IPhone Defense Prompts New Debate

IPhone Defense Prompts New Debate

Steve Jobs's attempt to close the door on criticism of Apple Inc.'s (AAPL) latest iPhone ignited another debate: Are competing smartphones just as prone to reception problems or does Apple have a unique design flaw?

Mr. Jobs, in a news conference Friday, conceded that reception on the new iPhone 4--which has antennas housed in an exposed metal band around the phone's outside edge--can be degraded by the way a user holds the device. He also said the new iPhone drops slightly more calls than its predecessor.

But Mr. Jobs insisted that the problem, which occurs in areas with relatively weak cellular coverage, affects few users and is shared by other smartphones.

Apple showed videos of tests it conducted that indicated similar signal drops when phones by Research In Motion Ltd. (RIMM), HTC Corp. (HTCXF, 2498.TW) and Samsung Electronics (SSNHY, 005930.SE) are grasped by users.

His arguments were swiftly rejected by competitors, including RIM and Motorola Inc. (MOT), which said they have deliberately avoided Apple's approach of locating antennas on the phone's edge. Some other cellular-industry veterans also called Apple's antenna design a mistake, noting that it creates a uniquely sensitive spot on the lower left side that causes signals to degrade when touched with a hand or a finger.

'The proof of that [it being a flaw] is that it is so easily fixed,' said Martin Cooper, an engineer who helped lead Motorola's development of handheld cellphones in the 1970s. He noted that Apple has said adding a case largely addresses the attenuation issue, and predicted the company will find a simple way to isolate antennas in future models to eliminate the problem without a case.

Antenna experts agree with Mr. Jobs's statements that all cellphones are affected to some degree by a user's touch. For that reason, designers typically go to considerable lengths to minimize the antenna's contact with the hand, in some cases adding duplicate antennas to reduce the potential signal weakening that engineers call attenuation.

But some experts and competitors questioned the validity of Apple's tests of competing products, which it posted on its website. They said the science behind the tests wasn't clear and the visual evidence--a drop in coverage bars on the phones' screens--isn't very meaningful since the software that measures signals isn't standardized.

Jason Lohn, a professor of electrical engineering at Carnegie Mellon University, said the competing phones Apple used in its videos 'don't have the antenna's bare metal exposed to the hand, so I'd be surprised if the effect of the hand would be as pronounced as it was on the iPhone 4.'

Sanjay Jha, Motorola's co-CEO, said Sunday his company's tests showed that the amount radio signals decline on the iPhone 4 when a user's hands touch the sensitive spot on the phone's edge is significantly greater than the attenuation when other smartphones are held.

Not all experts think the iPhone 4's design is a bad idea. Haim Harel, president and founder of wireless chip maker Magnolia Broadband, said Apple may have created a design 'breakthrough' if it can perfect external antennas for cellphones.

The approach, which saves space for other functions in a phone, was also praised by Franz Birkner, CEO of antenna technology maker Rayspan Corp. 'But the challenge of innovation is it inevitably comes with risk,' he said.

An Apple spokeswoman declined to comment Sunday, referring back to Mr. Jobs's comments Friday. The CEO said the problem had been 'blown out of proportion' by the media, stating that about one half of 1% of users had complained about it. Still, Apple offered free cases or 'bumpers' to alleviate the problem.

Concern about the iPhone 4's reception was elevated last week when Consumer Reports said it couldn't recommend the product after conducting its own reception tests.

After Mr. Jobs's presentation Friday, the organization called the offer of free cases 'a good first step' but said it isn't a long-term solution, and that it still didn't recommend the phone.

Attensity360, which studies consumer sentiment on blogs and other social media, said Mr. Job's press conference appeared to be a qualified success. In the two days after the press conference, the amount of negative conversation about the iPhone 4 on such English-language sites fell 30% compared with the prior seven days, the firm found.

But some consumers aren't satisfied. Jason Wong, a 29-year-old college math lecturer in Southern California, said he plans to return his iPhone 4. 'I feel it is kind of stupid to have paid $200 for a phone that I can't hold in the natural way,' he said.

Don Clark / Niraj Sheth / Geoffrey A. Fowler

蘋果為“天線門”辯解引發新爭論

喬

布斯(Steve Jobs)企圖終止外界對蘋果公司(Apple Inc.)最新版iPhone的批評﹐卻引發了另一場爭論：其它智能手機也像iPhone 4一樣易於出現信號接收問題嗎？還是iPhone存在獨有的設計缺陷？

Geoffrey A. Fowler/The Wall Street Journal

在週五的新聞發佈會 上﹐喬布斯承認新iPhone 4的信號接收性能可能會受到用戶持機方式的影響而有所減弱。他還說新iPhone掉線的機率僅略微高於前幾款iPhone。iPhone 4的天線被放置在環繞機身的外部金屬環中。

但喬布斯堅持稱這一問題發生在手機信號相對較弱的區域﹐僅對極少數用戶有影響﹐並且其它智能手 機也存在這種問題。

Geoffrey A. Fowler/The Wall Street Journal

蘋果公司展示的測 試視頻顯示其它公司的手機也會受到持機方式的影響。

蘋果公司展示了測試視頻。它所進行的測試表明﹐用戶手握Research In Motion Ltd.(簡稱RIM)、宏達國際(HTC Corp.)和三星電子(Samsung Electronics)的手機時也出現了類似的信號減弱現象。

