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Patent Issued for Optical Detection Device, Optical Device, Optical Information Reading Device, and Light Source Fixing Method

March 5, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventor Yamanouchi, Masayoshi (Saitma, JP), filed on February 12, 2013, was published online on February 18, 2014.

The assignee for this patent, patent number 8654425, is Optoelectronics Co., Ltd. (JP).

Reporters obtained the following quote from the background information supplied by the inventors: "The invention relates to an optical detection device including a photodetector element and outputting an electrical signal according to a light amount received by the photodetector element, an optical device including such an optical detection device on a substrate, an optical device including an irradiating means irradiating a target object with a light, and an optical information reading device including such optical devices and reading information indicated by a code symbol in which modules having different light reflectivity from surroundings are arranged. Further, the invention also relates to a light source fixing method for fixing a light source unit to the above-described optical device.

"A code symbol called a bar code or a two-dimensional code is an image formed of modules of black bars (or simply 'bars') with low light reflectivity and white bars (or spaces) with high light reflectivity.

"In general, a method is well known which represents information related to an item by such a code symbol, prints or attaches this code symbol to the item, and reads this code symbol with an optical information reading device. As a field of use, a POS (Point Of Sales) system disposed in a retail store such as a supermarket or the like is a representative example, but besides that, the field ranges broadly over distribution of goods, mail service, event place management, medical service, chemical inspection, and so on.

"Then, to classify roughly, as the optical information reading device, there are laser code scanners using laser and area sensor scanners using a camera which uses a CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), or the like. Among them, as compared to the area sensor scanners, the laser code scanners have a long history and technologies built up, and hence are highly reliable.

"In such a laser code scanner, there is mounted a small light scanning module which scans a reading target object with a light flux (laser light) using a semiconductor laser element as a light source, and decodes information from a reflected light thereof. Then, for this light scanning module, a method to rotate a polygon mirror and a scanning mirror method to vibrate one mirror are known as methods for deflecting a laser light for scanning.

"For example, PTL1 describes a bar code reader which emits a light from a light emitting element such as a semiconductor laser and reflects the light by one surface of the polygon mirror toward the reading target object. PTL2 describes an optical information reading device in which a laser beam emitted from a light emitting unit is reflected by a vibrating mirror, which vibrates in a seesaw manner, toward the reading target object.

"In these devices, for illuminating the reading target object with a large amount of light fluxes, the former device is equipped with a polygon mirror having many reflecting surfaces, and the latter device vibrates a mirror with one surface. The amount of light fluxes illuminating the reading target object relates also to accuracy when decoding the code symbol, and illuminating with a large amount of light fluxes enables good decoding."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventor's summary information for this patent: "Now, in addition to the decoding accuracy as described above, size reduction and thickness reduction of the light scanning module performing scanning of a light beam and detection of a reflected light, which is to be mounted in the optical information reading device, are major challenges. It is because the light scanning module is mounted not only in, as is conventional, a dedicated device for reading information such as a handheld scanner, but also scenes of mounting the light scanning module further additionally in multifunction electronic devices such as handy terminals and smart phones are increasing.

"The light scanning module using the technology described in PTL2 was recognized as the world smallest module when it is released, but further size reduction is demanded nowadays.

"Then, a problem that arises in an attempted to carry out this size reduction is the optical function of the module. Specifically, when the module is reduced in size, unless it is structured such that an optical flux having sufficient intensity moves forward and backward inside, the intensity of the light flux for scanning the reading target object becomes weak, and this leads to reduction in decoding accuracy.

"The present invention is made in view of such a background, and an object thereof is to enable size reduction of an optical device which scans a target object with a light beam and detects a reflected light thereof, and an optical information reading device using a module having such a function.

"To achieve the object, an embodiment of the invention may include an optical detection device including a photodetector element provided on a first surface of a substrate and a planar output electrode provided on a second surface opposite to the first surface of the substrate for outputting an electrical signal according to a light amount received by the photodetector element, further including: a cutout portion provided on a third surface of the substrate that is different from the first surface and the second surface, the cutout portion being in contact with the output electrode provided on the second surface; and an electrode connected to the output electrode and provided on an inner surface of the cutout portion.

"In such an optical detection device, it is preferable that the third surface is a surface substantially perpendicular to the first surface.

"Further, an optical device of the invention includes: a circuit substrate on which a connection electrode is provided; and any of the above described optical detection devices disposed such that the cutout portion opposes the connection electrode on the circuit substrate to be connected to the output electrode and that the first surface is substantially perpendicular to a surface on which the connection electrode of the circuit substrate is provided, wherein the output electrode and the connection electrode on the circuit substrate are connected electrically by a conductive material filled in the cutout portion.

"In such an optical device according, it is preferable that the device further includes: an irradiating means for irradiating a reading target object with a light; and an optical member for allowing a reflected light from the reading target object to be incident on the photodetector element provided on the substrate of the optical detection device, wherein an optical path of the reflected light from being incident on the optical member to being incident on the photodetector element is substantially parallel to a surface on which the connection electrode of the circuit substrate is provided.

