Electrophoretic display device

Abstract

An electrophoretic display device includes a pixel structure and a color filter array. The area of the blue pixel electrode of the pixel structure is smaller than that of the red pixel electrode, and the area of the blue pixel electrode is smaller than that of the green pixel electrode. A red filter unit, a green filter unit and a blue filter unit in the color filter array have the same area and are respectively overlapped on the red pixel electrode, the green pixel electrode and the green pixel electrode. The ratio of the area of the red filter unit to the area of the red pixel electrode is RFF; the ratio of the area of the green filtering unit to the area of the green pixel electrode is GFF; the ratio of the area of the blue filtering unit to the area of the blue pixel electrode is BFF, and BFFgt; rFF > = GFF.

Description

Technical Field

[0001] This invention relates to a display device, and more particularly to an electrophoretic display device. Background Technology

[0002] Due to their advantages such as thinness, durability, and energy efficiency, electrophoretic display devices are now widely used in e-readers (e.g., e-books, e-newspapers) and electronic shelf labels (ESLs) as environmental protection and energy conservation become increasingly important issues. Furthermore, color electrophoretic display technology, capable of displaying multiple colors, has become a focus of research and development for various manufacturers.

[0003] However, compared to backlit or self-emissive displays, reflective displays typically have dimmer light. Due to the lack of a color-emitting light source, their brightness is highly dependent on ambient lighting conditions. This makes it difficult for reflective displays to display brighter colors, such as yellow. Low color brightness and low color purity result in reduced contrast, negatively impacting the user's viewing experience. Summary of the Invention

[0004] The present invention provides an electrophoretic display device with better color contrast and color purity.

[0005] Embodiments of the present invention provide an electrophoretic display device, including a pixel structure and a color filter array. The area of ​​the blue pixel electrode in the pixel structure is smaller than the area of ​​the red pixel electrode, and the area of ​​the blue pixel electrode is smaller than the area of ​​the green pixel electrode. The areas of the red filter units, green filter units, and blue filter units in the color filter array are all the same and overlap the red pixel electrode, green pixel electrode, and green pixel electrode, respectively. The ratio of the area of ​​the red filter unit to the area of ​​the red pixel electrode is RFF; the ratio of the area of ​​the green filter unit to the area of ​​the green pixel electrode is GFF; the ratio of the area of ​​the blue filter unit to the area of ​​the blue pixel electrode is BFF, and BFF > RFF ≥ GFF.

[0006] In one embodiment of the present invention, the above-mentioned electrophoretic display device further satisfies the following conditions: RFF≤75%; GFF≤62.5%; and BFF≤93.7%.

[0007] In one embodiment of the present invention, the above-mentioned electrophoretic display device further satisfies the following conditions: RFF≤63%; GFF≤63%; and BFF≤100%.

[0008] In one embodiment of the present invention, the above-mentioned electrophoretic display device further satisfies the following conditions: RFF≤67%; GFF≤60%; and BFF≤100%.

[0009] In one embodiment of the present invention, the display surface of the electrophoretic display device described above has a first direction and a second direction perpendicular to each other, and red pixel electrodes, green pixel electrodes and blue pixel electrodes are arranged closely together. The blue pixel electrodes extend in the first direction and the second direction respectively, such that the outlines of the red pixel electrodes adjacent to the blue pixel electrodes and the outlines of the green pixel electrodes adjacent to the blue pixel electrodes both recede away from the blue pixel electrodes.

[0010] In one embodiment of the present invention, the outline of the aforementioned blue pixel electrode is cross-shaped. The two vertical ends of the cross shape extend in a first direction and a second direction, respectively.

[0011] In one embodiment of the present invention, the display surface of the electrophoretic display device described above has a first direction and a second direction perpendicular to each other, and red pixel electrodes, green pixel electrodes and blue pixel electrodes are arranged closely together. The red pixel electrodes, green pixel electrodes and blue pixel electrodes all have the same width in the first direction, and the red pixel electrodes, green pixel electrodes and blue pixel electrodes all extend in the second direction.

[0012] In one embodiment of the present invention, the red pixel electrode, green pixel electrode, and blue pixel electrode are arranged closely together, and the outline of the blue pixel electrode is substantially circular. The outlines of the red pixel electrode adjacent to the blue pixel electrode and the outlines of the green pixel electrode adjacent to the blue pixel electrode both recede away from the blue pixel electrode.

[0013] In one embodiment of the present invention, another red pixel electrode is further included, wherein a first direction and a second direction perpendicular to each other are present on the display surface of the electrophoretic display device, and the red pixel electrode and the other red pixel electrode are respectively located in the first direction and the second direction of the blue pixel electrode. The blue pixel electrode extends toward the red pixel electrode and toward the other red pixel electrode, such that the outline of the red pixel electrode adjacent to the blue pixel electrode and the outline of the other red pixel electrode both recede away from the blue pixel electrode.

[0014] In one embodiment of the present invention, the red pixel electrode, green pixel electrode and blue pixel electrode are arranged closely together, and the blue pixel electrode extends toward the red pixel electrode, such that the outline of the red pixel electrode adjacent to the blue pixel electrode recedes away from the blue pixel electrode.

[0015] In one embodiment of the present invention, the shape of the red filter unit is the same as the shape of the red pixel electrode, the shape of the green filter unit is the same as the shape of the green pixel electrode, and the shape of the blue filter unit is the same as the shape of the blue pixel electrode.

