JP2012088721A - Display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display equipped with a phase difference element that is unlikely to cause an imbalance.SOLUTION: A phase difference element provided on a surface of a display panel comprises: a base film that has optical anisotropy; and a phase difference layer that is formed on a surface on the display panel side of the base film and that has optical anisotropy. The phase difference layer comprises two types of phase difference areas whose slow axes face a different direction from each other. The two types of phase difference areas are regularly arranged in an adjacent manner in an in-plane direction of the base film, and include a slow axis, respectively, in a direction intersecting with a boundary line between the adjacent phase difference areas at an angle other than an orthogonal angle. The base film includes a slow axis in a direction parallel or orthogonal to the boundary line. Each bisector of the slow axis in one type of phase difference area and of the slow axis in the other type of phase difference area is parallel to the slow axis of the base film. The two types of phase difference areas have retardation equivalent to λ/4, respectively.

Description

  The present invention relates to a display device including a phase difference element having optical anisotropy, and more particularly, to a display device including a phase difference element that is suitably used for stereoscopic image observation using polarized glasses.

  2. Description of the Related Art Conventionally, there is a type of stereoscopic image display device that uses polarized glasses that emits light in different polarization states between a left-eye pixel and a right-eye pixel. In such a display device, the viewer wears polarized glasses, and then the light emitted from the left-eye pixel is incident only on the left eye, and the light emitted from the right-eye pixel is incident only on the right eye, thereby providing a stereoscopic image. Can be observed.

  For example, in Patent Document 1, a phase difference element is used to emit light having different polarization states between a left-eye pixel and a right-eye pixel. In this phase difference element, a piece-like phase difference member having a slow axis or a phase advance axis in one direction is provided corresponding to the pixel for the left eye, and the slow axis or the phase difference member in a direction different from the piece-like phase difference member is provided. A flaky phase difference member having a fast axis is provided corresponding to the right-eye pixel.

Japanese Patent No. 3360787

  In the above display device, it is desirable that the left-eye image light emitted from the left-eye pixel is incident only on the left eye, and the right-eye image light emitted from the right-eye pixel is incident only on the right eye. However, there is a problem called ghost, in which the image light for the left eye is slightly incident on the right eye or the image light for the right eye is slightly incident on the left eye.

  In particular, in the display device described in Patent Document 1, when the substrate is made of a plastic film, the ghost is strong only in the left eye or the right eye due to optical anisotropy slightly present in the substrate. There is a risk of seeing. There may also be a problem that the color of the video is different between the left eye and the right eye. When such an imbalance occurs, it becomes difficult to observe a stereoscopic image, or the viewer feels uncomfortable.

  In addition, the problem of imbalance does not occur only in a stereoscopic image display device, but is common in a phase difference element that separates incident light into light of two or more polarization states and a device that uses such a phase difference element. This is what happens.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a display device including a phase difference element in which unbalance is unlikely to occur.

  A display device of the present invention includes a display panel driven based on an image signal, a backlight unit that illuminates the display panel, and a phase difference element provided on the opposite side of the backlight unit in relation to the display panel. It is equipped with. The retardation element incorporated in this display device has a substrate film having optical anisotropy and a retardation layer formed on the surface of the substrate film on the display panel side and having optical anisotropy. is doing. The retardation layer has two types of retardation regions having different slow axis directions. The two types of retardation regions are regularly arranged adjacent to each other in the in-plane direction of the base film. Each phase difference region has a slow axis in a direction intersecting with a boundary line between adjacent phase difference regions at an angle other than orthogonal. The base film has a slow axis in a direction parallel to or perpendicular to the boundary line. Of the two types of phase difference regions, the slow axis of one type of phase difference region is the first slow axis, and the slow axis of the other type of phase difference region is the second slow axis. In the case of the phase axis, the bisector of the first slow axis and the second slow axis and the slow axis of the base film are parallel to each other. Each of the two types of retardation regions has a retardation of λ / 4.

  In the display device of the present invention, two types of retardation regions having different slow axis directions are regularly arranged adjacent to each other in the in-plane direction of the base film. Thereby, for example, light incident from the phase difference region side is separated into two types of light having different polarization states, and then passes through the base film. Here, each retardation region has a slow axis in a direction intersecting with the boundary line at an angle other than perpendicular, and the base film has a slow axis in a direction parallel to or perpendicular to the boundary line. Yes. Therefore, the influence due to the optical anisotropy of the base film extends to each light transmitted through the base film, and extremely large only to one kind of light of two types of light transmitted through the base film. There is nothing.

