JPH09251105A - Composite mirror, manufacture thereof and observation device using composite mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive composite mirror having good reflectivity in visible light for observation and transmissivity in infrared light for detecting a line of sight. SOLUTION: A visible light beam L1 for observing a liquid crystal screen A is reflected by a composite mirror 20 provided on the front surface 1c of an enlarging optical element 1, reaches an observer's eye B, an infrared light beam L2 in a line-of-sight detecting system 30 is reflected by the observer's eye B, transmitted through the composite mirror 20 and detected by a photodetector 33. The composite mirror 20 is formed by laminating a metallic mirror film on a red dichroic mirror, the red dichroic mirror is locally exposed by providing an aperture 23 in the metallic mirror film and it is constituted that only this part has the transmissivity for infrared light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compound mirror for an observing device for observing a photographed image of a photographing device such as a head mounted display or a video camera for magnifying and observing a liquid crystal image, a manufacturing method thereof, and the compound mirror. The present invention relates to the observation device used.

[0002]

2. Description of the Related Art An optical system of an observing device mounted on a photographing device such as a head mounted display or a video camera for enlarging and observing a liquid crystal image or the like reflects visible light of an image toward an observer's eye. Then, it is provided with a compound mirror that transmits infrared light for detecting the line of sight of the observer. As such a composite mirror, a red dichroic mirror having a selective transmission property that transmits only infrared light, or a metal half mirror configured to transmit a part of light by reducing the film thickness of the metal reflection film is used. Is common.

[0003]

However, according to the above-mentioned conventional technique, a red dichroic mirror having a selective transmission property for transmitting only infrared light has a dielectric structure in which high refractive index films and low refractive index films are alternately laminated. It is a multi-layer film, and it is necessary to increase the number of layers to obtain high reflectance in a wide visible light range. However, increasing the number of layers increases the manufacturing cost and also increases the polarization characteristics of the dielectric multi-layer film. It becomes difficult to obtain the desired selective permeability due to the decrease in That is, it is extremely difficult to realize an inexpensive dichroic mirror that has a high reflectance and the required selective transmittance.

Further, the metal half mirror has a tendency that the transmittance of infrared light decreases as the reflectance of visible light increases.

As described above, according to the conventional technique, it is not possible to obtain a composite mirror that is satisfactory in both optical characteristics and price.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has a high reflectance for visible light for observation and a selective transmission property for infrared light for detecting a line of sight. It is an object of the present invention to provide a composite mirror which is excellent and inexpensive, a manufacturing method thereof, and an observation device using the composite mirror.

[0007]

In order to achieve the above object, a composite mirror of the present invention has a selective transmission film provided on the surface of a substrate and a metal mirror film laminated thereon.
It is characterized in that the metal mirror film has an opening for locally exposing a predetermined portion of the selective transmission film.

The selective transmission film is preferably a red dichroic mirror that reflects visible light and selectively transmits infrared light.

It is preferable that the metal mirror film has a metal film having a high reflectance for visible light.

The opening of the metal mirror film is preferably an opening having a diameter of 2 mm or less.

The method of manufacturing a composite mirror of the present invention comprises a step of forming a selective transmission film on the surface of a substrate, a step of providing a pattern of a low adhesion film on the produced selective transmission film, and a pattern of a low adhesion film. The method is characterized by including a step of laminating a metal mirror film on the selective transmission film provided with, and a step of peeling a part of the laminated metal mirror film together with the pattern of the low adhesion film.

[0012]

[Function] The reflectance of the composite mirror with respect to visible light, etc. is extremely high, with the high reflectance of the metal mirror film added to the reflectance of the selective transmission film, in most of the remaining portion except the opening of the metal mirror film. Becomes On the other hand, the opening of the metal mirror film does not impair the selective transmittance of the selective transmission film with respect to infrared light or the like, and therefore, the infrared light or the like for detecting the line of sight of the observer can be transmitted with high transmittance. You can

If the opening of the metal mirror film is an opening having a diameter of 2 mm or less, the case where the opening is not formed in the metal mirror film without causing a hollow in the image seen by the observer. Similar images can be observed.

