Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – In combination with or also constituting light responsive...
Reexamination Certificate
2002-07-02
2003-10-28
Tran, Minh Loan (Department: 2825)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
In combination with or also constituting light responsive...
C257S080000, C257S081000, C257S084000, C257S098000, C257S099000, C257S432000
Reexamination Certificate
active
06639248
ABSTRACT:
CROSS REFERENCES TO RELATED APPLICATIONS
The present document is based on Japanese Priority Document JP 2001-204406, filed in the Japanese Patent Office on Jul. 5, 2001, the entire contents of which being incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light emitting and receiving device structure suitably employed in an optical apparatus for bar code reading, and more particularly to improvement techniques which enable miniaturization and lightweight of such device structure to be achieved by adjusting arrangement of a light emitting element and a light receiving element.
2. Description of the Related Art
Recently, a great many stores, shops, factories and the like put bar codes on their goods and products for sales control and production management. The bar codes, each representing digital information, are read by optical scanning. In general, by irradiating beams of light to the bar codes and subjecting the intensity of reflected beams of light to photoelectric conversion, this type of bar code provides information from a combination of detected signals therefrom.
Namely, as shown by a conceptual representation in
FIG. 5
, a beam of light from a light emitting element
1
is focused through an iris of a light projection lens
3
, and the beam of light thus obtained is reflected off a mirror
7
of a scan mirror
5
to irradiate a bar code pattern
9
which is a target of irradiation. Since the beam of light is irradiated over the entire area of the bar code pattern
9
, the mirror
7
is oscillated. The oscillation occurs as follows: by fitting a magnet
11
, which is attached to the mirror
7
, into a drive coil
13
, for example, positive and negative current is applied to the drive coil
13
at a constant period, then the magnet
11
is attracted to and repelled from the drive coil
13
, thus causing the mirror
7
to oscillate relative to an oscillating fulcrum point
15
as its fulcrum.
On the other hand, the beam of light irradiated on the surface of the bar code pattern
9
, despite undergoing irregular reflection, returns to the mirror
7
again through changes in the quantity of light due to the black and white of the bar code pattern. Then, the beam of light reflected there is condensed by a condenser lens
17
, changes in the quantity of light being electrically converted by a light receiving element
19
and outputted. It should be noted that for the sake of increasing the reading accuracy, a band pass filter (BPF) is set up in front of the light receiving element
19
to prevent admitting unnecessary beams of light other than those beams of the light emitting optical frequency.
A light emitting and receiving device for bar code reading shown in
FIG. 6
is available as a conventional apparatus which is constructed in accordance with the above-mentioned bar code reading method. The light emitting and receiving device is, as illustrated, configured by a light emitting assembly A incorporating a light emitting element
1
and a light projection lens
3
in a housing
25
and a light receiving assembly B incorporating a light receiving element
19
and a light receiving lens
17
, and a BPF
21
in a housing
27
. Both assemblies are mounted on a substrate
29
.
Electrical connections in each of the housing
25
and the housing
27
are performed by wire bonding or other methods, and the mirror
7
of the scan mirror
5
is so arranged as to enable oscillation relative to the oscillation fulcrum point
15
. Further, these light emitting assembly A, light receiving assembly B, and scan mirror
5
are accommodated in a frame not illustrated to form a light emitting and receiving device for bar code reading.
Nevertheless, since the light emitting and receiving device for bar code reading comprises the light emitting assembly with the light emitting element and the light projection lens accommodated in a casing separately from the light receiving assembly B with the light receiving element and the light receiving lens accommodated in another casing, there are a large number of parts. In addition, because the light emitting element and the light receiving element need to be juxtaposed facing a target of irradiation, a gap occurs between the packages to necessitate a large installation space, setting limits to achieving miniaturization and light weight of the entire light emitting and receiving device.
On the other hand, miniaturization may be conceivably accomplished by juxtaposing and incorporating the light emitting element and the light receiving element in a single package, while, on the other hand, an area due to package duplication can be dispensed with by constructing an integral, one-piece package, but the need to secure the spaces for mounting the light emitting element and the light receiving element on the same plane yet remains, thus making it impossible to accomplish sufficient miniaturization.
Further, in a case of juxtaposing the light emitting element and the light receiving element on the same plane, the optical axis of an emitted beam of light cannot be placed in close proximity to the optical axis of a return beam of light, so that the light projection lens is disposed on the outside face of the light receiving lens, contributing to enlarging a space occupied by the optical system—another detriment to achieving miniaturization and light weight of the light emitting and receiving device.
SUMMARY OF THE INVENTION
The present invention is directed to solving these drawbacks, and provides a light emitting and receiving device structure which can place an optical axis of an emitted beam of light in close proximity to an optical axis of a return beam of light, thereby accomplishing the miniaturization and light weight of the light emitting and receiving device.
A light emitting and receiving device structure according to a first aspect of the present invention comprises a cylindrical package having a bottom with an opening on one end and the other end closed, and a pedestal member concentric with a center line of the package and protrudingly disposed on a bottom plate in the package. In the device structure, the light receiving element is secured to a front end surface of the pedestal member and the light emitting element is secured to a side face of the pedestal member, so that the light emitting element and the light receiving element are both accommodated in the same package.
In the light emitting and receiving device structure, each surface (the front end surface and the side face) of the cubic pedestal member protrudingly disposed on the bottom plate of the package is utilized for a space of mounting each element; for example, as compared with a structure of juxtaposing a light emitting element and a light receiving element on the bottom plate, the present arrangement can provide high-density accommodation by making an outer diameter of the package small. Namely, the miniaturization of the package becomes possible.
Further, through this structure of element arrangement in this manner, it is possible to place an optical axis of an emitted beam of light in close proximity to an optical axis of a return beam of light, enabling a light projection lens to be easily placed on a region of the light receiving lens, whereby a medium is jointly used (made possible by a one-piece light projection and receiving lens with the formation of a light projection lens element on a part of the light receiving lens) to enable an optical system to be made lightweight.
A light emitting and receiving device structure according to a second aspect of the present invention comprises a strip of light emitting element of having a light emitting unit on an end surface and irradiating a beam of light emitted from the light emitting unit to a target of irradiation; a strip of light receiving element of having a light receiving face on a surface thereof and receiving a return beam of light from the target of irradiation on the light receiving face; a cylindrical package having a bottom with an opening on one
Aizawa Hidekuni
Matsuura Tamiaki
Shinzawa Shigeru
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