JP2005070353A - Image display device - Google Patents

Abstract

In an image display device provided with a parallax barrier, a decrease in resolution is prevented without increasing the number of pixels of a display element, and a decrease in display brightness is suppressed.
An image display apparatus includes a display element 109, a shift element 106, and a parallax barrier 105 in this order from an observer side. The display element 109 includes a first pixel group for displaying the first image and a second pixel group for displaying the second image. The parallax barrier 105 includes at least a plurality of light transmission regions 105a that transmit polarized light in a specific polarization state and a plurality of light shielding regions 105b that block light polarized in a specific polarization state, and each of the plurality of light transmission regions 105a includes The plurality of first pixels 120R belonging to the first pixel group are arranged corresponding to each. The shift element 106 can shift the principal ray of light transmitted through each of the plurality of light transmission regions 105a of the parallax barrier 105 so as to correspond to each of the plurality of second pixels 120L belonging to the second pixel group. .
[Selection] Figure 1

Description

  The present invention relates to an image display device provided with a parallax barrier.

  One of the typical methods for displaying a stereoscopic image using an image display device that displays a two-dimensional image is a parallax barrier method. With the parallax barrier method, a stereoscopic view is realized by observing the display surface through this barrier by providing a band (barrier) in which light transmitting parts and light shielding parts are alternately arranged on the front or rear of the image display device. It is a method to make it.

  Patent Document 1 discloses a stereoscopic image display device including a parallax barrier on the viewer side of a liquid crystal display element (Liquid Crystal Display: hereinafter referred to as “LCD”) as shown in FIG.

  The image display apparatus of FIG. 6 includes a parallax barrier 6, an LCD 1, and a backlight 2 from the observer side. The LCD 1 has a configuration in which a liquid crystal layer 5 is sandwiched between a pair of glass substrates 3 and 4 each having a driving electrode, wiring, a thin film transistor (TFT), a color filter, and the like. Polarizing plates (not shown) are respectively disposed on the light incident surface and the light emitting surface of the LCD 1. The LCD 1 has a plurality of pixels and performs display by changing the polarization state of light by applying a voltage to the liquid crystal layer 5 of each pixel.

  In FIG. 6, the LCD 1 displays a left-eye image on a pixel with a “left” character and a right-eye image on a pixel with a “right” character. Since the parallax barrier 6 blocks the light from the LCD 1 at the light shielding portion, the image from the LCD 1 is observed by the observer only through the light transmitting portion of the parallax barrier 6. At this time, by appropriately setting the pattern and arrangement of the parallax barrier 6, the observer's right eye can display only the image displayed by the “right” pixel, and the left eye can display only the image displayed by the “left” pixel. Can see. Since the images displayed by the “left” pixel and the “right” pixel are given parallax, the observer can perform stereoscopic viewing.

  In FIG. 6, for convenience of explanation, the thickness of the liquid crystal layer 5 is emphasized. However, the actual thickness of the liquid crystal layer 5 is on the order of several μm, which is very small compared to the thickness of the glass substrates 3 and 4 on the order of mm. Small. Further, since the parallax barrier 6 is made of a metal mask or the like provided with a low reflection film, the actual thickness of the parallax barrier 6 is also smaller than the illustrated thickness.

  Patent Document 2 discloses an image display device capable of switching between stereoscopic display and two-dimensional display by optically controlling the presence or absence of a parallax barrier. The parallax barrier in this image display device has a configuration in which a striped half-wave plate, a liquid crystal cell that converts linearly polarized light into circularly polarized light, and a polarizing plate are combined.

  As shown in FIG. 7, the image display device of Patent Document 2 includes a parallax barrier 11, a polarizing plate 12, a liquid crystal display panel 13, and a polarizing plate 14 in this order from the observer side. The parallax barrier 11 includes a polarizing plate 15, a liquid crystal cell 16, and a phase difference plate array (stripe half phase difference plate) 17 in this order.

  When the linearly polarized light A from the liquid crystal display panel 13 enters the phase difference plate array 17, the polarization direction is rotated by 90 °, converted into linearly polarized light B orthogonal to the linearly polarized light A, and emitted. On the other hand, the light that has passed through the opening of the phase difference plate array 17 in the linearly polarized light A is output as the linearly polarized light A because the polarization state is maintained.

  The two linearly polarized lights A and B emitted from the phase difference plate array 17 subsequently enter the liquid crystal cell 16. When a voltage is applied to the liquid crystal cell 16 (ON state), as shown in Table 1, the linearly polarized light A and B incident on the liquid crystal cell 16 are emitted in their respective polarization states. Thereafter, since the polarization direction of one of the linearly polarized light A and the linearly polarized light B coincides with the transmission axis of the polarizing plate 15, the light is emitted from the polarizing plate 15, and the other linearly polarized light is cut by the polarizing plate 15. Thus, in this image display device, the retardation film array 17 itself can function as a parallax barrier, so that a stereoscopic image can be displayed.

  On the other hand, when no voltage is applied to the liquid crystal cell 16 (OFF state), the linearly polarized light A and B incident on the liquid crystal cell 16 are converted into circularly polarized light a and b around each other and emitted. Thereafter, only the polarization component that coincides with the transmission axis of the respective polarizing plates 15 of the circularly polarized light a and b is emitted from the polarizing plate 15. That is, both of these circularly polarized light a and b partially pass through the polarizing plate 15. In this case, since the stripe-shaped 1/2 phase difference plate 17 does not function as a parallax barrier, a two-dimensional image is displayed.

  Further, Patent Document 3 also discloses a display device capable of switching between stereoscopic display and two-dimensional display. The apparatus of Patent Document 3 has a configuration in which a parallax barrier, a shift element, and a display element are arranged in this order from the observer side. The parallax barrier is configured by alternately arranging two types of stripe-shaped polarizing plates.

  In the apparatus of Patent Document 3, the function of the parallax barrier can be switched by inverting the light transmitting portion and the light shielding portion of the parallax barrier using a shift element. By synchronizing the switching of the function of the parallax barrier and the switching of the display of each pixel of the display element, the observer can observe a high-resolution stereoscopic image.

  The parallax barrier method is a simple stereoscopic image display method, but a conventional stereoscopic image display device using the parallax barrier method has the following problems.

  In the parallax barrier type stereoscopic image display device of Patent Document 1, a half of the total number of pixels of the display element can be seen only by the left eye and the other half can be seen only by the right eye. The brightness and resolution of the display are halved compared to a display device without it.

  Patent Document 1 describes that a two-dimensional image can be displayed by removing the polarizing plate, but the resolution is halved even when the two-dimensional image is displayed.

