JP4889926B2 - Display device and driving method thereof - Google Patents

Description

  The present invention relates to a display device, and more particularly to a display device having self-light emitting elements arranged in an active matrix type and a driving method thereof. The present invention also relates to a semiconductor integrated circuit mounted on a display device.

  In recent years, research and development of display devices using light-emitting elements (self-light-emitting elements) have been advanced. Such a display device is widely used as a display screen of a mobile phone or a monitor of a personal computer, taking advantage of high image quality, thinness, and light weight. In particular, such a display device has features such as a fast response speed suitable for moving image display, low voltage, low power consumption drive, etc., so that it can be used in a wide range including a new generation of mobile phones and personal digital assistants (PDAs). Applications are expected.

  A light-emitting element is also called an organic light emitting diode (OLED), which contains an organic compound or an inorganic compound between an anode, a cathode, and the anode and the cathode, and an electric field is applied between the anode and the cathode. It has a light emitting layer (hereinafter referred to as an electroluminescent layer). There is a fixed relationship between the amount of current flowing through the light emitting element and the luminance of the light emitting element, and the light emitting element emits light at a luminance corresponding to the amount of current flowing through the electroluminescent layer.

  By the way, as a method for inputting a signal to a pixel when displaying a multi-gradation image on a display device using a light emitting element, an analog gradation method (analog driving method) and a digital gradation method (digital driving method) are used. Can be mentioned. The difference between the two systems is in the method of controlling the light emitting element in each of the light emitting and non-emitting states of the light emitting element.

  The analog gradation method is a method in which gradation is obtained by controlling a current flowing through a light emitting element. The digital gray scale method is a method in which the light emitting element is driven only in two states: an on state (a state where the luminance is approximately 100%) and an off state (a state where the luminance is approximately 0%). However, since the digital gradation method can display only two gradations as it is, a driving method for displaying a multi-gradation image in combination with another method such as a time gradation method or an area gradation method has been proposed. . For example, time gradation display is to divide one frame into several subframes, give weight to each light emission time, and perform gradation display by selection. The area gradation method is a method in which sub-pixels are provided in a pixel, the light emitting area is weighted, and gradation display is performed by selection.

  Driving methods for displaying a multi-tone image on a display device using a light-emitting element are roughly classified into a voltage input method and a current input method. As the voltage input method and the current input method, both the analog gradation method and the digital gradation method described above are applied.

  The voltage input method is a method in which a video signal having a voltage value is input to a pixel, input to a gate electrode of a driving element included in the pixel, and the luminance of the light-emitting element is controlled using the driving element. In this case, if analog gradation is applied, it is easily affected by variations in TFTs.

  The current input method is a method in which the luminance of the light emitting element is controlled by supplying a set signal current to the driving element of the pixel and flowing the signal current from the driving element to the light emitting element. In the case of the current input method, multiple gradations are displayed depending on the value of the current flowing to the light emitting element. In this way, since the current is input as a signal, the writing time becomes long.

  The luminance of the light emitting element included in the display device as described above deteriorates with time (hereinafter referred to as deterioration with time) as described below. Looking at the graph of the voltage applied to the light-emitting element with respect to the current to the light-emitting element shown in FIG. 15A, when a certain voltage V0 is applied, a predetermined light emission luminance is obtained with the current Ia. Due to deterioration over time, even when the voltage V0 is applied, only the current Ib flows to the light emitting element, and thus a predetermined luminance cannot be obtained.

  As can be seen from the graph of current luminance characteristics of the light-emitting element shown in FIG. 15B, a certain light-emitting element can obtain the luminance La at the current value I0, but it decreases to the luminance Lb with time.

  This is considered to be because the light emitting element generates heat when a voltage or current is passed, and the film quality of the electroluminescent layer is deteriorated or the interface between the electroluminescent layer and the electrode is deteriorated. Further, since the deterioration state of the light emitting element is different for each light emitting element, burn-in occurs.

  Therefore, in the case of the voltage input method, a display that can correct a video signal (video signal) based on correction data stored in advance according to the degree of deterioration of the self-luminous element and obtain a uniform screen without uneven brightness. An apparatus has been proposed (see Patent Document 1). More specifically, in the case of multi-gradation display by the time gradation method, 1-bit subframe is used for video signal correction. For example, in the case of a self-display device using 6-bit digital gradation, a processing capability for 1 bit is added as an extra for correction, and a 7-bit digital gradation is designed and manufactured. Then, in the normal operation, the lower 6 bits are used, and when the light emitting element is deteriorated, the correction value is added to the normal digital video signal, and the signal processing for the addition is 1 for addition. This is done using bits.

Further, as shown in FIG. 18, there is a method in which a voltage input method and a current input method are combined. In this method, each pixel included in the light emitting display device includes a plurality of transistors PchTFT1 to PchTFT1-3 having a current capability ratio with a gate short-circuited. Then, after storing a state in which the current supply capability of each of the plurality of transistors is proportional to an arbitrary current value, whether or not to supply current to the light-emitting element is determined by switches SW1A to SW1A between the drains of the plurality of transistors and the light-emitting element. SW3A is controlled to be turned on / off according to digital gradation data D0 to D2, thereby supplying a high-accuracy current to the light-emitting element that is only affected by variations in characteristics of transistors in adjacent regions (see Patent Document 2).
JP 2002-175041 A JP 2003-66909 A

  As described above, in the display device, the degree of deterioration differs for each light emitting element. As a result, even when it is desired to make the entire pixel emit light with the same luminance, pixels with advanced deterioration vary and this deteriorated pixel is adjacent to a pixel with no deterioration or little deterioration. In some cases, burn-in occurs in which the deteriorated pixel looks darker. As a result of this burn-in, display unevenness of the display device occurs.

  Since the display device using the voltage input method described in Patent Document 1 corrects the video signal, when the magnitude of the corrected video signal, that is, the length of the lighting time becomes the maximum value, the lighting time is further increased. The video signal cannot be increased. Furthermore, the gradation representation ability on the actual display is inferior to the original gradation representation ability. That is, as described above, in a panel that can express a 7-bit gradation, since 1 bit is used for correction, only 6 bits can be displayed.

  Further, as described above, in the case of the voltage input method adapted to the analog gradation, it is easily affected by variations in TFTs. Further, in the current input method, the signal current writing time has become longer.

  Even when the correction method described in Patent Document 1 is combined with the pixel configuration described in Patent Document 2, the digital gradation data D0 to D2 are corrected, and the problem in the previous paragraph cannot be solved. That is, for example, one of the digital gradation data D0 to D2 is used for correction, so that one bit is used for correction in a panel that can express a three-bit gradation. However, the gradation display ability on the actual display is inferior to the original gradation expression ability.

  Accordingly, it is an object of the present invention to provide a display device in which a current supplied to a light emitting element is corrected in accordance with the degree of deterioration of the light emitting element and display unevenness caused by the deterioration of each light emitting element is reduced. To do. Another object of the present invention is to provide a display device which is not affected by variations in TFTs and has a short signal writing time.

  In view of the above problems, the present invention is characterized in that, unlike video signal correction, a current value supplied to a light emitting element is corrected in accordance with deterioration of the light emitting element.

  In order to achieve the above, one embodiment of the present invention includes a supply source that supplies at least a correction current based on deterioration of a light-emitting element, and a current source that supplies a correction current from the supply source to the light-emitting element. It is a display device.

  Another embodiment of the present invention is a light-emitting element provided at least at an intersection of a signal line and a scanning line, a supply source that supplies a correction current based on deterioration of the light-emitting element, and the supply source to the light-emitting element. A first source connected to the signal line and the scanning line, and a second switch provided between the current source and the light emitting element. It is a display device characterized by this.

  Another aspect of the present invention is a supply source that supplies a correction current based on at least deterioration of the light emitting element, a control unit that controls the supply source, a current source that supplies a correction current from the supply source to the light emitting element, It is a display device characterized by having.

  Another embodiment of the present invention is a light-emitting element provided at an intersection of at least a signal line and a scanning line, a supply source that supplies a correction current based on deterioration of the light-emitting element, and a control that controls the supply source And a first switch connected between the signal line and the scanning line, and provided between the current source and the light emitting element. And a second switch.

  According to another aspect of the present invention, there is provided a counting means comprising at least means for counting the lighting time of the light emitting element, means for setting a correction signal based on the lighting time and deterioration of the light emitting element, and a correction current based on the correction signal. A display device comprising: a supply source that supplies a light source; a control unit that controls a correction signal that is input to the supply source; and a current source that supplies a correction current from the supply source to the light emitting element.

