WO2017215363A1 - Display device based on phase change material - Google Patents

Display device based on phase change material Download PDF

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Publication number
WO2017215363A1
WO2017215363A1 PCT/CN2017/083131 CN2017083131W WO2017215363A1 WO 2017215363 A1 WO2017215363 A1 WO 2017215363A1 CN 2017083131 W CN2017083131 W CN 2017083131W WO 2017215363 A1 WO2017215363 A1 WO 2017215363A1
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Prior art keywords
phase change
layer
display device
solid phase
change material
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PCT/CN2017/083131
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French (fr)
Chinese (zh)
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缪向水
季宏凯
童浩
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华中科技大学
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Publication of WO2017215363A1 publication Critical patent/WO2017215363A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/0147—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on thermo-optic effects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/0009—Materials therefor
    • G02F1/0054—Structure, phase transitions, NMR, ESR, Moessbauer spectra
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/19—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on variable-reflection or variable-refraction elements not provided for in groups G02F1/015 - G02F1/169

Definitions

  • the present invention belongs to the field of display devices, and more particularly to a display device based on a phase change material.
  • the present invention provides a phase change material-based display device comprising a series of pixel points, each of which includes a reflective layer deposited on a substrate, an isolation layer deposited on the reflective layer, deposited in the a solid phase change layer on the isolation layer and a cover layer deposited on the solid phase change layer; the reflective layer having a reflectance of more than 80% in the visible range for providing back reflection; Adjusting the reflectivity of the entire device; the solid phase change layer is for converting the color of the pixel point under voltage or laser driving; the cover layer is for receiving an externally applied voltage; the solid state is driven by voltage or laser
  • the phase change layer can be reversibly transformed between a crystalline state and an amorphous state, causing a change in the refractive index of the phase change material, thereby causing a change in the color of each pixel.
  • the thickness of the isolation layer may be determined according to a reflectance value required for display.
  • the refractive index of the solid phase change layer is converted between a crystalline state and an amorphous state under an applied voltage or laser induced.
  • phase change material comprises the following sulfur-based compounds and alloys thereof or transition metal oxides including, but not limited to, GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GaSb, GeSbTe, AgInSbTe , InSbTe, AgSbTe, VO, NbO.
  • the atomic percentage is variable.
  • the solid phase change layer comprises two layers, and the materials of the two layers are GeTe and Sb 2 Te 3 , respectively .
  • cover layer and the isolation layer are transparent to light.
  • the material of the cover layer and the isolation layer is a transparent electrode such as indium tin oxide.
  • the thickness of the isolation layer ranges from 10 nm to 300 nm.
  • the display device includes a series of pixel dots arranged in an array, and the display array is formed by spatially structural stacking.
  • the switching speed of the display device based on the phase change material can reach 100 ns or less, and the device size can reach 30 nm or less, and the response speed is fast and the resolution is high. effect.
  • FIG. 1(a), 1(b) and 1(c) are schematic views showing the structure of a display device according to an embodiment of the present invention, wherein FIG. 1(a) shows a structure including a layer of phase change material, and FIG. 1(b) Inclusion The structure of the two-layer phase change material, FIG. 1(c) shows the structure including the n-layer phase change material.
  • FIG. 2(a), 2(b) and 2(c) are reflection spectrum diagrams of a display device in the case of different thickness isolation layers according to an embodiment of the present invention, wherein FIG. 2(a) two layers of phase change materials are Amorphous, Figure 2 (b) wherein one phase change layer is amorphous, the other phase change layer is crystalline, and Figure 2 (c) two phase change layers are crystalline.
  • FIG. 3 is a CIE chromaticity coordinate of a display device at different isolation layer thicknesses and phase change materials in an amorphous and crystalline state, in accordance with an embodiment of the present invention.
  • FIG. 4 is an optical reflectance contrast of a display device at different isolation layer thicknesses according to an embodiment of the present invention
  • FIG. 4(a) is (Rca-Raa)/Raa ⁇ 100
  • FIG. 4(b) is (Rcc-Rca)/ Rca ⁇ 100
  • Raa represents the reflectivity of the device when both 2.1 and 2.2 are amorphous
  • Rca represents 2.1 for the crystalline state
  • 2.2 is the reflectance of the device in the amorphous state
  • Rcc represents the device when both 2.1 and 2.2 are crystalline. Reflectivity. .
  • Figure 5 is a diagram showing the electrode structure of a large pixel array in accordance with one embodiment of the present invention.
  • the present invention is directed to a novel display device which is fast in response, capable of displaying a color image, is easy to prepare, and has an extremely high resolution.
  • the device is compatible with existing commercial electronics industry technologies and can be fabricated on many substrates, such as flexible substrates.
  • the display device comprises: a reflective layer deposited on a substrate, an isolation layer deposited on the reflective layer, a solid phase change layer deposited on the isolation layer, and a cover layer deposited on the solid phase change layer;
  • the reflective layer has a reflectance of more than 80% in the visible light range for providing back reflection; the thickness of the isolation layer can be changed according to a desired reflectance value; the refractive index of the solid phase change layer can be applied with an applied voltage or The laser is induced to transition between a crystalline state and an amorphous state; the cover layer can serve as an electrode layer of the device for receiving an externally applied voltage.
  • the reflectance of the device changes significantly at different light wavelengths.
  • the solid phase change layer can be transformed between a crystalline state and an amorphous state under voltage or laser drive, causing a change in the refractive index of the phase change material, thereby causing a change in the color of the device.
  • the different thickness of the isolation layer causes the reflectance of the device to vary greatly, and the color of the device changes accordingly.
  • the refractive index of the solid phase change layer can be reversibly changed by applying a voltage or a laser on the cover layer and the isolation layer; specifically, applying a long and medium-strength voltage or laser pulse to the phase change material, the phase change material
  • the temperature rises to a temperature range below the melting temperature above the crystallization temperature, and for a certain period of time, the crystal lattice is arranged in an orderly manner to form a crystalline state, thereby realizing the transition from amorphous to crystalline state; applying a short and strong phase change material
  • the voltage or laser pulse causes the temperature of the phase change material to rise above the melting temperature, causing the long-range order of the crystalline state to be destroyed.
  • the pulse falling edge is very short, causing the phase change material to rapidly cool below the crystallization temperature, making the phase change material It is fixed in an amorphous state and realizes a transition from a crystalline state to an amorphous state.
  • the solid phase change layer is in electrical contact with the cover layer and the barrier layer.
  • the phase change material is a mixture of the listed compounds or alloys.
  • the solid phase change layer may further comprise one or more layers of different phase change materials; the individual switching or selection of the state of each phase change material may cause the device to assume multiple colors.
  • the two layers of phase change material comprise GeTe and Sb 2 Te 3 .
  • the crystallization temperature of GeTe is higher than the crystallization temperature of Sb 2 Te 3 , so the states of the GeTe and Sb 2 Te 3 layers can be individually controlled to realize multicolor display, and the phases of GeTe and Sb 2 Te 3
  • the temperature is lower, the voltage required for the transition or the amplitude of the laser is low, and the pulse width is also narrow, so that the power consumption of the device is low and the response speed is fast.
  • the total thickness of the phase change material is less than 60 nm, and a more suitable total thickness is less than 10 nm. Since the thickness of the phase change material is larger, the energy required for crystallization of the phase change material is more, and the contrast of the color of the device is also lower, so the thickness of the phase change material layer is preferably within 10 nm.
  • Both the cover layer and the release layer may be indium tin oxide.
  • the display device has a viewing angle and the isolation layer opposite the phase change material layer from the viewing angle can serve as an electrode layer.
  • the reflective layer is a material having a high reflectivity between the reflective layer and the phase change material.
  • the reflective layer includes Au, Pt, Al, Cu, and Ag.
