The best practical way to do this is to use a small LCD display module which incorporates an LED backlight. The LED backlight in most of these displays include both the LEDs and the diffuser. These are very common, and very cheap these days. You can probably find one in a discarded piece of electronic gear.

A final caveat. Earlier generation LCD displays utilized high-voltage fluorescent tubes for backlights. Such LCD displays are not useful for your application, and none of the above information applies to this type of display.

Sharing is caring!Share PinDo you face the problem of uneven illumination when you are viewing your microscope? If so, you may need to align your microscope by the procedure of “Kohler illumination”. Sounds complicated? Don’t worry, read this article and we will show you how to do it step-by-step.This article coversWhat is Kohler illumination?Is my microscope compatible with Kohler illumination?How to set up Kohler Illumination?Procedures and stepsQ&A:Does Kohler illumination require for phase contrast microscopy?ReferencesWhat is Kohler illumination?Optical microscopes generate the magnified images through the interaction of visible lights and the specimens. Illumination of the specimen is the most important variable in achieving high-quality images in microscopy. However, the light source (i.e., a halogen lamp) used for our microscopes is not homogeneous. Without an adjustment, the light intensity in the center will be much stronger than in the peripheral regions. As a result, the edge of the view field will be dim looking like under a shadow.[In this figure] An example of uneven Illumination.Photo source: https://academic.oup.com/labmed/article/28/11/719/2503687To solve this problem, August Köhler of the Carl Zeiss corporation (yes, the company selling high-end cameras and microscopes today) first introduced a method called “Köhler illumination”. Kohler illumination ensures even illumination of the specimens. This reduces image artifacts and provides high sample contrast.If you are interested in its detail of optical principle, see this link.Is my microscope compatible with Kohler illumination?Köhler illumination requires several optical components to function. Most regular compound microscopes with the Abbe condenser and Iris diaphragm should be able to do so.These components lie in order between the light source and the specimen to control the illumination of the specimen:1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

These components lie in order between the light source and the specimen to control the illumination of the specimen:1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

Nonimaging optics

On most of these small LCD displays the LCD and LED connections are separate and thus easy to identify. The LCD section is usually connected via a ribbon cable type connector with a dozen or so signal connections. (In your application you would leave these completely unconnected.) The LEDs are usually connected with a single pair of small gauge discrete wires (often red & black).

7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

科勒照明

This technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

Köhler illumination requires several optical components to function. Most regular compound microscopes with the Abbe condenser and Iris diaphragm should be able to do so.These components lie in order between the light source and the specimen to control the illumination of the specimen:1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

One way to get reasonably uniform light onto the interior of one box face is to put lights at the opposite face. These lights are spread out over the surface so that the light is fairly uniform by the time it reaches the opposite face.

Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

I need to provide uniform intensity or uniform spread of light using this LED in a particular area(Small region). I have read about diffusers such as engineered diffuser, ground glass diffuser, Light shaping diffuser etc. Which is good for my project? Which diffuser can provide highest efficiency?Small region means the dimensions are length x width x height : 5cm x 5cm x 3cm(rectangular box). Sample is placed at the bottom centre of the box and led is placed 2.7cm away from my sample at the height of 1.5cm

If you are interested in its detail of optical principle, see this link.Is my microscope compatible with Kohler illumination?Köhler illumination requires several optical components to function. Most regular compound microscopes with the Abbe condenser and Iris diaphragm should be able to do so.These components lie in order between the light source and the specimen to control the illumination of the specimen:1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

Second way: you may find that if you power up the displays backlight LEDs, and leave the LCD section un-activated, that the LCD display will go into "transmissive" mode which means it remains perfectly transparent. The whole screen will appear to be uniformly white. It is in fact emitting a very uniform white light. This may not be readily apparent unless you darken the room.

There are two possibilities. First way: you can remove the image-producing LCD glass from the metal frame and simply use the LED backlight and diffuser which are usually a mechanically separate assembly located behind the LCD glass.

[In this figure] An example of uneven Illumination.Photo source: https://academic.oup.com/labmed/article/28/11/719/2503687

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Criticalillumination

4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.

b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

To solve this problem, August Köhler of the Carl Zeiss corporation (yes, the company selling high-end cameras and microscopes today) first introduced a method called “Köhler illumination”. Kohler illumination ensures even illumination of the specimens. This reduces image artifacts and provides high sample contrast.If you are interested in its detail of optical principle, see this link.Is my microscope compatible with Kohler illumination?Köhler illumination requires several optical components to function. Most regular compound microscopes with the Abbe condenser and Iris diaphragm should be able to do so.These components lie in order between the light source and the specimen to control the illumination of the specimen:1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

I don't believe that uniform light intensity within that rectangular box is possible with only one LED. If I would have to do it, I would try a box made from special frosted plexiglas lighted by an array of LEDs outside with a distance of about 1 cm from each LED to the next LEDs and a distance of about 1 to 2 cm to the box. Of course each side of the box should be lighted with an array of LEDs.

