Display device based on carbon nano tube and manufacturing method

Abstract

The invention discloses a display device based on a carbon nano tube, which comprises an LED backlight, an array substrate and a liquid crystal layer from bottom to top, and is characterized in that the LED backlight provides a white light source; the array substrate comprises a TFT (Thin Film Transistor) control array made of a carbon nanotube material and a color film matrix covering the TFT control array, and the liquid crystal layer is positioned above the color film matrix and is driven by the TFT control array. Compared with a silicon substrate, the carbon nano tubes are adopted, the small size and high resolution can be achieved, and the carbon nano tube conductors are used as wires, so that the characteristics of transparency, electric conduction and good flexibility are met; meanwhile, the CF on Array technology is used, the light of the white light LED can form colorful light when penetrating through the substrate through the light guide plate, an optical system is simpler and mature, and a high contrast ratio can be achieved by adding the polaroid.

Description

Technical Field

[0001] The present application belongs to the field of electronic devices, and in particular relates to a display device based on carbon nanotubes and a manufacturing method thereof. Background Art

[0002] LCoS (Liquid Crystal on Silicon) is a mature display technology that is widely used in high-definition television (HDTV), projectors, and augmented reality (AR) displays. Its core advantage is that it uses a silicon-based (Si-based) manufacturing process to achieve a line width of 0.38 microns, which allows the pixel size to be very small. For example, full high-definition (FHD) resolution can be achieved on a 0.26-inch panel, while 4K ultra-high-definition (UHD) resolution can be achieved on a 0.55-inch panel. This high pixel density makes LCoS perform well in displaying fine images, especially suitable for application scenarios that require high resolution.

[0003] However, despite its significant advantages in resolution and pixel density, LCoS still has some technical challenges and limitations in practical applications. First, most of the existing LCoS technology is based on a reflective design, which means that it needs to use optical components such as polarization beam splitters (PBS) and dichroic mirrors to achieve grayscale and colorization. This design not only increases the complexity of the optical system, but also leads to an increase in the size of the equipment and an increase in cost. Secondly, since LCoS relies on a reflective optical path, its optical system usually requires multiple lenses and reflectors to adjust the optical path, further increasing the complexity of the system and the difficulty of assembly. In addition, LCoS also has certain limitations in contrast. Without a polarizer, its contrast is often difficult to reach a high level, which to a certain extent limits its performance in high-end display applications.

[0004] In summary, although LCoS has significant advantages in the field of high-resolution display, its complex reflective optical system, high cost and dependence on contrast are still the main technical bottlenecks that need to be overcome in practical applications. Summary of the invention

[0005] In order to address the deficiencies of the prior art, the present application provides a carbon nanotube-based display device and a manufacturing method, which can also achieve smaller size and high resolution compared to silicon-based, and use carbon nanotube conductors as wiring, meeting the characteristics of transparency, conductivity, and good flexibility.

[0006] The technical effects to be achieved by this application are achieved through the following solutions: According to a first aspect of the present application, a carbon nanotube-based display device is provided, which comprises, from bottom to top, an LED backlight, an array substrate, and a liquid crystal layer, wherein: The LED backlight provides a white light source; The array substrate includes a TFT control array made of carbon nanotube material and a color film matrix covering the TFT control array; The liquid crystal layer is located above the color film matrix and is driven by the TFT control array.

[0007] Preferably, a light-shielding metal layer is provided between the LED backlight and the array substrate, and the light-shielding metal layer is used to shield TFT devices in the TFT control array.

[0008] Preferably, the TFT devices in the TFT control array all adopt a top gate structure, the source and drain electrodes in the TFT devices are directly connected to the semiconductor layer of carbon nanotube material, and the pixel electrodes are connected to the conductor layer through vias.

[0009] Preferably, the conductor layer made of carbon nanotube material is patterned to increase the outgoing light.

[0010] Preferably, a lower polarizer is disposed at the bottom layer of the array substrate, an upper polarizer is disposed at the top layer of the liquid crystal layer, and a lens is disposed above the upper polarizer.

[0011] Preferably, the liquid crystal layer includes, from bottom to top, a first orientation layer, liquid crystal, a second orientation layer, a cover glass and the upper polarizer, wherein the bottom of the cover glass is coated with an ITO layer, and the ITO layer is used as a common electrode to apply a COM voltage.

[0012] Preferably, the pixel electrode is driven by positive and negative voltages.

