Quantum dot electrophoresis display device

Abstract

The invention discloses a quantum dot electrophoretic display device, which relates to the field of electrophoretic display and comprises a light-emitting side substrate, a backlight side substrate and display pixel units arranged in an array, each display pixel unit comprises a front ultraviolet light source, a first electrophoresis driving electrode, a second electrophoresis driving electrode and a pixel cavity arranged between the first electrophoresis driving electrode and the second electrophoresis driving electrode, and the pixel cavity is filled with electrophoresis display ink; the electrophoretic display ink comprises first quantum dot composite electrophoretic particles, second electrophoretic particles and a dispersion medium, when a first driving signal is applied between the first electrophoresis driving electrode and the second electrophoresis driving electrode, the first quantum dot composite electrophoresis particles are located on the light emitting side relative to the second electrophoresis particles, the front ultraviolet light source is driven to emit ultraviolet light, and the first quantum dot composite electrophoresis particles are activated to perform photoluminescence. The quantum dots are excited by ultraviolet, so that the brightness and the contrast ratio of the electrophoretic display device are effectively improved, and the color expressive force of electrophoretic display can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum dot display, in particular to a quantum dot electrophoretic display device. BACKGROUND

[0002] Electrophoretic display is a paper-like display technology developed earlier, which uses charged balls of different colors to move in a liquid environment by an external electric field to present different color display effects. Its representative manufacturers include E-Ink and Sipix. The high-speed response liquid display (QR-LPD) developed by Bridgestone in Japan has a similar working principle to EPD, but its imaging substance is not charged balls, but black and white powders moving between electric fields to produce display effects.

[0003] The traditional electrophoretic display has the following problems: (1) limited color performance: low color gamut coverage, unable to present high saturation colors; (2) insufficient contrast and brightness: dependent on environmental light reflection, contrast is greatly affected by environmental light, and cannot actively emit light, with low upper limit of brightness; (3) obvious viewing angle dependence: the color and brightness displayed on the light-emitting side at different viewing angles are offset, thereby affecting the multi-viewing angle experience.

[0004] Quantum dots are a kind of zero-dimensional nanometer-scale material with high color purity, wide color gamut coverage, high brightness and high light-emitting efficiency, and adjustable light-emitting wavelength. Introducing quantum dots into electrophoretic particles is expected to promote the development of electronic paper to full-color, dynamic and flexible. In the prior art, there are relatively few studies on quantum dot-based electrophoretic display technology, and there are few related technical solutions. SUMMARY

[0005] In view of the above-mentioned part of the defects of the prior art, the technical problem to be solved by the present application is to provide a quantum dot electrophoretic display device and a control method, aiming to improve the brightness and color performance of electrophoretic display.

[0006] To achieve the above-mentioned purpose, the present application provides a quantum dot electrophoretic display device, which comprises a light-emitting side substrate, a backlight side substrate, and an array of display pixel units.

[0007] The display pixel unit comprises:

[0008] a front ultraviolet light source, a first electrophoretic driving electrode arranged on the light-emitting side substrate;

[0009] a second electrophoretic driving electrode arranged on the backlight side substrate;

[0010] and a pixel cavity arranged between the first electrophoretic driving electrode and the second electrophoretic driving electrode, the pixel cavity being filled with electrophoretic display ink;

[0011] The display pixel unit is adjacent to the display pixel unit, and the display pixel unit is separated by a pixel cavity; the electrophoretic display ink comprises first quantum dot composite electrophoretic particles, second electrophoretic particles, and a dispersion medium.

[0012] When a second driving signal is applied between the first electrophoretic driving electrode and the second electrophoretic driving electrode, the second electrophoretic particles are located on the light-emitting side relative to the first quantum dot composite electrophoretic particles.

[0013] When a first driving signal is applied between the first electrophoretic driving electrode and the second electrophoretic driving electrode, the first quantum dot composite electrophoretic particles are located on the light-emitting side relative to the second electrophoretic particles, and the front ultraviolet light source is driven to emit ultraviolet light and activate the first quantum dot composite electrophoretic particles to emit light.