  • the thickness of the reflective layer is greater than 50 nm, and a suitable thickness is greater than 100 nm to prevent loss of the light source through the reflective layer.
  • phase change material There is a viewing angle surface and a light source for illuminating the phase change material.
  • Three-dimensional display requires a very high image refresh rate (the number of image refreshes per second) to display full-motion video, while the display device of the present invention uses a phase change material, which changes between crystalline and amorphous states.
  • the time is within 100 ns, and the image refresh rate corresponding to the time magnitude is 10 MHz, which is more than 20,000 times that of the current television display technology.
  • the display resolution is the precision of the screen image, which is how many pixels the display can display.
  • the size of the display device can be up to 30 nm, which is 1000 times smaller than the pixel of the current display technology, that is, the resolution of the display device of the present invention is 1000 times higher than the current display technology.
  • FIG. 1 (a), 1 (b) and 1 (c) An embodiment of the invention as shown in Figures 1 (a), 1 (b) and 1 (c) provides a reflective display device.
  • Figure 1 (a) shows only one layer of solid phase change layer 2
  • Figure 1 (b) shows two layers of solid phase change layers 2.1 and 2.2
  • Figure 1 (c) shows that there are n layers of solid phase change layer 2.1 ... 2.
  • n The state of each phase change material in the multilayer solid phase change layer can be individually switched or selected so that the device can assume multiple colors.
  • phase change layer in the case of two solid phase change layers, four different optical properties can be achieved by the following combination of two phase change materials: Amo-Amo, Cry-Amo, Amo-Cry and Cry-Cry (Amo is amorphous) State, Cry is crystalline), different combinations correspond to different colors.
  • the refractive index of the solid phase change layer can be kept stable and can be reversibly changed with the application of a suitable current or laser.
  • the solid phase change layer is a phase change material, and the real and imaginary parts of the refractive index change greatly when transitioning between crystalline and amorphous states.
  • phase change material a long and medium-strength voltage or laser pulse is applied to the phase change material, and the temperature of the phase change material rises to a temperature range below the melting temperature above the crystallization temperature, and is maintained for a certain period of time, and the lattice is sequentially arranged.
  • phase change material Forming a crystalline state to achieve a transition from amorphous to crystalline; applying a short and strong voltage or laser pulse to the phase change material to raise the temperature of the phase change material above the melting temperature, causing the long-range order of the crystalline state to be Destruction, the pulse falling edge is very short, causing the phase change material to rapidly cool below the crystallization temperature, so that the phase change material is fixed in the amorphous state, and the transition from the crystalline state to the amorphous state is realized.
  • FIG. 1(b) the phase change materials are GeTe and Sb 2 Te 3 , respectively .
  • the crystallization temperature of GeTe is higher than the crystallization temperature of Sb 2 Te 3 , so the states of the GeTe and Sb 2 Te 3 layers can be individually controlled to realize multicolor display, and the phases of GeTe and Sb 2 Te 3
  • the temperature is lower, the voltage required for the transition or the amplitude of the laser is low, and the pulse width is also narrow, so that the power consumption of the device is low and the response speed is fast.
  • the reflective layer 5 As shown in Fig. 1(b), in the presently preferred embodiment comprising two layers of material, from bottom to top are the reflective layer 5, the isolating layer 4, the phase change layer 2.2, the phase change layer 2.1 and the cover layer 1.
  • the material of the reflective layer 5 is gold or platinum.
  • the upper surface 8 of the cover layer 1 constitutes the visible side of the display device and the reflective layer 5 is the back reflection. Light enters and exits from the visible surface 8 as shown in Figures 1(a), 1(b), and 1(c). Since the refractive index of the phase change material 2.1, 2.2 and the thickness of the spacer layer 4 affect the interference effect, the reflectance of the device varies greatly at different wavelengths of light.
  • Both the barrier layer 4 and the cover layer 1 can transmit light and should be as transparent as possible.
  • the spacer layer 4 and the cap layer 1 can also serve as electrodes for applying a voltage across the phase change materials 2.1 and 2.2. Therefore, the isolation layer 4 and the cover layer 1 should have a transparent conductive property such as indium tin oxide (ITO).
  • ITO indium tin oxide
  • Figures 1(a), 1(b), 1(c) are grown on a substrate (not shown), such as a silicon wafer, SiO 2 , or a flexible substrate, such as a polymer film.
  • a substrate such as a silicon wafer, SiO 2 , or a flexible substrate, such as a polymer film.
  • the layers of the device were deposited by sputtering and the deposition temperature was guaranteed to be within 100 °C. At the same time, the layers can be patterned by conventional techniques such as photolithography or other techniques.
  • the phase change materials 2.1 and 2.2 are Sb 2 Te 3 and GeTe, respectively, having a thickness of less than 100 nm, preferably less than 10 nm, such as 6 or 7 nm. Since the thickness of the phase change material is larger, the energy required for crystallization of the phase change material is more, and the contrast of the color of the device is also lower, so the thickness of the phase change material layer is preferably within 10 nm.
  • the thickness of the spacer layer 4 typically ranges from 10 nm to 300 nm, the thickness of which depends on the desired color and optical properties.
  • the thickness of the cover layer 1 was 30 nm.
  • the phase change materials 2.1 and 2.2 in this embodiment can be reversibly phase-changeed by application of current or laser exposure.
  • the deposited state of the phase change material is amorphous.
  • Preferred voltages are 2V, 4V, 6V and 8V, with preferred laser powers of 15mW, 20mW, 25mW and 30mW.
  • Different voltages or laser powers cause different phase change materials to phase change, thereby causing the device to produce different optical properties.
  • three different optical properties can be achieved by the following combination of two phase change materials: Amo-Amo, Cry-Amo and Cry-Cry (Amo is amorphous and Cry is crystalline).
  • the optical characteristics of the devices of the three different combinations are clarified in this embodiment, and the optical characteristics of the device of the other Amo-Cry combination are not described, but are also within the scope of protection of this patent.
  • the refractive index varies greatly as the phase change material transitions between crystalline and amorphous states.
  • the phase change material is stable in both states. This means when the display When in a stable state (non-transition), the voltage or laser can be removed, so the power consumption of the device is very low.
  • the conversion speed is also very fast, less than 100ns, several times faster than human glasses can perceive.
  • FIG. 2(a), 2(b) and 2(c) show the reflectance of the device shown in Fig. 1(b).
  • Figures 2(a), 2(b) and 2(c) show the change in reflectance between different phases depending on the wavelength of the incident light. It also shows the effect of the thickness of the different isolation layer 4 on the reflectance peaks and trough positions.
  • the device of Fig. 1(b) will appear in a special color and the color of the device will be different by selecting the thickness of the different isolation layer 4. At the same time, the color of the device changes with the transition of crystalline and amorphous phases of phase change materials 2.1 and 2.2.
  • Figure 3 shows another device color representation.
  • Figure 3 shows the CIE partial chrominance space and plots the xy chromaticity coordinates of the device color, all under the 2 degree field of view and the D50 source.
  • the thickness of each spacer 4 is indicated by the symbol on the right side of FIG.
  • 2.1 is crystalline 2.2 is amorphous
  • the left side of the symbol is *
  • 2.1 and 2.2 are crystalline
  • the left side of the symbol is #
  • 2.1 and 2.2 are amorphous, there is no other sign on the left.
  • the thickness of the different spacer layers 4 can produce a wide range of colors. Also, in most cases, the color of the combination of phase change materials 2.1 and 2.2 different phases is very different.
  • Figures 4(a) and 4(b) show optical reflectance comparisons between the different phases of layers 2.1 and 2.2.
