JP3353944B2 - Antireflection film for optical component and optical component formed with this antireflection film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film applied to a surface of an optical component and an optical component having the antireflection film formed thereon.

[0002]

2. Description of the Related Art In recent years, resin parts have been frequently used as materials for optical parts such as lenses, mirrors and prisms. Compared to glass optical parts, resin optical parts can be made more complex, lower in cost and lighter in weight, and are easier to process than glass parts when forming optical parts with complicated shapes. It also has the advantage.

[0003] By the way, parts made of these resins have to be subjected to some surface treatment because they are inferior in abrasion resistance and scratch resistance as compared with glass and metal. In particular, in order to use resin as an optical component, it is necessary to form an optical thin film as in the case of optical glass. Also, CCD
In recent years, there has been an increasing demand for providing an antireflection film on an optical device such as described above, or on an optical component in which glass or the like is bonded thereto, and in this case also, it is necessary to form an antireflection film on an arbitrary surface.

In recent years, as an optical multilayer film of a resin optical component, many anti-reflection films mainly related to an anti-reflection film have been proposed. For example, an anti-reflection film as disclosed in JP-A-62-191801 is known. Are known. This is because SiO ₂ , ZrO ₂ + TiO ₂ are sequentially arranged from the air side to the resin substrate side.
₂ , ZrO ₂ , SiO or SiO ₂ .

[0005]

In order to obtain a sufficient anti-reflection effect over a wide wavelength range, it is necessary to alternately combine a low-refractive index material and a high-refractive index material. As the substance, TiO ₂ or ZrO ₂ found in the above-mentioned conventional technology is often used. However, TiO ₂ , ZrO _2, etc. have a high melting point, and in the same setting method of an apparatus as when an antireflection film is formed on a normal glass substrate, the plastic substrate is heated by the influence of radiant heat from an evaporation source, and the substrate is heated. There is a possibility that the surface may be damaged and the adhesion of the film may be degraded, or the surface accuracy which is the most important for the optical component may be degraded. This is particularly noticeable when a heat-sensitive acrylic resin (PMMA) is used for the substrate.

[0006] As a countermeasure, there can be considered a method of increasing the distance from the evaporation source to the substrate or providing a shielding plate between the evaporation source and the substrate to reduce the influence of radiant heat from the evaporation source. However, each of the above methods requires a significant modification of the film forming apparatus, and has a disadvantage that a conventional apparatus for forming an antireflection film on a glass substrate cannot be used as it is. In addition, the above method inevitably requires a long deposition time, which is not preferable in terms of productivity.

[0007] These points are the same when the substrate is made of an optical component other than synthetic resin, such as an optical component such as a CCD, or a component obtained by bonding the optical component to glass. That is, CCD
In such a semiconductor device, there is a possibility that the device itself may be destroyed by high heat. Further, in the case of a bonded product, there is a possibility that the strength of the bonded portion may be deteriorated or peeled off.

Therefore, if a material having low radiation heat from the evaporation source can be used, the above-mentioned problem can be solved. Such materials include MoO ₃ and WO ₃ . MoO ₃ and WO ₃ have heretofore been little noticed as materials for optical thin films. However, if they are completely oxidized, they do not absorb light and have a refractive index of about 1.85 to 2.1. (Depending on the film forming conditions). Therefore, it is possible to form a broadband anti-reflection film using MoO ₃ and WO ₃ as high refractive index substances. However, when the antireflection film using MoO ₃ or WO ₃ is left under high humidity for a long time, there is a problem that the adhesion is slightly deteriorated.

The present invention has been made in view of the above-mentioned problems. Even when an optical device such as a resin substrate or a CCD or a device obtained by bonding the optical device to glass or the like is used as a substrate for an optical component, the substrate has high adhesion, and An anti-reflection film that can be easily formed using a conventional apparatus without deteriorating the area degree and without damaging the substrate by heat, has good productivity, and has excellent durability, particularly excellent moisture resistance. It is an object to provide an optical component having the antireflection film formed thereon.

[0010]

The antireflection film according to the first aspect of the present invention comprises a Si film formed on a substrate of an optical component.
Oxide layer and Mo formed on the Si oxide layer.
It has a layer containing at least one of O ₃ and WO ₃ , and an outermost layer having a water-repellent effect formed on the uppermost surface of the layer. The optical component according to the second invention is an optical component having an antireflection film formed on a substrate, wherein the optical component is formed on the Si oxide layer formed on the substrate and the Si oxide layer. It has a layer containing at least one of MoO ₃ and WO ₃ and an outermost layer having a water-repellent effect formed on the uppermost surface of the layer.

