Display device

Abstract

A display device includes a plurality of pixels, each pixel having a display area and a non-display area, and each pixel includes an upper transmissive display layer, a middle transmissive display layer, and a lower reflective display layer stacked in order from top to bottom. The upper transmissive display layer, the middle transmissive display layer, and the lower reflective display layer respectively include: a first electrode located in the display area; a second electrode located in the non-display area; an electrophoretic medium located on one side of the first electrode and the second electrode; and charged particles suspended in the electrophoretic medium. The colors of the charged particles in the upper transmissive display layer, the middle transmissive display layer, and the lower reflective display layer are different from each other.

Description

Technical Field

[0001] The present invention relates to a display device, and in particular to an electrophoretic display device. Background Art

[0002] Electrophoretic displays have attracted market attention for their energy-saving and environmentally friendly advantages. They use the reflection or absorption of ambient light to produce bright or dark states to achieve the purpose of display, so there is no need to set up additional light sources. Generally speaking, the electrophoretic display film (EPD film) of an electrophoretic display is mainly composed of an electrophoretic fluid and charged particles suspended in the electrophoretic fluid. It drives the charged particles to move by applying voltage to switch the dark state and bright state of each sub-pixel.

[0003] However, when an electrophoretic display combines red, green and blue color filter structures to achieve full color with a "superimposed" primary color system, the reflectivity of the superimposed sub-pixels of each color is reduced by at least two-thirds, resulting in a significant reduction in contrast. Summary of the invention

[0004] An object of the present invention is to provide a display device with improved reflectivity and contrast.

[0005] An embodiment of the present invention provides a display device, comprising: a plurality of pixels, each pixel having a display area and a non-display area, and each pixel comprising an upper transmissive display layer, a middle transmissive display layer and a lower reflective display layer stacked in sequence from top to bottom, wherein the upper transmissive display layer, the middle transmissive display layer and the lower reflective display layer respectively comprise: a first electrode located in the display area; a second electrode located in the non-display area; an electrophoretic medium located on one side of the first electrode and the second electrode; and charged particles suspended in the electrophoretic medium, wherein the colors of the charged particles in the upper transmissive display layer, the middle transmissive display layer and the lower reflective display layer are different from each other.

[0006] In an embodiment of the present invention, each of the display layers further includes a bottom plate, and the first electrode and the second electrode of each display layer are located between the bottom plate and the electrophoretic medium of each display layer.

[0007] In one embodiment of the present invention, the first electrode of the bottom reflective display layer is a reflective electrode.

[0008] In one embodiment of the present invention, the bottom reflective display layer further includes a reflective structure located between the first electrode and the bottom plate.

[0009] In one embodiment of the present invention, the first electrode of the bottom reflective display layer is a transparent electrode.

[0010] In one embodiment of the present invention, the above-mentioned reflective structure includes a surface microstructure.

[0011] In an embodiment of the present invention, each of the above-mentioned display layers further includes a bottom plate, and the first electrode of the lower reflective display layer is located between the electrophoretic medium of the lower reflective display layer and the bottom plate of the middle transmissive display layer.

[0012] In one embodiment of the present invention, the bottom reflective display layer further includes a reflective structure located in the display area and between the bottom plate and the electrophoretic medium.

[0013] In one embodiment of the present invention, the above-mentioned reflective structure includes a surface microstructure.

[0014] In one embodiment of the present invention, the lower reflective display layer further includes a total reflection structure located between the first electrode and the bottom plate of the middle transmissive display layer.

[0015] In one embodiment of the present invention, the refractive index of the total reflection structure is greater than the refractive index of the electrophoretic medium of the bottom reflection display layer.

[0016] In one embodiment of the present invention, the upper transmissive display layer further includes an upper light-transmissive cover plate, and in the upper transmissive display layer, the electrophoretic medium is located between the upper light-transmissive cover plate and the bottom plate.

[0017] In one embodiment of the present invention, the aforementioned middle transmissive display layer further includes a first light-transmissive cover plate, and in the middle transmissive display layer, the electrophoretic medium is located between the first light-transmissive cover plate and the bottom plate.

