JP4266682B2 - Electronic device, driving method of electronic device, electro-optical device, and electronic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic circuit, an electronic apparatus, an electronic circuit driving method, an electro-optical apparatus, and an electronic apparatus.
[0002]
[Prior art]
In recent years, electro-optical devices using organic EL elements have attracted attention as display devices as electro-optical devices. An electro-optical device using this type of organic EL element includes an active matrix driving method as one of driving methods.
[0003]
In an active matrix driving type electro-optical device, a pixel circuit is provided for each organic EL element in order to control the luminance of the organic EL element. The luminance gradation of the organic EL element in each pixel circuit is controlled by supplying a data signal (voltage value or current value) corresponding to the luminance gradation to the holding capacitor of the pixel circuit. That is, the storage capacitor is charged with a charge according to the set light emission luminance gradation.
Then, a conduction state of a driving TFT (ThinFilm Transistor) is set according to the amount of charge held in the holding capacitor, and a current corresponding to the conduction state is supplied to the organic EL element (see, for example, Patent Document 1). .
[0004]
[Patent Document 1]
International Publication No. WO98 / 36406 Pamphlet
[0005]
[Problems to be solved by the invention]
Incidentally, although the pixel circuit is composed of at least one active element such as a transistor, it is difficult to strictly equalize the characteristics of all the active elements. In particular, thin film transistors (TFTs) constituting pixel circuits such as displays have large variations in characteristics. For this reason, it is difficult to obtain a desired luminance when a predetermined data signal is input.
[0006]
In addition, there is a problem that the characteristics change due to the deterioration of the active elements and electro-optical elements constituting the pixel circuit over time.
[0007]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electronic circuit, an electronic device, an electronic circuit driving method, and an electro-optical device capable of detecting the operating characteristics of the electronic circuit with high accuracy. It is to provide an apparatus and an electronic device.
[0008]
[Means for Solving the Problems]
The first electronic device according to the present invention is an electronic device including a plurality of unit circuits, and each of the plurality of unit circuits includes a first transistor and an electric power supplied via the first transistor. A holding element that holds a signal as an electric quantity, a second transistor whose conduction state is controlled based on the electric quantity held in the holding element, and a driven element that is supplied with a current amount relative to the conduction state And a third transistor connected in series with the second transistor, and is connectable to an inspection unit for detecting a current amount via the third transistor.
[0009]
According to this, by turning on the third transistor, the amount of current relative to the amount of charge from the second transistor to be supplied to the driven element can be obtained via the third transistor. Therefore, the operating characteristics of the electronic circuit can be detected. Note that the third transistor may be provided in each unit circuit, or may be provided in common to several unit circuits among the plurality of unit circuits.
[0010]
A second electronic device according to the present invention is an electronic device including a plurality of unit circuits, and each of the plurality of unit circuits includes a first transistor and an electric power supplied via the first transistor. A holding element that holds a signal as an electric quantity, a second transistor whose conduction state is controlled based on the electric quantity held in the holding element, and a driven element that is supplied with a current amount relative to the conduction state The second transistor is connected in series with the first transistor, and can be connected to an inspection unit for detecting a current amount via the first transistor. And
[0011]
As a corresponding embodiment of the second electronic device, for example, an electronic device having a circuit configuration in which a current signal is supplied as an electric signal as in a fourth embodiment described later.
[0012]
In the above electronic device, a fourth transistor is connected between the driven element and the second transistor.
[0013]
According to this, the fourth transistor is turned off, the current supply to the driven element is stopped, and the third transistor or the first transistor is turned on to turn the driven transistor on. The amount of current passing through the second transistor to be supplied to the element can be detected via the third transistor or the first transistor. That is, it is preferable that the fourth transistor is at least in an off state during the period in which the inspection unit performs detection.
[0014]
In the electronic device, the driven element may be a current driving element such as an organic EL element. In the organic EL element, the light emitting layer is made of an organic material.
[0015]
In the above electronic device, it is preferable that the third transistor is provided in each of the plurality of unit circuits. This makes it possible to detect the current characteristics of each of the plurality of unit circuits.
[0016]
In the above electronic device, the holding element may be a capacitive element that holds, for example, an electric signal supplied to each of the plurality of unit circuits as a charge amount.
[0017]
In the electronic device, the holding element may be a storage element such as an SRAM.
[0018]
The electronic device includes a storage circuit that stores a correction value for the electrical signal supplied through the first transistor obtained by the inspection unit.
According to this, it is possible to adjust the operation of the driven element by correcting the operation characteristic of the electronic device using the correction value stored in the storage circuit.
[0019]
The electronic device driving method according to the present invention is based on a first transistor, a holding element that holds an electric signal supplied through the first transistor as an electric quantity, and an electric quantity held in the holding element. A second transistor whose conduction state is set, a driven element to which a current amount relative to the conduction state is supplied, and a third transistor connected in series with the second transistor. A method for driving an electronic device, comprising: a first step of turning on the first transistor to hold an electric quantity based on the electric signal in the holding element; and turning on the third transistor, And the second transistor and the third transistor are electrically connected to each other through the third transistor. Characterized by comprising a second step of detecting the amount of current passing through the current path including.
[0020]
According to this, the inspection unit can detect the amount of current to be supplied to the driven element by the inspection unit.
[0021]
In the driving method of the electronic device, it is preferable that the current path does not include the driven element.
