JP2001134948A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the accurate reading of informant by reducing the adverse effect of refracted light beams of adjacent hologram patterns due to the deviation, etc., of an optical recording medium to a reading direction nearly perpendicular to the reading direction. SOLUTION: Information CGH patterns 40 are recorded on the optical recording medium 10 so that the phase of the arrangement in the reading direction of the array of adjacent information CGH patterns 40 is deviated to reduce the influence of the adjacent information CGH patterns 40. Also, in the information CGH patterns 40 existing in the same column, the information CGH patterns 40 are recorded on the optical recording medium 10 in such a manner that the information CGH patterns 40 of odd numbered row and the information CGH patterns 40 of even numbered row are set to diffract the incident light to the different directions so that the image forming patterns projected from the information CGH patterns 40 of even numbered row and odd numbered row are not laid over on the light recording surface 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical recording medium, and more particularly to an optical recording medium suitable for a prepaid card, a credit card, a certification card, and the like.

[0002]

2. Description of the Related Art Current credit cards, cash cards, and the like have a magnetic recording portion called a magnetic stripe as a recording means, and a balance and an identification number for confirming the identity as necessary are recorded. With the current prepaid card, the record such as the balance is changed as the card is used. These card-type recording media are convenient to carry,
It contributes to a so-called cashless society without the hassle of giving and receiving cash. On the other hand, since these card-type recording media have a magnetic recording layer, the recorded contents can be easily read and forgery is easy. Telephone cards and pachinko parlors' prepaid cards are often forged in large quantities, which has become a social issue.

In order to cope with counterfeiting, complicated magnetic recording systems and IC cards have been proposed in place of conventional simple magnetic recording systems, but there is a problem that the cost is high.
It has not yet become widespread. Japanese Patent Laid-Open No. 3-7 / 1990 discloses a device using a diffraction grating or a hologram as optical recording.
No. 1383, JP-A-5-73738, JP-B-7-97388 and the like. These are to determine whether the reflection intensity of the light in the hologram is a predetermined value or more than a predetermined value, and to detect the optical path of the reflected light as a plurality of different ones by a diffraction grating or a hologram. It is useful to identify whether it is a fake or a counterfeit. However, it is not suitable for recording other complicated information, such as the amount of a prepaid card, a personal identification number and a card number in a cash card, and it takes time and effort to manufacture the card. Therefore, it is extremely costly and difficult to realize.

FIG. 10 is a schematic diagram showing a state of diffraction.
FIG. 10A is a schematic diagram illustrating the state of diffraction as viewed from the side of the diffraction grating surface. FIG. 10B is a schematic diagram illustrating the state of diffraction as viewed from above the diffraction grating surface. When the diffraction grating 38 having the optical diffraction grating pitch p is irradiated with a coherent laser beam from the light source 36, the incident light beam causes a diffraction phenomenon. The relationship between the pitch p of the diffraction grating 38, the wavelength λ of the light from the light source 36, and the diffraction angle θ (radian) can be expressed by ± n · sin θ = p / λ (n is a natural number including 0). When n = 0, it is called the 0th-order diffracted light, and is transmitted or reflected light of undiffracted light. The zero-order diffracted light is shown in FIG.
The transmitted light at 0 (a) becomes reflected light if the diffraction grating 38 has reflectivity. On the other hand, if the diffraction grating is symmetric at ± n, the amount of diffracted light is equal. As n increases, higher-order diffracted light is generated, but the amount of the diffracted light decreases. Considering only n = 1, the diffraction grating 3
8, three light beams are generated. Such a light beam has a finite thickness, and the conical light beam that forms an image on the light receiving surface has substantially the same size as the hologram pattern on the optical recording medium.

If the diffraction grating 38 is parallel, one-dimensional diffracted light is generated, and the light is diffracted in the diffraction grating pitch direction as shown in FIG. According to the present invention, instead of the parallel diffraction grating 38, a grating arranged in a specific pattern in both the horizontal and vertical directions is created, and computation is performed using a computer so that the diffracted light is two-dimensionally arranged.
(Computer generated hologram). In this specification, CGH arranged on an optical recording medium is referred to as a diffraction grating, a hologram pattern, or a CGH.
It may be called a GH pattern.

