Driving method for image forming device

[Detailed Description of the Invention]

[Industrial Application] The present invention relates to the drive method of the image forming device provided with the grid electrode for modulating the electron beam group emitted from many electronic discharge elements and the electronic discharge element of above-mentioned a large number.

[Description of the Prior Art] He is M Elinson (M, I.) as an element from which electronic discharge is conventionally obtained with an easy structure, for example. Eye The cold cathode element announced by Elinson etc. is known.

[radio engineering electron Fiji 4- A (Rad (o Eng, EIectrar+.)) the [ Ph2s and ] -- 1O volume, 1290~129B page, and 1965] -- as this kind of electronic discharge element The thing using the Sn0? (Sb) thin film developed by the above-mentioned Erinnan etc., it is based on Au thin film -- thing [Gee Dietmar" Swinsolide 74I carrying out -- JAA*' (G) Dittmer: "Th1nSolid Films", nine volumes, 317 pages (thing [to depend on ITO9 film 1972 years, a M Hartwell and See Gee phon a stud "eye EE E transformer" E Day- concentrated (M)) Hartwell and C, G Fonstad: IEEETrans, ED Conf, "519 page (1975)], : besides [ which is depended on a carbon thin film ] thing [Hisashi Araki "vacuum." @28 volume, the 1st item, and 223I (1983) --] Natuka report is given. Many electronic discharge elements with a thin film heat cathode, a promising MIX form discharge element, etc. have been reported besides the above. Rapid progress and interval of membrane formation art or photolithographic technique are becoming possible [ forming many elements on a substrate ], and these are a fluorescent character display tube and monotonous type CRT as a source of a multi-electron beam. The application to various image forming devices, such as electronic B and a Beam drawing device, is just going to be expected.

[Problem(s) to be Solved by the Invention] By the way, it is although arrangement formation of many elements is carried out, it wires electrically and between each element is generally used as a source of a multi-electron beam with the electrode of a thin film or a thick film on X board, when applying these elements to an image forming device, The phenomenon in which the voltage impressed for every element for the voltage drop which arises in wiring resistance will vary occurs. As a result, the problem that the current amount of the electron beam emitted from each discharge element showed variation, and luminosity (concentration) unevenness occurred in the picture formed had occurred. Drawings 11 and 12 are figures for explaining this problem in more detail, and it is a figure in which both figures show the figure in which it is a representative circuit schematic in which (a) contains an electronic discharge element, wiring resistance, and a power supply, and (b) shows the potential of the anode of each electronic discharge element, and a cathode, and the voltage on which (C) is impressed between the positive/negative poles of each element. Drawing 11 (a) shows the circuit which connected N electronic discharge element DI -DH(s) by which multiple connection was carried out, and power supplies VE, and connects the cathode of a power supply, and the cathode of element ON for the anode of a power supply, and the anode of element D1 again. The common wiring which connects each element in parallel shall have the resistance of r between the elements which adjoin as shown in a figure. (In the image forming device, the pixel used as the target of an electron beam is arranged by Pitch, such as usual.) Therefore, an electronic discharge element also has regular intervals spatially, and is arranged, and the wiring which connects these has equal resistance between elements, unless width and film thickness vary on manufacture. All the electronic discharge element D1~DH(s) shall carry out Hub etc., shall be, and shall have resistance Rd respectively again. Drawing 11 (b) showed the potential of the anode of each element, and the cathode in the circuit diagram of above-mentioned Drawing 11 (a). - seal with which the horizontal axis of a figure shows the element number of DI-ON, and a vertical axis shows potential expresses the anode potential of each element, ■ seal expresses cathode potential, and in order to make the tendency of potential distribution legible, the fist mark (l seal) is connected with the solid line to 1 expedient target. The voltage drop by wiring resistance r does not necessarily happen to - appearance, and, in by the side of an anode, it is so steep [ it is so steep that it is close to element DI, and ] that it is conversely close to element D11 in the cathode side so that clearly from this figure. This is for big current to flow, so that it has large current which flows through wiring resistor r, so that it is close to mouth 1 in the anode side and it is close to DN in the cathode side. In order that the horizontal axis of 0 figure which is Drawing 11 (C) may show the element number of Ill~DN, a vertical axis may show impressed electromotive force respectively and having, plotted the voltage impressed between the positive/negative poles of each element from now on may make a tendency legible like Drawing 11 (b), 0 is connected with the solid line for convenience. In the case of a circuit as shown in Drawing 11 (a), such big voltage is impressed, and impressed electromotive force becomes small with the element near the central part that it is close to the element (DI and ON) of both ends so that clearly from this figure. Therefore, the electron beam emitted from each electronic discharge element, When beam current became large and the element of both ends is applied to an image forming device, Very inconvenient being shown in Drawing 12 on the other hand (for example, the picture of the portion near both ends will have deep concentration, and the concentration near the central part will become light.) is a case where the positive/negative pole of a power supply is connected to one side (this figure the * element DI side) of the element array by which multiple connection was carried out. In the case of such a circuit The voltage drop by wiring resistance r becomes large, so that the anode and cathode side is close to Dl, as shown in the figure (b). Therefore, the voltage impressed to each element will become so big that it is close to D as shown in the figure (C), and is very inconvenient for applying as one image forming device. as mentioned above -- although the grade of the variation in the impressed electromotive force for every [ as shown in two examples ] element changes with total N of the element by which multiple connection is carried out, the ratio (= Rd/r) of element resistance Rd to wiring resistance r, or connection positions of a power supply The variation of variation in the voltage on which it becomes remarkable and the connection method of Drawing 12 is impressed to an element rather than Jinggang 11 figure is so large that Rd/r is so small that N is generally large. For example, it is Vsax about the biggest element of that Applied voltage, and the smallest element at the conjunctive of Drawing 11 [ element resistance Rd=1 / case of omega and r= 10 mohm / N= 100 Te ]. : Although it is about Vmin= 102:100, N = it is Vsax if it is 1000. : Vsin = the rate of 472:100 and variation becomes large. In wiring resistance of N = 1000. Rd= l komega and r= 1-mohm, it is Vsax. : Vmin = although it is about 127:100, if wiring resistance is set to r = 10mohm, the grade of variation will become large like about v@aX:Vsin= 472:100. As explained above, when multiple electronic discharge elements with the equal characteristic are connected to parallel, Because of the voltage drop which arises by wiring resistance, the voltage effectually impressed to each element was inconvenient, when it varied for every element, the burst size of an electron beam became uneven and it applied as an image forming device. When it was going to realize a mass display with many (N is large) pixels especially, the rate of the above-mentioned variation became remarkable and had become the problem that the concentration unevenness of a picture was big.