Here, the substrate means a synthetic resin such as acrylic, polycarbonate, amorphous polyolefin, CR-39 and energy-curable resin, an optical device or an optical member such as a CCD which is required not to be exposed to high temperatures, or And those constituting optical components, such as those obtained by bonding glass to glass. Further, a PVD method such as a vacuum evaporation method or a sputtering method can be used for forming the film.

As described above, MoO ₃ and WO ₃ can suppress the radiation heat from the evaporation source to a low level, and do not damage the optical component substrate due to the heat. And, because a layer having a water repellent effect is provided on the outermost layer,
Moisture is hardly supplied to the inside of the anti-reflection film, and the moisture resistance, which is a weak point when MoO ₃ or Wo ₃ is used as one layer constituting the anti-reflection film, can be greatly improved. The material of the layer having a water-repellent effect and the method for forming the same are not particularly limited as long as they have a sufficient water-repellent effect and durability. Further, the thickness of the layer may be thick enough to perform the function of the optical film, or may be such that the optical effect is not exerted.

[0013]

Embodiment 1 FIG. 1 is a schematic structural view of an apparatus used in this embodiment. In the present example, the antireflection film was configured as shown in Table 1 below. That is, the refractive index n = 1.49
Five layers of SiO ₂ and WO ₃ are alternately laminated on the surface of a plastic substrate made of acrylic resin (PMMA), and a water-repellent layer is provided thereon with a thickness that does not affect optically. is there.

[0014]

[Table 1]

The antireflection film having the above structure was formed by using the vacuum evaporation apparatus shown in FIG. Reference numeral 10 denotes a vacuum chamber, and a resistance heating evaporation source 11 and an electron gun evaporation source 12 are provided at lower positions in the vacuum chamber 10, respectively. 13
Reference numeral denotes a resistance heating melting boat attached to the resistance heating evaporation source 11, and reference numeral 14 denotes a hearth of an electron gun evaporation source. At an upper position in the vacuum chamber 10, a rotating dome 15 that is rotatable about an axis on which the substrate 1 can be mounted is provided.

Reference numeral 16 denotes a vacuum exhaust pipe connected to a vacuum pump (not shown). The distance from the evaporation source to the substrate is about 520 mm. As can be seen from the above description, the present apparatus has no difference from the conventional apparatus for forming an antireflection film on a glass substrate. A method for forming an antireflection film having the structure shown in Table 1 using the apparatus shown in FIG. 1 will be described below.

The acrylic substrate 1 is fixed to the rotating dome 15, and the inside of the vacuum chamber 10 is evacuated to 3 × 10 ^-6 Torr using an oil diffusion pump (not shown). The SiO ₂ layer was formed by putting a granulated SiO ₂ into a hearth 14 and heating it with an electron gun. Also,
The WO ₃ layer is obtained by adding a small amount (5 wt%) of Al ₂ O ₃ to WO ₃ and forming it into a pellet and heating it with an electron gun to evaporate it, while introducing oxygen gas to 1 × 10 ⁻⁵ Torr. Formed.

In this case, since Al ₂ O ₃ has a significantly lower vapor pressure than WO ₃ , there is no Al ₂ O ₃ in the film. However, by adding Al ₂ O ₃ , the effects of preventing cracking of the pellets, reducing electrification, and preventing splash can be obtained. The outermost water-repellent treatment layer is obtained by evaporating only the impregnated oil component by heating a porous material impregnated with a fluorine-based silicone oil in a resistance heating melting boat 13. The film thickness is about 3 nm in terms of the optical film thickness nd and does not affect the optical characteristics at all. However, the wetting angle of water is 97 ° and has a sufficient water repellent effect.

The reflectance of the thus formed antireflection film was 1% or less in the entire visible region, and had sufficient characteristics. Further, even in an adhesion test using a cellophane tape, the film was not peeled off, and it was confirmed that the film had sufficient adhesion. Further, the film was left to stand in an environment of a temperature of 45 ° C. and a humidity of 95% for 300 hours, and the adhesion and optical characteristics of the film were examined. As a result, there was no change compared to before the film was left, and it was found that the film had sufficient moisture resistance. confirmed.