As described above, in most of the composite mirrors, a high reflectivity utilizing the reflectivity of the metal mirror film is secured, and the selective transmission film is locally exposed from the opening of the metal mirror film to select the film. By effectively utilizing the transmissivity, it is possible to realize a composite mirror having high reflectance for visible light for observation and excellent selective transmissivity for infrared light.

Since the metal mirror film and the selective transmission film may be individually designed based on the respective required optical characteristics, there is no fear that the number of layers as a whole or the design becomes difficult,
Therefore, the manufacturing cost is low.

A step of forming a selective permeable film on the surface of the substrate, a step of providing a pattern of the low adhesion film on the produced selective permeable film, and a step of forming a metal on the selective permeable film provided with the pattern of the low adhesion film. According to the method for manufacturing a composite mirror having a step of laminating a mirror film and a step of peeling a part of the laminated metal mirror film together with the pattern of the low adhesion film, the pattern of the low adhesion film before the metal mirror film is laminated. By depositing on the selective transmission film, laminating the metal mirror film, and then peeling off a part thereof together with the pattern of the low adhesion film,
The opening of the metal mirror film can be easily formed.

By using such a composite mirror, it is possible to greatly contribute to high performance and low cost of the observation device.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an observation apparatus according to an embodiment, which is a prism-shaped substrate 10 which is an observation optical system.
The magnifying optical element 1 having The base body 10 of the magnifying optical element 1 is integrally molded of a resin material such as an acrylic resin, a polycarbonate resin, or a polyolefin resin, and is visible light that is the first light reflected from the liquid crystal screen A that is the object to be observed. L ₁ is incident on the entrance surface 1a of the magnifying optical element 1, is totally reflected by the total reflection surface 1b, is internally reflected by the reflection surface 1c, and then passes through the total reflection surface 1b to reach the observer's eye B. To do.

On the surface of the reflecting surface 1c of the magnifying optical element 1,
As shown in FIG. 1B, a composite mirror 20 is provided, and the composite mirror 20 has a base body 1 as shown in FIG.
It is composed of a dielectric multilayer film 21 which is a selective transmission film laminated on 0 and a metal mirror film 22 which is laminated thereon. The dielectric multilayer film 21 is a red dichroic mirror in which two low refractive index films 21a and two high refractive index films 21b are alternately laminated, and the metal mirror film 22 includes a base film 22a, an aluminum metal film 22b, and a protective film. The film 22c is laminated, and a plurality of openings 2 are formed in the central portion and the outer peripheral portion of the composite mirror 20.
3

The metal mirror film 22 reflects the visible light L ₁ of the liquid crystal screen A with high reflectance to reach the eye B of the observer, and each opening 23 is generally smaller than the pupil diameter of the eye. It is a circular hole having a diameter of 2 mm or less, and is configured so that a hollow image does not occur in the image of the liquid crystal screen A observed by the observer.

The infrared light L ₂ which is the second light generated from the light source 31 of the visual axis detection system 30 enters the magnifying optical element 1 through the opening 23 at the outer peripheral portion of the compound mirror 20, and is a total reflection surface. The light passes through 1b to reach the observer's eye B, is reflected there, enters the magnifying optical element 1 again, and is taken out through the opening 23 at the central portion of the compound mirror 20 to form the imaging lens system 3
After passing through 2, the light enters the light receiving element 33.

That is, while the observer observes the liquid crystal screen A as an image magnified by the magnifying optical element 1, the infrared light L ₂ of the line-of-sight detection system 30 passes from the observer's eye B to the magnifying optical element 1. The line of sight of the observer is detected by moving backward and detecting by the light receiving element 33.

