JPS60117213A - Hologram scanner - Google Patents

Abstract

PURPOSE:To obtain a hologram scanner for which a smaller size module for scanning and condensing of laser light is used by forming a sloped part to a rotating member and disposing a hologram on the sloped part. CONSTITUTION:A hologram 27 is mounted on the circular conical surface of a rotating member 22. Laser light 26 is converted to a plane wave by a collimator 25 and is made incident through the window 32 of the rotating member to the hologram 27, by which the light is diffracted. The diffracted light is scanned by the rotation of the rotating member so as to irradiate an object to be read. The scattered light 28 of the signal reflected from the object to be read returns again to the hologram 27, by which the light is converted to the plane wave parallel with the revolving shaft. The plane wave is reflected by a signal light reflection mirror 29 mounted to the rotating member and is directed toward the bottom end face of the rotating member while the wave is converged. The converged light passes through a filter 30 and forms the image on a semiconductor detector 31. Since the compact module for scanning and condensing is constituted in the rotating member in the above-mentioned way, the rotating member is smaller in diameter and since the inside of the rotating member is utilized with high density, the small-sized scanning and condensing system is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a hologram scanner that diffracts and scans laser light using a hologram and simultaneously focuses signal scattered light from an object to be read using the same hologram.

Background of the Technology Recently, in order to save labor at registers at supermarkets, etc., code reading devices have come into use that read the code printed on the exterior of products and input it into a computer. It's coming. A hologram scanner that uses a hologram as both a light converging element and a light deflection element to converge and scan a laser beam is suitable for this device, and therefore, this hologram scanner is used as an optical scanning section in a bar code reading device.

Figure 1 is a diagram for explaining the basic 4'jtt configuration of a barcode reading device.
4 is a hologram disk having a hologram of imaginary number i1/j, 5 is its drive motor, 6 is a window opened on the operation surface of the housing, 7 is a scanning light, 8 is a signal light, and 9 is a scanning light. A perforated mirror for separating signal light, 10 a condensing lens, 11 a photodetector, and 12 a bar code printed on the exterior of the product. In operation of this device, light passing through a perforated mirror 9 is converged and deflected by a hologram disk 4 to scan a barcode 12 on a product.

The light 8 modulated by the bar code 12 is converged again on the hologram disk 4, reflected on the perforated mirror 9, passed through the lens 10, and detected by the photodetector 11.

Prior Art and Problems Such a conventional hologram scanner consists of an optical scanning section consisting of a hologram disk and a motor, an input optical system consisting of a laser tube or laser diode, a laser diode, a perforated mirror, a lens, and a filter. , a recombination system consisting of a photodetector, a scanning/turning synthesis mirror system consisting of a group of multiple mirrors, and a mirror that connects these components are assembled in one housing. Therefore, these component parts must be arranged with high precision, and since there are a large number of parts, extremely high assembly precision is required for each part. Therefore, there are disadvantages in that assembly is not easy and adjustment is required after assembly.

Furthermore, since the hologram disk in the optical scanning section cannot process light internally, the optical path area is shared between the incident light from the optical scanning section to the perforated mirror, etc., and the re-imaging light separation element 1. Other than that, each prefecture is separated and the spatial density is low, which makes it difficult to conduct scanning and focusing systems.
There is a drawback in that it is difficult to integrate these into a module, thereby making the scanner smaller and lower in price.

OBJECTS OF THE INVENTION In view of the above-mentioned conventional drawbacks, the present invention provides a miniaturized laser beam scanning/focusing module. The object of the present invention is to provide a hologram scanner with a high level of accuracy.

According to the present invention, a hologram attached to or formed on a rotating member diffracts and scans a laser beam, and at the same time collects scattered light (No. This is achieved by providing a hologram scanner that emits light, characterized in that a sloped portion is formed on the rotating member and the hologram is disposed on the sloped portion.

Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a sectional view of essential parts for explaining the first embodiment of the hologram scanner according to the present invention.

