JPH0364785A - Reproduction of lippmann hologram - Google Patents

Abstract

PURPOSE:To improve a mass production speed and to simplify mechanism by pressing the photosensitive material surface of a substrate to a Lippmann hologram in tight contact therewith and exposing the photosensitive material surface with a laser beam from the opposite side thereof while rotating a drum simultaneously with feeding of the substrate. CONSTITUTION:The drum 17 stuck with the Lippmann hologram around the same is disposed between a feed roll 14 and a take-up roll 15. The photosensitive material surface of the substrate 13 is pressed to the Lippmann hologram 16 by means of plural pieces of pressing rolls 18, 19 in tight contact therewith. The part to be exposed with the laser beam moves successively when the drum 17 rotates and the substrate 13 is fed. The Lippmann hologram 16 and the photosensitive material which are in tight contact with each other are then scanned by the linear light and the Lippmann hologram 16 is copied on the substrate 13. The recopying and the substrate movement are simultaneously executed in this way and the mass production is executed while the substrate 13 is continuously run. The mass production speed is improved and the mechanism is simplified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for replicating a Lippmann hologram, and particularly to a method for replicating a Lippmann hologram that improves mass production speed and simplifies the device configuration. It is about the method.

[Prior Art] In recent years, in the publishing and printing industry, there are many products such as book and magazine covers, illustrations, gifts, novelties, securities, etc.
Holograms have been widely used as a means to prevent counterfeiting of credit cards and IC cards. There are various types of holograms of this type, one of which is the Lippmann hologram. In other words, hologram recording is carried out by interfering a light called an object beam with a light called a reference beam, but these two beams are recorded by entering them from different sides, such as the front and back of a photosensitive material. Hologram, Lippmann
It's called a hologram.

This Lippmann hologram is a reflection type hologram that allows the image to be observed from the same side as the direction in which the reproduction light is incident.Unlike other holograms, the hologram itself has wavelength selectivity, so it uses laser light. It also has the characteristic that a good reproduced image can be obtained even when reproduced using white light. For this reason, it is widely used as a white light reproduction type display hologram.

By the way, as a method for duplicating this type of Lippmann♦ hologram, a method called a contact copying method is usually employed. In this method, as shown in Fig. 2, a photosensitive material (dry plate) 2 is placed in close contact with a normally photographed Lippmann hologram (referred to as a copy master when copying) 1, and then a laser 3 is applied to the mirror. 4. By applying uniform laser light through the lens 5,
This is a method of replicating Lippmann holograms. That is, in principle, as shown in FIG. 3, after the laser beam passes through the photosensitive material 2, the lower Lippmann hologram (
Since the image is reproduced by being diffracted by the copy master) 1, the light a passing through the photosensitive material 2 acts as a reference light,
The light that reproduces the image on the Lippmann hologram 1 after passing through the photosensitive material 2 acts as object light, and a Lippmann hologram l is recorded on the photosensitive material 2.

This method has the advantage of being less affected by vibrations than normal photographing.

On the other hand, recently, a method called scanning has come to be used when photosensitive materials and Lippmann holograms are irradiated with laser light in the contact copy method. This method exposes the entire surface of the photosensitive material by spreading the laser beam linearly with a cylindrical lens and scanning the linear beam. However, it has advantages in that the exposure time per unit time is short and the light utilization efficiency is high.

FIG. 4 is a schematic diagram showing an example of the overall configuration of an apparatus for duplicating a Lippmann hologram using such a contact copy method. That is, as shown in FIG. 4, a sheet-like substrate 7 whose surface is coated with a photosensitive material is first fed by a certain amount from the feed roll 6, and then a Lippmann hologram (copy master) 8 and the photosensitive material of the substrate 7 are fed. A Lippmann film is applied onto the substrate 7 by exposing the substrate 7 to a laser beam from the laser 9 through the mirror 10 and the lens 11 from the side opposite to the photosensitive material.
A hologram is recorded and then wound up with a winding roll 12. In this case, exposure methods for contact copying include a uniform exposure method using a high-output laser and a scanning method.

[Problems to be Solved by the Invention] However, the conventional method for duplicating the Nori-Tubman Society hologram as described above has the following problems. That is, since it is necessary to feed the substrate 7 by a certain amount and stop the movement of the substrate 7 during exposure, mass production cannot be carried out while continuously feeding the substrate 7. For this reason, there is a problem that not only is it difficult to increase the mass production speed, but also that the mechanism such as the feed roll 6 becomes complicated.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for replicating a Lippmann hologram that can easily increase mass production speed and simplify the device configuration. purpose.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a sheet-like substrate whose surface is coated with a photosensitive material and is fed from a feed roll, and is wound up with a take-up roll. A drum with a Lippmann hologram affixed to its periphery is placed between a feed roll and a take-up roll, the photosensitive material surface of the substrate is pressed against the Lippmann hologram by multiple pressure rolls to bring it into close contact, and the substrate is sent. At the same time, the Lippmann hologram is copied onto the substrate by exposing the substrate to laser light from the anti-photosensitive material side while the drum is rotating.

