The present invention relates to a backlight assembly, more particularly to a backlight assembly capable of enlarging color reproduction range and method of driving the same.
An interface, such as a display, plays a core role between a user and the environment in which enormous information are dealt with at high speed. Particularly, a flat panel display, which is slender, power saving, radiationless as well as compatible to manufacturing process of semiconductor, gradually occupies an important position in connecting a user and the above-mentioned environment. A flat panel display could be applied to diverse fields, such as consumer electronic products, personal mobile electronic products, medical instruments, and exploitation facilities, etc.
In the conventional liquid crystal display, color reproduction is achieved by the cooperation of the following components: cold cathode fluorescent lamp (CCFL), which provides white light as a backlight source, three-color color filter of the LCD and optical valve control of liquid crystal molecules. Color reproduction range depends on quality factors of backlight assembly, filters and display panel. Due to the limited properties of the material forming CCFL and color filter, the color gamut of most LCD TV on market is normally around 75% NTSC. In order to increase the chromaticity range of the reproduction of the display, a well-known design for manufacturers is a CCFL made of improved phosphors, such that the emission of the CCFL covers a larger color gamut. However, the cost of backlight assembly in the above design increases but lifetime and efficiency of the CCFL decrease; besides, the increase of color gamut is limitary which does not fulfill the requirement of the consumer. As compared to traditional backlight sources, backlight systems composed of Red, Green and Blue (RGB) light emitting diodes (LED) have high-saturated color that makes LCD generate 100% NTSC color gamut.
It is noteworthy that a great NTSC ratio is not equivalent to good color reproduction. Meanwhile, both yellow-orange and cyan cannot be well reproduced simultaneously since a trade-off exists in a triangular color gamut. A polygonal color gamut overcomes such defect. Take Pointer's gamut for example, which is one of the standards established for representing colors appeared in the real world, the range covered thereby is similar to a quadrilateral.
A popular design of changing the material of the color filters of one pixel on the display panel is utilized to create new color filters (sub-pixels) based on in the conventional RGB color filter array to obtain a polygonal color gamut, for example, yellow or cyan filters can be added thereto. Disadvantageously, the resolution of the above design decreases, moreover, the improved filter material, special sub-pixel structure and the consequent new driving/control system enormously increases expense on manufacturing flat panel displays, which are therefore uncompetitive.
Another design that provides two sets of RGB LED in the backlight assembly is also well-known in the market, by a sequential driving manner, the reproduction chromaticity range is enlarged. Nevertheless, the increased amount of driving circuits is consequent on two sets of LED. Moreover, the liquid crystal material must be chosen to respond quickly. Consequently, the cost of manufacturing such kind of backlight assembly grows significantly because the requirement of extra components and special liquid crystal material.
Given the above, flat panel displays in the marketplace have following disadvantages: insufficient color reproduction range, high power consumption as well as high manufacturing cost. Hence, a flat panel display having the advantages of broad color reproduction range, power saving as well as low manufacturing cost is desired on the market.
To overcome the above defects exist in the flat panel displays on the market, the present invention provides a backlight assembly, which makes a flat panel display achieve broad color reproduction range, and method of driving the same. A flat panel display that comprises the above backlight assembly advantageously covers broader color gamut, saves power consumption and reduces the unnecessary manufacturing cost.
An embodiment of the present invention provides a backlight assembly for a color image display panel, comprising: a plurality of light emission units, each unit having M kinds of emission components, each of the M kinds of emission components emitting light of a spectrum which is different from each other, wherein M is a positive integer equal to or greater than two; and a control unit receiving a first signal and determining a second signal according to the color information of the first signal, and individually controlling light emission of each emission component of the plurality of light emission units based on the second signal, wherein the light emissions from the plurality of light emission units generate a spatially-dependent spectrum distribution, and the light emission of each light emission unit forms a color gamut in a color space which is individually different from others.
In a preferable embodiment, color gamut of light emission of each light emission unit is formed dynamically according to frames of the first signal, so that light emission of the plurality of light emission units form globally a polygonal color gamut in a color space.
In a preferable embodiment, the emission component emits light of multiple colors, wherein light intensity of each color is individually controlled.
Another embodiment of the present invention provides a display system, comprising: a display panel; a backlight assembly comprising a plurality of light emission units, each light emission unit having M kinds of emission components, each of the M kinds of emission components emitting light of a spectrum which is different from each other, wherein M is a positive integer equal to or greater than two; and a control unit being operative to: receive a first signal; determine a second signal according to color information of the first signal; control individually light emission of the emission components of plurality of light emission units based on the second signal, wherein light emissions from the plurality of light emission units have a spatially-dependent spectrum distribution, and light emission of each light emission unit forms a color gamut in a color space which is individually different from others; determine an image signal applying to the display panel.
