CN211236324U - Infrared band-pass filtering structure and infrared band-pass filter using same - Google Patents

Abstract

The utility model provides an infrared band-pass filtering structure is formed by the mutual stack of plural hydrogenated silicon aluminum layer and plural lower refractive index layer, and this plural lower refractive index layer is an oxide, and this infrared band-pass filtering structure has a passband that 800nm to 1600 nm's wavelength range at least part overlaps, and this passband has a central wavelength, and this central wavelength changes from 0 to 30 when the incident angle, and the offset amplitude is less than 11nm in the magnitude; the infrared band-pass filter is characterized in that the infrared band-pass filtering structure is formed on a first side surface of a substrate, and an anti-reflection layer is formed on a second side surface, opposite to the first side surface, of the substrate; therefore, the sputtering efficiency can be improved to greatly reduce the manufacturing cost, and the warping amount of the film layer can be reduced to solve the problem that the corner is easy to break in the subsequent cutting.

Description

Infrared band-pass filtering structure and infrared band-pass filter using same

Technical Field

The utility model relates to a technical field in the aspect of the structure of infrared band-pass filtering structure and wave filter indicates especially one kind and can promote sputter efficiency in order to reduce the cost of manufacture by a wide margin to and can reduce the infrared band-pass filtering structure of the warpage volume of rete in order to solve the system after and cut the infrared band-pass filter person who easily collapses the angle problem and use this structure.

Background

The general optical filters can be classified into a band pass filter, a short wavelength cut filter, and a long wavelength cut filter according to spectral characteristics. The bandpass filter is a filter which selects light of a specific waveband to pass, cuts off light outside a passband, is divided into a narrow band and a wide band according to bandwidth, is generally distinguished according to the bandwidth to the value of a central wavelength, and is a narrow band when less than 5 percent and a wide band when more than 5 percent. In order to reduce the interference of ambient visible light, narrow-band interference filters are commonly used. The traditional RGB visible light camera needs to adopt an infrared cut-off filter to filter out unnecessary low-frequency near infrared light so as to prevent the infrared light from influencing visible light, generate false color or ripple and simultaneously improve effective resolution and color reducibility. However, in order to avoid the interference of ambient light, the infrared camera needs to use a narrow-band filter (i.e., an infrared band-pass filter) to allow only near-infrared light of a specific wavelength band to pass through.

One commonly known infrared bandpass filter, as shown in U.S. Pat. Nos. I576617 and I648561 of the optical filter and sensing system, is mainly formed by alternately stacking a plurality of hydrogenated silicon layers and a plurality of lower refractive index layers, and has a passband (passband) at least partially overlapping in a wavelength range of 800nm to 1600nm, the passband having a center wavelength, and the center wavelength being shifted (shifted) in magnitude (magnitude) by about 12.2 to 20nm when the incident angle is changed from 0 DEG to 30 deg. Wherein each of the plurality of hydrogenated silicon layers has a refractive index greater than (near) 3.5 over the wavelength range of 800nm to 1100nm, the plurality of lower refractive index layers is an oxide, has a refractive index less than 2 over the wavelength range of 800nm to 1100nm, and may comprise silicon dioxide (SiO)₂) Alumina (Al)₂O₃) Titanium dioxide (TiO)₂) Niobium pentoxide (Nb)₂O₅) Tantalum pentoxide (Ta)₂O₅) And mixtures thereof.

However, it is generally known that infrared band-pass filters have the following disadvantages in practical implementation:

1. it is generally known that the center wavelength of the passband of the ir band filter formed by the alternating stack of hydrogenated silicon layers and lower refractive index layers has a large offset (about 12.2-20 nm) when the incident angle is changed from 0 ° to 30 °, which easily causes the problem of being unable to identify or failing to identify when the ir band filter is applied to a three-dimensional imaging system and receiving light at a large angle.

2. The film layer of the commonly known infrared band-pass filter is formed by sputtering a pure silicon target, the pure silicon target can only use 5-6KW of power to perform sputtering process, and the excessive power will cause target cracking of the pure silicon target and make the pure silicon target unusable, so that it takes much time to sputter the film layer, which makes the sputtering efficiency very poor, and further increases the manufacturing cost (such as electricity cost, man-hour …, etc.).

3. The conventional infrared band pass filter has a thick film layer, so that the film layer is plated on a glass substrate to generate a large warpage, which causes a problem of a severe corner collapse during a subsequent cutting process.

In view of the above, the applicant of the present invention has made extensive and intensive studies and improvements to solve the above-mentioned problems, and has developed and designed the present invention.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a main aim at solve spatter inefficiency that generally known infrared band pass filter exists and lead to the cost of manufacture high to and the warpage volume of rete easily produces a great deal of problems such as collapsing angle when leading to the back system cutting.