  In order to realize display with a predetermined resolution using the apparatus of Patent Document 1, it is necessary to use a liquid crystal display element having the number of pixels double the desired resolution in the horizontal direction. For example, if an attempt is made to construct a display device capable of displaying a three-dimensional image while securing XGA (vertical 768 dots × horizontal 1024 dots (× RGB)) when displaying a two-dimensional image as a computer display, A liquid crystal display element with horizontal 2048 dots (× RGB) must be prepared. Therefore, since the XGA liquid crystal display element cannot be used as it is in a stereoscopic image display device, it is necessary to newly manufacture a high-resolution liquid crystal display element for stereoscopic image display.

  However, since the manufacturing yield of liquid crystal display elements generally decreases as the number of pixels increases, if a high-resolution liquid crystal display element is purposely manufactured, the price of an image display device including the liquid crystal display element increases. For this reason, it is desirable to realize a stereoscopic image display apparatus that uses the current product and that does not lower the resolution when displaying at least a two-dimensional image.

  In order to display a two-dimensional image without reducing the brightness and resolution in the parallax barrier type stereoscopic image display device, there is a method of removing the parallax barrier during the two-dimensional image display. However, in this method, in order to display a stereoscopic image again after displaying a two-dimensional image, it is necessary to install the parallax barrier so as to be accurately in a predetermined state, which is substantially difficult. In other words, the parallax barrier is slightly rotated or displaced with respect to the liquid crystal display element, and interference occurs between the parallax barrier pattern and the pixel array of the liquid crystal display element, thereby forming moire fringes. As a result, stereoscopic vision is hindered. Although it is possible to manufacture a mechanism for accurate alignment so that moiré fringes do not occur, this requires a design and processing technology that requires higher accuracy than the pixel pitch, which increases costs. In addition, the display device itself is increased in size.

  Next, in the image display device that optically controls the presence or absence of the parallax barrier of Patent Document 2, when displaying a two-dimensional image without functioning the parallax barrier, all pixels (pixels for the right eye and the left eye) are displayed. ) Is visible with both eyes. Therefore, a predetermined resolution can be maintained even when a normal two-dimensional image display element is used. However, when the circularly polarized light a and b are emitted as linearly polarized light to the viewer side by the polarizing plate 15, more than half of the circularly polarized light a and b is cut, so that the same as at the time of stereoscopic image display. The brightness of the display decreases. Furthermore, in this image display device, the resolution and brightness are reduced when a stereoscopic image is displayed.

In the display device of Patent Document 3, it is possible to alternately observe images from half of the pixels in a time-division manner even when displaying a two-dimensional image or displaying a stereoscopic image, so that the resolution can be maintained. . However, since the light emitted from the display element is observed through the parallax barrier, the brightness of the image is halved. Furthermore, in this display element, it is necessary to dispose stripe-shaped polarizing elements whose polarization axes are orthogonal to each other at a pitch of about twice the pixel pitch, and it is difficult to manufacture such a polarizing element, which is very expensive. .
Japanese Patent Laid-Open No. 10-268230 JP-A-10-123461 Japanese Patent Laid-Open No. 9-15532

  The problem to be solved by the present invention is to prevent a decrease in resolution and suppress a decrease in display brightness without increasing the number of pixels of a display element in an image display device having a parallax barrier. is there.

  The image display device of the present invention includes a display element, a shift element, and a parallax barrier in this order from the observer side. The display element includes a first pixel group for displaying a first image, a first pixel group, A second pixel group for displaying two images, wherein the parallax barrier includes at least a plurality of light transmission regions that transmit polarized light in a specific polarization state and a plurality of light that blocks light polarized in the specific polarization state. Each of the plurality of light transmission regions is arranged corresponding to each of the plurality of first pixels belonging to the first pixel group, and the shift element is formed of the parallax barrier. The principal ray of the light transmitted through each of the plurality of light transmission regions can be shifted so as to correspond to each of the plurality of second pixels belonging to the second pixel group.

  In a preferred embodiment, the shift element further includes a polarization conversion element capable of converting a polarization state of incident light on a side opposite to an observer of the shift element, and the shift element corresponds to a polarization state of the principal ray. To shift the principal ray.

  The polarization conversion element changes the polarization state of the first polarization emitted from the polarization element and the polarization state of the first polarization emitted from the polarization element, and changes the polarization state of the second polarization different from the polarization state of the first polarization. It is preferable to have a polarization control element that can emit light.

  The first polarized light emitted from the polarizing element may be linearly polarized light, and the second polarized light may be linearly polarized light whose polarization direction is approximately 45 ° with respect to the first polarized light. The first polarized light emitted from the polarizing element may be linearly polarized light, and the second polarized light may be circularly polarized light. Furthermore, the first polarized light emitted from the polarizing element may be linearly polarized light, and the second polarized light may be linearly polarized light whose polarization direction is orthogonal to the first polarized light.

  In a preferred embodiment, the polarization control element includes at least one liquid crystal cell, and the at least one liquid crystal cell has a first state that maintains a polarization state of incident polarized light according to an applied voltage, and an incident state. Switching between the second state for changing the polarization state of the polarized light is possible.

  In a preferred embodiment, the polarization control element includes at least two liquid crystal cells, and the at least two liquid crystal cells have a first state that maintains a polarization state of incident polarized light according to an applied voltage, and an incident state. The first polarized light that is switched between the second state that changes the polarization state of the polarized light and that rotates the polarization direction of the incident linearly polarized light in the second state by approximately 45 °. The polarization control element emits the second polarized light orthogonal to the first polarized light when both of the two liquid crystal cells are in the second state.

  In a preferred embodiment, the polarization control element includes at least two liquid crystal cells, and the at least two liquid crystal cells have a first state that maintains a polarization state of incident polarized light according to an applied voltage, and an incident state. Switching between the second state for changing the polarization state of polarized light and functioning as a quarter-wave plate in the second state, the first polarized light emitted from the polarizing element is linearly polarized light The polarization control element emits the second polarized light orthogonal to the first polarized light when both of the two liquid crystal cells are in the second state.

  The light emitted from the shift element passes through the shift element without being shifted, and is shifted by the shift element and the plurality of first light corresponding to each of the first pixel groups, A plurality of second lights corresponding to each of the pixel groups can be included.

  An optical path correction element that makes the optical path lengths of the plurality of first lights and the optical path lengths of the plurality of second lights the same may be further provided between the shift element and the display element. The optical path correction element is preferably provided on an optical path of the plurality of second lights.

  In a preferred embodiment, the shift element includes a polarization beam splitter array, and the polarization beam splitter array includes a plurality of polarization separation surfaces each transmitting or reflecting the principal ray according to a polarization state of the principal ray. have. The polarization separation surface may have a function of transmitting a P polarization component with respect to the polarization separation surface and reflecting an S polarization component with respect to the polarization separation surface.

