JP2005292753A - Display device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need for an extra control circuit, to switch between normal display and a mirror state through easy operation, and to display specified information on a display screen even when the display surface is made to function as a mirror. <P>SOLUTION: This display device is equipped with an image display part 1 which displays an image, an absorption type polarizing means 14 which is arranged on an observation side of the image display part 1, and a reflection type polarizing means 20 which is arranged on an observation side of the absorption type polarizing means 14; and the reflection type polarizing means 20 transmits 1st polarized light parallel to an axis of transmission and reflects 2nd polarized light crossing the axis of the transmission, which is variable in angle in plane to the axis of transmission of the absorption type polarizing means 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device and an electronic apparatus.

In mobile phones, PDAs, and the like, there are considered applications in which the display screen is switched between a normal screen and a mirror as an accessory during standby.
As such a display device, a half mirror is arranged on the observation side, a normal transmissive display is obtained when the backlight is turned on, and only the external light reflected by the half mirror is seen when the backlight is turned off. Is known (for example, see Patent Document 1).
In addition, a reflective polarizing plate is provided outside the absorption polarizing plate on the observation side, and the transmission axis of the reflective polarizing plate is arranged so as to be parallel to the absorbing polarizing plate. It is known that a transmissive display is obtained, and when the backlight is turned off, a mirror state in which only external light reflected by the reflective polarizing plate can be seen.
Japanese Patent Laid-Open No. 11-15392

However, in the above prior art, the normal display and the mirror state are performed by turning the backlight on and off, so that a separate control circuit is required and a button operation by the user is required.
In addition, since the backlight is turned off and the mirror state is set, the display surface is in a full mirror state in the mirror state, and it is not possible to recognize even useful information to be displayed on the display device such as time and date. Arise.

  The present invention was devised in view of the above-described problems, and does not require a separate control circuit, can switch between normal display and mirror state by an easy operation, and when the display surface functions as a mirror. It is another object of the present invention to provide a display device and an electronic apparatus that can display predetermined information on a display surface.

  In order to achieve the above object, a display device of the present invention includes an image display unit that displays an image, an absorption polarization unit disposed on the observation side of the image display unit, and an observation side of the absorption polarization unit. A reflective polarizing means disposed, the reflective polarizing means transmits a first polarized light parallel to a transmission axis and reflects a second polarized light intersecting the transmission axis, and the transmission axis is The angle in the plane with respect to the transmission axis of the absorptive polarization means is variable.

According to this configuration, the normal display for displaying the image from the image display unit and the mirror state can be switched by changing the angle of the transmission axis of the reflective polarization unit with respect to the transmission axis of the absorption polarization unit. it can. That is, it is possible to switch between the normal display and the mirror state by an extremely easy operation without incorporating a separate control circuit as compared with the case where the backlight is turned ON / OFF.
In addition, by setting the transmission axis of the reflective polarizing means to an intermediate angle between parallel and orthogonal to the transmission axis of the absorbing polarizing means, the image light from the image display unit is displayed on the display surface while being mirrored. A state can also be generated.

The reflective polarizing means may be rotatable in a plane with respect to the absorbing polarizing means.
According to this configuration, it is possible to switch between the normal display for displaying an image from the image display unit and the mirror state very easily by simply rotating the reflective polarizing means.

Further, it is preferable that the reflective polarizing means is provided so as to overlap a part of the image display unit in a plane.
According to this configuration, for example, while displaying useful information such as date and time, a part of the display surface can function as a mirror, and usability can be improved.
The image display unit may be configured as a liquid crystal display device.

In addition, an electronic apparatus according to the present invention includes the above-described display device.
According to this configuration, the normal display and the mirror state can be switched by an extremely easy operation. Further, the mirror state can be generated while displaying the image light from the image display unit on the display surface.

  The electronic apparatus of the present invention includes an image display unit that displays an image, an absorption polarization unit disposed on the observation side of the image display unit, and a reflective polarization unit disposed on the observation side of the absorption polarization unit. And a rotation operation unit that relatively rotates the absorption-type polarization unit and the reflection-type polarization unit in a plane, and the reflection-type polarization unit includes a first parallel to the transmission axis. Transmits the polarized light and reflects the second polarized light that intersects the transmission axis, and the rotation operation unit is an angle in a plane between the transmission axis of the reflection-type changing means and the transmission axis of the absorption-type polarization means. It is characterized by changing.

