Controllable pixelated color display device based on indium tin oxide

Abstract

The invention discloses a controllable pixelated color display device based on indium tin oxide (ITO), which realizes full-color-gamut accurate color display in a visible light region through double-variable coordinated regulation and control of the thickness of an indium tin oxide (ITO) film and a heating temperature, and does not need additional functional materials. The display unit comprises a substrate, a reflecting layer and an ITO functional layer from bottom to top, RGB color gamut coverage is achieved through thickness regulation and control, and single-thickness multi-color gradient can be achieved through heating at the temperature of 150-350 DEG C. The pixelated device is additionally provided with a cross electrode connection layer and an insulation isolation layer, an M * N matrix array is adopted, pixel-level addressing is achieved through passive matrix driving, and dynamic color switching is achieved through accurate heating through electric heating. The device is simplified in structure and low in cost, the technology is compatible with an existing semiconductor process, large-scale mass production is adapted, and the device can be widely applied to the fields of intelligent terminals, AR display, vehicle-mounted display and wearable equipment.

Description

Technical Field

[0001] This invention relates to the field of color display device technology, and more specifically to a controllable pixelated color display device based on indium tin oxide. Background Technology

[0002] Display technology, as a core carrier of human-computer interaction, has been widely applied in fields such as smart terminals, automotive displays, and wearable devices. Among them, reflective color display, due to its lack of backlighting and low energy consumption, represents an important direction for portable and transparent displays. Current mainstream solutions include reflective LCDs, electrochromic reflective displays, cholesteric liquid crystal reflective displays, and pigment-dispersed reflective displays, but they suffer from several technical drawbacks: First, existing technologies often rely on multi-material composite structures, such as multi-layered film structures of electrochromic electrodes, color-changing layers, and electrolyte layers, resulting in complex structures, poor interface compatibility, and insufficient device stability. Second, there is a lack of pixel-level independent color control methods; for example, cholesteric liquid crystals are difficult to implement in full-color arrays, and electrochromic partitioned driving is prone to crosstalk. Third, traditional control methods, such as overall voltage driving and high-temperature annealing, are difficult to adapt to large-scale fabrication. Therefore, developing a display device with a simplified structure, low cost, pixel-level precise color control, and adaptability to large-scale fabrication has become an urgent technical problem to be solved in the field of display technology.

[0003] In existing display technologies, indium tin oxide (ITO) films are often used as transparent electrode materials due to their excellent light transmittance and conductivity, and are typically combined with functional materials such as quantum dots and organic light-emitting layers to achieve color display. However, current technologies have not fully explored the color modulation potential of ITO films themselves. Summary of the Invention

[0004] To overcome the shortcomings of the existing technology, this invention provides a controllable pixelated color display device based on indium tin oxide (ITO). This invention uses a single ITO thin film as the functional layer material and achieves accurate full-color gamut display in the visible light region by coordinating the thickness and heating temperature of the ITO thin film. The device structure is simpler, the control is easier, and the cost is lower.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A controllable pixelated color display device based on ITO includes: a substrate and a cross electrode line layer, an insulating isolation layer 202, and an ITO pixel display array disposed on the substrate. The ITO pixel display array consists of multiple independent ITO color display units arranged in an M×N matrix array (M and N are positive integers ≥10). The cross electrode circuit layer includes a lower electrode circuit layer 201 and an upper electrode circuit layer 205. The columns of the M×N matrix correspond to the lower electrode circuit layer 201, and the rows correspond to the upper electrode circuit layer 205. The upper end of the reflective layer 102 of the ITO color display unit is connected to the upper electrode connection layer 205, and the lower end is connected to the lower electrode connection layer 201. An external circuit is established outside the cross electrode circuit layer. The external circuit adopts a passive matrix drive architecture. The lower electrode circuit layer 201 distributed by columns and the upper electrode circuit layer 205 distributed by rows form an orthogonal cross matrix structure. Each cross node corresponds one-to-one with an ITO color display unit. Precise addressing control of a single ITO color display unit is achieved by selectively energizing the lower electrode circuit layer 201 corresponding to the column and the upper electrode circuit layer 205 corresponding to the row. Selective energizing of one or more ITO color display units is achieved through the timing control of the external control unit. An insulating isolation layer 202 is located above the lower electrode connection layer 201. The insulating isolation layer 202 is used to prevent short circuits between the lower electrode circuit layer 201 and the upper electrode circuit layer 205.

