Patent Publication Number: US-2016246111-A1

Title: Display panel and method of fabricating the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display panel and method of fabricating the same, and more particularly, to a display panel with high aperture ratio and low color deviation and method of fabricating the same. 
     2. Description of the Prior Art 
     Display panel e.g. liquid crystal display (LCD) panel is normally assembled by an array substrate and a color filter substrate (CF substrate). The array substrate includes thin film transistor (TFT) devices and peripheral circuit disposed thereon, and the CF substrate includes color filters e.g. red color filters, green color filters and blue color filters formed thereon. Considering the orientation shift between the array substrate and the CF substrate in assembly process, the width of black matrix must be enlarged to shield light leakage. The width incremental of the black matrix, however, reduces the area of light transmission region of the display panel, and thus adversely affects the aperture ratio of the display panel. 
     SUMMARY OF THE INVENTION 
     It is therefore one of the objectives of the present disclosure to provide a display panel and a fabrication method thereof to increase aperture ratio and to diminish color deviation. 
     According to an embodiment of the present disclosure, a display panel is provided. The display panel includes a first substrate, a plurality of thin film transistor (TFT) devices, a first color filter, a second color filter and a plurality of auxiliary color filter patterns. The first substrate has a first sub-pixel region and a second sub-pixel region. The thin film transistor (TFT) devices are disposed on a surface of the first substrate and located respectively in the first sub-pixel region and the second sub-pixel region. The first color filter is disposed on the surface of the first substrate of the first sub-pixel region, wherein the first color filter has a first opening at least partially corresponding to the thin film transistor device in the first sub-pixel region. The second color filter is disposed on the surface of the first substrate of the second sub-pixel region, wherein the second color filter has a second opening at least partially corresponding to the thin film transistor device in the second sub-pixel region, and the first color filter and the second color filter have different light transmission spectra. The auxiliary color filter patterns are respectively disposed in the first openings and the second openings, wherein the auxiliary color filter patterns disposed in the first openings and the second openings have the same light transmission spectrum. 
     According to another embodiment of the present disclosure, a method of fabricating a display panel is provided. The fabrication method includes the following steps. A first substrate is provided. A plurality of thin film transistor (TFT) devices are formed on the first substrate, wherein the thin film transistor devices are respectively disposed in a first sub-pixel region and a second sub-pixel region of the first substrate. A first color filter is formed in the first sub-pixel region of the first substrate, wherein the first color filter has a first opening at least partially corresponding to the thin film transistor device in the first sub-pixel region. A second color filter is formed in the second sub-pixel region of the first substrate, wherein the second color filter has a second opening at least partially corresponding to the thin film transistor device in the second sub-pixel region, and the first color filter and the second color filter have different light transmission spectra. A plurality of auxiliary color filter patterns are formed in the first openings and the second openings, wherein the auxiliary color filter patterns disposed in the first openings and the second openings have the same light transmission spectrum. 
     The color filters of the display panel of the present disclosure are disposed on the array substrate, and thus the aperture ratio of the display panel is improved. In addition, the TFT devices of the sub-pixel regions configured to display images of different colors are covered with the auxiliary color filter patterns of the same color, and thus all the TFT devices have identical leakage currents and identical device characteristic. Accordingly, color deviation is avoided. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a display panel according to a comparative embodiment of the present disclosure. 
         FIG. 2  is a diagram illustrating the relation between light absorption coefficient of the semiconductor channel layer and wavelength and the spectrum of back light. 
         FIG. 3  is a schematic diagram illustrating a display panel according to a first embodiment of the present disclosure. 
         FIG. 4  is a schematic diagram illustrating a display panel according to an alternative embodiment of the first embodiment of the present disclosure. 
         FIG. 5  is a schematic diagram illustrating a display panel according to a second embodiment of the present disclosure. 
         FIG. 6  is a schematic diagram illustrating a display panel according to an alternative embodiment of the second embodiment of the present disclosure. 
         FIG. 7  is a schematic diagram illustrating a display panel according to a third embodiment of the present disclosure. 
         FIG. 8  is a flow chart illustrating a method of fabricating a display panel according an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     To provide a better understanding of the present invention to the skilled persons in the technology of the present invention, preferred embodiments will be detailed as follows. The preferred embodiments of the present invention are illustrated in the accompanying drawings with numbered elements to elaborate the contents and effects to be achieved. 
