JPH07104640A - Hologram - Google Patents

Abstract

PURPOSE:To provide a hologram having a large area of a diffraction grating film and excellent water resistance. CONSTITUTION:This hologram consists of the diffraction grating film 21 recorded with interference fringes, a glass substrate 22 disposed one surface side of the diffraction grating film 21 and cover plates 51, 52 disposed on the surface of the diffraction grating film 21 via an adhesive 6. The flank parts 15 of the hologram 17 are coated with water repellent layers 1. The hologram may also be composed of the diffraction grating film 21 recorded with the interference fringes, the glass substrate 22 disposed on one surface side of the diffraction grating film 21 and the water repellent layers 1 coating the surfaces of the diffraction grating film 21. The water repellent layers 1 consist of an epoxy resin, phenolic resin, butyral resin, acrylic resin, etc. The water repellent layers 1 are preferably impregnated with an impregnating agent such a wax, etc. A moistureproof treating agent is usable for the water repellent layers 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram having a large diffraction grating film and excellent water resistance.

[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. This hologram is used in a head-up display device, for example, as shown in FIG. The head-up display device includes a display device 90 having a light source, a hologram 91 that diffracts / reflects the light 30 emitted from the display device 90, and a diffracted light 31 from the hologram 91 that is reflected by a viewer 93.
And a windshield 92 for visually recognizing the display image 94. The windshield 92 has the diffracted light 31
A vapor deposition film 921 that reflects light is vapor-deposited.

The hologram 91, as shown in FIG.
A glass substrate 912 provided with the diffraction grating film 97, and cover plates 913, 914 sandwiching the glass substrate 912.
Consists of. The cover glass 913 contributes to the improvement of image quality by using a non-reflection coated glass or the like. Further, the cover glass 914 imparts water resistance to the hologram 911. The glass substrate 912 is sealed between the cover glasses 913 and 914 by the adhesive 910. As shown in FIGS. 12 and 13, a seal width S is provided on the outer peripheral portion 20 of the diffraction grating film 910, and the diffraction grating film 97 is sealed with an adhesive 910.

In manufacturing the above hologram,
As shown in FIGS. 12 and 13, a diffraction grating film 97 on which interference fringes are recorded is formed on the glass substrate 912. Then,
The outer peripheral portion 20 of the diffraction grating film 97 is removed as the seal width S. Then, the diffraction grating film 97 and the glass substrate 912
An adhesive agent 910 is applied to the outer peripheral portion of the, and a cover glass 914 is attached and fixed from above. Further, an adhesive 910 is applied to the surface of the glass substrate 912 opposite to the diffraction grating film 97, and the cover plate 913 is attached. Thereby, the hologram 91 is obtained.

[0005]

However, in the above-mentioned conventional hologram, in order to protect the diffraction grating film 97 against the humidity of the surrounding environment, the outer peripheral portion 20 of the diffraction grating film 97 is protected.
Moreover, a seal width S of 3 to 8 mm is indispensable. Due to this seal width, the diffraction grating film 97 has a much smaller area than the hologram. Therefore, the display area of the display image 94 is limited. Further, in order to reduce the seal width S, the adhesive 910 itself needs to be improved. For that,
It takes a lot of time and money. In view of such conventional problems, the present invention aims to provide a hologram having a large-area diffraction grating film and excellent water resistance.

[0006]

The present invention has a diffraction grating film on which interference fringes are recorded, and a substrate disposed on one side of the diffraction grating film, and the surface of the diffraction grating film is bonded via an adhesive. A hologram comprising a cover plate provided, wherein the side surface of the hologram is covered with a water repellent layer.

In the present invention, the water repellent layer has a low water permeability or a property of repelling water, and covers the side surface of the hologram. The water-repellent layer has no optical restrictions such as transparency, color, and refractive index, and the range of selection of raw materials used for the water-repellent layer is large. For example, the water-repellent layer is made of epoxy resin, phenol resin, butyral resin, acrylic resin, silicone resin, urethane resin, fluororesin, etc., and is formed by various methods such as dipping method, spraying method and brush coating method. It is formed on the side surface.

The thickness of the water repellent layer is not particularly limited,
50 to 1000 μm is preferable. If it is less than 50 μm, the water resistance of the hologram and the strength of the water repellent layer may be reduced. On the other hand, when it exceeds 1000 μm, it becomes difficult to achieve the object of the present invention.

