CN107429992A

CN107429992A - Three-dimensional measuring apparatus and method for three-dimensional measurement

Info

Publication number: CN107429992A
Application number: CN201580078559.9A
Authority: CN
Inventors: 大山刚; 坂井田宪彦; 二村伊久雄
Original assignee: CKD Corp
Current assignee: CKD Corp
Priority date: 2015-05-11
Filing date: 2015-11-19
Publication date: 2017-12-01
Anticipated expiration: 2035-11-19
Also published as: JP6126640B2; JP2016211986A; TW201640076A; CN107429992B; TWI580927B; WO2016181578A1

Abstract

Three-dimensional measuring apparatus and method for three-dimensional measurement are provided, time of measuring can be shortened when carrying out elevation carrection using phase shift method.Base board checking device (1) includes：Irradiated from the surface of oblique direction printed base plate (2) lighting device (4) of predetermined light pattern, the part for having irradiated light pattern on shooting printed base plate (2) camera (5) and implement the various controls in base board checking device (1) and image procossing, the control device (6) of calculation process.The value of gain or the skew of the light pattern that relation of the control device (6) by using gain and the skew of the light pattern according to predetermined shooting condition determination and the measured coordinate according to the determination of the brightness value of the measured coordinate in view data are related to, and the elevation carrection for being measured coordinate is performed by phase shift method based on the two groups of view data shot under the light pattern of two groups of phase place changes.

Description

Three-dimensional measuring apparatus and method for three-dimensional measurement

Technical field

It the present invention relates to the use of three-dimensional measuring apparatus and method for three-dimensional measurement that phase shift method carries out elevation carrection.

Background technology

In general, it is pre- first on printed base plate is configured in the case of electronic unit being installed on printed base plate Cream solder is printed on fixed electrode pattern.Then, the viscosity based on the cream solder fixes electronics temporarily on printed base plate Part.Afterwards, the printed base plate is imported into reflow ovens, by being welded by predetermined reflow process.Recently, led Enter the previous stage of reflow ovens, it is necessary to check the printing state of cream solder, use three-dimensional measurement sometimes when carrying out the inspection Device.

In recent years it has been proposed that the various so-called contactless three-dimensional measuring apparatus using light, such as propose and use The relevant technology of the three-dimensional measuring apparatus of phase shift method.

In the three-dimensional measuring apparatus using the phase shift method, by by sending the light source of predetermined light and the light source will be come from Light be transformed to have the illumination unit that the grating combination of the light pattern of the light intensity distributions of sinusoidal wave shape (striated) is formed, will Light pattern exposes to measured object (being printed base plate in the case of this).Also, observed using the shooting unit directly over being configured at Point on substrate.As shooting unit, CCD camera being made up of lens and capturing element etc. etc. is used.

Under above-mentioned composition, by shooting unit shooting view data on each pixel light intensity (brightness) I by Following formula (T1) provides.

Wherein, f：Gain, e：Skew,The phase angle of sine wave in its pixel.

Here, by the above-mentioned grating of switching control, the phase of light pattern is made for example with four stages Change, introducing have intensity distribution I corresponding with them₀、I₁、I₂、I₃Picture number According to cancelling f (gain) and e (skew) based on following formula (T2), obtain phase angle

Then, using the phase anglePrinciple based on triangulation calculates being measured on printed base plate (cream solder) Height (Z) (referring for example to patent document 1) in coordinate (X, Y).

For example, in the case where the height (Z) at measured coordinate (X, Y) place is " 0 ", the figure of the coordinate (X, Y) is irradiated to The phase angle of case lightFor " 0 ° ", in the case of with predetermined height, phase angleFor " 10 ° ", so the coordinate (X, Y the phase angle) being related toChanged according to its height.

On the other hand, in recent years, it was also proposed that the phase of light pattern is taken with three phase changes and according to three groups of view data Obtain phase angleTechnology (referring for example to patent document 2).

Citation

Patent document

Patent document 1：The flat 5-280945 publications of Japanese Patent Laid-Open

Patent document 2：Japanese Patent Laid-Open 2002-81924 publications.

The content of the invention

Invent problem to be solved

But, it is necessary to make phase with four stages or three phase changes in existing three-dimensional measuring apparatus, shooting have with Four groups or three groups of images of intensity distribution corresponding to them.That is, due to needing to carry out four times or shoot three times for a point, because This shooting needs the time, and time of measuring may be elongated.It is therefore desirable to time of measuring further shortens.

In addition, above mentioned problem is not necessarily limited to the elevation carrection of the cream solder printed on printed base plate etc., in others three Tie up measurement apparatus field in there is also.

The present invention is to complete in view of the foregoing, and its object is to provide when carrying out elevation carrection using phase shift method The three-dimensional measuring apparatus and method for three-dimensional measurement of time of measuring can be shortened.

The means used to solve the problem

Hereinafter, illustrated for each technical scheme subitem suitable for solving the above problems.In addition, as needed to corresponding Technical scheme mark distinctive action effect.

