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​How a Design Battle Between Chip Engineers Led to Polaroid’s Revolutionary SX-70 Digital camera

In a single nook stood the defending champion, Texas Devices. Within the different stood the challenger, Fairchild Semiconductor. The referee, decide, promoter, and solely spectator was Polaroid. In rivalry was the contract for the electronics of Polaroid’s secret mission—a pioneering product launched in 1972 because the SX-70, a digital camera finally bought by hundreds of thousands of individuals.

Because the embodiment of actually automated immediate pictures, the SX-70 fulfilled a long-held dream of Edwin Land, founding father of Polaroid Corp., Cambridge, Mass. Important to this “level and shoot” functionality was a brand new movie—one that might develop whereas uncovered to mild and so get rid of the tear-away covers of earlier Polaroid movies. Additionally very important had been refined electronics to regulate all single lens reflex (SLR) digital camera features, together with flashbulb choice, publicity management, mirror positioning, begin of print growth, and ejection of print. These circuits had been divided into three modules, one every for motor, publicity and logic, and flash management. On the ultimate depend, some 400 transistors had been used.

This text was first printed as “The battle for the SX-70.” It appeared within the Might 1989 problem of IEEE Spectrum. A PDF model is offered on IEEE Xplore. The diagrams and pictures appeared within the unique print model.

But this sophisticated system had to slot in a package deal the scale of Land’s jacket pocket, he decreed—a constraint that meant using ICs. However as Polaroid couldn’t fabricate ICs, the success of its SX-70 mission lay within the fingers of outsiders.

The flash management contract was given to Common Electrical Co. Then in 1971, when GE dropped out of the IC enterprise, it was issued to Sprague Electrical Corp., in addition to to Fairchild Semiconductor Corp. of Palo Alto, Calif., and Texas Devices Inc. of Dallas, Texas. Solely Fairchild and Sprague ended up producing flash controllers.

Unbiased contracts to develop the motor and publicity management modules went to Fairchild and TI. The motor management module contained a linear management IC, an NPN motor drive transistor, and a discrete PNP dynamic braking transistor, and gave the designers little bother. The publicity management module was a unique story.

The grand problem

Included within the publicity management had been three ICs (early Fairchild variations had 4). The publicity timer used the present output of a silicon photodiode to manage how lengthy the shutter blades remained open. The delay-timing circuit generated 4 intervals: a delay of 40 milliseconds earlier than the shutter opened; the time the shutter remained open earlier than the flash was fired; the period of the flash; and the utmost publicity time given sure ambient lighting. The facility management IC drove the solenoids and motor management unit. And this all needed to match on a board that match right into a 27-by-95-by-2-millimeter house, minus a central gap for the digital camera lens.

Electrical noise was a significant stumbling block. The photocell, as an illustration, working with as little as 15 picoamperes, needed to keep its state in an setting during which the motor, the solenoids, and the firing of the flash lamps drew amperes of present. Designers had been to take steps like inserting a delay between the discharge of the solenoids and the beginning of the photocell-timed publicity; redesigning circuitry on the ability provide line to reject noise from the motor; growing the voltage distinction between logic highs and lows, so noise spikes would now not masquerade as bits; and together with a low-pass filter.

Because it was 1969, there have been no semicustom ICs, gate array expertise was in its infancy, and solely primitive packaging was accessible—normal twin in-line packages (DIPs) had been no less than 0.125 inch thick—whereas logic and energy transistors couldn’t but share the identical piece of silicon. And Polaroid needed to purchase this publicity controller for US $5.75.

What buddies are for

Polaroid chairman Land and TI chairman Patrick Haggerty had been outdated buddies. On a weekend journey many years earlier than the SX-70 mission, that they had mentioned how electronics may someday make a very one-step digital camera doable. The thought was to work on this dream collectively as quickly because the expertise arrived. So it got here as no shock when TI was charged with growing the digital camera’s publicity management board. Land was relying on TI for a fail-safe design, primarily based on analog circuitry and confirmed expertise and due to this fact dependable, moderately priced, and able to being produced on schedule.