As described above, almost the entire composite mirror 20 is a laminated body of a dielectric multilayer film (red dichroic mirror) 21 having a selective transmittance for infrared light and a metal mirror film 22 having a high reflectance. Therefore, the metal mirror film 22 ensures high reflection characteristics for the visible light L _{1, and} an opening 23 is provided in a portion of the metal mirror film 22 that needs to selectively transmit infrared light, and only this portion is red. Since it is configured to function as a dichroic mirror, it has high reflection characteristics for visible light for observation, sufficient selective transmission of infrared light, and the total number of layers is small A low cost composite mirror can be realized. By using such a composite mirror, it is possible to greatly contribute to high performance and low cost of observation devices such as head mounted displays and video cameras.

Dielectric multilayer film (red dichroic mirror)
Is composed of alternating layers of a low-refractive index film and a high-refractive index film as described above, and low-refractive-index film materials include SiO, SiO ₂ , MgF ₂ ,
Al ₂ O ₃ or the like is used. Among these, a SiO film or a SiO ₂ film of silicon oxide is preferable as the first layer because it has good adhesion to the resin forming the base of the magnifying optical element and can alleviate deformation due to thermal expansion or hygroscopic expansion. ZrO ₂ , TiO ₂ , Ta ₂ O ₅ , ZnS, a mixture thereof, or the like is used as the high refractive index film material. Among these, a mixture containing TiO ₂ as a main component, which has a low melting point and a high refractive index even without heating, is suitable.

The material of the metal mirror film is aluminum or silver which has a high reflectance in the visible light range and can obtain flat optical characteristics. The base film is selected from SiO, SiO ₂ , Cr, etc., which have good adhesion to the resin substrate, the dielectric multilayer film, the metal mirror film, etc., and the protective film is preferably SiO, Cr, Al ₂ O ₃ etc. .

When a sufficient reflectance can be obtained only by the metal mirror film, the dielectric multilayer film is omitted and the metal mirror film is directly laminated on the surface of the substrate, and the diameter of 2 m is applied to the metal mirror film.
Infrared light may be transmitted by providing an opening of m or less.

The method of forming an opening in the metal mirror film is as follows. The pattern of the low adhesion film is deposited using a known water repellent material directly on the surface of the substrate or after providing the dielectric multilayer film (shown by the broken line in FIG. 2). A metal mirror film is laminated on it, and then the pattern of the low adhesion film is peeled off together with the metal mirror film on it.

Next, a specific example will be described.

First Specific Example The first example is formed on the surface of a prism-shaped substrate made of acrylic resin.
As a layer, a low-refractive-index film made of SiO 2 having a thickness of 130 nm
145nm high refractive index film composed of a mixture of TiO ₂ as a main component as a layer 130 nm, a low refractive index film made of SiO as a third layer, a high refractive index composed of a mixture of TiO ₂ as a main component as the fourth layer A film of 130 nm is formed and 4
A dielectric multilayer film (red dichroic mirror) having a layer film structure was formed. Through a mask having three openings each having a diameter of 1 mm, a film material having water repellency was provided by O
F-110 was deposited to a thickness of 1 nm to form a low adhesion film pattern. Next, the mask is removed, and the base film made of SiO is 100 nm and the metal film made of aluminum is 100 n.
A protective film made of m and SiO was formed to a thickness of 10 nm to form a metal mirror film having a three-layer film structure. Next, the metal mirror film on the low adhesion film was peeled off with a cellophane tape to fabricate a composite mirror having three openings in the metal mirror film.

FIG. 3 is a graph showing the spectral reflectance of the composite mirror on the inner surface side of the substrate, and FIG. 4 is a graph showing the spectral transmittance of the opening. As can be seen from these figures, the inner surface reflectance of the composite mirror is as high as 97% at a wavelength of 500 nm and the visible light region is uniform, and the aperture portion has a visible light region reflectance of 58% and infrared light transmission. The rate is 94%. As a result of the quality evaluation test, the appearance, solvent resistance, adhesion resistance, positional accuracy of openings, and shape accuracy of the composite mirror were good.

