JP3344590B2 - Anti-fog hologram - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-fogging hologram, and more particularly to a hologram disc which has been subjected to anti-fogging treatment.

[0002]

2. Description of the Related Art In recent years, POS (point-of-sale information) systems have attracted attention, and the demand for barcode readers has been growing rapidly. A bar code reader is a machine that reads a code (bar code) written on a product, and it is necessary to scan a laser beam when reading this code. Laser beam scanning method 1
For example, a method using a holographic zone plate (hereinafter, referred to as a hologram disk) is known. Recently, attempts have been made to apply the optical scanning technology using a hologram disc to optical scanning of a laser beam printer which requires higher optical scanning properties (beam convergence, linear scanning properties, etc.) than a barcode scanner. I have.

[0003]

However, in the above prior art, the area around the hologram disk is about 80%.
When the humidity becomes high as described above, water droplets adhere to the surface of the hologram disk and irregularly reflect the incident laser light, so that there is a problem that the scanability of the laser light is significantly reduced.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a hologram having anti-fogging properties exhibiting good characteristics even at high humidity, as well as at normal humidity, in particular, An object of the present invention is to provide a hologram disk having anti-fog properties.

[0005]

As a result of various studies to solve the above problems, as a result of providing a plastic layer having antifogging properties on at least one surface of a hologram disk for scanning a laser beam, the laser beam has a high scanning performance. The inventors have found that the above problems can be solved by preventing the dew condensation on the disk surface which causes the deterioration, and completed the present invention.

That is, the present invention prevents dew condensation on the disk surface even when the disk is left under high humidity.
The present invention relates to an anti-fog hologram disk capable of maintaining good laser light scanning properties.

Hereinafter, the anti-fogging hologram of the present invention will be further described with reference to the drawings. First, in the present invention, a hologram disk is provided with a hologram layer 1 for scanning with a laser beam, a support base material layer 2, and a hologram layer 1 as shown in FIGS. 1 (a) and 1 (b). It is composed of a hydrophilic plastic layer 3 provided on one side or both sides.

In the above, the supporting substrate 2 that can be used has a thickness of 0.01 to 100 mm, preferably 1 to 5 mm.
mm glass substrate, acrylic substrate, polycarbonate substrate, polyethylene substrate, polypropylene substrate, polyethylene terephthalate substrate, polystyrene substrate and the like. Among them, particularly preferred are a glass substrate, an acrylic substrate, and a polycarbonate substrate, which are substrates having sufficient mechanical strength, low birefringence, and high transparency. As the hologram material 1, any photosensitive material for hologram applications can be applied to the present invention, but a commercially available silver salt photosensitive material or a photopolymer photosensitive material is used because of good availability and workability. Is preferred. As the hydrophilic plastic layer 3, if a resin having sufficient hydrophilicity so as not to form water droplets is used in the form of a film as it is, after coating, a coating film is formed by drying or irradiation with ionizing radiation. Any of the cases can be applied to the present invention. Examples of the film shape include a polyvinyl alcohol film, a polyethylene glycol film, a polyhydroxyethyl (meth) acrylate film, a triacetylcellulose film, a saponified surface film of triacetylcellulose, and the like. A triacetylcellulose surface saponified film having coating strength is preferred. After application, the resin that forms a coating film by drying is polyvinyl alcohol, polyvinyl formal, polyethylene glycol, polyhydroxyethyl (meth) acrylate,
Polyvinylpyrrolidone, triacetyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and the like can be mentioned. After application, as a resin that forms a coating film by irradiating ionizing radiation, as long as it is an ultraviolet ray and electron beam curable hydrophilic resin ink, it is applicable to the present invention, but availability and workability are good. For this reason, it is preferable to use a commercially available ionizing radiation-curable ink for anti-fog use. Particularly preferred as these hydrophilic plastic layers are those obtained from ionizing radiation-curable inks that are easily controllable in film thickness, have sufficient mechanical strength when containing water, have low birefringence, and have high transparency. It is a coating layer.

Means for obtaining the above-mentioned layer structure include a method of providing an anti-fog layer after recording a hologram and a method of recording a hologram after providing an anti-fog layer in advance. Good.

[0010] Typically, in the case of a reflection type hologram, as shown in FIG. 2A, a parallel light 5 and a divergent light 6 are applied to the photosensitive plate 4 from opposite sides. Te 2
In the case of the transmissive type, as shown in FIG. 2 (b), parallel light 5 and divergent light 6 are applied from the same side of the photosensitive plate 4 to cause interference between the two light beams. Regarding the hologram recording method, a volume type is preferable in both the reflection type and the transmission type in order to obtain smoothness of the disk surface.