  • Figure 4 (a) is (Rca-Raa) / Raa ⁇ 100
  • Figure 4 (b) is (Rcc - Rca) / Rca ⁇ 100
  • Raa represents the reflectivity of the device when both 2.1 and 2.2 are amorphous
  • 2.2 represents the reflectivity of the device in the amorphous state
  • Rcc represents the reflectance of the device when both 2.1 and 2.2 are crystalline.
  • the thickness of the different isolation layers 4 the reflectance of a specific wavelength can be greatly modulated.
  • the display device of Fig. 1(b) is capable of producing a uniform color, and can also be converted to a high contrast color, or by changing the reflectance to obtain a darker or brighter color.
  • many of the structures as shown in Figure 1(b) are interconnected to form an array, and each structure can be individually controlled to apply a voltage or laser to form a pixel in the entire display.
  • each pixel is composed of several structures (referred to as sub-pixels) as shown in FIG. 1(b), but each sub-pixel isolation layer 4 in the pixel has a different thickness. In this way, each sub-pixel in a pixel can be converted between three colors, and the pixel can exhibit a wider color than just switching between the three colors.
  • the number of sub-pixels of different thicknesses in the pixel may be three or more.
  • phase change material layers 2.1 and 2.2 do not need to be switched between fully crystalline and fully amorphous.
  • the mixed phase can be obtained by, for example, 20% crystallization, 40% crystallization, or the like. Partial crystallization can be achieved simply by limiting the maximum current or laser power during the conversion process.
  • the refractive index of a material between completely amorphous and fully crystallized depends on the degree of partial crystallization. A phase between 16 and 64 mixed phases is typically obtained. And under the appropriate control, you can get more phases, such as 1024.
  • Figure 5 is a top plan view of an array of display device electrodes in accordance with one embodiment of the present invention.
  • the substrate 10 is used as a reflective layer for each pixel.
  • 12.1, 12.2, 12.3, ..., 12.n are horizontal electrodes. These electrodes constitute the isolation layer 4.
  • a solid phase change layer is patterned in a pattern on top of the isolation layer 4.
  • a series of vertical electrodes 11.1, 11.2, 11.3, 11.4, ..., 11.n were prepared.
  • the reflective layer and the solid phase change layer need only exist at the intersection of the horizontal and vertical electrodes. All fabrication, deposition and patterning can be performed using known photolithographic techniques.
  • each of the horizontal and vertical electrodes constitutes a stacked structure as shown in Fig. 1(b).
  • the thickness of the spacer/horizontal (bottom) electrodes are different, respectively, so that each pixel point can exhibit different color ranges as shown in FIGS. 2 to 4.
  • the phase change material in the pixel can be converted as desired.
  • the other pixels in the array are not affected, so the addressing of the pixels is simple.
  • the transformation mechanism is not limited to the application of current pulse induced heating, any other electromagnetic field induced heating, such as a laser pulse, or induction heating using an electrical resistance heating method in an adjacent layer in thermal contact with the phase change material.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

Disclosed is a display device on the basis of phase change material, comprising a series of pixels, each pixel comprising a reflective layer (5) deposited on the substrate (10), a spacer layer (4) deposited on the reflective layer (5), a solid phase change layer (2, 2.1-2.n) deposited on the spacer layer (4) and a cladding layer (1) deposited on the solid phase change layer (2, 2.1-2.n). The reflective layer (5) has a reflectance of 80% or more in the visible light range and is used for providing a back reflection. The spacer layer (4) is used for adjusting a reflectivity of the entire device. The solid phase change layer (2, 2.1-2.n) can be reversibly changed between a crystalline and an amorphous states under the driving of voltage or laser, causing a change in the refractive index of the phase change material, so that the color of each pixel is changed. The cladding layer (1) is used to receive an externally applied voltage. A large number of pixels can be stacked according to a spatial structure to form a display array.

Description

一种基于相变材料的显示器件Display device based on phase change material 【技术领域】[Technical Field]
本发明属于显示器件领域，更具体地，涉及一种基于相变材料的显示器件。The present invention belongs to the field of display devices, and more particularly to a display device based on a phase change material.
【背景技术】【Background technique】
在显示技术领域有许多引人注目的进步，例如便携式计算机和通信设备。其中一些显示技术例如背光式彩色显示器功耗高且制备难度大。虽然别的技术可以提供无背光的黑白显示，但是他们的响应速度慢，所以不适合显示视频，并且缺少彩色显示。而且这些技术都很难生成高分辨率的图像。There are many striking advances in the field of display technology, such as portable computers and communication devices. Some of these display technologies, such as backlit color displays, have high power consumption and are difficult to prepare. While other technologies can provide black and white displays without backlighting, their response is slow, so they are not suitable for displaying video and lack color display. And these techniques are difficult to generate high-resolution images.
【发明内容】[Summary of the Invention]
针对现有技术的缺陷，本发明的目的在于提供一种基于相变材料的显示器件，现有技术的显示器件大多采用的是低分子液晶，其分子长2nm～3nm，直径约0.5nm，但利用这种分子级别的材料制成的显示器，其响应速度只能达到毫秒级，且其器件大小只有微米级，所以导致响应速度慢、分辨率低。In view of the defects of the prior art, an object of the present invention is to provide a display device based on a phase change material. Most of the display devices of the prior art use a low molecular liquid crystal having a molecular length of 2 nm to 3 nm and a diameter of about 0.5 nm. Displays made from this molecular-grade material can only respond to milliseconds in response speed and have a device size of only micrometers, resulting in slow response and low resolution.
本发明提供了一种基于相变材料的显示器件，包括一系列像素点，其每个像素点包括沉积在衬底上的反射层、沉积在所述反射层上的隔离层、沉积在所述隔离层上的固态相变层和沉积在所述固态相变层上的覆盖层；所述反射层在可见光范围内拥有80％以上的反射率，用于提供背面反射；所述隔离层用于调节整个器件的反射率；所述固态相变层用于在电压或者激光驱动下使像素点的颜色进行转换；所述覆盖层用于接收外部施加的电压；在电压或者激光驱动下所述固态相变层可以在晶态和非晶态之间可逆转变，引起相变材料折射率的变化，从而使得每个像素点的颜色发生改变。 The present invention provides a phase change material-based display device comprising a series of pixel points, each of which includes a reflective layer deposited on a substrate, an isolation layer deposited on the reflective layer, deposited in the a solid phase change layer on the isolation layer and a cover layer deposited on the solid phase change layer; the reflective layer having a reflectance of more than 80% in the visible range for providing back reflection; Adjusting the reflectivity of the entire device; the solid phase change layer is for converting the color of the pixel point under voltage or laser driving; the cover layer is for receiving an externally applied voltage; the solid state is driven by voltage or laser The phase change layer can be reversibly transformed between a crystalline state and an amorphous state, causing a change in the refractive index of the phase change material, thereby causing a change in the color of each pixel.
更进一步地，所述隔离层的厚度可以根据显示需要的反射率值来确定。Further, the thickness of the isolation layer may be determined according to a reflectance value required for display.
更进一步地，所述固态相变层的折射率在外加电压或激光诱导下在晶态和非晶态之间转变。Further, the refractive index of the solid phase change layer is converted between a crystalline state and an amorphous state under an applied voltage or laser induced.
更进一步地，所述固态相变层包括一层或多层不同的相变材料，通过分别对每层相变材料的状态进行单独控制使得所述显示器件呈现多种颜色。Still further, the solid phase change layer includes one or more layers of different phase change materials, and the display device exhibits a plurality of colors by separately controlling the state of each layer of the phase change material separately.
更进一步地，所述的相变材料包括下列硫系化合物及其合金或过渡金属氧化物，包括但不限于：GeTe，SbTe,BiTe,InSb,InSe,GeSb,SbSe,GaSb,GaSb,GeSbTe，AgInSbTe,InSbTe,AgSbTe,VO,NbO。其中原子百分比可变。Further, the phase change material comprises the following sulfur-based compounds and alloys thereof or transition metal oxides including, but not limited to, GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GaSb, GeSbTe, AgInSbTe , InSbTe, AgSbTe, VO, NbO. The atomic percentage is variable.