  Another embodiment of the present invention is a light-emitting element provided at least at the intersection of a signal line and a scanning line, means for counting the lighting time of the light-emitting element, and a correction signal based on the lighting time and deterioration of the light-emitting element. A counting means, a supply source for supplying a correction current based on the correction signal, a control means for controlling a correction signal input to the supply source, and a correction current from the supply source to the light emitting element. A first switch connected to the signal line and the scan line, and a second switch provided between the current source and the light emitting element. It is a display device.

  Another aspect of the present invention includes storage means for storing at least deterioration information of the light emitting element, means for counting the lighting time of the light emitting element, and means for setting a correction signal based on the lighting time and the deterioration information. A counting unit; a supply source that supplies a correction current based on the correction signal; a control unit that controls a correction signal input to the supply source; and a current source that supplies the correction current from the supply source to the light emitting element. It is a display device characterized by this.

  Another embodiment of the present invention is a light-emitting element provided at an intersection of at least a signal line and a scanning line, storage means for storing deterioration information of the light-emitting element, and means for counting the lighting time of the light-emitting element. Means for setting a correction signal based on the lighting time and deterioration information, a counting means, a supply source for supplying a correction current based on the correction signal, and a control means for controlling the correction signal input to the supply source, A current source for supplying a correction current from the supply source to the light emitting element, a first switch connected to the signal line and the scanning line, and a second switch provided between the current source and the light emitting element. It is a display device characterized by having.

  In the present invention, the supply source includes a current source, and the current source is provided for each signal line.

  In the present invention, the supply source has a pair of first current source and second current source, and the pair of current sources is provided for each signal line.

  In the present invention, the current source that supplies the correction current has a transistor and a capacitor that holds the voltage between the gate and the source of the transistor.

  In the present invention, the current source and the supply source are connected via a current line.

  In the present invention, the control means includes a shift register or a decoder.

  In the present invention, the control means includes a shift register or decoder, a first latch circuit, and a second latch circuit.

  In the present invention, the current source included in the control means and the current source included in the supply source can be shared.

  In the present invention, the shift register and the latch circuit included in the control unit and the shift register and the latch circuit included in the signal line driver circuit that drives the signal line can be shared.

  Another embodiment of the present invention is characterized by including a semiconductor integrated circuit that stores deterioration information of a light emitting element and calculates a correction signal corresponding to the information.

  One aspect of the semiconductor integrated circuit of the present invention includes storage means for storing deterioration information of a light emitting element, means for counting the lighting time of the light emitting element, and means for setting a correction signal based on the lighting time and the deterioration information. And counting means.

  In the semiconductor integrated circuit of the present invention, the means for counting the lighting time of the light emitting elements of the counting means has a counter circuit.

  In the semiconductor integrated circuit of the present invention, the storage means has a nonvolatile memory, and the nonvolatile memory records deterioration information of the light emitting element.

  In the semiconductor integrated circuit of the present invention, the storage means includes a nonvolatile memory and a volatile memory, and display information is recorded in the volatile memory.

  Further, the memory means and the counting means included in the semiconductor integrated circuit of the present invention include semiconductor elements provided on a silicon wafer.

  In the display device having the above structure, the first current source supplies a correction current corresponding to the deterioration of the light emitting element having the smallest deterioration among the light emitting elements connected to the same signal line, and the second current. The light source can be driven by the source so that a correction current corresponding to the deterioration of the light emitting element having the greatest deterioration among the light emitting elements connected to the same signal line is supplied.

  In the display device having the above structure, the first current value corresponding to the light emitting element with the least deterioration among the light emitting elements connected to the same signal line and the second current corresponding to the light emitting element with the largest deterioration. A plurality of current values can be determined by dividing a current value between the current value and a plurality of current values including a first current value and a second current value can be supplied by a plurality of current sources. .

  In such a driving method, the number of the plurality of current values determined by dividing the current value is the same as the number of current sources. In addition, deterioration of the light-emitting element can be corrected using a video signal input to the signal line.

  One embodiment of the present invention is a digital method in which a switch portion is driven using a digital video signal, and a predetermined signal current is supplied to a light-emitting element or not, and a light-emitting state and a non-light-emitting state are switched. Further, multi-tone expression is performed by time gradation.

  In the present invention, one or a plurality of current sources for supplying a correction current from the supply source to the light emitting element, that is, a current source connected to the light emitting element can be provided.

  In the present invention, there are no limitations on the types of transistors that can be used, and thin film transistors (hereinafter also referred to as TFTs) using non-single crystal semiconductor films typified by amorphous silicon and polycrystalline silicon, semiconductor substrates, and SOI substrates. MOS transistors, junction transistors, transistors using organic semiconductors or carbon nanotubes, and other transistors can be used. There is no limitation on the kind of the substrate over which the transistor is provided, and the transistor can be provided on a single crystal substrate, an SOI substrate, a glass substrate, or the like.

  Although the display device having a light emitting element has been described above, the applicable range of the present invention is wide, and it is applied when a current value corrected according to a change (deterioration, etc.) of a load can be supplied to the load. Is possible.

  According to the present invention, the signal current supplied to the light emitting element can be corrected with the aging of the light emitting element, and display unevenness due to image sticking can be reduced. In addition, according to the present invention, by setting a signal current corresponding to the deterioration of the light emitting element, it is possible to prevent a decrease in luminance due to the deterioration of the light emitting element and to prevent a decrease in image display quality.

  In addition, the pixel structure of the present invention can provide a display device in which the influence of variation in the driving current source is reduced.

  Furthermore, according to the present invention, it is possible to set a corrected signal current according to the deterioration of each light emitting element. Therefore, it is possible to drive the light emitting element with higher accuracy than in the case of correcting the signal current according to the most deteriorated light emitting element, and to further reduce power consumption.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention can be implemented in many different modes, and it is easy for those skilled in the art to make various changes in form and details without departing from the spirit and scope of the present invention. Understood. Therefore, the present invention is not construed as being limited to the description of this embodiment mode. Note that in all the drawings for describing the embodiments, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

(Embodiment 1)
In this embodiment mode, functions and a configuration of the display device of the present invention will be described.

  As shown in FIG. 1A, the display device of the present invention, in particular, a pixel includes a light source 11 and a current source connected to the light source 11 via a switch (SW) 12 (hereinafter referred to as a driving current source). 13). The switch 12 has a function of switching between a light emitting state and a non-light emitting state by selecting whether or not to flow a constant current from the current source to the light emitting element 11 based on the video signal 18. The drive current source 13 is connected to the power line 20 and is controlled by a signal 19 (hereinafter referred to as a control signal) different from the video signal 18. A device other than the switch 12 may be provided between the light emitting element 11 and the driving current source 13. That is, the light emitting element 11 and the driving current source 13 may be electrically connected.

  A control signal 19 is input to the drive current source 13. As a result, the driving current source 13 can flow a constant current without being affected by variations in the current characteristics of the transistors constituting the current source. The magnitude of the current flowing through the drive current source 13 is set by the control signal 19. In the present invention, the magnitude of the current (also referred to as signal current) supplied by the driving current source 13 is a magnitude corresponding to the degree of deterioration of the light emitting element 11. That is, the magnitude of the current set by the control signal 19 is a magnitude corresponding to the degree of deterioration of the light emitting element 11. That is, the drive current source 13 can pass a current having a magnitude corrected according to the deterioration of the light emitting element. For example, when the deterioration of the light emitting element 11 is severe, the magnitude of the current set by the control signal 19 becomes large. As a result, the magnitude of the current that the driving current source 13 passes through the light emitting element 11 is increased. Therefore, as a result, a decrease in luminance of the light emitting element 11 can be suppressed. On the other hand, when the deterioration of the light emitting element 11 is light, the magnitude of the current set by the control signal 19 does not increase so much. As a result, the magnitude of the current that the driving current source 13 passes through the light emitting element 11 does not increase so much. Therefore, as a result, a decrease in luminance of the light emitting element 11 can be suppressed. As described above, since the magnitude of the current supplied by the driving current source 13 is set in accordance with the deterioration of the light emitting element 11, it is difficult to reveal the deterioration of the light emitting element 11, and burn-in or the like can be prevented. .

  Further, as shown in FIG. 1B, a plurality of driving current sources 13a to 13c may be provided in the display device of the present invention, particularly in the pixel. In this case, a plurality of switches SW12a to SW12c are provided in accordance with a plurality of control signals 19 and a plurality of driving current sources 13a to 13c for controlling the plurality of driving current sources 13a to 13c, and a plurality of videos are supplied to the plurality of switches. A signal 18 is provided.