他的言論迅速遭到競爭對手的反駁。RIM和摩托羅拉(Motorola Inc.)等公司說它們在設計手機時謹慎地避免採取蘋果的方式﹐避免把天線置於手機邊緣。手機行業的部分資深人士也稱蘋果的天線設計有誤﹐並指出這一設計 讓手機的左下方產生了一個獨特的敏感點﹐用戶用手或手指接觸這個點時會導致信號減弱。

於 上世紀70年代幫助領導摩托羅拉公司手機開發業務的工程師庫珀(Martin Cooper)說﹐這種設計是一種缺陷﹐證據在於它很容易修正。他指出﹐蘋果公司曾表示添加一個保護套能夠在很大程度上解決信號減弱的問題﹐並估計蘋果公 司將找到一種簡單的隔離天線的方式﹐以便在未來的機型上不用保護套也能消除這一問題。

天線專家同意喬布斯的說法﹐即所有手機在一定程度上 都會受到用戶接觸的影響。因此﹐設計者通常儘量減少天線與手的接觸﹐某些情況下還會增加副天線以減少潛在的信號減弱現象。

蘋果公司在其網 站上公佈了對競爭機型的測試。但部分專家和競爭對手對蘋果公司測試的有效性表示質疑。他們說﹐不清楚這些測試是否科學﹐而且手機屏幕上顯示的信號強度減弱 這一表面證據的意義也不太大﹐因為測量信號強度的軟件並不統一。

卡內基-梅隆大學(Carnegie Mellon University)電子工程教授羅恩(Jason Lohn)說﹐蘋果在其視頻中使用的競爭手機天線裸露的金屬並沒有暴露在手裡﹐所以﹐假如手對它的影響會和對iPhone 4的影響一樣明顯的話﹐會大出我的意料的。

摩托羅拉聯席首席執行長傑哈(Sanjay Jha)週日說﹐摩托羅拉的測試顯示﹐當使用者的手接觸手機邊緣的敏感部位時﹐iPhone 4的無線電信號衰減量比其他智能手機拿在手裡時的衰減量要明顯大的多。

並非所有的專家都認為iPhone 4的設計不好。無線芯片生產商Magnolia Broadband總裁、創始人阿雷爾(Haim Harel)說﹐假如蘋果能夠將手機的外部天線做到完美﹐可能就在設計上取得了重大突破。

這種設計為手機中的其他功能節省了空間﹐也受到 了天線技術生產商Rayspan Corp.首席執行長伯克納(Franz Birkner)的讚揚。他說﹐不過﹐創新行為的挑戰在於它不可避免地會伴隨著風險。

蘋果發言人週日拒絕置評﹐只是再次提到喬布斯上週五 的說法。喬布斯當時說問題被媒體“夸大”了﹐說只有約0.5%的用戶對此進行了投訴。不過﹐蘋果提供了免費的手機套來解決天線問題。

上週 ﹐《消費者報告》(Consumer Reports)說﹐在它進行了信號接收測試後﹐無法推薦這款產品。對iPhone 4信號接收問題的擔憂隨之升級。

喬布斯上週五的新聞發佈會之後﹐《消費者報告》稱提供免費手機套是邁出了良好的第一步﹐不過說這並非長遠 的解決之道﹐它仍不推薦這款產品。

研究博客和社交媒體上消費者情緒的Attensity360說﹐喬布斯的新聞發佈會看起來取得了相當大 的成功。該公司發現﹐在新聞發佈會後的兩天中﹐英文網站上有關iPhone 4的負面討論數量較發佈會前七天減少了30%。

不過﹐一些消 費者並不滿意。29歲的南加州數學講師Jason Wong說﹐他計劃退掉買的iPhone 4。他說﹐我感覺花200美元買了一部我無法用合乎常理的方式拿著的手機真是太愚蠢了。

Don Clark / Niraj Sheth / Geoffrey A. Fowler

Japan's newest billboards come with facial recognition

很早以前就知道這玩意

Japan's newest billboards come with facial recognition, predicting what you should buy next

Posted: 07/16/2010

• Joey Rogers

TOKYO - Face recognition technology in Japan is changing the way advertisers do business.

Imagine walking through your local mall or shopping center seeing billboards that advertise to your exact interests. Everywhere you walk, electronic signs flash products that cater to your individual tastes.

A Japanese electronics company, NEC, is creating a facial-recognition system that will be inserted into billboards to identify the sex and age of people that pass by. The new billboards will display general advertisements that are suitable for each specific person.

Each billboard will have a camera and flat-panel monitor built in. When a consumer walks by, the billboard uses the new facial-recognition system to determine gender and age to within ten years. The information is sent to an internal computer which would than pick a generalized advertisement to display. The longer a person stands in front of the sign's camera, the more accurate his or her specific advertisement is.

The facial-recognition system is called the Next Generation Digital Signage Solution,and it has become an advertiser's dream. NEC's vice president of strategic alliances, Takeshi Yamamoto, says the technology will allow advertisers to develop more successful campaigns.

"For digital signage that relies on generating revenue by selling advertising, there has always been a need for advertising agencies to know who is watching,” says Yamamoto.

The one concern about this new technology is that it's an invasion of privacy on the individual consumer. NEC officials insist that anonymity is a main priority and facial images would not be stored.

"NEC's Ad Measurement technology was developed to be totally anonymous. While the technology captures data as it relates to gender and age, it does not capture or store any footage or information as it pertains to a specific individual,” says Yamamoto.

This new technology is currently being tweaked and tested in Japan, and is expected to have test trials in America before the end of the year.

