CN111736245B

CN111736245B - Plasmon color filter

Info

Publication number: CN111736245B
Application number: CN202010748149.3A
Authority: CN
Inventors: 郑梦洁; 董君
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2022-01-28
Anticipated expiration: 2040-07-30
Also published as: CN111736245A

Abstract

A plasmon color filter relates to the technical field of color filters and comprises a plurality of color filter units, wherein each color filter unit comprises a reflecting layer, an intermediate layer and a resonator which are longitudinally and sequentially stacked, and the resonator is made of a material with anomalous dispersion optical characteristics in a visible light waveband. When the incident light in the visible light wave band irradiates the structural system from one side of the resonator, energy is highly localized in the intermediate layer (namely the gap between the resonator and the reflecting layer), and gap plasmon resonance is excited, so that the selective absorption of a specific wave band in the visible light wave band is realized. The anomalous dispersion properties of the resonator body enhance the gap plasmon resonance of such a structural system, so that a more drastic response to changes in the gap between the resonator body and the reflective layer, i.e. the same scale of gap change, can result in a spectral modulation of greater amplitude in the visible range, thereby increasing spectral tuning sensitivity.

Description

Plasmon color filter

Technical Field

The present invention relates to the field of color filter technology.

Background

The color filter based on the artificial microcosmic ordered structure can correspondingly absorb and reflect light through interference, diffraction and the like of the light, thereby realizing the filtration of a specific light wave band, and being widely applied to the fields of anti-counterfeiting, display, information storage and the like. In recent years, the color filter utilizing the sub-wavelength structure surface plasmon effect can break through the traditional optical diffraction limit, realize the control of light on the nanometer scale and obtain higher optical resolution, thereby having good application prospect in the field with ultrahigh resolution display requirement.

In the prior art, a color filter based on the surface plasmon effect mainly has structural forms such as a (quasi) metal/medium nano resonator, a (quasi) metal-medium- (quasi) metal composite structure and the like, the resonator is usually made of a material with normal dispersion optical characteristics in a visible light band, and the sensitivity of spectral tuning is low.

Disclosure of Invention

In view of the above, the present invention provides a plasmon color filter having high sensitivity of spectral tuning.

In order to achieve the above object, the present invention provides the following technical solutions.

1. A plasmon color filter includes a plurality of color filter units, each of which includes a reflective layer, an intermediate layer, and a resonator body, which are sequentially stacked in a longitudinal direction, the resonator body being made of a material having an optical characteristic of anomalous dispersion in a visible light band.

The resonator, the intermediate layer and the reflecting layer form a structural system supporting gap plasmons, and the gap plasmon resonance in the open system can be understood as surface plasmons of a closed planar multilayer system limited by a specific quantized resonant wave vector. When the incident light of the visible light wave band irradiates the structural system from one side of the resonator, the energy is highly localized in the middle layer (namely the gap between the resonator and the reflecting layer), gap plasmon resonance is excited, so that selective absorption of a specific wave band in the visible light wave band is realized, finally, the rest light is reflected, and the reflected light forms colors which can be recognized by human eyes, so that the purpose of color filtering is achieved.

The resonator body is made of a material having anomalous dispersion optical characteristics in the visible light band, and the anomalous dispersion property of the resonator body can enhance the gap plasmon resonance of the structure system, so that the response to the change of the thickness of the intermediate layer (namely, the gap between the resonator body and the reflecting layer) is more severe, namely, the same scale of gap change can cause spectral modulation with larger amplitude in the visible light range, thereby improving the spectral tuning sensitivity.

2. The plasmon filter according to claim 1, wherein the resonator is made of germanium.

3. The plasmon color filter of claim 1 wherein the intermediate layer is made of a material having a controllably variable dimension such that the longitudinal thickness of the intermediate layer is controllably variable. When the longitudinal thickness of the middle layer (namely the gap between the resonator and the reflecting layer) is changed, the position of a gap plasmon resonance absorption peak (a selectively absorbed waveband) can be changed, so that the spectrum is subjected to red shift or blue shift, and the purpose of spectrum dynamic tuning (namely dynamic color tuning) is realized.

