Stereoscopic image display device

The present invention relates to a stereoscopic image display device that displays a stereoscopic image by projecting a parallax image to the left eye and the right eye of an observer.

Conventionally, there is known a stereoscopic image display device that realizes stereoscopic vision by providing a parallax image to the left and right eyes of an observer without using polarized glasses or the like. For example, it is provided with a light source that allows light to enter the observer's right eye and left eye independently, and a liquid crystal display element that alternately displays a right eye image and a left eye image in time, and switches the liquid crystal display element for display. A liquid crystal display device that realizes stereoscopic vision by switching the light source in synchronization with the above is known (see, for example, Patent Document 1).

As another conventional technique, a polarizing plate whose transmission axes are orthogonal to each other is arranged in front of the light source for the left eye and the light source for the right eye, and a polarizing plate whose transmission axes are orthogonal to each other for each horizontal line on the light source side of the liquid crystal display element is provided. By providing the liquid crystal display element to alternately display the left eye image and the right eye image for each horizontal line, the light from the right eye light source is incidented only on the horizontal line of the right eye image, and the light from the left eye light source is provided. There is known a liquid crystal display device that displays a stereoscopic image by incidenting light only on the horizontal line of the image for the left eye (see, for example, Patent Document 2).<patcit num="1"><text>Japanese Unexamined Patent Publication No. 8-262370</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 10-63199</text></patcit>

<p> However, in the display device according to Patent Document 1, it is necessary to switch between the image for the right eye and the image for the left eye at a high speed at a frequency that does not cause flicker. In this case, there is a problem that the switching responsiveness of the liquid crystal display element is insufficient, the image for the left eye is projected to the right eye of the observer, and the image for the right eye is projected to the left eye, causing crosstalk in the stereoscopic image.</p><p> Further, the display device according to Patent Document 2 can project only an image corresponding to half the resolution of the liquid crystal display element on each of the left eye and the right eye of the observer when the liquid crystal display element displays a two-dimensional image. There was a problem that a high-definition two-dimensional image could not be displayed.</p>