A kind of 1. three-dimensional measuring apparatus of technical scheme, it is characterised in that including：

Illumination unit, the illumination unit have the light source for sending predetermined light and are transformed to the light from the light source The grating of the light pattern of light intensity distributions with striated, the light pattern can be at least irradiated to measured object；

Phase control unit, the phase control unit control the transfer or switching of the grating, can change it is multigroup from The phase of the light pattern of the illumination unit irradiation；

Shooting unit, the shooting unit can shoot the reflection from the measured object for having irradiated the light pattern Light；And

Graphics processing unit, described image processing unit can be performed based on the view data shot by the shooting unit The three-dimensional measurement of the measured object,

Described image processing unit by using the light pattern according to predetermined shooting condition determination gain and partially The institute that the relation of shifting and the measured coordinate determined according to the brightness value of the measured coordinate in described image data are related to The value of gain or the skew of light pattern is stated,

And performed based on the two groups of view data shot under the light pattern of two groups of phase place changes by phase shift method The elevation carrection of the measured coordinate.

According to above-mentioned technical proposal 1, can by using the light pattern according to predetermined shooting condition determination gain A and Offset B relation (such as A=K (proportionality constant) × B) and the brightness value according to the measured coordinate (x, y) in view data The gain A (x, y) of light pattern or skew B (x, y) value that the measured coordinate (x, y) that V (x, y) is determined is related to, and be based on The height that the two groups of view data shot under the light pattern of two groups of phase place changes by phase shift method be measured coordinate is surveyed Amount.

As above, in the technical program, the elevation carrection of measured object can be carried out based on two groups of view data, therefore Compared with the prior art for needing to carry out four times or shoot three times for a point, comprehensive shooting number is few, can shorten bat Take the photograph the time.As a result, it is possible to it is significantly reduced time of measuring.

In addition, the light from light source irradiation is attenuated when passing through grating first, then declined when being reflected by measured object Subtract, each pixel after being attenuated when finally converting (logic-digital conversion) by A/D in shooting unit as view data Brightness value is obtained.

Therefore, by shooting unit shoot view data each pixel brightness value can by by the brightness of light source, From light source irradiation light pass through grating when attenuation rate, light reflected by measured object when reflectivity, in shooting unit by A/D Conversion efficiency when converting (logic-digital conversion) etc. does multiplication to show.

For example, the brightness of light source (uniform light)：L

The transmitance of grating：G=α sin θs+β

α, β are arbitrary constant.

The reflectivity in coordinate (x, y) on measured object is R (x, y),

The conversion efficiency of each pixel of shooting unit (capturing element) be E,

With the coordinate (x, y) on measured object corresponding to pixel on image brightness value be V (x, y),

The gain of the light pattern in coordinate (x, y) on measured object be A (x, y),

, can be with following formula (F1) in the case that the skew of the light pattern in coordinate (x, y) on measured object is B (x, y) Represent.

[number 1]

V (x, y)=L × G × R (x, y) × E

=A (x, y) sin θ+B (x, y) (F1)

Here, gain A (x, y) can be according to based on " the brightness value V (x, y) of the light of sin θ=1 "_MAXWith based on " sin θ =-1 " the brightness value V (x, y) of light_MINDifference represent, therefore

For example, the transmitance (=mean transmissivity) when grating is θ=0：G_θ=0

Transmitance (=maximum transmission) when grating is θ=pi/2：G_θ=pi/2

Transmitance (=minimum transmitance) when grating is θ=- pi/2：G_{θ=- pi/2}

In the case of can be represented with following formula (F2).

[number 2]

A (x, y)={ (L × G_θ=pi/2× R (x, y) × E)-(L × G_{θ=- pi/2}× R (x, y) × E) }/2

={ (L × R (x, y) × E) × (G_θ=pi/2-G_{θ=- pi/2})}/2···(F2)

In addition, skew B (x, y) is " the brightness value V (x, y) of the light of sin θ=0 ", and be to be based on " the light of sin θ=1 " Brightness value V (x, y)_MAXWith the brightness value V (x, y) of the light based on " sin θ=- 1 "_MINAverage value, therefore can be with following formula (F3) represent.

[number 3]

B (x, y)=L × G_θ=0× R (x, y) × E

={ (L × G_θ=pi/2× R (x, y) × E)+(L × G_{θ=- pi/2}× R (x, y) × E) }/2

={ (L × R (x, y) × E) × (G_θ=pi/2+G_{θ=- pi/2})}/2···(F3)

That is, the maximum V (x, y) of brightness value_MAX, minimum value V (x, y)_MIN, average value V (x, y)_AVCan be respectively with following formula (F4), (F5), (F6) are represented, turn into the relation as shown in Fig. 3 curve map.

[number 4]

V (x, y)_MAX=(L × G_θ=pi/2× R (x, y) × E)=B (x, y)+A (x, y) (F4)

V (x, y)_MIN=(L × G_{θ=- pi/2}× R (x, y) × E)=B (x, y)-A (x, y) (F5)

V (x, y)_AV=(L × R (x, y) × E) × (G_θ=pi/2+G_{θ=- pi/2})/2=B (x, y) (F6)

From the figure 3, it may be seen that the maximum V (x, y) of the brightness value in predetermined coordinate (x, y)_MAXWith the minimum value V of brightness value (x, y)_MINAverage value V (x, y)_AVFor skew B (x, y), skew B (x, y) and maximum V (x, y)_MAXDifference and this is inclined Move B (x, y) and minimum value V (x, y)_MINDifference be respectively gain A (x, y).

In addition, brightness value V (x, y) and the light source proportional change of brightness L or reflectivity R (x, y), therefore for example reflecting Rate R turns into the coordinate position of half, and gain A and skew B value also turn into half.

Then, after above formula (F2), (F3) is turned into following formula (F2 '), (F3 '), if both are added into arrangement, export Following formula (F7).