     Refer to  FIG. 1 .  FIG. 1  is a schematic diagram illustrating a display panel according to a comparative embodiment of the present disclosure. As shown in  FIG. 1 , the display panel  1  of the comparative embodiment includes a first substrate  10 , a plurality of thin film transistor (TFT) devices T, a first color filter  21 , a second color filter  22 , a third color filter  23 , a plurality of pixel electrodes PE, a second substrate  30 , an opto-electric medium layer  32 , a black matrix BM and a common electrode CE. The first substrate  10  is an array substrate, which may be a transparent substrate e.g. a glass substrate, a plastic substrate or other suitable rigid or flexible substrates. The first substrate  10  has a first sub-pixel region  101 , a second sub-pixel region  102  and a third sub-pixel region  103  for displaying images of three different colors. The TFT devices T are disposed on a surface  10 A of the first substrate  10  and respectively located in the first sub-pixel region  101 , the second sub-pixel region  102  and the third sub-pixel region  103 . The TFT device T includes a gate electrode G, a gate insulating layer GI, a semiconductor channel layer SE, a source electrode S and a drain electrode D. The first color filter  21 , the second color filter  22  and the third color filter  23  are disposed on the surface  10 A of the first substrate  10  and respectively located in the first sub-pixel region  101 , the second sub-pixel region  102  and the third sub-pixel region  103 , and the first color filter  21 , the second color filter  22  and the third color filter  23  respectively cover the corresponding TFT devices T. In addition, each of the first color filter  21 , the second color filter  22  and the third color filter  23  has a first contact hole TH 1 , and the first contact holes TH 1  respectively expose or uncover the drain electrodes D of the TFT devices T. In the comparative embodiment, the first color filter  21 , the second color filter  22  and the third color filter  23  are a red color filter, a green color filter and a blue color filter respectively, i.e. the first sub-pixel region  101 , the second sub-pixel region  102  and the third sub-pixel region  103  are respectively a red sub-pixel region, a green sub-pixel region and a blue sub-pixel region, which together form a pixel region able to provide full-color images. Also, an overcoat layer  24  may selectively covers the first color filter  21 , the second color filter  22  and the third color filter  23 , and the overcoat layer  24  includes a plurality of second contact holes TH 2  connecting the first contact holes TH 1  respectively. The pixel electrodes PE are disposed on the surface  10 A of the first substrate  10  and respectively located in the first sub-pixel region  101 , the second sub-pixel region  102  and the third sub-pixel region  103 , and the pixel electrodes PE are electrically connected to the drain electrodes D of the TFT devices T respectively through the first contact holes TH 1  and the second contact holes TH 2 . The second substrate  30  is a counter substrate, which is disposed opposite to the first substrate  10 , and the second substrate  30  may be a transparent substrate e.g. a glass substrate, a plastic substrate or other suitable rigid or flexible substrates. The black matrix BM (also referred to as a light-shielding pattern) is disposed on a surface  30 A of the second substrate  30 . The common electrode CE is disposed on the surface  30 A of the second substrate  30  and the black matrix BM. In the comparative embodiment, the opto-electrical medium layer  32  may include, for instance, a liquid crystal layer interposed between the surface  10 A of the first substrate  10  and the surface  30 A of the second substrate  30 . 
     As shown in  FIG. 1 , the display panel  1  of the comparative embodiment is a COA (color filter on array) display panel, in which the first color filter  21 , the second color filter  22  and the third color filter  23  are disposed on the first substrate (array substrate)  10 , instead of on the second substrate (counter substrate)  30 , therefore, light leakage due to the alignment shift between the first substrate  10  and the second substrate  30  is avoided. Consequently, the width of the black matrix BM can be reduced to increase the aperture ratio. 
