Elements of reliability | WX

Akito Nakao

2^nd Engineering Section
Engineering & Quality Control Department

Mr. Nakao's previous job was as an inspector of optical product parts at a small local factory. He joined Nikon Vision because he wanted to inspect finished products. Since then, Mr. Nakao has dedicated himself to the evaluation and inspection of telescopes and binoculars.

No compromises. Achieving the world's best.

Another role of the Engineering & Quality Control Department is the inspection of mass-produced finished products. At this stage, they inspect strictly whether the finished products have a quality standard that is good enough to be shipped to stores or not.

The basic inspection process for WX binoculars is the same as that for conventional binoculars.
The inspection starts by looking at outside scenery with WX binoculars. By looking at the scenery outside, any misalignment of optical axis or magnification differences between right and left tubes (magnification inequality) can be detected.
An experienced inspector will notice even a mere 1% of magnification inequality between right and left.

Every finished product is inspected. The image quality is checked first.

All lenses and prisms are examined for any possible scratches.

Next, the inspector looks through the binoculars from the objective lens side to view the interior of the body tubes, to check whether there are any scratches on the lenses and prisms incorporated inside.
The process involves shifting the focus of the inspector's eyes gradually to check both sides of the objective lenses, two prisms and the eyepieces.

After this, movable parts such as the central axis are moved to check operability and the exterior is examined for any scratches or damage.
Movable sections need to be operated repeatedly to check the combined accuracy of components that is required to clear the high performance standards. As Mr. Nakao says, “Like this, we inspect every binocular body meticulously by setting inspection items according to the product structure.”

“If parts are manufactured and composed as they are designed, the image quality that the engineer intended should be realised. However, in reality, there are tolerances (the differences between maximum dimensions and minimum dimensions within an allowable tolerance) for WX binoculars' parts, which generate a slight gap. The higher the number of lenses used, the larger the gap becomes. The engineer, Mr. Nishioka, his team and I considered a case when the maximum gap occurred, then discussed again and again how we could ensure achievement of the world's highest performance with stabilised reliability.”
Both Mr. Nakao and Mr. Ushikubo had the same thoughts: “We will manufacture the world's best product ever. Compromise is not acceptable.”