JP6068052B2 - Liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal display element.

  A liquid crystal display element is configured by sandwiching a liquid crystal layer between a pair of substrates. When the liquid crystal display element is used as a transmission type, a light-transmitting substrate such as a glass substrate is used. The liquid crystal layer can be formed from, for example, a nematic phase liquid crystal (hereinafter also referred to as a nematic liquid crystal). A patterned electrode made of a transparent conductive material such as ITO (Indium Tin Oxide) can be provided on the surface of each substrate on the liquid crystal layer side. The shape of the electrode corresponds to the display pattern in the liquid crystal display element. A liquid crystal alignment film that realizes uniform initial alignment of the liquid crystal layer is preferably provided between the electrode on each substrate and the liquid crystal layer.

  Further, in the liquid crystal display element, it is preferable that a pair of polarizing plates is provided on each substrate sandwiching the liquid crystal layer. In the liquid crystal display element, the orientation of the liquid crystal layer changes from the initial state in accordance with the electric field applied between the electrodes on each substrate. The liquid crystal display element can display an image by using the change in orientation of the liquid crystal layer and controlling light transmitted between the liquid crystal layer and the polarizing plate.

  Such a liquid crystal display element has features such as thinness, high resolution, and low driving voltage. Liquid crystal display elements are used as display elements for various devices such as clocks, calculators, home appliances, televisions, slot machines and other gaming machines, automobile instrument panels, and personal computer display elements. Yes.

  In the liquid crystal display element, as one of the techniques corresponding to such expansion of applications, there is a technique for making the function as a mirror (mirror) compatible in addition to the function as a conventional display element. The technology includes, for example, a reflective polarizing plate having a reflection axis (polarization axis during reflection) and a transmission axis (polarization axis during transmission) orthogonal to each other on the front surface of a liquid crystal display element. In addition to the functions described above, it can be used as a mirror (see, for example, Patent Document 1 and Patent Document 2).

JP 2004-246004 A JP 2010-79087 A

  In such a liquid crystal display element that also functions as a mirror, there has been a demand for a function of suppressing glare and glare that a viewer feels when strong light is incident from the outside. That is, a liquid crystal display element that functions as a mirror is required to have an antiglare function and improve visibility.

  In addition, in the liquid crystal display element that functions as a display element or a mirror using the reflective polarizing plate having the above-described characteristics, the visibility is improved particularly for a viewer wearing polarized glasses such as sunglasses. There was a demand.

  Polarized glasses such as sunglasses are worn and used by viewers so as to suppress glare and glare felt by the influence of outside light and the like.

  In that case, if the viewer wears polarized glasses and observes the liquid crystal display element using the above-described reflective polarizing plate, the display on the liquid crystal display element may not be visible, and conversely, the function as a mirror may be achieved. It sometimes disappeared.

  These problems stem from the structure of polarized glasses. In other words, polarized glasses such as sunglasses can transmit only linearly polarized light in the vertical direction (the direction perpendicular to the horizontal direction) when worn so as to suppress glare, glare, blurring, etc. felt by the viewer. It is configured. That is, polarized glasses such as sunglasses are set such that the transmission axis of polarized light is in the vertical direction perpendicular to the horizontal direction.

  In that case, if the reflection axis of the reflection type polarizing plate disposed on the front surface of the liquid crystal display element is set in the vertical direction (vertical direction), the transmission axis of the reflection type polarizing plate is in the horizontal direction. The transmission axis of the polarizing glasses is parallel to the reflection axis of the reflective polarizing plate and is orthogonal to the transmission axis of the reflective polarizing plate. Therefore, the image light emitted from the liquid crystal display element as light polarized in a direction parallel to the transmission axis of the reflective polarizing plate cannot be transmitted through the polarizing glasses and is absorbed. As a result, the liquid crystal display element can function as a mirror, but the function as a display element is lost.

  In addition, when the reflection axis of the reflective polarizing plate disposed in front of the liquid crystal display element is set in a horizontal direction (a direction perpendicular to the vertical direction described above), the transmission axis of the reflective polarizing plate is the vertical direction. As a result, the transmission axis of the polarizing glasses is set in a direction perpendicular to the reflection axis of the reflective polarizing plate and parallel to the transmission axis of the reflective polarizing plate. Therefore, in the liquid crystal display element, the reflected light from the reflective polarizing plate cannot be transmitted through the polarizing glasses and is absorbed. As a result, the function as a display element can be exhibited, but the function as a mirror is lost.

  Therefore, in the liquid crystal display element, a reflective polarizing plate is used, and an anti-glare function is provided, and the function as a mirror and the function as a display element are both achieved for a viewer wearing polarized glasses, There is a need for a technique that can improve visibility.

  The present invention has been made in view of the above points. That is, an object of the present invention is to provide a liquid crystal display element having both a mirror function and a display element function and improved visibility.

  Other objects and advantages of the present invention will become apparent from the following description.

According to a first aspect of the present invention, a first substrate having a first electrode and a second electrode on a second surface on the back side opposite to the first surface on the front side,
A first electrode disposed opposite to the first substrate and facing the second surface of the first substrate, a third electrode facing the first electrode, and a fourth electrode facing the second electrode A second substrate having electrodes;
A liquid crystal layer sandwiched between the second surface side of the first substrate and the first surface side of the second substrate;
A polarizing plate disposed on the first surface side of the first substrate;
A reflective polarizing plate that is disposed on the second surface side which is the back side of the second substrate and reflects light polarized in a direction perpendicular to the transmission axis;
A backlight disposed on the back side of the reflective polarizing plate,
A liquid crystal display element in which a facing region between the first electrode and the third electrode forms a first region, and a facing region between the second electrode and the fourth electrode forms a second region,
The liquid crystal in the liquid crystal layer has negative dielectric anisotropy,
Each of the second surface of the first substrate and the first surface of the second substrate is provided with a vertical alignment liquid crystal alignment film in contact with the liquid crystal layer, and the liquid crystal alignment film has a pretilt angle of the liquid crystal of the liquid crystal layer. So that the film is vertically aligned with respect to the horizontal direction in a direction of 35 ° to 55 °.
The polarizing plate is disposed so that its transmission axis is in the direction of 35 ° to 55 ° with the direction of the alignment treatment of the liquid crystal alignment film,
The reflective polarizing plate is arranged so that its transmission axis is orthogonal to the transmission axis of the polarizing plate,
By applying a voltage between the first electrode and the third electrode and between the second electrode and the fourth electrode, the orientation of the liquid crystal is changed independently of each other in the first region and the second region. The present invention relates to a liquid crystal display element configured to control reflection of light from a reflective polarizing plate and transmission of light from a backlight.

According to a second aspect of the present invention, a first substrate having a first electrode and a second electrode on a second surface on the back side opposite to the first surface on the front side;
A first electrode disposed opposite to the first substrate and facing the second surface of the first substrate, a third electrode facing the first electrode, and a fourth electrode facing the second electrode A second substrate having electrodes;
A liquid crystal layer sandwiched between the second surface side of the first substrate and the first surface side of the second substrate;
A polarizing plate disposed on the first surface side of the first substrate;
A reflective polarizing plate that is disposed on the second surface side which is the back side of the second substrate and reflects light polarized in a direction perpendicular to the transmission axis;
A backlight disposed on the back side of the reflective polarizing plate,
A liquid crystal display element in which a facing region between the first electrode and the third electrode forms a first region, and a facing region between the second electrode and the fourth electrode forms a second region,
The liquid crystal in the liquid crystal layer has positive dielectric anisotropy,
A horizontal alignment liquid crystal alignment film in contact with the liquid crystal layer is provided on each of the second surface side of the first substrate and the first surface side of the second substrate, and the liquid crystal alignment film on the first substrate is: An alignment process in the direction of 85 ° to 95 ° with respect to the horizontal direction or −5 ° to 5 ° in the clockwise direction with respect to the horizontal direction is performed, and the liquid crystal alignment film on the second substrate is aligned with the first substrate. Depending on the direction of the liquid crystal, the alignment treatment is performed in the direction of -5 ° to 5 ° clockwise with respect to the horizontal direction or 85 ° to 95 ° with respect to the horizontal direction, and the liquid crystal of the liquid crystal layer is twisted to 80 ° to 100 °. Configured to be oriented,
The polarizing plate is arranged so that its transmission axis is parallel to the direction of the alignment treatment of the liquid crystal alignment film on the first substrate,
The reflective polarizing plate is arranged so that its transmission axis is orthogonal to the transmission axis of the polarizing plate,
By applying a voltage between the first electrode and the third electrode and between the second electrode and the fourth electrode, the orientation of the liquid crystal is changed independently of each other in the first region and the second region. The present invention relates to a liquid crystal display element configured to control reflection of light from a reflective polarizing plate and transmission of light from a backlight.

  In the first aspect of the present invention, it is preferable that a liquid crystal display element with a backlight or a light emitting display element is disposed instead of the backlight. In the second aspect of the present invention, it is preferable that a liquid crystal display element with a backlight or a light emitting display element is disposed instead of the backlight.

