JP2001266399A - Optical pickup of information reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup capable of improving attaching precision, easily performing an optical adjustment and attaining miniaturization and a thin shape. SOLUTION: A light emitting element 12, a convex lens 14 and a diffraction grating 15 are arranged on a straight line in the horizontal direction relative to an optical recording medium 18, and an imaging device 19 is arranged in the vertical direction relative to the optical recording medium 18 and moreover in the direction orthogonal to the arrangement direction of the light emitting element 12, the convex lens 14 and the diffraction grating 15. Also, a hologram pattern on the optical recording medium 18 is irradiated by reading beams 16, and a beam splitter 17 having a half mirror surface 17a for image forming diffracted light from the hologram pattern onto the imaging device 19 is provided. Thus, attaching to a base 22 and the optical adjustment are easily performed, and miniaturization and the thin shape are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup of an information reading apparatus for reading information from a recording medium on which information is recorded by a hologram image or the like, and more particularly, to a prepaid card, a credit card, a cash card, a certification card, and the like. The present invention relates to an optical pickup of an information reading device for simultaneously reading information from a plurality of holograms recorded on a recording medium.

[0002]

2. Description of the Related Art Conventionally, various cards such as a payment card, a credit card, and a certification card have been used, but a magnetic recording portion on which information is recorded by these cards is easily forged or falsified. For this reason, card-type optical recording media are attracting attention as an alternative to magnetic recording. Among optical recording media, those using holograms have been given particular importance as being effective for forgery and falsification. Prior to the present invention, the present applicant has already developed an apparatus for recording / reproducing a plurality of hologram patterns on a substrate as an optical recording medium recording / reproducing apparatus.
A patent application has been filed as No. 27. The hologram used here is not a rainbow hologram that irradiates natural light and recognizes information with the naked eye, but can reproduce information by irradiating monochromatic light and projecting its diffracted light on a screen or an image sensor. CGH (computer
A hologram called a "generated hologram" is used.

FIG. 5 shows an example of a conventional optical pickup.
1 is a light emitting element, 2 is a convex lens for condensing laser light on the imaging element 5, 3 is a diffraction grating for dividing the laser light into a plurality of reading beams 8, and these light emitting element 1, convex lens 2, The diffraction grating 3 is housed integrally in the optical lens barrel 9.

In this optical pickup, a laser beam 7 output from a light emitting element 1 is condensed by a convex lens 2 and passes through a diffraction grating 3 to form a plurality (odd number) of read beams 8.
And irradiates the hologram pattern 10 on the optical recording medium 6 obliquely. The reflected diffraction light output from the hologram pattern 10 forms an image on the light receiving element 5 and is received by the imaging element 5. The information recorded on each hologram 10 was read by converting the reading beam 8 into an electric signal.

Here, as shown in FIG. 6, when each reading beam 8 is irradiated in an inclined state with respect to each data string 11 composed of a plurality of (three in FIG. 6) hologram patterns 10. Since the light amount difference occurs on the light receiving surface of the imaging device 5 that receives the diffracted light and the image is displaced in the reading direction, the inclination △ θ of the reading beam 8 with respect to the data sequence 11 is minimized. The adjustment is performed by rotating the optical barrel 9 as described above.

[0006]

In the above-mentioned conventional optical pickup, the optical barrel 9 and the image pickup device 5 are mounted on the base 4 at an angle, so that the mounting accuracy is ensured and the optical pickup is secured. Adjustment workability was poor.

[0007] Further, since the respective components are mounted obliquely so as to irradiate the laser beam obliquely to the optical recording medium, the size of the optical pickup in the height direction is increased, and it is difficult to reduce the size and thickness of the optical pickup. Met. As a result, the size and thickness of the entire method reading apparatus have been affected.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical pickup capable of improving the mounting accuracy, facilitating the optical adjustment, and reducing the size and thickness.

[0009]

According to another aspect of the present invention, there is provided an optical pickup of an information reading apparatus for reading information recorded on a plurality of holograms on an optical recording medium, the light source emitting monochromatic light. A light-collecting unit that collects light emitted from the light source, a diffraction grating that separates the light output from the light-collecting unit into a plurality of beams, and a plurality of beams that are separated by the diffraction grating. The plurality of holograms on the optical recording medium are directed to irradiate the plurality of holograms, and the light beam separating means into which diffracted light output from the plurality of holograms is incident; and the diffraction light output from the light beam separating means. Image pickup means for receiving light, wherein the light source, the light condensing means and the diffraction grating are arranged on a straight line in a horizontal or vertical direction with respect to the optical recording medium, and An optical pickup for an information reading apparatus, wherein an element is arranged in a horizontal or vertical direction with respect to the optical recording medium and in a direction perpendicular to an arrangement direction of the light source, the condensing means, and the diffraction grating. What you want to do.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the optical pickup of the information reading apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic cross section of a first embodiment of the optical pickup according to the present invention.