[0014] In the technical solution, the front ultraviolet light source is arranged on the light-emitting side; the purpose is that if the ultraviolet light source is arranged on the backlight side as a backlight source, the fluorescence emitted by the quantum dots excited cannot be seen on the light-emitting side; specifically, if the ultraviolet light source is arranged as a backlight source, when the second electrophoretic particles are on the light-emitting side and the first quantum dot composite electrophoretic particles are on the backlight side, the ultraviolet light excitation of the quantum dots to emit light is blocked by the second electrophoretic particles above; when the second electrophoretic particles are on the backlight side and the first quantum dot composite electrophoretic particles are on the light-emitting side, the second electrophoretic particles block the ultraviolet light excitation of the first quantum dot composite electrophoretic particles to emit light. Therefore, the ultraviolet light is arranged on the light-emitting side, and a component for filtering out ultraviolet light can be arranged. The technical solution effectively improves the brightness, contrast, and color performance of the electrophoretic display device by exciting the quantum dots with ultraviolet light.

[0015] In addition, it is worth mentioning that one of the first electrophoretic driving electrode and the second electrophoretic driving electrode can be a common electrode; as a common electrode, different pixel points can be connected in common by using a surface electrode.

[0016] In a specific embodiment, the light-emitting side substrate is borosilicate glass, which is used to block the ultraviolet light emitted by the front ultraviolet light source from being emitted from the light-emitting side substrate and achieve high transparency.

[0017] In a specific embodiment, the display pixel unit further comprises a filter arranged between the first electrophoretic driving electrode and the pixel cavity, and the filter is used to block the ultraviolet light emitted by the front ultraviolet light source from being emitted from the light-emitting side substrate.

[0018] In the technical solution, the filter film is arranged to reduce the influence of the front ultraviolet light source of the device structure on the eyesight of the user, and to prevent ultraviolet light and display color crosstalk.

[0019] In an embodiment, the filter is a wavelength selective reflective transmission film which can transmit natural light and reflect ultraviolet light from the display device to the viewer direction to avoid the ultraviolet light from the light emitting side.

[0020] In an embodiment, the filter is a wavelength selective reflective transmission film which can transmit red light or green light or blue light corresponding to the display pixel unit, as shown, and reflect ultraviolet light to avoid the ultraviolet light from the light emitting side. Figure 2

[0021] Typically, the light emitting side substrate can be selected from ITO glass substrate, borosilicate glass, etc.

[0022] The front ultraviolet light source emits ultraviolet light to the pixel cavity direction to excite the first quantum dot composite electrophoretic particles to emit high brightness, high chroma and wide color gamut RGB base color fluorescence; at the same time, the ultraviolet light on the light emitting side is filtered by the filter or the light emitting side substrate, and only the colored visible light is emitted.

[0023] The first electrophoretic driving electrode and the second electrophoretic driving electrode are conductive materials with high light transmittance and adjustable resistivity, including one or more of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), molybdenum-doped indium oxide (IMO), conductive polymers (such as PEDOT:PSS), carbon nanotubes (CNT), graphene film, nanosilver wire or copper wire mesh, and MXene. The relative voltage of each first electrophoretic driving electrode and second electrophoretic driving electrode is controlled to adjust the gray value of the display pixel unit.

[0024] The electrophoretic display ink includes the first quantum dot composite electrophoretic particles, the second electrophoretic particles, and the dispersion medium, and optionally further includes a dispersion stabilizer and a charge control agent.

[0025] In an embodiment, the first quantum dot composite electrophoretic particles are composite particles obtained by coating the same color series pigment with quantum dots after a series of physical and chemical modifications; the quantum dots are one or more of core / shell structure colloidal quantum dots or cesium lead halide perovskite quantum dots; the pigment particles are color sub-micron scale organic / inorganic spherical particles of the same color series as the luminescent quantum dots; and the second electrophoretic particles are electrophoretic particles obtained by physical and chemical modification of pigments.

[0026] The dispersion medium is a non-polar organic solvent with the same or similar density and refractive index as the electrophoretic particles. The dispersion stabilizer and the charge control agent are one or more of anionic, cationic and non-ionic surfactants.

[0027] ​The pixel wall of the pixel cavity is a polymer material with adjustable thickness, good weather resistance and anti-aging, including one or more of photoresist, ultraviolet curing glue, optical clear adhesive (OCA), optical elastomer (OCR) and siloxane polymer.