Polaroid additionally requested Fairchild, which it seen because the nation’s chief in IC expertise, to sort out a design that might push the cutting-edge. Fairchild’s model was to be digital and extremely built-in, even to combining energy transistors with logic on one chip. To Polaroid the strategy regarded dangerous, however its engineers had been excited by its prospects. Nonetheless, some inside Polaroid thought the Land-Haggerty relationship made nonsense of utilizing anybody however TI.

In the dead of night

The R&D contracts had been awarded in 1969, and the opponents went to work, each with the identical handicap: incomplete data. Fearing that Kodak Corp. may enter the moment digital camera enterprise, Polaroid needed no leaks—a lot in order that it talked about neither the brand new movie nor the truth that at one level the digital camera was redesigned as an SLR—and stored the design groups from seeing a prototype of the digital camera. (Though TI’s then government vp, the now-retired Fred Bucy, noticed an illustration of the early, non-SLR SX-70 in 1969, he stated nothing about it to the corporate’s engineers.) Mentioned Peter Carcia, an engineer on the SX-70 mission and nonetheless with Polaroid: “They’d little or no to work with”—solely stacks of specs.

white wiring diagram on blue-grey background with gates, outputs, and other features indicated, plus words "systems diagram M3 phase II G717566

When it contracted with Fairchild and TI to develop the electronics for the SX-70 digital camera, Polaroid Corp. offered this timing diagram together with 30 pages of different design specs, reliability necessities, and take a look at data. It signifies sequences of occasions for the 4 totally different modes of operation a completely computerized digital camera required. Desk 1 signifies features for taking images in ambient mild, Desk 2 covers flash operation, Desk 3 calls out the sequence of occasions that’s triggered when a brand new movie pack is put in and its protecting cowl have to be ejected, and Desk 4 describes the operations that happen when a pack of movie is used up.

Polaroid engineers recall that hundreds on the electronics had been described merely as inductive, and that particulars of the battery provide had been imprecise as a result of a brand new battery was being concurrently designed.

“We didn’t inform them whether or not a load on the electronics was from a solenoid or a relay, simply that it was an inductive load,” recollects Seymour Ellin, now a senior technical supervisor at Polaroid.

“Since we had been making our personal battery [designed concurrently], we couldn’t inform them what the battery provide could be,” stated Carcia. “I’d inform them ‘I need you to design a circuit, however I received’t inform you what the ability supply will likely be,’ and they’d take a look at me unusually.”

Polaroid needed no leaks—a lot in order that it talked about neither the brand new movie nor the truth that at one level the digital camera was redesigned as an SLR.

Even worse was the “Y” delay—which Polaroid engineers informed IEEE Spectrum got here from the “why” response given Fairchild and TI engineers at any time when they questioned one specification: the brief delay earlier than beginning the publicity, after the consumer pressed the button. This pause was to permit the mirror (which in an SLR digital camera displays the picture seen via the lens to the viewfinder) to cease vibrating after it snapped out of the best way of the movie to be uncovered. However that was greater than Polaroid needed to disclose. The sources of the noise downside had been left obscure, and its extent understated, stated Clark Williams, then a TI design engineer. “That motor pulled 3 amps of present and put out a wealthy spectrum of noise that performed havoc with our circuits,” he stated. (He’s now a design supervisor at Dallas Semiconductor Corp. in Dallas, Texas.)

The TI workforce, unable to base a breadboard on Polaroid’s diagrams alone, despatched two engineers and a number of other technicians to Cambridge to work in somewhat non-public room there. Every time they wanted to check their breadboard, they might hand it over to Polaroid engineers, who would carry it to a different room and finally report again that, say, a sure sign wanted adjustment or a sure part didn’t perform. The TI engineers would make a number of changes, then the breadboard was carried off for one more take a look at. This to-and-fro-ing went on for six months, whereas, stated Michael Callahan, a senior TI design engineer who’s presently government vp of engineering at Crystal Semiconductors Corp. in Austin, Texas: “We might have achieved the work in two weeks if that they had allow us to signal nondisclosure agreements.”

Designing in Dallas

A preliminary spherical had disenchanted each IC groups. In 1969, earlier than Polaroid had firmed up many SX-70 particulars, it began each TI and Fairchild growing easy publicity management chips. This early effort, stated Polaroid engineers, was additionally used to develop and take a look at their working relationship with Fairchild. However the SX-70 mission modified a lot, significantly with its redefinition as an SLR digital camera, that Polaroid determined to begin over. Callahan and Ken Buss, now a senior member of the technical workers at TI, recall a gathering in Dallas at which the TI engineers proudly demonstrated the working circuits—solely to have Polaroid ignore them and announce its new necessities.

