TWM644905U - Display device having micro-type lighting units in backlight thereof - Google Patents

Abstract

The present invention provides a display device, which includes a backlight module including a plurality of micro-light-emitting units, an optical switch layer located above the backlight module, and a filter layer located above the optical switch layer. Each micro-light-emitting unit in the backlight module can be independently controlled to emit light independently. The optical switch layer controls whether the light emitted by the micro-light-emitting unit of the backlight module penetrates or not. The filter layer includes a plurality of quantum dots, and the color of the light emitted by each micro-light-emitting unit is converted by each quantum dot, and multiple sub-pixel units are formed through the quantum dots.

Description

Display device with micro light-emitting unit in backlight

The present invention relates to a display device. More specifically, the present invention relates to a display device with a micro-light-emitting unit in the backlight.

Recently, liquid crystal display devices have been rapidly developed as an important human-computer interface. Portable electronic devices, computers or televisions can display complex messages through liquid crystal display devices.

Based on the advantages of large visible area, compact size and low energy consumption, liquid crystal display (LCD) devices have become increasingly popular and have become mainstream. A conventional liquid crystal display device 100 is shown in FIG. 1 . The liquid crystal display device 100 is arranged from bottom to top and includes a backlight module 111, a first polarizer 112, a first substrate 113, a transistor layer 114, a first electrode 115, a liquid crystal layer 116, a second electrode 117, a filter 118, Two substrates 119 and a second polarizer 120 . Then the operating mechanism of the LCD device 100 is briefly described. The liquid crystal molecules in the liquid crystal layer 116 are twisted when an electric field is applied. One or more transistors in the transistor layer 114 are used to control the twisting direction of the liquid crystal molecules and control the optical switch. The light emitted by the backlight module 111 passes through the first polarizer 112 and the second polarizer 120 to generate different polarization directions. Light combines with the twisting direction of liquid crystal molecules to control brightness changes to form gray scales. The transmission filter 118 forms a plurality of sub-pixels 118a with different colors. By combining multiple sub-pixels 118a, a pixel with full color can be formed, thereby forming colors visible to the human eye. The formation of sub-pixel 118a is defined by each transistor in transistor layer 114. In addition, an alignment film (not shown) may be disposed on the first substrate 113 and the second substrate 119 for aligning liquid crystal molecules. An electric field may be applied to the transistor layer 114 through the first electrode 115 and the second electrode 117 .

However, the power efficiency, brightness, contrast and color uniformity of this liquid crystal display device 100 are low because only a small amount of light emitted from the backlight module 111 can pass through the liquid crystal layer 116 . In addition, the manufacturing process of the transistor layer 114 is complicated, thereby increasing the manufacturing cost. Furthermore, the conventional filter 118 uses colored photoresist to form the structure of the sub-pixels 118a. The colors produced by this method can no longer meet modern demands for high resolution, high brightness, high contrast and wide color gamut.

Therefore, improvements to the above-mentioned liquid crystal display device 100 are still necessary.

The present invention provides a display device with a micro-light-emitting unit in the backlight. Through a filter layer with quantum dots and a backlight module with a micro-light-emitting unit, a wide color gamut, high color uniformity and high color saturation can be obtained.

One object of the present invention is to provide a display device, which includes a backlight module including a plurality of micro-light-emitting units, an optical switch layer located above the backlight module, and a filter layer located above the optical switch layer. Each micro-light-emitting unit in the backlight module can be independently controlled to emit light independently. The optical switch layer controls whether the light emitted by each micro-light-emitting unit of the backlight module penetrates or not. The filter layer includes multiple Quantum dots of different colors, and the color of the light emitted by each micro-light-emitting unit is converted by each quantum dot, and multiple sub-pixel units of different colors are formed through each quantum dot of different colors.

