JPH09156964A - Light-absorptive reflection-preventing body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a reflection-preventing body having an appropriate optical absorption ratio and reflection-preventing function and excellent in heat resistance at a low cost by forming both the optical absorption membrane and the silica membrane on a base material under specific conditions, whose thicknesses are each controlled in a specified range. SOLUTION: This reflection-preventing body is produced by forming an optical absorption membrane 11 and a silica membrane 13 on a base material (e.g. a glass substrate) 10 in this serial order from the base material 10 side, and this structure enables the reduction of the reflection of incident light from the silica membrane 13 side. In this reflection-preventing body, the thickness of the optical absorption membrane 11 is made 5-25nm and that of the silica membrane 13 is 70-110nm. The optical absorption ratio of the incident light from the silica membrane 13 side of the preventing body is preferably 10-35%. The optical absorption membrane 11 is preferably a membrane mainly containing a nitride of one metal or more selected from among Ti, Zr and Hf.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a light-absorbing antireflection body.

[0002]

2. Description of the Related Art In recent years, with the rapid spread of computers, in order to improve the working environment of terminal operators, it has been required to reduce the reflection on the display surface and to prevent the surface of a CRT (cathode ray tube) from being charged. In addition, recently, in order to improve the contrast, it has been required to reduce the transmittance of the panel glass and shield electromagnetic waves of extremely low frequency that affect the human body.

[0003] As a method for meeting these demands,
(1) providing a conductive anti-reflection film on the panel surface;
(2) A conductive antireflection film is provided on the surface of a face plate for a display screen such as a CRT and the resin is attached to the panel surface. (3) A filter glass having a conductive antireflection film on both sides is attached to the front surface of the cathode ray tube. It has been adopted such as installing in.

In the cases (2) and (3) of these, it is general to form a multilayer antireflection film by a vacuum deposition method. As a specific example of the film structure, for example, Japanese Patent Laid-Open No. Sho 60
For example, those disclosed in Japanese Patent Publication No. 168102 can be cited. The publication describes that an antireflection film is formed by combining a low refractive index dielectric film, a high refractive index dielectric film, and a high refractive index conductive film. By coating the surface with a multilayer antireflection film having these film configurations, the luminous reflectance of the surface is 0.3% or less and the sheet resistance of the surface is 1 k.
Ω / □ or less, and the above electromagnetic wave shielding effect can be imparted.

Further, it is known that it is effective to use an absorbing film as a part of the constitution as a method for increasing the contrast. For example, Japanese Patent Laid-Open No. 64-707
Japanese Patent Laid-Open No. 01-101 discloses an example in which a 4 nm-thickness stainless film, a 29 nm-thickness titanium oxide film, and a 95 nm-thickness silica film are sequentially formed on a glass substrate by a vacuum deposition method. By coating the surface with a multilayer absorptive antireflection film, the luminous reflectance of the surface can be 0.3% or less and the sheet resistance value of the surface can be 1 kΩ / □ or less.
At the same time, the visible light transmittance is reduced by several tens of percent, and high contrast can be achieved.

On the other hand, with regard to the method (1), there are (a) a case where a panel is coated and then formed into a cathode ray tube, and (b) a case where a cathode ray tube is formed and then surface coating is performed. In the present situation, the so-called wet method such as spin coating is also used.

In the case of the so-called dry method such as the above-mentioned vacuum deposition method, in the case of (a), the film characteristics are changed by the heat treatment in the cathode ray tube forming step after film formation, and the desired performance cannot be obtained. In addition, in the case of (b), it is necessary to install the entire cathode ray tube in the vacuum chamber, so that there is a volume and weight limitation and handling is difficult.

Further, in the sputtering method which is a typical dry film forming method, there is a difficulty in forming a high speed stable film of SiO ₂ which is an essential low refractive index material for forming an antireflection film. At present, the technology for industrially producing an antireflection film having a large area has not been established.

However, recently, with the advancement of the required characteristics as described above, the following problems have begun to occur in the surface treatment by the wet method. That is, (1) it is more difficult to control the film thickness in the wet method than in the dry method, and reproducibility and uniformity become a problem in the case of a multi-layered film structure of three or more layers having good antireflection performance. (2) realized by the wet method The lower limit of the sheet resistance value so far is up to about 10 ³ kΩ / □ so far, it is sufficient for antistatic, but 1 kΩ / □ required for electromagnetic wave shielding is difficult. (3) Antireflection For example, it is difficult to impart absorbency without impairing performance.

On the other hand, the vapor deposition method has a problem that the film forming cost is considerably higher than that of the wet method in addition to the above-mentioned thermal stability of the film characteristics, and it has been required to realize a cheaper film forming method.

Under these circumstances, as a result of the recent active development of a method for forming SiO ₂ stably and at high speed by a sputtering method, several methods are being realized. For example, MMRS (metal mode reactive sputtering) found in US Pat. No. 4,445,997.
And C-Mag (cyl of US Pat. No. 4,851,095)
indrical magnetron).

As a result, although the antireflection film formed by the sputtering method is becoming a reality, the structure of the antireflection film often conforms to the film structure conventionally formed by the vacuum vapor deposition method. To date, little is known about particularly effective membrane configurations.

The following are known examples of conventional antireflection films. For example, JD Lancourt's "Optical
Thin Films User's Handbook ”(McGRAW-HILL, 1987), page 128, shows a complex refractive index (n
Spectral reflection curves are shown when the absorption film of −ik) = 2-i2 and the transparent film of n = 1.65 are formed in this order with 3 nm and 75.8 nm, respectively.

However, in this case, what is presented is a theoretical calculation value, and the reflection characteristic is such that the reflection becomes zero only at a single wavelength, which is shown by the transparent two-layer film which is the basic constitution of antireflection. , Which is described as being equivalent to a so-called “V coat”, and has a wide wavelength range (for example, 5
It did not exhibit low reflectivity in the range of 00 to 650 nm).

Further, in US Pat. No. 5,091,244, transition metal nitrides are arranged in order from the substrate side as a structure for reducing reflection of incident light from the substrate side (incident light from the side opposite to the film surface side). Material film and transparent film are 6 ~
It is described that the film is formed with a film thickness of 9 nm and 2 to 15 nm.

When a thin absorption film having an appropriate optical constant is formed, the reflectance from the substrate side is lowered, for example, "Thin-Film Optical Filters" HAMacleod, McGRAW-H.
ILL, 2nd Ed., Pp65-66 (1989), and the US Pat. No. 5,091,244 further describes Si.
O ₂ is laminated thinly ( ₂ to 15 nm).

However, this structure has a film thickness designed to reduce reflection from the substrate side. In the case of a multilayer film including an absorption film, the reflection on the front and back surfaces is completely different. Therefore, in this configuration invented to reduce the reflection from the substrate side, the reflectance from the film surface side is about 10% over the visible light region. Yes, low reflection performance cannot be obtained at all.

Further, US Pat. No. 5,091,244 exemplifies a four-layer structure of glass / transition metal nitride / transparent film / transition metal nitride / transparent film as a structure for reducing reflection on the film surface side. There is.