In the figure, 20 is a pace, 21 is a motor, 22 is a rotating member, 23 is its upper plate, 24 is a semiconductor laser, 2
5 is a collimator, 26 is a laser beam, 27 is a hologram,
28 is a signal scattered light, 29 is a signal light reflecting mirror, 30 is a filter, and 31 is a semiconductor photodetector.

In this embodiment, a motor 2 is mounted on the pace 20 as shown in FIG.
1 is attached to the shaft, and a hollow (or solid) transparent spinning top-shaped rotating member 22 is fixed to the shaft. The rotating part 22 has a shape that is a combination of a truncated cone and a cylinder, and has a film-like hologram 27 on its conical surface, and a Fresnel type parabolic mirror as a signal light reflecting mirror z9 on the top plate 23 at the top of the cylinder. (Flat borders or concave mirrors may also be used.) are attached to each. Further, the pace 20 is provided with a semiconductor laser 24 in the upper part and a semiconductor photodetector 31 in the lower part on the center line of the rotation axis. Note that a circular belt-shaped window 32 through which the laser beam passes is formed in the upper surface plate 23 of the rotating member and the signal light reflecting mirror 29. The laser beam 26 emitted from the semiconductor laser 24 is converted into a plane wave of an appropriate diameter by the collimator 25, and enters the hologram 27 through the window 32 of the rotating member. The laser beam diffracted by the hologram is scanned by the rotation of the rotating member 220 and illuminates the object to be read. The signal scattered light 28 reflected from the object to be read returns to the one-segment hologram 27, where it is converted into a plane wave parallel to the rotating part 1, and the signal mounted on the rotating member is reflected by a reflecting mirror 29 and converged. The image is directed toward the lower surface of the rotating member, passes through a filter 30, and is imaged into a semiconductor detection area.

In this way, in this example d, the incident) is
3! The optical system is densely integrated into the rotating member, creating a comprehensive scanning and condensing module. has been completed.

In addition, the rotating member has the same r, l>'(: The straight line 11 is smaller than that of a hologram disk with an area of This makes scanning and scanning much smaller than before.
It is a light condensing system.

The hologram is created using the rotating member 22 as shown in FIG. 3a.
It can be formed by interfering a spherical wave 33 and a plane wave 34 parallel to the rotation axis from obliquely downward on the emulsion attached to the circle J/IL table. In this case, a spherical wave 33 and a plane wave 34
The incident angle α with respect to the emulsion surface 27a is preferably an equal angle. If the emulsion is created in this way, the Bragg plane formed inside the emulsion will be perpendicular to the emulsion surface, so there will be no change in the Bragg angle due to phenomena such as shrinkage of the emulsion thickness, swelling, or changes in the refractive index due to processes such as fixing. High first use efficiency can be obtained during regeneration. Further, the emulsion may be applied directly to the truncated cone, but it is also possible to wrap a fan-shaped film 35 around it as shown in FIG.

Further, the rotating member may be a combination of a truncated pyramid and a cylinder as shown in FIG. 4a, or a truncated pyramid and a prism as shown in FIG. Alternatively, as shown in FIG. 4C, a cylinder may be cut diagonally to provide two flat surfaces.

In this case, it is sufficient to create a film hologram on a plane in advance, cut it to a predetermined size, and attach it to the rotating member, making the creation of the hologram extremely simple. Furthermore, the second
In the embodiments shown in the figures and FIG. 4, the cylinder, column, or prism at the upper part of the rotating member is not necessarily necessary, and only a truncated cone or truncated pyramid at the lower part may be used.

Further, by using the signal light reflecting mirror 29 which has a characteristic of converging a plane wave to one point, and by placing the detector on the rotational center axis, stable signal light detection can be always performed regardless of the rotation of the rotating member. In addition, the laser beam incidence part can be formed by opening an annular window 36 as shown in FIG.
7 and make only this part a parallel flat plate. According to the method shown in Fig. b, the rotating member is completely sealed, thereby preventing the intrusion of clumps and the like.

