CN102768976B - A kind of substrate prealignment device and method - Google Patents

Abstract

The invention provides a kind of glass substrate prealignment device and method, can in work stage directly realize to glass substrate with aim at, reduce error, this glass substrate prealignment device comprises: image detection and collecting device, for obtaining the marginal information of substrate; Work stage, for carrying this substrate; Control appliance, produces 6DOF motion for controlling this work stage; This image detection and collecting device comprise three image detectors, and this first image detector is positioned at the first edge of this substrate, and this second, third image detector is positioned at the second edge of this first edge quadrature.

Description

A kind of substrate prealignment device and method

Technical field

The present invention relates to a kind of equipment manufacturing organic light-emitting display device, particularly relate to a kind of substrate prealignment device and method.

Background technology

In current informationized society, display is just play more and more important role in the life of people.In current field of display, the flat-panel monitor (FPD) that the CRT (cathode ray tube) of existing 100 years history is representative by LCD (liquid crystal display) just is gradually substituted, and the New flat panel display that the OLED recently occurred (organic light emitting display) is representative will provide more desirable display frame for people, and tremendous influence is produced to existing display industries general layout.OLED has ultra-thin, active illuminating, high brightness, high-contrast, wide viewing angle, wide operating temperature range, low-power consumption, low cost, the advantage such as all solid state because of it, is considered to the most strong competitor of LCD.And the making of OLED depends on photoetching process, play very important effect at the prealignment of the front glass substrate carrying out photoetching process.

, when glass substrate all can be caused to go up for the first time slice, there is error in the position deviation of glass substrate in upper film magazine, and the carrying error of robot.If upper slice precision does not meet the requirement of mask aligner, then next step technique cannot be carried out.

CN200910209403 provides a kind of mechanical detection method based on touch sensor, and the feature of this device is placement location transducer on plummer, realizes the prealignment to glass substrate; Its shortcoming adopts the alignment methods of contact easily pollute and damage glass substrate, and the program is very strict for the stability requirement of position transducer in addition.

The feature of US6847730 realizes on a robotic arm carrying out prealignment to glass substrate, general scheme is as follows: above a certain fixed position of manipulator, place two CCD, these two CCD are gathered by the marginal information of optical lens to glass substrate, then the marginal information collected by upper step detects position of glass substrate, compare with the ideal position of glass substrate, obtain rotation and the displacement of current glass substrate, thus the position of adjustment manipulator, reach the object of adjustment position of glass substrate; The shortcoming of the program is carried out after prealignment on a robotic arm, and glass substrate is put in work stage by follow-up also need, inevitably introduces error, cause the decline of alignment precision in the process of placement.Another one shortcoming is, the program is attempted by extracting the marginal information of glass substrate with the illumination of CCD side, and the marginal information amount obtained by such lighting system is very limited.

Summary of the invention

For overcoming above-mentioned shortcoming, the invention provides a kind of glass substrate prealignment device and method, can in work stage directly realize to glass substrate with aim at, reduce error.

For achieving the above object, the present invention discloses a kind of substrate prealignment device, comprising: image detection and collecting device, for obtaining the marginal information of substrate; Work stage, for carrying this substrate; Control appliance, produces 6DOF motion for controlling this work stage; This image detection and collecting device comprise at least three image detectors, and this first image detector is positioned at the first edge of this substrate, and this second, third image detector is positioned at the second edge of this first edge quadrature.

Further, this image detection and collecting device also comprise a light source, and the light beam that this light source sends is coaxial with this image detector.This work stage comprises a reflective optical devices, the reflecting surface of this reflective optical devices and this beam orthogonal.This reflective optical devices is a speculum.This image detector is CCD camera.This reflecting surface is greater than the imaging viewing field of this CCD camera.

A kind of substrate pre-alignment method, utilizes a transmission equipment to be positioned over by substrate in a work stage; Obtained the marginal information of substrate by image detection and collecting device, this marginal information comprises the information at the information at the first edge and the second edge with the first edge quadrature; Eccentricity value and the deflection value of this substrate is calculated according to this marginal information; The displacement of this work stage is adjusted according to this eccentricity value and deflection value.

