CN102213585B

CN102213585B - Single-light-source dual-light-path parallel confocal measurement system

Info

Publication number: CN102213585B
Application number: CN2011100901339A
Authority: CN
Inventors: 余晓芬; 余卿
Original assignee: Hefei University of Technology
Current assignee: Hefei University of Technology
Priority date: 2011-04-11
Filing date: 2011-04-11
Publication date: 2012-07-25
Anticipated expiration: 2031-04-11
Also published as: CN102213585A

Abstract

The invention discloses a single-light-source dual-light-path parallel confocal measurement system which is characterized in that a collimated ray emitted by a laser source is split into two paths of collimated rays through a first ray splitter, one path of collimated ray is subjected to beam splitting through a micro-lens array and irradiates on a lens after sequentially passing through a second light splitter and a third light splitter; the other path of collimated ray irradiates on a digital micro-lens device (DMD) after sequentially passing through a first reflector and a second reflector, is reflected by the third light splitter after being subjected to beam splitting of the DMD, and irradiates on the lens through the third light splitter; and output rays of the lens are focused on the surface of an object to be measured on a working platform through an objective lens group, and reflected rays on the surface of the object to be measured are projected in a CCD (Charge Coupled Device) after sequentially passing through a reflection light path consisting of the objective lens group, the lens, the third light splitter and the second light splitter to complete parallel confocal measurement. The invention can realize accurate measurement.

Description

Single light source double light path parallel confocal measuring system

Technical field

The present invention relates to a kind of three-dimensional appearance optical measuring system.

Background technology

When the parallel confocal measuring system adopts Nipkow rotating disk, micro hole array, micro-optical device (like microlens array) etc. that light beam is cut apart; Though the measuring system precision that makes up is higher; If but light source is the very narrow laser of frequency span, then will inevitably occur a plurality of focal planes because of Tabo effect, and do not have property difference between focal plane and the focal plane; Make parallel confocal measuring system self identification not go out positive focal plane, can't measure; When the parallel confocal measuring system adopts DMD DMD that light beam is cut apart; Can in the space, form the diffraction pattern of DMD self, the real image and the virtual image of DMD institute display image; And the final received image of CCD is the real image of the DMD institute display image that comprised in the Zero-order diffractive pattern of DMD; There is not so-called Tabo effect; But make up the influence of many disturbing factors such as irradiating angle of shake that the measuring system form receives DMD surface micro mirror, incident light like this, measuring accuracy is not high.

At present parallel confocal is measured the beam splitter member that adopts except DMD DMD, all can produce Tabo effect as light source because of laser, and Tabo effect mainly is to cause the positive focal plane can't identification for the influence of measuring;

Summary of the invention

The present invention is for avoiding above-mentioned existing in prior technology weak point, a kind of single light source double light path parallel confocal measuring system is provided so that parallel confocal when measuring because of Tabo effect cause can't the positive focal plane of identification problem be able to overcome.

Technical solution problem of the present invention adopts following technical scheme

The characteristics of single light source double light path parallel confocal measuring system of the present invention are:

The collimated light of LASER Light Source emission is divided into the two-way collimated light through first spectroscope, and wherein one road collimated light is after the microlens array beam splitting, successively through second spectroscope and the 3rd spectroscope) be radiated on the lens; Another road collimated light is through being radiated on the DMD DMD through first catoptron and second catoptron successively, by after the said DMD DMD beam splitting to the reflection of the 3rd spectroscope, and be radiated on the lens through the 3rd spectroscope; The output light of said lens focuses on the measured object surface on the worktable through objective lens, and the measured object surface reflection is incident upon among the CCD via the reflected light path that objective lens, lens, the 3rd spectroscope and second spectroscope constitute successively; Said DMD DMD and microlens array do not switch to works simultaneously.

The present invention utilizes a LASER Light Source that DMD DMD and two beam splitter members of microlens array are thrown light on; Two beam splitter members switch use in asynchronous duty; Promptly when using one of them beam splitter member; Shelter from the another one light path, can realize beam splitting respectively laser.

