JP2020076947A - Image display device, image display member, and optical member - Google Patents

Abstract

To sufficiently ensure contrast of a display screen even when viewing angle characteristics are improved compared to a prior art and a display screen is visually recognized from an oblique direction.SOLUTION: An image display device 1 has a liquid crystal layer 8 provided between a substrate 7 and a substrate 12, a linearly polarizing plate 6 arranged on the substrate 7 on the opposite side of the liquid crystal layer 8, and a linearly polarizing plate 24 arranged on the substrate 12 on the opposite side of the liquid crystal layer 8 such that a transmission axis is orthogonal to the linearly polarizing plate 6. A 1/4 wavelength phase difference layer 9 in which its slow axis forms an angle of 45 degrees with respect to the transmission axis of the linearly polarizing plate 6 is provided between the liquid crystal layer 8 and the substrate 12, and a 1/4 wavelength phase difference layer 21 in which its slow axis is orthogonal to the slow axis of the 1/4 wavelength phase difference layer 9 is provided between the substrate 12 and the linearly polarizing plate 24. A positive C plate 10 is provided between the 1/4 wavelength phase difference layer 9 and the 1/4 wavelength phase difference layer 21, and a compensation layer 22 including a phase difference layer having an NZ value of 0.10 or more and 0.90 or less is provided between the linearly polarizing plate 24 and the 1/4 wavelength phase difference layer 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device in which an antireflection film is arranged on a panel surface of a liquid crystal display panel, an image display member and an optical member related to the image display device.

Conventionally, a method of arranging an antireflection film by laminating a linear polarizing plate and a quarter-wave retardation layer on the panel surface (viewer side surface) of an image display panel and reducing reflection of extraneous light by this antireflection film has been proposed. Proposed. In this antireflection film, external light traveling toward the panel surface of the image display panel is converted into linearly polarized light by the linearly polarizing plate, and then converted into circularly polarized light by the ¼ wavelength retardation layer. The extraneous light due to the circularly polarized light is reflected on the surface of the image display panel or the like, but the direction of rotation of the polarization plane is reversed during this reflection. As a result, this reflected light is converted into linearly polarized light in the direction in which it is shielded by the linearly polarizing plate by the ¼ wavelength phase difference layer, and then is shielded by the following linearly polarizing plate. As a result, the emission to the outside is significantly suppressed.
Conventionally, various ideas have been proposed for such an antireflection film (for example, Patent Document 1).

International Publication No. 2017/179493

  By the way, when an image display device using a liquid crystal display panel in which an antireflection film of this kind is arranged is viewed from an oblique direction, the contrast at the time of black display (so-called black contrast However, it has been desired to further improve the viewing angle characteristics.

  The present invention has been made in view of such circumstances, and it is possible to improve the viewing angle characteristics as compared with the related art and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction. ,With the goal.

  The present inventor has conducted extensive studies in order to solve the above problems, and has come to the idea that the optical characteristics are compensated by a compensation layer having a retardation layer having a constant NZ value, and the present invention is completed. I arrived.

  Specifically, the present invention provides the following.

(1) A liquid crystal layer is provided between the first substrate and the second substrate held so as to face each other,
On the opposite side of the first substrate from the liquid crystal layer, a first linear polarizing plate that emits linearly polarized light incident from a backlight is arranged.
A second linear polarizing plate is disposed on the side of the second substrate opposite to the liquid crystal layer so that the transmission axis is orthogonal to the first linear polarizing plate.
A first quarter-wave retardation layer whose slow axis forms an angle of 45 degrees with the transmission axis of the first linear polarizing plate is provided between the liquid crystal layer and the second substrate. ,
A second quarter-wave retardation layer in which a slow axis and a slow axis of the first quarter-wave retardation layer are orthogonal to each other between the second substrate and the second linear polarizing plate. Is provided,
A positive C plate is provided between the first quarter-wave retardation layer and the second quarter-wave retardation layer,
A compensation layer including a retardation layer having an NZ value of 0.10 or more and 0.90 or less is provided between the second linear polarizing plate and the second ¼ wavelength retardation layer,
An angle formed by the slow axis of the second quarter-wave retardation layer and the slow axis of the retardation layer is 45 degrees.

  According to (1), the polarization state is changed by the compensation layer, the viewing angle characteristics are improved, and the contrast of the display screen can be sufficiently secured even when the display screen is viewed from an oblique direction.

(2) In (1),
The retardation layer of the compensation layer,
The slow axis is arranged so as to be orthogonal to the transmission axis of the first linear polarizing plate.

  According to the configuration of (2), with a more specific configuration, the viewing angle characteristics can be improved, and the contrast of the display screen can be sufficiently secured even when the display screen is viewed from an oblique direction.

(3) In (1),
The retardation layer of the compensation layer,
The slow axis is arranged so as to be parallel to the transmission axis of the first linear polarizing plate.

  According to the configuration of (3), with a more specific configuration, it is possible to improve the viewing angle characteristics and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(4) In any of (1) to (3),
The compensation layer is
A negative A plate is arranged on the side of the second linear polarizing plate of the retardation layer or on the opposite side thereof so that the slow axis is orthogonal to the transmission axis of the first linear polarizing plate.

  According to (4), it is possible to more surely improve the viewing angle characteristics as compared with the related art, and to sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(5) In any one of (1) to (3),
The compensation layer is
A positive C plate is provided on the side of or opposite to the second linearly polarizing plate of the retardation layer.

  According to (5), it is possible to more surely improve the viewing angle characteristics as compared with the related art and to sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(6) In any of (1) to (3),
The compensation layer is
On the side of the second linear polarizing plate of the retardation layer, there is a positive A plate arranged so that the slow axis is parallel to the transmission axis of the first linear polarizing plate.

  According to (6), it is possible to more surely improve the viewing angle characteristics as compared with the related art, and to sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(7) In any of (1) to (3),
The compensation layer has a negative C plate on the second linear polarizing plate side of the retardation layer.

  According to (7), it is possible to more surely improve the viewing angle characteristics as compared with the related art, and to sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(8) In any one of (1) to (7),
The liquid crystal layer is a liquid crystal layer in a lateral electric field mode,
A transparent electrode according to the lateral electric field mode is formed on the first substrate.

(9) In any one of the configurations (1) to (8),
A color filter is provided on the second substrate.

(10) In any one of the configurations (1) to (9),
Furthermore, the touch panel sensor film is provided.

(11) In (1),
The retardation layer has a slow axis parallel to the transmission axis of the first linear polarizing plate and an NZ value of 0.50 or more and 0.85 or less.

  According to (11), it is possible to improve the viewing angle characteristics as compared with the related art and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(12) In (1),
The retardation layer has a slow axis orthogonal to the transmission axis of the first linear polarizing plate and an NZ value of 0.1 or more and 0.5 or less.

  According to (12), the viewing angle characteristics can be improved as compared with the related art, and the contrast of the display screen can be sufficiently ensured even when the display screen is viewed from an oblique direction.

(13) A first quarter-wave retardation layer is provided on one surface side of the substrate,
On the other surface side of the substrate, a second quarter-wave retardation layer having a slow axis orthogonal to the slow axis of the first quarter-wave retardation layer, and an NZ value of 0.10. And a compensating layer having a retardation layer of 0.90 or less,
The angle formed by the slow axis of the second quarter-wave retardation layer and the slow axis of the retardation layer is 45 degrees,
An image display member in which a positive C plate is provided between the first quarter-wave retardation layer and the second quarter-wave retardation layer.

  According to (13), the polarization state of the light emitted from the second ¼ wavelength phase layer can be brought closer to the polarization state of the light incident on the first ¼ wavelength phase difference from the oblique direction, and the liquid crystal It is possible to suppress a decrease in contrast in the image display device using the display panel.

(14) In (13),
The compensation layer comprises a negative A plate,
The angle formed by the slow axis of the negative A plate and the slow axis of the second quarter-wave retardation layer is 45 degrees.

  According to (14), with a more specific configuration, the viewing angle characteristics can be improved, and the contrast of the display screen can be sufficiently secured even when the display screen is viewed from an oblique direction.

(15) In (13),
The compensation layer comprises a positive C plate.

(16) In (13),
The compensation layer comprises a positive A plate,
The retardation layer is provided between the positive A plate and the second quarter-wave retardation layer,
The slow axis of the positive A plate and the slow axis of the second quarter-wave retardation layer form an angle of 45 degrees.

  According to (15) or (16), with a more specific configuration, it is possible to improve the viewing angle characteristics and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(17) In (13),
The compensation layer comprises a negative C plate,
The retardation layer is provided between the negative C plate and the second quarter-wave retardation layer.

