JPH07104649A - Hologram - Google Patents

Abstract

PURPOSE:To provide a hologram which has a lightweight and simple structure and is easy to handle. CONSTITUTION:This hologram has a diffraction grating film 2 recorded with interference fringes and a substrate 5 disposed on one surface side of this diffraction grating film 2. Metallic foil 1 is stuck via an adhesive 3 to the surface of the diffraction grating film 2. The thickness of the metallic foil 1 is preferably 20 to 200mum. An Ni-Fe alloy, foil 1. The diffraction grating film 2 is a gelatin film, etc., recorded with the interference fringes. The adhesive 3 is preferably made black by adding a blackening agent, such as carbon black, thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram which is lightweight and has a simple structure and is easy to handle.

[0002]

2. Description of the Related Art A hologram diffracts and reflects incident light relating to a displayed image into reproduction light, which allows a viewer to visually recognize the display image. Conventionally, this hologram has a hologram dry plate 80 and a glass substrate 8 covering the hologram dry plate 80, as shown in FIG.
It consists of 5,86. The hologram dry plate 80 has a diffraction grating film 82 on which interference fringes are recorded, and a glass substrate 84 on which the diffraction grating film 82 is arranged. The glass substrate 86 has a non-reflective coating film or the like to improve the image quality. The glass substrate 85 protects the diffraction grating film 82 and imparts water resistance. Further, as shown in FIG. 8, there is also proposed a hologram using a glass substrate 85 that covers only the diffraction grating film 82 side of the hologram dry plate 80.

[0003]

However, the above-mentioned conventional hologram has a problem that the three or two glass substrates 84, 85 and 8 are used.
6 has a three-layer or two-layer structure. for that reason,
There is a problem that the hologram is thick and heavy. In view of the above conventional problems, the present invention aims to provide a hologram having a light weight and a simple structure.

[0004]

The present invention is a hologram having a diffraction grating film on which interference fringes are recorded and a substrate arranged on one side of the diffraction grating film, wherein the surface of the diffraction grating film is an adhesive. The hologram is characterized in that a metal foil is attached through the.

What is most noticeable in the present invention is that the surface of the diffraction grating film is covered with a metal foil. Basically, it is preferable that the thermal expansion coefficient of the metal foil is as close as possible to the thermal expansion coefficient (α = 9 × 10 ⁻⁶ ) of glass. However, since the metal foil is a thin film, it is possible to absorb a certain difference in expansion and contraction, so it is not necessary to approximate it so closely. Specifically, in the present invention, the thermal expansion coefficient of the metal foil is 5 × 10 ⁻⁶ to 15 × 10 ^−6.
It only needs to be within a range. For example, the metal foil may be Ni-Fe alloy, Ni-Cr alloy, Ni-Co-F.
e alloy, Ni-Cr-Fe alloy, mild steel, SUS430,
Or, there is titanium copper or the like.

The appropriate thickness of the metal foil varies depending on the difference in thermal expansion from the adhesive, the diffraction grating film, or the substrate, but is generally in the range of 20 to 200 μm and can be sufficiently adhered. . Further, if the thickness of the metal foil is too thin, pinholes are likely to occur, and there is a problem in quality reliability. On the other hand, if it is too thick, the steel is too strong,
The flexibility as a thin layer is lost and it becomes difficult to attach it to the diffraction grating film.

The metal foil is attached to the surface of the diffraction grating film with an adhesive. Examples of the adhesive include thermosetting adhesives such as epoxy-based, phenol-based, urethane-based, and silicone-based adhesives, and ultraviolet-curable adhesives such as acrylic-based adhesives. It is preferable that the adhesive be made black by adding a blackening agent such as carbon black. This makes it possible to absorb excess light that has passed through the hologram and prevent the generation of scattered light. Further, by blackening the adhesive, the transparency and refractive index adjustments required for ordinary hologram adhesives are not required, and the range of raw materials for the adhesive is wide. The blackening agent is preferably added to the adhesive in an amount of 5 to 40% by weight.

