Patent Publication Number: US-7903075-B2

Title: Image display apparatus

Description:
CLAIM OF PRIORITY 
     The present application claims priority from Japanese application JP 2005-040016 filed on Feb. 17, 2005, the content of which is hereby incorporated by reference into this application. 
     FIELD OF THE INVENTION 
     The invention relates to an image display apparatus with a portion of a display substrate area, around a display section, being small, low in power consumption, and capable of effecting high-definition image display. 
     BACKGROUND OF THE INVENTION 
     A conventional technology is described hereinafter with reference to  FIG. 12 . 
     To start with, a structure according to a first example of the conventional technology is described.  FIG. 12  is a circuit configuration diagram of a liquid crystal display using the conventional technology. Respective pixels of a display section  216  include a pixel switch  211  and a liquid crystal capacitor  212 , and an opposite electrode of the liquid crystal capacitor  212  is connected to a common power supply line  217 . The gate of the pixel switch  211  is connected to a vertical scanning circuit  215  via a gate line  214 , and one end of the pixel switch  211  is connected to a DA conversion circuit  209  via a signal line  213 . 
     An output of a latch circuit  208  is delivered to the digital/analogue (DA) conversion circuit  209  and an output of a sense amplifier  207  is delivered to the latch circuit  208 . A signal from one end of a data line  203  is delivered to the sense amplifier  207 . The data lines  203  are provided with the memory cells  221 , respectively, the memory cells  221  being arranged in matrix fashion. As with memory cells of a DRAM (Dynamic Random Access Memory), the memory cells  221  each include one transistor switch and one capacitor (hereinafter referred to as “a 1T 1C configuration”), that is, a memory switch  201  and a memory capacitor  202 , and the gate of the memory switch  201  is connected to a memory select circuit  205  via a memory gate line  204 . The other end of the data line  203  is connected to a data input circuit  206 . 
     Next, an operation of the first example of the conventional technology is described. 
     As a result of the memory select circuit  205  turning ON the memory switches  201  in a predetermined row via the memory gate line  204 , memory data is read, and a signal thereof is amplified by the sense amplifier  207  to be subsequently written into the latch circuit  208 . At this point in time, the memory select circuit  205  repeatedly reads the memory cells  221  corresponding to n-rows, thereby enabling the latch circuit  208  to read image data of n-bits. 
     The image data of n-bits as read is outputted from the latch circuit  208  to the DA conversion circuit  209 , which converts the image data of n-bits into one analogue signal voltage to be then outputted to the signal line  213 . At this point in time, the vertical scanning circuit  215  turns ON the pixel switch  211  at a predetermined address via the gate line  214 , whereupon the analogue signal voltage is written into the liquid crystal capacitor  212  of the pixel as selected, thereby optically effecting image display. 
     In this connection, because the signal amplified by the sense amplifier  207  is written into the data line  203  as well, refresh operations of the memory cells are concurrently executed at this point in time. 
     With the conventional technology, image display can be effected without new input of image data from outside, so that low power consumption display can be effected with a peripheral drive circuit kept in a sleep condition. 
     Such an example of the conventional technology as described, is disclosed in detail in, for example, JP-A No. 085065/1999. 
     Further, with the example of the conventional technology, a memory cell layout is described again with reference to  FIG. 13 .  FIG. 13  is a layout plan of the memory cells according to the first example. 
     One analogue image signal is stored by use of the memory cells  221  for n pieces (six pieces in  FIG. 13 ), disposed in the column direction along each of the data lines  203 . Accordingly, at the time of outputting data on one analogue image signal, corresponding to one word, it is necessary to output n pieces of data by scanning n lengths of the memory gate lines  204 . 
     The memory cell layout according to the example of the conventional technology is disclosed in, for example, JP-A No. 085065/1999, and so forth, as described in the foregoing. 
     Meanwhile, another memory cell layout according to a second example of the conventional technology is described with reference to  FIG. 14 . 
       FIG. 14  is a layout plan of memory cells according to the second example of the conventional technology. 
     It represent the case where one analogue image signal is stored by use of the memory cells  221  for n pieces (six pieces in  FIG. 14 ), disposed in the row direction along each of the memory gate lines  204 . Accordingly, at the time of outputting data on one analogue image signal, corresponding to one word, it is necessary to obtain n pieces of data outputted to n lengths of the data lines  203 . 