Information from abcnews.com and telegraph.co.uk

Copyright 2010 Scripps Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

iPhone 4 case

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Animal Autopsies in Gulf Yield a Mystery

Animal Autopsies in Gulf Yield a Mystery

Nicole Bengiveno/The New York Times

Dr. Brian Stacy, a veterinary pathologist who works for the National Oceanic and Atmospheric Administration, is conducting necropsies on sea turtles found dead in the Gulf of Mexico, to begin the process of determining what killed them. More Photos »

By SHAILA DEWAN

Published: July 14, 2010

GAINESVILLE, Fla. — The Kemp’s ridley sea turtle lay belly-up on the metal autopsy table, as pallid as split-pea soup but for the bright orange X spray-painted on its shell, proof that it had been counted as part of the Gulf of Mexico’s continuing “unusual mortality event.”

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Under the practiced knife of Dr. Brian Stacy, a veterinary pathologist who estimates that he has dissected close to 1,000 turtles over the course of his career, the specimen began to reveal its secrets: First, as the breastplate was lifted away, a mass of shriveled organs in the puddle of stinking red liquid that is produced as decomposition advances. Next, the fat reserves indicating good health. Then, as Dr. Stacy sliced open the esophagus, the most revealing clue: a morsel of shrimp, the last thing the turtle ate.

“You don’t see shrimp consumed as part of the normal diet” of Kemp’s ridleys, Dr. Stacy said.

This turtle, found floating in the Mississippi Sound on June 18, is one of hundreds of dead creatures collected along the Gulf Coast since the Deepwater Horizon oil rig exploded. Swabbed for oil, tagged and wrapped in plastic “body bags” sealed with evidence tape, the carcasses — many times the number normally found at this time of year — are piling up in freezer trucks stationed along the coast, waiting for scientists like Dr. Stacy, who works for the National Oceanic and Atmospheric Administration, to begin the process of determining what killed them.

Despite an obvious suspect, oil, the answer is far from clear. The vast majority of the dead animals that have been found — 1,866 birds, 463 turtles, 59 dolphins and one sperm whale — show no visible signs of oil contamination. Much of the evidence in the turtle cases points, in fact, to shrimping or other commercial fishing, but other suspects include oil fumes, oiled food, the dispersants used to break up the oil or even disease.

The efforts to finger a culprit — or culprits — amount to a vast investigation the likes of which “CSI” has never seen. The trail of evidence leads from marine patrols in Mississippi, where more than half the dead turtles have been found, to a toxicology lab in Lubbock, Tex., to this animal autopsy room at the University of Florida in Gainesville. And instead of the fingerprint analysis and security camera video used in human homicides, the veterinary detectives are relying on shrimp boat data recorders and chromatographic spectrum analysis that can tell if the oil residue found in an animal has the same “chemical signature” as BP crude.

The outcome will help determine how many millions BP will pay in civil and criminal penalties — which are far higher for endangered animals like sea turtles — and provide a wealth of information about the little-known effects of oil on protected species in the Gulf.

“It is terribly important to know, in the big scheme of things, why something died,” said Moby Solangi, the director of the Institute for Marine Mammal Studies in Gulfport, Miss., where the initial turtle necropsies and some dolphin necropsies were performed.

“We might be doing what we can to address the issues of today and manage the risk,” he said. “But for tomorrow, we need to know what actually happened.”

Searching for a Smoking Gun

In a laboratory at Texas Tech University in Lubbock, Jennifer Cole, a graduate student, was slicing a precious chunk of living dolphin tissue into 0.3-millimeter sections.

Supervised by Céline Godard-Codding, an endangered species toxicologist, Ms. Cole was studying cytochrome P450 1A1, an enzyme that breaks down hydrocarbons.

Tissue samples are one of the only ways to learn more about toxins in marine mammals and sea turtles, whose protected status limits the type of studies that can be done — researchers cannot do experiments to determine how much oil exposure the animals can withstand.

Oil — inhaled or ingested — can cause brain lesions, pneumonia, kidney damage, stress and death. Scientists working on the BP spill have seen oil-mired animals that are suffering from extreme exhaustion and hyperthermia, with the floating crude reaching temperatures above 130 degrees, Dr. Stacy said.

Far less is known about the effects of dispersants, either by themselves or mixed with oil, though almost two million gallons of the chemicals have been used in the BP spill.

Studies show that dispersants, which break down oil into tiny droplets and can also break down cell membranes, make oil more toxic for some animals, like baby birds. And the solvents they contain can break down red blood cells, causing hemorrhaging. At least one fresh dolphin carcass found in the Gulf was bleeding from the mouth and blowhole, according to Lori Deangelis, a dolphin tour operator in Perdido Bay.

Investigators plan to take skin and mouth swabs, stomach contents, slices of organ tissue and vials of bile from animals that have died and test them for disease and hydrocarbons, as well as for dispersants, before a final report on the cause of death is written. But no samples have yet been sent to labs, because scientists are still evaluating what type of tests will prove most useful.

Jacqueline Savitz, a marine biologist with Oceana, an ocean conservation group, said there was no excuse for any delay in testing.

“It’s absolutely urgent that it should be done immediately,” she said, because the findings could influence response measures like BP’s experimental use of dispersants underwater.

In the meantime, at places like the Texas Tech institute, the oil spill has set off a mad scramble to fill in the gaps in knowledge. In one laboratory, jars of BP crude in various stages of weathering await analysis to determine their relative toxicity. In another lab, graduate students paint precise amounts of oil on incubating duck eggs. Tanks of fiddler crabs awaited a shipment of Corexit 9500, the dispersant being used by BP in the Gulf.

