KR101146619B1 - High reflection mirror for simultaneously satisfying visible ray and infrared ray region - Google Patents

Abstract

PURPOSE: A high reflection mirror is provided to improve reflexibility by depositing dielectric substance on an aluminum mirror. CONSTITUTION: A high reflection mirror comprises a substrate layer(11), a plating layer(12), a bonding layer(13), a reflection layer(21), a dielectric substance layer(31), a second dielectric substance layer(41), a third dielectric substance layer(51), a fourth dielectric substance layer(61), and a surface layer(70). The substrate layer is made of beryllium. The plating layer is formed on the substrate layer and is made of nickel. The bonding layer is formed on the plating layer and is made of chrome. The reflecting layer is formed on the bonding layer and is made of aluminum. The first dielectric substance layer is formed on the reflecting layer. The second dielectric substance layer is formed on the dielectric substance layer. The third dielectric substance layer is formed on the dielectric substance layer. The fourth dielectric substance layer is formed on the dielectric substance layer. The surface layer is formed on the fourth dielectric substance layer.

Description

High reflection mirror for simultaneously satisfying visible ray and infrared ray region}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection mirror that changes an optical path by reflecting an image signal from the outside at an angle of 45 degrees or more in an imaging system, and more particularly, to an optical mirror that stably transmits image signals in the visible, near infrared, and infrared regions simultaneously.

Recently, a video system for security and surveillance of external objects has been used for security purposes. The imaging system is composed of a window for protecting the optical system by blocking the external environment, a mirror for changing the light path passing through the window by 90 degrees, and an optical lens system for transmitting the sensor.

In addition, the imaging system must be able to identify objects in daytime, nighttime, and in any environment that obscures the field of view, such as fog or clouds. Therefore, the image system needs to receive a wide range of signals from visible and infrared to obtain image information. Can be. In this case, the mirror that transmits the signal by changing the image information by 90 degrees has to reflect both visible light and infrared light, so that visible light and infrared light are separated. The reason is that the visible light and the infrared light have different absorption and transmissive properties, and thus, materials and coating materials constituting the optical system cannot be used at the same time. Accordingly, the visible light optical system and the infrared optical system are separately used.

In general, reflecting mirrors use a lot of aluminum (Al) and silver (Ag). Ag is a material suitable for use because it has a high reflectance characteristics from the visible to the infrared region, but there is a problem that the durability is weak due to easy oxidation or deterioration.

Therefore, the development of an optical mirror capable of transmitting images in the visible and infrared regions at the same time, the development of a mirror having a strong film strength and durability that is exposed to the outside and resistant to shocks and vibrations is urgently needed. By designing coatings for reduced fabrication, there is a need to reduce manufacturing costs by improving manufacturing and processes.

The present invention has been made to solve the above-mentioned problems of the prior art, an object of the present invention to provide an optical mirror capable of simultaneously transmitting an image of the visible light and the infrared region.

Another object of the present invention is to provide a mirror that is exposed to the outside and has a strong film strength and durability against impact or vibration.

Another object of the present invention is to provide a method of manufacturing a mirror that can reduce the cost by improving the manufacturing and process by designing the coating to reduce the two conventional processes to one process.

The present invention to achieve the above object, a substrate layer; A reflective layer formed on the substrate layer; And a plurality of dielectric layers formed on the reflective layer and comprising at least one of YF ₃ and ZnS.

In the present invention, the substrate layer may be made of beryllium (Be) or glass, particularly beryllium (Be).

In the present invention, the reflective layer may be made of aluminum (Al) or silver (Ag), and aluminum (Al) is particularly preferable.

In the present invention, the thickness of the reflective layer is preferably 100 to 300 nm, more preferably 150 to 200 nm.

In the present invention, the dielectric layer preferably includes a first dielectric layer made of YF ₃ , a second dielectric layer made of ZnS, a third dielectric layer made of YF ₃ , and a fourth dielectric layer made of ZnS.

In the present invention, the thickness of the first dielectric layer and the third dielectric layer is preferably 90 to 120 nm, the thickness of the first dielectric layer and the third dielectric layer may be the same or different, and the thickness of the first dielectric layer is It may be smaller than the thickness.

