JP2009086124A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of displaying a three-dimensional stereoscopic image with desired display luminance without requiring a strong light source. <P>SOLUTION: In the display device where two display panels 30 and 70 are arranged in a multilayered state, a lower polarizing plate 75 is arranged on the back of the upper panel 70 and also an upper polarizing plate 76 is arranged on the front thereof, then a lower polarizing plate 35 is arranged on the back of the lower panel 30. At that time, a polarizing plate is not arranged on the front of the lower panel 30. Thus, transmittance of an entire module is made high, and also cost is reduced as much as cost of one polarizing plate in comparison with a case where the polarizing plates are arranged on the upper and lower surfaces of the upper and lower panels, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device that includes a multilayer display panel and displays a three-dimensional stereoscopic image.

Conventionally, a three-dimensional display device that displays a three-dimensional stereoscopic image to an observer by arranging a plurality of display panels (for example, liquid crystal display panels) at different depth positions as viewed from the observer is known.
As such a three-dimensional display device, in order to prevent the occurrence of moire (interference fringes) due to the interference of pixel patterns of each display panel, a diffusion plate is arranged between a plurality of display panels. (For example, refer to Patent Document 1).

Further, in the three-dimensional display device, each display panel has a plurality of pixels, and at least one of the plurality of display panels is disposed on the side close to the observer, and a wall perpendicular to the surface of the display panel, It is also known that a diffusing plate disposed on the side closer to the observer is provided to prevent the occurrence of moiré without reducing the display resolution (see, for example, Patent Document 2).
Japanese Patent No. 3335998 Specification JP 2004-336290 A

  By the way, in the case of a display device using two display panels as in the conventional three-dimensional display device, light from the backlight (light source) passes through the two display panels. Further, it is common to attach polarizing plates to both surfaces of the display panel. In this case, light from the light source further passes through four polarizing plates, and the transmittance of the entire module is lowered. Therefore, in order to ensure a certain level of luminance on the module surface, it is necessary to increase the backlight light.

However, if the light from the backlight is strengthened, heat generation in the module increases, which may adversely affect the overheat protection of the polarizing plate and resin material parts.
Therefore, it is desired to obtain a desired display luminance without requiring a strong light source by increasing the transmittance of the module so as to transmit as much light as possible.
Therefore, an object of the present invention is to provide a display device that displays a three-dimensional stereoscopic image with a desired display luminance without requiring a strong light source.

In order to solve the above-described problem, a display device according to a first aspect of the present invention is a display device including a first display panel and a second display panel disposed on the back surface of the first display panel.
A first polarizing plate disposed in front of the first display panel;
A second polarizing plate disposed on the back surface of the second display panel;
And a third polarizing plate fixed in close contact with the back surface of the first display panel or fixed in close contact with the front surface of the second display panel.

Accordingly, the polarizing plate disposed between the first display panel and the second display panel is used as one sheet so that the transmittance of the entire module can be increased, and a strong backlight luminance is not required. The brightness can be ensured. Further, the cost for one polarizing plate can be reduced as compared with the case where polarizing plates are arranged on the upper and lower surfaces of each display panel.
According to a second invention, in the first invention, the third polarizing plate is fixed in close contact with the back surface of the first display panel, and a predetermined gap is provided between the third polarizing plate and the third polarizing plate. The second display panel is disposed at a distance.

Accordingly, it is possible to reliably prevent a region where the display cannot be seen when the user shakes his / her vision due to the gap between the first display panel and the second display panel. Can improve the appearance of the panel.
Furthermore, a third invention is the first or second invention, wherein a lighting device is provided on the back side of the second display panel, and the first display panel and the second display panel are stacked. Thus, a three-dimensional stereoscopic image is displayed.

  As a result, a three-dimensional stereoscopic image can be displayed with a desired display luminance without requiring a strong light source from the illumination device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view showing a liquid crystal module constituting the display device of this embodiment.
As shown in FIG. 1, the liquid crystal module 1 includes a backlight unit 100 and a panel unit 200.
The backlight unit 100 includes a back cover 10 and a backlight 20, and the panel unit 200 includes a lower panel 30, a lower case 40, a diffusion plate 50, an upper case 60, an upper panel 70, and a front panel. The cover 80 is composed of source substrates 90A and 90B. In the liquid crystal module 1, the front cover 80 side is the front surface and the back cover side is the back surface.

