Thursday, December 6, 2012


The headline is, “Mitsubishi Drops DLP Displays: Goodbye RPTVs Forever”. Like 3D, projection TV got off to a bad start. The first widely available projection TV was the Kloss Videobeam (Henry Kloss was the K in KLH). It was based on a single color CRT (driven very hard) and projected on a specialty curved screen. The product had a number of difficulties. Being front projection, it had to be viewed in the dark. Even so it was dim. The curved screen had multiple problems as well. It could not be cleaned with conventional cleaners without leaving a lasting residual in the image on the screen… and it was added expense.

One by one, these problems all were fixed; but not by Kloss as they were immediately displaced from the market by the Japanese with a 3 tube projector design. Due to the loss of energy and light caused by the shadow mask in a color tube, a monochrome tube can be 5 times as bright as a color tube. Having three monochrome tubes (a red, green and blue) in a projection set made for an image that was 15 times brighter. Improved optics did away with the curved screen and switching from a front projection to a rear projection format meant that it could be viewed in a lit room; RPTV was born.

These improvements eliminated the initial problems with projection TV but created new ones as well. Early RPTVs were difficult to align and the sets in consumers’ homes were frequently not aligned. Also the lenticular front screens did a great job of spreading out the light from left to right but had little effect distributing light vertically. Many projection sets were used as public displays in bars and placed up high where the primary light from the display went over the heads of the viewers. The result was in your neighbor’s house and in public, when you saw an RPTV, it usually looked terrible. One other aspect remained as well, driving a CRT very hard meant that it necessarily had a short life span, significantly shorter than consumers were used to.

By the mid 1990’s, after 20 years of fine tuning, projection TVs had gotten to the point where consumers did have a hard time telling them from direct view CRTs. In consumer surveys taken at the time, many consumers reported buying 45” and 55” direct view sets even though direct view was never sold in these sizes; they were obviously projection sets. In addition to improving the screen and making alignment much easier, RPTV makers had incorporated clever folded optical paths, decreasing the RPT set thicknesses from feet to inches. Further, as HDTV with the transition to 16:9 was in the offing, RPTV looked forward to a bright future as CRTs were fundamentally ill-suited for the wider format.

Also beginning in the 90’s, new RPTV image engines were being developed. Most famously, TI developed the DLP, a micro-mirror technology using an external light source. Also Liquid Crystal on Silicon (LCOS) showed promise. The first DLP sets were expensive, and in-part to hold down costs, it was designed as a field sequential color set with a color wheel, as were the first color TV set designs from CBS. Of course, introducing a mechanical component into what had been a purely solid state device meant that these sets had maintenance issues. As with the original Kloss Videobeam, these single imager designs were rapidly dropped for 3 imagers. However even the improved design had maintenance issues as well as the high performance light source tended to have a life of only 2-3 years. This meant that the set still had to be actively maintained. Though makers took to packaging an extra bulb in the sets that they shipped, Consumers were frequently not aware of this and had to spend $200 to replace their bulbs the first time they burned out. Even so, replacing the bulb could be tricky as oils from your hand could cause early failure of the bulbs and even when the first bulb was used and installed correctly, the owner was still faced with making significant purchase every few years to maintain their set.

In spite of all of these issues, RPTV sales grew as they were actually a great value compared with large sized Plasma at the time. However, as Plasma got cheaper and LCDs grew in size and capability, RPTVs value story diminished. The loss of value was exacerbated by, in my opinion, a failure to tell a good marketing story to consumers. TI made some direct efforts to promote DLP but their commercials were ineffective and lacked a clear message to the consumer about why RPTV sets were better for them. Even today, with the HDTV transition having well passed, the average size LCD set being sold is only about 38”, much smaller than what is needed to fully take advantage of HDTV resolution. There have been significant pushes by the set industry as a whole on each new feature, frequently this in opposition to getting the consumer the proper sized set. Though both LCD and Plasma offer very thin sets, thinner than what can be made in RPTV, most American homes are not at a loss for space. American consumers really need to have larger sets and telling them this should have been the mission of the RPTV industry.

Mitsubishi positioned itself as “the large screen TV Company” and was the last maker of RPTV. However, lacking the marketshare and marketing dollars to make an impact, it was only a matter of time. The RPTV story has several lessons for other technologies as well. Being introduced with obvious visual problems, it took a couple of decades for the technology to shake off its initial bad impression. Plasma still suffers from a perception of image burn-in. Some of the initial 3D sets had bad flicker issues.

Most RPTV sales were in the US; in the beginning, virtually all RPTV sales were in the US. Though I sometimes criticize pyrrhic marketshare battles, there is significant value to a technology having a global appeal. Though the US is unique in being both wealthy and having large homes, the public information display/digital signage market is global. Significant numbers of RPTVs were bought here as public information displays, maybe as much as half in its early years. The set makers, in general never recognized this as a significant market until recently but the market has always been there. If RPTV had built some momentum in the early years it could have been doing fine in digital signage as well. But of course, in the US with the ADA requirement of nothing sticking out from the wall by more than 4” any RPTV installation has to be either high up or floor standing both of which are not particularly well suited to a retail environment.

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