal display device in which an alignment film sandwiching a liquid crystal layer is partitioned into a plurality of regions, and the alignment directions of adjacent regions are different. Patent Document 4 discloses a liquid crystal display device in which first liquid crystal cells and second liquid crystal cells having different viewing angle directions are alternately arranged.
JP-A-9-105958 (release date: April 22, 1997) JP 2004-62094 (release date: February 26, 2004) JP 2001-264768 (release date: September 26, 2001) JP-A-2004-38035 (Release date: February 5, 2004)

  However, in the configuration of Patent Document 1 described above, the refractive index is changed by vertically aligning liquid crystal molecules to form a narrow viewing angle mode. However, the viewing angle control using such a refractive index improves the display quality of an image. Difficult to keep. Further, there is no description of a method for displaying a fixed pattern when viewed from a direction other than the front direction in the narrow viewing angle mode.

  Patent Document 2 describes that the viewing angle of the display is controlled by changing the orientation of the liquid crystal, but does not describe how to change the orientation of the liquid crystal. Control cannot be realized. Further, there is no description of a method for displaying a fixed pattern when viewed from a direction other than the front direction in the narrow viewing angle mode.

  Furthermore, although the configuration of Patent Document 3 describes that a fixed pattern unrelated to the display signal is visually recognized from directions other than the front direction, it is structurally viewed from the right direction and the pattern viewed from the right direction. Since the monochrome pattern is reversed from the viewed pattern, the display image cannot be properly hidden when viewed from a direction other than the front direction. In other words, if the non-transparent area is increased when viewed from the right direction, the transmissive area increases when viewed from the left direction. It can only be made difficult to see by covering an image like a houndstooth with half the area.

  In addition, the configuration of Patent Document 4 is a configuration in which a large number of small liquid crystal cells are arranged in an array plate, but such a liquid crystal display device has a complicated configuration and is difficult to manufacture.

  As described above, there is no known display device with a simple configuration that has a high display quality and can switch modes so that a display image can be appropriately hidden from an oblique line of sight.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a display device that can maintain display quality with a simple configuration and can hide a display image from a specific direction by mode switching. Is to realize.

  In order to solve the above problems, a display device according to the present invention includes a video display means for displaying and outputting an image, an optical path of light incident on the video display means, or a light emitted from the video display means. Display switching means for electrically switching an image that is arranged and viewed in the optical path between a single image display mode and a multi-image display mode, and a first light path that is arranged on a path of light incident on the display switching means A polarizing means, and a second polarizing means disposed in a path of light emitted from the display switching means, wherein the display switching means includes a pair of substrates and a liquid crystal layer disposed between the substrates. The major axis direction when the liquid crystal molecules of the liquid crystal layer are projected from a direction orthogonal to the substrate and the linear polarization direction of the light incident on the liquid crystal molecules are always substantially parallel or substantially perpendicular. The liquid crystal molecule is a single image display module. In the multi-image display mode, the major axis direction of the liquid crystal molecules is aligned so that the major axis direction of the liquid crystal molecules is substantially parallel or substantially perpendicular to the substrate. Further, at least one of the first polarizing means and the second polarizing means is provided with a transmission region having a polarization degree different from that of the polarization region.

  Here, the inclination means that it is neither parallel nor perpendicular to a certain direction or a certain plane.

  For example, the major axis direction of the liquid crystal molecules of the liquid crystal element is included in a plane formed by the direction of the transmission axis or absorption axis of the first polarizing means and the traveling direction of light, and the liquid crystal molecules This is a configuration that can take a state where the direction is substantially perpendicular or substantially parallel to the light traveling direction and a state inclined with respect to the light traveling direction.

  In other words, in the single image display mode, the major axis direction of the liquid crystal molecules of the liquid crystal layer is substantially parallel to the substrate and substantially parallel to or substantially perpendicular to the polarization transmission axis of the first polarizing means, so that a plurality of images are displayed. In the mode, the single image display mode is inclined in a plane perpendicular to the substrate. Alternatively, the major axis direction of the liquid crystal molecules of the liquid crystal layer is substantially perpendicular to the substrate in the single image display mode, and from the state of the single image display mode in the multiple image display mode, It is inclined with respect to the substrate in a plane substantially parallel or substantially perpendicular to the polarization transmission axis and perpendicular to the substrate.

  According to this, the light incident on the display switching unit becomes linearly polarized light in a certain direction by the first polarizing unit. Further, in the liquid crystal layer of the display switching means, the major axis direction when the liquid crystal molecules are projected from the direction orthogonal to the substrate (normal direction of the main surface of the substrate) is transmitted through the first polarizing means and incident on the liquid crystal molecules. The light is oriented so that it is always substantially parallel or substantially perpendicular to the polarization direction of the light.

  When the polarization direction of linearly polarized light incident on the liquid crystal layer and the major axis direction when liquid crystal molecules are projected from a certain direction are parallel or perpendicular, birefringence does not occur in the liquid crystal layer when viewed from this direction. . Therefore, not limited to the selected mode, birefringence does not always occur in the liquid crystal layer viewed from the line of sight parallel to the plane drawn by the dots on the liquid crystal molecules due to orientation changes (hereinafter referred to as “line of sight in the front direction”). .

  Thus, for example, the polarization transmission axes of the first polarization means and the polarization areas of the second polarization means are set in the same direction, or the linearly polarized light emitted from the first polarization means is changed to the polarization transmission axis of the polarization area of the second polarization means. If the linearly polarized light in the same direction as the first polarizing means is extracted by the second polarizing means by rotating the polarization direction so as to coincide with the second polarizing means, the polarizing area and the transmission area The light intensity will be different. Thereby, for example, if a specific pattern is formed by the transmissive region, the specific pattern can be obtained when viewed from a direction other than the front direction (hereinafter referred to as viewed from an oblique direction) in the multiple image display mode. Can be recognized.

  Alternatively, the linear polarization direction of the light incident on the liquid crystal molecules as the display switching means and the polarization transmission axis of the polarization region of the second polarization means are made the same direction, or the linear polarization incident on the liquid crystal molecules is changed to the second polarization means. By installing a member that rotates the polarization direction so as to coincide with the polarization transmission axis of the polarization region and enters the second polarization means, linear polarization in the same direction as the linear polarization incident on the liquid crystal molecules is provided in the second polarization means. If the light is extracted at, the light intensity differs between the polarization region and the transmission region. Thereby, for example, if a specific pattern is formed by the transmissive region, the specific pattern can be recognized when viewed from the oblique direction other than the front direction in the multiple image display mode. .

  The transmission region can be formed by hollowing out at least one of the first polarizing means and the second polarizing means, for example, in a predetermined pattern. In this way, it is possible to easily increase the difference in light density between the polarization region and the transmission region and increase the contrast of an image with a high specific pattern.

  As described above, when viewed from an oblique direction, the display device of the present invention has different images that are visually recognized in the single image display mode or the multiple image display mode.