     The black matrix BM is able to shield most part of environmental light, but some environmental light may still enter the display panel  1 , penetrates through the first color filter  21 , the second color filter  22  and the third color filter  23 , and reaches the semiconductor channel layers SE of the TFT devices T. Furthermore, the semiconductor channel layers SE of the TFT devices T may also be irradiated by back light provided by backlight module (not shown) due to reflection or refraction effect. When the semiconductor channel layer SE is irradiated by environmental light and/or back light, current leakage will occur to the TFT device T. As a result, the device characteristic will be affected, for example, threshold voltage will be shifted and lifetime will be reduced. Refer to  FIG. 2 , as well as  FIG. 1 .  FIG. 2  is a diagram illustrating the relation between light absorption coefficient of the semiconductor channel layer and wavelength and the spectrum of back light, wherein amorphous silicon is exemplarily selected as the material of the semiconductor channel layer SE, and white light provided by white light LED device is exemplarily selected as the back light. As shown in  FIG. 2 , the light absorption coefficient of amorphous silicon is significantly inversely proportional to wavelength, that is, amorphous silicon has higher light absorption coefficient with respect to light beam with short wavelength e.g. blue light, and amorphous silicon has lower light absorption coefficient with respect to light beam with long wavelength e.g. red light, wherein the red light wavelength (λ R ) is longer than the blue light wavelength (λ B ). In addition, within the spectrum of the back light emitted by white light LED device, the intensity of light within blue light wavelength range is usually higher than the intensity of light within green light and red light wavelength ranges. In other words, the environmental light (white light) or the back light (white light) will be filtered and become red light within red light wavelength (λ R ) after penetrating through the first color filter (red color filter)  21 , and the TFT device T of the first sub-pixel region  101  will have a first leakage current when the semiconductor channel layer SE thereof is irradiated by the red light. The environmental light (white light) or the back light (white light) will be filtered and become green light within green light wavelength ( 2  after penetrating through the second color filter (green color filter)  22 , and the TFT device T of the second sub-pixel region  102  will have a second leakage current when the semiconductor channel layer SE thereof is irradiated by the green light. The environmental light (white light) or the back light (white light) will be filtered and become blue light within blue light wavelength (λ B ) after penetrating through the third color filter (blue color filter)  23 , and the TFT device T of the third sub-pixel region  103  will have a third leakage current when the semiconductor channel layer SE thereof is irradiated by the blue light. Since the red light wavelength (λ R ) is longer than the green light wavelength (λ G ) and the green light wavelength (λ G ) is longer than blue light wavelength (λ B ), the first leakage current is smaller than the second leakage current, and the second leakage current is smaller than the third leakage current. In conclusion, the semiconductor channel layers SE of the TFT devices T of the sub-pixels of different colors are irradiated by light beams of different wavelengths, and thus the degrees of current leakage in the TFT devices T of the sub-pixels of different colors are diverse. This causes the TFT devices T of the sub-pixels of different colors to exhibit diverse device characteristics, deteriorating display effect. For example, cross-talk phenomenon will be observed when displaying an image having high greyscale difference due to light leakage of the TFT devices T or parasitic capacitance. Since the degrees of leakage current of the TFT devices T of the sub-pixels of different colors are diverse, that is, the leakage current in red sub-pixel is smaller than the leakage current in green sub-pixel and the leakage current in blue sub-pixel, a reddish image will be observed when observing the display panel  1 . Thus, there is a space for the display panel  1  of the comparative embodiment to be improved. 
     Refer to  FIG. 3 .  FIG. 3  is a schematic diagram illustrating a display panel according to a first embodiment of the present disclosure. As shown in  FIG. 3 , the display panel  2  of this embodiment is an LCD panel, in which a first substrate  10  may only include two types of sub-pixel regions configured to display images of two different colors. In this embodiment, the sub-pixel regions are first sub-pixel regions  101  and second sub-pixel regions  102 . The display panel  2  includes a plurality of TFT devices T, a first color filter  21 , a second color filter  22 , a plurality of auxiliary color filter patterns  25 , a plurality of pixel electrodes PE, a second substrate  30 , an opto-electric medium layer  32 , a black matrix BM and a common electrode CE. The TFT devices T are disposed on a surface  10 A of the first substrate  10  and respectively located in the first sub-pixel region  101  and the second sub-pixel region  102 . The TFT device T includes a gate electrode G, a gate insulating layer GI, a semiconductor channel layer SE, a source electrode S and a drain electrode D. The gate electrode G is electrically connected to a corresponding gate line (not shown), and the source electrode S is electrically connected to a corresponding data line (not shown). The material of the gate electrode G, the source electrode S and the drain electrode D may be e.g. metal or alloy, but not limited thereto. The material of the gate insulating layer GI may be inorganic insulating material and/or organic insulating material, but not limited thereto; the material of the semiconductor channel layer SE may be silicon e.g. amorphous silicon or polycrystalline silicon, or oxide semiconductor material e.g. indium gallium zinc oxide (IGZO), but not limited thereto. The TFT device T of this embodiment is a bottom gate type TFT device, but not limited thereto. For example, the TFT device T may be a top gate type TFT or other types of TFT devices. 
