Patent Application
20090009443
The present invention relates to a display device having a primary function of displaying information, for example television (TV), computer data etc.
Examples of display devices may be a television or PC monitor, which often merely has a primary function of displaying TV, a picture, computer data or other information through a screen of the device. This kind of display device is used for many purposes and both continuously and discontinuously depending on the circumstance in which it is used. When the display device is not used, it is occasionally switched off especially in order to save energy.
When the display device is not used, it may also be used for another purpose. An example of such other purpose of using a television is known from JP-2002136650 A. The television of JP-2002136650 A discloses a liquid crystal television set having a fluorescent tube, which tube is provided in the television set for an additional use of the television in the form a table lamp. The lamp function of the television set is provided by adjusting the light from the fluorescent tube into white light by letting the light through the color filter of R/G/B (Red/Green/Blue). The fluorescent tube is in this way reused in order to bring about a second function of the television. By using the same kind of light source, in this case a fluorescent tube, for both the primary and secondary functions no power is saved when the primary function of the television set is switched off, since the light source is just used for the secondary function—in this case as a lamp.
Additionally, this kind of display device is usually switched off when it is not used for the primary function of displaying information or as the function of a lamp. In the switched off state the display device appears as a black box and does not fit into the environment in most surroundings, such as in a living room or in a conference room. Even though the appearance is dull, the display device is switched off in order to save energy.
As the display screens of the display device are becoming larger and larger, the black and dull mode of the display device when turned off appears consequently increasingly dull and fits less and less into the surroundings of the display device.
Hence, an improved display device, which does not appear black and dull when turned off, will be increasingly advantageous, and in particular while being more efficient and/or less energy consuming without deteriorating the display device itself would be advantageous.
Display devices, such as a television or a PC monitor, may also comprise a LCD, also called Liquid Crystal Display, or OLED, also called Organic Light Emitting Diode, display to present information in different colors by using a plurality of pixels. Normally each pixel has subpixels for emitting the colors such as the primary color, of R (Red), G (Green) and B (Blue).
Moreover, in case of an LCD each pixel is illuminated by a backlight of the display. The colors, which are emitted by each subpixel, are controlled by one or more transistors whereby one subpixel is controlled to emit a particular color as function of time for displaying the information, which color may be one of the primary colors or some of them combined. A pixel is for these reasons divided into an area for emitting the colors and a non-emitting area in which the one or more transistors for controlling are situated. The backlighting is operable to illuminate each pixel whereby part of that light which illuminates the non-emitting areas is blocked, and, as a result, wasted. The size of the non-emitting area is determined by the size of the controlling part.
The brightness of the display screen is at present influenced by how much backlight is wasted on illuminating the non-emitting areas of the pixels and thereby how large the black non-emitting area is. Furthermore the brightness of the screen is influenced by the picture resolution, which determines the size of each pixel, and by how much energy is put into the backlighting of the display.
In order to improve the brightness of the display screen and at the same time save energy the black non-emitting areas have over the years been decreased so that less light of the backlighting is wasted on illuminating the non-emitting areas of the pixel. Nevertheless the brightness of the display screen is still capable of being improved and hence an improved display device, in which information displayed appears even brighter, would additionally be advantageous, and in particular an improved efficiency and/or reduced energy consumption would be advantageous.
An objective of the present invention is to provide a display device, which appears more aesthetic when the device is not used for its primary purpose of displaying information or the like to the user, while reducing deterioration resulting from providing a more aesthetic appearance.
This objective and other advantages will be evident from below. The invention is defined by the independent claims. The dependent claims define advantageous embodiments.
By disposing a second illumination source substantially in the vicinity of the screen, a second illumination for displaying an image, a picture or information, for example a pattern, a photo, a logo or slogan or the like, to the user is obtained. Hereby a display device fitting more into its surroundings is obtained than for example a dull black box.
A display using a second illumination source for displaying one image, one picture or one view of information in stead of the first illumination source for displaying moving images, pictures or information consumes furthermore less energy since more units using energy is needed for displaying moving images, pictures or information than just for displaying one image, one picture or one view of information.