It is the present invention because of the means for solving [subject, and one or more-operation problem solution, A target is made to be irradiated with an equal quantity of an electron by providing the abnormal-conditions grid for controlling the passage and interception of an electron beam which are emitted from each electronic discharge element, and changing the pulse width of the voltage pulse to impress for every abnormal-conditions grid from every element. That is, when an electronic discharge element is wiring as shown in above-mentioned Drawing 11, pulse width of a central grid is made longer than both ends, and, in wiring as shown in above-mentioned Drawing 12, pulse width is lengthened as a grid far from the electric supply side of an element.

[Example] Hereinafter, an example explains the present invention. 1st [ The ] figure~figure 7 expresses one example of the present invention. Hereinafter, order is explained for operation of the device in this example later on. Drawing 1 shows the structure of the display panel, VC in a figure is a glass vacuum vessel, and FP which is the part shows the faceplate by the side of a display surface. A transparent electrode made from ITO, for example is formed in the inside of faceplate FP, further, red and a green and blue fluorescent substance are distinguished by different color by the inner side with in the shape of a mosaic, and publicly known metal back processing is performed to it in the field of CRT. (A transparent electrode, a fluorescent substance, and the metal back are not shown.) The above-mentioned transparent electrode is electrically connected the outside of a vacuum vessel through terminal EV again, in order to impress accelerating voltage. S is the glass substrate fixed to the bottom of the above-mentioned vacuum vessel VC, and arrangement formation of the electronic discharge element is carried out over the N piece xbeta sequence on the upper surface. Multiple connection of the electronic discharge element group is electrically carried out for every sequence. The anode side wiring (the cathode side wiring) of each sequence is terminal Dp, -D, and j. (terminal D1~D-1) It is electrically connected outside of a vacuum vessel. That is, in this device, the element array by the conjunctive of Drawing 11 (a) covers four rows, and is formed on substrate S. (The number of elements per row is N m.) Stripe-like grid electrode GR is provided in the middle of substrate S and face play FP again. The above-mentioned element array and grid electrode GR cross at right angles, and is provided N. Hole Gh for penetrating an electron beam is provided in each electrode. Each grid electrode which may provide one hole Gh at a time like the example of Drawing 1 corresponding to each electronic discharge element, or may provide many minute holes in mesh state is electrically connected by terminal G1~GN the outside of a vacuum vessel. XY matrix is constituted by the electronic discharge element array of intimacy, and eight grid electrode sequences by this panel. By impressing simultaneously the abnormal-conditions signal for picture 1947 minutes to a grid electrode sequence synchronizing with carrying out the line [ every ] sequential drive (scan) of the electronic discharge sequence, the irradiation to the fluorescent substance of each electron beam is controlled, and it displays one picture of one line at a time. What is shown in Drawing 2 is what showed the electric circuit for driving the display panel of above-mentioned Drawing 1 with the block diagram, About 10-kV accelerating voltage is supplied to the display panel in which l was shown in Drawing 1, and electrode terminal EV of 0 display-panel [ an abnormal-conditions grid drive circuit and whose 4 2 is high-voltage power supplies as for an element array drive circuit and 3 ] l from high-voltage power supply 4, for example. The cathode side wire terminal (0, 1~low 1) of an electronic discharge element array is grounded by the grand level (OV), and the wire terminal (Dp+~Dpl) by the side of an anode is connected with element array drive circuit block 2. The grid electrode is connected with abnormal-conditions grid drive circuit 3 through terminal Gl -GN. From element array drive circuit 2 and abnormal-conditions grid drive circuit 3, signal voltage is outputted to the timing shown in the drive time chart of Drawing 3. Although (a) in the 3rd figure~ (d) shows the signal impressed to DIInDp2.Dp3+ of panel l, and Dp7 terminal from element array drive circuit 2, as a figure showing -- not -- +DP2 + 0113 ... (D and 4"'DIl (j-1) are figure Nakaji) Dpr In order of (7), the drive pulse of amplitude VEV is impressed one by one. It synchronizes with this and is from abnormal-conditions grid drive circuit 3, It is abnormal-conditions signal (VG (--) or VG (OFF)) (Apply J'L 6, carrying out each terminal D pair) > at the timing shown in Drawing 3 (e) and (f) to terminal Gl-GN. Ve Or [ that a (on-) level is impressed / Ve ] It is decided by the pattern of a display picture whether (OFF) a level will be impressed. however, here -- being careful -- it is that the pulse width which impresses VG (ON) for every terminal differs. (In the figure, in order to make a drawing brief, only two examples of GN/[ G+ (pulse width is PL (1)) and ] 2 (pulse width is PL (N/2)) are examples.) In order to explain this in more detail, the pulse width of the voltage impressed to each grid electrode is shown in Drawing 4. In the figure, with 1 device, the central grid (GN/2) of the width of impress pulses is the