JP2013190726A - Polarization switching device and image display device - Google Patents

Abstract

The present invention provides a polarization switching device that reduces crosstalk generated at a separation portion between a plurality of electrodes.
The polarization direction of linearly polarized incident light L1 incident on a plurality of spaced apart electrodes 24 and liquid crystal molecules facing the electrodes 24 without applying a voltage to the electrodes 24 is rotated by 90 degrees. And a liquid crystal layer 21 that transmits the polarization direction without rotation by the liquid crystal molecules facing the separation portion 42 and transmits the electrode 24 without rotation while the predetermined voltage is applied. 2 and a plurality of electrodes 34 arranged alternately with the electrode 24, and the polarization direction of the linearly polarized light L2 incident on the liquid crystal molecules facing the electrode 34 without applying a voltage to the electrode 34 is rotated by 90 degrees and transmitted. And a liquid crystal layer 31 that transmits the polarization direction without rotation by the liquid crystal molecules facing the separation portion 52 and transmits the polarization direction without rotation when a predetermined voltage is applied to the electrode 34. Provided with a door.
[Selection] Figure 1

Description

  The present invention relates to a polarization switching device and an image display device suitable for use when alternately switching polarization states.

  A system that displays stereoscopic images uses a single projector and switches the polarization direction of light emitted from the projector alternately for the left eye and for the right eye, so that the viewer's left eye and right eye can be separated. There is an image that can be seen (see, for example, Patent Document 1). In such a system, for example, a left-eye image and a right-eye image are alternately switched in a time division manner and emitted from one projector. Then, for example, linearly polarized light having one polarization direction output from the projector is incident on the polarization switching device. The polarization switching device alternately switches the polarization direction of the incident light in synchronization with the switching time between the left-eye image and the right-eye image on the projector side. And the emitted light of this polarization switching device is projected on a predetermined screen. The viewer can see the left-eye image and the right-eye image separately with the left and right eyes by wearing glasses with analyzers with different polarization directions on the left and right sides and observing the light reflected on the screen. .

  FIG. 15 is a diagram illustrating a configuration example of a stereoscopic image display system as described above. The stereoscopic image display system shown in FIG. 15 includes one projector 100 and a polarization switching device 200 that switches the polarization direction of linearly polarized light emitted from the projector 100. The projector 100 switches the left-eye image and the right-eye image alternately and emits them in a time-sharing manner. At that time, the projector 100 uses the left-eye image light and the right-eye for the linearly polarized light in one polarization direction with the polarization direction being the vertical direction (that is, the 90 ° direction when the horizontal direction in FIG. 15 is 0 ° or 180 °). The image light is emitted. Then, the polarization switching device 200 receives the linearly polarized light emitted from the projector 100 and rotates the polarization direction of the incident linearly polarized light by 90 ° or without rotating. The polarization direction switching by the polarization switching device 200 is performed in synchronization with the time division switching time between the left-eye image and the right-eye image in the projector 100. The outgoing light whose polarization direction has not been rotated by the polarization switching device 200 remains linearly polarized light whose polarization direction is vertical (that is, the polarization direction is 90 °), and outgoing light whose polarization direction has been rotated by 90 ° has a polarization direction. It becomes linearly polarized light in the horizontal direction (that is, the polarization direction is 180 °). In addition, the polarization switching device 200 can also switch the linearly polarized light into circularly polarized light after switching the polarization direction of the linearly polarized light. In this case, the emitted light is converted into right circularly polarized light or left circularly polarized light. As such a polarization switching device 200, for example, a device using liquid crystal as described in Patent Document 1 can be used.

JP 2009-122659 A

  By the way, the scanning method of the image emitted from the projector 100 shown in FIG. 15 includes a surface scanning method for rewriting an image in units of frames and a line scanning method for sequentially rewriting an image for each horizontal line. FIG. 16 is a time chart showing a difference in display state between the left-eye image and the right-eye image due to a difference in scanning method. In FIG. 16, the left-eye image is shown as a shaded rectangle as an L image, and the right-eye image is shown as a white rectangle as an R image. In the surface scanning method, the left-eye image and the right-eye image are alternately switched at times t1, t2, and t3. Therefore, the polarization switching device 200 switches the polarization direction in synchronization with the times t1, t2, and t3 at which the left-eye image and the right-eye image are alternately switched.

  On the other hand, in the line scanning method, for example, scanning of a new left eye image is started at time t1, and then the right eye image is sequentially rewritten with the left eye image. Further, scanning of the next right-eye image is started from time t2, and the left-eye image is sequentially rewritten to the right-eye image. As described above, in the line scanning method, for example, in the first half of the period from time t1 to time t2 and the first half of the period from time t2 to time t3, the left-eye image and the right-eye image are mixed in one screen. It will be. Therefore, if the polarization direction switching by the polarization switching device 200 is performed in units of screens at times t1, t2, and t3, as in the case of the surface scanning method, a part of the left eye image and a part of the right eye image are obtained. It is converted into an incorrect polarization direction, and crosstalk occurs between the image for the left eye and the image for the right eye.

  As a countermeasure against crosstalk that occurs in the line scanning method described with reference to FIG. 16, for example, switching of the polarization direction in the polarization switching device 200 is performed in units of one horizontal scanning line (or in synchronization with image scanning). There has been proposed a method in which partial execution is performed in units of a fixed number of horizontal scanning lines). For example, in the polarization switching device 200, an electrode for applying a voltage to the liquid crystal layer is composed of a plurality of rectangular electrodes 211 to 215 as shown in FIG. 17, and the polarization direction is switched sequentially in synchronization with the line scanning. To. According to this configuration, it is possible to reduce the region where the polarization direction is set in the wrong direction, and thus it is possible to reduce the occurrence of crosstalk between the left eye image and the right eye image. Here, FIG. 17 is a diagram schematically showing the arrangement of a plurality of electrodes in the polarization switching device 200, and is a front view seen from the incident direction of incident light. In the polarization switching device 200, the electrodes 211 to 215 are arranged across a predetermined separation portion (that is, a region where there is no electrode between the electrodes) 221 to 224. In such a polarization switching device 200, the polarization direction is switched by sequentially applying or not applying a predetermined voltage to the electrodes 211 to 215.

