Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2002-05-23
2004-07-27
Lee, Michael G. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S454000, C235S462350, C235S462320
Reexamination Certificate
active
06766957
ABSTRACT:
CROSS REFERENCES TO RELATED APPLICATIONS
The present invention claims priority to its priority documents No. 2001-156508 and No. 2001-184725 filed in the Japanese Patent Office on May 25, 2001 and Jun. 19, 2001, respectively, the entire contents of which are expressly incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical device for bar-code reading and a method for manufacturing thereof, in particular to those capable of improving the individual degrees of freedom in design and positioning accuracy of a light projection lens and a light receiving lens in an integrated constitution and also to a light projection/receiving package for bar-code reading, and in particular for improving the downsizing of the package through minimizing an area for mounting a light emitting element and a receiving element.
2. Description of the Related Art
Many recent shops and factories practice sales management of commodities or production management of products by attaching thereto bar codes indicating digital information of the products and by reading such information through optical scanning thereof. In a general procedure using such kinds of bar codes, light is irradiated to a bar code and reflected light therefrom is processed by photo-electric conversion, depending on the intensity of the reflected light, to thereby decode the information based on a combined pattern of detected signals.
More specifically, as schematically shown in
FIG. 19
, a light projection lens
3
focuses light emitted from a light emitting element
1
, and thus focused light is irradiated to a bar code
9
after being reflected off a mirror
7
of a scan mirror
5
. Mirror
7
is swung so as to irradiate the entire area of bar code
9
. The swinging of mirror
7
is based on attraction and repulsion of a magnet
11
attached to mirror
7
to or from a drive coil
13
into which magnet
11
is inserted, where drive coil
13
is applied with positive and negative currents inverting at a predetermined cycle to thereby swing mirror
7
around a fulcrum of swinging
15
.
The light irradiated on a surface of bar code
9
returns back to mirror
7
with an intensity variation caused by a black-and-white pattern of bar code
9
while being affected by some irregular reflection. A condensing lens
17
then focuses the light reflected there, and a light receiving element
19
electrically converts the intensity variation to produce an output. Light receiving element
19
is provided on a front surface with a band-pass filter (BPF)
21
for improving accuracy in the reading, to thereby successfully prevent unnecessary light having a frequency other than the emission frequency from being caught.
There has been provided an optical device for bar-code reading, as shown in
FIG. 20
which materializes such reading systems. As illustrated in
FIG. 20
, the device comprises a light emitting assembly A having a light emitting element
1
and a light projection lens
3
housed in a casing
25
, and a light receiving assembly B having a light receiving element
19
, a light receiving lens
17
and a BPF
21
housed in a casing
27
, both assemblies being mounted on a substrate
29
. Electrical connections within individual casings
25
and
27
are accomplished through wire bonding or the like. Mirror
7
of scan mirror
5
is arranged so as to allow swinging around the fulcrum of swinging
15
. Light emitting assembly A, light receiving assembly B and scan mirror
5
are housed in a housing not shown, to thereby form an optical device for bar-code reading.
The foregoing optical device for bar-code reading however, requires a large mounting space and can attain only a limited range of downsizing since light emitting assembly A having light emitting element
1
and the light projection lens
3
housed in casing
25
, and light receiving assembly B having, light receiving element
19
and light receiving lens
17
in casing
27
are separately composed.
As measures for solving such non-conformity, there is known a “bar-code reader” as disclosed in Japanese Patent Application Publication No. Hei 7-93454, in which two lens portions are integrated into one transparent lens to thereby downsize a device as a whole, and a “bar-code reading device” as disclosed in Japanese Patent Application Publication No. Hei 11-15910, in which an irradiation lens and an imaging lens are formed using a transparent resin material in an integrated manner to thereby reduce the number of optical parts and save labor for assembly.
While these devices were successful in achieving a certain degree of space saving, it has not been allowable to choose different media as being optimized for the light emitting characteristics and the light receiving characteristics, since the light projection lens portion and the light receiving lens portion are molded in an integrated manner within a single kind of transparent resin used as a medium. It also has been difficult to compose either lens as a compound lens or to provide different coatings for the individual lenses, which has limited the design of such lenses. Still another problem resides in that this kind of integrated mold lens cannot allow movement of either lens once the other lens is properly positioned and fixed, which inhibits precise positioning by finely adjusting positions of both lenses on the light emitting side and the light receiving side.
An electro-optical reading device, as disclosed in, Japanese Patent Application Publication No. Hei 11-326805, is such that it has a semiconductor laser chip (light emitting element) and a photo detector (receiving element) mounted side by side on one surface of a printed circuit board, where all of which are covered with a mold resin member. To the mold resin member, a lens, a prism and an opening are molded in an integrated manner so as to allow the laser light from the semiconductor laser chip to be focused, bent in the optical path thereof and emitted, and, further, having a concave mirror for focusing the returned light towards a photodetector, to thereby achieve downsizing and weight reduction. The device, however, inevitably has a large printed circuit board due to the planar arrangement of the semiconductor laser chip and photo-detector side by side on one surface of the printed circuit board, so that downsizing cannot be attained
The present invention was proposed considering the foregoing situation and provides an optical device for barcode reading capable of improving the degree of freedom in design of the component lenses so as to allow free positional adjustment of such lenses while ensuring a small size and light weight of the device per se and a method for manufacturing thereof.
Furthermore, the present invention also was proposed considering the foregoing situation and provides a light projection/receiving package in which keeping an area sufficient for the mounting of either one of a light emitting element and a receiving element enables mounting of the other element to thereby achieve downsizing and weight reduction of the package.
As has been detailed in the above, since the light projection/receiving package according to the second aspect of the present invention is composed so that a light emitting element and a light receiving element are mounted back to back on front and rear planes of a single die pad, it is not necessary to keep both areas for mounting the light emitting element and the light receiving element on one plane (on the same plane) of the die pad. Accordingly, it will be sufficient to use a die pad affording a mounting area for either element requiring a larger mounting area, and this intrinsically allows mounting of the other element on the opposite plane. That is, only a small die pad affording a mounting area for either the light emitting element or the light receiving element allows the mounting of both. This successfully results in downsizing and weight reduction of the
SUMMARY OF THE INVENTION
An optical device for bar-code reading according to a first aspect
Aizawa Hidekuni
Matsuura Tamiaki
Shinzawa Shigeru
Kananen Ronald P.
Lee Michael G.
Nguyen Kimberly
Rader & Fishman & Grauer, PLLC
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