  In the single image display mode, since the major axis direction of the liquid crystal molecules is substantially parallel or substantially perpendicular to the substrate, the major axis direction of the liquid crystal molecules when projected from an oblique direction is the same as when viewed from the front. become. Therefore, even when viewed from an oblique direction, birefringence does not occur in the liquid crystal molecules, and incident light passes through the liquid crystal layer and the second polarizing means regardless of the polarization region or transmission region, and the image of the video display device is visually recognized. it can.

  On the other hand, in the multi-screen display mode, since the major axis direction of the liquid crystal molecules is inclined with respect to the substrate, the major axis direction of the liquid crystal molecules when projected from an oblique direction is the polarization direction of the incident light. Has a crossing angle. Therefore, when viewed from an oblique direction, birefringence occurs in the liquid crystal molecules, and the polarization direction of the light transmitted through the liquid crystal layer changes, so that the transmitted light does not pass through the polarization region. On the other hand, in the transmission region, light is transmitted even if birefringence occurs. Therefore, the image of the video display device is visually recognized by overlapping the specific pattern formed by the polarization region and the transmission region, and the image of the video display device corresponding to the polarization region cannot be visually recognized.

  Therefore, in the single image display mode, the image displayed by the video display unit can be viewed from any direction, and in the multiple image display mode, the image displayed by the video display unit can be viewed from the front direction, and the image can be viewed from the oblique direction. An image in which the specific pattern of the polarization region overlaps the image displayed by the display means is visually recognized. Therefore, according to this display device, for example, when viewing a confidential document in a public place, as a multiple image display mode, when viewed from an oblique direction, a specific pattern is viewed instead of a confidential document. When viewing an image with a large number of people, the viewing angle can be changed according to the situation, such as a single image display mode. The shape of the specific pattern is not particularly limited, and any shape such as a logo, a character, or a pattern may be used.

  Also, the displayed logo and character will not be reversed in black and white depending on the viewing direction, and the same image will be displayed from any angle, so if you cover the black image so that it is mostly in the polarization region The image of the liquid crystal display means can be hidden well.

  Further, according to such a configuration, since the viewing angle is controlled by controlling the birefringence, the display quality of the video display device can be kept good with a simple configuration.

  Further, an image viewed from an oblique direction in the multiple image mode is determined by a pattern in which the transmission region and the polarization region are formed in the first polarization unit and / or the second polarization unit. There are three patterns for forming the polarization region: both the first polarization means and the second polarization means, only the first polarization means, and only the second polarization means. If the polarizing region is formed only on the second polarizing means and is detachable, it is possible to change the image seen from the oblique direction in the multiple image display mode by exchanging the second polarizing means.

  Note that the “major axis direction” when liquid crystal molecules are projected assumes that all directions are the major axis direction when the projection is a perfect circle.

  Further, the position where the display switching means is provided is not particularly limited, and for example, the display switching means may be arranged on the front surface or the back surface of the video display means.

  In addition, the display device of the present invention is characterized in that the transmittance of the transmission region is 0.8 times or more and 1.2 times or less of the transmittance of the polarization region.

  According to this, when light is transmitted through both the polarization region and the transmission region of the second polarization unit when viewed from the single image display mode or from the front, the image of the image display unit that is visually recognized is bright. There is no difference and it is easy to see. If the transmittance of the transmissive region is lower than 0.8 times the transmittance of the polarizing region, light transmission is less likely to occur in the portion that overlaps the transmissive region of the image display means than the portion that overlaps the polarizing region, and the image appears darker. It becomes difficult to see. On the other hand, if the transmittance of the transmission region is greater than 1.2 times the transmittance of the polarization region, the portion of the image displayed by the video display means that the portion overlapping the polarization region is less likely to transmit light than the portion overlapping the transmission region. Because it looks dark, it becomes difficult to see the image. The “transmittance” refers to the transmittance of visible light (wavelength of about 380 to 800 nanometers).

  In addition, the adjustment of the transmittance of the transmission region can be realized by adjusting the concentration of the dye in the case where the first polarizing means and / or the second polarizing means 1 includes the dye, for example. In addition, since at least one of the first polarizing means and the second polarizing means is colored by adding a dye, a colored display pattern can be displayed as an image that can be seen from an oblique direction in a multi-image mode. Will be observed. Thereby, for example, by setting the color to match the shape of the display pattern, it is possible to improve the expressive power over the display of white and black.

  The display device of the present invention is characterized in that a single image display mode is set when no voltage is applied to the liquid crystal molecules, and a multi-image display mode is set by applying a predetermined voltage to the liquid crystal molecules.

  Since it is easier to align the liquid crystal molecules parallel or perpendicular to the substrate in the absence of voltage application than inclining at a certain angle, it is preferable to set the single image display mode in the absence of application of voltage. . In addition, when the image is frequently used in the single image display mode, the power consumption is lower in the single image display mode when no voltage is applied.

  Moreover, the display apparatus of this invention is good also as a structure provided only in the said 2nd polarization means to which the said transmissive area | region is attached so that attachment or detachment is possible.

  According to this, a plurality of images can be easily and inexpensively obtained by replacing various second polarizing means having different formation regions of the polarizing area and the transmission area of the second polarizing means according to the user's preference and mood. The symbol visually recognized when viewed from the oblique direction in the display mode can be changed. In addition, in the case of a display device adopting this configuration, a user who feels that switching to the multi-image mode is not necessary is performed by simply removing the second polarizing means, so that the display is always in the single image display mode. It has the characteristic that it can be in the same state.

  In the single image display mode, the display device of the present invention can visually recognize the image displayed by the video display means from any direction. In the multiple image display mode, the polarization region is imaged by birefringence from a specific direction. It is characterized by being visually recognized by overlapping with the image of the display means.

  According to this, in the single image display mode, the image displayed by the video display means can be visually recognized from any direction, and in the multiple image mode, the display image is hidden by overlapping other images on the display image from a specific direction. A display device that can be used is realized.

  The “specific direction” is a direction other than the front direction described above.

  In this configuration, in the multiple image mode, the major axis direction when the liquid crystal molecules of the image switching means project from the direction orthogonal to the substrate and the polarization direction of the light transmitted through the first polarizing means are substantially parallel or substantially. This can be realized by controlling the alignment so that the liquid crystal molecules are inclined at right angles and the major axis direction of the liquid crystal molecules is inclined with respect to the substrate.

  The display device of the present invention is characterized in that the liquid crystal molecules are inclined in the vertical direction in the image displayed on the video display means in the multiple image display mode.

  Here, "the liquid crystal molecules are inclined in the vertical direction of the image displayed on the video display means" means that the image displayed on the video display means is upward or downward from a state perpendicular to the substrate. Means to tilt. In other words, the video display means and the display switching means are bonded so that the plane drawn by the dots on the liquid crystal molecules when the orientation changes and the vertical direction of the image displayed on the video display means are substantially parallel. ing.