According to this configuration, the absorption type polarization unit and the reflection type polarization unit are relatively rotated in a plane by the rotation operation unit, and therefore, the reflection type polarization unit of the reflection type polarization unit with respect to the transmission axis of the absorption type polarization unit. The angle of the transmission axis can be changed, and the normal display for displaying the image from the image display unit and the mirror state can be switched. That is, it is possible to switch between the normal display and the mirror state by an extremely easy operation without incorporating a separate control circuit as compared with the case where the backlight is turned ON / OFF.
Further, by operating the rotation operation unit, the transmission axis of the reflective polarization unit is set to an intermediate angle between parallel and orthogonal to the transmission axis of the absorption polarization unit, thereby preventing the image display unit from It is also possible to cause a mirror state while displaying image light on the display surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a schematic configuration of a display device as an embodiment of the present invention, and FIG. 2 is a diagram showing only components necessary for explaining the display principle in order to explain the display principle. 3 and 4 are diagrams each illustrating an example of an electronic apparatus including the display device. In all the drawings below, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.

  As shown in FIG. 1, in the display device according to the present embodiment, a liquid crystal cell 10 having a backlight 50 disposed on the back surface and a reflective polarizing plate (reflective polarizing means) 20 are sequentially arranged toward the display surface side. Has been configured. In this specification, the surface on the liquid crystal side of each substrate constituting the liquid crystal cell 10 is referred to as an “inner surface”, and the opposite surface is referred to as an “outer surface”. In the present display device, the reflective polarizing plate 20 side is a display surface for observing image light or the like.

  The liquid crystal cell 10 is an active matrix type liquid crystal display device in which a lower substrate 11 and an upper substrate 12 are arranged to face each other, and a dielectric anisotropy is positive in a space between the upper substrate 12 and the lower substrate 11. The TN liquid crystal is sealed to form a liquid crystal layer 19. A backlight 50 is disposed on the rear surface side of the liquid crystal cell 10 (the outer surface side of the lower substrate 11). The liquid crystal cell 10 and the backlight 50 constitute the image display unit 1.

  A pixel electrode 15 made of a transparent conductive film such as ITO (Indium Tin Oxide) is formed on the inner surface side of the lower substrate 11 made of a light-transmitting material such as glass or plastic, and polyimide or the like is used to cover the pixel electrode 15 An alignment film 17 is laminated. In the present embodiment, the lower substrate 11 is composed of an element substrate on which pixel switching elements such as TFTs, data lines, and scanning lines are formed. In FIG. 1, the pixel switching elements, data lines, and scanning lines are formed. Such illustration is omitted. A lower absorption polarizing plate 13 is provided on the outer surface side of the lower substrate 11.

On the other hand, a common electrode 16 made of a transparent conductive film such as ITO and an alignment film 18 made of polyimide or the like are sequentially laminated on the inner surface side of the upper substrate 12 made of a translucent material such as glass or plastic. Further, an upper polarizing plate (absorption type polarizing means) 14 is provided on the outer surface side of the upper substrate 12. Although not shown, a color filter having R (red), G (green), and B (blue) pigment layers is provided on the inner surface side of the upper substrate 12.
Both the alignment films 18 and 17 on the upper substrate 12 side and the lower substrate 11 side are subjected to a horizontal alignment process such as a rubbing process, and the alignment directions of the alignment films 18 and 17 are orthogonal to each other. Therefore, the liquid crystal molecules of the liquid crystal layer 19 are twisted by approximately 90 ° in a plane parallel to the substrate surface between the upper substrate 12 and the lower substrate 11 when a non-selection voltage is applied (voltage off).

Further, the transmission axis direction of the upper absorption polarizing plate 14 and the transmission axis direction of the lower absorption polarizing plate 13 are both set in the same direction. That is, the transmission axis direction of the lower absorption polarizing plate 13 and the alignment direction of the liquid crystal molecules in contact with the inner surface of the substrate 11 are substantially perpendicular, and the liquid crystal molecules in contact with the transmission axis direction of the upper absorption polarizing plate 14 and the inner surface of the substrate 12. Is substantially parallel to the orientation direction.
The backlight 50 includes a light source 51, a reflection plate 52, and a light guide plate 53, and light transmitted through the light guide plate 53 is transmitted to the lower surface side (the side opposite to the liquid crystal cell 10) of the light guide plate 53. A reflecting plate 54 for emitting light toward the 10 side is provided.