  According to the display device of the present invention, the influence caused by the optical anisotropy of the base film affects each light transmitted through the base film, and one of the two types of light transmitted through the base film. I tried not to reach the light. Thereby, for example, it is possible to reduce unbalance such that a ghost appears strong only to the left eye or the right eye, or the color of the video is different between the left eye and the right eye. Accordingly, it is possible to realize a display device in which unbalance is unlikely to occur.

1 is a cross-sectional view illustrating an example of a configuration of a display device according to an embodiment of the present invention. It is a conceptual diagram for demonstrating the transmission axis and slow axis in the display apparatus of FIG. FIG. 2 is a configuration diagram illustrating an example of a configuration of a phase difference element in FIG. 1 and a slow axis. FIG. 3 is a configuration diagram illustrating another example of the configuration of the phase difference element in FIG. 1 and a slow axis. FIG. 2 is a system diagram illustrating a relationship between the display device of FIG. 1 and polarized glasses. It is a conceptual diagram for demonstrating an example of the transmission axis and slow axis at the time of observing the image | video of the display apparatus of FIG. 1 with a right eye. It is a conceptual diagram for demonstrating the other example of the transmission axis at the time of observing the image | video of the display apparatus of FIG. 1 with a right eye. It is a conceptual diagram for demonstrating an example of the transmission axis at the time of observing the image | video of the display apparatus of FIG. 1 with a left eye. It is a conceptual diagram for demonstrating the other example of the transmission axis at the time of observing the image | video of the display apparatus of FIG. 1 with a left eye. FIG. 6 is a configuration diagram illustrating another example of the phase difference element in FIG. 1. FIG. 6 is a configuration diagram illustrating another example of the phase difference element in FIG. 1. FIG. 6 is a configuration diagram illustrating still another example of the phase difference element in FIG. 1. It is a block diagram showing about the other example of the display apparatus of FIG. It is a block diagram showing about the other example of the display apparatus of FIG. It is a characteristic view showing retardation of the retardation film of polarized glasses. It is a characteristic view showing the retardation of the area | region for right eyes, and the area | region for left eyes. It is a characteristic view showing the retardation of a base film. It is a characteristic view showing the extinction ratio of an Example and a comparative example. It is a distribution diagram showing wavelength distribution when not using polarized glasses. It is a characteristic view showing the chromaticity of an Example and a comparative example.

Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings. The description will be given in the following order.

1. Embodiment (display device, phase difference element)
2. Modification (display device, phase difference element)
3. Example (display device)

  FIG. 1 illustrates a cross-sectional configuration of a display device according to an embodiment of the present invention. Note that the phase difference element according to one embodiment of the present invention will be described by exemplifying the case where it is incorporated in the display device of this embodiment.

[Configuration of Display Device 1]
The display device 1 according to the present embodiment is a polarizing glasses type display device that displays a stereoscopic image to an observer (not shown) wearing polarized glasses 2 described later in front of an eyeball. This display device 1 is configured by laminating a backlight unit 10, a liquid crystal display panel 20 (display panel), and a retardation element 30 in this order. In the display device 1, the surface of the phase difference element 30 is an image display surface and is directed toward the observer side. In the present embodiment, it is assumed that display device 1 is arranged so that the video display surface is parallel to the vertical surface (vertical surface). The video display surface is rectangular, and the longitudinal direction of the video display surface is parallel to the horizontal direction (y-axis direction in the figure). In addition, it is assumed that the observer wears the polarizing glasses 2 in front of the eyeball and observes the video display surface.

[Backlight unit 10]
The backlight unit 10 includes, for example, a reflecting plate, a light source, and an optical sheet (all not shown). The reflection plate returns the light emitted from the light source to the optical sheet side, and has functions such as reflection, scattering, and diffusion. This reflector is made of, for example, foamed PET (polyethylene terephthalate). Thereby, the emitted light from the light source can be used efficiently. The light source illuminates the liquid crystal display panel 20 from behind. For example, a plurality of linear light sources are arranged in parallel at equal intervals, or a plurality of point light sources are two-dimensionally arranged. Examples of the linear light source include a hot cathode fluorescent lamp (HCFL) and a cold cathode fluorescent lamp (CCFL). Examples of the point light source include a light emitting diode (LED). The optical sheet equalizes the in-plane luminance distribution of light from the light source, or adjusts the divergence angle and polarization state of light from the light source within a desired range. For example, a diffusion plate, a diffusion sheet, A prism sheet, a reflective polarizing element, a phase difference plate, and the like are included.