(18) A compensation layer having a retardation layer having an NZ value of 0.10 or more and 0.90 or less is provided between the linear polarizing plate and the ¼ wavelength retardation layer,
The transmission axis of the linear polarizing plate and the slow axis of the ¼ wavelength retardation layer form an angle of 45 degrees,
An optical member in which the transmission axis of the linearly polarizing plate and the slow axis of the retardation layer are parallel or orthogonal to each other.

  According to (17) or (18), the polarization state is changed by the compensation layer, the viewing angle characteristics are improved, and the contrast of the display screen is sufficiently secured even when the display screen is viewed from an oblique direction. You can

(19) In (18),
The compensation layer comprises a negative A plate,
The slow axis of the negative A plate and the transmission axis of the linear polarizing plate are parallel to each other.

(20) In (18),
The compensation layer comprises a positive C plate.

  According to (19) or (20), with a more specific configuration, it is possible to improve the viewing angle characteristics and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

(21) In (18),
The compensation layer comprises a positive A plate,
The phase difference layer is provided between the positive A plate and the quarter wavelength phase difference layer,
The slow axis of the positive A plate and the transmission axis of the linear polarizing plate are orthogonal to each other.

(22) In (18),
The compensation layer comprises a negative C plate,
The retardation layer is provided between the negative C plate and the quarter-wave retardation layer.

  According to (21) or (22), with a more specific configuration, it is possible to improve the viewing angle characteristics and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

  According to the present invention, it is possible to improve the viewing angle characteristics as compared with the related art and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

It is a sectional view showing an image display device concerning a 1st embodiment of the present invention. FIG. 3 is a diagram illustrating a change in polarization state when a compensation layer is not provided in the image display device of FIG. 1. It is a figure explaining an observation direction. It is a figure explaining the example which changed the observation direction. It is a figure explaining the change of the polarization state by the observation direction of FIG. It is a figure explaining the change of the polarization state in case an NZ value is 0.35. It is a figure explaining the change of the polarization state in case an NZ value is 0.5. 7 is a contour diagram showing characteristics of the image display devices of Comparative Example 1 and Comparative Example 2. FIG. FIG. 7 is a contour diagram showing characteristics of the image display device when the NZ value of the compensation layer is changed. FIG. 7 is a contour diagram showing characteristics of the image display device when the NZ value of the compensation layer is changed. FIG. 7 is a contour diagram showing characteristics of the image display device when the NZ value of the compensation layer is changed. FIG. 7 is a contour diagram showing characteristics of the image display device when the NZ value of the compensation layer is changed. FIG. 7 is a contour diagram showing characteristics of the image display device when the NZ value of the compensation layer is changed. FIG. 7 is a contour diagram showing characteristics of the image display device when the NZ value of the compensation layer is changed. It is sectional drawing which shows the image display apparatus which concerns on 2nd Embodiment of this invention. It is a figure explaining the image display apparatus of 2nd Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 2nd embodiment of the present invention. It is a figure explaining the image display apparatus of 3rd Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 3rd embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 4th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 4th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 5th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 5th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 6th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 6th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 7th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 7th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 8th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of an 8th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 9th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 9th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 10th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 10th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 11th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of an 11th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 12th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 12th embodiment of the present invention. It is a figure explaining the image display apparatus which concerns on 13th Embodiment of this invention. It is a contour diagram showing the characteristic of the image display device of a 13th embodiment of the present invention. It is a chart which summarized the composition of each embodiment of the present invention. FIG. 41 is a chart continued from FIG. 40.

[First Embodiment]
[Image display device]
FIG. 1 is a sectional view showing an image display device according to the first embodiment of the present invention.
In this image display device 1, an antireflection film 3 which is an optical member is attached and held on a panel surface (viewer side surface) of an image display panel 2 by a pressure sensitive adhesive or the like, and the antireflection film 3 serves as an outside An antireflection portion that prevents reflection of light is formed.
The image display panel 2 is a liquid crystal display panel and is formed by disposing the backlight 4 on the back surface of the liquid crystal cell 5.
Thereby, the image display device 1 spatially modulates the light emitted from the backlight 4 to display a desired image. Further, images are displayed in this manner, and the antireflection film 3 prevents reflection of external light.

  Here, as the backlight 4, backlights of various configurations such as so-called edge light type and direct type can be widely applied.

[Liquid crystal cell]
The liquid crystal cell 5 is a liquid crystal cell based on an IPS (In-Plane-Switching) method, which is a liquid crystal cell in a so-called horizontal electric field mode, and includes a drive circuit such as a TFT (Thin Film Transistor) and a transparent electrode for generating a horizontal electric field. The linear polarizing plate 6 is provided on the side of the backlight 4 of the first substrate 7 that is created, and the second side of the first substrate 7 opposite to the backlight 4 is provided so as to face the first substrate 7. A substrate 12 is provided.
The second substrate 12 is provided with a color filter 11 on the backlight 4 side, and the liquid crystal cell 5 includes a liquid crystal layer 8 and a quarter wavelength phase difference between the substrates 7 and 12 sequentially from the backlight 4 side. A layer 9, a positive C-plate 10, is arranged.

  As a result, the liquid crystal cell 5 converts the light emitted from the backlight 4 into linearly polarized light by the linearly polarizing plate 6 and makes it enter the liquid crystal layer 8 to impart a phase difference. The emitted light of the liquid crystal layer 8 is sequentially emitted through the quarter-wave retardation layer 9 and the positive C plate 10. In the image display device 1, the emitted light of the liquid crystal cell 5 is emitted through the linear polarizing plate 24 provided on the antireflection film 3 so that the emitted light of the liquid crystal cell 5 becomes the phase difference imparted by the liquid crystal layer 8. The light is emitted with a corresponding light intensity, whereby the light emitted from the backlight 4 is spatially modulated to display a desired image.

Here, the linear polarizing plate 6 is the first linear polarizing plate in the image display device 1 and is arranged so that the transmission axis direction is orthogonal to the linear polarizing plate 24 provided in the antireflection film 3. The linear polarizing plate 6 can be formed by, for example, dyeing and adsorbing an anisotropic material such as an iodine complex (or dye) on a polyvinyl alcohol (PVA) film, and then stretching and orienting the dye.
As the substrates 7 and 12, for example, a glass substrate, a plastic substrate or the like can be applied.

The quarter-wave retardation layer 9 is the first quarter-wave retardation layer in the image display device 1 and is configured to give a quarter-wave retardation to the transmitted light, and is an antireflection film. It is provided in order to cancel the retardation imparted to the transmitted light by the quarter-wave retardation layer 21 provided in 3. Therefore, the quarter-wave retardation layer 9 is arranged so that the slow-axis direction is orthogonal to the quarter-wave retardation layer 21 provided on the antireflection film 3.
The quarter-wave retardation layer 9 is a quarter-wave retardation layer having a main refractive index satisfying the relationship of nx> ny ≧ nz, and has an in-plane slow axis with respect to the transmission axis direction of the linear polarizing plate 6. It is arranged to form an angle of 45 °. The quarter-wave retardation layer 9 is a uniaxial quarter-wave retardation layer (positive A plate) having a main refractive index satisfying a relationship of nx> ny = nz, and a main refractive index of nx>ny> nz. A biaxial quarter-wave retardation layer satisfying the relationship can be applied.
Here, nx is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), and ny is the direction in the plane that is orthogonal to the slow axis (that is, the fast axis direction). And nz is the refractive index in the thickness direction.

The positive C plate 10 is provided to improve the viewing angle characteristics. The positive C plate 10 is a uniaxial positive C plate having a main refractive index satisfying the relationship of nx = ny <nz, but has a biaxial phase difference satisfying the main refractive index of ny <nx <nz. Plates may be applied.
The positive C plate 10 may be arranged closer to the antireflection film 3 side than the color filter 11, for example, may be provided on the antireflection film 3 side of the substrate 12, and in this case, the antireflection film. It may be configured so as to be integrated with 3.
Further, the liquid crystal cell 5 is not limited to the IPS system, and a wide variety of liquid crystal cell structures based on a so-called lateral electric field mode such as an FFS (Fringe Field Switching) system and various other structures can be widely applied.

  For the quarter-wave retardation layer 9 and the positive C plate 10, a stretched polymer film, an oriented, cured liquid crystal material or the like can be applied.

[Anti-reflection film]
The antireflection film 3 is formed by sequentially laminating a linear polarizing plate 24, a compensation layer 22, and a 1/4 wavelength retardation layer 21, and is arranged so that the 1/4 wavelength retardation layer 21 is on the image display panel 2 side. To be done.
As a result, the antireflection film 3 converts external light into linearly polarized light by the linearly polarizing plate 24, then transmits through the compensation layer 22 and enters the ¼ wavelength retardation layer 21, and is circularly polarized to the image display panel 2. Emit. Further, as a result, the incident light from the image display panel 2, which is reflected by the image display panel 2 and the rotation direction of the polarization plane is reversed, is converted into linearly polarized light by the ¼ wavelength phase difference layer 21, and then the compensation layer 22. Is transmitted through and is blocked by the linear polarizing plate 24.