Infrared band-pass filtering structure, form by the mutual storehouse of plural hydrogenated silicon aluminium layer and the lower refracting index layer of plural number, this lower refracting index layer of plural number is an oxide, this infrared band-pass filtering structure has a passband of 800nm to 1600 nm's at least partial overlap in the wavelength range, this passband has a central wavelength, and this central wavelength changes from 0 to 30 when the incident angle, offset amplitude is less than 11nm in the magnitude.

The infrared band-pass filter mainly forms the infrared band-pass filtering structure on a first side of a substrate, and an anti-reflection layer is formed on a second side of the first side opposite to the substrate.

The utility model provides an infrared band-pass filter of infrared band-pass filtering structure and applied this structure, the central wavelength of its passband that utilizes the mutual storehouse of this complex number hydrogenated silicon aluminium layer and this complex number lower refractive index layer to form infrared band filtering structure has less offset that is less than 11nm when the angle of incidence changes to 30 from 0, is difficult for taking place unable discernment or the problem of discernment failure when consequently being applied to three-dimensional imaging system. In particular, when the hydrogenated Si-Al is prepared by using the Si-Al target doped with the aluminum component, the power output (about 10-20KW) can be more than 2 times that of the hydrogenated Si prepared by using the commonly known pure Si target, so that the coating time can be at least halved, the relative simultaneous output can be more than one time, the cost of resources including the production time, the labor power, the electric power and the like of the whole plant can be also halved, and the competitive advantage is greatly improved. Moreover, the film layer of the infrared band-pass filtering structure can be made into smaller thickness through the characteristic of good ductility of aluminum components, so that the internal stress is relatively smaller when the film is plated on a glass substrate and is small, the subsequent cutting process can reduce the occurrence of corner collapse due to the small internal stress, the yield of cutting manufacture is improved, and the aim of reducing the cost is relatively further achieved.

Drawings

Fig. 1 is a schematic cross-sectional view of an infrared band-pass filter according to the present invention;

FIG. 2 is a schematic structural view of a vacuum sputtering coating system for performing a coating process according to the present invention;

fig. 3 is a schematic diagram of a film structure of a first embodiment of the infrared band-pass filter structure of the present invention;

fig. 4 is a spectrum diagram of a first embodiment of the infrared band-pass filtering structure of the present invention;

fig. 5 is a schematic diagram of a first experimental film structure according to a second embodiment of the infrared band-pass filter structure of the present invention;

fig. 6 is a spectrum diagram of experiment one of the second embodiment of the infrared band-pass filtering structure of the present invention;

fig. 7 is a schematic diagram of a second experimental film layer structure according to a second embodiment of the infrared band-pass filter structure of the present invention;

fig. 8 is a spectrum diagram of a second experiment according to a second embodiment of the infrared band-pass filter structure of the present invention;

fig. 9 is a schematic diagram of a film structure of a third embodiment of the infrared band-pass filter structure of the present invention;

fig. 10 is a spectral diagram of a third embodiment of an infrared bandpass filtering structure of the present invention;

fig. 11 is a film structure diagram of the visible light reflectivity experiment of the infrared band-pass filter structure of the present invention;

fig. 12 is a spectrum diagram of a visible light reflectivity experiment of the infrared band-pass filter structure of the present invention;

fig. 13 is a color coordinate range diagram of the visible light reflectivity experiment of the infrared band-pass filter structure of the present invention.

Detailed Description

Referring to fig. 1, it is shown that the infrared band pass filter of the present invention includes a substrate 10, an infrared band pass filter structure 20 and an anti-reflection (AR) layer 30, wherein:

the substrate 10 is made of glass and has a first side surface and a second side surface opposite to the first side surface.