  In the first aspect of the present invention, a first optical sensor that senses light incident from a first direction facing the first surface of the first substrate, and light incident from the surroundings other than the first direction. A second photosensor for sensing, and comparing the intensity of light sensed by the first photosensor with the intensity of light sensed by the second photosensor, It is preferable to control the reflection of light from the reflective polarizing plate in at least one of the two regions.

  In the second aspect of the present invention, the first optical sensor that senses light incident from a first direction facing the first surface of the first substrate, and the light is incident from the surroundings other than the first direction. A second light sensor for sensing light, comparing the intensity of light sensed by the first light sensor with the intensity of light sensed by the second light sensor, and comparing the first region and It is preferable to control the reflection of light from the reflective polarizing plate in at least one of the second regions.

  In the first aspect of the present invention, the first region becomes a mirror region using reflection of light from the reflective polarizing plate, and the liquid crystal is applied by applying a voltage between the first electrode and the third electrode. It is preferable to be configured to control the reflection of light from the reflective polarizing plate.

  In the second aspect of the present invention, the first region becomes a mirror region using reflection of light from the reflective polarizing plate, and the liquid crystal is applied by applying a voltage between the first electrode and the third electrode. It is preferable to be configured to control the reflection of light from the reflective polarizing plate.

  According to the first aspect of the present invention, there is provided a liquid crystal display element having both a function as a mirror and a function as a display element and improved visibility.

  According to the 2nd aspect of this invention, the function as a mirror and the function as a display element are made compatible, and the liquid crystal display element with which visibility was improved is provided.

It is a figure which shows an example of the liquid crystal display element of this invention, (a) is a front view of an example of the liquid crystal display element of this invention, (b) is a character using an example of the liquid crystal display element of this invention. It is a figure which shows the state which performed the display. It is a figure which shows another example of the liquid crystal display element of this invention. It is a figure explaining the fall of the visibility in the liquid crystal display element of this invention, (a) is a figure which shows the setting of the reflective axis and transmission axis of the reflective polarizing plate of a liquid crystal display element, (b) It is a figure explaining the polarizing glasses used and the fall of visibility by it. It is a figure explaining another example of the visibility fall concerned with the liquid crystal display element of this invention, (a) is a figure which shows the setting of the reflective axis of the reflective polarizing plate of a liquid crystal display element, and a transmission axis. (B) is a figure explaining the polarizing glasses used and the fall of visibility by it. It is typical sectional drawing which shows the structure of the liquid crystal display element of embodiment of this invention. It is typical sectional drawing which shows the structure of the liquid crystal display element which is another example of embodiment of this invention. It is a figure which shows the arrangement | positioning relationship of the optical axis of each component in the liquid crystal display element of 1st Example of this invention. It is a figure which shows the arrangement | positioning relationship of the optical axis of each component in the liquid crystal display element of 2nd Example of this invention. It is a figure which shows the arrangement | positioning relationship of the optical axis of each component in the liquid crystal display element of 3rd Example of this invention.

  The inventor uses a reflective polarizing plate that reflects light polarized in a direction orthogonal to the transmission axis, and combines it with a liquid crystal panel that is sandwiched between a liquid crystal layer and a pair of translucent substrates. In the display area, the first area has a mirror area having a mirror function, and the second area has a display area having an information display function so that both the mirror function and the display function can be achieved. Display element technology was developed.

  As described above, the reflective polarizing plate has a transmission axis that transmits only light polarized in a specific direction, and reflects light polarized in a direction orthogonal to the transmission axis. Conventional polarizing plates absorb light polarized in a direction perpendicular to the transmission axis, and the light utilization efficiency is 50% or less. On the other hand, the reflective polarizing plate used here does not absorb light and can reflect light polarized in a direction orthogonal to the transmission axis. The present inventors use the light reflection function of the reflective polarizing plate as a mirror, and use the light transmission function that transmits polarized light in a predetermined direction for image display.

  The inventor then applies the developed technology to a rearview mirror (sometimes referred to as a rearview mirror or the like) disposed near the upper portion of the windshield in front of the driver's seat of a vehicle such as an automobile. We have developed a liquid crystal display device that has both a mirror function and an information display function.

  FIG. 1 is a diagram showing an example of the liquid crystal display element of the present invention, FIG. 1 (a) is a front view of an example of the liquid crystal display element of the present invention, and FIG. 1 (b) is a liquid crystal of the present invention. It is a figure which shows the state which performed the character display using an example of a display element.

  A liquid crystal display element 100 which is an example of the present invention has an appearance as a rearview mirror, has a mirror region 101 indicating a mirror state, and displays character information and the like in a display region 102 provided in a part of the mirror region 101. It is configured to display. Note that the display region 102 of the liquid crystal display element 100 is schematically shown as a region surrounded by a dotted line in FIG.

  FIG. 2 is a diagram showing another example of the liquid crystal display element of the present invention.

  A liquid crystal display element 200 which is another example of the present invention shown in FIG. 2 includes a mirror region 201 having a mirror function and a rectangular display region 202 provided in a part of the mirror region 201. The liquid crystal display element 200 is configured to display a desired image in the display area 202.

  However, it has also been clarified that the liquid crystal display element of the present invention has a problem in visibility. That is, as described above, when a viewer of a liquid crystal display element wears polarized glasses such as sunglasses and tries to visually recognize it, there is a concern that the visibility is lowered.

  FIG. 3 is a diagram for explaining a decrease in visibility in the liquid crystal display element of the present invention, and FIG. 3A is a diagram showing the setting of the reflection axis and transmission axis of the reflective polarizing plate of the liquid crystal display element. FIG. 3B is a diagram for explaining the polarized glasses used and the decrease in visibility due to the polarized glasses. At this time, the reflective polarizing plate is disposed on the front side of the liquid crystal display element.

  As shown in FIG. 3A, the liquid crystal display element 200 which is another example of the present invention can set the reflection axis 203 of the reflective polarizing plate (not shown) to be used in the horizontal direction. In that case, in the display area 202 provided together with the mirror area 201, light polarized in a direction parallel to the transmission axis 204 of the reflective polarizing plate is emitted as image light.

  Here, as described above, the polarized glasses 210 such as sunglasses can only be linearly polarized in the vertical direction (perpendicular to the horizontal plane) when worn so as to suppress glare, glare, blurring, etc. felt by the viewer. Is configured to be transmitted. That is, as shown in FIG. 3B, the polarizing glasses 210 such as sunglasses are set so that the transmission axis 211 is in the vertical direction as schematically indicated by the arrows.

  Therefore, the transmission axis 211 of the polarizing glasses 210 is set in a direction perpendicular to the reflection axis 203 of the reflective polarizing plate and parallel to the transmission axis 204 of the reflective polarizing plate. Therefore, image light emitted from the display region 202 as light polarized in a direction parallel to the transmission axis 204 of the reflective polarizing plate is transmitted through the polarizing glasses 210. On the other hand, the reflected light from the reflective polarizing plate in the mirror region 201 cannot be transmitted through the polarizing glasses 210 and is absorbed. As a result, as shown in FIG. 3B, the liquid crystal display element 200 uses the display area 202 and can function as a display element, but the function of the mirror area 201 as a mirror is lost.

  FIG. 4 is a diagram for explaining another example of a decrease in visibility which is a concern with the liquid crystal display element of the present invention. FIG. 4A shows the reflection axis and the transmission axis of the reflective polarizing plate of the liquid crystal display element. FIG. 4B is a diagram for explaining the setting, and FIG. 4B is a diagram for explaining the polarized glasses used and the decrease in the visibility due thereto. At this time, the reflective polarizing plate is disposed on the front side of the liquid crystal display element.

  As shown in FIG. 4A, a liquid crystal display element 200 ′, which is another example of the present invention, has a reflection axis 203 ′ of a reflection type polarizing plate (not shown) used in a vertical direction (perpendicular to the horizontal direction described above). In any direction). In that case, in the display region 202 ′ provided together with the mirror region 201 ′, light polarized in a direction parallel to the transmission axis 204 ′ of the reflective polarizing plate is emitted as image light.

  When the polarizing glasses 210 described above are worn, the transmission axis 211 of the polarizing glasses 210 is parallel to the reflection axis 203 ′ of the reflective polarizing plate and is orthogonal to the transmission axis 204 ′ of the reflective polarizing plate. . Therefore, image light emitted from the display region 202 ′ as light polarized in a direction parallel to the transmission axis 204 ′ of the reflective polarizing plate cannot be transmitted through the polarizing glasses 210 and is absorbed. On the other hand, the reflected light from the reflective polarizing plate in the mirror region 201 ′ can pass through the polarizing glasses 210. As a result, as shown in FIG. 4B, the liquid crystal display element 200 'can function as a mirror of the mirror region 201'. However, as schematically shown by a dotted line in FIG. 4B, the display area 202 'appears to disappear, and the function as a display element using the display area 202' is lost.