[0006] The electrode width of the lower electrode circuit layer 201 and the upper electrode circuit layer 205 is controlled to be 5-40μm, and the electrode spacing is 80-100μm to avoid circuit damage caused by tip discharge. The passive matrix drive architecture includes a row driver chip, a column driver chip, and an external control unit. The row driver chip outputs a strobe signal, and the column driver chip outputs a drive signal.

[0007] Joule heating of the target ITO color display unit is performed using the cross electrodes of the cross electrode circuit layer. The power supply (preferably 1-3W, 6-10W for 200μm×200μm pixels) and power supply time are precisely controlled by an external control unit, so that the temperature of the ITO functional layer 103 of the target unit reaches the preset temperature precisely. The crystallization area and grain size of the ITO functional layer 103 are controlled by the heating process, thereby achieving precise color control. The power output ranges from 1 to 10W, adaptable to pixel size (50μm×50μm pixel); the power-on time is 10-60ms; and the preset temperature is 150-350℃.

[0008] Meanwhile, in the above-mentioned fabrication of ITO controllable pixelated color display devices, photolithography mask partition deposition is used to achieve differentiated thickness, and partitioned temperature control heating is combined to achieve precise color regulation; and passive matrix driving is adapted to achieve dynamic color display control of the pixel array.

[0009] The ITO color display unit consists of a substrate 101, a reflective layer 102, and an ITO functional layer 103, arranged from bottom to top along the Z-axis. The substrate 101, the reflective layer 102, and the ITO functional layer 103 have the same width; The length of the ITO functional layer 103 is shorter than the lengths of the substrate 101 and the reflective layer 102; The size range of the ITO functional layer 103 is 50-200μm×50-200μm; the substrate 101 and the reflective layer 102 have the same length, ranging from 100-300μm. The material selection, structural parameters, and functional implementation logic of each layer are as follows, ensuring that each layer works together to guarantee the stability and accuracy of color display: The reflective layer 102 is used to provide specular reflection, enhance the intensity of reflected light from the ITO functional layer, and improve color display saturation; The ITO functional layer 103 is used to regulate the reflectivity of the device, and the display color can be regulated by adjusting the thickness of the ITO functional layer 103.

[0010] The reflective layer 102 is made of a transparent conductive material with a reflectivity of ≥90%, preferably Pt, Ag, or Al, and has a thickness of ≥50 nm.

[0011] The thickness of the ITO functional layer 103 is a key parameter that determines the reflectance spectral characteristics. The thickness can be adjusted by precisely controlling the deposition rate and time, with a thickness range of 5 nm ≤ thickness ≤ 100 nm. The mass ratio of conductive indium oxide to tin oxide in the ITO functional layer 103 is 9:1, which ensures that it has good crystallinity and optical control capabilities.

[0012] Specifically, the thickness of the ITO functional layer 103 has a clear correspondence with the reflectance spectrum and display colors: When the thickness is 5-15nm: the ITO color display unit displays a bright red; When the thickness is 20-40nm: the ITO color display unit displays a light yellow or neutral color; When the thickness is 40-70nm: the ITO color display unit displays purple; When the thickness is 80-100nm: the ITO color display unit displays blue; Furthermore, the aforementioned ITO color display unit undergoes programmed heating to achieve secondary precise color control and stability optimization. The specific heating process parameters are as follows: heating temperature range is 150-350℃ (preferably 200-350℃), and holding time is 0-10min (the greater the thickness, the longer the holding time, such as 8-10min for a 100nm thick ITO layer). The control mechanism of the heat treatment is as follows: by adjusting the heating temperature and holding time, the crystallization region and grain size of the ITO layer are precisely controlled. The higher the heating temperature and the longer the holding time, the larger the crystallization region and grain size, thereby changing its dielectric constant and light reflection characteristics, causing a shift in the peak value of the reflection spectrum, and ultimately achieving a continuous multi-color gradient in an ITO layer of the same thickness. For example, an ITO layer with a thickness of 50nm is purple without heating, turns orange-red after heating to 250℃, and turns orange-pink after heating to 350℃. Precise switching of multiple colors within a single thickness is achieved through heating.

