TW201833629A - Anti-halo low warpage optical low pass filter - Google Patents

Abstract

An anti-halo low warpage optical low pass filter includes a base plate having a first surface and a second surface opposite the first surface, a IR-cut and a UV-cutVis AR, the IR-cut is plated on the first surface and has a plurality of first films, the number of layers of the first films is between 27 and 31 layers, the thickness of the IR-cut is between 2 and 4 microns ([mu]m), the UV-cutVis AR is plated on the second surface and has a plurality of second films, the number of layers of the second films is between 17 and 23 layers, the thickness of the UV-cutVis AR is between 0.8 and 1.5 microns ([mu]m), so as to achieve the anti-halo effect and to reduce the warpage of the optical low pass filter after forming.

Description

Anti-halation low warp optical low pass filter

The invention relates to a filter, in particular to an optical low pass filter (OLPF) which is resistant to halation and low warpage.

With the rapid development of science and technology, digital imaging products are widely welcomed by consumers, and thin and light is already a mainstream development in the market. The Blue Glass used in the low-pass filter on the CMOS sensor on digital imaging products will be developed in a lighter and thinner direction. At the same time, the low-pass filter-blue glass filter can effectively filter the infrared rays and restore the true color of the object, further greatly improving the photographic quality.

Referring to Fig. 1A, the state of the optical low pass filter 10 mounted in front of the CMOS photosensitive element 100 of the digital image product is shown. The optical low-pass filter 10 of the prior art is mainly composed of a substrate 11 and a UV-IR cut 12 (or IR-cut) 14 plated on the first surface 111 of the substrate 11. And an anti-reflection film (ARC) 13 (or UV-cut 15) is plated on the second surface 112 of the substrate 11. However, the current designs of optical low-pass filters still have their own drawbacks, as explained below:

Referring to Figure 1B, a schematic diagram of a conventional optical low pass filter is shown. The UV-IR cut film (UV-IR cut) disposed on a surface of the substrate 11 is between about 38 layers and 45 layers, and the film layer has a thickness of about 3.8 μm to 4.5 μm. The number of layers of the anti-reflection film (ARC) 13 on the other surface of the substrate 11 is between about 4 and 7 layers, and the thickness of the film layer is between 0.25 μm and 0.5 μm. Such a structural design will make both surfaces of the substrate 11 The difference in the thickness of the plating is too large, and the tensile stress or compressive stress causes the optical low-pass filter 10 to warp. Especially on both sides of the optical low-pass filter 10, the warpage is more obvious, which is unfavorable. Processing, application.

Referring to Figure 1C, a schematic diagram of another optical low pass filter is shown. The infrared cut-off film (IR-cut) 14 disposed on a surface of the substrate 11 is between about 19 and 23 layers, and the film layer has a thickness of about 2.5 μm to 3.5 μm, and is disposed on the substrate 11 A UV-cut 15 layer on a surface is between about 17 and 23 layers, and the thickness of the film is between about 2.0 μm and 2.5 μm. Such a structural design can eliminate the stress and reduce the optical low. The warpage after the filter is formed, however, when the optical low-pass filter is designed with a UV-cut film 15, when the incident angle of the light is increased, the UV-cut film 15 The reflectance is improved, and it is easy for the CMOS photosensitive element to produce lens flare, that is, halo, as shown in FIG. 1D, showing the reflection spectrum of the ultraviolet cut film (UV-cut) at 0 degree, which is displayed in the visible light range. (The wavelength is between 415 ± 10 and 685 ± 10), the UV-cut does not cause significant light reflectivity, however, the UV-cut is shown in Figure 1E. The reflectance spectrum at 50 degrees is shown in the visible range (wavelength between 415 ± 10 and 685 ± 10), the UV cut-off film (U V-cut) causes significant light reflectance between 480 and 530 nanometers (nm), up to 40%, which in turn produces halo.

Therefore, how to develop an optical low-pass filter that is resistant to halation and low warpage, which solves the above problem is the creative motive of the present invention.

It is an object of the present invention to provide an optical low pass filter that is resistant to halation and low warpage.

In order to achieve the foregoing object, an anti-halation low warpage optical low-pass filter according to the present invention includes: a substrate having a first surface and a second surface opposite to the first surface An infrared cut-off film (IR-cut) is plated on the first surface and has a plurality of first film layers, and the first film layer number is between 27 and 31 layers, and the thickness of the infrared cut film Between 2 and 4 micrometers (μm); a UV-cut Vis AR, plated on the second surface, and having a plurality of second layers, and the second layer The number is between 17 and 23 layers, and the ultraviolet cut-off visible light anti-reflection film has a thickness of between 0.8 and 1.5 micrometers (μm).

