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WO2004097715A1 - Systeme optique - Google Patents

Systeme optique Download PDF

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Publication number
WO2004097715A1
WO2004097715A1 PCT/DK2004/000293 DK2004000293W WO2004097715A1 WO 2004097715 A1 WO2004097715 A1 WO 2004097715A1 DK 2004000293 W DK2004000293 W DK 2004000293W WO 2004097715 A1 WO2004097715 A1 WO 2004097715A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical system
image
aperture
lens
aspheric
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/DK2004/000293
Other languages
English (en)
Inventor
René Skov HANSEN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Novo Nordisk AS
Original Assignee
Novo Nordisk AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Novo Nordisk AS filed Critical Novo Nordisk AS
Priority to EP04730200A priority Critical patent/EP1634218A1/fr
Publication of WO2004097715A1 publication Critical patent/WO2004097715A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10821—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum further details of bar or optical code scanning devices
    • G06K7/10831—Arrangement of optical elements, e.g. lenses, mirrors, prisms
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/10—Scanning systems
    • G02B26/101—Scanning systems with both horizontal and vertical deflecting means, e.g. raster or XY scanners
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10712—Fixed beam scanning
    • G06K7/10722—Photodetector array or CCD scanning
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10792—Special measures in relation to the object to be scanned
    • G06K7/10801—Multidistance reading
    • G06K7/10811—Focalisation
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/14—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation using light without selection of wavelength, e.g. sensing reflected white light
    • G06K7/1404—Methods for optical code recognition
    • G06K7/1408—Methods for optical code recognition the method being specifically adapted for the type of code
    • G06K7/1417—2D bar codes