The present invention does not have this performance of Tabo effect when utilizing DMD DMD as beam splitter member; Make up the parallel confocal measuring system of two beam splitter members of a light source; Compared with present technology; Beneficial effect of the present invention is embodied in: the present invention can find the position of positive focal plane when switching to the illumination path that makes up based on DMD DMD that does not have Tabo effect; When switching to the illumination path of microlens array structure, can accurately measure; Simultaneously, owing to used same LASER Light Source and same measurement light path, two kinds of illumination path positive positions of focal plane down overlap, the deviation of the positive position of focal plane of having avoided causing because of the light source difference.

Description of drawings

Fig. 1 is light channel structure figure of the present invention.

Label among the figure: 1 LASER Light Source, 2 first spectroscopes, 3 microlens arrays, 4 second spectroscopes, 5 the 3rd spectroscopes, 6 lens, 7 lens combination, 8 worktable, 9 are CCD, 10 first catoptrons, 11 second catoptrons, 12 DMD DMD.

Embodiment

Referring to Fig. 1, in the present embodiment, the collimated light of LASER Light Source 1 emission is divided into the two-way collimated light through first spectroscope 2, and wherein one road collimated light is radiated on the lens 6 through second spectroscope 4 and the 3rd spectroscope 5 after microlens array 3 beam splitting successively; Another road collimated light is through being radiated on the DMD DMD 12 through first catoptron 10 and second catoptron 11 successively, by after DMD DMD 12 beam splitting to 5 reflections of the 3rd spectroscope, and warp the 3rd spectroscope 5 is radiated on the lens 6; The output light of lens 6 focuses on the measured object surface on the worktable 8 through objective lens 7; The measured object surface reflection is incident upon among the CCD 9 via the reflected light path that objective lens 7, lens 6, the 3rd spectroscope 5 and second spectroscope 4 constitute successively, forms parallel confocal and measures.

Behind the monochromatic light process periodicity device (like microlens array); The repeatedly Tabo effect of imaging will inevitably take place on light path; In measuring based on the parallel confocal of microlens array; Tabo effect produces repeatedly imaging near can making positive focal plane, is that the measuring system identification does not go out positive focal plane, has had a strong impact on measurement.Introduce after the DMD; Through its modulation to LASER Light Source; Can in the space, form the diffraction pattern of DMD self, the real image and the virtual image of DMD institute display image; And the last received image of CCD is the real image of the DMD institute display image that comprised in the Zero-order diffractive pattern of DMD, does not have Tabo effect; And because used same LASER Light Source and same measurement light path, the positive position of focal plane under two kinds of illumination paths overlaps, the deviation of the positive position of focal plane of having avoided causing because light source is different.During actual measurement, at first shelter from the illumination path that microlens array makes up, utilize the illumination path that does not have Tabo effect to find the position of positive focal plane based on the DMD structure; Shelter from the illumination path that makes up based on DMD again, and the illumination path that utilizes microlens array to make up is measured accurately.

Claims

1. single light source double light path parallel confocal measuring system is characterized in that:

The collimated light of LASER Light Source (1) emission is divided into the two-way collimated light through first spectroscope (2), and wherein one road collimated light is radiated on the lens (6) through second spectroscope (4) and the 3rd spectroscope (5) after microlens array (3) beam splitting successively; Another road collimated light is through be radiated on the DMD DMD (12) through first catoptron (10) and second catoptron (11) successively; By after said DMD DMD (12) beam splitting to the 3rd spectroscope (5) reflection, and be radiated on the lens (6) through the 3rd spectroscope (5); The output light of said lens (6) focuses on the measured object surface on the worktable (8) through objective lens (7), and the measured object surface reflection is incident upon among the CCD (9) via the reflected light path that objective lens (7), lens (6), the 3rd spectroscope (5) and second spectroscope (4) constitute successively; Said DMD DMD (12) and microlens array (3) do not switch to works simultaneously; During actual measurement, at first shelter from the illumination path that microlens array makes up, utilize the illumination path that does not have Tabo effect to find the position of positive focal plane based on the DMD structure; Shelter from the illumination path that makes up based on DMD again, and the illumination path that utilizes microlens array to make up is measured accurately.