Hyperchannel measuring refractive indexes of liquid instrument
Technical field
The utility model relates to a kind of device of measuring liquid refractivity.
Background technology
People are by to the measurement of liquid refractivity, can understand the concentration, composition, proportion of fluid to be measured etc., and be widely used in fields such as food, medicine, biology, petrochemical industry.The method of existing survey liquid refractivity has visual method and with two kinds in digital liquid refractivity instrument.Visual method influences because of being subjected to the sight equation subjective factor, and error is bigger; Digital liquid refractivity instrument is to measure with charge-coupled device (CCD) or PSD position transducer.Charge-coupled device (CCD) detects the light intensity catastrophe point on the curve of light distribution, determines detected liquid refractive index.Use charge-coupled device (CCD) refractometer measuring accuracy height, scope is big, reading is directly perceived, and can realize that real-time online detects, but because charge-coupled device (CCD) costs an arm and a leg and pixel size is bigger, so this digital liquid refractivity instrument cost height, volume is big.Use the PSD position transducer to measure the centre of gravity place of hot spot, utilize the centre of gravity place of hot spot and the corresponding relation of refractive index to determine liquid refractive index.Though this digital liquid refractivity instrument physical dimension is little, precision is lower, and range is short.Because charge-coupled device (CCD) and PSD position transducer all can only transmit the light intensity signal on the one dimension direction, so can not use on multichannel measuring instrument.In addition, the physical instability of high refractive index liquid, these two kinds of single channel measuring refractive indexes of liquid instrument are very difficult to the high index of refraction calibration.
Summary of the invention
In view of above-mentioned, the purpose of this utility model provide a kind of high precision, wide-range, inexpensive, volume is little, portable hyperchannel measuring refractive indexes of liquid instrument.
The key of the utility model technical solution is: utilize hot spot edge of image position on the face array CMOS image sensor measuring prism, because the marginal position and the refractive index of light spot image have clear and definite corresponding relation, so can be used to determine liquid refractive index.
Hyperchannel measuring refractive indexes of liquid instrument comprises several light sources, the polygon prism that alternately is bonded together and constitutes successively by different prism of several refractive indexes and shading dividing plate, the sample cell of dress fluid to be measured, many slit plates, poly-lens, color filter, face array CMOS image sensor and signal conditioning package and display, the number of prisms that the refractive index of above-mentioned formation polygon prism is different is identical with the quantity of light source, be distributed with prism on many slit plates and stitch one to one, poly-lens by with many slit plates on seam one to one lens and putting constitute, sample cell is installed on the polygon prism, bottom land communicates with polygon prism, the light beam that each light source sends is respectively through oblique prism and the fluid to be measured interface of being mapped to of the different prism of refractive index, the critical angle total reflection light that forms passes each lens that sewing up on many slit plates is mapped to poly-lens respectively, each light beam enters color filter respectively after lens converge, by difference entering surface array CMOS image sensor after the color filter colour filter, the marginal position digital signal input of the light spot image of face array CMOS image sensor output is used for the marginal position conversion of signals of light spot image is become the signal conditioning package of refractive index value, the output terminal of signal conditioning package links to each other with display, shows the liquid refractivity value by display.
Light source, the prism of hyperchannel measuring refractive indexes of liquid instrument, be distributed in seam on many slit plates and the quantity of lens is consistent, each passage has a light source, a prism, a seam and lens.Can measure different liquid refractivity intervals by the prism of different refractivity, satisfy the requirement of wide-range.Make the total reflection light of water on the lowest refractive index prism measure the passage calibration, satisfied requirement the high index of refraction calibration to all.The range that each passage is corresponding certain, the user can be according to range needs selector channel quantity.
Above-mentioned face array CMOS image sensor is a two-dimensional device, can transmit the marginal position digital signal of the light spot image on the two-dimensional directional, can select the data of entire image, the part line data that also can only select image converts the processing of refractive index value to by signal conditioning package, obtains the refractive index of fluid to be measured.
Above-mentioned signal conditioning package can adopt commercially available MSP430 microprocessor.
Because the hyperchannel measuring refractive indexes of liquid instrument that the utility model provides adopts the different polygon prism of refractive index, therefore can be used for respectively measuring the different liquid refractivity of refractive index, satisfied the requirement of wide-range.And the face array CMOS image sensor is that a kind of price is low, volume is little, the face array photoelectric sensor spare of pixel little (5.6um), makes hyperchannel liquid measure instrument have high precision, wide-range, inexpensive, advantage such as volume is little, be easy to carry.
Description of drawings
Fig. 1 is a kind of concrete structure synoptic diagram of the present utility model;
Fig. 2 is the sectional view of the biprism of Fig. 1;
Fig. 3 is the circuit diagram that signal conditioning package is connected with other parts.
Embodiment
With binary channels measuring refractive indexes of liquid instrument shown in Figure 1 is example.
Binary channels measuring refractive indexes of liquid instrument comprises two light sources 1, by the different prism 3.1 of two refractive indexes be positioned at the biprism 3 (referring to Fig. 2) that the shading dividing plates 3.2 in the middle of these two prisms are bonded together and constitute, the sample cell 4 of dress fluid to be measured, double slit plate 5, double lens 6, color filter 7, face array CMOS image sensor 8 and signal conditioning package 9 and display 10, two seams 5.1 on the double slit plate 5 are corresponding with prism 3.1, double lens 6 is by two lens and put and constitute, sample cell 4 is installed on the biprism 3, bottom land communicates with biprism, fluid to be measured places in the sample cell 4, two light sources can be with two light emitting diodes, the two-way light that it sends is respectively through two prisms, 3.1 oblique prism and the fluid to be measured interfaces of being mapped to, formed critical angle total reflection light passes sewing up of double slit plate respectively and is mapped to double lens 6, after converging, lens enter color filter 7, by difference entering surface array CMOS image sensor 8 after color filter 7 colour filters, the marginal position digital signal input information treating apparatus 9 of the light spot image of face array CMOS image sensor output, convert corresponding refractive index value by its marginal position digital signal that will reflect the light spot image of fluid to be measured refractive index to through calculating, and be presented on the display 10.
Usually, for improving measuring accuracy, when measuring liquid refractivity, consider the influence of environment temperature, can adopt temperature sensor, in schematic structure, also be provided with temperature sensor 11, temperature sensor can be arranged on the shelf that prism 3 is installed,, by it liquid refractivity value be carried out temperature compensation and calculate the temperature signal input information treating apparatus of temperature sensor output.
In the circuit of Fig. 3, the clock signal of cmos image sensor is provided by MSP430, and the clock signal of cmos image sensor output is connected with the I/O mouth of MSP430 respectively with data-signal, can be read in the data of cmos image sensor output by MSP430.The display that uses in this example is a LCD, and the COM end of this display links to each other with the COM end of MSP430, and other pin links to each other with each S pin of MSP430.The temperature sensor that uses in the system is a thermistor, uses a reference resistance to contact with it, changes and obtains temperature value by the magnitude of voltage between two resistance being carried out AD.
The utility model can be widely used in fields such as food, medicine, biology, petrochemical industry, and pol value, concentration value, proportion, the one-tenth of measuring liquid grade.