In the present invention, the thickness of the second dielectric layer and the fourth dielectric layer is preferably 60 to 70 nm, the thickness of the second dielectric layer and the fourth dielectric layer may be the same or different, and the thickness of the second dielectric layer is It may be larger than the thickness.

The mirror of the present invention may further include a plating layer formed between the substrate layer and the reflective layer, wherein the substrate layer is made of beryllium (Be), the plating layer is preferably made of nickel (Ni).

The mirror of the present invention may further include a bonding layer formed between the plating layer and the reflective layer, wherein the substrate layer is made of beryllium (Be), the plating layer is made of nickel (Ni), and the bonding layer is chromium (Cr). It is preferable that it consists of).

The mirror of the present invention may further include a surface layer formed on top of the dielectric layer, the surface layer is made of MgF ₂ , the thickness of the surface layer is preferably 50 to 150 nm.

Preferred mirrors according to the present invention include a substrate layer made of beryllium (Be); A plating layer formed on the substrate layer and made of nickel (Ni); A bonding layer formed on the plating layer and made of chromium (Cr); A reflection layer formed on the bonding layer and made of aluminum (Al); A first dielectric layer formed on the reflective layer and made of YF ₃ ; A second dielectric layer formed on the first dielectric layer and formed of ZnS; A third dielectric layer formed on the second dielectric layer and made of YF ₃ ; A fourth dielectric layer formed on the third dielectric layer and made of ZnS; And a surface layer formed on the fourth dielectric layer and made of MgF ₂ .

In addition, the present invention comprises the steps of forming a substrate layer; Forming a reflective layer over the substrate layer; And forming a plurality of dielectric layers including at least one of YF ₃ and ZnS on the reflective layer.

In the mirror manufacturing method of the present invention, each layer may be laminated by vapor deposition, and the vapor deposition may be ion assisted vapor deposition.

In the mirror manufacturing method of the present invention, the thickness of each layer can be adjusted according to the required wavelength range, and in particular, the thicknesses of the plurality of dielectric layers can be formed differently.

Preferred mirror manufacturing method of the present invention comprises the steps of forming a substrate layer made of beryllium (Be); Plating nickel on the substrate layer to form a plating layer and then polishing the plated layer; Depositing chromium (Cr) on the plating layer to form a bonding layer; Depositing aluminum (Al) on the bonding layer to form a reflective layer; Depositing YF ₃ on the reflective layer to form a first dielectric layer; Depositing ZnS on the first dielectric layer to form a second dielectric layer; Depositing YF ₃ on the second dielectric layer to form a third dielectric layer; Depositing ZnS on the third dielectric layer to form a fourth dielectric layer; And depositing MgF ₂ on the fourth dielectric layer to form a surface layer.

The present invention is to change the optical path of the image signal to 90 degrees, visible light region (0.45 to 0.69 ㎛), near infrared region (1.5 to 1.6 ㎛), infrared region (7.6) in the imaging system for external observation, security, surveillance To 12.3 μm) to provide a mirror system for delivering an image.

The Be substrate mirror of the present invention has the following conditions in order to satisfy the high reflection function.

(1) The thin films of YF ₃ and ZnS have a four-layer structure of 90 to 120 nm and 60 to 70 nm in thickness, respectively.

(2) The thin film thickness of Al for high reflectance has a structure deposited at 100 to 300 nm.

In addition, the Be substrate Al mirror of the present invention has the following conditions for strong film strength and durability.

(1) In order to increase the durability of the mirror and the adhesion between Al and Ni, it has a structure of depositing Cr at 10 to 50 nm.

(2) In order to increase the reflectance of the near-infrared region (1.5 to 1.6 µm) and to strengthen the strength of the thin film, the last layer has a structure in which MgF ₂ is deposited to a thin film thickness of 50 to 150 nm.

In addition, the Be substrate Al mirror of the present invention has the following conditions in order to satisfy the high reflectivity function in the multi-band region.

(1) The first dielectric layer and the third dielectric layer made of YF ₃ have different thicknesses.