[0028] In a specific embodiment, the ratio of quantum dots to the same color system pigment of the first quantum dot composite electrophoretic particle (i.e. the amount of quantum dots introduced on the surface of the pigment particle) is: the mass ratio of the quantum dots to the pigment particles is 1:100-1:1.

[0029] In a specific embodiment, the electrophoretic display ink further comprises: a dispersion stabilizer and a charge control agent; wherein the addition amount of the dispersion stabilizer and the charge control agent, and optionally, the mass ratio of the addition amount of octadecylamine to the pigment particles is 1-20 wt.%, and the mass ratio of Span80, T-151 and CH-5 in the dispersion medium is 0.01-10 wt.%.

[0030] In a specific embodiment, the mass ratio of the first quantum dot composite electrophoretic particle to the second electrophoretic particle is 1:20-1:1.

[0031] In this technical solution, the color and chroma of the ultraviolet excited quantum dot luminescence are controlled by the ratio of quantum dots to the same color system pigment; typically, in this embodiment, the ratio of quantum dots to the same color system pigment, the addition amount of dispersion stabilizer and charge control agent, the ratio of electrophoretic particles of different colors, the selection of dispersion medium, the concentration of electrophoretic particles, the thickness of pixel wall, the size of pixel display unit, the resistivity selection of electrode, the driving voltage and driving waveform design, etc. are controlled, so as to realize the optimization of the display effect of electronic paper.

[0032] In a specific embodiment, the dispersion medium is Isopar-G, Isopar-L, Isopar-M, tetrachloroethylene, and a mixed solvent compounded in a ratio of 1:9-9:1.

[0033] In a specific embodiment, the ratio of the total mass of the first quantum dot composite electrophoretic particle and the second electrophoretic particle to the volume of the dispersion medium is 0.1-100 mg mL -1 .

[0034] In this embodiment, by controlling the concentration of the electrophoretic particles, different gray scale display effects can be realized between the pixel units of the device.

[0035] Optionally, the thickness of the pixel wall between adjacent pixel cavities is 10-500 μm, preferably 40-200 μm; preferably, the size of the pixel display unit is 10 mm x 10 mm-50 mm x 50 mm;

[0036] Optionally, the electrode resistivity is 5-15 Ω·m.

[0037] The driving voltage duty cycle of the electrophoretic particle activation stage is 1:1, and the duration is optionally 5-1000 ms, and the voltage is 5-200 V; the driving voltage of the writing stage is 5-200 V, and is preferably 10-100 V.

[0038] Optionally, the driving waveform comprises one or more of a square wave, a sawtooth wave, a sine wave, a triangular wave, a trapezoidal wave, a ladder wave and a hybrid waveform, and the duty cycle is 1:9-9:1.

[0039] The present application has the following advantages: 1. The present application effectively improves the brightness and contrast of the electrophoretic display device by exciting the quantum dots with ultraviolet light, and effectively improves the color performance of the electrophoretic display. 2. The front ultraviolet light source is arranged on the light-emitting side; the purpose is that if the ultraviolet light source is arranged on the backlight side as a backlight, the fluorescence emitted by the excited quantum dots cannot be seen on the light-emitting side; specifically, if the ultraviolet light source is arranged as a backlight, when the second electrophoretic particles are on the light-emitting side and the first quantum dot composite electrophoretic particles are on the backlight side, the ultraviolet light excitation of the quantum dots is blocked by the second electrophoretic particles above; when the second electrophoretic particles are on the backlight side and the first quantum dot composite electrophoretic particles are on the light-emitting side, the second electrophoretic particles will block the ultraviolet light excitation of the first quantum dot composite electrophoretic particles to emit light. Therefore, the ultraviolet light is arranged on the light-emitting side, and a component for filtering out ultraviolet light can also be arranged. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The structure schematic diagram of the quantum dot electrophoretic display device provided by an embodiment of the present application;

[0041] Figure 2 The different gray scale and full-color display effect schematic diagram of the quantum dot electrophoretic display device in the working state as viewed from the top.