Therefore, in the antireflection film 3, the quarter-wave retardation layer 21 is a quarter-wave retardation layer whose main refractive index satisfies the relationship of nx> ny ≧ nz, and is arranged in the transmission axis direction of the linear polarizing plate 24. On the other hand, the in-plane slow axis is arranged so as to form an angle of 45 °. The quarter-wave retardation layer 21 is a uniaxial quarter-wave retardation layer (positive A plate) having a main refractive index satisfying the relationship of nx> ny = nz, and having a main refractive index of nx>ny> nz. A biaxial quarter-wave retardation layer satisfying the relationship can be applied.
The quarter-wave retardation layer 21 is the second quarter-wave retardation layer in the image display device 1 and can be configured similarly to the quarter-wave retardation layer 9.

  Further, in the antireflection film 3, the linear polarizing plate 24 is the second linear polarizing plate in the image display device 1 and can be configured in the same manner as the linear polarizing plate 6.

Here, in the image display device 1 of this type, the positive C plate 10 is arranged to improve the viewing angle characteristics and secure a sufficient contrast in a wide viewing angle.
However, when only the positive C plate 10 is used, sufficient contrast may not be ensured when the display screen is viewed from an oblique direction.
Therefore, in the antireflection film 3, the viewing angle characteristics are improved by the compensation layer 22.

  FIG. 2 is a diagram for explaining a polarization state when only the positive C plate 10 is arranged (when the compensation layer 22 is not provided), and FIG. 2A shows a change in polarization due to a Poincare sphere. FIG. 2B is a diagram showing a change in the polarization state on the Poincare sphere as viewed from the north pole direction.

Further, FIG. 3 is a schematic diagram showing an observation azimuth relating to the examination of the polarization state according to FIG. In FIG. 3, the transmission axis direction of the linear polarizing plate 6 and the slow axis direction of the quarter-wave retardation layers 9 and 21 are indicated by arrows, and the reference A indicates the observation direction.
In addition, in FIG. 3 and FIG. 4 described later, a configuration using a stretched film of polyvinyl alcohol (film thickness 20.00 μm) is applied to the linear polarizing plates 6 and 24, and the ¼ wavelength phase difference layers 9 and 21 are The cycloolefin polymer resin was formed to a thickness of 56.12 μm (Re = 137.50 nm, NZ = 1.0). The positive C plate 10 was formed of a polymerizable liquid crystal material with a thickness of 0.63 μm (Rth = −108.24 nm).

  Here, in the arrangement of FIG. 3, the in-plane slow axes of the quarter-wave retardation layers 9 and 21 with respect to the observation direction A are set to angles of 45 degrees and 135 degrees, respectively. When viewed from an oblique direction by A, the 1/4 wavelength retardation layer 9 has an in-plane slow axis of an angle smaller than 45 degrees with respect to the observation direction A, and the 1/4 wavelength retardation layer 21 has It seems that the in-plane slow axis forms an angle larger than 135 degrees with respect to the observation direction A. As a result, assuming that the amounts of displacement from 45 degrees and 135 degrees are α, the quarter-wave retardation layer 9 for the transmitted light in the oblique direction due to the observation azimuth A has an in-plane slow axis with respect to the observation azimuth A. Is 45-α degrees, and the 1/4 wavelength retardation layer 21 has an in-plane slow axis of 135 degrees + α degrees with respect to the observation direction A.

The incident polarized light emitted from the backlight 4 and transmitted through the linear polarizing plate 6, the substrate 7 and the liquid crystal layer 8 (when no electric field is applied) is originally the linear polarized light shielded by the linear polarizing plate 24 (see FIG. 2 and FIG. 3), by passing through the quarter-wave retardation layer 9, as indicated by an arrow B, by the rotation axis L1 (45 degrees-α) around the in-plane slow axis of the quarter-wave retardation layer 9 The polarization state changes to the rotated position. Further, as indicated by an arrow C, the positive C plate 10 changes the polarization state to a position rotated about the x axis as a rotation axis, and the subsequent ¼ wavelength retardation layer 21 causes a 1 C The quarter-wave retardation layer 21 is rotated around the rotation axis L2 (135 degrees + α) by the in-plane slow axis to return to the polarization state of the incident polarized light.
Here, the polarization state of this incident polarized light is linear polarized light that matches the extinction position (direction of the absorption axis) of the linear polarizing plate 24 provided on the antireflection film 3.
Accordingly, in this case, when only the positive C plate is arranged to constitute the antireflection film, the light emitted from the backlight 4 can be surely blocked and the dark place contrast can be secured. Further, this makes it possible to prevent reflection of external light that is obliquely incident, and also to secure dark place contrast.

FIG. 4 is a diagram for explaining an example in which the observation directions are different, and is a diagram corresponding to FIG.
FIG. 5 is a diagram for explaining changes in the polarization state depending on the viewing direction of FIG. 4, and is a diagram corresponding to FIG. 2.
On the other hand, as shown in FIG. 4 in comparison with FIG. 3, the observation direction is changed by 45 degrees for consideration. When the observation azimuth is changed by 45 degrees, as shown in FIG. 4, the transmission axis of the linear polarizing plate 6 is 45 degrees with respect to the observation azimuth A, and the slow axis of the quarter-wave retardation layer 9 is observed. The azimuth A is 90 degrees, and the slow axis of the quarter-wave retardation layer 21 is 0 degrees with respect to the observation azimuth A.
In the example of FIG. 5, the in-plane slow axes of the quarter-wave retardation layers 9 and 21 with respect to the observation azimuth A are set at angles of 90 degrees and 0 degrees. In the transmitted light in the oblique direction, the slow axis of the quarter-wave retardation layer 9 forms 90 degrees with respect to the observation direction A, and the slow axis of the quarter-wave retardation layer 21 is The angle is 0 degree with respect to the observation direction A.
Further, as shown in FIG. 5 by comparison with FIG. 2, in the emitted light emitted obliquely to this observation direction, the position of an angle of 45 ° −α on the equator becomes the incident polarized light.

As shown by arrow B, this incident polarized light changes its polarization state with the rotation axis (x axis) by the in-plane slow axis of the quarter-wave retardation layer 9 as the rotation axis, and as shown by arrow C. Then, after changing with the positive C plate 10 with the x-axis as the rotation axis, the in-plane retardation of the quarter-wave retardation layer 21 is continued by the subsequent quarter-wave retardation layer 21 as indicated by an arrow D. The polarization state changes with the axis of rotation (x axis) as the axis of rotation, and the light is emitted as elliptically polarized light.
As a result, when only this positive C plate is arranged (when the compensation layer 22 is not provided), the outgoing light cannot be blocked sufficiently by the linear polarizing plate 24, and the dark place contrast is lowered.

  Therefore, in the antireflection film 3, the polarization state of the transmitted light is changed by the compensation layer 22 to improve the viewing angle characteristics as compared with the conventional case, and the contrast of the display screen is sufficiently improved even when the display screen is viewed from an oblique direction. To be able to secure.

Here, the compensation layer 22 is a retardation layer having an NZ value in a predetermined range in this embodiment, and is formed of a retardation layer having biaxial optical anisotropy.
The NZ value is defined by NZ = (nz-nx) / (ny-nx).
Accordingly, in this embodiment, the rotation axis is set by selecting the NZ value of the retardation layer, and the polarization state of the incident polarized light indicated by the reference symbol P1 is changed to the incident polarized light as indicated by the arrow X in FIG. It is possible to change the polarization state so that it is located on the equator that is symmetrical about the y-axis with respect to the position of 1. Even in this case, the contrast of the display screen can be sufficiently secured.

Here, as for the NZ value of the retardation layer related to the compensation layer 22, the viewing angle characteristic can be improved as compared with the conventional one because the NZ value is 0.10 or more and 0.90 or less. However, when the in-plane slow axis of the retardation layer of the compensating layer 22 is arranged so as to be orthogonal to the transmission axis of the first linear polarizing plate 6 (the slow phase of the retardation layer of the compensating layer 22). When the angle between the axis and the slow axis of the second quarter-wave retardation layer 21 is 45 degrees), the NZ value is set to 0.10 or more and 0.90 or less, and Although the viewing angle characteristics can be sufficiently improved in comparison, when the compensation layer 22 is formed of only the retardation layer, the NZ value is set to 0.10 or more and 0.50 or less to further improve the viewing angle characteristics. Can be improved.
When the retardation layer of the compensation layer 22 is arranged such that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6 (the retardation layer of the compensation layer 22 is slow). When the angle formed by the phase axis and the slow axis of the second quarter-wave retardation layer 21 is 45 degrees), similarly, the NZ value should be 0.10 or more and 0.90 or less. Although the viewing angle characteristics can be sufficiently improved as compared with the conventional one, when the compensation layer 22 is formed of only the retardation layer, the NZ value is set to 0.50 or more and 0.85 or less, The viewing angle characteristics can be further improved.