Further, said method specifically comprises: demarcate the work stage coordinate of this marginal information edge calculation point and marginal point described in fitting a straight line; Calculate turning coordinate (x, y) of this substrate according to the work stage coordinate of this marginal point, calculate deflection value (x according to the slope at the second edge _c, y _c); According to length W and the width H of this substrate, and this turning coordinate, this deflection value calculate eccentricity value θ.The marginal point at this first edge is (x _ri, y _ri), n altogether _rindividual; The marginal point at this first edge is (x _bi, y _bi), n altogether _bindividual, fitting a straight line is carried out to this marginal point, to obtain k _r, b _r, k _b, b _b.This Algorithm of fitting a straight line is standard least-squares, and its algorithmic formula is:

$k_R=\frac{n_R\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}{y}_{\mathrm{Ri}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Ri}}}{n_R\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Ri}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\right)}^2}$

$b_R=\frac{\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Ri}}}^2\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Ri}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}{y}_{\mathrm{Ri}}}{n_R\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Ri}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\right)}^2}$

$k_B=\frac{n_B\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}{y}_{\mathrm{Bi}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Bi}}}{n_B\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Bi}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\right)}^2}$

$b_B=\frac{\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Bi}}}^2\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Bi}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}{y}_{\mathrm{Bi}}}{n_B\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Bi}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\right)}^2}.$

When this second edge is parallel with Y-axis, this marginal point is rotated 45 degree around Z axis and carry out fitting a straight line again.

This slope computing formula is: b=(∑ y _i-k ∑ x _i)/n, wherein k is straight slope, bears inverse calculate by long limit slope.。

This turning coordinate computing formula is: $x=\frac{b_B-b_R}{k_R-k_B},y=k_{R}x+b_R.$

This deflection value computing formula is: θ=arctan (-1/k _b).

Eccentricity value computing formula is: x _c=x+Lsin (α+θ), y _c=y-Lcos (α+θ)

Wherein, α=arctan (W/H).

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

The present invention adopts contactless optical alignment mode directly to aim at the glass substrate in work stage, and alignment precision is high, and can not pollute and destroy glass substrate.The invention also discloses a kind of lighting system of novelty, be beneficial to the mechanical layout near photo-etching machine work-piece platform and glass substrate edge information extraction.The present invention gives a set of method utilizing glass substrate edge information to obtain centering directional data simultaneously.

Accompanying drawing explanation

Can be further understood by following detailed Description Of The Invention and institute's accompanying drawings about the advantages and spirit of the present invention.

Fig. 1 is the structural representation of substrate prealignment device involved in the present invention;

Fig. 2 is the schematic diagram of manipulator when transmission glass substrate;

Fig. 3 is the vertical view that glass substrate is positioned in work stage;

Fig. 4 is the contrast schematic diagram of desirable substrate position and the substrate position in fact after sheet;

Fig. 5 calculates the eccentricity value of substrate and the flow chart of deflection value.

Embodiment

Specific embodiments of the invention are described in detail below in conjunction with accompanying drawing.

Main inventive concept of the present invention is to adopt contactless optical alignment mode directly to aim at the glass substrate in work stage, and drives work stage to move to ideal position according to the result after aiming at.

Fig. 1 is substrate involved in the present invention and the structural representation of alignment device.As shown in Figure 1, this substrate prealignment device comprises image detection and collecting device, and this image detection and collecting device are for obtaining the marginal information of substrate.This image detection and collecting device comprise three CCD camera 2A, 2B and 2C (2C is not display on Fig. 1), one of them CCD camera position is for detecting the first edge of this substrate 6, and other two are arranged for the second edge detecting this substrate 6.The present invention schematically illustrates the technical program with three detecting devicess, but those skilled in the art should know and are not limited to three in actual applications.Because substrate 6 is generally rectangle, therefore the first edge and the second edge-perpendicular.Manipulator 1 for transferring to schematic diagram when sextuple travelling workpiece platform 3, Fig. 2 is vertical view and the robotic transfer glass substrate of manipulator from upper film magazine by glass substrate.

When substrate 6 moves to work stage 6 from film magazine by manipulator 1, substrate 6 might not be in ideal position.As shown in Figure 4, Fig. 4 is the contrast schematic diagram of desirable substrate position and the substrate position in fact after sheet.Often between ideal position, there is an eccentric deflection value, the deflection angle θ namely in figure and deflection value (x in the physical location of substrate 6 _c, y _c).