[0018] In one embodiment of the present invention, the aforementioned bottom reflective display layer further includes a second light-transmitting cover plate, and in the bottom reflective display layer, the electrophoretic medium is located between the second light-transmitting cover plate and the bottom plate.

[0019] In an embodiment of the present invention, each of the display layers further includes a light shielding pattern located on the second electrode.

[0020] In one embodiment of the present invention, the total area of ​​the second electrodes of the upper transmissive display layer, the middle transmissive display layer or the lower reflective display layer is 5% to 45% of the total area of ​​the display device.

[0021] In an embodiment of the present invention, the display device further includes a dielectric layer located between the first electrode, the second electrode and the electrophoretic medium.

[0022] Based on the above, the display device of the present invention realizes full-color display according to the subtractive color mixing principle by stacking display layers containing charged particles of different colors, which can improve the reflectivity and thus improve the contrast of the display device.

[0023] 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1A is a cross-sectional schematic diagram of a display device according to an embodiment of the present invention.

[0025] Figures 1B to 1F yes Figure 1A Schematic cross-sectional view of a display device in various operating states.

[0026] Figure 2 is a cross-sectional schematic diagram of a display device according to an embodiment of the present invention.

[0027] Figure 3 is a cross-sectional schematic diagram of a display device according to an embodiment of the present invention.

[0028] Figure 4 is a cross-sectional schematic diagram of a display device according to an embodiment of the present invention.

[0029] Figure 5A is a cross-sectional schematic diagram of a display device according to an embodiment of the present invention.

[0030] Figure 5B yes Figure 5A A cross-sectional schematic diagram of a lower reflective display layer of a display device showing that charged particles are adsorbed on electrodes.

[0031] Figure 5C yes Figure 5A A cross-sectional schematic diagram of a lower reflective display layer of a display device showing that charged particles are adsorbed on electrodes.

[0032] The reference numerals are as follows:

[0033] 10, 20, 30, 40, 50: Display device

[0034] AL, IR1, IR2, IR3, IR4, IR5: Ambient light

[0035] BB, MB, UB: Shading pattern

[0036] BC, MC: Translucent cover

[0037] BI, MI, UI: Dielectric layer

[0038] BI31, BI32, BI41, BI42, BI51, BI52: Dielectric layer

[0039] BL, BL2, BL3, BL4, BL5: bottom reflective display layer

[0040] BM, MM, UM: electrophoresis media

[0041] BP, MP, UP: Charged particles

[0042] BDE, BTE, MDE, MTE, UDE, UTE: Electrodes

[0043] BS, MS, US: Base plate

[0044] BTE2, BTE3, BTE4, BTE5: Electrodes

[0045] DA: Non-display area

[0046] ML: Medium Transmissive Display Layer

[0047] OR1: Total reflection light

[0048] OR3: Reflected light

[0049] OR4: Reflected light

[0050] PX, PX2, PX3, PX4, PX5: Pixel

[0051] R2, R3, R4, R5: Reflective structure

[0052] RL1: Red light

[0053] RL2: Green Light

[0054] RL3: Blue Light

[0055] RL4: White light

[0056] TA: Display area

[0057] TR: Total reflection structure

[0058] UC: Upper transparent cover

[0059] UL: Upper Transmissive Display Layer DETAILED DESCRIPTION

[0060] Figure 1A is a cross-sectional schematic diagram of a display device 10 according to an embodiment of the present invention. Figures 1B to 1F yes Figure 1A 10 is a cross-sectional view of a display device 10 in various operating states. Figure 1A, the display device 10 includes a plurality of pixels PX, and the plurality of pixels PX may be arranged in an array to display an image or an image. In the present embodiment, each pixel PX may have a display area TA and a non-display area DA, and the display area TA and the non-display area DA may be arranged side by side, but not limited thereto. In some embodiments, the non-display area DA may be arranged around the display area TA. In addition, there is no special restriction on the area ratio of the display area TA and the non-display area DA. In each pixel PX, the area of ​​the display area TA is preferably larger than the area of ​​the non-display area DA. In some embodiments, the area ratio of the display area TA may be between 50% and 95%, for example, 55%, 80% or 90%, and the area ratio of the non-display area DA may be between 5% and 50%, for example, 10%, 20% or 45%.

