Pixel structure, display panel and operation method thereof

A pixel structure including an element region and a viewing angle adjustment region is provided. The pixel structure includes a scan line, a first data line, a second data line, a first active element, a second active element, a planarization layer, and a reflective electrode. The first active element is electrically connected to the scan line and the first data line. The second active element is electrically connected to the scan line and the second data line. The reflective electrode is disposed on the planarization layer and electrically connected to the second active element. The reflective electrode has a fixed portion located in the element region and a cantilever portion located in the viewing angle adjustment region. The cantilever portion is connected to the fixed portion and is suspended. A display panel and an operation method of the display panel are also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 105141522, filed on Dec. 15, 2016. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

FIELD OF THE INVENTION

The invention relates to a pixel structure, a display panel and an operation method thereof. More particularly, the invention relates to a pixel structure with an adjustable viewing angle, a display panel, and an operation method thereof.

DESCRIPTION OF RELATED ART

Color washout easily occurs in a conventional display panel (e.g., a transmissive display panel) when the conventional display panel is placed outdoor or irradiated by strong light, leading to a reduction of contrast and a decrease in display quality. In addition, when a viewing angle of a user changes, for example, when the viewing angle is tilted up, down, to the left, or to the right, a brightness, a contrast, or color of a screen is likely to be shifted, resulting in distortion or color shift. A contrast ratio of 10:1 is generally defined by the industry as the limit of the viewing angle. At present, methods for improving the viewing angle mainly emphasize on how to increase the viewing angle (i.e., expanding a range of the viewing angle). However, when a placement angle of the display panel is changed, the methods may still not be able to effectively prevent the user from seeing the images with distortion or color shift.

SUMMARY OF THE INVENTION

The invention provides a pixel structure, a display panel and an operation method thereof suitable for fixing problems such as image distortion or color shift resulting from a change of a placement angle.

In an embodiment of the invention, a pixel structure has an element region and a viewing angle adjustment region. The pixel structure is disposed on a substrate and includes a scan line, a first data line, a second data line, a first active element, a second active element, a planarization layer, and a reflective electrode. The first data line and the second data line intersect with the scan line, respectively. The first active element is located in the element region and electrically connected to the scan line and the first data line. The second active element is located in the element region and electrically connected to the scan line and the second data line. The planarization layer covers the scan line, the first data line, the second data line, the first active element, and the second active element. The reflective electrode is disposed on the planarization layer and electrically connected to the second active element. The reflective electrode has a fixed portion located in the element region and a cantilever portion located in the viewing angle adjustment region. The cantilever portion is connected to the fixed portion, and the cantilever portion is suspended.

In an embodiment of the invention, a display panel includes a plurality of the pixel structures, an opposite substrate, and a display medium. The pixel structures are disposed on the substrate. The opposite substrate is opposite to the substrate. The display medium is disposed between the substrate and the opposite substrate.

In an embodiment of the invention, an operation method of the display panel includes following steps. The display panel is provided. Whether a placement angle of the display panel is changed is detected. A change of the placement angle is calculated if the placement angle is changed. A warping angle of the cantilever portion is changed according to the change of the placement angle of the display panel.

In view of the foregoing, a control signal may be dynamically fed back to the cantilever portion according to the change of the placement angle of the display panel, so as to adjust the warping angle of the cantilever portion and thereby dynamically adjust the viewing angle. Hence, the pixel structure, the display panel and the operation method thereof provided in the embodiments of the invention are suitable for fixing problems such as image distortion or color shift resulting from the change of the placement angle.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1Ais a schematic top view of a pixel structure according to a first embodiment of the invention.FIG. 1BandFIG. 1Care respectively schematic cross-sectional views of the pixel structure inFIG. 1A.FIG. 1Dis a schematic cross-sectional view illustrating a warped cantilever portion corresponding toFIG. 1B.

Referring toFIG. 1AtoFIG. 1C, a pixel structure100provided in the embodiment has an element region A1and a viewing angle adjustment region A2. The viewing angle adjustment region A2is located at a side of the element region A1and connected to the element region A1. The pixel structure100is disposed on a substrate SUB and includes a scan line110, a first data line120, a second data line130, a first active element140, a second active element150, a planarization layer160, and a reflective electrode170.

The first data line120and the second data line130intersect with the scan line110, respectively. In the embodiment, the scan line110is extended along a first direction D1, and the first data line120and the second data line130are respectively extended along a second direction D2. The second direction D2and the first direction D1intersect with each other, for example, perpendicular to each other, but the invention is not limited thereto.

