JP4655800B2 - Electro-optical device and electronic apparatus - Google Patents

Description

  The present invention relates to the behavior of various driven elements such as organic light emitting diode (hereinafter referred to as “OLED (Organic Light Emitting Diode)”) elements, liquid crystal elements, electrophoretic elements, electrochromic elements, electron emitting elements, and resistive elements. It is related with the technology to control.

Various methods for driving this type of driven element have been proposed. For example, Patent Document 1 discloses a configuration that displays multiple gradations by controlling the pulse width of a drive signal (for example, a current signal) supplied to an OLED element of each pixel. In this configuration, the pulse width of the drive signal is different for each pixel in accordance with the result of comparison between a data signal designating the gradation of each pixel and a signal whose level changes with time such as a triangular wave (hereinafter referred to as “reference signal”). Controlled.
JP 2003-223137 (paragraph 0014 and FIG. 2)

  By the way, in the configuration disclosed in Patent Document 1, one frame is divided into a scanning period and a light emitting period, and a data signal is supplied to all pixels in the scanning period, and then a reference signal is supplied in the light emitting period. As a result, the OLED elements of all the pixels are driven all at once (see particularly FIG. 2 of Patent Document 1). Thus, in the configuration in which the scanning period and the light emission period are separately set within one frame, for example, there is a problem that it is difficult to ensure a sufficient length of the light emission period. If the time length of the light emission period is insufficient, the brightness of each OLED element may be insufficient and the display may become dark. Furthermore, if the time length of the light emission period is short, the pulse width of the drive signal (especially the pulse width corresponding to low luminance) must be shortened. However, characteristics of an electro-optical element such as an OLED element may be deteriorated due to current concentration (for example, supply of spike-like current) in a short period.

  In the configuration of Patent Document 1, a data signal is supplied to one electrode of the capacitor. In this configuration, it may take time to accurately set the potential of the other electrode of the capacitive element when the data signal is supplied. The present invention has been made in view of the circumstances described above.

The electro-optical device according to the present invention includes a plurality of scanning lines extending in a first direction, a plurality of data lines extending in a second direction intersecting the first direction, the plurality of scanning lines, and the plurality of scanning lines. A plurality of unit circuits arranged corresponding to intersections with the data lines; a plurality of reference signal lines extending in the first direction in pairs with each of the plurality of scanning lines; and the plurality of scanning lines. A scanning line driving circuit that sequentially selects each of the plurality of data lines in each first period, a data line driving circuit that supplies a data potential to each of the plurality of data lines in each first period, and a plurality of reference signal lines Each of the plurality of unit circuits is connected to an electro-optic element driven by a drive current, an input terminal, and the electro-optic element. And the output terminal has a predetermined potential. An inverter that outputs the drive current from the output end to the electro-optic element when rotating, and stops outputting the drive current when the potential of the input end exceeds the predetermined potential, and corresponds to the unit circuit A switching element that electrically connects an input terminal of the inverter and the data line corresponding to the unit circuit in a first period in which the scanning line is selected; a first electrode connected to the input terminal; and the unit A capacitive element having a second electrode connected to the reference signal line corresponding to the circuit, wherein the signal generation circuit uses the reference signal potential to be output to each of the plurality of reference signal lines as the reference signal. For each reference signal, the scanning lines corresponding to the lines are maintained at a constant potential in a first period in which the scanning lines are selected, and sequentially arrive in the order of selection of the scanning lines corresponding to the reference signal lines. Over time changing the different second period set in position on between axis. The electro-optical element is an element (for example, a light-emitting element such as an OLED element) whose optical properties such as luminance and transmittance are changed by supplying a driving current.