By turning on the second illumination source of the display for displaying an image, a picture or a photo when the first illumination source of the display device is turned off, the display device is transformed into an aesthetic creation and does no longer appears dull. The display device as an aesthetic creation may take the shape of a painting or a photo in a frame. The second illumination source of the display device may furthermore be used to provide a background illumination of the room in which the display device is present; the display may then provide a cozy and home-like atmosphere. The display device in the form of providing a cozy and home-like atmosphere may be used in the room instead of a dimmer or the like. By turning the display device into an aesthetic creation and/or a pleasant background lighting such a display device may then replace the aforementioned objects by just one device capable of providing the desired functions.
Furthermore, by turning on the second illumination source of the display device for displaying particular information, such as a logo or minor information in a static or in a dynamic fashion, when the first illumination source of the display device is turned off, the display device is then displaying only this particular information. The particular information may be from a user-defined source, for example PC, DVD or other medium. The second illumination source enables that the display device is used for a second purpose as mentioned above instead of having to use a separate second display device for showing this particular information. Additionally, the display device does no longer appear black and dull when the first illumination source is turned off in order to save energy.
Furthermore, the second illumination source of the display device may be turned on once the display device has registered that the display device has not been used for a short period of time in stead of the well known “screen saver”. The display device is thereby transformed into an aesthetic creation while not used, for example during a presentation, a lecture, or the display device might even display a joke or a comic strip to keep the receivers of the presentation or lecture awake.
Additionally, the second illumination source, with its associated units to enable its operation, may consume less energy than the first illumination source. It is hereby obtained that the display device is transformed into an aesthetic creation and simultaneously consuming less energy, when the first illumination source is turned off than when the first illumination source displays information. The aesthetic creation is hereby obtained with lower energy consumption compared to the normal display operation and without deterioration of the display itself.
The second illumination source may be disposed substantially peripherally to the display screen of the device. By disposing the second illumination source peripherally to the display screen, the screen is illuminated in a simple manner. Such a second illumination source can be easily incorporated into an existing display device without extensive construction changes.
The second illumination source may be situated behind or in front of the display screen. The second illumination source may for example be disposed directly on the front side of the screen or directly on the backside of the screen. The second illumination source may be incorporated by adding a layer onto the screen, which layer illuminates when exposed to electricity. A second illumination source is hereby obtained, which is easily incorporated in the existing design of a display device without making the display device larger or much more complicated in design, manufacture and construction. Additionally, the second illumination source may be disposed in the periphery behind or in front of the screen whereby an illumination of the screen in order to transform the display device into an aesthetic creation is obtained.
Additionally, the display device may comprise a source control unit for controlling which illumination source is operable to illuminate said screen. Furthermore, the second illumination source may be operable to be turned on in parts, which parts may be turned on one after the other, when the first illumination source is turned off. It is hereby obtained to transform a display device into lively aesthetic creation in that each part itself is an image displayed in turns. The display device is then for the same reason as above using less energy when the second illumination source is turned on and the first illumination source is turned off.
Another objective of the present invention is to provide an improved display device in which information displayed on the display screen of the device appears brighter without increasing the size of each pixel in the display device.
Another aspect of the present invention has for its object to provide an improved display device in which information displayed on the screen under high ambient light illumination light levels appears with higher contrast.
This objective and other advantages which will be evident from below are obtained by a display device comprising a display screen for displaying information to a user of the device, wherein the display screen may have at least one pixel with a blocking area, said device being operable in a first, second or third mode, wherein in said first or third mode a first illumination source of the device is operable to illuminate said screen for displaying said information, wherein in said second or third mode a second illumination source is disposed in the blocking area of the pixel to illuminate said screen.
By disposing a second illumination source in the blocking area of the pixel to illuminate said screen, the brightness of the displayed information in the display device is improved without increasing the size of each pixel in the display screen. The second illumination source enhances in the third mode the first illumination source in that both the first illumination source and the second illumination source in the third mode illuminates the screen, whereby the brightness of the displayed information is enhanced. Additionally, the blocking area of the pixel is used for another purpose besides making room for the pixel control unit, such as a transistor. Thereby, the picture resolution is not decreased in order to increase the brightness of the displayed information.
