1. Field of the Invention
The present invention relates in general to a flat panel display (FPD). In particular, the present invention relates to a liquid crystal display (LCD) with a non-matrix light shielding structure.
2. Description of the Related Art
Liquid crystal displays (LCDs) are a well-known form of flat panel display with advantages of low power consumption, light weight, thin profile, and low driving voltage. Generally, in LCDs, a liquid crystal layer is disposed between two transparent substrates such as glass substrates, and one of the two transparent substrates is provided with switching devices, such as thin film transistors (TFTs). In the display area of the LCD, an array of pixel areas is defined by horizontally extended scan lines and vertically extended signal lines. Each pixel area has a thin film transistor and a pixel electrode.
In the upper substrate, a black matrix 12 is disposed on a portion of the upper glass substrate 11. The color filter layer 13 of red, green, and blue is disposed on another portion of the upper substrate corresponding to the pixel electrode. A common electrode 14 made of ITO is arranged on the black matrix 12 and the color filter 13.
U.S. Pat. Nos. 5,561,440 and 6,064,358 issued to Masaaki et al. on Oct. 1, 1996 and May 16, 2000 respectively, teaches that the light shielding structure disposed on the upper glass substrate has openings arranged in a matrix and is aligned with the TFT array on the lower glass substrate with each pixel electrode aligned with the opening in the light shielding structure and the edges of each pixel electrode are overlapped by the periphery of the light shielding structure. U.S. Pat. No. 6,424,394 issued to Morii on Jul. 23, 2002 teaches that the shape of the light shielding film is grid-shaped so as to transmit the light. As shown in
However, the black matrix 12 consisting of Cr on the upper substrate is subject to great stress due to the thermal expansion coefficient difference between the black matrix and the glass substrate and between the black matrix and the color filter when forming the upper substrate. The R, G, and B color filter may peel due to the stress induced by the thermal cycles required to manufacture the upper substrate and to be released from the black matrix.
To solve the above problems, it is an object of the present invention to provide a flat panel display to prevent the R, G and B color filter from peeling.
It is another object of the present invention to provide a flat panel display with reduced stress from the light shielding structure.
The present invention provides a flat panel display with a non-matrix light shielding structure. The non-matrix light shielding structure comprises a main shielding structure which has main spacings substantially corresponding to the pixel regions and gaps, and complementary shielding structures corresponding to the gaps. Each gap substantially corresponds to the scan line or signal line. Each main spacing is connected to at least one of the gaps, and each gap is connected to two adjacent main spacings.
The present invention provides a flat panel display, in which a liquid crystal layer is disposed between first and second substrates. The first substrate includes scan lines and signal lines intersecting to define pixel regions, pixel electrodes disposed in the pixel regions, stripe-shaped shielding layers disposed between the signal lines and the pixel electrodes and overlapping the pixel electrodes, and complementary shielding structures. The second substrate includes a main shielding structure having gaps and main spacings substantially corresponding to the pixel regions, and a color filter disposed on the main shielding structure. Each gap substantially corresponds to one of the scan lines or signal lines, each main spacing is connected to at least one of the gaps, and each gap is connected to two adjacent main spacings. The complementary shielding structures correspond to the gaps.
The present invention provides a flat panel display. Within a pixel unit, first and second scan lines are parallel to each other in a first direction; first and second signal lines are parallel to each other in a second direction, wherein the first and second scan lines and the first and second signal lines define a pixel region. A main shielding structure having a main spacing and a gap, in which the main spacing substantially corresponds to the pixel region and the gap is connected to the main spacing and an adjacent main spacing. A complementary shielding structure is disposed under the gap to partially overlap the main shielding structure.
The preferred embodiment of the invention is hereinafter described with reference to the accompanying drawings in which:
In order to reduce the stress from the light shielding structure while fabricating the upper substrate, the present invention provides a non-matrix light shielding structure. The liquid crystal display apparatus (liquid crystal panel) to which the present invention is applied are not particularly limited. The display can be of a reflective, transmissive, projective or transflective type, and the driving element formed on each pixel which is a minimum display unit can be a thin film transistor (TFT), a metal insulator metal (MIM), or similar, in order to provide improved image quality and superior resolution in the display.
Before explaining the light shielding structure of a liquid crystal display apparatus according to the present invention, an explanation will be made of the general structure of the liquid crystal display apparatus to which the present invention is applied referring to the drawings.
First Embodiment
In the first embodiment a specific example of a transmissive type liquid crystal display with TFTs as the driving element is given, and a detailed description is given hereinafter.
