Optical information reader and method of manufacturing the optical information reader

Patent metadata

Field	Value
Publication number	US-2020393645-A1
Application number	US-201816634840-A
Country	US
Kind code	A1
Filing date	Jul 25, 2018
Priority date	Jul 28, 2017
Publication date	Dec 17, 2020
Grant date	—

Abstract

An optical information reader includes an imaging lens and a lens retainer retaining the imaging lens and assembled, in this state, into the holder. The lens retainer includes a flange bottom surface and end faces as a reference surface that is parallel to an optical axis of the imaging lens. The holder includes a top surface and edge faces as a guide surface. The guide surface is brought into surface contact with the flange bottom surface and the end faces when the lens retainer is assembled into the holder, and is brought into slidable contact with the flange bottom surface and the end faces when the lens retainer is moved along the optical axis. Thus, influence of one-sided blur is minimized in terms of variation in resolution which is measured when obtaining an optimal focus position by changing relative positions of the area sensor and the imaging lens.

First claim

1 . An optical information reader including an area sensor that receives reflected light from an information code via an imaging lens, and optically reading the information code, based on a signal outputted from the area sensor, comprising:
a holder to which the area sensor is fixed; and a lens retainer that retains the imaging lens and is assembled, in this state, into the holder, the lens retainer including a reference surface that is parallel to an optical axis of the imaging lens, wherein the holder is provided with a guide surface with which the reference surface is brought into surface contact and against which the reference surface is brought into slidable contact, the surface contact being achieved when the lens retainer is assembled into the holder so that light passing through the imaging lens produces an image on the area sensor, the slidable contact being achieved when the lens retainer is moved along the optical axis.

2 . The optical information reader according to claim 1 , wherein
the area sensor has a rectangular light-receiving surface; a position where one-sided blur occurs is confirmed for each imaging lens, the one-sided blur causing deterioration in performance in terms of a produced mage in a portion of a field of view via the imaging lens; and the lens retainer retains the imaging lens so that the portion of the field of view causing the one-sided blur is located outside the light-receiving surface near a long side thereof.

3 . The optical information reader according to claim 1 , wherein
the reference surface includes a planar first reference surface and planar second reference surfaces with which the first reference surface intersects; and the guide surface includes a planar first guide surface with which the first reference surface is brought into slidable contact, and planar second guide surfaces with which the second reference surfaces are respectively brought into slidable contact.

4 . The optical information reader according to claim 3 , wherein
the lens retainer includes a flange; the flange has a flat surface on an imaging lens side, the flat surface including at least a portion serving as the first reference surface; and the holder is formed so that a portion of the lens retainer is housed in the holder via an opening provided to a flat surface of the holder, the portion of the lens being located closer to the imaging lens than to the flange when assembled, the flat surface having at least a portion serving as the first guide surface.

5 . The optical information reader according to claim 4 , wherein the flange is formed so as to have a flat surface on an imaging lens side, the flat surface covering the opening during the slidable contact.

6 . The optical information reader according to claim 3 , wherein
the first reference surface and the second reference surfaces are formed using a projection provided to an outer surface of the lens retainer; and the first guide surface and the second guide surfaces are formed using a recess provided to the holder.

7 . The optical information reader according to claim 3 , wherein
the first reference surface and the second reference surfaces are formed using a recess provided to an outer surface of the lens retainer; and the first guide surface and the second guide surfaces are formed using a projection provided to the holder.

8 . The optical information reader according to claim 3 , wherein the lens retainer is formed so that at least a portion of an outer peripheral surface of the lens retainer serves as the first reference surface and the second reference surfaces, the outer peripheral surface having a polygonal cross section as viewed perpendicularly to a plane through which the optical axis passes.

9 . The optical information reader according to claim 1 , wherein the lens retainer is formed so that at least a portion of an outer peripheral surface of the lens retainer serves as the reference surface.

10 . The optical information reader according to claim 1 , wherein the lens retainer is provided with engagement portions used when the lens retainer is moved relative to the holder along the optical axis.

11 . A method of manufacturing an optical information reader for manufacturing the optical information reader
wherein the optical information reader including an area sensor that receives reflected light from an information code via an imaging lens, and optically reading the information code, based on a signal outputted from the area sensor, comprising: a holder to which the area sensor is fixed; and a lens retainer that retains the imaging lens and is assembled, in this state, into the holder, the lens retainer including a reference surface that is parallel to an optical axis of the imaging lens, wherein the holder is provided with a guide surface with which the reference surface is brought into surface contact and against which the reference surface is brought into slidable contact, the surface contact being achieved when the lens retainer is assembled into the holder so that light passing through the imaging lens produces an image on the area sensor, the slidable contact being achieved when the lens retainer is moved along the optical axis, the method comprising steps of: assembling the lens retainer retaining the imaging lens into the holder, to which the area sensor is fixed, so that the reference surface is brought into surface contact with the guide surface; assembling an arm movable along the optical axis to the lens retainer; sequentially measuring resolution of the area sensor, while the arm is moved in a direction along the optical axis so that the reference surfaces is brought into slidable contact with the guide surface; fixing the lens retainer, with the arm being assembled thereto, to the holder at a peak position where measured resolution is regarded to be a peak; and detaching the arm from the lens retainer.

12 . The method of manufacturing an optical information reader according to claim 11 , wherein, in the step of fixing the lens retainer to the holder, the peak position is obtained while the arm is moved in a primary direction along the optical axis, the arm is then moved over the peak position in a secondary direction, which is opposite to the primary direction, along the optical axis, and the arm is then moved again in the primary direction toward the peak position to fix the lens retainer to the holder at the peak position.

13 . The optical information reader according to claim 11 , wherein, in the step of sequentially measuring resolution, a movement amount of the arm when resolution of a predetermined value or more is measured is set so as to be smaller than a movement amount of the arm when resolution of less than the predetermined value is measured.

14 . An optical information reader including an area sensor that receives reflected light from an information code at a rectangular light-receiving surface, and optically reading the information code, based on a signal outputted from the area sensor, comprising:
a first illuminant emitting visible light and a second illuminant emitting invisible light toward an imaging field of view of the area sensor, the visible light and the invisible light serving as illumination light, wherein the first illuminant and the second illuminant are arranged in line along a short-side direction of the light-receiving surface.

15 . The optical information reader according to claim 14 , wherein the first illuminant and the second illuminant are arranged so that a light-receiving axis of the area sensor is located between the first illuminant and the se

Assignees

• Denso Wave Inc

Inventors

• Ito Makoto
• Sugiura Ryo

Classifications

• G06K7/10544

  by scanning of the records by radiation in the optical part of the electromagnetic spectrum · CPC title

• G02B7/02

  for lenses {(supports for magnifying lenses G02B25/002)} · CPC title

• G06K7/10821

  further details of bar or optical code scanning devices · CPC title

• G02B7/023

  permitting adjustment · CPC title

• G06K7/10831

  Arrangement of optical elements, e.g. lenses, mirrors, prisms (optical elements per se G02B) · CPC title