"Further, another optical device of the invention includes an irradiating means for irradiating a target object with a light, wherein the irradiating means includes a light source unit including a laser light source outputting a laser light and a collimator lens passing the laser light outputted by the laser light source, wherein the optical device further includes a pedestal for disposing the light source unit such that the laser light source outputs the laser light in a direction along an optical path which passes through an optical axis of the collimator lens, and wherein the light source unit is fixed by a first fixing means to the pedestal to be movable only in a direction along the optical path, and further fixed by a second fixing means different from the first fixing means to the pedestal to be unmovable in the direction along the optical path.

"In such an optical device, it is preferable that the pedestal has a trench in a direction along the optical path, and at least a part of the light source unit is inserted in the trench provided in the pedestal and is restricted in movement to a direction different from the trench.

"Further, it is preferable that the light source unit and the pedestal respectively include a pair of projecting portions at positions where the projecting portions on the light source unit side and the projecting portions on the pedestal side are in contact with each other via a flat surface when the light source unit is disposed on the pedestal, the projecting portions having a substantially constant width in a direction along the optical path, and the first fixing means is a clip having elasticity which fixes the projecting portions on the light source unit side and the projecting portions on the pedestal side by sandwiching them in a state of being in contact with each other.

"Furthermore, it is preferable that a gap is provided in an exterior for inserting, from a direction perpendicular to the optical path, the clip sandwiching the projecting portions on the light source unit side and the projecting portions on the pedestal side.

"Besides, in the above optical device, it is preferable that the irradiating means is a means for irradiating a target object with a laser light outputted from the laser light source via the collimator lens and an aperture having a slit-shaped opening, and the collimator lens is disposed before the aperture in the optical path of the laser beam, and has a same shape as the opening of the aperture and a size such that the laser beam which passed through the collimator lens reaches the aperture with a size larger than the opening.

"Further, it is preferable that the collimator lens disposed before the aperture is a lens having a power of a cylindrical lens on one surface and having a power of a collimator lens on another surface, and makes the laser beam outputted from the laser light source form an elliptic beam spot.

"Besides, in the above optical device, it is preferable that the irradiating means and a vibrating mirror for deflecting the laser light outputted by the laser light source of the irradiating means to scan the target object are provided in an exterior, and an opening is provided in one surface of the exterior, and a rotation shaft of the vibrating mirror and a bearing for rotatably fixing the vibrating mirror to the rotation shaft are disposed to penetrate the opening.

"Further, it is preferable that a cover covering the rotation shaft and the bearing which penetrate the opening is provided on the one surface of the exterior.

"Furthermore, it is preferable that the one surface of the exterior is formed of a circuit substrate, and the circuit substrate is fixed by a fastener to a case forming another surface of the exterior.

"Further, an optical information reading device of the invention includes any of the above optical devices and reads information indicated by a code symbol in which modules having different light reflectivity from surroundings are arranged.

"Besides, a light source fixing method of the invention is a method for fixing, when an optical device including an irradiating means for irradiating a target object with a light is produced, a light source unit including a laser light source outputting a laser light as a light source of the irradiating means to a case of the optical device, the method executing sequentially: a first step of preparing the case of the optical device, to which a collimator lens is fixed, including a pedestal for disposing the light source unit such that the laser light source outputs the laser light in substantially parallel to an optical path which passes through an optical axis of the collimator lens; a second step of fixing the light source unit to the pedestal to be movable only in a direction along the optical path, by a first fixing means; a third step of moving the light source unit in a direction along the optical path to adjust a position thereof to a position where the laser light outputted by the laser light source becomes a parallel light by the collimator lens; and a fourth step of fixing the light source unit to the pedestal to be unmovable in the direction along the optical path, by a second fixing means different from the first fixing means.

"In such a light source fixing method, it is preferable that the pedestal has a trench in a direction along the optical path, and the second step includes a step of inserting at least a part of the light source unit in the trench provided in the pedestal.

"Further, it is preferable that the light source unit and the pedestal respectively include a pair of projecting portions at positions where the projecting portions on the light source unit side and the projecting portions on the pedestal side are in contact with each other via a flat surface when the light source unit is disposed on the pedestal, the projecting portions having a substantially constant width in a direction along the optical path, and in the second step, the projecting portion on the light source unit side and the projecting portion on the pedestal side are fixed with a clip having elasticity and inserted from a direction perpendicular to the optical path by sandwiching the projecting portions in a state of being in contact with each other.

"By using an optical detection device, an optical device, or a light source fixing method according to the invention, a module which scans a target object with a light beam and detects a reflected light thereof can be reduced in size. Further, by an optical information reading device of the invention, a device can be reduced in size by utilizing the optical detection device or an optical device as described above."

For more information, see this patent: Yamanouchi, Masayoshi. Optical Detection Device, Optical Device, Optical Information Reading Device, and Light Source Fixing Method. U.S. Patent Number 8654425, filed February 12, 2013, and published online on February 18, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=52&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2592&f=G&l=50&co1=AND&d=PTXT&s1=20140218.PD.&OS=ISD/20140218&RS=ISD/20140218

Keywords for this news article include: Semiconductor, Optoelectronics Co. Ltd..

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Source: Electronics Newsweekly


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