Transparent monochromatic display device based on low-temperature polycrystalline silicon driving substrate

Abstract

The invention relates to a transparent monochromatic display device based on a low-temperature polycrystalline silicon driving substrate, and belongs to the technical field of transparent display. According to the display device, a thin film transistor with an active layer made of low-temperature polycrystalline silicon is arranged on a transparent back plate, and a monochromatic light-emitting unit matched with the thin film transistor is controlled through the thin film transistor, so that on one hand, the monochromatic light-emitting unit is more densely arranged by means of the characteristic that the low-temperature polycrystalline silicon supports higher pixel density, and the display density is improved; on the other hand, the light-emitting unit is directly driven by the thin film transistor by means of the characteristic that low-temperature polycrystalline silicon has higher electron mobility, structures such as a pixel electrode and a common electrode are not needed any more, the production difficulty and cost are remarkably reduced, and on the other hand, the light transmittance is improved by means of the transparency characteristic of the low-temperature polycrystalline silicon. It can be known that the defect that existing monochromatic display pixels are low in density is overcome, the production cost is reduced, the transparency is improved, and high-light-transmittance and high-density display under low cost is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of transparent display, and particularly to a transparent monochromatic display device based on a low-temperature polysilicon driving substrate. Background Art

[0002] In current retail and supermarket scenarios, information display generally relies on static media such as handwritten labels and paper posters. Window advertisements are also mostly limited to one-way transmission of opaque electronic screens, with disadvantages such as low update efficiency, weak interactivity, and insufficient space utilization. Transparent display devices, with characteristics such as high light transmittance, real-time switching of dynamic information, and two-way visibility, can enable retail storefronts to achieve virtual-real fusion of product displays and supermarket shelf labels to achieve transparent prompts, resulting in an immersive consumption experience. Therefore, they are increasingly favored by manufacturers and users and are developing rapidly.

[0003] However, the current cost of color light-transmitting screens is relatively high, and it is difficult to achieve a high light transmittance. At the same time, it is also very difficult to increase the pixel density. Although transparent monochromatic display screens can achieve a relatively low cost, due to material limitations, their pixel density is not high. On the premise that the lack of color display significantly reduces the richness of information display, this low pixel density further affects the richness of information display, thereby affecting the immersion level during the interaction process and reducing the user experience.

[0004] That is to say, current transparent display screens cannot balance low cost and high information display richness, and there is a problem that high light transmittance and high display density cannot be achieved at low cost. Summary of the Invention

[0005] In view of this, the present invention provides a transparent monochromatic display device based on a low-temperature polysilicon driving substrate to solve the technical problem that current transparent display devices cannot achieve high light transmittance and high display density at low cost.

[0006] A transparent monochromatic display device based on a low-temperature polysilicon driving substrate provided by the present invention includes a low-temperature polysilicon driving substrate, a first preset number of thin film transistors with an active layer of low-temperature polysilicon, the first preset number of monochromatic light-emitting units, a second preset number of scan lines, a third preset number of data lines, and the third preset number of ground lines; The low-temperature polysilicon driving substrate is a transparent substrate. The set number of thin film transistors are disposed on the low-temperature polysilicon driving substrate. The gates of the thin film transistors in the same row are connected to the same scan line, the sources of the thin film transistors in the same column are connected to the same data line, the positive electrode of each monochromatic light-emitting unit is connected to one thin film transistor respectively, and the negative electrodes of the monochromatic light-emitting units in the same column or the same row are connected to the same ground line.

[0007] Optionally, each of the thin film transistors is adjacent to and non-overlapping with its corresponding monochromatic light emitting unit.

[0008] Optionally, the monochromatic light emitting unit is a sub-millimeter light emitting diode or a micro-meter light emitting diode.

[0009] Optionally, the line widths of the scanning line, the data line, and the ground line are all not less than 50 μm and not greater than 200 μm.

[0010] Optionally, the materials of the gate, source, and drain of the thin film transistor are transparent conductive oxide or nano silver wire.

[0011] Optionally, the contact area of the source and the drain uses metal, and other areas use indium tin oxide; The gate forms a micron-level grid with metal traces, and indium tin oxide is filled in the micron-level grid.