In the above display device, the light colors emitted by the micro-light-emitting units include red, green and blue. At this time, the plurality of quantum dots include red quantum dots, green quantum dots and blue quantum dots, and the color of each quantum dot is correspondingly converted into each micro-light-emitting unit. The color of light emitted by the light-emitting unit.

In the above display device, the light color emitted by the plurality of micro-light-emitting units is single blue. In this case, the plurality of quantum dots include red quantum dots and green quantum dots.

In the above display device, the optical switch layer may include liquid crystal material or electrochromic material.

In the above display device, after the light emitted by the micro backlight module penetrates the optical switch layer, the optical switch layer is controlled to change its light transmittance to adjust the penetration ratio of the light.

The above display device further includes a first polarizer located between the backlight module and the optical switch layer and a second polarizer located on the filter layer.

The above display device further includes a first electrode located between the backlight module and the optical switch layer and a second electrode located between the optical switch layer and the filter layer. The transmittance of the optical switch layer is controlled by the electric field formed between the first electrode and the second electrode.

In the above display device, the wavelength of the light emitted by the micro-light-emitting unit changes as the voltage applied between the first electrode and the second electrode changes, thereby modulating the conversion efficiency of the quantum dots.

In the above display device, a mask is provided between each quantum dot of the filter layer. cover.

In the above display device, the size of each micro light-emitting unit is micron size.

100:Liquid crystal display device

111:Backlight module

112: First polarizer

113: First substrate

114:Transistor layer

115: first electrode

116: Liquid crystal layer

117:Second electrode

118:Optical filter

118a: sub-pixel

119:Second substrate

120: Second polarizer

200:Display device

210:Backlight module

211:Micro light emitting unit

220: Optical switch layer

221:Electrochromic material

222:Electrolyte layer

223:Ion storage layer

230: Filter layer

240:The first polarizer

250: Second polarizer

260: first electrode

270:Second electrode

300: red sub-pixel unit

400: Green sub-pixel unit

500: blue sub-pixel unit

600:Mask

Figure 1 is a schematic structural diagram of a conventional liquid crystal display device;

Figure 2A is a schematic structural diagram of a display device according to an embodiment of the present invention;

Figure 2B is a schematic structural diagram of a display device according to another embodiment of the present invention;

Figure 3A is a schematic diagram showing the complete structure of the optical switch layer in Figure 2A when liquid crystal material is used;

Figure 3B is a schematic diagram of the complete structure of the optical switch layer in Figure 2B when using liquid crystal material;

Figure 4A is a schematic diagram showing the complete structure of the optical switch layer in Figure 2A when using electrochromic material; and

Figure 4B is a schematic diagram of the complete structure of the optical switch layer in Figure 2B when using electrochromic material.

Several embodiments of the present invention will be described below with reference to the drawings. For the sake of clarity, many practical details will be explained together in the following narrative. However, it should be understood that these practical details should not be used to limit the invention. also That is to say, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings and focus on the main technical features of this case, some commonly used and unnecessary structures and components will be shown in a simple schematic manner or omitted in the drawings. In addition, similar components may also be represented by the same number.

In the present invention, the terms "first", "second", "upper", "lower" and "between" are used to describe a relative position. In fact, depending on the actual situation, the possibility of changing the order of arrangement is not ruled out. For example, when the substrate is located on the top layer, the other layer structures may be arranged downward. At this time, the relative positions of "first", "second", "upper" and "lower" may also change accordingly.

Please refer to Figure 2A and Figure 2B together.

A display device 200 includes a backlight module 210 including a plurality of micro light-emitting units 211, an optical switch layer 220 located above the backlight module 210, and a filter layer 230 located above the optical switch layer 220.

Each micro-light-emitting unit 211 in the backlight module 210 can be independently controlled to emit light independently.

The optical switch layer 220 can control whether the light emitted by the micro-light-emitting unit 211 of the backlight module 210 is transmitted or not. In more detail, after the light emitted by the micro-light-emitting unit 211 of the backlight module 210 penetrates the optical switch layer 220, the optical switch layer 220 is controlled to change its light transmittance, thereby adjusting the penetration ratio of the light. By adjusting the penetration ratio of light, the final visual characteristics such as brightness (gray scale) and contrast can be adjusted.

