A tunable dual-channel filter in the visible light band

Abstract

This invention discloses a visible light band adjustable dual-channel filter, comprising a visible light transparent substrate and a dielectric filter. The dielectric filter consists of two sets of dielectric films, denoted as a first dielectric film set A and a second dielectric film set B. The first dielectric film set A controls the position of the long-wavelength channel, and the second dielectric film set B controls the position of the short-wavelength channel. The position of the dual channels can be arbitrarily adjusted by changing the thickness of the dielectric material layer in the first dielectric film set A and the second dielectric film set B, achieving a dual-channel filtering effect in the visible light band. This visible light band adjustable dual-channel filter has high transmittance of the channel windows, which can reduce the loss of the target wavelength. At the same time, the half-width at half-maximum (WHM) of the filter channels can meet the filtering requirements for color purity in color displays. This visible light band adjustable dual-channel filter can be directly bonded to a color display, resulting in high color purity and high stability.

Description

Technical Field

[0001] This invention relates to the field of photonic crystal filters, and in particular to a tunable dual-channel filter in the visible light band. Background Technology

[0002] In recent years, the demand for high-quality color displays has gradually increased, while higher requirements have been placed on the color purity and color stability of color displays. To achieve this, the width of the emission peak of the pixel light source in the color display can be reduced, thereby improving color purity. For example, a color filter can be added during the fabrication of a liquid crystal display to filter the light. Chinese patent (CN112764148A) discloses a method for fabricating a single-channel pixel filter on the pixel unit of a color display to obtain high-quality color display and display effect. However, based on this single-channel filter method, filters for different color bands need to be fabricated separately during color display, resulting in complex processing technology.

[0003] Dual-channel or multi-channel filters would be a good solution, not only satisfying multi-color filtering but also reducing processing workload. Chinese patent (CN113625372A) discloses a method for obtaining a dual-channel filter by inserting graphene into a photonic crystal. However, the dual-channel filter structure prepared by this method is AGBGAGBGBGBGAGBGA, where AB are high and low refractive index material layers with different refractive indices, and G is the graphene layer. This requires multiple graphene preparations, making the process cumbersome, and the preparation of large-size graphene is relatively difficult.

[0004] Chinese patent (CN113625372A) discloses a one-dimensional photonic crystal dual-channel visible light narrowband filter. However, this method of achieving a dual-channel filter by adjusting the thickness of the defect layer means that the positions of the two channels are not independently adjustable; in short, the filtering position is limited and not very flexible. Summary of the Invention

[0005] The purpose of this invention is to provide a visible light band adjustable dual-channel filter, so that the channels of the dual-channel filter are adjustable within the visible light band.

[0006] The objective of this invention is achieved as follows: A visible light band tunable dual-channel filter is characterized by comprising a visible light transparent substrate and a dielectric filter, wherein the dual channels of the dielectric filter are positioned between 400 nm and 700 nm, the transmittance of the dual channels of the dielectric filter is >60%, and the dielectric filter is composed of two sets of dielectric films, denoted as the first dielectric film set A and the second dielectric film set B, wherein the first dielectric film set A controls the position of the long wavelength channel, and the second dielectric film set B controls the position of the short wavelength channel. The first dielectric film group A has the following characteristics: the transmittance of the peak value λ1 of the filter channel of the first dielectric film group A is greater than 60%; the full width at half maximum (FWHM) of the filter channel of the first dielectric film group A is less than 30 nm; and the wavelength range on both sides of the peak value λ1 of the filter channel of the first dielectric film group A with reflectance greater than 90% is λ. 11 ~λ 12 and λ 13 ~λ 14 , where: λ 11 <λ 12 <λ1<λ 13 <λ 14 , λ 12 -λ 11 >30 nm, λ 14 -λ 13 >30 nm; The second dielectric film group B has the following characteristics: the transmittance of the peak value λ2 of the filter channel of the second dielectric film group B is greater than 60%; the full width at half maximum (FWHM) of the filter channel of the second dielectric film group B is less than 30 nm; and the wavelength range in which the reflectance on both sides of the peak value λ2 of the filter channel of the second dielectric film group B is greater than 90% is λ. 21 ~λ 22 and λ 23 ~λ 24 , where: λ 21 <λ 22 <λ2<λ 23 <λ 24 , λ 22 -λ 21 >30 nm, λ 24 -λ 23 >30 nm; λ of the first dielectric membrane group A 11 λ greater than that of the second dielectric film group B 23 Meanwhile, the λ of the second dielectric membrane group B 24 λ is less than that of the first dielectric film group A 12 .