The reflective polarizing plate 20 is a deflecting plate that has the property of transmitting linearly polarized light (first polarized light) parallel to the transmission axis and reflecting linearly polarized light (second polarized light) orthogonal to the transmission axis. A reflective polarizing film such as DBEF is used.
The reflective polarizing plate 20 is rotatable with respect to the upper absorption polarizing plate 14 of the liquid crystal cell 10. The angle of the transmission axis of the reflection type polarizing plate 20 can be changed with respect to the transmission axis of the upper absorption type polarizing plate 14 of the liquid crystal cell 10 by rotating the reflection type polarizing plate 20. ing.

Hereinafter, the display principle of the display device of this embodiment will be described with reference to FIG.
First, when performing normal display, the transmission axis of the reflective polarizing plate 20 is made parallel to the transmission axis of the upper absorption polarizing plate 14 of the liquid crystal cell 10 as shown on the left side of FIG.
In this case, the image light emitted from the liquid crystal cell 10 passes through the reflective polarizing plate 20 as it is and is displayed on the display surface.
On the other hand, light having a polarization axis parallel to the transmission axis of the reflective polarizing plate 20 out of the external light incident from above the reflective polarizing plate 20 is transmitted through the liquid crystal cell 10 and reflected by the reflective layer 54 of the backlight 50. Is done. As described above, the external light reflected by the reflective layer 54 is substantially the same as the illumination light, and thus becomes a part of the illumination light and does not reflect the external light that deteriorates the image quality. In addition, light having a polarization axis perpendicular to the transmission axis of the reflective polarizing plate 20 among the external light incident from above the reflective polarizing plate 20 is reflected by the surface of the reflective polarizing plate 20, but the backlight 50 If the brightness is sufficient, the display surface is canceled and the display surface functions as an image display surface.

Next, when performing mirror display, as shown on the right side of FIG. 2, the reflection type polarizing plate 20 is rotated so that its transmission axis is orthogonal to the transmission axis of the upper absorption type polarizing plate 14 of the liquid crystal cell 10. .
In this case, the image light emitted from the liquid crystal cell 10 is not reflected by the reflective polarizing plate 20 and displayed on the display surface.
On the other hand, light having a polarization axis perpendicular to the transmission axis of the reflection type polarizing plate 20 out of the external light incident from above the reflection type polarizing plate 20 is reflected by the reflection type polarizing plate 20 to display a mirror-like display. Present. Note that light having a polarization axis parallel to the transmission axis of the reflection type polarizing plate 20 among the external light incident from above the reflection type polarizing plate 20 is absorbed by the absorption type polarizing plate 14 after passing through the reflection type polarizing plate 20. Therefore, the display is not affected.

  As described above, according to the display device of this embodiment, the angle of the transmission axis of the reflective polarizing plate 20 with respect to the transmission axis of the upper absorption polarizing plate 14 of the liquid crystal cell 10 is changed to change between the normal display and the mirror state. Can be switched. That is, it is possible to switch between the normal display and the mirror state by an extremely easy operation without incorporating a separate control circuit as compared with the case where the backlight is turned ON / OFF.

  Further, by setting the transmission axis of the reflective polarizing plate 20 to an intermediate angle between parallel and orthogonal to the transmission axis of the upper absorption polarizing plate 14 of the liquid crystal cell 10, the image light from the liquid crystal cell 10 can be reduced. A mirror state can be generated while displaying on the display surface. The ratio of the display degree at this time can be freely adjusted by the angle of the transmission axis of the reflective polarizing plate 20 with respect to the transmission axis of the absorption polarizing plate 14.