An impregnating agent such as wax or paraffin is preferably added to the water repellent layer. Thereby, the micropores existing in the resin portion of the water repellent layer can be completely sealed with the impregnating agent. Therefore, the water repellency of the water repellent layer can be further enhanced, and the water resistance of the hologram can be improved. For example, a phenol resin having a thickness of 0.5 to 1 mm is impregnated with wax at 100 to 140 ° C. for 10 to 60 minutes. As a result, a water repellent layer having high water repellency is formed.

As the water repellent layer, a moisture-proof treatment agent such as modified acrylic, polyolefin, butyl modified rubber, vinyl, or fluoroacrylate can be used. This moistureproofing agent is generally used to impart water resistance to an IC substrate. The moisture-proof treatment cannot be expected to be as water repellent as the phenol resin, but can reduce the seal width to about 3 mm.

The moistureproofing agent is used by applying a liquid sealing agent on the side surface of the hologram and naturally drying. The thickness of the moistureproofing agent is preferably 10 to 500 μm. If it is less than 10 μm, the water resistance of the hologram and the strength of the water repellent layer may be reduced. On the other hand, 500 μm
If it exceeds, it becomes difficult to achieve the object of the present invention. It is preferable to heat the moisture-proof treatment agent to about 70 ° C. As a result, the solvent in the moistureproofing agent is more firmly attached to the outer peripheral portion of the hologram.

As the adhesive agent for adhering the substrate and the cover plate to each other, an ultraviolet curable adhesive such as acrylic resin or a thermosetting adhesive such as epoxy resin or phenol resin can be used. Among these, it is particularly preferable to use an ultraviolet curing adhesive. Thereby, the substrate and the cover plate can be bonded to each other without heating the hologram.

Interference fringes are recorded on the diffraction grating film. In the method of recording the interference fringes, for example, light beams having different phases are incident on a photosensitive film containing a photosensitizer from two directions, so that the two light beams interfere with each other on the photosensitive film. After recording, it is usually developed and sealed with adhesive and cover plate.

The substrate is made of glass, resin or the like and is used as a hard plate or a flexible film. The cover plate is used as one or a plurality of sheets and is attached to one side or both sides of the substrate. For example,
When one cover plate is arranged on one side, the hologram has a two-layer structure of a substrate and a cover plate.
When one cover plate is provided on each side, a three-layer structure composed of a substrate and two cover plates is adopted. Also, a plurality of cover plates may be provided on both sides. As the cover plate, glass,
Resin, metal foil, etc. are used.

A water repellent layer may be formed by subjecting the adhesive to a water repellent treatment. Such a hologram includes, for example, a diffraction grating film having interference fringes recorded thereon, a substrate provided on one side of the diffraction grating film, and a water-repellent layer covering the surface of the diffraction grating film. There is a hologram to do.

The water repellent treatment is performed by adding an impregnating agent such as wax or paraffin to the adhesive. As a result, the water repellency of the adhesive can be increased and the water resistance of the hologram can be improved. This hologram is
Since only one substrate is used, the hologram thickness can be reduced.

[0017]

In the present invention, since the side surface of the hologram is covered with the water repellent layer, it is not necessary to provide a seal width on the outer periphery of the hologram. Therefore, the diffraction grating film can be expanded to the side surface of the hologram, and a large area diffraction grating film can be formed. Therefore, the display area on the display can be expanded to the area of the hologram, and a larger display image can be reproduced and displayed.

Further, a water repellent layer is provided on the side surface of the hologram. Therefore, it is possible to prevent moisture in the surrounding environment from entering between the diffraction grating film and the cover plate and ensure sufficient water resistance. Further, the water repellent layer has higher water resistance and water repellency than the adhesive. Therefore, the water-repellent layer can be made much thinner than the seal width required for the adhesive.

Further, the hologram is formed with a water-repellent layer on the side surface of the hologram regardless of how many substrates and cover plates are used. Therefore, moisture does not enter between each substrate or the cover plate. Therefore, the hologram can be used for a long period of time. Further, according to the present invention, excellent water resistance can be exhibited by performing a simple process of providing a water repellent layer on the side surface of the hologram. According to the present invention, it is possible to provide a hologram having a large diffraction grating film and excellent water resistance.