  Here, the retardation layer related to the compensation layer 22 can be formed by biaxially stretching a transparent film material such as polycarbonate.

(When NZ = 0.35 of the compensation layer 22)
FIG. 6 is a diagram showing changes in the polarization state of the image display device according to this embodiment when the compensation layer 22 is formed of a retardation layer having an NZ value of 0.35, in comparison with FIG. FIG. 6 is a diagram showing a change in the polarization state by the compensation layer 22 from the polarization state of the emitted light emitted from the quarter-wave retardation layer 21 indicated by the reference symbol P1 in FIG.
The compensation layer 22 was arranged such that the slow axis formed an angle of 90 degrees in the transmission axis direction of the first linear polarizing plate 6.
The compensation layer 22 is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 70.00 μm (Re = 191.10 nm, Rth = −29.05). Re is the in-plane retardation, and Rth is the retardation in the thickness direction.

In the example of FIG. 6, when the rotation axis L2 of the compensation layer 22 is rotated as shown by the arrow, the rotation axis L2 is tilted from the y-axis and emitted from the quarter-wave retardation layer 21. The polarization state (P1) of the emitted light can be emitted by the emitted polarized light that is linearly polarized light corresponding to the incident polarized light on the equator.
As a result, in this example, the outgoing light can be emitted by almost ideal outgoing polarization, the viewing angle characteristics are improved compared to the conventional one, and the contrast of the display screen is improved even when the display screen is viewed from an oblique direction. Can be sufficiently secured.

(When NZ = 0.5 of the compensation layer 22)
On the other hand, FIG. 7 is a diagram showing a change in the polarization state in the case where the compensating layer 22 is composed of a retardation layer having an NZ value of 0.5 in comparison with FIG.
The compensation layer 22 was arranged such that the slow axis formed an angle of 90 degrees in the transmission axis direction of the first linear polarizing plate 6.
The compensation layer 22 was formed by applying a biaxially stretched polycarbonate film material and having a thickness of 75.00 μm (Re = 204.75 nm, Rth = 0.38).

  In the example of FIG. 7, as shown by the arrow, the polarization state can be changed to a position substantially close to the ideal position by rotating the rotation axis of the compensation layer 22. As a result, the viewing angle characteristics can be improved, and the contrast of the display screen can be sufficiently secured even when the display screen is viewed from an oblique direction.

Here, the contrast value of the display screen of each of the image display devices of Comparative Examples 1 and 2 and this embodiment was calculated.
Comparative Example 1 has a configuration in which the compensation layer 22 is omitted from the configuration of this embodiment.
Comparative Example 2 has a configuration in which a negative A plate is arranged instead of the compensation layer 22 in the configuration of this embodiment. The A plate is arranged so that the slow axis forms an angle of 90 degrees with the transmission axis of the linear polarizing plate 6, and the thickness is 1.22 μm (Re = 153.27 nm, Rth = −76.63 nm). Is.
When the contrast was calculated using oblique light having an emission angle of 60 degrees, in Comparative Example 1, the contrast value was 523 in the observation direction according to FIG. 3, but the contrast value was 17 in the observation direction according to FIG. there were.
Further, when calculated in the same manner, in Comparative Example 2, the contrast values of the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4 were 524 and 142, respectively.
Note that the contrast values and contour diagrams (described later) described in this description are the results of calculations simulated using LCD MASTER from SINTECH.

FIG. 8 is a contour diagram showing the characteristics of the image display device of each comparative example.
8 (A) and 8 (B) are contour diagrams of contrast values by simulation of the image display devices of Comparative Example 1 and Comparative Example 2, respectively, and FIG. 8 (C) is a contrast value of these contour diagrams. It is a figure which shows the value of the contour line of. In these contour diagrams, 0.0-180.0 degrees is the transmission axis direction of the linear polarizing plate 6.

9 to 14 are contour diagrams showing the characteristics of the image display device when the NZ value of the compensation layer is changed. 9 (A), (B) and FIGS. 10 (A), (B) are contour diagrams of the contrast value by the simulation of the image display device, and FIGS. 9 (C) and 10 (C) show these. It is a figure which shows the value of the contour line of the contrast value in the contour diagram of FIG. FIG. 11A is a contour diagram of contrast values by a simulation of the image display device, and FIG. 11B is a diagram showing contour line values of the contrast values in this contour diagram. 12 (A), (B) and 13 (A), (B) are contour diagrams of the contrast value by the simulation of the image display device, and FIGS. 12 (C) and 13 (C) show these. It is a figure which shows the value of the contour line of the contrast value in the contour diagram of FIG. FIG. 14A is a contour diagram of contrast values by a simulation of an image display device, and FIG. 14B is a diagram showing contour line values of the contrast values in this contour diagram.
In these contour diagrams, the center is the polar angle 0 degree direction (panel normal direction), and the concentric circles centering on this polar angle 0 degree are the polar angles 20 degrees, 40 degrees, 60 degrees, and 80 degrees from the center side, respectively. It is in the direction of degrees (the same applies to contour diagrams of the second and subsequent embodiments).
9 to 11 are contour diagrams of a configuration in which the slow axis of the compensation layer 22 is arranged in parallel with the transmission axis of the first linear polarizing plate 6 and the NZ value is changed. FIG. 14 is a contour diagram of a configuration in which the slow axis of the compensation layer 22 is arranged so as to be orthogonal to the transmission axis of the first linear polarizing plate 6 and the NZ value is changed.

  FIG. 9A is a contour diagram in which a retardation layer having an NZ value = 0.40 is applied to the compensation layer 22, and the contrast value of 523 is the same as that of the observation direction according to FIG. In the observation direction according to FIG. 4, the contrast value was 126.

  FIG. 9B is a contour diagram in which a retardation layer having an NZ value of 0.50 is applied to the compensation layer 22, and in the observation orientation according to FIG. 3, the contrast value of 524 is shown in FIG. In this observation direction, the contrast value was 267.

  FIG. 10A is a contour diagram in which a retardation layer having an NZ value = 0.65 is applied to the compensation layer 22, and in the observation orientation according to FIG. 3, the contrast value of 524 is shown in FIG. In this observation direction, the contrast value was 756.

  FIG. 10B is a contour diagram in which a retardation layer having an NZ value = 0.85 is applied to the compensation layer 22, and the contrast value of 524 in the observation orientation according to FIG. In this observation direction, the contrast value was 253.

  FIG. 11 is a contour diagram in which a retardation layer having an NZ value = 0.90 is applied to the compensation layer 22, and the observation orientation according to FIG. 3 has a contrast value of 524, but the observation orientation according to FIG. Then, the contrast value was 186.

  FIG. 12A is a contour diagram in which a retardation layer having an NZ value = 0.10 is applied to the compensation layer 22, and in the observation orientation according to FIG. 3, the contrast value of 523 is shown in FIG. In this observation direction, the contrast value was 218.

  FIG. 12B is a contour diagram in which a retardation layer having an NZ value = 0.20 is applied to the compensation layer 22, and in the viewing direction according to FIG. 3, the contrast value of 523 is shown in FIG. In this observation direction, the contrast value was 458.

  FIG. 13A is a contour diagram in which a retardation layer having an NZ value = 0.35 is applied to the compensation layer 22, and in the observation orientation according to FIG. 3, the contrast value of 524 is shown in FIG. In this observation direction, the contrast value was 1045.

  FIG. 13B is a contour diagram in which a retardation layer having an NZ value = 0.50 is applied to the compensation layer 22, and in the observation orientation according to FIG. 3, the contrast value of 524 is shown in FIG. In this observation direction, the contrast value was 279.

FIG. 14 is a contour diagram in which a retardation layer having an NZ value = 0.55 is applied to the compensation layer 22, and in the observation orientation according to FIG. 3, the contrast value of 524 is the observation orientation according to FIG. Then, the contrast value was 183.
The above-mentioned contrast values of the observation direction according to FIG. 3 represent the contrast values of 0 °, 180 °, and 60 ° of polar angle in the corresponding contour diagram, and the contrast values of the observation direction according to FIG. The contrast values are 45 degrees, 225 degrees, and a polar angle of 60 degrees in the contour diagram (the same applies to the contrast values of the second and subsequent embodiments).

