TWI845025B - Display device - Google Patents

Abstract

A display device including a substrate, a cholesteric liquid crystal layer and a transparent electrode layer, which are sequentially stacked, is provided. The cholesteric liquid crystal layer includes cholesteric liquid crystal molecules and a plurality of transparent photoresist structures. Each transparent photoresist structure is a closed structure and the cholesteric liquid crystal molecules are respectively accommodated in a plurality of patterned regions respectively surrounded by the plurality of transparent photoresist structures, so as to form a plurality of cholesteric liquid crystal patterns. The transparent electrode layer includes a plurality of sub electrodes. The plurality of cholesteric liquid crystal patterns are respectively driven by the plurality of sub electrodes. A vertical projection of each transparent photoresist structure onto the substrate falls in a vertical projection of the corresponding sub electrode onto the substrate.

Description

Display device

The present invention relates to a display device.

Cholesterol liquid crystal is a bi-stable liquid crystal molecule that can reflect circularly polarized light with a wavelength equal to its helical pitch, so it can be used to present decorative patterns. Display devices currently on the market, for example, configure cholesterol liquid crystal layers in the form of an array structure, where each pattern is composed of multiple pixels, and the decorative pattern can be switched on or off by controlling the voltage of the pixel electrode.

As shown in FIG1 , the display device 1A includes a cholesterol liquid crystal layer 300A, which forms a plurality of pixels in a periodic array form, and controls the cholesterol liquid crystal molecules in each pixel by a switching element (such as a thin film transistor) to provide a plurality of cholesterol liquid crystal patterns DP. However, such an array structure is complex, resulting in high manufacturing costs and environmental disadvantages. Therefore, a low-cost and environmentally friendly cholesterol liquid crystal display device is urgently needed.

The present invention provides a display device that does not require a complex array structure to switch the presence or absence of a decorative pattern, is low-cost and environmentally friendly.

According to an embodiment of the present invention, a display device is provided, comprising a lower substrate, a lower transparent electrode layer, a cholesterol liquid crystal layer, an upper transparent electrode layer and an upper substrate stacked in sequence. The cholesterol liquid crystal layer comprises cholesterol liquid crystal molecules and a plurality of transparent photoresist structures, each of which is a closed structure, and the cholesterol liquid crystal molecules are respectively accommodated in a plurality of patterned regions formed by the plurality of transparent photoresist structures to form a plurality of cholesterol liquid crystal patterns. The upper transparent electrode layer is a patterned electrode layer and comprises a plurality of sub-electrodes. The lower transparent electrode layer is configured as a common electrode. The plurality of cholesterol liquid crystal patterns are driven by the plurality of sub-electrodes respectively, and the vertical projection of each transparent photoresist structure on the lower substrate falls within the vertical projection of the corresponding sub-electrode on the lower substrate.

According to another embodiment of the present invention, a display device is provided, comprising a lower substrate, a lower transparent electrode layer, a cholesterol liquid crystal layer, an upper transparent electrode layer and an upper substrate stacked in sequence. The cholesterol liquid crystal layer comprises cholesterol liquid crystal molecules and a plurality of transparent photoresist structures, each of which is a closed structure, and the cholesterol liquid crystal molecules are respectively accommodated in a plurality of patterned regions formed by the plurality of transparent photoresist structures to form a plurality of cholesterol liquid crystal patterns. The upper transparent electrode layer is a patterned electrode layer and comprises a plurality of first sub-electrodes and a plurality of second sub-electrodes. The plurality of first sub-electrodes and the plurality of second sub-electrodes are staggered to form a plurality of mutual induction capacitors. The lower transparent electrode layer is configured as a common electrode. The plurality of cholesterol liquid crystal patterns are driven by the plurality of first sub-electrodes respectively, and the vertical projection of each transparent photoresist structure on the lower substrate falls within the vertical projection of the corresponding first sub-electrode on the lower substrate.

Based on the above, the display device provided by the embodiment of the present invention uses multiple transparent photoresist structures to define multiple cholesterol liquid crystal patterns, and uses multiple sub-electrodes of the transparent electrode layer to drive the multiple cholesterol liquid crystal patterns respectively. The structure of the cholesterol liquid crystal layer is simple, does not require a complex array structure, and the decorative pattern can be switched. Compared with the known display device with switchable decorative patterns, the display device provided by the embodiment of the present invention has low manufacturing cost and is environmentally friendly.