     The memory cell layout according to the example of the conventional technology, as described above, is disclosed in detail in, for example, JP-A No. 082656/2002, and so forth. 
     SUMMARY OF THE INVENTION 
     With the liquid crystal displays according to the examples of the conventional technology, problems have remained in respect of a memory cell layout although those liquid crystal displays are capable of effecting display at low power consumption. 
     A configuration of the first example of the conventional technology, shown in  FIG. 13 , has a problem in that as a result of an increase in the number of bits for the image data, it has been impossible to reduce a portion of a display substrate area, around a display section. This is because the number of the memory cells in the direction of the data line comes to increase along with the increase in the number of bits for the image data, thereby resulting in an increase in circuit width of a memory section. 
     Further, a configuration of the second example of the conventional technology, shown in  FIG. 14 , has a problem in that as a result of an increase in the number of bits for the image data, it becomes difficult to implement higher definition for the pixels. This is because the number of the memory cells to be disposed in a width for the pixels comes to increase along with the increase in the number of bits for the image data, so that it becomes difficult to reduce the width for the pixels less than a given size. 
     It is therefore an object of the invention to provide an image display apparatus with a portion of a display substrate area, around a display section, being small, low in power consumption, and capable of effecting high-definition image display. 
     An example of representative means of the invention, disclosed in the present specification, is shown as follows. 
     That is, the invention provides an image display apparatus including a display section where plural pixels are arrayed, an analogue image signal generation means for generating an analogue image signal to be inputted to the pixels on the basis of a digital image signal, and an image signal storage means for storing the digital image signal, the constituents being provided over one and the same insulating substrate, wherein the image signal storage means includes a memory cell array with memory cells disposed in matrix fashion, the memory cells being selected by respective select metal interconnects disposed in a row direction, and the digital image signal is inputted/outputted by respective signal metal interconnects disposed in a column direction while the analogue image signal generation means generates one unit of the analogue image signal on the basis of the digital image signal selected by not less than two lengths of the select metal interconnects, and outputted by not less than two lengths of the signal metal interconnects. 
     With the invention, because a memory and the display section are provided over one and the same substrate, it is possible to provide the image display apparatus with the portion of the display substrate area, around the display section, being small, low in power consumption, and capable of effecting high-definition image display. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a circuit configuration diagram of a liquid crystal display according to a first embodiment of the invention; 
         FIG. 2  is a memory cell layout base circuit diagram the according to the first embodiment; 
         FIG. 3  is a circuit configuration diagram showing a sense amplifier circuit and a latch circuit, according to the first embodiment; 
         FIG. 4  is a timing chart showing an operation of memory cells according to the first embodiment; 
         FIG. 5  is a layout view of a memory cell section according to the first embodiment; 
         FIG. 6  is a sectional view showing a structure of a portion of the memory cell section, taken on line A-B, shown in  FIG. 5 ; 
         FIG. 7  is a circuit configuration diagram showing a sense amplifier circuit and a latch circuit, according to a second embodiment; 
         FIG. 8  is a timing chart showing an operation of memory cells according to the second embodiment. 
         FIG. 9  is a memory cell layout base circuit diagram according to a third embodiment; 
         FIG. 10  is a circuit configuration diagram of an organic EL display according to a fourth embodiment; 
         FIG. 11  is a block diagram of a TV image display apparatus according to a fifth embodiment; 
         FIG. 12  is a circuit configuration diagram of a liquid crystal display using a conventional technology; 
         FIG. 13  is a layout plan of memory cells according to a first example of the conventional technology; and 
         FIG. 14  is a layout plan of memory cells according to a second example of the conventional technology. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of an image display apparatus according to the invention are described in detail hereinafter with reference to the accompanying drawings. 
     First Embodiment 
     A configuration and an operation of a first embodiment of an image display apparatus according to the invention are described in sequence hereinafter with reference to  FIGS. 1 to 6 . 