In this configuration, when the data potential is supplied to the input terminal of the inverter via the switching element in the first period, and the potential of the reference signal changes with time in the second period after the first period, the capacitive element Due to the capacitive coupling, the potential at the input terminal changes from the data potential in the first period immediately before it by the variation in the potential of the reference signal. Therefore, the electro-optical element is driven in a state corresponding to the data potential by supplying the driving current in a period corresponding to the potential of the input terminal .
Here, the second period in which the potential of the reference signal changes with time is set individually for each reference signal line, and the timings are different from each other. Therefore, when the data potential of one unit circuit is captured in the first period, the electro-optic elements of the one unit circuit are sequentially driven without waiting for the data potential to be captured by other unit circuits. For example, the electro-optic elements are driven in order from the unit circuit that has completed capturing the data potential. Therefore, according to the present invention, as compared with the conventional configuration in which the period for taking in the data potential in all the unit circuits and the period for causing all the OLED elements to emit light at the same time are set separately, A sufficient period for driving the electro-optic element can be secured.

The potential of the reference signal line is set to the first potential in the first period, is the first potential at the start of the second period, becomes a second potential having a voltage level different from the first potential in the second period, It becomes the first potential at the end of the second period. More specifically, the change in the potential of the reference signal line within the second period is axisymmetric with respect to the point when the second potential is reached. That is, the reference signal has a waveform (typically a triangular wave) that is line-symmetric with respect to the midpoint (for example, the midpoint tc in FIGS. 2 and 4) between the start point and the end point of the second period.
According to this aspect, the center of gravity on the time axis of the period during which the electro-optical element is actually driven (for example, the period during which the electro-optical element emits light) can be set as the midpoint of the second period regardless of the data potential . However, the mode of change in the potential of the reference signal line (reference signal waveform) need not be strictly line symmetric .

In yet another embodiment, each of the plurality of unit circuits, the reset means (e.g. Figure 5 prior to the first period in which the scanning line corresponding to the unit circuit is selected to set the input terminal of the inverter to a predetermined potential Transistor 37). According to this aspect, since the input terminal is initialized to a predetermined potential prior to the first period, the potential of the input terminal can be set to the data potential quickly and reliably in the first period.

The electro-optical device according to each aspect described above is used in various electronic apparatuses. A typical example of this electronic apparatus is an apparatus using an electro-optical device as a display device. Examples of this type of electronic device include a personal computer and a mobile phone. However, the use of the electro-optical device according to the present invention is not limited to image display. For example, the electro-optical device of the present invention can also be applied as an exposure device (exposure head) for forming a latent image on an image carrier such as a photosensitive drum by irradiation of light.

<A: First Embodiment>
FIG. 1 is a block diagram showing a configuration of an electronic device according to the first embodiment of the present invention. The electronic device D illustrated in the figure is an electro-optical device employed in various electronic devices as means for displaying an image, and includes an element array unit 10 in which a plurality of unit circuits U are arranged in a planar shape. And a circuit for driving each unit circuit U (a scanning line driving circuit 23, a data line driving circuit 25, and a signal generation circuit 27). Note that the scanning line driving circuit 23, the data line driving circuit 25, and the signal generation circuit 27 may be mounted on the electronic device D as independent circuits, or a part or all of these circuits may be a single unit. The electronic device D may be mounted as a circuit.

  As shown in FIG. 1, the element array section 10 includes m scanning lines 13 extending in the X direction and m reference signal lines 17 extending in the X direction in pairs with the scanning lines 13. And n data lines 15 extending in the Y direction orthogonal to the X direction are formed (m and n are both natural numbers). Each unit circuit U is arranged at a position corresponding to the intersection of the pair of scanning line 13 and reference signal line 17 and data line 15. Accordingly, these unit circuits U are arranged in a matrix of m rows × n columns.

  The scanning line driving circuit 23 is a circuit for selecting each of the m scanning lines 13 in order. More specifically, as shown in FIG. 2, the scanning line driving circuit 23 has a predetermined period (hereinafter referred to as “first period”) Pa [1] to Pa [m] set for each frame (1F). The scanning signals Y [1] to Y [m] that sequentially become high level are generated and output to the scanning lines 13, respectively. The scanning signal Y [i] supplied to the scanning line 13 in the i-th row (i is an integer satisfying 1 ≦ i ≦ m) is the i-th first period Pa [i] in one frame (1F). It is a signal that becomes a high level at, and maintains a low level during other periods. The transition of the scanning signal Y [i] to the high level means selection of the i-th row.