However, the purpose is to reduce the visible light transmittance to 50% or less, and this is realized by dividing the absorption layer into two layers and making the number of layers four or more. However, there was a practical problem in terms of manufacturing cost.

As described above, a film including an absorption film as a constituent element is basically of a two-layer structure, has a low manufacturing cost, and has a low reflectivity in a wide wavelength range with respect to incident light from the film surface side. The composition was previously unknown.

[0021]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the prior art, and has a sufficiently low reflection performance in a wide wavelength range and a sufficient electromagnetic wave shielding capability. It is an object of the present invention to provide an inexpensive light-absorptive antireflection body having a low surface resistance value and an appropriate visible light absorptance for ensuring a high contrast and being excellent in productivity.

[0022]

SUMMARY OF THE INVENTION The present invention is a light-absorbing film formed by forming a light-absorbing film and a silica film on a substrate in this order from the substrate side to reduce reflection of incident light from the silica film side. In the antireflective body, the geometric thickness of the light absorbing film is 5 to
25 nm, and the geometrical thickness of the silica film is 70
Provided is a light-absorbing antireflection body (hereinafter, referred to as a first invention), which has a thickness of up to 110 nm.

The present invention also reduces reflection of incident light from the silica film side, which is formed by forming a light absorbing film, a high refractive index transparent film, and a silica film on the substrate in this order. In the light-absorptive antireflection material, the geometric thickness of the light-absorbing film is 15 to 30 nm, the geometric thickness of the high refractive index transparent film is 10 to 40 nm, and the geometrical shape of the silica film is Provided is a light-absorptive antireflection body (hereinafter, referred to as a second invention), which has a dynamic film thickness of 50 to 90 nm.

Geometric film thickness of the light absorbing film in the first invention (hereinafter, "geometric film thickness" is simply referred to as "film thickness")
Is 5 to 25 nm in order to realize low reflection, and the thickness of the silica film is 70 to 70 nm from the viewpoint of antireflection.
It is important that it is 110 nm. If the film thickness of either layer deviates from this range, sufficient antireflection performance in the visible light region cannot be obtained. In particular, the thickness range of the light absorbing film is preferably 7 to 20 nm because low reflectivity in the visible light region can be realized.

A silica film (preferably having a refractive index of 1.4
The thickness range of the silica film (6 to 1.47) is 80 to
The thickness of 100 nm is preferable because the low reflection wavelength region can be aligned with the center of the visible light region.

It is particularly preferable that the film thickness of silica is more than 80 nm and 85 nm or less. When the film thickness of silica is 80 nm or less, the reflectance on the long wavelength side tends to increase, and
When it exceeds m, the rising of the reflectance on the short wavelength side is shifted to the long wavelength side.

Further, from the viewpoint of heat resistance, the thickness of the light absorbing film in the first invention is preferably 10 to 20 nm. When the film thickness is less than 10 nm, the low reflection performance and surface resistance deterioration at the time of heat treatment are large, and when the film thickness exceeds 20 nm, the heat resistance is improved but the antireflection region is narrowed.

On the other hand, from the viewpoint of low reflection performance after film formation,
The thickness of the light absorption film in the first invention is preferably 7 to 15 nm. When the film thickness is less than 7 nm, the reflectance on the long wavelength side tends to increase significantly, and the film thickness is 1
When it exceeds 5 nm, the low reflection wavelength region becomes narrow.

The thickness of the light absorption film is more than 8 nm and 13 nm.
It is preferably less than 8 nm, and more preferably more than 8 nm and 10 nm or less. When the film thickness of the light absorption film is 8 nm or less, the reflectance on the long wavelength side tends to increase, and when the thickness is 13 nm or more, the rise of the reflectance on the short wavelength side is shifted to the long wavelength side and the reflectance on the long wavelength side changes. The rising edge tends to shift toward the short wavelength side, and the low reflection region tends to become narrow.

The light-absorptive antireflection material of the first invention exhibits excellent antireflection characteristics, but the characteristics may be deteriorated in the heat treatment step in the above-described cathode ray tube molding process. This characteristic change is mainly caused by the oxidation of the light absorption film.

Further, after forming the light absorbing film as the first layer, the light absorbing film may be oxidized when the second layer silica film is formed, and desired characteristics may not be obtained.

Therefore, between the light absorption film and the silica film,
By inserting a layer that prevents oxidation of the light absorption film (hereinafter referred to as an oxidation barrier layer), it is possible to prevent oxidation during film formation,
Heat resistance can be improved.

This type of oxidation barrier layer is widely used in so-called Low-E glass using a silver film, and is described in, for example, US Pat. No. 4,548,691 and JP-A-59-165001. Have been shown to form a barrier layer for the purpose of preventing the silver film from being oxidized during the formation of an oxide film that is subsequently formed on the silver film. Thus, this barrier layer is a thin film formed to prevent the oxidation of another layer formed thereunder, and has no optical meaning.

Various metal films and metal nitride films can be used as the oxidation barrier layer. The film thickness is preferably 20 nm or less so as not to impair the original antireflection performance. Further, if the film thickness of this oxidation barrier layer is less than 1 nm, the improvement of heat resistance becomes insufficient. Therefore, 1
It is preferable to insert an oxidation barrier layer having a film thickness of 20 nm, because heat resistance can be effectively improved.

As described above, the oxidation barrier layer has no optical meaning and is an optically unnecessary layer.
The insertion of this layer may deteriorate the antireflection performance. In particular, when the oxidation barrier layer is light absorbing (for example, light absorbing silicon nitride), the antireflection performance is significantly deteriorated unless the thickness of the oxidation barrier layer is approximately 5 nm or less.

When a transparent oxidation barrier layer is used, the allowable film thickness varies depending on the refractive index of this layer. The maximum allowable film thickness is maximized when a material having a refractive index of about 2.0 (for example, silicon nitride or aluminum nitride) is used, and a barrier layer up to about 20 nm is provided between the lower nitride layer and the upper silica layer. In addition, it can be inserted while maintaining low reflection characteristics.

As the oxidation barrier layer, at least one selected from the group consisting of chromium, molybdenum, tungsten, vanadium, niobium, tantalum, zinc, nickel, palladium, platinum, aluminum, indium, tin and silicon.
It is sufficient to use a film containing one kind of metal as a main component or a film containing these nitrides as a main component, or a film containing at least one metal selected from the group consisting of titanium, zirconium and hafnium as a main component. This is preferable because it is possible to achieve both improvement of antioxidation performance and maintenance of excellent antireflection properties.

In particular, a film containing silicon as a main component or a film containing silicon nitride as a main component has excellent oxidation barrier performance, and when a silica film is formed using a conductive Si target, the target is used. It is advantageous in production in that it is not necessary to increase the material.

The light absorptivity of the light-absorptive antireflection member in the first invention is 1 with respect to visible light incident from the silica film side.
It is desirable to be 0 to 35%. When the light absorptance deviates from this range, the thickness range of the light absorbing film is inappropriate, or the optical constants of the light absorbing film are inappropriate, so that sufficient antireflection performance in the visible light region cannot be obtained. You won't get it.

