Lighting Methods with Bar Lights
Bar lights are most commonly used in one of these lighting methods. However, there are additional techniques that are specified in the respective product section.
Brightfield
Through the use of bar lights as a frontlight, the direct illumination causes reflections on the surface (of the inspected part).
Low Angle
By using the bar light in a low angle of incidence you can create contrast on edges and slightly illuminate the surface.
Darkfield
Positioned as a flat-aligned illumination, the bar light strongly highlights edges with almost no light on the surface.
LBA Bar Light with Angle Changers for Machine Vision
wenglor LBA bar lights can be configured to suit almost any application. Pair the LBA bar lights with the optional ZBAG angle changers to widen the beam angle and have flexibility and control of illumination across the field of view. The direct illuminators have a perfect balance between brightness and homogeneity, allowing the product to be used at both small and large working distances. The LBA bar lights can be operated with high intensity in continuous mode or synchronized to the digital camera in strobe mode with increased luminosity (overdrive). They are available with white, red and infrared light.
Machine Vision Bar Lights – Effects and Features
What Is an Angle Changer?
Angle changers are a special type of diffuser that can be attached directly onto the LBA bar light. By increasing the beam angle, angle changers also diffuse the light and help to achieve a better homogeneity across the field of view.
Angle changers are a special type of diffuser that can be attached directly onto the LBA bar light. By increasing the beam angle, angle changers also diffuse the light and help to achieve a better homogeneity across the field of view.
Rapid feasibility testing for new projects: Quickly and easily identify the best illumination solution with our angle changer
Protected IP65 design integrity: No need to dismantle the product to change the beam angle
Huge flexibility: Attach angle changers to suit many working distances and machine vision applications
Impact on Beam Angle
Impact on Brightness
| 43,500 lux | 34,500 lux | 17,400 lux | 43,000 lux | ||||
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| Measurements made at working distance WD = 500 mm with LBAW201, measured in the middle of the field of view (FoV) – strobe overdrive mode. | |||||||
Impact on Brightness
Impact on Exposure Time
| ×2 | ×2.5 | ×5 | ×2 | |||
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| 200 μs | 250 μs | 500 μs | 200 μs | |||
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×2
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×2.5
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×5
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×2
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200 μs
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250 μs
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500 μs
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200 μs
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Creating Excellent Uniformity and Homogeneity in Light
The Curve Effect is a powerful tool for creating excellent uniformity and homogeneity over a large field of view (FoV) such as those in Pick and Place applications. The patented curve effect is created using a bar light LBA with variable intensity along its length and specifically dimming the light in the center of the projected illumination with the use of angle changers.
Bar Lights LBAx1xx
Bar Lights LBAx2xx
Bar Lights LBAx3xx
Bar Lights LBAx5xx
Estimating the illuminated field of view (FoV) covered from a distance according to the chosen LBA bar light + angle changer configurations
- WD is the working distance – i.e. the distance between the LBA and the field of view
- H is the FoV size in a direction perpendicular to the bar length
- L is the FoV size in a direction parallel to the bar length
- U is the useful length of the bar (125 mm/250 mm/375 mm/500 mm)
| LBA | LBA + ZBAG001 | LBA + ZBAG002 | LBA + ZBAG003 | |||||
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| H = | WD × 24/100 | WD × 35/100 | WD × 60/100 | WD × 90/100 | ||||
| L = | (WD × 24/100) + U | (WD × 35/100) + U | (WD × 60/100) + U | (WD × 90/100) + U | ||||
Without angle changers, the bar light’s beam angle is ±7°. This turns it into a spot light at bigger working distances.
A dome effect can also be created using LBA bar lights inside a box. Fitted with medium angle changers (ZBAG002), the bar light illuminates the ceiling of the box which should be made of a white, matte surface. This will create a homogeneous field of view which is perfect for illuminating complex surfaces.
The LBA barlight can be used for line scan applications when fitted with the line angle changer (ZBAG004). The line angle changer creates an elliptical beam angle from each LED. This means that the combined array of all LEDs results in a homogeneous and highly intense line at a minimum working distance of 100 mm.
All angle changer options are available in polarized versions. By combining the angle changers with polarizers, you can also create excellent homogeneity on specular or shiny surfaces.
LBD Diffuse Bar Light without Angle Changers
wenglor LBD bar lights are highly diffuse illuminators, perfect for diffuse low angle illumination, direct illumination at a close working distance and backlighting of specific features on the field of view. Thanks to integrated current control and flexible mounting options, the lighting is very easy to install and perfect for a myriad of Machine Vision and identification applications. They are available with white, red and infrared light.
The illumination surface is so diffused it can be used as a back light to create homogeneous transmitted light. This can be applied where the silhouette of an object needs to be inspected. The following sample pictures were captured using one LBDW101 with a working distance of 220 mm.
The stated working distance in this example is the distance from the camera to the sample part.
The stated working distance in this example is the distance from the camera to the sample part.
See samples on the right →
Screw Head
Milk Cap
Circuit Board
Back Light with Aperture f/4
Back Light with Aperture f/4
Back Light with Aperture f/4
Back Light with Aperture f/4
Back Light with Aperture f/8
Back Light with Aperture f/8
Back Light with Aperture f/8
Back Light with Aperture f/8
The shown samples were captured in each illumination method being common for bar lights. The following sample pictures were captured using two LBDW101 with a working distance of 220 mm and an exposure time of 1 ms.
The stated working distance in this example is the distance from the camera to the sample part.
The stated working distance in this example is the distance from the camera to the sample part.
Screw Head
Milk Cap
Circuit Board
Brightfield with Aperture f/2.8
Brightfield with Aperture f/2.8
Brightfield with Aperture f/2.8
Brightfield with Aperture f/2.8
Low Angle with Aperture f/4
Low Angle with Aperture f/4
Low Angle with Aperture f/4
Low Angle with Aperture f/4
Darkfield with Aperture f/4
Darkfield with Aperture f/4
Darkfield with Aperture f/4
Darkfield with Aperture f/4
LB9 IP69K Machine Vision Bar Light without Angle Changers
Waterproof IP69K Washdown Bar Lights
wenglor LB9 bar lights are industrial IP69K illuminators. The food grade enclosure is perfectly suited for environments subject to high pressure, high temperature washdowns containing steam and cleaning chemicals. The barlights are provided with L-brackets that allow 360° mounting, making them easy to install. They are available with red, infrared and white light.
- Easy installation
- Perfect for food, beverage and pharmaceutical Machine Vision applications
- Designed to withstand the harsh chemical cleaning and decontamination
- Wide ambient operating temperature range
IP69K Cable Gland
- IP69K protection
- For harsh environments
Internal Fans
- For homogenizing temperatures
- For moisture reduction
Ventilation
- For pressure equalization
- For moisture reduction
Smooth Body
- For reducing bacteria
- For easy cleaning
Function Principles and Illumination Techniques
| Brightfield | Low Angle | Darkfield | Dome | Back Light | Angle Changer Compatible | |
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| All bar lights are available with red, infrared and white light. | ||||||
Function Principles and Illumination Techniques
| LBA Bar Light | ||||||
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Brightfield
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Low Angle
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Darkfield
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Dome
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Back Light
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Angle Changer Compatible
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| LBD Bar Light | ||||||
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Brightfield
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Low Angle
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Darkfield
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Dome
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Back Light
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Angle Changer Compatible
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| LB9 Bar Light | ||||||
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Brightfield
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Low Angle
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Darkfield
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Dome
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Back Light
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Angle Changer Compatible
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All bar lights are available with red, infrared and white light.
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