[0020]

【Example】

Example 1 A hologram according to the present invention will be described with reference to FIGS. As shown in FIG. 1, the hologram 17 of this example includes a diffraction grating film 21 in which interference fringes are recorded and a diffraction grating film 2
1 and a glass substrate 22 disposed on one side.
Cover plates 51 and 53 are provided on the surface of the diffraction grating film 21 via an adhesive 6.

The water repellent layer 1 is provided on the side surface portion 15 of the hologram 17. The water repellent layer 1 has a low water permeability or a property of repelling water. The water-repellent layer 1 has a thickness of 0.
A wax is impregnated into a phenol resin having a thickness of 5 to 1 mm.

The cover plates 51 and 53 and the glass substrate 2
An epoxy thermosetting resin is used as the adhesive 6 that bonds the two. The refractive index of the adhesive 6 is 1.55. The diffraction grating film 21 is a dichromate gelatin film on which interference fringes are recorded and has a film thickness of 10 μm to 40 μm.
The glass substrate 22 is a transparent soda glass,
The size is 2 mm × 46 mm × 1.8 mm. The refractive index is 1.52.

The cover plates 51 and 53 are made of transparent soda glass and have a size of 112 mm × 46 mm × 1.0 mm.
Is the size of. The refractive index is 1.52. On the surface of the cover plate 51 on the atmosphere side, an antireflection film 52 formed by alternately stacking MgF ₂ and TiO ₂ is formed.
Further, on the surface of the cover plate 53 on the atmosphere side, a scattering prevention film 54 formed by mixing a black pigment with an epoxy resin is formed. The adhesive 6 is made of an epoxy resin thermosetting resin (manufactured by Cemedine Co., product CS-2340-5) and has a refractive index of 1.55. The thickness of the adhesive 6 is 5 each
It is 0 μm.

The hologram 17 is for diffracting and reflecting the light 30 incident from the antireflection film 52 side so that the viewer can visually recognize the display image displayed by the diffracted light 31.

Next, a method of manufacturing the hologram 17 will be described. First, 0.6 g of ammonium dichromate is dissolved in 100 ml of a 4% gelatin solution to prepare a dichromate gelatin solution as a photosensitizer. The refractive index of the dichromated gelatin solution is 1.55. Then, the above dichromate gelatin solution is applied to the surface of the glass substrate to form a film having a thickness of 1
0 to 40 μm, and after gelling or drying, 20
Stabilize by leaving it in an atmosphere of about 50% RH for 72 hours. As a result, a photosensitive film made of gelatin is formed on the surface of the glass substrate.

Then, as shown in FIG.
The glass substrate 22 on which 10 is formed has a focal length of 1000
A refractive index adjusting liquid 75 is sandwiched between a convex lens 76 having a size of mm and a prism 77. Silicon oil was used as the refractive index adjusting liquid 75.

Then, as shown in FIG.
An argon laser of 5 nm is swung so that the reproduction light (when the incident angle is 33.5) has two colors of 540 nm and 600 nm, and a total laser power of 500 mJ is incident as incident light 70 from the prism 77 side. . Incident light 7
Since 0 has a uniform refractive index after incidence, the convex lens 76
, And is reflected by the reflection film 761 formed on the surface of the convex lens 76 on the atmosphere side. This reflected light 7
1 passes through the photosensitive film 210 again. At this time, since the incident light 70 and the reflected light 71 interfere with each other on the photosensitive film 210, interference fringes are recorded on the photosensitive film 210.

A part of the reflected light 71 is not reflected by the glass substrate 22, and the refractive index adjusting liquid 75 and the glass substrate 22 are not reflected.
And then enters the prism 77 and is partially reflected by the incident surface of the prism 77. In this case, as shown in Figure 4,
The angle α of the incident surface of the prism 77 is adjusted with respect to the incident light 70, and the reflected light 71 of the incident surface of the prism 77 is changed to the photosensitive film 21.
It is better not to proceed in the direction of 0. In this example, the incident angle α was 30 °. In this way, the prism 7
By arranging 7, it is possible to remove display noise due to reflected light from the interface that causes noise.

It should be noted that by applying a black coating that absorbs light to the side surface of the prism 77, it is possible to prevent the reflected light from the incident surface of the prism 77 from advancing toward the photosensitive film 210. As a result, interference fringes are recorded on the photosensitive film 210.