As shown in
As shown in FIGS. 1 and 2A-2C, for one pixel area the lower substrate 561 comprises a lower transparent substrate 556, a TFT 510, scan lines 501A and 501B extending in direction X, signal lines 500A and 500B extending in direction Y, a pixel electrode 554 as shown with dashed line, stripe-shaped shielding layers 551A and 551B and complementary shielding layers 509A, 509B, 519A and 519B. The scan lines 501A and 501B and the signal lines 500A and 500B define a pixel area, and a pixel electrode 554 shown in
As for the lower substrate 561, the left stripe shielding layer 551A is formed between the left signal line 500A and the pixel electrode 554 to partially overlap the periphery of the pixel electrode 554. Also, the right stripe shielding layer 551B is formed between the right signal line 500B and the pixel electrode 554 to partially overlap the periphery of the pixel electrode 554. As focused on the left side, a left complementary shielding structure, such as composed of complementary shielding layers 509A and 519A, is formed between the signal line 500A and the stripe shielding layer 551A to prevent light leakage therebetween. The left complementary shielding structure also can be an isolated shielding structure 529 overlapping the stripe shielding layer 551A and the signal line 500A (as shown in FIG. 8), a shielding structure 509′ overlapping the signal line 500A and contacting the stripe shielding layer 551A (as shown in FIG. 9), a shielding structure 519′ overlapping the stripe shielding layer 551A and contacting the signal line 500A (as shown in FIG. 10), or two sub-structures respectively contacting the stripe shielding layer 551A and the signal line 500A. The latter is described in this embodiment and figures.
As shown in
The complementary shielding layers 509A, 509B, 519A and 519B are complementary in the context that they are designed to overlap with certain fishbone-shaped spacings in a main shielding structure 559 formed in the upper substrate 562.
The upper substrate 562 comprises the transparent common electrode 563, the main shielding structure 559 and the color filter 560 of R (red), G (green) and B (blue), which are the three primary colors. In
The main shielding structure 559 disposed on the transparent substrate 558 is shown in
In order to provide a more detailed description,
The stripe shielding layers 551B and 551B and the complementary shielding layers 509A and 509B are disposed at a level lower than the signal lines 500A and 500B. For example, the stripe shielding layers 551A and 551B and the complementary shielding layers 509A and 509B are formed with the scan lines 501A and 501B and from a first metal layer (M1), and the signal lines 500A and 500B and the complementary shielding layers 519A and 519B are formed from a second metal layer (M2). After the stripe shielding layers 551A and 551B, the complementary shielding layers 509A and 509B and the scan lines 501A and 501B are formed in the first metal layer (M1), a gate insulating layer 555 is formed thereon, covering the first metal layer (M1). The signal lines 500A and 500B and the complementary shielding layers 519A and 519B are then formed in the second metal layer (M2) deposited on the gate insulating layer 555. A passivation layer 550 is then formed before forming the pixel electrode 554.
Now turning to several pixel areas as shown in
The main shielding structure 559 allows transmission of light passing through the pixel electrode 554 and operates in combination with the stripe shielding layers 551, the complementary shielding layers 509 and 519 to block light that does not pass through the corresponding pixel electrode 554.
Second Embodiment
In the second embodiment a specific example of a transmissive type liquid crystal display with TFT as the driving element is given in the following detailed description.
As shown in
As shown in FIGS. 11 and 12A-12C, for one pixel area the lower substrate 661 comprises a lower transparent substrate 656, a TFT 610, scan lines 601A and 601B extending in direction X, signal lines 600A and 600B extending in direction Y, a pixel electrode 654 as shown with dashed line, stripe-shaped shielding layers 651A and 651B and complementary shielding layers 639A and 639B. The scan lines 601A and 601B and the signal lines 600A and 600B define a pixel area, and a pixel electrode 654 shown in
As for the lower substrate 661, the left stripe shielding layer 651A is formed between the left signal line 600A and the pixel electrode 654 to partially overlap the periphery of the pixel electrode 654. Also, the right stripe shielding layer 651B is formed between the right signal line 600B and the pixel electrode 654 to partially overlap the periphery of the pixel electrode 654. A capacitor electrode 639A working with the shown pixel electrode 654 is formed with the scan line 601A and partially overlaps the pixel electrode 654, so as to prevent light leakage between the scan line 601A and the pixel electrode 654. A complementary shielding structure, for example, composed of complementary shielding layer 639B contacting the scan line 601B is formed between the scan line 601B and the pixel electrode 654 to prevent light leakage therebetween. Another complementary shielding layer 639A is formed to prevent light leakage between the scan line 601A and the upper pixel electrode 654 of which only parts are shown.
The complementary shielding structure also can be an isolated structure overlapping the pixel electrode 654 and the scan line 601B.