“That made our chips immediately out of date,” Buss stated. At Fairchild, too, enthusiasm flagged. Coincidentally, each corporations quickly after underwent a company restructuring, however whereas the adjustments at Fairchild benefited its SX-70 workforce, these at TI practically price it all the things.

The TI designers, as an alternative of working straight with Polaroid, had been informed to report back to the Assembled Features Group. Missing both chip growth or manufacturing services of its personal, the Group contracted with the IC designers’ division to develop three chips—a photocell amplifier to find out the proper publicity, a chip to regulate the motor and deal with dynamic braking, and a chip to deal with timing, depend the movie used, and serve different features—and with one other division to fabricate the chips. The association additional filtered the already restricted data from Polaroid.

hand holding one circuit board between thumb and forefinger, two other circuit boards of similar size on table

Three totally different designs for the SX-70 publicity management electronics had been produced. Fairchild Semiconductor Corp.’s model (prime) went into cameras in 1972 and 1973—discover the polyimide movie used to connect the ICs to the board. Texas Devices Inc. produced its ceramic board (middle) throughout 1972, then redesigned, and received the manufacturing contract away from Fairchild with a circuit board that used miniDIP IC packaging (backside).

That left the Group itself with the job of designing the circuitry that might tie the ICs collectively. Its engineers used 13 discrete transistors, 17 laser-trimmed thick-film resistors, and a photodiode, aspiring to mount them on a printed-circuit board. Administration as an alternative mandated a ceramic substrate basically as a result of, stated one TI design engineer, the Group reported to the identical supervisor as TI’s Hybrid Thick-Movie Group, which had extra capability.

“We knew we couldn’t meet the price targets with a ceramic substrate,” he stated. The ceramic, the valuable steel conductors, and the labor all price an excessive amount of for the substrate to function something greater than a prototype “to allow us to get all of the circuitry in a small space.” And when the design grew from 3/4 sq. inch to 4 or 5 sq. inches (from 5 to 25 or 32 sq. centimeters), the engineer recalled, he and the opposite designers predicted main manufacturing issues and urged doing a extra digital redesign with a printed-circuit board. However administration “wouldn’t pay attention,” he stated.

TI’s ceramic-based design did, nevertheless, carry out to Polaroid’s specs, and it went into manufacturing in late 1972. However it was certainly a nightmare. First, at $100 a unit, it was nowhere close to the $5.75 price aim. And manufacturing issues had been super, particularly with the large and due to this fact fragile ceramic substrate. For example, stated TI design engineer Norm Culp: “We needed to take a chip, alloy it to a Kapton movie service [a high temperature plastic foil], then wire bond the chip to the Kapton service, then encapsulate the chip. The Kapton movie carriers had been then examined individually, then reflowed onto the ceramic substrate.”

Yield was about 1 p.c, and that one in 100 generally cracked on its method to Polaroid.

Furthermore, stated Culp, reflow-soldering chip carriers to the substrate induced microcracks within the ceramic, and for some time TI inspected each half for the failings. Then one engineer realized that heating all the substrate as an alternative of simply the half to be reflow-soldered would scale back the microcracks, which, nevertheless, confirmed up in different elements of the method. Yield was about 1 p.c, and that one in 100 generally cracked on its method to Polaroid.

Polaroid did order a number of hundred of those ceramic modules to get the SX-70 to market. However it wasn’t in any respect proud of them. Mentioned Ellin, “TI, basically, failed to satisfy the price goal.”

Competing in California

In the meantime, engineers at Fairchild had been additionally operating into difficulties, however technical ones solely. Early within the design course of, Fairchild’s company restructuring moved the R&D engineers out of their remoted laboratory into working divisions, making for higher communication with manufacturing, which “resolved loads of issues,” stated Howard Murphy, a senior member of the Fairchild analysis workers and the mission director for the SX-70 electronics.