As the high refractive index transparent film in the second invention, it is preferable to use a material having a refractive index of 1.7 or more. When the refractive index is less than 1.7, the improvement of the antireflection performance due to the insertion of the high refractive index transparent film is hardly seen. As a specific material, for example, Y ₂ O ₃ ,
ZrO ₂ , ZnO, SnO ₂ , Ta ₂ O ₅ , TiO ₂ or the like can be used.

A transparent conductive film such as ITO can also be used. In this case, since the surface resistance is determined by the parallel resistance of the light absorption film layer and the transparent conductive film layer, the resistance can be easily reduced as compared with the case where the conductivity is expressed only by the light absorption film, for example, the titanium nitride film. Become.

The film thickness of the light absorbing film in the second invention is 15 to 30 nm for realizing low reflection, the film thickness of the high refractive index transparent film is 10 to 40 nm, and the film thickness of the silica film is From the viewpoint of antireflection, it is important that the thickness is 50 to 90 nm. If the film thickness of either layer deviates from this range, sufficient antireflection performance in the visible light region cannot be obtained.

Also in the light-absorbing antireflection body of the second invention, an oxidation barrier layer can be provided. In the light absorptive antireflection body of the second invention, the oxidation having a film thickness of 1 to 20 nm is provided between the light absorption film and the high refractive index transparent film or between the high refractive index transparent film and the silica film. A barrier layer can be formed.

As the oxidation barrier layer, the material preferably used in the above-mentioned light-absorbing antireflection body of the first invention is also preferably used.

The light absorptivity of the light absorptive antireflection member in the second invention is 3 with respect to the visible light incident from the silica film side.
It is preferably 0 to 60%. If the light absorption rate deviates from this range, the thickness range of the light absorption film is inappropriate,
Alternatively, the optical constants of the light absorbing film are inappropriate, and thus sufficient antireflection performance in the visible light region cannot be obtained.

Glass or plastic can be used as the substrate in the first and second inventions. In particular, a glass substrate, which constitutes the front surface of the display surface for the display,
A plastic substrate or a plastic film is preferable because the effects of the present invention can be sufficiently exhibited.

Examples of the glass used as the substrate on the front surface of the display include, for example, the panel glass itself constituting the CRT, the face plate glass used by attaching the CRT to the CRT with resin, and the glass installed between the CRT and the operator. The filter glass etc. which are carried out are mentioned. Other examples include the front glass of flat displays such as liquid crystal display panels and plasma display panels.

The plastic used as a substrate or film for the front surface of the display is, for example, 1) a cathode ray tube or a transparent resin such as PET (polyethylene terephthalate) used by being stuck on the front glass of the flat display with a resin. Examples include film-like plastic, 2) transparent plastic as a filter substrate installed between the cathode ray tube and the operator, and 3) a transparent plastic plate forming the front surface of a flat display.

FIG. 17 shows an example of using the light-absorbing antireflection material of the present invention. 17A to 17C show examples in which the light-absorbing antireflection body of the present invention is applied to a CRT, a panel glass, and a plastic film attached to the front surface of the CRT, respectively.

As shown in FIG. 17, the light-absorptive antireflection body of the present invention in which the antireflection film is formed only on the surface of the substrate on the observer side has extremely excellent antireflection properties.
Further, since the antireflection film is directly formed on the surface of the substrate that generates electromagnetic waves, the electromagnetic waves can be shielded very effectively.

When the light-absorbing antireflection body of the present invention is applied to the filter glass, an antireflection film may be formed on the surface of the substrate opposite to the observer.

As the light absorbing film in the first and second inventions, a material that substantially reduces the surface reflectance by the light interference effect with the silica layer formed thereon is used.

Examples of the light absorbing film include at least one metal selected from the group consisting of titanium, zirconium, and hafnium, and a film containing a nitride of the metal as a main component. Among these, titanium, Those containing as a main component a nitride of at least one metal selected from the group consisting of zirconium and hafnium are preferable in view of the dispersion relation of the refractive index and the extinction coefficient in the visible light region. It has the feature of expanding the low reflection area in the light area.

When two or more materials are used for the light absorption film,
1) It may be used as a composite material, and 2) Films made of different materials may be laminated and used so that the total film thickness is 5 to 25 nm.

Further, the film containing titanium nitride as a main component has a value of its optical constant in the visible light region which is well matched with that of the silica film to reduce the reflectance and an appropriate absorption coefficient value. Since the film thickness for obtaining a good light absorptivity is in the range of several nm to several tens of nm, it is particularly preferable in terms of productivity and reproducibility.

In the case where a metal nitride-based film is used as the light absorption film, if the above-mentioned nitride-based film is used as the oxidation barrier layer, the first layer and the oxidation barrier layer are in the same gas atmosphere. The film can be formed by sputtering. This is a great advantage in the case of assuming an actual film-forming equipment by sputtering.

That is, when considering a so-called in-line type sputtering apparatus which is excellent in mass productivity, these light absorption film and the oxidation barrier layer can be formed in the same chamber (referred to as chamber A). Therefore, the chamber for gas separation needs to be provided only between the chamber for forming a silica film, which is subsequently formed in the upper layer, and the chamber A, which is extremely efficient.

In particular, when a film containing titanium nitride as the main component is used as the first layer and silicon nitride is used as the oxidation barrier layer, the effect of improving the adhesion between the titanium nitride film and the outermost silica film is also obtained. . In this case, when both are formed by an in-line sputtering method in which they are formed in the same chamber, the silicon nitride film of the oxidation barrier layer becomes light absorbing under the sputtering gas conditions in which suitable titanium nitride is obtained. In addition, the effect of improving the adhesive force can be obtained similarly.

The light absorbing film in the first and second inventions,
As a method for forming the high refractive index transparent film and the silica film, a general thin film forming means can be adopted. For example, a sputtering method, a vacuum vapor deposition method, a CVD method, a sol-gel method, or the like.

Particularly, in the DC sputtering method, it is relatively easy to control the film thickness, practical film strength can be obtained even when formed on a low temperature substrate, and it is easy to increase the area.
It is preferable to use a so-called in-line type facility from the viewpoint of easy formation of the laminated film. Another advantage is that it is relatively easy to adjust the film forming conditions so that the nitride of titanium, zirconium or hafnium, which is preferable as the light absorbing film, has a preferable optical constant.

In the case of using an in-line type sputtering apparatus, the film thickness distribution in the width direction of conveyance can be adjusted to some extent by setting a mask plate or a magnetic field strength distribution of the cathode magnet. Therefore, when a substrate used for the front surface of the display is used as the substrate, the film thickness of the peripheral portion of the substrate can be set to be slightly thicker than that of the central portion. By providing such a film thickness distribution on the substrate, it is possible to mitigate the phenomenon that the reflected color shifts to yellow or red due to the oblique incident effect of light when viewing the periphery of the screen from the center. preferable.

The substrate heating is essential for the vacuum vapor deposition method,
The drawbacks are that it is difficult to increase the area and that it is relatively difficult to obtain good nitrides, but if it is a relatively small substrate material that can withstand high temperatures, it is the most completed process ever. Is advantageous.

