The digital microscope is characterized by being equipped with a digital camera that allows images of the sample to be captured. These images can be viewed in real-time on a screen built into the microscope or transmitted to a computer.
In the digital microscope, the camera is located in the place of the eyepiece. This means that in general digital microscopes do not allow you to see the sample with your eyes. An exception is trinocular microscopes, these are equipped with two eyepieces to observe the sample with the eyes and a third eyepiece where a digital camera is placed.
Types of digital microscope
There are different types of digital microscopes that can be differentiated based on their complexity.
The simplest digital microscopes simply consist of a conventional monocular or binocular microscope along with a digital camera that can be attached to the eyepiece. This way of digitizing the image of the sample is very common among fans of microscopy because it allows changing the digital camera without also having to change the microscope. In microscopes that have the digital camera built into the equipment, it is not possible to change only the digital camera but the entire microscope must be changed.
Digital microscope with display
For applications related to quality control of materials or in the world of scientific research, it is more common to use digital microscopes with built-in cameras. In this case, the optical system of the microscope is optimized for the digital camera and not for the human eye. This enables slightly higher resolutions and magnifications to be achieved.
Among these types of microscopes, two basic configurations can be distinguished. The simplest have a screen mounted together with the microscope where the digital image of the sample can be viewed. Normally the images captured with this type of microscope can be transmitted to a computer via USB connection or via an SD card.
Advanced digital microscopes are designed to be connected to a computer (i.e., Cyclops). Special software runs from the computer to control the microscope and apply image optimization processes. This type of microscopes is used above all in industry, for applications such as circuit inspection and quality control of materials. This configuration can be found for both conventional microscopes and stereomicroscopes, thus allowing the three-dimensional characteristics of the sample to be captured.
Finally, in recent years the use of the microscope known as the USB microscope has proliferated. This microscope is also a type of digital microscope. Its operation is based on the use of a macro lens attached to a digital camera that connects to the computer via USB. Due to its optical system, the magnification of a USB microscope is considerably lower than that of a conventional digital microscope.
Digital microscope magnification
There is an essential difference between the magnification of a conventional light microscope and the magnification of a digital microscope. In the light microscope, the magnification is calculated by multiplying the magnification provided by the objective and the magnification provided by the eyepiece.
In general, digital microscopes do not have an eyepiece so it is not possible to calculate the total magnification using the above relationship. In this case, the increase is calculated from the size of the sample seen on the screen. That is, the magnification indicates the relationship between the size of the sample on the screen and the size of the actual sample.
One of the key factors that define the quality of digital microscopes is the resolution of the camera used. If the camera is of high resolution, we will be able to increase the image on the screen more without losing quality, so that the total magnification will be greater. If the camera is of low resolution, we will not be able to enlarge the image without it being pixelated, so the total magnification will be less.
In either case, it must be taken into account that the maximum possible magnification of the microscope is around 1500x (Mighty scope). This is due to the nature of light and limits both conventional and digital optical microscopes.
This is important because digital microscopes with magnifications well above 1500x are often advertised. In these cases, the magnification is an empty magnification, that is, it consists of digitally increasing the size of the image but without adding new information.
History of the digital microscope
The appearance of the digital microscope is linked to the popularization of digital cameras. This happened thanks to the invention of the CCD sensor in the late 1960s. The first fully functional digital camera was invented in 1975. A decade later, in 1986, the first digital microscope built by the Japanese company Hirox went on the market. Soon after, the other large microscope manufacturers began offering their first digital models as well.
As the quality of digital cameras has advanced, so has the quality of images obtained using digital microscopes. Technological advances for this type of microscopy have been focused on adding new functionalities to the digital microscope. This includes, for example, improving digital image processing, adding autofocus in microscopes, or allowing three-dimensional digital microscopy.