CN2593172Y - Spectrometer for measuring grating corner by linear array CCD - Google Patents

Abstract

The utility model belongs to a spectrum instrument. The utility model is composed of a grating reflective mirror, a line light source, a linear array CCD, a binary data collection card and a computer, wherein, a plane grating is provided with a reflective mirror, a light source is arranged on the same horizontal plane with the image sensitive surface of the linear array CCD and the middle line of the reflective mirror, and parallel light rays and the horizontal line form a finite angle; the linear array CCD is utilized to measure directly the rotation angle of the grating rather than measure indirectly the rotation angle of the grating, and the spectrum wave length of the spectrum surface of a spectrograph can be calculated by the measured rotation angle of the grating. In the way, the additional error caused by a rotation mechanism and a rotary measuring mechanism of the ordinary spectrograph is overcome. Therefore, the spectrograph is high in precision and speed during spectrum measurement.

Description

Line array CCD is measured the grating corner and is surveyed spectrometer

Technical field

The utility model belongs to measurement and analysis instrument, more specifically says so to belong to spectral instrument.

Background technology

Existing various grating spectrum instrument, the normal sine that adopts stepper motor and precision lead screw to constitute is retouched mechanism and is driven grating rotating, and determines spectral wavelength on the spectrum face with the rotational angle of the method measurement grating of the parameter (pitch and corner) of the rotation step number of counting stepper motor and precision lead screw.In addition, the grating chi of installation is also arranged on leading screw or hold micrometer such as grid chi and move system, calculate the corner of grating again, measure the wavelength of spectrum face spectrum by the amount of spin of measuring sine sweep mechanism.Preceding a kind of method must be provided with the starting point of scanning mechanism, and must at first make sine sweep mechanism return zero (getting back to the starting point of scanning mechanism) after start.Spectrometer is after start like this, and machine will return Z-operation (whether tube shutter is in the precalculated position) earlier, and then scans step by step on the predetermined spectral position.Obviously, this spectrometer is time-consuming, and since zero resetting device return zero precision, the precision of precision lead screw, precision lead screw cooperates the backlash that causes with nut, stepper motor is lost and is gone on foot and belt pulley factor such as skid all will be introduced the spectral measurement error.Though a kind of method was returned the shortcoming that zero defective and belt pulley, stepper motor are lost step etc. before a kind of method in back had overcome,, it still can't resolve the problem that leading screw cooperates with nut.

Summary of the invention

In order to overcome above-mentioned shortcoming, we adopt line array CCD directly to measure the corner of grating planar, and the spectral detection device that can be applicable to various spectrometers is with performances such as the measuring accuracy that improves spectrometer and speed.

The technology that line array CCD is measured grating corner survey spectrometer is achieved in that

It is made up of grating reflective mirror, line source, line array CCD, binaryzation data collecting card and computing machine; Plane grating is provided with reflective mirror, and light source is arranged on the image sensing surface of line array CCD and the center line of reflective mirror to become in the same horizontal plane, and parallel rays and horizontal line have a certain degree.

The grating reflective mirror is the plane mirror that is installed on the plane grating; The minute surface of plane mirror is parallel with grating planar.Line source is for sending the light source of rectangle directional light.

This line array CCD is measured grating corner survey spectrometer and is applicable to various spectrometers.

Utilize principle that line array CCD directly measures the grating corner as shown in Figure 1, figure cathetus AB is the minute surface that is fixed on the plane mirror on the grating.A branch of rectangle directional light 1 is incident upon on the level crossing center of rotation O, receive reflected light in the reflected light direction with a line array CCD 2 or one group of line array CCD 2, shown in figure cathetus MP, the positional information of the center line of rectangle directional light on the CCD image planes and the corner of grating, promptly the blaze wavelength with grating has relation one to one.

If the direct of travel of rectangle directional light and the angle of horizontal direction are α, the initial position of plane mirror is AB, and its normal is OP, like this, the incident angle and the emergence angle of rectangle directional light are α, the long distance that equals the CCD image planes to plane mirror center of rotation O of OP.When AB turned over an angle θ, normal forwarded the OQ position to by OP, and incident angle and the emergence angle of this moment become β.There is following relation at angle γ and the θ angle of emergent ray OM, ON before and after rotating:

γ＝2α-2β＝2(α-β)＝2θ (1)

When survey spectrum CCD detected the zero level principal maximum at the receiving screen P place of Fig. 1, the detected rectangle directional light of angle measurement CCD position of center line was exactly the M point.Known OP and α, and MP=OPtg α are so P point position also can be determined.If angle measurement CCD detects PN=x, ∠ NOP=arctg (x/OP) then, and $\mathrm{\θ}=\frac{1}{2}\mathrm{\γ}=\frac{1}{2}(\mathrm{\α}-\∠\mathrm{NOP})=\frac{1}{2}(\mathrm{\α}-\mathrm{arctg}\frac{x}{\mathrm{OP}})---\left(2\right)$