(2) The second dielectric layer and the fourth dielectric layer made of ZnS have different thicknesses.

In the present invention, by depositing Al on the metal material Be and by depositing a specific dielectric material (YF ₃ and ZnS) on the aluminum mirror, it is possible to increase the reflectance and improve durability, high reflection simultaneously in the visible and infrared region It can give a function and give strong film strength and durability. In addition, manufacturing such mirrors can reduce the production process and achieve assembly efficiency.

In the present invention, a coating of a metal material capable of simultaneously reflecting the visible and infrared regions, which is a multi-band region, that is, 0.45 to 0.69 μm in the visible light region, 1.5 to 1.6 μm in the near infrared region, and 7.6 to 12.3 μm in the infrared region. By manufacturing a thin film with high reflection function, strong film strength and excellent durability in the optical system, it reduces the production process of optical parts that must be manufactured by separating visible light region and near infrared or infrared region, thereby improving productivity and reducing manufacturing cost. Can be obtained.

1 is a block diagram of a conventional mirror.
2 is a block diagram of a mirror according to a preferred embodiment of the present invention.
3 is a photograph of a mirror according to the present invention.
Figure 4 shows an example of applying a mirror according to the present invention.
5 is reflectance data in the visible and near infrared region of the mirror according to the first embodiment of the present invention.
6 is reflectance data in the infrared region of the mirror according to the first embodiment of the present invention.
7 is reflectance data in the visible and near infrared region of the conventional Al mirror.
8 is reflectance data in an infrared region of a conventional Al mirror.
9 shows the change in reflectance according to the thickness of the dielectric thin film.
10 is reflectance data in the visible and near infrared region of the mirror according to the second embodiment of the present invention.
11 is reflectance data in an infrared region of a mirror according to Embodiment 2 of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of a conventional mirror, which is a substrate mirror 10, a reflective layer 20, a first dielectric layer 30, a second dielectric layer 40, a third dielectric layer 50, a fourth dielectric layer from below. It consists of 60.

A typical aluminum mirror is deposited with Al as a reflective layer 20 on a base layer 10 such as glass, and then a dielectric such as SiO ₂ as the first dielectric layer 30 and the third dielectric layer 50, and a second dielectric layer. 40 and the fourth dielectric layer 60 have a structure in which two to four layers of a dielectric thin film such as TiO ₂ are deposited.

Materials such as SiO ₂ and TiO ₂ have excellent durability and chemical resistance as well as optical properties in the visible region, but reflectance is lowered in the infrared region due to the wavelength absorption characteristics of the material, so that images are transmitted simultaneously using the visible and infrared regions. Can not satisfy the function as a mirror of the dragon.

2 is a configuration diagram of a mirror according to a preferred embodiment of the present invention, wherein the substrate layer 11, the plating layer 12, the bonding layer 13, the reflective layer 21, and the first dielectric layer are provided from below the mirror according to this embodiment. (31), the second dielectric layer 41, the third dielectric layer 51, the fourth dielectric layer 61, and the surface layer 70.

The substrate layer 11 may be made of a metal material or glass such as Be, and in particular, it is preferable to use Be, which is a light and shock resistant metal material, for strong and fast response to external shock or vibration.

The plating layer 12 is applied to improve optical properties, corrosion resistance, abrasion resistance and surface roughness. In particular, since Be used as the substrate layer 11 is toxic and difficult to directly polish, it is preferable to plate a metal material thereon in the first step.

Ni is preferable as the metal material used for the plating layer 12. According to a preferred embodiment of the present invention, the substrate layer 11 is preferably made of Be, and the plating layer 12 is preferably made of Ni.

In addition, after plating on the surface of the substrate layer 11, it is possible to improve the uniformity and flatness through fine polishing to provide a high reflectance in the visible light region and the infrared region, that is, multi-band region.

A binding layer 13 is applied to increase the adhesion between the plating layer 12 and the reflective layer 21.

As the material of the bonding layer 13, Cr having excellent adhesion to both the Al reflection layer 21 and the Ni plating layer 12 is preferable. As such, it is possible to improve durability by increasing the adhesion between Ni and Al using Cr.