  In many cases, a driver of a vehicle such as an automated person wears sunglasses when driving to improve the driving environment and reduce fatigue. Therefore, the loss of the function of the liquid crystal display element used as a rearview mirror as described above becomes a problem. In particular, the loss of the mirror function may hinder driving and become a serious problem.

  Moreover, the liquid crystal display element of the present invention is suitable for use as a vehicle rearview mirror as described above. In such use, strong light may be irradiated from the outside by a headlight or the like of the following vehicle. When such strong external light is incident, the liquid crystal display element of the present invention reflects like a normal mirror, and may cause glare and glare to the driver as a viewer. For this reason, there has been a demand for a function of suppressing glare and glare that a viewer feels against strong light from the outside. That is, the liquid crystal display element of the present invention may be required to have an antiglare function and improve visibility.

  Therefore, the present inventor has conducted further studies and has developed a liquid crystal display element having a novel configuration in which the above-described problems are improved. It has both a mirror function and a display element function, and further has anti-glare performance and can improve visibility. Hereinafter, embodiments of the liquid crystal display element of the present invention will be described in more detail with reference to the drawings.

  FIG. 5 is a schematic cross-sectional view showing the structure of the liquid crystal display element of the embodiment of the present invention.

  A liquid crystal display element 1 according to an embodiment of the present invention shown in FIG. 5 has a mirror-like appearance (not shown) having a mirror-like appearance having the same rearview mirror-like appearance as the liquid crystal display element 100 illustrated in FIG. And a display area (not shown) for displaying character information and images.

  As shown in FIG. 5, the liquid crystal display element 1 of this embodiment is configured by laminating a backlight 2, a reflective polarizing plate 3, a liquid crystal panel 4, and an F polarizing plate 5 in this order. That is, in the liquid crystal display element 1, the liquid crystal panel 4 is sandwiched between the F polarizing plate 5 disposed on the front side which is a viewer (not shown) and the reflective polarizing plate 3 disposed on the back side. The On the back side of the liquid crystal panel 4, the backlight 2 is disposed on the back side of the reflective polarizing plate 3.

  The liquid crystal panel 4 is a transmissive liquid crystal panel. The liquid crystal panel 4 is made of a light transmissive material such as glass or resin, and includes a pair of substrates (not shown) including a first substrate disposed on the front side and a second substrate disposed on the back side. Is configured to sandwich a liquid crystal layer (not shown). In the liquid crystal panel 4, for example, a liquid crystal layer is sealed between the first substrate and the second substrate by a sealing material (not shown) provided at the peripheral portion.

  The 1st board | substrate of the liquid crystal panel 4 has a 1st electrode and a 2nd electrode in the 2nd surface used as the back side opposite to the 1st surface used as the front side (viewer side). The second substrate disposed opposite to the first substrate with the liquid crystal layer interposed therebetween has a third electrode facing the first electrode on the first surface facing the second surface of the first substrate, And a fourth electrode opposed to the second electrode. The liquid crystal layer includes a first surface of the first substrate on which the first electrode and the second electrode are disposed, and a first substrate on which the third electrode and the fourth electrode are disposed on the second substrate. It is sandwiched and arranged between the surface side.

  The first electrode and the second electrode on the first substrate, and the third electrode and the fourth electrode on the second substrate are each made of, for example, ITO (Indium Tin Oxide) or the like. A transparent electrode made of a transparent conductive material is preferable. Each electrode on the substrate is subjected to necessary patterning and formed into a desired shape. The shapes of the first electrode and the third electrode, and the second electrode and the fourth electrode of the liquid crystal panel 4 correspond to the shape of the mirror region and the display pattern in the display region in the liquid crystal display element 1. Can be formed. Further, the first electrode and the second electrode on the first substrate are segment electrodes, the third electrode and the fourth electrode on the second substrate are common electrodes, or the first electrode on the first substrate. The second electrode and the second electrode may be common electrodes, and the third and fourth electrodes on the second substrate may be segment electrodes.

  That is, in the liquid crystal display element 1 of the present embodiment, the facing region between the first electrode and the third electrode of the liquid crystal panel 4 forms a mirror region as the first region, and the second electrode and the fourth electrode A display region can be formed as a region opposite to the electrode as the second region. The liquid crystal display element 1 of the present embodiment is a control device that can be driven to change the orientation of the liquid crystal in the liquid crystal layer independently between the first region and the second region of the liquid crystal panel 4 ( (Not shown). Then, as described above, the liquid crystal display element 1 can be selectively used for the mirror function and the display function so that one of the first region and the second region is a mirror region and the other is a display region. Is possible.

  In the liquid crystal panel 4, the second surface on which the first electrode and the second electrode of the first substrate are formed, and the first surface on which the third electrode and the fourth electrode of the second substrate are formed. Each surface is preferably provided with a liquid crystal alignment film (not shown) that is in contact with the liquid crystal layer and realizes a uniform initial alignment of the liquid crystal layer. As the liquid crystal alignment film, a vertical alignment liquid crystal alignment film is preferably used.

  The liquid crystal layer of the liquid crystal panel 4 of the present embodiment is formed using, for example, nematic liquid crystal and has negative dielectric anisotropy.

  The liquid crystal layer of the liquid crystal panel 4 exhibits an initial alignment state in which the liquid crystal is vertically aligned between the first substrate and the second substrate. That is, the liquid crystal panel 4 is preferably a vertical alignment type liquid crystal panel 4. The vertical alignment type liquid crystal panel 4 can provide a liquid crystal display element having a wide viewing angle with an F polarizing plate 5 and a reflective polarizing plate 3 described later, and has a wide viewing angle suitable for viewing from the driver's seat. It is suitable for the configuration of a rearview mirror and a display element. Further, the vertical alignment type liquid crystal panel 4 uses a C plate or a biaxial film that is used as an optical compensation film for a VA (Vertical Alignment) mode liquid crystal display element. Since the dependency can be reduced, the viewing angle range that functions as a mirror can be further widened.

  The liquid crystal panel 4 may be a liquid crystal panel in a TN (Twisted Nematic) mode or an IPS (In-Plane Switching) mode, as will be described later.

  In the liquid crystal panel 4 of the present embodiment, the liquid crystal (not shown) has a predetermined pretilt angle with respect to each substrate in the initial alignment state of the liquid crystal layer to which no voltage is applied. It can be oriented to be vertically oriented.

  The pretilt angle of the liquid crystal in the liquid crystal layer in the initial alignment state is preferably 85.0 ° to 89.8 °. This is because when the angle is less than 85.0 °, it is impossible to form a sufficiently dark state in an initial alignment state where no voltage is applied. Further, when the angle is larger than 89.8 °, particularly when the vertical alignment is 90 °, it becomes difficult to control the direction in which the liquid crystal is tilted when a voltage is applied, resulting in alignment disorder and domains, resulting in liquid crystal display. This is because the performance of the element 1 as a mirror or a display element is deteriorated.

  Such an initial alignment state of the liquid crystal of the liquid crystal layer can be realized by subjecting a completely vertical alignment liquid crystal alignment film to an alignment treatment such as a rubbing treatment. The liquid crystal is inclined in the rubbing direction (also simply referred to as a rubbing direction) to have a pretilt angle. The direction in which the liquid crystal tilts is the direction in which the liquid crystal having negative dielectric anisotropy tilts when a voltage is applied between the substrates that sandwich the liquid crystal layer using the electrodes.

  In the liquid crystal display element 1 of the present embodiment described above, the direction in which the vertically aligned liquid crystal layer of the liquid crystal panel 4 is tilted by voltage application is defined by the direction of alignment processing such as rubbing processing of the liquid crystal alignment film. However, in the embodiment of the present invention, the direction in which the liquid crystal layer is tilted is realized not only by the alignment process but also by another method, for example, by setting the electrode structure to a desired one with a slit structure or the like. It is also possible to do.

  In the liquid crystal display element 1 of the present embodiment, as will be described later, the optical axis of each component is set so as to correspond to the transmission axis in the vertical direction of the polarizing glasses worn by the viewer. Therefore, the liquid crystal panel 4 is configured so that the liquid crystal tilts in a tilt direction that is in the direction of 35 ° to 55 ° with respect to the horizontal direction, and more preferably in a tilt direction that is in the direction of 45 °, by applying the voltage between the substrates. It is configured.

  An F polarizing plate 5 is disposed as a polarizing plate on the front side of the liquid crystal panel 4 and on the first surface side of the first substrate. The reflective polarizing plate 3 is disposed on the back surface side of the liquid crystal panel 4 and on the second surface side which is the back surface side of the second substrate. Therefore, a pair of polarizing plates, that is, the F polarizing plate 5 and the reflective polarizing plate 3 are arranged on both upper and lower sides of the liquid crystal layer of the liquid crystal panel 4.

  The F-polarizing plate 5 on the front side which is the viewer side of the liquid crystal panel 4 has a transmission axis of a direction in which the liquid crystal layer is inclined by application of a voltage and a direction of 35 ° to 55 °, preferably 45 °. Arranged in the direction. More specifically, the transmission axis of the F-polarizing plate 5 is arranged in the direction of 35 ° to 55 °, preferably in the direction of 45 ° with respect to the alignment treatment direction of the liquid crystal alignment film described above.

