Resized LCDs, A Proven Alternative

Resized LCDs, A Proven Alternative

Abstract

Lawrence E. Tannas, Jr.
President

Tannas Electronic Displays, Inc.
Orange, California

 

SID Display Applications Conference
October 24, 2007

 

Abstract: Since the first publications of resized LCDs in May of 1999 (Ref 1 & 2), they have been used in simulators, avionics and as replacements for custom LCDs, CRTs, ELDs and Plasma Panels. Resized LCDs have been qualified to aerospace requirements by three independent companies (Ref 3, 4 & 5). The COTS LCD glass is literally cut, or resized, to a new and smaller size and resealed without diminishing its performance.

Introduction: A new generation of LCD glass has been developed using the Tannas-Sized™ LCD process. New commercial-off-the-shelf (COTS) LCDs have been resized for many applications.
TED has been resizing LCDs for eight years. TED, a wholly-owned company of Tannas Electronics, has licensed the technology and is selling product to the industry at large. Custom-sized and custom-shaped LCDs never considered possible before have been demonstrated at SID, SPIE and other Symposia. The technology consists of taking a COTS LCD and physically cutting the glass, polarizer and circuit boards to a new size and resealing it without diminishing its original performance as specified by the LCD manufacturer. The TANNAS-SIZED™LCD process opens up a vast source of custom sizes for avionics, vehicular electronics, aerospace and industry at a fraction of the cost and lead time of custom-made displays. The resized LCDs are being used to replace custom-made LC, EL, PDP and CRT displays.

The cost of making a resized LCD by patented and proprietary methods is low and, typically, there is no NRE or minimum order. Nominal lead-time is six weeks.

Resizing Design Rules: The primary objective is to make the sizes needed to fit the task in a cost-effective manner. The first principle is to use as much of the original LCD as possible; secondly, be minimally invasive with all remaining parts. In the TANNAS-SIZED™ LCD process, the polarizers, TABs and LC material are preserved. Many other things could be changed but, thus far, this has not been found necessary.

The organization of the TABs, where used, dictates the most cost-effective way for resizing as shown in Slide 4. The glass does not need to be cut at the edges of a TAB, but the remaining TABs dictate the remaining number of active lines available for an image. Some LCDs use in-situ row drivers. In such cases, the horizontal cut can be made at any row. The LCD can be cut in either the horizontal or vertical direction or in both on the same display. Further, the corner away from the row and column drivers can be cut off in any manner without affecting the performance of the balance of the display as shown in Slide 5. This cut is preferably in a straight, diagonal line at any angle. The other corners can be diminished; but if cut into the active area of the display, the cut row or column lines will be lost.

The row and column circuit boards and circuits are primarily shift registers and can be cut off at the ends opposite the input with no consequence on the performance of the shift register or LCD. The input sync signals retain the same timing and the software remains the same. Obviously, the part of the image that would have been in the removed portion of glass is not displayed. The remaining viewable image is dictated by the remaining row- and column-driven lines and LCD glass. There may be other components on the circuit boards that will need to be moved before the down-stream ends of the circuit boards can be removed. However, this is most often not the case and the circuit boards can usually be cut along the same line as the LCD glass. This leads to a neat and cost-effective resized LCD. It is sometimes necessary to reorganize the column circuit board and reattach it to the TABs. If possible, this should be done without removing the TABs from the glass.

After resizing, the new seal is made narrower than the original seal. The detailed dimensions of the seal are shown in Slide 6. However, a seal narrower than 0.050” (1.27mm) has been found to be difficult to achieve.
Qualification Testing: The TANNAS-SIZED™ LCDs have been tested and they have successfully passed the commercial avionics ARINC FTCA/DO-160 Section Category B,

Severe Humidity Environmental test. This is a non-operating, ten-day, 24-hour cycle between 65°C and 38°C at 95% RH.

TANNAS-SIZED™ LCDs have been tested by J. Thomas and P. Lynes of General Dynamics, Canada, to the harsh land-military environment of the M1A2-SEP tank (Ref. 4). The resized LCD was made by Symbolic Displays, Inc., a Licensee of the TANNAS-SIZED™ LCD process to replace an EL display. It successfully passed a series of Mil Qualification tests.

TED has life-tested several resized LCDs. The longest test has been on a Sharp 13.3” LQ13x023 resized (on Feb. 04, 2003) to an 8”x8” display for the SID International Symposium of May 2003. Except during power outage and disconnection for travel, it has operated continuously ever since with no significant degradation. Ten resized NEC NL10276BC16-01s have been continually operated approximately one year each with no significant degradation.

TED has tested the resized seal in a very severe temperature cycle. Seals are tested from immersion in boiling water to wrapping in dry ice for five cycles over a ten-hour period. Everything fails except the LC material between the glass, the original manufacturer’s seal and the TED reseal.

As reported in a technical paper by David Craig, BAE Systems, (Ref. 3), under his direction, extensive testing was done on BAE-remanufactured LCDs. In Mr. Craig’s conclusion he states: “Our general conclusion from all the testing to date is that the resealed panel is as robust as the original; and that environment difficulties are more likely to be experienced with the other aspects of the remanufacturing process, for example protection of polarizers from UV and humidity.” Today, modern polarizers are much more resistant to UV and humidity than in the year 2000 at the time of the testing.

Size and Shape Options: LCDs can be resized in many ways and in a cost-effective way, as summarized in Slide 13. Resized cuts of 0.200 inches to 30 inches have been performed by TED and any one LCD can be resized many ways. The example of an LCD resized several ways as shown in Slide 12 is made from an NEC NL10276BC16-01 display. The advantages of multiple sizes made from the same COTS LCD is that one LCD model can be inventoried at the COTS cost for several end items. Further, they would all have the same interface electronics. The resizing can be done at the time the display is needed. Thus, the inventory cost is very low. This cost is in the realm of hundreds of dollars each compared to the inventory cost for custom displays that is in the range of thousands of dollars each.

The resizing of a 30-inch LCD is shown in Slides 14, 15 and 16. The resized 30-inch LCD is to replace an obsolete plasma panel in neon orange, Slide 16. The first application of a resized LCD was performed by Symbolic Displays, Inc., for an Apache Longbow Cockpit simulator, Slide 18. Of particular note is the F-35 8”x20” simulator display made by Driven Technologies, Inc., Slide 20. Inertial Aerospace Services, Inc., is developing a replacement D-size LCD using resized glass, Slide 21.

Summary: In every way, resized LCDs are proving to be viable, versatile, rugged and cost-effective. Further, they are significantly less expensive than custom LCD sizes presently made for the aerospace industry.

References:

1. Lawrence E Tannas, Jr. “ Resizing COTS AMLCDs for Avionics Application”, SID International Symposium, San Jose, May 1999;

2. Lawrence E Tannas, Jr., “AMLCD Resizing”, Presented at SPIE Conference 4362, 19 April 2001, Cockpit Displays VIII, Orlando, FL.

3. David M. Craig, “LCD cutting process: remanufacture of 4:3 aspect commercial into 1:1 avionic display”, Pro SPIE Vol. 4022 (2000) pp313-320

4. J. Thomas, P. Lynes, “Concept Validation for a Resized AMLCD Used in a Land- Mobile”, SPIE, Aug. 29, 2000;

5. Dr. Priya R. Brendale, Manager R&D, Interface Displays & Controls, SPIE Symposium on Defense & Security Display Technologies & Applications for Defense, Security and Avioinics, 12 April, 2007, Orlando, FL;