[0061] Each pixel PX includes an upper transmissive display layer UL, a middle transmissive display layer ML and a lower reflective display layer BL stacked in sequence from top to bottom, wherein the transmittance of the upper transmissive display layer UL and the middle transmissive display layer ML is not less than 50%, and the light reflectivity of the lower reflective display layer BL is not less than 50%.

[0062] The upper transmissive display layer UL may include: an electrode UTE located in the display area TA; an electrode UDE located in the non-display area DA; an electrophoretic medium UM located on one side of the electrode UTE and the electrode UDE; and charged particles UP suspended in the electrophoretic medium UM. The electrode UTE and the electrode UDE are electrically separated from each other, and the position of the charged particle UP may be adjusted by adjusting the voltage applied to the electrode UTE and / or the electrode UDE, for example, the position of the charged particle UP may be switched between the electrode UTE and the electrode UDE. In some embodiments, the total area of ​​the electrode UDE may be 5% to 45%, for example, 10%, 20% or 30% of the total area of ​​the display device 10.

[0063] In the present embodiment, the upper transmissive display layer UL may further include a base plate US, and the electrode UTE and the electrode UDE of the upper transmissive display layer UL are located between the base plate US and the electrophoretic medium UM. In the present embodiment, the electrode UTE and the electrode UDE may be located on the same side of the electrophoretic medium UM, but is not limited thereto. In some embodiments, the electrode UTE and the electrode UDE may be located on different sides of the electrophoretic medium UM. The material of the base plate US may include a light-transmitting material, such as polyimide or acrylic. In some embodiments, the base plate US may further include an active element array and a signal line, and the above-mentioned active element array and the signal line may be electrically connected to the electrode UTE and the electrode UDE, respectively.

[0064] In some embodiments, the upper transmissive display layer UL may further include a dielectric layer UI, which is located between the electrode UTE and the electrode UDE and the electrophoretic medium UM, and the dielectric layer UI may cover the electrode UTE and the electrode UDE to protect the electrode UTE and the electrode UDE from being corroded or adhered by the electrophoretic medium UM or impurities in the electrophoretic medium UM.

[0065] In this embodiment, the upper transmissive display layer UL may further include an upper light-transmissive cover plate UC, and the electrophoretic medium UM of the upper transmissive display layer UL may be located between the upper light-transmissive cover plate UC and the bottom plate US. In the upper transmissive display layer UL, the electrode UTE, the electrophoretic medium UM, the bottom plate US, the dielectric layer UI and the upper light-transmissive cover plate UC preferably have good light transmittance.

[0066] In the present embodiment, the upper transmissive display layer UL may further include a light shielding pattern UB, which is located in the non-display area DA and above the electrode UDE, so as to prevent the light reflected by the electrode UDE from affecting the display effect of the display device 10, thereby improving the image contrast. In the present embodiment, the light shielding pattern UB and the electrode UDE are located on different sides of the electrophoretic medium UM, but are not limited thereto. In some embodiments, the light shielding pattern UB and the electrode UDE may be located on the same side of the electrophoretic medium UM, for example, the light shielding pattern UB and the electrode UDE may be located between the upper transparent cover plate UC and the electrophoretic medium UM, and the electrode UDE may be located between the light shielding pattern UB and the electrophoretic medium UM.

[0067] The middle transmission display layer ML may include: an electrode MTE, located in the display area TA; an electrode MDE, located in the non-display area DA; an electrophoretic medium MM, located on one side of the electrode MTE and the electrode MDE; and charged particles MP suspended in the electrophoretic medium MM. The electrode MTE and the electrode MDE are electrically separated from each other. By adjusting the voltage applied to the electrode MTE and / or the electrode MDE, the position of the charged particle MP can be adjusted, for example, the position of the charged particle MP is switched between the electrode MTE and the electrode MDE. In some embodiments, the total area of ​​the electrode MDE may be 5% to 45%, for example, 10%, 20% or 30% of the total area of ​​the display device 10.