As a comparative example, a sample having the same film configuration as in the present embodiment was formed except that the outermost water-repellent layer was not provided, and this was left in an environment at a temperature of 45 ° C. and a humidity of 95% for 300 hours. When the test was performed, it was peeled off.

[0021]

[Embodiment 2] In this embodiment, an antireflection film was formed with a structure as shown in Table 2 below. That is, the refractive index n = 1.49
S on the surface of a plastic substrate made of acrylic resin
Five layers of iO ₂ and MoO ₃ are alternately laminated, and a water-repellent layer is further provided thereon with a thickness having no optical influence.

[0022]

[Table 2]

Using the apparatus shown in FIG. 1, an SiO ₂ layer and a water-repellent layer were formed in the same manner as in Example 1. The MoO ₃ layer was formed by putting granular MoO ₃ into the boat 13 and introducing oxygen gas to 1 × 10 ⁻⁴ Torr. The antireflection film of this example also had sufficient optical characteristics and moisture resistance as in Example 1.

[0024]

Embodiment 3 In this embodiment, a film configuration as shown in Table 3 below was adopted. Except that polycarbonate (PC) was used as the substrate and the outermost water-repellent layer was the same as in the first embodiment.

[0025]

[Table 3]

The outermost water-repellent layer was formed by the following method. After forming the first to fifth layers in the same manner as in Example 1, the substrate is taken out of the chamber, and a transparent fluororesin diluted to 0.06% by weight is optically coated to a thickness of 10 nm using a spinner. Form. further,
Thereafter, by heating the substrate at 80 ° C. for 1 hour, the monomers present individually are combined to form a strong amorphous polymer layer. This layer has a wetting angle with water of 92 ° and has a sufficient water repellent effect.

The reflectivity of the antireflection film thus formed was 1% or less in the entire visible region, and had sufficient characteristics. Further, even in an adhesion test using a cellophane tape, the film was not peeled off, and it was confirmed that the film had sufficient adhesion. Further, the film was left to stand in an environment of a temperature of 45 ° C. and a humidity of 95% for 300 hours, and then the adhesion and optical characteristics of the film were examined. confirmed.

[0028]

Embodiment 4 In this embodiment, a film configuration as shown in Table 4 below was adopted. That is, four layers of SiO ₂ and WO ₃ are alternately laminated on a plastic substrate made of an amorphous polyolefin resin having a refractive index of n = 1.53, and a water-repellent layer is further formed thereon to have an optical film thickness of 130 nm. It is provided as follows.

[0029]

[Table 4]

Using the apparatus shown in FIG. 1, an SiO ₂ layer was formed in the same manner as in Example 1. In the WO ₃ layer, granular WO ₃ was put into the boat 13 and oxygen gas was supplied at 5 × 10 3.
^-5 Torr.

The outermost water-repellent layer was formed by the following method. After forming the first to fourth layers, the substrate is taken out of the chamber, and a transparent fluororesin diluted to 0.1% by weight is coated with an optical film having a thickness of 130 nm by dipping.
nm. Thereafter, by heating the substrate at 90 ° C. for 1 hour, the monomers present individually bind to each other to form a strong amorphous polymer layer. This layer has a wetting angle of 96 ° with water and has a sufficient water repellent effect.

The reflectance of the thus formed antireflection film was 1% or less in the entire visible region, and had sufficient characteristics. Further, even in an adhesion test using a cellophane tape, the film was not peeled off, and it was confirmed that the film had sufficient adhesion. Further, the film was left to stand in an environment of a temperature of 45 ° C. and a humidity of 95% for 300 hours, and the adhesion and optical characteristics of the film were examined. As a result, there was no change compared to before the film was left, and it was found that the film had sufficient moisture resistance. confirmed.

[0033]

Embodiment 5 FIG. 2 is a schematic structural view of an apparatus used in this embodiment. In this example, the film configuration was as shown in Table 5 below. That is, the refractive index n =
1.52 UV curable resin is integrally formed on a glass substrate, and a total of six layers of SiO, SiO ₂ and WO ₃ are laminated, and a water-repellent treatment layer is further formed thereon so as to have no optical influence. It is provided with a film thickness of.

[0034]

[Table 5]

The SiO ₂ layer using the apparatus of Figure 1 and WO
_{The three} layers were formed in the same manner as in Example 1. The outermost water-repellent layer was formed by the following method. After forming the first to sixth layers, the substrate is removed from the chamber of the apparatus of FIG. 1 and transferred to the chamber of the apparatus of FIG. 20
Is a vacuum chamber, in which electrodes 21 and 22 for generating plasma and a gas inlet 23 are disposed. Reference numeral 24 denotes a vacuum exhaust pipe connected to a vacuum pump (not shown).