[0013] According to a second aspect of the present application, a method for manufacturing the above-mentioned carbon nanotube-based display device is provided, comprising the following steps: Step 1: forming a buffer layer on a glass substrate, and depositing, photolithography, and etching on the buffer layer to form a light-shielding metal layer; Step 2: depositing a SiOx insulating layer on the light-shielding metal layer, then pulling carbon tubes by a solution method, and photolithography and etching to form a conductor layer of carbon nanotube material, and photolithography and etching to form a source and drain pattern on the conductor layer; Step 3: pulling carbon nanotubes through the purified solution, photolithography and etching to form a carbon nanotube semiconductor layer, and deposition to form a gate dielectric layer; Step 4: After making the gate conductor layer with carbon nanotubes, an inorganic passivation layer is deposited; Step 5: Apply a color filter layer and photolithography to form a color filter matrix; Step 6: coating an organic planar layer on the color film matrix and photolithography to form organic holes, inorganic holes and gate dielectric holes, and connecting the pixel electrode to the source and drain; Step 7: Photolithography forms PS supports on the array substrate, and align and bond the ITO glass coated with frame sealant and orientation layer to the lower substrate. Step 8: After cutting, pouring liquid crystal and packaging into boxes, paste the upper and lower polarizers, assemble the LED backlight and lens, and complete the production of the display device.

[0014] Preferably, the gate dielectric layer is Al2O3, SiO x or HfO x One of them.

[0015] Preferably, the inorganic passivation layer is Al2O3 or SiO x One of a kind.

[0016] According to an embodiment of the present application, the beneficial effect of using the present carbon nanotube-based display device is that the diameter of the carbon nanotube can be made into the nm level or even smaller, and the length can be made into 0.1um. Compared with the silicon-based display, it can also achieve a smaller size and high resolution, and the carbon nanotube conductor is used as the wiring, which meets the characteristics of transparency, conductivity and good flexibility. At the same time, CF on Array (COA) technology is used to make the color film on the TFT array substrate (array substrate). When the white LED light passes through the light guide plate and the substrate, it can form colored light. After passing through the LC liquid crystal layer and modulation, the rotation of the LC can be controlled by the pixel driving circuit to achieve bright and dark states. The optical system is simpler and more mature, and adding a polarizer can achieve a higher contrast. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the existing technical solutions, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 This is a schematic structural diagram of a carbon nanotube-based display device in an embodiment of the present application; Figure 2 This is a flow chart of a method for producing a carbon nanotube-based display device in one embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0020] like Figure 1 As shown, a carbon nanotube-based display device in an embodiment of the present application includes, from bottom to top, an LED backlight, an array substrate, and a liquid crystal layer, wherein: LED backlight, using a white light LED plus a light guide plate structure to provide white light source; An array substrate, comprising a TFT control array made of carbon nanotube material and a color film matrix covering the TFT control array; The liquid crystal layer, located above the color film matrix, is driven by the TFT control array.

[0021] The beneficial effect of the display device based on carbon nanotubes is that the diameter of the carbon nanotubes can be made into the nm level or even smaller, and the length can be made into 0.1um. Compared with silicon-based, it can also achieve smaller size and high resolution, and the carbon nanotube conductor is used as the wiring, which meets the characteristics of transparency, conductivity and good flexibility. In one embodiment of the present application, a shading metal layer is provided between the LED backlight and the array substrate. The shading metal layer is used to shield the TFT devices in the TFT control array to prevent the LED light from directly irradiating the carbon nanotube (CNT) semiconductor tubes, thereby preventing the carbon nanotubes from being damaged by heating due to irradiation, helping to improve the normal operation of the carbon nanotube circuit at normal temperature and avoiding distortion or instability of the display signal.

[0022] It can also prevent the carbon nanotubes from being oxidized or undergoing other photochemical reactions under light, which would lead to a decrease in light transmittance, and increase the service life of the carbon nanotubes, thereby improving the long-term reliability of the display device.

[0023] The light-shielding metal layer uses a thinner metal layer, such as Mo, Ti, Al, etc. The pattern of the light-shielding metal layer is consistent with the transistor, which can block the light of the LED backlight and avoid direct irradiation of the semiconductor active layer.

[0024] In order to increase the aperture ratio of the pixel and increase the emitted light, a transparent CNT conductor layer is used for patterning.

[0025] In one embodiment of the present application, the TFT devices in the TFT control array all adopt a top gate structure, the source and drain electrodes in the TFT devices are directly connected to the semiconductor layer of the carbon nanotube material, and the pixel electrode is connected to the conductor layer through vias in the gate dielectric, passivation layer and organic planar layer, and thus connected to the drain of the transistor, which is placed above the COA (CF on Array).

