JPH0685001B2 - Optical article having multilayer antireflection film - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an optical article having a multilayer antireflection film having excellent adhesion strength. More specifically, the present invention relates to an optical article having a multilayer antireflection film useful as a lens for spectacles, an optical lens such as a lens for a camera, an optical filter attached to a display such as a word processor or a cathode ray tube of a television, a window glass of an automobile or the like.

[Prior Art] A plastic molded body represented by a plastic lens has extremely excellent impact resistance and transparency, is lightweight, and is easily dyed, and therefore, in recent years, the demand has greatly increased. However, plastic optical products have a lower surface hardness than inorganic glass and are liable to be scratched.

Many attempts have been already proposed to improve the flaw of the former, which is easily damaged. For example, a method of coating an inorganic substance such as SiO _{2 on the} surface of a plastic substrate by vacuum deposition (Japanese Patent Laid-Open No. 58-204031) or providing a polyorganosilane-based hard coat film or an acrylic hard coat film on the surface of the plastic substrate. Method (USP3,986,997, USP4,211,823,
JP-A-57-168922, JP-A-59-38262, JP-A-59-51908, JP-A-59-51954, JP-A-59-51954
59-78240, JP 59-89368, JP 59-
102964, JP-A-59-109528, JP-A-59-12
0663, JP-A-59-155437, JP-A-59-1746
29, JP-A-59-193969, JP-A-59-204669
Gazette, etc.) is disclosed.

Improvement of surface hardness by vacuum deposition of inorganic substances such as SiO ₂ which is the above-mentioned conventional technology is high hardness, but adhesion to the base material,
There is a big problem that heat resistance, impact resistance, hot water resistance, light resistance, etc. are deteriorated.

Further, in order to improve and improve both the surface hardness and the antireflection property of the plastic, a method of coating a plastic substrate with about 1 micron of SiO ₂ by vacuum vapor deposition and further coating a multilayer antireflection film on it. Is disclosed.
(JP-A-56-113101).

Further, in JP-A-59-48702, JP-A-59-78301 and JP-A-59-78304, a polyorganosilane-based hard coat film or an epoxy resin cured film is formed on the surface of a plastic substrate. A method of coating an antireflection film made of an inorganic material on the coated layer is disclosed.

Further, the technology disclosed in JP-A-56-113101,
Although it has high hardness and antireflection property, it has a serious problem of lowering adhesion, heat resistance, impact resistance, hot water resistance, weather resistance and the like.

In addition, Japanese Examined Patent Publication No. 45-6193, Japanese Laid-Open Patent Publication No. 59-48702,
The techniques disclosed in JP-A-59-78301 and JP-A-59-78304 have antireflection properties, but on the other hand, they have insufficient adhesion to the base material and are deeply scratched and thick, and thus are used. It has a major drawback above. Further, there is a big problem in the adhesiveness after hot water immersion, the weathering adhesiveness, etc., which are easily immersed in water, alcohol and the like.

The conventional technologies have been reviewed above, but all of these technologies have problems with the adhesion between the hard coat layer on the base material and the vapor-deposited film (antireflection film) on the surface of the substrate. It has a defect that the (antireflection film) peels off like a scale.

[Problems to be Solved by the Invention] As a result of intensive studies made by the present inventors in order to solve the above problems, the inventors have reached the present invention described below.

That is, the present invention is particularly excellent in adhesion strength and durability, and also in scratch resistance, abrasion resistance, impact resistance, chemical resistance, flexibility, heat resistance, light resistance, weather resistance, antistatic property, etc. The present invention provides an optical article having an excellent multilayer antireflection film.

[Means for Solving Problems] That is, the present invention has the following configuration.

