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Hall Sensor Color Wheel

Dust Free Solution for Image Projection

Materion is developing a new color wheel that offers a solution to improved image projection in dusty environments.  In areas where air quality may be poor, such as developing countries or busy cities, projector operation can be affected by dust particles.  Our new color wheel, with its innovative hall sensor motor, is able to overcome this problem and offer a cost advantage.

The Challenge

The current system uses a photo sensor to read the TIM (time index mark) to recognize the color filter segment position.  However, if any particles or dust appear on the photo sensor, it will not work properly and cannot create a signal (the waveform) to the controlling IC on the DLP projector board. This failure would in turn cause the color wheel to stop and not be initialed.

The Materion Solution

Our solution is to provide a component for the color wheel that can create the signal with a hall sensor.  With this in place, the projector will not be sensitive to particles or dust.  By replacing the photo sensor and time index mark with a hall sensor, it allows the digital micro mirror device (DMD) IC to recognize the position of each color filter segment or phosphor segment

How It Works

A DMD chip has on its surface several hundred thousand microscopic mirrors arranged in a rectangular array which correspond to the pixels in the image to be displayed. The DLP chip is synchronized with the rotating motion of the color wheel so that the green component is displayed on the DMD when the green section of the color wheel is in front of the lamp. The same is true for the red, blue and other sections. The colors are thus displayed sequentially at a sufficiently high rate that the viewer sees a composite "full color" image.

Advantages of the Hall Sensor Color Wheel

There are several benefits derived from using the hall sensor color wheel including:

  • Replaces photo-sensor & TIM resulting in system cost saving
  • Provides dust-free solution that adds value to projector operation
  • Integrates phosphor wheel design, enhances the solid state illumination (SSI) module value

More About Materion Color Wheels

As one of the the world’s largest manufacturer of optical components, Materion provides an array of products to support your image projection needs.  Our new hall sensor color wheel joins our family of “Wheel” products (ColorWheelTM, WhisperWheelTM, LumiWheelTM,SilentWheelTM). When a dusty environment, such as that found in the education projector market, threatens the optimal operation of your equipment – consider the hall sensor color wheel as a solution. For more information, contact Vivian Zhang, Product Line Manager,