JP2011257610A - On-vehicle display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and simple on-vehicle display device capable of suppressing the reflection of a display image in a driver's viewpoint position of a wide range, without generating Moire and the like and degrading transmissivity.SOLUTION: An on-vehicle display device comprises at least a liquid crystal panel 303 arranged in a front slanting direction to a visually recognizing person 302, and irradiating polarization to a visually recognizing side, and a phase difference film 313 laminated on the visually recognizing side of the liquid crystal panel. The polarization has a polarization axis 304 in a substantially vertical direction on a display surface.

Description

  The present invention relates to an in-vehicle display device, and more particularly to an in-vehicle display device capable of suppressing the display image from being reflected on a windshield.

  In the in-vehicle display device, the display image is reflected by the windshield, and when it is reflected, the driver's driving field of view is obstructed. For example, as shown in FIG. 10, light 1011 emitted from the display screen of the in-vehicle display device 1003 and incident on the windshield 1001 is reflected at the interface of the windshield 1001 and becomes reflected light 1012 to be the field of view of the driver 1002. Incident to Such reflected light 1012 is recognized by the driver 1002 as being reflected on the windshield and obstructs the driving field of view of the driver 1002.

  In order to control the light from the display screen in a predetermined direction due to such problems, there is a light control film (hereinafter referred to as LCF) using a louver-like structure manufactured by a method as described in Patent Document 1. Used.

  As another technique, Patent Document 2 proposes a method of rotating a polarizer of light emitted from the display surface of a liquid crystal display device and darkening a reflected image presented on the display surface reflected on the upper left portion of the windshield. Has been.

JP-T-2004-514167 JP-A-01-302383

  However, the LCF disclosed in Patent Document 1 has a problem that moire may occur between the pixel arrangement of the display device and the transmittance of the display screen decreases. Furthermore, such an LCF cannot be reduced due to complicated manufacturing processes.

  Further, in the method of adjusting the transmission axis of the polarizing plate on the front surface of the display surface as described in Patent Document 2, the range in which the reflected image can be darkened is narrow, and the driver's viewpoint for obtaining the effect of suppressing reflection is There is a problem that it is limited to the narrow range.

The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide an in-vehicle display device capable of suppressing the reflection of a display image at a driver viewpoint position in a wider range than before. That is.
Another object of the present invention is to provide an in-vehicle display device capable of suppressing the occurrence of moire or the like and the decrease in transmittance.
Still another object of the present invention is to provide an in-vehicle display device that can be applied to a VA-type or IPS-type liquid crystal panel and can suppress display image reflection, moire, and the like, and a decrease in transmittance. It is.

  As a result of earnest research to achieve the above-mentioned problems, the inventor has a specific phase difference with respect to the display side (or the viewer side) of the liquid crystal panel whose emitted light has a viewing-side transmission axis in a specific direction. It has been found that when a film is provided, the direction of linearly polarized light emitted from the liquid crystal panel can be controlled, thereby suppressing the reflection of the displayed image even when the driver's viewpoint is relatively wide. The present invention has been completed.

That is, the present invention is an in-vehicle display device that is disposed in a diagonally forward direction with respect to a viewer and has a display surface on the rear side that is the viewer's viewing side,
A liquid crystal panel that emits polarized light toward the viewing side;
At least one retardation film disposed on the viewing side of the liquid crystal panel;
Comprising at least
The polarized light has a polarization axis in a substantially vertical direction on the display surface;
The retardation film is an in-vehicle display device that corrects the polarization direction of polarized light emitted from the polarizing element to a P polarization direction with respect to a windshield of a vehicle.

  In this in-vehicle display device, the retardation film may have an Nz coefficient of 0.4 ≦ Nz ≦ 0.6, and the retardation film may be a half-wave plate (in particular, one of positive A plates). / 2 wavelength plate).

  Further, the retardation film may have a laminated structure of a plurality of retardation films. As such a laminated structure, (i) a first retardation film that is a positive C plate and a positive A plate (Ii) a structure in which a first retardation film that is a negative A plate and a second retardation film that is a negative C plate are laminated, or (iii) ) A structure in which a first retardation film having an Nz coefficient of Nz = 0.75 and a second retardation film having an Nz coefficient of Nz = 0.25 are stacked.