The upper panel 70 and the lower panel 30 are liquid crystal panels made of a transparent insulating material, for example, a glass substrate. These panels 70 and 30 are arranged so that two substrates are opposed to each other at a predetermined interval, Are bonded with a sealing material and liquid crystal is enclosed.
As described above, the display device according to the present embodiment has a stacked arrangement in which two liquid crystal panels are arranged at different depth positions as viewed from the observer. For example, the upper panel 70 displays a moving image of a vehicle, etc. By displaying a background image on the panel 30, a three-dimensional stereoscopic image can be displayed.

The back cover 10 is made of, for example, a metal plate, and has four side walls that define a fixed storage space in which the backlight 20 and the panel unit 200 excluding the front cover 80 can be stored.
The backlight 20 includes a well-known light source, a reflection sheet, and a light guide plate (not shown). Light from the light source is incident on the light guide plate, and the light guide plate emits the light toward the panel unit 200 which is the surface of the light guide plate. Further, the reflection sheet is disposed on the back surface of the light guide plate so that light incident from the light guide plate incident surface does not exit from a surface other than the light guide plate surface.

FIG. 2 is a perspective view showing a schematic configuration of the lower panel 30 and the upper panel 70.
As described above, the lower panel 30 and the upper panel 70 are each composed of two upper and lower substrates and a liquid crystal layer (not shown) filled therebetween. In FIG. 2, reference numeral 34 a is the upper substrate of the lower panel 30, reference numeral 34 b is the lower substrate of the lower panel 30, reference numeral 74 a is the upper substrate of the upper panel 70, and reference numeral 74 b is the lower substrate of the upper panel 70.

  Of the upper and lower substrates 74a and 74b of the upper panel 70, a part of the lower substrate 74b protrudes from the upper substrate 74a, and a driver IC 71 for driving is mounted on the protruding portion. As shown in FIG. 1, the upper panel 70 and the source substrate 90A are connected via a flexible printed circuit board (hereinafter referred to as FPC) 72, and the drive driver IC 71 is driven by the FPC 72 from the source substrate 90A. A signal is supplied.

Here, the connecting portion between the FPC 72 and the source substrate 90A and the connecting portion between the FPC 72 and the upper panel 70 are connected by pressure contact, pressure bonding, or connector connection, respectively.
As shown in FIG. 1, the upper case 60 includes a frame-shaped frame portion 61 having a through hole formed in the center, and one side of the frame portion 61 (the upper side of the frame portion 61 in FIG. 1). The substrate receiving portion 62 extends in the thickness direction and supports the source substrate 90A, and the source substrate 90A is bent to the substrate receiving portion 62 of the upper case 60 by bending the FPC 72 at a substantially right angle when assembled. .

Further, an upper polarizing plate 76 and a lower polarizing plate 75 are attached to the upper and lower surfaces of the upper panel 70 (fixed in close contact).
Similarly, of the upper and lower substrates 34a and 34b of the lower panel 30, a part of the lower substrate 34b protrudes from the upper substrate 34a, and a driver IC 31 for driving is mounted on the protruding portion. As shown in FIG. 1, the lower panel 30 and the source substrate 90B are connected via a flexible printed circuit board (hereinafter referred to as FPC) 32, and the drive driver IC 31 is driven by the FPC 32 from the source substrate 90B. A signal is supplied.

Here, the connecting portion between the FPC 32 and the source substrate 90B and the connecting portion between the FPC 32 and the lower panel 30 are connected by pressure contact, pressure bonding, or connector connection, respectively. The source substrate 90B is screwed to the substrate receiving portion 22 which is the side surface of the backlight 20 by bending the FPC 32 at a substantially right angle when assembled.
A lower polarizing plate 35 is attached to the lower surface of the lower panel 30 (the back surface of the lower panel 30).

With such a configuration, the light emitted from the backlight 20 is incident on the back surface of the lower panel 30, passes through the lower polarizing plate 35, and is emitted from the front surface of the lower panel 30. Then, the light is incident on the back surface of the upper panel 70, passes through the lower polarizing plate 75 and the upper polarizing plate 76, and is emitted from the front surface of the upper panel 70.
Here, the transmission axes of the lower polarizing plate 75 and the upper polarizing plate 76 are each set to 135 degrees, and the transmission axes of the lower polarizing film 35 are shifted by 90 degrees from the transmission axes of the lower polarizing film 75 and the upper polarizing film 76. It is assumed that the angle is set to 45 degrees.