As shown in
The complementary shielding layers 639A and 639B are complementary in the context that they are designed to overlap certain fishbone-shaped spacings in a main shielding structure 659 formed in the upper substrate 662.
The upper substrate 662 comprises the transparent common electrode 663, the main shielding structure 659 and the color filter 660 of R (red), G (green) and B (blue), which are the three primary colors. In
The main shielding structure 659 disposed on the transparent substrate 658 is shown in
Now turning to a pixel area shown in
For example, the stripe shielding layers 651A and 651B and the complementary shielding layers 639A and 639B are formed with the scan lines 601A and 601B and from a first metal layer (M1), and the signal lines 600A and 600B and the upper capacitor electrodes 606 are formed from a second metal layer (M2). After the stripe shielding layers 651A and 651B, the complementary shielding layers 639A and 639B, the bottom electrode of the capacitor 605 and the scan lines 601A and 601B are formed in the first metal layer (M1), an insulating layer 655, such as silicon nitride, silicon oxide or the same, is deposited thereon, covering the first metal layer (M1). The signal lines 600A and 600B and the upper electrode 606 of the capacitor 605 are then formed in the second metal layer (M2) deposited on the insulating layer 655. A passivation layer 650, such as silicon nitride, silicon oxide or the same, is then formed before forming the pixel electrode 654.
Now turning to several pixel areas shown in
The main shielding structure 659 allows transmission of light passing through the pixel electrode 654 and operates in combination with stripe shielding layers 651, the complementary shielding layers 639 to block light that does not pass through the corresponding pixel electrode 654.
Third Embodiment
As shown in
Referring to
If the gaps 708S in the main shielding structure 759 are disposed over the scan lines 701 and the capacitor 705, the complementary shielding layers 739 are disposed under the main shielding structure 759, for example, the complementary shielding layers 739 extend from the scan lines 701 to block the light passing through the gaps 708S.
If the gaps 708S in the main shielding structure 759 are disposed over the signal lines 700, the complementary shielding structure, such as complementary shielding layers 709 and 719 extending from the stripe-shaped shielding layers 751 and the signal lines 700 respectively, are disposed under the main shielding structure 759 to block the light passing through the gaps 708S.
Fourth Embodiment
In the fourth embodiment a specific example of an in-plane switching mode liquid crystal display (IPS-LCD) having the characteristic of wide viewing angle is given, and a detailed description is given hereinafter.
A common electrode 863a and a data electrode 854 are formed in the pixel area. The common electrode 863a is formed with the gate electrode G and connected to the common electrode line 863b. The date electrode 854 is formed with the source/drain electrode 817 and electrically connected to the source/drain electrode 817. Further, a passivation layer 818 and a lower alignment layer 820 are deposited on the whole surface of the lower transparent substrate 856.
On an upper transparent substrate 858, a main shielding structure 859 is formed to prevent light leakage generated around the TFT, the signal lines 800 and the scan line 801. Within the pixel area, a main spacing 808L and two gaps 808S define the main shielding structure 859 and several sub-structures, in which the gaps 808S are disposed over the common electrode line 863b to block the light passing through the gaps 808S. Put simply, the complementary shielding structure used to block the light passing through the gaps 808S is the body of the common electrode line 863b and is formed with opaque material. Therefore, no additional auxiliary structure is required to block the passing light.
These gaps 808S provide a space to prevent stress across the entire LCD panel, thus preventing peeling in the color filter layer 860, formation of which is described in the following.
A color filter layer 860, and an upper alignment layer 864 are formed on the main shielding structure 859 in sequence. Also, a liquid crystal layer 857 is formed between the lower substrate 861 and the upper substrate 862.
The foregoing description of the preferred embodiments of this invention has been presented for purposes of illustration and description. Obvious modifications or variations are possible in light of the above teaching. The embodiments are chosen and described to provide the best illustration of the principles of this invention and its practical application to thereby enable those skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
Number | Name | Date | Kind |
---|---|---|---|
5251049 | Sato et al. | Oct 1993 | A |
5561440 | Kitajima et al. | Oct 1996 | A |
6034749 | Sato et al. | Mar 2000 | A |
6064358 | Kitajima et al. | May 2000 | A |
6297862 | Murade | Oct 2001 | B1 |
6424394 | Morii | Jul 2002 | B1 |
6556265 | Murade | Apr 2003 | B1 |
6610997 | Murade | Aug 2003 | B2 |
6791647 | Kim et al. | Sep 2004 | B1 |
20010019384 | Murade | Sep 2001 | A1 |
Number | Date | Country | |
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20050007524 A1 | Jan 2005 | US |