[0016] In one embodiment of the present invention, the green pixel electrode extends toward the blue pixel electrode, such that the outline of the blue pixel electrode adjacent to the green pixel electrode recedes away from the green pixel electrode.

[0017] In one embodiment of the present invention, the electrophoretic display device further includes an electrophoretic display film disposed between the pixel structure and the color filter array. The electrophoretic display film includes a microcapsule electrophoretic structure or a microcup electrophoretic structure.

[0018] Based on the above, in the embodiments of the present invention, since the areas of the green and red pixel electrodes are both larger than the area of ​​the blue pixel electrode, the green and yellow light displayed by the electrophoretic display device can be brighter, while the blue light can be darker, effectively improving the contrast and chroma of the displayed image. On the other hand, since the areas of the red, green, and blue filter units are all the same, the pixel coverage ratio (BFF) of the blue filter unit is greater than that of the green filter unit (GFF) and the red filter unit (RFF). Therefore, while adjusting the brightness of the primary color light, it is also beneficial to maintain the white balance of the electrophoretic display device, which can reduce the color shift problem of the electrophoretic display device and effectively improve the contrast and display quality of the electrophoretic display device.

[0019] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0020] The accompanying drawings are included to further illustrate the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0021] Figure 1A This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0022] Figure 1B yes Figure 1A A schematic cross-sectional view of the electrophoretic display device according to the embodiment, along section line I-I'.

[0023] Figure 2 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0024] Figure 3 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0025] Figure 4 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0026] Figure 5 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0027] Figure 6 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0028] Figure 7 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0029] Figure 8 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0030] Figure 9 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0031] Figure 10 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention;

[0032] Figure 11 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention.

[0033] Explanation of icon numbers

[0034] 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J, 10K: Electrophoresis display device;

[0035] 100:Substrate;

[0036] 110: Color filter array;

[0037] 110R: Red filter unit;

[0038] 110G: Green filter unit;

[0039] 110B: Blue filter unit;

[0040] 111: Filter substrate;

[0041] 112: Adhesive layer;

[0042] 113: Cover plate;

[0043] 120: Pixel structure;

[0044] 121: Pixel unit;

[0045] 121R,121R': Red subpixel;

[0046] 121G,121G': Green subpixel;

[0047] 121B: Blue subpixel;

[0048] 130: Electrophoretic display film;

[0049] 131: Microcapsule structure;

[0050] 132: Electrophoresis solution;

[0051] 140: Insulation layer;

[0052] B: Black charged particles;

[0053] BD1, BD: boundary;

[0054] CR,CG,CB,RR,RG,RB: Area;

[0055] e1: First end;

[0056] e2: Second end;

[0057] I-I': section line;

[0058] PR: Red pixel electrode;

[0059] PG: Green pixel electrode;

[0060] PB: Blue pixel electrode;

[0061] W: White charged particles;

[0062] X: First direction;

[0063] Y: Second direction;

[0064] Z: Third-party orientation. Detailed Implementation

[0065] The directional terms used in this document, such as "up," "down," "front," "back," "left," and "right," are only for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0066] In the accompanying drawings, the thicknesses of layers, films, panels, regions, etc., are enlarged for clarity. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected" to another element, it may be directly on or connected to the other element, or intermediate elements may also be present. Conversely, when an element is referred to as being "directly on" or "directly connected" to another element, no intermediate elements are present. As used herein, "connection" can refer to a physical and / or electrical connection. Furthermore, an "electrical connection" may mean the presence of other elements between two elements.

[0067] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same element references are used in the drawings and description to denote the same or similar parts.

[0068] The terms "first," "second," etc., used in this specification or claims are used only to name discreet elements or to distinguish different embodiments or scopes, and are not intended to limit the upper or lower limit of the number of elements, nor to limit the manufacturing or installation order of the elements.

[0069] Figure 1A This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Figure 1B yes Figure 1A A schematic cross-sectional view of the electrophoretic display device according to the embodiment along section line I-I'. For ease of explanation, Figure 1A Some components in the electrophoretic display device 10A (such as the electrophoretic display film 130 and the insulating layer 140) have been omitted. Please also refer to... Figure 1A as well as Figure 1B The electrophoretic display device 10A includes a substrate 100, a color filter array 110, a pixel structure 120, an electrophoretic display film 130, and an insulating layer 140. The color filter array 110 and the pixel structure 120 overlap, and the electrophoretic display film 130 is disposed between the color filter array 110 and the pixel structure 120.

[0070] The substrate 100 is, for example, an active element array substrate, such as a thin film transistor (TFT) array substrate or a thin film diode (TFD) array substrate, and includes corresponding data lines and scan lines for driving the pixel structure 120.