When a plurality of drive current sources 13a to 13c are used in this way, gradation display with the number of bits corresponding to the drive current sources 13a to 13c can be performed. For example, the current I ₁ = 2 × I ₀ can be supplied from _one driving current source, and I ₁ = 4 × I ₀ can be supplied from the other driving current source.

  1A and 1B, the display device having the pixel of the present invention includes a light emitting element 11, a switch 12, and a driving current source 13, as shown in FIG. 10, a signal supply source 14 for setting a signal current corresponding to the deterioration of the light emitting element, a control unit 15 for controlling the signal supply source 14, and information on the deterioration of the light emitting element are recorded in the driving current source 13. It has storage means 16 and counting means 17 for measuring the deterioration state of the light emitting element.

  Note that in the present invention, a current source included in a storage unit or a signal supply source may be provided in each pixel.

  In FIG. 1 (C), the storage means 16 and the counting means 17 provide information regarding correction of the deterioration state of the light emitting element and the value of the signal current to be corrected according to the deterioration state (hereinafter referred to as a correction signal). To be created). The correction signal is input to the control unit 15, and the control unit 15 sets a current in the signal supply source 14. Then, a current is set in the drive current source 13 based on the current value of the signal supply source 14. As a result, the corrected signal current is supplied from the driving current source 13 to the light emitting element 11.

  In the present invention, setting the driving current source so as to have a capability of supplying a predetermined signal current is referred to as setting of the signal current, and in particular, the signal corrected according to the deterioration state of the light emitting element of each pixel. Setting so as to supply current is referred to as setting of a corrected signal current.

  Note that the signal supply source only needs to have a function of setting the signal current corrected based on the correction signal to the driving current source of each pixel. For example, the signal supply source includes a current source. The current source is preferably connected to each signal line. Furthermore, a plurality of the current sources may be connected for each signal line. At this time, one current source is referred to as a reference current source, the other current source is referred to as a correction current source, and the reference current source and the correction current source are classified according to the correction method.

  The control means only needs to have a function of inputting a correction signal created from the storage means 16 and the counting means 17 and setting a current to the signal supply source based on the correction signal. It has a latch circuit.

  Furthermore, the current source included in the signal current source and the current source included in the latch circuit can be shared. As a result, the area occupied by the drive circuit unit can be reduced, and a narrow frame can be achieved.

  Further, in the signal line driving circuit, in the case of line sequential driving in which video signals are input all at once to a row of light emitting elements, the signal line driving circuit has a latch circuit and a shift register, and is point sequential in which video signals are input for each light emitting element. In the case of driving, it is sufficient to have a shift register.

  The storage means only needs to have at least storage means such as a nonvolatile memory or a magnetic memory, and the deterioration information (deterioration data) of the light emitting element is recorded in the nonvolatile memory or the like. Furthermore, it has a volatile memory and records display information. The deterioration data includes basic data in which a change in current value for obtaining a constant luminance is recorded in the light emitting element and accumulated data in which deterioration of the light emitting element over time is stored.

  The basic data is obtained by driving one test light emitting element and measuring deterioration with time in advance. For example, as shown in FIG. 11, aging is performed using a test element including a current source 90 and a light-emitting element 91, and in the light-emitting element, a current for obtaining a certain luminance, that is, time-lapse. A current corresponding to the deterioration is recorded in the nonvolatile memory 92.

  Accumulated data can be obtained sequentially by measuring the deterioration over time of each light emitting element in an actual display device. For example, the lighting time of the light emitting element (the time during which the light emitting element is actually lit) is measured from the video signal by a counter circuit included in the counting means. Then, with reference to the basic data, the deterioration of the light emitting element is estimated based on the lighting time of the light emitting element, and the deterioration is accumulated.

  From such basic data and accumulated data, the deterioration of the light emitting element is grasped, and a signal indicating how much the signal current is corrected by the counting means, that is, a correction signal is determined. For example, a correction signal corresponding to the lighting time of the light emitting element is determined by the counting means based on the storage means, and is input to the control means. At the same time, the corrected correction signal current is stored in the accumulated data.

  Note that the current source or circuit included in the above-described means of the display device of the present invention can be formed using a transistor, specifically, a thin film transistor having N-type or P-type polarity. Further, in the case of forming with a thin film transistor having a polycrystalline semiconductor film, the pixels, the signal supply source, and the control means can be integrally formed on the same substrate. Needless to say, the pixel and the signal supply source and the control unit or the pixel and the signal supply source and the control unit may be formed on different substrates.

  The counting unit and the storage unit may be formed separately from the pixel portion, and for example, a semiconductor element (transistor) provided on a silicon wafer may be used. The counting means and the storage means separately formed in this way are connected to the pixels, the signal supply source and the control means by an anisotropic conductive film (ACF) or a flexible printed circuit (FPC). That's fine.

  According to the present invention, the signal current supplied to the light emitting element can be corrected with the aging of the light emitting element, and display unevenness due to image sticking can be reduced. Furthermore, in the pixel configuration of the present invention, since the signal current is set so that the light emitting element emits a constant luminance, a display that reduces the influence of variations in the driving current source, specifically, the transistors constituting the current source. An apparatus can be provided.

(Embodiment 2)
In this embodiment mode, a specific pixel structure of the present invention will be described with reference to FIG.

  As shown in FIG. 2A, the pixel includes at least a light emitting element 11 and a switch (SW) 12 provided in a region surrounded by a broken line, a driving current source 13, a capacitive element 32, and a driving current source. And a switch (SW) 34 provided between the light emitting element 11 and the light emitting element 11. The switch 12 is connected to the signal line 36 and the scanning line 37, and the driving current source and the capacitive element 32 are connected to the power supply line 20. A signal from the signal supply current source 40 which is a signal supply source is input to the drive current source via the current line 39. As described above, the signal supply current source 40 is controlled by the control means. A signal for controlling the switch 34 is input to the driving current source.

  Further, as shown in FIG. 2B, a plurality of driving current sources 13a and 13b may be provided. In this case, a plurality of control signals for controlling the plurality of drive current sources 13a and 13b, that is, a plurality of signal supply current sources 40a and 40b, and a plurality of current lines 39a and 39b connected thereto, Between the driving current sources 13a and 13b and the light emitting element 11, a plurality of switches SW34a and SW34b for controlling whether or not current is supplied to the light emitting element 11 are provided. In addition, a plurality of switches SW12a and SW12b and signal lines 36a and 36b for supplying a plurality of video signals supplied to the plurality of switches are provided according to the plurality of driving current sources 13, and the plurality of switches SW12a and SW12b and the power source are provided. A plurality of capacitive elements 32a and 32b are provided between the lines.

  When a plurality of driving current sources are used as described above, gradation display with the number of bits corresponding to the driving current sources can be performed.

  Next, a specific configuration of the driving current source 13 will be exemplified to describe the pixel configuration of the present invention.

  In FIG. 3A, the signal line 36 and the scanning line 37 are connected to a transistor 70 that functions as the switch 31. Further, a transistor 71 functioning as the switch 34 is provided, and the capacitor 32 is provided between the gate electrode of the transistor 71 and the power supply line 38. The light emitting element 35 is connected to one electrode of the transistor 71. The driving current source 13 surrounded by a broken line is provided with a p-channel transistor 72 that functions as a switch. A p-channel transistor 73 and an n-channel transistor 75 are provided on one electrode of the transistor 72. Is provided. The gate electrode of the transistor 72 is connected to the first control line 77. A capacitive element 51 for holding the gate-source voltage of the transistor 73 is provided. One electrode of the n-channel transistor 74 connected to the gate electrode of the transistor 73 is connected to the current line 39. The gate lines of the n-channel transistors 74 and 75 are connected to the second control line 78.

  Next, the operation of such a pixel configuration will be described.

  First, a current source that functions as a signal supply source is set so that a corrected signal current flows. The transistors 74 and 75 are selected by the second control line 78 and turned on. Then, a current flows from the power supply line 38 to the p-channel transistor 73 and the n-channel transistor 75, and a current flows to the capacitor element 51 and the n-channel transistor 74. The sum of the currents is equal to the amount of current that the signal source has. Then, electric charge is accumulated in the capacitor 51 until the transistor 73 has a gate-source voltage necessary for flowing the corrected signal current. As a result, the transistor 73 has a function of flowing a corrected signal current from the current source of the signal supply source.

  Note that the transistor 73 and the current flowing through the current source of the signal supply source do not necessarily have to be set to flow the same current. For example, what is necessary is just to have a proportional relationship. That is, by changing the L / W ratio between the L / W of the transistor 73 and the transistor constituting the current source of the signal supply source in the current mirror configuration, the amount of current that the transistor 73 needs to flow is changed. Can do.