  At this time, in the liquid crystal display element 1 of the present embodiment, the transmission axis of the front F-polarizing plate 5 which is the viewer side is set in a direction parallel to the transmission axis of polarized glasses such as sunglasses worn by the viewer. It is preferable. In the polarizing glasses, the transmission axis is normally set in the vertical direction (the direction perpendicular to the horizontal direction). Therefore, the transmission axis of the F-polarizing plate 5 is similarly set to be in the vertical direction. Is preferred.

  A reflective polarizing plate 3 is disposed on the back side of the liquid crystal panel 4. As described above, the reflective polarizing plate 3 is a polarizing plate that has a transmission axis that transmits only light polarized in a specific direction and reflects light polarized in a direction orthogonal to the transmission axis. As the reflective polarizing plate 3 of the liquid crystal display element 1 of the present embodiment, a commercially available one can be used, for example, a reflective polarizing plate such as DBEF (registered trademark) series by Sumitomo 3M Limited. Can do.

  The transmission axis and reflection axis of the reflective polarizing plate 3 are preferably set so that the transmission axis is orthogonal to the F polarizing plate 5. In that case, the reflection axis of the reflective polarizing plate 3 is set in a direction parallel to the transmission axis of the F polarizing plate 5.

  A backlight 2 is arranged on the back side of the reflective polarizing plate 3 of the liquid crystal display element 1 of the present embodiment. Further, instead of the backlight 2, it is also possible to arrange another liquid crystal display element with a backlight, a light emitting display element, or the like. When the backlight 2 is disposed, the liquid crystal display element 1 uses light from the backlight 2 for displaying character information and the like in the display area. Further, when another liquid crystal display element with a backlight or the like is arranged, an image provided therefrom is used as an image display in the display area.

  When the liquid crystal display element 1 uses another liquid crystal display element with a backlight, the transmission axis of the reflective polarizing plate 3 and the polarizing plate on the front side that is the viewer side of the other liquid crystal display element with a backlight are shown. It is preferable to arrange in parallel with the transmission axis.

  As a liquid crystal display element with a backlight, a TFT (Thin Film) of at least one liquid crystal mode selected from the group consisting of a TN mode, an STN (Super Twisted Nematic) mode, an IPS mode, a VA mode, and an OCB (Optically Compensated Birefringence) mode. Preferably, the transistor is an active matrix liquid crystal display element. When a light emitting display element is used, an organic EL display (OLED: Organic Light Emitting Diode), a fluorescent display tube (VFD: Vacuum Fluorescent Display), or the like can be used.

  About the liquid crystal display element 1 of this embodiment which has the above structure, the effect in the case where a viewer wears and sees polarized glasses such as sunglasses having a transmission axis in the vertical direction will be described.

  In the liquid crystal display element 1, the light from the viewer side, that is, the light including information such as the scenery behind the viewer, is applied when no voltage is applied or when an OFF voltage is applied to the mirror region and the display region. It passes through the transmission axis of the polarizing plate 5 and becomes linearly polarized light, and also passes through the liquid crystal layer of the liquid crystal panel 4. And since it is parallel to the reflection axis of the reflective polarizing plate 3, it is reflected, and since it passes through the liquid crystal layer and the F polarizing plate 5 as linearly polarized light, the mirror state can be confirmed without lowering the reflectivity.

  Then, when an ON voltage is applied in the mirror area and the display area, the alignment of the liquid crystal in the liquid crystal layer changes. Then, the linearly polarized light that has passed through the transmission axis of the F polarizing plate 5 becomes linearly polarized light or elliptically polarized light that is rotated by the birefringence of the liquid crystal layer of the liquid crystal panel 4, and deviates from the reflection axis direction of the reflective polarizing plate 3. As a result, the reflectance decreases. In the liquid crystal display element 1, the decrease in reflectance at the reflective polarizing plate 3 is utilized as an antiglare function.

  On the other hand, in the liquid crystal display element 1, the light from the backlight 2 passes through the transmission axis of the reflective polarizing plate 3 when no voltage is applied or when an OFF voltage is applied, and becomes a linearly polarized light. pass. However, since it is perpendicular to the transmission axis of the F polarizing plate 5, the light from the backlight 2 is shielded by the F polarizing plate 5.

  When an ON voltage is applied in the mirror region and the display region, the light passes through the transmission axis of the reflective polarizing plate 3 and becomes linearly polarized light. Due to the birefringence of the liquid crystal layer of the liquid crystal panel 4, the linearly polarized light or ellipse rotated by the linearly polarized light. It becomes polarized light. As a result, since the light from the backlight 2 is parallel to the transmission axis of the F-polarizing plate 5, bright transmitted light from the backlight 2 can be obtained in the liquid crystal display element 1. This transmitted light forms a display in the liquid crystal display element 1.

  In the liquid crystal display element 1 of the present embodiment having the above functions, the mirror region as the first region and the display region as the second region are controlled independently, and particularly the birefringence of the liquid crystal layer. Is controlled. The liquid crystal display element 1 exhibits a mirror function in the mirror region, and further enables the anti-glare function to be exhibited in the mirror region, while the display region exhibits a display function for performing bright display. The liquid crystal display element 1 of the present embodiment can realize both the mirror function and the information display function and improve the visibility thereof.

  At this time, as described above, in the liquid crystal display element 1, the viewing angle direction can be set clockwise from the horizontal direction, for example, in the direction of 45 ° (so-called 4:30 viewing angle). Further, it is possible to set the direction from the horizontal direction clockwise, for example, in the direction of 135 ° (so-called 7:30 viewing angle) according to the direction of the viewer. Furthermore, when the liquid crystal display element 1 of the present embodiment is used as a vehicle fender mirror, a door mirror, or the like, a 45 ° direction (so-called 1:30 viewing angle) from the horizontal direction counterclockwise according to the direction of the viewer. ) Or 135 ° counterclockwise from the horizontal direction (so-called 10:30 viewing angle).

  Moreover, the liquid crystal display element 1 arranges gray printing, black printing, a light-shielding plate, etc. on the outside of the reflective polarizing plate 3 in the mirror area other than the display area, and from the back side that is the anti-viewer side. Therefore, the function as a mirror can be improved.

  The liquid crystal display element 1 has an anti-glare function using electrochromic or the like between the viewer and the F polarizing plate 5 so that the glare of the headlight of the following vehicle can be further reduced at night. May be installed.

  Furthermore, the liquid crystal display element 1 of the present embodiment is a first optical sensor (not shown) that senses light incident from the first surface of the first substrate of the liquid crystal panel 4, that is, the first direction facing the front surface side. And a second optical sensor (not shown) that senses light incident from the periphery of the liquid crystal panel 4 other than the first direction.

  Then, the control device (not shown) of the liquid crystal display element 1 described above compares, for example, the intensity of light sensed by the first optical sensor and the intensity of light sensed by the second optical sensor, and the mirror The birefringence of the liquid crystal layer of the liquid crystal panel 4 in the region can be controlled, and the reflection of light from the reflective polarizing plate 3 can be controlled. In the liquid crystal display element 1, it is preferable that the control using such an optical sensor is automatically performed.

  Still further, the liquid crystal display element 1 senses ambient brightness by the first and second photosensors, and is controlled between the second electrode and the fourth electrode in the display area by the control device according to the use situation. It is also possible to adjust the applied voltage and automatically adjust the transmittance. In that case, the brightness of the backlight 2 can be automatically adjusted.

Next, in the liquid crystal display element 1 of the present embodiment, the liquid crystal panel 4 is a vertical alignment type liquid crystal panel, but as described above, the liquid crystal in the TN (Twisted Nematic) mode or the IPS (In-Plane Switching) mode. It can also be a panel.
In particular, a highly reliable TN mode liquid crystal panel suitable for in-vehicle use can be obtained. Hereinafter, another example of the liquid crystal display element of the present embodiment using a TN mode liquid crystal panel as the liquid crystal panel will be described.

  In a liquid crystal display element which is another example of this embodiment, a liquid crystal panel sandwiching a liquid crystal layer constitutes a TN mode liquid crystal panel. At this time, the liquid crystal display element which is another example of the present embodiment uses a horizontal alignment liquid crystal alignment film as a liquid crystal alignment film of a liquid crystal panel, and uses a liquid crystal having positive dielectric anisotropy as a TN mode. To realize. And in the liquid crystal display element which is another example of this embodiment, it is preferable to make it the same as that of the liquid crystal display element 1 mentioned above other than having demonstrated especially below. Therefore, the same components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 6 is a schematic cross-sectional view showing the structure of a liquid crystal display element which is another example of the embodiment of the present invention.

  The liquid crystal display element 51 of another example of the embodiment of the present invention shown in FIG. 6 has the same rearview mirror-like appearance as the liquid crystal display element 100 illustrated in FIG. And having a mirror area (not shown) indicating a mirror state and a display area (not shown) for displaying character information and an image.