In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings.

Referring to Fig. 2A, Fig. 2B, Fig. 2C and Fig. 2D. The display device 1 provided by the embodiment of the present invention can display a cholesterol liquid crystal pattern (decorative pattern) DP _i and comprises a lower substrate 10, a lower transparent electrode layer 100, a cholesterol liquid crystal layer 300, an upper transparent electrode layer 200 and an upper substrate 20 which are sequentially stacked. The cholesterol liquid crystal layer 300 comprises cholesterol liquid crystal molecules CLC and a plurality of transparent photoresist structures 300W. The lower transparent electrode layer 100 is configured as a common electrode.

In some embodiments, as shown in FIG. 2B and FIG. 2C , the transparent photoresist structure 300W and the cholesterol liquid crystal molecules CLC can be configured by a spraying process. Each transparent photoresist structure 300W forms a closed structure on the XY plane, and the closed structure surrounds a patterned area PA. Since the transparent photoresist structure 300W is manufactured by a spraying process, the shape of the patterned area PA can be designed according to demand. Therefore, different transparent photoresist structures 300W can be used to form patterned areas PA of different shapes. The cholesterol liquid crystal molecules CLC are accommodated in different patterned areas PA to form a plurality of cholesterol liquid crystal patterns DP _i . When the cholesterol liquid crystal molecules CLC in the patterned area PA are in a planar state, the cholesterol liquid crystal pattern DP _i is displayed and is visible. When the cholesterol liquid crystal molecules CLC in the patterned area PA are in a focal conic state, the cholesterol liquid crystal pattern DP _i is not displayed and is invisible.

In some embodiments, the transparent photoresist structure 300W may also be hydrophobic to reduce the adhesion of the cholesterol liquid crystal molecules CLC on the transparent photoresist structure 300W. In addition to the physical restrictions caused by the surrounding of the transparent photoresist structure 300W, the cholesterol liquid crystal molecules CLC can be further restricted in the patterned area PA formed by the transparent photoresist structure 300W because their own cohesive force is greater than the above-mentioned adhesion force, thereby preventing the cholesterol liquid crystal molecules CLC from leaking out of the transparent photoresist structure 300W.

The upper transparent electrode layer 200 is a patterned electrode layer and includes a plurality of sub-electrodes. In some embodiments, the sub-electrodes corresponding to different cholesterol liquid crystal patterns DP _i are electrically connected to each other. However, the present invention is not limited thereto. In some embodiments, the sub-electrodes corresponding to different cholesterol liquid crystal patterns DP _i are electrically insulated from each other.

Specifically, please refer to FIG. 2A and FIG. 2D at the same time. In one embodiment, FIG. 2D is a cross-sectional schematic diagram along line segment Ⅰ-Ⅰ' of FIG. 2A. Different cholesterol liquid crystal patterns DP _i (letters D and E in FIG. 2A) correspond to the same sub-electrode of the upper transparent electrode layer 200, or correspond to sub-electrodes electrically connected to each other. In this case, these different cholesterol liquid crystal patterns DP _i (letters D and E in FIG. 2A) can be displayed at the same time or not displayed at the same time.

In contrast, in one embodiment, FIG. 2D is a cross-sectional schematic diagram along line segment II-II' of FIG. 2A, where one sub-electrode corresponds to only one cholesterol liquid crystal pattern DP _i (letter G in FIG. 2A), and different cholesterol liquid crystal patterns DP _i (letters A, B, C, D, E, F, and G in FIG. 2A) correspond to different sub-electrodes, respectively, and different sub-electrodes are electrically insulated. In this case, these cholesterol liquid crystal patterns DP _i (letters A, B, C, D, E, F, and G in FIG. 2A) can be independently driven by different sub-electrodes to display or not display.

It should be particularly noted that, as shown in FIG2D , the vertical projections of each transparent photoresist structure 300W and the cholesterol liquid crystal pattern DP _i formed therearound on the lower substrate 10 all fall within the vertical projections of the corresponding sub-electrodes on the lower substrate 10, so as to ensure the integrity of the pattern when each cholesterol liquid crystal pattern DP _i (English letters A, B, C, D, E, F and G in FIG2A ) is displayed, and to avoid defects in the shape of the pattern, such as gaps or cracks in the pattern, caused by the sub-electrode being too small in area or not completely covering the transparent photoresist structure 300W and the cholesterol liquid crystal pattern DP _i . In some embodiments, the vertical projection of each transparent photoresist structure 300W and the cholesterol liquid crystal pattern DP _i formed therearound on the lower substrate 10 falls within the vertical projection of the corresponding sub-electrode on the lower substrate 10 and is smaller than the vertical projection of the corresponding sub-electrode on the lower substrate 10 .

