Earlier this quarter the US Patent & Trademark Office published a patent application from Samsung that supports their concept curved TV that they demonstrated a year ago at CES 2013 along with a smartphone that provides for a much curvier display than their original Galaxy Round design.
Samsung's Patent Background
Liquid crystal displays have been adopted as displays for use in television receivers and are continuously being developed to have wider sizes to meet viewer's demands. The increasing size of the screen, however, is accompanied with a drawback of increased difference of viewpoints between when the viewer watches the center and when he or she watches left and right ends of the screen. Throughout the description, the term "viewpoint" as used herein may be defined as an angle between an eyeline of the observer who watches the screen and a tangent of the observed screen and the expression "difference of viewpoint" as used herein is defined as a difference of such angle.
Another shortcoming of a wide-screen television liquid crystal display is increasing glare-off. The problems associated with the difference of viewpoints can be dealt with by curving in the screen. However, when curved in, the display panel is subject to stress (`curvature stress`), which then leads to defective display performance as a result of problems such as a black mura defect or yellowish defect.
The mura defect is a contrast type defect in the region base, which is a phenomenon of pixel groups at a specific area being displayed brighter or darker than the rest of peripheral pixels, instead of being displayed with the same uniform brightness as the other pixels. The `black mura` is the specific display defect in which a specific pixel group is displayed darker than the peripheral pixels. The mural defect can be defined as a different or abnormal light emitting area (of pixels on the substrate) in comparison to a peripheral area, or as patternized brightness non-uniformity (BMU).
Meanwhile, the `yellowish defect` refers to a display defect according to which a displayed image contains yellowish color components. The yellowish defect can occur due to smaller transmissivity of B color pixels corresponding to blue color when the image is displayed in a combination of three colors, i.e., red (R), green (G) and blue (B) colors.
Samsung's Curved Display Invention
According to Samsung's patent filing, exemplary embodiments found in their invention may overcome the disadvantages noted in their patent background along with other disadvantages not covered earlier. Samsung cautions that not every aspect of the drawbacks noted above could be addressed by their invention.
In general, Samsung's invention is about a curved display apparatus which may include a display panel and a fixation member which fixes the display panel so that the display panel is curved with multiple curvatures.
Another technical aspect of the exemplary embodiments is to provide a display apparatus which may include a display panel which displays an image, first and second members which respectively support the display panel at front and rear locations of the display panel so that the display panel is curved with multiple curvatures.
The first and second members each provide support so that a first region of the display panel maintains a first curvature, a second region on a left side of the first region maintains a second curvature which is smaller than the first curvature, and a third region on a right side of the first region maintains a third curvature which is smaller than the first curvature.
Another technical aspect of the exemplary embodiments is to provide a curved display apparatus which may include a display panel which displays an image, a backlight unit which is arranged in back of the display panel, and a top chassis and a bottom chassis which package the display panel and the backlight unit into a single module, and support the display panel so that the display panel is curved with multiple curvatures.
A rear surface of the top chassis and a front surface of the bottom chassis each contact the display panel, and the rear surface of the top chassis and the front surface of the bottom chassis may each include a first supporting region which provides support so that a center of a curved region of the display panel with multiple curvatures maintains a first curvature, and second and third supporting regions which provide support so that sides of the display panel respectively maintain second and third curvatures which are smaller than the first curvature.
Curved Displays for Smartphones
Leaping to Samsung's patent FIG. 19 we see a possible future Samsung smartphone with a more dramatic curved display. The display member DP4 is arranged in a portrait fashion to display images, and a fixation member FM4 to fix the display member DP4 so that the display member DP4 is convexly curved with multiple curvatures.
Samsung confirms that the curved display apparatus 400 as illustrated in FIG. 19 may be implemented for use in a middle or small-sized display apparatus such as a mobile phone or smartphone which is used in contact with a user's face.
In patent FIG. 19 the fixation member FM4 is curved with three vertical radii of curvature, fixes the display member DP4, the display member DP4 is curved to have three vertical radii of curvature. For example, the first vertical radius of curvature VR1 corresponding to the edge portion of the display member DP4 is larger than the second vertical radius of curvature VR2 corresponding to the center, and the third vertical radius of curvature VR3 corresponding to the intermediate area between the edge portion and the center is smaller than the first vertical radius of curvature VR1 and is larger than the second vertical radius of curvature (VR2).