  As shown in FIG. 6, a liquid crystal display element 51 of another example of the present embodiment is configured by laminating a backlight 2, a reflective polarizing plate 3, a liquid crystal panel 54, and an F polarizing plate 5 in this order. That is, in the liquid crystal display element 51, the liquid crystal panel 54 is sandwiched between the F polarizing plate 5 disposed on the front side which is the viewer (not shown) side and the reflective polarizing plate 3 disposed on the back side. The On the back side of the liquid crystal panel 4, the backlight 2 is disposed on the back side of the reflective polarizing plate 3.

  The liquid crystal panel 54 is a transmissive liquid crystal panel. Each of the liquid crystal panels 54 is made of a light-transmitting material such as glass or resin, and a pair of substrates (not shown) including a first substrate disposed on the front side and a second substrate disposed on the back side. Is configured to sandwich a liquid crystal layer (not shown). In the liquid crystal panel 54, for example, the liquid crystal layer is sealed between the first substrate and the second substrate by a sealing material (not shown) provided at the peripheral edge.

  The 1st board | substrate of the liquid crystal panel 54 has a 1st electrode and a 2nd electrode in the 2nd surface used as the back side opposite to the 1st surface used as the front side (viewer side). The second substrate disposed opposite to the first substrate with the liquid crystal layer interposed therebetween has a third electrode facing the first electrode on the first surface facing the second surface of the first substrate, And a fourth electrode opposed to the second electrode. The liquid crystal layer includes a first surface of the first substrate on which the first electrode and the second electrode are disposed, and a first substrate on which the third electrode and the fourth electrode are disposed on the second substrate. It is sandwiched and arranged between the surface side.

  The first electrode and the second electrode on the first substrate, and the third electrode and the fourth electrode on the second substrate are each made of, for example, ITO (Indium Tin Oxide) or the like. A transparent electrode made of a transparent conductive material is preferable. Each electrode on the substrate is subjected to necessary patterning and formed into a desired shape. The shapes of the first electrode and the third electrode, and the second electrode and the fourth electrode of the liquid crystal panel 54 are formed so as to correspond to the shape of the mirror region in the liquid crystal display element 51 and the display pattern of the display region. can do. Further, the first electrode and the second electrode on the first substrate are segment electrodes, the third electrode and the fourth electrode on the second substrate are common electrodes, or the first electrode on the first substrate. The second electrode and the second electrode may be common electrodes, and the third and fourth electrodes on the second substrate may be segment electrodes.

  That is, in the liquid crystal display element 51 of another example of the present embodiment, the facing region between the first electrode and the third electrode of the liquid crystal panel 54 forms a mirror region as the first region, and the second electrode And the fourth electrode can form a display region as the second region. The liquid crystal display element 51 of another example of the present embodiment is a control device that can be driven to change the orientation of the liquid crystal in the liquid crystal layer independently in the first region and the second region of the liquid crystal panel 54. (Not shown). As described above, the liquid crystal display element 51 has a desired use of the mirror function and the display function so that one of the first region and the second region is a mirror region and the other is a display region. Is possible.

  In the liquid crystal panel 54, the second surface on which the first electrode and the second electrode of the first substrate are formed, and the first surface on which the third electrode and the fourth electrode of the second substrate are formed. Each surface is preferably provided with a liquid crystal alignment film (not shown) that is in contact with the liquid crystal layer and realizes a uniform initial alignment of the liquid crystal layer. The liquid crystal panel 54 preferably uses a horizontal alignment liquid crystal alignment film.

  The liquid crystal layer of the liquid crystal panel 54 of the present embodiment is formed using, for example, a nematic liquid crystal and has positive dielectric anisotropy.

  The liquid crystal layer of the liquid crystal panel 54 horizontally aligns the liquid crystal by forming a predetermined pretilt angle, for example, a pretilt angle of 0.5 ° to 10 °, between the first substrate and the second substrate. . Furthermore, an initial alignment state in which a twist alignment of 80 ° to 100 °, particularly preferably a twist alignment of 90 °, is performed between the first substrate and the second substrate.

  The initial alignment state of the liquid crystal in the liquid crystal layer of the liquid crystal panel 54 can be realized by subjecting the liquid crystal alignment film to alignment treatment in a certain direction such as rubbing treatment. For example, the liquid crystal alignment film on the first substrate on the front side of the liquid crystal panel 54 is subjected to an alignment process in the direction of 85 ° to 95 ° with respect to the horizontal direction, and the liquid crystal alignment film on the second substrate on the back side is The orientation treatment is preferably performed in the direction of −5 ° to + 5 ° clockwise with respect to the horizontal direction. As a result, the liquid crystal in the liquid crystal layer of the liquid crystal panel 54 is aligned so as to have a twist alignment of 80 ° to 100 ° between the first substrate and the second substrate. Further, the liquid crystal alignment film on the first substrate is aligned in the direction of −5 ° to + 5 ° clockwise with respect to the horizontal direction, and the liquid crystal alignment film on the second substrate is 85 ° to 95 with respect to the horizontal direction. Orientation treatment may be performed in the direction of °.

  As described above, the liquid crystal panel 54 preferably constitutes a TN mode liquid crystal panel. The TN mode liquid crystal panel 54 has excellent reliability and is suitable for the configuration of a rearview mirror and a display element of an automobile or the like.

  In another example of the liquid crystal display element 51 of the present embodiment, the transmission axis of the front side F polarizing plate 5 of the liquid crystal panel 54 is the transmission axis of polarized glasses such as sunglasses worn by the viewer. It is preferable to set in parallel directions. In the polarizing glasses, the transmission axis is normally set in the vertical direction (the direction perpendicular to the horizontal direction). Therefore, the transmission axis of the F-polarizing plate 5 is similarly set to be in the vertical direction. Is preferred.

  As described above, the reflective polarizing plate 3 on the back side of the liquid crystal panel 54 has a transmission axis that transmits only light polarized in a specific direction, and light polarized in a direction orthogonal to the transmission axis is It is a polarizing plate to be reflected. The transmission axis and reflection axis of the reflective polarizing plate 3 are preferably set so that the transmission axis is parallel to the F polarizing plate 5. In that case, the reflection axis of the reflective polarizing plate 3 is set in a direction orthogonal to the transmission axis of the F polarizing plate 5.

  The backlight 2 is disposed on the back side of the reflective polarizing plate 3 of the liquid crystal display element 51 of the present embodiment. Further, instead of the backlight 2, it is also possible to arrange another liquid crystal display element with a backlight, a light emitting display element, or the like. When the backlight 2 is disposed, the liquid crystal display element 51 uses the light from the backlight 2 for displaying character information and the like in the display area. Further, when another liquid crystal display element with a backlight or the like is arranged, an image provided therefrom is used as an image display in the display area.

  When the liquid crystal display element 51 uses another liquid crystal display element with a backlight, the transmission axis of the reflective polarizing plate 3 and the polarizing plate on the front side that is the viewer side of the other liquid crystal display element with a backlight are shown. It is preferable to arrange in parallel with the transmission axis.

  As a liquid crystal display element with a backlight, a TFT (Thin Film) of at least one liquid crystal mode selected from the group consisting of a TN mode, an STN (Super Twisted Nematic) mode, an IPS mode, a VA mode, and an OCB (Optically Compensated Birefringence) mode. Preferably, the transistor is an active matrix liquid crystal display element. When a light emitting display element is used, an organic EL display (OLED: Organic Light Emitting Diode), a fluorescent display tube (VFD: Vacuum Fluorescent Display), or the like can be used.

  With respect to the liquid crystal display element 51 of another example of the present embodiment having the above-described configuration, an effect when the viewer visually recognizes wearing polarized glasses such as sunglasses having a transmission axis in the vertical direction will be described.

  In the liquid crystal display element 51, the light from the viewer side, that is, the light including information such as the landscape behind the viewer, is applied when no voltage is applied or when an OFF voltage is applied to the mirror region and the display region. It passes through the transmission axis of the polarizing plate 5 and becomes linearly polarized light. Then, the light enters the liquid crystal layer of the liquid crystal panel 54 and becomes linearly polarized light whose polarization axis is rotated by the optical rotation of the liquid crystal. As a result, since it is parallel to the reflection axis of the reflective polarizing plate 3, it is reflected, and it is rotated by the liquid crystal layer and passes through the F polarizing plate 5 as linearly polarized light. I can confirm.

  When the ON voltage is applied in the mirror region and the display region, the orientation of the liquid crystal layer changes. Then, the linearly polarized light that has passed through the transmission axis of the F-polarizing plate 5 also passes through the liquid crystal layer of the liquid crystal panel 54, but the reflectance decreases because the polarization axis deviates from the direction of the reflection axis of the reflective polarizing plate 3. In the liquid crystal display element 51, the decrease in the reflectance at the reflective polarizing plate 3 is utilized as an antiglare function.