Preferably, the substrate is an optical glass.

Preferably, the infrared cut-off film (IR-cut) is formed by staggering a first film layer of a high refractive index material and a first film layer of a low refractive index material, the ultraviolet cut-off visible light anti-reflection film ( The UV-cut Vis AR) is formed by stacking a second film layer of a high refractive index material and a second film layer of a low refractive index material.

Preferably, the initial film stack before the infrared cut-off film (IR-cut) simulation optimization is 0.5H 1.2 (.5L H .5L)^7 1.5 (.5L H .5L)^7, and the center wavelength is 650 nm. Meter (nm); wherein H represents a first film layer of a high refractive index material having a thickness of a quarter wavelength, L represents a first film layer of a low refractive index material having a thickness of a quarter wavelength, H or The number in front of L indicates the magnification, which will be adjusted according to the refractive index of the material used.

Preferably, the initial film stack before the simulation optimization of the UV-cut Vis AR is (.5H L 0.5H)^14, and the center wavelength is 340 nm (nm); wherein H The thickness of the second film layer indicating the thickness of the high refractive index material having a thickness of a quarter wavelength, L indicating the thickness of the low refractive index material having a thickness of a quarter wavelength, and the numerical value indicating the front of H or L are used according to the use. The refractive index of the material will be adjusted differently.

Preferably, the first film layer of the high refractive index material is titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), or tantalum pentoxide (Nb2O5), which is the first film layer of the low refractive index material. It is cerium oxide (SiO2) or magnesium fluoride (MgF2).

Preferably, the second film layer of the high refractive index material is titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), or tantalum pentoxide (Nb2O5), which is the second film layer of the low refractive index material. It is cerium oxide (SiO2) or magnesium fluoride (MgF2).

Accordingly, the present invention has an infrared cut-off film (IR-cut) and an ultraviolet cut-off visible light anti-reflection film (UV-cut Vis AR) which are respectively plated on both surfaces of the substrate, and the infrared cut-off film (IR-cut) The thickness is close to the thickness of the UV-cut Vis AR, and the number of the first film layer of the IR-cut is between 27 and 31 layers and the ultraviolet cut-off visible light The second film layer of the anti-reflective film (UV-cut Vis AR) is between 17 and 23 layers to achieve anti-halation and reduce the warpage after the optical low-pass filter is formed.

The present invention has been described in connection with the preferred embodiments of the present invention in accordance with the accompanying drawings.

Referring to FIG. 2, an embodiment of the present invention provides an anti-halation low warpage optical low-pass filter, which mainly comprises a substrate 20, an infrared cut-off film (IR-cut) 30, and an ultraviolet cut-off. A combination of visible light antireflection film (UV-cut Vis AR) 40, wherein:

The substrate 20 has a first surface 21 and a second surface 22 opposite to the first surface 21; in this embodiment, the substrate 20 is an optical glass or other light transmissive substrate, but limit.

The infrared cut-off film (IR-cut) 30 is plated on the first surface 21 of the substrate 20 and has a plurality of first film layers 31, 32, and the number of the first film layers 31, 32 is between 27 and 31. Between the layers, the thickness of the infrared cut film 30 is between 2 and 4 micrometers (μm); in this embodiment, the number of layers of the first film layers 31, 32 of the infrared cut film (IR-cut) 30 is 30. The infrared cut film 30 has a thickness of 3.5 micrometers (μm), and the infrared cut film (IR-cut) is a first film layer 31 which is a high refractive index material and a first film layer which is a low refractive index material. 32 are staggered and stacked, do not include the first layer of buffer layer (not shown), the singular layer is titanium dioxide (TiO ₂ ), and the double layer is cerium oxide (SiO ₂ ), but not limited thereto. The first film layer 31 which is a high refractive index material may also be tantalum pentoxide (Ta2O5) or tantalum pentoxide (Nb2O5), and the first film layer 32 which is a low refractive index material may also be fluorinated. Magnesium (MgF2). In addition, the initial film stack before the IR-cut 30 simulation optimization is 0.5H 1.2 (.5L H .5L)^7 1.5 (.5L H .5L)^7, and the center wavelength is 650 nm. (nm); wherein H represents a first film layer of a high refractive index material having a thickness of a quarter wavelength, and L represents a first film layer of a low refractive index material having a thickness of a quarter wavelength, H or L The previous number indicates the magnification, which will vary depending on the refractive index of the material used. ;