The substrate provided on one side of the diffraction grating film is not particularly limited as long as it can maintain the shape of the diffraction grating film, but a thin plate such as resin or glass is particularly used. Is preferred. The diffraction grating film is, for example, a gelatin film in which interference fringes are recorded.

In manufacturing the above hologram,
For example, a gelatin film in which a photosensitizer is dissolved is formed on a substrate and dried to form a hologram dry plate. Then, the hologram dry plate is exposed to record interference fringes on the gelatin film. Next, this hologram dry plate is developed. Next, an adhesive is applied to the surface of the hologram dry plate on the side of the diffraction grating film, and the metal foil is covered from above. Then, the adhesive is cured to obtain a hologram.

When the metal foil is attached to the surface of the diffraction grating film, it is preferable to continuously attach the metal foil in a tape shape to the hologram dry plate coated with the adhesive. Thereby, it is possible to prevent bubbles from being generated between the diffraction grating film and the metal foil. In addition, it is possible to reduce the protrusion of the adhesive,
It's very simple.

[0011]

In the hologram of the present invention, the surface of the diffraction grating film is covered with the metal foil. The metal foil is lighter in weight and thinner than the conventionally used substrate. Therefore, it is possible to reduce the weight and the thickness of the hologram. Further, the structure of the hologram can be simplified.

Since the metal foil is flexible, it can be easily bent. Therefore, the metal foil can be adhered to the surface of the diffraction grating film without mixing air bubbles between the metal foil and the diffraction grating film and without the adhesive agent interposed between the metal foil and the diffraction grating film protruding. Further, the metal foil can be easily and continuously attached to the diffraction grating film. Furthermore, it is easy to handle. Further, since the metal foil is highly water resistant, it is possible to prevent the surface of the diffraction grating film from coming into contact with water. According to the present invention, it is possible to provide a hologram which is lightweight and has a simple structure and which is easy to handle.

[0013]

Embodiments of the present invention will be described with reference to FIGS. As shown in FIG. 1, the hologram of this example includes a diffraction grating film 2 on which interference fringes are recorded, and the diffraction grating film 2
And a substrate 5 disposed on one side of the substrate. Diffraction grating film 2
The metal foil 1 is attached to the surface of the via the adhesive 3. As the metal foil 1, there is a 50Ni50Fe alloy (coefficient of thermal expansion 9.5 × 10 ⁻⁶ ) or a Ni—Cr alloy (coefficient of thermal expansion 12 × 10 ⁻⁶ ). The thickness of the metal foil 1 is 20 to
It is 200 μm.

The metal foil 1 is attached to the surface of the diffraction grating film 2 via an adhesive 3. As the adhesive 3, a water-resistant epoxy thermosetting adhesive for optics (cemedine C
S2340-5 or DSES- manufactured by Nippon Denki Co., Ltd.
1010) is used. In particular, the latter DSES-1010
Is an adhesive for printing and has high viscosity. Therefore, the adhesive can be applied without waste. The thickness of the adhesive is 5
˜100 μm. Further, the adhesive 3 is black by adding a blackening agent such as carbon black in an amount of 5 to 40% by weight.

The diffraction grating film 2 is a dichromate gelatin film on which interference fringes are recorded and has a film thickness of 10 μm to 40 μm. The refractive index of the diffraction grating film 2 is about 1.55. The substrate 5 is a transparent soda glass, 112 mm x 4
The size is 6 mm × 1.8 mm. Refractive index is 1.5
It is 2. On the surface of the substrate 5 on the atmosphere side, MgF ₂ and Ti
An antireflection film 52 formed by alternately stacking O ₂ is formed.

The hologram 10 is used, for example, in the head-up display device 9 shown in FIG. In this device 9, the hologram 10 diffracts / reflects the light 30 emitted from the display 90 and irradiates the diffracted light 31 on the reflection film 92 to make the viewer 95 visually recognize the display image 94.