  The data line driving circuit 25 shown in FIG. 1 sends a data signal X [1 to each row (n) of unit circuits U corresponding to the scanning line 13 selected by the scanning line driving circuit 23 via each data line 15. ] To X [n]. The data signal X [j] supplied to the data line 15 in the j-th column (j is an integer satisfying 1 ≦ j ≦ n) in the first period Pa [i] in which the i-th scanning line 13 is selected. Is the potential Vdata corresponding to the gradation (luminance) specified for the unit circuit U in the j-th column belonging to the i-th row. The gradation of each unit circuit U is specified by gradation data supplied from the outside.

  The signal generation circuit 27 is a circuit that generates reference signals W [1] to W [m] and outputs them to each of the m reference signal lines 17. As shown in FIG. 2, the reference signal W [i] maintains the potential VH from the start point to the end point of the first period Pa [i] in which the scanning signal Y [i] is at the high level, and this first period Pa [ i] is a signal whose potential varies over time from the start point to the end point of a predetermined period (hereinafter referred to as “second period”) Pb [i].

  The reference signal W [i] in the present embodiment has a waveform from the midpoint tc of the second period Pb [i] (that is, a time point having the same time length from both the start point and the end point of the second period Pb [i]) to the start point. The waveform from the midpoint tc to the end point is a triangular wave that is line symmetric with respect to the midpoint tc. That is, the reference signal W [i] decreases from the potential VH to a potential VL lower than the potential VH from the start point of the second period Pb [i] to the midpoint tc of the second period Pb [i]. From the middle point tc to the end point, the potential increases from the potential VL with the passage of time and reaches the potential VH.

  As shown in FIG. 2, the reference signals W [1] to W [m] have different phases. That is, the timing of each of the second periods Pb [1] to Pb [m] in which the reference signals W [1] to W [m] vary is set individually for each reference signal line 17 (each row) and is different from each other. To do. More specifically, each of the second periods Pb [1] to Pb [m] defined by the reference signals W [1] to W [m] supplied to each reference signal line 17 is related to the reference signal line. Each of the scanning signals Y [1] to Y [m] corresponding to 17 sequentially arrives in the order of the high level. Therefore, as shown in FIG. 2, the reference signal W [i] varies within the range from the potential VH to the potential VL in parallel with the transition of the scanning signal Y [i + 1] of the next row to the high level. .

  Next, a specific configuration of each unit circuit U will be described with reference to FIG. In the figure, only one unit circuit U located in the i-th row and j-th column is shown, but the other unit circuits U have the same configuration.

  As shown in FIG. 3, the unit circuit U includes a transistor 31, a capacitive element 33, an inverter 34, and an electro-optic element 35. The electro-optical element 35 is an OLED element in which a light emitting layer made of an organic EL material is interposed between an anode and a cathode, and emits light at a luminance level corresponding to the current level of the drive current Sdr output from the inverter 34. Note that the integrated value of the luminance level over time corresponds to the luminance.

  The inverter 34 includes a p-channel transistor 341 and an n-channel transistor 342. The source of the transistor 341 is connected to a power supply line to which a higher power supply potential Vdd is supplied. The source of the n-channel transistor 342 is connected to a ground line to which a lower power supply potential (hereinafter referred to as “ground potential”) Vss is supplied. The drains of the transistors 341 and 342 are connected in common to the anode of the electro-optic element 35. Further, the gates of the transistors 341 and 342 are connected to each other at the input terminal T.

  When the potential Va at the input terminal T of the inverter 34 is lower than a predetermined potential (hereinafter simply referred to as “threshold voltage”) Vth, the transistor 341 is turned on and the drive current Sdr is supplied to the electro-optical element 35. . This drive current Sdr is a current that causes the electro-optic element 35 to emit light. On the other hand, when the potential Va exceeds the threshold voltage Vth, the transistor 341 is turned off and the transistor 342 is turned on, so that the supply of the drive current Sdr to the electro-optic element 35 is stopped.

