Historical Document · 1967
Electronics, 29 May 1967: Ise's Low-Voltage Numerical Display Tube
The first public report of Ise Electronics' vacuum-fluorescent numerical tube, from Electronics magazine of 29 May 1967, pp. 212-213.
Historical Document · 1967
The first public report of Ise Electronics' vacuum-fluorescent numerical tube, from Electronics magazine of 29 May 1967, pp. 212-213.
Electronics Abroad term variations due to respiration are averaged out when reading the chart. The sensor on the thumb sends an impluse to the preamplifier, fil- ter, rectifier, and power amplifier, which make up the servosystem control for the motor. The motor activates a pump which sends im- pulses back to the bulb around the finger as well as to the manometer. The first units contain silicon transistors. Svensson says second- generation devices will have hy- brid integrated circuits. This will improve reliability rather than re- duce size, since the graph holder and clock cannot be made much smaller and still produce a read- able chart. Updating an old trade Armaments have been an important export item for Sweden since the Thirty Years’ War more than 300 years ago. The business is now taking a new direction: the ex- porting of complete and highly sophisticated defense systems. The Paris Air Show, May 26 to June 4, marked the first marketing effort abroad by Swedegroup, a consortium quietly formed about a year ago by six Swedish companies in the defense electronics, aviation, and munitions industries. Establishment of this venture doesn’t mean the companies will drop their individual operations, but Swedegroup will handle the promotion of large joint projects. “The offer by major Swedish com- panies of a complete defense sys- tem will be more attractive than bids from each firm for a piece of the business,” says Frank Cervell, managing director of Swedegroup. The most obvious potential cus- tomers are neighboring Scandi- navian nations and neutral coun- tries elsewhere. A big selling point will be the claim that the inde- pendence and stability of nations will be served if they build up their defense systems with equipment supplied by neutrals like Sweden rather than by one of the major powers. “I’m thinking of nations in Africa and Asia, for example,” says Per Odelberg, managing director 212 of AB Bofors, one of the members of the consortium. “If they buy de- fense materials from Sweden, they get them with no strings attached.” Swedish policy prohibits the ex- port of arms to nations at war or those at swords’ point. This restric- tion would rule out many potential customers. At Paris, Swedegrcup showed a high-speed radar display unit that uses integrated circuits. The maker, Standard Telefon & Radio AB, says the system displays alphanumerics, symbols and graphics, and will be available in digital and analog versions. Also shown at Paris was an auto- matic technique for testing the avionics in the new Viggen air- craft, radar for the latest version of the supersonic Draken fighter, and a miniaturized airborne digital computer. Japan What’s up front counts Many variations of the cathode-ray tube have been developed through the years but the latest change may well be the most radical. Now there’s an inside-out crt designed as a digital readout tube for elec- ——__ tronic desk calculat tional tubes have the cathoavets the rear, but the new crt eae’ in Digitron—has the cathode y t the Invented by Japan’s Tadashi . kamura, president of the Ise E] 2 tronics Corp., the Digitron ; Se. joint Ise-Hayakawa Electric ©, sa velopment effort. Hayakawa i de- corporating the crt into a lin . calculators scheduled for a “ot debut, fal Not only is the new tube but its cost is low and small ) it requ; little power, says Nakamurat who invented the one-gun Colometron picture tube [Electronic 1965, p. 81]. * May 31, Vanishing cathode. Digitron has phosphor-coated number segments toward the rear. The 30-micron- wide, forward-mounted filamentary cathode is kept at a low-enough temperature so that its faint glow isn’t discernible, says Ise A space- charge grid, consisting of 15-micron wire woven into a 100-mesh-per- inch screen, is located directly behind the cathode. Segments of numerals are outlined by a photo- etched screen electrode that serves as a mask to define the individual segments. This simplifies produc- tion by eliminating the need for precisely shaping the segments. The phosphor segments are at- tached to a ceramic support, which has lead wires extending through FILAMENT REEN | — St ECTROOE PHOSPHOR > SEGMENT EXTE RNAL LEADS Mic — CERUPLATE gital readout tube its. Cathode lope is | ts glow. 29, 1967 Planar display. New di draws as little as 15 vo mounted up front in enve ible when number-segmen Electronics | May Electronics Abroad _ segments consist of a resis- er—which makes contact to tive Jay ment leads—and a zinc the ¢ phosphor layer . orrhe cathode location is not just f departing from a con- a matter cme. Electrons are vent) from the oxide-coated fila- enmity all directions. Those start- : ent ward the envelope are re- aie d toward the space-charge grid by the negative charge that collects on the envelope s inside surface. Ise says