DE2209382A1 - Display device with at least one electrically controllable display element - Google Patents

Description

Dipl.-ί'Κ). Heinz Lesser, f'utentonwait D — ii Mün-Joii 81, Coäirnastro & e 81feathers: (C-311WJ &

Kabushiki Kaisha Suwa Seikosha L 96.13 / Fl / ho. Tokyo (Japan)

Display device rnib at least one electronically controllable Display element

The invention relates to a display device, in particular for a timepiece, having at least one electrically controllable display element, dan Rait means of electrical potentials above a certain Grenzberelches switched on and with such below a certain F, ch> / e I Lv / ertbereiches is abnchaitbar ,

Fs are a series of display devices with passive Display elements known that at. Applying an electrical signal make visually perceptible changes, see above the scattering, absorption, conduction or polarization of light.

The passive display elements work in general with a very low Ennrgic. You are therefore in front of everyone Things for fully electronic clocks, especially electronic « Wristwatches of small design, excellent yaeignat.

Other rs ii lts need cUfi «e passive display?» learn te sine relatively high supply voltage, v / as leads to in the drive power circuits .schv / acha lacquer currents occur, which can affect the display radio Lon, another The characteristics of this display line consist of: that an optLsch perceptible display only when exceeded; a certain threshold voltage takes place. These conditions v / will be explained later using the examples shown in the drawing.

209838/0757

Dipl.-Ing. Heinz Lesser, Patcntonwolt D-8 Mönchen 81, Cosimastro & e 81 Telephone: (0311) 983820

Mib of the present invention is intended to be a display device of the type mentioned are made available, one or more display elements of which can be switched on and off without the leakage currents occurring being able to affect the switching status of the display element.

According to the invention, this is achieved by at least one switching device connected to the display unit, in one switch position the display element at a potential difference above the limit range for the Is switched on and in the other switch position of which the display element is exposed to a potential difference, whose value is below the threshold value range for the shutdown state.

While a simple on-off switch can have such a low leakage resistance when it is switched off, According to the invention, the voltage drop on the display element can be sufficient to maintain the display unintentionally a potential that is sufficient to safely switch on the display element, a second when it is switched off Opposed potential which is dimensioned so that the remaining on the display element Lm switched off Potential difference below the threshold value for the Switching off the display element lies. This second The potential lies directly at the leak resistance, so that its effect on the potential difference on the display element independent of the (! rosse dus leakage resistance.

In terms of circuit technology, the procedure can in particular be such that at the output of the switching device the one electrode connection of the display element is connected, the other electrode connection of which is connected to a first potential tial, the reference potential of which is connected to the input connected in one switching position of the switching device the switching device is switched on, while at the other input there is a second potential, which is opposite to

209838/0757.

Dipl.-Ing. Hein? lesser. Poterilonwoli D-'ϊ t - / - r-di «n 81, Ccsiti ^ lroi / -Sl · Telephone: (0311) 983320

the same reference potential forms a potential difference with the first potential, the value of which is below the threshold value range.

If one imagines a normal mechanical changeover switch as a universal switching device, then one electrode is of the display element is connected to the center contact of the switch. The one in the switched-off state with the center contact connected contact is at the Besugspotential, while the connected contact is connected to the central contact Contact is at the second potential. Such a Shift-I

contact can be realized in many ways with a wide variety of switching elements. Especially preferred! Execution two transistors are used, in particular as field effect transistors with an isolated control electrode are trained. One csr can use both transistors be of the P-type and the other be of the N-type? ice transistors are then in series between fiam second. Fctenfcial and the reference potential "

The invention is based on the wiäargegefoeneu in tariff Examples explained in more detail, It show

Fig. 1 is the diagram of an example of a typical relationship between the applied! Sp and the achieved display clearly indicated sices passive on 3 separate lines of the kind shown here Id Fmgs;

FIG. 2 shows an example of a conventional control gear . FIG. 3 shows a circuit diagram to illustrate the invention

Fig. 4 is another basic Lieb ™ -f circuit diagram of a switching device, ·

Fig. 5 is a concrete Ausführungshelspiel UesGli a device according to the ErfiriGungi

209838/0757

Dipl.-lncj. Heinz Lesser, Potonltinwoll D-8 Miimlic-n 81, Cosimastrafir 81 ■ Telephone: (0811) 95 33

6 and 7 circuit arrangements for operating a

wristwatch equipped according to the invention.

