CN102012218A - Parallel confocal measurement system based on digital micro-mirror light source and measurement method thereof - Google Patents

Abstract

The invention relates to a parallel confocal measurement system based on a digital micro-mirror light source and a measurement method thereof. The parallel confocal measurement system is characterized in that the system is provided with a digital micro-mirror device (DMD) system which is composed of a DMD micro-mirror control system and a DMD chip and can control the deflection of any micro-mirror in the DMD chip; the light beam given off by an alignment light source is reflected in the DMD system, the reflected light formed by the DMD system passes through an imaging lens to form a light source for measurement; and the light source for measurement passes through a spectroscope system and a telescope system in turn to project on the surface of an object to be measured on a working platform, and the object to be measured reflects the light beam projected on the surface to an array CCD, thus the parallel confocal measurement system can be built. The invention utilizes the DMD to build a flexible digital micro-mirror light source and applies the light source in the parallel confocal measurement system, thus the deflection state of each micro-mirror in the micro-mirror array can be controlled conveniently and fast as required and flexible light sources with different shapes and sizes can be built.

Description

Parallel confocal measuring system and measuring method based on digital micromirror light source

Technical field

The present invention relates to be applied to the measuring system that three-dimensional appearance detects, a kind of parallel confocal measuring system of more specifically saying so.

Background technology

Traditional parallel confocal microscope adopts Nipkow rotating disk, micro hole array, micro-optical device (as microlens array etc.) to realize cutting apart light beam usually, thereby becoming multiple spot by spot measurement measures simultaneously, but in a single day these optical device are made, the parameter of light source is just fixing, just must change optical device if will change the distribution and the size of light source point, this has not only improved cost, has also limited the certain applications of parallel confocal system.

Summary of the invention

The present invention is for avoiding above-mentioned existing in prior technology weak point, a kind of shape, size that can change light source arbitrarily is provided, change parameters such as array of source density, obtain the parallel confocal measuring system based on digital micromirror light source of the ability of surface information to strengthen the parallel confocal measuring system.

Technical solution problem of the present invention adopts following technical scheme

The characteristics that the present invention is based on the parallel confocal measuring system of digital micromirror light source are: the DMD system that constitutes, can control the deflection of arbitrary micro mirror in the dmd chip with DMD micromirror control system and dmd chip is set; The light beam that collimated light source sends forms reflection in described DMD system, the reflected light that is formed by described DMD system forms the required light source of measurement through imaging len, the required light source of described measurement is projected on measured object surface on the worktable through spectroscope and telescopic system successively, to be projected on its surperficial beam reflection to area array CCD by described measured object, constitute the parallel confocal measuring system.

Compared with the prior art, beneficial effect of the present invention is embodied in:

The present invention utilizes DMD to make up a kind of digital micromirror light source of flexibility, and be applied to the parallel confocal measuring system, can control the deflection state of each micro mirror in the micro mirror array quickly and easily as required, thereby construct the flexible light source of difformity, any size.

Description of drawings

Fig. 1 is for being used to eliminate Tabo effect is measured influence to parallel confocal DMD control flow chart among the present invention.

Fig. 2 surface measurements has the DMD control flow chart of the measured object of stria.

Fig. 3 is principle of the invention figure.

Number in the figure: 1 collimated light source, 2 is DMD system, 3 imaging lens, 4 spectroscopes, 5 telescopic systems, 6 worktable, 7 area array CCDs 7.

Embodiment

Referring to Fig. 3, present embodiment is provided with the DMD system 2 that constitutes with DMD micromirror control system and dmd chip, when the DMD in the parallel confocal measuring system carries out work, each micro mirror can be distinguished with the form of coordinate in length and breadth, by the DMD micromirror control system micro mirror on each coordinate points is programmed again, control their deflection situation respectively.

As shown in Figure 3, the light beam that collimated light source 1 sends forms reflection in DMD system 2, the reflected light that is formed by DMD system 2 forms the required light source of measurement through imaging len 3, measure required light source and be projected on measured object surface on the worktable 6 through spectroscope 4 and telescopic system 5 successively, to be projected on its surperficial beam reflection to area array CCD 7 by measured object, constitute the parallel confocal measuring system.