[0012] Optionally, a transparent graphene heat dissipation film is provided on the back surface of the low-temperature polycrystalline silicon driving substrate.

[0013] Optionally, the gap between the monochromatic light emitting units is filled with an optical adhesive having a thermal conductivity > 1.5 W / mK.

[0014] The beneficial effects of the present invention compared with the prior art are as follows: In the present invention, a thin film transistor with a low-temperature polycrystalline silicon active layer is constructed on a transparent backplane. Through the characteristic that the AND gate control logic can be formed between the gate and the source of the constructed thin film transistor, it is combined with the monochromatic light emitting unit to realize the independent display control of a single pixel. On the one hand, by virtue of the technical characteristics of low-temperature polycrystalline silicon that supports higher resolution and pixel density, the layout density of the monochromatic light emitting units is significantly improved. On the other hand, by virtue of the performance characteristics of low-temperature polycrystalline silicon with higher electron mobility, the light emitting unit is directly driven by the thin film transistor, without the need to arrange pixel electrodes, common electrodes and other structures for pixel control on the basis of the thin film transistor as in the conventional display structure, which significantly reduces the production difficulty and cost of the display device. On the other hand, the light transmittance is improved by virtue of the transparent characteristics of low-temperature polycrystalline silicon. Finally, the transparent monochromatic display device based on the low-temperature polycrystalline silicon driving substrate of the present invention further reduces the cost by successfully abandoning the conventional pixel electrodes, common electrodes and other structures while having a lower cost in monochromatic display compared with color display, and at the same time makes up for the defect of the low pixel density of the existing monochromatic display, realizing high light transmittance and high display density at low cost. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] Figure 1 It is a monochromatic display schematic diagram of a transparent monochromatic display device based on a low-temperature polysilicon driving substrate provided in the first embodiment of the present invention. Specific embodiments

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0018] It should be understood that the present invention can be implemented in different forms and should not be construed as limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout the drawings.

[0019] It should be understood that when an element or layer is referred to as "on", "adjacent to", "connected to", or "coupled to" another element or layer, it can be directly on, adjacent to, connected, or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as "directly on", "directly adjacent to", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part.

[0020] Spatial relationship terms such as "under", "below", "lower", "beneath", "above", "upper", etc. may be used herein for convenience of description to describe the relationship of one element or feature shown in the figures with other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatial relationship terms are also intended to include different orientations of the device in use and operation. For example, if the device in the figures is flipped, then elements or features described as "below other elements" or "beneath them" or "under them" will be oriented "above" the other elements or features. Thus, the exemplary terms "below" and "under" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are to be interpreted accordingly.

[0021] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, specify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. As used herein, the term "and / or" includes any and all combinations of the related listed items.

[0022] To fully understand the present invention, detailed structures and steps will be set forth in the following description to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may have other embodiments.

[0023] As Figure 1 shown, it is a monochromatic display schematic diagram of a transparent monochromatic display device based on a low-temperature polysilicon driving substrate provided by an embodiment of the present invention.

[0024] In this embodiment, the transparent monochromatic display device based on the low-temperature polysilicon driving substrate uses a transparent substrate, which may specifically be a glass substrate or a transparent polyimide (PI) film. An active layer of low-temperature polysilicon (LTPS) thin-film transistor layer is formed on the transparent substrate, so that a plurality of thin-film transistors are arranged on the low-temperature polysilicon driving substrate to form a substrate driven by low-temperature polysilicon.

[0025] Preferably, in this embodiment, the thin-film transistors are arranged in a row-column form as Figure 1 shown on the low-temperature polysilicon driving substrate. Assuming the number of rows is m and the number of columns is n, there are a total of m×n thin-film transistors.