[0022]
In the driving method of the electronic device, the driven element may be a current driving element such as an organic EL element.
[0023]
A first electro-optical device according to the present invention is an electro-optical device including a plurality of pixel circuits arranged corresponding to intersections of a plurality of scanning lines and a plurality of data lines, and the plurality of pixel circuits. Each includes a first transistor whose conduction is controlled by a scanning signal supplied via a corresponding scanning line of the plurality of scanning lines, a corresponding data line of the plurality of data lines, and the first transistor. A holding element for holding the data signal supplied via the second electric field as a quantity of electricity, a second transistor whose conduction state is controlled based on the quantity of electricity held in the holding element, and a current relative to the conduction state An electro-optic element to which a quantity is supplied, and a third transistor connected in series with the second transistor, and each of the plurality of pixel circuits supplies a current quantity via the third transistor. Characterized in that it is connectable to the inspection unit for output.
In the above electro-optical device, the third transistor may be provided in each of the plurality of pixel circuits, or may be provided in common for several pixel circuits of the plurality of pixel circuits.
In the electro-optical device, the third transistor may be connectable to the inspection unit via a corresponding data line of the plurality of transistors. According to this, the data line can be used as the inspection wiring without providing the inspection wiring.
[0024]
A second electro-optical device according to the present invention is an electro-optical device including a plurality of pixel circuits arranged corresponding to intersections of a plurality of scanning lines and a plurality of data lines, and the plurality of pixel circuits. Each includes a first transistor whose conduction is controlled by a scanning signal supplied via a corresponding scanning line of the plurality of scanning lines, a corresponding data line of the plurality of data lines, and the first transistor. A holding element that holds the data signal supplied through the first and second terminals as a quantity of electricity, and a conduction state is controlled based on the quantity of electricity held in the holding element, and the second transistor is connected in series with the first transistor. Each of the plurality of pixel circuits can be connected to an inspection unit that detects the amount of current via the first transistor. In It is characterized in.
[0025]
In the electro-optical device, the inspection unit includes a current detection circuit that detects the amount of current, a correction value calculation circuit that calculates a correction value for the electric signal based on the amount of current detected by the current detection circuit, The storage circuit stores the correction value for the pixel circuit, and the electric signal is corrected with the correction value when the electric signal is set.
[0026]
According to this, the correction value calculation circuit obtains a correction value for adjusting the variation in the operation characteristics of the pixel circuit, and the correction value for the pixel circuit is stored in the storage circuit. Therefore, the operation characteristics of the driven element can be adjusted by correcting the operation characteristics of the pixel circuit using the correction value of the electronic circuit stored in the memory circuit.
[0027]
The above-described electro-optical device is mounted on the electronic apparatus according to the invention.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0029]
FIG. 1 is a block circuit diagram showing a circuit configuration of an organic EL display 10 as an electro-optical device. FIG. 2 is a block circuit diagram showing the internal circuit configuration of the display panel unit and the data line driving circuit. FIG. 3 is a circuit diagram showing the internal circuit configuration of the pixel circuit.
[0030]
In FIG. 1, the organic EL display 10 includes a display panel unit 11, a data line driving circuit 12, a scanning line driving circuit 13, a memory 14, an oscillation circuit 15, a selection circuit 16, and a control circuit 17.
[0031]
Each element 11 to 17 of the organic EL display 10 may be constituted by independent electronic components. For example, each of the elements 12 to 17 may be configured by a one-chip semiconductor integrated circuit device. Moreover, you may be comprised as an electronic component in which all or one part of each element 11-17 was united. For example, the data line driving circuit 12 and the scanning line driving circuit 13 may be integrally formed on the display panel unit 11. All or a part of each of the constituent elements 12 to 16 may be configured by a programmable IC chip, and the function may be realized by software by a program written in the IC chip.
[0032]
As shown in FIG. 2, the display panel unit 11 has a plurality of pixel circuits 20 arranged in a matrix. That is, each pixel circuit 20 is between a plurality of data lines X1 to Xm (m is an integer) extending along the column direction and a plurality of scanning lines Y1 to Yn (n is an integer) extending along the row direction. Each pixel circuit 20 is arranged in a matrix. Each pixel circuit 20 has an organic EL element 21 having a light emitting layer made of an organic material as a driven element. A transistor described later formed in the pixel circuit 20 may be a silicon-based transistor, but in the present embodiment, it is configured by a thin film transistor (TFT).
[0033]
In the data line driving circuit 12, a data voltage generation circuit 12a is provided for each of the data lines X1 to Xm. Each data voltage generation circuit 12a supplies an electrical signal, that is, a data signal (data voltage Vdata) in this embodiment to the pixel circuit 20 via the corresponding data lines X1 to Xm. When the internal state of the pixel circuit 20 is set according to the data voltage Vdata, the pixel circuit 20 controls the current value flowing through the organic EL element 21 according to this, and the luminance of the organic EL element 21 is controlled. Is done.
[0034]
The scanning line driving circuit 13 selects and drives one of the plurality of scanning lines Yn to select a pixel circuit group for one row. Each of the scanning lines Y1 to Yn is composed of a first sub scanning line Va and a second sub scanning line Vb. The scanning line driving circuit 13 outputs the first selection signal SL1 to the first sub-scanning line Va, and outputs the second selection signal SL2 to the second sub-scanning line Vb. The memory 14 stores display data supplied from the computer 18. The memory 14 stores test display data supplied from the inspection device 19 constituting the correction value calculation circuit. The oscillation circuit 15 supplies the reference operation signal to other components of the organic EL display 10.