The diagram according to FIG. 1 shows the basic dependency between the applied voltage and the brightness of the display in the case of a passive display element. Included is plotted starting from the zero point Ö along the abscissa χ, while the Masäbab for the brightness or Clarity of the display is located on the y ordinate. The desired maximum value of the brightness is with the Criterion "1" specified. According to the dependency curve 1, the brightness is low between the zero point of the diagram Ö and the voltage V., while between the voltages V. and V_ there is a change in brightness or clarity of the display between a low value - non-excited state of the display element - to a higher word - excited state - takes place. Similarly, curve 1 'gives the inverse dependence between the Voltage and brightness according to curve 1 again. As can be seen from the illustration, V is the so-called Threshold voltage.

According to FIG. 2, the passive display element 4 located between two connections 2 and 3 of an energy source is actuated with the aid of an on-off switching element 5 connected in series. The resistor 6 illustrates the leakage resistance that occurs in the open switching state of the switching element 5. This leakage resistance 6 can be so small that the result of the voltage division in the open state of the switching element 5 applied even to the display element 4 ^r Sbannung exceeds the threshold V, so that the display element even in the open and tying the SchaltelementGS 5 further as indicating in the display state. The parallel connection of a resistor to the passive display element 4 to compensate for this undesirable phenomenon is disadvantageous, since the value of this resistor

209838 / U7 57

Dif.! .- lnq. Heim Le. '. Ift, Patentrmwalt D ~ 8 MmuKn Bi, Cosimaitralje 8! · Tt'lt-fon: (C ^ l 1) 933320

must be correspondingly small compared to the leakage resistance 6, whereby a relatively high leakage current occurs.

The invention is represented symbolically in FIG. Between the terminals 7 and 8, a first electrical energy source is connected, while between the Connections 7 and 9 is a second electrical energy source, the voltage of which is greater than / equal to the voltage of the mentioned first energy source is. Between the two connections 7 and 8 are the contact parts to be controlled a switching device 11 reproduced as a mechanical switch is switched on. Between the common The switching element 12 and the connection 9 is the passive display element 10. 13 and 14 represent leakage resistances which are assigned to the corresponding switching paths of the switching device.

As can be seen in FIG. 4, the switching device can also through separate L in-off switches 15 and 16 be realized, the opposed ai.be.iten, their one alao is closed while dar. others are im <j! Opened state be 0 Indes I; and vice versa. Such switches

I can be realized through a multitude of bükarmtan switching elements.

Is. the common switching element 12 of the UiUiSchalfcGlnrichtung

II is now connected to connection 7, then: the passive display element between cue connections 7 and 9 is switched on, at the display element Io there is accordingly dl ^, voltage between the · connections / and ^! >üineschalU; ton energy source Lüt anUorersEitii dan SJch-ilLgLlod L2 connected to the connection 8, r> o see iIaü passive display element 10 between the connections B and 9; the difference between the voltages of the energy sources switched on between terminals 7 and B on the one hand and between terminals 7 and 9 on the other hand is now up to the counterpart. Sor-jt there door now, da.-jη represents the tension between the

209838/0757

Dipl.-lnq. Heinz lessci. Potonlonwalt D-8 Mundu-n 81, Cosimostmfcc 81 Telephone: (0811) 933820