  After that, a signal for turning off the transistors 74 and 75 and turning on the transistor 72 is input. In such a situation, a video signal is input from the signal line 36 to the capacitor 32 via the transistor 70. When a signal for turning on the transistor 71 is input, a corrected signal current is supplied from the transistor 73 to the light emitting element 35.

  Next, FIG. 3B illustrates an example in which the polarity of the transistor functioning as the driving current source 13 (the transistor 73 in FIG. 3A) is an n-channel type. It has an n-channel transistor 81 that functions as a current source, a power supply line 38 connected to one electrode of the transistor 81, and a capacitor 51 that holds the gate-source voltage of the transistor 81. A p-channel transistor 82 and a transistor 83 are provided on the other electrode of the transistor 81. Further, an n-channel transistor 84 having one electrode connected to the gate electrode of the transistor 81 is provided, and the other electrode of the transistor 84 is connected to the current line 39. The gate electrodes of the transistors 82, 83, 84 are connected to the first control line 77. Note that other structures are the same as those in FIG. 3A, and thus description thereof is omitted here. In this configuration, the second control line is not necessary. Even when the transistor functioning as the driving current source 13 is a p-channel transistor, the second control line can be eliminated by changing the polarity or connection of other transistors.

  Next, operation of the pixel configuration illustrated in FIG. 3B is described.

  First, a signal for turning on the transistors 83 and 84 is input from the first control line 77, and the transistor 82 having a different polarity is turned off. Then, current is supplied from the power supply line 38, and current flows to the current source of the signal supply source connected to the current line 39 via the transistor 81, the capacitive element 51, and the transistor 83. At this time, the current source of the signal supply source is set so as to have the ability of the corrected signal current to flow, and the capacitive element 51 holds the charge equal to the corrected signal current. Note that the charge accumulated in the capacitor 51 is accumulated until it becomes equal to the gate-source voltage of the transistor 81. As a result, the transistor 81 has a capability of supplying a corrected signal current.

  Thereafter, a signal for turning on the transistor 82 is input from the first control line, and the transistors 83 and 84 having different polarities are turned off. In such a situation, a video signal is input from the signal line 36 to the capacitor 32 via the transistor 70. When a signal for turning on the transistor 71 is input, the corrected signal current from the transistor 81 is input to the light emitting element 35.

  Although the case where the driving current source 13 is manufactured using a p-channel or n-channel transistor has been described above, the driving current source 13 of the present invention is not limited to the polarity of the transistor. When the polarity of the transistor in FIG. 3 is changed, it is necessary to design appropriately considering the arrangement of the transistor functioning as a capacitive element or a switch. That is, the capacitor element may be arranged so as to hold a gate-source voltage of a transistor functioning as a current source. Note that at this time, it is preferable to dispose the capacitor element between the gate and the source of the transistor because the capacitor element holds the gate-source voltage. The switches may be arranged so that on / off can be controlled, and a plurality of switches may be arranged.

  Other configurations of the above-described pixels, particularly the driving current source 13, are described in Japanese Patent Application Nos. 2002-143882, 2002-143858, 2002-143886, 2002-143888, 2002-143888, and the like. It is also possible to adapt.

  Further, as shown in FIG. 16, the storage means 16 and the correction current source 25 may be included in the pixel. 16 is an enlarged view of a region corresponding to a region surrounded by a dotted line having SW12 and SW34, the capacitive element 32, and the driving current source 13 shown in FIG. A specific correction current source 25 includes a plurality of current sources 25a to 25c, and includes a plurality of switches SW26a to 26c connected to the respective current sources. The correction current source 25 is connected to the drive current source 13, and the drive current source 13 and the correction current source 25 are connected to the light emitting element 11 via the SW 34.

  In such a pixel, a corrected signal current is formed by the correction current source 25 based on the deterioration state of the light emitting element stored in the storage unit 16. Based on the corrected signal current, the corrected signal current is set in the driving current source 13. Thereafter, when the SW 34 is turned on, the corrected signal current is supplied to the light emitting element 11.

  With such a pixel configuration of the present invention, a signal current corrected in accordance with the deterioration of the light emitting element can be supplied to the light emitting element. As a result, a display device with reduced burn-in caused by deterioration of the light-emitting element can be provided.

(Embodiment 3)
There are various methods for correcting the signal current based on the deterioration of the light emitting element. That is, the present invention is characterized in that the current value flowing through the light emitting element, that is, the light emitting element (load) is corrected according to the deterioration of the load, and the method for correcting the current value is any method. Can be used.

  Thus, in this embodiment, a method of correcting a signal current supplied to a light emitting element using two current sources is illustrated. In the present invention, the current source for correcting the signal current may be singular or plural.

  FIG. 12A shows a first current source 21 and a second current source 22 that output the corrected signal current to the driving current source. Each of the first current source is a reference current source and the second current source is a correction current source. The first and second current sources are connected to the same current line. The current line is connected to the pixel, that is, the driving current source 13.

  In addition, as shown in FIG. 12B, the second current source 22 may be provided with a plurality of current sources 24a to 24c. In this case, a plurality of switches SWa to SWc are provided according to the plurality of current sources 24a to 24c and controlled.

  When the second current source 22 is configured using a plurality of current sources in this way, currents corresponding to the current sources 24a to 24c can be supplied to the current lines by controlling the switches SWa to SWc. .

  Using the reference current source and the correction current source as described above, a method for correcting the magnitude of the signal current is specifically described using the deterioration line representing the deterioration of the light emitting element shown in FIGS. explain.

  For the sake of simplicity, the degradation line is shown as a straight line, but the actual degradation line may be a curve. That is, the deterioration line may be obtained by aging the test light emitting element.

  The graph shown in FIG. 13A shows a signal current supplied to the light-emitting element with respect to time when light is emitted with a constant luminance, and the initial current I0 is t = 0 for the light-emitting element to obtain a predetermined luminance. The signal current at. That is, the initial current I0 is a signal current value before deterioration of the light emitting element with time. Since the light emitting element is deteriorated with time, a signal current for obtaining a predetermined luminance increases with time, like the deterioration lines A and B.

  Note that a large number of light-emitting elements are arranged on an actual panel, and deterioration states are different from each other due to an actual lighting time of the light-emitting elements. Therefore, it is necessary to set using a signal current having a magnitude corresponding to the deterioration state of the light emitting element of each pixel. That is, it is necessary to output a signal current having a magnitude corresponding to the deterioration of the light emitting element of each pixel to the pixel (driving current source).

  Therefore, in order to match the deterioration state of each pixel, a case is considered in which a signal current within a certain range is divided according to the magnitude, and a signal current having a magnitude matching the deterioration is set. Note that the display performance, that is, the accuracy of correction is improved as the interval between divisions becomes finer, but the description will be made on the assumption that the range is recognizable by the human eye, for example, 6 bits, that is, 64. Is not limited to this.

  At this time, the first current source outputs a constant current as a reference to the pixel, and the second current source needs to have a capability of supplying 64 (6 bits) signal currents to the pixel. For this reason, the second current source has six current sources, and the current values supplied from the six current sources are preferably I, 2I, 4I, 8I, 16I, and 32I. For example, the L / W ratio of a transistor functioning as a current source may be designed to be 1: 2: 4: 8: 16: 32.

  In FIG. 13, the number of deterioration lines should be the same as the number of light emitting elements, but for convenience, only the deterioration state as indicated by the deterioration line A and the deterioration state as indicated by the deterioration line B are only maximum. Show.

  In such deterioration lines A and B, for example, the deterioration line A is used as a reference line. A signal current based on the degradation line A is output to the pixel by a first current source corresponding to a reference power source. In other words, the signal current set for the first current source changes with the aging of the light emitting element, that is, with time.

  Then, between the signal current IA of the light emitting element A having the minimum deterioration and the signal current IB of the light emitting element B having the maximum deterioration state (division range in the figure. Reference line (deterioration line A) and deterioration line (Corresponding to the difference with B) is divided into 64 pieces. That is, the second current source is set so as to supply a signal current for 6 bits obtained by dividing the divided range into 64 pieces.

  When a certain pixel is selected and a correction signal corresponding to the deterioration of the light emitting element of the pixel is generated, the second current source supplies a corrected signal current to the pixel based on the correction signal. Is set. At this time, the second current source can set a 6-bit signal current.