[0035]
The select circuit 16 is provided between the display panel unit 11 and the data line driving circuit 12. Each select circuit 16 includes a switching circuit 16a for each of the data lines X1 to Xm. Each switching circuit 16a includes a first gate transistor Q1 and a second gate transistor Q2 as shown in FIG. The first gate transistor Q1 of each select circuit 16 connects the corresponding data lines X1 to Xm to the corresponding data voltage generation circuit 30. The second gate transistor Q2 of each select circuit 16 includes a corresponding data line X1 to Xm and a current detection circuit 19a provided for each corresponding data line X1 to Xm provided in the inspection device 19 as an inspection unit. Connecting. The first and second gate transistors Q1, Q2 are on / off controlled based on the first and second gate signals G1, G2 from the control circuit 17, respectively.
[0036]
The control circuit 17 performs overall control of the elements 11 to 16. The control circuit 17 converts display data (image data) from the computer 18 stored in the memory 14 representing the display state of the display panel unit 11 into matrix data representing the luminance of light emitted from each organic EL element 21. The matrix data includes a scanning line driving signal for sequentially selecting a pixel circuit group for one row and a data line driving for determining the level of the data voltage Vdata for setting the luminance of the organic EL element 21 of the selected pixel circuit group. Signal. Then, the scanning line driving signal is supplied to the scanning line driving circuit 13. The data line drive signal is supplied to the data line drive circuit 12.
[0037]
The control circuit 17 is in a test mode when the organic EL display 10 uses the inspection device 19 to inspect each pixel circuit 20 of the display panel unit 11. In the test mode, the control circuit 17 uses the display data for test (image data) stored in the memory 14 from the test device 19 as matrix data (test matrix data) indicating the luminance of light emitted from each organic EL element 21. Convert to
[0038]
The test matrix data is a test scanning line drive signal for sequentially selecting a pixel circuit group for one row and a test brightness for setting the test luminance of the organic EL element 21 of the selected pixel circuit group. And a test data line driving signal for determining the level of the data voltage Vdata. The test scanning line drive signal is supplied to the scanning line drive circuit 13. The test data line drive signal is supplied to the data line drive circuit 12. In the test mode, the control circuit 17 supplies the selection circuit 16 with first and second gate signals G1 and G2 for inspecting each pixel circuit 20 of the display panel unit 11. Incidentally, in the normal mode other than the test mode, the control circuit 17 outputs only the first gate signal G1, maintains the state in which the first gate transistor Q1 is turned on and the second gate transistor Q2 is turned off.
[0039]
Next, the internal circuit configuration of the pixel circuit 20 will be described with reference to FIG. For convenience of explanation, the pixel circuit 20 arranged at the intersection of the mth data line Xm and the nth scanning line Yn and connected between the data line Xm and the scanning line Yn will be described.
[0040]
In this embodiment, the pixel circuit 20 is a voltage-driven pixel circuit, and includes an organic EL element 21 as a driven element. Driving transistor Q11 as the second transistor, switching transistor Q12 as the first transistor, light emission control transistor Q13 as the fourth transistor, detection transistor Q14 as the third transistor, holding as the holding element A capacitor C1 is provided.
[0041]
The switching transistor Q12 and the light emission control transistor Q13 are composed of N-channel TFTs. The driving transistor Q11 and the detection transistor Q14 are composed of P-channel TFTs.
[0042]
The drain of the driving transistor Q11 is connected to the anode of the organic EL element 21 via the switching transistor Q13, and the source is connected to the power supply line L1. A holding capacitor C1 is connected between the gate of the driving transistor Q11 and the power supply line L1. The gate of the driving transistor Q11 is connected to the data line Xm through the switching transistor Q12. Further, the drain of the driving transistor Q11 is connected to the data line Xm through the detection transistor Q14.
[0043]
The first sub-scanning line Va is connected to the gate of the switching transistor Q12. The source of the detection transistor Q14 is connected to the drain of Q11. The gates of the light emission control transistor Q13 and the detection transistor Q14 are both connected to the second sub-scanning line Vb.
[0044]
Next, the operation of the organic EL display 10 configured as described above will be described according to the operation of the pixel circuit 20.
(Normal mode)
First, the normal mode will be described with reference to the timing chart of each signal SL1, SL2, G1, G2 shown in FIG.
[0045]
Now, when the n-th scanning line Yn is selected and each pixel circuit 20 connected to the scanning line Yn is in a light emitting operation, the scanning line driving circuit 13 passes through the first sub-scanning line Va of the scanning line Yn. Thus, the first selection signal SL1 for turning on the switching transistor Q12 is output, and the switching transistor Q12 is turned on. At the same time, the first gate signal G1 for turning on the first gate transistor Q1 is output from the control circuit 17 to each switching circuit 16a of the select circuit 16, and the first gate transistor Q1 is turned on. At this time, the data voltage Vdata is supplied from each data voltage generation circuit 12a to the corresponding storage capacitor C1 of each pixel circuit 20 based on the switching transistor Q12 and the first gate transistor Q1 being turned on. After the elapse of time t1, the first selection signal SL1 and the first gate signal G1 that turn off the switching transistor Q12 and the first gate transistor Q1 are supplied, and the data writing period ends.