[0042] Figure 3 The display physical map of the quantum dot electrophoretic display device provided by a specific embodiment of the present application;

[0043] Figure 4 The display physical map of the quantum dot electrophoretic display device provided by another specific embodiment of the present application. DETAILED DESCRIPTION

[0044] As Figures 1-4As shown, the present invention discloses a quantum dot electrophoretic display device. Those skilled in the art can refer to the content of this article and appropriately improve the technical details to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments. It is obvious that relevant persons can modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0045] like Figure 1 As shown, in an embodiment of the present invention, a quantum dot electrophoretic display device is provided, wherein the display device includes a light-emitting side substrate 1, a backlight side substrate 2, and display pixel units arranged in an array;

[0046] The display pixel unit includes:

[0047] A front ultraviolet light source 7 and a first electrophoresis driving electrode 3 are provided on the light-emitting side substrate 1;

[0048] A second electrophoresis driving electrode 4 is provided on the backlight-side substrate 2;

[0049] and a pixel cavity 8 provided between the first electrophoretic driving electrode 3 and the second electrophoretic driving electrode 4, wherein the pixel cavity 8 is filled with the electrophoretic display ink 5;

[0050] Wherein, adjacent display pixel units are separated by pixel cavities 8; the electrophoretic display ink 5 includes first quantum dot composite electrophoretic particles 9, second electrophoretic particles 10, and a dispersion medium;

[0051] When a first driving signal is applied between the first electrophoretic driving electrode 3 and the second electrophoretic driving electrode, the first quantum dot composite electrophoretic particle 9 is located at the light-emitting side relative to the second electrophoretic particle 10, driving the front ultraviolet light source 7 to emit ultraviolet light and activating the first quantum dot composite electrophoretic particle 9 to photoluminesce;

[0052] When a second driving signal is applied between the first electrophoretic driving electrode 3 and the second electrophoretic driving electrode, the second electrophoretic particles 10 are located at the light-emitting side relative to the first quantum dot composite electrophoretic particles 9 .

[0053] In the embodiment, the front ultraviolet light source is arranged on the light emitting side; the purpose is that if the ultraviolet light source is arranged on the backlight side as a backlight, the fluorescent light emitted by the quantum dots excited cannot be seen on the light emitting side; specifically, if the ultraviolet light source is arranged as a backlight, when the second electrophoretic particles 10 are on the light emitting side and the first quantum dot composite electrophoretic particles 9 are on the backlight side, the ultraviolet light excited quantum dot luminescence is blocked by the second electrophoretic particles 10 above; when the second electrophoretic particles 10 are on the backlight side and the first quantum dot composite electrophoretic particles 9 are on the light emitting side, the second electrophoretic particles 10 will block the ultraviolet light excited first quantum dot composite electrophoretic particles to emit light. Therefore, the ultraviolet light is arranged on the light emitting side, and a component for filtering ultraviolet light can be arranged at the same time.

[0054] In addition, it is worth mentioning that one of the first electrophoretic driving electrode 3 and the second electrophoretic driving electrode 4 can be a common electrode; as a common electrode, the surface electrodes of different pixel points can be shared.

[0055] It is worth mentioning that when the light emitting side substrate 1 does not use borosilicate glass or a substrate that can block ultraviolet light, the display pixel unit can further comprise a filter arranged between the first electrophoretic driving electrode 3 and the pixel cavity 8, the filter being used to block the ultraviolet light emitted by the front ultraviolet light source 7 from emitting from the light emitting side substrate 1. Optionally, the filter is a wavelength selective reflection transmission film, which can project natural light and reflect ultraviolet light from the display device to the viewer. In another optional example, the filter is a wavelength selective reflection transmission film, which can project red light or green light or blue light corresponding to the display pixel unit and reflect ultraviolet light from the display device to the viewer.

[0056] In addition, typically, the light emitting side substrate 1 can be selected from ITO glass substrate, borosilicate glass, etc. Typically, the quantum dots are coated on the surface of the pigment particles as electrophoretic particles, and the front ultraviolet light source 7 and the electrophoretic display unit are stacked and packaged by 3D, the light emitting side is borosilicate glass with high light transmittance, which directly filters ultraviolet light and does not need to additionally arrange ultraviolet light blocking components.