The substrate 25 is set on the substrate holder 26, and the inside of the vacuum chamber 20 is evacuated to 1 × 10 ⁻³ Torr or less. Subsequently, gaseous fluorine-based silicone is introduced from the gas inlet 23 and the electrodes 21 and
A high frequency is applied between the two to generate plasma. By this operation, the monomers present individually bind to each other, and a strong amorphous polymer layer having a thickness of about 2 to 3 nm is formed on the outermost layer. This layer has a wetting angle with water of 90 ° and has a sufficient water repellent effect.

The reflectance of the thus formed antireflection film was 1% or less over the entire visible region, and had sufficient characteristics. Further, even in an adhesion test using a cellophane tape, the film was not peeled off, and it was confirmed that the film had sufficient adhesion. Further, the film was left to stand in an environment of a temperature of 45 ° C. and a humidity of 95% for 300 hours, and the adhesion and optical characteristics of the film were examined. As a result, there was no change compared to before the film was left, and it was found that the film had sufficient moisture resistance. confirmed.

[0038]

[Embodiment 6] This embodiment shows an example in which a film having the same film configuration as in Table 1 is formed by a different method. As a film forming apparatus, a commercially available magnetron sputtering apparatus was used as it was. After evacuating the inside of the vacuum chamber to 5 × 10 ⁻⁵ Torr using a turbo molecular pump, 5
A mixed gas of argon and oxygen was introduced until the pressure reached × 10 ⁻³ Torr, and WO ₃ and SiO ₂ were each formed by a magnetron sputtering method to form five antireflection films.

The water-repellent layer was formed in the same manner as in Example 1. The antireflection film of this embodiment is also the same as that of the first embodiment.
It had sufficient optical properties and moisture resistance in the same manner as.

[0040]

[Embodiment 7] In this embodiment, an antireflection film was formed on the glass of an article (optical component) in which glass was bonded to a CCD as a substrate, using the same film configuration and technique as in the first embodiment. The antireflection film of this example also had sufficient optical characteristics and moisture resistance as in Example 1. No heat was applied to the CCD or the bonding surface, and there was no damage to the substrate.

[0041]

As described above, according to the antireflection film for an optical component according to the present invention, at least one of MoO _{3 and} WO ₃ formed on a substrate by a PVD method (physical vapor deposition method). By including at least one layer made of a material containing, and by providing a layer having a water-repellent effect on the outermost layer, radiant heat from the evaporation source can be suppressed without any modification to a conventional film forming apparatus. Can be
Deterioration of film adhesion and surface accuracy due to thermal damage to the substrate, deterioration of bonding strength of bonded products, deterioration of device performance, etc. do not occur, and productivity is good. Furthermore, it becomes difficult for moisture to be supplied inside the antireflection film,
MoO ₃ or WO ₃ can greatly improve moisture resistance, which is a weak point when using Mo ₃ . Further, according to the optical component having the antireflection film according to the present invention, the adhesion between the substrate and the film is deteriorated and the surface accuracy is deteriorated. Performance degradation does not occur, and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment.

FIG. 2 is a schematic configuration diagram showing a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 10 Vacuum chamber 11 Resistance heating evaporation source 12 Electron gun evaporation source 13 Melting boat for resistance heating 14 Hearth 15 Rotating dome 16 Vacuum exhaust pipe

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-313157 (JP, A) JP-A-6-27456 (JP, A) JP-A-6-102499 (JP, A) JP-A-6-102499 102500 (JP, A) JP-A-6-214101 (JP, A) JP-A-54-33745 (JP, A) JP-A-63-132201 (JP, A) JP-A-63-132203 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 1/11

Claims (2)

(57) [Claims] 1. An Si oxide layer formed on a substrate of an optical component, and MoO ₃ and WO formed on the Si oxide layer
_3. An anti-reflection film for an optical component, comprising: a layer containing at least one of the above-mentioned items 3; 2. An optical component having an antireflection film formed on a substrate, comprising: an Si oxide layer formed on the substrate; and MoO ₃ and WO formed on the Si oxide layer.
_3. An optical component, comprising: a layer containing at least one of the following; and an outermost layer having a water-repellent effect formed on the uppermost surface of the layer.