Fergason Patent Properties LLC | System Synchronized Brightness Control

1. Why do we need SSBC?

Conventional LCD designs offer only a limited dynamic range, resulting in both low contrast, limited gray level resolution, and poor viewing angles for dark or night time images, and low impact bright images.

2. What are the features and benefits of SSBC?

SSBC enables blacker blacks and brighter brights, increasing the dynamic range, viewing angle, and contrast ratio of LCD flat panels. In addition the technology modifies the input video image to improve the number of gray levels used in the display, increasing detail and gray resolution. Improved video performance is achieved without increasing power requirements. Specific benefits include:

Dramatic improvement of dark frame contrast and viewing angle. The modulation of backlight intensity to control frame brightness allows the input video to be modified to increase the number of gray levels in the dispay. In conventional LCDs, the number of gray levels used in dark or nighttime images is limited to control overall image brightness.

Dramatic increase in peak brightness. SSBC enables the operation of the backlight at peak brightness levels for short time periods to boost up the luminance for peak frame impact.

LCD video performance that approaches the movie experience. SSBC extends the dynamic range of brightness available from a LCD, matching the performance more closely to that of a cinema experience.

Power and performance optimization options. The SSBC algorithm can further incorporate monitoring of the ambient light level in the viewing environment to optimize the dynamic range for viewing in bright or dark ambient conditions. Both high performance and power conservation modes can be incorporated.

3. Can the features and benefits of SSBC be easily demonstrated?

Many of the SSBC licensees offer commercial television sets where the SSBC feature can be turned off and on by the consumer, permitting a side by side comparison of performance. FPP can demonstrate the impact of SSBC using two off-the-shelf Panasonic 15 inch television sets, operating at identical factory presets. The Panasonic control panel allows the user to turn the SSBC feature on or off to enable a side by side comparison. FPP has prepared a demo DVD with video clips and test patterns. In addition, the backlight duty cycle control signal is monitored on the scope, allowing the observer to simultaneously compare the picture quality as well as the backlight brightness, with and without SSBC. FPP cannot dynamically monitor the gamma modulation.

SSBC demo showing the impact of SSBC on video quality

4. What types of displays can use SSBC?

SSBC can be integrated into any display system where the display light source and the pixel modulation are independent. The prime example is a conventional AMLCD where a fluorescent backlight is modulated independently by a transmissive LCD panel. Conventional microdisplay based projections systems are another example. CRT, Plasma, and OLED displays cannot use SSBC.

5. How does SSBC work?

Three components make up the SSBC system: a digital processor, a variable backlight, and a passive display. A digital controller or computer processes the input video signal to characterize the brightness and color of the pixel content and uses algorithms to determine the ideal backlight level and color and modifies the input video pixel information to increase the number of gray levels. The computer sends an output control signal to the backlight to set the backlight level and color and sends the processed video signal to the LCD for display.

6. Is it difficult to integrate SSBC into a LCD TV or monitor?

It is relatively simple to integrate SSBC into an LCD. VLSI circuitry needs to be modified or added to perform the frame brightness characterization algorithm, output signals to control backlight brightness, and adjust system gray level parameters to enhance the dynamic range of the image. A high dimming ratio commercially available backlight inverter should be used to take maximum advantage of the effect. An example of a suitable backlight and inverter is the VHB LCD Backlight Series from Landmark Technology. http://www.landmarktek.com/. Several FPP licensees make LCD modules and projection engines available with integrated SSBC control. Contact LG.Philips LCD, Epson, and Chinontec to find out more about these products.

7. How can I find out more about SSBC