CN202522516U

CN202522516U - Optical transmissivity test device

Info

Publication number: CN202522516U
Application number: CN201220085172XU
Authority: CN
Inventors: 冯科; 李劲松
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2012-03-07
Filing date: 2012-03-07
Publication date: 2012-11-07
Anticipated expiration: 2022-03-07

Abstract

The utility model relates to an optical transmissivity test device, which comprises an LED light source, a microscope objective, an aperture diaphragm, a beam expander, plate glass to be tested, a condensing mirror, a photoelectric diode, a signal processing circuit, an A/D (Analog/Digital) converter and a microcomputer processing system. The LED light source, the microscope objective, the aperture diaphragm, the beam expander, the plate glass to be tested, the condensing mirror and the photoelectric diode are arranged on the optical axis of beam propagation of the light source in sequence from left to right; a light beam emitted from the LED light source is received by the microscope objective and then converged, the aperture diaphragm is arranged at the converging position of the light beam and used for blocking light, the light beam passing through the aperture diaphragm is subjected to beam-expanding and collimation through the beam expander, the collimated light vertically passes through a sample to be tested and is converged on a photosensitive surface of the photoelectric diode by the condensing mirror, an optical signal is converted into an electric signal by the photoelectric diode, the output electric signal is processed by the signal processing circuit and is subjected to analog/digital conversion by the A/D converter, and the converted digital signal is input into the microcomputer processing system and is automatically processed and then a transmissivity value is displayed.

Description

A kind of device for testing optical transmittance

Technical field

The utility model relates to a kind of device for testing optical transmittance, belongs to the photometry field of measuring technique.

Background technology

As far as optical system, transmitance is a very important techniques index, indicates that optical instrument transmits the power of a certain band of light radiation energy, usually it is defined as the ratio of emergent light flux and incident flux.The imaging signal to noise ratio (S/N ratio) height of its affects optical system is the important indicator of system capacity transmission.

Transmissivity of optical system generally can be divided into spectral transmittance and integration transmitance.Spectral transmittance is exactly that the monochromatic transmitance of different-waveband is measured, and is usually used in being operated in the system under the monochromatic light situation; Corresponding with it integration transmitance is promptly measured the polychromatic light transmitance that is combined by monochromatic light, is applied in the most visible light system.

Main transmission measurement method has monochromatic light road method of testing and double light path method of testing.Monochromatic light road method of testing is the ratio of the empty measured value after sample is placed on the measured value that obtains in the optical system for testing and removes, as the transmitance of sample.And double light path test rule is that light beam is divided into two-beam through spectroscope, leads up to sample, is to be actual measurement, and another road is to be that sky is surveyed, again with the transmitance value of the two ratio as sample through sample.

Monochromatic light road method mainly contains integrating sphere method and large tracts of land uniform source of light method.And the signal of integrating sphere method receive to adopt is large tracts of land, highly sensitive receiver, and this is a kind of method of traditional measurement of Lens visible light wave range transmitance, the system that also can be used to test infrared band.The shortcoming of this method is that the integrating sphere volume is comparatively huge, makes relatively difficulty of integrating sphere, and requires detector to have sufficiently high sensitivity.The consistance of intensity of light source when traditional monochromatic light road method of testing can't guarantee empty survey and actual measurement, it is bigger to detect error, and obstructed ovennodulation, can't avoid the interference of ground unrest, and experimental precision is difficult to guarantee.

The double light path method of testing is to the improvement on monochromatic light road and perfect, and characteristics are that measuring accuracy is higher, and test speed is fast, and shortcoming is that its device is comparatively complicated, and the adjusting of light path is difficulty very.

The prior art patent close " shadow mask transmission measurement sensor " with the utility model, the patent No. 200420079825.9, what this patent adopted is monochromatic light road method of testing; Advantage is the semiconductor laser that has adopted collimation higher, and energy is more concentrated, good directionality; Whole system structure of device is simple, and cost is low, does not consider the light stability problem of light source when still testing; Empty survey and actual measurement has individual mistiming, change need consideration for light intensity in poor during this period of time; In addition, do not take to suppress the measure that bias light disturbs yet, can increase the difficulty of signal Processing like this.

The utility model content

In order to overcome the defective that prior art exists; The utility model provide a kind of easily, device for testing optical transmittance cheaply, its purpose is when simplifying light path, to adopt internal modulation; Be that the power supply modulation is modulated the light signal that sends indirectly; Suppress the interference of bias light, the light intensity that adopts stabilized voltage supply to come stabilized light source finally improves measuring accuracy.

The technical matters that the utility model will solve is: provide a kind of easily, device for testing optical transmittance cheaply.The technical scheme of technical solution problem, as shown in Figure 1: as to comprise led light source 1, microcobjective 2, aperture diaphragm 3, beam expanding lens 4, sheet glass to be measured 5, condenser 6, photodiode 7, signal processing circuit 8, A/D converter 9, microprocessor system 10; As shown in Figure 2, the stabilized voltage supply that relates in the device all adopts circuit shown in Figure 2; As shown in Figure 3, the power supply of led light source 1 is the pulse power, adopts 555 timers and photoelectric coupled device to form.