FIG. 11 is a configuration diagram schematically showing a manufacturing process of an optical recording medium using CGH. The manufacturing process of the optical recording medium shown in FIG. 11 was invented by the present inventors prior to the present invention, and is disclosed in JP-A-10-143929. The image is represented as a hologram, the electron beam exposure device 22 is driven using the data, and the interference fringes of the hologram are precisely drawn by the electron beam 30 to form the primary recording medium 24, which is further etched to light An apparatus and method for producing a master of the recording medium 10 and manufacturing the optical recording medium 10 from the master are disclosed.

When a prepaid card is manufactured as the card-type optical recording medium 10, for example, a plurality of hologram patterns 12 as recording portions are arranged on a predetermined area of the optical recording medium 10 on the prepaid card. Now, a case where character information and an image signal are recorded on each of the hologram patterns 12 will be described. For example, if the signal to be recorded is a character signal, it is input to the input terminal IN1 and further to the image signal conversion circuit 14. On the other hand, if the signal to be recorded is an image signal, it is input to the input terminal IN2.

FIG. 12 is a schematic diagram showing a means for obtaining a hologram interference fringe pattern from a two-dimensional image. The image signal conversion circuit 14 converts the character signal represented by the code information of the input digital signal into an image signal of a two-dimensional image dot pattern constituting the input data 32 shown in FIG.

This image signal is supplied to a numerical operation device 18 via a switch 16 or a multiplexer. The numerical operation device 18 obtains a numerical value for obtaining a holographic interferogram which is an interference fringe pattern of a hologram from a two-dimensional image dot pattern image signal without irradiating interference light using a predetermined algorithm. Numerical calculation device 1
As 8, it is preferable to use a computer capable of high-speed operation.

The numerical operation device 18 is configured to output coordinate data according to the resolution of an electron beam exposure device 22 described later. Also, before actually drawing,
The coordinate data obtained by the numerical operation is fed back and compared with the input data 32, and recalculation is performed a plurality of times in order to reduce an error between the two.

The coordinate data output from the numerical calculation device 18 is converted into a signal of a predetermined format by an encoder 20 and input to an electron beam exposure device 22. The electron beam exposure apparatus 22 is originally used to draw a circuit arrangement pattern when an IC or LSI is manufactured. Here, the output data 34 which is the interference fringe pattern shown in FIG. It is used for drawing on the recording medium 24. The primary recording medium 24 is used to distinguish it from the optical recording medium 10 as a final product. 1
As the next recording medium 24, a recording medium in which a photoresist which is a photosensitive resin as a medium to be exposed is coated on a substrate such as glass is used. The primary recording medium 24 is attached to a stepper 26. Stepper 26 is an electron beam exposure apparatus 2
It is possible to move on a plane perpendicular to the electron beam 30 by a signal from 2. In the drawing by the electron beam 30,
Compared to drawing by a laser beam used in the manufacture of a conventional optical recording medium, it is possible to draw a very fine and precise pattern, which is suitable for drawing a pattern of interference fringes of a hologram.

The primary recording medium 24 is processed as a photomask master, a plurality of secondary recording media are prepared from the photomask master by exposure, and an optical disc manufacturing process 28 is performed using the secondary recording medium as a master. It is also possible to manufacture the optical recording medium 10 as a final product.

Assuming that data composed of 300 characters of English characters (including numbers) is to be recorded on the optical recording medium 10, character string data serially input from the input terminal IN1 is sequentially transmitted to the image signal conversion circuit 14. The image signal is converted into an image signal, subjected to a numerical operation process by a predetermined algorithm in a numerical operation device 18, converted into data in a predetermined format by an encoder 20, supplied to an electron beam exposure device 22, and deflected by an electron beam 30. Then, drawing is performed on the primary recording medium 24. At this time, the electron beam exposure device 22
6, the primary recording medium 24 is moved in the XY axis direction on a plane perpendicular to the electron beam 30 so that the hologram pattern 12 has three rows and 100 recording portions are arranged in each row.