  However, when the polarization switching device 200 is configured using a plurality of electrodes as shown in FIG. 17, no voltage is applied to the spacing portions 221 to 224 between the electrodes. Therefore, even if the voltage applied to the electrodes 211 to 215 is changed, the applied voltage does not change in the separation portions 221 to 224. Accordingly, the polarization directions cannot be switched by the separating portions 221 to 224, and crosstalk occurs due to this. That is, the polarization direction of the emitted light when no voltage is applied is the same in all of the electrodes 211 to 215 and the separating portions 221 to 224 as indicated by arrows in FIG. On the other hand, the polarization direction of the emitted light when a voltage is applied is, for example, as shown by an arrow in FIG. That is, in the region corresponding to the shaded electrodes 211 to 215, the polarization direction changes in a direction different from that in the case of no voltage application shown in FIG. On the other hand, in the region corresponding to the separation portions 221 to 224, the polarization direction is the same as that shown in FIG. Accordingly, as shown in FIG. 19, when a voltage is applied, the polarization direction becomes an incorrect direction in a region corresponding to the separation portions 221 to 224, and crosstalk occurs.

  Note that FIGS. 15 to 19 referred to in the above description are created for the purpose of explaining the background art of the present invention by the present applicant.

  The present invention has been made in consideration of the above circumstances, and a polarization switching device capable of reducing crosstalk generated in a separation portion between electrodes when switching the polarization direction using a plurality of electrodes, and An object is to provide an image display device.

In order to solve the above-described problem, a polarization switching device of the present invention includes a plurality of first electrodes arranged with a space therebetween and liquid crystal molecules that generate birefringence, and uses the plurality of first electrodes. In the region where the voltage is applied, when the first electrode is in a predetermined first voltage application state, the polarization direction of the linearly polarized light incident through the liquid crystal molecules facing the first electrode is changed to 90. And when the first electrode enters a predetermined second voltage application state, the polarization direction of the incident linearly polarized light is changed through the liquid crystal molecules facing the first electrode. In the region where the light is transmitted without rotation and is opposed to the separation between the plurality of first electrodes and no voltage is applied, the light is incident through the liquid crystal molecules facing the separation between the plurality of first electrodes. First liquid crystal layer that transmits the polarization direction of linearly polarized light without rotation A first polarization switching unit having a plurality of electrodes arranged at a distance from each other, the electrodes being arranged at a position facing a separation portion of the plurality of first electrodes, and facing the first electrode A plurality of second electrodes whose positions are separated from each other and liquid crystal molecules that generate birefringence, and in a region where a voltage is applied using the plurality of second electrodes, the second electrode When the third voltage is applied, the polarization direction of the linearly polarized light incident from the first polarization switching element is transmitted through the liquid crystal molecules facing the second electrode by rotating by 90 degrees, and When the second electrode is in a predetermined fourth voltage application state, the polarization direction of the linearly polarized light incident from the first polarization switching element via the liquid crystal molecules facing the second electrode is not rotated. Transmissive and spaced apart between the plurality of second electrodes In a region where no directing voltage is applied, the polarization direction of the linearly polarized light incident from the first polarization switching element is transmitted without rotation through the liquid crystal molecules facing the separated portions between the plurality of second electrodes. And a second polarization switching means having two liquid crystal layers.

  According to the present invention, since the electrodes and the separation portions in the first polarization switching means and the second polarization switching means are alternately combined, the linearly polarized light transmitted through the separation portion of one polarization switching means is changed. It becomes possible to rotate the polarization direction by 90 degrees at the electrode portion of the other polarization switching means. Therefore, by switching the polarization direction of the linearly polarized light that passes through the electrode part, the polarization direction of the linearly polarized light that passes through the separated part can also be switched, and the crosstalk generated at the separated part between the electrodes without any discrepancy in the polarization direction. Can be reduced.

  In another aspect of the polarization switching device of the present invention, the polarization direction of the linearly polarized light incident on the first polarization switching element is an alignment axis of liquid crystal molecules facing the separation portion between the first electrodes. It is characterized by being parallel or orthogonal to the direction of the alignment axis of the liquid crystal molecules facing the direction and the spacing between the second electrodes.

  According to the present invention, for example, the liquid crystal molecules are opposed to the separation portion between the first electrodes and the separation portion between the second electrodes by making the alignment axis direction of the liquid crystal molecules parallel or perpendicular to the polarization direction of the incident light. It can be transmitted without rotation without changing the polarization direction of the incident light to the molecule.

  According to another aspect of the polarization switching device of the present invention, the polarization direction of the linearly polarized light incident on the first polarization switching element is a liquid crystal that faces the first electrode in the first voltage application state. The liquid crystal display device is characterized in that it is inclined 45 degrees with respect to the alignment axis direction of the liquid crystal molecules facing the second electrode in the molecular alignment axis direction and the third voltage application state.

  According to the present invention, the polarization direction of the linearly polarized light incident on the liquid crystal molecules facing the first electrode and the polarization direction of the linearly polarized light incident on the liquid crystal molecules facing the second electrode are both aligned with the liquid crystal molecules. It can be in the state inclined 45 degrees with respect to the axial direction.

  In another aspect of the polarization switching device of the present invention, the first voltage application state is a state in which no voltage is applied to the first electrode, and the second voltage application state is the first voltage application state. A predetermined voltage is applied to the electrode, the third voltage application state is a state in which no voltage is applied to the second electrode, and the fourth voltage application state is the second voltage application state. The electrode is in a state where a predetermined voltage is applied to the electrode.

  According to the present invention, a state in which a predetermined voltage is applied to both the first polarization switching unit and the second polarization switching unit, and a voltage to both the first polarization switching unit and the second polarization switching unit. The polarization direction can be switched by switching between the state in which no is applied.

  In another aspect of the present invention, the polarization switching device further includes a polarization element that converts linearly polarized light emitted from the second polarization switching element into circularly polarized light.

  According to the present invention, incident linearly polarized light can be converted into right-handed or left-handed circularly polarized light.

  The image display device of the present invention emits the first emitted light representing the first image and the second emitted light representing the second image different from the first image at a predetermined cycle in a time-sharing manner. An output device, and the polarization switching device according to any one of the above, wherein the output light of the output device is incident as linearly polarized light, and the first output light is emitted when the output device emits the first output light. When the polarization switching device is in the first voltage application state, the second polarization switching device is in the second voltage application state, and the emission device emits the second emission light, The first polarization switching device is in the third voltage application state, and the second polarization switching device is in the fourth voltage application state.

  According to the present invention, crosstalk between different images can be reduced, and two different images can be viewed separately.

  In another aspect of the image display device of the present invention, the first image is a left-eye image for stereoscopic viewing, and the second image is a right-eye image for stereoscopic viewing. It is characterized by.

  According to the present invention, it is possible to view a stereoscopic image by reducing crosstalk between the left-eye image and the right-eye image.

It is a schematic diagram which shows the cross-sectional structure seen from the side surface of one Embodiment of the polarization switching apparatus by this invention. It is a schematic diagram which shows the shape and example of arrangement | positioning with an electrode and a separation | spacing part at the time of seeing the polarization switching element 2 of FIG. 1 from the front. It is a schematic diagram which shows the shape and example of arrangement | positioning with an electrode and a separation | spacing part at the time of seeing the polarization switching element 3 of FIG. 1 from the front. It is a schematic diagram for demonstrating the example of a setting of the orientation axis direction of a liquid crystal molecule in the polarization switching apparatus 1 of FIG. It is a schematic diagram for demonstrating the operation example (when a voltage is not applied to the electrode 24) of the polarization switching element 2 of FIG. FIG. 6 is a schematic diagram for explaining an operation example of the polarization switching element 2 in FIG. 1 (when a voltage is applied to an electrode 24). FIG. 6 is a schematic diagram for explaining an operation example of the polarization switching element 3 in FIG. 1 (when no voltage is applied to an electrode 34). FIG. 7 is a schematic diagram for explaining an operation example of the polarization switching element 3 in FIG. 1 (when a voltage is applied to an electrode 34). It is a schematic diagram which shows the modification of the polarization switching apparatus 1 shown in FIG. It is a schematic diagram which shows the shape at the time of seeing the electrode 40 or 50 of FIG. 9 from the front. It is a schematic diagram which shows the cross-sectional structure seen from the side surface of other embodiment of the polarization switching apparatus by this invention. FIG. 12 is a schematic diagram for explaining an operation example of the polarizing element 4 of FIG. 11 (when no voltage is applied to the electrode 24 and the voltage 34). FIG. 12 is a schematic diagram for explaining an operation example of the polarizing element 4 of FIG. 11 (when a voltage is applied to the electrode 24 and the voltage 34). It is a figure which shows the structural example of embodiment of the image display apparatus by this invention. It is a figure for demonstrating the display system of the stereoscopic vision image as background art of this invention. FIG. 16 is a diagram for describing an image scanning method in the stereoscopic image display system of FIG. 15. It is a figure for demonstrating the structural example of the polarization switching apparatus 200 of FIG. It is a figure for demonstrating the operation example of the polarization switching apparatus 200 of FIG. It is a figure for demonstrating the operation example of the polarization switching apparatus 200 of FIG.

  Hereinafter, embodiments of a polarization switching device according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a cross-sectional configuration of a polarization switching device 1 as an embodiment of the present invention as viewed from the side. The polarization switching device 1 shown in FIG. 1 includes a polarization switching element 2 and a polarization switching element 3. The polarization switching element 2 and the polarization switching element 3 are liquid crystal optical elements that change the polarization state of incident light using the birefringence of the liquid crystal. In the present embodiment, the polarization switching element 2 receives incident light L1 that is linearly polarized light in a predetermined polarization direction, transmits the liquid crystal layer 21 and the like, and emits light L2. The polarization switching element 3 receives the light L2 emitted from the polarization switching element 2, transmits the liquid crystal layer 31 and the like, and emits the light L3.

  The polarization switching element 2 includes a liquid crystal layer 21 in which liquid crystal molecules are enclosed, and a glass substrate 22 and a glass substrate 23 that sandwich the liquid crystal layer 21. The glass substrate 22 and the glass substrate 23 are parallel to each other. On the liquid crystal layer 21 side of the glass substrate 22, a plurality of transparent electrodes (hereinafter simply referred to as “electrodes”) 24 are provided via a spacing portion 42. A plurality of electrodes 26 are provided on the glass substrate 23 side of the glass substrate 23 via the spacing portions 42. The plurality of electrodes 24 and the plurality of electrodes 26 are provided so as to face each other as shown in FIG. FIG. 2 is a diagram illustrating a facing relationship between the plurality of electrodes 24 and the plurality of electrodes 26 when the polarization switching element 2 is viewed from the front direction (that is, the incident direction of the incident light L1). In addition, the plurality of electrodes 24 and the plurality of electrodes 26 have a rectangular shape formed over the entire longitudinal direction of the polarization switching element 2 and are arranged in parallel with each other via the separation portion 42. The voltage application state of each of the plurality of electrodes 24 and the plurality of electrodes 26 can be controlled independently. For example, the scanning time of each horizontal line by the line scanning method as described with reference to FIG. In synchronism with this, in combination with the plurality of electrodes 34 and the electrode 36 of the polarization switching element 3, it is possible to sequentially switch to the voltage application state or the voltage non-application state for control.

  An alignment film 25 is formed on the liquid crystal layer 21 side of the plurality of electrodes 24. An alignment film 27 is formed on the liquid crystal layer 21 side of the plurality of electrodes 26. An alignment film 28 is formed on the liquid crystal layer 21 side of the separation portion 42 of the glass substrate 22. An alignment film 29 is formed on the liquid crystal layer 21 side of the separation portion 42 of the glass substrate 23. The direction of the alignment axis of the liquid crystal molecules in the region 41 facing the electrode 24 and the electrode 26 is set by the alignment film 25 and the alignment film 27. The alignment film 28 and the alignment film 29 set the direction of the alignment axis of the liquid crystal molecules in the region 43 facing the separation part 42 on the glass substrate 22 and the separation part 42 on the glass substrate 23. In the present embodiment, the direction of the alignment axis set by the alignment film 25 and the alignment film 27 and the direction of the alignment axis set by the alignment film 28 and the alignment film 29 are set differently. The alignment film 25, the alignment film 27, the alignment film 28, and the alignment film 29 can be formed by a manufacturing method such as mask exposure using a polarization exposure machine, for example.

  The polarization switching element 3 includes a liquid crystal layer 31 in which liquid crystal molecules are enclosed, and a glass substrate 32 and a glass substrate 33 that sandwich the liquid crystal layer 31. The glass substrate 32 and the glass substrate 33 are parallel to each other. On the liquid crystal layer 31 side of the glass substrate 32, a plurality of electrodes 34 are provided via the separation part 52. On the liquid crystal layer 31 side of the glass substrate 33, a plurality of electrodes 36 are provided via the separation part 52. The plurality of electrodes 34 and the plurality of electrodes 36 are provided to face each other as shown in FIG. FIG. 3 is a diagram illustrating a facing relationship between the plurality of electrodes 34 and the plurality of electrodes 36 when the polarization switching element 3 is viewed from the front direction (that is, the incident direction of the incident light L1 and the light L2). In addition, the plurality of electrodes 34 and the plurality of electrodes 36 have a rectangular shape formed over the entire longitudinal direction of the polarization switching element 3 and are arranged in parallel to each other via the separation portion 52. In addition, each electrode of the plurality of electrodes 34 and the plurality of electrodes 36 can independently control the voltage application state. As described above, for example, by the line scanning method described with reference to FIG. In synchronization with the scanning time of each horizontal line, a combination of a plurality of electrodes 24 and electrodes 26 included in the polarization switching element 2 can be sequentially switched to a voltage application state or a voltage non-application state for control.