[0026] The function of the thin-film transistor in this embodiment is to control the conduction of the monochromatic light-emitting unit. Therefore, corresponding to the thin-film transistor, the number of monochromatic light-emitting units is set to be the same as that of the thin-film transistors, that is, also m×n. To minimize the wiring length and thus improve the light transmittance, the monochromatic light-emitting unit is arranged adjacent to its corresponding thin-film transistor. However, to avoid the thin-film transistor blocking the monochromatic light-emitting unit and affecting the display effect, it is also necessary to ensure that the thin-film transistor does not overlap with its corresponding monochromatic light-emitting unit.

[0027] Among them, for the independent control of each monochromatic light-emitting unit, this embodiment utilizes the structural characteristic that the gate and source of the thin-film transistor can form an "AND gate" to control whether its drain outputs current, so as to achieve the independent control of each monochromatic light-emitting unit.

[0028] Specifically, in this embodiment, first, the gates of the thin-film transistors in the same row are all connected to the same scanning line, then the sources of the thin-film transistors in the same column are all connected to the same data line, then the drain of each thin-film transistor is connected to the positive electrode of the monochromatic light-emitting unit corresponding to this thin-film transistor, and the negative electrodes of the monochromatic light-emitting units in the same column are all connected to the same ground line.

[0029] After such setting, by applying power to the i-th row scanning line and the j-th column data line, the monochromatic light-emitting unit at the same position can be powered through the drain of the thin-film transistor at the position of the i-th row and j-th column. On the contrary, if at least one of the i-th row scanning line or the j-th column data line is not powered, there will be no current output at the drain of the thin-film transistor at the position of the i-th row and j-th column, thus unable to power the monochromatic light-emitting unit at the same position. In this way, the independent control of the monochromatic light-emitting unit at this position is achieved.

[0030] Corresponding to the structure where the thin-film transistors and the monochromatic light-emitting units are arranged in an m×n row-column form on the low-temperature polysilicon driving substrate, at least m scanning lines are required for the horizontally arranged scanning lines, and at least n data lines and ground lines are required for the vertically arranged data lines and ground lines. And in this embodiment, each thin-film transistor and its corresponding monochromatic light-emitting unit are arranged as close as possible without overlapping. Therefore, it can be considered that each thin-film transistor and its corresponding monochromatic light-emitting unit form an overall controllable light-emitting module. So in this embodiment Figure 1 At the upper left corner of each pixel region, the thin-film transistor and its corresponding monochromatic light-emitting unit are represented together in a single small rectangular region.

[0031] It is easy to understand that each thin-film transistor and its corresponding monochromatic light-emitting unit are not only adjacent to each other. The monochromatic light-emitting unit can also be arranged in the light-transmitting region of each pixel region as shown in Figure 1 That is, the region outside the above-mentioned single small rectangular region does not affect the controllable display function of the display device.

[0032] Meanwhile, in order to minimize the light blocking of the light-emitting unit as much as possible and thus improve the transparency, it is preferred that the monochromatic light-emitting unit is a sub-millimeter light-emitting diode or a micrometer light-emitting diode. Also, in order to balance transparency and conductivity, the line widths of the scanning line, the data line, and the ground line are all set to be not less than 50 μm and not greater than 200 μm.

[0033] Although Figure 1 the thin-film transistor and its corresponding monochromatic light-emitting unit are represented by a black rectangular area, in order to improve the light transmittance, the thin-film transistor is set to be as transparent as possible. Specifically: In a preferred embodiment, in order to improve the light transmittance of the thin-film transistor as much as possible, the materials of the gate, source, and drain of the thin-film transistor are set to be transparent conductive oxides or nanosilver wires, where the transparent conductive oxides include but are not limited to ITO (indium tin oxide).

[0034] In this way, on the basis of ensuring the function realization of the thin-film transistor, the overall light transmittance of the thin-film transistor can be improved.

[0035] Furthermore, in another preferred embodiment, in order to balance high transparency and good conductivity, the contact regions of the source and drain of the thin-film transistor are made of metal to ensure low contact resistance, and other regions are made of indium tin oxide; and the gate is formed in the form of a micrometer-scale grid of metal traces and filled with ITO (indium tin oxide) within the micrometer-scale grid.

[0036] In this way, high transparency and good conductivity can be balanced, enabling the display device to achieve better display performance and light transmittance performance.

