JPS6023821A - Hologram disc - Google Patents

Abstract

PURPOSE:To obtain a hologram disc having high performance in high yield by removing either one of the parts of hologram layers facing each other then joining the hologram layers to each other in such a way that the parts facing each other are positioned in said removed parts. CONSTITUTION:A hologram disc 11 of which at least the facets 7 and 8 are non- defective is formed if, for example, the two facets 7 and 8 in a hologram disc 10 consisting of eight facets 1-8 are defective. The defective faces 7, 8 of the disc 10 and the facets except the 7 and 8 of the disc 11 are respectively removed and both discs 10, 11 are combined and joined in such a way that the respective hologram layers face each other and that the mutual remaining facets compensate the rough removed parts with each other. The joined hologram of which all the facets are defectless is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a bologram disk used in a bologram scanner.

(Background of BL Technology) Recently, hologram scanners using bolograms have become common as barcode reading devices in POS (Paint-of-3ale) systems or optical scanning mechanisms in laser printers and the like.

The hologram scanner is an optical scanning mechanism that utilizes the diffraction phenomenon caused by holograms, and usually rotates a disk (hologram disk) on which a hologram is formed, and uses a laser beam, etc., projected onto the hologram disk. Optical scanning is performed by changing the direction of the light beam as the hologram disk moves.

The hologram scanner has a simpler and more compact optical system than conventional optical scanning systems that use rotating mirrors or galvano mirrors, and high-speed optical scanning is relatively easy. It has the following characteristics.

(C) Prior Art and Problems The hologram disk used in the above-mentioned hologram scanner is generally disk-shaped, as shown in FIG. A hologram is formed in the layer of photosensitive material. The hologram generally has multiple parts (facets) as shown.
(1) Each time one of the facets 1 passes the position of the light beam 2 as the hologram disk rotates, the diffracted light 3 is deflected by an angle θ, for example, and as a result, the projection surface 4 is optically scanned.

An example of a method for forming a hologram on the hologram disk will be described with reference to FIG. 2. As shown in the figure, a mask 7 having an opening 6 of a predetermined shape is placed on a transparent disk 5 made of glass or the like, on which the photosensitive interest layer is formed, and
A hologram of one facet (
interference fringes) are formed. The disk 5 is rotated and similar exposure is performed to sequentially form bolograms at other facet positions. Thereafter, the bologram disk is completed by performing treatments such as bleaching and forming a surface protective layer.

It is desirable that the holograms of facets 1 to 1 have high light usage efficiency (ratio of first-order diffracted light energy to incident light energy) and that there is little difference in the light usage efficiency between the facets. However, due to poor exposure during bologram creation (predetermined interference fringes are not formed due to fluctuations in the exposure optical system, etc.) or poor processing (unevenness due to dirt, uneven processing, etc.), some facets
may cause defects. This lowered the yield of holograms and discs, causing high costs.

By the way, if the hologram disk is divided into 10 facets, and the probability that one non-defective facet force <1-7 after exposure and processing is p, then the probability P of a hologram disk is p -, p n, and in order to obtain P-90%, it is necessary that p#99%. This value is extremely difficult to achieve. Therefore, if you consider the cost, it is unavoidable to sacrifice some performance.

fd1 Purpose of the Invention The object of the present invention is to provide a high-performance hologram disk with a high yield by replacing the defective portion with a good hologram in a hologram disk in which a defective portion exists in a part. do.

(e1 Structure of the Invention The present invention consists of a hologram layer and a support, each hologram layer has the same hologram formed thereon, and corresponding portions of each hologram layer are mirror-symmetrical to each other. In two hologram disks supported by respective supports, one of the corresponding portions of the hologram layer is removed, and then the hologram layers are bonded to each other such that the corresponding portion is located in the removed portion. It is characterized by joining hologram disks in which each hologram layer is composed of a plurality of facet 1-porograms, and by using a hologram on one hologram disk to form a hologram on the other hologram disk.
This includes forming using two light beams having the same wavefront and opposite traveling directions as each of the two light beams.

(F1 Embodiments of the Invention Below, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same parts as in the previously shown drawings are designated by the same reference numerals.