[0026] In one embodiment of the present application, a lower polarizer is disposed at the bottom layer of the array substrate, an upper polarizer is disposed at the top layer of the liquid crystal layer, a lens is disposed above the upper polarizer, and the polarization directions of the upper and lower polarizers are perpendicular, and the vertical arrangement enables the liquid crystal molecules to control the polarization state of the light through the electric field when the light passes through the liquid crystal layer, thereby realizing the display of the image. When the liquid crystal molecules do not change the polarization direction of the light, the light will be blocked by the upper and lower polarizers, and the screen will be displayed in a dark state; when the liquid crystal molecules change the polarization direction, the light passes through the upper and lower polarizers, and the screen will be displayed in a bright state.

[0027] The liquid crystal layer includes the first orientation layer, liquid crystal, the second orientation layer, the cover glass and the upper polarizer from bottom to top. The bottom of the cover glass is coated with an ITO layer, which is used as a common electrode to apply the COM voltage. The first orientation layer and the second orientation layer are used to control the initial arrangement direction of the liquid crystal molecules, thereby ensuring that the liquid crystal layer (LC layer) can modulate light according to the design requirements.

[0028] By controlling the voltage on the pixel electrode and controlling the rotation of the liquid crystal, the emitted light is modulated. When the pixel electrode voltage is the COM voltage, the voltage applied to both ends of the liquid crystal is 0, the liquid crystal does not rotate, the polarization direction of the light is orthogonal to the upper polarizer, and it cannot be emitted, presenting a black state. When the pixel electrode voltage is high or low, the bias voltage applied to both ends of the liquid crystal is not 0, the liquid crystal rotates, and the polarization direction of the light changes and is modulated and emitted.

[0029] In order to prevent the aging of the liquid crystal material, the pixel electrode is driven by positive and reverse voltages, that is, the voltage signal on the pixel electrode is periodically switched between positive polarity (+V) and negative polarity (-V), ensuring that the direction of the electric field applied to the liquid crystal layer is reversed periodically, avoiding the long-term application of an electric field in a single direction that may cause aging of the liquid crystal material and image retention.

[0030] The above-mentioned display device based on carbon nanotubes uses transmissive liquid crystal and upper and lower polarizers to modulate light, replacing PBS and reflective liquid crystal, reducing the complexity of the system and the difficulty of assembly, which helps to reduce the cost of the display device; using a backplane made of carbon nanotube material, it has high precision and can achieve high resolution in a small size, and uses carbon nanotube semiconductors and conductors at the same time, such as a stacked CNT backplane, a CNT semiconductor of the TFT active layer and the conductive channel, and a carbon nanotube semiconductor for the source, drain and gate of the TFT, which can increase the transmittance; using a COA+WLED (white light emitting diode) structure, replacing the R, G, B three-color light source or a spectroscope, greatly reduces the complexity of the structure, which helps to reduce product costs and installation difficulties. This display device can be used in projection, AR, HDTV and other fields.

[0031] like Figure 2 As shown, the method for manufacturing the above-mentioned carbon nanotube-based display device comprises the following steps: Step 1: forming a buffer layer on a glass substrate, and depositing, photolithography, and etching on the buffer layer to form a light-shielding metal layer; Step 2: Deposit a SiOx insulating layer on the light-shielding metal layer, then pull the carbon nanotubes through a solution method (different from the solution used to pull the carbon nanotube semiconductor), and form a conductor layer of carbon nanotube material by photolithography and etching, and form a source and drain pattern on the conductor layer by photolithography and etching; Step 3: Draw carbon nanotubes from the purified solution, photolithography and etching to form a carbon nanotube semiconductor layer, and deposit Al2O3, SiO x or HfO x as a gate dielectric layer; Step 4: Use carbon nanotubes to make a gate conductor layer, photolithography and etching to form a pattern, and deposit Al2O3 or SiO x As an inorganic passivation layer; Step 5: Apply R, G, and B color filter layers and photolithography to form a color filter matrix; Step 6: coating an organic planar layer on the color film matrix and photolithography to form organic holes, inorganic holes and gate dielectric holes, and connecting the pixel electrode to the transistor drain; Step 7: Photolithography forms a PS support on the array substrate, align and bond the ITO glass coated with the sealant and the orientation layer to the lower substrate (array substrate). There are gold balls in the support spacer, which are used to connect the ITO common electrodes of the upper and lower substrates. Step 8: Cut the above substrate into the required size, inject liquid crystal and package it into a box, paste the polarizer on the liquid crystal box, paste the polarizer under the array substrate, assemble the backlight white light LED and light guide plate, assemble the lens, and complete the production of the display device.