The bonding layer 13 is preferably deposited at 10 to 50 nm to increase the durability of the mirror and the adhesion between Al and Ni.

The reflective layer 21 may be made of Al or Ag. In particular, it is preferable to deposit Al in order to obtain high reflectance in the multi band region of the visible light region and the infrared region (1.54 μm, 8 to 12 μm).

In order to satisfy the high reflectivity, the thickness of the reflective layer 21 is preferably 100 to 300 nm, more preferably 150 to 200 nm.

The dielectric layers 31, 41, 51, and 61 not only protect the reflective layer 21 from the external environment, but also increase the reflectance of a specific region.

The dielectric layers 31, 41, 51 and 61 are preferably composed of a plurality of layers, for example, two or more layers, preferably four or more layers.

As the dielectric, a combination of YF ₃ and ZnS is used to increase the reflectance in the visible region (0.45 to 0.69 µm) and at the same time to increase the reflectance in the near infrared region (1.5 to 1.6 µm) and the infrared region (7.6 to 12.3 µm). It is preferable. YF ₃ is a low refractive index material, and ZnS is a high refractive index material.

The dielectric layers 31, 41, 51, and 61 are preferably laminated with alternating YF ₃ and ZnS. In particular, the first dielectric layer 31 and the third dielectric layer 51 are composed of YF ₃ , and the second dielectric layer 41 ) And the fourth dielectric layer 61 are preferably composed of ZnS.

The thickness of the first dielectric layer 31 and the third dielectric layer 51 is preferably 90 to 120 nm, and the thickness of the second dielectric layer 41 and the fourth dielectric layer 61 is preferably 60 to 70 nm.

9 shows the change in reflectance according to the thickness of the dielectric thin film, and shows the change in reflectance according to the wavelength when the thickness of the dielectric thin film is thick and thin.

In FIG. 9, the solid line has a thickness range according to the present invention, the dotted line is a case where the thin film thickness is too thick, and the dashed line is a case where the thin film thickness is too thin.

According to FIG. 9, when the thickness of the dielectric thin film becomes thick, the wavelength of the visible light region is shifted in the infrared direction, so that the reflectance of the blue (450 to 500 nm) and green (500 to 570 nm) regions is reduced, thereby reducing the color representation of the image. Falls.

On the contrary, when the thickness of the dielectric film is thin, the wavelength of the visible light region is shifted in the ultraviolet direction, making it difficult to realize red color (610 to 700 nm).

For this reason, the thin film thickness of ZnS should be in the range of 60 to 70 nm and the thin film thickness of YF ₃ should be in the range of 90 to 120 nm.

The thicknesses of the first dielectric layer 31 and the third dielectric layer 51 may be the same, and the thicknesses of the second dielectric layer 41 and the fourth dielectric layer 61 may be the same.

In addition, the thickness of the first dielectric layer 31 and the third dielectric layer 51 may be different from each other in order to increase the reflectance of the near-infrared region having a relatively low reflectance characteristic compared to the reflectance of the visible or infrared region. The thicknesses of the dielectric layer 41 and the fourth dielectric layer 61 may also be different. In this case, the thickness of the first dielectric layer 31 may be smaller than the thickness of the third dielectric layer 51, and the thickness of the second dielectric layer 41 may be larger than the thickness of the fourth dielectric layer 61.

The surface layer 70 is applied to the uppermost layer to increase the strength of the thin film while increasing the reflectance of the near infrared region.

The surface layer 70 is preferably made of a high hardness material such as MgF ₂ .

The thickness of the surface layer 70 is preferably 50 to 150 nm. The surface layer 70, in particular MgF ₂ , is too thin, the strength of the thin film is weak, too thick may cause cracking due to the stress of MgF ₂ , and also reflectance decrease due to absorption of the thin film in the infrared region of 8 ㎛ or more Occurs. For this reason the suitable thickness of the surface layer 70, in particular MgF ₂ , is 50 to 150 nm.

Preferred mirrors according to the invention consist of a Be substrate layer, Ni plating layer, Cr bonding layer, Al reflecting layer, YF ₃ first dielectric layer, ZnS second dielectric layer, YF ₃ third dielectric layer, ZnS fourth dielectric layer, MgF ₂ surface layer from below do.