Dmd chip is the optical device that is made of 800 ' 600 micro mirror array, wherein each micro mirror all have 0 ° ,+12 ° and-12 ° of three kinds of states, micro mirror is in " inoperative " state in the time of 0 °; Under the duty, micro mirror will shine and next light reflection back formation light source point in the time of+12 °, then be absorbed the screen absorption through the micro mirror light reflected in the time of-12 °, not participate in making up light source.DMD micromirror control system involved in the present invention can be programmed to the micro mirror on each coordinate points in the micro mirror array, control their deflection situation respectively, so just can control+position of micro mirror in micro mirror array of 12 ° of deflections distributes arbitrarily, thereby forms required light source.

Setting up departments, the wavelength of collimated light source is λ in the system, and the measurement range is L, and the lateral resolution of system requirements is δ, and the magnification of system is M, and dmd chip is the micro mirror array that is made of m ' n micro mirror, and the length of side of each square micro mirror is d ₀, the position d of each micro mirror in array _{I, j}Expression, wherein i and j represent the horizontal ordinate and the ordinate of this micro mirror respectively, i=1,2 ..., m; J=1,2 ..., n; The pointolite size of k ' k micro mirror formation is kd so ₀' kd ₀

Measuring method in the present embodiment is carried out as follows:

A, by the formula z=2d/l of Taibo spacing, reach L for making system's range, then constructed light source cycle d=d ₁, this moment pointolite spacing N ₁=d ₁/ d ₀

B, control d _{I, j}Deflection+12 °, wherein $\begin{array}{c}i=1+a{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>\; </figure-callout>}}_1,2+a{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1,\&CenterDot;\&CenterDot;\&CenterDot;,k+a{N}_1\\ j=1+b{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>\; </figure-callout>}}_1,2+b{\mathrm{<figure-callout\; id="1"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_1,\&CenterDot;\&CenterDot;\&CenterDot;,k+b{N}_1\\ a=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[m/(k+N_1)]\\ b=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[n/(k+N_1)]\end{array}$

The preview light source is constructed in all the other micro mirror deflections-12 °; Determine the positive position of focal plane of pointolite corresponding region by described preview light source;

C, by d ₂=d/M determines light source periodic light source dot spacing N ₂=d ₂/ d ₀

D, control d _{I, j}Deflection+12 °, wherein $\begin{array}{c}i=1+a{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>\; </figure-callout>}}_2,2+a{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_2,\&CenterDot;\&CenterDot;\&CenterDot;,k+a{N}_2\\ j=1+b{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>\; </figure-callout>}}_2,2+b{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_2,\&CenterDot;\&CenterDot;\&CenterDot;,k+b{N}_2\\ a=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[m/(k+N_2)]\\ b=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[n/(k+N_2)]\end{array}$

Measurement light source is constructed in all the other micro mirror deflections-12 °; Under the situation of finding out positive position of focal plane, carry out parallel confocal with measurement light source and measure, obtain the coordinate figure of each sampled point.

The control flow of above-mentioned measuring method as shown in Figure 1, this measuring method can be eliminated the influence that Tabo effect is measured parallel confocal.

When if there is stria on the measured object surface, also can measure the surface topography of groove width and all the other positions, surface by this method, measuring method is:

1, control d _{I, j}Deflection+12 °

i＝1+aN ₂，2+aN ₂，…，N ₁+aN ₂

j＝1，2，…，n

a＝0，1，2，…，[m/(N ₁+N ₂)]

All the other micro mirror deflections-12 °, the structure thickness is d ₁, spacing is d ₂The longitudinal stripe light source;

When 2, the striped light source irradiation is on stria, can two breaks occur, calculate the break width y under the longitudinal stripe at the edge of groove ₁

3, control d _{I, j}Deflection+12 ° $\begin{array}{c}i=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,m\\ j=1+b{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032660720000021.png"\; state="\{\{state\}\}">N</figure-callout>}}_4,2+b{N}_4,\&CenterDot;\&CenterDot;\&CenterDot;,\\ b=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[n/(N_3+N_4)]\end{array},N_3+b{N}_4$

