Color TFT LCD Module with Embedded DRAM Frame-Memory - NEC

NEC LCD Technologies is prototyping the Color TFT LCD module with embedded DRAM frame memory system. The new LCD module implements a combination of NEC’s value integrated TFT-LCD (VIT) technology and low-temperature poly-silicon (LTPS) TFT technology.

NEC Color TFT LCD Module with DRAM Frame-Memory

Embedding the graphics frame memory into an LCD module is one solution as it enables preservation of the image signal transferred from the system as one set of screen data. As a result, the graphics frame memory enables screen output by reading the data preserved in the graphics frame memory when the same screen is viewed. This realizes a significant reduction in power consumption due to reduced signal communication between the display device and the system.

Hideki Asada, NEC LCD Technologies, stated:

The market is already eagerly awaiting the advancement of system-on-glass LCDs as they will eliminate the need to develop LSI chips, thereby shortening development cycles significantly, and allowing us to bring the right products to our customers and the markets faster than ever before…

Embedding the frame memory onto the glass substrate is a completely new breakthrough in system-on-glass LCD technology, and will enable significant reductions in display power consumption. This kind of new technology demonstrates the leading innovation that drives NEC LCD Technologies, and provides all of our customers with a competitive edge…

Key features of the new Color TFT LCD Module:

• Successful design of a system LSI onto the glass substrate of the screen, utilizing a record-breaking 400,000 transistors in the peripheral circuits. The LCD integrates the peripheral circuits, including the frame memory system that incorporates a 230k-bit DRAM and a front-end picture decoder, a picture encoder, 6-bit DAC, and a controller
• Adoption of a RGB horizontal stripe for the pixel arrangement enables high density, a polychrome display, and optimization of cell layout of the graphics frame memory, simultaneously. This kind of pixel arrangement enables greater minimization of the circuit area on the glass substrate, which generally increases along with pixel density, as compared with RGB vertical stripe arrangements
• Adoption of NEC’s proprietary graphical data compression / decompression technology, smart pixel-data codec (SPC), enables a reduction in the amount of memory required to store the data of one screen image by two thirds that required by original data that does not employ any kind of codec, thereby contributing to a reduction in circuit area and power consumption
• The newly-developed controller enables simultaneous and independent access for writing and reading in graphics frame memory, and achieves a data transfer rate of approximately 30 frames per second, enabling smooth display of a variety of digital movie contents

The new Color TFT LCD module is suitable for portable devices, such as smartphones, PDAs, portable multimedia players (PMPs) and personal navigation devices (PNDs). The progression of a networked information society is concurrently creating a demand for display devices that provide a range of diverse features simultaneously, including high density, high luminance, polychrome display, small size, short depth, light weight, and low power consumption.

Source: NEC Color TFT LCD Module with DRAM Frame-Memory