  In such an on-vehicle display device, it is preferable that the in-plane slow axis of at least one retardation film is parallel or perpendicular to the polarization transmission axis of the viewing side polarizing plate.

  Further, the in-vehicle display device includes a structure having a touch panel between a liquid crystal panel and a retardation film.

  Here, the polarized light emitted from the liquid crystal panel to the viewer side may be light polarized by laminating a polarizing element on the viewer side of the liquid crystal panel. However, the polarized light already defined by the present invention in the liquid crystal display device may be used. If it has a transmission axis, it can be used as it is. The polarized light emitted from the liquid crystal panel is emitted from a light source disposed on the liquid crystal panel, and a known or commonly used light source in a liquid crystal display device can be used as the light source.

  Further, with respect to the direction of the viewing-side surface polarization transmission axis, the substantially vertical direction on the display surface means that the line intersecting the vertical cross section including the normal line direction to the display screen is 0 degrees in the vertical direction with respect to the display screen. It means that the transmission axis exists within a range of about −15 degrees to +15 degrees.

  In the present invention, polarized light having a specific polarization transmission axis is emitted from the liquid crystal panel, and this polarized light is corrected in a predetermined direction by a retardation film. Thus, the display image can be prevented from being reflected in a relatively wide range of driver viewpoint positions without causing the occurrence of the occurrence of the image and the significant decrease in the transmittance.

  In addition, when a retardation film having a specific retardation is combined, reflection of light with a wider wavelength can be suppressed.

  Further, even when the in-vehicle display device has a touch panel, the in-vehicle display device of the present invention can suppress the reflection of the display image in a relatively wide range of driver viewpoint positions.

It is a schematic perspective view for demonstrating the Brewster angle with respect to a reflective surface. It is a schematic front view for demonstrating a mode that a reflected image generate | occur | produces on a windshield. It is a schematic front view for demonstrating the state by which the vehicle-mounted display apparatus of the 1st Embodiment of this invention is attached in the vehicle. It is a schematic perspective view for demonstrating 2nd Embodiment of the vehicle-mounted display apparatus of this invention. It is a schematic perspective view for demonstrating 3rd Embodiment of the vehicle-mounted display apparatus of this invention. It is a schematic perspective view for demonstrating 4th Embodiment of the vehicle-mounted display apparatus of this invention. It is a schematic perspective view for demonstrating 5th Embodiment of the vehicle-mounted display apparatus of this invention. It is a schematic perspective view for demonstrating 6th Embodiment of the vehicle-mounted display apparatus of this invention. It is a schematic perspective view for demonstrating 7th Embodiment of the vehicle-mounted display apparatus of this invention. It is a schematic sectional drawing for demonstrating a mode that a display image reflects on a windshield in the conventional vehicle-mounted display apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the illustrated form.

  First, the principle of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view for explaining the Brewster angle with respect to the reflecting surface, and FIG. 2 is a schematic front view for explaining a reflected image generated on the windshield.

As shown in FIG. 1, when light 102 is incident at an angle with respect to an interface between two materials having different refractive indexes, a P-polarized light component 103 perpendicular to the interface (or reflection surface) 101 and a reflection surface It is known that the S-polarized light component 104 parallel to 101 has a different reflectance. The reflectance of the P-polarized light component 103 becomes zero when the incident angle 105 becomes the Brewster angle (θ _B ).

This Brewster angle (θ _B ) is generally represented by the following formula (1), for example, reflection at the interface of air (incident side: refractive index 1.0) / glass (transmission side: refractive index 1.5). Is about 56 degrees.
tan θ _B = n ₂ / n ₁ (1)
In the formula, n ₁ is the refractive index of the incident side material, and n ₂ is the refractive index of the transmission side.

  As shown in FIG. 2, in a vehicle having a windshield 201 in the front, the in-vehicle display device 203 is generally disposed obliquely forward with respect to the driver 202, and in the vicinity of the center in the width direction of the vehicle. It is arranged. This in-vehicle display device 203 has a display surface on the rear side which is the viewing side with respect to the driver 202. In the in-vehicle display device 203, a polarizing element having a polarization transmission axis 204 in a substantially vertical direction on the display surface is disposed on the viewing side. Therefore, light that vibrates in the direction of the transmission axis 204 through the polarization element. Only is emitted. That is, the polarization component that vibrates in the horizontal direction is lost by the polarizing element.

