Micro Lens Arrays

WHERE THE OPTICS SIT

THE LED PRINT HEAD

OKI moved into optoelectronics with LED printing and has been building the optical path ever since. Where a laser print head tracks a beam back and forth across the drum, an LED head flashes the entire line at once and never moves — and the lens array is what images that light across the few centimetres to the drum. Fewer moving parts means fewer component failures, simpler maintenance and repair, and a markedly smaller machine.

OKI LED print head compared with a laser print head

HOW IT WORKS

AN IMAGE FORMED IN SPACE, NOT ON A SURFACE

A lens array sits between the light source and the target. Unlike a fibre-optic plate, which forms its image right at the end face, a lens array forms an image in space — like a camera lens.

LIGHT ACROSS THE WHOLE LINE

A line of LEDs illuminates the full width in a single flash, rather than one beam tracking back and forth across the drum.

FOCUSED THROUGH THE ARRAY

The lens array images that light onto the target. Because the image forms in space rather than at a surface, clearance can be left on both sides of the lens.

CLEARANCE ON BOTH SIDES

Several millimetres of gap is what makes the design practical: nothing to foul the optical surface, and resolution as high as 1200 dpi.

WHY IT MATTERS

OPTICS THAT LET THE WHOLE HEAD STAY STILL

In the optical path

Forms an image in space, like a camera lens
Several millimetres of clearance either side of the lens
Resolution as high as 1200 dpi
Moisture does not present a problem

In the finished device

No moving parts in the print head
A full line exposed at once, not scanned
Varying intensity for every dot, for finer detail and colour depth
Heads that stay still, so the device can be far smaller

THE LED PRINT HEAD

TELL US ABOUT YOUR APPLICATION

AN IMAGE FORMED IN SPACE, NOT ON A SURFACE

OPTICS THAT LET THE WHOLE HEAD STAY STILL

TALK TO OKI ABOUT MICRO LENS ARRAYS