  On the other hand, in the liquid crystal display element 51, the light from the backlight 2 passes through the transmission axis of the reflective polarizing plate 3 when no voltage is applied or when an OFF voltage is applied, and becomes linearly polarized light. It becomes linearly polarized light whose polarization axis is rotated by optical rotation. However, since it is perpendicular to the transmission axis of the F polarizing plate 5, the light from the backlight 2 is shielded by the F polarizing plate 5.

  When an ON voltage is applied in the mirror region and the display region, the light from the backlight 2 passes through the transmission axis of the reflective polarizing plate 3 to become linearly polarized light, and passes through the liquid crystal layer of the liquid crystal panel 54. As a result, since the polarization axis of the light from the backlight 2 is parallel to the transmission axis of the F polarizing plate 5, bright transmitted light from the backlight 2 can be obtained in the liquid crystal display element 51. This transmitted light forms a display in the liquid crystal display element 51.

  In the liquid crystal display element 51 of the present embodiment having the above functions, the mirror area as the first area and the display area as the second area are independently controlled, and in particular, the rotation of the liquid crystal in the liquid crystal layer. Control sex. The liquid crystal display element 51 exhibits a mirror function in the mirror region, and further enables the anti-glare function to be exhibited in the mirror region, while the display region exhibits a bright display function. The liquid crystal display element 51 of the present embodiment can achieve both a mirror function and an information display function, and can improve the visibility thereof.

  At this time, as described above, in the liquid crystal display element 51, the viewing angle direction can be set clockwise from the horizontal direction, for example, in the direction of 45 ° (so-called 4:30 viewing angle). Further, it is possible to set the direction from the horizontal direction clockwise, for example, in the direction of 135 ° (so-called 7:30 viewing angle) according to the direction of the viewer. Furthermore, when the liquid crystal display element 51 of the present embodiment is used as a vehicle fender mirror, a door mirror, or the like, a 45 ° direction (so-called 1:30 viewing angle) from the horizontal direction counterclockwise depending on the direction of the viewer. ) Or 135 ° counterclockwise from the horizontal direction (so-called 10:30 viewing angle).

  Further, the liquid crystal display element 51 has a gray area, a black area, or a light-shielding plate disposed outside the reflective polarizing plate 3 in the mirror area other than the display area, and from the back side that is the anti-viewer side. Therefore, the function as a mirror can be improved.

  The liquid crystal display element 51 has an anti-glare function using electrochromic or the like between the viewer and the F polarizing plate 5 so that the glare of the headlight of the following vehicle can be further reduced at night. May be installed.

  Further, the liquid crystal display element 51 of the present embodiment is a first optical sensor (not shown) that senses light incident from a first direction opposite to the first surface of the first substrate of the liquid crystal panel 54, that is, the front surface side. And a second photosensor (not shown) that senses light incident from the periphery of the liquid crystal panel 54 except for the first direction.

  The control device (not shown) of the liquid crystal display element 51 described above compares, for example, the intensity of light sensed by the first optical sensor and the intensity of light sensed by the second optical sensor, and the mirror The optical rotation of the liquid crystal layer of the liquid crystal panel 54 in the region can be controlled, and the reflection of light from the reflective polarizing plate 3 can be controlled. In the liquid crystal display element 51, it is preferable that the control using such an optical sensor is automatically performed.

  Still further, the liquid crystal display element 51 senses ambient brightness by the first and second photosensors, and is controlled between the second electrode and the fourth electrode in the display region by the control device according to the use situation. It is also possible to adjust the applied voltage and automatically adjust the transmittance. In that case, the brightness of the backlight 2 can be automatically adjusted.

  Hereinafter, embodiments of the present invention will be described more specifically based on examples. However, the present invention is not limited to these examples.

Example 1.
In the present embodiment, a liquid crystal display element having both a function for displaying character information and a mirror function was manufactured. The liquid crystal display element of this embodiment is suitable for providing a rearview mirror having an information display function.

  FIG. 7 is a diagram showing the positional relationship of the optical axes of the respective components in the liquid crystal display element of the first embodiment of the present invention.

  In order to manufacture the liquid crystal display element 1000 of the first embodiment of the present invention, a pair of horizontally long and rectangular glass substrates with an ITO film were prepared. Then, using the glass substrate with the ITO film, a predetermined area corresponding to each area for forming a mirror area and for a display area for displaying information such as characters, figures and the like indicating temperature, clock or orientation, etc. A segmented electrode (not shown) and a common electrode (not shown) were patterned using a known method to form a substrate with electrodes.

Next, a vertical alignment liquid crystal alignment film (not shown) is formed on the electrode-attached substrate so as to cover the segment electrode and the common electrode in the mirror region and the display region, and is anti-parallel (anti-parallel) in a predetermined direction. (Parallel) was rubbed. After that, a liquid crystal panel 1004 of a vertical alignment type was manufactured by using a pair of rubbed substrates with electrodes and holding the liquid crystal so that the liquid crystal alignment film surface touches the liquid crystal (not shown). The pretilt angle of the liquid crystal (not shown) in the liquid crystal panel 1004 was 89.6 °, and the retardation (Δn _LC (refractive index anisotropy of liquid crystal) × d _LC (liquid crystal thickness)) was 300 nm. As the liquid crystal, a liquid crystal composition having a dielectric anisotropy (Δε) of −2.2 was used.

  In FIG. 7, the direction of rubbing processing in the liquid crystal panel 1004 is shown by using solid arrows and dotted arrows. The solid arrow indicates the direction of rubbing treatment on the front electrode-attached substrate, and the dotted arrow indicates the direction of rubbing treatment on the back-side electrode-attached substrate. As will be described later, the rubbing treatment direction is oriented from the reference axis when viewed from the front side, which is the viewer direction, on the substrate with electrodes on the front side when the long side direction of the liquid crystal panel 1004 is used as the reference axis. The clockwise angle to the treatment direction was set to 45 °.

  Next, the F polarizing plate 1005 was disposed on the front side which is the viewer side of the liquid crystal panel 1004, and the reflective polarizing plate 1003 was disposed on the back side which was the anti-viewer side, and the liquid crystal panel 1004 was sandwiched.

  As the F polarizing plate 1005, 040R140N-VH39L2S (Re (in-plane retardation) = 40 nm, Rth (thickness direction retardation) = 140 nm polarizing plate with an optical compensation film) manufactured by Polatechno Co., Ltd. was used. As the reflective polarizing plate 1003, DBEF (registered trademark) manufactured by Sumitomo 3M Limited was used.

  The settings of the transmission axes 1015 and 1013 of the F polarizing plate 1005 and the reflective polarizing plate 1003 were as follows. First, the long side direction of the liquid crystal panel 1004 was used as a reference axis. The liquid crystal display element 1000 can be installed and used so that the long side of the liquid crystal panel 1004 is horizontal. In that case, the reference axis is parallel to the horizontal direction.

  When the counterclockwise angle from this reference axis to the transmission axis 1015 of the F-polarizing plate 1005 when viewed from the front side in the viewer direction is θ1, θ1 = 90 °. When the counterclockwise angle from the reference axis to the transmission axis 1013 of the reflective polarizing plate 1003 is θ2, θ2 = 0 °. That is, the transmission axis 1013 of the reflective polarizing plate 1003 is set to be parallel to the reference axis. When the counterclockwise angle from the reference axis when viewed from the front side to the reflection axis 1016 of the reflective polarizing plate 1003 is θ3, θ3 = 90 °.

  Next, an ice blue LED was used as a backlight (not shown in FIG. 7), and it was disposed on the back side of the reflective polarizing plate 1003 to obtain a liquid crystal display element 1000.

  When the liquid crystal display element 1000 was used and static driving was performed using the segment electrode and the common electrode, a good mirror function and good information display could be confirmed. In other words, a good mirror display was obtained when the power was turned off in the mirror area. When a voltage was applied to the liquid crystal in that region with the power turned on, the reflectance was adjusted and an antiglare effect was obtained. In the display area, when the power was turned on, it was ice blue and bright information display such as temperature, clock, and direction corresponding to the shape of the segment electrode and common electrode in the display area could be confirmed.

  Furthermore, even when wearing sunglasses that are polarized glasses, the viewer was able to confirm a good mirror function in the mirror region and a good information display in the display region.

  Next, in the liquid crystal display element 1000, a first photosensor (not shown) that senses light incident from a first front direction facing the front side of the liquid crystal panel 1004 and the first direction are excluded. A second optical sensor (not shown) for sensing light incident from the periphery of the liquid crystal panel 1004 is provided. Then, using the liquid crystal display element 1000, the first photosensor and the second photosensor are provided, and the comparison result of the intensity of the light sensed by them is used. The voltage applied to the electrode was adjusted. Next, a usage environment was set in which strong light was incident from the front side while the surroundings were dark, such as a situation where the surroundings were dark at night and the headlights of the following cars were illuminated. In that case, a voltage could be applied between the segment electrode and the common electrode in the mirror region in accordance with the light sensing signals (information) from the first and second photosensors. At the same time, according to the voltage application, in the liquid crystal display element 1000, the mirror region has a brown to blue-violet hue, and the reflectivity of the mirror region can be reduced.