Returning to FIG. 1, a frame-shaped lower case 40 having a through hole formed in the center is disposed on the front surface of the lower panel 30, and the diffusion plate 50 is supported by the lower case 40. An upper case 60 is disposed on the front surface of the diffusion plate 50, and the upper panel 70 is supported by the upper case 60. Here, it is assumed that the lower case 40 and the upper case 60 are made of, for example, a resin material.
The diffusion plate 50 is disposed between the upper panel 70 and the lower panel 30 with a predetermined distance from both panels.

That is, a predetermined interval (for example, about 2 mm) is secured between the lower panel 30 and the diffusion plate 50 depending on the thickness of the lower case 40 disposed on the front surface of the lower panel 30, and is disposed on the front surface of the lower case 40. Depending on the thickness of the frame portion 61 of the upper case 60, a predetermined distance (for example, about 17 mm) is secured between the upper panel 70 and the diffusion plate 50.
As described above, by arranging the diffusion plate 50 between the upper panel 70 and the lower panel 30, it is possible to prevent the pixel patterns of the upper panel 70 and the lower panel 30 from interfering with each other to generate moire (interference fringes). is doing. The predetermined interval is set so that the diffusing plate 50 is disposed at a position where moire disappears properly.

  When assembling the liquid crystal module 1 having such a configuration, first, the lower panel 30, the lower case 40, the diffusion plate 50, the upper case 60, and the upper panel 70 are stacked in this order from the front surface of the backlight 20. Thereafter, the back cover 10 is covered from the back side, the front cover 80 is covered from the front side, and the liquid crystal module 1 is completed by fixing with a fastening member 81 such as a screw.

In FIG. 1, the upper panel 70 corresponds to the first display panel, the lower panel 30 corresponds to the second display panel, the upper polarizing plate 76 corresponds to the first polarizing plate, and the lower polarizing plate 35. Corresponds to the second polarizing plate, the lower polarizing plate 75 corresponds to the third polarizing plate, and the backlight 20 corresponds to the lighting device.
FIG. 3 is a schematic configuration diagram when polarizing plates are attached to the upper and lower surfaces of two display panels.

In the lower panel 1030, a lower polarizing plate 1035 is disposed on the back surface of the substrate 1034, and an upper polarizing plate 1036 is disposed on the front surface of the substrate 1034. In the upper panel 1070, the lower polarizing plate 1075 is disposed on the back surface of the substrate 1074, and the upper polarizing plate 1076 is disposed on the front surface of the substrate 1074.
In this case, light from a light source (not shown) enters the back surface of the lower panel 1030, passes through the lower polarizing plate 035 and the upper polarizing plate 1036, and exits from the front surface of the lower panel 1030. Then, the light is incident on the back surface of the upper panel 1070, passes through the lower polarizing plate 1075 and the upper polarizing plate 1076, and is emitted from the front surface of the upper panel 1070.

At this time, the transmission axes of the lower polarizing plate 1035 and the upper polarizing plate 1076 are each set to 135 degrees, and the transmission axes of the upper polarizing plate 1036 and the lower polarizing film 1075 are respectively set to 45 degrees.
Thus, the angles of the transmission axes of the polarizing plates 1075 and 1036 disposed between the lower panel 1030 and the upper panel 1070 are equal, and the actions of these polarizing plates 1075 and 1036 are equal.

By the way, in the display device using two display panels, when a polarizing plate is attached to the upper and lower surfaces of each display panel as shown in FIG. 1075, 1076, 1035, 1036), the transmittance as a whole becomes low and the display surface becomes dark.
Therefore, in order to obtain a desired display luminance, it is conceivable to increase the backlight luminance as a light source. However, in this case, heat generation in the module is increased, which adversely affects overheating protection of polarizing plate and resin material parts. May cause effects.

Therefore, it is desired to obtain a desired display luminance without increasing the backlight luminance.
As is clear from FIG. 3, the two polarizing plates 1075 and 1036 between the upper panel 1070 and the lower panel 1030 have the same transmission axis and the same function. Therefore, there is no theoretical problem even if one of the two polarizing plates 1075 and 1036 is deleted.

However, when the diffusion plate 50 is disposed between the lower panel 30 and the upper panel 70 at a predetermined interval from each other as in the present embodiment, the distance between the lower panel 30 and the upper panel 70 is relatively small. Widen (for example, about 19 mm).
As described above, when the distance between the two display panels is relatively wide, if the lower polarizing plate 1075 is deleted from the two polarizing plates 1075 and 1036 described above, the display can be seen on the display surface when the user visually shakes. An area that disappears (non-display area) occurs.