FIG. 13 is a schematic diagram showing a hologram pattern arrangement on a conventional optical recording medium. Here, five rows of hologram patterns are arranged on the optical recording medium. The hologram patterns in the first, second, fourth, and fifth rows are information CGH patterns 40, and the hologram patterns in the third row are control CGH patterns. The information CGH pattern 40 includes character information and image information, and the control CGH pattern 42 is used to control the reading position when information is read from the information CGH pattern 40 by transporting the optical recording medium 10. The hologram patterns have a square arrangement in which the lengths in the X-axis direction and the Y-axis direction are equal, and the lengths between the hologram patterns are also equal. Note that the X-axis direction is defined as the reading direction, that is, the transport direction, and the row in the X-axis direction is called a column, and the row in the Y-axis direction is called a row. X
The axial direction is the direction in which the optical recording medium is transported, and the Y-axis direction is a direction substantially perpendicular to the transport direction. Conventionally, a non-signal area without a hologram pattern area is provided on the optical recording medium 10 to create a gap between different hologram patterns to avoid the influence of an adjacent hologram pattern.

The five circles on the first line in FIG. 13 represent irradiation beams. Four of the five irradiation beams irradiate the information CGH patterns 40 in the first, second, fourth, and fifth columns, and the diffracted light is divided into four imaging patterns as shown in FIG. Are simultaneously projected on the light receiving surface. At this time, the read timing of the information CGH pattern 40 is controlled by the control CGH pattern 42. Different control C
When the ratio of irradiating the GH pattern 42 becomes equal, that is, the control CGH pattern 42 of A and the control CG of B
At the boundary of the H pattern 42, the information CGH pattern 4
A 0 is read.

When the optical recording medium is conveyed in the X-axis direction, during the transition from the first row to the second row, for example, in the first column information CGH pattern, the first row of the first column information CGH pattern is displayed. The imaging pattern “A” appears bright, and gradually disappears, and the imaging pattern “A” in the second row appears bright. This is because, as the optical recording medium 10 is transported in the X-axis direction, the amount of light applied to the information CGH pattern 40 in each row changes, and the diffracted light appearing on the light receiving surface changes.

FIG. 15 is a graph showing a change in the signal intensity of the information CGH pattern 40 due to the displacement of the optical recording medium 10 in the Y-axis direction in the conventional hologram pattern arrangement shown in FIG. The horizontal axis represents the position of the displacement of the medium in the Y-axis direction, and the vertical axis represents the signal intensity of the information CGH pattern 40. The graph plotted with ◆ is the first column information CG
The signal intensity of the H pattern 40 is shown, and the graph plotted with □ represents the signal intensity of the second column information CGH pattern 40. First column information CGH pattern 40 and second column information CGH
When the diffracted light irradiates the intermediate position of the pattern 40, the first
The column information CGH pattern 40 and the second column information CGH pattern 40 have the same signal strength.

FIG. 14 is a schematic diagram showing another hologram pattern arrangement on a conventional optical recording medium. The information CGH pattern 40 shown in FIG. 14 is twice as long in the Y-axis direction as compared to the arrangement in FIG. 13, and is arranged without a gap in the Y-axis direction. FIG. 16 is a graph showing a change in the signal intensity of the information CGH pattern 40 due to the displacement of the optical recording medium 10 in the Y-axis direction in the conventional hologram pattern arrangement shown in FIG. First column information CGH pattern 40
When the diffracted light irradiates an intermediate position between the CGH pattern 40 and the second column information CGH pattern 40, the respective signal intensities become equal to 0.5. The signal intensity of the crosstalk in FIG. 14 is larger than the signal intensity of the crosstalk in FIG. 13, and it can be seen that the hologram pattern arrangement shown in FIG. 14 is more affected by the adjacent hologram patterns than the hologram pattern arrangement shown in FIG. .