"A hard coat layer having abrasion resistance is provided on a transparent plastic substrate, and the surface layer thereof has a first layer, a layer containing zirconium oxide as a main component, and a second layer in order from the substrate side to the surface. A layer containing silicon dioxide as a main component; a third layer; a layer containing titanium oxide as a main component; a fourth layer; a layer containing silicon dioxide as a main component; and an equivalent film including the first layer and the second layer. An optical article having a multi-layer antireflection film, which is characterized by the above. ”In the present invention, it is first necessary to provide a hard coat layer having abrasion resistance on a plastic transparent substrate. Here, the plastic may be any known material. Further, the transparent substrate may be any as long as light can pass therethrough. For those used in front of displays such as word processors, visible light transmittance is 25 to 70% by dyeing or dyeing.
Are preferred. This is to reduce eye fatigue. The abrasion-resistant hard coat layer refers to a coating layer having high hardness such as polyorganosiloxane, silica, or alumina, or a layer containing an acrylic component.
This is because the surface of a plastic product is generally easily scratched, so that it is improved and undercoating of a multilayer antireflection film vapor-deposited or sputtered on the surface layer enhances adhesion. And particularly preferably, the hard coat layer is a polyorganosiloxane obtained by coating methyltrimethoxysilane and vinyltriethoxysilane, or a hydrolyzate thereof, followed by crosslinking and heat condensation.

The preferable film thickness of the hard coat layer is about 1 to 10 μm.

The acrylic hard coat layer refers to a layer obtained by crosslinking an acrylic compound such as methacrylic acid with an ester compound of a polyfunctional glycol such as pentaerythritol or glycerin.

Next, in the present invention, a layer containing zirconium oxide as a main component is first provided as a first layer on the surface layer of the hard coat layer. The layer containing zirconium oxide as a main component exerts an effect of improving the adhesion strength as a binder for both the lower hard coat layer and the upper layer containing silicon dioxide as a main component, and at the same time, it forms the second layer of silicon dioxide. By forming an equivalent film by combining with a layer containing
This is because it has a medium refractive index as compared with the layers and the fourth layer.

Next, in the present invention, a layer containing silicon dioxide as a main component is provided as a second layer on the surface layer of the first layer. The third layer is obtained by combining the first layer and the third layer with the effect of improving the adhesion strength, and at the same time combining the first layer with zirconium oxide as a main component to form an equivalent film. This is because it has a medium refractive index as compared with the fourth layer.

As described above, the first layer and the second layer are layers having a medium refractive index as a whole.

Next, a layer containing titanium oxide as a main component is provided as a third layer, and a layer containing silicon dioxide as a main component is provided thereon as a fourth layer. If a high refractive index layer is provided as the third layer and a low refractive index layer is provided as the fourth layer, a film having an excellent antireflection function is achieved in combination with the first and second medium refractive index layers. This is because that.

In the present invention, the first to fourth layers can be provided by vacuum vapor deposition or sputtering. More preferably, it is vacuum deposition. A method such as ion beam assist may be applied as appropriate. Further, titanium oxide or the like may be added to the first layer of zirconium oxide within a range that does not impair the effects of the present invention, and similarly, the second layer of titanium oxide may be mixed with Ta ₂ O ₅ or the like. Good.

The film thickness may be any thickness as long as it can prevent reflection of visible light. Preferred optical film thickness is, when a design wavelength lambda _0, the first layer in the range of 450~550nm; 0.05~0.15λ ₀ second layer; 0.05~0.15λ ₀ third layer; 0.36~0.49λ ₀ 4 Layer: 0.15 to 0.35λ ₀ . Of these, the fourth layer preferably has a thickness of 0.25λ ₀ .

In the present invention, the above multilayer antireflection film is provided on one surface or two surfaces of the plastic substrate. When provided on one surface, it is preferable to provide at least the hard coat described above in order to prevent scratches on the opposite surface. Further, the multilayer antireflection film of the present invention is provided on one surface, and a hard coat layer, an indium oxide / tin oxide layer (so-called ITO film) on the other surface.
Or a layer containing silicon dioxide as a main component may be provided on the ITO film, and one surface may be an antireflection layer and the other surface may be a layer having an electromagnetic wave shielding property. In the above, when an ITO layer is provided as the outermost layer, a relatively thin film (1
00-500Å) is preferable, and when a layer containing silicon dioxide as a main component is provided on the ITO film, a relatively thick film (for example, about 500-1000Å) is preferable.