[0037] Also, in order to improve the stability and heat dissipation of the display device, a transparent graphene heat dissipation film can also be optionally integrated on the back of the substrate. Preferably, the thermal conductivity of the transparent graphene heat dissipation film > 1500 W / m•K; and a high thermal conductivity optical adhesive with a thermal conductivity > 1.5 W / mK is used to fill the gaps between the monochromatic light-emitting units.

[0038] In the embodiment of the present invention, a thin-film transistor with a low-temperature polysilicon active layer is constructed on a transparent backplane. By virtue of the AND gate control logic characteristic formed by the gate and source of the constructed thin-film transistor, it is combined with a monochromatic light-emitting unit to achieve independent display control of a single pixel. On the one hand, relying on the technical characteristics of low-temperature polysilicon to support higher resolution and pixel density, the layout density of the monochromatic light-emitting unit is significantly improved. On the other hand, due to the performance characteristic of low-temperature polysilicon having a higher electron mobility, the light-emitting unit is directly driven by the thin-film transistor, without the need to arrange structures such as pixel electrodes and common electrodes for pixel control on the basis of the thin-film transistor as in a conventional display structure, significantly reducing the production difficulty and cost of the display device. On the further hand, the light transmittance is increased by virtue of the transparent characteristic of low-temperature polysilicon. Finally, the transparent monochromatic display device based on a low-temperature polysilicon driving substrate of the present invention, while the cost of monochromatic display is lower than that of color display, further reduces the cost by successfully abandoning conventional structures such as pixel electrodes and common electrodes, and at the same time makes up for the defect of the low pixel density of the existing monochromatic display, achieving high light transmittance and high display density at low cost.

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and shall all be included in the protection scope of the present invention.

Claims

1. A transparent monochromatic display device based on a low-temperature polysilicon driving substrate, characterized in that, It includes a low-temperature polysilicon driving substrate, a first preset number of thin-film transistors with low-temperature polysilicon as the active layer, the first preset number of monochromatic light-emitting units, a second preset number of scan lines, a third preset number of data lines, and the third preset number of ground lines; The low-temperature polysilicon driving substrate is a transparent substrate. The set number of thin-film transistors are arranged on the low-temperature polysilicon driving substrate. The gates of the thin-film transistors in the same row are connected to the same scan line, the sources of the thin-film transistors in the same column are connected to the same data line, the anode of each monochromatic light-emitting unit is connected to each respective thin-film transistor, and the cathodes of the monochromatic light-emitting units in the same column or the same row are connected to the same ground line.

2. The transparent monochromatic display device based on a low-temperature polysilicon driving substrate according to claim 1, wherein Each thin-film transistor is adjacent to and non-overlapping with its corresponding monochromatic light-emitting unit.

3. The transparent monochromatic display device based on a low-temperature polysilicon driving substrate according to claim 1, characterized in that, The monochromatic light-emitting unit is a sub-millimeter light-emitting diode or a micro-meter light-emitting diode.

4. The transparent monochromatic display device based on a low-temperature polysilicon driving substrate according to claim 1, wherein The line widths of the scan line, the data line, and the ground line are all not less than 50um and not greater than 200um.

5. The transparent monochromatic display device based on a low-temperature polysilicon driving substrate according to any one of claims 1 to 4, characterized in that, The materials of the gate, source, and drain of the thin-film transistor are transparent conductive oxide or nano silver wire.

6. The transparent monochromatic display device based on a low-temperature polysilicon driving substrate according to any one of claims 1 to 4, characterized in that, The contact area of the source and the drain uses metal, and other areas use indium tin oxide; The gate forms a micron-level grid with metal traces, and indium tin oxide is filled in the micron-level grid.

7. The transparent monochromatic display device based on a low-temperature polysilicon driving substrate according to claim 1, characterized in that, A transparent graphene heat dissipation film is provided on the back of the low-temperature polysilicon driving substrate.

8. The transparent monochromatic display device based on a low-temperature polysilicon driving substrate according to claim 1, wherein The gap between the monochromatic light-emitting units is filled with an optical adhesive with a thermal conductivity > 1.5W / mK.

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