     The first color filter  21  is disposed on the surface  10 A of the first substrate  10  and located in the first sub-pixel region  101 , wherein the first color filter  21  has a first opening  21 A at least partially corresponding to the TFT device T of the first sub-pixel region  101 . The second color filter  22  is disposed on the surface  10 A of the first substrate  10  and located in the second sub-pixel region  102 , wherein the second color filter  22  has a second opening  22 A at least partially corresponding to the TFT device T of the second sub-pixel region  102 . In this embodiment, the first opening  21 A and the second opening  22 A may partially uncover the top surfaces Ta of the TFT devices T respectively. In an alternative embodiment, other layers e.g. a dielectric layer or a passivation layer may cover the TFT devices T, in such a case, the first opening  21 A and the second opening  22 A may partially uncover the top surface of the dielectric layer or the passivation layer over the top surfaces Ta of the TFT devices T. In addition, the first color filter  21  and the second color filter  22  have different light transmission spectra, i.e. when white light passes through the first color filter  21  and the second color filter  22 , the color and wavelength range of light coming out of the first color filter  21  are different from the color and wavelength range of light coming out of the second color filter  22 . For example, the first color filter  21  is a yellow color filter and the second color filter  22  is a blue color filter, but not limited thereto. By virtue of the aforementioned arrangement, the first sub-pixel region  101  is a yellow sub-pixel region and the second sub-pixel region  102  is a blue sub-pixel region, which together form a pixel region for providing full-color images. In an alternative embodiment, the first color filter  21  and the second color filter  22  are selected from the group consisting of a red color filter, a green color filter, a blue color filter, a yellow color filter, a cyan color filter, a magenta color filter and a color filter of another different color. The auxiliary color filter patterns  25  are disposed in the first openings  21 A and the second openings  22 A respectively, and the auxiliary color filter pattern  25  is a single-layered color filter pattern or a color filter layer of one single color, further the auxiliary color filter pattern  25  is not stacked by a plurality of color filter layers of different colors. The auxiliary color filter patterns  25  disposed in the first openings  21 A and the second openings  22 A have the same light transmission spectrum. In other words, after passing through the auxiliary color filter patterns  25  disposed in the first openings  21 A and the second openings  22 A, white light will become color light of the same color. For example, the auxiliary color filter pattern  25  is selected from the group consisting of a red color filter, a green color filter, a blue color filter, a yellow color filter, a cyan color filter a magenta color filter and a color filter of another different color. 
     In this embodiment, the first color filter  21  or the second color filter  22  has the same light transmission spectrum as the auxiliary color filter patterns  25 , and the light transmission spectrum of the auxiliary color filter pattern  25  is preferably equal to the first color filter  21  or the second color filter  22  which has the higher light transmission spectrum. Consequently, the leakage currents of all of the TFT devices T are weaker and consistent with each other, and the device characteristic of all the TFT devices T is uniform. In an embodiment, the light transmission spectrum of the first color filter  21  is higher than the light transmission spectrum of the second color filter  22 , e.g. the first color filter  21  is a yellow color filter, the second color filter  22  is a blue color filter, and the auxiliary color filter pattern  25  is either a yellow color filter or a blue color filter. The material of the first color filter  21 , the second color filter  22  and the auxiliary color filter pattern  25  may be photosensitive material such as color photoresist, which can be formed by exposure-and-development process. For example, the auxiliary color filter pattern  25  and either one of the first color filter  21  and the second color filter  22  (e.g. the first color filter  21 ) maybe formed by the same exposure-and-development process, while the other one of the first color filter  21  and the second color filter (e.g. the second color filter  22 ) may be formed by another exposure-and-development process, but not limited thereto. The material of the first color filter  21 , the second color filter  22  and the auxiliary color filter pattern  25  may include ink or other suitable material, and may be formed by inkjet printing, coating or other processes. 