[0019]

When reading an optical recording medium, a reading shift may occur in the Y-axis direction. Due to such a shift in reading in the Y-axis direction, the image forming position of the hologram pattern on the light receiving surface also shifts.
As a result, another hologram pattern may form an image at a position where a certain hologram pattern is to be formed on the light receiving surface, and the hologram pattern cannot be read accurately.

If the irradiation beam shape is set to be wide, the diffracted light becomes bright in a wide range, but the adjacent hologram pattern is also irradiated. For this reason, in the conventional hologram pattern arrangement, the influence of the adjacent hologram pattern appears, and it becomes difficult to accurately read the hologram pattern.

According to the present invention, when reading an optical recording medium having a two-dimensionally arranged hologram pattern, the influence of diffracted light of an adjacent hologram pattern due to movement of the optical recording medium in the Y-axis direction or the like is reduced, so that accurate information can be obtained. It is an object of the present invention to provide an optical recording medium capable of reading and increasing the density of a hologram pattern.

[0022]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, in the present invention, in order to reduce the influence of adjacent hologram patterns, the hologram patterns on the optical recording medium are shifted so that the arrangement of adjacent hologram pattern arrays in the reading direction is shifted. Record

That is, according to the present invention, in an optical recording medium in which a plurality of hologram patterns are linearly arranged in a plurality of columns in a reading direction and a plurality of rows in a direction substantially perpendicular to the reading direction, the hologram patterns in adjacent columns are arranged. An optical recording medium is provided, wherein the plurality of hologram patterns are arranged so that phases of arrangement of the hologram patterns in a reading direction are mutually shifted.

In view of the above problem, according to the present invention, in the hologram patterns existing in the same column, even-numbered hologram patterns and odd-numbered hologram patterns are set so as to diffract incident light in different directions, and optical recording is performed. A hologram pattern is recorded on a medium.

According to the present invention, in an optical recording medium wherein a plurality of hologram patterns are linearly arranged in a plurality of columns in a reading direction and a plurality of rows in a direction substantially perpendicular to the reading direction, When some of the rows are irradiated with predetermined incident light, the hologram patterns in the odd-numbered rows and the hologram patterns in the even-numbered rows in the same column diffract the incident light in different directions, respectively. An optical recording medium characterized in that the hologram patterns are arranged.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> A preferred first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a hologram pattern arrangement according to the first embodiment of the optical recording medium of the present invention. In the optical recording medium, a plurality of diffraction gratings are linearly arranged in a plurality of columns in a reading direction and in a plurality of rows in a direction substantially perpendicular to the reading, and the phases of the diffraction gratings in adjacent columns in the reading direction are shifted in phase. The diffraction grating is recorded as follows. FIG. 1 shows a case where the phases of the arrangement of adjacent columns are shifted by π. As is apparent from comparison with the conventional hologram pattern array shown in FIG. 13, the first column information CGH pattern 40, the second column information CGH pattern 40, and the fourth column information C
It appears that the GH patterns 40 and the fifth column information CGH patterns 40 are alternately arranged. Therefore, in this specification, the arrangement in which the diffraction gratings are arranged so that the phases are shifted as shown in FIG. 1 is referred to as a staggered arrangement.

FIG. 2 is a schematic diagram showing another hologram pattern arrangement in the first embodiment of the optical recording medium of the present invention. Rectangular information CGH pattern 40
Are arranged in a staggered grid pattern. This is obtained by setting the length in the Y-axis direction of the information CGH 40 of the square staggered arrangement shown in FIG. 1 to be twice as long. As is apparent from comparison with the conventional hologram pattern arrangement shown in FIG. 14, the first column information CGH pattern 40 and the second column information CGH pattern 40, and the fourth column information CGH pattern 40 and the fifth column information C
The GH patterns 40 are alternately arranged.