  In this way, according to the deterioration state of each pixel, the driving current source of each pixel supplies a current having a magnitude corresponding to the deterioration state to the light emitting element. The magnitude of the current of the driving current source of each pixel is set by supplying a current from another current source to the driving current source. Therefore, in order to set the magnitude of the driving current source for each pixel, the magnitude of the current of the current source that supplies current to the driving current source needs to be set according to the deterioration state of each pixel. There is. As the current source, a first current source and a second current source can be used. The first current source outputs the same amount of current to the driving current source in all the pixels, and the second current source uses a current having a magnitude corresponding to the deterioration state of each pixel as the driving current source. Output. Since the first current source and the second current source are connected in parallel, the sum of the first current source and the second current source is supplied to the driving current source of each pixel. The

  In FIG. 13A, since the current of the reference line (deterioration line A) increases with time according to the deterioration of the light emitting element, the range to be divided is minimized, that is, the range to be divided along with deterioration with time is expanded. It is difficult to improve the correction accuracy, that is, display performance.

  Next, the correction method shown in FIG. 13B, for example, a case where the reference line is set to the initial current I0 will be described.

  FIG. 13B is different from FIG. 13A in that the reference line is not a deterioration line due to deterioration with time of the light emitting element, but a constant initial current independent of time. An initial current is set by a first current source that is a reference current source. That is, the first current source may have a function of supplying a constant current value (not necessarily an initial current) without considering deterioration of the light emitting element.

  Then, the second current source sets a signal current considering deterioration with time (deterioration of deterioration lines A to B). That is, the second current source sets (IA-I0) and (IB-I0) which are the differences between the reference line and the deterioration line A or the deterioration line B. Therefore, in FIG. 13B, the range to be divided is the difference between the degradation line of the light emitting element and the reference line (the range to be divided in the drawing), and is divided into 64 pieces.

  Next, the correction method shown in FIG. 13C will be described in which the reference line is changed to a rectangular shape as the light emitting element deteriorates.

  FIG. 13C is different from FIGS. 13A and 13B in that the reference line is rectangular. Then, the signal current is set by the first current source so as to be the reference line. The interval between the rectangles of the reference line may be increased by one step when deterioration with time progresses to some extent, and can be set within a range of the deterioration line A or less.

  Then, the second current source sets a signal current considering deterioration with time (deterioration of deterioration lines A to B). That is, the second current source sets a difference between the reference line and the deterioration line A or the deterioration line B.

  As shown in FIG. 13C, when the reference line is set to be rectangular, the range to be divided into a plurality of areas is not enlarged with time deterioration as compared with FIG. Expected to improve performance.

  Although FIG. 13 illustrates how the reference current source that sets the signal current of the reference line sets the lower limit of the degradation range, there are also many settings for the upper limit of the degradation range. Hereinafter, an example in which the upper limit is set will be described with reference to FIG.

  As shown in FIG. 14A, the reference line is the deterioration line B, and the upper limit of the range to be divided is set. Similarly to FIG. 10A, the signal current based on the degradation line B is set by the first current source. A signal current based on the degradation line is set by the second current source. The subsequent division method and setting method for the light emitting element are the same as those in FIG.

  In FIG. 14B, the reference line is set to a constant current I1, and the upper limit of the range to be divided is set. FIG. 14B is characterized in that a predetermined current value I1 is set as a reference line, and the current I1 is set by the first current source. That is, the first current source supplies a constant current value without considering the deterioration of the light emitting element. Similarly to FIG. 13B, a signal current based on the reference line is set by the first current source. Moreover, the signal current based on the deterioration lines A to B is set by the second current source. Subsequent division methods and setting methods for the light-emitting elements can be performed in the same manner as in FIG.

  In FIG. 14C, the upper limit of the range to be divided is set so that the reference line changes to a rectangular shape as the light emitting element deteriorates. FIG. 14C is characterized in that the reference line is rectangular. Then, the signal current is set by the first current source so as to be the reference line. The interval between the rectangles of the reference lines may be increased by one step when deterioration with time progresses to some extent, and may be set as appropriate within the range of the deterioration line B or more.

  Then, the second current source sets a signal current considering deterioration with time (deterioration of deterioration lines A to B). That is, the second current source sets a difference between the reference line and the deterioration line A or the deterioration line B.

  By dividing and correcting in this way, it is possible to reduce the burden on the first and second current sources and correct the deterioration of the light emitting element within a range that can be recognized by human eyes. Although described in 6 bits, the number of divisions may be set as appropriate according to the application and specifications of the display device.

  Furthermore, when the display becomes rough even when divided and corrected as described above, or when the interval between divisions is increased, the video signal may be controlled and corrected to the correct luminance. For example, when the corrected current value is too large, the video signal is reduced by that amount. Conversely, when the corrected current value is too small, the video signal may be increased by that amount.

As described above, the correction of the current value (signal current) in the present invention has been described with reference to FIG. 13 for setting the lower limit of the degradation range and FIG. 14 for setting the upper limit of the degradation range. The lower limit and the upper limit setting method may be combined in any way.
(Embodiment 4)
In this embodiment, the entire display device is described with reference to FIG.

  The display device shown in FIG. 4 includes a light emitting element provided at each intersection of a signal line and a scanning line, and a driving current source for supplying a corrected signal current to the light emitting element. The pixel portion 400 includes a scanning line driver circuit 401, a shift register 402, a first latch circuit 403, and a second latch circuit 404 for sequentially selecting, that is, driving a scanning line. A signal line driver circuit 405 for inputting a video signal to a signal line, that is, a signal line driving circuit 405, a signal supply source 408 having at least one of a reference current source 406 and a correction current source 407, a shift register 409, a first register The control circuit 412 having the latch circuit 410 and the second latch circuit 411, the correction data storage unit 413, the counting means 415 having the correction circuit 414, at least the nonvolatile memory 416, and further the volatile memory 417. Storage means 418. Note that a decoder may be used instead of the shift register included in the signal line driver circuit or the control means.

  FIG. 5 shows a specific example of the signal supply source 408. The signal supply source 408 includes a reference current source 406 having a plurality of current sources and a correction current source 407 having a plurality of current sources. These current sources 406 and 407 are each connected to a reference current source 509 via current lines.

  A specific example of the reference current source 509 is shown in FIG. In the reference current source 509a connected to the reference current source 406, transistors having the same polarity form a current mirror circuit. For example, p-channel transistors Tr80 and Tr81 are connected so as to form a current mirror circuit.

  The reference current source 509b connected to the correction current source 407 includes a transistor that connects the gate electrodes of transistors having the same polarity and constitutes a current mirror circuit with at least one transistor. For example, p-channel transistors Tr82, Tr83, and Tr84 are included, and a p-channel transistor Tr85 that forms a current mirror circuit with Tr84 is included. In particular, a plurality of transistors such as Tr82 to Tr84 are provided, and a plurality of current values can be supplied by changing the W / L ratio of the transistors.

  The control means 412 also receives a shift register 409 to which a clock signal (S-CLK), a start pulse (S-SP), and a clock inversion signal (S-CLKb) are input, and a correction video signal (Video Data). The first latch circuit 410 includes a second latch circuit 411 to which a latch pulse is input.

  When a correction video signal is input from the control means 412 to a plurality of correction current sources, a current is supplied from the reference power supply line, and a signal current is set based on the correction video signal. Similarly, the corrected signal current is set by the reference current source 406.

  Such a corrected signal current is supplied from the signal supply source 408 to the driving current source of each pixel through the current line. When the video signal supplied from the signal line is turned on, the light emitting element emits light based on the corrected signal current.

  Next, a specific operation of the display device having such a configuration will be described.

  First, operations of the shift register, the first latch circuit, and the second latch circuit included in the signal line driver circuit are described. The shift register is configured using a plurality of columns of flip-flop circuits (FF) and the like, and receives a clock signal (S-CLK), a start pulse (S-SP), and a clock inversion signal (S-CLKb). Sampling pulses are sequentially output according to the timing of these signals.

  The sampling pulse output from the shift register is input to the first latch circuit. The correction signal video signal is input to the first latch circuit, and the video signal is held in each column in accordance with the timing at which the sampling pulse is input.

  When the first latch circuit completes holding the video signal up to the last column, a latch pulse is input to the second latch circuit during the horizontal blanking period, and the video signal held in the first latch circuit is Are simultaneously transferred to the second latch circuit. Then, one row of the video signal held in the second latch circuit is input to the pixel portion at the same time.

  While the video signal held in the second latch circuit is being input to the pixel portion, the shift register outputs a sampling pulse again. Thereafter, this operation is repeated to process a video signal for one frame. Note that the signal line driver circuit may have means (D / A converter) for converting a digital signal into an analog signal.