[Function] Therefore, in the present invention, when the drum rotates, the Lippmann
As the hologram and substrate move together with the drum, the substrate is fed and the parts of the Lippmann hologram and substrate that are exposed to laser light are moved, resulting in contact copying by scanning. In the same way as when performing , the Lippmann hologram and the photosensitive material that are in close contact with each other are scanned with linear light, so the Lippmann hologram is copied onto the substrate. This results in
Since copying and substrate movement are performed at the same time, mass production can be carried out while the substrates are being fed continuously, making it possible to easily increase mass production speed and simplify mechanisms such as feed rolls.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of the overall configuration of an apparatus for realizing the Lippmann hologram duplication method according to the present invention. In FIG. 1, a sheet-like substrate 13 whose surface is coated with a photosensitive material is supplied from a feed roll 14, and this substrate 13 is wound up by a take-up roll 15. Further, between the feed roll 14 and the take-up roll 15, there is disposed a drum 17 around which a Lippmann hologram 16 is affixed as shown. Further, two pressure rolls 18 and 19 are disposed near the drum 17 as shown in the figure, so that the surface of the photosensitive material of the substrate 13 is pressed against the Lippmann hologram 16 to bring it into close contact. Furthermore, the laser 20, the mirror 21, and the cylindrical lens 2
2, the substrate 13 is irradiated (exposed) with a laser beam that spreads linearly in a direction parallel to the axis of the drum 17 from the side opposite to the photosensitive material.

Next, a method of replicating a Lippmann hologram according to this embodiment will be explained.

In FIG. 1, as the drum 17 rotates, the hologram 16 and the substrate 13 move together with the drum 17 during its ascent. As a result, the board 13 is sent, and
The Lippmann e-hologram 16 and the portion of the substrate 13 that is exposed to the laser beam will move, and as a result, the Lippmann hologram 16 that is in close contact will move, similar to when contact copying was performed by scanning as described above. Since the photosensitive material is scanned with linear light, the substrate 13
The Lippmann hologram 16 is copied on top. In this case, since the copying and the movement of the substrate 13 are performed simultaneously, there is no need to stop the substrate 13 as in the conventional case, and mass production can be performed while the substrate 13 is continuously flowing.

Therefore, the mass production speed can be easily increased, and the mechanism such as the feed roll 14 can be simplified.

As described above, in this embodiment, a sheet-like substrate 13 whose surface is coated with a photosensitive material and is fed from a feed roll 14 is used.
is wound up by a take-up roll 15, and a drum 17 on which a Lippman◆ hologram 16 is pasted is disposed between the feed roll 14 and the take-up roll 15, and the photosensitive material surface of the substrate 13 is taken up by a Lippman hologram 16.・Press the hologram 16 with two pressure rolls 18 and 19 to bring it into close contact, and expose the substrate 13 with laser light from the anti-photosensitive material side while rotating the drum 17 at the same time as sending the substrate 13. Accordingly, the Lippmann hologram 16 is copied onto the substrate 13.

Therefore, since copying and movement of the substrate 13 can be performed simultaneously, there is no need to compare the substrates 13 each time during exposure as in the conventional method, and mass production can be performed while continuously feeding the substrates 13. This makes it possible to easily increase the mass production speed and to significantly simplify the mechanism such as the feed roll 14.

[Effects of the Invention] As explained above, according to the present invention, a sheet-like substrate whose surface is coated with a photosensitive material and supplied from a feed roll is wound up with a take-up roll, and a Lippmann ◆
A drum with a hologram pasted on it is placed between a feed roll and a take-up roll, and the photosensitive material surface of the substrate is pressed against the Lippmann hologram by multiple pressure rolls to bring it into close contact with the drum. Since the substrate is exposed to laser light from the anti-photosensitive material side while the substrate is being rotated, mass production speed can be easily increased and the equipment configuration can be simplified. Replication methods can be provided.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a device for realizing the Lippmann hologram duplication method according to the present invention;
Figure 2 is a schematic diagram for explaining the contact copy method.
Figure 3 is a diagram to explain the principle of contact copy.
FIG. 4 is a schematic diagram showing an example of an apparatus configuration for realizing the conventional Lippmann hologram duplication method. 13... Substrate, 14... Feeding roll, 15... Winding roll, 16... Lippmann hologram, 17...
...Drum, 18.19...Press roll, 20...
Laser 21... Mirror 22... Cylindrical lens.

Claims (1)

[Claims] A sheet-like substrate whose surface is coated with a photosensitive material and supplied from a feed roll is wound up by a take-up roll, and a drum with a Lippmann hologram affixed to its periphery is placed between the feed roll and the take-up roll. The surface of the photosensitive material of the substrate is pressed against the Lippmann hologram by a plurality of pressing rolls, and the drum is rotated at the same time as the substrate is fed, and the surface of the substrate is pressed against the surface of the Lippmann hologram. A method for copying a Lippmann hologram, characterized in that the Lippmann hologram is copied onto a substrate by exposing it to laser light from the side of the optical material.