  In the polarization switching device 1, the polarization switching element 2 and the polarization switching element 3 include a plurality of electrodes 24 and a plurality of electrodes 26, a plurality of electrodes 34 and a plurality of electrodes 36 in the front direction (that is, incident light L 1). And the direction of incidence of the light L2). That is, the electrode 24 and the electrode 26 of the polarization switching element 2 and the separation portion 52 of the polarization switching element 3 have the same shape and face each other. Further, the electrode 34 and the electrode 36 of the polarization switching element 3 and the separation portion 42 of the polarization switching element 2 have the same shape and face each other. The electrode 24 and the electrode 26 and the electrode 34 and the electrode 36 may have the same shape or different shapes.

  An alignment film 35 is formed on the liquid crystal layer 31 side of the plurality of electrodes 34. An alignment film 37 is formed on the liquid crystal layer 31 side of the plurality of electrodes 36. An alignment film 38 is formed on the liquid crystal layer 31 side of the separation portion 52 of the glass substrate 32. An alignment film 39 is formed on the liquid crystal layer 31 side of the separation portion 52 of the glass substrate 33. The direction of the alignment axis of the liquid crystal molecules in the region 51 facing the electrode 34 and the electrode 36 is set by the alignment film 35 and the alignment film 37. The alignment film 38 and the alignment film 39 set the alignment axis direction of the liquid crystal molecules in the region 53 facing the separation portion 52 on the glass substrate 32 and the separation portion 52 on the glass substrate 33. In the present embodiment, the direction of the alignment axis set by the alignment film 35 and the alignment film 37 and the direction of the alignment axis set by the alignment film 38 and the alignment film 39 are set different from each other. The alignment film 35, the alignment film 37, the alignment film 38, and the alignment film 39 can be formed by a manufacturing method such as mask exposure using a polarization exposure machine, for example.

  In the polarization switching device 1 in FIG. 1, the surface positions of the alignment film 25 on the electrode 24 and the alignment film 28 on the separation portion 42 (that is, the height from the glass substrate 22 or the like) are different. There may be. Further, although the surface positions of the alignment film 27 on the electrode 26 and the alignment film 29 on the separation portion 42 are different, they may be the same. The same applies to the alignment films 35, 37, 38 and 39 of the polarization switching element 3. q

  Next, referring to FIG. 4, the direction of the alignment axis of the liquid crystal molecules set by the alignment film 25 and alignment films 27 to 29 and the alignment film 35 and alignment films 37 to 39 in the polarization switching device 1 of FIG. An example will be described. FIG. 4 is a front view of the polarization switching element 2 and the polarization switching element 3 as seen from the direction of the incident light L1, and is a schematic diagram showing the orientation axis directions in the liquid crystal layer 21 and the liquid crystal layer 31. FIG. In FIG. 4 and other drawings, the incident light L1 is linearly polarized light perpendicular to the polarization switching device 1, and the polarization direction of the incident light L1 in this case is 90 °. Further, the direction of the alignment axis and the polarization direction of the linearly polarized light incident / exited are 0 °, 45 °, 90 °, 135 ° and 180 ° with arrows in FIG. 4 with reference to 90 ° which is the polarization direction of the incident light L1. A description will be made using what is shown as °.

  In the present application, the major axis direction of liquid crystal molecules such as smectic liquid crystal and nematic liquid crystal is called the alignment axis direction. This smectic liquid crystal, nematic liquid crystal, or the like exhibits birefringence that the refractive index in the direction parallel to the alignment axis direction is different from the refractive index in the direction perpendicular to the alignment axis direction. When polarized light is incident on a substance exhibiting birefringence, the refractive index of the fast axis and the slow axis differs depending on the incident angle, and a phase difference occurs between the respective polarized components. However, linearly polarized light incident along the alignment axis direction (optical axis direction) or linearly polarized light whose polarization direction is orthogonal or parallel to the alignment axis direction does not cause a phase difference in each polarization component. Therefore, for example, when a voltage is applied to the liquid crystal layer so that the incident direction of the incident light coincides with the alignment axis direction of the liquid crystal molecules, no phase difference occurs in each polarization component of the incident light, and no rotation occurs. It is emitted at. Further, for example, when the liquid crystal molecules in the liquid crystal layer 21 or the liquid crystal layer 31 are aligned so that the alignment axis direction is parallel to the glass substrate 22 or the glass substrate 32, the polarized light is parallel or orthogonal to the alignment axis direction. A linearly polarized light having a direction is emitted without rotation with no phase difference between the polarized components. On the other hand, when the polarization direction of linearly polarized light is inclined from the alignment axis direction, a phase difference is generated in each polarization component. The magnitude of the phase difference generated in each polarization component varies depending on the refractive index of the liquid crystal layer, the thickness of the liquid crystal layer, and the incident angle of incident light.

The alignment axis directions indicated by arrows A to D shown in FIG. 4 are the regions 41, 43, 51, and 53 in the liquid crystal layer 21 and the liquid crystal layer 31 when no voltage is applied to the liquid crystal layer 21 and the liquid crystal layer 31. The orientation axis direction of the liquid crystal molecules (the alignment direction of the optical axes of the liquid crystal molecules). When no voltage is applied to the electrodes 24, 26, 34, and 36, the polarization direction of the incident light L1 and the liquid crystal in the region 41 between the electrode 24 and the electrode 26 and the region 51 between the electrode 34 and the electrode 36 are displayed. The angle formed between the alignment axis direction of the molecules is 45 °, and the phase difference of each polarization component transmitted through the region 41 and the region 51 in the liquid crystal layer 21 and the liquid crystal layer 31 is λ / 2 (that is, 180 °). It is assumed that the liquid crystal layer 21 and the liquid crystal layer 31 are set. Here, λ represents one wavelength. On the other hand, when a voltage is applied to the electrodes 24, 26, 34 and 36, the alignment axis directions of the liquid crystal molecules in the regions 41 and 51 in the liquid crystal layer 21 and the liquid crystal layer 31 are perpendicular to the electrode surfaces. Arranged and coincides with the incident direction of the incident light L1. Therefore, in the voltage application state, the phase difference of each polarization component transmitted through the region 41 and the region 51 in the liquid crystal layer 21 and the liquid crystal layer 31 is 0 (that is, 0 °). That is, when a predetermined voltage is applied to the liquid crystal layer 21 and the liquid crystal layer 31 and the incident direction of the incident light L1 coincides with the alignment axis direction of the liquid crystal, the angle between the polarization direction of the incident light L1 and the alignment axis direction is irrelevant. In addition, no phase difference occurs in each polarization component transmitted through the regions 41 and 51 in the liquid crystal layer 21 and the liquid crystal layer 31 (that is, the polarization direction does not rotate).
In the region 43 between the facing separation portions 42 and the region 53 between the facing separation portions 52 in the liquid crystal layer 21 and the liquid crystal layer 31, regardless of whether or not voltage is applied to the electrodes 24, 26, 34 and 36, The angle formed between the polarization direction of the incident light L1 and the alignment axis direction of the liquid crystal molecules is 0 °.
Therefore, the phase difference of each polarization component of the incident light L1 transmitted through the region 43 and the region 53 in the liquid crystal layer 21 and the liquid crystal layer 31 is 0 (that is, 0 °). That is, when the polarization direction of the incident light L1 coincides with the alignment axis direction of the liquid crystal molecules regardless of whether or not a predetermined voltage is applied to the electrodes 24, 26, 34 and 36 of the liquid crystal layer 21 and the liquid crystal layer 31. In addition, no phase difference is generated in each polarization component transmitted through the regions 43 and 53 in the liquid crystal layer 21 and the liquid crystal layer 31 (that is, the polarization direction does not rotate).