FIG. 17 is a schematic diagram showing an embodiment of an apparatus for reading a hologram pattern on an optical recording medium. FIG. 17A is a side view of an apparatus for reading a hologram pattern on an optical recording medium, and FIG. 17B is a top view of an apparatus for reading a hologram pattern on an optical recording medium. In order to read the information CGH pattern 40 of the optical recording medium 10 shown in FIGS. 1 and 2, the optical recording medium 10 is arranged to be perpendicular to the paper. The optical recording medium 10 is conveyed and read in the X-axis direction, that is, in the left-right direction with respect to the paper surface. Light from the light source 36 is obliquely incident on the optical recording medium. The optical recording medium 10 has a reflection hologram pattern, and the 0th-order diffracted light becomes reflected light reflected at the same angle as the incident angle. The diffraction angle of each hologram pattern 12 is indicated based on the diffraction angle of the 0th-order diffracted light. For example, the diffraction angle of the first-order diffracted light is
The angle difference from the zero-order diffracted light becomes θ1, and the diffraction angle of the second-order diffracted light becomes the angle difference θ2 from the zero-order diffracted light. The light receiving surface 44 is provided so that these diffracted lights enter.

The imaging pattern of each hologram pattern projected on the light receiving surface 44 is a two-dimensional pattern such as the pattern shown in the output data 34 of FIG. 12B or the pattern shown in FIG. Therefore, it is preferable to use an element having a function of receiving light in a plane such as a two-dimensional CCD element as the light receiving surface 44.

FIG. 18 is a schematic diagram showing a state in which diffracted light from the optical recording medium according to the present invention is projected on a light receiving surface. FIG. 18A shows an example in which the light diffraction angle by the optical recording medium is symmetric, and FIG. 18B shows an example in which the light diffraction angle is adjusted to be asymmetric. The reflection type hologram pattern 12 is arranged on the optical recording medium. On the optical recording medium, hologram patterns 12 in five columns in the Y-axis direction and many rows in the X-axis direction are arranged, and a control CGH is provided at the center in the Y-axis direction.
A pattern 42 is arranged. FIG. 18 shows only one of many rows arranged in the X-axis direction.

The light emitted from the light source 36 is split by the spectroscope 46, and the five hologram patterns 1
2 is irradiated. For example, information CGH pattern 4 of “A”
The zero-order diffracted light has a unique diffraction angle, and an “A” imaging pattern is projected on the light receiving surface 44. Similarly "i",
Each of the information CGH patterns 40 of “U” and “D” also has a unique diffraction angle, and an imaging pattern is projected so as not to overlap the light receiving surface 44, respectively. Also, the control CGH light receiving surface 4
Reference numeral 8 denotes a CCD camera or the like for controlling the conveyance of the optical recording medium, which is installed at a position different from the light receiving surface 44 and receives the diffracted light from the control CGH pattern 42.

FIG. 7 is a schematic diagram showing various image forming patterns projected on the light receiving surface according to the first embodiment. In the case where the flow of the light beam is symmetric as shown in FIG.
When reading the hologram pattern shown in FIG. 2 and FIG. 2, an image forming pattern as shown in FIG. 7A and FIG. FIG. 7A is a diagram illustrating an imaging pattern of an odd-numbered row in the hologram pattern array illustrated in FIGS. 1 and 2. FIG. 7B is a diagram illustrating an imaging pattern of an even-numbered row of the hologram pattern array illustrated in FIGS. 1 and 2. Also, when the flow of the light beam is asymmetric as shown in FIG. 18B, unlike the case of FIG.
7C and the image forming pattern shown in FIG.
Projected to FIG. 7C is a diagram showing an imaging pattern of an odd-numbered row in the hologram pattern array shown in FIGS. FIG. 7D is a diagram showing an imaging pattern of an even-numbered row of the hologram pattern array shown in FIGS.

FIG. 5 is a graph showing the change in the signal intensity of the hologram pattern due to the displacement of the optical recording medium in the Y-axis direction in the hologram pattern arrangement of the present invention shown in FIG. The vertical axis indicates the intensity of the signal received by the light receiving surface 44, and the horizontal axis indicates the reading position of the information CGH pattern 40 in the Y-axis direction. Compared to the change in signal intensity of the conventional information CGH pattern 40 shown in FIG.
It can be seen that the influence of the overlapping of the patterns 40 is small. That is, by the hologram pattern arrangement by the staggered arrangement of the present invention, the distance between the hologram patterns is sufficiently large,
It can be seen that there is room for reading in the Y-axis direction, and the influence of adjacent hologram patterns is eliminated.