[LCD panel 20]
The liquid crystal display panel 20 is a transmissive display panel in which a plurality of pixels are two-dimensionally arranged in a row direction and a column direction, and displays an image by driving each pixel according to a video signal. For example, as shown in FIG. 1, the liquid crystal display panel 20 includes a polarizing plate 21 </ b> A, a transparent substrate 22, a pixel electrode 23, an alignment film 24, a liquid crystal layer 25, an alignment film 26, in common from the backlight unit 10 side. It has the electrode 27, the color filter 28, the transparent substrate 29, and the polarizing plate 21B.

  Here, the polarizing plate 21 </ b> A is a polarizing plate disposed on the light incident side of the liquid crystal display panel 20, and the polarizing plate 21 </ b> B is a polarizing plate disposed on the light emission side of the liquid crystal display panel 20. The polarizing plates 21A and 21B are a kind of optical shutter, and allow only light (polarized light) in a certain vibration direction to pass therethrough. Each of the polarizing plates 21A and 21B is disposed, for example, such that the polarization axes are different from each other by a predetermined angle (for example, 90 degrees), whereby the light emitted from the backlight unit 10 is transmitted through the liquid crystal layer, Or it is cut off.

  The direction of the transmission axis (not shown) of the polarizing plate 21 </ b> A is set within a range in which light emitted from the backlight unit 10 can be transmitted. For example, when the polarization axis of light emitted from the backlight unit 10 is in the vertical direction, the transmission axis AX4 is also oriented in the vertical direction, and the polarization axis of light emitted from the backlight unit 10 is horizontal. In the case of the direction, the transmission axis AX4 also faces the horizontal direction. The light emitted from the backlight unit 10 is not limited to linearly polarized light, and may be circularly polarized light, elliptically polarized light, or non-polarized light.

  The direction of the polarization axis AX4 of the polarizer 21B is set within a range in which light transmitted through the liquid crystal display panel 20 can be transmitted. For example, when the orientation of the polarization axis (not shown) of the polarizer 21A is horizontal, the polarization axis AX4 is oriented in the direction (vertical direction) perpendicular thereto, and the polarization axis of the polarizer 21A When the orientation is the vertical direction, the polarization axis AX4 is oriented in a direction (horizontal direction) perpendicular thereto.

  The transparent substrates 22 and 29 are generally substrates that are transparent to visible light. The transparent substrate on the backlight unit 10 side is formed with an active drive circuit including, for example, a TFT (Thin Film Transistor) as a drive element electrically connected to the transparent pixel electrode and a wiring. ing. The pixel electrode 23 is made of indium tin oxide (ITO), for example, and functions as an electrode for each pixel. The alignment film 24 is made of, for example, a polymer material such as polyimide, and performs an alignment process on the liquid crystal. The liquid crystal layer 25 is made of, for example, VA (Virtical Alignment) mode, TN (Twisted Nematic) mode, or STN (Super Twisted Nematic) mode liquid crystal. The liquid crystal layer 25 has a function of transmitting or blocking light emitted from the backlight unit 10 for each pixel by an applied voltage from a drive circuit (not shown). The common electrode 27 is made of, for example, ITO and functions as a common counter electrode. The color filter 28 is formed by arranging filter portions 28A for separating the light emitted from the backlight unit 10 into, for example, three primary colors of red (R), green (G), and blue (B). Yes. In this color filter 29, the filter portion 28A is provided with a black matrix portion 28B having a light shielding function at a portion corresponding to the boundary between pixels.

[Phase difference element 30]
Next, the phase difference element 30 will be described. FIG. 3A is a perspective view showing an example of the configuration of the phase difference element 30 of the present embodiment. FIG. 3B shows the slow axis of the phase difference element 30 in FIG. Similarly, FIG. 4A is a perspective view showing another example of the configuration of the phase difference element 30 of the present embodiment. FIG. 4B shows the slow axis of the phase difference element 30 of FIG. Note that the retardation element 30 shown in FIGS. 3A and 3B and the retardation element 30 shown in FIGS. 4A and 4B are the slow axis AX3 of the base film 31 (described later). Is different in terms of the direction.

  The phase difference element 30 changes the polarization state of the light transmitted through the polarizer 21 </ b> B of the liquid crystal display panel 20. The retardation element 30 includes, for example, a base film 31 and a retardation layer 32 as shown in FIG.