Terminals 7 and 9 switched-on energy source is high enough to transfer the passive display element 10 into the excited, ie switched-on, state, and one continues to select the voltage of the other energy source switched on between terminals 7 and 8 lower than the voltage of the aforementioned Energy source, namely in such a way that the difference between the voltages of the two energy sources is smaller than the threshold voltage of the display element, an exact switching on and off of the display element can be achieved. The voltage applied in the off state of the display element voltage can be limited to a precise value below the threshold voltage, because the power source voltage between the terminals 7 and 8 in the off state of the switch device 11 is always in the full amount of the power source voltage between the terminals 7 and 9 counteracts, regardless of the size of the leakage resistance

Due to the free choice of voltages and energy sources, or the voltage of the energy source between the terminals 7 and 8, it is possible for the switching direction Halb-Ie L tore linen te mLt non-linear leakage resistance characteristics tik to use.

In Figure Γ> Lst ο Ln a specific embodiment according to the invention. The switching device is formed from two FeLrioifekt-TransLntoren of the enrichment type. Finer dor transistors U; t a P-channel transistor 23 and the aruloru an M-channel TrannLstor 24. A display element 22 which works with a nematic liquid crystal is connected to the interconnected drain electrodes of the transistors connected in series. A reference potential, for example of the value 0 volts, is present at connection 17. To the terminal 19, a potential is turned on having a differential potential relative to the reference potential at terminal 17 which is sufficient

is austiiiuiic ι

209838/0757

Dipl.-Ing. Helm U-sspr, PaJnriliinvroH D-8 WGndujn 81, O .-. U.wU'ifr ΓΠ · Telephone: (0311) 983Β / 0

around the indicator element 22 in the energized, i.e., switched on State to be transferred «A potential is switched on at connection 18 which is equal to / less than is the potential at terminal 19, in such a way that the difference between the potential at terminal 19 and which at connection 18 is smaller than the threshold value below which the display element 22 is in the switched-off state is located.

If a potential is now given on the common control electrode connection 20 of the two transistors, which corresponds approximately to that of connection 17 (almost 0), the potential of control electrode GN of transistor 24 also becomes almost 0, whereupon the resistance between the source Elitrode SN and the drain electrode DH assumes a considerable value. On the other hand, the control electrode GP of the transistor 23 is given a potential with respect to its other electrodes, which causes the resistance between the source electrode SP and the In ain electrode DP to drop considerably. As a result, the potential at the connection point 21 of the drain electrodes of the transistors 23 and 24 is approximately equal to that at the connection 10. On the / display element

22 is accordingly a potential which is approximately the difference between the potentials at the connections 18 and 19 with respect to the connection 17 corresponds. However, this potential is selected in such a way that it is below the threshold potential of the display element is so that the display element 20 is switched off with certainty. (Flows in in this case a current from the connection 19 to the connection 21, which the current from the electrode DN to the connection 17 exceeds, the drain electrode DP of the transistor

23 has a positive potential with respect to the connection 18.

But there between the drain electrode DP and the carrier material SuP is a diode, the potential in question is always approximately equal to the potential of the Connection 18.)

2098 3 8/0 7b7

Dipl.-lnq. I lcinj lessor, PoU'ntonwall D-8 Mfmdien 81, CoMmosltofio 81 · Telephone: (0811) 983820

If now, according to the other switching state to be assumed, on the connection 20 of the control electrodes If a positive potential is approximately in the order of magnitude of the potential at connection 18, then the potential becomes of the control electrode GP of the transistor 23 with regard to the potential at the connection 18 almost 0, whereupon the Resistance between the source electrode SP and the drain electrode DP increases to extremely high values. on the other hand receives the control electrode GN of the transistor 24 with regard to the other electrode potentials Potential that leads to the resistance between the source electrode SN and the drain electrode DN this Transistor drops significantly. This increases the potential at connection 21 between transistors 23 and almost equal to the reference potential at the connection 17, so that the display element 22 receives a potential that is approximately the between the terminals 17 and 19 corresponds. According to the requirements, this potential is large enough to to transfer the display element to the switched-on state with certainty.

The concrete example described above of the use of a transistor pair to form the switching device serves to explain the invention. It is readily understood that the function of the invention used switching device can be simulated by many components, be it in the form of two individual elements or in the form of a combined switching element. Rather, it is important that the switching element the Fills the function that has been described in connection with FIGS.