“We designed a die that had round 20 flip-flops on it, in all probability a brand new excessive in IC complexity at the moment.”—Howard Murphy, Fairchild

One design downside was excessive temperature. Murphy recalled that the warmth of the heavy currents drawn by the motors and the solenoids affected the management logic circuitry, which then needed to be redesigned to work at greater temperatures—the specs indicated 40 °C. One other hurdle was the picture circuit. It needed to trip after 20 seconds, in order that photos could possibly be taken in dim mild of about 0.06 candela per sq. foot (0.65 candela per sq. meter), though the circuit design workforce wasn’t absolutely conscious of the explanation for this on the time. The circuit additionally needed to be very small and devour only a few milliamperes. “So we designed a die that had round 20 flip-flops on it, in all probability a brand new excessive in IC complexity at the moment,” Murphy remembered.

Frank Perrino, a Fairchild product supervisor, first turned concerned within the SX-70 mission in Might 1971, when he oversaw its transfer into manufacturing. He recalled that the designers had been then engaged on 4 chips—a driver for the motor and solenoids, a timing chip, and the photodiode and photodiode amplification chips that later turned one bipolar CMOS IC. The cube had been to be mounted straight on an irregularly formed 1-by-4-inch ceramic substrate beforehand metalized on each side with state-of-the-art strains and areas.

The prices concerned, nevertheless, dominated the strategy out for manufacturing, Perrino informed Spectrum. “The ceramic and chips all needed to be good,” he stated, and there was zero “likelihood of this taking place.”

He concluded a printed-circuit board was a should, however methods to mount the chips to it? Fairchild’s plastic DIPs had been too massive and expensive for the job. He had, although, learn a paper by Common Electrical engineers on beam tape packaging (BTP), a forerunner of what’s now referred to as tape automated bonding (TAB). After investigating BTP, he informed Fairchild and Polaroid administration, “If we don’t do it this fashion, it’s not price doing.” Each agreed.

BTP employed reels of movie with copper traces laminated on it round preexisting holes. Chips with bumps of solder on their pads had been centered underneath the holes and bonded to the overhanging copper lead frames. Particular person die/movie modules had been then encapsulated, examined, clipped off the reel, and soldered to the circuit board.

Perrino laid out the double-sided printed-circuit board at house on paper unfold throughout his pool desk. He then visited a number of corporations that made polyimide interconnect movie, contracted with 3M as a provider, and persuaded West-Bond Inc. of Anaheim, Calif., to construct gear for attaching the cube to the reel of laminated movie. The ultimate circuit board held three IC cube and two flip-chip, thick-film, laser-trimmed resistors.

Nonetheless, yields weren’t following the anticipated studying curve on two of the three ICs, the ability transistors due to excessive doping ranges and the timing chip as a result of, stated Perrino, of design errors. For instance, Jim Feit, one other engineer on the mission, recollects a parasitic machine affecting the flip-flops, which was mounted with the addition of a delay.

Nonetheless, although the elements weren’t low-cost, costing Fairchild roughly $20 or $30 every, they had been manufacturable.


The SX-70 was launched in April 1972, along side the corporate’s annual stockholders’ assembly. A 12 months earlier, Land had teased the stockholders by pulling a prototype SX-70 out of his pocket and waving it within the air. That was a working mannequin, containing one in every of TI’s first profitable ceramic circuit boards. However for this assembly, Polaroid wanted 20 cameras, and John Burgarella, now retired from the corporate, needed to make a number of journeys to Texas to hand-carry sufficient working boards again to Cambridge. A couple of month earlier, Land had introduced Fairchild engineers Perrino, Murphy, and Will Steffe to his Cambridge workplace and demonstrated the digital camera to them. “It was clearly a technological breakthrough,” recalled Perrino, which motivated them “to return and make the factor work.”

u200bMan holds camera at chest level and waves photo above head with other hand

Edwin Land confirmed the primary working SX-70 digital camera at a stockholders’ assembly in 1971. It was solely a prototype, and contained one of many first working ceramic circuit boards produced by Texas Devices. A TI engineer had put in it the evening earlier than the assembly, working with a digital camera that was shrouded to forestall him from studying something extra about it than he already knew.

The introduction went off with no hitch. A couple of dozen scenes, from a poker sport to a baby’s birthday celebration, had been enacted in a big warehouse, and well-known photographers had been capturing them with the brand new cameras whereas Polaroid stockholders circulated and examined the photographs. Polaroid engineers had been additionally circulating, with additional cameras of their pockets in case something went incorrect.

