JP2000066014A - Diffraction grating recording body and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for featuring a shape of a diffraction grating cell, and manufacturing a diffraction grating recording medium with a counterfeit prevention effect and high decorativeness by masking a laser beam and converging it through a lens in a manufacturing method of the diffraction grating recording body for forming a pattern by an aggregation of fine diffraction gratings. SOLUTION: A laser beam emitted from a laser light source is split into parallel plane light B1, B2 and they are made incident on an image-forming system object surface PM at a predetermined angle to be interfered with each other. A mask for deciding a pattern form of the laser beam on this image- forming system object surface PM is arranged, a lens is arranged behind this mask and further, a photo-sensitive plate PP is arranged on an image-forming system image-forming plane PI which is an image-forming position through the lens of the mask. Then, a diffraction grating recording body is manufactured by photographing interference fringes where the pattern form is decided, and duplicating the image of the interference fringes patterned and photographed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffraction grating recording medium formed by arranging a minute diffraction grating using a laser beam and a method of manufacturing the same, and more particularly, to a diffraction grating by changing the pattern shape of the beam. The present invention relates to a diffraction grating recording body formed by changing the pattern shape of a grating and a method of manufacturing the same.

[0002]

2. Description of the Related Art A display having a diffraction grating pattern by two-beam interference and an apparatus for manufacturing the same are disclosed in JP-A-60-15 / 1985.
No. 6004. This prior art method exposes a fine interference fringe due to two-beam interference to a photosensitive film while changing its pitch, direction, and intensity,
It is to be a document of a diffraction grating recording medium.

[0003] Further, the laser light is interleaved as an expanded parallel light, and is masked by a mask arranged immediately before the photosensitive plate.
By transmitting only the corresponding part and causing interference,
Japanese Patent Application Laid-Open No. 3-164789 discloses a method for producing a display having a diffraction grating pattern characterized by forming a pattern having an arbitrary size and an arbitrary shape.

The pattern of the diffraction grating recording medium disclosed in Japanese Patent Application Laid-Open No. 60-156004 is formed by directly interfering two beams, and the pattern shape is the same as the beam shape of the laser light source. Are identical. Since the beam shape of a laser light source is generally circular and its distribution is not uniform, the shape of the diffraction grating pattern is only circular and the depth of the diffraction grating is not uniform. Therefore, there are problems such as a conspicuous pattern and a loss in the diffracted light rate.
In the method disclosed in JP-A-3-164789, the mask is placed immediately before the photosensitive plate, so that the photosensitive plate may be damaged. Further, since a gap is formed between the photosensitive plate and the mask, there is a problem that the profile of the diffraction grating is blurred due to diffraction at the edge of the mask.

On the other hand, a diffraction grating recording medium constituted by a diffraction grating pattern has been widely used for forgery prevention and decoration. For this reason, a technique for forming a pattern of a diffraction grating has become general, and differentiation has become difficult, and the effect of preventing forgery has been reduced.

[0006]

Therefore, in the present invention, a laser beam is masked and condensed by a lens, so that the shape of the diffraction grating pattern is characterized, and the anti-counterfeiting effect and its decorativeness are improved. It is an object to provide a diffraction grating recording body and a method for manufacturing the same.

[0007]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the invention of claim 1 provides a method of manufacturing a diffraction grating recording body for forming a pattern by a collection of minute diffraction gratings. The laser beam emitted from the laser light source is divided into B1 and B2, and the image plane PM
And a mask for determining the pattern shape of the laser beam is arranged on the image plane PM of the imaging system, an imaging lens is arranged on the back of the mask, and an image is formed as an imaging position by the lens of the mask. A method of manufacturing a diffraction grating recording body, characterized in that a photosensitive plate PP is arranged on a system imaging plane PI and an interference fringe of an arbitrary shape is imaged to manufacture the diffraction grating recording body.

According to a second aspect of the present invention, in the method for manufacturing a diffraction grating recording body, an element capable of electrically spatially modulating light is used for the mask.
The method for producing a diffraction grating recording medium described in (1).