As described above, it is confirmed from the results of FIGS. 9 to 14 described above that when the NZ value of the compensation layer 22 is 0.10 or more and 0.90 or less, it is possible to sufficiently secure the contrast of the display screen in the oblique direction. Was done.
Further, more preferably, if the contrast value in the viewing direction shown in FIG. 4 is 200 or more, it is possible to more sufficiently secure the contrast of the display screen in the oblique direction with respect to each comparative example. Specifically, the in-plane slow axis of the retardation layer relating to the compensation layer 22 is arranged so as to be parallel to the transmission axis of the first linear polarizing plate 6, and the compensation layer 22 is retarded. In the case of forming only by layers, the viewing angle characteristics can be further improved by setting the NZ value to 0.5 or more and 0.85 or less (FIG. 9 (B), FIG. 10 (A), FIG. 10 ( See B)).
Further, the in-plane slow axis of the retardation layer related to the compensation layer 22 is arranged so as to be orthogonal to the transmission axis of the first linear polarizing plate 6, and the compensation layer 22 is formed only by the retardation layer. When forming, the viewing angle characteristics can be further improved by setting the NZ value to 0.1 or more and 0.50 or less (see FIGS. 12 and 13).
In the present embodiment and each of the following embodiments, the quarter-wave retardation layer 9, the positive C plate 10, the color filter 11, and the color filter 11 are provided on the second substrate 12 on the antireflection film 3 side of the liquid crystal layer 8. The member in which the / 4 wavelength retardation layer 21 and the compensation layers 22 and 42 are arranged is referred to as an image display member 51 (see FIGS. 1 and 15).

[Second Embodiment]
Next, a second embodiment of the image display device of the present invention will be described.
FIG. 15 is a cross-sectional view showing the image display device according to the present embodiment in comparison with FIG.
The image display device 31 has the same configuration as the image display device 1 except that the antireflection film 33 is applied instead of the antireflection film 3. The antireflection film 33 has the same configuration as the antireflection film 3 except that the compensation layer 42 is provided instead of the compensation layer 22.
The compensation layer 42 is formed of a two-layer structure of a first compensation layer 42B and a second compensation layer 42A, and the first compensation layer 42B and the second compensation layer are sequentially arranged from the second linear polarizing plate 24 side. 42A is laminated.
The first compensation layer 42B is a negative A plate and is provided such that its slow axis is orthogonal to the transmission axis of the first linear polarizing plate 6.
The second compensation layer 42A is a retardation layer similar to the retardation layer according to the compensation layer 22 of the first embodiment described above, and its slow axis is relative to the transmission axis of the first linear polarizing plate 6. Are provided so as to be orthogonal to each other. Further, the NZ value of the second compensation layer 42A is set to 0.10 or more and 0.90 or less, preferably 0.40 or more and 0.90 or less, so that the viewing angle characteristics can be further improved.

As a result, in the antireflection film 33, the polarization state changed by the second compensation layer 42A that is the retardation layer can be further changed by the first compensation layer 42B, and the polarization state can be changed in detail. Thereby, the polarization state can be changed to the ideal position.
Therefore, it is possible to improve the viewing angle characteristics as compared with the related art and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.
In addition, since the NZ value of the second compensation layer 42A is 0.10 or more and 0.90 or less, the change of the polarization state by the first compensation layer 42B can be made smaller, and thus the contrast The decrease can be further suppressed.

FIG. 16 is a diagram showing changes in the polarization state of the image display device according to this embodiment in comparison with FIG. 5, and the emitted light emitted from the quarter-wave retardation layer 21 indicated by the symbol P1 in FIG. FIG. 4 is a diagram showing changes in the polarization state of the first compensation layer 42B and the second compensation layer 42A from the polarization state of FIG.
The first compensation layer 42B was formed of a polymerizable liquid crystal with a thickness of 0.63 μm (Re = 79.15 nm, Rth = −39.57 nm).
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 31.00 μm (Re = 84.63 nm, Rth = 0.16 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. After being changed to a different position, it is changed to a position rotated by the rotation axis (-A NZ = 0.0) related to the first compensation layer 42B, and is output by linearly polarized light corresponding to incident polarized light on the equator. Can be emitted.
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast value was simulated, the image display device of the present embodiment had the contrast values of 524 and 743 for the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 17 is a simulated contour diagram showing the characteristics of the image display device according to the present embodiment. FIG. 17A is a contour diagram of contrast values by a simulation of the image display device of this embodiment, and FIG. 17B is a diagram showing the contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

[Third Embodiment]
The image display device 31 of the present embodiment is provided with the second compensation layer 42A except that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6. The image display device of the second embodiment has the same configuration. In the second compensation layer 42A, the NZ value is formed to be 0.10 or more and 0.90 or less, but preferably 0.10 or more and 0.60 or less to further improve the viewing angle characteristics. ..
Thus, even if the second compensation layer 42A is provided so that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6, the same effect as that of the above-described embodiment is obtained. Obtainable.

FIG. 18 is a diagram showing changes in the polarization state of the image display device according to this embodiment in comparison with FIG.
The first compensation layer 42B is the same negative A plate as in the second embodiment, and is provided such that its slow axis is orthogonal to the transmission axis of the first linear polarizing plate 6.
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 171.00 μm (Re = 466.83 nm, Rth = 0.86 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. After being changed to a different position, it is changed to a position rotated by the rotation axis (-A NZ = 0.0) related to the first compensation layer 42B, and is output by linearly polarized light corresponding to incident polarized light on the equator. Can be emitted.
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast value was simulated, the image display device of the present embodiment had the contrast values of 524 and 863 in the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 19 is a contour diagram by simulation showing the characteristics of the image display device of this embodiment. FIG. 19A is a contour diagram of contrast values by simulation of the image display device of this embodiment, and FIG. 19B is a diagram showing the contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-mentioned comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristic. it can.

[Fourth Embodiment]
In this embodiment, the configuration according to the second embodiment is the same as that of the second embodiment except that the configurations of the first compensation layer 42B and the second compensation layer 42A are different from each other. This embodiment will be described in detail with reference to FIG.
In the present embodiment, the first compensation layer 42B is the same retardation layer as the retardation layer according to the compensation layer 22 of the above-described first embodiment, and the slow axis thereof is the first linear polarizing plate 6. Is provided so as to be orthogonal to the transmission axis of. Further, the NZ value of the first compensation layer 42B is formed to be 0.10 or more and 0.90 or less, but it is preferably 0.3 or more and 0.70 or less to further improve the viewing angle characteristics.
The second compensation layer 42A is a negative A plate and is provided such that its slow axis is orthogonal to the transmission axis of the first linear polarizing plate 6.

  As described above, even if the retardation layer and the negative A plate are arranged in the compensation layer by the vertical relationship opposite to that of the second embodiment, the polarization state changed by the retardation layer is changed to the negative A The polarization state can be changed in detail by changing the plate. As a result, the viewing angle characteristics can be improved as compared with the conventional case, and the contrast of the display screen can be sufficiently ensured even when the display screen is viewed from an oblique direction.

FIG. 20 is a diagram showing changes in the polarization state of the image display device according to this embodiment, and from the polarization state of the emitted light emitted from the quarter-wave retardation layer 21 indicated by the symbol P1 in FIG. It is a figure which shows the change of the polarization state by the 1st compensation layer 42B and the 2nd compensation layer 42A.
The first compensation layer 42B is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 59.50 μm (Re = 162.44 nm, Rth = 0.30 nm), and the NZ value is 0.5.
The second compensation layer 42A was formed using a polymerizable liquid crystal with a thickness of 0.48 μm (Re = 60.30 nm, Rth = −30.15 nm).

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is changed to the rotation axis (−A NZ = 0. 0) to the rotated position, and then changed to the rotated position by the rotation axis (y-axis) of the first compensation layer 42B, and the emitted polarized light by the linearly polarized light corresponding to the incident polarized light on the equator. Can be emitted.
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast values were simulated, the image display device of the present embodiment had contrast values of 524 and 999 for the viewing orientations according to FIG. 3 and the viewing orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 21 is a simulation contour diagram showing the characteristics of the image display device of the present embodiment. FIG. 21A is a contour diagram of contrast values by simulation of the image display device of the present embodiment, and FIG. 21B is a diagram showing contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

  In this embodiment, a negative A plate (second compensation layer 42A) may be provided on the opposite side of the retardation layer (first compensation layer 42B) to the side of the second linear polarizing plate 24. The polarization state can be changed in detail, which makes it possible to improve the viewing angle characteristics more reliably than before, and to ensure a sufficient display screen contrast even when viewing the display screen from an oblique direction. can do.

[Fifth Embodiment]
The image display device 31 of the present embodiment is provided with the first compensation layer 42B except that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6. The same configuration as the image display device of the fourth embodiment. Further, in the first compensation layer 42B, the NZ value is formed to be 0.10 or more and 0.90 or less, but it is preferably 0.3 or more and 0.70 or less to further improve the viewing angle characteristics. ..
Thus, even if the first compensation layer 42B is provided so that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6, the same effect as that of the above-described embodiment is obtained. Obtainable.

FIG. 22 is a diagram showing changes in the polarization state of the image display device according to this embodiment in comparison with FIG.
The first compensation layer 42B is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 144.00 μm (Re = 393.12 nm, Rth = 0.72 nm), and the NZ value is 0.5.
The second compensation layer 42A is formed of a polymerizable liquid crystal with a thickness of 0.48 μm (Re = 60.30 nm, Rth = −30.15 nm).