Resting on their laurels

So Fairchild received a contract to fabricate the publicity management modules together with the motor circuits and the flash management circuits. The commerce press touted their victory. In keeping with a January 1973 Digital Information report, as an illustration, this contract, “believed to be the most important ever issued by a digital camera producer to an electronics provider,” was price $19 million, and was “thought-about by some semiconductor executives as an omen of appreciable future enterprise.”

Fairchild disbanded most of its design workforce, happy with their success. However the manufacturing engineers pressed on, since the price of the product needed to be diminished by three-quarters or extra to satisfy Polaroid’s value goal, and contract negotiations had been to be reopened for 1974. Nonetheless, stated Perrino, two of the chips within the publicity management module had been nonetheless in bother.

C. Lester Hogan, who had just lately left Motorola Inc. to take over the Fairchild presidency, blames Fairchild’s then-outdated manufacturing services. He began a modernization, however he stated, “there wasn’t loads of additional money,” and it was not full till someday in 1974.

Perrino blames the IC designs as effectively. “The design guidelines utilized in these chips had been touch-and-go with the expertise,” he informed Spectrum. Polaroid’s Carcia agreed: ‘‘We had been pushing the elemental expertise.” Redesigning the chips was talked about, however administration didn’t mandate it.

A matter of pleasure

The TI design workforce was additionally disbanded in 1972. Some left the corporate, some moved on to different tasks. The failure, one design engineer informed Spectrum, was a black mark that harm careers.

On the highest stage of TI, nevertheless, the e-book was not being closed. TI chairman Haggerty reportedly referred to as his outdated good friend Land and stated, “We at TI don’t fail.” He assigned the mission about $540,000 from his personal funds, and informed his managers to do no matter it will take to succeed. The code title Challenge Alpha emphasised the significance of the contemporary begin, and Haggerty put government vp Bucy answerable for it.

The failure, one design engineer [said], was a black mark that harm careers.

As the unique TI workforce had been disbanded, Bucy deliberate to assemble one other one from the semiconductor division, and to make sure that this one would talk straight with Polaroid and still have manufacturing tasks.

Dean Toombs, engineering director of the semiconductor group, held a collection of conferences and developed a proposal for the redesign that was one other break with TI’s first strategy: it relied not on confirmed however on state-of-the-art IC expertise and packaging. A circuit board just one/64 inch thick was to carry as much as 4 digital (not analog) ICs and eight discrete parts at most. The chips could be floor mounted to the board in a miniDIP package deal, a technique of quantity meeting then new and dangerous however low-cost. (It’s now referred to as SOT, which stands for Small Define Transistors.)

The plan was permitted by Bucy, and Henri Jarrat (then Eljarrat) chosen to move the hassle. At first Jarrat objected to the project, however gave means when informed it was TI’s prime precedence. Given carte blanche to assemble a workforce from anyplace within the group, he stored the group manageably small—solely 18 individuals. They shortly partitioned the circuitry into three ICs and offered a six-month schedule for the redesign to Fred Bucy and Polaroid president William McCune.

Expert specmanship

Then Jarrat had his first assembly with Polaroid engineers. He informed them he might solely combine the publicity management perform into three parts in the event that they waived a few of their specs. He started taking place his checklist and to every request the Polaroid engineers stated no. So Jarrat stood up, threw his papers down, and stated, he recalled, “Now I do know why this mission goes nowhere. This may by no means work, and I don’t wish to have my title hooked up to a failure.” He charged out of the room. Toombs backed Jarrat’s menace. “We needed to get the shopper underneath management,” he informed Spectrum.

The flexibility to barter was partially additionally as a result of availability of working cameras to check and the development of a prototype on which to check breadboards of the chips—luxuries denied the primary TI workforce.

After a quick adjournment, the assembly was reconvened and from then on Polaroid negotiated specs. For instance, the 20-second trip, for taking an image in a dimly lit room, had made the sign from the photodiode impossibly low for the primary design groups and this time round was lower to 10 seconds. “The large motive for our success was Jarrat’s success at convincing them to ease the specs,” stated Clark Williams, a member of the second workforce.