A method of manufacturing the hologram 10 will be described below with reference to FIGS. First, 112mm
A dichromate gelatin film as a photosensitive film 20 having a thickness of 25 μm is formed on a substrate 46 of × 46 mm × 1.8 mm. The photosensitive film 20 is 0.6 g in 100 ml of 4% gelatin solution.
Is a solution of ammonium dichromate and has a refractive index of about 1.55. Next, the substrate 5 having the photosensitive film 20 formed thereon was left to be stabilized in a dryer maintained in an atmosphere of 20 ° C. and 50% RH for 72 hours.

Then, with the configuration of FIG.
The argon laser light of m is regenerated (when the incident angle is 33.5) by changing the incident angle so as to have two colors of 540 nm and 600 nm. A recorded diffraction grating film was obtained. The focal length of the lens 66 in FIG.
It was 0 mm.

Here, in order to record an object on the photosensitive film 20, generally, as shown in FIG. 3, the substrate 5 on which the photosensitive film 20 is formed is placed between a lens 66 having a certain focal length and a prism 67. It is sandwiched with the refraction adjusting liquid 65 interposed therebetween. Silicon oil is used as the refraction adjusting liquid 65.

Argon laser light having a wavelength of 514.5 nm is incident as incident light 68 from the prism 67 side. Since the refractive index is uniform after the incidence, the incident light 68 is incident on the lens 6
Then, the light travels linearly to the 6 side and is reflected by the reflection film 660 formed on the surface of the lens 66 on the atmosphere side. The reflected light 69 and the incident light 68 interfere with each other on the photosensitive film 20.
As a result, interference fringes are recorded on the photosensitive film 20. A part of the reflected light 69 that has passed through the photosensitive film 20 is part of the substrate 5
Then, the light passes through the refractive index adjusting liquid 65 and enters the prism 67. Then, a part of the reflected light 69 is reflected on the incident surface of the prism 67.

In this case, the angle α of the incident surface of the prism 67 is
Is adjusted to be 30 ° with respect to the incident light 68 so that the reflected light 69 on the incident surface of the prism 67 does not travel toward the photosensitive film 20. By disposing such a prism 67, it is possible to remove display noise due to the reflected light 69 at the interface that causes noise. It is possible to prevent the reflected light 19 on the incident surface of the prism 67 from advancing toward the photosensitive film 20 by applying a black coating that absorbs light to the side surface of the prism 67. As a result, when copying and recording the lens 66 on the photosensitive film 20,
No noise image is recorded.

After the exposure, the substrate 5 is washed with water until the color disappears, and a commercially available photographic hardener fixing solution (Kodak Rapid.
It was immersed in a fixer) for 10 minutes. After washing with water, soak in 90% and then 100% isopropanol for 10 minutes,
It was dried with hot air. After that, heat aging was performed at 150 ° C. for 4 hours so that the wavelength did not change in the usage environment.
In this way, a diffraction grating film having interference fringes recorded is obtained.

Thereafter, as shown in FIG. 4, the diffraction grating film 2
Of the seal width S on the outer periphery of the diffraction grating film 2
To provide. Thereby, the diffraction grating film 2 and the diffraction grating film 2
A hologram dry plate 11 composed of the substrate 5 on which is provided is obtained. The seal width S varies depending on the water resistance of the adhesive 3 and the use environment, but is preferably about 3 to 8 mm.

Next, as shown in FIG. 5, an adhesive was printed on the hologram dry plate 11 using the metal foil sticking device 7 to stick the metal foil 1. That is, first, the adhesive 3 is printed on the entire surface of one side of the substrate 5 coated with the diffraction grating film 2 with a uniform thickness in the range of 5 to 100 μm using the printing machine 30 and the roller 31. Or apply. As a result, in the subsequent metal foil sticking step, it is possible to prevent the adhesive from sticking out and sink marks, and stick the metal foil 1 in parallel with the diffraction grating film 2.