[Electronics]
An example of an electronic apparatus including the display device of the above embodiment will be described.
FIG. 3 is a cross-sectional view illustrating an example of a mobile phone, and FIG. 4 is a perspective view illustrating an operation on the mobile phone of the example. 3 and 4, reference numeral 1000 indicates a mobile phone body, and reference numeral 1001 indicates a display unit using the display device of the above embodiment.
As shown in the drawing, the reflective polarizing plate 20 of the display device constituting the display unit 1001 of the cellular phone is rotatably provided. In addition, a lever (rotating operation unit) 1002 is attached to the reflective polarizing plate 20, and the lever 1002 protrudes outside from a slit 1004 formed on the side surface of the case 1003. Note that the slit 1004 is formed over about 90 ° from the top of the case 1003 to one side in plan view.

  According to this mobile phone, as shown in FIG. 4, it is extremely easy to hold the lever 1002 and move it in the slit 1004 to rotate the reflective polarizing plate 20 within a range of about 90 °. The display unit 1001 can be switched between the normal display and the mirror state. In addition, by operating the lever 1002 to adjust the rotation angle of the reflective polarizing plate 20, it can be in a mirror state while displaying an image.

In the above example, the reflective polarizing plate 20 itself is configured to rotate. For example, a cover glass is rotatably provided on the display unit 1001, and the reflective polarizing plate 20 is attached to the cover glass. Also good.
Further, although the reflective polarizing plate 20 is manually rotated, the reflective polarizing plate 20 may be electrically rotated.
The display device of this embodiment can also be applied to electronic devices such as toys that include a display unit.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
Here, in the above-described embodiment, the reflective polarizing plate 20 is provided on the entire surface. However, the reflective polarizing plate 20 may be provided on a part of the surface. In addition, while displaying useful information such as date and time at all times, a part of the display surface can function as a mirror, and usability can be improved.

  Further, the liquid crystal cell 10 constituting the image display unit 1 as in the above embodiment is not limited to an active matrix type liquid crystal display device capable of color display, but a passive type liquid crystal display device such as a passive matrix type or a dot matrix type, It is also possible to apply a monochrome display liquid crystal display device. Further, the image display unit 1 may be configured by an organic EL device instead of the liquid crystal cell 10 and the backlight 50. In this case, an absorption type polarizing plate is arranged between the organic EL device and the reflection type polarizing plate 20, and the angle of the transmission axis of the reflection type polarizing plate 20 is changed with respect to the transmission axis of the absorption type polarizing plate. You can do it.

1 is a cross-sectional view illustrating a schematic configuration of a display device as an embodiment of the present invention. The figure for demonstrating the display principle of a display apparatus similarly. FIG. 14 is a cross-sectional view illustrating an example of an electronic device according to the invention. FIG. 11 is a perspective view illustrating an example of an electronic apparatus according to the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image display part, 14 ... Upper absorption type polarizing plate (absorption type polarizing means), 20 ... Reflective type polarizing plate (reflection type polarizing means), 1000 ... Mobile-phone main body (electronic device), 1002 ... Lever (rotation operation) Part).

Claims (6)

An image display section for displaying an image;
An absorptive polarizing means disposed on the observation side of the image display unit;
A reflective polarizing means disposed on the observation side of the absorbing polarizing means,
The reflective polarization means transmits the first polarized light parallel to the transmission axis and reflects the second polarized light intersecting the transmission axis,
The display device according to claim 1, wherein an angle of the transmission axis in a plane with respect to the transmission axis of the absorptive polarizing means is variable.   The display device according to claim 1, wherein the reflective polarization unit is rotatable in a plane with respect to the absorption polarization unit.   The display device according to claim 1, wherein the reflective polarization unit is provided so as to overlap with a part of the image display unit.   The display device according to claim 1, wherein the image display unit is a liquid crystal display device.   An electronic apparatus comprising the display device according to claim 1. An image display section for displaying an image;
An absorptive polarizing means disposed on the observation side of the image display unit;
Reflective polarizing means disposed on the viewing side of the absorbing polarizing means;
A rotation operation unit that relatively rotates the absorption polarization unit and the reflection polarization unit in a plane;
Comprising
The reflective polarization means transmits the first polarized light parallel to the transmission axis and reflects the second polarized light intersecting the transmission axis,
The electronic device according to claim 1, wherein the rotation operation unit changes an angle in a plane between a transmission axis of the reflection type changing unit and a transmission axis of the absorption type polarizing unit.

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