  The above operation is the same in the shift register, the first latch circuit, and the second latch circuit included in the control means, and the correction video signal is input to the first latch circuit. The correction video signal is determined based on the storage means and the counting means.

  The storage means has at least a nonvolatile memory, and deterioration data of the light emitting element is recorded in the nonvolatile memory. That is, the degraded data is not erased even when the display device is turned off. In addition, display information is recorded in a volatile memory that the storage means may have.

  The signal supply source has a reference current source and a correction current source for each signal line, and a corrected signal current in consideration of deterioration is set in the signal supply source. In the present invention, it is not necessary to have a reference current source and a correction current source for each signal line, and there may be a single current source or a plurality of current sources.

  The counting means has a correction circuit and a correction data storage. The correction circuit has a counter circuit that accumulates the lighting time of the light emitting element, and accumulates the lighting time of the light emitting element. The accumulation of the lighting time by the counter circuit obtains the lighting time from the information of the video signal input from the signal line driving circuit to each light emitting element. The correction data storage unit records and stores information relating to the accumulated lighting time of the light emitting element, the deterioration state based on the lighting time, and the correction signal estimated from the basic data.

  A correction signal is input to the signal supply source based on the deterioration data stored in the nonvolatile memory and the lighting time of the light emitting element calculated by the counter circuit.

  A corrected signal current is created based on the reference current source and the correction current source of the signal supply source. Then, the generated correction current is supplied to each driving current source based on the correction signal that is sequentially input to the first latch circuit included in the control means and is transferred all at once to the second latch circuit.

  When the display device is driven, a high signal is sequentially input to each scanning line by the scanning line driving circuit, and each light emitting element, that is, each pixel is selected. In the selected pixel, a corrected signal current is supplied for each current line.

  As described above, by setting and supplying the signal current corresponding to the deterioration of the light emitting element, it is possible to prevent a decrease in luminance due to the deterioration and to prevent a decrease in image display quality.

  Note that the display device described in the embodiment is merely an example, and the present invention is not limited to this structure, that is, the structure and arrangement of each circuit. For example, a signal line driver circuit and a circuit such as a signal supply source may be provided in the same direction with respect to the pixel. Furthermore, the area occupied by the driver circuit may be reduced by sharing the shift register included in the signal line driver circuit and the shift register included in the control unit.

  Further, as specific configurations of the shift register, the first latch circuit, the second latch circuit, and the current source included in the control unit described in the embodiment, Japanese Patent Application Nos. 2001-333470, 2001-332904, Reference can be made to Japanese Patent Application Nos. 2001-335917, 2001-335918, and 2001-337208. Furthermore, as shown in Japanese Patent Application Nos. 2001-316116 and 2002-59903, a switching circuit may be provided between a signal source and a current source for setting a signal current included in the signal supply source or the like. As a result, even when a transistor included in the current source is deteriorated or has variation, the current source and the signal line are switched at regular intervals, so that more uniform display is possible.

(Embodiment 5)
In this embodiment, an example of a display device having a structure in which a control unit also serves as a signal supply source will be described with reference to FIGS.

  In FIG. 6, the reference current source and the correction current source included in the signal supply source and the current source included in the first latch circuit 502 or the second latch circuit 503 are shared. That is, FIG. 6 differs from FIG. 4 in that a control means 500 is provided in which the current source of the latch circuit also serves as the current source of the signal supply source 408.

  FIG. 7 shows a specific example of the control means 500 having the first latch circuit 502 and the second latch circuit 503. When the plurality of current sources included in the first latch circuit 502 are selected by the shift register 409, current is supplied from the reference current source 509. At this time, a video signal for correction signal corresponding to the deterioration of the light emitting element is input to the first latch circuit. When the switch SW805 connected to each current source is turned on, the corrected current is supplied to the current source included in the second latch circuit. When the SW 806 connected to the SW 805 via the inverter is turned on, the corrected current is supplied to the driving current source 13 included in each pixel via the current lines Dm to D (m + 2). When the video signal supplied from the signal line is turned on, the light emitting element emits light based on the corrected signal current.

  The specific configuration of the reference current source 509 in the present embodiment may be referred to FIG. 19, particularly the reference current source 509b.

  In the present invention, it is not necessary to have a reference current source and a correction current source for each signal line. Therefore, the current source included in the second latch circuit may be one for each signal line or plural.

  By sharing the current source in this way, it is possible to prevent a decrease in luminance due to deterioration of the light emitting element, and in addition to being able to prevent a decrease in image display quality, the cost related to the current source is reduced, Since the area occupied by the circuit portion is reduced, a narrow frame of the display device can be achieved.

  Note that the display device described in the embodiment is merely an example, and the present invention is not limited to this structure, that is, the structure and arrangement of each circuit. For example, a signal line driver circuit and a circuit such as a signal supply source may be provided in the same direction with respect to the pixel. Furthermore, the area occupied by the driver circuit may be reduced by sharing the shift register included in the signal line driver circuit and the shift register included in the control unit.

  Specific configurations of the shift register, the first latch circuit, the second latch circuit, and the current source included in the control unit described in the embodiment include Japanese Patent Application Nos. 2001-333470, 2001-332904, and Reference can be made to Japanese Patent Application No. 2001-335917, Japanese Patent Application No. 2001-335918, and Japanese Patent Application No. 2001-337208. Furthermore, as shown in Japanese Patent Application Nos. 2001-316116 and 2002-59903, a switching circuit may be provided between a signal source and a current source for setting a signal current included in the signal supply source or the like. As a result, even when a transistor included in the current source is deteriorated or has variation, the current source and the signal line are switched at regular intervals, so that more uniform display is possible.

(Embodiment 6)
In this embodiment, in the latch circuit of the control means, a pair of current sources is provided for each signal line, and the pair of current sources also serves as the signal supply source, that is, there is no signal supply source, and there is a single latch circuit of the control means. An example of a display device having a configuration that can be completed will be described with reference to FIGS.

  The structure shown in FIG. 8 is different from FIGS. 4 and 6 in that it has a control means 600 having a shift register and a latch circuit 602. In the latch circuit 602, since a pair of current sources are provided for each signal line, a single latch circuit is sufficient as compared with FIGS. Further, since the pair of current sources also serves as the reference current source and the correction current source, it is not necessary to provide a signal supply source.

  FIG. 9 shows a specific example of the control means 600 having the latch circuit 602. The correction signal video signal is input to the latch circuit 602 having a plurality of pairs of current sources. Based on the video signal for correction signal, current is supplied from the reference current source 509 to one of the pair of current sources. At this time, the current supplied based on the video signal for correction signal is corrected.

  While the corrected signal current is supplied to one current source (first current source) of the pair of current sources (setting period), the corrected signal is output from the other current source (second current source). A current is supplied to the driving current source via the current lines Dm to D (m + 1) (writing period). Switching between the setting period and the writing period is performed by switches SW905 and SW906 provided between the first current source and the second current source and the shift register. A switch SW907 is provided between the first current source and the second current source and the driving current source, and from which current source the corrected signal current is supplied to the driving current source. That is, which current source is used as the writing period is controlled.

  With the above-described configuration, it is possible to prevent a decrease in luminance due to deterioration of the light emitting element, to prevent a decrease in image display quality, and in addition, an area occupied by the circuit portion is reduced. Narrowing of the frame can be achieved.

  Note that the display device described in the embodiment is merely an example, and the present invention is not limited to this structure, that is, the structure and arrangement of each circuit. For example, a signal line driver circuit and a circuit such as a signal supply source may be provided in the same direction with respect to the pixel. Furthermore, the area occupied by the driver circuit may be reduced by sharing the shift register included in the signal line driver circuit and the shift register included in the signal supply source.

  However, it is preferable to provide a shift register for the video signal and for setting the corrected current value. This is because the video signal line shift register is required to be driven at a high frequency of about 1/60, but the current value setting shift register is driven at a frequency of about 1/20. This is because it is required to set a current value accurately corrected over time.

  Specific configurations of the shift register and the pair of current sources included in the control unit described in the embodiment include Japanese Patent Application No. 2001-333470, Japanese Patent Application No. 2001-332904, Japanese Patent Application No. 2001-335917, and Japanese Patent Application No. 2001-335918. Japanese Patent Application No. 2001-337208 can be referred to. Furthermore, as shown in Japanese Patent Application Nos. 2001-316116 and 2002-59903, a switching circuit may be provided between a signal source and a current source for setting a signal current included in the signal supply source or the like. As a result, even when a transistor included in the current source is deteriorated or has variation, the current source and the signal line are switched at regular intervals, so that more uniform display is possible.