  According to the above configuration, when the vertical direction of the image of the video display means is set to the vertical direction, the image of the video display means is seen from the front of the display device, and from the left and right, the image switching means and the second An image on which another image is superimposed by the polarizing means is visually recognized. Therefore, an image can be hidden from more people in a place where the line of sight is assumed to be relatively uniform.

  The multi-image display mode is characterized in that the angle formed by the major axis direction of the liquid crystal molecules and the substrate is 40 degrees or more and 50 degrees or less.

  In the image switching means, the angle formed between the major axis direction of the liquid crystal molecules and the substrate is 45 degrees, so that the major axis direction of the liquid crystal molecules when projected from an oblique direction is 45 degrees with the polarization direction of the incident light. Has a crossing angle. At this time, when viewed from an oblique direction, optimal birefringence occurs in the liquid crystal molecules, the polarization direction of the light transmitted through the liquid crystal layer changes, and the light does not pass through the second polarizing means, so that the image of the video display device is optimally hidden. .

  Therefore, in the multi-image display mode, when the angle between the major axis direction of the liquid crystal molecules and the substrate is set to 40 degrees or more and 50 degrees or less, when viewed from a specific direction, other images are good as the display image. The display image can be hidden by overlapping, and the function of changing the viewing angle according to the situation is further improved. On the other hand, when the angle between the major axis direction of the liquid crystal molecules and the substrate is out of the above range, the birefringence effect becomes lower and the image may not be sufficiently hidden.

  The polarizing body of the present invention functions as the second polarizing means of the display device and is detachably attached to the display switching means.

  Here, the polarizer may be a plate or a film. By using such a polarizer as the second polarizing means of the display device, the function described above can be imparted to the display device. Further, various polarizers having different formation regions for the polarization region and the transmission region can be attached as the second polarization means depending on the user's preference and mood. Therefore, it is possible to change the design that is visually recognized when viewed from an oblique direction in the multiple image display mode at low cost.

  The viewing angle control device of the present invention is a viewing angle control device that controls and outputs the viewing angle of incident light, and includes a liquid crystal element and a polarizing region that is provided on the liquid crystal element and extracts linearly polarized light, And a transmission region that transmits light as it is, includes a plate arranged so as to form a specific pattern and linear polarization means, and the major axis direction of the liquid crystal molecules of the liquid crystal element is the transmission of the linear polarization means The liquid crystal molecules are included in a plane formed by the direction of the axis or absorption axis and the light traveling direction, and the liquid crystal molecules are substantially perpendicular to or substantially parallel to the light traveling direction and the light traveling direction. It is characterized by being able to take an inclined state.

  By attaching such a viewing angle control device to a display device that is generally used, a display device having the above-described function is obtained.

  As described above, the display device according to the present invention is arranged in the video display means for displaying an image and the optical path of light incident on the video display means or the optical path of light emitted from the video display means. A display switching means for electrically switching a visually recognized image between a single image display mode and a multiple image display mode; a first polarizing means disposed in a path of light incident on the display switching means; and the display A second polarization unit disposed in a path of light emitted from the switching unit, and the display switching unit includes a pair of substrates and a liquid crystal layer disposed between the substrates, The major axis direction when the liquid crystal molecules of the liquid crystal layer are projected from the direction orthogonal to the substrate and the polarization direction of the light transmitted through the first polarizing means are always substantially parallel or substantially perpendicular. In single image display mode, the long axis direction of liquid crystal molecules Are aligned so that they are substantially parallel or substantially perpendicular to the substrate, and in the multiple image display mode, the long axis direction of the liquid crystal molecules is aligned with respect to the substrate, and the first polarizing means and At least one of the second polarizing means is provided with a transmission region having a polarization degree different from that of the polarization region.

  According to this, in the single image display mode, the image displayed by the video display means can be viewed from any direction, and in the multiple image mode, the image displayed by the video display means can be viewed from the front direction, and from the oblique direction. In which an image displayed by the video display means is visually recognized with a polarization region overlapping. Therefore, this display device can change the viewing angle according to the situation such as when viewing a confidential document in a public place or when viewing a captured image with a large number of people.

  Further, according to such a configuration, since the viewing angle is controlled by controlling the birefringence, the display quality of the video display device can be kept good with a simple configuration.

  Furthermore, since an image seen from an oblique direction in the multi-image mode is determined by the polarizing means provided with the transmissive area, for example, if the transmissive area is formed only on the second polarizing means detachably attached. By exchanging the second polarizing means, it is possible to change the image seen from the oblique direction in the multiple image mode.

  An embodiment of the present invention will be described below with reference to FIGS.

  FIG. 2 shows the appearance of the mobile phone 1 according to an embodiment of the present invention. The mobile phone 1 according to the present embodiment is a so-called clamshell type, and is shown in an open state in FIG. FIG. 1 shows a portion that becomes an inner side when the mobile phone 1 is closed, and a side that is mainly used by a user when the mobile phone 1 is opened. Therefore, in this application, the side shown in FIG.

  As shown in FIG. 2, the mobile phone 1 includes a main body 2 and a lid 3, and the main body 2 and the lid 3 are connected in a hinge shape. The lid 3 is provided with a display unit (display device) 4 on the front side.

  The main body 2 is provided with a main operation button group 6 on the front side. The main operation button group 6 includes a function button group 7 for performing various settings and function switching in the mobile phone 1 and an input button group 8 for inputting symbols such as numbers and letters. Specifically, the function button group 7 includes a power button for switching on / off the power of the mobile phone, a camera button for starting a shooting mode, a mail button for starting a mail mode, and moving a selection target in the vertical and horizontal directions. For example, and a determination button which is arranged at the center of the cross button and determines various selections. The input button group 8 is a numeric keypad.

  The mobile phone 1 of the present invention can display another image on the display unit 4 from the periphery when a main image such as a mail text or a photographed image is displayed on the display unit 4. Hereinafter, the setting in which the e-mail body and the photographed image cannot be seen from the surroundings is referred to as a narrow viewing angle mode (multiple image display mode), and the mode in which the display unit 4 can be viewed from any angle as usual is wide viewing. This is called a corner mode (single image display mode, normal mode). The user can arbitrarily change the setting of the narrow viewing angle mode and the wide viewing angle mode using the operation buttons.

  As shown in FIG. 3, in the wide viewing angle mode, the display unit 4 is viewed from the front (front orientation), and is also viewed from an oblique front on the right side from the front toward the display unit 4 (right side surface). (Azimuth), the main image is also visually recognized when viewed from the front obliquely to the left from the front toward the display unit 4 (left side orientation). On the other hand, in the narrow viewing angle mode, as shown in FIG. 4, the main image is visually recognized in the front direction, but from the right side direction or the left side direction, the switching image including the “SHARP” logo on the black display is displayed. Visible.

  Below, the detailed structure of this display part 4 is demonstrated.