All the other micro mirror deflections-12 °, the structure thickness is d ₃, spacing is d ₄The travers light source;

4, the break width y under the calculating travers ₂

5, work as y ₁, y ₂ ¹0 o'clock, by

Calculate the actual width of stria;

And work as y ₁=0 o'clock, y=y ₂Otherwise, y=y ₁

6, determine light source periodic light source dot spacing N=d/d by d=d/M ₀

7, control d _{I, j}Deflection+12 °, wherein $\begin{array}{c}i=1+aN,2+aN,\&CenterDot;\&CenterDot;\&CenterDot;,k+aN\\ j=1+bN,2+bN,\&CenterDot;\&CenterDot;\&CenterDot;,k+bN\\ a=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[m/(k+N)]\\ b=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[n/(k+N)]\end{array}$

All the other micro mirror deflections-12 ° have made up measurement light source;

8, with measurement light source parallel confocal is carried out in all the other positions, surface and measure, obtain the coordinate figure of each sampled point.Its control flow as shown in Figure 2.

Claims (2)

1. based on the parallel confocal measuring system of digital micromirror light source, it is characterized in that: the DMD system (2) with DMD micromirror control system and dmd chip deflection that constitute, that can control arbitrary micro mirror in the dmd chip is set; The light beam that collimated light source (1) sends forms reflection in described DMD system (2), the reflected light that is formed by described DMD system (2) forms the required light source of measurement through imaging len (3), the required light source of described measurement passes through spectroscope (4) and telescopic system (5) successively and is projected on measured object surface on the worktable (6), to be projected on its surperficial beam reflection to area array CCD (7) by described measured object, constitute the parallel confocal measuring system.

2. the measuring method of the described parallel confocal measuring system based on digital micromirror light source of a claim 1,

Setting up departments, the wavelength of collimated light source is λ in the system, and the measurement range is L, and the lateral resolution of system requirements is δ, and the magnification of system is M, and dmd chip is the micro mirror array that is made of m ' n micro mirror, and the length of side of each square micro mirror is d ₀, the position d of each micro mirror in array _{I, j}Expression, wherein i and i represent the horizontal ordinate and the ordinate of this micro mirror respectively, i=1,2 ..., m; J=1,2 ..., n; The pointolite size of k ' k micro mirror formation is kd so ₀' kd ₀

It is characterized in that described measuring method carries out as follows:

A, by the formula z=2d/l of Taibo spacing, reach L for making system's range, then constructed light source cycle d=d ₁, this moment pointolite spacing N ₁=d ₁/ d ₀

B, control d _{I, j}Deflection+12 °, wherein: $\begin{array}{c}i=1+a{N}_1,2+a{N}_1,\&CenterDot;\&CenterDot;\&CenterDot;,k+a{N}_1\\ j=1+b{N}_1,2+b{N}_1,\&CenterDot;\&CenterDot;\&CenterDot;,k+b{N}_1\\ a=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[m/(k+N_1)]\\ b=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[n/(k+N_1)]\end{array}$

The preview light source is constructed in all the other micro mirror deflections-12 °; Determine the positive position of focal plane of pointolite corresponding region by described preview light source;

C, by d ₂=d/M determines light source periodic light source dot spacing N ₂=d ₂/ d ₀

D, control d _{I, j}Deflection+12 °, wherein $\begin{array}{c}i=1+a{N}_2,2+a{N}_2,\&CenterDot;\&CenterDot;\&CenterDot;,k+a{N}_2\\ j=1+b{N}_2,2+b{N}_2,\&CenterDot;\&CenterDot;\&CenterDot;,k+b{N}_2\\ a=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[m/(k+N_2)]\\ b=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,[n/(k+N_2)]\end{array}$

Measurement light source is constructed in all the other micro mirror deflections-12 °; Under the situation of finding out positive position of focal plane, carry out parallel confocal with measurement light source and measure, obtain the coordinate figure of each sampled point.

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