The circuit diagrams according to FIGS. 6 and 7 show the use of the switching device according to the invention in the Connection with the circuit arrangement for a wristwatch. A pair of complementary devices is used as the switching device 55 Field effect transistors with an isolated control electrode.

209838/0757

Dipl.-Ing. Heinz Lessor, Polontonwalt D — 8 Munich 81, Cosimastrafje 81 · Telephone: (0811) 9Ö332Ü

The display elements work with liquid crystals nematic :: phase. The display is in Arabic numerals for Hours and minutes, each composed of seven segments. The seconds are displayed with the help of six circular areas that flicker every ten seconds can be controlled.

The block diagram of this circuit device is explained step-by-step in the following:

The time normal signal of an oscillator 25 is with the help a frequency divider 26 into signals of one second duration divided. This one-second signal is activated with Help einos L / 1.0-Z uh le rs 27 divided into a ten-second signal. Di.o:; he; '/e- one- second signal is then only HLLc «eiiuii · I / G counter 28 Ln a one-M-slot signal, übarführung, day the next stage is fed.

The step outputs of the 1/6 number 28 are connected with a conversion: YJ, whereby the output sign a Lo eiit- :: pL-uc'hf: iul every sec tor of the second customer ounce is obtained, this Au £ Hji. mqü5; LgnaLe are logically in \ 6 with an i; in-fü; kundan- '.'. Jlijnui, (.Lu; bi: i ¹ JfI atK / eiifjmnitm wird, nail tipi i /. Iarir, and dam btouüii; Loiruitit 5i) ziujii EvUir t. , Judat 'sector of the Sekun'.Uuiatü; 6ii.cjti is with eLiier. Trtiibsarci Le; mmiten-Gruppe 37 Viirbi'Udvüi, Lm result fLacknrt jo.ler; Eioktor dar Siik unfipceciiünd tlem jev / ε »LIi; an '/. uiiiiLgendun With ULLiB eLneii L / LO-i'.ähLürr » V) the Elri-MLnuten signal is converted into eLn Zelm-Minute- ^ LgnaL. This counter is connected to an ELn-Mnuten-ZLfferneLektrüde 24 via a segment converter 1 and a driver circuit 38. The driver circuit has seven driver elements 55, each of which is connected to a segment of the numeric display for the corresponding SteLla. With the help of a 1/6 counter 30, the Zohn minute signal is converted into a ELn hour signal.

209838/0757

Dipl.-Ing. Hfiiiw Lesser, Putentonwolt D-8 Murulion 81, Cosimcistiofje 81 ■ Telephone: (0311) 983020

- 10 -

The step outputs of this counter are with the ten-minute digit electrodes 43 connected via a segment converter 34 and a driver circuit 39.

Furthermore, the one-hour signal becomes a 1/12 counter 31 supplied; its step outputs are connected to the segment electrodes 41 and 42 of the corresponding numeric display connected via a segment converter 35 and a driver circuit 40. A switch 52 is used to reset the Frequency divider and counter stages to their initial switching state. Further switches 49, 50 and 51 allow the Corresponding numeric display of the ten-minute-ten-minute and kin hour display to set the desired value Each press of this switch leads to a logical one Addition mLt dun signals of the meter outputs of the previous ones Level independent for each »job advertisement and is assigned to the input tk> r according to the following counter as UhrunsignnL trains leads. This allows the payment status per Operation v / grounded by one switching step.

The potentials for controlling the segment electrodes are illustrated with a corresponding number of switching devices : r ye ij f.ib; \ η, which roughly equates to the value of V. or V in terms of oljcrt'irifjtimmung. the respective time to be displayed. DLe common electrodes 46 and 47, the segment electrodes 4L, 42, 4J and 44 as well as the seconds-AnzuLgö-ELelectrodt '. 45 are opposite, are connected to the potential V _L arujt;:; Datier gives £; I the PotfintiaLdiEferenz -between each segment electrode and the corresponding single electrode to:

V = ν - V
^V C ^V H ^V L

^or v ¹ = V - V

^V C ^V E ^V L.