In the end, Dr. Godard-Codding said, scientists will not find a single smoking gun. The evidence — results of laboratory tests, population counts, assessments of how well oil-drenched animals survive after rehabilitation — will all be circumstantial.

Suspicions Fall on Shrimpers

When Lt. Donald Armes of the Mississippi Marine Patrol heard about the rash of dead sea turtles littering the state’s shores, his first thought was not of oil but of shrimp boats.

“Right off the bat, you figure somebody’s gear was wrong,” he said recently, after patrolling for shrimpers in the Mississippi Sound, a few days before floating islands of oil forced officials to close it. By gear, Lieutenant Armes meant turtle excluder devices, which shrimp trawlers are supposed to have. Without them, trawls can be one of the biggest dangers for turtles, which can get trapped in the nets and drown. The devices provide an escape hatch. Another kind of shrimp net, called a skimmer, is not required to have an excluder device — instead, the length of time the skimmers can be dragged is limited by law to give trapped turtles a chance to come up for air.

When shrimp season began in Mississippi on June 3, the marine patrol inspected all the boats and found no violations involving the excluders, Lieutenant Armes said. But on June 6, 12 dead turtles were found in Mississippi in a single day. Similar spikes have occurred when parts of Louisiana waters were opened to shrimpers, and since most of the waters in the spill area have closed, the turtle deaths have subsided.

Shrimpers emerged as a prime suspect in the NOAA investigation when, after a round of turtle necropsies in early May, Dr. Stacy announced that more than half the carcasses had sediment in the airways or lungs — evidence of drowning. The only plausible explanation for such a high number of drowning deaths, he said, was, as he put it, “fisheries interaction.”

Environmentalists saw the findings as confirmation of their suspicions that shrimpers, taking advantage of the fact that the Coast Guard and other inspectors were busy with the oil spill, had disabled their turtle excluder devices.

The devices are so contentious that Louisiana law has long forbidden its wildlife and fisheries agents to enforce federal regulations on the devices. Last month, Gov. Bobby Jindal vetoed legislation that would have finally lifted the ban, citing the “challenges and issues currently facing our fishermen.” By contrast, Mississippi officials strengthened turtle protections by decreasing the allowable tow time for skimmers, posting observers on boats, and sending out pamphlets on turtle resuscitation.

Officials in both states say that turtles die in shrimp season even when shrimpers follow the law, from boat strikes and other accidents. They also say there have been far fewer shrimpers working since the spill, in part because many have hired out their boats to BP. That should mean fewer, not more, turtle deaths.

But there has also been illegal activity. In Louisiana, agents have seized more than 20,000 pounds of shrimp and issued more than 350 citations to commercial fishermen working in waters closed because of the oil spill. In Mississippi in June, three skimmer boats were caught exceeding legal tow times — one just hours after the shrimper had been given a handout explaining that the maximum time had been reduced, Lieutenant Armes said.

As for the piece of shrimp that Dr. Stacy found lodged in the turtle’s throat during the necropsy, it, too, pointed to shrimpers. A turtle is normally not quick enough to catch shrimp, Dr. Stacy said. Unless, of course, it is caught in a net with them.

Diagnosing Difficulties

In the necropsy lab in Gainesville, Dr. Stacy was slitting open the turtle’s delicate windpipe, looking for traces of sediment, a tell-tale sign of drowning. He finds none there, so he examines a crinkled papery membrane barely recognizable as lungs. Nothing.

“Drowning can be a difficult diagnosis,” he said. He has requested data that will show the level of commercial fishing in the area. But, he cautioned, “A lot of times our evidence is fairly indirect.”

In a sense, the necropsies so far have posed more questions than answers, demonstrating how oil has become just another variable in an already complex ecosystem. Late in June, a dolphin examined at the Institute for Marine Mammal Studies in Gulfport showed signs of emaciation, but its belly was full of fish, suggesting that it may have gorged itself after a period of difficulty finding food.

Another dolphin, its ribs broken, was hit by a boat, a catastrophe that dolphins are normally nimble enough to avoid. The veterinarian, Dr. Connie Chevis, found a tarlike substance in the dolphin’s throat. The substance will be analyzed to see if it is oil, but one theory is that the animal could have been disoriented by oil exposure, which can have a narcotic effect, rendering it incapable of avoiding a boat strike. Ms. Deangelis said the dolphins on her recent tours have been “acting like they’ve had three martinis.”

The results raise questions about oil’s indirect effects. Is crude, for example, responsible for what anecdotal reports say is a steep increase in turtles in Mississippi and Louisiana waters? The population of Kemp’s ridleys has been rebounding thanks to years of protective measures. But some scientists have speculated that the spill is driving wildlife toward the coast, crowding areas where there is more boat traffic and setting the stage for fatal accidents.

In a normal year, one or two turtles might get snagged on the hooks of recreational fishermen at the piers. Now, the marine mammal institute in Gulfport is caring for 30 such turtles, a possible indication that they are desperate for food. In recent weeks, Dr. Chevis said, she has begun to see elevated white blood cell counts and signs of pneumonia in rescued turtles, both of which are symptoms of oil exposure, but could easily have other explanations.

In Gainesville, Dr. Stacy returned the jumbled remains of the turtle that ate the shrimp to its plastic wrapper and sent it back to the freezer. There, it will be stored indefinitely, just one piece of evidence among thousands.