FIG. 6 is a graph showing a change in the signal intensity of the hologram pattern due to the displacement of the optical recording medium in the Y-axis direction in the hologram pattern arrangement of the present invention shown in FIG. The vertical axis indicates the intensity of the signal received by the light receiving surface 44, and the horizontal axis indicates the reading position of the information CGH pattern 40 in the Y-axis direction. In the hologram pattern array of FIG. 6 as well, the influence of the overlap of the information CGH patterns 40 adjacent in the Y-axis direction is smaller than the change in the signal intensity of the conventional information CGH pattern 40 shown in FIG.

Although it is desirable that the area of the hologram pattern is large in consideration of irradiation position control, diffraction efficiency, contamination control, and the like, conventionally, crosstalk occurs due to the influence of an adjacent hologram pattern, and the area of the hologram pattern is limited. The hologram pattern arrangement shown in FIGS. 1 and 2 can reduce the influence of adjacent hologram patterns and increase the area of each hologram pattern to twice that of the related art. In the hologram pattern arrangement shown in FIGS. 1 and 2, the phase shift is set to π, but the phase shift may be set to any value. For example, the phase shift can be set to π / 2 or 3π / 2, but when the phase is shifted by π, the crosstalk is minimized and the influence of the adjacent hologram pattern is reduced.

When reading information while transporting the optical recording medium 10 on which the hologram pattern is arranged two-dimensionally in the X-axis direction, the information can be accurately read even if the displacement of the optical recording medium 10 in the Y-axis direction becomes large. It becomes possible to read. That is, a reading error hardly occurs with respect to a shift in the Y-axis direction.

<Second Embodiment> FIG. 3 is a schematic view showing an embodiment in which the hologram patterns in the optical recording medium according to the second embodiment of the present invention are arranged differently for each row. FIG. 4 is a schematic diagram showing another embodiment in which the hologram pattern in the second embodiment of the optical recording medium of the present invention is differently arranged for each row. In the optical recording medium, information C including different information between odd-numbered rows and even-numbered rows is stored.
The GH pattern 40 is arranged. In the optical recording medium 10 shown in FIGS. 3 and 4, "A", "A",
An information CGH pattern 40 including information of “U” and “D”;
The information CGH pattern 40 including the information of “K”, “G”, “K”, and “K” is arranged in even rows. In addition, the diffraction angles of the odd-numbered information CGH patterns 40 and the even-numbered information CGH patterns 40 are set so that the imaging patterns are projected at different positions on the light receiving surface 44. In addition,
When the influence of the adjacent hologram pattern is small, FIG.
It is also possible to eliminate the gap of the information CGH pattern 40 between rows, which is a non-signal area, as shown in FIG. This allows
The read timing during the movement in the X-axis direction has a degree of freedom, so that the information CGH pattern 40 can be easily read.

FIG. 19 is a schematic diagram showing another embodiment of an apparatus for reading a hologram pattern on an optical recording medium. FIG. 19A is a side view, and FIG. 19B is a top view. The device shown in FIG. 19 is the same as the device shown in FIG. Although not shown in FIG. 17, actually,
Light incident on the light receiving surface 44 has a spread of Δθ.

The light receiving surface 44 is a rectangle having one side length of q _x and q _y . Further, since the incident light has a spread of Δθ, the imaging pattern projected on the light receiving surface 44 becomes r _x , r _y
It has the size of In general, the relationship between the size of the size and imaging the pattern of the light-receiving surface 44, is set such that _{q x> 4 × r x q} y> 4 × r y. Further, it is preferable that there is a margin of 20% or more so that the imaging patterns do not overlap each other due to movement of the imaging position. That is, it is preferable to set to be _{q x ≧ 4 × r x ×} 1.2 q y ≧ 2 × r y × 1.2.