  A polarization correction element is further provided between the shift element and the display element, and the polarization correction element includes the plurality of first lights so that the plurality of first lights and the plurality of second lights are in the same polarization state. The polarization state of the light and / or the plurality of second lights can be corrected. The polarization correction element may include a half-wave plate, and may be provided in the optical path of the plurality of first lights and / or the optical path of the plurality of second lights.

  In a preferred embodiment, the microlens array further includes a microlens array on a side opposite to the observer of the parallax barrier, and the microlens array corresponds to each of the plurality of light transmission regions of the parallax barrier. It has a plurality of microlenses. The microlens array may be a lenticular lens.

  In a preferred embodiment, the display element alternately displays the first image and the second image.

  The first image may include one of a right-eye image and a left-eye image, and the second image may include the other of them.

  According to the present invention, for example, a stereoscopic image display and a two-dimensional image display can be switched by optically shifting the position of the light shielding region of the parallax barrier using the shift element. When displaying stereoscopic images, the left-eye pixels and right-eye pixels are alternately displayed in time division in synchronization with the switching of the parallax barrier position, so that a good stereoscopic image can be displayed without reducing the resolution. Can be displayed. Similarly, even when displaying a two-dimensional image, it is possible to prevent a reduction in resolution by performing time-division display.

  Furthermore, the light utilization efficiency can be improved by placing a microlens on the light incident side of the parallax barrier and condensing the light in the light transmission area (opening slit) of the parallax barrier, thus improving the display brightness. it can.

  Hereinafter, the configuration of an image display device according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 8A, the image display apparatus according to this embodiment includes a display element 109, a shift element 106, and a parallax barrier 105 in this order from the observer side. Therefore, light emitted from a light source or the like first enters the parallax barrier 105 and reaches the display element 109 via the shift element 106.

  The display element 109 includes a first pixel group that displays a first image and a second pixel group that displays a second image. The first pixel group includes a plurality of first pixels 120R, and the second pixel group includes a plurality of second pixels 120L. The first and second images are, for example, a right eye image and a left eye image.

  The parallax barrier 105 has a configuration in which a plurality of light transmission regions 105a that transmit at least polarized light in a specific polarization state and a plurality of light shielding regions 105b that shield light in a specific polarization state are alternately arranged. ing. The parallax barrier 105 is manufactured using, for example, a metal mask provided with a low reflection film, and may be a parallax barrier that transmits or blocks all incident light, or 2 having transmission axes orthogonal to each other. It may be a parallax barrier having a configuration in which different types of stripe-shaped polarizing plates are alternately arranged and transmitting or blocking specific linearly polarized light. Further, it only needs to function as a parallax barrier and does not need to be a single component. For example, a half-wave plate, a liquid crystal cell, and a polarizing plate may be combined. Each of the plurality of light transmission regions 105a of the parallax barrier 105 is disposed corresponding to each of the plurality of first pixels 120R belonging to the first pixel group.

  As the parallax barrier 105, it is preferable to use a parallax barrier using a light-shielding film such as a metal mask or a stripe retardation plate. Since these can be easily and inexpensively produced using a photolithographic method or a printing method, for example, it is advantageous compared to the case of using a stripe-shaped polarizing element having orthogonal polarization axes used in the display device of Patent Document 3. is there.

  As shown in FIG. 8C, the shift element 106 corresponds to the principal ray of light transmitted through each light transmission region 105a of the parallax barrier 105 to each of the plurality of second pixels 105b belonging to the second pixel group. Can be shifted. Accordingly, the light shifted by the shift element 106 enters the second pixel 120L of the display element 109 (FIG. 8C), and the light that has passed without being shifted enters the first pixel 120R of the display element 109 ( FIG. 8 (a)).

  The effect obtained by arranging the shift element 106 will be described in more detail with reference to FIGS. As shown in FIG. 8A, the light that has passed through the light transmission region 105 a of the parallax barrier 105 is emitted as it is before being shifted by the shift element 106. On the other hand, when the shift element 106 is caused to function, the light transmitted through the parallax barrier 105 is shifted by the shift element 106 as shown in FIG. As a result of such a shift, the same effect as when the position of the light shielding region of the parallax barrier 105 itself is shifted is obtained. FIG. 8B is substantially the same view as FIG. 8C, but shows the parallax barrier 105 in dotted lines at the optically shifted position. Thus, in this specification, the apparent position of the parallax barrier 105 from the observer is illustrated by a dotted line. Since the parallax barrier is optically shifted and not actually shifted, it is not necessary to align the parallax barrier 105 with high accuracy each time the shift is performed. In this way, if the apparent position of the parallax barrier 105 is shifted in a time division manner, the first pixel and the second pixel can be displayed alternately, so that a decrease in resolution can be prevented.

  As shown in FIG. 9B, the shift element 106 preferably functions so that a part of the light C transmitted through the parallax barrier 105 is shifted (C2) and the rest is not shifted (C1). As a result, the same effect as in the case where the parallax barrier 105 is not substantially disposed (the parallax barrier 105 is removed) can be obtained. FIG. 9A is substantially the same view as FIG. 9B, but shows the parallax barrier 105 and its light shielding area by dotted lines. In this specification, the parallax barrier 105 which is not substantially functioning is illustrated by a dotted line as shown in FIG. As described above, when the shift element 106 functions as shown in FIG. 9, the first pixel and the second pixel can be displayed simultaneously.

  In the image display device of the present embodiment, the first image displayed by the first pixel and the second image displayed by the second pixel are the right (left) eye image and the left (right) eye image. By shifting the apparent position of the parallax barrier 105 in a time division manner, a stereoscopic image can be displayed without reducing the resolution. Further, when the shift element 106 functions as shown in FIG. 9, it is possible to switch to the planar image display.

  The shift element 106 is preferably capable of shifting the principal ray according to the polarization state of the principal ray of the light that has passed through the parallax barrier, such as a polarization beam splitter array. Thereby, the apparent position of the parallax barrier can be efficiently shifted by appropriately controlling the polarization state of the light incident on the shift element. In addition, when a liquid crystal display element is used as the display element, the light incident on the liquid crystal display element from the shift element is polarized light in advance, so there is no need to dispose a polarizing plate on the light incident side of the liquid crystal display element. Therefore, the display element configuration can be simplified. Even when the polarizing plate is disposed on the light incident side of the liquid crystal display element, there is almost no loss of light due to the polarizing plate, and the incident light to the liquid crystal display element can be used efficiently.

  When using a shift element that shifts light according to the polarization state as described above, it is preferable to provide a polarization conversion element in order to control the polarization state of light from a light source or the like. The polarization conversion element may be arranged on the side opposite to the observer of the shift element, may be arranged on the observer side of the parallax barrier, or may be arranged on the opposite side thereof. By controlling the polarization state of the light incident on the shift element using the polarization conversion element, the optical path of the light emitted from the shift element can be controlled.

