The present invention relates to a display device, being capable of displaying different content in different viewing angles and comprising an LCD panel and a backlighting arrangement.
Such a device is disclosed e.g. in WO, 2004/088996, A1. This device is intended to be used as an autostereoscopic 3D display and comprises an LCD panel and a switchable backlighting arrangement, which is capable of providing backlight with two different angular distributions, one being suitable for displaying content to the right eye of a user, and another being suitable for displaying to the user's left eye. The backlight is switched between the two states, and at the same time the LCD panel is switched between showing right eye and left eye content.
A disadvantage with such a display is the high speed requirements imposed on the LCD panel in order to achieve flicker-free displaying of information. These requirements result in a complex and expensive display.
An object of the present invention is therefore to provide a less complex and thus less expensive solution.
This object is achieved by means of display device as defined in claim 1. More specifically, the device then comprises an LCD panel and a backlighting arrangement, wherein a first subsection of the LCD panel is arranged to display a first image and a second subsection of the LCD panel is arranged to display a second image, and the backlighting arrangement, at said first subsection, is arranged to emit light with a first angular distribution, and, at the second subsection, is arranged to emit light with a second angular distribution which is different from the first angular distribution. This means that the content displayed on the LCD panel need not be rapidly switched between information intended to be displayed e.g. to the left and to the right. LCD panel requirement can therefore be kept low as can the display device cost.
In a preferred embodiment, the backlighting arrangement comprises a lightguide, arranged to selectively emit light with the first or second angular distribution, a first controllable shutter, covering the first LCD panel sub-section and a second controllable shutter, covering the second LCD panel sub-section, and is arranged to emit, in a first mode, light with the first angular distribution while making the first shutter transmissive and the second shutter blocking, and, in a second mode, light with the second angular distribution while making the first shutter blocking and the second shutter transmissive. This is one low-cost implementation of the inventive idea. The shutters may have coarse pixels, and need only switch between being fully blocking and fully transmitting, and may therefore be accomplished at low cost.
The first angular distribution may be emitted by activating a first lamp and light with the second angular distribution may be emitted by activating a second lamp.
The backlighting arrangement may also emit, in a third mode, light with both angular distributions simultaneously, while making both shutters transmissive. The display may then also be operated without a dual view function, i.e. without displaying different content in different directions.
The backlighting arrangement may also be arranged to selectively emit light with a third angular distribution. This allows e.g. in a vehicle the adaptation of the display to different seating positions of a passenger.
In an alternative embodiment, the backlighting arrangement may comprise a lightguide, arranged to emit light with the second angular distribution, and a first diffuser, which covers the first LCD panel sub-section and changes the angular distribution at that sub-section into the first angular distribution. A diffuser performing this function may also be accomplished at low cost, and may also be controllable.
In the alternative embodiment, the backlighting arrangement may also comprise a second controllable diffuser, covering the second LCD panel sub-section.
The LCD panel may have the format 16:9 and the second sub-section the format 4:3, such that the division between the first and second sub-sections is accomplished by a vertical border.
Alternatively, the LCD panel may have the format 4:3, and the second sub-section the format 16:9, such that the division between the first and second sub-sections is accomplished by a horizontal border.
The display device may be mounted in a vehicle, the first image being intended for the vehicle driver, and the second image being intended for a vehicle passenger.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.
In prior art devices this has been addressed by providing a display device that displays the driver information in one viewing angle over the entire surface of the display, while displaying the passenger information over the entire surface of the display in another in another viewing angle. These dual view display have to a great extent been achieved by using elongated vertical barriers or a lenticular array, much in the same way as in autostereoscopic (3D) displays.
In this embodiment of the invention however, the display device is divided into a first part 10a, intended for the display of driver information, and a second part 10b, intended for the display of passenger information. This arrangement provides advantages, particularly in relation to cost aspects, as will be further discussed below.
Briefly, the display device comprises a transmissive LCD panel 10 and a backlighting arrangement 12.
The LCD panel 10 comprises a number of sub-layers such as polarizers, etc., as is well known in the art. As mentioned above, first and second sections 10a, 10b are arranged to display driver and passenger information, respectively.
The backlighting arrangement 12 comprises a lightguide 11, which is capable of selectively emitting light with a first or a second angular distribution.
The backlighting arrangement 12 further comprises a first controllable shutter 14a, covering the first LCD panel sub-section 10a and a second controllable shutter 14b, covering the second LCD panel sub-section 10b. The shutters 14a, 14b may be devised as liquid crystal shutters, which are per se well known. In Mode A the first shutter 14a is made transmissive while the second shutter 14b is blocking. Thus the first LCD panel sub-section 10a is illuminated with light having the first angular distribution 16a, which may be suitable for viewing the image from a first angular position in relation to the display device, e.g. at the position of the driver.
At the same time, the first shutter 14a is made blocking and the second shutter 14b is made transmissive. Therefore, the second image sub-section is illuminated with light having the second angular distribution 16b, which may be suitable for viewing the image from a second angular position in relation to the display device, e.g. at the position of a passenger.
The display device may rapidly alternate between Mode A and Mode B, thus displaying the content of sub-section 10a in one direction and the content of sub-section 10b in another. This can be done without quickly changing the actual content displayed on the LCD panel sub-sections 10a, 10b, which means that the required LCD panel performance can be kept low, resulting in a comparatively inexpensive display device. The shutters must of course allow fast switching, but since these elements are only switched between blocking and fully transmitting, and since they may have quite coarse pixels, they are relatively inexpensive.
When the vehicle has stopped and the driver does not need to concentrate on the traffic environment, it may be suitable to drive the display panel in a third mode (Mode C), as illustrated in
Note in connection with the embodiment described above that the lightguide 11 and the light sources 18, 20 may be replaced with another arrangement, capable of selectively emitting light with a first or a second angular distribution. Note also that the first shutter 14a can in principle be omitted, thus allowing the passenger to see also the content of the first sub-section.
In the embodiment disclosed in connection with
As illustrated in
In summary, the invention relates to a dual view display device where a display surface is divided into a first and a second sub-section. A backlighting arrangement is used which provides light with different angular distributions to the different sub-sections. This allows at low cost e.g. in a vehicle the displaying of movies or computer game windows at a part of a display, which part is not visible for the driver of the vehicle.
The invention is not restricted to the described embodiments. It can be altered in different ways within the scope of the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
05108700 | Sep 2005 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/IB2006/053251 | 9/13/2006 | WO | 00 | 3/19/2008 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2007/034370 | 3/29/2007 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
5371510 | Miyauchi et al. | Dec 1994 | A |
5897184 | Eichenlaub et al. | Apr 1999 | A |
6231201 | Rupp | May 2001 | B1 |
6337721 | Hamagishi et al. | Jan 2002 | B1 |
6697201 | Watanabe | Feb 2004 | B2 |
6724450 | Knoll et al. | Apr 2004 | B1 |
7511683 | Sumiyoshi | Mar 2009 | B2 |
20030007227 | Ogino | Jan 2003 | A1 |
20040240777 | Woodgate et al. | Dec 2004 | A1 |
Number | Date | Country |
---|---|---|
0896897 | Feb 1999 | EP |
2404991 | Feb 2005 | GB |
2002099223 | Apr 2002 | JP |
2002228466 | Aug 2002 | JP |
2005024737 | Jan 2005 | JP |
2005257756 | Sep 2005 | JP |
2004088996 | Oct 2004 | WO |
Number | Date | Country | |
---|---|---|---|
20080258995 A1 | Oct 2008 | US |