(Embodiment 7)
In this embodiment, the timing for setting the corrected signal current will be described with reference to FIG.

  FIG. 10A shows a timing chart in the case where one frame period is divided into three subframe periods (SF1 to SF3). In each subframe period, scanning lines are sequentially selected, video periods are input from the signal lines (address periods) Ta1, Ta2, and Ta3, and a display period (lighting period) in which display is performed based on the video signals. Ts1, Ts2, and Ts3. Here, for the sake of explanation, the writing period is provided at the beginning of each subframe period. However, the present invention is not limited to this structure and may be provided in any of the subframe periods.

  FIGS. 10B and 10C show waveforms of setting signals for setting the corrected signal current. In FIG. 10B, the setting signal is High from the end of the writing period Ta1 to the start of Ta2. That is, a setting signal is input when writing is not being performed, and a corrected signal current is set. As shown in FIG. 10C, the setting signal may be High when writing is not performed in each subframe period. In this case, it is preferable because the set time can be increased.

  The period in which writing is not performed is a period in which the signal line driver circuit is not operating in order to write a video signal to the pixel. Therefore, the shift register and latch circuit of the signal line driver circuit, the shift register of the control unit, A latch circuit can also be shared. As a result, the drive circuit area is reduced, and a narrow frame can be achieved.

  Conversely, when a shift register and a latch circuit are provided in the signal line driver circuit and the control means, the corrected signal current can be set at any time. However, the timing for writing the corrected signal current to the driving current source is provided outside the writing period.

  The timing for setting the corrected signal current has been described above. However, the present invention is applicable to a case where driving is performed in a full frame period, even in a case where the subframe period is further finely divided and an erasing period is provided. Can do.

  Furthermore, the order of setting may be random, and can be set only for the pixels selected by the latch circuit of the control means.

  Thus, the timing for inputting the setting signal can be designed as appropriate. It goes without saying that the corrected signal current, that is, the current value can be accurately set by providing a long setting time.

(Embodiment 8)
As an electronic device using the display device of the present invention, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio, audio component, etc.), a notebook type personal computer, a game device, A portable information terminal (mobile computer, cellular phone, portable game machine, electronic book, or the like), an image reproducing apparatus (specifically, a digital versasatile disc (DVD) or the like) provided with a recording medium, A device having a display capable of displaying). In particular, it is desirable to use a display device for a portable information terminal that often has an opportunity to see the screen from an oblique direction because the wide viewing angle is regarded as important. Specific examples of these electronic devices are shown in FIGS.

  FIG. 17A illustrates a display device, which includes a housing 2001, a support base 2002, a display portion 2003, a speaker portion 2004, a video input terminal 2005, and the like. The display device of the present invention can be used for the display portion 2003. Further, the display device shown in FIG. 17A is completed by the present invention. Since the display device is a self-luminous type, a backlight is not required and a display portion thinner than a liquid crystal display can be obtained. The display device includes all information display devices for personal computers, TV broadcast reception, advertisement display, and the like.

  FIG. 17B illustrates a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103, operation keys 2104, an external connection port 2105, a shutter 2106, and the like. The display device of the present invention can be used for the display portion 2102.

    FIG. 17C illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. The display device of the present invention can be used for the display portion 2203.

  FIG. 17D illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. The display device of the present invention can be used for the display portion 2302.

  FIG. 17E illustrates a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion A2403, a display portion B2404, and a recording medium (DVD or the like). A reading unit 2405, operation keys 2406, a speaker unit 2407, and the like are included. Although the display portion A 2403 mainly displays image information and the display portion B 2404 mainly displays character information, the display device of the present invention can be used for these display portions A, B 2403, and 2404. Note that an image reproducing device provided with a recording medium includes a home game machine and the like.

  FIG. 17F illustrates a goggle type display (head mounted display), which includes a main body 2501, a display portion 2502, and an arm portion 2503. The display device of the present invention can be used for the display portion 2502.

  FIG. 17G illustrates a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control receiving portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, and an eyepiece. Part 2610 and the like. The display device of the present invention can be used for the display portion 2602.

  FIG. 17H illustrates a mobile phone, which includes a main body 2701, a housing 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. The display device of the present invention can be used for the display portion 2703. Note that the display portion 2703 can suppress current consumption of the mobile phone by displaying white characters on a black background.

  Further, since the light emitting portion of the display device consumes power, it is desirable to display information so that the light emitting portion is minimized. Therefore, when a display device is used for a display unit mainly including character information, such as a portable information terminal, particularly a mobile phone or a sound reproduction device, it is driven so that character information is formed by the light emitting part with the non-light emitting part as the background. It is desirable to do.

1 is a block diagram illustrating a display device of the present invention. 1 is an equivalent circuit diagram illustrating a pixel of the present invention. 1 is an equivalent circuit diagram illustrating a pixel of the present invention. 1 is a block diagram illustrating a display device of the present invention. 1 is a block diagram illustrating a display device of the present invention. 1 is a block diagram illustrating a display device of the present invention. 1 is a block diagram illustrating a display device of the present invention. 1 is a block diagram illustrating a display device of the present invention. 1 is a block diagram illustrating a display device of the present invention. FIG. 11 is a timing chart of a display device of the present invention. The figure which shows the basic data measurement of this invention. 1 is a block diagram illustrating a display device of the present invention. The figure which shows deterioration correction | amendment of the light emitting element of this invention. The figure which shows deterioration correction | amendment of the light emitting element of this invention. The figure which shows the deterioration state of a light emitting element. The figure which shows deterioration correction | amendment of the light emitting element of this invention. FIG. 14 illustrates an electronic device of the invention. FIG. 10 illustrates a display device including a light-emitting element. The figure which shows the reference | standard current source of this invention.

Claims (17)