Second Specific Example A low-refractive-index film made of SiO 2 as a first layer is formed on the surface of a prism-shaped substrate made of polycarbonate resin as a first layer.
m, a high refractive index film made of a mixture containing TiO ₂ as a main component was formed to a thickness of 130 nm as a second layer to form a dielectric multilayer film (red dichroic mirror) having a two-layer film structure. Next, as a water-repellent film material through a mask having three openings with a diameter of 1 mm on the dielectric multilayer film, O
F-110 was deposited to a thickness of 1 nm to form a low adhesion film pattern. The mask is removed and the underlying film made of SiO 2 is removed.
0 nm, 100 nm metal film made of aluminum, S
A protective film made of iO was formed to a thickness of 10 nm to form a metal mirror film having a three-layer film structure. Next, the low-adhesion film and the metal mirror film on the low-adhesion film were peeled off with a cellophane tape to fabricate a composite mirror having three openings.

The internal reflectance of this composite mirror has a wavelength of 500.
93% in nm, the reflectance in the visible light region of the aperture is 3
The transmittance of 0% and infrared light is 85%. Further, the results of the quality evaluation test were also good in appearance, solvent resistance, adhesion resistance, positional accuracy of openings, and shape accuracy as in the first specific example.

Third Specific Example A pattern of a low adhesion film was formed on the surface of a prism-shaped substrate made of acrylic resin by spray coating a water-repellent material through a mask having three openings with a diameter of 1 mm. Next, the mask is removed, the base film made of SiO is 200 nm, the metal film made of Cr is 2 nm, the metal film made of silver is 150 nm, and the metal film made of Cr is 10 n.
m, a protective film of Al ₂ O ₃ having a thickness of 150 nm and a protective film of SiO having a thickness of 10 nm were formed to form a metal mirror film having a 6-layer film structure. Next, the low-adhesion film and the metal mirror film on it were peeled off with cellophane tape to fabricate a composite mirror having three openings.

The internal reflectance of this composite mirror has a wavelength of 500.
97% in nm, the infrared transmittance of the aperture is 96
%. Also, the results of the quality evaluation test are the same as those in the first specific example, such as appearance, solvent resistance, adhesion resistance and opening position accuracy,
The shape accuracy was also good.

Fourth Embodiment A surface of a prism-shaped substrate made of acrylic resin is spray-coated with a water-repellent material through a mask having five openings with diameters of 1 mm and 1.2 mm to form a low adhesion film. A pattern was formed. Then, the mask was removed, and a base film made of SiO was formed to 100 nm, a metal film made of aluminum was formed to 100 nm, and a protective film made of SiO was formed to 10 nm to form a metal mirror film having a three-layer film structure. Next, the low adhesion film and the metal mirror film on the low adhesion film were peeled off with a cellophane tape to manufacture a composite mirror having five openings.

The internal reflectance of this composite mirror has a wavelength of 500.
86% in nm, the infrared transmittance of the aperture is 96
%. Also, the results of the quality evaluation test are the same as those in the first specific example, such as appearance, solvent resistance, adhesion resistance and opening position accuracy,
The shape accuracy was also good.

Next, the following composite mirror was manufactured for comparison.

Comparative Example Si was formed on the surface of a prism-shaped substrate made of acrylic resin.
A low-refractive-index film made of O and a high-refractive-index film made of a mixture containing TiO ₂ as a main component are alternately laminated in a film thickness range of 100 nm to 200 nm to form a dielectric multilayer film (red dichroic mirror) having an 11-layer film structure. ) Was formed.

The reflectance in the visible light region was 70% at a wavelength of 500 nm, and the transmittance for infrared light was 85%. In addition, fine film cracks appeared in appearance.

Table 1 summarizes the results of the quality evaluation tests performed on the composite mirrors of the first to fourth specific examples and the composite mirror of the comparative example.

