Silicon Light

Q. What is Grating Light Valve technology?

A. Silicon Light Machines’ Grating Light Valve device is based on a diffractive optical MEMS comprised of a series of tiny ribbons on the surface of a silicon chip. When electrical voltages are applied, the ribbons move by a fraction of a wavelength - creating a dynamic, tunable grating that precisely varies the amount of light that is diffracted or reflected.

Q. Is Grating Light Valve an electrically controlled grating used in a spectrometer?

A. No. The GLV does have a grating structure but is not designed to separate wavelengths. The GLV controls the light intensity with a specific wavelength.

Q. Why is Grating Light Valve a linear array?

A. Because its pixel modulation rate is high enough. With one-dimensional scanning, the GLV-based system can create a tremendously high-resolution image. The pixel count in the scanning direction is virtually infinite and step-and-repeat motion is not required.

Q. What are the applications of Grating Light Valve technology?

A. Due to the versatility of the GLV technology, Silicon Light Machines offers innovative products that solve the problems of OEM customers in a variety of markets. The GLV device is currently used for spatial light modulation in high-resolution displays and high-performance computer-to-plate equipment. In addition, the characteristics of the GLV device are practical for a variety of applications in image/data recording like maskless lithography.

Q. How can the same device be used for all the applications?

A. The basic technology is readily adaptable to cover a broad range of wavelengths. It was designed for near-IR print and visible display applications, and has proven effective by several leading manufacturers for these applications. Silicon Light Machines has also adapted the ribbon dimensions to accommodate the shorter wavelengths of maskless lithography. Besides utilizing different wavelengths, each application requires different specifications. Silicon Light Machines provides each customer with a custom product to meet their demanding requirements.

Q. Are diffractive MEMS devices reliable?

A. Silicon Light Machines’ diffractive MEMS are extremely reliable. The ribbons’ total range of motion is very small (~0.2 micrometers), and there are no points of contact between moving parts. In addition, the GLV device can remain stable over a long period of exposure to high power laser illumination. We have tested our MEMS devices for over a trillion cycles, and we could not measure any onset of fatigue.

Q. How does the GLV device differ from tilting mirror MEMS?

A. In many tilting mirror designs, the MEMS device is etched out of a silicon substrate, leaving a raised mirror on a bearing surface. The movement and positioning of the mirror may require precise control electronics and accurate feedback mechanisms. In operation, this type of device will "sweep" light at constant amplitude from the source to the destination fiber. In other words, the light amplitude is constant; the output angle is variable. In contrast, the GLV device is an addressable diffraction grating that can serve as a simple mirror in the static state, or a variable grating in the dynamic state. This unique approach offers significant advantages in terms of speed, accuracy, reliability and manufacturability over the common "tilting mirror" MEMS structures.