       FIG. 1  is a circuit configuration diagram of a liquid crystal display according to the first embodiment of the invention. Respective pixels of a display section  16  include a pixel switch  11  and a liquid crystal capacitor  12 , and an opposite electrode of the liquid crystal capacitor  12  is connected to a common power supply line  17 . The gate of the pixel switch  11  is connected to a vertical scanning circuit  15  via a gate line  14 , and one end of the pixel switch  11  is connected to a DA conversion circuit  9  via a signal line. 13 . 
     An output of a latch circuit  8  is delivered to the DA conversion circuit  9 , an output of a sense amplifier  7  is delivered to the latch circuit  8 , and a signal from one end of a data line  3  is delivered to the sense amplifier  7 . The data lines  3  are provided with memory cells  21 , respectively, the memory cells  21  being arranged in staggered fashion. The memory cell  21  also is connected to a memory select circuit  5  via a memory gate line  4 . The other end of the data line  3  is connected to a data input circuit  6 . 
     Further, a memory cell layout circuit according to the present embodiment is more specifically described hereinafter with reference to  FIG. 2 . 
       FIG. 2  is a memory cell layout base circuit diagram the according to the present embodiment. 
     As with the memory cells of the DRAM of the 1T1C configuration, the memory cells  21  each include a memory switch (transistor)  1  and a memory capacitor  2 , the gate of a memory switch  1  is connected to the memory gate line  4 , and one end of the memory switch  1  is connected to the data line  3 . Further, one end of the memory capacitor  2  is connected to the memory gate line  4  for the memory cell adjacent thereto. Now, as shown in  FIG. 2 , the memory cells in odd columns, corresponding to the data lines  3   a ,  3   c , respectively, and the memory cell in even column, corresponding to the data line  3   b , are disposed so as to be staggered against each other. Further, the memory cells are disposed so as to be vertically symmetrical in the direction of the data line  3  with respect to a contact between the respective memory cells, and the data line  3 . Further, in  FIG. 2 , the English alphabet letters, such as  4   a ,  4   b ,  4   c ,  4   d ,  4   e ,  4   f ,  4   g , and  4   h , are suffixed to the respective memory gate lines  4 , and the English alphabet letters, such as  3   a ,  3   b , and  3   c , are suffixed to the respective data lines  3 . This is for the purpose of explanation to be described later on with reference to  FIG. 4 . 
     Next, respective configurations of the sense amplifier  7 , and the latch circuit  8 , according to the present embodiment, are more specifically described with reference to  FIG. 3 . 
       FIG. 3  is a circuit configuration diagram showing respective internal basic circuits of the sense amplifier  7 , and the latch circuit  8 , according to the present embodiment. The internal basic circuit of the sense amplifier  7  includes an inverter  31 , a short-circuiting switch  32  for short-circuiting input/output of the inverter  31 , and a feedback clocked inverter  33  to be controlled by a clock ckA, for feed backing the output of the inverter  31 , and the internal basic circuit of the sense amplifier  7  corresponds to one pixel of six bits, six pieces of the internal basic circuits being provided for each of the sense amplifiers  7 . 
     The internal basic circuit of the latch circuit  8  includes a clocked inverter  34  to be controlled by a clock ckB 1  for executing latch sampling, an inverter  35  for temporarily storing data as sampled, and a feedback clocked inverter  36  to be controlled by a clock ckB 2 , and the internal basic circuit of the latch circuit  8  also corresponds to one pixel of six bits, six pieces of the internal basic circuits being provided for each of the latch circuits  8 . Further, an output of the latch circuit  8  is delivered to the DA conversion circuit (DAC)  9 , but the DA conversion circuit  9  adopted in this case has a common circuit configuration, and DA conversion circuits of various configurations have thus far been reported, omitting therefore a description thereof. 
     Next, an operation of the present embodiment is described hereinafter. 
     A basic operation of the present embodiment is similar to that of the example of the conventional technology as previously described. That is, as a result of the memory select circuit  5  turning ON the memory switches  1  in a predetermined row via the memory gate line  4 , memory data is read, and a signal thereof is amplified by the sense amplifier  7  to be subsequently written into the latch circuit  8 . Image data of six bits, as read, is outputted from the latch circuit  8  to the DA conversion circuit  9 , and the DA conversion circuit  9  converts the image data of six bits into one analogue signal voltage to be then outputted to the signal line  13 . At this point in time, the vertical scanning circuit  15  turns ON the pixel switch  11  at a predetermined address via the gate line  14 , whereupon the analogue signal voltage is written into the liquid crystal capacitor  12  of the pixel as selected, thereby optically effecting image display. Further, because the signal amplified by the sense amplifier  7  is written into the data line  3  as well, refresh operations of the respective memory cells are concurrently executed at this point in time. 