  3 includes a first electrode E1 connected to the input terminal T of the inverter 34 and a second electrode E2 connected to the reference signal line 17, and includes a first electrode E1 and a second electrode E2. Accumulate charges in between. The n-channel transistor 31 is a switching element that is interposed between the input terminal T of the inverter 34 and the data line 15 and controls electrical connection (conduction and non-conduction) between the two. The gate of the transistor 31 is connected to the scanning line 13. Accordingly, the transistor 31 is turned on in the first period Pa [i] in which the scanning signal Y [i] is at the high level, and the transistor 31 is turned off in the period in which the scanning signal Y [i] is kept at the low level.

  Next, a specific operation of the electronic device D according to the present embodiment will be described. Hereinafter, the operation of the unit circuit U in the j-th column belonging to the i-th row will be described by dividing it into a first period Pa [i] and a second period Pb [i].

(a) First period Pa [i]
In the first period Pa [i], the scanning signal Y [i] transitions to a high level, so that the transistor 31 is turned on and the input terminal T and the data line 15 are electrically connected. As a result, the potential Vdata of the data signal X [j] is supplied from the data line 15 to the input terminal T of the inverter 34, and the charge corresponding to the potential Vdata is held in the capacitive element 33. As shown in FIG. 2, the reference signal W [i] supplied to the second electrode E2 of the capacitive element 33 maintains a constant potential (potential VH) in the first period Pa [i]. Va is held at the potential Vdata corresponding to the gradation of the unit circuit U.

(b) Second period Pb [i]
When the first period Pa [i] elapses and the scanning signal Y [i] becomes low level, the transistor 31 shifts to the off state. Therefore, the input terminal T is electrically disconnected from the data line 15 and becomes the floating state. . This state is also maintained in the second period Pb [i]. Therefore, when the reference signal W [i] supplied to the second electrode E2 of the capacitive element 33 varies within the range from the potential VH to the potential VL in the second period Pb [i], capacitive coupling in the capacitive element 33 is performed. Thus, the potential Va (the potential of the first electrode E1) at the input terminal T varies from the potential Vdata set in the immediately preceding first period Pa [i] by the change in the reference signal W [i].

  FIG. 4 is a timing chart showing the relationship between the potential Va at the input terminal T and the drive current Sdr output from the inverter 34. In the figure, the waveform of the potential Va when each gradation (G0 to G3) is designated in the unit circuit U is also shown. Further, the potential V0 to potential V3 in the figure is the potential Vdata of the data signal X [j] when each of the gradations G0 to G3 is designated (that is, the potential Va set in the first period Pa [i]). It is.

  As shown in FIG. 4, the potential Va at the input terminal T changes by ΔV (= VH−VL) in accordance with the fluctuation of the reference signal W [i] in the second period Pb [i]. Since the potential Va is set to the potential Vdata corresponding to the gradation at the start point of the second period Pb [i], the potential Va at the input terminal T in the second period Pb [i] sets the threshold voltage Vth of the inverter 34. The period below (hereinafter referred to as “driving period”) has a time length corresponding to the potential Vdata supplied from the data line 15 in the immediately preceding first period Pa [i]. For example, since the potential Vdata (V1) corresponding to the gradation G1 is higher than the potential Vdata (V2) corresponding to the gradation G2, the time when the potential Va falls below the threshold voltage Vth when the gradation G2 is designated. The length is longer than the time length during which the potential Va falls below the threshold voltage Vth when the gradation G1 is designated. When the gradation G0 is designated, the potential Va exceeds the threshold voltage Vth over the entire period of the second period Pb [i].