更进一步地，所述固态相变层的材料还包含至少一种掺杂剂。Further, the material of the solid phase change layer further comprises at least one dopant.
更进一步地，所述固态相变层包括两层，两层的材料分别为GeTe和Sb2Te3。Further, the solid phase change layer comprises two layers, and the materials of the two layers are GeTe and Sb 2 Te 3 , respectively .
更进一步地，所述固态相变层的厚度小于60nm。Further, the thickness of the solid phase change layer is less than 60 nm.
更进一步地，所述固态相变层的厚度小于10nm。Further, the thickness of the solid phase change layer is less than 10 nm.
更进一步地，所述覆盖层和所述隔离层对光透明。Further, the cover layer and the isolation layer are transparent to light.
更进一步地，所述覆盖层和隔离层的材料为透明电极，如铟锡氧化物。Further, the material of the cover layer and the isolation layer is a transparent electrode such as indium tin oxide.
更进一步地，所述隔离层厚度范围为10nm-300nm。Further, the thickness of the isolation layer ranges from 10 nm to 300 nm.
更进一步地，所述显示器件包括一系列排成阵列的像素点，通过空间上的结构堆叠形成显示阵列。Still further, the display device includes a series of pixel dots arranged in an array, and the display array is formed by spatially structural stacking.
通过本发明所构思的以上技术方案，与现有技术相比，基于相变材料的显示器件的开关速度可以达到100ns以内，器件大小可以达到30nm以内，能够取得响应速度快，分辨率高的有益效果。According to the above technical solution conceived by the present invention, compared with the prior art, the switching speed of the display device based on the phase change material can reach 100 ns or less, and the device size can reach 30 nm or less, and the response speed is fast and the resolution is high. effect.
【附图说明】[Description of the Drawings]
图1(a)，图1(b)和图1(c)是本发明实施例的显示器件的结构示意图，其中图1(a)表示包含一层相变材料的结构，图1(b)表示包含 两层相变材料的结构，图1(c)表示包含n层相变材料的结构。1(a), 1(b) and 1(c) are schematic views showing the structure of a display device according to an embodiment of the present invention, wherein FIG. 1(a) shows a structure including a layer of phase change material, and FIG. 1(b) Inclusion The structure of the two-layer phase change material, FIG. 1(c) shows the structure including the n-layer phase change material.
图2(a)，2(b)和2(c)是根据本发明实施例的显示器件在不同厚度隔离层情况下的反射光谱图，其中，图2(a)两层相变材料均为非晶态，图2(b)其中一层相变层为非晶态，另一层相变层为晶态，图2(c)两层相变层均为晶态。2(a), 2(b) and 2(c) are reflection spectrum diagrams of a display device in the case of different thickness isolation layers according to an embodiment of the present invention, wherein FIG. 2(a) two layers of phase change materials are Amorphous, Figure 2 (b) wherein one phase change layer is amorphous, the other phase change layer is crystalline, and Figure 2 (c) two phase change layers are crystalline.
图3是根据本发明实施例显示器件在不同隔离层厚度和相变材料在非晶和晶态下的CIE色度坐标。3 is a CIE chromaticity coordinate of a display device at different isolation layer thicknesses and phase change materials in an amorphous and crystalline state, in accordance with an embodiment of the present invention.
图4是根据本发明实施例显示器件在不同隔离层厚度下的光学反射率对比度；图4(a)为(Rca-Raa)/Raa×100，图4(b)为(Rcc-Rca)/Rca×100，其中Raa代表2.1和2.2均为非晶态时器件的反射率，Rca代表2.1为晶态，2.2为非晶态时器件的反射率，Rcc代表2.1和2.2均为晶态时器件的反射率。。4 is an optical reflectance contrast of a display device at different isolation layer thicknesses according to an embodiment of the present invention; FIG. 4(a) is (Rca-Raa)/Raa×100, and FIG. 4(b) is (Rcc-Rca)/ Rca×100, where Raa represents the reflectivity of the device when both 2.1 and 2.2 are amorphous, Rca represents 2.1 for the crystalline state, 2.2 is the reflectance of the device in the amorphous state, and Rcc represents the device when both 2.1 and 2.2 are crystalline. Reflectivity. .
图5是根据本发明一个实施例的大型像素阵列的电极结构图。Figure 5 is a diagram showing the electrode structure of a large pixel array in accordance with one embodiment of the present invention.
【具体实施方式】【detailed description】
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
本发明旨在提供一种新型的显示器件，其响应速度快，能显示彩色图像，易于制备并且拥有极高的分辨率。该器件与现有的商业电子工业技术相匹配，能制备在许多衬底上，例如柔性衬底。SUMMARY OF THE INVENTION The present invention is directed to a novel display device which is fast in response, capable of displaying a color image, is easy to prepare, and has an extremely high resolution. The device is compatible with existing commercial electronics industry technologies and can be fabricated on many substrates, such as flexible substrates.
本发明提供的显示器件包括：沉积在衬底上的反射层、沉积在反射层上的隔离层、沉积在隔离层上的固态相变层和沉积在固态相变层上的覆盖层；所述反射层在可见光范围内拥有80％以上的反射率，用来提供背面反射；所述隔离层的厚度可以根据需要的反射率值来改变；所述固态相变层的折射率可以在外加电压或激光诱导下在晶态和非晶态之间转变；所述的覆盖层可以作为器件的电极层，用于接收外部施加的电压。 The display device provided by the present invention comprises: a reflective layer deposited on a substrate, an isolation layer deposited on the reflective layer, a solid phase change layer deposited on the isolation layer, and a cover layer deposited on the solid phase change layer; The reflective layer has a reflectance of more than 80% in the visible light range for providing back reflection; the thickness of the isolation layer can be changed according to a desired reflectance value; the refractive index of the solid phase change layer can be applied with an applied voltage or The laser is induced to transition between a crystalline state and an amorphous state; the cover layer can serve as an electrode layer of the device for receiving an externally applied voltage.
由于固态相变层的折射率和隔离层的厚度影响干涉效应，所以器件的反射率在不同光波长下变化明显。在电压或者激光驱动下固态相变层可以在晶态和非晶态之间转变，引起相变材料折射率的变化，从而使得器件的颜色发生改变。不同厚度的隔离层使器件的反射率变化很大，从而器件的颜色也相应的变化。Since the refractive index of the solid phase change layer and the thickness of the isolation layer affect the interference effect, the reflectance of the device changes significantly at different light wavelengths. The solid phase change layer can be transformed between a crystalline state and an amorphous state under voltage or laser drive, causing a change in the refractive index of the phase change material, thereby causing a change in the color of the device. The different thickness of the isolation layer causes the reflectance of the device to vary greatly, and the color of the device changes accordingly.
所述固态相变层的折射率可以通过在覆盖层和隔离层上施加电压或者激光来可逆的改变；具体地，对相变材料施加一个长且强度中等的电压或者激光脉冲，相变材料的温度升高到结晶温度以上熔化温度以下的温度区间，并保持一定的时间，晶格此时有序排列形成晶态，实现由非晶向晶态的转变；对相变材料施加一个短而强的电压或者激光脉冲，使相变材料温度升高到熔化温度以上，使晶态的长程有序遭到破坏，脉冲下降沿非常短导致相变材料经快速冷却至结晶温度以下，使相变材料固定于非晶态，实现由晶态向非晶态转变。The refractive index of the solid phase change layer can be reversibly changed by applying a voltage or a laser on the cover layer and the isolation layer; specifically, applying a long and medium-strength voltage or laser pulse to the phase change material, the phase change material The temperature rises to a temperature range below the melting temperature above the crystallization temperature, and for a certain period of time, the crystal lattice is arranged in an orderly manner to form a crystalline state, thereby realizing the transition from amorphous to crystalline state; applying a short and strong phase change material The voltage or laser pulse causes the temperature of the phase change material to rise above the melting temperature, causing the long-range order of the crystalline state to be destroyed. The pulse falling edge is very short, causing the phase change material to rapidly cool below the crystallization temperature, making the phase change material It is fixed in an amorphous state and realizes a transition from a crystalline state to an amorphous state.