In order to fully illustrate various embodiments of the present invention, other embodiments of the present invention will be described below. It must be noted that the following embodiments use the component numbers and some contents of the previous embodiments, wherein the same numbers are used to represent the same or similar components, and the description of the same technical contents is omitted. The description of the omitted parts can refer to the previous embodiments, and the following embodiments will not be repeated.

3, compared with the above-mentioned embodiments, the display device 2 provided in some embodiments of the present invention may further include a display panel 30 disposed below the lower substrate 10. In other words, the display device 1 is disposed on the display panel 30 to form the display device 2. The display device 2 can simultaneously display the cholesterol liquid crystal pattern DP _i of the display device 1 and the image of the display panel 30.

Referring to FIG. 4A, FIG. 4B and FIG. 4C, FIG. 4C is a partial cross-sectional schematic diagram of line segment III-III' in FIG. 4B. Compared with the display device 1, the lower substrate 10F and the upper substrate 20F of the display device 3 are both flexible substrates. Therefore, the display device 3 can be configured on the object surface 50, and the object surface 50 can be a curved surface. In addition, the upper transparent electrode layer 200 is a patterned electrode layer, and includes a plurality of discrete sub-electrodes 200_1, 200_2, 200_3 ... 200_N, which are insulated from each other, and each sub-electrode 200_1, 200_2, 200_3 ... 200_N corresponds to only one cholesterol liquid crystal pattern DP _i .

In this embodiment, different cholesterol liquid crystal patterns DP _i are driven by different sub-electrodes 200_1, 200_2, 200_3 ... 200_N. Using the self-inductance capacitance sensing method, the sub-electrodes 200_1, 200_2, 200_3 ... 200_N are touch electrodes, and are connected to the driving and sensing circuits H_1, H_2, H_3 ... H_N through different wires. When a finger touches the display device 3, a sufficiently large coupling capacitance is generated between the sub-electrode 200_1, 200_2, 200_3 ... or 200_N and the finger. The capacitance change value measured by the sub-electrodes 200_1, 200_2, 200_3, ... or 200_N is used to infer which cholesterol liquid crystal pattern DP _i the user has clicked.

5A to 5E , FIG. 5B may be, for example, a partial cross-sectional schematic diagram along the line connecting the English letters T and Y in FIG. 5A .

The upper transparent electrode layer 200 of the display device 4 is a patterned electrode layer, and includes a plurality of discrete sub-electrodes 201 and a plurality of discrete sub-electrodes 202. In addition to driving the cholesterol liquid crystal pattern DP _i , the plurality of sub-electrodes 201 and the plurality of sub-electrodes 202 can also be used as touch electrodes. The display device 4 is also equipped with a protective layer 40 for user touch.

Specifically, a plurality of discrete sub-electrodes 201 are arranged along the Y direction and are respectively connected to driving circuits X1 to X4, and a plurality of discrete sub-electrodes 202 are arranged along the X direction and are respectively connected to sensing circuits Y1 to Y10. Using the mutual induction capacitance method, in the first half of a time cycle, the plurality of discrete sub-electrodes 201 are sequentially driven by driving circuits X1 to X4, so that a plurality of capacitors formed by the sub-electrodes 201 and the sub-electrodes 202 adjacent to each other are charged. In the second half of the same time cycle, the voltages on the plurality of discrete sub-electrodes 202 are sequentially sensed by sensing circuits Y1 to Y10 to obtain 4×10 data. Therefore, when the user selects a cholesterol liquid crystal pattern DP _i on the display device 4 with a finger, the user can know which cholesterol liquid crystal pattern DP _i is selected through the 4×10 data.

It should be noted that this embodiment only illustrates 4 discrete sub-electrodes 201 and 4 corresponding driving circuits X1-X4, and only illustrates 10 discrete sub-electrodes 202 and 10 corresponding sensing circuits Y1-Y10, but the number of these components is not limited thereto.