     With the present embodiment, however, for read-out of the image data of six bits, two lengths of the memory gate lines  4  are concurrently driven, and respective outputs of six lengths of the data lines  3  are concurrently fetched. 
     Next, the operation of the present embodiment is more specifically described with reference to  FIG. 4 . 
       FIG. 4  is a timing chart showing an operation of the memory cells  21  according to the present embodiment. As indicated by the arrows at respective ends of a shaft, shown in the figure, the upper side in the figure indicates that the respective switches or gates are in the on-condition while the lower side in the figure indicates that the respective switches or gates are in the off-condition. 
     It will be described hereinafter that the data is read from the memory capacitors  2   b ,  2   d  by scanning the memory gate lines  4   b ,  4   d , respectively. 
     First, when the short-circuiting switches  32  of the respective sense amplifiers  7  are turned ON, the input/output of the inverter  31  as short-circuited, will be at an intermediate voltage between high (HI) and low (LOW), thereby resetting the data lines  3  to an intermediate voltage. 
     Subsequently, if the memory gate lines  4   b ,  4   d  are concurrently turned ON/OFF after the short-circuiting switches  32  are turned OFF, the data is read from the memory capacitors  2   b ,  2   d  to the respective data lines  3  to thereby modulate potentials of the respective data lines  3 . At this point in time, the outputs of the respective inverters  31  are turned ON/OFF according to the data read by the respective data lines  3 , results of which are fed back to the respective data lines  3  due to the feedback clocked inverter  33  being turned ON by the agency of the clock ckA. 
     Further, if the memory gate lines  4   b ,  4   d  are concurrently turned ON/OFF at this point in time, the memory data fed back to the respective data lines  3  is again written into the memory capacitors  2   b ,  2   d , thereby implementing a refresh operation as with the case of the DRAM. Meanwhile, at this point in time, by turning OFF the feedback clocked inverter  36  by the agency of the clock ckB 2 , and subsequently, by turning ON the clocked inverter  34  to be controlled by the agency of the clock ckB 1 , it is possible to fetch the output of the inverter  31  into the inverter  35  inside the latch circuit  8 . 
     Thereafter, after the feedback clocked inverter  36  is turned ON by the agency of the clock ckB 2 , the clocked inverter  34  to be controlled by the clock ckB 1  is turned OFF to thereby complete this latch operation, and by concurrently turning OFF the feedback clocked inverter  33  by the agency of the clock ckA, preparation for reading the following memory data is executed. 
     The above operation completes read-out of the memory data corresponding to one pixel row from the memory capacitors  2   b ,  2   d  by scanning the memory gate lines  4   b ,  4   d , respectively, followed by starting read-out of memory data corresponding to a succeeding pixel row from the memory capacitors  2   c ,  2   e  by scanning the memory gate lines  4   c ,  4   e , respectively. 
     Thereafter, that image data as read is converted into analogue signal voltages by the DA conversion circuit  9  to be then written into the respective pixels, thereby effecting optical display. Such an operation, however, is a generally well-known operation as with the example of the conventional technology, omitting therefore a description thereof. 
     In this case, the memory gate lines  4   b ,  4   d  are turned ON/OFF twice, which is for the purpose of avoiding the effect of feed-through of the memory switches  1  at the time of the inverter  31  sensing a read-out signal by temporarily turning OFF the memory switches  1  as selected. Accordingly, if the effect of the feed-through of the memory switches  1  is sufficiently small, the memory gate lines  4   b ,  4   d  can be turned ON/OFF once altogether without turning OFF the memory gate lines  4   b ,  4   d  at the time of sensing. 
     With the present embodiment, for read-out of the image data of six bits, two lengths of the memory gate lines  4  are concurrently driven, and respective outputs of six lengths of the data lines  3  are concurrently fetched. Thus, by concurrently driving two lengths of the memory gate lines  4 , the memory cells can be disposed on a layout of higher density as compared with that for the example of the conventional technology, shown in  FIG. 14 . 