固态相变层与覆盖层和隔离层之间通过电学接触。The solid phase change layer is in electrical contact with the cover layer and the barrier layer.
固态相变层的材料可以为相变材料，包括下列硫系化合物及其合金或过渡金属氧化物，包括但不限于：GeTe，SbTe,BiTe,InSb,InSe,GeSb,SbSe,GaSb,GaSb,GeSbTe，AgInSbTe,InSbTe,AgSbTe,VO,NbO。其中原子百分比可变。The material of the solid phase change layer may be a phase change material, including the following sulfur-based compounds and alloys thereof or transition metal oxides including, but not limited to, GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GaSb, GeSbTe , AgInSbTe, InSbTe, AgSbTe, VO, NbO. The atomic percentage is variable.
相变材料由所述列表的化合物或者合金混合而成。The phase change material is a mixture of the listed compounds or alloys.
相变材料可进一步包含至少一种掺杂剂。The phase change material may further comprise at least one dopant.
固态相变层可进一步包含一层或者多层不同的相变材料；对每层相变材料的状态单独的开关或者选择可以使器件呈现多种颜色。The solid phase change layer may further comprise one or more layers of different phase change materials; the individual switching or selection of the state of each phase change material may cause the device to assume multiple colors.
优选地，两层相变材料包含GeTe和Sb2Te3。其中GeTe的晶化温度比Sb2Te3的晶化温度高，所以GeTe和Sb2Te3各层的状态可以被单独的控制，从而实现多色的显示，并且GeTe和Sb2Te3的相变温度较低，转变所需的电压或者激光的幅值低，脉冲宽度也较窄，使得器件的功耗低，响应速度快。 Preferably, the two layers of phase change material comprise GeTe and Sb 2 Te 3 . Wherein the crystallization temperature of GeTe is higher than the crystallization temperature of Sb 2 Te 3 , so the states of the GeTe and Sb 2 Te 3 layers can be individually controlled to realize multicolor display, and the phases of GeTe and Sb 2 Te 3 The temperature is lower, the voltage required for the transition or the amplitude of the laser is low, and the pulse width is also narrow, so that the power consumption of the device is low and the response speed is fast.
其中，两层相变材料依次堆叠。Among them, two layers of phase change materials are stacked in sequence.
优选地，相变材料的总厚度少于60nm，较合适的总厚度为少于10nm。由于相变材料的厚度越大，相变材料晶化所需的能量也就越多，同时器件颜色的对比度也会越低，所以相变材料层的厚度在10nm以内较合适。Preferably, the total thickness of the phase change material is less than 60 nm, and a more suitable total thickness is less than 10 nm. Since the thickness of the phase change material is larger, the energy required for crystallization of the phase change material is more, and the contrast of the color of the device is also lower, so the thickness of the phase change material layer is preferably within 10 nm.
覆盖层和隔离层均可以为铟锡氧化物。Both the cover layer and the release layer may be indium tin oxide.
显示器件拥有一个视角面并且从视角面来看相变材料层对立面的隔离层可以作为电极层。The display device has a viewing angle and the isolation layer opposite the phase change material layer from the viewing angle can serve as an electrode layer.
反射层为具有高反射率的材料，隔离层在反射层与相变材料之间。The reflective layer is a material having a high reflectivity between the reflective layer and the phase change material.
反射层包括Au，Pt，Al，Cu和Ag，反射层的厚度大于50nm，较合适的厚度为大于100nm，以防止光源穿过反射层造成损耗。The reflective layer includes Au, Pt, Al, Cu, and Ag. The thickness of the reflective layer is greater than 50 nm, and a suitable thickness is greater than 100 nm to prevent loss of the light source through the reflective layer.
其中，拥有一个视角面和一个光源，该光源用来照射相变材料。There is a viewing angle surface and a light source for illuminating the phase change material.
其中，通过在电极上施加电流穿过相变材料，或者通过激光照射相变材料来控制相变材料的折射率。Therein, the refractive index of the phase change material is controlled by applying a current through the phase change material on the electrode or by irradiating the phase change material with a laser.
显示器件包括一系列排成阵列的相变材料，其中每个相变材料的折射率都能够通过像素寻址来单独控制。The display device includes a series of phase change materials arranged in an array, wherein the refractive index of each phase change material can be individually controlled by pixel addressing.
三维显示需要非常高的图像刷新率(每秒钟图像刷新的次数)来显示全动态的视频，而本发明所述的显示器件采用相变材料，其在晶态与非晶态之间的转变时间在100ns以内，该时间量级对应的图像刷新率为10MHz，超过目前的电视显示技术20000倍。显示分辨率是屏幕图像的精密度，是指显示器所能显示的像素有多少。所述显示器件的尺寸可以达到30nm以内，比目前显示技术的像素点小了1000倍，也就是说本发明所述的显示器件的分辨率超过目前的显示技术1000倍。Three-dimensional display requires a very high image refresh rate (the number of image refreshes per second) to display full-motion video, while the display device of the present invention uses a phase change material, which changes between crystalline and amorphous states. The time is within 100 ns, and the image refresh rate corresponding to the time magnitude is 10 MHz, which is more than 20,000 times that of the current television display technology. The display resolution is the precision of the screen image, which is how many pixels the display can display. The size of the display device can be up to 30 nm, which is 1000 times smaller than the pixel of the current display technology, that is, the resolution of the display device of the present invention is 1000 times higher than the current display technology.
为了使本发明的目的，技术方案更加清楚，下面将结合附图说明对本发明作进一步地详细说明，显然所描述的实施例仅仅是本发明的一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护 的范围。The present invention will be further described in detail with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are protected by the present invention. The scope.