[0007] Preferably, the structure of the first dielectric membrane group A is (L1H1). k1 (H1L1) k1 L1 is the first low-refractive-index dielectric layer, H1 is the first high-refractive-index dielectric layer, and k1 is the period number; the structure of the second dielectric film group B is H2 (L2H2). k2 (H2L2) k2 H2 and L2 are the second low-refractive-index dielectric layers, H2 is the second high-refractive-index dielectric layer, and k2 is the period number.

[0008] Preferably, the position of the long-wavelength channel is controlled by changing the thickness of the dielectric material layer in the first dielectric film group A, and the position of the short-wavelength channel is controlled by changing the thickness of the dielectric material layer in the second dielectric film group B.

[0009] Preferably, the low-refractive-index dielectric material layer is SiO2; the high-refractive-index dielectric material layer is SiN. x Or TiO2.

[0010] This invention provides a tunable dual-channel filter in the visible light band, which has the following advantages: 1. The dual-channel filter has adjustable channels. The channel position of the visible light dual-channel filter of the present invention can be adjusted by changing the thickness of the dielectric material layer in the dielectric film group, thereby achieving the effect of dual-channel filtering in the visible light band; 2. There is no dependency between the positions of the two channel windows, and the positions of the two channels can be freely adjusted; therefore, the dual-channel filter of this invention with no linear relationship breaks through the limitation of regular filtering of previous multi-channel filters. 3. The dual-channel filter has high transmittance and narrow half-width at half-maximum (WHM) of its channel window. The visible light band adjustable dual-channel filter of this invention has high transmittance of its channel window, which can reduce the loss of the target wavelength. At the same time, the narrow WHM of the filter channel can meet the filtering requirements for color purity in color display. 4. The first dielectric film group A controls the position of the long wavelength channel, and the second dielectric film group B controls the position of the short wavelength channel; 5. This type of visible light band adjustable dual-channel filter can be directly bonded to color displays, resulting in high color purity and stability. 6. The dual-channel filter is easy to use. The visible light band tunable dual-channel filter of this invention is fabricated on a visible light transparent substrate and can be directly bonded to a display to achieve the purpose of color display. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a visible light band tunable dual-channel filter. Figure 2 This is a simulated reflectance spectrum of a tunable dual-channel filter in the visible light band; Figure 3 The reflection spectrum of a visible light band tunable dual-channel filter in Example 2; Figure 4 The test spectrum of the halogen lamp; Figure 5 The test spectrum was obtained by applying the filter membrane prepared in this invention to a halogen lamp; Figure 6 The reflection spectrum of a visible light band tunable dual-channel filter in Example 3; Figure 7 This is the reflection spectrum of a visible light band tunable dual-channel filter in Example 4; Explanation of reference numerals in the attached drawings: substrate 000, first low refractive index dielectric layer 101, first high refractive index dielectric layer 102, second low refractive index dielectric layer 201, second high refractive index dielectric layer 202. Implementation

[0012] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with specific embodiments. Example

[0013] A visible light band tunable dual-channel filter, with the structure as follows: Figure 1 As shown, substrate 000 is sapphire. The structure of the first dielectric film group A is (L1H1). k1 (H1L1) k1 L1 is the first low-refractive-index dielectric layer 101, H1 is the second high-refractive-index dielectric layer 102, and k1 is the period number. The first low-refractive-index dielectric layer 101 is made of SiO2 with a thickness of 107 nm, and the first high-refractive-index dielectric layer 102 is made of SiN. x The thickness is 78 nm, and the period number k1 is 6. The structure of the second dielectric film group B is H2(L2H2). k2 (H2L2) k2 H2 and L2 represent the second low-refractive-index dielectric layer 201, H2 represents the second high-refractive-index dielectric layer 202, and k2 is the period number. The second low-refractive-index dielectric layer 201 is made of SiO2 with a thickness of 89 nm, and the second high-refractive-index dielectric layer 202 is made of SiN. x The thickness is 65 nm and the number of periods K2 is 5.