  That is, in the liquid crystal display element 1000, it was possible to improve visibility by automatically reducing the glare felt by the viewer due to the reflection according to the incident state of light from the surroundings.

Example 2
In the present example, a liquid crystal display element having both a mirror function and a function for displaying character information was manufactured as in the first example. The liquid crystal display element of this embodiment is suitable for providing a rearview mirror having an information display function.

  FIG. 8 is a diagram showing the positional relationship of the optical axes of the constituent elements in the liquid crystal display device according to the second embodiment of the present invention.

  In order to manufacture the liquid crystal display element 2000 of the second embodiment of the present invention, a pair of horizontally long and rectangular glass substrates with an ITO film were prepared. Then, using the glass substrate with the ITO film, a predetermined area corresponding to each area for forming a mirror area and for a display area for displaying information such as characters, figures and the like indicating temperature, clock or orientation, etc. A segmented electrode (not shown) and a common electrode (not shown) were patterned using a known method to form a substrate with electrodes.

  Next, a horizontal alignment liquid crystal alignment film (not shown) was formed on the electrode-attached substrate so as to cover the segment electrode and the common electrode in each of the mirror region and the display region. Each liquid crystal alignment film was subjected to alignment treatment (rubbing treatment). At this time, the liquid crystal alignment film on the substrate on the front side is aligned in a direction of 90 ° with respect to the horizontal direction, and the liquid crystal alignment film on the substrate on the back side is aligned in a direction parallel to the horizontal direction. It has been made. The direction of the alignment treatment on the substrate on the front side and the direction of the alignment treatment on the substrate on the back side form an angle of 90 °.

  At this time, the liquid crystal display element 2000 made of a rectangular glass substrate can be installed and used such that the long side of the glass substrate is horizontal. Therefore, an alignment process parallel to the horizontal direction is possible by performing an alignment process (rubbing process) so as to be parallel to the long side of the glass substrate. Further, by performing the alignment treatment in a direction that forms an angle of 90 ° with the long side of the glass substrate, the alignment treatment in the direction of 90 ° with respect to the horizontal direction can be performed.

Next, a liquid crystal panel 2004 was manufactured by sandwiching the liquid crystal so that the liquid crystal alignment film surface was in contact with the liquid crystal (not shown) using a pair of rubbed substrates with electrodes. As a result of the alignment treatment described above, the liquid crystal in the liquid crystal layer of the liquid crystal panel 2004 is aligned so as to have a 90 ° twist alignment between the front substrate and the rear substrate. At this time, the pretilt angle of the liquid crystal in the liquid crystal panel 2004 was 2 °. The retardation (Δn _LC (liquid crystal refractive index anisotropy) × d _LC (liquid crystal thickness)) of the liquid crystal layer was 600 nm. As the liquid crystal, a liquid crystal composition having a dielectric anisotropy (Δε) of +3.1 was used.

  In FIG. 8, a solid line arrow and a dotted line arrow are used to indicate the rubbing process direction in the liquid crystal panel 2004. The solid arrow indicates the direction of rubbing treatment on the front electrode-attached substrate, and the dotted arrow indicates the direction of rubbing treatment on the back-side electrode-attached substrate.

  Next, the F polarizing plate 2005 was disposed on the front side which is the viewer side of the liquid crystal panel 2004, and the reflective polarizing plate 2003 was disposed on the back side which is the anti-viewer side, so that the liquid crystal panel 2004 was sandwiched.

  As the F polarizing plate 2005, SWQ1423CUHC manufactured by Nitto Denko Corporation was used. As the reflective polarizing plate 2003, DBEF (registered trademark) manufactured by Sumitomo 3M Limited was used.

  The settings of the transmission axes 2015 and 2013 of the F polarizing plate 2005 and the reflective polarizing plate 2003 were as follows. First, the long side direction of the liquid crystal panel 2004 was used as a reference axis. The liquid crystal display element 2000 can be installed and used such that the long side of the liquid crystal panel 2004 is horizontal. In that case, the reference axis is parallel to the horizontal direction.

  When the counterclockwise angle from the reference axis to the transmission axis 2015 of the F-polarizing plate 2005 when viewed from the front side in the viewer direction is θ1, θ1 = 90 °. When the counterclockwise angle from the reference axis to the transmission axis 2013 of the reflective polarizing plate 2003 is θ2, θ2 = 90 °. That is, the transmission axis 2013 of the reflective polarizing plate 2003 is set to be orthogonal to the reference axis. When the counterclockwise angle from the reference axis when viewed from the front side to the reflection axis 2016 of the reflective polarizing plate 2003 is θ3, θ3 = 0 °.

  Next, an ice blue LED was used as a backlight (not shown in FIG. 8), and it was disposed on the back side of the reflective polarizing plate 2003 to obtain a liquid crystal display element 2000.

  When the liquid crystal display element 2000 was used for static driving using the segment electrode and the common electrode, a good mirror function and good information display could be confirmed. In other words, a good mirror display was obtained when the power was turned off in the mirror area. When a voltage was applied to the liquid crystal in that region with the power turned on, the reflectance was adjusted and an antiglare effect was obtained. In the display area, when the power was turned on, it was ice blue and bright information display such as temperature, clock, and direction corresponding to the shape of the segment electrode and common electrode in the display area could be confirmed.

  Furthermore, even when wearing sunglasses that are polarized glasses, the viewer was able to confirm a good mirror function in the mirror region and a good information display in the display region.

  Next, in the liquid crystal display element 2000, a first optical sensor (not shown) that senses light incident from the first front direction facing the front side of the liquid crystal panel 2004 and the first direction are excluded. A second optical sensor (not shown) for sensing light incident from the periphery of the liquid crystal panel 2004 is attached. Then, using the liquid crystal display element 2000, the first optical sensor and the second optical sensor are provided, and the comparison result of the intensity of light sensed by them is used, and according to the situation, the segment electrode and the common electrode of the mirror region The voltage applied to the electrode was adjusted. Next, a usage environment was set in which strong light was incident from the front side while the surroundings were dark, such as a situation where the surroundings were dark at night and the headlights of the following cars were illuminated. In that case, a voltage could be applied between the segment electrode and the common electrode in the mirror region in accordance with the light sensing signals (information) from the first and second photosensors. At the same time, according to the voltage application, in the liquid crystal display element 2000, the mirror region has a black hue, and the reflectivity of the mirror region can be reduced.

  That is, in the liquid crystal display element 2000, according to the incident state of light from the surroundings, it was possible to automatically reduce the glare felt by the viewer due to the reflection and improve the visibility.

Example 3
In this embodiment, a liquid crystal display element with a backlight is used instead of the backlight of the liquid crystal display element 1000 of the first embodiment described above. And the liquid crystal display element which has a function which displays an image in a part of mirror, and was compatible in a mirror function and an image display function was manufactured. The liquid crystal display element of this embodiment is suitable for providing a rearview mirror having an image display function.

  As will be described later, the liquid crystal display element of this example uses a liquid crystal display element with a backlight instead of a backlight, and the shape of the segment electrode and the common electrode in the display area of the liquid crystal panel is different so as to correspond to it. Except for the above, the liquid crystal display element 1000 of the first embodiment has the same structure. Therefore, the same components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 9 is a diagram showing the positional relationship of the optical axes of the respective components in the liquid crystal display device of the third embodiment of the present invention.

  In order to manufacture the liquid crystal display element 3000 of the third embodiment of the present invention, a pair of horizontally long and rectangular glass substrates with an ITO film were prepared. Using the glass substrate with the ITO film, a segment electrode (not shown) and a common electrode (not shown) and a predetermined shape corresponding to each region are used for forming a mirror region and a display region for displaying image information. (Not shown) was patterned using a known method to form a substrate with electrodes.

Next, a vertical alignment liquid crystal alignment film (not shown) is formed on the electrode-attached substrate so as to cover the segment electrode and the common electrode in the mirror region and the display region, and is anti-parallel (anti-parallel) in a predetermined direction. (Parallel) was rubbed. After that, a liquid crystal panel 3004 of a vertical alignment type was manufactured by using a pair of rubbed substrates with electrodes and holding the liquid crystal so that the liquid crystal alignment film surface touched the liquid crystal (not shown). The pretilt angle of the liquid crystal in the liquid crystal panel 3004 was 89.6 °, and the retardation (Δn _LC (refractive index anisotropy of liquid crystal) × d _LC (liquid crystal thickness)) was 300 nm. As the liquid crystal, a liquid crystal composition having a dielectric anisotropy (Δε) of −2.2 was used.

  In FIG. 9, the direction of rubbing processing in the liquid crystal panel 3004 is shown by using solid arrows and dotted arrows. The solid arrow indicates the direction of rubbing treatment on the front electrode-attached substrate, and the dotted arrow indicates the direction of rubbing treatment on the back-side electrode-attached substrate. As will be described later, the rubbing treatment direction is oriented from the reference axis when viewed from the front side, which is the viewer direction, on the substrate with electrodes on the front side when the long side direction of the liquid crystal panel 3004 is used as the reference axis. The clockwise angle to the treatment direction was set to 45 °.