如图1(a)，1(b)和1(c)所示的本发明实施例提供一种反射式显示器件。图1(a)表示仅有一层固态相变层2，图1(b)表示有两层固态相变层2.1和2.2，图1(c)表示有n层固态相变层2.1……2.n。多层固态相变层中的每层相变材料的状态都可以单独的开关或者选择，从而器件可以呈现多种颜色。例如在两层固态相变层情况下，四种不同的光学特性可以通过两种相变材料的以下组合来实现：Amo-Amo，Cry-Amo，Amo-Cry和Cry-Cry(Amo为非晶态，Cry为晶态)，不同的组合对应不同的颜色。固态相变层的折射率能保持稳定并且在施加合适的电流或者激光情况下可以可逆的变化。固态相变层是一种相变材料，在晶态和非晶态之间转变的时候其折射率的实部和虚部会发生很大的变化。具体地，对相变材料施加一个长且强度中等的电压或者激光脉冲，相变材料的温度升高到结晶温度以上熔化温度以下的温度区间，并保持一定的时间，晶格此时有序排列形成晶态，实现由非晶向晶态的转变；对相变材料施加一个短而强的电压或者激光脉冲，使相变材料温度升高到熔化温度以上，使晶态的长程有序遭到破坏，脉冲下降沿非常短导致相变材料经快速冷却至结晶温度以下，使相变材料固定于非晶态，实现由晶态向非晶态转变。以下实施例均以图1(b)为例具体说明，在目前优选的包含两层相变材料的实施例中，相变材料分别为GeTe和Sb2Te3。其中GeTe的晶化温度比Sb2Te3的晶化温度高，所以GeTe和Sb2Te3各层的状态可以被单独的控制，从而实现多色的显示，并且GeTe和Sb2Te3的相变温度较低，转变所需的电压或者激光的幅值低，脉冲宽度也较窄，使得器件的功耗低，响应速度快。An embodiment of the invention as shown in Figures 1 (a), 1 (b) and 1 (c) provides a reflective display device. Figure 1 (a) shows only one layer of solid phase change layer 2, Figure 1 (b) shows two layers of solid phase change layers 2.1 and 2.2, Figure 1 (c) shows that there are n layers of solid phase change layer 2.1 ... 2. n. The state of each phase change material in the multilayer solid phase change layer can be individually switched or selected so that the device can assume multiple colors. For example, in the case of two solid phase change layers, four different optical properties can be achieved by the following combination of two phase change materials: Amo-Amo, Cry-Amo, Amo-Cry and Cry-Cry (Amo is amorphous) State, Cry is crystalline), different combinations correspond to different colors. The refractive index of the solid phase change layer can be kept stable and can be reversibly changed with the application of a suitable current or laser. The solid phase change layer is a phase change material, and the real and imaginary parts of the refractive index change greatly when transitioning between crystalline and amorphous states. Specifically, a long and medium-strength voltage or laser pulse is applied to the phase change material, and the temperature of the phase change material rises to a temperature range below the melting temperature above the crystallization temperature, and is maintained for a certain period of time, and the lattice is sequentially arranged. Forming a crystalline state to achieve a transition from amorphous to crystalline; applying a short and strong voltage or laser pulse to the phase change material to raise the temperature of the phase change material above the melting temperature, causing the long-range order of the crystalline state to be Destruction, the pulse falling edge is very short, causing the phase change material to rapidly cool below the crystallization temperature, so that the phase change material is fixed in the amorphous state, and the transition from the crystalline state to the amorphous state is realized. The following examples are specifically illustrated by taking FIG. 1(b) as an example. In the presently preferred embodiment comprising two layers of phase change materials, the phase change materials are GeTe and Sb 2 Te 3 , respectively . Wherein the crystallization temperature of GeTe is higher than the crystallization temperature of Sb 2 Te 3 , so the states of the GeTe and Sb 2 Te 3 layers can be individually controlled to realize multicolor display, and the phases of GeTe and Sb 2 Te 3 The temperature is lower, the voltage required for the transition or the amplitude of the laser is low, and the pulse width is also narrow, so that the power consumption of the device is low and the response speed is fast.
如图1(b)，在目前优选的包含两层材料的实施例中，从下到上依次是反射层5，隔离层4，相变层2.2，相变层2.1和覆盖层1。其中反射层5的材料为金或铂。覆盖层1的上表面8构成该显示器件的可视面，反射层5是背部反射。如图1(a)，1(b)，1(c)所示光从可视面8进入和穿出。 由于相变材料2.1，2.2的折射率和隔离层4的厚度影响干涉效应，所以器件的反射率在不同的光波长下变化很大。As shown in Fig. 1(b), in the presently preferred embodiment comprising two layers of material, from bottom to top are the reflective layer 5, the isolating layer 4, the phase change layer 2.2, the phase change layer 2.1 and the cover layer 1. The material of the reflective layer 5 is gold or platinum. The upper surface 8 of the cover layer 1 constitutes the visible side of the display device and the reflective layer 5 is the back reflection. Light enters and exits from the visible surface 8 as shown in Figures 1(a), 1(b), and 1(c). Since the refractive index of the phase change material 2.1, 2.2 and the thickness of the spacer layer 4 affect the interference effect, the reflectance of the device varies greatly at different wavelengths of light.
隔离层4和覆盖层1均可以传输光，而且应该尽可能的透明。在本实施例中，隔离层4和覆盖层1还可以作为电极，用来在相变材料2.1和2.2上施加电压。所以隔离层4和覆盖层1应该具有透明导电的特性，如氧化铟锡(ITO)。Both the barrier layer 4 and the cover layer 1 can transmit light and should be as transparent as possible. In this embodiment, the spacer layer 4 and the cap layer 1 can also serve as electrodes for applying a voltage across the phase change materials 2.1 and 2.2. Therefore, the isolation layer 4 and the cover layer 1 should have a transparent conductive property such as indium tin oxide (ITO).
图1(a)，1(b)，1(c)中的结构生长在衬底上(没有在图中显示)，如硅片，SiO2，或者柔性衬底，如聚合物薄膜。器件各层用溅射方法来沉积，并且保证沉积温度在100℃以内。同时各层可以通过传统技术如光刻或其他技术来得到图案。The structures in Figures 1(a), 1(b), 1(c) are grown on a substrate (not shown), such as a silicon wafer, SiO 2 , or a flexible substrate, such as a polymer film. The layers of the device were deposited by sputtering and the deposition temperature was guaranteed to be within 100 °C. At the same time, the layers can be patterned by conventional techniques such as photolithography or other techniques.
在优选的实施例中，相变材料2.1和2.2，分别为Sb2Te3和GeTe，其厚度小于100nm，优选的厚度小于10nm，如6或者7nm。由于相变材料的厚度越大，相变材料晶化所需的能量也就越多，同时器件颜色的对比度也会越低，所以相变材料层的厚度在10nm以内较合适。隔离层4的厚度典型范围为10nm到300nm，其厚度取决于所需要的颜色和光学性能。覆盖层1的厚度为30nm。In a preferred embodiment, the phase change materials 2.1 and 2.2 are Sb 2 Te 3 and GeTe, respectively, having a thickness of less than 100 nm, preferably less than 10 nm, such as 6 or 7 nm. Since the thickness of the phase change material is larger, the energy required for crystallization of the phase change material is more, and the contrast of the color of the device is also lower, so the thickness of the phase change material layer is preferably within 10 nm. The thickness of the spacer layer 4 typically ranges from 10 nm to 300 nm, the thickness of which depends on the desired color and optical properties. The thickness of the cover layer 1 was 30 nm.
在本实施中的相变材料2.1和2.2可以通过施加电流或者激光曝光来可逆相变。相变材料的沉积态为非晶态。优选的电压为2V，4V，6V和8V，优选的激光功率为15mW，20mW，25mW和30mW。不同的电压或者激光功率使得不同的相变材料相变，从而使器件产生不同的光学特性。在本实施例中，三种不同的光学特性可以通过两种相变材料的以下组合来实现：Amo-Amo，Cry-Amo和Cry-Cry(Amo为非晶态，Cry为晶态)。在本实施例中阐明了这三种不同组合的器件光学特性，另外一种Amo-Cry组合的器件光学特性并未说明，但也在本专利的保护范围之类。The phase change materials 2.1 and 2.2 in this embodiment can be reversibly phase-changeed by application of current or laser exposure. The deposited state of the phase change material is amorphous. Preferred voltages are 2V, 4V, 6V and 8V, with preferred laser powers of 15mW, 20mW, 25mW and 30mW. Different voltages or laser powers cause different phase change materials to phase change, thereby causing the device to produce different optical properties. In this embodiment, three different optical properties can be achieved by the following combination of two phase change materials: Amo-Amo, Cry-Amo and Cry-Cry (Amo is amorphous and Cry is crystalline). The optical characteristics of the devices of the three different combinations are clarified in this embodiment, and the optical characteristics of the device of the other Amo-Cry combination are not described, but are also within the scope of protection of this patent.