The CVD method requires higher temperature and it is difficult to increase the area in terms of the film thickness distribution, but it is an excellent method for obtaining a good nitride.

The sol-gel method is the wet method described in the section of the prior art and has a track record as a surface treatment technology for cathode ray tubes. It is relatively difficult to obtain a good nitride, and batch processing is performed one by one, but there is a possibility that it will be advantageous in terms of cost in small-quantity production because of small equipment investment.

The light absorbing antireflection film of the present invention can be formed by combining these methods. For example, the light absorption film of the first layer is formed by a sputtering method in which a relatively preferable optical constant is easily obtained, and then the high-refractive-index transparent film and / or the silica film is formed by spin coating by a wet method which is excellent in film formation cost. it can. Similarly, after forming the light absorption film of the first layer by the CVD method, the high refractive transparent film and /
Alternatively, the silica film can be formed by spin coating by a wet method, which is excellent in film forming cost.

In this case, the spin coat solution may erode the light absorbing film already formed as the first layer, and as a result, desired characteristics may not be obtained.
For example, when using a spin coating solution composed of 0.1N hydrochloric acid, tetraethoxysilane and ethyl alcohol, an oxide film or nitride film having good durability is formed as a protective film for the first layer before spin coating. It is preferable to set.

As described above, various methods and combinations thereof can be considered as the method of forming the light-absorbing antireflection film of the present invention (first and second inventions), but the present invention is not limited thereto. .

As the light absorption film containing titanium nitride as a main component (referred to as TiN light absorption film), it is most preferable from the viewpoint of productivity to use a metal titanium target subjected to DC sputtering in the presence of nitrogen gas. preferable.

At this time, in order to keep the optical constant of the TiN light absorbing film in a preferable range, the sputtering gas contains nitrogen and a rare gas as the main components, and the ratio of the nitrogen is 3.
It is preferable to be ˜50% by volume, especially 5 to 20% by volume. If the proportion of nitrogen is smaller than this, the titanium-excessive TiN light absorbing film is formed, and the low reflection wavelength region is narrowed. Further, if the proportion of nitrogen is higher than this, the TiN light absorbing film becomes excessive in nitrogen, the low reflection wavelength region is narrowed, and the specific resistance of the TiN light absorbing film is increased and the surface resistance value is increased.

The power applied to the target is 1 W / cm.
Preferably, the power density is ² or more. This is because the film formation rate is kept high enough for industrial production, and the amount of impurities taken into the TiN light absorption film during film formation is kept low. In particular, as described later, it has a great effect of suppressing the amount of oxygen taken into the film.

The power applied to the target at this time is preferably 10 W / cm ² or less. This is for obtaining a TiN light absorbing film having an appropriate optical constant and avoiding frequent dissolution of the target or cathode and abnormal discharge due to excessive power application to the target. That is, if more electric power is applied, a Ti-rich TiN light absorbing film becomes a Ti-rich light absorption film even in a pure nitrogen atmosphere, a desired composition cannot be obtained, and the target and its peripheral parts are heated to cause arcing or in some cases. Danger of melting of heated parts.

Inclusion of a small amount of impurities in the composition of the target and the sputtering gas causes no problem in the range where the finally formed thin film has substantially the optical constant of the TiN light absorbing film. In addition, a material containing titanium nitride as a main component is used as a target, and Ti is sputtered by sputtering.
An N light absorption film may be formed.

In the TiN light absorbing film, the atomic ratio of nitrogen to titanium in the film is preferably 0.5 to 1.5 from the viewpoint of optical constant and specific resistance. If it is less than 0.5, a titanium nitride film with a slight excess of titanium is formed and the specific resistance is lowered, but the optical constant is unsuitable and the antireflection effect is unsatisfactory. Further, when it is larger than 1.5, a nitrogen-excessive titanium nitride film is formed, and with the change of the optical constant,
Since the specific resistance increases, both reflectance and surface resistance become insufficient.

Particularly, from the viewpoint of antireflection, the atomic ratio of nitrogen to titanium in the film is preferably 0.75 to 1.30.

On the other hand, it has been found that the presence of oxygen improves the adhesion to the oxide substrate or the upper silica film. Therefore, as long as the optical constant of the TiN light absorption film is kept within the preferable range, it may be preferable that the TiN light absorption film contains oxygen.

In this case, the TiN light absorbing film preferably has an atomic ratio of oxygen to titanium in the film of 0.5 or less from the viewpoint of optical constant and specific resistance. If this ratio is larger than 0.5, a titanium oxynitride film is formed,
As the specific resistance increases, the optical constant becomes unsuitable,
Both the surface resistance value and the antireflection effect are insufficient.

When the TiN light absorbing film is formed by the usual sputtering method, it is unavoidable that oxygen is mixed into the film due to the residual gas in the vacuum chamber. The effect of oxygen in the film on the optical properties of the TiN light absorbing film has not been known so far. In particular, the effect on the performance as a light absorbing layer in the present invention was not known at all.

The present inventors have earnestly studied the relationship between the film forming conditions of the TiN light absorbing film and the amount of oxygen in the TiN light absorbing film, and the relationship between the performance as the light absorbing layer in the present invention. From the viewpoint of optical constants, it was found that the atomic ratio of oxygen to titanium in the film is preferably 0.4 or less from the viewpoint of the optical constant.

When this ratio exceeds 0.4, the wavelength dependence of the optical constant of TiN deviates from the preferable range, and as a result, the low reflection property tends to deteriorate. Further, since the oxynitride film is formed, the specific resistance also increases, and the surface resistance tends to exceed 1 kΩ / □ necessary for shielding electromagnetic waves.

Based on the above findings, the present inventors
By selecting the film forming method and film forming conditions for iN,
As shown in Examples described later, when the silica film is formed in the upper layer with an optimum film thickness, the reflectance is 0.
Wavelength region satisfying 6% or less is at least 500 to 650
Ti that realizes a laminated body having a wide range of nm
An N light absorption film could be formed.

As described above, in the present invention, a laminate having extremely excellent low reflection characteristics can be obtained by keeping the optical constant of the TiN light absorbing film to be used within a preferable range.

The optical constants will be described in more detail below.

Conventionally, in a two-layer antireflection film using a transparent film, the reflectance at the design wavelength is made completely zero by selecting the refractive index and the film thickness of each layer according to the refractive index of the substrate. sell. However, at wavelengths other than the design wavelength, the antireflection condition is broken, so that the reflectance rises largely before and after that, so-called "V coat", and the low reflectivity in a wide wavelength range aimed by the present inventors cannot be obtained.

On the other hand, if the absorption film is used as a constituent element,
The parameters of a single film are (n, d) (n:
Refractive index, d: geometrical film thickness) from two (n, k, d)
Since (k: extinction coefficient) is increased to three, and the absorption film has a large wavelength dependence (dispersion) of (n, k), an absorption film having ideal (n, k) wavelength dispersion. It should theoretically be possible to completely reduce the reflectance to zero at any wavelength when the film is formed with a predetermined film thickness when combined with a transparent film laminated thereon.