  Since the potential Va at the input terminal T varies as described above, the drive current Sdr is supplied from the inverter 34 to the electro-optic element 35 in the drive period of the time length (pulse width) corresponding to the data signal X [j]. During the remaining period, the supply of the drive current Sdr to the electro-optic element 35 is stopped. For example, as shown in FIG. 4, during the drive period in which the drive current Sdr is supplied to the electro-optic element 35 when the gradation G2 is designated, the drive current Sdr is supplied when the gradation G1 is designated. Longer than the driving period. When the gradation G0 is designated, the supply of the drive current Sdr to the electro-optic element 35 is stopped over the entire period of the second period Pb [i]. Since the electro-optical element 35 emits light when the drive current Sdr is supplied, in this embodiment, the electro-optical element 35 emits light at a time density corresponding to the potential Vdata of the data signal X [j]. As a result, the gradation of the electro-optic element 35 is controlled for each unit circuit U.

  Although the operation of one unit circuit U has been described above, the same operation is executed in each unit circuit U in units of rows. More specifically, as shown in FIG. 2, the supply of the potential Vdata to the input terminal T (first period Pa [i]) and the fluctuation of the potential Va according to the reference signal W [i] (second period Pb). [i]) are sequentially performed for each unit circuit U in each row at separate timings. Therefore, when the data signal X [j] is taken into one unit circuit U in the first period Pa [i] (that is, when the potential Vdata is supplied to the input terminal T), the data for the other unit circuits U is stored. The electro-optic elements 35 are sequentially driven without waiting for the capture of the signal X [j]. In other words, the electro-optic element 35 emits light in order from the unit circuit U that has completed taking in the data signal X [j].

  As described above, according to the present embodiment, since the electro-optical element 35 is binary driven by supplying and stopping the drive current Sdr, the current supplied to the electro-optical element 35 (or electro-optical). Compared with a configuration in which the voltage applied to the element 35 is controlled stepwise corresponding to each gradation, the influence of variations in the characteristics of the transistors constituting the electro-optic element 35 and the inverter 34 can be reduced. Furthermore, in this embodiment, since the potential of the second electrode E2 of the capacitive element 33 is set directly by the reference signal line 17, it is possible to set the potential of each electrode of the capacitive element 33 in a short time. is there.

  Moreover, according to the present embodiment, compared to the conventional configuration in which the scanning period for supplying data signals to all unit circuits and the light emission period for simultaneously emitting light to all OLED elements are set separately, A period during which each electro-optic element 35 emits light can be secured for a long time. Accordingly, each electro-optical element 35 can emit light with sufficient luminance. In addition, since the pulse width of the drive current Sdr can be set longer than in the conventional configuration, instantaneous current concentration on the electro-optic element 35 (spike-like current supply) can be avoided and the characteristics of the electro-optic element 35 can be avoided. It becomes possible to suppress degradation of the.

<B: Second Embodiment>
Next, a second embodiment of the present invention will be described. In addition, about the element similar to 1st Embodiment among this embodiment, a common code | symbol is attached | subjected and each detailed description is abbreviate | omitted suitably.

  FIG. 5 is a circuit diagram showing a configuration of one unit circuit U of the electronic device D according to the present embodiment. As shown in the figure, the unit circuit U of the present embodiment has a configuration in which an n-channel transistor 37 is added to the configuration of the first embodiment illustrated in FIG. The transistor 37 is a switching element that is interposed between the input terminal T and the output terminal of the inverter 34 and controls the electrical connection (conduction and non-conduction) between the two.

  The gate of the transistor 37 is connected to a wiring to which a reset signal R [i] is supplied. The reset signal R [i] is a signal that becomes high level in the period before the start of the first period Pa [i] in which the scanning signal Y [i] becomes high level and maintains the low level in other periods. . That is, the reset signal R [1] to the reset signal R [m] are sequentially set to the high level in the order in which each row is selected.