careful design of the tube eometry assures that an electron shower with constant density at all pints passes through the grid which is operated at +25 volts. The screen electrode has the same 95-volt potential, and electrons con- tinue on toward it. Lighting up. Phosphor numeral segments can be turned on at 25 volts, or as low as 15 volts. The electrons strike only those segments needed to make a selected numeral glow. The remaining segments are held at zero potential. Heater input is 0.8 volts at a cur- rent of 90 milliamperes. At an ac- celerating potential of 25 volts, the total cathode current is 7.7 milli- amperes. Regardless of the number of phosphor segments switched on, eathode current remains constant because of the shielding effect of the space-charge grid. Current within the tube changes, however, depending on the number of seg- ments that are turned on. For a typical numeral, the total phosphor Segment current is 0.7 milliam- Pere. The remainder of the current Bees to the space-charge grid and Screen electrodes, which are in- temally connected, peri he Digitron has a two-digit- Measi, density. The numerals » ssure 0.46 inch high by 0.35 Inch wide, in a cylindrical glass inches h; ch in diameter and 17 a ecimae The display includes Shines pboint and a prime mark. Breen 1 rightly, Since the bright UMmerical display is formed SMents that lie in the same > Numbers do not “dance” as dischar. In multiple-cathode gas- brightnos tubes. Ise says display bers “Ss is at least 80 foot-lam- *“"8itron can provide a dis- Y se Plan, they Ly . “etronics | May 29, 1967 play at 15 volts and can be switched directly by integrated circuits. The device can operate from 15- to 25- volt, d-c power supplies. The company says operational life isn’t known yet but reports tubes have been running upwards of several thousand hours. Calculated entry The latest entry in Japan’s calcu- lator sweepstakes is the Sony Corp., which will be off and run- ning on June 1 with an electronic desk mode] that uses hybrid inte- grated circuits and has two mem- ories. Called the Sobax, for solid state abacus, the unit will be priced at $722. Plans call for a 500-unit monthly production quota initially, with sales limited to Japan. A first. Although its price is slightly higher than the lowest- priced Japanese calculators now available, Sony’s entry seems to be competitive. It is a 14-digit calcula- tor where most of the others have 12 digits and lack a memory fea- ture. The new unit operates from low-voltage d-c power supplies and is the first made in Japan that blanks out all zeros before the first significant digit. Sobax uses a single ultrasonic delay line—invented by the Uni- versity of Osaka’s -Zenichi Kita- mura—tfor five registers; and is believed to be the first to incorpo- rate this feature. Three of the reg-: isters are used for arithmetic and the other two operate as memories. The delay line performs the functions of five registers on a time-division basis. In the multi- plexing scheme, the registers are numbered one through five. The first bit for each register is inserted into the delay line in sequence; then the second bit of each, and so on. Coiled in a metal box and housed at the base of the calcula- tor, the 3-meter-long delay line has a capacity of 360 bits and a delay time of 1.5 milliseconds: Time sharing. The clock fre- quency is about 40 kilohertz and the time interval of each clock pulse is divided into six phases— one for each of the five registers and one more for synchronizing the delay line. Although they are now using hy- brid ic’s, Sony engineers indicate that they may eventually switch to monolithic circuits. Use of hy- brid circuits fits in with Sony policy, since one reason for mar- keting this calculator is to make use of the production at Sony’s semiconductor plant. Company officials say that purchase of out- side units even at low cost would negate an important reason for building the device. There are 500 1c’s mounted on the calculator’s five printed-circuit boards. These circuits have a total of about 8,000 individual compo- nents, including 200 transistors and 1,700 diodes. The hybrid circuits are built on alumina substrates and are dip-coated for moisture pro- tection. Transistors are the only com- ponents within the hybrid circuits that are prepackaged in epoxy. The transistors are the same type used in most of Sony’s tape recorders, radios, and television sets. Diodes and capacitors are attached to the substrate without prior encapsula- tion. There’s a difference. Logic cir- cuits consist mainly of diode gates and transistor flip-flops, with a sprinkling of inverters. Among dif- ferences. between logic circuits developed by Sony and those that are used by most other firms are the connéctions between gates and flip-flops, and between clock input and flip-flops. Sony uses capacitor coupling between gates and flip- flops, and d-c coupling of clock to flip-flops. Other manufacturers use d-c coupling between gates and flip-flops, and capacitor coupling of clock to flip-flops. Great Britain Against the tide Engineers developing methods of interconnecting integrated circuits for International Computers & 213