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is changed to the rotation axis (−A NZ = 0. 0) to the rotated position, and then changed to the rotated position by the rotation axis (y-axis) of the first compensation layer 42B, and the emitted polarized light by the linearly polarized light corresponding to the incident polarized light on the equator. Can be emitted.
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast value was simulated, the image display device of the present embodiment had the contrast values of 524 and 1227 for the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 23 is a contour diagram by simulation showing the characteristics of the image display device of this embodiment. FIG. 23 (A) is a contour diagram of contrast values by simulation of the image display device of this embodiment, and FIG. 23 (B) is a diagram showing the contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

[Sixth Embodiment]
In this embodiment, the configuration according to the second embodiment is the same as that of the second embodiment except that the configurations of the first compensation layer 42B and the second compensation layer 42A are different from each other. This embodiment will be described in detail with reference to FIG.
A positive C plate is applied to the first compensation layer 42B.
The second compensation layer 42A is a retardation layer similar to the retardation layer according to the compensation layer 22 of the first embodiment described above, and its slow axis is relative to the transmission axis of the first linear polarizing plate 6. Are provided so as to be orthogonal to each other. Although the second compensation layer 42A is formed with an NZ value of 0.10 or more and 0.90 or less, it is preferably 0.4 or more and 0.90 or less to further improve the viewing angle characteristics.

  Even when the positive C plate is arranged in the retardation layer to form the compensation layer as described above, the polarization state changed by the retardation layer can be changed in detail, and as a result, compared to the conventional case. It is possible to improve the viewing angle characteristics and sufficiently secure the contrast of the display screen even when the display screen is viewed from an oblique direction.

FIG. 24 is a diagram showing changes in the polarization state of the image display device according to the present embodiment, and shows the first polarization state of the emitted light emitted from the quarter-wave retardation layer 21 indicated by reference sign P1. It is a figure which shows the change of the polarization state by the compensation layer 42B and the 2nd compensation layer 42A.
The first compensation layer 42B is formed of a polymerizable liquid crystal with a thickness of 0.35 μm (Re = 0.00 nm, Rth = −59.85 nm).
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 49.00 μm (Re = 133.77 nm, Rth = 0.25 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. After being changed to a different position, it can be changed to a position rotated by the rotation axis (x-axis) of the first compensation layer 42B, and can be emitted as outgoing polarized light by linearly polarized light corresponding to incident polarized light on the equator. ..
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, A sufficient contrast can be secured.
More specifically, when the contrast values were simulated, the image display device of the present embodiment had contrast values of 524 and 911 respectively for the observation orientation according to FIG. 3 and the observation orientation according to FIG. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 25 is a contour map by simulation showing the characteristics of the image display device of this embodiment. FIG. 25A is a contour diagram of contrast values by simulation of the image display device of the present embodiment, and FIG. 25B is a diagram showing contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

  In this embodiment, even if a positive C plate (first compensation layer 42B) is provided on the side of the second linear polarizing plate 24 of the retardation layer (second compensation layer 42A), the polarization is detailed. It is possible to change the state, so that the viewing angle characteristics can be improved more reliably than before, and the contrast of the display screen can be sufficiently secured even when the display screen is viewed from an oblique direction. ..

[Seventh Embodiment]
The image display device 31 of the present embodiment is provided with the second compensation layer 42A except that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6. The image display device of the sixth embodiment has the same configuration. In addition, in the second compensation layer 42A, the NZ value is formed to be 0.10 or more and 0.90 or less, but it is preferably 0.1 or more and 0.60 or less to further improve the viewing angle characteristics. ..
Even if the second compensation layer 42A is provided so that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6 as described above, the same as in the above-described sixth embodiment. The effect can be obtained.

FIG. 26 is a diagram showing changes in the polarization state of the image display device according to this embodiment in comparison with FIG.
The first compensation layer 42B was formed using a polymerizable liquid crystal with a thickness of 0.35 μm (Re = 0.00 nm, Rth = −59.85 nm).
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 154.00 μm (Re = 420.42 nm, Rth = 0.77 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. After being changed to a different position, it can be changed to a position rotated by the rotation axis (x-axis) of the first compensation layer 42B, and can be emitted as outgoing polarized light by linearly polarized light corresponding to incident polarized light on the equator. ..
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast value was simulated, the image display device of the present embodiment had the contrast values of 524 and 716 for the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 27 is a contour diagram by simulation showing the characteristics of the image display device of the present embodiment. FIG. 27A is a contour diagram of the contrast value by the simulation of the image display device of the present embodiment, and FIG. 27B is a diagram showing the contour line values of the contrast value in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

[Eighth Embodiment]
In this embodiment, the configuration according to the second embodiment is the same as that of the second embodiment except that the configurations of the first and second compensation layers 42A and 42B are different. This embodiment will be described in detail using 15.
The first compensation layer 42B is a retardation layer similar to the retardation layer according to the compensation layer 22 of the first embodiment described above, and its slow axis is relative to the transmission axis of the first linear polarizing plate 6. Are provided so as to be orthogonal to each other. Although the second compensation layer 42A is formed with an NZ value of 0.10 or more and 0.90 or less, it is preferably 0.10 or more and 0.60 or less to further improve the viewing angle characteristics.
A positive C plate is applied to the second compensation layer 42A.

  Thus, the positive C plate (second compensation layer 42A) is arranged on the opposite side of the retardation layer (first compensation layer 42B) from the second linear polarizing plate 24 to form the compensation layer 42. However, the polarization state changed by the retardation layer can be changed in detail, thereby improving the viewing angle characteristics as compared with the conventional one, and even when the display screen is viewed from an oblique direction, the display screen It is possible to secure a sufficient contrast.

FIG. 28 is a diagram showing changes in the polarization state of the image display device according to the present embodiment, and shows the first polarization state of the emitted light emitted from the quarter-wave retardation layer 21 indicated by the symbol P1. It is a figure which shows the change of the polarization state by the compensation layer 42B and the 2nd compensation layer 42A.
The first compensation layer 42B is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 108.00 μm (Re = 294.84 nm, Rth = 0.54 nm), and the NZ value is 0.5.
The second compensation layer 42A is formed of a polymerizable liquid crystal with a thickness of 0.42 μm (Re = 0.00 nm, Rth = −71.82 nm).

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (x axis) of the second compensation layer 42A. After changing to a different position, it can be changed to a position rotated by the rotation axis (y-axis) of the first compensation layer 42B, and can be emitted as outgoing polarized light by linearly polarized light corresponding to incident polarized light on the equator. ..
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, A sufficient contrast can be secured.
More specifically, when the contrast values were simulated, the image display device of the present embodiment had the contrast values of 524 and 1370 in the viewing directions according to FIG. 3 and the viewing direction according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 29 is a contour map by simulation showing the characteristics of the image display device of this embodiment. FIG. 29 (A) is a contour diagram of the contrast value by the simulation of the image display device of this embodiment, and FIG. 29 (B) is a diagram showing the contour line values of the contrast value in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

  In this embodiment, a positive C plate (second compensation layer 42A) may be provided on the opposite side of the retardation layer (first compensation layer 42B) to the side of the second linear polarizing plate 24. The polarization state can be changed in detail, which makes it possible to improve the viewing angle characteristics more reliably than before, and to ensure a sufficient display screen contrast even when viewing the display screen from an oblique direction. can do.

[Ninth Embodiment]
The image display device 31 of the present embodiment is provided with the first compensation layer 42B except that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6. The image display device of the eighth embodiment has the same configuration. Further, although the first compensation layer 42B is formed with an NZ value of 0.10 or more and 0.90 or less, it is preferably 0.40 or more and 0.90 or less to further improve the viewing angle characteristics.

  Even if the first compensation layer 42B is provided so that the in-plane slow axis is parallel to the transmission axis of the first linear polarizing plate 6 as described above, the same as in the above-described eighth embodiment. The effect can be obtained.

FIG. 30 is a diagram showing changes in the polarization state of the image display device according to this embodiment in comparison with FIG.
The first compensation layer 42B is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 95.00 μm (Re = 259.35 nm, Rth = 0.48 nm), and the NZ value is 0.5.
The second compensation layer 42A is formed of a polymerizable liquid crystal with a thickness of 0.42 μm (Re = 0.00 nm, Rth = −71.82 nm).