Portrait-Type Convex-Curved Smartphone Display
Samsung's patent FIG. 20 noted below is a schematic, exploded perspective view provided to explain the curved display apparatus 400 of FIG. 19. FIG. 20 particularly illustrates a portrait-type, convex-curved display apparatus #400 having an edge-type backlight assembly. In patent FIG. 20 we're able to see the smartphone's curved display include a display panel (#410), a backlight assembly and a top chassis (#470).
Other technical aspects include an array substrate #412, a color filter substrate #414 facing the array substrate and a liquid crystal layer (not illustrated) interposed between the array and color filter substrates.
It should also be noted that Samsung did provide alternative designs for their smartphones with one, for example, providing a different backlighting system similar to the one that is used in patent FIG. 6 noted below.
Curved Displays for Televisions
Samsung's patent FIG. 1 is a perspective view provided to explain a curved television which includes a display member DP1 arranged in a landscape relationship to display an image, and a fixation member FM1 which fixes the display member DP1 at multiple curvatures and in a concave-curved manner.
The patent filing supports Samsung's concept curved TV that they first presented at CES 2013 (see CNET video below). A photo of that TV is presented below – even though Samsung's curvaceous model outshined their television. Yet we get the marketing point that they were trying to convey (that it's a curvy TV).
Samsung's patent FIG. 6 noted below represents a curved display Television which includes a display panel 110, a backlight assembly and a fixation member. The display panel and the backlight assembly are defined in the patent as a display member. The curved display apparatus illustrated in FIG. 1 may be implemented as a middle-sized display apparatus such as computer monitor, or a large-sized display apparatus having a wide screen such as a wide-screen television.
The Display Panel
The display panel (#110) may additionally include a first polarization film (not illustrated) arranged on a lower side of the array substrate (#112), and a second polarization film (not illustrated) arranged on an upper side of the color filter substrate (#114). The first polarization film includes a transmittance axis of first direction to thus polarize the light to the first direction. The second polarization film includes a transmittance axis of a second direction, to thus polarize the light to the second direction. For example, the transmittance axes of the first and second polarization films may be arranged perpendicularly to each other.
The Backlight Assembly
The backlight assembly is arranged on the lower portion of the display panel to provide the display panel with the light. Generally, the backlight assembly is classified as either a direct type or an edge type. A direct type backlight assembly has a plurality of light sources arranged on the lower surface of a diffusion plate (#124) to advance the light to the back side of the display panel.
In contrast, an edge type backlight assembly includes a plurality of light sources arranged to face the side of a light guide panel, and a plurality of optical sheets (#122) arranged between the display panel and the light guide panel. The edge type backlight assembly changes a line or point of light fed from the light sources into planar light transmitted through the light guide panel, and advances the converted planar light to the back side of the display panel through the optical sheets.
In one exemplary embodiment, the backlight assembly is a direct type backlight assembly. The backlight assembly may include a light source module (#130), optical sheets, a diffusion plate, a reflection plate (#140), a bottom chassis 150 and a molding member #160.
The Light Source Module
The light source module includes a plurality of light emitting diode (LED) packages (#132) with a plurality of LEDs mounted thereon, and a printed circuit board (PCB) 134 on which the ED packages 132 are mounted. On the PCD 134 is formed a plurality of signal lines (not illustrated) to feed driving voltage to the LED packages 132. The light source module 130 may be arranged in accordance with a direction which is parallel to a shorter side of the display panel 110. Alternatively, the light source module 130 may be arranged in accordance with a direction which is parallel to a larger side of the display panel 110.
The optical sheets (#122) are arranged on the upper portion of the diffusion plate to increase the efficiency of the incoming light fed from the diffusion plate. The optical sheets may include a diffusion sheet to re-diffuse the light which is diffused at the diffusion plate and a prism sheet to converge the light diffused at the diffusion sheet to a front surface. For example, the prism sheet may include a vertical prism sheet to focus the light in the vertical direction, and a horizontal prism sheet to focus the light in the horizontal direction.
The reflection plate is arranged on a lower portion of the light source module to reflect the incoming light fed from the light source module.
The patent which was published by the US Patent Office earlier this quarter was originally filed for in the US back in May 2013 and one year earlier in Korea. Considering that this is a patent application, the timing of such products to market is unknown at this time.
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