4. The plasmon color filter according to claim 3, further comprising an electric control device, wherein the intermediate layer is made of an organic molecular material of a disulfide-based modifier of PEG or a cadmium sulfide piezoelectric material, and the electric control device is connected to the intermediate layer so as to change the thickness of the intermediate layer in an electric control manner. The organic molecular material of the disulfide-based modification of PEG, cadmium sulfide piezoelectric material, are all known materials with controllable size change.

5. The plasmon filter according to claim 1, wherein the cross section of the resonator is circular. The resonator body has no sharp-angle structure, plasmons formed on the surface of the structure can be more uniform, and the resonator body can be processed and manufactured more easily.

6. The plasmon filter according to claim 5, wherein the plurality of filter units are arranged in a plurality of rows along the X direction and arranged in a plurality of rows along the Y direction, the ratio of the period of any two adjacent filter units in each row to the diameter of the cross section of the resonator of the two filter units is 2:1,

said period being the distance between the centres of said cross-sections of the resonators of two adjacent colour filter units,

the X direction and the Y direction are mutually vertical, a plane determined by the X direction and the Y direction is taken as a reference plane,

the cross-section is a section taken by a reference plane or a plane parallel to the reference plane.

The color filter units are arranged too densely, and adjacent color filter units can be coupled, so that a higher mode is introduced and the spectrum is red-shifted; if the arrangement is too thin, the color efficiency is too low and the color is too light.

7. The plasmon color filter according to claim 5 wherein the diameter of the cross section is 40nm or more and 100nm or less. This size range allows plasmon resonance absorption peak positions in the visible light range. Different cross section diameters of the resonator can change the plasmon resonance peak position, the cross section diameter of the resonator is fixed after the resonator is manufactured by adopting a micro-nano processing technology, and a full-color image can be realized by utilizing the static framework, namely, a color filter unit array with different periods and different cross section diameters of the resonator corresponding to different colors is filled in each pixel in the full-color image.

8. The plasmon color filter according to claim 7, wherein the longitudinal thickness of the resonator is 60 nm. The change in the longitudinal height of the resonator affects the efficiency of reflected light and thus the brightness of the color without changing the plasmon resonance absorption peak position.

9. The plasmon color filter according to claim 1 further comprising a light-transmissive substrate, wherein the substrate, the resonator, the intermediate layer, and the reflective layer are sequentially stacked in each color filter unit.

In actual manufacturing and application, in order to achieve a larger degree of color gamut expansion, an easily oxidized silver material is generally used as the reflective layer, and in this case, a reverse configuration (i.e., a structure in which the substrate, the resonator, the intermediate layer, and the reflective layer are sequentially stacked) is adopted. The reflecting layer in the reverse configuration is manufactured finally, and because the manufacturing of the reflecting layer is carried out in a vacuum environment, the contact surface of the reflecting layer and the middle layer is formed in the vacuum environment, the phenomenon that the reflecting layer in contact with the middle layer is oxidized to change the gap between the resonator and the reflecting layer is avoided, and the accuracy of color filtering is ensured.

10. The plasmon color filter according to claim 1, wherein the reflective layers of all the color filter units are integrated. The processing is easy.

11. The plasmon color filter according to claim 1, wherein the intermediate layers of all the color filter units are integrated. The processing is easy.

Drawings

FIG. 1 is a schematic diagram of a plasmon color filter according to the present invention;

FIG. 2 is a schematic diagram of a longitudinal cross-section along A-A in FIG. 1 of one embodiment of a plasmonic color filter of the present invention;

fig. 3 is a schematic structural view of a longitudinal section along a-a direction in fig. 1 of another embodiment of the plasmonic color filter of the present invention.

The reference numerals include:

color filter unit 1, reflection layer 11, intermediate layer 12, resonator 13, substrate 2.

Detailed Description

The present invention will be described in detail with reference to specific examples.