For example, if you take display elements with liquid crystals ^ In the nematic phase, it is necessary that for the

209838/0757

Dip! .-! Ncj. lirm? Ir-OiPr ₁ P ₁ IIfTLMiWOU D - 8 iA.üd'twi 81, GüiW.Ua'f. » b \ ■ I ίοη: (Ü'311) ^! ! il;?>'lQ

- 11 -

In the event that the threshold voltage is V and the voltage V ₍ "is sufficient for the display, the potentials meet the following relationships:

^V C ^V 0N

V ^ V
C TH

Dadser

VV
^V H ^V E

is, it is possible according to the invention to supply the display elements with a voltage which is higher than that Clamping ring that is fed to the control circuits.

This higher voltage in turn leads to the simpler Execution of the control circuit a clear display reached wij.d. In addition, the total energy requirement degraded.

FIG. 7 shows an example of a voltage amplifier circuit for obtaining the potentials V ", V" and V _T from a single battery, with the aid of which the above conditions can be met. For this purpose, an annular GO grain is used, which enables a high degree of reinforcement and a particularly small construction.

The DC voltage of the battery 61 is converted into a pulsating voltage for the primary coil 63 with the aid of a transistor 62, a detector coil 64 and a base resistor 65. The required potentials V 1, V and V are taken from a secondary coil 66 with a center tap as alternating voltage and passed through rectifiers 67 and smoothing capacitors 68.

2U983U / Ü7S7

Claims (4)

Dipl.-Ing. Heim lcs; ci, Pulcnlünwall D-C Mündifin 81, Cosimosliafje Gl · Telephone: (0811) 983320 - 12 - PATENT CLAIMS 1./Display device, especially for a clock, with at least one electrically controllable display element, which with the help of electrical potentials above a certain limit ranges can be switched on and with those below a certain threshold range it can be switched off: is indicated by at least one on the display element (10; 22; 45, 47; 41 to 44, 46) connected switching device (11; 23, 24; 55), in whose one switching position the display element is due to a potential difference above the frequency range for the switched-on state and in the other Switch position the display element is exposed to a potential difference, the value of which is below of the threshold value range for the shutdown state. 2. Display device according to claim 1, characterized in that the one electrode connection of the display element (1O; 22; 45, 47; 41 to 44, 46) is connected to the output (12; 21) of the switching device (11; 23, 24) whose other electrode connection (9; 19) is connected to a first potential, the reference potential of which is connected to the input (7; 17) of the switching device that is switched on in one switching position of the switching device, while a second is connected to the other input (8; 18) Potential that forms a potential difference with the first potential with respect to the same reference potential, the value of which is below the threshold value range. 3. Display device according to claim 1 or 2, characterized 209838/0757 I ek ti η α 2 i i. -; ha; . ·. , (lafis die UmnuhaLteinrichtunf with: zv / oi Tt -hi .-. · izl ; ^- > ran (23,24) c / «bLl.cUit Lst, 4. An /, t: i: j'-j '.; Iiit i.tu.u n, -it.: H. · ... ■ r-.jjrujh "3, d a -i u r. C it η ekaa η ζ a L t; h α t ». t. that glüul · der a'ransiiu P-Tyρ ur.rl eLncif Ό! · '>"·'-''-'/ ρ int. λι ·. uiLv / uOLiiL i.chLu.,! ut: ..- ■ ■ h in :: i -inl "Ji-InPrUUlIf-- J odor 1, d α Major ο ι h / u i. · .: it ί><£ verifiable net that ■ ί ί . -a Trans ls; to ι on a Lu Fj · i. .u ·. ... L ";? ki: .'- Tr; ans Lu tOL an (2 J, 2« i) aiusyebiLdet .-Mj ι ■; 11 / eerse ι t e