Definitions

  • the invention relates to an optical system for imaging an object on an image sensor, said system having an optical axis extending through an aperture and through image-forming means that comprise an aspheric light-beam- refracting surface.
  • the invention is directed in particular, but not exclusively, to reading of information on vials that may contain eg insulin.
  • Such indication is to contain information regarding the contents of the container, their expiry date, production date, batch number, etc.
  • the code readers are constructed primarily on the basis of two principles. Firstly, a principle in which a scanning collimated beam that has a small cross section is used for lighting the code point by point, which is typically accomplished by a laser beam being reflected in mirrors with cyclical movements in combination with a photodetector to determine the intensity of reflected light from a lighted point on the code.
  • the prior art optics for image sensors intended for code readers have a work range that extends from no less than 30 to typically 500 mm focal length.
  • a very important aspect of the invention is that the matrix code can be read by means of an optical system that is so compact that it can be built integrally with eg a drug administration device for dispensing insulin.
  • the information on the vial can be used for calculations within the drug administration device, and albeit the invention also lends itself for use in connection with conventional bar codes, their information density is typically too small for efficiency advantages to be obtained in connection with a calculation unit in the drug administration device.
  • the invention will now be described in connection with two-dimensional matrix coding and two problems arise from this; on the one hand the problem of positioning the matrix code correctly relative to the optical system and on the other hand the problem of having the matrix code imaged correctly on the sensor so as to ensure that only little distortion in lack of focus occurs even in case the focal length is desired to be considerably less than 30 mm.
  • the problem is due to the overall limited depth of field and increasing optical distortion in case of small focal lengths. Deficient focusing in combination with the position on the code being depicted on the image sensor with a nonlinear positional transformation makes the decoding algorithm unstable or entirely prevents decoding. On top of this problem there is the cylindrical surface of the carpule that makes demands to the tolerance of the system towards precisely depth of field and nonlinear positional transformation. The major problem is that beams coming from the extreme corners of the object have to travel a considerably longer path from the image plane than beams coming from the centre of the matrix code.
  • GB 2 287 551 , US 5 305 147, and US 5 311 364 teach optical systems with aspheric lenses wherein short focal length is aimed at. These prior art systems are very complex and expensive since they aim at large collimating apertures and low distortion in general.
  • the object of the invention is to provide an optical system of the above- described kind, wherein it is accomplished to have very little distortion in terms of lack of focus by means of inexpensive and operationally reliable optical elements.
  • the system comprises an aperture configured and located such in relation to an aspheric light-beam-refracting surface that beams of light from two image points having dissimilar distances from the optical axis are deflected by mutually different surface portions of the aspheric surface.
  • aspheric surfaces refers to non-planar and non-spherical surfaces that according to the invention enable compensation of optical distortion by means of the disclosed use of aperture size and position.
  • the aspheres can be bicurvatured, for example a paraboloide, as well as predominantly elongated and single-curvatured, for example a cylinder.
  • the asphere can be used as the only focussing element in the system, or it can be used as a predominantly corrective element in combination with other optical elements.
  • the diameter of the aperture is such that beams coming from the edge of the object are refracted by points on the surface of the asphere, not comprising the apex of the asphere.
  • the opening size of the aperture to object and image planes, respectively; is dimensioned such that the part of the aspheric surface that refracts beams from the edge of the object does not coincide with that part of the aspheric surface that refracts beams coming from the centre of the object.
  • an aspheric lens element is used, but the principle of the invention also comprises use of an aspheric mirror.
  • Light-beam refraction surfaces refer to refractive and reflective optical elements with properties that can be described by geometrical optics (ray tracing models). Light-beam refracting surfaces furthermore refer to optical elements that are partially or fully based on diffraction phenomena.
  • the aspheric lens is injection-moulded and the aperture is circular.
  • the aperture may be elongate, thereby allowing that the light beams in one single dimension, ie planes that contain the optical axis, can be refracted by both the centre and the edge area of the lens.
  • the optical error will not be particularly large due to the matrix code usually being single-curved and not double-curved.
  • an elongate aperture opening will be used in combination with an elongate lens, whose surface has an aspheric curvature seen transversally to the longitudinal direction of the lens.
  • the system comprises a moulded housing provided with an aperture that is integral with the housing and comprises fixation means for the image-forming means.
  • fixation means for the image-forming means Several lenses may be provided in the housing that preferably comprises fixation means for one or more light sources or light conductors. Since the housing may also comprise fixation means for the image sensor, an optical system is obtained, wherein it is possible to accomplish, by inexpensive means, an accurate positioning of simple optical elements configured such that an approximately, distortion-free imaging of a curved object can be accomplished on a plane object sensor, while simultaneously the optical distance between object and the image sensor is very small, eg less than 30 mm.