     The above operation is further described hereinafter with reference to  FIG. 5 . 
       FIG. 5  is a plan view showing a layout of a memory cell section. In  FIG. 5 , a broken line indicates the data line  3  of a metal interconnect, a thick line indicates the memory gate line  4 , a thin line indicates a channel layer  41  formed of polycrystalline-Si, and a square delineated by a thick line indicates a contact hole  40  between the data line  3  and the channel layer  41  of polycrystalline-Si. As is evident from the figure, in order that mating allowance from a yield point of view is secured around the contact hole  40 , the data line  3  of the metal interconnect, indicated by the broken line, need be provided with dog-bones, however, with the present embodiment, since the respective memory cells in even columns are disposed in staggered fashion against the respective memory cells in odd columns, the dog-bone can be sufficiently laid out while securing the allowance between the data lines  3  adjacent to each other. 
       FIG. 6  is a sectional view showing a structure of a portion of the memory cell section, taken on line A-B, shown in  FIG. 5 . Over the same glass substrate  44  where the pixels for the liquid crystal display, the DA conversion circuits  9 , and so forth are disposed, there are provided the memory switches  1  each made up of a TFT (Thin Film Transistor), and the memory capacitors  2 , using the memory gate lines  4 , and the channel layer  41  formed of polycrystalline-Si, as with the pixels for the liquid crystal display, the DA conversion circuits  9 , and so forth, and further, there are formed an interlayer dielectric  45 , and the data line  3  formed of the metal interconnect. Those devices are implemented by adoption of an n-channel type MOS (Metal Oxide Semiconductor) structure. 
     With the structure described as above, a variation thereto is possible wherein the channel layers  41  of polycrystalline-Si, adjacent to each other, are connected together in the column direction in an attempt for higher density, or a light-leak current is reduced by providing a light blocking layer underneath the memory cells, and so on. 
     Further, with the present embodiment, the TFT inside the respective memory cells is the nMOS transistor formed of polycrystalline-Si, however, if polarities of respective control voltages are reversed, a pMOS transistor can be used as appropriate, and the constituent material of the transistor is not limited to polycrystalline-Si, so that other organic/inorganic semiconductor thin-films can be used for the transistor. 
     Second Embodiment 
     A second embodiment of an image display apparatus according to the invention is described hereinafter with reference to  FIGS. 7 and 8 . 
     A liquid crystal display according to the present embodiment is basically similar in configuration and operation to the first embodiment. The present embodiment, however, differs from the first embodiment in respect of its configuration around a sense amplifier  53 , and operation timing of memory cells, and those points are therefore described hereinafter. 
       FIG. 7  is a circuit configuration diagram showing respective internal basic circuits of the sense amplifier  53 , and a latch circuit  8 , according to the present embodiment. The internal basic circuit of the sense amplifier  53  includes an inverter  31 , a short-circuiting switch  32  for short-circuiting input/output of the inverter  31 , and a feedback clocked inverter  33  to be controlled by a clock ckA, for feeding back the output of the inverter  31 , and the internal basic circuit of the sense amplifier  53  corresponds to one pixel of six bits, three pieces of the internal basic circuits being provided for each of the sense amplifiers  53 . Further, an input terminal and an output terminal of the internal basic circuit of the sense amplifier  53  are provided with an input changeover switch  51 , and an output changeover switch  52 , respectively. 
     The internal basic circuit of the latch circuit  8  includes a clocked inverter  34  to be controlled by a clock ckB 1 , for executing latch sampling, an inverter  35  for temporarily storing data as sampled, and a feedback clocked inverter  36  to be controlled by a clock ckB 2 , and the internal basic circuit of the latch circuit  8  also corresponds to one pixel of six bits, six pieces of the internal basic circuits being provided for each of the latch circuits  8 . The latch circuit  8  is similar in configuration to that for the first embodiment. 
     Next, an operation of the present embodiment is described hereinafter. 