[number 5]

2A (x, y)/(G_θ=pi/2-G_{θ=- pi/2})=(L × R (x, y) × E) (F2 ')

2B (x, y)/(G_θ=pi/2+G_{θ=- pi/2})=(L × R (x, y) × E) (F3 ')

2A (x, y)/(G_θ=pi/2-G_{θ=- pi/2})=2B (x, y)/(G_θ=pi/2+G_{θ=- pi/2})···(F7)

Also, when solving above formula (F7) for A (x, y), turn into following formula (F8), curve map that can be as shown in Figure 4 that Sample represents.

[number 6]

A (x, y)=B (x, y) × (G_θ=pi/2-G_{θ=- pi/2})/(G_θ=pi/2+G_{θ=- pi/2})

=K × B (x, y) (F8)

Wherein, proportionality constant K=(G_θ=pi/2-G_{θ=- pi/2})/(G_θ=pi/2+G_{θ=- pi/2})

That is, one of brightness L of light source or reflectivity R (x, y) is fixed and make another one change in the case of, with Skew B (x, y) is increased or decreased, and gain A (x, y) also proportionally increases or decreases with skew B (x, y).According to the formula (F8), if it is known that one of gain A or skew B, then can obtain another one.Here, the brightness L of proportionality constant K and light source It is unrelated with reflectivity R, determined by the transmitance G of grating.That is, technical scheme 2,3 can state like that described as follows.

For technical scheme 2. in the three-dimensional measuring apparatus described in technical scheme 1, the relation of the gain and skew is described The relation that gain and the skew uniquely determine each other.

If gain A and skew B are the relations uniquely determined each other, such as by creating expression gain A and offseting B's The number table and table data of relation, skew B can be obtained by gain A, or gain A is obtained by offseting B.

For technical scheme 3. in the three-dimensional measuring apparatus described in technical scheme 1, the relation of the gain and skew is described Gain and the proportional proportionate relationship of the skew.

If gain and skew are proportionate relationships, such as can be with A=K × B+C (wherein, C：The dark current of camera is (partially Move)) as relational expression represent, can be obtained by gain A skew B or by offset B obtain gain A.And then under can turning into The such composition of technical scheme 4 stated.

Technical scheme 4. is in the three-dimensional measuring apparatus described in technical scheme 1, in the light pattern of two groups of phase place changes The brightness value of each pixel of the two group view data of relative phase relation when being respectively 0, γ be respectively V₀、V₁Situation Under,

Described image processing unit obtain meet following formula (1), (2), (3) relation phase angle θ, based on the phase angle θ The elevation carrection is carried out,

V₀=Asin θ+B (1)

V₁=Asin (θ+γ)+B (2)

A=KB (3)

Wherein, γ ≠ 0, A：Gain, B：Skew, K：Proportionality constant.

According to above-mentioned technical proposal 4, by the way that above formula (3) is updated into above formula (1), following formula (4) can be exported.

V₀=KBsin θ+B (4)

If solving above formula for skew B, following formula (5) can be exported.

B=V₀/(Ksinθ+1)···(5)

In addition, by the way that above formula (3) is updated into above formula (2), then following formula (6) can be exported.

V₁=KBsin (θ+γ)+B (6)

If above formula (6) is updated into above formula (5), is arranged as shown in following [numbers 7], then can export following formula (7).

[number 7]

V₁=K × { V₀/(K sinθ+1))sin(θ+γ)+{V₀/(K sinθ+1)}

V₁× (K sin θs+1)=K V₀sin(θ+γ)+V₀

=KV₀{sinθcosγ+sinγcosθ}+V₀

-V₁K sinθ+K V₀cosγsinθ+K V_osinγcosθ+V₀-V₁=0

K(V₀cosγ-V₁)sinθ+KV₀sinγcosθ+(V₀-V₁)=0

(V₀cosγ-V₁)sinθ+V₀sinγcosθ+(V₀-V₁)/K=0 (7)

Here, if provided as " V₀cosγ-V₁=a ", " V₀Sin γ=b ", " (V₀-V₁)/K=c ", then above formula (7) energy It is enough to be represented as following formula (8).

Asin θ+bcos θ+c=0 (8)

Here, as shown in following [numbers 8], if solving above formula (8) for phase angle θ, following [number 9] institutes can be exported The following formula (9) shown.

[number 8]

b²-b²sin²θ=c²+2ac sinθ+a²sin²θ

(a²+b²)sin²θ+2ac sinθ+c²=0

[number 9]

Wherein, a=V₀cosγ-V₁

B=V₀sinγ

c(V₀-V₁)/K

Therefore, in above-mentioned technical proposal 4 " obtain meet following formula (1), (2), (3) relation phase angle θ, and be based on The phase angle θ carries out the elevation carrection " it can be said to and " phase angle θ is obtained based on following formula (9), and carried out based on the phase angle θ The elevation carrection ".Certainly, the algorithm for obtaining phase angle θ is not limited to above formula (9), if meeting above formula (1), (2), the pass of (3) System, then it can also use other form.

In addition, if considering above-mentioned dark current C of camera etc., then measurement accuracy can be further improved.

Technical scheme 5. is in the three-dimensional measuring apparatus described in technical scheme 4, γ=180 °.

According to above-mentioned technical proposal 5, it can differ in phase and be shot twice under 180 ° of two groups of light patterns.

In above formula (2), by being set as γ=180 °, following formula (10) can be exported.

V₁=Asin (+180 ° of θ)+B

=-Asin θ+B (10)

Also, following formula (11) can be exported according to above formula (1), (10), can if solving following formula (11) for skew B Enough export following formula (12).