In FIG. 1, a light emitting element (light source) 12, a convex lens (light collecting means) 14, and a diffraction grating 15 are arranged on a straight line in a horizontal direction with respect to an optical recording medium 18,
The imaging element 19 is arranged in a direction perpendicular to the optical recording medium 18 and at right angles to the arrangement direction of the light emitting element 12, the convex lens 14, and the diffraction grating 15. The optical pickup having the configuration shown in FIG.
2. The convex lens 14 and the diffraction grating 15 are arranged in a direction perpendicular to the optical recording medium 18, and the imaging device 19 is
8 may be arranged horizontally.

The reading beam 16 is transmitted to the optical recording medium 1.
A beam splitter (light beam separation means) 17 having a half mirror surface 17a for irradiating the hologram pattern on the hologram pattern 8 and forming an image of the diffracted light from the hologram pattern on the image sensor 19 is provided.
7 is held on the base 22 by a leaf spring 26 and a bolt 27 interposed between the image sensor 19 and the image sensor 19.

In the optical pickup having such a configuration, the laser beam 13 output from the light emitting element 12 is condensed by the convex lens 14, passes through the diffraction grating 15, and is separated into a plurality (odd number) of reading beams 16. The light is reflected by the half mirror surface 17a of the beam splitter (light separating means) 17 and irradiates each hologram pattern on the optical recording medium 18 (not shown here, but as shown in FIG. A plurality of hologram pattern rows are arranged, and a plurality of hologram patterns in one row are simultaneously irradiated with the respective reading beams 16). Then, the diffracted light reflected and diffracted by each hologram pattern on the optical recording medium 18 is supplied to the beam splitter 17 again, passes through the half mirror surface 17a, is supplied to the image pickup device 19, and is placed on the image pickup surface. Form an image.

An adjustment mechanism of the diffraction grating 15 will be described with reference to FIG. FIG. 2 shows the convex lens 14 and the diffraction grating 1 for explaining the adjustment mechanism of the diffraction grating 15.
FIG. 5 is a perspective view showing details of a structure of a leaf spring 21 holding the diffraction grating holder 5 and the diffraction grating holder 20 and omitting description of other components. The leaf spring 21 is not only a holding member, but also has a groove of the leaf spring 21 and the diffraction grating holder 2 so that the rotation angle of the diffraction grating 15 attached to the diffraction grating holder 20 can be adjusted.
The protrusions 0 are attached so as to mesh with each other.

The rotation angle of the diffraction grating 15 can be adjusted by inserting the adjustment lever 23 into a hole provided in the leaf spring 21 and sliding the adjustment lever 23 in the direction of arrow A in the figure to thereby move the leaf spring 21 in the direction of the arrow in the figure. The diffraction grating 15 is adjusted by rotating in the direction B.

Here, in the diffraction grating holder 20 to which the diffraction grating 15 is attached, the circular portion on the lower surface in the drawing of the diffraction grating holder 20 fits into the hole shape of the base 22, and the entire diffraction grating holder 20 is formed. Move in the direction of rotation. Note that the diffraction grating 15 and the diffraction grating holder 20 may have a structure integrally formed of resin or the like.

The structure of the leaf spring 21 allows the convex lens 1
Since the holding of the diffraction grating 4 and the diffraction grating 15 are performed at the same time, and the adjustment of the diffraction grating is performed by rotating the leaf spring itself, it is possible to reduce the number of parts and provide a mechanism that is simple in structure and easy to adjust. The diffraction grating 15 shown in FIG.
The same adjustment mechanism is used in a second embodiment described later.

As described above, in this embodiment, the light emitting element 12, the convex lens 14, the diffraction grating 15, and the imaging element 19 are arranged in the horizontal or vertical direction with respect to the optical recording medium 18, and the beam splitter 17 The hologram pattern is irradiated with the reading beam to form an image on the image pickup device 19 by giving an angle to the incidence and reflection of the reading beam by the half mirror surface 17a using. As a result, since it is not necessary to make an angle when attaching each component to the base 22, the shape of the base 22 is simplified, and the base 22 can be manufactured with high accuracy.
Each component can be attached to the base 22 with high accuracy.