  The base film 31 is made of a thin resin film having optical anisotropy. As the resin film, one having a small optical anisotropy, that is, a birefringence is preferable. Examples of resin films having such characteristics and often used commercially include TAC (triacetyl cellulose), COP (cycloolefin polymer), PMMA (polymethyl methacrylate), and the like. . Here, examples of the COP include ZEONOR (trademark of Nippon Zeon Co., Ltd.) and Arton (trademark of JSR Corporation). The retardation of the base film 31 is preferably 20 nm or less, and more preferably 10 nm or less.

  The slow axis AX3 of the base film 31 is oriented in the horizontal direction or the vertical direction, for example, as shown in FIGS. More specifically, the slow axis AX3 faces the same direction as the longitudinal direction or the short direction of the right eye region 32A and the left eye region 32B, as can be seen from the description of the retardation layer 32 described later. The direction is the same as or perpendicular to the direction of the boundary line L1. Further, it is preferable that the slow axis AX3 is in a direction intersecting with the slow axes AX1 and AX2, and is in a direction parallel to the bisector of the slow axis AX1 and the slow axis AX2.

  The retardation layer 32 is a thin layer having optical anisotropy. The retardation layer 32 is provided on the surface of the base film 31 and is attached to the light emitting surface (polarizing plate 21 </ b> B) of the liquid crystal display panel 20. The retardation layer 32 has two types of retardation regions (right-eye region 32A and left-eye region 32B) having different slow axis directions. The right eye region 32A of the present embodiment corresponds to a specific example of “one type of phase difference region” of the present invention, and the left eye region 32B of the present embodiment corresponds to “the other type of phase difference region” of the present invention. This corresponds to a specific example of “phase difference region”.

  The right-eye region 32A and the left-eye region 32B have, for example, a belt-like shape extending in one common direction (horizontal direction) as shown in FIGS. 1, 3A, and 4A. It has become. The right eye region 32A and the left eye region 32B are regularly arranged adjacent to each other in the in-plane direction of the base film 31, and specifically, the short sides of the right eye region 32A and the left eye region 32B. They are alternately arranged in the direction (vertical direction). Therefore, the boundary line L1 in which the right eye region 32A and the left eye region 32B are adjacent to (in contact with) each other is oriented in the same direction as the longitudinal direction (horizontal direction) of the right eye region 32A and the left eye region 32B.

  As shown in FIGS. 3 to 4, the right-eye region 32 </ b> A extends in a direction that intersects the boundary line L <b> 1 with the adjacent left-eye phase difference region 32 </ b> B at an angle θ <b> 1 (0 ° <θ1 <90 °). It has a slow axis AX1. On the other hand, as shown in FIGS. 2 to 4, the left-eye region 32B intersects the boundary line L1 with the adjacent right-eye phase difference region 32A at an angle θ2 (0 ° <θ2 <90 °) other than orthogonal. The slow axis AX2 is in a direction different from the direction of the slow axis AX1.

  Here, the “direction different from the direction of the slow axis AX1” not only means that the direction of the slow axis AX1 is different from the direction of the slow axis AX1, but also the slow axis AX1 with respect to the boundary line L1. Means rotating in the opposite direction. That is, the slow axes AX1, AX2 rotate in different directions across the boundary line L1. The angle θ1 of the slow axis AX1 and the angle θ2 of the slow axis AX2 are preferably equal to each other as absolute values (when the rotational direction is not taken into consideration). However, these may be slightly different from each other due to a manufacturing error or the like, and may be different from each other at an angle larger than the manufacturing error in some cases. The manufacturing error described above varies depending on the technique for manufacturing the right-eye region 32A and the left-eye region 32B, but is about 5 ° at the maximum, for example.

  In the future, unless otherwise specified, the case where the polarized glasses 2 are of the circularly polarized type and the display device 1 is a display device for circularly polarized glasses will be mentioned. In this case, for example, the angles θ1 and θ2 are preferably such that the angle θ1 is + 45 ° and the angle θ2 is −45 °.

  Further, as shown in FIGS. 2 to 4, the slow axes AX1 and AX2 face the direction intersecting with both the horizontal direction and the vertical direction, and also intersect with the slow axis AX3 of the base film 31. Facing the direction. Further, it is preferable that the slow axes AX1 and AX2 are oriented in a direction in which a bisector of the slow axis AX1 and the slow axis AX2 faces a direction parallel to the boundary line L1.

  Further, the slow axes AX1 and AX2 face the direction intersecting with the polarization axis AX4 of the polarizing plate 21B of the liquid crystal display panel 20 as shown in FIGS. Further, the slow axis AX1 is in the same direction as the slow axis AX5 of the retardation film 21B for the right eye of the polarizing glasses 2 to be described later, or in the direction corresponding to the direction, and the retardation film for the left eye. The direction is different from the direction of the slow axis AX6 of 22B. On the other hand, the slow axis AX2 is in the same direction as the direction of the slow axis AX6 or in a direction corresponding to that direction, and is in a direction different from the direction of the slow axis AX5.