  The polarization conversion element is different from the polarization state of the first polarization by changing the polarization state of the polarization element that changes the light from the light source into polarization and the polarized light emitted from the polarization element (referred to as “first polarization”). A polarization control element capable of emitting the second polarized light having a polarization state may be provided. The first polarized light emitted from the polarizing element is, for example, linearly polarized light. The second polarized light emitted from the polarization control element may be linearly polarized light whose polarization direction is orthogonal to the first polarized light, or may be linearly polarized light whose polarization direction is approximately 45 °. Alternatively, the second polarized light may be circularly polarized light. The polarizing element is, for example, a polarizing plate that transmits only a specific linearly polarized light component.

  It is preferable that the polarization conversion element can switch the polarization state of the light emitted from the polarization conversion element. Since the optical path of the light from the shift element is switched according to the polarization state, the image from the first pixel and the image from the second pixel can be displayed alternately, or the stereoscopic image display and the planar image display can be switched. An image display device can be configured.

  The polarization control element preferably includes at least one liquid crystal cell. The liquid crystal cell design is advantageous because the polarization state of the second polarized light can be freely selected. The liquid crystal cell can be switched between a first state that maintains the polarization state of incident polarized light (first polarization) and a second state that changes the polarization state of incident polarized light according to the voltage applied to the liquid crystal cell. is there. That is, the ON / OFF control of the voltage applied to the liquid crystal cell can selectively maintain or change the polarization state of the first polarized light.

  Hereinafter, the function of the polarization control element in the present embodiment will be described with reference to the drawings.

  For example, the polarization control element emits the first polarized light D (the applied voltage is ON) and the second polarized light E that forms an angle of about 45 ° with the first polarized light according to the applied voltage. A liquid crystal cell 113 that can switch between two states (applied voltage is OFF) is provided. When the liquid crystal cell 113 is in the first state, as shown in FIG. 10A, the light D that has passed through the parallax barrier 105 and the shift element 106 passes through the first pixel that displays the first image of the display element. For example, it reaches the right eye.

  On the other hand, when the liquid crystal cell is in the second state, the component E1 of the specific linearly polarized light D is not shifted among the principal rays E that have passed through the light transmission region of the parallax barrier 105, as shown in FIG. Only the linearly polarized light component E 2 that passes through the shift element 106 and is orthogonal to the linearly polarized light D is shifted by the shift element 106. As a result, since light is incident on all the pixels (first pixel and second pixel) of the display element, a display similar to that of a display device having a configuration without the parallax barrier 105 can be obtained. Therefore, for example, the state shown in FIG. 10A for displaying a stereoscopic image and the state shown in FIG. 10B for displaying a secondary image can be arbitrarily switched.

  Instead, the polarization control element of the present embodiment has a first state in which the first polarized light D is emitted (applied voltage is ON) and a second state in which the circularly polarized light F is emitted (applied voltage is OFF) according to the applied voltage. And a liquid crystal cell 113 that can be switched between. When the liquid crystal cell 113 is in the first state, as shown in FIG. 13A, the light D that has passed through the parallax barrier 105 and the shift element 106 passes through the first pixel that displays the first image of the display element. For example, it reaches the right eye. On the other hand, when the liquid crystal cell 113 is in the second state, the component F1 of the specific linearly polarized light D among the principal rays F that have passed through the light transmission region of the parallax barrier 105 is shifted, as shown in FIG. Without passing through the shift element, only the linearly polarized light component F2 orthogonal to the linearly polarized light D is shifted by the shift element. As a result, light is incident on all the pixels (first pixel and second pixel) of the display element. Therefore, for example, the state shown in FIG. 13A for displaying a stereoscopic image and the state shown in FIG. 13B for displaying a secondary image can be arbitrarily switched.

  Alternatively, the polarization control element in the present embodiment outputs the first state (FIG. 11A) that emits the first polarized light D and the second polarized light G that is orthogonal to the first polarized light according to the applied voltage. You may have the liquid crystal cell 113 which can switch between 2 states (FIG.11 (b)). When the liquid crystal cell 113 is in the first state, as shown in FIG. 11A, the light D that has passed through the parallax barrier 105 and the shift element 106 passes through the first pixel that displays the first image of the display element. For example, it reaches the right eye. On the other hand, when the liquid crystal cell 113 is in the second state, the principal ray G that has passed through the light transmission region of the parallax barrier 105 is shifted by the shift element 106 as shown in FIG. From the observer side, it seems that the position of the parallax barrier is shifted as shown in FIG. The shifted light G passes through the second pixel that displays the second image of the display element and reaches, for example, the left eye. Thus, the apparent position of the parallax barrier can be shifted by arbitrarily switching the states of FIG. 11A and FIG. 11B. In this device, ON / OFF switching of the voltage applied to the liquid crystal cell is performed at high speed (for example, 120 Hz), and the left-eye image and the right-eye image displayed on the display element are sequentially switched in synchronization with this switching. Display sequentially, it is possible to display a stereoscopic image without reducing the resolution. That is, the observer can observe the stereoscopic image while visually recognizing all the images.

  The polarization control element may include two or more liquid crystal cells as shown below.

  For example, as shown in FIG. 12, two liquid crystal cells that rotate the polarization direction of incident linearly polarized light by approximately 45 ° when the applied voltage is OFF (second state) may be provided. When linearly polarized light (first polarized light) D is incident on the polarization control element, when both of the two liquid crystal cells 103 and 104 are set to the first state, the polarization state of the first polarization D is maintained, and the first polarized light from the polarization control element is maintained. D is emitted (FIG. 12A). Further, when the two liquid crystal cells 103 and 104 of the polarization control element are both in the second state, the polarization control element emits the second polarization G orthogonal to the first polarization D (FIG. 12B). Furthermore, when only one of the liquid crystal cells is in the second state, the second polarized light F that forms an angle of approximately 45 ° with the first polarized light is emitted (FIG. 12C). According to such a configuration, when the voltages of the two liquid crystal cells 103 and 104 are both turned off or on, the parallax barrier 105 functions, so that a stereoscopic image can be simply displayed. Further, by switching ON / OFF of the two liquid crystal cells 103 and 104 at high speed (for example, 120 Hz), the state of FIG. 12A and the state of FIG. 12B are switched at high speed. As described above, the image display apparatus according to the present embodiment can display a stereoscopic image without reducing the resolution. Further, as shown in FIG. 12C, if the voltage of only one of the liquid crystal cells 104 is turned on (second state), as described with reference to FIG. Can be displayed.