[0032] The patterning process in the above steps refers to different pattern designs of source and drain patterns, gate patterns and top gate structures according to the shape of the TFT, such as long straight strips, U-shaped, forked fingers and the like.

[0033] This carbon nanotube-based display device uses CF on Array (COA) technology to make a color film on a TFT array substrate (array substrate). When the white LED light passes through the substrate through the light guide plate, it can form colored light. After modulation through the LC liquid crystal layer, the rotation of the LC can be controlled by the pixel driving circuit to achieve bright and dark states.

[0034] This display device simplifies the optical system, does not require PBS and reflective metal layers, has a higher contrast, uses color film spatial light mixing, does not require a three-color light source or a beam splitter, reduces the size of the device, and has a simpler and more mature optical system. Adding a polarizer can achieve a higher contrast.

[0035] It should be noted that the above detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present application belongs.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0038] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0039] For ease of description, spatially relative terms, such as "above", "above", "on the upper surface of", "above", etc., may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatially relative descriptions used herein are interpreted accordingly.

[0040] In the above detailed description, reference is made to the accompanying drawings, which form a part of this document. In the accompanying drawings, similar symbols typically identify similar components unless the context indicates otherwise. The illustrated embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A display device based on carbon nanotubes, characterized in that: From bottom to top, it includes LED backlight, array substrate and liquid crystal layer, among which: The LED backlight is an edge-lit LED that provides a white light source; The array substrate includes a TFT control array made of carbon nanotube material and a color film matrix covering the TFT control array; The liquid crystal layer is located above the color film matrix and is driven by the TFT control array.

2. The carbon nanotube-based display device according to claim 1, characterized in that: A light-shielding metal layer is arranged between the LED backlight and the array substrate, and the light-shielding metal layer is used to shield the TFT devices in the TFT control array.

3. The carbon nanotube-based display device according to claim 1, characterized in that: The TFT devices in the TFT control array all adopt a top gate structure, the source and drain electrodes in the TFT devices are directly connected to the semiconductor layer of carbon nanotube material, and the pixel electrodes are connected to the conductor layer through vias.

4. The carbon nanotube-based display device according to claim 3, characterized in that: The semiconductor layer made of carbon nanotube material is patterned to increase the outgoing light.

5. The carbon nanotube-based display device according to claim 3, characterized in that: The bottom layer of the array substrate is provided with a lower polarizer, the top layer of the liquid crystal layer is provided with an upper polarizer, and a lens is provided above the upper polarizer.

6. The carbon nanotube-based display device according to claim 5, characterized in that: The liquid crystal layer includes, from bottom to top, a first orientation layer, liquid crystal, a second orientation layer, a cover glass and the upper polarizer, wherein the bottom of the cover glass is coated with an ITO layer, and the ITO layer is used as a common electrode to apply a COM voltage.

7. The carbon nanotube-based display device according to claim 6, characterized in that: The pixel electrode is driven by positive and negative voltages.

8. A method for manufacturing a display device based on carbon nanotubes according to any one of claims 1 to 7, characterized in that: The steps include: Step 1: forming a buffer layer on a glass substrate, and depositing, photolithography, and etching on the buffer layer to form a light-shielding metal layer; Step 2: depositing a SiOx insulating layer on the light-shielding metal layer, then pulling carbon tubes by a solution method, and photolithography and etching to form a conductor layer of carbon nanotube material, and photolithography and etching to form a source and drain pattern on the conductor layer; Step 3: pulling carbon nanotubes through the purified solution, photolithography and etching to form a carbon nanotube semiconductor layer, and deposition to form a gate dielectric layer; Step 4: After making the gate conductor layer with carbon nanotubes, an inorganic passivation layer is deposited; Step 5: Apply a color filter layer and photolithography to form a color filter matrix; Step 6: coating an organic planar layer on the color film matrix and photolithography to form organic holes, inorganic holes and gate dielectric holes, and connecting the pixel electrode to the source and drain; Step 7: Photolithography forms a PS support on the array substrate, and aligns and bonds the ITO glass coated with the sealant and the alignment layer to the lower substrate; Step 8: After cutting, pouring liquid crystal and packaging into a box, paste the upper and lower polarizers, assemble the LED backlight and lens, and complete the production of the display device.

9. The method for manufacturing a display device based on carbon nanotubes according to claim 8, characterized in that: The gate dielectric layer is Al2O3, SiO x or HfO x One of them.

10. The method for manufacturing a display device based on carbon nanotubes according to claim 8, characterized in that: Inorganic passivation layer is Al2O3 or SiO x One of a kind.

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