  In the above configuration, when the reset signal R [i] becomes high level, the transistor 37 is turned on, and the input terminal T and the output terminal of the inverter 34 are electrically connected. Accordingly, the potentials at both the input terminal T and the output terminal of the inverter 34 converge to the difference value (Vdd−Vth_P) between the power supply potential Vdd and the threshold voltage Vth_P of the p-channel transistor 341. In this way, by setting the potential Va of the input terminal T to a predetermined value prior to the first period Pa [i], the potential Va of the input terminal T is quickly and reliably set to the potential Vdata in the first period Pa [i]. There is an advantage that it can be set. In addition, since the potential between the electro-optic element 35 and the output terminal of the inverter 34 is initialized to a predetermined value, the time required for the response of the electro-optic element 35 can be made uniform over a plurality of unit circuits U.

<C: Modification>
Various modifications can be made to each of the above embodiments. An example of a specific modification is as follows. In addition, you may combine each following aspect suitably.

(1) Modification 1
In each embodiment, the reference signal W [i] in the second period Pb [i] is exemplified as a triangular wave. However, the waveform of the reference signal W [i] in the second period Pb [i] is appropriately changed. Is done. For example, in each embodiment, the reference signal W [i] whose waveform is line symmetric with respect to the midpoint tc of the second period Pb [i] is illustrated, but in the present invention, the symmetry of the reference signal W [i] Is not required. For example, various waveforms such as a ramp wave, a sawtooth wave (sawtooth wave), and a multi-ramp wave (step wave) are applied to the reference signal W [i] in the second period Pb [i]. Further, not only a waveform in which the potential changes linearly but also a waveform that changes in a curve such as a sine wave may be applied to the reference signal W [i] in the second period Pb [i].

  Further, in each embodiment, the reference signal W [i] is exemplified to have a waveform of one period of the triangular wave in the second period Pb [i]. However, the reference signal W [i] has various waveforms such as the triangular wave and the ramp wave and sawtooth wave exemplified above. A reference signal is a waveform in which a plurality of unit waveforms are continued in the second period Pb [i] (that is, a waveform in which a plurality of unit waveforms are arranged on the time axis so as to repeat the increase and decrease of the potential multiple times). You may apply to W [i]. As described above, in the present invention, the reference signal W [i] whose potential varies with the passage of time in the second period Pb [i] is appropriately set according to the driving mode, function, etc. of the electro-optic element 35. It is possible to select.

  Furthermore, in each embodiment, the configuration in which the potential Va of the input terminal T starts to fluctuate from the potential Vdata in the first period Pa [i] when the second period Pb [i] starts is illustrated, but the second period Pb [i] The waveform of the reference signal W [i] may be selected so that the potential Va of the input terminal T varies at the start point and the end point of i]. For example, the reference signal W [i] illustrated in FIG. 6 may be used. The reference signal W [i] in the figure rises in potential by the change amount Vd at the start point of the second period Pb [i] and decreases in potential by the change amount Vd at the end point of the second period Pb [i]. In addition, as in the first embodiment, the potential drops and rises within the range of the voltage ΔV from the start point to the end point of the second period Pb [i]. The potential Va at the input terminal T varies according to the waveform of the reference signal W [i]. That is, as shown in FIG. 6, the potential Va first rises from the potential Vdata by the amount of change Vd at the start point of the second period Pb [i], and secondly, the interval from the start point to the midpoint tc. At the end of the second period Pb [i], and drops to Vdata at the end of the second period Pb [i]. Also in this configuration, the drive current Sdr is output from the inverter 34 over a time length corresponding to the data signal X [j], as in each embodiment.

(2) Modification 2
The specific configuration of the unit circuit U is not limited to the example shown in FIG. For example, the conductivity type of each transistor is arbitrarily changed from the example of FIG. In each of the embodiments, the configuration in which the output terminal of the inverter 34 and the anode of the electro-optic element 35 are directly connected is illustrated. However, as shown in FIG. For example, 39 gates may be connected. The transistor 39 is a means for generating a drive current Sdr, and is interposed between a power supply line to which the power supply potential Vdd is supplied and the anode of the electro-optic element 35. When the transistor 341 is turned on and the power supply potential Vdd is output from the inverter 34, the transistor 39 is turned on. At this time, the drive current Sdr flows through the electro-optic element 35 to emit light. On the other hand, when the ground potential Vss is output from the inverter 34, the transistor 39 is turned off, so that the supply of current is stopped and the electro-optic element 35 is turned off. Also with this configuration, the same operations and effects as those of the embodiments are achieved.