  Or as shown in FIG. 14, you may have two liquid crystal cells which function as a quarter wavelength plate in a 2nd state (for example, when an applied voltage is OFF). Each of these liquid crystal cells 103 and 104 converts incident linearly polarized light into circularly polarized light. When linearly polarized light (first polarized light) D is incident on the polarization control element, when both the two liquid crystal cells 103 and 104 are set to the first state (ON), the polarization state of the first polarization D is maintained, and the polarization control element The first polarized light D is emitted (FIG. 14A). Further, when the two liquid crystal cells 103 and 104 of the polarization control element are both in the second state (OFF), the polarization control element emits the second polarization G orthogonal to the first polarization D (FIG. 14B). ). Furthermore, when only one of the liquid crystal cells 104 is set to the second state, circularly polarized light F is emitted (FIG. 14C). According to such a configuration, when the voltages of the two liquid crystal cells 103 and 104 are turned off or on, the parallax barrier 105 functions, so that a stereoscopic image can be simply displayed. Further, by switching the applied voltages of the two liquid crystal cells 103 and 104 at high speed (for example, 120 Hz), the state of FIG. 14A and the state of FIG. 14B are switched at high speed. As described above, the image display apparatus of the present embodiment can display a stereoscopic image without reducing the resolution. Furthermore, as shown in FIG. 14C, when only one of the liquid crystal cells 104 is turned on, a two-dimensional image can be displayed as described with reference to FIG. 9B.

  As described above, the light that has passed through the parallax barrier passes through the shift element without being shifted, and then passes through each of the first pixels that display the first image, for example, the light that reaches the right eye (the first eye). Light) and light (second light) that is shifted by the shift element and passes through each of the second pixels that display the second image and reaches the left eye, for example. At this time, an optical path correction element can be provided between the shift element and the display element in order to make the optical path length of the first light the same as the optical path length of the second light. By providing the optical path correction element, the optical distance between the parallax barrier and the display element in each of the first light and the second light becomes substantially equal to each other, so that a good stereoscopic image can be displayed.

The effect of the optical path correction element will be described in more detail with reference to FIG. If the distance from the parallax barrier 105 to the image display surface of the image display element 109 is d, the observation distance is L, the opening (light transmission region) pitch of the parallax barrier is p, and the distance between the eyes of the observer is E,
L = 2 × d × E / p (1)
The relationship becomes true. From equation (1), it can be seen that as the distance d changes, the observation distance L changes accordingly. Therefore, by arranging the optical path correction elements so that the distances d in the first light and the second light are substantially equal, the optimum observation distances of the first light and the second light by the left and right eyes become substantially equal. Can observe a better image.

  The optical path correction element is preferably arranged on the optical path of the second light. Since the second light is shifted by the shift element, the distance d is longer than the first light that has passed through the shift element as it is. The distance that the light passes varies depending on the refractive index of the medium. That is, if light travels through a medium having a refractive index n by a distance A, the air-converted distance of the optical path length is A / n, which is shortened by the refractive index. Therefore, the optical path length can be efficiently corrected by arranging the optical path correction element using the refractive index in the optical path of the second light having a long optical path length.

  As the shift element, a polarization beam splitter array having a plurality of polarization separation surfaces (hereinafter sometimes referred to as “PBS array”) can be used. The polarization separation surface of the PBS array is arranged to correspond to the light transmission region of the parallax barrier 1: 1. Each polarization separation surface transmits or reflects the principal ray that has passed through the corresponding light transmission region, depending on its polarization state. Thereby, the optical path of the principal ray can be efficiently separated, and a good image can be obtained.

  FIG. 16 shows a specific configuration example of the polarization beam splitter array. In FIG. 16, the polarization separation surfaces 112 are arranged at a pitch that is ½ of the light transmission region of the parallax barrier 105. For example, the polarization separation surface 112 has a function of transmitting a P-polarized component with respect to the polarization separation surface 112 and reflecting an S-polarization component with respect to the polarization separation surface 112.

  When P-polarized light, S-polarized light, 45 ° linearly polarized light, circularly polarized light, or the like whose polarization state is controlled by the polarization conversion element is incident on the polarization beam splitter array 106, the P-polarized component of the incident light is converted into each polarization separation surface. The light passes through 112 and is emitted to the viewer side. On the other hand, when the S polarization component of the incident light is reflected by one polarization separation surface 112 -A, it is reflected again by the adjacent polarization separation surface 112 -B, and as a result, corresponds to the light shielding region of the parallax barrier 105. The light is emitted from the position to the viewer side. That is, the S-polarized component of the incident light is shifted from the P-polarized component by approximately the same distance as the pixel pitch of the display element. In this manner, when the PBS array 106 is used, light that has passed through the 105 light transmission region of the parallax barrier can be accurately and efficiently shifted according to the arrangement pitch of the polarization separation surfaces 112.

  As shown in FIG. 16, since the optical path of the S-polarized component is bent once by the shift element (PBS array) 106, the optical path length of the S-polarized component becomes longer than the optical path length component of the P-polarized light. Therefore, when the above-described optical path correction element 111 is arranged on the optical path through which the S-polarized component passes, the observation distances of the P-polarized component and the S-polarized component are substantially the same, and a good image is obtained.

  In addition, it is preferable to arrange the polarization correction element on the optical path of the P-polarized component and / or the S-polarized component emitted from the shift element. For example, a polarization correction element that converts P-polarized light to S-polarized light is disposed on the optical path of the P-polarized light component. When a liquid crystal display element that displays pixels by controlling the polarization of light is used as the display element, the polarization direction of light to be incident on the liquid crystal display element is determined in advance. For this reason, a polarization correction element for correcting the polarization direction is provided on the optical path of the first light incident on the first pixel and / or the second light incident on the second pixel, and the light incident on the display element (first light) Further, by making the polarization direction of the second light) constant, a good image can be obtained.

  As the polarization correction element, for example, a half-wave plate can be used. If the half-wave plate is used, the polarization state of the light incident on the display element can be favorably corrected to a predetermined polarization state, so that a decrease in light use efficiency in the display element can be suppressed. Furthermore, it is possible to reduce “light leakage” in which light can be seen from pixels that should not be visible when a stereoscopic image is displayed. As a result, an observer can observe a good stereoscopic image. As the half-wave plate, it is desirable to use a broadband wave plate having a laminated structure.

  As described above, the display element may alternately display the first image and the second image in a time division manner. If one of these images is a right-eye image and the other is a left-eye image, a stereoscopic image can be displayed without reducing the resolution. These images may be, for example, an image for a driver's seat observer and an image for a passenger's seat observer. Thus, the image display device of the present invention can be applied to various uses for displaying different images depending on the position of the observer.

  Hereinafter, a more specific configuration of the image display device according to the embodiment of the present invention will be described.