[0057] The front ultraviolet light source 7 emits ultraviolet light to the pixel cavity 8 direction, excites the first quantum dot composite electrophoretic particles 9 to emit high brightness, high chroma and wide color gamut RGB base color fluorescent light; at the same time, the ultraviolet light on the light emitting side is filtered by the filter or the light emitting side substrate 1, and only the colored visible light is emitted.

[0058] The first electrophoretic driving electrode 3 and the second electrophoretic driving electrode 4 are conductive materials with high light transmittance and adjustable resistivity, including one or more of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), molybdenum-doped indium oxide (IMO), conductive polymers (such as PEDOT:PSS), carbon nanotubes (CNT), graphene film, nano-silver wire or copper wire grid, and MXene. The relative voltage of each first electrophoretic driving electrode 3 and second electrophoretic driving electrode 4 is controlled to regulate the gray value of the display pixel unit.

[0059] The electrophoretic display ink 5 includes the first quantum dot composite electrophoretic particle 9, the second electrophoretic particle 10, and a dispersion medium, and optionally further includes a dispersion stabilizer and a charge control agent.

[0060] In this embodiment, the first quantum dot composite electrophoretic particle 9 is a composite particle obtained by coating the same-color pigment with quantum dots after a series of physical and chemical modifications; the quantum dots are one or more of core / shell structure colloidal quantum dots or cesium lead halide perovskite quantum dots; the pigment particle is a color sub-micron scale organic / inorganic spherical particle of the same color as the luminescent quantum dot; and the second electrophoretic particle 10 is an electrophoretic particle obtained by physical and chemical modification of the pigment.

[0061] The dispersion medium is a non-polar organic solvent with the same or similar density and refractive index as the electrophoretic particles. The dispersion stabilizer and the charge control agent are one or more of anionic, cationic, and non-ionic surfactants.

[0062] The pixel wall 6 of the pixel cavity 8 is a polymer material with adjustable thickness, good weather resistance, and anti-aging properties, including one or more of photoresist, ultraviolet curing glue, optical clear adhesive (OCA), optical elastomer (OCR), and siloxane polymer.

[0063] In this embodiment, the ratio of quantum dots to same-color pigment (i.e., the amount of quantum dots introduced to the surface of the pigment particle) of the first quantum dot composite electrophoretic particle 9 is that the mass ratio of the quantum dots to the pigment particles is 1:100-1:1.

[0064] In this embodiment, the electrophoretic display ink 5 further includes a dispersion stabilizer and a charge control agent; and the optional mass ratio of the added amount of octadecylamine to the pigment particles is 1-20 wt.%, and the mass ratio of Span80, T-151, and CH-5 in the dispersion medium is 0.01-10 wt.%.

[0065] In this embodiment, the mass ratio of the first quantum dot composite electrophoretic particle 9 to the second electrophoretic particle 10 is 1:20-1:1.

[0066] In the embodiment, the color and chroma of the light emitted by the quantum dots under the excitation of ultraviolet light are controlled by the ratio of the quantum dots to the same-color pigments; typically, in the embodiment, the ratio of the quantum dots to the same-color pigments, the added amount of the dispersion stabilizer and the charge control agent, the ratio of the electrophoretic particles of different colors, the selection of the dispersion medium, the concentration of the electrophoretic particles, the thickness of the pixel wall 6, the size of the pixel display unit, the resistivity selection of the electrode, the driving voltage and the driving waveform design, etc. are controlled, so as to realize the optimization of the display effect of the electronic paper.

[0067] In the embodiment, the dispersion medium is Isopar-G, Isopar-L, Isopar-M, tetrachloroethylene and a mixed solvent compounded in a ratio of 1:9 to 9:1.

[0068] In the embodiment, the ratio of the total mass of the first quantum dot composite electrophoretic particles 9 and the second electrophoretic particles 10 to the volume of the dispersion medium is 0.1 to 100 mg / mL. -1 .

[0069] In the embodiment, by controlling the concentration of the electrophoretic particles, different gray display effects can be realized between the pixel units of the device.

[0070] Optionally, the thickness of the pixel wall 6 between adjacent pixel cavities 8 is 10 to 500 μm, and preferably 40 to 200 μm; preferably, the size of the pixel display unit is 10 mm x 10 mm to 50 mm x 50 mm.