正如之前阐明的那样，当相变材料在晶态和非晶态之间转变的时候其折射率变化很大。相变材料在两种状态下均是稳定的。这意味着当显示器 处在稳定的状态下时(非转变)，可以移除电压或者激光，所以该器件的功耗很低。转换速度同样很快，小于100ns，比人类眼镜可以感知的速度快好几倍。As previously stated, the refractive index varies greatly as the phase change material transitions between crystalline and amorphous states. The phase change material is stable in both states. This means when the display When in a stable state (non-transition), the voltage or laser can be removed, so the power consumption of the device is very low. The conversion speed is also very fast, less than 100ns, several times faster than human glasses can perceive.
图2(a)，图2(b)和图2(c)为图1(b)所示器件的反射率。在隔离层4特定的厚度下，图2(a)，图2(b)和图2(c)展现了根据入射光波长反射率在不同相之间的变化。同时也表明了不同的隔离层4厚度对反射率波峰和波谷位置的影响。2(a), 2(b) and 2(c) show the reflectance of the device shown in Fig. 1(b). At a particular thickness of the barrier layer 4, Figures 2(a), 2(b) and 2(c) show the change in reflectance between different phases depending on the wavelength of the incident light. It also shows the effect of the thickness of the different isolation layer 4 on the reflectance peaks and trough positions.
因此，图1(b)的器件就会出现特别的颜色并且通过选择不同的隔离层4的厚度，器件的颜色也不同。同时器件的颜色会随着相变材料2.1和2.2晶态和非晶态的转变而变化。Therefore, the device of Fig. 1(b) will appear in a special color and the color of the device will be different by selecting the thickness of the different isolation layer 4. At the same time, the color of the device changes with the transition of crystalline and amorphous phases of phase change materials 2.1 and 2.2.
图3表示了另外一种器件颜色表示方式。图3展现了CIE部分色度空间并且画出了器件颜色的xy色度坐标，所有颜色均在2度视场和D50光源下。每个隔离层4厚度由图3右边的符号标出。每个符号下色度空间中均有三个不同的点，分别对应相变材料2.1和2.2的不同状态。2.1为晶态2.2为非晶的符号左边有*，2.1和2.2均为晶态的符号左边有#，2.1和2.2均为非晶态的符号左边无其它标志。从图中可以看出，不同隔离层4的厚度可以生成范围广泛的颜色。并且，在大部分情况下，相变材料2.1和2.2不同相的组合的颜色差别很大。Figure 3 shows another device color representation. Figure 3 shows the CIE partial chrominance space and plots the xy chromaticity coordinates of the device color, all under the 2 degree field of view and the D50 source. The thickness of each spacer 4 is indicated by the symbol on the right side of FIG. There are three different points in the chromaticity space under each symbol, corresponding to different states of phase change materials 2.1 and 2.2, respectively. 2.1 is crystalline 2.2 is amorphous, the left side of the symbol is *, 2.1 and 2.2 are crystalline, the left side of the symbol is #, 2.1 and 2.2 are amorphous, there is no other sign on the left. As can be seen from the figure, the thickness of the different spacer layers 4 can produce a wide range of colors. Also, in most cases, the color of the combination of phase change materials 2.1 and 2.2 different phases is very different.
图4(a)和图4(b)展现了层2.1和2.2不同相之间的光学反射率对比。图4(a)为(Rca-Raa)/Raa×100，图4(b)为(Rcc-Rca)/Rca×100，其中Raa代表2.1和2.2均为非晶态时器件的反射率，Rca代表2.1为晶态，2.2为非晶态时器件的反射率，Rcc代表2.1和2.2均为晶态时器件的反射率。从图中可以看出，通过选择不同隔离层4的厚度，特定波长的反射率可以得到很大的调制。Figures 4(a) and 4(b) show optical reflectance comparisons between the different phases of layers 2.1 and 2.2. Figure 4 (a) is (Rca-Raa) / Raa × 100, Figure 4 (b) is (Rcc - Rca) / Rca × 100, where Raa represents the reflectivity of the device when both 2.1 and 2.2 are amorphous, Rca Represents 2.1 as the crystalline state, 2.2 as the reflectivity of the device in the amorphous state, and Rcc represents the reflectance of the device when both 2.1 and 2.2 are crystalline. As can be seen from the figure, by selecting the thickness of the different isolation layers 4, the reflectance of a specific wavelength can be greatly modulated.
图1(b)的显示器件能够制备得到均匀的颜色，同时也可以转换得到高对比的颜色，或者通过改变反射率得到更暗或更亮的颜色。在一种形式 的显示器中，许多如图1(b)的结构互相接壤形成阵列，并且每个结构能够被单独控制施加电压或者激光，组成整个显示器中的一个像素点。在另外一种形式的显示器中，每个像素点由几个如图1(b)的结构(称为子像素)互相接壤组成，但是像素点中的每个子像素隔离层4的厚度均不同。通过这种方法像素点中的每个子像素能够在三种颜色之间转换，像素点能展现出更宽泛的颜色而不仅仅在三种颜色之间转换。像素点中不同厚度的子像素个数可以为3个或者更多。The display device of Fig. 1(b) is capable of producing a uniform color, and can also be converted to a high contrast color, or by changing the reflectance to obtain a darker or brighter color. In one form In the display, many of the structures as shown in Figure 1(b) are interconnected to form an array, and each structure can be individually controlled to apply a voltage or laser to form a pixel in the entire display. In another form of display, each pixel is composed of several structures (referred to as sub-pixels) as shown in FIG. 1(b), but each sub-pixel isolation layer 4 in the pixel has a different thickness. In this way, each sub-pixel in a pixel can be converted between three colors, and the pixel can exhibit a wider color than just switching between the three colors. The number of sub-pixels of different thicknesses in the pixel may be three or more.
另外一种增强的实施例为相变材料层2.1和2.2不需要在完全晶态和完全非晶态之间转换。通过比如20％晶化，40％晶化等可以得到混合相。部分晶化可以简单的通过在转换过程中限制电流的最大值或者激光功率来实现。完全非晶和完全晶化间的材料的折射率取决于部分晶化的程度。典型地可以得到16和64个混合相之间的相态。并且在合适的控制下可以得到更多的相，如1024个。Another enhanced embodiment is that the phase change material layers 2.1 and 2.2 do not need to be switched between fully crystalline and fully amorphous. The mixed phase can be obtained by, for example, 20% crystallization, 40% crystallization, or the like. Partial crystallization can be achieved simply by limiting the maximum current or laser power during the conversion process. The refractive index of a material between completely amorphous and fully crystallized depends on the degree of partial crystallization. A phase between 16 and 64 mixed phases is typically obtained. And under the appropriate control, you can get more phases, such as 1024.
图5是根据本发明一个实施例的显示器件电极阵列的俯视图。衬底10用来作为每个像素的反射层。12.1，12.2，12.3，……，12.n是水平电极。这些电极组成了隔离层4。固态的相变层排成图案沉积在隔离层4上面。接下来制备一系列垂直电极11.1，11.2，11.3，11.4，……，11.n。反射层和固态相变层只需要在水平和垂直电极的交叉点存在。所有的制备，沉积和图案化都可以使用已知的光刻技术。Figure 5 is a top plan view of an array of display device electrodes in accordance with one embodiment of the present invention. The substrate 10 is used as a reflective layer for each pixel. 12.1, 12.2, 12.3, ..., 12.n are horizontal electrodes. These electrodes constitute the isolation layer 4. A solid phase change layer is patterned in a pattern on top of the isolation layer 4. Next, a series of vertical electrodes 11.1, 11.2, 11.3, 11.4, ..., 11.n were prepared. The reflective layer and the solid phase change layer need only exist at the intersection of the horizontal and vertical electrodes. All fabrication, deposition and patterning can be performed using known photolithographic techniques.