The first active element140is located in the element region A1and electrically connected to the scan line110and the first data line120. The second active element150is located in the element region A1and electrically connected to the scan line110and the second data line130. Furthermore, the first active element140and the second active element150may respectively include a gate electrode GE, a gate insulation layer GI, a channel layer CH, a source electrode SE, and a drain electrode DE. The gate insulation layer GI is disposed on the gate electrode GE as well as on the substrate SUB. The channel layer CH is disposed on the gate insulation layer GI and is located above the gate electrode GE. The source electrode SE and the drain electrode DE are located on the gate insulation layer GI and respectively extended to opposite sides of the channel layer CH, such that partial regions of the gate insulation layer GI are respectively covered. However, the stacking orders of film layers of the first active element140and the second active element150are not limited thereto.

The gate electrode GE of the first active element140and the gate electrode GE of the second active element150are electrically connected to the scan line110. The source electrode SE of the first active element140is electrically connected to the first data line120, and the source electrode SE of the second active element150is electrically connected to the second data line130. In the embodiment, the scan line110, the gate electrode GE of the first active element140, and the gate electrode GE of the second active element150are, for example, collectively formed by patterning a first conductive layer, while the first data line120, the second data line130, the source electrode SE of the first active element140, and the source electrode SE of the second active element150are, for example, formed by patterning a second conductive layer, but the invention is not limited thereto.

The planarization layer160covers the scan line110, the first data line120, the second data line130, the first active element140, and the second active element150. For instance, the planarization layer160is, for example, an organic insulation layer, but the invention is not limited thereto. In the embodiment, the pixel structure100may alternatively include an insulation layer180. The scan line110, the first data line120, the second data line130, the first active element140, and the second active element150may be sequentially covered by the insulation layer180and the planarization layer160. The insulation layer180may be an inorganic insulation layer to achieve water-resistant and antioxidant effects.

The reflective electrode170is disposed on the planarization layer160and electrically connected to the second active element150. Specifically, the planarization layer160and the insulation layer180may be formed with a through hole TH. A portion region of the drain electrode DE of the second active element150is exposed by the through hole TH, and the reflective electrode170may be electrically connected to the drain electrode DE of the second active element150through the through hole TH. In the embodiment, as shown inFIG. 1, the first data line120and the second data line130are respectively located on opposite sides of the reflective electrode170, but the invention is not limited thereto. The first data line120and the second data line130may also be located on the same side of the reflective electrode170according to different design requirements.

The reflective electrode170has a fixed portion172located in the element region A1and a cantilever portion174located in the viewing angle adjustment region A2. The cantilever portion174is connected to the fixed portion172, and the cantilever portion174is suspended. Specifically, a gap G exists between the cantilever portion174and the planarization layer160, meaning that the cantilever portion174and the planarization layer160are separated from each other. Therefore, the cantilever portion174is able to swing (warp) when a connection part between the cantilever portion174and the fixed portion172acts as a swing axle.

In the embodiment, as shown inFIG. 1D, the drain electrode DE of the first active element140is extended into the viewing angle adjustment region A2from the element region A1, and a warping angle θ of the cantilever portion174is changed according to a mutual repulsion between the cantilever portion174and the drain electrode DE of the first active element140. Furthermore, when the warping angle θ of the cantilever portion174is required to be changed, a control signal may be outputted to the drain electrode DE of the first active element140and the cantilever portion174, and thereby the mutual repulsion (e.g., a magnetic repulsion force) is generated between the drain electrode DE of the first active element140and the cantilever portion174. The cantilever portion174is therefore warped. If the warping angle θ of the cantilever portion174is adjusted whenever necessary according to the placement angle of a mobile apparatus, the viewing angle may thus be expanded effectively and instantaneously, and problems, such as image distortion or color shift resulting from the change of the placement angle, may thereby be resolved.

In addition, a turning portion C between the fixed portion172and the cantilever portion174may be designed as a rounded corner, so as to prevent stress concentration and obtain the desired lifetime.

FIG. 2AtoFIG. 2Dare schematic cross-sectional views illustrating a process for fabricating the reflective electrode inFIG. 1B. After the planarization layer160is formed, a sacrificial layer L1and a photoresist layer L2may be sequentially formed on the planarization layer160(as shown inFIG. 2A). Next, the photoresist layer L2is patterned to form a patterned photoresist layer L2′ (as shown inFIG. 2B). A method of patterning the photoresist layer L2may include etching, but the invention is not limited thereto. The patterned photoresist layer L2′ is then used as a mask to pattern the sacrificial layer L1, such that a patterned sacrificial layer L1′ is formed (as shown inFIG. 2C). A method of patterning the sacrificial layer L1may include etching, but the invention is not limited thereto. Thereafter, the reflective electrode170is formed on the planarization layer160and the patterned sacrificial layer L1′ (as shown inFIG. 2D). The patterned sacrificial layer L1′ is removed, and the fabrication of the reflective electrode170is completed.

It should be noted that the method of fabricating the reflective electrode170is not limited to the fabrication process shown inFIG. 2AtoFIG. 2D. In another embodiment, the reflective electrode170may also be formed through electroforming and embossing. Specifically, a male mold pattern may be formed on a roller in advance, and then the male mold pattern is impressed on a sacrificial layer to form a female mold of the reflective electrode170. The female mold of the reflective electrode170is then filled with the material of the reflective electrode, so as to complete the fabrication of the reflective electrode170.