V₀+V₁=2B (11)

B=(V₀+V₁)/2···(12)

Also, by the way that above formula (12) is updated into above formula (3), following formula (13) can be exported.

A=KB

=K (V₀+V₁)/2···(13)

In addition, if arranging above formula (1) for " sin θ ", then it is changed into following formula (1 ').

Sin θ=(V₀-B)/A···(1′)

Also, by the way that above formula (12), (13) are updated into above formula (1 '), then it can export following formula (14).

Sin θ={ V₀-(V₀+V₁)/2}/{K(V₀+V₁)/2}

=(V₀-V₁)/K(V₀+V₁)···(14)

Here, if solving above formula (14) for phase angle θ, following formula (15) can be exported.

θ=sin^-1[(V₀-V₁)/K(V₀+V₁)]···(15)

That is, phase angle θ can be according to known brightness value V₀、V₁Determined with constant K.

As above, according to above-mentioned technical proposal 5, phase angle θ can be obtained based on fairly simple arithmetic expression, when progress quilt When measuring the elevation carrection of thing, processing can be further speeded up.

Technical scheme 6. is in the three-dimensional measuring apparatus described in technical scheme 4, γ=90 °.

According to above-mentioned technical proposal 6, differ in phase and shot twice under 90 ° of two groups of light patterns.

By being set as γ=90 ° in above formula (2), following formula (16) can be exported.

V₁=Asin (+90 ° of θ)+B

=Acos θ+B (16)

If for " cos θ " arrange above formula (16), are changed into following formula (17).

Cos θ=(V₁-B)/A···(17)

In addition, if arranging above formula (1) for " sin θ ", then it is changed into following formula (1 ') as described above.

Sin θ=(V₀-B)/A···(1′)

Then, if above-mentioned formula (1 '), (17) are updated into following formula (18), it is changed into following formula (19), and by entering one Step arranges following formula (19), export following formula (20).

sin²θ+cos²θ=1 (18)

{(V₀-B)/A}²+{(V₁-B)/A}²=1 (19)

(V₀-B)²+(V₁-B)²=A²···(20)

Also, if upper quadrant (20) substitutes into above formula (3), then it is changed into following formula (21), and by further arranging following formula (21) following formula (22), is exported.

(V₀-B)²+(V₁-B)²=K²B²···(21)

(2-K²)B²-2(V₀+V₁)B+V₀ ²V₁ ²=0 (22)

Here, if solving above formula (22) for skew B, following formula (23) can be exported.

[number 10]

Wherein, B ＞ 0

That is, offseting B can be according to known brightness value V₀、V₁Determined with constant K.

In addition, if substituting into above formula (1 '), (17) in following formula (24), then it is changed into following formula (25), and by further whole Manage the formula (25), export following formula (26).

Tan θ=sin θ/cos θ (24)

={ (V₀-B)/A}/{(V₁-B)/A}···(25)

=(V₀-B)/(V₁-B)···(26)

Also, if solving above formula (26) for phase angle θ, then it can export following formula (27).

θ=tan^-1{(V₀-B)/(V₁-B)}··(27)

That is, phase angle θ can be by using above formula (23), according to known brightness value V₀、V₁Determined with constant K.

As above, according to above-mentioned technical proposal 6, can be based on using " tan^-1" arithmetic expression obtain phase angle θ, therefore energy Enough 360 ° of scopes at -180 °~180 ° carry out elevation carrection, can further increase measured zone.

In three-dimensional measuring apparatus of the technical scheme 7. in technical scheme 1 to 6 described in either a program, possess memory cell, The gain and skew for the light pattern that the memory cell storage calculates beforehand through the measurement result calibrated or be additionally carried out Relation.

For example, the light pattern of three groups or four groups phase place changes is irradiated to datum plate, based on being shot under these light patterns To three groups or four groups of view data determine gain A in each pixel and skew B, constant K is determined according to above formula (3).Thus, root According to above-mentioned technical proposal 7, the more preferable elevation carrection of precision can be carried out in each pixel.

In three-dimensional measuring apparatus of the technical scheme 8. in technical scheme 1 to 6 described in either a program, based at described two groups The two groups of view data shot under the light pattern of phase place change obtain the relation of gain and the skew of the light pattern.

For example, obtaining skew B for all pixels of view data using above formula (12) etc., extract and wherein offset B's It is worth the brightness value V of consistent pixel, creates its histogram.Also, the maximum V of brightness value is determined according to the histogram_MAXMost Small value V_MIN。

As described above, the maximum V of brightness value_MAXWith minimum value V_MINAverage value for skew B, maximum V_MAXAnd minimum Value V_MINThe half of difference be gain A.Based on this, constant K can be determined according to above formula (3).Thus, according to above-mentioned technical proposal 8, the man-hour of calibration can be omitted as above-mentioned technical scheme 7, can further shorten time of measuring.

A kind of 9. method for three-dimensional measurement of technical scheme, is performed, the three-dimensional measuring apparatus includes by three-dimensional measuring apparatus：

Phase control unit, the phase control unit control the transfer or switching of the grating, can change it is multigroup from The phase of the light pattern of the illumination unit irradiation；And

Shooting unit, the shooting unit can shoot the reflection from the measured object for having irradiated the light pattern Light；

The method for three-dimensional measurement includes following process：

Relation obtains process, is obtained beforehand through the measurement result calibrated or be additionally carried out true according to predetermined shooting condition The relation of gain and the skew of the fixed light pattern；

Image obtains process, obtains the two groups of view data shot under the light pattern of two groups of phase place changes；With And

Measure process, using the relation that the gain of the light pattern obtained in process and skew are obtained in the relation with And the light pattern being related to according to the measured coordinate of the brightness value of the measured coordinate in described image data determination Gain or the value of skew, and the elevation carrection of the measured coordinate is carried out based on two groups of view data by phase shift method.