[0071] Optionally, the resistivity of the electrode is 5 to 15 Ω.m.

[0072] The duty cycle of the driving voltage in the activation stage of the electrophoretic particles is 1:1, and optionally, the duration is 5 to 1000 ms, and the voltage size is 5 to 200 V; optionally, the driving voltage size in the writing stage is 5 to 200 V, and preferably 10 to 100 V.

[0073] Optionally, the driving waveform includes one or more of a square wave, a sawtooth wave, a sine wave, a triangular wave, a trapezoidal wave, a ladder wave and a hybrid waveform, and the duty cycle is 1:9 to 9:1.

[0074] The embodiment provides a quantum dot electrophoretic display device and a control method, which systematically optimizes the display effect of the device through device structure design, display ink formula control and driving electric field design, so as to meet diversified display requirements.

[0075] In the optional case in the embodiment, the quantum dots are coated on the surface of the pigment particles as electrophoretic particles. In the device structure, the front ultraviolet light source 7 is stacked with the electrophoretic display unit by 3D packaging, and the light-emitting side substrate 1 is borosilicate glass with high light transmittance, which directly filters ultraviolet light and does not need to additionally set an ultraviolet blocking component.

[0076] Embodiment 1

[0077] In the first embodiment of the application, the provided quantum dot electrophoretic display device is based on permanent red F5R and CdSe / CdZnSe / CdZnS / ZnS / CdZnS quantum dot composite electrophoretic particles and titanium dioxide electrophoretic particles.

[0078] The display ink formula is as follows: the mass ratio of red quantum dots to permanent red F5R is 1:5; the mass ratio of the added amount of octadecylamine to the pigment particles is 8wt.%; the mass ratio of Span80, T-151 and CH-5 in the dispersion medium is 2wt.%; the mass ratio of red composite electrophoretic particles to white electrophoretic particles is 1:10; the dispersion medium is Isopar-M; and the concentration of the electrophoretic particles, i.e. the ratio of the total mass of red composite electrophoretic particles and white electrophoretic particles to the volume of Isopar-M, is 13mg mL -1 .

[0079] The device structure design is as follows: the electrode resistivity is selected to be 7-11Ω·m; the thickness of the pixel wall 6 is selected to be 200μm; and the size of the pixel display unit is selected to be 50mm×50mm.

[0080] The driving electric field design is as follows: the driving voltage duty ratio of the electrophoretic particle activation stage is 1:1, the duration is 500ms, and the voltage size is 70V. The driving voltage size of the writing stage is 70V, the driving waveform is selected to be a square wave, and the duty ratio is 7:3.

[0081] As Figure 3 shown, it is a real device picture of the red unit of the device of embodiment 1.

[0082] Embodiment 2

[0083] In the second embodiment of the application, the provided quantum dot electrophoretic display device is based on iron oxide green and CdSeS / CdZnS / ZnS quantum dot composite electrophoretic particles and titanium dioxide electrophoretic particles.

[0084] The display ink formula regulation: the mass ratio of green quantum dots and green iron oxide is 1:4; the mass ratio of Span 85 and CH-5 in the dispersion medium is 2wt.%; the mass ratio of green composite electrophoretic particles and white electrophoretic particles is 1:6; the dispersion medium is Isopar-M; the concentration of electrophoretic particles, i.e. the ratio of the total mass of green composite electrophoretic particles and white electrophoretic particles to the volume of Isopar-M, is 16mg mL -1 .

[0085] Device structure design: the electrode resistivity is selected to be 7-11Ω·m; the thickness of the pixel wall 6 is selected to be 100μm; and the size of the pixel display unit is selected to be 50mm×50mm.

[0086] Driving electric field design: the driving voltage duty ratio of the electrophoretic particle activation stage is 1:1, the duration is 500ms, and the voltage size is 50V. The driving voltage size of the writing stage is 50V, the driving waveform is selected to be a square wave, and the duty ratio is 6:4.

[0087] As shown in FIG. 2, it is a display real object diagram of the green unit of the device of Example 1. Figure 4

[0088] It should be noted that, in this document, the relationship terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or sequence between the entities or operations. Moreover, the terms “include”, “contain” or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement “including a…” does not exclude the presence of another identical element in the process, method, article or equipment including the element.