The pixel structure100is described in other embodiments with reference toFIG. 3AtoFIG. 3C, and identical or similar elements are denoted by the same or similar reference numerals, which will not be described again hereinafter.FIG. 3Ais a schematic top view of a pixel structure according to a second embodiment of the invention.FIG. 3BandFIG. 3Care respectively schematic cross-sectional views of the pixel structure inFIG. 3A.

Referring toFIG. 3AtoFIG. 3C, differences between a pixel structure100A in the embodiment and the pixel structure100inFIG. 1AtoFIG. 1Dare described below. In the pixel structure100A, the viewing angle adjustment region A2has a reflective region A21and a transmissive region A22. The transmissive region A22is connected to the reflective region A21, and the reflective region A21is located between the transmissive region A22and the element region A1. The cantilever portion174is located in the reflective region A21and exposes the transmissive region A22.

In addition, the pixel structure100A further includes a pixel electrode190. The pixel electrode190is electrically connected to the first active element140and extended into the transmissive region A22from the reflective region A21. Specifically, the pixel electrode190is disposed on an insulation layer180. The insulation layer180may be formed with an opening O. A portion of the drain electrode DE of the first active element140is exposed by the opening O, and the pixel electrode190may be electrically connected to the drain electrode DE of the first active element140through the opening O.

In the embodiment, when the warping angle of the cantilever portion174is required to be changed, the control signal may be outputted to the pixel electrode190and the cantilever portion174, and the warping angle of the cantilever portion174is thereby changed according to a mutual repulsion (e.g., a magnetic repulsion force) generated between the cantilever portion174and the pixel structure190. If the warping angle of the cantilever portion174is adjusted whenever necessary according to the placement angle of the mobile apparatus, the viewing angle may be expanded effectively and instantaneously, and problems, such as image distortion or color shift resulting from the change of the placement angle, may thereby be resolved.

FIG. 4is a schematic cross-sectional view of a display panel according to an embodiment of the invention. Referring toFIG. 4, a display panel10in the embodiment includes a plurality of the pixel structures100(only one pixel structure100is schematically illustrated inFIG. 4), an opposite substrate200, and a display medium300. The pixel structure100is disposed on the substrate SUB. The opposite substrate200is opposite to the substrate SUB. The display medium300is disposed between the substrate SUB and the opposite substrate200. The display medium300is, for example, a liquid crystal layer, but the invention is not limited thereto.

In this embodiment, the display panel10is, for example, a reflective display panel, but the invention is not limited thereto. In another embodiment, a plurality of the pixel structures100A as shown inFIG. 3AtoFIG. 3Cmay be adopted by the display panel10, such that the display panel10may be a transflective display panel.

FIG. 5is a schematic flow chart of an operation method of a display panel according to an embodiment of the invention. The operation method of the display panel in the embodiment includes following steps. Referring toFIG. 1D, FIG.4, andFIG. 5, first, the display panel10is provided (step S100). The display panel10may be constructed in a mobile apparatus, but the invention is not limited thereto. Next, whether a placement angle of the display panel10is changed is detected (step S110); for example, a G-sensor constructed in the mobile apparatus may be applied to detect whether the placement angle of the display panel10is changed. When the mobile apparatus is tilted, the display panel10and the G-sensor located in the mobile apparatus are also tilted, and thereby whether the placement angle of the display panel10is changed and the change of the placement angle may be determined according to whether a signal is generated by the G-sensor and how strong the signal is. When the placement angle of the display panel10is changed, the change of the placement angle of the display panel10is calculated (step S120); for example, the change of the placement angle may be calculated through a microcontroller unit constructed in the mobile apparatus according to the signal generated by the G-sensor. Next, the warping angle θ of the cantilever portion174is changed according to the change of the placement angle of the display panel10(step S130). A method of changing the warping angle θ of the cantilever portion174includes outputting the control signal to the drain electrode DE of the first active element140and the cantilever portion174through the first data line120and the second data line130. Therefore, the warping angle θ of the cantilever portion174may be changed according to the mutual repulsion between the cantilever portion174and the drain electrode DE of the first active element140(as shown inFIG. 1D). Alternately, the warping angle θ may also be changed (as shown inFIG. 3B) by the cantilever portion174according to the mutual repulsion between the cantilever portion174and the pixel electrode190(electrically connected to the drain electrode DE of the first active element140).

In view of the foregoing, the control signal may be dynamically fed back to the cantilever portion according to the change of the placement angle of the display panel, so as to adjust the warping angle of the cantilever portion and thereby dynamically adjust the viewing angle. Hence, the pixel structure, the display panel and the operation method thereof provided in the embodiments of the invention are suitable for fixing problems such as image distortion or color shift resulting from the change of the placement angle.