     A basic operation of the present embodiment is similar to that of the first embodiment as previously described, omitting therefore a description thereof. With the present embodiment, however, for read-out of image data of six bits, two lengths of memory gate lines  4  are sequentially driven, and respective outputs of six lengths of data lines  3  are fetched in two steps. 
     The above operation is more specifically described with reference to  FIG. 8 . 
       FIG. 8  is a timing chart showing the operation of memory cells  21  according to the present embodiment. As indicated by the arrows at respective ends of a shaft, shown in the figure, the upper side in the figure indicates that respective switches or gates are in the on-condition while the lower side in the figure indicates that the respective switches or gates are in the off-condition. 
     It will be described hereinafter that data is read out from the memory capacitors  2   b  by scanning the memory gate line  4   b.    
     First, when the short-circuiting switches  32  of the respective sense amplifiers  53  are turned ON, the input/output of the inverter  31 , as short-circuited, will be at an intermediate voltage between HI and LOW, thereby resetting the data lines  3  to the intermediate voltage. 
     Subsequently, if the memory gate line  4   b  is turned ON/OFF after the short-circuiting switches  32  are turned OFF, the data is read from the memory capacitors  2   b  to the respective data lines  3  to thereby modulate the potentials of the respective data lines  3 . At this point in time, the outputs of the respective inverters  31  are turned ON/OFF according to the data read by the respective data lines  3 , results of which are fed back to the respective data lines  3  due to the feedback clocked inverter  33  being turned ON by the agency of the clock ckA. 
     If the memory gate line  4   b  is turned ON/OFF at this point in time, the memory data that is fed back to the respective data lines  3  is again written into the memory capacitors  2   b , respectively, thereby implementing a refresh operation as with the case of the DRAM. Meanwhile, at this point in time, by turning OFF the feedback clocked inverter  36  by the agency of the clock ckB 2 , and subsequently, by turning ON the clocked inverter  34  to be controlled by the agency of the clock ckB 1 , it is possible to fetch the output of the inverter  31  into the inverter  35  inside the latch circuit  8 . 
     Thereafter, after the feedback clocked inverter  36  is turned ON by the clock ckB 2 , the clocked inverter  34  to be controlled by the clock ckB 1  is turned OFF to thereby complete this latch operation, and by concurrently turning OFF the feedback clocked inverter  33  by the clock ckA, preparation for reading succeeding memory data is executed. 
     The above operation completes read-out of the memory data corresponding to the first half three bits of one pixel from the memory capacitors  2   b  by scanning the memory gate line  4   b , and subsequently, followed by starting read-out of memory data corresponding to the last half three bits of one pixel from the memory capacitors  2   d  by scanning the memory gate line  4   d . Prior to the above, the input changeover switch  51 , and output changeover switch  52 , provided at the input and output terminals of the sense amplifier  53 , respectively, are concurrently changed over. 
     Thereafter, the read-out of the memory data corresponding to the last half three bits of one pixel from the memory capacitors  2   d  is similarly completed, thereby completing read-out of the memory data corresponding to one pixel row. 
     Subsequently, as for memory data corresponding to a succeeding pixel row, the first half thereof is similarly read out from the memory capacitors  2   c , and the last half thereof is similarly read out from the memory capacitors  2   e . Then, read-out of memory data corresponding to a succeeding pixel row is repeated by reading out the first half of one pixel from the memory capacitors  2   f , and reading out the last half thereof from the memory capacitors  2   h.    
     With the present embodiment, a compact memory cell layout can be implemented as with the case of the first embodiment, however, since the present embodiment has an advantage in that the internal basic circuits of the sense amplifier  53 , prone to become large in circuit structure, can be used by a time division multiplex technique whereby the input changeover switch  51  and the output changeover switch  52  are switched over, there is obtained an additional advantageous effect of implementing the sense amplifier  53  compact in size. 
     Third Embodiment 
     A third embodiment of an image display apparatus according to the invention is described hereinafter with reference to  FIG. 9 . A liquid crystal display according to the present embodiment is basically similar in configuration and operation to the first embodiment. The present embodiment, however, differs from the first embodiment in respect of a memory cell layout circuit of memory cells  61 , which is therefore described hereinafter. 
       FIG. 9  is a memory cell layout base circuit diagram according to the present embodiment. 