[0013] The reflective layer 102 is prepared on the substrate surface by magnetron sputtering or electron beam evaporation, and the ITO functional layer 103 is deposited on the upper surface of the reflective layer by magnetron sputtering.

[0014] The device is used in smart terminals, AR displays, automotive displays, and wearable devices.

[0015] The beneficial effects of this invention are: The controllable pixelation display device based on ITO proposed in this invention uses a single ITO as the core color layer, abandoning the complex structures of polarizers and composite color-changing layers in traditional reflective displays. The device architecture is simplified and has excellent interface compatibility. ITO material is mature and mass-produced, and the preparation process is compatible with existing semiconductor processes. No special additional steps are required, which greatly reduces material and industrialization costs, while avoiding the stability problems caused by multi-material composites.

[0016] By controlling both ITO thickness and heating temperature, the heating process can gradually adjust the crystallization area and grain size, thereby achieving continuous color gradation and full color gamut display. Combined with orthogonal addressing of cross electrode circuits, pixel-level independent color control can be achieved, supporting rapid dynamic switching and breaking through the bottlenecks of traditional reflective displays, such as narrow color control range, difficulty in pixel-level adjustment, and inability to dynamically switch.

[0017] The process employs a zoned heating method with bottom electrode energized heating, replacing traditional overall heating or excimer laser heating technology. This method offers a wide process window and low temperature uniformity, allowing for precise matching of the zoned processing requirements of pixel arrays. Furthermore, the process is compatible with existing semiconductor industrialization processes, requires no complex equipment maintenance, significantly improves the feasibility of large-scale mass production, and solves the problems of poor adaptability and high mass production difficulty of existing reflective display control processes.

[0018] This invention utilizes the changes in the optical properties of ITO thin films under different fabrication processes to achieve precise color control in the visible light region through multi-variable synergistic regulation. It also combines a partitioned heating process to construct a pixelated array, providing a new solution for further breakthroughs in display technology. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an ITO-based color display unit.

[0020] Figure 2 This is a reflectance spectrum of an ITO-based color display unit.

[0021] Figure 3 This is a comparison of the chromaticity coordinates of ITO in its deposited state and after heat treatment at different temperatures.

[0022] Figure 4 This is a planar schematic diagram of a controllable pixelation display device based on ITO. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] like Figure 4 As shown, the present invention discloses a controllable pixelated color display device based on indium tin oxide, wherein each part is a lower electrode line layer 201, an insulating isolation layer 202, an ITO color display unit reflective layer 102, a functional layer 103, and an upper electrode line layer 205. The lower electrode line layer 201 is located above the substrate, and the lower electrode line layer 201 is used to connect to the lower side of the ITO color display unit reflective layer 102. An insulating layer 202 is located above the lower electrode circuit layer 201, and the insulating layer 202 is used to prevent the lower electrode circuit layer 201 from short-circuiting with the upper electrode circuit layer 205. The ITO color display unit reflective layer 102 is located above the substrate. The length of the ITO color display unit reflective layer 102 is greater than the length of the functional layer 103. The extra area is used to connect the lower electrode circuit layer 201 and the upper electrode circuit layer 205. The ITO color display unit functional layer 103 is located above the reflective layer 102, and the size of the functional layer is 50-200μm×50-200μm; The upper electrode line layer 205 is located above the insulating isolation layer 202, and the upper electrode line layer 205 is used to connect to the upper side of the ITO color display unit reflective layer 102.