每个水平和垂直电极的交叉点组成了如图1(b)所示的堆叠结构。在制备过程中，隔离层/水平(底)电极的厚度分别不同，以至于每个像素点可以表现出如图2到4所示的不同的颜色范围。通过在水平和垂直电极上施加合适的电压，像素中的相变材料可以按预期转变。然而，阵列中别的像素没有受到影响，所以像素的寻址很简单。The intersection of each of the horizontal and vertical electrodes constitutes a stacked structure as shown in Fig. 1(b). In the preparation process, the thickness of the spacer/horizontal (bottom) electrodes are different, respectively, so that each pixel point can exhibit different color ranges as shown in FIGS. 2 to 4. By applying a suitable voltage across the horizontal and vertical electrodes, the phase change material in the pixel can be converted as desired. However, the other pixels in the array are not affected, so the addressing of the pixels is simple.
虽然在某些实施例中使用ITO作为优选的透明电极，但这仅仅是个例子，其它合适的材料，例如碳纳米管，或者超薄金属，如银等也可以。 Although ITO is used as the preferred transparent electrode in some embodiments, this is merely an example, and other suitable materials such as carbon nanotubes, or ultra-thin metals such as silver may also be used.
在前面描述的实施例中，Sb2Te3和GeTe作为相变材料层2.1和2.2，但是这不是必须的，许多其它的合适材料也可以使用，包括硫系化合物及其合金或过渡金属氧化物，包括但不限于：GeTe，SbTe,BiTe,InSb,InSe,GeSb,SbSe,GaSb,GaSb,GeSbTe，AgInSbTe,InSbTe,AgSbTe,VO,NbO。这些材料不同的化学计量比也是可以的，例如GexSbyTez；另外一种合适的材料是Ag2In4Sb76Te17(AIST)。此外，材料可以包含一种或多种掺杂，如C或N。In the previously described embodiments, Sb 2 Te 3 and GeTe are used as the phase change material layers 2.1 and 2.2, but this is not essential, and many other suitable materials may be used, including sulfur compounds and their alloys or transition metal oxides. Including, but not limited to, GeTe, SbTe, BiTe, InSb, InSe, GeSb, SbSe, GaSb, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, VO, NbO. Different stoichiometric ratios of these materials are also possible, such as Ge x Sb y Te z ; another suitable material is Ag 2 In 4 Sb 76 Te 17 (AIST). Additionally, the material may comprise one or more dopants such as C or N.
转变机制不仅仅局限于施加电流脉冲诱导加热，其它任何电磁场诱导的加热都可以，例如激光脉冲，或者在与相变材料热接触的相邻层使用电阻加热的方法诱导加热也是可以的。The transformation mechanism is not limited to the application of current pulse induced heating, any other electromagnetic field induced heating, such as a laser pulse, or induction heating using an electrical resistance heating method in an adjacent layer in thermal contact with the phase change material.
本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。 Those skilled in the art will appreciate that the above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the present invention, All should be included in the scope of protection of the present invention.

Claims (13)

  1. 一种基于相变材料的显示器件，包括一系列像素点，其特征在于，每个像素点包括沉积在衬底上的反射层、沉积在所述反射层上的隔离层、沉积在所述隔离层上的固态相变层和沉积在所述固态相变层上的覆盖层；A phase change material-based display device comprising a series of pixel points, wherein each pixel dot comprises a reflective layer deposited on a substrate, an isolation layer deposited on the reflective layer, and deposited in the isolation a solid phase change layer on the layer and a cover layer deposited on the solid phase change layer;
    所述反射层在可见光范围内拥有80％以上的反射率，用于提供背面反射；所述隔离层用于调节整个器件的反射率；所述固态相变层用于在电压或者激光驱动下使像素点的颜色进行转换；所述覆盖层用于接收外部施加的电压；在电压或者激光驱动下所述固态相变层可以在晶态和非晶态之间可逆转变，引起相变材料折射率的变化，从而使得每个像素点的颜色发生改变。The reflective layer has a reflectivity of more than 80% in the visible range for providing back reflection; the isolation layer is used to adjust the reflectivity of the entire device; the solid phase change layer is used to drive under voltage or laser The color of the pixel is converted; the cover layer is for receiving an externally applied voltage; the solid phase change layer can be reversibly transformed between a crystalline state and an amorphous state under voltage or laser driving, causing a refractive index of the phase change material The change so that the color of each pixel changes.
  2. 如权利要求1所述的显示器件，其特征在于，所述隔离层的厚度可以根据显示需要的反射率值来确定。The display device according to claim 1, wherein the thickness of the spacer layer can be determined according to a reflectance value required for display.
  3. 如权利要求1或2所述的显示器件，其特征在于，所述固态相变层的折射率在外加电压或激光诱导下在晶态和非晶态之间转变。A display device according to claim 1 or 2, wherein the refractive index of said solid phase change layer is changed between a crystalline state and an amorphous state under an applied voltage or laser induced.
  4. 如权利要求1-3任一项所述的显示器件，其特征在于，所述固态相变层包括一层或多层不同的相变材料，通过分别对每层相变材料的状态进行单独控制使得所述显示器件呈现多种颜色。The display device according to any one of claims 1 to 3, wherein the solid phase change layer comprises one or more layers of different phase change materials, and the state of each phase change material is separately controlled by separately The display device is rendered in a plurality of colors.
  5. 如权利要求1-4所述的显示器件，其特征在于，所述的相变材料包括下列硫系化合物及其合金或过渡金属氧化物，包括但不限于：GeTe，SbTe,BiTe,InSb,InSe,GeSb,SbSe,GaSb,GaSb,GeSbTe，AgInSbTe,InSbTe,AgSbTe,VO,NbO。The display device according to any one of claims 1 to 4, wherein said phase change material comprises the following sulfur-based compound and alloy or transition metal oxide thereof, including but not limited to: GeTe, SbTe, BiTe, InSb, InSe , GeSb, SbSe, GaSb, GaSb, GeSbTe, AgInSbTe, InSbTe, AgSbTe, VO, NbO.
  6. 如权利要求4或5所述的显示器件，其特征在于，所述固态相变层的材料还包含至少一种掺杂剂。A display device according to claim 4 or 5, wherein the material of the solid phase change layer further comprises at least one dopant.
  7. 如权利要求4或5所述的显示器件，其特征在于，所述固态相变层包括两层，两层的材料分别为GeTe和Sb2Te3。 The display device according to claim 4 or 5, wherein the solid phase change layer comprises two layers, and the materials of the two layers are GeTe and Sb 2 Te 3 , respectively .
  8. 如权利要求1-7任一项所述的显示器件，其特征在于，所述固态相变层的厚度小于60nm。The display device according to any one of claims 1 to 7, wherein the solid phase change layer has a thickness of less than 60 nm.
  9. 如权利要求8所述的显示器件，其特征在于，所述固态相变层的厚度小于10nm。The display device of claim 8 wherein said solid phase change layer has a thickness of less than 10 nm.
  10. 如权利要求1-9任一项所述的显示器件，其特征在于，所述覆盖层和所述隔离层对光透明。The display device according to any one of claims 1 to 9, wherein the cover layer and the spacer layer are transparent to light.
  11. 如权利要求1-10任一项所述的显示器件，其特征在于，所述覆盖层和隔离层的材料为透明电极，如铟锡氧化物。The display device according to any one of claims 1 to 10, wherein the material of the cover layer and the isolation layer is a transparent electrode such as indium tin oxide.
  12. 如权利要求10或11所述的显示器件，其特征在于，所述隔离层厚度范围为10nm-300nm。The display device according to claim 10 or 11, wherein the spacer layer has a thickness ranging from 10 nm to 300 nm.
  13. 如权利要求1-12任一项所述的显示器件，其特征在于，所述显示器件包括一系列排成阵列的像素点，通过空间上的结构堆叠形成显示阵列。 The display device according to any one of claims 1 to 12, wherein the display device comprises a series of pixel dots arranged in an array, and the display array is formed by spatially stacking the structures.
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