  Further, the means for outputting the drive current Sdr (drive means in the present invention) is not limited to the inverter 34. For example, instead of the inverter 34 of FIGS. 3, 5, and 7, a comparator that compares the potential Va of the input terminal T with a predetermined potential and outputs a drive current Sdr according to the result may be installed. . For example, the comparator outputs the power supply potential Vdd when the potential Va is lower than a predetermined potential, and outputs the ground potential Vss when the potential Va is higher than the predetermined potential. Also with this configuration, the same operations and effects as those of the embodiments are achieved. Further, the signal supplied to the electro-optical element 35 may be a current signal (the drive current Sdr illustrated in each embodiment) or a voltage signal. As described above, the driving means in the present invention is a drive signal (the drive current Sdr or the drive) according to the potential Va of the input terminal T (more specifically, according to the magnitude of the potential Va and the predetermined potential). Any element that outputs (voltage) is sufficient, and its specific configuration is not questioned.

(3) Modification 3
In each embodiment, the configuration in which the reference signal line 17 is formed so as to correspond to each of the plurality of scanning lines 13 (that is, for each row) is illustrated, but the correspondence between the scanning line 13 and the reference signal line 17 is illustrated. The relationship is not limited to this. For example, the reference signal line 17 is formed so as to correspond to each of the groups obtained by dividing the m scanning lines 13 into predetermined lines, and each reference signal line 17 is connected to each unit circuit U belonging to one group. It is good also as a structure. In this configuration, the capturing of the data signal X [j] is executed for each row, while the driving of the electro-optic element 35 due to the variation of the reference signal W [i] is executed for each group.

(4) Modification 4
In the second embodiment, the configuration in which the input terminal T of the inverter 34 is electrically connected to the output terminal prior to the first period Pa [i] is illustrated, but the connection destination of the input terminal T of the inverter 34 is appropriately set. Changed to For example, the transistor 37 is interposed between the wiring maintained at a predetermined potential and the input terminal T of the inverter 34, and the inverter 37 is turned on prior to the first period Pa [i]. The configuration may be such that the input terminal T of 34 is initialized to a predetermined potential.

(5) Modification 5
In the above embodiment, an OLED element is exemplified as the electro-optical element 35, but the electro-optical element employed in the electronic apparatus of the present invention is not limited to this. For example, instead of an OLED element, an inorganic EL element, a field emission (FE) element, a surface-conduction electron (SE) element, a ballistic electron surface emitting (BS) element, Various self-luminous elements such as LED (Light Emitting Diode) elements, and various electro-optical elements such as electrophoretic elements and electrochromic elements can be used. The present invention is also applied to a sensing device such as a biochip. The driven element of the present invention is a concept including all elements driven by application of electric energy, and an electro-optical element such as a light emitting element is merely an example of the driven element.

<D: Application example>
Next, an electronic apparatus using the electronic apparatus (electro-optical apparatus) according to the present invention will be described. FIG. 8 is a perspective view showing the configuration of a mobile personal computer that employs the electronic device D according to any one of the embodiments described above as a display device. The personal computer 2000 includes an electronic device D as a display device and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002. Since this electronic device D uses an OLED element as the electro-optic element 35, it is possible to display a screen having a wide viewing angle and easy to see.

  FIG. 9 shows a configuration of a mobile phone to which the electronic device D according to the embodiment is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and an electronic device D as a display device. By operating the scroll button 3002, the screen displayed on the electronic device D is scrolled.

  FIG. 10 shows a configuration of a personal digital assistant (PDA) to which the electronic device D according to the embodiment is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and an electronic device D as a display device. When the power switch 4002 is operated, various kinds of information such as an address book and a schedule book are displayed on the electronic device D.