According to above-mentioned technical proposal 9, the effect same with above-mentioned technical proposal 1 and technical scheme 7 and effect are served.

Brief description of the drawings

Fig. 1 is the brief pie graph for schematically showing base board checking device.

Fig. 2 is the block diagram for the electric composition for representing base board checking device.

Fig. 3 is the curve map for the brightness or relation of reflectivity and brightness value for representing light source.

Fig. 4 is to represent gain and the curve map of the relation of skew.

Fig. 5 is the distribution table of the distribution for the quantity for representing the brightness value that each data interval is included.

Fig. 6 is the histogram of the distribution for the quantity for representing the brightness value that each data interval is included.

Embodiment

First embodiment

Hereinafter, it is explained with reference to an embodiment.Fig. 1 is to schematically show three possessed in present embodiment Tie up the brief pie graph of the base board checking device 1 of measurement apparatus.As shown in the drawing, base board checking device 1 includes：Mounting table 3, use In placing the printed base plate 2 as measured object, the cream solder as measurement object is printed with printed base plate 2；As The lighting device 4 of illumination unit, predetermined light pattern is irradiated from the surface of oblique direction printed base plate 2；As shooting unit Camera 5, the irradiation for shooting on printed base plate 2 have the part of light pattern；And control device 6, for implementing inspecting substrate Various controls and image procossing, calculation process in device 1.

Motor 15,16 is provided with mounting table 3, by the motor 15,16 by control device 6 (motor control unit 23) Drive control, so that the printed base plate 2 being positioned on mounting table 3 is sliding to arbitrary direction (X-direction and Y direction) It is dynamic.

Lighting device 4 includes the light source 4a for sending predetermined light and is transformed to have just by the light from light source 4a The liquid crystal grating 4b of the light pattern of the light intensity distributions of string wavy (striated), it can be irradiated from oblique direction printed base plate 2 more The light pattern of the striated of group phase place change.

More specifically, in lighting device 4, from the light that light source 4a is sent by fiber guides to a pair of collector lenses, Turn into directional light there.The directional light is directed to projecting lens via liquid crystal grating 4b.Then, from projecting lens to printing Substrate 2 irradiates the light pattern of striated.

Liquid crystal grating 4b, which is included between a pair of transparency carriers, to be formed liquid crystal layer and is configured on a transparency carrier Common electrode；And multiple band electrodes is set up in parallel on another transparency carrier in a manner of the common electrode is opposed, The switch element (thin film transistor (TFT) etc.) being connected respectively with each band electrode by drive circuit pair carries out on-off control, leads to The voltage that control is applied to each band electrode is crossed, forms the bar being made up of light transmittance high " bright portion " and light transmittance low " dark portion " The grating pattern of line shape.Also, light on printed base plate 2 is irradiated to due to the mould caused by diffraction via liquid crystal grating 4b Paste etc. and as with sinuous light intensity distributions light pattern.

Camera 5 is made up of lens and capturing element etc..As capturing element, cmos sensor is employed.Certainly, shooting member Part not limited to this, such as ccd sensor etc. can also be used.It is transformed by the view data that camera 5 is shot inside the camera 5 To be inputted after data signal in the form of data signal to control device 6 (image data memory cell 24).Also, control dress Put 6 and image procossing described later and inspection processing etc. are implemented based on the view data.On that point, the pie graph picture of control device 6 Processing unit.

Then, the electric composition of control device 6 is illustrated.As shown in Fig. 2 control device 6 includes：Control camera 5 Shooting time camera control unit 21, control lighting device 4 lighting control unit 22, control motor 15,16 motor The image data memory cell 24 for the view data (brightness data) that control unit 23, storage are shot by camera 5, storage are described later The phase data storage for the phase data that the calibration data memory cell 25 of calibration data, storage are calculated based on described image data Unit 26, carry out based on the calibration data and phase data the three-dimensional measurement unit 29 of three-dimensional measurement and based on the three-dimensional The measurement result of measuring unit 29 checks the judging unit 30 of the printing state of cream solder 4.By controlling (the liquid of lighting device 4 Brilliant grating 4b) lighting control unit 22 form present embodiment in phase control unit.

In addition, diagram is omitted, but base board checking device 1 includes input block, the tool being made up of keyboard or touch panel There are the display unit of the display pictures such as CRT or liquid crystal, the memory cell for preserving inspection result etc. and to stencil printer Output unit Deng outgoing inspection result etc. etc..

Then, checks sequence of the base board checking device 1 to printed base plate 2 is described in detail.First, carry out being used to grasp light figure The calibration of discrete (phase distribution) of case.

In liquid crystal grating 4b, due to the difference of the characteristic (skew and gain etc.) of each transistor for being connected with each band electrode , being applied to the voltage of above-mentioned each band electrode can not create a difference yet, even therefore identical " bright portion " or " dark portion ", printing opacity Rate (gray scale) can also be directed to each row corresponding with each band electrode and create a difference.As a result, it is irradiated on measured object Light pattern will not also turn into sinuous preferable light intensity distributions, three-dimensional measuring result is possible to that error can be produced.

Therefore, discrete (phase distribution) of light pattern is grasped in advance, carries out so-called calibration etc..