  In the image display device 130 of the present embodiment shown in FIG. 1, a polarizing plate 108, a display element 109, a polarizing plate 107, a shift element 106, a ballarax barrier 105, liquid crystal cells 104 and 103, a polarizing plate 102, and The light sources 101 are arranged in this order. The display element 109 has a plurality of pixels, and these pixels are divided into, for example, a first pixel group that displays an image for the right eye and a second pixel group that displays an image for the left eye. For example, the first pixels included in the first pixel group and the second pixels included in the second pixel group are alternately arranged. The parallax barrier 105 has stripe-shaped light transmission regions, and these light transmission regions are arranged so as to correspond to either the first pixel or the second pixel of the display element 109. In this embodiment, the polarization conversion element 100 includes a polarizing plate 102 as a polarizing element and liquid crystal cells 103 and 104 as polarization control elements.

  The light from the light source 101 first enters the polarizing plate 102. Of this light, only the component of linearly polarized light D that vibrates in the vertical direction with respect to the paper surface is transmitted through the polarizing plate 102.

  The linearly polarized light D from the polarizing plate 102 enters the liquid crystal cells 103 and 104 in order. Here, the liquid crystal cells 103 and 104 are each formed using a TN liquid crystal having a function of rotating 45 degrees of incident linearly polarized light. When no voltage is applied to either of the liquid crystal cells 103 and 104, the linearly polarized light D incident on the liquid crystal cells 103 and 104 is converted into linearly polarized light G that oscillates in a direction perpendicular to the paper surface and emitted. Further, when a voltage is applied to both the liquid crystal cells 103 and 104, the incident linearly polarized light D is emitted as it is in the polarization state. Furthermore, when a voltage is applied only to the liquid crystal cell 104, linearly polarized light having a polarization direction that forms an angle of 45 ° with the polarization direction of the incident linearly polarized light D is emitted.

  As the liquid crystal cells 103 and 104, birefringent liquid crystal cells that convert incident linearly polarized light into circularly polarized light may be used instead of liquid crystal cells using TN liquid crystal. Also in this case, when no voltage is applied to the liquid crystal cells 103 and 104, the linearly polarized light D incident on the liquid crystal cells 103 and 104 is converted into linearly polarized light G that oscillates in a direction perpendicular to the paper surface. When a voltage is applied to both 104, the incident linearly polarized light D is emitted as it is. Further, when a voltage is applied only to the liquid crystal cell 104, the incident linearly polarized light D is emitted as circularly polarized light F.

  The light emitted from the liquid crystal cells 103 and 104 enters the parallax barrier 105. The light transmitted through the light transmission region (opening) of the parallax barrier 105 is then incident on the polarization beam splitter (PBS) array 106. The PBS array 106 can shift the optical path of the incident light according to the polarization direction of the incident light. For example, P-polarized light is emitted from the PBS array without being shifted with respect to the polarization separation surface of the PBS array (first light), and S-polarized light is shifted by the PBS array with respect to the polarization separation surface of the PBS array. Are emitted (second light).

  One of the polarized lights (for example, the second light) emitted from the PBS array 106 is applied to the stripe-shaped optical path correction plate 111 and the half-wave plate 110 (whichever one is provided) corresponding to the light shielding region of the parallax barrier 106. Then, the light enters the polarizing plate 107 provided on the incident side of the display element 109. The optical path length and the polarization direction of the second light are corrected by the optical path correction plate 111 and the half-wave plate 110 to be equal to the optical path length and the polarization direction of the first light, respectively. On the other hand, the first light enters the polarizing plate 107 while maintaining the polarization state.

  The first light that has passed through the polarizing plate 107 enters one of the first pixel and the second pixel of the display element 109, and the second light enters the other. These lights are modulated in accordance with the image signal by the display element 109 and are emitted to the viewer side through the polarizing plate 108.

  FIG. 2 is a diagram for explaining the operation of the liquid crystal display element 109 and the parallax barrier 105 in the present embodiment. In FIG. 2, the PBS array 106 and the polarizing plates 107 and 108 are omitted for explanation.

  The liquid crystal display element 109 of the image display device 130 includes a plurality of pixels 120L and pixels 120R that are alternately arranged. As shown in FIG. 2, the light emitted from the opening of the pixel 120 </ b> L to the viewer side reaches the left eye of the viewer, but is blocked by the light-shielding region 105 b of the parallax barrier 105, so Will not reach. On the other hand, the light from the opening of the pixel 102R adjacent to the pixel 102L reaches the right eye, but does not reach the left eye because it is blocked by the light shielding region 105b of the parallax barrier 105. In this manner, a stereoscopic image can be displayed by displaying an image corresponding to the left eye on the pixel 120L and an image corresponding to the right eye on the pixel 120R.

  Next, the operation of the PBS array 106 will be described with reference to FIGS. The PBS array 106 has a plurality of polarization separation surfaces 112 arranged so as to correspond to the respective light transmission regions 105 a of the parallax barrier 105. Each polarization separation surface 112 transmits a specific linearly polarized light D that is P-polarized light with respect to the polarization separation surface, and reflects S-polarized light, that is, linearly polarized light G orthogonal to the linearly polarized light D, with respect to the polarization separation surface.

  As shown in FIG. 3A, when a voltage is applied to both the liquid crystal cells 103 and 104, the linearly polarized light D passes through the liquid crystal cells 103 and 104 while maintaining the polarization state, and is parallax. The light passes through the light transmission region 105a of the barrier 105 and passes through the corresponding polarization separation surface 112-A.

  As shown in FIG. 3B, when no voltage is applied to either of the liquid crystal cells 103 and 104, the linearly polarized light D is rotated by 90 ° by the liquid crystal cells 103 and 104 and then the parallax barrier 105. Through the light transmission region 105a, the light reaches the corresponding polarization separation surface 112-A. Since the light (linearly polarized light G) reaching the polarization separation surface 112-A becomes S-polarized light with respect to the polarization separation surface 112-A, as shown in the figure, the polarization separation surface 112-A and the polarization separation surface 112-A After being reflected by two surfaces of the adjacent polarization separation surface 112 -B, it is emitted from the PBS array 106. The emitted light has its optical path length corrected by the optical path correction plate 111 and then converted to P-polarized light by the half-wave plate 110.

  At this time, it seems to the observer that the parallax barrier 105 is shifted by the distance between the polarization separation plane diagram 112-A and the polarization separation plane diagram 112-B. Due to this shift, the pixel for the left eye becomes the pixel for the right eye, and the pixel for the right eye becomes the pixel for the left eye. When this switching is performed at high speed (for example, 120 Hz) and synchronized with the left-eye image and the right-eye image displayed on each pixel, a stereoscopic display is provided to the observer as if all pixels were displayed. Looks like it can be observed. Accordingly, it is possible to prevent a reduction in resolution, which has been a problem in displaying a stereoscopic image.