Furthermore, it is obtained that the second illumination source in the second mode may be used as an additional lightning when the first illumination source is turned off. The second illumination source may be used as additional lightning for many purposes, for example for illuminate a picture in order to present an off-state creation. When the television or PC monitor is turned off it appears dull and does not fit into the surroundings of the room in which the television or PC monitor is placed. By turning on the second illumination source in order to illuminate an image or the like, it is then possible to make the display screen into an aesthetic creation in stead of the dull black state appearance.
In yet another aspect of the present invention, the second illumination source in the third mode may emit substantially a comparable flux of light as the first illumination source or more in order to enhance the first illumination source. An enhanced brightness of the information or image displayed to the user is hereby obtained without increasing the size of each pixel in the display device.
Advantageously, the second illuminating source may according to another aspect of the present invention be arranged to be switched on simultaneously as the first illumination source.
In another aspect of the present invention, the display device may be operable in the third mode in which the second illumination source is operable to provide illumination in the same color or in a brighter color as the illuminated pixel from the first illumination source. A total brighter color and higher contrast is hereby obtained.
The second illumination source is turned to the same color as the pixel that is illuminated by the first illumination source, to largely enhance the color brightness and contract—improve image quality. The color of the second illumination source may thus be individually selected/generated for every pixel according to the image information (color) to be displayed on the pixel.
Advantageously, the second illumination source in the third mode may emit substantially a flux of light in ratio of 5:1 to the first illumination source, preferably in the ratio of 3:1, according to another aspect of the present invention.
Furthermore, the display device may have a pixel control unit for controlling which color the pixel is emitting, and that the second illumination source may be situated between the pixel control unit and the pixel. The second illumination source may then act as a blocking area when the first illumination source is turned on and a second process of providing a blocking area may be omitted.
Additionally, the display device may have a pixel control unit for controlling which color the pixel is emitting, and that the pixel control unit may be situated at a back side of the pixel closest to the first illumination source and that second illumination source is situated in front of the pixel. It is likewise obtained that the second illumination source then may act as a blocking area when the first illumination source is turned on and a second process of providing a blocking area may be omitted. Furthermore, the light emitted from the second illumination source is not interrupted by being directed through the pixel whereby some of the light may be diverted and wasted.
In another aspect of the present invention, the second illumination source may be an organic or inorganic light emitting area. By being an organic light emitting area the second illumination source may comprise an OLED (organic light emitting diode) or a PLED polymer based light diode), which takes up a very small space compared to other types of lightning. The same advantage is obtained if the second illumination source comprises an inorganic light-emitting source. Furthermore, when the second illumination source comprises an inorganic film EL structure, high production temperature will not cause a problem as for the organic light emitting area.
In yet another aspect of the present invention, the organic or inorganic light emitting area may be applied to the pixel to form the blocking area by a deposition process, a printing process, a filtering process or a spraying process in the form of a film. By applying the organic or inorganic light emitting area by one of these processes, it is possible to provide the blocking area in an easy and precise manner.
Additionally, the light emitting area according to an aspect of the present invention may comprise a injection layer, a transport layer, a light emitting layer, a blocking layer, an electron transport layer or a second electrode layer or a combination thereof.
Furthermore, the light emitting area may according to the present invention comprise a inorganic layer, such as ZnS, Mn, Th or a combination thereof. The inorganic layer when comprising one of ZnS, Mn, Th may when subjected to a certain voltage emit light of substantially one color and when the layer comprises a combination thereof different colors in the same pixel may be obtained. It is also possible to provide one pixel with one of ZnS, Mn, Th and another pixel with another of ZnS, Mn, Th. It is hereby possible to provide an image of different colors and thereby make the display device into a decoration, which may fit, into the surroundings of the device.
