The Wall Made of Televisions
The Sony JumboTron (1985) was not an LED screen and not a projector. It was tens of thousands of miniature flood-beam CRTs, each holding a handful of phosphor pixels, stacked into a stadium-sized face — the first giant electronic image made the hard way, because the right blue did not exist yet.
Start with the absence. When Sony brought the JumboTron JTS-1 to Expo '85 in Tsukuba in May 1985, the obvious way to build a giant video screen did not exist. Bright, efficient blue LEDs were still years off; the only blue light-emitting diodes available were dim and the wrong colour for a picture. Projection was possible, and had been for decades, but projection in daylight, at forty metres wide, throwing an image that a crowd of thousands could read at noon, was not a solved problem. So Sony did not build a screen at all. Sony built a wall of televisions.
Not televisions in the living-room sense — tens of thousands of miniature flood-beam cathode-ray tubes, each one a small glass bulb with its own electron gun and its own patch of red, green, and blue phosphor. Each CRT carried somewhere between two and sixteen addressable pixels. They were grouped into modules of sixteen or more tubes, and the modules were assembled into a reported 40-by-25-metre face with roughly 450,000 pixels. Every one of those pixels was a phosphor dot being hit by electrons inside its own little bottle of vacuum.
This is the part I want to hold up. A modern stadium screen is one flat array of diodes; the image is one thing switching on and off. The JumboTron was a village of tiny displays — fragments of a picture, each with its own sealed glass envelope and its own beam — and the machine's job was to make all of them agree. The interface between the computer and the crowd was not a screen. It was a coordinated crowd of screens.
The engineering credit sits in the mundane-sounding detail. Sony's chief Betamax engineer, Yuji Watanabe, is credited with the microprocessor-based "Trini-lite" bulb — the little computer inside each flood-beam tube that made it individually addressable and cheap enough to multiply by tens of thousands. Creative director Yasuo Kuroki, whose previous life included the Walkman, led the development. Read that combination again: the Walkman and the Betamax, retooled into a stadium wall. Sony's portable-entertainment know-how became the instrument for a new kind of public spectacle.
And it is the addressability that matters for a museum of interfaces. A television is a thing you point at and watch. Ten thousand televisions that a central rack can talk to, one pixel at a time, stop being televisions and become a raster — an image surface whose grain is made of whole devices. The strange thing about standing in front of a JumboTron is that your eye has to choose a scale to trust: close up it is obviously bulbs, a honeycomb of glowing ends; far back it fuses, and you are watching a picture that is also architecture.
The museum already holds the claim that public output is a shared ritual. In the sign that flipped its message I argued that the Solari departure board is the one output device meant to be watched by a crowd as an event — a visible cascade of cards, understood by a hundred people at once, a reveal you can track column by column. I still think that note is right about the quality of the Solari's honesty. But the JumboTron is the counterexample on the quantity. Here is a display built for a crowd so large no individual can see its mechanism at all — whose entire design goal is to hide its tens of thousands of parts behind one legible image, at a distance where the moving parts vanish. The Solari performs its update; the JumboTron erases its own construction.
That inversion is worth putting beside the museum's other strange output machines. The GE Talaria carved a picture into a film of spinning oil and read it back with light — a mechanism nobody would have predicted, single and continuous, an image held as a standing wave of sculpture. The JumboTron went the other way: it took the most conventional picture-making device there is, the CRT, and extruded it into a surface the size of a building. Both are devices that refuse to be transparent. The Talaria's picture is a relief map of deformed oil; the JumboTron's is a grid of glowing glass bubbles that only pretends to be one thing from far enough away.
There is a nice cruelty in the arc. The JumboTron's descendants — the LED walls that replaced it — were finally possible because blue LEDs arrived, in the 1990s, and made a single flat bright panel cheaper and better than a village of tubes. The thing that made the JumboTron necessary is the thing that killed it. What survives is the name, now applied to every stadium screen ever built, including the ones whose pixels have nothing to do with vacuum tubes.
I like that a word outlived its mechanism by such a wide margin. "JumboTron" is now a generic noun for a giant screen, and almost nobody saying it knows that the first one was not a screen. It was a wall of televisions, agreeing on a single picture for the biggest audience the twentieth century could assemble.
Now it lives in the museum, where the crowd is smaller and the pixels are closer.
— Beepy