According to a third aspect of the present invention, in the method for manufacturing a diffraction grating recording body, a liquid crystal display device is used for the mask. This is a method of manufacturing.

According to a fourth aspect of the present invention, there is provided a diffraction grating recording medium for forming a pattern by a group of minute diffraction gratings, wherein a laser beam emitted from a laser light source is divided into B1 and B2 to form an imaging system. A mask for determining the laser beam pattern shape is arranged on the object plane PM after being incident on the object plane PM, an imaging lens is arranged on the back of the mask, and an image forming position by the lens of the mask is further provided. In a diffraction grating recording body obtained by arranging a photosensitive plate PP on a barrel imaging plane PI and imaging interference fringes of an arbitrary shape, an element capable of electrically spatially modulating light is provided on the mask. This is a diffraction grating recording body characterized in that it is used.

According to a fifth aspect of the present invention, there is provided the diffraction grating recording body according to the fourth aspect, wherein a liquid crystal display device is used for the mask in the diffraction grating recording body.

[0012]

According to the method of claim 1,
Since the image is formed by the lens, a diffraction grating recording medium having a reduced and fine diffraction grating pattern in the same shape as a mask having a small blur amount can be created. Further, since the mask and the photosensitive plate are arranged at a sufficient distance, a diffraction grating recording body can be prepared without damaging the photosensitive plate.

According to the second aspect of the present invention, by using an element capable of spatially modulating light electrically as the mask, the light transmitted through the mask is spatially modulated by an electric signal input to the element, and the input is performed. A diffraction grating having a pattern that changes with a signal can be created. By this method, the shape of light transmitted through the mask can be changed, and the shape of the diffraction grating can be changed at high speed.

According to a third aspect of the present invention, a liquid crystal display device is used as an element capable of electrically spatially modulating light on a mask.

According to a fourth aspect of the present invention, there is provided a diffraction grating recording medium, wherein an electric signal input to the element is obtained by using an element capable of electrically spatially modulating light for a mask by using the method according to the first aspect. Thus, the light transmitted through the mask is spatially modulated, and a diffraction grating recording body in which a pattern that changes with an input signal is created.

According to a fifth aspect of the present invention, there is provided a diffraction grating recording body according to the fourth aspect, wherein the mask is formed by using a liquid crystal display device as an element capable of electrically spatially modulating light on a mask. FIG.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A diffraction grating recording body and a method of manufacturing the same according to the present invention will be described in detail below based on embodiments. FIG. 1 shows the configuration. The laser beam emitted from the laser light source is split by ordinary means, and converted into light B1 and B2 using a lens or the like. This is incident on the image plane PM. A mask A1 for determining the shape of the laser beam is arranged on the image plane PM of the imaging system. The beam that has passed through the mask A1 is condensed by an imaging lens L1 disposed on the back surface, and is imaged on an imaging system imaging plane PI that is an imaging position. The photosensitive plate PP is arranged on the imaging system imaging plane PI, and the interference fringes R having the pattern shape determined by the mask A1 are imaged. Thereafter, the photosensitive plate PP is developed by an ordinary method, and the interference fringes are reproduced as an original plate to manufacture a diffraction grating recording medium. In this method, as shown in FIG. 2, the laser beam is such that the light diffracted by the edge of the mask A1 is condensed by the lens L1 and the amount of blur at the mask edge is small, and the beam having the same shape as the mask A1 is formed on the photosensitive plate PP. Image.

As a lens used here, a group lens in which a plurality of lenses are combined or an aspheric lens can be used to further improve the blur of a mask to form an image. As an assembled lens to be used, an achromatic lens, a triplet, a lens incorporating an aspherical lens, or the like can be used. In the case of a single lens, aberration can be reduced by using a curved surface other than a spherical surface as the lens surface. Further, by using a plurality of these lens groups, it is possible to form an image of the mask with a reduction of about 1/10 to 1/100. An image can be formed by a system using a 4f system.

