Opposite irradiation type photoelectric sensor and target detection system

Abstract

The embodiment of the invention relates to an opposite irradiation type photoelectric sensor and a target detection system. The opposite irradiation type photoelectric sensor comprises a light projector and light receiver, wherein the light projector comprises a light emitting element, a first lens, a first baffle plate, the light emitting element emits light, the first lens converts the light emitted by the light emitting element into parallel light, the first baffle plate is located between the light emitting element and the first lens, the first baffle plate is provided with a first throughhole, the center of the first through hole is overlapped with the focus of the first lens, and the field of view formed by the light emitted from the light emitting element is controlled through thefirst through hole. According to the embodiment of the invention, a sufficient-light light spot of a required shape can be obtained, a small installation distance between the opposite irradiation typephotoelectric sensors can be met, and the consistency of optical axes can also be ensured.

Description

technical field [0001] The invention relates to a photoelectric sensor, in particular to a through-beam photoelectric sensor and a target detection system using the through-beam photoelectric sensor. Background technique [0002] In the prior art, the focal point of the lens in the light projector in the through-beam photoelectric sensor is usually set at the light source, for example, the LED chip, such as figure 1 shown. However, since the metal wire connection part (W / B, Wire Bonding) of the wafer on the LED chip does not emit light, the amount of light projected into the center of the light spot in the light receiver will not be sufficient, and there will be W / B shadow effects, such as figure 2 As shown, it is easy to misjudgment when using the through-beam photoelectric sensor to detect whether there is a target. [0003] In order to solve the above problems, the LED chip can be moved to the direction of the lens in the light projector to become a defocused state, su...

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Problems solved by technology

[0005] However, at present, due to the very narrow installation space in the thin gate, the installation bracket that can adjust the angle of the light receiver cannot be installed; and, if the design simply reduces the field of view, the optical axis of the light emitter and light receiver will be different during installation. Alignment is very difficult

[0006] In addition, when installing the light emitter and light receiver, it is necessary to align the optical axis of the light receiver with the optical axis of the light emitter, but due to the influence of LED component deviation and / or installation deviation and / or printed circuit board (PWB) assembly deviation, etc. The optical axis is shifted, so that the center of the spot is displaced relative to the mechanical axis, and the optical receiver may have a certain offset in the direction perpendicular to the optical axis (that is, the optical receiver has a translation distance relative to the optical axis), which will affect the parallelism. mobile features

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