The basics of the present invention are that, as shown in FIG. 3(A), if two facets of ■ and ■ are defective in the hologram disk 1o consisting of eight facets, As shown, a hologram disk 11 having at least the good facets ■ and ■ is prepared, and after removing the defective facets ■ and ■ of the hologram disk 10 and the facets other than ■ and ■ of the hologram disk 11, The Durham disks are combined and bonded so that their respective bologram layers face each other, and each residual facet compensates for the removed portion of the other [FIG. 4(C)].

FIG. 5(D) is a cross-sectional view of the hologram disk in a joined state.

In this case, the holograms formed on the hologram layers at facets 1 to ■ and ■ of the hologram disk 11 must be formed exactly the same as the holograms to be formed on the hologram layers at facets ■ and ■ of the hologram disk 10. A7゜That is, the holograms in the hologram layer of the hologram disk 11 are exactly the same as those in the hologram layer of the hologram disk 10, but the spatial positional relationship between the hologram layer and the transparent disk 5 is different from that of the hologram layer, for example. Assuming that the front and back sides are attached, the bologram disk 10 is in contact with the transparent disk 5 on the front side, while the bologram disk 11 is in contact with the transparent disk 5 on the front side.
Now, they will meet on the back side. As a result, the corresponding facets 1 of the porographic disk 10 and the volographic disk 11 are positioned in mirror symmetry with respect to each other.

An example of a method for forming holograms having the above-mentioned positional relationship on each of the hologram layers roughly formed on the two transparent disks 5 will be explained.

Corresponding positions between the two bologram layers as above,
For example, arranging each of the FPS I-1 in a mirror-like manner can be easily realized by reversing the direction of rotation of the transparent disk 5 in FIG. However, for each transparent disk 5, the interference light beams (light beams 8 and 9) shown in FIG.
If they are used equally, the three-dimensional structure of the interference fringes forming the holograms will be exactly the same between the corresponding facenos l-1. When two such boluses, grains, and disks are joined as shown in Figure 3, the hologram or facet used for compensation
is inconvenient because the compensated bologram is turned upside down.

In the present invention, when one hologram disk is created using the interference light shown in FIG. By using , the holograms in the corresponding parts of each hologram disk are arranged in a point-symmetrical spatial arrangement with the axis being a straight line perpendicular to the rotation axis of the hologram disk, that is, when one of the corresponding parts is compensated for by the other, The three-dimensional structures of the holograms to be formed in each case can be made to be exactly the same.

FIG. 4 shows an example of interference light used in the above.

The same figure (A) shows the formation of a hologram on the first hologram disk, in which one hologram layer on the transparent disk 5 has two light beams, for example, a plane wave 13, and a point P as the divergence center. A spherical wave 14 is projected,
Interference fringes (holograms) 15 and 1G are formed on the bisector of the traveling directions of the plane wave 13 and the spherical wave 14 due to the T crossing of these optical wavefronts.

On the other hand, as shown in FIG.
Two light beams, for example, a plane wave 17 and a spherical wave 18 converging at point Q, are projected onto 21, and interference fringes (holograms) 19 and 20 are formed in the same manner as described above.

In FIGS. 4(A) and 4(B), the plane wave 13, the plane wave 7, the spherical wave 14, and the spherical wave 1B have the same wavefront and one direction of propagation is opposite. . When the hologram layer 12 and the hologram layer 121 formed in this way are stacked facing each other, interference fringes (bolograms) 15 and 19 and interference fringes (hologram) 1 are formed.
6 and 20 each have exactly the same three-dimensional structure, and do they have the same three-dimensional structure? 11i reimbursable.

That is, if one of the bolograms or granograms has a defect, it can be removed and replaced with the other hologram.

FIG. 5 shows another embodiment in which a hologram capable of compensating for the hologram of a certain hologram disk is formed on another hologram disk.
The hologram N122 of the master) 21 and the hologram layer 1 of the hologram disk 22 on which a new hologram is formed
23 are stacked facing each other, and a light beam, for example, a plane wave 23, is projected onto this.

As a result, the diffracted light due to the bologram of the hologram disk 21 appears to be a spherical wave 24 whose divergence center is at the upper point R.
Therefore, interference fringes (hologram) of these lights are formed in the hologram layer 123 on the bisector of the rectilinear light of the plane wave 23 (light transmitted through the hologram layer 122) and the diffracted light. Hologram N12 formed in this way
It is possible to mutually compensate with the hologram of No. 3 hologram Bad (program N122), and also with the hologram of the certain hologram disk.