It should be noted that, compared to the display device 3, the single sub-electrode 201 of the display device 4 can be used to drive multiple cholesterol liquid crystal patterns DP _i . For example, in FIG. 5A , multiple cholesterol liquid crystal patterns DP _i (numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 0) are driven by the same sub-electrode 201. For another example, multiple cholesterol liquid crystal patterns DP _i (English letters A, S, D, F, G, H, J, K, L) are driven by the same sub-electrode 201. The main reason why a single sub-electrode 201 of the display device 4 can be configured to drive multiple cholesterol liquid crystal patterns DP _i at the same time is that, through the above-mentioned mutual induction capacitance method, the display device 4 can know which cholesterol liquid crystal pattern DP _i the user has clicked based on 4×10 data. This enables the display device 4 to provide more complex decorative patterns compared to the display device 3. As shown in FIG. 5C , the display device 4 can use multiple cholesterol liquid crystal patterns DP _i to display more complex information.

It should be noted that in other embodiments, multiple cholesterol liquid crystal patterns DP _i can also be driven by multiple sub-electrodes 202, or a portion of the cholesterol liquid crystal pattern DP _i is driven by some sub-electrodes 201 and the remaining other cholesterol liquid crystal patterns DP _i are driven by some sub-electrodes 202, and is not limited to the configuration of Figure 5A.

Referring to FIG. 5C , FIG. 5D and FIG. 5E , when the display device 4 is to be switched from a state without decorative patterns (as shown in the left figure of FIG. 5C ) to a state with decorative patterns (as shown in the right figure of FIG. 5C ), the voltage applied to the sub-electrode 201 may be as shown in FIG. 5D . Specifically, in the first stage, a high voltage V1 (e.g., 30V to 50V) is applied to make the cholesterol liquid crystal molecules in a transient state (Homeotropic state, vertical state); in the second stage, a low voltage V2 (e.g., 0V) is applied to make the cholesterol liquid crystal molecules in a planar state (Planar state) to display the decorative patterns; and in the third stage, a low voltage V3 (e.g., 5V to 10V) is applied to maintain the cholesterol liquid crystal molecules in a planar state and the upper transparent electrode layer 200 can provide a touch function.

In contrast, when the display device 4 is to be switched from the state with the decorative pattern (as shown in the right figure of FIG. 5C ) to the state without the decorative pattern (as shown in the left figure of FIG. 5C ), the voltage applied to the sub-electrode 201 may be as shown in FIG. 5E . Specifically, in the first stage, the cholesterol liquid crystal molecules are in a planar state, and the voltage V1 of the sub-electrode 201 is 0V; in the second stage, a higher voltage V2 (e.g., 15V~20V) is applied; and in the third stage, the voltage V3 of the sub-electrode 201 is reduced to 0V to maintain the cholesterol liquid crystal molecules in a focal conical state.

In summary, the display device provided by the embodiment of the present invention uses multiple transparent photoresist structures to define multiple cholesterol liquid crystal patterns, and uses multiple sub-electrodes of the transparent electrode layer to drive the multiple cholesterol liquid crystal patterns respectively. The structure of the cholesterol liquid crystal layer is simple, does not require a complex array structure, and the decorative pattern can be switched. Compared with the known display device with switchable decorative patterns, the display device provided by the embodiment of the present invention has low manufacturing cost and is environmentally friendly.

1, 2, 3, 4: display device 10, 10F: lower substrate 20, 20F: upper substrate 30: display panel 50: surface 100: lower transparent electrode layer 200: upper transparent electrode layer 200_1, 200_2, 200_3...200_N, 201, 202: sub-electrode 300: cholesterol liquid crystal layer 300W: transparent photoresist structure CLC: cholesterol liquid crystal molecule DP _i : cholesterol liquid crystal pattern H_1, H_2, H_3...H_N: driving and sensing circuit PA: patterned area V1, V2, V3: voltage X1~X4: driving circuit X, Y, Z: direction Y1~Y10: sensing circuit

FIG. 1 is a schematic diagram of a display device according to a comparative example. FIG. 2A is a schematic diagram of a display device according to an embodiment of the present invention. FIG. 2B and FIG. 2C are schematic diagrams of a method for manufacturing a display device according to an embodiment of the present invention. FIG. 2D is a partial cross-sectional schematic diagram of the display device of FIG. 2A. FIG. 3 is a schematic diagram of a display device according to an embodiment of the present invention. FIG. 4A is a schematic diagram of a display device according to an embodiment of the present invention. FIG. 4B is a schematic diagram of the display device of FIG. 4A in an application. FIG. 4C is a partial cross-sectional schematic diagram of FIG. 4B. FIG. 5A is a schematic diagram of a display device according to an embodiment of the present invention. FIG. 5B is a partial cross-sectional schematic diagram of the display device of FIG. 5A. FIG. 5C is a schematic diagram of a display device according to an embodiment of the present invention. FIG. 5D is a schematic diagram of a driving voltage of a display device according to an embodiment of the present invention. FIG. 5E is a schematic diagram of a driving voltage of a display device according to an embodiment of the present invention.