  In FIG. 4, an arrow with a symbol A indicates the alignment axis direction of the liquid crystal molecules in the region 41 facing the electrode 24 and the electrode 26 of the polarization switching element 2 when no voltage is applied. Here, the alignment axis direction A of the region 41 is set to 135 ° which is the alignment direction of the alignment film 25 and the alignment film 27.

  Further, in FIG. 4, an arrow with a symbol B indicates the direction of the alignment axis of the liquid crystal molecules in the region 43 facing the separation portion 42 of the polarization switching element 2. Here, the alignment axis direction B of the region 43 is set to 90 °, which is the alignment direction of the alignment film 28 and the alignment film 29.

  In FIG. 4, an arrow with a symbol C indicates the alignment axis direction of the liquid crystal molecules in the region 51 facing the electrodes 34 and 36 of the polarization switching element 3 when no voltage is applied. Here, the alignment axis direction C of the region 51 is set to 45 °, which is the alignment direction of the alignment film 35 and the alignment film 37.

  In FIG. 4, an arrow with a symbol D indicates the alignment axis direction of the liquid crystal molecules in the region 53 facing the separation portion 52 of the polarization switching element 3. Here, the alignment axis direction D of the region 53 is set to 90 ° which is the alignment direction of the alignment film 38 and the alignment film 39.

  Next, an operation example of the polarization switching device 1 in FIG. 1 will be described with reference to FIGS. In addition, the voltage application state between the plurality of electrodes 24 and the plurality of electrodes 26 and the voltage application state between the plurality of electrodes 34 and the plurality of electrodes 36 are sequentially controlled independently for each electrode in the line scanning method. . However, here, in order to simplify the description, the case where the voltage application state of each electrode is simultaneously switched to the application state or the non-application state (that is, the case of the surface scanning method) will be described as an example. FIG. 5 is a schematic diagram showing a state of the incident light L1 of the polarization switching element 2 and the light L2 emitted from the polarization switching element 2, and a voltage is applied between the electrode 24 and the electrode 26 facing the region 41. It shows the case of not. FIG. 6 is a schematic diagram illustrating a state of the incident light L1 of the polarization switching element 2 and the light L2 emitted from the polarization switching element 2, and a predetermined voltage is applied between the electrode 24 and the electrode 26 facing the region 41. The case where is applied is shown. FIG. 7 is a schematic diagram showing a state of the light L2 incident on the polarization switching element 3 and the outgoing light L3, and shows a case where no voltage is applied between the electrode 34 and the electrode 36 facing the region 51. Yes. FIG. 8 is a schematic diagram showing the state of the light L2 incident on the polarization switching element 3 and the outgoing light L3, and a predetermined voltage is applied between the electrode 34 and the electrode 36 facing the region 51. Shows the case.

  In the polarization switching device 1 of the present embodiment, the polarization direction of the incident light L1 is rotated by 90 ° and the linearly polarized outgoing light L3 having a polarization direction of 180 ° is emitted, and the polarization direction is not rotated as it is. Control is performed to switch between the case where the light is emitted as linearly polarized outgoing light L3 having a polarization direction of 90 °. When the polarization direction is rotated by 90 °, both the polarization switching element 2 and the polarization switching element 3 are controlled so that no voltage is applied (that is, no voltage is applied). On the other hand, when the polarization direction is not rotated, both the polarization switching element 2 and the polarization switching element 3 are controlled to be in a state where a voltage is applied (that is, a voltage application state).

  Therefore, when the polarization direction of the incident light L1 is rotated by 90 °, the operation state is a combination of FIG. 5 and FIG. On the other hand, when the polarization direction of the incident light L1 is not rotated, the operation state is a combination of FIGS. 6 and 8 in the voltage application state. 7 or 8 showing the operation state of the polarization switching element 3 shows an operation example when the outgoing light emitted from the polarization switching element 2 is incident in the corresponding operation state shown in FIG. 5 or FIG. ing.

  In the example shown in FIG. 5, no voltage is applied between the electrode 24 and the electrode 26, that is, no voltage is applied. In this case, the linearly polarized incident light L1 having a polarization direction of 90 ° is 45 ° with respect to the alignment axis direction A because the alignment axis direction A of the liquid crystal molecules in the region 41 facing the electrodes 24 and 26 is 135 °. The light is incident on the region 41 with a polarization direction having an inclination angle of. Further, in the region 41, when no voltage is applied between the electrode 24 and the electrode 26, the polarization direction of linearly polarized light that is incident with a polarization direction having an inclination angle of 45 ° with respect to the alignment axis direction A is rotated by 90 °. Then exit. Therefore, the light L2Aoff that passes through the region 41 and exits from the polarization switching element 2 is linearly polarized light having a polarization direction of 0 ° (or 180 °). That is, in the region 41, the linearly polarized incident light L1 in the vertical direction is converted into the linearly polarized light L2Aoff in the horizontal direction.

  In the region 43 facing the separation portion 42, the 90 ° orientation axis direction B is parallel to the polarization direction 90 ° of the linearly polarized incident light L1. Accordingly, no phase difference occurs in each polarization component of the linearly polarized incident light L1, and the linearly polarized light L2Boff having a polarization direction of 90 ° is emitted from the region 43 as it is.

  On the other hand, the example shown in FIG. 6 is a case where a predetermined voltage is applied between the electrode 24 and the electrode 26. That is, the voltage is applied. In this case, the alignment axis direction A of the region 41 facing the electrodes 24 and 26 coincides with, for example, the incident direction of the incident light L1. Therefore, no phase difference occurs in each polarization component of the linearly polarized incident light L1, and the linearly polarized light L2Aon having a polarization direction of 90 ° is emitted from the region 41 as it is.