  A cross-sectional view of the display unit 4 is shown in FIG. The display unit 4 includes a second polarizing plate (polarizing body) 11, a switching liquid crystal display unit (display switching unit, hereinafter referred to as SW-LCD) 12, a first polarizing plate 13, a main liquid crystal display unit (image display unit, hereinafter). 14 and a third polarizing plate 15 are laminated in this order, and a backlight 16 is provided on the third polarizing plate side.

  Here, the relationship between the polarization transmission axis of the first polarizing plate 13 and the polarization transmission axis of the second polarizing plate 11 is preferably set in parallel, but according to the requirements of the characteristics of the main LCD, May have any axis angle.

  In this case, the polarization direction of the linearly polarized light emitted from the first polarizing plate 13 set at an arbitrary axis angle is appropriately adjusted to match the transmission axis of the second polarizing plate 11 with a λ / 2 plate or the like. By rotating, the same effect as when the polarization transmission axis of the first polarizing plate 13 and the polarization transmission axis of the second polarizing plate 11 are set in parallel can be obtained.

  The second polarizing plate 11 is attached to the SW-LCD 12, and the first polarizing plate 13 and the third polarizing plate 15 are attached to both surfaces of the main LCD 14, and the second polarizing plate of the SW-LCD 12. The side to which 11 is not attached and the main LCD are bonded by the bonding portion 17. Here, what the 2nd polarizing plate 11 affixed on SW-LCD12 functions as a paper and a corner control apparatus. The bonding portion 17 may be bonded with a thermosetting or ultraviolet curable resin adhesive, or may be fixed with a so-called double-sided tape. Further, the pasting area may be a whole surface bonding or a partial bonding such as a frame shape.

  In the main LCD 14, a liquid crystal layer 43 is sealed between the transparent electrode substrates 41 and 42. By applying a voltage to the transparent electrode substrates 41 and 42 according to a control unit (not shown), the alignment of liquid crystal molecules in the liquid crystal layer 43 is performed. Change the to display the image. The main LCD 14 is controlled by a control unit (not shown) so as to display an operation screen of the mobile phone 1, a picture, an image such as a mail text, and the like. As the main LCD 14, a generally known liquid crystal display device may be used. For example, a liquid crystal display device of any mode such as a TN (Twisted Nematic) mode liquid crystal display device driven by an active matrix drive method or a VA (Vertical alignment) mode display type liquid crystal display device can be used. Further, instead of the main liquid crystal display unit 14, a self-luminous display such as an organic EL (Electroluminescence) display device or a plasma display device may be used. In the case of the self-luminous type, a backlight is not necessary, but in this case, the first polarizing plate 13 that is unnecessary in the self-luminous type is necessary.

  In the SW-LCD 12, a substrate 21, a transparent electrode film 26, an alignment film 24, a liquid crystal layer 23, an alignment film 25, a transparent electrode film 27, and a substrate 22 are formed in this order. The initial alignment direction of the liquid crystal molecules of the liquid crystal layer 23 is determined according to the alignment films 25 and 27, and the alignment direction can be changed by applying a voltage to the transparent electrodes 26 and 27 from a control unit (not shown). Only one of the alignment films 24 and 25 may be provided.

  The control unit changes the alignment direction of the liquid crystal molecules of the liquid crystal layer 23 to the alignment direction for the wide viewing angle mode or the narrow viewing angle mode according to the wide viewing angle mode or the narrow viewing angle mode set by the user. .

  The backlight 16 supplies light for display. The third polarizing plate 15 extracts linearly polarized light in a certain direction from the light of the backlight 16 before entering the main LCD 14. The first polarizing plate 13 extracts linearly polarized light in a certain direction from the light before passing through the main LCD 14 and entering the SW-LCD 12. The second polarizing plate 11 extracts linearly polarized light in a certain direction from the backlight light transmitted through the main LCD 14 and the SW-LCD 12.

  Here, the second polarizing plate 11 has a polarization region 51 for extracting linearly polarized light in a certain direction and a transmission region 52 for transmitting incident light as it is. As the shape of the region, the logo portion of “SHARP” as shown in FIG. 6 becomes the transmission region 52, and the other region becomes the polarization region 51. By doing so, the polarizing region 51 has the same characteristics as the configuration in which the liquid crystal layer 23 is sandwiched between two polarizing plates having the same polarization transmission axis, and the transmitting region 52 does not have such characteristics.

  As will be described in detail later, the SW-LCD 12 is controlled so that the liquid crystal molecules cause birefringence or not depending on the mode or the viewing direction. If the liquid crystal molecules are birefringent and light is sandwiched between two polarizing plates having the same polarization transmission axis, light will not be transmitted. On the other hand, when no polarizing plate is disposed on the light emission side, light is transmitted. Therefore, when the liquid crystal molecules are birefringent, light is not transmitted through the polarization region 51 but is transmitted through the transmission region 52. Therefore, the lower display image is displayed only in the transmission region 52, and light is not displayed in the polarization region 51 and black display is performed, and the display of “SHARP” as shown in FIG. 5 is displayed.

  The second polarizing plate 11 is, for example, pasted with a film-like polarizing plate (polarizing film) provided with an adhesive such as a single-sided acrylic adhesive (eg, Soken Chemical Co., Ltd., trade name: SK Dyne). Alternatively, if the second polarizing plate 11 is detachably attached by attaching the second polarizing plate to the slides arranged at both ends of the screen, the second polarizing plate 11 may have various formation regions where the polarization region 51 and the transmission region 52 are different. The two polarizing plates 11 can be replaced according to the user's preference and feeling without asking the trader. Therefore, it is possible to change the design that is visually recognized when viewed from an oblique direction in the multiple image display mode at low cost.

  In addition, when birefringence does not occur, light is transmitted even if sandwiched between two polarizing plates having the same polarization transmission axis (even in the polarization region 51). The image display on the main LCD 14 can be seen as it is.

  At this time, if there is a difference in transparency between the transmissive region 52 and the polarizing region 51, the brightness of the image that is visually recognized depends on whether it overlaps the transmissive region 52 or the polarizing region 51 in the image display of the main LCD 14. Changes, and a bright (or dark) image is formed only in the transmissive region 52, making it difficult to see. Therefore, the transmittance of the transmissive region 52 is preferably as close as possible to the transmittance of the polarizing region 51, and is 0.8 to 1.2 times, more preferably 0.9 times or more the transmittance of the polarizing region 51. It is preferable to adjust to 1.1 times or less. If the transmittance of the transmissive region 52 is lower than the above range, light transmission is less likely to occur in the portion that overlaps the transmissive region 52 of the main LCD 14 than in the portion that overlaps the polarization region 51, and the image looks darker, making it difficult to see the image. On the other hand, if the transmittance of the transmissive region 52 is larger than the above range, the portion of the image displayed on the main LCD 14 that overlaps the polarizing region 51 is less likely to transmit light than the portion that overlaps the transmissive region 52 and looks darker. Becomes difficult to see.

  In general, a polarizing plate has a lower transmittance than a material that simply transmits light for structural reasons. Therefore, a transmissive material such as an acrylic resin or PET is used as the material of the transmissive region 52, and a color filter pigment may be mixed with the transmissive material to adjust the transmittance.