10: Lower substrate 100: Lower transparent electrode layer 300: Cholesterol liquid crystal layer 300W: Transparent photoresist structure CLC: Cholesterol liquid crystal molecules DP _i : Cholesterol liquid crystal pattern X, Y, Z: Directions

Claims (10)

A display device comprises a lower substrate, a lower transparent electrode layer, a cholesterol liquid crystal layer, an upper transparent electrode layer and an upper substrate which are sequentially stacked, wherein the cholesterol liquid crystal layer comprises cholesterol liquid crystal molecules and a plurality of transparent photoresist structures, each of the transparent photoresist structures is a closed structure and is independent of each other, and the cholesterol liquid crystal molecules are respectively accommodated in a plurality of patterned regions formed by the plurality of transparent photoresist structures to form a plurality of cholesterol liquid crystal patterns, and the upper transparent electrode layer comprises a cholesterol liquid crystal molecule and a plurality of transparent photoresist structures. The electrode layer is a patterned electrode layer and includes a plurality of sub-electrodes. The plurality of cholesterol liquid crystal patterns are driven by the plurality of sub-electrodes respectively, whereby when the cholesterol liquid crystal molecules are in a planar state, the upper transparent electrode layer provides a touch function, the lower transparent electrode layer is configured as a common electrode, and each of the transparent photoresist structures and the cholesterol liquid crystal pattern formed by the structure on the lower substrate have vertical projections that completely fall within the vertical projections of the corresponding sub-electrodes on the lower substrate. A display device as described in claim 1, wherein each of the sub-electrodes corresponds to only one of the multiple cholesterol liquid crystal patterns. A display device as described in claim 1, wherein the vertical projection of each transparent photoresist structure on the lower substrate is smaller than the vertical projection of the corresponding sub-electrode on the lower substrate. A display device comprises a lower substrate, a lower transparent electrode layer, a cholesterol liquid crystal layer, an upper transparent electrode layer and an upper substrate which are sequentially stacked, wherein the cholesterol liquid crystal layer comprises cholesterol liquid crystal molecules and a plurality of transparent photoresist structures, each of which is a closed structure and independent of each other, and the cholesterol liquid crystal molecules are respectively accommodated in a plurality of patterned regions formed by the plurality of transparent photoresist structures respectively surrounding each other to form a plurality of cholesterol liquid crystal patterns, the upper transparent electrode layer is a patterned electrode layer and comprises a plurality of first sub-electrodes and a plurality of second sub-electrodes. Two sub-electrodes, and the multiple first sub-electrodes and the multiple second sub-electrodes are staggered to form multiple mutual induction capacitors, the multiple cholesterol liquid crystal patterns are driven by the multiple first sub-electrodes respectively, whereby when the cholesterol liquid crystal molecules are in a planar state, the upper transparent electrode layer provides a touch function, the lower transparent electrode layer is configured as a common electrode, and each of the transparent photoresist structures and the cholesterol liquid crystal pattern formed by it on the lower substrate completely fall within the vertical projection of the corresponding first sub-electrode on the lower substrate. A display device as described in claim 4, wherein the vertical projection of each transparent photoresist structure on the lower substrate is smaller than the vertical projection of the corresponding first sub-electrode on the lower substrate. A display device as described in claim 1 or 4, wherein the plurality of transparent photoresist structures are hydrophobic. A display device as described in claim 1 or 4, wherein the upper substrate and the lower substrate are flexible substrates. The display device as described in claim 1 or 4 further includes a display panel, wherein the lower substrate is disposed between the display panel and the upper substrate. In the display device as described in claim 4, the multiple first sub-electrodes are respectively connected to multiple driving circuits, and the multiple second sub-electrodes are respectively connected to multiple sensing circuits. A display device as described in claim 4, wherein the multiple cholesterol liquid crystal patterns are driven by the same one of the multiple first sub-electrodes.

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