[0014] Figure 2 The image shows the reflectance spectra of the first dielectric film group A and the second dielectric film group B. The peak value λ1 of the filter channel in the first dielectric film group A is 635 nm, with a transmittance close to 100%. The full width at half maximum (FWHM) of the filter channel in the first dielectric film group A is 11 nm. The wavelengths with reflectance greater than 90% on either side of the peak value of 635 nm are 556 nm–618 nm and 653 nm–740 nm. The peak value of the filter channel in the second dielectric film group B is 532 nm, with a transmittance close to 90%. The FWHM of the filter channel in the second dielectric film group B is 4 nm. The wavelengths with reflectance greater than 90% on either side of the peak value of 532 nm in the second dielectric film group B are 467 nm–525 nm and 538 nm–613 nm.

[0015] The reflectance spectrum of the visible light band tunable dual-channel filter obtained by combining the first dielectric film group A and the second dielectric film group B is as follows: Figure 2 As shown, the tunable dual-channel filter in the visible light band operates at 532 nm and 635 nm. The transmittance of the filter channel at 635 nm is close to 100%, and the full width at half maximum (FWHM) of the filter channel is 12 nm; the transmittance of the filter channel at 532 nm is close to 86%, and the FWHM of the filter channel is 4 nm. Example

[0016] A visible light band tunable dual-channel filter, with the structure as follows: Figure 1 As shown, substrate 000 is a quartz sheet. The structure of the first dielectric film group A is (L1H1). k1 (H1L1) k1 L1 represents the first low-refractive-index dielectric layer 101, H1 represents the first high-refractive-index dielectric layer 102, and k1 represents the period number. The first low-refractive-index dielectric layer 101 is made of SiO2 with a thickness of 106.3 nm, and the first high-refractive-index dielectric layer 102 is made of SiN. x The thickness is 77.7 nm, and the period number k1 is 6. The structure of the second dielectric film group B is H2 (L2H2). k2 (H2L2) k2 H2 and L2 represent the second low-refractive-index dielectric layer 201, H2 represents the second high-refractive-index dielectric layer 202, and k2 is the period number. The second low-refractive-index dielectric layer 201 is made of SiO2 with a thickness of 88.4 nm, and the second high-refractive-index dielectric layer 202 is made of SiN. x The thickness is 64.7 nm, and the period number K2 is 5.

[0017] Figure 3 The reflectance spectrum of the prepared tunable dual-channel filter in the visible light band is shown. The transmittance of the 625 nm filter channel is 88%, and the full width at half maximum (FWHM) of the 625 nm filter channel is 9 nm. The transmittance of the 520 nm filter channel is 75%, and the FWHM of the 520 nm filter channel is 10 nm. The reflectance is greater than 90% in the wavelength ranges of 467 nm to 514 nm, 537 nm to 608 nm, and 645 nm to 696 nm.

[0018] Figure 4 It is the emission spectrum of a halogen lamp. Figure 5 The spectrum collected after the halogen lamp passes through the tunable dual-channel filter in the visible light band shows that the halogen lamp spectrum has narrow green and red light peaks with half-widths of 14 nm and 10 nm, respectively, indicating that the tunable dual-channel filter in the visible light band can effectively filter light. Example

[0019] A visible light band tunable dual-channel filter, with the structure as follows: Figure 1 As shown, substrate 000 is a quartz sheet. The structure of the first dielectric film group A is (L1H1). k1 (H1L1) k1 L1 is the first low-refractive-index dielectric layer 101, H1 is the first high-refractive-index dielectric layer 102, and k1 is the period number. The first low-refractive-index dielectric layer 101 is made of SiO2 with a thickness of 102.0 nm, and the first high-refractive-index dielectric layer 102 is made of SiN. x The thickness is 74.6 nm, and the period number k1 is 6. The structure of the second dielectric film group B is H2 (L2H2). k2 (H2L2) k2 H2 and L2 are low-refractive-index dielectric material layers, H2 is a high-refractive-index dielectric material layer, and k2 is the period number. The second low-refractive-index dielectric layer 201 is made of SiO2 with a thickness of 85.0 nm, and the second high-refractive-index dielectric layer 202 is made of SiN. x The thickness is 62.2 nm, and the period number K2 is 5.