The filter layer 230 includes a plurality of quantum dots 231 with different colors, and the color of the light emitted by each micro-light-emitting unit 211 is determined by each quantum dot 231 The quantum dots 231 of different colors are converted into a plurality of sub-pixel units 300, 400, and 500 of different colors in the filter layer 230.

Quantum dots 231 are small semiconductor crystals with dimensions as low as nanometers. Their properties are very different from bulk semiconductors. The most notable feature of quantum dots 231 is the ability to adjust the semiconductor band gap by changing their size and discrete energy levels (the so-called Quantum Confinement Effect). In addition, when quantum dots 231 are applied to displays, a narrower spectrum can be obtained based on their narrow emission linewidth (eg, emission half-maximum (FWHM) of about 20 to 30 nanometers). Extremely high color saturation can be obtained through the narrow spectrum, which can cover more than 90% of the most stringent Rec.2020 color gamut standard, so the visual effect of a wide color gamut can be obtained. The narrow emission linewidth of quantum dots 231 also makes them suitable as LED backlight components in high-definition displays such as 8K or higher resolution.

The material of the quantum dot 231 may include II-VI group element compounds, III-V group element compounds, perovskite quantum dots, and be formed by coating the above-mentioned II-VI group element compounds and/or III-V group element compounds. Core-shell structure compounds or doped nanocrystalline particles. Among them, II-VI group elements may include cadmium selenide (CdSe), cadmium telluride (CdTe), magnesium sulfide (MgS), magnesium selenide (MgSe), magnesium telluride (MgTe), calcium sulfide (CaS), selenium Calcium sulfide (CaSe), calcium telluride (CaTe), strontium sulfide (SrS), strontium selenide (SrSe), strontium telluride (SrTe), barium sulfide (BaS), barium selenide (BaSe), barium telluride ( BaTe), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe) or cadmium sulfide (CdS), etc.; III-V element compounds can include gallium nitride (GaN), gallium phosphide (GaP ), gallium arsenide (GaAs), indium nitride (lnN), indium phosphide (lnP) or indium arsenide (InAs), etc., but are not limited to the above materials.

The plurality of quantum dots 231 may have colors of red, green, blue, or any combination of the aforementioned colors. The light emitted by the micro-light-emitting unit 211 can excite the quantum dots 231 and convert the quantum dots 231 of different colors to form different light colors, which are finally presented to the human eye to form a color image. It can be understood that a color image is composed of multiple pixel units. Therefore, the above-mentioned quantum dots 231 of different colors can be stacked and arranged to form multiple sub-pixel units 300, 400, and 500 of different colors of the visible image. Quantum dots 231 of different colors can be arranged in different ways to form different color saturations. For example, the quantum dots 231 can be arranged in a square, triangular or mosaic shape to form sub-pixel units 300, 400 and 500 in different arrangements to achieve different color rendering effects.

The above-mentioned quantum dots 231 can be in the form of particles, and the diameter of the particles can be between 1 nanometer and 10 nanometers, and the weight ratio of each quantum dot 231 can be adjusted differently.

The stacked arrangement of each quantum dot 231 can be formed by methods such as inkjet method (Inject), chemical colloidal method (chemical colloidal method), self-assembly method (self-assembly method), lithography and etching method (lithography and etching), or gate separation. method (split-gate approach) and other methods. Through chemical sol method synthesis, multilayered quantum dots 231 can be produced. The process is simple and suitable for mass production. The self-assembly method can use a chemical vapor deposition process to allow the quantum dots 231 to self-grow on the surface of a specific substrate, thereby mass-producing regularly arranged quantum dots 231. Lithography and etching uses a light beam or electron beam to directly etch a substrate to create the desired pattern. The split-gate approach generates a two-dimensional quantum well plane by applying an external voltage. Limitation, the shape and size of the quantum dot 231 can be changed.

