CN101363928B - Optical reflectance coating - Google Patents

Abstract

The invention discloses an optical reflecting film which is formed by superimposing a plurality of repetitive units. Each repetitive unit is formed by combing a first multilayer film unit with a second multilayer film units; the first multilayer film units and the second multilayer film units are all formed by mutually superimposing first polymeric layers A and second polymeric layers B; and the refractive index difference of the first polymeric layers A and the second polymeric layers B is at least 0.03. The superimposing way of the first multilayer film units is 1A:xB:1A; the superimposing way of the second multilayer film units is 1B:yA:1B; and x and y represent the multiples of the optical thickness of the intermediate polymeric layer relative to the adjacent polymeric layers, wherein,x and y are mutually unequal, and are proportional; and to the lights within the wavelength range of visible lights, the ratio of the equivalent refractive index of the first multilayer film units and the second multilayer film units is about 1.00.

Description

A kind of optical reflectance coating

Technical field

What the present invention relates to is a kind of optical reflectance coating, but particularly be a kind of reflected infrared wavelength section, but can allow the optical reflectance coating of visible wavelength transmission.

Background technology

In general, optical reflectance coating is to be used in to allow the light of certain wavelength section pass through, and allows the optical module of light reflection of other wavelength section.At United States Patent (USP) 3,711, mention in No. 176 by two kinds of polymeric layers optical reflectance coating of forming of superposition each other, by the difference of two kinds of polymeric layers refractive index to each other, can make incident light produce constructive interference (constructive interference).So, optical reflectance coating can allow the light of specific wavelength pass through, and allows the light of other wavelength reflect.

Above-mentioned optical reflectance coating, the spectrum major decision of its reflection and transmission is at the optical thickness of polymeric layer, and so-called optical thickness is meant the thickness of polymeric layer and the product of refractive index.With regard on the mathematics, the light of the first rank wavelength that optical reflectance coating reflected (first order wave length), its wavelength can be expressed as following equation:

${\mathrm{\λ}}_I=2\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\left(n_i{d}_i\right)...\left(1\right)$

In equation (1), λ _IBe the first rank wavelength (first order wave length), n is the refractive index of polymeric layer, and d is the thickness of polymeric layer, and k then is the number of polymeric layer.In addition, above-mentioned optical reflectance coating also can be with the light reflection of higher-order wavelength (higher order wave length) except the light reflection of meeting with the first rank wavelength.With regard on the mathematics, the light of the higher-order wavelength that optical reflectance coating reflected, its wavelength can be expressed as following equation:

${\mathrm{\λ}}_m=(2/m)\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\left(n_i{d}_i\right)...\left(2\right)$

In equation (2), λ _mBe the higher-order wavelength, m is the integer greater than 1.From equation (2), λ as can be known _mLess than λ _ISo, if λ _IDrop on the wavelength coverage of near infrared light (near infrared dlight), also promptly: wavelength between 780nm and 2500nm, certain some λ then _mJust can drop on the scope of visible light, also promptly: wavelength is between 380nm and 780nm.For example, if λ ₁Be 1800nm, then λ ₂With λ ₃Just be respectively 900nm and 600nm.Also because so, above-mentioned optical reflectance coating just can produce iris (iridescence) phenomenon.

Yet,, do not wish that the visible light that will belong to the higher-order wavelength reflects in some application scenario.For example, be attached to building optical reflectance coating on glass, this optical reflectance coating must make extraneous infrared light reflection, with the burden of the air-conditioning system that alleviates the building; But this optical reflectance coating also must allow visible transmission, so that there is illumination fully inside, building.Therefore, United States Patent (USP) 3,711, No. 176 described optical reflectance coating does not just meet this demand.

In view of this, United States Patent (USP) 5,360, No. 659 a kind of optical reflectance coating is just disclosed, this optical reflectance coating is formed by two kinds of different polymeric layer institute superpositions of refractive index, and its superposition mode is 1L:7H:1L:1H:7L:1H, and wherein H represents the higher polymeric layer of reflectivity, and L represents the lower polymeric layer of reflectivity, and the numeral before H and the L (also being 7 or 1) is the optical thickness ratio of representation polymer interlayer then.Via simulation, United States Patent (USP) 5,360, No. 659 described optical reflectance coatings can allow the near infrared light reflection effectively, and allow visible transmission.