  Further, as shown in FIG. 3C, when a voltage is applied only to one liquid crystal cell (for example, the liquid crystal cell 104), the linearly polarized light D has an angle of 45 ° with the linearly polarized light D by the liquid crystal cell 104. It is converted into the linearly polarized light E formed, and enters the polarization separation surface 112-A of the PBS 106 at an angle of 45 ° with the polarization separation surface 112-A. In the polarization separation surface 112-A, incident light is decomposed into two components, a P-polarized component and an S-polarized component. The P-polarized light component passes through the polarization separation surface 112-A, passes through the first pixel of the display element, and reaches, for example, the right eye (E1). The S-polarized component is shifted by being reflected by the polarization separation surfaces 112-A and 112-B, passes through the optical path correction plate 111 and the half-wave plate 110, passes through the second pixel of the display element, for example, left Reach the eye (E2). Thus, the observer can always see all the pixels of the liquid crystal display element 109 with the right eye and the left eye. Therefore, when the display element 109 displays a two-dimensional image in accordance with the state of FIG. 3C (only the liquid crystal cell 104 is ON), the two-dimensional image can be displayed. Also in this case, there is no reduction in resolution as in the three-dimensional display of FIGS. 3 (a) and 3 (b).

  Even when a liquid crystal cell that converts incident linearly polarized light into circularly polarized light is used as the liquid crystal cells 103 and 104, as in the case shown in FIGS. Two-dimensional image display is possible. However, the light incident on the polarization separation surface 112-A of the PBS 106 when displaying a two-dimensional image is circularly polarized light.

  In FIG. 3, the half-wave plate 110 and the optical path correction plate 111 are stacked, but may be separately disposed. For example, the half-wave plate 110 may be disposed on the optical path of P-polarized light (first light). Further, optical path correction may be performed by the half-wave plate 110 itself.

  Since the image display device 130 has the above-described configuration, the apparent position of the parallax barrier 105 can be switched by controlling the polarization direction of the light incident on the PBS array 106, thereby improving the resolution. A good stereoscopic image can be displayed without lowering the image quality. Furthermore, switching between stereoscopic image display and two-dimensional image display can be easily performed.

  In the image display device 130, two liquid crystal cells 103 and 104 are used as the polarization control element, but one liquid crystal cell may be used. The operation of the image display apparatus when one liquid crystal cell is used as the polarization control element will be described below with reference to FIGS.

  4A and 4B, a liquid crystal cell that rotates the polarization direction of incident linearly polarized light by 90 ° is used as the liquid crystal cell 113. When a voltage is applied to the liquid crystal cell 113, P-polarized light (linearly polarized light D) is incident on the polarization separation surface 112-A and is transmitted through the polarization separation surface 112-A (FIG. 4A). On the other hand, when no voltage is applied to the liquid crystal cell 113, S-polarized light (linearly polarized light G) is incident on the polarization separation surface 112-A with respect to the polarization separation surface 112-A, and is adjacent to the polarization separation surface 112-A. Reflected by the polarization separation surface 112-B. As a result, the S-polarized light is shifted (FIG. 4B). Thus, by switching ON / OFF of the voltage applied to the liquid crystal cell 113, the light incident on the PBS array 106 can be switched between the P-polarized light and the S-polarized light with respect to the polarization separation surface 112. If this switching is performed at a high speed, a three-dimensional image with no reduction in resolution can be displayed.

  4C and 4D, a liquid crystal cell that rotates the polarization direction of incident linearly polarized light by 45 ° or changes the incident linearly polarized light into circularly polarized light is used as the liquid crystal cell 113. When a voltage is applied to the liquid crystal cell 113, P-polarized light (linearly polarized light D) is incident on the polarization separation surface 112-A and is transmitted through the polarization separation surface 112-A (FIG. 4C). On the other hand, when no voltage is applied to the liquid crystal cell 113, linearly polarized light E or circularly polarized light F that forms an angle of 45 ° with respect to the transmission axis of the polarization separation surface 112-A is incident on the polarization separation surface 112-A. Of the incident linearly polarized light E or circularly polarized light F, the P-polarized light component is transmitted through the polarized light separating surface 112-A and the S-polarized light component is polarized light separating surface 112-A and the polarized light separating surface 112-A. Reflected by the polarization separation surface 112-B. As a result, the S-polarized light component is shifted (FIG. 4D). In this way, by switching ON / OFF of the voltage applied to the liquid crystal cell 113, the light incident on the PBS array 106 is converted into P-polarized light (or S-polarized light) and 45 ° polarized light (or circularly polarized light) with respect to the polarization separation surface 112. Can be switched between. Therefore, switching between stereoscopic image display and two-dimensional image display is possible.

  The image display device 130 may have a microlens array on the opposite side of the parallax barrier 105 from the observer. FIG. 5A shows a configuration example in which the microlens 114 is arranged on the light incident side of the parallax barrier 105.

  As shown in FIG. 5A, each of the plurality of microlenses 115 included in the microlens array 114 corresponds to each light transmission region of the parallax barrier 105. With such a configuration, light emitted from each microlens 115 passes through the transparent support substrate 114 ′ of the microlens array 114 and is condensed on the light transmission region of the parallax barrier 105, and thus is emitted from a light source or the like. The proportion of the light transmitted through the light transmission region of the parallax barrier 105 can be increased. That is, the light cut in the light shielding region of the parallax barrier 105 can be used effectively, and the light use efficiency in the image display apparatus can be increased.

  The light transmission region of the parallax barrier 105 of the image display device 130 has a slit shape (opening slit). Therefore, as shown in FIG. 5B, the microlens array 114 includes a plurality of microlenses 115 arranged at the same pitch as the plurality of aperture slits of the parallax barrier 115, and the light shift direction by the shift element. That is, a lenticular lens having a condensing function is used in a plane perpendicular to the plurality of aperture slits (in the plane of the paper surface of FIG. 5A). Thereby, the light can be efficiently condensed on the light transmission region of the parallax barrier 105.

  As described above, when the microlens array 114 is used, a decrease in light utilization efficiency due to passing through the parallax barrier 105 can be suppressed, so that a brighter display can be obtained.

  According to the present invention, it is possible to provide a parallax barrier image display device in which the number of pixels of the display element is not increased, the resolution is not decreased, and the decrease in brightness is suppressed. The present invention can be suitably applied to, for example, an image display device that can switch between stereoscopic image display and two-dimensional image display. In this case, it is advantageous in that a decrease in resolution can be prevented both when displaying a stereoscopic image and when displaying a two-dimensional image. Further, the present invention is not limited to a stereoscopic image display device, and can be widely applied to display devices in which different displays are observed depending on the position of the observer.