As the order of calibration, differently prepare height and position 0 in addition with printed base plate 2 first and form the benchmark of plane Face.Reference plane turns into same color with the cream solder as measurement object.That is, the reflectivity phase of cream solder and light pattern Deng.

Then, by irradiating light pattern to said reference face and shooting the light pattern by camera 5, obtain including each coordinate Brightness value view data.It is different when in the present embodiment, from actual measurement described later, when calibration is performed, make light pattern Phase respectively changes 90 °, obtains the four groups of view data shot under each light pattern.

Also, control device 6 calculates the phase angle θ of the light pattern in each coordinate according to above-mentioned four groups of view data, by this Phase angle θ is stored in calibration data memory cell 25 as calibration data.

Also, in the present embodiment, determined according to above-mentioned four groups of view data the light pattern in each coordinate gain A and B and both relations are offset, these are stored in calibration data memory cell 25 as calibration data.Therefore, number is calibrated The memory cell in present embodiment is formed according to memory cell 25, the relation that the process is formed in present embodiment obtains process.

Here, the order for calculating gain A and offseting B is described in detail.Brightness value in each coordinate of four groups of view data (V₀、V₁、V₂、V₃) can be represented with gain A and skew B relation by following formula (H1), (H2), (H3), (H4).

[number 11]

V₀=A sin θs+B (H1)

V₁=A sin (+90 ° of θ)+B=A cos θ+B (H2

V₂=A sin (+180 ° of θ)+B=-A sin θs+B (H3)

V₃=A sin (+270 ° of θ)+B=-A cos θ+B (H4)

If also, by the brightness value (V of four groups of view data₀、V₁、V₂、V₃) be added, and as shown in following [numbers 12] Above formula (H1), (H2), (H3), (H4) are arranged, then can export following formula (H5).

[number 12]

V₀+V₁+V₂+V₃=(A sin θs+B)+(A cos θ+B)

+(-A sinθ+B)+(-A cosθ+B)

=4B

B=(V₀+V₁+V₂+V₃)/4···(H5)

In addition, following formula (H6) can be exported according to above formula (H1), (H3).

[number 13]

According to V₀-V₂=2A sin θs

Sin θ=(V₀-V₂)/2A···(H6)

In addition, following formula (H7) can be exported according to above formula (H2), (H4).

[number 14]

According to V₁-V₃2A cosθ

Cos θ=(V₁-V₃)/2A···(H7)

Also, as shown in following [numbers 15], above formula (H6), (H7) are updated to following formula (H8), is arranged, then can led Go out following formula (H9).

[number 15]

1=sin²θ+cos²θ···(H8)

1={ (V₀-V₂)/2A}²+{(V₁-V₃)/2A}²

4A²=(V₀-V₂)²+(V₁-V₃)²

Wherein, A ＞ 0

Also, gain A is calculated based on the following formula (H10) according to derived from above formula (H5), (H9) and offsets B proportionality constant K.

[number 16]

Also, using the gain A of the light pattern in each coordinate calculated as described above, skew B and proportionality constant K as Calibration data and be stored in calibration data memory cell 25.It is of course also possible to as only using proportionality constant K as calibration data and The composition of storage.

Then, the auditing routine carried out for each inspection area is described in detail.The auditing routine is performed by control device 6.

Control device 6 (motor control unit 23) drive control motor 15,16 first moves printed base plate 2, by camera 5 The visual field and printed base plate 2 on predetermined inspection area (measurement range) coincide.In addition, inspection area is regarding camera 5 Wild size splits as a unit and in advance a region among the surface of printed base plate 2.

Then, the liquid crystal grating 4b of the switching control lighting device 4 of control device 6, will be formed in liquid crystal grating 4b light The position of grid is set in predetermined reference position.

When liquid crystal grating 4b switching, which is set, to be completed, control device 6 makes lighting device 4 by lighting control unit 22 Light source 4a lights, and starts to irradiate predetermined light pattern, and by the drive control camera 5 of camera control unit 21, start shooting and shine The inspection area part of the light pattern is penetrated.In addition, the view data shot by camera 5 is transmitted to image data storage apparatus 24 and store.

Similarly, above-mentioned a series of processing is carried out under 180 ° of light pattern making the phase of light pattern for example change. Thus, for predetermined inspection area, the two groups of picture numbers shot under two groups of light patterns for making 180 ° of phase change are obtained According to.The image that the process is formed in present embodiment obtains process.

Also, control device 6 calculates the phase of the light pattern at each coordinate by phase shift method from above-mentioned two groups of view data Angle θ, phase data memory cell 26 is stored in as phase data.Specifically, above-mentioned two are referred to based on above formula (15) The brightness value V of each coordinate in group view data₀、V₁(calibration is based on the calibration data for being stored in calibration data memory cell 25 Each coordinate proportionality constant K), calculate the phase angle θ of the light pattern at each coordinate.

Then, control device 6 (three-dimensional measurement unit 29) compares the calibration data for being stored in calibration data memory cell 25 (phase angle of each coordinate based on calibration) and phase data (each seat based on actual measurement for being stored in phase data memory cell 26 Target phase angle), the offset of the coordinate with same phase angle is calculated, the principle based on triangulation obtains inspection area Altitude information at each coordinate.The process forms the measurement process in present embodiment.