Yet in some cases, this area has knows that usually the knowledgeable does not wish the superposition mode of polymeric layer to be confined to United States Patent (USP) 5,360, the mode described in No. 659.Therefore, how allowing the range of choice of superposition mode of polymeric layer enlarge, can make optical reflectance coating reflect near infrared light and visible light transmissive effectively again simultaneously, is to be worth this area to have to know that usually the knowledgeable considers ground.

Summary of the invention

The purpose of this invention is to provide a kind of optical reflectance coating, described optical reflectance coating can allow the range of choice of superposition mode of polymeric layer enlarge, simultaneously reflect near infrared light and visible light transmissive effectively again.

According to above-mentioned purpose and other purpose, the invention provides a kind of optical reflectance coating, it is formed by a plurality of repetitive institute superposition.Above-mentioned repetitive is formed by one first multilayer film unit and one second multilayer film unit combination, the first multilayer film unit and the second multilayer film unit are all formed by the first polymeric layer A and the mutual superposition of the second polymer layer B, and the refractive index difference of the first polymeric layer A and the second polymer layer B is between 0.03 and 0.2.The superposition mode of the first multilayer film unit is 1A:xB, and wherein, x represents the multiple of the optical thickness of the second polymer layer B with respect to the first adjacent polymeric layer A.The superposition mode of the second multilayer film unit is 1B:yA, and wherein, y represents the multiple of the optical thickness of the first polymeric layer A with respect to adjacent the second polymer layer B.Wherein, the unequal each other but proportional relation of x, y.For the light that drops in the visible wavelength range, the ratio of the equivalent refractive index of the first multilayer film unit and the second multilayer film unit is about 1.00.

In above-mentioned optical reflectance coating, the refringence of the first polymeric layer A and the second polymer layer B is at least 0.05.

In above-mentioned optical reflectance coating, the ranges of indices of refraction of the first polymeric layer A and the second polymer layer B is between 1.4 and 2.0.

In above-mentioned optical reflectance coating, the ranges of indices of refraction of the first polymeric layer A and the second polymer layer B is between 1.5 and 1.85.

In above-mentioned optical reflectance coating, the refringence of the first polymeric layer A and the second polymer layer B can be between 0.05 and 0.2.

In above-mentioned optical reflectance coating, the material of the first polymeric layer A is for being selected from the group that polycarbonate (polycarbonate), polystyrene (polystyrene), polyethylene terephthalate (polyethyleneterephthalate) and polymethylmethacrylate (polymethylmethacrylate) are constituted.And the material of the second polymer layer B is to be selected from the group that polycarbonate, polystyrene, polyethylene terephthalate and polymethylmethacrylate constitute.

In above-mentioned optical reflectance coating, x, y are unequal each other.In its preferred embodiment, the proportionate relationship of x and y can be 7.2: 6.8 or 6.8: 7.2.

In above-mentioned optical reflectance coating, x, y difference each other can be greater than 2.In preferred embodiment, the proportionate relationship of x and y is 8.4: 6 or 6: 8.4.

In above-mentioned optical reflectance coating, x, y difference each other can be greater than 4.In preferred embodiment, the proportionate relationship of x and y is 10: 5.4 or 5.4: 10.

In above-mentioned optical reflectance coating, x, y difference each other can be greater than 5.In preferred embodiment, the proportionate relationship of x and y is 10.8: 5.2 or 5.2: 10.8.

In above-mentioned optical reflectance coating, the thickness of each repetitive is different along with the thickness direction of optical reflectance coating.In preferred embodiment, the thickness of each repetitive is linearity or index ground increasing or decreasing along with the thickness direction of optical reflectance coating, yet is not limited thereto.

By optical reflectance coating of the present invention, can allow the range of choice of superposition mode of polymeric layer enlarge, can make optical reflectance coating reflect near infrared light and visible light transmissive effectively simultaneously again.

Description of drawings

Fig. 1 is the sectional view of the optical reflectance coating of this case;

Fig. 2 A and Fig. 2 B work as n _A=1.5, n _B=1.6 and λ when being 500nm, x, y and E ₁/ E ₂Between relation table;

Fig. 3 A and Fig. 3 B are for working as n _A=1.5, n _B=1.7 o'clock, x, y and E ₁/ E ₂Between relation table;

Fig. 4 A and Fig. 4 B are for working as n _A=1.5, n _B=1.9 o'clock, x, y and E ₁/ E ₂Between relation table;

Fig. 5 is the optical reflectance coating and the comparison diagram of existing optical reflectance coating on filtering functions of this case.