Since the beam splitter 17 is manufactured by polishing glass or molding a resin, the beam splitter 17 can be relatively easily made higher in precision than the base 22. As a result, the number of adjustment steps is reduced, and an inexpensive optical pickup can be provided. Furthermore, by mounting each component horizontally or vertically, efficient arrangement becomes possible, and a compact and thin optical pickup can be realized. Note that the above effects obtained from this embodiment can also be obtained from the following second and third embodiments.

Next, a second embodiment of the optical pickup according to the present invention is shown in FIG. Since the basic configuration is the same as that of the first embodiment, only different components will be described here.

In this embodiment, the beam splitter 17 is used.
Are arranged only on the incident surface side of the reading beam 16 with respect to the half mirror surface 17a, and the half mirror surface 17a is provided on the inclined surface of the beam splitter 17. The beam splitter 17 includes a holding spring 24.
It is fixed at. With such a configuration,
Since the holding of the beam splitter 17 is simpler than that of the first embodiment and a cheaper beam splitter can be used, the cost can be further reduced.

FIG. 4 shows a third embodiment of the optical pickup according to the present invention. Since the basic configuration is the same as the first and second embodiments, only different components will be described here.

In this embodiment, the diffraction grating and the beam splitter are integrated. The beam splitter 25 made of a transparent resin has a configuration in which a fine groove is provided on the laser beam incident surface to form a diffraction grating 25a, and a half mirror surface 25a is provided on the opposite inclined surface. With such a configuration, the positional accuracy between the beam splitter 25 and the diffraction grating 25b is improved, and the diffraction grating 2
Since the rotation adjustment of 5b becomes unnecessary, there is an effect that the assemblability is improved.

[0024]

As described above, the optical pickup of the information reading apparatus according to the present invention can easily arrange each component as compared with the conventional optical pickup, and is designed to be small and thin. Since the freedom is increased and the structure of the base is simplified, the cost of parts can be reduced.

When the structure for holding the convex lens and the diffraction grating and for adjusting the rotation of the diffraction grating is integrated, the adjustment of the diffraction grating can be easily performed.

Further, when the diffraction grating and the beam splitter are integrally formed, there is no need to adjust the rotation of the diffraction grating, which simplifies the assembly and provides an inexpensive optical pickup. is there.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a first embodiment of an optical pickup of an information reading apparatus according to the present invention.

FIG. 2 is a partial perspective view for explaining a diffraction grating adjustment mechanism according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of the optical pickup of the information reading device of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the optical pickup of the information reading apparatus of the present invention.

FIG. 5 is a configuration diagram showing a conventional optical pickup.

FIG. 6 is a diagram for explaining an irradiation position of a hologram pattern and a reading beam.

[Explanation of symbols]

 Reference Signs List 1,12 Light emitting element (light source) 2,14 Convex lens (condensing means) 3,15,25b Diffraction grating 4,22 Base 5,19 Image pickup element (imaging means) 6,18 Optical recording medium 7,13 Laser beam 8 , 16 read beam 10 hologram pattern 17, 25 beam splitter (beam separation means) 17a, 25a half mirror surface

Claims (3)

[Claims] 1. An optical pickup for an information reading apparatus for reading information recorded on a plurality of holograms on an optical recording medium, comprising: a light source for emitting monochromatic light; An optical unit, a diffraction grating for separating the light output from the condensing unit into a plurality of beams, and guiding the plurality of beams separated by the diffraction grating to each of the plurality of beams on the optical recording medium. Irradiating the hologram of the plurality of holograms, a light beam separating means into which the diffracted light output from the plurality of holograms is incident, and an imaging means for receiving the diffracted light output from the light beam separating means, the light source; The light condensing means and the diffraction grating are arranged on a straight line in the horizontal or vertical direction with respect to the optical recording medium, and the imaging device is moved in the horizontal or vertical direction with respect to the optical recording medium. And the light source, the optical pickup of the information reading apparatus to the arrangement direction of the focusing means and said diffraction grating, characterized in that arranged at a right angle. 2. A light beam for an information reading apparatus according to claim 1, further comprising a leaf spring member holding said condensing means and said diffraction grating and having a function of adjusting rotation of said diffraction grating. pick up. 3. An optical pickup for an information reading apparatus according to claim 1, wherein said diffraction grating and said light beam separating means are integrally formed.