  • the small distortion that still occurs with the optical system according to the invention can be further reduced by means of image-correcting circuits that are known per se and receive digital image data from an image sensor.
  • the correcting circuit can be based on a digital polynomium function.
  • the invention is especially useful when incorporated in a doser for drug administration or a BGM due to its very compact and reliable design.
  • FIG 1 shows the technical principle according to the invention
  • Figure 2 shows a two-dimensional matrix code known per se
  • Figure 3 is a sectional view through an optical sensor according to the invention.
  • Figure 4 is an exploded view of the embodiment shown in Figure 3.
  • a part of the surface 1 of a cylindrical vial is shown, which is provided with a label 2 (see Figure 2). Furthermore an optical sensor or camera chip 3, a lens 4 and an aperture 5 are shown. From the figure it will clearly appear that the path to be travelled by a light beam from point A to point B is longer that the path to be travelled by a light beam from point C to point D.
  • the deviation in path lengths can for example reach 12% when triangulation is used on the optical system.
  • the effect of the present invention is that the optical system can be made very compact and if a length of the optics of eg 12 mm is imagined, said 12% will correspond to 1.4 mm, which is approaching the theoretical depth of field for such system when the aperture opening is 0.5 mm.
  • the depth of field of eg 1.4 mm is to suffice for said effects with the path length plus all uncertainties in the mechanical joints. This means that, in practice, it is not possible to construct an optical system with lengths of eg 12 mm of a sufficiently high quality by means of prior art constructional principles.
  • the aperture opening is very important to the depth of field, once it is less than approximately 0.5 mm, the undesired diffraction phenomena increase and the light intensity of the sensor drops to levels that are useless to relevant lights sources and sensors.
  • an aspheric image-forming element such as the lens 4 is combined with a small aperture, eg 0.5 mm.
  • the aperture and its location in relation to the lens 4 is to be configured such that the beam path is accomplished that is shown in Figure 1 , from where it will appear that light beams from the point A is refracted through such portions of the aspheric surface that do not overlap the portions of the aspheric surface where the light beams from C to D are refracted. Therefore the two said areas of the lens surface may be configured such that they each take into account the different focal distances to the respective parts of the label 2.
  • r is the radial coordinator in a coordinate system having its origin in the apex of the lens.
  • Figure 2 shows an example of a two-dimensional matrix code 6 known per se and comprising a number of dots, eg a dark dot 7 and a light dot 8.
  • matrix codes are known, see eg US patent No. 5,126,542, wherein the light and dark dots, respectively, represent 0 and 1 , respectively, in digital information.
  • Such two-dimensional matrix code has considerably higher information density than can be obtained in connection with a bar code, and albeit the invention also lends itself for use in connection with the bar code, the advantages of the invention are particularly obvious when a two- dimensional matrix code is used since, by imaging of such code imaging problems will occur when the matrix code is located on a round surface, eg a label on an insulin ampoule.
  • Figure 3 is a sectional view through a preferred embodiment of the invention.
  • the figure shows a vial 11 provided with a label 12 and supported in a seat 28.
  • the information on the label is read by means of an optical system mounted on an electrical circuit board PCB 14.
  • On the circuit board light diodes 15 and 16 are also mounted as well as an image sensor 17.
  • the opticaj system is also shown in Figure 4.
  • Reference numeral 18 is used to designate a light-conductor component for receiving light from the light diodes 15 and 16.
  • the light-conductor component has polished surfaces, eg shown by 19-21 , such that the light leaves through a dull surface 22, whereby homogenous and diffusely distributed light is emitted towards the label 12.
  • a thin, transparent, protective barrier 23 is provided which allows for cleaning of the optical system.
  • a part 24 of the light-conductor component 18 is configured as an aspheric lens 24 and by 25 an aperture is shown; see the aperture 5 shown in Figure 1. Furthermore a non-transparent shield 26 is provided to ensure that no intrusive light is allowed to enter the image sensor that is only to receive light from the label via the lens 24.
  • the components just mentioned are surrounded by a housing 27 which will be explained in more detail with Figure 4.
  • Figure 4 is an exploded view of the embodiment shown in Figure 3.
  • the housing 27 is a separate injection-moulded component containing a not shown, thin transverse beam 29 in which the aperture 25 is configured.
  • the light-conducting component 18 comprises, as mentioned above, the lens 24, and as will appear from the above explanation, it is important according to the invention that the lens is arranged very well-defined in relation to the aperture 25. In the embodiment shown, this is accomplished by means of guide faces 30, 31 on the component 18, which faces fit into corresponding recesses in the moulded component 27, as will appear clearly from Figure 4. In this manner the lens 24 and the aperture 25 are positioned perfectly accurately in relation to each other.
  • the positioning of the image sensor 17 in relation to the optical elements can be made in a conventional way, e.g. by cooperating projections and depression on the two parts to be assembled.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Theoretical Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