  As the second polarizing plate 11, for example, a uniaxially stretched polyvinyl alcohol film adsorbed with iodine or a dichroic dye may be used as a polarizer. In this case, the polarizing plate that shows the function of the polarizing plate in a part of the region (polarizing region 51) and allows normal transmission in the other region (transmissive region 52) adjusts the adsorption position, stretching, etc. of iodine or dye. Or the like.

In FIG. 1, the second polarizing plate 11, the switch liquid crystal display unit 12, the first polarizing plate 13, and the main liquid crystal display unit 14 are
(A) Main liquid crystal display unit 14-first polarizing plate 13-switch liquid crystal display unit 12-second polarizing plate 11 → arranged in this order, but in addition to this, the following (B) to (F) Such a configuration is also possible.
(B) first polarizing plate 13-switch liquid crystal display unit 12-second polarizing plate 11-main liquid crystal display unit 14 → observer main liquid crystal display unit 14 is a liquid crystal display unit using a display polarizing plate (C) main Liquid crystal display unit 14-display polarizing plate-first polarizing plate 13-switch liquid crystal display unit 12-second polarizing plate 11 → observer
When the first polarizing plate 13 also serves as a display polarizing plate (a rotating means for rotating linearly polarized light may be necessary).
(D) Main liquid crystal display unit 14- (rotating unit) -first polarizing plate 13 (also serving as a polarizing plate for display)-(rotating unit) -switch liquid crystal display unit 12- (rotating unit) -second polarizing plate 11 → Observer
(E) first polarizing plate 13-switch liquid crystal display unit 12-second polarizing plate 11-display polarizing plate-main liquid crystal display unit 14-display polarizing plate → observer second polarizing plate 11 serves as a display polarizing plate. (In some cases, a rotating means for rotating linearly polarized light may be required.)
(F) First polarizing plate 13-Switch liquid crystal display unit 12-First polarizing plate 13 (also used as a display polarizing plate)-(Rotating means) -Main liquid crystal display unit 14- (Rotating means) -Display polarizing plate → Observer When adopting the configuration as described above, whether the first polarizing plate 13 or the second polarizing plate 11 can form a specific pattern by the transmission region depends on the above (A) to (F). Differently, the following patterns (1) to (4) are conceivable.
(1) Both the first polarizing plate 13 and the second polarizing plate 11 ... A, B, C, E
(2) Only the first polarizing plate 13: A to F
(3) Only the second polarizing plate 11: A to F
(4) When only the second polarizing plate 11 can be changed by the user, A to D,
Next, examples of alignment of liquid crystal molecules in four SW-LCDs will be described with reference to FIGS.

(SW-LCD liquid crystal molecular alignment example 1)
FIG. 6A shows the display surface of the display unit 4 of the mobile phone 1 so that the vertical direction of the image of the main-LCD 14 is the vertical direction of the paper. Hereinafter, the horizontal direction on the display screen is referred to as the x direction, the vertical direction is referred to as the y direction, and the thickness direction of the display unit 4 is referred to as the z direction. In FIGS. 5 to 10, the transparent electrode films 26 and 27 and the alignment films 24 and 25 are omitted.

  First, as shown in FIG. 6A, the polarization transmission axes of the second polarizing plate 11 and the first polarizing plate 13 are arranged in the y direction. In addition, the rubbing direction of the alignment films 24 and 25 is made parallel to the polarization transmission axes of the first and second polarizing plates 11 and 13 and opposite to each other by 180 degrees, so that the alignment direction has an anti-parallel structure. Then, a polyimide material of a horizontal alignment material is used as the alignment films 24 and 25, and liquid crystal molecules are aligned so as to be substantially parallel to the substrates 21 and 22. Thus, the liquid crystal molecules are uniaxially aligned so that the major axis direction of the liquid crystal molecules is substantially parallel to the polarization transmission axis.

  In this case, as shown in the AA ′ cross-sectional view of FIG. 6B, the liquid crystal molecules of the SW-LCD 12 are uniaxially aligned substantially parallel to the polarization transmission axis of the first polarizing plate 13 in the state of no voltage applied. Yes. Light incident on the SW-LCD 12 from the backlight 16 via the main LCD 14 is transmitted through the first polarizing plate 13, so that the polarization direction of the light incident on the SW-LCD 12 and the alignment direction “a” of the liquid crystal molecules are substantially the same. .

  FIG. 6C shows how the liquid crystal molecules are seen when the SW-LCD 12 in this state is viewed while being displaced in the x direction. According to the figure, the shape when the liquid crystal molecules are projected from the front direction (the shape of the liquid crystal molecules as viewed from the observer 31) is the liquid crystal molecules 35a, and the major axis direction and the polarization direction of the incident light substantially coincide. ing. When the angle formed by the major axis direction of the projection diagram of the liquid crystal molecules and the polarization direction of the incident light is 0 degree, the incident light is transmitted without being affected by birefringence. Regardless of the polarization region 51, the image of the main LCD 14 can be seen as it is in the entire region. Similarly, the shape of the liquid crystal molecules projected from the point deviated in the x direction from the front (the shape of the liquid crystal molecules as viewed from the observers 32 and 33) is also the liquid crystal molecules 35b and 35c, and is incident on the major axis direction. The polarization directions of the light are substantially the same. Therefore, the image of the main LCD 14 can be seen in the entire area when viewed from any direction. This state, that is, the state in which no voltage is applied, is set as the wide viewing angle mode.

  On the other hand, in the narrow viewing angle mode, the liquid crystal molecules are inclined 45 degrees with respect to the substrates 21 and 22 (upper end is on the viewer side) by rotation about the x direction from the state where no voltage is applied. An AC voltage (for example, a voltage of 100 Hz, 3 V) is applied to the electrode films 25 and 26. The state of the liquid crystal molecules at this time is shown in FIGS. FIG. 7A shows an A-A ′ cross section, and it is understood that the substrate is inclined at about 45 degrees with respect to the substrates 21 and 22. FIG. 7B shows a B-B ′ cross section, in which the liquid crystal molecules are inclined 45 degrees from the normal direction to the paper surface.

  In this case, as shown in FIG. 7B, the liquid crystal molecules viewed from the observer 31, that is, the projection view of the liquid crystal molecules from the front direction, is the liquid crystal molecules 36a. Since the orientation change of the liquid crystal molecules is caused by rotation about the x-axis direction, the polarization directions of the second polarizing plate 11 and the first polarizing plate 13 always coincide with the major axis direction of the liquid crystal molecules 36a. For this reason, when viewed from the front direction (when viewed by the observer 31 in FIG. 7), the image of the main LCD 14 can be seen as it is in the entire region without being affected by birefringence.