A ground may be attached to the product of the present invention to remove static electricity. In this case, when the ITO film is present, it is preferable that the ground be directly taken from the ITO film or be in a conductive state. As another means, a metal frame may be attached around the product of the present invention to discharge static electricity. Also in this case, when the ITO film is present, the metal frame is preferably in direct contact with the ITO film or is in a conductive state.

This will be described below with reference to the drawings.

FIG. 1 shows a cross section of one embodiment of an optical article having a preferred multilayer antireflection coating of the present invention. Plastic transparent substrate
A hard coat layer 11 having abrasion resistance is provided on the surface 10, and the multilayer antireflection films 1 to 4 are further provided on the surface layer in order.

FIG. 2 shows the most approximate example of the prior art. That is, since the first layer of the multilayer antireflection film was yttrium oxide, it was easy to peel off at the interface between both the hard coat layer and the titanium oxide layer.

The application of the optical article having the multilayer antireflection film of the present invention is particularly effective as a filter for screens of televisions and displays (so-called optical filter). Other uses such as lenses for eyeglasses, films, and molded products can also be expected.

The multilayer film of the present invention can be formed by "Auger electron spectroscopy measurement method". In this method, a sample surface placed in a high vacuum is irradiated with an electron beam, and Auger electrons emitted from the surface are detected by energy division with an analyzer. The measurement conditions are as follows.

Measuring device: "JAMP-10S" manufactured by JEOL Ltd. When analyzing the outermost surface: 1 x 10 ^-7 Pa When analyzing in the depth direction: 6 x 10 ^-6 Pa (Ar atmosphere) Sampling: Hold the edge of the sample with a copper plate Fix on the sample table.

Acceleration voltage: 3.0KV Specimen current: 1 × 10 ^-8 A Beam diameter: 1 μm Slit: No.5 Specimen tilt angle: 40 to 70 degrees Ar ion etching conditions Acceleration voltage: 3.0KV Specimen voltage: 3 × 10 ^-7 A Etching Speed: 200 Å / min (in the case of SiO ₂ ) [Example] The following example will be described.

Example 1 A commercially available polymethacrylate plate (trademark "Aqualite" LN-084, gray original, thickness about 2 mm, manufactured by Mitsubishi Rayon Co., Ltd.) was used as a substrate. As the coating material for hard coat, as described in Example 1 of JP-A-59-114501, a coating obtained by hydrolyzing vinyltriethoxysilane with glacial acetic acid and a coating obtained by hydrolyzing methyltriethoxysilane with glacial acetic acid. The mixture was used. Sodium acetate, which is a curing agent, was added to this mixed solution, and a silicone-based surface smoothing agent was further added to obtain a coating material.

This coating material was applied on the front surface (front and back surfaces) of the substrate to a thickness of 2 μm, and heated and cured at 90 ° C. for 3 hours.

Next, this hard-coated plastic substrate was set in a vacuum vapor deposition tank, and after evacuation to 1 × 10 ^-5 TORR at a set temperature of 60 ° C., an argon ion beam was generated by a Kaofman type ion beam generator, Accelerating voltage 50
The substrate was cleaned at 0V. Subsequently, a four-layer film was formed on the front and back surfaces under the following conditions by the electron beam method in order from the substrate side.

(1) First layer; layer containing zirconium oxide as a main component, optical film thickness (nd) of about 42 nm, vacuum degree of 3 × 10 ^-5 TORR (oxygen introduction) (2) Second layer: containing silicon dioxide as a main component Layer, optical film thickness (nd) about 42 nm, vacuum degree 1 × 10 ^-5 TORR (3) 3rd layer; layer mainly containing titanium oxide, optical film thickness (nd) about 216 nm, vacuum degree 4 × 10 ^-5 TORR (introduction of oxygen) (4) Fourth layer; layer containing silicon dioxide as a main component, optical film thickness (nd) of about 120 nm, vacuum degree of 1 × 10 ^-5 TORR (however, above (1) In (4), the optical film thickness is 48
Use 0 nm. The product of the present invention obtained by the above method and conditions had a blue-violet reflection interference color and had an extremely excellent antireflection property with a surface reflectance at 550 nm of about 0.2%.