     As with the memory cells of the DRAM of the 1T1C configuration, the memory cells  61  each include the memory switch  1  and the memory capacitor  2 . The gate of the memory switch  1  is connected to the memory gate line  4 , and one end of the memory switch  1  is connected to the data line  3 . Further, one end of the memory capacitor  2  is connected to the memory gate line  4  for an adjacent memory cell. Now, as shown in  FIG. 9 , the memory cells in three columns, corresponding to the data lines  3   a ,  3   b ,  3   c , respectively, are disposed so as to be staggered against each other. Further, the memory cells are disposed so as to be vertically symmetrical in the direction of the data line  3  with respect to a contact between the respective memory cells, and the data line  3 . 
     An operation of the present embodiment is similar to that of the first embodiment, omitting therefore a description thereof. Further, a timing chart showing operations of the memory cells  61  is also similar to the timing chart according to the first embodiment, described with reference to  FIG. 4 , omitting therefore a description thereof. 
     With the present embodiment, the memory capacitor  2  is provided above and below the memory gate lines  4 , respectively, so that it is possible to attain higher density of the memory cells as compared with the case of the first embodiment. 
     Fourth Embodiment 
     A fourth embodiment of an image display apparatus according to the invention is described hereinafter with reference to  FIG. 10 . 
     An organic EL (electroluminescence) display according to the present embodiment is basically similar in configuration and operation to the first embodiment. However, the present embodiment differs from the first embodiment in respect of display pixel configuration in that display pixels are not the liquid crystal pixels but organic EL pixels, and this is described hereinafter. 
       FIG. 10  is a circuit configuration diagram of the organic EL display according to the present embodiment. Respective pixels of a display section  82  include an organic El device  71 , an organic El drive transistor  72 , a light-up control switch  73 , a reset switch  74 , and a memory capacitor  75 , and an opposite electrode of the organic El device  71  is grounded. The light-up control switch  73  has one end connected to a power supply line  79 . The gate of the reset switch  74  is connected to a vertical control circuit  78  via a reset line  77 , and the gate of the light-up control switch  73  is connected to the vertical control circuit  78  via a light-up control line  76 . The memory capacitor  75  has one end connected to a DA conversion circuit  81  via a signal line  13 . The DA conversion circuit  81  is provided with a triangular-wave-voltage control terminal  80 , and outputs a triangular-wave-voltage in place of an image signal voltage in accordance with an instruction from the triangular-wave-voltage control terminal  80 . 
     An output of a latch circuit  8  is delivered to the DA conversion circuit  81 , an output of a sense amplifier  7  is delivered to the latch circuit  8 , and a signal from one end of each of data lines  3  is delivered to a sense amplifier  7 . The data lines  3  are provided with memory cells  21 , respectively, the memory cells  21  being disposed in staggered arrangement. The respective memory cells  21  are connected to the memory select circuit  5  via respective memory gate lines  4 . Further, the other end of each of the data lines  3  is connected to a data input circuit  6 . Thus, a circuit configuration of the present embodiment, preceding the latch circuit  8 , is similar to that for the first embodiment. 
     Next, an operation of the present embodiment concerning outputting of the signal voltage from the memory cells  21  to the respective signal lines  13  is basically similar to that for the first embodiment, as previously described, omitting therefore a description thereof. 
     However, since the present embodiment differs in respect of the pixel configuration from the first embodiment, an operation in this respect is described hereinafter. 
     When an image signal voltage is outputted to the signal lines  13 , a predetermined pixel row is selected by the vertical control circuit  78 , whereupon the light-up control switch  73  and the reset switch  74  are turned ON via the light-up control line  76  and the reset line  77 , respectively. At this point in time, input/output of an inverter circuit made up of the organic El drive transistor  72  and the organic El device  71  is held at an intermediate potential, and a difference between the intermediate potential and the image signal voltage is inputted to the memory capacitor  75 . Thereafter, the light-up control switch  73  and the reset switch  74  are turned OFF, with the result that the difference between the intermediate potential and the image signal voltage is stored in the memory capacitor  75 . 