It is sectional drawing which shows typically the three-dimensional image display apparatus of embodiment by this invention. It is a cross-sectional schematic diagram for demonstrating the effect | action of the liquid crystal display element and the parallax barrier in the three-dimensional image display apparatus of embodiment by this invention. (A)-(c) is a cross-sectional schematic diagram for demonstrating the effect | action of a liquid crystal cell and a PBS array. (A)-(d) is a cross-sectional schematic diagram for demonstrating the effect | action of a liquid crystal cell and a PBS array. (A) is a cross-sectional schematic diagram for demonstrating the effect | action of a microlens array, (b) is a perspective view of the microlens array shown to (a). It is sectional drawing which shows the conventional stereoscopic image display apparatus typically. It is sectional drawing which shows the other conventional stereo image display apparatus typically. (A)-(c) is a figure for demonstrating the structure of the stereo image display apparatus of embodiment by this invention. (A) And (b) is a figure for demonstrating the relationship between a shift element and a parallax barrier in the case of performing two-dimensional image display using the three-dimensional image display apparatus of embodiment by this invention. (A) is a figure which shows the state which displays a stereo image, (b) is a figure which shows the state which displays a two-dimensional image. (A) And (b) is a figure for demonstrating the state which displayed the stereo image. (A) And (b) is a figure which shows the state which displayed the stereo image, (c) is a figure which shows the state which displays a two-dimensional image. (A) is a figure which shows the state which displays a stereo image, (b) is a figure which shows the state which displays a two-dimensional image. (A) And (b) is a figure which shows the state which displays a stereo image, (c) is a figure which shows the state which displays a two-dimensional image. It is a figure for demonstrating arrangement | positioning of a parallax barrier and a display element. It is a figure for demonstrating the function of a polarization beam splitter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Polarization conversion element 101 Light source 102, 107, 108 Polarizing plate 103, 104 Liquid crystal cell 105 Parallax barrier 105a Light transmission area 105b Light shielding area 106 Shift element 109 Display element 110 1/2 wavelength plate 111 Optical path correction plate 112 Polarization separation surface 113 Liquid crystal cell 114 Micro lens array 120R, 120L Pixel

Claims (20)

Having a display element, a shift element and a parallax barrier in this order from the observer side,
The display element includes a first pixel group for displaying a first image and a second pixel group for displaying a second image;
The parallax barrier includes at least a plurality of light transmissive regions that transmit polarized light in a specific polarization state and a plurality of light shielding regions that shield polarized light in the specific polarization state, and each of the plurality of light transmissive regions is Arranged corresponding to each of the plurality of first pixels belonging to the first pixel group,
The shift element can shift the principal ray of light transmitted through each of the plurality of light transmission regions of the parallax barrier so as to correspond to each of the plurality of second pixels belonging to the second pixel group. , Image display device.   The shift element further includes a polarization conversion element capable of converting a polarization state of incident light on a side opposite to an observer of the shift element, and the shift element shifts the principal ray according to the polarization state of the principal ray. The image display device according to claim 1.   The polarization conversion element changes the polarization state of the first polarization emitted from the polarization element that emits the first polarization, and the second polarization having a polarization state different from the polarization state of the first polarization. The image display apparatus according to claim 2, further comprising a polarization control element capable of emitting light.   The image display apparatus according to claim 3, wherein the first polarized light emitted from the polarizing element is linearly polarized light, and the second polarized light is linearly polarized light having a polarization direction of approximately 45 ° with respect to the first polarized light.   The image display apparatus according to claim 3, wherein the first polarized light emitted from the polarizing element is linearly polarized light, and the second polarized light is circularly polarized light.   The image display device according to claim 3, wherein the first polarized light emitted from the polarizing element is linearly polarized light, and the second polarized light is linearly polarized light whose polarization direction is orthogonal to the first polarized light.   The polarization control element includes at least one liquid crystal cell, and the at least one liquid crystal cell changes a polarization state of incident polarization and a first state that maintains the polarization state of incident polarization according to an applied voltage. The image display device according to claim 3, wherein the image display device is switched between the second state and the second state. The polarization control element includes at least two liquid crystal cells, and the at least two liquid crystal cells change a polarization state of incident polarization and a first state that maintains a polarization state of incident polarization according to an applied voltage. Switching between the second state and rotating the polarization direction of the incident linearly polarized light by about 45 ° in the second state,
The first polarized light emitted from the polarizing element is linearly polarized light, and the polarization control element is configured to change the second polarized light orthogonal to the first polarized light when both the two liquid crystal cells are in the second state. The image display device according to claim 3, which emits light. The polarization control element includes at least two liquid crystal cells, and the at least two liquid crystal cells change a polarization state of incident polarization and a first state that maintains a polarization state of incident polarization according to an applied voltage. The second state to be switched, and function as a quarter wave plate in the second state,
The first polarized light emitted from the polarizing element is linearly polarized light, and the polarization control element is configured to change the second polarized light orthogonal to the first polarized light when both the two liquid crystal cells are in the second state. The image display device according to claim 3, which emits light.   The light emitted from the shift element passes through the shift element without being shifted, and is shifted by the shift element and the plurality of first light corresponding to each of the first pixel groups, The image display device according to claim 1, comprising a plurality of second lights corresponding to each of the pixel groups.   11. The optical path correction element according to claim 10, further comprising an optical path correction element that makes the optical path lengths of the plurality of first lights and the optical path lengths of the plurality of second lights the same between the shift element and the display element. Image display device.   The image display device according to claim 11, wherein the optical path correction element is provided on an optical path of the plurality of second lights.   The shift element includes a polarization beam splitter array, and the polarization beam splitter array has a plurality of polarization separation surfaces each transmitting or reflecting the principal ray according to a polarization state of the principal ray. The image display device according to claim 10.   The image display apparatus according to claim 13, wherein the polarization separation surface has a function of transmitting a P-polarized component with respect to the polarization separation surface and reflecting an S-polarization component with respect to the polarization separation surface.   A polarization correction element is further provided between the shift element and the display element, and the polarization correction element includes the plurality of first lights so that the plurality of first lights and the plurality of second lights are in the same polarization state. The image display device according to claim 10, wherein a polarization state of light and / or the plurality of second lights is corrected.   The image display according to claim 15, wherein the polarization correction element includes a half-wave plate, and is provided in an optical path of the plurality of first lights and / or an optical path of the plurality of second lights. apparatus.   A microlens array is further provided on the side opposite to the observer of the parallax barrier, and the microlens array has a plurality of microlenses corresponding to each of the plurality of light transmission regions of the parallax barrier. The image display device according to claim 1.   The image display device according to claim 17, wherein the microlens array is a lenticular lens.   The image display device according to claim 1, wherein the display element alternately displays the first image and the second image.   The image according to any one of claims 1 to 19, wherein the first image includes one of a right-eye image and a left-eye image, and the second image includes the other of them. Display device.

Images