Mirrors of this preferred configuration can be made as follows.

First, using a lightweight, impact-resistant Be substrate on the Ni plating in the first step to improve the properties and polishing thereon, and then finely polish the surface to increase the flatness.

Next, after coating Cr on the Ni plating layer to improve adhesion, Al is deposited as a reflective layer to obtain high reflectance in the multi-band region.

Next, in order to simultaneously increase the reflectance of the visible light region, the near infrared region and the infrared region, optical deposition is performed on the Al reflective layer using YF ₃ and ZnS. At this time, preferably, the dielectric thin film is formed in a four-layer structure of the YF ₃ first dielectric layer, the ZnS second dielectric layer, the YF ₃ third dielectric layer, and the ZnS fourth dielectric layer from below.

Finally, MgF ₂ is deposited on the last layer, the surface layer, in order to improve the thin film strength while increasing the reflectance in the near infrared region.

In the mirror manufacturing method of the present invention, the thickness of each layer, which is a thin film, may be appropriately modified according to a required wavelength region, and in particular, the thicknesses of the plurality of dielectric layers may be formed differently. In addition, in order to improve durability of the thin film, it may be manufactured using ion assist deposition (IAD).

In addition, in order to increase the reflectance of the near-infrared region having a relatively low reflectance characteristic compared to the reflectance of the visible or infrared region, the first dielectric layer made of YF ₃ , the third dielectric layer, and the second dielectric layer made of ZnS and the fourth The thickness of the dielectric layer may be deposited differently, and the refractive index of the second dielectric layer and the fourth dielectric layer may be differently produced by varying the IAD conditions during deposition to increase the reflectance.

The high reflectivity mirror of the present invention can be manufactured in the same structure in the glass material in addition to the metal material such as Be.

The mirror manufactured as described above has a high reflectance characteristic from the visible region to the infrared region, so that one mirror can transmit an image signal in the visible region, the near infrared region, and the infrared region, and the dielectric material deposited on the Al thin film. Because of its durability against the external environment, it is suitable for use as a mirror for image transmission of day and night surveillance equipment.

Figure 3 is a photograph of the mirror according to the present invention, showing the shape of the Be stable mirror using a Be substrate.

Figure 4 shows an example of applying a mirror according to the present invention, it shows an example used in the tank. The mirror according to the present invention can be used in imaging systems for external observation, security, and surveillance in addition to military products such as tanks.

Example 1

A mirror having the structure of FIG. 2 was manufactured, and the material and thickness of each layer are shown in Table 1.

material Thickness (nm) Surface layer MgF ₂ 100.00 4th dielectric layer ZnS 65.70 Third dielectric layer YF ₃ 102.40 Second dielectric layer ZnS 65.70 First dielectric layer YF ₃ 102.40 Reflective layer Al 200.00 Bonding layer Cr 20.00 Plating layer Ni - Substrate layer Be -

[Example 2]

A mirror having the structure of FIG. 2 was manufactured, and the material and thickness of each layer are shown in Table 2.

material Thickness (nm) Surface layer MgF ₂ 100.00 4th dielectric layer ZnS 67.44 Third dielectric layer YF ₃ 114.69 Second dielectric layer ZnS 68.07 First dielectric layer YF ₃ 98.31 Reflective layer Al 200.00 Bonding layer Cr 20.00 Plating layer Ni - Substrate layer Be -

Comparative Example 1

A mirror having the structure of FIG. 1 was manufactured, and the material and thickness of each layer are shown in Table 3.

material Thickness (nm) 4th dielectric layer TiO ₂ 63.01 Third dielectric layer SiO ₂ 99.40 Second dielectric layer TiO ₂ 63.01 First dielectric layer SiO ₂ 99.40 Reflective layer Al 200.00 Substrate layer Glass -

5 is reflectance data in the visible and near infrared region of the mirror according to the first embodiment of the present invention, Figure 6 is reflectance data in the infrared region of the mirror according to the first embodiment of the present invention, Figure 7 is a conventional Al Reflectance data in the visible and near infrared regions of the mirror (Comparative Example 1), and FIG. 8 shows reflectance data in the infrared region of the conventional Al mirror (Comparative Example 1).