Three CCD camera 2A, 2B and 2C are arranged the top with work stage, and its visual field is for detecting the marginal information on limit 1 and limit 2.CCD camera sends controller 8 to after obtaining the marginal information of the marginal information on limit 1 and limit 2 and carries out hind computation.The marginal information of the glass substrate 6 that controller 8 collects for computed image collecting device 7, and the bias deflection information of glass substrate 6 is calculated with algorithm, the position of the sextuple travelling workpiece platform of further control 3 pairs of glass substrates 6 adjusts, and realizes the prealignment function to glass substrate 6.In Practical Project reality, in order to pursue better technique effect, usually can arrange a brace table 6 below work stage 3, this brace table 6, for supporting work stage 3 and completely cutting off the vibrations from ground, ensures to realize photoetching under stable environment.

CCD camera is when detecting the marginal information of substrate 6, and the order of accuarcy of the information obtained directly determines the order of accuarcy of subsequent technique.In order to realize technique effect better, spy of the present invention arranges additional illumination light source (depending on not going out in figure).The light beam that this lighting source sends is coaxial with this CCD camera, and its object, in order to apply prospect light, is conducive to the extraction of glass substrate edge information.In the realization of this lighting source, the area source of uniform irradiation can be adopted to irradiate three CCD camera simultaneously, also can adopt three independent light sources and to arrange and around CCD camera.

If the prospect light only having light source to bring can meet this technique effect, but the present invention also arranges a reflective optical devices, for glass substrate provides a bias light.After such illumination, the edge of glass substrate 6 more clear the and information of glass baseplate surface also can be very easy to capture by CCD camera 2, be easier to the process for glass substrate edge information in practical application, and calculate eccentric deflection numerical value more accurately.

Fig. 3 is the vertical view that glass substrate is positioned in work stage.As shown in Figure 3, position corresponding with CCD camera in work stage is provided with speculum, is also finally obtained by CCD camera through substrate edges for the beam reflection sent by light source.Wherein, respectively there is a speculum 4A below CCD camera 2A, 2B, 2C, 4B and 4C, and the imaging viewing field of CCD visual field 9A, 9B and 9C corresponding CCD camera 2A, 2B and 2C, the area of speculum 4 is all greater than the imaging viewing field of respective CCD camera 2.

Pre-alignment step and the process of invention are as follows:

Glass substrate in upper film magazine is transferred on sextuple travelling workpiece platform 3 by manipulator 1; The coaxial-illuminating illumination of CCD camera 2 is on glass substrate 6 and speculum 4, and the light reflected through speculum 4 through glass substrate edge, and gets back to CCD camera 2, carries out imaging to the marginal information of glass substrate 6; The image information that 3 CCD camera collect is undertaken gathering by image capture device 7 and sends controller 8 to; Controller 8 processes glass substrate 6 marginal information obtained, and calculates concrete bias deflection value by algorithm; By the bias deflection value obtained, accordingly, controller 8 controls sextuple travelling workpiece platform 3 and carries out accurately translation and rotation process; Glass substrate prealignment terminates.

Fig. 4 is desirable substrate position and the actual comparison diagram by manipulator 1 upper slice metacoxal plate position, 4 will describe how to obtain glass substrate bias deflection numerical value accurately in detail by reference to the accompanying drawings below.

For the ease of subsequent descriptions, the definition coordinate of camera in XY coordinate system is as shown in Figure 4 determined.Definition substrate nominal center is substrate interior distance left side W/2 and intersection point is the point (H is the height of glass substrate, and W is the width of glass substrate) of H/2 to substrate upper left corner distance.Definition nominal center at coordinate origin and the long limit of glass substrate is parallel with y-axis time position be sheet position ideally.

In fact displacement (the x of nominal center in xy plane can be used with the deviation of sheet position ideally in sheet position _c, y _c) and the long limit of glass substrate (H) explain around the rotation θ of z-axis.Displacement (x _c, y _c) being also called eccentricity value, rotation amount θ is also called deflection value or the deviation angle.