As shown in fig. 1, the plasmon color filter of the present embodiment includes a plurality of color filter units 1, and the color filter units 1 are arranged in a plurality of rows in the X-axis direction and in a plurality of columns in the Y-axis direction, and the X-axis and the Y-axis are perpendicular to each other. As shown in fig. 2, each color filter unit 1 includes a reflective layer 11, an intermediate layer 12, and a resonator 13, and the reflective layer 11, the intermediate layer 12, and the resonator 13 are sequentially stacked in a longitudinal direction, i.e., a Z-axis direction, to form a three-dimensional rectangular coordinate system with an X-axis and a Y-axis, to form a metal-dielectric-metal-like composite structure. The resonator body 13 is made of a material having an anomalous dispersion optical characteristic in the visible light band, and in the present embodiment, the resonator body 13 is made of germanium, and the anomalous dispersion optical characteristic of the resonator body 13 in the visible light band enhances the gap plasmon resonance of the structural system of the color filter unit 1, so that a response to a change in the thickness of the intermediate layer 12 (i.e., the gap between the resonator body 13 and the reflective layer 11) is more severe, that is, the same scale as the gap change, resulting in a spectral modulation of a larger amplitude in the visible light range, thereby improving the spectral tuning sensitivity.

In order to realize dynamic tuning of spectrum and dynamic color change, the intermediate layer 12 is made of a material with controllable size, such as organic molecular material of disulfide-based modified PEG or cadmium sulfide piezoelectric material, which can change its size by an electric control method, so as to change the longitudinal thickness of the intermediate layer 12, and therefore an electric control device (not shown) is further provided to control the longitudinal thickness of the intermediate layer 12. When the longitudinal thickness of the intermediate layer 12 (i.e. the gap between the resonator 13 and the reflective layer 11) is changed, the position of the gap plasmon resonance absorption peak (the selectively absorbed waveband) is changed, so that the spectrum is red-shifted or blue-shifted, and the purpose of dynamic tuning (i.e. dynamic color tuning) of the spectrum is achieved.

In combination with the resonator body 13 made of a material having anomalous dispersion optical characteristics in the visible light band, the longitudinal thickness variation of the intermediate layer 12 in the same dimension can cause spectral modulation of a larger amplitude in the visible light range, thereby improving spectral tuning sensitivity. In other words, a greater range of color variation can be achieved with the same scale of longitudinal thickness variation of the intermediate layer 12.

As shown in fig. 2, in the present embodiment, the reflective layers 11 of all the color filter units 1 are integrated, and the reflective layer 11 of each color filter unit 1 is a part of this integrated body; the intermediate layers 12 of all color filter units 1 are also integral, the intermediate layer 12 of each color filter unit 1 being a part of this whole.

As shown in fig. 1, the cross-section of the resonator body 13 is circular. In this document, a plane defined by both the X axis and the Y axis is a reference plane, and a cross section taken by the reference plane or a plane parallel to the reference plane is a cross section. The resonator 13 and the projected area of the resonator 13 in the Z-axis direction (i.e., the portion shown by the dotted line in fig. 2 and 3) of the intermediate layer 12 and the reflective layer 11 constitute one color filter unit 1, the ratio of the period of any two adjacent color filter units 1 to the diameter of the resonator 13 in each row arranged in the X-axis direction is 2:1, the period is the distance between the centers of the cross sections of the resonators 13 of the two adjacent color filter units 1, and L1 and L2 are periods in fig. 1, in conjunction with fig. 1, L1: d1 ═ 2:1, L1: d2 ═ 2:1, L1: d3 ═ 2:1, L1: d4 ═ 2:1, L2: d1 ═ 2:1, L2: d3 ═ 2:1, L2: d2 ═ 2:1, L2: d4 ═ 2: 1. As shown in FIG. 1, in the present embodiment, the diameter (D1, D2, D3, D4) of the cross section of the resonator 13 is 40nm or less and 100nm or less, and the longitudinal thickness H1 of the resonator 13 is 60 nm. The color filter units 1 are arranged too densely, and the adjacent color filter units 1 may be coupled, so that a higher mode is introduced and the spectrum is red-shifted; if the arrangement is too thin, the color efficiency is too low and the color is too light.

As shown in fig. 2, in the process of processing the plasmon color filter of this embodiment, a substrate 2 is required, and then a reflective layer 11 is formed on the substrate 2, where the reflective layer 11 is usually made of metal, such as high reflective materials like gold, silver, and aluminum, the longitudinal thickness of the reflective layer 11 is about 100nm, and the longitudinal thicknesses of the reflective layers 11 made of different materials are different, so as to satisfy the requirement that the transmittance of light is zero. The thickness of the reflecting layer 11 is nanometer, and it is generally manufactured on the substrate 2 by vacuum coating process, and after the reflecting layer 11 is manufactured, the intermediate layer 12 and the resonator 13 are manufactured. The resonator 13 is manufactured by a micro-nano processing technology.