[Polarized glasses 2]
Next, the polarized glasses 2 will be described. FIG. 5 is a perspective view showing an example of the configuration of the polarizing glasses 2 together with the display device 1. The polarized glasses 2 are worn in front of an eyeball of an observer (not shown), and are used by the observer when observing an image displayed on the image display surface. The polarized glasses 2 include, for example, right eye glasses 41 and left eye glasses 42 as shown in FIG.

  The right eyeglasses 41 and the left eyeglasses 42 are arranged to face the video display surface of the display device 1. The right eyeglasses 41 and the left eyeglasses 42 are preferably arranged in one horizontal plane as much as possible as shown in FIG. 5, but may be arranged in a slightly inclined flat surface.

  The right eyeglasses 41 include, for example, a polarizing plate 41A and a right eye retardation film 41B. On the other hand, the left-eye glasses 42 include, for example, a polarizing plate 42A and a left-eye retardation film 42B. The right-eye retardation film 41B is the surface of the polarizing plate 41A and provided on the light incident side. The left-eye retardation film 42B is the surface of the polarizing plate 42A and provided on the light incident side.

  The polarizing plates 41A and 42A are disposed on the light exit side of the polarizing glasses 2 and allow only light (polarized light) in a certain vibration direction to pass therethrough. The polarization axes AX7 and AX8 of the polarizing plates 41A and 42A are oriented in the direction orthogonal to the polarization axis AX4 of the polarizing plate 21B, respectively. For example, as shown in FIGS. 2A and 2B, the polarization axes AX7 and AX8 are oriented horizontally when the polarization axis AX4 is oriented vertically, and the polarization axis AX4 is oriented horizontally. When facing the direction, it is facing the vertical direction.

  The right-eye retardation film 41B and the left-eye retardation film 42B are thin layers having optical anisotropy. As shown in FIG. 2, the slow axis AX5 of the right-eye retardation film 41B and the slow axis AX6 of the left-eye retardation film 42B are oriented in a direction intersecting with both the horizontal direction and the vertical direction. Further, it faces the direction intersecting with the polarization axes AX7 and AX8 of the polarizing plates 41A and 42A. Moreover, it is preferable that the slow axes AX5 and AX6 are oriented in a direction in which the bisector of the slow axes AX5 and AX6 faces the direction perpendicular to the boundary line L1. Further, the slow axis AX5 is in the same direction as the direction of the slow axis AX1, or in a direction corresponding to that direction, and is in a direction different from the direction of the slow axis AX2. On the other hand, the slow axis AX6 is in the same direction as the slow axis AX2 or in a direction corresponding to that direction, and is in a direction different from the direction of the slow axis AX1.

[Retardation]
By the way, when observed using the polarized glasses 2, for example, as shown in FIGS. 6A and 6B, FIGS. 7A and 7B, the right eye pixel image is recognized by the right eye. It is necessary to prevent the left eye from recognizing the image of the right eye pixel. At the same time, for example, as shown in FIGS. 8A, 8B, 9A, and 9B, the image of the left-eye pixel can be recognized in the left eye, and the left-eye pixel can be recognized in the right eye. It is necessary to make the image unrecognizable. For this purpose, as shown below, it is preferable to set the retardation of the right-eye region 32A and the right-eye retardation film 41B and the retardation of the left-eye region 32B and the left-eye retardation film 42B.

  Specifically, it is preferable that one of the retardations of the right-eye region 32A and the left-eye region 32B is + λ / 4 and the other is −λ / 4. Here, the signs of retardation being reversed indicate that the directions of the slow axes differ by 90 °. At this time, the retardation of the right-eye retardation film 41B is preferably the same as the retardation of the right-eye region 32A, and the retardation of the left-eye retardation film 42B is the same as the retardation of the left-eye region 32B. Is preferred.

[basic action]
Next, an example of a basic operation when displaying an image in the display device 1 of the present embodiment will be described with reference to FIGS.