[0068] In the present embodiment, the middle transmission display layer ML may further include a bottom plate MS, and the electrode MTE and the electrode MDE of the middle transmission display layer ML are located between the bottom plate MS and the electrophoretic medium MM. In the present embodiment, the electrode MTE and the electrode MDE may be located on the same side of the electrophoretic medium MM, but are not limited thereto. In some embodiments, the electrode MTE and the electrode MDE may be located on different sides of the electrophoretic medium MM. The material of the bottom plate MS may include a light-transmitting material, such as polyimide or acrylic. In some embodiments, the bottom plate MS may further include an active element array and a signal line, and the above-mentioned active element array and the signal line may be electrically connected to the electrode MTE and the electrode MDE, respectively.

[0069] In some embodiments, the middle transmission display layer ML may further include a dielectric layer MI, which is located between the electrodes MTE and MDE and the electrophoretic medium MM, and the dielectric layer MI may cover the electrodes MTE and MDE to protect the electrodes MTE and MDE from being corroded or adhered by the electrophoretic medium MM or impurities in the electrophoretic medium MM.

[0070] In some embodiments, the middle transmissive display layer ML may further include a transparent cover plate MC, and the electrophoretic medium MM of the middle transmissive display layer ML may be located between the transparent cover plate MC and the bottom plate MS. In the middle transmissive display layer ML, the electrode MTE, the electrophoretic medium MM, the bottom plate MS, the dielectric layer MI and the transparent cover plate MC preferably have good light transmittance.

[0071] In the present embodiment, the middle transmissive display layer ML may further include a light shielding pattern MB, which is located in the non-display area DA and above the electrode MDE, so as to prevent the light reflected by the electrode MDE from affecting the display effect of the display device 10, thereby improving the image contrast. In the present embodiment, the light shielding pattern MB and the electrode MDE are located on different sides of the electrophoretic medium MM, but are not limited thereto. In some embodiments, the light shielding pattern MB and the electrode MDE may be located on the same side of the electrophoretic medium MM, for example, the light shielding pattern MB and the electrode MDE may be located between the transparent cover plate MC and the electrophoretic medium MM, and the electrode MDE may be located between the light shielding pattern MB and the electrophoretic medium MM.

[0072] The lower reflective display layer BL may include: an electrode BTE, located in the display area TA; an electrode BDE, located in the non-display area DA; an electrophoretic medium BM, located on one side of the electrode BTE and the electrode BDE; and charged particles BP suspended in the electrophoretic medium BM. The electrode BTE and the electrode BDE are electrically separated from each other. By adjusting the voltage applied to the electrode BTE and / or the electrode BDE, the position of the charged particle BP can be adjusted, for example, the position of the charged particle BP is switched between the electrode BTE and the electrode BDE. In some embodiments, the total area of ​​the electrode BDE may be 5% to 45%, for example, 10%, 20% or 30% of the total area of ​​the display device 10.

[0073] In this embodiment, the electrode BTE is a reflective electrode, so the ambient light entering the display device 10 can first penetrate the upper transmissive display layer UL, then penetrate the middle transmissive display layer ML, then penetrate the lower reflective display layer BL, and then be reflected by the reflective electrode BTE to exit the display device 10. The material of the electrode BTE may include silver, aluminum, alloys thereof, or a stack of the above materials and other conductive materials, but is not limited thereto.

[0074] In the present embodiment, the lower reflective display layer BL may further include a base plate BS, and the electrode BTE and the electrode BDE of the lower reflective display layer BL are located between the base plate BS and the electrophoretic medium BM. The material of the base plate BS may include an opaque / reflective material (for example, a chip, ceramic, etc.), or other applicable materials, but is not limited thereto. In the present embodiment, the electrode BTE and the electrode BDE may be located on the same side of the electrophoretic medium BM, but is not limited thereto. In some embodiments, the electrode BTE and the electrode BDE may be located on different sides of the electrophoretic medium BM. In some embodiments, the base plate BS may further include an active element array and a signal line, and the active element array and the signal line may be electrically connected to the electrode BTE and the electrode BDE, respectively.