In order to measure eccentric deflection value, above sextuple travelling workpiece platform 3, placed 3 CCD camera (2A, 2B, 2C), as shown in Figure 4.The image that CCD camera 2 photographs is carried out to a series of process and draws eccentricity value (x _c, y _c) roughly as follows with the step of deflection value θ:

(1) in controller 8, rim detection is carried out to glass substrate 6 edge image that visual field 9A, 9B, 9C of CCD2A, CCD2B, CCD2C photograph;

(2) according to the work stage coordinate of Calibrate camera calculation of parameter marginal point;

(3) draw marginal position according to step (2), ask the intersection point of two straight lines to draw glass substrate turning coordinate, calculate deflection value according to limit 2 slope;

(4) utilize Given information (glass substrate 6 wide and high) and calculate eccentricity value in conjunction with position of intersecting point and deflection size.

The Mathematical Modeling also relating to an eccentric deflection value in the present invention solves, this Mathematical Modeling be input as the work stage coordinate of two group substrate marginal points and the size W × H of substrate.If the marginal point on limit 1 is: (x _ri, y _ri) be total to n _rindividual, the marginal point on limit 2 is (x _bi, y _bi), n altogether _bindividual, the output of model is (x _c, y _c), θ.

The flow chart calculating this Mathematical Modeling as shown in Figure 5, illustrates how to solve this eccentric deflection value below with reference to Fig. 5.

This Mathematical Modeling is mainly divided into fitting a straight line, find intersection, asks the deviation angle, asks eccentric four parts.Wherein fitting a straight line has again two submodels, two submodel situations that whether corresponding sides 2 are parallel with Y-axis respectively.

The input of fitting a straight line is limit 1 and the work stage coordinate of a series of marginal points on limit 2, and output is the parameter of two linear equations, limit 1:k _r, b _r.Limit 2:k _b, b _b.In general, two classes can be divided into the algorithm that a series of observation station carries out fitting a straight line: standard least-squares (LSF) and Total least squares (TLSF).Standard least-squares calculates straight line parameter according to observation station to the principle that straight line y direction residual error is minimum.And Total least squares carries out calculated line parameter according to observation station to the vertical range residual error minimum principle of straight line.What the present invention adopted is standard least-squares.

If the limit of substrate 2 is just parallel with y-axis, then matching does not go out correct result.In order to avoid this situation occurs, before matching, the some position data of input is rotated 45 degree around z-axis and carry out matching and centering orientation algorithm again.Rotate 45 degree around z-axis again after obtaining a result to reduce.

Standard least-squares:

$k_R=\frac{n_R\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}{y}_{\mathrm{Ri}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Ri}}}{n_R\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Ri}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\right)}^2}$

$b_R=\frac{\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Ri}}}^2\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Ri}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}{y}_{\mathrm{Ri}}}{n_R\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Ri}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Ri}}\right)}^2}$

$k_B=\frac{n_B\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}{y}_{\mathrm{Bi}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Bi}}}{n_B\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Bi}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\right)}^2}$

$b_B=\frac{\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Bi}}}^2\underset{i}{\mathrm{\Σ}}{y}_{\mathrm{Bi}}-\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}{y}_{\mathrm{Bi}}}{n_B\underset{i}{\mathrm{\Σ}}{x_{\mathrm{Bi}}}^2-{\left(\underset{i}{\mathrm{\Σ}}{x}_{\mathrm{Bi}}\right)}^2}.$

Known slopes matching intercept: b=(∑ y _i-k ∑ x _i)/n, wherein k is straight slope, bears inverse calculate by long limit slope.

The model of find intersection is as follows: at the parameter k of known two straight lines _r, b _r, k _b, b _b, when, their intersection point (x, y) can be obtained easily.Ask following equation group:

$\left\{\begin{array}{c}y=k_{R}x+b_R\\ y=k_{B}x+b_B\end{array}\right.$

Draw: $x=\frac{b_B-b_R}{k_R-k_B},$ y＝k _Rx+b _R。

Ask the model of the deviation angle as follows:

The slope on available limit 2 calculates deviation angle θ:

θ＝arctan(-1/k _B)

Ask the model of eccentricity value as follows:

x _c＝x+Lsin(α+θ)

y _c＝y-Lcos(α+θ)

Wherein:

$L+\sqrt{{(W/2)}^2+{(H/2)}^2}$

α＝arctan(W/H)。

Just preferred embodiment of the present invention described in this specification, above embodiment is only in order to illustrate technical scheme of the present invention but not limitation of the present invention.All those skilled in the art, all should be within the scope of the present invention under this invention's idea by the available technical scheme of logical analysis, reasoning, or a limited experiment.