While the data voltage Vdata is supplied to the pixel circuit 20 via the switching transistor Q12 in the on state, the detection transistor Q14 and the light emission control transistor Q13 are in the off state and the on state, respectively.
During the time t1 or after the time t1, the supply of current to the organic EL element according to the conduction state of the driving transistor Q11 is started.
[0046]
Next, the light emission control transistor Q13 is turned off to stop the supply of current to the organic EL element and wait for the start of the next data writing period.
[0047]
Note that, during the period in which the data voltage Vdata is supplied to the pixel circuit 20 via the switching transistor Q12, the detection transistor Q14 may be in either an on state or an off state.
However, since a minute current flowing between the pixel circuit 20 and the data line Xm through the detection transistor Q14 in the on state may cause perturbation of the data voltage Vdata, the data voltage as in the present embodiment. During the period when Vdata is supplied to the pixel circuit 20 via the switching transistor Q12, it is preferable that the detection transistor Q14 be in an off state.
Furthermore, of course, it does not matter even if the detection transistor Q14 is in the OFF state during the entire period of the normal mode.
In the present embodiment, the light emission control transistor Q13 and the detection transistor Q14 have a circuit configuration that operates in a complementary manner, but of course, they can be controlled independently.
[0048]
By repeating this operation, the organic EL elements 21 of the pixel circuits 20 on the scanning lines Y1 to Yn are controlled to emit light with the luminance corresponding to the data voltage Vdata, and the organic EL display 10 displays the display data from the computer 18. Display the based image.
[0049]
(Test mode)
Next, a test mode that is one mode of the driving method will be described. The organic EL display 10 enters a test mode when connected to the inspection device 19. When the test display data is output from the inspection device 19 to the organic EL display 10, the control circuit 17 enters the test mode, and the test display data is converted into matrix data (test data) indicating the luminance gradation of the light emission of each organic EL element 21. Matrix data). Then, the control circuit 17 outputs the test scan line drive signal and the test data line drive signal to the scan line drive circuit 13 and the data line drive circuit 12.
[0050]
FIG. 5 is a timing chart of the signals SL1, SL2, G1, and G2 in the test mode. Now, for example, the first selection signal SL1 for turning on the switching transistor Q12 is output from the scanning line driving circuit 13 to the first sub-scanning line Va of the scanning line Yn, and the pixel circuits 20 on the scanning line Yn are output. The switching transistor Q12 is turned on. At the same time, the first gate signal G1 for turning on the first gate transistor Q1 is output from the control circuit 17 to each switching circuit 16a of the select circuit 16, and the first gate transistor Q1 of each switching circuit 16a is turned on. Become.
[0051]
As a result, the test data voltage Vdata is supplied from the data voltage generation circuit 12a to the holding capacitor C1 via the switching transistor Q12 and the first gate transistor Q1 in the on state. On the other hand, during the period in which the test data voltage Vdata is supplied, the second selection signal SL2 for turning off the detection transistor Q14 is supplied to turn off the detection transistor Q14.
After the elapse of time t1, the first selection signal SL1 and the first gate signal G1 that turn off the switching transistor Q12 and the first gate transistor Q1 are supplied, and the data writing period in the pixel circuit 20 ends. At this time, the second selection signal SL2 is supplied to turn on and off the detection transistor Q14 and the light emission control transistor Q13.
[0052]
Next, the second gate signal G2 for turning on the second gate transistor Q2 is supplied from the control circuit 17 to each switching circuit 16a of the select circuit 16, and the second gate transistor Q2 is turned on. In the pixel circuit 20, a drive current having a current value relative to the test data voltage Vdata based on the operation of the drive transistor Q11 flows when the second gate transistor Q2 is turned on. At this time, the drive current from the drive transistor Q11 is supplied to each current detection circuit provided for each pixel circuit 20 on the scanning line Yn of the inspection device 19 via the detection transistor Q14 and the second gate transistor Q2. It is output to 19a.
[0053]
Then, this operation is sequentially performed on each pixel circuit 20 of each scanning line Y1 to Yn, and output to each current detection circuit 19a provided for each pixel circuit 20 of each scanning line Y1 to Yn.
[0054]
In the inspection device 19, the current detection circuit 19a provided for each pixel circuit 20 of each scanning line Y1 to Yn digitally converts the input output current to obtain the output current value as the detected current value. Then, the inspection device 19 compares the detection current value of the pixel circuit 20 obtained by each current detection circuit 19a with the set current value for the test data voltage Vdata. Then, the inspection device 19 temporarily stores the comparison result. The set current value is a current value that must be output from the pixel circuit 20 with the test data voltage Vdata according to the standard, and is a value obtained in advance from a test or theory.
[0055]
After temporarily storing the comparison result, a similar test is performed on the organic EL display 10 using a test data voltage Vdata having a different value. In the same manner as described above, the inspection device 19 compares the detected current value of the pixel circuit 20 obtained by each current detection circuit 19a with the set current value for the test data voltage Vdata, and stores the comparison result.
[0056]
The inspection device 19 inspects the output current characteristic of the driving transistor Q11 with respect to the data voltage Vdata of each pixel circuit 20 based on the comparison result with respect to the two different types of test data voltages Vdata. Then, the inspection device 19 obtains a correction value for each pixel circuit 20 so that the characteristic of each pixel circuit 20 becomes a target (standard) characteristic. That is, a correction value ΔVd for the data voltage Vdata with respect to the set luminance is obtained for each pixel circuit 20.