[0075] In some embodiments, the lower reflective display layer BL may further include a dielectric layer BI, which is located between the electrode BTE and the electrode BDE and the electrophoretic medium BM, and the dielectric layer BI may cover the electrode BTE and the electrode BDE to protect the electrode BTE and the electrode BDE from being corroded or adhered by the electrophoretic medium BM or impurities in the electrophoretic medium BM.

[0076] In some embodiments, the lower reflective display layer BL may further include a transparent cover plate BC, and the electrophoretic medium BM of the lower reflective display layer BL may be located between the transparent cover plate BC and the base plate BS. In the lower reflective display layer BL, the electrophoretic medium BM, the dielectric layer BI and the transparent cover plate BC preferably have good light transmittance.

[0077] In the present embodiment, the lower reflective display layer BL may further include a light shielding pattern BB, which is located in the non-display area DA and above the electrode BDE, so as to prevent the light reflected by the electrode BDE from affecting the display effect of the display device 10, thereby improving the image contrast. In the present embodiment, the light shielding pattern BB and the electrode BDE are located on different sides of the electrophoretic medium BM, but are not limited thereto. In some embodiments, the light shielding pattern BB and the electrode BDE may be located on the same side of the electrophoretic medium BM, for example, the light shielding pattern BB and the electrode BDE may be located between the transparent cover plate BC and the electrophoretic medium BM, and the electrode BDE may be located between the light shielding pattern BB and the electrophoretic medium BM.

[0078] The colors of the charged particles UP, MP, and BP of the upper transmissive display layer UL, the middle transmissive display layer ML, and the lower reflective display layer BL are different from each other. For example, the color of the charged particles UP may be one of yellow, magenta, and cyan, the color of the charged particles MP may be another of yellow, magenta, and cyan, and the color of the charged particles BP may be another of yellow, magenta, and cyan. In this way, the display device 10 can realize full-color display according to the subtractive color mixing principle, and thus can have improved reflectivity and improved contrast.

[0079] For example, in this embodiment, the color of the charged particles UP is yellow, the color of the charged particles MP is magenta, and the color of the charged particles BP is cyan. Figure 1B When a voltage is applied to the electrode UTE of the upper transmissive display layer UL so that the charged particles UP are adsorbed on the electrode UTE, a voltage is applied to the electrode MTE of the middle transmissive display layer ML so that the charged particles MP are adsorbed on the electrode MTE, and a voltage is applied to the electrode BDE of the lower reflective display layer BL so that the charged particles BP are adsorbed on the electrode BDE, the ambient light AL entering the display device 10 first penetrates the yellow charged particles UP, then penetrates the magenta charged particles MP, and is then reflected by the reflective electrode BTE, so that the pixel PX emits red light RL1.

[0080] Please refer to Figure 1CWhen a voltage is applied to the electrode UTE of the upper transmissive display layer UL so that the charged particles UP are adsorbed on the electrode UTE, a voltage is applied to the electrode MDE of the middle transmissive display layer ML so that the charged particles MP are adsorbed on the electrode MDE, and a voltage is applied to the electrode BTE of the lower reflective display layer BL so that the charged particles BP are adsorbed on the electrode BTE, the ambient light AL entering the display device 10 first penetrates the yellow charged particles UP, then penetrates the cyan charged particles BP, and is then reflected by the reflective electrode BTE, so that the pixel PX emits green light RL2.

[0081] Please refer to Figure 1D When a voltage is applied to the electrode UDE of the upper transmissive display layer UL so that the charged particles UP are adsorbed on the electrode UDE, a voltage is applied to the electrode MTE of the middle transmissive display layer ML so that the charged particles MP are adsorbed on the electrode MTE, and a voltage is applied to the electrode BTE of the lower reflective display layer BL so that the charged particles BP are adsorbed on the electrode BTE, the ambient light AL entering the display device 10 first penetrates the magenta charged particles MP, then penetrates the cyan charged particles BP, and is then reflected by the reflective electrode BTE, so that the pixel PX emits blue light RL3.