In different embodiments, the micro light-emitting unit 211 can emit different light colors to be combined into different colors of backlight, and converted into different light colors through quantum dots 231 of different colors.

In the embodiment of Figure 2A, the light colors emitted by the micro-light-emitting unit 211 include red, green and blue. At this time, the plurality of quantum dots 231 include red quantum dots, green quantum dots and blue quantum dots, and each quantum dot 231 has The color corresponds to the color of light emitted by each micro-light-emitting unit 211. In other words, the red light emitted by the micro light-emitting unit 211 is converted into red light through the red quantum dots, the green light emitted by the micro light-emitting unit 211 is converted into green light through the green quantum dots, and the blue light emitted by the micro light-emitting unit 211 is converted into green light through the green quantum dots. It is converted into blue light, and then the red light converted through the red quantum dots forms the red sub-pixel unit 300, the green light converted through the green quantum dots forms the green sub-pixel unit 400, and the blue light converted through the blue quantum dots forms the blue sub-pixel unit 300. The pixel unit 500 can then form a full-color light color.

In the embodiment of Figure 2B, the light color emitted by the micro-light-emitting unit 211 is single blue. At this time, the quantum dots 231 in the filter layer 230 include red quantum dots and green quantum dots respectively corresponding to the micro-light-emitting unit 211, and the filter layer 230 There are no blue quantum dots 231 in 230 . In other words, part of the blue light emitted by the micro light-emitting unit 211 is converted into red light through the red quantum dots to form the red sub-pixel unit 300, part of it is converted into green light through the green quantum dots to form the green sub-pixel unit 400, and part of it is not passed through. The quantum dots convert and directly emit blue light to form the blue sub-pixel unit 500, thereby forming a full-color light color. In this embodiment, the light color emitted by the micro-light-emitting unit 211 can also be single purple.

In the above display device 200, a mask 600 can be provided between the sub-pixel units 300, 400, and 500 formed by each quantum dot 231 of the filter layer 230, which can block the interference between the sub-pixel units 300, 400, and 500. Astigmatize light, avoid light mixing, and ensure uniformity and saturation of light. The mask 600 is usually made of black light-absorbing material, but is not limited to this.

The optical switch layer 220 can control the light transmission ratio emitted by the micro-light-emitting unit 211 of the backlight module 210 to control optical properties such as brightness (gray scale) and contrast. The optical switch layer 220 may be made of liquid crystal material or electrochromic material.

When the optical switch layer 220 is made of liquid crystal material, please refer to Figure 3A and Figure 3B for examples of the complete structure of the display device 200 . Compared with the aforementioned embodiments in Figures 2A and 2B, in the embodiments in Figures 3A and 3B, the display device 200 further includes a first polarizer 240 between the backlight module 210 and the optical switch layer 220; A second polarizer 250 located on the filter layer 230. At the same time, the display device 200 also includes a first electrode 260 between the backlight module 210 and the optical switch layer 220 and a second electrode 270 between the optical switch layer 220 and the filter layer 230 . The transmittance of the optical switch layer 220 is controlled by the electric field formed between the first electrode 260 and the second electrode 270 to form a required gray scale.

In the above-mentioned display device 200, the size of each micro-light-emitting unit 211 can be millimeters or less, preferably micron size. The micro-light-emitting unit 211 usually uses an inorganic light-emitting diode (LED), which is a discontinuous point light source, thus causing a problem of insufficient backlight uniformity. Moreover, due to the innate luminous characteristics of point light sources, visual defects such as light leakage, low contrast, and poor color saturation are caused. In order to solve the above problem, one way is to reduce the size of each micro-light-emitting unit 211 so as to place more micro-light-emitting units 211 in the same area, hoping to achieve a luminous effect similar to that of a surface light source. This new model further introduces quantum dots 231 of different colors into the filter layer 230, which are matched with the micro-light-emitting units 211 reduced in size to micron size. At the same time, the color saturation and color gamut can be improved to cope with future high-definition displays. Device requirements.