In a preferable embodiment, the image signal applied to the display panel is provided according to the first signal and a light emission result of the plurality of light emission units, wherein the light emission result of the plurality of light emission units is one of the spatially-dependent spectrum distributions generated by the plurality of light emission units.
In another embodiment, color gamut of light emission of each light emission unit is formed dynamically according to frames of the first signal, so that light emission of the plurality of light emission units form globally a polygonal color gamut in a color space.
In a preferable embodiment, the emission component emits light of multiple colors, wherein light intensity of each color is individually controlled.
Another embodiment of the present invention provides a method of displaying an colored image on a display system having a display panel and a backlight assembly, wherein the backlight assembly comprises a plurality of light emission units, each light emission unit having M kinds of emission components, each of the M kinds of emission components emitting light of a spectrum which is different from each other, wherein M is a positive integer equal to or greater than two, the method comprising: receiving a first signal; determining a second signal according to color information of the first signal; and controlling individually light emission of the emission components of the plurality of light emission units based on the second signal, wherein the light emissions from the plurality of light emission units have a spatially-dependent spectrum distribution, and the light emission of each light emission unit forms a color gamut in a color space which is individually different from others.
In a preferable embodiment, an image signal is provided to the display panel, wherein the image signal is provided according to the first signal and a light emission result of the plurality of light emission units, wherein the light emission result of the plurality of light emission units is one of the spatially-dependent spectrum distributions generated by the plurality of light emission units.
In another embodiment, the color gamut of light emission of each light emission unit is formed dynamically according to frames of the first signal, so that light emission of the plurality of light emission units form globally a polygonal color gamut in a color space.
The flat panel display according to the present invention has the following advantages: the backlight assembly needs neither extra driving circuits nor the special phosphor material; the display panel is commercial type and needs neither special filter material nor particular sub-pixel structure; the light emitted from the backlight assembly has a spatially-dependent spectrum distribution, such that the display of the flat panel covers a larger color gamut for increasing the range of color reproduction. Therefore, the cost of flat panel display of the present invention is not increased much comparing to traditional flat panel displays. Moreover, the backlight assembly of the present invention is not sequentially driven and therefore can save more power as compared to the display with sequential-driving backlight assembly.
Other objectives and achievements of the present invention could be realized with reference to the following description of the present invention and claims as well as the accompanied drawings.
The following embodiments of the present invention would be employed to illustrate the technical scheme of the present invention.
In one embodiment, the backlight assembly of the present invention comprises a plurality of light emission units, each of the plurality of light emission units corresponds to a display area of a display panel and has M kinds of emission components. Each of the M kinds of emission components emits light of a spectrum which is different from each other, wherein M is a positive integer equal to or greater than two.
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In addition to light emission units 102-402, the backlight assembly 100-400 shown in
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In another embodiment of the present invention, the display panel 530 comprises N color filter elements (not shown in the drawings) having bands different from each other for passing through light of different wavelengths, wherein N is a positive integer equal to or greater than three. The spectrums of light emitted from the plurality of light emission units are independent of each other, so light emission from the plurality of light emission units has a spatially-dependent spectrum distribution, and hence form globally a polygonal color gamut of the backlight assembly. In another embodiment, the light emission results of the M kinds of emission components are 1 or light emission distribution of the M kinds of emission components.
Take
Step 701: receiving a first signal;
Step 702: determining a second signal according to color information of the first signal; and
Step 703: driving light emission of M kinds of the emission components of the plurality of light emission units based on the second signal.
In this manner, spectrums of light emitted from the plurality of light emission units are independent of each other, so light emission from the plurality of light emission units has a spatially-dependent spectrum distribution, and hence form globally a polygonal color gamut of the backlight assembly.
In another embodiment of the present invention, the driving method 700 further comprises step 702′ (not shown in the drawings): the second signal determining each light emission unit by individually controlling light intensity of the M kinds of emission components so as to form a spatially-dependent spectral distribution.
In light of the above, the backlight assembly or flat panel display provided by the present invention has at least the following advantages: The light emitted from the backlight assembly of the present invention covers a larger polygon color gamut for increasing the range of color reproduction in flat panel display. Therefore, the cost of flat panel display with the backlight assembly is not increased much comparing to traditional flat panel display.
The technical content and features of the present invention are described above, however, those skilled in the art can make various modifications and variations without departing from the teaching and disclosure of the present invention. In view of the foregoing, the scope of the present invention is not limited to the disclosed embodiments, but covers other modifications and variations of the present invention that fall within the scope of the following claims.