[0082] Please refer to Figure 1E When a voltage is applied to the electrode UDE of the upper transmissive display layer UL so that the charged particles UP are adsorbed on the electrode UDE, a voltage is applied to the electrode MDE of the middle transmissive display layer ML so that the charged particles MP are adsorbed on the electrode MDE, and a voltage is applied to the electrode BDE of the lower reflective display layer BL so that the charged particles BP are adsorbed on the electrode BDE, the ambient light AL entering the display device 10 will not pass through the yellow charged particles UP, the magenta charged particles MP and the cyan charged particles BP, so the ambient light AL is reflected by the reflective electrode BTE, and the pixel PX emits white light RL4.

[0083] Please refer to Figure 1F When a voltage is applied to the electrode UTE of the upper transmissive display layer UL so that the charged particles UP are adsorbed on the electrode UTE, a voltage is applied to the electrode MTE of the middle transmissive display layer ML so that the charged particles MP are adsorbed on the electrode MTE, and a voltage is applied to the electrode BTE of the lower reflective display layer BL so that the charged particles BP are adsorbed on the electrode BTE, the ambient light AL entering the display device 10 first penetrates the yellow charged particles UP and absorbs the blue light, then penetrates the magenta charged particles MP and absorbs the green light, and then penetrates the cyan charged particles BP and absorbs the red light, so that the pixel PX appears black or gray.

[0084] Figure 2 is a cross-sectional diagram of a display device 20 according to an embodiment of the present invention. Figure 2, each pixel PX2 of the display device 20 includes an upper transmissive display layer UL, a middle transmissive display layer ML, and a lower reflective display layer BL2. Figure 1A Compared with the display device 10 shown, Figure 2 The difference of the display device 20 shown is that the lower reflective display layer BL2 of the display device 20 also includes a reflective structure R2, and the reflective structure R2 is located between the electrode BTE2 and the bottom plate BS, for example, the electrode BTE2 can cover the reflective structure R2. Due to the presence of the reflective structure R2, the electrode BTE2 may not be a reflective electrode, for example, the electrode BTE2 may be a transparent electrode. In this way, the ambient light entering the display device 20 can pass through the electrode BTE2 and then be reflected by the reflective structure R2 to emit light. The material of the electrode BTE2 may include a nitride of a metal material, an oxide of a metal material, a nitride oxide of a metal material or other suitable materials, or a stacked layer of the above conductive materials, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium gallium zinc oxide, or other suitable oxides, or a stacked layer of at least two of the above, but is not limited thereto.

[0085] In addition, in the present embodiment, the reflective structure R2 may include a surface microstructure having a semicircular surface, and the semicircular surface of the reflective structure R2 may scatter the reflected light, so that the display device 20 can provide a non-mirror display effect. In addition, the dielectric layer BI of the lower reflective display layer BL2 may extend onto the electrode BTE2 and the electrode BDE, and cover the electrode BTE2 and the electrode BDE at the same time.

[0086] Figure 3 is a cross-sectional diagram of a display device 30 according to an embodiment of the present invention. Figure 3 , each pixel PX3 of the display device 30 includes an upper transmissive display layer UL, a middle transmissive display layer ML, and a lower reflective display layer BL3. Figure 1A Compared with the display device 10 shown, Figure 3 The difference of the display device 30 shown is that the electrode BTE3 of the lower reflective display layer BL3 of the display device 30 is located between the electrophoretic medium BM of the lower reflective display layer BL3 and the bottom plate MS of the middle transmissive display layer ML, and the electrode BTE3 is a transparent electrode. More specifically, the electrode BTE3 can be located between the transparent cover plate BC and the electrophoretic medium BM, and the dielectric layer BI31 covers the surface of the electrode BTE3 and is located between the electrophoretic medium BM and the electrode BTE3.

[0087] The material of the electrode BTE3 may include a nitride of a metal material, an oxide of a metal material, a nitride oxide of a metal material or other suitable materials, or a stacked layer of the above conductive materials, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium gallium zinc oxide, or other suitable oxides, or a stacked layer of at least two of the above, but is not limited thereto.