[0089] Each of the embodiments in the specification is described in a relevant manner, and the same and similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. Especially, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment.

[0090] The above are only the preferred embodiments of the present application, and are not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.​

Claims

1. A quantum dot electrophoretic display device, characterized in that: The display device includes a light-emitting side substrate, a backlight side substrate, and display pixel units arranged in an array; The display pixel unit includes: A front ultraviolet light source and a first electrophoresis driving electrode are provided on the light-emitting side substrate; a second electrophoresis driving electrode disposed on the backlight-side substrate; and a pixel cavity provided between the first electrophoretic driving electrode and the second electrophoretic driving electrode, wherein the pixel cavity is filled with electrophoretic display ink; Wherein, adjacent display pixel units are separated by pixel cavities; the electrophoretic display ink comprises first quantum dot composite electrophoretic particles, second electrophoretic particles, and a dispersion medium; When a first driving signal is applied between the first electrophoretic driving electrode and the second electrophoretic driving electrode, the first quantum dot composite electrophoretic particle is located at the light-emitting side relative to the second electrophoretic particle, driving the front ultraviolet light source to emit ultraviolet light and activating the first quantum dot composite electrophoretic particle to photoluminesce; When a second driving signal is applied between the first electrophoretic driving electrode and the second electrophoretic driving electrode, the second electrophoretic particles are located at the light-emitting side relative to the first quantum dot composite electrophoretic particles.

2. A quantum dot electrophoretic display device according to claim 1, characterized in that: The light-emitting side substrate is made of borosilicate glass, and the borosilicate glass is used to block the ultraviolet light emitted by the front ultraviolet light source from being emitted from the light-emitting side substrate and achieve high transmittance.

3. The quantum dot electrophoretic display device according to claim 1, wherein: The display pixel unit further includes a filter disposed between the first electrophoresis drive electrode and the pixel cavity, the filter being used to block the ultraviolet light emitted by the front ultraviolet light source from being emitted from the light-emitting side substrate.

4. A quantum dot electrophoretic display device according to claim 3, characterized in that: The filter is a wavelength selective reflective transmissive film, which can project natural light or red light, green light or blue light corresponding to the display pixel unit from the display device to the viewer, and reflect ultraviolet light.

5. The quantum dot electrophoretic display device according to claim 1, wherein: The first quantum dot composite electrophoretic particles are composite particles obtained by coating quantum dots with pigments of the same color and undergoing a series of physical and chemical modifications; the quantum dots are one or more of core / shell structured colloidal quantum dots or cesium lead halide perovskite quantum dots; the pigment particles are colorful submicron-sized organic / inorganic spherical particles of the same color as the luminescent quantum dots; the second electrophoretic particles are electrophoretic particles obtained by physical and chemical modifications of the pigments.

6. A quantum dot electrophoretic display device according to claim 5, characterized in that: The ratio of the quantum dots of the first quantum dot composite electrophoretic particles to the pigment of the same color is: the mass ratio of the quantum dots to the pigment particles is 1:100 to 1:

1.

7. The quantum dot electrophoretic display device according to claim 5, characterized in that: The electrophoretic display ink further comprises: a dispersion stabilizer and a charge control agent; wherein, the amount of the dispersion stabilizer and the charge control agent added, optionally, the mass ratio of the amount of octadecylamine added to the pigment particles is 1 to 20 wt.%, and the mass proportion of Span80, T-151 and CH-5 in the dispersion medium is 0.01 to 10 wt.%.

8. The quantum dot electrophoretic display device according to claim 1, wherein: The mass ratio of the first quantum dot composite electrophoretic particles to the second electrophoretic particles is 1:20 to 1:

1.

9. The quantum dot electrophoretic display device according to claim 7, wherein: The dispersion medium is Isopar-G, Isopar-L, Isopar-M, tetrachloroethylene and a mixed solvent prepared in a ratio of 1:9 to 9:

1.

10. The quantum dot electrophoretic display device according to claim 7, characterized in that: The ratio of the total mass of the first quantum dot composite electrophoretic particle and the second electrophoretic particle to the volume of the dispersion medium is 0.1 to 100 mg mL -1 .

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