In Figure 3A, the light colors emitted by the micro light-emitting unit 211 include red, green and blue. At this time, the plurality of quantum dots 231 include red quantum dots, green quantum dots and blue quantum dots. The light emitted by the micro-light-emitting unit 211 is converted through red quantum dots to form a red sub-pixel unit 300, the green light converted through green quantum dots forms a green sub-pixel unit 400, and the blue light converted through blue quantum dots forms a blue sub-pixel unit. Unit 500. A mask 600 is provided between each pixel unit 300, 400, and 500 to block stray light. In Figure 3B, no blue quantum dots are provided. The micro-light-emitting unit 211 emits a single blue light. Part of the light emitted by the micro-light-emitting unit 211 is converted by red quantum dots to form the red sub-pixel unit 300, and part of the light is converted by green quantum dots to form the green sub-pixel unit 400, but part of the light is blue. The light is directly emitted to form the blue sub-pixel unit 500 without any quantum dot conversion.

When the optical switch layer 220 is made of electrochromic material, please refer to Figure 4A and Figure 4B for examples of the complete structure of the display device 200 . Compared with the aforementioned embodiments in Figures 2A and 2B, in the embodiments in Figures 4A and 4B, the display device 200 further includes a first polarizer 240 between the backlight module 210 and the optical switch layer 220; A second polarizer 250 located on the filter layer 230. At the same time, the display device 200 also includes a first electrode 260 between the backlight module 210 and the optical switch layer 220 and a second electrode 270 between the optical switch layer 220 and the filter layer 230 . The transmittance of the optical switch layer 220 is also controlled by the electric field formed between the first electrode 260 and the second electrode 270 to form a required gray scale. Also based on Based on the electrochromic principle, the optical switch layer 220 in Figure 4A is composed of an electrochromic material 221, an electrolyte layer 222 and an ion storage layer 223 arranged from top to bottom.

When an external voltage is applied to the first electrode 260 and the second electrode 270, an electric field is formed therebetween, and an oxidation-reduction reaction occurs under the action of the electric field, causing the electrochromic material 221 to change color and form a transparent state, which can make the micro-light-emitting unit 211 light penetration. To be more specific, the electrons provided by the electrode layer and the ions inside the ion storage layer 223 and the electrolyte layer 222 cause the structure of the electrochromic material 221 to change and change color through a redox reaction. The degree of discoloration can be The required gray level is controlled by controlling the electric field formed between the first electrode 260 and the second electrode 270 .

In Figure 4A, the light colors emitted by the micro light-emitting unit 211 include red, green and blue. At this time, the plurality of quantum dots 231 include red quantum dots, green quantum dots and blue quantum dots. The light emitted by the micro-light-emitting unit 211 is converted through red quantum dots to form a red sub-pixel unit 300, the green light converted through green quantum dots forms a green sub-pixel unit 400, and the blue light converted through blue quantum dots forms a blue sub-pixel unit. Unit 500. A mask 600 is provided between each pixel unit 300, 400, and 500 to block stray light. In Figure 4B, no blue quantum dots are provided. The micro-light-emitting unit 211 emits a single blue light. Part of the light emitted by the micro-light-emitting unit 211 is converted by red quantum dots to form the red sub-pixel unit 300, and part of the light is converted by green quantum dots to form the green sub-pixel unit 400, but part of the light is blue. The light is directly emitted to form the blue sub-pixel unit 500 without any quantum dot conversion.