FIG. 20 is a schematic view showing a state where diffracted light from the optical recording medium according to the present invention is projected on a light receiving surface. FIG. 20A is a schematic diagram when reading the information CGH pattern 40 in the odd-numbered row, and FIG. 20B is a schematic diagram when reading the information CGH pattern 40 in the even-numbered row. The device shown in FIG. 20 is the same as the schematic diagram shown in FIG. 18A, and the light emitted from the light source is split by the spectroscope 46 to irradiate and reflect five hologram patterns in the Y-axis direction. Then, an imaging pattern is projected on the light receiving surface 44. The optical recording medium 10 shown in FIGS. 3 and 4 is set so that the positions of the imaging patterns on the light receiving surface 44 are different between the odd-numbered rows and the even-numbered rows. Although FIG. 20 shows a case where the light diffraction angle is symmetric, it is also possible to adjust the light diffraction angle to be asymmetric as in the case of FIG. 18B.

FIG. 8 is a schematic diagram showing various imaging patterns projected on the light receiving surface according to the second embodiment. When reading the hologram patterns of the odd-numbered rows of the optical recording medium shown in FIG. 3, an imaging pattern as shown in FIG. The optical recording medium 1 shown in FIG.
When reading the information CGH pattern 40 of the even-numbered row of 0,
An imaging pattern as shown in FIG. 8C is projected on the light receiving surface 44. When diffracted light is irradiated between the odd-numbered rows and the even-numbered rows of the information CGH patterns 40, an imaging pattern is projected on the light receiving surface 44 from both the odd-numbered rows and the even-numbered rows of the information CGH patterns 40, and FIG. The imaging pattern shown in b) is obtained. When the line irradiated by the conveyance of the optical recording medium 10 in the X-axis direction changes, the light amount between the lines decreases,
An imaging pattern is projected on the light receiving surface 44 from the information CGH patterns 40 of both the even and odd rows. In this case, although the light quantity of each imaging pattern decreases, the adjacent hologram patterns are simultaneously imaged on the light receiving surface 44.
In the related art, reading is impossible due to the overlapping of the imaging patterns. However, in the present invention, reading is enabled by preventing the imaging positions from overlapping.

FIG. 9 is a schematic diagram of an imaging pattern projected on the light receiving surface when another hologram pattern is used. As in the case of FIG. 8, FIG. 9A shows the information C of the even-numbered row.
The GH pattern 40, FIG. 9 (b) shows the odd-numbered row of information CGH.
FIG. 9C is a schematic diagram of an image forming pattern projected on the light receiving surface 44 from the information CGH pattern 40 between rows. The influence of the adjacent hologram pattern can be obtained by projecting the imaging pattern from the odd-numbered information CGH pattern 40 and the imaging pattern from the even-numbered information CGH pattern 40 at different positions on the light receiving surface 44. Can be prevented. There is no restriction on the position, shape, and the like of the imaging pattern projected on the light receiving surface 44, and the user can freely select the imaging pattern. Further, by installing a plurality of light receiving means, the information CGH pattern 4
It is also possible to read 0 and read the information CGH pattern 40 of the even-numbered row from different light receiving surfaces.

[0043]

According to the present invention, information CG on the optical recording medium 10 is obtained.
Since the H pattern 40 is arranged in a staggered arrangement, the influence of the adjacent hologram pattern is reduced and the reading error is reduced. Also, when the information is read while the information CGH pattern 40 arranged two-dimensionally is conveyed in the X-axis direction. A reading error is less likely to occur with respect to the resulting shift in the Y-axis direction. Further, in the case of the staggered arrangement, since the information CGH patterns 40 are not adjacent to each other, the area of each information CGH pattern
It is possible to increase by a factor of two.

The present invention also relates to the information C on the optical recording medium 10.
When arranging the GH patterns 40, the odd-numbered rows of information CGH
Combination pattern from pattern 40 and even-numbered row information CGH
Since the image forming pattern from the pattern 40 is set so as to be projected to different positions on the light receiving surface 44, even if the image forming patterns overlap each other and reading becomes impossible in the related art, the present invention does not apply the image forming pattern. Are not overlapped, and reading becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a hologram pattern array according to a first embodiment of the optical recording medium of the present invention.

FIG. 2 is a schematic diagram showing another hologram pattern arrangement in the first embodiment of the optical recording medium of the present invention.

