Bar code reading apparatus with multifocal length optical system
AssigneeNippondenso Co., Ltd.
InventorsTakeshi Miwa, Takeshi Matsushima
Life of this patent
Estimating the term…
Abstract
A bar code reader is provided which comprises a photodetector responsive to light reflected from a bar code to provide a signal indicative of bar code information, a lens assembly including a near range focus lens and a long range focus lens having different focal lengths, and a liquid crystal filter assembly. The liquid crystal assembly includes a near range focus filter and a long range focus filter and selectively allows only light emerging from one of the near range focus lens and the long range focus lens to reach the photodetector according to the distance to the bar code.
Claims15
An optical information reading apparatus comprising:
- a single photodetector sensor responsive to light reflected from an object including encoded preselected optical information, said single photodetector sensor providing a signal indicative of said optical information;
- a lens assembly including a plurality of lenses arranged in parallel and having respective focal lengths which are different, each of said plurality of lenses focusing light reflected from said object on said single photodetector sensor;
- reflected light selecting means for selectively allowing only light emerging from one of said plurality of lenses of said lens assembly to reach said single photodetector sensor while blocking light emerging from others of said plurality of lenses of said lens assembly from reaching said single photodetector sensor;
- and
- optical information reading means for reading said optical information encoded on said object based on said signal indicative of said optical information.
An optical information reading apparatus comprising:
- a single photodetector sensor responsive to a light beam reflected from an object including encoded preselected optical information, said single photodetector sensor providing a signal indicative of said optical information;
- a parallel lens assembly including a near range focus lens and a long range focus lens each focusing said light beam reflected from said object on said single photodetector sensor, said near range focus lens having a near range focal length, and said long range focus lens having a long range focal length longer than said near range focal length;
- reflected light selecting means, switchable between a first operational mode and a second operational mode, for selecting one of a first light beam passing through said near range focus lens of said parallel lens assembly and a second light beam passing through said long range focus lens of said lens assembly, said first operational mode allowing said first light beam emerging from said near range focus lens to reach said single photodetector sensor while blocking said second light beam emerging from said long range focus lens, said second operational mode allowing said second light beam emerging from said long range focus lens to reach said single photodetector sensor while blocking said first light beam emerging from said near range focus lens;
- and
- optical information reading means for reading said optical information encoded on said object based on said signal indicative of said optical information.
Dependencies are inferred from the claim text.