[0042]

[Table 1] ⊚: Good ○: No problem in practical use Δ: Not practically applicable Note that the reflectance in the quality evaluation test is the internal reflectance (%) of the composite mirror with respect to visible light having a wavelength of 500 nm, and the transmittance is 880 nm at the aperture of the composite mirror. Is the transmittance (%) of infrared light, and the appearance is the result of a visual inspection for abnormalities such as spiders, film cracks, and film peeling. Solvent resistance was examined by using Silbon paper soaked in a mixture of alcohol and freonsolve for abnormal appearance after 10 reciprocations under a load of 500 g / cm ² , and adhesion resistance was measured on the surface of the composite mirror. After the cellophane tape was attached and quickly peeled off, the presence or absence of peeling of the film was examined.

[0043]

Since the present invention is configured as described above, it has the following effects.

It is possible to inexpensively manufacture a composite mirror having a high reflectance for visible light for observation and excellent in selective transmission for infrared light for detecting a line of sight. By using such a composite mirror, it is possible to greatly contribute to the cost reduction and the high performance of the observation device such as the head mounted display and the video camera.

[Brief description of drawings]

FIG. 1 shows an observation apparatus according to an embodiment, (a)
Is a diagram for explaining the overall configuration, and FIG. 6B is a side view showing only the magnifying optical element.

FIG. 2 is a diagram showing a film structure of a composite mirror.

FIG. 3 is a graph showing a spectral characteristic of reflectance of a first specific example of a composite mirror.

FIG. 4 is a graph showing the spectral characteristics of the transmittance of the aperture of the above specific example.

[Explanation of symbols]

 1 Magnifying Optical Element 10 Substrate 20 Composite Mirror 21 Dielectric Multilayer Film 22 Metal Mirror Film 23 Aperture

Claims (10)

[Claims] 1. A permselective membrane provided on the surface of a substrate,
A composite mirror having a metal mirror film laminated thereon, the metal mirror film having an opening for locally exposing a predetermined portion of the selective transmission film. 2. The composite mirror according to claim 1, wherein the selective transmission film is a red dichroic mirror that reflects visible light and selectively transmits infrared light. 3. The composite mirror according to claim 1, wherein the metal mirror film has a metal film having a high reflectance for visible light. 4. The composite mirror according to claim 1, wherein the opening of the metal mirror film is an opening having a diameter of 2 mm or less. 5. The selective transmission film is a dielectric multilayer film in which a predetermined number of high refractive index films and low refractive index films are alternately laminated, and the material thereof is SiO, SiO ₂ , MgF ₂ , Al ₂ O ₃ , Z
5. The composite mirror according to claim 1, wherein the composite mirror is selected from rO ₂ , TiO ₂ , Ta ₂ O ₅ , ZnS and a mixture containing at least one of them. 6. The composite mirror according to claim 1, wherein the metal mirror film has a metal film made of aluminum or silver. 7. A composite mirror, comprising a metal mirror film laminated on the surface of a substrate, wherein the metal mirror film is provided with an opening having a diameter of 2 mm or less. 8. A step of producing a selective permeable film on the surface of a substrate, a step of providing a pattern of a low adhesion film on the produced selective permeable film, and a step of forming a pattern of the low adhesion film on a selective permeable film. A method of manufacturing a composite mirror, comprising: a step of laminating a metal mirror film on the substrate; and a step of peeling a part of the laminated metal mirror film together with the pattern of the low adhesion film. 9. A compound mirror according to claim 1, and an observation optical system for reflecting the first light for observing an object to be observed by the compound mirror to reach an eye of an observer. An observation apparatus having a line-of-sight detection system that reflects the second light for detecting the line-of-sight to the eyes of the observer and then transmits the second light to the light-receiving element through the composite mirror. 10. The observation apparatus according to claim 9, wherein the first light is visible light and the second light is infrared light.