[0071] The color filter array 110 includes a red filter unit 110R, a green filter unit 110G, a blue filter unit 110B, a filter substrate 111, an adhesive layer 112, and a cover plate 113. The red filter unit 110R, green filter unit 110G, and blue filter unit 110B are arranged alternately in an array along a first direction X and a second direction Y, respectively, and each includes corresponding red, green, and blue filter materials, so that reflected ambient light passing through the filter units can provide corresponding red, green, and blue light. The filter substrate 111 may include opposing electrodes (e.g., a common electrode, not shown) to provide the necessary electric field to drive the display medium (described later) in the electrophoretic display film 130. The adhesive layer 112 may be an optically transparent adhesive to bond the cover plate 113 to the filter substrate 111. In other embodiments, the color filter array 110 may also include a touch electrode layer (not shown) to enable the electrophoretic display device 10A to have touch sensing functionality; however, the present invention is not limited thereto. Furthermore, in the various figures herein, color filter units of the same color are drawn using the same pattern, omitting duplicate labels. For example, the diagonal lines in each icon represent red filter units 110R, the dotted patterns represent green filter units 110G, and the mixed dotted and triangular patterns represent blue filter units 110B. Further details will not be elaborated upon below.

[0072] It is worth mentioning that, in this embodiment, on the projection surface of the electrophoretic display device 10A in the third direction Z, the areas CR of the red filter unit 110R, CG of the green filter unit 110G, and CB of the blue filter unit 110B are substantially the same. On the other hand, in the following description, the third direction Z can represent the display direction of the electrophoretic display device 10A, and the area of ​​the elements refers to their projected area on the electrophoretic display device 10A in the third direction Z, which will not be elaborated further here. In other words, Figure 1A This can also be viewed as a top view of the display area of ​​the electrophoretic display device 10A. Furthermore, in this embodiment, the first direction X, the second direction Y, and the third direction Z can be substantially perpendicular to each other; however, the invention is not limited thereto. In other embodiments, the first direction X, the second direction Y, and the third direction Z can have other angles.

[0073] The pixel structure 120 includes multiple red pixel electrodes PR, green pixel electrodes PG, and blue pixel electrodes PB, each of which is driven by a driving voltage to drive the electrophoretic display material layer in the electrophoretic display film 130. Specifically, each red pixel electrode PR can be defined by two red subpixels 121R, each green pixel electrode PG can be defined by two green subpixels 121G, and each blue pixel electrode PB can be defined by one blue subpixel 121B. Therefore, from another perspective, the area of ​​a red pixel electrode PR can be defined as the sum of the areas RR of two red subpixels 121R; the area of ​​a green pixel electrode PG can be defined as the sum of the areas RG of two green subpixels 121G; and the area of ​​a blue pixel electrode PB can be defined as the area RB of one blue subpixel 121B. Therefore, in this embodiment, both the green pixel electrode PG and the red pixel electrode PR can extend in the first direction X, meaning that both the green pixel electrode PG and the red pixel electrode PR can have a relatively long length in the first direction X (e.g., Figure 1A (As shown).

[0074] An insulating layer 140 is disposed between the pixel structure 120 and the electrophoretic display film 130. Incidentally, the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB can be separated from each other by the insulating layer 140, achieving electrically independent control of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB. For ease of explanation, the drawing of the insulating layer 140 between each pair of red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB is omitted in the figures.

[0075] An electrophoretic display film 130 is disposed on the pixel structure 120. In this embodiment, the electrophoretic display film 130 is an electrophoretic display material layer, which may include, for example, a microcapsule structure or a microcup structure; the invention is not limited thereto. In this embodiment, the electrophoretic display film 130 is illustrated by way of a microcapsule structure. For example, the electrophoretic display film 130 may include multiple microcapsule structures 131, each microcapsule structure 131 including an electrophoretic solution 132, multiple black charged particles B, and multiple white charged particles W. An electric field is generated by a common voltage provided by a common electrode disposed opposite to each other in the third direction Z and a driving voltage provided by a pixel electrode, causing the multiple black charged particles B or multiple white charged particles W to move to the top of the microcapsule structure 131, thereby allowing the electrophoretic display film 130 to absorb or reflect ambient light. When the reflected ambient light passes through the red filter unit 110R, green filter unit 110G, and blue filter unit 110B of the color filter array 110, it can provide red image light, green image light, or blue image light. Of course, the present invention is not limited thereto. In other embodiments not shown, each microcapsule structure 131 of the electrophoretic display film 130 may also include charged particles of other colors.

[0076] The electrophoretic display device 10A may also have a front light module provided above the color filter array 110 according to actual needs. The front light module may include, for example, solid transparent optical adhesive, light guide plate, protective glass, etc. (not shown). Those skilled in the art can combine the above components with the electrophoretic display device 10A, but the present invention is not limited thereto.

[0077] It is worth mentioning that, compared to conventional pixel structures where all pixel electrodes have the same area (for example, the red pixel electrode is a red subpixel 121R, the green pixel electrode is a green subpixel 121G, and the blue pixel electrode is a blue subpixel 121B, all of which are rectangles of the same size), in the pixel structure 120 of the present invention, the area of ​​the blue pixel electrode PB is smaller than the area of ​​the red pixel electrode PR, and the area of ​​the blue pixel electrode PB is smaller than the area of ​​the green pixel electrode PG.