[0025] like Figure 1 The diagram shows a color display unit based on ITO. From bottom to top, the layers are: substrate 101, reflective layer 102, and functional layer 103. The reflective layer 102 has a thickness of ≥50nm and is used to provide specular reflection. The dielectric layer 103 has a thickness of 5-100nm and is used to adjust the reflectivity of the device. The substrate 101, the reflective layer 102, and the ITO functional layer 103 have the same width; The length of the ITO functional layer 103 is shorter than the lengths of the substrate 101 and the reflective layer 102; The size range of the ITO functional layer 103 is 50-200μm × 50-200μm; The substrate 101 and the reflective layer 102 have the same length, ranging from 100 to 300 μm.

[0026] Based on the aforementioned ITO color display unit, this section discloses an ITO controllable pixelated display device. The core functionality involves selective control of individual display units through the addressing function of cross-electrode lines, coupled with a quantitative and precise heating method using electrical heating to achieve dynamic color regulation. Its structure adds a cross-electrode line layer and an insulating layer to a conventional display unit. The coordinated design of these structures ensures the accuracy of pixel-level control and the long-term stability of the device. Specific structural components, design parameters, and control logic are as follows: Figure 4 As shown.

[0027] The present invention will be further illustrated below with specific embodiments.

[0028] Implementation Case 1 This embodiment discloses a patterned display device based on photolithography and mask partitioning deposition to prepare ITO functional layers of different thicknesses. The specific implementation method is as follows: The substrate 101 is a silicon wafer, and the reflective layer 102 is prepared by magnetron sputtering. Pt material is selected and the thickness is 100nm. Then, photolithography is used to obtain a photoresist mask with a corresponding pattern. The pattern is a "pentagram" and the surrounding area, which is divided into regions A and B.

[0029] Based on the above mask, ITO of different thicknesses was deposited in regions A and B using magnetron sputtering, with a thickness of 50 nm in region A and 100 nm in region B. After removing the photoresist mask, a patterned ITO display device was obtained, in which the pentagram area is displayed in purple and the surrounding area is in blue.

[0030] Implementation Case 2 In this implementation, a uniformly deposited ITO functional layer of fixed thickness is used. Then, the electrical heating parameters of different pixel units are controlled by upper and lower cross electrode circuits to achieve differentiated color rendering and ultimately form a patterned display. The specific steps are as follows: A flexible polyimide film was selected as the substrate. The lower electrode connection layer was prepared sequentially by photolithography and magnetron sputtering. The lower electrode connection layer was 50 nm thick, 20 μm wide, and 80 μm spaced. The Pt reflective layer was 100 nm thick and had a visible light reflectivity of ≥90%. The ITO functional layer was a 32×32 pixel array with a single pixel unit size of 100 μm×100 μm. Adjacent pixels were completely separated to form independent controllable pixel units. The ITO layer was 50 nm thick and was initially purple. The SiO2 insulating isolation layer was 20 nm thick. The upper electrode circuit layer was the same as the lower electrode circuit layer.

[0031] Then, the pixel unit is controlled by an external circuit to achieve patterned color display. Using a color contrast table when the ITO thickness is 50nm, it shows purple-red when heated to 200℃, orange-red when heated to 250℃, and orange-pink when heated to 350℃. Color camouflage patterns are generated by an external control unit. The cross-electrode circuitry applies corresponding electrical parameters to the pixel units within the pattern area. For example: simulating vegetation shadow areas: the corresponding pixel receives 3W of power for 10ms (heating temperature 200℃), resulting in a purplish-red color. Simulating soil or tree trunk areas: the corresponding pixel receives 6W of power for 20ms (heating temperature 250℃), resulting in an orange-red color. Simulating highlight or sandy areas: the power receives 9W of power for 30ms (heating temperature 350℃), resulting in an orange-pink color. Simulating dark areas: the pixels are not powered, maintaining their initial purple color. This results in a pixelated ITO display device, which can be applied to dynamic optical camouflage in high-end equipment, special vehicles, or fixed facilities to achieve the desired camouflage patterns.

[0032] like Figure 2 The image shows the reflectance spectrum of an ITO-based color display unit. In the visible light band, the reflectance of ITO varies significantly with different thicknesses, meaning that different colors can be displayed by changing the ITO thickness.

[0033] like Figure 3 The image shows a comparison of the chromaticity coordinates of ITO in the deposited state and after heat treatment at different temperatures. In the visible light band, the display color of the device changes with the thickness of the ITO functional layer, and the change in chromaticity coordinates caused by heat treatment becomes increasingly significant.