[0088] In addition, in the present embodiment, the lower reflective display layer BL3 further includes a reflective structure R3 and a dielectric layer BI32, the reflective structure R3 is located between the display area TA and the bottom plate BS and the electrophoretic medium BM, and the dielectric layer BI32 covers the electrode BDE and the reflective structure R3. In this way, when a voltage is applied to the electrode BTE3 of the lower reflective display layer BL3 so that the charged particles BP are adsorbed on the electrode BTE3, the light entering the lower reflective display layer BL3 can first penetrate the electrode BTE3 and the cyan charged particles BP, and then be reflected by the reflective structure R3 to emit light.

[0089] Figure 4 is a cross-sectional diagram of a display device 40 according to an embodiment of the present invention. Figure 4 , each pixel PX4 of the display device 40 includes an upper transmissive display layer UL, a middle transmissive display layer ML, and a lower reflective display layer BL4. The electrode BTE4 of the lower reflective display layer BL4 is located between the electrophoretic medium BM of the lower reflective display layer BL4 and the bottom plate MS of the middle transmissive display layer ML, the electrode BTE4 is a transparent electrode, and the dielectric layer BI41 covers the surface of the electrode BTE4 and is located between the electrophoretic medium BM and the electrode BTE4. The lower reflective display layer BL4 also includes a reflective structure R4 and a dielectric layer BI42, and the reflective structure R4 is located in the display area TA and between the bottom plate BS and the electrophoretic medium BM.

[0090] With Figure 3 Compared with the display device 30 shown, Figure 4 The difference of the display device 40 shown is that the dielectric layer BI42 of the display device 40 only covers the electrode BDE but not the reflective structure R4, and the reflective structure R4 may include a surface microstructure with a semicircular surface. The semicircular surface of the reflective structure R4 can scatter the reflected light, so that the display device 40 can provide a non-mirror display effect.

[0091] Figure 5A is a cross-sectional schematic diagram of a display device 50 according to an embodiment of the present invention. Figure 5B yes Figure 5A FIG. 5 is a cross-sectional schematic diagram of a lower reflective display layer BL of a display device 50 , showing that the charged particles BP are adsorbed on the electrode BTE5 . Figure 5C yes Figure 5AThe cross-sectional view of the bottom reflective display layer BL of the display device 50 shows that the charged particles BP are adsorbed on the electrode BDE. Figure 5A , each pixel PX5 of the display device 50 includes an upper transmissive display layer UL, a middle transmissive display layer ML and a lower reflective display layer BL5.

[0092] With Figure 4 Compared with the display device 40 shown, Figure 5A The difference of the display device 50 shown is that the lower reflective display layer BL5 of the display device 50 includes a total reflection structure TR, the total reflection structure TR is located between the electrode BTE5 and the bottom plate MS of the middle transmission display layer ML, the electrode BTE5 is located on the surface of the total reflection structure TR and has a surface profile similar to the total reflection structure TR, and the dielectric layer BI51 covers the surface of the electrode BTE5 and is located between the electrophoretic medium BM and the electrode BTE5. In addition, the electrode BDE and the reflective structure R5 are located between the electrophoretic medium BM and the bottom plate BS, and the dielectric layer BI52 can cover the electrode BDE and the reflective structure R5.

[0093] In this embodiment, the refractive index of the total reflection structure TR is greater than the refractive index of the electrophoretic medium BM of the lower reflective display layer BL5. Figure 5B When the charged particles BP are adsorbed on the electrode BDE and away from the electrode BTE5, the ambient light IR1 entering the lower reflective display layer BL5 can be totally reflected on the surface of the total reflection structure TR to generate total reflection light OR1, and the greater the refractive index difference between the total reflection structure TR and the electrophoretic medium BM, the greater the proportion of the total reflection light OR1 to the ambient light IR1. At the same time, the ambient light IR2 entering the lower reflective display layer BL5 can be absorbed by the shading pattern BB, and the ambient light IR3 that is not totally reflected by the total reflection structure TR can further pass through the electrophoretic medium BM, and then be reflected by the reflection structure R5 to generate reflected light OR3. In this way, by setting the total reflection structure TR, the reflectivity of the display device 50 can be further improved.