  On the other hand, the liquid crystal molecules viewed from the viewer 32 on the left side toward the display unit 4, that is, the projections of the liquid crystal molecules projected from the left side toward the substrates 21 and 22 are tilted to the right like the liquid crystal molecules 36b. Yes. In this case, since the polarization direction of the second polarizing plate 11 and the first polarizing plate 13 has an angle of 45 degrees with the major axis direction of the projection diagram, the major axis direction of the liquid crystal molecule projection diagram is the polarization direction of the incident light. It has a 45 degree crossing angle. Therefore, when viewed from the observer 32, light is not transmitted through the polarization region 51 of the SW-LCD 12 due to the influence of the birefringence of the liquid crystal, and the image of the main LCD 12 cannot be seen.

  Similarly, a liquid crystal molecule viewed from the observer 33 on the right side toward the display unit 4, that is, a projection diagram of the liquid crystal molecule from the right side toward the substrates 21 and 22 is a liquid crystal molecule 36c. Since the polarization direction of the second polarizing plate 11 and the first polarizing plate 13 has an angle with the major axis direction of the projection diagram, the major axis direction of the liquid crystal molecule projection diagram has an intersection angle with the polarization direction of the incident light, The polarization direction rotates. Therefore, when viewed from the observer 33, light is not transmitted through the polarization region 51 of the SW-LCD 14 due to the influence of the birefringence of the liquid crystal, and the image on the main LCD 12 cannot be seen.

  When a voltage is applied to the transparent electrode films 26 and 27 by the above-described mechanism, as shown in FIG. 4, when the display unit 4 is viewed from the front direction (when viewed by the observer 31), birefringence occurs. The image of the main LCD 14 can be seen as it is without being influenced by the light, but when viewed from the direction other than the front direction (when viewed by the viewers 32 and 33), the polarization region 51 of the SW-LCD is affected by the birefringence. Does not pass through and the image on the main LCD 14 becomes invisible.

  In addition, the orientation direction of the liquid crystal molecules in the narrow viewing angle mode is not limited to 45 degrees with respect to the substrates 21 and 22, and any angle can be used as long as it is inclined with respect to the substrates 21 and 22. But it doesn't matter. In other words, it may be larger than the inclination angle when substantially parallel to the substrates 21 and 22 and smaller than the inclination angle when substantially vertical (that is, if it is larger than 0 degree and smaller than 90 degrees). The inclination angle is preferably 10 degrees or more and 80 degrees or less, and more preferably 40 degrees or more and 50 degrees or less. This is because the birefringence increases as the inclination angle approaches 45 degrees, and the image can be favorably hidden. Further, when the tilt angle is small, the driving voltage is small, so that power consumption can be reduced.

  Note that when the observer is displaced in the y direction, the major axis direction of the projection diagram of the liquid crystal molecules does not change, so whether or not the main LCD 12 is visible depends only on the displacement of the viewpoint in the x direction. Therefore, the line of sight parallel to the yz plane (the plane drawn by the rotation of the liquid crystal molecules to change the alignment direction) is taken as the line of sight from the front direction.

(SW-LCD liquid crystal molecular alignment example 2)
A liquid crystal molecule alignment example 2 of the SW-LCD will be described with reference to FIG. Liquid crystal molecule alignment example 2 is realized by using SW-LCD 12 ′ using an alignment film using a polyimide material of a vertical alignment material instead of alignment films 24 and 25 in SW-LCD 12. As a result, as shown in FIG. 8A, the liquid crystal molecules are aligned so as to be substantially perpendicular to the substrates 21 and 22.

  In this case, the liquid crystal molecules of the SW-LCD 12 ′ are uniaxially aligned substantially perpendicular to the substrates 21 and 22 in the state where no voltage is applied. That is, when viewed from the front, the liquid crystal molecules 37a look like a perfect circle (when the projection is a perfect circle, all directions are considered to be major axis directions). And when it sees from directions other than the front, a major axis direction turns into x direction like a liquid crystal molecule 37b * 37c in a projection figure. Therefore, in the case of projecting from any direction including the front direction, the major axis direction b and the polarization direction of incident light are 90 degrees. If the angle between the major axis direction of the liquid crystal molecule projection by incident light and the polarization direction of the incident light is 90 degrees (right angle), the incident light is transmitted without being affected by birefringence, so any angle Even when viewed from above, the image of the main LCD 14 can be seen as it is in the entire region. This state, that is, the state in which no voltage is applied, is set as the wide viewing angle mode.

  On the other hand, in the narrow viewing angle mode, the AC voltage is applied to the transparent electrode films 26 and 27 so that the liquid crystal molecules are inclined 45 degrees with respect to the substrates 21 and 22 by the rotation about the x direction from the state of the wide viewing angle mode. multiply. The state of the liquid crystal molecules at this time is the same as in the case of the alignment example 1 of the SW-LCD shown in FIG.

  Therefore, when a voltage is applied to the transparent electrode films 26 and 27 by the same mechanism, as shown in FIG. 3, the display unit 4 is birefringent when viewed from the front (when viewed by the observer 31). The image of the main LCD 14 can be seen as it is without being influenced by the image, but when viewed from the direction other than the front direction (when viewed by the observers 32 and 33), the logo image is seen due to the effect of birefringence.

(SW-LCD liquid crystal molecular alignment example 3)
FIG. 9A shows the display unit 4 of the mobile phone 1 so that the vertical direction of the display screen is the vertical direction of the page.

  First, as shown in FIG. 9A, the polarization transmission axes of the first polarizing plate 13 and the second polarizing plate 11 are arranged in the x direction. Then, the rubbing direction of the alignment films 24 and 25 is perpendicular to the polarization transmission axes of the first polarizing plate 13 and the second polarizing plate 11 (y direction) and opposite to each other by 180 degrees, and the alignment direction is antiparallel. Make the structure. Then, a polyimide material of a horizontal alignment material is used as the alignment films 24 and 25, and liquid crystal molecules are aligned so as to be substantially parallel to the substrates 21 and 22. Accordingly, as shown in FIG. 9B, the liquid crystal molecules are uniaxially aligned so that the major axis direction of the liquid crystal molecules is substantially perpendicular to the polarization transmission axis of the polarizing plate.

  In this case, as shown in FIG. 9B, the liquid crystal molecules of the SW-LCD 12 are parallel to the substrates 21 and 22 and perpendicular to the polarization transmission axis of the first polarizing plate 13 in the state where no voltage is applied. Is uniaxially oriented. The light incident from the backlight 16 through the main LCD 14 is transmitted through the first polarizing plate 13, so that the polarization direction of the light incident on the SW-LCD 12 and the alignment direction of the liquid crystal molecules are substantially perpendicular.

  FIG. 9C shows how the liquid crystal molecules appear when the SW-LCD 12 in this state is viewed while being shifted in the x direction. According to the figure, the shape when projected from the front direction (the shape of the liquid crystal molecules as viewed from the observer 31) is the liquid crystal molecules 38a, and the major axis direction c of the projected liquid crystal molecules and the polarization direction of the incident light Becomes a right angle. When the angle between the major axis direction of the liquid crystal molecule projection and the polarization direction of the incident light is 90 degrees, the incident light is transmitted without being influenced by birefringence. Regardless of the transmission region 52 and the polarization region 51, the image of the main LCD 14 can be seen in the entire region. This state, that is, the state in which no voltage is applied, is set as the wide viewing angle mode.