  In the region 43 facing the separation portion 42, the 90 ° orientation axis direction B is parallel to the polarization direction 90 ° of the linearly polarized incident light L1. Therefore, no phase difference occurs in each polarization component of the linearly polarized incident light L1, and the linearly polarized light L2Bon having a polarization direction of 90 ° is emitted from the region 43 as it is.

  On the other hand, the example shown in FIG. 7 is a case where no voltage is applied between the electrode 34 and the electrode 36, that is, no voltage is applied. In this case, the light L2 emitted from the polarization switching element 2 in the no-voltage application state shown in FIG. That is, the linearly polarized light L2Aoff having a polarization direction of 0 ° (or 180 °) shown in FIG. In addition, linearly polarized light L2Boff having a polarization direction of 90 ° is incident on the region 51 facing the electrode 34 and the electrode 36.

  In this case, in the region 53 facing the separating portion 52, the 90 ° orientation axis direction D is orthogonal to the polarization direction 0 ° (or 180 °) of the linearly polarized light L2Aoff. Accordingly, no phase difference occurs in each polarization component of the linearly polarized light L2Aoff, and the linearly polarized outgoing light L3Doff having a polarization direction of 0 ° (or 180 °) is emitted from the region 53 as it is.

  The linearly polarized light L2Boff having a polarization direction of 90 ° is polarized light having an inclination angle of 45 ° with respect to the alignment axis direction C because the alignment axis direction C of the region 51 facing the electrodes 34 and 36 is 45 °. It enters the region 51 in the direction. Further, in the region 41, when no voltage is applied between the electrode 34 and the electrode 36, the polarization direction of linearly polarized light that is incident with a polarization direction having an inclination angle of 45 ° with respect to the alignment axis direction C is rotated by 90 °. Then exit. Therefore, the outgoing light L3Coff in the region 51 is linearly polarized light whose polarization direction is 0 ° (or 180 °). That is, in the region 51, the linearly polarized light L2Boff in the vertical direction is converted into the outgoing light L3Coff in the horizontal direction.

  On the other hand, the example shown in FIG. 8 is a case where a predetermined voltage is applied between the electrode 34 and the electrode 36, that is, a voltage application state. In this case, the light L2 emitted from the polarization switching element 2 in the voltage application state shown in FIG. That is, the linearly polarized light L2Aon having a polarization direction of 90 ° shown in FIG. In addition, linearly polarized light L2Bon having a polarization direction of 90 ° is incident on the region 51 facing the electrode 34 and the electrode 36. In this case, the alignment axis direction C of the region 51 facing the electrode 34 and the electrode 36 coincides with the incident direction of the light L2Bon incident on the region 51, for example. Accordingly, no phase difference occurs in each polarization component of the linearly polarized light L2Bon, and the linearly polarized outgoing light L3Con having a polarization direction of 90 ° is emitted from the region 51 as it is.

  Further, in the region 53 facing the separation portion 52, the 90 ° orientation axis direction D is parallel to the 90 ° polarization direction of the linearly polarized light L2Aon. Accordingly, no phase difference occurs in each polarization component of the linearly polarized light L2Aon, and the linearly polarized outgoing light L3Don having a polarization direction of 90 ° is emitted from the region 53 as it is.

  From the above, as shown in FIGS. 5 and 7, by controlling both the polarization switching element 2 and the polarization switching element 3 so that no voltage is applied (that is, no voltage application state), the polarization direction is 90 °. The linearly polarized incident light L1 can be converted into linearly polarized outgoing lights L3Doff and L3Coff whose polarization direction is 0 ° (or 180 °).

  Further, as shown in FIGS. 6 and 8, by controlling both the polarization switching element 2 and the polarization switching element 3 to a state where a predetermined voltage is applied (that is, a voltage application state), the polarization direction is 90 °. The linearly polarized incident light L1 can be output as it is as linearly polarized outgoing lights L3Don and L3Con having a polarization direction of 90 °.

  As described above, according to the present embodiment, since each electrode and each separation portion of the polarization switching element 2 and the polarization switching element 3 are alternately combined when viewed from the direction in which light passes, one polarization switching is performed. The polarization direction of the linearly polarized light transmitted through the separation portion of the element 2 (or the polarization switching element 3) can be rotated by 90 degrees at the electrode portion of the other polarization switching element 3 (or the polarization switching element 2). Therefore, by switching the polarization direction of the linearly polarized light that passes through the electrode part, the polarization direction of the linearly polarized light that passes through the separated part is also switched, and the light that passes through the separated part between the electrodes without any discrepancy in the polarization direction. The generated crosstalk can be reduced.

  In addition, according to the present embodiment, for example, the incident light to the liquid crystal molecules facing the separation portion is made by aligning the alignment axis direction of the liquid crystal molecules parallel or orthogonal to the polarization direction of the incident light or matching the incident direction of the incident light. Can be transmitted without rotation without changing the polarization direction.

  Further, according to the present embodiment, by setting the orientation axis direction of the region 41 to 135 ° and the orientation axis direction of the region 51 to 45 °, the polarization direction of both the polarization switching element 2 and the polarization switching element 3 is 90 °. A phase difference of λ / 2 can be generated in the liquid crystal layer in which the alignment axis direction of the liquid crystal molecules is rotated by 45 ° with respect to the linearly polarized light.

  Further, according to the present embodiment, the polarization direction can be switched by switching between a state in which a predetermined voltage is applied and a state in which no voltage is applied at each electrode of the polarization switching element 2 and the polarization switching element 3. Can be switched.

  Next, a modification of the polarization switching device 1 shown in FIG. 1 will be described with reference to FIGS. 9 and 10. In FIG. 9, the same reference numerals are used for the same components as those shown in FIG. A polarization switching device 1a, which is a modification of the polarization switching device 1 shown in FIG. 9, includes a polarization switching element 2a and a polarization switching element 3a. The polarization switching element 2a is obtained by changing the electrode 26 on the glass substrate 23 side of the polarization switching element 2 in FIG. 1 to an electrode 40 provided over the entire surface of the glass substrate 23 as shown by shading in FIG. It is. The polarization switching element 3a is obtained by replacing the electrode 36 on the glass substrate 33 side of the polarization switching element 3 in FIG. 1 with an electrode 50 provided over the entire surface of the glass substrate 33 as shown by shading in FIG. It is. Further, the alignment film 47 and the alignment film 49 are alternately formed on the electrode 40. In addition, the alignment film 57 and the alignment film 59 are alternately formed on the electrode 50. Regions 44, 45, 54, and 55 correspond to regions 41, 43, 51, and 53 in FIG. 1, respectively. In addition, the alignment films 47, 49, 57, and 55 are aligned so that the alignment axis directions of the regions 44, 45, 54, and 55 are the same as the alignment axis directions of the regions 41, 43, 51, and 53 shown in FIG. 59 orientation directions are set.