Digital Light Processing (DLP) DLP投影儀

【開發故事】DLP投影儀（一）：堅持20年不放棄的男人（上） 　　美國德克薩斯州最大的城市達拉斯。在這個有著牧牛和牛仔 歷史的城市裡，一項技術宣告誕生。這項技術在很長時間裡“養在深閨人未識”，甚至一度處於行將消亡的境地。然而，憑借一個 男人長年累月的苦斗，成就了時至今日的一項無人不曉的核心技術…… (詳見全文) 【開發故事】DLP投影儀（二）：堅持20年不放棄的男人（下） 　　Larry最初的工作，是制作有機械構造的微鏡陣列。這 種微鏡陣列是將金屬覆膜的薄塑料板載於硅制芯片上而成。這是Larry自己的創意。他們首先試制出了用銻對硝酸纖維素…… (詳見全文) 【開發故事】DLP投影儀（三）：對，是數字式的（上） 　　采用可動的微鏡來控制光的行進方向的器件。用電來控制微 鏡的角度，並將其應用到打印機上，這是在美國德州儀器（Texas Instruments，TI）進行微鏡器件研究的Larry J.Hornbeck的目標…… (詳見全文) 【開發故事】DLP投影儀（四）：對，是數字式的（下） 　　首先，不管怎麼說，傾斜角度是最重要的因素。例如，可在±10 度的角度內傾斜。此前的懸臂式微鏡器件無法傾斜如此大的角度。另外，此次的傾斜角度可不受周圍環境變化及時序變化影響地一直保持恆定…… (詳見全文) 【開發故事】DLP投影儀（五）：糟糕，微鏡不動了（上） 　　不知道是誰在小聲提醒。大原為了讓微鏡的故障不那麼明顯，開 始頻繁地切換場景進行演示。因為切換場景的話，吸附在底板上的微鏡有可能復原…… (詳見全文) 【開發故事】DLP投影儀（六）：糟糕，微鏡不動了（下） 　　令大原擔心的理由另外還有一個。這就是，大原剛剛回到達拉斯，他 在達拉斯的直屬上司就跳槽走了。而那是一個十分理解DMD用DSP重要性的人，大原就是在他的要求下才來到達拉斯的…… (詳見全文) 【開發故事】DLP投影儀（七）：要買請耐心等待（上） 　　為了開拓微鏡器件“DMD”的用途，美國德州儀器的工作 人員在美國內外四處奔忙。當然，在日本的展會上，德州儀器也大張旗鼓地進行了展示。在1995年大阪舉辦的Electronics Show上，該公司就展出了實際采用DMD的顯示器及投影儀。沖著這種投影儀，有3個男人千裡迢迢從東京趕了過來…… (詳見全文) 【開發故事】DLP投影儀（八）：要買請耐心等待（下） 　“這是真機？還是實物模型？”“不是在騙人吧？”“背後有 什麼機關吧？”在特設會場參觀了試制機的人，大多留下了這樣的感想。另外，很多人表示希望接觸到真機。顯然他們不相信這麼小的投影儀 真的能工作…… (詳見全文) 【開發故事】DLP投影儀（九）：哪裡不好，請告訴我（上） 　　憑借普樂士推出的超小型前投式投影儀，使人們對DLP技 術的認知度不斷提高。接下來美國TI的最終目標是應用在背投電視上。在這方面，聯手開發的合作方仍然是日本企業。美國TI 的工作人員走訪擁有豐富的電視機開發經驗的企業進行游說。然而，對方提出的嚴格要求卻遠遠超出了TI的預想…… (詳見全文) 【開發故事】DLP投影儀（十）：哪裡不好，請告訴我（下） 　　在松下電器總部的會議室裡，TI的工作人員與松下電器的 技術團隊相互對峙。TI方面的負責人是當時全權負責DLP背投電視業務開發的Dale Zimmerman。松下電器方面，則 有電視機業務的負責人及許多開發人員參加…… (詳見全文) 【開發故事】DLP投影儀（十一）：這種“白”還是初次見（上） 　　美國TI的Larry J. Hornbeck殫精竭慮開發出了微鏡器件“DMD”。DMD順利地在前投式投影儀上得到采用，來自日本國內電視機廠商的關注度也與 日俱增，在背投電視上的應用也逐步取得了進展。在商用多屏顯示器方面，還有一家果敢地向實用化發起挑戰的公司…… (詳見全文) 【開發故事】DLP投影儀（完）：這種“白”還是初次見（下） 　　自TI的Larry J. Hornbeck開始研發DMD起到現在已經過去27年了。這項技術最初只不過是眾多未來的技術之一

Wikipedia

Digital Light Processing (DLP) is a trademark owned by Texas Instruments, representing a technology used in some TVs and video projectors. It was originally developed in 1987 by Dr. Larry Hornbeck of Texas Instruments.

DLP is used in DLP front projectors (small standalone projection units) and DLP rear projection television.

DLP, along with LCD and LCoS, are the current display technologies behind rear-projection television, having supplanted CRT rear projectors. These rear-projection technologies compete against LCD and plasma flat panel displays in the HDTV market.^[1]

The single-chip version of DLP and 3LCD are the two main technologies used in modern color digital projectors, with the two technologies being used in over 95% of the projectors sold in 2008.

DLP is also one of the leading technologies used in digital cinema projection.

In March 2008, TI announced the initial production of the DPP1500 chipset, which are micro projectors to be used in mobile devices. Availability for final products would show up in the market early 2009.