[0078] For example, the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB are arranged closely together, and in this embodiment, the blue pixel electrode PB can extend in the first direction X and the second direction Y respectively, having a first end e1 and a second end e2 that are perpendicular to each other. The extension of the blue pixel electrode PB causes the outline of the adjacent red pixel electrode PR to recede away from the blue pixel electrode PB. Similarly, the outline of the green pixel electrode PG adjacent to the blue pixel electrode PB also recedes away from the blue pixel electrode PB. In other words, compared to the pattern where the red subpixel 121R, green subpixel 121G, and blue subpixel 121B are all squares of the same size, in this embodiment, the blue pixel electrode PB can be cross-shaped, and the first end e1 and the second end e2 of the cross shape extend towards the adjacent green subpixel 121G and the adjacent red subpixel 121R respectively, so that the area RB of a blue subpixel 121B is larger than the area RR of a red subpixel 121R and larger than the area RG of a green subpixel 121G.

[0079] It should be noted that, unless otherwise specified in this article, "adjacent sub-pixels A and B" means that there are no other sub-pixels between sub-pixels A and B. Similarly, "adjacent pixel electrodes A and B" means that there are no other pixel electrodes between pixel electrodes A and B, and this will not be elaborated further.

[0080] For example, if the area RR of a red subpixel 121R is 0.95 units, then the area of ​​a red pixel electrode PR is 0.95 * 2 = 1.9 units. Similarly, if the area RG of a green subpixel 121G is 0.95 units, then the area of ​​a green pixel electrode PG is 0.95 * 2 = 1.9 units. The area RB of a blue subpixel 121B (i.e., one blue pixel electrode PB) is 1 + 0.05 * 4 = 1.2 units. That is, compared to the conventional system where the areas of red, green, and blue pixel electrodes are equal (occupying 33.3%, 33.3%, and 33.3% of a pixel respectively), in this embodiment of the invention, the areas of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB can each occupy 38%, 38%, and 24% of a pixel respectively. Therefore, a higher proportion of the red pixel electrode PR and a higher proportion of the green pixel electrode PG allow the red and green light reflected by the electrophoretic display device 10A to be brighter, and the blue light to be darker, further improving the contrast of the displayed image. Of course, this invention is not limited to this; in other embodiments, the areas of the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB can be in other proportions.

[0081] As mentioned above, since the areas CR of the red filter unit 110R, CG of the green filter unit 110G, and CB of the blue filter unit 110B can all be substantially the same, and when the ratio of the area CB of the blue filter unit 110B to the area RB of the blue pixel electrode PB is at its maximum value (which can also be understood as the pixel coverage of the blue filter unit 110B or the fill factor of the blue pixel), the area CB can be equal to the area RB, that is, both being 1.2 units. In this case, BFF can be 100%. Based on the above, the maximum value of the ratio RFF (which can also be understood as the pixel coverage of the red filter unit 110R or the fill factor of the red pixel) to the area of ​​the red pixel electrode PR is (1.2 / 1.9) = 63%, and the maximum value of the ratio GFF (which can also be understood as the pixel coverage of the green filter unit 110G or the fill factor of the green pixel) to the area of ​​the green pixel electrode PG is (1.2 / 1.9) = 63%. This can also be understood as the electrophoretic display device 10A having RFF ≤ 63%, GFF ≤ 63%, and BFF ≤ 100%. Since BFF is greater than both RFF and GFF, the electrophoretic display device 10A, while possessing high contrast, also easily maintains the white balance of the displayed image, thus improving color shift issues.

[0082] As a comparative example, if the red subpixel 121R, green subpixel 121G, and blue subpixel 121B are all squares of the same size (e.g., each with an area of ​​1 unit), and the blue filter unit 110B (with an area of ​​1 unit) corresponds to 1 blue subpixel 121B, the red filter unit 110R (with an area of ​​1 unit) corresponds to 2 red subpixels 121R, and the green filter unit 110G (with an area of ​​1 unit) corresponds to 2 green subpixels 121G, then the maximum RFF of such an electrophoretic display device is (1 / 2) = 50%; the maximum GFF is (1 / 2) = 50%; and the maximum BFF is (1 / 1) = 100%. Higher pixel coverage represents higher brightness. In other words, the electrophoretic display device 10A of this embodiment, while maintaining white balance, can further brighten the reflected red and green light, thereby further improving the brightness of the displayed image.

[0083] It must be noted that the following embodiments use the component reference numerals and some content from the foregoing embodiments, with the same reference numerals used to represent the same or similar components, and descriptions of the same technical content omitted. For explanations of the omitted parts, please refer to the foregoing embodiments; these will not be repeated in the following embodiments.

[0084] Figure 2This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 2 The electrophoretic display device 10B is similar to the aforementioned electrophoretic display device 10A, with the main difference being the shape of the pixel electrodes. In the electrophoretic display device 10B, the outline of the blue pixel electrode PB (or blue sub-pixel 121B) can be rectangular or square. Therefore, the outline of the green pixel electrode PG adjacent to the blue pixel electrode PB recedes away from the blue pixel electrode PB; for example, the outline of the adjacent green sub-pixel 121G becomes a rectangle with a missing corner. Similarly, the outline of the red pixel electrode PR adjacent to the blue pixel electrode PB recedes away from the blue pixel electrode PB; for example, the outline of the adjacent red sub-pixel 121R also becomes a rectangle with a missing corner.