Here, as an example of theoretical calculation performed by the present inventors, the lower layer has a 15 nm absorption film, and the upper layer has SiO ₂ of 1 nm.
FIG. 16 shows the dispersion relationship of (n, k) required to make the reflectance zero in the entire visible region when the layers are stacked to a thickness of 00 nm. 16A and 16B show the relationship between n and the wavelength, and the relationship between k and the wavelength, respectively.
Find a material with (n, k) as shown in this figure, or
The synthetic anti-reflection film can be realized with a two-layer structure. However, as can be seen from this figure, such a material cannot be realized because there is a wavelength range in which k must take a negative value.

The present inventors searched for a material having an optical constant close to this ideal (n, k), and found that titanium nitride,
It has been found that zirconium nitride and hafnium nitride are candidates.

Further, as a result of various experiments using the sputtering method, by selecting a specific material, a specific film forming condition, or a film thickness, a very excellent low reflection property is obtained in a wide wavelength range. It was found that a two-layer film structure can be obtained.

As the silica film used in the first and second inventions, a conductive silicon target subjected to DC sputtering in the presence of oxygen gas is used.
It is preferable in terms of productivity. At this time, a small amount of impurities are mixed in order to give the target conductivity, but the silica film here includes, in these cases, even if a small amount of impurities are generally contained, it is substantially silica. It should be considered to represent films with approximately the same refractive index.

In DC sputtering of silicon, arcing is induced by charging of the insulating silica film attached to the peripheral portion of the erosion region of the target, the discharge becomes unstable, and the silicon emitted from the arc spot is discharged. Alternatively, silica particles may adhere to the substrate and become defective. In order to prevent this, a method of neutralizing the charge is often adopted by periodically applying a positive voltage to the cathode, and using a silica film formed by these methods improves the stability of the process. It is very preferable from the point. RF sputtering may be used as a film forming method of silica.

The light-absorptive antireflection film of the present invention exhibits excellent antireflection properties, but since the reflectance in the central part of the visible region is particularly low, the reflection color tone ranges from blue to violet. The thicker the silica film, the more blue it is, and the thinner the silica film, the more red it is. Further, as the film thickness of the light absorption film becomes thicker, the color becomes darker, and conversely, when the film thickness of the light absorption film becomes thinner, the color becomes colorless. Therefore, the film thickness may be appropriately adjusted according to the application.

In the present invention, in addition, an additional thin film layer for improving the adhesive force at the interface and adjusting the color tone may be appropriately provided.

Further, an oil repellent organic film containing fluorocarbon may be formed on the outermost layer in order to facilitate wiping when fingerprints are attached to the outermost surface. As a forming method, there are a vapor deposition method, a coating drying method, and the like, and any of them forms an extremely thin film to such an extent that it has no optical influence. By performing these treatments, the antireflection film surface is less likely to be contaminated, and even when it is contaminated, it can be easily wiped off, which is preferable.

In the light absorbing antireflection film of the present invention,
In a wide wavelength range of 500 to 650 nm, it is preferable to appropriately determine the film forming conditions and film thickness of each layer so that the reflectance does not exceed 0.6%. Especially 45
It is preferable that each layer is formed so that the reflectance does not exceed 1.0% at 0 to 650 nm. further,
Each layer is preferably formed so that the reflectance does not exceed 0.6% at 450 to 650 nm.

[0094]

The light-absorptive antireflection material of the present invention absorbs a part of incident light and reduces the transmittance. Therefore, when applied to the front glass of a display, it is incident from the surface and reflected on the surface of the display element side. The intensity of the incoming light beam is reduced, and the contrast between the display light and the background light can be increased to increase the contrast.

The substrate, the light absorption film, the high refractive index transparent film and the silica film in the present invention are the total reflection determined by the reflection Fresnel coefficient of each interface, the phase change amount between each interface and the amplitude attenuation amount in each layer. The rate is set to be sufficiently low in the visible light region.

In particular, the optical constants of the light absorbing film show a dependence different from the dispersion relation (wavelength dependence) in the visible light region of a normal transparent film. Therefore, when the absorbing film material exhibiting an appropriate dispersion relationship is used as the first layer, the low reflection region in the visible light region is widened as compared with the case where the transparent film alone is used. This effect is remarkable when a nitride of at least one metal selected from the group consisting of titanium, zirconium, and hafnium is used as the light absorption film.

Although the principle that the film structure of the present invention realizes low reflection characteristics in a wide wavelength range as shown in Examples described later is still largely unclear, the optical constant of the absorbing thin film in the present invention is large. Is closer to the ideal value than expected. The possible causes are as follows.

1) Since the film thickness is thin, it is not a uniform film in reality, but the optical constants are distributed in the plane or in the thickness direction, and equivalently, the optical constants are closer to ideal.

2) Depending on the specific film forming conditions, a film having a dispersion of optical constants (closer to ideal) which has hitherto been unknown can be obtained.

3) In the process of forming the upper silica film, the upper part of the lower absorption film is partially oxidized to change the substantial optical constant (to a more ideal value).

According to the present invention, by forming a TiN light absorbing film having an optical constant in a preferable range, the TiN light absorbing film having the above-described function and substantially consisting of two layers or three layers and having an extremely excellent low resistance is formed. It is possible to realize a light-absorbing antireflection body having a reflection characteristic.

[0102]

【Example】

[Example 1] Metallic titanium and a specific resistance of 1.2 Ω in a vacuum chamber
cm type N-type silicon (phosphorus-doped single crystal) is set as a target on the cathode, and the vacuum chamber is set to 1 × 10 ⁻⁵ To.
Exhausted to rr. A two-layer film is formed on the soda lime glass substrate 10 installed in the vacuum chamber as follows, and as shown in FIG.
A light-absorptive antireflection body as shown in was obtained.

A mixed gas of argon and nitrogen (20% by volume of nitrogen) was introduced as a discharge gas, and the pressure was 2 × 10 ⁻³ To.
The conductance was adjusted to be rr. Next, a negative DC voltage (applied power density of about 2.0
W / cm ² ) was applied and DC sputtering of a titanium target was performed to form a titanium nitride film 11 having a thickness of 14 nm (geometric film thickness, the following film thickness is also the same) (step 1).

Next, after the gas introduction was stopped and the vacuum chamber was evacuated to a high vacuum, a mixed gas of argon and oxygen (50% by volume of oxygen) was introduced as a discharge gas at a pressure of 2 × 10 ⁻³ To.
The conductance was adjusted to be rr. Then, the voltage of the waveform shown in FIG. 3 is applied to the silicon cathode, and the silicon target is intermittently DC sputtered to
A 00 nm silica film 13 (refractive index 1.46) was formed (step 2).

The spectral transmittance of the obtained light-absorbing antireflection glass was measured. In addition, the spectral reflectance of this sample is
A black lacquer was applied to the back surface of the glass substrate, and the measurement was performed from the film surface side while the back surface reflection was erased. The obtained spectral transmittance curve 42 and spectral reflectance curve 41 are shown in FIG.

Further, when the glass substrate with the titanium nitride film was taken out after the step 1 and the titanium nitride film was analyzed by ESCA, the atomic ratio was Ti: N: O = 1: 0.86: 0.
It was 16.