The infrared band-pass filter structure 20 is formed on the first side of the substrate 10 by alternately stacking a plurality of silicon aluminum hydride (SiAl: H) layers 21 and a plurality of lower refractive index layers 22, such that the infrared band-pass filter structure 20 has a passband (passband) at least partially overlapping in a wavelength range of 800nm to 1600nm, the passband having a center wavelength, and the center wavelength shifts (shifts) in magnitude (amplitude) by less than 11nm (about 10.3 to 10.5nm) when an incident angle is changed from 0 ° to 30 °. Moreover, the thickness of the infrared band-pass filter structure 20 is 3000-5500 nm, the infrared band-pass filter structure has a high OD value in the wavelength range of 350-1600 nm and a high transmittance in the wavelength range of 800-1600 nm, the color coordinates are located at Rx Coordinate 0.2-0.5 and Ry Coordinate 0.2-0.5 in the visible light range, and the reflectivity is lower than 20%. Wherein the complex hydrogenated silicon aluminumThe layer 21 has a refractive index of 3.1 to 3.6 in the wavelength range of 800nm to 1600nm, an extinction coefficient of 1.E-4 to 1.E-6, and an extinction coefficient of greater than 0.005 in the wavelength range of 350nm to 700 nm. Wherein the lower refractive index layer 22 is an oxide comprising silicon aluminum oxide (SiAl: O)₂) Silicon dioxide (SiO)₂) Alumina (Al)₂O₃) Titanium dioxide (TiO)₂) Niobium pentoxide (Nb)₂O₅) Tantalum pentoxide (Ta)₂O₅) And mixtures thereof. Also, the refractive index of the plurality of lower refractive index layers 22 in the wavelength range of 800nm to 1600nm is less than 1.8, the extinction coefficient is less than 0.0005, and the extinction coefficient in the wavelength range of 350nm to 700nm is greater than 0.005.

The anti-reflection layer 30 is formed on the second side of the substrate 10 by stacking a plurality of high refractive index materials such as silicon aluminum hydride (SiAl: H) and a plurality of low refractive index materials such as silicon aluminum oxide (SiAl: O2), silicon aluminum nitride (SiAl: N), silicon nitride (SiN), silicon dioxide (SiO2), and aluminum oxide (Al)₂O₃) Titanium dioxide (TiO)₂) Niobium pentoxide (Nb)₂O₅) Tantalum pentoxide (Ta)₂O₅) And mixtures thereof, and a thickness of 3000nm to 6000 nm.

Please refer to fig. 2, which indicates that the sputtering process of the hydrogenated silicon aluminum film layer 21 of the present invention is performed in a vacuum sputtering reactive coating system 40, which mainly uses silicon cylindrical targets with various structures doped with aluminum components of 200 ppm-1500 ppm as the target material 45 for sputtering, and the manufacturing process is (a) placing the clean substrate 10 on the roller 41 with the coating surface facing outward; (B) the roller 41 rotates at a constant speed in the coating chamber 42; (C) when the vacuum degree is 10 < -3 > to 10 < -4 > Pa, starting a sputtering source 43 and introducing argon, ionizing the argon to form plasma, bombarding a silicon-aluminum target material 45 under the action of an electric and magnetic field, and sputtering a silicon-aluminum material onto the substrate 10 to form a silicon-aluminum film; (D) as the drum 200 rotates, the substrate 100 is brought to the reaction source (RF/ICP) region 44; (E) the reaction source region 44 is filled with hydrogen, oxygen and argon to form plasma, which moves towards the substrate 10 at high speed under the action of the electric field, and finally reacts with the silicon-aluminum film on the substrate 10 to synthesize the hydrogen-containing hydrogenated silicon-aluminum film layer 21. When a high refractive index thin film is prepared, the highest refractive index of 800nm to 1600nm can be gradually changed from 3.1 to 4 by adjusting the proportion (flow rate) of hydrogen in the mixed gas filled in the reaction source region 44, and the extinction coefficient of the thin film can be less than 0.0005. When the gas filled in the reaction source region 44 is a mixed gas of oxygen and argon, a film having a refractive index of 350nm to 1600nm gradually varying from 1.46 to 1.7 and an extinction coefficient of less than 0.0005 can be produced.

Referring to fig. 3 and 4, a first embodiment (850bandpass filter) of the infrared bandpass filtering structure of the present invention is formed by stacking 27 layers of hydrogenated silicon aluminum layer and silicon aluminum layer, wherein the thickness of the stacked layers is about 3500 nm. Wherein the refractive index of the alumina layer is greater than 3 and close to 3.6 in the wavelength range of 800nm to 1600nm, the extinction coefficient is less than 0.0005, and the extinction coefficient is greater than 0.005 in the wavelength range of 350nm to 700 nm. The silica aluminum layer has a refractive index of less than 1.8 and an extinction coefficient of less than 0.0005 over a wavelength range of 800nm to 1600 nm. The infrared band-pass filter structure formed by stacking has a passband at least partially overlapped in the wavelength range of 800nm to 1600nm, and the shift amplitude of the central wavelength of the passband is less than 11nm when the incident angle is changed from 0 DEG to 30 deg. When the method is applied to a three-dimensional imaging system, the three-dimensional image analysis capability can be improved.