Contents [hide] 1 Digital micromirror device 2 Color in DLP projection 2.1 Single-chip projectors 2.1.1 The color wheel "rainbow effect" 2.2 Three-chip projectors 2.3 Light source 2.3.1 Metal-halide lamps 2.3.2 LED-based DLPs 2.3.3 LASER-based DLPs 3 Digital cinema 4 Manufacturers and market place 4.1 Pros 4.2 Cons 4.3 DLP, LCD, and LCoS rear projection TV 5 See also 6 References 7 External links

Digital micromirror device

Main article: Digital micromirror device

In DLP projectors, the image is created by microscopically small mirrors laid out in a matrix on a semiconductor chip, known as a Digital Micromirror Device (DMD). Each mirror represents one or more pixels in the projected image. The number of mirrors corresponds to the resolution of the projected image (often half as many mirrors as the advertised resolution due to wobulation). 800x600, 1024x768, 1280x720, and 1920x1080 (HDTV) matrices are some common DMD sizes. These mirrors can be repositioned rapidly to reflect light either through the lens or on to a heat sink (called a light dump in Barco terminology).

Rapidly toggling the mirror between these two orientations (essentially on and off) produces grayscales, controlled by the ratio of on-time to off-time.

Color in DLP projection

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There are two primary methods by which DLP projection systems create a color image, those utilized by single-chip DLP projectors, and those used by three-chip projectors. A third method, sequential illumination by three colored light emitting diodes, is being developed, and is currently used in televisions manufactured by Samsung. Yet another method, color LASERs, is currently in use by Mitsubishi in their LASERVUE products.^[2]

Single-chip projectors

Interior view of a single-chip DLP projector, showing the light path. Light from the lamp enters a reverse-fisheye, passes through the spinning color wheel, crosses underneath the main lens, reflects off a front-surfaced mirror, and is spread onto the DMD (red arrows). From there, light either enters the lens (yellow) or is reflected off the top cover down into a light-sink (blue arrows) to absorb unneeded light. Top row shows overall components, closeups of 4-segment RGBW color wheel, and light-sink diffuser/reflection plate on top cover.

In a projector with a single DLP chip, colors are produced either by placing a color wheel between a white lamp and the DLP chip or by using individual light sources to produce the primary colors, LEDs or LASERs for example. The color wheel is divided into multiple sectors: the primary colors: red, green, and blue, and in many cases secondary colors including cyan, magenta, yellow and white. The use of the secondary colors is part of the new color performance system called BrilliantColor which processes the primary colors along with the secondary colors to create a broader spectrum of possible color combinations on the screen.

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 observer sees a composite "full color" image. In early models, this was one rotation per frame. Now, most systems operate at up to 10x the frame rate.

The color wheel "rainbow effect"

A single-chip projector alternates between colors and produces separate red, green, and blue images when displaying a moving image, or in this case, illuminating a moving hand.

DLP projectors utilizing a mechanical spinning color wheel may exhibit an anomaly known as the “rainbow effect.” This is best described as brief flashes of perceived red, blue, and green "shadows" observed most often when the projected content features high contrast areas of moving bright/white objects on a mostly dark/black background. The scrolling end credits of many movies are a common example, and also in animations where moving objects are surrounded by a thick black outline. Brief visible separation of the colours can also be apparent when the viewer moves their eyes quickly across the projected image. Some people perceive these rainbow artifacts frequently, while others may never see them at all.

This effect is caused by the way the eye follows a moving object on the projection. When an object on the screen moves, the eye will follow the object with a constant motion, but the projector will display each alternating color of the frame at the same location, for the duration of the whole frame. So, while the eye is moving, it will see a frame of a specific color (red for example). Then, when the next color is displayed (green for example), although it gets displayed at the same location overlapping the previous color, the eye will have moved toward the object's next frame target. Thus, the eye will see that specific frame color slightly shifted. Then, the third color gets displayed (blue for example), and the eye will see that frame's color slightly shifted again. This effect is not perceived only for the moving object, but the whole picture.

The effect varies with the rotational speed of the color wheel and the frame refresh rate of the video signal. There is a maximum rotational speed limit for the wheel, typically 10,000 to 15,000 RPM. Video framerate is usually measured in frames per second and must be multiplied by 60 to find the wheel speed, whereas 60 frames/sec equals 3,600 frames/minute. If the color wheel spins 4 times per frame, it is rotating at a speed of 14,400 RPM. (Projector specifications often list the wheel speed at specific framerates as 2x, 3x, 4x, etc.)^[3][4] Increasing the video refresh rate to 85 frames per second does not necessarily further reduce the rainbow effect since this rate would increase the wheel speed to 20,400 RPM, potentially exceeding the safe limits of wheel rotation and requiring the projector to drop back to 3x speed, at 15,300 RPM.

Multi-color LED-based and LASER-based single-chip projectors are able to eliminate the spinning wheel and minimize the rainbow effect since the pulse rate of LEDs and LASERs are not limited by physical motion.

Three-chip projectors

A three-chip DLP projector uses a prism to split light from the lamp, and each primary color of light is then routed to its own DLP chip, then recombined and routed out through the lens. Three chip systems are found in higher-end home theater projectors, large venue projectors and DLP Cinema projection systems found in digital movie theaters.

According to DLP.com, the three-chip projectors used in movie theaters can produce 35 trillion colors, which many suggest is more than the human eye can detect. The human eye is suggested to be able to detect around 16 million colors, which is theoretically possible with the single chip solution. However, this high color precision does not mean that three-chip DLP projectors are capable of displaying the entire gamut of colors we can distinguish (this is fundamentally impossible with any system composing colors by adding three constant base colors). In contrast, it is the one-chip DLP projectors that have the advantage of allowing any number of primary colors in a sufficiently fast color filter wheel, and so the possibility of improved color gamuts is available.