The mask can be obtained by etching a material obtained by printing a pattern on a silver salt dry plate or a material obtained by depositing a metal on a substrate. Further, the mask is not limited to the transmission type, but may be a reflection type. That is, the same effect can be obtained by changing the shape or intensity distribution of the laser beam depending on the difference in reflectance.

Further, an element capable of spatially modulating light by an electric signal can be used as the mask. As the reflective mask, a micromirror array in which minute mirrors are arranged in a matrix, a reflective liquid crystal panel, or the like can be used. An ordinary liquid crystal display device or the like can be used as the transmission type mask. FIG. 3 is an explanatory diagram showing an example of a case where a pattern PA is formed by inputting an electric signal EA and an example of a case where a pattern PB is formed by inputting an electric signal EB. Note that the element that can spatially modulate light by an electric signal is not limited to these elements, but may be any element that can control the light intensity distribution by an electric signal.

[0021]

According to the present invention as described above,
Two laser beams are transmitted through a mask, an image is formed on a photosensitive plate by a lens, and a diffraction grating recording body is formed in which a diffraction grating cell having a freely changed shape is arranged on a photosensitive material arranged on an imaging surface. be able to. In the present invention, since a mask forms an image on a photosensitive plate by a lens, a diffraction grating cell with less edge blur can be recorded. In addition, by using an element that can spatially modulate light with an electrical signal as a mask, it is possible to easily control the shape of the laser beam, and to record diffraction gratings composed of variously shaped diffraction grating cells. Can create a body. From the above, it is possible to provide a diffraction grating recording medium having a high anti-counterfeiting effect and high decorativeness and a method of manufacturing the same.

[Brief description of the drawings]

FIG. 1 is an explanatory view conceptually showing a manufacturing method of the present invention.

FIG. 2 is an explanatory view conceptually showing a manufacturing method of the present invention.

FIG. 3 is an explanatory view showing an electric light spatial modulation element.

[Explanation of symbols]

 L1: imaging lens A1: mask R: interference fringe of mask pattern shape B1, B2: plane light PM: imaging system object plane PI: imaging system imaging plane PP ... Photosensitive plate EA ... Electrical signal EB ... Electrical signal PA ... Mask pattern PB ... Mask pattern

Claims (5)

[Claims] In a method of manufacturing a diffraction grating recording body for forming a pattern by a group of minute diffraction gratings, a laser beam emitted from a laser light source is divided into B1 and B2.
Incident on the imaging system object plane PM, and
A mask for determining the pattern shape of the laser beam is placed on M, and an imaging lens is placed on the back of this mask,
Further, an imaging system imaging plane P which is an imaging position by the lens of the mask
1. A method for manufacturing a diffraction grating recording body, comprising: arranging a photosensitive plate PP on I; and imaging interference fringes of an arbitrary shape to manufacture the diffraction grating recording body. 2. The method of manufacturing a diffraction grating recording medium according to claim 2,
2. The method according to claim 1, wherein an element capable of electrically spatially modulating light is used for the mask. 3. The method of manufacturing a diffraction grating recording material according to claim 1,
3. The method according to claim 1, wherein a liquid crystal display device is used as the mask. 4. A diffraction grating recording body for forming a pattern by a collection of minute diffraction gratings, wherein a laser beam emitted from a laser light source is divided into B1 and B2 and incident on an imaging system object plane PM. A mask for determining the pattern shape of the laser beam is arranged on the imaging system object plane PM, an imaging lens is arranged on the back of the mask, and an imaging system imaging plane PI which is an imaging position of the mask lens is provided. In a diffraction grating recording body obtained by arranging a photosensitive plate PP on an image and imaging interference fringes of an arbitrary shape, an element capable of electrically spatially modulating light is used for the mask. Record body. 5. The diffraction grating recording body according to claim 4, wherein in the diffraction grating recording body, a liquid crystal display device is used for the mask.