  The polarization direction of the incident light 209 emitted from the display surface of the in-vehicle display device 203 toward the center of the vehicle and incident on the windshield 201 is a polarization component perpendicular to the reflection surface when incident on the windshield 201. The direction is the same as the P polarization direction 207. If the incident angle of the incident light 209 is near the Brewster angle, the P-polarized component is hardly reflected, so that the generation of the reflected light 210 due to the P-polarized component can be suppressed. Become.

  On the other hand, the driver 202 is not only located in the diagonally backward direction of the in-vehicle display device 203, but the viewpoint position may move. In the light 211 emitted obliquely from the in-vehicle display device 203 and incident on the windshield 201, the polarization direction is shifted from the P-polarization direction 208 even if the polarization component oscillating in the horizontal direction disappears. . Therefore, when the incident light 212 is reflected from the windshield 201 toward the visual field direction of the driver 202, reflected light 212 is generated, and the driver 202 recognizes it as a reflection.

  A first embodiment of the in-vehicle display device of the present invention is shown in FIG. In FIG. 3, an in-vehicle display device 303 provided with a retardation film 313 is provided instead of the in-vehicle display device 202 in FIG. 2. The in-vehicle display device 303 includes a liquid crystal panel that emits polarized light having a polarization transmission axis 304 in a substantially vertical direction on the display surface, and a retardation film 313 disposed on the viewing side of the liquid crystal panel.

  Note that the direction of the in-plane slow axis of the retardation film 313 can be appropriately set according to the position of the display device, the shape of the windshield, and the like. Further, the display surface itself may be installed with an azimuth angle or an inclination angle so that the viewer can easily see.

  In this case, the polarized light 309 emitted from the display surface of the in-vehicle display device 303 toward the windshield 301 toward the center of the vehicle has a polarization axis 305. Similar to the in-vehicle display device 203, the polarization axis 305 is in the same direction as the P-polarization direction 307. Therefore, even if the polarization 309 enters the windshield 301, the generation of the reflected light 310 is suppressed.

  Further, in this in-vehicle display device 303, the retardation film 313 can correct the polarization direction 306 of the incident light 311 incident in the oblique direction of the windshield 301 in the same direction as the P polarization direction 308. Therefore, even when the incident light 311 is incident on the windshield 303, the reflected light is reflected to the driver 302 and a passenger seat (not shown) (hereinafter, both may be collectively referred to as a viewer). The effect of suppressing the occurrence of 312 and suppressing the reflection is obtained.

  As described above, by combining the emitted light emitted from the liquid crystal panel with a specific transmission axis and the retardation film capable of correcting the emitted light in a specific direction, the in-vehicle display device is inclined in the oblique direction of the viewer. Even if it is installed, even if the viewer's viewpoint position moves or the viewer's position is not constant, the display device prevents the viewer from reflecting on the windshield. be able to.

  Hereinafter, various embodiments of the in-vehicle display device of the present invention will be described in detail with reference to the drawings. FIG. 4 is a schematic perspective view of the in-vehicle display device according to the second embodiment. The display device for a vehicle body includes a liquid crystal panel 405 having a polarizing element 403 on the viewing side, and one retardation film 401 disposed on the viewing side of the liquid crystal panel 405. The retardation film 401 is disposed on the viewing side of the polarizing element 403 through an adhesive layer (not shown).

  The polarizing element 403 of the liquid crystal panel 405 has a transmission axis 404 in a substantially vertical direction on the display surface. The transmission axis 404 of the polarizing element 403 and the in-plane slow axis 402 of the retardation film 401 are perpendicular to each other on a plane parallel to the display surface (or in the display surface).

  In the present invention, the relationship between the in-plane slow axis of the retardation film and the transmission axis of the polarizing element corrects the polarized light emitted from the liquid crystal panel by the retardation film in the P-polarization direction with respect to the vehicle windshield. It is not particularly limited as long as it can. Preferably, the in-plane slow axis of the retardation film and the transmission axis of the polarizing element are perpendicular or parallel to each other.