  First, in a state where light emitted from the backlight unit 10 is incident on the liquid crystal display panel 20, a parallax signal including a right-eye image and a left-eye image is input to the liquid crystal display panel 20 as a video signal. Then, the right-eye image light L2 is output from the odd-numbered pixels (FIGS. 6A and 6B or FIGS. 7A and 7B), and the left-eye image light L3 is output from the even-numbered pixels. (FIG. 8 (A), (B) or FIG. 9 (A), (B)). Actually, the right-eye image light L2 and the left-eye image light L3 are output in a mixed state, but in FIGS. 6 to 9, for the convenience of explanation, the right-eye image light L2 and the left-eye image light L3 are output. Were described separately.

  Thereafter, the right-eye image light L2 and the left-eye image light L3 are converted into elliptically polarized light by the right-eye region 32A and the left-eye region 32B of the phase difference element 30, and after passing through the base film 31 of the phase difference element 30, The image is output from the image display surface of the display device 1 to the outside. At this time, both the light passing through the right eye region 32 </ b> A and the light passing through the left eye region 32 </ b> B are affected by slight optical anisotropy existing in the base film 31.

  Thereafter, the light output to the outside of the display device 1 enters the polarizing glasses 2, and is returned from elliptically polarized light to linearly polarized light by the right-eye phase difference film 41 </ b> B and the left-eye phase difference film 42 </ b> B. The light enters the polarizing plates 41A and 42A.

  At this time, the polarization axis of the light corresponding to the right-eye image light L2 among the incident light to the polarization plates 41A and 42A is parallel to the polarization axis AX7 of the polarization plate 41A, and the polarization axis AX8 of the polarization plate 42A. Orthogonal. Therefore, the light corresponding to the right-eye image light L2 among the incident light to the polarizing plates 41A and 42A passes through only the polarizing plate 41A and reaches the right eye of the observer (FIGS. 6A and 6B). Or FIG. 7 (A), (B)).

  On the other hand, the polarization axis of the light corresponding to the left-eye image light L3 out of the incident light to the polarizing plates 41A and 42A is orthogonal to the polarizing axis AX7 of the polarizing plate 41A and parallel to the polarizing axis AX8 of the polarizing plate 42A. It has become. Therefore, the light corresponding to the image light L3 for the left eye among the incident light to the polarizing plates 41A and 42A is transmitted only through the polarizing plate 42A and reaches the left eye of the observer (FIGS. 8A and 8B). Or FIG. 9 (A), (B)).

  In this way, as a result of the light corresponding to the right eye image light L2 reaching the right eye of the observer and the light corresponding to the left eye image light L3 reaching the left eye of the observer, the observer can view the image of the display device 1. It can be recognized as if a stereoscopic image is displayed on the display surface.

[effect]
By the way, in this Embodiment, the base film 31 of the phase difference element 30 is comprised with the thin resin film which has optical anisotropy. Therefore, as described above, both the light that has passed through the right eye region 32 </ b> A and the light that has passed through the left eye region 32 </ b> B are affected by slight optical anisotropy existing in the base film 31. Therefore, there is a possibility that ghost is included in the image light for the right eye and the image light for the left eye that have reached the eyes of the observer. Further, there is a possibility that the image light for the right eye and the image light for the left eye that have reached the eyes of the observer have a different hue from the original color.

  However, in the present embodiment, the slow axis AX3 of the base film 31 faces the horizontal direction or the vertical direction, and faces the direction intersecting with the slow axes AX1 and AX2. Therefore, the influence due to the optical anisotropy of the base film 31 affects each light transmitted through the base film 31, and the light corresponding to the right eye and the light corresponding to the left eye transmitted through the base film 31. It does not extend to one of the lights. As a result, it is possible to reduce unbalances such as, for example, a ghost appears strong only to the left eye or the right eye, or the video colors differ between the left eye and the right eye. Therefore, the phase difference element 30 and the display device 1 that are unlikely to cause imbalance can be realized.

  In particular, in the present embodiment, when the slow axis AX3 of the base film 31 is oriented in a direction parallel to the bisector of the slow axis AX1 and the slow axis AX2, The influence due to the optical anisotropy extends equally to each light transmitted through the base film 31. As a result, it is possible to eliminate imbalances such as, for example, a ghost looks strong only in the left eye or the right eye, or the colors of the images differ between the left eye and the right eye. Therefore, in this case, the phase difference element 30 and the display device 1 that do not cause imbalance can be realized.

  In the present embodiment, since a thin base film (resin film) is used as a base for supporting the retardation layer 32 of the retardation element 30, a glass plate is used as the support base for the retardation layer 32. The phase difference element 30 can be manufactured at a lower cost than in the case of using the above. Further, by using a base film (resin film) as the support base of the retardation layer 32, the display device 1 can be thinned.