On the optical axis of led light source 1 beam propagation, from left to right settle led light source 1, microcobjective 2, aperture diaphragm 3, beam expanding lens 4, sheet glass to be measured 5, condenser 6, photodiode 7 successively; The divergent beams that led light source 1 is launched are received by microcobjective 2; Assemble then, settle aperture diaphragm 3 to block light in its convergence place, the light beam through aperture diaphragm 3 carries out beam-expanding collimation with beam expanding lens 4 again; Light behind the collimation is vertically through sheet glass 5 to be measured; Converged on the photosurface of photodiode 7 by condenser 6, photodiode output links to each other with the input of signal processing circuit 8 again, after electric signal process signal processing circuit 8 amplification filtering; Output terminal connects the signal input interface of A/D converter 9; Carry out data acquisition and analog to digital conversion then, the output terminal of A/D converter 9 links to each other with the microcomputer input interface, digital signal is input to handles in the microprocessor system 10 and demonstration transmitance value.

Because the light stability of led light source is higher, adopt led light source can increase the measuring accuracy of device, the power supply of light source adopts pulsed modulation; Promptly, can suppress bias light effectively and disturb, because the microcobjective focal length is short the modulation of output light signal; Can shorten the length overall of optical system, make system compacter, for the detection reception of light signal; Photodiode has advantages such as response speed is fast, frequency response characteristic good, and noise is little.

The good effect of the utility model: adopt power supply to modulate the interference that suppresses bias light to light signal, guaranteed measuring accuracy, greatly simplified light path, reduced installation cost.

Description of drawings

Fig. 1 is the schematic diagram of device of the utility model embodiment;

Fig. 2 is the utility model embodiment+15V and-15V DC-stabilized circuit figure.

Fig. 3 is the pulse power supply circuit figure of the led light source of the utility model embodiment.

The practical implementation instance

The utility model embodiment implements by apparatus structure shown in Figure 1, and the led light source 1 among Fig. 1 adopts green-light source, and the peak wavelength of spectral radiance is 546nm; Power is 1W; Microcobjective 2 focal distance f 1=17mm among Fig. 1, the beam expanding lens 4 among Fig. 1, condenser 6 focus on and are respectively f2=100mm, f3=150mm; Sheet glass to be measured 5 among Fig. 1 adopts the dull and stereotyped UV mirror of bore D=50mm, and the photodiode 7 among Fig. 1 adopts the photodiode of the model BPW21R of Daheng's photoelectricity.Its peak response wavelength is 560nm, and the A/D converter 9 among Fig. 1 adopts the K7512 data collecting card.

D.C. regulated power supply among the utility model embodiment all adopts power circuit shown in Figure 2, and the voltage stabilizer among Fig. 2 adopts 79 serial three terminal regulators.

The power supply of the led light source among the utility model embodiment adopts pulse power supply circuit as shown in Figure 3, adopts 555 timers to produce pulse waveform among Fig. 3, the break-make that the photoelectrical coupler of employing model 6N137 comes control circuit.

In when experiment, led light source 1 is placed before the microcobjective 2, light is converged get into aperture diaphragm 3.Adjustment beam expanding lens 4 positions are positioned on the object space focal plane of beam expanding lens 4 aperture diaphragm 3, like this through expanding the light that bundle obtains a branch of parallel outgoing.Mixed up under the coaxial situation in system, the position of adjustment photodiode 7 focuses on the photosurface of photodiode 7 light of being assembled by condenser 6, and light path is promptly built and finished.Energized afterwards, led light source 1 sends the light signal of alternation through the modulation of pulse power supply, the luminous flux when associated electrical signals when measuring no sample and the subsequent treatment of carrying out obtain the sky survey.Between beam expanding lens 4 and condenser 6, adding sheet glass 5 to be measured afterwards and regulating light path makes between sample and optical axis vertical.Owing to added sheet glass 5 to be measured; Sample meeting antireflection part light; The light of this part reflection can reflect by beam expanding lens 4 inverse imagings to aperture diaphragm 3 places, can whether be positioned at aperture diaphragm 3 centers through the picture point that reflects and is benchmark and adjust the position of sheet glass 5 to be measured and make it vertical with optical axis, can measure after adjusting; And carry out the luminous flux of subsequent treatment when obtaining surveying, in microprocessor system 10, do and be divided by automatically and show the transmitance value.In order to improve precision, average as a result of with sampled measurements repeatedly.

The foregoing description does not limit the utility model in any form, and all employings are equal to the technical scheme that mode obtained of replacement or equivalent transformation, all drops on the protection domain of the utility model.

Claims

1. device for testing optical transmittance; Comprise led light source, microcobjective, aperture diaphragm, beam expanding lens, sheet glass to be measured, condenser, photodiode, signal processing circuit, A/D converter, microprocessor system; It is characterized in that on the optical axis of led light source beam propagation, from left to right settle led light source, microcobjective, aperture diaphragm, beam expanding lens, sheet glass to be measured, condenser, photodiode successively; The divergent beams that led light source is launched are received by microcobjective; Assemble then, settle aperture diaphragm to block light in its convergence place, the light beam through aperture diaphragm carries out beam-expanding collimation with beam expanding lens again; Light behind the collimation is vertically through sheet glass to be measured; Converged on the photosurface of photodiode by condenser, photodiode output links to each other with the input of signal processing circuit again, after the electric signal process signal processing circuit amplification filtering; Output terminal connects the signal input interface of A/D converter; Carry out data acquisition and analog to digital conversion then, the output terminal of A/D converter links to each other with the microcomputer input interface, digital signal is input to handles in the microprocessor system and demonstration transmitance value.

2. device for testing optical transmittance according to claim 1, the power supply that it is characterized in that led light source is the pulse power.