[0034] Implementation Case 3 In this implementation, a uniformly deposited ITO functional layer of fixed thickness is used. Then, the electrical heating parameters of different pixel units are controlled by upper and lower cross electrode circuits to achieve differentiated color rendering and ultimately form a patterned display. The specific steps are as follows: A silicon dioxide wafer was selected as the substrate. The lower electrode connection layer was prepared sequentially by photolithography and magnetron sputtering. The lower electrode connection layer was 100 nm thick, 10 μm wide, and 90 μm spaced. The Pt reflective layer was 70 nm thick and had a visible light reflectivity of ≥90%. The ITO functional layer was a 16×16 pixel array with a single pixel unit size of 60 μm×60 μm. Adjacent pixels were completely separated to form independent controllable pixel units with a thickness of 100 nm. The initial state was cyan. The SiO2 insulating isolation layer was 30 nm thick. The upper electrode circuit layer was the same as the lower electrode circuit layer.

[0035] Then, the pixel units are controlled by external circuits to achieve patterned color display. Using a color contrast table with an ITO thickness of 100nm, the color appears cyan-green when heated to 150℃ and dark blue when heated to 250℃.

[0036] Implementation Case 4 In this implementation, a uniformly deposited ITO functional layer of fixed thickness is used. Then, the electrical heating parameters of different pixel units are controlled by upper and lower cross electrode circuits to achieve differentiated color rendering and ultimately form a patterned display. The specific steps are as follows: A silicon dioxide wafer was selected as the substrate. The lower electrode connection layer was prepared sequentially by photolithography and magnetron sputtering. The lower electrode connection layer was 70 nm thick, 30 μm wide, and 100 μm spaced. The Pt reflective layer was 50 nm thick and had a visible light reflectivity of ≥90%. The ITO functional layer was an 8×8 pixel array with a single pixel unit size of 150 μm × 150 μm. Adjacent pixels were completely separated to form independent controllable pixel units with a thickness of 30 nm. The initial state was brownish-yellow. The SiO2 insulating isolation layer was 40 nm thick. The upper electrode circuit layer was the same as the lower electrode circuit layer.

[0037] Then, the pixel units are controlled by external circuits to achieve patterned color display. Using a color contrast table with an ITO thickness of 30nm, the color appears orange-yellow when heated to 150℃ and pale yellow when heated to 250℃.

Claims

1. A controllable pixelated color display device based on ITO, characterized in that, include: Substrate and cross electrode line layer, insulating isolation layer (202), and ITO pixel display array disposed on the substrate; The ITO pixel display array consists of multiple independent ITO color display units arranged in an M×N matrix array. The cross electrode circuit layer includes a lower electrode circuit layer (201) and an upper electrode circuit layer (205). The columns of the M×N matrix correspond to the lower electrode circuit layer (201), and the rows correspond to the upper electrode circuit layer (205). An external circuit is established outside the cross electrode circuit layer. The external circuit adopts a passive matrix drive architecture. The cross electrode circuit layer forms an orthogonal cross matrix structure with the lower electrode circuit layer (201) distributed in columns and the upper electrode circuit layer (205) distributed in rows. Each cross node corresponds to an ITO color display unit. The precise addressing control of a single ITO color display unit is achieved by selectively energizing the lower electrode circuit layer (201) corresponding to the column and the upper electrode circuit layer (205) corresponding to the row. The selective energizing of a single or multiple ITO color display units is achieved by timing control of the external control unit. The insulating layer (202) is used to prevent short circuits between the lower electrode line layer (201) and the upper electrode line layer (205).

2. The controllable pixelated color display device based on ITO according to claim 1, characterized in that, The upper end of the reflective layer (102) of the ITO color display unit is connected to the upper electrode connection layer (205), and the lower end is connected to the lower electrode connection layer (201). An insulating isolation layer (202) is located between the lower electrode connection layer (201) and the upper electrode circuit layer (205); The electrode width of the lower electrode circuit layer (201) and the upper electrode circuit layer (205) is controlled to be 5-40μm, and the electrode spacing is 80-100μm; The passive matrix drive architecture includes a row driver chip, a column driver chip, and an external control unit. The row driver chip outputs a strobe signal, and the column driver chip outputs a drive signal.