  In the polarization switching device 1a shown in FIG. 9, when a voltage is applied to the liquid crystal layer 21 or the liquid crystal layer 31, a predetermined voltage is applied between the electrode 24 and the electrode 40 or between the electrode 34 and the electrode 50. To do. Further, the polarization direction switching operation related to the incident light L1, the light L2, and the outgoing light L3 is the same as that of the polarization switching device 1 of FIG.

  Next, another embodiment of the polarization switching device according to the present invention will be described with reference to FIGS. The polarization switching device 1b of the present embodiment includes the polarization switching element 2 and the polarization switching element 3 described with reference to FIG. 1 and a newly provided polarization element 4. The polarization switching element 2 and the polarization switching element 3 are the same as those shown in FIG. The polarizing element 4 is a λ / 4 plate that mutually converts linearly polarized light and circularly polarized light using birefringence. In this case, the polarizing element 4 is provided in contact with the surface on the outgoing light side of the glass substrate 33 of the polarization switching element 3. The polarization switching device 1b receives linearly polarized incident light L1, switches the polarization direction to generate linearly polarized outgoing light L3, converts this into circularly polarized light, and emits circularly polarized light L4.

  FIG. 12 shows the output light L3 and the polarization element 4 incident on the polarization element 4 when no voltage is applied between the electrode 24 and the electrode 26 and between the electrode 34 and the electrode 36 in the polarization switching device 1b of FIG. The relationship with the emitted circular knitting light L4 is shown. The outgoing light L3 incident on the polarizing element 4 in FIG. 12 corresponds to the outgoing lights L3Coff and L3Doff described with reference to FIGS. The polarization element 4 has a direction of the optical axis E (for example, a slow axis) of 45 °, and the polarization direction of the linearly polarized outgoing light L3 incident on the optical axis E is 45 ° with respect to the optical axis E. When it has an inclination angle, a phase difference of λ / 4 (that is, 90 °) is generated. In this case, the outgoing lights L3Coff and L3Doff incident on the polarizing element 4 are linearly polarized light whose polarization direction is 0 ° (or 180 °), and thus are light in the polarization direction having an inclination of 45 ° with respect to the optical axis E. Therefore, the linearly polarized outgoing light L3 is converted into circularly polarized light by the polarizing element 4, and the circularly polarized light L4off is emitted from the polarizing element 4.

  On the other hand, FIG. 13 shows the outgoing light L3 incident on the polarizing element 4 when a predetermined voltage is applied between the electrode 24 and the electrode 26 and between the electrode 34 and the electrode 36 in the polarization switching device 1b of FIG. The relationship with the circularly polarized light L4 emitted from the polarizing element 4 is shown. The outgoing light L3 incident on the polarizing element 4 (polarizing element) in FIG. 13 corresponds to the outgoing lights L3Con and L3Don described with reference to FIGS. Also, as described with reference to FIG. 12, the polarization element 4 is configured to polarize the linearly polarized outgoing light L3 incident on the optical axis E with the direction of the optical axis E (for example, the slow axis) being 45 °. When the direction has a tilt angle of 45 ° with respect to the optical axis E, a phase difference of λ / 4 (ie 90 °) is generated. In this case, the outgoing lights L3Con and L3Don entering the polarizing element 4 are linearly polarized light having a polarization direction of 90 °, and therefore have an inclination of 45 ° with respect to the optical axis E. Accordingly, the linearly polarized outgoing light L3 is converted into circularly polarized light by the polarizing element 4, and the circularly polarized light L4on is emitted from the polarizing element 4. The circularly polarized light L4on and the circularly polarized light L4off in FIG. 12 have different polarization component rotation directions.

  According to this embodiment, the incident linearly polarized incident light L1 can be converted into clockwise or counterclockwise circularly polarized light L4.

  Next, another embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is used for the structure same as what was shown in FIG.1, FIG9 and FIG.11. The display system shown in FIG. 14 constitutes a system for displaying a stereoscopic image (or simultaneously displaying two different images) using the polarization switching device 1, the polarization switching device 1a, or the polarization switching device 1b described above. Is. The stereoscopic image display system (image display device) shown in FIG. 14 includes a single projector 100 (output device) and a polarization switching device 1 or 1a that switches the polarization direction of linearly polarized light emitted from the projector 100 (FIG. 14). 14 (a)) or the polarization switching device 1b (in the case of FIG. 14 (b)) and the control device 5 for controlling the polarization switching device 1, 1a or 1b. For example, the projector 100 switches the left-eye image (first image) and the right-eye image (second image) (or two types of images) alternately and emits them in a time-sharing manner. At that time, the projector 100 uses the linearly polarized incident light L1 having a polarization direction of 90 ° to generate the left-eye image light (first emitted light) and the right-eye image light (second emitted light) (or two types). Are emitted at a predetermined cycle.

  Then, the polarization switching device 1, 1a or 1b receives the linearly polarized incident light L1 emitted from the projector 100, and emits or rotates the emitted light L3off obtained by rotating the polarization direction of the incident linearly polarized light by 90 °. Without being emitted as it is as the emitted light L3on, or further converted into circularly polarized light and emitted as circularly polarized light L4off or L4on. Switching of the polarization direction by the polarization switching device 1, 1 a or 1 b is performed by the control device 5 in synchronization with the time division switching time between the left-eye image and the right-eye image in the projector 100. The control device 5 receives a predetermined control signal output from the projector 100 (or an image signal including the same left-eye image and right-eye image as those input to the projector 100), and the polarization switching device 1 based on the input control signal. 1a or 1b is controlled. When the left-eye image or the right-eye image is emitted from the projector 100, the control device 5 uses the polarization switching elements 2 and 3 for each scanning line (or in units of a plurality of scanning lines or all scanning lines) according to the scanning method. ) The voltage applied to the corresponding one or more electrodes 24 and 34 is controlled by switching to a predetermined voltage or 0 (that is, not applied). The image scanning method by the projector 100 may be a surface scanning method or a line scanning method.

As described above, the polarization switching device 1 (polarization switching device) of the present invention includes the polarization switching element 2 (first polarization switching means) and the polarization switching element 3 (second polarization switching means).
The polarization switching element 2 includes a plurality of electrodes 24 and an electrode 26 (first electrode) arranged with a spacing portion 42 (a spacing portion) therebetween. The polarization switching element 2 has a liquid crystal layer 21 (first liquid crystal layer) made of liquid crystal molecules that generate birefringence. In the region 41 (a region to which a voltage is applied using the plurality of first electrodes) in the liquid crystal layer 21, a state in which no voltage is applied to the electrode 24 and the electrode 26 (the first electrode has a predetermined value) In the first voltage application state, the polarization direction of the linearly polarized light incident through the liquid crystal molecules facing the first electrode is rotated by 90 degrees and transmitted. In the region 41 of the liquid crystal layer 21, when the voltage is applied to the electrode 24 and the electrode 26 (the first electrode is in a predetermined second voltage application state), the first The polarization direction of the incident linearly polarized light is transmitted through the liquid crystal molecules facing the electrodes without rotation. Further, in the liquid crystal layer 21, in a region 43 (a region where the voltage is not applied while being opposed to the separation portion between the plurality of first electrodes), the liquid crystal molecules opposed to the separation portion between the plurality of first electrodes are arranged. The polarization direction of the incident linearly polarized light is transmitted without rotation.