After the exposure, the glass substrate 22 was washed with water until the color disappeared, and immersed in a commercially available photographic hardening fixer (Rapid Fixer manufactured by Kodak Co., Ltd.) for 10 minutes. 90% after washing
Then, it was immersed in a 100% isopropyl alcohol solution for 10 minutes and dried with hot air. Next, heat aging was performed at 150 ° C. for 4 hours so that the wavelength did not change under the usage environment.
As a result, the diffraction grating film 21 having interference fringes recorded is formed on one surface of the glass substrate 22.

Next, as shown in FIG. 5, a cover plate (11) having a 10 μm thick anti-scattering film 54 formed on the surface thereof is used.
2 mm × 46 mm × 1.0 mm) is prepared. The anti-scattering film 54 is made by adding 5% of a black pigment to an epoxy resin and mixing them (Cashew glass light 500). on the other hand,
Cover plate 51 having antireflection film 52 formed on the surface
(112 mm x 46 mm x 1.0 mm) is prepared. The antireflection film 52 has a structure in which four layers of MgF ₂ and TiO ₂ are alternately laminated, and the luminous reflectance is 0.3%.

The luminous reflectance was calculated by the following formula.

[Equation 1]

In the above equation, Y% is the luminous reflectance, λ is the wavelength of light (10 nm step), S (λ) = 1 (flat light source), R (λ) is the spectral reflection spectrum, and y (λ) is 1
931C1E color matching fun
Indicates the action. With a head-up display configuration (see FIG. 11), the noise image luminance was measured when the normal image luminance was 3000 cd / m ² (display distance was 1.9 m), and the noise rate (see below) was obtained. The hologram characteristics at this time were as shown in FIG. Noise rate = noise image brightness × 100 / normal image brightness (%)

Next, the adhesive 6 is applied to the surfaces of the cover plates 51 and 53 to a thickness of 50 μm. Next, the cover plates 51 and 53 are arranged on the glass substrate 22 as shown in FIG.
The glass substrate 22 was sandwiched by the adhesive 6 to obtain the hologram shown in FIG.

Thereafter, the side wall portion 15 of the hologram is coated with a phenol resin as the water repellent layer 1 to a thickness of 0.5 to 1 mm and impregnated with wax as an impregnating agent at 100 to 140 ° C. for 10 to 60 minutes. Let Thereby, the hologram 17 having the water repellent layer 1 having high water repellency is obtained.

Next, the function and effect of this example will be described.
The hologram 17 of this example has 65 ° C. and 95% RH even though no seal width is provided on the outer periphery of the hologram.
Under the above-mentioned use conditions, the reproduction wavelength hardly changed for 1000 hours, and sufficient reliability in use could be obtained. In addition, as shown in FIGS. 1 and 2, the diffraction grating film 21
Moisture of the surrounding environment did not enter between the cover plate 51 and the cover plate 53, and sufficient water resistance could be secured.

Further, since the water repellent layer 1 is provided on the side surface portion 15 of the hologram 17, the diffraction grating film 21 is attached to the hologram 1.
7 can be enlarged to the side surface portion 15 and a large area diffraction grating film 21 can be formed. Therefore, a larger display image can be reproduced and displayed.

The water-repellent layer 1 has higher water resistance and water repellency than the adhesive 6. Therefore, the water-repellent layer 1 can have a thickness much smaller than the seal width required for the adhesive 6. Also, by performing a simple process of providing the water repellent layer 1 on the side surface 15 of the hologram 17, excellent water resistance can be exhibited.

In this example, the antireflection film 52 is previously formed.
And the cover plate 51 on which the anti-scattering film 54 is formed,
Although 53 is used, the antireflection film 52 and / or the antiscattering film 54 may be attached after the glass substrate 22 having the diffraction grating film 21 is sealed or after the water repellent layer 1 is formed. . Further, in the hologram 17 of the present invention, noise was small during reproduction and recording, and the displayed image was clear.