Description of reference numerals: 100-optical reflectance coating; The 102-repetitive; The 110-first multilayer film unit; 120: the second multilayer film unit; A-first polymeric layer; The B-the second polymer layer.

Embodiment

Below in conjunction with accompanying drawing, be described in more detail with other technical characterictic and advantage the present invention is above-mentioned.

See also Fig. 1, Fig. 1 is the sectional view of the optical reflectance coating of this case.This optical reflectance coating 100 is to be formed by 102 superpositions of a plurality of repetitives, and the thickness of each repetitive 102 for example is to change along with the thickness direction of optical reflectance coating 100, for example be increasing or decreasing along with the increase of the thickness of optical reflectance coating and linearly, or along with the increase of the thickness of optical reflectance coating and index ground increasing or decreasing.In Fig. 1, the thickness of repetitive 102 is to increase progressively along with the increase of the thickness of optical reflectance coating 100.Wherein, the thickness of repetitive 102 that is positioned at the top is twices of the repetitive 102 of below.

Repetitive 102 is to be combined by one first multilayer film unit 110 and one second multilayer film unit 120.As shown in Figure 1, the first multilayer film unit 110 and the second multilayer film unit 120 are all formed by the first polymeric layer A and the mutual superposition of the second polymer layer B, wherein the first multilayer film unit 110 is plant one deck the second polymer layer B in two layer of first polymeric layer A, and the second multilayer film unit 120 then is plant one deck first polymeric layer A in two layers of the second polymer layer B.In the first multilayer film unit 110, its superposition mode is 1A:xB:1A, and wherein x represents the multiple of the optical thickness of the second polymer layer B with respect to the first adjacent polymeric layer A; For example, if the superposition mode of the first multilayer film unit 110 is 1A:7B:1A, the optical thickness of then representing the second polymer layer B is 7 times of the adjacent first polymeric layer A.In addition, in the second multilayer film unit 120, its superposition mode is 1B:yA:1B, and wherein y represents the multiple of the optical thickness of the first polymeric layer A with respect to adjacent the second polymer layer B.And x, y are proportional relation each other, and for example as x=7 and during y=9, the second polymer layer B that then represents the first multilayer film unit 110 is 7: 9 with the ratio of the first polymeric layer A on optical thickness of the second multilayer film unit 120.

In addition, for a specific wavelength, if the equivalent refractive index E of the first multilayer film unit 110 ₁Equivalent refractive index E with the second multilayer film unit 120 ₂More close, then the light of this specific wavelength more easily penetrates this repetitive 102.In fact, for the light that drops on visible wavelength range, work as E ₁With E ₂Ratio more near 1.00 o'clock, repetitive 102 is crossed in the break-through effectively of can healing.Wherein, the equivalent refractive index E of the first multilayer film unit 110 ₁Can try to achieve by following equation (3):

$m_1=\frac{1}{n_A}\left[\begin{array}{c}\sin 2{\mathrm{\δ}}_A{\cos \mathrm{\δ}}_B+\frac{1}{2}(\frac{n_B}{n_A}+\frac{n_A}{n_B}){\cos 2\mathrm{\δ}}_A{\sin \mathrm{\δ}}_B\\ +\frac{1}{2}(\frac{n_A}{n_B}-\frac{n_B}{n_A}){\sin \mathrm{\δ}}_B\end{array}\right]$

$o_1=n_A\left[\begin{array}{c}{\sin 2\mathrm{\δ}}_A{\cos \mathrm{\δ}}_B+\frac{1}{2}(\frac{n_B}{n_A}+\frac{n_A}{n_B}){\cos 2\mathrm{\δ}}_A{\sin \mathrm{\δ}}_B\\ -\frac{1}{2}(\frac{n_A}{n_B}-\frac{n_B}{n_A}){\sin \mathrm{\δ}}_B\end{array}\right]$

${\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="H2007101401729E00061.png"\; state="\{\{state\}\}">E</figure-callout>}}_1=\sqrt{\frac{o_1}{{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="H2007101401729E00061.png"\; state="\{\{state\}\}">m</figure-callout>}}_1}}...\left(3\right)$

In above-mentioned equation (3),

Wherein, d _AWith d _BRepresent the thickness of the first polymeric layer A and the second polymer layer B respectively.For the light of wavelength X, n _AWith n _BRepresent the refractive index of the first polymeric layer A and the second polymer layer B respectively.