<p> In order to solve such a problem, the stereoscopic image display device according to the first embodiment of the present invention has a light source unit that independently and alternately projects unpolarized light toward the left eye and the right eye of the observer, and a light source unit for the left eye. An image display unit having a left-eye image display area for displaying a parallax image and a right-eye image display area for displaying a right-eye image alternately repeatedly in the vertical or horizontal direction, and light emitted from a light source unit incident on the left-eye image display area. When the light source unit projects light toward the observer's left eye, the light source unit causes the light emitted from the light source unit to enter the left eye image display area and the light source unit. When projecting light toward the observer's right eye, the light source unit and the transmission position switching unit are provided with a switching control unit that switches the light source unit and the transmission position switching unit at regular intervals so that the emitted light of the light source unit is incident on the right eye image display area.</p><p> Therefore, it is not necessary to switch the image of the image display unit at the same frequency as the switching frequency of the light source unit and the transmission position switching unit. Therefore, it is possible to switch whether to project light to the left eye or the right eye at high speed without being restricted by the responsiveness of the image display unit. As a result, the responsiveness of the moving image is excellent, and stereoscopic vision without flicker can be realized.</p><p> Further, in the stereoscopic image display device of the present embodiment, the transmission position switching unit converts the light from the light source unit toward the left eye image display area and the light from the light source unit toward the right eye image display area into linearly polarized light orthogonal to each other. An orthogonal polarization switching unit that alternately switches the direction of the linearly polarized light at regular intervals to emit light, and a transmission axis provided on the light source side of the image display unit and parallel to or orthogonal to the linearly polarized light emitted by the orthogonally polarized light switching unit. It may have an incident side polarizing plate having.</p><p> As a result, the light already directed in the direction of the left eye or the right eye is converted into linearly polarized light, so that the linearly polarized light does not need to be incident on the projection lens. As a result, the linearly polarized light orthogonal to each other does not collapse, and the polarizing plate on the incident side is filtered with high accuracy.</p><p> Further, in the stereoscopic image display device of the present embodiment, the orthogonally polarized light switching unit includes a polarizing plate and a polarized light rotating unit that switches between emitting linearly polarized light transmitted through the polarizing plate by rotating it by 90 ° and emitting it in the same direction. The left-eye image display area and the right-eye image display in the image display unit are the left-eye image-corresponding area that transmits the light projected on the left-eye image display area and the right-eye image-corresponding area that transmits the light projected on the right-eye image display area. One of the left-eye image-corresponding region and the right-eye image-corresponding region emits linearly polarized light emitted from the polarization rotating portion by rotating it by 90 °, and the other rotates the polarized light. It may include an orthogonal portion provided so as to emit linearly polarized light emitted from the portion in the same direction.</p><p> As a result, the direction of the linearly polarized light emitted from the orthogonal portion can be switched by the polarization rotating portion without delay in accordance with the switching of the light source portion. As a result, the image for the left eye or the image for the right eye is not projected in the wrong direction, so that the crosstalk of the stereoscopic image is reduced.</p><p> When the image display unit displays a two-dimensional image, the switching control unit may simultaneously project unpolarized light toward both eyes of the observer on the light source unit. As a result, the image displayed in the left-eye image display area and the image displayed in the right-eye image display area are alternately projected on each of both eyes. Therefore, when displaying a two-dimensional image, a high-definition image can be displayed at the maximum resolution of the image display unit.</p><p> Each time the image display unit updates the frame of the moving image, the switching control unit causes the light emitted from the light source unit to be incident on the left eye image display area and projected onto the observer's left eye, or incident on the right eye image display area. The light source unit and the transmission position switching unit may be controlled so as to switch whether to project to the right eye of the observer at least once. As a result, each image constituting the moving image can be provided to both eyes of the observer without exception.</p><p> The switching control unit determines whether the light emitted from the light source unit is incident on the left eye image display area and projected on the observer's left eye, or is incident on the right eye image display area and projected on the observer's right eye. You may switch at a frequency that is at least twice the refresh rate of. As a result, the frequency of the light projected on each of the left eye and the right eye becomes equal to or higher than the refresh rate of the image display unit, so that flicker does not occur.</p><p> Further, in the stereoscopic image display device of the present embodiment, the light source unit is a light source for the left eye that emits unpolarized light for the left eye, a light source for the right eye that emits unpolarized light for the right eye, and nothing emitted from the light source for the left eye and the light source for the right eye. A projection that projects the emitted light of a reflector that reflects polarized light and the light source for the left eye reflected by the reflector to the left eye of the observer, and projects the emitted light of the light source for the right eye reflected by the reflector to the right eye of the observer. It may have a lens.</p><p> As a result, the optical path from the light source for the left eye and the light source for the right eye to the projection lens is reflected by the reflector, so that the stereoscopic image display device is miniaturized. The light projected toward the observer is linearly polarized on the observer side of the reflector and the projection lens, and is not reflected or refracted until it is emitted from the image display unit. Therefore, the transmission position switching unit can reliably switch whether the emitted light of the light source unit is incident on the left-eye image display region or the right-eye image display region with highly accurate linearly polarized light.</p><p> The outline of the above invention does not list all the necessary features of the present invention, and a subcombination of these feature groups can also be an invention.</p>

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are the inventions. It is not always essential for development means.

FIG. 1 is an exploded perspective view showing the configuration of the stereoscopic image display device 10. The stereoscopic image display device 10 of the present embodiment aims to both display a clear stereoscopic image with less crosstalk and display a high-definition two-dimensional image.