[0057]
The inspection device 19 outputs the correction value ΔVd obtained for each of the obtained pixel circuits 20 to the organic EL display 10. The correction value ΔVd obtained for each pixel circuit 20 is stored in a memory 17a made of a nonvolatile memory or the like built in the control circuit 17, and the test mode ends. In this embodiment, although stored in the memory 17a, a fuse for setting a correction value may be formed, and the corresponding fuse may be cut based on the inspection result of the inspection device 19.
[0058]
The control circuit 17 uses the correction value ΔVd when converting the display data (image data) from the computer 18 into matrix data representing the gradation of light emission of each organic EL element 21. More specifically, the control circuit 17 calculates a value obtained by correcting the data voltage Vdata for setting the luminance of the organic EL element 21 of each pixel circuit 20 obtained based on the display data by the corresponding correction value ΔVd as a new data voltage Vdata. To do. The control circuit 17 outputs the new data voltage Vdata of each pixel circuit 20 to the data line driving circuit 12 as a data line driving signal.
[0059]
Therefore, it is possible to detect variations in the operation characteristics of the pixel circuits (transistors; in particular, the driving transistor Q11) due to manufacturing variations. In addition, it is possible to make the luminance with respect to the data voltage Vdata of the organic EL element 21 of each pixel circuit 20 constant by correcting variations in the operation characteristics of each pixel circuit 20.
[0060]
Further, the inspection device 19 can be used as a material for determining whether or not the product can be shipped if the pixel circuit 20 is determined to be inoperable when the detected current value is not within the reference range.
[0061]
Next, the characteristics of the organic EL display 10 configured as described above will be described below.
(1) In the present embodiment, the pixel circuit 20 is provided with the switching transistor Q13 and the detection transistor Q14. In the test mode, the drive current having the current value corresponding to the test data current Vdata from the drive transistor Q11 can be supplied to the current detection circuit 19a of the detection device 19 via the detection transistor Q14.
[0062]
Therefore, the operation characteristics of each pixel circuit 20 due to manufacturing variations can be easily detected. As a result, defective products of the organic EL display 10 can be inspected before shipment.
[0063]
(2) In the present embodiment, the correction value for correcting the error of the operation characteristic based on the manufacturing variation obtained by the inspection device 19 for each pixel circuit 20 in the memory 17a built in the control circuit 17, that is, for the set luminance The correction value ΔVd for the data voltage Vdata was stored. Then, the control circuit 17 corrects the data voltage Vdata for setting the luminance of the organic EL element 21 of each pixel circuit 20 obtained based on the display data with the corresponding correction value ΔVd.
[0064]
Accordingly, each pixel circuit 20 can supply a driving current having a uniform current value to the organic EL element 21 with respect to the data voltage Vdata based on the display data, and can emit the organic EL element with uniform luminance. . In addition, since the operation characteristics due to manufacturing variations can be corrected for each pixel circuit 20 with the correction value ΔVd, an organic EL display that has been discarded as a defective product in the past is improved as a product, so that the manufacturing yield of the organic display is improved. be able to.
[0065]
(3) In this embodiment, the drive current for detection is supplied to the current detection circuit 19a using the existing data lines X1 to Xm. Therefore, an increase in circuit scale for current detection can be suppressed.
[0066]
In the present embodiment, the driving transistor (second transistor) Q11 and the detection transistor (third transistor) Q14 are connected in series, but between the driving transistor Q11 and the detection transistor Q14. Other elements may be inserted. Also in this case, the detection transistor Q14 is connected in series with the drive transistor Q11.
[0067]
(Second Embodiment)
Next, a second embodiment will be described. In the first embodiment, the inspection device 19 is an external device, but in this embodiment, the inspection device 19 is configured as the same element as each element 11 to 17 of the organic EL display 10 of the first embodiment. It is. Therefore, the inspection device 19 is built in a portable electronic device such as a mobile phone, a PDA, or a laptop computer that mounts the organic EL display 10 together with the organic EL display 10.
[0068]
In addition, since there is only a characteristic in the point incorporated in a portable electronic device, the part which is common in 1st Embodiment is abbreviate | omitted for convenience of explanation, and the characteristic part is demonstrated.
FIG. 6 shows an electric circuit of the inspection apparatus 19 of the present embodiment.
[0069]
In FIG. 6, the current detection circuit unit 31 includes a number of current detection circuits 31a corresponding to the data lines X1 to Xm. Each current detection circuit 31a performs analog detection of the drive current for the test data voltage Vdata from the drive transistor Q11 supplied from the data lines X1 to Xm via the switching circuit 16a. Test display data is stored in advance in the memory 17 a of the control circuit 17.
[0070]
Each current detection circuit 31 a is connected to a corresponding AD converter 32 a of the AD conversion circuit unit 32. Each AD converter 32 a converts the current value of the drive current supplied from the data lines X <b> 1 to Xm into a digital value and outputs the digital value to the control circuit 17.
[0071]
The control circuit 17 compares the current value of the drive current supplied from the data lines X1 to Xm from each AD converter 32a with the set current value for the test data voltage Vdata. The control circuit 17 temporarily stores the comparison result. That is, in the present embodiment, the control circuit 17 performs the same inspection process as the inspection device 19 of the first embodiment. In the present embodiment, after each pixel circuit 20 connected on one scanning line is inspected, each pixel circuit on the next scanning line is inspected.