For example, in the case where the measured value (phase angle) for being measured coordinate (x, y) place is " 10 ° ", detection is somebody's turn to do " 10 ° " Value is in by the way which position in the data stored calibrated.Here, if comparing adjacent three pictures with measured coordinate (x, y) There are " 10 ° " in element, then that pixel of fringes shift three for meaning light pattern.Further, it is possible to irradiating angle based on light pattern and The offset of the striped of light pattern obtains the altitude information (z) of measured coordinate (x, y) by the principle of triangulation.

Also, the high number of degrees at each coordinate of control device 6 (three-dimensional measurement unit 29) based on resulting inspection area According to the print range for detecting the cream solder higher than reference plane, the height at each position in the range of this is integrated, thus calculated Go out the amount of printed cream solder.

Also, control device 6 (judging unit 30) is by the position for the cream solder as above obtained, area, height or amount etc. Data judge compared with the reference data prestored, whether judge this in the allowed band according to the comparative result The quality of the printing state of cream solder in inspection area.

During the processing is carried out, the drive control motor 15,16 of control device 6, printed base plate 2 is moved to next Inspection area, afterwards, above-mentioned a series of processing is repeated in whole inspection areas, thus the overall inspection of printed base plate 2 Come to an end beam.

As described in detail above, according to present embodiment, by using the light figure according to predetermined shooting condition determination The gain A of case and skew B relation (such as A=K (proportionality constant) × B) and according in view data measured coordinate (x, Y) gain A (x, y) for the light pattern that the measured coordinate (x, y) that brightness value V (x, y) is determined is related to offsets B's (x, y) Value, measured seat can be carried out by phase shift method based on the two groups of view data shot under the light pattern of two groups of phase place changes Target elevation carrection.

As above, two groups of view data can be based on and carry out elevation carrection, therefore with needing to carry out four times for a point Or the prior art of shooting three times is compared, comprehensive shooting number tails off, and can shorten shooting time.As a result, it is possible to significantly Shorten time of measuring in ground.

Second embodiment

Hereinafter, it is explained with reference to second embodiment.In addition, for first embodiment identical constituting portion Point, same symbol is marked, description is omitted.

In the above-described first embodiment, it is configured to obtain the gain A of the light pattern at each coordinate beforehand through calibration With skew B relation (proportionality constant K), but this is that instead of, in this second embodiment, be configured to based on shooting in actual measurement The two groups of view data shot under the light pattern of two groups of phase place changes obtain the gain A of light pattern and skew B relation (proportionality constant K).

As its order, skew B is obtained for all pixels of view data first by above formula (12).Then, wherein The brightness value V (=Asin θ+B) of the extraction skew B consistent pixel of value, is made its histogram.Fig. 5,6 represent one Example.But Fig. 5,6 exemplified with gain A be " 1 ", skew B be " 0 " situation.Fig. 5 is that brightness value V is divided into " 0.1 " width The data interval of degree and the distribution table for representing the quantity for the brightness value that the data interval is included, Fig. 6 be draw the quantity it is straight Fang Tu.

Then, the maximum V of brightness value is determined based on the histogram_MAXWith minimum value V_MIN.By using the spy of " sin θ " Property, it can determine that caused two peak values are respectively as the maximum V of brightness value in above-mentioned histogram_MAXWith minimum value V_MIN。 In the example shown in Fig. 5,6, brightness value V enters " -1.0~-0.9 " and " the brightness value V's of 0.9~1.0 " data interval Number is respectively " 51 ", is here two peak values.

Then, the maximum V based on brightness value_MAXWith minimum value V_MINCalculate gain A and skew B.As described above, brightness value Maximum V_MAXWith minimum value V_MINAverage value for skew B, maximum V_MAXWith minimum value V_MINThe half of difference be gain A. That is, as shown in fig. 6, the median of two peak values is skew B, the width half of two peak values is gain A.

Proportionality constant K (with reference to above-mentioned formula (3)) can be determined based on the gain A so obtained and skew B value

According to present embodiment, the man-hour of the such calibration of above-mentioned first embodiment can be omitted, can further be contracted Short time of measuring.

In addition, being not limited to the contents of above-mentioned embodiment, for example can also implement as follows.Certainly, non-example below Other application examples, the modification shown are also obvious.

(a) in the above-described embodiment, three-dimensional measuring apparatus is embodied in the paste weldering that measurement printing is formed at printed base plate 2 The base board checking device 1 of the height of material, but not limited to this, such as can also to be embodied in the scolding tin that is printed on substrate of measurement convex The composition of the height of other objects such as block, the electronic unit installed on substrate.

(b) in the above-described embodiment, it is configured to be made up of for the light from light source 4a to be transformed to liquid crystal grating 4b The grating of the light pattern of striated and the switching control grating, thus change the phase of light pattern.But not limited to this, such as It can also be configured to transfer grating components by transfer units such as piezo actuators, change the phase of light pattern.

(c) in the above-described embodiment, it is configured in actual measurement based on being differed in phase under 180 ° of two groups of light patterns Two groups of view data of shooting carry out elevation carrection.Instead of this, such as can also be configured to based on differing two groups of 90 ° in phase The two groups of view data shot under light pattern carry out elevation carrection.In this case, can by using above formula (23), (27) Utilize the brightness value V of each coordinate in two groups of view data₀、V₁The light pattern at each coordinate is calculated with known proportionality constant K Phase angle θ.

Certainly, if in addition, meet above formula (1), (2), the relation of (3), other form can also be used.As To the general expression of phase angle θ, above formula (9) can be included as one (with reference to [number 9]).