  The electronic apparatus to which the electronic apparatus (electro-optical apparatus) according to the present invention is applied includes the digital still camera, television, video camera, car navigation apparatus, pager, and electronic notebook in addition to those shown in FIGS. Electronic paper, calculator, word processor, workstation, video phone, POS terminal, printer, scanner, copier, video player, equipment equipped with a touch panel, and the like. Further, the use of the electronic device according to the present invention is not limited to the display of images. For example, in an image forming apparatus such as an optical writing type printer or an electronic copying machine, a writing head that exposes a photosensitive member according to an image to be formed on a recording material such as paper is used. However, the electronic device of the present invention is used. The unit circuit referred to in the present invention is a concept including not only a circuit constituting a pixel of a display device (a so-called pixel circuit) but also a circuit as a unit of exposure in the image forming apparatus.

1 is a block diagram illustrating a configuration of an electronic device according to a first embodiment of the present invention. 6 is a timing chart showing waveforms of a scanning signal Y [i] and a reference signal W [i]. It is a circuit diagram which shows the structure of one unit circuit. 6 is a timing chart showing a relationship between a potential Va and a drive current Sdr. It is a circuit diagram which shows the structure of one unit circuit in the electronic device of 2nd Embodiment of this invention. It is a timing chart which shows the waveform of reference signal W [i] concerning a modification. It is a circuit diagram which shows the structure of the unit circuit which concerns on a modification. It is a perspective view which shows the specific form of the electronic device which concerns on this invention. It is a perspective view which shows the specific form of the electronic device which concerns on this invention. It is a perspective view which shows the specific form of the electronic device which concerns on this invention.

Explanation of symbols

D: Electronic device, 10: Element array section, 13: Scan line, 15: Data line, 17: Reference signal line, 23: Scan line drive circuit, 25: Data line drive circuit, 27 ... ... Signal generation circuit, 37 ... transistor, 33 ... capacitance element, 34 ... inverter, T ... input terminal of inverter, 35 ... electro-optic element, Y [i] ... scanning signal, X [j] ... ... data signal, Vdata ... potential of data signal, W [i] ... reference signal, Sdr ... drive current, Va ... potential of input terminal of inverter.

Claims (3)

A plurality of scanning lines extending in a first direction ;
A plurality of data lines extending in a second direction intersecting the first direction ;
A plurality of unit circuits arranged corresponding to intersections of the plurality of scanning lines and the plurality of data lines;
A plurality of reference signal lines extending in the first direction in pairs with each of the plurality of scanning lines ;
A scanning line driving circuit for sequentially selecting each of the plurality of scanning lines for each first period;
A data line driving circuit for supplying a data potential to each of the plurality of data lines in each of the first periods;
A signal generation circuit that outputs different reference signals to each of the plurality of reference signal lines ,
Each of the plurality of unit circuits is
An electro-optical element driven by supplying a driving current;
An input end and an output end connected to the electro-optic element, and when the potential of the input end is lower than a predetermined potential, the drive current is output from the output end to the electro-optic element, An inverter that stops the output of the drive current when the potential exceeds the predetermined potential;
A switching element that electrically connects an input terminal of the inverter and the data line corresponding to the unit circuit in a first period in which the scanning line corresponding to the unit circuit is selected ;
A capacitive element having a first electrode connected to the input terminal and a second electrode connected to the reference signal line corresponding to the unit circuit ;
The signal generation circuit outputs a reference signal potential to be output to each of the plurality of reference signal lines.
Maintaining a constant potential in a first period in which the scanning line corresponding to the reference signal line is selected;
An electro-optical device that changes over time in a second period set at different positions on the time axis for each of the reference signals so that the scanning lines corresponding to the reference signal lines sequentially arrive in the order of selection. . Each of the plurality of unit circuits includes reset means for setting the input terminal of the inverter to a predetermined potential prior to a first period in which the scanning line corresponding to the unit circuit is selected.
The electro-optical device according to claim 1. An electronic apparatus comprising the electro-optical device according to claim 1 .

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