Example 2 In this example, as shown in FIG. 7 and FIG.
A moisture-proof treatment agent is used as. The moisture-proofing agent cannot be expected to be as water-repellent as the phenol resin, but the seal width S of the outer peripheral portion 20 of the hologram is 3 mm larger than that of the conventional one.
It can be reduced to a certain degree. The moisture-proof treatment agent is used by attaching a liquid moisture-proof treatment agent to the side surface of the hologram and naturally drying. The thickness of the moisture-proofing agent is 10-500μ
m. Others are the same as in the first embodiment. Also in this example, the same effect as that of the first embodiment can be obtained.

Embodiment 3 In the hologram of this embodiment, as shown in FIG. 9, only the surface of the glass substrate 22 on the side of the diffraction grating film 21 is covered with the cover plate 53. An antireflection film 52 is formed on the surface of the glass substrate 22 on the atmosphere side. Also,
The anti-scattering film 5 is formed on the surface of the cover plate 53 on the atmosphere side.
4 are formed.

Others are the same as in the first embodiment. The hologram 17 of this example has a two-layer structure including one cover plate 53 and a glass substrate 22. for that reason,
The thickness of the hologram 17 can be reduced. Others are the same as in the first embodiment.

Example 4 In the hologram of this example, as shown in FIG. 10, a cover plate is not used and a one-layer structure of the glass substrate 22 is adopted. A diffraction grating film 21 recording interference fringes is formed on one side of the glass substrate 22. Diffraction grating film 21
The entire surface of is covered with the water repellent layer 11. On the other hand, an antireflection film 52 is formed on the surface of the glass substrate 22 opposite to the diffraction grating film 21.

The water-repellent layer 11 is formed by impregnating a phenol resin as an adhesive with a wax as an impregnating agent. As a result, the water repellency of the adhesive can be increased and the water resistance of the hologram can be improved. In addition, the water-repellent layer 11
For this purpose, it is preferable to mix with carbon black to make it black. As a result, the water-repellent layer 11 of this example can be provided with the same function as the anti-scattering film. The hologram 17 of this example uses only one substrate. Therefore, the thickness of the hologram 17 can be reduced. Other than that, the same effects as those of the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a hologram according to a first embodiment.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an explanatory diagram showing a method of recording interference fringes on the diffraction grating film of the first embodiment.

FIG. 4 is a graph showing the relationship between the reproduction wavelength and the diffraction efficiency of the hologram of Example 1.

FIG. 5 is an explanatory view showing the arrangement state of the glass substrate and the cover plate according to the first embodiment.

FIG. 6 is an explanatory diagram showing a laminated state of the glass substrate and the cover plate according to the first embodiment.

FIG. 7 is a cross-sectional view of the hologram according to the second embodiment.

8 is a sectional view taken along the line BB of FIG.

FIG. 9 is a sectional view of a hologram according to a third embodiment.

FIG. 10 is a sectional view of a hologram of Example 4.

FIG. 11 is a principle diagram of a head-up display device.

FIG. 12 is a sectional view of a conventional hologram.

13 is a sectional view taken along the line CC of FIG.

[Explanation of symbols]

 1, 10, 11. ． ． Water repellent layer, 15. ． ． Side surface, 17. ． ． Hologram, 21. ． ． Diffraction grating film, 22. ． ． Glass substrate, 51, 53. ． ． Cover plate, 52. ． ． Antireflection film, 54. ． ． Anti-scattering film, 6. ． ． Adhesive, S.I. ． ． Seal width,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Mizutani 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihondenso Co., Ltd.

Claims (5)

[Claims] 1. A cover plate having a diffraction grating film on which interference fringes are recorded and a substrate provided on one side of the diffraction grating film, and a cover plate provided on the surface of the diffraction grating film with an adhesive agent. A hologram comprising a water-repellent layer on a side surface of the hologram. 2. A hologram comprising a diffraction grating film having interference fringes recorded thereon, a substrate provided on one side of the diffraction grating film, and a water repellent layer covering the surface of the diffraction grating film. . 3. The water repellent layer according to claim 1, wherein the water repellent layer is an epoxy resin, a phenol resin, a butyral resin,
A hologram characterized by being one or more resins selected from the group consisting of acrylic resin, silicone resin, urethane resin, and fluororesin. 4. The hologram according to claim 1, wherein the water-repellent layer is a moisture-proofing agent such as modified acrylic, polyolefin, butyl modified rubber, vinyl, or fluoroacrylate. 5. The hologram according to claim 1, wherein the water repellent layer is impregnated with an impregnating agent such as wax or paraffin.