Precision optics for imaging and illumination are essential in high-performance endoscopes, enabling interventional and surgical procedures. The endoscope and optics must be at the smallest possible size to reduce pain and discomfort while still being able to access specific body parts. In addition, the electronics on the distal tip must be even smaller to fit within the overall scope. These specifications require know-how and precision optics design, fabrication, and testing experience.

Gray Optics is a leader in developing precision optical systems for biomedical and industrial applications. We strive to provide our customers with technical knowledge and world-class capabilities to help them commercialize their technological innovations. From prototypes to finished products, our production team is motivated to convert our customers’ designs into precision optical assemblies.

What Is an Endoscope?

Product EngineeringAn endoscope is a term that refers to a specific type of medical device and a broad term that encompasses many different types of medical scopes. It is used for endoscopy, the procedure by which a gastroenterologist or a digestive disease specialist diagnoses conditions affecting the esophagus, stomach, and the first part of the small intestine called the duodenum. On the other hand, upper endoscopy is medically known as an esophagogastroduodenoscopy. It uses a tiny camera on the end of a long, flexible tube to visually examine the patient’s upper digestive system.

Endoscopies are sometimes combined with other procedures like ultrasounds. This process is done by connecting an endoscope to an ultrasound device to produce images of the esophageal or stomach wall. Endoscopic ultrasound can also capture images of hard-to-reach organs, such as the pancreas.

What Are the Types of Endoscopes Used in Endoscopy?

Micro OpticsEndoscopes are primarily used to view the body’s internal organs by inserting a tube through an incision or natural opening. These devices can be classified into two types: rigid and flexible. The primary differences between these two endoscopes are how images are captured and which body part is being examined.

Rigid Endoscope

In most surgical endoscopic applications, rigid endoscopes visualize the surface of organs, their vessels, or pathological changes without making large incisions in the body. This type of endoscope is commonly used in minimally invasive surgical procedures such as rhinoscopy (nose), laparoscopy (abdomen), and cystoscopy (urinary bladder).

The structural criteria for rigid endoscopes include the viewing angle, depth-of-field, image brightness and quality, magnification, distortion, and image size. They are made of metal tubes with lenses and light channels, available in various external diameters ranging from 1 to 12 mm.

Moreover, rigid endoscopes are commonly equipped with high-resolution optical glass rod lenses or chip-on-tip cameras. They can be forward-viewing (0°) or angled (10°-120°) to allow visualization away from the telescope’s axis and to increase the field of view (FOV) by rotating the instrument. The optical quality of rigid endoscope images continues to outperform fiber-optic or digital images captured by flexible scopes.

Flexible Endoscope

Fiberscopes are the general term for flexible endoscopes. In contrast to rigid endoscopes that use a relay of lenses to convey images, flexible endoscopes illuminate and capture images using a cluster of precisely aligned flexible optical fibers or miniature CMOS image sensors for chip-on-tip configurations.

Some flexible endoscopes include upper gastrointestinal endoscopes (esophagus, stomach, and duodenum), colonoscopes (colon), and bronchoscopes (bronchial tubes).

In addition, fiber optics and miniature CMOS image sensors enables the development of much more maneuverable instruments. These devices allow surgeons to reach previously inaccessible areas and explore different body parts without causing the patient undue discomfort. Endoscope attachments can also collect tissue samples, remove polyps and small tumors, and extract foreign objects.

Technological advancements have supplemented the basic setup of flexible endoscopes with light-emitting diode illumination and device-acquired images that are electronically transmitted back to the video processor. These extra features enable the image to be sent to the monitor in high-definition (HD) format.

What Is the Modulation Transfer Function?

The modulation transfer function (MTF) is the magnitude response of the optical system to sinusoids of varying spatial frequencies. Sinusoid refers to the pattern of signal inputs when testing a lens, and are often approximated by square waves with hard edges. .

When analyzing the resolution of an optical system imaging line patterns, checkerboards or point objects are commonly used. The analysis of the image results in a measurement of the modulation transfer function and it describes how accurately the object’s spatial frequency content is transferred to the image.

MTF is a valuable indicator of accurate or efficient resolution because it accounts for blurriness and contrast across a wide range of spatial frequencies and image field points. It decreases as spatial frequency increases, corresponding to poor visibility of small structures. Meanwhile, at lower spatial frequencies, MTF approaches one, indicating the ability to visualize large structures.

The following variables and imperfections would affect the MTF:

  • Lens f/# or aperture size
  • Lens alignment, and tilts with respect to the image sensor
  • Imperfections in the individual lens elements
  • Vignetting an obstruction of the ray bundles

Why Gray Optics?

Gray Optics focuses on supporting original equipment manufacturers while transforming the company from a product engineering business to a fully integrated manufacturing provider. We also prioritize the continuous development and provision of medical devices and solutions to meet the needs of our customers. These include our precision assembly solution and minimally invasive medical devices.

Precision Assembly

Gray Optics’ production team is committed to transforming our customers’ designs into precision optical assemblies. This process starts with engineering prototypes in the product development phase and progresses to finished products in volume production. Our highly skilled and professional team of engineers and assembly technicians bring a wealth of knowledge and expertise that our customers have come to rely on and trust.

Moreover, Gray Optics’ facility has dedicated production work cells to assemble and test everything, from individual optical elements to complex optical assemblies. Our systems and processes are also based on and aligned with ISO 13485, for medical devices. These assets enable our team to consistently and reliably develop and test our clients’ optical products to the highest quality standards, from concept to manufacturing.

Among our precision assembly capabilities are the following:

  • Off-the-shelf (OTS) and custom optics assembly
  • Micro-optics and micro-optical assemblies
  • Fiber optic installation and polishing
  • Hermetic seals
  • Custom mechanical housing
  • Motion control (x,y,z stages) and automation systems
  • Illumination and detection modules
  • Traceability and inventory control
  • Complete optical systems with electronics and control software

Minimally Invasive Medical Devices

Gray Optics provides industry-leading product engineering and new product development services to fulfill the company’s mission of improving and saving lives. These products and services also help develop the next generation of advanced, minimally invasive surgical devices and tools.

A significant technological trend influencing the advancement of new, minimally invasive medical devices has been the miniaturization of high-resolution complementary metal oxide semiconductor (CMOS) image sensors. These sensors enable unique imaging techniques for better human body visualization. Furthermore, precision optics, mechanics, and light sources have allowed for the development and assembly of medical devices as small as 1 mm. in diameter.

The Best Optical Solutions From Gray Optics

At Gray Optics, we offer our customers a wide range of solutions to design, assemble, and test complex optical components and optics devices! We are committed to cultivating a collaborative environment and strengthening our team to support our mission of changing, improving, and saving lives by developing new optical products.

Contact us today for more information on precision optics for endoscopy, or talk to an expert for high-quality optical solutions tailored to your specific requirements!