     In addition, there are no other color filters disposed inside the first opening  21 A and the second opening  22 A, except for the auxiliary color filter pattern  25 . In other words, the auxiliary color filter pattern  25  may have single-layered structure, which has the advantages of simplified process, low cost, better yield and easy to control. The first opening  21 A and the second opening  22 A may be filled up with the auxiliary color filter patterns  25 , but not limited thereto. In this embodiment, the top surfaces  25 S of the auxiliary color filter patterns  25  disposed in the first openings  21 A and the second openings  22 A, the first top surface  21 S of the first color filter  21  and the second top surface  22 S of the second color filter  22  are substantially coplanar, but not limited thereto. Also, the auxiliary color filter pattern  25  may be in physical contact with the top surface Ta of the TFT device T, but not limited thereto. In an alternative embodiment, an insulating layer or other layers may be optionally disposed between the auxiliary color filter pattern  25  and the TFT device T. Furthermore, in this embodiment, the auxiliary color filter pattern  25  at least fully covers the semiconductor channel layer SE of the TFT device T, i.e. the area of the auxiliary color filter pattern  25  is larger than that of the semiconductor channel layer SE, and the auxiliary color filter pattern  25  and the semiconductor channel layer SE overlap in the vertical projection direction. 
     The first color filter  21  and the second color filter  22  each further has a first contact hole TH 1  at least partially uncovering the corresponding drain electrode D. The overcoat layer  24  is disposed on the surface  10 A of the first substrate  10  covering the first color filter  21 , the second color filter  22  and the auxiliary color filter patterns  25 , wherein the overcoat layer  24  has a plurality of second contact holes TH 2  connecting the first contact holes TH 1  respectively. The pixel electrodes PE are disposed on the overcoat layer  24  and disposed in the first sub-pixel region  101  and the second sub-pixel region  102  respectively, and each of the pixel electrodes PE is electrically connected to the corresponding drain electrode D through the corresponding first contact hole TH 1  and the corresponding second contact hole TH 2 . The opto-electric medium layer  32  may include, for example, a liquid crystal layer disposed between the surface  10 A of the first substrate  10  and the surface  30 A of the second substrate  30 . The pixel electrode PE and the common electrode CE are able to drive the opto-electric medium layer  32  so that back light is able to pass through the opto-electric medium layer  32  and move toward the second substrate  30  to display images. 
     Since the first color filter  21  and the second color filter  22  are disposed on the first substrate (array substrate)  10  instead of on the second substrate (counter substrate)  30 , the display panel  2  of this embodiment has the advantage of high aperture ratio. In addition, the TFT device T of each sub-pixel region is covered with the auxiliary color filter pattern  25  of the same color (the same light transmission spectrum), and thus the environmental light (white light) or the back light (white light) after passing through the auxiliary color filter patterns  25  will become light of the same wavelength. In such a case, when the TFT devices T of the first sub-pixel region  101  and the second sub-pixel region  102  are irradiated by the light of the same wavelength, the leakage currents are identical. Consequently, each of the TFT devices has identical device characteristic, and color deviation is avoided. 
     The display panel and method of fabricating the same are not limited by the aforementioned embodiment, and may have other different preferred embodiments. To simplify the description, the identical components in each of the following embodiments are marked with identical symbols. For making it easier to compare the difference between the embodiments, the following description will detail the dissimilarities among different embodiments and the identical features will not be redundantly described. 
     Refer to  FIG. 4 .  FIG. 4  is a schematic diagram illustrating a display panel according to an alternative embodiment of the first embodiment of the present disclosure. As shown in  FIG. 4 , in the display panel  2 ′ of the alternative embodiment, the light transmission spectrum of the auxiliary color filter patterns  25  is different from the light transmission spectrum of the first color filter  21  and the light transmission spectrum of the second color filter  22 . For example, the light transmission wavelength of the auxiliary color filter patterns  25  is longer than the light transmission wavelength of the first color filter  21  and the light transmission wavelength of the second color filter  22 . Accordingly, the leakage currents and device characteristics of the TFT devices T are identical, and color deviation is avoided. For example, the first color filter  21  is a yellow color filter, the second color filter  22  is a blue color filter, and the auxiliary color filter pattern  25  may be a red color filter, but not limited thereto. 