FIG. 6 shows an application example of the present invention. In the above, the purpose of hologram compensation between two hologram disks is to prevent the holograms of a certain hologram disk from partially having low first-use efficiency, or due to dirt, defects, etc. However, in this embodiment, the compensation function is used more actively.

That is, for example, in optical scanning for POS terminals, a normal laser beam is used, but in order to keep the intensity of the laser beam emitted from the device and scanned over the barcode within the L. It is desirable to set the light source output as low as possible using a holographic disk with uniform facet pre-use efficiency. On the other hand, for condensing the reflected light from the barcode, it is desirable that the condensing efficiency (equal to the previously used IJ rate) be as high as possible, and the above-mentioned uniformity is not strictly required.

Therefore, as shown in Fig. 6, the porogram on the bologram disk is used for scanning the emitted light, and the part (2) used is a hologram with uniform first use efficiency, while the part [phase] and (2) which mainly contribute to light collection are It is effective to form a hologram with high first use efficiency. In this case, it is extremely difficult to control the holograms on one hologram disk to have partially different first use efficiencies, but by using the method of the present invention, one hologram disk has different first use efficiencies. forms a hologram with relatively good uniformity, leaves only the shaped part like ■ in Figure 6, and removes the rest, and the other hologram disk forms a hologram with high first use efficiency. , by leaving only the shaped portions O and 0 in Figure 6 and removing the others, and joining each hologram disk in such a way that the hologram layers mutually compensate for each other, the desired hologram disk can be easily fabricated. can be gη. In this case, a 1-gram disk with good uniformity of first-use efficiency can be obtained by using a hologram layer with a relatively small thickness, whereas a 1-gram disk with a relatively thick hologram layer can be used to obtain an absolute value of first-use efficiency. It is sufficient to take advantage of the fact that a hologram disk with a large amount of hologram can be obtained.

(g) Effects of the Invention According to the present invention, in a bologram disk, a porogram with an uneven distribution of first use efficiency or a partially dirty or defective hologram can be replaced with a hologram of another point 1:+gram disk. By each replacement, it is possible to obtain a bologram disk with good uniformity, and it is also possible to intentionally change the distribution of the first use efficiency of the hologram disk. This has the effect of improving the yield of non-defective discs and making it possible to provide low-grade and high-quality Volograph J discs.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the outline of the operation of optical scanning using a hologram disk, Fig. 2 is a diagram for BQm of the method for creating the hologram disk, and Fig. 3 is a diagram for explaining the operation of optical scanning using a hologram disk. l] A diagram for explaining the configuration of the hologram disk, FIG. 4 is a diagram for explaining the conditions of the light beam used to create the hologram disk, and FIG. 5 is a diagram for creating the compensation bologram according to the present invention. FIG. 6, which is a diagram for explaining another method, is a diagram showing another application example of the present invention. In the figure, ■ is a light beam for facenos 1-12, 3 is a diffracted light, 4 is a projection surface, 5 and 51 are transparent disks, 6 is an aperture, and 7
are masks, 8 and 9 are light beams, 10, 11 and 22 are hologram disks, 12, 121, 122 and 123 are Borodaram layers, 13, 17 and 23 are plane waves, 14, 18 and 24 are spherical waves, 15 and 16 are 19 and 20 are interference fringes (PoI: 1 gram), and 2] is a masked Borodalum disk. Figure 4 (A) CB)゛\Q

Claims (2)

[Claims] (1) Each hologram layer is made up of a hologram layer and a support body, and the same hologram is formed on each hologram layer. In the two supported bologram disks, one of the corresponding portions of the hologram layer is removed, and then the hologram layers are joined to each other so that the corresponding portion is located in the removed portion. A hologram disc. (2) The hologram disk according to claim 1, wherein hologram disks each consisting of a plurality of facet holograms are joined together. (The hologram on the 31-th hologram disk is formed using two light beams that have the same wavefront and opposite propagation direction as the two light beams used to form the hologram on the other hologram disk. A hologram disk according to claims 1 and 2, characterized in that: