Laser photoelectric analytical balance

Abstract

The invention provides a laser photoelectric analytical balance, which is characterized in that two quartz glass trips with silver mirrors coated on the surfaces are parallel up and down; one laser transmitter transmits laser beams to the lower surface of the upper glass strip of a deformation element at a fixed inclination angle and the laser beams are reflected multiple times between the two mirror surfaces of the upper and lower glass strips; a light spot position sensor is arranged at the falling point of the laser beams after multiple times of reflection and is connected in an electrical bridge as a variable resistor; the two output ends of the electrical bridge are connected at the input interface of a measuring and amplifying circuit in a current electrical balance. When the pressure on the upper glass strip changes, deformation change leads to corresponding change of the angles of the reflected laser beams, after multiple times of reflection, accumulation and reinforcement, the light spot position sensor outputs corresponding resistance and the resistance is processed by the measuring and amplifying circuit, thereby realizing weighing. The analytical balance has the advantages of good linearity, high sensitivity and electromagnetic interference resistance.

Description

technical field [0001] The invention relates to a weighing appliance, which is an analytical balance. Background technique [0002] The sensor of the electronic analytical balance adopts a strain sensor, which is a single crystal silicon substrate pasted on an alloy aluminum or alloy steel strip, and circuitous P-type or N-type semiconductor resistance strips are diffused on the substrate and connected to form a bridge. Under the action of pressure, the alloy aluminum or alloy steel strip deforms, which drives the deformation of the single crystal silicon substrate. According to the piezoresistive effect of the semiconductor, the resistivity of the resistance strip changes, causing a change in the resistance value. After being introduced into the measurement circuit, its The change of the output voltage reflects the change of the pressure, so as to achieve the purpose of weighing the mass of the object. [0003] Since the single crystal silicon substrate is pasted on the al...

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Problems solved by technology

[0003] Since the single crystal silicon substrate is pasted on the alloy aluminum or alloy steel bar with an adhesive, the adhesive layer has a certain toughness and has a buffering effect. In addition, the internal structure of the alloy aluminum or alloy steel bar is complex and not a uniform crystal structure. It is difficult to guarantee the linearity of the deformation

Therefore, the resolution of the existing strain sensor is not high, and the accuracy of the electronic analytical balance is not high enough.

[0004] In addition, since the circuitous semiconductor resistance strips are exposed to the environmental electromagnetic field, they are easily disturbed, and the accuracy of weighing cannot be guaranteed.

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