That is, the anti-fogging hologram of the present invention comprises:
In a hologram comprising a hologram layer on which a hologram interference pattern is recorded and a support substrate, a triacetyl cellulose surface saponified film or an ionizing radiation-curable ink is provided on both the exposed surface of the hologram layer and the opposite surface of the support substrate. And a hydrophilic plastic layer comprising:

The anti-fogging hologram of the present invention is preferably configured as a hologram disk for scanning a laser beam.

[0013]

In the present invention, since the hydrophilic plastic layer is provided on both surfaces, dew condensation on the hologram surface can be prevented.
Even under high humidity, good laser light scanning properties can be maintained as in the case of normal humidity. And, since the hydrophilic plastic layer is made of a triacetylcellulose surface saponified film or an ionizing radiation-curable ink, even if it absorbs high-humidity moisture and contains water, it has a relatively high coating film strength, so that mechanical strength, It will be excellent in durability.

[0014]

EXAMPLES Some examples of the anti-fogging hologram of the present invention and comparative examples will be described below. In the following, the scanability of the hologram disc under high humidity is as shown in FIG. 3A in the case of the reflection type in an environment test chamber set at a predetermined temperature and humidity. An evaluation system was used, and in the case of the transmission type, the evaluation was performed using an evaluation system as shown in FIG. 3A and 3B, a hologram disk 7 was irradiated with a laser beam from a He-Ne laser or a semiconductor laser 8, and the diffraction efficiency and beam convergence of the diffracted light were evaluated. Here, the diffraction efficiency is the intensity ratio of the diffracted light to the incident light, and the beam convergence is evaluated from the average value of the beam diameter at the beam waist by using a beam scan (manufactured by Photon Corporation). .

EXAMPLE 1 Photopolymer photosensitive material for hologram recording (Omnidex 352: manufactured by DuPont) on a glass substrate (manufactured by Suzuki Glasstech) having a thickness of 3.0 mm by spin coating.
And dried to form a coating film having a thickness of 25 μm.
A 27 μm surface-saponified triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd.) was laminated. This was irradiated with an Ar laser having a wavelength of 514 nm and caused to interfere, thereby producing a reflection-type hologram disk.

The beam convergence and diffraction efficiency of the obtained hologram disk under high humidity (temperature 25 ° C., relative humidity 95%) of He—Ne laser light (wavelength 633 nm) were measured. The beam diameter was 450 μm. The diffraction efficiency was 90%. This means that the beam diameter under normal humidity (temperature 25 ° C., relative humidity 40%) (beam diameter 45
0 μm, diffraction efficiency 92%).

Example 2 A photopolymer photosensitive material for hologram recording (Omnidex 352: Acrylite: manufactured by Mitsubishi Rayon Co., Ltd.) was applied on a 3.0 mm-thick acrylic substrate (Acrylite: manufactured by Mitsubishi Rayon Co., Ltd.).
(DuPont) was applied and dried to form a coating film having a thickness of 25 μm, and an acrylic film (Acryprene: manufactured by Mitsubishi Rayon Co., Ltd.) having a thickness of 50 μm was laminated. This was irradiated with an Ar laser having a wavelength of 514 nm and caused to interfere, thereby producing a reflection-type hologram disk.

On the acrylic film surface of the hologram disk, a UV-curable hydrophilic resin paint (HARD) is used.
(IC RC-5016: manufactured by Dainippon Ink Industries, Ltd.)
Was applied to a thickness of 10 μm using an applicator, dried at a temperature of 80 ° C., and irradiated with 100 mJ / cm ^{2 of} ultraviolet light using a high-pressure mercury lamp (manufactured by JEOL Ltd.).

The beam convergence and diffraction efficiency of the obtained hologram disk under high humidity (temperature 25 ° C., relative humidity 95%) of He—Ne laser light (wavelength: 633 nm) were measured, and the beam diameter was 500 μm. The diffraction efficiency was 80%. This means that under normal humidity (temperature 25 ° C., relative humidity 40%) (beam diameter 48
0 μm, diffraction efficiency 88%).

Example 3 Acrylic substrate having a thickness of 3.0 mm (manufactured by Nitto Jushi Co., Ltd.)
A film-shaped photopolymer photosensitive material for hologram recording (HRF-600: manufactured by DuPont) was laminated thereon using a rubber roller. This was irradiated with an Ar laser having a wavelength of 514 nm and caused to interfere, thereby producing a transmission type hologram disk.

Electron beam-curable hydrophilic resin paint (DAF-63: manufactured by The Inktec Co., Ltd.) was applied on both surfaces of this hologram disc by a bar coat, and a 25 μm specular PET film (Lumilar T-70) was applied. : Toray Industries, Inc.)
Was laminated using a laminator. Using an electron beam irradiation device (Nissin High Voltage Co., Ltd.),
Accelerating voltage 175 KeV, irradiation dose 5 Mrad. After irradiation with an electron beam under the conditions described above, the PET film of the laminate was peeled off to obtain an antifogging hologram disk.