In addition, the equivalent refractive index E of the second multilayer film unit 120 ₂Then can try to achieve by following equation (4):

$m_2=\frac{1}{n_B}\left[\begin{array}{c}\sin 2{\mathrm{\&delta;}}_B{\cos \mathrm{\&delta;}}_A+\frac{1}{2}(\frac{n_A}{n_B}+\frac{n_B}{n_A}){\cos 2\mathrm{\&delta;}}_B{\sin \mathrm{\&delta;}}_A\\ +\frac{1}{2}(\frac{n_B}{n_A}-\frac{n_A}{n_B}){\sin \mathrm{\&delta;}}_A\end{array}\right]$

$o_2=n_B\left[\begin{array}{c}{\sin 2\mathrm{\&delta;}}_B{\cos \mathrm{\&delta;}}_A+\frac{1}{2}(\frac{n_A}{n_B}+\frac{n_B}{n_A}){\cos 2\mathrm{\&delta;}}_B{\sin \mathrm{\&delta;}}_A\\ -\frac{1}{2}(\frac{n_B}{n_A}-\frac{n_A}{n_B}){\sin \mathrm{\&delta;}}_A\end{array}\right]$

$E_2=\sqrt{\frac{o_2}{m_2}}...\left(4\right)$

Under the situation of the wavelength X of knowing incident light, by the proportionate relationship between the optical thickness that changes the first polymeric layer A and the second polymer layer B, and utilize above-mentioned equation (3) and equation (4), can learn when x value and the variation of y value E ₁/ E ₂How value can change.Then, please refer to Fig. 2 A and Fig. 2 B, Fig. 2 A and Fig. 2 B show and work as n _A=1.5, n _B=1.6 and λ when being 500nm, x, y and E ₁/ E ₂Between relation table.

In Fig. 2 A and Fig. 2 B, the top one is classified the x value as, left one behavior y value, and all the other then are E ₁/ E ₂Value, wherein E ₁/ E ₂The degree of accuracy of value is got behind the radix point the 2nd.

By Fig. 2 A and Fig. 2 B as can be known, even under x value and the unequal situation of y value, this area has knows that usually the knowledgeable also can come by the table that Fig. 2 A and Fig. 2 B are illustrated x value and y value are selected, so that E ₁/ E ₂Remain on 1.00.By above-mentioned method, this area has the selectable range of knowing just extendible x value of the knowledgeable and y value usually, and does not really want to be confined to United States Patent (USP) 5,360, No. 659 described superposition modes.

Then, please refer to Fig. 3 A and Fig. 3 B, Fig. 3 A and Fig. 3 B show and work as n _A=1.5, n _B=1.7 o'clock, x, y and E ₁/ E ₂Between relation table.Come, please refer to Fig. 4 A and Fig. 4 B, Fig. 4 A and Fig. 4 B show and work as n _A=1.5, n _B=1.9 o'clock, x, y and E ₁/ E ₂Between relation table.By comparison diagram 2A and Fig. 2 B, Fig. 3 A and Fig. 3 B, Fig. 4 A and Fig. 4 B, work as n as can be known _AWith n _BGap more hour, the selectable range of x value and y value is bigger.So the refractive index difference of the first polymeric layer A and described the second polymer layer B is preferably between 0.05 and 0.2.And the ranges of indices of refraction of the first polymeric layer A and the second polymer layer B is preferably between 1.5 and 1.85 between 1.4 and 2.0.In addition, in the present embodiment, the material of the first polymeric layer A for example is polycarbonate, polystyrene, polyethylene terephthalate and polymethylmethacrylate or its potpourri, and the material of the second polymer layer B for example is polycarbonate, polystyrene, polyethylene terephthalate, polymethylmethacrylate or its potpourri.In addition, the applicant also can select: glycol-modified-polyethylene terephthalate (Polyethylene Terephthalate Glycol), glycol-modified PCT polyester (Polycyclohexylenedimethylene Terephthalate Glycol) or Polyethylene Naphthalate polymkeric substance such as (Polyethylene Naphthalate).