The stereoscopic image display device 10 includes a light source unit 40, a transmission position switching unit 50, an image display unit 80, an emitting side polarizing plate 72, a switching control unit 90, and an image output unit 92. The light source unit 40 independently projects unpolarized light toward the left and right eyes of the observer. The light source unit 40 projects the light emitted from the left eye light source 42 that emits unpolarized light for the left eye, the right eye light source 44 that emits unpolarized light for the right eye, and the left eye light source 42 to the observer's left eye, and the right eye. It has a projection lens 46 that projects the light emitted from the light source 44 to the observer's right eye. The light source 42 for the left eye is arranged on the opposite side of the observer's left eye with respect to the optical axis of the projection lens 46, that is, on the right side when facing the observer. On the other hand, the light source 44 for the right eye is arranged on the side opposite to the observer's right eye with respect to the optical axis of the projection lens 46, that is, on the left side when facing the observer.

The projection lens 46 is, for example, a circular Fresnel lens. Alternatively, the projection lens 46 may include a linear Fresnel lens having a vertical ridge line and a linear Fresnel lens having a horizontal ridge line in an overlapping direction in the traveling direction of the light beam.

The image display unit 80 is a liquid crystal display element in which a liquid crystal material is sealed between two glass substrates having patterned transparent electrodes facing each other inward. The image display unit 80 has a left-eye image display area 82 for displaying a parallax image for the left eye and a right-eye image display area 84 for displaying a parallax image for the right eye alternately and repeatedly in the vertical or horizontal direction. Hereinafter, the image display unit 80 has the left-eye image display area 82 and the right-eye image display area 84 alternately and repeatedly in the vertical direction, and the orthogonal unit 66 has the left-eye image corresponding area on the odd-numbered horizontal line counting from the upper side. 67 will be described with the case where the right-eye image corresponding area 68 is provided on the even-numbered horizontal line.

The transmission position switching unit 50 includes an orthogonal polarization switching unit 60 and an incident side polarizing plate 70. The orthogonally polarized light switching unit 60 converts the light from the light source unit 40 toward the left-eye image display area 82 and the light from the light source unit 40 toward the right-eye image display area 84 into linearly polarized light orthogonal to each other, and also converts the linearly polarized light into linearly polarized light. Switch the direction and emit.

The orthogonal polarization switching unit 60 includes a polarizing plate 62, a polarization rotating unit 64, and an orthogonal portion 66. The polarizing plate 62 has a transmission axis in a uniform direction, and the unpolarized light emitted from the projection lens 46 is converted into linearly polarized light in a uniform direction and emitted. The polarization rotating unit 64 switches whether or not to rotate the polarization axis of linearly polarized light emitted from the polarizing plate 62 by 90 ° according to the applied voltage. For example, when no voltage is applied, the polarization rotating unit 64 rotates the linearly polarized light transmitted through the polarizing plate 62 by 90 ° and emits it. Then, when a predetermined voltage is applied from the switching control unit 90, the linearly polarized light transmitted through the polarizing plate 62 is emitted without changing the direction. The polarization rotating unit 64 is, for example, a liquid crystal panel having excellent switching responsiveness, and a liquid crystal material is enclosed between a pair of glass substrates having a pair of facing transparent electrodes formed inside. For example, a ferroelectric liquid crystal and an antiferroelectric liquid crystal.

The orthogonal portion 66 alternately has the left eye image corresponding region 67 and the right eye image corresponding region 68 in the same direction as the arrangement of the left eye image display region 82 and the right eye image display region 84 in the image display unit 80. The left-eye image corresponding area 67 transmits the light projected toward the left-eye image display area 82. The right-eye image corresponding area 68 transmits light projected toward the right-eye image display area 84. One of the left-eye image-corresponding region 67 and the right-eye image-corresponding region 68 rotates the linearly polarized light emitted from the polarization rotating portion 64 by 90 ° and emits the other, and the other emits the same linearly polarized light emitted from the polarization rotating portion 64. It is provided so that it emits in the direction.

The incident side polarizing plate 70 is provided on the light source unit 40 side of the image display unit 80, and has a transmission axis parallel to or orthogonal to the linearly polarized light emitted by the orthogonal polarization switching unit 60. Therefore, the incident side polarizing plate 70 blocks one of the linearly polarized light emitted from the orthogonal portion 66 and orthogonal to each other, and transmits the other. Then, only the linearly polarized light transmitted through the incident side polarizing plate 70 is incident on the image display unit 80. Hereinafter, a case where the transmission axis of the incident side polarizing plate 70 of this embodiment is orthogonal to the transmission axis of the polarizing plate 62 will be described.