[0072]
After temporarily storing the comparison result, a similar test is performed on the organic EL display 10 using a test data voltage Vdata having a different value. Then, similarly to the above, the control circuit 17 compares the current value of the drive current supplied from the data lines X1 to Xm from each AD converter 32a with the set current value for the test data voltage Vdata, The comparison result is stored.
[0073]
The control circuit 17 inspects the output current characteristic of the driving transistor Q11 with respect to the data voltage Vdata of each pixel circuit 20 based on the comparison result with respect to the two different types of test data voltages Vdata. Then, the control circuit 17 obtains a correction value for each pixel circuit 20 so that the characteristic of each pixel circuit 20 becomes a target (standard) characteristic. That is, a correction value ΔVd for the data voltage Vdata with respect to the set luminance is obtained for each pixel circuit 20. The control circuit 17 stores the obtained correction value ΔVd in the memory 17a serving as a storage circuit, and the test mode ends. The control circuit 17 is configured to execute the test mode periodically or immediately after the power is turned on. The control circuit 17 uses the correction value ΔVd to drive and control each pixel circuit 20 based on the display data as in the first embodiment.
[0074]
Next, the characteristics of the organic EL display 10 configured as described above will be described below.
(1) In the present embodiment, the pixel circuit 20 is provided with the switching transistor Q13 and the detection transistor Q14. Then, in the test mode, the current value of the drive current corresponding to the test data current Vdata from the drive transistor Q11 is supplied to the control circuit 17 via the detection transistor Q14.
Then, the control circuit 17 detects the operating characteristics of each pixel circuit 20. Therefore, the operation characteristics of each pixel circuit 20 due to manufacturing variations can be easily detected without using a large inspection device. In addition, if the control circuit 17 is made to execute the test mode periodically or immediately after the power is turned on, it is possible to detect the operation characteristics of the pixel circuits 20 due to aging and environmental temperature changes.
[0075]
(2) In the present embodiment, the memory 17a built in the control circuit 17 includes an error in the operation characteristics based on the manufacturing variation, the secular change, and the environmental temperature, which is obtained by the control circuit 17 for each pixel circuit 20. A correction value to be corrected, that is, a correction value ΔVd with respect to the data voltage Vdata with respect to the set luminance was stored. Then, the control circuit 17 corrects the data voltage Vdata for setting the luminance of the organic EL element 21 of each pixel circuit 20 obtained based on the display data with the corresponding correction value ΔVd.
[0076]
Accordingly, each pixel circuit 20 can supply a driving current having a uniform current value to the organic EL element 21 with respect to the data voltage Vdata based on the display data even when the aging and the environmental temperature change. Light can be emitted with uniform brightness.
[0077]
(3) In this embodiment, the drive current for detection is supplied to the current detection circuit 19a using the existing data lines X1 to Xm. Therefore, an increase in circuit scale for current detection can be suppressed.
[0078]
(Third embodiment)
Next, application of the electronic apparatus of the organic EL display 10 as the electro-optical device described in the first and second embodiments will be described with reference to FIGS. The organic EL display 10 can be applied to various electronic devices such as a mobile personal computer, a mobile phone, and a digital camera.
[0079]
FIG. 7 is a perspective view showing the configuration of the mobile personal computer. In FIG. 7, the personal computer 50 includes a keyboard 51, a main body 52, and a display unit 53 using the organic EL display 10. Even in this case, the display unit 53 using the organic EL display 10 exhibits the same effect as that of the above embodiment. As a result, the personal computer 50 can realize image display with few defects.
[0080]
FIG. 8 is a perspective view showing the configuration of the mobile phone. In FIG. 8, the cellular phone 60 includes a plurality of operation buttons 61, an earpiece 62, a mouthpiece 63, and a display unit 64 using the organic EL display 10. Even in this case, the display unit 64 using the organic EL display 10 exhibits the same effect as that of the above embodiment. As a result, the mobile phone 60 can realize image display with few defects.
[0081]
(Fourth embodiment)
In the present embodiment, a pixel circuit shown in FIG. 9 will be described as an embodiment in which a switching transistor and a detection transistor are combined.
In FIG. 9, each pixel circuit 20 includes a driving transistor Q20 as a second transistor, a first switching transistor Q21 and a second switching transistor Q22, a light emission controlling transistor Q23, and a holding capacitor C1 as a holding element. have. The driving transistor Q20 is composed of a P-channel TFT. The first and second switching transistors Q21 and Q22 and the light emission control transistor Q23 are composed of N-channel TFTs.
[0082]
The drive transistor Q20 has a drain connected to the anode of the organic EL element 21 via the light emission control transistor Q23, and a source connected to the power supply line L1. A drive voltage Vdd for driving the organic EL element 21 is supplied to the power supply line VL. A holding capacitor C1 is connected between the gate of the driving transistor Q20 and the power supply line VL.
[0083]
The gate of the driving transistor Q20 is connected to the drain of the first switching transistor Q21. The source of the first switching transistor Q21 is connected to the drain of the second switching transistor Q22. The drain of the second switching transistor Q22 is connected to the drain of the driving transistor Q20.