FIG. 4 is a diagram illustrating a non-display area generated when the user shakes his / her vision.
When the space α is provided between the lower panel 1030 and the upper panel 1070, the edge of the lower panel 1030 is positioned inside the display surface when the user shakes his / her vision (when the viewing angle is smaller than 90 degrees). become. At this time, even if the upper polarizing plate 1036 is attached to the front surface of the lower panel 1030, the hatched region in FIG. 4 is a region that cannot be covered by the upper polarizing plate 1036, and this is a non-display region.

This phenomenon becomes more prominent as the distance α between the lower panel 1030 and the upper panel 1070 is wider. As described above, when a predetermined interval is provided between the lower panel 1030 and the upper panel 1070, it is impossible to remove the lower polarizing plate 1075 on the back surface of the upper panel 1070 as a product.
Therefore, in this embodiment, the polarizing plate on the front surface of the lower panel 30 is deleted, and only the lower polarizing plate 75 attached to the back surface of the upper panel 70 is disposed between the lower panel 30 and the upper panel 70. The configuration is as follows. As a result, it is possible to reliably prevent a non-display area from being generated when the user shakes his / her vision, and to increase the transmittance of the entire module as compared to the case where polarizing plates are arranged on the upper and lower surfaces of the upper and lower panels, respectively. be able to.

  As described above, in the above embodiment, any one of the first polarizing plate disposed on the front surface of the upper panel, the second polarizing plate disposed on the back surface of the lower panel, the rear surface of the upper panel, and the front surface of the lower panel. Since the third polarizing plate is arranged on either side, the polarizing plate arranged between the upper panel and the lower panel can be made one, and the transmittance of the entire module is increased and displayed. Brightness can be increased. As a result, it is possible to obtain a desired display luminance without requiring a strong light source, thereby suppressing the heat generation of the module caused by increasing the luminance of the light source and realizing overheating protection of the components.

In addition, since one polarizing plate is arranged between the upper panel and the lower panel, the cost for one polarizing plate can be reduced compared to the case where polarizing plates are arranged on the upper and lower surfaces of each display panel. Can be realized.
Furthermore, since the upper panel and the lower panel are arranged with a predetermined interval and the third polarizing plate is arranged on the back surface of the upper panel, it is ensured that an area where the display cannot be seen is generated when the user visually shakes. Therefore, the appearance of the panel can be improved.

  In addition, the upper panel and the lower panel having such a configuration are stacked and provided with a backlight on the back side of the lower panel, so that a three-dimensional stereoscopic image can be displayed with a desired display luminance without requiring a strong backlight luminance. Can be a display device.

It is a disassembled perspective view which shows the liquid crystal module of embodiment in this invention. It is a perspective view which shows schematic structure of a panel. It is a schematic block diagram at the time of sticking a polarizing plate on the upper and lower surfaces of a display panel. It is a figure which shows a non-display area | region.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal module, 10 ... Back cover, 20 ... Back light, 22 ... Board | substrate receiving part, 30 ... Lower panel, 31 ... Driver IC for drive, 32 ... FPC, 35 ... Lower polarizing plate, 36 ... Upper polarizing plate, 40 ... lower case, 50 ... diffusion plate, 60 ... upper case, 61 ... frame part, 62 ... substrate receiving part, 70 ... upper panel, 71 ... driver IC for driving, 72 ... FPC, 75 ... lower polarizing plate, 80 ... front Cover, 90A, 90B ... source substrate, 100 ... backlight unit, 200 ... panel unit

Claims (3)

In a display device comprising a first display panel and a second display panel disposed on the back surface of the first display panel,
A first polarizing plate disposed in front of the first display panel;
A second polarizing plate disposed on the back surface of the second display panel;
And a third polarizing plate fixed in close contact with the back surface of the first display panel or fixed in close contact with the front surface of the second display panel.   The third polarizing plate is fixed in close contact with the back surface of the first display panel, and the second display panel is disposed with a predetermined gap from the third polarizing plate. The display device according to claim 1.   The lighting device is provided on the back side of the second display panel, and the first display panel and the second display panel are stacked to display a three-dimensional stereoscopic image. Or the display apparatus of 2.

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