3D AOI TRAINING

(OPERATION LEVEL 1)

March 2013

r02
CONFIDENTIALITY
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privileged. If you are not the intended recipient, don’t proceed further
and delete this file and destroy any copies. Any dissemination or use
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unauthorized and may be illegal.

CONFIDENTIAL
REVISION INFORMATION

Revision Description Date By

01 Initial release Mar 5, 2013 Hanjin Cho
02 Format Change Mar 12, 2013 JD Shin
03 Simpler Explanation Mar 20, 2013 JD Shin
04 Editorial May 16, 2013 David Suh

CONFIDENTIAL
Pre-Setting
PRE SETTING
The purpose of pre-setting is :
To set up the general rule for the following items.

• Extraction
- Body location method
- Lead Tip location method

• 3D measurement algorithm
- Base plane
- Slope compensation
- Noise removal
- ETC

CONFIDENTIAL
Extraction
- Body location method
- Lead Tip location method
Body Location Method
(Body location mode)
BODY EXTRACTION

Correct body extraction is the starting point to detect the body related
defects.

Where is the body?

CONFIDENTIAL
BODY FINDING

There are 7 different settings depending on the components type.

1. Full 3D (Adaptive Height Threshold)

2. Full 3D (Fixed Height Threshold)
3. Corner 3D (Fixed Height Threshold)
4. Full Shadow - 2D
5. White Circle - 2D
6. Black Circle - 2D
7. Two Terminal Chip

CONFIDENTIAL
FULL 3D (ADAPTIVE HEIGHT THRESHOLD.)

This mode automatically takes body area from the top surface portion
in the 3D measurement information.

Body

CONFIDENTIAL
FULL 3D (FIXED HEIGHT THRESHOLD.)

This mode takes the body area at the user-defined height.

Body

CONFIDENTIAL
WHY FIXED HEIGHT THRESHOLD IS NEEDED?

When the component has multiple heights, we have to decide which

one is considered as the main body. Hint: Use the area that leads are
attached to.

Body?

Body?

Applicable types of components

CONFIDENTIAL
CORNER 3D (FIXED HEIGHT THRESHOLD.)

In the case of big size components, this mode is sometimes used for
faster inspection processing speed.

CONFIDENTIAL
FULL SHADOW

When the component height is higher than 5mm, we can check the
body location using the shadow.

3D Light
T
Shadow

L Comp. R
Comp.

[Side View] [Top View]

CONFIDENTIAL
WHITE CIRCLE

For the high height aluminum capacitor(higher than 5mm), the body
cannot be extracted using 3D information.

Using 2D light, the white circle can be seen as the edge of the
component. This is regarded as the body.
The user needs to select the necessary 2D light to acquire the best
image.

CONFIDENTIAL
BLACK CIRCLE

When the color of the circle edge is black, it can be used.

(Currently not used)

CONFIDENTIAL
LEAD REGION RECONSTRUCTION

When 2D body extraction is used, still the user might want to measure
the lead in 3D. In this case, Lead Region Reconstruction should be
turned on.

[Turn off] [Turn on]

CONFIDENTIAL
TWO TERMINAL CHIP

To reduce the ambiguity of body finding for chip components, the 2D

and 3D combination can be used.

Body edge is obvious

[Normal case] [Excessive case]

In this case, 2D information is also used to separate the terminal from

the solder joint.

Distinguishable

CONFIDENTIAL
Extra body location
- Lead shoulder for IC

- Resize body for odd-shape

Body inspection on/off

EXTRA BODY LOCATION

Lead shoulder for IC

- Component body such as SOIC can be extracted as follows when using
only 3D information.

In this case, 2D information is also used to exclude the lead portion.

(Currently not used)

CONFIDENTIAL
EXTRA BODY LOCATION

Resize body for odd-shape

- When body is extracted as the following dotted white box,
it can bring up some confusion for the lead finding.
The size can be reduced or expanded depending on the setting.

X2

Y1 Originally Y2

extracted body

X1

CONFIDENTIAL
EXTRA BODY LOCATION

Resize body for odd-shape

- The following is the adjusted body shape after putting -300um for Y2.

Originally extracted body

Newly extracted body

CONFIDENTIAL
BODY INSPECTION ON/OFF

When the body cannot be extracted, the user can turn off the body
inspection completely.

CONFIDENTIAL
Lead Tip Location Method
(Tip location mode)
LEAD TIP FINDING

There are 3 different settings to find a lead tip.

1. Auto
2. Semi Auto
3. CAD Define

CONFIDENTIAL
LEAD TIP FINDING

• Auto
Automatically find the highest point.

• Semi Auto
Automatically find the highest point in a certain range inside and outside
of the CAD DEFINED location.