Optical microscopes generate the magnified images through the interaction of visible lights and the specimens. Illumination of the specimen is the most important variable in achieving high-quality images in microscopy. However, the light source (i.e., a halogen lamp) used for our microscopes is not homogeneous. Without an adjustment, the light intensity in the center will be much stronger than in the peripheral regions. As a result, the edge of the view field will be dim looking like under a shadow.[In this figure] An example of uneven Illumination.Photo source: https://academic.oup.com/labmed/article/28/11/719/2503687To solve this problem, August Köhler of the Carl Zeiss corporation (yes, the company selling high-end cameras and microscopes today) first introduced a method called “Köhler illumination”. Kohler illumination ensures even illumination of the specimens. This reduces image artifacts and provides high sample contrast.If you are interested in its detail of optical principle, see this link.Is my microscope compatible with Kohler illumination?Köhler illumination requires several optical components to function. Most regular compound microscopes with the Abbe condenser and Iris diaphragm should be able to do so.These components lie in order between the light source and the specimen to control the illumination of the specimen:1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

The LEDs are usually electrically connected in a series-string, or a combination of parallel connected series-strings. Since the LEDs in 99.9% of these units are white LEDs, the forward voltage drop of each is around 3.2 volts. Therefore, each series string in the LED backlight will have a forward voltage drop which is a multiple of this voltage. Typically, around 12 to 20 volts will ignite the backlight once you get the polarity correct. Don't worry if you get the polarity backwards, these are pretty resilient to reverse polarity failure. Use a current-limited bench supply to power the string, set the current limit low (50 mA typical ) and slowly raise the voltage until you see light. Don't go above 20 volts. If you don't see any light reverse the polarity of the connections. Hint: if a black wire is utilized, it is likely the cathode connection to the string, which you would connect to the negative side of your power supply. Also, keep the room lighting dim so you can see the LEDs as they begin to ignite dimly.

a. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

However, if that's all you do, the edges will be lit less well than the middle. The trick to get around this is to put mirrors on the remaining four sides. That takes away the edges of the lit area. If you were to look from the box face that is supposed to receive light and look towards the opposite side, you'd see a infinite array of lights. This provides even illumination from a sufficient distance.

2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

Once you identify the correct polarity, and the approximate required forward voltage, do not try to run the LED to full brightness with a direct connection to the power supply. Insert a current limiting resistor of appropriate value and wattage in either feed-wire connection, then experiment with higher voltage levels to determine the maximum achievable brightness of the LEDs.

8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin

Do you face the problem of uneven illumination when you are viewing your microscope? If so, you may need to align your microscope by the procedure of “Kohler illumination”. Sounds complicated? Don’t worry, read this article and we will show you how to do it step-by-step.This article coversWhat is Kohler illumination?Is my microscope compatible with Kohler illumination?How to set up Kohler Illumination?Procedures and stepsQ&A:Does Kohler illumination require for phase contrast microscopy?ReferencesWhat is Kohler illumination?Optical microscopes generate the magnified images through the interaction of visible lights and the specimens. Illumination of the specimen is the most important variable in achieving high-quality images in microscopy. However, the light source (i.e., a halogen lamp) used for our microscopes is not homogeneous. Without an adjustment, the light intensity in the center will be much stronger than in the peripheral regions. As a result, the edge of the view field will be dim looking like under a shadow.[In this figure] An example of uneven Illumination.Photo source: https://academic.oup.com/labmed/article/28/11/719/2503687To solve this problem, August Köhler of the Carl Zeiss corporation (yes, the company selling high-end cameras and microscopes today) first introduced a method called “Köhler illumination”. Kohler illumination ensures even illumination of the specimens. This reduces image artifacts and provides high sample contrast.If you are interested in its detail of optical principle, see this link.Is my microscope compatible with Kohler illumination?Köhler illumination requires several optical components to function. Most regular compound microscopes with the Abbe condenser and Iris diaphragm should be able to do so.These components lie in order between the light source and the specimen to control the illumination of the specimen:1. Collector lens and/or field lens – collect light from the light source and focus it on the plane of the condenser diaphragm.2. Field diaphragm – control the size of light beam from collector lens.3. Condenser diaphragm – control the size of the light beam into the condenser lens.4. Condenser lens – project the light beam, without focusing it, through the s specimen.[In this figure] Schematics of Köhler illumination.Photo source: https://en.wikipedia.org/wiki/K%C3%B6hler_illuminationThis technique is recommended by all manufacturers of modern microscopes because it works very well. Let’s learn how to calibrate “Kohler illumination” to realize your microscope’s full potential.How to set up Kohler Illumination?Notea. You may need to establish Kohler illumination each time you change the objective.b. This procedure is the same for all microscopes. All the components that need adjusting are “below the stage of an upright microscope” or “above the stage of an inverted microscope”.[In this figure] The condenser/diaphragm part below the stage of an upright microscope is where we need to adjust for Kohler illumination. This example is a Primo Star Laboratory microscope from Carl Zeiss.[In this figure] What you will see under the microscope at each step of Kohler illumination.Procedures and steps1. Rotate the turret of the condenser to the brightfield aperture, which should be open and not house a filter or prism.2. Choose a suitable specimen (well-stained brightfield samples, such as very thin animal or plant tissue).3. Focus on your specimen using transmitted light.4. (Image A in the above figure) Close down the field diaphragm, you should see an octagon-shaped aperture appear (or if it is really badly out of focus, the entire image will get darker). Close the aperture until it occupies about 70% of the field of view.5. (Image B) Focus the condenser with the knobs that raise/lower the entire condenser, the octagon shape should be made as sharp as possible.6. (Image C) Move the octagon shape using the two centering screws to the approximately central point of the viewing field.[In this figure] Align the condenser by adjusting two centering screws.Photo source: Zeiss.7. (Image D) Open up the diaphragm to illuminate ~90% of the view. Center the octagon shape by fine tuning the centering screws.8. (Image E) Open the diaphragm until it is just illuminating the entire view or camera area.9. Adjust the condenser aperture so the contrast of the image is good.Enjoy your exploration under the realigned microscope!Q&A:Does Kohler illumination require for phase contrast microscopy?Yes, uniform illumination of the sample is also critical for advanced illumination techniques such as dark-field, phase contrast, and differential interference contrast (DIC) microscopy.References“Köhler Illumination”“Practical Use of the Microscope”Sharing is caring! Share Pin