     Thus, after completion of writing of the image signal voltage to all the pixels to be displayed, the DA conversion circuit  81  outputs the triangular-wave-voltage in place of the image signal voltage to the signal lines  13  in accordance with the instruction from the triangular-wave-voltage control terminal  80 . At this point in time, the vertical control circuit  78  turns ON the light-up control switches  73  for all the pixels via the light-up control line  76 . As a result, the respective pixels modulate a light-up period of the organic El device  71  depending on whether or not a prewritten image signal voltage is equivalent to the triangular-wave-voltage, thereby enabling optical image display to be executed. 
     The configuration and operation of the organic EL display described as above are disclosed in detail in JP-A No. 005709/2003, JP-A No. 122301/2003, and so forth. 
     Further, with the present embodiment, a light emitting device is not limited to the organic El device, and a common light emitting device, such as an inorganic El device, FED (Field-Emission Device), and so forth, can be obviously used as the light emitting device. With the present embodiment, a detailed description of a luminescence layer is omitted because the same does not represent the essence of the invention, however, various molecular structures such as a low-molecular type, polymer type and so forth can be adopted for an organic El device structure. 
     Further, with the present embodiment, the opposite electrode of the organic El device  71  is grounded, but the potential thereof need not necessarily be at 0V, and it goes without saying that the potential of the organic El device, including polarity thereof, may be altered as necessary. 
     Fifth Embodiment 
     A fifth embodiment of an image display apparatus according to the invention is described hereinafter with reference to  FIG. 11 . 
       FIG. 11  is a block diagram of a TV image display apparatus  100  according to the present embodiment. 
     Compressed image data, and so forth are inputted as wireless data from outside to a wireless interface (I/F) circuit  102  for receiving ground wave digital signals and so forth, and an output of the wireless I/F circuit  102  is connected to a data bus  108  via an I/O (input/output) circuit  103 . A microprocessor (MPU)  104 , a display panel controller (CTL)  106 , a frame memory (MM)  107 , and so forth, besides the above-described, are connected to the data bus  108 . Further, an output of the display panel controller  106  is inputted to a liquid crystal display panel  101 . In addition, an out-of-panel 10V generation circuit (PWR 10V)  109  and an out-of-panel 5V generation circuit (PWR 5V)  110  are provided inside the TV image display apparatus  100 . Now, the liquid crystal display panel  101  is basically identical in configuration and operation to the liquid crystal display panel according to the first embodiment previously described, omitting therefore a description of an internal configuration and operation thereof. 
     An operation of the present embodiment is described hereinafter. First, the wireless I/F circuit  102  fetches the compressed image data from outside according to an instruction, and transfers the image data to the microprocessor  104  and the frame memory  107  via the I/O circuit  103 . Upon receiving an operation instruction from a user, the microprocessor  104  drives the TV image display apparatus  100  in whole as necessary to thereby execute decoding of the compressed image data, signal processing, and information display. At this point in time, the image data after the signal processing can be temporarily stored in the frame memory  107 . 
     In the case where the microprocessor  104  issues a display instruction at this point in time, the image data is inputted from the frame memory  107  to the liquid crystal display panel  101  via the display panel controller (CTL)  106  in accordance with the instruction, whereupon the liquid crystal display panel  101  displays the image data as inputted in real time. At this point in time, the display panel controller (CTL)  106  outputs a predetermined timing pulse necessary for simultaneously displaying images while the out-of-panel 10V generation circuit (PWR 10V)  109  and the out-of-panel 5V generation circuit (PWR 5V)  110  each supply a predetermined power supply voltage to the liquid crystal display panel  101 . 
     Further, even in the case where the image data is not inputted, the liquid crystal display panel  101  executes displaying of prewritten images by use of an image memory provided therein, as described with reference to the first embodiment. Further, the TV image display apparatus  100  incorporates a secondary battery provided separately for supplying power to drive the TV image display apparatus  100  in whole, which does not represent the essence of the invention, omitting therefore a description thereof. 
     With the present embodiment, it is possible to provide the TV image display apparatus  100  capable of effecting display at low power consumption, excellent in compactness, and design quality because of a small substrate area of the liquid crystal display panel, and further, capable of effecting high-definition display. 
     Further, with the present embodiment, for an image display device, use is made of the liquid crystal display described with reference to the first embodiment, however, needless to say, it is possible to use a display panel having a structure other than that without departing from the scope and spirit of the invention.