The image display unit 80 emits the incident linearly polarized light rotated by 90 ° at a predetermined angle, for example, in the case of STN, in a state where no voltage is applied. The emitting side polarizing plate 72 is provided with a transmission axis parallel to or orthogonal to the transmission axis of the incident side polarizing plate 70, and blocks or transmits linearly polarized light emitted from the image display unit 80. The incident side polarizing plate 70, the image display unit 80, and the outgoing side polarizing plate 72 constitute a liquid crystal display 100. The angle formed by the transmission axes of the incident side polarizing plate 70 and the outgoing side polarizing plate 72 is set by either normally white or normally black on the liquid crystal display 100.

The orthogonal portion 66 is, for example, a patterned retardation filter. In the region where the linearly polarized light emitted from the polarization rotating unit 64 is rotated by 90 °, the optical spindle (phase-advancing axis or slow-phase axis) of the 1/2 retardation plate is deviated from the linearly polarized light emitted from the polarization rotating unit 64. Form at an angle of about 45 ° to the axis. Further, in the region where the linearly polarized light emitted from the polarization rotating portion 64 is emitted in the same direction, the optical spindle of the 1/2 retardation plate is parallel to the deflection axis of the linearly polarized light emitted from the polarization rotating portion 64. Or it is formed so as to be orthogonal. Such patterning is performed by imparting anisotropy according to the pattern to be formed to the orthogonal portion 66 by, for example, a photo-alignment method or a rubbing method. In the following embodiment, the left-eye image-corresponding region 67 emits linearly polarized light emitted from the polarization rotating portion 64 in the same direction, and the right-eye image-corresponding region 68 emits linearly polarized light emitted from the polarization rotating portion 64 in 90 directions. A case where the image is rotated by ° and emitted will be described.

The orthogonal polarization switching unit 60 converts unpolarized light that has already been directed in the direction of the left eye or the right eye into uniform linearly polarized light in the polarizing plate 62 at the stage of being emitted from the light source unit 40, and converts the uniform linearly polarized light into uniform linearly polarized light. At the orthogonal portion 66, it is converted into linearly polarized light that is orthogonal to each other. During this time, since there is no process of refracting or reflecting linearly polarized light, the orthogonally polarized light switching unit 60 emits highly accurate linearly polarized light. Therefore, the incident side polarizing plate 70 can reliably block one of the highly accurate linearly polarized light orthogonal to each other and efficiently transmit the other. That is, the transmission position switching unit 50 can accurately switch whether the emitted light of the light source unit 40 is incident on the left-eye image display area 82 or the right-eye image display area 84.

When the direction of the linearly polarized light emitted by the polarization rotating unit 64 is switched by 90 °, the direction of the linearly polarized light emitted from the left eye image corresponding area 67 and the right eye image corresponding area 68 is rotated by 90 °, respectively. As a result, of the linearly polarized light emitted from the left-eye image-corresponding region 67 and the right-eye image-corresponding region 68, which are orthogonal to each other, the linearly polarized light transmitted through the incident-side polarizing plate 70 is switched. That is, the linearly polarized light that was transmitted through the incident side polarizing plate 70 before the switching of the polarization rotating unit 64 is blocked, and the linearly polarized light that was blocked by the incident side polarizing plate 70 before the switching of the polarization rotating unit 64 is transmitted. .. Here, the polarization rotating unit 64 can switch the direction of the linearly polarized light incident on the orthogonal portion 66 without delay. Therefore, the transmission position switching unit 50 can switch whether the emitted light of the light source unit 40 is incident on the left-eye image display area 82 or the right-eye image display area 84 at the same time as the light source unit 40 is switched without delay. As a result, the image for the left eye or the image for the right eye is not projected to the opposite eye, so that the crosstalk of the stereoscopic image is reduced.