[0085] Figure 3 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 3 The electrophoretic display device 10C is similar to the aforementioned electrophoretic display device 10A, with the main difference being the different shapes of the pixel electrodes and color filter units. In the electrophoretic display device 10C, the outline of the blue pixel electrode PB (or blue sub-pixel 121B) can be the same as that of the blue filter unit 110B, both being circular, and the BFF is essentially 100%. Therefore, the outline of the green pixel electrode PG adjacent to the blue pixel electrode PB recedes away from the blue pixel electrode PB; for example, the adjacent green sub-pixel 121G has an arc-shaped outline. Similarly, the outline of the red pixel electrode PR adjacent to the blue pixel electrode PB recedes away from the blue pixel electrode PB; for example, the adjacent red sub-pixel 121R has an arc-shaped outline.

[0086] On the other hand, in this embodiment, the shape of the red filter unit 110R is the same as the shape of the red pixel electrode PR (e.g., both are rectangles with two arc-shaped notches), the shape of the green filter unit 110G is the same as the shape of the green pixel electrode PG (e.g., both are rectangles with two arc-shaped notches), and the shape of the blue filter unit 110B is the same as the shape of the blue pixel electrode PB (e.g., both are circles). This further improves the space utilization of the red filter unit 110R, the green filter unit 110G, and the blue filter unit 110B.

[0087] Figure 4 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 4The electrophoretic display device 10D is similar to the aforementioned electrophoretic display device 10C, with the main difference being that the extension directions of the green pixel electrode PG and the red pixel electrode PR are different, and the extension directions of the green filter unit 110G and the red filter unit 110R are also different. Specifically, in the electrophoretic display device 10D, both green sub-pixels 121G can be arranged in the first direction X, resulting in the green pixel electrode PG and the green filter unit 110G having relatively long lengths in the first direction X. Conversely, both red sub-pixels 121R can be arranged in the second direction Y, resulting in the red pixel electrode PR and the red filter unit 110R having relatively long lengths in the second direction Y. That is, the extension directions of the green pixel electrode PG and the red pixel electrode PR can be perpendicular to each other.

[0088] Figure 5 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 5 The electrophoretic display device 10E is similar to the aforementioned electrophoretic display device 10A, with the main difference being the different extending direction of the blue pixel electrode PB. Specifically, in the electrophoretic display device 10E, the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB all have the same width in the second direction Y. Furthermore, the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB all extend in the first direction X, meaning they have a relatively long length in the first direction X. In other words, the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB can all be rectangular. In addition, in this embodiment, the shape of the red filter unit 110R is the same as the shape of the red pixel electrode PR, the shape of the green filter unit 110G is the same as the shape of the green pixel electrode PG, and the shape of the blue filter unit 110B is the same as the shape of the blue pixel electrode PB (e.g., both are rectangular).

[0089] Furthermore, the blue subpixel 121B can extend in the same direction as and in the opposite direction of the first direction X, respectively, making the area of ​​the blue pixel electrode PB larger (e.g., 1.2 units), causing the adjacent red subpixel 121R' and the adjacent green subpixel 121G' to shrink (e.g., both to 0.9 units). The area of ​​the red pixel electrode PR is formed by the sum of the red subpixel 121R and another red subpixel 121R', for example, 1 + 0.9 = 1.9 (units). Similarly, the area of ​​the green pixel electrode PG is formed by the sum of the green subpixel 121G and another green subpixel 121G', for example, also 1 + 0.9 = 1.9 (units). A similar effect to the aforementioned electrophoretic display device 10A can be achieved, which will not be elaborated here.

[0090] Furthermore, since the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB can all be rectangular, this embodiment can have smooth edges in one direction (e.g., in the first direction X), which reduces the difficulty of manufacturing the pixel structure 120 and the color filter array 110.

[0091] Figure 6 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 6 The electrophoretic display device 10F is similar to the aforementioned electrophoretic display device 10A, with the main difference being the different extension direction of the blue pixel electrode PB. Specifically, in the electrophoretic display device 10F, the blue pixel electrode PB (or blue sub-pixel 121B) extends towards the red pixel electrode PR in the first direction X and towards the red pixel electrode PR in the second direction Y, but not towards the green pixel electrode PG. This results in the area of ​​the green pixel electrode PG being larger than the area of ​​the red pixel electrode PR. Alternatively, the blue pixel electrode PB causes the outlines of its adjacent red pixel electrode PR and another red pixel electrode PR to recede away from the blue pixel electrode PB.

[0092] For example, in Figure 6 The blue pixel electrode PB (or blue sub-pixel 121B) can extend in the second direction Y and the first direction X, such that its area is, for example, 1.2 units. The two red sub-pixels 121R' located to the right and below the blue pixel electrode PB can each have an area of ​​0.9 units. The green sub-pixels 121G can each have an area of ​​1 unit. Therefore, in this embodiment of the invention, the areas of the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB can be 0.9*2 = 1.8 units, 1*2 = 2 units, and 1*1.2 = 1.2 units, respectively. This can also be understood as the areas of the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB accounting for 36%, 40%, and 24% of a pixel, respectively. Because the green pixel electrode PG has a larger area, it can provide brighter green light and higher contrast.

[0093] As mentioned above, since the areas of the red filter unit 110R, the green filter unit 110G, and the blue filter unit 110B are essentially the same, the electrophoretic display device 10F of this embodiment can further satisfy the following conditions: RFF ≤ 67%; GFF ≤ 60%; and BFF ≤ 100%. The relevant calculations or principles can be referred to in the preceding paragraphs and will not be repeated here.