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (x axis) of the second compensation layer 42A. After changing to a different position, it can be changed to a position rotated by the rotation axis (y-axis) of the first compensation layer 42B, and can be emitted as outgoing polarized light by linearly polarized light corresponding to incident polarized light on the equator. ..
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast values were simulated, the image display device of the present embodiment had the contrast values of 524 and 854 for the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 31 is a simulated contour diagram showing the characteristics of the image display device of the present embodiment. FIG. 31A is a contour diagram of contrast values by simulation of the image display device of this embodiment, and FIG. 31B is a diagram showing the contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

[Tenth Embodiment]
In this embodiment, the configuration according to the second embodiment is the same as that of the second embodiment except that the configurations of the first compensation layer 42B and the second compensation layer 42A are different from each other. This embodiment will be described in detail with reference to FIG.
In the present embodiment, the first compensation layer 42B is a positive A plate and is provided such that its slow axis is parallel to the transmission axis of the first linear polarizing plate 6.
The second compensation layer 42A is a retardation layer similar to the retardation layer according to the compensation layer 22 of the first embodiment described above, and its slow axis is relative to the transmission axis of the first linear polarizing plate 6. Are provided so that they are parallel to each other. The NZ value of the second compensation layer 42A is formed to be 0.10 or more and 0.90 or less, but preferably 0.10 or more and 0.60 or less.

FIG. 32 is a diagram showing changes in the polarization state of the image display device according to this embodiment.
The first compensation layer 42B was formed of a cycloolefin polymer resin with a thickness of 28.00 μm (Re = 68.60 nm, Rth = 34.30 nm, NZ = 1.0).
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 87.00 μm (Re = 237.51 nm, Rth = 0.44 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. To a position rotated by the rotation axis (+ A NZ1.0) of the first compensation layer 42B after being changed to a different position, and emitted by outgoing polarized light by linear polarized light corresponding to incident polarized light on the equator. You can
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, A sufficient contrast can be secured.
More specifically, when the contrast values were simulated, the image display device of the present embodiment had contrast values of 524 and 692 for the viewing orientations according to FIG. 3 and the viewing orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 33 is a simulated contour diagram showing the characteristics of the image display device of the present embodiment. FIG. 33A is a contour diagram of contrast values by simulation of the image display device of the present embodiment, and FIG. 33B is a diagram showing the contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

  In this embodiment, even if a positive A plate (first compensation layer 42B) is provided on the side of the second linear polarizing plate 24 of the retardation layer (second compensation layer 42A), the polarized light is detailed. It is possible to change the state, so that the viewing angle characteristics can be improved more reliably than before, and the contrast of the display screen can be sufficiently secured even when the display screen is viewed from an oblique direction. ..

[Eleventh Embodiment]
The image display device 31 of the present embodiment, except that the second compensation layer 42A is provided so that the in-plane slow axis is orthogonal to the transmission axis of the first linear polarizing plate 6, It has the same configuration as the image display device of the tenth embodiment. In addition, the second compensation layer 42A is formed with an NZ value of 0.10 or more and 0.90 or less, but preferably 0.40 or more and 0.90 or less.
Even if the second compensation layer 42A is provided so that the in-plane slow axis is orthogonal to the transmission axis of the first linear polarizing plate 6 as described above, the same effect as in the above-described tenth embodiment is obtained. Can be obtained.

FIG. 34 is a diagram showing changes in the polarization state of the image display device according to this embodiment in comparison with FIG.
The first compensation layer 42B is formed of a cycloolefin polymer resin with a thickness of 28.00 μm (Re = 68.60 nm, Rth = 34.30 nm, NZ = 1.0).
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 116.00 μm (Re = 316.68 nm, Rth = 0.58 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. To a position rotated by the rotation axis (+ A NZ1.0) of the first compensation layer 42B after being changed to a different position, and emitted by outgoing polarized light by linear polarized light corresponding to incident polarized light on the equator. You can
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast values were simulated, the image display device of the present embodiment had contrast values of 524 and 972 for the viewing orientations according to FIG. 3 and the viewing orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 35 is a contour diagram by simulation showing the characteristics of the image display device of the present embodiment. FIG. 35 (A) is a contour diagram of contrast values by simulation of the image display device of the present embodiment, and FIG. 35 (B) is a diagram showing the contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

[Twelfth Embodiment]
In this embodiment, the configuration according to the second embodiment is the same as that of the second embodiment except that the configurations of the first compensation layer 42B and the second compensation layer 42A are different from each other. This embodiment will be described in detail with reference to FIG.
In this embodiment, a negative C plate is applied to the first compensation layer 42B.
The second compensation layer 42A is a retardation layer similar to the retardation layer according to the compensation layer 22 of the first embodiment described above, and its slow axis is relative to the transmission axis of the first linear polarizing plate 6. Are provided so that they are parallel to each other. The second compensation layer 42A is formed with an NZ value of 0.10 or more and 0.90 or less, but preferably 0.10 or more and 0.6 or less.

FIG. 36 is a diagram showing changes in the polarization state of the image display device according to this embodiment.
The first compensation layer 42B was formed of a film material of triacetyl cellulose resin having a thickness of 65.50 μm (Re = 0.00 nm, Rth = 47.16 nm).
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 102.00 μm (Re = 278.46 nm, Rth = 0.51 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. After being changed to a different position, the first compensation layer 42B can be changed to a position rotated by the rotation axis (x axis) of the first compensation layer 42B, and can be emitted as outgoing polarized light by linearly polarized light corresponding to incident polarized light on the equator. .
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, A sufficient contrast can be secured.
More specifically, when the contrast value was simulated, the image display device of the present embodiment had the contrast values of 524 and 928 for the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 37 is a contour map by simulation showing the characteristics of the image display device of this embodiment. FIG. 37 (A) is a contour diagram of contrast values by simulation of the image display device of the present embodiment, and FIG. 37 (B) is a diagram showing the contour line values of the contrast values in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

  In this embodiment, even if a negative C plate (first compensation layer 42B) is provided on the side of the second linear polarizing plate 24 of the retardation layer (second compensation layer 42A), the polarization will be detailed. It is possible to change the state, so that the viewing angle characteristics can be improved more reliably than before, and the contrast of the display screen can be sufficiently secured even when the display screen is viewed from an oblique direction. ..

[Thirteenth Embodiment]
The image display device of the present embodiment is different from the image display device of the first embodiment except that the second compensation layer 42A is provided so that the in-plane slow axis is orthogonal to the transmission axis of the first linear polarizing plate 6. The image display device of the twelfth embodiment has the same configuration. The second compensation layer 42A is formed with an NZ value of 0.10 or more and 0.90 or less, but preferably 0.40 or more and 0.90 or less.
Even if the second compensation layer 42A is provided so that the in-plane slow axis is orthogonal to the transmission axis of the first linear polarizing plate 6 as described above, the same effect as the above-described twelfth embodiment is obtained. Can be obtained.

FIG. 38 is a diagram showing changes in the polarization state of the image display device according to this embodiment in comparison with FIG.
The first compensation layer 42B was formed of a film material of triacetyl cellulose resin having a thickness of 65.50 μm (Re = 0.00 nm, Rth = 47.16 nm).
The second compensation layer 42A is formed by applying a biaxially stretched polycarbonate film material and having a thickness of 102.00 μm (Re = 278.46 nm, Rth = 0.51 nm), and the NZ value is 0.5.

In this embodiment, as shown by the arrow, the polarization state (P1) of the emitted light emitted from the quarter-wave retardation layer 21 is rotated by the rotation axis (y-axis) of the second compensation layer 42A. After being changed to a different position, it can be changed to a position rotated by the rotation axis (x-axis) of the first compensation layer 42B, and can be emitted as outgoing polarized light by linearly polarized light corresponding to incident polarized light on the equator. ..
As a result, in this embodiment, the emitted light can be emitted by almost ideal emission polarization, and as a result, the viewing angle characteristics are improved as compared with the conventional case, and even when the display screen is viewed from an oblique direction, It is possible to sufficiently secure the contrast of the display screen.
More specifically, when the contrast value was simulated, the image display device of the present embodiment had the contrast values of 523 and 708 for the observation orientation according to FIG. 3 and the observation orientation according to FIG. 4, respectively. The contrast value is a value when observed from the direction of 60 degrees from the panel normal. As a result, the image display device of the present embodiment has improved viewing angle characteristics as compared with the image display device of each comparative example, and sufficiently secures the contrast of the display screen even when viewing the display screen from an oblique direction. You can see that you can.

FIG. 39 is a simulated contour diagram showing the characteristics of the image display device of this embodiment. FIG. 39 (A) is a contour diagram of the contrast value by the simulation of the image display device of the present embodiment, and FIG. 39 (B) is a diagram showing the contour line values of the contrast value in this contour diagram.
With the configuration of the present embodiment, it is confirmed that the change in the contrast value due to the change in the viewing direction is smaller than that of the image display device of the above-described comparative example, and thus it is possible to sufficiently secure the improvement of the viewing angle characteristics. it can.