In addition, when the applicant found that difference as x, y is between 2 and 4, the proportionate relationship of x and y is preferable to be about 8.4: 6 or 6: 8.4; When the difference of x, y was between 4 and 5, the proportionate relationship of x and y is preferable to be about 10: 5.4 or 5.4: 10; And when the difference of x, y be 5 when above, the proportionate relationship of x and y is preferable to be about 10.8: 5.2 or 5.2: 10.8.Also promptly, when above-mentioned situation, E ₁With E ₂Ratio also convergence equating, so visible luminous energy also has the break-through of the ground of effect to cross repetitive 102.

Then, please refer to Fig. 5, Fig. 5 is the optical reflectance coating and the comparison diagram of existing optical reflectance coating on filtering functions of this case.In Fig. 5, " solid line " representative be that superposition mode with 1A:7B:1A:1B:7A:1B (also is, United States Patent (USP) 5,360, superposition mode described in No. 659) optical reflectance coating that is constituted, and " dotted line " representative is the optical reflectance coating that the superposition mode with 1A:6.8B:1A:1B:7.2A:1B is constituted.Fig. 5 is a numerical simulation result, and wherein the two optical reflectance coating all has 1800 one polymer layer, and the refractive index (n of the first polymeric layer A _A) be 1.5, and the refractive index (n of the second polymer layer B _B) be 1.7.

Can learn clearly that by Fig. 5 the optical reflectance coating of this case all has similar effect to existing optical reflectance coating on filtering.

In sum,, can allow the range of choice of superposition mode of polymeric layer enlarge, can make optical reflectance coating reflect near infrared light and visible light transmissive effectively simultaneously again by optical reflectance coating of the present invention.

The present invention illustrates as above that with embodiment so it is not in order to limit the patent right scope that the present invention advocated.Its scope of patent protection when on accompanying claim and etc. same domain decide.All this areas have knows the knowledgeable usually, and in not breaking away from this patent spirit or scope, the also moving or retouching of being done all belongs to the equivalence of being finished under the disclosed spirit and changes or design, and should be included in the following claim.

Claims (10)

1. optical reflectance coating, it is characterized in that: it is formed by a plurality of repetitive superpositions, described repetitive is formed by one first multilayer film unit and one second multilayer film unit combination, described first multilayer film unit and the described second multilayer film unit are all formed by the first polymeric layer A and the mutual superposition of the second polymer layer B, and the refractive index difference of described first polymeric layer A and described the second polymer layer B is between 0.03 and 0.2; The superposition mode of the described first multilayer film unit is 1A:xB, and wherein, x represents the multiple of the optical thickness of described the second polymer layer B with respect to the adjacent described first polymeric layer A; The superposition mode of the described second multilayer film unit is 1B:yA, and wherein, y represents the multiple of the optical thickness of the first polymeric layer A with respect to adjacent described the second polymer layer B; Wherein, the unequal each other but proportional relation of x, y, for the light in visible wavelength range, the ratio of the equivalent refractive index of described first multilayer film unit and the described second multilayer film unit is 1.00.

2. optical reflectance coating according to claim 1 is characterized in that: the ranges of indices of refraction of described first polymeric layer A and described the second polymer layer B is between 1.4 and 2.0.

3. optical reflectance coating according to claim 1 is characterized in that: described x, y difference each other is greater than 2.

4. optical reflectance coating according to claim 3 is characterized in that: the proportionate relationship of described x and y is 8.4: 6 or 6: 8.4.

5. optical reflectance coating according to claim 1 is characterized in that: described x, y difference each other is greater than 4.

6. optical reflectance coating according to claim 5 is characterized in that: the proportionate relationship of described x and y is 10: 5.4 or 5.4: 10.

7. optical reflectance coating according to claim 1 is characterized in that: described x, y difference each other is greater than 5.

8. optical reflectance coating according to claim 7 is characterized in that: the proportionate relationship of described x and y is 10.8: 5.2 or 5.2: 10.8.

9. optical reflectance coating according to claim 1 is characterized in that: the thickness of described each repetitive is increasing or decreasing linearly along with the increase of the thickness of described optical reflectance coating.

10. optical reflectance coating according to claim 1 is characterized in that: the proportionate relationship of described x and y is 7.2: 6.8 or 6.8: 7.2.

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