[Modification]
In the above embodiment, the phase difference element 30 is provided with two types of phase difference regions (right eye region 32A and left eye region 32B) having different slow axis directions. There may be provided three or more kinds of phase difference regions different from each other. For example, as shown in FIG. 10, in addition to the right-eye region 32A and the left-eye region 32B, the phase difference element 30 has directions of the slow axes AX1 and AX2 of the right-eye region 32A and the left-eye region 32B. It is also possible to newly provide a third region 32C having a slow axis in a different direction.

  In the above embodiment, the case where the phase difference regions (the right eye region 32A and the left eye region 32B) of the phase difference element 30 extend in the horizontal direction is illustrated, but the phase difference regions 30 extend in other directions. It does not matter if it exists. For example, as shown in FIG. 11, the phase difference regions (the right eye region 32 </ b> A and the left eye region 32 </ b> B) of the phase difference element 30 may extend in the vertical direction.

  In the embodiment and the modification described above, the phase difference regions (the right eye region 32A and the left eye region 32B) of the phase difference element 30 extend over the entire horizontal or vertical direction of the phase difference element 30. Although the case has been illustrated, for example, as shown in FIG. 12, it may be two-dimensionally arranged both in the horizontal direction and in the vertical direction.

  Moreover, although the case where the phase difference element 30 was applied to the display apparatus 1 was illustrated in the said embodiment and each modification, of course, it is also possible to apply to another device.

  Further, in the above-described embodiment and each modification, there is no particular device for controlling the divergence angle of the light output from the liquid crystal display panel 20, but for example, as shown in FIG. 13, the liquid crystal display panel 20 A black stripe layer 40 may be provided between the first and second retardation elements 30. The black stripe layer 40 includes a transmissive portion 40A provided in a region facing the pixel electrode 23 in the liquid crystal display panel 20, and a light shielding portion 40B provided around the transmissive portion 40A. Thereby, when the observer observes the image display surface from the diagonally upper side or the diagonally lower side, the light that has passed through the left-eye pixel enters the right-eye region 32A, or the light that has passed through the right-eye pixel has left-eye region 32B. The problem called crosstalk that goes in can be solved.

  It is not always necessary to provide the black stripe layer 40 between the liquid crystal display panel 20 and the retardation element 30. For example, as shown in FIG. 14, the polarizing plate 21B and the transparent substrate 29 in the liquid crystal display panel 20 are provided. It is also possible to provide between.

  In the above description, the case where the polarizing glasses 2 are of the circularly polarized type and the display device 1 is a display device for circularly polarized glasses has been described. However, the polarizing glasses 2 are of the linearly polarized type and the display device 1 is linearly polarized. The present invention can also be applied to a display device for glasses.

[Example]
Hereinafter, Examples 1 and 2 of the display device 1 of the present embodiment will be described in comparison with Comparative Examples 1 and 2.

  Example 1 in which the slow axis AX3 of the base film 31 is oriented in the direction perpendicular to the boundary line L1 is taken as Example 1, and the slow axis AX3 of the base film 31 is oriented in the direction horizontal to the boundary line L1 Example 2 was adopted. That is, in Examples 1 and 2, the slow axis AX3 intersects with the slow axes AX1 and AX2, and the direction of the bisector of the slow axes AX1 and AX2 is set to be approximately the same. On the other hand, the slow axis AX3 of the base film 31 is set in the same direction as the slow axis AX2 of the left region 32B as Comparative Example 1, and the slow axis AX3 of the base film 31 is the slow phase of the right region 32A. A comparative example 2 was formed in the same direction as the axis AX1.

  First, the extinction ratio was measured and evaluated for Examples 1 and 2 and Comparative Examples 1 and 2. The extinction ratio is obtained by the following calculation formulas (1) and (2), and the extent to which ghost is generated can be quantitatively obtained.

  Since the transmission axis AX4 of the polarizing plate 21B on the light emission side of the display device 1 and the transmission axes AX7 and AX8 of the right eyeglass 41 and the left eyeglass 42 are preferably arranged in a crossed Nicol arrangement, The transmission axis AX4 of the polarizing plate 21B was the vertical direction, and the transmission axes AX7 and AX8 were the horizontal direction. In addition, the retardation of the right-eye region 32A and the left-eye region 32B of the retardation layer 32 is approximately λ / 4. The slow axis AX2 of the left eye region 32B and the slow axis AX6 of the left eye glasses 42 have the same orientation, and the slow axis AX1 of the right eye region 32A and the slow axis AX5 of the right eye glasses 41 have the same orientation. In such an arrangement, the extinction ratio of the right-eye region 32A and the left-eye region 32B was calculated using the extended Jones matrix method.