Further, the Nz coefficient of the retardation film may be, for example, in a range of 0.4 ≦ Nz ≦ 0.6, and particularly preferably Nz = 0.5. Here, the Nz coefficient is an index representing the magnitude relationship of the three-dimensional refractive index, and is a coefficient represented by the following formula 2 when the three-dimensional refractive index components are nx, ny, and nz. In addition, the retardation film which has such Nz coefficient can be manufactured by the method as described in Unexamined-Japanese-Patent No. 2008-164925, for example.
Nz = (nx-nz) / | nx-ny | (2)
(In the formula, nx and ny are refractive indexes in the film plane, and nz is a refractive index in the normal direction to the film plane.)

  The retardation film is preferably a half-wave plate with a retardation of 180 degrees. In such a wave plate, even if the in-plane retardation in the film front direction at a wavelength of 550 nm is about 200 nm to 350 nm. Good.

  Further, the retardation film is preferably a half-wave plate of a positive A plate, and the positive A plate is represented by a relationship of three-dimensional refractive index components nx, ny, nz nx> ny = nz. It is a retardation film.

  Further, the retardation film is preferably a retardation film having a so-called birefringent reverse wavelength dispersion characteristic in which the retardation increases as the wavelength of transmitted visible light increases, and when such a film is used. It is possible to obtain the performance of preventing reflection in a wide range.

  The positive A plate can be produced using, for example, a method for producing a birefringent film described in JP-A No. 11-189665.

  Furthermore, the retardation film can be a laminate of a plurality of retardation films. As a laminate of such a retardation film, for example, (i) a structure in which a first retardation film that is a positive C plate and a second retardation film that is a positive A plate are laminated, (ii) A structure in which a first retardation film which is a negative A plate and a second retardation film which is a negative C plate are laminated, and (iii) a first retardation film whose Nz coefficient is Nz = 0.75, And a structure in which a second retardation film having an Nz coefficient of Nz = 0.25 is laminated. In these laminated structures, the liquid crystal panel side may be the first retardation film, the viewing side may be the second retardation film, the viewing side may be the first retardation film, and the liquid crystal panel side may be the first retardation film. Two retardation films may be used.

  When the retardation film is a laminate of a plurality of retardation films, the in-plane slow axis of each retardation film is perpendicular or parallel to the transmission axis of the polarizing element disposed on the viewing side of the display device. However, when the retardation film does not have an in-plane slow axis, the retardation film may be arranged in any direction. In particular, the in-plane slow axis of at least one retardation film is preferably perpendicular or parallel to each other in a plane parallel to the transmission axis of the polarizing element and the display surface.

  FIG. 5 is a schematic perspective view for explaining a third embodiment of the in-vehicle display device of the present invention. The vehicle body display device includes a liquid crystal panel 505 having a polarizing element 503 on the viewing side, a first retardation film 507 disposed on the viewing side of the liquid crystal panel 505, and a viewing side of the first retardation film 507. And a second retardation film 501 disposed on the surface. The first retardation film 507 is a positive C plate, and the second retardation film 501 is a positive A plate. The polarizing element 503, the first retardation film 507, and the second retardation film 501 are laminated in this order toward the viewing side, and are laminated and bonded via an adhesive layer.

  The polarizing element 503 of the liquid crystal panel 505 has a transmission axis 504 in a substantially vertical direction on the display surface. The transmission axis 504 of the polarizing element 503 and the in-plane slow axis 502 of the second retardation film 501 are perpendicular to each other in a plane parallel to the display surface. In addition, the in-plane slow axis 506 of the first retardation film faces the normal line direction with respect to the display surface.

  Here, the positive C plate is a retardation film in which the three-dimensional refractive index components nx, ny, and nz are represented by a relationship of nx = ny <nz. The positive C plate can be produced by using, for example, a method for producing an optically anisotropic element described in JP-A No. 2002-294240.

  In this embodiment, the first retardation film desirably has an out-of-plane retardation in the thickness direction around a wavelength of 550 nm of about −50 nm to −150 nm (preferably about −75 nm to −125 nm). The retardation film desirably has an in-plane retardation in the film front direction in the vicinity of a wavelength of 550 nm of about 100 nm to 180 nm (preferably about 120 nm to 160 nm).

