Handheld laser short-distance measurement instrument

Abstract

The invention relates to the technical field of photoelectricity, in particular to a handheld laser short-distance measurement instrument. The handheld laser short-distance measurement instrument comprises a laser distance measurement instrument main body, wherein the laser distance measurement instrument main body comprises a measurement optical system; the measurement optical system comprises a laser emitter; a first polarizing beam-splitting plate used for transmitting P light and filtering S light is arranged at the emission end of the laser emitter; polarized light emitted by the first polarizing beam-splitting plate faces to a polarizing beam-splitting mirror, a reflective direction of the polarizing beam-splitting mirror faces to a light outlet, and a light-emitting direction of the light outlet faces to a target object; a second polarizing beam-splitting plate used for transmitting P light and filtering S light is arranged behind the polarizing beam-splitting mirror; a receiving-end photoelectric part is arranged behind the second polarizing beam-splitting plate; the light outlet, the polarizing beam-splitting mirror, the second polarizing beam-splitting plate and the receiving-end photoelectric part are arranged in sequence from front to rear; a connecting line of the light outlet and the receiving-end photoelectric part forms an included angle of 45 degrees with the reflective surface of the polarizing beam-splitting mirror. The handheld laser short-distance measurement instrument has the characteristics that the short-distance target object is measured more accurately, errors are smaller, the operation is convenient, and a serious nonlinear problem caused by diffuse reflection of the target object is solved.

Description

technical field [0001] The invention relates to the field of optoelectronic technology, in particular to a laser range finder. Background technique [0002] The handheld laser range finder is an instrument that uses laser to accurately measure the distance of the target. When the laser rangefinder is working, it emits a very thin beam of laser rangefinder light to the target. The photoelectric element receives the laser beam reflected by the target. distance. Traditional handheld laser rangefinders mostly use off-axis optical systems to receive laser reflection echoes. When the target appears far away (greater than 10 meters), the returned light is basically parallel light, which is focused on the photoelectric beam through an aspheric receiving lens. on an avalanche diode (APD), where the photosensitive surface of the APD is 0.23 mm in diameter (see attached figure 1 ). However, since the focal length of the system is not variable, when the rangefinder measures a target...

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Problems solved by technology

However, since the focal length of the system is not variable, when the rangefinder measures a target at a short distance (especially 2 to 5 meters), the following problems will occur: the light spot emitted by the laser cannot be directly received by the APD (see the attached figure 2 ), and relying on free reflection of light will bring more serious nonlinearity, so auxiliary optical path design is needed to make APD receive good signal light

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