Additionally, the light emitting area may according to the present invention comprise a polymer based organic light emitting diode (PLED), which is easy to adhere to the pixel and thereby very production friendly.
Another aspect of the present invention relates to a method of displaying information to a user of the aforementioned display device, comprising the step of switching on the first illumination source, wherein the method further comprises the step of switching on a second illumination source disposed in the blocking area of a pixel in the display screen to illuminate said screen.
Yet another aspect of the invention relates to a method comprising the steps of switching off the first illumination source when switching on the second illumination source.
The present invention will in the following be described by way of example only with reference to the accompanying drawings, in which:
The same reference numerals in different Figs. represent the same or similar items.
An embodiment of a display device 5 according to the invention for displaying information by means of a first illumination source to a user of the display device is shown in
In
The second illumination sources are in
The second illumination source 7 may be disposed directly on the backside of the screen, as shown in
The second illumination source 7 may be incorporated at the front of internal components 1 as shown in
The display device 5 has a display panel comprising pixels 19 each controlled by at least one pixel control unit comprising one or more transistors.
The pixel 19 in
The pixel 19 shown in
Additionally or alternatively, in a third mode both the first illumination source 6 and the second illumination source 7 may be turned on simultaneously. When both illumination sources are turned on, the second illumination source 7 generates a bright color in order to enhance the image or information displayed using the first illumination source 6. By the wording bright color is meant substantially a flux of light in the order of 20% of the level of the first illumination source or more in order to enhance the first illumination source. Furthermore, the second illumination source 7 may illuminate one or more window areas for emitting the primary colors R, G, B, which are also receiving light from the first illumination source 6. This enhances the image or information displayed using the first illumination source 6.
The component 1 as shown in
The second illumination source 7 may be provided directly on such pixel 1 of the display device 5. The second illumination source 7 may be placed on the backside of the pixel in relation to the display screen 8, as shown in
In both aspects shown in
In an embodiment, the second illumination source 7 serves as the blocking layer thereby covering an area which is about the size of the pixel control unit 4 or a little larger than this size. The second illumination source 7 may be applied onto the back side or the front side of the pixel 19 similar as shown in
Such OLEDs comprises as a minimum a substrate, a bottom electrode, commonly configured to be an anode, a top electrode, commonly configured as a cathode, spaced from bottom electrode, and a light emitting layer. At least one electrode is (semi-) transparent for light generated in the light emitting layer of the OLED. In one embodiment the cathode comprises a semi-transparant layer, for example 35 nm of BA, and a hightly refective layer, for example 100 nm Aluminum. The anode comprises a transparent conductive layer for example ITO, also called indium-tin oxide. This construction of an OLED is known as the so-called “Black Cathode” technology of the company Luxell (SID 94 Digest page 140) and is also called an OLED “Black Matrix”. The Oled can also comprise a hole-injecting layer, a hole-transporting layer, an electron-transporting layer, and an electron-injecting layer.
The substrate can be an organic solid, an inorganic solid, or a combination of organic and inorganic solids. Typical substrate materials include glass, plastic, metal, ceramic, semiconductor, metal oxide, semiconductor oxide, semiconductor nitride, or combinations thereof. The substrate can be a homogeneous mixture of materials, a composite of materials, or multiple layers of materials. The substrate can be an OLED substrate, namely a substrate commonly used for preparing OLED devices, for example active-matrix low-temperature polysilicon or amorphous-silicon TFT substrate. The substrate can either be light transmissive or opaque, depending on the intended direction of light emission. Suitable materials for use in a hole-injecting layer are, but are not limited to, porphyrinic compounds, plasma-deposited fluorocarbon polymers, and inorganic oxides including vanadium oxide, also called VOx, molybdenum oxide, also called MoOx, nickel oxide, also called NiOx, and so forth.
The hole transporting layer may comprise naphthalene-diphenyl-benzidine, also called NPB. Examples of electron injecting materials may comprise alkaline or alkaline earth metals, alkali halide salts, such as LiF or alkaline or alkaline earth metal doped organic layers.