Example 2 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr.
A two-layer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows. A 14 nm titanium nitride film was formed in the same manner as in Example 1 except that the discharge gas in Step 1 of Example 1 was changed to nitrogen gas (100% nitrogen). Next, Example 1
A 100 nm silica film was formed in the same manner as in Step 2 of.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. The atomic ratio was Ti: N: O = 1: 0.92: 0.20. .

Example 3 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ^-5 Torr.
A two-layer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows. A 12 nm titanium nitride film was formed in the same manner as in Example 1, except that the discharge gas in Step 1 of Example 1 was replaced with a mixed gas of 10 vol% nitrogen and argon. Then, in the same manner as in Step 2 of Example 1, a silica film having a thickness of 85 nm was formed.

The spectral reflectance curve 61 of the obtained light-absorbing antireflection glass was measured in the same manner as in Example 1. FIG. 6 shows the results.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. As a result, the atomic ratio was Ti: N: O = 1: 0.95: 0.08. Incidentally, for the obtained light-absorbing antireflection glass,
FIG. 14 shows the curve of the spectral reflectance after the heat treatment at 450 ° C. for 30 minutes is performed three times.

Example 4 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr.
A two-layer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows. In the same manner as in Example 3, a 7 nm titanium nitride film and an 85 nm silica film were sequentially formed.

With respect to the obtained light-absorbing antireflection glass, the curve of spectral reflectance was measured in the same manner as in Example 1.
The results are shown in FIG. After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. As a result, the atomic ratio was Ti: N: O = 1: 0.95: 0.09.
Met.

Example 5 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ^-5 Torr.
A two-layer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows. A 20 nm thick titanium nitride film was formed in the same manner as in Step 1 of Example 1. Then, a 100 nm silica film was formed in the same manner as in Step 2 of Example 1.

With respect to the obtained light-absorbing antireflection glass, the curve of spectral reflectance was measured in the same manner as in Example 1.
The results are shown in FIG. After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. The atomic ratio was Ti: N: O = 1: 0.84: 0.17.
Met.

Example 6 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ^-5 Torr.
A multilayer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows. A 14 nm titanium nitride film was formed in the same manner as in Step 1 of Example 1.

Next, the discharge gas was switched to 100% argon, the pressure was adjusted to 2 × 10 ⁻³ Torr, a negative DC voltage was applied to the silicon cathode, and the silicon target was DC-sputtered to form an oxide barrier film. As a result, a 2 nm silicon film was formed. Then, a 100 nm silica film was formed in the same manner as in Step 2 of Example 1.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. As a result, the atomic ratio was Ti: N: O = 1: 0.88: 0.14.

Example 7 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr. A multilayer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows.

First, in the same manner as in Example 3, a 12 nm titanium nitride film was formed. Next, the discharge gas is 30% by volume of nitrogen.
Switch to a mixed gas of Argon and Nitrogen, and set the pressure to 2 x 1
After adjusting to 0 ^-3 Torr, a negative DC voltage was applied to the silicon cathode, and a 5 nm light-absorbing silicon nitride film was formed as an oxidation barrier film by DC sputtering of a silicon target. Then, in the same manner as in Example 3, a 85 nm silica film was formed thereon.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride was analyzed by ESCA. As a result, the atomic ratio was Ti: N: O = 1: 0.97: 0.06.
In addition, about the obtained light-absorbing antireflection glass, 45
FIG. 15 shows the curve of the spectral reflectance after the heat treatment at 0 ° C. for 30 minutes is performed three times.

Example 8 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr.
Oxygen gas was introduced as the discharge gas and the pressure was 2 × 10 ⁻³ T
After adjusting to orr, a negative DC voltage was applied to the titanium cathode, and DC sputtering of the titanium target was performed to achieve 3 on the soda-lime glass substrate installed in the vacuum chamber.
An underlayer of titanium oxide film having a thickness of 10 nm was formed. Then, in the same manner as in Example 3, a 12 nm titanium nitride film and an 85 nm silica film were formed on the titanium oxide film.

With respect to the obtained light absorbing antireflection glass, the curve 71 of the spectral reflectance was measured in the same manner as in Example 1. FIG. 7 shows the results. After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1, and the titanium nitride film was analyzed by ESCA. The atomic ratio was Ti: N: O = 1: 0.93: 0.0.
It was 7.

Example 9 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ^-5 Torr.
PET substrate installed in vacuum chamber (with hard coat, 1
A two-layer film was formed on the above (50 μm thick) as follows. A 12 nm titanium nitride film and an 85 nm silica film were formed in the same manner as in Example 3.

With respect to the obtained PET with a light-absorbing antireflection film, a curve 81 of the spectral reflectance was measured in the same manner as in Example 1. The results are shown in Fig. 8. After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. The atomic ratio was Ti: N: O = 1: 0.91:
It was 0.11.

Example 10 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr. A three-layer film was formed on the soda-lime glass substrate 20 installed in the vacuum chamber as follows, to obtain a light-absorbing antireflection body as shown in FIG.

Using the same gas and pressure as in Step 1 of Example 1, a negative DC voltage was applied to the titanium cathode, and a titanium nitride film 21 of 30 nm was formed by DC sputtering of a titanium target.

Next, after the gas introduction was stopped and the vacuum chamber was evacuated to a high vacuum, a negative DC voltage was applied to the titanium cathode using the same gas and pressure as in step 1 of Example 1 to obtain a titanium target. 18 nm of titanium oxide film 22 (refractive index of about 2.2) was formed by DC sputtering.

Next, with the introduced gas as it is, the voltage of the waveform shown in FIG. 3 is applied to the silicon cathode, and the silicon target is subjected to intermittent DC sputtering to obtain 63 nm.
The silica film 23 was formed.

After the titanium nitride film was formed, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. The atomic ratio was Ti: N: O = 1: 0.87: 0.14. .

Example 11 Instead of the titanium oxide film in Example 10, an ITO (tin-doped indium oxide) target was used to form an ITO film (refractive index about 2.0), and a titanium nitride film and silica were used. Example 1 except that the film thickness was changed
In the same manner as in 0, a light absorbing antireflection body with a three-layer film was obtained.

That is, as in Example 10, first, 2
Same except that a 3 nm titanium nitride film was formed, an ITO cathode was used instead of the titanium cathode of Example 10, and a mixed gas of argon and oxygen (oxygen was 1% by volume) was used as a discharge gas. And perform DC sputtering,
A 22 nm ITO film was formed, and finally a 59 nm silica film was formed.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. The atomic ratio was Ti: N: O = 1: 0.86: 0.18. .

Example 12 Using the same apparatus and target as in Example 10, the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr. Oxygen gas was introduced as the discharge gas, and the pressure was 2 × 10
After adjusting to ^-3 Torr, a negative DC voltage was applied to the titanium cathode, and a 3 nm titanium oxide film was formed as an underlayer on the soda lime glass substrate installed in the vacuum chamber by DC sputtering of the titanium target. .

Next, Example 10 was formed on the titanium oxide film having a thickness of 3 nm.
In the same manner as above, a 30 nm titanium nitride film, an 18 nm titanium oxide film and a 63 nm silica film were sequentially formed.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. As a result, the atomic ratio was Ti: N: O = 1: 0.85: 0.17.