Light source

The main light source used on DLP-based rear screen projection TVs is based on a replaceable high-pressure mercury-vapor metal halide arc lamp unit (containing a quartz arc tube, reflector, electrical connections, and sometimes a quartz/glass shield), while in some newer DLP projectors high-power LEDs or LASERs are used as a source of illumination.

Metal-halide lamps

For metal-halide lamps, during start-up, the lamp is ignited by a 5000 volt pulse from a current-regulating ballast to initiate an arc between two electrodes in the quartz tube. After warmup, the ballast's output voltage drops to approximately 60 volts while keeping the relative current high. As the lamp ages, the arc tube's electrodes wear out and light output declines somewhat while waste heating of the lamp increases. The mercury lamp's end of life is typically indicated via an LED on the unit or an onscreen text warning, necessitating replacement of the lamp unit.

Older projectors would simply give a warning that the lamp life had expired but would continue to operate. Newer projectors will not power up until the lamp is replaced and the lamp hours are reset. Most devices include a lamp hours reset function for when a new lamp is installed, but it is possible to reset a projector to continue to use an old lamp past its rated lifespan.

When a metal-halide lamp is operated past its rated lifespan, the efficiency declines significantly, the lightcast may become uneven, and the lamp starts to operate extremely hot, to the point that the power wires can melt off the lamp terminals. Eventually, the required startup voltage will also rise to the point where ignition can no longer occur. Secondary protections such as a temperature monitor may shut down the projector, but a thermally overstressed quartz arc tube can also crack and/or explode, releasing a cloud of hot mercury vapor inside and around the projector. However, practically all lamp housings contain heat-resistant barriers (in addition to those on the lamp unit itself) to prevent the red-hot quartz fragments from leaving the area.

LED-based DLPs

The first commercially-available LED-based DLP HDTV was the Samsung HL-S5679W in 2006, which also eliminated the use of color wheel. Besides long lifetime eliminating the need for lamp replacement and elimination of the color wheel, other advantages of LED illumination include instant-on operation and improved color, with increased color saturation and improved color gamut to over 140% of the NTSC color gamut. Samsung expanded the LED model line-up in 2007 with products available in 50", 56" and 61" screen sizes. For spring 2008, the third generation of Samsung LED DLP products are available in 61" (HL61A750) and 67" (HL67A750) screen sizes.

Ordinary LED technology does not produce the intensity and high lumen output characteristics required to replace arc lamps. The special patented LEDs used in all of the Samsung DLP TVs are PhlatLight LEDs, designed and manufactured by US based Luminus Devices. A single RGB PhlatLight LED chipset illuminates these projection TVs. The PhlatLight LEDs are also used in a new class of ultra-compact DLP front projector commonly referred to as a "pocket projector" and have been introduced in new models from LG Electronics (HS101), Samsung electronics (SP-P400) and Casio (XJ-A series). Home Theater projectors will be the next category of DLP projectors that will use PhlatLight LED technology. At InfoComm, June 2008 Luminus and TI announced their collaboration on using their technology on home theater and business projectors and demonstrated a prototype PhlatLight LED based DLP home theater front projector. They also announced products will be available in the marketplace later in 2008 from Optoma and other companies to be named later in the year.

Luminus Devices PhlatLight LEDs have also been used by Christie Digital in their DLP-based MicroTiles display system^[5]. It is a modular system built from small (20 inch diagonal) rear projection cubes, which can be stacked and tiled together to form large display canvasses with very small seams. The scale and shape of the display can be any size, only constrained by practical limits.

LASER-based DLPs

The first commercially-available LASER-based DLP HDTV was the Mitsubishi L65-A90 LASERVUE in 2008, which also eliminated the use of a color wheel. Three separate color LASERs illuminate the digital micromirror device (DMD) in these projection TVs, producing a richer, more vibrant color palette than other methods. See the laser video display article for more information.

Digital cinema

Main article: Digital cinema

DLP is the current market-share leader in professional digital movie projection, largely because of its high contrast ratio and available resolution as compared to other digital front-projection technologies. As of December 2008, there are over 6,000 DLP-based Digital Cinema Systems installed worldwide.^[6]

DLP projectors are also used in RealD Cinema for 3-D films.

Manufacturers and market place

Texas Instruments remains the primary manufacturer of DLP technology, which is used by many licensees who market products based on T.I.'s chipsets. The Fraunhofer Institute of Dresden, Germany, also manufactures Digital Light Processors, termed Spatial Light Modulators, for use in specialized applications. For example, Micronic Laser Systems of Sweden utilizes Fraunhofer's SLMs to generate deep-ultraviolet imaging in its Sigma line of silicon mask lithography writers.

DLP technology has quickly gained market share in the front projection market and now holds roughly 50% of the worldwide share in front projection. Over 30 manufacturers use the DLP chipset to power their projectors.