Hereinafter, the operation of the stereoscopic image display device 10 shown in FIG. 1 will be described with reference to FIGS. 2 to 5. 2 and 3 show the operation when the stereoscopic image display device 10 displays a stereoscopic image (hereinafter, referred to as 3D mode). The arrows shown on the front surface of each element in the figure indicate the direction of the emitted linearly polarized light. In the 3D mode, the switching control unit 90 instructs the image output unit 92 to output a parallax image. In response to this, the image output unit 92 outputs a parallax image for the left eye to the left eye image display area 82, and outputs a parallax image for the right eye to the right eye image display area 84.

In the state of FIG. 2, the switching control unit 90 turns on the light source 42 for the left eye and turns off the light source 44 for the right eye, and at the same time, does not apply a voltage to the polarization rotating unit 64. As a result, the linearly polarized light emitted from the polarizing plate 62 is rotated by 90 ° at the polarization rotating unit 64 and emitted. Then, the linearly polarized light incident on the left eye image corresponding region 67 is emitted from the left eye image corresponding region 67 in the same direction as at the time of incident, passes through the incident side polarizing plate 70, and is incident on the left eye image display region 82. Then, the parallax image for the left eye displayed in the left eye image display area 82 is projected and emitted from the emitting side polarizing plate 72 to reach the observer's left eye.

On the other hand, the linearly polarized light emitted from the polarization rotating unit 64 and incident on the right eye image corresponding region 68 is rotated by 90 ° in the right eye image corresponding region 68 and emitted, and is blocked by the incident side polarizing plate 70. As a result, the light emitted from the left-eye light source 42 does not reach the right-eye image display area 84. Therefore, the parallax image for the right eye displayed in the right eye image display area 84 is not projected on the left eye of the observer.

Next, as shown in FIG. 3, the switching control unit 90 turns off the light source 42 for the left eye and turns on the light source 44 for the right eye, and at the same time applies a predetermined voltage to the polarization rotating unit 64. As a result, the linearly polarized light emitted from the polarizing plate 62 is emitted in the same direction without being rotated by the polarization rotating unit 64. Then, the linearly polarized light incident on the right eye image corresponding region 68 is emitted by rotating 90 ° in the right eye image corresponding region 68, passes through the incident side polarizing plate 70, and is incident on the right eye image display region 84. Then, the parallax image for the right eye displayed in the right eye image display area 84 is projected and emitted from the emitting side polarizing plate 72 to reach the observer's right eye.

On the other hand, the linearly polarized light emitted from the polarization rotating portion 64 and incident on the left eye image corresponding region 67 is emitted from the left eye image corresponding region 67 in the same direction as at the time of incident, and is blocked by the incident side polarizing plate 70. As a result, the light emitted from the right-eye light source 44 does not reach the left-eye image display area 82. Therefore, the parallax image for the left eye displayed in the left eye image display area 82 is not projected on the left eye of the observer.

The switching control unit 90 projects the light emitted from the light source unit 40 into the left eye image display area 82 and projects it on the observer's left eye or the right eye each time the image display unit 80 updates the frame of the moving image. The light source unit 40 and the transmission position switching unit 50 are controlled so that the light source unit 40 and the transmission position switching unit 50 can be switched at least once to be incident on the image display area 84 and projected to the right eye of the observer. Therefore, each image constituting the moving image can be provided to both eyes of the observer without exception.

4 and 5 show the operation when the stereoscopic image display device 10 displays a two-dimensional image (hereinafter referred to as 2D mode). When the image display unit 80 displays a two-dimensional image, the switching control unit 90 causes the light source unit 40 to simultaneously project unpolarized light toward both eyes of the observer. That is, the switching control unit 90 turns on both the light source 42 for the left eye and the light source 44 for the right eye in the 2D mode. Then, whether or not to apply a voltage to the polarization rotating unit 64 is switched at regular intervals. For example, in the state shown in FIG. 4, the switching control unit 90 does not apply a voltage to the polarization rotating unit 64. In this state, the light emitted from the left-eye light source 42 and the right-eye light source 44 enters the odd-numbered row of horizontal lines of the image display unit 80, that is, the left-eye image display area 82, and reaches both eyes of the observer. In this case, no light is incident on the even-numbered rows of the image display unit 80.