However, after the manufacturing process, in the process of taking the substrate 2 and the reflective layer 11 out of the vacuum environment and then manufacturing the intermediate layer 12, since the substrate is taken out of the vacuum environment, the surface exposed in the air of the easily oxidized material, such as silver, is naturally oxidized, so that the contact surface between the reflective layer 11 and the intermediate layer 12 is oxidized to form an oxide film, which becomes a medium and becomes a part of the intermediate layer 12, thereby changing the gap between the resonator 13 and the reflective layer 11, and affecting the accuracy of the color filtering.

As shown in fig. 3, in another embodiment, another structure is provided, in which the color filter unit 1 is inverted compared to the embodiment of fig. 2. In the embodiment of fig. 2, the resonator body 13, the intermediate layer 12, the reflective layer 11, and the substrate 2 are stacked in this order from the top in the drawing in each color filter unit 1, and in the embodiment of fig. 3, the reflective layer 11, the intermediate layer 12, the resonator body 13, and the substrate 2. Thus, the reflecting layer 11 is finally formed in the manufacturing process, and the reflecting layer 11 is directly formed on the surface of the intermediate layer 12 in a vacuum environment, so that the phenomenon that the reflecting layer 11 in contact with the intermediate layer 12 is oxidized to change the gap between the resonator 13 and the reflecting layer 11 can be avoided, and the accuracy of color filtering is ensured.

In this document, the X-axis direction, the Y-axis direction, and the Z-axis direction all include positive and negative directions of the corresponding axial directions. The X-axis direction is the X direction, the Y-axis direction is the Y direction, the X direction and the Y direction can be designed according to actual conditions, and the X direction and the Y direction can not be perpendicular to each other. The arrangement of the color filter units 1 is not limited to the orthogonal arrangement in the present embodiment, and may be an arrangement such as a regular hexagonal lattice structure.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. The plasmon color filter comprises a plurality of color filter units, and is characterized in that each color filter unit comprises a reflecting layer, an intermediate layer and a resonator which are longitudinally and sequentially laminated, and the resonator is made of a material with anomalous dispersion optical characteristics in a visible light wave band.

2. The plasmonic color filter of claim 1, wherein the resonator body is made of germanium.

3. The plasmonic color filter of claim 1 wherein the intermediate layer is made of a material that is controllably variable in size such that the longitudinal thickness of the intermediate layer is controllably variable.

4. The plasmonic color filter of claim 3, further comprising an electrical control device, the intermediate layer being made of an organic molecular material of a disulfide-based modification of PEG or a cadmium sulfide piezoelectric material, the electrical control device being coupled to the intermediate layer to electrically control a thickness of the intermediate layer.

5. The plasmonic color filter of claim 1 wherein the cross section of the resonator body is circular.

6. The plasmonic color filter of claim 5, wherein a plurality of the color filter units are arranged in a plurality of rows in an X direction and in a plurality of columns in a Y direction, a ratio of a period of any two adjacent color filter units in each row to a diameter of the cross section of the resonator of the two color filter units is 2:1, a ratio of a period of any two adjacent color filter units in each column to a diameter of the cross section of the resonator of the two color filter units is 2:1,

the X direction and the Y direction are mutually perpendicular, a plane determined by the X direction and the Y direction is a reference plane, and the cross section is a section cut by the reference plane or a plane parallel to the reference plane.

7. The plasmonic color filter of claim 5, wherein the diameter of the cross section is greater than or equal to 40nm and less than or equal to 100 nm.

8. The plasmonic filter of claim 7, wherein the longitudinal thickness of the resonator is 60 nm.

9. The plasmonic color filter of claim 1, further comprising a light-transmissive substrate, wherein in each color filter unit, the substrate, the resonator, the intermediate layer, and the reflective layer are sequentially stacked.

10. The plasmonic filter of claim 1, wherein the reflective layer of all filter cells is integral.

11. The plasmonic filter of claim 1, wherein the intermediate layers of all filter cells are integral.