Example 13 Using the same apparatus and target as in Example 10, the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr. A three-layer film was formed on a soda lime glass substrate installed in a vacuum chamber as follows.

First, in the same manner as in Example 10, a 30 nm thick titanium nitride film was formed. Next, the discharge gas was replaced with argon 10.
After switching to 0% and adjusting the pressure to 2 × 10 ⁻³ Torr, a negative DC voltage was applied to the silicon cathode, and a 3 nm silicon film was formed as an oxidation barrier film by DC sputtering of the silicon target. Next, Example 1
In the same manner as for 0, a 18 nm titanium oxide film and 6
A 3 nm silica film was formed.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride was analyzed by ESCA. The atomic ratio was Ti: N: O = 1: 0.88: 0.16.

Example 14 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ^-5 Torr. On the soda lime glass substrate installed in the vacuum tank,
In the same manner as in Example 3, a two-layer film including a titanium nitride film having a thickness of 9 nm and a silica film having a thickness of 85 nm was formed in this order. After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1, and the titanium nitride film was analyzed by ESCA. The atomic ratio was Ti: N: O.
= 1: 0.94: 0.11. The spectral reflectance of the obtained sample was measured in the same manner as in Example 1. Figure 1 shows the results
It is shown in FIG.

Example 15 Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ^-5 Torr. A two-layer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows.

First, a 12 nm titanium nitride film was formed in a mixed gas atmosphere of argon and nitrogen containing 10% by volume of nitrogen in the same manner as in Example 3. At this time, in the case of Example 3, the power to be supplied to the titanium target was changed. 1/4, that is, the input power density was about 0.5 W / cm ² . Then, a 102 nm silica film was formed in the same manner as in Example 3.

After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was analyzed by ESCA. As a result, the atomic ratio was Ti: N: O = 1: 0.70: 0.65.

The spectral reflectance of the obtained sample was measured in the same manner as in Example 1. FIG. 13 shows the results.

Example 16 (Comparative Example) The same as Example 1 except that an ITO film was formed by using an ITO target instead of the titanium nitride film in Example 1 and the thickness of the silica film was changed. Thus, an antireflection body with a two-layer film was obtained.

That is, DC sputtering was performed in the same manner except that an ITO cathode was used in place of the titanium cathode of Example 1 and a mixed gas of argon and oxygen (oxygen was 1% by volume) was used as the discharge gas, and the thickness was 30 nm. ITO
Then, a 110 nm silica film was formed in the same manner as in Example 1.

For the obtained sample, in the same manner as in Example 1, the curve 52 of the spectral transmittance and the curve 5 of the spectral reflectance were obtained.
1 was measured. Results are shown in FIG.

Example 17 (Comparative Example) Using the same apparatus and target as in Example 1, the vacuum chamber was evacuated to 1 × 10 ^-5 Torr. A two-layer film was formed on a soda lime glass substrate placed in a vacuum chamber as follows. A 30 nm titanium nitride film and a 100 nm silica film were formed in the same manner as in Example 1.

With respect to the obtained sample, in the same manner as in Example 1, the curve 92 of the spectral transmittance and the curve 9 of the spectral reflectance were obtained.
1 was measured. FIG. 9 shows the results. After forming the titanium nitride film, the substrate was taken out in the same manner as in Example 1 and the titanium nitride film was removed by E
When analyzed by SCA, the atomic ratio was Ti: N: O = 1: 1.
It was 0.87: 0.15.

The antireflection glass obtained in each of Examples 1 to 17 was cut into a 3 cm square, and electrodes were formed on the four corners of the film surface with glass solder. Surface resistance measured by the van der Pauw method, luminous reflectance and luminous transmittance obtained from spectral curves, and light absorption rate for incident light from the silica film side (hereinafter, simply referred to as light absorption rate) And are summarized in Table 1.

In addition, the same light-absorbing antireflection glass can be used with 45
A wavelength range in which the surface resistance value measured in the same manner after heat treatment at 0 ° C. for 30 minutes for three times and the luminous reflectance, luminous transmittance, light absorption rate and reflectance are 0.6% or less. Is shown in Table 1. In Table 1, "before" and "after" mean before and after heat treatment, respectively.

As can be seen from Table 1 and FIGS.
According to the present invention, a light-absorbing antireflection glass having excellent heat resistance can be realized with a simple film structure.

Comparing the spectral reflectance curves of Example 16 (comparative example) composed only of the transparent film and Example 1, the spectral reflectance curve of Example 1 has a wider low reflection region and exhibits excellent antireflection characteristics. .

As can be seen from the spectral transmittance curve and the luminous transmittance in Table 1, the light absorption film used in the present invention can reduce the transmittance as compared with the transparent antireflection film. Therefore, the present invention can be applied to a panel glass, a face plate, a panel glass installed in front of a display screen of a CRT,
When applied to a filter glass or the like, the effect of improving the contrast of the display screen becomes more remarkable than in the case of a transparent antireflection film.

As can be seen from these examples,
According to the present invention, by selecting the film thickness of the light absorbing film within a preferable range, the light absorption rate for incident light from the silica film side of the light absorbing antireflection film of the present invention is in the range of 10 to 35%. Can be adjusted with. As can be seen from the spectral reflectance diagrams of the examples, if the film thickness of the light absorption film is increased, the low reflection wavelength region is narrowed, and therefore the film thickness may be selected according to the purpose.

Examples 1 to 5, 14 and FIGS. 4, 6 and 1
0 and FIG. 11 and Example 17 (comparative example) and FIG. 9, it can be seen that the antireflection performance is extremely excellent by appropriately selecting the film formation conditions and film thickness of titanium nitride and the film thickness of the silica film. It can be done. However, when the titanium nitride is thinned to improve the antireflection performance, the heat resistance is slightly lowered and the characteristic change after the heat treatment is slightly increased.

As can be seen from Example 5, when the film thickness of titanium nitride is increased, the change in characteristics due to heat treatment is more relaxed than when it is thin. However, in this case, although the luminous reflectance before heat treatment is as low as 0.12%, the reflectance is remarkably increased in the wavelength region at both ends of visible light, and the reflected color is pale bluish purple.

As can be seen from Examples 6 and 7, heat resistance can be remarkably improved by forming the oxidation barrier layer on the titanium nitride film even when the titanium nitride film is thin.

As can be seen from Example 8 and FIG. 7, the reflection color tone can be made closer to colorless by inserting the reflection color adjustment layer in the film structure.

As can be seen from Example 9 and FIG. 8, even when a plastic is used as the substrate, the present invention makes it possible to obtain a light-absorptive antireflection material exhibiting excellent low reflection characteristics.

Before and after the heat treatment of the samples of Examples 1 to 15 described above, a scratch resistance test (500
As a result of carrying out g load, 20 reciprocations, no scratches that would pose a problem in practical use were found in any of the cases. In particular, Examples 1-
No scratches were observed when the samples of Example 9 and Examples 14 to 15 were heat treated before and after heat treatment.