With θ substitution (2), finally try to achieve blaze of grating wavelength for shown in (3) formula:

D is a grating constant in the formula, and is both angle between grating and two catoptrons of textural constant of spectrometer, and OP is the distance of plane mirror to line array CCD, and α is an initial angle as shown in Figure 1, more than these 4 parameters be constant.By starting condition, when initial angle was α, the directional light position of center line that line array CCD records was xo, and α is α=arctg (xo/OP).This shows that blaze of grating wavelength X only has definite funtcional relationship with the detected x value of angle measurement CCD, and irrelevant with other parameters.I.e. explanation can detect the wavelength of spectrometer spectrum face with angle measurement CCD, and measuring accuracy is relevant with the precision that the line array CCD location moves x.

Utilize line array CCD directly to measure the corner of grating rather than measure the corner of grating indirectly, calculate spectrometer spectrum face spectral wavelength by the grating corner of measuring.Like this, overcome the additive error that the normal optical spectrometer is brought because of rotating mechanism and amount of spin measuring mechanism.The precision that the spectrometer survey is composed is higher, speed is faster.

Compare with the wavelength measurement mechanism of normal optical spectrometer, utilizing line array CCD to measure grating corner survey spectrometer has following characteristics:

1, through angle measurement CCD with after surveying spectrum CCD combined calibrating, starting point M is just determined by unique, does not have the probabilistic problem of starting point, has eliminated the survey spectrum error that rotating mechanism and amount of spin measuring mechanism are introduced.

Line array CCD be used for dimensional measurement be very effectively, proven technique.Because it is strong that line array CCD itself has high resolving power, high sensitivity, location of pixels information, the characteristic of compact conformation and self-scanning thereof, so this measuring method often need not to dispose the complicated mechanical rotating mechanism, thereby has reduced error source, make measurement more convenient, accurate.

3. adopt the spectrometer of this patent need before each the use, not carry out " return-to-zero " operation, and directly detect current blaze wavelength, saved " return-to-zero " running time, promptly made things convenient for use, accelerated measuring speed again.

Description of drawings

Fig. 1: line array CCD is measured the schematic diagram that the grating corner is surveyed spectrometer;

Fig. 2: line array CCD is measured the grating corner and is surveyed the spectrometer structural drawing;

Fig. 3: the connection diagram of reflective mirror and plane grating.

Embodiment

The utility model is described in further detail below in conjunction with accompanying drawing and principle:

Utilize line array CCD to measure structure that the grating corner surveys spectrometer as shown in Figure 2.Fig. 2 is made of grating reflective mirror, line source, line array CCD, binaryzation data collecting card and computing machine etc., grating reflective mirror 5 wherein is for being installed in the plane mirror on the plane grating, line source 1 is for sending the light source of rectangle directional light, this light source is installed in the image sensing surface of line array CCD 2 and the center line of reflective mirror to become in the same horizontal plane, and makes parallel rays become a angle with horizontal line.

Wherein line array CCD is TCD1500C (5340 pixel), TCD1702C (7500 pixel), TCD2901D (10550 * 3 pixel) etc.

The assembly relation of plane mirror and plane grating as shown in Figure 3, abutting edge 8 will guarantee the minute surface and grating 4 plane parallel of plane mirror 3 during assembling.

Like this, the directional light that sends of line source incide on the plane mirror with a angle and with a corner reflection on the image planes of line array CCD.Utilize line array CCD directly to measure the corner of grating rather than measure the corner of grating indirectly, utilize binaryzation capture card 6 and computing machine 7 to calculate spectrometer spectrum face spectral wavelength by the grating corner of measuring.The corner of plane mirror both had been the corner of grating planar.When grating rotated the θ angle, the position of parallel rays on line array CCD was x, can measure the corner of grating and obtain spectral wavelength λ on the spectrometer spectrum face by the measurement of x value.

Claims (4)

1. a line array CCD is measured the grating corner and surveyed spectrometer: it is made up of grating reflective mirror, line source, line array CCD, binaryzation data collecting card and computing machine, it is characterized by: plane grating is provided with reflective mirror, light source is arranged on the image sensing surface of line array CCD and the center line of reflective mirror to become in the same horizontal plane, and parallel rays and horizontal line have a certain degree.

2. a kind of line array CCD as claimed in claim 1 is measured the grating corner and is surveyed spectrometer, and it is characterized by described grating reflective mirror is the plane mirror that is installed on the plane grating; The minute surface of plane mirror is parallel with grating planar.

3. a kind of line array CCD as claimed in claim 1 is measured the grating corner and is surveyed spectrometer, and it is characterized by described line array CCD is TCD1500C, TCD1702C or TCD2901D.

4. a kind of line array CCD as claimed in claim 1 is measured the grating corner and is surveyed spectrometer, it is characterized by described line source for sending the light source of rectangle directional light.

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