[0020] Figure 6 It is the reflectance spectrum of a visible light band tunable dual-channel filter. The transmittance of the 604 nm filter channel is close to 100%, and the full width at half maximum (FWHM) of the 604 nm filter channel is 9 nm. The transmittance of the 508 nm filter channel is 75%, and the FWHM of the 508 nm filter channel is 10 nm. The reflectance is greater than 90% in the wavelength ranges of 447 nm to 502 nm, 523 nm to 597 nm, and 619 nm to 695 nm. Example

[0021] A visible light band tunable dual-channel filter, with the structure as follows: Figure 1 As shown, substrate 000 is a quartz sheet. The structure of the first dielectric film group A is (L1H1). k1 (H1L1) k1 L1 is the first low-refractive-index dielectric layer 101, H1 is the first high-refractive-index dielectric layer 102, and k1 is the period number. The first low-refractive-index dielectric layer 101 is made of SiO2 with a thickness of 110.5 nm, and the first high-refractive-index dielectric layer 102 is made of TiO2 with a thickness of 68.9 nm. The period number k1 is 6. The structure of the second dielectric film group B is H2 (L2H2). k2 (H2L2) k2 H2 and L2 are the second low-refractive-index dielectric layers, H2 is the second high-refractive-index dielectric layer, and k2 is the period number. The second low-refractive-index dielectric layer 201 is made of SiO2 with a thickness of 89.9 nm, and the second high-refractive-index dielectric layer 202 is made of SiN. xThe thickness is 65.7nm, and the period K2 is 5.

[0022] Figure 7 It is the reflectance spectrum of a tunable dual-channel filter in the visible light band. The transmittance of the filter channel at 654 nm is close to 67%, and the full width at half maximum (FWHM) of the filter channel at 654 nm is 3 nm. The transmittance of the filter channel at 530 nm is 90%, and the FWHM of the filter channel at 530 nm is 5 nm. The reflectance is greater than 90% in the wavelength ranges of 470 nm to 527 nm, 549 nm to 649 nm, and 656 nm to 794 nm.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A visible light band tunable dual-channel filter, characterized in that: It includes a visible light transparent substrate and a dielectric filter. The dual channels of the dielectric filter are located at 400 nm to 700 nm. The transmittance of the dual channels of the dielectric filter is >60%. The dielectric filter consists of two sets of dielectric films, denoted as the first dielectric film set A and the second dielectric film set B. The first dielectric film set A controls the position of the long wavelength channel, and the second dielectric film set B controls the position of the short wavelength channel. The first dielectric film group A has the following characteristics: the transmittance of the peak value λ1 of the filter channel of the first dielectric film group A is greater than 60%; the full width at half maximum (FWHM) of the filter channel of the first dielectric film group A is less than 30 nm; and the wavelength range on both sides of the peak value λ1 of the filter channel of the first dielectric film group A with reflectance greater than 90% is λ. 11 ~λ 12 and λ 13 ~λ 14 , where: λ 11 <λ 12 <λ1<λ 13 <λ 14 , λ 12 -λ 11 >30nm, λ 14 -λ 13 >30 nm; The second dielectric film group B has the following characteristics: the transmittance of the peak value λ2 of the filter channel of the second dielectric film group B is greater than 60%; the full width at half maximum (FWHM) of the filter channel of the second dielectric film group B is less than 30 nm; and the wavelength range in which the reflectance on both sides of the peak value λ2 of the filter channel of the second dielectric film group B is greater than 90% is λ. 21 ~λ 22 and λ 23 ~λ 24 , where: λ 21 <λ 22 <λ2<λ 23 <λ 24 , λ 22 -λ 21 >30 nm, λ 24 -λ 23 >30 nm; λ of the first dielectric membrane group A 11 λ greater than that of the second dielectric film group B 23 Meanwhile, the λ of the second dielectric membrane group B 24 λ is less than that of the first dielectric film group A 12 ; The structure of the first dielectric membrane group A is (L1H1). k1 (H1L1) k1 L1 is the first low-refractive-index dielectric layer, H1 is the first high-refractive-index dielectric layer, and k1 is the period number; the structure of the second dielectric film group B is H2 (L2H2). k2 (H2L2) k2 H2 and L2 are the second low-refractive-index dielectric layers, H2 is the second high-refractive-index dielectric layer, and k2 is the period number.

2. The visible light band tunable dual-channel filter according to claim 1, characterized in that: The position of the long-wavelength channel is controlled by changing the thickness of the dielectric material layer in the first dielectric film group A, and the position of the short-wavelength channel is controlled by changing the thickness of the dielectric material layer in the second dielectric film group B.

3. The visible light band tunable dual-channel filter according to claim 1, characterized in that: The low-refractive-index dielectric layer is SiO2; the high-refractive-index dielectric layer is SiNx or TiO2.

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