Claims (7)

1. a substrate pre-alignment method, is characterized in that:

Step one, a transmission equipment is utilized to be positioned over by substrate in a work stage;

Step 2, obtain the edge coordinate information of substrate by being arranged on the image detection of described surface and collecting device, described edge coordinate information comprises the coordinate information at the coordinate information at the first edge and the second edge with the first edge quadrature;

Step 3, calculate eccentricity value and the deflection value of described substrate according to described edge coordinate information;

Step 4, adjust the displacement of described work stage according to described eccentricity value and deflection value;

Wherein, described work stage comprises a reflective optical devices, the reflecting surface of described reflective optical devices is vertical with the illuminating bundle that described image detection and collecting device send;

Described illuminating bundle shines on described substrate and optical element, and the light reflected through described optical element through described substrate edges, and gets back to described image detector;

Wherein, described step 3 specifically comprises:

(a), demarcate described edge coordinate information edge calculation point work stage coordinate and fitting a straight line described in marginal point;

(b), calculate turning coordinate (x, y) of described substrate according to the work stage coordinate of described marginal point, calculate deflection value (x according to the slope at the second edge _c, y _c);

(c), according to the length W of described substrate and width H, and described turning coordinate, described deflection value calculate eccentricity value θ.

2. substrate pre-alignment method as claimed in claim 1, it is characterized in that, described step (a) comprising: the marginal point at described first edge is (x _ri, y _ri), n altogether _rindividual; The marginal point at described second edge is (x _bi, y _bi), n altogether _bindividual, fitting a straight line is carried out to described marginal point, to obtain k _r, b _r, k _b, b _b.

3. substrate pre-alignment method as claimed in claim 2, it is characterized in that, described Algorithm of fitting a straight line is standard least-squares, and its algorithmic formula is:

$k_R=\frac{n_R\underset{i}{\Σ}{x}_{Ri}{y}_{Ri}-\underset{i}{\Σ}{x}_{Ri}\underset{i}{\Σ}{y}_{Ri}}{n_R\underset{i}{\Σ}{x_{Ri}}^2-{\left(\underset{i}{\Σ}{x}_{Ri}\right)}^2}$

$b_R=\frac{\underset{i}{\Σ}{x_{Ri}}^2\underset{i}{\Σ}{y}_{Ri}-\underset{i}{\Σ}{x}_{Ri}\underset{i}{\Σ}{x}_{Ri}{y}_{Ri}}{n_R\underset{i}{\Σ}{x_{Ri}}^2-{\left(\underset{i}{\Σ}{x}_{Ri}\right)}^2}$

$k_B=\frac{n_B\underset{i}{\Σ}{x}_{Bi}{y}_{Bi}-\underset{i}{\Σ}{x}_{Bi}\underset{i}{\Σ}{y}_{Bi}}{n_B\underset{i}{\Σ}{x_{Bi}}^2-{\left(\underset{i}{\Σ}{x}_{Bi}\right)}^2}$

$b_B=\frac{\underset{i}{\Σ}{x_{Bi}}^2\underset{i}{\Σ}{y}_{Bi}-\underset{i}{\Σ}{x}_{Bi}\underset{i}{\Σ}{x}_{Bi}{y}_{Bi}}{n_B\underset{i}{\Σ}{x_{Bi}}^2-{\left(\underset{i}{\Σ}{x}_{Bi}\right)}^2}.$

4. substrate pre-alignment method as claimed in claim 2, is characterized in that, when described second edge is parallel with Y-axis, described marginal point is rotated 45 degree around Z axis and carry out fitting a straight line again.

5. substrate pre-alignment method as claimed in claim 2, it is characterized in that, described turning coordinate computing formula is:

$x=\frac{b_B-b_R}{k_R-k_B},y=k_{R}x+b_R.$

6. substrate pre-alignment method as claimed in claim 2, it is characterized in that, described deflection value computing formula is:

θ＝arctan(-1/k _B)。

7. substrate pre-alignment method as claimed in claim 2, it is characterized in that, described eccentricity value computing formula is:

x _c＝x+Lsin(α+θ)

y _c＝y-Lcos(α+θ)

Wherein, α=arctan (W/H).