Pros

• Smooth (at 1080p resolution), jitter-free images.
• Perfect geometry and excellent grayscale linearity achievable.
• Usually great ANSI contrast.
• No possibility of screen burn-in.
• Less "screen-door effect" than with LCD projectors.
• DLP rear projection TVs generally have a smaller form factor than comparable CRT projectors.
• DLP rear projection TVs are considerably cheaper than LCD or plasma flat-panel displays and can still offer 1080p resolution.
• The use of a replaceable light source means a potentially longer life than CRTs and plasma displays (this may also be a con as listed below).
• The light source is more-easily replaceable than the backlights used with LCDs, and on DLPs is often user-replaceable.
• New LED and LASER DLP TVs and projectors eliminate the need for lamp replacement.
• Using two projectors, one can project full color stereoscopic images using polarized process (because beams can be polarized).
• Lighter weight than LCD and plasma televisions.
• Unlike their LCD and plasma counterparts, DLP screens do not rely on fluids as their projection medium and are therefore not limited in size by their inherent mirror mechanisms, making them ideal for increasingly larger high-definition theater and venue screens.
• DLP Projectors can process up to 7 separate colors giving them strong color performance
• DLP projectors do not suffer from “Color Decay” often seen with LCD projectors in which the image on the screen turns yellow after extended periods of usage.

Cons

• Some viewers are bothered by the "rainbow effect," explained above.
• Not as thin as LCD or plasma flat-panel displays (although approximately comparable in weight), although some models as of 2008 are becoming wall-mountable (while still being 10" to 14" thick)^[7]
• Replacement of the lamp / light bulb. The average life span of a TV light source averages 2000-5000 hours and the replacement cost for these range from $99 – $350, depending on the brand and model. After replacing the bulb a few times the cost can easily exceed the original purchase price of the television itself. Newer generations units use LEDs or LASERs which effectively eliminates this issue, although replacement LED chips could potentially be required over the extended lifespan of the television.
• Some devices may have fan noise.
• Dithering noise may be noticeable, especially in dark image areas. Newer (post ~2004) chip generations have less noise than older ones.
• Error-diffusion artifacts caused by averaging a shade over different pixels, since one pixel cannot render the shade exactly.
• Response time in video games may be affected by upscaling lag. While all HDTVs have some lag when upscaling lower resolution input to their native resolution, DLPs are commonly reported to have longer delays. Newer consoles such as the Xbox 360 do not have this problem as long as they are connected with HD-capable cables.^[8]
• Reduced viewing angle as compared to direct-view technologies such as CRT, plasma, and LCD.

DLP, LCD, and LCoS rear projection TV

The most similar competing system to DLP is known as LCoS (liquid crystal on silicon), which creates images using a stationary mirror mounted on the surface of a chip, and uses a liquid crystal matrix (similar to a liquid crystal display) to control how much light is reflected.^[1] DLP-based television systems are also arguably considered to be smaller in depth than traditional projection television.

See also

• Comparison of display technology
• 3LCD
• CRT projector
• Flat panel display
• Handheld projector
• Large-screen television technology
• Inflatable movie screen
• Laser video display
• LCD projector
• LED projector
• Liquid crystal on silicon
• OLED
• Plasma display
• SED

References

1. ^ ^{a b} "4 styles of HDTV". CNET.com. 2007-03-13. http://www.cnet.com/4520-7874_1-5108443-3.html. Retrieved 2007-08-13.
2. ^ http://www.laservuetv.com
3. ^ Discussion of color wheel speed as 2x, 3x per frame. http://www.projector.com/resources/projectordisplaytypes.php
4. ^ Book cite on rainbow effect and color wheel rotations per frame, pp 217–218, Newnes Guide to Television and Video Technology, By K. F. Ibrahim, Eugene Trundle, Edition: 4, illustrated, Published by Newnes, 2007, ISBN 0750681659, ISBN 9780750681650, 586 pages, Direct link to cited material via Google Books: http://books.google.com/books?id=90GZPA-hCuMC&pg=PA218&dq=DLP+projector+wheel+4x&ei=tW80SpfFBprAM57izJ4E#PPA217,M1
5. ^ "Luminus Devices’ PhlatLight LEDs Illuminate Christie MicroTile’s New Digital Canvas Display". Businesswire. http://www.businesswire.com/portal/site/home/permalink/?ndmViewId=news_view&newsId=20100609006222&newsLang=en. Retrieved 2010-63-28.
6. ^ TI (2008-02-15). "“European Cinema Yearbook”". Mediasalles. http://www.mediasalles.it/yearbook.htm. Retrieved 2008-02-15.
7. ^ http://www.futurelooks.com/420-CES-2007-Home-Entertainment-Products-Highlights.html?page=4
8. ^ "HDTVs and Video Game Lag: The Problem and the Solution.". AVS Forum. 2005-07-11. http://www.avsforum.com/avs-vb/showthread.php?t=558125. Retrieved 2007-08-13.

External links

• DLP Demo
• BOXLIGHT Corp. DLP White Paper https://system.netsuite.com/core/media/media.nl?id=6485&c=492114&h=25551c21675d994130e9&_xt=.pdf
• DLP projectors vs LCD projectors Easy guide on DLP and LCD technology in projectors and how they compare

'Perfect Citizen'

U.S. NEWS
U.S. Plans Cyber Shield 'Perfect Citizen'

The U.S. plans a program, "Perfect Citizen," to detect cyber assaults on companies and government agencies running critical infrastructure such as the electricity grid and nuclear power plants.

• More Coverage: National Security Agency

• Cybercrime Risks Still Growing

• Vote: What do you think of the program?

• Readers React: 'The name screams Orwell'

Perfect Citizen is a program run by the United States National Security Agency and Raytheon to develop a system of sensors to detect cyber attacks on critical infrastructure computer networks.^[1]

References

1. ^ "U.S. Program to Detect Cyber Attacks on Infrastructure". The Wall Street Journal. 2010-07-07. http://online.wsj.com/article/SB10001424052748704545004575352983850463108.html?mod=WSJ_hpp_MIDDLETopStories. Retrieved 2010-07-07.