Further, a test was carried out by placing a square polyester knitted fabric having a hard surface and 2 cm on a side and squeezing tap water on the surface and rubbing it 2,000 reciprocations under a load of 2 kg, but no damage was observed.

Further, an exposure test was carried out by leaving it outdoors for one month, but there was no surface damage such as peeling of the antireflection film.

Further, when it was used as an optical filter of a word processor, it had an excellent antireflection function and had a remarkable effect in that the user's eyes were not tired.

It was also highly durable.

Further, the antistatic performance was measured as follows. In other words, the CRT (N
EC-KD551K) was set with a static electricity measuring instrument (Shishido Electrostatic Co., Ltd. “Statileon M”) at a position 53 mm in front, and the electrostatic potential when the switch of the personal computer was turned on was measured and the blank was 9 KV or more. . Next, install the product of the present invention with a ground attached between the CRT and "Statiron M" and at a distance of 30 mm from "Statiron M", and switch
The electrostatic potential when turned on was measured. As a result, within 30 seconds
It fell to 0.2 KV or less, and the antistatic effect was extremely excellent.

Comparative Example In Example 1, a three-layer film was formed under the following conditions instead of the four-layer film.

(1) First layer; layer containing yttrium oxide as a main component, optical film thickness (nd) about 120 nm, vacuum degree 3 × 10 ^-5 TORR (introduction of oxygen) (2) Second layer; titanium oxide as a main component Layer, optical film thickness (nd) about 216 nm, vacuum degree 4 × 10 ^-5 TORR (oxygen introduction) (3) Third layer; layer mainly composed of silicon dioxide, optical film thickness (nd) about The comparative product obtained by the above method at 120 nm and vacuum degree of 1 × 10 ⁻⁵ TORR was slightly inferior in antireflection property to the product of the present invention. However, in the cloth friction test evaluated in the same manner as the product of the present invention, partial peeling of the antireflection film occurred after about 100 times. Further, in an outdoor exposure test, a spot-like appearance or more occurred in about one week.

Further, when the antistatic performance was measured in the same manner as in Example 1, the electrostatic potential was lowered to about 1 KV even 10 minutes after the switch was turned on.

EFFECTS OF THE INVENTION Since the present invention is the technology as described above, it is particularly excellent in the adhesion strength and durability of a multilayer antireflection film, and has scratch resistance, abrasion resistance, impact resistance, chemical resistance, and good durability. An optical article having a multilayer antireflection film excellent in flexibility, heat resistance, light resistance, weather resistance, antistatic property, etc. could be obtained.

In particular, with regard to durability, it showed remarkable durability, and it became possible to use it in a stable state for a long period of time.

Also, as an unexpected effect, it showed extremely excellent antistatic effect.

[Brief description of drawings]

FIG. 1 shows a cross section of one embodiment of an optical article having a preferred multilayer antireflection coating of the present invention. FIG. 2 shows the most similar known example in the prior art. 1 to 4; multilayer antireflection film 10; transparent plastic substrate 11; hard coat layer

Claims (4)

[Claims] 1. A hard coat layer having abrasion resistance is provided on a transparent plastic substrate, and a surface layer thereof has a first layer; a layer containing zirconium oxide as a main component in order from the substrate side to the surface. A second layer; a layer containing silicon dioxide as a main component; a third layer; a layer containing titanium oxide as a main component; a fourth layer; a layer containing silicon dioxide as a main component; and the first layer and the second layer. An optical article having a multilayer antireflection film, characterized in that 2. When the optical thickness of the first layer to the fourth layer is a design wavelength λ ₀ , the first layer; 0.05 to 0.15 λ ₀ the second layer; 0.05 to 0.15 λ in the range of 450 to 550 nm. ₀ third layer; 0.36～0.49Ramuda ₀ fourth layer; optical article having a multilayer antireflection film of claims paragraph (1), wherein the 0.15~0.35λ is _0. 3. The first to fourth layers are vapor-deposited films or sputtered films.
An optical article having the multilayer antireflection film according to the item. 4. The optical article having a multilayer antireflection film according to claim 1, wherein the hard coat layer is a layer containing an organic polysiloxane.