[0094] Figure 7This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 7 The electrophoretic display device 10G is similar to the aforementioned electrophoretic display device 10F, with the main difference being the different extension direction of the blue pixel electrode PB. Specifically, in the electrophoretic display device 10G, the blue pixel electrode PB (or blue sub-pixel 121B) extends only towards the red pixel electrode PR in the first direction X, and not towards the other red pixel electrode PR in the second direction Y, nor towards the green pixel electrode PG in the first direction X, making the area of ​​the green pixel electrode PG larger than the area of ​​the red pixel electrode PR. In other words, the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB all extend in the first direction X, meaning they have a relatively long length in the first direction X; therefore, the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB can all be rectangular.

[0095] For example, in Figure 7 The blue pixel electrode PB (or blue sub-pixel 121B) can extend in the opposite direction of the first direction X, such that its area is, for example, 1.2 units. The area of ​​the red sub-pixel 121R' located above the blue pixel electrode PB can be 0.8 units, and the area of ​​the green sub-pixel 121G can both be 1 unit. Therefore, in this embodiment of the invention, the areas of the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB can also be 0.8 + 1 = 1.8 units, 1 * 2 = 2 units, and 1 * 1.2 = 1.2 units, respectively. This can also be understood as the areas of the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB accounting for 36%, 40%, and 24% of a pixel, respectively. Because the green pixel electrode PG has a larger area, it can provide brighter green light and higher contrast.

[0096] As mentioned above, since the areas of the red filter unit 110R, the green filter unit 110G, and the blue filter unit 110B are essentially the same, the electrophoretic display device 10G of this embodiment can also satisfy the following conditions: RFF ≤ 67%; GFF ≤ 60%; and BFF ≤ 100%. The relevant calculations or principles can be found in the preceding paragraphs and will not be repeated here.

[0097] Figure 8 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 8The electrophoretic display device 10H is similar to the aforementioned electrophoretic display device 10G, with the main difference being that the red pixel electrode PR and the green pixel electrode PG extend in different directions, and the blue pixel electrode PB extends in different directions as well. Specifically, in the electrophoretic display device 10H, the blue pixel electrode PB (or blue sub-pixel 121B) extends towards the red pixel electrode PR in the same and opposite directions of the first direction X, but does not extend towards the green pixel electrode PG in the second direction Y, making the area of ​​the green pixel electrode PG larger than the area of ​​the red pixel electrode PR. In other words, the two green sub-pixels 121G of a single green pixel electrode PG are both arranged in the first direction X, therefore both the blue pixel electrode PB and the green pixel electrode PG have relatively long lengths in the first direction X, making both the green pixel electrode PG and the blue pixel electrode PB rectangular. Conversely, the two red sub-pixels 121R' of a single red pixel electrode PR are both arranged in the second direction Y, therefore the outline of the red pixel electrode PR (and the corresponding red filter unit 110R) can extend and bend in the second direction Y.

[0098] Similarly, the area of ​​the blue pixel electrode PB (or blue sub-pixel 121B) of the electrophoretic display device 10H is, for example, 1.2 units. The areas of the two red sub-pixels 121R' located above the blue pixel electrode PB can each be 0.9 units. The area of ​​the green sub-pixel 121G can each be 1 unit. Therefore, the proportions of the area of ​​the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB to a pixel can be 36%, 40%, and 24%, respectively; the electrophoretic display device 10H can also satisfy the following conditions: RFF ≤ 67%; GFF ≤ 60%; and BFF ≤ 100%. The relevant calculations or principles can be found in the preceding paragraphs and will not be repeated here.

[0099] Figure 9 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 9The electrophoretic display device 10I is similar to the aforementioned electrophoretic display device 10H, with the main difference being the different extension direction of the blue pixel electrode PB. Specifically, in the electrophoretic display device 10I, the blue pixel electrode PB (or blue sub-pixel 121B) extends only towards the red pixel electrode PR in the opposite direction of the first direction X, and not towards the red pixel electrode PR in the positive direction of the first direction X, nor towards the green pixel electrode PG in the second direction Y. This causes the outline of the red pixel electrode PR adjacent to the blue pixel electrode PB to recede away from the blue pixel electrode PB (for example, the outline of the red pixel electrode PR recedes in the opposite direction of the first direction X). As a result, the area of ​​the green pixel electrode PG is larger than the area of ​​the red pixel electrode PR. In other words, the outline of the red pixel electrode PR can be considered as a rectangle with a missing corner.

[0100] For example, in Figure 9 The blue pixel electrode PB (or blue sub-pixel 121B) can extend in the opposite direction of the first direction X, such that its area is, for example, 1.2 units. The area of ​​the red sub-pixel 121R' located above the blue pixel electrode PB can be 0.8 units. The area of ​​the green sub-pixel 121G can both be 1 unit. Therefore, in this embodiment of the invention, the areas of the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB can also be 0.8 + 1 = 1.8 units, 1 * 2 = 2 units, and 1 * 1.2 = 1.2 units, respectively. It can also be understood that the areas of the red pixel electrode PR, the green pixel electrode PG, and the blue pixel electrode PB account for 36%, 40%, and 24% of a pixel, respectively. Because the green pixel electrode PG has a larger area proportion, it can provide brighter green light and higher contrast.