• Cad Define
Pre-defined lead length position becomes the lead tip.
【Auto】 【Semi-Auto】 【Cad Define】

Lead Tip Lead Tip Lead Tip

Lead Length(Cad-Defined)
■ Searching direction Lead Length(Pre-defined)

From Pad edge to the body

Lead Tip Search Margin(Body)
Lead Tip Search Margin(Pad End)

CONFIDENTIAL
3D Measurement Algorithm
- Reference Plane Setting
- Slope Compensation
- Noise Removal
- ETC
Reference Plane Setting
REFERENCE PLANE

In order to get the reference plane, the user can set the ROI (Region of
Interest).
Extended ROI

Top(um)

Left(um) Right(um)

Bottom(um)

• By Keyboard : Put the ROI value.

• By Mouse : User can draw the ROI on screen with the Mouse.
• Auto : The size of ROI is automatically set based on the component size.

CONFIDENTIAL
Slope Compensation
SLOPE COMPENSATION

When a board is suffering from warpage, the slope should be

compensated sometimes.

Before compensation After compensation

CONFIDENTIAL
SLOPE COMPENSATION

There are two types of algorithm

• Split ROI Compensation (Currently not used)

• Iterative Plane Fitting

- Base Type : Normal
- Base Type : Transparent

CONFIDENTIAL
SPLIT ROI COMPENSATION

The ROI is divided into many sections. Each section is compensated

locally.

① ①
② ②
③
Comp. ③
④ ④

Currently it’s not used.

CONFIDENTIAL
ITERATIVE PLANE FITTING (BASE TYPE : NORMAL)

ROI is divided into 4 sections. It starts to create the plane iteratively.

① ②

Comp.

③ ④

Before Plane Fitting After Plane Fitting

CONFIDENTIAL
ITERATIVE PLANE FITTING (BASE TYPE : TRANSPARENT)

When the FPCB is highly transparent, it’s difficult to decide the

reference plane. (for LED application)

Non-transparent

Transparency area

Component

Because of the transparency of the board, we can see though the

board. In this case, we can just use the non-transparent portion of the
board for the reference plane.

CONFIDENTIAL
Noise Removal
NOISE REMOVAL

There are 4 major parameters to remove the undesired noise signals.

1. Brightness
2. Darkness
3. Visibility
4. Amplitude

CONFIDENTIAL
BRIGHT THRESHOLD

The 3D AOI camera measures the reflected intensity of the

projected light.

If the average brightness is higher than the setting, we regard

this information as noise.

Filter out
The darkest The brightest

0 255

CONFIDENTIAL
DARK THRESHOLD

The 3D AOI camera measures the reflected intensity of the

projected light.

If the average brightness is lower than the setting, we regard

this information as noise.

Filter out

The darkest The brightest

0 255

CONFIDENTIAL
AMPLITUDE THRESHOLD

When we take 4 pictures, the intensity must change along to the

sinusoidal characteristic. If the intensity change is not big enough, we
regard the information as noise.
Gray value

Amplitude

Worse Amplitude

Phase
Better Amplitude
CONFIDENTIAL
VISIBILITY THRESHOLD

When we take 4 pictures, the intensity must change along to the

sinusoidal characteristic. If the changes are not in right order, we
regard the information as noise.
Modulation
Visibility =
Average
Gray value

Modulation

Worse Visibility

Average

Phase
Better Visibility
CONFIDENTIAL
ETC
3D PROJECTION ON/OFF SWITCHES

Only when the low height component is not measured properly due to
the neighboring high height component (shadowing), the user can
manually turn off each LED projector as necessary for best results.
This is also selectively used to prevent interference between solder
fillets closely adjacent to each other.

CONFIDENTIAL
Measurement Principle
MOIRÉ INTERFEROMETRY (CONCEPT)

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Period

Period

CONFIDENTIAL
PHASE SHIFTED MOIRÉ INTERFEROMETRY

I1 = 256

I2 = 128

I4 = 128

I3 = 1

π π 3π 2π
2 2
I2, I4
256

(I 3, I 4 ) = (1,128) ( I1 , I 2 ) = (256,128)

θ reference

256 I1 , I 3
CONFIDENTIAL
PHASE SHIFTED MOIRÉ INTERFEROMETRY

I2 = 250

I1 = 135

I3 = 120

I4 = 5
π π 3π 2π
2 2
I2, I4
( I1 , I 2 ) = (135, 250)
256

θ object

θ Difference = θ object −θ reference (I 3, I 4 ) = (120, 5)

256 I1 , I 3
CONFIDENTIAL
PHASE SHIFTED MOIRÉ INTERFEROMETRY

I2 = 250
I1 = 256

I1 = 135
I2 = 128

I4 = 128 I3 = 120

I3 = 1
I4 = 5
π π 3π π π 3π
2π 2π
2 2 2 2

θ Difference = θ object −θ reference

π π 3π 2π
CONFIDENTIAL 2 2
PHASE SHIFTED MOIRÉ INTERFEROMETRY

I2 = 250
I2 = 200

I1 = 135
I3 = 125
I3 = 120 I1 = 130

I4 = 10
I4 = 5
π π 3π π π 3π
2π 2π
2 2 2 2

Still the same phase I2, I4

( I1 , I 2 ) = (135, 250)
256

θ object

(I 3, I 4 ) = (120, 5)
CONFIDENTIAL
256 I1 , I 3