On the other hand, in the state shown in FIG. 5, the switching control unit 90 applies a voltage to the polarization rotating unit 64. As a result, the light emitted from the left-eye light source 42 and the right-eye light source 44 enters the even-numbered rows of the horizontal lines of the image display unit 80, that is, the right-eye image display area 84, and reaches both eyes of the observer. In this case, no light is incident on the odd numbered rows of the image display unit 80, that is, the left eye image display area 82. Therefore, in the 2D mode, the odd-numbered line 2D image displayed in the left-eye image display area 82 and the even-numbered line 2D image displayed in the right-eye image display area 84 are alternately projected onto the observer's left eye and right eye, respectively. Will be done.

Here, the human eye recognizes light having a frequency of less than 50 to 60 Hz as flicker. Therefore, the refresh rate of the image display unit 80 is, for example, 60 Hz, which does not recognize flicker. On the other hand, the switching control unit 90 causes the light emitted from the light source unit 40 to be incident on the left eye image display area 82 and projected onto the observer's left eye, or is incident on the right eye image display area 84 and is incident on the observer's right eye. The projection rate is switched at least twice the refresh rate of the image display unit 80, that is, at a frequency of 120 Hz. Therefore, the frequency of the light projected on each of the left eye and the right eye becomes equal to or higher than the refresh rate of the image display unit 80, and flicker does not occur. By the above operation, the stereoscopic image display device 10 can display a high-definition image with the maximum resolution of the image display unit 80 when displaying a two-dimensional image.

FIG. 6 shows an example of the configuration when the stereoscopic image display device 10 includes the reflector 48. In the stereoscopic image display device 10 of this embodiment, the light source unit 40 includes a reflector 48 in addition to the configuration shown in FIG. The reflector 48 reflects the unpolarized light emitted from the light source 42 for the left eye and the light source 44 for the right eye. The projection lens 46 projects the emitted light of the left-eye light source 42 reflected by the reflector 48 to the observer's left eye, and projects the emitted light of the right-eye light source 44 reflected by the reflector 48 to the observer's right eye. .. According to such a configuration, the reflector 48 reflects the optical path from the light source 42 for the left eye and the light source 44 for the right eye to the projection lens 46, so that the stereoscopic image display device 10 is miniaturized. The light projected toward the observer is linearly polarized on the observer side of the reflector 48 and the projection lens 46, and is not reflected or refracted until it is emitted from the image display unit 80. Therefore, the transmission position switching unit 50 can reliably switch whether the emitted light of the light source unit 40 is incident on the left eye image display area 82 or the right eye image display area 84 with highly accurate linearly polarized light.

The stereoscopic image display device 10 of this embodiment further includes a diffuser plate 120 on the front surface of the liquid crystal display 100. The diffuser plate 120 diffuses the image light emitted from the liquid crystal display 100 in the vertical direction. The diffuser plate 120 does not diffuse the image light emitted from the liquid crystal display 100 in the horizontal direction. As a result, the viewing angle of the stereoscopic image display device 10 can be widened in the vertical direction without increasing the crosstalk in the 3D mode.

As is clear from the above description, according to the stereoscopic image display device 10 of the present embodiment, it is possible to both display a clear stereoscopic image with less crosstalk and display a high-definition two-dimensional image.