The beam convergence and diffraction efficiency of the semiconductor laser beam (wavelength: 670 nm) of the obtained hologram disk under high humidity (temperature: 25 ° C., relative humidity: 95%) were measured. The efficiency was 85%. This is under normal humidity (temperature 25
℃, relative humidity 40%) (beam diameter 150μ)
m, diffraction efficiency 88%).

Comparative Example 1 The beam convergence and the diffraction efficiency of the hologram disk produced in the same manner as in Example 2 except that the hydrophilic plastic layer was not provided were examined.

The measurement of the hologram disk under high humidity (temperature: 25 ° C., relative humidity: 95%) using a He—Ne laser beam (wavelength: 633 nm) showed that the beam diameter was 10%.
At 00 μm, the diffraction efficiency was 20%. This was much different from that under normal humidity (temperature: 25 ° C., relative humidity: 40%) (beam diameter: 480 μm, diffraction efficiency: 88%).

Comparative Example 2 The beam convergence and the diffraction efficiency of the hologram disk manufactured in the same manner as in Example 3 except that the hydrophilic plastic layer was not provided were examined.

Measurements of this hologram disc under high humidity (temperature 25 ° C., relative humidity 95%) using semiconductor laser light (wavelength 670 nm) showed that the beam hardly converged due to irregular reflection. On the contrary,
Under normal humidity (temperature: 25 ° C., relative humidity: 40%), the diffraction efficiency converged to 88% and the beam diameter was 150 μm.

The reason why the hologram disk can maintain the same laser beam scanning performance as in the case of the above-described embodiments even under high humidity can be explained as follows. FIG. 4A schematically shows the operation of the conventional hologram disk without the hydrophilic plastic layer, and FIG. 4B schematically shows the operation of the hologram disk of the present invention with the hydrophilic plastic layer. On the other hand, in the conventional case, since the surface of the hologram disk is not subjected to hydrophilic processing, water droplets 9 are generated due to dew condensation. For this reason, the laser beam 10 is partially scattered by the water droplets 9, the diffraction efficiency is reduced, and the beam convergence is deteriorated. On the other hand, in the case of the present invention, since the surface of the hologram disk is subjected to the hydrophilic processing 3, water droplets on the disk surface which cause a decrease in laser beam scanability (reduction in transmittance, irregular reflection, etc.) do not occur, Good laser light scanning properties can be maintained even under high humidity.

The anti-fogging hologram of the present invention is not limited to a hologram disk, but can be applied to various holographic optical elements using laser light. Further, the present invention is also applicable to a use for preventing a deterioration in design of a hologram on which a picture is recorded.

[0029]

As is clear from the above description, according to the anti-fogging hologram of the present invention, since the hydrophilic plastic layer is provided on both surfaces, dew condensation on the hologram surface can be prevented. In the case of the configuration, even under a high humidity, good scanability of laser light can be maintained as in the case of a normal humidity. And, since the hydrophilic plastic layer is made of a triacetylcellulose surface saponified film or an ionizing radiation-curable ink, even if it absorbs high-humidity moisture and contains water, it has a relatively high coating film strength, so that mechanical strength, It will be excellent in durability.

As can be understood from a hologram disk for a bar code scanner, a hologram disk is generally arranged in a closed space where air circulation inside the machine body is poor. Therefore, it is difficult to remove dew condensation by wiping the disk surface. In addition, the inside of the machine body becomes relatively hot when the disk is used, so that more water vapor is sucked in from the outside.
It is cooled before next use, and at the beginning of use,
Especially in winter or the like, dew condensation easily occurs on the disk surface. Also in this respect, the anti-fogging hologram disk according to the present invention is remarkably excellent in workability as compared with the conventional one.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a form of an antifogging hologram according to the present invention.

FIG. 2 is a diagram for explaining an arrangement of a recording system of a reflection type and a transmission type hologram.

FIG. 3 is a diagram for explaining an arrangement for evaluating diffraction efficiency and beam convergence of a hologram disk.

FIG. 4 is a diagram schematically showing the operation of a conventional hologram disc and the hologram disc of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hologram layer 2 ... Support base material layer 3 ... Hydrophilic plastic layer 4 ... Photosensitive plate 5 ... Parallel light 6 ... Divergent light 7 ... Hologram disk 8 ... Laser 9 ... Water drop 10 ... Laser light

Claims (2)

(57) [Claims] 1. In a hologram comprising a hologram layer 1 on which a hologram interference pattern is recorded and a support substrate 2, triacetyl cellulose is provided on both the exposed surface of the hologram layer 1 and the opposite surface of the support substrate 2. Surface saponified film
Alternatively , an antifogging hologram provided with a hydrophilic plastic layer 3 made of an ionizing radiation curable ink . 2. The anti-fogging hologram according to claim 1, wherein the hologram disk is configured to scan with a laser beam.