  40 and 41 are tables summarizing the configurations of the first to thirteenth embodiments. 40 and 41, the angle is the angle of the transmission axis of the second linear polarizing plate when the direction of the transmission axis of the first linear polarizing plate 6 is 0 degree (horizontal), and each layer (compensation layer, The angle of the slow axis of the quarter-wave retardation layer) is shown, and the arrows in parentheses schematically show the directions of the transmission axis and the slow axis.

[Fourteenth Embodiment]
In this embodiment, the whole or part of the antireflection portion formed by the antireflection film 3 is sequentially formed on the substrate 12 on the emission surface side of the image display panel. Specifically, all or part of the linear polarizing plate 24, the compensation layer 22, and the quarter-wave retardation layer 21 are sequentially formed in the substrate 12 on the emission surface side of the image display panel.
As a result, the structure relating to the antireflection film can be simplified, and further the entire structure can be simplified.

In this case, the compensation layer 22 (42) and the quarter-wave retardation layer 21 described above are sequentially coated on the substrate 12 by applying and curing the corresponding ultraviolet curable liquid crystal, thermosetting liquid crystal, or the like. Can be created. An alignment film or the like may be appropriately added as a base layer for liquid crystal application.
The linearly polarizing plate 24 can be formed on the compensation layer 22 (42) by applying a so-called coating type structure.
This embodiment has the same configuration as each of the above-described embodiments except that the configuration related to the antireflection film is different.
Even if the whole or part of the antireflection portion formed by the antireflection film 3 is sequentially formed on the emission surface side substrate 12 of the image display panel as in this embodiment, the same as in the above-described embodiments. The effect can be obtained.

[Fifteenth Embodiment]
In this embodiment, in the configuration of each of the above-described embodiments, the sensor film for a touch panel is provided on the most exit surface side, and thus the function of the touch panel is provided in the image display panel. Further, the touch panel sensor film may be arranged between the quarter-wave retardation layer 21 of the image display device and the second substrate 12. Thereby, the image display device can reduce the reflection of external light by the sensor film for a touch panel by the antireflection film 3.
This embodiment has the same configuration as each of the above-described embodiments except that the configuration relating to the touch panel sensor film is different.
Even if a sensor film for a touch panel is provided as in this embodiment, it is possible to obtain the same effects as those of the above-described embodiments.
It should be noted that the image display device may be provided with a transparent electrode that reduces radiation of electromagnetic waves due to driving of the liquid crystal layer 8. By disposing the transparent electrode between the quarter-wave retardation layer 21 and the second substrate 12, for example, it is possible to reduce reflection of external light by the transparent electrode and efficiently reduce unnecessary radiation. it can.
Further, an antireflection layer may be further provided on the outermost surface of the antireflection film 3.

[Other Embodiments]
The specific configuration suitable for carrying out the present invention has been described above in detail, but the present invention can variously change the configuration of the above-described embodiment without departing from the spirit of the present invention.
In the above-described embodiment, the example in which the quarter-wave retardation layer 9, the positive C plate 10, and the color filter 11 are sequentially provided on the liquid crystal layer 8 has been described, but the present invention is not limited to this and the liquid crystal A quarter-wave retardation layer 9, a color filter 11, and a positive C plate 10 may be sequentially provided on the layer 8.
Further, in each of the above-described embodiments, the example in which the positive C plate 10 is provided on the side of the quarter-wave retardation layer 9 of the substrate 12 has been shown, but it is on the side of the quarter-wave retardation layer 21 of the substrate 12. A positive C plate 10 may be provided.

1, 31 Image display device 2 Image display panel 3, 33 Antireflection film 4 Backlight 5 Liquid crystal cell 6, 24 Linear polarizing plate 7, 12 Substrate 8 Liquid crystal layer 9, 21 1/4 wavelength retardation layer 10 Positive C plate 11 Color Filters 22, 42, 42A, 42B Compensation Layer 51 Image Display Member

Claims (22)

A liquid crystal layer is provided between the first substrate and the second substrate held so as to face each other,
On the opposite side of the first substrate from the liquid crystal layer, a first linear polarizing plate that emits linearly polarized light incident from a backlight is arranged.
A second linear polarizing plate is disposed on the side of the second substrate opposite to the liquid crystal layer so that the transmission axis is orthogonal to the first linear polarizing plate.
A first quarter-wave retardation layer whose slow axis forms an angle of 45 degrees with the transmission axis of the first linear polarizing plate is provided between the liquid crystal layer and the second substrate. ,
A second quarter-wave retardation layer in which a slow axis and a slow axis of the first quarter-wave retardation layer are orthogonal to each other between the second substrate and the second linear polarizing plate. Is provided,
A positive C plate is provided between the first quarter-wave retardation layer and the second quarter-wave retardation layer,
A compensation layer including a retardation layer having an NZ value of 0.10 or more and 0.90 or less is provided between the second linear polarizing plate and the second ¼ wavelength retardation layer,
An image display device, wherein an angle formed by a slow axis of the second quarter-wave retardation layer and a slow axis of the retardation layer is 45 degrees. The retardation layer of the compensation layer,
The image display device according to claim 1, wherein the slow axis is arranged so as to be orthogonal to the transmission axis of the first linear polarizing plate. The retardation layer of the compensation layer,
The image display device according to claim 1, wherein the slow axis is arranged so as to be parallel to the transmission axis of the first linear polarizing plate. The compensation layer is
The negative A plate arranged so that the slow axis is orthogonal to the transmission axis of the first linear polarizing plate is provided on the side of or opposite to the second linear polarizing plate of the retardation layer. The image display device according to claim 3. The compensation layer is
The image display device according to any one of claims 1 to 3, further comprising a positive C plate on a side of or opposite to the second linear polarization plate of the retardation layer. The compensation layer is
The positive A plate arranged so that the slow axis is parallel to the transmission axis of the first linear polarizing plate is provided on the second linear polarizing plate side of the retardation layer. Item 4. The image display device according to any one of Items 3 to 3. The compensation layer is
The image display device according to claim 1, further comprising a negative C plate on the side of the second linear polarizing plate of the retardation layer. The liquid crystal layer is a liquid crystal layer in a lateral electric field mode,
The image display device according to claim 1, wherein a transparent electrode in the lateral electric field mode is formed on the first substrate. The image display device according to any one of claims 1 to 8, wherein a color filter is provided on the second substrate. The image display device according to any one of claims 1 to 9, further comprising a sensor film for a touch panel. The image display device according to claim 1, wherein the retardation layer has a slow axis parallel to the transmission axis of the first linear polarizing plate and an NZ value of 0.50 or more and 0.85 or less. The image display device according to claim 1, wherein the retardation layer has a slow axis orthogonal to the transmission axis of the first linear polarizing plate and an NZ value of 0.1 or more and 0.5 or less. A first quarter-wave retardation layer is provided on one surface side of the substrate,
On the other surface side of the substrate, a second quarter-wave retardation layer having a slow axis orthogonal to the slow axis of the first quarter-wave retardation layer, and an NZ value of 0.10. And a compensating layer having a retardation layer of 0.90 or less,
The angle formed by the slow axis of the second quarter-wave retardation layer and the slow axis of the retardation layer is 45 degrees,
An image display member, wherein a positive C plate is provided between the first quarter-wave retardation layer and the second quarter-wave retardation layer. The compensation layer comprises a negative A plate,
The image display member according to claim 13, wherein an angle formed by the slow axis of the negative A plate and the slow axis of the second quarter-wave retardation layer is 45 degrees. The image display member according to claim 13, wherein the compensation layer includes a positive C plate. The compensation layer comprises a positive A plate,
The retardation layer is provided between the positive A plate and the second quarter-wave retardation layer,
The image display member according to claim 13, wherein the slow axis of the positive A plate and the slow axis of the second quarter-wave retardation layer form an angle of 45 degrees. The compensation layer comprises a negative C plate,
The image display member according to claim 13, further comprising the retardation layer between the negative C plate and the second quarter-wave retardation layer. A compensation layer provided with a retardation layer having an NZ value of 0.10 or more and 0.90 or less is provided between the linear polarizing plate and the 1/4 wavelength retardation layer,
The transmission axis of the linear polarizing plate and the slow axis of the ¼ wavelength retardation layer form an angle of 45 degrees,
An optical member in which a transmission axis of the linear polarizing plate and a slow axis of the retardation layer are parallel or orthogonal to each other. The compensation layer comprises a negative A plate,
The optical member according to claim 18, wherein a slow axis of the negative A plate and a transmission axis of the linear polarizing plate are parallel to each other. The optical member according to claim 18, wherein the compensation layer includes a positive C plate. The compensation layer comprises a positive A plate,
The phase difference layer is provided between the positive A plate and the quarter wavelength phase difference layer,
The optical member according to claim 18, wherein a slow axis of the positive A plate and a transmission axis of the linear polarizing plate are orthogonal to each other. The compensation layer comprises a negative C plate,
The optical member according to claim 18, comprising the retardation layer between the negative C plate and the quarter-wave retardation layer.

Images