The ultraviolet cut-off visible light anti-reflection film (UV-cut Vis AR) 40 is plated on the second surface 22 of the substrate 20 and has a plurality of second film layers 41 and 42 and the number of the second film layers 41 and 42 Between 17 and 23 layers, the ultraviolet cut-off visible light anti-reflective film 40 has a thickness of between 0.8 and 1.5 micrometers (μm). In this embodiment, the number of layers of the second film layers 41 and 42 of the UV-cut Vis AR 40 is 19, and the UV-cut Vis AR 40 is used. The thickness is 1.3 micrometers (μm), and the ultraviolet cut-off visible light anti-reflection film (UV-cut Vis AR) 40 is composed of a second film layer 41 which is a high refractive index material and a second film layer 42 which is a low refractive index material. Interleaved stacking, does not include the first layer of buffer layer (not shown), the singular layer is titanium dioxide (TiO ₂ ), the double layer is cerium oxide (SiO ₂ ), but not limited to this, which is high The second film layer 41 of the refractive index material may also be tantalum pentoxide (Ta 2 O 5 ) or tantalum pentoxide (Nb 2 O 5 ), and the second film layer 42 which is a low refractive index material may also be magnesium fluoride ( MgF2). In addition, the UV-cut Vis AR 40 simulates an initial film stack (.5H L 0.5H)^14 with a center wavelength of 340 nm (nm); where H is the thickness The thickness of the second film layer of a high refractive index material having a thickness of one quarter wavelength, L means a low refractive index material having a thickness of a quarter wavelength, and the numerical value of the front of H or L is expressed according to the material used. The refractive index will be adjusted differently.

The above description is the structure and configuration description of each main component of the embodiment of the present invention. In this way, the creation can at least achieve the following effects.

The infrared cutoff film (IR-cut) 30 and the ultraviolet cut visible light antireflection film (UV-cut Vis AR) 40 are respectively plated on the first surface 21 and the second surface 22 of the substrate 20, and the present invention The number of layers of the first film layers 31, 32 of the infrared cut film (IR-cut) 30 is 30, and the thickness of the infrared cut film 30 is 3.5 micrometers (μm), and the ultraviolet cut-off visible light anti-reflection film (UV-cut Vis) The number of layers of the second film layers 41, 42 of the AR) 40 is 19, and the thickness of the UV-cut Vis AR 40 is 1.3 micrometers (μm), thereby achieving anti-halation and reducing the optics. The warpage of the low-pass filter after forming.

Referring to FIG. 3, the reflection spectrum of the ultraviolet cut visible light antireflection film (UV-cut Vis AR) of the present invention at 0 degree is shown, which is displayed in the visible light range (wavelength is between 415±10 and 650±10). UV-cut Vis AR does not cause significant light reflectance, even at 0%, and the reflectance spectrum of the present invention and the conventional UV-cut at 0 degrees (as shown in Figure 1D) is better or the same.

Referring to FIG. 4, the reflection spectrum of the ultraviolet cut visible light antireflection film (UV-cut Vis AR) of the present invention at 50 degrees is shown, which is displayed in the visible light range (wavelength is between 415±10 and 650±10). The ultraviolet cut-off visible light anti-reflection film (UV-cut Vis AR) does not cause significant light reflectance, and even the light reflectance is below 5%. Therefore, the present invention can achieve anti-halation purposes. In contrast, the UV-cut is a reflection spectrum at 50 degrees (as shown in FIG. 1E), which is known to have a wavelength of 480 to 530 nanometers (nm). Between the two, it will cause obvious light reflectivity, up to 40%, which will produce halo phenomenon. Therefore, the present invention can achieve anti-halation and is not easy to cause lens glare to the photosensitive element.

It is to be noted that the number of layers of the first film layers 31 and 32 of the infrared cut film (IR-cut) 30 is 30, and the thickness of the infrared cut film 30 is 3.5 micrometers (μm). The number of layers of the second film layers 41, 42 of the ultraviolet cut-off visible light anti-reflective film (UV-cut Vis AR) 40 is 19, and the thickness of the ultraviolet cut-off visible light anti-reflective film (UV-cut Vis AR) 40 is 1.3 micrometers (μm) In addition to achieving structural anti-halation and reducing the warpage of the optical low-pass filter after forming, the present invention can also achieve the effect of light transmittance. For example, as shown in FIG. 5, a graph of the light transmission spectrum function of the ultraviolet cut-off visible light anti-reflection film (UV-cut Vis AR) at 0 degrees is shown, and it can be seen from the figure that the ultraviolet cut-off visible light anti-reflection film (UV) -cut Vis AR) 100% penetration in the visible range (wavelength between 415 ± 10 and 685 ± 10). For example, as shown in FIG. 6, a graph of the light transmission spectrum function of the infrared cut-off film (IR-cut) at 0 degrees is shown. It can be seen from the figure that the infrared cut-off film (IR-cut) is in the visible light range (wavelength). The penetration between 415 ± 10 and 685 ± 10) is still as high as 100%.