  Next, the F polarizing plate 1005 is disposed on the front side which is the viewer side of the liquid crystal panel 3004, and the reflective polarizing plate 1003 is disposed on the back side which is the non-viewer side, so that the liquid crystal panel 3004 is paired with a pair of polarizing plates. I pinched it.

  As the F polarizing plate 1005, 040R140N-VH39L2S (Re (in-plane retardation) = 40 nm, Rth (retardation in the thickness direction) = 140 nm polarizing plate with an optical compensation film) manufactured by Polatechno Co., Ltd. was used. As the reflective polarizing plate 1003, DBEF (registered trademark) manufactured by Sumitomo 3M Limited was used.

  The settings of the transmission axes 1015 and 1013 of the F polarizing plate 1005 and the reflective polarizing plate 1003 were as follows. First, the long side direction of the liquid crystal panel 3004 was used as a reference axis. The liquid crystal display element 3000 can be installed and used so that the long side of the liquid crystal panel 3004 is horizontal. In that case, the reference axis is parallel to the horizontal direction.

  When the counterclockwise angle from this reference axis to the transmission axis 1015 of the F-polarizing plate 1005 when viewed from the front side in the viewer direction is θ1, θ1 = 90 °. When the counterclockwise angle from the reference axis to the transmission axis 1013 of the reflective polarizing plate 1003 is θ2, θ2 = 0 °. That is, the transmission axis 1013 of the reflective polarizing plate 1003 is set to be parallel to the reference axis. When the counterclockwise angle from the reference axis when viewed from the front side to the reflection axis 1016 of the reflective polarizing plate 1003 is θ3, θ3 = 90 °.

  Next, a liquid crystal display element 3000 was manufactured by using a liquid crystal display element 4000 with a backlight and disposing it on the back side of the R polarizing plate 1003. The backlight-equipped liquid crystal display element 4000 is an active matrix IPS mode liquid crystal display element driven by a TFT.

  The liquid crystal display element 4000 with a backlight includes a liquid crystal panel 4001 constituting an IPS mode sandwiched between a polarizing plate 4002 on the front side and a polarizing plate 4003 on the back side, and a backlight 4004 is disposed on the back side of the polarizing plate 4003. Composed. The transmission axis 4012 of the polarizing plate 4002 and the transmission axis 4013 of the polarizing plate 4003 were set to be orthogonal to each other. The transmission axis 1013 of the R polarizing plate 1003 and the transmission axis 4012 of the polarizing plate 4002 on the front surface side of the backlight-equipped liquid crystal display element 4000 were set to be parallel to each other.

  When the liquid crystal display element 3000 was statically driven using the segment electrode and the common electrode, a good mirror function and a good image display from the backlit liquid crystal display element 4000 were confirmed. In other words, a good mirror display was obtained when the power was turned off in the mirror area. When a voltage was applied to the liquid crystal in that region with the power turned on, the reflectance was adjusted and an antiglare effect was obtained. In the display area, when the power was turned on, it was possible to confirm image display such as a bright moving image formed by the backlit liquid crystal display element 4000.

  Furthermore, the viewer could confirm a good mirror function and a good image display even when wearing sunglasses as polarizing glasses.

  Next, in the liquid crystal display element 3000, a first optical sensor (not shown) for sensing light incident from a first front direction facing the front side of the liquid crystal panel 3004 and the first direction are excluded. A second photosensor (not shown) for sensing light incident from the periphery of the liquid crystal panel 3004 is provided. Then, using the liquid crystal display element 3000, the first optical sensor and the second optical sensor are provided, and the comparison result of the intensity of light sensed by them is used, and the segment electrode and the common in the mirror region are used depending on the situation. The voltage applied to the electrode was adjusted. Next, a usage environment was set in which strong light was incident from the front side while the surroundings were dark, such as a situation where the surroundings were dark at night and the headlights of the following cars were illuminated. In that case, a voltage could be applied between the segment electrode and the common electrode in the mirror region in accordance with the light sensing signals (information) from the first and second photosensors. At the same time, according to the voltage application, in the liquid crystal display element 3000, the mirror area changed from brown to blue-violet, and the reflectivity of the mirror area could be reduced.

  That is, in the liquid crystal display element 3000, it was possible to automatically improve the visibility by reducing the glare felt by the viewer by the reflection according to the incident state of light from the surroundings.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in each of the above-described embodiments, it is exemplified that the transmission axis of polarized glasses such as sunglasses worn by the viewer is set in the vertical direction, but in the present invention, the transmission axis setting of polarized glasses is set up and down. It is not limited to the direction. For example, even when the transmission axis of the polarizing glasses is set in the horizontal direction, the optical axis setting of each component of the liquid crystal display element can be changed to correspond to it. That is, the transmission axis of the F-polarizing plate on the front side which is the viewer side is arranged so as to be parallel to the transmission axis of the polarizing glasses, and the optical components of other components such as the reflective polarizing plate are corresponding to it. The liquid crystal display element of the present invention can be provided by arranging the axes in the same optimal arrangement as described above. And the liquid crystal display element of this invention can have a display element function and a mirror function, and can also have an anti-glare function.

  Further, in the present invention, for example, a liquid crystal panel constituting a liquid crystal display element includes an active matrix liquid crystal panel capable of being driven at a low voltage by providing a switching element such as a TFT for each pixel together with electrodes constituting each pixel. It is also possible to do.

  The liquid crystal display element of the present invention is suitable as a display element for a portable information device having a mirror function, such as a mobile phone having a mirror function, in addition to a rearview mirror for a vehicle such as an automobile, assuming use outside. Can be used.

1, 51, 100, 200, 200 ′, 1000, 2000, 3000 Liquid crystal display element 2, 4004 Backlight 3, 1003, 2003 Reflective polarizing plate 4, 54, 1004, 2004, 3004, 4001 Liquid crystal panel 5, 1005, 2005 F polarizing plate 7, 1007 retardation plate 101, 201, 201 ′ mirror region 102, 202, 202 ′ display region 203, 203 ′, 1016, 2016 reflection axis 204, 204 ′, 211, 1013, 1015, 2013, 2015 , 4012, 4013 Transmission axis 210 Polarized glasses 4000 Liquid crystal display element with backlight 4002, 4003 Polarizing plate

Claims (4)

A first substrate having a first electrode and a second electrode on a second surface on the back side opposite to the first surface on the front side;
A first electrode disposed opposite to the first substrate and facing a second surface of the first substrate, a third electrode facing the first electrode, and a second electrode facing the first electrode A second substrate having a fourth electrode;
A liquid crystal layer sandwiched between a second surface side of the first substrate and a first surface side of the second substrate; a polarizing plate disposed on the first surface side of the first substrate; ,
A reflective polarizing plate that is disposed on the second surface side, which is the back side of the second substrate, and reflects light polarized in a direction perpendicular to the transmission axis;
A backlight disposed on the back side of the reflective polarizing plate,
A liquid crystal display element in which a facing region between the first electrode and the third electrode forms a first region, and a facing region between the second electrode and the fourth electrode forms a second region Because
The liquid crystal of the liquid crystal layer has negative dielectric anisotropy,
A vertical alignment liquid crystal alignment film in contact with the liquid crystal layer is provided on each of the second surface of the first substrate and the first surface of the second substrate, and the liquid crystal alignment film is a liquid crystal of the liquid crystal layer. Is oriented in the direction of 35 ° to 55 ° with respect to the horizontal direction orthogonal to the up-down direction so that is vertically aligned with a pretilt angle,
The polarizing plate is arranged so that its transmission axis is in the direction of 35 ° to 55 ° with the direction of the alignment treatment of the liquid crystal alignment film,
The reflective polarizing plate is arranged so that its transmission axis is orthogonal to the transmission axis of the polarizing plate,
The first region and the second region are independent of each other by applying a voltage between the first electrode and the third electrode and between the second electrode and the fourth electrode. In addition, the liquid crystal display element is configured to control the reflection of light from the reflective polarizing plate and the transmission of light from the backlight by changing the orientation of the liquid crystal. The liquid crystal display element according to claim 1, wherein a liquid crystal display element with a backlight or a light emitting display element is disposed instead of the backlight . A first photosensor for sensing light incident from a first direction facing the first surface of the first substrate; and a second photosensor for sensing light incident from the outside of the first direction. And comparing at least the intensity of light sensed by the first photosensor and the intensity of light sensed by the second photosensor, and at least of the first region and the second region On the other hand, the liquid crystal display element according to claim 1 , wherein the control of the reflection of light from the reflective polarizing plate is performed . The first region becomes a mirror region using light reflection from the reflective polarizing plate, and changes the orientation of the liquid crystal by applying a voltage between the first electrode and the third electrode. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is configured to control reflection of light from the reflective polarizing plate .

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