In contrast to the reflectance data of FIGS. 5 to 8, it can be seen that the reflectance of the mirror according to the present invention is increased in the visible and near infrared region, particularly in the region of 800 to 900 nm, compared with the conventional Al mirror.

In particular, in the infrared region, the conventional Al mirror had a very low reflectance near 8,000 nm, but the mirror of the present invention showed excellent reflectance in all infrared wavelength regions.

10 is reflectance data in the visible and near infrared region of the mirror according to the second embodiment of the present invention, Figure 11 is reflectance data in the infrared region of the mirror according to the second embodiment of the present invention, the solid line in the figure Example 1 and the dotted line are Example 2.

10 and 11, the reflectance in the infrared region (FIG. 11) shows little difference between the two embodiments, but the reflectance in the near infrared region (FIG. 10) increases in the modified structure (Example 2). Able to know.

10, 11: substrate layer
12: plating layer
13: bonding layer
20, 21: reflective layer
30, 31: first dielectric layer
40, 41: second dielectric layer
50, 51: third dielectric layer
60, 61: fourth dielectric layer
70: surface layer

Claims (27)

A substrate layer made of beryllium (Be);
A plating layer formed on the substrate layer and made of nickel (Ni);
A bonding layer formed on the plating layer and made of chromium (Cr);
A reflection layer formed on the bonding layer and having a thickness of 100 to 300 nm made of aluminum (Al);
A first dielectric layer formed on the reflective layer and having a thickness of 90 to 120 nm formed of YF ₃ ;
A second dielectric layer formed on the first dielectric layer and having a thickness of 60 to 70 nm formed of ZnS;
A third dielectric layer formed on the second dielectric layer and having a thickness of 90 to 120 nm formed of YF ₃ ;
A fourth dielectric layer formed on the third dielectric layer and having a thickness of 60 to 70 nm formed of ZnS; And
A mirror for an imaging system, formed on the fourth dielectric layer and including a surface layer having a thickness of 50 to 150 nm made of MgF ₂ .
delete delete delete delete delete The method of claim 1,
A mirror for an imaging system, wherein the thicknesses of the first dielectric layer and the third dielectric layer are the same.
The method of claim 1,
And the thicknesses of the first dielectric layer and the third dielectric layer are different from each other.
The method of claim 1,
And the thickness of the first dielectric layer is smaller than the thickness of the third dielectric layer.
delete The method of claim 1,
A mirror for an imaging system, wherein the thicknesses of the second dielectric layer and the fourth dielectric layer are the same.
The method of claim 1,
A mirror for an imaging system, wherein the thicknesses of the second dielectric layer and the fourth dielectric layer are different from each other.
The method of claim 1,
And the thickness of the second dielectric layer is greater than the thickness of the fourth dielectric layer.
delete delete delete delete delete delete delete delete Forming a substrate layer made of beryllium (Be);
Plating nickel on the substrate layer to form a plating layer and then polishing the plated layer;
Depositing chromium (Cr) on the plating layer to form a bonding layer;
Depositing aluminum (Al) on the bonding layer to form a reflective layer having a thickness of 100 to 300 nm;
Depositing YF ₃ on the reflective layer to form a first dielectric layer having a thickness of 90 to 120 nm;
Depositing ZnS on the first dielectric layer to form a second dielectric layer having a thickness of 60 to 70 nm;
Depositing YF ₃ on the second dielectric layer to form a third dielectric layer having a thickness of 90 to 120 nm;
Depositing ZnS on the third dielectric layer to form a fourth dielectric layer having a thickness of 60 to 70 nm; And
And depositing MgF ₂ on the fourth dielectric layer to form a surface layer having a thickness of 50 to 150 nm.
delete The method of claim 22,
Deposition is a method of manufacturing a mirror for an imaging system, characterized in that the ion assisted deposition.
delete The method of claim 22,
A method of manufacturing a mirror for an imaging system, characterized in that the thickness of the plurality of dielectric layers are formed differently.
delete

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