In the above, the above embodiments and the drawings are only the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and the equivalent changes and modifications according to the scope of the present invention should be The scope of the invention is covered.

[知知]
100‧‧‧Photosensitive elements
10‧‧‧Optical low-pass filter
11‧‧‧Substrate
111‧‧‧ first surface
112‧‧‧ second surface
12‧‧‧UV-IR-cut
13‧‧‧Anti-reflective film (ARC)
14‧‧‧Infrared cut-off film (IR-cut)
15‧‧‧UV cut-off film (UV-cut)
[this invention]
20‧‧‧Substrate
21‧‧‧ first surface
22‧‧‧ second surface
30‧‧‧Infrared cut-off film (IR-cut)
31, 32‧‧‧ first film
40‧‧‧UV cut-off anti-reflective film (UV-cut Vis AR)
41, 42‧‧‧ second film

1A is a schematic view of a conventional optical low pass filter and a photosensitive element. Figure 1B is a schematic illustration of a conventional optical low pass filter. 1C is a schematic diagram of a conventional second optical low pass filter. FIG. 1D is a graph showing a reflectance spectrum function of a UV-cut of a conventional second optical low-pass filter at 0 degrees. FIG. 1E is a graph showing a reflectance spectrum function of a UV-cut of a conventional second optical low-pass filter at 50 degrees. Figure 2 is a schematic illustration of an embodiment of the invention. 3 is a graph showing a reflectance spectrum function of an ultraviolet cut-off visible light antireflection film (UV-cut Vis AR) at 0 degrees according to an embodiment of the present invention. 4 is a graph showing a reflectance spectrum function of an ultraviolet cut-off visible light antireflection film (UV-cut Vis AR) at 50 degrees according to an embodiment of the present invention. Fig. 5 is a graph showing a light transmission spectrum function of an ultraviolet cut-off visible light antireflection film (UV-cut Vis AR) at 0 degree according to an embodiment of the present invention. 6 is a graph showing a light transmission spectrum function of an infrared cut film (IR-cut) at 0 degrees according to an embodiment of the present invention.

Claims (7)

An anti-halation low warpage optical low-pass filter comprising: a substrate having a first surface and a second surface opposite to the first surface; an IR-cut, plating On the first surface, and having a plurality of first film layers, and the number of the first film layer is between 27 and 31 layers, and the thickness of the infrared cut film is between 2 and 4 micrometers (μm); a UV-cut Vis AR is plated on the second surface and has a plurality of second film layers, and the second film layer is between 17 and 23 layers, and the ultraviolet cutoff The visible light antireflection film has a thickness of between 0.8 and 1.5 micrometers (μm). The anti-halation low warpage optical low-pass filter of claim 1, wherein the substrate is an optical glass. The anti-halation low warpage optical low-pass filter according to claim 1, wherein the infrared cut film (IR-cut) is a first film layer of a high refractive index material and a low refractive index material. A film layer is stacked in a staggered manner, and the UV-cut Vis AR is interleaved by a second film layer of a high refractive index material and a second film layer of a low refractive index material. to make. The anti-halation low warpage optical low-pass filter according to claim 3, wherein the initial film stack before the infrared cut-off film (IR-cut) simulation optimization is 0.5H 1.2 (.5L H .5L)^ 7 1.5 (.5L H .5L)^7, the center wavelength is 650 nanometers (nm); where H represents the first film layer of high refractive index material having a thickness of a quarter wavelength, and L represents a thickness of four points The number in front of the first film layer, H or L of the low refractive index material of one wavelength thickness indicates the magnification. The anti-halation low warpage optical low-pass filter according to claim 3, wherein the UV-cut Vis AR is optimized before the simulation of the initial film stack is (.5H L 0.5H) ^14, the center wavelength is 340 nm (nm); wherein H represents the thickness of the second film layer of the high refractive index material having a thickness of a quarter wavelength, and L represents the thickness of the thickness of the quarter wave The refractive index material, the number before H or L, represents the magnification. The anti-halation low warpage optical low-pass filter according to claim 3, wherein the first film layer of the high refractive index material is titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), or pentoxide Niobium (Nb2O5), the first film layer which is a low refractive index material is cerium oxide (SiO2) or magnesium fluoride (MgF2). The anti-halation low warpage optical low-pass filter according to claim 3, wherein the second film layer of the high refractive index material is titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), or pentoxide. The second film of Nb2O5, which is a low refractive index material, is cerium oxide (SiO2) or magnesium fluoride (MgF2).