To sum up, the light emitted by the micro light-emitting unit 211 of the backlight module 210 can excite the quantum dots 231 of various colors and convert the light color to form specific There are sub-pixel units 300, 400, 500 with red, green, blue or any combination of the aforementioned colors, thereby forming a full-color image, and through the narrow emission linewidth characteristics of the quantum dots 231, uniform luminescence and broad spectrum are formed. color gamut. Furthermore, in one embodiment, the wavelength of the light emitted by the micro-light-emitting unit 211 can change as the voltage applied between the first electrode 260 and the second electrode 270 changes, thereby modulating the excitation of the quantum dots 231 of different colors. efficiency. This is because the quantum dots 231 of different colors respond differently to the wavelength of the excitation light source, and as the applied voltage changes, the wavelength of the light emitted by the micro-light-emitting unit 211 will be blue-shifted (the wavelength peak shifts to a shorter wavelength) or Changes in red shift (wavelength peak shifts toward longer wavelengths), therefore the excitation efficiency of quantum dots 231 of different colors also changes accordingly.

According to the above, the display device 200 disclosed in the present invention, through the material properties of the quantum dots 231 and the reduced size of the micro-light-emitting unit 211, can achieve higher light conversion efficiency, higher brightness, higher contrast, higher color saturation, Wider viewing angles and wider color gamut. Furthermore, the use of electrochromic materials for the optical switch layer 220 also provides another alternative to the conventional use of liquid crystal materials, providing another innovative structure that reduces manufacturing costs and achieves different effects.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone familiar with this art can make various modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention is The scope shall be determined by the appended patent application scope.

200:Display device

210:Backlight module

211:Micro light emitting unit

220: Optical switch layer

230: Filter layer

231:Quantum dots

300: red sub-pixel unit

400: Green sub-pixel unit

500: blue sub-pixel unit

600:Mask

Claims (11)

A display device including: A backlight module including a plurality of micro-light-emitting units, wherein each of the micro-light-emitting units is independently controlled to emit light independently; An optical switch layer located above the backlight module, which controls whether the light emitted by each of the micro-light-emitting units of the backlight module passes through; and A filter layer located above the optical switch layer, wherein the filter layer includes a plurality of quantum dots with different colors, and the color of the light emitted by each of the micro-light-emitting units is converted by each of the quantum dots, and A plurality of sub-pixel units with different colors are formed through each of the quantum dots with different colors. As in the display device described in item 1 of the patent application, the light colors emitted by the micro-light-emitting unit include red, green and blue, and the plurality of quantum dots include red quantum dots, green quantum dots and blue quantum dots. Quantum dots, and the color of each quantum dot correspondingly converts the color of light emitted by each of the micro-light-emitting units. For the display device described in Item 1 of the patent application, the light color emitted by the plurality of micro-light-emitting units is single blue, and in this case, the plurality of quantum dots include red quantum dots and green quantum dots. For the display device described in claim 1 of the patent application, the optical switch layer includes a liquid crystal material. For the display device described in claim 1 of the patent application, the optical switch layer includes an electrochromic material. The display device as described in item 1 of the patent application, wherein after the light emitted by the micro backlight module penetrates the optical switch layer, the optical switch layer is controlled to change its light transmittance to adjust the The penetration ratio of light. The display device as described in item 1 of the patent application further includes: a first polarizer located between the backlight module and the optical switch layer; and a second polarizer located above the filter layer. piece. The display device as described in item 1 of the patent application further includes: a first electrode located between the backlight module and the optical switch layer; and a first electrode located between the optical switch layer and the filter layer The second electrode between them; wherein the transmittance of the optical switch layer is controlled by the electric field formed between the first electrode and the second electrode. As in the display device described in item 8 of the patent application, the wavelength of the light emitted by the micro-light-emitting unit changes with the change of the voltage applied between the first electrode and the second electrode, thereby modulating the Quantum dot conversion efficiency. For the display device described in claim 1 of the patent application, a mask is provided between each quantum dot of the filter layer. For the display device described in Item 1 of the patent application, the size of each of the micro-light-emitting units is micron size.

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