[0094] On the other hand, please refer to Figure 5C When the charged particles BP are adsorbed on the electrode BTE5 or BI51 on the surface of the electrode BTE5, the charged particles BP can destroy the total reflection at the interface of the total reflection structure TR, so that the ambient light IR4 entering the lower reflective display layer BL5 can pass through the charged particles BP and be absorbed by the color light of the corresponding spectrum, and then pass through the electrophoretic medium BM, and then be reflected by the reflective structure R5 to generate reflected light OR4. Similarly, the ambient light IR5 entering the lower reflective display layer BL5 can be absorbed by the shading pattern BB.

[0095] In summary, the display device of the present invention can adjust the transmitted light spectrum of the display layer by moving and switching charged particles between electrodes, and can achieve full-color display based on the subtractive color mixing principle by stacking display layers containing charged particles of different colors, thereby improving the reflectivity of the display device and thus improving the contrast of the display device.

[0096] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Those skilled in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the appended claims.

Claims

1. A display device, comprising: A plurality of pixels, each pixel having a display area and a non-display area, and each of the pixels comprises an upper transmissive display layer, a middle transmissive display layer and a lower reflective display layer stacked in sequence from top to bottom, wherein the upper transmissive display layer, the middle transmissive display layer and the lower reflective display layer respectively comprise: A first electrode, located in the display area; A second electrode, located in the non-display area; an electrophoretic medium, located on one side of the first electrode and the second electrode; and Charged particles, suspended in the electrophoretic medium, The colors of the charged particles in the upper transmissive display layer, the middle transmissive display layer and the lower reflective display layer are different from each other. 2 . The display device as claimed in claim 1 , wherein each of the display layers further comprises a base plate, and the first electrode and the second electrode of each of the display layers are located between the base plate of each of the display layers and the electrophoretic medium. 3 . The display device according to claim 2 , wherein the first electrode of the lower reflective display layer is a reflective electrode. 4 . The display device as claimed in claim 2 , wherein the lower reflective display layer further comprises a reflective structure located between the first electrode and the bottom plate. The display device according to claim 4 , wherein the first electrode of the lower reflective display layer is a transparent electrode. The display device of claim 4 , wherein the reflective structure comprises a surface microstructure.

7. The display device as claimed in claim 1, wherein each of the display layers further comprises a bottom plate, and the first electrode of the lower reflective display layer is located between the electrophoretic medium of the lower reflective display layer and the bottom plate of the middle transmissive display layer. 8 . The display device according to claim 7 , wherein the first electrode of the lower reflective display layer is a transparent electrode. 9 . The display device as claimed in claim 7 , wherein the lower reflective display layer further comprises a reflective structure located in the display area and between the bottom plate and the electrophoretic medium.

10. The display device of claim 9, wherein the reflective structure comprises a surface microstructure.

11. The display device according to claim 7, wherein the lower reflective display layer further comprises a total reflection structure located between the first electrode and the bottom plate of the middle transmissive display layer. 12 . The display device according to claim 11 , wherein a refractive index of the total reflection structure is greater than a refractive index of the electrophoretic medium of the lower reflection type display layer.

13. The display device according to claim 2 or 7, wherein the upper transmissive display layer further comprises an upper light-transmissive cover plate, and in the upper transmissive display layer, the electrophoretic medium is located between the upper light-transmissive cover plate and the bottom plate. 14 . The display device according to claim 13 , wherein the middle transmissive display layer further comprises a first light-transmissive cover plate, and in the middle transmissive display layer, the electrophoretic medium is located between the first light-transmissive cover plate and the bottom plate. 15 . The display device according to claim 13 , wherein the lower reflective display layer further comprises a second light-transmitting cover plate, and in the lower reflective display layer, the electrophoretic medium is located between the second light-transmitting cover plate and the bottom plate. 16 . The display device as claimed in claim 1 , wherein each of the display layers further comprises a light shielding pattern located on the second electrode. 17 . The display device according to claim 1 , wherein a total area of ​​the second electrodes of the upper transmissive display layer, the middle transmissive display layer or the lower reflective display layer is 5% to 45% of a total area of ​​the display device.

18. The display device according to claim 1, further comprising a dielectric layer located between the first electrode, the second electrode and the electrophoretic medium.

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