largest, and the horizontal axis is so small that both-ends CG+ and GM are approached so that clearly from 0 figures showing the pulse width of the voltage to which a vertical axis impresses each grid electrode. In 0 devices which set this maximum to PL (N/2), and set the minimum to PL (1), the good display which does not have luminosity (concentration) unevenness over the whole surface of a screen is obtained by changing the pulse width which impresses VG (ON) potential in this way for every grid. It. It is based on a principle which is explained below. That is, it is although the example of the impressed-electromotive-force Ma S output current characteristic of the electronic discharge element used with this device is shown in Drawing 5, In the element by which multiple connection was carried out as the paragraph of the problem described conventionally (refer to Drawing 11 (c)), If the maximum of impressed electromotive force is set to V■ax and the minimum is set to Vain in 0 (C) used as the value which differed also in output beam current for every element, for example, Drawing 11, since impressed electromotive force shows variation for every element, Output beam current will take either value more than EB@ i n and of below EBsax by an element from the characteristic of Drawing 5. . However, as shown in Drawing 6, even if the output beam current of an element differs, it is possible to make equal quantity of the electron per l pulse which arrives at a fluorescence side by making into suitable length pulse width of the voltage impressed to an abnormal-conditions grid. That is, if pulse width of grid impressed electromotive force is set to PL (1) to an element with the biggest output beam current and width impresses the voltage of the pulse of PL (N/2) to an element with the smallest output beam current, quantity of the electron per pulse which arrives at a fluorescence side can be made equal. In Drawing 6, although two examples of EBsax and EBsin were explained, if pulse width which makes equal quantity of the electron which arrives at a fluorescence side about all the elements is shown, it will become as it is shown in above-mentioned Drawing 4. In order to impress the pulse of different width as shown in Drawing 4 to each grid, a circuit as shown, for example in Drawing 7 may be used as an abnormal-conditions grid drive circuit. As for a serial-parallel-conversion machine and 6, a switching transistor and 9.10.11 are pulse generators an inverter, and 7 and 8 respectively 5 in Drawing 7. Serial-parallel-conversion machine 5 accumulates the image data serially sent from the outside by one line (N pieces), and outputs it from PI -PM in parallel to predetermined timing. Although H level (high level) or L level (low level) is respectively outputted individually with the data of 1 display picture from PI~PN, when H level is outputted, the pulse of length explained from the connected pulse generator in above-mentioned Drawing 4 is outputted. While the pulse is outputted, transistor 7 serves as * ON and transistor 8 serves as OFF, and it is vc to the terminal of a grid electrode. A voltage pulse with the wave high price of (ON) is outputted. Since a pulse is not outputted from a pulse generator when the output of serial-parallel-conversion machine 5 is L level, transistor 7 serves as OFF, transistor 8 is set to ON, and - constant potential of Vc (OFF) is impressed to the terminal of a grid electrode. As a pulse generator used all over the above-mentioned circuit, the pulse width of each generator can be set up by choosing suitable RC in that case, for example like one shot multi-vibrator. It is possible to constitute easily the pulse generator which outputs predetermined pulse width also from other than one shot multi-vibrator, if digital circuits, such as an oscillator, a counter, and a comparator, are combined. Although the example of the image forming device to which the present invention is applied above was described, The pulse width of the voltage impressed to a grid electrode is a grid electrode near both ends (G+ and GN) so that it may be shown in 0 which is not what is limited to the example shown in above-mentioned Drawing 4, for example, Drawing 8, This which may drive with individually different pulse width like above-mentioned Drawing 4, may cross the grid electrode near the central part (GN/2) to several, and may use the same pulse width is the method that it is suitable when the rate of luminosity (e times) unevenness has the small central part compared with a circumference part. When the homogeneity of luminosity is not required so strictly by application and a use, For example, as shown in Drawing 9, since the method of above-mentioned Drawings 8 or 9 which may be driven with the same pulse width to a plurality of grids can reduce the kind of pulse width to be used as compared with the example of above-mentioned Drawing 4, it has a merit which can decrease the number of pulse generators. It is although the wiring method of an electronic discharge element is a method about the case of Drawing 11 explained according to the conventional example in the example which it is above, the case where 0 [ overemphasize / that the grid impressed electromotive force of the 1 present invention also differs when the wiring methods of an electronic discharge element differ ], for example, a wiring method as shown in Drawing 12 of a conventional example, is performed -- the -- it is suitable to lengthen pulse width, so that it is close to ON, as shown in theta [ 1 ] figure.