La présente invention concerne un système optique qui permet de former une image sur un capteur d'images, lequel système comprend un axe optique qui s'étend à travers une ouverture et à travers des moyens de formation d'image comportant une surface asphérique de réfraction de faisceau lumineux. Selon l'invention, un élément asphérique de formation d'image, tel que la lentille (4), est combiné à une petite ouverture (5). L'ouverture (5), et son emplacement par rapport à la lentille (4), doit être configurée de telle manière que la trajectoire du faisceau s'effectue tel qu'illustré à la figure 1, d'où il apparaît que les faisceaux lumineux en provenance du point A sont réfractés à travers des parties de la surface asphérique qui ne chevauchent pas les parties de la surface asphérique où les faisceaux lumineux de C à D sont réfractés. Les deux zones précitées de la surface de la lentille peuvent par conséquent être configurées de telle manière que chacune d'elles tient compte des distances focales différentes qui les séparent des parties respectives de l'étiquette (2).
PCT/DK2004/000293 2003-05-01 2004-04-29 Systeme optique Ceased WO2004097715A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP04730200A EP1634218A1 (fr) 2003-05-01 2004-04-29 Systeme optique

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DKPA200300651 2003-05-01
DKPA200300651 2003-05-01
US47167203P 2003-05-19 2003-05-19
US60/471,672 2003-05-19

Publications (1)

Publication Number Publication Date
WO2004097715A1 true WO2004097715A1 (fr) 2004-11-11

Family

ID=33420361

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DK2004/000293 Ceased WO2004097715A1 (fr) 2003-05-01 2004-04-29 Systeme optique

Country Status (2)

Country Link
EP (1) EP1634218A1 (fr)
WO (1) WO2004097715A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007039100A1 (fr) * 2005-09-21 2007-04-12 Novartis Ag Systeme d'inspection optique
US7614545B2 (en) 2003-03-24 2009-11-10 Novo Nordisk A/S Electronic marking of a medication cartridge
US7621456B2 (en) 2000-08-10 2009-11-24 Novo Nordisk A/S Support for a cartridge for transferring an electronically readable item of information from the cartridge to an electronic circuit
US8197449B2 (en) 2005-05-10 2012-06-12 Novo Nordisk A/S Injection device comprising an optical sensor
US8994382B2 (en) 2006-04-12 2015-03-31 Novo Nordisk A/S Absolute position determination of movably mounted member in medication delivery device
US9950117B2 (en) 2009-02-13 2018-04-24 Novo Nordisk A/S Medical device and cartridge

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5291008A (en) * 1992-01-10 1994-03-01 Welch Allyn, Inc. Optical assembly and apparatus employing same using an aspherical lens and an aperture stop
US5331143A (en) * 1992-08-28 1994-07-19 Symbol Technologies, Inc. Optical scanner using an axicon and an aperture to aspherically form the scanning beam
US5596454A (en) * 1994-10-28 1997-01-21 The National Registry, Inc. Uneven surface image transfer apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5291008A (en) * 1992-01-10 1994-03-01 Welch Allyn, Inc. Optical assembly and apparatus employing same using an aspherical lens and an aperture stop
US5331143A (en) * 1992-08-28 1994-07-19 Symbol Technologies, Inc. Optical scanner using an axicon and an aperture to aspherically form the scanning beam
US5596454A (en) * 1994-10-28 1997-01-21 The National Registry, Inc. Uneven surface image transfer apparatus

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7621456B2 (en) 2000-08-10 2009-11-24 Novo Nordisk A/S Support for a cartridge for transferring an electronically readable item of information from the cartridge to an electronic circuit
US7614545B2 (en) 2003-03-24 2009-11-10 Novo Nordisk A/S Electronic marking of a medication cartridge
US8197449B2 (en) 2005-05-10 2012-06-12 Novo Nordisk A/S Injection device comprising an optical sensor
US8771238B2 (en) 2005-05-10 2014-07-08 Novo Nordisk A/S Injection device comprising an optical sensor
US9522238B2 (en) 2005-05-10 2016-12-20 Novo Nordisk A/S Injection device comprising an optical sensor
WO2007039100A1 (fr) * 2005-09-21 2007-04-12 Novartis Ag Systeme d'inspection optique
US8994382B2 (en) 2006-04-12 2015-03-31 Novo Nordisk A/S Absolute position determination of movably mounted member in medication delivery device
US9950117B2 (en) 2009-02-13 2018-04-24 Novo Nordisk A/S Medical device and cartridge

Also Published As

Publication number Publication date
EP1634218A1 (fr) 2006-03-15

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