     Refer to  FIG. 5 .  FIG. 5  is a schematic diagram illustrating a display panel according to a second embodiment of the present disclosure. As shown in  FIG. 5 , different from the first embodiment, the display panel  3  of this embodiment includes three or more sub-pixel regions configured to display three or more images of different colors, e.g. a first sub-pixel region  101 , a second sub-pixel region  102  and a third sub-pixel region  103 . The display panel  3  further includes a first color filter  21 , a second color filter  22 , a third color filter  23  and a plurality of auxiliary color filter patterns  25 . The first color filter  21  is disposed on the surface  10 A of the first substrate  10  and located in the first sub-pixel region  101 , wherein the first color filter  21  has a first opening  21 A at least partially corresponding to the TFT device T of the first sub-pixel region  101 . The second color filter  22  is disposed on the surface  10 A of the first substrate  10  and located in the second sub-pixel region  102 , wherein the second color filter  22  has a second opening  22 A at least partially corresponding to the TFT device T of the second sub-pixel region  102 . The third color filter  23  is disposed on the surface  10 A of the first substrate  10  and located in the third sub-pixel region  103 , wherein the third color filter  23  has a third opening  23 A at least partially corresponding to the TFT device T of the third sub-pixel region  103 . In this embodiment, the first opening  21 A, the second opening  22 A and the third opening  23 A may partially uncover the top surfaces Ta of the TFT devices T respectively. In an alternative embodiment, other layers e.g. a dielectric layer or a passivation layer may cover the TFT devices T, in such a case, the first opening  21 A, the second opening  22 A and the third opening  23 A may partially uncover the top surface of the dielectric layer or the passivation layer over the top surfaces Ta of the TFT devices T. In addition, the first color filter  21 , the second color filter  22  and the third color filter  23  have different light transmission spectra, for example, the first color filter  21  is a red color filter, the second color filter  22  is a green color filter and the third color filter  23  is a blue color filter, but not limited thereto. By virtue of the aforementioned arrangement, the first sub-pixel region  101 , the second sub-pixel region  102  and the third sub-pixel region  103  are respectively a red sub-pixel region, a green sub-pixel region and a blue sub-pixel region, which together forma pixel region for providing full-color images. In an alternative embodiment, the first color filter  21 , the second color filter  22  and the third color filter  23  are selected from the group consisting of a red color filter, a green color filter, a blue color filter, a yellow color filter, a cyan color filter, a magenta color filter and a color filter of another different color. The auxiliary color filter patterns  25  are disposed in the first openings  21 A, the second openings  22 A and the third opening  23 A respectively. In this embodiment, the first opening  21 A, the second opening  22 A and the third opening  23 A may be filled up with the auxiliary color filter patterns  25 , and the top surfaces  25 S of the auxiliary color filter patterns  25  disposed in the first openings  21 A, the second openings  22 A and the third openings  23 A, the first top surface  21 S of the first color filter  21 , the second top surface  22 S of the second color filter  22  and the third top surface  23 S of the third color filter  23  are substantially coplanar, but not limited thereto. In addition, the auxiliary color filter patterns  25  disposed in the first openings  21 A, the second openings  22 A and the third openings  23 A have the same light transmission spectrum. For example, the auxiliary color filter pattern  25  is selected from the group consisting of a red color filter, a green color filter, a blue color filter, a yellow color filter, a cyan color filter a magenta color filter and a color filter of another different color. In this embodiment, one of the first color filter  21 , the second color filter  22  or the third color filter  23  has the same light transmission spectrum as the auxiliary color filter patterns  25 , and the light transmission spectrum of the auxiliary color filter pattern  25  is preferably equal to the first color filter  21 , the second color filter  22  or the third color filter  23  which has the higher light transmission spectrum. Consequently, the leakage currents of all of the TFT devices T are weaker and consistent, and the device characteristic of all the TFT devices T is uniform. For example, the first color filter  21  is a red color filter, the second color filter  22  is a green color filter, the third color filter  23  is a blue color filter, and the auxiliary color filter pattern  25  may be a red color filter, a green color filter or a blue color filter. Preferably, the auxiliary color filter pattern  25  is a red color filter, and may be formed by the same process as one of the first color filter  21 , the second color filter  22  or the third color filter  23 , but not limited thereto. Furthermore, in this embodiment, the auxiliary color filter pattern  25  at least fully covers the semiconductor channel layer SE of the TFT device T, i.e. the area of the auxiliary color filter pattern  25  is larger than that of the semiconductor channel layer SE, and the auxiliary color filter pattern  25  and the semiconductor channel layer SE overlap in the vertical projection direction. 