[Effect of the Invention] As explained above, it is possible not to depend the quantity of the electron per l pulse which arrives at a fluorescence side on an element, but to make it uniform by making into different length pulse width of the voltage impressed to a grid in the present invention according to the variation in the electron beam current to which it is emitted from an electronic discharge element. The luminosity (concentration) unevenness of the picture which had become a problem conventionally can be canceled by this, and it is .. Practicality Suk of the mass display of a large area was able to be sharply improved in the thin form. To most image forming devices which have the electron source which carried out multiple connection of many electronic discharge elements in addition to the monotonous type display as shown in the example, it can apply, for example, application of the present invention is very effective also in the field of an electron beam drawing device or an image recorder.

[Brief Description of the Drawings]

Drawing 1 is a perspective view of the display panel portion of the image forming device to which the present invention is applied, The block diagram of the drive circuit of the image forming device with which Drawing 2 applied the present invention, the drive time chart of the image forming device with which Drawing 3 applied the present invention, Drawing 4 is a figure showing the pulse width of the grid electrode drive voltage of the image forming device to which the present invention is applied, The figure showing the characteristic of the electronic discharge element which used Drawing 5 in the example, the figure showing the operating characteristic of an abnormal-conditions grid [ in / in Drawing 6 / the present invention ], the figure in which Drawing 7 shows an abnormal-conditions grid drive circuit, Drawing 8, Drawing 9, and Drawing 10 are figures showing the pulse width of the drive voltage of the grid electrode as other examples. Drawing 11 and Drawing 12 are figures showing the representative circuit schematic of the present invention, and the potential and voltage of the component. l ... Display panel 2 [ ... High-voltage power supply ] ... Element array drive circuit 3 ... Abnormal-conditions grid drive circuit 4 5 ... Serial-parallel-conversion machine 6 ... Inverter 7.8 ... switching transistor 9, 10.11 ... pulse generator