The OLED “Black Matrix” works as a perfect Black Matrix when turned off. When this second illumination source is turned on, for example when a voltage of 3-8 V is applied to the electrodes, the OLED “Black Matrix” emits light.
Any emission color of the OLED “Black Matrix” can be realized either monochrome over the whole display screen 8 or segmented between different areas. The aforementioned cathodes and anodes may be addressed and interconnected in various ways to allow uniform illumination or selection of different areas or patterns in creating an image for a decoration purpose, as mentioned above.
In an embodiment, the second illumination source 7 in the form of the aforementioned OLED “Black Matrix” 7 is situated at the front side of the pixel 19 and the pixel control unit 4 is situated at the back side of the pixel 1, as shown in
In another embodiment, the OLED “Black Matrix” 7 may be provided on the backside of the display screen 8 as shown in
In a further embodiment, the second illumination source 7 may in stead of a so-called OLED “Black Matrix” comprise an inorganic film ElectroLuminescence (EL) structure, which structure can emit light when a voltage of 3-300 V, such as 100-250V is applied to the electrodes. The inorganic film EL structure can function as the OLED and can be realized either monochrome over the whole display screen 8 or segmented between different areas. The cathodes and anodes of the inorganic film EL structure may be addressed and interconnected in various ways to allow uniform illumination or selection of different areas or patterns in creating an image for a decoration purpose, as mentioned above.
In a further embodiment, the window areas for emitting the colors may be other colors than the primary colors as mentioned above.
Furthermore, these window areas for emitting the colors may of the present invention be OLEDs, PLEDs or made of an inorganic film EL structure, so that the first illumination source is situated in the pixel 19 and not behind in the form of backlighting. Both the first illumination source 6 and the second illumination source 7 may be selected from the same group comprising OLEDs, PLEDs or made of an inorganic film ElectroLuminescence (EL) structure.
The present invention can be applied on both LCD displays and on all kinds of OLED displays, such as small-molecule OLED, polymer based OLED, bottom emission OLED, top emission OLED, R/G/B primary OLED and white emitting OLED with color filters.
The second illumination source may in all embodiments be in the form of a point, a line or a plane light source. Furthermore, the display device 5 may be a direct view TV or a PC monitor regardless the exact display screen 8 used, comprising a CRT, also called cathode ray tube, a PDP, also called Plasma Display Panel, an LCD panel or an OLED panel or others.
For Plasma Display Panels the temperature during manufacturing is very high and in this case an inorganic Light Emitting Diode, also called LED dice, may advantageously be implemented to provide the second illumination source. This inorganic LED dice can easily be implemented within the barrier stripes of the PDP or even within its phosphor channels. LED dices can furthermore be selected to emit any color and depending on the number of dices and optical coupling to light guiding layers, the resulting illumination of the PDP can have any desired shape of an image.
In
The first illumination source is operable in a first mode in which the first illumination source is either turned on or turned off. Likewise is the second illumination source operable in a second mode in which the second illumination source is either turned on or turned off. The second illumination source may be operable to be turned on when the first illumination source is turned off and likewise may the first illumination source may be operable to be turned on when the second illumination source is turned off. The device may in the third mode be operable so that both the first and the second illumination source are turned either on or off. When both are turned on one of the sources is then executing the most illumination and will therefore determine for what may appear at the screen. The determining source may then be supported by the other source for displaying the image, picture, photo, information or data to the user.
The display device is operable in a first or third mode, when the first illumination source is turned on to display any kind of images, pictures, photos, information or data, which images, pictures, photos, information or data may displayed in a random order in order to create moving images, pictures, photos, information or data.
The wording blocking area is defined as being the area of a pixel where components for controlling the pixel are blocking the light illuminated from the first illumination source. This blocking area may also be called a non-emitting area of the pixel in the case where the second illumination source is not placed on the pixel.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
| Number | Date | Country | Kind |
|---|---|---|---|
| 05107110.8 | Aug 2005 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB06/52555 | 7/26/2006 | WO | 00 | 8/21/2008 |