[0101] As mentioned above, since the areas of the red filter unit 110R, the green filter unit 110G, and the blue filter unit 110B are essentially the same, the electrophoretic display device 10H of this embodiment can also satisfy the following conditions: RFF ≤ 67%; GFF ≤ 60%; and BFF ≤ 100%. The relevant calculations or principles can be found in the preceding paragraphs and will not be repeated here.

[0102] Figure 10 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 10The electrophoretic display device 10J is similar to the aforementioned electrophoretic display device 10A, with the main differences being: the arrangement directions of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB are different, as are the arrangement directions of the red filter unit 110R, green filter unit 110G, and blue filter unit 110B. Specifically, the electrophoretic display device 10J may include multiple pixel units 121, and each pixel unit 121 includes a red filter unit 110R, a green filter unit 110G, and a blue filter unit 110B; and corresponding red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB. Furthermore, in the color filter array 110 (… Figure 10 In each pixel unit 121 (not shown), the red filter unit 110R, green filter unit 110G, and blue filter unit 110B are arranged in the same way (e.g., from left to right, they are all red filter unit 110R, green filter unit 110G, and blue filter unit 110B) and have the same shape (e.g., rectangular). Similarly, the red pixel electrodes PR of each pixel unit 121 can all be aligned in the same direction, the green pixel electrodes PG of each pixel unit 121 can all be aligned in the same direction, and the blue pixel electrodes PB of each pixel unit 121 can all be aligned in the same direction.

[0103] In detail, in this embodiment, the area of ​​a red pixel electrode PR can be defined by a red subpixel 121R, the area of ​​a green pixel electrode PG can be defined by a green subpixel 121G', and the area of ​​a blue pixel electrode PB can be defined by a blue subpixel 121B. It is worth noting that in this embodiment, the area of ​​the red subpixel 121R can be smaller than the area of ​​the green pixel electrode PG (or green subpixel 121G') and larger than the area of ​​the blue pixel electrode PB (or blue subpixel 121B), for example, the red subpixel 121R can all be 1 unit. The area of ​​the green subpixel 121G' can increase by extending towards the blue subpixel 121B, for example... Figure 10The green subpixel 121G (represented by a dashed line) becomes the green subpixel 121G' (represented by a solid line), and the area of ​​the green subpixel 121G' is, for example, 1.2 units. The area of ​​the blue subpixel 121B located to the right of the green pixel electrode PG can be reduced to 0.8 units by moving away from the green subpixel 121G'. Therefore, the areas of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB in this embodiment of the invention can also be 1 unit, 1.2 units, and 0.8 units, respectively. It can also be understood that the areas of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB account for 33.3%, 40%, and 26.7% of a pixel, respectively. Because the green pixel electrode PG has a larger area ratio, it can provide brighter green light and higher contrast. Furthermore, the architecture of the color filter unit 110 and the pixel structure 120 is simple, easy to design, reduces product costs, and is suitable for improving yield.

[0104] As mentioned above, since the areas of the red filter unit 110R, the green filter unit 110G, and the blue filter unit 110B are essentially the same, the electrophoretic display device 10J of this embodiment can also satisfy the following conditions: RFF ≤ 75%; GFF ≤ 62.5%; and BFF ≤ 93.7%. The relevant calculations or principles can be referred to in the preceding paragraphs and will not be repeated here.

[0105] Figure 11 This is a top view schematic diagram of the pixel structure and color filter array of an electrophoretic display device according to an embodiment of the present invention. Please refer to... Figure 11 The electrophoretic display device 10K is similar to the aforementioned electrophoretic display device 10J, with the main differences being: the arrangement directions of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB are different, as are the arrangement directions of the red filter unit 110R, green filter unit 110G, and blue filter unit 110B. Specifically, in the electrophoretic display device 10K, every two adjacent pixels are of a different color. For example, the pixel electrode adjacent to the red pixel electrode PR is either a blue pixel electrode PB or a green pixel electrode PG. The arrangement of pixel electrodes for other colors can also be described as described above.

[0106] On the other hand, the area of ​​the green subpixel 121G' can be increased by extending it in the direction of the blue subpixel 121B. In detail, Figure 11The area of ​​a red pixel electrode PR can be defined by a red subpixel 121R, the area of ​​a green pixel electrode PG can be defined by a green subpixel 121G', and the area of ​​a blue pixel electrode PB can be defined by a blue subpixel 121B. The range of the green subpixel 121G' can extend from boundary BD1 to boundary BD2, and its area is, for example, 1.2 units. The range of the blue subpixel 121B, located to the right of the green pixel electrode PG, recedes from boundary BD1 to boundary BD2, making its area 0.8 units. The area of ​​the red subpixel 121R is 1 unit. Therefore, in this embodiment of the invention, the areas of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB can also be 1 unit, 1.2 units, and 0.8 units, respectively. It can also be understood that the areas of the red pixel electrode PR, green pixel electrode PG, and blue pixel electrode PB account for 33.3%, 40%, and 26.7% of a pixel, respectively. Because the green pixel electrode PG has a larger area, it can provide brighter green light. Furthermore, the color filter unit 110 and pixel structure 120 have a simple architecture, are easy to design, can reduce product costs, and are suitable for improving yield.