  On the other hand, in the narrow viewing angle mode, an AC voltage is applied to the transparent electrode films 25 and 26 so that the liquid crystal molecules are inclined 45 degrees with respect to the substrates 21 and 22 by rotation about the x direction from the state where no voltage is applied. Call. The state of the liquid crystal molecules at this time is shown in FIG. FIG. 10A shows an A-A ′ cross section, and it can be seen that the substrate is inclined at 45 degrees with respect to the substrates 21 and 22. FIG. 10B shows a B-B ′ cross section, in which the liquid crystal molecules are inclined 45 degrees from the normal direction to the paper surface.

  In this case, as shown in FIG. 10B, a liquid crystal molecule viewed from the observer 31, that is, a projection view of the liquid crystal molecule from the front direction, is a liquid crystal molecule 39a. Since the change in the alignment direction of the liquid crystal molecules is due to rotation about the x direction, the polarization direction of the second polarizing plate 11 and the first polarizing plate 13 is perpendicular to the major axis direction of the liquid crystal molecules 39a. Therefore, the projection view of the liquid crystal molecules, the major axis direction, and the polarization direction of the incident light are substantially perpendicular. Therefore, when viewed from the front direction (when viewed by the observer 31), the image on the main LCD 14 can be seen as it is without being affected by birefringence.

  On the other hand, the liquid crystal molecules viewed from the viewer 32 on the left side toward the display unit 4, that is, the projections of the liquid crystal molecules from the left side toward the substrates 21 and 22 become liquid crystal molecules 39b. Since the polarization transmission axes of the second polarizing plate 11 and the first polarizing plate 13 have an angle with the major axis direction of the projection diagram, the major axis direction of the liquid crystal molecule projection diagram has a crossing angle with the polarization direction of incident light. Therefore, when viewed from the observer 32, light does not pass through the polarization region 51 of the SW-LCD 12 due to the influence of the birefringence of the liquid crystal, and the image of the main LCD 12 cannot be seen at this portion.

  Similarly, a liquid crystal molecule viewed from the observer 33 on the right side toward the display unit 4, that is, a projection diagram of the liquid crystal molecule from the right side toward the substrates 21 and 22 is a liquid crystal molecule 35c. Since the polarization transmission axes of the first polarizing plate 13 and the second polarizing plate 11 have an angle with the major axis direction of the projection diagram, the major axis direction of the liquid crystal molecule projection diagram has a crossing angle with the polarization direction of incident light. Therefore, when viewed from the observer 33, light does not pass through the polarization region 51 of the SW-LCD 12 due to the influence of the birefringence of the liquid crystal, and the image of the main LCD 12 cannot be seen at this portion.

  When a voltage is applied to the transparent electrode base films 26 and 27 by the above-described mechanism, as shown in FIG. 4, when the display unit 4 is viewed from the front direction (when viewed by the observer 31), a plurality of images are displayed. Although the image of the main LCD 14 can be seen as it is without being influenced by refraction, when viewed from other than the front direction (when viewed by the observers 32 and 33), the polarization region 51 of the SW-LCD 12 is affected by the influence of birefringence. The light is not transmitted, and the logo image overlaps the image on the main LCD 14.

(Liquid crystal molecular alignment example 4 of SW-LCD)
A liquid crystal molecule alignment example 4 of the SW-LCD will be described with reference to FIG. The alignment example 4 is realized by using the SW-LCD 12 ′ using an alignment film using a polyimide material of a vertical alignment material instead of the alignment films 24 and 25 in the alignment example 3 of the SW-LCD. Thereby, the liquid crystal molecules can be aligned so as to be substantially perpendicular to the substrates 21 and 22.

  In this case, the liquid crystal molecules of the SW-LCD 12 ′ are uniaxially aligned substantially perpendicular to the substrates 21 and 22 in the state where no voltage is applied. That is, as shown in FIG. 11B, when viewed from the front, it looks like a perfect circle of the liquid crystal molecules 40a. When viewed from a direction other than the front, the major axis direction appears to be the x direction as in the liquid crystal molecules 40b and 40c. Therefore, even when liquid crystal molecules are projected from any direction including the front direction, the major axis direction coincides with the polarization direction of incident light. When the angle between the major axis direction of the liquid crystal molecule projection and the polarization direction of the incident light is 0 degree (parallel), the incident light is transmitted without being affected by birefringence. However, the image of the main LCD 14 can be seen as it is in the entire area. This state, that is, the state in which no voltage is applied, is set as the wide viewing angle mode.

  On the other hand, in the narrow viewing angle mode, the AC voltage is applied to the transparent electrode films 26 and 27 so that the liquid crystal molecules are inclined 45 degrees with respect to the substrates 21 and 22 by the rotation about the x direction from the state of the wide viewing angle mode. multiply. The state of the liquid crystal molecules at this time is the same as that of SW-LCD alignment method 1 shown in FIG.

  Therefore, when a voltage is applied to the transparent electrode films 26 and 27 by the same mechanism, as shown in FIG. 4, when the display unit 4 is viewed from the front direction (when viewed by the observer 31), it is a transmission region. 52. Regardless of the polarization region 51, the image of the main LCD 14 can be seen as it is without being affected by birefringence in the entire region, but when viewed from other than the front direction (when viewed by the observers 32 and 33), birefringence is observed. As a result, the light is not transmitted through the polarization region 51 and a logo image can be seen.

  In the above description, the SW-LCD 12 is located on the front surface (display surface side) of the main LCD 14 as an example. However, like the display unit 44 in FIG. However, since the incidence of light on the main LCD 14 can be controlled, the viewing angle can be controlled. In the display unit 44, the polarizing plates 11 and 17 are disposed on both sides of the main LCD 14, and the alignment plate 13 is disposed on the outer surface of the SW-LCD 12.

  However, when the SW-LCD 12 is in front of the main LCD 14, the outline of the image superimposed by the SW-LCD 12 appears clearly. In the multi-image display mode, when the main LCD 14 performs transmissive liquid crystal display, the SW-LCD 12 may be on the front surface or the rear surface. However, when performing the reflective liquid crystal display, incident light is incident. Since it reflects without passing through the main LCD 14, the SW-LCD 12 must be disposed on the front surface of the main LCD 14.

  On the other hand, when the SW-LCD 12 is behind the main LCD 14, the light is not attenuated by the SW-LCD 12 when the main LCD 14 displays a reflective liquid crystal display. Therefore, when the transflective liquid crystal display device or the reflective liquid crystal display is performed in the single image display mode, the SW-LCD 12 is preferably disposed on the back surface of the main LCD 14.