[0162]

[Table 1]

[0163]

The multilayer film used in the light-absorbing antireflection body of the present invention has appropriate light absorption and antireflection performance,
It can be realized with a simple film structure and without increasing the total film thickness.

Further, it is possible to provide a light-absorptive antireflection member having a resistance value of 1 kΩ / □ or less and having an electromagnetic wave shielding property, because the contrast can be increased by lowering the transmittance.

Further, since the present invention substantially has a two-layer or three-layer structure, compared with the conventional antireflection film having a multilayer structure,
It has a small number of film interfaces and is excellent in mechanical strength such as scratch resistance and heat resistance. This is particularly remarkable in the case of the two-layer film structure of the first invention. Further, in the present invention, when DC sputtering is used as a film forming method, there are advantages such as process stability and easy enlargement of the area. Can be produced.

The light-absorptive antireflection material according to the present invention is excellent in heat resistance and can sufficiently withstand the heat treatment required for the panel glass of a cathode ray tube. Expected to be applied to applications.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of the present invention.

FIG. 2 is a schematic cross-sectional view of another example of the present invention.

FIG. 3 is a graph showing a time variation of a voltage applied to a silicon target used in Examples and Comparative Examples.

FIG. 4 is a graph showing the spectral reflectance and spectral transmittance of Example 1.

FIG. 5 is a graph showing the spectral reflectance and the spectral transmittance of Example 16.

FIG. 6 is a graph showing the spectral reflectance of Example 3.

7 is a graph showing the spectral reflectance of Example 8. FIG.

FIG. 8 is a graph showing the spectral reflectance of Example 9.

9 is a graph showing the spectral reflectance and the spectral transmittance of Example 17. FIG.

FIG. 10 is a graph showing the spectral reflectance of Example 4.

FIG. 11 is a graph showing the spectral reflectance of Example 5.

FIG. 12 is a graph showing the spectral reflectance of Example 14.

FIG. 13 is a graph showing the spectral reflectance of Example 15.

FIG. 14 is a graph showing the spectral reflectance after heat treatment in Example 3.

FIG. 15 is a graph showing the spectral reflectance after heat treatment in Example 7.

FIG. 16 is a graph showing the dispersion relation of the optical constants of an ideal absorption film, which is obtained by calculation.

FIG. 17 is a diagram showing an example of using the light-absorbing antireflection body of the present invention.

[Explanation of symbols]

V _N : Negative voltage applied to the silicon target in Examples and Comparative Examples

Claims (24)

[Claims] 1. A light-absorptive antireflection material comprising a light-absorbing film and a silica film formed in this order on a substrate in order to reduce reflection of incident light from the silica film side. A light-absorptive antireflection body, wherein the geometrical film thickness of the film is 5 to 25 nm, and the geometrical film thickness of the silica film is 70 to 110 nm. 2. The geometric thickness of the light absorbing film is 7 to 20 n.
The light-absorbing antireflection body according to claim 1, which is m. 3. The geometrical thickness of the light absorbing film is 10 to 20.
The light-absorptive antireflection member according to claim 1 or 2, having a thickness of nm. 4. The geometric thickness of the light absorbing film is 7 to 15 n.
The light-absorbing antireflection body according to claim 1 or 2, which is m. 5. The geometric thickness of the silica film is 80 to 10.
It is 0 nm, The light absorptive antireflection body of any one of Claims 1-4. 6. The light absorptivity according to claim 1, wherein the light absorptivity of the light absorptive antireflection material is 10 to 35% with respect to the incident light from the silica film side. Anti-reflective body. 7. The light absorbing film comprises titanium, zirconium,
And at least one selected from the group consisting of hafnium
7. A film containing a nitride of a seed metal as a main component.
The light-absorbing antireflection body as described in any one of 1. 8. The light-absorptive antireflection member according to claim 1, wherein the light-absorbing film is a film containing titanium nitride as a main component. 9. The film containing titanium nitride as a main component,
Nitrogen and a rare gas are contained as main components, and the ratio of the nitrogen is 3
The light-absorptive antireflection member according to claim 8, which is a film formed by sputtering in a sputtering gas atmosphere of ˜50% by volume. 10. The light absorbing antireflection member according to claim 8, wherein the film containing titanium nitride as a main component is a film containing oxygen having an atomic ratio to titanium of 0.5 or less. 11. Between the light absorption film and the silica film,
The light-absorptive antireflection body according to any one of claims 1 to 10, wherein a layer containing a metal or a metal nitride as a main component having a geometric film thickness of 1 to 20 nm is formed. 12. The light absorbing antireflection member according to claim 11, wherein the layer containing a metal or a metal nitride as a main component is a layer containing silicon or a silicon nitride as a main component. 13. The light-absorptive antireflection member according to claim 1, wherein the substrate is a glass substrate, a plastic substrate or a plastic film which constitutes a front surface of a display surface for a display. 14. The reflectance of the light-absorbing antireflection material is 5
The light-absorptive antireflection member according to any one of claims 1 to 13, which does not exceed 0.6% in a wavelength region of 00 to 650 nm. 15. A light-absorbing film formed by forming a light-absorbing film, a high-refractive-index transparent film, and a silica film on a substrate in this order to reduce reflection of incident light from the silica film side. In the antireflection body, the geometric thickness of the light absorbing film is 15 to 30.
and the geometric thickness of the high refractive index transparent film is 10 to 4
0 nm, and the silica film has a geometrical thickness of 50 to 50 nm.
A light-absorptive antireflection material having a thickness of 90 nm. 16. The light absorptivity of the light absorptive antireflection material is
The light-absorptive antireflection member according to claim 15, wherein the content is 30 to 60% with respect to the incident light from the silica film side. 17. The light absorption film is a film containing a nitride of at least one metal selected from the group consisting of titanium, zirconium, and hafnium as a main component.
The light-absorbing antireflection body as described in 5 or 16. 18. The light absorbing antireflection body according to claim 15, wherein the light absorbing film is a film containing titanium nitride as a main component. 19. A sputtering gas atmosphere, wherein the film containing titanium nitride as a main component contains nitrogen and a rare gas as main components, and the ratio of the nitrogen is 3 to 50% by volume.
The light absorbing antireflection body according to claim 18, which is a film formed by sputtering. 20. The light absorbing antireflection member according to claim 18, wherein the film containing titanium nitride as a main component is a film containing oxygen having an atomic ratio to titanium of 0.5 or less. 21. Between the light absorbing film and the high refractive index transparent film, or between the high refractive index transparent film and the silica film,
The light-absorptive antireflection body according to any one of claims 15 to 20, wherein a layer containing a metal or a metal nitride as a main component having a geometric film thickness of 1 to 20 nm is formed. 22. The light absorbing antireflection member according to claim 21, wherein the layer containing a metal or a metal nitride as a main component is a layer containing silicon or a silicon nitride as a main component. 23. The light-absorptive antireflection member according to claim 15, wherein the substrate is a glass substrate, a plastic substrate or a plastic film which constitutes a front surface of a display surface for a display. 24. The reflectance of the light-absorbing antireflection member is 5
The light-absorptive antireflection member according to any one of claims 15 to 23, which does not exceed 0.6% in a wavelength region of 00 to 650 nm.