Please refer to fig. 5 and 6, which are a first experiment (940 bandpass filter) according to a second embodiment of the infrared bandpass filtering structure of the present invention, wherein 31 layers of hydrogenated silicon aluminum layer and silicon aluminum layer are stacked on each other, and the stacking thickness is about 4000 nm. Wherein the refractive index of the alumina layer is greater than 3 and close to 3.6 in the wavelength range of 800nm to 1600nm, the extinction coefficient is less than 0.0005, and the extinction coefficient is greater than 0.005 in the wavelength range of 350nm to 700 nm. The silica aluminum layer has a refractive index of less than 1.8 and an extinction coefficient of less than 0.0005 over a wavelength range of 800nm to 1600 nm. The infrared band-pass filter structure formed by stacking has a passband at least partially overlapped in the wavelength range of 800nm to 1600nm, and the shift amplitude of the central wavelength of the passband is less than 11nm when the incident angle is changed from 0 DEG to 30 deg. When the method is applied to a three-dimensional imaging system, the three-dimensional image analysis capability can be improved.

Please refer to fig. 7 and 8, which show a second experiment (940 bandpass filter) according to a second embodiment of the infrared bandpass filtering structure of the present invention, which is formed by mutually stacking 35 layers of hydrogenated silicon aluminum layer and silicon dioxide aluminum layer, and the thickness of the mutual stack is about 4000-550 nm. Wherein the refractive index of the alumina layer is greater than 3 and close to 3.6 in the wavelength range of 800nm to 1600nm, the extinction coefficient is less than 0.0005, and the extinction coefficient is greater than 0.005 in the wavelength range of 350nm to 700 nm. The silica aluminum layer has a refractive index of less than 1.8 and an extinction coefficient of less than 0.0005 over a wavelength range of 800nm to 1600 nm. The infrared band-pass filtering structure formed by stacking has a passband at least partially overlapped in the wavelength range of 800nm to 1600nm, the shift amplitude of the central wavelength of the passband is less than 11nm when the incident angle is changed from 0 DEG to 30 DEG, the slope of T90-T10% of the infrared band-pass filtering structure is better than that of the first example (experiment one slope is less than 8 experiment two slope is less than 7), and the OD value at the same position is also better than that of the first example.

Referring to fig. 9 and 10, a third embodiment (1064bandpass filter) of the infrared bandpass filtering structure of the present invention is formed by stacking 33 hydrogenated si-al layers and silica-al layers, wherein the thickness of the stack is below 5000 nm. Wherein the refractive index of the alumina layer is greater than 3 and close to 3.6 in the wavelength range of 800nm to 1600nm, the extinction coefficient is less than 0.0005, and the extinction coefficient is greater than 0.005 in the wavelength range of 350nm to 700 nm. The silica aluminum layer has a refractive index of less than 1.8 and an extinction coefficient of less than 0.0005 over a wavelength range of 800nm to 1600 nm. The infrared band-pass filter structure formed by stacking has a passband at least partially overlapped in the wavelength range of 800nm to 1600nm, the offset amplitude of the center wavelength of the passband is less than 2nm when the incident angle is changed from 0 DEG to 7 DEG, and the OD is greater than 3 when the incident angle of the passband in the wavelength ranges of 400 to 1000nm and 1120 to 1600 DEG is changed from 0 DEG to 7 deg.

Please refer to fig. 11-13, which are the visible light reflectivity experiments of the infrared band-pass filter structure of the present invention, the visible light reflectivity experiments are formed by mutually pushing and overlapping 37 hydrogenated silicon aluminum layers and silicon aluminum layers, the color coordinates are located at the x-axis Coordinate 0.2-0.5 and the y-axis Coordinate 0.2-0.5 in the visible light range, and the reflectivity is lower than 20%.

The utility model provides an infrared band-pass filter of infrared band-pass filtering structure and applied this structure has following advantage:

1. the utility model discloses the central wavelength of the passband of the infrared band filtering structure 20 that forms by the mutual stack of this plural number hydrogenated silicon aluminium layer 21 and this plural number lower refractive index layer 22 can be less than 11 nm's less offset (10.3 ~ 10.5nm) when the angle of incidence changes to 30 from 0, is difficult for taking place unable discernment or the problem of discernment failure when consequently being applied to three-dimensional imaging system.

2. The utility model discloses a mix aluminium composition's silicon-aluminum target can bear power output more than 2 times (about 10-20KW) than the well-known pure silicon target usually, consequently can make the coating time shorten half at least, relative time output alright with more than one time, cause including resource costs such as whole factory production time, manpower, electric power also can reduce half, improve the competitive advantage greatly.