  In the display device of the present invention, a single image display mode is set when no voltage is applied to the transparent electrode films 26 and 27, and a multiple image display mode is set by applying a predetermined voltage to the transparent electrode film. However, there may be a configuration in which the multiple image display mode is set in a state where no voltage is applied, and the single image display mode is set by applying a predetermined voltage to the transparent electrode film. This configuration is realized by pre-tilting the liquid crystal molecules, for example, at 45 degrees with respect to the substrate, and controlling the alignment so that the liquid crystal molecules are substantially perpendicular or substantially parallel to the substrate by applying a voltage. According to such a configuration, power consumption can be reduced when the narrow viewing angle is often set in the multiple image display mode.

  Furthermore, the display device of the present embodiment controls the viewing angle so that the image is not seen obliquely (from the left or right from the front) when facing the image on the main LCD 14, but the present invention is not limited to this. Alternatively, the viewing angle may be controlled so that the image cannot be seen obliquely from above or obliquely below.

  In order to realize this configuration, in the multiple image display mode, the liquid crystal molecules may be tilted in the left-right direction of the image displayed on the video display means. In other words, the video display means and the display switching means can be bonded so that the plane drawn by the dots on the liquid crystal molecules when the orientation changes is substantially parallel to the horizontal direction of the image displayed on the video display means. That's fine.

  In this embodiment, the case where the present invention is applied to a liquid crystal display unit of a mobile phone is described. However, the present invention is not limited to this, and a display device such as a mobile personal computer, an AV device, or a DVD player is used. Applicable to portable electronic devices. Alternatively, it may be applied to a non-portable display device and used as a display that can display differently depending on the viewing direction.

  Since the display device of the present invention can be set to a mode in which different images are visually recognized depending on the direction of the line of sight, the display of a portable electronic device such as a mobile communication terminal, a mobile personal computer, an AV device, a DVD player, or the line of sight It can be applied to a display or the like that can present a plurality of information depending on the direction.

It is a figure which shows sectional drawing of the display part of the mobile telephone which concerns on embodiment of this invention. It is a figure which shows the mobile telephone which concerns on embodiment of this invention. 6 is a diagram showing a display unit viewed from the front or oblique direction when the mobile phone according to the embodiment of the present invention is set to the single image display mode. 6 is a diagram illustrating a display unit that is viewed from the front or oblique direction when the mobile phone according to the embodiment of the present invention is set to the multiple image display mode. It is drawing which shows the 2nd polarizing plate concerning embodiment of this invention. The display part when the mobile telephone which concerns on embodiment of this invention is set to single image display mode is shown, (a) is drawing which looked at the display surface of the display part, (b) is A-. A sectional view showing an A 'section, and (c) is a sectional view showing a BB' section. The display part when the mobile telephone which concerns on embodiment of this invention is set to the multiple image display mode is shown, (a) is sectional drawing which shows an AA 'cross section, (b) is a BB' cross section. FIG. The display part when the mobile telephone which concerns on other embodiment of this invention is set to single image display mode is shown, (a) is sectional drawing which shows an AA 'cross section, (b) is B- It is sectional drawing which shows a B 'cross section. The display part when the mobile telephone which concerns on other embodiment of this invention is set to the single image display mode is shown, (a) is drawing which looked toward the display surface of the display part, (b) A sectional view showing an AA 'section, and (c) is a sectional view showing a BB' section. The display part when the mobile telephone which concerns on other embodiment of this invention is set to the multiple image display mode is shown, (a) is sectional drawing which shows an AA 'cross section, (b) is BB. It is a sectional view showing a section. The display part when the mobile telephone which concerns on other embodiment of this invention is set to single image display mode is shown, (a) is sectional drawing which shows an AA 'cross section, (b) is B- It is sectional drawing which shows a B 'cross section. It is a figure which shows sectional drawing of the display part of the mobile telephone which concerns on other embodiment of this invention.

Explanation of symbols

1 Mobile phone 4 Display unit (display device)
11 Second polarizing plate (second polarizing means)
12 switch liquid crystal display (display switching means)
13 First polarizing plate (first polarizing means)
14 Main liquid crystal display (image display means)
21 Substrate 22 Substrate 23 Liquid crystal layer 44 Display unit (display device)
51 Polarization region 52 Transmission region

Claims (10)

Video display means for displaying an image;
In order to electrically switch a visually recognized image between the single image display mode and the multiple image display mode, which is arranged in the optical path of light incident on the video display means or the optical path of light emitted from the video display means Display switching means,
A first polarization unit disposed in a path of light incident on the display switching unit, and a second polarization unit disposed in a path of light emitted from the display switching unit,
The display switching means includes a pair of substrates and a liquid crystal layer disposed between the substrates, the major axis direction when the liquid crystal molecules of the liquid crystal layer are projected from a direction orthogonal to the substrate, and The linear polarization direction of light incident on the liquid crystal molecules is always substantially parallel or substantially perpendicular,
In the single image display mode, the liquid crystal molecules are aligned such that the major axis direction of the liquid crystal molecules is substantially parallel or substantially perpendicular to the substrate. In the multiple image display mode, the major axis direction of the liquid crystal molecules is the substrate. Oriented to be inclined with respect to
At least one of the first polarizing means and the second polarizing means is provided with a transmission region having a polarization degree different from that of the polarization region.   The display device according to claim 1, wherein the transmittance of the transmissive region is not less than 0.8 times and not more than 1.2 times the transmittance of the polarizing region.   The display device according to claim 1, wherein at least one of the first polarizing unit and the second polarizing unit includes a dye.   The display device according to claim 1, wherein the transmissive region is provided only in the second polarizing means that is detachably attached. Single image display mode when no voltage is applied to the liquid crystal molecules,
The display device according to claim 1, wherein a plurality of image display modes are set by applying a predetermined voltage to the liquid crystal molecules. In the single image display mode, the image displayed by the video display means can be viewed from any direction,
6. The multi-image display mode according to claim 1, wherein, from a specific direction, the polarization region is visually recognized by overlapping with an image of the video display unit due to birefringence of the display switching unit. Display device.   The display device according to claim 1, wherein in the multiple image display mode, the liquid crystal molecules are inclined in the vertical direction in an image displayed on the video display means.   8. The display device according to claim 1, wherein an angle formed between a major axis direction of liquid crystal molecules and the substrate is 40 degrees or more and 50 degrees or less in the multi-image display mode.   A polarizer that functions as the second polarizing means of the display device according to claim 1 and is detachably attached to the display switching means. A viewing angle control device that controls and outputs the viewing angle of incident light,
A liquid crystal element;
A polarizing region that is provided on the liquid crystal element and that extracts linearly polarized light, and a transmissive region that transmits light as it is, and includes linearly polarizing means arranged to form a specific pattern;
The major axis direction of the liquid crystal molecules of the liquid crystal element is included in the plane formed by the direction of the transmission axis or absorption axis of the linearly polarizing means and the traveling direction of light,
The viewing angle control device according to claim 1, wherein the liquid crystal molecules can take a state of being substantially perpendicular or substantially parallel to a light traveling direction and a state of being inclined with respect to the light traveling direction.

Images