[0084]
Further, the source of the second switching transistor Q22 is connected to the single line driving circuit 30 of the data line driving circuit 12 through the data line Xm. The single line driving circuit 30 is provided with a data current generating circuit 40a. The data current generation circuit 40 a outputs a data signal I to the pixel circuit 20. The data line Xm is connected to the data current generation circuit 40a through the first switch Q11 and is connected to the current detection circuit 30b through the second switch Q12.
[0085]
The first and second sub-scanning lines Va and Vb are connected to the gates of the first and second switching transistors Q21 and Q22, respectively. The first and second switching transistors Q21 and Q22 are turned on by the first scanning signal SL1 and the second scanning signal SL2 from the first sub-scanning line Va and the second sub-scanning line Vb. Further, the gate of the light emission control transistor Q23 is controlled by the light emission control signal Gp.
[0086]
When the data current generating circuit 40a outputs the data signal I through the data line Xm while the first switch Q11, the first switching transistor Q21, and the second switching transistor Q22 are on, the pixel circuit 20 The data signal I is supplied, the charge amount corresponding to the data signal I is accumulated in the holding capacitor C1, and the conduction state of the driving transistor is set. This is a write operation.
Subsequently, when the light emission control transistor Q23 is turned on in response to the light emission control signal Gp for turning on the light emission control transistor Q23, a current amount corresponding to the conduction state of the driving transistor Q20 is supplied to the organic EL element 21. Supplied.
[0087]
On the other hand, in the test mode, the above write operation is basically the same, but the amount of charge corresponding to the test signal is held in the holding capacitor instead of the normal data signal. Next, the second switching transistor Q22 and the second switch Q12 are turned on while the first switching transistor Q21, the first switch Q11, and the light emission control transistor Q23 are turned off, and the driving transistor is turned on. The current detection circuit 30b detects the amount of current passing through Q20.
In the fourth embodiment, unlike the first embodiment, instead of newly providing a detection transistor, one of the two switching transistors (second switching transistor Q22) is also used as a detection transistor. Yes.
[0088]
In addition, embodiment of invention is not limited to the said embodiment, You may implement as follows.
In the first embodiment, the display is inspected using the inspection device 19 that inspects the organic EL display before shipment. With respect to portable electronic devices such as mobile phones, PDAs, notebook computers, etc., when the battery of the portable electronic device is charged with a charger, the organic EL display mounted on the portable electronic device during the charging is checked by the inspection device 19. You may make it test | inspect. In this case, it is necessary to incorporate an inspection device in the charger. When charging is started, the test mode is entered, and each pixel circuit 20 is inspected by performing current detection. By doing in this way, it can correct | amend every time the operation characteristic by the secular change of each pixel circuit 20 is charged about the organic electroluminescent display mounted in the portable electronic device.
[0089]
In the above embodiment, the inspection device 19 is provided with the current detection circuits 19a for all the pixel circuits 20 of the display panel unit 11. However, as in the second embodiment, the number of data lines X1 to Xm is the same. You may implement. In this case, after each pixel circuit 20 connected on one scanning line is inspected as in the second embodiment, each pixel circuit on the next scanning line is inspected.
[0090]
In the first embodiment, the correction value Vd obtained by the inspection device 19 is stored in the memory 17a built in the control circuit 17, and a new data voltage Vdata is created using the correction value Vd stored in the memory 17a.
[0091]
In the above-described embodiment, the pixel circuit 20 is embodied as an electronic circuit to obtain a suitable effect. However, the embodiment is specifically applied to an electronic circuit that drives a driven element other than the organic EL element 21 such as a light emitting element such as an LED or an FED. May be used. There is a magnetic RAM as a driven element. Therefore, the present invention may be applied to a memory device using the magnetic RAM.
[0092]
In the embodiment, when the correction value ΔVd is obtained, a test is performed using two different test data voltages Vdata. This may be performed by performing a test using one test data voltage Vdata or performing a test using three or more test data voltages Vdata.
In the above-described embodiment, the current is supplied to the current detection circuit via the data lines X1 to Xm. However, a detection-dedicated wiring is provided in the detection transistor Q13, and the current is supplied to the current detection circuit 1 via these wirings. You may make it carry out.
[0093]
In the above embodiment, the organic EL element 21 is embodied as the driven element of the pixel circuit. However, the organic EL element 21 may be embodied as an inorganic EL element. That is, you may apply to the inorganic EL display which consists of an inorganic EL element.
[0094]
In the above embodiment, the pixel circuit 20 is embodied as a voltage-driven pixel circuit, but may be applied to an organic EL display of a current-driven pixel circuit. Further, it may be applied to an organic EL display in a pixel circuit that is digitally driven such as time division and area gradation.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram showing a circuit configuration of an organic EL display according to an embodiment.
FIG. 2 is a block circuit diagram showing an internal circuit configuration of a display panel unit and a data line driving circuit.
FIG. 3 is a circuit diagram showing an internal circuit configuration of a pixel circuit.
FIG. 4 is a timing chart of each signal in a normal mode.
FIG. 5 is a timing chart of each signal in a test mode.
FIG. 6 is a main part electric block circuit diagram for explaining a second embodiment;
FIG. 7 is a perspective view showing the configuration of a mobile personal computer for explaining a third embodiment.
FIG. 8 is a perspective view showing a configuration of a mobile phone for explaining a third embodiment.