  The retardation of the retardation films 41A and 42B and the right-eye region 32A and the left-eye region 32B of the polarizing glasses 2 is preferably λ / 4 at all wavelengths. However, in the materials currently used for commercial use, Chromatic dispersion occurs. Here, polycarbonate is assumed as the retardation films 41A and 42B of the polarizing glasses 2, and a liquid crystal polymer is assumed as the material of the right eye region 32A and the left eye region 32B.

  The retardation films 41B and 42B of the polarizing glasses 2 have the same retardation values for the right eye and the left eye, and the retardation values shown in FIG. In addition, the retardation values for the right-eye region 32A and the left-eye region 32B are the same, and the retardation values shown in FIG. The substrate film 31 of the retardation element 30 is preferably isotropic with a retardation of 0, but has a slight retardation as long as it is an actual commercial film. Here, a ZEONOR (trademark of Nippon Zeon Co., Ltd.) film having a thickness of 100 μm is assumed as the base film 31, and the retardation value shown in FIG. That is, the retardation of the base film 31 was about 6 nm in the visible region.

  The calculation result of the extinction ratio is shown in FIG. In Comparative Example 1, the extinction ratio of the left-eye region 32B is low. This means that the image of the left-eye pixel is not only in the left eye but also in the right eye, and a ghost is generated in the right eye image. In Comparative Example 2, the extinction ratio of the right eye region 32A was low. This means that the image of the pixel for the right eye is not only in the right eye but also in the left eye, and a ghost is generated in the left eye. Therefore, in the case of Comparative Example 1 and Comparative Example 2, a strong ghost is generated only in one eye, making it difficult to observe a stereoscopic image. On the other hand, in Example 1 and Example 2, both eyes have the same extinction ratio, and a strong ghost does not occur only in one eye. Therefore, it is easy to observe a stereoscopic image, which is preferable.

  Subsequently, chromaticity was measured and evaluated for Examples 1 and 2 and Comparative Examples 1 and 2. The wavelength distribution when the polarizing glasses 2 are not used is shown in FIG. In this case, the chromaticity is u ′ = 0.1947 and v ′ = 0.39060 in the CIE (International Lighting Commission) L * u * v * color system. On the other hand, the chromaticities of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in FIG. From this figure, in the comparative example 1 and the comparative example 2, the left and right eyes have different color appearances, whereas in the first and second examples, the left eye and the right eye have the same chromaticity and the difference in color. I found that there was no.

  DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 2 ... Polarized glasses, 10 ... Backlight unit, 20 ... Liquid crystal display panel, 21A, 21B, 41A, 42A ... Polarizing plate, 22, 29 ... Transparent substrate, 23 ... Pixel electrode, 24, 26 ... Orientation Membrane, 25 ... Liquid crystal layer, 27 ... Common electrode, 28 ... Color filter, 28A ... Filter portion, 28B ... Black matrix portion, 30 ... Phase difference element, 31 ... Substrate film, 32 ... Phase difference layer, 32A ... For right eye Area, 32B ... Left eye area, 40 ... Black stripe part, 40A ... Transmission part, 40B ... Light-shielding part, 41 ... Right eyeglass, 41B ... Right eye retardation film, 42 ... Left eyeglass, 42B ... Left eye retardation the film.

Claims (3)

A display panel driven based on an image signal;
A backlight unit for illuminating the display panel;
A retardation element provided on the opposite side of the backlight unit in relation to the display panel,
The phase difference element is
A base film having optical anisotropy;
A retardation layer formed on the display panel side surface of the base film and having optical anisotropy;
The retardation layer has two types of retardation regions with different slow axis directions,
The two types of retardation regions are regularly arranged adjacent to each other in the in-plane direction of the base film,
Each of the phase difference regions has a slow axis in a direction intersecting with a boundary line between adjacent phase difference regions at an angle other than orthogonal,
The base film has a slow axis in a direction parallel to or perpendicular to the boundary line,
Of the two types of phase difference regions, the slow axis of one type of phase difference region is defined as a first slow axis, and the slow axis of the other type of phase difference region of the two types of phase difference regions is defined as a first slow axis. In the case of two slow axes, the bisector of the first slow axis and the second slow axis and the slow axis of the base film are parallel to each other,
Each of the two types of retardation regions has a retardation of λ / 4. The display device according to claim 1, wherein the base film is made of a resin film. The display device according to claim 1, wherein directions of slow axes of the two types of phase difference regions are different by 90 °.

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