FIG. 3 is a schematic diagram showing an embodiment in which a hologram pattern according to the second embodiment of the optical recording medium of the present invention is arranged differently for each row.

FIG. 4 is a schematic diagram showing another embodiment in which the hologram pattern in the second embodiment of the optical recording medium of the present invention is differently arranged for each row.

5 is a graph showing a change in the signal intensity of the hologram pattern due to the displacement of the optical recording medium in the Y-axis direction in the hologram pattern arrangement of the present invention shown in FIG.

6 is a graph showing a change in signal intensity of the hologram pattern due to displacement of the optical recording medium in the Y-axis direction in the hologram pattern array of the present invention shown in FIG.

FIG. 7 is a schematic diagram illustrating various image patterns projected on the light receiving surface according to the first embodiment.

FIG. 8 is a schematic diagram showing various image patterns projected on a light receiving surface according to the second embodiment.

FIG. 9 is a schematic diagram of an imaging pattern projected on a light receiving surface when another hologram pattern is used.

FIG. 10 is a schematic diagram showing a state of diffraction.

FIG. 11 is a configuration diagram schematically showing an apparatus for manufacturing an optical recording medium using CGH.

FIG. 12 is a schematic diagram showing a means for obtaining a hologram interference fringe pattern from a two-dimensional image.

FIG. 13 is a schematic diagram showing a hologram pattern arrangement on a conventional optical recording medium.

FIG. 14 is a schematic view showing another hologram pattern arrangement on a conventional optical recording medium.

FIG. 15 is a graph showing a change in the signal intensity of the information CGH pattern 40 due to the displacement of the optical recording medium 10 in the Y-axis direction in the conventional hologram pattern arrangement shown in FIG.

16 is a graph showing a change in the signal intensity of the information CGH pattern 40 due to the displacement of the optical recording medium 10 in the Y-axis direction in the conventional hologram pattern arrangement shown in FIG.

FIG. 17 is a schematic view showing one embodiment of an apparatus for reading a hologram pattern on an optical recording medium.

FIG. 18 is a schematic diagram showing a state where diffracted light from an optical recording medium according to the present invention is projected on a light receiving surface.

FIG. 19 is a schematic view showing another embodiment of an apparatus for reading a hologram pattern on an optical recording medium.

FIG. 20 is a schematic diagram showing a state in which diffracted light from the optical recording medium according to the present invention is projected on a light receiving surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Optical recording medium 12 Hologram pattern 14 Image signal conversion circuit 18 Numerical calculation device 20 Encoder 22 Electron beam exposure device 24 Primary recording medium 26 Stepper 30 Electron beam 32 Input data 34 Output data 36 Light source 38 Diffraction grating 40 Information CGH pattern 42 Control CGH pattern 44 Light receiving surface 46 Spectrometer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Haruo Matsuo 3-12-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2C005 HA02 HB01 HB04 HB09 JB08 JB09 LA19 LB15 2K008 AA13 BB05 CC03 DD03 EE04 FF27 GG05 HH01 HH19 HH28 5B035 AA00 BB05 BC02 5D090 AA03 BB02 FF45 FF49 GG11 GG22

Claims (2)

[Claims] 1. An optical recording medium in which a plurality of hologram patterns are linearly arranged in a plurality of columns in a reading direction, a plurality of rows in a direction substantially perpendicular to the reading direction, and in a reading direction of the hologram patterns in adjacent columns. An optical recording medium, wherein the plurality of hologram patterns are arranged so that the phases of the arrangements are shifted from each other. 2. An optical recording medium in which a plurality of hologram patterns are arranged in a plurality of columns in a reading direction, a plurality of rows in a direction substantially perpendicular to the reading direction, and linearly arranged, wherein a part of the plurality of hologram patterns is provided. The plurality of hologram patterns are arranged such that when irradiated with predetermined incident light, the hologram patterns in the odd-numbered rows and the hologram patterns in the even-numbered rows of the same column diffract the incident light in different directions, respectively. An optical recording medium characterized by being performed.