  FIG. 6 is a schematic perspective view for explaining a fourth embodiment of the in-vehicle display device of the present invention. The vehicle body display device includes a liquid crystal panel 605 having a polarizing element 603 on the viewing side, a first retardation film 607 disposed on the viewing side of the liquid crystal panel 605, and a viewing side of the first retardation film 607. The second retardation film 601 is provided. The first retardation film 607 is a negative A plate, and the second retardation film 601 is a negative C plate. The polarizing element 603, the first retardation film 607, and the second retardation film 601 are laminated in this order toward the viewing side, and are laminated and bonded via an adhesive layer.

  In this example, the transmission axis 604 of the polarizing element 603 and the in-plane slow axis 606 of the first retardation film 607 are parallel to each other in a plane parallel to the display surface. In addition, the in-plane slow axis 602 of the second retardation film faces the normal line direction with respect to the display surface.

Here, the negative A plate is a retardation film in which the three-dimensional refractive index components nx, ny, and nz are represented by a relationship of nx = nz> ny, and the negative C plate is a three-dimensional refractive index component nx, ny, ny. In the retardation film, nz is represented by a relationship of nx = ny> nz.
The negative A plate can be produced using, for example, a method for producing an optical compensation sheet described in JP-A-10-54982, and the negative C plate can be produced, for example, in JP-A-2006-78617. It can produce using the manufacturing method of the optical film of description, etc.

  In this embodiment, it is desirable that the first retardation film has an in-plane retardation in the film front direction in the vicinity of a wavelength of 550 nm of about 100 nm to 180 nm (preferably about 120 nm to 160 nm), and the second retardation film is The out-of-plane retardation in the thickness direction near the wavelength of 550 nm is desirably about 70 to 110 nm (preferably about 80 to 100 nm).

  FIG. 7 is a schematic perspective view for explaining a fifth embodiment of the in-vehicle display device of the present invention. The vehicle body display device includes a liquid crystal panel 705 having a polarizing element 703 on the viewing side, a first retardation film 707 disposed on the viewing side of the liquid crystal panel 705, and a viewing side of the first retardation film 707. The second retardation film 701 is provided.

  The first retardation film 707 satisfies 0.2 ≦ Nz ≦ 0.3, and the second retardation film 701 satisfies 0.7 ≦ Nz ≦ 0.8. The polarizing element 703, the first retardation film 707, and the second retardation film 701 are laminated in this order toward the viewing side, and are laminated and bonded via an adhesive layer.

  In this example, the first retardation film 707 and the second retardation film 701 have in-plane slow axes laminated in parallel on a plane parallel to the display surface. Further, the slow axes 706 of the second retardation film 707 are arranged in parallel to each other on a plane parallel to the transmission axis 704 of the polarizing element 703 and the display surface.

  In this embodiment, it is desirable that the first and second retardation films have an in-plane retardation of about 200 nm to 350 nm (preferably about 220 nm to 330 nm) in the film front direction near a wavelength of 550 nm. By adopting such a structure, it becomes possible to suppress the reflection of light with a broader wavelength.

  The in-plane retardation of the first and second retardation films may be the same or different, but the ratio of the retardations of the first retardation film and the second retardation film is ( The former) / (the latter) is preferably about 70/30 to 30/70, and more preferably about 60/40 to 40/60.

  The in-vehicle display device of the present invention may have a structure in which a touch panel is disposed between the liquid crystal panel and the retardation film. As long as the retardation film is within the scope of the present invention, the above-described various forms can be used.

  FIG. 8 is a schematic perspective view of a vehicle-mounted display device according to a sixth embodiment in which a touch panel is provided. In this example, the display device for a vehicle body includes a liquid crystal panel 805 having a polarizing element 803 on the viewing side, a touch panel 809 disposed on the viewing side of the polarizing element 803, and 1 disposed on the viewing side of the touch panel 809. Sheet of retardation film 801. Other configurations are the same as those in the first embodiment except that the touch panel 809 is inserted between the liquid crystal panel 805 and the retardation film 801.

  FIG. 9 is a schematic perspective view of the on-vehicle display device according to the seventh embodiment. In this in-vehicle display device, in place of the touch panel 809 used in the sixth embodiment, a touch panel 909 in which a second polarizing element 907 is disposed on the viewing side of the touch panel element 908 is disposed.

  That is, this in-vehicle display device is provided on the viewing side of the liquid crystal panel 905 having the first polarizing element 903 on the viewing side, the touch panel 909 disposed on the viewing side of the polarizing element 903, and the viewing side of the touch panel 909. The touch panel 909 includes a touch panel element 908 and a second polarizing element 907 disposed on the viewing side thereof. Here, the second polarizing element 907 has a transmission axis 404 in a substantially vertical direction on the display surface, and plays a role of preventing external light incident on the touch panel 909 from being reflected.

  In this example, the touch panel 909 uses the second polarizing element 907 to prevent reflection of external light. However, the touch panel 909 includes the second polarizing element 907 and a quarter wavelength plate as necessary. For example, the touch panel 909 is disposed on the viewing side of the touch panel element, the first quarter wavelength plate disposed on the viewing side of the touch panel element, and the first quarter wavelength plate. The second polarizing element 907 and a second quarter-wave plate disposed on the viewing side of the second polarizing element 907 may be provided. Such a touch panel is described in, for example, Japanese Patent Laid-Open No. 10-48625.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

Example 1
As shown in FIG. 4, a retardation film 401 having an in-plane retardation at a wavelength of 550 nm of 275 nm and Nz = 0.5 is formed on the surface of the liquid crystal panel 405 in which the transmission axis 404 of the viewing side polarizing plate 403 is perpendicular to the display surface. Then, the polarizing plate transmission axis 404 and the in-plane slow axis 402 of the retardation film were bonded via an adhesive layer so as to produce an in-vehicle display device. The liquid crystal panel with the above configuration is held on the backlight, placed in the center of the in-vehicle instrument panel, and the reflection on the windshield from various driver viewpoints has been confirmed. Was confirmed. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 2)
A retardation film is bonded to a liquid crystal panel in the same manner as in Example 1 except that the transmission axis of the polarizing plate and the in-plane slow axis of the retardation film are parallel to each other. As a result of the evaluation by various methods, it was confirmed that the effect of preventing reflection was sufficient from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 3)
As shown in FIG. 5, the first positive C plate in which the transmission axis 504 of the viewing side polarizing plate 503 is perpendicular to the display surface and the out-of-plane retardation in the thickness direction at a wavelength of 550 nm is −100 nm. A retardation film 507 and a second retardation film 501 of a positive A plate having an in-plane retardation of 137.5 nm at a wavelength of 550 nm were laminated and bonded in this order via an adhesive layer. Under the present circumstances, it bonded so that the in-plane slow axis 502 and polarizing plate transmission axis 504 of a 2nd phase difference film might become perpendicular | vertical. In addition, the in-plane slow axis 506 of the first retardation film faces the normal line direction with respect to the display surface. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

Example 4
(I) A positive A plate having an in-plane retardation of 137.5 nm at a wavelength of 550 nm is used as the first retardation film, and (ii) an out-of-plane retardation in the thickness direction at a wavelength of 550 nm is −100 nm as the second retardation film. And (iii) in the same manner as in Example 3, except that the in-plane slow axis of the first retardation film and the polarizing plate transmission axis are arranged in parallel. On the liquid crystal panel surface, the first retardation film and the second retardation film were laminated and bonded in this order via an adhesive layer. In addition, the in-plane slow axis of the second retardation film faces the normal line direction with respect to the display surface. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 5)
As shown in FIG. 6, the first retardation film 607 of the negative A plate in which the in-plane retardation at the wavelength of 550 nm is 145 nm on the surface of the liquid crystal panel 605 where the transmission axis 604 of the viewing side polarizing plate 603 is perpendicular to the display surface. And the 2nd phase difference film 601 of the negative C plate whose out-of-plane retardation of thickness direction in wavelength 550nm is 87 nm was laminated | stacked in this order through the adhesion layer. Under the present circumstances, it bonded so that the in-plane slow axis 606 and polarizing plate transmission axis 604 of the laminated | stacked 1st phase difference film might become parallel. In addition, the in-plane slow axis of the second retardation film faces the normal line direction with respect to the display surface. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 6)
(I) A negative C plate having an out-of-plane retardation in the thickness direction at a wavelength of 550 nm of 87 nm is used as the first retardation film, and (ii) a negative in-plane retardation at the wavelength of 550 nm is 145 nm as the second retardation film. A liquid crystal panel surface was obtained in the same manner as in Example 5 except that the A plate was used and (iii) the in-plane slow axis of the second retardation film and the polarizing plate transmission axis were perpendicular to each other. In addition, the first retardation film and the second retardation film were laminated and bonded in this order via an adhesive layer. In addition, the in-plane slow axis of the first retardation film faces the normal line direction with respect to the display surface. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 7)
As shown in FIG. 7, on the surface of the liquid crystal panel 705 where the transmission axis 704 of the viewing side polarizing plate 703 is perpendicular to the display surface, the in-plane retardation at a wavelength of 550 nm is 275 nm and Nz = 0.75. A film 707 and a second retardation film 701 having an in-plane retardation at a wavelength of 550 nm of 275 nm and Nz = 0.25 were laminated and laminated in this order via an adhesive layer. At this time, the in-plane slow axis 706 of the first retardation film and the in-plane slow axis 702 of the second retardation film are parallel, and the in-plane slow phases of the first and second retardation films are parallel. The axes 706 and 702 and the polarizing plate transmission axis 704 were bonded so as to be vertical. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint in light having a wider wavelength than that in Example 1. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 8)
(I) A retardation film having an in-plane retardation at a wavelength of 550 nm of 275 nm and Nz = 0.25 is used as the first retardation film, and (ii) an in-plane retardation at a wavelength of 550 nm is 275 nm as the second retardation film. (Iii) except that the in-plane slow axis and the polarizing plate transmission axis of the first and second retardation films are all parallel to each other. In the same manner as in Example 7, the first retardation film and the second retardation film were laminated and laminated in this order on the liquid crystal panel surface via an adhesive layer. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

Example 9
As shown in FIG. 4, a positive A plate retardation film 401 having an in-plane retardation of 275 nm at a wavelength of 550 nm is polarized on the surface of the liquid crystal panel 405 in which the transmission axis 404 of the viewing-side polarizing plate 403 is perpendicular to the display surface. The plate transmission axis 404 and the in-plane slow axis 402 of the retardation film 401 were bonded via an adhesive layer so as to be vertical. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 10)
The retardation film is bonded to the liquid crystal panel in the same manner as in Example 9 except that the transmission axis of the polarizing plate and the in-plane slow axis of the retardation film are parallel to each other. As a result of the evaluation by various methods, it was confirmed that the effect of preventing reflection was sufficient from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 11)
As shown in FIG. 9, the electrode surface of the glass substrate on which the ITO transparent electrode is vapor-deposited is regarded as a touch panel 903, and a polarization transmission axis 907 is formed on the display side surface with respect to the parallel direction of the display surface. Then, a polarizing plate 908 was bonded so as to be in the vertical direction, and a pseudo touch panel 909 having an antireflection structure was obtained. The pseudo touch panel 909 is installed on the surface of the liquid crystal panel 906 where the transmission axis 905 of the viewing side polarizing plate 904 is perpendicular to the display surface, the in-plane retardation at a wavelength of 550 nm is 275 nm, and Nz = 0.5. 901 was bonded through an adhesive layer so that the transmission axis 907 of the polarizing plate present on the viewing side of the pseudo touch panel 909 and the in-plane slow axis 902 of the retardation film were perpendicular to each other. When evaluated by the same method as in Example 1, a sufficient reflection suppression effect was confirmed from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Example 12)
The retardation film is bonded to the liquid crystal panel in the same manner as in Example 11, except that the transmission axis of the polarizing plate and the in-plane slow axis of the retardation film are arranged in parallel. As a result of the evaluation by various methods, it was confirmed that the effect of preventing reflection was sufficient from any viewpoint. Further, there was almost no decrease in transmittance when the display screen was directly viewed.

(Comparative Example 1)
As a comparative example, a display device in which the liquid crystal panel surface, whose transmission axis of the viewing-side polarizing plate is perpendicular to the display surface, is held on the backlight is placed in the center of the in-vehicle instrument panel, and the front is viewed from various driver viewpoints. When the reflection on the glass was confirmed, the driver position where the reflection suppression effect was obtained was limited, and the driving vision was hindered by the reflection on the windshield in a wide range.

(Comparative Example 2)
As a comparative example, LCF (manufactured by Sumitomo 3M) was installed on the surface of the liquid crystal panel in which the transmission axis of the viewing side polarizing plate was perpendicular to the display surface. Here, the LCF louver direction was set to be perpendicular to the transmission axis of the viewing side polarizing plate. A display device that holds the liquid crystal panel of this configuration on the backlight is placed in the center of the in-vehicle instrument panel, and reflection on the windshield has been confirmed from various driver viewpoints. However, when the display screen was directly viewed, a significant decrease in transmittance was observed, and moire was generated, which adversely affected visual recognition.

  The in-vehicle display device of the present invention can suppress the reflection on the windshield in a wider range than before, and the display device can be used for various vehicles having windshields (roads such as automobiles, buses, and trucks). It can be usefully used in a vehicle (rail vehicle).

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings. However, various additions, modifications, or deletions can be made without departing from the spirit of the present invention, and these are also included in the present invention. It is included in the range.

101 reflective surface 102 incident light beam 103 vibration direction of P-polarized component in incident light (perpendicular to reflective surface)
104 Vibration direction of S-polarized light component in incident light (parallel to reflection surface)
105 Incident angle 106 Vibration direction of P-polarized component in reflected light 107 Vibration direction of S-polarized component in reflected light 108 Reflected light beam 109 Transmitted light beam 201, 301, 1001 Windshields 202, 302, 1002 Drivers 203, 303, 1003 In-vehicle display devices 204, 304 In-vehicle display device viewing side polarization axis direction 205, 305 Polarization direction 206, 306 of incident light reflected toward the center of the vehicle Polarization direction 207,307 of incident light reflected toward the driver P-polarized axial direction 208,308 of light reflected toward the driver P-polarized axial direction 209,309 of light reflected toward the driver direction Incident light 210,310 from vehicle-mounted display device reflected toward the center of the car Reflected rays 211, 311, 1011 to the windshield incident light 212, 312, 1012 reflected toward the driver Reflected light rays 313, 401, 801, 901 in the direction of the user In-plane slow axis direction 403, 503, 603, 703, 803, 903 of the retardation film Polarizing film 404 on the surface of the liquid crystal panel, 504, 604, 704, 804, 904 Polarization transmission axis directions of polarizing plates on the liquid crystal panel surface 405, 505, 605, 705, 805, 905 Liquid crystal panel 501, 601, 701 Second retardation film 502, 602, 702 First Optical axis direction 506 of the second retardation film Optical axis direction 507, 607, 707 of the first retardation film First retardation film 606, 706 In-plane slow axis direction 906 of the first retardation film Polarization transmission axis direction 907 of the polarizing element Second polarizing element 908 Touch panel elements 809 and 909

Claims (8)

An in-vehicle display device that is disposed in a diagonally forward direction with respect to a viewer and has a display surface on the rear side that is the viewer's viewing side,
A liquid crystal panel that emits polarized light toward the viewing side;
At least one retardation film disposed on the viewing side of the liquid crystal panel;
Comprising at least
The polarized light has a polarization axis in a substantially vertical direction on the display surface;
The retardation film is a vehicle-mounted display device that corrects the polarization direction of polarized light emitted from the polarizing element into a P-polarization direction with respect to a vehicle windshield.   The in-vehicle display device according to claim 1, wherein the retardation film has an Nz coefficient of 0.4 ≦ Nz ≦ 0.6.   The in-vehicle display device according to claim 1, wherein the retardation film has a structure in which a first retardation film that is a positive C plate and a second retardation film that is a positive A plate are laminated.   The in-vehicle display device according to claim 1, wherein the retardation film has a structure in which a first retardation film that is a negative A plate and a second retardation film that is a negative C plate are laminated.   2. The structure of claim 1, wherein the retardation film is formed by laminating a first retardation film having an Nz coefficient of Nz = 0.75 and a second retardation film having an Nz coefficient of Nz = 0.25. A vehicle-mounted display device.   The in-vehicle display device according to claim 1, wherein the retardation film is a half-wave plate of a positive A plate.   The on-vehicle display device according to claim 1, wherein an in-plane slow axis of at least one retardation film is parallel or perpendicular to a polarization transmission axis of the viewing side polarizing plate.   The in-vehicle display device according to claim 1, wherein the in-vehicle display device includes a touch panel between a liquid crystal panel and a retardation film.

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