As the adhesive 3, as described above, the water-resistant and highly viscous printing DSES-1010 was used.
Then, the blackening agent is added in advance therein. In addition, on the surface of the substrate 5, 1 mm from the side
To some extent, it is better not to print or apply the adhesive 3. This is to prevent the adhesive from squeezing out when pressing the hologram dry plate 11 and the metal foil 1 described later.

On the other hand, while the tape-shaped metal foil 1 wound around the roller 71 is sequentially fed by the rollers 72 to 74,
The adhesive 3 is attached to the surface of the printed substrate 5. At this time, the adhesive 3 and the metal foil 1 may be temporarily pressed against the surface of the roller 74. As a result, the adhesive 3 and the metal foil 1 can be brought into close contact with each other without mixing bubbles.

After sticking, 100 to 120 ° C., 30 minutes to 6
Heat for 0 minutes to cure the adhesive 3. Next, the portion of the tape-shaped metal foil 1 that is bonded to the substrate 5 is cut out. After that, an antireflection film is formed on the surface of the substrate 5 on the atmosphere side. As a result, the hologram 10 shown in FIG. 1 is formed.

Next, the function and effect of this example will be described.
In the hologram 10 of this example, the surface of the diffraction grating film 2 is covered with the metal foil 1. The metal foil 1 is lightweight and thin. Therefore, it is possible to reduce the weight and the thickness of the hologram 10. Also, the hologram 10
The structure of can be simplified.

Further, since the metal foil 1 is easily curved,
It is possible to absorb some distortion. It is also easy to handle. Therefore, the metal foil 1 can be easily and continuously attached to the diffraction grating film 2. Also, metal foil 1
Has a high water resistance, so that it is possible to prevent moisture from coming into contact with the surface of the diffraction grating film 2. Further, in this example, since the surface of the substrate 5 is covered with the antireflection film 50, problems such as noise due to surface reflection can be avoided.

[Brief description of drawings]

FIG. 1 is a sectional view of a hologram of an example.

FIG. 2 is a sectional view of a substrate on which a diffraction grating film is formed according to an embodiment.

FIG. 3 is an explanatory diagram showing a recording method of interference fringes according to the embodiment.

FIG. 4 is a sectional view of the hologram dry plate according to the embodiment.

FIG. 5 is an explanatory view showing a method of attaching a metal foil to a hologram dry plate according to the embodiment.

FIG. 6 is a principle diagram of a head-up display according to the embodiment.

FIG. 7 is a sectional view of a conventional hologram.

FIG. 8 is a sectional view of another hologram of the conventional example.

[Explanation of symbols]

 1. ． ． Metal foil, 10. ． ． Hologram, 11. ． ． Hologram plate, 2. ． ． Diffraction grating film, 3. ． ． Adhesive, 5. ． ． Substrate, 7. ． ． Metal foil sticking device,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Tatebayashi, 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor, Yasuhiro Mizutani, 1-1, Showa-cho, Kariya city, Aichi prefecture Incorporated (72) Inventor Tomonori Ishikawa 1-1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (6)

[Claims] 1. A hologram having a diffraction grating film on which interference fringes are recorded and a substrate arranged on one side of the diffraction grating film, wherein the surface of the diffraction grating film is a metal foil via an adhesive. A hologram characterized by being attached. 2. The hologram dry plate according to claim 1, wherein the metal foil has a thickness of 20 to 200 μm. 3. The metal foil according to claim 1, wherein the metal foil is Ni.
-Fe alloy, Ni-Cr alloy, Ni-Co-Fe alloy,
A hologram dry plate comprising one or more metals selected from the group consisting of Ni-Cr-Fe alloy, mild steel, SUS430, and titanium-copper. 4. The hologram according to claim 1, wherein the adhesive is black. 5. The diffraction grating film according to claim 1, wherein:
A hologram dry plate characterized by being a gelatin film. 6. The material according to claim 1, wherein the adhesive is selected from the group consisting of epoxy-based, phenol-based, urethane-based, or silicone-based thermosetting adhesives and acrylic-based ultraviolet-curing adhesives. Is a hologram.