A light emitting element, a first current source having a function of generating a second current, and a first function of controlling whether or not to supply the second current to the light emitting element in accordance with a video signal. A plurality of pixels each having a switch;
A source having the function of generating a first current ;
And a control means having a function of setting the value of the first current based on the deterioration of the light emitting element,
The first current source is electrically connected to the supply source via a first wiring;
The supply source has a second current source electrically connected to the first wiring, and a third current source electrically connected to the first wiring,
The value of the current generated by the second current source is set based on deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements of the plurality of pixels.
The second current is controlled for each pixel by controlling the first current source using the first current set based on the deterioration of the light emitting element for each pixel as a control signal. A display device characterized by being set. A light emitting element, a first current source having a function of generating a second current, and a first function of controlling whether or not to supply the second current to the light emitting element in accordance with a video signal. A plurality of pixels each having a switch;
A source having the function of generating a first current ;
And a control means having a function of setting the value of the first current based on the deterioration of the light emitting element,
The first current source is electrically connected to the supply source via a first wiring;
The source is
A second current source electrically connected to the first wiring;
A third current source electrically connected to the first wiring via a second switch;
A fourth current source electrically connected to the first wiring via a third switch;
A fifth current source electrically connected to the first wiring via a fourth switch;
The value of the current generated by the second current source is set based on deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements of the plurality of pixels.
The second current is controlled for each pixel by controlling the first current source using the first current set based on the deterioration of the light emitting element for each pixel as a control signal. A display device characterized by being set. A light emitting element, a first current source having a function of generating a second current, and a first function of controlling whether or not to supply the second current to the light emitting element in accordance with a video signal. A plurality of pixels each having a switch;
A source having the function of generating a first current ;
A counting unit having a function of measuring a lighting time of the light emitting element, and a function of generating a correction signal based on the lighting time of the light emitting element;
And a control means having a function of setting the value of the first current based on the correction signal,
The first current source is electrically connected to the supply source via a first wiring;
The supply source has a second current source electrically connected to the first wiring, and a third current source electrically connected to the first wiring,
The value of the current generated by the second current source is set based on deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements of the plurality of pixels.
The second current is controlled for each pixel by controlling the first current source using the first current set based on the deterioration of the light emitting element for each pixel as a control signal. A display device characterized by being set. A light emitting element, a first current source having a function of generating a second current, and a first function of controlling whether or not to supply the second current to the light emitting element in accordance with a video signal. A plurality of pixels each having a switch;
A source having the function of generating a first current ;
A counting unit having a function of measuring a lighting time of the light emitting element, and a function of generating a correction signal based on the lighting time of the light emitting element;
And a control means having a function of setting the value of the first current based on the correction signal,
The first current source is electrically connected to the supply source via a first wiring;
The source is
A second current source electrically connected to the first wiring;
A third current source electrically connected to the first wiring via a second switch;
A fourth current source electrically connected to the first wiring via a third switch;
A fifth current source electrically connected to the first wiring via a fourth switch;
The value of the current generated by the second current source is set based on deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements of the plurality of pixels.
The second current is controlled for each pixel by controlling the first current source using the first current set based on the deterioration of the light emitting element for each pixel as a control signal. A display device characterized by being set. A light emitting element, a first current source having a function of generating a second current, and a first function of controlling whether or not to supply the second current to the light emitting element in accordance with a video signal. A plurality of pixels each having a switch;
A source having the function of generating a first current ;
Storage means for storing the degradation information of the test light emitting element,
A counting unit having a function of measuring a lighting time of the light emitting element, and a function of generating a correction signal based on the lighting time of the light emitting element and the deterioration information of the test light emitting element;
And a control means having a function of setting the value of the first current based on the correction signal,
The first current source is electrically connected to the supply source via a first wiring;
The supply source has a second current source electrically connected to the first wiring, and a third current source electrically connected to the first wiring,
The value of the current generated by the second current source is set based on deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements of the plurality of pixels.
The second current is controlled for each pixel by controlling the first current source using the first current set based on the deterioration of the light emitting element for each pixel as a control signal. A display device characterized by being set. A light emitting element, a first current source having a function of generating a second current, and a first function of controlling whether or not to supply the second current to the light emitting element in accordance with a video signal. A plurality of pixels each having a switch;
A source having the function of generating a first current ;
Storage means for storing the degradation information of the test light emitting element,
A counting unit having a function of measuring a lighting time of the light emitting element, and a function of generating a correction signal based on the lighting time of the light emitting element and the deterioration information of the test light emitting element;
And a control means having a function of setting the value of the first current based on the correction signal,
The first current source is electrically connected to the supply source via a first wiring;
The source is
A second current source electrically connected to the first wiring;
A third current source electrically connected to the first wiring via a second switch;
A fourth current source electrically connected to the first wiring via a third switch;
A fifth current source electrically connected to the first wiring via a fourth switch;
The value of the current generated by the second current source is set based on deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements of the plurality of pixels.
The second current is controlled for each pixel by controlling the first current source using the first current set based on the deterioration of the light emitting element for each pixel as a control signal. A display device characterized by being set. In claim 5 or claim 6 ,
The storage means
A nonvolatile memory in which the deterioration information of the test light emitting element is stored;
And a volatile memory in which display information is stored. In any one of Claims 3 thru | or 7 ,
The counting means includes
A counter circuit having a function of measuring the lighting time of the light emitting element;
A display device comprising: a correction data storage unit that stores information on the correction signal and a lighting time of the light emitting element. In any one of Claim 2, Claim 4, and Claim 6 ,
The display device, wherein a current generated by the third current source, a current generated by the fourth current source, and a current generated by the fifth current source are different from each other. In any one of Claims 1 thru | or 9 ,
The display device characterized in that the control means includes a shift register circuit or a decoder circuit, a first latch circuit, and a second latch circuit. A plurality of pixels each having a light emitting element, a first current source having a function of generating a second current, and a first switch connected between the first current source and the light emitting element; a supply source having a function of generating a first current, a possess,
The supply source has a second current source electrically connected to the first wiring, and a third current source electrically connected to the first wiring,
The first current source, said a source electrically connected to the driving method of the Ru display device via the first wiring,
Based on the deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements each of the plurality of pixels has, sets the value of the current generated by the second current source,
Setting a value of the first current based on degradation of the light emitting element;
The value of the second current is set for each pixel by controlling the first current source using the first current set based on deterioration of the light emitting element for each pixel as a control signal. ,
A method for driving a display device, wherein the first switch is controlled in accordance with a video signal. A plurality of pixels each having a light emitting element, a first current source having a function of generating a second current, and a first switch connected between the first current source and the light emitting element; a supply source having a function of generating a first current, a possess,
The supply source includes: a second current source electrically connected to the first wiring; a third current source electrically connected to the first wiring via a second switch; A fourth current source electrically connected to the first wiring via a third switch; and a fifth current source electrically connected to the first wiring via a fourth switch. And having
The first current source, said a source electrically connected to the driving method of the Ru display device via the first wiring,
Controlling the value of the first current by controlling on or off of the second switch, the third switch and the fourth switch;
Based on the deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements each of the plurality of pixels has, sets the value of the current generated by the second current source,
Setting a value of the first current based on degradation of the light emitting element;
The value of the second current is set for each pixel by controlling the first current source using the first current set based on deterioration of the light emitting element for each pixel as a control signal. ,
A method for driving a display device, wherein the first switch is controlled in accordance with a video signal. A plurality of pixels each having a light emitting element, a first current source having a function of generating a second current, and a first switch connected between the first current source and the light emitting element; a supply source having a function of generating a first current, a possess,
The supply source has a second current source electrically connected to the first wiring, and a third current source electrically connected to the first wiring,
The first current source, said a source electrically connected to the driving method of the Ru display device via the first wiring,
Based on the deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements each of the plurality of pixels has, sets the value of the current generated by the second current source,
Measure the lighting time of the light emitting element,
A correction signal is generated based on the lighting time of the light emitting element,
Setting the value of the first current based on the correction signal;
The value of the second current is set for each pixel by controlling the first current source using the first current set based on deterioration of the light emitting element for each pixel as a control signal. ,
A method for driving a display device, wherein the first switch is controlled in accordance with a video signal. A plurality of pixels each having a light emitting element, a first current source having a function of generating a second current, and a first switch connected between the first current source and the light emitting element; a supply source having a function of generating a first current, a possess,
The supply source includes: a second current source electrically connected to the first wiring; a third current source electrically connected to the first wiring via a second switch; A fourth current source electrically connected to the first wiring via a third switch; and a fifth current source electrically connected to the first wiring via a fourth switch. And having
The first current source, said a source electrically connected to the driving method of the Ru display device via the first wiring,
Controlling the value of the first current by controlling on or off of the second switch, the third switch and the fourth switch;
Based on the deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements each of the plurality of pixels has, sets the value of the current generated by the second current source,
Measure the lighting time of the light emitting element,
A correction signal is generated based on the lighting time of the light emitting element,
Setting the value of the first current based on the correction signal;
The value of the second current is set for each pixel by controlling the first current source using the first current set based on deterioration of the light emitting element for each pixel as a control signal. ,
A method for driving a display device, wherein the first switch is controlled in accordance with a video signal. A plurality of pixels each having a light emitting element, a first current source having a function of generating a second current, and a first switch connected between the first current source and the light emitting element; a supply source having a function of generating a first current, storage means for storing the degradation information of the testing light emitting device, was closed,
The supply source has a second current source electrically connected to the first wiring, and a third current source electrically connected to the first wiring,
The first current source, said a source electrically connected to the driving method of the Ru display device via the first wiring,
Based on the deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements each of the plurality of pixels has, sets the value of the current generated by the second current source,
Measure the lighting time of the light emitting element,
A correction signal is generated based on the lighting time of the light emitting element and the deterioration information of the test light emitting element,
Setting the value of the first current based on the correction signal;
The value of the second current is set for each pixel by controlling the first current source using the first current set based on deterioration of the light emitting element for each pixel as a control signal. ,
A method for driving a display device, wherein the first switch is controlled in accordance with a video signal. A plurality of pixels each having a light emitting element, a first current source having a function of generating a second current, and a first switch connected between the first current source and the light emitting element; a supply source having a function of generating a first current, storage means for storing the degradation information of the testing light emitting device, was closed,
The supply source includes: a second current source electrically connected to the first wiring; a third current source electrically connected to the first wiring via a second switch; A fourth current source electrically connected to the first wiring via a third switch; and a fifth current source electrically connected to the first wiring via a fourth switch. And having
The first current source, said a source electrically connected to the driving method of the Ru display device via the first wiring,
Controlling the value of the first current by controlling on or off of the second switch, the third switch and the fourth switch;
Based on the deterioration of the light emitting element that has a minimum or maximum deterioration state among the light emitting elements each of the plurality of pixels has, sets the value of the current generated by the second current source,
Measure the lighting time of the light emitting element,
A correction signal is generated based on the lighting time of the light emitting element and the deterioration information of the test light emitting element,
Setting the value of the first current based on the correction signal;
The value of the second current is set for each pixel by controlling the first current source using the first current set based on deterioration of the light emitting element for each pixel as a control signal. ,
A method for driving a display device, wherein the first switch is controlled in accordance with a video signal. In any one of Claims 12, 14, and 16 ,
The display device driving method , wherein a current generated by the third current source, a current generated by the fourth current source, and a current generated by the fifth current source are different from each other.

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