In the above embodiment, the left-eye image-corresponding region 67 emits linearly polarized light emitted from the polarization rotating portion 64 in the same direction, and the right-eye image-corresponding region 68 emits linearly polarized light emitted from the polarization rotating portion 64. The operation of the stereoscopic image display device 10 when the image is emitted by rotating the image by 90 ° has been described. However, the configuration and operation of the stereoscopic image display device 10 are not limited to this. For example, the left-eye image-corresponding region 67 emits the linearly polarized light emitted from the polarization rotating portion 64 by rotating it by 90 °, and the right-eye image-corresponding region 68 emits the linearly polarized light emitted from the polarization rotating portion 64 in the same direction. It may be emitted. In this case, the switching control unit 90 applies a voltage to the polarization rotating unit 64 when turning on the light source 42 for the left eye in the 3D display mode, and transmits the linear deflection emitted from the polarizing plate 62 in the same direction. .. Then, when the light source 44 for the right eye is turned on, no voltage is applied to the polarized light rotating unit 64, and the linearly polarized light emitted from the polarizing plate 62 is rotated by about 90 ° and emitted. As a result, the same effect as that of the examples described in FIGS. 2 to 6 is obtained.

Further, as yet another embodiment, the transmission axis of the incident side polarizing plate 70 may be provided parallel to the transmission axis of the polarizing plate 62. Then, the left-eye image-corresponding region 67 emits the linearly polarized light emitted from the polarizing rotation unit 64 in the same direction, and the right-eye image-corresponding region 68 rotates the linearly polarized light emitted from the polarizing rotation unit 64 by 90 °. When emitting light, the switching control unit 90 applies a voltage to the polarization rotating unit 64 when turning on the light source 42 for the left eye in the 3D display mode, and directs the linear deflection emitted from the polarizing plate 62 as it is. To make it transparent. Then, when the light source 44 for the right eye is turned on, no voltage is applied to the polarized light rotating unit 64, and the linearly polarized light emitted from the polarizing plate 62 is rotated by about 90 ° and emitted. As a result, the same effect as that of the examples described in FIGS. 2 to 6 is obtained.

Further, the transmission axes of the polarizing plate 62 and the incident side polarizing plate 70 are parallel, and the left-eye image-corresponding region 67 emits the linearly polarized light emitted from the polarization rotating portion 64 by rotating it by 90 °, and the right-eye image-corresponding region 67. 68 may emit the linearly polarized light emitted from the polarizing rotation unit 64 in the same direction. In this case, in the 3D display mode, the switching control unit 90 does not apply a voltage to the polarization rotating unit 64 when turning on the light source 42 for the left eye, and rotates the linear deflection emitted from the polarizing plate 62 by about 90 °. Exit. Then, when the light source 44 for the right eye is turned on, a voltage is applied to the polarized light rotating unit 64 to transmit the linearly polarized light emitted from the polarizing plate 62 in the same direction. As a result, the same effect as that of the examples described in FIGS. 2 to 6 is obtained.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that the form with such changes or improvements is also included in the technical scope of the present invention.

<figref num="1">It is an exploded perspective view which shows the structure of 3D image display apparatus 10.</figref><figref num="2">It is a figure which shows the operation of the stereoscopic image display device 10 in a 3D mode.</figref><figref num="3">It is a figure which shows the operation of the stereoscopic image display device 10 in a 3D mode.</figref><figref num="4">It is a figure which shows the operation of the stereoscopic image display device 10 in a 2D mode.</figref><figref num="5">It is a figure which shows the operation of the stereoscopic image display device 10 in a 2D mode.</figref><figref num="6">FIG. 5 is a side perspective view showing an example of a configuration when the stereoscopic image display device 10 includes a reflector 48.</figref>

Code description

10 ... 3D image display device, 40 ... Light source unit, 42 ... Left eye light source, 44 ... Right eye light source, 46 ... Projection lens, 48 ... Reflector, 50 ... Transmission position switching part, 60 ... orthogonal polarization switching part, 62 ... polarizing plate, 64 ... polarization rotating part, 66 ... orthogonal part, 67 ... left eye image compatible area, 68 ... right eye Image-corresponding area, 70: Incident-side polarizing plate, 72: Exit-side polarizing plate, 80: Image display unit, 82: Left-eye image display area, 84: Right-eye image display area, 90. Switching control unit, 92 image output unit, 100 liquid crystal display, 120 diffuser