FIG. 9 is a circuit diagram showing an internal circuit configuration of a pixel circuit according to a fourth embodiment.
[Explanation of symbols]
C1 Retention capacitor as a capacitive element
Q11 Driving transistor as second transistor
Q12 Switching transistor as the first transistor
Q13 Light emission control transistor as the fourth transistor
Q14 Detection transistor as third transistor
Y1-Yn scan line
Va first sub-scan line
Vb second sub-scan line
X1-Xm data line
10 Organic EL display as an electro-optical device
11 Display panel
17 Control circuit constituting correction value calculation circuit
17a Memory as memory circuit
19 Inspection apparatus constituting correction value calculation circuit
19a Current detection circuit
20 Pixel circuit as electronic circuit
21 Organic EL elements as driven elements
31a Current detection circuit

Claims (9)

An electronic device comprising a plurality of scanning lines, a plurality of data lines, and a plurality of unit circuits arranged corresponding to intersections of the plurality of scanning lines and the plurality of data lines ,
Each of the plurality of scanning lines includes a first sub-scanning line and a second sub-scanning line,
Each of the plurality of unit circuits is
A first transistor having a gate connected to the first sub-scanning line ;
A holding element that holds a voltage signal supplied via the first transistor as an electric quantity;
A second transistor whose conduction state is controlled based on the amount of electricity held in the holding element;
A driven element to which a current corresponding to a conduction state of the second transistor is supplied from the second transistor ;
A third transistor having a gate connected to the second sub-scanning line and connected in series with the second transistor;
One of the source and drain of the first transistor is connected to the data line, and the other is connected to the gate of the second transistor,
One of the source and drain of the third transistor is connected to the first transistor, and the other is connected to the second transistor,
During a period in which the voltage signal is supplied to the holding element through the first transistor, the third transistor is turned off.
During the period of detecting the amount of current corresponding to the conduction state of the second transistor, the third transistor is turned on and passes through a current path including the second transistor and the third transistor. An electronic device characterized by detecting the amount of current. The electronic device according to claim 1,
A gate is connected to the second sub-scanning line, and one of a source and a drain is connected to the second transistor, and the other is further provided with a fourth transistor connected to the driven element. Electronic device to play. The electronic device according to claim 1 or 2,
The electronic device, wherein the driven element is a current driving element. The electronic device according to claim 2.
In the period for detecting the amount of current, the fourth transistor is at least in an off state,
An electronic device characterized by the above. The electronic device according to any one of claims 1 to 4 ,
The current path does not include the driven element;
An electronic device characterized by the above. A plurality of scanning lines, a plurality of data lines, and a plurality of unit circuits arranged corresponding to intersections of the plurality of scanning lines and the plurality of data lines,
Each of the plurality of scanning lines includes a first sub-scanning line and a second sub-scanning line,
Each of the plurality of unit circuits is
A first transistor having a gate connected to the first sub-scanning line; a holding element that holds a voltage signal supplied via the first transistor as an electric quantity; and an electric quantity held by the holding element a second transistor, the conduction state is set based on, from said second Trang register, a driven element current corresponding to the conduction state of the second transistor is supplied, the second sub-scan line And a third transistor connected in series with the second transistor, and
One of the source and drain of the first transistor is connected to the data line, and the other is connected to the gate of the second transistor,
One of the source and the drain of the third transistor is connected to the first transistor, and the other is connected to the second transistor .
A first step of turning off the third transistor and turning on the first transistor to hold an electric quantity based on the voltage signal in the holding element;
As an off-state the third transistor from the second transistor, and a second step of supplying a current corresponding to the conduction state of the second transistor in the driven element,
During the period of detecting the amount of current corresponding to the conduction state of the second transistor, the third transistor is turned on and passes through a current path including the second transistor and the third transistor. And a third step of detecting the amount of current.
A method for driving an electronic device. A plurality of scanning lines, an electro-optical device including a plurality of data lines, and a plurality of pixel circuits arranged corresponding to intersections of the plurality of scanning lines and the plurality of data lines,
Each of the plurality of scanning lines includes a first sub-scanning line and a second sub-scanning line,
Each of the plurality of pixel circuits is
A first transistor having a gate connected to the first sub-scanning line, the conduction of which is controlled by a scanning signal supplied through a corresponding scanning line of the plurality of scanning lines;
A holding element for holding a voltage signal supplied via the corresponding data line of the plurality of data lines and the first transistor as an electric quantity;
A second transistor whose conduction state is controlled based on the amount of electricity held in the holding element;
An electro-optic element to which a current corresponding to a conduction state of the second transistor is supplied from the second transistor ;
A third transistor having a gate connected to the second sub-scanning line and connected in series with the second transistor;
One of the source and drain of the first transistor is connected to the data line, and the other is connected to the gate of the second transistor,
One of the source and drain of the third transistor is connected to the first transistor, and the other is connected to the second transistor,
During a period in which the voltage signal is supplied to the holding element through the first transistor, the third transistor is turned off.
During the period of detecting the amount of current corresponding to the conduction state of the second transistor, the third transistor is turned on and passes through a current path including the second transistor and the third transistor. An electro-optical device that detects a current amount of a current. The electro-optical device according to claim 7 .
Detecting the amount of current through the third transistor and a corresponding data line among the plurality of data lines;
An electro-optical device. An electronic apparatus in which the electro-optical device according to claim 7 is mounted.

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