FIG. 6 is a diagram for explaining the second embodiment, in which a is a sectional view and b is a perspective view. In this figure, the same parts as those of the first embodiment shown in FIG. 2 are denoted by the same reference numerals.

In this embodiment, the quickly rotating part 41 shown in FIG. A photodetector 31 is provided at the bottom of each pace 2 ( ). In this embodiment configured in this way, both the signal light reflector 29 and the photodetector 31 are fixed to the pace 20, so it is sufficient that the relative relationship between them is satisfied, and the signal light reflector 29 and the drive motor This has the advantage that alignment of the rotation axis of the photodetector 31 is not required and the degree of freedom in the installation position of the photodetector 31 is increased. Also, the signal light reflector 2
90 area is only about half that of the first embodiment, and the light entrance part also needs to be one hole instead of an annular ring as shown in Fig. 5, which has the advantage of increasing the effective light-converging area. .

Effects of the Invention As described in detail, the hologram scanner according to the present invention provides a hologram on the inclined surface of a rotating member, thereby modularizing the laser beam scanning and edge light relationships, making it possible to reduce the size and cost. It is very effective.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the basic configuration of a conventional .-code reading 'dM, FIG. The figure is a diagram to explain the method of creating a hologram, Figure 4 is a diagram to explain the shape of the rotating part, Figure 5 is a diagram to explain the window of the signal light reflecting mirror, and Figure 6 is a diagram to explain the window of the signal light reflecting mirror. FIG. 2 is a schematic diagram illustrating a second embodiment of a hologram scanner according to the present invention. In the drawings, 201 shows a pace, 21 a motor, 22 a rotating member, 24 &:, an I semiconductor laser, 27 a hologram, 29 a signal yc: reflection '9J', and 31 a semiconductor photodetector. Patent applicant Isu 10 patent attorney company patent attorney Akira Ki Patent attorney Kazuyuki Nishidate Patent attorney LB Yukio Patent attorney Yama 1” Akiyuki! :$2 Figure 3 Figure 4 (.) (b) Figure 5 (a) (b) Figure 6 (G) (b) Written amendment December 25, 1980 Mr. Manabu Shiga, Commissioner of the Patent Office 1. Indication of the case 1982 Patent Application No. 22C425 2. Name of the invention Hologram scanner 3. Person making the amendment Relationship to the case Name of patent applicant (522) Fujitsu Limited 4. Agent (3 others) 5 ,? ili Correct subject matter (1) "Claims" column of the specification (2) Contents of amendments to "Detailed Description of the Invention" column 6 of the specification (1) Claims of the specification attached Correct as shown. (2) The statement ``And this object will be achieved.'' in the 6th to 13th lines of page 5 of Specification-W is amended as follows. [The purpose of this invention is to form a sloped surface inclined with respect to the rotational axis of the rotational member on the surface of the rotational member, and to arrange a hologram for optical scanning on the sloped surface BIS4. A complete hologram scanner has been achieved. 7. Amended list of attached documents Claims 1 copy 2. Claims Ram scanner.

Claims (1)

[Scope of Claims] 1. A hologram scanner that diffracts and scans a laser beam by a hologram attached to or formed on a rotating member, and simultaneously condenses 4J@ scattered light from an object to be read by the same hologram, A hologram scanner, characterized in that a rotating member has a sloped portion and the hologram is disposed on the sloped portion. 2. A signal light reflecting mirror such as a plane mirror, concave mirror, or parabolic mirror is mounted or formed on the upper surface of the rotating member coaxially with the rotation axis, and the signal light focused by the hologram is reflected by the reflection d. 2. The hologram scanner according to claim 1, wherein the hologram scanner passes through the inside of the rotating member and forms an image on a photodetector installed outside the rotating member on the center line of rotation. 3. The signal light focused by the hologram is once reflected by a fixed mirror such as a plane mirror, concave mirror, or parabolic mirror fixed outside the rotating member, and then passed through the rotating member again to be detected by a photodetector outside the rotating member. The hologram scanner according to claim 1, wherein the hologram scanner forms an image.