3. The utility model discloses a rete can be by the good characteristic of aluminium composition ductility and can make less thickness, so plate less membrane thick then the internal stress is less relatively when locating on the glass substrate, and the internal stress can make subsequent cutting process reduce the condition emergence of collapsing the angle for a short time to improve the yield that the cutting was made, relative further reaches reduce cost's purpose.

In summary, the present invention has the advantages and practical value, and similar products are not published in the same kind of products, so the application requirements of the present invention are met, and the application is still provided.

[ notation ] to show

10 base plate

20 infrared band-pass filter structure 21 alumina silica layer

22 lower refractive index layer

30 anti-reflection layer

40 vacuum sputtering reaction coating system 41 roller

42 coating chamber 43 sputtering source

44 reaction source region 45 target

Claims (13)

1. An infrared band-pass filter structure, characterized in that the infrared band-pass filter structure is formed by alternately stacking a plurality of hydrogenated silicon aluminum (SiAl) layers, H layers, and a plurality of lower refractive index layers having a refractive index lower than the plurality of hydrogenated silicon aluminum layers, the plurality of lower refractive index layers being an oxide, the infrared band-pass filter structure having a passband pasband at least partially overlapping in a wavelength range of 800nm to 1600nm, the passband having a center wavelength, and the center wavelength shifting a shifts amplitude by less than 11nm in a magnitude when an incident angle is changed from 0 ° to 30 °.

2. The infrared band-pass filter structure of claim 1, wherein the infrared band-pass filter structure has a thickness of 3000 to 5500 nm.

3. The infrared bandpass filter structure of claim 1 wherein the infrared bandpass filter structure has a high OD value in the wavelength range of 350nm to 1600nm and a high transmittance in the wavelength range of 800nm to 1600 nm.

4. The infrared bandpass filter structure of claim 1 wherein the infrared bandpass filter structure has a color coordinate of 0.2 to 0.5 in x-axis coordinate and 0.2 to 0.5 in y-axis coordinate in visible light range and a reflectivity of less than 20%.

5. The infrared band-pass filter structure of claim 1, wherein the plurality of aluminum hydrosilicide layers have a refractive index of 3.1-3.6 in the wavelength range of 800nm to 1600nm, an extinction coefficient of 1. E-4-1. E-6, and an extinction coefficient of greater than 0.005 in the wavelength range of 350nm to 700 nm.

6. The infrared bandpass filter structure of claim 1 wherein the plurality of lower index layers have a refractive index of less than 1.8 and an extinction coefficient of less than 0.0005 over the wavelength range of 800nm to 1600 nm.

7. An infrared band pass filter, comprising:

the substrate is provided with a first side surface and a second side surface which is positioned on the opposite side of the first side surface;

an infrared bandpass filter structure formed on the first side of the substrate by alternating stacks of a plurality of hydrogenated silicon aluminum (SiAl) H layers and a plurality of lower refractive index layers, wherein the plurality of lower refractive index layers are oxides, the infrared bandpass filter structure has a passband which is at least partially overlapped in a wavelength range of 800nm to 1600nm, the passband has a center wavelength, and the center wavelength shifts amplitude on a magnitude of less than 11nm when an incident angle is changed from 0 DEG to 30 DEG; and

an anti-reflective AR layer formed on the second side of the substrate.

8. The infrared band-pass filter of claim 7, characterized in that the thickness of the infrared band-pass filter structure is 3000-5500 nm.

9. The infrared bandpass filter according to claim 7 wherein the infrared bandpass filtering structure has a high OD in the wavelength range of 350nm to 1600nm and a high transmittance in the wavelength range of 800nm to 1600 nm.

10. The infrared band-pass filter of claim 7, wherein the infrared band-pass filter structure has a color coordinate of 0.2 to 0.5 in x-axis coordinate and 0.2 to 0.5 in y-axis coordinate in visible light range and a reflectivity of less than 20%.

11. The infrared bandpass filter of claim 7 wherein the plurality of aluminum hydrosilicide layers have a refractive index of 3.1 to 3.6 over a wavelength range of 800nm to 1600nm, an extinction coefficient of 1.E-4 to 1.E-6, and an extinction coefficient greater than 0.005 over a wavelength range of 350nm to 700 nm.

12. The infrared bandpass filter of claim 7 wherein the plurality of lower index layers have a refractive index of less than 1.8 over a wavelength range of 800nm to 1600nm, an extinction coefficient of less than 0.0005 and an extinction coefficient of greater than 0.005 over a wavelength range of 350nm to 700 nm.

13. The infrared bandpass filter of claim 7 wherein the antireflective layer has a thickness of 3000nm to 6000 nm.

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