[0107] Similar to the aforementioned, since the areas of the red filter unit 110R, the green filter unit 110G, and the blue filter unit 110B are substantially the same, the electrophoretic display device 10K of this embodiment can also satisfy the following conditions: RFF ≤ 75%; GFF ≤ 62.5%; and BFF ≤ 93.7%. Of course, this disclosure is not limited to this. In other embodiments not shown, the areas of the green subpixel 121G' and the red subpixel 121R can both be increased by extending towards the blue subpixel 121B. This results in a larger area for the green subpixel 121G' and the red subpixel 121R (e.g., both 1.1 units), while the area for the blue subpixel 121B is smaller (e.g., 0.8 units).

[0108] In summary, in the embodiments of the present invention, since the areas of the green and red pixel electrodes are both larger than the area of ​​the blue pixel electrode, the green and yellow light displayed by the electrophoretic display device can be brighter, while the blue light can be darker, effectively improving the contrast and saturation of the displayed image. On the other hand, since the areas of the red, green, and blue filter units are all the same, the pixel coverage ratio (BFF) of the blue filter unit is greater than that of the green filter unit (GFF) and the red filter unit (RFF). Therefore, while adjusting the brightness of the primary color light, it is also beneficial to maintain the white balance of the electrophoretic display device, reducing color shift issues and effectively improving the contrast and image quality of the electrophoretic display device.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrophoretic display device, comprising: a pixel structure including a red pixel electrode, a green pixel electrode, and a blue pixel electrode, wherein an area of the blue pixel electrode is smaller than an area of the red pixel electrode, and an area of the blue pixel electrode is smaller than an area of the green pixel electrode; and a color filter array overlapping the pixel structure, the color filter array including: a red filter unit overlapping the red pixel electrode, a ratio of an area of the red filter unit to the area of the red pixel electrode being RFF; a green filter unit overlapping the green pixel electrode, a ratio of an area of the green filter unit to the area of the green pixel electrode being GFF; and a blue filter unit overlapping the blue pixel electrode, a ratio of an area of the blue filter unit to the area of the blue pixel electrode being BFF, wherein the ratios of the areas satisfy the following condition: BFF > RFF > GFF. Further satisfying the following condition: RFF < 75%; GFF < 62.5%; and BFF < 93.7%.

2. The electrophoretic display device according to claim 1, wherein Further satisfying the following condition: RFF < 63%; GFF < 63%; and BFF < 100%.

3. The electrophoretic display apparatus of claim 1, wherein, Further satisfying the following condition: RFF < 67%; GFF < 60%; and BFF < 100%.

4. The electrophoretic display apparatus of claim 1, wherein, having a first direction and a second direction perpendicular to each other on a display surface of the electrophoretic display device, the blue pixel electrode extending in the first direction and extending in the second direction, respectively, such that a profile of the red pixel electrode adjacent to the blue pixel electrode and a profile of the green pixel electrode adjacent to the blue pixel electrode both recede away from the blue pixel electrode.

5. The electrophoretic display apparatus of claim 1, wherein, the profile of the blue pixel electrode being a cross shape, the cross shape extending in the first direction and extending in the second direction at two ends of the cross shape perpendicular to each other.

6. An electrophoretic display device according to claim 5, wherein having a first direction and a second direction perpendicular to each other on a display surface of the electrophoretic display device, the red pixel electrode, the green pixel electrode, and the blue pixel electrode all having a same width in the second direction, and the red pixel electrode, the green pixel electrode, and the blue pixel electrode all extending in the first direction.

7. The electrophoretic display apparatus of claim 1, wherein, the profile of the blue pixel electrode being substantially circular, such that a profile of the red pixel electrode adjacent to the blue pixel electrode and a profile of the green pixel electrode adjacent to the blue pixel electrode both recede away from the blue pixel electrode.

8. The electrophoretic display apparatus of claim 1, wherein, further including another red pixel electrode, wherein having a first direction and a second direction perpendicular to each other on a display surface of the electrophoretic display device, the red pixel electrode and the another red pixel electrode are located in the first direction and in the second direction of the blue pixel electrode, respectively, the blue pixel electrode extending toward the red pixel electrode and extending toward the another red pixel electrode, such that a profile of the red pixel electrode adjacent to the blue pixel electrode and a profile of the another red pixel electrode both recede away from the blue pixel electrode.

9. The electrophoretic display apparatus of claim 1, wherein, ​ 10. The electrophoretic display apparatus of claim 1, wherein, The blue pixel electrode extends towards the red pixel electrode, causing the profile of the red pixel electrode adjacent to the blue pixel electrode to recede in a direction away from the blue pixel electrode.

11. The electrophoretic display apparatus of claim 1, wherein, The shape of the red filter unit is the same as the shape of the red pixel electrode, the shape of the green filter unit is the same as the shape of the green pixel electrode, and the shape of the blue filter unit is the same as the shape of the blue pixel electrode.

12. The electrophoretic display apparatus of claim 1, wherein, The green pixel electrode extends towards the blue pixel electrode, causing the profile of the blue pixel electrode adjacent to the green pixel electrode to recede in a direction away from the green pixel electrode.

13. The electrophoretic display apparatus of claim 1, wherein, Also included are: An electrophoretic display film disposed between the pixel structure and the color filter array, the electrophoretic display film comprising a microcapsule electrophoretic structure or a microcup electrophoretic structure.

14. The electrophoretic display apparatus of claim 1, wherein, The area of the red filter unit, the area of the green filter unit, and the area of the blue filter unit are substantially the same.

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