The flexibility to barter was partially additionally as a result of availability of working cameras to check and the development of a prototype on which to check breadboards of the chips—luxuries denied the primary TI workforce. And when the primary group did elevate questions out of concern for manufacturability, recalled Buss, the one TI engineer to work on each the design and the redesign efforts, they had been informed, “Effectively, your competitors can do that.” And, in truth, Fairchild engineers don’t recall that the specs had been problematical.

TI started producing the Challenge Alpha boards in amount in mid-1973.

table listing part types and quantities

With the redesign, TI quoted Polaroid a value of about $4.10 a unit—effectively beneath the $5.75 goal. Mentioned former Fairchild president Hogan: “On the time, it price us $10. We actually believed we might get it to $6, however when TI bombed the value down to 2 thirds of the goal value, we simply needed to drop out.” As for a redesign, stated Hogan, “we didn’t have the cash to speculate that means—we needed to put money into the generic fixing of the manufacturing unit.”

TI created a particular digital camera division with Polaroid as its solely buyer. The corporate made about 850 000 items in 1974 and continued to supply the design till the SX-70 and the SX-70 Mannequin 2 had been discontinued in 1977. It additionally spun off a number of improvements, together with packaging for TI’s watch shows. And the engineers on the Challenge Alpha workforce had been rewarded with then substantial raises of $100 to $500 a month.

West-Bond and 3M, corporations Fairchild had recruited to fabricate packaging gear and movie tape, continued to profitably produce them for different corporations.

Fairchild used the BTP packaging expertise it developed for the SX-70 on its high-volume plastic DIP merchandise at a number of manufacturing services. It additionally took its digital camera management expertise abroad on a tour of Japanese digital camera producers, however after a number of unsuccessful months gave up and closed down the manufacturing line for the publicity management module. It continued to fabricate flash management modules for Polaroid for one more 12 months, nevertheless. Inside six months to a 12 months of dropping the publicity management contract, no less than half the individuals who had labored on the mission moved to different corporations, Feit recalled.

Comfortable ending

Might the design have gone extra easily? Definitely higher communications between Polaroid and the 2 semiconductor corporations and amongst totally different divisions inside TI and Fairchild would have eradicated a number of the tough spots.

From Polaroid’s standpoint, the knowledge it handed out was as full because it could possibly be. In any case, a number of elements of the digital camera system had been being developed concurrently, in order that the system specs couldn’t in the meantime be finalized. Additionally, stated one Polaroid engineer, unfamiliarity with pictures impaired the IC designers’ comprehension of the information they got.

Within the eyes of the TI and Fairchild engineers, helpful data was withheld, and Polaroid engineers do admit a preoccupation with secrecy.

Nonetheless, within the eyes of the TI and Fairchild engineers, helpful data was withheld, and Polaroid engineers do admit a preoccupation with secrecy because of concern over competitors from Kodak. Maybe being informed that sure design points had but to be resolved or an in depth rationalization of how an SLR features would have elicited extra inventive engineering from the IC designers.

Be that as it could, the SX-70 was an excellent success. Polaroid bought some three million items of the leather-covered Mannequin 1 with its chrome-plated trim and the plastic-bodied Mannequin 2. (Mannequin 3, launched in 1975, was not an SLR.) So whereas the design issues each TI and Fairchild endured triggered tense moments in any respect three corporations, their answer opened up an enormous new client market in electronics.

To probe additional

For particulars on the SX-70 circuitry, see “Behind the lens of the SX-70,” by Gerald Lapidus, IEEE Spectrum (December 1973, pp. 76-83).

Each Time and Life magazines featured the SX-70 digital camera on their covers in 1972, and mentioned it in “Polaroid’s Massive Gamble on Small Cameras” (Time, June 26, 1972, pp. 80-82) and “If you’ll be able to state an issue, it may be solved” (Life, October 27, 1972, p. 48). To grasp how the event of the SX-70 match into Polaroid’s Jong historical past, learn The Immediate Picture: Edwin Land and the Polaroid Expertise by Mark Olshaker (Stein & Day, New York, 1978).

Frank Perrino’s model of tape automated bonding is described in U.S. Patent #3,868,724, “Multi-layer connecting buildings for packaging semiconductor units mounted on a versatile service,” dated Feb. 25, 1975.

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