3. The controllable pixelated color display device based on ITO according to claim 1, characterized in that, Joule heating of the target ITO color display unit is performed using the cross electrodes of the cross electrode circuit layer. The power and time of the power supply are precisely controlled by the external control unit so that the temperature of the ITO functional layer (103) of the target unit reaches the preset temperature. The crystallization area and grain size of the ITO functional layer (103) are controlled by the heating process, thereby achieving precise color control. The power output ranges from 1 to 10W, adaptable to pixel size (50μm×50μm pixel); the power-on time is 10-60ms; and the preset temperature is 150-350℃.

4. The controllable pixelated color display device based on ITO according to claim 1, characterized in that, In the above-mentioned fabrication of ITO controllable pixelated color display devices, photolithography mask partition deposition is used to achieve differentiated thickness, and partitioned temperature control heating is combined to achieve precise color regulation; and passive matrix driving is adapted to achieve dynamic color display control of the pixel array.

5. A controllable pixelated color display device based on ITO according to claim 1, characterized in that, The ITO color display unit consists of a substrate (101), a reflective layer (102), and an ITO functional layer (103) along the Z-axis direction from bottom to top. The substrate (101), reflective layer (102), and ITO functional layer (103) have the same width; The length of the ITO functional layer (103) is shorter than the lengths of the substrate (101) and the reflective layer (102); The size range of the ITO functional layer (103) is 50-200μm×50-200μm; the substrate (101) and the reflective layer (102) have the same length, ranging from 100-300μm; The reflective layer (102) is used to provide specular reflection, enhance the intensity of reflected light from the ITO functional layer, and improve color display saturation; The ITO functional layer (103) is used to regulate the reflectivity of the device, and the display color is regulated by adjusting the thickness of the ITO functional layer (103).

6. A controllable pixelated color display device based on ITO according to claim 5, characterized in that, The reflective layer (102) is made of a transparent conductive material with a reflectivity of ≥90%, selected from Pt, Ag, and Al, and has a thickness of ≥50 nm. The thickness of the ITO functional layer (103) is in the range of 5 nm ≤ thickness ≤ 100 nm; The mass ratio of conductive indium oxide to tin oxide in the ITO functional layer (103) is 9:

1.

7. A controllable pixelated color display device based on ITO according to claim 6, characterized in that, There is a clear correspondence between the thickness of the ITO functional layer (103) and the reflectance spectrum and display color: When the thickness is 5-15nm: the ITO color display unit displays a bright red; When the thickness is 20-40nm: the ITO color display unit displays a light yellow or neutral color; When the thickness is 40-70nm: the ITO color display unit displays purple; When the thickness is 80-100nm: the ITO color display unit displays blue.

8. A controllable pixelated color display device based on ITO according to claim 7, characterized in that, The above-mentioned ITO color display unit is subjected to programmed heating treatment to achieve secondary precise control and stability optimization of color. The specific heating process parameters are as follows: heating temperature range is 150-350℃, and holding time is 0-10min; The control mechanism of the heat treatment is as follows: by adjusting the heating temperature and holding time, the crystallization region and grain size of the ITO functional layer (103) are precisely controlled. The higher the heating temperature and the longer the holding time, the larger the crystallization region and grain size, thereby changing its dielectric constant and light reflection characteristics, causing the peak of the reflection spectrum to shift, and finally achieving multi-color continuous gradient of the ITO functional layer (103) of the same thickness.

9. A controllable pixelated color display device based on ITO according to claim 6, characterized in that, The reflective layer (102) is prepared on the substrate surface by magnetron sputtering or electron beam evaporation, and the ITO functional layer (103) is deposited on the upper surface of the reflective layer by magnetron sputtering.

10. The application of the controllable pixelated color display device based on ITO as described in any one of claims 1-9, characterized in that, The device is used in smart terminals, AR displays, automotive displays, and wearable devices.

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