     Similar to the first embodiment, the first color filter  21 , the second color filter  22  and the third color filter  23  are disposed on the first substrate (array substrate)  10  instead of on the second substrate (counter substrate)  30 , and thus the display panel  3  of this embodiment has the advantage of high aperture ratio. In addition, the TFT device T of each sub-pixel region is covered with the auxiliary color filter pattern  25  of the same color (the same light transmission spectrum), and thus the environmental light (white light) or the back light (white light) after passing through the auxiliary color filter patterns  25  will become light of the same wavelength. In such a case, when the TFT devices T of the first sub-pixel region  101 , the second sub-pixel region  102  and the third sub-pixel region  103  are irradiated by the light of the same wavelength, the leakage currents are identical. Consequently, each of the TFT devices has identical device characteristic, and color deviation is avoided. 
     Refer to  FIG. 6 .  FIG. 6  is a schematic diagram illustrating a display panel according to an alternative embodiment of the second embodiment of the present disclosure. As shown in  FIG. 6 , in the display panel  3 ′ of the alternative embodiment, the light transmission spectrum of the auxiliary color filter patterns  25  is different from the light transmission spectrum of the first color filter  21 , the light transmission spectrum of the second color filter  22  and the light transmission spectrum of the third color filter  23 . For example, the light transmission wavelength of the auxiliary color filter patterns  25  is preferably longer than the light transmission wavelength of the first color filter  21 , the light transmission wavelength of the second color filter  22  and the light transmission spectrum of the third color filter  23 . Accordingly, the leakage currents and device characteristic of the TFT devices T are identical, and color deviation is avoided. 
     Refer to  FIG. 7 .  FIG. 7  is a schematic diagram illustrating a display panel according to a third embodiment of the present disclosure. As shown in  FIG. 7 , different from the first embodiment and the second embodiment, the display panel  4  of this embodiment is an electroluminescent display panel e.g. an OLED display panel, wherein the opto-electric medium layer  32  is an electroluminescent layer e.g. an organic light-emitting layer, and the electroluminescent layer may be capable of emitting a white light. In addition, a pixel defining layer (also referred to as a patterned back layer)  26  is disposed on the overcoat layer  24 , and the pixel defining layer  26  has a plurality of openings  26 A uncovering the pixel electrodes PE respectively. The opto-electric medium layer  32  is disposed in the openings  26 A and located on the pixel electrodes PE. In this embodiment, the pixel electrode PE may be a transparent electrode which serves as an anode, and the common electrode CE may be a reflective electrode which serves as a cathode. The pixel electrode PE and the common electrode CE are able to drive the opto-electric medium layer  32  to emit light, which will pass through the first color filter  21 , the second color filter  22  and the third color filter  23  and move toward the first substrate  10  to display images. Since the TFT device T of each sub-pixel region is covered with the auxiliary color filter pattern  25  of the same color (the same light transmission spectrum), and thus all the TFT devices T have identical leakage currents and identical device characteristic. Accordingly, color deviation is avoided. 
     Refer to  FIG. 8  as well as  FIGS. 3-7 .  FIG. 8  is a flow chart illustrating a method of fabricating a display panel according an embodiment of the present disclosure. As shown in  FIG. 8 , the method of fabricating a display panel includes the following steps. 
     Step  50 : As shown in  FIGS. 3-7 , a first substrate  10  is first provided. 
     Step  52 : As shown in  FIGS. 3-7 , a plurality of thin film transistor devices T are formed on the first substrate  10  and respectively disposed in a first sub-pixel region  101  and a second sub-pixel region  102  of the first substrate  10 . 
     Step  54 : As shown in  FIGS. 3-7 , a first color filter  21  having a first opening  21 A id formed in the first sub-pixel region  101  of the first substrate  10 . 
     Step  56 : As shown in  FIGS. 3-7 , a second color filter  22  having a second opening  22 A is formed in the second sub-pixel region  102  of the first substrate  10 , wherein the first color filter  21  and the second color filter  22  have different light transmission spectra. 
     Step  58 : As shown in  FIGS. 3-7 , a plurality of auxiliary color filter patterns  25  are formed in the first opening  21 A and the second opening  22 A, wherein the auxiliary color filter patterns  25  disposed in the first opening  21 A and the second opening  22 A have the same light transmission spectrum. 
     In conclusion, the color filters are disposed on the array substrate, not on the counter substrate, and thus the aperture ratio of the display panel is improved. In addition, the TFT devices of the sub-pixel regions configured to display images of different colors are covered with the auxiliary color filter patterns of the same color, and thus all the TFT devices have identical leakage currents and identical device characteristic. Accordingly, color deviation is avoided. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.