(d) in the above-described first embodiment, it is configured to based on differing what is shot under 90 ° of four groups of light patterns in phase Four groups of view data are calibrated, but not limited to this, such as can also be configured to based in three groups of different light patterns of phase Under three groups of view data shooting calibrated.

In addition, when calibration is performed, the brightness that can also change light source is repeatedly calibrated.If turning into the composition, Dark current (skew) C of such camera 5 shown in following formula (28) can then be obtained.

A=KB+C (28)

Wherein, A：Gain, B：Skew, C：The dark current (skew) of camera, K：Proportionality constant.

Or gain A and skew B relation are obtained not as formula, and by creating the pass for representing gain A and offseting B The number table and table data of system, skew B can be obtained according to gain A or gain A is obtained according to skew B.Also, it can also replace Calibration obtains gain A using measurement result being additionally carried out etc. and offsets B relation.

(e) in the above-described 2nd embodiment, it is configured to shoot under 180 ° of two groups of light patterns based on differing in phase Two groups of view data obtain proportionality constant K etc. for all pixels of view data.

Not limited to this, such as can also be configured to based on differing shot under 90 ° of two groups of light patterns two groups in phase View data obtains proportionality constant K etc..Alternatively, it is also possible to be configured to not be all pixels of view data and in measured coordinate A part of scope of the view data such as periphery obtain proportionality constant K etc..

Symbol description

1 ... base board checking device, 2 ... printed base plates, 4 ... lighting devices, 4a ... light sources, 4b ... liquid crystal gratings, 5 ... phases Machine, 6 ... control devices, 24 ... image data memory cells, 25 ... calibration data memory cell, the storage of 26 ... phase datas are single Member, V₀、V₁、V₂、V₃... brightness value, A ... gains, B ... skews, K ... proportionality constants.

Claims

A kind of 1. three-dimensional measuring apparatus, it is characterised in that including：

Illumination unit, the illumination unit with the light source for sending predetermined light and by the light from the light source be transformed to The grating of the light pattern of the light intensity distributions of striated, the light pattern can be at least irradiated to measured object；

Phase control unit, the phase control unit control the transfer or switching of the grating, can changed multigroup from described The phase of the light pattern of illumination unit irradiation；

Shooting unit, the shooting unit can shoot the reflected light from the measured object for having irradiated the light pattern； And

Graphics processing unit, described image processing unit can be based on described in the view data execution shot as the shooting unit The three-dimensional measurement of measured object,

Described image processing unit by using the light pattern according to predetermined shooting condition determination gain and skew The light that relation and the measured coordinate determined according to the brightness value of the measured coordinate in described image data are related to The value of gain or the skew of pattern,

And described in being performed based on the two groups of view data shot under the light pattern of two groups of phase place changes by phase shift method It is measured the elevation carrection of coordinate.
2. three-dimensional measuring apparatus as claimed in claim 1, it is characterised in that

The relation of the gain and skew is the relation that the gain and the skew uniquely determine each other.
3. three-dimensional measuring apparatus as claimed in claim 1, it is characterised in that

The relation of the gain and skew is the gain and the proportional proportionate relationship of the skew.
4. three-dimensional measuring apparatus as claimed in claim 1, it is characterised in that

Two groups of view data when the relative phase relation of the light pattern of two groups of phase place changes is respectively 0, γ The brightness value of each pixel is respectively V₀、V₁In the case of,

Described image processing unit obtain meet following formula (1), (2), (3) relation phase angle θ, and entered based on the phase angle θ The row elevation carrection,

V₀=Asin θ+B ... (1)

V₁=Asin (θ+γ)+B ... (2)

A=KB ... (3)

Wherein, γ ≠ 0, A：Gain, B：Skew, K：Proportionality constant.
5. three-dimensional measuring apparatus as claimed in claim 4, it is characterised in that

γ=180 °.
6. three-dimensional measuring apparatus as claimed in claim 4, it is characterised in that

γ=90 °.
7. the three-dimensional measuring apparatus as any one of claim 1 to 6, it is characterised in that

Possesses memory cell, the light that the memory cell storage calculates beforehand through the measurement result calibrated or be additionally carried out The relation of gain and the skew of pattern.
8. the three-dimensional measuring apparatus as any one of claim 1 to 6, it is characterised in that

The light pattern is obtained based on the two groups of view data shot under the light pattern of two groups of phase place changes Gain and the relation of skew.
9. a kind of method for three-dimensional measurement, is performed by three-dimensional measuring apparatus, the three-dimensional measuring apparatus includes：

Illumination unit, the illumination unit with the light source for sending predetermined light and by the light from the light source be transformed to The grating of the light pattern of the light intensity distributions of striated, the light pattern can be at least irradiated to measured object；

Phase control unit, the phase control unit control the transfer or switching of the grating, can changed multigroup from described The phase of the light pattern of illumination unit irradiation；And

Shooting unit, the shooting unit can shoot the reflected light from the measured object for having irradiated the light pattern；

The method for three-dimensional measurement includes following process：

Relation obtains process, is obtained beforehand through the measurement result calibrated or be additionally carried out according to predetermined shooting condition determination The relation of gain and the skew of the light pattern；

Image obtains process, obtains the two groups of view data shot under the light pattern of two groups of phase place changes；And

Process is measured, utilizes the relation and root of gain and the skew that the light pattern obtained in process is obtained in the relation The gain for the light pattern that the measured coordinate determined according to the brightness value of the measured coordinate in described image data is related to Or the value of skew, and the elevation carrection of the measured coordinate is carried out based on two groups of view data by phase shift method.