  In addition, the polarization switching element 3 is a plurality of electrodes arranged at a distance from each other, and is disposed at a position facing the separation portion of the plurality of first electrodes and facing the first electrode. Are a plurality of electrodes 34 and electrodes 36 (second electrodes). The polarization switching element 3 includes a liquid crystal layer 31 (second liquid crystal layer) made of liquid crystal molecules that generate birefringence. In the liquid crystal layer 31, in a region 51 (a region where a voltage is applied using the plurality of second electrodes), a state in which no voltage is applied to the electrode 34 and the electrode 36 (the second electrode is a predetermined voltage). In the third voltage application state, the polarization direction of the linearly polarized light incident from the first polarization switching element is transmitted through the liquid crystal molecules facing the second electrode after being rotated by 90 degrees. Further, in the region 51 of the liquid crystal layer 31, when the voltage is applied to the electrode 34 and the electrode 36 (the second electrode is in a predetermined fourth voltage application state), the second The polarization direction of linearly polarized light incident from the first polarization switching element is transmitted through the liquid crystal molecules facing the electrode without rotation. Further, in the liquid crystal layer 31, in a region 53 (a region where the voltage is not applied while being opposed to the separated portion between the plurality of second electrodes), liquid crystal molecules opposed to the separated portion between the plurality of second electrodes are arranged. The polarization direction of linearly polarized light incident from the first polarization switching element is transmitted without rotation.

  According to the present embodiment, the viewer wears glasses equipped with analyzers having different polarization directions on the left and right sides, and observes the light reflected by the screen, thereby reducing crosstalk between different images. Different images can be viewed separately. Further, according to the present embodiment, when projecting a stereoscopic image, it is possible to reduce the crosstalk between the left-eye image and the right-eye image and to appreciate the stereoscopic image.

  The embodiment of the present invention is not limited to the above, and for example, the number of electrodes can be changed, the polarization switching elements 2 and 3 can be provided in contact with each other, or the alignment axis can be provided. It is possible to appropriately change the direction.

DESCRIPTION OF SYMBOLS 1, 1b Polarization switching apparatus 2, 3 Polarization switching element 4 Polarizing element 21, 31 Liquid crystal layer 22, 23, 32, 33 Glass substrate 24, 26, 34, 36 Electrode 25, 27, 28, 29 Alignment film 40, 50 Electrode 41, 51 Areas 42, 52 facing the electrodes Spacing parts 43, 53 Areas facing the spacing parts

Claims (7)

A plurality of first electrodes arranged with a space therebetween,
In a region composed of liquid crystal molecules that generate birefringence and to which a voltage is applied using the plurality of first electrodes, the first electrode is applied when the first electrode is in a predetermined first voltage application state. When the polarization direction of linearly polarized light incident through the liquid crystal molecules facing the electrode is rotated by 90 degrees and transmitted, and the first electrode is in a predetermined second voltage application state, the first polarization is applied. In the region where the polarization direction of the incident linearly polarized light is transmitted without rotation through the liquid crystal molecules facing the electrodes and is opposed to the separation portion between the plurality of first electrodes and no voltage is applied, First polarization switching means comprising: a first liquid crystal layer that non-rotatably transmits the polarization direction of the incident linearly polarized light via a liquid crystal molecule facing a separation portion between the one electrode;
A plurality of electrodes arranged at a distance from each other, the electrodes being arranged at positions facing the spacing portions of the plurality of first electrodes, and having positions facing the first electrodes as spacing portions. Two electrodes;
In a region composed of liquid crystal molecules that generate birefringence and to which a voltage is applied using the plurality of second electrodes, the second electrode is applied when the second electrode enters a predetermined third voltage application state. The polarization direction of the linearly polarized light incident from the first polarization switching element through the liquid crystal molecules facing the electrode is rotated by 90 degrees and transmitted, and the second electrode is in a predetermined fourth voltage application state. In this case, the polarization direction of the linearly polarized light incident from the first polarization switching element is transmitted through the liquid crystal molecules facing the second electrode without rotation, and is transmitted to the separation portion between the plurality of second electrodes. In a region where no voltage is applied, the polarization direction of the linearly polarized light incident from the first polarization switching element is transmitted without rotation through the liquid crystal molecules facing the spacing between the plurality of second electrodes. A second polarization switch having two liquid crystal layers And a polarization switching device. The polarization direction of linearly polarized light incident on the first polarization switching element is opposite to the alignment axis direction of the liquid crystal molecules facing the separation portion between the first electrodes and the separation portion between the second electrodes. The polarization switching device according to claim 1, wherein the polarization switching device is parallel or orthogonal to the alignment axis direction of the liquid crystal molecules. The polarization direction of the linearly polarized light incident on the first polarization switching element is the alignment axis direction of the liquid crystal molecules facing the first electrode and the third voltage application state in the first voltage application state. The polarization switching device according to claim 1, wherein the polarization switching device is inclined by 45 degrees with respect to the alignment axis direction of the liquid crystal molecules facing the second electrode. The first voltage application state is a state in which no voltage is applied to the first electrode;
The second voltage application state is a state in which a predetermined voltage is applied to the first electrode;
The third voltage application state is a state in which no voltage is applied to the second electrode;
The polarization switching device according to any one of claims 1 to 3, wherein the fourth voltage application state is a state in which a predetermined voltage is applied to the second electrode. The polarization switching device according to any one of claims 1 to 4, further comprising a polarization element that converts linearly polarized light emitted from the second polarization switching element into circularly polarized light. An emission device that emits a first emission light representing a first image and a second emission light representing a second image different from the first image at a predetermined period in a time-sharing manner;
The polarization switching device according to any one of claims 1 to 5, wherein outgoing light of the outgoing device is incident as linearly polarized light,
When the emitting device emits the first outgoing light, the first polarization switching device is in the first voltage application state, and the second polarization switching device is in the second voltage application state. And
When the emitting device emits the second outgoing light, the first polarization switching device is in the third voltage application state, and the second polarization switching device is in the fourth voltage application state. An image display device characterized by that. The first image is a left-eye image for stereoscopic viewing;
The image display apparatus according to claim 6, wherein the second image is a right-eye image for stereoscopic viewing.

Images